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[thirdparty/systemd.git] / src / resolve / resolved-dns-scope.c
1 /* SPDX-License-Identifier: LGPL-2.1+ */
2
3 #include <netinet/tcp.h>
4
5 #include "af-list.h"
6 #include "alloc-util.h"
7 #include "dns-domain.h"
8 #include "fd-util.h"
9 #include "hostname-util.h"
10 #include "missing_network.h"
11 #include "random-util.h"
12 #include "resolved-dnssd.h"
13 #include "resolved-dns-scope.h"
14 #include "resolved-dns-zone.h"
15 #include "resolved-llmnr.h"
16 #include "resolved-mdns.h"
17 #include "socket-util.h"
18 #include "strv.h"
19
20 #define MULTICAST_RATELIMIT_INTERVAL_USEC (1*USEC_PER_SEC)
21 #define MULTICAST_RATELIMIT_BURST 1000
22
23 /* After how much time to repeat LLMNR requests, see RFC 4795 Section 7 */
24 #define MULTICAST_RESEND_TIMEOUT_MIN_USEC (100 * USEC_PER_MSEC)
25 #define MULTICAST_RESEND_TIMEOUT_MAX_USEC (1 * USEC_PER_SEC)
26
27 int dns_scope_new(Manager *m, DnsScope **ret, Link *l, DnsProtocol protocol, int family) {
28 DnsScope *s;
29
30 assert(m);
31 assert(ret);
32
33 s = new(DnsScope, 1);
34 if (!s)
35 return -ENOMEM;
36
37 *s = (DnsScope) {
38 .manager = m,
39 .link = l,
40 .protocol = protocol,
41 .family = family,
42 .resend_timeout = MULTICAST_RESEND_TIMEOUT_MIN_USEC,
43 };
44
45 if (protocol == DNS_PROTOCOL_DNS) {
46 /* Copy DNSSEC mode from the link if it is set there,
47 * otherwise take the manager's DNSSEC mode. Note that
48 * we copy this only at scope creation time, and do
49 * not update it from the on, even if the setting
50 * changes. */
51
52 if (l) {
53 s->dnssec_mode = link_get_dnssec_mode(l);
54 s->dns_over_tls_mode = link_get_dns_over_tls_mode(l);
55 } else {
56 s->dnssec_mode = manager_get_dnssec_mode(m);
57 s->dns_over_tls_mode = manager_get_dns_over_tls_mode(m);
58 }
59
60 } else {
61 s->dnssec_mode = DNSSEC_NO;
62 s->dns_over_tls_mode = DNS_OVER_TLS_NO;
63 }
64
65 LIST_PREPEND(scopes, m->dns_scopes, s);
66
67 dns_scope_llmnr_membership(s, true);
68 dns_scope_mdns_membership(s, true);
69
70 log_debug("New scope on link %s, protocol %s, family %s", l ? l->ifname : "*", dns_protocol_to_string(protocol), family == AF_UNSPEC ? "*" : af_to_name(family));
71
72 /* Enforce ratelimiting for the multicast protocols */
73 s->ratelimit = (RateLimit) { MULTICAST_RATELIMIT_INTERVAL_USEC, MULTICAST_RATELIMIT_BURST };
74
75 *ret = s;
76 return 0;
77 }
78
79 static void dns_scope_abort_transactions(DnsScope *s) {
80 assert(s);
81
82 while (s->transactions) {
83 DnsTransaction *t = s->transactions;
84
85 /* Abort the transaction, but make sure it is not
86 * freed while we still look at it */
87
88 t->block_gc++;
89 if (DNS_TRANSACTION_IS_LIVE(t->state))
90 dns_transaction_complete(t, DNS_TRANSACTION_ABORTED);
91 t->block_gc--;
92
93 dns_transaction_free(t);
94 }
95 }
96
97 DnsScope* dns_scope_free(DnsScope *s) {
98 if (!s)
99 return NULL;
100
101 log_debug("Removing scope on link %s, protocol %s, family %s", s->link ? s->link->ifname : "*", dns_protocol_to_string(s->protocol), s->family == AF_UNSPEC ? "*" : af_to_name(s->family));
102
103 dns_scope_llmnr_membership(s, false);
104 dns_scope_mdns_membership(s, false);
105 dns_scope_abort_transactions(s);
106
107 while (s->query_candidates)
108 dns_query_candidate_free(s->query_candidates);
109
110 hashmap_free(s->transactions_by_key);
111
112 ordered_hashmap_free_with_destructor(s->conflict_queue, dns_resource_record_unref);
113 sd_event_source_unref(s->conflict_event_source);
114
115 sd_event_source_unref(s->announce_event_source);
116
117 dns_cache_flush(&s->cache);
118 dns_zone_flush(&s->zone);
119
120 LIST_REMOVE(scopes, s->manager->dns_scopes, s);
121 return mfree(s);
122 }
123
124 DnsServer *dns_scope_get_dns_server(DnsScope *s) {
125 assert(s);
126
127 if (s->protocol != DNS_PROTOCOL_DNS)
128 return NULL;
129
130 if (s->link)
131 return link_get_dns_server(s->link);
132 else
133 return manager_get_dns_server(s->manager);
134 }
135
136 unsigned dns_scope_get_n_dns_servers(DnsScope *s) {
137 unsigned n = 0;
138 DnsServer *i;
139
140 assert(s);
141
142 if (s->protocol != DNS_PROTOCOL_DNS)
143 return 0;
144
145 if (s->link)
146 i = s->link->dns_servers;
147 else
148 i = s->manager->dns_servers;
149
150 for (; i; i = i->servers_next)
151 n++;
152
153 return n;
154 }
155
156 void dns_scope_next_dns_server(DnsScope *s) {
157 assert(s);
158
159 if (s->protocol != DNS_PROTOCOL_DNS)
160 return;
161
162 if (s->link)
163 link_next_dns_server(s->link);
164 else
165 manager_next_dns_server(s->manager);
166 }
167
168 void dns_scope_packet_received(DnsScope *s, usec_t rtt) {
169 assert(s);
170
171 if (rtt <= s->max_rtt)
172 return;
173
174 s->max_rtt = rtt;
175 s->resend_timeout = MIN(MAX(MULTICAST_RESEND_TIMEOUT_MIN_USEC, s->max_rtt * 2), MULTICAST_RESEND_TIMEOUT_MAX_USEC);
176 }
177
178 void dns_scope_packet_lost(DnsScope *s, usec_t usec) {
179 assert(s);
180
181 if (s->resend_timeout <= usec)
182 s->resend_timeout = MIN(s->resend_timeout * 2, MULTICAST_RESEND_TIMEOUT_MAX_USEC);
183 }
184
185 static int dns_scope_emit_one(DnsScope *s, int fd, DnsPacket *p) {
186 union in_addr_union addr;
187 int ifindex = 0, r;
188 int family;
189 uint32_t mtu;
190
191 assert(s);
192 assert(p);
193 assert(p->protocol == s->protocol);
194
195 if (s->link) {
196 mtu = s->link->mtu;
197 ifindex = s->link->ifindex;
198 } else
199 mtu = manager_find_mtu(s->manager);
200
201 switch (s->protocol) {
202
203 case DNS_PROTOCOL_DNS:
204 assert(fd >= 0);
205
206 if (DNS_PACKET_QDCOUNT(p) > 1)
207 return -EOPNOTSUPP;
208
209 if (p->size > DNS_PACKET_UNICAST_SIZE_MAX)
210 return -EMSGSIZE;
211
212 if (p->size + UDP_PACKET_HEADER_SIZE > mtu)
213 return -EMSGSIZE;
214
215 r = manager_write(s->manager, fd, p);
216 if (r < 0)
217 return r;
218
219 break;
220
221 case DNS_PROTOCOL_LLMNR:
222 assert(fd < 0);
223
224 if (DNS_PACKET_QDCOUNT(p) > 1)
225 return -EOPNOTSUPP;
226
227 if (!ratelimit_below(&s->ratelimit))
228 return -EBUSY;
229
230 family = s->family;
231
232 if (family == AF_INET) {
233 addr.in = LLMNR_MULTICAST_IPV4_ADDRESS;
234 fd = manager_llmnr_ipv4_udp_fd(s->manager);
235 } else if (family == AF_INET6) {
236 addr.in6 = LLMNR_MULTICAST_IPV6_ADDRESS;
237 fd = manager_llmnr_ipv6_udp_fd(s->manager);
238 } else
239 return -EAFNOSUPPORT;
240 if (fd < 0)
241 return fd;
242
243 r = manager_send(s->manager, fd, ifindex, family, &addr, LLMNR_PORT, NULL, p);
244 if (r < 0)
245 return r;
246
247 break;
248
249 case DNS_PROTOCOL_MDNS:
250 assert(fd < 0);
251
252 if (!ratelimit_below(&s->ratelimit))
253 return -EBUSY;
254
255 family = s->family;
256
257 if (family == AF_INET) {
258 addr.in = MDNS_MULTICAST_IPV4_ADDRESS;
259 fd = manager_mdns_ipv4_fd(s->manager);
260 } else if (family == AF_INET6) {
261 addr.in6 = MDNS_MULTICAST_IPV6_ADDRESS;
262 fd = manager_mdns_ipv6_fd(s->manager);
263 } else
264 return -EAFNOSUPPORT;
265 if (fd < 0)
266 return fd;
267
268 r = manager_send(s->manager, fd, ifindex, family, &addr, MDNS_PORT, NULL, p);
269 if (r < 0)
270 return r;
271
272 break;
273
274 default:
275 return -EAFNOSUPPORT;
276 }
277
278 return 1;
279 }
280
281 int dns_scope_emit_udp(DnsScope *s, int fd, DnsPacket *p) {
282 int r;
283
284 assert(s);
285 assert(p);
286 assert(p->protocol == s->protocol);
287 assert((s->protocol == DNS_PROTOCOL_DNS) == (fd >= 0));
288
289 do {
290 /* If there are multiple linked packets, set the TC bit in all but the last of them */
291 if (p->more) {
292 assert(p->protocol == DNS_PROTOCOL_MDNS);
293 dns_packet_set_flags(p, true, true);
294 }
295
296 r = dns_scope_emit_one(s, fd, p);
297 if (r < 0)
298 return r;
299
300 p = p->more;
301 } while (p);
302
303 return 0;
304 }
305
306 static int dns_scope_socket(
307 DnsScope *s,
308 int type,
309 int family,
310 const union in_addr_union *address,
311 DnsServer *server,
312 uint16_t port,
313 union sockaddr_union *ret_socket_address) {
314
315 _cleanup_close_ int fd = -1;
316 union sockaddr_union sa;
317 socklen_t salen;
318 int r, ifindex;
319
320 assert(s);
321
322 if (server) {
323 assert(family == AF_UNSPEC);
324 assert(!address);
325
326 ifindex = dns_server_ifindex(server);
327
328 switch (server->family) {
329 case AF_INET:
330 sa = (union sockaddr_union) {
331 .in.sin_family = server->family,
332 .in.sin_port = htobe16(port),
333 .in.sin_addr = server->address.in,
334 };
335 salen = sizeof(sa.in);
336 break;
337 case AF_INET6:
338 sa = (union sockaddr_union) {
339 .in6.sin6_family = server->family,
340 .in6.sin6_port = htobe16(port),
341 .in6.sin6_addr = server->address.in6,
342 .in6.sin6_scope_id = ifindex,
343 };
344 salen = sizeof(sa.in6);
345 break;
346 default:
347 return -EAFNOSUPPORT;
348 }
349 } else {
350 assert(family != AF_UNSPEC);
351 assert(address);
352
353 ifindex = s->link ? s->link->ifindex : 0;
354
355 switch (family) {
356 case AF_INET:
357 sa = (union sockaddr_union) {
358 .in.sin_family = family,
359 .in.sin_port = htobe16(port),
360 .in.sin_addr = address->in,
361 };
362 salen = sizeof(sa.in);
363 break;
364 case AF_INET6:
365 sa = (union sockaddr_union) {
366 .in6.sin6_family = family,
367 .in6.sin6_port = htobe16(port),
368 .in6.sin6_addr = address->in6,
369 .in6.sin6_scope_id = ifindex,
370 };
371 salen = sizeof(sa.in6);
372 break;
373 default:
374 return -EAFNOSUPPORT;
375 }
376 }
377
378 fd = socket(sa.sa.sa_family, type|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
379 if (fd < 0)
380 return -errno;
381
382 if (type == SOCK_STREAM) {
383 r = setsockopt_int(fd, IPPROTO_TCP, TCP_NODELAY, true);
384 if (r < 0)
385 return r;
386 }
387
388 if (s->link) {
389 be32_t ifindex_be = htobe32(ifindex);
390
391 if (sa.sa.sa_family == AF_INET) {
392 r = setsockopt(fd, IPPROTO_IP, IP_UNICAST_IF, &ifindex_be, sizeof(ifindex_be));
393 if (r < 0)
394 return -errno;
395 } else if (sa.sa.sa_family == AF_INET6) {
396 r = setsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_IF, &ifindex_be, sizeof(ifindex_be));
397 if (r < 0)
398 return -errno;
399 }
400 }
401
402 if (s->protocol == DNS_PROTOCOL_LLMNR) {
403 /* RFC 4795, section 2.5 requires the TTL to be set to 1 */
404
405 if (sa.sa.sa_family == AF_INET) {
406 r = setsockopt_int(fd, IPPROTO_IP, IP_TTL, true);
407 if (r < 0)
408 return r;
409 } else if (sa.sa.sa_family == AF_INET6) {
410 r = setsockopt_int(fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, true);
411 if (r < 0)
412 return r;
413 }
414 }
415
416 if (type == SOCK_DGRAM) {
417 /* Set IP_RECVERR or IPV6_RECVERR to get ICMP error feedback. See discussion in #10345. */
418
419 if (sa.sa.sa_family == AF_INET) {
420 r = setsockopt_int(fd, IPPROTO_IP, IP_RECVERR, true);
421 if (r < 0)
422 return r;
423
424 r = setsockopt_int(fd, IPPROTO_IP, IP_PKTINFO, true);
425 if (r < 0)
426 return r;
427
428 } else if (sa.sa.sa_family == AF_INET6) {
429 r = setsockopt_int(fd, IPPROTO_IPV6, IPV6_RECVERR, true);
430 if (r < 0)
431 return r;
432
433 r = setsockopt_int(fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, true);
434 if (r < 0)
435 return r;
436 }
437 }
438
439 if (ret_socket_address)
440 *ret_socket_address = sa;
441 else {
442 r = connect(fd, &sa.sa, salen);
443 if (r < 0 && errno != EINPROGRESS)
444 return -errno;
445 }
446
447 return TAKE_FD(fd);
448 }
449
450 int dns_scope_socket_udp(DnsScope *s, DnsServer *server) {
451 return dns_scope_socket(s, SOCK_DGRAM, AF_UNSPEC, NULL, server, dns_server_port(server), NULL);
452 }
453
454 int dns_scope_socket_tcp(DnsScope *s, int family, const union in_addr_union *address, DnsServer *server, uint16_t port, union sockaddr_union *ret_socket_address) {
455 /* If ret_socket_address is not NULL, the caller is responsible
456 * for calling connect() or sendmsg(). This is required by TCP
457 * Fast Open, to be able to send the initial SYN packet along
458 * with the first data packet. */
459 return dns_scope_socket(s, SOCK_STREAM, family, address, server, port, ret_socket_address);
460 }
461
462 static DnsScopeMatch accept_link_local_reverse_lookups(const char *domain) {
463 assert(domain);
464
465 if (dns_name_endswith(domain, "254.169.in-addr.arpa") > 0)
466 return DNS_SCOPE_YES_BASE + 4; /* 4 labels match */
467
468 if (dns_name_endswith(domain, "8.e.f.ip6.arpa") > 0 ||
469 dns_name_endswith(domain, "9.e.f.ip6.arpa") > 0 ||
470 dns_name_endswith(domain, "a.e.f.ip6.arpa") > 0 ||
471 dns_name_endswith(domain, "b.e.f.ip6.arpa") > 0)
472 return DNS_SCOPE_YES_BASE + 5; /* 5 labels match */
473
474 return _DNS_SCOPE_MATCH_INVALID;
475 }
476
477 DnsScopeMatch dns_scope_good_domain(
478 DnsScope *s,
479 int ifindex,
480 uint64_t flags,
481 const char *domain) {
482
483 DnsSearchDomain *d;
484
485 /* This returns the following return values:
486 *
487 * DNS_SCOPE_NO → This scope is not suitable for lookups of this domain, at all
488 * DNS_SCOPE_MAYBE → This scope is suitable, but only if nothing else wants it
489 * DNS_SCOPE_YES_BASE+n → This scope is suitable, and 'n' suffix labels match
490 *
491 * (The idea is that the caller will only use the scopes with the longest 'n' returned. If no scopes return
492 * DNS_SCOPE_YES_BASE+n, then it should use those which returned DNS_SCOPE_MAYBE. It should never use those
493 * which returned DNS_SCOPE_NO.)
494 */
495
496 assert(s);
497 assert(domain);
498
499 /* Checks if the specified domain is something to look up on this scope. Note that this accepts
500 * non-qualified hostnames, i.e. those without any search path suffixed. */
501
502 if (ifindex != 0 && (!s->link || s->link->ifindex != ifindex))
503 return DNS_SCOPE_NO;
504
505 if ((SD_RESOLVED_FLAGS_MAKE(s->protocol, s->family, 0) & flags) == 0)
506 return DNS_SCOPE_NO;
507
508 /* Never resolve any loopback hostname or IP address via DNS,
509 * LLMNR or mDNS. Instead, always rely on synthesized RRs for
510 * these. */
511 if (is_localhost(domain) ||
512 dns_name_endswith(domain, "127.in-addr.arpa") > 0 ||
513 dns_name_equal(domain, "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa") > 0)
514 return DNS_SCOPE_NO;
515
516 /* Never respond to some of the domains listed in RFC6303 */
517 if (dns_name_endswith(domain, "0.in-addr.arpa") > 0 ||
518 dns_name_equal(domain, "255.255.255.255.in-addr.arpa") > 0 ||
519 dns_name_equal(domain, "0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa") > 0)
520 return DNS_SCOPE_NO;
521
522 /* Never respond to some of the domains listed in RFC6761 */
523 if (dns_name_endswith(domain, "invalid") > 0)
524 return DNS_SCOPE_NO;
525
526 switch (s->protocol) {
527
528 case DNS_PROTOCOL_DNS: {
529 bool has_search_domains = false;
530 int n_best = -1;
531
532 /* Never route things to scopes that lack DNS servers */
533 if (!dns_scope_get_dns_server(s))
534 return DNS_SCOPE_NO;
535
536 /* Always honour search domains for routing queries, except if this scope lacks DNS servers. Note that
537 * we return DNS_SCOPE_YES here, rather than just DNS_SCOPE_MAYBE, which means other wildcard scopes
538 * won't be considered anymore. */
539 LIST_FOREACH(domains, d, dns_scope_get_search_domains(s)) {
540
541 if (!d->route_only && !dns_name_is_root(d->name))
542 has_search_domains = true;
543
544 if (dns_name_endswith(domain, d->name) > 0) {
545 int c;
546
547 c = dns_name_count_labels(d->name);
548 if (c < 0)
549 continue;
550
551 if (c > n_best)
552 n_best = c;
553 }
554 }
555
556 /* If there's a true search domain defined for this scope, and the query is single-label,
557 * then let's resolve things here, prefereably. Note that LLMNR considers itself
558 * authoritative for single-label names too, at the same preference, see below. */
559 if (has_search_domains && dns_name_is_single_label(domain))
560 return DNS_SCOPE_YES_BASE + 1;
561
562 /* Let's return the number of labels in the best matching result */
563 if (n_best >= 0) {
564 assert(n_best <= DNS_SCOPE_YES_END - DNS_SCOPE_YES_BASE);
565 return DNS_SCOPE_YES_BASE + n_best;
566 }
567
568 /* See if this scope is suitable as default route. */
569 if (!dns_scope_is_default_route(s))
570 return DNS_SCOPE_NO;
571
572 /* Exclude link-local IP ranges */
573 if (dns_name_endswith(domain, "254.169.in-addr.arpa") == 0 &&
574 dns_name_endswith(domain, "8.e.f.ip6.arpa") == 0 &&
575 dns_name_endswith(domain, "9.e.f.ip6.arpa") == 0 &&
576 dns_name_endswith(domain, "a.e.f.ip6.arpa") == 0 &&
577 dns_name_endswith(domain, "b.e.f.ip6.arpa") == 0 &&
578 /* If networks use .local in their private setups, they are supposed to also add .local to their search
579 * domains, which we already checked above. Otherwise, we consider .local specific to mDNS and won't
580 * send such queries ordinary DNS servers. */
581 dns_name_endswith(domain, "local") == 0)
582 return DNS_SCOPE_MAYBE;
583
584 return DNS_SCOPE_NO;
585 }
586
587 case DNS_PROTOCOL_MDNS: {
588 DnsScopeMatch m;
589
590 m = accept_link_local_reverse_lookups(domain);
591 if (m >= 0)
592 return m;
593
594 if ((s->family == AF_INET && dns_name_endswith(domain, "in-addr.arpa") > 0) ||
595 (s->family == AF_INET6 && dns_name_endswith(domain, "ip6.arpa") > 0))
596 return DNS_SCOPE_MAYBE;
597
598 if ((dns_name_endswith(domain, "local") > 0 && /* only resolve names ending in .local via mDNS */
599 dns_name_equal(domain, "local") == 0 && /* but not the single-label "local" name itself */
600 manager_is_own_hostname(s->manager, domain) <= 0)) /* never resolve the local hostname via mDNS */
601 return DNS_SCOPE_YES_BASE + 1; /* Return +1, as the top-level .local domain matches, i.e. one label */
602
603 return DNS_SCOPE_NO;
604 }
605
606 case DNS_PROTOCOL_LLMNR: {
607 DnsScopeMatch m;
608
609 m = accept_link_local_reverse_lookups(domain);
610 if (m >= 0)
611 return m;
612
613 if ((s->family == AF_INET && dns_name_endswith(domain, "in-addr.arpa") > 0) ||
614 (s->family == AF_INET6 && dns_name_endswith(domain, "ip6.arpa") > 0))
615 return DNS_SCOPE_MAYBE;
616
617 if ((dns_name_is_single_label(domain) && /* only resolve single label names via LLMNR */
618 !is_gateway_hostname(domain) && /* don't resolve "gateway" with LLMNR, let nss-myhostname handle this */
619 manager_is_own_hostname(s->manager, domain) <= 0)) /* never resolve the local hostname via LLMNR */
620 return DNS_SCOPE_YES_BASE + 1; /* Return +1, as we consider ourselves authoritative
621 * for single-label names, i.e. one label. This is
622 * particularly relevant as it means a "." route on some
623 * other scope won't pull all traffic away from
624 * us. (If people actually want to pull traffic away
625 * from us they should turn off LLMNR on the
626 * link). Note that unicast DNS scopes with search
627 * domains also consider themselves authoritative for
628 * single-label domains, at the same preference (see
629 * above). */
630
631 return DNS_SCOPE_NO;
632 }
633
634 default:
635 assert_not_reached("Unknown scope protocol");
636 }
637 }
638
639 bool dns_scope_good_key(DnsScope *s, const DnsResourceKey *key) {
640 int key_family;
641
642 assert(s);
643 assert(key);
644
645 /* Check if it makes sense to resolve the specified key on
646 * this scope. Note that this call assumes as fully qualified
647 * name, i.e. the search suffixes already appended. */
648
649 if (key->class != DNS_CLASS_IN)
650 return false;
651
652 if (s->protocol == DNS_PROTOCOL_DNS) {
653
654 /* On classic DNS, looking up non-address RRs is always fine. (Specifically, we want to
655 * permit looking up DNSKEY and DS records on the root and top-level domains.) */
656 if (!dns_resource_key_is_address(key))
657 return true;
658
659 /* Unless explicitly overridden, we refuse to look up A and AAAA RRs on the root and
660 * single-label domains, under the assumption that those should be resolved via LLMNR or
661 * search path only, and should not be leaked onto the internet. */
662 const char* name = dns_resource_key_name(key);
663
664 if (!s->manager->resolve_unicast_single_label &&
665 dns_name_is_single_label(name))
666 return false;
667
668 return !dns_name_is_root(name);
669 }
670
671 /* On mDNS and LLMNR, send A and AAAA queries only on the
672 * respective scopes */
673
674 key_family = dns_type_to_af(key->type);
675 if (key_family < 0)
676 return true;
677
678 return key_family == s->family;
679 }
680
681 static int dns_scope_multicast_membership(DnsScope *s, bool b, struct in_addr in, struct in6_addr in6) {
682 int fd;
683
684 assert(s);
685 assert(s->link);
686
687 if (s->family == AF_INET) {
688 struct ip_mreqn mreqn = {
689 .imr_multiaddr = in,
690 .imr_ifindex = s->link->ifindex,
691 };
692
693 if (s->protocol == DNS_PROTOCOL_LLMNR)
694 fd = manager_llmnr_ipv4_udp_fd(s->manager);
695 else
696 fd = manager_mdns_ipv4_fd(s->manager);
697
698 if (fd < 0)
699 return fd;
700
701 /* Always first try to drop membership before we add
702 * one. This is necessary on some devices, such as
703 * veth. */
704 if (b)
705 (void) setsockopt(fd, IPPROTO_IP, IP_DROP_MEMBERSHIP, &mreqn, sizeof(mreqn));
706
707 if (setsockopt(fd, IPPROTO_IP, b ? IP_ADD_MEMBERSHIP : IP_DROP_MEMBERSHIP, &mreqn, sizeof(mreqn)) < 0)
708 return -errno;
709
710 } else if (s->family == AF_INET6) {
711 struct ipv6_mreq mreq = {
712 .ipv6mr_multiaddr = in6,
713 .ipv6mr_interface = s->link->ifindex,
714 };
715
716 if (s->protocol == DNS_PROTOCOL_LLMNR)
717 fd = manager_llmnr_ipv6_udp_fd(s->manager);
718 else
719 fd = manager_mdns_ipv6_fd(s->manager);
720
721 if (fd < 0)
722 return fd;
723
724 if (b)
725 (void) setsockopt(fd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP, &mreq, sizeof(mreq));
726
727 if (setsockopt(fd, IPPROTO_IPV6, b ? IPV6_ADD_MEMBERSHIP : IPV6_DROP_MEMBERSHIP, &mreq, sizeof(mreq)) < 0)
728 return -errno;
729 } else
730 return -EAFNOSUPPORT;
731
732 return 0;
733 }
734
735 int dns_scope_llmnr_membership(DnsScope *s, bool b) {
736 assert(s);
737
738 if (s->protocol != DNS_PROTOCOL_LLMNR)
739 return 0;
740
741 return dns_scope_multicast_membership(s, b, LLMNR_MULTICAST_IPV4_ADDRESS, LLMNR_MULTICAST_IPV6_ADDRESS);
742 }
743
744 int dns_scope_mdns_membership(DnsScope *s, bool b) {
745 assert(s);
746
747 if (s->protocol != DNS_PROTOCOL_MDNS)
748 return 0;
749
750 return dns_scope_multicast_membership(s, b, MDNS_MULTICAST_IPV4_ADDRESS, MDNS_MULTICAST_IPV6_ADDRESS);
751 }
752
753 int dns_scope_make_reply_packet(
754 DnsScope *s,
755 uint16_t id,
756 int rcode,
757 DnsQuestion *q,
758 DnsAnswer *answer,
759 DnsAnswer *soa,
760 bool tentative,
761 DnsPacket **ret) {
762
763 _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
764 int r;
765
766 assert(s);
767 assert(ret);
768
769 if (dns_question_isempty(q) &&
770 dns_answer_isempty(answer) &&
771 dns_answer_isempty(soa))
772 return -EINVAL;
773
774 r = dns_packet_new(&p, s->protocol, 0, DNS_PACKET_SIZE_MAX);
775 if (r < 0)
776 return r;
777
778 DNS_PACKET_HEADER(p)->id = id;
779 DNS_PACKET_HEADER(p)->flags = htobe16(DNS_PACKET_MAKE_FLAGS(
780 1 /* qr */,
781 0 /* opcode */,
782 0 /* c */,
783 0 /* tc */,
784 tentative,
785 0 /* (ra) */,
786 0 /* (ad) */,
787 0 /* (cd) */,
788 rcode));
789
790 r = dns_packet_append_question(p, q);
791 if (r < 0)
792 return r;
793 DNS_PACKET_HEADER(p)->qdcount = htobe16(dns_question_size(q));
794
795 r = dns_packet_append_answer(p, answer);
796 if (r < 0)
797 return r;
798 DNS_PACKET_HEADER(p)->ancount = htobe16(dns_answer_size(answer));
799
800 r = dns_packet_append_answer(p, soa);
801 if (r < 0)
802 return r;
803 DNS_PACKET_HEADER(p)->arcount = htobe16(dns_answer_size(soa));
804
805 *ret = TAKE_PTR(p);
806
807 return 0;
808 }
809
810 static void dns_scope_verify_conflicts(DnsScope *s, DnsPacket *p) {
811 DnsResourceRecord *rr;
812 DnsResourceKey *key;
813
814 assert(s);
815 assert(p);
816
817 DNS_QUESTION_FOREACH(key, p->question)
818 dns_zone_verify_conflicts(&s->zone, key);
819
820 DNS_ANSWER_FOREACH(rr, p->answer)
821 dns_zone_verify_conflicts(&s->zone, rr->key);
822 }
823
824 void dns_scope_process_query(DnsScope *s, DnsStream *stream, DnsPacket *p) {
825 _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL, *soa = NULL;
826 _cleanup_(dns_packet_unrefp) DnsPacket *reply = NULL;
827 DnsResourceKey *key = NULL;
828 bool tentative = false;
829 int r;
830
831 assert(s);
832 assert(p);
833
834 if (p->protocol != DNS_PROTOCOL_LLMNR)
835 return;
836
837 if (p->ipproto == IPPROTO_UDP) {
838 /* Don't accept UDP queries directed to anything but
839 * the LLMNR multicast addresses. See RFC 4795,
840 * section 2.5. */
841
842 if (p->family == AF_INET && !in_addr_equal(AF_INET, &p->destination, (union in_addr_union*) &LLMNR_MULTICAST_IPV4_ADDRESS))
843 return;
844
845 if (p->family == AF_INET6 && !in_addr_equal(AF_INET6, &p->destination, (union in_addr_union*) &LLMNR_MULTICAST_IPV6_ADDRESS))
846 return;
847 }
848
849 r = dns_packet_extract(p);
850 if (r < 0) {
851 log_debug_errno(r, "Failed to extract resource records from incoming packet: %m");
852 return;
853 }
854
855 if (DNS_PACKET_LLMNR_C(p)) {
856 /* Somebody notified us about a possible conflict */
857 dns_scope_verify_conflicts(s, p);
858 return;
859 }
860
861 assert(dns_question_size(p->question) == 1);
862 key = p->question->keys[0];
863
864 r = dns_zone_lookup(&s->zone, key, 0, &answer, &soa, &tentative);
865 if (r < 0) {
866 log_debug_errno(r, "Failed to look up key: %m");
867 return;
868 }
869 if (r == 0)
870 return;
871
872 if (answer)
873 dns_answer_order_by_scope(answer, in_addr_is_link_local(p->family, &p->sender) > 0);
874
875 r = dns_scope_make_reply_packet(s, DNS_PACKET_ID(p), DNS_RCODE_SUCCESS, p->question, answer, soa, tentative, &reply);
876 if (r < 0) {
877 log_debug_errno(r, "Failed to build reply packet: %m");
878 return;
879 }
880
881 if (stream) {
882 r = dns_stream_write_packet(stream, reply);
883 if (r < 0) {
884 log_debug_errno(r, "Failed to enqueue reply packet: %m");
885 return;
886 }
887
888 /* Let's take an extra reference on this stream, so that it stays around after returning. The reference
889 * will be dangling until the stream is disconnected, and the default completion handler of the stream
890 * will then unref the stream and destroy it */
891 if (DNS_STREAM_QUEUED(stream))
892 dns_stream_ref(stream);
893 } else {
894 int fd;
895
896 if (!ratelimit_below(&s->ratelimit))
897 return;
898
899 if (p->family == AF_INET)
900 fd = manager_llmnr_ipv4_udp_fd(s->manager);
901 else if (p->family == AF_INET6)
902 fd = manager_llmnr_ipv6_udp_fd(s->manager);
903 else {
904 log_debug("Unknown protocol");
905 return;
906 }
907 if (fd < 0) {
908 log_debug_errno(fd, "Failed to get reply socket: %m");
909 return;
910 }
911
912 /* Note that we always immediately reply to all LLMNR
913 * requests, and do not wait any time, since we
914 * verified uniqueness for all records. Also see RFC
915 * 4795, Section 2.7 */
916
917 r = manager_send(s->manager, fd, p->ifindex, p->family, &p->sender, p->sender_port, NULL, reply);
918 if (r < 0) {
919 log_debug_errno(r, "Failed to send reply packet: %m");
920 return;
921 }
922 }
923 }
924
925 DnsTransaction *dns_scope_find_transaction(DnsScope *scope, DnsResourceKey *key, bool cache_ok) {
926 DnsTransaction *t;
927
928 assert(scope);
929 assert(key);
930
931 /* Try to find an ongoing transaction that is a equal to the
932 * specified question */
933 t = hashmap_get(scope->transactions_by_key, key);
934 if (!t)
935 return NULL;
936
937 /* Refuse reusing transactions that completed based on cached
938 * data instead of a real packet, if that's requested. */
939 if (!cache_ok &&
940 IN_SET(t->state, DNS_TRANSACTION_SUCCESS, DNS_TRANSACTION_RCODE_FAILURE) &&
941 t->answer_source != DNS_TRANSACTION_NETWORK)
942 return NULL;
943
944 return t;
945 }
946
947 static int dns_scope_make_conflict_packet(
948 DnsScope *s,
949 DnsResourceRecord *rr,
950 DnsPacket **ret) {
951
952 _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
953 int r;
954
955 assert(s);
956 assert(rr);
957 assert(ret);
958
959 r = dns_packet_new(&p, s->protocol, 0, DNS_PACKET_SIZE_MAX);
960 if (r < 0)
961 return r;
962
963 DNS_PACKET_HEADER(p)->flags = htobe16(DNS_PACKET_MAKE_FLAGS(
964 0 /* qr */,
965 0 /* opcode */,
966 1 /* conflict */,
967 0 /* tc */,
968 0 /* t */,
969 0 /* (ra) */,
970 0 /* (ad) */,
971 0 /* (cd) */,
972 0));
973
974 /* For mDNS, the transaction ID should always be 0 */
975 if (s->protocol != DNS_PROTOCOL_MDNS)
976 random_bytes(&DNS_PACKET_HEADER(p)->id, sizeof(uint16_t));
977
978 DNS_PACKET_HEADER(p)->qdcount = htobe16(1);
979 DNS_PACKET_HEADER(p)->arcount = htobe16(1);
980
981 r = dns_packet_append_key(p, rr->key, 0, NULL);
982 if (r < 0)
983 return r;
984
985 r = dns_packet_append_rr(p, rr, 0, NULL, NULL);
986 if (r < 0)
987 return r;
988
989 *ret = TAKE_PTR(p);
990
991 return 0;
992 }
993
994 static int on_conflict_dispatch(sd_event_source *es, usec_t usec, void *userdata) {
995 DnsScope *scope = userdata;
996 int r;
997
998 assert(es);
999 assert(scope);
1000
1001 scope->conflict_event_source = sd_event_source_unref(scope->conflict_event_source);
1002
1003 for (;;) {
1004 _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL;
1005 _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
1006 _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
1007
1008 key = ordered_hashmap_first_key(scope->conflict_queue);
1009 if (!key)
1010 break;
1011
1012 rr = ordered_hashmap_remove(scope->conflict_queue, key);
1013 assert(rr);
1014
1015 r = dns_scope_make_conflict_packet(scope, rr, &p);
1016 if (r < 0) {
1017 log_error_errno(r, "Failed to make conflict packet: %m");
1018 return 0;
1019 }
1020
1021 r = dns_scope_emit_udp(scope, -1, p);
1022 if (r < 0)
1023 log_debug_errno(r, "Failed to send conflict packet: %m");
1024 }
1025
1026 return 0;
1027 }
1028
1029 int dns_scope_notify_conflict(DnsScope *scope, DnsResourceRecord *rr) {
1030 usec_t jitter;
1031 int r;
1032
1033 assert(scope);
1034 assert(rr);
1035
1036 /* We don't send these queries immediately. Instead, we queue
1037 * them, and send them after some jitter delay. */
1038 r = ordered_hashmap_ensure_allocated(&scope->conflict_queue, &dns_resource_key_hash_ops);
1039 if (r < 0) {
1040 log_oom();
1041 return r;
1042 }
1043
1044 /* We only place one RR per key in the conflict
1045 * messages, not all of them. That should be enough to
1046 * indicate where there might be a conflict */
1047 r = ordered_hashmap_put(scope->conflict_queue, rr->key, rr);
1048 if (IN_SET(r, 0, -EEXIST))
1049 return 0;
1050 if (r < 0)
1051 return log_debug_errno(r, "Failed to queue conflicting RR: %m");
1052
1053 dns_resource_key_ref(rr->key);
1054 dns_resource_record_ref(rr);
1055
1056 if (scope->conflict_event_source)
1057 return 0;
1058
1059 random_bytes(&jitter, sizeof(jitter));
1060 jitter %= LLMNR_JITTER_INTERVAL_USEC;
1061
1062 r = sd_event_add_time(scope->manager->event,
1063 &scope->conflict_event_source,
1064 clock_boottime_or_monotonic(),
1065 now(clock_boottime_or_monotonic()) + jitter,
1066 LLMNR_JITTER_INTERVAL_USEC,
1067 on_conflict_dispatch, scope);
1068 if (r < 0)
1069 return log_debug_errno(r, "Failed to add conflict dispatch event: %m");
1070
1071 (void) sd_event_source_set_description(scope->conflict_event_source, "scope-conflict");
1072
1073 return 0;
1074 }
1075
1076 void dns_scope_check_conflicts(DnsScope *scope, DnsPacket *p) {
1077 DnsResourceRecord *rr;
1078 int r;
1079
1080 assert(scope);
1081 assert(p);
1082
1083 if (!IN_SET(p->protocol, DNS_PROTOCOL_LLMNR, DNS_PROTOCOL_MDNS))
1084 return;
1085
1086 if (DNS_PACKET_RRCOUNT(p) <= 0)
1087 return;
1088
1089 if (p->protocol == DNS_PROTOCOL_LLMNR) {
1090 if (DNS_PACKET_LLMNR_C(p) != 0)
1091 return;
1092
1093 if (DNS_PACKET_LLMNR_T(p) != 0)
1094 return;
1095 }
1096
1097 if (manager_our_packet(scope->manager, p))
1098 return;
1099
1100 r = dns_packet_extract(p);
1101 if (r < 0) {
1102 log_debug_errno(r, "Failed to extract packet: %m");
1103 return;
1104 }
1105
1106 log_debug("Checking for conflicts...");
1107
1108 DNS_ANSWER_FOREACH(rr, p->answer) {
1109 /* No conflict if it is DNS-SD RR used for service enumeration. */
1110 if (dns_resource_key_is_dnssd_ptr(rr->key))
1111 continue;
1112
1113 /* Check for conflicts against the local zone. If we
1114 * found one, we won't check any further */
1115 r = dns_zone_check_conflicts(&scope->zone, rr);
1116 if (r != 0)
1117 continue;
1118
1119 /* Check for conflicts against the local cache. If so,
1120 * send out an advisory query, to inform everybody */
1121 r = dns_cache_check_conflicts(&scope->cache, rr, p->family, &p->sender);
1122 if (r <= 0)
1123 continue;
1124
1125 dns_scope_notify_conflict(scope, rr);
1126 }
1127 }
1128
1129 void dns_scope_dump(DnsScope *s, FILE *f) {
1130 assert(s);
1131
1132 if (!f)
1133 f = stdout;
1134
1135 fputs("[Scope protocol=", f);
1136 fputs(dns_protocol_to_string(s->protocol), f);
1137
1138 if (s->link) {
1139 fputs(" interface=", f);
1140 fputs(s->link->ifname, f);
1141 }
1142
1143 if (s->family != AF_UNSPEC) {
1144 fputs(" family=", f);
1145 fputs(af_to_name(s->family), f);
1146 }
1147
1148 fputs("]\n", f);
1149
1150 if (!dns_zone_is_empty(&s->zone)) {
1151 fputs("ZONE:\n", f);
1152 dns_zone_dump(&s->zone, f);
1153 }
1154
1155 if (!dns_cache_is_empty(&s->cache)) {
1156 fputs("CACHE:\n", f);
1157 dns_cache_dump(&s->cache, f);
1158 }
1159 }
1160
1161 DnsSearchDomain *dns_scope_get_search_domains(DnsScope *s) {
1162 assert(s);
1163
1164 if (s->protocol != DNS_PROTOCOL_DNS)
1165 return NULL;
1166
1167 if (s->link)
1168 return s->link->search_domains;
1169
1170 return s->manager->search_domains;
1171 }
1172
1173 bool dns_scope_name_wants_search_domain(DnsScope *s, const char *name) {
1174 assert(s);
1175
1176 if (s->protocol != DNS_PROTOCOL_DNS)
1177 return false;
1178
1179 return dns_name_is_single_label(name);
1180 }
1181
1182 bool dns_scope_network_good(DnsScope *s) {
1183 /* Checks whether the network is in good state for lookups on this scope. For mDNS/LLMNR/Classic DNS scopes
1184 * bound to links this is easy, as they don't even exist if the link isn't in a suitable state. For the global
1185 * DNS scope we check whether there are any links that are up and have an address. */
1186
1187 if (s->link)
1188 return true;
1189
1190 return manager_routable(s->manager, AF_UNSPEC);
1191 }
1192
1193 int dns_scope_ifindex(DnsScope *s) {
1194 assert(s);
1195
1196 if (s->link)
1197 return s->link->ifindex;
1198
1199 return 0;
1200 }
1201
1202 static int on_announcement_timeout(sd_event_source *s, usec_t usec, void *userdata) {
1203 DnsScope *scope = userdata;
1204
1205 assert(s);
1206
1207 scope->announce_event_source = sd_event_source_unref(scope->announce_event_source);
1208
1209 (void) dns_scope_announce(scope, false);
1210 return 0;
1211 }
1212
1213 int dns_scope_announce(DnsScope *scope, bool goodbye) {
1214 _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
1215 _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
1216 _cleanup_set_free_ Set *types = NULL;
1217 DnsTransaction *t;
1218 DnsZoneItem *z, *i;
1219 unsigned size = 0;
1220 Iterator iterator;
1221 char *service_type;
1222 int r;
1223
1224 if (!scope)
1225 return 0;
1226
1227 if (scope->protocol != DNS_PROTOCOL_MDNS)
1228 return 0;
1229
1230 /* Check if we're done with probing. */
1231 LIST_FOREACH(transactions_by_scope, t, scope->transactions)
1232 if (DNS_TRANSACTION_IS_LIVE(t->state))
1233 return 0;
1234
1235 /* Check if there're services pending conflict resolution. */
1236 if (manager_next_dnssd_names(scope->manager))
1237 return 0; /* we reach this point only if changing hostname didn't help */
1238
1239 /* Calculate answer's size. */
1240 HASHMAP_FOREACH(z, scope->zone.by_key, iterator) {
1241 if (z->state != DNS_ZONE_ITEM_ESTABLISHED)
1242 continue;
1243
1244 if (z->rr->key->type == DNS_TYPE_PTR &&
1245 !dns_zone_contains_name(&scope->zone, z->rr->ptr.name)) {
1246 char key_str[DNS_RESOURCE_KEY_STRING_MAX];
1247
1248 log_debug("Skip PTR RR <%s> since its counterparts seem to be withdrawn", dns_resource_key_to_string(z->rr->key, key_str, sizeof key_str));
1249 z->state = DNS_ZONE_ITEM_WITHDRAWN;
1250 continue;
1251 }
1252
1253 /* Collect service types for _services._dns-sd._udp.local RRs in a set */
1254 if (!scope->announced &&
1255 dns_resource_key_is_dnssd_ptr(z->rr->key)) {
1256 if (!set_contains(types, dns_resource_key_name(z->rr->key))) {
1257 r = set_ensure_put(&types, &dns_name_hash_ops, dns_resource_key_name(z->rr->key));
1258 if (r < 0)
1259 return log_debug_errno(r, "Failed to add item to set: %m");
1260 }
1261 }
1262
1263 LIST_FOREACH(by_key, i, z)
1264 size++;
1265 }
1266
1267 answer = dns_answer_new(size + set_size(types));
1268 if (!answer)
1269 return log_oom();
1270
1271 /* Second iteration, actually add RRs to the answer. */
1272 HASHMAP_FOREACH(z, scope->zone.by_key, iterator)
1273 LIST_FOREACH (by_key, i, z) {
1274 DnsAnswerFlags flags;
1275
1276 if (i->state != DNS_ZONE_ITEM_ESTABLISHED)
1277 continue;
1278
1279 if (dns_resource_key_is_dnssd_ptr(i->rr->key))
1280 flags = goodbye ? DNS_ANSWER_GOODBYE : 0;
1281 else
1282 flags = goodbye ? (DNS_ANSWER_GOODBYE|DNS_ANSWER_CACHE_FLUSH) : DNS_ANSWER_CACHE_FLUSH;
1283
1284 r = dns_answer_add(answer, i->rr, 0 , flags);
1285 if (r < 0)
1286 return log_debug_errno(r, "Failed to add RR to announce: %m");
1287 }
1288
1289 /* Since all the active services are in the zone make them discoverable now. */
1290 SET_FOREACH(service_type, types, iterator) {
1291 _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr;
1292
1293 rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_PTR,
1294 "_services._dns-sd._udp.local");
1295 rr->ptr.name = strdup(service_type);
1296 rr->ttl = MDNS_DEFAULT_TTL;
1297
1298 r = dns_zone_put(&scope->zone, scope, rr, false);
1299 if (r < 0)
1300 log_warning_errno(r, "Failed to add DNS-SD PTR record to MDNS zone: %m");
1301
1302 r = dns_answer_add(answer, rr, 0 , 0);
1303 if (r < 0)
1304 return log_debug_errno(r, "Failed to add RR to announce: %m");
1305 }
1306
1307 if (dns_answer_isempty(answer))
1308 return 0;
1309
1310 r = dns_scope_make_reply_packet(scope, 0, DNS_RCODE_SUCCESS, NULL, answer, NULL, false, &p);
1311 if (r < 0)
1312 return log_debug_errno(r, "Failed to build reply packet: %m");
1313
1314 r = dns_scope_emit_udp(scope, -1, p);
1315 if (r < 0)
1316 return log_debug_errno(r, "Failed to send reply packet: %m");
1317
1318 /* In section 8.3 of RFC6762: "The Multicast DNS responder MUST send at least two unsolicited
1319 * responses, one second apart." */
1320 if (!scope->announced) {
1321 usec_t ts;
1322
1323 scope->announced = true;
1324
1325 assert_se(sd_event_now(scope->manager->event, clock_boottime_or_monotonic(), &ts) >= 0);
1326 ts += MDNS_ANNOUNCE_DELAY;
1327
1328 r = sd_event_add_time(
1329 scope->manager->event,
1330 &scope->announce_event_source,
1331 clock_boottime_or_monotonic(),
1332 ts,
1333 MDNS_JITTER_RANGE_USEC,
1334 on_announcement_timeout, scope);
1335 if (r < 0)
1336 return log_debug_errno(r, "Failed to schedule second announcement: %m");
1337
1338 (void) sd_event_source_set_description(scope->announce_event_source, "mdns-announce");
1339 }
1340
1341 return 0;
1342 }
1343
1344 int dns_scope_add_dnssd_services(DnsScope *scope) {
1345 Iterator i;
1346 DnssdService *service;
1347 DnssdTxtData *txt_data;
1348 int r;
1349
1350 assert(scope);
1351
1352 if (hashmap_size(scope->manager->dnssd_services) == 0)
1353 return 0;
1354
1355 scope->announced = false;
1356
1357 HASHMAP_FOREACH(service, scope->manager->dnssd_services, i) {
1358 service->withdrawn = false;
1359
1360 r = dns_zone_put(&scope->zone, scope, service->ptr_rr, false);
1361 if (r < 0)
1362 log_warning_errno(r, "Failed to add PTR record to MDNS zone: %m");
1363
1364 r = dns_zone_put(&scope->zone, scope, service->srv_rr, true);
1365 if (r < 0)
1366 log_warning_errno(r, "Failed to add SRV record to MDNS zone: %m");
1367
1368 LIST_FOREACH(items, txt_data, service->txt_data_items) {
1369 r = dns_zone_put(&scope->zone, scope, txt_data->rr, true);
1370 if (r < 0)
1371 log_warning_errno(r, "Failed to add TXT record to MDNS zone: %m");
1372 }
1373 }
1374
1375 return 0;
1376 }
1377
1378 int dns_scope_remove_dnssd_services(DnsScope *scope) {
1379 _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL;
1380 Iterator i;
1381 DnssdService *service;
1382 DnssdTxtData *txt_data;
1383 int r;
1384
1385 assert(scope);
1386
1387 key = dns_resource_key_new(DNS_CLASS_IN, DNS_TYPE_PTR,
1388 "_services._dns-sd._udp.local");
1389 if (!key)
1390 return log_oom();
1391
1392 r = dns_zone_remove_rrs_by_key(&scope->zone, key);
1393 if (r < 0)
1394 return r;
1395
1396 HASHMAP_FOREACH(service, scope->manager->dnssd_services, i) {
1397 dns_zone_remove_rr(&scope->zone, service->ptr_rr);
1398 dns_zone_remove_rr(&scope->zone, service->srv_rr);
1399 LIST_FOREACH(items, txt_data, service->txt_data_items)
1400 dns_zone_remove_rr(&scope->zone, txt_data->rr);
1401 }
1402
1403 return 0;
1404 }
1405
1406 static bool dns_scope_has_route_only_domains(DnsScope *scope) {
1407 DnsSearchDomain *domain, *first;
1408 bool route_only = false;
1409
1410 assert(scope);
1411 assert(scope->protocol == DNS_PROTOCOL_DNS);
1412
1413 /* Returns 'true' if this scope is suitable for queries to specific domains only. For that we check
1414 * if there are any route-only domains on this interface, as a heuristic to discern VPN-style links
1415 * from non-VPN-style links. Returns 'false' for all other cases, i.e. if the scope is intended to
1416 * take queries to arbitrary domains, i.e. has no routing domains set. */
1417
1418 if (scope->link)
1419 first = scope->link->search_domains;
1420 else
1421 first = scope->manager->search_domains;
1422
1423 LIST_FOREACH(domains, domain, first) {
1424 /* "." means "any domain", thus the interface takes any kind of traffic. Thus, we exit early
1425 * here, as it doesn't really matter whether this link has any route-only domains or not,
1426 * "~." really trumps everything and clearly indicates that this interface shall receive all
1427 * traffic it can get. */
1428 if (dns_name_is_root(DNS_SEARCH_DOMAIN_NAME(domain)))
1429 return false;
1430
1431 if (domain->route_only)
1432 route_only = true;
1433 }
1434
1435 return route_only;
1436 }
1437
1438 bool dns_scope_is_default_route(DnsScope *scope) {
1439 assert(scope);
1440
1441 /* Only use DNS scopes as default routes */
1442 if (scope->protocol != DNS_PROTOCOL_DNS)
1443 return false;
1444
1445 /* The global DNS scope is always suitable as default route */
1446 if (!scope->link)
1447 return true;
1448
1449 /* Honour whatever is explicitly configured. This is really the best approach, and trumps any
1450 * automatic logic. */
1451 if (scope->link->default_route >= 0)
1452 return scope->link->default_route;
1453
1454 /* Otherwise check if we have any route-only domains, as a sensible heuristic: if so, let's not
1455 * volunteer as default route. */
1456 return !dns_scope_has_route_only_domains(scope);
1457 }
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