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) {
369 assert(s->protocol == DNS_PROTOCOL_LLMNR);
372 if (s->family == AF_INET) {
373 struct ip_mreqn mreqn = {
374 .imr_multiaddr = LLMNR_MULTICAST_IPV4_ADDRESS,
375 .imr_ifindex = s->link->ifindex,
378 fd = manager_llmnr_ipv4_udp_fd(s->manager);
382 /* Always first try to drop membership before we add
383 * one. This is necessary on some devices, such as
386 setsockopt(fd, IPPROTO_IP, IP_DROP_MEMBERSHIP, &mreqn, sizeof(mreqn));
388 if (setsockopt(fd, IPPROTO_IP, b ? IP_ADD_MEMBERSHIP : IP_DROP_MEMBERSHIP, &mreqn, sizeof(mreqn)) < 0)
391 } else if (s->family == AF_INET6) {
392 struct ipv6_mreq mreq = {
393 .ipv6mr_multiaddr = LLMNR_MULTICAST_IPV6_ADDRESS,
394 .ipv6mr_interface = s->link->ifindex,
397 fd = manager_llmnr_ipv6_udp_fd(s->manager);
402 setsockopt(fd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP, &mreq, sizeof(mreq));
404 if (setsockopt(fd, IPPROTO_IPV6, b ? IPV6_ADD_MEMBERSHIP : IPV6_DROP_MEMBERSHIP, &mreq, sizeof(mreq)) < 0)
407 return -EAFNOSUPPORT;
412 int dns_scope_good_dns_server(DnsScope *s, int family, const union in_addr_union *address) {
416 if (s->protocol != DNS_PROTOCOL_DNS)
420 return !!link_find_dns_server(s->link, family, address);
422 return !!manager_find_dns_server(s->manager, family, address);
425 static int dns_scope_make_reply_packet(
435 _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
442 if ((!q || q->n_keys <= 0)
443 && (!answer || answer->n_rrs <= 0)
444 && (!soa || soa->n_rrs <= 0))
447 r = dns_packet_new(&p, s->protocol, 0);
451 DNS_PACKET_HEADER(p)->id = id;
452 DNS_PACKET_HEADER(p)->flags = htobe16(DNS_PACKET_MAKE_FLAGS(
464 for (i = 0; i < q->n_keys; i++) {
465 r = dns_packet_append_key(p, q->keys[i], NULL);
470 DNS_PACKET_HEADER(p)->qdcount = htobe16(q->n_keys);
474 for (i = 0; i < answer->n_rrs; i++) {
475 r = dns_packet_append_rr(p, answer->rrs[i], NULL);
480 DNS_PACKET_HEADER(p)->ancount = htobe16(answer->n_rrs);
484 for (i = 0; i < soa->n_rrs; i++) {
485 r = dns_packet_append_rr(p, soa->rrs[i], NULL);
490 DNS_PACKET_HEADER(p)->arcount = htobe16(soa->n_rrs);
499 static void dns_scope_verify_conflicts(DnsScope *s, DnsPacket *p) {
506 for (n = 0; n < p->question->n_keys; n++)
507 dns_zone_verify_conflicts(&s->zone, p->question->keys[n]);
509 for (n = 0; n < p->answer->n_rrs; n++)
510 dns_zone_verify_conflicts(&s->zone, p->answer->rrs[n]->key);
513 void dns_scope_process_query(DnsScope *s, DnsStream *stream, DnsPacket *p) {
514 _cleanup_(dns_packet_unrefp) DnsPacket *reply = NULL;
515 _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL, *soa = NULL;
516 bool tentative = false;
522 if (p->protocol != DNS_PROTOCOL_LLMNR)
525 if (p->ipproto == IPPROTO_UDP) {
526 /* Don't accept UDP queries directed to anything but
527 * the LLMNR multicast addresses. See RFC 4795,
530 if (p->family == AF_INET && !in_addr_equal(AF_INET, &p->destination, (union in_addr_union*) &LLMNR_MULTICAST_IPV4_ADDRESS))
533 if (p->family == AF_INET6 && !in_addr_equal(AF_INET6, &p->destination, (union in_addr_union*) &LLMNR_MULTICAST_IPV6_ADDRESS))
537 r = dns_packet_extract(p);
539 log_debug("Failed to extract resources from incoming packet: %s", strerror(-r));
543 if (DNS_PACKET_C(p)) {
544 /* Somebody notified us about a possible conflict */
545 dns_scope_verify_conflicts(s, p);
549 r = dns_zone_lookup(&s->zone, p->question, &answer, &soa, &tentative);
551 log_debug("Failed to lookup key: %s", strerror(-r));
558 dns_answer_order_by_scope(answer, in_addr_is_link_local(p->family, &p->sender) > 0);
560 r = dns_scope_make_reply_packet(s, DNS_PACKET_ID(p), DNS_RCODE_SUCCESS, p->question, answer, soa, tentative, &reply);
562 log_debug("Failed to build reply packet: %s", strerror(-r));
567 r = dns_stream_write_packet(stream, reply);
569 if (!ratelimit_test(&s->ratelimit))
572 if (p->family == AF_INET)
573 fd = manager_llmnr_ipv4_udp_fd(s->manager);
574 else if (p->family == AF_INET6)
575 fd = manager_llmnr_ipv6_udp_fd(s->manager);
577 log_debug("Unknown protocol");
581 log_debug("Failed to get reply socket: %s", strerror(-fd));
585 /* Note that we always immediately reply to all LLMNR
586 * requests, and do not wait any time, since we
587 * verified uniqueness for all records. Also see RFC
588 * 4795, Section 2.7 */
590 r = manager_send(s->manager, fd, p->ifindex, p->family, &p->sender, p->sender_port, reply);
594 log_debug("Failed to send reply packet: %s", strerror(-r));
599 DnsTransaction *dns_scope_find_transaction(DnsScope *scope, DnsQuestion *question, bool cache_ok) {
605 /* Try to find an ongoing transaction that is a equal or a
606 * superset of the specified question */
608 LIST_FOREACH(transactions_by_scope, t, scope->transactions) {
610 /* Refuse reusing transactions that completed based on
611 * cached data instead of a real packet, if that's
614 IN_SET(t->state, DNS_TRANSACTION_SUCCESS, DNS_TRANSACTION_FAILURE) &&
618 if (dns_question_is_superset(t->question, question) > 0)
625 static int dns_scope_make_conflict_packet(
627 DnsResourceRecord *rr,
630 _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
637 r = dns_packet_new(&p, s->protocol, 0);
641 DNS_PACKET_HEADER(p)->flags = htobe16(DNS_PACKET_MAKE_FLAGS(
651 random_bytes(&DNS_PACKET_HEADER(p)->id, sizeof(uint16_t));
652 DNS_PACKET_HEADER(p)->qdcount = htobe16(1);
653 DNS_PACKET_HEADER(p)->arcount = htobe16(1);
655 r = dns_packet_append_key(p, rr->key, NULL);
659 r = dns_packet_append_rr(p, rr, NULL);
669 static int on_conflict_dispatch(sd_event_source *es, usec_t usec, void *userdata) {
670 DnsScope *scope = userdata;
676 scope->conflict_event_source = sd_event_source_unref(scope->conflict_event_source);
679 _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
680 _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
682 rr = hashmap_steal_first(scope->conflict_queue);
686 r = dns_scope_make_conflict_packet(scope, rr, &p);
688 log_error("Failed to make conflict packet: %s", strerror(-r));
692 r = dns_scope_emit(scope, p);
694 log_debug("Failed to send conflict packet: %s", strerror(-r));
700 int dns_scope_notify_conflict(DnsScope *scope, DnsResourceRecord *rr) {
707 /* We don't send these queries immediately. Instead, we queue
708 * them, and send them after some jitter delay. */
709 r = hashmap_ensure_allocated(&scope->conflict_queue, dns_resource_key_hash_func, dns_resource_key_compare_func);
715 /* We only place one RR per key in the conflict
716 * messages, not all of them. That should be enough to
717 * indicate where there might be a conflict */
718 r = hashmap_put(scope->conflict_queue, rr->key, rr);
719 if (r == -EEXIST || r == 0)
722 log_debug("Failed to queue conflicting RR: %s", strerror(-r));
726 dns_resource_record_ref(rr);
728 if (scope->conflict_event_source)
731 random_bytes(&jitter, sizeof(jitter));
732 jitter %= LLMNR_JITTER_INTERVAL_USEC;
734 r = sd_event_add_time(scope->manager->event,
735 &scope->conflict_event_source,
736 clock_boottime_or_monotonic(),
737 now(clock_boottime_or_monotonic()) + jitter,
738 LLMNR_JITTER_INTERVAL_USEC,
739 on_conflict_dispatch, scope);
741 log_debug("Failed to add conflict dispatch event: %s", strerror(-r));
748 void dns_scope_check_conflicts(DnsScope *scope, DnsPacket *p) {
755 if (p->protocol != DNS_PROTOCOL_LLMNR)
758 if (DNS_PACKET_RRCOUNT(p) <= 0)
761 if (DNS_PACKET_C(p) != 0)
764 if (DNS_PACKET_T(p) != 0)
767 if (manager_our_packet(scope->manager, p))
770 r = dns_packet_extract(p);
772 log_debug("Failed to extract packet: %s", strerror(-r));
776 log_debug("Checking for conflicts...");
778 for (i = 0; i < p->answer->n_rrs; i++) {
780 /* Check for conflicts against the local zone. If we
781 * found one, we won't check any further */
782 r = dns_zone_check_conflicts(&scope->zone, p->answer->rrs[i]);
786 /* Check for conflicts against the local cache. If so,
787 * send out an advisory query, to inform everybody */
788 r = dns_cache_check_conflicts(&scope->cache, p->answer->rrs[i], p->family, &p->sender);
792 dns_scope_notify_conflict(scope, p->answer->rrs[i]);