./tools/notsd-move

29 files changed, 10061 insertions, 0 deletions

diff --git a/src/grp-resolve/libbasic-dns/Makefile b/src/grp-resolve/libbasic-dns/Makefile
new file mode 100644
index 0000000000..40ee1e85b5
--- /dev/null
+++ b/src/grp-resolve/libbasic-dns/Makefile
@@ -0,0 +1,109 @@
+#  -*- 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 $(topsrcdir)/build-aux/Makefile.head.mk
+
+$(outdir)/dns_type-list.txt: src/resolve/dns-type.h
+	$(AM_V_GEN)$(SED) -n -r 's/.* DNS_TYPE_(\w+).*/\1/p' <$< >$@
+
+$(outdir)/dns_type-to-name.h: src/resolve/dns_type-list.txt
+	$(AM_V_GEN)$(AWK) 'BEGIN{ print "const char *dns_type_to_string(int type) {\n\tswitch(type) {" } {printf "        case DNS_TYPE_%s: return ", $$1; sub(/_/, "-"); printf "\"%s\";\n", $$1 } END{ print "        default: return NULL;\n\t}\n}\n" }' <$< >$@
+
+$(outdir)/dns_type-from-name.gperf: src/resolve/dns_type-list.txt
+	$(AM_V_GEN)$(AWK) 'BEGIN{ print "struct dns_type_name { const char* name; int id; };"; print "%null-strings"; print "%%";} { s=$$1; sub(/_/, "-", s); printf "%s, ", $$s; printf "DNS_TYPE_%s\n", $$1 }' <$< >$@
+
+tests += \
+	test-dns-packet \
+	test-resolve-tables \
+	test-dnssec
+
+manual_tests += \
+	test-dnssec-complex
+
+test_resolve_tables_SOURCES = \
+	src/resolve/test-resolve-tables.c \
+	src/resolve/dns_type-from-name.h \
+	src/resolve/dns_type-to-name.h \
+	$(basic_dns_sources) \
+	src/shared/test-tables.h
+
+test_resolve_tables_CFLAGS = \
+	$(GCRYPT_CFLAGS)
+
+test_resolve_tables_LDADD = \
+	libsystemd-shared.la \
+	$(GCRYPT_LIBS) \
+	-lm
+
+test_dns_packet_SOURCES = \
+	src/resolve/test-dns-packet.c \
+	$(basic_dns_sources)
+
+test_dns_packet_CPPFLAGS = \
+	-DRESOLVE_TEST_DIR=\"$(abs_top_srcdir)/src/resolve/test-data\"
+
+test_dns_packet_CFLAGS = \
+	$(GCRYPT_CFLAGS)
+
+test_dns_packet_LDADD = \
+	libsystemd-shared.la \
+	$(GCRYPT_LIBS) \
+	-lm
+
+EXTRA_DIST += \
+	src/resolve/test-data/_openpgpkey.fedoraproject.org.pkts \
+	src/resolve/test-data/fedoraproject.org.pkts \
+	src/resolve/test-data/gandi.net.pkts \
+	src/resolve/test-data/google.com.pkts \
+	src/resolve/test-data/root.pkts \
+	src/resolve/test-data/sw1a1aa-sw1a2aa-sw1a2ab-sw1a2ac.find.me.uk.pkts \
+	src/resolve/test-data/teamits.com.pkts \
+	src/resolve/test-data/zbyszek@fedoraproject.org.pkts \
+	src/resolve/test-data/_443._tcp.fedoraproject.org.pkts \
+	src/resolve/test-data/kyhwana.org.pkts \
+	src/resolve/test-data/fake-caa.pkts
+
+test_dnssec_SOURCES = \
+	src/resolve/test-dnssec.c \
+	$(basic_dns_sources)
+
+test_dnssec_CFLAGS = \
+	$(GCRYPT_CFLAGS)
+
+test_dnssec_LDADD = \
+	libsystemd-shared.la \
+	$(GCRYPT_LIBS) \
+	-lm
+
+test_dnssec_complex_SOURCES = \
+	src/resolve/test-dnssec-complex.c \
+	src/resolve/dns-type.c \
+	src/resolve/dns-type.h
+
+test_dnssec_complex_LDADD = \
+	libsystemd-shared.la
+
+gperf_txt_sources += \
+	src/resolve/dns_type-list.txt
+
+include $(topsrcdir)/build-aux/Makefile.tail.mk
diff --git a/src/grp-resolve/libbasic-dns/include/basic-dns/dns-type.h b/src/grp-resolve/libbasic-dns/include/basic-dns/dns-type.h
new file mode 100644
index 0000000000..df1642f85e
--- /dev/null
+++ b/src/grp-resolve/libbasic-dns/include/basic-dns/dns-type.h
@@ -0,0 +1,162 @@
+#pragma once
+
+/***
+  This file is part of systemd.
+
+  Copyright 2014 Zbigniew Jędrzejewski-Szmek
+
+  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"
+
+/* DNS record types, taken from
+ * http://www.iana.org/assignments/dns-parameters/dns-parameters.xhtml.
+ */
+enum {
+        /* Normal records */
+        DNS_TYPE_A          = 0x01,
+        DNS_TYPE_NS,
+        DNS_TYPE_MD,
+        DNS_TYPE_MF,
+        DNS_TYPE_CNAME,
+        DNS_TYPE_SOA,
+        DNS_TYPE_MB,
+        DNS_TYPE_MG,
+        DNS_TYPE_MR,
+        DNS_TYPE_NULL,
+        DNS_TYPE_WKS,
+        DNS_TYPE_PTR,
+        DNS_TYPE_HINFO,
+        DNS_TYPE_MINFO,
+        DNS_TYPE_MX,
+        DNS_TYPE_TXT,
+        DNS_TYPE_RP,
+        DNS_TYPE_AFSDB,
+        DNS_TYPE_X25,
+        DNS_TYPE_ISDN,
+        DNS_TYPE_RT,
+        DNS_TYPE_NSAP,
+        DNS_TYPE_NSAP_PTR,
+        DNS_TYPE_SIG,
+        DNS_TYPE_KEY,
+        DNS_TYPE_PX,
+        DNS_TYPE_GPOS,
+        DNS_TYPE_AAAA,
+        DNS_TYPE_LOC,
+        DNS_TYPE_NXT,
+        DNS_TYPE_EID,
+        DNS_TYPE_NIMLOC,
+        DNS_TYPE_SRV,
+        DNS_TYPE_ATMA,
+        DNS_TYPE_NAPTR,
+        DNS_TYPE_KX,
+        DNS_TYPE_CERT,
+        DNS_TYPE_A6,
+        DNS_TYPE_DNAME,
+        DNS_TYPE_SINK,
+        DNS_TYPE_OPT,          /* EDNS0 option */
+        DNS_TYPE_APL,
+        DNS_TYPE_DS,
+        DNS_TYPE_SSHFP,
+        DNS_TYPE_IPSECKEY,
+        DNS_TYPE_RRSIG,
+        DNS_TYPE_NSEC,
+        DNS_TYPE_DNSKEY,
+        DNS_TYPE_DHCID,
+        DNS_TYPE_NSEC3,
+        DNS_TYPE_NSEC3PARAM,
+        DNS_TYPE_TLSA,
+
+        DNS_TYPE_HIP        = 0x37,
+        DNS_TYPE_NINFO,
+        DNS_TYPE_RKEY,
+        DNS_TYPE_TALINK,
+        DNS_TYPE_CDS,
+        DNS_TYPE_CDNSKEY,
+        DNS_TYPE_OPENPGPKEY,
+
+        DNS_TYPE_SPF        = 0x63,
+        DNS_TYPE_NID,
+        DNS_TYPE_L32,
+        DNS_TYPE_L64,
+        DNS_TYPE_LP,
+        DNS_TYPE_EUI48,
+        DNS_TYPE_EUI64,
+
+        DNS_TYPE_TKEY       = 0xF9,
+        DNS_TYPE_TSIG,
+        DNS_TYPE_IXFR,
+        DNS_TYPE_AXFR,
+        DNS_TYPE_MAILB,
+        DNS_TYPE_MAILA,
+        DNS_TYPE_ANY,
+        DNS_TYPE_URI,
+        DNS_TYPE_CAA,
+        DNS_TYPE_TA         = 0x8000,
+        DNS_TYPE_DLV,
+
+        _DNS_TYPE_MAX,
+        _DNS_TYPE_INVALID = -1
+};
+
+assert_cc(DNS_TYPE_SSHFP == 44);
+assert_cc(DNS_TYPE_TLSA == 52);
+assert_cc(DNS_TYPE_ANY == 255);
+
+/* DNS record classes, see RFC 1035 */
+enum {
+        DNS_CLASS_IN   = 0x01,
+        DNS_CLASS_ANY  = 0xFF,
+
+        _DNS_CLASS_MAX,
+        _DNS_CLASS_INVALID = -1
+};
+
+#define _DNS_CLASS_STRING_MAX (sizeof "CLASS" + DECIMAL_STR_MAX(uint16_t))
+#define _DNS_TYPE_STRING_MAX (sizeof "CLASS" + DECIMAL_STR_MAX(uint16_t))
+
+bool dns_type_is_pseudo(uint16_t type);
+bool dns_type_is_valid_query(uint16_t type);
+bool dns_type_is_valid_rr(uint16_t type);
+bool dns_type_may_redirect(uint16_t type);
+bool dns_type_is_dnssec(uint16_t type);
+bool dns_type_is_obsolete(uint16_t type);
+bool dns_type_may_wildcard(uint16_t type);
+bool dns_type_apex_only(uint16_t type);
+bool dns_type_needs_authentication(uint16_t type);
+bool dns_type_is_zone_transer(uint16_t type);
+int dns_type_to_af(uint16_t type);
+
+bool dns_class_is_pseudo(uint16_t class);
+bool dns_class_is_valid_rr(uint16_t class);
+
+/* TYPE?? follows http://tools.ietf.org/html/rfc3597#section-5 */
+const char *dns_type_to_string(int type);
+int dns_type_from_string(const char *s);
+
+const char *dns_class_to_string(uint16_t class);
+int dns_class_from_string(const char *name);
+
+/* https://tools.ietf.org/html/draft-ietf-dane-protocol-23#section-7.2 */
+const char *tlsa_cert_usage_to_string(uint8_t cert_usage);
+
+/* https://tools.ietf.org/html/draft-ietf-dane-protocol-23#section-7.3 */
+const char *tlsa_selector_to_string(uint8_t selector);
+
+/* https://tools.ietf.org/html/draft-ietf-dane-protocol-23#section-7.4 */
+const char *tlsa_matching_type_to_string(uint8_t selector);
+
+/* https://tools.ietf.org/html/rfc6844#section-5.1 */
+#define CAA_FLAG_CRITICAL (1u << 7)
diff --git a/src/grp-resolve/libbasic-dns/include/basic-dns/resolved-def.h b/src/grp-resolve/libbasic-dns/include/basic-dns/resolved-def.h
new file mode 100644
index 0000000000..c4c1915b18
--- /dev/null
+++ b/src/grp-resolve/libbasic-dns/include/basic-dns/resolved-def.h
@@ -0,0 +1,38 @@
+#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 <inttypes.h>
+
+#define SD_RESOLVED_DNS           (UINT64_C(1) << 0)
+#define SD_RESOLVED_LLMNR_IPV4    (UINT64_C(1) << 1)
+#define SD_RESOLVED_LLMNR_IPV6    (UINT64_C(1) << 2)
+#define SD_RESOLVED_MDNS_IPV4     (UINT64_C(1) << 3)
+#define SD_RESOLVED_MDNS_IPV6     (UINT64_C(1) << 4)
+#define SD_RESOLVED_NO_CNAME      (UINT64_C(1) << 5)
+#define SD_RESOLVED_NO_TXT        (UINT64_C(1) << 6)
+#define SD_RESOLVED_NO_ADDRESS    (UINT64_C(1) << 7)
+#define SD_RESOLVED_NO_SEARCH     (UINT64_C(1) << 8)
+#define SD_RESOLVED_AUTHENTICATED (UINT64_C(1) << 9)
+
+#define SD_RESOLVED_LLMNR         (SD_RESOLVED_LLMNR_IPV4|SD_RESOLVED_LLMNR_IPV6)
+#define SD_RESOLVED_MDNS          (SD_RESOLVED_MDNS_IPV4|SD_RESOLVED_MDNS_IPV6)
+
+#define SD_RESOLVED_PROTOCOLS_ALL (SD_RESOLVED_MDNS|SD_RESOLVED_LLMNR|SD_RESOLVED_DNS)
diff --git a/src/grp-resolve/libbasic-dns/include/basic-dns/resolved-dns-answer.h b/src/grp-resolve/libbasic-dns/include/basic-dns/resolved-dns-answer.h
new file mode 100644
index 0000000000..447604d008
--- /dev/null
+++ b/src/grp-resolve/libbasic-dns/include/basic-dns/resolved-dns-answer.h
@@ -0,0 +1,148 @@
+#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/macro.h"
+
+typedef struct DnsAnswer DnsAnswer;
+typedef struct DnsAnswerItem DnsAnswerItem;
+
+#include "resolved-dns-rr.h"
+
+/* A simple array of resource records. We keep track of the
+ * originating ifindex for each RR where that makes sense, so that we
+ * can qualify A and AAAA RRs referring to a local link with the
+ * right ifindex.
+ *
+ * Note that we usually encode the empty DnsAnswer object as a simple NULL. */
+
+typedef enum DnsAnswerFlags {
+        DNS_ANSWER_AUTHENTICATED = 1, /* Item has been authenticated */
+        DNS_ANSWER_CACHEABLE     = 2, /* Item is subject to caching */
+        DNS_ANSWER_SHARED_OWNER  = 4, /* For mDNS: RRset may be owner by multiple peers */
+} DnsAnswerFlags;
+
+struct DnsAnswerItem {
+        DnsResourceRecord *rr;
+        int ifindex;
+        DnsAnswerFlags flags;
+};
+
+struct DnsAnswer {
+        unsigned n_ref;
+        unsigned n_rrs, n_allocated;
+        DnsAnswerItem items[0];
+};
+
+DnsAnswer *dns_answer_new(unsigned n);
+DnsAnswer *dns_answer_ref(DnsAnswer *a);
+DnsAnswer *dns_answer_unref(DnsAnswer *a);
+
+int dns_answer_add(DnsAnswer *a, DnsResourceRecord *rr, int ifindex, DnsAnswerFlags flags);
+int dns_answer_add_extend(DnsAnswer **a, DnsResourceRecord *rr, int ifindex, DnsAnswerFlags flags);
+int dns_answer_add_soa(DnsAnswer *a, const char *name, uint32_t ttl, int ifindex);
+
+int dns_answer_match_key(DnsAnswer *a, const DnsResourceKey *key, DnsAnswerFlags *combined_flags);
+int dns_answer_contains_rr(DnsAnswer *a, DnsResourceRecord *rr, DnsAnswerFlags *combined_flags);
+int dns_answer_contains_key(DnsAnswer *a, const DnsResourceKey *key, DnsAnswerFlags *combined_flags);
+int dns_answer_contains_nsec_or_nsec3(DnsAnswer *a);
+int dns_answer_contains_zone_nsec3(DnsAnswer *answer, const char *zone);
+
+int dns_answer_find_soa(DnsAnswer *a, const DnsResourceKey *key, DnsResourceRecord **ret, DnsAnswerFlags *flags);
+int dns_answer_find_cname_or_dname(DnsAnswer *a, const DnsResourceKey *key, DnsResourceRecord **ret, DnsAnswerFlags *flags);
+
+int dns_answer_merge(DnsAnswer *a, DnsAnswer *b, DnsAnswer **ret);
+int dns_answer_extend(DnsAnswer **a, DnsAnswer *b);
+
+void dns_answer_order_by_scope(DnsAnswer *a, bool prefer_link_local);
+
+int dns_answer_reserve(DnsAnswer **a, unsigned n_free);
+int dns_answer_reserve_or_clone(DnsAnswer **a, unsigned n_free);
+
+int dns_answer_remove_by_key(DnsAnswer **a, const DnsResourceKey *key);
+int dns_answer_remove_by_rr(DnsAnswer **a, DnsResourceRecord *rr);
+
+int dns_answer_copy_by_key(DnsAnswer **a, DnsAnswer *source, const DnsResourceKey *key, DnsAnswerFlags or_flags);
+int dns_answer_move_by_key(DnsAnswer **to, DnsAnswer **from, const DnsResourceKey *key, DnsAnswerFlags or_flags);
+
+bool dns_answer_has_dname_for_cname(DnsAnswer *a, DnsResourceRecord *cname);
+
+static inline unsigned dns_answer_size(DnsAnswer *a) {
+        return a ? a->n_rrs : 0;
+}
+
+static inline bool dns_answer_isempty(DnsAnswer *a) {
+        return dns_answer_size(a) <= 0;
+}
+
+void dns_answer_dump(DnsAnswer *answer, FILE *f);
+
+DEFINE_TRIVIAL_CLEANUP_FUNC(DnsAnswer*, dns_answer_unref);
+
+#define _DNS_ANSWER_FOREACH(q, kk, a)                                   \
+        for (unsigned UNIQ_T(i, q) = ({                                 \
+                                (kk) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].rr : NULL; \
+                                0;                                      \
+                        });                                             \
+             (a) && (UNIQ_T(i, q) < (a)->n_rrs);                        \
+             UNIQ_T(i, q)++, (kk) = (UNIQ_T(i, q) < (a)->n_rrs ? (a)->items[UNIQ_T(i, q)].rr : NULL))
+
+#define DNS_ANSWER_FOREACH(kk, a) _DNS_ANSWER_FOREACH(UNIQ, kk, a)
+
+#define _DNS_ANSWER_FOREACH_IFINDEX(q, kk, ifi, a)                      \
+        for (unsigned UNIQ_T(i, q) = ({                                 \
+                                (kk) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].rr : NULL; \
+                                (ifi) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].ifindex : 0; \
+                                0;                                      \
+                        });                                             \
+             (a) && (UNIQ_T(i, q) < (a)->n_rrs);                        \
+             UNIQ_T(i, q)++,                                            \
+                     (kk) = ((UNIQ_T(i, q) < (a)->n_rrs) ? (a)->items[UNIQ_T(i, q)].rr : NULL), \
+                     (ifi) = ((UNIQ_T(i, q) < (a)->n_rrs) ? (a)->items[UNIQ_T(i, q)].ifindex : 0))
+
+#define DNS_ANSWER_FOREACH_IFINDEX(kk, ifindex, a) _DNS_ANSWER_FOREACH_IFINDEX(UNIQ, kk, ifindex, a)
+
+#define _DNS_ANSWER_FOREACH_FLAGS(q, kk, fl, a)                         \
+        for (unsigned UNIQ_T(i, q) = ({                                 \
+                                (kk) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].rr : NULL; \
+                                (fl) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].flags : 0; \
+                                0;                                      \
+                        });                                             \
+             (a) && (UNIQ_T(i, q) < (a)->n_rrs);                        \
+             UNIQ_T(i, q)++,                                            \
+                     (kk) = ((UNIQ_T(i, q) < (a)->n_rrs) ? (a)->items[UNIQ_T(i, q)].rr : NULL), \
+                     (fl) = ((UNIQ_T(i, q) < (a)->n_rrs) ? (a)->items[UNIQ_T(i, q)].flags : 0))
+
+#define DNS_ANSWER_FOREACH_FLAGS(kk, flags, a) _DNS_ANSWER_FOREACH_FLAGS(UNIQ, kk, flags, a)
+
+#define _DNS_ANSWER_FOREACH_FULL(q, kk, ifi, fl, a)                     \
+        for (unsigned UNIQ_T(i, q) = ({                                 \
+                                (kk) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].rr : NULL; \
+                                (ifi) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].ifindex : 0; \
+                                (fl) = ((a) && (a)->n_rrs > 0) ? (a)->items[0].flags : 0; \
+                                0;                                      \
+                        });                                             \
+             (a) && (UNIQ_T(i, q) < (a)->n_rrs);                        \
+             UNIQ_T(i, q)++,                                            \
+                     (kk) = ((UNIQ_T(i, q) < (a)->n_rrs) ? (a)->items[UNIQ_T(i, q)].rr : NULL), \
+                     (ifi) = ((UNIQ_T(i, q) < (a)->n_rrs) ? (a)->items[UNIQ_T(i, q)].ifindex : 0), \
+                     (fl) = ((UNIQ_T(i, q) < (a)->n_rrs) ? (a)->items[UNIQ_T(i, q)].flags : 0))
+
+#define DNS_ANSWER_FOREACH_FULL(kk, ifindex, flags, a) _DNS_ANSWER_FOREACH_FULL(UNIQ, kk, ifindex, flags, a)
diff --git a/src/grp-resolve/libbasic-dns/include/basic-dns/resolved-dns-dnssec.h b/src/grp-resolve/libbasic-dns/include/basic-dns/resolved-dns-dnssec.h
new file mode 100644
index 0000000000..b91abe98ac
--- /dev/null
+++ b/src/grp-resolve/libbasic-dns/include/basic-dns/resolved-dns-dnssec.h
@@ -0,0 +1,103 @@
+#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-shared/dns-domain.h"
+
+typedef enum DnssecResult DnssecResult;
+typedef enum DnssecVerdict DnssecVerdict;
+
+#include "resolved-dns-answer.h"
+#include "resolved-dns-rr.h"
+
+enum DnssecResult {
+        /* These five are returned by dnssec_verify_rrset() */
+        DNSSEC_VALIDATED,
+        DNSSEC_VALIDATED_WILDCARD, /* Validated via a wildcard RRSIG, further NSEC/NSEC3 checks necessary */
+        DNSSEC_INVALID,
+        DNSSEC_SIGNATURE_EXPIRED,
+        DNSSEC_UNSUPPORTED_ALGORITHM,
+
+        /* These two are added by dnssec_verify_rrset_search() */
+        DNSSEC_NO_SIGNATURE,
+        DNSSEC_MISSING_KEY,
+
+        /* These two are added by the DnsTransaction logic */
+        DNSSEC_UNSIGNED,
+        DNSSEC_FAILED_AUXILIARY,
+        DNSSEC_NSEC_MISMATCH,
+        DNSSEC_INCOMPATIBLE_SERVER,
+
+        _DNSSEC_RESULT_MAX,
+        _DNSSEC_RESULT_INVALID = -1
+};
+
+enum DnssecVerdict {
+        DNSSEC_SECURE,
+        DNSSEC_INSECURE,
+        DNSSEC_BOGUS,
+        DNSSEC_INDETERMINATE,
+
+        _DNSSEC_VERDICT_MAX,
+        _DNSSEC_VERDICT_INVALID = -1
+};
+
+#define DNSSEC_CANONICAL_HOSTNAME_MAX (DNS_HOSTNAME_MAX + 2)
+
+/* The longest digest we'll ever generate, of all digest algorithms we support */
+#define DNSSEC_HASH_SIZE_MAX (MAX(20, 32))
+
+int dnssec_rrsig_match_dnskey(DnsResourceRecord *rrsig, DnsResourceRecord *dnskey, bool revoked_ok);
+int dnssec_key_match_rrsig(const DnsResourceKey *key, DnsResourceRecord *rrsig);
+
+int dnssec_verify_rrset(DnsAnswer *answer, const DnsResourceKey *key, DnsResourceRecord *rrsig, DnsResourceRecord *dnskey, usec_t realtime, DnssecResult *result);
+int dnssec_verify_rrset_search(DnsAnswer *answer, const DnsResourceKey *key, DnsAnswer *validated_dnskeys, usec_t realtime, DnssecResult *result, DnsResourceRecord **rrsig);
+
+int dnssec_verify_dnskey_by_ds(DnsResourceRecord *dnskey, DnsResourceRecord *ds, bool mask_revoke);
+int dnssec_verify_dnskey_by_ds_search(DnsResourceRecord *dnskey, DnsAnswer *validated_ds);
+
+int dnssec_has_rrsig(DnsAnswer *a, const DnsResourceKey *key);
+
+uint16_t dnssec_keytag(DnsResourceRecord *dnskey, bool mask_revoke);
+
+int dnssec_canonicalize(const char *n, char *buffer, size_t buffer_max);
+
+int dnssec_nsec3_hash(DnsResourceRecord *nsec3, const char *name, void *ret);
+
+typedef enum DnssecNsecResult {
+        DNSSEC_NSEC_NO_RR,     /* No suitable NSEC/NSEC3 RR found */
+        DNSSEC_NSEC_CNAME,     /* Didn't find what was asked for, but did find CNAME */
+        DNSSEC_NSEC_UNSUPPORTED_ALGORITHM,
+        DNSSEC_NSEC_NXDOMAIN,
+        DNSSEC_NSEC_NODATA,
+        DNSSEC_NSEC_FOUND,
+        DNSSEC_NSEC_OPTOUT,
+} DnssecNsecResult;
+
+int dnssec_nsec_test(DnsAnswer *answer, DnsResourceKey *key, DnssecNsecResult *result, bool *authenticated, uint32_t *ttl);
+
+
+int dnssec_test_positive_wildcard(DnsAnswer *a, const char *name, const char *source, const char *zone, bool *authenticated);
+
+const char* dnssec_result_to_string(DnssecResult m) _const_;
+DnssecResult dnssec_result_from_string(const char *s) _pure_;
+
+const char* dnssec_verdict_to_string(DnssecVerdict m) _const_;
+DnssecVerdict dnssec_verdict_from_string(const char *s) _pure_;
diff --git a/src/grp-resolve/libbasic-dns/include/basic-dns/resolved-dns-packet.h b/src/grp-resolve/libbasic-dns/include/basic-dns/resolved-dns-packet.h
new file mode 100644
index 0000000000..cb03de8986
--- /dev/null
+++ b/src/grp-resolve/libbasic-dns/include/basic-dns/resolved-dns-packet.h
@@ -0,0 +1,302 @@
+#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 <netinet/ip.h>
+#include <netinet/udp.h>
+
+#include "systemd-basic/hashmap.h"
+#include "systemd-basic/in-addr-util.h"
+#include "systemd-basic/macro.h"
+#include "systemd-basic/sparse-endian.h"
+
+typedef struct DnsPacket DnsPacket;
+typedef struct DnsPacketHeader DnsPacketHeader;
+
+#include "resolved-def.h"
+#include "resolved-dns-answer.h"
+#include "resolved-dns-question.h"
+#include "resolved-dns-rr.h"
+
+typedef enum DnsProtocol {
+        DNS_PROTOCOL_DNS,
+        DNS_PROTOCOL_MDNS,
+        DNS_PROTOCOL_LLMNR,
+        _DNS_PROTOCOL_MAX,
+        _DNS_PROTOCOL_INVALID = -1
+} DnsProtocol;
+
+struct DnsPacketHeader {
+        uint16_t id;
+        be16_t flags;
+        be16_t qdcount;
+        be16_t ancount;
+        be16_t nscount;
+        be16_t arcount;
+};
+
+#define DNS_PACKET_HEADER_SIZE sizeof(DnsPacketHeader)
+#define UDP_PACKET_HEADER_SIZE (sizeof(struct iphdr) + sizeof(struct udphdr))
+
+/* The various DNS protocols deviate in how large a packet can grow,
+   but the TCP transport has a 16bit size field, hence that appears to
+   be the absolute maximum. */
+#define DNS_PACKET_SIZE_MAX 0xFFFF
+
+/* RFC 1035 say 512 is the maximum, for classic unicast DNS */
+#define DNS_PACKET_UNICAST_SIZE_MAX 512
+
+/* With EDNS0 we can use larger packets, default to 4096, which is what is commonly used */
+#define DNS_PACKET_UNICAST_SIZE_LARGE_MAX 4096
+
+#define DNS_PACKET_SIZE_START 512
+
+struct DnsPacket {
+        int n_ref;
+        DnsProtocol protocol;
+        size_t size, allocated, rindex;
+        void *_data; /* don't access directly, use DNS_PACKET_DATA()! */
+        Hashmap *names; /* For name compression */
+        size_t opt_start, opt_size;
+
+        /* Parsed data */
+        DnsQuestion *question;
+        DnsAnswer *answer;
+        DnsResourceRecord *opt;
+
+        /* Packet reception metadata */
+        int ifindex;
+        int family, ipproto;
+        union in_addr_union sender, destination;
+        uint16_t sender_port, destination_port;
+        uint32_t ttl;
+
+        /* For support of truncated packets */
+        DnsPacket *more;
+
+        bool on_stack:1;
+        bool extracted:1;
+        bool refuse_compression:1;
+        bool canonical_form:1;
+};
+
+static inline uint8_t* DNS_PACKET_DATA(DnsPacket *p) {
+        if (_unlikely_(!p))
+                return NULL;
+
+        if (p->_data)
+                return p->_data;
+
+        return ((uint8_t*) p) + ALIGN(sizeof(DnsPacket));
+}
+
+#define DNS_PACKET_HEADER(p) ((DnsPacketHeader*) DNS_PACKET_DATA(p))
+#define DNS_PACKET_ID(p) DNS_PACKET_HEADER(p)->id
+#define DNS_PACKET_QR(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 15) & 1)
+#define DNS_PACKET_OPCODE(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 11) & 15)
+#define DNS_PACKET_AA(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 10) & 1)
+#define DNS_PACKET_TC(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 9) & 1)
+#define DNS_PACKET_RD(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 8) & 1)
+#define DNS_PACKET_RA(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 7) & 1)
+#define DNS_PACKET_AD(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 5) & 1)
+#define DNS_PACKET_CD(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 4) & 1)
+
+#define DNS_PACKET_FLAG_TC (UINT16_C(1) << 9)
+
+static inline uint16_t DNS_PACKET_RCODE(DnsPacket *p) {
+        uint16_t rcode;
+
+        if (p->opt)
+                rcode = (uint16_t) (p->opt->ttl >> 24);
+        else
+                rcode = 0;
+
+        return rcode | (be16toh(DNS_PACKET_HEADER(p)->flags) & 0xF);
+}
+
+static inline uint16_t DNS_PACKET_PAYLOAD_SIZE_MAX(DnsPacket *p) {
+
+        /* Returns the advertised maximum datagram size for replies, or the DNS default if there's nothing defined. */
+
+        if (p->opt)
+                return MAX(DNS_PACKET_UNICAST_SIZE_MAX, p->opt->key->class);
+
+        return DNS_PACKET_UNICAST_SIZE_MAX;
+}
+
+static inline bool DNS_PACKET_DO(DnsPacket *p) {
+        if (!p->opt)
+                return false;
+
+        return !!(p->opt->ttl & (1U << 15));
+}
+
+static inline bool DNS_PACKET_VERSION_SUPPORTED(DnsPacket *p) {
+        /* Returns true if this packet is in a version we support. Which means either non-EDNS or EDNS(0), but not EDNS
+         * of any newer versions */
+
+        if (!p->opt)
+                return true;
+
+        return DNS_RESOURCE_RECORD_OPT_VERSION_SUPPORTED(p->opt);
+}
+
+/* LLMNR defines some bits differently */
+#define DNS_PACKET_LLMNR_C(p) DNS_PACKET_AA(p)
+#define DNS_PACKET_LLMNR_T(p) DNS_PACKET_RD(p)
+
+#define DNS_PACKET_QDCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->qdcount)
+#define DNS_PACKET_ANCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->ancount)
+#define DNS_PACKET_NSCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->nscount)
+#define DNS_PACKET_ARCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->arcount)
+
+#define DNS_PACKET_MAKE_FLAGS(qr, opcode, aa, tc, rd, ra, ad, cd, rcode) \
+        (((uint16_t) !!(qr) << 15) |                                    \
+         ((uint16_t) ((opcode) & 15) << 11) |                           \
+         ((uint16_t) !!(aa) << 10) |                /* on LLMNR: c */   \
+         ((uint16_t) !!(tc) << 9) |                                     \
+         ((uint16_t) !!(rd) << 8) |                 /* on LLMNR: t */   \
+         ((uint16_t) !!(ra) << 7) |                                     \
+         ((uint16_t) !!(ad) << 5) |                                     \
+         ((uint16_t) !!(cd) << 4) |                                     \
+         ((uint16_t) ((rcode) & 15)))
+
+static inline unsigned DNS_PACKET_RRCOUNT(DnsPacket *p) {
+        return
+                (unsigned) DNS_PACKET_ANCOUNT(p) +
+                (unsigned) DNS_PACKET_NSCOUNT(p) +
+                (unsigned) DNS_PACKET_ARCOUNT(p);
+}
+
+int dns_packet_new(DnsPacket **p, DnsProtocol protocol, size_t mtu);
+int dns_packet_new_query(DnsPacket **p, DnsProtocol protocol, size_t mtu, bool dnssec_checking_disabled);
+
+void dns_packet_set_flags(DnsPacket *p, bool dnssec_checking_disabled, bool truncated);
+
+DnsPacket *dns_packet_ref(DnsPacket *p);
+DnsPacket *dns_packet_unref(DnsPacket *p);
+
+DEFINE_TRIVIAL_CLEANUP_FUNC(DnsPacket*, dns_packet_unref);
+
+int dns_packet_validate(DnsPacket *p);
+int dns_packet_validate_reply(DnsPacket *p);
+int dns_packet_validate_query(DnsPacket *p);
+
+int dns_packet_is_reply_for(DnsPacket *p, const DnsResourceKey *key);
+
+int dns_packet_append_blob(DnsPacket *p, const void *d, size_t sz, size_t *start);
+int dns_packet_append_uint8(DnsPacket *p, uint8_t v, size_t *start);
+int dns_packet_append_uint16(DnsPacket *p, uint16_t v, size_t *start);
+int dns_packet_append_uint32(DnsPacket *p, uint32_t v, size_t *start);
+int dns_packet_append_string(DnsPacket *p, const char *s, size_t *start);
+int dns_packet_append_raw_string(DnsPacket *p, const void *s, size_t size, size_t *start);
+int dns_packet_append_label(DnsPacket *p, const char *s, size_t l, bool canonical_candidate, size_t *start);
+int dns_packet_append_name(DnsPacket *p, const char *name, bool allow_compression, bool canonical_candidate, size_t *start);
+int dns_packet_append_key(DnsPacket *p, const DnsResourceKey *key, size_t *start);
+int dns_packet_append_rr(DnsPacket *p, const DnsResourceRecord *rr, size_t *start, size_t *rdata_start);
+int dns_packet_append_opt(DnsPacket *p, uint16_t max_udp_size, bool edns0_do, int rcode, size_t *start);
+int dns_packet_append_question(DnsPacket *p, DnsQuestion *q);
+int dns_packet_append_answer(DnsPacket *p, DnsAnswer *a);
+
+void dns_packet_truncate(DnsPacket *p, size_t sz);
+int dns_packet_truncate_opt(DnsPacket *p);
+
+int dns_packet_read(DnsPacket *p, size_t sz, const void **ret, size_t *start);
+int dns_packet_read_blob(DnsPacket *p, void *d, size_t sz, size_t *start);
+int dns_packet_read_uint8(DnsPacket *p, uint8_t *ret, size_t *start);
+int dns_packet_read_uint16(DnsPacket *p, uint16_t *ret, size_t *start);
+int dns_packet_read_uint32(DnsPacket *p, uint32_t *ret, size_t *start);
+int dns_packet_read_string(DnsPacket *p, char **ret, size_t *start);
+int dns_packet_read_raw_string(DnsPacket *p, const void **ret, size_t *size, size_t *start);
+int dns_packet_read_name(DnsPacket *p, char **ret, bool allow_compression, size_t *start);
+int dns_packet_read_key(DnsPacket *p, DnsResourceKey **ret, bool *ret_cache_flush, size_t *start);
+int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, bool *ret_cache_flush, size_t *start);
+
+void dns_packet_rewind(DnsPacket *p, size_t idx);
+
+int dns_packet_skip_question(DnsPacket *p);
+int dns_packet_extract(DnsPacket *p);
+
+static inline bool DNS_PACKET_SHALL_CACHE(DnsPacket *p) {
+        /* Never cache data originating from localhost, under the
+         * assumption, that it's coming from a locally DNS forwarder
+         * or server, that is caching on its own. */
+
+        return in_addr_is_localhost(p->family, &p->sender) == 0;
+}
+
+/* https://www.iana.org/assignments/dns-parameters/dns-parameters.xhtml#dns-parameters-6 */
+enum {
+        DNS_RCODE_SUCCESS = 0,
+        DNS_RCODE_FORMERR = 1,
+        DNS_RCODE_SERVFAIL = 2,
+        DNS_RCODE_NXDOMAIN = 3,
+        DNS_RCODE_NOTIMP = 4,
+        DNS_RCODE_REFUSED = 5,
+        DNS_RCODE_YXDOMAIN = 6,
+        DNS_RCODE_YXRRSET = 7,
+        DNS_RCODE_NXRRSET = 8,
+        DNS_RCODE_NOTAUTH = 9,
+        DNS_RCODE_NOTZONE = 10,
+        DNS_RCODE_BADVERS = 16,
+        DNS_RCODE_BADSIG = 16, /* duplicate value! */
+        DNS_RCODE_BADKEY = 17,
+        DNS_RCODE_BADTIME = 18,
+        DNS_RCODE_BADMODE = 19,
+        DNS_RCODE_BADNAME = 20,
+        DNS_RCODE_BADALG = 21,
+        DNS_RCODE_BADTRUNC = 22,
+        _DNS_RCODE_MAX_DEFINED,
+        _DNS_RCODE_MAX = 4095 /* 4 bit rcode in the header plus 8 bit rcode in OPT, makes 12 bit */
+};
+
+const char* dns_rcode_to_string(int i) _const_;
+int dns_rcode_from_string(const char *s) _pure_;
+
+const char* dns_protocol_to_string(DnsProtocol p) _const_;
+DnsProtocol dns_protocol_from_string(const char *s) _pure_;
+
+#define LLMNR_MULTICAST_IPV4_ADDRESS ((struct in_addr) { .s_addr = htobe32(224U << 24 | 252U) })
+#define LLMNR_MULTICAST_IPV6_ADDRESS ((struct in6_addr) { .s6_addr = { 0xFF, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x03 } })
+
+#define MDNS_MULTICAST_IPV4_ADDRESS  ((struct in_addr) { .s_addr = htobe32(224U << 24 | 251U) })
+#define MDNS_MULTICAST_IPV6_ADDRESS  ((struct in6_addr) { .s6_addr = { 0xFF, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xfb } })
+
+static inline uint64_t SD_RESOLVED_FLAGS_MAKE(DnsProtocol protocol, int family, bool authenticated) {
+        uint64_t f;
+
+        /* Converts a protocol + family into a flags field as used in queries and responses */
+
+        f = authenticated ? SD_RESOLVED_AUTHENTICATED : 0;
+
+        switch (protocol) {
+        case DNS_PROTOCOL_DNS:
+                return f|SD_RESOLVED_DNS;
+
+        case DNS_PROTOCOL_LLMNR:
+                return f|(family == AF_INET6 ? SD_RESOLVED_LLMNR_IPV6 : SD_RESOLVED_LLMNR_IPV4);
+
+        case DNS_PROTOCOL_MDNS:
+                return f|(family == AF_INET6 ? SD_RESOLVED_MDNS_IPV6 : SD_RESOLVED_MDNS_IPV4);
+
+        default:
+                return f;
+        }
+}
diff --git a/src/grp-resolve/libbasic-dns/include/basic-dns/resolved-dns-question.h b/src/grp-resolve/libbasic-dns/include/basic-dns/resolved-dns-question.h
new file mode 100644
index 0000000000..fb1b2d2410
--- /dev/null
+++ b/src/grp-resolve/libbasic-dns/include/basic-dns/resolved-dns-question.h
@@ -0,0 +1,74 @@
+#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/macro.h"
+
+typedef struct DnsQuestion DnsQuestion;
+
+#include "resolved-dns-rr.h"
+
+/* A simple array of resource keys */
+
+struct DnsQuestion {
+        unsigned n_ref;
+        unsigned n_keys, n_allocated;
+        DnsResourceKey* keys[0];
+};
+
+DnsQuestion *dns_question_new(unsigned n);
+DnsQuestion *dns_question_ref(DnsQuestion *q);
+DnsQuestion *dns_question_unref(DnsQuestion *q);
+
+int dns_question_new_address(DnsQuestion **ret, int family, const char *name, bool convert_idna);
+int dns_question_new_reverse(DnsQuestion **ret, int family, const union in_addr_union *a);
+int dns_question_new_service(DnsQuestion **ret, const char *service, const char *type, const char *domain, bool with_txt, bool convert_idna);
+
+int dns_question_add(DnsQuestion *q, DnsResourceKey *key);
+
+int dns_question_matches_rr(DnsQuestion *q, DnsResourceRecord *rr, const char *search_domain);
+int dns_question_matches_cname_or_dname(DnsQuestion *q, DnsResourceRecord *rr, const char* search_domain);
+int dns_question_is_valid_for_query(DnsQuestion *q);
+int dns_question_contains(DnsQuestion *a, const DnsResourceKey *k);
+int dns_question_is_equal(DnsQuestion *a, DnsQuestion *b);
+
+int dns_question_cname_redirect(DnsQuestion *q, const DnsResourceRecord *cname, DnsQuestion **ret);
+
+const char *dns_question_first_name(DnsQuestion *q);
+
+static inline unsigned dns_question_size(DnsQuestion *q) {
+        return q ? q->n_keys : 0;
+}
+
+static inline bool dns_question_isempty(DnsQuestion *q) {
+        return dns_question_size(q) <= 0;
+}
+
+DEFINE_TRIVIAL_CLEANUP_FUNC(DnsQuestion*, dns_question_unref);
+
+#define _DNS_QUESTION_FOREACH(u, key, q)                                \
+        for (unsigned UNIQ_T(i, u) = ({                                 \
+                                (key) = ((q) && (q)->n_keys > 0) ? (q)->keys[0] : NULL; \
+                                0;                                      \
+                        });                                             \
+             (q) && (UNIQ_T(i, u) < (q)->n_keys);                       \
+             UNIQ_T(i, u)++, (key) = (UNIQ_T(i, u) < (q)->n_keys ? (q)->keys[UNIQ_T(i, u)] : NULL))
+
+#define DNS_QUESTION_FOREACH(key, q) _DNS_QUESTION_FOREACH(UNIQ, key, q)
diff --git a/src/grp-resolve/libbasic-dns/include/basic-dns/resolved-dns-rr.h b/src/grp-resolve/libbasic-dns/include/basic-dns/resolved-dns-rr.h
new file mode 100644
index 0000000000..864c7c237f
--- /dev/null
+++ b/src/grp-resolve/libbasic-dns/include/basic-dns/resolved-dns-rr.h
@@ -0,0 +1,354 @@
+#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 <netinet/in.h>
+
+#include "systemd-basic/bitmap.h"
+#include "systemd-basic/hashmap.h"
+#include "systemd-basic/in-addr-util.h"
+#include "systemd-basic/list.h"
+#include "systemd-basic/string-util.h"
+
+#include "dns-type.h"
+
+typedef struct DnsResourceKey DnsResourceKey;
+typedef struct DnsResourceRecord DnsResourceRecord;
+typedef struct DnsTxtItem DnsTxtItem;
+
+/* DNSKEY RR flags */
+#define DNSKEY_FLAG_SEP      (UINT16_C(1) << 0)
+#define DNSKEY_FLAG_REVOKE   (UINT16_C(1) << 7)
+#define DNSKEY_FLAG_ZONE_KEY (UINT16_C(1) << 8)
+
+/* mDNS RR flags */
+#define MDNS_RR_CACHE_FLUSH  (UINT16_C(1) << 15)
+
+/* DNSSEC algorithm identifiers, see
+ * http://tools.ietf.org/html/rfc4034#appendix-A.1 and
+ * https://www.iana.org/assignments/dns-sec-alg-numbers/dns-sec-alg-numbers.xhtml */
+enum {
+        DNSSEC_ALGORITHM_RSAMD5 = 1,
+        DNSSEC_ALGORITHM_DH,
+        DNSSEC_ALGORITHM_DSA,
+        DNSSEC_ALGORITHM_ECC,
+        DNSSEC_ALGORITHM_RSASHA1,
+        DNSSEC_ALGORITHM_DSA_NSEC3_SHA1,
+        DNSSEC_ALGORITHM_RSASHA1_NSEC3_SHA1,
+        DNSSEC_ALGORITHM_RSASHA256 = 8,        /* RFC 5702 */
+        DNSSEC_ALGORITHM_RSASHA512 = 10,       /* RFC 5702 */
+        DNSSEC_ALGORITHM_ECC_GOST = 12,        /* RFC 5933 */
+        DNSSEC_ALGORITHM_ECDSAP256SHA256 = 13, /* RFC 6605 */
+        DNSSEC_ALGORITHM_ECDSAP384SHA384 = 14, /* RFC 6605 */
+        DNSSEC_ALGORITHM_INDIRECT = 252,
+        DNSSEC_ALGORITHM_PRIVATEDNS,
+        DNSSEC_ALGORITHM_PRIVATEOID,
+        _DNSSEC_ALGORITHM_MAX_DEFINED
+};
+
+/* DNSSEC digest identifiers, see
+ * https://www.iana.org/assignments/ds-rr-types/ds-rr-types.xhtml */
+enum {
+        DNSSEC_DIGEST_SHA1 = 1,
+        DNSSEC_DIGEST_SHA256 = 2,              /* RFC 4509 */
+        DNSSEC_DIGEST_GOST_R_34_11_94 = 3,     /* RFC 5933 */
+        DNSSEC_DIGEST_SHA384 = 4,              /* RFC 6605 */
+        _DNSSEC_DIGEST_MAX_DEFINED
+};
+
+/* DNSSEC NSEC3 hash algorithms, see
+ * https://www.iana.org/assignments/dnssec-nsec3-parameters/dnssec-nsec3-parameters.xhtml */
+enum {
+        NSEC3_ALGORITHM_SHA1 = 1,
+        _NSEC3_ALGORITHM_MAX_DEFINED
+};
+
+struct DnsResourceKey {
+        unsigned n_ref; /* (unsigned -1) for const keys, see below */
+        uint16_t class, type;
+        char *_name; /* don't access directly, use dns_resource_key_name()! */
+};
+
+/* Creates a temporary resource key. This is only useful to quickly
+ * look up something, without allocating a full DnsResourceKey object
+ * for it. Note that it is not OK to take references to this kind of
+ * resource key object. */
+#define DNS_RESOURCE_KEY_CONST(c, t, n)                 \
+        ((DnsResourceKey) {                             \
+                .n_ref = (unsigned) -1,                 \
+                .class = c,                             \
+                .type = t,                              \
+                ._name = (char*) n,                     \
+        })
+
+
+struct DnsTxtItem {
+        size_t length;
+        LIST_FIELDS(DnsTxtItem, items);
+        uint8_t data[];
+};
+
+struct DnsResourceRecord {
+        unsigned n_ref;
+        DnsResourceKey *key;
+
+        char *to_string;
+
+        uint32_t ttl;
+        usec_t expiry; /* RRSIG signature expiry */
+
+        /* How many labels to strip to determine "signer" of the RRSIG (aka, the zone). -1 if not signed. */
+        unsigned n_skip_labels_signer;
+        /* How many labels to strip to determine "synthesizing source" of this RR, i.e. the wildcard's immediate parent. -1 if not signed. */
+        unsigned n_skip_labels_source;
+
+        bool unparseable:1;
+
+        bool wire_format_canonical:1;
+        void *wire_format;
+        size_t wire_format_size;
+        size_t wire_format_rdata_offset;
+
+        union {
+                struct {
+                        void *data;
+                        size_t data_size;
+                } generic, opt;
+
+                struct {
+                        uint16_t priority;
+                        uint16_t weight;
+                        uint16_t port;
+                        char *name;
+                } srv;
+
+                struct {
+                        char *name;
+                } ptr, ns, cname, dname;
+
+                struct {
+                        char *cpu;
+                        char *os;
+                } hinfo;
+
+                struct {
+                        DnsTxtItem *items;
+                } txt, spf;
+
+                struct {
+                        struct in_addr in_addr;
+                } a;
+
+                struct {
+                        struct in6_addr in6_addr;
+                } aaaa;
+
+                struct {
+                        char *mname;
+                        char *rname;
+                        uint32_t serial;
+                        uint32_t refresh;
+                        uint32_t retry;
+                        uint32_t expire;
+                        uint32_t minimum;
+                } soa;
+
+                struct {
+                        uint16_t priority;
+                        char *exchange;
+                } mx;
+
+                /* https://tools.ietf.org/html/rfc1876 */
+                struct {
+                        uint8_t version;
+                        uint8_t size;
+                        uint8_t horiz_pre;
+                        uint8_t vert_pre;
+                        uint32_t latitude;
+                        uint32_t longitude;
+                        uint32_t altitude;
+                } loc;
+
+                /* https://tools.ietf.org/html/rfc4255#section-3.1 */
+                struct {
+                        uint8_t algorithm;
+                        uint8_t fptype;
+                        void *fingerprint;
+                        size_t fingerprint_size;
+                } sshfp;
+
+                /* http://tools.ietf.org/html/rfc4034#section-2.1 */
+                struct {
+                        uint16_t flags;
+                        uint8_t protocol;
+                        uint8_t algorithm;
+                        void* key;
+                        size_t key_size;
+                } dnskey;
+
+                /* http://tools.ietf.org/html/rfc4034#section-3.1 */
+                struct {
+                        uint16_t type_covered;
+                        uint8_t algorithm;
+                        uint8_t labels;
+                        uint32_t original_ttl;
+                        uint32_t expiration;
+                        uint32_t inception;
+                        uint16_t key_tag;
+                        char *signer;
+                        void *signature;
+                        size_t signature_size;
+                } rrsig;
+
+                /* https://tools.ietf.org/html/rfc4034#section-4.1 */
+                struct {
+                        char *next_domain_name;
+                        Bitmap *types;
+                } nsec;
+
+                /* https://tools.ietf.org/html/rfc4034#section-5.1 */
+                struct {
+                        uint16_t key_tag;
+                        uint8_t algorithm;
+                        uint8_t digest_type;
+                        void *digest;
+                        size_t digest_size;
+                } ds;
+
+                struct {
+                        uint8_t algorithm;
+                        uint8_t flags;
+                        uint16_t iterations;
+                        void *salt;
+                        size_t salt_size;
+                        void *next_hashed_name;
+                        size_t next_hashed_name_size;
+                        Bitmap *types;
+                } nsec3;
+
+                /* https://tools.ietf.org/html/draft-ietf-dane-protocol-23 */
+                struct {
+                        uint8_t cert_usage;
+                        uint8_t selector;
+                        uint8_t matching_type;
+                        void *data;
+                        size_t data_size;
+                } tlsa;
+
+                /* https://tools.ietf.org/html/rfc6844 */
+                struct {
+                        uint8_t flags;
+                        char *tag;
+                        void *value;
+                        size_t value_size;
+                } caa;
+        };
+};
+
+static inline const void* DNS_RESOURCE_RECORD_RDATA(DnsResourceRecord *rr) {
+        if (!rr)
+                return NULL;
+
+        if (!rr->wire_format)
+                return NULL;
+
+        assert(rr->wire_format_rdata_offset <= rr->wire_format_size);
+        return (uint8_t*) rr->wire_format + rr->wire_format_rdata_offset;
+}
+
+static inline size_t DNS_RESOURCE_RECORD_RDATA_SIZE(DnsResourceRecord *rr) {
+        if (!rr)
+                return 0;
+        if (!rr->wire_format)
+                return 0;
+
+        assert(rr->wire_format_rdata_offset <= rr->wire_format_size);
+        return rr->wire_format_size - rr->wire_format_rdata_offset;
+}
+
+static inline uint8_t DNS_RESOURCE_RECORD_OPT_VERSION_SUPPORTED(DnsResourceRecord *rr) {
+        assert(rr);
+        assert(rr->key->type == DNS_TYPE_OPT);
+
+        return ((rr->ttl >> 16) & 0xFF) == 0;
+}
+
+DnsResourceKey* dns_resource_key_new(uint16_t class, uint16_t type, const char *name);
+DnsResourceKey* dns_resource_key_new_redirect(const DnsResourceKey *key, const DnsResourceRecord *cname);
+int dns_resource_key_new_append_suffix(DnsResourceKey **ret, DnsResourceKey *key, char *name);
+DnsResourceKey* dns_resource_key_new_consume(uint16_t class, uint16_t type, char *name);
+DnsResourceKey* dns_resource_key_ref(DnsResourceKey *key);
+DnsResourceKey* dns_resource_key_unref(DnsResourceKey *key);
+const char* dns_resource_key_name(const DnsResourceKey *key);
+bool dns_resource_key_is_address(const DnsResourceKey *key);
+int dns_resource_key_equal(const DnsResourceKey *a, const DnsResourceKey *b);
+int dns_resource_key_match_rr(const DnsResourceKey *key, DnsResourceRecord *rr, const char *search_domain);
+int dns_resource_key_match_cname_or_dname(const DnsResourceKey *key, const DnsResourceKey *cname, const char *search_domain);
+int dns_resource_key_match_soa(const DnsResourceKey *key, const DnsResourceKey *soa);
+
+/* _DNS_{CLASS,TYPE}_STRING_MAX include one byte for NUL, which we use for space instead below.
+ * DNS_HOSTNAME_MAX does not include the NUL byte, so we need to add 1. */
+#define DNS_RESOURCE_KEY_STRING_MAX (_DNS_CLASS_STRING_MAX + _DNS_TYPE_STRING_MAX + DNS_HOSTNAME_MAX + 1)
+
+char* dns_resource_key_to_string(const DnsResourceKey *key, char *buf, size_t buf_size);
+ssize_t dns_resource_record_payload(DnsResourceRecord *rr, void **out);
+
+DEFINE_TRIVIAL_CLEANUP_FUNC(DnsResourceKey*, dns_resource_key_unref);
+
+static inline bool dns_key_is_shared(const DnsResourceKey *key) {
+        return IN_SET(key->type, DNS_TYPE_PTR);
+}
+
+bool dns_resource_key_reduce(DnsResourceKey **a, DnsResourceKey **b);
+
+DnsResourceRecord* dns_resource_record_new(DnsResourceKey *key);
+DnsResourceRecord* dns_resource_record_new_full(uint16_t class, uint16_t type, const char *name);
+DnsResourceRecord* dns_resource_record_ref(DnsResourceRecord *rr);
+DnsResourceRecord* dns_resource_record_unref(DnsResourceRecord *rr);
+int dns_resource_record_new_reverse(DnsResourceRecord **ret, int family, const union in_addr_union *address, const char *name);
+int dns_resource_record_new_address(DnsResourceRecord **ret, int family, const union in_addr_union *address, const char *name);
+int dns_resource_record_equal(const DnsResourceRecord *a, const DnsResourceRecord *b);
+const char* dns_resource_record_to_string(DnsResourceRecord *rr);
+DnsResourceRecord *dns_resource_record_copy(DnsResourceRecord *rr);
+DEFINE_TRIVIAL_CLEANUP_FUNC(DnsResourceRecord*, dns_resource_record_unref);
+
+int dns_resource_record_to_wire_format(DnsResourceRecord *rr, bool canonical);
+
+int dns_resource_record_signer(DnsResourceRecord *rr, const char **ret);
+int dns_resource_record_source(DnsResourceRecord *rr, const char **ret);
+int dns_resource_record_is_signer(DnsResourceRecord *rr, const char *zone);
+int dns_resource_record_is_synthetic(DnsResourceRecord *rr);
+
+int dns_resource_record_clamp_ttl(DnsResourceRecord **rr, uint32_t max_ttl);
+
+DnsTxtItem *dns_txt_item_free_all(DnsTxtItem *i);
+bool dns_txt_item_equal(DnsTxtItem *a, DnsTxtItem *b);
+DnsTxtItem *dns_txt_item_copy(DnsTxtItem *i);
+
+void dns_resource_record_hash_func(const void *i, struct siphash *state);
+
+extern const struct hash_ops dns_resource_key_hash_ops;
+extern const struct hash_ops dns_resource_record_hash_ops;
+
+int dnssec_algorithm_to_string_alloc(int i, char **ret);
+int dnssec_algorithm_from_string(const char *s) _pure_;
+
+int dnssec_digest_to_string_alloc(int i, char **ret);
+int dnssec_digest_from_string(const char *s) _pure_;
diff --git a/src/grp-resolve/libbasic-dns/src/dns-type.c b/src/grp-resolve/libbasic-dns/src/dns-type.c
new file mode 100644
index 0000000000..79603c4dfc
--- /dev/null
+++ b/src/grp-resolve/libbasic-dns/src/dns-type.c
@@ -0,0 +1,332 @@
+/***
+  This file is part of systemd.
+
+  Copyright 2014 Zbigniew Jędrzejewski-Szmek
+
+  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 <sys/socket.h>
+
+#include "basic-dns/dns-type.h"
+#include "systemd-basic/parse-util.h"
+#include "systemd-basic/string-util.h"
+
+typedef const struct {
+        uint16_t type;
+        const char *name;
+} dns_type;
+
+static const struct dns_type_name *
+lookup_dns_type (register const char *str, register unsigned int len);
+
+#include "dns_type-from-name.h"
+#include "dns_type-to-name.h"
+
+int dns_type_from_string(const char *s) {
+        const struct dns_type_name *sc;
+
+        assert(s);
+
+        sc = lookup_dns_type(s, strlen(s));
+        if (sc)
+                return sc->id;
+
+        s = startswith_no_case(s, "TYPE");
+        if (s) {
+                unsigned x;
+
+                if (safe_atou(s, &x) >= 0 &&
+                    x <= UINT16_MAX)
+                        return (int) x;
+        }
+
+        return _DNS_TYPE_INVALID;
+}
+
+bool dns_type_is_pseudo(uint16_t type) {
+
+        /* Checks whether the specified type is a "pseudo-type". What
+         * a "pseudo-type" precisely is, is defined only very weakly,
+         * but apparently entails all RR types that are not actually
+         * stored as RRs on the server and should hence also not be
+         * cached. We use this list primarily to validate NSEC type
+         * bitfields, and to verify what to cache. */
+
+        return IN_SET(type,
+                      0, /* A Pseudo RR type, according to RFC 2931 */
+                      DNS_TYPE_ANY,
+                      DNS_TYPE_AXFR,
+                      DNS_TYPE_IXFR,
+                      DNS_TYPE_OPT,
+                      DNS_TYPE_TSIG,
+                      DNS_TYPE_TKEY
+        );
+}
+
+bool dns_class_is_pseudo(uint16_t class) {
+        return class == DNS_TYPE_ANY;
+}
+
+bool dns_type_is_valid_query(uint16_t type) {
+
+        /* The types valid as questions in packets */
+
+        return !IN_SET(type,
+                       0,
+                       DNS_TYPE_OPT,
+                       DNS_TYPE_TSIG,
+                       DNS_TYPE_TKEY,
+
+                       /* RRSIG are technically valid as questions, but we refuse doing explicit queries for them, as
+                        * they aren't really payload, but signatures for payload, and cannot be validated on their
+                        * own. After all they are the signatures, and have no signatures of their own validating
+                        * them. */
+                       DNS_TYPE_RRSIG);
+}
+
+bool dns_type_is_zone_transer(uint16_t type) {
+
+        /* Zone transfers, either normal or incremental */
+
+        return IN_SET(type,
+                      DNS_TYPE_AXFR,
+                      DNS_TYPE_IXFR);
+}
+
+bool dns_type_is_valid_rr(uint16_t type) {
+
+        /* The types valid as RR in packets (but not necessarily
+         * stored on servers). */
+
+        return !IN_SET(type,
+                       DNS_TYPE_ANY,
+                       DNS_TYPE_AXFR,
+                       DNS_TYPE_IXFR);
+}
+
+bool dns_class_is_valid_rr(uint16_t class) {
+        return class != DNS_CLASS_ANY;
+}
+
+bool dns_type_may_redirect(uint16_t type) {
+        /* The following record types should never be redirected using
+         * CNAME/DNAME RRs. See
+         * <https://tools.ietf.org/html/rfc4035#section-2.5>. */
+
+        if (dns_type_is_pseudo(type))
+                return false;
+
+        return !IN_SET(type,
+                       DNS_TYPE_CNAME,
+                       DNS_TYPE_DNAME,
+                       DNS_TYPE_NSEC3,
+                       DNS_TYPE_NSEC,
+                       DNS_TYPE_RRSIG,
+                       DNS_TYPE_NXT,
+                       DNS_TYPE_SIG,
+                       DNS_TYPE_KEY);
+}
+
+bool dns_type_may_wildcard(uint16_t type) {
+
+        /* The following records may not be expanded from wildcard RRsets */
+
+        if (dns_type_is_pseudo(type))
+                return false;
+
+        return !IN_SET(type,
+                       DNS_TYPE_NSEC3,
+                       DNS_TYPE_SOA,
+
+                       /* Prohibited by https://tools.ietf.org/html/rfc4592#section-4.4 */
+                       DNS_TYPE_DNAME);
+}
+
+bool dns_type_apex_only(uint16_t type) {
+
+        /* Returns true for all RR types that may only appear signed in a zone apex */
+
+        return IN_SET(type,
+                      DNS_TYPE_SOA,
+                      DNS_TYPE_NS,            /* this one can appear elsewhere, too, but not signed */
+                      DNS_TYPE_DNSKEY,
+                      DNS_TYPE_NSEC3PARAM);
+}
+
+bool dns_type_is_dnssec(uint16_t type) {
+        return IN_SET(type,
+                      DNS_TYPE_DS,
+                      DNS_TYPE_DNSKEY,
+                      DNS_TYPE_RRSIG,
+                      DNS_TYPE_NSEC,
+                      DNS_TYPE_NSEC3,
+                      DNS_TYPE_NSEC3PARAM);
+}
+
+bool dns_type_is_obsolete(uint16_t type) {
+        return IN_SET(type,
+                      /* Obsoleted by RFC 973 */
+                      DNS_TYPE_MD,
+                      DNS_TYPE_MF,
+                      DNS_TYPE_MAILA,
+
+                      /* Kinda obsoleted by RFC 2505 */
+                      DNS_TYPE_MB,
+                      DNS_TYPE_MG,
+                      DNS_TYPE_MR,
+                      DNS_TYPE_MINFO,
+                      DNS_TYPE_MAILB,
+
+                      /* RFC1127 kinda obsoleted this by recommending against its use */
+                      DNS_TYPE_WKS,
+
+                      /* Declared historical by RFC 6563 */
+                      DNS_TYPE_A6,
+
+                      /* Obsoleted by DNSSEC-bis */
+                      DNS_TYPE_NXT,
+
+                      /* RFC 1035 removed support for concepts that needed this from RFC 883 */
+                      DNS_TYPE_NULL);
+}
+
+bool dns_type_needs_authentication(uint16_t type) {
+
+        /* Returns true for all (non-obsolete) RR types where records are not useful if they aren't
+         * authenticated. I.e. everything that contains crypto keys. */
+
+        return IN_SET(type,
+                      DNS_TYPE_CERT,
+                      DNS_TYPE_SSHFP,
+                      DNS_TYPE_IPSECKEY,
+                      DNS_TYPE_DS,
+                      DNS_TYPE_DNSKEY,
+                      DNS_TYPE_TLSA,
+                      DNS_TYPE_CDNSKEY,
+                      DNS_TYPE_OPENPGPKEY,
+                      DNS_TYPE_CAA);
+}
+
+int dns_type_to_af(uint16_t t) {
+        switch (t) {
+
+        case DNS_TYPE_A:
+                return AF_INET;
+
+        case DNS_TYPE_AAAA:
+                return AF_INET6;
+
+        case DNS_TYPE_ANY:
+                return AF_UNSPEC;
+
+        default:
+                return -EINVAL;
+        }
+}
+
+const char *dns_class_to_string(uint16_t class) {
+
+        switch (class) {
+
+        case DNS_CLASS_IN:
+                return "IN";
+
+        case DNS_CLASS_ANY:
+                return "ANY";
+        }
+
+        return NULL;
+}
+
+int dns_class_from_string(const char *s) {
+
+        if (!s)
+                return _DNS_CLASS_INVALID;
+
+        if (strcaseeq(s, "IN"))
+                return DNS_CLASS_IN;
+        else if (strcaseeq(s, "ANY"))
+                return DNS_CLASS_ANY;
+
+        return _DNS_CLASS_INVALID;
+}
+
+const char* tlsa_cert_usage_to_string(uint8_t cert_usage) {
+
+        switch (cert_usage) {
+
+        case 0:
+                return "CA constraint";
+
+        case 1:
+                return "Service certificate constraint";
+
+        case 2:
+                return "Trust anchor assertion";
+
+        case 3:
+                return "Domain-issued certificate";
+
+        case 4 ... 254:
+                return "Unassigned";
+
+        case 255:
+                return "Private use";
+        }
+
+        return NULL;  /* clang cannot count that we covered everything */
+}
+
+const char* tlsa_selector_to_string(uint8_t selector) {
+        switch (selector) {
+
+        case 0:
+                return "Full Certificate";
+
+        case 1:
+                return "SubjectPublicKeyInfo";
+
+        case 2 ... 254:
+                return "Unassigned";
+
+        case 255:
+                return "Private use";
+        }
+
+        return NULL;
+}
+
+const char* tlsa_matching_type_to_string(uint8_t selector) {
+
+        switch (selector) {
+
+        case 0:
+                return "No hash used";
+
+        case 1:
+                return "SHA-256";
+
+        case 2:
+                return "SHA-512";
+
+        case 3 ... 254:
+                return "Unassigned";
+
+        case 255:
+                return "Private use";
+        }
+
+        return NULL;
+}
diff --git a/src/grp-resolve/libbasic-dns/src/resolved-dns-answer.c b/src/grp-resolve/libbasic-dns/src/resolved-dns-answer.c
new file mode 100644
index 0000000000..afb0d3cafa
--- /dev/null
+++ b/src/grp-resolve/libbasic-dns/src/resolved-dns-answer.c
@@ -0,0 +1,858 @@
+/***
+  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-answer.h"
+#include "basic-dns/resolved-dns-dnssec.h"
+#include "systemd-basic/alloc-util.h"
+#include "systemd-basic/string-util.h"
+#include "systemd-shared/dns-domain.h"
+
+DnsAnswer *dns_answer_new(unsigned n) {
+        DnsAnswer *a;
+
+        a = malloc0(offsetof(DnsAnswer, items) + sizeof(DnsAnswerItem) * n);
+        if (!a)
+                return NULL;
+
+        a->n_ref = 1;
+        a->n_allocated = n;
+
+        return a;
+}
+
+DnsAnswer *dns_answer_ref(DnsAnswer *a) {
+        if (!a)
+                return NULL;
+
+        assert(a->n_ref > 0);
+        a->n_ref++;
+        return a;
+}
+
+static void dns_answer_flush(DnsAnswer *a) {
+        DnsResourceRecord *rr;
+
+        if (!a)
+                return;
+
+        DNS_ANSWER_FOREACH(rr, a)
+                dns_resource_record_unref(rr);
+
+        a->n_rrs = 0;
+}
+
+DnsAnswer *dns_answer_unref(DnsAnswer *a) {
+        if (!a)
+                return NULL;
+
+        assert(a->n_ref > 0);
+
+        if (a->n_ref == 1) {
+                dns_answer_flush(a);
+                free(a);
+        } else
+                a->n_ref--;
+
+        return NULL;
+}
+
+static int dns_answer_add_raw(DnsAnswer *a, DnsResourceRecord *rr, int ifindex, DnsAnswerFlags flags) {
+        assert(rr);
+
+        if (!a)
+                return -ENOSPC;
+
+        if (a->n_rrs >= a->n_allocated)
+                return -ENOSPC;
+
+        a->items[a->n_rrs++] = (DnsAnswerItem) {
+                .rr = dns_resource_record_ref(rr),
+                .ifindex = ifindex,
+                .flags = flags,
+        };
+
+        return 1;
+}
+
+static int dns_answer_add_raw_all(DnsAnswer *a, DnsAnswer *source) {
+        DnsResourceRecord *rr;
+        DnsAnswerFlags flags;
+        int ifindex, r;
+
+        DNS_ANSWER_FOREACH_FULL(rr, ifindex, flags, source) {
+                r = dns_answer_add_raw(a, rr, ifindex, flags);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+int dns_answer_add(DnsAnswer *a, DnsResourceRecord *rr, int ifindex, DnsAnswerFlags flags) {
+        unsigned i;
+        int r;
+
+        assert(rr);
+
+        if (!a)
+                return -ENOSPC;
+        if (a->n_ref > 1)
+                return -EBUSY;
+
+        for (i = 0; i < a->n_rrs; i++) {
+                if (a->items[i].ifindex != ifindex)
+                        continue;
+
+                r = dns_resource_record_equal(a->items[i].rr, rr);
+                if (r < 0)
+                        return r;
+                if (r > 0) {
+                        /* Don't mix contradicting TTLs (see below) */
+                        if ((rr->ttl == 0) != (a->items[i].rr->ttl == 0))
+                                return -EINVAL;
+
+                        /* Entry already exists, keep the entry with
+                         * the higher RR. */
+                        if (rr->ttl > a->items[i].rr->ttl) {
+                                dns_resource_record_ref(rr);
+                                dns_resource_record_unref(a->items[i].rr);
+                                a->items[i].rr = rr;
+                        }
+
+                        a->items[i].flags |= flags;
+                        return 0;
+                }
+
+                r = dns_resource_key_equal(a->items[i].rr->key, rr->key);
+                if (r < 0)
+                        return r;
+                if (r > 0) {
+                        /* There's already an RR of the same RRset in
+                         * place! Let's see if the TTLs more or less
+                         * match. We don't really care if they match
+                         * precisely, but we do care whether one is 0
+                         * and the other is not. See RFC 2181, Section
+                         * 5.2.*/
+
+                        if ((rr->ttl == 0) != (a->items[i].rr->ttl == 0))
+                                return -EINVAL;
+                }
+        }
+
+        return dns_answer_add_raw(a, rr, ifindex, flags);
+}
+
+static int dns_answer_add_all(DnsAnswer *a, DnsAnswer *b) {
+        DnsResourceRecord *rr;
+        DnsAnswerFlags flags;
+        int ifindex, r;
+
+        DNS_ANSWER_FOREACH_FULL(rr, ifindex, flags, b) {
+                r = dns_answer_add(a, rr, ifindex, flags);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+int dns_answer_add_extend(DnsAnswer **a, DnsResourceRecord *rr, int ifindex, DnsAnswerFlags flags) {
+        int r;
+
+        assert(a);
+        assert(rr);
+
+        r = dns_answer_reserve_or_clone(a, 1);
+        if (r < 0)
+                return r;
+
+        return dns_answer_add(*a, rr, ifindex, flags);
+}
+
+int dns_answer_add_soa(DnsAnswer *a, const char *name, uint32_t ttl, int ifindex) {
+        _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *soa = NULL;
+
+        soa = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_SOA, name);
+        if (!soa)
+                return -ENOMEM;
+
+        soa->ttl = ttl;
+
+        soa->soa.mname = strdup(name);
+        if (!soa->soa.mname)
+                return -ENOMEM;
+
+        soa->soa.rname = strappend("root.", name);
+        if (!soa->soa.rname)
+                return -ENOMEM;
+
+        soa->soa.serial = 1;
+        soa->soa.refresh = 1;
+        soa->soa.retry = 1;
+        soa->soa.expire = 1;
+        soa->soa.minimum = ttl;
+
+        return dns_answer_add(a, soa, ifindex, DNS_ANSWER_AUTHENTICATED);
+}
+
+int dns_answer_match_key(DnsAnswer *a, const DnsResourceKey *key, DnsAnswerFlags *ret_flags) {
+        DnsAnswerFlags flags = 0, i_flags;
+        DnsResourceRecord *i;
+        bool found = false;
+        int r;
+
+        assert(key);
+
+        DNS_ANSWER_FOREACH_FLAGS(i, i_flags, a) {
+                r = dns_resource_key_match_rr(key, i, NULL);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        continue;
+
+                if (!ret_flags)
+                        return 1;
+
+                if (found)
+                        flags &= i_flags;
+                else {
+                        flags = i_flags;
+                        found = true;
+                }
+        }
+
+        if (ret_flags)
+                *ret_flags = flags;
+
+        return found;
+}
+
+int dns_answer_contains_rr(DnsAnswer *a, DnsResourceRecord *rr, DnsAnswerFlags *ret_flags) {
+        DnsAnswerFlags flags = 0, i_flags;
+        DnsResourceRecord *i;
+        bool found = false;
+        int r;
+
+        assert(rr);
+
+        DNS_ANSWER_FOREACH_FLAGS(i, i_flags, a) {
+                r = dns_resource_record_equal(i, rr);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        continue;
+
+                if (!ret_flags)
+                        return 1;
+
+                if (found)
+                        flags &= i_flags;
+                else {
+                        flags = i_flags;
+                        found = true;
+                }
+        }
+
+        if (ret_flags)
+                *ret_flags = flags;
+
+        return found;
+}
+
+int dns_answer_contains_key(DnsAnswer *a, const DnsResourceKey *key, DnsAnswerFlags *ret_flags) {
+        DnsAnswerFlags flags = 0, i_flags;
+        DnsResourceRecord *i;
+        bool found = false;
+        int r;
+
+        assert(key);
+
+        DNS_ANSWER_FOREACH_FLAGS(i, i_flags, a) {
+                r = dns_resource_key_equal(i->key, key);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        continue;
+
+                if (!ret_flags)
+                        return true;
+
+                if (found)
+                        flags &= i_flags;
+                else {
+                        flags = i_flags;
+                        found = true;
+                }
+        }
+
+        if (ret_flags)
+                *ret_flags = flags;
+
+        return found;
+}
+
+int dns_answer_contains_nsec_or_nsec3(DnsAnswer *a) {
+        DnsResourceRecord *i;
+
+        DNS_ANSWER_FOREACH(i, a) {
+                if (IN_SET(i->key->type, DNS_TYPE_NSEC, DNS_TYPE_NSEC3))
+                        return true;
+        }
+
+        return false;
+}
+
+int dns_answer_contains_zone_nsec3(DnsAnswer *answer, const char *zone) {
+        DnsResourceRecord *rr;
+        int r;
+
+        /* Checks whether the specified answer contains at least one NSEC3 RR in the specified zone */
+
+        DNS_ANSWER_FOREACH(rr, answer) {
+                const char *p;
+
+                if (rr->key->type != DNS_TYPE_NSEC3)
+                        continue;
+
+                p = dns_resource_key_name(rr->key);
+                r = dns_name_parent(&p);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        continue;
+
+                r = dns_name_equal(p, zone);
+                if (r != 0)
+                        return r;
+        }
+
+        return false;
+}
+
+int dns_answer_find_soa(DnsAnswer *a, const DnsResourceKey *key, DnsResourceRecord **ret, DnsAnswerFlags *flags) {
+        DnsResourceRecord *rr, *soa = NULL;
+        DnsAnswerFlags rr_flags, soa_flags = 0;
+        int r;
+
+        assert(key);
+
+        /* For a SOA record we can never find a matching SOA record */
+        if (key->type == DNS_TYPE_SOA)
+                return 0;
+
+        DNS_ANSWER_FOREACH_FLAGS(rr, rr_flags, a) {
+                r = dns_resource_key_match_soa(key, rr->key);
+                if (r < 0)
+                        return r;
+                if (r > 0) {
+
+                        if (soa) {
+                                r = dns_name_endswith(dns_resource_key_name(rr->key), dns_resource_key_name(soa->key));
+                                if (r < 0)
+                                        return r;
+                                if (r > 0)
+                                        continue;
+                        }
+
+                        soa = rr;
+                        soa_flags = rr_flags;
+                }
+        }
+
+        if (!soa)
+                return 0;
+
+        if (ret)
+                *ret = soa;
+        if (flags)
+                *flags = soa_flags;
+
+        return 1;
+}
+
+int dns_answer_find_cname_or_dname(DnsAnswer *a, const DnsResourceKey *key, DnsResourceRecord **ret, DnsAnswerFlags *flags) {
+        DnsResourceRecord *rr;
+        DnsAnswerFlags rr_flags;
+        int r;
+
+        assert(key);
+
+        /* For a {C,D}NAME record we can never find a matching {C,D}NAME record */
+        if (!dns_type_may_redirect(key->type))
+                return 0;
+
+        DNS_ANSWER_FOREACH_FLAGS(rr, rr_flags, a) {
+                r = dns_resource_key_match_cname_or_dname(key, rr->key, NULL);
+                if (r < 0)
+                        return r;
+                if (r > 0) {
+                        if (ret)
+                                *ret = rr;
+                        if (flags)
+                                *flags = rr_flags;
+                        return 1;
+                }
+        }
+
+        return 0;
+}
+
+int dns_answer_merge(DnsAnswer *a, DnsAnswer *b, DnsAnswer **ret) {
+        _cleanup_(dns_answer_unrefp) DnsAnswer *k = NULL;
+        int r;
+
+        assert(ret);
+
+        if (dns_answer_size(a) <= 0) {
+                *ret = dns_answer_ref(b);
+                return 0;
+        }
+
+        if (dns_answer_size(b) <= 0) {
+                *ret = dns_answer_ref(a);
+                return 0;
+        }
+
+        k = dns_answer_new(a->n_rrs + b->n_rrs);
+        if (!k)
+                return -ENOMEM;
+
+        r = dns_answer_add_raw_all(k, a);
+        if (r < 0)
+                return r;
+
+        r = dns_answer_add_all(k, b);
+        if (r < 0)
+                return r;
+
+        *ret = k;
+        k = NULL;
+
+        return 0;
+}
+
+int dns_answer_extend(DnsAnswer **a, DnsAnswer *b) {
+        DnsAnswer *merged;
+        int r;
+
+        assert(a);
+
+        r = dns_answer_merge(*a, b, &merged);
+        if (r < 0)
+                return r;
+
+        dns_answer_unref(*a);
+        *a = merged;
+
+        return 0;
+}
+
+int dns_answer_remove_by_key(DnsAnswer **a, const DnsResourceKey *key) {
+        bool found = false, other = false;
+        DnsResourceRecord *rr;
+        unsigned i;
+        int r;
+
+        assert(a);
+        assert(key);
+
+        /* Remove all entries matching the specified key from *a */
+
+        DNS_ANSWER_FOREACH(rr, *a) {
+                r = dns_resource_key_equal(rr->key, key);
+                if (r < 0)
+                        return r;
+                if (r > 0)
+                        found = true;
+                else
+                        other = true;
+
+                if (found && other)
+                        break;
+        }
+
+        if (!found)
+                return 0;
+
+        if (!other) {
+                *a = dns_answer_unref(*a); /* Return NULL for the empty answer */
+                return 1;
+        }
+
+        if ((*a)->n_ref > 1) {
+                _cleanup_(dns_answer_unrefp) DnsAnswer *copy = NULL;
+                DnsAnswerFlags flags;
+                int ifindex;
+
+                copy = dns_answer_new((*a)->n_rrs);
+                if (!copy)
+                        return -ENOMEM;
+
+                DNS_ANSWER_FOREACH_FULL(rr, ifindex, flags, *a) {
+                        r = dns_resource_key_equal(rr->key, key);
+                        if (r < 0)
+                                return r;
+                        if (r > 0)
+                                continue;
+
+                        r = dns_answer_add_raw(copy, rr, ifindex, flags);
+                        if (r < 0)
+                                return r;
+                }
+
+                dns_answer_unref(*a);
+                *a = copy;
+                copy = NULL;
+
+                return 1;
+        }
+
+        /* Only a single reference, edit in-place */
+
+        i = 0;
+        for (;;) {
+                if (i >= (*a)->n_rrs)
+                        break;
+
+                r = dns_resource_key_equal((*a)->items[i].rr->key, key);
+                if (r < 0)
+                        return r;
+                if (r > 0) {
+                        /* Kill this entry */
+
+                        dns_resource_record_unref((*a)->items[i].rr);
+                        memmove((*a)->items + i, (*a)->items + i + 1, sizeof(DnsAnswerItem) * ((*a)->n_rrs - i - 1));
+                        (*a)->n_rrs--;
+                        continue;
+
+                } else
+                        /* Keep this entry */
+                        i++;
+        }
+
+        return 1;
+}
+
+int dns_answer_remove_by_rr(DnsAnswer **a, DnsResourceRecord *rm) {
+        bool found = false, other = false;
+        DnsResourceRecord *rr;
+        unsigned i;
+        int r;
+
+        assert(a);
+        assert(rm);
+
+        /* Remove all entries matching the specified RR from *a */
+
+        DNS_ANSWER_FOREACH(rr, *a) {
+                r = dns_resource_record_equal(rr, rm);
+                if (r < 0)
+                        return r;
+                if (r > 0)
+                        found = true;
+                else
+                        other = true;
+
+                if (found && other)
+                        break;
+        }
+
+        if (!found)
+                return 0;
+
+        if (!other) {
+                *a = dns_answer_unref(*a); /* Return NULL for the empty answer */
+                return 1;
+        }
+
+        if ((*a)->n_ref > 1) {
+                _cleanup_(dns_answer_unrefp) DnsAnswer *copy = NULL;
+                DnsAnswerFlags flags;
+                int ifindex;
+
+                copy = dns_answer_new((*a)->n_rrs);
+                if (!copy)
+                        return -ENOMEM;
+
+                DNS_ANSWER_FOREACH_FULL(rr, ifindex, flags, *a) {
+                        r = dns_resource_record_equal(rr, rm);
+                        if (r < 0)
+                                return r;
+                        if (r > 0)
+                                continue;
+
+                        r = dns_answer_add_raw(copy, rr, ifindex, flags);
+                        if (r < 0)
+                                return r;
+                }
+
+                dns_answer_unref(*a);
+                *a = copy;
+                copy = NULL;
+
+                return 1;
+        }
+
+        /* Only a single reference, edit in-place */
+
+        i = 0;
+        for (;;) {
+                if (i >= (*a)->n_rrs)
+                        break;
+
+                r = dns_resource_record_equal((*a)->items[i].rr, rm);
+                if (r < 0)
+                        return r;
+                if (r > 0) {
+                        /* Kill this entry */
+
+                        dns_resource_record_unref((*a)->items[i].rr);
+                        memmove((*a)->items + i, (*a)->items + i + 1, sizeof(DnsAnswerItem) * ((*a)->n_rrs - i - 1));
+                        (*a)->n_rrs--;
+                        continue;
+
+                } else
+                        /* Keep this entry */
+                        i++;
+        }
+
+        return 1;
+}
+
+int dns_answer_copy_by_key(DnsAnswer **a, DnsAnswer *source, const DnsResourceKey *key, DnsAnswerFlags or_flags) {
+        DnsResourceRecord *rr_source;
+        int ifindex_source, r;
+        DnsAnswerFlags flags_source;
+
+        assert(a);
+        assert(key);
+
+        /* Copy all RRs matching the specified key from source into *a */
+
+        DNS_ANSWER_FOREACH_FULL(rr_source, ifindex_source, flags_source, source) {
+
+                r = dns_resource_key_equal(rr_source->key, key);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        continue;
+
+                /* Make space for at least one entry */
+                r = dns_answer_reserve_or_clone(a, 1);
+                if (r < 0)
+                        return r;
+
+                r = dns_answer_add(*a, rr_source, ifindex_source, flags_source|or_flags);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+int dns_answer_move_by_key(DnsAnswer **to, DnsAnswer **from, const DnsResourceKey *key, DnsAnswerFlags or_flags) {
+        int r;
+
+        assert(to);
+        assert(from);
+        assert(key);
+
+        r = dns_answer_copy_by_key(to, *from, key, or_flags);
+        if (r < 0)
+                return r;
+
+        return dns_answer_remove_by_key(from, key);
+}
+
+void dns_answer_order_by_scope(DnsAnswer *a, bool prefer_link_local) {
+        DnsAnswerItem *items;
+        unsigned i, start, end;
+
+        if (!a)
+                return;
+
+        if (a->n_rrs <= 1)
+                return;
+
+        start = 0;
+        end = a->n_rrs-1;
+
+        /* RFC 4795, Section 2.6 suggests we should order entries
+         * depending on whether the sender is a link-local address. */
+
+        items = newa(DnsAnswerItem, a->n_rrs);
+        for (i = 0; i < a->n_rrs; i++) {
+
+                if (a->items[i].rr->key->class == DNS_CLASS_IN &&
+                    ((a->items[i].rr->key->type == DNS_TYPE_A && in_addr_is_link_local(AF_INET, (union in_addr_union*) &a->items[i].rr->a.in_addr) != prefer_link_local) ||
+                     (a->items[i].rr->key->type == DNS_TYPE_AAAA && in_addr_is_link_local(AF_INET6, (union in_addr_union*) &a->items[i].rr->aaaa.in6_addr) != prefer_link_local)))
+                        /* Order address records that are not preferred to the end of the array */
+                        items[end--] = a->items[i];
+                else
+                        /* Order all other records to the beginning of the array */
+                        items[start++] = a->items[i];
+        }
+
+        assert(start == end+1);
+        memcpy(a->items, items, sizeof(DnsAnswerItem) * a->n_rrs);
+}
+
+int dns_answer_reserve(DnsAnswer **a, unsigned n_free) {
+        DnsAnswer *n;
+
+        assert(a);
+
+        if (n_free <= 0)
+                return 0;
+
+        if (*a) {
+                unsigned ns;
+
+                if ((*a)->n_ref > 1)
+                        return -EBUSY;
+
+                ns = (*a)->n_rrs + n_free;
+
+                if ((*a)->n_allocated >= ns)
+                        return 0;
+
+                /* Allocate more than we need */
+                ns *= 2;
+
+                n = realloc(*a, offsetof(DnsAnswer, items) + sizeof(DnsAnswerItem) * ns);
+                if (!n)
+                        return -ENOMEM;
+
+                n->n_allocated = ns;
+        } else {
+                n = dns_answer_new(n_free);
+                if (!n)
+                        return -ENOMEM;
+        }
+
+        *a = n;
+        return 0;
+}
+
+int dns_answer_reserve_or_clone(DnsAnswer **a, unsigned n_free) {
+        _cleanup_(dns_answer_unrefp) DnsAnswer *n = NULL;
+        int r;
+
+        assert(a);
+
+        /* Tries to extend the DnsAnswer object. And if that's not
+         * possible, since we are not the sole owner, then allocate a
+         * new, appropriately sized one. Either way, after this call
+         * the object will only have a single reference, and has room
+         * for at least the specified number of RRs. */
+
+        r = dns_answer_reserve(a, n_free);
+        if (r != -EBUSY)
+                return r;
+
+        assert(*a);
+
+        n = dns_answer_new(((*a)->n_rrs + n_free) * 2);
+        if (!n)
+                return -ENOMEM;
+
+        r = dns_answer_add_raw_all(n, *a);
+        if (r < 0)
+                return r;
+
+        dns_answer_unref(*a);
+        *a = n;
+        n = NULL;
+
+        return 0;
+}
+
+void dns_answer_dump(DnsAnswer *answer, FILE *f) {
+        DnsResourceRecord *rr;
+        DnsAnswerFlags flags;
+        int ifindex;
+
+        if (!f)
+                f = stdout;
+
+        DNS_ANSWER_FOREACH_FULL(rr, ifindex, flags, answer) {
+                const char *t;
+
+                fputc('\t', f);
+
+                t = dns_resource_record_to_string(rr);
+                if (!t) {
+                        log_oom();
+                        continue;
+                }
+
+                fputs(t, f);
+
+                if (ifindex != 0 || flags & (DNS_ANSWER_AUTHENTICATED|DNS_ANSWER_CACHEABLE|DNS_ANSWER_SHARED_OWNER))
+                        fputs("\t;", f);
+
+                if (ifindex != 0)
+                        printf(" ifindex=%i", ifindex);
+                if (flags & DNS_ANSWER_AUTHENTICATED)
+                        fputs(" authenticated", f);
+                if (flags & DNS_ANSWER_CACHEABLE)
+                        fputs(" cachable", f);
+                if (flags & DNS_ANSWER_SHARED_OWNER)
+                        fputs(" shared-owner", f);
+
+                fputc('\n', f);
+        }
+}
+
+bool dns_answer_has_dname_for_cname(DnsAnswer *a, DnsResourceRecord *cname) {
+        DnsResourceRecord *rr;
+        int r;
+
+        assert(cname);
+
+        /* Checks whether the answer contains a DNAME record that indicates that the specified CNAME record is
+         * synthesized from it */
+
+        if (cname->key->type != DNS_TYPE_CNAME)
+                return 0;
+
+        DNS_ANSWER_FOREACH(rr, a) {
+                _cleanup_free_ char *n = NULL;
+
+                if (rr->key->type != DNS_TYPE_DNAME)
+                        continue;
+                if (rr->key->class != cname->key->class)
+                        continue;
+
+                r = dns_name_change_suffix(cname->cname.name, rr->dname.name, dns_resource_key_name(rr->key), &n);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        continue;
+
+                r = dns_name_equal(n, dns_resource_key_name(cname->key));
+                if (r < 0)
+                        return r;
+                if (r > 0)
+                        return 1;
+
+        }
+
+        return 0;
+}
diff --git a/src/grp-resolve/libbasic-dns/src/resolved-dns-dnssec.c b/src/grp-resolve/libbasic-dns/src/resolved-dns-dnssec.c
new file mode 100644
index 0000000000..26ee159d60
--- /dev/null
+++ b/src/grp-resolve/libbasic-dns/src/resolved-dns-dnssec.c
@@ -0,0 +1,2199 @@
+/***
+  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/>.
+***/
+
+#ifdef HAVE_GCRYPT
+#include <gcrypt.h>
+#endif
+
+#include "basic-dns/resolved-dns-dnssec.h"
+#include "basic-dns/resolved-dns-packet.h"
+#include "systemd-basic/alloc-util.h"
+#include "systemd-basic/hexdecoct.h"
+#include "systemd-basic/string-table.h"
+#include "systemd-shared/dns-domain.h"
+#include "systemd-shared/gcrypt-util.h"
+
+#define VERIFY_RRS_MAX 256
+#define MAX_KEY_SIZE (32*1024)
+
+/* Permit a maximum clock skew of 1h 10min. This should be enough to deal with DST confusion */
+#define SKEW_MAX (1*USEC_PER_HOUR + 10*USEC_PER_MINUTE)
+
+/* Maximum number of NSEC3 iterations we'll do. RFC5155 says 2500 shall be the maximum useful value */
+#define NSEC3_ITERATIONS_MAX 2500
+
+/*
+ * The DNSSEC Chain of trust:
+ *
+ *            Normal RRs are protected via RRSIG RRs in combination with DNSKEY RRs, all in the same zone
+ *            DNSKEY RRs are either protected like normal RRs, or via a DS from a zone "higher" up the tree
+ *            DS RRs are protected like normal RRs
+ *
+ * Example chain:
+ *            Normal RR → RRSIG/DNSKEY+ → DS → RRSIG/DNSKEY+ → DS → ... → DS → RRSIG/DNSKEY+ → DS
+ */
+
+uint16_t dnssec_keytag(DnsResourceRecord *dnskey, bool mask_revoke) {
+        const uint8_t *p;
+        uint32_t sum, f;
+        size_t i;
+
+        /* The algorithm from RFC 4034, Appendix B. */
+
+        assert(dnskey);
+        assert(dnskey->key->type == DNS_TYPE_DNSKEY);
+
+        f = (uint32_t) dnskey->dnskey.flags;
+
+        if (mask_revoke)
+                f &= ~DNSKEY_FLAG_REVOKE;
+
+        sum = f + ((((uint32_t) dnskey->dnskey.protocol) << 8) + (uint32_t) dnskey->dnskey.algorithm);
+
+        p = dnskey->dnskey.key;
+
+        for (i = 0; i < dnskey->dnskey.key_size; i++)
+                sum += (i & 1) == 0 ? (uint32_t) p[i] << 8 : (uint32_t) p[i];
+
+        sum += (sum >> 16) & UINT32_C(0xFFFF);
+
+        return sum & UINT32_C(0xFFFF);
+}
+
+int dnssec_canonicalize(const char *n, char *buffer, size_t buffer_max) {
+        size_t c = 0;
+        int r;
+
+        /* Converts the specified hostname into DNSSEC canonicalized
+         * form. */
+
+        if (buffer_max < 2)
+                return -ENOBUFS;
+
+        for (;;) {
+                r = dns_label_unescape(&n, buffer, buffer_max);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        break;
+
+                if (buffer_max < (size_t) r + 2)
+                        return -ENOBUFS;
+
+                /* The DNSSEC canonical form is not clear on what to
+                 * do with dots appearing in labels, the way DNS-SD
+                 * does it. Refuse it for now. */
+
+                if (memchr(buffer, '.', r))
+                        return -EINVAL;
+
+                ascii_strlower_n(buffer, (size_t) r);
+                buffer[r] = '.';
+
+                buffer += r + 1;
+                c += r + 1;
+
+                buffer_max -= r + 1;
+        }
+
+        if (c <= 0) {
+                /* Not even a single label: this is the root domain name */
+
+                assert(buffer_max > 2);
+                buffer[0] = '.';
+                buffer[1] = 0;
+
+                return 1;
+        }
+
+        return (int) c;
+}
+
+#ifdef HAVE_GCRYPT
+
+static int rr_compare(const void *a, const void *b) {
+        DnsResourceRecord **x = (DnsResourceRecord**) a, **y = (DnsResourceRecord**) b;
+        size_t m;
+        int r;
+
+        /* Let's order the RRs according to RFC 4034, Section 6.3 */
+
+        assert(x);
+        assert(*x);
+        assert((*x)->wire_format);
+        assert(y);
+        assert(*y);
+        assert((*y)->wire_format);
+
+        m = MIN(DNS_RESOURCE_RECORD_RDATA_SIZE(*x), DNS_RESOURCE_RECORD_RDATA_SIZE(*y));
+
+        r = memcmp(DNS_RESOURCE_RECORD_RDATA(*x), DNS_RESOURCE_RECORD_RDATA(*y), m);
+        if (r != 0)
+                return r;
+
+        if (DNS_RESOURCE_RECORD_RDATA_SIZE(*x) < DNS_RESOURCE_RECORD_RDATA_SIZE(*y))
+                return -1;
+        else if (DNS_RESOURCE_RECORD_RDATA_SIZE(*x) > DNS_RESOURCE_RECORD_RDATA_SIZE(*y))
+                return 1;
+
+        return 0;
+}
+
+static int dnssec_rsa_verify_raw(
+                const char *hash_algorithm,
+                const void *signature, size_t signature_size,
+                const void *data, size_t data_size,
+                const void *exponent, size_t exponent_size,
+                const void *modulus, size_t modulus_size) {
+
+        gcry_sexp_t public_key_sexp = NULL, data_sexp = NULL, signature_sexp = NULL;
+        gcry_mpi_t n = NULL, e = NULL, s = NULL;
+        gcry_error_t ge;
+        int r;
+
+        assert(hash_algorithm);
+
+        ge = gcry_mpi_scan(&s, GCRYMPI_FMT_USG, signature, signature_size, NULL);
+        if (ge != 0) {
+                r = -EIO;
+                goto finish;
+        }
+
+        ge = gcry_mpi_scan(&e, GCRYMPI_FMT_USG, exponent, exponent_size, NULL);
+        if (ge != 0) {
+                r = -EIO;
+                goto finish;
+        }
+
+        ge = gcry_mpi_scan(&n, GCRYMPI_FMT_USG, modulus, modulus_size, NULL);
+        if (ge != 0) {
+                r = -EIO;
+                goto finish;
+        }
+
+        ge = gcry_sexp_build(&signature_sexp,
+                             NULL,
+                             "(sig-val (rsa (s %m)))",
+                             s);
+
+        if (ge != 0) {
+                r = -EIO;
+                goto finish;
+        }
+
+        ge = gcry_sexp_build(&data_sexp,
+                             NULL,
+                             "(data (flags pkcs1) (hash %s %b))",
+                             hash_algorithm,
+                             (int) data_size,
+                             data);
+        if (ge != 0) {
+                r = -EIO;
+                goto finish;
+        }
+
+        ge = gcry_sexp_build(&public_key_sexp,
+                             NULL,
+                             "(public-key (rsa (n %m) (e %m)))",
+                             n,
+                             e);
+        if (ge != 0) {
+                r = -EIO;
+                goto finish;
+        }
+
+        ge = gcry_pk_verify(signature_sexp, data_sexp, public_key_sexp);
+        if (gpg_err_code(ge) == GPG_ERR_BAD_SIGNATURE)
+                r = 0;
+        else if (ge != 0) {
+                log_debug("RSA signature check failed: %s", gpg_strerror(ge));
+                r = -EIO;
+        } else
+                r = 1;
+
+finish:
+        if (e)
+                gcry_mpi_release(e);
+        if (n)
+                gcry_mpi_release(n);
+        if (s)
+                gcry_mpi_release(s);
+
+        if (public_key_sexp)
+                gcry_sexp_release(public_key_sexp);
+        if (signature_sexp)
+                gcry_sexp_release(signature_sexp);
+        if (data_sexp)
+                gcry_sexp_release(data_sexp);
+
+        return r;
+}
+
+static int dnssec_rsa_verify(
+                const char *hash_algorithm,
+                const void *hash, size_t hash_size,
+                DnsResourceRecord *rrsig,
+                DnsResourceRecord *dnskey) {
+
+        size_t exponent_size, modulus_size;
+        void *exponent, *modulus;
+
+        assert(hash_algorithm);
+        assert(hash);
+        assert(hash_size > 0);
+        assert(rrsig);
+        assert(dnskey);
+
+        if (*(uint8_t*) dnskey->dnskey.key == 0) {
+                /* exponent is > 255 bytes long */
+
+                exponent = (uint8_t*) dnskey->dnskey.key + 3;
+                exponent_size =
+                        ((size_t) (((uint8_t*) dnskey->dnskey.key)[1]) << 8) |
+                        ((size_t) ((uint8_t*) dnskey->dnskey.key)[2]);
+
+                if (exponent_size < 256)
+                        return -EINVAL;
+
+                if (3 + exponent_size >= dnskey->dnskey.key_size)
+                        return -EINVAL;
+
+                modulus = (uint8_t*) dnskey->dnskey.key + 3 + exponent_size;
+                modulus_size = dnskey->dnskey.key_size - 3 - exponent_size;
+
+        } else {
+                /* exponent is <= 255 bytes long */
+
+                exponent = (uint8_t*) dnskey->dnskey.key + 1;
+                exponent_size = (size_t) ((uint8_t*) dnskey->dnskey.key)[0];
+
+                if (exponent_size <= 0)
+                        return -EINVAL;
+
+                if (1 + exponent_size >= dnskey->dnskey.key_size)
+                        return -EINVAL;
+
+                modulus = (uint8_t*) dnskey->dnskey.key + 1 + exponent_size;
+                modulus_size = dnskey->dnskey.key_size - 1 - exponent_size;
+        }
+
+        return dnssec_rsa_verify_raw(
+                        hash_algorithm,
+                        rrsig->rrsig.signature, rrsig->rrsig.signature_size,
+                        hash, hash_size,
+                        exponent, exponent_size,
+                        modulus, modulus_size);
+}
+
+static int dnssec_ecdsa_verify_raw(
+                const char *hash_algorithm,
+                const char *curve,
+                const void *signature_r, size_t signature_r_size,
+                const void *signature_s, size_t signature_s_size,
+                const void *data, size_t data_size,
+                const void *key, size_t key_size) {
+
+        gcry_sexp_t public_key_sexp = NULL, data_sexp = NULL, signature_sexp = NULL;
+        gcry_mpi_t q = NULL, r = NULL, s = NULL;
+        gcry_error_t ge;
+        int k;
+
+        assert(hash_algorithm);
+
+        ge = gcry_mpi_scan(&r, GCRYMPI_FMT_USG, signature_r, signature_r_size, NULL);
+        if (ge != 0) {
+                k = -EIO;
+                goto finish;
+        }
+
+        ge = gcry_mpi_scan(&s, GCRYMPI_FMT_USG, signature_s, signature_s_size, NULL);
+        if (ge != 0) {
+                k = -EIO;
+                goto finish;
+        }
+
+        ge = gcry_mpi_scan(&q, GCRYMPI_FMT_USG, key, key_size, NULL);
+        if (ge != 0) {
+                k = -EIO;
+                goto finish;
+        }
+
+        ge = gcry_sexp_build(&signature_sexp,
+                             NULL,
+                             "(sig-val (ecdsa (r %m) (s %m)))",
+                             r,
+                             s);
+        if (ge != 0) {
+                k = -EIO;
+                goto finish;
+        }
+
+        ge = gcry_sexp_build(&data_sexp,
+                             NULL,
+                             "(data (flags rfc6979) (hash %s %b))",
+                             hash_algorithm,
+                             (int) data_size,
+                             data);
+        if (ge != 0) {
+                k = -EIO;
+                goto finish;
+        }
+
+        ge = gcry_sexp_build(&public_key_sexp,
+                             NULL,
+                             "(public-key (ecc (curve %s) (q %m)))",
+                             curve,
+                             q);
+        if (ge != 0) {
+                k = -EIO;
+                goto finish;
+        }
+
+        ge = gcry_pk_verify(signature_sexp, data_sexp, public_key_sexp);
+        if (gpg_err_code(ge) == GPG_ERR_BAD_SIGNATURE)
+                k = 0;
+        else if (ge != 0) {
+                log_debug("ECDSA signature check failed: %s", gpg_strerror(ge));
+                k = -EIO;
+        } else
+                k = 1;
+finish:
+        if (r)
+                gcry_mpi_release(r);
+        if (s)
+                gcry_mpi_release(s);
+        if (q)
+                gcry_mpi_release(q);
+
+        if (public_key_sexp)
+                gcry_sexp_release(public_key_sexp);
+        if (signature_sexp)
+                gcry_sexp_release(signature_sexp);
+        if (data_sexp)
+                gcry_sexp_release(data_sexp);
+
+        return k;
+}
+
+static int dnssec_ecdsa_verify(
+                const char *hash_algorithm,
+                int algorithm,
+                const void *hash, size_t hash_size,
+                DnsResourceRecord *rrsig,
+                DnsResourceRecord *dnskey) {
+
+        const char *curve;
+        size_t key_size;
+        uint8_t *q;
+
+        assert(hash);
+        assert(hash_size);
+        assert(rrsig);
+        assert(dnskey);
+
+        if (algorithm == DNSSEC_ALGORITHM_ECDSAP256SHA256) {
+                key_size = 32;
+                curve = "NIST P-256";
+        } else if (algorithm == DNSSEC_ALGORITHM_ECDSAP384SHA384) {
+                key_size = 48;
+                curve = "NIST P-384";
+        } else
+                return -EOPNOTSUPP;
+
+        if (dnskey->dnskey.key_size != key_size * 2)
+                return -EINVAL;
+
+        if (rrsig->rrsig.signature_size != key_size * 2)
+                return -EINVAL;
+
+        q = alloca(key_size*2 + 1);
+        q[0] = 0x04; /* Prepend 0x04 to indicate an uncompressed key */
+        memcpy(q+1, dnskey->dnskey.key, key_size*2);
+
+        return dnssec_ecdsa_verify_raw(
+                        hash_algorithm,
+                        curve,
+                        rrsig->rrsig.signature, key_size,
+                        (uint8_t*) rrsig->rrsig.signature + key_size, key_size,
+                        hash, hash_size,
+                        q, key_size*2+1);
+}
+
+static void md_add_uint8(gcry_md_hd_t md, uint8_t v) {
+        gcry_md_write(md, &v, sizeof(v));
+}
+
+static void md_add_uint16(gcry_md_hd_t md, uint16_t v) {
+        v = htobe16(v);
+        gcry_md_write(md, &v, sizeof(v));
+}
+
+static void md_add_uint32(gcry_md_hd_t md, uint32_t v) {
+        v = htobe32(v);
+        gcry_md_write(md, &v, sizeof(v));
+}
+
+static int dnssec_rrsig_prepare(DnsResourceRecord *rrsig) {
+        int n_key_labels, n_signer_labels;
+        const char *name;
+        int r;
+
+        /* Checks whether the specified RRSIG RR is somewhat valid, and initializes the .n_skip_labels_source and
+         * .n_skip_labels_signer fields so that we can use them later on. */
+
+        assert(rrsig);
+        assert(rrsig->key->type == DNS_TYPE_RRSIG);
+
+        /* Check if this RRSIG RR is already prepared */
+        if (rrsig->n_skip_labels_source != (unsigned) -1)
+                return 0;
+
+        if (rrsig->rrsig.inception > rrsig->rrsig.expiration)
+                return -EINVAL;
+
+        name = dns_resource_key_name(rrsig->key);
+
+        n_key_labels = dns_name_count_labels(name);
+        if (n_key_labels < 0)
+                return n_key_labels;
+        if (rrsig->rrsig.labels > n_key_labels)
+                return -EINVAL;
+
+        n_signer_labels = dns_name_count_labels(rrsig->rrsig.signer);
+        if (n_signer_labels < 0)
+                return n_signer_labels;
+        if (n_signer_labels > rrsig->rrsig.labels)
+                return -EINVAL;
+
+        r = dns_name_skip(name, n_key_labels - n_signer_labels, &name);
+        if (r < 0)
+                return r;
+        if (r == 0)
+                return -EINVAL;
+
+        /* Check if the signer is really a suffix of us */
+        r = dns_name_equal(name, rrsig->rrsig.signer);
+        if (r < 0)
+                return r;
+        if (r == 0)
+                return -EINVAL;
+
+        rrsig->n_skip_labels_source = n_key_labels - rrsig->rrsig.labels;
+        rrsig->n_skip_labels_signer = n_key_labels - n_signer_labels;
+
+        return 0;
+}
+
+static int dnssec_rrsig_expired(DnsResourceRecord *rrsig, usec_t realtime) {
+        usec_t expiration, inception, skew;
+
+        assert(rrsig);
+        assert(rrsig->key->type == DNS_TYPE_RRSIG);
+
+        if (realtime == USEC_INFINITY)
+                realtime = now(CLOCK_REALTIME);
+
+        expiration = rrsig->rrsig.expiration * USEC_PER_SEC;
+        inception = rrsig->rrsig.inception * USEC_PER_SEC;
+
+        /* Consider inverted validity intervals as expired */
+        if (inception > expiration)
+                return true;
+
+        /* Permit a certain amount of clock skew of 10% of the valid
+         * time range. This takes inspiration from unbound's
+         * resolver. */
+        skew = (expiration - inception) / 10;
+        if (skew > SKEW_MAX)
+                skew = SKEW_MAX;
+
+        if (inception < skew)
+                inception = 0;
+        else
+                inception -= skew;
+
+        if (expiration + skew < expiration)
+                expiration = USEC_INFINITY;
+        else
+                expiration += skew;
+
+        return realtime < inception || realtime > expiration;
+}
+
+static int algorithm_to_gcrypt_md(uint8_t algorithm) {
+
+        /* Translates a DNSSEC signature algorithm into a gcrypt
+         * digest identifier.
+         *
+         * Note that we implement all algorithms listed as "Must
+         * implement" and "Recommended to Implement" in RFC6944. We
+         * don't implement any algorithms that are listed as
+         * "Optional" or "Must Not Implement". Specifically, we do not
+         * implement RSAMD5, DSASHA1, DH, DSA-NSEC3-SHA1, and
+         * GOST-ECC. */
+
+        switch (algorithm) {
+
+        case DNSSEC_ALGORITHM_RSASHA1:
+        case DNSSEC_ALGORITHM_RSASHA1_NSEC3_SHA1:
+                return GCRY_MD_SHA1;
+
+        case DNSSEC_ALGORITHM_RSASHA256:
+        case DNSSEC_ALGORITHM_ECDSAP256SHA256:
+                return GCRY_MD_SHA256;
+
+        case DNSSEC_ALGORITHM_ECDSAP384SHA384:
+                return GCRY_MD_SHA384;
+
+        case DNSSEC_ALGORITHM_RSASHA512:
+                return GCRY_MD_SHA512;
+
+        default:
+                return -EOPNOTSUPP;
+        }
+}
+
+static void dnssec_fix_rrset_ttl(
+                DnsResourceRecord *list[],
+                unsigned n,
+                DnsResourceRecord *rrsig,
+                usec_t realtime) {
+
+        unsigned k;
+
+        assert(list);
+        assert(n > 0);
+        assert(rrsig);
+
+        for (k = 0; k < n; k++) {
+                DnsResourceRecord *rr = list[k];
+
+                /* Pick the TTL as the minimum of the RR's TTL, the
+                 * RR's original TTL according to the RRSIG and the
+                 * RRSIG's own TTL, see RFC 4035, Section 5.3.3 */
+                rr->ttl = MIN3(rr->ttl, rrsig->rrsig.original_ttl, rrsig->ttl);
+                rr->expiry = rrsig->rrsig.expiration * USEC_PER_SEC;
+
+                /* Copy over information about the signer and wildcard source of synthesis */
+                rr->n_skip_labels_source = rrsig->n_skip_labels_source;
+                rr->n_skip_labels_signer = rrsig->n_skip_labels_signer;
+        }
+
+        rrsig->expiry = rrsig->rrsig.expiration * USEC_PER_SEC;
+}
+
+int dnssec_verify_rrset(
+                DnsAnswer *a,
+                const DnsResourceKey *key,
+                DnsResourceRecord *rrsig,
+                DnsResourceRecord *dnskey,
+                usec_t realtime,
+                DnssecResult *result) {
+
+        uint8_t wire_format_name[DNS_WIRE_FOMAT_HOSTNAME_MAX];
+        DnsResourceRecord **list, *rr;
+        const char *source, *name;
+        gcry_md_hd_t md = NULL;
+        int r, md_algorithm;
+        size_t k, n = 0;
+        size_t hash_size;
+        void *hash;
+        bool wildcard;
+
+        assert(key);
+        assert(rrsig);
+        assert(dnskey);
+        assert(result);
+        assert(rrsig->key->type == DNS_TYPE_RRSIG);
+        assert(dnskey->key->type == DNS_TYPE_DNSKEY);
+
+        /* Verifies that the RRSet matches the specified "key" in "a",
+         * using the signature "rrsig" and the key "dnskey". It's
+         * assumed that RRSIG and DNSKEY match. */
+
+        md_algorithm = algorithm_to_gcrypt_md(rrsig->rrsig.algorithm);
+        if (md_algorithm == -EOPNOTSUPP) {
+                *result = DNSSEC_UNSUPPORTED_ALGORITHM;
+                return 0;
+        }
+        if (md_algorithm < 0)
+                return md_algorithm;
+
+        r = dnssec_rrsig_prepare(rrsig);
+        if (r == -EINVAL) {
+                *result = DNSSEC_INVALID;
+                return r;
+        }
+        if (r < 0)
+                return r;
+
+        r = dnssec_rrsig_expired(rrsig, realtime);
+        if (r < 0)
+                return r;
+        if (r > 0) {
+                *result = DNSSEC_SIGNATURE_EXPIRED;
+                return 0;
+        }
+
+        name = dns_resource_key_name(key);
+
+        /* Some keys may only appear signed in the zone apex, and are invalid anywhere else. (SOA, NS...) */
+        if (dns_type_apex_only(rrsig->rrsig.type_covered)) {
+                r = dns_name_equal(rrsig->rrsig.signer, name);
+                if (r < 0)
+                        return r;
+                if (r == 0) {
+                        *result = DNSSEC_INVALID;
+                        return 0;
+                }
+        }
+
+        /* OTOH DS RRs may not appear in the zone apex, but are valid everywhere else. */
+        if (rrsig->rrsig.type_covered == DNS_TYPE_DS) {
+                r = dns_name_equal(rrsig->rrsig.signer, name);
+                if (r < 0)
+                        return r;
+                if (r > 0) {
+                        *result = DNSSEC_INVALID;
+                        return 0;
+                }
+        }
+
+        /* Determine the "Source of Synthesis" and whether this is a wildcard RRSIG */
+        r = dns_name_suffix(name, rrsig->rrsig.labels, &source);
+        if (r < 0)
+                return r;
+        if (r > 0 && !dns_type_may_wildcard(rrsig->rrsig.type_covered)) {
+                /* We refuse to validate NSEC3 or SOA RRs that are synthesized from wildcards */
+                *result = DNSSEC_INVALID;
+                return 0;
+        }
+        if (r == 1) {
+                /* If we stripped a single label, then let's see if that maybe was "*". If so, we are not really
+                 * synthesized from a wildcard, we are the wildcard itself. Treat that like a normal name. */
+                r = dns_name_startswith(name, "*");
+                if (r < 0)
+                        return r;
+                if (r > 0)
+                        source = name;
+
+                wildcard = r == 0;
+        } else
+                wildcard = r > 0;
+
+        /* Collect all relevant RRs in a single array, so that we can look at the RRset */
+        list = newa(DnsResourceRecord *, dns_answer_size(a));
+
+        DNS_ANSWER_FOREACH(rr, a) {
+                r = dns_resource_key_equal(key, rr->key);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        continue;
+
+                /* We need the wire format for ordering, and digest calculation */
+                r = dns_resource_record_to_wire_format(rr, true);
+                if (r < 0)
+                        return r;
+
+                list[n++] = rr;
+
+                if (n > VERIFY_RRS_MAX)
+                        return -E2BIG;
+        }
+
+        if (n <= 0)
+                return -ENODATA;
+
+        /* Bring the RRs into canonical order */
+        qsort_safe(list, n, sizeof(DnsResourceRecord*), rr_compare);
+
+        /* OK, the RRs are now in canonical order. Let's calculate the digest */
+        initialize_libgcrypt(false);
+
+        hash_size = gcry_md_get_algo_dlen(md_algorithm);
+        assert(hash_size > 0);
+
+        gcry_md_open(&md, md_algorithm, 0);
+        if (!md)
+                return -EIO;
+
+        md_add_uint16(md, rrsig->rrsig.type_covered);
+        md_add_uint8(md, rrsig->rrsig.algorithm);
+        md_add_uint8(md, rrsig->rrsig.labels);
+        md_add_uint32(md, rrsig->rrsig.original_ttl);
+        md_add_uint32(md, rrsig->rrsig.expiration);
+        md_add_uint32(md, rrsig->rrsig.inception);
+        md_add_uint16(md, rrsig->rrsig.key_tag);
+
+        r = dns_name_to_wire_format(rrsig->rrsig.signer, wire_format_name, sizeof(wire_format_name), true);
+        if (r < 0)
+                goto finish;
+        gcry_md_write(md, wire_format_name, r);
+
+        /* Convert the source of synthesis into wire format */
+        r = dns_name_to_wire_format(source, wire_format_name, sizeof(wire_format_name), true);
+        if (r < 0)
+                goto finish;
+
+        for (k = 0; k < n; k++) {
+                size_t l;
+
+                rr = list[k];
+
+                /* Hash the source of synthesis. If this is a wildcard, then prefix it with the *. label */
+                if (wildcard)
+                        gcry_md_write(md, (uint8_t[]) { 1, '*'}, 2);
+                gcry_md_write(md, wire_format_name, r);
+
+                md_add_uint16(md, rr->key->type);
+                md_add_uint16(md, rr->key->class);
+                md_add_uint32(md, rrsig->rrsig.original_ttl);
+
+                l = DNS_RESOURCE_RECORD_RDATA_SIZE(rr);
+                assert(l <= 0xFFFF);
+
+                md_add_uint16(md, (uint16_t) l);
+                gcry_md_write(md, DNS_RESOURCE_RECORD_RDATA(rr), l);
+        }
+
+        hash = gcry_md_read(md, 0);
+        if (!hash) {
+                r = -EIO;
+                goto finish;
+        }
+
+        switch (rrsig->rrsig.algorithm) {
+
+        case DNSSEC_ALGORITHM_RSASHA1:
+        case DNSSEC_ALGORITHM_RSASHA1_NSEC3_SHA1:
+        case DNSSEC_ALGORITHM_RSASHA256:
+        case DNSSEC_ALGORITHM_RSASHA512:
+                r = dnssec_rsa_verify(
+                                gcry_md_algo_name(md_algorithm),
+                                hash, hash_size,
+                                rrsig,
+                                dnskey);
+                break;
+
+        case DNSSEC_ALGORITHM_ECDSAP256SHA256:
+        case DNSSEC_ALGORITHM_ECDSAP384SHA384:
+                r = dnssec_ecdsa_verify(
+                                gcry_md_algo_name(md_algorithm),
+                                rrsig->rrsig.algorithm,
+                                hash, hash_size,
+                                rrsig,
+                                dnskey);
+                break;
+        }
+
+        if (r < 0)
+                goto finish;
+
+        /* Now, fix the ttl, expiry, and remember the synthesizing source and the signer */
+        if (r > 0)
+                dnssec_fix_rrset_ttl(list, n, rrsig, realtime);
+
+        if (r == 0)
+                *result = DNSSEC_INVALID;
+        else if (wildcard)
+                *result = DNSSEC_VALIDATED_WILDCARD;
+        else
+                *result = DNSSEC_VALIDATED;
+
+        r = 0;
+
+finish:
+        gcry_md_close(md);
+        return r;
+}
+
+int dnssec_rrsig_match_dnskey(DnsResourceRecord *rrsig, DnsResourceRecord *dnskey, bool revoked_ok) {
+
+        assert(rrsig);
+        assert(dnskey);
+
+        /* Checks if the specified DNSKEY RR matches the key used for
+         * the signature in the specified RRSIG RR */
+
+        if (rrsig->key->type != DNS_TYPE_RRSIG)
+                return -EINVAL;
+
+        if (dnskey->key->type != DNS_TYPE_DNSKEY)
+                return 0;
+        if (dnskey->key->class != rrsig->key->class)
+                return 0;
+        if ((dnskey->dnskey.flags & DNSKEY_FLAG_ZONE_KEY) == 0)
+                return 0;
+        if (!revoked_ok && (dnskey->dnskey.flags & DNSKEY_FLAG_REVOKE))
+                return 0;
+        if (dnskey->dnskey.protocol != 3)
+                return 0;
+        if (dnskey->dnskey.algorithm != rrsig->rrsig.algorithm)
+                return 0;
+
+        if (dnssec_keytag(dnskey, false) != rrsig->rrsig.key_tag)
+                return 0;
+
+        return dns_name_equal(dns_resource_key_name(dnskey->key), rrsig->rrsig.signer);
+}
+
+int dnssec_key_match_rrsig(const DnsResourceKey *key, DnsResourceRecord *rrsig) {
+        assert(key);
+        assert(rrsig);
+
+        /* Checks if the specified RRSIG RR protects the RRSet of the specified RR key. */
+
+        if (rrsig->key->type != DNS_TYPE_RRSIG)
+                return 0;
+        if (rrsig->key->class != key->class)
+                return 0;
+        if (rrsig->rrsig.type_covered != key->type)
+                return 0;
+
+        return dns_name_equal(dns_resource_key_name(rrsig->key), dns_resource_key_name(key));
+}
+
+int dnssec_verify_rrset_search(
+                DnsAnswer *a,
+                const DnsResourceKey *key,
+                DnsAnswer *validated_dnskeys,
+                usec_t realtime,
+                DnssecResult *result,
+                DnsResourceRecord **ret_rrsig) {
+
+        bool found_rrsig = false, found_invalid = false, found_expired_rrsig = false, found_unsupported_algorithm = false;
+        DnsResourceRecord *rrsig;
+        int r;
+
+        assert(key);
+        assert(result);
+
+        /* Verifies all RRs from "a" that match the key "key" against DNSKEYs in "validated_dnskeys" */
+
+        if (!a || a->n_rrs <= 0)
+                return -ENODATA;
+
+        /* Iterate through each RRSIG RR. */
+        DNS_ANSWER_FOREACH(rrsig, a) {
+                DnsResourceRecord *dnskey;
+                DnsAnswerFlags flags;
+
+                /* Is this an RRSIG RR that applies to RRs matching our key? */
+                r = dnssec_key_match_rrsig(key, rrsig);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        continue;
+
+                found_rrsig = true;
+
+                /* Look for a matching key */
+                DNS_ANSWER_FOREACH_FLAGS(dnskey, flags, validated_dnskeys) {
+                        DnssecResult one_result;
+
+                        if ((flags & DNS_ANSWER_AUTHENTICATED) == 0)
+                                continue;
+
+                        /* Is this a DNSKEY RR that matches they key of our RRSIG? */
+                        r = dnssec_rrsig_match_dnskey(rrsig, dnskey, false);
+                        if (r < 0)
+                                return r;
+                        if (r == 0)
+                                continue;
+
+                        /* Take the time here, if it isn't set yet, so
+                         * that we do all validations with the same
+                         * time. */
+                        if (realtime == USEC_INFINITY)
+                                realtime = now(CLOCK_REALTIME);
+
+                        /* Yay, we found a matching RRSIG with a matching
+                         * DNSKEY, awesome. Now let's verify all entries of
+                         * the RRSet against the RRSIG and DNSKEY
+                         * combination. */
+
+                        r = dnssec_verify_rrset(a, key, rrsig, dnskey, realtime, &one_result);
+                        if (r < 0)
+                                return r;
+
+                        switch (one_result) {
+
+                        case DNSSEC_VALIDATED:
+                        case DNSSEC_VALIDATED_WILDCARD:
+                                /* Yay, the RR has been validated,
+                                 * return immediately, but fix up the expiry */
+                                if (ret_rrsig)
+                                        *ret_rrsig = rrsig;
+
+                                *result = one_result;
+                                return 0;
+
+                        case DNSSEC_INVALID:
+                                /* If the signature is invalid, let's try another
+                                   key and/or signature. After all they
+                                   key_tags and stuff are not unique, and
+                                   might be shared by multiple keys. */
+                                found_invalid = true;
+                                continue;
+
+                        case DNSSEC_UNSUPPORTED_ALGORITHM:
+                                /* If the key algorithm is
+                                   unsupported, try another
+                                   RRSIG/DNSKEY pair, but remember we
+                                   encountered this, so that we can
+                                   return a proper error when we
+                                   encounter nothing better. */
+                                found_unsupported_algorithm = true;
+                                continue;
+
+                        case DNSSEC_SIGNATURE_EXPIRED:
+                                /* If the signature is expired, try
+                                   another one, but remember it, so
+                                   that we can return this */
+                                found_expired_rrsig = true;
+                                continue;
+
+                        default:
+                                assert_not_reached("Unexpected DNSSEC validation result");
+                        }
+                }
+        }
+
+        if (found_expired_rrsig)
+                *result = DNSSEC_SIGNATURE_EXPIRED;
+        else if (found_unsupported_algorithm)
+                *result = DNSSEC_UNSUPPORTED_ALGORITHM;
+        else if (found_invalid)
+                *result = DNSSEC_INVALID;
+        else if (found_rrsig)
+                *result = DNSSEC_MISSING_KEY;
+        else
+                *result = DNSSEC_NO_SIGNATURE;
+
+        if (ret_rrsig)
+                *ret_rrsig = NULL;
+
+        return 0;
+}
+
+int dnssec_has_rrsig(DnsAnswer *a, const DnsResourceKey *key) {
+        DnsResourceRecord *rr;
+        int r;
+
+        /* Checks whether there's at least one RRSIG in 'a' that proctects RRs of the specified key */
+
+        DNS_ANSWER_FOREACH(rr, a) {
+                r = dnssec_key_match_rrsig(key, rr);
+                if (r < 0)
+                        return r;
+                if (r > 0)
+                        return 1;
+        }
+
+        return 0;
+}
+
+static int digest_to_gcrypt_md(uint8_t algorithm) {
+
+        /* Translates a DNSSEC digest algorithm into a gcrypt digest identifier */
+
+        switch (algorithm) {
+
+        case DNSSEC_DIGEST_SHA1:
+                return GCRY_MD_SHA1;
+
+        case DNSSEC_DIGEST_SHA256:
+                return GCRY_MD_SHA256;
+
+        case DNSSEC_DIGEST_SHA384:
+                return GCRY_MD_SHA384;
+
+        default:
+                return -EOPNOTSUPP;
+        }
+}
+
+int dnssec_verify_dnskey_by_ds(DnsResourceRecord *dnskey, DnsResourceRecord *ds, bool mask_revoke) {
+        char owner_name[DNSSEC_CANONICAL_HOSTNAME_MAX];
+        gcry_md_hd_t md = NULL;
+        size_t hash_size;
+        int md_algorithm, r;
+        void *result;
+
+        assert(dnskey);
+        assert(ds);
+
+        /* Implements DNSKEY verification by a DS, according to RFC 4035, section 5.2 */
+
+        if (dnskey->key->type != DNS_TYPE_DNSKEY)
+                return -EINVAL;
+        if (ds->key->type != DNS_TYPE_DS)
+                return -EINVAL;
+        if ((dnskey->dnskey.flags & DNSKEY_FLAG_ZONE_KEY) == 0)
+                return -EKEYREJECTED;
+        if (!mask_revoke && (dnskey->dnskey.flags & DNSKEY_FLAG_REVOKE))
+                return -EKEYREJECTED;
+        if (dnskey->dnskey.protocol != 3)
+                return -EKEYREJECTED;
+
+        if (dnskey->dnskey.algorithm != ds->ds.algorithm)
+                return 0;
+        if (dnssec_keytag(dnskey, mask_revoke) != ds->ds.key_tag)
+                return 0;
+
+        initialize_libgcrypt(false);
+
+        md_algorithm = digest_to_gcrypt_md(ds->ds.digest_type);
+        if (md_algorithm < 0)
+                return md_algorithm;
+
+        hash_size = gcry_md_get_algo_dlen(md_algorithm);
+        assert(hash_size > 0);
+
+        if (ds->ds.digest_size != hash_size)
+                return 0;
+
+        r = dnssec_canonicalize(dns_resource_key_name(dnskey->key), owner_name, sizeof(owner_name));
+        if (r < 0)
+                return r;
+
+        gcry_md_open(&md, md_algorithm, 0);
+        if (!md)
+                return -EIO;
+
+        gcry_md_write(md, owner_name, r);
+        if (mask_revoke)
+                md_add_uint16(md, dnskey->dnskey.flags & ~DNSKEY_FLAG_REVOKE);
+        else
+                md_add_uint16(md, dnskey->dnskey.flags);
+        md_add_uint8(md, dnskey->dnskey.protocol);
+        md_add_uint8(md, dnskey->dnskey.algorithm);
+        gcry_md_write(md, dnskey->dnskey.key, dnskey->dnskey.key_size);
+
+        result = gcry_md_read(md, 0);
+        if (!result) {
+                r = -EIO;
+                goto finish;
+        }
+
+        r = memcmp(result, ds->ds.digest, ds->ds.digest_size) != 0;
+
+finish:
+        gcry_md_close(md);
+        return r;
+}
+
+int dnssec_verify_dnskey_by_ds_search(DnsResourceRecord *dnskey, DnsAnswer *validated_ds) {
+        DnsResourceRecord *ds;
+        DnsAnswerFlags flags;
+        int r;
+
+        assert(dnskey);
+
+        if (dnskey->key->type != DNS_TYPE_DNSKEY)
+                return 0;
+
+        DNS_ANSWER_FOREACH_FLAGS(ds, flags, validated_ds) {
+
+                if ((flags & DNS_ANSWER_AUTHENTICATED) == 0)
+                        continue;
+
+                if (ds->key->type != DNS_TYPE_DS)
+                        continue;
+                if (ds->key->class != dnskey->key->class)
+                        continue;
+
+                r = dns_name_equal(dns_resource_key_name(dnskey->key), dns_resource_key_name(ds->key));
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        continue;
+
+                r = dnssec_verify_dnskey_by_ds(dnskey, ds, false);
+                if (IN_SET(r, -EKEYREJECTED, -EOPNOTSUPP))
+                        return 0; /* The DNSKEY is revoked or otherwise invalid, or we don't support the digest algorithm */
+                if (r < 0)
+                        return r;
+                if (r > 0)
+                        return 1;
+        }
+
+        return 0;
+}
+
+static int nsec3_hash_to_gcrypt_md(uint8_t algorithm) {
+
+        /* Translates a DNSSEC NSEC3 hash algorithm into a gcrypt digest identifier */
+
+        switch (algorithm) {
+
+        case NSEC3_ALGORITHM_SHA1:
+                return GCRY_MD_SHA1;
+
+        default:
+                return -EOPNOTSUPP;
+        }
+}
+
+int dnssec_nsec3_hash(DnsResourceRecord *nsec3, const char *name, void *ret) {
+        uint8_t wire_format[DNS_WIRE_FOMAT_HOSTNAME_MAX];
+        gcry_md_hd_t md = NULL;
+        size_t hash_size;
+        int algorithm;
+        void *result;
+        unsigned k;
+        int r;
+
+        assert(nsec3);
+        assert(name);
+        assert(ret);
+
+        if (nsec3->key->type != DNS_TYPE_NSEC3)
+                return -EINVAL;
+
+        if (nsec3->nsec3.iterations > NSEC3_ITERATIONS_MAX) {
+                log_debug("Ignoring NSEC3 RR %s with excessive number of iterations.", dns_resource_record_to_string(nsec3));
+                return -EOPNOTSUPP;
+        }
+
+        algorithm = nsec3_hash_to_gcrypt_md(nsec3->nsec3.algorithm);
+        if (algorithm < 0)
+                return algorithm;
+
+        initialize_libgcrypt(false);
+
+        hash_size = gcry_md_get_algo_dlen(algorithm);
+        assert(hash_size > 0);
+
+        if (nsec3->nsec3.next_hashed_name_size != hash_size)
+                return -EINVAL;
+
+        r = dns_name_to_wire_format(name, wire_format, sizeof(wire_format), true);
+        if (r < 0)
+                return r;
+
+        gcry_md_open(&md, algorithm, 0);
+        if (!md)
+                return -EIO;
+
+        gcry_md_write(md, wire_format, r);
+        gcry_md_write(md, nsec3->nsec3.salt, nsec3->nsec3.salt_size);
+
+        result = gcry_md_read(md, 0);
+        if (!result) {
+                r = -EIO;
+                goto finish;
+        }
+
+        for (k = 0; k < nsec3->nsec3.iterations; k++) {
+                uint8_t tmp[hash_size];
+                memcpy(tmp, result, hash_size);
+
+                gcry_md_reset(md);
+                gcry_md_write(md, tmp, hash_size);
+                gcry_md_write(md, nsec3->nsec3.salt, nsec3->nsec3.salt_size);
+
+                result = gcry_md_read(md, 0);
+                if (!result) {
+                        r = -EIO;
+                        goto finish;
+                }
+        }
+
+        memcpy(ret, result, hash_size);
+        r = (int) hash_size;
+
+finish:
+        gcry_md_close(md);
+        return r;
+}
+
+static int nsec3_is_good(DnsResourceRecord *rr, DnsResourceRecord *nsec3) {
+        const char *a, *b;
+        int r;
+
+        assert(rr);
+
+        if (rr->key->type != DNS_TYPE_NSEC3)
+                return 0;
+
+        /* RFC 5155, Section 8.2 says we MUST ignore NSEC3 RRs with flags != 0 or 1 */
+        if (!IN_SET(rr->nsec3.flags, 0, 1))
+                return 0;
+
+        /* Ignore NSEC3 RRs whose algorithm we don't know */
+        if (nsec3_hash_to_gcrypt_md(rr->nsec3.algorithm) < 0)
+                return 0;
+        /* Ignore NSEC3 RRs with an excessive number of required iterations */
+        if (rr->nsec3.iterations > NSEC3_ITERATIONS_MAX)
+                return 0;
+
+        /* Ignore NSEC3 RRs generated from wildcards. If these NSEC3 RRs weren't correctly signed we can't make this
+         * check (since rr->n_skip_labels_source is -1), but that's OK, as we won't trust them anyway in that case. */
+        if (rr->n_skip_labels_source != 0 && rr->n_skip_labels_source != (unsigned) -1)
+                return 0;
+        /* Ignore NSEC3 RRs that are located anywhere else than one label below the zone */
+        if (rr->n_skip_labels_signer != 1 && rr->n_skip_labels_signer != (unsigned) -1)
+                return 0;
+
+        if (!nsec3)
+                return 1;
+
+        /* If a second NSEC3 RR is specified, also check if they are from the same zone. */
+
+        if (nsec3 == rr) /* Shortcut */
+                return 1;
+
+        if (rr->key->class != nsec3->key->class)
+                return 0;
+        if (rr->nsec3.algorithm != nsec3->nsec3.algorithm)
+                return 0;
+        if (rr->nsec3.iterations != nsec3->nsec3.iterations)
+                return 0;
+        if (rr->nsec3.salt_size != nsec3->nsec3.salt_size)
+                return 0;
+        if (memcmp(rr->nsec3.salt, nsec3->nsec3.salt, rr->nsec3.salt_size) != 0)
+                return 0;
+
+        a = dns_resource_key_name(rr->key);
+        r = dns_name_parent(&a); /* strip off hash */
+        if (r < 0)
+                return r;
+        if (r == 0)
+                return 0;
+
+        b = dns_resource_key_name(nsec3->key);
+        r = dns_name_parent(&b); /* strip off hash */
+        if (r < 0)
+                return r;
+        if (r == 0)
+                return 0;
+
+        /* Make sure both have the same parent */
+        return dns_name_equal(a, b);
+}
+
+static int nsec3_hashed_domain_format(const uint8_t *hashed, size_t hashed_size, const char *zone, char **ret) {
+        _cleanup_free_ char *l = NULL;
+        char *j;
+
+        assert(hashed);
+        assert(hashed_size > 0);
+        assert(zone);
+        assert(ret);
+
+        l = base32hexmem(hashed, hashed_size, false);
+        if (!l)
+                return -ENOMEM;
+
+        j = strjoin(l, ".", zone, NULL);
+        if (!j)
+                return -ENOMEM;
+
+        *ret = j;
+        return (int) hashed_size;
+}
+
+static int nsec3_hashed_domain_make(DnsResourceRecord *nsec3, const char *domain, const char *zone, char **ret) {
+        uint8_t hashed[DNSSEC_HASH_SIZE_MAX];
+        int hashed_size;
+
+        assert(nsec3);
+        assert(domain);
+        assert(zone);
+        assert(ret);
+
+        hashed_size = dnssec_nsec3_hash(nsec3, domain, hashed);
+        if (hashed_size < 0)
+                return hashed_size;
+
+        return nsec3_hashed_domain_format(hashed, (size_t) hashed_size, zone, ret);
+}
+
+/* See RFC 5155, Section 8
+ * First try to find a NSEC3 record that matches our query precisely, if that fails, find the closest
+ * enclosure. Secondly, find a proof that there is no closer enclosure and either a proof that there
+ * is no wildcard domain as a direct descendant of the closest enclosure, or find an NSEC3 record that
+ * matches the wildcard domain.
+ *
+ * Based on this we can prove either the existence of the record in @key, or NXDOMAIN or NODATA, or
+ * that there is no proof either way. The latter is the case if a the proof of non-existence of a given
+ * name uses an NSEC3 record with the opt-out bit set. Lastly, if we are given insufficient NSEC3 records
+ * to conclude anything we indicate this by returning NO_RR. */
+static int dnssec_test_nsec3(DnsAnswer *answer, DnsResourceKey *key, DnssecNsecResult *result, bool *authenticated, uint32_t *ttl) {
+        _cleanup_free_ char *next_closer_domain = NULL, *wildcard_domain = NULL;
+        const char *zone, *p, *pp = NULL, *wildcard;
+        DnsResourceRecord *rr, *enclosure_rr, *zone_rr, *wildcard_rr = NULL;
+        DnsAnswerFlags flags;
+        int hashed_size, r;
+        bool a, no_closer = false, no_wildcard = false, optout = false;
+
+        assert(key);
+        assert(result);
+
+        /* First step, find the zone name and the NSEC3 parameters of the zone.
+         * it is sufficient to look for the longest common suffix we find with
+         * any NSEC3 RR in the response. Any NSEC3 record will do as all NSEC3
+         * records from a given zone in a response must use the same
+         * parameters. */
+        zone = dns_resource_key_name(key);
+        for (;;) {
+                DNS_ANSWER_FOREACH_FLAGS(zone_rr, flags, answer) {
+                        r = nsec3_is_good(zone_rr, NULL);
+                        if (r < 0)
+                                return r;
+                        if (r == 0)
+                                continue;
+
+                        r = dns_name_equal_skip(dns_resource_key_name(zone_rr->key), 1, zone);
+                        if (r < 0)
+                                return r;
+                        if (r > 0)
+                                goto found_zone;
+                }
+
+                /* Strip one label from the front */
+                r = dns_name_parent(&zone);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        break;
+        }
+
+        *result = DNSSEC_NSEC_NO_RR;
+        return 0;
+
+found_zone:
+        /* Second step, find the closest encloser NSEC3 RR in 'answer' that matches 'key' */
+        p = dns_resource_key_name(key);
+        for (;;) {
+                _cleanup_free_ char *hashed_domain = NULL;
+
+                hashed_size = nsec3_hashed_domain_make(zone_rr, p, zone, &hashed_domain);
+                if (hashed_size == -EOPNOTSUPP) {
+                        *result = DNSSEC_NSEC_UNSUPPORTED_ALGORITHM;
+                        return 0;
+                }
+                if (hashed_size < 0)
+                        return hashed_size;
+
+                DNS_ANSWER_FOREACH_FLAGS(enclosure_rr, flags, answer) {
+
+                        r = nsec3_is_good(enclosure_rr, zone_rr);
+                        if (r < 0)
+                                return r;
+                        if (r == 0)
+                                continue;
+
+                        if (enclosure_rr->nsec3.next_hashed_name_size != (size_t) hashed_size)
+                                continue;
+
+                        r = dns_name_equal(dns_resource_key_name(enclosure_rr->key), hashed_domain);
+                        if (r < 0)
+                                return r;
+                        if (r > 0) {
+                                a = flags & DNS_ANSWER_AUTHENTICATED;
+                                goto found_closest_encloser;
+                        }
+                }
+
+                /* We didn't find the closest encloser with this name,
+                 * but let's remember this domain name, it might be
+                 * the next closer name */
+
+                pp = p;
+
+                /* Strip one label from the front */
+                r = dns_name_parent(&p);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        break;
+        }
+
+        *result = DNSSEC_NSEC_NO_RR;
+        return 0;
+
+found_closest_encloser:
+        /* We found a closest encloser in 'p'; next closer is 'pp' */
+
+        if (!pp) {
+                /* We have an exact match! If we area looking for a DS RR, then we must insist that we got the NSEC3 RR
+                 * from the parent. Otherwise the one from the child. Do so, by checking whether SOA and NS are
+                 * appropriately set. */
+
+                if (key->type == DNS_TYPE_DS) {
+                        if (bitmap_isset(enclosure_rr->nsec3.types, DNS_TYPE_SOA))
+                                return -EBADMSG;
+                } else {
+                        if (bitmap_isset(enclosure_rr->nsec3.types, DNS_TYPE_NS) &&
+                            !bitmap_isset(enclosure_rr->nsec3.types, DNS_TYPE_SOA))
+                                return -EBADMSG;
+                }
+
+                /* No next closer NSEC3 RR. That means there's a direct NSEC3 RR for our key. */
+                if (bitmap_isset(enclosure_rr->nsec3.types, key->type))
+                        *result = DNSSEC_NSEC_FOUND;
+                else if (bitmap_isset(enclosure_rr->nsec3.types, DNS_TYPE_CNAME))
+                        *result = DNSSEC_NSEC_CNAME;
+                else
+                        *result = DNSSEC_NSEC_NODATA;
+
+                if (authenticated)
+                        *authenticated = a;
+                if (ttl)
+                        *ttl = enclosure_rr->ttl;
+
+                return 0;
+        }
+
+        /* Ensure this is not a DNAME domain, see RFC5155, section 8.3. */
+        if (bitmap_isset(enclosure_rr->nsec3.types, DNS_TYPE_DNAME))
+                return -EBADMSG;
+
+        /* Ensure that this data is from the delegated domain
+         * (i.e. originates from the "lower" DNS server), and isn't
+         * just glue records (i.e. doesn't originate from the "upper"
+         * DNS server). */
+        if (bitmap_isset(enclosure_rr->nsec3.types, DNS_TYPE_NS) &&
+            !bitmap_isset(enclosure_rr->nsec3.types, DNS_TYPE_SOA))
+                return -EBADMSG;
+
+        /* Prove that there is no next closer and whether or not there is a wildcard domain. */
+
+        wildcard = strjoina("*.", p);
+        r = nsec3_hashed_domain_make(enclosure_rr, wildcard, zone, &wildcard_domain);
+        if (r < 0)
+                return r;
+        if (r != hashed_size)
+                return -EBADMSG;
+
+        r = nsec3_hashed_domain_make(enclosure_rr, pp, zone, &next_closer_domain);
+        if (r < 0)
+                return r;
+        if (r != hashed_size)
+                return -EBADMSG;
+
+        DNS_ANSWER_FOREACH_FLAGS(rr, flags, answer) {
+                _cleanup_free_ char *next_hashed_domain = NULL;
+
+                r = nsec3_is_good(rr, zone_rr);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        continue;
+
+                r = nsec3_hashed_domain_format(rr->nsec3.next_hashed_name, rr->nsec3.next_hashed_name_size, zone, &next_hashed_domain);
+                if (r < 0)
+                        return r;
+
+                r = dns_name_between(dns_resource_key_name(rr->key), next_closer_domain, next_hashed_domain);
+                if (r < 0)
+                        return r;
+                if (r > 0) {
+                        if (rr->nsec3.flags & 1)
+                                optout = true;
+
+                        a = a && (flags & DNS_ANSWER_AUTHENTICATED);
+
+                        no_closer = true;
+                }
+
+                r = dns_name_equal(dns_resource_key_name(rr->key), wildcard_domain);
+                if (r < 0)
+                        return r;
+                if (r > 0) {
+                        a = a && (flags & DNS_ANSWER_AUTHENTICATED);
+
+                        wildcard_rr = rr;
+                }
+
+                r = dns_name_between(dns_resource_key_name(rr->key), wildcard_domain, next_hashed_domain);
+                if (r < 0)
+                        return r;
+                if (r > 0) {
+                        if (rr->nsec3.flags & 1)
+                                /* This only makes sense if we have a wildcard delegation, which is
+                                 * very unlikely, see RFC 4592, Section 4.2, but we cannot rely on
+                                 * this not happening, so hence cannot simply conclude NXDOMAIN as
+                                 * we would wish */
+                                optout = true;
+
+                        a = a && (flags & DNS_ANSWER_AUTHENTICATED);
+
+                        no_wildcard = true;
+                }
+        }
+
+        if (wildcard_rr && no_wildcard)
+                return -EBADMSG;
+
+        if (!no_closer) {
+                *result = DNSSEC_NSEC_NO_RR;
+                return 0;
+        }
+
+        if (wildcard_rr) {
+                /* A wildcard exists that matches our query. */
+                if (optout)
+                        /* This is not specified in any RFC to the best of my knowledge, but
+                         * if the next closer enclosure is covered by an opt-out NSEC3 RR
+                         * it means that we cannot prove that the source of synthesis is
+                         * correct, as there may be a closer match. */
+                        *result = DNSSEC_NSEC_OPTOUT;
+                else if (bitmap_isset(wildcard_rr->nsec3.types, key->type))
+                        *result = DNSSEC_NSEC_FOUND;
+                else if (bitmap_isset(wildcard_rr->nsec3.types, DNS_TYPE_CNAME))
+                        *result = DNSSEC_NSEC_CNAME;
+                else
+                        *result = DNSSEC_NSEC_NODATA;
+        } else {
+                if (optout)
+                        /* The RFC only specifies that we have to care for optout for NODATA for
+                         * DS records. However, children of an insecure opt-out delegation should
+                         * also be considered opt-out, rather than verified NXDOMAIN.
+                         * Note that we do not require a proof of wildcard non-existence if the
+                         * next closer domain is covered by an opt-out, as that would not provide
+                         * any additional information. */
+                        *result = DNSSEC_NSEC_OPTOUT;
+                else if (no_wildcard)
+                        *result = DNSSEC_NSEC_NXDOMAIN;
+                else {
+                        *result = DNSSEC_NSEC_NO_RR;
+
+                        return 0;
+                }
+        }
+
+        if (authenticated)
+                *authenticated = a;
+
+        if (ttl)
+                *ttl = enclosure_rr->ttl;
+
+        return 0;
+}
+
+static int dnssec_nsec_wildcard_equal(DnsResourceRecord *rr, const char *name) {
+        char label[DNS_LABEL_MAX];
+        const char *n;
+        int r;
+
+        assert(rr);
+        assert(rr->key->type == DNS_TYPE_NSEC);
+
+        /* Checks whether the specified RR has a name beginning in "*.", and if the rest is a suffix of our name */
+
+        if (rr->n_skip_labels_source != 1)
+                return 0;
+
+        n = dns_resource_key_name(rr->key);
+        r = dns_label_unescape(&n, label, sizeof(label));
+        if (r <= 0)
+                return r;
+        if (r != 1 || label[0] != '*')
+                return 0;
+
+        return dns_name_endswith(name, n);
+}
+
+static int dnssec_nsec_in_path(DnsResourceRecord *rr, const char *name) {
+        const char *nn, *common_suffix;
+        int r;
+
+        assert(rr);
+        assert(rr->key->type == DNS_TYPE_NSEC);
+
+        /* Checks whether the specified nsec RR indicates that name is an empty non-terminal (ENT)
+         *
+         * A couple of examples:
+         *
+         *      NSEC             bar →   waldo.foo.bar: indicates that foo.bar exists and is an ENT
+         *      NSEC   waldo.foo.bar → yyy.zzz.xoo.bar: indicates that xoo.bar and zzz.xoo.bar exist and are ENTs
+         *      NSEC yyy.zzz.xoo.bar →             bar: indicates pretty much nothing about ENTs
+         */
+
+        /* First, determine parent of next domain. */
+        nn = rr->nsec.next_domain_name;
+        r = dns_name_parent(&nn);
+        if (r <= 0)
+                return r;
+
+        /* If the name we just determined is not equal or child of the name we are interested in, then we can't say
+         * anything at all. */
+        r = dns_name_endswith(nn, name);
+        if (r <= 0)
+                return r;
+
+        /* If the name we are interested in is not a prefix of the common suffix of the NSEC RR's owner and next domain names, then we can't say anything either. */
+        r = dns_name_common_suffix(dns_resource_key_name(rr->key), rr->nsec.next_domain_name, &common_suffix);
+        if (r < 0)
+                return r;
+
+        return dns_name_endswith(name, common_suffix);
+}
+
+static int dnssec_nsec_from_parent_zone(DnsResourceRecord *rr, const char *name) {
+        int r;
+
+        assert(rr);
+        assert(rr->key->type == DNS_TYPE_NSEC);
+
+        /* Checks whether this NSEC originates to the parent zone or the child zone. */
+
+        r = dns_name_parent(&name);
+        if (r <= 0)
+                return r;
+
+        r = dns_name_equal(name, dns_resource_key_name(rr->key));
+        if (r <= 0)
+                return r;
+
+        /* DNAME, and NS without SOA is an indication for a delegation. */
+        if (bitmap_isset(rr->nsec.types, DNS_TYPE_DNAME))
+                return 1;
+
+        if (bitmap_isset(rr->nsec.types, DNS_TYPE_NS) && !bitmap_isset(rr->nsec.types, DNS_TYPE_SOA))
+                return 1;
+
+        return 0;
+}
+
+static int dnssec_nsec_covers(DnsResourceRecord *rr, const char *name) {
+        const char *common_suffix, *p;
+        int r;
+
+        assert(rr);
+        assert(rr->key->type == DNS_TYPE_NSEC);
+
+        /* Checks whether the "Next Closer" is witin the space covered by the specified RR. */
+
+        r = dns_name_common_suffix(dns_resource_key_name(rr->key), rr->nsec.next_domain_name, &common_suffix);
+        if (r < 0)
+                return r;
+
+        for (;;) {
+                p = name;
+                r = dns_name_parent(&name);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        return 0;
+
+                r = dns_name_equal(name, common_suffix);
+                if (r < 0)
+                        return r;
+                if (r > 0)
+                        break;
+        }
+
+        /* p is now the "Next Closer". */
+
+        return dns_name_between(dns_resource_key_name(rr->key), p, rr->nsec.next_domain_name);
+}
+
+static int dnssec_nsec_covers_wildcard(DnsResourceRecord *rr, const char *name) {
+        const char *common_suffix, *wc;
+        int r;
+
+        assert(rr);
+        assert(rr->key->type == DNS_TYPE_NSEC);
+
+        /* Checks whether the "Wildcard at the Closest Encloser" is within the space covered by the specified
+         * RR. Specifically, checks whether 'name' has the common suffix of the NSEC RR's owner and next names as
+         * suffix, and whether the NSEC covers the name generated by that suffix prepended with an asterisk label.
+         *
+         *     NSEC             bar →   waldo.foo.bar: indicates that *.bar and *.foo.bar do not exist
+         *     NSEC   waldo.foo.bar → yyy.zzz.xoo.bar: indicates that *.xoo.bar and *.zzz.xoo.bar do not exist (and more ...)
+         *     NSEC yyy.zzz.xoo.bar →             bar: indicates that a number of wildcards don#t exist either...
+         */
+
+        r = dns_name_common_suffix(dns_resource_key_name(rr->key), rr->nsec.next_domain_name, &common_suffix);
+        if (r < 0)
+                return r;
+
+        /* If the common suffix is not shared by the name we are interested in, it has nothing to say for us. */
+        r = dns_name_endswith(name, common_suffix);
+        if (r <= 0)
+                return r;
+
+        wc = strjoina("*.", common_suffix);
+        return dns_name_between(dns_resource_key_name(rr->key), wc, rr->nsec.next_domain_name);
+}
+
+int dnssec_nsec_test(DnsAnswer *answer, DnsResourceKey *key, DnssecNsecResult *result, bool *authenticated, uint32_t *ttl) {
+        bool have_nsec3 = false, covering_rr_authenticated = false, wildcard_rr_authenticated = false;
+        DnsResourceRecord *rr, *covering_rr = NULL, *wildcard_rr = NULL;
+        DnsAnswerFlags flags;
+        const char *name;
+        int r;
+
+        assert(key);
+        assert(result);
+
+        /* Look for any NSEC/NSEC3 RRs that say something about the specified key. */
+
+        name = dns_resource_key_name(key);
+
+        DNS_ANSWER_FOREACH_FLAGS(rr, flags, answer) {
+
+                if (rr->key->class != key->class)
+                        continue;
+
+                have_nsec3 = have_nsec3 || (rr->key->type == DNS_TYPE_NSEC3);
+
+                if (rr->key->type != DNS_TYPE_NSEC)
+                        continue;
+
+                /* The following checks only make sense for NSEC RRs that are not expanded from a wildcard */
+                r = dns_resource_record_is_synthetic(rr);
+                if (r < 0)
+                        return r;
+                if (r > 0)
+                        continue;
+
+                /* Check if this is a direct match. If so, we have encountered a NODATA case */
+                r = dns_name_equal(dns_resource_key_name(rr->key), name);
+                if (r < 0)
+                        return r;
+                if (r == 0) {
+                        /* If it's not a direct match, maybe it's a wild card match? */
+                        r = dnssec_nsec_wildcard_equal(rr, name);
+                        if (r < 0)
+                                return r;
+                }
+                if (r > 0) {
+                        if (key->type == DNS_TYPE_DS) {
+                                /* If we look for a DS RR and the server sent us the NSEC RR of the child zone
+                                 * we have a problem. For DS RRs we want the NSEC RR from the parent */
+                                if (bitmap_isset(rr->nsec.types, DNS_TYPE_SOA))
+                                        continue;
+                        } else {
+                                /* For all RR types, ensure that if NS is set SOA is set too, so that we know
+                                 * we got the child's NSEC. */
+                                if (bitmap_isset(rr->nsec.types, DNS_TYPE_NS) &&
+                                    !bitmap_isset(rr->nsec.types, DNS_TYPE_SOA))
+                                        continue;
+                        }
+
+                        if (bitmap_isset(rr->nsec.types, key->type))
+                                *result = DNSSEC_NSEC_FOUND;
+                        else if (bitmap_isset(rr->nsec.types, DNS_TYPE_CNAME))
+                                *result = DNSSEC_NSEC_CNAME;
+                        else
+                                *result = DNSSEC_NSEC_NODATA;
+
+                        if (authenticated)
+                                *authenticated = flags & DNS_ANSWER_AUTHENTICATED;
+                        if (ttl)
+                                *ttl = rr->ttl;
+
+                        return 0;
+                }
+
+                /* Check if the name we are looking for is an empty non-terminal within the owner or next name
+                 * of the NSEC RR. */
+                r = dnssec_nsec_in_path(rr, name);
+                if (r < 0)
+                        return r;
+                if (r > 0) {
+                        *result = DNSSEC_NSEC_NODATA;
+
+                        if (authenticated)
+                                *authenticated = flags & DNS_ANSWER_AUTHENTICATED;
+                        if (ttl)
+                                *ttl = rr->ttl;
+
+                        return 0;
+                }
+
+                /* The following two "covering" checks, are not useful if the NSEC is from the parent */
+                r = dnssec_nsec_from_parent_zone(rr, name);
+                if (r < 0)
+                        return r;
+                if (r > 0)
+                        continue;
+
+                /* Check if this NSEC RR proves the absence of an explicit RR under this name */
+                r = dnssec_nsec_covers(rr, name);
+                if (r < 0)
+                        return r;
+                if (r > 0 && (!covering_rr || !covering_rr_authenticated)) {
+                        covering_rr = rr;
+                        covering_rr_authenticated = flags & DNS_ANSWER_AUTHENTICATED;
+                }
+
+                /* Check if this NSEC RR proves the absence of a wildcard RR under this name */
+                r = dnssec_nsec_covers_wildcard(rr, name);
+                if (r < 0)
+                        return r;
+                if (r > 0 && (!wildcard_rr || !wildcard_rr_authenticated)) {
+                        wildcard_rr = rr;
+                        wildcard_rr_authenticated = flags & DNS_ANSWER_AUTHENTICATED;
+                }
+        }
+
+        if (covering_rr && wildcard_rr) {
+                /* If we could prove that neither the name itself, nor the wildcard at the closest encloser exists, we
+                 * proved the NXDOMAIN case. */
+                *result = DNSSEC_NSEC_NXDOMAIN;
+
+                if (authenticated)
+                        *authenticated = covering_rr_authenticated && wildcard_rr_authenticated;
+                if (ttl)
+                        *ttl = MIN(covering_rr->ttl, wildcard_rr->ttl);
+
+                return 0;
+        }
+
+        /* OK, this was not sufficient. Let's see if NSEC3 can help. */
+        if (have_nsec3)
+                return dnssec_test_nsec3(answer, key, result, authenticated, ttl);
+
+        /* No approproate NSEC RR found, report this. */
+        *result = DNSSEC_NSEC_NO_RR;
+        return 0;
+}
+
+static int dnssec_nsec_test_enclosed(DnsAnswer *answer, uint16_t type, const char *name, const char *zone, bool *authenticated) {
+        DnsResourceRecord *rr;
+        DnsAnswerFlags flags;
+        int r;
+
+        assert(name);
+        assert(zone);
+
+        /* Checks whether there's an NSEC/NSEC3 that proves that the specified 'name' is non-existing in the specified
+         * 'zone'. The 'zone' must be a suffix of the 'name'. */
+
+        DNS_ANSWER_FOREACH_FLAGS(rr, flags, answer) {
+                bool found = false;
+
+                if (rr->key->type != type && type != DNS_TYPE_ANY)
+                        continue;
+
+                switch (rr->key->type) {
+
+                case DNS_TYPE_NSEC:
+
+                        /* We only care for NSEC RRs from the indicated zone */
+                        r = dns_resource_record_is_signer(rr, zone);
+                        if (r < 0)
+                                return r;
+                        if (r == 0)
+                                continue;
+
+                        r = dns_name_between(dns_resource_key_name(rr->key), name, rr->nsec.next_domain_name);
+                        if (r < 0)
+                                return r;
+
+                        found = r > 0;
+                        break;
+
+                case DNS_TYPE_NSEC3: {
+                        _cleanup_free_ char *hashed_domain = NULL, *next_hashed_domain = NULL;
+
+                        /* We only care for NSEC3 RRs from the indicated zone */
+                        r = dns_resource_record_is_signer(rr, zone);
+                        if (r < 0)
+                                return r;
+                        if (r == 0)
+                                continue;
+
+                        r = nsec3_is_good(rr, NULL);
+                        if (r < 0)
+                                return r;
+                        if (r == 0)
+                                break;
+
+                        /* Format the domain we are testing with the NSEC3 RR's hash function */
+                        r = nsec3_hashed_domain_make(
+                                        rr,
+                                        name,
+                                        zone,
+                                        &hashed_domain);
+                        if (r < 0)
+                                return r;
+                        if ((size_t) r != rr->nsec3.next_hashed_name_size)
+                                break;
+
+                        /* Format the NSEC3's next hashed name as proper domain name */
+                        r = nsec3_hashed_domain_format(
+                                        rr->nsec3.next_hashed_name,
+                                        rr->nsec3.next_hashed_name_size,
+                                        zone,
+                                        &next_hashed_domain);
+                        if (r < 0)
+                                return r;
+
+                        r = dns_name_between(dns_resource_key_name(rr->key), hashed_domain, next_hashed_domain);
+                        if (r < 0)
+                                return r;
+
+                        found = r > 0;
+                        break;
+                }
+
+                default:
+                        continue;
+                }
+
+                if (found) {
+                        if (authenticated)
+                                *authenticated = flags & DNS_ANSWER_AUTHENTICATED;
+                        return 1;
+                }
+        }
+
+        return 0;
+}
+
+static int dnssec_test_positive_wildcard_nsec3(
+                DnsAnswer *answer,
+                const char *name,
+                const char *source,
+                const char *zone,
+                bool *authenticated) {
+
+        const char *next_closer = NULL;
+        int r;
+
+        /* Run a positive NSEC3 wildcard proof. Specifically:
+         *
+         * A proof that the "next closer" of the generating wildcard does not exist.
+         *
+         * Note a key difference between the NSEC3 and NSEC versions of the proof. NSEC RRs don't have to exist for
+         * empty non-transients. NSEC3 RRs however have to. This means it's sufficient to check if the next closer name
+         * exists for the NSEC3 RR and we are done.
+         *
+         * To prove that a.b.c.d.e.f is rightfully synthesized from a wildcard *.d.e.f all we have to check is that
+         * c.d.e.f does not exist. */
+
+        for (;;) {
+                next_closer = name;
+                r = dns_name_parent(&name);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        return 0;
+
+                r = dns_name_equal(name, source);
+                if (r < 0)
+                        return r;
+                if (r > 0)
+                        break;
+        }
+
+        return dnssec_nsec_test_enclosed(answer, DNS_TYPE_NSEC3, next_closer, zone, authenticated);
+}
+
+static int dnssec_test_positive_wildcard_nsec(
+                DnsAnswer *answer,
+                const char *name,
+                const char *source,
+                const char *zone,
+                bool *_authenticated) {
+
+        bool authenticated = true;
+        int r;
+
+        /* Run a positive NSEC wildcard proof. Specifically:
+         *
+         * A proof that there's neither a wildcard name nor a non-wildcard name that is a suffix of the name "name" and
+         * a prefix of the synthesizing source "source" in the zone "zone".
+         *
+         * See RFC 5155, Section 8.8 and RFC 4035, Section 5.3.4
+         *
+         * Note that if we want to prove that a.b.c.d.e.f is rightfully synthesized from a wildcard *.d.e.f, then we
+         * have to prove that none of the following exist:
+         *
+         *      1) a.b.c.d.e.f
+         *      2) *.b.c.d.e.f
+         *      3)   b.c.d.e.f
+         *      4)   *.c.d.e.f
+         *      5)     c.d.e.f
+         *
+         */
+
+        for (;;) {
+                _cleanup_free_ char *wc = NULL;
+                bool a = false;
+
+                /* Check if there's an NSEC or NSEC3 RR that proves that the mame we determined is really non-existing,
+                 * i.e between the owner name and the next name of an NSEC RR. */
+                r = dnssec_nsec_test_enclosed(answer, DNS_TYPE_NSEC, name, zone, &a);
+                if (r <= 0)
+                        return r;
+
+                authenticated = authenticated && a;
+
+                /* Strip one label off */
+                r = dns_name_parent(&name);
+                if (r <= 0)
+                        return r;
+
+                /* Did we reach the source of synthesis? */
+                r = dns_name_equal(name, source);
+                if (r < 0)
+                        return r;
+                if (r > 0) {
+                        /* Successful exit */
+                        *_authenticated = authenticated;
+                        return 1;
+                }
+
+                /* Safety check, that the source of synthesis is still our suffix */
+                r = dns_name_endswith(name, source);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        return -EBADMSG;
+
+                /* Replace the label we stripped off with an asterisk */
+                wc = strappend("*.", name);
+                if (!wc)
+                        return -ENOMEM;
+
+                /* And check if the proof holds for the asterisk name, too */
+                r = dnssec_nsec_test_enclosed(answer, DNS_TYPE_NSEC, wc, zone, &a);
+                if (r <= 0)
+                        return r;
+
+                authenticated = authenticated && a;
+                /* In the next iteration we'll check the non-asterisk-prefixed version */
+        }
+}
+
+int dnssec_test_positive_wildcard(
+                DnsAnswer *answer,
+                const char *name,
+                const char *source,
+                const char *zone,
+                bool *authenticated) {
+
+        int r;
+
+        assert(name);
+        assert(source);
+        assert(zone);
+        assert(authenticated);
+
+        r = dns_answer_contains_zone_nsec3(answer, zone);
+        if (r < 0)
+                return r;
+        if (r > 0)
+                return dnssec_test_positive_wildcard_nsec3(answer, name, source, zone, authenticated);
+        else
+                return dnssec_test_positive_wildcard_nsec(answer, name, source, zone, authenticated);
+}
+
+#else
+
+int dnssec_verify_rrset(
+                DnsAnswer *a,
+                const DnsResourceKey *key,
+                DnsResourceRecord *rrsig,
+                DnsResourceRecord *dnskey,
+                usec_t realtime,
+                DnssecResult *result) {
+
+        return -EOPNOTSUPP;
+}
+
+int dnssec_rrsig_match_dnskey(DnsResourceRecord *rrsig, DnsResourceRecord *dnskey, bool revoked_ok) {
+
+        return -EOPNOTSUPP;
+}
+
+int dnssec_key_match_rrsig(const DnsResourceKey *key, DnsResourceRecord *rrsig) {
+
+        return -EOPNOTSUPP;
+}
+
+int dnssec_verify_rrset_search(
+                DnsAnswer *a,
+                const DnsResourceKey *key,
+                DnsAnswer *validated_dnskeys,
+                usec_t realtime,
+                DnssecResult *result,
+                DnsResourceRecord **ret_rrsig) {
+
+        return -EOPNOTSUPP;
+}
+
+int dnssec_has_rrsig(DnsAnswer *a, const DnsResourceKey *key) {
+
+        return -EOPNOTSUPP;
+}
+
+int dnssec_verify_dnskey_by_ds(DnsResourceRecord *dnskey, DnsResourceRecord *ds, bool mask_revoke) {
+
+        return -EOPNOTSUPP;
+}
+
+int dnssec_verify_dnskey_by_ds_search(DnsResourceRecord *dnskey, DnsAnswer *validated_ds) {
+
+        return -EOPNOTSUPP;
+}
+
+int dnssec_nsec3_hash(DnsResourceRecord *nsec3, const char *name, void *ret) {
+
+        return -EOPNOTSUPP;
+}
+
+int dnssec_nsec_test(DnsAnswer *answer, DnsResourceKey *key, DnssecNsecResult *result, bool *authenticated, uint32_t *ttl) {
+
+        return -EOPNOTSUPP;
+}
+
+int dnssec_test_positive_wildcard(
+                DnsAnswer *answer,
+                const char *name,
+                const char *source,
+                const char *zone,
+                bool *authenticated) {
+
+        return -EOPNOTSUPP;
+}
+
+#endif
+
+static const char* const dnssec_result_table[_DNSSEC_RESULT_MAX] = {
+        [DNSSEC_VALIDATED] = "validated",
+        [DNSSEC_VALIDATED_WILDCARD] = "validated-wildcard",
+        [DNSSEC_INVALID] = "invalid",
+        [DNSSEC_SIGNATURE_EXPIRED] = "signature-expired",
+        [DNSSEC_UNSUPPORTED_ALGORITHM] = "unsupported-algorithm",
+        [DNSSEC_NO_SIGNATURE] = "no-signature",
+        [DNSSEC_MISSING_KEY] = "missing-key",
+        [DNSSEC_UNSIGNED] = "unsigned",
+        [DNSSEC_FAILED_AUXILIARY] = "failed-auxiliary",
+        [DNSSEC_NSEC_MISMATCH] = "nsec-mismatch",
+        [DNSSEC_INCOMPATIBLE_SERVER] = "incompatible-server",
+};
+DEFINE_STRING_TABLE_LOOKUP(dnssec_result, DnssecResult);
+
+static const char* const dnssec_verdict_table[_DNSSEC_VERDICT_MAX] = {
+        [DNSSEC_SECURE] = "secure",
+        [DNSSEC_INSECURE] = "insecure",
+        [DNSSEC_BOGUS] = "bogus",
+        [DNSSEC_INDETERMINATE] = "indeterminate",
+};
+DEFINE_STRING_TABLE_LOOKUP(dnssec_verdict, DnssecVerdict);
diff --git a/src/grp-resolve/libbasic-dns/src/resolved-dns-packet.c b/src/grp-resolve/libbasic-dns/src/resolved-dns-packet.c
new file mode 100644
index 0000000000..e142832211
--- /dev/null
+++ b/src/grp-resolve/libbasic-dns/src/resolved-dns-packet.c
@@ -0,0 +1,2300 @@
+/***
+  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/string-table.h"
+#include "systemd-basic/strv.h"
+#include "systemd-basic/unaligned.h"
+#include "systemd-basic/utf8.h"
+#include "systemd-basic/util.h"
+#include "systemd-shared/dns-domain.h"
+
+#define EDNS0_OPT_DO (1<<15)
+
+typedef struct DnsPacketRewinder {
+        DnsPacket *packet;
+        size_t saved_rindex;
+} DnsPacketRewinder;
+
+static void rewind_dns_packet(DnsPacketRewinder *rewinder) {
+        if (rewinder->packet)
+                dns_packet_rewind(rewinder->packet, rewinder->saved_rindex);
+}
+
+#define INIT_REWINDER(rewinder, p) do { rewinder.packet = p; rewinder.saved_rindex = p->rindex; } while (0)
+#define CANCEL_REWINDER(rewinder) do { rewinder.packet = NULL; } while (0)
+
+int dns_packet_new(DnsPacket **ret, DnsProtocol protocol, size_t mtu) {
+        DnsPacket *p;
+        size_t a;
+
+        assert(ret);
+
+        if (mtu <= UDP_PACKET_HEADER_SIZE)
+                a = DNS_PACKET_SIZE_START;
+        else
+                a = mtu - UDP_PACKET_HEADER_SIZE;
+
+        if (a < DNS_PACKET_HEADER_SIZE)
+                a = DNS_PACKET_HEADER_SIZE;
+
+        /* round up to next page size */
+        a = PAGE_ALIGN(ALIGN(sizeof(DnsPacket)) + a) - ALIGN(sizeof(DnsPacket));
+
+        /* make sure we never allocate more than useful */
+        if (a > DNS_PACKET_SIZE_MAX)
+                a = DNS_PACKET_SIZE_MAX;
+
+        p = malloc0(ALIGN(sizeof(DnsPacket)) + a);
+        if (!p)
+                return -ENOMEM;
+
+        p->size = p->rindex = DNS_PACKET_HEADER_SIZE;
+        p->allocated = a;
+        p->protocol = protocol;
+        p->opt_start = p->opt_size = (size_t) -1;
+        p->n_ref = 1;
+
+        *ret = p;
+
+        return 0;
+}
+
+void dns_packet_set_flags(DnsPacket *p, bool dnssec_checking_disabled, bool truncated) {
+
+        DnsPacketHeader *h;
+
+        assert(p);
+
+        h = DNS_PACKET_HEADER(p);
+
+        switch(p->protocol) {
+        case DNS_PROTOCOL_LLMNR:
+                assert(!truncated);
+
+                h->flags = htobe16(DNS_PACKET_MAKE_FLAGS(0 /* qr */,
+                                                         0 /* opcode */,
+                                                         0 /* c */,
+                                                         0 /* tc */,
+                                                         0 /* t */,
+                                                         0 /* ra */,
+                                                         0 /* ad */,
+                                                         0 /* cd */,
+                                                         0 /* rcode */));
+                break;
+
+        case DNS_PROTOCOL_MDNS:
+                h->flags = htobe16(DNS_PACKET_MAKE_FLAGS(0         /* qr */,
+                                                         0         /* opcode */,
+                                                         0         /* aa */,
+                                                         truncated /* tc */,
+                                                         0         /* rd (ask for recursion) */,
+                                                         0         /* ra */,
+                                                         0         /* ad */,
+                                                         0         /* cd */,
+                                                         0         /* rcode */));
+                break;
+
+        default:
+                assert(!truncated);
+
+                h->flags = htobe16(DNS_PACKET_MAKE_FLAGS(0 /* qr */,
+                                                         0 /* opcode */,
+                                                         0 /* aa */,
+                                                         0 /* tc */,
+                                                         1 /* rd (ask for recursion) */,
+                                                         0 /* ra */,
+                                                         0 /* ad */,
+                                                         dnssec_checking_disabled /* cd */,
+                                                         0 /* rcode */));
+        }
+}
+
+int dns_packet_new_query(DnsPacket **ret, DnsProtocol protocol, size_t mtu, bool dnssec_checking_disabled) {
+        DnsPacket *p;
+        int r;
+
+        assert(ret);
+
+        r = dns_packet_new(&p, protocol, mtu);
+        if (r < 0)
+                return r;
+
+        /* Always set the TC bit to 0 initially.
+         * If there are multiple packets later, we'll update the bit shortly before sending.
+         */
+        dns_packet_set_flags(p, dnssec_checking_disabled, false);
+
+        *ret = p;
+        return 0;
+}
+
+DnsPacket *dns_packet_ref(DnsPacket *p) {
+
+        if (!p)
+                return NULL;
+
+        assert(!p->on_stack);
+
+        assert(p->n_ref > 0);
+        p->n_ref++;
+        return p;
+}
+
+static void dns_packet_free(DnsPacket *p) {
+        char *s;
+
+        assert(p);
+
+        dns_question_unref(p->question);
+        dns_answer_unref(p->answer);
+        dns_resource_record_unref(p->opt);
+
+        while ((s = hashmap_steal_first_key(p->names)))
+                free(s);
+        hashmap_free(p->names);
+
+        free(p->_data);
+
+        if (!p->on_stack)
+                free(p);
+}
+
+DnsPacket *dns_packet_unref(DnsPacket *p) {
+        if (!p)
+                return NULL;
+
+        assert(p->n_ref > 0);
+
+        dns_packet_unref(p->more);
+
+        if (p->n_ref == 1)
+                dns_packet_free(p);
+        else
+                p->n_ref--;
+
+        return NULL;
+}
+
+int dns_packet_validate(DnsPacket *p) {
+        assert(p);
+
+        if (p->size < DNS_PACKET_HEADER_SIZE)
+                return -EBADMSG;
+
+        if (p->size > DNS_PACKET_SIZE_MAX)
+                return -EBADMSG;
+
+        return 1;
+}
+
+int dns_packet_validate_reply(DnsPacket *p) {
+        int r;
+
+        assert(p);
+
+        r = dns_packet_validate(p);
+        if (r < 0)
+                return r;
+
+        if (DNS_PACKET_QR(p) != 1)
+                return 0;
+
+        if (DNS_PACKET_OPCODE(p) != 0)
+                return -EBADMSG;
+
+        switch (p->protocol) {
+
+        case DNS_PROTOCOL_LLMNR:
+                /* RFC 4795, Section 2.1.1. says to discard all replies with QDCOUNT != 1 */
+                if (DNS_PACKET_QDCOUNT(p) != 1)
+                        return -EBADMSG;
+
+                break;
+
+        case DNS_PROTOCOL_MDNS:
+                /* RFC 6762, Section 18 */
+                if (DNS_PACKET_RCODE(p) != 0)
+                        return -EBADMSG;
+
+                break;
+
+        default:
+                break;
+        }
+
+        return 1;
+}
+
+int dns_packet_validate_query(DnsPacket *p) {
+        int r;
+
+        assert(p);
+
+        r = dns_packet_validate(p);
+        if (r < 0)
+                return r;
+
+        if (DNS_PACKET_QR(p) != 0)
+                return 0;
+
+        if (DNS_PACKET_OPCODE(p) != 0)
+                return -EBADMSG;
+
+        if (DNS_PACKET_TC(p))
+                return -EBADMSG;
+
+        switch (p->protocol) {
+
+        case DNS_PROTOCOL_LLMNR:
+        case DNS_PROTOCOL_DNS:
+                /* RFC 4795, Section 2.1.1. says to discard all queries with QDCOUNT != 1 */
+                if (DNS_PACKET_QDCOUNT(p) != 1)
+                        return -EBADMSG;
+
+                /* RFC 4795, Section 2.1.1. says to discard all queries with ANCOUNT != 0 */
+                if (DNS_PACKET_ANCOUNT(p) > 0)
+                        return -EBADMSG;
+
+                /* RFC 4795, Section 2.1.1. says to discard all queries with NSCOUNT != 0 */
+                if (DNS_PACKET_NSCOUNT(p) > 0)
+                        return -EBADMSG;
+
+                break;
+
+        case DNS_PROTOCOL_MDNS:
+                /* RFC 6762, Section 18 */
+                if (DNS_PACKET_AA(p)    != 0 ||
+                    DNS_PACKET_RD(p)    != 0 ||
+                    DNS_PACKET_RA(p)    != 0 ||
+                    DNS_PACKET_AD(p)    != 0 ||
+                    DNS_PACKET_CD(p)    != 0 ||
+                    DNS_PACKET_RCODE(p) != 0)
+                        return -EBADMSG;
+
+                break;
+
+        default:
+                break;
+        }
+
+        return 1;
+}
+
+static int dns_packet_extend(DnsPacket *p, size_t add, void **ret, size_t *start) {
+        assert(p);
+
+        if (p->size + add > p->allocated) {
+                size_t a;
+
+                a = PAGE_ALIGN((p->size + add) * 2);
+                if (a > DNS_PACKET_SIZE_MAX)
+                        a = DNS_PACKET_SIZE_MAX;
+
+                if (p->size + add > a)
+                        return -EMSGSIZE;
+
+                if (p->_data) {
+                        void *d;
+
+                        d = realloc(p->_data, a);
+                        if (!d)
+                                return -ENOMEM;
+
+                        p->_data = d;
+                } else {
+                        p->_data = malloc(a);
+                        if (!p->_data)
+                                return -ENOMEM;
+
+                        memcpy(p->_data, (uint8_t*) p + ALIGN(sizeof(DnsPacket)), p->size);
+                        memzero((uint8_t*) p->_data + p->size, a - p->size);
+                }
+
+                p->allocated = a;
+        }
+
+        if (start)
+                *start = p->size;
+
+        if (ret)
+                *ret = (uint8_t*) DNS_PACKET_DATA(p) + p->size;
+
+        p->size += add;
+        return 0;
+}
+
+void dns_packet_truncate(DnsPacket *p, size_t sz) {
+        Iterator i;
+        char *s;
+        void *n;
+
+        assert(p);
+
+        if (p->size <= sz)
+                return;
+
+        HASHMAP_FOREACH_KEY(n, s, p->names, i) {
+
+                if (PTR_TO_SIZE(n) < sz)
+                        continue;
+
+                hashmap_remove(p->names, s);
+                free(s);
+        }
+
+        p->size = sz;
+}
+
+int dns_packet_append_blob(DnsPacket *p, const void *d, size_t l, size_t *start) {
+        void *q;
+        int r;
+
+        assert(p);
+
+        r = dns_packet_extend(p, l, &q, start);
+        if (r < 0)
+                return r;
+
+        memcpy(q, d, l);
+        return 0;
+}
+
+int dns_packet_append_uint8(DnsPacket *p, uint8_t v, size_t *start) {
+        void *d;
+        int r;
+
+        assert(p);
+
+        r = dns_packet_extend(p, sizeof(uint8_t), &d, start);
+        if (r < 0)
+                return r;
+
+        ((uint8_t*) d)[0] = v;
+
+        return 0;
+}
+
+int dns_packet_append_uint16(DnsPacket *p, uint16_t v, size_t *start) {
+        void *d;
+        int r;
+
+        assert(p);
+
+        r = dns_packet_extend(p, sizeof(uint16_t), &d, start);
+        if (r < 0)
+                return r;
+
+        unaligned_write_be16(d, v);
+
+        return 0;
+}
+
+int dns_packet_append_uint32(DnsPacket *p, uint32_t v, size_t *start) {
+        void *d;
+        int r;
+
+        assert(p);
+
+        r = dns_packet_extend(p, sizeof(uint32_t), &d, start);
+        if (r < 0)
+                return r;
+
+        unaligned_write_be32(d, v);
+
+        return 0;
+}
+
+int dns_packet_append_string(DnsPacket *p, const char *s, size_t *start) {
+        assert(p);
+        assert(s);
+
+        return dns_packet_append_raw_string(p, s, strlen(s), start);
+}
+
+int dns_packet_append_raw_string(DnsPacket *p, const void *s, size_t size, size_t *start) {
+        void *d;
+        int r;
+
+        assert(p);
+        assert(s || size == 0);
+
+        if (size > 255)
+                return -E2BIG;
+
+        r = dns_packet_extend(p, 1 + size, &d, start);
+        if (r < 0)
+                return r;
+
+        ((uint8_t*) d)[0] = (uint8_t) size;
+
+        memcpy_safe(((uint8_t*) d) + 1, s, size);
+
+        return 0;
+}
+
+int dns_packet_append_label(DnsPacket *p, const char *d, size_t l, bool canonical_candidate, size_t *start) {
+        uint8_t *w;
+        int r;
+
+        /* Append a label to a packet. Optionally, does this in DNSSEC
+         * canonical form, if this label is marked as a candidate for
+         * it, and the canonical form logic is enabled for the
+         * packet */
+
+        assert(p);
+        assert(d);
+
+        if (l > DNS_LABEL_MAX)
+                return -E2BIG;
+
+        r = dns_packet_extend(p, 1 + l, (void**) &w, start);
+        if (r < 0)
+                return r;
+
+        *(w++) = (uint8_t) l;
+
+        if (p->canonical_form && canonical_candidate) {
+                size_t i;
+
+                /* Generate in canonical form, as defined by DNSSEC
+                 * RFC 4034, Section 6.2, i.e. all lower-case. */
+
+                for (i = 0; i < l; i++)
+                        w[i] = (uint8_t) ascii_tolower(d[i]);
+        } else
+                /* Otherwise, just copy the string unaltered. This is
+                 * essential for DNS-SD, where the casing of labels
+                 * matters and needs to be retained. */
+                memcpy(w, d, l);
+
+        return 0;
+}
+
+int dns_packet_append_name(
+                DnsPacket *p,
+                const char *name,
+                bool allow_compression,
+                bool canonical_candidate,
+                size_t *start) {
+
+        size_t saved_size;
+        int r;
+
+        assert(p);
+        assert(name);
+
+        if (p->refuse_compression)
+                allow_compression = false;
+
+        saved_size = p->size;
+
+        while (!dns_name_is_root(name)) {
+                const char *z = name;
+                char label[DNS_LABEL_MAX];
+                size_t n = 0;
+
+                if (allow_compression)
+                        n = PTR_TO_SIZE(hashmap_get(p->names, name));
+                if (n > 0) {
+                        assert(n < p->size);
+
+                        if (n < 0x4000) {
+                                r = dns_packet_append_uint16(p, 0xC000 | n, NULL);
+                                if (r < 0)
+                                        goto fail;
+
+                                goto done;
+                        }
+                }
+
+                r = dns_label_unescape(&name, label, sizeof(label));
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_label(p, label, r, canonical_candidate, &n);
+                if (r < 0)
+                        goto fail;
+
+                if (allow_compression) {
+                        _cleanup_free_ char *s = NULL;
+
+                        s = strdup(z);
+                        if (!s) {
+                                r = -ENOMEM;
+                                goto fail;
+                        }
+
+                        r = hashmap_ensure_allocated(&p->names, &dns_name_hash_ops);
+                        if (r < 0)
+                                goto fail;
+
+                        r = hashmap_put(p->names, s, SIZE_TO_PTR(n));
+                        if (r < 0)
+                                goto fail;
+
+                        s = NULL;
+                }
+        }
+
+        r = dns_packet_append_uint8(p, 0, NULL);
+        if (r < 0)
+                return r;
+
+done:
+        if (start)
+                *start = saved_size;
+
+        return 0;
+
+fail:
+        dns_packet_truncate(p, saved_size);
+        return r;
+}
+
+int dns_packet_append_key(DnsPacket *p, const DnsResourceKey *k, size_t *start) {
+        size_t saved_size;
+        int r;
+
+        assert(p);
+        assert(k);
+
+        saved_size = p->size;
+
+        r = dns_packet_append_name(p, dns_resource_key_name(k), true, true, NULL);
+        if (r < 0)
+                goto fail;
+
+        r = dns_packet_append_uint16(p, k->type, NULL);
+        if (r < 0)
+                goto fail;
+
+        r = dns_packet_append_uint16(p, k->class, NULL);
+        if (r < 0)
+                goto fail;
+
+        if (start)
+                *start = saved_size;
+
+        return 0;
+
+fail:
+        dns_packet_truncate(p, saved_size);
+        return r;
+}
+
+static int dns_packet_append_type_window(DnsPacket *p, uint8_t window, uint8_t length, const uint8_t *types, size_t *start) {
+        size_t saved_size;
+        int r;
+
+        assert(p);
+        assert(types);
+        assert(length > 0);
+
+        saved_size = p->size;
+
+        r = dns_packet_append_uint8(p, window, NULL);
+        if (r < 0)
+                goto fail;
+
+        r = dns_packet_append_uint8(p, length, NULL);
+        if (r < 0)
+                goto fail;
+
+        r = dns_packet_append_blob(p, types, length, NULL);
+        if (r < 0)
+                goto fail;
+
+        if (start)
+                *start = saved_size;
+
+        return 0;
+fail:
+        dns_packet_truncate(p, saved_size);
+        return r;
+}
+
+static int dns_packet_append_types(DnsPacket *p, Bitmap *types, size_t *start) {
+        Iterator i;
+        uint8_t window = 0;
+        uint8_t entry = 0;
+        uint8_t bitmaps[32] = {};
+        unsigned n;
+        size_t saved_size;
+        int r;
+
+        assert(p);
+
+        saved_size = p->size;
+
+        BITMAP_FOREACH(n, types, i) {
+                assert(n <= 0xffff);
+
+                if ((n >> 8) != window && bitmaps[entry / 8] != 0) {
+                        r = dns_packet_append_type_window(p, window, entry / 8 + 1, bitmaps, NULL);
+                        if (r < 0)
+                                goto fail;
+
+                        zero(bitmaps);
+                }
+
+                window = n >> 8;
+                entry = n & 255;
+
+                bitmaps[entry / 8] |= 1 << (7 - (entry % 8));
+        }
+
+        if (bitmaps[entry / 8] != 0) {
+                r = dns_packet_append_type_window(p, window, entry / 8 + 1, bitmaps, NULL);
+                if (r < 0)
+                        goto fail;
+        }
+
+        if (start)
+                *start = saved_size;
+
+        return 0;
+fail:
+        dns_packet_truncate(p, saved_size);
+        return r;
+}
+
+/* Append the OPT pseudo-RR described in RFC6891 */
+int dns_packet_append_opt(DnsPacket *p, uint16_t max_udp_size, bool edns0_do, int rcode, size_t *start) {
+        size_t saved_size;
+        int r;
+
+        assert(p);
+        /* we must never advertise supported packet size smaller than the legacy max */
+        assert(max_udp_size >= DNS_PACKET_UNICAST_SIZE_MAX);
+        assert(rcode >= 0);
+        assert(rcode <= _DNS_RCODE_MAX);
+
+        if (p->opt_start != (size_t) -1)
+                return -EBUSY;
+
+        assert(p->opt_size == (size_t) -1);
+
+        saved_size = p->size;
+
+        /* empty name */
+        r = dns_packet_append_uint8(p, 0, NULL);
+        if (r < 0)
+                return r;
+
+        /* type */
+        r = dns_packet_append_uint16(p, DNS_TYPE_OPT, NULL);
+        if (r < 0)
+                goto fail;
+
+        /* class: maximum udp packet that can be received */
+        r = dns_packet_append_uint16(p, max_udp_size, NULL);
+        if (r < 0)
+                goto fail;
+
+        /* extended RCODE and VERSION */
+        r = dns_packet_append_uint16(p, ((uint16_t) rcode & 0x0FF0) << 4, NULL);
+        if (r < 0)
+                goto fail;
+
+        /* flags: DNSSEC OK (DO), see RFC3225 */
+        r = dns_packet_append_uint16(p, edns0_do ? EDNS0_OPT_DO : 0, NULL);
+        if (r < 0)
+                goto fail;
+
+        /* RDLENGTH */
+        if (edns0_do && !DNS_PACKET_QR(p)) {
+                /* If DO is on and this is not a reply, also append RFC6975 Algorithm data */
+
+                static const uint8_t rfc6975[] = {
+
+                        0, 5, /* OPTION_CODE: DAU */
+                        0, 6, /* LIST_LENGTH */
+                        DNSSEC_ALGORITHM_RSASHA1,
+                        DNSSEC_ALGORITHM_RSASHA1_NSEC3_SHA1,
+                        DNSSEC_ALGORITHM_RSASHA256,
+                        DNSSEC_ALGORITHM_RSASHA512,
+                        DNSSEC_ALGORITHM_ECDSAP256SHA256,
+                        DNSSEC_ALGORITHM_ECDSAP384SHA384,
+
+                        0, 6, /* OPTION_CODE: DHU */
+                        0, 3, /* LIST_LENGTH */
+                        DNSSEC_DIGEST_SHA1,
+                        DNSSEC_DIGEST_SHA256,
+                        DNSSEC_DIGEST_SHA384,
+
+                        0, 7, /* OPTION_CODE: N3U */
+                        0, 1, /* LIST_LENGTH */
+                        NSEC3_ALGORITHM_SHA1,
+                };
+
+                r = dns_packet_append_uint16(p, sizeof(rfc6975), NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_blob(p, rfc6975, sizeof(rfc6975), NULL);
+        } else
+                r = dns_packet_append_uint16(p, 0, NULL);
+        if (r < 0)
+                goto fail;
+
+        DNS_PACKET_HEADER(p)->arcount = htobe16(DNS_PACKET_ARCOUNT(p) + 1);
+
+        p->opt_start = saved_size;
+        p->opt_size = p->size - saved_size;
+
+        if (start)
+                *start = saved_size;
+
+        return 0;
+
+fail:
+        dns_packet_truncate(p, saved_size);
+        return r;
+}
+
+int dns_packet_truncate_opt(DnsPacket *p) {
+        assert(p);
+
+        if (p->opt_start == (size_t) -1) {
+                assert(p->opt_size == (size_t) -1);
+                return 0;
+        }
+
+        assert(p->opt_size != (size_t) -1);
+        assert(DNS_PACKET_ARCOUNT(p) > 0);
+
+        if (p->opt_start + p->opt_size != p->size)
+                return -EBUSY;
+
+        dns_packet_truncate(p, p->opt_start);
+        DNS_PACKET_HEADER(p)->arcount = htobe16(DNS_PACKET_ARCOUNT(p) - 1);
+        p->opt_start = p->opt_size = (size_t) -1;
+
+        return 1;
+}
+
+int dns_packet_append_rr(DnsPacket *p, const DnsResourceRecord *rr, size_t *start, size_t *rdata_start) {
+
+        size_t saved_size, rdlength_offset, end, rdlength, rds;
+        int r;
+
+        assert(p);
+        assert(rr);
+
+        saved_size = p->size;
+
+        r = dns_packet_append_key(p, rr->key, NULL);
+        if (r < 0)
+                goto fail;
+
+        r = dns_packet_append_uint32(p, rr->ttl, NULL);
+        if (r < 0)
+                goto fail;
+
+        /* Initially we write 0 here */
+        r = dns_packet_append_uint16(p, 0, &rdlength_offset);
+        if (r < 0)
+                goto fail;
+
+        rds = p->size - saved_size;
+
+        switch (rr->unparseable ? _DNS_TYPE_INVALID : rr->key->type) {
+
+        case DNS_TYPE_SRV:
+                r = dns_packet_append_uint16(p, rr->srv.priority, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_uint16(p, rr->srv.weight, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_uint16(p, rr->srv.port, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_name(p, rr->srv.name, true, false, NULL);
+                break;
+
+        case DNS_TYPE_PTR:
+        case DNS_TYPE_NS:
+        case DNS_TYPE_CNAME:
+        case DNS_TYPE_DNAME:
+                r = dns_packet_append_name(p, rr->ptr.name, true, false, NULL);
+                break;
+
+        case DNS_TYPE_HINFO:
+                r = dns_packet_append_string(p, rr->hinfo.cpu, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_string(p, rr->hinfo.os, NULL);
+                break;
+
+        case DNS_TYPE_SPF: /* exactly the same as TXT */
+        case DNS_TYPE_TXT:
+
+                if (!rr->txt.items) {
+                        /* RFC 6763, section 6.1 suggests to generate
+                         * single empty string for an empty array. */
+
+                        r = dns_packet_append_raw_string(p, NULL, 0, NULL);
+                        if (r < 0)
+                                goto fail;
+                } else {
+                        DnsTxtItem *i;
+
+                        LIST_FOREACH(items, i, rr->txt.items) {
+                                r = dns_packet_append_raw_string(p, i->data, i->length, NULL);
+                                if (r < 0)
+                                        goto fail;
+                        }
+                }
+
+                r = 0;
+                break;
+
+        case DNS_TYPE_A:
+                r = dns_packet_append_blob(p, &rr->a.in_addr, sizeof(struct in_addr), NULL);
+                break;
+
+        case DNS_TYPE_AAAA:
+                r = dns_packet_append_blob(p, &rr->aaaa.in6_addr, sizeof(struct in6_addr), NULL);
+                break;
+
+        case DNS_TYPE_SOA:
+                r = dns_packet_append_name(p, rr->soa.mname, true, false, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_name(p, rr->soa.rname, true, false, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_uint32(p, rr->soa.serial, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_uint32(p, rr->soa.refresh, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_uint32(p, rr->soa.retry, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_uint32(p, rr->soa.expire, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_uint32(p, rr->soa.minimum, NULL);
+                break;
+
+        case DNS_TYPE_MX:
+                r = dns_packet_append_uint16(p, rr->mx.priority, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_name(p, rr->mx.exchange, true, false, NULL);
+                break;
+
+        case DNS_TYPE_LOC:
+                r = dns_packet_append_uint8(p, rr->loc.version, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_uint8(p, rr->loc.size, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_uint8(p, rr->loc.horiz_pre, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_uint8(p, rr->loc.vert_pre, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_uint32(p, rr->loc.latitude, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_uint32(p, rr->loc.longitude, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_uint32(p, rr->loc.altitude, NULL);
+                break;
+
+        case DNS_TYPE_DS:
+                r = dns_packet_append_uint16(p, rr->ds.key_tag, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_uint8(p, rr->ds.algorithm, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_uint8(p, rr->ds.digest_type, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_blob(p, rr->ds.digest, rr->ds.digest_size, NULL);
+                break;
+
+        case DNS_TYPE_SSHFP:
+                r = dns_packet_append_uint8(p, rr->sshfp.algorithm, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_uint8(p, rr->sshfp.fptype, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_blob(p, rr->sshfp.fingerprint, rr->sshfp.fingerprint_size, NULL);
+                break;
+
+        case DNS_TYPE_DNSKEY:
+                r = dns_packet_append_uint16(p, rr->dnskey.flags, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_uint8(p, rr->dnskey.protocol, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_uint8(p, rr->dnskey.algorithm, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_blob(p, rr->dnskey.key, rr->dnskey.key_size, NULL);
+                break;
+
+        case DNS_TYPE_RRSIG:
+                r = dns_packet_append_uint16(p, rr->rrsig.type_covered, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_uint8(p, rr->rrsig.algorithm, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_uint8(p, rr->rrsig.labels, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_uint32(p, rr->rrsig.original_ttl, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_uint32(p, rr->rrsig.expiration, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_uint32(p, rr->rrsig.inception, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_uint16(p, rr->rrsig.key_tag, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_name(p, rr->rrsig.signer, false, true, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_blob(p, rr->rrsig.signature, rr->rrsig.signature_size, NULL);
+                break;
+
+        case DNS_TYPE_NSEC:
+                r = dns_packet_append_name(p, rr->nsec.next_domain_name, false, false, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_types(p, rr->nsec.types, NULL);
+                if (r < 0)
+                        goto fail;
+
+                break;
+
+        case DNS_TYPE_NSEC3:
+                r = dns_packet_append_uint8(p, rr->nsec3.algorithm, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_uint8(p, rr->nsec3.flags, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_uint16(p, rr->nsec3.iterations, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_uint8(p, rr->nsec3.salt_size, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_blob(p, rr->nsec3.salt, rr->nsec3.salt_size, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_uint8(p, rr->nsec3.next_hashed_name_size, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_blob(p, rr->nsec3.next_hashed_name, rr->nsec3.next_hashed_name_size, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_types(p, rr->nsec3.types, NULL);
+                if (r < 0)
+                        goto fail;
+
+                break;
+
+        case DNS_TYPE_TLSA:
+                r = dns_packet_append_uint8(p, rr->tlsa.cert_usage, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_uint8(p, rr->tlsa.selector, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_uint8(p, rr->tlsa.matching_type, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_blob(p, rr->tlsa.data, rr->tlsa.data_size, NULL);
+                break;
+
+        case DNS_TYPE_CAA:
+                r = dns_packet_append_uint8(p, rr->caa.flags, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_string(p, rr->caa.tag, NULL);
+                if (r < 0)
+                        goto fail;
+
+                r = dns_packet_append_blob(p, rr->caa.value, rr->caa.value_size, NULL);
+                break;
+
+        case DNS_TYPE_OPT:
+        case DNS_TYPE_OPENPGPKEY:
+        case _DNS_TYPE_INVALID: /* unparseable */
+        default:
+
+                r = dns_packet_append_blob(p, rr->generic.data, rr->generic.data_size, NULL);
+                break;
+        }
+        if (r < 0)
+                goto fail;
+
+        /* Let's calculate the actual data size and update the field */
+        rdlength = p->size - rdlength_offset - sizeof(uint16_t);
+        if (rdlength > 0xFFFF) {
+                r = -ENOSPC;
+                goto fail;
+        }
+
+        end = p->size;
+        p->size = rdlength_offset;
+        r = dns_packet_append_uint16(p, rdlength, NULL);
+        if (r < 0)
+                goto fail;
+        p->size = end;
+
+        if (start)
+                *start = saved_size;
+
+        if (rdata_start)
+                *rdata_start = rds;
+
+        return 0;
+
+fail:
+        dns_packet_truncate(p, saved_size);
+        return r;
+}
+
+int dns_packet_append_question(DnsPacket *p, DnsQuestion *q) {
+        DnsResourceKey *key;
+        int r;
+
+        assert(p);
+
+        DNS_QUESTION_FOREACH(key, q) {
+                r = dns_packet_append_key(p, key, NULL);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+int dns_packet_append_answer(DnsPacket *p, DnsAnswer *a) {
+        DnsResourceRecord *rr;
+        int r;
+
+        assert(p);
+
+        DNS_ANSWER_FOREACH(rr, a) {
+                r = dns_packet_append_rr(p, rr, NULL, NULL);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+int dns_packet_read(DnsPacket *p, size_t sz, const void **ret, size_t *start) {
+        assert(p);
+
+        if (p->rindex + sz > p->size)
+                return -EMSGSIZE;
+
+        if (ret)
+                *ret = (uint8_t*) DNS_PACKET_DATA(p) + p->rindex;
+
+        if (start)
+                *start = p->rindex;
+
+        p->rindex += sz;
+        return 0;
+}
+
+void dns_packet_rewind(DnsPacket *p, size_t idx) {
+        assert(p);
+        assert(idx <= p->size);
+        assert(idx >= DNS_PACKET_HEADER_SIZE);
+
+        p->rindex = idx;
+}
+
+int dns_packet_read_blob(DnsPacket *p, void *d, size_t sz, size_t *start) {
+        const void *q;
+        int r;
+
+        assert(p);
+        assert(d);
+
+        r = dns_packet_read(p, sz, &q, start);
+        if (r < 0)
+                return r;
+
+        memcpy(d, q, sz);
+        return 0;
+}
+
+static int dns_packet_read_memdup(
+                DnsPacket *p, size_t size,
+                void **ret, size_t *ret_size,
+                size_t *ret_start) {
+
+        const void *src;
+        size_t start;
+        int r;
+
+        assert(p);
+        assert(ret);
+
+        r = dns_packet_read(p, size, &src, &start);
+        if (r < 0)
+                return r;
+
+        if (size <= 0)
+                *ret = NULL;
+        else {
+                void *copy;
+
+                copy = memdup(src, size);
+                if (!copy)
+                        return -ENOMEM;
+
+                *ret = copy;
+        }
+
+        if (ret_size)
+                *ret_size = size;
+        if (ret_start)
+                *ret_start = start;
+
+        return 0;
+}
+
+int dns_packet_read_uint8(DnsPacket *p, uint8_t *ret, size_t *start) {
+        const void *d;
+        int r;
+
+        assert(p);
+
+        r = dns_packet_read(p, sizeof(uint8_t), &d, start);
+        if (r < 0)
+                return r;
+
+        *ret = ((uint8_t*) d)[0];
+        return 0;
+}
+
+int dns_packet_read_uint16(DnsPacket *p, uint16_t *ret, size_t *start) {
+        const void *d;
+        int r;
+
+        assert(p);
+
+        r = dns_packet_read(p, sizeof(uint16_t), &d, start);
+        if (r < 0)
+                return r;
+
+        *ret = unaligned_read_be16(d);
+
+        return 0;
+}
+
+int dns_packet_read_uint32(DnsPacket *p, uint32_t *ret, size_t *start) {
+        const void *d;
+        int r;
+
+        assert(p);
+
+        r = dns_packet_read(p, sizeof(uint32_t), &d, start);
+        if (r < 0)
+                return r;
+
+        *ret = unaligned_read_be32(d);
+
+        return 0;
+}
+
+int dns_packet_read_string(DnsPacket *p, char **ret, size_t *start) {
+        _cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder;
+        const void *d;
+        char *t;
+        uint8_t c;
+        int r;
+
+        assert(p);
+        INIT_REWINDER(rewinder, p);
+
+        r = dns_packet_read_uint8(p, &c, NULL);
+        if (r < 0)
+                return r;
+
+        r = dns_packet_read(p, c, &d, NULL);
+        if (r < 0)
+                return r;
+
+        if (memchr(d, 0, c))
+                return -EBADMSG;
+
+        t = strndup(d, c);
+        if (!t)
+                return -ENOMEM;
+
+        if (!utf8_is_valid(t)) {
+                free(t);
+                return -EBADMSG;
+        }
+
+        *ret = t;
+
+        if (start)
+                *start = rewinder.saved_rindex;
+        CANCEL_REWINDER(rewinder);
+
+        return 0;
+}
+
+int dns_packet_read_raw_string(DnsPacket *p, const void **ret, size_t *size, size_t *start) {
+        _cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder;
+        uint8_t c;
+        int r;
+
+        assert(p);
+        INIT_REWINDER(rewinder, p);
+
+        r = dns_packet_read_uint8(p, &c, NULL);
+        if (r < 0)
+                return r;
+
+        r = dns_packet_read(p, c, ret, NULL);
+        if (r < 0)
+                return r;
+
+        if (size)
+                *size = c;
+        if (start)
+                *start = rewinder.saved_rindex;
+        CANCEL_REWINDER(rewinder);
+
+        return 0;
+}
+
+int dns_packet_read_name(
+                DnsPacket *p,
+                char **_ret,
+                bool allow_compression,
+                size_t *start) {
+
+        _cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder;
+        size_t after_rindex = 0, jump_barrier;
+        _cleanup_free_ char *ret = NULL;
+        size_t n = 0, allocated = 0;
+        bool first = true;
+        int r;
+
+        assert(p);
+        assert(_ret);
+        INIT_REWINDER(rewinder, p);
+        jump_barrier = p->rindex;
+
+        if (p->refuse_compression)
+                allow_compression = false;
+
+        for (;;) {
+                uint8_t c, d;
+
+                r = dns_packet_read_uint8(p, &c, NULL);
+                if (r < 0)
+                        return r;
+
+                if (c == 0)
+                        /* End of name */
+                        break;
+                else if (c <= 63) {
+                        const char *label;
+
+                        /* Literal label */
+                        r = dns_packet_read(p, c, (const void**) &label, NULL);
+                        if (r < 0)
+                                return r;
+
+                        if (!GREEDY_REALLOC(ret, allocated, n + !first + DNS_LABEL_ESCAPED_MAX))
+                                return -ENOMEM;
+
+                        if (first)
+                                first = false;
+                        else
+                                ret[n++] = '.';
+
+                        r = dns_label_escape(label, c, ret + n, DNS_LABEL_ESCAPED_MAX);
+                        if (r < 0)
+                                return r;
+
+                        n += r;
+                        continue;
+                } else if (allow_compression && (c & 0xc0) == 0xc0) {
+                        uint16_t ptr;
+
+                        /* Pointer */
+                        r = dns_packet_read_uint8(p, &d, NULL);
+                        if (r < 0)
+                                return r;
+
+                        ptr = (uint16_t) (c & ~0xc0) << 8 | (uint16_t) d;
+                        if (ptr < DNS_PACKET_HEADER_SIZE || ptr >= jump_barrier)
+                                return -EBADMSG;
+
+                        if (after_rindex == 0)
+                                after_rindex = p->rindex;
+
+                        /* Jumps are limited to a "prior occurrence" (RFC-1035 4.1.4) */
+                        jump_barrier = ptr;
+                        p->rindex = ptr;
+                } else
+                        return -EBADMSG;
+        }
+
+        if (!GREEDY_REALLOC(ret, allocated, n + 1))
+                return -ENOMEM;
+
+        ret[n] = 0;
+
+        if (after_rindex != 0)
+                p->rindex= after_rindex;
+
+        *_ret = ret;
+        ret = NULL;
+
+        if (start)
+                *start = rewinder.saved_rindex;
+        CANCEL_REWINDER(rewinder);
+
+        return 0;
+}
+
+static int dns_packet_read_type_window(DnsPacket *p, Bitmap **types, size_t *start) {
+        uint8_t window;
+        uint8_t length;
+        const uint8_t *bitmap;
+        uint8_t bit = 0;
+        unsigned i;
+        bool found = false;
+        _cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder;
+        int r;
+
+        assert(p);
+        assert(types);
+        INIT_REWINDER(rewinder, p);
+
+        r = bitmap_ensure_allocated(types);
+        if (r < 0)
+                return r;
+
+        r = dns_packet_read_uint8(p, &window, NULL);
+        if (r < 0)
+                return r;
+
+        r = dns_packet_read_uint8(p, &length, NULL);
+        if (r < 0)
+                return r;
+
+        if (length == 0 || length > 32)
+                return -EBADMSG;
+
+        r = dns_packet_read(p, length, (const void **)&bitmap, NULL);
+        if (r < 0)
+                return r;
+
+        for (i = 0; i < length; i++) {
+                uint8_t bitmask = 1 << 7;
+
+                if (!bitmap[i]) {
+                        found = false;
+                        bit += 8;
+                        continue;
+                }
+
+                found = true;
+
+                while (bitmask) {
+                        if (bitmap[i] & bitmask) {
+                                uint16_t n;
+
+                                n = (uint16_t) window << 8 | (uint16_t) bit;
+
+                                /* Ignore pseudo-types. see RFC4034 section 4.1.2 */
+                                if (dns_type_is_pseudo(n))
+                                        continue;
+
+                                r = bitmap_set(*types, n);
+                                if (r < 0)
+                                        return r;
+                        }
+
+                        bit++;
+                        bitmask >>= 1;
+                }
+        }
+
+        if (!found)
+                return -EBADMSG;
+
+        if (start)
+                *start = rewinder.saved_rindex;
+        CANCEL_REWINDER(rewinder);
+
+        return 0;
+}
+
+static int dns_packet_read_type_windows(DnsPacket *p, Bitmap **types, size_t size, size_t *start) {
+        _cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder;
+        int r;
+
+        INIT_REWINDER(rewinder, p);
+
+        while (p->rindex < rewinder.saved_rindex + size) {
+                r = dns_packet_read_type_window(p, types, NULL);
+                if (r < 0)
+                        return r;
+
+                /* don't read past end of current RR */
+                if (p->rindex > rewinder.saved_rindex + size)
+                        return -EBADMSG;
+        }
+
+        if (p->rindex != rewinder.saved_rindex + size)
+                return -EBADMSG;
+
+        if (start)
+                *start = rewinder.saved_rindex;
+        CANCEL_REWINDER(rewinder);
+
+        return 0;
+}
+
+int dns_packet_read_key(DnsPacket *p, DnsResourceKey **ret, bool *ret_cache_flush, size_t *start) {
+        _cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder;
+        _cleanup_free_ char *name = NULL;
+        bool cache_flush = false;
+        uint16_t class, type;
+        DnsResourceKey *key;
+        int r;
+
+        assert(p);
+        assert(ret);
+        INIT_REWINDER(rewinder, p);
+
+        r = dns_packet_read_name(p, &name, true, NULL);
+        if (r < 0)
+                return r;
+
+        r = dns_packet_read_uint16(p, &type, NULL);
+        if (r < 0)
+                return r;
+
+        r = dns_packet_read_uint16(p, &class, NULL);
+        if (r < 0)
+                return r;
+
+        if (p->protocol == DNS_PROTOCOL_MDNS) {
+                /* See RFC6762, Section 10.2 */
+
+                if (type != DNS_TYPE_OPT && (class & MDNS_RR_CACHE_FLUSH)) {
+                        class &= ~MDNS_RR_CACHE_FLUSH;
+                        cache_flush = true;
+                }
+        }
+
+        key = dns_resource_key_new_consume(class, type, name);
+        if (!key)
+                return -ENOMEM;
+
+        name = NULL;
+        *ret = key;
+
+        if (ret_cache_flush)
+                *ret_cache_flush = cache_flush;
+        if (start)
+                *start = rewinder.saved_rindex;
+        CANCEL_REWINDER(rewinder);
+
+        return 0;
+}
+
+static bool loc_size_ok(uint8_t size) {
+        uint8_t m = size >> 4, e = size & 0xF;
+
+        return m <= 9 && e <= 9 && (m > 0 || e == 0);
+}
+
+int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, bool *ret_cache_flush, size_t *start) {
+        _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
+        _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL;
+        _cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder;
+        size_t offset;
+        uint16_t rdlength;
+        bool cache_flush;
+        int r;
+
+        assert(p);
+        assert(ret);
+
+        INIT_REWINDER(rewinder, p);
+
+        r = dns_packet_read_key(p, &key, &cache_flush, NULL);
+        if (r < 0)
+                return r;
+
+        if (!dns_class_is_valid_rr(key->class) || !dns_type_is_valid_rr(key->type))
+                return -EBADMSG;
+
+        rr = dns_resource_record_new(key);
+        if (!rr)
+                return -ENOMEM;
+
+        r = dns_packet_read_uint32(p, &rr->ttl, NULL);
+        if (r < 0)
+                return r;
+
+        /* RFC 2181, Section 8, suggests to
+         * treat a TTL with the MSB set as a zero TTL. */
+        if (rr->ttl & UINT32_C(0x80000000))
+                rr->ttl = 0;
+
+        r = dns_packet_read_uint16(p, &rdlength, NULL);
+        if (r < 0)
+                return r;
+
+        if (p->rindex + rdlength > p->size)
+                return -EBADMSG;
+
+        offset = p->rindex;
+
+        switch (rr->key->type) {
+
+        case DNS_TYPE_SRV:
+                r = dns_packet_read_uint16(p, &rr->srv.priority, NULL);
+                if (r < 0)
+                        return r;
+                r = dns_packet_read_uint16(p, &rr->srv.weight, NULL);
+                if (r < 0)
+                        return r;
+                r = dns_packet_read_uint16(p, &rr->srv.port, NULL);
+                if (r < 0)
+                        return r;
+                r = dns_packet_read_name(p, &rr->srv.name, true, NULL);
+                break;
+
+        case DNS_TYPE_PTR:
+        case DNS_TYPE_NS:
+        case DNS_TYPE_CNAME:
+        case DNS_TYPE_DNAME:
+                r = dns_packet_read_name(p, &rr->ptr.name, true, NULL);
+                break;
+
+        case DNS_TYPE_HINFO:
+                r = dns_packet_read_string(p, &rr->hinfo.cpu, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_string(p, &rr->hinfo.os, NULL);
+                break;
+
+        case DNS_TYPE_SPF: /* exactly the same as TXT */
+        case DNS_TYPE_TXT:
+                if (rdlength <= 0) {
+                        DnsTxtItem *i;
+                        /* RFC 6763, section 6.1 suggests to treat
+                         * empty TXT RRs as equivalent to a TXT record
+                         * with a single empty string. */
+
+                        i = malloc0(offsetof(DnsTxtItem, data) + 1); /* for safety reasons we add an extra NUL byte */
+                        if (!i)
+                                return -ENOMEM;
+
+                        rr->txt.items = i;
+                } else {
+                        DnsTxtItem *last = NULL;
+
+                        while (p->rindex < offset + rdlength) {
+                                DnsTxtItem *i;
+                                const void *data;
+                                size_t sz;
+
+                                r = dns_packet_read_raw_string(p, &data, &sz, NULL);
+                                if (r < 0)
+                                        return r;
+
+                                i = malloc0(offsetof(DnsTxtItem, data) + sz + 1); /* extra NUL byte at the end */
+                                if (!i)
+                                        return -ENOMEM;
+
+                                memcpy(i->data, data, sz);
+                                i->length = sz;
+
+                                LIST_INSERT_AFTER(items, rr->txt.items, last, i);
+                                last = i;
+                        }
+                }
+
+                r = 0;
+                break;
+
+        case DNS_TYPE_A:
+                r = dns_packet_read_blob(p, &rr->a.in_addr, sizeof(struct in_addr), NULL);
+                break;
+
+        case DNS_TYPE_AAAA:
+                r = dns_packet_read_blob(p, &rr->aaaa.in6_addr, sizeof(struct in6_addr), NULL);
+                break;
+
+        case DNS_TYPE_SOA:
+                r = dns_packet_read_name(p, &rr->soa.mname, true, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_name(p, &rr->soa.rname, true, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_uint32(p, &rr->soa.serial, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_uint32(p, &rr->soa.refresh, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_uint32(p, &rr->soa.retry, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_uint32(p, &rr->soa.expire, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_uint32(p, &rr->soa.minimum, NULL);
+                break;
+
+        case DNS_TYPE_MX:
+                r = dns_packet_read_uint16(p, &rr->mx.priority, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_name(p, &rr->mx.exchange, true, NULL);
+                break;
+
+        case DNS_TYPE_LOC: {
+                uint8_t t;
+                size_t pos;
+
+                r = dns_packet_read_uint8(p, &t, &pos);
+                if (r < 0)
+                        return r;
+
+                if (t == 0) {
+                        rr->loc.version = t;
+
+                        r = dns_packet_read_uint8(p, &rr->loc.size, NULL);
+                        if (r < 0)
+                                return r;
+
+                        if (!loc_size_ok(rr->loc.size))
+                                return -EBADMSG;
+
+                        r = dns_packet_read_uint8(p, &rr->loc.horiz_pre, NULL);
+                        if (r < 0)
+                                return r;
+
+                        if (!loc_size_ok(rr->loc.horiz_pre))
+                                return -EBADMSG;
+
+                        r = dns_packet_read_uint8(p, &rr->loc.vert_pre, NULL);
+                        if (r < 0)
+                                return r;
+
+                        if (!loc_size_ok(rr->loc.vert_pre))
+                                return -EBADMSG;
+
+                        r = dns_packet_read_uint32(p, &rr->loc.latitude, NULL);
+                        if (r < 0)
+                                return r;
+
+                        r = dns_packet_read_uint32(p, &rr->loc.longitude, NULL);
+                        if (r < 0)
+                                return r;
+
+                        r = dns_packet_read_uint32(p, &rr->loc.altitude, NULL);
+                        if (r < 0)
+                                return r;
+
+                        break;
+                } else {
+                        dns_packet_rewind(p, pos);
+                        rr->unparseable = true;
+                        goto unparseable;
+                }
+        }
+
+        case DNS_TYPE_DS:
+                r = dns_packet_read_uint16(p, &rr->ds.key_tag, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_uint8(p, &rr->ds.algorithm, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_uint8(p, &rr->ds.digest_type, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_memdup(p, rdlength - 4,
+                                           &rr->ds.digest, &rr->ds.digest_size,
+                                           NULL);
+                if (r < 0)
+                        return r;
+
+                if (rr->ds.digest_size <= 0)
+                        /* the accepted size depends on the algorithm, but for now
+                           just ensure that the value is greater than zero */
+                        return -EBADMSG;
+
+                break;
+
+        case DNS_TYPE_SSHFP:
+                r = dns_packet_read_uint8(p, &rr->sshfp.algorithm, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_uint8(p, &rr->sshfp.fptype, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_memdup(p, rdlength - 2,
+                                           &rr->sshfp.fingerprint, &rr->sshfp.fingerprint_size,
+                                           NULL);
+
+                if (rr->sshfp.fingerprint_size <= 0)
+                        /* the accepted size depends on the algorithm, but for now
+                           just ensure that the value is greater than zero */
+                        return -EBADMSG;
+
+                break;
+
+        case DNS_TYPE_DNSKEY:
+                r = dns_packet_read_uint16(p, &rr->dnskey.flags, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_uint8(p, &rr->dnskey.protocol, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_uint8(p, &rr->dnskey.algorithm, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_memdup(p, rdlength - 4,
+                                           &rr->dnskey.key, &rr->dnskey.key_size,
+                                           NULL);
+
+                if (rr->dnskey.key_size <= 0)
+                        /* the accepted size depends on the algorithm, but for now
+                           just ensure that the value is greater than zero */
+                        return -EBADMSG;
+
+                break;
+
+        case DNS_TYPE_RRSIG:
+                r = dns_packet_read_uint16(p, &rr->rrsig.type_covered, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_uint8(p, &rr->rrsig.algorithm, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_uint8(p, &rr->rrsig.labels, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_uint32(p, &rr->rrsig.original_ttl, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_uint32(p, &rr->rrsig.expiration, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_uint32(p, &rr->rrsig.inception, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_uint16(p, &rr->rrsig.key_tag, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_name(p, &rr->rrsig.signer, false, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_memdup(p, offset + rdlength - p->rindex,
+                                           &rr->rrsig.signature, &rr->rrsig.signature_size,
+                                           NULL);
+
+                if (rr->rrsig.signature_size <= 0)
+                        /* the accepted size depends on the algorithm, but for now
+                           just ensure that the value is greater than zero */
+                        return -EBADMSG;
+
+                break;
+
+        case DNS_TYPE_NSEC: {
+
+                /*
+                 * RFC6762, section 18.14 explictly states mDNS should use name compression.
+                 * This contradicts RFC3845, section 2.1.1
+                 */
+
+                bool allow_compressed = p->protocol == DNS_PROTOCOL_MDNS;
+
+                r = dns_packet_read_name(p, &rr->nsec.next_domain_name, allow_compressed, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_type_windows(p, &rr->nsec.types, offset + rdlength - p->rindex, NULL);
+
+                /* We accept empty NSEC bitmaps. The bit indicating the presence of the NSEC record itself
+                 * is redundant and in e.g., RFC4956 this fact is used to define a use for NSEC records
+                 * without the NSEC bit set. */
+
+                break;
+        }
+        case DNS_TYPE_NSEC3: {
+                uint8_t size;
+
+                r = dns_packet_read_uint8(p, &rr->nsec3.algorithm, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_uint8(p, &rr->nsec3.flags, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_uint16(p, &rr->nsec3.iterations, NULL);
+                if (r < 0)
+                        return r;
+
+                /* this may be zero */
+                r = dns_packet_read_uint8(p, &size, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_memdup(p, size, &rr->nsec3.salt, &rr->nsec3.salt_size, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_uint8(p, &size, NULL);
+                if (r < 0)
+                        return r;
+
+                if (size <= 0)
+                        return -EBADMSG;
+
+                r = dns_packet_read_memdup(p, size,
+                                           &rr->nsec3.next_hashed_name, &rr->nsec3.next_hashed_name_size,
+                                           NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_type_windows(p, &rr->nsec3.types, offset + rdlength - p->rindex, NULL);
+
+                /* empty non-terminals can have NSEC3 records, so empty bitmaps are allowed */
+
+                break;
+        }
+
+        case DNS_TYPE_TLSA:
+                r = dns_packet_read_uint8(p, &rr->tlsa.cert_usage, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_uint8(p, &rr->tlsa.selector, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_uint8(p, &rr->tlsa.matching_type, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_memdup(p, rdlength - 3,
+                                           &rr->tlsa.data, &rr->tlsa.data_size,
+                                           NULL);
+
+                if (rr->tlsa.data_size <= 0)
+                        /* the accepted size depends on the algorithm, but for now
+                           just ensure that the value is greater than zero */
+                        return -EBADMSG;
+
+                break;
+
+        case DNS_TYPE_CAA:
+                r = dns_packet_read_uint8(p, &rr->caa.flags, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_string(p, &rr->caa.tag, NULL);
+                if (r < 0)
+                        return r;
+
+                r = dns_packet_read_memdup(p,
+                                           rdlength + offset - p->rindex,
+                                           &rr->caa.value, &rr->caa.value_size, NULL);
+
+                break;
+
+        case DNS_TYPE_OPT: /* we only care about the header of OPT for now. */
+        case DNS_TYPE_OPENPGPKEY:
+        default:
+        unparseable:
+                r = dns_packet_read_memdup(p, rdlength, &rr->generic.data, &rr->generic.data_size, NULL);
+
+                break;
+        }
+        if (r < 0)
+                return r;
+        if (p->rindex != offset + rdlength)
+                return -EBADMSG;
+
+        *ret = rr;
+        rr = NULL;
+
+        if (ret_cache_flush)
+                *ret_cache_flush = cache_flush;
+        if (start)
+                *start = rewinder.saved_rindex;
+        CANCEL_REWINDER(rewinder);
+
+        return 0;
+}
+
+static bool opt_is_good(DnsResourceRecord *rr, bool *rfc6975) {
+        const uint8_t* p;
+        bool found_dau_dhu_n3u = false;
+        size_t l;
+
+        /* Checks whether the specified OPT RR is well-formed and whether it contains RFC6975 data (which is not OK in
+         * a reply). */
+
+        assert(rr);
+        assert(rr->key->type == DNS_TYPE_OPT);
+
+        /* Check that the version is 0 */
+        if (((rr->ttl >> 16) & UINT32_C(0xFF)) != 0) {
+                *rfc6975 = false;
+                return true; /* if it's not version 0, it's OK, but we will ignore the OPT field contents */
+        }
+
+        p = rr->opt.data;
+        l = rr->opt.data_size;
+        while (l > 0) {
+                uint16_t option_code, option_length;
+
+                /* At least four bytes for OPTION-CODE and OPTION-LENGTH are required */
+                if (l < 4U)
+                        return false;
+
+                option_code = unaligned_read_be16(p);
+                option_length = unaligned_read_be16(p + 2);
+
+                if (l < option_length + 4U)
+                        return false;
+
+                /* RFC 6975 DAU, DHU or N3U fields found. */
+                if (IN_SET(option_code, 5, 6, 7))
+                        found_dau_dhu_n3u = true;
+
+                p += option_length + 4U;
+                l -= option_length + 4U;
+        }
+
+        *rfc6975 = found_dau_dhu_n3u;
+        return true;
+}
+
+int dns_packet_extract(DnsPacket *p) {
+        _cleanup_(dns_question_unrefp) DnsQuestion *question = NULL;
+        _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
+        _cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder = {};
+        unsigned n, i;
+        int r;
+
+        if (p->extracted)
+                return 0;
+
+        INIT_REWINDER(rewinder, p);
+        dns_packet_rewind(p, DNS_PACKET_HEADER_SIZE);
+
+        n = DNS_PACKET_QDCOUNT(p);
+        if (n > 0) {
+                question = dns_question_new(n);
+                if (!question)
+                        return -ENOMEM;
+
+                for (i = 0; i < n; i++) {
+                        _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL;
+                        bool cache_flush;
+
+                        r = dns_packet_read_key(p, &key, &cache_flush, NULL);
+                        if (r < 0)
+                                return r;
+
+                        if (cache_flush)
+                                return -EBADMSG;
+
+                        if (!dns_type_is_valid_query(key->type))
+                                return -EBADMSG;
+
+                        r = dns_question_add(question, key);
+                        if (r < 0)
+                                return r;
+                }
+        }
+
+        n = DNS_PACKET_RRCOUNT(p);
+        if (n > 0) {
+                _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *previous = NULL;
+                bool bad_opt = false;
+
+                answer = dns_answer_new(n);
+                if (!answer)
+                        return -ENOMEM;
+
+                for (i = 0; i < n; i++) {
+                        _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
+                        bool cache_flush;
+
+                        r = dns_packet_read_rr(p, &rr, &cache_flush, NULL);
+                        if (r < 0)
+                                return r;
+
+                        /* Try to reduce memory usage a bit */
+                        if (previous)
+                                dns_resource_key_reduce(&rr->key, &previous->key);
+
+                        if (rr->key->type == DNS_TYPE_OPT) {
+                                bool has_rfc6975;
+
+                                if (p->opt || bad_opt) {
+                                        /* Multiple OPT RRs? if so, let's ignore all, because there's something wrong
+                                         * with the server, and if one is valid we wouldn't know which one. */
+                                        log_debug("Multiple OPT RRs detected, ignoring all.");
+                                        bad_opt = true;
+                                        continue;
+                                }
+
+                                if (!dns_name_is_root(dns_resource_key_name(rr->key))) {
+                                        /* If the OPT RR is not owned by the root domain, then it is bad, let's ignore
+                                         * it. */
+                                        log_debug("OPT RR is not owned by root domain, ignoring.");
+                                        bad_opt = true;
+                                        continue;
+                                }
+
+                                if (i < DNS_PACKET_ANCOUNT(p) + DNS_PACKET_NSCOUNT(p)) {
+                                        /* OPT RR is in the wrong section? Some Belkin routers do this. This is a hint
+                                         * the EDNS implementation is borked, like the Belkin one is, hence ignore
+                                         * it. */
+                                        log_debug("OPT RR in wrong section, ignoring.");
+                                        bad_opt = true;
+                                        continue;
+                                }
+
+                                if (!opt_is_good(rr, &has_rfc6975)) {
+                                        log_debug("Malformed OPT RR, ignoring.");
+                                        bad_opt = true;
+                                        continue;
+                                }
+
+                                if (DNS_PACKET_QR(p)) {
+                                        /* Additional checks for responses */
+
+                                        if (!DNS_RESOURCE_RECORD_OPT_VERSION_SUPPORTED(rr)) {
+                                                /* If this is a reply and we don't know the EDNS version then something
+                                                 * is weird... */
+                                                log_debug("EDNS version newer that our request, bad server.");
+                                                return -EBADMSG;
+                                        }
+
+                                        if (has_rfc6975) {
+                                                /* If the OPT RR contains RFC6975 algorithm data, then this is indication that
+                                                 * the server just copied the OPT it got from us (which contained that data)
+                                                 * back into the reply. If so, then it doesn't properly support EDNS, as
+                                                 * RFC6975 makes it very clear that the algorithm data should only be contained
+                                                 * in questions, never in replies. Crappy Belkin routers copy the OPT data for
+                                                 * example, hence let's detect this so that we downgrade early. */
+                                                log_debug("OPT RR contained RFC6975 data, ignoring.");
+                                                bad_opt = true;
+                                                continue;
+                                        }
+                                }
+
+                                p->opt = dns_resource_record_ref(rr);
+                        } else {
+
+                                /* According to RFC 4795, section 2.9. only the RRs from the Answer section shall be
+                                 * cached. Hence mark only those RRs as cacheable by default, but not the ones from the
+                                 * Additional or Authority sections. */
+
+                                r = dns_answer_add(answer, rr, p->ifindex,
+                                                   (i < DNS_PACKET_ANCOUNT(p) ? DNS_ANSWER_CACHEABLE : 0) |
+                                                   (p->protocol == DNS_PROTOCOL_MDNS && !cache_flush ? DNS_ANSWER_SHARED_OWNER : 0));
+                                if (r < 0)
+                                        return r;
+                        }
+
+                        /* Remember this RR, so that we potentically can merge it's ->key object with the next RR. Note
+                         * that we only do this if we actually decided to keep the RR around. */
+                        dns_resource_record_unref(previous);
+                        previous = dns_resource_record_ref(rr);
+                }
+
+                if (bad_opt)
+                        p->opt = dns_resource_record_unref(p->opt);
+        }
+
+        p->question = question;
+        question = NULL;
+
+        p->answer = answer;
+        answer = NULL;
+
+        p->extracted = true;
+
+        /* no CANCEL, always rewind */
+        return 0;
+}
+
+int dns_packet_is_reply_for(DnsPacket *p, const DnsResourceKey *key) {
+        int r;
+
+        assert(p);
+        assert(key);
+
+        /* Checks if the specified packet is a reply for the specified
+         * key and the specified key is the only one in the question
+         * section. */
+
+        if (DNS_PACKET_QR(p) != 1)
+                return 0;
+
+        /* Let's unpack the packet, if that hasn't happened yet. */
+        r = dns_packet_extract(p);
+        if (r < 0)
+                return r;
+
+        if (p->question->n_keys != 1)
+                return 0;
+
+        return dns_resource_key_equal(p->question->keys[0], key);
+}
+
+static const char* const dns_rcode_table[_DNS_RCODE_MAX_DEFINED] = {
+        [DNS_RCODE_SUCCESS] = "SUCCESS",
+        [DNS_RCODE_FORMERR] = "FORMERR",
+        [DNS_RCODE_SERVFAIL] = "SERVFAIL",
+        [DNS_RCODE_NXDOMAIN] = "NXDOMAIN",
+        [DNS_RCODE_NOTIMP] = "NOTIMP",
+        [DNS_RCODE_REFUSED] = "REFUSED",
+        [DNS_RCODE_YXDOMAIN] = "YXDOMAIN",
+        [DNS_RCODE_YXRRSET] = "YRRSET",
+        [DNS_RCODE_NXRRSET] = "NXRRSET",
+        [DNS_RCODE_NOTAUTH] = "NOTAUTH",
+        [DNS_RCODE_NOTZONE] = "NOTZONE",
+        [DNS_RCODE_BADVERS] = "BADVERS",
+        [DNS_RCODE_BADKEY] = "BADKEY",
+        [DNS_RCODE_BADTIME] = "BADTIME",
+        [DNS_RCODE_BADMODE] = "BADMODE",
+        [DNS_RCODE_BADNAME] = "BADNAME",
+        [DNS_RCODE_BADALG] = "BADALG",
+        [DNS_RCODE_BADTRUNC] = "BADTRUNC",
+};
+DEFINE_STRING_TABLE_LOOKUP(dns_rcode, int);
+
+static const char* const dns_protocol_table[_DNS_PROTOCOL_MAX] = {
+        [DNS_PROTOCOL_DNS] = "dns",
+        [DNS_PROTOCOL_MDNS] = "mdns",
+        [DNS_PROTOCOL_LLMNR] = "llmnr",
+};
+DEFINE_STRING_TABLE_LOOKUP(dns_protocol, DnsProtocol);
diff --git a/src/grp-resolve/libbasic-dns/src/resolved-dns-question.c b/src/grp-resolve/libbasic-dns/src/resolved-dns-question.c
new file mode 100644
index 0000000000..672ef6207d
--- /dev/null
+++ b/src/grp-resolve/libbasic-dns/src/resolved-dns-question.c
@@ -0,0 +1,468 @@
+/***
+  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 "basic-dns/resolved-dns-question.h"
+#include "systemd-basic/alloc-util.h"
+#include "systemd-shared/dns-domain.h"
+
+DnsQuestion *dns_question_new(unsigned n) {
+        DnsQuestion *q;
+
+        assert(n > 0);
+
+        q = malloc0(offsetof(DnsQuestion, keys) + sizeof(DnsResourceKey*) * n);
+        if (!q)
+                return NULL;
+
+        q->n_ref = 1;
+        q->n_allocated = n;
+
+        return q;
+}
+
+DnsQuestion *dns_question_ref(DnsQuestion *q) {
+        if (!q)
+                return NULL;
+
+        assert(q->n_ref > 0);
+        q->n_ref++;
+        return q;
+}
+
+DnsQuestion *dns_question_unref(DnsQuestion *q) {
+        if (!q)
+                return NULL;
+
+        assert(q->n_ref > 0);
+
+        if (q->n_ref == 1) {
+                unsigned i;
+
+                for (i = 0; i < q->n_keys; i++)
+                        dns_resource_key_unref(q->keys[i]);
+                free(q);
+        } else
+                q->n_ref--;
+
+        return  NULL;
+}
+
+int dns_question_add(DnsQuestion *q, DnsResourceKey *key) {
+        unsigned i;
+        int r;
+
+        assert(key);
+
+        if (!q)
+                return -ENOSPC;
+
+        for (i = 0; i < q->n_keys; i++) {
+                r = dns_resource_key_equal(q->keys[i], key);
+                if (r < 0)
+                        return r;
+                if (r > 0)
+                        return 0;
+        }
+
+        if (q->n_keys >= q->n_allocated)
+                return -ENOSPC;
+
+        q->keys[q->n_keys++] = dns_resource_key_ref(key);
+        return 0;
+}
+
+int dns_question_matches_rr(DnsQuestion *q, DnsResourceRecord *rr, const char *search_domain) {
+        unsigned i;
+        int r;
+
+        assert(rr);
+
+        if (!q)
+                return 0;
+
+        for (i = 0; i < q->n_keys; i++) {
+                r = dns_resource_key_match_rr(q->keys[i], rr, search_domain);
+                if (r != 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+int dns_question_matches_cname_or_dname(DnsQuestion *q, DnsResourceRecord *rr, const char *search_domain) {
+        unsigned i;
+        int r;
+
+        assert(rr);
+
+        if (!q)
+                return 0;
+
+        if (!IN_SET(rr->key->type, DNS_TYPE_CNAME, DNS_TYPE_DNAME))
+                return 0;
+
+        for (i = 0; i < q->n_keys; i++) {
+                /* For a {C,D}NAME record we can never find a matching {C,D}NAME record */
+                if (!dns_type_may_redirect(q->keys[i]->type))
+                        return 0;
+
+                r = dns_resource_key_match_cname_or_dname(q->keys[i], rr->key, search_domain);
+                if (r != 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+int dns_question_is_valid_for_query(DnsQuestion *q) {
+        const char *name;
+        unsigned i;
+        int r;
+
+        if (!q)
+                return 0;
+
+        if (q->n_keys <= 0)
+                return 0;
+
+        if (q->n_keys > 65535)
+                return 0;
+
+        name = dns_resource_key_name(q->keys[0]);
+        if (!name)
+                return 0;
+
+        /* Check that all keys in this question bear the same name */
+        for (i = 0; i < q->n_keys; i++) {
+                assert(q->keys[i]);
+
+                if (i > 0) {
+                        r = dns_name_equal(dns_resource_key_name(q->keys[i]), name);
+                        if (r <= 0)
+                                return r;
+                }
+
+                if (!dns_type_is_valid_query(q->keys[i]->type))
+                        return 0;
+        }
+
+        return 1;
+}
+
+int dns_question_contains(DnsQuestion *a, const DnsResourceKey *k) {
+        unsigned j;
+        int r;
+
+        assert(k);
+
+        if (!a)
+                return 0;
+
+        for (j = 0; j < a->n_keys; j++) {
+                r = dns_resource_key_equal(a->keys[j], k);
+                if (r != 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+int dns_question_is_equal(DnsQuestion *a, DnsQuestion *b) {
+        unsigned j;
+        int r;
+
+        if (a == b)
+                return 1;
+
+        if (!a)
+                return !b || b->n_keys == 0;
+        if (!b)
+                return a->n_keys == 0;
+
+        /* Checks if all keys in a are also contained b, and vice versa */
+
+        for (j = 0; j < a->n_keys; j++) {
+                r = dns_question_contains(b, a->keys[j]);
+                if (r <= 0)
+                        return r;
+        }
+
+        for (j = 0; j < b->n_keys; j++) {
+                r = dns_question_contains(a, b->keys[j]);
+                if (r <= 0)
+                        return r;
+        }
+
+        return 1;
+}
+
+int dns_question_cname_redirect(DnsQuestion *q, const DnsResourceRecord *cname, DnsQuestion **ret) {
+        _cleanup_(dns_question_unrefp) DnsQuestion *n = NULL;
+        DnsResourceKey *key;
+        bool same = true;
+        int r;
+
+        assert(cname);
+        assert(ret);
+        assert(IN_SET(cname->key->type, DNS_TYPE_CNAME, DNS_TYPE_DNAME));
+
+        if (dns_question_size(q) <= 0) {
+                *ret = NULL;
+                return 0;
+        }
+
+        DNS_QUESTION_FOREACH(key, q) {
+                _cleanup_free_ char *destination = NULL;
+                const char *d;
+
+                if (cname->key->type == DNS_TYPE_CNAME)
+                        d = cname->cname.name;
+                else {
+                        r = dns_name_change_suffix(dns_resource_key_name(key), dns_resource_key_name(cname->key), cname->dname.name, &destination);
+                        if (r < 0)
+                                return r;
+                        if (r == 0)
+                                continue;
+
+                        d = destination;
+                }
+
+                r = dns_name_equal(dns_resource_key_name(key), d);
+                if (r < 0)
+                        return r;
+
+                if (r == 0) {
+                        same = false;
+                        break;
+                }
+        }
+
+        /* Fully the same, indicate we didn't do a thing */
+        if (same) {
+                *ret = NULL;
+                return 0;
+        }
+
+        n = dns_question_new(q->n_keys);
+        if (!n)
+                return -ENOMEM;
+
+        /* Create a new question, and patch in the new name */
+        DNS_QUESTION_FOREACH(key, q) {
+                _cleanup_(dns_resource_key_unrefp) DnsResourceKey *k = NULL;
+
+                k = dns_resource_key_new_redirect(key, cname);
+                if (!k)
+                        return -ENOMEM;
+
+                r = dns_question_add(n, k);
+                if (r < 0)
+                        return r;
+        }
+
+        *ret = n;
+        n = NULL;
+
+        return 1;
+}
+
+const char *dns_question_first_name(DnsQuestion *q) {
+
+        if (!q)
+                return NULL;
+
+        if (q->n_keys < 1)
+                return NULL;
+
+        return dns_resource_key_name(q->keys[0]);
+}
+
+int dns_question_new_address(DnsQuestion **ret, int family, const char *name, bool convert_idna) {
+        _cleanup_(dns_question_unrefp) DnsQuestion *q = NULL;
+        _cleanup_free_ char *buf = NULL;
+        int r;
+
+        assert(ret);
+        assert(name);
+
+        if (!IN_SET(family, AF_INET, AF_INET6, AF_UNSPEC))
+                return -EAFNOSUPPORT;
+
+        if (convert_idna) {
+                r = dns_name_apply_idna(name, &buf);
+                if (r < 0)
+                        return r;
+
+                name = buf;
+        }
+
+        q = dns_question_new(family == AF_UNSPEC ? 2 : 1);
+        if (!q)
+                return -ENOMEM;
+
+        if (family != AF_INET6) {
+                _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL;
+
+                key = dns_resource_key_new(DNS_CLASS_IN, DNS_TYPE_A, name);
+                if (!key)
+                        return -ENOMEM;
+
+                r = dns_question_add(q, key);
+                if (r < 0)
+                        return r;
+        }
+
+        if (family != AF_INET) {
+                _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL;
+
+                key = dns_resource_key_new(DNS_CLASS_IN, DNS_TYPE_AAAA, name);
+                if (!key)
+                        return -ENOMEM;
+
+                r = dns_question_add(q, key);
+                if (r < 0)
+                        return r;
+        }
+
+        *ret = q;
+        q = NULL;
+
+        return 0;
+}
+
+int dns_question_new_reverse(DnsQuestion **ret, int family, const union in_addr_union *a) {
+        _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL;
+        _cleanup_(dns_question_unrefp) DnsQuestion *q = NULL;
+        _cleanup_free_ char *reverse = NULL;
+        int r;
+
+        assert(ret);
+        assert(a);
+
+        if (!IN_SET(family, AF_INET, AF_INET6, AF_UNSPEC))
+                return -EAFNOSUPPORT;
+
+        r = dns_name_reverse(family, a, &reverse);
+        if (r < 0)
+                return r;
+
+        q = dns_question_new(1);
+        if (!q)
+                return -ENOMEM;
+
+        key = dns_resource_key_new_consume(DNS_CLASS_IN, DNS_TYPE_PTR, reverse);
+        if (!key)
+                return -ENOMEM;
+
+        reverse = NULL;
+
+        r = dns_question_add(q, key);
+        if (r < 0)
+                return r;
+
+        *ret = q;
+        q = NULL;
+
+        return 0;
+}
+
+int dns_question_new_service(
+                DnsQuestion **ret,
+                const char *service,
+                const char *type,
+                const char *domain,
+                bool with_txt,
+                bool convert_idna) {
+
+        _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL;
+        _cleanup_(dns_question_unrefp) DnsQuestion *q = NULL;
+        _cleanup_free_ char *buf = NULL, *joined = NULL;
+        const char *name;
+        int r;
+
+        assert(ret);
+
+        /* We support three modes of invocation:
+         *
+         * 1. Only a domain is specified, in which case we assume a properly encoded SRV RR name, including service
+         *    type and possibly a service name. If specified in this way we assume it's already IDNA converted if
+         *    that's necessary.
+         *
+         * 2. Both service type and a domain specified, in which case a normal SRV RR is assumed, without a DNS-SD
+         *    style prefix. In this case we'll IDNA convert the domain, if that's requested.
+         *
+         * 3. All three of service name, type and domain are specified, in which case a DNS-SD service is put
+         *    together. The service name is never IDNA converted, and the domain is if requested.
+         *
+         * It's not supported to specify a service name without a type, or no domain name.
+         */
+
+        if (!domain)
+                return -EINVAL;
+
+        if (type) {
+                if (convert_idna) {
+                        r = dns_name_apply_idna(domain, &buf);
+                        if (r < 0)
+                                return r;
+
+                        domain = buf;
+                }
+
+                r = dns_service_join(service, type, domain, &joined);
+                if (r < 0)
+                        return r;
+
+                name = joined;
+        } else {
+                if (service)
+                        return -EINVAL;
+
+                name = domain;
+        }
+
+        q = dns_question_new(1 + with_txt);
+        if (!q)
+                return -ENOMEM;
+
+        key = dns_resource_key_new(DNS_CLASS_IN, DNS_TYPE_SRV, name);
+        if (!key)
+                return -ENOMEM;
+
+        r = dns_question_add(q, key);
+        if (r < 0)
+                return r;
+
+        if (with_txt) {
+                dns_resource_key_unref(key);
+                key = dns_resource_key_new(DNS_CLASS_IN, DNS_TYPE_TXT, name);
+                if (!key)
+                        return -ENOMEM;
+
+                r = dns_question_add(q, key);
+                if (r < 0)
+                        return r;
+        }
+
+        *ret = q;
+        q = NULL;
+
+        return 0;
+}
diff --git a/src/grp-resolve/libbasic-dns/src/resolved-dns-rr.c b/src/grp-resolve/libbasic-dns/src/resolved-dns-rr.c
new file mode 100644
index 0000000000..35d389b802
--- /dev/null
+++ b/src/grp-resolve/libbasic-dns/src/resolved-dns-rr.c
@@ -0,0 +1,1839 @@
+/***
+  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 <math.h>
+
+#include "basic-dns/dns-type.h"
+#include "basic-dns/resolved-dns-dnssec.h"
+#include "basic-dns/resolved-dns-packet.h"
+#include "basic-dns/resolved-dns-rr.h"
+#include "systemd-basic/alloc-util.h"
+#include "systemd-basic/escape.h"
+#include "systemd-basic/hexdecoct.h"
+#include "systemd-basic/string-table.h"
+#include "systemd-basic/string-util.h"
+#include "systemd-basic/strv.h"
+#include "systemd-basic/terminal-util.h"
+#include "systemd-shared/dns-domain.h"
+
+DnsResourceKey* dns_resource_key_new(uint16_t class, uint16_t type, const char *name) {
+        DnsResourceKey *k;
+        size_t l;
+
+        assert(name);
+
+        l = strlen(name);
+        k = malloc0(sizeof(DnsResourceKey) + l + 1);
+        if (!k)
+                return NULL;
+
+        k->n_ref = 1;
+        k->class = class;
+        k->type = type;
+
+        strcpy((char*) k + sizeof(DnsResourceKey), name);
+
+        return k;
+}
+
+DnsResourceKey* dns_resource_key_new_redirect(const DnsResourceKey *key, const DnsResourceRecord *cname) {
+        int r;
+
+        assert(key);
+        assert(cname);
+
+        assert(IN_SET(cname->key->type, DNS_TYPE_CNAME, DNS_TYPE_DNAME));
+
+        if (cname->key->type == DNS_TYPE_CNAME)
+                return dns_resource_key_new(key->class, key->type, cname->cname.name);
+        else {
+                DnsResourceKey *k;
+                char *destination = NULL;
+
+                r = dns_name_change_suffix(dns_resource_key_name(key), dns_resource_key_name(cname->key), cname->dname.name, &destination);
+                if (r < 0)
+                        return NULL;
+                if (r == 0)
+                        return dns_resource_key_ref((DnsResourceKey*) key);
+
+                k = dns_resource_key_new_consume(key->class, key->type, destination);
+                if (!k) {
+                        free(destination);
+                        return NULL;
+                }
+
+                return k;
+        }
+}
+
+int dns_resource_key_new_append_suffix(DnsResourceKey **ret, DnsResourceKey *key, char *name) {
+        DnsResourceKey *new_key;
+        char *joined;
+        int r;
+
+        assert(ret);
+        assert(key);
+        assert(name);
+
+        if (dns_name_is_root(name)) {
+                *ret = dns_resource_key_ref(key);
+                return 0;
+        }
+
+        r = dns_name_concat(dns_resource_key_name(key), name, &joined);
+        if (r < 0)
+                return r;
+
+        new_key = dns_resource_key_new_consume(key->class, key->type, joined);
+        if (!new_key) {
+                free(joined);
+                return -ENOMEM;
+        }
+
+        *ret = new_key;
+        return 0;
+}
+
+DnsResourceKey* dns_resource_key_new_consume(uint16_t class, uint16_t type, char *name) {
+        DnsResourceKey *k;
+
+        assert(name);
+
+        k = new0(DnsResourceKey, 1);
+        if (!k)
+                return NULL;
+
+        k->n_ref = 1;
+        k->class = class;
+        k->type = type;
+        k->_name = name;
+
+        return k;
+}
+
+DnsResourceKey* dns_resource_key_ref(DnsResourceKey *k) {
+
+        if (!k)
+                return NULL;
+
+        /* Static/const keys created with DNS_RESOURCE_KEY_CONST will
+         * set this to -1, they should not be reffed/unreffed */
+        assert(k->n_ref != (unsigned) -1);
+
+        assert(k->n_ref > 0);
+        k->n_ref++;
+
+        return k;
+}
+
+DnsResourceKey* dns_resource_key_unref(DnsResourceKey *k) {
+        if (!k)
+                return NULL;
+
+        assert(k->n_ref != (unsigned) -1);
+        assert(k->n_ref > 0);
+
+        if (k->n_ref == 1) {
+                free(k->_name);
+                free(k);
+        } else
+                k->n_ref--;
+
+        return NULL;
+}
+
+const char* dns_resource_key_name(const DnsResourceKey *key) {
+        const char *name;
+
+        if (!key)
+                return NULL;
+
+        if (key->_name)
+                name = key->_name;
+        else
+                name = (char*) key + sizeof(DnsResourceKey);
+
+        if (dns_name_is_root(name))
+                return ".";
+        else
+                return name;
+}
+
+bool dns_resource_key_is_address(const DnsResourceKey *key) {
+        assert(key);
+
+        /* Check if this is an A or AAAA resource key */
+
+        return key->class == DNS_CLASS_IN && IN_SET(key->type, DNS_TYPE_A, DNS_TYPE_AAAA);
+}
+
+int dns_resource_key_equal(const DnsResourceKey *a, const DnsResourceKey *b) {
+        int r;
+
+        if (a == b)
+                return 1;
+
+        r = dns_name_equal(dns_resource_key_name(a), dns_resource_key_name(b));
+        if (r <= 0)
+                return r;
+
+        if (a->class != b->class)
+                return 0;
+
+        if (a->type != b->type)
+                return 0;
+
+        return 1;
+}
+
+int dns_resource_key_match_rr(const DnsResourceKey *key, DnsResourceRecord *rr, const char *search_domain) {
+        int r;
+
+        assert(key);
+        assert(rr);
+
+        if (key == rr->key)
+                return 1;
+
+        /* Checks if an rr matches the specified key. If a search
+         * domain is specified, it will also be checked if the key
+         * with the search domain suffixed might match the RR. */
+
+        if (rr->key->class != key->class && key->class != DNS_CLASS_ANY)
+                return 0;
+
+        if (rr->key->type != key->type && key->type != DNS_TYPE_ANY)
+                return 0;
+
+        r = dns_name_equal(dns_resource_key_name(rr->key), dns_resource_key_name(key));
+        if (r != 0)
+                return r;
+
+        if (search_domain) {
+                _cleanup_free_ char *joined = NULL;
+
+                r = dns_name_concat(dns_resource_key_name(key), search_domain, &joined);
+                if (r < 0)
+                        return r;
+
+                return dns_name_equal(dns_resource_key_name(rr->key), joined);
+        }
+
+        return 0;
+}
+
+int dns_resource_key_match_cname_or_dname(const DnsResourceKey *key, const DnsResourceKey *cname, const char *search_domain) {
+        int r;
+
+        assert(key);
+        assert(cname);
+
+        if (cname->class != key->class && key->class != DNS_CLASS_ANY)
+                return 0;
+
+        if (cname->type == DNS_TYPE_CNAME)
+                r = dns_name_equal(dns_resource_key_name(key), dns_resource_key_name(cname));
+        else if (cname->type == DNS_TYPE_DNAME)
+                r = dns_name_endswith(dns_resource_key_name(key), dns_resource_key_name(cname));
+        else
+                return 0;
+
+        if (r != 0)
+                return r;
+
+        if (search_domain) {
+                _cleanup_free_ char *joined = NULL;
+
+                r = dns_name_concat(dns_resource_key_name(key), search_domain, &joined);
+                if (r < 0)
+                        return r;
+
+                if (cname->type == DNS_TYPE_CNAME)
+                        return dns_name_equal(joined, dns_resource_key_name(cname));
+                else if (cname->type == DNS_TYPE_DNAME)
+                        return dns_name_endswith(joined, dns_resource_key_name(cname));
+        }
+
+        return 0;
+}
+
+int dns_resource_key_match_soa(const DnsResourceKey *key, const DnsResourceKey *soa) {
+        assert(soa);
+        assert(key);
+
+        /* Checks whether 'soa' is a SOA record for the specified key. */
+
+        if (soa->class != key->class)
+                return 0;
+
+        if (soa->type != DNS_TYPE_SOA)
+                return 0;
+
+        return dns_name_endswith(dns_resource_key_name(key), dns_resource_key_name(soa));
+}
+
+static void dns_resource_key_hash_func(const void *i, struct siphash *state) {
+        const DnsResourceKey *k = i;
+
+        assert(k);
+
+        dns_name_hash_func(dns_resource_key_name(k), state);
+        siphash24_compress(&k->class, sizeof(k->class), state);
+        siphash24_compress(&k->type, sizeof(k->type), state);
+}
+
+static int dns_resource_key_compare_func(const void *a, const void *b) {
+        const DnsResourceKey *x = a, *y = b;
+        int ret;
+
+        ret = dns_name_compare_func(dns_resource_key_name(x), dns_resource_key_name(y));
+        if (ret != 0)
+                return ret;
+
+        if (x->type < y->type)
+                return -1;
+        if (x->type > y->type)
+                return 1;
+
+        if (x->class < y->class)
+                return -1;
+        if (x->class > y->class)
+                return 1;
+
+        return 0;
+}
+
+const struct hash_ops dns_resource_key_hash_ops = {
+        .hash = dns_resource_key_hash_func,
+        .compare = dns_resource_key_compare_func
+};
+
+char* dns_resource_key_to_string(const DnsResourceKey *key, char *buf, size_t buf_size) {
+        const char *c, *t;
+        char *ans = buf;
+
+        /* If we cannot convert the CLASS/TYPE into a known string,
+           use the format recommended by RFC 3597, Section 5. */
+
+        c = dns_class_to_string(key->class);
+        t = dns_type_to_string(key->type);
+
+        snprintf(buf, buf_size, "%s %s%s%.0u %s%s%.0u",
+                 dns_resource_key_name(key),
+                 c ?: "", c ? "" : "CLASS", c ? 0 : key->class,
+                 t ?: "", t ? "" : "TYPE", t ? 0 : key->class);
+
+        return ans;
+}
+
+bool dns_resource_key_reduce(DnsResourceKey **a, DnsResourceKey **b) {
+        assert(a);
+        assert(b);
+
+        /* Try to replace one RR key by another if they are identical, thus saving a bit of memory. Note that we do
+         * this only for RR keys, not for RRs themselves, as they carry a lot of additional metadata (where they come
+         * from, validity data, and suchlike), and cannot be replaced so easily by other RRs that have the same
+         * superficial data. */
+
+        if (!*a)
+                return false;
+        if (!*b)
+                return false;
+
+        /* We refuse merging const keys */
+        if ((*a)->n_ref == (unsigned) -1)
+                return false;
+        if ((*b)->n_ref == (unsigned) -1)
+                return false;
+
+        /* Already the same? */
+        if (*a == *b)
+                return true;
+
+        /* Are they really identical? */
+        if (dns_resource_key_equal(*a, *b) <= 0)
+                return false;
+
+        /* Keep the one which already has more references. */
+        if ((*a)->n_ref > (*b)->n_ref) {
+                dns_resource_key_unref(*b);
+                *b = dns_resource_key_ref(*a);
+        } else {
+                dns_resource_key_unref(*a);
+                *a = dns_resource_key_ref(*b);
+        }
+
+        return true;
+}
+
+DnsResourceRecord* dns_resource_record_new(DnsResourceKey *key) {
+        DnsResourceRecord *rr;
+
+        rr = new0(DnsResourceRecord, 1);
+        if (!rr)
+                return NULL;
+
+        rr->n_ref = 1;
+        rr->key = dns_resource_key_ref(key);
+        rr->expiry = USEC_INFINITY;
+        rr->n_skip_labels_signer = rr->n_skip_labels_source = (unsigned) -1;
+
+        return rr;
+}
+
+DnsResourceRecord* dns_resource_record_new_full(uint16_t class, uint16_t type, const char *name) {
+        _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL;
+
+        key = dns_resource_key_new(class, type, name);
+        if (!key)
+                return NULL;
+
+        return dns_resource_record_new(key);
+}
+
+DnsResourceRecord* dns_resource_record_ref(DnsResourceRecord *rr) {
+        if (!rr)
+                return NULL;
+
+        assert(rr->n_ref > 0);
+        rr->n_ref++;
+
+        return rr;
+}
+
+DnsResourceRecord* dns_resource_record_unref(DnsResourceRecord *rr) {
+        if (!rr)
+                return NULL;
+
+        assert(rr->n_ref > 0);
+
+        if (rr->n_ref > 1) {
+                rr->n_ref--;
+                return NULL;
+        }
+
+        if (rr->key) {
+                switch(rr->key->type) {
+
+                case DNS_TYPE_SRV:
+                        free(rr->srv.name);
+                        break;
+
+                case DNS_TYPE_PTR:
+                case DNS_TYPE_NS:
+                case DNS_TYPE_CNAME:
+                case DNS_TYPE_DNAME:
+                        free(rr->ptr.name);
+                        break;
+
+                case DNS_TYPE_HINFO:
+                        free(rr->hinfo.cpu);
+                        free(rr->hinfo.os);
+                        break;
+
+                case DNS_TYPE_TXT:
+                case DNS_TYPE_SPF:
+                        dns_txt_item_free_all(rr->txt.items);
+                        break;
+
+                case DNS_TYPE_SOA:
+                        free(rr->soa.mname);
+                        free(rr->soa.rname);
+                        break;
+
+                case DNS_TYPE_MX:
+                        free(rr->mx.exchange);
+                        break;
+
+                case DNS_TYPE_DS:
+                        free(rr->ds.digest);
+                        break;
+
+                case DNS_TYPE_SSHFP:
+                        free(rr->sshfp.fingerprint);
+                        break;
+
+                case DNS_TYPE_DNSKEY:
+                        free(rr->dnskey.key);
+                        break;
+
+                case DNS_TYPE_RRSIG:
+                        free(rr->rrsig.signer);
+                        free(rr->rrsig.signature);
+                        break;
+
+                case DNS_TYPE_NSEC:
+                        free(rr->nsec.next_domain_name);
+                        bitmap_free(rr->nsec.types);
+                        break;
+
+                case DNS_TYPE_NSEC3:
+                        free(rr->nsec3.next_hashed_name);
+                        free(rr->nsec3.salt);
+                        bitmap_free(rr->nsec3.types);
+                        break;
+
+                case DNS_TYPE_LOC:
+                case DNS_TYPE_A:
+                case DNS_TYPE_AAAA:
+                        break;
+
+                case DNS_TYPE_TLSA:
+                        free(rr->tlsa.data);
+                        break;
+
+                case DNS_TYPE_CAA:
+                        free(rr->caa.tag);
+                        free(rr->caa.value);
+                        break;
+
+                case DNS_TYPE_OPENPGPKEY:
+                default:
+                        free(rr->generic.data);
+                }
+
+                free(rr->wire_format);
+                dns_resource_key_unref(rr->key);
+        }
+
+        free(rr->to_string);
+        free(rr);
+
+        return NULL;
+}
+
+int dns_resource_record_new_reverse(DnsResourceRecord **ret, int family, const union in_addr_union *address, const char *hostname) {
+        _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL;
+        _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
+        _cleanup_free_ char *ptr = NULL;
+        int r;
+
+        assert(ret);
+        assert(address);
+        assert(hostname);
+
+        r = dns_name_reverse(family, address, &ptr);
+        if (r < 0)
+                return r;
+
+        key = dns_resource_key_new_consume(DNS_CLASS_IN, DNS_TYPE_PTR, ptr);
+        if (!key)
+                return -ENOMEM;
+
+        ptr = NULL;
+
+        rr = dns_resource_record_new(key);
+        if (!rr)
+                return -ENOMEM;
+
+        rr->ptr.name = strdup(hostname);
+        if (!rr->ptr.name)
+                return -ENOMEM;
+
+        *ret = rr;
+        rr = NULL;
+
+        return 0;
+}
+
+int dns_resource_record_new_address(DnsResourceRecord **ret, int family, const union in_addr_union *address, const char *name) {
+        DnsResourceRecord *rr;
+
+        assert(ret);
+        assert(address);
+        assert(family);
+
+        if (family == AF_INET) {
+
+                rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_A, name);
+                if (!rr)
+                        return -ENOMEM;
+
+                rr->a.in_addr = address->in;
+
+        } else if (family == AF_INET6) {
+
+                rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_AAAA, name);
+                if (!rr)
+                        return -ENOMEM;
+
+                rr->aaaa.in6_addr = address->in6;
+        } else
+                return -EAFNOSUPPORT;
+
+        *ret = rr;
+
+        return 0;
+}
+
+#define FIELD_EQUAL(a, b, field) \
+        ((a).field ## _size == (b).field ## _size &&  \
+         memcmp((a).field, (b).field, (a).field ## _size) == 0)
+
+int dns_resource_record_equal(const DnsResourceRecord *a, const DnsResourceRecord *b) {
+        int r;
+
+        assert(a);
+        assert(b);
+
+        if (a == b)
+                return 1;
+
+        r = dns_resource_key_equal(a->key, b->key);
+        if (r <= 0)
+                return r;
+
+        if (a->unparseable != b->unparseable)
+                return 0;
+
+        switch (a->unparseable ? _DNS_TYPE_INVALID : a->key->type) {
+
+        case DNS_TYPE_SRV:
+                r = dns_name_equal(a->srv.name, b->srv.name);
+                if (r <= 0)
+                        return r;
+
+                return a->srv.priority == b->srv.priority &&
+                       a->srv.weight == b->srv.weight &&
+                       a->srv.port == b->srv.port;
+
+        case DNS_TYPE_PTR:
+        case DNS_TYPE_NS:
+        case DNS_TYPE_CNAME:
+        case DNS_TYPE_DNAME:
+                return dns_name_equal(a->ptr.name, b->ptr.name);
+
+        case DNS_TYPE_HINFO:
+                return strcaseeq(a->hinfo.cpu, b->hinfo.cpu) &&
+                       strcaseeq(a->hinfo.os, b->hinfo.os);
+
+        case DNS_TYPE_SPF: /* exactly the same as TXT */
+        case DNS_TYPE_TXT:
+                return dns_txt_item_equal(a->txt.items, b->txt.items);
+
+        case DNS_TYPE_A:
+                return memcmp(&a->a.in_addr, &b->a.in_addr, sizeof(struct in_addr)) == 0;
+
+        case DNS_TYPE_AAAA:
+                return memcmp(&a->aaaa.in6_addr, &b->aaaa.in6_addr, sizeof(struct in6_addr)) == 0;
+
+        case DNS_TYPE_SOA:
+                r = dns_name_equal(a->soa.mname, b->soa.mname);
+                if (r <= 0)
+                        return r;
+                r = dns_name_equal(a->soa.rname, b->soa.rname);
+                if (r <= 0)
+                        return r;
+
+                return a->soa.serial  == b->soa.serial &&
+                       a->soa.refresh == b->soa.refresh &&
+                       a->soa.retry   == b->soa.retry &&
+                       a->soa.expire  == b->soa.expire &&
+                       a->soa.minimum == b->soa.minimum;
+
+        case DNS_TYPE_MX:
+                if (a->mx.priority != b->mx.priority)
+                        return 0;
+
+                return dns_name_equal(a->mx.exchange, b->mx.exchange);
+
+        case DNS_TYPE_LOC:
+                assert(a->loc.version == b->loc.version);
+
+                return a->loc.size == b->loc.size &&
+                       a->loc.horiz_pre == b->loc.horiz_pre &&
+                       a->loc.vert_pre == b->loc.vert_pre &&
+                       a->loc.latitude == b->loc.latitude &&
+                       a->loc.longitude == b->loc.longitude &&
+                       a->loc.altitude == b->loc.altitude;
+
+        case DNS_TYPE_DS:
+                return a->ds.key_tag == b->ds.key_tag &&
+                       a->ds.algorithm == b->ds.algorithm &&
+                       a->ds.digest_type == b->ds.digest_type &&
+                       FIELD_EQUAL(a->ds, b->ds, digest);
+
+        case DNS_TYPE_SSHFP:
+                return a->sshfp.algorithm == b->sshfp.algorithm &&
+                       a->sshfp.fptype == b->sshfp.fptype &&
+                       FIELD_EQUAL(a->sshfp, b->sshfp, fingerprint);
+
+        case DNS_TYPE_DNSKEY:
+                return a->dnskey.flags == b->dnskey.flags &&
+                       a->dnskey.protocol == b->dnskey.protocol &&
+                       a->dnskey.algorithm == b->dnskey.algorithm &&
+                       FIELD_EQUAL(a->dnskey, b->dnskey, key);
+
+        case DNS_TYPE_RRSIG:
+                /* do the fast comparisons first */
+                return a->rrsig.type_covered == b->rrsig.type_covered &&
+                       a->rrsig.algorithm == b->rrsig.algorithm &&
+                       a->rrsig.labels == b->rrsig.labels &&
+                       a->rrsig.original_ttl == b->rrsig.original_ttl &&
+                       a->rrsig.expiration == b->rrsig.expiration &&
+                       a->rrsig.inception == b->rrsig.inception &&
+                       a->rrsig.key_tag == b->rrsig.key_tag &&
+                       FIELD_EQUAL(a->rrsig, b->rrsig, signature) &&
+                       dns_name_equal(a->rrsig.signer, b->rrsig.signer);
+
+        case DNS_TYPE_NSEC:
+                return dns_name_equal(a->nsec.next_domain_name, b->nsec.next_domain_name) &&
+                       bitmap_equal(a->nsec.types, b->nsec.types);
+
+        case DNS_TYPE_NSEC3:
+                return a->nsec3.algorithm == b->nsec3.algorithm &&
+                       a->nsec3.flags == b->nsec3.flags &&
+                       a->nsec3.iterations == b->nsec3.iterations &&
+                       FIELD_EQUAL(a->nsec3, b->nsec3, salt) &&
+                       FIELD_EQUAL(a->nsec3, b->nsec3, next_hashed_name) &&
+                       bitmap_equal(a->nsec3.types, b->nsec3.types);
+
+        case DNS_TYPE_TLSA:
+                return a->tlsa.cert_usage == b->tlsa.cert_usage &&
+                       a->tlsa.selector == b->tlsa.selector &&
+                       a->tlsa.matching_type == b->tlsa.matching_type &&
+                       FIELD_EQUAL(a->tlsa, b->tlsa, data);
+
+        case DNS_TYPE_CAA:
+                return a->caa.flags == b->caa.flags &&
+                       streq(a->caa.tag, b->caa.tag) &&
+                       FIELD_EQUAL(a->caa, b->caa, value);
+
+        case DNS_TYPE_OPENPGPKEY:
+        default:
+                return FIELD_EQUAL(a->generic, b->generic, data);
+        }
+}
+
+static char* format_location(uint32_t latitude, uint32_t longitude, uint32_t altitude,
+                             uint8_t size, uint8_t horiz_pre, uint8_t vert_pre) {
+        char *s;
+        char NS = latitude >= 1U<<31 ? 'N' : 'S';
+        char EW = longitude >= 1U<<31 ? 'E' : 'W';
+
+        int lat = latitude >= 1U<<31 ? (int) (latitude - (1U<<31)) : (int) ((1U<<31) - latitude);
+        int lon = longitude >= 1U<<31 ? (int) (longitude - (1U<<31)) : (int) ((1U<<31) - longitude);
+        double alt = altitude >= 10000000u ? altitude - 10000000u : -(double)(10000000u - altitude);
+        double siz = (size >> 4) * exp10((double) (size & 0xF));
+        double hor = (horiz_pre >> 4) * exp10((double) (horiz_pre & 0xF));
+        double ver = (vert_pre >> 4) * exp10((double) (vert_pre & 0xF));
+
+        if (asprintf(&s, "%d %d %.3f %c %d %d %.3f %c %.2fm %.2fm %.2fm %.2fm",
+                     (lat / 60000 / 60),
+                     (lat / 60000) % 60,
+                     (lat % 60000) / 1000.,
+                     NS,
+                     (lon / 60000 / 60),
+                     (lon / 60000) % 60,
+                     (lon % 60000) / 1000.,
+                     EW,
+                     alt / 100.,
+                     siz / 100.,
+                     hor / 100.,
+                     ver / 100.) < 0)
+                return NULL;
+
+        return s;
+}
+
+static int format_timestamp_dns(char *buf, size_t l, time_t sec) {
+        struct tm tm;
+
+        assert(buf);
+        assert(l > strlen("YYYYMMDDHHmmSS"));
+
+        if (!gmtime_r(&sec, &tm))
+                return -EINVAL;
+
+        if (strftime(buf, l, "%Y%m%d%H%M%S", &tm) <= 0)
+                return -EINVAL;
+
+        return 0;
+}
+
+static char *format_types(Bitmap *types) {
+        _cleanup_strv_free_ char **strv = NULL;
+        _cleanup_free_ char *str = NULL;
+        Iterator i;
+        unsigned type;
+        int r;
+
+        BITMAP_FOREACH(type, types, i) {
+                if (dns_type_to_string(type)) {
+                        r = strv_extend(&strv, dns_type_to_string(type));
+                        if (r < 0)
+                                return NULL;
+                } else {
+                        char *t;
+
+                        r = asprintf(&t, "TYPE%u", type);
+                        if (r < 0)
+                                return NULL;
+
+                        r = strv_consume(&strv, t);
+                        if (r < 0)
+                                return NULL;
+                }
+        }
+
+        str = strv_join(strv, " ");
+        if (!str)
+                return NULL;
+
+        return strjoin("( ", str, " )", NULL);
+}
+
+static char *format_txt(DnsTxtItem *first) {
+        DnsTxtItem *i;
+        size_t c = 1;
+        char *p, *s;
+
+        LIST_FOREACH(items, i, first)
+                c += i->length * 4 + 3;
+
+        p = s = new(char, c);
+        if (!s)
+                return NULL;
+
+        LIST_FOREACH(items, i, first) {
+                size_t j;
+
+                if (i != first)
+                        *(p++) = ' ';
+
+                *(p++) = '"';
+
+                for (j = 0; j < i->length; j++) {
+                        if (i->data[j] < ' ' || i->data[j] == '"' || i->data[j] >= 127) {
+                                *(p++) = '\\';
+                                *(p++) = '0' + (i->data[j] / 100);
+                                *(p++) = '0' + ((i->data[j] / 10) % 10);
+                                *(p++) = '0' + (i->data[j] % 10);
+                        } else
+                                *(p++) = i->data[j];
+                }
+
+                *(p++) = '"';
+        }
+
+        *p = 0;
+        return s;
+}
+
+const char *dns_resource_record_to_string(DnsResourceRecord *rr) {
+        _cleanup_free_ char *t = NULL;
+        char *s, k[DNS_RESOURCE_KEY_STRING_MAX];
+        int r;
+
+        assert(rr);
+
+        if (rr->to_string)
+                return rr->to_string;
+
+        dns_resource_key_to_string(rr->key, k, sizeof(k));
+
+        switch (rr->unparseable ? _DNS_TYPE_INVALID : rr->key->type) {
+
+        case DNS_TYPE_SRV:
+                r = asprintf(&s, "%s %u %u %u %s",
+                             k,
+                             rr->srv.priority,
+                             rr->srv.weight,
+                             rr->srv.port,
+                             strna(rr->srv.name));
+                if (r < 0)
+                        return NULL;
+                break;
+
+        case DNS_TYPE_PTR:
+        case DNS_TYPE_NS:
+        case DNS_TYPE_CNAME:
+        case DNS_TYPE_DNAME:
+                s = strjoin(k, " ", rr->ptr.name, NULL);
+                if (!s)
+                        return NULL;
+
+                break;
+
+        case DNS_TYPE_HINFO:
+                s = strjoin(k, " ", rr->hinfo.cpu, " ", rr->hinfo.os, NULL);
+                if (!s)
+                        return NULL;
+                break;
+
+        case DNS_TYPE_SPF: /* exactly the same as TXT */
+        case DNS_TYPE_TXT:
+                t = format_txt(rr->txt.items);
+                if (!t)
+                        return NULL;
+
+                s = strjoin(k, " ", t, NULL);
+                if (!s)
+                        return NULL;
+                break;
+
+        case DNS_TYPE_A: {
+                _cleanup_free_ char *x = NULL;
+
+                r = in_addr_to_string(AF_INET, (const union in_addr_union*) &rr->a.in_addr, &x);
+                if (r < 0)
+                        return NULL;
+
+                s = strjoin(k, " ", x, NULL);
+                if (!s)
+                        return NULL;
+                break;
+        }
+
+        case DNS_TYPE_AAAA:
+                r = in_addr_to_string(AF_INET6, (const union in_addr_union*) &rr->aaaa.in6_addr, &t);
+                if (r < 0)
+                        return NULL;
+
+                s = strjoin(k, " ", t, NULL);
+                if (!s)
+                        return NULL;
+                break;
+
+        case DNS_TYPE_SOA:
+                r = asprintf(&s, "%s %s %s %u %u %u %u %u",
+                             k,
+                             strna(rr->soa.mname),
+                             strna(rr->soa.rname),
+                             rr->soa.serial,
+                             rr->soa.refresh,
+                             rr->soa.retry,
+                             rr->soa.expire,
+                             rr->soa.minimum);
+                if (r < 0)
+                        return NULL;
+                break;
+
+        case DNS_TYPE_MX:
+                r = asprintf(&s, "%s %u %s",
+                             k,
+                             rr->mx.priority,
+                             rr->mx.exchange);
+                if (r < 0)
+                        return NULL;
+                break;
+
+        case DNS_TYPE_LOC:
+                assert(rr->loc.version == 0);
+
+                t = format_location(rr->loc.latitude,
+                                    rr->loc.longitude,
+                                    rr->loc.altitude,
+                                    rr->loc.size,
+                                    rr->loc.horiz_pre,
+                                    rr->loc.vert_pre);
+                if (!t)
+                        return NULL;
+
+                s = strjoin(k, " ", t, NULL);
+                if (!s)
+                        return NULL;
+                break;
+
+        case DNS_TYPE_DS:
+                t = hexmem(rr->ds.digest, rr->ds.digest_size);
+                if (!t)
+                        return NULL;
+
+                r = asprintf(&s, "%s %u %u %u %s",
+                             k,
+                             rr->ds.key_tag,
+                             rr->ds.algorithm,
+                             rr->ds.digest_type,
+                             t);
+                if (r < 0)
+                        return NULL;
+                break;
+
+        case DNS_TYPE_SSHFP:
+                t = hexmem(rr->sshfp.fingerprint, rr->sshfp.fingerprint_size);
+                if (!t)
+                        return NULL;
+
+                r = asprintf(&s, "%s %u %u %s",
+                             k,
+                             rr->sshfp.algorithm,
+                             rr->sshfp.fptype,
+                             t);
+                if (r < 0)
+                        return NULL;
+                break;
+
+        case DNS_TYPE_DNSKEY: {
+                _cleanup_free_ char *alg = NULL;
+                char *ss;
+                int n;
+                uint16_t key_tag;
+
+                key_tag = dnssec_keytag(rr, true);
+
+                r = dnssec_algorithm_to_string_alloc(rr->dnskey.algorithm, &alg);
+                if (r < 0)
+                        return NULL;
+
+                r = asprintf(&s, "%s %u %u %s %n",
+                             k,
+                             rr->dnskey.flags,
+                             rr->dnskey.protocol,
+                             alg,
+                             &n);
+                if (r < 0)
+                        return NULL;
+
+                r = base64_append(&s, n,
+                                  rr->dnskey.key, rr->dnskey.key_size,
+                                  8, columns());
+                if (r < 0)
+                        return NULL;
+
+                r = asprintf(&ss, "%s\n"
+                             "        -- Flags:%s%s%s\n"
+                             "        -- Key tag: %u",
+                             s,
+                             rr->dnskey.flags & DNSKEY_FLAG_SEP ? " SEP" : "",
+                             rr->dnskey.flags & DNSKEY_FLAG_REVOKE ? " REVOKE" : "",
+                             rr->dnskey.flags & DNSKEY_FLAG_ZONE_KEY ? " ZONE_KEY" : "",
+                             key_tag);
+                if (r < 0)
+                        return NULL;
+                free(s);
+                s = ss;
+
+                break;
+        }
+
+        case DNS_TYPE_RRSIG: {
+                _cleanup_free_ char *alg = NULL;
+                char expiration[strlen("YYYYMMDDHHmmSS") + 1], inception[strlen("YYYYMMDDHHmmSS") + 1];
+                const char *type;
+                int n;
+
+                type = dns_type_to_string(rr->rrsig.type_covered);
+
+                r = dnssec_algorithm_to_string_alloc(rr->rrsig.algorithm, &alg);
+                if (r < 0)
+                        return NULL;
+
+                r = format_timestamp_dns(expiration, sizeof(expiration), rr->rrsig.expiration);
+                if (r < 0)
+                        return NULL;
+
+                r = format_timestamp_dns(inception, sizeof(inception), rr->rrsig.inception);
+                if (r < 0)
+                        return NULL;
+
+                /* TYPE?? follows
+                 * http://tools.ietf.org/html/rfc3597#section-5 */
+
+                r = asprintf(&s, "%s %s%.*u %s %u %u %s %s %u %s %n",
+                             k,
+                             type ?: "TYPE",
+                             type ? 0 : 1, type ? 0u : (unsigned) rr->rrsig.type_covered,
+                             alg,
+                             rr->rrsig.labels,
+                             rr->rrsig.original_ttl,
+                             expiration,
+                             inception,
+                             rr->rrsig.key_tag,
+                             rr->rrsig.signer,
+                             &n);
+                if (r < 0)
+                        return NULL;
+
+                r = base64_append(&s, n,
+                                  rr->rrsig.signature, rr->rrsig.signature_size,
+                                  8, columns());
+                if (r < 0)
+                        return NULL;
+
+                break;
+        }
+
+        case DNS_TYPE_NSEC:
+                t = format_types(rr->nsec.types);
+                if (!t)
+                        return NULL;
+
+                r = asprintf(&s, "%s %s %s",
+                             k,
+                             rr->nsec.next_domain_name,
+                             t);
+                if (r < 0)
+                        return NULL;
+                break;
+
+        case DNS_TYPE_NSEC3: {
+                _cleanup_free_ char *salt = NULL, *hash = NULL;
+
+                if (rr->nsec3.salt_size > 0) {
+                        salt = hexmem(rr->nsec3.salt, rr->nsec3.salt_size);
+                        if (!salt)
+                                return NULL;
+                }
+
+                hash = base32hexmem(rr->nsec3.next_hashed_name, rr->nsec3.next_hashed_name_size, false);
+                if (!hash)
+                        return NULL;
+
+                t = format_types(rr->nsec3.types);
+                if (!t)
+                        return NULL;
+
+                r = asprintf(&s, "%s %"PRIu8" %"PRIu8" %"PRIu16" %s %s %s",
+                             k,
+                             rr->nsec3.algorithm,
+                             rr->nsec3.flags,
+                             rr->nsec3.iterations,
+                             rr->nsec3.salt_size > 0 ? salt : "-",
+                             hash,
+                             t);
+                if (r < 0)
+                        return NULL;
+
+                break;
+        }
+
+        case DNS_TYPE_TLSA: {
+                const char *cert_usage, *selector, *matching_type;
+
+                cert_usage = tlsa_cert_usage_to_string(rr->tlsa.cert_usage);
+                selector = tlsa_selector_to_string(rr->tlsa.selector);
+                matching_type = tlsa_matching_type_to_string(rr->tlsa.matching_type);
+
+                t = hexmem(rr->sshfp.fingerprint, rr->sshfp.fingerprint_size);
+                if (!t)
+                        return NULL;
+
+                r = asprintf(&s,
+                             "%s %u %u %u %s\n"
+                             "        -- Cert. usage: %s\n"
+                             "        -- Selector: %s\n"
+                             "        -- Matching type: %s",
+                             k,
+                             rr->tlsa.cert_usage,
+                             rr->tlsa.selector,
+                             rr->tlsa.matching_type,
+                             t,
+                             cert_usage,
+                             selector,
+                             matching_type);
+                if (r < 0)
+                        return NULL;
+
+                break;
+        }
+
+        case DNS_TYPE_CAA: {
+                _cleanup_free_ char *value;
+
+                value = octescape(rr->caa.value, rr->caa.value_size);
+                if (!value)
+                        return NULL;
+
+                r = asprintf(&s, "%s %u %s \"%s\"%s%s%s%.0u",
+                             k,
+                             rr->caa.flags,
+                             rr->caa.tag,
+                             value,
+                             rr->caa.flags ? "\n        -- Flags:" : "",
+                             rr->caa.flags & CAA_FLAG_CRITICAL ? " critical" : "",
+                             rr->caa.flags & ~CAA_FLAG_CRITICAL ? " " : "",
+                             rr->caa.flags & ~CAA_FLAG_CRITICAL);
+                if (r < 0)
+                        return NULL;
+
+                break;
+        }
+
+        case DNS_TYPE_OPENPGPKEY: {
+                int n;
+
+                r = asprintf(&s, "%s %n",
+                             k,
+                             &n);
+                if (r < 0)
+                        return NULL;
+
+                r = base64_append(&s, n,
+                                  rr->generic.data, rr->generic.data_size,
+                                  8, columns());
+                if (r < 0)
+                        return NULL;
+                break;
+        }
+
+        default:
+                t = hexmem(rr->generic.data, rr->generic.data_size);
+                if (!t)
+                        return NULL;
+
+                /* Format as documented in RFC 3597, Section 5 */
+                r = asprintf(&s, "%s \\# %zu %s", k, rr->generic.data_size, t);
+                if (r < 0)
+                        return NULL;
+                break;
+        }
+
+        rr->to_string = s;
+        return s;
+}
+
+ssize_t dns_resource_record_payload(DnsResourceRecord *rr, void **out) {
+        assert(rr);
+        assert(out);
+
+        switch(rr->unparseable ? _DNS_TYPE_INVALID : rr->key->type) {
+        case DNS_TYPE_SRV:
+        case DNS_TYPE_PTR:
+        case DNS_TYPE_NS:
+        case DNS_TYPE_CNAME:
+        case DNS_TYPE_DNAME:
+        case DNS_TYPE_HINFO:
+        case DNS_TYPE_SPF:
+        case DNS_TYPE_TXT:
+        case DNS_TYPE_A:
+        case DNS_TYPE_AAAA:
+        case DNS_TYPE_SOA:
+        case DNS_TYPE_MX:
+        case DNS_TYPE_LOC:
+        case DNS_TYPE_DS:
+        case DNS_TYPE_DNSKEY:
+        case DNS_TYPE_RRSIG:
+        case DNS_TYPE_NSEC:
+        case DNS_TYPE_NSEC3:
+                return -EINVAL;
+
+        case DNS_TYPE_SSHFP:
+                *out = rr->sshfp.fingerprint;
+                return rr->sshfp.fingerprint_size;
+
+        case DNS_TYPE_TLSA:
+                *out = rr->tlsa.data;
+                return rr->tlsa.data_size;
+
+
+        case DNS_TYPE_OPENPGPKEY:
+        default:
+                *out = rr->generic.data;
+                return rr->generic.data_size;
+        }
+}
+
+int dns_resource_record_to_wire_format(DnsResourceRecord *rr, bool canonical) {
+
+        DnsPacket packet = {
+                .n_ref = 1,
+                .protocol = DNS_PROTOCOL_DNS,
+                .on_stack = true,
+                .refuse_compression = true,
+                .canonical_form = canonical,
+        };
+
+        size_t start, rds;
+        int r;
+
+        assert(rr);
+
+        /* Generates the RR in wire-format, optionally in the
+         * canonical form as discussed in the DNSSEC RFC 4034, Section
+         * 6.2. We allocate a throw-away DnsPacket object on the stack
+         * here, because we need some book-keeping for memory
+         * management, and can reuse the DnsPacket serializer, that
+         * can generate the canonical form, too, but also knows label
+         * compression and suchlike. */
+
+        if (rr->wire_format && rr->wire_format_canonical == canonical)
+                return 0;
+
+        r = dns_packet_append_rr(&packet, rr, &start, &rds);
+        if (r < 0)
+                return r;
+
+        assert(start == 0);
+        assert(packet._data);
+
+        free(rr->wire_format);
+        rr->wire_format = packet._data;
+        rr->wire_format_size = packet.size;
+        rr->wire_format_rdata_offset = rds;
+        rr->wire_format_canonical = canonical;
+
+        packet._data = NULL;
+        dns_packet_unref(&packet);
+
+        return 0;
+}
+
+int dns_resource_record_signer(DnsResourceRecord *rr, const char **ret) {
+        const char *n;
+        int r;
+
+        assert(rr);
+        assert(ret);
+
+        /* Returns the RRset's signer, if it is known. */
+
+        if (rr->n_skip_labels_signer == (unsigned) -1)
+                return -ENODATA;
+
+        n = dns_resource_key_name(rr->key);
+        r = dns_name_skip(n, rr->n_skip_labels_signer, &n);
+        if (r < 0)
+                return r;
+        if (r == 0)
+                return -EINVAL;
+
+        *ret = n;
+        return 0;
+}
+
+int dns_resource_record_source(DnsResourceRecord *rr, const char **ret) {
+        const char *n;
+        int r;
+
+        assert(rr);
+        assert(ret);
+
+        /* Returns the RRset's synthesizing source, if it is known. */
+
+        if (rr->n_skip_labels_source == (unsigned) -1)
+                return -ENODATA;
+
+        n = dns_resource_key_name(rr->key);
+        r = dns_name_skip(n, rr->n_skip_labels_source, &n);
+        if (r < 0)
+                return r;
+        if (r == 0)
+                return -EINVAL;
+
+        *ret = n;
+        return 0;
+}
+
+int dns_resource_record_is_signer(DnsResourceRecord *rr, const char *zone) {
+        const char *signer;
+        int r;
+
+        assert(rr);
+
+        r = dns_resource_record_signer(rr, &signer);
+        if (r < 0)
+                return r;
+
+        return dns_name_equal(zone, signer);
+}
+
+int dns_resource_record_is_synthetic(DnsResourceRecord *rr) {
+        int r;
+
+        assert(rr);
+
+        /* Returns > 0 if the RR is generated from a wildcard, and is not the asterisk name itself */
+
+        if (rr->n_skip_labels_source == (unsigned) -1)
+                return -ENODATA;
+
+        if (rr->n_skip_labels_source == 0)
+                return 0;
+
+        if (rr->n_skip_labels_source > 1)
+                return 1;
+
+        r = dns_name_startswith(dns_resource_key_name(rr->key), "*");
+        if (r < 0)
+                return r;
+
+        return !r;
+}
+
+void dns_resource_record_hash_func(const void *i, struct siphash *state) {
+        const DnsResourceRecord *rr = i;
+
+        assert(rr);
+
+        dns_resource_key_hash_func(rr->key, state);
+
+        switch (rr->unparseable ? _DNS_TYPE_INVALID : rr->key->type) {
+
+        case DNS_TYPE_SRV:
+                siphash24_compress(&rr->srv.priority, sizeof(rr->srv.priority), state);
+                siphash24_compress(&rr->srv.weight, sizeof(rr->srv.weight), state);
+                siphash24_compress(&rr->srv.port, sizeof(rr->srv.port), state);
+                dns_name_hash_func(rr->srv.name, state);
+                break;
+
+        case DNS_TYPE_PTR:
+        case DNS_TYPE_NS:
+        case DNS_TYPE_CNAME:
+        case DNS_TYPE_DNAME:
+                dns_name_hash_func(rr->ptr.name, state);
+                break;
+
+        case DNS_TYPE_HINFO:
+                string_hash_func(rr->hinfo.cpu, state);
+                string_hash_func(rr->hinfo.os, state);
+                break;
+
+        case DNS_TYPE_TXT:
+        case DNS_TYPE_SPF: {
+                DnsTxtItem *j;
+
+                LIST_FOREACH(items, j, rr->txt.items) {
+                        siphash24_compress(j->data, j->length, state);
+
+                        /* Add an extra NUL byte, so that "a" followed by "b" doesn't result in the same hash as "ab"
+                         * followed by "". */
+                        siphash24_compress_byte(0, state);
+                }
+                break;
+        }
+
+        case DNS_TYPE_A:
+                siphash24_compress(&rr->a.in_addr, sizeof(rr->a.in_addr), state);
+                break;
+
+        case DNS_TYPE_AAAA:
+                siphash24_compress(&rr->aaaa.in6_addr, sizeof(rr->aaaa.in6_addr), state);
+                break;
+
+        case DNS_TYPE_SOA:
+                dns_name_hash_func(rr->soa.mname, state);
+                dns_name_hash_func(rr->soa.rname, state);
+                siphash24_compress(&rr->soa.serial, sizeof(rr->soa.serial), state);
+                siphash24_compress(&rr->soa.refresh, sizeof(rr->soa.refresh), state);
+                siphash24_compress(&rr->soa.retry, sizeof(rr->soa.retry), state);
+                siphash24_compress(&rr->soa.expire, sizeof(rr->soa.expire), state);
+                siphash24_compress(&rr->soa.minimum, sizeof(rr->soa.minimum), state);
+                break;
+
+        case DNS_TYPE_MX:
+                siphash24_compress(&rr->mx.priority, sizeof(rr->mx.priority), state);
+                dns_name_hash_func(rr->mx.exchange, state);
+                break;
+
+        case DNS_TYPE_LOC:
+                siphash24_compress(&rr->loc.version, sizeof(rr->loc.version), state);
+                siphash24_compress(&rr->loc.size, sizeof(rr->loc.size), state);
+                siphash24_compress(&rr->loc.horiz_pre, sizeof(rr->loc.horiz_pre), state);
+                siphash24_compress(&rr->loc.vert_pre, sizeof(rr->loc.vert_pre), state);
+                siphash24_compress(&rr->loc.latitude, sizeof(rr->loc.latitude), state);
+                siphash24_compress(&rr->loc.longitude, sizeof(rr->loc.longitude), state);
+                siphash24_compress(&rr->loc.altitude, sizeof(rr->loc.altitude), state);
+                break;
+
+        case DNS_TYPE_SSHFP:
+                siphash24_compress(&rr->sshfp.algorithm, sizeof(rr->sshfp.algorithm), state);
+                siphash24_compress(&rr->sshfp.fptype, sizeof(rr->sshfp.fptype), state);
+                siphash24_compress(rr->sshfp.fingerprint, rr->sshfp.fingerprint_size, state);
+                break;
+
+        case DNS_TYPE_DNSKEY:
+                siphash24_compress(&rr->dnskey.flags, sizeof(rr->dnskey.flags), state);
+                siphash24_compress(&rr->dnskey.protocol, sizeof(rr->dnskey.protocol), state);
+                siphash24_compress(&rr->dnskey.algorithm, sizeof(rr->dnskey.algorithm), state);
+                siphash24_compress(rr->dnskey.key, rr->dnskey.key_size, state);
+                break;
+
+        case DNS_TYPE_RRSIG:
+                siphash24_compress(&rr->rrsig.type_covered, sizeof(rr->rrsig.type_covered), state);
+                siphash24_compress(&rr->rrsig.algorithm, sizeof(rr->rrsig.algorithm), state);
+                siphash24_compress(&rr->rrsig.labels, sizeof(rr->rrsig.labels), state);
+                siphash24_compress(&rr->rrsig.original_ttl, sizeof(rr->rrsig.original_ttl), state);
+                siphash24_compress(&rr->rrsig.expiration, sizeof(rr->rrsig.expiration), state);
+                siphash24_compress(&rr->rrsig.inception, sizeof(rr->rrsig.inception), state);
+                siphash24_compress(&rr->rrsig.key_tag, sizeof(rr->rrsig.key_tag), state);
+                dns_name_hash_func(rr->rrsig.signer, state);
+                siphash24_compress(rr->rrsig.signature, rr->rrsig.signature_size, state);
+                break;
+
+        case DNS_TYPE_NSEC:
+                dns_name_hash_func(rr->nsec.next_domain_name, state);
+                /* FIXME: we leave out the type bitmap here. Hash
+                 * would be better if we'd take it into account
+                 * too. */
+                break;
+
+        case DNS_TYPE_DS:
+                siphash24_compress(&rr->ds.key_tag, sizeof(rr->ds.key_tag), state);
+                siphash24_compress(&rr->ds.algorithm, sizeof(rr->ds.algorithm), state);
+                siphash24_compress(&rr->ds.digest_type, sizeof(rr->ds.digest_type), state);
+                siphash24_compress(rr->ds.digest, rr->ds.digest_size, state);
+                break;
+
+        case DNS_TYPE_NSEC3:
+                siphash24_compress(&rr->nsec3.algorithm, sizeof(rr->nsec3.algorithm), state);
+                siphash24_compress(&rr->nsec3.flags, sizeof(rr->nsec3.flags), state);
+                siphash24_compress(&rr->nsec3.iterations, sizeof(rr->nsec3.iterations), state);
+                siphash24_compress(rr->nsec3.salt, rr->nsec3.salt_size, state);
+                siphash24_compress(rr->nsec3.next_hashed_name, rr->nsec3.next_hashed_name_size, state);
+                /* FIXME: We leave the bitmaps out */
+                break;
+
+        case DNS_TYPE_TLSA:
+                siphash24_compress(&rr->tlsa.cert_usage, sizeof(rr->tlsa.cert_usage), state);
+                siphash24_compress(&rr->tlsa.selector, sizeof(rr->tlsa.selector), state);
+                siphash24_compress(&rr->tlsa.matching_type, sizeof(rr->tlsa.matching_type), state);
+                siphash24_compress(rr->tlsa.data, rr->tlsa.data_size, state);
+                break;
+
+        case DNS_TYPE_CAA:
+                siphash24_compress(&rr->caa.flags, sizeof(rr->caa.flags), state);
+                string_hash_func(rr->caa.tag, state);
+                siphash24_compress(rr->caa.value, rr->caa.value_size, state);
+                break;
+
+        case DNS_TYPE_OPENPGPKEY:
+        default:
+                siphash24_compress(rr->generic.data, rr->generic.data_size, state);
+                break;
+        }
+}
+
+static int dns_resource_record_compare_func(const void *a, const void *b) {
+        const DnsResourceRecord *x = a, *y = b;
+        int ret;
+
+        ret = dns_resource_key_compare_func(x->key, y->key);
+        if (ret != 0)
+                return ret;
+
+        if (dns_resource_record_equal(x, y))
+                return 0;
+
+        /* This is a bit dirty, we don't implement proper ordering, but
+         * the hashtable doesn't need ordering anyway, hence we don't
+         * care. */
+        return x < y ? -1 : 1;
+}
+
+const struct hash_ops dns_resource_record_hash_ops = {
+        .hash = dns_resource_record_hash_func,
+        .compare = dns_resource_record_compare_func,
+};
+
+DnsResourceRecord *dns_resource_record_copy(DnsResourceRecord *rr) {
+        _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *copy = NULL;
+        DnsResourceRecord *t;
+
+        assert(rr);
+
+        copy = dns_resource_record_new(rr->key);
+        if (!copy)
+                return NULL;
+
+        copy->ttl = rr->ttl;
+        copy->expiry = rr->expiry;
+        copy->n_skip_labels_signer = rr->n_skip_labels_signer;
+        copy->n_skip_labels_source = rr->n_skip_labels_source;
+        copy->unparseable = rr->unparseable;
+
+        switch (rr->unparseable ? _DNS_TYPE_INVALID : rr->key->type) {
+
+        case DNS_TYPE_SRV:
+                copy->srv.priority = rr->srv.priority;
+                copy->srv.weight = rr->srv.weight;
+                copy->srv.port = rr->srv.port;
+                copy->srv.name = strdup(rr->srv.name);
+                if (!copy->srv.name)
+                        return NULL;
+                break;
+
+        case DNS_TYPE_PTR:
+        case DNS_TYPE_NS:
+        case DNS_TYPE_CNAME:
+        case DNS_TYPE_DNAME:
+                copy->ptr.name = strdup(rr->ptr.name);
+                if (!copy->ptr.name)
+                        return NULL;
+                break;
+
+        case DNS_TYPE_HINFO:
+                copy->hinfo.cpu = strdup(rr->hinfo.cpu);
+                if (!copy->hinfo.cpu)
+                        return NULL;
+
+                copy->hinfo.os = strdup(rr->hinfo.os);
+                if(!copy->hinfo.os)
+                        return NULL;
+                break;
+
+        case DNS_TYPE_TXT:
+        case DNS_TYPE_SPF:
+                copy->txt.items = dns_txt_item_copy(rr->txt.items);
+                if (!copy->txt.items)
+                        return NULL;
+                break;
+
+        case DNS_TYPE_A:
+                copy->a = rr->a;
+                break;
+
+        case DNS_TYPE_AAAA:
+                copy->aaaa = rr->aaaa;
+                break;
+
+        case DNS_TYPE_SOA:
+                copy->soa.mname = strdup(rr->soa.mname);
+                if (!copy->soa.mname)
+                        return NULL;
+                copy->soa.rname = strdup(rr->soa.rname);
+                if (!copy->soa.rname)
+                        return NULL;
+                copy->soa.serial = rr->soa.serial;
+                copy->soa.refresh = rr->soa.refresh;
+                copy->soa.retry = rr->soa.retry;
+                copy->soa.expire = rr->soa.expire;
+                copy->soa.minimum = rr->soa.minimum;
+                break;
+
+        case DNS_TYPE_MX:
+                copy->mx.priority = rr->mx.priority;
+                copy->mx.exchange = strdup(rr->mx.exchange);
+                if (!copy->mx.exchange)
+                        return NULL;
+                break;
+
+        case DNS_TYPE_LOC:
+                copy->loc = rr->loc;
+                break;
+
+        case DNS_TYPE_SSHFP:
+                copy->sshfp.algorithm = rr->sshfp.algorithm;
+                copy->sshfp.fptype = rr->sshfp.fptype;
+                copy->sshfp.fingerprint = memdup(rr->sshfp.fingerprint, rr->sshfp.fingerprint_size);
+                if (!copy->sshfp.fingerprint)
+                        return NULL;
+                copy->sshfp.fingerprint_size = rr->sshfp.fingerprint_size;
+                break;
+
+        case DNS_TYPE_DNSKEY:
+                copy->dnskey.flags = rr->dnskey.flags;
+                copy->dnskey.protocol = rr->dnskey.protocol;
+                copy->dnskey.algorithm = rr->dnskey.algorithm;
+                copy->dnskey.key = memdup(rr->dnskey.key, rr->dnskey.key_size);
+                if (!copy->dnskey.key)
+                        return NULL;
+                copy->dnskey.key_size = rr->dnskey.key_size;
+                break;
+
+        case DNS_TYPE_RRSIG:
+                copy->rrsig.type_covered = rr->rrsig.type_covered;
+                copy->rrsig.algorithm = rr->rrsig.algorithm;
+                copy->rrsig.labels = rr->rrsig.labels;
+                copy->rrsig.original_ttl = rr->rrsig.original_ttl;
+                copy->rrsig.expiration = rr->rrsig.expiration;
+                copy->rrsig.inception = rr->rrsig.inception;
+                copy->rrsig.key_tag = rr->rrsig.key_tag;
+                copy->rrsig.signer = strdup(rr->rrsig.signer);
+                if (!copy->rrsig.signer)
+                        return NULL;
+                copy->rrsig.signature = memdup(rr->rrsig.signature, rr->rrsig.signature_size);
+                if (!copy->rrsig.signature)
+                        return NULL;
+                copy->rrsig.signature_size = rr->rrsig.signature_size;
+                break;
+
+        case DNS_TYPE_NSEC:
+                copy->nsec.next_domain_name = strdup(rr->nsec.next_domain_name);
+                if (!copy->nsec.next_domain_name)
+                        return NULL;
+                copy->nsec.types = bitmap_copy(rr->nsec.types);
+                if (!copy->nsec.types)
+                        return NULL;
+                break;
+
+        case DNS_TYPE_DS:
+                copy->ds.key_tag = rr->ds.key_tag;
+                copy->ds.algorithm = rr->ds.algorithm;
+                copy->ds.digest_type = rr->ds.digest_type;
+                copy->ds.digest = memdup(rr->ds.digest, rr->ds.digest_size);
+                if (!copy->ds.digest)
+                        return NULL;
+                copy->ds.digest_size = rr->ds.digest_size;
+                break;
+
+        case DNS_TYPE_NSEC3:
+                copy->nsec3.algorithm = rr->nsec3.algorithm;
+                copy->nsec3.flags = rr->nsec3.flags;
+                copy->nsec3.iterations = rr->nsec3.iterations;
+                copy->nsec3.salt = memdup(rr->nsec3.salt, rr->nsec3.salt_size);
+                if (!copy->nsec3.salt)
+                        return NULL;
+                copy->nsec3.salt_size = rr->nsec3.salt_size;
+                copy->nsec3.next_hashed_name = memdup(rr->nsec3.next_hashed_name, rr->nsec3.next_hashed_name_size);
+                if (!copy->nsec3.next_hashed_name_size)
+                        return NULL;
+                copy->nsec3.next_hashed_name_size = rr->nsec3.next_hashed_name_size;
+                copy->nsec3.types = bitmap_copy(rr->nsec3.types);
+                if (!copy->nsec3.types)
+                        return NULL;
+                break;
+
+        case DNS_TYPE_TLSA:
+                copy->tlsa.cert_usage = rr->tlsa.cert_usage;
+                copy->tlsa.selector = rr->tlsa.selector;
+                copy->tlsa.matching_type = rr->tlsa.matching_type;
+                copy->tlsa.data = memdup(rr->tlsa.data, rr->tlsa.data_size);
+                if (!copy->tlsa.data)
+                        return NULL;
+                copy->tlsa.data_size = rr->tlsa.data_size;
+                break;
+
+        case DNS_TYPE_CAA:
+                copy->caa.flags = rr->caa.flags;
+                copy->caa.tag = strdup(rr->caa.tag);
+                if (!copy->caa.tag)
+                        return NULL;
+                copy->caa.value = memdup(rr->caa.value, rr->caa.value_size);
+                if (!copy->caa.value)
+                        return NULL;
+                copy->caa.value_size = rr->caa.value_size;
+                break;
+
+        case DNS_TYPE_OPT:
+        default:
+                copy->generic.data = memdup(rr->generic.data, rr->generic.data_size);
+                if (!copy->generic.data)
+                        return NULL;
+                copy->generic.data_size = rr->generic.data_size;
+                break;
+        }
+
+        t = copy;
+        copy = NULL;
+
+        return t;
+}
+
+int dns_resource_record_clamp_ttl(DnsResourceRecord **rr, uint32_t max_ttl) {
+        DnsResourceRecord *old_rr, *new_rr;
+        uint32_t new_ttl;
+
+        assert(rr);
+        old_rr = *rr;
+
+        if (old_rr->key->type == DNS_TYPE_OPT)
+                return -EINVAL;
+
+        new_ttl = MIN(old_rr->ttl, max_ttl);
+        if (new_ttl == old_rr->ttl)
+                return 0;
+
+        if (old_rr->n_ref == 1) {
+                /* Patch in place */
+                old_rr->ttl = new_ttl;
+                return 1;
+        }
+
+        new_rr = dns_resource_record_copy(old_rr);
+        if (!new_rr)
+                return -ENOMEM;
+
+        new_rr->ttl = new_ttl;
+
+        dns_resource_record_unref(*rr);
+        *rr = new_rr;
+
+        return 1;
+}
+
+DnsTxtItem *dns_txt_item_free_all(DnsTxtItem *i) {
+        DnsTxtItem *n;
+
+        if (!i)
+                return NULL;
+
+        n = i->items_next;
+
+        free(i);
+        return dns_txt_item_free_all(n);
+}
+
+bool dns_txt_item_equal(DnsTxtItem *a, DnsTxtItem *b) {
+
+        if (a == b)
+                return true;
+
+        if (!a != !b)
+                return false;
+
+        if (!a)
+                return true;
+
+        if (a->length != b->length)
+                return false;
+
+        if (memcmp(a->data, b->data, a->length) != 0)
+                return false;
+
+        return dns_txt_item_equal(a->items_next, b->items_next);
+}
+
+DnsTxtItem *dns_txt_item_copy(DnsTxtItem *first) {
+        DnsTxtItem *i, *copy = NULL, *end = NULL;
+
+        LIST_FOREACH(items, i, first) {
+                DnsTxtItem *j;
+
+                j = memdup(i, offsetof(DnsTxtItem, data) + i->length + 1);
+                if (!j) {
+                        dns_txt_item_free_all(copy);
+                        return NULL;
+                }
+
+                LIST_INSERT_AFTER(items, copy, end, j);
+                end = j;
+        }
+
+        return copy;
+}
+
+static const char* const dnssec_algorithm_table[_DNSSEC_ALGORITHM_MAX_DEFINED] = {
+        /* Mnemonics as listed on https://www.iana.org/assignments/dns-sec-alg-numbers/dns-sec-alg-numbers.xhtml */
+        [DNSSEC_ALGORITHM_RSAMD5]             = "RSAMD5",
+        [DNSSEC_ALGORITHM_DH]                 = "DH",
+        [DNSSEC_ALGORITHM_DSA]                = "DSA",
+        [DNSSEC_ALGORITHM_ECC]                = "ECC",
+        [DNSSEC_ALGORITHM_RSASHA1]            = "RSASHA1",
+        [DNSSEC_ALGORITHM_DSA_NSEC3_SHA1]     = "DSA-NSEC3-SHA1",
+        [DNSSEC_ALGORITHM_RSASHA1_NSEC3_SHA1] = "RSASHA1-NSEC3-SHA1",
+        [DNSSEC_ALGORITHM_RSASHA256]          = "RSASHA256",
+        [DNSSEC_ALGORITHM_RSASHA512]          = "RSASHA512",
+        [DNSSEC_ALGORITHM_ECC_GOST]           = "ECC-GOST",
+        [DNSSEC_ALGORITHM_ECDSAP256SHA256]    = "ECDSAP256SHA256",
+        [DNSSEC_ALGORITHM_ECDSAP384SHA384]    = "ECDSAP384SHA384",
+        [DNSSEC_ALGORITHM_INDIRECT]           = "INDIRECT",
+        [DNSSEC_ALGORITHM_PRIVATEDNS]         = "PRIVATEDNS",
+        [DNSSEC_ALGORITHM_PRIVATEOID]         = "PRIVATEOID",
+};
+DEFINE_STRING_TABLE_LOOKUP_WITH_FALLBACK(dnssec_algorithm, int, 255);
+
+static const char* const dnssec_digest_table[_DNSSEC_DIGEST_MAX_DEFINED] = {
+        /* Names as listed on https://www.iana.org/assignments/ds-rr-types/ds-rr-types.xhtml */
+        [DNSSEC_DIGEST_SHA1] = "SHA-1",
+        [DNSSEC_DIGEST_SHA256] = "SHA-256",
+        [DNSSEC_DIGEST_GOST_R_34_11_94] = "GOST_R_34.11-94",
+        [DNSSEC_DIGEST_SHA384] = "SHA-384",
+};
+DEFINE_STRING_TABLE_LOOKUP_WITH_FALLBACK(dnssec_digest, int, 255);
diff --git a/src/grp-resolve/libbasic-dns/test/test-data/_443._tcp.fedoraproject.org.pkts b/src/grp-resolve/libbasic-dns/test/test-data/_443._tcp.fedoraproject.org.pkts
new file mode 100644
index 0000000000..a383c6286d
--- /dev/null
+++ b/src/grp-resolve/libbasic-dns/test/test-data/_443._tcp.fedoraproject.org.pkts
diff --git a/src/grp-resolve/libbasic-dns/test/test-data/_openpgpkey.fedoraproject.org.pkts b/src/grp-resolve/libbasic-dns/test/test-data/_openpgpkey.fedoraproject.org.pkts
new file mode 100644
index 0000000000..15de02e997
--- /dev/null
+++ b/src/grp-resolve/libbasic-dns/test/test-data/_openpgpkey.fedoraproject.org.pkts
diff --git a/src/grp-resolve/libbasic-dns/test/test-data/fake-caa.pkts b/src/grp-resolve/libbasic-dns/test/test-data/fake-caa.pkts
new file mode 100644
index 0000000000..1c3ecc5491
--- /dev/null
+++ b/src/grp-resolve/libbasic-dns/test/test-data/fake-caa.pkts
diff --git a/src/grp-resolve/libbasic-dns/test/test-data/fedoraproject.org.pkts b/src/grp-resolve/libbasic-dns/test/test-data/fedoraproject.org.pkts
new file mode 100644
index 0000000000..17874844d9
--- /dev/null
+++ b/src/grp-resolve/libbasic-dns/test/test-data/fedoraproject.org.pkts
diff --git a/src/grp-resolve/libbasic-dns/test/test-data/gandi.net.pkts b/src/grp-resolve/libbasic-dns/test/test-data/gandi.net.pkts
new file mode 100644
index 0000000000..5ef51e0c8e
--- /dev/null
+++ b/src/grp-resolve/libbasic-dns/test/test-data/gandi.net.pkts
diff --git a/src/grp-resolve/libbasic-dns/test/test-data/google.com.pkts b/src/grp-resolve/libbasic-dns/test/test-data/google.com.pkts
new file mode 100644
index 0000000000..f98c4cd855
--- /dev/null
+++ b/src/grp-resolve/libbasic-dns/test/test-data/google.com.pkts
diff --git a/src/grp-resolve/libbasic-dns/test/test-data/kyhwana.org.pkts b/src/grp-resolve/libbasic-dns/test/test-data/kyhwana.org.pkts
new file mode 100644
index 0000000000..e28a725c9a
--- /dev/null
+++ b/src/grp-resolve/libbasic-dns/test/test-data/kyhwana.org.pkts
diff --git a/src/grp-resolve/libbasic-dns/test/test-data/root.pkts b/src/grp-resolve/libbasic-dns/test/test-data/root.pkts
new file mode 100644
index 0000000000..54ba668c75
--- /dev/null
+++ b/src/grp-resolve/libbasic-dns/test/test-data/root.pkts
diff --git a/src/grp-resolve/libbasic-dns/test/test-data/sw1a1aa-sw1a2aa-sw1a2ab-sw1a2ac.find.me.uk.pkts b/src/grp-resolve/libbasic-dns/test/test-data/sw1a1aa-sw1a2aa-sw1a2ab-sw1a2ac.find.me.uk.pkts
new file mode 100644
index 0000000000..a854249532
--- /dev/null
+++ b/src/grp-resolve/libbasic-dns/test/test-data/sw1a1aa-sw1a2aa-sw1a2ab-sw1a2ac.find.me.uk.pkts
diff --git a/src/grp-resolve/libbasic-dns/test/test-data/teamits.com.pkts b/src/grp-resolve/libbasic-dns/test/test-data/teamits.com.pkts
new file mode 100644
index 0000000000..11deb39677
--- /dev/null
+++ b/src/grp-resolve/libbasic-dns/test/test-data/teamits.com.pkts
diff --git a/src/grp-resolve/libbasic-dns/test/test-data/zbyszek@fedoraproject.org.pkts b/src/grp-resolve/libbasic-dns/test/test-data/zbyszek@fedoraproject.org.pkts
new file mode 100644
index 0000000000..f0a6f982df
--- /dev/null
+++ b/src/grp-resolve/libbasic-dns/test/test-data/zbyszek@fedoraproject.org.pkts
diff --git a/src/grp-resolve/libbasic-dns/test/test-dns-packet.c b/src/grp-resolve/libbasic-dns/test/test-dns-packet.c
new file mode 100644
index 0000000000..7a012c13dd
--- /dev/null
+++ b/src/grp-resolve/libbasic-dns/test/test-dns-packet.c
@@ -0,0 +1,132 @@
+/***
+  This file is part of systemd
+
+  Copyright 2016 Zbigniew Jędrzejewski-Szmek
+
+  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 <glob.h>
+#include <net/if.h>
+
+#include "basic-dns/resolved-dns-packet.h"
+#include "basic-dns/resolved-dns-rr.h"
+#include "systemd-basic/alloc-util.h"
+#include "systemd-basic/fileio.h"
+#include "systemd-basic/glob-util.h"
+#include "systemd-basic/log.h"
+#include "systemd-basic/macro.h"
+#include "systemd-basic/string-util.h"
+#include "systemd-basic/strv.h"
+#include "systemd-basic/unaligned.h"
+
+#define HASH_KEY SD_ID128_MAKE(d3,1e,48,90,4b,fa,4c,fe,af,9d,d5,a1,d7,2e,8a,b1)
+
+static void verify_rr_copy(DnsResourceRecord *rr) {
+        _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *copy = NULL;
+        const char *a, *b;
+
+        assert_se(copy = dns_resource_record_copy(rr));
+        assert_se(dns_resource_record_equal(copy, rr) > 0);
+
+        assert_se(a = dns_resource_record_to_string(rr));
+        assert_se(b = dns_resource_record_to_string(copy));
+
+        assert_se(streq(a, b));
+}
+
+static uint64_t hash(DnsResourceRecord *rr) {
+        struct siphash state;
+
+        siphash24_init(&state, HASH_KEY.bytes);
+        dns_resource_record_hash_func(rr, &state);
+        return siphash24_finalize(&state);
+}
+
+static void test_packet_from_file(const char* filename, bool canonical) {
+        _cleanup_free_ char *data = NULL;
+        size_t data_size, packet_size, offset;
+
+        assert_se(read_full_file(filename, &data, &data_size) >= 0);
+        assert_se(data);
+        assert_se(data_size > 8);
+
+        log_info("============== %s %s==============", filename, canonical ? "canonical " : "");
+
+        for (offset = 0; offset < data_size; offset += 8 + packet_size) {
+                _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL, *p2 = NULL;
+                _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL, *rr2 = NULL;
+                const char *s, *s2;
+                uint64_t hash1, hash2;
+
+                packet_size = unaligned_read_le64(data + offset);
+                assert_se(packet_size > 0);
+                assert_se(offset + 8 + packet_size <= data_size);
+
+                assert_se(dns_packet_new(&p, DNS_PROTOCOL_DNS, 0) >= 0);
+
+                assert_se(dns_packet_append_blob(p, data + offset + 8, packet_size, NULL) >= 0);
+                assert_se(dns_packet_read_rr(p, &rr, NULL, NULL) >= 0);
+
+                verify_rr_copy(rr);
+
+                s = dns_resource_record_to_string(rr);
+                assert_se(s);
+                puts(s);
+
+                hash1 = hash(rr);
+
+                assert_se(dns_resource_record_to_wire_format(rr, canonical) >= 0);
+
+                assert_se(dns_packet_new(&p2, DNS_PROTOCOL_DNS, 0) >= 0);
+                assert_se(dns_packet_append_blob(p2, rr->wire_format, rr->wire_format_size, NULL) >= 0);
+                assert_se(dns_packet_read_rr(p2, &rr2, NULL, NULL) >= 0);
+
+                verify_rr_copy(rr);
+
+                s2 = dns_resource_record_to_string(rr);
+                assert_se(s2);
+                assert_se(streq(s, s2));
+
+                hash2 = hash(rr);
+                assert_se(hash1 == hash2);
+        }
+}
+
+int main(int argc, char **argv) {
+        int i, N;
+        _cleanup_globfree_ glob_t g = {};
+        char **fnames;
+
+        log_parse_environment();
+
+        if (argc >= 2) {
+                N = argc - 1;
+                fnames = argv + 1;
+        } else {
+                assert_se(glob(RESOLVE_TEST_DIR "/*.pkts", GLOB_NOSORT, NULL, &g) == 0);
+                N = g.gl_pathc;
+                fnames = g.gl_pathv;
+        }
+
+        for (i = 0; i < N; i++) {
+                test_packet_from_file(fnames[i], false);
+                puts("");
+                test_packet_from_file(fnames[i], true);
+                if (i + 1 < N)
+                        puts("");
+        }
+
+        return EXIT_SUCCESS;
+}
diff --git a/src/grp-resolve/libbasic-dns/test/test-dnssec-complex.c b/src/grp-resolve/libbasic-dns/test/test-dnssec-complex.c
new file mode 100644
index 0000000000..2eb4cfe1c2
--- /dev/null
+++ b/src/grp-resolve/libbasic-dns/test/test-dnssec-complex.c
@@ -0,0 +1,236 @@
+/***
+  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 <netinet/ip.h>
+
+#include <systemd/sd-bus.h>
+
+#include "basic-dns/dns-type.h"
+#include "sd-bus/bus-common-errors.h"
+#include "systemd-basic/af-list.h"
+#include "systemd-basic/alloc-util.h"
+#include "systemd-basic/random-util.h"
+#include "systemd-basic/string-util.h"
+#include "systemd-basic/time-util.h"
+
+#define DNS_CALL_TIMEOUT_USEC (45*USEC_PER_SEC)
+
+static void prefix_random(const char *name, char **ret) {
+        uint64_t i, u;
+        char *m = NULL;
+
+        u = 1 + (random_u64() & 3);
+
+        for (i = 0; i < u; i++) {
+                _cleanup_free_ char *b = NULL;
+                char *x;
+
+                assert_se(asprintf(&b, "x%" PRIu64 "x", random_u64()));
+                x = strjoin(b, ".", name, NULL);
+                assert_se(x);
+
+                free(m);
+                m = x;
+        }
+
+        *ret = m;
+ }
+
+static void test_rr_lookup(sd_bus *bus, const char *name, uint16_t type, const char *result) {
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *req = NULL, *reply = NULL;
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+        _cleanup_free_ char *m = NULL;
+        int r;
+
+        /* If the name starts with a dot, we prefix one to three random labels */
+        if (startswith(name, ".")) {
+                prefix_random(name + 1, &m);
+                name = m;
+        }
+
+        assert_se(sd_bus_message_new_method_call(
+                                  bus,
+                                  &req,
+                                  "org.freedesktop.resolve1",
+                                  "/org/freedesktop/resolve1",
+                                  "org.freedesktop.resolve1.Manager",
+                                  "ResolveRecord") >= 0);
+
+        assert_se(sd_bus_message_append(req, "isqqt", 0, name, DNS_CLASS_IN, type, UINT64_C(0)) >= 0);
+
+        r = sd_bus_call(bus, req, DNS_CALL_TIMEOUT_USEC, &error, &reply);
+
+        if (r < 0) {
+                assert_se(result);
+                assert_se(sd_bus_error_has_name(&error, result));
+                log_info("[OK] %s/%s resulted in <%s>.", name, dns_type_to_string(type), error.name);
+        } else {
+                assert_se(!result);
+                log_info("[OK] %s/%s succeeded.", name, dns_type_to_string(type));
+        }
+}
+
+static void test_hostname_lookup(sd_bus *bus, const char *name, int family, const char *result) {
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *req = NULL, *reply = NULL;
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+        _cleanup_free_ char *m = NULL;
+        const char *af;
+        int r;
+
+        af = family == AF_UNSPEC ? "AF_UNSPEC" : af_to_name(family);
+
+        /* If the name starts with a dot, we prefix one to three random labels */
+        if (startswith(name, ".")) {
+                prefix_random(name + 1, &m);
+                name = m;
+        }
+
+        assert_se(sd_bus_message_new_method_call(
+                                  bus,
+                                  &req,
+                                  "org.freedesktop.resolve1",
+                                  "/org/freedesktop/resolve1",
+                                  "org.freedesktop.resolve1.Manager",
+                                  "ResolveHostname") >= 0);
+
+        assert_se(sd_bus_message_append(req, "isit", 0, name, family, UINT64_C(0)) >= 0);
+
+        r = sd_bus_call(bus, req, DNS_CALL_TIMEOUT_USEC, &error, &reply);
+
+        if (r < 0) {
+                assert_se(result);
+                assert_se(sd_bus_error_has_name(&error, result));
+                log_info("[OK] %s/%s resulted in <%s>.", name, af, error.name);
+        } else {
+                assert_se(!result);
+                log_info("[OK] %s/%s succeeded.", name, af);
+        }
+
+}
+
+int main(int argc, char* argv[]) {
+        _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
+
+        /* Note that this is a manual test as it requires:
+         *
+         *    Full network access
+         *    A DNSSEC capable DNS server
+         *    That zones contacted are still set up as they were when I wrote this.
+         */
+
+        assert_se(sd_bus_open_system(&bus) >= 0);
+
+        /* Normally signed */
+        test_rr_lookup(bus, "www.eurid.eu", DNS_TYPE_A, NULL);
+        test_hostname_lookup(bus, "www.eurid.eu", AF_UNSPEC, NULL);
+
+        test_rr_lookup(bus, "sigok.verteiltesysteme.net", DNS_TYPE_A, NULL);
+        test_hostname_lookup(bus, "sigok.verteiltesysteme.net", AF_UNSPEC, NULL);
+
+        /* Normally signed, NODATA */
+        test_rr_lookup(bus, "www.eurid.eu", DNS_TYPE_RP, BUS_ERROR_NO_SUCH_RR);
+        test_rr_lookup(bus, "sigok.verteiltesysteme.net", DNS_TYPE_RP, BUS_ERROR_NO_SUCH_RR);
+
+        /* Invalid signature */
+        test_rr_lookup(bus, "sigfail.verteiltesysteme.net", DNS_TYPE_A, BUS_ERROR_DNSSEC_FAILED);
+        test_hostname_lookup(bus, "sigfail.verteiltesysteme.net", AF_INET, BUS_ERROR_DNSSEC_FAILED);
+
+        /* Invalid signature, RSA, wildcard */
+        test_rr_lookup(bus, ".wilda.rhybar.0skar.cz", DNS_TYPE_A, BUS_ERROR_DNSSEC_FAILED);
+        test_hostname_lookup(bus, ".wilda.rhybar.0skar.cz", AF_INET, BUS_ERROR_DNSSEC_FAILED);
+
+        /* Invalid signature, ECDSA, wildcard */
+        test_rr_lookup(bus, ".wilda.rhybar.ecdsa.0skar.cz", DNS_TYPE_A, BUS_ERROR_DNSSEC_FAILED);
+        test_hostname_lookup(bus, ".wilda.rhybar.ecdsa.0skar.cz", AF_INET, BUS_ERROR_DNSSEC_FAILED);
+
+        /* NXDOMAIN in NSEC domain */
+        test_rr_lookup(bus, "hhh.nasa.gov", DNS_TYPE_A, _BUS_ERROR_DNS "NXDOMAIN");
+        test_hostname_lookup(bus, "hhh.nasa.gov", AF_UNSPEC, _BUS_ERROR_DNS "NXDOMAIN");
+
+        /* wildcard, NSEC zone */
+        test_rr_lookup(bus, ".wilda.nsec.0skar.cz", DNS_TYPE_A, NULL);
+        test_hostname_lookup(bus, ".wilda.nsec.0skar.cz", AF_INET, NULL);
+
+        /* wildcard, NSEC zone, NODATA */
+        test_rr_lookup(bus, ".wilda.nsec.0skar.cz", DNS_TYPE_RP, BUS_ERROR_NO_SUCH_RR);
+
+        /* wildcard, NSEC3 zone */
+        test_rr_lookup(bus, ".wilda.0skar.cz", DNS_TYPE_A, NULL);
+        test_hostname_lookup(bus, ".wilda.0skar.cz", AF_INET, NULL);
+
+        /* wildcard, NSEC3 zone, NODATA */
+        test_rr_lookup(bus, ".wilda.0skar.cz", DNS_TYPE_RP, BUS_ERROR_NO_SUCH_RR);
+
+        /* wildcard, NSEC zone, CNAME */
+        test_rr_lookup(bus, ".wild.nsec.0skar.cz", DNS_TYPE_A, NULL);
+        test_hostname_lookup(bus, ".wild.nsec.0skar.cz", AF_UNSPEC, NULL);
+        test_hostname_lookup(bus, ".wild.nsec.0skar.cz", AF_INET, NULL);
+
+        /* wildcard, NSEC zone, NODATA, CNAME */
+        test_rr_lookup(bus, ".wild.nsec.0skar.cz", DNS_TYPE_RP, BUS_ERROR_NO_SUCH_RR);
+
+        /* wildcard, NSEC3 zone, CNAME */
+        test_rr_lookup(bus, ".wild.0skar.cz", DNS_TYPE_A, NULL);
+        test_hostname_lookup(bus, ".wild.0skar.cz", AF_UNSPEC, NULL);
+        test_hostname_lookup(bus, ".wild.0skar.cz", AF_INET, NULL);
+
+        /* wildcard, NSEC3 zone, NODATA, CNAME */
+        test_rr_lookup(bus, ".wild.0skar.cz", DNS_TYPE_RP, BUS_ERROR_NO_SUCH_RR);
+
+        /* NODATA due to empty non-terminal in NSEC domain */
+        test_rr_lookup(bus, "herndon.nasa.gov", DNS_TYPE_A, BUS_ERROR_NO_SUCH_RR);
+        test_hostname_lookup(bus, "herndon.nasa.gov", AF_UNSPEC, BUS_ERROR_NO_SUCH_RR);
+        test_hostname_lookup(bus, "herndon.nasa.gov", AF_INET, BUS_ERROR_NO_SUCH_RR);
+        test_hostname_lookup(bus, "herndon.nasa.gov", AF_INET6, BUS_ERROR_NO_SUCH_RR);
+
+        /* NXDOMAIN in NSEC root zone: */
+        test_rr_lookup(bus, "jasdhjas.kjkfgjhfjg", DNS_TYPE_A, _BUS_ERROR_DNS "NXDOMAIN");
+        test_hostname_lookup(bus, "jasdhjas.kjkfgjhfjg", AF_UNSPEC, _BUS_ERROR_DNS "NXDOMAIN");
+        test_hostname_lookup(bus, "jasdhjas.kjkfgjhfjg", AF_INET, _BUS_ERROR_DNS "NXDOMAIN");
+        test_hostname_lookup(bus, "jasdhjas.kjkfgjhfjg", AF_INET6, _BUS_ERROR_DNS "NXDOMAIN");
+
+        /* NXDOMAIN in NSEC3 .com zone: */
+        test_rr_lookup(bus, "kjkfgjhfjgsdfdsfd.com", DNS_TYPE_A, _BUS_ERROR_DNS "NXDOMAIN");
+        test_hostname_lookup(bus, "kjkfgjhfjgsdfdsfd.com", AF_INET, _BUS_ERROR_DNS "NXDOMAIN");
+        test_hostname_lookup(bus, "kjkfgjhfjgsdfdsfd.com", AF_INET6, _BUS_ERROR_DNS "NXDOMAIN");
+        test_hostname_lookup(bus, "kjkfgjhfjgsdfdsfd.com", AF_UNSPEC, _BUS_ERROR_DNS "NXDOMAIN");
+
+        /* Unsigned A */
+        test_rr_lookup(bus, "poettering.de", DNS_TYPE_A, NULL);
+        test_rr_lookup(bus, "poettering.de", DNS_TYPE_AAAA, NULL);
+        test_hostname_lookup(bus, "poettering.de", AF_UNSPEC, NULL);
+        test_hostname_lookup(bus, "poettering.de", AF_INET, NULL);
+        test_hostname_lookup(bus, "poettering.de", AF_INET6, NULL);
+
+#ifdef HAVE_LIBIDN
+        /* Unsigned A with IDNA conversion necessary */
+        test_hostname_lookup(bus, "pöttering.de", AF_UNSPEC, NULL);
+        test_hostname_lookup(bus, "pöttering.de", AF_INET, NULL);
+        test_hostname_lookup(bus, "pöttering.de", AF_INET6, NULL);
+#endif
+
+        /* DNAME, pointing to NXDOMAIN */
+        test_rr_lookup(bus, ".ireallyhpoethisdoesnexist.xn--kprw13d.", DNS_TYPE_A, _BUS_ERROR_DNS "NXDOMAIN");
+        test_rr_lookup(bus, ".ireallyhpoethisdoesnexist.xn--kprw13d.", DNS_TYPE_RP, _BUS_ERROR_DNS "NXDOMAIN");
+        test_hostname_lookup(bus, ".ireallyhpoethisdoesntexist.xn--kprw13d.", AF_UNSPEC, _BUS_ERROR_DNS "NXDOMAIN");
+        test_hostname_lookup(bus, ".ireallyhpoethisdoesntexist.xn--kprw13d.", AF_INET, _BUS_ERROR_DNS "NXDOMAIN");
+        test_hostname_lookup(bus, ".ireallyhpoethisdoesntexist.xn--kprw13d.", AF_INET6, _BUS_ERROR_DNS "NXDOMAIN");
+
+        return 0;
+}
diff --git a/src/grp-resolve/libbasic-dns/test/test-dnssec.c b/src/grp-resolve/libbasic-dns/test/test-dnssec.c
new file mode 100644
index 0000000000..c2b8a74944
--- /dev/null
+++ b/src/grp-resolve/libbasic-dns/test/test-dnssec.c
@@ -0,0 +1,343 @@
+/***
+  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 <arpa/inet.h>
+#include <netinet/in.h>
+#include <sys/socket.h>
+
+#include "basic-dns/resolved-dns-dnssec.h"
+#include "basic-dns/resolved-dns-rr.h"
+#include "systemd-basic/alloc-util.h"
+#include "systemd-basic/hexdecoct.h"
+#include "systemd-basic/string-util.h"
+
+static void test_dnssec_canonicalize_one(const char *original, const char *canonical, int r) {
+        char canonicalized[DNSSEC_CANONICAL_HOSTNAME_MAX];
+
+        assert_se(dnssec_canonicalize(original, canonicalized, sizeof(canonicalized)) == r);
+        if (r < 0)
+                return;
+
+        assert_se(streq(canonicalized, canonical));
+}
+
+static void test_dnssec_canonicalize(void) {
+        test_dnssec_canonicalize_one("", ".", 1);
+        test_dnssec_canonicalize_one(".", ".", 1);
+        test_dnssec_canonicalize_one("foo", "foo.", 4);
+        test_dnssec_canonicalize_one("foo.", "foo.", 4);
+        test_dnssec_canonicalize_one("FOO.", "foo.", 4);
+        test_dnssec_canonicalize_one("FOO.bar.", "foo.bar.", 8);
+        test_dnssec_canonicalize_one("FOO..bar.", NULL, -EINVAL);
+}
+
+#ifdef HAVE_GCRYPT
+
+static void test_dnssec_verify_dns_key(void) {
+
+        static const uint8_t ds1_fprint[] = {
+                0x46, 0x8B, 0xC8, 0xDD, 0xC7, 0xE8, 0x27, 0x03, 0x40, 0xBB, 0x8A, 0x1F, 0x3B, 0x2E, 0x45, 0x9D,
+                0x80, 0x67, 0x14, 0x01,
+        };
+        static const uint8_t ds2_fprint[] = {
+                0x8A, 0xEE, 0x80, 0x47, 0x05, 0x5F, 0x83, 0xD1, 0x48, 0xBA, 0x8F, 0xF6, 0xDD, 0xA7, 0x60, 0xCE,
+                0x94, 0xF7, 0xC7, 0x5E, 0x52, 0x4C, 0xF2, 0xE9, 0x50, 0xB9, 0x2E, 0xCB, 0xEF, 0x96, 0xB9, 0x98,
+        };
+        static const uint8_t dnskey_blob[] = {
+                0x03, 0x01, 0x00, 0x01, 0xa8, 0x12, 0xda, 0x4f, 0xd2, 0x7d, 0x54, 0x14, 0x0e, 0xcc, 0x5b, 0x5e,
+                0x45, 0x9c, 0x96, 0x98, 0xc0, 0xc0, 0x85, 0x81, 0xb1, 0x47, 0x8c, 0x7d, 0xe8, 0x39, 0x50, 0xcc,
+                0xc5, 0xd0, 0xf2, 0x00, 0x81, 0x67, 0x79, 0xf6, 0xcc, 0x9d, 0xad, 0x6c, 0xbb, 0x7b, 0x6f, 0x48,
+                0x97, 0x15, 0x1c, 0xfd, 0x0b, 0xfe, 0xd3, 0xd7, 0x7d, 0x9f, 0x81, 0x26, 0xd3, 0xc5, 0x65, 0x49,
+                0xcf, 0x46, 0x62, 0xb0, 0x55, 0x6e, 0x47, 0xc7, 0x30, 0xef, 0x51, 0xfb, 0x3e, 0xc6, 0xef, 0xde,
+                0x27, 0x3f, 0xfa, 0x57, 0x2d, 0xa7, 0x1d, 0x80, 0x46, 0x9a, 0x5f, 0x14, 0xb3, 0xb0, 0x2c, 0xbe,
+                0x72, 0xca, 0xdf, 0xb2, 0xff, 0x36, 0x5b, 0x4f, 0xec, 0x58, 0x8e, 0x8d, 0x01, 0xe9, 0xa9, 0xdf,
+                0xb5, 0x60, 0xad, 0x52, 0x4d, 0xfc, 0xa9, 0x3e, 0x8d, 0x35, 0x95, 0xb3, 0x4e, 0x0f, 0xca, 0x45,
+                0x1b, 0xf7, 0xef, 0x3a, 0x88, 0x25, 0x08, 0xc7, 0x4e, 0x06, 0xc1, 0x62, 0x1a, 0xce, 0xd8, 0x77,
+                0xbd, 0x02, 0x65, 0xf8, 0x49, 0xfb, 0xce, 0xf6, 0xa8, 0x09, 0xfc, 0xde, 0xb2, 0x09, 0x9d, 0x39,
+                0xf8, 0x63, 0x9c, 0x32, 0x42, 0x7c, 0xa0, 0x30, 0x86, 0x72, 0x7a, 0x4a, 0xc6, 0xd4, 0xb3, 0x2d,
+                0x24, 0xef, 0x96, 0x3f, 0xc2, 0xda, 0xd3, 0xf2, 0x15, 0x6f, 0xda, 0x65, 0x4b, 0x81, 0x28, 0x68,
+                0xf4, 0xfe, 0x3e, 0x71, 0x4f, 0x50, 0x96, 0x72, 0x58, 0xa1, 0x89, 0xdd, 0x01, 0x61, 0x39, 0x39,
+                0xc6, 0x76, 0xa4, 0xda, 0x02, 0x70, 0x3d, 0xc0, 0xdc, 0x8d, 0x70, 0x72, 0x04, 0x90, 0x79, 0xd4,
+                0xec, 0x65, 0xcf, 0x49, 0x35, 0x25, 0x3a, 0x14, 0x1a, 0x45, 0x20, 0xeb, 0x31, 0xaf, 0x92, 0xba,
+                0x20, 0xd3, 0xcd, 0xa7, 0x13, 0x44, 0xdc, 0xcf, 0xf0, 0x27, 0x34, 0xb9, 0xe7, 0x24, 0x6f, 0x73,
+                0xe7, 0xea, 0x77, 0x03,
+        };
+
+        _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *dnskey = NULL, *ds1 = NULL, *ds2 = NULL;
+
+        /* The two DS RRs in effect for nasa.gov on 2015-12-01. */
+        ds1 = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_DS, "nasa.gov");
+        assert_se(ds1);
+
+        ds1->ds.key_tag = 47857;
+        ds1->ds.algorithm = DNSSEC_ALGORITHM_RSASHA256;
+        ds1->ds.digest_type = DNSSEC_DIGEST_SHA1;
+        ds1->ds.digest_size = sizeof(ds1_fprint);
+        ds1->ds.digest = memdup(ds1_fprint, ds1->ds.digest_size);
+        assert_se(ds1->ds.digest);
+
+        log_info("DS1: %s", strna(dns_resource_record_to_string(ds1)));
+
+        ds2 = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_DS, "NASA.GOV");
+        assert_se(ds2);
+
+        ds2->ds.key_tag = 47857;
+        ds2->ds.algorithm = DNSSEC_ALGORITHM_RSASHA256;
+        ds2->ds.digest_type = DNSSEC_DIGEST_SHA256;
+        ds2->ds.digest_size = sizeof(ds2_fprint);
+        ds2->ds.digest = memdup(ds2_fprint, ds2->ds.digest_size);
+        assert_se(ds2->ds.digest);
+
+        log_info("DS2: %s", strna(dns_resource_record_to_string(ds2)));
+
+        dnskey = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_DNSKEY, "nasa.GOV");
+        assert_se(dnskey);
+
+        dnskey->dnskey.flags = 257;
+        dnskey->dnskey.protocol = 3;
+        dnskey->dnskey.algorithm = DNSSEC_ALGORITHM_RSASHA256;
+        dnskey->dnskey.key_size = sizeof(dnskey_blob);
+        dnskey->dnskey.key = memdup(dnskey_blob, sizeof(dnskey_blob));
+        assert_se(dnskey->dnskey.key);
+
+        log_info("DNSKEY: %s", strna(dns_resource_record_to_string(dnskey)));
+        log_info("DNSKEY keytag: %u", dnssec_keytag(dnskey, false));
+
+        assert_se(dnssec_verify_dnskey_by_ds(dnskey, ds1, false) > 0);
+        assert_se(dnssec_verify_dnskey_by_ds(dnskey, ds2, false) > 0);
+}
+
+static void test_dnssec_verify_rrset(void) {
+
+        static const uint8_t signature_blob[] = {
+                0x7f, 0x79, 0xdd, 0x5e, 0x89, 0x79, 0x18, 0xd0, 0x34, 0x86, 0x8c, 0x72, 0x77, 0x75, 0x48, 0x4d,
+                0xc3, 0x7d, 0x38, 0x04, 0xab, 0xcd, 0x9e, 0x4c, 0x82, 0xb0, 0x92, 0xca, 0xe9, 0x66, 0xe9, 0x6e,
+                0x47, 0xc7, 0x68, 0x8c, 0x94, 0xf6, 0x69, 0xcb, 0x75, 0x94, 0xe6, 0x30, 0xa6, 0xfb, 0x68, 0x64,
+                0x96, 0x1a, 0x84, 0xe1, 0xdc, 0x16, 0x4c, 0x83, 0x6c, 0x44, 0xf2, 0x74, 0x4d, 0x74, 0x79, 0x8f,
+                0xf3, 0xf4, 0x63, 0x0d, 0xef, 0x5a, 0xe7, 0xe2, 0xfd, 0xf2, 0x2b, 0x38, 0x7c, 0x28, 0x96, 0x9d,
+                0xb6, 0xcd, 0x5c, 0x3b, 0x57, 0xe2, 0x24, 0x78, 0x65, 0xd0, 0x9e, 0x77, 0x83, 0x09, 0x6c, 0xff,
+                0x3d, 0x52, 0x3f, 0x6e, 0xd1, 0xed, 0x2e, 0xf9, 0xee, 0x8e, 0xa6, 0xbe, 0x9a, 0xa8, 0x87, 0x76,
+                0xd8, 0x77, 0xcc, 0x96, 0xa0, 0x98, 0xa1, 0xd1, 0x68, 0x09, 0x43, 0xcf, 0x56, 0xd9, 0xd1, 0x66,
+        };
+
+        static const uint8_t dnskey_blob[] = {
+                0x03, 0x01, 0x00, 0x01, 0x9b, 0x49, 0x9b, 0xc1, 0xf9, 0x9a, 0xe0, 0x4e, 0xcf, 0xcb, 0x14, 0x45,
+                0x2e, 0xc9, 0xf9, 0x74, 0xa7, 0x18, 0xb5, 0xf3, 0xde, 0x39, 0x49, 0xdf, 0x63, 0x33, 0x97, 0x52,
+                0xe0, 0x8e, 0xac, 0x50, 0x30, 0x8e, 0x09, 0xd5, 0x24, 0x3d, 0x26, 0xa4, 0x49, 0x37, 0x2b, 0xb0,
+                0x6b, 0x1b, 0xdf, 0xde, 0x85, 0x83, 0xcb, 0x22, 0x4e, 0x60, 0x0a, 0x91, 0x1a, 0x1f, 0xc5, 0x40,
+                0xb1, 0xc3, 0x15, 0xc1, 0x54, 0x77, 0x86, 0x65, 0x53, 0xec, 0x10, 0x90, 0x0c, 0x91, 0x00, 0x5e,
+                0x15, 0xdc, 0x08, 0x02, 0x4c, 0x8c, 0x0d, 0xc0, 0xac, 0x6e, 0xc4, 0x3e, 0x1b, 0x80, 0x19, 0xe4,
+                0xf7, 0x5f, 0x77, 0x51, 0x06, 0x87, 0x61, 0xde, 0xa2, 0x18, 0x0f, 0x40, 0x8b, 0x79, 0x72, 0xfa,
+                0x8d, 0x1a, 0x44, 0x47, 0x0d, 0x8e, 0x3a, 0x2d, 0xc7, 0x39, 0xbf, 0x56, 0x28, 0x97, 0xd9, 0x20,
+                0x4f, 0x00, 0x51, 0x3b,
+        };
+
+        _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *a = NULL, *rrsig = NULL, *dnskey = NULL;
+        _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
+        DnssecResult result;
+
+        a = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_A, "nAsA.gov");
+        assert_se(a);
+
+        a->a.in_addr.s_addr = inet_addr("52.0.14.116");
+
+        log_info("A: %s", strna(dns_resource_record_to_string(a)));
+
+        rrsig = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_RRSIG, "NaSa.GOV.");
+        assert_se(rrsig);
+
+        rrsig->rrsig.type_covered = DNS_TYPE_A;
+        rrsig->rrsig.algorithm = DNSSEC_ALGORITHM_RSASHA256;
+        rrsig->rrsig.labels = 2;
+        rrsig->rrsig.original_ttl = 600;
+        rrsig->rrsig.expiration = 0x5683135c;
+        rrsig->rrsig.inception = 0x565b7da8;
+        rrsig->rrsig.key_tag = 63876;
+        rrsig->rrsig.signer = strdup("Nasa.Gov.");
+        assert_se(rrsig->rrsig.signer);
+        rrsig->rrsig.signature_size = sizeof(signature_blob);
+        rrsig->rrsig.signature = memdup(signature_blob, rrsig->rrsig.signature_size);
+        assert_se(rrsig->rrsig.signature);
+
+        log_info("RRSIG: %s", strna(dns_resource_record_to_string(rrsig)));
+
+        dnskey = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_DNSKEY, "nASA.gOV");
+        assert_se(dnskey);
+
+        dnskey->dnskey.flags = 256;
+        dnskey->dnskey.protocol = 3;
+        dnskey->dnskey.algorithm = DNSSEC_ALGORITHM_RSASHA256;
+        dnskey->dnskey.key_size = sizeof(dnskey_blob);
+        dnskey->dnskey.key = memdup(dnskey_blob, sizeof(dnskey_blob));
+        assert_se(dnskey->dnskey.key);
+
+        log_info("DNSKEY: %s", strna(dns_resource_record_to_string(dnskey)));
+        log_info("DNSKEY keytag: %u", dnssec_keytag(dnskey, false));
+
+        assert_se(dnssec_key_match_rrsig(a->key, rrsig) > 0);
+        assert_se(dnssec_rrsig_match_dnskey(rrsig, dnskey, false) > 0);
+
+        answer = dns_answer_new(1);
+        assert_se(answer);
+        assert_se(dns_answer_add(answer, a, 0, DNS_ANSWER_AUTHENTICATED) >= 0);
+
+        /* Validate the RR as it if was 2015-12-2 today */
+        assert_se(dnssec_verify_rrset(answer, a->key, rrsig, dnskey, 1449092754*USEC_PER_SEC, &result) >= 0);
+        assert_se(result == DNSSEC_VALIDATED);
+}
+
+static void test_dnssec_verify_rrset2(void) {
+
+        static const uint8_t signature_blob[] = {
+                0x48, 0x45, 0xc8, 0x8b, 0xc0, 0x14, 0x92, 0xf5, 0x15, 0xc6, 0x84, 0x9d, 0x2f, 0xe3, 0x32, 0x11,
+                0x7d, 0xf1, 0xe6, 0x87, 0xb9, 0x42, 0xd3, 0x8b, 0x9e, 0xaf, 0x92, 0x31, 0x0a, 0x53, 0xad, 0x8b,
+                0xa7, 0x5c, 0x83, 0x39, 0x8c, 0x28, 0xac, 0xce, 0x6e, 0x9c, 0x18, 0xe3, 0x31, 0x16, 0x6e, 0xca,
+                0x38, 0x31, 0xaf, 0xd9, 0x94, 0xf1, 0x84, 0xb1, 0xdf, 0x5a, 0xc2, 0x73, 0x22, 0xf6, 0xcb, 0xa2,
+                0xe7, 0x8c, 0x77, 0x0c, 0x74, 0x2f, 0xc2, 0x13, 0xb0, 0x93, 0x51, 0xa9, 0x4f, 0xae, 0x0a, 0xda,
+                0x45, 0xcc, 0xfd, 0x43, 0x99, 0x36, 0x9a, 0x0d, 0x21, 0xe0, 0xeb, 0x30, 0x65, 0xd4, 0xa0, 0x27,
+                0x37, 0x3b, 0xe4, 0xc1, 0xc5, 0xa1, 0x2a, 0xd1, 0x76, 0xc4, 0x7e, 0x64, 0x0e, 0x5a, 0xa6, 0x50,
+                0x24, 0xd5, 0x2c, 0xcc, 0x6d, 0xe5, 0x37, 0xea, 0xbd, 0x09, 0x34, 0xed, 0x24, 0x06, 0xa1, 0x22,
+        };
+
+        static const uint8_t dnskey_blob[] = {
+                0x03, 0x01, 0x00, 0x01, 0xc3, 0x7f, 0x1d, 0xd1, 0x1c, 0x97, 0xb1, 0x13, 0x34, 0x3a, 0x9a, 0xea,
+                0xee, 0xd9, 0x5a, 0x11, 0x1b, 0x17, 0xc7, 0xe3, 0xd4, 0xda, 0x20, 0xbc, 0x5d, 0xba, 0x74, 0xe3,
+                0x37, 0x99, 0xec, 0x25, 0xce, 0x93, 0x7f, 0xbd, 0x22, 0x73, 0x7e, 0x14, 0x71, 0xe0, 0x60, 0x07,
+                0xd4, 0x39, 0x8b, 0x5e, 0xe9, 0xba, 0x25, 0xe8, 0x49, 0xe9, 0x34, 0xef, 0xfe, 0x04, 0x5c, 0xa5,
+                0x27, 0xcd, 0xa9, 0xda, 0x70, 0x05, 0x21, 0xab, 0x15, 0x82, 0x24, 0xc3, 0x94, 0xf5, 0xd7, 0xb7,
+                0xc4, 0x66, 0xcb, 0x32, 0x6e, 0x60, 0x2b, 0x55, 0x59, 0x28, 0x89, 0x8a, 0x72, 0xde, 0x88, 0x56,
+                0x27, 0x95, 0xd9, 0xac, 0x88, 0x4f, 0x65, 0x2b, 0x68, 0xfc, 0xe6, 0x41, 0xc1, 0x1b, 0xef, 0x4e,
+                0xd6, 0xc2, 0x0f, 0x64, 0x88, 0x95, 0x5e, 0xdd, 0x3a, 0x02, 0x07, 0x50, 0xa9, 0xda, 0xa4, 0x49,
+                0x74, 0x62, 0xfe, 0xd7,
+        };
+
+        _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *nsec = NULL, *rrsig = NULL, *dnskey = NULL;
+        _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
+        DnssecResult result;
+
+        nsec = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_NSEC, "nasa.gov");
+        assert_se(nsec);
+
+        nsec->nsec.next_domain_name = strdup("3D-Printing.nasa.gov");
+        assert_se(nsec->nsec.next_domain_name);
+
+        nsec->nsec.types = bitmap_new();
+        assert_se(nsec->nsec.types);
+        assert_se(bitmap_set(nsec->nsec.types, DNS_TYPE_A) >= 0);
+        assert_se(bitmap_set(nsec->nsec.types, DNS_TYPE_NS) >= 0);
+        assert_se(bitmap_set(nsec->nsec.types, DNS_TYPE_SOA) >= 0);
+        assert_se(bitmap_set(nsec->nsec.types, DNS_TYPE_MX) >= 0);
+        assert_se(bitmap_set(nsec->nsec.types, DNS_TYPE_TXT) >= 0);
+        assert_se(bitmap_set(nsec->nsec.types, DNS_TYPE_RRSIG) >= 0);
+        assert_se(bitmap_set(nsec->nsec.types, DNS_TYPE_NSEC) >= 0);
+        assert_se(bitmap_set(nsec->nsec.types, DNS_TYPE_DNSKEY) >= 0);
+        assert_se(bitmap_set(nsec->nsec.types, 65534) >= 0);
+
+        log_info("NSEC: %s", strna(dns_resource_record_to_string(nsec)));
+
+        rrsig = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_RRSIG, "NaSa.GOV.");
+        assert_se(rrsig);
+
+        rrsig->rrsig.type_covered = DNS_TYPE_NSEC;
+        rrsig->rrsig.algorithm = DNSSEC_ALGORITHM_RSASHA256;
+        rrsig->rrsig.labels = 2;
+        rrsig->rrsig.original_ttl = 300;
+        rrsig->rrsig.expiration = 0x5689002f;
+        rrsig->rrsig.inception = 0x56617230;
+        rrsig->rrsig.key_tag = 30390;
+        rrsig->rrsig.signer = strdup("Nasa.Gov.");
+        assert_se(rrsig->rrsig.signer);
+        rrsig->rrsig.signature_size = sizeof(signature_blob);
+        rrsig->rrsig.signature = memdup(signature_blob, rrsig->rrsig.signature_size);
+        assert_se(rrsig->rrsig.signature);
+
+        log_info("RRSIG: %s", strna(dns_resource_record_to_string(rrsig)));
+
+        dnskey = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_DNSKEY, "nASA.gOV");
+        assert_se(dnskey);
+
+        dnskey->dnskey.flags = 256;
+        dnskey->dnskey.protocol = 3;
+        dnskey->dnskey.algorithm = DNSSEC_ALGORITHM_RSASHA256;
+        dnskey->dnskey.key_size = sizeof(dnskey_blob);
+        dnskey->dnskey.key = memdup(dnskey_blob, sizeof(dnskey_blob));
+        assert_se(dnskey->dnskey.key);
+
+        log_info("DNSKEY: %s", strna(dns_resource_record_to_string(dnskey)));
+        log_info("DNSKEY keytag: %u", dnssec_keytag(dnskey, false));
+
+        assert_se(dnssec_key_match_rrsig(nsec->key, rrsig) > 0);
+        assert_se(dnssec_rrsig_match_dnskey(rrsig, dnskey, false) > 0);
+
+        answer = dns_answer_new(1);
+        assert_se(answer);
+        assert_se(dns_answer_add(answer, nsec, 0, DNS_ANSWER_AUTHENTICATED) >= 0);
+
+        /* Validate the RR as it if was 2015-12-11 today */
+        assert_se(dnssec_verify_rrset(answer, nsec->key, rrsig, dnskey, 1449849318*USEC_PER_SEC, &result) >= 0);
+        assert_se(result == DNSSEC_VALIDATED);
+}
+
+static void test_dnssec_nsec3_hash(void) {
+        static const uint8_t salt[] = { 0xB0, 0x1D, 0xFA, 0xCE };
+        static const uint8_t next_hashed_name[] = { 0x84, 0x10, 0x26, 0x53, 0xc9, 0xfa, 0x4d, 0x85, 0x6c, 0x97, 0x82, 0xe2, 0x8f, 0xdf, 0x2d, 0x5e, 0x87, 0x69, 0xc4, 0x52 };
+        _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
+        uint8_t h[DNSSEC_HASH_SIZE_MAX];
+        _cleanup_free_ char *b = NULL;
+        int k;
+
+        /* The NSEC3 RR for eurid.eu on 2015-12-14. */
+        rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_NSEC3, "PJ8S08RR45VIQDAQGE7EN3VHKNROTBMM.eurid.eu.");
+        assert_se(rr);
+
+        rr->nsec3.algorithm = DNSSEC_DIGEST_SHA1;
+        rr->nsec3.flags = 1;
+        rr->nsec3.iterations = 1;
+        rr->nsec3.salt = memdup(salt, sizeof(salt));
+        assert_se(rr->nsec3.salt);
+        rr->nsec3.salt_size = sizeof(salt);
+        rr->nsec3.next_hashed_name = memdup(next_hashed_name, sizeof(next_hashed_name));
+        assert_se(rr->nsec3.next_hashed_name);
+        rr->nsec3.next_hashed_name_size = sizeof(next_hashed_name);
+
+        log_info("NSEC3: %s", strna(dns_resource_record_to_string(rr)));
+
+        k = dnssec_nsec3_hash(rr, "eurid.eu", &h);
+        assert_se(k >= 0);
+
+        b = base32hexmem(h, k, false);
+        assert_se(b);
+        assert_se(strcasecmp(b, "PJ8S08RR45VIQDAQGE7EN3VHKNROTBMM") == 0);
+}
+
+#endif
+
+int main(int argc, char*argv[]) {
+
+        test_dnssec_canonicalize();
+
+#ifdef HAVE_GCRYPT
+        test_dnssec_verify_dns_key();
+        test_dnssec_verify_rrset();
+        test_dnssec_verify_rrset2();
+        test_dnssec_nsec3_hash();
+#endif
+
+        return 0;
+}
diff --git a/src/grp-resolve/libbasic-dns/test/test-resolve-tables.c b/src/grp-resolve/libbasic-dns/test/test-resolve-tables.c
new file mode 100644
index 0000000000..98474b1abf
--- /dev/null
+++ b/src/grp-resolve/libbasic-dns/test/test-resolve-tables.c
@@ -0,0 +1,64 @@
+/***
+  This file is part of systemd
+
+  Copyright 2013 Zbigniew Jędrzejewski-Szmek
+
+  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 "systemd-shared/test-tables.h"
+
+int main(int argc, char **argv) {
+        uint16_t i;
+
+        test_table_sparse(dns_type, DNS_TYPE);
+
+        log_info("/* DNS_TYPE */");
+        for (i = 0; i < _DNS_TYPE_MAX; i++) {
+                const char *s;
+
+                s = dns_type_to_string(i);
+                assert_se(s == NULL || strlen(s) < _DNS_TYPE_STRING_MAX);
+
+                if (s)
+                        log_info("%-*s %s%s%s%s%s%s%s%s%s",
+                                 (int) _DNS_TYPE_STRING_MAX - 1, s,
+                                 dns_type_is_pseudo(i) ? "pseudo " : "",
+                                 dns_type_is_valid_query(i) ? "valid_query " : "",
+                                 dns_type_is_valid_rr(i) ? "is_valid_rr " : "",
+                                 dns_type_may_redirect(i) ? "may_redirect " : "",
+                                 dns_type_is_dnssec(i) ? "dnssec " : "",
+                                 dns_type_is_obsolete(i) ? "obsolete " : "",
+                                 dns_type_may_wildcard(i) ? "wildcard " : "",
+                                 dns_type_apex_only(i) ? "apex_only " : "",
+                                 dns_type_needs_authentication(i) ? "needs_authentication" : "");
+        }
+
+        log_info("/* DNS_CLASS */");
+        for (i = 0; i < _DNS_CLASS_MAX; i++) {
+                const char *s;
+
+                s = dns_class_to_string(i);
+                assert_se(s == NULL || strlen(s) < _DNS_CLASS_STRING_MAX);
+
+                if (s)
+                        log_info("%-*s %s%s",
+                                 (int) _DNS_CLASS_STRING_MAX - 1, s,
+                                 dns_class_is_pseudo(i) ? "is_pseudo " : "",
+                                 dns_class_is_valid_rr(i) ? "is_valid_rr " : "");
+        }
+
+        return EXIT_SUCCESS;
+}