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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 | ||
0dd25fb9 | 31 | int dns_scope_new(Manager *m, DnsScope **ret, Link *l, DnsProtocol protocol, int family) { |
74b2466e LP |
32 | DnsScope *s; |
33 | ||
34 | assert(m); | |
35 | assert(ret); | |
36 | ||
37 | s = new0(DnsScope, 1); | |
38 | if (!s) | |
39 | return -ENOMEM; | |
40 | ||
41 | s->manager = m; | |
1716f6dc LP |
42 | s->link = l; |
43 | s->protocol = protocol; | |
44 | s->family = family; | |
74b2466e LP |
45 | |
46 | LIST_PREPEND(scopes, m->dns_scopes, s); | |
47 | ||
1716f6dc LP |
48 | dns_scope_llmnr_membership(s, true); |
49 | ||
46f08bea | 50 | 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 | 51 | |
74b2466e LP |
52 | *ret = s; |
53 | return 0; | |
54 | } | |
55 | ||
56 | DnsScope* dns_scope_free(DnsScope *s) { | |
ec2c5e43 | 57 | DnsTransaction *t; |
faa133f3 | 58 | |
74b2466e LP |
59 | if (!s) |
60 | return NULL; | |
61 | ||
46f08bea | 62 | 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 |
63 | |
64 | dns_scope_llmnr_membership(s, false); | |
65 | ||
faa133f3 LP |
66 | while ((t = s->transactions)) { |
67 | ||
68 | /* Abort the transaction, but make sure it is not | |
69 | * freed while we still look at it */ | |
74b2466e | 70 | |
faa133f3 | 71 | t->block_gc++; |
ec2c5e43 | 72 | dns_transaction_complete(t, DNS_TRANSACTION_ABORTED); |
faa133f3 | 73 | t->block_gc--; |
74b2466e | 74 | |
ec2c5e43 | 75 | dns_transaction_free(t); |
74b2466e LP |
76 | } |
77 | ||
322345fd | 78 | dns_cache_flush(&s->cache); |
623a4c97 | 79 | dns_zone_flush(&s->zone); |
322345fd | 80 | |
74b2466e LP |
81 | LIST_REMOVE(scopes, s->manager->dns_scopes, s); |
82 | strv_free(s->domains); | |
83 | free(s); | |
84 | ||
85 | return NULL; | |
86 | } | |
87 | ||
88 | DnsServer *dns_scope_get_server(DnsScope *s) { | |
89 | assert(s); | |
90 | ||
1716f6dc LP |
91 | if (s->protocol != DNS_PROTOCOL_DNS) |
92 | return NULL; | |
93 | ||
74b2466e LP |
94 | if (s->link) |
95 | return link_get_dns_server(s->link); | |
96 | else | |
97 | return manager_get_dns_server(s->manager); | |
98 | } | |
99 | ||
100 | void dns_scope_next_dns_server(DnsScope *s) { | |
101 | assert(s); | |
102 | ||
1716f6dc LP |
103 | if (s->protocol != DNS_PROTOCOL_DNS) |
104 | return; | |
105 | ||
74b2466e LP |
106 | if (s->link) |
107 | link_next_dns_server(s->link); | |
108 | else | |
109 | manager_next_dns_server(s->manager); | |
110 | } | |
111 | ||
112 | int dns_scope_send(DnsScope *s, DnsPacket *p) { | |
1716f6dc LP |
113 | union in_addr_union addr; |
114 | int ifindex = 0, r; | |
0dd25fb9 | 115 | int family; |
1716f6dc LP |
116 | uint16_t port; |
117 | uint32_t mtu; | |
118 | int fd; | |
74b2466e LP |
119 | |
120 | assert(s); | |
121 | assert(p); | |
1716f6dc | 122 | assert(p->protocol == s->protocol); |
ad867662 LP |
123 | |
124 | if (s->link) { | |
1716f6dc | 125 | mtu = s->link->mtu; |
74b2466e | 126 | ifindex = s->link->ifindex; |
1716f6dc | 127 | } else |
e1c95994 | 128 | mtu = manager_find_mtu(s->manager); |
74b2466e | 129 | |
1716f6dc LP |
130 | if (s->protocol == DNS_PROTOCOL_DNS) { |
131 | DnsServer *srv; | |
e1c95994 | 132 | |
623a4c97 LP |
133 | if (DNS_PACKET_QDCOUNT(p) > 1) |
134 | return -ENOTSUP; | |
135 | ||
1716f6dc LP |
136 | srv = dns_scope_get_server(s); |
137 | if (!srv) | |
138 | return -ESRCH; | |
139 | ||
140 | family = srv->family; | |
141 | addr = srv->address; | |
142 | port = 53; | |
143 | ||
144 | if (p->size > DNS_PACKET_UNICAST_SIZE_MAX) | |
145 | return -EMSGSIZE; | |
146 | ||
147 | if (p->size > mtu) | |
148 | return -EMSGSIZE; | |
149 | ||
150 | if (family == AF_INET) | |
151 | fd = manager_dns_ipv4_fd(s->manager); | |
152 | else if (family == AF_INET6) | |
153 | fd = manager_dns_ipv6_fd(s->manager); | |
154 | else | |
155 | return -EAFNOSUPPORT; | |
156 | if (fd < 0) | |
157 | return fd; | |
158 | ||
159 | } else if (s->protocol == DNS_PROTOCOL_LLMNR) { | |
160 | ||
161 | if (DNS_PACKET_QDCOUNT(p) > 1) | |
162 | return -ENOTSUP; | |
163 | ||
164 | family = s->family; | |
165 | port = 5355; | |
166 | ||
167 | if (family == AF_INET) { | |
168 | addr.in = LLMNR_MULTICAST_IPV4_ADDRESS; | |
1716f6dc LP |
169 | fd = manager_llmnr_ipv4_udp_fd(s->manager); |
170 | } else if (family == AF_INET6) { | |
171 | addr.in6 = LLMNR_MULTICAST_IPV6_ADDRESS; | |
172 | fd = manager_llmnr_ipv6_udp_fd(s->manager); | |
1716f6dc LP |
173 | } else |
174 | return -EAFNOSUPPORT; | |
175 | if (fd < 0) | |
176 | return fd; | |
177 | } else | |
74b2466e LP |
178 | return -EAFNOSUPPORT; |
179 | ||
1716f6dc | 180 | r = manager_send(s->manager, fd, ifindex, family, &addr, port, p); |
74b2466e LP |
181 | if (r < 0) |
182 | return r; | |
183 | ||
184 | return 1; | |
185 | } | |
186 | ||
623a4c97 | 187 | int dns_scope_tcp_socket(DnsScope *s, int family, const union in_addr_union *address, uint16_t port) { |
ad867662 LP |
188 | _cleanup_close_ int fd = -1; |
189 | union sockaddr_union sa = {}; | |
190 | socklen_t salen; | |
623a4c97 LP |
191 | static const int one = 1; |
192 | int ret, r; | |
ad867662 LP |
193 | |
194 | assert(s); | |
623a4c97 | 195 | assert((family == AF_UNSPEC) == !address); |
ad867662 | 196 | |
623a4c97 LP |
197 | if (family == AF_UNSPEC) { |
198 | DnsServer *srv; | |
199 | ||
200 | srv = dns_scope_get_server(s); | |
201 | if (!srv) | |
202 | return -ESRCH; | |
203 | ||
204 | sa.sa.sa_family = srv->family; | |
205 | if (srv->family == AF_INET) { | |
206 | sa.in.sin_port = htobe16(port); | |
207 | sa.in.sin_addr = srv->address.in; | |
208 | salen = sizeof(sa.in); | |
209 | } else if (srv->family == AF_INET6) { | |
210 | sa.in6.sin6_port = htobe16(port); | |
211 | sa.in6.sin6_addr = srv->address.in6; | |
212 | sa.in6.sin6_scope_id = s->link ? s->link->ifindex : 0; | |
213 | salen = sizeof(sa.in6); | |
214 | } else | |
215 | return -EAFNOSUPPORT; | |
216 | } else { | |
217 | sa.sa.sa_family = family; | |
218 | ||
219 | if (family == AF_INET) { | |
220 | sa.in.sin_port = htobe16(port); | |
221 | sa.in.sin_addr = address->in; | |
222 | salen = sizeof(sa.in); | |
223 | } else if (family == AF_INET6) { | |
224 | sa.in6.sin6_port = htobe16(port); | |
225 | sa.in6.sin6_addr = address->in6; | |
226 | sa.in6.sin6_scope_id = s->link ? s->link->ifindex : 0; | |
227 | salen = sizeof(sa.in6); | |
228 | } else | |
229 | return -EAFNOSUPPORT; | |
230 | } | |
ad867662 | 231 | |
623a4c97 | 232 | fd = socket(sa.sa.sa_family, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); |
ad867662 LP |
233 | if (fd < 0) |
234 | return -errno; | |
235 | ||
623a4c97 LP |
236 | r = setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &one, sizeof(one)); |
237 | if (r < 0) | |
238 | return -errno; | |
239 | ||
240 | if (s->link) { | |
241 | uint32_t ifindex = htobe32(s->link->ifindex); | |
242 | ||
243 | if (sa.sa.sa_family == AF_INET) { | |
244 | r = setsockopt(fd, IPPROTO_IP, IP_UNICAST_IF, &ifindex, sizeof(ifindex)); | |
245 | if (r < 0) | |
246 | return -errno; | |
247 | } else if (sa.sa.sa_family == AF_INET6) { | |
248 | r = setsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_IF, &ifindex, sizeof(ifindex)); | |
249 | if (r < 0) | |
250 | return -errno; | |
251 | } | |
252 | } | |
253 | ||
254 | if (s->protocol == DNS_PROTOCOL_LLMNR) { | |
bf3f1271 | 255 | /* RFC 4795, section 2.5 requires the TTL to be set to 1 */ |
623a4c97 LP |
256 | |
257 | if (sa.sa.sa_family == AF_INET) { | |
258 | r = setsockopt(fd, IPPROTO_IP, IP_TTL, &one, sizeof(one)); | |
259 | if (r < 0) | |
260 | return -errno; | |
261 | } else if (sa.sa.sa_family == AF_INET6) { | |
262 | r = setsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &one, sizeof(one)); | |
263 | if (r < 0) | |
264 | return -errno; | |
265 | } | |
266 | } | |
ad867662 LP |
267 | |
268 | r = connect(fd, &sa.sa, salen); | |
269 | if (r < 0 && errno != EINPROGRESS) | |
270 | return -errno; | |
271 | ||
272 | ret = fd; | |
273 | fd = -1; | |
623a4c97 | 274 | |
ad867662 LP |
275 | return ret; |
276 | } | |
277 | ||
1716f6dc | 278 | DnsScopeMatch dns_scope_good_domain(DnsScope *s, const char *domain) { |
74b2466e LP |
279 | char **i; |
280 | ||
281 | assert(s); | |
282 | assert(domain); | |
283 | ||
284 | STRV_FOREACH(i, s->domains) | |
faa133f3 | 285 | if (dns_name_endswith(domain, *i) > 0) |
74b2466e LP |
286 | return DNS_SCOPE_YES; |
287 | ||
faa133f3 | 288 | if (dns_name_root(domain) != 0) |
74b2466e LP |
289 | return DNS_SCOPE_NO; |
290 | ||
faec72d5 LP |
291 | if (is_localhost(domain)) |
292 | return DNS_SCOPE_NO; | |
293 | ||
1716f6dc | 294 | if (s->protocol == DNS_PROTOCOL_DNS) { |
faa133f3 LP |
295 | if (dns_name_endswith(domain, "254.169.in-addr.arpa") == 0 && |
296 | dns_name_endswith(domain, "0.8.e.f.ip6.arpa") == 0 && | |
297 | dns_name_single_label(domain) == 0) | |
298 | return DNS_SCOPE_MAYBE; | |
1716f6dc | 299 | |
faa133f3 | 300 | return DNS_SCOPE_NO; |
1716f6dc LP |
301 | } |
302 | ||
303 | if (s->protocol == DNS_PROTOCOL_MDNS) { | |
faa133f3 LP |
304 | if (dns_name_endswith(domain, "254.169.in-addr.arpa") > 0 || |
305 | dns_name_endswith(domain, "0.8.e.f.ip6.arpa") > 0 || | |
306 | (dns_name_endswith(domain, "local") > 0 && dns_name_equal(domain, "local") == 0)) | |
74b2466e LP |
307 | return DNS_SCOPE_MAYBE; |
308 | ||
309 | return DNS_SCOPE_NO; | |
310 | } | |
311 | ||
1716f6dc | 312 | if (s->protocol == DNS_PROTOCOL_LLMNR) { |
b914e211 LP |
313 | if (dns_name_endswith(domain, "in-addr.arpa") > 0 || |
314 | dns_name_endswith(domain, "ip6.arpa") > 0 || | |
faa133f3 | 315 | dns_name_single_label(domain) > 0) |
1716f6dc | 316 | return DNS_SCOPE_MAYBE; |
74b2466e | 317 | |
1716f6dc | 318 | return DNS_SCOPE_NO; |
74b2466e LP |
319 | } |
320 | ||
1716f6dc LP |
321 | assert_not_reached("Unknown scope protocol"); |
322 | } | |
323 | ||
324 | int dns_scope_good_key(DnsScope *s, DnsResourceKey *key) { | |
325 | assert(s); | |
326 | assert(key); | |
327 | ||
328 | if (s->protocol == DNS_PROTOCOL_DNS) | |
329 | return true; | |
330 | ||
331 | /* On mDNS and LLMNR, send A and AAAA queries only on the | |
332 | * respective scopes */ | |
333 | ||
334 | if (s->family == AF_INET && key->class == DNS_CLASS_IN && key->type == DNS_TYPE_AAAA) | |
335 | return false; | |
336 | ||
337 | if (s->family == AF_INET6 && key->class == DNS_CLASS_IN && key->type == DNS_TYPE_A) | |
338 | return false; | |
339 | ||
340 | return true; | |
341 | } | |
342 | ||
343 | int dns_scope_llmnr_membership(DnsScope *s, bool b) { | |
344 | int fd; | |
345 | ||
346 | if (s->family == AF_INET) { | |
347 | struct ip_mreqn mreqn = { | |
348 | .imr_multiaddr = LLMNR_MULTICAST_IPV4_ADDRESS, | |
349 | .imr_ifindex = s->link->ifindex, | |
350 | }; | |
351 | ||
352 | fd = manager_llmnr_ipv4_udp_fd(s->manager); | |
353 | if (fd < 0) | |
354 | return fd; | |
355 | ||
356 | if (setsockopt(fd, IPPROTO_IP, b ? IP_ADD_MEMBERSHIP : IP_DROP_MEMBERSHIP, &mreqn, sizeof(mreqn)) < 0) | |
357 | return -errno; | |
358 | ||
359 | } else if (s->family == AF_INET6) { | |
360 | struct ipv6_mreq mreq = { | |
361 | .ipv6mr_multiaddr = LLMNR_MULTICAST_IPV6_ADDRESS, | |
362 | .ipv6mr_interface = s->link->ifindex, | |
363 | }; | |
364 | ||
365 | fd = manager_llmnr_ipv6_udp_fd(s->manager); | |
366 | if (fd < 0) | |
367 | return fd; | |
368 | ||
369 | if (setsockopt(fd, IPPROTO_IPV6, b ? IPV6_ADD_MEMBERSHIP : IPV6_DROP_MEMBERSHIP, &mreq, sizeof(mreq)) < 0) | |
370 | return -errno; | |
371 | } else | |
372 | return -EAFNOSUPPORT; | |
373 | ||
374 | return 0; | |
74b2466e | 375 | } |
623a4c97 LP |
376 | |
377 | int dns_scope_good_dns_server(DnsScope *s, int family, const union in_addr_union *address) { | |
378 | assert(s); | |
379 | assert(address); | |
380 | ||
381 | if (s->protocol != DNS_PROTOCOL_DNS) | |
382 | return 1; | |
383 | ||
384 | if (s->link) | |
385 | return !!link_find_dns_server(s->link, family, address); | |
386 | else | |
387 | return !!manager_find_dns_server(s->manager, family, address); | |
388 | } | |
389 | ||
ec2c5e43 LP |
390 | static int dns_scope_make_reply_packet( |
391 | DnsScope *s, | |
392 | uint16_t id, | |
393 | int rcode, | |
394 | DnsQuestion *q, | |
395 | DnsAnswer *answer, | |
396 | DnsAnswer *soa, | |
397 | bool tentative, | |
398 | DnsPacket **ret) { | |
399 | ||
623a4c97 LP |
400 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; |
401 | unsigned i; | |
402 | int r; | |
403 | ||
404 | assert(s); | |
405 | ||
8bf52d3d | 406 | if (q->n_keys <= 0 && answer->n_rrs <= 0 && soa->n_rrs <= 0) |
623a4c97 LP |
407 | return -EINVAL; |
408 | ||
409 | r = dns_packet_new(&p, s->protocol, 0); | |
410 | if (r < 0) | |
411 | return r; | |
412 | ||
413 | DNS_PACKET_HEADER(p)->id = id; | |
ea917db9 LP |
414 | DNS_PACKET_HEADER(p)->flags = htobe16(DNS_PACKET_MAKE_FLAGS( |
415 | 1 /* qr */, | |
416 | 0 /* opcode */, | |
417 | 0 /* c */, | |
418 | 0 /* tc */, | |
ec2c5e43 | 419 | tentative, |
ea917db9 LP |
420 | 0 /* (ra) */, |
421 | 0 /* (ad) */, | |
422 | 0 /* (cd) */, | |
423 | rcode)); | |
623a4c97 LP |
424 | |
425 | if (q) { | |
426 | for (i = 0; i < q->n_keys; i++) { | |
427 | r = dns_packet_append_key(p, q->keys[i], NULL); | |
428 | if (r < 0) | |
429 | return r; | |
430 | } | |
431 | ||
432 | DNS_PACKET_HEADER(p)->qdcount = htobe16(q->n_keys); | |
433 | } | |
434 | ||
8bf52d3d LP |
435 | if (answer) { |
436 | for (i = 0; i < answer->n_rrs; i++) { | |
437 | r = dns_packet_append_rr(p, answer->rrs[i], NULL); | |
623a4c97 LP |
438 | if (r < 0) |
439 | return r; | |
440 | } | |
441 | ||
8bf52d3d LP |
442 | DNS_PACKET_HEADER(p)->ancount = htobe16(answer->n_rrs); |
443 | } | |
444 | ||
445 | if (soa) { | |
446 | for (i = 0; i < soa->n_rrs; i++) { | |
447 | r = dns_packet_append_rr(p, soa->rrs[i], NULL); | |
448 | if (r < 0) | |
449 | return r; | |
450 | } | |
451 | ||
452 | DNS_PACKET_HEADER(p)->arcount = htobe16(soa->n_rrs); | |
623a4c97 LP |
453 | } |
454 | ||
455 | *ret = p; | |
456 | p = NULL; | |
457 | ||
458 | return 0; | |
459 | } | |
460 | ||
461 | void dns_scope_process_query(DnsScope *s, DnsStream *stream, DnsPacket *p) { | |
462 | _cleanup_(dns_packet_unrefp) DnsPacket *reply = NULL; | |
8bf52d3d | 463 | _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL, *soa = NULL; |
ec2c5e43 | 464 | bool tentative = false; |
623a4c97 LP |
465 | int r, fd; |
466 | ||
467 | assert(s); | |
468 | assert(p); | |
469 | ||
470 | if (p->protocol != DNS_PROTOCOL_LLMNR) | |
471 | return; | |
472 | ||
2442b93d LP |
473 | if (p->ipproto == IPPROTO_UDP) { |
474 | /* Don't accept UDP queries directed to anything but | |
475 | * the LLMNR multicast addresses. See RFC 4795, | |
476 | * section 2.5.*/ | |
477 | ||
478 | if (p->family == AF_INET && !in_addr_equal(AF_INET, &p->destination, (union in_addr_union*) &LLMNR_MULTICAST_IPV4_ADDRESS)) | |
479 | return; | |
480 | ||
481 | if (p->family == AF_INET6 && !in_addr_equal(AF_INET6, &p->destination, (union in_addr_union*) &LLMNR_MULTICAST_IPV6_ADDRESS)) | |
482 | return; | |
483 | } | |
484 | ||
623a4c97 LP |
485 | r = dns_packet_extract(p); |
486 | if (r < 0) { | |
487 | log_debug("Failed to extract resources from incoming packet: %s", strerror(-r)); | |
488 | return; | |
489 | } | |
490 | ||
ea917db9 LP |
491 | if (DNS_PACKET_C(p)) { |
492 | /* FIXME: Somebody notified us about a likely conflict */ | |
493 | return; | |
494 | } | |
495 | ||
ec2c5e43 | 496 | r = dns_zone_lookup(&s->zone, p->question, &answer, &soa, &tentative); |
623a4c97 LP |
497 | if (r < 0) { |
498 | log_debug("Failed to lookup key: %s", strerror(-r)); | |
499 | return; | |
500 | } | |
501 | if (r == 0) | |
502 | return; | |
503 | ||
fcf57f9c LP |
504 | if (answer) |
505 | dns_answer_order_by_scope(answer, in_addr_is_link_local(p->family, &p->sender) > 0); | |
af93291c | 506 | |
ec2c5e43 | 507 | r = dns_scope_make_reply_packet(s, DNS_PACKET_ID(p), DNS_RCODE_SUCCESS, p->question, answer, soa, tentative, &reply); |
623a4c97 LP |
508 | if (r < 0) { |
509 | log_debug("Failed to build reply packet: %s", strerror(-r)); | |
510 | return; | |
511 | } | |
512 | ||
513 | if (stream) | |
514 | r = dns_stream_write_packet(stream, reply); | |
515 | else { | |
516 | if (p->family == AF_INET) | |
517 | fd = manager_llmnr_ipv4_udp_fd(s->manager); | |
518 | else if (p->family == AF_INET6) | |
519 | fd = manager_llmnr_ipv6_udp_fd(s->manager); | |
520 | else { | |
521 | log_debug("Unknown protocol"); | |
522 | return; | |
523 | } | |
524 | if (fd < 0) { | |
525 | log_debug("Failed to get reply socket: %s", strerror(-fd)); | |
526 | return; | |
527 | } | |
528 | ||
529 | r = manager_send(s->manager, fd, p->ifindex, p->family, &p->sender, p->sender_port, reply); | |
530 | } | |
531 | ||
532 | if (r < 0) { | |
533 | log_debug("Failed to send reply packet: %s", strerror(-r)); | |
534 | return; | |
535 | } | |
536 | } | |
ec2c5e43 LP |
537 | |
538 | DnsTransaction *dns_scope_find_transaction(DnsScope *scope, DnsQuestion *question) { | |
539 | DnsTransaction *t; | |
540 | ||
541 | assert(scope); | |
542 | assert(question); | |
543 | ||
544 | /* Try to find an ongoing transaction that is a equal or a | |
545 | * superset of the specified question */ | |
546 | ||
547 | LIST_FOREACH(transactions_by_scope, t, scope->transactions) | |
548 | if (dns_question_is_superset(t->question, question) > 0) | |
549 | return t; | |
550 | ||
551 | return NULL; | |
552 | } |