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74b2466e LP |
1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright 2014 Lennart Poettering | |
7 | ||
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. | |
12 | ||
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. | |
17 | ||
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/>. | |
20 | ***/ | |
21 | ||
ad867662 LP |
22 | #include <netinet/tcp.h> |
23 | ||
623a4c97 | 24 | #include "missing.h" |
74b2466e | 25 | #include "strv.h" |
ad867662 | 26 | #include "socket-util.h" |
46f08bea | 27 | #include "af-list.h" |
74b2466e LP |
28 | #include "resolved-dns-domain.h" |
29 | #include "resolved-dns-scope.h" | |
30 | ||
aea2429d LP |
31 | #define MULTICAST_RATELIMIT_INTERVAL_USEC (1*USEC_PER_SEC) |
32 | #define MULTICAST_RATELIMIT_BURST 1000 | |
33 | ||
0dd25fb9 | 34 | int dns_scope_new(Manager *m, DnsScope **ret, Link *l, DnsProtocol protocol, int family) { |
74b2466e LP |
35 | DnsScope *s; |
36 | ||
37 | assert(m); | |
38 | assert(ret); | |
39 | ||
40 | s = new0(DnsScope, 1); | |
41 | if (!s) | |
42 | return -ENOMEM; | |
43 | ||
44 | s->manager = m; | |
1716f6dc LP |
45 | s->link = l; |
46 | s->protocol = protocol; | |
47 | s->family = family; | |
74b2466e LP |
48 | |
49 | LIST_PREPEND(scopes, m->dns_scopes, s); | |
50 | ||
1716f6dc LP |
51 | dns_scope_llmnr_membership(s, true); |
52 | ||
46f08bea | 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)); |
1716f6dc | 54 | |
aea2429d LP |
55 | /* Enforce ratelimiting for the multicast protocols */ |
56 | RATELIMIT_INIT(s->ratelimit, MULTICAST_RATELIMIT_INTERVAL_USEC, MULTICAST_RATELIMIT_BURST); | |
57 | ||
74b2466e LP |
58 | *ret = s; |
59 | return 0; | |
60 | } | |
61 | ||
62 | DnsScope* dns_scope_free(DnsScope *s) { | |
ec2c5e43 | 63 | DnsTransaction *t; |
a4076574 | 64 | DnsResourceRecord *rr; |
faa133f3 | 65 | |
74b2466e LP |
66 | if (!s) |
67 | return NULL; | |
68 | ||
46f08bea | 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)); |
1716f6dc LP |
70 | |
71 | dns_scope_llmnr_membership(s, false); | |
72 | ||
faa133f3 LP |
73 | while ((t = s->transactions)) { |
74 | ||
75 | /* Abort the transaction, but make sure it is not | |
76 | * freed while we still look at it */ | |
74b2466e | 77 | |
faa133f3 | 78 | t->block_gc++; |
ec2c5e43 | 79 | dns_transaction_complete(t, DNS_TRANSACTION_ABORTED); |
faa133f3 | 80 | t->block_gc--; |
74b2466e | 81 | |
ec2c5e43 | 82 | dns_transaction_free(t); |
74b2466e LP |
83 | } |
84 | ||
a4076574 LP |
85 | while ((rr = hashmap_steal_first(s->conflict_queue))) |
86 | dns_resource_record_unref(rr); | |
87 | ||
88 | hashmap_free(s->conflict_queue); | |
89 | sd_event_source_unref(s->conflict_event_source); | |
90 | ||
322345fd | 91 | dns_cache_flush(&s->cache); |
623a4c97 | 92 | dns_zone_flush(&s->zone); |
322345fd | 93 | |
74b2466e LP |
94 | LIST_REMOVE(scopes, s->manager->dns_scopes, s); |
95 | strv_free(s->domains); | |
96 | free(s); | |
97 | ||
98 | return NULL; | |
99 | } | |
100 | ||
2c27fbca | 101 | DnsServer *dns_scope_get_dns_server(DnsScope *s) { |
74b2466e LP |
102 | assert(s); |
103 | ||
1716f6dc LP |
104 | if (s->protocol != DNS_PROTOCOL_DNS) |
105 | return NULL; | |
106 | ||
74b2466e LP |
107 | if (s->link) |
108 | return link_get_dns_server(s->link); | |
109 | else | |
110 | return manager_get_dns_server(s->manager); | |
111 | } | |
112 | ||
113 | void dns_scope_next_dns_server(DnsScope *s) { | |
114 | assert(s); | |
115 | ||
1716f6dc LP |
116 | if (s->protocol != DNS_PROTOCOL_DNS) |
117 | return; | |
118 | ||
74b2466e LP |
119 | if (s->link) |
120 | link_next_dns_server(s->link); | |
121 | else | |
122 | manager_next_dns_server(s->manager); | |
123 | } | |
124 | ||
a4076574 | 125 | int dns_scope_emit(DnsScope *s, DnsPacket *p) { |
1716f6dc LP |
126 | union in_addr_union addr; |
127 | int ifindex = 0, r; | |
0dd25fb9 | 128 | int family; |
1716f6dc LP |
129 | uint16_t port; |
130 | uint32_t mtu; | |
131 | int fd; | |
74b2466e LP |
132 | |
133 | assert(s); | |
134 | assert(p); | |
1716f6dc | 135 | assert(p->protocol == s->protocol); |
ad867662 LP |
136 | |
137 | if (s->link) { | |
1716f6dc | 138 | mtu = s->link->mtu; |
74b2466e | 139 | ifindex = s->link->ifindex; |
1716f6dc | 140 | } else |
e1c95994 | 141 | mtu = manager_find_mtu(s->manager); |
74b2466e | 142 | |
1716f6dc LP |
143 | if (s->protocol == DNS_PROTOCOL_DNS) { |
144 | DnsServer *srv; | |
e1c95994 | 145 | |
623a4c97 LP |
146 | if (DNS_PACKET_QDCOUNT(p) > 1) |
147 | return -ENOTSUP; | |
148 | ||
2c27fbca | 149 | srv = dns_scope_get_dns_server(s); |
1716f6dc LP |
150 | if (!srv) |
151 | return -ESRCH; | |
152 | ||
153 | family = srv->family; | |
154 | addr = srv->address; | |
155 | port = 53; | |
156 | ||
157 | if (p->size > DNS_PACKET_UNICAST_SIZE_MAX) | |
158 | return -EMSGSIZE; | |
159 | ||
160 | if (p->size > mtu) | |
161 | return -EMSGSIZE; | |
162 | ||
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); | |
167 | else | |
168 | return -EAFNOSUPPORT; | |
169 | if (fd < 0) | |
170 | return fd; | |
171 | ||
172 | } else if (s->protocol == DNS_PROTOCOL_LLMNR) { | |
173 | ||
174 | if (DNS_PACKET_QDCOUNT(p) > 1) | |
175 | return -ENOTSUP; | |
176 | ||
aea2429d LP |
177 | if (!ratelimit_test(&s->ratelimit)) |
178 | return -EBUSY; | |
179 | ||
1716f6dc LP |
180 | family = s->family; |
181 | port = 5355; | |
182 | ||
183 | if (family == AF_INET) { | |
184 | addr.in = LLMNR_MULTICAST_IPV4_ADDRESS; | |
1716f6dc LP |
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); | |
1716f6dc LP |
189 | } else |
190 | return -EAFNOSUPPORT; | |
191 | if (fd < 0) | |
192 | return fd; | |
193 | } else | |
74b2466e LP |
194 | return -EAFNOSUPPORT; |
195 | ||
1716f6dc | 196 | r = manager_send(s->manager, fd, ifindex, family, &addr, port, p); |
74b2466e LP |
197 | if (r < 0) |
198 | return r; | |
199 | ||
200 | return 1; | |
201 | } | |
202 | ||
623a4c97 | 203 | int dns_scope_tcp_socket(DnsScope *s, int family, const union in_addr_union *address, uint16_t port) { |
ad867662 LP |
204 | _cleanup_close_ int fd = -1; |
205 | union sockaddr_union sa = {}; | |
206 | socklen_t salen; | |
623a4c97 LP |
207 | static const int one = 1; |
208 | int ret, r; | |
ad867662 LP |
209 | |
210 | assert(s); | |
623a4c97 | 211 | assert((family == AF_UNSPEC) == !address); |
ad867662 | 212 | |
623a4c97 LP |
213 | if (family == AF_UNSPEC) { |
214 | DnsServer *srv; | |
215 | ||
2c27fbca | 216 | srv = dns_scope_get_dns_server(s); |
623a4c97 LP |
217 | if (!srv) |
218 | return -ESRCH; | |
219 | ||
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); | |
230 | } else | |
231 | return -EAFNOSUPPORT; | |
232 | } else { | |
233 | sa.sa.sa_family = family; | |
234 | ||
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); | |
244 | } else | |
245 | return -EAFNOSUPPORT; | |
246 | } | |
ad867662 | 247 | |
623a4c97 | 248 | fd = socket(sa.sa.sa_family, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); |
ad867662 LP |
249 | if (fd < 0) |
250 | return -errno; | |
251 | ||
623a4c97 LP |
252 | r = setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &one, sizeof(one)); |
253 | if (r < 0) | |
254 | return -errno; | |
255 | ||
256 | if (s->link) { | |
257 | uint32_t ifindex = htobe32(s->link->ifindex); | |
258 | ||
259 | if (sa.sa.sa_family == AF_INET) { | |
260 | r = setsockopt(fd, IPPROTO_IP, IP_UNICAST_IF, &ifindex, sizeof(ifindex)); | |
261 | if (r < 0) | |
262 | return -errno; | |
263 | } else if (sa.sa.sa_family == AF_INET6) { | |
264 | r = setsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_IF, &ifindex, sizeof(ifindex)); | |
265 | if (r < 0) | |
266 | return -errno; | |
267 | } | |
268 | } | |
269 | ||
270 | if (s->protocol == DNS_PROTOCOL_LLMNR) { | |
bf3f1271 | 271 | /* RFC 4795, section 2.5 requires the TTL to be set to 1 */ |
623a4c97 LP |
272 | |
273 | if (sa.sa.sa_family == AF_INET) { | |
274 | r = setsockopt(fd, IPPROTO_IP, IP_TTL, &one, sizeof(one)); | |
275 | if (r < 0) | |
276 | return -errno; | |
277 | } else if (sa.sa.sa_family == AF_INET6) { | |
278 | r = setsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &one, sizeof(one)); | |
279 | if (r < 0) | |
280 | return -errno; | |
281 | } | |
282 | } | |
ad867662 LP |
283 | |
284 | r = connect(fd, &sa.sa, salen); | |
285 | if (r < 0 && errno != EINPROGRESS) | |
286 | return -errno; | |
287 | ||
288 | ret = fd; | |
289 | fd = -1; | |
623a4c97 | 290 | |
ad867662 LP |
291 | return ret; |
292 | } | |
293 | ||
51323288 | 294 | DnsScopeMatch dns_scope_good_domain(DnsScope *s, int ifindex, uint64_t flags, const char *domain) { |
74b2466e LP |
295 | char **i; |
296 | ||
297 | assert(s); | |
298 | assert(domain); | |
299 | ||
51323288 LP |
300 | if (ifindex != 0 && (!s->link || s->link->ifindex != ifindex)) |
301 | return DNS_SCOPE_NO; | |
302 | ||
303 | if ((SD_RESOLVED_FLAGS_MAKE(s->protocol, s->family) & flags) == 0) | |
304 | return DNS_SCOPE_NO; | |
305 | ||
74b2466e | 306 | STRV_FOREACH(i, s->domains) |
faa133f3 | 307 | if (dns_name_endswith(domain, *i) > 0) |
74b2466e LP |
308 | return DNS_SCOPE_YES; |
309 | ||
faa133f3 | 310 | if (dns_name_root(domain) != 0) |
74b2466e LP |
311 | return DNS_SCOPE_NO; |
312 | ||
faec72d5 LP |
313 | if (is_localhost(domain)) |
314 | return DNS_SCOPE_NO; | |
315 | ||
1716f6dc | 316 | if (s->protocol == DNS_PROTOCOL_DNS) { |
faa133f3 LP |
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; | |
1716f6dc | 321 | |
faa133f3 | 322 | return DNS_SCOPE_NO; |
1716f6dc LP |
323 | } |
324 | ||
325 | if (s->protocol == DNS_PROTOCOL_MDNS) { | |
faa133f3 LP |
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)) | |
74b2466e LP |
329 | return DNS_SCOPE_MAYBE; |
330 | ||
331 | return DNS_SCOPE_NO; | |
332 | } | |
333 | ||
1716f6dc | 334 | if (s->protocol == DNS_PROTOCOL_LLMNR) { |
b914e211 LP |
335 | if (dns_name_endswith(domain, "in-addr.arpa") > 0 || |
336 | dns_name_endswith(domain, "ip6.arpa") > 0 || | |
faa133f3 | 337 | dns_name_single_label(domain) > 0) |
1716f6dc | 338 | return DNS_SCOPE_MAYBE; |
74b2466e | 339 | |
1716f6dc | 340 | return DNS_SCOPE_NO; |
74b2466e LP |
341 | } |
342 | ||
1716f6dc LP |
343 | assert_not_reached("Unknown scope protocol"); |
344 | } | |
345 | ||
346 | int dns_scope_good_key(DnsScope *s, DnsResourceKey *key) { | |
347 | assert(s); | |
348 | assert(key); | |
349 | ||
350 | if (s->protocol == DNS_PROTOCOL_DNS) | |
351 | return true; | |
352 | ||
353 | /* On mDNS and LLMNR, send A and AAAA queries only on the | |
354 | * respective scopes */ | |
355 | ||
356 | if (s->family == AF_INET && key->class == DNS_CLASS_IN && key->type == DNS_TYPE_AAAA) | |
357 | return false; | |
358 | ||
359 | if (s->family == AF_INET6 && key->class == DNS_CLASS_IN && key->type == DNS_TYPE_A) | |
360 | return false; | |
361 | ||
362 | return true; | |
363 | } | |
364 | ||
365 | int dns_scope_llmnr_membership(DnsScope *s, bool b) { | |
366 | int fd; | |
367 | ||
368 | if (s->family == AF_INET) { | |
369 | struct ip_mreqn mreqn = { | |
370 | .imr_multiaddr = LLMNR_MULTICAST_IPV4_ADDRESS, | |
371 | .imr_ifindex = s->link->ifindex, | |
372 | }; | |
373 | ||
374 | fd = manager_llmnr_ipv4_udp_fd(s->manager); | |
375 | if (fd < 0) | |
376 | return fd; | |
377 | ||
7b4c2ee7 LP |
378 | /* Always first try to drop membership before we add |
379 | * one. This is necessary on some devices, such as | |
380 | * veth. */ | |
381 | if (b) | |
382 | setsockopt(fd, IPPROTO_IP, IP_DROP_MEMBERSHIP, &mreqn, sizeof(mreqn)); | |
383 | ||
1716f6dc LP |
384 | if (setsockopt(fd, IPPROTO_IP, b ? IP_ADD_MEMBERSHIP : IP_DROP_MEMBERSHIP, &mreqn, sizeof(mreqn)) < 0) |
385 | return -errno; | |
386 | ||
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, | |
391 | }; | |
392 | ||
393 | fd = manager_llmnr_ipv6_udp_fd(s->manager); | |
394 | if (fd < 0) | |
395 | return fd; | |
396 | ||
7b4c2ee7 LP |
397 | if (b) |
398 | setsockopt(fd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP, &mreq, sizeof(mreq)); | |
399 | ||
1716f6dc LP |
400 | if (setsockopt(fd, IPPROTO_IPV6, b ? IPV6_ADD_MEMBERSHIP : IPV6_DROP_MEMBERSHIP, &mreq, sizeof(mreq)) < 0) |
401 | return -errno; | |
402 | } else | |
403 | return -EAFNOSUPPORT; | |
404 | ||
405 | return 0; | |
74b2466e | 406 | } |
623a4c97 LP |
407 | |
408 | int dns_scope_good_dns_server(DnsScope *s, int family, const union in_addr_union *address) { | |
409 | assert(s); | |
410 | assert(address); | |
411 | ||
412 | if (s->protocol != DNS_PROTOCOL_DNS) | |
413 | return 1; | |
414 | ||
415 | if (s->link) | |
416 | return !!link_find_dns_server(s->link, family, address); | |
417 | else | |
2c27fbca | 418 | return !!manager_find_dns_server(s->manager, family, address); |
623a4c97 LP |
419 | } |
420 | ||
ec2c5e43 LP |
421 | static int dns_scope_make_reply_packet( |
422 | DnsScope *s, | |
423 | uint16_t id, | |
424 | int rcode, | |
425 | DnsQuestion *q, | |
426 | DnsAnswer *answer, | |
427 | DnsAnswer *soa, | |
428 | bool tentative, | |
429 | DnsPacket **ret) { | |
430 | ||
623a4c97 LP |
431 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; |
432 | unsigned i; | |
433 | int r; | |
434 | ||
435 | assert(s); | |
a4076574 | 436 | assert(ret); |
623a4c97 | 437 | |
75cd513e TA |
438 | if ((!q || q->n_keys <= 0) |
439 | && (!answer || answer->n_rrs <= 0) | |
440 | && (!soa || soa->n_rrs <= 0)) | |
623a4c97 LP |
441 | return -EINVAL; |
442 | ||
443 | r = dns_packet_new(&p, s->protocol, 0); | |
444 | if (r < 0) | |
445 | return r; | |
446 | ||
447 | DNS_PACKET_HEADER(p)->id = id; | |
ea917db9 LP |
448 | DNS_PACKET_HEADER(p)->flags = htobe16(DNS_PACKET_MAKE_FLAGS( |
449 | 1 /* qr */, | |
450 | 0 /* opcode */, | |
451 | 0 /* c */, | |
452 | 0 /* tc */, | |
ec2c5e43 | 453 | tentative, |
ea917db9 LP |
454 | 0 /* (ra) */, |
455 | 0 /* (ad) */, | |
456 | 0 /* (cd) */, | |
457 | rcode)); | |
623a4c97 LP |
458 | |
459 | if (q) { | |
460 | for (i = 0; i < q->n_keys; i++) { | |
461 | r = dns_packet_append_key(p, q->keys[i], NULL); | |
462 | if (r < 0) | |
463 | return r; | |
464 | } | |
465 | ||
466 | DNS_PACKET_HEADER(p)->qdcount = htobe16(q->n_keys); | |
467 | } | |
468 | ||
8bf52d3d LP |
469 | if (answer) { |
470 | for (i = 0; i < answer->n_rrs; i++) { | |
471 | r = dns_packet_append_rr(p, answer->rrs[i], NULL); | |
623a4c97 LP |
472 | if (r < 0) |
473 | return r; | |
474 | } | |
475 | ||
8bf52d3d LP |
476 | DNS_PACKET_HEADER(p)->ancount = htobe16(answer->n_rrs); |
477 | } | |
478 | ||
479 | if (soa) { | |
480 | for (i = 0; i < soa->n_rrs; i++) { | |
481 | r = dns_packet_append_rr(p, soa->rrs[i], NULL); | |
482 | if (r < 0) | |
483 | return r; | |
484 | } | |
485 | ||
486 | DNS_PACKET_HEADER(p)->arcount = htobe16(soa->n_rrs); | |
623a4c97 LP |
487 | } |
488 | ||
489 | *ret = p; | |
490 | p = NULL; | |
491 | ||
492 | return 0; | |
493 | } | |
494 | ||
a4076574 LP |
495 | static void dns_scope_verify_conflicts(DnsScope *s, DnsPacket *p) { |
496 | unsigned n; | |
497 | ||
498 | assert(s); | |
499 | assert(p); | |
500 | ||
501 | if (p->question) | |
502 | for (n = 0; n < p->question->n_keys; n++) | |
503 | dns_zone_verify_conflicts(&s->zone, p->question->keys[n]); | |
504 | if (p->answer) | |
505 | for (n = 0; n < p->answer->n_rrs; n++) | |
506 | dns_zone_verify_conflicts(&s->zone, p->answer->rrs[n]->key); | |
507 | } | |
508 | ||
623a4c97 LP |
509 | void dns_scope_process_query(DnsScope *s, DnsStream *stream, DnsPacket *p) { |
510 | _cleanup_(dns_packet_unrefp) DnsPacket *reply = NULL; | |
8bf52d3d | 511 | _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL, *soa = NULL; |
ec2c5e43 | 512 | bool tentative = false; |
623a4c97 LP |
513 | int r, fd; |
514 | ||
515 | assert(s); | |
516 | assert(p); | |
517 | ||
518 | if (p->protocol != DNS_PROTOCOL_LLMNR) | |
519 | return; | |
520 | ||
2442b93d LP |
521 | if (p->ipproto == IPPROTO_UDP) { |
522 | /* Don't accept UDP queries directed to anything but | |
523 | * the LLMNR multicast addresses. See RFC 4795, | |
524 | * section 2.5.*/ | |
525 | ||
526 | if (p->family == AF_INET && !in_addr_equal(AF_INET, &p->destination, (union in_addr_union*) &LLMNR_MULTICAST_IPV4_ADDRESS)) | |
527 | return; | |
528 | ||
529 | if (p->family == AF_INET6 && !in_addr_equal(AF_INET6, &p->destination, (union in_addr_union*) &LLMNR_MULTICAST_IPV6_ADDRESS)) | |
530 | return; | |
531 | } | |
532 | ||
623a4c97 LP |
533 | r = dns_packet_extract(p); |
534 | if (r < 0) { | |
535 | log_debug("Failed to extract resources from incoming packet: %s", strerror(-r)); | |
536 | return; | |
537 | } | |
538 | ||
ea917db9 | 539 | if (DNS_PACKET_C(p)) { |
a4076574 LP |
540 | /* Somebody notified us about a possible conflict */ |
541 | dns_scope_verify_conflicts(s, p); | |
ea917db9 LP |
542 | return; |
543 | } | |
544 | ||
ec2c5e43 | 545 | r = dns_zone_lookup(&s->zone, p->question, &answer, &soa, &tentative); |
623a4c97 LP |
546 | if (r < 0) { |
547 | log_debug("Failed to lookup key: %s", strerror(-r)); | |
548 | return; | |
549 | } | |
550 | if (r == 0) | |
551 | return; | |
552 | ||
fcf57f9c LP |
553 | if (answer) |
554 | dns_answer_order_by_scope(answer, in_addr_is_link_local(p->family, &p->sender) > 0); | |
af93291c | 555 | |
ec2c5e43 | 556 | r = dns_scope_make_reply_packet(s, DNS_PACKET_ID(p), DNS_RCODE_SUCCESS, p->question, answer, soa, tentative, &reply); |
623a4c97 LP |
557 | if (r < 0) { |
558 | log_debug("Failed to build reply packet: %s", strerror(-r)); | |
559 | return; | |
560 | } | |
561 | ||
562 | if (stream) | |
563 | r = dns_stream_write_packet(stream, reply); | |
564 | else { | |
aea2429d LP |
565 | if (!ratelimit_test(&s->ratelimit)) |
566 | return; | |
567 | ||
623a4c97 LP |
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); | |
572 | else { | |
573 | log_debug("Unknown protocol"); | |
574 | return; | |
575 | } | |
576 | if (fd < 0) { | |
577 | log_debug("Failed to get reply socket: %s", strerror(-fd)); | |
578 | return; | |
579 | } | |
580 | ||
6e068472 LP |
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 */ | |
585 | ||
623a4c97 LP |
586 | r = manager_send(s->manager, fd, p->ifindex, p->family, &p->sender, p->sender_port, reply); |
587 | } | |
588 | ||
589 | if (r < 0) { | |
590 | log_debug("Failed to send reply packet: %s", strerror(-r)); | |
591 | return; | |
592 | } | |
593 | } | |
ec2c5e43 | 594 | |
dc4d47e2 | 595 | DnsTransaction *dns_scope_find_transaction(DnsScope *scope, DnsQuestion *question, bool cache_ok) { |
ec2c5e43 LP |
596 | DnsTransaction *t; |
597 | ||
598 | assert(scope); | |
599 | assert(question); | |
600 | ||
601 | /* Try to find an ongoing transaction that is a equal or a | |
602 | * superset of the specified question */ | |
603 | ||
dc4d47e2 LP |
604 | LIST_FOREACH(transactions_by_scope, t, scope->transactions) { |
605 | ||
606 | /* Refuse reusing transactions that completed based on | |
607 | * cached data instead of a real packet, if that's | |
608 | * requested. */ | |
609 | if (!cache_ok && | |
610 | IN_SET(t->state, DNS_TRANSACTION_SUCCESS, DNS_TRANSACTION_FAILURE) && | |
611 | !t->received) | |
612 | continue; | |
613 | ||
ec2c5e43 LP |
614 | if (dns_question_is_superset(t->question, question) > 0) |
615 | return t; | |
dc4d47e2 | 616 | } |
ec2c5e43 LP |
617 | |
618 | return NULL; | |
619 | } | |
a4076574 LP |
620 | |
621 | static int dns_scope_make_conflict_packet( | |
622 | DnsScope *s, | |
623 | DnsResourceRecord *rr, | |
624 | DnsPacket **ret) { | |
625 | ||
626 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; | |
627 | int r; | |
628 | ||
629 | assert(s); | |
630 | assert(rr); | |
631 | assert(ret); | |
632 | ||
633 | r = dns_packet_new(&p, s->protocol, 0); | |
634 | if (r < 0) | |
635 | return r; | |
636 | ||
637 | DNS_PACKET_HEADER(p)->flags = htobe16(DNS_PACKET_MAKE_FLAGS( | |
638 | 0 /* qr */, | |
639 | 0 /* opcode */, | |
640 | 1 /* conflict */, | |
641 | 0 /* tc */, | |
642 | 0 /* t */, | |
643 | 0 /* (ra) */, | |
644 | 0 /* (ad) */, | |
645 | 0 /* (cd) */, | |
646 | 0)); | |
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); | |
650 | ||
651 | r = dns_packet_append_key(p, rr->key, NULL); | |
652 | if (r < 0) | |
653 | return r; | |
654 | ||
655 | r = dns_packet_append_rr(p, rr, NULL); | |
656 | if (r < 0) | |
657 | return r; | |
658 | ||
659 | *ret = p; | |
660 | p = NULL; | |
661 | ||
662 | return 0; | |
663 | } | |
664 | ||
665 | static int on_conflict_dispatch(sd_event_source *es, usec_t usec, void *userdata) { | |
666 | DnsScope *scope = userdata; | |
667 | int r; | |
668 | ||
669 | assert(es); | |
670 | assert(scope); | |
671 | ||
672 | scope->conflict_event_source = sd_event_source_unref(scope->conflict_event_source); | |
673 | ||
674 | for (;;) { | |
675 | _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL; | |
676 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; | |
677 | ||
678 | rr = hashmap_steal_first(scope->conflict_queue); | |
679 | if (!rr) | |
680 | break; | |
681 | ||
682 | r = dns_scope_make_conflict_packet(scope, rr, &p); | |
683 | if (r < 0) { | |
684 | log_error("Failed to make conflict packet: %s", strerror(-r)); | |
685 | return 0; | |
686 | } | |
687 | ||
688 | r = dns_scope_emit(scope, p); | |
689 | if (r < 0) | |
690 | log_debug("Failed to send conflict packet: %s", strerror(-r)); | |
691 | } | |
692 | ||
693 | return 0; | |
694 | } | |
695 | ||
696 | int dns_scope_notify_conflict(DnsScope *scope, DnsResourceRecord *rr) { | |
697 | usec_t jitter; | |
698 | int r; | |
699 | ||
700 | assert(scope); | |
701 | assert(rr); | |
702 | ||
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); | |
706 | if (r < 0) { | |
707 | log_oom(); | |
708 | return r; | |
709 | } | |
710 | ||
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) | |
716 | return 0; | |
717 | if (r < 0) { | |
718 | log_debug("Failed to queue conflicting RR: %s", strerror(-r)); | |
719 | return r; | |
720 | } | |
721 | ||
722 | dns_resource_record_ref(rr); | |
723 | ||
724 | if (scope->conflict_event_source) | |
725 | return 0; | |
726 | ||
727 | random_bytes(&jitter, sizeof(jitter)); | |
728 | jitter %= LLMNR_JITTER_INTERVAL_USEC; | |
729 | ||
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); | |
736 | if (r < 0) { | |
737 | log_debug("Failed to add conflict dispatch event: %s", strerror(-r)); | |
738 | return r; | |
739 | } | |
740 | ||
741 | return 0; | |
742 | } | |
743 | ||
744 | void dns_scope_check_conflicts(DnsScope *scope, DnsPacket *p) { | |
745 | unsigned i; | |
746 | int r; | |
747 | ||
748 | assert(scope); | |
749 | assert(p); | |
750 | ||
751 | if (p->protocol != DNS_PROTOCOL_LLMNR) | |
752 | return; | |
753 | ||
754 | if (DNS_PACKET_RRCOUNT(p) <= 0) | |
755 | return; | |
756 | ||
757 | if (DNS_PACKET_C(p) != 0) | |
758 | return; | |
759 | ||
760 | if (DNS_PACKET_T(p) != 0) | |
761 | return; | |
762 | ||
763 | if (manager_our_packet(scope->manager, p)) | |
764 | return; | |
765 | ||
766 | r = dns_packet_extract(p); | |
767 | if (r < 0) { | |
768 | log_debug("Failed to extract packet: %s", strerror(-r)); | |
769 | return; | |
770 | } | |
771 | ||
772 | log_debug("Checking for conflicts..."); | |
773 | ||
774 | for (i = 0; i < p->answer->n_rrs; i++) { | |
775 | ||
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]); | |
779 | if (r != 0) | |
780 | continue; | |
781 | ||
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); | |
785 | if (r <= 0) | |
786 | continue; | |
787 | ||
788 | dns_scope_notify_conflict(scope, p->answer->rrs[i]); | |
789 | } | |
790 | } |