1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
4 This file is part of systemd.
6 Copyright 2014 Lennart Poettering
8 systemd is free software; you can redistribute it and/or modify it
9 under the terms of the GNU Lesser General Public License as published by
10 the Free Software Foundation; either version 2.1 of the License, or
11 (at your option) any later version.
13 systemd is distributed in the hope that it will be useful, but
14 WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 Lesser General Public License for more details.
18 You should have received a copy of the GNU Lesser General Public License
19 along with systemd; If not, see <http://www.gnu.org/licenses/>.
22 #include <netinet/tcp.h>
26 #include "socket-util.h"
28 #include "resolved-dns-domain.h"
29 #include "resolved-dns-scope.h"
31 #define MULTICAST_RATELIMIT_INTERVAL_USEC (1*USEC_PER_SEC)
32 #define MULTICAST_RATELIMIT_BURST 1000
34 int dns_scope_new(Manager *m, DnsScope **ret, Link *l, DnsProtocol protocol, int family) {
40 s = new0(DnsScope, 1);
46 s->protocol = protocol;
49 LIST_PREPEND(scopes, m->dns_scopes, s);
51 dns_scope_llmnr_membership(s, true);
53 log_debug("New scope on link %s, protocol %s, family %s", l ? l->name : "*", dns_protocol_to_string(protocol), family == AF_UNSPEC ? "*" : af_to_name(family));
55 /* Enforce ratelimiting for the multicast protocols */
56 RATELIMIT_INIT(s->ratelimit, MULTICAST_RATELIMIT_INTERVAL_USEC, MULTICAST_RATELIMIT_BURST);
62 DnsScope* dns_scope_free(DnsScope *s) {
64 DnsResourceRecord *rr;
69 log_debug("Removing scope on link %s, protocol %s, family %s", s->link ? s->link->name : "*", dns_protocol_to_string(s->protocol), s->family == AF_UNSPEC ? "*" : af_to_name(s->family));
71 dns_scope_llmnr_membership(s, false);
73 while ((t = s->transactions)) {
75 /* Abort the transaction, but make sure it is not
76 * freed while we still look at it */
79 dns_transaction_complete(t, DNS_TRANSACTION_ABORTED);
82 dns_transaction_free(t);
85 while ((rr = hashmap_steal_first(s->conflict_queue)))
86 dns_resource_record_unref(rr);
88 hashmap_free(s->conflict_queue);
89 sd_event_source_unref(s->conflict_event_source);
91 dns_cache_flush(&s->cache);
92 dns_zone_flush(&s->zone);
94 LIST_REMOVE(scopes, s->manager->dns_scopes, s);
95 strv_free(s->domains);
101 DnsServer *dns_scope_get_dns_server(DnsScope *s) {
104 if (s->protocol != DNS_PROTOCOL_DNS)
108 return link_get_dns_server(s->link);
110 return manager_get_dns_server(s->manager);
113 void dns_scope_next_dns_server(DnsScope *s) {
116 if (s->protocol != DNS_PROTOCOL_DNS)
120 link_next_dns_server(s->link);
122 manager_next_dns_server(s->manager);
125 int dns_scope_emit(DnsScope *s, DnsPacket *p) {
126 union in_addr_union addr;
135 assert(p->protocol == s->protocol);
139 ifindex = s->link->ifindex;
141 mtu = manager_find_mtu(s->manager);
143 if (s->protocol == DNS_PROTOCOL_DNS) {
146 if (DNS_PACKET_QDCOUNT(p) > 1)
149 srv = dns_scope_get_dns_server(s);
153 family = srv->family;
157 if (p->size > DNS_PACKET_UNICAST_SIZE_MAX)
163 if (family == AF_INET)
164 fd = manager_dns_ipv4_fd(s->manager);
165 else if (family == AF_INET6)
166 fd = manager_dns_ipv6_fd(s->manager);
168 return -EAFNOSUPPORT;
172 } else if (s->protocol == DNS_PROTOCOL_LLMNR) {
174 if (DNS_PACKET_QDCOUNT(p) > 1)
177 if (!ratelimit_test(&s->ratelimit))
183 if (family == AF_INET) {
184 addr.in = LLMNR_MULTICAST_IPV4_ADDRESS;
185 fd = manager_llmnr_ipv4_udp_fd(s->manager);
186 } else if (family == AF_INET6) {
187 addr.in6 = LLMNR_MULTICAST_IPV6_ADDRESS;
188 fd = manager_llmnr_ipv6_udp_fd(s->manager);
190 return -EAFNOSUPPORT;
194 return -EAFNOSUPPORT;
196 r = manager_send(s->manager, fd, ifindex, family, &addr, port, p);
203 int dns_scope_tcp_socket(DnsScope *s, int family, const union in_addr_union *address, uint16_t port) {
204 _cleanup_close_ int fd = -1;
205 union sockaddr_union sa = {};
207 static const int one = 1;
211 assert((family == AF_UNSPEC) == !address);
213 if (family == AF_UNSPEC) {
216 srv = dns_scope_get_dns_server(s);
220 sa.sa.sa_family = srv->family;
221 if (srv->family == AF_INET) {
222 sa.in.sin_port = htobe16(port);
223 sa.in.sin_addr = srv->address.in;
224 salen = sizeof(sa.in);
225 } else if (srv->family == AF_INET6) {
226 sa.in6.sin6_port = htobe16(port);
227 sa.in6.sin6_addr = srv->address.in6;
228 sa.in6.sin6_scope_id = s->link ? s->link->ifindex : 0;
229 salen = sizeof(sa.in6);
231 return -EAFNOSUPPORT;
233 sa.sa.sa_family = family;
235 if (family == AF_INET) {
236 sa.in.sin_port = htobe16(port);
237 sa.in.sin_addr = address->in;
238 salen = sizeof(sa.in);
239 } else if (family == AF_INET6) {
240 sa.in6.sin6_port = htobe16(port);
241 sa.in6.sin6_addr = address->in6;
242 sa.in6.sin6_scope_id = s->link ? s->link->ifindex : 0;
243 salen = sizeof(sa.in6);
245 return -EAFNOSUPPORT;
248 fd = socket(sa.sa.sa_family, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
252 r = setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &one, sizeof(one));
257 uint32_t ifindex = htobe32(s->link->ifindex);
259 if (sa.sa.sa_family == AF_INET) {
260 r = setsockopt(fd, IPPROTO_IP, IP_UNICAST_IF, &ifindex, sizeof(ifindex));
263 } else if (sa.sa.sa_family == AF_INET6) {
264 r = setsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_IF, &ifindex, sizeof(ifindex));
270 if (s->protocol == DNS_PROTOCOL_LLMNR) {
271 /* RFC 4795, section 2.5 requires the TTL to be set to 1 */
273 if (sa.sa.sa_family == AF_INET) {
274 r = setsockopt(fd, IPPROTO_IP, IP_TTL, &one, sizeof(one));
277 } else if (sa.sa.sa_family == AF_INET6) {
278 r = setsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &one, sizeof(one));
284 r = connect(fd, &sa.sa, salen);
285 if (r < 0 && errno != EINPROGRESS)
294 DnsScopeMatch dns_scope_good_domain(DnsScope *s, int ifindex, uint64_t flags, const char *domain) {
300 if (ifindex != 0 && (!s->link || s->link->ifindex != ifindex))
303 if ((SD_RESOLVED_FLAGS_MAKE(s->protocol, s->family) & flags) == 0)
306 STRV_FOREACH(i, s->domains)
307 if (dns_name_endswith(domain, *i) > 0)
308 return DNS_SCOPE_YES;
310 if (dns_name_root(domain) != 0)
313 if (is_localhost(domain))
316 if (s->protocol == DNS_PROTOCOL_DNS) {
317 if (dns_name_endswith(domain, "254.169.in-addr.arpa") == 0 &&
318 dns_name_endswith(domain, "0.8.e.f.ip6.arpa") == 0 &&
319 dns_name_single_label(domain) == 0)
320 return DNS_SCOPE_MAYBE;
325 if (s->protocol == DNS_PROTOCOL_MDNS) {
326 if (dns_name_endswith(domain, "254.169.in-addr.arpa") > 0 ||
327 dns_name_endswith(domain, "0.8.e.f.ip6.arpa") > 0 ||
328 (dns_name_endswith(domain, "local") > 0 && dns_name_equal(domain, "local") == 0))
329 return DNS_SCOPE_MAYBE;
334 if (s->protocol == DNS_PROTOCOL_LLMNR) {
335 if (dns_name_endswith(domain, "in-addr.arpa") > 0 ||
336 dns_name_endswith(domain, "ip6.arpa") > 0 ||
337 dns_name_single_label(domain) > 0)
338 return DNS_SCOPE_MAYBE;
343 assert_not_reached("Unknown scope protocol");
346 int dns_scope_good_key(DnsScope *s, DnsResourceKey *key) {
350 if (s->protocol == DNS_PROTOCOL_DNS)
353 /* On mDNS and LLMNR, send A and AAAA queries only on the
354 * respective scopes */
356 if (s->family == AF_INET && key->class == DNS_CLASS_IN && key->type == DNS_TYPE_AAAA)
359 if (s->family == AF_INET6 && key->class == DNS_CLASS_IN && key->type == DNS_TYPE_A)
365 int dns_scope_llmnr_membership(DnsScope *s, bool b) {
368 if (s->family == AF_INET) {
369 struct ip_mreqn mreqn = {
370 .imr_multiaddr = LLMNR_MULTICAST_IPV4_ADDRESS,
371 .imr_ifindex = s->link->ifindex,
374 fd = manager_llmnr_ipv4_udp_fd(s->manager);
378 /* Always first try to drop membership before we add
379 * one. This is necessary on some devices, such as
382 setsockopt(fd, IPPROTO_IP, IP_DROP_MEMBERSHIP, &mreqn, sizeof(mreqn));
384 if (setsockopt(fd, IPPROTO_IP, b ? IP_ADD_MEMBERSHIP : IP_DROP_MEMBERSHIP, &mreqn, sizeof(mreqn)) < 0)
387 } else if (s->family == AF_INET6) {
388 struct ipv6_mreq mreq = {
389 .ipv6mr_multiaddr = LLMNR_MULTICAST_IPV6_ADDRESS,
390 .ipv6mr_interface = s->link->ifindex,
393 fd = manager_llmnr_ipv6_udp_fd(s->manager);
398 setsockopt(fd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP, &mreq, sizeof(mreq));
400 if (setsockopt(fd, IPPROTO_IPV6, b ? IPV6_ADD_MEMBERSHIP : IPV6_DROP_MEMBERSHIP, &mreq, sizeof(mreq)) < 0)
403 return -EAFNOSUPPORT;
408 int dns_scope_good_dns_server(DnsScope *s, int family, const union in_addr_union *address) {
412 if (s->protocol != DNS_PROTOCOL_DNS)
416 return !!link_find_dns_server(s->link, family, address);
418 return !!manager_find_dns_server(s->manager, family, address);
421 static int dns_scope_make_reply_packet(
431 _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
438 if ((!q || q->n_keys <= 0)
439 && (!answer || answer->n_rrs <= 0)
440 && (!soa || soa->n_rrs <= 0))
443 r = dns_packet_new(&p, s->protocol, 0);
447 DNS_PACKET_HEADER(p)->id = id;
448 DNS_PACKET_HEADER(p)->flags = htobe16(DNS_PACKET_MAKE_FLAGS(
460 for (i = 0; i < q->n_keys; i++) {
461 r = dns_packet_append_key(p, q->keys[i], NULL);
466 DNS_PACKET_HEADER(p)->qdcount = htobe16(q->n_keys);
470 for (i = 0; i < answer->n_rrs; i++) {
471 r = dns_packet_append_rr(p, answer->rrs[i], NULL);
476 DNS_PACKET_HEADER(p)->ancount = htobe16(answer->n_rrs);
480 for (i = 0; i < soa->n_rrs; i++) {
481 r = dns_packet_append_rr(p, soa->rrs[i], NULL);
486 DNS_PACKET_HEADER(p)->arcount = htobe16(soa->n_rrs);
495 static void dns_scope_verify_conflicts(DnsScope *s, DnsPacket *p) {
502 for (n = 0; n < p->question->n_keys; n++)
503 dns_zone_verify_conflicts(&s->zone, p->question->keys[n]);
505 for (n = 0; n < p->answer->n_rrs; n++)
506 dns_zone_verify_conflicts(&s->zone, p->answer->rrs[n]->key);
509 void dns_scope_process_query(DnsScope *s, DnsStream *stream, DnsPacket *p) {
510 _cleanup_(dns_packet_unrefp) DnsPacket *reply = NULL;
511 _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL, *soa = NULL;
512 bool tentative = false;
518 if (p->protocol != DNS_PROTOCOL_LLMNR)
521 if (p->ipproto == IPPROTO_UDP) {
522 /* Don't accept UDP queries directed to anything but
523 * the LLMNR multicast addresses. See RFC 4795,
526 if (p->family == AF_INET && !in_addr_equal(AF_INET, &p->destination, (union in_addr_union*) &LLMNR_MULTICAST_IPV4_ADDRESS))
529 if (p->family == AF_INET6 && !in_addr_equal(AF_INET6, &p->destination, (union in_addr_union*) &LLMNR_MULTICAST_IPV6_ADDRESS))
533 r = dns_packet_extract(p);
535 log_debug("Failed to extract resources from incoming packet: %s", strerror(-r));
539 if (DNS_PACKET_C(p)) {
540 /* Somebody notified us about a possible conflict */
541 dns_scope_verify_conflicts(s, p);
545 r = dns_zone_lookup(&s->zone, p->question, &answer, &soa, &tentative);
547 log_debug("Failed to lookup key: %s", strerror(-r));
554 dns_answer_order_by_scope(answer, in_addr_is_link_local(p->family, &p->sender) > 0);
556 r = dns_scope_make_reply_packet(s, DNS_PACKET_ID(p), DNS_RCODE_SUCCESS, p->question, answer, soa, tentative, &reply);
558 log_debug("Failed to build reply packet: %s", strerror(-r));
563 r = dns_stream_write_packet(stream, reply);
565 if (!ratelimit_test(&s->ratelimit))
568 if (p->family == AF_INET)
569 fd = manager_llmnr_ipv4_udp_fd(s->manager);
570 else if (p->family == AF_INET6)
571 fd = manager_llmnr_ipv6_udp_fd(s->manager);
573 log_debug("Unknown protocol");
577 log_debug("Failed to get reply socket: %s", strerror(-fd));
581 /* Note that we always immediately reply to all LLMNR
582 * requests, and do not wait any time, since we
583 * verified uniqueness for all records. Also see RFC
584 * 4795, Section 2.7 */
586 r = manager_send(s->manager, fd, p->ifindex, p->family, &p->sender, p->sender_port, reply);
590 log_debug("Failed to send reply packet: %s", strerror(-r));
595 DnsTransaction *dns_scope_find_transaction(DnsScope *scope, DnsQuestion *question, bool cache_ok) {
601 /* Try to find an ongoing transaction that is a equal or a
602 * superset of the specified question */
604 LIST_FOREACH(transactions_by_scope, t, scope->transactions) {
606 /* Refuse reusing transactions that completed based on
607 * cached data instead of a real packet, if that's
610 IN_SET(t->state, DNS_TRANSACTION_SUCCESS, DNS_TRANSACTION_FAILURE) &&
614 if (dns_question_is_superset(t->question, question) > 0)
621 static int dns_scope_make_conflict_packet(
623 DnsResourceRecord *rr,
626 _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
633 r = dns_packet_new(&p, s->protocol, 0);
637 DNS_PACKET_HEADER(p)->flags = htobe16(DNS_PACKET_MAKE_FLAGS(
647 random_bytes(&DNS_PACKET_HEADER(p)->id, sizeof(uint16_t));
648 DNS_PACKET_HEADER(p)->qdcount = htobe16(1);
649 DNS_PACKET_HEADER(p)->arcount = htobe16(1);
651 r = dns_packet_append_key(p, rr->key, NULL);
655 r = dns_packet_append_rr(p, rr, NULL);
665 static int on_conflict_dispatch(sd_event_source *es, usec_t usec, void *userdata) {
666 DnsScope *scope = userdata;
672 scope->conflict_event_source = sd_event_source_unref(scope->conflict_event_source);
675 _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
676 _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
678 rr = hashmap_steal_first(scope->conflict_queue);
682 r = dns_scope_make_conflict_packet(scope, rr, &p);
684 log_error("Failed to make conflict packet: %s", strerror(-r));
688 r = dns_scope_emit(scope, p);
690 log_debug("Failed to send conflict packet: %s", strerror(-r));
696 int dns_scope_notify_conflict(DnsScope *scope, DnsResourceRecord *rr) {
703 /* We don't send these queries immediately. Instead, we queue
704 * them, and send them after some jitter delay. */
705 r = hashmap_ensure_allocated(&scope->conflict_queue, dns_resource_key_hash_func, dns_resource_key_compare_func);
711 /* We only place one RR per key in the conflict
712 * messages, not all of them. That should be enough to
713 * indicate where there might be a conflict */
714 r = hashmap_put(scope->conflict_queue, rr->key, rr);
715 if (r == -EEXIST || r == 0)
718 log_debug("Failed to queue conflicting RR: %s", strerror(-r));
722 dns_resource_record_ref(rr);
724 if (scope->conflict_event_source)
727 random_bytes(&jitter, sizeof(jitter));
728 jitter %= LLMNR_JITTER_INTERVAL_USEC;
730 r = sd_event_add_time(scope->manager->event,
731 &scope->conflict_event_source,
732 clock_boottime_or_monotonic(),
733 now(clock_boottime_or_monotonic()) + jitter,
734 LLMNR_JITTER_INTERVAL_USEC,
735 on_conflict_dispatch, scope);
737 log_debug("Failed to add conflict dispatch event: %s", strerror(-r));
744 void dns_scope_check_conflicts(DnsScope *scope, DnsPacket *p) {
751 if (p->protocol != DNS_PROTOCOL_LLMNR)
754 if (DNS_PACKET_RRCOUNT(p) <= 0)
757 if (DNS_PACKET_C(p) != 0)
760 if (DNS_PACKET_T(p) != 0)
763 if (manager_our_packet(scope->manager, p))
766 r = dns_packet_extract(p);
768 log_debug("Failed to extract packet: %s", strerror(-r));
772 log_debug("Checking for conflicts...");
774 for (i = 0; i < p->answer->n_rrs; i++) {
776 /* Check for conflicts against the local zone. If we
777 * found one, we won't check any further */
778 r = dns_zone_check_conflicts(&scope->zone, p->answer->rrs[i]);
782 /* Check for conflicts against the local cache. If so,
783 * send out an advisory query, to inform everybody */
784 r = dns_cache_check_conflicts(&scope->cache, p->answer->rrs[i], p->family, &p->sender);
788 dns_scope_notify_conflict(scope, p->answer->rrs[i]);