diff options
Diffstat (limited to 'src/grp-resolve/systemd-resolved')
55 files changed, 19344 insertions, 0 deletions
diff --git a/src/grp-resolve/systemd-resolved/.gitignore b/src/grp-resolve/systemd-resolved/.gitignore new file mode 100644 index 0000000000..f0835923b7 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/.gitignore @@ -0,0 +1,6 @@ +/resolved-gperf.c +/resolved.conf +/dns_type-from-name.gperf +/dns_type-from-name.h +/dns_type-list.txt +/dns_type-to-name.h diff --git a/src/grp-resolve/systemd-resolved/Makefile b/src/grp-resolve/systemd-resolved/Makefile new file mode 100644 index 0000000000..e8ae8ccc28 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/Makefile @@ -0,0 +1,127 @@ +# -*- Mode: makefile; indent-tabs-mode: t -*- +# +# This file is part of systemd. +# +# Copyright 2010-2012 Lennart Poettering +# Copyright 2010-2012 Kay Sievers +# Copyright 2013 Zbigniew Jędrzejewski-Szmek +# Copyright 2013 David Strauss +# Copyright 2016 Luke Shumaker +# +# systemd is free software; you can redistribute it and/or modify it +# under the terms of the GNU Lesser General Public License as published by +# the Free Software Foundation; either version 2.1 of the License, or +# (at your option) any later version. +# +# systemd is distributed in the hope that it will be useful, but +# WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +# Lesser General Public License for more details. +# +# You should have received a copy of the GNU Lesser General Public License +# along with systemd; If not, see <http://www.gnu.org/licenses/>. +include $(dir $(lastword $(MAKEFILE_LIST)))/../../../config.mk +include $(topsrcdir)/build-aux/Makefile.head.mk + +ifneq ($(ENABLE_RESOLVED),) + +systemd_resolved_SOURCES = \ + src/resolve/resolved.c \ + src/resolve/resolved-manager.c \ + src/resolve/resolved-manager.h \ + src/resolve/resolved-conf.c \ + src/resolve/resolved-conf.h \ + src/resolve/resolved-resolv-conf.c \ + src/resolve/resolved-resolv-conf.h \ + src/resolve/resolved-bus.c \ + src/resolve/resolved-bus.h \ + src/resolve/resolved-link.h \ + src/resolve/resolved-link.c \ + src/resolve/resolved-link-bus.c \ + src/resolve/resolved-link-bus.h \ + src/resolve/resolved-llmnr.h \ + src/resolve/resolved-llmnr.c \ + src/resolve/resolved-mdns.h \ + src/resolve/resolved-mdns.c \ + src/resolve/resolved-def.h \ + $(basic_dns_sources) \ + src/resolve/resolved-dns-query.h \ + src/resolve/resolved-dns-query.c \ + src/resolve/resolved-dns-synthesize.h \ + src/resolve/resolved-dns-synthesize.c \ + src/resolve/resolved-dns-transaction.h \ + src/resolve/resolved-dns-transaction.c \ + src/resolve/resolved-dns-scope.h \ + src/resolve/resolved-dns-scope.c \ + src/resolve/resolved-dns-server.h \ + src/resolve/resolved-dns-server.c \ + src/resolve/resolved-dns-search-domain.h \ + src/resolve/resolved-dns-search-domain.c \ + src/resolve/resolved-dns-cache.h \ + src/resolve/resolved-dns-cache.c \ + src/resolve/resolved-dns-zone.h \ + src/resolve/resolved-dns-zone.c \ + src/resolve/resolved-dns-stream.h \ + src/resolve/resolved-dns-stream.c \ + src/resolve/resolved-dns-trust-anchor.h \ + src/resolve/resolved-dns-trust-anchor.c \ + src/resolve/resolved-dns-stub.h \ + src/resolve/resolved-dns-stub.c \ + src/resolve/resolved-etc-hosts.h \ + src/resolve/resolved-etc-hosts.c \ + src/shared/gcrypt-util.c \ + src/shared/gcrypt-util.h + +nodist_systemd_resolved_SOURCES = \ + src/resolve/dns_type-from-name.h \ + src/resolve/dns_type-to-name.h \ + src/resolve/resolved-gperf.c + +systemd_resolved_CFLAGS = \ + $(GCRYPT_CFLAGS) + +systemd_resolved_LDADD = \ + libsystemd-network.la \ + libsystemd-shared.la \ + $(GCRYPT_LIBS) \ + -lm + +rootlibexec_PROGRAMS += \ + systemd-resolved + +nodist_systemunit_DATA += \ + units/systemd-resolved.service + +dist_systemunit_DATA_busnames += \ + units/org.freedesktop.resolve1.busname + +dist_dbuspolicy_DATA += \ + src/resolve/org.freedesktop.resolve1.conf + +dist_dbussystemservice_DATA += \ + src/resolve/org.freedesktop.resolve1.service + +SYSTEM_UNIT_ALIASES += \ + systemd-resolved.service dbus-org.freedesktop.resolve1.service + +BUSNAMES_TARGET_WANTS += \ + org.freedesktop.resolve1.busname + +GENERAL_ALIASES += \ + $(systemunitdir)/systemd-resolved.service $(pkgsysconfdir)/system/multi-user.target.wants/systemd-resolved.service + +nodist_pkgsysconf_DATA += \ + src/resolve/resolved.conf + +endif # ENABLE_RESOLVED +gperf_gperf_sources += \ + src/resolve/resolved-gperf.gperf + +EXTRA_DIST += \ + units/systemd-resolved.service.m4.in \ + src/resolve/resolved.conf.in + +dist_rootlibexec_DATA += \ + src/resolve/resolv.conf + +include $(topsrcdir)/build-aux/Makefile.tail.mk diff --git a/src/grp-resolve/systemd-resolved/RFCs b/src/grp-resolve/systemd-resolved/RFCs new file mode 100644 index 0000000000..09c85f9518 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/RFCs @@ -0,0 +1,59 @@ +Y = Comprehensively Implemented, to the point appropriate for resolved +D = Comprehensively Implemented, by a dependency of resolved +! = Missing and something we might want to implement +~ = Needs no explicit support or doesn't apply +? = Is this relevant today? + = We are working on this + +Y https://tools.ietf.org/html/rfc1034 → DOMAIN NAMES - CONCEPTS AND FACILITIES +Y https://tools.ietf.org/html/rfc1035 → DOMAIN NAMES - IMPLEMENTATION AND SPECIFICATION +? https://tools.ietf.org/html/rfc1101 → DNS Encoding of Network Names and Other Types +Y https://tools.ietf.org/html/rfc1123 → Requirements for Internet Hosts — Application and Support +~ https://tools.ietf.org/html/rfc1464 → Using the Domain Name System To Store Arbitrary String Attributes +Y https://tools.ietf.org/html/rfc1536 → Common DNS Implementation Errors and Suggested Fixes +Y https://tools.ietf.org/html/rfc1876 → A Means for Expressing Location Information in the Domain Name System +Y https://tools.ietf.org/html/rfc2181 → Clarifications to the DNS Specification +Y https://tools.ietf.org/html/rfc2308 → Negative Caching of DNS Queries (DNS NCACHE) +Y https://tools.ietf.org/html/rfc2782 → A DNS RR for specifying the location of services (DNS SRV) +D https://tools.ietf.org/html/rfc3492 → Punycode: A Bootstring encoding of Unicode for Internationalized Domain Names in Applications (IDNA) +Y https://tools.ietf.org/html/rfc3596 → DNS Extensions to Support IP Version 6 +Y https://tools.ietf.org/html/rfc3597 → Handling of Unknown DNS Resource Record (RR) Types +Y https://tools.ietf.org/html/rfc4033 → DNS Security Introduction and Requirements +Y https://tools.ietf.org/html/rfc4034 → Resource Records for the DNS Security Extensions +Y https://tools.ietf.org/html/rfc4035 → Protocol Modifications for the DNS Security Extensions +! https://tools.ietf.org/html/rfc4183 → A Suggested Scheme for DNS Resolution of Networks and Gateways +Y https://tools.ietf.org/html/rfc4255 → Using DNS to Securely Publish Secure Shell (SSH) Key Fingerprints +Y https://tools.ietf.org/html/rfc4343 → Domain Name System (DNS) Case Insensitivity Clarification +~ https://tools.ietf.org/html/rfc4470 → Minimally Covering NSEC Records and DNSSEC On-line Signing +Y https://tools.ietf.org/html/rfc4501 → Domain Name System Uniform Resource Identifiers +Y https://tools.ietf.org/html/rfc4509 → Use of SHA-256 in DNSSEC Delegation Signer (DS) Resource Records (RRs) +~ https://tools.ietf.org/html/rfc4592 → The Role of Wildcards in the Domain Name System +~ https://tools.ietf.org/html/rfc4697 → Observed DNS Resolution Misbehavior +Y https://tools.ietf.org/html/rfc4795 → Link-Local Multicast Name Resolution (LLMNR) +Y https://tools.ietf.org/html/rfc5011 → Automated Updates of DNS Security (DNSSEC) Trust Anchors +Y https://tools.ietf.org/html/rfc5155 → DNS Security (DNSSEC) Hashed Authenticated Denial of Existence +Y https://tools.ietf.org/html/rfc5452 → Measures for Making DNS More Resilient against Forged Answers +Y https://tools.ietf.org/html/rfc5702 → Use of SHA-2 Algorithms with RSA in DNSKEY and RRSIG Resource Records for DNSSEC +Y https://tools.ietf.org/html/rfc5890 → Internationalized Domain Names for Applications (IDNA): Definitions and Document Framework +Y https://tools.ietf.org/html/rfc5891 → Internationalized Domain Names in Applications (IDNA): Protocol +Y https://tools.ietf.org/html/rfc5966 → DNS Transport over TCP - Implementation Requirements +Y https://tools.ietf.org/html/rfc6303 → Locally Served DNS Zones +Y https://tools.ietf.org/html/rfc6604 → xNAME RCODE and Status Bits Clarification +Y https://tools.ietf.org/html/rfc6605 → Elliptic Curve Digital Signature Algorithm (DSA) for DNSSEC + https://tools.ietf.org/html/rfc6672 → DNAME Redirection in the DNS +! https://tools.ietf.org/html/rfc6731 → Improved Recursive DNS Server Selection for Multi-Interfaced Nodes +Y https://tools.ietf.org/html/rfc6761 → Special-Use Domain Names + https://tools.ietf.org/html/rfc6762 → Multicast DNS + https://tools.ietf.org/html/rfc6763 → DNS-Based Service Discovery +~ https://tools.ietf.org/html/rfc6781 → DNSSEC Operational Practices, Version 2 +Y https://tools.ietf.org/html/rfc6840 → Clarifications and Implementation Notes for DNS Security (DNSSEC) +Y https://tools.ietf.org/html/rfc6891 → Extension Mechanisms for DNS (EDNS(0)) +Y https://tools.ietf.org/html/rfc6944 → Applicability Statement: DNS Security (DNSSEC) DNSKEY Algorithm Implementation Status +Y https://tools.ietf.org/html/rfc6975 → Signaling Cryptographic Algorithm Understanding in DNS Security Extensions (DNSSEC) +Y https://tools.ietf.org/html/rfc7129 → Authenticated Denial of Existence in the DNS +Y https://tools.ietf.org/html/rfc7646 → Definition and Use of DNSSEC Negative Trust Anchors +~ https://tools.ietf.org/html/rfc7719 → DNS Terminology + +Also relevant: + + https://www.iab.org/documents/correspondence-reports-documents/2013-2/iab-statement-dotless-domains-considered-harmful/ diff --git a/src/grp-resolve/systemd-resolved/dnssec-trust-anchors.d.xml b/src/grp-resolve/systemd-resolved/dnssec-trust-anchors.d.xml new file mode 100644 index 0000000000..9a28862ceb --- /dev/null +++ b/src/grp-resolve/systemd-resolved/dnssec-trust-anchors.d.xml @@ -0,0 +1,198 @@ +<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*--> +<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" + "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> + +<!-- + This file is part of systemd. + + Copyright 2016 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +--> + +<refentry id="dnssec-trust-anchors.d" conditional='ENABLE_RESOLVED' + xmlns:xi="http://www.w3.org/2001/XInclude"> + <refentryinfo> + <title>dnssec-trust-anchors.d</title> + <productname>systemd</productname> + + <authorgroup> + <author> + <contrib>Developer</contrib> + <firstname>Lennart</firstname> + <surname>Poettering</surname> + <email>lennart@poettering.net</email> + </author> + </authorgroup> + </refentryinfo> + + <refmeta> + <refentrytitle>dnssec-trust-anchors.d</refentrytitle> + <manvolnum>5</manvolnum> + </refmeta> + + <refnamediv> + <refname>dnssec-trust-anchors.d</refname> + <refname>systemd.positive</refname> + <refname>systemd.negative</refname> + <refpurpose>DNSSEC trust anchor configuration files</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <para><filename>/etc/dnssec-trust-anchors.d/*.positive</filename></para> + <para><filename>/run/dnssec-trust-anchors.d/*.positive</filename></para> + <para><filename>/usr/lib/dnssec-trust-anchors.d/*.positive</filename></para> + <para><filename>/etc/dnssec-trust-anchors.d/*.negative</filename></para> + <para><filename>/run/dnssec-trust-anchors.d/*.negative</filename></para> + <para><filename>/usr/lib/dnssec-trust-anchors.d/*.negative</filename></para> + </refsynopsisdiv> + + <refsect1> + <title>Description</title> + + <para>The DNSSEC trust anchor configuration files define positive + and negative trust anchors + <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> + bases DNSSEC integrity proofs on.</para> + </refsect1> + + <refsect1> + <title>Positive Trust Anchors</title> + + <para>Positive trust anchor configuration files contain DNSKEY and + DS resource record definitions to use as base for DNSSEC integrity + proofs. See <ulink + url="https://tools.ietf.org/html/rfc4035#section-4.4">RFC 4035, + Section 4.4</ulink> for more information about DNSSEC trust + anchors.</para> + + <para>Positive trust anchors are read from files with the suffix + <filename>.positive</filename> located in + <filename>/etc/dnssec-trust-anchors.d/</filename>, + <filename>/run/dnssec-trust-anchors.d/</filename> and + <filename>/usr/lib/dnssec-trust-anchors.d/</filename>. These + directories are searched in the specified order, and a trust + anchor file of the same name in an earlier path overrides a trust + anchor files in a later path. To disable a trust anchor file + shipped in <filename>/usr/lib/dnssec-trust-anchors.d/</filename> + it is sufficient to provide an identically-named file in + <filename>/etc/dnssec-trust-anchors.d/</filename> or + <filename>/run/dnssec-trust-anchors.d/</filename> that is either + empty or a symlink to <filename>/dev/null</filename> ("masked").</para> + + <para>Positive trust anchor files are simple text files resembling + DNS zone files, as documented in <ulink + url="https://tools.ietf.org/html/rfc1035#section-5">RFC 1035, Section + 5</ulink>. One DS or DNSKEY resource record may be listed per + line. Empty lines and lines starting with a semicolon + (<literal>;</literal>) are ignored and considered comments. A DS + resource record is specified like in the following example:</para> + + <programlisting>. IN DS 19036 8 2 49aac11d7b6f6446702e54a1607371607a1a41855200fd2ce1cdde32f24e8fb5</programlisting> + + <para>The first word specifies the domain, use + <literal>.</literal> for the root domain. The domain may be + specified with or without trailing dot, which is considered + equivalent. The second word must be <literal>IN</literal> the + third word <literal>DS</literal>. The following words specify the + key tag, signature algorithm, digest algorithm, followed by the + hex-encoded key fingerprint. See <ulink + url="https://tools.ietf.org/html/rfc4034#section-5">RFC 4034, + Section 5</ulink> for details about the precise syntax and meaning + of these fields.</para> + + <para>Alternatively, DNSKEY resource records may be used to define + trust anchors, like in the following example:</para> + + <programlisting>. IN DNSKEY 257 3 8 AwEAAagAIKlVZrpC6Ia7gEzahOR+9W29euxhJhVVLOyQbSEW0O8gcCjFFVQUTf6v58fLjwBd0YI0EzrAcQqBGCzh/RStIoO8g0NfnfL2MTJRkxoXbfDaUeVPQuYEhg37NZWAJQ9VnMVDxP/VHL496M/QZxkjf5/Efucp2gaDX6RS6CXpoY68LsvPVjR0ZSwzz1apAzvN9dlzEheX7ICJBBtuA6G3LQpzW5hOA2hzCTMjJPJ8LbqF6dsV6DoBQzgul0sGIcGOYl7OyQdXfZ57relSQageu+ipAdTTJ25AsRTAoub8ONGcLmqrAmRLKBP1dfwhYB4N7knNnulqQxA+Uk1ihz0=</programlisting> + + <para>The first word specifies the domain again, the second word + must be <literal>IN</literal>, followed by + <literal>DNSKEY</literal>. The subsequent words encode the DNSKEY + flags, protocol and algorithm fields, followed by the key data + encoded in Base64. See <ulink + url="https://tools.ietf.org/html/rfc4034#section-2">RFC 4034, + Section 2</ulink> for details about the precise syntax and meaning + of these fields.</para> + + <para>If multiple DS or DNSKEY records are defined for the same + domain (possibly even in different trust anchor files), all keys + are used and are considered equivalent as base for DNSSEC + proofs.</para> + + <para>Note that <filename>systemd-resolved</filename> will + automatically use a built-in trust anchor key for the Internet + root domain if no positive trust anchors are defined for the root + domain. In most cases it is hence unnecessary to define an + explicit key with trust anchor files. The built-in key is disabled + as soon as at least one trust anchor key for the root domain is + defined in trust anchor files.</para> + + <para>It is generally recommended to encode trust anchors in DS + resource records, rather than DNSKEY resource records.</para> + + <para>If a trust anchor specified via a DS record is found revoked + it is automatically removed from the trust anchor database for the + runtime. See <ulink url="https://tools.ietf.org/html/rfc5011">RFC + 5011</ulink> for details about revoked trust anchors. Note that + <filename>systemd-resolved</filename> will not update its trust + anchor database from DNS servers automatically. Instead, it is + recommended to update the resolver software or update the new + trust anchor via adding in new trust anchor files.</para> + + <para>The current DNSSEC trust anchor for the Internet's root + domain is available at the <ulink + url="https://data.iana.org/root-anchors/root-anchors.xml">IANA + Trust Anchor and Keys</ulink> page.</para> + </refsect1> + + <refsect1> + <title>Negative Trust Anchors</title> + + <para>Negative trust anchors define domains where DNSSEC validation shall be turned + off. Negative trust anchor files are found at the same location as positive trust anchor files, + and follow the same overriding rules. They are text files with the + <filename>.negative</filename> suffix. Empty lines and lines whose first character is + <literal>;</literal> are ignored. Each line specifies one domain name which is the root of a DNS + subtree where validation shall be disabled.</para> + + <para>Negative trust anchors are useful to support private DNS + subtrees that are not referenced from the Internet DNS hierarchy, + and not signed.</para> + + <para><ulink url="https://tools.ietf.org/html/rfc7646">RFC + 7646</ulink> for details on negative trust anchors.</para> + + <para>If no negative trust anchor files are configured a built-in + set of well-known private DNS zone domains is used as negative + trust anchors.</para> + + <para>It is also possibly to define per-interface negative trust + anchors using the <varname>DNSSECNegativeTrustAnchors=</varname> + setting in + <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry> + files.</para> + </refsect1> + + <refsect1> + <title>See Also</title> + <para> + <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, + <citerefentry><refentrytitle>resolved.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry> + </para> + </refsect1> + +</refentry> diff --git a/src/grp-resolve/systemd-resolved/org.freedesktop.resolve1.conf b/src/grp-resolve/systemd-resolved/org.freedesktop.resolve1.conf new file mode 100644 index 0000000000..25b09774e5 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/org.freedesktop.resolve1.conf @@ -0,0 +1,27 @@ +<?xml version="1.0"?> <!--*-nxml-*--> +<!DOCTYPE busconfig PUBLIC "-//freedesktop//DTD D-BUS Bus Configuration 1.0//EN" + "http://www.freedesktop.org/standards/dbus/1.0/busconfig.dtd"> + +<!-- + This file is part of systemd. + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. +--> + +<busconfig> + + <policy user="systemd-resolve"> + <allow own="org.freedesktop.resolve1"/> + <allow send_destination="org.freedesktop.resolve1"/> + <allow receive_sender="org.freedesktop.resolve1"/> + </policy> + + <policy context="default"> + <allow send_destination="org.freedesktop.resolve1"/> + <allow receive_sender="org.freedesktop.resolve1"/> + </policy> + +</busconfig> diff --git a/src/grp-resolve/systemd-resolved/org.freedesktop.resolve1.service b/src/grp-resolve/systemd-resolved/org.freedesktop.resolve1.service new file mode 100644 index 0000000000..7ac5c323f0 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/org.freedesktop.resolve1.service @@ -0,0 +1,12 @@ +# This file is part of systemd. +# +# systemd is free software; you can redistribute it and/or modify it +# under the terms of the GNU Lesser General Public License as published by +# the Free Software Foundation; either version 2.1 of the License, or +# (at your option) any later version. + +[D-BUS Service] +Name=org.freedesktop.resolve1 +Exec=/bin/false +User=root +SystemdService=dbus-org.freedesktop.resolve1.service diff --git a/src/grp-resolve/systemd-resolved/resolv.conf b/src/grp-resolve/systemd-resolved/resolv.conf new file mode 100644 index 0000000000..b8034d6829 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolv.conf @@ -0,0 +1,11 @@ +# This is a static resolv.conf file for connecting local clients to +# systemd-resolved via its DNS stub listener on 127.0.0.53. +# +# Third party programs must not access this file directly, but only through the +# symlink at /etc/resolv.conf. To manage resolv.conf(5) in a different way, +# replace this symlink by a static file or a different symlink. +# +# See systemd-resolved.service(8) for details about the supported modes of +# operation for /etc/resolv.conf. + +nameserver 127.0.0.53 diff --git a/src/grp-resolve/systemd-resolved/resolved-bus.c b/src/grp-resolve/systemd-resolved/resolved-bus.c new file mode 100644 index 0000000000..ec63fb2900 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-bus.c @@ -0,0 +1,1690 @@ +/*** + This file is part of systemd. + + Copyright 2014 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include "basic-dns/resolved-def.h" +#include "sd-bus/bus-common-errors.h" +#include "sd-bus/bus-util.h" +#include "systemd-basic/alloc-util.h" +#include "systemd-shared/dns-domain.h" + +#include "resolved-bus.h" +#include "resolved-dns-synthesize.h" +#include "resolved-link-bus.h" + +static int reply_query_state(DnsQuery *q) { + + switch (q->state) { + + case DNS_TRANSACTION_NO_SERVERS: + return sd_bus_reply_method_errorf(q->request, BUS_ERROR_NO_NAME_SERVERS, "No appropriate name servers or networks for name found"); + + case DNS_TRANSACTION_TIMEOUT: + return sd_bus_reply_method_errorf(q->request, SD_BUS_ERROR_TIMEOUT, "Query timed out"); + + case DNS_TRANSACTION_ATTEMPTS_MAX_REACHED: + return sd_bus_reply_method_errorf(q->request, SD_BUS_ERROR_TIMEOUT, "All attempts to contact name servers or networks failed"); + + case DNS_TRANSACTION_INVALID_REPLY: + return sd_bus_reply_method_errorf(q->request, BUS_ERROR_INVALID_REPLY, "Received invalid reply"); + + case DNS_TRANSACTION_ERRNO: + return sd_bus_reply_method_errnof(q->request, q->answer_errno, "Lookup failed due to system error: %m"); + + case DNS_TRANSACTION_ABORTED: + return sd_bus_reply_method_errorf(q->request, BUS_ERROR_ABORTED, "Query aborted"); + + case DNS_TRANSACTION_DNSSEC_FAILED: + return sd_bus_reply_method_errorf(q->request, BUS_ERROR_DNSSEC_FAILED, "DNSSEC validation failed: %s", + dnssec_result_to_string(q->answer_dnssec_result)); + + case DNS_TRANSACTION_NO_TRUST_ANCHOR: + return sd_bus_reply_method_errorf(q->request, BUS_ERROR_NO_TRUST_ANCHOR, "No suitable trust anchor known"); + + case DNS_TRANSACTION_RR_TYPE_UNSUPPORTED: + return sd_bus_reply_method_errorf(q->request, BUS_ERROR_RR_TYPE_UNSUPPORTED, "Server does not support requested resource record type"); + + case DNS_TRANSACTION_NETWORK_DOWN: + return sd_bus_reply_method_errorf(q->request, BUS_ERROR_NETWORK_DOWN, "Network is down"); + + case DNS_TRANSACTION_NOT_FOUND: + /* We return this as NXDOMAIN. This is only generated when a host doesn't implement LLMNR/TCP, and we + * thus quickly know that we cannot resolve an in-addr.arpa or ip6.arpa address. */ + return sd_bus_reply_method_errorf(q->request, _BUS_ERROR_DNS "NXDOMAIN", "'%s' not found", dns_query_string(q)); + + case DNS_TRANSACTION_RCODE_FAILURE: { + _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL; + + if (q->answer_rcode == DNS_RCODE_NXDOMAIN) + sd_bus_error_setf(&error, _BUS_ERROR_DNS "NXDOMAIN", "'%s' not found", dns_query_string(q)); + else { + const char *rc, *n; + char p[DECIMAL_STR_MAX(q->answer_rcode)]; + + rc = dns_rcode_to_string(q->answer_rcode); + if (!rc) { + sprintf(p, "%i", q->answer_rcode); + rc = p; + } + + n = strjoina(_BUS_ERROR_DNS, rc); + sd_bus_error_setf(&error, n, "Could not resolve '%s', server or network returned error %s", dns_query_string(q), rc); + } + + return sd_bus_reply_method_error(q->request, &error); + } + + case DNS_TRANSACTION_NULL: + case DNS_TRANSACTION_PENDING: + case DNS_TRANSACTION_VALIDATING: + case DNS_TRANSACTION_SUCCESS: + default: + assert_not_reached("Impossible state"); + } +} + +static int append_address(sd_bus_message *reply, DnsResourceRecord *rr, int ifindex) { + int r; + + assert(reply); + assert(rr); + + r = sd_bus_message_open_container(reply, 'r', "iiay"); + if (r < 0) + return r; + + r = sd_bus_message_append(reply, "i", ifindex); + if (r < 0) + return r; + + if (rr->key->type == DNS_TYPE_A) { + r = sd_bus_message_append(reply, "i", AF_INET); + if (r < 0) + return r; + + r = sd_bus_message_append_array(reply, 'y', &rr->a.in_addr, sizeof(struct in_addr)); + + } else if (rr->key->type == DNS_TYPE_AAAA) { + r = sd_bus_message_append(reply, "i", AF_INET6); + if (r < 0) + return r; + + r = sd_bus_message_append_array(reply, 'y', &rr->aaaa.in6_addr, sizeof(struct in6_addr)); + } else + return -EAFNOSUPPORT; + + if (r < 0) + return r; + + r = sd_bus_message_close_container(reply); + if (r < 0) + return r; + + return 0; +} + +static void bus_method_resolve_hostname_complete(DnsQuery *q) { + _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *canonical = NULL; + _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL; + _cleanup_free_ char *normalized = NULL; + DnsResourceRecord *rr; + unsigned added = 0; + int ifindex, r; + + assert(q); + + if (q->state != DNS_TRANSACTION_SUCCESS) { + r = reply_query_state(q); + goto finish; + } + + r = dns_query_process_cname(q); + if (r == -ELOOP) { + r = sd_bus_reply_method_errorf(q->request, BUS_ERROR_CNAME_LOOP, "CNAME loop detected, or CNAME resolving disabled on '%s'", dns_query_string(q)); + goto finish; + } + if (r < 0) + goto finish; + if (r == DNS_QUERY_RESTARTED) /* This was a cname, and the query was restarted. */ + return; + + r = sd_bus_message_new_method_return(q->request, &reply); + if (r < 0) + goto finish; + + r = sd_bus_message_open_container(reply, 'a', "(iiay)"); + if (r < 0) + goto finish; + + DNS_ANSWER_FOREACH_IFINDEX(rr, ifindex, q->answer) { + DnsQuestion *question; + + question = dns_query_question_for_protocol(q, q->answer_protocol); + + r = dns_question_matches_rr(question, rr, DNS_SEARCH_DOMAIN_NAME(q->answer_search_domain)); + if (r < 0) + goto finish; + if (r == 0) + continue; + + r = append_address(reply, rr, ifindex); + if (r < 0) + goto finish; + + if (!canonical) + canonical = dns_resource_record_ref(rr); + + added++; + } + + if (added <= 0) { + r = sd_bus_reply_method_errorf(q->request, BUS_ERROR_NO_SUCH_RR, "'%s' does not have any RR of the requested type", dns_query_string(q)); + goto finish; + } + + r = sd_bus_message_close_container(reply); + if (r < 0) + goto finish; + + /* The key names are not necessarily normalized, make sure that they are when we return them to our bus + * clients. */ + r = dns_name_normalize(dns_resource_key_name(canonical->key), &normalized); + if (r < 0) + goto finish; + + /* Return the precise spelling and uppercasing and CNAME target reported by the server */ + assert(canonical); + r = sd_bus_message_append( + reply, "st", + normalized, + SD_RESOLVED_FLAGS_MAKE(q->answer_protocol, q->answer_family, q->answer_authenticated)); + if (r < 0) + goto finish; + + r = sd_bus_send(q->manager->bus, reply, NULL); + +finish: + if (r < 0) { + log_error_errno(r, "Failed to send hostname reply: %m"); + sd_bus_reply_method_errno(q->request, r, NULL); + } + + dns_query_free(q); +} + +static int check_ifindex_flags(int ifindex, uint64_t *flags, uint64_t ok, sd_bus_error *error) { + assert(flags); + + if (ifindex < 0) + return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid interface index"); + + if (*flags & ~(SD_RESOLVED_PROTOCOLS_ALL|SD_RESOLVED_NO_CNAME|ok)) + return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid flags parameter"); + + if ((*flags & SD_RESOLVED_PROTOCOLS_ALL) == 0) /* If no protocol is enabled, enable all */ + *flags |= SD_RESOLVED_PROTOCOLS_ALL; + + return 0; +} + +static int parse_as_address(sd_bus_message *m, int ifindex, const char *hostname, int family, uint64_t flags) { + _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL; + _cleanup_free_ char *canonical = NULL; + union in_addr_union parsed; + int r, ff, parsed_ifindex = 0; + + /* Check if the hostname is actually already an IP address formatted as string. In that case just parse it, + * let's not attempt to look it up. */ + + r = in_addr_ifindex_from_string_auto(hostname, &ff, &parsed, &parsed_ifindex); + if (r < 0) /* not an address */ + return 0; + + if (family != AF_UNSPEC && ff != family) + return sd_bus_reply_method_errorf(m, BUS_ERROR_NO_SUCH_RR, "The specified address is not of the requested family."); + if (ifindex > 0 && parsed_ifindex > 0 && parsed_ifindex != ifindex) + return sd_bus_reply_method_errorf(m, BUS_ERROR_NO_SUCH_RR, "The specified address interface index does not match requested interface."); + + if (parsed_ifindex > 0) + ifindex = parsed_ifindex; + + r = sd_bus_message_new_method_return(m, &reply); + if (r < 0) + return r; + + r = sd_bus_message_open_container(reply, 'a', "(iiay)"); + if (r < 0) + return r; + + r = sd_bus_message_open_container(reply, 'r', "iiay"); + if (r < 0) + return r; + + r = sd_bus_message_append(reply, "ii", ifindex, ff); + if (r < 0) + return r; + + r = sd_bus_message_append_array(reply, 'y', &parsed, FAMILY_ADDRESS_SIZE(ff)); + if (r < 0) + return r; + + r = sd_bus_message_close_container(reply); + if (r < 0) + return r; + + r = sd_bus_message_close_container(reply); + if (r < 0) + return r; + + /* When an IP address is specified we just return it as canonical name, in order to avoid a DNS + * look-up. However, we reformat it to make sure it's in a truly canonical form (i.e. on IPv6 the inner + * omissions are always done the same way). */ + r = in_addr_ifindex_to_string(ff, &parsed, ifindex, &canonical); + if (r < 0) + return r; + + r = sd_bus_message_append(reply, "st", canonical, + SD_RESOLVED_FLAGS_MAKE(dns_synthesize_protocol(flags), ff, true)); + if (r < 0) + return r; + + return sd_bus_send(sd_bus_message_get_bus(m), reply, NULL); +} + +static int bus_method_resolve_hostname(sd_bus_message *message, void *userdata, sd_bus_error *error) { + _cleanup_(dns_question_unrefp) DnsQuestion *question_idna = NULL, *question_utf8 = NULL; + Manager *m = userdata; + const char *hostname; + int family, ifindex; + uint64_t flags; + DnsQuery *q; + int r; + + assert(message); + assert(m); + + assert_cc(sizeof(int) == sizeof(int32_t)); + + r = sd_bus_message_read(message, "isit", &ifindex, &hostname, &family, &flags); + if (r < 0) + return r; + + if (!IN_SET(family, AF_INET, AF_INET6, AF_UNSPEC)) + return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Unknown address family %i", family); + + r = check_ifindex_flags(ifindex, &flags, SD_RESOLVED_NO_SEARCH, error); + if (r < 0) + return r; + + r = parse_as_address(message, ifindex, hostname, family, flags); + if (r != 0) + return r; + + r = dns_name_is_valid(hostname); + if (r < 0) + return r; + if (r == 0) + return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid hostname '%s'", hostname); + + r = dns_question_new_address(&question_utf8, family, hostname, false); + if (r < 0) + return r; + + r = dns_question_new_address(&question_idna, family, hostname, true); + if (r < 0) + return r; + + r = dns_query_new(m, &q, question_utf8, question_idna, ifindex, flags); + if (r < 0) + return r; + + q->request = sd_bus_message_ref(message); + q->request_family = family; + q->complete = bus_method_resolve_hostname_complete; + q->suppress_unroutable_family = family == AF_UNSPEC; + + r = dns_query_bus_track(q, message); + if (r < 0) + goto fail; + + r = dns_query_go(q); + if (r < 0) + goto fail; + + return 1; + +fail: + dns_query_free(q); + return r; +} + +static void bus_method_resolve_address_complete(DnsQuery *q) { + _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL; + DnsQuestion *question; + DnsResourceRecord *rr; + unsigned added = 0; + int ifindex, r; + + assert(q); + + if (q->state != DNS_TRANSACTION_SUCCESS) { + r = reply_query_state(q); + goto finish; + } + + r = dns_query_process_cname(q); + if (r == -ELOOP) { + r = sd_bus_reply_method_errorf(q->request, BUS_ERROR_CNAME_LOOP, "CNAME loop detected, or CNAME resolving disabled on '%s'", dns_query_string(q)); + goto finish; + } + if (r < 0) + goto finish; + if (r == DNS_QUERY_RESTARTED) /* This was a cname, and the query was restarted. */ + return; + + r = sd_bus_message_new_method_return(q->request, &reply); + if (r < 0) + goto finish; + + r = sd_bus_message_open_container(reply, 'a', "(is)"); + if (r < 0) + goto finish; + + question = dns_query_question_for_protocol(q, q->answer_protocol); + + DNS_ANSWER_FOREACH_IFINDEX(rr, ifindex, q->answer) { + _cleanup_free_ char *normalized = NULL; + + r = dns_question_matches_rr(question, rr, NULL); + if (r < 0) + goto finish; + if (r == 0) + continue; + + r = dns_name_normalize(rr->ptr.name, &normalized); + if (r < 0) + goto finish; + + r = sd_bus_message_append(reply, "(is)", ifindex, normalized); + if (r < 0) + goto finish; + + added++; + } + + if (added <= 0) { + _cleanup_free_ char *ip = NULL; + + (void) in_addr_to_string(q->request_family, &q->request_address, &ip); + r = sd_bus_reply_method_errorf(q->request, BUS_ERROR_NO_SUCH_RR, + "Address '%s' does not have any RR of requested type", strnull(ip)); + goto finish; + } + + r = sd_bus_message_close_container(reply); + if (r < 0) + goto finish; + + r = sd_bus_message_append(reply, "t", SD_RESOLVED_FLAGS_MAKE(q->answer_protocol, q->answer_family, q->answer_authenticated)); + if (r < 0) + goto finish; + + r = sd_bus_send(q->manager->bus, reply, NULL); + +finish: + if (r < 0) { + log_error_errno(r, "Failed to send address reply: %m"); + sd_bus_reply_method_errno(q->request, r, NULL); + } + + dns_query_free(q); +} + +static int bus_method_resolve_address(sd_bus_message *message, void *userdata, sd_bus_error *error) { + _cleanup_(dns_question_unrefp) DnsQuestion *question = NULL; + Manager *m = userdata; + int family, ifindex; + uint64_t flags; + const void *d; + DnsQuery *q; + size_t sz; + int r; + + assert(message); + assert(m); + + assert_cc(sizeof(int) == sizeof(int32_t)); + + r = sd_bus_message_read(message, "ii", &ifindex, &family); + if (r < 0) + return r; + + if (!IN_SET(family, AF_INET, AF_INET6)) + return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Unknown address family %i", family); + + r = sd_bus_message_read_array(message, 'y', &d, &sz); + if (r < 0) + return r; + + if (sz != FAMILY_ADDRESS_SIZE(family)) + return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid address size"); + + r = sd_bus_message_read(message, "t", &flags); + if (r < 0) + return r; + + r = check_ifindex_flags(ifindex, &flags, 0, error); + if (r < 0) + return r; + + r = dns_question_new_reverse(&question, family, d); + if (r < 0) + return r; + + r = dns_query_new(m, &q, question, question, ifindex, flags|SD_RESOLVED_NO_SEARCH); + if (r < 0) + return r; + + q->request = sd_bus_message_ref(message); + q->request_family = family; + memcpy(&q->request_address, d, sz); + q->complete = bus_method_resolve_address_complete; + + r = dns_query_bus_track(q, message); + if (r < 0) + goto fail; + + r = dns_query_go(q); + if (r < 0) + goto fail; + + return 1; + +fail: + dns_query_free(q); + return r; +} + +static int bus_message_append_rr(sd_bus_message *m, DnsResourceRecord *rr, int ifindex) { + int r; + + assert(m); + assert(rr); + + r = sd_bus_message_open_container(m, 'r', "iqqay"); + if (r < 0) + return r; + + r = sd_bus_message_append(m, "iqq", + ifindex, + rr->key->class, + rr->key->type); + if (r < 0) + return r; + + r = dns_resource_record_to_wire_format(rr, false); + if (r < 0) + return r; + + r = sd_bus_message_append_array(m, 'y', rr->wire_format, rr->wire_format_size); + if (r < 0) + return r; + + return sd_bus_message_close_container(m); +} + +static void bus_method_resolve_record_complete(DnsQuery *q) { + _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL; + DnsResourceRecord *rr; + DnsQuestion *question; + unsigned added = 0; + int ifindex; + int r; + + assert(q); + + if (q->state != DNS_TRANSACTION_SUCCESS) { + r = reply_query_state(q); + goto finish; + } + + r = dns_query_process_cname(q); + if (r == -ELOOP) { + r = sd_bus_reply_method_errorf(q->request, BUS_ERROR_CNAME_LOOP, "CNAME loop detected, or CNAME resolving disabled on '%s'", dns_query_string(q)); + goto finish; + } + if (r < 0) + goto finish; + if (r == DNS_QUERY_RESTARTED) /* This was a cname, and the query was restarted. */ + return; + + r = sd_bus_message_new_method_return(q->request, &reply); + if (r < 0) + goto finish; + + r = sd_bus_message_open_container(reply, 'a', "(iqqay)"); + if (r < 0) + goto finish; + + question = dns_query_question_for_protocol(q, q->answer_protocol); + + DNS_ANSWER_FOREACH_IFINDEX(rr, ifindex, q->answer) { + r = dns_question_matches_rr(question, rr, NULL); + if (r < 0) + goto finish; + if (r == 0) + continue; + + r = bus_message_append_rr(reply, rr, ifindex); + if (r < 0) + goto finish; + + added++; + } + + if (added <= 0) { + r = sd_bus_reply_method_errorf(q->request, BUS_ERROR_NO_SUCH_RR, "Name '%s' does not have any RR of the requested type", dns_query_string(q)); + goto finish; + } + + r = sd_bus_message_close_container(reply); + if (r < 0) + goto finish; + + r = sd_bus_message_append(reply, "t", SD_RESOLVED_FLAGS_MAKE(q->answer_protocol, q->answer_family, q->answer_authenticated)); + if (r < 0) + goto finish; + + r = sd_bus_send(q->manager->bus, reply, NULL); + +finish: + if (r < 0) { + log_error_errno(r, "Failed to send record reply: %m"); + sd_bus_reply_method_errno(q->request, r, NULL); + } + + dns_query_free(q); +} + +static int bus_method_resolve_record(sd_bus_message *message, void *userdata, sd_bus_error *error) { + _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL; + _cleanup_(dns_question_unrefp) DnsQuestion *question = NULL; + Manager *m = userdata; + uint16_t class, type; + const char *name; + int r, ifindex; + uint64_t flags; + DnsQuery *q; + + assert(message); + assert(m); + + assert_cc(sizeof(int) == sizeof(int32_t)); + + r = sd_bus_message_read(message, "isqqt", &ifindex, &name, &class, &type, &flags); + if (r < 0) + return r; + + r = dns_name_is_valid(name); + if (r < 0) + return r; + if (r == 0) + return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid name '%s'", name); + + if (!dns_type_is_valid_query(type)) + return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Specified resource record type %" PRIu16 " may not be used in a query.", type); + if (dns_type_is_zone_transer(type)) + return sd_bus_error_setf(error, SD_BUS_ERROR_NOT_SUPPORTED, "Zone transfers not permitted via this programming interface."); + if (dns_type_is_obsolete(type)) + return sd_bus_error_setf(error, SD_BUS_ERROR_NOT_SUPPORTED, "Specified DNS resource record type %" PRIu16 " is obsolete.", type); + + r = check_ifindex_flags(ifindex, &flags, 0, error); + if (r < 0) + return r; + + question = dns_question_new(1); + if (!question) + return -ENOMEM; + + key = dns_resource_key_new(class, type, name); + if (!key) + return -ENOMEM; + + r = dns_question_add(question, key); + if (r < 0) + return r; + + r = dns_query_new(m, &q, question, question, ifindex, flags|SD_RESOLVED_NO_SEARCH); + if (r < 0) + return r; + + /* Let's request that the TTL is fixed up for locally cached entries, after all we return it in the wire format + * blob */ + q->clamp_ttl = true; + + q->request = sd_bus_message_ref(message); + q->complete = bus_method_resolve_record_complete; + + r = dns_query_bus_track(q, message); + if (r < 0) + goto fail; + + r = dns_query_go(q); + if (r < 0) + goto fail; + + return 1; + +fail: + dns_query_free(q); + return r; +} + +static int append_srv(DnsQuery *q, sd_bus_message *reply, DnsResourceRecord *rr) { + _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *canonical = NULL; + _cleanup_free_ char *normalized = NULL; + DnsQuery *aux; + int r; + + assert(q); + assert(reply); + assert(rr); + assert(rr->key); + + if (rr->key->type != DNS_TYPE_SRV) + return 0; + + if ((q->flags & SD_RESOLVED_NO_ADDRESS) == 0) { + /* First, let's see if we could find an appropriate A or AAAA + * record for the SRV record */ + LIST_FOREACH(auxiliary_queries, aux, q->auxiliary_queries) { + DnsResourceRecord *zz; + DnsQuestion *question; + + if (aux->state != DNS_TRANSACTION_SUCCESS) + continue; + if (aux->auxiliary_result != 0) + continue; + + question = dns_query_question_for_protocol(aux, aux->answer_protocol); + + r = dns_name_equal(dns_question_first_name(question), rr->srv.name); + if (r < 0) + return r; + if (r == 0) + continue; + + DNS_ANSWER_FOREACH(zz, aux->answer) { + + r = dns_question_matches_rr(question, zz, NULL); + if (r < 0) + return r; + if (r == 0) + continue; + + canonical = dns_resource_record_ref(zz); + break; + } + + if (canonical) + break; + } + + /* Is there are successful A/AAAA lookup for this SRV RR? If not, don't add it */ + if (!canonical) + return 0; + } + + r = sd_bus_message_open_container(reply, 'r', "qqqsa(iiay)s"); + if (r < 0) + return r; + + r = dns_name_normalize(rr->srv.name, &normalized); + if (r < 0) + return r; + + r = sd_bus_message_append( + reply, + "qqqs", + rr->srv.priority, rr->srv.weight, rr->srv.port, normalized); + if (r < 0) + return r; + + r = sd_bus_message_open_container(reply, 'a', "(iiay)"); + if (r < 0) + return r; + + if ((q->flags & SD_RESOLVED_NO_ADDRESS) == 0) { + LIST_FOREACH(auxiliary_queries, aux, q->auxiliary_queries) { + DnsResourceRecord *zz; + DnsQuestion *question; + int ifindex; + + if (aux->state != DNS_TRANSACTION_SUCCESS) + continue; + if (aux->auxiliary_result != 0) + continue; + + question = dns_query_question_for_protocol(aux, aux->answer_protocol); + + r = dns_name_equal(dns_question_first_name(question), rr->srv.name); + if (r < 0) + return r; + if (r == 0) + continue; + + DNS_ANSWER_FOREACH_IFINDEX(zz, ifindex, aux->answer) { + + r = dns_question_matches_rr(question, zz, NULL); + if (r < 0) + return r; + if (r == 0) + continue; + + r = append_address(reply, zz, ifindex); + if (r < 0) + return r; + } + } + } + + r = sd_bus_message_close_container(reply); + if (r < 0) + return r; + + if (canonical) { + normalized = mfree(normalized); + + r = dns_name_normalize(dns_resource_key_name(canonical->key), &normalized); + if (r < 0) + return r; + } + + /* Note that above we appended the hostname as encoded in the + * SRV, and here the canonical hostname this maps to. */ + r = sd_bus_message_append(reply, "s", normalized); + if (r < 0) + return r; + + r = sd_bus_message_close_container(reply); + if (r < 0) + return r; + + return 1; +} + +static int append_txt(sd_bus_message *reply, DnsResourceRecord *rr) { + DnsTxtItem *i; + int r; + + assert(reply); + assert(rr); + assert(rr->key); + + if (rr->key->type != DNS_TYPE_TXT) + return 0; + + LIST_FOREACH(items, i, rr->txt.items) { + + if (i->length <= 0) + continue; + + r = sd_bus_message_append_array(reply, 'y', i->data, i->length); + if (r < 0) + return r; + } + + return 1; +} + +static void resolve_service_all_complete(DnsQuery *q) { + _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *canonical = NULL; + _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL; + _cleanup_free_ char *name = NULL, *type = NULL, *domain = NULL; + DnsQuestion *question; + DnsResourceRecord *rr; + unsigned added = 0; + DnsQuery *aux; + int r; + + assert(q); + + if (q->block_all_complete > 0) + return; + + if ((q->flags & SD_RESOLVED_NO_ADDRESS) == 0) { + DnsQuery *bad = NULL; + bool have_success = false; + + LIST_FOREACH(auxiliary_queries, aux, q->auxiliary_queries) { + + switch (aux->state) { + + case DNS_TRANSACTION_PENDING: + /* If an auxiliary query is still pending, let's wait */ + return; + + case DNS_TRANSACTION_SUCCESS: + if (aux->auxiliary_result == 0) + have_success = true; + else + bad = aux; + break; + + default: + bad = aux; + break; + } + } + + if (!have_success) { + /* We can only return one error, hence pick the last error we encountered */ + + assert(bad); + + if (bad->state == DNS_TRANSACTION_SUCCESS) { + assert(bad->auxiliary_result != 0); + + if (bad->auxiliary_result == -ELOOP) { + r = sd_bus_reply_method_errorf(q->request, BUS_ERROR_CNAME_LOOP, "CNAME loop detected, or CNAME resolving disabled on '%s'", dns_query_string(bad)); + goto finish; + } + + r = bad->auxiliary_result; + goto finish; + } + + r = reply_query_state(bad); + goto finish; + } + } + + r = sd_bus_message_new_method_return(q->request, &reply); + if (r < 0) + goto finish; + + r = sd_bus_message_open_container(reply, 'a', "(qqqsa(iiay)s)"); + if (r < 0) + goto finish; + + question = dns_query_question_for_protocol(q, q->answer_protocol); + DNS_ANSWER_FOREACH(rr, q->answer) { + r = dns_question_matches_rr(question, rr, NULL); + if (r < 0) + goto finish; + if (r == 0) + continue; + + r = append_srv(q, reply, rr); + if (r < 0) + goto finish; + if (r == 0) /* not an SRV record */ + continue; + + if (!canonical) + canonical = dns_resource_record_ref(rr); + + added++; + } + + if (added <= 0) { + r = sd_bus_reply_method_errorf(q->request, BUS_ERROR_NO_SUCH_RR, "'%s' does not have any RR of the requested type", dns_query_string(q)); + goto finish; + } + + r = sd_bus_message_close_container(reply); + if (r < 0) + goto finish; + + r = sd_bus_message_open_container(reply, 'a', "ay"); + if (r < 0) + goto finish; + + DNS_ANSWER_FOREACH(rr, q->answer) { + r = dns_question_matches_rr(question, rr, NULL); + if (r < 0) + goto finish; + if (r == 0) + continue; + + r = append_txt(reply, rr); + if (r < 0) + goto finish; + } + + r = sd_bus_message_close_container(reply); + if (r < 0) + goto finish; + + assert(canonical); + r = dns_service_split(dns_resource_key_name(canonical->key), &name, &type, &domain); + if (r < 0) + goto finish; + + r = sd_bus_message_append( + reply, + "ssst", + name, type, domain, + SD_RESOLVED_FLAGS_MAKE(q->answer_protocol, q->answer_family, q->answer_authenticated)); + if (r < 0) + goto finish; + + r = sd_bus_send(q->manager->bus, reply, NULL); + +finish: + if (r < 0) { + log_error_errno(r, "Failed to send service reply: %m"); + sd_bus_reply_method_errno(q->request, r, NULL); + } + + dns_query_free(q); +} + +static void resolve_service_hostname_complete(DnsQuery *q) { + int r; + + assert(q); + assert(q->auxiliary_for); + + if (q->state != DNS_TRANSACTION_SUCCESS) { + resolve_service_all_complete(q->auxiliary_for); + return; + } + + r = dns_query_process_cname(q); + if (r == DNS_QUERY_RESTARTED) /* This was a cname, and the query was restarted. */ + return; + + /* This auxiliary lookup is finished or failed, let's see if all are finished now. */ + q->auxiliary_result = r; + resolve_service_all_complete(q->auxiliary_for); +} + +static int resolve_service_hostname(DnsQuery *q, DnsResourceRecord *rr, int ifindex) { + _cleanup_(dns_question_unrefp) DnsQuestion *question = NULL; + DnsQuery *aux; + int r; + + assert(q); + assert(rr); + assert(rr->key); + assert(rr->key->type == DNS_TYPE_SRV); + + /* OK, we found an SRV record for the service. Let's resolve + * the hostname included in it */ + + r = dns_question_new_address(&question, q->request_family, rr->srv.name, false); + if (r < 0) + return r; + + r = dns_query_new(q->manager, &aux, question, question, ifindex, q->flags|SD_RESOLVED_NO_SEARCH); + if (r < 0) + return r; + + aux->request_family = q->request_family; + aux->complete = resolve_service_hostname_complete; + + r = dns_query_make_auxiliary(aux, q); + if (r == -EAGAIN) { + /* Too many auxiliary lookups? If so, don't complain, + * let's just not add this one, we already have more + * than enough */ + + dns_query_free(aux); + return 0; + } + if (r < 0) + goto fail; + + /* Note that auxiliary queries do not track the original bus + * client, only the primary request does that. */ + + r = dns_query_go(aux); + if (r < 0) + goto fail; + + return 1; + +fail: + dns_query_free(aux); + return r; +} + +static void bus_method_resolve_service_complete(DnsQuery *q) { + bool has_root_domain = false; + DnsResourceRecord *rr; + DnsQuestion *question; + unsigned found = 0; + int ifindex, r; + + assert(q); + + if (q->state != DNS_TRANSACTION_SUCCESS) { + r = reply_query_state(q); + goto finish; + } + + r = dns_query_process_cname(q); + if (r == -ELOOP) { + r = sd_bus_reply_method_errorf(q->request, BUS_ERROR_CNAME_LOOP, "CNAME loop detected, or CNAME resolving disabled on '%s'", dns_query_string(q)); + goto finish; + } + if (r < 0) + goto finish; + if (r == DNS_QUERY_RESTARTED) /* This was a cname, and the query was restarted. */ + return; + + question = dns_query_question_for_protocol(q, q->answer_protocol); + + DNS_ANSWER_FOREACH_IFINDEX(rr, ifindex, q->answer) { + r = dns_question_matches_rr(question, rr, NULL); + if (r < 0) + goto finish; + if (r == 0) + continue; + + if (rr->key->type != DNS_TYPE_SRV) + continue; + + if (dns_name_is_root(rr->srv.name)) { + has_root_domain = true; + continue; + } + + if ((q->flags & SD_RESOLVED_NO_ADDRESS) == 0) { + q->block_all_complete++; + r = resolve_service_hostname(q, rr, ifindex); + q->block_all_complete--; + + if (r < 0) + goto finish; + } + + found++; + } + + if (has_root_domain && found <= 0) { + /* If there's exactly one SRV RR and it uses + * the root domain as host name, then the + * service is explicitly not offered on the + * domain. Report this as a recognizable + * error. See RFC 2782, Section "Usage + * Rules". */ + r = sd_bus_reply_method_errorf(q->request, BUS_ERROR_NO_SUCH_SERVICE, "'%s' does not provide the requested service", dns_query_string(q)); + goto finish; + } + + if (found <= 0) { + r = sd_bus_reply_method_errorf(q->request, BUS_ERROR_NO_SUCH_RR, "'%s' does not have any RR of the requested type", dns_query_string(q)); + goto finish; + } + + /* Maybe we are already finished? check now... */ + resolve_service_all_complete(q); + return; + +finish: + if (r < 0) { + log_error_errno(r, "Failed to send service reply: %m"); + sd_bus_reply_method_errno(q->request, r, NULL); + } + + dns_query_free(q); +} + +static int bus_method_resolve_service(sd_bus_message *message, void *userdata, sd_bus_error *error) { + _cleanup_(dns_question_unrefp) DnsQuestion *question_idna = NULL, *question_utf8 = NULL; + const char *name, *type, *domain; + Manager *m = userdata; + int family, ifindex; + uint64_t flags; + DnsQuery *q; + int r; + + assert(message); + assert(m); + + assert_cc(sizeof(int) == sizeof(int32_t)); + + r = sd_bus_message_read(message, "isssit", &ifindex, &name, &type, &domain, &family, &flags); + if (r < 0) + return r; + + if (!IN_SET(family, AF_INET, AF_INET6, AF_UNSPEC)) + return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Unknown address family %i", family); + + if (isempty(name)) + name = NULL; + else if (!dns_service_name_is_valid(name)) + return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid service name '%s'", name); + + if (isempty(type)) + type = NULL; + else if (!dns_srv_type_is_valid(type)) + return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid SRV service type '%s'", type); + + r = dns_name_is_valid(domain); + if (r < 0) + return r; + if (r == 0) + return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid domain '%s'", domain); + + if (name && !type) + return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Service name cannot be specified without service type."); + + r = check_ifindex_flags(ifindex, &flags, SD_RESOLVED_NO_TXT|SD_RESOLVED_NO_ADDRESS, error); + if (r < 0) + return r; + + r = dns_question_new_service(&question_utf8, name, type, domain, !(flags & SD_RESOLVED_NO_TXT), false); + if (r < 0) + return r; + + r = dns_question_new_service(&question_idna, name, type, domain, !(flags & SD_RESOLVED_NO_TXT), true); + if (r < 0) + return r; + + r = dns_query_new(m, &q, question_utf8, question_idna, ifindex, flags|SD_RESOLVED_NO_SEARCH); + if (r < 0) + return r; + + q->request = sd_bus_message_ref(message); + q->request_family = family; + q->complete = bus_method_resolve_service_complete; + + r = dns_query_bus_track(q, message); + if (r < 0) + goto fail; + + r = dns_query_go(q); + if (r < 0) + goto fail; + + return 1; + +fail: + dns_query_free(q); + return r; +} + +int bus_dns_server_append(sd_bus_message *reply, DnsServer *s, bool with_ifindex) { + int r; + + assert(reply); + assert(s); + + r = sd_bus_message_open_container(reply, 'r', with_ifindex ? "iiay" : "iay"); + if (r < 0) + return r; + + if (with_ifindex) { + r = sd_bus_message_append(reply, "i", dns_server_ifindex(s)); + if (r < 0) + return r; + } + + r = sd_bus_message_append(reply, "i", s->family); + if (r < 0) + return r; + + r = sd_bus_message_append_array(reply, 'y', &s->address, FAMILY_ADDRESS_SIZE(s->family)); + if (r < 0) + return r; + + return sd_bus_message_close_container(reply); +} + +static int bus_property_get_dns_servers( + sd_bus *bus, + const char *path, + const char *interface, + const char *property, + sd_bus_message *reply, + void *userdata, + sd_bus_error *error) { + + Manager *m = userdata; + unsigned c = 0; + DnsServer *s; + Iterator i; + Link *l; + int r; + + assert(reply); + assert(m); + + r = sd_bus_message_open_container(reply, 'a', "(iiay)"); + if (r < 0) + return r; + + LIST_FOREACH(servers, s, m->dns_servers) { + r = bus_dns_server_append(reply, s, true); + if (r < 0) + return r; + + c++; + } + + HASHMAP_FOREACH(l, m->links, i) { + LIST_FOREACH(servers, s, l->dns_servers) { + r = bus_dns_server_append(reply, s, true); + if (r < 0) + return r; + c++; + } + } + + if (c == 0) { + LIST_FOREACH(servers, s, m->fallback_dns_servers) { + r = bus_dns_server_append(reply, s, true); + if (r < 0) + return r; + } + } + + return sd_bus_message_close_container(reply); +} + +static int bus_property_get_domains( + sd_bus *bus, + const char *path, + const char *interface, + const char *property, + sd_bus_message *reply, + void *userdata, + sd_bus_error *error) { + + Manager *m = userdata; + DnsSearchDomain *d; + Iterator i; + Link *l; + int r; + + assert(reply); + assert(m); + + r = sd_bus_message_open_container(reply, 'a', "(isb)"); + if (r < 0) + return r; + + LIST_FOREACH(domains, d, m->search_domains) { + r = sd_bus_message_append(reply, "(isb)", 0, d->name, d->route_only); + if (r < 0) + return r; + } + + HASHMAP_FOREACH(l, m->links, i) { + LIST_FOREACH(domains, d, l->search_domains) { + r = sd_bus_message_append(reply, "(isb)", l->ifindex, d->name, d->route_only); + if (r < 0) + return r; + } + } + + return sd_bus_message_close_container(reply); +} + +static int bus_property_get_transaction_statistics( + sd_bus *bus, + const char *path, + const char *interface, + const char *property, + sd_bus_message *reply, + void *userdata, + sd_bus_error *error) { + + Manager *m = userdata; + + assert(reply); + assert(m); + + return sd_bus_message_append(reply, "(tt)", + (uint64_t) hashmap_size(m->dns_transactions), + (uint64_t) m->n_transactions_total); +} + +static int bus_property_get_cache_statistics( + sd_bus *bus, + const char *path, + const char *interface, + const char *property, + sd_bus_message *reply, + void *userdata, + sd_bus_error *error) { + + uint64_t size = 0, hit = 0, miss = 0; + Manager *m = userdata; + DnsScope *s; + + assert(reply); + assert(m); + + LIST_FOREACH(scopes, s, m->dns_scopes) { + size += dns_cache_size(&s->cache); + hit += s->cache.n_hit; + miss += s->cache.n_miss; + } + + return sd_bus_message_append(reply, "(ttt)", size, hit, miss); +} + +static int bus_property_get_dnssec_statistics( + sd_bus *bus, + const char *path, + const char *interface, + const char *property, + sd_bus_message *reply, + void *userdata, + sd_bus_error *error) { + + Manager *m = userdata; + + assert(reply); + assert(m); + + return sd_bus_message_append(reply, "(tttt)", + (uint64_t) m->n_dnssec_verdict[DNSSEC_SECURE], + (uint64_t) m->n_dnssec_verdict[DNSSEC_INSECURE], + (uint64_t) m->n_dnssec_verdict[DNSSEC_BOGUS], + (uint64_t) m->n_dnssec_verdict[DNSSEC_INDETERMINATE]); +} + +static int bus_property_get_dnssec_supported( + sd_bus *bus, + const char *path, + const char *interface, + const char *property, + sd_bus_message *reply, + void *userdata, + sd_bus_error *error) { + + Manager *m = userdata; + + assert(reply); + assert(m); + + return sd_bus_message_append(reply, "b", manager_dnssec_supported(m)); +} + +static int bus_property_get_ntas( + sd_bus *bus, + const char *path, + const char *interface, + const char *property, + sd_bus_message *reply, + void *userdata, + sd_bus_error *error) { + + Manager *m = userdata; + const char *domain; + Iterator i; + int r; + + assert(reply); + assert(m); + + r = sd_bus_message_open_container(reply, 'a', "s"); + if (r < 0) + return r; + + SET_FOREACH(domain, m->trust_anchor.negative_by_name, i) { + r = sd_bus_message_append(reply, "s", domain); + if (r < 0) + return r; + } + + return sd_bus_message_close_container(reply); +} + +static int bus_method_reset_statistics(sd_bus_message *message, void *userdata, sd_bus_error *error) { + Manager *m = userdata; + DnsScope *s; + + assert(message); + assert(m); + + LIST_FOREACH(scopes, s, m->dns_scopes) + s->cache.n_hit = s->cache.n_miss = 0; + + m->n_transactions_total = 0; + zero(m->n_dnssec_verdict); + + return sd_bus_reply_method_return(message, NULL); +} + +static int get_any_link(Manager *m, int ifindex, Link **ret, sd_bus_error *error) { + Link *l; + + assert(m); + assert(ret); + + if (ifindex <= 0) + return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid interface index"); + + l = hashmap_get(m->links, INT_TO_PTR(ifindex)); + if (!l) + return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_LINK, "Link %i not known", ifindex); + + *ret = l; + return 0; +} + +static int call_link_method(Manager *m, sd_bus_message *message, sd_bus_message_handler_t handler, sd_bus_error *error) { + int ifindex, r; + Link *l; + + assert(m); + assert(message); + assert(handler); + + assert_cc(sizeof(int) == sizeof(int32_t)); + r = sd_bus_message_read(message, "i", &ifindex); + if (r < 0) + return r; + + r = get_any_link(m, ifindex, &l, error); + if (r < 0) + return r; + + return handler(message, l, error); +} + +static int bus_method_set_link_dns_servers(sd_bus_message *message, void *userdata, sd_bus_error *error) { + return call_link_method(userdata, message, bus_link_method_set_dns_servers, error); +} + +static int bus_method_set_link_domains(sd_bus_message *message, void *userdata, sd_bus_error *error) { + return call_link_method(userdata, message, bus_link_method_set_domains, error); +} + +static int bus_method_set_link_llmnr(sd_bus_message *message, void *userdata, sd_bus_error *error) { + return call_link_method(userdata, message, bus_link_method_set_llmnr, error); +} + +static int bus_method_set_link_mdns(sd_bus_message *message, void *userdata, sd_bus_error *error) { + return call_link_method(userdata, message, bus_link_method_set_mdns, error); +} + +static int bus_method_set_link_dnssec(sd_bus_message *message, void *userdata, sd_bus_error *error) { + return call_link_method(userdata, message, bus_link_method_set_dnssec, error); +} + +static int bus_method_set_link_dnssec_negative_trust_anchors(sd_bus_message *message, void *userdata, sd_bus_error *error) { + return call_link_method(userdata, message, bus_link_method_set_dnssec_negative_trust_anchors, error); +} + +static int bus_method_revert_link(sd_bus_message *message, void *userdata, sd_bus_error *error) { + return call_link_method(userdata, message, bus_link_method_revert, error); +} + +static int bus_method_get_link(sd_bus_message *message, void *userdata, sd_bus_error *error) { + _cleanup_free_ char *p = NULL; + Manager *m = userdata; + int r, ifindex; + Link *l; + + assert(message); + assert(m); + + assert_cc(sizeof(int) == sizeof(int32_t)); + r = sd_bus_message_read(message, "i", &ifindex); + if (r < 0) + return r; + + r = get_any_link(m, ifindex, &l, error); + if (r < 0) + return r; + + p = link_bus_path(l); + if (!p) + return -ENOMEM; + + return sd_bus_reply_method_return(message, "o", p); +} + +static int bus_method_flush_caches(sd_bus_message *message, void *userdata, sd_bus_error *error) { + Manager *m = userdata; + + assert(message); + assert(m); + + manager_flush_caches(m); + + return sd_bus_reply_method_return(message, NULL); +} + +static const sd_bus_vtable resolve_vtable[] = { + SD_BUS_VTABLE_START(0), + SD_BUS_PROPERTY("LLMNRHostname", "s", NULL, offsetof(Manager, llmnr_hostname), 0), + SD_BUS_PROPERTY("DNS", "a(iiay)", bus_property_get_dns_servers, 0, 0), + SD_BUS_PROPERTY("Domains", "a(isb)", bus_property_get_domains, 0, 0), + SD_BUS_PROPERTY("TransactionStatistics", "(tt)", bus_property_get_transaction_statistics, 0, 0), + SD_BUS_PROPERTY("CacheStatistics", "(ttt)", bus_property_get_cache_statistics, 0, 0), + SD_BUS_PROPERTY("DNSSECStatistics", "(tttt)", bus_property_get_dnssec_statistics, 0, 0), + SD_BUS_PROPERTY("DNSSECSupported", "b", bus_property_get_dnssec_supported, 0, 0), + SD_BUS_PROPERTY("DNSSECNegativeTrustAnchors", "as", bus_property_get_ntas, 0, 0), + + SD_BUS_METHOD("ResolveHostname", "isit", "a(iiay)st", bus_method_resolve_hostname, SD_BUS_VTABLE_UNPRIVILEGED), + SD_BUS_METHOD("ResolveAddress", "iiayt", "a(is)t", bus_method_resolve_address, SD_BUS_VTABLE_UNPRIVILEGED), + SD_BUS_METHOD("ResolveRecord", "isqqt", "a(iqqay)t", bus_method_resolve_record, SD_BUS_VTABLE_UNPRIVILEGED), + SD_BUS_METHOD("ResolveService", "isssit", "a(qqqsa(iiay)s)aayssst", bus_method_resolve_service, SD_BUS_VTABLE_UNPRIVILEGED), + SD_BUS_METHOD("ResetStatistics", NULL, NULL, bus_method_reset_statistics, 0), + SD_BUS_METHOD("FlushCaches", NULL, NULL, bus_method_flush_caches, 0), + SD_BUS_METHOD("GetLink", "i", "o", bus_method_get_link, SD_BUS_VTABLE_UNPRIVILEGED), + SD_BUS_METHOD("SetLinkDNS", "ia(iay)", NULL, bus_method_set_link_dns_servers, 0), + SD_BUS_METHOD("SetLinkDomains", "ia(sb)", NULL, bus_method_set_link_domains, 0), + SD_BUS_METHOD("SetLinkLLMNR", "is", NULL, bus_method_set_link_llmnr, 0), + SD_BUS_METHOD("SetLinkMulticastDNS", "is", NULL, bus_method_set_link_mdns, 0), + SD_BUS_METHOD("SetLinkDNSSEC", "is", NULL, bus_method_set_link_dnssec, 0), + SD_BUS_METHOD("SetLinkDNSSECNegativeTrustAnchors", "ias", NULL, bus_method_set_link_dnssec_negative_trust_anchors, 0), + SD_BUS_METHOD("RevertLink", "i", NULL, bus_method_revert_link, 0), + + SD_BUS_VTABLE_END, +}; + +static int on_bus_retry(sd_event_source *s, usec_t usec, void *userdata) { + Manager *m = userdata; + + assert(s); + assert(m); + + m->bus_retry_event_source = sd_event_source_unref(m->bus_retry_event_source); + + manager_connect_bus(m); + return 0; +} + +static int match_prepare_for_sleep(sd_bus_message *message, void *userdata, sd_bus_error *ret_error) { + Manager *m = userdata; + int b, r; + + assert(message); + assert(m); + + r = sd_bus_message_read(message, "b", &b); + if (r < 0) { + log_debug_errno(r, "Failed to parse PrepareForSleep signal: %m"); + return 0; + } + + if (b) + return 0; + + log_debug("Coming back from suspend, verifying all RRs..."); + + manager_verify_all(m); + return 0; +} + +int manager_connect_bus(Manager *m) { + int r; + + assert(m); + + if (m->bus) + return 0; + + r = sd_bus_default_system(&m->bus); + if (r < 0) { + /* We failed to connect? Yuck, we must be in early + * boot. Let's try in 5s again. As soon as we have + * kdbus we can stop doing this... */ + + log_debug_errno(r, "Failed to connect to bus, trying again in 5s: %m"); + + r = sd_event_add_time(m->event, &m->bus_retry_event_source, CLOCK_MONOTONIC, now(CLOCK_MONOTONIC) + 5*USEC_PER_SEC, 0, on_bus_retry, m); + if (r < 0) + return log_error_errno(r, "Failed to install bus reconnect time event: %m"); + + (void) sd_event_source_set_description(m->bus_retry_event_source, "bus-retry"); + return 0; + } + + r = sd_bus_add_object_vtable(m->bus, NULL, "/org/freedesktop/resolve1", "org.freedesktop.resolve1.Manager", resolve_vtable, m); + if (r < 0) + return log_error_errno(r, "Failed to register object: %m"); + + r = sd_bus_add_fallback_vtable(m->bus, NULL, "/org/freedesktop/resolve1/link", "org.freedesktop.resolve1.Link", link_vtable, link_object_find, m); + if (r < 0) + return log_error_errno(r, "Failed to register link objects: %m"); + + r = sd_bus_add_node_enumerator(m->bus, NULL, "/org/freedesktop/resolve1/link", link_node_enumerator, m); + if (r < 0) + return log_error_errno(r, "Failed to register link enumerator: %m"); + + r = sd_bus_request_name(m->bus, "org.freedesktop.resolve1", 0); + if (r < 0) + return log_error_errno(r, "Failed to register name: %m"); + + r = sd_bus_attach_event(m->bus, m->event, 0); + if (r < 0) + return log_error_errno(r, "Failed to attach bus to event loop: %m"); + + r = sd_bus_add_match(m->bus, &m->prepare_for_sleep_slot, + "type='signal'," + "sender='org.freedesktop.login1'," + "interface='org.freedesktop.login1.Manager'," + "member='PrepareForSleep'," + "path='/org/freedesktop/login1'", + match_prepare_for_sleep, + m); + if (r < 0) + log_error_errno(r, "Failed to add match for PrepareForSleep: %m"); + + return 0; +} diff --git a/src/grp-resolve/systemd-resolved/resolved-bus.h b/src/grp-resolve/systemd-resolved/resolved-bus.h new file mode 100644 index 0000000000..f49e1337d2 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-bus.h @@ -0,0 +1,25 @@ +#pragma once + +/*** + This file is part of systemd. + + Copyright 2014 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include "resolved-manager.h" + +int manager_connect_bus(Manager *m); +int bus_dns_server_append(sd_bus_message *reply, DnsServer *s, bool with_ifindex); diff --git a/src/grp-resolve/systemd-resolved/resolved-conf.c b/src/grp-resolve/systemd-resolved/resolved-conf.c new file mode 100644 index 0000000000..48aa2da331 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-conf.c @@ -0,0 +1,252 @@ +/*** + This file is part of systemd. + + Copyright 2014 Tom Gundersen <teg@jklm.no> + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. + ***/ + +#include "systemd-basic/alloc-util.h" +#include "systemd-basic/def.h" +#include "systemd-basic/extract-word.h" +#include "systemd-basic/parse-util.h" +#include "systemd-basic/string-table.h" +#include "systemd-basic/string-util.h" +#include "systemd-shared/conf-parser.h" + +#include "resolved-conf.h" + +DEFINE_CONFIG_PARSE_ENUM(config_parse_dns_stub_listener_mode, dns_stub_listener_mode, DnsStubListenerMode, "Failed to parse DNS stub listener mode setting"); + +static const char* const dns_stub_listener_mode_table[_DNS_STUB_LISTENER_MODE_MAX] = { + [DNS_STUB_LISTENER_NO] = "no", + [DNS_STUB_LISTENER_UDP] = "udp", + [DNS_STUB_LISTENER_TCP] = "tcp", + [DNS_STUB_LISTENER_YES] = "yes", +}; +DEFINE_STRING_TABLE_LOOKUP_WITH_BOOLEAN(dns_stub_listener_mode, DnsStubListenerMode, DNS_STUB_LISTENER_YES); + +int manager_add_dns_server_by_string(Manager *m, DnsServerType type, const char *word) { + union in_addr_union address; + int family, r, ifindex = 0; + DnsServer *s; + + assert(m); + assert(word); + + r = in_addr_ifindex_from_string_auto(word, &family, &address, &ifindex); + if (r < 0) + return r; + + /* Silently filter out 0.0.0.0 and 127.0.0.53 (our own stub DNS listener) */ + if (!dns_server_address_valid(family, &address)) + return 0; + + /* Filter out duplicates */ + s = dns_server_find(manager_get_first_dns_server(m, type), family, &address, ifindex); + if (s) { + /* + * Drop the marker. This is used to find the servers + * that ceased to exist, see + * manager_mark_dns_servers() and + * manager_flush_marked_dns_servers(). + */ + dns_server_move_back_and_unmark(s); + return 0; + } + + return dns_server_new(m, NULL, type, NULL, family, &address, ifindex); +} + +int manager_parse_dns_server_string_and_warn(Manager *m, DnsServerType type, const char *string) { + int r; + + assert(m); + assert(string); + + for (;;) { + _cleanup_free_ char *word = NULL; + + r = extract_first_word(&string, &word, NULL, 0); + if (r < 0) + return r; + if (r == 0) + break; + + r = manager_add_dns_server_by_string(m, type, word); + if (r < 0) + log_warning_errno(r, "Failed to add DNS server address '%s', ignoring: %m", word); + } + + return 0; +} + +int manager_add_search_domain_by_string(Manager *m, const char *domain) { + DnsSearchDomain *d; + bool route_only; + int r; + + assert(m); + assert(domain); + + route_only = *domain == '~'; + if (route_only) + domain++; + + if (dns_name_is_root(domain) || streq(domain, "*")) { + route_only = true; + domain = "."; + } + + r = dns_search_domain_find(m->search_domains, domain, &d); + if (r < 0) + return r; + if (r > 0) + dns_search_domain_move_back_and_unmark(d); + else { + r = dns_search_domain_new(m, &d, DNS_SEARCH_DOMAIN_SYSTEM, NULL, domain); + if (r < 0) + return r; + } + + d->route_only = route_only; + return 0; +} + +int manager_parse_search_domains_and_warn(Manager *m, const char *string) { + int r; + + assert(m); + assert(string); + + for (;;) { + _cleanup_free_ char *word = NULL; + + r = extract_first_word(&string, &word, NULL, EXTRACT_QUOTES); + if (r < 0) + return r; + if (r == 0) + break; + + r = manager_add_search_domain_by_string(m, word); + if (r < 0) + log_warning_errno(r, "Failed to add search domain '%s', ignoring: %m", word); + } + + return 0; +} + +int config_parse_dns_servers( + const char *unit, + const char *filename, + unsigned line, + const char *section, + unsigned section_line, + const char *lvalue, + int ltype, + const char *rvalue, + void *data, + void *userdata) { + + Manager *m = userdata; + int r; + + assert(filename); + assert(lvalue); + assert(rvalue); + assert(m); + + if (isempty(rvalue)) + /* Empty assignment means clear the list */ + dns_server_unlink_all(manager_get_first_dns_server(m, ltype)); + else { + /* Otherwise, add to the list */ + r = manager_parse_dns_server_string_and_warn(m, ltype, rvalue); + if (r < 0) { + log_syntax(unit, LOG_ERR, filename, line, r, "Failed to parse DNS server string '%s'. Ignoring.", rvalue); + return 0; + } + } + + /* If we have a manual setting, then we stop reading + * /etc/resolv.conf */ + if (ltype == DNS_SERVER_SYSTEM) + m->read_resolv_conf = false; + if (ltype == DNS_SERVER_FALLBACK) + m->need_builtin_fallbacks = false; + + return 0; +} + +int config_parse_search_domains( + const char *unit, + const char *filename, + unsigned line, + const char *section, + unsigned section_line, + const char *lvalue, + int ltype, + const char *rvalue, + void *data, + void *userdata) { + + Manager *m = userdata; + int r; + + assert(filename); + assert(lvalue); + assert(rvalue); + assert(m); + + if (isempty(rvalue)) + /* Empty assignment means clear the list */ + dns_search_domain_unlink_all(m->search_domains); + else { + /* Otherwise, add to the list */ + r = manager_parse_search_domains_and_warn(m, rvalue); + if (r < 0) { + log_syntax(unit, LOG_ERR, filename, line, r, "Failed to parse search domains string '%s'. Ignoring.", rvalue); + return 0; + } + } + + /* If we have a manual setting, then we stop reading + * /etc/resolv.conf */ + m->read_resolv_conf = false; + + return 0; +} + +int manager_parse_config_file(Manager *m) { + int r; + + assert(m); + + r = config_parse_many_nulstr(PKGSYSCONFDIR "/resolved.conf", + CONF_PATHS_NULSTR("systemd/resolved.conf.d"), + "Resolve\0", + config_item_perf_lookup, resolved_gperf_lookup, + false, m); + if (r < 0) + return r; + + if (m->need_builtin_fallbacks) { + r = manager_parse_dns_server_string_and_warn(m, DNS_SERVER_FALLBACK, DNS_SERVERS); + if (r < 0) + return r; + } + + return 0; + +} diff --git a/src/grp-resolve/systemd-resolved/resolved-conf.h b/src/grp-resolve/systemd-resolved/resolved-conf.h new file mode 100644 index 0000000000..e8cd8e1af3 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-conf.h @@ -0,0 +1,51 @@ +#pragma once + +/*** + This file is part of systemd. + + Copyright 2014 Tom Gundersen <teg@jklm.no> + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +typedef enum DnsStubListenerMode DnsStubListenerMode; + +enum DnsStubListenerMode { + DNS_STUB_LISTENER_NO, + DNS_STUB_LISTENER_UDP, + DNS_STUB_LISTENER_TCP, + DNS_STUB_LISTENER_YES, + _DNS_STUB_LISTENER_MODE_MAX, + _DNS_STUB_LISTENER_MODE_INVALID = -1 +}; + +#include "resolved-dns-server.h" +#include "resolved-manager.h" + +int manager_parse_config_file(Manager *m); + +int manager_add_search_domain_by_string(Manager *m, const char *domain); +int manager_parse_search_domains_and_warn(Manager *m, const char *string); + +int manager_add_dns_server_by_string(Manager *m, DnsServerType type, const char *word); +int manager_parse_dns_server_string_and_warn(Manager *m, DnsServerType type, const char *string); + +const struct ConfigPerfItem* resolved_gperf_lookup(const char *key, GPERF_LEN_TYPE length); + +int config_parse_dns_servers(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata); +int config_parse_search_domains(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata); +int config_parse_dns_stub_listener_mode(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata); + +const char* dns_stub_listener_mode_to_string(DnsStubListenerMode p) _const_; +DnsStubListenerMode dns_stub_listener_mode_from_string(const char *s) _pure_; diff --git a/src/grp-resolve/systemd-resolved/resolved-dns-cache.c b/src/grp-resolve/systemd-resolved/resolved-dns-cache.c new file mode 100644 index 0000000000..1f8811c5de --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-dns-cache.c @@ -0,0 +1,1065 @@ +/*** + This file is part of systemd. + + Copyright 2014 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include <net/if.h> + +#include "basic-dns/resolved-dns-answer.h" +#include "basic-dns/resolved-dns-packet.h" +#include "systemd-basic/af-list.h" +#include "systemd-basic/alloc-util.h" +#include "systemd-basic/string-util.h" +#include "systemd-shared/dns-domain.h" + +#include "resolved-dns-cache.h" + +/* Never cache more than 4K entries. RFC 1536, Section 5 suggests to + * leave DNS caches unbounded, but that's crazy. */ +#define CACHE_MAX 4096 + +/* We never keep any item longer than 2h in our cache */ +#define CACHE_TTL_MAX_USEC (2 * USEC_PER_HOUR) + +typedef enum DnsCacheItemType DnsCacheItemType; +typedef struct DnsCacheItem DnsCacheItem; + +enum DnsCacheItemType { + DNS_CACHE_POSITIVE, + DNS_CACHE_NODATA, + DNS_CACHE_NXDOMAIN, +}; + +struct DnsCacheItem { + DnsCacheItemType type; + DnsResourceKey *key; + DnsResourceRecord *rr; + + usec_t until; + bool authenticated:1; + bool shared_owner:1; + + int ifindex; + int owner_family; + union in_addr_union owner_address; + + unsigned prioq_idx; + LIST_FIELDS(DnsCacheItem, by_key); +}; + +static void dns_cache_item_free(DnsCacheItem *i) { + if (!i) + return; + + dns_resource_record_unref(i->rr); + dns_resource_key_unref(i->key); + free(i); +} + +DEFINE_TRIVIAL_CLEANUP_FUNC(DnsCacheItem*, dns_cache_item_free); + +static void dns_cache_item_unlink_and_free(DnsCache *c, DnsCacheItem *i) { + DnsCacheItem *first; + + assert(c); + + if (!i) + return; + + first = hashmap_get(c->by_key, i->key); + LIST_REMOVE(by_key, first, i); + + if (first) + assert_se(hashmap_replace(c->by_key, first->key, first) >= 0); + else + hashmap_remove(c->by_key, i->key); + + prioq_remove(c->by_expiry, i, &i->prioq_idx); + + dns_cache_item_free(i); +} + +static bool dns_cache_remove_by_rr(DnsCache *c, DnsResourceRecord *rr) { + DnsCacheItem *first, *i; + int r; + + first = hashmap_get(c->by_key, rr->key); + LIST_FOREACH(by_key, i, first) { + r = dns_resource_record_equal(i->rr, rr); + if (r < 0) + return r; + if (r > 0) { + dns_cache_item_unlink_and_free(c, i); + return true; + } + } + + return false; +} + +static bool dns_cache_remove_by_key(DnsCache *c, DnsResourceKey *key) { + DnsCacheItem *first, *i, *n; + + assert(c); + assert(key); + + first = hashmap_remove(c->by_key, key); + if (!first) + return false; + + LIST_FOREACH_SAFE(by_key, i, n, first) { + prioq_remove(c->by_expiry, i, &i->prioq_idx); + dns_cache_item_free(i); + } + + return true; +} + +void dns_cache_flush(DnsCache *c) { + DnsResourceKey *key; + + assert(c); + + while ((key = hashmap_first_key(c->by_key))) + dns_cache_remove_by_key(c, key); + + assert(hashmap_size(c->by_key) == 0); + assert(prioq_size(c->by_expiry) == 0); + + c->by_key = hashmap_free(c->by_key); + c->by_expiry = prioq_free(c->by_expiry); +} + +static void dns_cache_make_space(DnsCache *c, unsigned add) { + assert(c); + + if (add <= 0) + return; + + /* Makes space for n new entries. Note that we actually allow + * the cache to grow beyond CACHE_MAX, but only when we shall + * add more RRs to the cache than CACHE_MAX at once. In that + * case the cache will be emptied completely otherwise. */ + + for (;;) { + _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL; + DnsCacheItem *i; + + if (prioq_size(c->by_expiry) <= 0) + break; + + if (prioq_size(c->by_expiry) + add < CACHE_MAX) + break; + + i = prioq_peek(c->by_expiry); + assert(i); + + /* Take an extra reference to the key so that it + * doesn't go away in the middle of the remove call */ + key = dns_resource_key_ref(i->key); + dns_cache_remove_by_key(c, key); + } +} + +void dns_cache_prune(DnsCache *c) { + usec_t t = 0; + + assert(c); + + /* Remove all entries that are past their TTL */ + + for (;;) { + DnsCacheItem *i; + char key_str[DNS_RESOURCE_KEY_STRING_MAX]; + + i = prioq_peek(c->by_expiry); + if (!i) + break; + + if (t <= 0) + t = now(clock_boottime_or_monotonic()); + + if (i->until > t) + break; + + /* Depending whether this is an mDNS shared entry + * either remove only this one RR or the whole RRset */ + log_debug("Removing %scache entry for %s (expired "USEC_FMT"s ago)", + i->shared_owner ? "shared " : "", + dns_resource_key_to_string(i->key, key_str, sizeof key_str), + (t - i->until) / USEC_PER_SEC); + + if (i->shared_owner) + dns_cache_item_unlink_and_free(c, i); + else { + _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL; + + /* Take an extra reference to the key so that it + * doesn't go away in the middle of the remove call */ + key = dns_resource_key_ref(i->key); + dns_cache_remove_by_key(c, key); + } + } +} + +static int dns_cache_item_prioq_compare_func(const void *a, const void *b) { + const DnsCacheItem *x = a, *y = b; + + if (x->until < y->until) + return -1; + if (x->until > y->until) + return 1; + return 0; +} + +static int dns_cache_init(DnsCache *c) { + int r; + + assert(c); + + r = prioq_ensure_allocated(&c->by_expiry, dns_cache_item_prioq_compare_func); + if (r < 0) + return r; + + r = hashmap_ensure_allocated(&c->by_key, &dns_resource_key_hash_ops); + if (r < 0) + return r; + + return r; +} + +static int dns_cache_link_item(DnsCache *c, DnsCacheItem *i) { + DnsCacheItem *first; + int r; + + assert(c); + assert(i); + + r = prioq_put(c->by_expiry, i, &i->prioq_idx); + if (r < 0) + return r; + + first = hashmap_get(c->by_key, i->key); + if (first) { + _cleanup_(dns_resource_key_unrefp) DnsResourceKey *k = NULL; + + /* Keep a reference to the original key, while we manipulate the list. */ + k = dns_resource_key_ref(first->key); + + /* Now, try to reduce the number of keys we keep */ + dns_resource_key_reduce(&first->key, &i->key); + + if (first->rr) + dns_resource_key_reduce(&first->rr->key, &i->key); + if (i->rr) + dns_resource_key_reduce(&i->rr->key, &i->key); + + LIST_PREPEND(by_key, first, i); + assert_se(hashmap_replace(c->by_key, first->key, first) >= 0); + } else { + r = hashmap_put(c->by_key, i->key, i); + if (r < 0) { + prioq_remove(c->by_expiry, i, &i->prioq_idx); + return r; + } + } + + return 0; +} + +static DnsCacheItem* dns_cache_get(DnsCache *c, DnsResourceRecord *rr) { + DnsCacheItem *i; + + assert(c); + assert(rr); + + LIST_FOREACH(by_key, i, hashmap_get(c->by_key, rr->key)) + if (i->rr && dns_resource_record_equal(i->rr, rr) > 0) + return i; + + return NULL; +} + +static usec_t calculate_until(DnsResourceRecord *rr, uint32_t nsec_ttl, usec_t timestamp, bool use_soa_minimum) { + uint32_t ttl; + usec_t u; + + assert(rr); + + ttl = MIN(rr->ttl, nsec_ttl); + if (rr->key->type == DNS_TYPE_SOA && use_soa_minimum) { + /* If this is a SOA RR, and it is requested, clamp to + * the SOA's minimum field. This is used when we do + * negative caching, to determine the TTL for the + * negative caching entry. See RFC 2308, Section + * 5. */ + + if (ttl > rr->soa.minimum) + ttl = rr->soa.minimum; + } + + u = ttl * USEC_PER_SEC; + if (u > CACHE_TTL_MAX_USEC) + u = CACHE_TTL_MAX_USEC; + + if (rr->expiry != USEC_INFINITY) { + usec_t left; + + /* Make use of the DNSSEC RRSIG expiry info, if we + * have it */ + + left = LESS_BY(rr->expiry, now(CLOCK_REALTIME)); + if (u > left) + u = left; + } + + return timestamp + u; +} + +static void dns_cache_item_update_positive( + DnsCache *c, + DnsCacheItem *i, + DnsResourceRecord *rr, + bool authenticated, + bool shared_owner, + usec_t timestamp, + int ifindex, + int owner_family, + const union in_addr_union *owner_address) { + + assert(c); + assert(i); + assert(rr); + assert(owner_address); + + i->type = DNS_CACHE_POSITIVE; + + if (!i->by_key_prev) + /* We are the first item in the list, we need to + * update the key used in the hashmap */ + + assert_se(hashmap_replace(c->by_key, rr->key, i) >= 0); + + dns_resource_record_ref(rr); + dns_resource_record_unref(i->rr); + i->rr = rr; + + dns_resource_key_unref(i->key); + i->key = dns_resource_key_ref(rr->key); + + i->until = calculate_until(rr, (uint32_t) -1, timestamp, false); + i->authenticated = authenticated; + i->shared_owner = shared_owner; + + i->ifindex = ifindex; + + i->owner_family = owner_family; + i->owner_address = *owner_address; + + prioq_reshuffle(c->by_expiry, i, &i->prioq_idx); +} + +static int dns_cache_put_positive( + DnsCache *c, + DnsResourceRecord *rr, + bool authenticated, + bool shared_owner, + usec_t timestamp, + int ifindex, + int owner_family, + const union in_addr_union *owner_address) { + + _cleanup_(dns_cache_item_freep) DnsCacheItem *i = NULL; + DnsCacheItem *existing; + char key_str[DNS_RESOURCE_KEY_STRING_MAX], ifname[IF_NAMESIZE]; + int r, k; + + assert(c); + assert(rr); + assert(owner_address); + + /* Never cache pseudo RRs */ + if (dns_class_is_pseudo(rr->key->class)) + return 0; + if (dns_type_is_pseudo(rr->key->type)) + return 0; + + /* New TTL is 0? Delete this specific entry... */ + if (rr->ttl <= 0) { + k = dns_cache_remove_by_rr(c, rr); + log_debug("%s: %s", + k > 0 ? "Removed zero TTL entry from cache" : "Not caching zero TTL cache entry", + dns_resource_key_to_string(rr->key, key_str, sizeof key_str)); + return 0; + } + + /* Entry exists already? Update TTL, timestamp and owner*/ + existing = dns_cache_get(c, rr); + if (existing) { + dns_cache_item_update_positive( + c, + existing, + rr, + authenticated, + shared_owner, + timestamp, + ifindex, + owner_family, + owner_address); + return 0; + } + + /* Otherwise, add the new RR */ + r = dns_cache_init(c); + if (r < 0) + return r; + + dns_cache_make_space(c, 1); + + i = new0(DnsCacheItem, 1); + if (!i) + return -ENOMEM; + + i->type = DNS_CACHE_POSITIVE; + i->key = dns_resource_key_ref(rr->key); + i->rr = dns_resource_record_ref(rr); + i->until = calculate_until(rr, (uint32_t) -1, timestamp, false); + i->authenticated = authenticated; + i->shared_owner = shared_owner; + i->ifindex = ifindex; + i->owner_family = owner_family; + i->owner_address = *owner_address; + i->prioq_idx = PRIOQ_IDX_NULL; + + r = dns_cache_link_item(c, i); + if (r < 0) + return r; + + if (log_get_max_level() >= LOG_DEBUG) { + _cleanup_free_ char *t = NULL; + + (void) in_addr_to_string(i->owner_family, &i->owner_address, &t); + + log_debug("Added positive %s%s cache entry for %s "USEC_FMT"s on %s/%s/%s", + i->authenticated ? "authenticated" : "unauthenticated", + i->shared_owner ? " shared" : "", + dns_resource_key_to_string(i->key, key_str, sizeof key_str), + (i->until - timestamp) / USEC_PER_SEC, + i->ifindex == 0 ? "*" : strna(if_indextoname(i->ifindex, ifname)), + af_to_name_short(i->owner_family), + strna(t)); + } + + i = NULL; + return 0; +} + +static int dns_cache_put_negative( + DnsCache *c, + DnsResourceKey *key, + int rcode, + bool authenticated, + uint32_t nsec_ttl, + usec_t timestamp, + DnsResourceRecord *soa, + int owner_family, + const union in_addr_union *owner_address) { + + _cleanup_(dns_cache_item_freep) DnsCacheItem *i = NULL; + char key_str[DNS_RESOURCE_KEY_STRING_MAX]; + int r; + + assert(c); + assert(key); + assert(soa); + assert(owner_address); + + /* Never cache pseudo RR keys. DNS_TYPE_ANY is particularly + * important to filter out as we use this as a pseudo-type for + * NXDOMAIN entries */ + if (dns_class_is_pseudo(key->class)) + return 0; + if (dns_type_is_pseudo(key->type)) + return 0; + + if (nsec_ttl <= 0 || soa->soa.minimum <= 0 || soa->ttl <= 0) { + log_debug("Not caching negative entry with zero SOA/NSEC/NSEC3 TTL: %s", + dns_resource_key_to_string(key, key_str, sizeof key_str)); + return 0; + } + + if (!IN_SET(rcode, DNS_RCODE_SUCCESS, DNS_RCODE_NXDOMAIN)) + return 0; + + r = dns_cache_init(c); + if (r < 0) + return r; + + dns_cache_make_space(c, 1); + + i = new0(DnsCacheItem, 1); + if (!i) + return -ENOMEM; + + i->type = rcode == DNS_RCODE_SUCCESS ? DNS_CACHE_NODATA : DNS_CACHE_NXDOMAIN; + i->until = calculate_until(soa, nsec_ttl, timestamp, true); + i->authenticated = authenticated; + i->owner_family = owner_family; + i->owner_address = *owner_address; + i->prioq_idx = PRIOQ_IDX_NULL; + + if (i->type == DNS_CACHE_NXDOMAIN) { + /* NXDOMAIN entries should apply equally to all types, so we use ANY as + * a pseudo type for this purpose here. */ + i->key = dns_resource_key_new(key->class, DNS_TYPE_ANY, dns_resource_key_name(key)); + if (!i->key) + return -ENOMEM; + + /* Make sure to remove any previous entry for this + * specific ANY key. (For non-ANY keys the cache data + * is already cleared by the caller.) Note that we + * don't bother removing positive or NODATA cache + * items in this case, because it would either be slow + * or require explicit indexing by name */ + dns_cache_remove_by_key(c, key); + } else + i->key = dns_resource_key_ref(key); + + r = dns_cache_link_item(c, i); + if (r < 0) + return r; + + log_debug("Added %s cache entry for %s "USEC_FMT"s", + i->type == DNS_CACHE_NODATA ? "NODATA" : "NXDOMAIN", + dns_resource_key_to_string(i->key, key_str, sizeof key_str), + (i->until - timestamp) / USEC_PER_SEC); + + i = NULL; + return 0; +} + +static void dns_cache_remove_previous( + DnsCache *c, + DnsResourceKey *key, + DnsAnswer *answer) { + + DnsResourceRecord *rr; + DnsAnswerFlags flags; + + assert(c); + + /* First, if we were passed a key (i.e. on LLMNR/DNS, but + * not on mDNS), delete all matching old RRs, so that we only + * keep complete by_key in place. */ + if (key) + dns_cache_remove_by_key(c, key); + + /* Second, flush all entries matching the answer, unless this + * is an RR that is explicitly marked to be "shared" between + * peers (i.e. mDNS RRs without the flush-cache bit set). */ + DNS_ANSWER_FOREACH_FLAGS(rr, flags, answer) { + if ((flags & DNS_ANSWER_CACHEABLE) == 0) + continue; + + if (flags & DNS_ANSWER_SHARED_OWNER) + continue; + + dns_cache_remove_by_key(c, rr->key); + } +} + +static bool rr_eligible(DnsResourceRecord *rr) { + assert(rr); + + /* When we see an NSEC/NSEC3 RR, we'll only cache it if it is from the lower zone, not the upper zone, since + * that's where the interesting bits are (with exception of DS RRs). Of course, this way we cannot derive DS + * existence from any cached NSEC/NSEC3, but that should be fine. */ + + switch (rr->key->type) { + + case DNS_TYPE_NSEC: + return !bitmap_isset(rr->nsec.types, DNS_TYPE_NS) || + bitmap_isset(rr->nsec.types, DNS_TYPE_SOA); + + case DNS_TYPE_NSEC3: + return !bitmap_isset(rr->nsec3.types, DNS_TYPE_NS) || + bitmap_isset(rr->nsec3.types, DNS_TYPE_SOA); + + default: + return true; + } +} + +int dns_cache_put( + DnsCache *c, + DnsResourceKey *key, + int rcode, + DnsAnswer *answer, + bool authenticated, + uint32_t nsec_ttl, + usec_t timestamp, + int owner_family, + const union in_addr_union *owner_address) { + + DnsResourceRecord *soa = NULL, *rr; + DnsAnswerFlags flags; + unsigned cache_keys; + int r, ifindex; + + assert(c); + assert(owner_address); + + dns_cache_remove_previous(c, key, answer); + + /* We only care for positive replies and NXDOMAINs, on all + * other replies we will simply flush the respective entries, + * and that's it */ + if (!IN_SET(rcode, DNS_RCODE_SUCCESS, DNS_RCODE_NXDOMAIN)) + return 0; + + if (dns_answer_size(answer) <= 0) { + char key_str[DNS_RESOURCE_KEY_STRING_MAX]; + + log_debug("Not caching negative entry without a SOA record: %s", + dns_resource_key_to_string(key, key_str, sizeof key_str)); + return 0; + } + + cache_keys = dns_answer_size(answer); + if (key) + cache_keys++; + + /* Make some space for our new entries */ + dns_cache_make_space(c, cache_keys); + + if (timestamp <= 0) + timestamp = now(clock_boottime_or_monotonic()); + + /* Second, add in positive entries for all contained RRs */ + DNS_ANSWER_FOREACH_FULL(rr, ifindex, flags, answer) { + if ((flags & DNS_ANSWER_CACHEABLE) == 0) + continue; + + r = rr_eligible(rr); + if (r < 0) + return r; + if (r == 0) + continue; + + r = dns_cache_put_positive( + c, + rr, + flags & DNS_ANSWER_AUTHENTICATED, + flags & DNS_ANSWER_SHARED_OWNER, + timestamp, + ifindex, + owner_family, owner_address); + if (r < 0) + goto fail; + } + + if (!key) /* mDNS doesn't know negative caching, really */ + return 0; + + /* Third, add in negative entries if the key has no RR */ + r = dns_answer_match_key(answer, key, NULL); + if (r < 0) + goto fail; + if (r > 0) + return 0; + + /* But not if it has a matching CNAME/DNAME (the negative + * caching will be done on the canonical name, not on the + * alias) */ + r = dns_answer_find_cname_or_dname(answer, key, NULL, NULL); + if (r < 0) + goto fail; + if (r > 0) + return 0; + + /* See https://tools.ietf.org/html/rfc2308, which say that a + * matching SOA record in the packet is used to enable + * negative caching. */ + r = dns_answer_find_soa(answer, key, &soa, &flags); + if (r < 0) + goto fail; + if (r == 0) + return 0; + + /* Refuse using the SOA data if it is unsigned, but the key is + * signed */ + if (authenticated && (flags & DNS_ANSWER_AUTHENTICATED) == 0) + return 0; + + r = dns_cache_put_negative( + c, + key, + rcode, + authenticated, + nsec_ttl, + timestamp, + soa, + owner_family, owner_address); + if (r < 0) + goto fail; + + return 0; + +fail: + /* Adding all RRs failed. Let's clean up what we already + * added, just in case */ + + if (key) + dns_cache_remove_by_key(c, key); + + DNS_ANSWER_FOREACH_FLAGS(rr, flags, answer) { + if ((flags & DNS_ANSWER_CACHEABLE) == 0) + continue; + + dns_cache_remove_by_key(c, rr->key); + } + + return r; +} + +static DnsCacheItem *dns_cache_get_by_key_follow_cname_dname_nsec(DnsCache *c, DnsResourceKey *k) { + DnsCacheItem *i; + const char *n; + int r; + + assert(c); + assert(k); + + /* If we hit some OOM error, or suchlike, we don't care too + * much, after all this is just a cache */ + + i = hashmap_get(c->by_key, k); + if (i) + return i; + + n = dns_resource_key_name(k); + + /* Check if we have an NXDOMAIN cache item for the name, notice that we use + * the pseudo-type ANY for NXDOMAIN cache items. */ + i = hashmap_get(c->by_key, &DNS_RESOURCE_KEY_CONST(k->class, DNS_TYPE_ANY, n)); + if (i && i->type == DNS_CACHE_NXDOMAIN) + return i; + + if (dns_type_may_redirect(k->type)) { + /* Check if we have a CNAME record instead */ + i = hashmap_get(c->by_key, &DNS_RESOURCE_KEY_CONST(k->class, DNS_TYPE_CNAME, n)); + if (i) + return i; + + /* OK, let's look for cached DNAME records. */ + for (;;) { + if (isempty(n)) + return NULL; + + i = hashmap_get(c->by_key, &DNS_RESOURCE_KEY_CONST(k->class, DNS_TYPE_DNAME, n)); + if (i) + return i; + + /* Jump one label ahead */ + r = dns_name_parent(&n); + if (r <= 0) + return NULL; + } + } + + if (k->type != DNS_TYPE_NSEC) { + /* Check if we have an NSEC record instead for the name. */ + i = hashmap_get(c->by_key, &DNS_RESOURCE_KEY_CONST(k->class, DNS_TYPE_NSEC, n)); + if (i) + return i; + } + + return NULL; +} + +int dns_cache_lookup(DnsCache *c, DnsResourceKey *key, bool clamp_ttl, int *rcode, DnsAnswer **ret, bool *authenticated) { + _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL; + char key_str[DNS_RESOURCE_KEY_STRING_MAX]; + unsigned n = 0; + int r; + bool nxdomain = false; + DnsCacheItem *j, *first, *nsec = NULL; + bool have_authenticated = false, have_non_authenticated = false; + usec_t current; + + assert(c); + assert(key); + assert(rcode); + assert(ret); + assert(authenticated); + + if (key->type == DNS_TYPE_ANY || key->class == DNS_CLASS_ANY) { + /* If we have ANY lookups we don't use the cache, so + * that the caller refreshes via the network. */ + + log_debug("Ignoring cache for ANY lookup: %s", + dns_resource_key_to_string(key, key_str, sizeof key_str)); + + c->n_miss++; + + *ret = NULL; + *rcode = DNS_RCODE_SUCCESS; + return 0; + } + + first = dns_cache_get_by_key_follow_cname_dname_nsec(c, key); + if (!first) { + /* If one question cannot be answered we need to refresh */ + + log_debug("Cache miss for %s", + dns_resource_key_to_string(key, key_str, sizeof key_str)); + + c->n_miss++; + + *ret = NULL; + *rcode = DNS_RCODE_SUCCESS; + return 0; + } + + LIST_FOREACH(by_key, j, first) { + if (j->rr) { + if (j->rr->key->type == DNS_TYPE_NSEC) + nsec = j; + + n++; + } else if (j->type == DNS_CACHE_NXDOMAIN) + nxdomain = true; + + if (j->authenticated) + have_authenticated = true; + else + have_non_authenticated = true; + } + + if (nsec && !IN_SET(key->type, DNS_TYPE_NSEC, DNS_TYPE_DS)) { + /* Note that we won't derive information for DS RRs from an NSEC, because we only cache NSEC RRs from + * the lower-zone of a zone cut, but the DS RRs are on the upper zone. */ + + log_debug("NSEC NODATA cache hit for %s", + dns_resource_key_to_string(key, key_str, sizeof key_str)); + + /* We only found an NSEC record that matches our name. + * If it says the type doesn't exist report + * NODATA. Otherwise report a cache miss. */ + + *ret = NULL; + *rcode = DNS_RCODE_SUCCESS; + *authenticated = nsec->authenticated; + + if (!bitmap_isset(nsec->rr->nsec.types, key->type) && + !bitmap_isset(nsec->rr->nsec.types, DNS_TYPE_CNAME) && + !bitmap_isset(nsec->rr->nsec.types, DNS_TYPE_DNAME)) { + c->n_hit++; + return 1; + } + + c->n_miss++; + return 0; + } + + log_debug("%s cache hit for %s", + n > 0 ? "Positive" : + nxdomain ? "NXDOMAIN" : "NODATA", + dns_resource_key_to_string(key, key_str, sizeof key_str)); + + if (n <= 0) { + c->n_hit++; + + *ret = NULL; + *rcode = nxdomain ? DNS_RCODE_NXDOMAIN : DNS_RCODE_SUCCESS; + *authenticated = have_authenticated && !have_non_authenticated; + return 1; + } + + answer = dns_answer_new(n); + if (!answer) + return -ENOMEM; + + if (clamp_ttl) + current = now(clock_boottime_or_monotonic()); + + LIST_FOREACH(by_key, j, first) { + _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL; + + if (!j->rr) + continue; + + if (clamp_ttl) { + rr = dns_resource_record_ref(j->rr); + + r = dns_resource_record_clamp_ttl(&rr, LESS_BY(j->until, current) / USEC_PER_SEC); + if (r < 0) + return r; + } + + r = dns_answer_add(answer, rr ?: j->rr, j->ifindex, j->authenticated ? DNS_ANSWER_AUTHENTICATED : 0); + if (r < 0) + return r; + } + + c->n_hit++; + + *ret = answer; + *rcode = DNS_RCODE_SUCCESS; + *authenticated = have_authenticated && !have_non_authenticated; + answer = NULL; + + return n; +} + +int dns_cache_check_conflicts(DnsCache *cache, DnsResourceRecord *rr, int owner_family, const union in_addr_union *owner_address) { + DnsCacheItem *i, *first; + bool same_owner = true; + + assert(cache); + assert(rr); + + dns_cache_prune(cache); + + /* See if there's a cache entry for the same key. If there + * isn't there's no conflict */ + first = hashmap_get(cache->by_key, rr->key); + if (!first) + return 0; + + /* See if the RR key is owned by the same owner, if so, there + * isn't a conflict either */ + LIST_FOREACH(by_key, i, first) { + if (i->owner_family != owner_family || + !in_addr_equal(owner_family, &i->owner_address, owner_address)) { + same_owner = false; + break; + } + } + if (same_owner) + return 0; + + /* See if there's the exact same RR in the cache. If yes, then + * there's no conflict. */ + if (dns_cache_get(cache, rr)) + return 0; + + /* There's a conflict */ + return 1; +} + +int dns_cache_export_shared_to_packet(DnsCache *cache, DnsPacket *p) { + unsigned ancount = 0; + Iterator iterator; + DnsCacheItem *i; + int r; + + assert(cache); + assert(p); + + HASHMAP_FOREACH(i, cache->by_key, iterator) { + DnsCacheItem *j; + + LIST_FOREACH(by_key, j, i) { + if (!j->rr) + continue; + + if (!j->shared_owner) + continue; + + r = dns_packet_append_rr(p, j->rr, NULL, NULL); + if (r == -EMSGSIZE && p->protocol == DNS_PROTOCOL_MDNS) { + /* For mDNS, if we're unable to stuff all known answers into the given packet, + * allocate a new one, push the RR into that one and link it to the current one. + */ + + DNS_PACKET_HEADER(p)->ancount = htobe16(ancount); + ancount = 0; + + r = dns_packet_new_query(&p->more, p->protocol, 0, true); + if (r < 0) + return r; + + /* continue with new packet */ + p = p->more; + r = dns_packet_append_rr(p, j->rr, NULL, NULL); + } + + if (r < 0) + return r; + + ancount++; + } + } + + DNS_PACKET_HEADER(p)->ancount = htobe16(ancount); + + return 0; +} + +void dns_cache_dump(DnsCache *cache, FILE *f) { + Iterator iterator; + DnsCacheItem *i; + + if (!cache) + return; + + if (!f) + f = stdout; + + HASHMAP_FOREACH(i, cache->by_key, iterator) { + DnsCacheItem *j; + + LIST_FOREACH(by_key, j, i) { + + fputc('\t', f); + + if (j->rr) { + const char *t; + t = dns_resource_record_to_string(j->rr); + if (!t) { + log_oom(); + continue; + } + + fputs(t, f); + fputc('\n', f); + } else { + char key_str[DNS_RESOURCE_KEY_STRING_MAX]; + + fputs(dns_resource_key_to_string(j->key, key_str, sizeof key_str), f); + fputs(" -- ", f); + fputs(j->type == DNS_CACHE_NODATA ? "NODATA" : "NXDOMAIN", f); + fputc('\n', f); + } + } + } +} + +bool dns_cache_is_empty(DnsCache *cache) { + if (!cache) + return true; + + return hashmap_isempty(cache->by_key); +} + +unsigned dns_cache_size(DnsCache *cache) { + if (!cache) + return 0; + + return hashmap_size(cache->by_key); +} diff --git a/src/grp-resolve/systemd-resolved/resolved-dns-cache.h b/src/grp-resolve/systemd-resolved/resolved-dns-cache.h new file mode 100644 index 0000000000..c2b6a987b9 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-dns-cache.h @@ -0,0 +1,52 @@ +#pragma once + +/*** + This file is part of systemd. + + Copyright 2014 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include "systemd-basic/hashmap.h" +#include "systemd-basic/list.h" +#include "systemd-basic/prioq.h" +#include "systemd-basic/time-util.h" + +typedef struct DnsCache { + Hashmap *by_key; + Prioq *by_expiry; + unsigned n_hit; + unsigned n_miss; +} DnsCache; + +#include "basic-dns/resolved-dns-answer.h" +#include "basic-dns/resolved-dns-packet.h" +#include "basic-dns/resolved-dns-question.h" +#include "basic-dns/resolved-dns-rr.h" + +void dns_cache_flush(DnsCache *c); +void dns_cache_prune(DnsCache *c); + +int dns_cache_put(DnsCache *c, DnsResourceKey *key, int rcode, DnsAnswer *answer, bool authenticated, uint32_t nsec_ttl, usec_t timestamp, int owner_family, const union in_addr_union *owner_address); +int dns_cache_lookup(DnsCache *c, DnsResourceKey *key, bool clamp_ttl, int *rcode, DnsAnswer **answer, bool *authenticated); + +int dns_cache_check_conflicts(DnsCache *cache, DnsResourceRecord *rr, int owner_family, const union in_addr_union *owner_address); + +void dns_cache_dump(DnsCache *cache, FILE *f); +bool dns_cache_is_empty(DnsCache *cache); + +unsigned dns_cache_size(DnsCache *cache); + +int dns_cache_export_shared_to_packet(DnsCache *cache, DnsPacket *p); diff --git a/src/grp-resolve/systemd-resolved/resolved-dns-query.c b/src/grp-resolve/systemd-resolved/resolved-dns-query.c new file mode 100644 index 0000000000..2193dc5bcf --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-dns-query.c @@ -0,0 +1,1118 @@ +/*** + This file is part of systemd. + + Copyright 2014 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include "basic-dns/dns-type.h" +#include "sd-netlink/local-addresses.h" +#include "systemd-basic/alloc-util.h" +#include "systemd-basic/hostname-util.h" +#include "systemd-basic/string-util.h" +#include "systemd-shared/dns-domain.h" + +#include "resolved-dns-query.h" +#include "resolved-dns-synthesize.h" +#include "resolved-etc-hosts.h" + +/* How long to wait for the query in total */ +#define QUERY_TIMEOUT_USEC (30 * USEC_PER_SEC) + +#define CNAME_MAX 8 +#define QUERIES_MAX 2048 +#define AUXILIARY_QUERIES_MAX 64 + +static int dns_query_candidate_new(DnsQueryCandidate **ret, DnsQuery *q, DnsScope *s) { + DnsQueryCandidate *c; + + assert(ret); + assert(q); + assert(s); + + c = new0(DnsQueryCandidate, 1); + if (!c) + return -ENOMEM; + + c->query = q; + c->scope = s; + + LIST_PREPEND(candidates_by_query, q->candidates, c); + LIST_PREPEND(candidates_by_scope, s->query_candidates, c); + + *ret = c; + return 0; +} + +static void dns_query_candidate_stop(DnsQueryCandidate *c) { + DnsTransaction *t; + + assert(c); + + while ((t = set_steal_first(c->transactions))) { + set_remove(t->notify_query_candidates, c); + set_remove(t->notify_query_candidates_done, c); + dns_transaction_gc(t); + } +} + +DnsQueryCandidate* dns_query_candidate_free(DnsQueryCandidate *c) { + + if (!c) + return NULL; + + dns_query_candidate_stop(c); + + set_free(c->transactions); + dns_search_domain_unref(c->search_domain); + + if (c->query) + LIST_REMOVE(candidates_by_query, c->query->candidates, c); + + if (c->scope) + LIST_REMOVE(candidates_by_scope, c->scope->query_candidates, c); + + return mfree(c); +} + +static int dns_query_candidate_next_search_domain(DnsQueryCandidate *c) { + DnsSearchDomain *next = NULL; + + assert(c); + + if (c->search_domain && c->search_domain->linked) + next = c->search_domain->domains_next; + else + next = dns_scope_get_search_domains(c->scope); + + for (;;) { + if (!next) /* We hit the end of the list */ + return 0; + + if (!next->route_only) + break; + + /* Skip over route-only domains */ + next = next->domains_next; + } + + dns_search_domain_unref(c->search_domain); + c->search_domain = dns_search_domain_ref(next); + + return 1; +} + +static int dns_query_candidate_add_transaction(DnsQueryCandidate *c, DnsResourceKey *key) { + DnsTransaction *t; + int r; + + assert(c); + assert(key); + + t = dns_scope_find_transaction(c->scope, key, true); + if (!t) { + r = dns_transaction_new(&t, c->scope, key); + if (r < 0) + return r; + } else { + if (set_contains(c->transactions, t)) + return 0; + } + + r = set_ensure_allocated(&c->transactions, NULL); + if (r < 0) + goto gc; + + r = set_ensure_allocated(&t->notify_query_candidates, NULL); + if (r < 0) + goto gc; + + r = set_ensure_allocated(&t->notify_query_candidates_done, NULL); + if (r < 0) + goto gc; + + r = set_put(t->notify_query_candidates, c); + if (r < 0) + goto gc; + + r = set_put(c->transactions, t); + if (r < 0) { + (void) set_remove(t->notify_query_candidates, c); + goto gc; + } + + t->clamp_ttl = c->query->clamp_ttl; + return 1; + +gc: + dns_transaction_gc(t); + return r; +} + +static int dns_query_candidate_go(DnsQueryCandidate *c) { + DnsTransaction *t; + Iterator i; + int r; + unsigned n = 0; + + assert(c); + + /* Start the transactions that are not started yet */ + SET_FOREACH(t, c->transactions, i) { + if (t->state != DNS_TRANSACTION_NULL) + continue; + + r = dns_transaction_go(t); + if (r < 0) + return r; + + n++; + } + + /* If there was nothing to start, then let's proceed immediately */ + if (n == 0) + dns_query_candidate_notify(c); + + return 0; +} + +static DnsTransactionState dns_query_candidate_state(DnsQueryCandidate *c) { + DnsTransactionState state = DNS_TRANSACTION_NO_SERVERS; + DnsTransaction *t; + Iterator i; + + assert(c); + + if (c->error_code != 0) + return DNS_TRANSACTION_ERRNO; + + SET_FOREACH(t, c->transactions, i) { + + switch (t->state) { + + case DNS_TRANSACTION_NULL: + /* If there's a NULL transaction pending, then + * this means not all transactions where + * started yet, and we were called from within + * the stackframe that is supposed to start + * remaining transactions. In this case, + * simply claim the candidate is pending. */ + + case DNS_TRANSACTION_PENDING: + case DNS_TRANSACTION_VALIDATING: + /* If there's one transaction currently in + * VALIDATING state, then this means there's + * also one in PENDING state, hence we can + * return PENDING immediately. */ + return DNS_TRANSACTION_PENDING; + + case DNS_TRANSACTION_SUCCESS: + state = t->state; + break; + + default: + if (state != DNS_TRANSACTION_SUCCESS) + state = t->state; + + break; + } + } + + return state; +} + +static bool dns_query_candidate_is_routable(DnsQueryCandidate *c, uint16_t type) { + int family; + + assert(c); + + /* Checks whether the specified RR type matches an address family that is routable on the link(s) the scope of + * this candidate belongs to. Specifically, whether there's a routable IPv4 address on it if we query an A RR, + * or a routable IPv6 address if we query an AAAA RR. */ + + if (!c->query->suppress_unroutable_family) + return true; + + if (c->scope->protocol != DNS_PROTOCOL_DNS) + return true; + + family = dns_type_to_af(type); + if (family < 0) + return true; + + if (c->scope->link) + return link_relevant(c->scope->link, family, false); + else + return manager_routable(c->scope->manager, family); +} + +static int dns_query_candidate_setup_transactions(DnsQueryCandidate *c) { + DnsQuestion *question; + DnsResourceKey *key; + int n = 0, r; + + assert(c); + + dns_query_candidate_stop(c); + + question = dns_query_question_for_protocol(c->query, c->scope->protocol); + + /* Create one transaction per question key */ + DNS_QUESTION_FOREACH(key, question) { + _cleanup_(dns_resource_key_unrefp) DnsResourceKey *new_key = NULL; + DnsResourceKey *qkey; + + if (!dns_query_candidate_is_routable(c, key->type)) + continue; + + if (c->search_domain) { + r = dns_resource_key_new_append_suffix(&new_key, key, c->search_domain->name); + if (r < 0) + goto fail; + + qkey = new_key; + } else + qkey = key; + + if (!dns_scope_good_key(c->scope, qkey)) + continue; + + r = dns_query_candidate_add_transaction(c, qkey); + if (r < 0) + goto fail; + + n++; + } + + return n; + +fail: + dns_query_candidate_stop(c); + return r; +} + +void dns_query_candidate_notify(DnsQueryCandidate *c) { + DnsTransactionState state; + int r; + + assert(c); + + state = dns_query_candidate_state(c); + + if (DNS_TRANSACTION_IS_LIVE(state)) + return; + + if (state != DNS_TRANSACTION_SUCCESS && c->search_domain) { + + r = dns_query_candidate_next_search_domain(c); + if (r < 0) + goto fail; + + if (r > 0) { + /* OK, there's another search domain to try, let's do so. */ + + r = dns_query_candidate_setup_transactions(c); + if (r < 0) + goto fail; + + if (r > 0) { + /* New transactions where queued. Start them and wait */ + + r = dns_query_candidate_go(c); + if (r < 0) + goto fail; + + return; + } + } + + } + + dns_query_ready(c->query); + return; + +fail: + log_warning_errno(r, "Failed to follow search domains: %m"); + c->error_code = r; + dns_query_ready(c->query); +} + +static void dns_query_stop(DnsQuery *q) { + DnsQueryCandidate *c; + + assert(q); + + q->timeout_event_source = sd_event_source_unref(q->timeout_event_source); + + LIST_FOREACH(candidates_by_query, c, q->candidates) + dns_query_candidate_stop(c); +} + +static void dns_query_free_candidates(DnsQuery *q) { + assert(q); + + while (q->candidates) + dns_query_candidate_free(q->candidates); +} + +static void dns_query_reset_answer(DnsQuery *q) { + assert(q); + + q->answer = dns_answer_unref(q->answer); + q->answer_rcode = 0; + q->answer_dnssec_result = _DNSSEC_RESULT_INVALID; + q->answer_errno = 0; + q->answer_authenticated = false; + q->answer_protocol = _DNS_PROTOCOL_INVALID; + q->answer_family = AF_UNSPEC; + q->answer_search_domain = dns_search_domain_unref(q->answer_search_domain); +} + +DnsQuery *dns_query_free(DnsQuery *q) { + if (!q) + return NULL; + + while (q->auxiliary_queries) + dns_query_free(q->auxiliary_queries); + + if (q->auxiliary_for) { + assert(q->auxiliary_for->n_auxiliary_queries > 0); + q->auxiliary_for->n_auxiliary_queries--; + LIST_REMOVE(auxiliary_queries, q->auxiliary_for->auxiliary_queries, q); + } + + dns_query_free_candidates(q); + + dns_question_unref(q->question_idna); + dns_question_unref(q->question_utf8); + + dns_query_reset_answer(q); + + sd_bus_message_unref(q->request); + sd_bus_track_unref(q->bus_track); + + dns_packet_unref(q->request_dns_packet); + + if (q->request_dns_stream) { + /* Detach the stream from our query, in case something else keeps a reference to it. */ + q->request_dns_stream->complete = NULL; + q->request_dns_stream->on_packet = NULL; + q->request_dns_stream->query = NULL; + dns_stream_unref(q->request_dns_stream); + } + + free(q->request_address_string); + + if (q->manager) { + LIST_REMOVE(queries, q->manager->dns_queries, q); + q->manager->n_dns_queries--; + } + + return mfree(q); +} + +int dns_query_new( + Manager *m, + DnsQuery **ret, + DnsQuestion *question_utf8, + DnsQuestion *question_idna, + int ifindex, + uint64_t flags) { + + _cleanup_(dns_query_freep) DnsQuery *q = NULL; + DnsResourceKey *key; + bool good = false; + int r; + char key_str[DNS_RESOURCE_KEY_STRING_MAX]; + + assert(m); + + if (dns_question_size(question_utf8) > 0) { + r = dns_question_is_valid_for_query(question_utf8); + if (r < 0) + return r; + if (r == 0) + return -EINVAL; + + good = true; + } + + /* If the IDNA and UTF8 questions are the same, merge their references */ + r = dns_question_is_equal(question_idna, question_utf8); + if (r < 0) + return r; + if (r > 0) + question_idna = question_utf8; + else { + if (dns_question_size(question_idna) > 0) { + r = dns_question_is_valid_for_query(question_idna); + if (r < 0) + return r; + if (r == 0) + return -EINVAL; + + good = true; + } + } + + if (!good) /* don't allow empty queries */ + return -EINVAL; + + if (m->n_dns_queries >= QUERIES_MAX) + return -EBUSY; + + q = new0(DnsQuery, 1); + if (!q) + return -ENOMEM; + + q->question_utf8 = dns_question_ref(question_utf8); + q->question_idna = dns_question_ref(question_idna); + q->ifindex = ifindex; + q->flags = flags; + q->answer_dnssec_result = _DNSSEC_RESULT_INVALID; + q->answer_protocol = _DNS_PROTOCOL_INVALID; + q->answer_family = AF_UNSPEC; + + /* First dump UTF8 question */ + DNS_QUESTION_FOREACH(key, question_utf8) + log_debug("Looking up RR for %s.", + dns_resource_key_to_string(key, key_str, sizeof key_str)); + + /* And then dump the IDNA question, but only what hasn't been dumped already through the UTF8 question. */ + DNS_QUESTION_FOREACH(key, question_idna) { + r = dns_question_contains(question_utf8, key); + if (r < 0) + return r; + if (r > 0) + continue; + + log_debug("Looking up IDNA RR for %s.", + dns_resource_key_to_string(key, key_str, sizeof key_str)); + } + + LIST_PREPEND(queries, m->dns_queries, q); + m->n_dns_queries++; + q->manager = m; + + if (ret) + *ret = q; + q = NULL; + + return 0; +} + +int dns_query_make_auxiliary(DnsQuery *q, DnsQuery *auxiliary_for) { + assert(q); + assert(auxiliary_for); + + /* Ensure that the query is not auxiliary yet, and + * nothing else is auxiliary to it either */ + assert(!q->auxiliary_for); + assert(!q->auxiliary_queries); + + /* Ensure that the unit we shall be made auxiliary for isn't + * auxiliary itself */ + assert(!auxiliary_for->auxiliary_for); + + if (auxiliary_for->n_auxiliary_queries >= AUXILIARY_QUERIES_MAX) + return -EAGAIN; + + LIST_PREPEND(auxiliary_queries, auxiliary_for->auxiliary_queries, q); + q->auxiliary_for = auxiliary_for; + + auxiliary_for->n_auxiliary_queries++; + return 0; +} + +static void dns_query_complete(DnsQuery *q, DnsTransactionState state) { + assert(q); + assert(!DNS_TRANSACTION_IS_LIVE(state)); + assert(DNS_TRANSACTION_IS_LIVE(q->state)); + + /* Note that this call might invalidate the query. Callers + * should hence not attempt to access the query or transaction + * after calling this function. */ + + q->state = state; + + dns_query_stop(q); + if (q->complete) + q->complete(q); +} + +static int on_query_timeout(sd_event_source *s, usec_t usec, void *userdata) { + DnsQuery *q = userdata; + + assert(s); + assert(q); + + dns_query_complete(q, DNS_TRANSACTION_TIMEOUT); + return 0; +} + +static int dns_query_add_candidate(DnsQuery *q, DnsScope *s) { + DnsQueryCandidate *c; + int r; + + assert(q); + assert(s); + + r = dns_query_candidate_new(&c, q, s); + if (r < 0) + return r; + + /* If this a single-label domain on DNS, we might append a suitable search domain first. */ + if ((q->flags & SD_RESOLVED_NO_SEARCH) == 0) { + r = dns_scope_name_needs_search_domain(s, dns_question_first_name(q->question_idna)); + if (r < 0) + goto fail; + if (r > 0) { + /* OK, we need a search domain now. Let's find one for this scope */ + + r = dns_query_candidate_next_search_domain(c); + if (r <= 0) /* if there's no search domain, then we won't add any transaction. */ + goto fail; + } + } + + r = dns_query_candidate_setup_transactions(c); + if (r < 0) + goto fail; + + return 0; + +fail: + dns_query_candidate_free(c); + return r; +} + +static int dns_query_synthesize_reply(DnsQuery *q, DnsTransactionState *state) { + _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL; + int r; + + assert(q); + assert(state); + + /* Tries to synthesize localhost RR replies (and others) where appropriate. Note that this is done *after* the + * the normal lookup finished. The data from the network hence takes precedence over the data we + * synthesize. (But note that many scopes refuse to resolve certain domain names) */ + + if (!IN_SET(*state, + DNS_TRANSACTION_RCODE_FAILURE, + DNS_TRANSACTION_NO_SERVERS, + DNS_TRANSACTION_TIMEOUT, + DNS_TRANSACTION_ATTEMPTS_MAX_REACHED, + DNS_TRANSACTION_NETWORK_DOWN, + DNS_TRANSACTION_NOT_FOUND)) + return 0; + + r = dns_synthesize_answer( + q->manager, + q->question_utf8, + q->ifindex, + &answer); + + if (r <= 0) + return r; + + dns_query_reset_answer(q); + + q->answer = answer; + answer = NULL; + q->answer_rcode = DNS_RCODE_SUCCESS; + q->answer_protocol = dns_synthesize_protocol(q->flags); + q->answer_family = dns_synthesize_family(q->flags); + q->answer_authenticated = true; + + *state = DNS_TRANSACTION_SUCCESS; + + return 1; +} + +static int dns_query_try_etc_hosts(DnsQuery *q) { + _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL; + int r; + + assert(q); + + /* Looks in /etc/hosts for matching entries. Note that this is done *before* the normal lookup is done. The + * data from /etc/hosts hence takes precedence over the network. */ + + r = manager_etc_hosts_lookup( + q->manager, + q->question_utf8, + &answer); + if (r <= 0) + return r; + + dns_query_reset_answer(q); + + q->answer = answer; + answer = NULL; + q->answer_rcode = DNS_RCODE_SUCCESS; + q->answer_protocol = dns_synthesize_protocol(q->flags); + q->answer_family = dns_synthesize_family(q->flags); + q->answer_authenticated = true; + + return 1; +} + +int dns_query_go(DnsQuery *q) { + DnsScopeMatch found = DNS_SCOPE_NO; + DnsScope *s, *first = NULL; + DnsQueryCandidate *c; + int r; + + assert(q); + + if (q->state != DNS_TRANSACTION_NULL) + return 0; + + r = dns_query_try_etc_hosts(q); + if (r < 0) + return r; + if (r > 0) { + dns_query_complete(q, DNS_TRANSACTION_SUCCESS); + return 1; + } + + LIST_FOREACH(scopes, s, q->manager->dns_scopes) { + DnsScopeMatch match; + const char *name; + + name = dns_question_first_name(dns_query_question_for_protocol(q, s->protocol)); + if (!name) + continue; + + match = dns_scope_good_domain(s, q->ifindex, q->flags, name); + if (match < 0) + return match; + + if (match == DNS_SCOPE_NO) + continue; + + found = match; + + if (match == DNS_SCOPE_YES) { + first = s; + break; + } else { + assert(match == DNS_SCOPE_MAYBE); + + if (!first) + first = s; + } + } + + if (found == DNS_SCOPE_NO) { + DnsTransactionState state = DNS_TRANSACTION_NO_SERVERS; + + r = dns_query_synthesize_reply(q, &state); + if (r < 0) + return r; + + dns_query_complete(q, state); + return 1; + } + + r = dns_query_add_candidate(q, first); + if (r < 0) + goto fail; + + LIST_FOREACH(scopes, s, first->scopes_next) { + DnsScopeMatch match; + const char *name; + + name = dns_question_first_name(dns_query_question_for_protocol(q, s->protocol)); + if (!name) + continue; + + match = dns_scope_good_domain(s, q->ifindex, q->flags, name); + if (match < 0) + goto fail; + + if (match != found) + continue; + + r = dns_query_add_candidate(q, s); + if (r < 0) + goto fail; + } + + dns_query_reset_answer(q); + + r = sd_event_add_time( + q->manager->event, + &q->timeout_event_source, + clock_boottime_or_monotonic(), + now(clock_boottime_or_monotonic()) + QUERY_TIMEOUT_USEC, 0, + on_query_timeout, q); + if (r < 0) + goto fail; + + (void) sd_event_source_set_description(q->timeout_event_source, "query-timeout"); + + q->state = DNS_TRANSACTION_PENDING; + q->block_ready++; + + /* Start the transactions */ + LIST_FOREACH(candidates_by_query, c, q->candidates) { + r = dns_query_candidate_go(c); + if (r < 0) { + q->block_ready--; + goto fail; + } + } + + q->block_ready--; + dns_query_ready(q); + + return 1; + +fail: + dns_query_stop(q); + return r; +} + +static void dns_query_accept(DnsQuery *q, DnsQueryCandidate *c) { + DnsTransactionState state = DNS_TRANSACTION_NO_SERVERS; + bool has_authenticated = false, has_non_authenticated = false; + DnssecResult dnssec_result_authenticated = _DNSSEC_RESULT_INVALID, dnssec_result_non_authenticated = _DNSSEC_RESULT_INVALID; + DnsTransaction *t; + Iterator i; + int r; + + assert(q); + + if (!c) { + r = dns_query_synthesize_reply(q, &state); + if (r < 0) + goto fail; + + dns_query_complete(q, state); + return; + } + + if (c->error_code != 0) { + /* If the candidate had an error condition of its own, start with that. */ + state = DNS_TRANSACTION_ERRNO; + q->answer = dns_answer_unref(q->answer); + q->answer_rcode = 0; + q->answer_dnssec_result = _DNSSEC_RESULT_INVALID; + q->answer_errno = c->error_code; + } + + SET_FOREACH(t, c->transactions, i) { + + switch (t->state) { + + case DNS_TRANSACTION_SUCCESS: { + /* We found a successfully reply, merge it into the answer */ + r = dns_answer_extend(&q->answer, t->answer); + if (r < 0) + goto fail; + + q->answer_rcode = t->answer_rcode; + q->answer_errno = 0; + + if (t->answer_authenticated) { + has_authenticated = true; + dnssec_result_authenticated = t->answer_dnssec_result; + } else { + has_non_authenticated = true; + dnssec_result_non_authenticated = t->answer_dnssec_result; + } + + state = DNS_TRANSACTION_SUCCESS; + break; + } + + case DNS_TRANSACTION_NULL: + case DNS_TRANSACTION_PENDING: + case DNS_TRANSACTION_VALIDATING: + case DNS_TRANSACTION_ABORTED: + /* Ignore transactions that didn't complete */ + continue; + + default: + /* Any kind of failure? Store the data away, + * if there's nothing stored yet. */ + + if (state == DNS_TRANSACTION_SUCCESS) + continue; + + q->answer = dns_answer_unref(q->answer); + q->answer_rcode = t->answer_rcode; + q->answer_dnssec_result = t->answer_dnssec_result; + q->answer_errno = t->answer_errno; + + state = t->state; + break; + } + } + + if (state == DNS_TRANSACTION_SUCCESS) { + q->answer_authenticated = has_authenticated && !has_non_authenticated; + q->answer_dnssec_result = q->answer_authenticated ? dnssec_result_authenticated : dnssec_result_non_authenticated; + } + + q->answer_protocol = c->scope->protocol; + q->answer_family = c->scope->family; + + dns_search_domain_unref(q->answer_search_domain); + q->answer_search_domain = dns_search_domain_ref(c->search_domain); + + r = dns_query_synthesize_reply(q, &state); + if (r < 0) + goto fail; + + dns_query_complete(q, state); + return; + +fail: + q->answer_errno = -r; + dns_query_complete(q, DNS_TRANSACTION_ERRNO); +} + +void dns_query_ready(DnsQuery *q) { + + DnsQueryCandidate *bad = NULL, *c; + bool pending = false; + + assert(q); + assert(DNS_TRANSACTION_IS_LIVE(q->state)); + + /* Note that this call might invalidate the query. Callers + * should hence not attempt to access the query or transaction + * after calling this function, unless the block_ready + * counter was explicitly bumped before doing so. */ + + if (q->block_ready > 0) + return; + + LIST_FOREACH(candidates_by_query, c, q->candidates) { + DnsTransactionState state; + + state = dns_query_candidate_state(c); + switch (state) { + + case DNS_TRANSACTION_SUCCESS: + /* One of the candidates is successful, + * let's use it, and copy its data out */ + dns_query_accept(q, c); + return; + + case DNS_TRANSACTION_NULL: + case DNS_TRANSACTION_PENDING: + case DNS_TRANSACTION_VALIDATING: + /* One of the candidates is still going on, + * let's maybe wait for it */ + pending = true; + break; + + default: + /* Any kind of failure */ + bad = c; + break; + } + } + + if (pending) + return; + + dns_query_accept(q, bad); +} + +static int dns_query_cname_redirect(DnsQuery *q, const DnsResourceRecord *cname) { + _cleanup_(dns_question_unrefp) DnsQuestion *nq_idna = NULL, *nq_utf8 = NULL; + int r, k; + + assert(q); + + q->n_cname_redirects++; + if (q->n_cname_redirects > CNAME_MAX) + return -ELOOP; + + r = dns_question_cname_redirect(q->question_idna, cname, &nq_idna); + if (r < 0) + return r; + else if (r > 0) + log_debug("Following CNAME/DNAME %s → %s.", dns_question_first_name(q->question_idna), dns_question_first_name(nq_idna)); + + k = dns_question_is_equal(q->question_idna, q->question_utf8); + if (k < 0) + return r; + if (k > 0) { + /* Same question? Shortcut new question generation */ + nq_utf8 = dns_question_ref(nq_idna); + k = r; + } else { + k = dns_question_cname_redirect(q->question_utf8, cname, &nq_utf8); + if (k < 0) + return k; + else if (k > 0) + log_debug("Following UTF8 CNAME/DNAME %s → %s.", dns_question_first_name(q->question_utf8), dns_question_first_name(nq_utf8)); + } + + if (r == 0 && k == 0) /* No actual cname happened? */ + return -ELOOP; + + if (q->answer_protocol == DNS_PROTOCOL_DNS) { + /* Don't permit CNAME redirects from unicast DNS to LLMNR or MulticastDNS, so that global resources + * cannot invade the local namespace. The opposite way we permit: local names may redirect to global + * ones. */ + + q->flags &= ~(SD_RESOLVED_LLMNR|SD_RESOLVED_MDNS); /* mask away the local protocols */ + } + + /* Turn off searching for the new name */ + q->flags |= SD_RESOLVED_NO_SEARCH; + + dns_question_unref(q->question_idna); + q->question_idna = nq_idna; + nq_idna = NULL; + + dns_question_unref(q->question_utf8); + q->question_utf8 = nq_utf8; + nq_utf8 = NULL; + + dns_query_free_candidates(q); + dns_query_reset_answer(q); + + q->state = DNS_TRANSACTION_NULL; + + return 0; +} + +int dns_query_process_cname(DnsQuery *q) { + _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *cname = NULL; + DnsQuestion *question; + DnsResourceRecord *rr; + int r; + + assert(q); + + if (!IN_SET(q->state, DNS_TRANSACTION_SUCCESS, DNS_TRANSACTION_NULL)) + return DNS_QUERY_NOMATCH; + + question = dns_query_question_for_protocol(q, q->answer_protocol); + + DNS_ANSWER_FOREACH(rr, q->answer) { + r = dns_question_matches_rr(question, rr, DNS_SEARCH_DOMAIN_NAME(q->answer_search_domain)); + if (r < 0) + return r; + if (r > 0) + return DNS_QUERY_MATCH; /* The answer matches directly, no need to follow cnames */ + + r = dns_question_matches_cname_or_dname(question, rr, DNS_SEARCH_DOMAIN_NAME(q->answer_search_domain)); + if (r < 0) + return r; + if (r > 0 && !cname) + cname = dns_resource_record_ref(rr); + } + + if (!cname) + return DNS_QUERY_NOMATCH; /* No match and no cname to follow */ + + if (q->flags & SD_RESOLVED_NO_CNAME) + return -ELOOP; + + /* OK, let's actually follow the CNAME */ + r = dns_query_cname_redirect(q, cname); + if (r < 0) + return r; + + /* Let's see if the answer can already answer the new + * redirected question */ + r = dns_query_process_cname(q); + if (r != DNS_QUERY_NOMATCH) + return r; + + /* OK, it cannot, let's begin with the new query */ + r = dns_query_go(q); + if (r < 0) + return r; + + return DNS_QUERY_RESTARTED; /* We restarted the query for a new cname */ +} + +static int on_bus_track(sd_bus_track *t, void *userdata) { + DnsQuery *q = userdata; + + assert(t); + assert(q); + + log_debug("Client of active query vanished, aborting query."); + dns_query_complete(q, DNS_TRANSACTION_ABORTED); + return 0; +} + +int dns_query_bus_track(DnsQuery *q, sd_bus_message *m) { + int r; + + assert(q); + assert(m); + + if (!q->bus_track) { + r = sd_bus_track_new(sd_bus_message_get_bus(m), &q->bus_track, on_bus_track, q); + if (r < 0) + return r; + } + + r = sd_bus_track_add_sender(q->bus_track, m); + if (r < 0) + return r; + + return 0; +} + +DnsQuestion* dns_query_question_for_protocol(DnsQuery *q, DnsProtocol protocol) { + assert(q); + + switch (protocol) { + + case DNS_PROTOCOL_DNS: + return q->question_idna; + + case DNS_PROTOCOL_MDNS: + case DNS_PROTOCOL_LLMNR: + return q->question_utf8; + + default: + return NULL; + } +} + +const char *dns_query_string(DnsQuery *q) { + const char *name; + int r; + + /* Returns a somewhat useful human-readable lookup key string for this query */ + + if (q->request_address_string) + return q->request_address_string; + + if (q->request_address_valid) { + r = in_addr_to_string(q->request_family, &q->request_address, &q->request_address_string); + if (r >= 0) + return q->request_address_string; + } + + name = dns_question_first_name(q->question_utf8); + if (name) + return name; + + return dns_question_first_name(q->question_idna); +} diff --git a/src/grp-resolve/systemd-resolved/resolved-dns-query.h b/src/grp-resolve/systemd-resolved/resolved-dns-query.h new file mode 100644 index 0000000000..bc26a58f21 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-dns-query.h @@ -0,0 +1,141 @@ +#pragma once + +/*** + This file is part of systemd. + + Copyright 2014 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + + +#include <systemd/sd-bus.h> + +#include "basic-dns/resolved-dns-answer.h" +#include "basic-dns/resolved-dns-question.h" +#include "systemd-basic/set.h" + +typedef struct DnsQuery DnsQuery; +typedef struct DnsQueryCandidate DnsQueryCandidate; + +#include "resolved-dns-search-domain.h" +#include "resolved-dns-stream.h" + +struct DnsQueryCandidate { + DnsQuery *query; + DnsScope *scope; + + DnsSearchDomain *search_domain; + + int error_code; + Set *transactions; + + LIST_FIELDS(DnsQueryCandidate, candidates_by_query); + LIST_FIELDS(DnsQueryCandidate, candidates_by_scope); +}; + +struct DnsQuery { + Manager *manager; + + /* When resolving a service, we first create a TXT+SRV query, + * and then for the hostnames we discover auxiliary A+AAAA + * queries. This pointer always points from the auxiliary + * queries back to the TXT+SRV query. */ + DnsQuery *auxiliary_for; + LIST_HEAD(DnsQuery, auxiliary_queries); + unsigned n_auxiliary_queries; + int auxiliary_result; + + /* The question, formatted in IDNA for use on classic DNS, and as UTF8 for use in LLMNR or mDNS. Note that even + * on classic DNS some labels might use UTF8 encoding. Specifically, DNS-SD service names (in contrast to their + * domain suffixes) use UTF-8 encoding even on DNS. Thus, the difference between these two fields is mostly + * relevant only for explicit *hostname* lookups as well as the domain suffixes of service lookups. */ + DnsQuestion *question_idna; + DnsQuestion *question_utf8; + + uint64_t flags; + int ifindex; + + /* If true, A or AAAA RR lookups will be suppressed on links with no routable address of the matching address + * family */ + bool suppress_unroutable_family; + + + /* If true, the RR TTLs of the answer will be clamped by their current left validity in the cache */ + bool clamp_ttl; + + DnsTransactionState state; + unsigned n_cname_redirects; + + LIST_HEAD(DnsQueryCandidate, candidates); + sd_event_source *timeout_event_source; + + /* Discovered data */ + DnsAnswer *answer; + int answer_rcode; + DnssecResult answer_dnssec_result; + bool answer_authenticated; + DnsProtocol answer_protocol; + int answer_family; + DnsSearchDomain *answer_search_domain; + int answer_errno; /* if state is DNS_TRANSACTION_ERRNO */ + + /* Bus client information */ + sd_bus_message *request; + int request_family; + bool request_address_valid; + union in_addr_union request_address; + unsigned block_all_complete; + char *request_address_string; + + /* DNS stub information */ + DnsPacket *request_dns_packet; + DnsStream *request_dns_stream; + + /* Completion callback */ + void (*complete)(DnsQuery* q); + unsigned block_ready; + + sd_bus_track *bus_track; + + LIST_FIELDS(DnsQuery, queries); + LIST_FIELDS(DnsQuery, auxiliary_queries); +}; + +enum { + DNS_QUERY_MATCH, + DNS_QUERY_NOMATCH, + DNS_QUERY_RESTARTED, +}; + +DnsQueryCandidate* dns_query_candidate_free(DnsQueryCandidate *c); +void dns_query_candidate_notify(DnsQueryCandidate *c); + +int dns_query_new(Manager *m, DnsQuery **q, DnsQuestion *question_utf8, DnsQuestion *question_idna, int family, uint64_t flags); +DnsQuery *dns_query_free(DnsQuery *q); + +int dns_query_make_auxiliary(DnsQuery *q, DnsQuery *auxiliary_for); + +int dns_query_go(DnsQuery *q); +void dns_query_ready(DnsQuery *q); + +int dns_query_process_cname(DnsQuery *q); + +int dns_query_bus_track(DnsQuery *q, sd_bus_message *m); + +DnsQuestion* dns_query_question_for_protocol(DnsQuery *q, DnsProtocol protocol); + +const char *dns_query_string(DnsQuery *q); + +DEFINE_TRIVIAL_CLEANUP_FUNC(DnsQuery*, dns_query_free); diff --git a/src/grp-resolve/systemd-resolved/resolved-dns-scope.c b/src/grp-resolve/systemd-resolved/resolved-dns-scope.c new file mode 100644 index 0000000000..9f20fd304a --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-dns-scope.c @@ -0,0 +1,1044 @@ +/*** + This file is part of systemd. + + Copyright 2014 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include <netinet/tcp.h> + +#include "systemd-basic/af-list.h" +#include "systemd-basic/alloc-util.h" +#include "systemd-basic/fd-util.h" +#include "systemd-basic/hostname-util.h" +#include "systemd-basic/missing.h" +#include "systemd-basic/random-util.h" +#include "systemd-basic/socket-util.h" +#include "systemd-basic/strv.h" +#include "systemd-shared/dns-domain.h" + +#include "resolved-dns-scope.h" +#include "resolved-llmnr.h" +#include "resolved-mdns.h" + +#define MULTICAST_RATELIMIT_INTERVAL_USEC (1*USEC_PER_SEC) +#define MULTICAST_RATELIMIT_BURST 1000 + +/* After how much time to repeat LLMNR requests, see RFC 4795 Section 7 */ +#define MULTICAST_RESEND_TIMEOUT_MIN_USEC (100 * USEC_PER_MSEC) +#define MULTICAST_RESEND_TIMEOUT_MAX_USEC (1 * USEC_PER_SEC) + +int dns_scope_new(Manager *m, DnsScope **ret, Link *l, DnsProtocol protocol, int family) { + DnsScope *s; + + assert(m); + assert(ret); + + s = new0(DnsScope, 1); + if (!s) + return -ENOMEM; + + s->manager = m; + s->link = l; + s->protocol = protocol; + s->family = family; + s->resend_timeout = MULTICAST_RESEND_TIMEOUT_MIN_USEC; + + if (protocol == DNS_PROTOCOL_DNS) { + /* Copy DNSSEC mode from the link if it is set there, + * otherwise take the manager's DNSSEC mode. Note that + * we copy this only at scope creation time, and do + * not update it from the on, even if the setting + * changes. */ + + if (l) + s->dnssec_mode = link_get_dnssec_mode(l); + else + s->dnssec_mode = manager_get_dnssec_mode(m); + } else + s->dnssec_mode = DNSSEC_NO; + + LIST_PREPEND(scopes, m->dns_scopes, s); + + dns_scope_llmnr_membership(s, true); + dns_scope_mdns_membership(s, true); + + log_debug("New scope on link %s, protocol %s, family %s", l ? l->name : "*", dns_protocol_to_string(protocol), family == AF_UNSPEC ? "*" : af_to_name(family)); + + /* Enforce ratelimiting for the multicast protocols */ + RATELIMIT_INIT(s->ratelimit, MULTICAST_RATELIMIT_INTERVAL_USEC, MULTICAST_RATELIMIT_BURST); + + *ret = s; + return 0; +} + +static void dns_scope_abort_transactions(DnsScope *s) { + assert(s); + + while (s->transactions) { + DnsTransaction *t = s->transactions; + + /* Abort the transaction, but make sure it is not + * freed while we still look at it */ + + t->block_gc++; + if (DNS_TRANSACTION_IS_LIVE(t->state)) + dns_transaction_complete(t, DNS_TRANSACTION_ABORTED); + t->block_gc--; + + dns_transaction_free(t); + } +} + +DnsScope* dns_scope_free(DnsScope *s) { + DnsResourceRecord *rr; + + if (!s) + return NULL; + + log_debug("Removing scope on link %s, protocol %s, family %s", s->link ? s->link->name : "*", dns_protocol_to_string(s->protocol), s->family == AF_UNSPEC ? "*" : af_to_name(s->family)); + + dns_scope_llmnr_membership(s, false); + dns_scope_mdns_membership(s, false); + dns_scope_abort_transactions(s); + + while (s->query_candidates) + dns_query_candidate_free(s->query_candidates); + + hashmap_free(s->transactions_by_key); + + while ((rr = ordered_hashmap_steal_first(s->conflict_queue))) + dns_resource_record_unref(rr); + + ordered_hashmap_free(s->conflict_queue); + sd_event_source_unref(s->conflict_event_source); + + dns_cache_flush(&s->cache); + dns_zone_flush(&s->zone); + + LIST_REMOVE(scopes, s->manager->dns_scopes, s); + return mfree(s); +} + +DnsServer *dns_scope_get_dns_server(DnsScope *s) { + assert(s); + + if (s->protocol != DNS_PROTOCOL_DNS) + return NULL; + + if (s->link) + return link_get_dns_server(s->link); + else + return manager_get_dns_server(s->manager); +} + +void dns_scope_next_dns_server(DnsScope *s) { + assert(s); + + if (s->protocol != DNS_PROTOCOL_DNS) + return; + + if (s->link) + link_next_dns_server(s->link); + else + manager_next_dns_server(s->manager); +} + +void dns_scope_packet_received(DnsScope *s, usec_t rtt) { + assert(s); + + if (rtt <= s->max_rtt) + return; + + s->max_rtt = rtt; + s->resend_timeout = MIN(MAX(MULTICAST_RESEND_TIMEOUT_MIN_USEC, s->max_rtt * 2), MULTICAST_RESEND_TIMEOUT_MAX_USEC); +} + +void dns_scope_packet_lost(DnsScope *s, usec_t usec) { + assert(s); + + if (s->resend_timeout <= usec) + s->resend_timeout = MIN(s->resend_timeout * 2, MULTICAST_RESEND_TIMEOUT_MAX_USEC); +} + +static int dns_scope_emit_one(DnsScope *s, int fd, DnsPacket *p) { + union in_addr_union addr; + int ifindex = 0, r; + int family; + uint32_t mtu; + + assert(s); + assert(p); + assert(p->protocol == s->protocol); + + if (s->link) { + mtu = s->link->mtu; + ifindex = s->link->ifindex; + } else + mtu = manager_find_mtu(s->manager); + + switch (s->protocol) { + + case DNS_PROTOCOL_DNS: + assert(fd >= 0); + + if (DNS_PACKET_QDCOUNT(p) > 1) + return -EOPNOTSUPP; + + if (p->size > DNS_PACKET_UNICAST_SIZE_MAX) + return -EMSGSIZE; + + if (p->size + UDP_PACKET_HEADER_SIZE > mtu) + return -EMSGSIZE; + + r = manager_write(s->manager, fd, p); + if (r < 0) + return r; + + break; + + case DNS_PROTOCOL_LLMNR: + assert(fd < 0); + + if (DNS_PACKET_QDCOUNT(p) > 1) + return -EOPNOTSUPP; + + if (!ratelimit_test(&s->ratelimit)) + return -EBUSY; + + family = s->family; + + if (family == AF_INET) { + addr.in = LLMNR_MULTICAST_IPV4_ADDRESS; + fd = manager_llmnr_ipv4_udp_fd(s->manager); + } else if (family == AF_INET6) { + addr.in6 = LLMNR_MULTICAST_IPV6_ADDRESS; + fd = manager_llmnr_ipv6_udp_fd(s->manager); + } else + return -EAFNOSUPPORT; + if (fd < 0) + return fd; + + r = manager_send(s->manager, fd, ifindex, family, &addr, LLMNR_PORT, NULL, p); + if (r < 0) + return r; + + break; + + case DNS_PROTOCOL_MDNS: + assert(fd < 0); + + if (!ratelimit_test(&s->ratelimit)) + return -EBUSY; + + family = s->family; + + if (family == AF_INET) { + addr.in = MDNS_MULTICAST_IPV4_ADDRESS; + fd = manager_mdns_ipv4_fd(s->manager); + } else if (family == AF_INET6) { + addr.in6 = MDNS_MULTICAST_IPV6_ADDRESS; + fd = manager_mdns_ipv6_fd(s->manager); + } else + return -EAFNOSUPPORT; + if (fd < 0) + return fd; + + r = manager_send(s->manager, fd, ifindex, family, &addr, MDNS_PORT, NULL, p); + if (r < 0) + return r; + + break; + + default: + return -EAFNOSUPPORT; + } + + return 1; +} + +int dns_scope_emit_udp(DnsScope *s, int fd, DnsPacket *p) { + int r; + + assert(s); + assert(p); + assert(p->protocol == s->protocol); + assert((s->protocol == DNS_PROTOCOL_DNS) == (fd >= 0)); + + do { + /* If there are multiple linked packets, set the TC bit in all but the last of them */ + if (p->more) { + assert(p->protocol == DNS_PROTOCOL_MDNS); + dns_packet_set_flags(p, true, true); + } + + r = dns_scope_emit_one(s, fd, p); + if (r < 0) + return r; + + p = p->more; + } while (p); + + return 0; +} + +static int dns_scope_socket( + DnsScope *s, + int type, + int family, + const union in_addr_union *address, + DnsServer *server, + uint16_t port) { + + _cleanup_close_ int fd = -1; + union sockaddr_union sa = {}; + socklen_t salen; + static const int one = 1; + int ret, r, ifindex; + + assert(s); + + if (server) { + assert(family == AF_UNSPEC); + assert(!address); + + ifindex = dns_server_ifindex(server); + + sa.sa.sa_family = server->family; + if (server->family == AF_INET) { + sa.in.sin_port = htobe16(port); + sa.in.sin_addr = server->address.in; + salen = sizeof(sa.in); + } else if (server->family == AF_INET6) { + sa.in6.sin6_port = htobe16(port); + sa.in6.sin6_addr = server->address.in6; + sa.in6.sin6_scope_id = ifindex; + salen = sizeof(sa.in6); + } else + return -EAFNOSUPPORT; + } else { + assert(family != AF_UNSPEC); + assert(address); + + sa.sa.sa_family = family; + ifindex = s->link ? s->link->ifindex : 0; + + if (family == AF_INET) { + sa.in.sin_port = htobe16(port); + sa.in.sin_addr = address->in; + salen = sizeof(sa.in); + } else if (family == AF_INET6) { + sa.in6.sin6_port = htobe16(port); + sa.in6.sin6_addr = address->in6; + sa.in6.sin6_scope_id = ifindex; + salen = sizeof(sa.in6); + } else + return -EAFNOSUPPORT; + } + + fd = socket(sa.sa.sa_family, type|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); + if (fd < 0) + return -errno; + + if (type == SOCK_STREAM) { + r = setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &one, sizeof(one)); + if (r < 0) + return -errno; + } + + if (s->link) { + be32_t ifindex_be = htobe32(ifindex); + + if (sa.sa.sa_family == AF_INET) { + r = setsockopt(fd, IPPROTO_IP, IP_UNICAST_IF, &ifindex_be, sizeof(ifindex_be)); + if (r < 0) + return -errno; + } else if (sa.sa.sa_family == AF_INET6) { + r = setsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_IF, &ifindex_be, sizeof(ifindex_be)); + if (r < 0) + return -errno; + } + } + + if (s->protocol == DNS_PROTOCOL_LLMNR) { + /* RFC 4795, section 2.5 requires the TTL to be set to 1 */ + + if (sa.sa.sa_family == AF_INET) { + r = setsockopt(fd, IPPROTO_IP, IP_TTL, &one, sizeof(one)); + if (r < 0) + return -errno; + } else if (sa.sa.sa_family == AF_INET6) { + r = setsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &one, sizeof(one)); + if (r < 0) + return -errno; + } + } + + r = connect(fd, &sa.sa, salen); + if (r < 0 && errno != EINPROGRESS) + return -errno; + + ret = fd; + fd = -1; + + return ret; +} + +int dns_scope_socket_udp(DnsScope *s, DnsServer *server, uint16_t port) { + return dns_scope_socket(s, SOCK_DGRAM, AF_UNSPEC, NULL, server, port); +} + +int dns_scope_socket_tcp(DnsScope *s, int family, const union in_addr_union *address, DnsServer *server, uint16_t port) { + return dns_scope_socket(s, SOCK_STREAM, family, address, server, port); +} + +DnsScopeMatch dns_scope_good_domain(DnsScope *s, int ifindex, uint64_t flags, const char *domain) { + DnsSearchDomain *d; + DnsServer *dns_server; + + assert(s); + assert(domain); + + /* Checks if the specified domain is something to look up on + * this scope. Note that this accepts non-qualified hostnames, + * i.e. those without any search path prefixed yet. */ + + if (ifindex != 0 && (!s->link || s->link->ifindex != ifindex)) + return DNS_SCOPE_NO; + + if ((SD_RESOLVED_FLAGS_MAKE(s->protocol, s->family, 0) & flags) == 0) + return DNS_SCOPE_NO; + + /* Never resolve any loopback hostname or IP address via DNS, + * LLMNR or mDNS. Instead, always rely on synthesized RRs for + * these. */ + if (is_localhost(domain) || + dns_name_endswith(domain, "127.in-addr.arpa") > 0 || + dns_name_equal(domain, "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa") > 0) + return DNS_SCOPE_NO; + + /* Never respond to some of the domains listed in RFC6303 */ + if (dns_name_endswith(domain, "0.in-addr.arpa") > 0 || + dns_name_equal(domain, "255.255.255.255.in-addr.arpa") > 0 || + dns_name_equal(domain, "0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa") > 0) + return DNS_SCOPE_NO; + + /* Never respond to some of the domains listed in RFC6761 */ + if (dns_name_endswith(domain, "invalid") > 0) + return DNS_SCOPE_NO; + + /* Always honour search domains for routing queries. Note that + * we return DNS_SCOPE_YES here, rather than just + * DNS_SCOPE_MAYBE, which means wildcard scopes won't be + * considered anymore. */ + LIST_FOREACH(domains, d, dns_scope_get_search_domains(s)) + if (dns_name_endswith(domain, d->name) > 0) + return DNS_SCOPE_YES; + + /* If the DNS server has route-only domains, don't send other requests + * to it. This would be a privacy violation, will most probably fail + * anyway, and adds unnecessary load. */ + dns_server = dns_scope_get_dns_server(s); + if (dns_server && dns_server_limited_domains(dns_server)) + return DNS_SCOPE_NO; + + switch (s->protocol) { + + case DNS_PROTOCOL_DNS: + + /* Exclude link-local IP ranges */ + if (dns_name_endswith(domain, "254.169.in-addr.arpa") == 0 && + dns_name_endswith(domain, "8.e.f.ip6.arpa") == 0 && + dns_name_endswith(domain, "9.e.f.ip6.arpa") == 0 && + dns_name_endswith(domain, "a.e.f.ip6.arpa") == 0 && + dns_name_endswith(domain, "b.e.f.ip6.arpa") == 0 && + /* If networks use .local in their private setups, they are supposed to also add .local to their search + * domains, which we already checked above. Otherwise, we consider .local specific to mDNS and won't + * send such queries ordinary DNS servers. */ + dns_name_endswith(domain, "local") == 0) + return DNS_SCOPE_MAYBE; + + return DNS_SCOPE_NO; + + case DNS_PROTOCOL_MDNS: + if ((s->family == AF_INET && dns_name_endswith(domain, "in-addr.arpa") > 0) || + (s->family == AF_INET6 && dns_name_endswith(domain, "ip6.arpa") > 0) || + (dns_name_endswith(domain, "local") > 0 && /* only resolve names ending in .local via mDNS */ + dns_name_equal(domain, "local") == 0 && /* but not the single-label "local" name itself */ + manager_is_own_hostname(s->manager, domain) <= 0)) /* never resolve the local hostname via mDNS */ + return DNS_SCOPE_MAYBE; + + return DNS_SCOPE_NO; + + case DNS_PROTOCOL_LLMNR: + if ((s->family == AF_INET && dns_name_endswith(domain, "in-addr.arpa") > 0) || + (s->family == AF_INET6 && dns_name_endswith(domain, "ip6.arpa") > 0) || + (dns_name_is_single_label(domain) && /* only resolve single label names via LLMNR */ + !is_gateway_hostname(domain) && /* don't resolve "gateway" with LLMNR, let nss-myhostname handle this */ + manager_is_own_hostname(s->manager, domain) <= 0)) /* never resolve the local hostname via LLMNR */ + return DNS_SCOPE_MAYBE; + + return DNS_SCOPE_NO; + + default: + assert_not_reached("Unknown scope protocol"); + } +} + +bool dns_scope_good_key(DnsScope *s, const DnsResourceKey *key) { + int key_family; + + assert(s); + assert(key); + + /* Check if it makes sense to resolve the specified key on + * this scope. Note that this call assumes as fully qualified + * name, i.e. the search suffixes already appended. */ + + if (key->class != DNS_CLASS_IN) + return false; + + if (s->protocol == DNS_PROTOCOL_DNS) { + + /* On classic DNS, looking up non-address RRs is always + * fine. (Specifically, we want to permit looking up + * DNSKEY and DS records on the root and top-level + * domains.) */ + if (!dns_resource_key_is_address(key)) + return true; + + /* However, we refuse to look up A and AAAA RRs on the + * root and single-label domains, under the assumption + * that those should be resolved via LLMNR or search + * path only, and should not be leaked onto the + * internet. */ + return !(dns_name_is_single_label(dns_resource_key_name(key)) || + dns_name_is_root(dns_resource_key_name(key))); + } + + /* On mDNS and LLMNR, send A and AAAA queries only on the + * respective scopes */ + + key_family = dns_type_to_af(key->type); + if (key_family < 0) + return true; + + return key_family == s->family; +} + +static int dns_scope_multicast_membership(DnsScope *s, bool b, struct in_addr in, struct in6_addr in6) { + int fd; + + assert(s); + assert(s->link); + + if (s->family == AF_INET) { + struct ip_mreqn mreqn = { + .imr_multiaddr = in, + .imr_ifindex = s->link->ifindex, + }; + + fd = manager_llmnr_ipv4_udp_fd(s->manager); + if (fd < 0) + return fd; + + /* Always first try to drop membership before we add + * one. This is necessary on some devices, such as + * veth. */ + if (b) + (void) setsockopt(fd, IPPROTO_IP, IP_DROP_MEMBERSHIP, &mreqn, sizeof(mreqn)); + + if (setsockopt(fd, IPPROTO_IP, b ? IP_ADD_MEMBERSHIP : IP_DROP_MEMBERSHIP, &mreqn, sizeof(mreqn)) < 0) + return -errno; + + } else if (s->family == AF_INET6) { + struct ipv6_mreq mreq = { + .ipv6mr_multiaddr = in6, + .ipv6mr_interface = s->link->ifindex, + }; + + fd = manager_llmnr_ipv6_udp_fd(s->manager); + if (fd < 0) + return fd; + + if (b) + (void) setsockopt(fd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP, &mreq, sizeof(mreq)); + + if (setsockopt(fd, IPPROTO_IPV6, b ? IPV6_ADD_MEMBERSHIP : IPV6_DROP_MEMBERSHIP, &mreq, sizeof(mreq)) < 0) + return -errno; + } else + return -EAFNOSUPPORT; + + return 0; +} + +int dns_scope_llmnr_membership(DnsScope *s, bool b) { + assert(s); + + if (s->protocol != DNS_PROTOCOL_LLMNR) + return 0; + + return dns_scope_multicast_membership(s, b, LLMNR_MULTICAST_IPV4_ADDRESS, LLMNR_MULTICAST_IPV6_ADDRESS); +} + +int dns_scope_mdns_membership(DnsScope *s, bool b) { + assert(s); + + if (s->protocol != DNS_PROTOCOL_MDNS) + return 0; + + return dns_scope_multicast_membership(s, b, MDNS_MULTICAST_IPV4_ADDRESS, MDNS_MULTICAST_IPV6_ADDRESS); +} + +static int dns_scope_make_reply_packet( + DnsScope *s, + uint16_t id, + int rcode, + DnsQuestion *q, + DnsAnswer *answer, + DnsAnswer *soa, + bool tentative, + DnsPacket **ret) { + + _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; + int r; + + assert(s); + assert(ret); + + if (dns_question_isempty(q) && + dns_answer_isempty(answer) && + dns_answer_isempty(soa)) + return -EINVAL; + + r = dns_packet_new(&p, s->protocol, 0); + if (r < 0) + return r; + + DNS_PACKET_HEADER(p)->id = id; + DNS_PACKET_HEADER(p)->flags = htobe16(DNS_PACKET_MAKE_FLAGS( + 1 /* qr */, + 0 /* opcode */, + 0 /* c */, + 0 /* tc */, + tentative, + 0 /* (ra) */, + 0 /* (ad) */, + 0 /* (cd) */, + rcode)); + + r = dns_packet_append_question(p, q); + if (r < 0) + return r; + DNS_PACKET_HEADER(p)->qdcount = htobe16(dns_question_size(q)); + + r = dns_packet_append_answer(p, answer); + if (r < 0) + return r; + DNS_PACKET_HEADER(p)->ancount = htobe16(dns_answer_size(answer)); + + r = dns_packet_append_answer(p, soa); + if (r < 0) + return r; + DNS_PACKET_HEADER(p)->arcount = htobe16(dns_answer_size(soa)); + + *ret = p; + p = NULL; + + return 0; +} + +static void dns_scope_verify_conflicts(DnsScope *s, DnsPacket *p) { + DnsResourceRecord *rr; + DnsResourceKey *key; + + assert(s); + assert(p); + + DNS_QUESTION_FOREACH(key, p->question) + dns_zone_verify_conflicts(&s->zone, key); + + DNS_ANSWER_FOREACH(rr, p->answer) + dns_zone_verify_conflicts(&s->zone, rr->key); +} + +void dns_scope_process_query(DnsScope *s, DnsStream *stream, DnsPacket *p) { + _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL, *soa = NULL; + _cleanup_(dns_packet_unrefp) DnsPacket *reply = NULL; + DnsResourceKey *key = NULL; + bool tentative = false; + int r; + + assert(s); + assert(p); + + if (p->protocol != DNS_PROTOCOL_LLMNR) + return; + + if (p->ipproto == IPPROTO_UDP) { + /* Don't accept UDP queries directed to anything but + * the LLMNR multicast addresses. See RFC 4795, + * section 2.5. */ + + if (p->family == AF_INET && !in_addr_equal(AF_INET, &p->destination, (union in_addr_union*) &LLMNR_MULTICAST_IPV4_ADDRESS)) + return; + + if (p->family == AF_INET6 && !in_addr_equal(AF_INET6, &p->destination, (union in_addr_union*) &LLMNR_MULTICAST_IPV6_ADDRESS)) + return; + } + + r = dns_packet_extract(p); + if (r < 0) { + log_debug_errno(r, "Failed to extract resource records from incoming packet: %m"); + return; + } + + if (DNS_PACKET_LLMNR_C(p)) { + /* Somebody notified us about a possible conflict */ + dns_scope_verify_conflicts(s, p); + return; + } + + assert(dns_question_size(p->question) == 1); + key = p->question->keys[0]; + + r = dns_zone_lookup(&s->zone, key, 0, &answer, &soa, &tentative); + if (r < 0) { + log_debug_errno(r, "Failed to lookup key: %m"); + return; + } + if (r == 0) + return; + + if (answer) + dns_answer_order_by_scope(answer, in_addr_is_link_local(p->family, &p->sender) > 0); + + r = dns_scope_make_reply_packet(s, DNS_PACKET_ID(p), DNS_RCODE_SUCCESS, p->question, answer, soa, tentative, &reply); + if (r < 0) { + log_debug_errno(r, "Failed to build reply packet: %m"); + return; + } + + if (stream) { + r = dns_stream_write_packet(stream, reply); + if (r < 0) { + log_debug_errno(r, "Failed to enqueue reply packet: %m"); + return; + } + + /* Let's take an extra reference on this stream, so that it stays around after returning. The reference + * will be dangling until the stream is disconnected, and the default completion handler of the stream + * will then unref the stream and destroy it */ + if (DNS_STREAM_QUEUED(stream)) + dns_stream_ref(stream); + } else { + int fd; + + if (!ratelimit_test(&s->ratelimit)) + return; + + if (p->family == AF_INET) + fd = manager_llmnr_ipv4_udp_fd(s->manager); + else if (p->family == AF_INET6) + fd = manager_llmnr_ipv6_udp_fd(s->manager); + else { + log_debug("Unknown protocol"); + return; + } + if (fd < 0) { + log_debug_errno(fd, "Failed to get reply socket: %m"); + return; + } + + /* Note that we always immediately reply to all LLMNR + * requests, and do not wait any time, since we + * verified uniqueness for all records. Also see RFC + * 4795, Section 2.7 */ + + r = manager_send(s->manager, fd, p->ifindex, p->family, &p->sender, p->sender_port, NULL, reply); + if (r < 0) { + log_debug_errno(r, "Failed to send reply packet: %m"); + return; + } + } +} + +DnsTransaction *dns_scope_find_transaction(DnsScope *scope, DnsResourceKey *key, bool cache_ok) { + DnsTransaction *t; + + assert(scope); + assert(key); + + /* Try to find an ongoing transaction that is a equal to the + * specified question */ + t = hashmap_get(scope->transactions_by_key, key); + if (!t) + return NULL; + + /* Refuse reusing transactions that completed based on cached + * data instead of a real packet, if that's requested. */ + if (!cache_ok && + IN_SET(t->state, DNS_TRANSACTION_SUCCESS, DNS_TRANSACTION_RCODE_FAILURE) && + t->answer_source != DNS_TRANSACTION_NETWORK) + return NULL; + + return t; +} + +static int dns_scope_make_conflict_packet( + DnsScope *s, + DnsResourceRecord *rr, + DnsPacket **ret) { + + _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; + int r; + + assert(s); + assert(rr); + assert(ret); + + r = dns_packet_new(&p, s->protocol, 0); + if (r < 0) + return r; + + DNS_PACKET_HEADER(p)->flags = htobe16(DNS_PACKET_MAKE_FLAGS( + 0 /* qr */, + 0 /* opcode */, + 1 /* conflict */, + 0 /* tc */, + 0 /* t */, + 0 /* (ra) */, + 0 /* (ad) */, + 0 /* (cd) */, + 0)); + + /* For mDNS, the transaction ID should always be 0 */ + if (s->protocol != DNS_PROTOCOL_MDNS) + random_bytes(&DNS_PACKET_HEADER(p)->id, sizeof(uint16_t)); + + DNS_PACKET_HEADER(p)->qdcount = htobe16(1); + DNS_PACKET_HEADER(p)->arcount = htobe16(1); + + r = dns_packet_append_key(p, rr->key, NULL); + if (r < 0) + return r; + + r = dns_packet_append_rr(p, rr, NULL, NULL); + if (r < 0) + return r; + + *ret = p; + p = NULL; + + return 0; +} + +static int on_conflict_dispatch(sd_event_source *es, usec_t usec, void *userdata) { + DnsScope *scope = userdata; + int r; + + assert(es); + assert(scope); + + scope->conflict_event_source = sd_event_source_unref(scope->conflict_event_source); + + for (;;) { + _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL; + _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; + + rr = ordered_hashmap_steal_first(scope->conflict_queue); + if (!rr) + break; + + r = dns_scope_make_conflict_packet(scope, rr, &p); + if (r < 0) { + log_error_errno(r, "Failed to make conflict packet: %m"); + return 0; + } + + r = dns_scope_emit_udp(scope, -1, p); + if (r < 0) + log_debug_errno(r, "Failed to send conflict packet: %m"); + } + + return 0; +} + +int dns_scope_notify_conflict(DnsScope *scope, DnsResourceRecord *rr) { + usec_t jitter; + int r; + + assert(scope); + assert(rr); + + /* We don't send these queries immediately. Instead, we queue + * them, and send them after some jitter delay. */ + r = ordered_hashmap_ensure_allocated(&scope->conflict_queue, &dns_resource_key_hash_ops); + if (r < 0) { + log_oom(); + return r; + } + + /* We only place one RR per key in the conflict + * messages, not all of them. That should be enough to + * indicate where there might be a conflict */ + r = ordered_hashmap_put(scope->conflict_queue, rr->key, rr); + if (r == -EEXIST || r == 0) + return 0; + if (r < 0) + return log_debug_errno(r, "Failed to queue conflicting RR: %m"); + + dns_resource_record_ref(rr); + + if (scope->conflict_event_source) + return 0; + + random_bytes(&jitter, sizeof(jitter)); + jitter %= LLMNR_JITTER_INTERVAL_USEC; + + r = sd_event_add_time(scope->manager->event, + &scope->conflict_event_source, + clock_boottime_or_monotonic(), + now(clock_boottime_or_monotonic()) + jitter, + LLMNR_JITTER_INTERVAL_USEC, + on_conflict_dispatch, scope); + if (r < 0) + return log_debug_errno(r, "Failed to add conflict dispatch event: %m"); + + (void) sd_event_source_set_description(scope->conflict_event_source, "scope-conflict"); + + return 0; +} + +void dns_scope_check_conflicts(DnsScope *scope, DnsPacket *p) { + unsigned i; + int r; + + assert(scope); + assert(p); + + if (p->protocol != DNS_PROTOCOL_LLMNR) + return; + + if (DNS_PACKET_RRCOUNT(p) <= 0) + return; + + if (DNS_PACKET_LLMNR_C(p) != 0) + return; + + if (DNS_PACKET_LLMNR_T(p) != 0) + return; + + if (manager_our_packet(scope->manager, p)) + return; + + r = dns_packet_extract(p); + if (r < 0) { + log_debug_errno(r, "Failed to extract packet: %m"); + return; + } + + log_debug("Checking for conflicts..."); + + for (i = 0; i < p->answer->n_rrs; i++) { + + /* Check for conflicts against the local zone. If we + * found one, we won't check any further */ + r = dns_zone_check_conflicts(&scope->zone, p->answer->items[i].rr); + if (r != 0) + continue; + + /* Check for conflicts against the local cache. If so, + * send out an advisory query, to inform everybody */ + r = dns_cache_check_conflicts(&scope->cache, p->answer->items[i].rr, p->family, &p->sender); + if (r <= 0) + continue; + + dns_scope_notify_conflict(scope, p->answer->items[i].rr); + } +} + +void dns_scope_dump(DnsScope *s, FILE *f) { + assert(s); + + if (!f) + f = stdout; + + fputs("[Scope protocol=", f); + fputs(dns_protocol_to_string(s->protocol), f); + + if (s->link) { + fputs(" interface=", f); + fputs(s->link->name, f); + } + + if (s->family != AF_UNSPEC) { + fputs(" family=", f); + fputs(af_to_name(s->family), f); + } + + fputs("]\n", f); + + if (!dns_zone_is_empty(&s->zone)) { + fputs("ZONE:\n", f); + dns_zone_dump(&s->zone, f); + } + + if (!dns_cache_is_empty(&s->cache)) { + fputs("CACHE:\n", f); + dns_cache_dump(&s->cache, f); + } +} + +DnsSearchDomain *dns_scope_get_search_domains(DnsScope *s) { + assert(s); + + if (s->protocol != DNS_PROTOCOL_DNS) + return NULL; + + if (s->link) + return s->link->search_domains; + + return s->manager->search_domains; +} + +bool dns_scope_name_needs_search_domain(DnsScope *s, const char *name) { + assert(s); + + if (s->protocol != DNS_PROTOCOL_DNS) + return false; + + return dns_name_is_single_label(name); +} + +bool dns_scope_network_good(DnsScope *s) { + /* Checks whether the network is in good state for lookups on this scope. For mDNS/LLMNR/Classic DNS scopes + * bound to links this is easy, as they don't even exist if the link isn't in a suitable state. For the global + * DNS scope we check whether there are any links that are up and have an address. */ + + if (s->link) + return true; + + return manager_routable(s->manager, AF_UNSPEC); +} + +int dns_scope_ifindex(DnsScope *s) { + assert(s); + + if (s->link) + return s->link->ifindex; + + return 0; +} diff --git a/src/grp-resolve/systemd-resolved/resolved-dns-scope.h b/src/grp-resolve/systemd-resolved/resolved-dns-scope.h new file mode 100644 index 0000000000..26623b1878 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-dns-scope.h @@ -0,0 +1,114 @@ +#pragma once + +/*** + This file is part of systemd. + + Copyright 2014 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include "basic-dns/resolved-dns-dnssec.h" +#include "basic-dns/resolved-dns-packet.h" +#include "systemd-basic/list.h" + +typedef struct DnsScope DnsScope; + +#include "resolved-dns-cache.h" +#include "resolved-dns-query.h" +#include "resolved-dns-search-domain.h" +#include "resolved-dns-server.h" +#include "resolved-dns-stream.h" +#include "resolved-dns-zone.h" +#include "resolved-link.h" + +typedef enum DnsScopeMatch { + DNS_SCOPE_NO, + DNS_SCOPE_MAYBE, + DNS_SCOPE_YES, + _DNS_SCOPE_MATCH_MAX, + _DNS_SCOPE_INVALID = -1 +} DnsScopeMatch; + +struct DnsScope { + Manager *manager; + + DnsProtocol protocol; + int family; + DnssecMode dnssec_mode; + + Link *link; + + DnsCache cache; + DnsZone zone; + + OrderedHashmap *conflict_queue; + sd_event_source *conflict_event_source; + + RateLimit ratelimit; + + usec_t resend_timeout; + usec_t max_rtt; + + LIST_HEAD(DnsQueryCandidate, query_candidates); + + /* Note that we keep track of ongoing transactions in two + * ways: once in a hashmap, indexed by the rr key, and once in + * a linked list. We use the hashmap to quickly find + * transactions we can reuse for a key. But note that there + * might be multiple transactions for the same key (because + * the zone probing can't reuse a transaction answered from + * the zone or the cache), and the hashmap only tracks the + * most recent entry. */ + Hashmap *transactions_by_key; + LIST_HEAD(DnsTransaction, transactions); + + LIST_FIELDS(DnsScope, scopes); +}; + +int dns_scope_new(Manager *m, DnsScope **ret, Link *l, DnsProtocol p, int family); +DnsScope* dns_scope_free(DnsScope *s); + +void dns_scope_packet_received(DnsScope *s, usec_t rtt); +void dns_scope_packet_lost(DnsScope *s, usec_t usec); + +int dns_scope_emit_udp(DnsScope *s, int fd, DnsPacket *p); +int dns_scope_socket_tcp(DnsScope *s, int family, const union in_addr_union *address, DnsServer *server, uint16_t port); +int dns_scope_socket_udp(DnsScope *s, DnsServer *server, uint16_t port); + +DnsScopeMatch dns_scope_good_domain(DnsScope *s, int ifindex, uint64_t flags, const char *domain); +bool dns_scope_good_key(DnsScope *s, const DnsResourceKey *key); + +DnsServer *dns_scope_get_dns_server(DnsScope *s); +void dns_scope_next_dns_server(DnsScope *s); + +int dns_scope_llmnr_membership(DnsScope *s, bool b); +int dns_scope_mdns_membership(DnsScope *s, bool b); + +void dns_scope_process_query(DnsScope *s, DnsStream *stream, DnsPacket *p); + +DnsTransaction *dns_scope_find_transaction(DnsScope *scope, DnsResourceKey *key, bool cache_ok); + +int dns_scope_notify_conflict(DnsScope *scope, DnsResourceRecord *rr); +void dns_scope_check_conflicts(DnsScope *scope, DnsPacket *p); + +void dns_scope_dump(DnsScope *s, FILE *f); + +DnsSearchDomain *dns_scope_get_search_domains(DnsScope *s); + +bool dns_scope_name_needs_search_domain(DnsScope *s, const char *name); + +bool dns_scope_network_good(DnsScope *s); + +int dns_scope_ifindex(DnsScope *s); diff --git a/src/grp-resolve/systemd-resolved/resolved-dns-search-domain.c b/src/grp-resolve/systemd-resolved/resolved-dns-search-domain.c new file mode 100644 index 0000000000..a82df4c7a6 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-dns-search-domain.c @@ -0,0 +1,226 @@ +/*** + This file is part of systemd. + + Copyright 2015 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include "systemd-basic/alloc-util.h" +#include "systemd-shared/dns-domain.h" + +#include "resolved-dns-search-domain.h" + +int dns_search_domain_new( + Manager *m, + DnsSearchDomain **ret, + DnsSearchDomainType type, + Link *l, + const char *name) { + + _cleanup_free_ char *normalized = NULL; + DnsSearchDomain *d; + int r; + + assert(m); + assert((type == DNS_SEARCH_DOMAIN_LINK) == !!l); + assert(name); + + r = dns_name_normalize(name, &normalized); + if (r < 0) + return r; + + if (l) { + if (l->n_search_domains >= LINK_SEARCH_DOMAINS_MAX) + return -E2BIG; + } else { + if (m->n_search_domains >= MANAGER_SEARCH_DOMAINS_MAX) + return -E2BIG; + } + + d = new0(DnsSearchDomain, 1); + if (!d) + return -ENOMEM; + + d->n_ref = 1; + d->manager = m; + d->type = type; + d->name = normalized; + normalized = NULL; + + switch (type) { + + case DNS_SEARCH_DOMAIN_LINK: + d->link = l; + LIST_APPEND(domains, l->search_domains, d); + l->n_search_domains++; + break; + + case DNS_SERVER_SYSTEM: + LIST_APPEND(domains, m->search_domains, d); + m->n_search_domains++; + break; + + default: + assert_not_reached("Unknown search domain type"); + } + + d->linked = true; + + if (ret) + *ret = d; + + return 0; +} + +DnsSearchDomain* dns_search_domain_ref(DnsSearchDomain *d) { + if (!d) + return NULL; + + assert(d->n_ref > 0); + d->n_ref++; + + return d; +} + +DnsSearchDomain* dns_search_domain_unref(DnsSearchDomain *d) { + if (!d) + return NULL; + + assert(d->n_ref > 0); + d->n_ref--; + + if (d->n_ref > 0) + return NULL; + + free(d->name); + return mfree(d); +} + +void dns_search_domain_unlink(DnsSearchDomain *d) { + assert(d); + assert(d->manager); + + if (!d->linked) + return; + + switch (d->type) { + + case DNS_SEARCH_DOMAIN_LINK: + assert(d->link); + assert(d->link->n_search_domains > 0); + LIST_REMOVE(domains, d->link->search_domains, d); + d->link->n_search_domains--; + break; + + case DNS_SEARCH_DOMAIN_SYSTEM: + assert(d->manager->n_search_domains > 0); + LIST_REMOVE(domains, d->manager->search_domains, d); + d->manager->n_search_domains--; + break; + } + + d->linked = false; + + dns_search_domain_unref(d); +} + +void dns_search_domain_move_back_and_unmark(DnsSearchDomain *d) { + DnsSearchDomain *tail; + + assert(d); + + if (!d->marked) + return; + + d->marked = false; + + if (!d->linked || !d->domains_next) + return; + + switch (d->type) { + + case DNS_SEARCH_DOMAIN_LINK: + assert(d->link); + LIST_FIND_TAIL(domains, d, tail); + LIST_REMOVE(domains, d->link->search_domains, d); + LIST_INSERT_AFTER(domains, d->link->search_domains, tail, d); + break; + + case DNS_SEARCH_DOMAIN_SYSTEM: + LIST_FIND_TAIL(domains, d, tail); + LIST_REMOVE(domains, d->manager->search_domains, d); + LIST_INSERT_AFTER(domains, d->manager->search_domains, tail, d); + break; + + default: + assert_not_reached("Unknown search domain type"); + } +} + +void dns_search_domain_unlink_all(DnsSearchDomain *first) { + DnsSearchDomain *next; + + if (!first) + return; + + next = first->domains_next; + dns_search_domain_unlink(first); + + dns_search_domain_unlink_all(next); +} + +void dns_search_domain_unlink_marked(DnsSearchDomain *first) { + DnsSearchDomain *next; + + if (!first) + return; + + next = first->domains_next; + + if (first->marked) + dns_search_domain_unlink(first); + + dns_search_domain_unlink_marked(next); +} + +void dns_search_domain_mark_all(DnsSearchDomain *first) { + if (!first) + return; + + first->marked = true; + dns_search_domain_mark_all(first->domains_next); +} + +int dns_search_domain_find(DnsSearchDomain *first, const char *name, DnsSearchDomain **ret) { + DnsSearchDomain *d; + int r; + + assert(name); + assert(ret); + + LIST_FOREACH(domains, d, first) { + + r = dns_name_equal(name, d->name); + if (r < 0) + return r; + if (r > 0) { + *ret = d; + return 1; + } + } + + *ret = NULL; + return 0; +} diff --git a/src/grp-resolve/systemd-resolved/resolved-dns-search-domain.h b/src/grp-resolve/systemd-resolved/resolved-dns-search-domain.h new file mode 100644 index 0000000000..53b4f3207a --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-dns-search-domain.h @@ -0,0 +1,74 @@ +#pragma once + +/*** + This file is part of systemd. + + Copyright 2015 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include "systemd-basic/macro.h" + +typedef struct DnsSearchDomain DnsSearchDomain; + +typedef enum DnsSearchDomainType { + DNS_SEARCH_DOMAIN_SYSTEM, + DNS_SEARCH_DOMAIN_LINK, +} DnsSearchDomainType; + +#include "resolved-link.h" +#include "resolved-manager.h" + +struct DnsSearchDomain { + Manager *manager; + + unsigned n_ref; + + DnsSearchDomainType type; + Link *link; + + char *name; + + bool marked:1; + bool route_only:1; + + bool linked:1; + LIST_FIELDS(DnsSearchDomain, domains); +}; + +int dns_search_domain_new( + Manager *m, + DnsSearchDomain **ret, + DnsSearchDomainType type, + Link *link, + const char *name); + +DnsSearchDomain* dns_search_domain_ref(DnsSearchDomain *d); +DnsSearchDomain* dns_search_domain_unref(DnsSearchDomain *d); + +void dns_search_domain_unlink(DnsSearchDomain *d); +void dns_search_domain_move_back_and_unmark(DnsSearchDomain *d); + +void dns_search_domain_unlink_all(DnsSearchDomain *first); +void dns_search_domain_unlink_marked(DnsSearchDomain *first); +void dns_search_domain_mark_all(DnsSearchDomain *first); + +int dns_search_domain_find(DnsSearchDomain *first, const char *name, DnsSearchDomain **ret); + +static inline const char* DNS_SEARCH_DOMAIN_NAME(DnsSearchDomain *d) { + return d ? d->name : NULL; +} + +DEFINE_TRIVIAL_CLEANUP_FUNC(DnsSearchDomain*, dns_search_domain_unref); diff --git a/src/grp-resolve/systemd-resolved/resolved-dns-server.c b/src/grp-resolve/systemd-resolved/resolved-dns-server.c new file mode 100644 index 0000000000..b2605c0d46 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-dns-server.c @@ -0,0 +1,797 @@ +/*** + This file is part of systemd. + + Copyright 2014 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include <systemd/sd-messages.h> + +#include "systemd-basic/alloc-util.h" +#include "systemd-basic/siphash24.h" +#include "systemd-basic/string-table.h" +#include "systemd-basic/string-util.h" + +#include "resolved-dns-server.h" +#include "resolved-dns-stub.h" +#include "resolved-resolv-conf.h" + +/* After how much time to repeat classic DNS requests */ +#define DNS_TIMEOUT_MIN_USEC (500 * USEC_PER_MSEC) +#define DNS_TIMEOUT_MAX_USEC (5 * USEC_PER_SEC) + +/* The amount of time to wait before retrying with a full feature set */ +#define DNS_SERVER_FEATURE_GRACE_PERIOD_MAX_USEC (6 * USEC_PER_HOUR) +#define DNS_SERVER_FEATURE_GRACE_PERIOD_MIN_USEC (5 * USEC_PER_MINUTE) + +/* The number of times we will attempt a certain feature set before degrading */ +#define DNS_SERVER_FEATURE_RETRY_ATTEMPTS 3 + +int dns_server_new( + Manager *m, + DnsServer **ret, + DnsServerType type, + Link *l, + int family, + const union in_addr_union *in_addr, + int ifindex) { + + DnsServer *s; + + assert(m); + assert((type == DNS_SERVER_LINK) == !!l); + assert(in_addr); + + if (!IN_SET(family, AF_INET, AF_INET6)) + return -EAFNOSUPPORT; + + if (l) { + if (l->n_dns_servers >= LINK_DNS_SERVERS_MAX) + return -E2BIG; + } else { + if (m->n_dns_servers >= MANAGER_DNS_SERVERS_MAX) + return -E2BIG; + } + + s = new0(DnsServer, 1); + if (!s) + return -ENOMEM; + + s->n_ref = 1; + s->manager = m; + s->verified_feature_level = _DNS_SERVER_FEATURE_LEVEL_INVALID; + s->possible_feature_level = DNS_SERVER_FEATURE_LEVEL_BEST; + s->features_grace_period_usec = DNS_SERVER_FEATURE_GRACE_PERIOD_MIN_USEC; + s->received_udp_packet_max = DNS_PACKET_UNICAST_SIZE_MAX; + s->type = type; + s->family = family; + s->address = *in_addr; + s->ifindex = ifindex; + s->resend_timeout = DNS_TIMEOUT_MIN_USEC; + + switch (type) { + + case DNS_SERVER_LINK: + s->link = l; + LIST_APPEND(servers, l->dns_servers, s); + l->n_dns_servers++; + break; + + case DNS_SERVER_SYSTEM: + LIST_APPEND(servers, m->dns_servers, s); + m->n_dns_servers++; + break; + + case DNS_SERVER_FALLBACK: + LIST_APPEND(servers, m->fallback_dns_servers, s); + m->n_dns_servers++; + break; + + default: + assert_not_reached("Unknown server type"); + } + + s->linked = true; + + /* A new DNS server that isn't fallback is added and the one + * we used so far was a fallback one? Then let's try to pick + * the new one */ + if (type != DNS_SERVER_FALLBACK && + m->current_dns_server && + m->current_dns_server->type == DNS_SERVER_FALLBACK) + manager_set_dns_server(m, NULL); + + if (ret) + *ret = s; + + return 0; +} + +DnsServer* dns_server_ref(DnsServer *s) { + if (!s) + return NULL; + + assert(s->n_ref > 0); + s->n_ref++; + + return s; +} + +DnsServer* dns_server_unref(DnsServer *s) { + if (!s) + return NULL; + + assert(s->n_ref > 0); + s->n_ref--; + + if (s->n_ref > 0) + return NULL; + + free(s->server_string); + return mfree(s); +} + +void dns_server_unlink(DnsServer *s) { + assert(s); + assert(s->manager); + + /* This removes the specified server from the linked list of + * servers, but any server might still stay around if it has + * refs, for example from an ongoing transaction. */ + + if (!s->linked) + return; + + switch (s->type) { + + case DNS_SERVER_LINK: + assert(s->link); + assert(s->link->n_dns_servers > 0); + LIST_REMOVE(servers, s->link->dns_servers, s); + s->link->n_dns_servers--; + break; + + case DNS_SERVER_SYSTEM: + assert(s->manager->n_dns_servers > 0); + LIST_REMOVE(servers, s->manager->dns_servers, s); + s->manager->n_dns_servers--; + break; + + case DNS_SERVER_FALLBACK: + assert(s->manager->n_dns_servers > 0); + LIST_REMOVE(servers, s->manager->fallback_dns_servers, s); + s->manager->n_dns_servers--; + break; + } + + s->linked = false; + + if (s->link && s->link->current_dns_server == s) + link_set_dns_server(s->link, NULL); + + if (s->manager->current_dns_server == s) + manager_set_dns_server(s->manager, NULL); + + dns_server_unref(s); +} + +void dns_server_move_back_and_unmark(DnsServer *s) { + DnsServer *tail; + + assert(s); + + if (!s->marked) + return; + + s->marked = false; + + if (!s->linked || !s->servers_next) + return; + + /* Move us to the end of the list, so that the order is + * strictly kept, if we are not at the end anyway. */ + + switch (s->type) { + + case DNS_SERVER_LINK: + assert(s->link); + LIST_FIND_TAIL(servers, s, tail); + LIST_REMOVE(servers, s->link->dns_servers, s); + LIST_INSERT_AFTER(servers, s->link->dns_servers, tail, s); + break; + + case DNS_SERVER_SYSTEM: + LIST_FIND_TAIL(servers, s, tail); + LIST_REMOVE(servers, s->manager->dns_servers, s); + LIST_INSERT_AFTER(servers, s->manager->dns_servers, tail, s); + break; + + case DNS_SERVER_FALLBACK: + LIST_FIND_TAIL(servers, s, tail); + LIST_REMOVE(servers, s->manager->fallback_dns_servers, s); + LIST_INSERT_AFTER(servers, s->manager->fallback_dns_servers, tail, s); + break; + + default: + assert_not_reached("Unknown server type"); + } +} + +static void dns_server_verified(DnsServer *s, DnsServerFeatureLevel level) { + assert(s); + + if (s->verified_feature_level > level) + return; + + if (s->verified_feature_level != level) { + log_debug("Verified we get a response at feature level %s from DNS server %s.", + dns_server_feature_level_to_string(level), + dns_server_string(s)); + s->verified_feature_level = level; + } + + assert_se(sd_event_now(s->manager->event, clock_boottime_or_monotonic(), &s->verified_usec) >= 0); +} + +static void dns_server_reset_counters(DnsServer *s) { + assert(s); + + s->n_failed_udp = 0; + s->n_failed_tcp = 0; + s->packet_truncated = false; + s->verified_usec = 0; + + /* Note that we do not reset s->packet_bad_opt and s->packet_rrsig_missing here. We reset them only when the + * grace period ends, but not when lowering the possible feature level, as a lower level feature level should + * not make RRSIGs appear or OPT appear, but rather make them disappear. If the reappear anyway, then that's + * indication for a differently broken OPT/RRSIG implementation, and we really don't want to support that + * either. + * + * This is particularly important to deal with certain Belkin routers which break OPT for certain lookups (A), + * but pass traffic through for others (AAAA). If we detect the broken behaviour on one lookup we should not + * reenable it for another, because we cannot validate things anyway, given that the RRSIG/OPT data will be + * incomplete. */ +} + +void dns_server_packet_received(DnsServer *s, int protocol, DnsServerFeatureLevel level, usec_t rtt, size_t size) { + assert(s); + + if (protocol == IPPROTO_UDP) { + if (s->possible_feature_level == level) + s->n_failed_udp = 0; + + /* If the RRSIG data is missing, then we can only validate EDNS0 at max */ + if (s->packet_rrsig_missing && level >= DNS_SERVER_FEATURE_LEVEL_DO) + level = DNS_SERVER_FEATURE_LEVEL_DO - 1; + + /* If the OPT RR got lost, then we can only validate UDP at max */ + if (s->packet_bad_opt && level >= DNS_SERVER_FEATURE_LEVEL_EDNS0) + level = DNS_SERVER_FEATURE_LEVEL_EDNS0 - 1; + + /* Even if we successfully receive a reply to a request announcing support for large packets, + that does not mean we can necessarily receive large packets. */ + if (level == DNS_SERVER_FEATURE_LEVEL_LARGE) + level = DNS_SERVER_FEATURE_LEVEL_LARGE - 1; + + } else if (protocol == IPPROTO_TCP) { + + if (s->possible_feature_level == level) + s->n_failed_tcp = 0; + + /* Successful TCP connections are only useful to verify the TCP feature level. */ + level = DNS_SERVER_FEATURE_LEVEL_TCP; + } + + dns_server_verified(s, level); + + /* Remember the size of the largest UDP packet we received from a server, + we know that we can always announce support for packets with at least + this size. */ + if (protocol == IPPROTO_UDP && s->received_udp_packet_max < size) + s->received_udp_packet_max = size; + + if (s->max_rtt < rtt) { + s->max_rtt = rtt; + s->resend_timeout = CLAMP(s->max_rtt * 2, DNS_TIMEOUT_MIN_USEC, DNS_TIMEOUT_MAX_USEC); + } +} + +void dns_server_packet_lost(DnsServer *s, int protocol, DnsServerFeatureLevel level, usec_t usec) { + assert(s); + assert(s->manager); + + if (s->possible_feature_level == level) { + if (protocol == IPPROTO_UDP) + s->n_failed_udp++; + else if (protocol == IPPROTO_TCP) + s->n_failed_tcp++; + } + + if (s->resend_timeout > usec) + return; + + s->resend_timeout = MIN(s->resend_timeout * 2, DNS_TIMEOUT_MAX_USEC); +} + +void dns_server_packet_truncated(DnsServer *s, DnsServerFeatureLevel level) { + assert(s); + + /* Invoked whenever we get a packet with TC bit set. */ + + if (s->possible_feature_level != level) + return; + + s->packet_truncated = true; +} + +void dns_server_packet_rrsig_missing(DnsServer *s, DnsServerFeatureLevel level) { + assert(s); + + if (level < DNS_SERVER_FEATURE_LEVEL_DO) + return; + + /* If the RRSIG RRs are missing, we have to downgrade what we previously verified */ + if (s->verified_feature_level >= DNS_SERVER_FEATURE_LEVEL_DO) + s->verified_feature_level = DNS_SERVER_FEATURE_LEVEL_DO-1; + + s->packet_rrsig_missing = true; +} + +void dns_server_packet_bad_opt(DnsServer *s, DnsServerFeatureLevel level) { + assert(s); + + if (level < DNS_SERVER_FEATURE_LEVEL_EDNS0) + return; + + /* If the OPT RR got lost, we have to downgrade what we previously verified */ + if (s->verified_feature_level >= DNS_SERVER_FEATURE_LEVEL_EDNS0) + s->verified_feature_level = DNS_SERVER_FEATURE_LEVEL_EDNS0-1; + + s->packet_bad_opt = true; +} + +void dns_server_packet_rcode_downgrade(DnsServer *s, DnsServerFeatureLevel level) { + assert(s); + + /* Invoked whenever we got a FORMERR, SERVFAIL or NOTIMP rcode from a server and downgrading the feature level + * for the transaction made it go away. In this case we immediately downgrade to the feature level that made + * things work. */ + + if (s->verified_feature_level > level) + s->verified_feature_level = level; + + if (s->possible_feature_level > level) { + s->possible_feature_level = level; + dns_server_reset_counters(s); + } + + log_debug("Downgrading transaction feature level fixed an RCODE error, downgrading server %s too.", dns_server_string(s)); +} + +static bool dns_server_grace_period_expired(DnsServer *s) { + usec_t ts; + + assert(s); + assert(s->manager); + + if (s->verified_usec == 0) + return false; + + assert_se(sd_event_now(s->manager->event, clock_boottime_or_monotonic(), &ts) >= 0); + + if (s->verified_usec + s->features_grace_period_usec > ts) + return false; + + s->features_grace_period_usec = MIN(s->features_grace_period_usec * 2, DNS_SERVER_FEATURE_GRACE_PERIOD_MAX_USEC); + + return true; +} + +DnsServerFeatureLevel dns_server_possible_feature_level(DnsServer *s) { + assert(s); + + if (s->possible_feature_level != DNS_SERVER_FEATURE_LEVEL_BEST && + dns_server_grace_period_expired(s)) { + + s->possible_feature_level = DNS_SERVER_FEATURE_LEVEL_BEST; + + dns_server_reset_counters(s); + + s->packet_bad_opt = false; + s->packet_rrsig_missing = false; + + log_info("Grace period over, resuming full feature set (%s) for DNS server %s.", + dns_server_feature_level_to_string(s->possible_feature_level), + dns_server_string(s)); + + } else if (s->possible_feature_level <= s->verified_feature_level) + s->possible_feature_level = s->verified_feature_level; + else { + DnsServerFeatureLevel p = s->possible_feature_level; + + if (s->n_failed_tcp >= DNS_SERVER_FEATURE_RETRY_ATTEMPTS && + s->possible_feature_level == DNS_SERVER_FEATURE_LEVEL_TCP) { + + /* We are at the TCP (lowest) level, and we tried a couple of TCP connections, and it didn't + * work. Upgrade back to UDP again. */ + log_debug("Reached maximum number of failed TCP connection attempts, trying UDP again..."); + s->possible_feature_level = DNS_SERVER_FEATURE_LEVEL_UDP; + + } else if (s->packet_bad_opt && + s->possible_feature_level >= DNS_SERVER_FEATURE_LEVEL_EDNS0) { + + /* A reply to one of our EDNS0 queries didn't carry a valid OPT RR, then downgrade to below + * EDNS0 levels. After all, some records generate different responses with and without OPT RR + * in the request. Example: + * https://open.nlnetlabs.nl/pipermail/dnssec-trigger/2014-November/000376.html */ + + log_debug("Server doesn't support EDNS(0) properly, downgrading feature level..."); + s->possible_feature_level = DNS_SERVER_FEATURE_LEVEL_UDP; + + } else if (s->packet_rrsig_missing && + s->possible_feature_level >= DNS_SERVER_FEATURE_LEVEL_DO) { + + /* RRSIG data was missing on a EDNS0 packet with DO bit set. This means the server doesn't + * augment responses with DNSSEC RRs. If so, let's better not ask the server for it anymore, + * after all some servers generate different replies depending if an OPT RR is in the query or + * not. */ + + log_debug("Detected server responses lack RRSIG records, downgrading feature level..."); + s->possible_feature_level = DNS_SERVER_FEATURE_LEVEL_EDNS0; + + } else if (s->n_failed_udp >= DNS_SERVER_FEATURE_RETRY_ATTEMPTS && + s->possible_feature_level >= DNS_SERVER_FEATURE_LEVEL_UDP) { + + /* We lost too many UDP packets in a row, and are on a feature level of UDP or higher. If the + * packets are lost, maybe the server cannot parse them, hence downgrading sounds like a good + * idea. We might downgrade all the way down to TCP this way. */ + + log_debug("Lost too many UDP packets, downgrading feature level..."); + s->possible_feature_level--; + + } else if (s->n_failed_tcp >= DNS_SERVER_FEATURE_RETRY_ATTEMPTS && + s->packet_truncated && + s->possible_feature_level > DNS_SERVER_FEATURE_LEVEL_UDP) { + + /* We got too many TCP connection failures in a row, we had at least one truncated packet, and + * are on a feature level above UDP. By downgrading things and getting rid of DNSSEC or EDNS0 + * data we hope to make the packet smaller, so that it still works via UDP given that TCP + * appears not to be a fallback. Note that if we are already at the lowest UDP level, we don't + * go further down, since that's TCP, and TCP failed too often after all. */ + + log_debug("Got too many failed TCP connection failures and truncated UDP packets, downgrading feature level..."); + s->possible_feature_level--; + } + + if (p != s->possible_feature_level) { + + /* We changed the feature level, reset the counting */ + dns_server_reset_counters(s); + + log_warning("Using degraded feature set (%s) for DNS server %s.", + dns_server_feature_level_to_string(s->possible_feature_level), + dns_server_string(s)); + } + } + + return s->possible_feature_level; +} + +int dns_server_adjust_opt(DnsServer *server, DnsPacket *packet, DnsServerFeatureLevel level) { + size_t packet_size; + bool edns_do; + int r; + + assert(server); + assert(packet); + assert(packet->protocol == DNS_PROTOCOL_DNS); + + /* Fix the OPT field in the packet to match our current feature level. */ + + r = dns_packet_truncate_opt(packet); + if (r < 0) + return r; + + if (level < DNS_SERVER_FEATURE_LEVEL_EDNS0) + return 0; + + edns_do = level >= DNS_SERVER_FEATURE_LEVEL_DO; + + if (level >= DNS_SERVER_FEATURE_LEVEL_LARGE) + packet_size = DNS_PACKET_UNICAST_SIZE_LARGE_MAX; + else + packet_size = server->received_udp_packet_max; + + return dns_packet_append_opt(packet, packet_size, edns_do, 0, NULL); +} + +int dns_server_ifindex(const DnsServer *s) { + assert(s); + + /* The link ifindex always takes precedence */ + if (s->link) + return s->link->ifindex; + + if (s->ifindex > 0) + return s->ifindex; + + return 0; +} + +const char *dns_server_string(DnsServer *server) { + assert(server); + + if (!server->server_string) + (void) in_addr_ifindex_to_string(server->family, &server->address, dns_server_ifindex(server), &server->server_string); + + return strna(server->server_string); +} + +bool dns_server_dnssec_supported(DnsServer *server) { + assert(server); + + /* Returns whether the server supports DNSSEC according to what we know about it */ + + if (server->possible_feature_level < DNS_SERVER_FEATURE_LEVEL_DO) + return false; + + if (server->packet_bad_opt) + return false; + + if (server->packet_rrsig_missing) + return false; + + /* DNSSEC servers need to support TCP properly (see RFC5966), if they don't, we assume DNSSEC is borked too */ + if (server->n_failed_tcp >= DNS_SERVER_FEATURE_RETRY_ATTEMPTS) + return false; + + return true; +} + +void dns_server_warn_downgrade(DnsServer *server) { + assert(server); + + if (server->warned_downgrade) + return; + + log_struct(LOG_NOTICE, + LOG_MESSAGE_ID(SD_MESSAGE_DNSSEC_DOWNGRADE), + LOG_MESSAGE("Server %s does not support DNSSEC, downgrading to non-DNSSEC mode.", dns_server_string(server)), + "DNS_SERVER=%s", dns_server_string(server), + "DNS_SERVER_FEATURE_LEVEL=%s", dns_server_feature_level_to_string(server->possible_feature_level), + NULL); + + server->warned_downgrade = true; +} + +bool dns_server_limited_domains(DnsServer *server) { + DnsSearchDomain *domain; + bool domain_restricted = false; + + /* Check if the server has route-only domains without ~., i. e. whether + * it should only be used for particular domains */ + if (!server->link) + return false; + + LIST_FOREACH(domains, domain, server->link->search_domains) + if (domain->route_only) { + domain_restricted = true; + /* ~. means "any domain", thus it is a global server */ + if (dns_name_is_root(DNS_SEARCH_DOMAIN_NAME(domain))) + return false; + } + + return domain_restricted; +} + +static void dns_server_hash_func(const void *p, struct siphash *state) { + const DnsServer *s = p; + + assert(s); + + siphash24_compress(&s->family, sizeof(s->family), state); + siphash24_compress(&s->address, FAMILY_ADDRESS_SIZE(s->family), state); + siphash24_compress(&s->ifindex, sizeof(s->ifindex), state); +} + +static int dns_server_compare_func(const void *a, const void *b) { + const DnsServer *x = a, *y = b; + int r; + + if (x->family < y->family) + return -1; + if (x->family > y->family) + return 1; + + r = memcmp(&x->address, &y->address, FAMILY_ADDRESS_SIZE(x->family)); + if (r != 0) + return r; + + if (x->ifindex < y->ifindex) + return -1; + if (x->ifindex > y->ifindex) + return 1; + + return 0; +} + +const struct hash_ops dns_server_hash_ops = { + .hash = dns_server_hash_func, + .compare = dns_server_compare_func +}; + +void dns_server_unlink_all(DnsServer *first) { + DnsServer *next; + + if (!first) + return; + + next = first->servers_next; + dns_server_unlink(first); + + dns_server_unlink_all(next); +} + +void dns_server_unlink_marked(DnsServer *first) { + DnsServer *next; + + if (!first) + return; + + next = first->servers_next; + + if (first->marked) + dns_server_unlink(first); + + dns_server_unlink_marked(next); +} + +void dns_server_mark_all(DnsServer *first) { + if (!first) + return; + + first->marked = true; + dns_server_mark_all(first->servers_next); +} + +DnsServer *dns_server_find(DnsServer *first, int family, const union in_addr_union *in_addr, int ifindex) { + DnsServer *s; + + LIST_FOREACH(servers, s, first) + if (s->family == family && in_addr_equal(family, &s->address, in_addr) > 0 && s->ifindex == ifindex) + return s; + + return NULL; +} + +DnsServer *manager_get_first_dns_server(Manager *m, DnsServerType t) { + assert(m); + + switch (t) { + + case DNS_SERVER_SYSTEM: + return m->dns_servers; + + case DNS_SERVER_FALLBACK: + return m->fallback_dns_servers; + + default: + return NULL; + } +} + +DnsServer *manager_set_dns_server(Manager *m, DnsServer *s) { + assert(m); + + if (m->current_dns_server == s) + return s; + + if (s) + log_info("Switching to %s DNS server %s.", + dns_server_type_to_string(s->type), + dns_server_string(s)); + + dns_server_unref(m->current_dns_server); + m->current_dns_server = dns_server_ref(s); + + if (m->unicast_scope) + dns_cache_flush(&m->unicast_scope->cache); + + return s; +} + +DnsServer *manager_get_dns_server(Manager *m) { + Link *l; + assert(m); + + /* Try to read updates resolv.conf */ + manager_read_resolv_conf(m); + + /* If no DNS server was chosen so far, pick the first one */ + if (!m->current_dns_server) + manager_set_dns_server(m, m->dns_servers); + + if (!m->current_dns_server) { + bool found = false; + Iterator i; + + /* No DNS servers configured, let's see if there are + * any on any links. If not, we use the fallback + * servers */ + + HASHMAP_FOREACH(l, m->links, i) + if (l->dns_servers) { + found = true; + break; + } + + if (!found) + manager_set_dns_server(m, m->fallback_dns_servers); + } + + return m->current_dns_server; +} + +void manager_next_dns_server(Manager *m) { + assert(m); + + /* If there's currently no DNS server set, then the next + * manager_get_dns_server() will find one */ + if (!m->current_dns_server) + return; + + /* Change to the next one, but make sure to follow the linked + * list only if the server is still linked. */ + if (m->current_dns_server->linked && m->current_dns_server->servers_next) { + manager_set_dns_server(m, m->current_dns_server->servers_next); + return; + } + + /* If there was no next one, then start from the beginning of + * the list */ + if (m->current_dns_server->type == DNS_SERVER_FALLBACK) + manager_set_dns_server(m, m->fallback_dns_servers); + else + manager_set_dns_server(m, m->dns_servers); +} + +bool dns_server_address_valid(int family, const union in_addr_union *sa) { + + /* Refuses the 0 IP addresses as well as 127.0.0.53 (which is our own DNS stub) */ + + if (in_addr_is_null(family, sa)) + return false; + + if (family == AF_INET && sa->in.s_addr == htobe32(INADDR_DNS_STUB)) + return false; + + return true; +} + +static const char* const dns_server_type_table[_DNS_SERVER_TYPE_MAX] = { + [DNS_SERVER_SYSTEM] = "system", + [DNS_SERVER_FALLBACK] = "fallback", + [DNS_SERVER_LINK] = "link", +}; +DEFINE_STRING_TABLE_LOOKUP(dns_server_type, DnsServerType); + +static const char* const dns_server_feature_level_table[_DNS_SERVER_FEATURE_LEVEL_MAX] = { + [DNS_SERVER_FEATURE_LEVEL_TCP] = "TCP", + [DNS_SERVER_FEATURE_LEVEL_UDP] = "UDP", + [DNS_SERVER_FEATURE_LEVEL_EDNS0] = "UDP+EDNS0", + [DNS_SERVER_FEATURE_LEVEL_DO] = "UDP+EDNS0+DO", + [DNS_SERVER_FEATURE_LEVEL_LARGE] = "UDP+EDNS0+DO+LARGE", +}; +DEFINE_STRING_TABLE_LOOKUP(dns_server_feature_level, DnsServerFeatureLevel); diff --git a/src/grp-resolve/systemd-resolved/resolved-dns-server.h b/src/grp-resolve/systemd-resolved/resolved-dns-server.h new file mode 100644 index 0000000000..cb0ad80292 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-dns-server.h @@ -0,0 +1,149 @@ +#pragma once + +/*** + This file is part of systemd. + + Copyright 2014 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include "systemd-basic/in-addr-util.h" + +typedef struct DnsServer DnsServer; + +typedef enum DnsServerType { + DNS_SERVER_SYSTEM, + DNS_SERVER_FALLBACK, + DNS_SERVER_LINK, +} DnsServerType; +#define _DNS_SERVER_TYPE_MAX (DNS_SERVER_LINK + 1) + +const char* dns_server_type_to_string(DnsServerType i) _const_; +DnsServerType dns_server_type_from_string(const char *s) _pure_; + +typedef enum DnsServerFeatureLevel { + DNS_SERVER_FEATURE_LEVEL_TCP, + DNS_SERVER_FEATURE_LEVEL_UDP, + DNS_SERVER_FEATURE_LEVEL_EDNS0, + DNS_SERVER_FEATURE_LEVEL_DO, + DNS_SERVER_FEATURE_LEVEL_LARGE, + _DNS_SERVER_FEATURE_LEVEL_MAX, + _DNS_SERVER_FEATURE_LEVEL_INVALID = -1 +} DnsServerFeatureLevel; + +#define DNS_SERVER_FEATURE_LEVEL_WORST 0 +#define DNS_SERVER_FEATURE_LEVEL_BEST (_DNS_SERVER_FEATURE_LEVEL_MAX - 1) + +const char* dns_server_feature_level_to_string(int i) _const_; +int dns_server_feature_level_from_string(const char *s) _pure_; + +#include "resolved-link.h" +#include "resolved-manager.h" + +struct DnsServer { + Manager *manager; + + unsigned n_ref; + + DnsServerType type; + Link *link; + + int family; + union in_addr_union address; + int ifindex; /* for IPv6 link-local DNS servers */ + + char *server_string; + + usec_t resend_timeout; + usec_t max_rtt; + + DnsServerFeatureLevel verified_feature_level; + DnsServerFeatureLevel possible_feature_level; + + size_t received_udp_packet_max; + + unsigned n_failed_udp; + unsigned n_failed_tcp; + + bool packet_truncated:1; + bool packet_bad_opt:1; + bool packet_rrsig_missing:1; + + usec_t verified_usec; + usec_t features_grace_period_usec; + + /* Whether we already warned about downgrading to non-DNSSEC mode for this server */ + bool warned_downgrade:1; + + /* Used when GC'ing old DNS servers when configuration changes. */ + bool marked:1; + + /* If linked is set, then this server appears in the servers linked list */ + bool linked:1; + LIST_FIELDS(DnsServer, servers); +}; + +int dns_server_new( + Manager *m, + DnsServer **ret, + DnsServerType type, + Link *link, + int family, + const union in_addr_union *address, + int ifindex); + +DnsServer* dns_server_ref(DnsServer *s); +DnsServer* dns_server_unref(DnsServer *s); + +void dns_server_unlink(DnsServer *s); +void dns_server_move_back_and_unmark(DnsServer *s); + +void dns_server_packet_received(DnsServer *s, int protocol, DnsServerFeatureLevel level, usec_t rtt, size_t size); +void dns_server_packet_lost(DnsServer *s, int protocol, DnsServerFeatureLevel level, usec_t usec); +void dns_server_packet_truncated(DnsServer *s, DnsServerFeatureLevel level); +void dns_server_packet_rrsig_missing(DnsServer *s, DnsServerFeatureLevel level); +void dns_server_packet_bad_opt(DnsServer *s, DnsServerFeatureLevel level); +void dns_server_packet_rcode_downgrade(DnsServer *s, DnsServerFeatureLevel level); + +DnsServerFeatureLevel dns_server_possible_feature_level(DnsServer *s); + +int dns_server_adjust_opt(DnsServer *server, DnsPacket *packet, DnsServerFeatureLevel level); + +const char *dns_server_string(DnsServer *server); +int dns_server_ifindex(const DnsServer *s); + +bool dns_server_dnssec_supported(DnsServer *server); + +void dns_server_warn_downgrade(DnsServer *server); + +bool dns_server_limited_domains(DnsServer *server); + +DnsServer *dns_server_find(DnsServer *first, int family, const union in_addr_union *in_addr, int ifindex); + +void dns_server_unlink_all(DnsServer *first); +void dns_server_unlink_marked(DnsServer *first); +void dns_server_mark_all(DnsServer *first); + +DnsServer *manager_get_first_dns_server(Manager *m, DnsServerType t); + +DnsServer *manager_set_dns_server(Manager *m, DnsServer *s); +DnsServer *manager_get_dns_server(Manager *m); +void manager_next_dns_server(Manager *m); + +bool dns_server_address_valid(int family, const union in_addr_union *sa); + +DEFINE_TRIVIAL_CLEANUP_FUNC(DnsServer*, dns_server_unref); + +extern const struct hash_ops dns_server_hash_ops; diff --git a/src/grp-resolve/systemd-resolved/resolved-dns-stream.c b/src/grp-resolve/systemd-resolved/resolved-dns-stream.c new file mode 100644 index 0000000000..5f77d47f64 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-dns-stream.c @@ -0,0 +1,419 @@ +/*** + This file is part of systemd. + + Copyright 2014 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include <netinet/tcp.h> + +#include "systemd-basic/alloc-util.h" +#include "systemd-basic/fd-util.h" +#include "systemd-basic/io-util.h" +#include "systemd-basic/missing.h" + +#include "resolved-dns-stream.h" + +#define DNS_STREAM_TIMEOUT_USEC (10 * USEC_PER_SEC) +#define DNS_STREAMS_MAX 128 + +static void dns_stream_stop(DnsStream *s) { + assert(s); + + s->io_event_source = sd_event_source_unref(s->io_event_source); + s->timeout_event_source = sd_event_source_unref(s->timeout_event_source); + s->fd = safe_close(s->fd); +} + +static int dns_stream_update_io(DnsStream *s) { + int f = 0; + + assert(s); + + if (s->write_packet && s->n_written < sizeof(s->write_size) + s->write_packet->size) + f |= EPOLLOUT; + if (!s->read_packet || s->n_read < sizeof(s->read_size) + s->read_packet->size) + f |= EPOLLIN; + + return sd_event_source_set_io_events(s->io_event_source, f); +} + +static int dns_stream_complete(DnsStream *s, int error) { + assert(s); + + dns_stream_stop(s); + + if (s->complete) + s->complete(s, error); + else /* the default action if no completion function is set is to close the stream */ + dns_stream_unref(s); + + return 0; +} + +static int dns_stream_identify(DnsStream *s) { + union { + struct cmsghdr header; /* For alignment */ + uint8_t buffer[CMSG_SPACE(MAXSIZE(struct in_pktinfo, struct in6_pktinfo)) + + EXTRA_CMSG_SPACE /* kernel appears to require extra space */]; + } control; + struct msghdr mh = {}; + struct cmsghdr *cmsg; + socklen_t sl; + int r; + + assert(s); + + if (s->identified) + return 0; + + /* Query the local side */ + s->local_salen = sizeof(s->local); + r = getsockname(s->fd, &s->local.sa, &s->local_salen); + if (r < 0) + return -errno; + if (s->local.sa.sa_family == AF_INET6 && s->ifindex <= 0) + s->ifindex = s->local.in6.sin6_scope_id; + + /* Query the remote side */ + s->peer_salen = sizeof(s->peer); + r = getpeername(s->fd, &s->peer.sa, &s->peer_salen); + if (r < 0) + return -errno; + if (s->peer.sa.sa_family == AF_INET6 && s->ifindex <= 0) + s->ifindex = s->peer.in6.sin6_scope_id; + + /* Check consistency */ + assert(s->peer.sa.sa_family == s->local.sa.sa_family); + assert(IN_SET(s->peer.sa.sa_family, AF_INET, AF_INET6)); + + /* Query connection meta information */ + sl = sizeof(control); + if (s->peer.sa.sa_family == AF_INET) { + r = getsockopt(s->fd, IPPROTO_IP, IP_PKTOPTIONS, &control, &sl); + if (r < 0) + return -errno; + } else if (s->peer.sa.sa_family == AF_INET6) { + + r = getsockopt(s->fd, IPPROTO_IPV6, IPV6_2292PKTOPTIONS, &control, &sl); + if (r < 0) + return -errno; + } else + return -EAFNOSUPPORT; + + mh.msg_control = &control; + mh.msg_controllen = sl; + + CMSG_FOREACH(cmsg, &mh) { + + if (cmsg->cmsg_level == IPPROTO_IPV6) { + assert(s->peer.sa.sa_family == AF_INET6); + + switch (cmsg->cmsg_type) { + + case IPV6_PKTINFO: { + struct in6_pktinfo *i = (struct in6_pktinfo*) CMSG_DATA(cmsg); + + if (s->ifindex <= 0) + s->ifindex = i->ipi6_ifindex; + break; + } + + case IPV6_HOPLIMIT: + s->ttl = *(int *) CMSG_DATA(cmsg); + break; + } + + } else if (cmsg->cmsg_level == IPPROTO_IP) { + assert(s->peer.sa.sa_family == AF_INET); + + switch (cmsg->cmsg_type) { + + case IP_PKTINFO: { + struct in_pktinfo *i = (struct in_pktinfo*) CMSG_DATA(cmsg); + + if (s->ifindex <= 0) + s->ifindex = i->ipi_ifindex; + break; + } + + case IP_TTL: + s->ttl = *(int *) CMSG_DATA(cmsg); + break; + } + } + } + + /* The Linux kernel sets the interface index to the loopback + * device if the connection came from the local host since it + * avoids the routing table in such a case. Let's unset the + * interface index in such a case. */ + if (s->ifindex == LOOPBACK_IFINDEX) + s->ifindex = 0; + + /* If we don't know the interface index still, we look for the + * first local interface with a matching address. Yuck! */ + if (s->ifindex <= 0) + s->ifindex = manager_find_ifindex(s->manager, s->local.sa.sa_family, s->local.sa.sa_family == AF_INET ? (union in_addr_union*) &s->local.in.sin_addr : (union in_addr_union*) &s->local.in6.sin6_addr); + + if (s->protocol == DNS_PROTOCOL_LLMNR && s->ifindex > 0) { + uint32_t ifindex = htobe32(s->ifindex); + + /* Make sure all packets for this connection are sent on the same interface */ + if (s->local.sa.sa_family == AF_INET) { + r = setsockopt(s->fd, IPPROTO_IP, IP_UNICAST_IF, &ifindex, sizeof(ifindex)); + if (r < 0) + log_debug_errno(errno, "Failed to invoke IP_UNICAST_IF: %m"); + } else if (s->local.sa.sa_family == AF_INET6) { + r = setsockopt(s->fd, IPPROTO_IPV6, IPV6_UNICAST_IF, &ifindex, sizeof(ifindex)); + if (r < 0) + log_debug_errno(errno, "Failed to invoke IPV6_UNICAST_IF: %m"); + } + } + + s->identified = true; + + return 0; +} + +static int on_stream_timeout(sd_event_source *es, usec_t usec, void *userdata) { + DnsStream *s = userdata; + + assert(s); + + return dns_stream_complete(s, ETIMEDOUT); +} + +static int on_stream_io(sd_event_source *es, int fd, uint32_t revents, void *userdata) { + DnsStream *s = userdata; + int r; + + assert(s); + + r = dns_stream_identify(s); + if (r < 0) + return dns_stream_complete(s, -r); + + if ((revents & EPOLLOUT) && + s->write_packet && + s->n_written < sizeof(s->write_size) + s->write_packet->size) { + + struct iovec iov[2]; + ssize_t ss; + + iov[0].iov_base = &s->write_size; + iov[0].iov_len = sizeof(s->write_size); + iov[1].iov_base = DNS_PACKET_DATA(s->write_packet); + iov[1].iov_len = s->write_packet->size; + + IOVEC_INCREMENT(iov, 2, s->n_written); + + ss = writev(fd, iov, 2); + if (ss < 0) { + if (errno != EINTR && errno != EAGAIN) + return dns_stream_complete(s, errno); + } else + s->n_written += ss; + + /* Are we done? If so, disable the event source for EPOLLOUT */ + if (s->n_written >= sizeof(s->write_size) + s->write_packet->size) { + r = dns_stream_update_io(s); + if (r < 0) + return dns_stream_complete(s, -r); + } + } + + if ((revents & (EPOLLIN|EPOLLHUP|EPOLLRDHUP)) && + (!s->read_packet || + s->n_read < sizeof(s->read_size) + s->read_packet->size)) { + + if (s->n_read < sizeof(s->read_size)) { + ssize_t ss; + + ss = read(fd, (uint8_t*) &s->read_size + s->n_read, sizeof(s->read_size) - s->n_read); + if (ss < 0) { + if (errno != EINTR && errno != EAGAIN) + return dns_stream_complete(s, errno); + } else if (ss == 0) + return dns_stream_complete(s, ECONNRESET); + else + s->n_read += ss; + } + + if (s->n_read >= sizeof(s->read_size)) { + + if (be16toh(s->read_size) < DNS_PACKET_HEADER_SIZE) + return dns_stream_complete(s, EBADMSG); + + if (s->n_read < sizeof(s->read_size) + be16toh(s->read_size)) { + ssize_t ss; + + if (!s->read_packet) { + r = dns_packet_new(&s->read_packet, s->protocol, be16toh(s->read_size)); + if (r < 0) + return dns_stream_complete(s, -r); + + s->read_packet->size = be16toh(s->read_size); + s->read_packet->ipproto = IPPROTO_TCP; + s->read_packet->family = s->peer.sa.sa_family; + s->read_packet->ttl = s->ttl; + s->read_packet->ifindex = s->ifindex; + + if (s->read_packet->family == AF_INET) { + s->read_packet->sender.in = s->peer.in.sin_addr; + s->read_packet->sender_port = be16toh(s->peer.in.sin_port); + s->read_packet->destination.in = s->local.in.sin_addr; + s->read_packet->destination_port = be16toh(s->local.in.sin_port); + } else { + assert(s->read_packet->family == AF_INET6); + s->read_packet->sender.in6 = s->peer.in6.sin6_addr; + s->read_packet->sender_port = be16toh(s->peer.in6.sin6_port); + s->read_packet->destination.in6 = s->local.in6.sin6_addr; + s->read_packet->destination_port = be16toh(s->local.in6.sin6_port); + + if (s->read_packet->ifindex == 0) + s->read_packet->ifindex = s->peer.in6.sin6_scope_id; + if (s->read_packet->ifindex == 0) + s->read_packet->ifindex = s->local.in6.sin6_scope_id; + } + } + + ss = read(fd, + (uint8_t*) DNS_PACKET_DATA(s->read_packet) + s->n_read - sizeof(s->read_size), + sizeof(s->read_size) + be16toh(s->read_size) - s->n_read); + if (ss < 0) { + if (errno != EINTR && errno != EAGAIN) + return dns_stream_complete(s, errno); + } else if (ss == 0) + return dns_stream_complete(s, ECONNRESET); + else + s->n_read += ss; + } + + /* Are we done? If so, disable the event source for EPOLLIN */ + if (s->n_read >= sizeof(s->read_size) + be16toh(s->read_size)) { + r = dns_stream_update_io(s); + if (r < 0) + return dns_stream_complete(s, -r); + + /* If there's a packet handler + * installed, call that. Note that + * this is optional... */ + if (s->on_packet) + return s->on_packet(s); + } + } + } + + if ((s->write_packet && s->n_written >= sizeof(s->write_size) + s->write_packet->size) && + (s->read_packet && s->n_read >= sizeof(s->read_size) + s->read_packet->size)) + return dns_stream_complete(s, 0); + + return 0; +} + +DnsStream *dns_stream_unref(DnsStream *s) { + if (!s) + return NULL; + + assert(s->n_ref > 0); + s->n_ref--; + + if (s->n_ref > 0) + return NULL; + + dns_stream_stop(s); + + if (s->manager) { + LIST_REMOVE(streams, s->manager->dns_streams, s); + s->manager->n_dns_streams--; + } + + dns_packet_unref(s->write_packet); + dns_packet_unref(s->read_packet); + + return mfree(s); +} + +DEFINE_TRIVIAL_CLEANUP_FUNC(DnsStream*, dns_stream_unref); + +DnsStream *dns_stream_ref(DnsStream *s) { + if (!s) + return NULL; + + assert(s->n_ref > 0); + s->n_ref++; + + return s; +} + +int dns_stream_new(Manager *m, DnsStream **ret, DnsProtocol protocol, int fd) { + _cleanup_(dns_stream_unrefp) DnsStream *s = NULL; + int r; + + assert(m); + assert(fd >= 0); + + if (m->n_dns_streams > DNS_STREAMS_MAX) + return -EBUSY; + + s = new0(DnsStream, 1); + if (!s) + return -ENOMEM; + + s->n_ref = 1; + s->fd = -1; + s->protocol = protocol; + + r = sd_event_add_io(m->event, &s->io_event_source, fd, EPOLLIN, on_stream_io, s); + if (r < 0) + return r; + + (void) sd_event_source_set_description(s->io_event_source, "dns-stream-io"); + + r = sd_event_add_time( + m->event, + &s->timeout_event_source, + clock_boottime_or_monotonic(), + now(clock_boottime_or_monotonic()) + DNS_STREAM_TIMEOUT_USEC, 0, + on_stream_timeout, s); + if (r < 0) + return r; + + (void) sd_event_source_set_description(s->timeout_event_source, "dns-stream-timeout"); + + LIST_PREPEND(streams, m->dns_streams, s); + s->manager = m; + s->fd = fd; + m->n_dns_streams++; + + *ret = s; + s = NULL; + + return 0; +} + +int dns_stream_write_packet(DnsStream *s, DnsPacket *p) { + assert(s); + + if (s->write_packet) + return -EBUSY; + + s->write_packet = dns_packet_ref(p); + s->write_size = htobe16(p->size); + s->n_written = 0; + + return dns_stream_update_io(s); +} diff --git a/src/grp-resolve/systemd-resolved/resolved-dns-stream.h b/src/grp-resolve/systemd-resolved/resolved-dns-stream.h new file mode 100644 index 0000000000..3d5a3c22d1 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-dns-stream.h @@ -0,0 +1,81 @@ +#pragma once + +/*** + This file is part of systemd. + + Copyright 2014 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include "basic-dns/resolved-dns-packet.h" +#include "systemd-basic/socket-util.h" + +typedef struct DnsStream DnsStream; + +#include "resolved-dns-transaction.h" +#include "resolved-manager.h" + +/* Streams are used by three subsystems: + * + * 1. The normal transaction logic when doing a DNS or LLMNR lookup via TCP + * 2. The LLMNR logic when accepting a TCP-based lookup + * 3. The DNS stub logic when accepting a TCP-based lookup + */ + +struct DnsStream { + Manager *manager; + int n_ref; + + DnsProtocol protocol; + + int fd; + union sockaddr_union peer; + socklen_t peer_salen; + union sockaddr_union local; + socklen_t local_salen; + int ifindex; + uint32_t ttl; + bool identified; + + sd_event_source *io_event_source; + sd_event_source *timeout_event_source; + + be16_t write_size, read_size; + DnsPacket *write_packet, *read_packet; + size_t n_written, n_read; + + int (*on_packet)(DnsStream *s); + int (*complete)(DnsStream *s, int error); + + DnsTransaction *transaction; /* when used by the transaction logic */ + DnsQuery *query; /* when used by the DNS stub logic */ + + LIST_FIELDS(DnsStream, streams); +}; + +int dns_stream_new(Manager *m, DnsStream **s, DnsProtocol protocol, int fd); +DnsStream *dns_stream_unref(DnsStream *s); +DnsStream *dns_stream_ref(DnsStream *s); + +int dns_stream_write_packet(DnsStream *s, DnsPacket *p); + +static inline bool DNS_STREAM_QUEUED(DnsStream *s) { + assert(s); + + if (s->fd < 0) /* already stopped? */ + return false; + + return !!s->write_packet; +} diff --git a/src/grp-resolve/systemd-resolved/resolved-dns-stub.c b/src/grp-resolve/systemd-resolved/resolved-dns-stub.c new file mode 100644 index 0000000000..ad49862a70 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-dns-stub.c @@ -0,0 +1,539 @@ +/*** + This file is part of systemd. + + Copyright 2016 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include "systemd-basic/fd-util.h" +#include "systemd-basic/socket-util.h" + +#include "resolved-dns-stub.h" + +/* The MTU of the loopback device is 64K on Linux, advertise that as maximum datagram size, but subtract the Ethernet, + * IP and UDP header sizes */ +#define ADVERTISE_DATAGRAM_SIZE_MAX (65536U-14U-20U-8U) + +static int manager_dns_stub_udp_fd(Manager *m); +static int manager_dns_stub_tcp_fd(Manager *m); + +static int dns_stub_make_reply_packet( + uint16_t id, + int rcode, + DnsQuestion *q, + DnsAnswer *answer, + bool add_opt, /* add an OPT RR to this packet */ + bool edns0_do, /* set the EDNS0 DNSSEC OK bit */ + bool ad, /* set the DNSSEC authenticated data bit */ + DnsPacket **ret) { + + _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; + DnsResourceRecord *rr; + unsigned c = 0; + int r; + + /* Note that we don't bother with any additional RRs, as this is stub is for local lookups only, and hence + * roundtrips aren't expensive. */ + + r = dns_packet_new(&p, DNS_PROTOCOL_DNS, 0); + if (r < 0) + return r; + + /* If the client didn't do EDNS, clamp the rcode to 4 bit */ + if (!add_opt && rcode > 0xF) + rcode = DNS_RCODE_SERVFAIL; + + DNS_PACKET_HEADER(p)->id = id; + DNS_PACKET_HEADER(p)->flags = htobe16(DNS_PACKET_MAKE_FLAGS( + 1 /* qr */, + 0 /* opcode */, + 0 /* aa */, + 0 /* tc */, + 1 /* rd */, + 1 /* ra */, + ad /* ad */, + 0 /* cd */, + rcode)); + + r = dns_packet_append_question(p, q); + if (r < 0) + return r; + DNS_PACKET_HEADER(p)->qdcount = htobe16(dns_question_size(q)); + + DNS_ANSWER_FOREACH(rr, answer) { + r = dns_question_matches_rr(q, rr, NULL); + if (r < 0) + return r; + if (r > 0) + goto add; + + r = dns_question_matches_cname_or_dname(q, rr, NULL); + if (r < 0) + return r; + if (r > 0) + goto add; + + continue; + add: + r = dns_packet_append_rr(p, rr, NULL, NULL); + if (r < 0) + return r; + + c++; + } + DNS_PACKET_HEADER(p)->ancount = htobe16(c); + + if (add_opt) { + r = dns_packet_append_opt(p, ADVERTISE_DATAGRAM_SIZE_MAX, edns0_do, rcode, NULL); + if (r < 0) + return r; + } + + *ret = p; + p = NULL; + + return 0; +} + +static void dns_stub_detach_stream(DnsStream *s) { + assert(s); + + s->complete = NULL; + s->on_packet = NULL; + s->query = NULL; +} + +static int dns_stub_send(Manager *m, DnsStream *s, DnsPacket *p, DnsPacket *reply) { + int r; + + assert(m); + assert(p); + assert(reply); + + if (s) + r = dns_stream_write_packet(s, reply); + else { + int fd; + + /* Truncate the message to the right size */ + if (reply->size > DNS_PACKET_PAYLOAD_SIZE_MAX(p)) { + dns_packet_truncate(reply, DNS_PACKET_UNICAST_SIZE_MAX); + DNS_PACKET_HEADER(reply)->flags = htobe16(be16toh(DNS_PACKET_HEADER(reply)->flags) | DNS_PACKET_FLAG_TC); + } + + fd = manager_dns_stub_udp_fd(m); + if (fd < 0) + return log_debug_errno(fd, "Failed to get reply socket: %m"); + + /* Note that it is essential here that we explicitly choose the source IP address for this packet. This + * is because otherwise the kernel will choose it automatically based on the routing table and will + * thus pick 127.0.0.1 rather than 127.0.0.53. */ + + r = manager_send(m, fd, LOOPBACK_IFINDEX, p->family, &p->sender, p->sender_port, &p->destination, reply); + } + if (r < 0) + return log_debug_errno(r, "Failed to send reply packet: %m"); + + return 0; +} + +static int dns_stub_send_failure(Manager *m, DnsStream *s, DnsPacket *p, int rcode) { + _cleanup_(dns_packet_unrefp) DnsPacket *reply = NULL; + int r; + + assert(m); + assert(p); + + r = dns_stub_make_reply_packet(DNS_PACKET_ID(p), rcode, p->question, NULL, !!p->opt, DNS_PACKET_DO(p), false, &reply); + if (r < 0) + return log_debug_errno(r, "Failed to build failure packet: %m"); + + return dns_stub_send(m, s, p, reply); +} + +static void dns_stub_query_complete(DnsQuery *q) { + int r; + + assert(q); + assert(q->request_dns_packet); + + switch (q->state) { + + case DNS_TRANSACTION_SUCCESS: { + _cleanup_(dns_packet_unrefp) DnsPacket *reply = NULL; + + r = dns_stub_make_reply_packet( + DNS_PACKET_ID(q->request_dns_packet), + q->answer_rcode, + q->question_idna, + q->answer, + !!q->request_dns_packet->opt, + DNS_PACKET_DO(q->request_dns_packet), + DNS_PACKET_DO(q->request_dns_packet) && q->answer_authenticated, + &reply); + if (r < 0) { + log_debug_errno(r, "Failed to build reply packet: %m"); + break; + } + + (void) dns_stub_send(q->manager, q->request_dns_stream, q->request_dns_packet, reply); + break; + } + + case DNS_TRANSACTION_RCODE_FAILURE: + (void) dns_stub_send_failure(q->manager, q->request_dns_stream, q->request_dns_packet, q->answer_rcode); + break; + + case DNS_TRANSACTION_NOT_FOUND: + (void) dns_stub_send_failure(q->manager, q->request_dns_stream, q->request_dns_packet, DNS_RCODE_NXDOMAIN); + break; + + case DNS_TRANSACTION_TIMEOUT: + case DNS_TRANSACTION_ATTEMPTS_MAX_REACHED: + /* Propagate a timeout as a no packet, i.e. that the client also gets a timeout */ + break; + + case DNS_TRANSACTION_NO_SERVERS: + case DNS_TRANSACTION_INVALID_REPLY: + case DNS_TRANSACTION_ERRNO: + case DNS_TRANSACTION_ABORTED: + case DNS_TRANSACTION_DNSSEC_FAILED: + case DNS_TRANSACTION_NO_TRUST_ANCHOR: + case DNS_TRANSACTION_RR_TYPE_UNSUPPORTED: + case DNS_TRANSACTION_NETWORK_DOWN: + (void) dns_stub_send_failure(q->manager, q->request_dns_stream, q->request_dns_packet, DNS_RCODE_SERVFAIL); + break; + + case DNS_TRANSACTION_NULL: + case DNS_TRANSACTION_PENDING: + case DNS_TRANSACTION_VALIDATING: + default: + assert_not_reached("Impossible state"); + } + + /* If there's a packet to write set, let's leave the stream around */ + if (q->request_dns_stream && DNS_STREAM_QUEUED(q->request_dns_stream)) { + + /* Detach the stream from our query (make it an orphan), but do not drop the reference to it. The + * default completion action of the stream will drop the reference. */ + + dns_stub_detach_stream(q->request_dns_stream); + q->request_dns_stream = NULL; + } + + dns_query_free(q); +} + +static int dns_stub_stream_complete(DnsStream *s, int error) { + assert(s); + + log_debug_errno(error, "DNS TCP connection terminated, destroying query: %m"); + + assert(s->query); + dns_query_free(s->query); + + return 0; +} + +static void dns_stub_process_query(Manager *m, DnsStream *s, DnsPacket *p) { + DnsQuery *q = NULL; + int r; + + assert(m); + assert(p); + assert(p->protocol == DNS_PROTOCOL_DNS); + + /* Takes ownership of the *s stream object */ + + if (in_addr_is_localhost(p->family, &p->sender) <= 0 || + in_addr_is_localhost(p->family, &p->destination) <= 0) { + log_error("Got packet on unexpected IP range, refusing."); + dns_stub_send_failure(m, s, p, DNS_RCODE_SERVFAIL); + goto fail; + } + + r = dns_packet_extract(p); + if (r < 0) { + log_debug_errno(r, "Failed to extract resources from incoming packet, ignoring packet: %m"); + dns_stub_send_failure(m, s, p, DNS_RCODE_FORMERR); + goto fail; + } + + if (!DNS_PACKET_VERSION_SUPPORTED(p)) { + log_debug("Got EDNS OPT field with unsupported version number."); + dns_stub_send_failure(m, s, p, DNS_RCODE_BADVERS); + goto fail; + } + + if (dns_type_is_obsolete(p->question->keys[0]->type)) { + log_debug("Got message with obsolete key type, refusing."); + dns_stub_send_failure(m, s, p, DNS_RCODE_NOTIMP); + goto fail; + } + + if (dns_type_is_zone_transer(p->question->keys[0]->type)) { + log_debug("Got request for zone transfer, refusing."); + dns_stub_send_failure(m, s, p, DNS_RCODE_NOTIMP); + goto fail; + } + + if (!DNS_PACKET_RD(p)) { + /* If the "rd" bit is off (i.e. recursion was not requested), then refuse operation */ + log_debug("Got request with recursion disabled, refusing."); + dns_stub_send_failure(m, s, p, DNS_RCODE_REFUSED); + goto fail; + } + + if (DNS_PACKET_DO(p) && DNS_PACKET_CD(p)) { + log_debug("Got request with DNSSEC CD bit set, refusing."); + dns_stub_send_failure(m, s, p, DNS_RCODE_NOTIMP); + goto fail; + } + + r = dns_query_new(m, &q, p->question, p->question, 0, SD_RESOLVED_PROTOCOLS_ALL|SD_RESOLVED_NO_SEARCH|SD_RESOLVED_NO_CNAME); + if (r < 0) { + log_error_errno(r, "Failed to generate query object: %m"); + dns_stub_send_failure(m, s, p, DNS_RCODE_SERVFAIL); + goto fail; + } + + /* Request that the TTL is corrected by the cached time for this lookup, so that we return vaguely useful TTLs */ + q->clamp_ttl = true; + + q->request_dns_packet = dns_packet_ref(p); + q->request_dns_stream = dns_stream_ref(s); /* make sure the stream stays around until we can send a reply through it */ + q->complete = dns_stub_query_complete; + + if (s) { + s->on_packet = NULL; + s->complete = dns_stub_stream_complete; + s->query = q; + } + + r = dns_query_go(q); + if (r < 0) { + log_error_errno(r, "Failed to start query: %m"); + dns_stub_send_failure(m, s, p, DNS_RCODE_SERVFAIL); + goto fail; + } + + log_info("Processing query..."); + return; + +fail: + if (s && DNS_STREAM_QUEUED(s)) + dns_stub_detach_stream(s); + + dns_query_free(q); +} + +static int on_dns_stub_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) { + _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; + Manager *m = userdata; + int r; + + r = manager_recv(m, fd, DNS_PROTOCOL_DNS, &p); + if (r <= 0) + return r; + + if (dns_packet_validate_query(p) > 0) { + log_debug("Got DNS stub UDP query packet for id %u", DNS_PACKET_ID(p)); + + dns_stub_process_query(m, NULL, p); + } else + log_debug("Invalid DNS stub UDP packet, ignoring."); + + return 0; +} + +static int manager_dns_stub_udp_fd(Manager *m) { + static const int one = 1; + union sockaddr_union sa = { + .in.sin_family = AF_INET, + .in.sin_port = htobe16(53), + .in.sin_addr.s_addr = htobe32(INADDR_DNS_STUB), + }; + _cleanup_close_ int fd = -1; + int r; + + if (m->dns_stub_udp_fd >= 0) + return m->dns_stub_udp_fd; + + fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); + if (fd < 0) + return -errno; + + if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof one) < 0) + return -errno; + + if (setsockopt(fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof one) < 0) + return -errno; + + if (setsockopt(fd, IPPROTO_IP, IP_RECVTTL, &one, sizeof one) < 0) + return -errno; + + /* Make sure no traffic from outside the local host can leak to onto this socket */ + if (setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, "lo", 3) < 0) + return -errno; + + if (bind(fd, &sa.sa, sizeof(sa.in)) < 0) + return -errno; + + r = sd_event_add_io(m->event, &m->dns_stub_udp_event_source, fd, EPOLLIN, on_dns_stub_packet, m); + if (r < 0) + return r; + + (void) sd_event_source_set_description(m->dns_stub_udp_event_source, "dns-stub-udp"); + m->dns_stub_udp_fd = fd; + fd = -1; + + return m->dns_stub_udp_fd; +} + +static int on_dns_stub_stream_packet(DnsStream *s) { + assert(s); + assert(s->read_packet); + + if (dns_packet_validate_query(s->read_packet) > 0) { + log_debug("Got DNS stub TCP query packet for id %u", DNS_PACKET_ID(s->read_packet)); + + dns_stub_process_query(s->manager, s, s->read_packet); + } else + log_debug("Invalid DNS stub TCP packet, ignoring."); + + /* Drop the reference to the stream. Either a query was created and added its own reference to the stream now, + * or that didn't happen in which case we want to free the stream */ + dns_stream_unref(s); + + return 0; +} + +static int on_dns_stub_stream(sd_event_source *s, int fd, uint32_t revents, void *userdata) { + DnsStream *stream; + Manager *m = userdata; + int cfd, r; + + cfd = accept4(fd, NULL, NULL, SOCK_NONBLOCK|SOCK_CLOEXEC); + if (cfd < 0) { + if (errno == EAGAIN || errno == EINTR) + return 0; + + return -errno; + } + + r = dns_stream_new(m, &stream, DNS_PROTOCOL_DNS, cfd); + if (r < 0) { + safe_close(cfd); + return r; + } + + stream->on_packet = on_dns_stub_stream_packet; + + /* We let the reference to the stream dangling here, it will either be dropped by the default "complete" action + * of the stream, or by our packet callback, or when the manager is shut down. */ + + return 0; +} + +static int manager_dns_stub_tcp_fd(Manager *m) { + static const int one = 1; + union sockaddr_union sa = { + .in.sin_family = AF_INET, + .in.sin_addr.s_addr = htobe32(INADDR_DNS_STUB), + .in.sin_port = htobe16(53), + }; + _cleanup_close_ int fd = -1; + int r; + + if (m->dns_stub_tcp_fd >= 0) + return m->dns_stub_tcp_fd; + + fd = socket(AF_INET, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); + if (fd < 0) + return -errno; + + if (setsockopt(fd, IPPROTO_IP, IP_TTL, &one, sizeof one) < 0) + return -errno; + + if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof one) < 0) + return -errno; + + if (setsockopt(fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof one) < 0) + return -errno; + + if (setsockopt(fd, IPPROTO_IP, IP_RECVTTL, &one, sizeof one) < 0) + return -errno; + + /* Make sure no traffic from outside the local host can leak to onto this socket */ + if (setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, "lo", 3) < 0) + return -errno; + + if (bind(fd, &sa.sa, sizeof(sa.in)) < 0) + return -errno; + + if (listen(fd, SOMAXCONN) < 0) + return -errno; + + r = sd_event_add_io(m->event, &m->dns_stub_tcp_event_source, fd, EPOLLIN, on_dns_stub_stream, m); + if (r < 0) + return r; + + (void) sd_event_source_set_description(m->dns_stub_tcp_event_source, "dns-stub-tcp"); + m->dns_stub_tcp_fd = fd; + fd = -1; + + return m->dns_stub_tcp_fd; +} + +int manager_dns_stub_start(Manager *m) { + const char *t = "UDP"; + int r = 0; + + assert(m); + + if (IN_SET(m->dns_stub_listener_mode, DNS_STUB_LISTENER_YES, DNS_STUB_LISTENER_UDP)) + r = manager_dns_stub_udp_fd(m); + + if (r >= 0 && + IN_SET(m->dns_stub_listener_mode, DNS_STUB_LISTENER_YES, DNS_STUB_LISTENER_TCP)) { + t = "TCP"; + r = manager_dns_stub_tcp_fd(m); + } + + if (IN_SET(r, -EADDRINUSE, -EPERM)) { + if (r == -EADDRINUSE) + log_warning_errno(r, + "Another process is already listening on %s socket 127.0.0.53:53.\n" + "Turning off local DNS stub support.", t); + else + log_warning_errno(r, + "Failed to listen on %s socket 127.0.0.53:53: %m.\n" + "Turning off local DNS stub support.", t); + manager_dns_stub_stop(m); + } else if (r < 0) + return log_error_errno(r, "Failed to listen on %s socket 127.0.0.53:53: %m", t); + + return 0; +} + +void manager_dns_stub_stop(Manager *m) { + assert(m); + + m->dns_stub_udp_event_source = sd_event_source_unref(m->dns_stub_udp_event_source); + m->dns_stub_tcp_event_source = sd_event_source_unref(m->dns_stub_tcp_event_source); + + m->dns_stub_udp_fd = safe_close(m->dns_stub_udp_fd); + m->dns_stub_tcp_fd = safe_close(m->dns_stub_tcp_fd); +} diff --git a/src/grp-resolve/systemd-resolved/resolved-dns-stub.h b/src/grp-resolve/systemd-resolved/resolved-dns-stub.h new file mode 100644 index 0000000000..12b86f6753 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-dns-stub.h @@ -0,0 +1,28 @@ +#pragma once + +/*** + This file is part of systemd. + + Copyright 2016 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include "resolved-manager.h" + +/* 127.0.0.53 in native endian */ +#define INADDR_DNS_STUB ((in_addr_t) 0x7f000035U) + +void manager_dns_stub_stop(Manager *m); +int manager_dns_stub_start(Manager *m); diff --git a/src/grp-resolve/systemd-resolved/resolved-dns-synthesize.c b/src/grp-resolve/systemd-resolved/resolved-dns-synthesize.c new file mode 100644 index 0000000000..53d1940d9e --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-dns-synthesize.c @@ -0,0 +1,414 @@ +/*** + This file is part of systemd. + + Copyright 2014 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include "sd-netlink/local-addresses.h" +#include "systemd-basic/alloc-util.h" +#include "systemd-basic/hostname-util.h" + +#include "resolved-dns-synthesize.h" + +int dns_synthesize_ifindex(int ifindex) { + + /* When the caller asked for resolving on a specific + * interface, we synthesize the answer for that + * interface. However, if nothing specific was claimed and we + * only return localhost RRs, we synthesize the answer for + * localhost. */ + + if (ifindex > 0) + return ifindex; + + return LOOPBACK_IFINDEX; +} + +int dns_synthesize_family(uint64_t flags) { + + /* Picks an address family depending on set flags. This is + * purely for synthesized answers, where the family we return + * for the reply should match what was requested in the + * question, even though we are synthesizing the answer + * here. */ + + if (!(flags & SD_RESOLVED_DNS)) { + if (flags & (SD_RESOLVED_LLMNR_IPV4|SD_RESOLVED_MDNS_IPV4)) + return AF_INET; + if (flags & (SD_RESOLVED_LLMNR_IPV6|SD_RESOLVED_MDNS_IPV6)) + return AF_INET6; + } + + return AF_UNSPEC; +} + +DnsProtocol dns_synthesize_protocol(uint64_t flags) { + + /* Similar as dns_synthesize_family() but does this for the + * protocol. If resolving via DNS was requested, we claim it + * was DNS. Similar, if nothing specific was + * requested. However, if only resolving via LLMNR was + * requested we return that. */ + + if (flags & SD_RESOLVED_DNS) + return DNS_PROTOCOL_DNS; + if (flags & SD_RESOLVED_LLMNR) + return DNS_PROTOCOL_LLMNR; + if (flags & SD_RESOLVED_MDNS) + return DNS_PROTOCOL_MDNS; + + return DNS_PROTOCOL_DNS; +} + +static int synthesize_localhost_rr(Manager *m, const DnsResourceKey *key, int ifindex, DnsAnswer **answer) { + int r; + + assert(m); + assert(key); + assert(answer); + + r = dns_answer_reserve(answer, 2); + if (r < 0) + return r; + + if (IN_SET(key->type, DNS_TYPE_A, DNS_TYPE_ANY)) { + _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL; + + rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_A, dns_resource_key_name(key)); + if (!rr) + return -ENOMEM; + + rr->a.in_addr.s_addr = htobe32(INADDR_LOOPBACK); + + r = dns_answer_add(*answer, rr, dns_synthesize_ifindex(ifindex), DNS_ANSWER_AUTHENTICATED); + if (r < 0) + return r; + } + + if (IN_SET(key->type, DNS_TYPE_AAAA, DNS_TYPE_ANY)) { + _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL; + + rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_AAAA, dns_resource_key_name(key)); + if (!rr) + return -ENOMEM; + + rr->aaaa.in6_addr = in6addr_loopback; + + r = dns_answer_add(*answer, rr, dns_synthesize_ifindex(ifindex), DNS_ANSWER_AUTHENTICATED); + if (r < 0) + return r; + } + + return 0; +} + +static int answer_add_ptr(DnsAnswer **answer, const char *from, const char *to, int ifindex, DnsAnswerFlags flags) { + _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL; + + rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_PTR, from); + if (!rr) + return -ENOMEM; + + rr->ptr.name = strdup(to); + if (!rr->ptr.name) + return -ENOMEM; + + return dns_answer_add(*answer, rr, ifindex, flags); +} + +static int synthesize_localhost_ptr(Manager *m, const DnsResourceKey *key, int ifindex, DnsAnswer **answer) { + int r; + + assert(m); + assert(key); + assert(answer); + + if (IN_SET(key->type, DNS_TYPE_PTR, DNS_TYPE_ANY)) { + r = dns_answer_reserve(answer, 1); + if (r < 0) + return r; + + r = answer_add_ptr(answer, dns_resource_key_name(key), "localhost", dns_synthesize_ifindex(ifindex), DNS_ANSWER_AUTHENTICATED); + if (r < 0) + return r; + } + + return 0; +} + +static int answer_add_addresses_rr( + DnsAnswer **answer, + const char *name, + struct local_address *addresses, + unsigned n_addresses) { + + unsigned j; + int r; + + assert(answer); + assert(name); + + r = dns_answer_reserve(answer, n_addresses); + if (r < 0) + return r; + + for (j = 0; j < n_addresses; j++) { + _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL; + + r = dns_resource_record_new_address(&rr, addresses[j].family, &addresses[j].address, name); + if (r < 0) + return r; + + r = dns_answer_add(*answer, rr, addresses[j].ifindex, DNS_ANSWER_AUTHENTICATED); + if (r < 0) + return r; + } + + return 0; +} + +static int answer_add_addresses_ptr( + DnsAnswer **answer, + const char *name, + struct local_address *addresses, + unsigned n_addresses, + int af, const union in_addr_union *match) { + + unsigned j; + int r; + + assert(answer); + assert(name); + + for (j = 0; j < n_addresses; j++) { + _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL; + + if (af != AF_UNSPEC) { + + if (addresses[j].family != af) + continue; + + if (match && !in_addr_equal(af, match, &addresses[j].address)) + continue; + } + + r = dns_answer_reserve(answer, 1); + if (r < 0) + return r; + + r = dns_resource_record_new_reverse(&rr, addresses[j].family, &addresses[j].address, name); + if (r < 0) + return r; + + r = dns_answer_add(*answer, rr, addresses[j].ifindex, DNS_ANSWER_AUTHENTICATED); + if (r < 0) + return r; + } + + return 0; +} + +static int synthesize_system_hostname_rr(Manager *m, const DnsResourceKey *key, int ifindex, DnsAnswer **answer) { + _cleanup_free_ struct local_address *addresses = NULL; + int n = 0, af; + + assert(m); + assert(key); + assert(answer); + + af = dns_type_to_af(key->type); + if (af >= 0) { + n = local_addresses(m->rtnl, ifindex, af, &addresses); + if (n < 0) + return n; + + if (n == 0) { + struct local_address buffer[2]; + + /* If we have no local addresses then use ::1 + * and 127.0.0.2 as local ones. */ + + if (af == AF_INET || af == AF_UNSPEC) + buffer[n++] = (struct local_address) { + .family = AF_INET, + .ifindex = dns_synthesize_ifindex(ifindex), + .address.in.s_addr = htobe32(0x7F000002), + }; + + if (af == AF_INET6 || af == AF_UNSPEC) + buffer[n++] = (struct local_address) { + .family = AF_INET6, + .ifindex = dns_synthesize_ifindex(ifindex), + .address.in6 = in6addr_loopback, + }; + + return answer_add_addresses_rr(answer, dns_resource_key_name(key), buffer, n); + } + } + + return answer_add_addresses_rr(answer, dns_resource_key_name(key), addresses, n); +} + +static int synthesize_system_hostname_ptr(Manager *m, int af, const union in_addr_union *address, int ifindex, DnsAnswer **answer) { + _cleanup_free_ struct local_address *addresses = NULL; + int n, r; + + assert(m); + assert(address); + assert(answer); + + if (af == AF_INET && address->in.s_addr == htobe32(0x7F000002)) { + + /* Always map the IPv4 address 127.0.0.2 to the local + * hostname, in addition to "localhost": */ + + r = dns_answer_reserve(answer, 3); + if (r < 0) + return r; + + r = answer_add_ptr(answer, "2.0.0.127.in-addr.arpa", m->llmnr_hostname, dns_synthesize_ifindex(ifindex), DNS_ANSWER_AUTHENTICATED); + if (r < 0) + return r; + + r = answer_add_ptr(answer, "2.0.0.127.in-addr.arpa", m->mdns_hostname, dns_synthesize_ifindex(ifindex), DNS_ANSWER_AUTHENTICATED); + if (r < 0) + return r; + + r = answer_add_ptr(answer, "2.0.0.127.in-addr.arpa", "localhost", dns_synthesize_ifindex(ifindex), DNS_ANSWER_AUTHENTICATED); + if (r < 0) + return r; + + return 0; + } + + n = local_addresses(m->rtnl, ifindex, af, &addresses); + if (n < 0) + return n; + + r = answer_add_addresses_ptr(answer, m->llmnr_hostname, addresses, n, af, address); + if (r < 0) + return r; + + return answer_add_addresses_ptr(answer, m->mdns_hostname, addresses, n, af, address); +} + +static int synthesize_gateway_rr(Manager *m, const DnsResourceKey *key, int ifindex, DnsAnswer **answer) { + _cleanup_free_ struct local_address *addresses = NULL; + int n = 0, af; + + assert(m); + assert(key); + assert(answer); + + af = dns_type_to_af(key->type); + if (af >= 0) { + n = local_gateways(m->rtnl, ifindex, af, &addresses); + if (n < 0) + return n; + } + + return answer_add_addresses_rr(answer, dns_resource_key_name(key), addresses, n); +} + +static int synthesize_gateway_ptr(Manager *m, int af, const union in_addr_union *address, int ifindex, DnsAnswer **answer) { + _cleanup_free_ struct local_address *addresses = NULL; + int n; + + assert(m); + assert(address); + assert(answer); + + n = local_gateways(m->rtnl, ifindex, af, &addresses); + if (n < 0) + return n; + + return answer_add_addresses_ptr(answer, "gateway", addresses, n, af, address); +} + +int dns_synthesize_answer( + Manager *m, + DnsQuestion *q, + int ifindex, + DnsAnswer **ret) { + + _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL; + DnsResourceKey *key; + bool found = false; + int r; + + assert(m); + assert(q); + + DNS_QUESTION_FOREACH(key, q) { + union in_addr_union address; + const char *name; + int af; + + if (key->class != DNS_CLASS_IN && + key->class != DNS_CLASS_ANY) + continue; + + name = dns_resource_key_name(key); + + if (is_localhost(name)) { + + r = synthesize_localhost_rr(m, key, ifindex, &answer); + if (r < 0) + return log_error_errno(r, "Failed to synthesize localhost RRs: %m"); + + } else if (manager_is_own_hostname(m, name)) { + + r = synthesize_system_hostname_rr(m, key, ifindex, &answer); + if (r < 0) + return log_error_errno(r, "Failed to synthesize system hostname RRs: %m"); + + } else if (is_gateway_hostname(name)) { + + r = synthesize_gateway_rr(m, key, ifindex, &answer); + if (r < 0) + return log_error_errno(r, "Failed to synthesize gateway RRs: %m"); + + } else if ((dns_name_endswith(name, "127.in-addr.arpa") > 0 && dns_name_equal(name, "2.0.0.127.in-addr.arpa") == 0) || + dns_name_equal(name, "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa") > 0) { + + r = synthesize_localhost_ptr(m, key, ifindex, &answer); + if (r < 0) + return log_error_errno(r, "Failed to synthesize localhost PTR RRs: %m"); + + } else if (dns_name_address(name, &af, &address) > 0) { + + r = synthesize_system_hostname_ptr(m, af, &address, ifindex, &answer); + if (r < 0) + return log_error_errno(r, "Failed to synthesize system hostname PTR RR: %m"); + + r = synthesize_gateway_ptr(m, af, &address, ifindex, &answer); + if (r < 0) + return log_error_errno(r, "Failed to synthesize gateway hostname PTR RR: %m"); + } else + continue; + + found = true; + } + + r = found; + + if (ret) { + *ret = answer; + answer = NULL; + } + + return r; +} diff --git a/src/grp-resolve/systemd-resolved/resolved-dns-synthesize.h b/src/grp-resolve/systemd-resolved/resolved-dns-synthesize.h new file mode 100644 index 0000000000..23b05587ac --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-dns-synthesize.h @@ -0,0 +1,31 @@ +#pragma once + +/*** + This file is part of systemd. + + Copyright 2016 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include "basic-dns/resolved-dns-answer.h" +#include "basic-dns/resolved-dns-question.h" + +#include "resolved-manager.h" + +int dns_synthesize_ifindex(int ifindex); +int dns_synthesize_family(uint64_t flags); +DnsProtocol dns_synthesize_protocol(uint64_t flags); + +int dns_synthesize_answer(Manager *m, DnsQuestion *q, int ifindex, DnsAnswer **ret); diff --git a/src/grp-resolve/systemd-resolved/resolved-dns-transaction.c b/src/grp-resolve/systemd-resolved/resolved-dns-transaction.c new file mode 100644 index 0000000000..b17493d659 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-dns-transaction.c @@ -0,0 +1,3107 @@ +/*** + This file is part of systemd. + + Copyright 2014 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include <systemd/sd-messages.h> + +#include "systemd-basic/af-list.h" +#include "systemd-basic/alloc-util.h" +#include "systemd-basic/errno-list.h" +#include "systemd-basic/fd-util.h" +#include "systemd-basic/random-util.h" +#include "systemd-basic/string-table.h" +#include "systemd-shared/dns-domain.h" + +#include "resolved-dns-cache.h" +#include "resolved-dns-transaction.h" +#include "resolved-llmnr.h" + +#define TRANSACTIONS_MAX 4096 + +static void dns_transaction_reset_answer(DnsTransaction *t) { + assert(t); + + t->received = dns_packet_unref(t->received); + t->answer = dns_answer_unref(t->answer); + t->answer_rcode = 0; + t->answer_dnssec_result = _DNSSEC_RESULT_INVALID; + t->answer_source = _DNS_TRANSACTION_SOURCE_INVALID; + t->answer_authenticated = false; + t->answer_nsec_ttl = (uint32_t) -1; + t->answer_errno = 0; +} + +static void dns_transaction_flush_dnssec_transactions(DnsTransaction *t) { + DnsTransaction *z; + + assert(t); + + while ((z = set_steal_first(t->dnssec_transactions))) { + set_remove(z->notify_transactions, t); + set_remove(z->notify_transactions_done, t); + dns_transaction_gc(z); + } +} + +static void dns_transaction_close_connection(DnsTransaction *t) { + assert(t); + + if (t->stream) { + /* Let's detach the stream from our transaction, in case something else keeps a reference to it. */ + t->stream->complete = NULL; + t->stream->on_packet = NULL; + t->stream->transaction = NULL; + t->stream = dns_stream_unref(t->stream); + } + + t->dns_udp_event_source = sd_event_source_unref(t->dns_udp_event_source); + t->dns_udp_fd = safe_close(t->dns_udp_fd); +} + +static void dns_transaction_stop_timeout(DnsTransaction *t) { + assert(t); + + t->timeout_event_source = sd_event_source_unref(t->timeout_event_source); +} + +DnsTransaction* dns_transaction_free(DnsTransaction *t) { + DnsQueryCandidate *c; + DnsZoneItem *i; + DnsTransaction *z; + + if (!t) + return NULL; + + log_debug("Freeing transaction %" PRIu16 ".", t->id); + + dns_transaction_close_connection(t); + dns_transaction_stop_timeout(t); + + dns_packet_unref(t->sent); + dns_transaction_reset_answer(t); + + dns_server_unref(t->server); + + if (t->scope) { + hashmap_remove_value(t->scope->transactions_by_key, t->key, t); + LIST_REMOVE(transactions_by_scope, t->scope->transactions, t); + + if (t->id != 0) + hashmap_remove(t->scope->manager->dns_transactions, UINT_TO_PTR(t->id)); + } + + while ((c = set_steal_first(t->notify_query_candidates))) + set_remove(c->transactions, t); + set_free(t->notify_query_candidates); + + while ((c = set_steal_first(t->notify_query_candidates_done))) + set_remove(c->transactions, t); + set_free(t->notify_query_candidates_done); + + while ((i = set_steal_first(t->notify_zone_items))) + i->probe_transaction = NULL; + set_free(t->notify_zone_items); + + while ((i = set_steal_first(t->notify_zone_items_done))) + i->probe_transaction = NULL; + set_free(t->notify_zone_items_done); + + while ((z = set_steal_first(t->notify_transactions))) + set_remove(z->dnssec_transactions, t); + set_free(t->notify_transactions); + + while ((z = set_steal_first(t->notify_transactions_done))) + set_remove(z->dnssec_transactions, t); + set_free(t->notify_transactions_done); + + dns_transaction_flush_dnssec_transactions(t); + set_free(t->dnssec_transactions); + + dns_answer_unref(t->validated_keys); + dns_resource_key_unref(t->key); + + return mfree(t); +} + +DEFINE_TRIVIAL_CLEANUP_FUNC(DnsTransaction*, dns_transaction_free); + +bool dns_transaction_gc(DnsTransaction *t) { + assert(t); + + if (t->block_gc > 0) + return true; + + if (set_isempty(t->notify_query_candidates) && + set_isempty(t->notify_query_candidates_done) && + set_isempty(t->notify_zone_items) && + set_isempty(t->notify_zone_items_done) && + set_isempty(t->notify_transactions) && + set_isempty(t->notify_transactions_done)) { + dns_transaction_free(t); + return false; + } + + return true; +} + +static uint16_t pick_new_id(Manager *m) { + uint16_t new_id; + + /* Find a fresh, unused transaction id. Note that this loop is bounded because there's a limit on the number of + * transactions, and it's much lower than the space of IDs. */ + + assert_cc(TRANSACTIONS_MAX < 0xFFFF); + + do + random_bytes(&new_id, sizeof(new_id)); + while (new_id == 0 || + hashmap_get(m->dns_transactions, UINT_TO_PTR(new_id))); + + return new_id; +} + +int dns_transaction_new(DnsTransaction **ret, DnsScope *s, DnsResourceKey *key) { + _cleanup_(dns_transaction_freep) DnsTransaction *t = NULL; + int r; + + assert(ret); + assert(s); + assert(key); + + /* Don't allow looking up invalid or pseudo RRs */ + if (!dns_type_is_valid_query(key->type)) + return -EINVAL; + if (dns_type_is_obsolete(key->type)) + return -EOPNOTSUPP; + + /* We only support the IN class */ + if (key->class != DNS_CLASS_IN && key->class != DNS_CLASS_ANY) + return -EOPNOTSUPP; + + if (hashmap_size(s->manager->dns_transactions) >= TRANSACTIONS_MAX) + return -EBUSY; + + r = hashmap_ensure_allocated(&s->manager->dns_transactions, NULL); + if (r < 0) + return r; + + r = hashmap_ensure_allocated(&s->transactions_by_key, &dns_resource_key_hash_ops); + if (r < 0) + return r; + + t = new0(DnsTransaction, 1); + if (!t) + return -ENOMEM; + + t->dns_udp_fd = -1; + t->answer_source = _DNS_TRANSACTION_SOURCE_INVALID; + t->answer_dnssec_result = _DNSSEC_RESULT_INVALID; + t->answer_nsec_ttl = (uint32_t) -1; + t->key = dns_resource_key_ref(key); + t->current_feature_level = _DNS_SERVER_FEATURE_LEVEL_INVALID; + t->clamp_feature_level = _DNS_SERVER_FEATURE_LEVEL_INVALID; + + t->id = pick_new_id(s->manager); + + r = hashmap_put(s->manager->dns_transactions, UINT_TO_PTR(t->id), t); + if (r < 0) { + t->id = 0; + return r; + } + + r = hashmap_replace(s->transactions_by_key, t->key, t); + if (r < 0) { + hashmap_remove(s->manager->dns_transactions, UINT_TO_PTR(t->id)); + return r; + } + + LIST_PREPEND(transactions_by_scope, s->transactions, t); + t->scope = s; + + s->manager->n_transactions_total++; + + if (ret) + *ret = t; + + t = NULL; + + return 0; +} + +static void dns_transaction_shuffle_id(DnsTransaction *t) { + uint16_t new_id; + assert(t); + + /* Pick a new ID for this transaction. */ + + new_id = pick_new_id(t->scope->manager); + assert_se(hashmap_remove_and_put(t->scope->manager->dns_transactions, UINT_TO_PTR(t->id), UINT_TO_PTR(new_id), t) >= 0); + + log_debug("Transaction %" PRIu16 " is now %" PRIu16 ".", t->id, new_id); + t->id = new_id; + + /* Make sure we generate a new packet with the new ID */ + t->sent = dns_packet_unref(t->sent); +} + +static void dns_transaction_tentative(DnsTransaction *t, DnsPacket *p) { + _cleanup_free_ char *pretty = NULL; + char key_str[DNS_RESOURCE_KEY_STRING_MAX]; + DnsZoneItem *z; + + assert(t); + assert(p); + + if (manager_our_packet(t->scope->manager, p) != 0) + return; + + (void) in_addr_to_string(p->family, &p->sender, &pretty); + + log_debug("Transaction %" PRIu16 " for <%s> on scope %s on %s/%s got tentative packet from %s.", + t->id, + dns_resource_key_to_string(t->key, key_str, sizeof key_str), + dns_protocol_to_string(t->scope->protocol), + t->scope->link ? t->scope->link->name : "*", + af_to_name_short(t->scope->family), + strnull(pretty)); + + /* RFC 4795, Section 4.1 says that the peer with the + * lexicographically smaller IP address loses */ + if (memcmp(&p->sender, &p->destination, FAMILY_ADDRESS_SIZE(p->family)) >= 0) { + log_debug("Peer has lexicographically larger IP address and thus lost in the conflict."); + return; + } + + log_debug("We have the lexicographically larger IP address and thus lost in the conflict."); + + t->block_gc++; + + while ((z = set_first(t->notify_zone_items))) { + /* First, make sure the zone item drops the reference + * to us */ + dns_zone_item_probe_stop(z); + + /* Secondly, report this as conflict, so that we might + * look for a different hostname */ + dns_zone_item_conflict(z); + } + t->block_gc--; + + dns_transaction_gc(t); +} + +void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state) { + DnsQueryCandidate *c; + DnsZoneItem *z; + DnsTransaction *d; + const char *st; + char key_str[DNS_RESOURCE_KEY_STRING_MAX]; + + assert(t); + assert(!DNS_TRANSACTION_IS_LIVE(state)); + + if (state == DNS_TRANSACTION_DNSSEC_FAILED) { + dns_resource_key_to_string(t->key, key_str, sizeof key_str); + + log_struct(LOG_NOTICE, + LOG_MESSAGE_ID(SD_MESSAGE_DNSSEC_FAILURE), + LOG_MESSAGE("DNSSEC validation failed for question %s: %s", key_str, dnssec_result_to_string(t->answer_dnssec_result)), + "DNS_TRANSACTION=%" PRIu16, t->id, + "DNS_QUESTION=%s", key_str, + "DNSSEC_RESULT=%s", dnssec_result_to_string(t->answer_dnssec_result), + "DNS_SERVER=%s", dns_server_string(t->server), + "DNS_SERVER_FEATURE_LEVEL=%s", dns_server_feature_level_to_string(t->server->possible_feature_level), + NULL); + } + + /* Note that this call might invalidate the query. Callers + * should hence not attempt to access the query or transaction + * after calling this function. */ + + if (state == DNS_TRANSACTION_ERRNO) + st = errno_to_name(t->answer_errno); + else + st = dns_transaction_state_to_string(state); + + log_debug("Transaction %" PRIu16 " for <%s> on scope %s on %s/%s now complete with <%s> from %s (%s).", + t->id, + dns_resource_key_to_string(t->key, key_str, sizeof key_str), + dns_protocol_to_string(t->scope->protocol), + t->scope->link ? t->scope->link->name : "*", + af_to_name_short(t->scope->family), + st, + t->answer_source < 0 ? "none" : dns_transaction_source_to_string(t->answer_source), + t->answer_authenticated ? "authenticated" : "unsigned"); + + t->state = state; + + dns_transaction_close_connection(t); + dns_transaction_stop_timeout(t); + + /* Notify all queries that are interested, but make sure the + * transaction isn't freed while we are still looking at it */ + t->block_gc++; + + SET_FOREACH_MOVE(c, t->notify_query_candidates_done, t->notify_query_candidates) + dns_query_candidate_notify(c); + SWAP_TWO(t->notify_query_candidates, t->notify_query_candidates_done); + + SET_FOREACH_MOVE(z, t->notify_zone_items_done, t->notify_zone_items) + dns_zone_item_notify(z); + SWAP_TWO(t->notify_zone_items, t->notify_zone_items_done); + + SET_FOREACH_MOVE(d, t->notify_transactions_done, t->notify_transactions) + dns_transaction_notify(d, t); + SWAP_TWO(t->notify_transactions, t->notify_transactions_done); + + t->block_gc--; + dns_transaction_gc(t); +} + +static int dns_transaction_pick_server(DnsTransaction *t) { + DnsServer *server; + + assert(t); + assert(t->scope->protocol == DNS_PROTOCOL_DNS); + + /* Pick a DNS server and a feature level for it. */ + + server = dns_scope_get_dns_server(t->scope); + if (!server) + return -ESRCH; + + /* If we changed the server invalidate the feature level clamping, as the new server might have completely + * different properties. */ + if (server != t->server) + t->clamp_feature_level = _DNS_SERVER_FEATURE_LEVEL_INVALID; + + t->current_feature_level = dns_server_possible_feature_level(server); + + /* Clamp the feature level if that is requested. */ + if (t->clamp_feature_level != _DNS_SERVER_FEATURE_LEVEL_INVALID && + t->current_feature_level > t->clamp_feature_level) + t->current_feature_level = t->clamp_feature_level; + + log_debug("Using feature level %s for transaction %u.", dns_server_feature_level_to_string(t->current_feature_level), t->id); + + if (server == t->server) + return 0; + + dns_server_unref(t->server); + t->server = dns_server_ref(server); + + log_debug("Using DNS server %s for transaction %u.", dns_server_string(t->server), t->id); + + return 1; +} + +static void dns_transaction_retry(DnsTransaction *t, bool next_server) { + int r; + + assert(t); + + log_debug("Retrying transaction %" PRIu16 ".", t->id); + + /* Before we try again, switch to a new server. */ + if (next_server) + dns_scope_next_dns_server(t->scope); + + r = dns_transaction_go(t); + if (r < 0) { + t->answer_errno = -r; + dns_transaction_complete(t, DNS_TRANSACTION_ERRNO); + } +} + +static int dns_transaction_maybe_restart(DnsTransaction *t) { + int r; + + assert(t); + + /* Returns > 0 if the transaction was restarted, 0 if not */ + + if (!t->server) + return 0; + + if (t->current_feature_level <= dns_server_possible_feature_level(t->server)) + return 0; + + /* The server's current feature level is lower than when we sent the original query. We learnt something from + the response or possibly an auxiliary DNSSEC response that we didn't know before. We take that as reason to + restart the whole transaction. This is a good idea to deal with servers that respond rubbish if we include + OPT RR or DO bit. One of these cases is documented here, for example: + https://open.nlnetlabs.nl/pipermail/dnssec-trigger/2014-November/000376.html */ + + log_debug("Server feature level is now lower than when we began our transaction. Restarting with new ID."); + dns_transaction_shuffle_id(t); + + r = dns_transaction_go(t); + if (r < 0) + return r; + + return 1; +} + +static int on_stream_complete(DnsStream *s, int error) { + _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; + DnsTransaction *t; + + assert(s); + assert(s->transaction); + + /* Copy the data we care about out of the stream before we + * destroy it. */ + t = s->transaction; + p = dns_packet_ref(s->read_packet); + + dns_transaction_close_connection(t); + + if (ERRNO_IS_DISCONNECT(error)) { + usec_t usec; + + if (t->scope->protocol == DNS_PROTOCOL_LLMNR) { + /* If the LLMNR/TCP connection failed, the host doesn't support LLMNR, and we cannot answer the + * question on this scope. */ + dns_transaction_complete(t, DNS_TRANSACTION_NOT_FOUND); + return 0; + } + + log_debug_errno(error, "Connection failure for DNS TCP stream: %m"); + assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &usec) >= 0); + dns_server_packet_lost(t->server, IPPROTO_TCP, t->current_feature_level, usec - t->start_usec); + + dns_transaction_retry(t, true); + return 0; + } + if (error != 0) { + t->answer_errno = error; + dns_transaction_complete(t, DNS_TRANSACTION_ERRNO); + return 0; + } + + if (dns_packet_validate_reply(p) <= 0) { + log_debug("Invalid TCP reply packet."); + dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); + return 0; + } + + dns_scope_check_conflicts(t->scope, p); + + t->block_gc++; + dns_transaction_process_reply(t, p); + t->block_gc--; + + /* If the response wasn't useful, then complete the transition + * now. After all, we are the worst feature set now with TCP + * sockets, and there's really no point in retrying. */ + if (t->state == DNS_TRANSACTION_PENDING) + dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); + else + dns_transaction_gc(t); + + return 0; +} + +static int dns_transaction_open_tcp(DnsTransaction *t) { + _cleanup_close_ int fd = -1; + int r; + + assert(t); + + dns_transaction_close_connection(t); + + switch (t->scope->protocol) { + + case DNS_PROTOCOL_DNS: + r = dns_transaction_pick_server(t); + if (r < 0) + return r; + + if (!dns_server_dnssec_supported(t->server) && dns_type_is_dnssec(t->key->type)) + return -EOPNOTSUPP; + + r = dns_server_adjust_opt(t->server, t->sent, t->current_feature_level); + if (r < 0) + return r; + + fd = dns_scope_socket_tcp(t->scope, AF_UNSPEC, NULL, t->server, 53); + break; + + case DNS_PROTOCOL_LLMNR: + /* When we already received a reply to this (but it was truncated), send to its sender address */ + if (t->received) + fd = dns_scope_socket_tcp(t->scope, t->received->family, &t->received->sender, NULL, t->received->sender_port); + else { + union in_addr_union address; + int family = AF_UNSPEC; + + /* Otherwise, try to talk to the owner of a + * the IP address, in case this is a reverse + * PTR lookup */ + + r = dns_name_address(dns_resource_key_name(t->key), &family, &address); + if (r < 0) + return r; + if (r == 0) + return -EINVAL; + if (family != t->scope->family) + return -ESRCH; + + fd = dns_scope_socket_tcp(t->scope, family, &address, NULL, LLMNR_PORT); + } + + break; + + default: + return -EAFNOSUPPORT; + } + + if (fd < 0) + return fd; + + r = dns_stream_new(t->scope->manager, &t->stream, t->scope->protocol, fd); + if (r < 0) + return r; + fd = -1; + + r = dns_stream_write_packet(t->stream, t->sent); + if (r < 0) { + t->stream = dns_stream_unref(t->stream); + return r; + } + + t->stream->complete = on_stream_complete; + t->stream->transaction = t; + + /* The interface index is difficult to determine if we are + * connecting to the local host, hence fill this in right away + * instead of determining it from the socket */ + t->stream->ifindex = dns_scope_ifindex(t->scope); + + dns_transaction_reset_answer(t); + + t->tried_stream = true; + + return 0; +} + +static void dns_transaction_cache_answer(DnsTransaction *t) { + assert(t); + + /* For mDNS we cache whenever we get the packet, rather than + * in each transaction. */ + if (!IN_SET(t->scope->protocol, DNS_PROTOCOL_DNS, DNS_PROTOCOL_LLMNR)) + return; + + /* Caching disabled? */ + if (!t->scope->manager->enable_cache) + return; + + /* We never cache if this packet is from the local host, under + * the assumption that a locally running DNS server would + * cache this anyway, and probably knows better when to flush + * the cache then we could. */ + if (!DNS_PACKET_SHALL_CACHE(t->received)) + return; + + dns_cache_put(&t->scope->cache, + t->key, + t->answer_rcode, + t->answer, + t->answer_authenticated, + t->answer_nsec_ttl, + 0, + t->received->family, + &t->received->sender); +} + +static bool dns_transaction_dnssec_is_live(DnsTransaction *t) { + DnsTransaction *dt; + Iterator i; + + assert(t); + + SET_FOREACH(dt, t->dnssec_transactions, i) + if (DNS_TRANSACTION_IS_LIVE(dt->state)) + return true; + + return false; +} + +static int dns_transaction_dnssec_ready(DnsTransaction *t) { + DnsTransaction *dt; + Iterator i; + + assert(t); + + /* Checks whether the auxiliary DNSSEC transactions of our transaction have completed, or are still + * ongoing. Returns 0, if we aren't ready for the DNSSEC validation, positive if we are. */ + + SET_FOREACH(dt, t->dnssec_transactions, i) { + + switch (dt->state) { + + case DNS_TRANSACTION_NULL: + case DNS_TRANSACTION_PENDING: + case DNS_TRANSACTION_VALIDATING: + /* Still ongoing */ + return 0; + + case DNS_TRANSACTION_RCODE_FAILURE: + if (!IN_SET(dt->answer_rcode, DNS_RCODE_NXDOMAIN, DNS_RCODE_SERVFAIL)) { + log_debug("Auxiliary DNSSEC RR query failed with rcode=%s.", dns_rcode_to_string(dt->answer_rcode)); + goto fail; + } + + /* Fall-through: NXDOMAIN/SERVFAIL is good enough for us. This is because some DNS servers + * erronously return NXDOMAIN/SERVFAIL for empty non-terminals (Akamai...) or missing DS + * records (Facebook), and we need to handle that nicely, when asking for parent SOA or similar + * RRs to make unsigned proofs. */ + + case DNS_TRANSACTION_SUCCESS: + /* All good. */ + break; + + case DNS_TRANSACTION_DNSSEC_FAILED: + /* We handle DNSSEC failures different from other errors, as we care about the DNSSEC + * validationr result */ + + log_debug("Auxiliary DNSSEC RR query failed validation: %s", dnssec_result_to_string(dt->answer_dnssec_result)); + t->answer_dnssec_result = dt->answer_dnssec_result; /* Copy error code over */ + dns_transaction_complete(t, DNS_TRANSACTION_DNSSEC_FAILED); + return 0; + + + default: + log_debug("Auxiliary DNSSEC RR query failed with %s", dns_transaction_state_to_string(dt->state)); + goto fail; + } + } + + /* All is ready, we can go and validate */ + return 1; + +fail: + t->answer_dnssec_result = DNSSEC_FAILED_AUXILIARY; + dns_transaction_complete(t, DNS_TRANSACTION_DNSSEC_FAILED); + return 0; +} + +static void dns_transaction_process_dnssec(DnsTransaction *t) { + int r; + + assert(t); + + /* Are there ongoing DNSSEC transactions? If so, let's wait for them. */ + r = dns_transaction_dnssec_ready(t); + if (r < 0) + goto fail; + if (r == 0) /* We aren't ready yet (or one of our auxiliary transactions failed, and we shouldn't validate now */ + return; + + /* See if we learnt things from the additional DNSSEC transactions, that we didn't know before, and better + * restart the lookup immediately. */ + r = dns_transaction_maybe_restart(t); + if (r < 0) + goto fail; + if (r > 0) /* Transaction got restarted... */ + return; + + /* All our auxiliary DNSSEC transactions are complete now. Try + * to validate our RRset now. */ + r = dns_transaction_validate_dnssec(t); + if (r == -EBADMSG) { + dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); + return; + } + if (r < 0) + goto fail; + + if (t->answer_dnssec_result == DNSSEC_INCOMPATIBLE_SERVER && + t->scope->dnssec_mode == DNSSEC_YES) { + /* We are not in automatic downgrade mode, and the + * server is bad, refuse operation. */ + dns_transaction_complete(t, DNS_TRANSACTION_DNSSEC_FAILED); + return; + } + + if (!IN_SET(t->answer_dnssec_result, + _DNSSEC_RESULT_INVALID, /* No DNSSEC validation enabled */ + DNSSEC_VALIDATED, /* Answer is signed and validated successfully */ + DNSSEC_UNSIGNED, /* Answer is right-fully unsigned */ + DNSSEC_INCOMPATIBLE_SERVER)) { /* Server does not do DNSSEC (Yay, we are downgrade attack vulnerable!) */ + dns_transaction_complete(t, DNS_TRANSACTION_DNSSEC_FAILED); + return; + } + + if (t->answer_dnssec_result == DNSSEC_INCOMPATIBLE_SERVER) + dns_server_warn_downgrade(t->server); + + dns_transaction_cache_answer(t); + + if (t->answer_rcode == DNS_RCODE_SUCCESS) + dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS); + else + dns_transaction_complete(t, DNS_TRANSACTION_RCODE_FAILURE); + + return; + +fail: + t->answer_errno = -r; + dns_transaction_complete(t, DNS_TRANSACTION_ERRNO); +} + +static int dns_transaction_has_positive_answer(DnsTransaction *t, DnsAnswerFlags *flags) { + int r; + + assert(t); + + /* Checks whether the answer is positive, i.e. either a direct + * answer to the question, or a CNAME/DNAME for it */ + + r = dns_answer_match_key(t->answer, t->key, flags); + if (r != 0) + return r; + + r = dns_answer_find_cname_or_dname(t->answer, t->key, NULL, flags); + if (r != 0) + return r; + + return false; +} + +static int dns_transaction_fix_rcode(DnsTransaction *t) { + int r; + + assert(t); + + /* Fix up the RCODE to SUCCESS if we get at least one matching RR in a response. Note that this contradicts the + * DNS RFCs a bit. Specifically, RFC 6604 Section 3 clarifies that the RCODE shall say something about a + * CNAME/DNAME chain element coming after the last chain element contained in the message, and not the first + * one included. However, it also indicates that not all DNS servers implement this correctly. Moreover, when + * using DNSSEC we usually only can prove the first element of a CNAME/DNAME chain anyway, hence let's settle + * on always processing the RCODE as referring to the immediate look-up we do, i.e. the first element of a + * CNAME/DNAME chain. This way, we uniformly handle CNAME/DNAME chains, regardless if the DNS server + * incorrectly implements RCODE, whether DNSSEC is in use, or whether the DNS server only supplied us with an + * incomplete CNAME/DNAME chain. + * + * Or in other words: if we get at least one positive reply in a message we patch NXDOMAIN to become SUCCESS, + * and then rely on the CNAME chasing logic to figure out that there's actually a CNAME error with a new + * lookup. */ + + if (t->answer_rcode != DNS_RCODE_NXDOMAIN) + return 0; + + r = dns_transaction_has_positive_answer(t, NULL); + if (r <= 0) + return r; + + t->answer_rcode = DNS_RCODE_SUCCESS; + return 0; +} + +void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) { + usec_t ts; + int r; + + assert(t); + assert(p); + assert(t->scope); + assert(t->scope->manager); + + if (t->state != DNS_TRANSACTION_PENDING) + return; + + /* Note that this call might invalidate the query. Callers + * should hence not attempt to access the query or transaction + * after calling this function. */ + + log_debug("Processing incoming packet on transaction %" PRIu16".", t->id); + + switch (t->scope->protocol) { + + case DNS_PROTOCOL_LLMNR: + /* For LLMNR we will not accept any packets from other interfaces */ + + if (p->ifindex != dns_scope_ifindex(t->scope)) + return; + + if (p->family != t->scope->family) + return; + + /* Tentative packets are not full responses but still + * useful for identifying uniqueness conflicts during + * probing. */ + if (DNS_PACKET_LLMNR_T(p)) { + dns_transaction_tentative(t, p); + return; + } + + break; + + case DNS_PROTOCOL_MDNS: + /* For mDNS we will not accept any packets from other interfaces */ + + if (p->ifindex != dns_scope_ifindex(t->scope)) + return; + + if (p->family != t->scope->family) + return; + + break; + + case DNS_PROTOCOL_DNS: + /* Note that we do not need to verify the + * addresses/port numbers of incoming traffic, as we + * invoked connect() on our UDP socket in which case + * the kernel already does the needed verification for + * us. */ + break; + + default: + assert_not_reached("Invalid DNS protocol."); + } + + if (t->received != p) { + dns_packet_unref(t->received); + t->received = dns_packet_ref(p); + } + + t->answer_source = DNS_TRANSACTION_NETWORK; + + if (p->ipproto == IPPROTO_TCP) { + if (DNS_PACKET_TC(p)) { + /* Truncated via TCP? Somebody must be fucking with us */ + dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); + return; + } + + if (DNS_PACKET_ID(p) != t->id) { + /* Not the reply to our query? Somebody must be fucking with us */ + dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); + return; + } + } + + assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &ts) >= 0); + + switch (t->scope->protocol) { + + case DNS_PROTOCOL_DNS: + assert(t->server); + + if (IN_SET(DNS_PACKET_RCODE(p), DNS_RCODE_FORMERR, DNS_RCODE_SERVFAIL, DNS_RCODE_NOTIMP)) { + + /* Request failed, immediately try again with reduced features */ + + if (t->current_feature_level <= DNS_SERVER_FEATURE_LEVEL_WORST) { + /* This was already at the lowest possible feature level? If so, we can't downgrade + * this transaction anymore, hence let's process the response, and accept the rcode. */ + log_debug("Server returned error: %s", dns_rcode_to_string(DNS_PACKET_RCODE(p))); + break; + } + + /* Reduce this feature level by one and try again. */ + t->clamp_feature_level = t->current_feature_level - 1; + + log_debug("Server returned error %s, retrying transaction with reduced feature level %s.", + dns_rcode_to_string(DNS_PACKET_RCODE(p)), + dns_server_feature_level_to_string(t->clamp_feature_level)); + + dns_transaction_retry(t, false /* use the same server */); + return; + } else if (DNS_PACKET_TC(p)) + dns_server_packet_truncated(t->server, t->current_feature_level); + + break; + + case DNS_PROTOCOL_LLMNR: + case DNS_PROTOCOL_MDNS: + dns_scope_packet_received(t->scope, ts - t->start_usec); + break; + + default: + assert_not_reached("Invalid DNS protocol."); + } + + if (DNS_PACKET_TC(p)) { + + /* Truncated packets for mDNS are not allowed. Give up immediately. */ + if (t->scope->protocol == DNS_PROTOCOL_MDNS) { + dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); + return; + } + + log_debug("Reply truncated, retrying via TCP."); + + /* Response was truncated, let's try again with good old TCP */ + r = dns_transaction_open_tcp(t); + if (r == -ESRCH) { + /* No servers found? Damn! */ + dns_transaction_complete(t, DNS_TRANSACTION_NO_SERVERS); + return; + } + if (r == -EOPNOTSUPP) { + /* Tried to ask for DNSSEC RRs, on a server that doesn't do DNSSEC */ + dns_transaction_complete(t, DNS_TRANSACTION_RR_TYPE_UNSUPPORTED); + return; + } + if (r < 0) { + /* On LLMNR, if we cannot connect to the host, + * we immediately give up */ + if (t->scope->protocol != DNS_PROTOCOL_DNS) + goto fail; + + /* On DNS, couldn't send? Try immediately again, with a new server */ + dns_transaction_retry(t, true); + } + + return; + } + + /* After the superficial checks, actually parse the message. */ + r = dns_packet_extract(p); + if (r < 0) { + dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); + return; + } + + if (t->server) { + /* Report that we successfully received a valid packet with a good rcode after we initially got a bad + * rcode and subsequently downgraded the protocol */ + + if (IN_SET(DNS_PACKET_RCODE(p), DNS_RCODE_SUCCESS, DNS_RCODE_NXDOMAIN) && + t->clamp_feature_level != _DNS_SERVER_FEATURE_LEVEL_INVALID) + dns_server_packet_rcode_downgrade(t->server, t->clamp_feature_level); + + /* Report that the OPT RR was missing */ + if (!p->opt) + dns_server_packet_bad_opt(t->server, t->current_feature_level); + + /* Report that we successfully received a packet */ + dns_server_packet_received(t->server, p->ipproto, t->current_feature_level, ts - t->start_usec, p->size); + } + + /* See if we know things we didn't know before that indicate we better restart the lookup immediately. */ + r = dns_transaction_maybe_restart(t); + if (r < 0) + goto fail; + if (r > 0) /* Transaction got restarted... */ + return; + + if (IN_SET(t->scope->protocol, DNS_PROTOCOL_DNS, DNS_PROTOCOL_LLMNR)) { + + /* Only consider responses with equivalent query section to the request */ + r = dns_packet_is_reply_for(p, t->key); + if (r < 0) + goto fail; + if (r == 0) { + dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); + return; + } + + /* Install the answer as answer to the transaction */ + dns_answer_unref(t->answer); + t->answer = dns_answer_ref(p->answer); + t->answer_rcode = DNS_PACKET_RCODE(p); + t->answer_dnssec_result = _DNSSEC_RESULT_INVALID; + t->answer_authenticated = false; + + r = dns_transaction_fix_rcode(t); + if (r < 0) + goto fail; + + /* Block GC while starting requests for additional DNSSEC RRs */ + t->block_gc++; + r = dns_transaction_request_dnssec_keys(t); + t->block_gc--; + + /* Maybe the transaction is ready for GC'ing now? If so, free it and return. */ + if (!dns_transaction_gc(t)) + return; + + /* Requesting additional keys might have resulted in + * this transaction to fail, since the auxiliary + * request failed for some reason. If so, we are not + * in pending state anymore, and we should exit + * quickly. */ + if (t->state != DNS_TRANSACTION_PENDING) + return; + if (r < 0) + goto fail; + if (r > 0) { + /* There are DNSSEC transactions pending now. Update the state accordingly. */ + t->state = DNS_TRANSACTION_VALIDATING; + dns_transaction_close_connection(t); + dns_transaction_stop_timeout(t); + return; + } + } + + dns_transaction_process_dnssec(t); + return; + +fail: + t->answer_errno = -r; + dns_transaction_complete(t, DNS_TRANSACTION_ERRNO); +} + +static int on_dns_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) { + _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; + DnsTransaction *t = userdata; + int r; + + assert(t); + assert(t->scope); + + r = manager_recv(t->scope->manager, fd, DNS_PROTOCOL_DNS, &p); + if (ERRNO_IS_DISCONNECT(-r)) { + usec_t usec; + + /* UDP connection failure get reported via ICMP and then are possible delivered to us on the next + * recvmsg(). Treat this like a lost packet. */ + + log_debug_errno(r, "Connection failure for DNS UDP packet: %m"); + assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &usec) >= 0); + dns_server_packet_lost(t->server, IPPROTO_UDP, t->current_feature_level, usec - t->start_usec); + + dns_transaction_retry(t, true); + return 0; + } + if (r < 0) { + dns_transaction_complete(t, DNS_TRANSACTION_ERRNO); + t->answer_errno = -r; + return 0; + } + + r = dns_packet_validate_reply(p); + if (r < 0) { + log_debug_errno(r, "Received invalid DNS packet as response, ignoring: %m"); + return 0; + } + if (r == 0) { + log_debug("Received inappropriate DNS packet as response, ignoring."); + return 0; + } + + if (DNS_PACKET_ID(p) != t->id) { + log_debug("Received packet with incorrect transaction ID, ignoring."); + return 0; + } + + dns_transaction_process_reply(t, p); + return 0; +} + +static int dns_transaction_emit_udp(DnsTransaction *t) { + int r; + + assert(t); + + if (t->scope->protocol == DNS_PROTOCOL_DNS) { + + r = dns_transaction_pick_server(t); + if (r < 0) + return r; + + if (t->current_feature_level < DNS_SERVER_FEATURE_LEVEL_UDP) + return -EAGAIN; + + if (!dns_server_dnssec_supported(t->server) && dns_type_is_dnssec(t->key->type)) + return -EOPNOTSUPP; + + if (r > 0 || t->dns_udp_fd < 0) { /* Server changed, or no connection yet. */ + int fd; + + dns_transaction_close_connection(t); + + fd = dns_scope_socket_udp(t->scope, t->server, 53); + if (fd < 0) + return fd; + + r = sd_event_add_io(t->scope->manager->event, &t->dns_udp_event_source, fd, EPOLLIN, on_dns_packet, t); + if (r < 0) { + safe_close(fd); + return r; + } + + (void) sd_event_source_set_description(t->dns_udp_event_source, "dns-transaction-udp"); + t->dns_udp_fd = fd; + } + + r = dns_server_adjust_opt(t->server, t->sent, t->current_feature_level); + if (r < 0) + return r; + } else + dns_transaction_close_connection(t); + + r = dns_scope_emit_udp(t->scope, t->dns_udp_fd, t->sent); + if (r < 0) + return r; + + dns_transaction_reset_answer(t); + + return 0; +} + +static int on_transaction_timeout(sd_event_source *s, usec_t usec, void *userdata) { + DnsTransaction *t = userdata; + + assert(s); + assert(t); + + if (!t->initial_jitter_scheduled || t->initial_jitter_elapsed) { + /* Timeout reached? Increase the timeout for the server used */ + switch (t->scope->protocol) { + + case DNS_PROTOCOL_DNS: + assert(t->server); + dns_server_packet_lost(t->server, t->stream ? IPPROTO_TCP : IPPROTO_UDP, t->current_feature_level, usec - t->start_usec); + break; + + case DNS_PROTOCOL_LLMNR: + case DNS_PROTOCOL_MDNS: + dns_scope_packet_lost(t->scope, usec - t->start_usec); + break; + + default: + assert_not_reached("Invalid DNS protocol."); + } + + if (t->initial_jitter_scheduled) + t->initial_jitter_elapsed = true; + } + + log_debug("Timeout reached on transaction %" PRIu16 ".", t->id); + + dns_transaction_retry(t, true); + return 0; +} + +static usec_t transaction_get_resend_timeout(DnsTransaction *t) { + assert(t); + assert(t->scope); + + switch (t->scope->protocol) { + + case DNS_PROTOCOL_DNS: + assert(t->server); + return t->server->resend_timeout; + + case DNS_PROTOCOL_MDNS: + assert(t->n_attempts > 0); + return (1 << (t->n_attempts - 1)) * USEC_PER_SEC; + + case DNS_PROTOCOL_LLMNR: + return t->scope->resend_timeout; + + default: + assert_not_reached("Invalid DNS protocol."); + } +} + +static int dns_transaction_prepare(DnsTransaction *t, usec_t ts) { + int r; + + assert(t); + + dns_transaction_stop_timeout(t); + + r = dns_scope_network_good(t->scope); + if (r < 0) + return r; + if (r == 0) { + dns_transaction_complete(t, DNS_TRANSACTION_NETWORK_DOWN); + return 0; + } + + if (t->n_attempts >= TRANSACTION_ATTEMPTS_MAX(t->scope->protocol)) { + dns_transaction_complete(t, DNS_TRANSACTION_ATTEMPTS_MAX_REACHED); + return 0; + } + + if (t->scope->protocol == DNS_PROTOCOL_LLMNR && t->tried_stream) { + /* If we already tried via a stream, then we don't + * retry on LLMNR. See RFC 4795, Section 2.7. */ + dns_transaction_complete(t, DNS_TRANSACTION_ATTEMPTS_MAX_REACHED); + return 0; + } + + t->n_attempts++; + t->start_usec = ts; + + dns_transaction_reset_answer(t); + dns_transaction_flush_dnssec_transactions(t); + + /* Check the trust anchor. Do so only on classic DNS, since DNSSEC does not apply otherwise. */ + if (t->scope->protocol == DNS_PROTOCOL_DNS) { + r = dns_trust_anchor_lookup_positive(&t->scope->manager->trust_anchor, t->key, &t->answer); + if (r < 0) + return r; + if (r > 0) { + t->answer_rcode = DNS_RCODE_SUCCESS; + t->answer_source = DNS_TRANSACTION_TRUST_ANCHOR; + t->answer_authenticated = true; + dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS); + return 0; + } + + if (dns_name_is_root(dns_resource_key_name(t->key)) && + t->key->type == DNS_TYPE_DS) { + + /* Hmm, this is a request for the root DS? A + * DS RR doesn't exist in the root zone, and + * if our trust anchor didn't know it either, + * this means we cannot do any DNSSEC logic + * anymore. */ + + if (t->scope->dnssec_mode == DNSSEC_ALLOW_DOWNGRADE) { + /* We are in downgrade mode. In this + * case, synthesize an unsigned empty + * response, so that the any lookup + * depending on this one can continue + * assuming there was no DS, and hence + * the root zone was unsigned. */ + + t->answer_rcode = DNS_RCODE_SUCCESS; + t->answer_source = DNS_TRANSACTION_TRUST_ANCHOR; + t->answer_authenticated = false; + dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS); + } else + /* If we are not in downgrade mode, + * then fail the lookup, because we + * cannot reasonably answer it. There + * might be DS RRs, but we don't know + * them, and the DNS server won't tell + * them to us (and even if it would, + * we couldn't validate and trust them. */ + dns_transaction_complete(t, DNS_TRANSACTION_NO_TRUST_ANCHOR); + + return 0; + } + } + + /* Check the zone, but only if this transaction is not used + * for probing or verifying a zone item. */ + if (set_isempty(t->notify_zone_items)) { + + r = dns_zone_lookup(&t->scope->zone, t->key, dns_scope_ifindex(t->scope), &t->answer, NULL, NULL); + if (r < 0) + return r; + if (r > 0) { + t->answer_rcode = DNS_RCODE_SUCCESS; + t->answer_source = DNS_TRANSACTION_ZONE; + t->answer_authenticated = true; + dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS); + return 0; + } + } + + /* Check the cache, but only if this transaction is not used + * for probing or verifying a zone item. */ + if (set_isempty(t->notify_zone_items)) { + + /* Before trying the cache, let's make sure we figured out a + * server to use. Should this cause a change of server this + * might flush the cache. */ + dns_scope_get_dns_server(t->scope); + + /* Let's then prune all outdated entries */ + dns_cache_prune(&t->scope->cache); + + r = dns_cache_lookup(&t->scope->cache, t->key, t->clamp_ttl, &t->answer_rcode, &t->answer, &t->answer_authenticated); + if (r < 0) + return r; + if (r > 0) { + t->answer_source = DNS_TRANSACTION_CACHE; + if (t->answer_rcode == DNS_RCODE_SUCCESS) + dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS); + else + dns_transaction_complete(t, DNS_TRANSACTION_RCODE_FAILURE); + return 0; + } + } + + return 1; +} + +static int dns_transaction_make_packet_mdns(DnsTransaction *t) { + + _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; + bool add_known_answers = false; + DnsTransaction *other; + unsigned qdcount; + usec_t ts; + int r; + + assert(t); + assert(t->scope->protocol == DNS_PROTOCOL_MDNS); + + /* Discard any previously prepared packet, so we can start over and coalesce again */ + t->sent = dns_packet_unref(t->sent); + + r = dns_packet_new_query(&p, t->scope->protocol, 0, false); + if (r < 0) + return r; + + r = dns_packet_append_key(p, t->key, NULL); + if (r < 0) + return r; + + qdcount = 1; + + if (dns_key_is_shared(t->key)) + add_known_answers = true; + + /* + * For mDNS, we want to coalesce as many open queries in pending transactions into one single + * query packet on the wire as possible. To achieve that, we iterate through all pending transactions + * in our current scope, and see whether their timing contraints allow them to be sent. + */ + + assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &ts) >= 0); + + LIST_FOREACH(transactions_by_scope, other, t->scope->transactions) { + + /* Skip ourselves */ + if (other == t) + continue; + + if (other->state != DNS_TRANSACTION_PENDING) + continue; + + if (other->next_attempt_after > ts) + continue; + + if (qdcount >= UINT16_MAX) + break; + + r = dns_packet_append_key(p, other->key, NULL); + + /* + * If we can't stuff more questions into the packet, just give up. + * One of the 'other' transactions will fire later and take care of the rest. + */ + if (r == -EMSGSIZE) + break; + + if (r < 0) + return r; + + r = dns_transaction_prepare(other, ts); + if (r <= 0) + continue; + + ts += transaction_get_resend_timeout(other); + + r = sd_event_add_time( + other->scope->manager->event, + &other->timeout_event_source, + clock_boottime_or_monotonic(), + ts, 0, + on_transaction_timeout, other); + if (r < 0) + return r; + + (void) sd_event_source_set_description(t->timeout_event_source, "dns-transaction-timeout"); + + other->state = DNS_TRANSACTION_PENDING; + other->next_attempt_after = ts; + + qdcount++; + + if (dns_key_is_shared(other->key)) + add_known_answers = true; + } + + DNS_PACKET_HEADER(p)->qdcount = htobe16(qdcount); + + /* Append known answer section if we're asking for any shared record */ + if (add_known_answers) { + r = dns_cache_export_shared_to_packet(&t->scope->cache, p); + if (r < 0) + return r; + } + + t->sent = p; + p = NULL; + + return 0; +} + +static int dns_transaction_make_packet(DnsTransaction *t) { + _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; + int r; + + assert(t); + + if (t->scope->protocol == DNS_PROTOCOL_MDNS) + return dns_transaction_make_packet_mdns(t); + + if (t->sent) + return 0; + + r = dns_packet_new_query(&p, t->scope->protocol, 0, t->scope->dnssec_mode != DNSSEC_NO); + if (r < 0) + return r; + + r = dns_packet_append_key(p, t->key, NULL); + if (r < 0) + return r; + + DNS_PACKET_HEADER(p)->qdcount = htobe16(1); + DNS_PACKET_HEADER(p)->id = t->id; + + t->sent = p; + p = NULL; + + return 0; +} + +int dns_transaction_go(DnsTransaction *t) { + usec_t ts; + int r; + char key_str[DNS_RESOURCE_KEY_STRING_MAX]; + + assert(t); + + /* Returns > 0 if the transaction is now pending, returns 0 if could be processed immediately and has finished + * now. */ + + assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &ts) >= 0); + + r = dns_transaction_prepare(t, ts); + if (r <= 0) + return r; + + log_debug("Transaction %" PRIu16 " for <%s> scope %s on %s/%s.", + t->id, + dns_resource_key_to_string(t->key, key_str, sizeof key_str), + dns_protocol_to_string(t->scope->protocol), + t->scope->link ? t->scope->link->name : "*", + af_to_name_short(t->scope->family)); + + if (!t->initial_jitter_scheduled && + (t->scope->protocol == DNS_PROTOCOL_LLMNR || + t->scope->protocol == DNS_PROTOCOL_MDNS)) { + usec_t jitter, accuracy; + + /* RFC 4795 Section 2.7 suggests all queries should be + * delayed by a random time from 0 to JITTER_INTERVAL. */ + + t->initial_jitter_scheduled = true; + + random_bytes(&jitter, sizeof(jitter)); + + switch (t->scope->protocol) { + + case DNS_PROTOCOL_LLMNR: + jitter %= LLMNR_JITTER_INTERVAL_USEC; + accuracy = LLMNR_JITTER_INTERVAL_USEC; + break; + + case DNS_PROTOCOL_MDNS: + jitter %= MDNS_JITTER_RANGE_USEC; + jitter += MDNS_JITTER_MIN_USEC; + accuracy = MDNS_JITTER_RANGE_USEC; + break; + default: + assert_not_reached("bad protocol"); + } + + r = sd_event_add_time( + t->scope->manager->event, + &t->timeout_event_source, + clock_boottime_or_monotonic(), + ts + jitter, accuracy, + on_transaction_timeout, t); + if (r < 0) + return r; + + (void) sd_event_source_set_description(t->timeout_event_source, "dns-transaction-timeout"); + + t->n_attempts = 0; + t->next_attempt_after = ts; + t->state = DNS_TRANSACTION_PENDING; + + log_debug("Delaying %s transaction for " USEC_FMT "us.", dns_protocol_to_string(t->scope->protocol), jitter); + return 0; + } + + /* Otherwise, we need to ask the network */ + r = dns_transaction_make_packet(t); + if (r < 0) + return r; + + if (t->scope->protocol == DNS_PROTOCOL_LLMNR && + (dns_name_endswith(dns_resource_key_name(t->key), "in-addr.arpa") > 0 || + dns_name_endswith(dns_resource_key_name(t->key), "ip6.arpa") > 0)) { + + /* RFC 4795, Section 2.4. says reverse lookups shall + * always be made via TCP on LLMNR */ + r = dns_transaction_open_tcp(t); + } else { + /* Try via UDP, and if that fails due to large size or lack of + * support try via TCP */ + r = dns_transaction_emit_udp(t); + if (r == -EMSGSIZE) + log_debug("Sending query via TCP since it is too large."); + if (r == -EAGAIN) + log_debug("Sending query via TCP since server doesn't support UDP."); + if (r == -EMSGSIZE || r == -EAGAIN) + r = dns_transaction_open_tcp(t); + } + + if (r == -ESRCH) { + /* No servers to send this to? */ + dns_transaction_complete(t, DNS_TRANSACTION_NO_SERVERS); + return 0; + } + if (r == -EOPNOTSUPP) { + /* Tried to ask for DNSSEC RRs, on a server that doesn't do DNSSEC */ + dns_transaction_complete(t, DNS_TRANSACTION_RR_TYPE_UNSUPPORTED); + return 0; + } + if (t->scope->protocol == DNS_PROTOCOL_LLMNR && ERRNO_IS_DISCONNECT(-r)) { + /* On LLMNR, if we cannot connect to a host via TCP when doing reverse lookups. This means we cannot + * answer this request with this protocol. */ + dns_transaction_complete(t, DNS_TRANSACTION_NOT_FOUND); + return 0; + } + if (r < 0) { + if (t->scope->protocol != DNS_PROTOCOL_DNS) + return r; + + /* Couldn't send? Try immediately again, with a new server */ + dns_scope_next_dns_server(t->scope); + + return dns_transaction_go(t); + } + + ts += transaction_get_resend_timeout(t); + + r = sd_event_add_time( + t->scope->manager->event, + &t->timeout_event_source, + clock_boottime_or_monotonic(), + ts, 0, + on_transaction_timeout, t); + if (r < 0) + return r; + + (void) sd_event_source_set_description(t->timeout_event_source, "dns-transaction-timeout"); + + t->state = DNS_TRANSACTION_PENDING; + t->next_attempt_after = ts; + + return 1; +} + +static int dns_transaction_find_cyclic(DnsTransaction *t, DnsTransaction *aux) { + DnsTransaction *n; + Iterator i; + int r; + + assert(t); + assert(aux); + + /* Try to find cyclic dependencies between transaction objects */ + + if (t == aux) + return 1; + + SET_FOREACH(n, aux->dnssec_transactions, i) { + r = dns_transaction_find_cyclic(t, n); + if (r != 0) + return r; + } + + return 0; +} + +static int dns_transaction_add_dnssec_transaction(DnsTransaction *t, DnsResourceKey *key, DnsTransaction **ret) { + DnsTransaction *aux; + int r; + + assert(t); + assert(ret); + assert(key); + + aux = dns_scope_find_transaction(t->scope, key, true); + if (!aux) { + r = dns_transaction_new(&aux, t->scope, key); + if (r < 0) + return r; + } else { + if (set_contains(t->dnssec_transactions, aux)) { + *ret = aux; + return 0; + } + + r = dns_transaction_find_cyclic(t, aux); + if (r < 0) + return r; + if (r > 0) { + char s[DNS_RESOURCE_KEY_STRING_MAX], saux[DNS_RESOURCE_KEY_STRING_MAX]; + + log_debug("Potential cyclic dependency, refusing to add transaction %" PRIu16 " (%s) as dependency for %" PRIu16 " (%s).", + aux->id, + dns_resource_key_to_string(t->key, s, sizeof s), + t->id, + dns_resource_key_to_string(aux->key, saux, sizeof saux)); + + return -ELOOP; + } + } + + r = set_ensure_allocated(&t->dnssec_transactions, NULL); + if (r < 0) + goto gc; + + r = set_ensure_allocated(&aux->notify_transactions, NULL); + if (r < 0) + goto gc; + + r = set_ensure_allocated(&aux->notify_transactions_done, NULL); + if (r < 0) + goto gc; + + r = set_put(t->dnssec_transactions, aux); + if (r < 0) + goto gc; + + r = set_put(aux->notify_transactions, t); + if (r < 0) { + (void) set_remove(t->dnssec_transactions, aux); + goto gc; + } + + *ret = aux; + return 1; + +gc: + dns_transaction_gc(aux); + return r; +} + +static int dns_transaction_request_dnssec_rr(DnsTransaction *t, DnsResourceKey *key) { + _cleanup_(dns_answer_unrefp) DnsAnswer *a = NULL; + DnsTransaction *aux; + int r; + + assert(t); + assert(key); + + /* Try to get the data from the trust anchor */ + r = dns_trust_anchor_lookup_positive(&t->scope->manager->trust_anchor, key, &a); + if (r < 0) + return r; + if (r > 0) { + r = dns_answer_extend(&t->validated_keys, a); + if (r < 0) + return r; + + return 0; + } + + /* This didn't work, ask for it via the network/cache then. */ + r = dns_transaction_add_dnssec_transaction(t, key, &aux); + if (r == -ELOOP) /* This would result in a cyclic dependency */ + return 0; + if (r < 0) + return r; + + if (aux->state == DNS_TRANSACTION_NULL) { + r = dns_transaction_go(aux); + if (r < 0) + return r; + } + + return 1; +} + +static int dns_transaction_negative_trust_anchor_lookup(DnsTransaction *t, const char *name) { + int r; + + assert(t); + + /* Check whether the specified name is in the NTA + * database, either in the global one, or the link-local + * one. */ + + r = dns_trust_anchor_lookup_negative(&t->scope->manager->trust_anchor, name); + if (r != 0) + return r; + + if (!t->scope->link) + return 0; + + return set_contains(t->scope->link->dnssec_negative_trust_anchors, name); +} + +static int dns_transaction_has_unsigned_negative_answer(DnsTransaction *t) { + int r; + + assert(t); + + /* Checks whether the answer is negative, and lacks NSEC/NSEC3 + * RRs to prove it */ + + r = dns_transaction_has_positive_answer(t, NULL); + if (r < 0) + return r; + if (r > 0) + return false; + + /* Is this key explicitly listed as a negative trust anchor? + * If so, it's nothing we need to care about */ + r = dns_transaction_negative_trust_anchor_lookup(t, dns_resource_key_name(t->key)); + if (r < 0) + return r; + if (r > 0) + return false; + + /* The answer does not contain any RRs that match to the + * question. If so, let's see if there are any NSEC/NSEC3 RRs + * included. If not, the answer is unsigned. */ + + r = dns_answer_contains_nsec_or_nsec3(t->answer); + if (r < 0) + return r; + if (r > 0) + return false; + + return true; +} + +static int dns_transaction_is_primary_response(DnsTransaction *t, DnsResourceRecord *rr) { + int r; + + assert(t); + assert(rr); + + /* Check if the specified RR is the "primary" response, + * i.e. either matches the question precisely or is a + * CNAME/DNAME for it. */ + + r = dns_resource_key_match_rr(t->key, rr, NULL); + if (r != 0) + return r; + + return dns_resource_key_match_cname_or_dname(t->key, rr->key, NULL); +} + +static bool dns_transaction_dnssec_supported(DnsTransaction *t) { + assert(t); + + /* Checks whether our transaction's DNS server is assumed to be compatible with DNSSEC. Returns false as soon + * as we changed our mind about a server, and now believe it is incompatible with DNSSEC. */ + + if (t->scope->protocol != DNS_PROTOCOL_DNS) + return false; + + /* If we have picked no server, then we are working from the cache or some other source, and DNSSEC might well + * be supported, hence return true. */ + if (!t->server) + return true; + + /* Note that we do not check the feature level actually used for the transaction but instead the feature level + * the server is known to support currently, as the transaction feature level might be lower than what the + * server actually supports, since we might have downgraded this transaction's feature level because we got a + * SERVFAIL earlier and wanted to check whether downgrading fixes it. */ + + return dns_server_dnssec_supported(t->server); +} + +static bool dns_transaction_dnssec_supported_full(DnsTransaction *t) { + DnsTransaction *dt; + Iterator i; + + assert(t); + + /* Checks whether our transaction our any of the auxiliary transactions couldn't do DNSSEC. */ + + if (!dns_transaction_dnssec_supported(t)) + return false; + + SET_FOREACH(dt, t->dnssec_transactions, i) + if (!dns_transaction_dnssec_supported(dt)) + return false; + + return true; +} + +int dns_transaction_request_dnssec_keys(DnsTransaction *t) { + DnsResourceRecord *rr; + + int r; + + assert(t); + + /* + * Retrieve all auxiliary RRs for the answer we got, so that + * we can verify signatures or prove that RRs are rightfully + * unsigned. Specifically: + * + * - For RRSIG we get the matching DNSKEY + * - For DNSKEY we get the matching DS + * - For unsigned SOA/NS we get the matching DS + * - For unsigned CNAME/DNAME/DS we get the parent SOA RR + * - For other unsigned RRs we get the matching SOA RR + * - For SOA/NS queries with no matching response RR, and no NSEC/NSEC3, the DS RR + * - For DS queries with no matching response RRs, and no NSEC/NSEC3, the parent's SOA RR + * - For other queries with no matching response RRs, and no NSEC/NSEC3, the SOA RR + */ + + if (t->scope->dnssec_mode == DNSSEC_NO) + return 0; + if (t->answer_source != DNS_TRANSACTION_NETWORK) + return 0; /* We only need to validate stuff from the network */ + if (!dns_transaction_dnssec_supported(t)) + return 0; /* If we can't do DNSSEC anyway there's no point in geting the auxiliary RRs */ + + DNS_ANSWER_FOREACH(rr, t->answer) { + + if (dns_type_is_pseudo(rr->key->type)) + continue; + + /* If this RR is in the negative trust anchor, we don't need to validate it. */ + r = dns_transaction_negative_trust_anchor_lookup(t, dns_resource_key_name(rr->key)); + if (r < 0) + return r; + if (r > 0) + continue; + + switch (rr->key->type) { + + case DNS_TYPE_RRSIG: { + /* For each RRSIG we request the matching DNSKEY */ + _cleanup_(dns_resource_key_unrefp) DnsResourceKey *dnskey = NULL; + + /* If this RRSIG is about a DNSKEY RR and the + * signer is the same as the owner, then we + * already have the DNSKEY, and we don't have + * to look for more. */ + if (rr->rrsig.type_covered == DNS_TYPE_DNSKEY) { + r = dns_name_equal(rr->rrsig.signer, dns_resource_key_name(rr->key)); + if (r < 0) + return r; + if (r > 0) + continue; + } + + /* If the signer is not a parent of our + * original query, then this is about an + * auxiliary RRset, but not anything we asked + * for. In this case we aren't interested, + * because we don't want to request additional + * RRs for stuff we didn't really ask for, and + * also to avoid request loops, where + * additional RRs from one transaction result + * in another transaction whose additonal RRs + * point back to the original transaction, and + * we deadlock. */ + r = dns_name_endswith(dns_resource_key_name(t->key), rr->rrsig.signer); + if (r < 0) + return r; + if (r == 0) + continue; + + dnskey = dns_resource_key_new(rr->key->class, DNS_TYPE_DNSKEY, rr->rrsig.signer); + if (!dnskey) + return -ENOMEM; + + log_debug("Requesting DNSKEY to validate transaction %" PRIu16" (%s, RRSIG with key tag: %" PRIu16 ").", + t->id, dns_resource_key_name(rr->key), rr->rrsig.key_tag); + r = dns_transaction_request_dnssec_rr(t, dnskey); + if (r < 0) + return r; + break; + } + + case DNS_TYPE_DNSKEY: { + /* For each DNSKEY we request the matching DS */ + _cleanup_(dns_resource_key_unrefp) DnsResourceKey *ds = NULL; + + /* If the DNSKEY we are looking at is not for + * zone we are interested in, nor any of its + * parents, we aren't interested, and don't + * request it. After all, we don't want to end + * up in request loops, and want to keep + * additional traffic down. */ + + r = dns_name_endswith(dns_resource_key_name(t->key), dns_resource_key_name(rr->key)); + if (r < 0) + return r; + if (r == 0) + continue; + + ds = dns_resource_key_new(rr->key->class, DNS_TYPE_DS, dns_resource_key_name(rr->key)); + if (!ds) + return -ENOMEM; + + log_debug("Requesting DS to validate transaction %" PRIu16" (%s, DNSKEY with key tag: %" PRIu16 ").", + t->id, dns_resource_key_name(rr->key), dnssec_keytag(rr, false)); + r = dns_transaction_request_dnssec_rr(t, ds); + if (r < 0) + return r; + + break; + } + + case DNS_TYPE_SOA: + case DNS_TYPE_NS: { + _cleanup_(dns_resource_key_unrefp) DnsResourceKey *ds = NULL; + + /* For an unsigned SOA or NS, try to acquire + * the matching DS RR, as we are at a zone cut + * then, and whether a DS exists tells us + * whether the zone is signed. Do so only if + * this RR matches our original question, + * however. */ + + r = dns_resource_key_match_rr(t->key, rr, NULL); + if (r < 0) + return r; + if (r == 0) + continue; + + r = dnssec_has_rrsig(t->answer, rr->key); + if (r < 0) + return r; + if (r > 0) + continue; + + ds = dns_resource_key_new(rr->key->class, DNS_TYPE_DS, dns_resource_key_name(rr->key)); + if (!ds) + return -ENOMEM; + + log_debug("Requesting DS to validate transaction %" PRIu16 " (%s, unsigned SOA/NS RRset).", + t->id, dns_resource_key_name(rr->key)); + r = dns_transaction_request_dnssec_rr(t, ds); + if (r < 0) + return r; + + break; + } + + case DNS_TYPE_DS: + case DNS_TYPE_CNAME: + case DNS_TYPE_DNAME: { + _cleanup_(dns_resource_key_unrefp) DnsResourceKey *soa = NULL; + const char *name; + + /* CNAMEs and DNAMEs cannot be located at a + * zone apex, hence ask for the parent SOA for + * unsigned CNAME/DNAME RRs, maybe that's the + * apex. But do all that only if this is + * actually a response to our original + * question. + * + * Similar for DS RRs, which are signed when + * the parent SOA is signed. */ + + r = dns_transaction_is_primary_response(t, rr); + if (r < 0) + return r; + if (r == 0) + continue; + + r = dnssec_has_rrsig(t->answer, rr->key); + if (r < 0) + return r; + if (r > 0) + continue; + + r = dns_answer_has_dname_for_cname(t->answer, rr); + if (r < 0) + return r; + if (r > 0) + continue; + + name = dns_resource_key_name(rr->key); + r = dns_name_parent(&name); + if (r < 0) + return r; + if (r == 0) + continue; + + soa = dns_resource_key_new(rr->key->class, DNS_TYPE_SOA, name); + if (!soa) + return -ENOMEM; + + log_debug("Requesting parent SOA to validate transaction %" PRIu16 " (%s, unsigned CNAME/DNAME/DS RRset).", + t->id, dns_resource_key_name(rr->key)); + r = dns_transaction_request_dnssec_rr(t, soa); + if (r < 0) + return r; + + break; + } + + default: { + _cleanup_(dns_resource_key_unrefp) DnsResourceKey *soa = NULL; + + /* For other unsigned RRsets (including + * NSEC/NSEC3!), look for proof the zone is + * unsigned, by requesting the SOA RR of the + * zone. However, do so only if they are + * directly relevant to our original + * question. */ + + r = dns_transaction_is_primary_response(t, rr); + if (r < 0) + return r; + if (r == 0) + continue; + + r = dnssec_has_rrsig(t->answer, rr->key); + if (r < 0) + return r; + if (r > 0) + continue; + + soa = dns_resource_key_new(rr->key->class, DNS_TYPE_SOA, dns_resource_key_name(rr->key)); + if (!soa) + return -ENOMEM; + + log_debug("Requesting SOA to validate transaction %" PRIu16 " (%s, unsigned non-SOA/NS RRset <%s>).", + t->id, dns_resource_key_name(rr->key), dns_resource_record_to_string(rr)); + r = dns_transaction_request_dnssec_rr(t, soa); + if (r < 0) + return r; + break; + }} + } + + /* Above, we requested everything necessary to validate what + * we got. Now, let's request what we need to validate what we + * didn't get... */ + + r = dns_transaction_has_unsigned_negative_answer(t); + if (r < 0) + return r; + if (r > 0) { + const char *name; + uint16_t type = 0; + + name = dns_resource_key_name(t->key); + + /* If this was a SOA or NS request, then check if there's a DS RR for the same domain. Note that this + * could also be used as indication that we are not at a zone apex, but in real world setups there are + * too many broken DNS servers (Hello, incapdns.net!) where non-terminal zones return NXDOMAIN even + * though they have further children. If this was a DS request, then it's signed when the parent zone + * is signed, hence ask the parent SOA in that case. If this was any other RR then ask for the SOA RR, + * to see if that is signed. */ + + if (t->key->type == DNS_TYPE_DS) { + r = dns_name_parent(&name); + if (r > 0) { + type = DNS_TYPE_SOA; + log_debug("Requesting parent SOA to validate transaction %" PRIu16 " (%s, unsigned empty DS response).", + t->id, dns_resource_key_name(t->key)); + } else + name = NULL; + + } else if (IN_SET(t->key->type, DNS_TYPE_SOA, DNS_TYPE_NS)) { + + type = DNS_TYPE_DS; + log_debug("Requesting DS to validate transaction %" PRIu16 " (%s, unsigned empty SOA/NS response).", + t->id, dns_resource_key_name(t->key)); + + } else { + type = DNS_TYPE_SOA; + log_debug("Requesting SOA to validate transaction %" PRIu16 " (%s, unsigned empty non-SOA/NS/DS response).", + t->id, dns_resource_key_name(t->key)); + } + + if (name) { + _cleanup_(dns_resource_key_unrefp) DnsResourceKey *soa = NULL; + + soa = dns_resource_key_new(t->key->class, type, name); + if (!soa) + return -ENOMEM; + + r = dns_transaction_request_dnssec_rr(t, soa); + if (r < 0) + return r; + } + } + + return dns_transaction_dnssec_is_live(t); +} + +void dns_transaction_notify(DnsTransaction *t, DnsTransaction *source) { + assert(t); + assert(source); + + /* Invoked whenever any of our auxiliary DNSSEC transactions completed its work. If the state is still PENDING, + we are still in the loop that adds further DNSSEC transactions, hence don't check if we are ready yet. If + the state is VALIDATING however, we should check if we are complete now. */ + + if (t->state == DNS_TRANSACTION_VALIDATING) + dns_transaction_process_dnssec(t); +} + +static int dns_transaction_validate_dnskey_by_ds(DnsTransaction *t) { + DnsResourceRecord *rr; + int ifindex, r; + + assert(t); + + /* Add all DNSKEY RRs from the answer that are validated by DS + * RRs from the list of validated keys to the list of + * validated keys. */ + + DNS_ANSWER_FOREACH_IFINDEX(rr, ifindex, t->answer) { + + r = dnssec_verify_dnskey_by_ds_search(rr, t->validated_keys); + if (r < 0) + return r; + if (r == 0) + continue; + + /* If so, the DNSKEY is validated too. */ + r = dns_answer_add_extend(&t->validated_keys, rr, ifindex, DNS_ANSWER_AUTHENTICATED); + if (r < 0) + return r; + } + + return 0; +} + +static int dns_transaction_requires_rrsig(DnsTransaction *t, DnsResourceRecord *rr) { + int r; + + assert(t); + assert(rr); + + /* Checks if the RR we are looking for must be signed with an + * RRSIG. This is used for positive responses. */ + + if (t->scope->dnssec_mode == DNSSEC_NO) + return false; + + if (dns_type_is_pseudo(rr->key->type)) + return -EINVAL; + + r = dns_transaction_negative_trust_anchor_lookup(t, dns_resource_key_name(rr->key)); + if (r < 0) + return r; + if (r > 0) + return false; + + switch (rr->key->type) { + + case DNS_TYPE_RRSIG: + /* RRSIGs are the signatures themselves, they need no signing. */ + return false; + + case DNS_TYPE_SOA: + case DNS_TYPE_NS: { + DnsTransaction *dt; + Iterator i; + + /* For SOA or NS RRs we look for a matching DS transaction */ + + SET_FOREACH(dt, t->dnssec_transactions, i) { + + if (dt->key->class != rr->key->class) + continue; + if (dt->key->type != DNS_TYPE_DS) + continue; + + r = dns_name_equal(dns_resource_key_name(dt->key), dns_resource_key_name(rr->key)); + if (r < 0) + return r; + if (r == 0) + continue; + + /* We found a DS transactions for the SOA/NS + * RRs we are looking at. If it discovered signed DS + * RRs, then we need to be signed, too. */ + + if (!dt->answer_authenticated) + return false; + + return dns_answer_match_key(dt->answer, dt->key, NULL); + } + + /* We found nothing that proves this is safe to leave + * this unauthenticated, hence ask inist on + * authentication. */ + return true; + } + + case DNS_TYPE_DS: + case DNS_TYPE_CNAME: + case DNS_TYPE_DNAME: { + const char *parent = NULL; + DnsTransaction *dt; + Iterator i; + + /* + * CNAME/DNAME RRs cannot be located at a zone apex, hence look directly for the parent SOA. + * + * DS RRs are signed if the parent is signed, hence also look at the parent SOA + */ + + SET_FOREACH(dt, t->dnssec_transactions, i) { + + if (dt->key->class != rr->key->class) + continue; + if (dt->key->type != DNS_TYPE_SOA) + continue; + + if (!parent) { + parent = dns_resource_key_name(rr->key); + r = dns_name_parent(&parent); + if (r < 0) + return r; + if (r == 0) { + if (rr->key->type == DNS_TYPE_DS) + return true; + + /* A CNAME/DNAME without a parent? That's sooo weird. */ + log_debug("Transaction %" PRIu16 " claims CNAME/DNAME at root. Refusing.", t->id); + return -EBADMSG; + } + } + + r = dns_name_equal(dns_resource_key_name(dt->key), parent); + if (r < 0) + return r; + if (r == 0) + continue; + + return t->answer_authenticated; + } + + return true; + } + + default: { + DnsTransaction *dt; + Iterator i; + + /* Any other kind of RR (including DNSKEY/NSEC/NSEC3). Let's see if our SOA lookup was authenticated */ + + SET_FOREACH(dt, t->dnssec_transactions, i) { + + if (dt->key->class != rr->key->class) + continue; + if (dt->key->type != DNS_TYPE_SOA) + continue; + + r = dns_name_equal(dns_resource_key_name(dt->key), dns_resource_key_name(rr->key)); + if (r < 0) + return r; + if (r == 0) + continue; + + /* We found the transaction that was supposed to find + * the SOA RR for us. It was successful, but found no + * RR for us. This means we are not at a zone cut. In + * this case, we require authentication if the SOA + * lookup was authenticated too. */ + return t->answer_authenticated; + } + + return true; + }} +} + +static int dns_transaction_in_private_tld(DnsTransaction *t, const DnsResourceKey *key) { + DnsTransaction *dt; + const char *tld; + Iterator i; + int r; + + /* If DNSSEC downgrade mode is on, checks whether the + * specified RR is one level below a TLD we have proven not to + * exist. In such a case we assume that this is a private + * domain, and permit it. + * + * This detects cases like the Fritz!Box router networks. Each + * Fritz!Box router serves a private "fritz.box" zone, in the + * non-existing TLD "box". Requests for the "fritz.box" domain + * are served by the router itself, while requests for the + * "box" domain will result in NXDOMAIN. + * + * Note that this logic is unable to detect cases where a + * router serves a private DNS zone directly under + * non-existing TLD. In such a case we cannot detect whether + * the TLD is supposed to exist or not, as all requests we + * make for it will be answered by the router's zone, and not + * by the root zone. */ + + assert(t); + + if (t->scope->dnssec_mode != DNSSEC_ALLOW_DOWNGRADE) + return false; /* In strict DNSSEC mode what doesn't exist, doesn't exist */ + + tld = dns_resource_key_name(key); + r = dns_name_parent(&tld); + if (r < 0) + return r; + if (r == 0) + return false; /* Already the root domain */ + + if (!dns_name_is_single_label(tld)) + return false; + + SET_FOREACH(dt, t->dnssec_transactions, i) { + + if (dt->key->class != key->class) + continue; + + r = dns_name_equal(dns_resource_key_name(dt->key), tld); + if (r < 0) + return r; + if (r == 0) + continue; + + /* We found an auxiliary lookup we did for the TLD. If + * that returned with NXDOMAIN, we know the TLD didn't + * exist, and hence this might be a private zone. */ + + return dt->answer_rcode == DNS_RCODE_NXDOMAIN; + } + + return false; +} + +static int dns_transaction_requires_nsec(DnsTransaction *t) { + char key_str[DNS_RESOURCE_KEY_STRING_MAX]; + DnsTransaction *dt; + const char *name; + uint16_t type = 0; + Iterator i; + int r; + + assert(t); + + /* Checks if we need to insist on NSEC/NSEC3 RRs for proving + * this negative reply */ + + if (t->scope->dnssec_mode == DNSSEC_NO) + return false; + + if (dns_type_is_pseudo(t->key->type)) + return -EINVAL; + + r = dns_transaction_negative_trust_anchor_lookup(t, dns_resource_key_name(t->key)); + if (r < 0) + return r; + if (r > 0) + return false; + + r = dns_transaction_in_private_tld(t, t->key); + if (r < 0) + return r; + if (r > 0) { + /* The lookup is from a TLD that is proven not to + * exist, and we are in downgrade mode, hence ignore + * that fact that we didn't get any NSEC RRs.*/ + + log_info("Detected a negative query %s in a private DNS zone, permitting unsigned response.", + dns_resource_key_to_string(t->key, key_str, sizeof key_str)); + return false; + } + + name = dns_resource_key_name(t->key); + + if (t->key->type == DNS_TYPE_DS) { + + /* We got a negative reply for this DS lookup? DS RRs are signed when their parent zone is signed, + * hence check the parent SOA in this case. */ + + r = dns_name_parent(&name); + if (r < 0) + return r; + if (r == 0) + return true; + + type = DNS_TYPE_SOA; + + } else if (IN_SET(t->key->type, DNS_TYPE_SOA, DNS_TYPE_NS)) + /* We got a negative reply for this SOA/NS lookup? If so, check if there's a DS RR for this */ + type = DNS_TYPE_DS; + else + /* For all other negative replies, check for the SOA lookup */ + type = DNS_TYPE_SOA; + + /* For all other RRs we check the SOA on the same level to see + * if it's signed. */ + + SET_FOREACH(dt, t->dnssec_transactions, i) { + + if (dt->key->class != t->key->class) + continue; + if (dt->key->type != type) + continue; + + r = dns_name_equal(dns_resource_key_name(dt->key), name); + if (r < 0) + return r; + if (r == 0) + continue; + + return dt->answer_authenticated; + } + + /* If in doubt, require NSEC/NSEC3 */ + return true; +} + +static int dns_transaction_dnskey_authenticated(DnsTransaction *t, DnsResourceRecord *rr) { + DnsResourceRecord *rrsig; + bool found = false; + int r; + + /* Checks whether any of the DNSKEYs used for the RRSIGs for + * the specified RRset is authenticated (i.e. has a matching + * DS RR). */ + + r = dns_transaction_negative_trust_anchor_lookup(t, dns_resource_key_name(rr->key)); + if (r < 0) + return r; + if (r > 0) + return false; + + DNS_ANSWER_FOREACH(rrsig, t->answer) { + DnsTransaction *dt; + Iterator i; + + r = dnssec_key_match_rrsig(rr->key, rrsig); + if (r < 0) + return r; + if (r == 0) + continue; + + SET_FOREACH(dt, t->dnssec_transactions, i) { + + if (dt->key->class != rr->key->class) + continue; + + if (dt->key->type == DNS_TYPE_DNSKEY) { + + r = dns_name_equal(dns_resource_key_name(dt->key), rrsig->rrsig.signer); + if (r < 0) + return r; + if (r == 0) + continue; + + /* OK, we found an auxiliary DNSKEY + * lookup. If that lookup is + * authenticated, report this. */ + + if (dt->answer_authenticated) + return true; + + found = true; + + } else if (dt->key->type == DNS_TYPE_DS) { + + r = dns_name_equal(dns_resource_key_name(dt->key), rrsig->rrsig.signer); + if (r < 0) + return r; + if (r == 0) + continue; + + /* OK, we found an auxiliary DS + * lookup. If that lookup is + * authenticated and non-zero, we + * won! */ + + if (!dt->answer_authenticated) + return false; + + return dns_answer_match_key(dt->answer, dt->key, NULL); + } + } + } + + return found ? false : -ENXIO; +} + +static int dns_transaction_known_signed(DnsTransaction *t, DnsResourceRecord *rr) { + assert(t); + assert(rr); + + /* We know that the root domain is signed, hence if it appears + * not to be signed, there's a problem with the DNS server */ + + return rr->key->class == DNS_CLASS_IN && + dns_name_is_root(dns_resource_key_name(rr->key)); +} + +static int dns_transaction_check_revoked_trust_anchors(DnsTransaction *t) { + DnsResourceRecord *rr; + int r; + + assert(t); + + /* Maybe warn the user that we encountered a revoked DNSKEY + * for a key from our trust anchor. Note that we don't care + * whether the DNSKEY can be authenticated or not. It's + * sufficient if it is self-signed. */ + + DNS_ANSWER_FOREACH(rr, t->answer) { + r = dns_trust_anchor_check_revoked(&t->scope->manager->trust_anchor, rr, t->answer); + if (r < 0) + return r; + } + + return 0; +} + +static int dns_transaction_invalidate_revoked_keys(DnsTransaction *t) { + bool changed; + int r; + + assert(t); + + /* Removes all DNSKEY/DS objects from t->validated_keys that + * our trust anchors database considers revoked. */ + + do { + DnsResourceRecord *rr; + + changed = false; + + DNS_ANSWER_FOREACH(rr, t->validated_keys) { + r = dns_trust_anchor_is_revoked(&t->scope->manager->trust_anchor, rr); + if (r < 0) + return r; + if (r > 0) { + r = dns_answer_remove_by_rr(&t->validated_keys, rr); + if (r < 0) + return r; + + assert(r > 0); + changed = true; + break; + } + } + } while (changed); + + return 0; +} + +static int dns_transaction_copy_validated(DnsTransaction *t) { + DnsTransaction *dt; + Iterator i; + int r; + + assert(t); + + /* Copy all validated RRs from the auxiliary DNSSEC transactions into our set of validated RRs */ + + SET_FOREACH(dt, t->dnssec_transactions, i) { + + if (DNS_TRANSACTION_IS_LIVE(dt->state)) + continue; + + if (!dt->answer_authenticated) + continue; + + r = dns_answer_extend(&t->validated_keys, dt->answer); + if (r < 0) + return r; + } + + return 0; +} + +typedef enum { + DNSSEC_PHASE_DNSKEY, /* Phase #1, only validate DNSKEYs */ + DNSSEC_PHASE_NSEC, /* Phase #2, only validate NSEC+NSEC3 */ + DNSSEC_PHASE_ALL, /* Phase #3, validate everything else */ +} Phase; + +static int dnssec_validate_records( + DnsTransaction *t, + Phase phase, + bool *have_nsec, + DnsAnswer **validated) { + + DnsResourceRecord *rr; + int r; + + /* Returns negative on error, 0 if validation failed, 1 to restart validation, 2 when finished. */ + + DNS_ANSWER_FOREACH(rr, t->answer) { + DnsResourceRecord *rrsig = NULL; + DnssecResult result; + + switch (rr->key->type) { + case DNS_TYPE_RRSIG: + continue; + + case DNS_TYPE_DNSKEY: + /* We validate DNSKEYs only in the DNSKEY and ALL phases */ + if (phase == DNSSEC_PHASE_NSEC) + continue; + break; + + case DNS_TYPE_NSEC: + case DNS_TYPE_NSEC3: + *have_nsec = true; + + /* We validate NSEC/NSEC3 only in the NSEC and ALL phases */ + if (phase == DNSSEC_PHASE_DNSKEY) + continue; + break; + + default: + /* We validate all other RRs only in the ALL phases */ + if (phase != DNSSEC_PHASE_ALL) + continue; + } + + r = dnssec_verify_rrset_search(t->answer, rr->key, t->validated_keys, USEC_INFINITY, &result, &rrsig); + if (r < 0) + return r; + + log_debug("Looking at %s: %s", strna(dns_resource_record_to_string(rr)), dnssec_result_to_string(result)); + + if (result == DNSSEC_VALIDATED) { + + if (rr->key->type == DNS_TYPE_DNSKEY) { + /* If we just validated a DNSKEY RRset, then let's add these keys to + * the set of validated keys for this transaction. */ + + r = dns_answer_copy_by_key(&t->validated_keys, t->answer, rr->key, DNS_ANSWER_AUTHENTICATED); + if (r < 0) + return r; + + /* Some of the DNSKEYs we just added might already have been revoked, + * remove them again in that case. */ + r = dns_transaction_invalidate_revoked_keys(t); + if (r < 0) + return r; + } + + /* Add the validated RRset to the new list of validated + * RRsets, and remove it from the unvalidated RRsets. + * We mark the RRset as authenticated and cacheable. */ + r = dns_answer_move_by_key(validated, &t->answer, rr->key, DNS_ANSWER_AUTHENTICATED|DNS_ANSWER_CACHEABLE); + if (r < 0) + return r; + + manager_dnssec_verdict(t->scope->manager, DNSSEC_SECURE, rr->key); + + /* Exit the loop, we dropped something from the answer, start from the beginning */ + return 1; + } + + /* If we haven't read all DNSKEYs yet a negative result of the validation is irrelevant, as + * there might be more DNSKEYs coming. Similar, if we haven't read all NSEC/NSEC3 RRs yet, + * we cannot do positive wildcard proofs yet, as those require the NSEC/NSEC3 RRs. */ + if (phase != DNSSEC_PHASE_ALL) + continue; + + if (result == DNSSEC_VALIDATED_WILDCARD) { + bool authenticated = false; + const char *source; + + /* This RRset validated, but as a wildcard. This means we need + * to prove via NSEC/NSEC3 that no matching non-wildcard RR exists.*/ + + /* First step, determine the source of synthesis */ + r = dns_resource_record_source(rrsig, &source); + if (r < 0) + return r; + + r = dnssec_test_positive_wildcard(*validated, + dns_resource_key_name(rr->key), + source, + rrsig->rrsig.signer, + &authenticated); + + /* Unless the NSEC proof showed that the key really doesn't exist something is off. */ + if (r == 0) + result = DNSSEC_INVALID; + else { + r = dns_answer_move_by_key(validated, &t->answer, rr->key, + authenticated ? (DNS_ANSWER_AUTHENTICATED|DNS_ANSWER_CACHEABLE) : 0); + if (r < 0) + return r; + + manager_dnssec_verdict(t->scope->manager, authenticated ? DNSSEC_SECURE : DNSSEC_INSECURE, rr->key); + + /* Exit the loop, we dropped something from the answer, start from the beginning */ + return 1; + } + } + + if (result == DNSSEC_NO_SIGNATURE) { + r = dns_transaction_requires_rrsig(t, rr); + if (r < 0) + return r; + if (r == 0) { + /* Data does not require signing. In that case, just copy it over, + * but remember that this is by no means authenticated.*/ + r = dns_answer_move_by_key(validated, &t->answer, rr->key, 0); + if (r < 0) + return r; + + manager_dnssec_verdict(t->scope->manager, DNSSEC_INSECURE, rr->key); + return 1; + } + + r = dns_transaction_known_signed(t, rr); + if (r < 0) + return r; + if (r > 0) { + /* This is an RR we know has to be signed. If it isn't this means + * the server is not attaching RRSIGs, hence complain. */ + + dns_server_packet_rrsig_missing(t->server, t->current_feature_level); + + if (t->scope->dnssec_mode == DNSSEC_ALLOW_DOWNGRADE) { + + /* Downgrading is OK? If so, just consider the information unsigned */ + + r = dns_answer_move_by_key(validated, &t->answer, rr->key, 0); + if (r < 0) + return r; + + manager_dnssec_verdict(t->scope->manager, DNSSEC_INSECURE, rr->key); + return 1; + } + + /* Otherwise, fail */ + t->answer_dnssec_result = DNSSEC_INCOMPATIBLE_SERVER; + return 0; + } + + r = dns_transaction_in_private_tld(t, rr->key); + if (r < 0) + return r; + if (r > 0) { + char s[DNS_RESOURCE_KEY_STRING_MAX]; + + /* The data is from a TLD that is proven not to exist, and we are in downgrade + * mode, hence ignore the fact that this was not signed. */ + + log_info("Detected RRset %s is in a private DNS zone, permitting unsigned RRs.", + dns_resource_key_to_string(rr->key, s, sizeof s)); + + r = dns_answer_move_by_key(validated, &t->answer, rr->key, 0); + if (r < 0) + return r; + + manager_dnssec_verdict(t->scope->manager, DNSSEC_INSECURE, rr->key); + return 1; + } + } + + if (IN_SET(result, + DNSSEC_MISSING_KEY, + DNSSEC_SIGNATURE_EXPIRED, + DNSSEC_UNSUPPORTED_ALGORITHM)) { + + r = dns_transaction_dnskey_authenticated(t, rr); + if (r < 0 && r != -ENXIO) + return r; + if (r == 0) { + /* The DNSKEY transaction was not authenticated, this means there's + * no DS for this, which means it's OK if no keys are found for this signature. */ + + r = dns_answer_move_by_key(validated, &t->answer, rr->key, 0); + if (r < 0) + return r; + + manager_dnssec_verdict(t->scope->manager, DNSSEC_INSECURE, rr->key); + return 1; + } + } + + r = dns_transaction_is_primary_response(t, rr); + if (r < 0) + return r; + if (r > 0) { + /* Look for a matching DNAME for this CNAME */ + r = dns_answer_has_dname_for_cname(t->answer, rr); + if (r < 0) + return r; + if (r == 0) { + /* Also look among the stuff we already validated */ + r = dns_answer_has_dname_for_cname(*validated, rr); + if (r < 0) + return r; + } + + if (r == 0) { + if (IN_SET(result, + DNSSEC_INVALID, + DNSSEC_SIGNATURE_EXPIRED, + DNSSEC_NO_SIGNATURE)) + manager_dnssec_verdict(t->scope->manager, DNSSEC_BOGUS, rr->key); + else /* DNSSEC_MISSING_KEY or DNSSEC_UNSUPPORTED_ALGORITHM */ + manager_dnssec_verdict(t->scope->manager, DNSSEC_INDETERMINATE, rr->key); + + /* This is a primary response to our question, and it failed validation. + * That's fatal. */ + t->answer_dnssec_result = result; + return 0; + } + + /* This is a primary response, but we do have a DNAME RR + * in the RR that can replay this CNAME, hence rely on + * that, and we can remove the CNAME in favour of it. */ + } + + /* This is just some auxiliary data. Just remove the RRset and continue. */ + r = dns_answer_remove_by_key(&t->answer, rr->key); + if (r < 0) + return r; + + /* We dropped something from the answer, start from the beginning. */ + return 1; + } + + return 2; /* Finito. */ +} + +int dns_transaction_validate_dnssec(DnsTransaction *t) { + _cleanup_(dns_answer_unrefp) DnsAnswer *validated = NULL; + Phase phase; + DnsAnswerFlags flags; + int r; + char key_str[DNS_RESOURCE_KEY_STRING_MAX]; + + assert(t); + + /* We have now collected all DS and DNSKEY RRs in + * t->validated_keys, let's see which RRs we can now + * authenticate with that. */ + + if (t->scope->dnssec_mode == DNSSEC_NO) + return 0; + + /* Already validated */ + if (t->answer_dnssec_result != _DNSSEC_RESULT_INVALID) + return 0; + + /* Our own stuff needs no validation */ + if (IN_SET(t->answer_source, DNS_TRANSACTION_ZONE, DNS_TRANSACTION_TRUST_ANCHOR)) { + t->answer_dnssec_result = DNSSEC_VALIDATED; + t->answer_authenticated = true; + return 0; + } + + /* Cached stuff is not affected by validation. */ + if (t->answer_source != DNS_TRANSACTION_NETWORK) + return 0; + + if (!dns_transaction_dnssec_supported_full(t)) { + /* The server does not support DNSSEC, or doesn't augment responses with RRSIGs. */ + t->answer_dnssec_result = DNSSEC_INCOMPATIBLE_SERVER; + log_debug("Not validating response for %" PRIu16 ", used server feature level does not support DNSSEC.", t->id); + return 0; + } + + log_debug("Validating response from transaction %" PRIu16 " (%s).", + t->id, + dns_resource_key_to_string(t->key, key_str, sizeof key_str)); + + /* First, see if this response contains any revoked trust + * anchors we care about */ + r = dns_transaction_check_revoked_trust_anchors(t); + if (r < 0) + return r; + + /* Third, copy all RRs we acquired successfully from auxiliary RRs over. */ + r = dns_transaction_copy_validated(t); + if (r < 0) + return r; + + /* Second, see if there are DNSKEYs we already know a + * validated DS for. */ + r = dns_transaction_validate_dnskey_by_ds(t); + if (r < 0) + return r; + + /* Fourth, remove all DNSKEY and DS RRs again that our trust + * anchor says are revoked. After all we might have marked + * some keys revoked above, but they might still be lingering + * in our validated_keys list. */ + r = dns_transaction_invalidate_revoked_keys(t); + if (r < 0) + return r; + + phase = DNSSEC_PHASE_DNSKEY; + for (;;) { + bool have_nsec = false; + + r = dnssec_validate_records(t, phase, &have_nsec, &validated); + if (r <= 0) + return r; + + /* Try again as long as we managed to achieve something */ + if (r == 1) + continue; + + if (phase == DNSSEC_PHASE_DNSKEY && have_nsec) { + /* OK, we processed all DNSKEYs, and there are NSEC/NSEC3 RRs, look at those now. */ + phase = DNSSEC_PHASE_NSEC; + continue; + } + + if (phase != DNSSEC_PHASE_ALL) { + /* OK, we processed all DNSKEYs and NSEC/NSEC3 RRs, look at all the rest now. + * Note that in this third phase we start to remove RRs we couldn't validate. */ + phase = DNSSEC_PHASE_ALL; + continue; + } + + /* We're done */ + break; + } + + dns_answer_unref(t->answer); + t->answer = validated; + validated = NULL; + + /* At this point the answer only contains validated + * RRsets. Now, let's see if it actually answers the question + * we asked. If so, great! If it doesn't, then see if + * NSEC/NSEC3 can prove this. */ + r = dns_transaction_has_positive_answer(t, &flags); + if (r > 0) { + /* Yes, it answers the question! */ + + if (flags & DNS_ANSWER_AUTHENTICATED) { + /* The answer is fully authenticated, yay. */ + t->answer_dnssec_result = DNSSEC_VALIDATED; + t->answer_rcode = DNS_RCODE_SUCCESS; + t->answer_authenticated = true; + } else { + /* The answer is not fully authenticated. */ + t->answer_dnssec_result = DNSSEC_UNSIGNED; + t->answer_authenticated = false; + } + + } else if (r == 0) { + DnssecNsecResult nr; + bool authenticated = false; + + /* Bummer! Let's check NSEC/NSEC3 */ + r = dnssec_nsec_test(t->answer, t->key, &nr, &authenticated, &t->answer_nsec_ttl); + if (r < 0) + return r; + + switch (nr) { + + case DNSSEC_NSEC_NXDOMAIN: + /* NSEC proves the domain doesn't exist. Very good. */ + log_debug("Proved NXDOMAIN via NSEC/NSEC3 for transaction %u (%s)", t->id, key_str); + t->answer_dnssec_result = DNSSEC_VALIDATED; + t->answer_rcode = DNS_RCODE_NXDOMAIN; + t->answer_authenticated = authenticated; + + manager_dnssec_verdict(t->scope->manager, authenticated ? DNSSEC_SECURE : DNSSEC_INSECURE, t->key); + break; + + case DNSSEC_NSEC_NODATA: + /* NSEC proves that there's no data here, very good. */ + log_debug("Proved NODATA via NSEC/NSEC3 for transaction %u (%s)", t->id, key_str); + t->answer_dnssec_result = DNSSEC_VALIDATED; + t->answer_rcode = DNS_RCODE_SUCCESS; + t->answer_authenticated = authenticated; + + manager_dnssec_verdict(t->scope->manager, authenticated ? DNSSEC_SECURE : DNSSEC_INSECURE, t->key); + break; + + case DNSSEC_NSEC_OPTOUT: + /* NSEC3 says the data might not be signed */ + log_debug("Data is NSEC3 opt-out via NSEC/NSEC3 for transaction %u (%s)", t->id, key_str); + t->answer_dnssec_result = DNSSEC_UNSIGNED; + t->answer_authenticated = false; + + manager_dnssec_verdict(t->scope->manager, DNSSEC_INSECURE, t->key); + break; + + case DNSSEC_NSEC_NO_RR: + /* No NSEC data? Bummer! */ + + r = dns_transaction_requires_nsec(t); + if (r < 0) + return r; + if (r > 0) { + t->answer_dnssec_result = DNSSEC_NO_SIGNATURE; + manager_dnssec_verdict(t->scope->manager, DNSSEC_BOGUS, t->key); + } else { + t->answer_dnssec_result = DNSSEC_UNSIGNED; + t->answer_authenticated = false; + manager_dnssec_verdict(t->scope->manager, DNSSEC_INSECURE, t->key); + } + + break; + + case DNSSEC_NSEC_UNSUPPORTED_ALGORITHM: + /* We don't know the NSEC3 algorithm used? */ + t->answer_dnssec_result = DNSSEC_UNSUPPORTED_ALGORITHM; + manager_dnssec_verdict(t->scope->manager, DNSSEC_INDETERMINATE, t->key); + break; + + case DNSSEC_NSEC_FOUND: + case DNSSEC_NSEC_CNAME: + /* NSEC says it needs to be there, but we couldn't find it? Bummer! */ + t->answer_dnssec_result = DNSSEC_NSEC_MISMATCH; + manager_dnssec_verdict(t->scope->manager, DNSSEC_BOGUS, t->key); + break; + + default: + assert_not_reached("Unexpected NSEC result."); + } + } + + return 1; +} + +static const char* const dns_transaction_state_table[_DNS_TRANSACTION_STATE_MAX] = { + [DNS_TRANSACTION_NULL] = "null", + [DNS_TRANSACTION_PENDING] = "pending", + [DNS_TRANSACTION_VALIDATING] = "validating", + [DNS_TRANSACTION_RCODE_FAILURE] = "rcode-failure", + [DNS_TRANSACTION_SUCCESS] = "success", + [DNS_TRANSACTION_NO_SERVERS] = "no-servers", + [DNS_TRANSACTION_TIMEOUT] = "timeout", + [DNS_TRANSACTION_ATTEMPTS_MAX_REACHED] = "attempts-max-reached", + [DNS_TRANSACTION_INVALID_REPLY] = "invalid-reply", + [DNS_TRANSACTION_ERRNO] = "errno", + [DNS_TRANSACTION_ABORTED] = "aborted", + [DNS_TRANSACTION_DNSSEC_FAILED] = "dnssec-failed", + [DNS_TRANSACTION_NO_TRUST_ANCHOR] = "no-trust-anchor", + [DNS_TRANSACTION_RR_TYPE_UNSUPPORTED] = "rr-type-unsupported", + [DNS_TRANSACTION_NETWORK_DOWN] = "network-down", + [DNS_TRANSACTION_NOT_FOUND] = "not-found", +}; +DEFINE_STRING_TABLE_LOOKUP(dns_transaction_state, DnsTransactionState); + +static const char* const dns_transaction_source_table[_DNS_TRANSACTION_SOURCE_MAX] = { + [DNS_TRANSACTION_NETWORK] = "network", + [DNS_TRANSACTION_CACHE] = "cache", + [DNS_TRANSACTION_ZONE] = "zone", + [DNS_TRANSACTION_TRUST_ANCHOR] = "trust-anchor", +}; +DEFINE_STRING_TABLE_LOOKUP(dns_transaction_source, DnsTransactionSource); diff --git a/src/grp-resolve/systemd-resolved/resolved-dns-transaction.h b/src/grp-resolve/systemd-resolved/resolved-dns-transaction.h new file mode 100644 index 0000000000..705336221d --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-dns-transaction.h @@ -0,0 +1,182 @@ +#pragma once + +/*** + This file is part of systemd. + + Copyright 2014 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +typedef struct DnsTransaction DnsTransaction; +typedef enum DnsTransactionState DnsTransactionState; +typedef enum DnsTransactionSource DnsTransactionSource; + +enum DnsTransactionState { + DNS_TRANSACTION_NULL, + DNS_TRANSACTION_PENDING, + DNS_TRANSACTION_VALIDATING, + DNS_TRANSACTION_RCODE_FAILURE, + DNS_TRANSACTION_SUCCESS, + DNS_TRANSACTION_NO_SERVERS, + DNS_TRANSACTION_TIMEOUT, + DNS_TRANSACTION_ATTEMPTS_MAX_REACHED, + DNS_TRANSACTION_INVALID_REPLY, + DNS_TRANSACTION_ERRNO, + DNS_TRANSACTION_ABORTED, + DNS_TRANSACTION_DNSSEC_FAILED, + DNS_TRANSACTION_NO_TRUST_ANCHOR, + DNS_TRANSACTION_RR_TYPE_UNSUPPORTED, + DNS_TRANSACTION_NETWORK_DOWN, + DNS_TRANSACTION_NOT_FOUND, /* like NXDOMAIN, but when LLMNR/TCP connections fail */ + _DNS_TRANSACTION_STATE_MAX, + _DNS_TRANSACTION_STATE_INVALID = -1 +}; + +#define DNS_TRANSACTION_IS_LIVE(state) IN_SET((state), DNS_TRANSACTION_NULL, DNS_TRANSACTION_PENDING, DNS_TRANSACTION_VALIDATING) + +enum DnsTransactionSource { + DNS_TRANSACTION_NETWORK, + DNS_TRANSACTION_CACHE, + DNS_TRANSACTION_ZONE, + DNS_TRANSACTION_TRUST_ANCHOR, + _DNS_TRANSACTION_SOURCE_MAX, + _DNS_TRANSACTION_SOURCE_INVALID = -1 +}; + +#include "basic-dns/resolved-dns-answer.h" +#include "basic-dns/resolved-dns-packet.h" +#include "basic-dns/resolved-dns-question.h" + +#include "resolved-dns-scope.h" +#include "resolved-dns-server.h" +#include "resolved-dns-stream.h" + +struct DnsTransaction { + DnsScope *scope; + + DnsResourceKey *key; + + DnsTransactionState state; + + uint16_t id; + + bool tried_stream:1; + + bool initial_jitter_scheduled:1; + bool initial_jitter_elapsed:1; + + bool clamp_ttl:1; + + DnsPacket *sent, *received; + + DnsAnswer *answer; + int answer_rcode; + DnssecResult answer_dnssec_result; + DnsTransactionSource answer_source; + uint32_t answer_nsec_ttl; + int answer_errno; /* if state is DNS_TRANSACTION_ERRNO */ + + /* Indicates whether the primary answer is authenticated, + * i.e. whether the RRs from answer which directly match the + * question are authenticated, or, if there are none, whether + * the NODATA or NXDOMAIN case is. It says nothing about + * additional RRs listed in the answer, however they have + * their own DNS_ANSWER_AUTHORIZED FLAGS. Note that this bit + * is defined different than the AD bit in DNS packets, as + * that covers more than just the actual primary answer. */ + bool answer_authenticated; + + /* Contains DNSKEY, DS, SOA RRs we already verified and need + * to authenticate this reply */ + DnsAnswer *validated_keys; + + usec_t start_usec; + usec_t next_attempt_after; + sd_event_source *timeout_event_source; + unsigned n_attempts; + + /* UDP connection logic, if we need it */ + int dns_udp_fd; + sd_event_source *dns_udp_event_source; + + /* TCP connection logic, if we need it */ + DnsStream *stream; + + /* The active server */ + DnsServer *server; + + /* The features of the DNS server at time of transaction start */ + DnsServerFeatureLevel current_feature_level; + + /* If we got SERVFAIL back, we retry the lookup, using a lower feature level than we used before. */ + DnsServerFeatureLevel clamp_feature_level; + + /* Query candidates this transaction is referenced by and that + * shall be notified about this specific transaction + * completing. */ + Set *notify_query_candidates, *notify_query_candidates_done; + + /* Zone items this transaction is referenced by and that shall + * be notified about completion. */ + Set *notify_zone_items, *notify_zone_items_done; + + /* Other transactions that this transactions is referenced by + * and that shall be notified about completion. This is used + * when transactions want to validate their RRsets, but need + * another DNSKEY or DS RR to do so. */ + Set *notify_transactions, *notify_transactions_done; + + /* The opposite direction: the transactions this transaction + * created in order to request DNSKEY or DS RRs. */ + Set *dnssec_transactions; + + unsigned block_gc; + + LIST_FIELDS(DnsTransaction, transactions_by_scope); +}; + +int dns_transaction_new(DnsTransaction **ret, DnsScope *s, DnsResourceKey *key); +DnsTransaction* dns_transaction_free(DnsTransaction *t); + +bool dns_transaction_gc(DnsTransaction *t); +int dns_transaction_go(DnsTransaction *t); + +void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p); +void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state); + +void dns_transaction_notify(DnsTransaction *t, DnsTransaction *source); +int dns_transaction_validate_dnssec(DnsTransaction *t); +int dns_transaction_request_dnssec_keys(DnsTransaction *t); + +const char* dns_transaction_state_to_string(DnsTransactionState p) _const_; +DnsTransactionState dns_transaction_state_from_string(const char *s) _pure_; + +const char* dns_transaction_source_to_string(DnsTransactionSource p) _const_; +DnsTransactionSource dns_transaction_source_from_string(const char *s) _pure_; + +/* LLMNR Jitter interval, see RFC 4795 Section 7 */ +#define LLMNR_JITTER_INTERVAL_USEC (100 * USEC_PER_MSEC) + +/* mDNS Jitter interval, see RFC 6762 Section 5.2 */ +#define MDNS_JITTER_MIN_USEC (20 * USEC_PER_MSEC) +#define MDNS_JITTER_RANGE_USEC (100 * USEC_PER_MSEC) + +/* Maximum attempts to send DNS requests, across all DNS servers */ +#define DNS_TRANSACTION_ATTEMPTS_MAX 16 + +/* Maximum attempts to send LLMNR requests, see RFC 4795 Section 2.7 */ +#define LLMNR_TRANSACTION_ATTEMPTS_MAX 3 + +#define TRANSACTION_ATTEMPTS_MAX(p) ((p) == DNS_PROTOCOL_LLMNR ? LLMNR_TRANSACTION_ATTEMPTS_MAX : DNS_TRANSACTION_ATTEMPTS_MAX) diff --git a/src/grp-resolve/systemd-resolved/resolved-dns-trust-anchor.c b/src/grp-resolve/systemd-resolved/resolved-dns-trust-anchor.c new file mode 100644 index 0000000000..cb45136788 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-dns-trust-anchor.c @@ -0,0 +1,747 @@ +/*** + This file is part of systemd. + + Copyright 2015 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include <systemd/sd-messages.h> + +#include "basic-dns/resolved-dns-dnssec.h" +#include "systemd-basic/alloc-util.h" +#include "systemd-basic/conf-files.h" +#include "systemd-basic/def.h" +#include "systemd-basic/fd-util.h" +#include "systemd-basic/fileio.h" +#include "systemd-basic/hexdecoct.h" +#include "systemd-basic/parse-util.h" +#include "systemd-basic/set.h" +#include "systemd-basic/string-util.h" +#include "systemd-basic/strv.h" +#include "systemd-shared/dns-domain.h" + +#include "resolved-dns-trust-anchor.h" + +static const char trust_anchor_dirs[] = CONF_PATHS_NULSTR("dnssec-trust-anchors.d"); + +/* The DS RR from https://data.iana.org/root-anchors/root-anchors.xml, retrieved December 2015 */ +static const uint8_t root_digest[] = + { 0x49, 0xAA, 0xC1, 0x1D, 0x7B, 0x6F, 0x64, 0x46, 0x70, 0x2E, 0x54, 0xA1, 0x60, 0x73, 0x71, 0x60, + 0x7A, 0x1A, 0x41, 0x85, 0x52, 0x00, 0xFD, 0x2C, 0xE1, 0xCD, 0xDE, 0x32, 0xF2, 0x4E, 0x8F, 0xB5 }; + +static bool dns_trust_anchor_knows_domain_positive(DnsTrustAnchor *d, const char *name) { + assert(d); + + /* Returns true if there's an entry for the specified domain + * name in our trust anchor */ + + return + hashmap_contains(d->positive_by_key, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN, DNS_TYPE_DNSKEY, name)) || + hashmap_contains(d->positive_by_key, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN, DNS_TYPE_DS, name)); +} + +static int dns_trust_anchor_add_builtin_positive(DnsTrustAnchor *d) { + _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL; + _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL; + int r; + + assert(d); + + r = hashmap_ensure_allocated(&d->positive_by_key, &dns_resource_key_hash_ops); + if (r < 0) + return r; + + /* Only add the built-in trust anchor if there's neither a DS + * nor a DNSKEY defined for the root domain. That way users + * have an easy way to override the root domain DS/DNSKEY + * data. */ + if (dns_trust_anchor_knows_domain_positive(d, ".")) + return 0; + + /* Add the RR from https://data.iana.org/root-anchors/root-anchors.xml */ + rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_DS, ""); + if (!rr) + return -ENOMEM; + + rr->ds.key_tag = 19036; + rr->ds.algorithm = DNSSEC_ALGORITHM_RSASHA256; + rr->ds.digest_type = DNSSEC_DIGEST_SHA256; + rr->ds.digest_size = sizeof(root_digest); + rr->ds.digest = memdup(root_digest, rr->ds.digest_size); + if (!rr->ds.digest) + return -ENOMEM; + + answer = dns_answer_new(1); + if (!answer) + return -ENOMEM; + + r = dns_answer_add(answer, rr, 0, DNS_ANSWER_AUTHENTICATED); + if (r < 0) + return r; + + r = hashmap_put(d->positive_by_key, rr->key, answer); + if (r < 0) + return r; + + answer = NULL; + return 0; +} + +static int dns_trust_anchor_add_builtin_negative(DnsTrustAnchor *d) { + + static const char private_domains[] = + /* RFC 6761 says that .test is a special domain for + * testing and not to be installed in the root zone */ + "test\0" + + /* RFC 6761 says that these reverse IP lookup ranges + * are for private addresses, and hence should not + * show up in the root zone */ + "10.in-addr.arpa\0" + "16.172.in-addr.arpa\0" + "17.172.in-addr.arpa\0" + "18.172.in-addr.arpa\0" + "19.172.in-addr.arpa\0" + "20.172.in-addr.arpa\0" + "21.172.in-addr.arpa\0" + "22.172.in-addr.arpa\0" + "23.172.in-addr.arpa\0" + "24.172.in-addr.arpa\0" + "25.172.in-addr.arpa\0" + "26.172.in-addr.arpa\0" + "27.172.in-addr.arpa\0" + "28.172.in-addr.arpa\0" + "29.172.in-addr.arpa\0" + "30.172.in-addr.arpa\0" + "31.172.in-addr.arpa\0" + "168.192.in-addr.arpa\0" + + /* The same, but for IPv6. */ + "d.f.ip6.arpa\0" + + /* RFC 6762 reserves the .local domain for Multicast + * DNS, it hence cannot appear in the root zone. (Note + * that we by default do not route .local traffic to + * DNS anyway, except when a configured search domain + * suggests so.) */ + "local\0" + + /* These two are well known, popular private zone + * TLDs, that are blocked from delegation, according + * to: + * http://icannwiki.com/Name_Collision#NGPC_Resolution + * + * There's also ongoing work on making this official + * in an RRC: + * https://www.ietf.org/archive/id/draft-chapin-additional-reserved-tlds-02.txt */ + "home\0" + "corp\0" + + /* The following four TLDs are suggested for private + * zones in RFC 6762, Appendix G, and are hence very + * unlikely to be made official TLDs any day soon */ + "lan\0" + "intranet\0" + "internal\0" + "private\0"; + + const char *name; + int r; + + assert(d); + + /* Only add the built-in trust anchor if there's no negative + * trust anchor defined at all. This enables easy overriding + * of negative trust anchors. */ + + if (set_size(d->negative_by_name) > 0) + return 0; + + r = set_ensure_allocated(&d->negative_by_name, &dns_name_hash_ops); + if (r < 0) + return r; + + /* We add a couple of domains as default negative trust + * anchors, where it's very unlikely they will be installed in + * the root zone. If they exist they must be private, and thus + * unsigned. */ + + NULSTR_FOREACH(name, private_domains) { + + if (dns_trust_anchor_knows_domain_positive(d, name)) + continue; + + r = set_put_strdup(d->negative_by_name, name); + if (r < 0) + return r; + } + + return 0; +} + +static int dns_trust_anchor_load_positive(DnsTrustAnchor *d, const char *path, unsigned line, const char *s) { + _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL; + _cleanup_free_ char *domain = NULL, *class = NULL, *type = NULL; + _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL; + DnsAnswer *old_answer = NULL; + const char *p = s; + int r; + + assert(d); + assert(line); + + r = extract_first_word(&p, &domain, NULL, EXTRACT_QUOTES); + if (r < 0) + return log_warning_errno(r, "Unable to parse domain in line %s:%u: %m", path, line); + + if (!dns_name_is_valid(domain)) { + log_warning("Domain name %s is invalid, at line %s:%u, ignoring line.", domain, path, line); + return -EINVAL; + } + + r = extract_many_words(&p, NULL, 0, &class, &type, NULL); + if (r < 0) + return log_warning_errno(r, "Unable to parse class and type in line %s:%u: %m", path, line); + if (r != 2) { + log_warning("Missing class or type in line %s:%u", path, line); + return -EINVAL; + } + + if (!strcaseeq(class, "IN")) { + log_warning("RR class %s is not supported, ignoring line %s:%u.", class, path, line); + return -EINVAL; + } + + if (strcaseeq(type, "DS")) { + _cleanup_free_ char *key_tag = NULL, *algorithm = NULL, *digest_type = NULL, *digest = NULL; + _cleanup_free_ void *dd = NULL; + uint16_t kt; + int a, dt; + size_t l; + + r = extract_many_words(&p, NULL, 0, &key_tag, &algorithm, &digest_type, &digest, NULL); + if (r < 0) { + log_warning_errno(r, "Failed to parse DS parameters on line %s:%u: %m", path, line); + return -EINVAL; + } + if (r != 4) { + log_warning("Missing DS parameters on line %s:%u", path, line); + return -EINVAL; + } + + r = safe_atou16(key_tag, &kt); + if (r < 0) + return log_warning_errno(r, "Failed to parse DS key tag %s on line %s:%u: %m", key_tag, path, line); + + a = dnssec_algorithm_from_string(algorithm); + if (a < 0) { + log_warning("Failed to parse DS algorithm %s on line %s:%u", algorithm, path, line); + return -EINVAL; + } + + dt = dnssec_digest_from_string(digest_type); + if (dt < 0) { + log_warning("Failed to parse DS digest type %s on line %s:%u", digest_type, path, line); + return -EINVAL; + } + + r = unhexmem(digest, strlen(digest), &dd, &l); + if (r < 0) { + log_warning("Failed to parse DS digest %s on line %s:%u", digest, path, line); + return -EINVAL; + } + + rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_DS, domain); + if (!rr) + return log_oom(); + + rr->ds.key_tag = kt; + rr->ds.algorithm = a; + rr->ds.digest_type = dt; + rr->ds.digest_size = l; + rr->ds.digest = dd; + dd = NULL; + + } else if (strcaseeq(type, "DNSKEY")) { + _cleanup_free_ char *flags = NULL, *protocol = NULL, *algorithm = NULL, *key = NULL; + _cleanup_free_ void *k = NULL; + uint16_t f; + size_t l; + int a; + + r = extract_many_words(&p, NULL, 0, &flags, &protocol, &algorithm, &key, NULL); + if (r < 0) + return log_warning_errno(r, "Failed to parse DNSKEY parameters on line %s:%u: %m", path, line); + if (r != 4) { + log_warning("Missing DNSKEY parameters on line %s:%u", path, line); + return -EINVAL; + } + + if (!streq(protocol, "3")) { + log_warning("DNSKEY Protocol is not 3 on line %s:%u", path, line); + return -EINVAL; + } + + r = safe_atou16(flags, &f); + if (r < 0) + return log_warning_errno(r, "Failed to parse DNSKEY flags field %s on line %s:%u", flags, path, line); + if ((f & DNSKEY_FLAG_ZONE_KEY) == 0) { + log_warning("DNSKEY lacks zone key bit set on line %s:%u", path, line); + return -EINVAL; + } + if ((f & DNSKEY_FLAG_REVOKE)) { + log_warning("DNSKEY is already revoked on line %s:%u", path, line); + return -EINVAL; + } + + a = dnssec_algorithm_from_string(algorithm); + if (a < 0) { + log_warning("Failed to parse DNSKEY algorithm %s on line %s:%u", algorithm, path, line); + return -EINVAL; + } + + r = unbase64mem(key, strlen(key), &k, &l); + if (r < 0) + return log_warning_errno(r, "Failed to parse DNSKEY key data %s on line %s:%u", key, path, line); + + rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_DNSKEY, domain); + if (!rr) + return log_oom(); + + rr->dnskey.flags = f; + rr->dnskey.protocol = 3; + rr->dnskey.algorithm = a; + rr->dnskey.key_size = l; + rr->dnskey.key = k; + k = NULL; + + } else { + log_warning("RR type %s is not supported, ignoring line %s:%u.", type, path, line); + return -EINVAL; + } + + if (!isempty(p)) { + log_warning("Trailing garbage on line %s:%u, ignoring line.", path, line); + return -EINVAL; + } + + r = hashmap_ensure_allocated(&d->positive_by_key, &dns_resource_key_hash_ops); + if (r < 0) + return log_oom(); + + old_answer = hashmap_get(d->positive_by_key, rr->key); + answer = dns_answer_ref(old_answer); + + r = dns_answer_add_extend(&answer, rr, 0, DNS_ANSWER_AUTHENTICATED); + if (r < 0) + return log_error_errno(r, "Failed to add trust anchor RR: %m"); + + r = hashmap_replace(d->positive_by_key, rr->key, answer); + if (r < 0) + return log_error_errno(r, "Failed to add answer to trust anchor: %m"); + + old_answer = dns_answer_unref(old_answer); + answer = NULL; + + return 0; +} + +static int dns_trust_anchor_load_negative(DnsTrustAnchor *d, const char *path, unsigned line, const char *s) { + _cleanup_free_ char *domain = NULL; + const char *p = s; + int r; + + assert(d); + assert(line); + + r = extract_first_word(&p, &domain, NULL, EXTRACT_QUOTES); + if (r < 0) + return log_warning_errno(r, "Unable to parse line %s:%u: %m", path, line); + + if (!dns_name_is_valid(domain)) { + log_warning("Domain name %s is invalid, at line %s:%u, ignoring line.", domain, path, line); + return -EINVAL; + } + + if (!isempty(p)) { + log_warning("Trailing garbage at line %s:%u, ignoring line.", path, line); + return -EINVAL; + } + + r = set_ensure_allocated(&d->negative_by_name, &dns_name_hash_ops); + if (r < 0) + return log_oom(); + + r = set_put(d->negative_by_name, domain); + if (r < 0) + return log_oom(); + if (r > 0) + domain = NULL; + + return 0; +} + +static int dns_trust_anchor_load_files( + DnsTrustAnchor *d, + const char *suffix, + int (*loader)(DnsTrustAnchor *d, const char *path, unsigned n, const char *line)) { + + _cleanup_strv_free_ char **files = NULL; + char **f; + int r; + + assert(d); + assert(suffix); + assert(loader); + + r = conf_files_list_nulstr(&files, suffix, NULL, trust_anchor_dirs); + if (r < 0) + return log_error_errno(r, "Failed to enumerate %s trust anchor files: %m", suffix); + + STRV_FOREACH(f, files) { + _cleanup_fclose_ FILE *g = NULL; + char line[LINE_MAX]; + unsigned n = 0; + + g = fopen(*f, "r"); + if (!g) { + if (errno == ENOENT) + continue; + + log_warning_errno(errno, "Failed to open %s: %m", *f); + continue; + } + + FOREACH_LINE(line, g, log_warning_errno(errno, "Failed to read %s, ignoring: %m", *f)) { + char *l; + + n++; + + l = strstrip(line); + if (isempty(l)) + continue; + + if (*l == ';') + continue; + + (void) loader(d, *f, n, l); + } + } + + return 0; +} + +static int domain_name_cmp(const void *a, const void *b) { + char **x = (char**) a, **y = (char**) b; + + return dns_name_compare_func(*x, *y); +} + +static int dns_trust_anchor_dump(DnsTrustAnchor *d) { + DnsAnswer *a; + Iterator i; + + assert(d); + + if (hashmap_isempty(d->positive_by_key)) + log_info("No positive trust anchors defined."); + else { + log_info("Positive Trust Anchors:"); + HASHMAP_FOREACH(a, d->positive_by_key, i) { + DnsResourceRecord *rr; + + DNS_ANSWER_FOREACH(rr, a) + log_info("%s", dns_resource_record_to_string(rr)); + } + } + + if (set_isempty(d->negative_by_name)) + log_info("No negative trust anchors defined."); + else { + _cleanup_free_ char **l = NULL, *j = NULL; + + l = set_get_strv(d->negative_by_name); + if (!l) + return log_oom(); + + qsort_safe(l, set_size(d->negative_by_name), sizeof(char*), domain_name_cmp); + + j = strv_join(l, " "); + if (!j) + return log_oom(); + + log_info("Negative trust anchors: %s", j); + } + + return 0; +} + +int dns_trust_anchor_load(DnsTrustAnchor *d) { + int r; + + assert(d); + + /* If loading things from disk fails, we don't consider this fatal */ + (void) dns_trust_anchor_load_files(d, ".positive", dns_trust_anchor_load_positive); + (void) dns_trust_anchor_load_files(d, ".negative", dns_trust_anchor_load_negative); + + /* However, if the built-in DS fails, then we have a problem. */ + r = dns_trust_anchor_add_builtin_positive(d); + if (r < 0) + return log_error_errno(r, "Failed to add built-in positive trust anchor: %m"); + + r = dns_trust_anchor_add_builtin_negative(d); + if (r < 0) + return log_error_errno(r, "Failed to add built-in negative trust anchor: %m"); + + dns_trust_anchor_dump(d); + + return 0; +} + +void dns_trust_anchor_flush(DnsTrustAnchor *d) { + DnsAnswer *a; + DnsResourceRecord *rr; + + assert(d); + + while ((a = hashmap_steal_first(d->positive_by_key))) + dns_answer_unref(a); + d->positive_by_key = hashmap_free(d->positive_by_key); + + while ((rr = set_steal_first(d->revoked_by_rr))) + dns_resource_record_unref(rr); + d->revoked_by_rr = set_free(d->revoked_by_rr); + + d->negative_by_name = set_free_free(d->negative_by_name); +} + +int dns_trust_anchor_lookup_positive(DnsTrustAnchor *d, const DnsResourceKey *key, DnsAnswer **ret) { + DnsAnswer *a; + + assert(d); + assert(key); + assert(ret); + + /* We only serve DS and DNSKEY RRs. */ + if (!IN_SET(key->type, DNS_TYPE_DS, DNS_TYPE_DNSKEY)) + return 0; + + a = hashmap_get(d->positive_by_key, key); + if (!a) + return 0; + + *ret = dns_answer_ref(a); + return 1; +} + +int dns_trust_anchor_lookup_negative(DnsTrustAnchor *d, const char *name) { + assert(d); + assert(name); + + return set_contains(d->negative_by_name, name); +} + +static int dns_trust_anchor_revoked_put(DnsTrustAnchor *d, DnsResourceRecord *rr) { + int r; + + assert(d); + + r = set_ensure_allocated(&d->revoked_by_rr, &dns_resource_record_hash_ops); + if (r < 0) + return r; + + r = set_put(d->revoked_by_rr, rr); + if (r < 0) + return r; + if (r > 0) + dns_resource_record_ref(rr); + + return r; +} + +static int dns_trust_anchor_remove_revoked(DnsTrustAnchor *d, DnsResourceRecord *rr) { + _cleanup_(dns_answer_unrefp) DnsAnswer *new_answer = NULL; + DnsAnswer *old_answer; + int r; + + /* Remember that this is a revoked trust anchor RR */ + r = dns_trust_anchor_revoked_put(d, rr); + if (r < 0) + return r; + + /* Remove this from the positive trust anchor */ + old_answer = hashmap_get(d->positive_by_key, rr->key); + if (!old_answer) + return 0; + + new_answer = dns_answer_ref(old_answer); + + r = dns_answer_remove_by_rr(&new_answer, rr); + if (r <= 0) + return r; + + /* We found the key! Warn the user */ + log_struct(LOG_WARNING, + LOG_MESSAGE_ID(SD_MESSAGE_DNSSEC_TRUST_ANCHOR_REVOKED), + LOG_MESSAGE("DNSSEC Trust anchor %s has been revoked. Please update the trust anchor, or upgrade your operating system."), strna(dns_resource_record_to_string(rr)), + "TRUST_ANCHOR=%s", dns_resource_record_to_string(rr), + NULL); + + if (dns_answer_size(new_answer) <= 0) { + assert_se(hashmap_remove(d->positive_by_key, rr->key) == old_answer); + dns_answer_unref(old_answer); + return 1; + } + + r = hashmap_replace(d->positive_by_key, new_answer->items[0].rr->key, new_answer); + if (r < 0) + return r; + + new_answer = NULL; + dns_answer_unref(old_answer); + return 1; +} + +static int dns_trust_anchor_check_revoked_one(DnsTrustAnchor *d, DnsResourceRecord *revoked_dnskey) { + DnsAnswer *a; + int r; + + assert(d); + assert(revoked_dnskey); + assert(revoked_dnskey->key->type == DNS_TYPE_DNSKEY); + assert(revoked_dnskey->dnskey.flags & DNSKEY_FLAG_REVOKE); + + a = hashmap_get(d->positive_by_key, revoked_dnskey->key); + if (a) { + DnsResourceRecord *anchor; + + /* First, look for the precise DNSKEY in our trust anchor database */ + + DNS_ANSWER_FOREACH(anchor, a) { + + if (anchor->dnskey.protocol != revoked_dnskey->dnskey.protocol) + continue; + + if (anchor->dnskey.algorithm != revoked_dnskey->dnskey.algorithm) + continue; + + if (anchor->dnskey.key_size != revoked_dnskey->dnskey.key_size) + continue; + + /* Note that we allow the REVOKE bit to be + * different! It will be set in the revoked + * key, but unset in our version of it */ + if (((anchor->dnskey.flags ^ revoked_dnskey->dnskey.flags) | DNSKEY_FLAG_REVOKE) != DNSKEY_FLAG_REVOKE) + continue; + + if (memcmp(anchor->dnskey.key, revoked_dnskey->dnskey.key, anchor->dnskey.key_size) != 0) + continue; + + dns_trust_anchor_remove_revoked(d, anchor); + break; + } + } + + a = hashmap_get(d->positive_by_key, &DNS_RESOURCE_KEY_CONST(revoked_dnskey->key->class, DNS_TYPE_DS, dns_resource_key_name(revoked_dnskey->key))); + if (a) { + DnsResourceRecord *anchor; + + /* Second, look for DS RRs matching this DNSKEY in our trust anchor database */ + + DNS_ANSWER_FOREACH(anchor, a) { + + /* We set mask_revoke to true here, since our + * DS fingerprint will be the one of the + * unrevoked DNSKEY, but the one we got passed + * here has the bit set. */ + r = dnssec_verify_dnskey_by_ds(revoked_dnskey, anchor, true); + if (r < 0) + return r; + if (r == 0) + continue; + + dns_trust_anchor_remove_revoked(d, anchor); + break; + } + } + + return 0; +} + +int dns_trust_anchor_check_revoked(DnsTrustAnchor *d, DnsResourceRecord *dnskey, DnsAnswer *rrs) { + DnsResourceRecord *rrsig; + int r; + + assert(d); + assert(dnskey); + + /* Looks if "dnskey" is a self-signed RR that has been revoked + * and matches one of our trust anchor entries. If so, removes + * it from the trust anchor and returns > 0. */ + + if (dnskey->key->type != DNS_TYPE_DNSKEY) + return 0; + + /* Is this DNSKEY revoked? */ + if ((dnskey->dnskey.flags & DNSKEY_FLAG_REVOKE) == 0) + return 0; + + /* Could this be interesting to us at all? If not, + * there's no point in looking for and verifying a + * self-signed RRSIG. */ + if (!dns_trust_anchor_knows_domain_positive(d, dns_resource_key_name(dnskey->key))) + return 0; + + /* Look for a self-signed RRSIG in the other rrs belonging to this DNSKEY */ + DNS_ANSWER_FOREACH(rrsig, rrs) { + DnssecResult result; + + if (rrsig->key->type != DNS_TYPE_RRSIG) + continue; + + r = dnssec_rrsig_match_dnskey(rrsig, dnskey, true); + if (r < 0) + return r; + if (r == 0) + continue; + + r = dnssec_verify_rrset(rrs, dnskey->key, rrsig, dnskey, USEC_INFINITY, &result); + if (r < 0) + return r; + if (result != DNSSEC_VALIDATED) + continue; + + /* Bingo! This is a revoked self-signed DNSKEY. Let's + * see if this precise one exists in our trust anchor + * database, too. */ + r = dns_trust_anchor_check_revoked_one(d, dnskey); + if (r < 0) + return r; + + return 1; + } + + return 0; +} + +int dns_trust_anchor_is_revoked(DnsTrustAnchor *d, DnsResourceRecord *rr) { + assert(d); + + if (!IN_SET(rr->key->type, DNS_TYPE_DS, DNS_TYPE_DNSKEY)) + return 0; + + return set_contains(d->revoked_by_rr, rr); +} diff --git a/src/grp-resolve/systemd-resolved/resolved-dns-trust-anchor.h b/src/grp-resolve/systemd-resolved/resolved-dns-trust-anchor.h new file mode 100644 index 0000000000..9039bd7aa3 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-dns-trust-anchor.h @@ -0,0 +1,43 @@ +#pragma once + +/*** + This file is part of systemd. + + Copyright 2015 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include "basic-dns/resolved-dns-answer.h" +#include "basic-dns/resolved-dns-rr.h" +#include "systemd-basic/hashmap.h" + +typedef struct DnsTrustAnchor DnsTrustAnchor; + +/* This contains a fixed database mapping domain names to DS or DNSKEY records. */ + +struct DnsTrustAnchor { + Hashmap *positive_by_key; + Set *negative_by_name; + Set *revoked_by_rr; +}; + +int dns_trust_anchor_load(DnsTrustAnchor *d); +void dns_trust_anchor_flush(DnsTrustAnchor *d); + +int dns_trust_anchor_lookup_positive(DnsTrustAnchor *d, const DnsResourceKey* key, DnsAnswer **answer); +int dns_trust_anchor_lookup_negative(DnsTrustAnchor *d, const char *name); + +int dns_trust_anchor_check_revoked(DnsTrustAnchor *d, DnsResourceRecord *dnskey, DnsAnswer *rrs); +int dns_trust_anchor_is_revoked(DnsTrustAnchor *d, DnsResourceRecord *rr); diff --git a/src/grp-resolve/systemd-resolved/resolved-dns-zone.c b/src/grp-resolve/systemd-resolved/resolved-dns-zone.c new file mode 100644 index 0000000000..723df26454 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-dns-zone.c @@ -0,0 +1,665 @@ +/*** + This file is part of systemd. + + Copyright 2014 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include "basic-dns/resolved-dns-packet.h" +#include "systemd-basic/alloc-util.h" +#include "systemd-basic/list.h" +#include "systemd-basic/string-util.h" +#include "systemd-shared/dns-domain.h" + +#include "resolved-dns-zone.h" + +/* Never allow more than 1K entries */ +#define ZONE_MAX 1024 + +void dns_zone_item_probe_stop(DnsZoneItem *i) { + DnsTransaction *t; + assert(i); + + if (!i->probe_transaction) + return; + + t = i->probe_transaction; + i->probe_transaction = NULL; + + set_remove(t->notify_zone_items, i); + set_remove(t->notify_zone_items_done, i); + dns_transaction_gc(t); +} + +static void dns_zone_item_free(DnsZoneItem *i) { + if (!i) + return; + + dns_zone_item_probe_stop(i); + dns_resource_record_unref(i->rr); + + free(i); +} + +DEFINE_TRIVIAL_CLEANUP_FUNC(DnsZoneItem*, dns_zone_item_free); + +static void dns_zone_item_remove_and_free(DnsZone *z, DnsZoneItem *i) { + DnsZoneItem *first; + + assert(z); + + if (!i) + return; + + first = hashmap_get(z->by_key, i->rr->key); + LIST_REMOVE(by_key, first, i); + if (first) + assert_se(hashmap_replace(z->by_key, first->rr->key, first) >= 0); + else + hashmap_remove(z->by_key, i->rr->key); + + first = hashmap_get(z->by_name, dns_resource_key_name(i->rr->key)); + LIST_REMOVE(by_name, first, i); + if (first) + assert_se(hashmap_replace(z->by_name, dns_resource_key_name(first->rr->key), first) >= 0); + else + hashmap_remove(z->by_name, dns_resource_key_name(i->rr->key)); + + dns_zone_item_free(i); +} + +void dns_zone_flush(DnsZone *z) { + DnsZoneItem *i; + + assert(z); + + while ((i = hashmap_first(z->by_key))) + dns_zone_item_remove_and_free(z, i); + + assert(hashmap_size(z->by_key) == 0); + assert(hashmap_size(z->by_name) == 0); + + z->by_key = hashmap_free(z->by_key); + z->by_name = hashmap_free(z->by_name); +} + +static DnsZoneItem* dns_zone_get(DnsZone *z, DnsResourceRecord *rr) { + DnsZoneItem *i; + + assert(z); + assert(rr); + + LIST_FOREACH(by_key, i, hashmap_get(z->by_key, rr->key)) + if (dns_resource_record_equal(i->rr, rr) > 0) + return i; + + return NULL; +} + +void dns_zone_remove_rr(DnsZone *z, DnsResourceRecord *rr) { + DnsZoneItem *i; + + assert(z); + assert(rr); + + i = dns_zone_get(z, rr); + if (i) + dns_zone_item_remove_and_free(z, i); +} + +static int dns_zone_init(DnsZone *z) { + int r; + + assert(z); + + r = hashmap_ensure_allocated(&z->by_key, &dns_resource_key_hash_ops); + if (r < 0) + return r; + + r = hashmap_ensure_allocated(&z->by_name, &dns_name_hash_ops); + if (r < 0) + return r; + + return 0; +} + +static int dns_zone_link_item(DnsZone *z, DnsZoneItem *i) { + DnsZoneItem *first; + int r; + + first = hashmap_get(z->by_key, i->rr->key); + if (first) { + LIST_PREPEND(by_key, first, i); + assert_se(hashmap_replace(z->by_key, first->rr->key, first) >= 0); + } else { + r = hashmap_put(z->by_key, i->rr->key, i); + if (r < 0) + return r; + } + + first = hashmap_get(z->by_name, dns_resource_key_name(i->rr->key)); + if (first) { + LIST_PREPEND(by_name, first, i); + assert_se(hashmap_replace(z->by_name, dns_resource_key_name(first->rr->key), first) >= 0); + } else { + r = hashmap_put(z->by_name, dns_resource_key_name(i->rr->key), i); + if (r < 0) + return r; + } + + return 0; +} + +static int dns_zone_item_probe_start(DnsZoneItem *i) { + DnsTransaction *t; + int r; + + assert(i); + + if (i->probe_transaction) + return 0; + + t = dns_scope_find_transaction(i->scope, &DNS_RESOURCE_KEY_CONST(i->rr->key->class, DNS_TYPE_ANY, dns_resource_key_name(i->rr->key)), false); + if (!t) { + _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL; + + key = dns_resource_key_new(i->rr->key->class, DNS_TYPE_ANY, dns_resource_key_name(i->rr->key)); + if (!key) + return -ENOMEM; + + r = dns_transaction_new(&t, i->scope, key); + if (r < 0) + return r; + } + + r = set_ensure_allocated(&t->notify_zone_items, NULL); + if (r < 0) + goto gc; + + r = set_ensure_allocated(&t->notify_zone_items_done, NULL); + if (r < 0) + goto gc; + + r = set_put(t->notify_zone_items, i); + if (r < 0) + goto gc; + + i->probe_transaction = t; + + if (t->state == DNS_TRANSACTION_NULL) { + + i->block_ready++; + r = dns_transaction_go(t); + i->block_ready--; + + if (r < 0) { + dns_zone_item_probe_stop(i); + return r; + } + } + + dns_zone_item_notify(i); + return 0; + +gc: + dns_transaction_gc(t); + return r; +} + +int dns_zone_put(DnsZone *z, DnsScope *s, DnsResourceRecord *rr, bool probe) { + _cleanup_(dns_zone_item_freep) DnsZoneItem *i = NULL; + DnsZoneItem *existing; + int r; + + assert(z); + assert(s); + assert(rr); + + if (dns_class_is_pseudo(rr->key->class)) + return -EINVAL; + if (dns_type_is_pseudo(rr->key->type)) + return -EINVAL; + + existing = dns_zone_get(z, rr); + if (existing) + return 0; + + r = dns_zone_init(z); + if (r < 0) + return r; + + i = new0(DnsZoneItem, 1); + if (!i) + return -ENOMEM; + + i->scope = s; + i->rr = dns_resource_record_ref(rr); + i->probing_enabled = probe; + + r = dns_zone_link_item(z, i); + if (r < 0) + return r; + + if (probe) { + DnsZoneItem *first, *j; + bool established = false; + + /* Check if there's already an RR with the same name + * established. If so, it has been probed already, and + * we don't ned to probe again. */ + + LIST_FIND_HEAD(by_name, i, first); + LIST_FOREACH(by_name, j, first) { + if (i == j) + continue; + + if (j->state == DNS_ZONE_ITEM_ESTABLISHED) + established = true; + } + + if (established) + i->state = DNS_ZONE_ITEM_ESTABLISHED; + else { + i->state = DNS_ZONE_ITEM_PROBING; + + r = dns_zone_item_probe_start(i); + if (r < 0) { + dns_zone_item_remove_and_free(z, i); + i = NULL; + return r; + } + } + } else + i->state = DNS_ZONE_ITEM_ESTABLISHED; + + i = NULL; + return 0; +} + +int dns_zone_lookup(DnsZone *z, DnsResourceKey *key, int ifindex, DnsAnswer **ret_answer, DnsAnswer **ret_soa, bool *ret_tentative) { + _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL, *soa = NULL; + unsigned n_answer = 0; + DnsZoneItem *j, *first; + bool tentative = true, need_soa = false; + int r; + + /* Note that we don't actually need the ifindex for anything. However when it is passed we'll initialize the + * ifindex field in the answer with it */ + + assert(z); + assert(key); + assert(ret_answer); + + /* First iteration, count what we have */ + + if (key->type == DNS_TYPE_ANY || key->class == DNS_CLASS_ANY) { + bool found = false, added = false; + int k; + + /* If this is a generic match, then we have to + * go through the list by the name and look + * for everything manually */ + + first = hashmap_get(z->by_name, dns_resource_key_name(key)); + LIST_FOREACH(by_name, j, first) { + if (!IN_SET(j->state, DNS_ZONE_ITEM_PROBING, DNS_ZONE_ITEM_ESTABLISHED, DNS_ZONE_ITEM_VERIFYING)) + continue; + + found = true; + + k = dns_resource_key_match_rr(key, j->rr, NULL); + if (k < 0) + return k; + if (k > 0) { + n_answer++; + added = true; + } + + } + + if (found && !added) + need_soa = true; + + } else { + bool found = false; + + /* If this is a specific match, then look for + * the right key immediately */ + + first = hashmap_get(z->by_key, key); + LIST_FOREACH(by_key, j, first) { + if (!IN_SET(j->state, DNS_ZONE_ITEM_PROBING, DNS_ZONE_ITEM_ESTABLISHED, DNS_ZONE_ITEM_VERIFYING)) + continue; + + found = true; + n_answer++; + } + + if (!found) { + first = hashmap_get(z->by_name, dns_resource_key_name(key)); + LIST_FOREACH(by_name, j, first) { + if (!IN_SET(j->state, DNS_ZONE_ITEM_PROBING, DNS_ZONE_ITEM_ESTABLISHED, DNS_ZONE_ITEM_VERIFYING)) + continue; + + need_soa = true; + break; + } + } + } + + if (n_answer <= 0 && !need_soa) + goto return_empty; + + if (n_answer > 0) { + answer = dns_answer_new(n_answer); + if (!answer) + return -ENOMEM; + } + + if (need_soa) { + soa = dns_answer_new(1); + if (!soa) + return -ENOMEM; + } + + /* Second iteration, actually add the RRs to the answers */ + if (key->type == DNS_TYPE_ANY || key->class == DNS_CLASS_ANY) { + bool found = false, added = false; + int k; + + first = hashmap_get(z->by_name, dns_resource_key_name(key)); + LIST_FOREACH(by_name, j, first) { + if (!IN_SET(j->state, DNS_ZONE_ITEM_PROBING, DNS_ZONE_ITEM_ESTABLISHED, DNS_ZONE_ITEM_VERIFYING)) + continue; + + found = true; + + if (j->state != DNS_ZONE_ITEM_PROBING) + tentative = false; + + k = dns_resource_key_match_rr(key, j->rr, NULL); + if (k < 0) + return k; + if (k > 0) { + r = dns_answer_add(answer, j->rr, ifindex, DNS_ANSWER_AUTHENTICATED); + if (r < 0) + return r; + + added = true; + } + } + + if (found && !added) { + r = dns_answer_add_soa(soa, dns_resource_key_name(key), LLMNR_DEFAULT_TTL, ifindex); + if (r < 0) + return r; + } + } else { + bool found = false; + + first = hashmap_get(z->by_key, key); + LIST_FOREACH(by_key, j, first) { + if (!IN_SET(j->state, DNS_ZONE_ITEM_PROBING, DNS_ZONE_ITEM_ESTABLISHED, DNS_ZONE_ITEM_VERIFYING)) + continue; + + found = true; + + if (j->state != DNS_ZONE_ITEM_PROBING) + tentative = false; + + r = dns_answer_add(answer, j->rr, ifindex, DNS_ANSWER_AUTHENTICATED); + if (r < 0) + return r; + } + + if (!found) { + bool add_soa = false; + + first = hashmap_get(z->by_name, dns_resource_key_name(key)); + LIST_FOREACH(by_name, j, first) { + if (!IN_SET(j->state, DNS_ZONE_ITEM_PROBING, DNS_ZONE_ITEM_ESTABLISHED, DNS_ZONE_ITEM_VERIFYING)) + continue; + + if (j->state != DNS_ZONE_ITEM_PROBING) + tentative = false; + + add_soa = true; + } + + if (add_soa) { + r = dns_answer_add_soa(soa, dns_resource_key_name(key), LLMNR_DEFAULT_TTL, ifindex); + if (r < 0) + return r; + } + } + } + + /* If the caller sets ret_tentative to NULL, then use this as + * indication to not return tentative entries */ + + if (!ret_tentative && tentative) + goto return_empty; + + *ret_answer = answer; + answer = NULL; + + if (ret_soa) { + *ret_soa = soa; + soa = NULL; + } + + if (ret_tentative) + *ret_tentative = tentative; + + return 1; + +return_empty: + *ret_answer = NULL; + + if (ret_soa) + *ret_soa = NULL; + + if (ret_tentative) + *ret_tentative = false; + + return 0; +} + +void dns_zone_item_conflict(DnsZoneItem *i) { + assert(i); + + if (!IN_SET(i->state, DNS_ZONE_ITEM_PROBING, DNS_ZONE_ITEM_VERIFYING, DNS_ZONE_ITEM_ESTABLISHED)) + return; + + log_info("Detected conflict on %s", strna(dns_resource_record_to_string(i->rr))); + + dns_zone_item_probe_stop(i); + + /* Withdraw the conflict item */ + i->state = DNS_ZONE_ITEM_WITHDRAWN; + + /* Maybe change the hostname */ + if (manager_is_own_hostname(i->scope->manager, dns_resource_key_name(i->rr->key)) > 0) + manager_next_hostname(i->scope->manager); +} + +void dns_zone_item_notify(DnsZoneItem *i) { + assert(i); + assert(i->probe_transaction); + + if (i->block_ready > 0) + return; + + if (IN_SET(i->probe_transaction->state, DNS_TRANSACTION_NULL, DNS_TRANSACTION_PENDING, DNS_TRANSACTION_VALIDATING)) + return; + + if (i->probe_transaction->state == DNS_TRANSACTION_SUCCESS) { + bool we_lost = false; + + /* The probe got a successful reply. If we so far + * weren't established we just give up. If we already + * were established, and the peer has the + * lexicographically larger IP address we continue + * and defend it. */ + + if (!IN_SET(i->state, DNS_ZONE_ITEM_ESTABLISHED, DNS_ZONE_ITEM_VERIFYING)) { + log_debug("Got a successful probe for not yet established RR, we lost."); + we_lost = true; + } else { + assert(i->probe_transaction->received); + we_lost = memcmp(&i->probe_transaction->received->sender, &i->probe_transaction->received->destination, FAMILY_ADDRESS_SIZE(i->probe_transaction->received->family)) < 0; + if (we_lost) + log_debug("Got a successful probe reply for an established RR, and we have a lexicographically larger IP address and thus lost."); + } + + if (we_lost) { + dns_zone_item_conflict(i); + return; + } + + log_debug("Got a successful probe reply, but peer has lexicographically lower IP address and thus lost."); + } + + log_debug("Record %s successfully probed.", strna(dns_resource_record_to_string(i->rr))); + + dns_zone_item_probe_stop(i); + i->state = DNS_ZONE_ITEM_ESTABLISHED; +} + +static int dns_zone_item_verify(DnsZoneItem *i) { + int r; + + assert(i); + + if (i->state != DNS_ZONE_ITEM_ESTABLISHED) + return 0; + + log_debug("Verifying RR %s", strna(dns_resource_record_to_string(i->rr))); + + i->state = DNS_ZONE_ITEM_VERIFYING; + r = dns_zone_item_probe_start(i); + if (r < 0) { + log_error_errno(r, "Failed to start probing for verifying RR: %m"); + i->state = DNS_ZONE_ITEM_ESTABLISHED; + return r; + } + + return 0; +} + +int dns_zone_check_conflicts(DnsZone *zone, DnsResourceRecord *rr) { + DnsZoneItem *i, *first; + int c = 0; + + assert(zone); + assert(rr); + + /* This checks whether a response RR we received from somebody + * else is one that we actually thought was uniquely ours. If + * so, we'll verify our RRs. */ + + /* No conflict if we don't have the name at all. */ + first = hashmap_get(zone->by_name, dns_resource_key_name(rr->key)); + if (!first) + return 0; + + /* No conflict if we have the exact same RR */ + if (dns_zone_get(zone, rr)) + return 0; + + /* OK, somebody else has RRs for the same name. Yuck! Let's + * start probing again */ + + LIST_FOREACH(by_name, i, first) { + if (dns_resource_record_equal(i->rr, rr)) + continue; + + dns_zone_item_verify(i); + c++; + } + + return c; +} + +int dns_zone_verify_conflicts(DnsZone *zone, DnsResourceKey *key) { + DnsZoneItem *i, *first; + int c = 0; + + assert(zone); + + /* Somebody else notified us about a possible conflict. Let's + * verify if that's true. */ + + first = hashmap_get(zone->by_name, dns_resource_key_name(key)); + if (!first) + return 0; + + LIST_FOREACH(by_name, i, first) { + dns_zone_item_verify(i); + c++; + } + + return c; +} + +void dns_zone_verify_all(DnsZone *zone) { + DnsZoneItem *i; + Iterator iterator; + + assert(zone); + + HASHMAP_FOREACH(i, zone->by_key, iterator) { + DnsZoneItem *j; + + LIST_FOREACH(by_key, j, i) + dns_zone_item_verify(j); + } +} + +void dns_zone_dump(DnsZone *zone, FILE *f) { + Iterator iterator; + DnsZoneItem *i; + + if (!zone) + return; + + if (!f) + f = stdout; + + HASHMAP_FOREACH(i, zone->by_key, iterator) { + DnsZoneItem *j; + + LIST_FOREACH(by_key, j, i) { + const char *t; + + t = dns_resource_record_to_string(j->rr); + if (!t) { + log_oom(); + continue; + } + + fputc('\t', f); + fputs(t, f); + fputc('\n', f); + } + } +} + +bool dns_zone_is_empty(DnsZone *zone) { + if (!zone) + return true; + + return hashmap_isempty(zone->by_key); +} diff --git a/src/grp-resolve/systemd-resolved/resolved-dns-zone.h b/src/grp-resolve/systemd-resolved/resolved-dns-zone.h new file mode 100644 index 0000000000..fe656be793 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-dns-zone.h @@ -0,0 +1,82 @@ +#pragma once + +/*** + This file is part of systemd. + + Copyright 2014 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include "systemd-basic/hashmap.h" + +typedef struct DnsZone { + Hashmap *by_key; + Hashmap *by_name; +} DnsZone; + +#include "basic-dns/resolved-dns-answer.h" +#include "basic-dns/resolved-dns-question.h" +#include "basic-dns/resolved-dns-rr.h" + +typedef enum DnsZoneItemState DnsZoneItemState; +typedef struct DnsZoneItem DnsZoneItem; + +#include "resolved-dns-transaction.h" + +/* RFC 4795 Section 2.8. suggests a TTL of 30s by default */ +#define LLMNR_DEFAULT_TTL (30) + +enum DnsZoneItemState { + DNS_ZONE_ITEM_PROBING, + DNS_ZONE_ITEM_ESTABLISHED, + DNS_ZONE_ITEM_VERIFYING, + DNS_ZONE_ITEM_WITHDRAWN, +}; + +struct DnsZoneItem { + DnsScope *scope; + DnsResourceRecord *rr; + + DnsZoneItemState state; + + unsigned block_ready; + + bool probing_enabled; + + LIST_FIELDS(DnsZoneItem, by_key); + LIST_FIELDS(DnsZoneItem, by_name); + + DnsTransaction *probe_transaction; +}; + +void dns_zone_flush(DnsZone *z); + +int dns_zone_put(DnsZone *z, DnsScope *s, DnsResourceRecord *rr, bool probe); +void dns_zone_remove_rr(DnsZone *z, DnsResourceRecord *rr); + +int dns_zone_lookup(DnsZone *z, DnsResourceKey *key, int ifindex, DnsAnswer **answer, DnsAnswer **soa, bool *tentative); + +void dns_zone_item_conflict(DnsZoneItem *i); +void dns_zone_item_notify(DnsZoneItem *i); + +int dns_zone_check_conflicts(DnsZone *zone, DnsResourceRecord *rr); +int dns_zone_verify_conflicts(DnsZone *zone, DnsResourceKey *key); + +void dns_zone_verify_all(DnsZone *zone); + +void dns_zone_item_probe_stop(DnsZoneItem *i); + +void dns_zone_dump(DnsZone *zone, FILE *f); +bool dns_zone_is_empty(DnsZone *zone); diff --git a/src/grp-resolve/systemd-resolved/resolved-etc-hosts.c b/src/grp-resolve/systemd-resolved/resolved-etc-hosts.c new file mode 100644 index 0000000000..942c06605e --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-etc-hosts.c @@ -0,0 +1,449 @@ +/*** + This file is part of systemd. + + Copyright 2016 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include "systemd-basic/fd-util.h" +#include "systemd-basic/fileio.h" +#include "systemd-basic/hostname-util.h" +#include "systemd-basic/string-util.h" +#include "systemd-basic/strv.h" +#include "systemd-basic/time-util.h" + +#include "resolved-dns-synthesize.h" +#include "resolved-etc-hosts.h" + +/* Recheck /etc/hosts at most once every 2s */ +#define ETC_HOSTS_RECHECK_USEC (2*USEC_PER_SEC) + +typedef struct EtcHostsItem { + int family; + union in_addr_union address; + + char **names; +} EtcHostsItem; + +typedef struct EtcHostsItemByName { + char *name; + + EtcHostsItem **items; + size_t n_items, n_allocated; +} EtcHostsItemByName; + +void manager_etc_hosts_flush(Manager *m) { + EtcHostsItem *item; + EtcHostsItemByName *bn; + + while ((item = set_steal_first(m->etc_hosts_by_address))) { + strv_free(item->names); + free(item); + } + + while ((bn = hashmap_steal_first(m->etc_hosts_by_name))) { + free(bn->name); + free(bn->items); + free(bn); + } + + m->etc_hosts_by_address = set_free(m->etc_hosts_by_address); + m->etc_hosts_by_name = hashmap_free(m->etc_hosts_by_name); + + m->etc_hosts_mtime = USEC_INFINITY; +} + +static void etc_hosts_item_hash_func(const void *p, struct siphash *state) { + const EtcHostsItem *item = p; + + siphash24_compress(&item->family, sizeof(item->family), state); + + if (item->family == AF_INET) + siphash24_compress(&item->address.in, sizeof(item->address.in), state); + else if (item->family == AF_INET6) + siphash24_compress(&item->address.in6, sizeof(item->address.in6), state); +} + +static int etc_hosts_item_compare_func(const void *a, const void *b) { + const EtcHostsItem *x = a, *y = b; + + if (x->family != y->family) + return x->family - y->family; + + if (x->family == AF_INET) + return memcmp(&x->address.in.s_addr, &y->address.in.s_addr, sizeof(struct in_addr)); + + if (x->family == AF_INET6) + return memcmp(&x->address.in6.s6_addr, &y->address.in6.s6_addr, sizeof(struct in6_addr)); + + return trivial_compare_func(a, b); +} + +static const struct hash_ops etc_hosts_item_ops = { + .hash = etc_hosts_item_hash_func, + .compare = etc_hosts_item_compare_func, +}; + +static int add_item(Manager *m, int family, const union in_addr_union *address, char **names) { + + EtcHostsItem key = { + .family = family, + .address = *address, + }; + EtcHostsItem *item; + char **n; + int r; + + assert(m); + assert(address); + + r = in_addr_is_null(family, address); + if (r < 0) + return r; + if (r > 0) + /* This is an 0.0.0.0 or :: item, which we assume means that we shall map the specified hostname to + * nothing. */ + item = NULL; + else { + /* If this is a normal address, then, simply add entry mapping it to the specified names */ + + item = set_get(m->etc_hosts_by_address, &key); + if (item) { + r = strv_extend_strv(&item->names, names, true); + if (r < 0) + return log_oom(); + } else { + + r = set_ensure_allocated(&m->etc_hosts_by_address, &etc_hosts_item_ops); + if (r < 0) + return log_oom(); + + item = new0(EtcHostsItem, 1); + if (!item) + return log_oom(); + + item->family = family; + item->address = *address; + item->names = names; + + r = set_put(m->etc_hosts_by_address, item); + if (r < 0) { + free(item); + return log_oom(); + } + } + } + + STRV_FOREACH(n, names) { + EtcHostsItemByName *bn; + + bn = hashmap_get(m->etc_hosts_by_name, *n); + if (!bn) { + r = hashmap_ensure_allocated(&m->etc_hosts_by_name, &dns_name_hash_ops); + if (r < 0) + return log_oom(); + + bn = new0(EtcHostsItemByName, 1); + if (!bn) + return log_oom(); + + bn->name = strdup(*n); + if (!bn->name) { + free(bn); + return log_oom(); + } + + r = hashmap_put(m->etc_hosts_by_name, bn->name, bn); + if (r < 0) { + free(bn->name); + free(bn); + return log_oom(); + } + } + + if (item) { + if (!GREEDY_REALLOC(bn->items, bn->n_allocated, bn->n_items+1)) + return log_oom(); + + bn->items[bn->n_items++] = item; + } + } + + return 0; +} + +static int parse_line(Manager *m, unsigned nr, const char *line) { + _cleanup_free_ char *address = NULL; + _cleanup_strv_free_ char **names = NULL; + union in_addr_union in; + bool suppressed = false; + int family, r; + + assert(m); + assert(line); + + r = extract_first_word(&line, &address, NULL, EXTRACT_RELAX); + if (r < 0) + return log_error_errno(r, "Couldn't extract address, in line /etc/hosts:%u.", nr); + if (r == 0) { + log_error("Premature end of line, in line /etc/hosts:%u.", nr); + return -EINVAL; + } + + r = in_addr_from_string_auto(address, &family, &in); + if (r < 0) + return log_error_errno(r, "Address '%s' is invalid, in line /etc/hosts:%u.", address, nr); + + for (;;) { + _cleanup_free_ char *name = NULL; + + r = extract_first_word(&line, &name, NULL, EXTRACT_RELAX); + if (r < 0) + return log_error_errno(r, "Couldn't extract host name, in line /etc/hosts:%u.", nr); + if (r == 0) + break; + + r = dns_name_is_valid(name); + if (r <= 0) + return log_error_errno(r, "Hostname %s is not valid, ignoring, in line /etc/hosts:%u.", name, nr); + + if (is_localhost(name)) { + /* Suppress the "localhost" line that is often seen */ + suppressed = true; + continue; + } + + r = strv_push(&names, name); + if (r < 0) + return log_oom(); + + name = NULL; + } + + if (strv_isempty(names)) { + + if (suppressed) + return 0; + + log_error("Line is missing any host names, in line /etc/hosts:%u.", nr); + return -EINVAL; + } + + /* Takes possession of the names strv */ + r = add_item(m, family, &in, names); + if (r < 0) + return r; + + names = NULL; + return r; +} + +int manager_etc_hosts_read(Manager *m) { + _cleanup_fclose_ FILE *f = NULL; + char line[LINE_MAX]; + struct stat st; + usec_t ts; + unsigned nr = 0; + int r; + + assert_se(sd_event_now(m->event, clock_boottime_or_monotonic(), &ts) >= 0); + + /* See if we checked /etc/hosts recently already */ + if (m->etc_hosts_last != USEC_INFINITY && m->etc_hosts_last + ETC_HOSTS_RECHECK_USEC > ts) + return 0; + + m->etc_hosts_last = ts; + + if (m->etc_hosts_mtime != USEC_INFINITY) { + if (stat("/etc/hosts", &st) < 0) { + if (errno == ENOENT) { + r = 0; + goto clear; + } + + return log_error_errno(errno, "Failed to stat /etc/hosts: %m"); + } + + /* Did the mtime change? If not, there's no point in re-reading the file. */ + if (timespec_load(&st.st_mtim) == m->etc_hosts_mtime) + return 0; + } + + f = fopen("/etc/hosts", "re"); + if (!f) { + if (errno == ENOENT) { + r = 0; + goto clear; + } + + return log_error_errno(errno, "Failed to open /etc/hosts: %m"); + } + + /* Take the timestamp at the beginning of processing, so that any changes made later are read on the next + * invocation */ + r = fstat(fileno(f), &st); + if (r < 0) + return log_error_errno(errno, "Failed to fstat() /etc/hosts: %m"); + + manager_etc_hosts_flush(m); + + FOREACH_LINE(line, f, return log_error_errno(errno, "Failed to read /etc/hosts: %m")) { + char *l; + + nr++; + + l = strstrip(line); + if (isempty(l)) + continue; + if (l[0] == '#') + continue; + + r = parse_line(m, nr, l); + if (r == -ENOMEM) /* On OOM we abandon the half-built-up structure. All other errors we ignore and proceed */ + goto clear; + } + + m->etc_hosts_mtime = timespec_load(&st.st_mtim); + m->etc_hosts_last = ts; + + return 1; + +clear: + manager_etc_hosts_flush(m); + return r; +} + +int manager_etc_hosts_lookup(Manager *m, DnsQuestion* q, DnsAnswer **answer) { + bool found_a = false, found_aaaa = false; + EtcHostsItemByName *bn; + EtcHostsItem k = {}; + DnsResourceKey *t; + const char *name; + unsigned i; + int r; + + assert(m); + assert(q); + assert(answer); + + r = manager_etc_hosts_read(m); + if (r < 0) + return r; + + name = dns_question_first_name(q); + if (!name) + return 0; + + r = dns_name_address(name, &k.family, &k.address); + if (r > 0) { + EtcHostsItem *item; + DnsResourceKey *found_ptr = NULL; + + item = set_get(m->etc_hosts_by_address, &k); + if (!item) + return 0; + + /* We have an address in /etc/hosts that matches the queried name. Let's return successful. Actual data + * we'll only return if the request was for PTR. */ + + DNS_QUESTION_FOREACH(t, q) { + if (!IN_SET(t->type, DNS_TYPE_PTR, DNS_TYPE_ANY)) + continue; + if (!IN_SET(t->class, DNS_CLASS_IN, DNS_CLASS_ANY)) + continue; + + r = dns_name_equal(dns_resource_key_name(t), name); + if (r < 0) + return r; + if (r > 0) { + found_ptr = t; + break; + } + } + + if (found_ptr) { + char **n; + + r = dns_answer_reserve(answer, strv_length(item->names)); + if (r < 0) + return r; + + STRV_FOREACH(n, item->names) { + _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL; + + rr = dns_resource_record_new(found_ptr); + if (!rr) + return -ENOMEM; + + rr->ptr.name = strdup(*n); + if (!rr->ptr.name) + return -ENOMEM; + + r = dns_answer_add(*answer, rr, 0, DNS_ANSWER_AUTHENTICATED); + if (r < 0) + return r; + } + } + + return 1; + } + + bn = hashmap_get(m->etc_hosts_by_name, name); + if (!bn) + return 0; + + r = dns_answer_reserve(answer, bn->n_items); + if (r < 0) + return r; + + DNS_QUESTION_FOREACH(t, q) { + if (!IN_SET(t->type, DNS_TYPE_A, DNS_TYPE_AAAA, DNS_TYPE_ANY)) + continue; + if (!IN_SET(t->class, DNS_CLASS_IN, DNS_CLASS_ANY)) + continue; + + r = dns_name_equal(dns_resource_key_name(t), name); + if (r < 0) + return r; + if (r == 0) + continue; + + if (IN_SET(t->type, DNS_TYPE_A, DNS_TYPE_ANY)) + found_a = true; + if (IN_SET(t->type, DNS_TYPE_AAAA, DNS_TYPE_ANY)) + found_aaaa = true; + + if (found_a && found_aaaa) + break; + } + + for (i = 0; i < bn->n_items; i++) { + _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL; + + if ((found_a && bn->items[i]->family != AF_INET) && + (found_aaaa && bn->items[i]->family != AF_INET6)) + continue; + + r = dns_resource_record_new_address(&rr, bn->items[i]->family, &bn->items[i]->address, bn->name); + if (r < 0) + return r; + + r = dns_answer_add(*answer, rr, 0, DNS_ANSWER_AUTHENTICATED); + if (r < 0) + return r; + } + + return 1; +} diff --git a/src/grp-resolve/systemd-resolved/resolved-etc-hosts.h b/src/grp-resolve/systemd-resolved/resolved-etc-hosts.h new file mode 100644 index 0000000000..49e449b56d --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-etc-hosts.h @@ -0,0 +1,29 @@ +#pragma once + +/*** + This file is part of systemd. + + Copyright 2016 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include "basic-dns/resolved-dns-answer.h" +#include "basic-dns/resolved-dns-question.h" + +#include "resolved-manager.h" + +void manager_etc_hosts_flush(Manager *m); +int manager_etc_hosts_read(Manager *m); +int manager_etc_hosts_lookup(Manager *m, DnsQuestion* q, DnsAnswer **answer); diff --git a/src/grp-resolve/systemd-resolved/resolved-gperf.gperf b/src/grp-resolve/systemd-resolved/resolved-gperf.gperf new file mode 100644 index 0000000000..79e54d8357 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-gperf.gperf @@ -0,0 +1,25 @@ +%{ +#include <stddef.h> + +#include "systemd-shared/conf-parser.h" + +#include "resolved-conf.h" +%} +struct ConfigPerfItem; +%null_strings +%language=ANSI-C +%define slot-name section_and_lvalue +%define hash-function-name resolved_gperf_hash +%define lookup-function-name resolved_gperf_lookup +%readonly-tables +%omit-struct-type +%struct-type +%includes +%% +Resolve.DNS, config_parse_dns_servers, DNS_SERVER_SYSTEM, 0 +Resolve.FallbackDNS, config_parse_dns_servers, DNS_SERVER_FALLBACK, 0 +Resolve.Domains, config_parse_search_domains, 0, 0 +Resolve.LLMNR, config_parse_resolve_support, 0, offsetof(Manager, llmnr_support) +Resolve.DNSSEC, config_parse_dnssec_mode, 0, offsetof(Manager, dnssec_mode) +Resolve.Cache, config_parse_bool, 0, offsetof(Manager, enable_cache) +Resolve.DNSStubListener, config_parse_dns_stub_listener_mode, 0, offsetof(Manager, dns_stub_listener_mode) diff --git a/src/grp-resolve/systemd-resolved/resolved-link-bus.c b/src/grp-resolve/systemd-resolved/resolved-link-bus.c new file mode 100644 index 0000000000..bea3c35829 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-link-bus.c @@ -0,0 +1,630 @@ +/*** + This file is part of systemd. + + Copyright 2016 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include "sd-bus/bus-common-errors.h" +#include "sd-bus/bus-util.h" +#include "systemd-basic/alloc-util.h" +#include "systemd-basic/parse-util.h" +#include "systemd-basic/strv.h" +#include "systemd-shared/resolve-util.h" + +#include "resolved-bus.h" +#include "resolved-link-bus.h" +#include "resolved-resolv-conf.h" + +static BUS_DEFINE_PROPERTY_GET_ENUM(property_get_resolve_support, resolve_support, ResolveSupport); + +static int property_get_dnssec_mode( + sd_bus *bus, + const char *path, + const char *interface, + const char *property, + sd_bus_message *reply, + void *userdata, + sd_bus_error *error) { + + Link *l = userdata; + + assert(reply); + assert(l); + + return sd_bus_message_append(reply, "s", dnssec_mode_to_string(link_get_dnssec_mode(l))); +} + +static int property_get_dns( + sd_bus *bus, + const char *path, + const char *interface, + const char *property, + sd_bus_message *reply, + void *userdata, + sd_bus_error *error) { + + Link *l = userdata; + DnsServer *s; + int r; + + assert(reply); + assert(l); + + r = sd_bus_message_open_container(reply, 'a', "(iay)"); + if (r < 0) + return r; + + LIST_FOREACH(servers, s, l->dns_servers) { + r = bus_dns_server_append(reply, s, false); + if (r < 0) + return r; + } + + return sd_bus_message_close_container(reply); +} + +static int property_get_domains( + sd_bus *bus, + const char *path, + const char *interface, + const char *property, + sd_bus_message *reply, + void *userdata, + sd_bus_error *error) { + + Link *l = userdata; + DnsSearchDomain *d; + int r; + + assert(reply); + assert(l); + + r = sd_bus_message_open_container(reply, 'a', "(sb)"); + if (r < 0) + return r; + + LIST_FOREACH(domains, d, l->search_domains) { + r = sd_bus_message_append(reply, "(sb)", d->name, d->route_only); + if (r < 0) + return r; + } + + return sd_bus_message_close_container(reply); +} + +static int property_get_scopes_mask( + sd_bus *bus, + const char *path, + const char *interface, + const char *property, + sd_bus_message *reply, + void *userdata, + sd_bus_error *error) { + + Link *l = userdata; + uint64_t mask; + + assert(reply); + assert(l); + + mask = (l->unicast_scope ? SD_RESOLVED_DNS : 0) | + (l->llmnr_ipv4_scope ? SD_RESOLVED_LLMNR_IPV4 : 0) | + (l->llmnr_ipv6_scope ? SD_RESOLVED_LLMNR_IPV6 : 0) | + (l->mdns_ipv4_scope ? SD_RESOLVED_MDNS_IPV4 : 0) | + (l->mdns_ipv6_scope ? SD_RESOLVED_MDNS_IPV6 : 0); + + return sd_bus_message_append(reply, "t", mask); +} + +static int property_get_ntas( + sd_bus *bus, + const char *path, + const char *interface, + const char *property, + sd_bus_message *reply, + void *userdata, + sd_bus_error *error) { + + Link *l = userdata; + const char *name; + Iterator i; + int r; + + assert(reply); + assert(l); + + r = sd_bus_message_open_container(reply, 'a', "s"); + if (r < 0) + return r; + + SET_FOREACH(name, l->dnssec_negative_trust_anchors, i) { + r = sd_bus_message_append(reply, "s", name); + if (r < 0) + return r; + } + + return sd_bus_message_close_container(reply); +} + +static int property_get_dnssec_supported( + sd_bus *bus, + const char *path, + const char *interface, + const char *property, + sd_bus_message *reply, + void *userdata, + sd_bus_error *error) { + + Link *l = userdata; + + assert(reply); + assert(l); + + return sd_bus_message_append(reply, "b", link_dnssec_supported(l)); +} + +static int verify_unmanaged_link(Link *l, sd_bus_error *error) { + assert(l); + + if (l->flags & IFF_LOOPBACK) + return sd_bus_error_setf(error, BUS_ERROR_LINK_BUSY, "Link %s is loopback device.", l->name); + if (l->is_managed) + return sd_bus_error_setf(error, BUS_ERROR_LINK_BUSY, "Link %s is managed.", l->name); + + return 0; +} + +int bus_link_method_set_dns_servers(sd_bus_message *message, void *userdata, sd_bus_error *error) { + _cleanup_free_ struct in_addr_data *dns = NULL; + size_t allocated = 0, n = 0; + Link *l = userdata; + unsigned i; + int r; + + assert(message); + assert(l); + + r = verify_unmanaged_link(l, error); + if (r < 0) + return r; + + r = sd_bus_message_enter_container(message, 'a', "(iay)"); + if (r < 0) + return r; + + for (;;) { + int family; + size_t sz; + const void *d; + + assert_cc(sizeof(int) == sizeof(int32_t)); + + r = sd_bus_message_enter_container(message, 'r', "iay"); + if (r < 0) + return r; + if (r == 0) + break; + + r = sd_bus_message_read(message, "i", &family); + if (r < 0) + return r; + + if (!IN_SET(family, AF_INET, AF_INET6)) + return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Unknown address family %i", family); + + r = sd_bus_message_read_array(message, 'y', &d, &sz); + if (r < 0) + return r; + if (sz != FAMILY_ADDRESS_SIZE(family)) + return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid address size"); + + if (!dns_server_address_valid(family, d)) + return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid DNS server address"); + + r = sd_bus_message_exit_container(message); + if (r < 0) + return r; + + if (!GREEDY_REALLOC(dns, allocated, n+1)) + return -ENOMEM; + + dns[n].family = family; + memcpy(&dns[n].address, d, sz); + n++; + } + + r = sd_bus_message_exit_container(message); + if (r < 0) + return r; + + dns_server_mark_all(l->dns_servers); + + for (i = 0; i < n; i++) { + DnsServer *s; + + s = dns_server_find(l->dns_servers, dns[i].family, &dns[i].address, 0); + if (s) + dns_server_move_back_and_unmark(s); + else { + r = dns_server_new(l->manager, NULL, DNS_SERVER_LINK, l, dns[i].family, &dns[i].address, 0); + if (r < 0) + goto clear; + } + + } + + dns_server_unlink_marked(l->dns_servers); + link_allocate_scopes(l); + + (void) link_save_user(l); + (void) manager_write_resolv_conf(l->manager); + + return sd_bus_reply_method_return(message, NULL); + +clear: + dns_server_unlink_all(l->dns_servers); + return r; +} + +int bus_link_method_set_domains(sd_bus_message *message, void *userdata, sd_bus_error *error) { + Link *l = userdata; + int r; + + assert(message); + assert(l); + + r = verify_unmanaged_link(l, error); + if (r < 0) + return r; + + r = sd_bus_message_enter_container(message, 'a', "(sb)"); + if (r < 0) + return r; + + for (;;) { + const char *name; + int route_only; + + r = sd_bus_message_read(message, "(sb)", &name, &route_only); + if (r < 0) + return r; + if (r == 0) + break; + + r = dns_name_is_valid(name); + if (r < 0) + return r; + if (r == 0) + return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid search domain %s", name); + if (!route_only && dns_name_is_root(name)) + return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Root domain is not suitable as search domain"); + } + + dns_search_domain_mark_all(l->search_domains); + + r = sd_bus_message_rewind(message, false); + if (r < 0) + return r; + + for (;;) { + DnsSearchDomain *d; + const char *name; + int route_only; + + r = sd_bus_message_read(message, "(sb)", &name, &route_only); + if (r < 0) + goto clear; + if (r == 0) + break; + + r = dns_search_domain_find(l->search_domains, name, &d); + if (r < 0) + goto clear; + + if (r > 0) + dns_search_domain_move_back_and_unmark(d); + else { + r = dns_search_domain_new(l->manager, &d, DNS_SEARCH_DOMAIN_LINK, l, name); + if (r < 0) + goto clear; + } + + d->route_only = route_only; + } + + r = sd_bus_message_exit_container(message); + if (r < 0) + goto clear; + + dns_search_domain_unlink_marked(l->search_domains); + + (void) link_save_user(l); + (void) manager_write_resolv_conf(l->manager); + + return sd_bus_reply_method_return(message, NULL); + +clear: + dns_search_domain_unlink_all(l->search_domains); + return r; +} + +int bus_link_method_set_llmnr(sd_bus_message *message, void *userdata, sd_bus_error *error) { + Link *l = userdata; + ResolveSupport mode; + const char *llmnr; + int r; + + assert(message); + assert(l); + + r = verify_unmanaged_link(l, error); + if (r < 0) + return r; + + r = sd_bus_message_read(message, "s", &llmnr); + if (r < 0) + return r; + + if (isempty(llmnr)) + mode = RESOLVE_SUPPORT_YES; + else { + mode = resolve_support_from_string(llmnr); + if (mode < 0) + return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid LLMNR setting: %s", llmnr); + } + + l->llmnr_support = mode; + link_allocate_scopes(l); + link_add_rrs(l, false); + + (void) link_save_user(l); + + return sd_bus_reply_method_return(message, NULL); +} + +int bus_link_method_set_mdns(sd_bus_message *message, void *userdata, sd_bus_error *error) { + Link *l = userdata; + ResolveSupport mode; + const char *mdns; + int r; + + assert(message); + assert(l); + + r = verify_unmanaged_link(l, error); + if (r < 0) + return r; + + r = sd_bus_message_read(message, "s", &mdns); + if (r < 0) + return r; + + if (isempty(mdns)) + mode = RESOLVE_SUPPORT_NO; + else { + mode = resolve_support_from_string(mdns); + if (mode < 0) + return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid MulticastDNS setting: %s", mdns); + } + + l->mdns_support = mode; + link_allocate_scopes(l); + link_add_rrs(l, false); + + (void) link_save_user(l); + + return sd_bus_reply_method_return(message, NULL); +} + +int bus_link_method_set_dnssec(sd_bus_message *message, void *userdata, sd_bus_error *error) { + Link *l = userdata; + const char *dnssec; + DnssecMode mode; + int r; + + assert(message); + assert(l); + + r = verify_unmanaged_link(l, error); + if (r < 0) + return r; + + r = sd_bus_message_read(message, "s", &dnssec); + if (r < 0) + return r; + + if (isempty(dnssec)) + mode = _DNSSEC_MODE_INVALID; + else { + mode = dnssec_mode_from_string(dnssec); + if (mode < 0) + return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid DNSSEC setting: %s", dnssec); + } + + link_set_dnssec_mode(l, mode); + + (void) link_save_user(l); + + return sd_bus_reply_method_return(message, NULL); +} + +int bus_link_method_set_dnssec_negative_trust_anchors(sd_bus_message *message, void *userdata, sd_bus_error *error) { + _cleanup_set_free_free_ Set *ns = NULL; + _cleanup_free_ char **ntas = NULL; + Link *l = userdata; + int r; + char **i; + + assert(message); + assert(l); + + r = verify_unmanaged_link(l, error); + if (r < 0) + return r; + + r = sd_bus_message_read_strv(message, &ntas); + if (r < 0) + return r; + + STRV_FOREACH(i, ntas) { + r = dns_name_is_valid(*i); + if (r < 0) + return r; + if (r == 0) + return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid negative trust anchor domain: %s", *i); + } + + ns = set_new(&dns_name_hash_ops); + if (!ns) + return -ENOMEM; + + STRV_FOREACH(i, ntas) { + r = set_put_strdup(ns, *i); + if (r < 0) + return r; + } + + set_free_free(l->dnssec_negative_trust_anchors); + l->dnssec_negative_trust_anchors = ns; + ns = NULL; + + (void) link_save_user(l); + + return sd_bus_reply_method_return(message, NULL); +} + +int bus_link_method_revert(sd_bus_message *message, void *userdata, sd_bus_error *error) { + Link *l = userdata; + int r; + + assert(message); + assert(l); + + r = verify_unmanaged_link(l, error); + if (r < 0) + return r; + + link_flush_settings(l); + link_allocate_scopes(l); + link_add_rrs(l, false); + + (void) link_save_user(l); + (void) manager_write_resolv_conf(l->manager); + + return sd_bus_reply_method_return(message, NULL); +} + +const sd_bus_vtable link_vtable[] = { + SD_BUS_VTABLE_START(0), + + SD_BUS_PROPERTY("ScopesMask", "t", property_get_scopes_mask, 0, 0), + SD_BUS_PROPERTY("DNS", "a(iay)", property_get_dns, 0, 0), + SD_BUS_PROPERTY("Domains", "a(sb)", property_get_domains, 0, 0), + SD_BUS_PROPERTY("LLMNR", "s", property_get_resolve_support, offsetof(Link, llmnr_support), 0), + SD_BUS_PROPERTY("MulticastDNS", "s", property_get_resolve_support, offsetof(Link, mdns_support), 0), + SD_BUS_PROPERTY("DNSSEC", "s", property_get_dnssec_mode, 0, 0), + SD_BUS_PROPERTY("DNSSECNegativeTrustAnchors", "as", property_get_ntas, 0, 0), + SD_BUS_PROPERTY("DNSSECSupported", "b", property_get_dnssec_supported, 0, 0), + + SD_BUS_METHOD("SetDNS", "a(iay)", NULL, bus_link_method_set_dns_servers, 0), + SD_BUS_METHOD("SetDomains", "a(sb)", NULL, bus_link_method_set_domains, 0), + SD_BUS_METHOD("SetLLMNR", "s", NULL, bus_link_method_set_llmnr, 0), + SD_BUS_METHOD("SetMulticastDNS", "s", NULL, bus_link_method_set_mdns, 0), + SD_BUS_METHOD("SetDNSSEC", "s", NULL, bus_link_method_set_dnssec, 0), + SD_BUS_METHOD("SetDNSSECNegativeTrustAnchors", "as", NULL, bus_link_method_set_dnssec_negative_trust_anchors, 0), + SD_BUS_METHOD("Revert", NULL, NULL, bus_link_method_revert, 0), + + SD_BUS_VTABLE_END +}; + +int link_object_find(sd_bus *bus, const char *path, const char *interface, void *userdata, void **found, sd_bus_error *error) { + _cleanup_free_ char *e = NULL; + Manager *m = userdata; + int ifindex; + Link *link; + int r; + + assert(bus); + assert(path); + assert(interface); + assert(found); + assert(m); + + r = sd_bus_path_decode(path, "/org/freedesktop/resolve1/link", &e); + if (r <= 0) + return 0; + + r = parse_ifindex(e, &ifindex); + if (r < 0) + return 0; + + link = hashmap_get(m->links, INT_TO_PTR(ifindex)); + if (!link) + return 0; + + *found = link; + return 1; +} + +char *link_bus_path(Link *link) { + _cleanup_free_ char *ifindex = NULL; + char *p; + int r; + + assert(link); + + if (asprintf(&ifindex, "%i", link->ifindex) < 0) + return NULL; + + r = sd_bus_path_encode("/org/freedesktop/resolve1/link", ifindex, &p); + if (r < 0) + return NULL; + + return p; +} + +int link_node_enumerator(sd_bus *bus, const char *path, void *userdata, char ***nodes, sd_bus_error *error) { + _cleanup_strv_free_ char **l = NULL; + Manager *m = userdata; + Link *link; + Iterator i; + unsigned c = 0; + + assert(bus); + assert(path); + assert(m); + assert(nodes); + + l = new0(char*, hashmap_size(m->links) + 1); + if (!l) + return -ENOMEM; + + HASHMAP_FOREACH(link, m->links, i) { + char *p; + + p = link_bus_path(link); + if (!p) + return -ENOMEM; + + l[c++] = p; + } + + l[c] = NULL; + *nodes = l; + l = NULL; + + return 1; +} diff --git a/src/grp-resolve/systemd-resolved/resolved-link-bus.h b/src/grp-resolve/systemd-resolved/resolved-link-bus.h new file mode 100644 index 0000000000..b1ac57961d --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-link-bus.h @@ -0,0 +1,38 @@ +#pragma once + +/*** + This file is part of systemd. + + Copyright 2016 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include <systemd/sd-bus.h> + +#include "resolved-link.h" + +extern const sd_bus_vtable link_vtable[]; + +int link_object_find(sd_bus *bus, const char *path, const char *interface, void *userdata, void **found, sd_bus_error *error); +char *link_bus_path(Link *link); +int link_node_enumerator(sd_bus *bus, const char *path, void *userdata, char ***nodes, sd_bus_error *error); + +int bus_link_method_set_dns_servers(sd_bus_message *message, void *userdata, sd_bus_error *error); +int bus_link_method_set_domains(sd_bus_message *message, void *userdata, sd_bus_error *error); +int bus_link_method_set_llmnr(sd_bus_message *message, void *userdata, sd_bus_error *error); +int bus_link_method_set_mdns(sd_bus_message *message, void *userdata, sd_bus_error *error); +int bus_link_method_set_dnssec(sd_bus_message *message, void *userdata, sd_bus_error *error); +int bus_link_method_set_dnssec_negative_trust_anchors(sd_bus_message *message, void *userdata, sd_bus_error *error); +int bus_link_method_revert(sd_bus_message *message, void *userdata, sd_bus_error *error); diff --git a/src/grp-resolve/systemd-resolved/resolved-link.c b/src/grp-resolve/systemd-resolved/resolved-link.c new file mode 100644 index 0000000000..99be607b09 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-link.c @@ -0,0 +1,1113 @@ +/*** + This file is part of systemd. + + Copyright 2014 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include <net/if.h> + +#include "systemd-basic/alloc-util.h" +#include "systemd-basic/fd-util.h" +#include "systemd-basic/fileio.h" +#include "systemd-basic/missing.h" +#include "systemd-basic/mkdir.h" +#include "systemd-basic/parse-util.h" +#include "systemd-basic/string-util.h" +#include "systemd-basic/strv.h" +#include "systemd-staging/sd-network.h" + +#include "resolved-link.h" + +int link_new(Manager *m, Link **ret, int ifindex) { + _cleanup_(link_freep) Link *l = NULL; + int r; + + assert(m); + assert(ifindex > 0); + + r = hashmap_ensure_allocated(&m->links, NULL); + if (r < 0) + return r; + + l = new0(Link, 1); + if (!l) + return -ENOMEM; + + l->ifindex = ifindex; + l->llmnr_support = RESOLVE_SUPPORT_YES; + l->mdns_support = RESOLVE_SUPPORT_NO; + l->dnssec_mode = _DNSSEC_MODE_INVALID; + l->operstate = IF_OPER_UNKNOWN; + + if (asprintf(&l->state_file, "/run/systemd/resolve/netif/%i", ifindex) < 0) + return -ENOMEM; + + r = hashmap_put(m->links, INT_TO_PTR(ifindex), l); + if (r < 0) + return r; + + l->manager = m; + + if (ret) + *ret = l; + l = NULL; + + return 0; +} + +void link_flush_settings(Link *l) { + assert(l); + + l->llmnr_support = RESOLVE_SUPPORT_YES; + l->mdns_support = RESOLVE_SUPPORT_NO; + l->dnssec_mode = _DNSSEC_MODE_INVALID; + + dns_server_unlink_all(l->dns_servers); + dns_search_domain_unlink_all(l->search_domains); + + l->dnssec_negative_trust_anchors = set_free_free(l->dnssec_negative_trust_anchors); +} + +Link *link_free(Link *l) { + if (!l) + return NULL; + + link_flush_settings(l); + + while (l->addresses) + (void) link_address_free(l->addresses); + + if (l->manager) + hashmap_remove(l->manager->links, INT_TO_PTR(l->ifindex)); + + dns_scope_free(l->unicast_scope); + dns_scope_free(l->llmnr_ipv4_scope); + dns_scope_free(l->llmnr_ipv6_scope); + dns_scope_free(l->mdns_ipv4_scope); + dns_scope_free(l->mdns_ipv6_scope); + + free(l->state_file); + + return mfree(l); +} + +void link_allocate_scopes(Link *l) { + int r; + + assert(l); + + if (link_relevant(l, AF_UNSPEC, false) && + l->dns_servers) { + if (!l->unicast_scope) { + r = dns_scope_new(l->manager, &l->unicast_scope, l, DNS_PROTOCOL_DNS, AF_UNSPEC); + if (r < 0) + log_warning_errno(r, "Failed to allocate DNS scope: %m"); + } + } else + l->unicast_scope = dns_scope_free(l->unicast_scope); + + if (link_relevant(l, AF_INET, true) && + l->llmnr_support != RESOLVE_SUPPORT_NO && + l->manager->llmnr_support != RESOLVE_SUPPORT_NO) { + if (!l->llmnr_ipv4_scope) { + r = dns_scope_new(l->manager, &l->llmnr_ipv4_scope, l, DNS_PROTOCOL_LLMNR, AF_INET); + if (r < 0) + log_warning_errno(r, "Failed to allocate LLMNR IPv4 scope: %m"); + } + } else + l->llmnr_ipv4_scope = dns_scope_free(l->llmnr_ipv4_scope); + + if (link_relevant(l, AF_INET6, true) && + l->llmnr_support != RESOLVE_SUPPORT_NO && + l->manager->llmnr_support != RESOLVE_SUPPORT_NO && + socket_ipv6_is_supported()) { + if (!l->llmnr_ipv6_scope) { + r = dns_scope_new(l->manager, &l->llmnr_ipv6_scope, l, DNS_PROTOCOL_LLMNR, AF_INET6); + if (r < 0) + log_warning_errno(r, "Failed to allocate LLMNR IPv6 scope: %m"); + } + } else + l->llmnr_ipv6_scope = dns_scope_free(l->llmnr_ipv6_scope); + + if (link_relevant(l, AF_INET, true) && + l->mdns_support != RESOLVE_SUPPORT_NO && + l->manager->mdns_support != RESOLVE_SUPPORT_NO) { + if (!l->mdns_ipv4_scope) { + r = dns_scope_new(l->manager, &l->mdns_ipv4_scope, l, DNS_PROTOCOL_MDNS, AF_INET); + if (r < 0) + log_warning_errno(r, "Failed to allocate mDNS IPv4 scope: %m"); + } + } else + l->mdns_ipv4_scope = dns_scope_free(l->mdns_ipv4_scope); + + if (link_relevant(l, AF_INET6, true) && + l->mdns_support != RESOLVE_SUPPORT_NO && + l->manager->mdns_support != RESOLVE_SUPPORT_NO) { + if (!l->mdns_ipv6_scope) { + r = dns_scope_new(l->manager, &l->mdns_ipv6_scope, l, DNS_PROTOCOL_MDNS, AF_INET6); + if (r < 0) + log_warning_errno(r, "Failed to allocate mDNS IPv6 scope: %m"); + } + } else + l->mdns_ipv6_scope = dns_scope_free(l->mdns_ipv6_scope); +} + +void link_add_rrs(Link *l, bool force_remove) { + LinkAddress *a; + + LIST_FOREACH(addresses, a, l->addresses) + link_address_add_rrs(a, force_remove); +} + +int link_process_rtnl(Link *l, sd_netlink_message *m) { + const char *n = NULL; + int r; + + assert(l); + assert(m); + + r = sd_rtnl_message_link_get_flags(m, &l->flags); + if (r < 0) + return r; + + (void) sd_netlink_message_read_u32(m, IFLA_MTU, &l->mtu); + (void) sd_netlink_message_read_u8(m, IFLA_OPERSTATE, &l->operstate); + + if (sd_netlink_message_read_string(m, IFLA_IFNAME, &n) >= 0) { + strncpy(l->name, n, sizeof(l->name)-1); + char_array_0(l->name); + } + + link_allocate_scopes(l); + link_add_rrs(l, false); + + return 0; +} + +static int link_update_dns_server_one(Link *l, const char *name) { + union in_addr_union a; + DnsServer *s; + int family, r; + + assert(l); + assert(name); + + r = in_addr_from_string_auto(name, &family, &a); + if (r < 0) + return r; + + s = dns_server_find(l->dns_servers, family, &a, 0); + if (s) { + dns_server_move_back_and_unmark(s); + return 0; + } + + return dns_server_new(l->manager, NULL, DNS_SERVER_LINK, l, family, &a, 0); +} + +static int link_update_dns_servers(Link *l) { + _cleanup_strv_free_ char **nameservers = NULL; + char **nameserver; + int r; + + assert(l); + + r = sd_network_link_get_dns(l->ifindex, &nameservers); + if (r == -ENODATA) { + r = 0; + goto clear; + } + if (r < 0) + goto clear; + + dns_server_mark_all(l->dns_servers); + + STRV_FOREACH(nameserver, nameservers) { + r = link_update_dns_server_one(l, *nameserver); + if (r < 0) + goto clear; + } + + dns_server_unlink_marked(l->dns_servers); + return 0; + +clear: + dns_server_unlink_all(l->dns_servers); + return r; +} + +static int link_update_llmnr_support(Link *l) { + _cleanup_free_ char *b = NULL; + int r; + + assert(l); + + r = sd_network_link_get_llmnr(l->ifindex, &b); + if (r == -ENODATA) { + r = 0; + goto clear; + } + if (r < 0) + goto clear; + + l->llmnr_support = resolve_support_from_string(b); + if (l->llmnr_support < 0) { + r = -EINVAL; + goto clear; + } + + return 0; + +clear: + l->llmnr_support = RESOLVE_SUPPORT_YES; + return r; +} + +static int link_update_mdns_support(Link *l) { + _cleanup_free_ char *b = NULL; + int r; + + assert(l); + + r = sd_network_link_get_mdns(l->ifindex, &b); + if (r == -ENODATA) { + r = 0; + goto clear; + } + if (r < 0) + goto clear; + + l->mdns_support = resolve_support_from_string(b); + if (l->mdns_support < 0) { + r = -EINVAL; + goto clear; + } + + return 0; + +clear: + l->mdns_support = RESOLVE_SUPPORT_NO; + return r; +} + +void link_set_dnssec_mode(Link *l, DnssecMode mode) { + + assert(l); + + if (l->dnssec_mode == mode) + return; + + if ((l->dnssec_mode == _DNSSEC_MODE_INVALID) || + (l->dnssec_mode == DNSSEC_NO && mode != DNSSEC_NO) || + (l->dnssec_mode == DNSSEC_ALLOW_DOWNGRADE && mode == DNSSEC_YES)) { + + /* When switching from non-DNSSEC mode to DNSSEC mode, flush the cache. Also when switching from the + * allow-downgrade mode to full DNSSEC mode, flush it too. */ + if (l->unicast_scope) + dns_cache_flush(&l->unicast_scope->cache); + } + + l->dnssec_mode = mode; +} + +static int link_update_dnssec_mode(Link *l) { + _cleanup_free_ char *m = NULL; + DnssecMode mode; + int r; + + assert(l); + + r = sd_network_link_get_dnssec(l->ifindex, &m); + if (r == -ENODATA) { + r = 0; + goto clear; + } + if (r < 0) + goto clear; + + mode = dnssec_mode_from_string(m); + if (mode < 0) { + r = -EINVAL; + goto clear; + } + + link_set_dnssec_mode(l, mode); + + return 0; + +clear: + l->dnssec_mode = _DNSSEC_MODE_INVALID; + return r; +} + +static int link_update_dnssec_negative_trust_anchors(Link *l) { + _cleanup_strv_free_ char **ntas = NULL; + _cleanup_set_free_free_ Set *ns = NULL; + int r; + + assert(l); + + r = sd_network_link_get_dnssec_negative_trust_anchors(l->ifindex, &ntas); + if (r == -ENODATA) { + r = 0; + goto clear; + } + if (r < 0) + goto clear; + + ns = set_new(&dns_name_hash_ops); + if (!ns) + return -ENOMEM; + + r = set_put_strdupv(ns, ntas); + if (r < 0) + return r; + + set_free_free(l->dnssec_negative_trust_anchors); + l->dnssec_negative_trust_anchors = ns; + ns = NULL; + + return 0; + +clear: + l->dnssec_negative_trust_anchors = set_free_free(l->dnssec_negative_trust_anchors); + return r; +} + +static int link_update_search_domain_one(Link *l, const char *name, bool route_only) { + DnsSearchDomain *d; + int r; + + assert(l); + assert(name); + + r = dns_search_domain_find(l->search_domains, name, &d); + if (r < 0) + return r; + if (r > 0) + dns_search_domain_move_back_and_unmark(d); + else { + r = dns_search_domain_new(l->manager, &d, DNS_SEARCH_DOMAIN_LINK, l, name); + if (r < 0) + return r; + } + + d->route_only = route_only; + return 0; +} + +static int link_update_search_domains(Link *l) { + _cleanup_strv_free_ char **sdomains = NULL, **rdomains = NULL; + char **i; + int r, q; + + assert(l); + + r = sd_network_link_get_search_domains(l->ifindex, &sdomains); + if (r < 0 && r != -ENODATA) + goto clear; + + q = sd_network_link_get_route_domains(l->ifindex, &rdomains); + if (q < 0 && q != -ENODATA) { + r = q; + goto clear; + } + + if (r == -ENODATA && q == -ENODATA) { + /* networkd knows nothing about this interface, and that's fine. */ + r = 0; + goto clear; + } + + dns_search_domain_mark_all(l->search_domains); + + STRV_FOREACH(i, sdomains) { + r = link_update_search_domain_one(l, *i, false); + if (r < 0) + goto clear; + } + + STRV_FOREACH(i, rdomains) { + r = link_update_search_domain_one(l, *i, true); + if (r < 0) + goto clear; + } + + dns_search_domain_unlink_marked(l->search_domains); + return 0; + +clear: + dns_search_domain_unlink_all(l->search_domains); + return r; +} + +static int link_is_managed(Link *l) { + _cleanup_free_ char *state = NULL; + int r; + + assert(l); + + r = sd_network_link_get_setup_state(l->ifindex, &state); + if (r == -ENODATA) + return 0; + if (r < 0) + return r; + + return !STR_IN_SET(state, "pending", "unmanaged"); +} + +static void link_read_settings(Link *l) { + int r; + + assert(l); + + /* Read settings from networkd, except when networkd is not managing this interface. */ + + r = link_is_managed(l); + if (r < 0) { + log_warning_errno(r, "Failed to determine whether interface %s is managed: %m", l->name); + return; + } + if (r == 0) { + + /* If this link used to be managed, but is now unmanaged, flush all our settings — but only once. */ + if (l->is_managed) + link_flush_settings(l); + + l->is_managed = false; + return; + } + + l->is_managed = true; + + r = link_update_dns_servers(l); + if (r < 0) + log_warning_errno(r, "Failed to read DNS servers for interface %s, ignoring: %m", l->name); + + r = link_update_llmnr_support(l); + if (r < 0) + log_warning_errno(r, "Failed to read LLMNR support for interface %s, ignoring: %m", l->name); + + r = link_update_mdns_support(l); + if (r < 0) + log_warning_errno(r, "Failed to read mDNS support for interface %s, ignoring: %m", l->name); + + r = link_update_dnssec_mode(l); + if (r < 0) + log_warning_errno(r, "Failed to read DNSSEC mode for interface %s, ignoring: %m", l->name); + + r = link_update_dnssec_negative_trust_anchors(l); + if (r < 0) + log_warning_errno(r, "Failed to read DNSSEC negative trust anchors for interface %s, ignoring: %m", l->name); + + r = link_update_search_domains(l); + if (r < 0) + log_warning_errno(r, "Failed to read search domains for interface %s, ignoring: %m", l->name); +} + +int link_update(Link *l) { + assert(l); + + link_read_settings(l); + link_load_user(l); + link_allocate_scopes(l); + link_add_rrs(l, false); + + return 0; +} + +bool link_relevant(Link *l, int family, bool local_multicast) { + _cleanup_free_ char *state = NULL; + LinkAddress *a; + + assert(l); + + /* A link is relevant for local multicast traffic if it isn't a loopback or pointopoint device, has a link + * beat, can do multicast and has at least one link-local (or better) IP address. + * + * A link is relevant for non-multicast traffic if it isn't a loopback device, has a link beat, and has at + * least one routable address.*/ + + if (l->flags & (IFF_LOOPBACK|IFF_DORMANT)) + return false; + + if ((l->flags & (IFF_UP|IFF_LOWER_UP)) != (IFF_UP|IFF_LOWER_UP)) + return false; + + if (local_multicast) { + if (l->flags & IFF_POINTOPOINT) + return false; + + if ((l->flags & IFF_MULTICAST) != IFF_MULTICAST) + return false; + } + + /* Check kernel operstate + * https://www.kernel.org/doc/Documentation/networking/operstates.txt */ + if (!IN_SET(l->operstate, IF_OPER_UNKNOWN, IF_OPER_UP)) + return false; + + (void) sd_network_link_get_operational_state(l->ifindex, &state); + if (state && !STR_IN_SET(state, "unknown", "degraded", "routable")) + return false; + + LIST_FOREACH(addresses, a, l->addresses) + if ((family == AF_UNSPEC || a->family == family) && link_address_relevant(a, local_multicast)) + return true; + + return false; +} + +LinkAddress *link_find_address(Link *l, int family, const union in_addr_union *in_addr) { + LinkAddress *a; + + assert(l); + + LIST_FOREACH(addresses, a, l->addresses) + if (a->family == family && in_addr_equal(family, &a->in_addr, in_addr)) + return a; + + return NULL; +} + +DnsServer* link_set_dns_server(Link *l, DnsServer *s) { + assert(l); + + if (l->current_dns_server == s) + return s; + + if (s) + log_info("Switching to DNS server %s for interface %s.", dns_server_string(s), l->name); + + dns_server_unref(l->current_dns_server); + l->current_dns_server = dns_server_ref(s); + + if (l->unicast_scope) + dns_cache_flush(&l->unicast_scope->cache); + + return s; +} + +DnsServer *link_get_dns_server(Link *l) { + assert(l); + + if (!l->current_dns_server) + link_set_dns_server(l, l->dns_servers); + + return l->current_dns_server; +} + +void link_next_dns_server(Link *l) { + assert(l); + + if (!l->current_dns_server) + return; + + /* Change to the next one, but make sure to follow the linked + * list only if this server is actually still linked. */ + if (l->current_dns_server->linked && l->current_dns_server->servers_next) { + link_set_dns_server(l, l->current_dns_server->servers_next); + return; + } + + link_set_dns_server(l, l->dns_servers); +} + +DnssecMode link_get_dnssec_mode(Link *l) { + assert(l); + + if (l->dnssec_mode != _DNSSEC_MODE_INVALID) + return l->dnssec_mode; + + return manager_get_dnssec_mode(l->manager); +} + +bool link_dnssec_supported(Link *l) { + DnsServer *server; + + assert(l); + + if (link_get_dnssec_mode(l) == DNSSEC_NO) + return false; + + server = link_get_dns_server(l); + if (server) + return dns_server_dnssec_supported(server); + + return true; +} + +int link_address_new(Link *l, LinkAddress **ret, int family, const union in_addr_union *in_addr) { + LinkAddress *a; + + assert(l); + assert(in_addr); + + a = new0(LinkAddress, 1); + if (!a) + return -ENOMEM; + + a->family = family; + a->in_addr = *in_addr; + + a->link = l; + LIST_PREPEND(addresses, l->addresses, a); + + if (ret) + *ret = a; + + return 0; +} + +LinkAddress *link_address_free(LinkAddress *a) { + if (!a) + return NULL; + + if (a->link) { + LIST_REMOVE(addresses, a->link->addresses, a); + + if (a->llmnr_address_rr) { + if (a->family == AF_INET && a->link->llmnr_ipv4_scope) + dns_zone_remove_rr(&a->link->llmnr_ipv4_scope->zone, a->llmnr_address_rr); + else if (a->family == AF_INET6 && a->link->llmnr_ipv6_scope) + dns_zone_remove_rr(&a->link->llmnr_ipv6_scope->zone, a->llmnr_address_rr); + } + + if (a->llmnr_ptr_rr) { + if (a->family == AF_INET && a->link->llmnr_ipv4_scope) + dns_zone_remove_rr(&a->link->llmnr_ipv4_scope->zone, a->llmnr_ptr_rr); + else if (a->family == AF_INET6 && a->link->llmnr_ipv6_scope) + dns_zone_remove_rr(&a->link->llmnr_ipv6_scope->zone, a->llmnr_ptr_rr); + } + } + + dns_resource_record_unref(a->llmnr_address_rr); + dns_resource_record_unref(a->llmnr_ptr_rr); + + return mfree(a); +} + +void link_address_add_rrs(LinkAddress *a, bool force_remove) { + int r; + + assert(a); + + if (a->family == AF_INET) { + + if (!force_remove && + link_address_relevant(a, true) && + a->link->llmnr_ipv4_scope && + a->link->llmnr_support == RESOLVE_SUPPORT_YES && + a->link->manager->llmnr_support == RESOLVE_SUPPORT_YES) { + + if (!a->link->manager->llmnr_host_ipv4_key) { + a->link->manager->llmnr_host_ipv4_key = dns_resource_key_new(DNS_CLASS_IN, DNS_TYPE_A, a->link->manager->llmnr_hostname); + if (!a->link->manager->llmnr_host_ipv4_key) { + r = -ENOMEM; + goto fail; + } + } + + if (!a->llmnr_address_rr) { + a->llmnr_address_rr = dns_resource_record_new(a->link->manager->llmnr_host_ipv4_key); + if (!a->llmnr_address_rr) { + r = -ENOMEM; + goto fail; + } + + a->llmnr_address_rr->a.in_addr = a->in_addr.in; + a->llmnr_address_rr->ttl = LLMNR_DEFAULT_TTL; + } + + if (!a->llmnr_ptr_rr) { + r = dns_resource_record_new_reverse(&a->llmnr_ptr_rr, a->family, &a->in_addr, a->link->manager->llmnr_hostname); + if (r < 0) + goto fail; + + a->llmnr_ptr_rr->ttl = LLMNR_DEFAULT_TTL; + } + + r = dns_zone_put(&a->link->llmnr_ipv4_scope->zone, a->link->llmnr_ipv4_scope, a->llmnr_address_rr, true); + if (r < 0) + log_warning_errno(r, "Failed to add A record to LLMNR zone: %m"); + + r = dns_zone_put(&a->link->llmnr_ipv4_scope->zone, a->link->llmnr_ipv4_scope, a->llmnr_ptr_rr, false); + if (r < 0) + log_warning_errno(r, "Failed to add IPv6 PTR record to LLMNR zone: %m"); + } else { + if (a->llmnr_address_rr) { + if (a->link->llmnr_ipv4_scope) + dns_zone_remove_rr(&a->link->llmnr_ipv4_scope->zone, a->llmnr_address_rr); + a->llmnr_address_rr = dns_resource_record_unref(a->llmnr_address_rr); + } + + if (a->llmnr_ptr_rr) { + if (a->link->llmnr_ipv4_scope) + dns_zone_remove_rr(&a->link->llmnr_ipv4_scope->zone, a->llmnr_ptr_rr); + a->llmnr_ptr_rr = dns_resource_record_unref(a->llmnr_ptr_rr); + } + } + } + + if (a->family == AF_INET6) { + + if (!force_remove && + link_address_relevant(a, true) && + a->link->llmnr_ipv6_scope && + a->link->llmnr_support == RESOLVE_SUPPORT_YES && + a->link->manager->llmnr_support == RESOLVE_SUPPORT_YES) { + + if (!a->link->manager->llmnr_host_ipv6_key) { + a->link->manager->llmnr_host_ipv6_key = dns_resource_key_new(DNS_CLASS_IN, DNS_TYPE_AAAA, a->link->manager->llmnr_hostname); + if (!a->link->manager->llmnr_host_ipv6_key) { + r = -ENOMEM; + goto fail; + } + } + + if (!a->llmnr_address_rr) { + a->llmnr_address_rr = dns_resource_record_new(a->link->manager->llmnr_host_ipv6_key); + if (!a->llmnr_address_rr) { + r = -ENOMEM; + goto fail; + } + + a->llmnr_address_rr->aaaa.in6_addr = a->in_addr.in6; + a->llmnr_address_rr->ttl = LLMNR_DEFAULT_TTL; + } + + if (!a->llmnr_ptr_rr) { + r = dns_resource_record_new_reverse(&a->llmnr_ptr_rr, a->family, &a->in_addr, a->link->manager->llmnr_hostname); + if (r < 0) + goto fail; + + a->llmnr_ptr_rr->ttl = LLMNR_DEFAULT_TTL; + } + + r = dns_zone_put(&a->link->llmnr_ipv6_scope->zone, a->link->llmnr_ipv6_scope, a->llmnr_address_rr, true); + if (r < 0) + log_warning_errno(r, "Failed to add AAAA record to LLMNR zone: %m"); + + r = dns_zone_put(&a->link->llmnr_ipv6_scope->zone, a->link->llmnr_ipv6_scope, a->llmnr_ptr_rr, false); + if (r < 0) + log_warning_errno(r, "Failed to add IPv6 PTR record to LLMNR zone: %m"); + } else { + if (a->llmnr_address_rr) { + if (a->link->llmnr_ipv6_scope) + dns_zone_remove_rr(&a->link->llmnr_ipv6_scope->zone, a->llmnr_address_rr); + a->llmnr_address_rr = dns_resource_record_unref(a->llmnr_address_rr); + } + + if (a->llmnr_ptr_rr) { + if (a->link->llmnr_ipv6_scope) + dns_zone_remove_rr(&a->link->llmnr_ipv6_scope->zone, a->llmnr_ptr_rr); + a->llmnr_ptr_rr = dns_resource_record_unref(a->llmnr_ptr_rr); + } + } + } + + return; + +fail: + log_debug_errno(r, "Failed to update address RRs: %m"); +} + +int link_address_update_rtnl(LinkAddress *a, sd_netlink_message *m) { + int r; + assert(a); + assert(m); + + r = sd_rtnl_message_addr_get_flags(m, &a->flags); + if (r < 0) + return r; + + sd_rtnl_message_addr_get_scope(m, &a->scope); + + link_allocate_scopes(a->link); + link_add_rrs(a->link, false); + + return 0; +} + +bool link_address_relevant(LinkAddress *a, bool local_multicast) { + assert(a); + + if (a->flags & (IFA_F_DEPRECATED|IFA_F_TENTATIVE)) + return false; + + if (a->scope >= (local_multicast ? RT_SCOPE_HOST : RT_SCOPE_LINK)) + return false; + + return true; +} + +static bool link_needs_save(Link *l) { + assert(l); + + /* Returns true if any of the settings where set different from the default */ + + if (l->is_managed) + return false; + + if (l->llmnr_support != RESOLVE_SUPPORT_YES || + l->mdns_support != RESOLVE_SUPPORT_NO || + l->dnssec_mode != _DNSSEC_MODE_INVALID) + return true; + + if (l->dns_servers || + l->search_domains) + return true; + + if (!set_isempty(l->dnssec_negative_trust_anchors)) + return true; + + return false; +} + +int link_save_user(Link *l) { + _cleanup_free_ char *temp_path = NULL; + _cleanup_fclose_ FILE *f = NULL; + const char *v; + int r; + + assert(l); + assert(l->state_file); + + if (!link_needs_save(l)) { + (void) unlink(l->state_file); + return 0; + } + + r = mkdir_parents(l->state_file, 0700); + if (r < 0) + goto fail; + + r = fopen_temporary(l->state_file, &f, &temp_path); + if (r < 0) + goto fail; + + fputs("# This is private data. Do not parse.\n", f); + + v = resolve_support_to_string(l->llmnr_support); + if (v) + fprintf(f, "LLMNR=%s\n", v); + + v = resolve_support_to_string(l->mdns_support); + if (v) + fprintf(f, "MDNS=%s\n", v); + + v = dnssec_mode_to_string(l->dnssec_mode); + if (v) + fprintf(f, "DNSSEC=%s\n", v); + + if (l->dns_servers) { + DnsServer *server; + + fputs("SERVERS=", f); + LIST_FOREACH(servers, server, l->dns_servers) { + + if (server != l->dns_servers) + fputc(' ', f); + + v = dns_server_string(server); + if (!v) { + r = -ENOMEM; + goto fail; + } + + fputs(v, f); + } + fputc('\n', f); + } + + if (l->search_domains) { + DnsSearchDomain *domain; + + fputs("DOMAINS=", f); + LIST_FOREACH(domains, domain, l->search_domains) { + + if (domain != l->search_domains) + fputc(' ', f); + + if (domain->route_only) + fputc('~', f); + + fputs(DNS_SEARCH_DOMAIN_NAME(domain), f); + } + fputc('\n', f); + } + + if (!set_isempty(l->dnssec_negative_trust_anchors)) { + bool space = false; + Iterator i; + char *nta; + + fputs("NTAS=", f); + SET_FOREACH(nta, l->dnssec_negative_trust_anchors, i) { + + if (space) + fputc(' ', f); + + fputs(nta, f); + space = true; + } + fputc('\n', f); + } + + r = fflush_and_check(f); + if (r < 0) + goto fail; + + if (rename(temp_path, l->state_file) < 0) { + r = -errno; + goto fail; + } + + return 0; + +fail: + (void) unlink(l->state_file); + + if (temp_path) + (void) unlink(temp_path); + + return log_error_errno(r, "Failed to save link data %s: %m", l->state_file); +} + +int link_load_user(Link *l) { + _cleanup_free_ char + *llmnr = NULL, + *mdns = NULL, + *dnssec = NULL, + *servers = NULL, + *domains = NULL, + *ntas = NULL; + + ResolveSupport s; + int r; + + assert(l); + assert(l->state_file); + + /* Try to load only a single time */ + if (l->loaded) + return 0; + l->loaded = true; + + if (l->is_managed) + return 0; /* if the device is managed, then networkd is our configuration source, not the bus API */ + + r = parse_env_file(l->state_file, NEWLINE, + "LLMNR", &llmnr, + "MDNS", &mdns, + "DNSSEC", &dnssec, + "SERVERS", &servers, + "DOMAINS", &domains, + "NTAS", &ntas, + NULL); + if (r == -ENOENT) + return 0; + if (r < 0) + goto fail; + + link_flush_settings(l); + + /* If we can't recognize the LLMNR or MDNS setting we don't override the default */ + s = resolve_support_from_string(llmnr); + if (s >= 0) + l->llmnr_support = s; + + s = resolve_support_from_string(mdns); + if (s >= 0) + l->mdns_support = s; + + /* If we can't recognize the DNSSEC setting, then set it to invalid, so that the daemon default is used. */ + l->dnssec_mode = dnssec_mode_from_string(dnssec); + + if (servers) { + const char *p = servers; + + for (;;) { + _cleanup_free_ char *word = NULL; + + r = extract_first_word(&p, &word, NULL, 0); + if (r < 0) + goto fail; + if (r == 0) + break; + + r = link_update_dns_server_one(l, word); + if (r < 0) { + log_debug_errno(r, "Failed to load DNS server '%s', ignoring: %m", word); + continue; + } + } + } + + if (domains) { + const char *p = domains; + + for (;;) { + _cleanup_free_ char *word = NULL; + const char *n; + bool is_route; + + r = extract_first_word(&p, &word, NULL, 0); + if (r < 0) + goto fail; + if (r == 0) + break; + + is_route = word[0] == '~'; + n = is_route ? word + 1 : word; + + r = link_update_search_domain_one(l, n, is_route); + if (r < 0) { + log_debug_errno(r, "Failed to load search domain '%s', ignoring: %m", word); + continue; + } + } + } + + if (ntas) { + _cleanup_set_free_free_ Set *ns = NULL; + + ns = set_new(&dns_name_hash_ops); + if (!ns) { + r = -ENOMEM; + goto fail; + } + + r = set_put_strsplit(ns, ntas, NULL, 0); + if (r < 0) + goto fail; + + l->dnssec_negative_trust_anchors = ns; + ns = NULL; + } + + return 0; + +fail: + return log_error_errno(r, "Failed to load link data %s: %m", l->state_file); +} + +void link_remove_user(Link *l) { + assert(l); + assert(l->state_file); + + (void) unlink(l->state_file); +} diff --git a/src/grp-resolve/systemd-resolved/resolved-link.h b/src/grp-resolve/systemd-resolved/resolved-link.h new file mode 100644 index 0000000000..271309914f --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-link.h @@ -0,0 +1,119 @@ +#pragma once + +/*** + This file is part of systemd. + + Copyright 2014 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include <net/if.h> + +#include "basic-dns/resolved-dns-rr.h" +#include "systemd-basic/in-addr-util.h" +#include "systemd-basic/ratelimit.h" +#include "systemd-shared/resolve-util.h" + +typedef struct Link Link; +typedef struct LinkAddress LinkAddress; + +#include "resolved-dns-scope.h" +#include "resolved-dns-search-domain.h" +#include "resolved-dns-server.h" +#include "resolved-manager.h" + +#define LINK_SEARCH_DOMAINS_MAX 32 +#define LINK_DNS_SERVERS_MAX 32 + +struct LinkAddress { + Link *link; + + int family; + union in_addr_union in_addr; + + unsigned char flags, scope; + + DnsResourceRecord *llmnr_address_rr; + DnsResourceRecord *llmnr_ptr_rr; + + LIST_FIELDS(LinkAddress, addresses); +}; + +struct Link { + Manager *manager; + + int ifindex; + unsigned flags; + + LIST_HEAD(LinkAddress, addresses); + + LIST_HEAD(DnsServer, dns_servers); + DnsServer *current_dns_server; + unsigned n_dns_servers; + + LIST_HEAD(DnsSearchDomain, search_domains); + unsigned n_search_domains; + + ResolveSupport llmnr_support; + ResolveSupport mdns_support; + DnssecMode dnssec_mode; + Set *dnssec_negative_trust_anchors; + + DnsScope *unicast_scope; + DnsScope *llmnr_ipv4_scope; + DnsScope *llmnr_ipv6_scope; + DnsScope *mdns_ipv4_scope; + DnsScope *mdns_ipv6_scope; + + bool is_managed; + + char name[IF_NAMESIZE]; + uint32_t mtu; + uint8_t operstate; + + bool loaded; + char *state_file; +}; + +int link_new(Manager *m, Link **ret, int ifindex); +Link *link_free(Link *l); +int link_process_rtnl(Link *l, sd_netlink_message *m); +int link_update(Link *l); +bool link_relevant(Link *l, int family, bool local_multicast); +LinkAddress* link_find_address(Link *l, int family, const union in_addr_union *in_addr); +void link_add_rrs(Link *l, bool force_remove); + +void link_flush_settings(Link *l); +void link_set_dnssec_mode(Link *l, DnssecMode mode); +void link_allocate_scopes(Link *l); + +DnsServer* link_set_dns_server(Link *l, DnsServer *s); +DnsServer* link_get_dns_server(Link *l); +void link_next_dns_server(Link *l); + +DnssecMode link_get_dnssec_mode(Link *l); +bool link_dnssec_supported(Link *l); + +int link_save_user(Link *l); +int link_load_user(Link *l); +void link_remove_user(Link *l); + +int link_address_new(Link *l, LinkAddress **ret, int family, const union in_addr_union *in_addr); +LinkAddress *link_address_free(LinkAddress *a); +int link_address_update_rtnl(LinkAddress *a, sd_netlink_message *m); +bool link_address_relevant(LinkAddress *l, bool local_multicast); +void link_address_add_rrs(LinkAddress *a, bool force_remove); + +DEFINE_TRIVIAL_CLEANUP_FUNC(Link*, link_free); diff --git a/src/grp-resolve/systemd-resolved/resolved-llmnr.c b/src/grp-resolve/systemd-resolved/resolved-llmnr.c new file mode 100644 index 0000000000..2a22f20790 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-llmnr.c @@ -0,0 +1,472 @@ +/*** + This file is part of systemd. + + Copyright 2014 Tom Gundersen <teg@jklm.no> + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. + ***/ + +#include <netinet/in.h> +#include <resolv.h> + +#include "systemd-basic/fd-util.h" + +#include "resolved-llmnr.h" +#include "resolved-manager.h" + +void manager_llmnr_stop(Manager *m) { + assert(m); + + m->llmnr_ipv4_udp_event_source = sd_event_source_unref(m->llmnr_ipv4_udp_event_source); + m->llmnr_ipv4_udp_fd = safe_close(m->llmnr_ipv4_udp_fd); + + m->llmnr_ipv6_udp_event_source = sd_event_source_unref(m->llmnr_ipv6_udp_event_source); + m->llmnr_ipv6_udp_fd = safe_close(m->llmnr_ipv6_udp_fd); + + m->llmnr_ipv4_tcp_event_source = sd_event_source_unref(m->llmnr_ipv4_tcp_event_source); + m->llmnr_ipv4_tcp_fd = safe_close(m->llmnr_ipv4_tcp_fd); + + m->llmnr_ipv6_tcp_event_source = sd_event_source_unref(m->llmnr_ipv6_tcp_event_source); + m->llmnr_ipv6_tcp_fd = safe_close(m->llmnr_ipv6_tcp_fd); +} + +int manager_llmnr_start(Manager *m) { + int r; + + assert(m); + + if (m->llmnr_support == RESOLVE_SUPPORT_NO) + return 0; + + r = manager_llmnr_ipv4_udp_fd(m); + if (r == -EADDRINUSE) + goto eaddrinuse; + if (r < 0) + return r; + + r = manager_llmnr_ipv4_tcp_fd(m); + if (r == -EADDRINUSE) + goto eaddrinuse; + if (r < 0) + return r; + + if (socket_ipv6_is_supported()) { + r = manager_llmnr_ipv6_udp_fd(m); + if (r == -EADDRINUSE) + goto eaddrinuse; + if (r < 0) + return r; + + r = manager_llmnr_ipv6_tcp_fd(m); + if (r == -EADDRINUSE) + goto eaddrinuse; + if (r < 0) + return r; + } + + return 0; + +eaddrinuse: + log_warning("There appears to be another LLMNR responder running. Turning off LLMNR support."); + m->llmnr_support = RESOLVE_SUPPORT_NO; + manager_llmnr_stop(m); + + return 0; +} + +static int on_llmnr_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) { + _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; + DnsTransaction *t = NULL; + Manager *m = userdata; + DnsScope *scope; + int r; + + assert(s); + assert(fd >= 0); + assert(m); + + r = manager_recv(m, fd, DNS_PROTOCOL_LLMNR, &p); + if (r <= 0) + return r; + + scope = manager_find_scope(m, p); + if (!scope) + log_warning("Got LLMNR UDP packet on unknown scope. Ignoring."); + else if (dns_packet_validate_reply(p) > 0) { + log_debug("Got LLMNR UDP reply packet for id %u", DNS_PACKET_ID(p)); + + dns_scope_check_conflicts(scope, p); + + t = hashmap_get(m->dns_transactions, UINT_TO_PTR(DNS_PACKET_ID(p))); + if (t) + dns_transaction_process_reply(t, p); + + } else if (dns_packet_validate_query(p) > 0) { + log_debug("Got LLMNR UDP query packet for id %u", DNS_PACKET_ID(p)); + + dns_scope_process_query(scope, NULL, p); + } else + log_debug("Invalid LLMNR UDP packet, ignoring."); + + return 0; +} + +int manager_llmnr_ipv4_udp_fd(Manager *m) { + union sockaddr_union sa = { + .in.sin_family = AF_INET, + .in.sin_port = htobe16(LLMNR_PORT), + }; + static const int one = 1, pmtu = IP_PMTUDISC_DONT, ttl = 255; + int r; + + assert(m); + + if (m->llmnr_ipv4_udp_fd >= 0) + return m->llmnr_ipv4_udp_fd; + + m->llmnr_ipv4_udp_fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); + if (m->llmnr_ipv4_udp_fd < 0) + return -errno; + + /* RFC 4795, section 2.5 recommends setting the TTL of UDP packets to 255. */ + r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_TTL, &ttl, sizeof(ttl)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_MULTICAST_LOOP, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->llmnr_ipv4_udp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_RECVTTL, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + /* Disable Don't-Fragment bit in the IP header */ + r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_MTU_DISCOVER, &pmtu, sizeof(pmtu)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = bind(m->llmnr_ipv4_udp_fd, &sa.sa, sizeof(sa.in)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = sd_event_add_io(m->event, &m->llmnr_ipv4_udp_event_source, m->llmnr_ipv4_udp_fd, EPOLLIN, on_llmnr_packet, m); + if (r < 0) + goto fail; + + (void) sd_event_source_set_description(m->llmnr_ipv4_udp_event_source, "llmnr-ipv4-udp"); + + return m->llmnr_ipv4_udp_fd; + +fail: + m->llmnr_ipv4_udp_fd = safe_close(m->llmnr_ipv4_udp_fd); + return r; +} + +int manager_llmnr_ipv6_udp_fd(Manager *m) { + union sockaddr_union sa = { + .in6.sin6_family = AF_INET6, + .in6.sin6_port = htobe16(LLMNR_PORT), + }; + static const int one = 1, ttl = 255; + int r; + + assert(m); + + if (m->llmnr_ipv6_udp_fd >= 0) + return m->llmnr_ipv6_udp_fd; + + m->llmnr_ipv6_udp_fd = socket(AF_INET6, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); + if (m->llmnr_ipv6_udp_fd < 0) + return -errno; + + r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &ttl, sizeof(ttl)); + if (r < 0) { + r = -errno; + goto fail; + } + + /* RFC 4795, section 2.5 recommends setting the TTL of UDP packets to 255. */ + r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &ttl, sizeof(ttl)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->llmnr_ipv6_udp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = bind(m->llmnr_ipv6_udp_fd, &sa.sa, sizeof(sa.in6)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = sd_event_add_io(m->event, &m->llmnr_ipv6_udp_event_source, m->llmnr_ipv6_udp_fd, EPOLLIN, on_llmnr_packet, m); + if (r < 0) + goto fail; + + (void) sd_event_source_set_description(m->llmnr_ipv6_udp_event_source, "llmnr-ipv6-udp"); + + return m->llmnr_ipv6_udp_fd; + +fail: + m->llmnr_ipv6_udp_fd = safe_close(m->llmnr_ipv6_udp_fd); + return r; +} + +static int on_llmnr_stream_packet(DnsStream *s) { + DnsScope *scope; + + assert(s); + assert(s->read_packet); + + scope = manager_find_scope(s->manager, s->read_packet); + if (!scope) + log_warning("Got LLMNR TCP packet on unknown scope. Ignoring."); + else if (dns_packet_validate_query(s->read_packet) > 0) { + log_debug("Got LLMNR TCP query packet for id %u", DNS_PACKET_ID(s->read_packet)); + + dns_scope_process_query(scope, s, s->read_packet); + } else + log_debug("Invalid LLMNR TCP packet, ignoring."); + + dns_stream_unref(s); + return 0; +} + +static int on_llmnr_stream(sd_event_source *s, int fd, uint32_t revents, void *userdata) { + DnsStream *stream; + Manager *m = userdata; + int cfd, r; + + cfd = accept4(fd, NULL, NULL, SOCK_NONBLOCK|SOCK_CLOEXEC); + if (cfd < 0) { + if (errno == EAGAIN || errno == EINTR) + return 0; + + return -errno; + } + + r = dns_stream_new(m, &stream, DNS_PROTOCOL_LLMNR, cfd); + if (r < 0) { + safe_close(cfd); + return r; + } + + stream->on_packet = on_llmnr_stream_packet; + return 0; +} + +int manager_llmnr_ipv4_tcp_fd(Manager *m) { + union sockaddr_union sa = { + .in.sin_family = AF_INET, + .in.sin_port = htobe16(LLMNR_PORT), + }; + static const int one = 1, pmtu = IP_PMTUDISC_DONT; + int r; + + assert(m); + + if (m->llmnr_ipv4_tcp_fd >= 0) + return m->llmnr_ipv4_tcp_fd; + + m->llmnr_ipv4_tcp_fd = socket(AF_INET, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); + if (m->llmnr_ipv4_tcp_fd < 0) + return -errno; + + /* RFC 4795, section 2.5. requires setting the TTL of TCP streams to 1 */ + r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_TTL, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->llmnr_ipv4_tcp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_RECVTTL, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + /* Disable Don't-Fragment bit in the IP header */ + r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_MTU_DISCOVER, &pmtu, sizeof(pmtu)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = bind(m->llmnr_ipv4_tcp_fd, &sa.sa, sizeof(sa.in)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = listen(m->llmnr_ipv4_tcp_fd, SOMAXCONN); + if (r < 0) { + r = -errno; + goto fail; + } + + r = sd_event_add_io(m->event, &m->llmnr_ipv4_tcp_event_source, m->llmnr_ipv4_tcp_fd, EPOLLIN, on_llmnr_stream, m); + if (r < 0) + goto fail; + + (void) sd_event_source_set_description(m->llmnr_ipv4_tcp_event_source, "llmnr-ipv4-tcp"); + + return m->llmnr_ipv4_tcp_fd; + +fail: + m->llmnr_ipv4_tcp_fd = safe_close(m->llmnr_ipv4_tcp_fd); + return r; +} + +int manager_llmnr_ipv6_tcp_fd(Manager *m) { + union sockaddr_union sa = { + .in6.sin6_family = AF_INET6, + .in6.sin6_port = htobe16(LLMNR_PORT), + }; + static const int one = 1; + int r; + + assert(m); + + if (m->llmnr_ipv6_tcp_fd >= 0) + return m->llmnr_ipv6_tcp_fd; + + m->llmnr_ipv6_tcp_fd = socket(AF_INET6, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); + if (m->llmnr_ipv6_tcp_fd < 0) + return -errno; + + /* RFC 4795, section 2.5. requires setting the TTL of TCP streams to 1 */ + r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->llmnr_ipv6_tcp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = bind(m->llmnr_ipv6_tcp_fd, &sa.sa, sizeof(sa.in6)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = listen(m->llmnr_ipv6_tcp_fd, SOMAXCONN); + if (r < 0) { + r = -errno; + goto fail; + } + + r = sd_event_add_io(m->event, &m->llmnr_ipv6_tcp_event_source, m->llmnr_ipv6_tcp_fd, EPOLLIN, on_llmnr_stream, m); + if (r < 0) + goto fail; + + (void) sd_event_source_set_description(m->llmnr_ipv6_tcp_event_source, "llmnr-ipv6-tcp"); + + return m->llmnr_ipv6_tcp_fd; + +fail: + m->llmnr_ipv6_tcp_fd = safe_close(m->llmnr_ipv6_tcp_fd); + return r; +} diff --git a/src/grp-resolve/systemd-resolved/resolved-llmnr.h b/src/grp-resolve/systemd-resolved/resolved-llmnr.h new file mode 100644 index 0000000000..8133582fa7 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-llmnr.h @@ -0,0 +1,32 @@ +#pragma once + +/*** + This file is part of systemd. + + Copyright 2014 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include "resolved-manager.h" + +#define LLMNR_PORT 5355 + +int manager_llmnr_ipv4_udp_fd(Manager *m); +int manager_llmnr_ipv6_udp_fd(Manager *m); +int manager_llmnr_ipv4_tcp_fd(Manager *m); +int manager_llmnr_ipv6_tcp_fd(Manager *m); + +void manager_llmnr_stop(Manager *m); +int manager_llmnr_start(Manager *m); diff --git a/src/grp-resolve/systemd-resolved/resolved-manager.c b/src/grp-resolve/systemd-resolved/resolved-manager.c new file mode 100644 index 0000000000..67bbe30f13 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-manager.c @@ -0,0 +1,1378 @@ +/*** + This file is part of systemd. + + Copyright 2014 Tom Gundersen <teg@jklm.no> + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. + ***/ + +#include <netinet/in.h> +#include <poll.h> +#include <sys/ioctl.h> + +#include "sd-netlink/netlink-util.h" +#include "systemd-basic/af-list.h" +#include "systemd-basic/alloc-util.h" +#include "systemd-basic/dirent-util.h" +#include "systemd-basic/fd-util.h" +#include "systemd-basic/fileio-label.h" +#include "systemd-basic/hostname-util.h" +#include "systemd-basic/io-util.h" +#include "systemd-basic/ordered-set.h" +#include "systemd-basic/parse-util.h" +#include "systemd-basic/random-util.h" +#include "systemd-basic/socket-util.h" +#include "systemd-basic/string-table.h" +#include "systemd-basic/string-util.h" +#include "systemd-basic/utf8.h" +#include "systemd-network/network-internal.h" +#include "systemd-shared/dns-domain.h" + +#include "resolved-bus.h" +#include "resolved-conf.h" +#include "resolved-dns-stub.h" +#include "resolved-etc-hosts.h" +#include "resolved-llmnr.h" +#include "resolved-manager.h" +#include "resolved-mdns.h" +#include "resolved-resolv-conf.h" + +#define SEND_TIMEOUT_USEC (200 * USEC_PER_MSEC) + +static int manager_process_link(sd_netlink *rtnl, sd_netlink_message *mm, void *userdata) { + Manager *m = userdata; + uint16_t type; + Link *l; + int ifindex, r; + + assert(rtnl); + assert(m); + assert(mm); + + r = sd_netlink_message_get_type(mm, &type); + if (r < 0) + goto fail; + + r = sd_rtnl_message_link_get_ifindex(mm, &ifindex); + if (r < 0) + goto fail; + + l = hashmap_get(m->links, INT_TO_PTR(ifindex)); + + switch (type) { + + case RTM_NEWLINK:{ + bool is_new = !l; + + if (!l) { + r = link_new(m, &l, ifindex); + if (r < 0) + goto fail; + } + + r = link_process_rtnl(l, mm); + if (r < 0) + goto fail; + + r = link_update(l); + if (r < 0) + goto fail; + + if (is_new) + log_debug("Found new link %i/%s", ifindex, l->name); + + break; + } + + case RTM_DELLINK: + if (l) { + log_debug("Removing link %i/%s", l->ifindex, l->name); + link_remove_user(l); + link_free(l); + } + + break; + } + + return 0; + +fail: + log_warning_errno(r, "Failed to process RTNL link message: %m"); + return 0; +} + +static int manager_process_address(sd_netlink *rtnl, sd_netlink_message *mm, void *userdata) { + Manager *m = userdata; + union in_addr_union address; + uint16_t type; + int r, ifindex, family; + LinkAddress *a; + Link *l; + + assert(rtnl); + assert(mm); + assert(m); + + r = sd_netlink_message_get_type(mm, &type); + if (r < 0) + goto fail; + + r = sd_rtnl_message_addr_get_ifindex(mm, &ifindex); + if (r < 0) + goto fail; + + l = hashmap_get(m->links, INT_TO_PTR(ifindex)); + if (!l) + return 0; + + r = sd_rtnl_message_addr_get_family(mm, &family); + if (r < 0) + goto fail; + + switch (family) { + + case AF_INET: + r = sd_netlink_message_read_in_addr(mm, IFA_LOCAL, &address.in); + if (r < 0) { + r = sd_netlink_message_read_in_addr(mm, IFA_ADDRESS, &address.in); + if (r < 0) + goto fail; + } + + break; + + case AF_INET6: + r = sd_netlink_message_read_in6_addr(mm, IFA_LOCAL, &address.in6); + if (r < 0) { + r = sd_netlink_message_read_in6_addr(mm, IFA_ADDRESS, &address.in6); + if (r < 0) + goto fail; + } + + break; + + default: + return 0; + } + + a = link_find_address(l, family, &address); + + switch (type) { + + case RTM_NEWADDR: + + if (!a) { + r = link_address_new(l, &a, family, &address); + if (r < 0) + return r; + } + + r = link_address_update_rtnl(a, mm); + if (r < 0) + return r; + + break; + + case RTM_DELADDR: + link_address_free(a); + break; + } + + return 0; + +fail: + log_warning_errno(r, "Failed to process RTNL address message: %m"); + return 0; +} + +static int manager_rtnl_listen(Manager *m) { + _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req = NULL, *reply = NULL; + sd_netlink_message *i; + int r; + + assert(m); + + /* First, subscribe to interfaces coming and going */ + r = sd_netlink_open(&m->rtnl); + if (r < 0) + return r; + + r = sd_netlink_attach_event(m->rtnl, m->event, SD_EVENT_PRIORITY_IMPORTANT); + if (r < 0) + return r; + + r = sd_netlink_add_match(m->rtnl, RTM_NEWLINK, manager_process_link, m); + if (r < 0) + return r; + + r = sd_netlink_add_match(m->rtnl, RTM_DELLINK, manager_process_link, m); + if (r < 0) + return r; + + r = sd_netlink_add_match(m->rtnl, RTM_NEWADDR, manager_process_address, m); + if (r < 0) + return r; + + r = sd_netlink_add_match(m->rtnl, RTM_DELADDR, manager_process_address, m); + if (r < 0) + return r; + + /* Then, enumerate all links */ + r = sd_rtnl_message_new_link(m->rtnl, &req, RTM_GETLINK, 0); + if (r < 0) + return r; + + r = sd_netlink_message_request_dump(req, true); + if (r < 0) + return r; + + r = sd_netlink_call(m->rtnl, req, 0, &reply); + if (r < 0) + return r; + + for (i = reply; i; i = sd_netlink_message_next(i)) { + r = manager_process_link(m->rtnl, i, m); + if (r < 0) + return r; + } + + req = sd_netlink_message_unref(req); + reply = sd_netlink_message_unref(reply); + + /* Finally, enumerate all addresses, too */ + r = sd_rtnl_message_new_addr(m->rtnl, &req, RTM_GETADDR, 0, AF_UNSPEC); + if (r < 0) + return r; + + r = sd_netlink_message_request_dump(req, true); + if (r < 0) + return r; + + r = sd_netlink_call(m->rtnl, req, 0, &reply); + if (r < 0) + return r; + + for (i = reply; i; i = sd_netlink_message_next(i)) { + r = manager_process_address(m->rtnl, i, m); + if (r < 0) + return r; + } + + return r; +} + +static int on_network_event(sd_event_source *s, int fd, uint32_t revents, void *userdata) { + Manager *m = userdata; + Iterator i; + Link *l; + int r; + + assert(m); + + sd_network_monitor_flush(m->network_monitor); + + HASHMAP_FOREACH(l, m->links, i) { + r = link_update(l); + if (r < 0) + log_warning_errno(r, "Failed to update monitor information for %i: %m", l->ifindex); + } + + (void) manager_write_resolv_conf(m); + + return 0; +} + +static int manager_network_monitor_listen(Manager *m) { + int r, fd, events; + + assert(m); + + r = sd_network_monitor_new(&m->network_monitor, NULL); + if (r < 0) + return r; + + fd = sd_network_monitor_get_fd(m->network_monitor); + if (fd < 0) + return fd; + + events = sd_network_monitor_get_events(m->network_monitor); + if (events < 0) + return events; + + r = sd_event_add_io(m->event, &m->network_event_source, fd, events, &on_network_event, m); + if (r < 0) + return r; + + r = sd_event_source_set_priority(m->network_event_source, SD_EVENT_PRIORITY_IMPORTANT+5); + if (r < 0) + return r; + + (void) sd_event_source_set_description(m->network_event_source, "network-monitor"); + + return 0; +} + +static int determine_hostname(char **llmnr_hostname, char **mdns_hostname) { + _cleanup_free_ char *h = NULL, *n = NULL; + char label[DNS_LABEL_MAX]; + const char *p; + int r, k; + + assert(llmnr_hostname); + assert(mdns_hostname); + + /* Extract and normalize the first label of the locally + * configured hostname, and check it's not "localhost". */ + + h = gethostname_malloc(); + if (!h) + return log_oom(); + + p = h; + r = dns_label_unescape(&p, label, sizeof(label)); + if (r < 0) + return log_error_errno(r, "Failed to unescape host name: %m"); + if (r == 0) { + log_error("Couldn't find a single label in hosntame."); + return -EINVAL; + } + + k = dns_label_undo_idna(label, r, label, sizeof(label)); + if (k < 0) + return log_error_errno(k, "Failed to undo IDNA: %m"); + if (k > 0) + r = k; + + if (!utf8_is_valid(label)) { + log_error("System hostname is not UTF-8 clean."); + return -EINVAL; + } + + r = dns_label_escape_new(label, r, &n); + if (r < 0) + return log_error_errno(r, "Failed to escape host name: %m"); + + if (is_localhost(n)) { + log_debug("System hostname is 'localhost', ignoring."); + return -EINVAL; + } + + r = dns_name_concat(n, "local", mdns_hostname); + if (r < 0) + return log_error_errno(r, "Failed to determine mDNS hostname: %m"); + + *llmnr_hostname = n; + n = NULL; + + return 0; +} + +static int on_hostname_change(sd_event_source *es, int fd, uint32_t revents, void *userdata) { + _cleanup_free_ char *llmnr_hostname = NULL, *mdns_hostname = NULL; + Manager *m = userdata; + int r; + + assert(m); + + r = determine_hostname(&llmnr_hostname, &mdns_hostname); + if (r < 0) + return 0; /* ignore invalid hostnames */ + + if (streq(llmnr_hostname, m->llmnr_hostname) && streq(mdns_hostname, m->mdns_hostname)) + return 0; + + log_info("System hostname changed to '%s'.", llmnr_hostname); + + free(m->llmnr_hostname); + free(m->mdns_hostname); + + m->llmnr_hostname = llmnr_hostname; + m->mdns_hostname = mdns_hostname; + + llmnr_hostname = mdns_hostname = NULL; + + manager_refresh_rrs(m); + + return 0; +} + +static int manager_watch_hostname(Manager *m) { + int r; + + assert(m); + + m->hostname_fd = open("/proc/sys/kernel/hostname", O_RDONLY|O_CLOEXEC|O_NDELAY|O_NOCTTY); + if (m->hostname_fd < 0) { + log_warning_errno(errno, "Failed to watch hostname: %m"); + return 0; + } + + r = sd_event_add_io(m->event, &m->hostname_event_source, m->hostname_fd, 0, on_hostname_change, m); + if (r < 0) { + if (r == -EPERM) + /* kernels prior to 3.2 don't support polling this file. Ignore the failure. */ + m->hostname_fd = safe_close(m->hostname_fd); + else + return log_error_errno(r, "Failed to add hostname event source: %m"); + } + + (void) sd_event_source_set_description(m->hostname_event_source, "hostname"); + + r = determine_hostname(&m->llmnr_hostname, &m->mdns_hostname); + if (r < 0) { + log_info("Defaulting to hostname 'gnu-linux'."); + m->llmnr_hostname = strdup("gnu-linux"); + if (!m->llmnr_hostname) + return log_oom(); + + m->mdns_hostname = strdup("gnu-linux.local"); + if (!m->mdns_hostname) + return log_oom(); + } else + log_info("Using system hostname '%s'.", m->llmnr_hostname); + + return 0; +} + +static int manager_sigusr1(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) { + _cleanup_free_ char *buffer = NULL; + _cleanup_fclose_ FILE *f = NULL; + Manager *m = userdata; + size_t size = 0; + DnsScope *scope; + + assert(s); + assert(si); + assert(m); + + f = open_memstream(&buffer, &size); + if (!f) + return log_oom(); + + LIST_FOREACH(scopes, scope, m->dns_scopes) + dns_scope_dump(scope, f); + + if (fflush_and_check(f) < 0) + return log_oom(); + + log_dump(LOG_INFO, buffer); + return 0; +} + +static int manager_sigusr2(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) { + Manager *m = userdata; + + assert(s); + assert(si); + assert(m); + + manager_flush_caches(m); + + return 0; +} + +int manager_new(Manager **ret) { + _cleanup_(manager_freep) Manager *m = NULL; + int r; + + assert(ret); + + m = new0(Manager, 1); + if (!m) + return -ENOMEM; + + m->llmnr_ipv4_udp_fd = m->llmnr_ipv6_udp_fd = -1; + m->llmnr_ipv4_tcp_fd = m->llmnr_ipv6_tcp_fd = -1; + m->mdns_ipv4_fd = m->mdns_ipv6_fd = -1; + m->dns_stub_udp_fd = m->dns_stub_tcp_fd = -1; + m->hostname_fd = -1; + + m->llmnr_support = RESOLVE_SUPPORT_YES; + m->mdns_support = RESOLVE_SUPPORT_NO; + m->dnssec_mode = DEFAULT_DNSSEC_MODE; + m->enable_cache = true; + m->dns_stub_listener_mode = DNS_STUB_LISTENER_UDP; + m->read_resolv_conf = true; + m->need_builtin_fallbacks = true; + m->etc_hosts_last = m->etc_hosts_mtime = USEC_INFINITY; + + r = dns_trust_anchor_load(&m->trust_anchor); + if (r < 0) + return r; + + r = manager_parse_config_file(m); + if (r < 0) + return r; + + r = sd_event_default(&m->event); + if (r < 0) + return r; + + sd_event_add_signal(m->event, NULL, SIGTERM, NULL, NULL); + sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL); + + sd_event_set_watchdog(m->event, true); + + r = manager_watch_hostname(m); + if (r < 0) + return r; + + r = dns_scope_new(m, &m->unicast_scope, NULL, DNS_PROTOCOL_DNS, AF_UNSPEC); + if (r < 0) + return r; + + r = manager_network_monitor_listen(m); + if (r < 0) + return r; + + r = manager_rtnl_listen(m); + if (r < 0) + return r; + + r = manager_connect_bus(m); + if (r < 0) + return r; + + (void) sd_event_add_signal(m->event, &m->sigusr1_event_source, SIGUSR1, manager_sigusr1, m); + (void) sd_event_add_signal(m->event, &m->sigusr2_event_source, SIGUSR2, manager_sigusr2, m); + + manager_cleanup_saved_user(m); + + *ret = m; + m = NULL; + + return 0; +} + +int manager_start(Manager *m) { + int r; + + assert(m); + + r = manager_dns_stub_start(m); + if (r < 0) + return r; + + r = manager_llmnr_start(m); + if (r < 0) + return r; + + r = manager_mdns_start(m); + if (r < 0) + return r; + + return 0; +} + +Manager *manager_free(Manager *m) { + Link *l; + + if (!m) + return NULL; + + dns_server_unlink_all(m->dns_servers); + dns_server_unlink_all(m->fallback_dns_servers); + dns_search_domain_unlink_all(m->search_domains); + + while ((l = hashmap_first(m->links))) + link_free(l); + + while (m->dns_queries) + dns_query_free(m->dns_queries); + + dns_scope_free(m->unicast_scope); + + /* At this point only orphaned streams should remain. All others should have been freed already by their + * owners */ + while (m->dns_streams) + dns_stream_unref(m->dns_streams); + + hashmap_free(m->links); + hashmap_free(m->dns_transactions); + + sd_event_source_unref(m->network_event_source); + sd_network_monitor_unref(m->network_monitor); + + sd_netlink_unref(m->rtnl); + sd_event_source_unref(m->rtnl_event_source); + + manager_llmnr_stop(m); + manager_mdns_stop(m); + manager_dns_stub_stop(m); + + sd_bus_slot_unref(m->prepare_for_sleep_slot); + sd_event_source_unref(m->bus_retry_event_source); + sd_bus_unref(m->bus); + + sd_event_source_unref(m->sigusr1_event_source); + sd_event_source_unref(m->sigusr2_event_source); + + sd_event_unref(m->event); + + dns_resource_key_unref(m->llmnr_host_ipv4_key); + dns_resource_key_unref(m->llmnr_host_ipv6_key); + + sd_event_source_unref(m->hostname_event_source); + safe_close(m->hostname_fd); + free(m->llmnr_hostname); + free(m->mdns_hostname); + + dns_trust_anchor_flush(&m->trust_anchor); + manager_etc_hosts_flush(m); + + return mfree(m); +} + +int manager_recv(Manager *m, int fd, DnsProtocol protocol, DnsPacket **ret) { + _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; + union { + struct cmsghdr header; /* For alignment */ + uint8_t buffer[CMSG_SPACE(MAXSIZE(struct in_pktinfo, struct in6_pktinfo)) + + CMSG_SPACE(int) /* ttl/hoplimit */ + + EXTRA_CMSG_SPACE /* kernel appears to require extra buffer space */]; + } control; + union sockaddr_union sa; + struct msghdr mh = {}; + struct cmsghdr *cmsg; + struct iovec iov; + ssize_t ms, l; + int r; + + assert(m); + assert(fd >= 0); + assert(ret); + + ms = next_datagram_size_fd(fd); + if (ms < 0) + return ms; + + r = dns_packet_new(&p, protocol, ms); + if (r < 0) + return r; + + iov.iov_base = DNS_PACKET_DATA(p); + iov.iov_len = p->allocated; + + mh.msg_name = &sa.sa; + mh.msg_namelen = sizeof(sa); + mh.msg_iov = &iov; + mh.msg_iovlen = 1; + mh.msg_control = &control; + mh.msg_controllen = sizeof(control); + + l = recvmsg(fd, &mh, 0); + if (l == 0) + return 0; + if (l < 0) { + if (errno == EAGAIN || errno == EINTR) + return 0; + + return -errno; + } + + assert(!(mh.msg_flags & MSG_CTRUNC)); + assert(!(mh.msg_flags & MSG_TRUNC)); + + p->size = (size_t) l; + + p->family = sa.sa.sa_family; + p->ipproto = IPPROTO_UDP; + if (p->family == AF_INET) { + p->sender.in = sa.in.sin_addr; + p->sender_port = be16toh(sa.in.sin_port); + } else if (p->family == AF_INET6) { + p->sender.in6 = sa.in6.sin6_addr; + p->sender_port = be16toh(sa.in6.sin6_port); + p->ifindex = sa.in6.sin6_scope_id; + } else + return -EAFNOSUPPORT; + + CMSG_FOREACH(cmsg, &mh) { + + if (cmsg->cmsg_level == IPPROTO_IPV6) { + assert(p->family == AF_INET6); + + switch (cmsg->cmsg_type) { + + case IPV6_PKTINFO: { + struct in6_pktinfo *i = (struct in6_pktinfo*) CMSG_DATA(cmsg); + + if (p->ifindex <= 0) + p->ifindex = i->ipi6_ifindex; + + p->destination.in6 = i->ipi6_addr; + break; + } + + case IPV6_HOPLIMIT: + p->ttl = *(int *) CMSG_DATA(cmsg); + break; + + } + } else if (cmsg->cmsg_level == IPPROTO_IP) { + assert(p->family == AF_INET); + + switch (cmsg->cmsg_type) { + + case IP_PKTINFO: { + struct in_pktinfo *i = (struct in_pktinfo*) CMSG_DATA(cmsg); + + if (p->ifindex <= 0) + p->ifindex = i->ipi_ifindex; + + p->destination.in = i->ipi_addr; + break; + } + + case IP_TTL: + p->ttl = *(int *) CMSG_DATA(cmsg); + break; + } + } + } + + /* The Linux kernel sets the interface index to the loopback + * device if the packet came from the local host since it + * avoids the routing table in such a case. Let's unset the + * interface index in such a case. */ + if (p->ifindex == LOOPBACK_IFINDEX) + p->ifindex = 0; + + if (protocol != DNS_PROTOCOL_DNS) { + /* If we don't know the interface index still, we look for the + * first local interface with a matching address. Yuck! */ + if (p->ifindex <= 0) + p->ifindex = manager_find_ifindex(m, p->family, &p->destination); + } + + *ret = p; + p = NULL; + + return 1; +} + +static int sendmsg_loop(int fd, struct msghdr *mh, int flags) { + int r; + + assert(fd >= 0); + assert(mh); + + for (;;) { + if (sendmsg(fd, mh, flags) >= 0) + return 0; + + if (errno == EINTR) + continue; + + if (errno != EAGAIN) + return -errno; + + r = fd_wait_for_event(fd, POLLOUT, SEND_TIMEOUT_USEC); + if (r < 0) + return r; + if (r == 0) + return -ETIMEDOUT; + } +} + +static int write_loop(int fd, void *message, size_t length) { + int r; + + assert(fd >= 0); + assert(message); + + for (;;) { + if (write(fd, message, length) >= 0) + return 0; + + if (errno == EINTR) + continue; + + if (errno != EAGAIN) + return -errno; + + r = fd_wait_for_event(fd, POLLOUT, SEND_TIMEOUT_USEC); + if (r < 0) + return r; + if (r == 0) + return -ETIMEDOUT; + } +} + +int manager_write(Manager *m, int fd, DnsPacket *p) { + int r; + + log_debug("Sending %s packet with id %" PRIu16 ".", DNS_PACKET_QR(p) ? "response" : "query", DNS_PACKET_ID(p)); + + r = write_loop(fd, DNS_PACKET_DATA(p), p->size); + if (r < 0) + return r; + + return 0; +} + +static int manager_ipv4_send( + Manager *m, + int fd, + int ifindex, + const struct in_addr *destination, + uint16_t port, + const struct in_addr *source, + DnsPacket *p) { + union sockaddr_union sa = { + .in.sin_family = AF_INET, + }; + union { + struct cmsghdr header; /* For alignment */ + uint8_t buffer[CMSG_SPACE(sizeof(struct in_pktinfo))]; + } control; + struct msghdr mh = {}; + struct iovec iov; + + assert(m); + assert(fd >= 0); + assert(destination); + assert(port > 0); + assert(p); + + iov.iov_base = DNS_PACKET_DATA(p); + iov.iov_len = p->size; + + sa.in.sin_addr = *destination; + sa.in.sin_port = htobe16(port), + + mh.msg_iov = &iov; + mh.msg_iovlen = 1; + mh.msg_name = &sa.sa; + mh.msg_namelen = sizeof(sa.in); + + if (ifindex > 0) { + struct cmsghdr *cmsg; + struct in_pktinfo *pi; + + zero(control); + + mh.msg_control = &control; + mh.msg_controllen = CMSG_LEN(sizeof(struct in_pktinfo)); + + cmsg = CMSG_FIRSTHDR(&mh); + cmsg->cmsg_len = mh.msg_controllen; + cmsg->cmsg_level = IPPROTO_IP; + cmsg->cmsg_type = IP_PKTINFO; + + pi = (struct in_pktinfo*) CMSG_DATA(cmsg); + pi->ipi_ifindex = ifindex; + + if (source) + pi->ipi_spec_dst = *source; + } + + return sendmsg_loop(fd, &mh, 0); +} + +static int manager_ipv6_send( + Manager *m, + int fd, + int ifindex, + const struct in6_addr *destination, + uint16_t port, + const struct in6_addr *source, + DnsPacket *p) { + + union sockaddr_union sa = { + .in6.sin6_family = AF_INET6, + }; + union { + struct cmsghdr header; /* For alignment */ + uint8_t buffer[CMSG_SPACE(sizeof(struct in6_pktinfo))]; + } control; + struct msghdr mh = {}; + struct iovec iov; + + assert(m); + assert(fd >= 0); + assert(destination); + assert(port > 0); + assert(p); + + iov.iov_base = DNS_PACKET_DATA(p); + iov.iov_len = p->size; + + sa.in6.sin6_addr = *destination; + sa.in6.sin6_port = htobe16(port), + sa.in6.sin6_scope_id = ifindex; + + mh.msg_iov = &iov; + mh.msg_iovlen = 1; + mh.msg_name = &sa.sa; + mh.msg_namelen = sizeof(sa.in6); + + if (ifindex > 0) { + struct cmsghdr *cmsg; + struct in6_pktinfo *pi; + + zero(control); + + mh.msg_control = &control; + mh.msg_controllen = CMSG_LEN(sizeof(struct in6_pktinfo)); + + cmsg = CMSG_FIRSTHDR(&mh); + cmsg->cmsg_len = mh.msg_controllen; + cmsg->cmsg_level = IPPROTO_IPV6; + cmsg->cmsg_type = IPV6_PKTINFO; + + pi = (struct in6_pktinfo*) CMSG_DATA(cmsg); + pi->ipi6_ifindex = ifindex; + + if (source) + pi->ipi6_addr = *source; + } + + return sendmsg_loop(fd, &mh, 0); +} + +int manager_send( + Manager *m, + int fd, + int ifindex, + int family, + const union in_addr_union *destination, + uint16_t port, + const union in_addr_union *source, + DnsPacket *p) { + + assert(m); + assert(fd >= 0); + assert(destination); + assert(port > 0); + assert(p); + + log_debug("Sending %s packet with id %" PRIu16 " on interface %i/%s.", DNS_PACKET_QR(p) ? "response" : "query", DNS_PACKET_ID(p), ifindex, af_to_name(family)); + + if (family == AF_INET) + return manager_ipv4_send(m, fd, ifindex, &destination->in, port, &source->in, p); + if (family == AF_INET6) + return manager_ipv6_send(m, fd, ifindex, &destination->in6, port, &source->in6, p); + + return -EAFNOSUPPORT; +} + +uint32_t manager_find_mtu(Manager *m) { + uint32_t mtu = 0; + Link *l; + Iterator i; + + /* If we don't know on which link a DNS packet would be + * delivered, let's find the largest MTU that works on all + * interfaces we know of */ + + HASHMAP_FOREACH(l, m->links, i) { + if (l->mtu <= 0) + continue; + + if (mtu <= 0 || l->mtu < mtu) + mtu = l->mtu; + } + + return mtu; +} + +int manager_find_ifindex(Manager *m, int family, const union in_addr_union *in_addr) { + LinkAddress *a; + + assert(m); + + a = manager_find_link_address(m, family, in_addr); + if (a) + return a->link->ifindex; + + return 0; +} + +void manager_refresh_rrs(Manager *m) { + Iterator i; + Link *l; + + assert(m); + + m->llmnr_host_ipv4_key = dns_resource_key_unref(m->llmnr_host_ipv4_key); + m->llmnr_host_ipv6_key = dns_resource_key_unref(m->llmnr_host_ipv6_key); + + HASHMAP_FOREACH(l, m->links, i) { + link_add_rrs(l, true); + link_add_rrs(l, false); + } +} + +int manager_next_hostname(Manager *m) { + const char *p; + uint64_t u, a; + char *h, *k; + int r; + + assert(m); + + p = strchr(m->llmnr_hostname, 0); + assert(p); + + while (p > m->llmnr_hostname) { + if (!strchr("0123456789", p[-1])) + break; + + p--; + } + + if (*p == 0 || safe_atou64(p, &u) < 0 || u <= 0) + u = 1; + + /* Add a random number to the old value. This way we can avoid + * that two hosts pick the same hostname, win on IPv4 and lose + * on IPv6 (or vice versa), and pick the same hostname + * replacement hostname, ad infinitum. We still want the + * numbers to go up monotonically, hence we just add a random + * value 1..10 */ + + random_bytes(&a, sizeof(a)); + u += 1 + a % 10; + + if (asprintf(&h, "%.*s%" PRIu64, (int) (p - m->llmnr_hostname), m->llmnr_hostname, u) < 0) + return -ENOMEM; + + r = dns_name_concat(h, "local", &k); + if (r < 0) { + free(h); + return r; + } + + log_info("Hostname conflict, changing published hostname from '%s' to '%s'.", m->llmnr_hostname, h); + + free(m->llmnr_hostname); + m->llmnr_hostname = h; + + free(m->mdns_hostname); + m->mdns_hostname = k; + + manager_refresh_rrs(m); + + return 0; +} + +LinkAddress* manager_find_link_address(Manager *m, int family, const union in_addr_union *in_addr) { + Iterator i; + Link *l; + + assert(m); + + HASHMAP_FOREACH(l, m->links, i) { + LinkAddress *a; + + a = link_find_address(l, family, in_addr); + if (a) + return a; + } + + return NULL; +} + +bool manager_our_packet(Manager *m, DnsPacket *p) { + assert(m); + assert(p); + + return !!manager_find_link_address(m, p->family, &p->sender); +} + +DnsScope* manager_find_scope(Manager *m, DnsPacket *p) { + Link *l; + + assert(m); + assert(p); + + l = hashmap_get(m->links, INT_TO_PTR(p->ifindex)); + if (!l) + return NULL; + + switch (p->protocol) { + case DNS_PROTOCOL_LLMNR: + if (p->family == AF_INET) + return l->llmnr_ipv4_scope; + else if (p->family == AF_INET6) + return l->llmnr_ipv6_scope; + + break; + + case DNS_PROTOCOL_MDNS: + if (p->family == AF_INET) + return l->mdns_ipv4_scope; + else if (p->family == AF_INET6) + return l->mdns_ipv6_scope; + + break; + + default: + break; + } + + return NULL; +} + +void manager_verify_all(Manager *m) { + DnsScope *s; + + assert(m); + + LIST_FOREACH(scopes, s, m->dns_scopes) + dns_zone_verify_all(&s->zone); +} + +int manager_is_own_hostname(Manager *m, const char *name) { + int r; + + assert(m); + assert(name); + + if (m->llmnr_hostname) { + r = dns_name_equal(name, m->llmnr_hostname); + if (r != 0) + return r; + } + + if (m->mdns_hostname) + return dns_name_equal(name, m->mdns_hostname); + + return 0; +} + +int manager_compile_dns_servers(Manager *m, OrderedSet **dns) { + DnsServer *s; + Iterator i; + Link *l; + int r; + + assert(m); + assert(dns); + + r = ordered_set_ensure_allocated(dns, &dns_server_hash_ops); + if (r < 0) + return r; + + /* First add the system-wide servers and domains */ + LIST_FOREACH(servers, s, m->dns_servers) { + r = ordered_set_put(*dns, s); + if (r == -EEXIST) + continue; + if (r < 0) + return r; + } + + /* Then, add the per-link servers */ + HASHMAP_FOREACH(l, m->links, i) { + LIST_FOREACH(servers, s, l->dns_servers) { + r = ordered_set_put(*dns, s); + if (r == -EEXIST) + continue; + if (r < 0) + return r; + } + } + + /* If we found nothing, add the fallback servers */ + if (ordered_set_isempty(*dns)) { + LIST_FOREACH(servers, s, m->fallback_dns_servers) { + r = ordered_set_put(*dns, s); + if (r == -EEXIST) + continue; + if (r < 0) + return r; + } + } + + return 0; +} + +/* filter_route is a tri-state: + * < 0: no filtering + * = 0 or false: return only domains which should be used for searching + * > 0 or true: return only domains which are for routing only + */ +int manager_compile_search_domains(Manager *m, OrderedSet **domains, int filter_route) { + DnsSearchDomain *d; + Iterator i; + Link *l; + int r; + + assert(m); + assert(domains); + + r = ordered_set_ensure_allocated(domains, &dns_name_hash_ops); + if (r < 0) + return r; + + LIST_FOREACH(domains, d, m->search_domains) { + + if (filter_route >= 0 && + d->route_only != !!filter_route) + continue; + + r = ordered_set_put(*domains, d->name); + if (r == -EEXIST) + continue; + if (r < 0) + return r; + } + + HASHMAP_FOREACH(l, m->links, i) { + + LIST_FOREACH(domains, d, l->search_domains) { + + if (filter_route >= 0 && + d->route_only != !!filter_route) + continue; + + r = ordered_set_put(*domains, d->name); + if (r == -EEXIST) + continue; + if (r < 0) + return r; + } + } + + return 0; +} + +DnssecMode manager_get_dnssec_mode(Manager *m) { + assert(m); + + if (m->dnssec_mode != _DNSSEC_MODE_INVALID) + return m->dnssec_mode; + + return DNSSEC_NO; +} + +bool manager_dnssec_supported(Manager *m) { + DnsServer *server; + Iterator i; + Link *l; + + assert(m); + + if (manager_get_dnssec_mode(m) == DNSSEC_NO) + return false; + + server = manager_get_dns_server(m); + if (server && !dns_server_dnssec_supported(server)) + return false; + + HASHMAP_FOREACH(l, m->links, i) + if (!link_dnssec_supported(l)) + return false; + + return true; +} + +void manager_dnssec_verdict(Manager *m, DnssecVerdict verdict, const DnsResourceKey *key) { + + assert(verdict >= 0); + assert(verdict < _DNSSEC_VERDICT_MAX); + + if (log_get_max_level() >= LOG_DEBUG) { + char s[DNS_RESOURCE_KEY_STRING_MAX]; + + log_debug("Found verdict for lookup %s: %s", + dns_resource_key_to_string(key, s, sizeof s), + dnssec_verdict_to_string(verdict)); + } + + m->n_dnssec_verdict[verdict]++; +} + +bool manager_routable(Manager *m, int family) { + Iterator i; + Link *l; + + assert(m); + + /* Returns true if the host has at least one interface with a routable address of the specified type */ + + HASHMAP_FOREACH(l, m->links, i) + if (link_relevant(l, family, false)) + return true; + + return false; +} + +void manager_flush_caches(Manager *m) { + DnsScope *scope; + + assert(m); + + LIST_FOREACH(scopes, scope, m->dns_scopes) + dns_cache_flush(&scope->cache); + + log_info("Flushed all caches."); +} + +void manager_cleanup_saved_user(Manager *m) { + _cleanup_closedir_ DIR *d = NULL; + struct dirent *de; + int r; + + assert(m); + + /* Clean up all saved per-link files in /run/systemd/resolve/netif/ that don't have a matching interface + * anymore. These files are created to persist settings pushed in by the user via the bus, so that resolved can + * be restarted without losing this data. */ + + d = opendir("/run/systemd/resolve/netif/"); + if (!d) { + if (errno == ENOENT) + return; + + log_warning_errno(errno, "Failed to open interface directory: %m"); + return; + } + + FOREACH_DIRENT_ALL(de, d, log_error_errno(errno, "Failed to read interface directory: %m")) { + _cleanup_free_ char *p = NULL; + int ifindex; + Link *l; + + if (!IN_SET(de->d_type, DT_UNKNOWN, DT_REG)) + continue; + + if (STR_IN_SET(de->d_name, ".", "..")) + continue; + + r = parse_ifindex(de->d_name, &ifindex); + if (r < 0) /* Probably some temporary file from a previous run. Delete it */ + goto rm; + + l = hashmap_get(m->links, INT_TO_PTR(ifindex)); + if (!l) /* link vanished */ + goto rm; + + if (l->is_managed) /* now managed by networkd, hence the bus settings are useless */ + goto rm; + + continue; + + rm: + p = strappend("/run/systemd/resolve/netif/", de->d_name); + if (!p) { + log_oom(); + return; + } + + (void) unlink(p); + } +} diff --git a/src/grp-resolve/systemd-resolved/resolved-manager.h b/src/grp-resolve/systemd-resolved/resolved-manager.h new file mode 100644 index 0000000000..4e9dcd51f1 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-manager.h @@ -0,0 +1,185 @@ +#pragma once + +/*** + This file is part of systemd. + + Copyright 2014 Tom Gundersen <teg@jklm.no> + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include <systemd/sd-event.h> + +#include "systemd-basic/hashmap.h" +#include "systemd-basic/list.h" +#include "systemd-basic/ordered-set.h" +#include "systemd-shared/resolve-util.h" +#include "systemd-staging/sd-netlink.h" +#include "systemd-staging/sd-network.h" + +typedef struct Manager Manager; + +#include "resolved-conf.h" +#include "resolved-dns-query.h" +#include "resolved-dns-search-domain.h" +#include "resolved-dns-server.h" +#include "resolved-dns-stream.h" +#include "resolved-dns-trust-anchor.h" +#include "resolved-link.h" + +#define MANAGER_SEARCH_DOMAINS_MAX 32 +#define MANAGER_DNS_SERVERS_MAX 32 + +struct Manager { + sd_event *event; + + ResolveSupport llmnr_support; + ResolveSupport mdns_support; + DnssecMode dnssec_mode; + bool enable_cache; + DnsStubListenerMode dns_stub_listener_mode; + + /* Network */ + Hashmap *links; + + sd_netlink *rtnl; + sd_event_source *rtnl_event_source; + + sd_network_monitor *network_monitor; + sd_event_source *network_event_source; + + /* DNS query management */ + Hashmap *dns_transactions; + LIST_HEAD(DnsQuery, dns_queries); + unsigned n_dns_queries; + + LIST_HEAD(DnsStream, dns_streams); + unsigned n_dns_streams; + + /* Unicast dns */ + LIST_HEAD(DnsServer, dns_servers); + LIST_HEAD(DnsServer, fallback_dns_servers); + unsigned n_dns_servers; /* counts both main and fallback */ + DnsServer *current_dns_server; + + LIST_HEAD(DnsSearchDomain, search_domains); + unsigned n_search_domains; + + bool need_builtin_fallbacks:1; + + bool read_resolv_conf:1; + usec_t resolv_conf_mtime; + + DnsTrustAnchor trust_anchor; + + LIST_HEAD(DnsScope, dns_scopes); + DnsScope *unicast_scope; + + /* LLMNR */ + int llmnr_ipv4_udp_fd; + int llmnr_ipv6_udp_fd; + int llmnr_ipv4_tcp_fd; + int llmnr_ipv6_tcp_fd; + + sd_event_source *llmnr_ipv4_udp_event_source; + sd_event_source *llmnr_ipv6_udp_event_source; + sd_event_source *llmnr_ipv4_tcp_event_source; + sd_event_source *llmnr_ipv6_tcp_event_source; + + /* mDNS */ + int mdns_ipv4_fd; + int mdns_ipv6_fd; + + sd_event_source *mdns_ipv4_event_source; + sd_event_source *mdns_ipv6_event_source; + + /* dbus */ + sd_bus *bus; + sd_event_source *bus_retry_event_source; + + /* The hostname we publish on LLMNR and mDNS */ + char *llmnr_hostname; + char *mdns_hostname; + DnsResourceKey *llmnr_host_ipv4_key; + DnsResourceKey *llmnr_host_ipv6_key; + + /* Watch the system hostname */ + int hostname_fd; + sd_event_source *hostname_event_source; + + /* Watch for system suspends */ + sd_bus_slot *prepare_for_sleep_slot; + + sd_event_source *sigusr1_event_source; + sd_event_source *sigusr2_event_source; + + unsigned n_transactions_total; + unsigned n_dnssec_verdict[_DNSSEC_VERDICT_MAX]; + + /* Data from /etc/hosts */ + Set* etc_hosts_by_address; + Hashmap* etc_hosts_by_name; + usec_t etc_hosts_last, etc_hosts_mtime; + + /* Local DNS stub on 127.0.0.53:53 */ + int dns_stub_udp_fd; + int dns_stub_tcp_fd; + + sd_event_source *dns_stub_udp_event_source; + sd_event_source *dns_stub_tcp_event_source; +}; + +/* Manager */ + +int manager_new(Manager **ret); +Manager* manager_free(Manager *m); + +int manager_start(Manager *m); + +uint32_t manager_find_mtu(Manager *m); + +int manager_write(Manager *m, int fd, DnsPacket *p); +int manager_send(Manager *m, int fd, int ifindex, int family, const union in_addr_union *destination, uint16_t port, const union in_addr_union *source, DnsPacket *p); +int manager_recv(Manager *m, int fd, DnsProtocol protocol, DnsPacket **ret); + +int manager_find_ifindex(Manager *m, int family, const union in_addr_union *in_addr); +LinkAddress* manager_find_link_address(Manager *m, int family, const union in_addr_union *in_addr); + +void manager_refresh_rrs(Manager *m); +int manager_next_hostname(Manager *m); + +bool manager_our_packet(Manager *m, DnsPacket *p); +DnsScope* manager_find_scope(Manager *m, DnsPacket *p); + +void manager_verify_all(Manager *m); + +DEFINE_TRIVIAL_CLEANUP_FUNC(Manager*, manager_free); + +#define EXTRA_CMSG_SPACE 1024 + +int manager_is_own_hostname(Manager *m, const char *name); + +int manager_compile_dns_servers(Manager *m, OrderedSet **servers); +int manager_compile_search_domains(Manager *m, OrderedSet **domains, int filter_route); + +DnssecMode manager_get_dnssec_mode(Manager *m); +bool manager_dnssec_supported(Manager *m); + +void manager_dnssec_verdict(Manager *m, DnssecVerdict verdict, const DnsResourceKey *key); + +bool manager_routable(Manager *m, int family); + +void manager_flush_caches(Manager *m); + +void manager_cleanup_saved_user(Manager *m); diff --git a/src/grp-resolve/systemd-resolved/resolved-mdns.c b/src/grp-resolve/systemd-resolved/resolved-mdns.c new file mode 100644 index 0000000000..f810019763 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-mdns.c @@ -0,0 +1,288 @@ +/*** + This file is part of systemd. + + Copyright 2015 Daniel Mack + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. + ***/ + +#include <arpa/inet.h> +#include <netinet/in.h> +#include <resolv.h> + +#include "systemd-basic/fd-util.h" + +#include "resolved-manager.h" +#include "resolved-mdns.h" + +void manager_mdns_stop(Manager *m) { + assert(m); + + m->mdns_ipv4_event_source = sd_event_source_unref(m->mdns_ipv4_event_source); + m->mdns_ipv4_fd = safe_close(m->mdns_ipv4_fd); + + m->mdns_ipv6_event_source = sd_event_source_unref(m->mdns_ipv6_event_source); + m->mdns_ipv6_fd = safe_close(m->mdns_ipv6_fd); +} + +int manager_mdns_start(Manager *m) { + int r; + + assert(m); + + if (m->mdns_support == RESOLVE_SUPPORT_NO) + return 0; + + r = manager_mdns_ipv4_fd(m); + if (r == -EADDRINUSE) + goto eaddrinuse; + if (r < 0) + return r; + + if (socket_ipv6_is_supported()) { + r = manager_mdns_ipv6_fd(m); + if (r == -EADDRINUSE) + goto eaddrinuse; + if (r < 0) + return r; + } + + return 0; + +eaddrinuse: + log_warning("There appears to be another mDNS responder running. Turning off mDNS support."); + m->mdns_support = RESOLVE_SUPPORT_NO; + manager_mdns_stop(m); + + return 0; +} + +static int on_mdns_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) { + _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; + Manager *m = userdata; + DnsScope *scope; + int r; + + r = manager_recv(m, fd, DNS_PROTOCOL_MDNS, &p); + if (r <= 0) + return r; + + scope = manager_find_scope(m, p); + if (!scope) { + log_warning("Got mDNS UDP packet on unknown scope. Ignoring."); + return 0; + } + + if (dns_packet_validate_reply(p) > 0) { + DnsResourceRecord *rr; + + log_debug("Got mDNS reply packet"); + + /* + * mDNS is different from regular DNS and LLMNR with regard to handling responses. + * While on other protocols, we can ignore every answer that doesn't match a question + * we broadcast earlier, RFC6762, section 18.1 recommends looking at and caching all + * incoming information, regardless of the DNS packet ID. + * + * Hence, extract the packet here, and try to find a transaction for answer the we got + * and complete it. Also store the new information in scope's cache. + */ + r = dns_packet_extract(p); + if (r < 0) { + log_debug("mDNS packet extraction failed."); + return 0; + } + + dns_scope_check_conflicts(scope, p); + + DNS_ANSWER_FOREACH(rr, p->answer) { + const char *name = dns_resource_key_name(rr->key); + DnsTransaction *t; + + /* If the received reply packet contains ANY record that is not .local or .in-addr.arpa, + * we assume someone's playing tricks on us and discard the packet completely. */ + if (!(dns_name_endswith(name, "in-addr.arpa") > 0 || + dns_name_endswith(name, "local") > 0)) + return 0; + + t = dns_scope_find_transaction(scope, rr->key, false); + if (t) + dns_transaction_process_reply(t, p); + } + + dns_cache_put(&scope->cache, NULL, DNS_PACKET_RCODE(p), p->answer, false, (uint32_t) -1, 0, p->family, &p->sender); + + } else if (dns_packet_validate_query(p) > 0) { + log_debug("Got mDNS query packet for id %u", DNS_PACKET_ID(p)); + + dns_scope_process_query(scope, NULL, p); + } else + log_debug("Invalid mDNS UDP packet."); + + return 0; +} + +int manager_mdns_ipv4_fd(Manager *m) { + union sockaddr_union sa = { + .in.sin_family = AF_INET, + .in.sin_port = htobe16(MDNS_PORT), + }; + static const int one = 1, pmtu = IP_PMTUDISC_DONT, ttl = 255; + int r; + + assert(m); + + if (m->mdns_ipv4_fd >= 0) + return m->mdns_ipv4_fd; + + m->mdns_ipv4_fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); + if (m->mdns_ipv4_fd < 0) + return -errno; + + r = setsockopt(m->mdns_ipv4_fd, IPPROTO_IP, IP_TTL, &ttl, sizeof(ttl)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->mdns_ipv4_fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->mdns_ipv4_fd, IPPROTO_IP, IP_MULTICAST_LOOP, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->mdns_ipv4_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->mdns_ipv4_fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->mdns_ipv4_fd, IPPROTO_IP, IP_RECVTTL, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + /* Disable Don't-Fragment bit in the IP header */ + r = setsockopt(m->mdns_ipv4_fd, IPPROTO_IP, IP_MTU_DISCOVER, &pmtu, sizeof(pmtu)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = bind(m->mdns_ipv4_fd, &sa.sa, sizeof(sa.in)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = sd_event_add_io(m->event, &m->mdns_ipv4_event_source, m->mdns_ipv4_fd, EPOLLIN, on_mdns_packet, m); + if (r < 0) + goto fail; + + return m->mdns_ipv4_fd; + +fail: + m->mdns_ipv4_fd = safe_close(m->mdns_ipv4_fd); + return r; +} + +int manager_mdns_ipv6_fd(Manager *m) { + union sockaddr_union sa = { + .in6.sin6_family = AF_INET6, + .in6.sin6_port = htobe16(MDNS_PORT), + }; + static const int one = 1, ttl = 255; + int r; + + assert(m); + + if (m->mdns_ipv6_fd >= 0) + return m->mdns_ipv6_fd; + + m->mdns_ipv6_fd = socket(AF_INET6, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); + if (m->mdns_ipv6_fd < 0) + return -errno; + + r = setsockopt(m->mdns_ipv6_fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &ttl, sizeof(ttl)); + if (r < 0) { + r = -errno; + goto fail; + } + + /* RFC 4795, section 2.5 recommends setting the TTL of UDP packets to 255. */ + r = setsockopt(m->mdns_ipv6_fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &ttl, sizeof(ttl)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->mdns_ipv6_fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->mdns_ipv6_fd, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->mdns_ipv6_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->mdns_ipv6_fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->mdns_ipv6_fd, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = bind(m->mdns_ipv6_fd, &sa.sa, sizeof(sa.in6)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = sd_event_add_io(m->event, &m->mdns_ipv6_event_source, m->mdns_ipv6_fd, EPOLLIN, on_mdns_packet, m); + if (r < 0) + goto fail; + + return m->mdns_ipv6_fd; + +fail: + m->mdns_ipv6_fd = safe_close(m->mdns_ipv6_fd); + return r; +} diff --git a/src/grp-resolve/systemd-resolved/resolved-mdns.h b/src/grp-resolve/systemd-resolved/resolved-mdns.h new file mode 100644 index 0000000000..5d274648f4 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-mdns.h @@ -0,0 +1,30 @@ +#pragma once + +/*** + This file is part of systemd. + + Copyright 2015 Daniel Mack + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include "resolved-manager.h" + +#define MDNS_PORT 5353 + +int manager_mdns_ipv4_fd(Manager *m); +int manager_mdns_ipv6_fd(Manager *m); + +void manager_mdns_stop(Manager *m); +int manager_mdns_start(Manager *m); diff --git a/src/grp-resolve/systemd-resolved/resolved-resolv-conf.c b/src/grp-resolve/systemd-resolved/resolved-resolv-conf.c new file mode 100644 index 0000000000..5cc79a0040 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-resolv-conf.c @@ -0,0 +1,277 @@ +/*** + This file is part of systemd. + + Copyright 2014 Tom Gundersen <teg@jklm.no> + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. + ***/ + +#include <resolv.h> + +#include "systemd-basic/alloc-util.h" +#include "systemd-basic/fd-util.h" +#include "systemd-basic/fileio-label.h" +#include "systemd-basic/fileio.h" +#include "systemd-basic/ordered-set.h" +#include "systemd-basic/string-util.h" +#include "systemd-basic/strv.h" +#include "systemd-shared/dns-domain.h" + +#include "resolved-conf.h" +#include "resolved-resolv-conf.h" + +int manager_read_resolv_conf(Manager *m) { + _cleanup_fclose_ FILE *f = NULL; + struct stat st, own; + char line[LINE_MAX]; + usec_t t; + int r; + + assert(m); + + /* Reads the system /etc/resolv.conf, if it exists and is not + * symlinked to our own resolv.conf instance */ + + if (!m->read_resolv_conf) + return 0; + + r = stat("/etc/resolv.conf", &st); + if (r < 0) { + if (errno == ENOENT) + return 0; + + r = log_warning_errno(errno, "Failed to stat /etc/resolv.conf: %m"); + goto clear; + } + + /* Have we already seen the file? */ + t = timespec_load(&st.st_mtim); + if (t == m->resolv_conf_mtime) + return 0; + + /* Is it symlinked to our own file? */ + if (stat("/run/systemd/resolve/resolv.conf", &own) >= 0 && + st.st_dev == own.st_dev && + st.st_ino == own.st_ino) + return 0; + + f = fopen("/etc/resolv.conf", "re"); + if (!f) { + if (errno == ENOENT) + return 0; + + r = log_warning_errno(errno, "Failed to open /etc/resolv.conf: %m"); + goto clear; + } + + if (fstat(fileno(f), &st) < 0) { + r = log_error_errno(errno, "Failed to stat open file: %m"); + goto clear; + } + + dns_server_mark_all(m->dns_servers); + dns_search_domain_mark_all(m->search_domains); + + FOREACH_LINE(line, f, r = -errno; goto clear) { + const char *a; + char *l; + + l = strstrip(line); + if (*l == '#' || *l == ';') + continue; + + a = first_word(l, "nameserver"); + if (a) { + r = manager_parse_dns_server_string_and_warn(m, DNS_SERVER_SYSTEM, a); + if (r < 0) + log_warning_errno(r, "Failed to parse DNS server address '%s', ignoring.", a); + + continue; + } + + a = first_word(l, "domain"); + if (!a) /* We treat "domain" lines, and "search" lines as equivalent, and add both to our list. */ + a = first_word(l, "search"); + if (a) { + r = manager_parse_search_domains_and_warn(m, a); + if (r < 0) + log_warning_errno(r, "Failed to parse search domain string '%s', ignoring.", a); + } + } + + m->resolv_conf_mtime = t; + + /* Flush out all servers and search domains that are still + * marked. Those are then ones that didn't appear in the new + * /etc/resolv.conf */ + dns_server_unlink_marked(m->dns_servers); + dns_search_domain_unlink_marked(m->search_domains); + + /* Whenever /etc/resolv.conf changes, start using the first + * DNS server of it. This is useful to deal with broken + * network managing implementations (like NetworkManager), + * that when connecting to a VPN place both the VPN DNS + * servers and the local ones in /etc/resolv.conf. Without + * resetting the DNS server to use back to the first entry we + * will continue to use the local one thus being unable to + * resolve VPN domains. */ + manager_set_dns_server(m, m->dns_servers); + + /* Unconditionally flush the cache when /etc/resolv.conf is + * modified, even if the data it contained was completely + * identical to the previous version we used. We do this + * because altering /etc/resolv.conf is typically done when + * the network configuration changes, and that should be + * enough to flush the global unicast DNS cache. */ + if (m->unicast_scope) + dns_cache_flush(&m->unicast_scope->cache); + + return 0; + +clear: + dns_server_unlink_all(m->dns_servers); + dns_search_domain_unlink_all(m->search_domains); + return r; +} + +static void write_resolv_conf_server(DnsServer *s, FILE *f, unsigned *count) { + assert(s); + assert(f); + assert(count); + + if (!dns_server_string(s)) { + log_warning("Our of memory, or invalid DNS address. Ignoring server."); + return; + } + + /* Check if the DNS server is limited to particular domains; + * resolv.conf does not have a syntax to express that, so it must not + * appear as a global name server to avoid routing unrelated domains to + * it (which is a privacy violation, will most probably fail anyway, + * and adds unnecessary load) */ + if (dns_server_limited_domains(s)) { + log_debug("DNS server %s has route-only domains, not using as global name server", dns_server_string(s)); + return; + } + + if (*count == MAXNS) + fputs("# Too many DNS servers configured, the following entries may be ignored.\n", f); + (*count)++; + + fprintf(f, "nameserver %s\n", dns_server_string(s)); +} + +static void write_resolv_conf_search( + OrderedSet *domains, + FILE *f) { + unsigned length = 0, count = 0; + Iterator i; + char *domain; + + assert(domains); + assert(f); + + fputs("search", f); + + ORDERED_SET_FOREACH(domain, domains, i) { + if (++count > MAXDNSRCH) { + fputs("\n# Too many search domains configured, remaining ones ignored.", f); + break; + } + length += strlen(domain) + 1; + if (length > 256) { + fputs("\n# Total length of all search domains is too long, remaining ones ignored.", f); + break; + } + fputc(' ', f); + fputs(domain, f); + } + + fputs("\n", f); +} + +static int write_resolv_conf_contents(FILE *f, OrderedSet *dns, OrderedSet *domains) { + Iterator i; + + fputs("# This file is managed by systemd-resolved(8). Do not edit.\n#\n" + "# This is a dynamic resolv.conf file for connecting local clients directly to\n" + "# all known DNS servers.\n#\n" + "# Third party programs must not access this file directly, but only through the\n" + "# symlink at /etc/resolv.conf. To manage resolv.conf(5) in a different way,\n" + "# replace this symlink by a static file or a different symlink.\n#\n" + "# See systemd-resolved.service(8) for details about the supported modes of\n" + "# operation for /etc/resolv.conf.\n\n", f); + + if (ordered_set_isempty(dns)) + fputs("# No DNS servers known.\n", f); + else { + unsigned count = 0; + DnsServer *s; + + ORDERED_SET_FOREACH(s, dns, i) + write_resolv_conf_server(s, f, &count); + } + + if (!ordered_set_isempty(domains)) + write_resolv_conf_search(domains, f); + + return fflush_and_check(f); +} + +int manager_write_resolv_conf(Manager *m) { + + _cleanup_ordered_set_free_ OrderedSet *dns = NULL, *domains = NULL; + _cleanup_free_ char *temp_path = NULL; + _cleanup_fclose_ FILE *f = NULL; + int r; + + assert(m); + + /* Read the system /etc/resolv.conf first */ + (void) manager_read_resolv_conf(m); + + /* Add the full list to a set, to filter out duplicates */ + r = manager_compile_dns_servers(m, &dns); + if (r < 0) + return log_warning_errno(r, "Failed to compile list of DNS servers: %m"); + + r = manager_compile_search_domains(m, &domains, false); + if (r < 0) + return log_warning_errno(r, "Failed to compile list of search domains: %m"); + + r = fopen_temporary_label(PRIVATE_RESOLV_CONF, PRIVATE_RESOLV_CONF, &f, &temp_path); + if (r < 0) + return log_warning_errno(r, "Failed to open private resolv.conf file for writing: %m"); + + (void) fchmod(fileno(f), 0644); + + r = write_resolv_conf_contents(f, dns, domains); + if (r < 0) { + log_error_errno(r, "Failed to write private resolv.conf contents: %m"); + goto fail; + } + + if (rename(temp_path, PRIVATE_RESOLV_CONF) < 0) { + r = log_error_errno(errno, "Failed to move private resolv.conf file into place: %m"); + goto fail; + } + + return 0; + +fail: + (void) unlink(PRIVATE_RESOLV_CONF); + (void) unlink(temp_path); + + return r; +} diff --git a/src/grp-resolve/systemd-resolved/resolved-resolv-conf.h b/src/grp-resolve/systemd-resolved/resolved-resolv-conf.h new file mode 100644 index 0000000000..75fa080e4c --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved-resolv-conf.h @@ -0,0 +1,27 @@ +#pragma once + +/*** + This file is part of systemd. + + Copyright 2014 Tom Gundersen <teg@jklm.no> + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include "resolved-manager.h" + +#define PRIVATE_RESOLV_CONF "/run/systemd/resolve/resolv.conf" + +int manager_read_resolv_conf(Manager *m); +int manager_write_resolv_conf(Manager *m); diff --git a/src/grp-resolve/systemd-resolved/resolved.c b/src/grp-resolve/systemd-resolved/resolved.c new file mode 100644 index 0000000000..7fe9b7edbb --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved.c @@ -0,0 +1,121 @@ +/*** + This file is part of systemd. + + Copyright 2014 Tom Gundersen <teg@jklm.no> + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include <systemd/sd-daemon.h> +#include <systemd/sd-event.h> + +#include "systemd-basic/capability-util.h" +#include "systemd-basic/mkdir.h" +#include "systemd-basic/selinux-util.h" +#include "systemd-basic/signal-util.h" +#include "systemd-basic/user-util.h" + +#include "resolved-conf.h" +#include "resolved-manager.h" +#include "resolved-resolv-conf.h" + +int main(int argc, char *argv[]) { + _cleanup_(manager_freep) Manager *m = NULL; + const char *user = "systemd-resolve"; + uid_t uid; + gid_t gid; + int r; + + log_set_target(LOG_TARGET_AUTO); + log_parse_environment(); + log_open(); + + if (argc != 1) { + log_error("This program takes no arguments."); + r = -EINVAL; + goto finish; + } + + umask(0022); + + r = mac_selinux_init(); + if (r < 0) { + log_error_errno(r, "SELinux setup failed: %m"); + goto finish; + } + + r = get_user_creds(&user, &uid, &gid, NULL, NULL); + if (r < 0) { + log_error_errno(r, "Cannot resolve user name %s: %m", user); + goto finish; + } + + /* Always create the directory where resolv.conf will live */ + r = mkdir_safe_label("/run/systemd/resolve", 0755, uid, gid); + if (r < 0) { + log_error_errno(r, "Could not create runtime directory: %m"); + goto finish; + } + + /* Drop privileges, but keep three caps. Note that we drop those too, later on (see below) */ + r = drop_privileges(uid, gid, + (UINT64_C(1) << CAP_NET_RAW)| /* needed for SO_BINDTODEVICE */ + (UINT64_C(1) << CAP_NET_BIND_SERVICE)| /* needed to bind on port 53 */ + (UINT64_C(1) << CAP_SETPCAP) /* needed in order to drop the caps later */); + if (r < 0) + goto finish; + + assert_se(sigprocmask_many(SIG_BLOCK, NULL, SIGTERM, SIGINT, SIGUSR1, SIGUSR2, -1) >= 0); + + r = manager_new(&m); + if (r < 0) { + log_error_errno(r, "Could not create manager: %m"); + goto finish; + } + + r = manager_start(m); + if (r < 0) { + log_error_errno(r, "Failed to start manager: %m"); + goto finish; + } + + /* Write finish default resolv.conf to avoid a dangling symlink */ + (void) manager_write_resolv_conf(m); + + /* Let's drop the remaining caps now */ + r = capability_bounding_set_drop(0, true); + if (r < 0) { + log_error_errno(r, "Failed to drop remaining caps: %m"); + goto finish; + } + + sd_notify(false, + "READY=1\n" + "STATUS=Processing requests..."); + + r = sd_event_loop(m->event); + if (r < 0) { + log_error_errno(r, "Event loop failed: %m"); + goto finish; + } + + sd_event_get_exit_code(m->event, &r); + +finish: + sd_notify(false, + "STOPPING=1\n" + "STATUS=Shutting down..."); + + return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS; +} diff --git a/src/grp-resolve/systemd-resolved/resolved.conf.in b/src/grp-resolve/systemd-resolved/resolved.conf.in new file mode 100644 index 0000000000..60afa151e3 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved.conf.in @@ -0,0 +1,21 @@ +# This file is part of systemd. +# +# systemd is free software; you can redistribute it and/or modify it +# under the terms of the GNU Lesser General Public License as published by +# the Free Software Foundation; either version 2.1 of the License, or +# (at your option) any later version. +# +# Entries in this file show the compile time defaults. +# You can change settings by editing this file. +# Defaults can be restored by simply deleting this file. +# +# See resolved.conf(5) for details + +[Resolve] +#DNS= +#FallbackDNS=@DNS_SERVERS@ +#Domains= +#LLMNR=yes +#DNSSEC=@DEFAULT_DNSSEC_MODE@ +#Cache=yes +#DNSStubListener=udp diff --git a/src/grp-resolve/systemd-resolved/resolved.conf.xml b/src/grp-resolve/systemd-resolved/resolved.conf.xml new file mode 100644 index 0000000000..4fc1ef1b33 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/resolved.conf.xml @@ -0,0 +1,242 @@ +<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*--> +<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" + "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> + +<!-- + This file is part of systemd. + + Copyright 2014 Tom Gundersen + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +--> + +<refentry id="resolved.conf" conditional='ENABLE_RESOLVED' + xmlns:xi="http://www.w3.org/2001/XInclude"> + <refentryinfo> + <title>resolved.conf</title> + <productname>systemd</productname> + + <authorgroup> + <author> + <contrib>Developer</contrib> + <firstname>Tom</firstname> + <surname>Gundersen</surname> + <email>teg@jklm.no</email> + </author> + </authorgroup> + </refentryinfo> + + <refmeta> + <refentrytitle>resolved.conf</refentrytitle> + <manvolnum>5</manvolnum> + </refmeta> + + <refnamediv> + <refname>resolved.conf</refname> + <refname>resolved.conf.d</refname> + <refpurpose>Network Name Resolution configuration files</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <para><filename>/etc/systemd/resolved.conf</filename></para> + <para><filename>/etc/systemd/resolved.conf.d/*.conf</filename></para> + <para><filename>/run/systemd/resolved.conf.d/*.conf</filename></para> + <para><filename>/usr/lib/systemd/resolved.conf.d/*.conf</filename></para> + </refsynopsisdiv> + + <refsect1> + <title>Description</title> + + <para>These configuration files control local DNS and LLMNR + name resolution.</para> + + </refsect1> + + <xi:include href="standard-conf.xml" xpointer="main-conf" /> + + <refsect1> + <title>Options</title> + + <para>The following options are available in the <literal>[Resolve]</literal> section:</para> + + <variablelist class='network-directives'> + + <varlistentry> + <term><varname>DNS=</varname></term> + <listitem><para>A space-separated list of IPv4 and IPv6 addresses to use as system DNS servers. DNS requests + are sent to one of the listed DNS servers in parallel to suitable per-link DNS servers acquired from + <citerefentry><refentrytitle>systemd-networkd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> or + set at runtime by external applications. For compatibility reasons, if this setting is not specified, the DNS + servers listed in <filename>/etc/resolv.conf</filename> are used instead, if that file exists and any servers + are configured in it. This setting defaults to the empty list.</para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>FallbackDNS=</varname></term> + <listitem><para>A space-separated list of IPv4 and IPv6 addresses to use as the fallback DNS servers. Any + per-link DNS servers obtained from + <citerefentry><refentrytitle>systemd-networkd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> + take precedence over this setting, as do any servers set via <varname>DNS=</varname> above or + <filename>/etc/resolv.conf</filename>. This setting is hence only used if no other DNS server information is + known. If this option is not given, a compiled-in list of DNS servers is used instead.</para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>Domains=</varname></term> + <listitem><para>A space-separated list of domains. These domains are used as search suffixes when resolving + single-label host names (domain names which contain no dot), in order to qualify them into fully-qualified + domain names (FQDNs). Search domains are strictly processed in the order they are specified, until the name + with the suffix appended is found. For compatibility reasons, if this setting is not specified, the search + domains listed in <filename>/etc/resolv.conf</filename> are used instead, if that file exists and any domains + are configured in it. This setting defaults to the empty list.</para> + + <para>Specified domain names may optionally be prefixed with <literal>~</literal>. In this case they do not + define a search path, but preferably direct DNS queries for the indicated domains to the DNS servers configured + with the system <varname>DNS=</varname> setting (see above), in case additional, suitable per-link DNS servers + are known. If no per-link DNS servers are known using the <literal>~</literal> syntax has no effect. Use the + construct <literal>~.</literal> (which is composed of <literal>~</literal> to indicate a routing domain and + <literal>.</literal> to indicate the DNS root domain that is the implied suffix of all DNS domains) to use the + system DNS server defined with <varname>DNS=</varname> preferably for all domains.</para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>LLMNR=</varname></term> + <listitem><para>Takes a boolean argument or + <literal>resolve</literal>. Controls Link-Local Multicast Name + Resolution support (<ulink + url="https://tools.ietf.org/html/rfc4795">RFC 4794</ulink>) on + the local host. If true, enables full LLMNR responder and + resolver support. If false, disables both. If set to + <literal>resolve</literal>, only resolution support is enabled, + but responding is disabled. Note that + <citerefentry><refentrytitle>systemd-networkd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> + also maintains per-link LLMNR settings. LLMNR will be + enabled on a link only if the per-link and the + global setting is on.</para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>DNSSEC=</varname></term> + <listitem><para>Takes a boolean argument or + <literal>allow-downgrade</literal>. If true all DNS lookups are + DNSSEC-validated locally (excluding LLMNR and Multicast + DNS). If the response to a lookup request is detected to be invalid + a lookup failure is returned to applications. Note that + this mode requires a DNS server that supports DNSSEC. If the + DNS server does not properly support DNSSEC all validations + will fail. If set to <literal>allow-downgrade</literal> DNSSEC + validation is attempted, but if the server does not support + DNSSEC properly, DNSSEC mode is automatically disabled. Note + that this mode makes DNSSEC validation vulnerable to + "downgrade" attacks, where an attacker might be able to + trigger a downgrade to non-DNSSEC mode by synthesizing a DNS + response that suggests DNSSEC was not supported. If set to + false, DNS lookups are not DNSSEC validated.</para> + + <para>Note that DNSSEC validation requires retrieval of + additional DNS data, and thus results in a small DNS look-up + time penalty.</para> + + <para>DNSSEC requires knowledge of "trust anchors" to prove + data integrity. The trust anchor for the Internet root domain + is built into the resolver, additional trust anchors may be + defined with + <citerefentry><refentrytitle>dnssec-trust-anchors.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>. + Trust anchors may change at regular intervals, and old trust + anchors may be revoked. In such a case DNSSEC validation is + not possible until new trust anchors are configured locally or + the resolver software package is updated with the new root + trust anchor. In effect, when the built-in trust anchor is + revoked and <varname>DNSSEC=</varname> is true, all further + lookups will fail, as it cannot be proved anymore whether + lookups are correctly signed, or validly unsigned. If + <varname>DNSSEC=</varname> is set to + <literal>allow-downgrade</literal> the resolver will + automatically turn off DNSSEC validation in such a case.</para> + + <para>Client programs looking up DNS data will be informed + whether lookups could be verified using DNSSEC, or whether the + returned data could not be verified (either because the data + was found unsigned in the DNS, or the DNS server did not + support DNSSEC or no appropriate trust anchors were known). In + the latter case it is assumed that client programs employ a + secondary scheme to validate the returned DNS data, should + this be required.</para> + + <para>It is recommended to set <varname>DNSSEC=</varname> to + true on systems where it is known that the DNS server supports + DNSSEC correctly, and where software or trust anchor updates + happen regularly. On other systems it is recommended to set + <varname>DNSSEC=</varname> to + <literal>allow-downgrade</literal>.</para> + + <para>In addition to this global DNSSEC setting + <citerefentry><refentrytitle>systemd-networkd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> + also maintains per-link DNSSEC settings. For system DNS + servers (see above), only the global DNSSEC setting is in + effect. For per-link DNS servers the per-link + setting is in effect, unless it is unset in which case the + global setting is used instead.</para> + + <para>Site-private DNS zones generally conflict with DNSSEC + operation, unless a negative (if the private zone is not + signed) or positive (if the private zone is signed) trust + anchor is configured for them. If + <literal>allow-downgrade</literal> mode is selected, it is + attempted to detect site-private DNS zones using top-level + domains (TLDs) that are not known by the DNS root server. This + logic does not work in all private zone setups.</para> + + <para>Defaults to off.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Cache=</varname></term> + <listitem><para>Takes a boolean argument. If "yes" (the default), resolving a domain name which already got + queried earlier will return the previous result as long as it is still valid, and thus does not result in a new + network request. Be aware that turning off caching comes at a performance penalty, which is particularly + high when DNSSEC is used.</para> + + <para>Note that caching is turned off implicitly if the configured DNS server is on a host-local IP address + (such as 127.0.0.1 or ::1), in order to avoid duplicate local caching.</para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>DNSStubListener=</varname></term> + <listitem><para>Takes a boolean argument or one of <literal>udp</literal> and <literal>tcp</literal>. If + <literal>udp</literal> (the default), a DNS stub resolver will listen for UDP requests on address 127.0.0.53 + port 53. If <literal>tcp</literal>, the stub will listen for TCP requests on the same address and port. If + <literal>yes</literal>, the stub listens for both UDP and TCP requests. If <literal>no</literal>, the stub + listener is disabled.</para> + + <para>Note that the DNS stub listener is turned off implicitly when its listening address and port are already + in use.</para></listitem> + </varlistentry> + + </variablelist> + </refsect1> + + <refsect1> + <title>See Also</title> + <para> + <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd-networkd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, + <citerefentry><refentrytitle>dnssec-trust-anchors.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + <citerefentry project='man-pages'><refentrytitle>resolv.conf</refentrytitle><manvolnum>4</manvolnum></citerefentry> + </para> + </refsect1> + +</refentry> diff --git a/src/grp-resolve/systemd-resolved/systemd-resolved.service.m4.in b/src/grp-resolve/systemd-resolved/systemd-resolved.service.m4.in new file mode 100644 index 0000000000..0f0440ddaf --- /dev/null +++ b/src/grp-resolve/systemd-resolved/systemd-resolved.service.m4.in @@ -0,0 +1,40 @@ +# This file is part of systemd. +# +# systemd is free software; you can redistribute it and/or modify it +# under the terms of the GNU Lesser General Public License as published by +# the Free Software Foundation; either version 2.1 of the License, or +# (at your option) any later version. + +[Unit] +Description=Network Name Resolution +Documentation=man:systemd-resolved.service(8) +Documentation=http://www.freedesktop.org/wiki/Software/systemd/resolved +Documentation=http://www.freedesktop.org/wiki/Software/systemd/writing-network-configuration-managers +Documentation=http://www.freedesktop.org/wiki/Software/systemd/writing-resolver-clients +After=systemd-networkd.service network.target + +# On kdbus systems we pull in the busname explicitly, because it +# carries policy that allows the daemon to acquire its name. +Wants=org.freedesktop.resolve1.busname +After=org.freedesktop.resolve1.busname + +[Service] +Type=notify +Restart=always +RestartSec=0 +ExecStart=@rootlibexecdir@/systemd-resolved +WatchdogSec=3min +CapabilityBoundingSet=CAP_SETUID CAP_SETGID CAP_SETPCAP CAP_CHOWN CAP_DAC_OVERRIDE CAP_FOWNER CAP_NET_RAW CAP_NET_BIND_SERVICE +PrivateTmp=yes +PrivateDevices=yes +ProtectSystem=full +ProtectHome=yes +ProtectControlGroups=yes +ProtectKernelTunables=yes +MemoryDenyWriteExecute=yes +RestrictRealtime=yes +RestrictAddressFamilies=AF_UNIX AF_NETLINK AF_INET AF_INET6 +SystemCallFilter=~@clock @cpu-emulation @debug @keyring @module @mount @obsolete @raw-io + +[Install] +WantedBy=multi-user.target diff --git a/src/grp-resolve/systemd-resolved/systemd-resolved.service.xml b/src/grp-resolve/systemd-resolved/systemd-resolved.service.xml new file mode 100644 index 0000000000..56f67960ce --- /dev/null +++ b/src/grp-resolve/systemd-resolved/systemd-resolved.service.xml @@ -0,0 +1,234 @@ +<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*--> +<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" + "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> + +<!-- + This file is part of systemd. + + Copyright 2014 Tom Gundersen + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +--> + +<refentry id="systemd-resolved.service" conditional='ENABLE_RESOLVED'> + + <refentryinfo> + <title>systemd-resolved.service</title> + <productname>systemd</productname> + + <authorgroup> + <author> + <contrib>Developer</contrib> + <firstname>Tom</firstname> + <surname>Gundersen</surname> + <email>teg@jklm.no</email> + </author> + </authorgroup> + </refentryinfo> + + <refmeta> + <refentrytitle>systemd-resolved.service</refentrytitle> + <manvolnum>8</manvolnum> + </refmeta> + + <refnamediv> + <refname>systemd-resolved.service</refname> + <refname>systemd-resolved</refname> + <refpurpose>Network Name Resolution manager</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <para><filename>systemd-resolved.service</filename></para> + <para><filename>/usr/lib/systemd/systemd-resolved</filename></para> + </refsynopsisdiv> + + <refsect1> + <title>Description</title> + + <para><command>systemd-resolved</command> is a system service that provides network name resolution to local + applications. It implements a caching and validating DNS/DNSSEC stub resolver, as well as an LLMNR resolver and + responder. Local applications may submit network name resolution requests via three interfaces:</para> + + <itemizedlist> + <listitem><para>The native, fully-featured API <command>systemd-resolved</command> exposes on the bus. See the + <ulink url="http://www.freedesktop.org/wiki/Software/systemd/resolved">API Documentation</ulink> for + details. Usage of this API is generally recommended to clients as it is asynchronous and fully featured (for + example, properly returns DNSSEC validation status and interface scope for addresses as necessary for supporting + link-local networking).</para></listitem> + + <listitem><para>The glibc + <citerefentry project='man-pages'><refentrytitle>getaddrinfo</refentrytitle><manvolnum>3</manvolnum></citerefentry> API as defined + by <ulink url="https://tools.ietf.org/html/rfc3493">RFC3493</ulink> and its related resolver functions, + including <citerefentry project='man-pages'><refentrytitle>gethostbyname</refentrytitle><manvolnum>3</manvolnum></citerefentry>. This + API is widely supported, including beyond the Linux platform. In its current form it does not expose DNSSEC + validation status information however, and is synchronous only. This API is backed by the glibc Name Service + Switch (<citerefentry project='man-pages'><refentrytitle>nss</refentrytitle><manvolnum>5</manvolnum></citerefentry>). Usage of the + glibc NSS module <citerefentry><refentrytitle>nss-resolve</refentrytitle><manvolnum>8</manvolnum></citerefentry> + is required in order to allow glibc's NSS resolver functions to resolve host names via + <command>systemd-resolved</command>.</para></listitem> + + <listitem><para>Additionally, <command>systemd-resolved</command> provides a local DNS stub listener on IP + address 127.0.0.53 on the local loopback interface. Programs issuing DNS requests directly, bypassing any local + API may be directed to this stub, in order to connect them to <command>systemd-resolved</command>. Note however + that it is strongly recommended that local programs use the glibc NSS or bus APIs instead (as described above), + as various network resolution concepts (such as link-local addressing, or LLMNR Unicode domains) cannot be mapped + to the unicast DNS protocol.</para></listitem> + </itemizedlist> + + <para>The DNS servers contacted are determined from the global settings in + <filename>/etc/systemd/resolved.conf</filename>, the per-link static settings in + <filename>/etc/systemd/network/*.network</filename> files, the per-link dynamic settings received over DHCP and any + DNS server information made available by other system services. See + <citerefentry><refentrytitle>resolved.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> and + <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry> for details + about systemd's own configuration files for DNS servers. To improve compatibility, + <filename>/etc/resolv.conf</filename> is read in order to discover configured system DNS servers, but only if it is + not a symlink to <filename>/run/systemd/resolve/resolv.conf</filename> (see below).</para> + + <para><command>systemd-resolved</command> synthesizes DNS resource records (RRs) for the following cases:</para> + + <itemizedlist> + <listitem><para>The local, configured hostname is resolved to + all locally configured IP addresses ordered by their scope, or + — if none are configured — the IPv4 address 127.0.0.2 (which + is on the local loopback) and the IPv6 address ::1 (which is the + local host).</para></listitem> + + <listitem><para>The hostnames <literal>localhost</literal> and + <literal>localhost.localdomain</literal> (as well as any hostname + ending in <literal>.localhost</literal> or <literal>.localhost.localdomain</literal>) + are resolved to the IP addresses 127.0.0.1 and ::1.</para></listitem> + + <listitem><para>The hostname <literal>gateway</literal> is + resolved to all current default routing gateway addresses, + ordered by their metric. This assigns a stable hostname to the + current gateway, useful for referencing it independently of the + current network configuration state.</para></listitem> + + <listitem><para>The mappings defined in <filename>/etc/hosts</filename> are resolved to their configured + addresses and back.</para></listitem> + </itemizedlist> + + <para>Lookup requests are routed to the available DNS servers + and LLMNR interfaces according to the following rules:</para> + + <itemizedlist> + <listitem><para>Lookups for the special hostname + <literal>localhost</literal> are never routed to the + network. (A few other, special domains are handled the same way.)</para></listitem> + + <listitem><para>Single-label names are routed to all local + interfaces capable of IP multicasting, using the LLMNR + protocol. Lookups for IPv4 addresses are only sent via LLMNR on + IPv4, and lookups for IPv6 addresses are only sent via LLMNR on + IPv6. Lookups for the locally configured host name and the + <literal>gateway</literal> host name are never routed to + LLMNR.</para></listitem> + + <listitem><para>Multi-label names are routed to all local + interfaces that have a DNS sever configured, plus the globally + configured DNS server if there is one. Address lookups from the + link-local address range are never routed to + DNS.</para></listitem> + </itemizedlist> + + <para>If lookups are routed to multiple interfaces, the first + successful response is returned (thus effectively merging the + lookup zones on all matching interfaces). If the lookup failed on + all interfaces, the last failing response is returned.</para> + + <para>Routing of lookups may be influenced by configuring + per-interface domain names. See + <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry> + for details. Lookups for a hostname ending in one of the + per-interface domains are exclusively routed to the matching + interfaces.</para> + + <para>See the <ulink url="http://www.freedesktop.org/wiki/Software/systemd/resolved"> resolved D-Bus API + Documentation</ulink> for information about the APIs <filename>systemd-resolved</filename> provides.</para> + + </refsect1> + + <refsect1> + <title><filename>/etc/resolv.conf</filename></title> + + <para>Three modes of handling <filename>/etc/resolv.conf</filename> (see + <citerefentry project='man-pages'><refentrytitle>resolv.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>) are + supported:</para> + + <itemizedlist> + <listitem><para>A static file <filename>/usr/lib/systemd/resolv.conf</filename> is provided that lists + the 127.0.0.53 DNS stub (see above) as only DNS server. This file may be symlinked from + <filename>/etc/resolv.conf</filename> in order to connect all local clients that bypass local DNS APIs to + <command>systemd-resolved</command>. This mode of operation is recommended.</para></listitem> + + <listitem><para><command>systemd-resolved</command> maintains the + <filename>/run/systemd/resolve/resolv.conf</filename> file for compatibility with traditional Linux + programs. This file may be symlinked from <filename>/etc/resolv.conf</filename> and is always kept up-to-date, + containing information about all known DNS servers. Note the file format's limitations: it does not know a + concept of per-interface DNS servers and hence only contains system-wide DNS server definitions. Note that + <filename>/run/systemd/resolve/resolv.conf</filename> should not be used directly by applications, but only + through a symlink from <filename>/etc/resolv.conf</filename>. If this mode of operation is used local clients + that bypass any local DNS API will also bypass <command>systemd-resolved</command> and will talk directly to the + known DNS servers.</para> </listitem> + + <listitem><para>Alternatively, <filename>/etc/resolv.conf</filename> may be managed by other packages, in which + case <command>systemd-resolved</command> will read it for DNS configuration data. In this mode of operation + <command>systemd-resolved</command> is consumer rather than provider of this configuration + file. </para></listitem> + </itemizedlist> + + <para>Note that the selected mode of operation for this file is detected fully automatically, depending on whether + <filename>/etc/resolv.conf</filename> is a symlink to <filename>/run/systemd/resolve/resolv.conf</filename> or + lists 127.0.0.53 as DNS server.</para> + </refsect1> + + <refsect1> + <title>Signals</title> + + <variablelist> + <varlistentry> + <term><constant>SIGUSR1</constant></term> + + <listitem><para>Upon reception of the SIGUSR1 process signal <command>systemd-resolved</command> will dump the + contents of all DNS resource record caches it maintains into the system logs.</para></listitem> + </varlistentry> + + <varlistentry> + <term><constant>SIGUSR2</constant></term> + + <listitem><para>Upon reception of the SIGUSR2 process signal <command>systemd-resolved</command> will flush all + caches it maintains. Note that it should normally not be necessary to request this explicitly – except for + debugging purposes – as <command>systemd-resolved</command> flushes the caches automatically anyway any time + the host's network configuration changes.</para></listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>See Also</title> + <para> + <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, + <citerefentry><refentrytitle>resolved.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + <citerefentry><refentrytitle>dnssec-trust-anchors.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + <citerefentry><refentrytitle>nss-resolve</refentrytitle><manvolnum>8</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd-resolve</refentrytitle><manvolnum>1</manvolnum></citerefentry>, + <citerefentry project='man-pages'><refentrytitle>resolv.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + <citerefentry project='man-pages'><refentrytitle>hosts</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd-networkd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> + </para> + </refsect1> + +</refentry> diff --git a/src/grp-resolve/systemd-resolved/systemd-resolved.sysusers b/src/grp-resolve/systemd-resolved/systemd-resolved.sysusers new file mode 100644 index 0000000000..5872bf2db7 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/systemd-resolved.sysusers @@ -0,0 +1,8 @@ +# This file is part of systemd. +# +# systemd is free software; you can redistribute it and/or modify it +# under the terms of the GNU Lesser General Public License as published by +# the Free Software Foundation; either version 2.1 of the License, or +# (at your option) any later version. + +u systemd-resolve - "systemd Resolver" diff --git a/src/grp-resolve/systemd-resolved/systemd-resolved.tmpfiles b/src/grp-resolve/systemd-resolved/systemd-resolved.tmpfiles new file mode 100644 index 0000000000..760fe11412 --- /dev/null +++ b/src/grp-resolve/systemd-resolved/systemd-resolved.tmpfiles @@ -0,0 +1,10 @@ +# This file is part of systemd. +# +# systemd is free software; you can redistribute it and/or modify it +# under the terms of the GNU Lesser General Public License as published by +# the Free Software Foundation; either version 2.1 of the License, or +# (at your option) any later version. + +# See tmpfiles.d(5) for details + +L! /etc/resolv.conf - - - - ../usr/lib/systemd/resolv.conf |