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ec2c5e43 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 | ||
22 | #include "af-list.h" | |
23 | ||
22a37591 | 24 | #include "resolved-llmnr.h" |
ec2c5e43 | 25 | #include "resolved-dns-transaction.h" |
3df3e884 | 26 | #include "random-util.h" |
ec2c5e43 LP |
27 | |
28 | DnsTransaction* dns_transaction_free(DnsTransaction *t) { | |
29 | DnsQuery *q; | |
30 | DnsZoneItem *i; | |
31 | ||
32 | if (!t) | |
33 | return NULL; | |
34 | ||
35 | sd_event_source_unref(t->timeout_event_source); | |
36 | ||
37 | dns_question_unref(t->question); | |
38 | dns_packet_unref(t->sent); | |
39 | dns_packet_unref(t->received); | |
40 | dns_answer_unref(t->cached); | |
41 | ||
42 | dns_stream_free(t->stream); | |
43 | ||
44 | if (t->scope) { | |
45 | LIST_REMOVE(transactions_by_scope, t->scope->transactions, t); | |
46 | ||
47 | if (t->id != 0) | |
48 | hashmap_remove(t->scope->manager->dns_transactions, UINT_TO_PTR(t->id)); | |
49 | } | |
50 | ||
51 | while ((q = set_steal_first(t->queries))) | |
52 | set_remove(q->transactions, t); | |
53 | set_free(t->queries); | |
54 | ||
55 | while ((i = set_steal_first(t->zone_items))) | |
56 | i->probe_transaction = NULL; | |
57 | set_free(t->zone_items); | |
58 | ||
59 | free(t); | |
60 | return NULL; | |
61 | } | |
62 | ||
63 | DEFINE_TRIVIAL_CLEANUP_FUNC(DnsTransaction*, dns_transaction_free); | |
64 | ||
65 | void dns_transaction_gc(DnsTransaction *t) { | |
66 | assert(t); | |
67 | ||
68 | if (t->block_gc > 0) | |
69 | return; | |
70 | ||
71 | if (set_isempty(t->queries) && set_isempty(t->zone_items)) | |
72 | dns_transaction_free(t); | |
73 | } | |
74 | ||
75 | int dns_transaction_new(DnsTransaction **ret, DnsScope *s, DnsQuestion *q) { | |
76 | _cleanup_(dns_transaction_freep) DnsTransaction *t = NULL; | |
77 | int r; | |
78 | ||
79 | assert(ret); | |
80 | assert(s); | |
81 | assert(q); | |
82 | ||
d5099efc | 83 | r = hashmap_ensure_allocated(&s->manager->dns_transactions, NULL); |
ec2c5e43 LP |
84 | if (r < 0) |
85 | return r; | |
86 | ||
87 | t = new0(DnsTransaction, 1); | |
88 | if (!t) | |
89 | return -ENOMEM; | |
90 | ||
91 | t->question = dns_question_ref(q); | |
92 | ||
93 | do | |
94 | random_bytes(&t->id, sizeof(t->id)); | |
95 | while (t->id == 0 || | |
96 | hashmap_get(s->manager->dns_transactions, UINT_TO_PTR(t->id))); | |
97 | ||
98 | r = hashmap_put(s->manager->dns_transactions, UINT_TO_PTR(t->id), t); | |
99 | if (r < 0) { | |
100 | t->id = 0; | |
101 | return r; | |
102 | } | |
103 | ||
104 | LIST_PREPEND(transactions_by_scope, s->transactions, t); | |
105 | t->scope = s; | |
106 | ||
107 | if (ret) | |
108 | *ret = t; | |
109 | ||
110 | t = NULL; | |
111 | ||
112 | return 0; | |
113 | } | |
114 | ||
115 | static void dns_transaction_stop(DnsTransaction *t) { | |
116 | assert(t); | |
117 | ||
118 | t->timeout_event_source = sd_event_source_unref(t->timeout_event_source); | |
119 | t->stream = dns_stream_free(t->stream); | |
120 | } | |
121 | ||
122 | static void dns_transaction_tentative(DnsTransaction *t, DnsPacket *p) { | |
2fb3034c | 123 | _cleanup_free_ char *pretty = NULL; |
ec2c5e43 | 124 | DnsZoneItem *z; |
ec2c5e43 LP |
125 | |
126 | assert(t); | |
127 | assert(p); | |
128 | ||
129 | if (manager_our_packet(t->scope->manager, p) != 0) | |
130 | return; | |
131 | ||
2fb3034c LP |
132 | in_addr_to_string(p->family, &p->sender, &pretty); |
133 | ||
134 | log_debug("Transaction on scope %s on %s/%s got tentative packet from %s", | |
ec2c5e43 LP |
135 | dns_protocol_to_string(t->scope->protocol), |
136 | t->scope->link ? t->scope->link->name : "*", | |
2fb3034c LP |
137 | t->scope->family == AF_UNSPEC ? "*" : af_to_name(t->scope->family), |
138 | pretty); | |
ec2c5e43 | 139 | |
a4076574 LP |
140 | /* RFC 4795, Section 4.1 says that the peer with the |
141 | * lexicographically smaller IP address loses */ | |
4d91eec4 LP |
142 | if (memcmp(&p->sender, &p->destination, FAMILY_ADDRESS_SIZE(p->family)) >= 0) { |
143 | log_debug("Peer has lexicographically larger IP address and thus lost in the conflict."); | |
a4076574 LP |
144 | return; |
145 | } | |
146 | ||
4d91eec4 | 147 | log_debug("We have the lexicographically larger IP address and thus lost in the conflict."); |
a4076574 | 148 | |
ec2c5e43 | 149 | t->block_gc++; |
3ef64445 LP |
150 | while ((z = set_first(t->zone_items))) { |
151 | /* First, make sure the zone item drops the reference | |
152 | * to us */ | |
153 | dns_zone_item_probe_stop(z); | |
154 | ||
155 | /* Secondly, report this as conflict, so that we might | |
156 | * look for a different hostname */ | |
ec2c5e43 | 157 | dns_zone_item_conflict(z); |
3ef64445 | 158 | } |
ec2c5e43 LP |
159 | t->block_gc--; |
160 | ||
161 | dns_transaction_gc(t); | |
162 | } | |
163 | ||
164 | void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state) { | |
165 | DnsQuery *q; | |
166 | DnsZoneItem *z; | |
167 | Iterator i; | |
168 | ||
169 | assert(t); | |
170 | assert(!IN_SET(state, DNS_TRANSACTION_NULL, DNS_TRANSACTION_PENDING)); | |
e56187ca LP |
171 | |
172 | if (!IN_SET(t->state, DNS_TRANSACTION_NULL, DNS_TRANSACTION_PENDING)) | |
173 | return; | |
ec2c5e43 LP |
174 | |
175 | /* Note that this call might invalidate the query. Callers | |
176 | * should hence not attempt to access the query or transaction | |
177 | * after calling this function. */ | |
178 | ||
179 | log_debug("Transaction on scope %s on %s/%s now complete with <%s>", | |
180 | dns_protocol_to_string(t->scope->protocol), | |
181 | t->scope->link ? t->scope->link->name : "*", | |
182 | t->scope->family == AF_UNSPEC ? "*" : af_to_name(t->scope->family), | |
183 | dns_transaction_state_to_string(state)); | |
184 | ||
185 | t->state = state; | |
186 | ||
187 | dns_transaction_stop(t); | |
188 | ||
189 | /* Notify all queries that are interested, but make sure the | |
190 | * transaction isn't freed while we are still looking at it */ | |
191 | t->block_gc++; | |
192 | SET_FOREACH(q, t->queries, i) | |
193 | dns_query_ready(q); | |
194 | SET_FOREACH(z, t->zone_items, i) | |
195 | dns_zone_item_ready(z); | |
196 | t->block_gc--; | |
197 | ||
198 | dns_transaction_gc(t); | |
199 | } | |
200 | ||
201 | static int on_stream_complete(DnsStream *s, int error) { | |
202 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; | |
203 | DnsTransaction *t; | |
204 | ||
205 | assert(s); | |
206 | assert(s->transaction); | |
207 | ||
208 | /* Copy the data we care about out of the stream before we | |
209 | * destroy it. */ | |
210 | t = s->transaction; | |
211 | p = dns_packet_ref(s->read_packet); | |
212 | ||
213 | t->stream = dns_stream_free(t->stream); | |
214 | ||
215 | if (error != 0) { | |
216 | dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES); | |
217 | return 0; | |
218 | } | |
219 | ||
a4076574 LP |
220 | if (dns_packet_validate_reply(p) <= 0) { |
221 | log_debug("Invalid LLMNR TCP packet."); | |
222 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
223 | return 0; | |
224 | } | |
225 | ||
226 | dns_scope_check_conflicts(t->scope, p); | |
227 | ||
ec2c5e43 LP |
228 | t->block_gc++; |
229 | dns_transaction_process_reply(t, p); | |
230 | t->block_gc--; | |
231 | ||
232 | /* If the response wasn't useful, then complete the transition now */ | |
233 | if (t->state == DNS_TRANSACTION_PENDING) | |
234 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
235 | ||
236 | return 0; | |
237 | } | |
238 | ||
239 | static int dns_transaction_open_tcp(DnsTransaction *t) { | |
240 | _cleanup_close_ int fd = -1; | |
241 | int r; | |
242 | ||
243 | assert(t); | |
244 | ||
245 | if (t->stream) | |
246 | return 0; | |
247 | ||
248 | if (t->scope->protocol == DNS_PROTOCOL_DNS) | |
249 | fd = dns_scope_tcp_socket(t->scope, AF_UNSPEC, NULL, 53); | |
250 | else if (t->scope->protocol == DNS_PROTOCOL_LLMNR) { | |
251 | ||
252 | /* When we already received a query to this (but it was truncated), send to its sender address */ | |
253 | if (t->received) | |
254 | fd = dns_scope_tcp_socket(t->scope, t->received->family, &t->received->sender, t->received->sender_port); | |
255 | else { | |
256 | union in_addr_union address; | |
a7f7d1bd | 257 | int family = AF_UNSPEC; |
ec2c5e43 LP |
258 | |
259 | /* Otherwise, try to talk to the owner of a | |
260 | * the IP address, in case this is a reverse | |
261 | * PTR lookup */ | |
262 | r = dns_question_extract_reverse_address(t->question, &family, &address); | |
263 | if (r < 0) | |
264 | return r; | |
265 | if (r == 0) | |
266 | return -EINVAL; | |
267 | ||
22a37591 | 268 | fd = dns_scope_tcp_socket(t->scope, family, &address, LLMNR_PORT); |
ec2c5e43 LP |
269 | } |
270 | } else | |
271 | return -EAFNOSUPPORT; | |
272 | ||
273 | if (fd < 0) | |
274 | return fd; | |
275 | ||
276 | r = dns_stream_new(t->scope->manager, &t->stream, t->scope->protocol, fd); | |
277 | if (r < 0) | |
278 | return r; | |
279 | ||
280 | fd = -1; | |
281 | ||
282 | r = dns_stream_write_packet(t->stream, t->sent); | |
283 | if (r < 0) { | |
284 | t->stream = dns_stream_free(t->stream); | |
285 | return r; | |
286 | } | |
287 | ||
288 | t->received = dns_packet_unref(t->received); | |
289 | t->stream->complete = on_stream_complete; | |
290 | t->stream->transaction = t; | |
291 | ||
292 | /* The interface index is difficult to determine if we are | |
293 | * connecting to the local host, hence fill this in right away | |
294 | * instead of determining it from the socket */ | |
295 | if (t->scope->link) | |
296 | t->stream->ifindex = t->scope->link->ifindex; | |
297 | ||
298 | return 0; | |
299 | } | |
300 | ||
301 | void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) { | |
302 | int r; | |
303 | ||
304 | assert(t); | |
305 | assert(p); | |
306 | assert(t->state == DNS_TRANSACTION_PENDING); | |
307 | ||
308 | /* Note that this call might invalidate the query. Callers | |
309 | * should hence not attempt to access the query or transaction | |
310 | * after calling this function. */ | |
311 | ||
312 | if (t->scope->protocol == DNS_PROTOCOL_LLMNR) { | |
313 | assert(t->scope->link); | |
314 | ||
315 | /* For LLMNR we will not accept any packets from other | |
316 | * interfaces */ | |
317 | ||
318 | if (p->ifindex != t->scope->link->ifindex) | |
319 | return; | |
320 | ||
321 | if (p->family != t->scope->family) | |
322 | return; | |
323 | ||
324 | /* Tentative packets are not full responses but still | |
325 | * useful for identifying uniqueness conflicts during | |
326 | * probing. */ | |
8b757a38 | 327 | if (DNS_PACKET_LLMNR_T(p)) { |
ec2c5e43 LP |
328 | dns_transaction_tentative(t, p); |
329 | return; | |
330 | } | |
331 | } | |
332 | ||
333 | if (t->scope->protocol == DNS_PROTOCOL_DNS) { | |
334 | ||
335 | /* For DNS we are fine with accepting packets on any | |
336 | * interface, but the source IP address must be one of | |
337 | * a valid DNS server */ | |
338 | ||
339 | if (!dns_scope_good_dns_server(t->scope, p->family, &p->sender)) | |
340 | return; | |
341 | ||
342 | if (p->sender_port != 53) | |
343 | return; | |
344 | } | |
345 | ||
346 | if (t->received != p) { | |
347 | dns_packet_unref(t->received); | |
348 | t->received = dns_packet_ref(p); | |
349 | } | |
350 | ||
351 | if (p->ipproto == IPPROTO_TCP) { | |
352 | if (DNS_PACKET_TC(p)) { | |
353 | /* Truncated via TCP? Somebody must be fucking with us */ | |
354 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
355 | return; | |
356 | } | |
357 | ||
358 | if (DNS_PACKET_ID(p) != t->id) { | |
359 | /* Not the reply to our query? Somebody must be fucking with us */ | |
360 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
361 | return; | |
362 | } | |
363 | } | |
364 | ||
365 | if (DNS_PACKET_TC(p)) { | |
366 | /* Response was truncated, let's try again with good old TCP */ | |
367 | r = dns_transaction_open_tcp(t); | |
368 | if (r == -ESRCH) { | |
369 | /* No servers found? Damn! */ | |
370 | dns_transaction_complete(t, DNS_TRANSACTION_NO_SERVERS); | |
371 | return; | |
372 | } | |
373 | if (r < 0) { | |
374 | /* On LLMNR, if we cannot connect to the host, | |
375 | * we immediately give up */ | |
376 | if (t->scope->protocol == DNS_PROTOCOL_LLMNR) { | |
377 | dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES); | |
378 | return; | |
379 | } | |
380 | ||
381 | /* On DNS, couldn't send? Try immediately again, with a new server */ | |
382 | dns_scope_next_dns_server(t->scope); | |
383 | ||
384 | r = dns_transaction_go(t); | |
385 | if (r < 0) { | |
386 | dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES); | |
387 | return; | |
388 | } | |
389 | ||
390 | return; | |
391 | } | |
392 | } | |
393 | ||
394 | /* Parse and update the cache */ | |
395 | r = dns_packet_extract(p); | |
396 | if (r < 0) { | |
397 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
398 | return; | |
399 | } | |
400 | ||
401 | /* According to RFC 4795, section 2.9. only the RRs from the answer section shall be cached */ | |
a4076574 | 402 | dns_cache_put(&t->scope->cache, p->question, DNS_PACKET_RCODE(p), p->answer, DNS_PACKET_ANCOUNT(p), 0, p->family, &p->sender); |
ec2c5e43 LP |
403 | |
404 | if (DNS_PACKET_RCODE(p) == DNS_RCODE_SUCCESS) | |
405 | dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS); | |
406 | else | |
407 | dns_transaction_complete(t, DNS_TRANSACTION_FAILURE); | |
408 | } | |
409 | ||
410 | static int on_transaction_timeout(sd_event_source *s, usec_t usec, void *userdata) { | |
411 | DnsTransaction *t = userdata; | |
412 | int r; | |
413 | ||
414 | assert(s); | |
415 | assert(t); | |
416 | ||
417 | /* Timeout reached? Try again, with a new server */ | |
418 | dns_scope_next_dns_server(t->scope); | |
419 | ||
420 | r = dns_transaction_go(t); | |
421 | if (r < 0) | |
422 | dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES); | |
423 | ||
424 | return 0; | |
425 | } | |
426 | ||
427 | static int dns_transaction_make_packet(DnsTransaction *t) { | |
428 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; | |
429 | unsigned n, added = 0; | |
430 | int r; | |
431 | ||
432 | assert(t); | |
433 | ||
434 | if (t->sent) | |
435 | return 0; | |
436 | ||
437 | r = dns_packet_new_query(&p, t->scope->protocol, 0); | |
438 | if (r < 0) | |
439 | return r; | |
440 | ||
441 | for (n = 0; n < t->question->n_keys; n++) { | |
442 | r = dns_scope_good_key(t->scope, t->question->keys[n]); | |
443 | if (r < 0) | |
444 | return r; | |
445 | if (r == 0) | |
446 | continue; | |
447 | ||
448 | r = dns_packet_append_key(p, t->question->keys[n], NULL); | |
449 | if (r < 0) | |
450 | return r; | |
451 | ||
452 | added++; | |
453 | } | |
454 | ||
455 | if (added <= 0) | |
456 | return -EDOM; | |
457 | ||
458 | DNS_PACKET_HEADER(p)->qdcount = htobe16(added); | |
459 | DNS_PACKET_HEADER(p)->id = t->id; | |
460 | ||
461 | t->sent = p; | |
462 | p = NULL; | |
463 | ||
464 | return 0; | |
465 | } | |
466 | ||
467 | int dns_transaction_go(DnsTransaction *t) { | |
468 | bool had_stream; | |
469 | int r; | |
470 | ||
471 | assert(t); | |
472 | ||
473 | had_stream = !!t->stream; | |
474 | ||
475 | dns_transaction_stop(t); | |
476 | ||
e56187ca | 477 | log_debug("Excercising transaction on scope %s on %s/%s", |
ec2c5e43 LP |
478 | dns_protocol_to_string(t->scope->protocol), |
479 | t->scope->link ? t->scope->link->name : "*", | |
480 | t->scope->family == AF_UNSPEC ? "*" : af_to_name(t->scope->family)); | |
481 | ||
482 | if (t->n_attempts >= TRANSACTION_ATTEMPTS_MAX(t->scope->protocol)) { | |
483 | dns_transaction_complete(t, DNS_TRANSACTION_ATTEMPTS_MAX_REACHED); | |
484 | return 0; | |
485 | } | |
486 | ||
487 | if (t->scope->protocol == DNS_PROTOCOL_LLMNR && had_stream) { | |
488 | /* If we already tried via a stream, then we don't | |
489 | * retry on LLMNR. See RFC 4795, Section 2.7. */ | |
490 | dns_transaction_complete(t, DNS_TRANSACTION_ATTEMPTS_MAX_REACHED); | |
491 | return 0; | |
492 | } | |
493 | ||
494 | t->n_attempts++; | |
495 | t->received = dns_packet_unref(t->received); | |
496 | t->cached = dns_answer_unref(t->cached); | |
497 | t->cached_rcode = 0; | |
498 | ||
4d926a69 LP |
499 | /* Check the cache, but only if this transaction is not used |
500 | * for probing or verifying a zone item. */ | |
501 | if (set_isempty(t->zone_items)) { | |
2c27fbca | 502 | |
4d926a69 LP |
503 | /* Before trying the cache, let's make sure we figured out a |
504 | * server to use. Should this cause a change of server this | |
505 | * might flush the cache. */ | |
506 | dns_scope_get_dns_server(t->scope); | |
2c27fbca | 507 | |
4d926a69 LP |
508 | /* Let's then prune all outdated entries */ |
509 | dns_cache_prune(&t->scope->cache); | |
510 | ||
511 | r = dns_cache_lookup(&t->scope->cache, t->question, &t->cached_rcode, &t->cached); | |
512 | if (r < 0) | |
513 | return r; | |
514 | if (r > 0) { | |
515 | log_debug("Cache hit!"); | |
516 | if (t->cached_rcode == DNS_RCODE_SUCCESS) | |
517 | dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS); | |
518 | else | |
519 | dns_transaction_complete(t, DNS_TRANSACTION_FAILURE); | |
520 | return 0; | |
521 | } | |
ec2c5e43 LP |
522 | } |
523 | ||
6e068472 LP |
524 | if (t->scope->protocol == DNS_PROTOCOL_LLMNR && !t->initial_jitter) { |
525 | usec_t jitter; | |
526 | ||
527 | /* RFC 4795 Section 2.7 suggests all queries should be | |
528 | * delayed by a random time from 0 to JITTER_INTERVAL. */ | |
529 | ||
530 | t->initial_jitter = true; | |
531 | ||
532 | random_bytes(&jitter, sizeof(jitter)); | |
533 | jitter %= LLMNR_JITTER_INTERVAL_USEC; | |
534 | ||
535 | r = sd_event_add_time( | |
536 | t->scope->manager->event, | |
537 | &t->timeout_event_source, | |
538 | clock_boottime_or_monotonic(), | |
a4076574 LP |
539 | now(clock_boottime_or_monotonic()) + jitter, |
540 | LLMNR_JITTER_INTERVAL_USEC, | |
6e068472 LP |
541 | on_transaction_timeout, t); |
542 | if (r < 0) | |
543 | return r; | |
544 | ||
545 | t->n_attempts = 0; | |
546 | t->state = DNS_TRANSACTION_PENDING; | |
547 | ||
548 | log_debug("Delaying LLMNR transaction for " USEC_FMT "us.", jitter); | |
549 | return 0; | |
550 | } | |
551 | ||
2c27fbca LP |
552 | log_debug("Cache miss!"); |
553 | ||
ec2c5e43 LP |
554 | /* Otherwise, we need to ask the network */ |
555 | r = dns_transaction_make_packet(t); | |
556 | if (r == -EDOM) { | |
557 | /* Not the right request to make on this network? | |
558 | * (i.e. an A request made on IPv6 or an AAAA request | |
559 | * made on IPv4, on LLMNR or mDNS.) */ | |
560 | dns_transaction_complete(t, DNS_TRANSACTION_NO_SERVERS); | |
561 | return 0; | |
562 | } | |
563 | if (r < 0) | |
564 | return r; | |
565 | ||
566 | if (t->scope->protocol == DNS_PROTOCOL_LLMNR && | |
567 | (dns_question_endswith(t->question, "in-addr.arpa") > 0 || | |
568 | dns_question_endswith(t->question, "ip6.arpa") > 0)) { | |
569 | ||
570 | /* RFC 4795, Section 2.4. says reverse lookups shall | |
571 | * always be made via TCP on LLMNR */ | |
572 | r = dns_transaction_open_tcp(t); | |
573 | } else { | |
574 | /* Try via UDP, and if that fails due to large size try via TCP */ | |
a4076574 | 575 | r = dns_scope_emit(t->scope, t->sent); |
ec2c5e43 LP |
576 | if (r == -EMSGSIZE) |
577 | r = dns_transaction_open_tcp(t); | |
578 | } | |
579 | if (r == -ESRCH) { | |
580 | /* No servers to send this to? */ | |
581 | dns_transaction_complete(t, DNS_TRANSACTION_NO_SERVERS); | |
582 | return 0; | |
583 | } | |
584 | if (r < 0) { | |
13b551ac LP |
585 | if (t->scope->protocol != DNS_PROTOCOL_DNS) { |
586 | dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES); | |
587 | return 0; | |
588 | } | |
589 | ||
ec2c5e43 LP |
590 | /* Couldn't send? Try immediately again, with a new server */ |
591 | dns_scope_next_dns_server(t->scope); | |
592 | ||
593 | return dns_transaction_go(t); | |
594 | } | |
595 | ||
9a015429 LP |
596 | r = sd_event_add_time( |
597 | t->scope->manager->event, | |
598 | &t->timeout_event_source, | |
599 | clock_boottime_or_monotonic(), | |
600 | now(clock_boottime_or_monotonic()) + TRANSACTION_TIMEOUT_USEC(t->scope->protocol), 0, | |
601 | on_transaction_timeout, t); | |
ec2c5e43 LP |
602 | if (r < 0) |
603 | return r; | |
604 | ||
605 | t->state = DNS_TRANSACTION_PENDING; | |
606 | return 1; | |
607 | } | |
608 | ||
609 | static const char* const dns_transaction_state_table[_DNS_TRANSACTION_STATE_MAX] = { | |
610 | [DNS_TRANSACTION_NULL] = "null", | |
611 | [DNS_TRANSACTION_PENDING] = "pending", | |
612 | [DNS_TRANSACTION_FAILURE] = "failure", | |
613 | [DNS_TRANSACTION_SUCCESS] = "success", | |
614 | [DNS_TRANSACTION_NO_SERVERS] = "no-servers", | |
615 | [DNS_TRANSACTION_TIMEOUT] = "timeout", | |
616 | [DNS_TRANSACTION_ATTEMPTS_MAX_REACHED] = "attempts-max-reached", | |
617 | [DNS_TRANSACTION_INVALID_REPLY] = "invalid-reply", | |
618 | [DNS_TRANSACTION_RESOURCES] = "resources", | |
619 | [DNS_TRANSACTION_ABORTED] = "aborted", | |
620 | }; | |
621 | DEFINE_STRING_TABLE_LOOKUP(dns_transaction_state, DnsTransactionState); |