/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ /*** This file is part of systemd. Copyright 2014 Tom Gundersen <teg@jklm.no> systemd is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. systemd is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with systemd; If not, see <http://www.gnu.org/licenses/>. ***/ #include <arpa/inet.h> #include <resolv.h> #include <net/if.h> #include <sys/ioctl.h> #include <sys/poll.h> #include <netinet/in.h> #include "rtnl-util.h" #include "event-util.h" #include "network-util.h" #include "network-internal.h" #include "conf-parser.h" #include "socket-util.h" #include "af-list.h" #include "utf8.h" #include "fileio-label.h" #include "resolved-dns-domain.h" #include "resolved-conf.h" #include "resolved-bus.h" #include "resolved-manager.h" #define SEND_TIMEOUT_USEC (200 * USEC_PER_MSEC) static int manager_process_link(sd_rtnl *rtnl, sd_rtnl_message *mm, void *userdata) { Manager *m = userdata; uint16_t type; Link *l; int ifindex, r; assert(rtnl); assert(m); assert(mm); r = sd_rtnl_message_get_type(mm, &type); if (r < 0) goto fail; r = sd_rtnl_message_link_get_ifindex(mm, &ifindex); if (r < 0) goto fail; l = hashmap_get(m->links, INT_TO_PTR(ifindex)); switch (type) { case RTM_NEWLINK:{ bool is_new = !l; if (!l) { r = link_new(m, &l, ifindex); if (r < 0) goto fail; } r = link_update_rtnl(l, mm); if (r < 0) goto fail; r = link_update_monitor(l); if (r < 0) goto fail; if (is_new) log_debug("Found new link %i/%s", ifindex, l->name); break; } case RTM_DELLINK: if (l) { log_debug("Removing link %i/%s", l->ifindex, l->name); link_free(l); } break; } return 0; fail: log_warning_errno(r, "Failed to process RTNL link message: %m"); return 0; } static int manager_process_address(sd_rtnl *rtnl, sd_rtnl_message *mm, void *userdata) { Manager *m = userdata; union in_addr_union address; uint16_t type; int r, ifindex, family; LinkAddress *a; Link *l; assert(rtnl); assert(mm); assert(m); r = sd_rtnl_message_get_type(mm, &type); if (r < 0) goto fail; r = sd_rtnl_message_addr_get_ifindex(mm, &ifindex); if (r < 0) goto fail; l = hashmap_get(m->links, INT_TO_PTR(ifindex)); if (!l) return 0; r = sd_rtnl_message_addr_get_family(mm, &family); if (r < 0) goto fail; switch (family) { case AF_INET: r = sd_rtnl_message_read_in_addr(mm, IFA_LOCAL, &address.in); if (r < 0) { r = sd_rtnl_message_read_in_addr(mm, IFA_ADDRESS, &address.in); if (r < 0) goto fail; } break; case AF_INET6: r = sd_rtnl_message_read_in6_addr(mm, IFA_LOCAL, &address.in6); if (r < 0) { r = sd_rtnl_message_read_in6_addr(mm, IFA_ADDRESS, &address.in6); if (r < 0) goto fail; } break; default: return 0; } a = link_find_address(l, family, &address); switch (type) { case RTM_NEWADDR: if (!a) { r = link_address_new(l, &a, family, &address); if (r < 0) return r; } r = link_address_update_rtnl(a, mm); if (r < 0) return r; break; case RTM_DELADDR: if (a) link_address_free(a); break; } return 0; fail: log_warning_errno(r, "Failed to process RTNL address message: %m"); return 0; } static int manager_rtnl_listen(Manager *m) { _cleanup_rtnl_message_unref_ sd_rtnl_message *req = NULL, *reply = NULL; sd_rtnl_message *i; int r; assert(m); /* First, subscibe to interfaces coming and going */ r = sd_rtnl_open(&m->rtnl, 3, RTNLGRP_LINK, RTNLGRP_IPV4_IFADDR, RTNLGRP_IPV6_IFADDR); if (r < 0) return r; r = sd_rtnl_attach_event(m->rtnl, m->event, 0); if (r < 0) return r; r = sd_rtnl_add_match(m->rtnl, RTM_NEWLINK, manager_process_link, m); if (r < 0) return r; r = sd_rtnl_add_match(m->rtnl, RTM_DELLINK, manager_process_link, m); if (r < 0) return r; r = sd_rtnl_add_match(m->rtnl, RTM_NEWADDR, manager_process_address, m); if (r < 0) return r; r = sd_rtnl_add_match(m->rtnl, RTM_DELADDR, manager_process_address, m); if (r < 0) return r; /* Then, enumerate all links */ r = sd_rtnl_message_new_link(m->rtnl, &req, RTM_GETLINK, 0); if (r < 0) return r; r = sd_rtnl_message_request_dump(req, true); if (r < 0) return r; r = sd_rtnl_call(m->rtnl, req, 0, &reply); if (r < 0) return r; for (i = reply; i; i = sd_rtnl_message_next(i)) { r = manager_process_link(m->rtnl, i, m); if (r < 0) return r; } req = sd_rtnl_message_unref(req); reply = sd_rtnl_message_unref(reply); /* Finally, enumerate all addresses, too */ r = sd_rtnl_message_new_addr(m->rtnl, &req, RTM_GETADDR, 0, AF_UNSPEC); if (r < 0) return r; r = sd_rtnl_message_request_dump(req, true); if (r < 0) return r; r = sd_rtnl_call(m->rtnl, req, 0, &reply); if (r < 0) return r; for (i = reply; i; i = sd_rtnl_message_next(i)) { r = manager_process_address(m->rtnl, i, m); if (r < 0) return r; } return r; } static int on_network_event(sd_event_source *s, int fd, uint32_t revents, void *userdata) { Manager *m = userdata; Iterator i; Link *l; int r; assert(m); sd_network_monitor_flush(m->network_monitor); HASHMAP_FOREACH(l, m->links, i) { r = link_update_monitor(l); if (r < 0) log_warning_errno(r, "Failed to update monitor information for %i: %m", l->ifindex); } r = manager_write_resolv_conf(m); if (r < 0) log_warning_errno(r, "Could not update resolv.conf: %m"); return 0; } static int manager_network_monitor_listen(Manager *m) { int r, fd, events; assert(m); r = sd_network_monitor_new(&m->network_monitor, NULL); if (r < 0) return r; fd = sd_network_monitor_get_fd(m->network_monitor); if (fd < 0) return fd; events = sd_network_monitor_get_events(m->network_monitor); if (events < 0) return events; r = sd_event_add_io(m->event, &m->network_event_source, fd, events, &on_network_event, m); if (r < 0) return r; return 0; } static int determine_hostname(char **ret) { _cleanup_free_ char *h = NULL, *n = NULL; int r; assert(ret); h = gethostname_malloc(); if (!h) return log_oom(); if (!utf8_is_valid(h)) { log_error("System hostname is not UTF-8 clean."); return -EINVAL; } r = dns_name_normalize(h, &n); if (r < 0) { log_error("System hostname '%s' cannot be normalized.", h); return r; } *ret = n; n = NULL; return 0; } static int on_hostname_change(sd_event_source *es, int fd, uint32_t revents, void *userdata) { _cleanup_free_ char *h = NULL; Manager *m = userdata; int r; assert(m); r = determine_hostname(&h); if (r < 0) return 0; /* ignore invalid hostnames */ if (streq(h, m->hostname)) return 0; log_info("System hostname changed to '%s'.", h); free(m->hostname); m->hostname = h; h = NULL; manager_refresh_rrs(m); return 0; } static int manager_watch_hostname(Manager *m) { int r; assert(m); m->hostname_fd = open("/proc/sys/kernel/hostname", O_RDONLY|O_CLOEXEC|O_NDELAY|O_NOCTTY); if (m->hostname_fd < 0) { log_warning_errno(errno, "Failed to watch hostname: %m"); return 0; } r = sd_event_add_io(m->event, &m->hostname_event_source, m->hostname_fd, 0, on_hostname_change, m); if (r < 0) { if (r == -EPERM) /* kernels prior to 3.2 don't support polling this file. Ignore the failure. */ m->hostname_fd = safe_close(m->hostname_fd); else return log_error_errno(r, "Failed to add hostname event source: %m"); } r = determine_hostname(&m->hostname); if (r < 0) { log_info("Defaulting to hostname 'linux'."); m->hostname = strdup("linux"); if (!m->hostname) return log_oom(); } else log_info("Using system hostname '%s'.", m->hostname); return 0; } static void manager_llmnr_stop(Manager *m) { assert(m); m->llmnr_ipv4_udp_event_source = sd_event_source_unref(m->llmnr_ipv4_udp_event_source); m->llmnr_ipv4_udp_fd = safe_close(m->llmnr_ipv4_udp_fd); m->llmnr_ipv6_udp_event_source = sd_event_source_unref(m->llmnr_ipv6_udp_event_source); m->llmnr_ipv6_udp_fd = safe_close(m->llmnr_ipv6_udp_fd); m->llmnr_ipv4_tcp_event_source = sd_event_source_unref(m->llmnr_ipv4_tcp_event_source); m->llmnr_ipv4_tcp_fd = safe_close(m->llmnr_ipv4_tcp_fd); m->llmnr_ipv6_tcp_event_source = sd_event_source_unref(m->llmnr_ipv6_tcp_event_source); m->llmnr_ipv6_tcp_fd = safe_close(m->llmnr_ipv6_tcp_fd); } static int manager_llmnr_start(Manager *m) { int r; assert(m); if (m->llmnr_support == SUPPORT_NO) return 0; r = manager_llmnr_ipv4_udp_fd(m); if (r == -EADDRINUSE) goto eaddrinuse; if (r < 0) return r; r = manager_llmnr_ipv4_tcp_fd(m); if (r == -EADDRINUSE) goto eaddrinuse; if (r < 0) return r; if (socket_ipv6_is_supported()) { r = manager_llmnr_ipv6_udp_fd(m); if (r == -EADDRINUSE) goto eaddrinuse; if (r < 0) return r; r = manager_llmnr_ipv6_tcp_fd(m); if (r == -EADDRINUSE) goto eaddrinuse; if (r < 0) return r; } return 0; eaddrinuse: log_warning("There appears to be another LLMNR responder running. Turning off LLMNR support."); m->llmnr_support = SUPPORT_NO; manager_llmnr_stop(m); return 0; } int manager_new(Manager **ret) { _cleanup_(manager_freep) Manager *m = NULL; int r; assert(ret); m = new0(Manager, 1); if (!m) return -ENOMEM; m->dns_ipv4_fd = m->dns_ipv6_fd = -1; m->llmnr_ipv4_udp_fd = m->llmnr_ipv6_udp_fd = -1; m->llmnr_ipv4_tcp_fd = m->llmnr_ipv6_tcp_fd = -1; m->hostname_fd = -1; m->llmnr_support = SUPPORT_YES; m->read_resolv_conf = true; r = manager_parse_dns_server(m, DNS_SERVER_FALLBACK, DNS_SERVERS); if (r < 0) return r; r = sd_event_default(&m->event); if (r < 0) return r; sd_event_add_signal(m->event, NULL, SIGTERM, NULL, NULL); sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL); sd_event_set_watchdog(m->event, true); r = manager_watch_hostname(m); if (r < 0) return r; r = dns_scope_new(m, &m->unicast_scope, NULL, DNS_PROTOCOL_DNS, AF_UNSPEC); if (r < 0) return r; r = manager_network_monitor_listen(m); if (r < 0) return r; r = manager_rtnl_listen(m); if (r < 0) return r; r = manager_connect_bus(m); if (r < 0) return r; *ret = m; m = NULL; return 0; } int manager_start(Manager *m) { int r; assert(m); r = manager_llmnr_start(m); if (r < 0) return r; return 0; } Manager *manager_free(Manager *m) { Link *l; if (!m) return NULL; while ((l = hashmap_first(m->links))) link_free(l); while (m->dns_queries) dns_query_free(m->dns_queries); dns_scope_free(m->unicast_scope); manager_flush_dns_servers(m, DNS_SERVER_SYSTEM); manager_flush_dns_servers(m, DNS_SERVER_FALLBACK); hashmap_free(m->links); hashmap_free(m->dns_transactions); sd_event_source_unref(m->network_event_source); sd_network_monitor_unref(m->network_monitor); sd_event_source_unref(m->dns_ipv4_event_source); sd_event_source_unref(m->dns_ipv6_event_source); safe_close(m->dns_ipv4_fd); safe_close(m->dns_ipv6_fd); manager_llmnr_stop(m); sd_bus_slot_unref(m->prepare_for_sleep_slot); sd_event_source_unref(m->bus_retry_event_source); sd_bus_unref(m->bus); sd_event_unref(m->event); dns_resource_key_unref(m->host_ipv4_key); dns_resource_key_unref(m->host_ipv6_key); safe_close(m->hostname_fd); sd_event_source_unref(m->hostname_event_source); free(m->hostname); free(m); return NULL; } int manager_read_resolv_conf(Manager *m) { _cleanup_fclose_ FILE *f = NULL; struct stat st, own; char line[LINE_MAX]; DnsServer *s, *nx; usec_t t; int r; assert(m); /* Reads the system /etc/resolv.conf, if it exists and is not * symlinked to our own resolv.conf instance */ if (!m->read_resolv_conf) return 0; r = stat("/etc/resolv.conf", &st); if (r < 0) { if (errno != ENOENT) log_warning_errno(errno, "Failed to open /etc/resolv.conf: %m"); r = -errno; goto clear; } /* Have we already seen the file? */ t = timespec_load(&st.st_mtim); if (t == m->resolv_conf_mtime) return 0; m->resolv_conf_mtime = t; /* Is it symlinked to our own file? */ if (stat("/run/systemd/resolve/resolv.conf", &own) >= 0 && st.st_dev == own.st_dev && st.st_ino == own.st_ino) { r = 0; goto clear; } f = fopen("/etc/resolv.conf", "re"); if (!f) { if (errno != ENOENT) log_warning_errno(errno, "Failed to open /etc/resolv.conf: %m"); r = -errno; goto clear; } if (fstat(fileno(f), &st) < 0) { log_error_errno(errno, "Failed to stat open file: %m"); r = -errno; goto clear; } LIST_FOREACH(servers, s, m->dns_servers) s->marked = true; FOREACH_LINE(line, f, r = -errno; goto clear) { union in_addr_union address; int family; char *l; const char *a; truncate_nl(line); l = strstrip(line); if (*l == '#' || *l == ';') continue; a = first_word(l, "nameserver"); if (!a) continue; r = in_addr_from_string_auto(a, &family, &address); if (r < 0) { log_warning("Failed to parse name server %s.", a); continue; } LIST_FOREACH(servers, s, m->dns_servers) if (s->family == family && in_addr_equal(family, &s->address, &address) > 0) break; if (s) s->marked = false; else { r = dns_server_new(m, NULL, DNS_SERVER_SYSTEM, NULL, family, &address); if (r < 0) goto clear; } } LIST_FOREACH_SAFE(servers, s, nx, m->dns_servers) if (s->marked) dns_server_free(s); return 0; clear: while (m->dns_servers) dns_server_free(m->dns_servers); return r; } static void write_resolv_conf_server(DnsServer *s, FILE *f, unsigned *count) { _cleanup_free_ char *t = NULL; int r; assert(s); assert(f); assert(count); r = in_addr_to_string(s->family, &s->address, &t); if (r < 0) { log_warning_errno(r, "Invalid DNS address. Ignoring: %m"); return; } if (*count == MAXNS) fputs("# Too many DNS servers configured, the following entries may be ignored.\n", f); fprintf(f, "nameserver %s\n", t); (*count) ++; } static void write_resolv_conf_search(const char *domain, FILE *f, unsigned *count, unsigned *length) { assert(domain); assert(f); assert(length); if (*count >= MAXDNSRCH || *length + strlen(domain) > 256) { if (*count == MAXDNSRCH) fputs(" # Too many search domains configured, remaining ones ignored.", f); if (*length <= 256) fputs(" # Total length of all search domains is too long, remaining ones ignored.", f); return; } fprintf(f, " %s", domain); (*length) += strlen(domain); (*count) ++; } static int write_resolv_conf_contents(FILE *f, Set *dns, Set *domains) { Iterator i; fputs("# This file is managed by systemd-resolved(8). Do not edit.\n#\n" "# Third party programs must not access this file directly, but\n" "# only through the symlink at /etc/resolv.conf. To manage\n" "# resolv.conf(5) in a different way, replace the symlink by a\n" "# static file or a different symlink.\n\n", f); if (set_isempty(dns)) fputs("# No DNS servers known.\n", f); else { DnsServer *s; unsigned count = 0; SET_FOREACH(s, dns, i) write_resolv_conf_server(s, f, &count); } if (!set_isempty(domains)) { unsigned length = 0, count = 0; char *domain; fputs("search", f); SET_FOREACH(domain, domains, i) write_resolv_conf_search(domain, f, &count, &length); fputs("\n", f); } return fflush_and_check(f); } int manager_write_resolv_conf(Manager *m) { static const char path[] = "/run/systemd/resolve/resolv.conf"; _cleanup_free_ char *temp_path = NULL; _cleanup_fclose_ FILE *f = NULL; _cleanup_set_free_ Set *dns = NULL, *domains = NULL; DnsServer *s; Iterator i; Link *l; int r; assert(m); /* Read the system /etc/resolv.conf first */ manager_read_resolv_conf(m); /* Add the full list to a set, to filter out duplicates */ dns = set_new(&dns_server_hash_ops); if (!dns) return -ENOMEM; domains = set_new(&dns_name_hash_ops); if (!domains) return -ENOMEM; /* First add the system-wide servers */ LIST_FOREACH(servers, s, m->dns_servers) { r = set_put(dns, s); if (r == -EEXIST) continue; if (r < 0) return r; } /* Then, add the per-link servers and domains */ HASHMAP_FOREACH(l, m->links, i) { char **domain; LIST_FOREACH(servers, s, l->dns_servers) { r = set_put(dns, s); if (r == -EEXIST) continue; if (r < 0) return r; } if (!l->unicast_scope) continue; STRV_FOREACH(domain, l->unicast_scope->domains) { r = set_put(domains, *domain); if (r == -EEXIST) continue; if (r < 0) return r; } } /* If we found nothing, add the fallback servers */ if (set_isempty(dns)) { LIST_FOREACH(servers, s, m->fallback_dns_servers) { r = set_put(dns, s); if (r == -EEXIST) continue; if (r < 0) return r; } } r = fopen_temporary_label(path, path, &f, &temp_path); if (r < 0) return r; fchmod(fileno(f), 0644); r = write_resolv_conf_contents(f, dns, domains); if (r < 0) goto fail; if (rename(temp_path, path) < 0) { r = -errno; goto fail; } return 0; fail: unlink(path); unlink(temp_path); return r; } int manager_recv(Manager *m, int fd, DnsProtocol protocol, DnsPacket **ret) { _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; union { struct cmsghdr header; /* For alignment */ uint8_t buffer[CMSG_SPACE(MAXSIZE(struct in_pktinfo, struct in6_pktinfo)) + CMSG_SPACE(int) /* ttl/hoplimit */ + EXTRA_CMSG_SPACE /* kernel appears to require extra buffer space */]; } control; union sockaddr_union sa; struct msghdr mh = {}; struct cmsghdr *cmsg; struct iovec iov; int ms = 0, r; ssize_t l; assert(m); assert(fd >= 0); assert(ret); r = ioctl(fd, FIONREAD, &ms); if (r < 0) return -errno; if (ms < 0) return -EIO; r = dns_packet_new(&p, protocol, ms); if (r < 0) return r; iov.iov_base = DNS_PACKET_DATA(p); iov.iov_len = p->allocated; mh.msg_name = &sa.sa; mh.msg_namelen = sizeof(sa); mh.msg_iov = &iov; mh.msg_iovlen = 1; mh.msg_control = &control; mh.msg_controllen = sizeof(control); l = recvmsg(fd, &mh, 0); if (l < 0) { if (errno == EAGAIN || errno == EINTR) return 0; return -errno; } if (l <= 0) return -EIO; assert(!(mh.msg_flags & MSG_CTRUNC)); assert(!(mh.msg_flags & MSG_TRUNC)); p->size = (size_t) l; p->family = sa.sa.sa_family; p->ipproto = IPPROTO_UDP; if (p->family == AF_INET) { p->sender.in = sa.in.sin_addr; p->sender_port = be16toh(sa.in.sin_port); } else if (p->family == AF_INET6) { p->sender.in6 = sa.in6.sin6_addr; p->sender_port = be16toh(sa.in6.sin6_port); p->ifindex = sa.in6.sin6_scope_id; } else return -EAFNOSUPPORT; for (cmsg = CMSG_FIRSTHDR(&mh); cmsg; cmsg = CMSG_NXTHDR(&mh, cmsg)) { if (cmsg->cmsg_level == IPPROTO_IPV6) { assert(p->family == AF_INET6); switch (cmsg->cmsg_type) { case IPV6_PKTINFO: { struct in6_pktinfo *i = (struct in6_pktinfo*) CMSG_DATA(cmsg); if (p->ifindex <= 0) p->ifindex = i->ipi6_ifindex; p->destination.in6 = i->ipi6_addr; break; } case IPV6_HOPLIMIT: p->ttl = *(int *) CMSG_DATA(cmsg); break; } } else if (cmsg->cmsg_level == IPPROTO_IP) { assert(p->family == AF_INET); switch (cmsg->cmsg_type) { case IP_PKTINFO: { struct in_pktinfo *i = (struct in_pktinfo*) CMSG_DATA(cmsg); if (p->ifindex <= 0) p->ifindex = i->ipi_ifindex; p->destination.in = i->ipi_addr; break; } case IP_TTL: p->ttl = *(int *) CMSG_DATA(cmsg); break; } } } /* The Linux kernel sets the interface index to the loopback * device if the packet came from the local host since it * avoids the routing table in such a case. Let's unset the * interface index in such a case. */ if (p->ifindex == LOOPBACK_IFINDEX) p->ifindex = 0; /* If we don't know the interface index still, we look for the * first local interface with a matching address. Yuck! */ if (p->ifindex <= 0) p->ifindex = manager_find_ifindex(m, p->family, &p->destination); *ret = p; p = NULL; return 1; } static int on_dns_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) { _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; DnsTransaction *t = NULL; Manager *m = userdata; int r; r = manager_recv(m, fd, DNS_PROTOCOL_DNS, &p); if (r <= 0) return r; if (dns_packet_validate_reply(p) > 0) { t = hashmap_get(m->dns_transactions, UINT_TO_PTR(DNS_PACKET_ID(p))); if (!t) return 0; dns_transaction_process_reply(t, p); } else log_debug("Invalid DNS packet."); return 0; } int manager_dns_ipv4_fd(Manager *m) { const int one = 1; int r; assert(m); if (m->dns_ipv4_fd >= 0) return m->dns_ipv4_fd; m->dns_ipv4_fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); if (m->dns_ipv4_fd < 0) return -errno; r = setsockopt(m->dns_ipv4_fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one)); if (r < 0) { r = -errno; goto fail; } r = sd_event_add_io(m->event, &m->dns_ipv4_event_source, m->dns_ipv4_fd, EPOLLIN, on_dns_packet, m); if (r < 0) goto fail; return m->dns_ipv4_fd; fail: m->dns_ipv4_fd = safe_close(m->dns_ipv4_fd); return r; } int manager_dns_ipv6_fd(Manager *m) { const int one = 1; int r; assert(m); if (m->dns_ipv6_fd >= 0) return m->dns_ipv6_fd; m->dns_ipv6_fd = socket(AF_INET6, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); if (m->dns_ipv6_fd < 0) return -errno; r = setsockopt(m->dns_ipv6_fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &one, sizeof(one)); if (r < 0) { r = -errno; goto fail; } r = sd_event_add_io(m->event, &m->dns_ipv6_event_source, m->dns_ipv6_fd, EPOLLIN, on_dns_packet, m); if (r < 0) goto fail; return m->dns_ipv6_fd; fail: m->dns_ipv6_fd = safe_close(m->dns_ipv6_fd); return r; } static int sendmsg_loop(int fd, struct msghdr *mh, int flags) { int r; assert(fd >= 0); assert(mh); for (;;) { if (sendmsg(fd, mh, flags) >= 0) return 0; if (errno == EINTR) continue; if (errno != EAGAIN) return -errno; r = fd_wait_for_event(fd, POLLOUT, SEND_TIMEOUT_USEC); if (r < 0) return r; if (r == 0) return -ETIMEDOUT; } } static int manager_ipv4_send(Manager *m, int fd, int ifindex, const struct in_addr *addr, uint16_t port, DnsPacket *p) { union sockaddr_union sa = { .in.sin_family = AF_INET, }; union { struct cmsghdr header; /* For alignment */ uint8_t buffer[CMSG_SPACE(sizeof(struct in_pktinfo))]; } control; struct msghdr mh = {}; struct iovec iov; assert(m); assert(fd >= 0); assert(addr); assert(port > 0); assert(p); iov.iov_base = DNS_PACKET_DATA(p); iov.iov_len = p->size; sa.in.sin_addr = *addr; sa.in.sin_port = htobe16(port), mh.msg_iov = &iov; mh.msg_iovlen = 1; mh.msg_name = &sa.sa; mh.msg_namelen = sizeof(sa.in); if (ifindex > 0) { struct cmsghdr *cmsg; struct in_pktinfo *pi; zero(control); mh.msg_control = &control; mh.msg_controllen = CMSG_LEN(sizeof(struct in_pktinfo)); cmsg = CMSG_FIRSTHDR(&mh); cmsg->cmsg_len = mh.msg_controllen; cmsg->cmsg_level = IPPROTO_IP; cmsg->cmsg_type = IP_PKTINFO; pi = (struct in_pktinfo*) CMSG_DATA(cmsg); pi->ipi_ifindex = ifindex; } return sendmsg_loop(fd, &mh, 0); } static int manager_ipv6_send(Manager *m, int fd, int ifindex, const struct in6_addr *addr, uint16_t port, DnsPacket *p) { union sockaddr_union sa = { .in6.sin6_family = AF_INET6, }; union { struct cmsghdr header; /* For alignment */ uint8_t buffer[CMSG_SPACE(sizeof(struct in6_pktinfo))]; } control; struct msghdr mh = {}; struct iovec iov; assert(m); assert(fd >= 0); assert(addr); assert(port > 0); assert(p); iov.iov_base = DNS_PACKET_DATA(p); iov.iov_len = p->size; sa.in6.sin6_addr = *addr; sa.in6.sin6_port = htobe16(port), sa.in6.sin6_scope_id = ifindex; mh.msg_iov = &iov; mh.msg_iovlen = 1; mh.msg_name = &sa.sa; mh.msg_namelen = sizeof(sa.in6); if (ifindex > 0) { struct cmsghdr *cmsg; struct in6_pktinfo *pi; zero(control); mh.msg_control = &control; mh.msg_controllen = CMSG_LEN(sizeof(struct in6_pktinfo)); cmsg = CMSG_FIRSTHDR(&mh); cmsg->cmsg_len = mh.msg_controllen; cmsg->cmsg_level = IPPROTO_IPV6; cmsg->cmsg_type = IPV6_PKTINFO; pi = (struct in6_pktinfo*) CMSG_DATA(cmsg); pi->ipi6_ifindex = ifindex; } return sendmsg_loop(fd, &mh, 0); } int manager_send(Manager *m, int fd, int ifindex, int family, const union in_addr_union *addr, uint16_t port, DnsPacket *p) { assert(m); assert(fd >= 0); assert(addr); assert(port > 0); assert(p); log_debug("Sending %s packet with id %u on interface %i/%s", DNS_PACKET_QR(p) ? "response" : "query", DNS_PACKET_ID(p), ifindex, af_to_name(family)); if (family == AF_INET) return manager_ipv4_send(m, fd, ifindex, &addr->in, port, p); else if (family == AF_INET6) return manager_ipv6_send(m, fd, ifindex, &addr->in6, port, p); return -EAFNOSUPPORT; } DnsServer* manager_find_dns_server(Manager *m, int family, const union in_addr_union *in_addr) { DnsServer *s; assert(m); assert(in_addr); LIST_FOREACH(servers, s, m->dns_servers) if (s->family == family && in_addr_equal(family, &s->address, in_addr) > 0) return s; LIST_FOREACH(servers, s, m->fallback_dns_servers) if (s->family == family && in_addr_equal(family, &s->address, in_addr) > 0) return s; return NULL; } DnsServer *manager_set_dns_server(Manager *m, DnsServer *s) { assert(m); if (m->current_dns_server == s) return s; if (s) { _cleanup_free_ char *ip = NULL; in_addr_to_string(s->family, &s->address, &ip); log_info("Switching to system DNS server %s.", strna(ip)); } m->current_dns_server = s; if (m->unicast_scope) dns_cache_flush(&m->unicast_scope->cache); return s; } DnsServer *manager_get_dns_server(Manager *m) { Link *l; assert(m); /* Try to read updates resolv.conf */ manager_read_resolv_conf(m); if (!m->current_dns_server) manager_set_dns_server(m, m->dns_servers); if (!m->current_dns_server) { bool found = false; Iterator i; /* No DNS servers configured, let's see if there are * any on any links. If not, we use the fallback * servers */ HASHMAP_FOREACH(l, m->links, i) if (l->dns_servers) { found = true; break; } if (!found) manager_set_dns_server(m, m->fallback_dns_servers); } return m->current_dns_server; } void manager_next_dns_server(Manager *m) { assert(m); /* If there's currently no DNS server set, then the next * manager_get_dns_server() will find one */ if (!m->current_dns_server) return; /* Change to the next one */ if (m->current_dns_server->servers_next) { manager_set_dns_server(m, m->current_dns_server->servers_next); return; } /* If there was no next one, then start from the beginning of * the list */ if (m->current_dns_server->type == DNS_SERVER_FALLBACK) manager_set_dns_server(m, m->fallback_dns_servers); else manager_set_dns_server(m, m->dns_servers); } uint32_t manager_find_mtu(Manager *m) { uint32_t mtu = 0; Link *l; Iterator i; /* If we don't know on which link a DNS packet would be * delivered, let's find the largest MTU that works on all * interfaces we know of */ HASHMAP_FOREACH(l, m->links, i) { if (l->mtu <= 0) continue; if (mtu <= 0 || l->mtu < mtu) mtu = l->mtu; } return mtu; } static int on_llmnr_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) { _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; DnsTransaction *t = NULL; Manager *m = userdata; DnsScope *scope; int r; r = manager_recv(m, fd, DNS_PROTOCOL_LLMNR, &p); if (r <= 0) return r; scope = manager_find_scope(m, p); if (!scope) { log_warning("Got LLMNR UDP packet on unknown scope. Ignoring."); return 0; } if (dns_packet_validate_reply(p) > 0) { log_debug("Got reply packet for id %u", DNS_PACKET_ID(p)); dns_scope_check_conflicts(scope, p); t = hashmap_get(m->dns_transactions, UINT_TO_PTR(DNS_PACKET_ID(p))); if (t) dns_transaction_process_reply(t, p); } else if (dns_packet_validate_query(p) > 0) { log_debug("Got query packet for id %u", DNS_PACKET_ID(p)); dns_scope_process_query(scope, NULL, p); } else log_debug("Invalid LLMNR UDP packet."); return 0; } int manager_llmnr_ipv4_udp_fd(Manager *m) { union sockaddr_union sa = { .in.sin_family = AF_INET, .in.sin_port = htobe16(5355), }; static const int one = 1, pmtu = IP_PMTUDISC_DONT, ttl = 255; int r; assert(m); if (m->llmnr_ipv4_udp_fd >= 0) return m->llmnr_ipv4_udp_fd; m->llmnr_ipv4_udp_fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); if (m->llmnr_ipv4_udp_fd < 0) return -errno; /* RFC 4795, section 2.5 recommends setting the TTL of UDP packets to 255. */ r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_TTL, &ttl, sizeof(ttl)); if (r < 0) { r = -errno; goto fail; } r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl)); if (r < 0) { r = -errno; goto fail; } r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_MULTICAST_LOOP, &one, sizeof(one)); if (r < 0) { r = -errno; goto fail; } r = setsockopt(m->llmnr_ipv4_udp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)); if (r < 0) { r = -errno; goto fail; } r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one)); if (r < 0) { r = -errno; goto fail; } r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_RECVTTL, &one, sizeof(one)); if (r < 0) { r = -errno; goto fail; } /* Disable Don't-Fragment bit in the IP header */ r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_MTU_DISCOVER, &pmtu, sizeof(pmtu)); if (r < 0) { r = -errno; goto fail; } r = bind(m->llmnr_ipv4_udp_fd, &sa.sa, sizeof(sa.in)); if (r < 0) { r = -errno; goto fail; } r = sd_event_add_io(m->event, &m->llmnr_ipv4_udp_event_source, m->llmnr_ipv4_udp_fd, EPOLLIN, on_llmnr_packet, m); if (r < 0) goto fail; return m->llmnr_ipv4_udp_fd; fail: m->llmnr_ipv4_udp_fd = safe_close(m->llmnr_ipv4_udp_fd); return r; } int manager_llmnr_ipv6_udp_fd(Manager *m) { union sockaddr_union sa = { .in6.sin6_family = AF_INET6, .in6.sin6_port = htobe16(5355), }; static const int one = 1, ttl = 255; int r; assert(m); if (m->llmnr_ipv6_udp_fd >= 0) return m->llmnr_ipv6_udp_fd; m->llmnr_ipv6_udp_fd = socket(AF_INET6, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); if (m->llmnr_ipv6_udp_fd < 0) return -errno; r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &ttl, sizeof(ttl)); if (r < 0) { r = -errno; goto fail; } /* RFC 4795, section 2.5 recommends setting the TTL of UDP packets to 255. */ r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &ttl, sizeof(ttl)); if (r < 0) { r = -errno; goto fail; } r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &one, sizeof(one)); if (r < 0) { r = -errno; goto fail; } r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one)); if (r < 0) { r = -errno; goto fail; } r = setsockopt(m->llmnr_ipv6_udp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)); if (r < 0) { r = -errno; goto fail; } r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &one, sizeof(one)); if (r < 0) { r = -errno; goto fail; } r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &one, sizeof(one)); if (r < 0) { r = -errno; goto fail; } r = bind(m->llmnr_ipv6_udp_fd, &sa.sa, sizeof(sa.in6)); if (r < 0) { r = -errno; goto fail; } r = sd_event_add_io(m->event, &m->llmnr_ipv6_udp_event_source, m->llmnr_ipv6_udp_fd, EPOLLIN, on_llmnr_packet, m); if (r < 0) { r = -errno; goto fail; } return m->llmnr_ipv6_udp_fd; fail: m->llmnr_ipv6_udp_fd = safe_close(m->llmnr_ipv6_udp_fd); return r; } static int on_llmnr_stream_packet(DnsStream *s) { DnsScope *scope; assert(s); scope = manager_find_scope(s->manager, s->read_packet); if (!scope) { log_warning("Got LLMNR TCP packet on unknown scope. Ignroing."); return 0; } if (dns_packet_validate_query(s->read_packet) > 0) { log_debug("Got query packet for id %u", DNS_PACKET_ID(s->read_packet)); dns_scope_process_query(scope, s, s->read_packet); /* If no reply packet was set, we free the stream */ if (s->write_packet) return 0; } else log_debug("Invalid LLMNR TCP packet."); dns_stream_free(s); return 0; } static int on_llmnr_stream(sd_event_source *s, int fd, uint32_t revents, void *userdata) { DnsStream *stream; Manager *m = userdata; int cfd, r; cfd = accept4(fd, NULL, NULL, SOCK_NONBLOCK|SOCK_CLOEXEC); if (cfd < 0) { if (errno == EAGAIN || errno == EINTR) return 0; return -errno; } r = dns_stream_new(m, &stream, DNS_PROTOCOL_LLMNR, cfd); if (r < 0) { safe_close(cfd); return r; } stream->on_packet = on_llmnr_stream_packet; return 0; } int manager_llmnr_ipv4_tcp_fd(Manager *m) { union sockaddr_union sa = { .in.sin_family = AF_INET, .in.sin_port = htobe16(5355), }; static const int one = 1, pmtu = IP_PMTUDISC_DONT; int r; assert(m); if (m->llmnr_ipv4_tcp_fd >= 0) return m->llmnr_ipv4_tcp_fd; m->llmnr_ipv4_tcp_fd = socket(AF_INET, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); if (m->llmnr_ipv4_tcp_fd < 0) return -errno; /* RFC 4795, section 2.5. requires setting the TTL of TCP streams to 1 */ r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_TTL, &one, sizeof(one)); if (r < 0) { r = -errno; goto fail; } r = setsockopt(m->llmnr_ipv4_tcp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)); if (r < 0) { r = -errno; goto fail; } r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one)); if (r < 0) { r = -errno; goto fail; } r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_RECVTTL, &one, sizeof(one)); if (r < 0) { r = -errno; goto fail; } /* Disable Don't-Fragment bit in the IP header */ r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_MTU_DISCOVER, &pmtu, sizeof(pmtu)); if (r < 0) { r = -errno; goto fail; } r = bind(m->llmnr_ipv4_tcp_fd, &sa.sa, sizeof(sa.in)); if (r < 0) { r = -errno; goto fail; } r = listen(m->llmnr_ipv4_tcp_fd, SOMAXCONN); if (r < 0) { r = -errno; goto fail; } r = sd_event_add_io(m->event, &m->llmnr_ipv4_tcp_event_source, m->llmnr_ipv4_tcp_fd, EPOLLIN, on_llmnr_stream, m); if (r < 0) goto fail; return m->llmnr_ipv4_tcp_fd; fail: m->llmnr_ipv4_tcp_fd = safe_close(m->llmnr_ipv4_tcp_fd); return r; } int manager_llmnr_ipv6_tcp_fd(Manager *m) { union sockaddr_union sa = { .in6.sin6_family = AF_INET6, .in6.sin6_port = htobe16(5355), }; static const int one = 1; int r; assert(m); if (m->llmnr_ipv6_tcp_fd >= 0) return m->llmnr_ipv6_tcp_fd; m->llmnr_ipv6_tcp_fd = socket(AF_INET6, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); if (m->llmnr_ipv6_tcp_fd < 0) return -errno; /* RFC 4795, section 2.5. requires setting the TTL of TCP streams to 1 */ r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &one, sizeof(one)); if (r < 0) { r = -errno; goto fail; } r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one)); if (r < 0) { r = -errno; goto fail; } r = setsockopt(m->llmnr_ipv6_tcp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)); if (r < 0) { r = -errno; goto fail; } r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &one, sizeof(one)); if (r < 0) { r = -errno; goto fail; } r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &one, sizeof(one)); if (r < 0) { r = -errno; goto fail; } r = bind(m->llmnr_ipv6_tcp_fd, &sa.sa, sizeof(sa.in6)); if (r < 0) { r = -errno; goto fail; } r = listen(m->llmnr_ipv6_tcp_fd, SOMAXCONN); if (r < 0) { r = -errno; goto fail; } r = sd_event_add_io(m->event, &m->llmnr_ipv6_tcp_event_source, m->llmnr_ipv6_tcp_fd, EPOLLIN, on_llmnr_stream, m); if (r < 0) { r = -errno; goto fail; } return m->llmnr_ipv6_tcp_fd; fail: m->llmnr_ipv6_tcp_fd = safe_close(m->llmnr_ipv6_tcp_fd); return r; } int manager_find_ifindex(Manager *m, int family, const union in_addr_union *in_addr) { LinkAddress *a; assert(m); a = manager_find_link_address(m, family, in_addr); if (a) return a->link->ifindex; return 0; } void manager_refresh_rrs(Manager *m) { Iterator i; Link *l; assert(m); m->host_ipv4_key = dns_resource_key_unref(m->host_ipv4_key); m->host_ipv6_key = dns_resource_key_unref(m->host_ipv6_key); HASHMAP_FOREACH(l, m->links, i) { link_add_rrs(l, true); link_add_rrs(l, false); } } int manager_next_hostname(Manager *m) { const char *p; uint64_t u, a; char *h; assert(m); p = strchr(m->hostname, 0); assert(p); while (p > m->hostname) { if (!strchr("0123456789", p[-1])) break; p--; } if (*p == 0 || safe_atou64(p, &u) < 0 || u <= 0) u = 1; /* Add a random number to the old value. This way we can avoid * that two hosts pick the same hostname, win on IPv4 and lose * on IPv6 (or vice versa), and pick the same hostname * replacement hostname, ad infinitum. We still want the * numbers to go up monotonically, hence we just add a random * value 1..10 */ random_bytes(&a, sizeof(a)); u += 1 + a % 10; if (asprintf(&h, "%.*s%" PRIu64, (int) (p - m->hostname), m->hostname, u) < 0) return -ENOMEM; log_info("Hostname conflict, changing published hostname from '%s' to '%s'.", m->hostname, h); free(m->hostname); m->hostname = h; manager_refresh_rrs(m); return 0; } LinkAddress* manager_find_link_address(Manager *m, int family, const union in_addr_union *in_addr) { Iterator i; Link *l; assert(m); HASHMAP_FOREACH(l, m->links, i) { LinkAddress *a; a = link_find_address(l, family, in_addr); if (a) return a; } return NULL; } bool manager_our_packet(Manager *m, DnsPacket *p) { assert(m); assert(p); return !!manager_find_link_address(m, p->family, &p->sender); } DnsScope* manager_find_scope(Manager *m, DnsPacket *p) { Link *l; assert(m); assert(p); l = hashmap_get(m->links, INT_TO_PTR(p->ifindex)); if (!l) return NULL; if (p->protocol == DNS_PROTOCOL_LLMNR) { if (p->family == AF_INET) return l->llmnr_ipv4_scope; else if (p->family == AF_INET6) return l->llmnr_ipv6_scope; } return NULL; } void manager_verify_all(Manager *m) { DnsScope *s; assert(m); LIST_FOREACH(scopes, s, m->dns_scopes) dns_zone_verify_all(&s->zone); } void manager_flush_dns_servers(Manager *m, DnsServerType t) { assert(m); if (t == DNS_SERVER_SYSTEM) while (m->dns_servers) dns_server_free(m->dns_servers); if (t == DNS_SERVER_FALLBACK) while (m->fallback_dns_servers) dns_server_free(m->fallback_dns_servers); } static const char* const support_table[_SUPPORT_MAX] = { [SUPPORT_NO] = "no", [SUPPORT_YES] = "yes", [SUPPORT_RESOLVE] = "resolve", }; DEFINE_STRING_TABLE_LOOKUP(support, Support);