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1 /***
2   This file is part of avahi.
3
4   avahi is free software; you can redistribute it and/or modify it
5   under the terms of the GNU Lesser General Public License as
6   published by the Free Software Foundation; either version 2.1 of the
7   License, or (at your option) any later version.
8
9   avahi is distributed in the hope that it will be useful, but WITHOUT
10   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
11   or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
12   Public License for more details.
13
14   You should have received a copy of the GNU Lesser General Public
15   License along with avahi; if not, write to the Free Software
16   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
17   USA.
18 ***/
19
20 #ifdef HAVE_CONFIG_H
21 #include <config.h>
22 #endif
23
24 #include <sys/types.h>
25 #include <sys/socket.h>
26 #include <netinet/in.h>
27 #include <arpa/inet.h>
28 #include <string.h>
29 #include <sys/utsname.h>
30 #include <unistd.h>
31 #include <errno.h>
32 #include <stdio.h>
33 #include <assert.h>
34 #include <stdlib.h>
35
36 #include <avahi-common/domain.h>
37 #include <avahi-common/timeval.h>
38 #include <avahi-common/malloc.h>
39 #include <avahi-common/error.h>
40
41 #include "internal.h"
42 #include "iface.h"
43 #include "socket.h"
44 #include "browse.h"
45 #include "log.h"
46 #include "util.h"
47 #include "dns-srv-rr.h"
48 #include "addr-util.h"
49 #include "domain-util.h"
50 #include "rr-util.h"
51
52 #define AVAHI_DEFAULT_CACHE_ENTRIES_MAX 4096
53
54 static void enum_aux_records(AvahiServer *s, AvahiInterface *i, const char *name, uint16_t type, void (*callback)(AvahiServer *s, AvahiRecord *r, int flush_cache, void* userdata), void* userdata) {
55     assert(s);
56     assert(i);
57     assert(name);
58     assert(callback);
59
60     if (type == AVAHI_DNS_TYPE_ANY) {
61         AvahiEntry *e;
62
63         for (e = s->entries; e; e = e->entries_next)
64             if (!e->dead &&
65                 avahi_entry_is_registered(s, e, i) &&
66                 e->record->key->clazz == AVAHI_DNS_CLASS_IN &&
67                 avahi_domain_equal(name, e->record->key->name))
68                 callback(s, e->record, e->flags & AVAHI_PUBLISH_UNIQUE, userdata);
69
70     } else {
71         AvahiEntry *e;
72         AvahiKey *k;
73
74         if (!(k = avahi_key_new(name, AVAHI_DNS_CLASS_IN, type)))
75             return; /** OOM */
76
77         for (e = avahi_hashmap_lookup(s->entries_by_key, k); e; e = e->by_key_next)
78             if (!e->dead && avahi_entry_is_registered(s, e, i))
79                 callback(s, e->record, e->flags & AVAHI_PUBLISH_UNIQUE, userdata);
80
81         avahi_key_unref(k);
82     }
83 }
84
85 void avahi_server_enumerate_aux_records(AvahiServer *s, AvahiInterface *i, AvahiRecord *r, void (*callback)(AvahiServer *s, AvahiRecord *r, int flush_cache, void* userdata), void* userdata) {
86     assert(s);
87     assert(i);
88     assert(r);
89     assert(callback);
90
91     /* Call the specified callback far all records referenced by the one specified in *r */
92
93     if (r->key->clazz == AVAHI_DNS_CLASS_IN) {
94         if (r->key->type == AVAHI_DNS_TYPE_PTR) {
95             enum_aux_records(s, i, r->data.ptr.name, AVAHI_DNS_TYPE_SRV, callback, userdata);
96             enum_aux_records(s, i, r->data.ptr.name, AVAHI_DNS_TYPE_TXT, callback, userdata);
97         } else if (r->key->type == AVAHI_DNS_TYPE_SRV) {
98             enum_aux_records(s, i, r->data.srv.name, AVAHI_DNS_TYPE_A, callback, userdata);
99             enum_aux_records(s, i, r->data.srv.name, AVAHI_DNS_TYPE_AAAA, callback, userdata);
100         } else if (r->key->type == AVAHI_DNS_TYPE_CNAME)
101             enum_aux_records(s, i, r->data.cname.name, AVAHI_DNS_TYPE_ANY, callback, userdata);
102     }
103 }
104
105 void avahi_server_prepare_response(AvahiServer *s, AvahiInterface *i, AvahiEntry *e, int unicast_response, int auxiliary) {
106     assert(s);
107     assert(i);
108     assert(e);
109
110     avahi_record_list_push(s->record_list, e->record, e->flags & AVAHI_PUBLISH_UNIQUE, unicast_response, auxiliary);
111 }
112
113 void avahi_server_prepare_matching_responses(AvahiServer *s, AvahiInterface *i, AvahiKey *k, int unicast_response) {
114     assert(s);
115     assert(i);
116     assert(k);
117
118     /* Push all records that match the specified key to the record list */
119
120     if (avahi_key_is_pattern(k)) {
121         AvahiEntry *e;
122
123         /* Handle ANY query */
124
125         for (e = s->entries; e; e = e->entries_next)
126             if (!e->dead && avahi_key_pattern_match(k, e->record->key) && avahi_entry_is_registered(s, e, i))
127                 avahi_server_prepare_response(s, i, e, unicast_response, 0);
128
129     } else {
130         AvahiEntry *e;
131
132         /* Handle all other queries */
133
134         for (e = avahi_hashmap_lookup(s->entries_by_key, k); e; e = e->by_key_next)
135             if (!e->dead && avahi_entry_is_registered(s, e, i))
136                 avahi_server_prepare_response(s, i, e, unicast_response, 0);
137     }
138
139     /* Look for CNAME records */
140
141     if ((k->clazz == AVAHI_DNS_CLASS_IN || k->clazz == AVAHI_DNS_CLASS_ANY)
142         && k->type != AVAHI_DNS_TYPE_CNAME && k->type != AVAHI_DNS_TYPE_ANY) {
143
144         AvahiKey *cname_key;
145
146         if (!(cname_key = avahi_key_new(k->name, AVAHI_DNS_CLASS_IN, AVAHI_DNS_TYPE_CNAME)))
147             return;
148
149         avahi_server_prepare_matching_responses(s, i, cname_key, unicast_response);
150         avahi_key_unref(cname_key);
151     }
152 }
153
154 static void withdraw_entry(AvahiServer *s, AvahiEntry *e) {
155     assert(s);
156     assert(e);
157
158     /* Withdraw the specified entry, and if is part of an entry group,
159      * put that into COLLISION state */
160
161     if (e->dead)
162         return;
163
164     if (e->group) {
165         AvahiEntry *k;
166
167         for (k = e->group->entries; k; k = k->by_group_next)
168             if (!k->dead) {
169                 avahi_goodbye_entry(s, k, 0, 1);
170                 k->dead = 1;
171             }
172
173         e->group->n_probing = 0;
174
175         avahi_s_entry_group_change_state(e->group, AVAHI_ENTRY_GROUP_COLLISION);
176     } else {
177         avahi_goodbye_entry(s, e, 0, 1);
178         e->dead = 1;
179     }
180
181     s->need_entry_cleanup = 1;
182 }
183
184 static void withdraw_rrset(AvahiServer *s, AvahiKey *key) {
185     AvahiEntry *e;
186
187     assert(s);
188     assert(key);
189
190     /* Withdraw an entry RRSset */
191
192     for (e = avahi_hashmap_lookup(s->entries_by_key, key); e; e = e->by_key_next)
193         withdraw_entry(s, e);
194 }
195
196 static void incoming_probe(AvahiServer *s, AvahiRecord *record, AvahiInterface *i) {
197     AvahiEntry *e, *n;
198     int ours = 0, won = 0, lost = 0;
199
200     assert(s);
201     assert(record);
202     assert(i);
203
204     /* Handle incoming probes and check if they conflict our own probes */
205
206     for (e = avahi_hashmap_lookup(s->entries_by_key, record->key); e; e = n) {
207         int cmp;
208         n = e->by_key_next;
209
210         if (e->dead)
211             continue;
212
213         if ((cmp = avahi_record_lexicographical_compare(e->record, record)) == 0) {
214             ours = 1;
215             break;
216         } else {
217
218             if (avahi_entry_is_probing(s, e, i)) {
219                 if (cmp > 0)
220                     won = 1;
221                 else /* cmp < 0 */
222                     lost = 1;
223             }
224         }
225     }
226
227     if (!ours) {
228         char *t = avahi_record_to_string(record);
229
230         if (won)
231             avahi_log_debug("Received conflicting probe [%s]. Local host won.", t);
232         else if (lost) {
233             avahi_log_debug("Received conflicting probe [%s]. Local host lost. Withdrawing.", t);
234             withdraw_rrset(s, record->key);
235         }
236
237         avahi_free(t);
238     }
239 }
240
241 static int handle_conflict(AvahiServer *s, AvahiInterface *i, AvahiRecord *record, int unique) {
242     int valid = 1, ours = 0, conflict = 0, withdraw_immediately = 0;
243     AvahiEntry *e, *n, *conflicting_entry = NULL;
244
245     assert(s);
246     assert(i);
247     assert(record);
248
249     /* Check whether an incoming record conflicts with one of our own */
250
251     for (e = avahi_hashmap_lookup(s->entries_by_key, record->key); e; e = n) {
252         n = e->by_key_next;
253
254         if (e->dead)
255             continue;
256
257         /* Check if the incoming is a goodbye record */
258         if (avahi_record_is_goodbye(record)) {
259
260             if (avahi_record_equal_no_ttl(e->record, record)) {
261                 char *t;
262
263                 /* Refresh */
264                 t = avahi_record_to_string(record);
265                 avahi_log_debug("Received goodbye record for one of our records [%s]. Refreshing.", t);
266                 avahi_server_prepare_matching_responses(s, i, e->record->key, 0);
267
268                 valid = 0;
269                 avahi_free(t);
270                 break;
271             }
272
273             /* If the goodybe packet doesn't match one of our own RRs, we simply ignore it. */
274             continue;
275         }
276
277         if (!(e->flags & AVAHI_PUBLISH_UNIQUE) && !unique)
278             continue;
279
280         /* Either our entry or the other is intended to be unique, so let's check */
281
282         if (avahi_record_equal_no_ttl(e->record, record)) {
283             ours = 1; /* We have an identical record, so this is no conflict */
284
285             /* Check wheter there is a TTL conflict */
286             if (record->ttl <= e->record->ttl/2 &&
287                 avahi_entry_is_registered(s, e, i)) {
288                 char *t;
289                 /* Refresh */
290                 t = avahi_record_to_string(record);
291
292                 avahi_log_debug("Received record with bad TTL [%s]. Refreshing.", t);
293                 avahi_server_prepare_matching_responses(s, i, e->record->key, 0);
294                 valid = 0;
295
296                 avahi_free(t);
297             }
298
299             /* There's no need to check the other entries of this RRset */
300             break;
301
302         } else {
303
304             if (avahi_entry_is_registered(s, e, i)) {
305
306                 /* A conflict => we have to return to probe mode */
307                 conflict = 1;
308                 conflicting_entry = e;
309
310             } else if (avahi_entry_is_probing(s, e, i)) {
311
312                 /* We are currently registering a matching record, but
313                  * someone else already claimed it, so let's
314                  * withdraw */
315                 conflict = 1;
316                 withdraw_immediately = 1;
317             }
318         }
319     }
320
321     if (!ours && conflict) {
322         char *t;
323
324         valid = 0;
325
326         t = avahi_record_to_string(record);
327
328         if (withdraw_immediately) {
329             avahi_log_debug("Received conflicting record [%s] with local record to be. Withdrawing.", t);
330             withdraw_rrset(s, record->key);
331         } else {
332             assert(conflicting_entry);
333             avahi_log_debug("Received conflicting record [%s]. Resetting our record.", t);
334             avahi_entry_return_to_initial_state(s, conflicting_entry, i);
335
336             /* Local unique records are returned to probing
337              * state. Local shared records are reannounced. */
338         }
339
340         avahi_free(t);
341     }
342
343     return valid;
344 }
345
346 static void append_aux_callback(AvahiServer *s, AvahiRecord *r, int flush_cache, void* userdata) {
347     int *unicast_response = userdata;
348
349     assert(s);
350     assert(r);
351     assert(unicast_response);
352
353     avahi_record_list_push(s->record_list, r, flush_cache, *unicast_response, 1);
354 }
355
356 static void append_aux_records_to_list(AvahiServer *s, AvahiInterface *i, AvahiRecord *r, int unicast_response) {
357     assert(s);
358     assert(r);
359
360     avahi_server_enumerate_aux_records(s, i, r, append_aux_callback, &unicast_response);
361 }
362
363 void avahi_server_generate_response(AvahiServer *s, AvahiInterface *i, AvahiDnsPacket *p, const AvahiAddress *a, uint16_t port, int legacy_unicast, int immediately) {
364
365     assert(s);
366     assert(i);
367     assert(!legacy_unicast || (a && port > 0 && p));
368
369     if (legacy_unicast) {
370         AvahiDnsPacket *reply;
371         AvahiRecord *r;
372
373         if (!(reply = avahi_dns_packet_new_reply(p, 512 + AVAHI_DNS_PACKET_EXTRA_SIZE /* unicast DNS maximum packet size is 512 */ , 1, 1)))
374             return; /* OOM */
375
376         while ((r = avahi_record_list_next(s->record_list, NULL, NULL, NULL))) {
377
378             append_aux_records_to_list(s, i, r, 0);
379
380             if (avahi_dns_packet_append_record(reply, r, 0, 10))
381                 avahi_dns_packet_inc_field(reply, AVAHI_DNS_FIELD_ANCOUNT);
382             else {
383                 char *t = avahi_record_to_string(r);
384                 avahi_log_warn("Record [%s] not fitting in legacy unicast packet, dropping.", t);
385                 avahi_free(t);
386             }
387
388             avahi_record_unref(r);
389         }
390
391         if (avahi_dns_packet_get_field(reply, AVAHI_DNS_FIELD_ANCOUNT) != 0)
392             avahi_interface_send_packet_unicast(i, reply, a, port);
393
394         avahi_dns_packet_free(reply);
395
396     } else {
397         int unicast_response, flush_cache, auxiliary;
398         AvahiDnsPacket *reply = NULL;
399         AvahiRecord *r;
400
401         /* In case the query packet was truncated never respond
402         immediately, because known answer suppression records might be
403         contained in later packets */
404         int tc = p && !!(avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS) & AVAHI_DNS_FLAG_TC);
405
406         while ((r = avahi_record_list_next(s->record_list, &flush_cache, &unicast_response, &auxiliary))) {
407
408             int im = immediately;
409
410             /* Only send the response immediately if it contains a
411              * unique entry AND it is not in reply to a truncated
412              * packet AND it is not an auxiliary record AND all other
413              * responses for this record are unique too. */
414
415             if (flush_cache && !tc && !auxiliary && avahi_record_list_all_flush_cache(s->record_list))
416                 im = 1;
417
418             if (!avahi_interface_post_response(i, r, flush_cache, a, im) && unicast_response) {
419
420                 /* Due to some reasons the record has not been scheduled.
421                  * The client requested an unicast response in that
422                  * case. Therefore we prepare such a response */
423
424                 append_aux_records_to_list(s, i, r, unicast_response);
425
426                 for (;;) {
427
428                     if (!reply) {
429                         assert(p);
430
431                         if (!(reply = avahi_dns_packet_new_reply(p, i->hardware->mtu, 0, 0)))
432                             break; /* OOM */
433                     }
434
435                     if (avahi_dns_packet_append_record(reply, r, flush_cache, 0)) {
436
437                         /* Appending this record succeeded, so incremeant
438                          * the specific header field, and return to the caller */
439
440                         avahi_dns_packet_inc_field(reply, AVAHI_DNS_FIELD_ANCOUNT);
441                         break;
442                     }
443
444                     if (avahi_dns_packet_get_field(reply, AVAHI_DNS_FIELD_ANCOUNT) == 0) {
445                         size_t size;
446
447                         /* The record is too large for one packet, so create a larger packet */
448
449                         avahi_dns_packet_free(reply);
450                         size = avahi_record_get_estimate_size(r) + AVAHI_DNS_PACKET_HEADER_SIZE;
451
452                         if (!(reply = avahi_dns_packet_new_reply(p, size + AVAHI_DNS_PACKET_EXTRA_SIZE, 0, 1)))
453                             break; /* OOM */
454
455                         if (avahi_dns_packet_append_record(reply, r, flush_cache, 0)) {
456
457                             /* Appending this record succeeded, so incremeant
458                              * the specific header field, and return to the caller */
459
460                             avahi_dns_packet_inc_field(reply, AVAHI_DNS_FIELD_ANCOUNT);
461                             break;
462
463                         }  else {
464
465                             /* We completely fucked up, there's
466                              * nothing we can do. The RR just doesn't
467                              * fit in. Let's ignore it. */
468
469                             char *t;
470                             avahi_dns_packet_free(reply);
471                             reply = NULL;
472                             t = avahi_record_to_string(r);
473                             avahi_log_warn("Record [%s] too large, doesn't fit in any packet!", t);
474                             avahi_free(t);
475                             break;
476                         }
477                     }
478
479                     /* Appending the record didn't succeeed, so let's send this packet, and create a new one */
480                     avahi_interface_send_packet_unicast(i, reply, a, port);
481                     avahi_dns_packet_free(reply);
482                     reply = NULL;
483                 }
484             }
485
486             avahi_record_unref(r);
487         }
488
489         if (reply) {
490             if (avahi_dns_packet_get_field(reply, AVAHI_DNS_FIELD_ANCOUNT) != 0)
491                 avahi_interface_send_packet_unicast(i, reply, a, port);
492             avahi_dns_packet_free(reply);
493         }
494     }
495
496     avahi_record_list_flush(s->record_list);
497 }
498
499 static void reflect_response(AvahiServer *s, AvahiInterface *i, AvahiRecord *r, int flush_cache) {
500     AvahiInterface *j;
501
502     assert(s);
503     assert(i);
504     assert(r);
505
506     if (!s->config.enable_reflector)
507         return;
508
509     for (j = s->monitor->interfaces; j; j = j->interface_next)
510         if (j != i && (s->config.reflect_ipv || j->protocol == i->protocol))
511             avahi_interface_post_response(j, r, flush_cache, NULL, 1);
512 }
513
514 static void* reflect_cache_walk_callback(AvahiCache *c, AvahiKey *pattern, AvahiCacheEntry *e, void* userdata) {
515     AvahiServer *s = userdata;
516
517     assert(c);
518     assert(pattern);
519     assert(e);
520     assert(s);
521
522     avahi_record_list_push(s->record_list, e->record, e->cache_flush, 0, 0);
523     return NULL;
524 }
525
526 static void reflect_query(AvahiServer *s, AvahiInterface *i, AvahiKey *k) {
527     AvahiInterface *j;
528
529     assert(s);
530     assert(i);
531     assert(k);
532
533     if (!s->config.enable_reflector)
534         return;
535
536     for (j = s->monitor->interfaces; j; j = j->interface_next)
537         if (j != i && (s->config.reflect_ipv || j->protocol == i->protocol)) {
538             /* Post the query to other networks */
539             avahi_interface_post_query(j, k, 1, NULL);
540
541             /* Reply from caches of other network. This is needed to
542              * "work around" known answer suppression. */
543
544             avahi_cache_walk(j->cache, k, reflect_cache_walk_callback, s);
545         }
546 }
547
548 static void reflect_probe(AvahiServer *s, AvahiInterface *i, AvahiRecord *r) {
549     AvahiInterface *j;
550
551     assert(s);
552     assert(i);
553     assert(r);
554
555     if (!s->config.enable_reflector)
556         return;
557
558     for (j = s->monitor->interfaces; j; j = j->interface_next)
559         if (j != i && (s->config.reflect_ipv || j->protocol == i->protocol))
560             avahi_interface_post_probe(j, r, 1);
561 }
562
563 static void handle_query_packet(AvahiServer *s, AvahiDnsPacket *p, AvahiInterface *i, const AvahiAddress *a, uint16_t port, int legacy_unicast, int from_local_iface) {
564     size_t n;
565     int is_probe;
566
567     assert(s);
568     assert(p);
569     assert(i);
570     assert(a);
571
572     assert(avahi_record_list_is_empty(s->record_list));
573
574     is_probe = avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_NSCOUNT) > 0;
575
576     /* Handle the questions */
577     for (n = avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_QDCOUNT); n > 0; n --) {
578         AvahiKey *key;
579         int unicast_response = 0;
580
581         if (!(key = avahi_dns_packet_consume_key(p, &unicast_response))) {
582             avahi_log_warn(__FILE__": Packet too short or invalid while reading question key. (Maybe a UTF-8 problem?)");
583             goto fail;
584         }
585
586         if (!legacy_unicast && !from_local_iface) {
587             reflect_query(s, i, key);
588             if (!unicast_response)
589               avahi_cache_start_poof(i->cache, key, a);
590         }
591
592         if (avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_ANCOUNT) == 0 &&
593             !(avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS) & AVAHI_DNS_FLAG_TC))
594             /* Allow our own queries to be suppressed by incoming
595              * queries only when they do not include known answers */
596             avahi_query_scheduler_incoming(i->query_scheduler, key);
597
598         avahi_server_prepare_matching_responses(s, i, key, unicast_response);
599         avahi_key_unref(key);
600     }
601
602     if (!legacy_unicast) {
603
604         /* Known Answer Suppression */
605         for (n = avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_ANCOUNT); n > 0; n --) {
606             AvahiRecord *record;
607             int unique = 0;
608
609             if (!(record = avahi_dns_packet_consume_record(p, &unique))) {
610                 avahi_log_warn(__FILE__": Packet too short or invalid while reading known answer record. (Maybe a UTF-8 problem?)");
611                 goto fail;
612             }
613
614             avahi_response_scheduler_suppress(i->response_scheduler, record, a);
615             avahi_record_list_drop(s->record_list, record);
616             avahi_cache_stop_poof(i->cache, record, a);
617
618             avahi_record_unref(record);
619         }
620
621         /* Probe record */
622         for (n = avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_NSCOUNT); n > 0; n --) {
623             AvahiRecord *record;
624             int unique = 0;
625
626             if (!(record = avahi_dns_packet_consume_record(p, &unique))) {
627                 avahi_log_warn(__FILE__": Packet too short or invalid while reading probe record. (Maybe a UTF-8 problem?)");
628                 goto fail;
629             }
630
631             if (!avahi_key_is_pattern(record->key)) {
632                 if (!from_local_iface)
633                     reflect_probe(s, i, record);
634                 incoming_probe(s, record, i);
635             }
636
637             avahi_record_unref(record);
638         }
639     }
640
641     if (!avahi_record_list_is_empty(s->record_list))
642         avahi_server_generate_response(s, i, p, a, port, legacy_unicast, is_probe);
643
644     return;
645
646 fail:
647     avahi_record_list_flush(s->record_list);
648 }
649
650 static void handle_response_packet(AvahiServer *s, AvahiDnsPacket *p, AvahiInterface *i, const AvahiAddress *a, int from_local_iface) {
651     unsigned n;
652
653     assert(s);
654     assert(p);
655     assert(i);
656     assert(a);
657
658     for (n = avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_ANCOUNT) +
659              avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_ARCOUNT); n > 0; n--) {
660         AvahiRecord *record;
661         int cache_flush = 0;
662
663         if (!(record = avahi_dns_packet_consume_record(p, &cache_flush))) {
664             avahi_log_warn(__FILE__": Packet too short or invalid while reading response record. (Maybe a UTF-8 problem?)");
665             break;
666         }
667
668         if (!avahi_key_is_pattern(record->key)) {
669
670             if (handle_conflict(s, i, record, cache_flush)) {
671                 if (!from_local_iface && !avahi_record_is_link_local_address(record))
672                     reflect_response(s, i, record, cache_flush);
673                 avahi_cache_update(i->cache, record, cache_flush, a);
674                 avahi_response_scheduler_incoming(i->response_scheduler, record, cache_flush);
675             }
676         }
677
678         avahi_record_unref(record);
679     }
680
681     /* If the incoming response contained a conflicting record, some
682        records have been scheduled for sending. We need to flush them
683        here. */
684     if (!avahi_record_list_is_empty(s->record_list))
685         avahi_server_generate_response(s, i, NULL, NULL, 0, 0, 1);
686 }
687
688 static AvahiLegacyUnicastReflectSlot* allocate_slot(AvahiServer *s) {
689     unsigned n, idx = (unsigned) -1;
690     AvahiLegacyUnicastReflectSlot *slot;
691
692     assert(s);
693
694     if (!s->legacy_unicast_reflect_slots)
695         s->legacy_unicast_reflect_slots = avahi_new0(AvahiLegacyUnicastReflectSlot*, AVAHI_LEGACY_UNICAST_REFLECT_SLOTS_MAX);
696
697     for (n = 0; n < AVAHI_LEGACY_UNICAST_REFLECT_SLOTS_MAX; n++, s->legacy_unicast_reflect_id++) {
698         idx = s->legacy_unicast_reflect_id % AVAHI_LEGACY_UNICAST_REFLECT_SLOTS_MAX;
699
700         if (!s->legacy_unicast_reflect_slots[idx])
701             break;
702     }
703
704     if (idx == (unsigned) -1 || s->legacy_unicast_reflect_slots[idx])
705         return NULL;
706
707     if (!(slot = avahi_new(AvahiLegacyUnicastReflectSlot, 1)))
708         return NULL; /* OOM */
709
710     s->legacy_unicast_reflect_slots[idx] = slot;
711     slot->id = s->legacy_unicast_reflect_id++;
712     slot->server = s;
713
714     return slot;
715 }
716
717 static void deallocate_slot(AvahiServer *s, AvahiLegacyUnicastReflectSlot *slot) {
718     unsigned idx;
719
720     assert(s);
721     assert(slot);
722
723     idx = slot->id % AVAHI_LEGACY_UNICAST_REFLECT_SLOTS_MAX;
724
725     assert(s->legacy_unicast_reflect_slots[idx] == slot);
726
727     avahi_time_event_free(slot->time_event);
728
729     avahi_free(slot);
730     s->legacy_unicast_reflect_slots[idx] = NULL;
731 }
732
733 static void free_slots(AvahiServer *s) {
734     unsigned idx;
735     assert(s);
736
737     if (!s->legacy_unicast_reflect_slots)
738         return;
739
740     for (idx = 0; idx < AVAHI_LEGACY_UNICAST_REFLECT_SLOTS_MAX; idx ++)
741         if (s->legacy_unicast_reflect_slots[idx])
742             deallocate_slot(s, s->legacy_unicast_reflect_slots[idx]);
743
744     avahi_free(s->legacy_unicast_reflect_slots);
745     s->legacy_unicast_reflect_slots = NULL;
746 }
747
748 static AvahiLegacyUnicastReflectSlot* find_slot(AvahiServer *s, uint16_t id) {
749     unsigned idx;
750
751     assert(s);
752
753     if (!s->legacy_unicast_reflect_slots)
754         return NULL;
755
756     idx = id % AVAHI_LEGACY_UNICAST_REFLECT_SLOTS_MAX;
757
758     if (!s->legacy_unicast_reflect_slots[idx] || s->legacy_unicast_reflect_slots[idx]->id != id)
759         return NULL;
760
761     return s->legacy_unicast_reflect_slots[idx];
762 }
763
764 static void legacy_unicast_reflect_slot_timeout(AvahiTimeEvent *e, void *userdata) {
765     AvahiLegacyUnicastReflectSlot *slot = userdata;
766
767     assert(e);
768     assert(slot);
769     assert(slot->time_event == e);
770
771     deallocate_slot(slot->server, slot);
772 }
773
774 static void reflect_legacy_unicast_query_packet(AvahiServer *s, AvahiDnsPacket *p, AvahiInterface *i, const AvahiAddress *a, uint16_t port) {
775     AvahiLegacyUnicastReflectSlot *slot;
776     AvahiInterface *j;
777
778     assert(s);
779     assert(p);
780     assert(i);
781     assert(a);
782     assert(port > 0);
783     assert(i->protocol == a->proto);
784
785     if (!s->config.enable_reflector)
786         return;
787
788     /* Reflecting legacy unicast queries is a little more complicated
789        than reflecting normal queries, since we must route the
790        responses back to the right client. Therefore we must store
791        some information for finding the right client contact data for
792        response packets. In contrast to normal queries legacy
793        unicast query and response packets are reflected untouched and
794        are not reassembled into larger packets */
795
796     if (!(slot = allocate_slot(s))) {
797         /* No slot available, we drop this legacy unicast query */
798         avahi_log_warn("No slot available for legacy unicast reflection, dropping query packet.");
799         return;
800     }
801
802     slot->original_id = avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_ID);
803     slot->address = *a;
804     slot->port = port;
805     slot->interface = i->hardware->index;
806
807     avahi_elapse_time(&slot->elapse_time, 2000, 0);
808     slot->time_event = avahi_time_event_new(s->time_event_queue, &slot->elapse_time, legacy_unicast_reflect_slot_timeout, slot);
809
810     /* Patch the packet with our new locally generatet id */
811     avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_ID, slot->id);
812
813     for (j = s->monitor->interfaces; j; j = j->interface_next)
814         if (j->announcing &&
815             j != i &&
816             (s->config.reflect_ipv || j->protocol == i->protocol)) {
817
818             if (j->protocol == AVAHI_PROTO_INET && s->fd_legacy_unicast_ipv4 >= 0) {
819                 avahi_send_dns_packet_ipv4(s->fd_legacy_unicast_ipv4, j->hardware->index, p, NULL, NULL, 0);
820             } else if (j->protocol == AVAHI_PROTO_INET6 && s->fd_legacy_unicast_ipv6 >= 0)
821                 avahi_send_dns_packet_ipv6(s->fd_legacy_unicast_ipv6, j->hardware->index, p, NULL, NULL, 0);
822         }
823
824     /* Reset the id */
825     avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_ID, slot->original_id);
826 }
827
828 static int originates_from_local_legacy_unicast_socket(AvahiServer *s, const AvahiAddress *address, uint16_t port) {
829     assert(s);
830     assert(address);
831     assert(port > 0);
832
833     if (!s->config.enable_reflector)
834         return 0;
835
836     if (!avahi_address_is_local(s->monitor, address))
837         return 0;
838
839     if (address->proto == AVAHI_PROTO_INET && s->fd_legacy_unicast_ipv4 >= 0) {
840         struct sockaddr_in lsa;
841         socklen_t l = sizeof(lsa);
842
843         if (getsockname(s->fd_legacy_unicast_ipv4, (struct sockaddr*) &lsa, &l) != 0)
844             avahi_log_warn("getsockname(): %s", strerror(errno));
845         else
846             return avahi_port_from_sockaddr((struct sockaddr*) &lsa) == port;
847
848     }
849
850     if (address->proto == AVAHI_PROTO_INET6 && s->fd_legacy_unicast_ipv6 >= 0) {
851         struct sockaddr_in6 lsa;
852         socklen_t l = sizeof(lsa);
853
854         if (getsockname(s->fd_legacy_unicast_ipv6, (struct sockaddr*) &lsa, &l) != 0)
855             avahi_log_warn("getsockname(): %s", strerror(errno));
856         else
857             return avahi_port_from_sockaddr((struct sockaddr*) &lsa) == port;
858     }
859
860     return 0;
861 }
862
863 static int is_mdns_mcast_address(const AvahiAddress *a) {
864     AvahiAddress b;
865     assert(a);
866
867     avahi_address_parse(a->proto == AVAHI_PROTO_INET ? AVAHI_IPV4_MCAST_GROUP : AVAHI_IPV6_MCAST_GROUP, a->proto, &b);
868     return avahi_address_cmp(a, &b) == 0;
869 }
870
871 static int originates_from_local_iface(AvahiServer *s, AvahiIfIndex iface, const AvahiAddress *a, uint16_t port) {
872     assert(s);
873     assert(iface != AVAHI_IF_UNSPEC);
874     assert(a);
875
876     /* If it isn't the MDNS port it can't be generated by us */
877     if (port != AVAHI_MDNS_PORT)
878         return 0;
879
880     return avahi_interface_has_address(s->monitor, iface, a);
881 }
882
883 static void dispatch_packet(AvahiServer *s, AvahiDnsPacket *p, const AvahiAddress *src_address, uint16_t port, const AvahiAddress *dst_address, AvahiIfIndex iface, int ttl) {
884     AvahiInterface *i;
885     int from_local_iface = 0;
886
887     assert(s);
888     assert(p);
889     assert(src_address);
890     assert(dst_address);
891     assert(iface > 0);
892     assert(src_address->proto == dst_address->proto);
893
894     if (!(i = avahi_interface_monitor_get_interface(s->monitor, iface, src_address->proto)) ||
895         !i->announcing) {
896         avahi_log_warn("Received packet from invalid interface.");
897         return;
898     }
899
900     if (port <= 0) {
901         /* This fixes RHBZ #475394 */
902         avahi_log_warn("Received packet from invalid source port %u.", (unsigned) port);
903         return;
904     }
905
906     if (avahi_address_is_ipv4_in_ipv6(src_address))
907         /* This is an IPv4 address encapsulated in IPv6, so let's ignore it. */
908         return;
909
910     if (originates_from_local_legacy_unicast_socket(s, src_address, port))
911         /* This originates from our local reflector, so let's ignore it */
912         return;
913
914     /* We don't want to reflect local traffic, so we check if this packet is generated locally. */
915     if (s->config.enable_reflector)
916         from_local_iface = originates_from_local_iface(s, iface, src_address, port);
917
918     if (avahi_dns_packet_check_valid_multicast(p) < 0) {
919         avahi_log_warn("Received invalid packet.");
920         return;
921     }
922
923     if (avahi_dns_packet_is_query(p)) {
924         int legacy_unicast = 0;
925
926         /* For queries EDNS0 might allow ARCOUNT != 0. We ignore the
927          * AR section completely here, so far. Until the day we add
928          * EDNS0 support. */
929
930         if (port != AVAHI_MDNS_PORT) {
931             /* Legacy Unicast */
932
933             if ((avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_ANCOUNT) != 0 ||
934                  avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_NSCOUNT) != 0)) {
935                 avahi_log_warn("Invalid legacy unicast query packet.");
936                 return;
937             }
938
939             legacy_unicast = 1;
940         }
941
942         if (legacy_unicast)
943             reflect_legacy_unicast_query_packet(s, p, i, src_address, port);
944
945         handle_query_packet(s, p, i, src_address, port, legacy_unicast, from_local_iface);
946
947     } else {
948         char t[AVAHI_ADDRESS_STR_MAX];
949
950         if (port != AVAHI_MDNS_PORT) {
951             avahi_log_warn("Received response from host %s with invalid source port %u on interface '%s.%i'", avahi_address_snprint(t, sizeof(t), src_address), port, i->hardware->name, i->protocol);
952             return;
953         }
954
955         if (ttl != 255 && s->config.check_response_ttl) {
956             avahi_log_warn("Received response from host %s with invalid TTL %u on interface '%s.%i'.", avahi_address_snprint(t, sizeof(t), src_address), ttl, i->hardware->name, i->protocol);
957             return;
958         }
959
960         if (!is_mdns_mcast_address(dst_address) &&
961             !avahi_interface_address_on_link(i, src_address)) {
962
963             avahi_log_warn("Received non-local response from host %s on interface '%s.%i'.", avahi_address_snprint(t, sizeof(t), src_address), i->hardware->name, i->protocol);
964             return;
965         }
966
967         if (avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_QDCOUNT) != 0 ||
968             avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_ANCOUNT) == 0 ||
969             avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_NSCOUNT) != 0) {
970
971             avahi_log_warn("Invalid response packet from host %s.", avahi_address_snprint(t, sizeof(t), src_address));
972             return;
973         }
974
975         handle_response_packet(s, p, i, src_address, from_local_iface);
976     }
977 }
978
979 static void dispatch_legacy_unicast_packet(AvahiServer *s, AvahiDnsPacket *p) {
980     AvahiInterface *j;
981     AvahiLegacyUnicastReflectSlot *slot;
982
983     assert(s);
984     assert(p);
985
986     if (avahi_dns_packet_check_valid(p) < 0 || avahi_dns_packet_is_query(p)) {
987         avahi_log_warn("Received invalid packet.");
988         return;
989     }
990
991     if (!(slot = find_slot(s, avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_ID)))) {
992         avahi_log_warn("Received legacy unicast response with unknown id");
993         return;
994     }
995
996     if (!(j = avahi_interface_monitor_get_interface(s->monitor, slot->interface, slot->address.proto)) ||
997         !j->announcing)
998         return;
999
1000     /* Patch the original ID into this response */
1001     avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_ID, slot->original_id);
1002
1003     /* Forward the response to the correct client */
1004     avahi_interface_send_packet_unicast(j, p, &slot->address, slot->port);
1005
1006     /* Undo changes to packet */
1007     avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_ID, slot->id);
1008 }
1009
1010 static void mcast_socket_event(AvahiWatch *w, int fd, AvahiWatchEvent events, void *userdata) {
1011     AvahiServer *s = userdata;
1012     AvahiAddress dest, src;
1013     AvahiDnsPacket *p = NULL;
1014     AvahiIfIndex iface;
1015     uint16_t port;
1016     uint8_t ttl;
1017
1018     assert(w);
1019     assert(fd >= 0);
1020     assert(events & AVAHI_WATCH_IN);
1021
1022     if (fd == s->fd_ipv4) {
1023         dest.proto = src.proto = AVAHI_PROTO_INET;
1024         p = avahi_recv_dns_packet_ipv4(s->fd_ipv4, &src.data.ipv4, &port, &dest.data.ipv4, &iface, &ttl);
1025     } else {
1026         assert(fd == s->fd_ipv6);
1027         dest.proto = src.proto = AVAHI_PROTO_INET6;
1028         p = avahi_recv_dns_packet_ipv6(s->fd_ipv6, &src.data.ipv6, &port, &dest.data.ipv6, &iface, &ttl);
1029     }
1030
1031     if (p) {
1032         if (iface == AVAHI_IF_UNSPEC)
1033             iface = avahi_find_interface_for_address(s->monitor, &dest);
1034
1035         if (iface != AVAHI_IF_UNSPEC)
1036             dispatch_packet(s, p, &src, port, &dest, iface, ttl);
1037         else
1038             avahi_log_error("Incoming packet received on address that isn't local.");
1039
1040         avahi_dns_packet_free(p);
1041
1042         avahi_cleanup_dead_entries(s);
1043     }
1044 }
1045
1046 static void legacy_unicast_socket_event(AvahiWatch *w, int fd, AvahiWatchEvent events, void *userdata) {
1047     AvahiServer *s = userdata;
1048     AvahiDnsPacket *p = NULL;
1049
1050     assert(w);
1051     assert(fd >= 0);
1052     assert(events & AVAHI_WATCH_IN);
1053
1054     if (fd == s->fd_legacy_unicast_ipv4)
1055         p = avahi_recv_dns_packet_ipv4(s->fd_legacy_unicast_ipv4, NULL, NULL, NULL, NULL, NULL);
1056     else {
1057         assert(fd == s->fd_legacy_unicast_ipv6);
1058         p = avahi_recv_dns_packet_ipv6(s->fd_legacy_unicast_ipv6, NULL, NULL, NULL, NULL, NULL);
1059     }
1060
1061     if (p) {
1062         dispatch_legacy_unicast_packet(s, p);
1063         avahi_dns_packet_free(p);
1064
1065         avahi_cleanup_dead_entries(s);
1066     }
1067 }
1068
1069 static void server_set_state(AvahiServer *s, AvahiServerState state) {
1070     assert(s);
1071
1072     if (s->state == state)
1073         return;
1074
1075     s->state = state;
1076
1077     avahi_interface_monitor_update_rrs(s->monitor, 0);
1078
1079     if (s->callback)
1080         s->callback(s, state, s->userdata);
1081 }
1082
1083 static void withdraw_host_rrs(AvahiServer *s) {
1084     assert(s);
1085
1086     if (s->hinfo_entry_group)
1087         avahi_s_entry_group_reset(s->hinfo_entry_group);
1088
1089     if (s->browse_domain_entry_group)
1090         avahi_s_entry_group_reset(s->browse_domain_entry_group);
1091
1092     avahi_interface_monitor_update_rrs(s->monitor, 1);
1093     s->n_host_rr_pending = 0;
1094 }
1095
1096 void avahi_server_decrease_host_rr_pending(AvahiServer *s) {
1097     assert(s);
1098
1099     assert(s->n_host_rr_pending > 0);
1100
1101     if (--s->n_host_rr_pending == 0)
1102         server_set_state(s, AVAHI_SERVER_RUNNING);
1103 }
1104
1105 void avahi_host_rr_entry_group_callback(AvahiServer *s, AvahiSEntryGroup *g, AvahiEntryGroupState state, AVAHI_GCC_UNUSED void *userdata) {
1106     assert(s);
1107     assert(g);
1108
1109     if (state == AVAHI_ENTRY_GROUP_REGISTERING &&
1110         s->state == AVAHI_SERVER_REGISTERING)
1111         s->n_host_rr_pending ++;
1112
1113     else if (state == AVAHI_ENTRY_GROUP_COLLISION &&
1114         (s->state == AVAHI_SERVER_REGISTERING || s->state == AVAHI_SERVER_RUNNING)) {
1115         withdraw_host_rrs(s);
1116         server_set_state(s, AVAHI_SERVER_COLLISION);
1117
1118     } else if (state == AVAHI_ENTRY_GROUP_ESTABLISHED &&
1119                s->state == AVAHI_SERVER_REGISTERING)
1120         avahi_server_decrease_host_rr_pending(s);
1121 }
1122
1123 static void register_hinfo(AvahiServer *s) {
1124     struct utsname utsname;
1125     AvahiRecord *r;
1126
1127     assert(s);
1128
1129     if (!s->config.publish_hinfo)
1130         return;
1131
1132     if (s->hinfo_entry_group)
1133         assert(avahi_s_entry_group_is_empty(s->hinfo_entry_group));
1134     else
1135         s->hinfo_entry_group = avahi_s_entry_group_new(s, avahi_host_rr_entry_group_callback, NULL);
1136
1137     if (!s->hinfo_entry_group) {
1138         avahi_log_warn("Failed to create HINFO entry group: %s", avahi_strerror(s->error));
1139         return;
1140     }
1141
1142     /* Fill in HINFO rr */
1143     if ((r = avahi_record_new_full(s->host_name_fqdn, AVAHI_DNS_CLASS_IN, AVAHI_DNS_TYPE_HINFO, AVAHI_DEFAULT_TTL_HOST_NAME))) {
1144
1145         if (uname(&utsname) < 0)
1146             avahi_log_warn("uname() failed: %s\n", avahi_strerror(errno));
1147         else {
1148
1149             r->data.hinfo.cpu = avahi_strdup(avahi_strup(utsname.machine));
1150             r->data.hinfo.os = avahi_strdup(avahi_strup(utsname.sysname));
1151
1152             avahi_log_info("Registering HINFO record with values '%s'/'%s'.", r->data.hinfo.cpu, r->data.hinfo.os);
1153
1154             if (avahi_server_add(s, s->hinfo_entry_group, AVAHI_IF_UNSPEC, AVAHI_PROTO_UNSPEC, AVAHI_PUBLISH_UNIQUE, r) < 0) {
1155                 avahi_log_warn("Failed to add HINFO RR: %s", avahi_strerror(s->error));
1156                 return;
1157             }
1158         }
1159
1160         avahi_record_unref(r);
1161     }
1162
1163     if (avahi_s_entry_group_commit(s->hinfo_entry_group) < 0)
1164         avahi_log_warn("Failed to commit HINFO entry group: %s", avahi_strerror(s->error));
1165
1166 }
1167
1168 static void register_localhost(AvahiServer *s) {
1169     AvahiAddress a;
1170     assert(s);
1171
1172     /* Add localhost entries */
1173     avahi_address_parse("127.0.0.1", AVAHI_PROTO_INET, &a);
1174     avahi_server_add_address(s, NULL, AVAHI_IF_UNSPEC, AVAHI_PROTO_UNSPEC, AVAHI_PUBLISH_NO_PROBE|AVAHI_PUBLISH_NO_ANNOUNCE, "localhost", &a);
1175
1176     avahi_address_parse("::1", AVAHI_PROTO_INET6, &a);
1177     avahi_server_add_address(s, NULL, AVAHI_IF_UNSPEC, AVAHI_PROTO_UNSPEC, AVAHI_PUBLISH_NO_PROBE|AVAHI_PUBLISH_NO_ANNOUNCE, "ip6-localhost", &a);
1178 }
1179
1180 static void register_browse_domain(AvahiServer *s) {
1181     assert(s);
1182
1183     if (!s->config.publish_domain)
1184         return;
1185
1186     if (avahi_domain_equal(s->domain_name, "local"))
1187         return;
1188
1189     if (s->browse_domain_entry_group)
1190         assert(avahi_s_entry_group_is_empty(s->browse_domain_entry_group));
1191     else
1192         s->browse_domain_entry_group = avahi_s_entry_group_new(s, NULL, NULL);
1193
1194     if (!s->browse_domain_entry_group) {
1195         avahi_log_warn("Failed to create browse domain entry group: %s", avahi_strerror(s->error));
1196         return;
1197     }
1198
1199     if (avahi_server_add_ptr(s, s->browse_domain_entry_group, AVAHI_IF_UNSPEC, AVAHI_PROTO_UNSPEC, 0, AVAHI_DEFAULT_TTL, "b._dns-sd._udp.local", s->domain_name) < 0) {
1200         avahi_log_warn("Failed to add browse domain RR: %s", avahi_strerror(s->error));
1201         return;
1202     }
1203
1204     if (avahi_s_entry_group_commit(s->browse_domain_entry_group) < 0)
1205         avahi_log_warn("Failed to commit browse domain entry group: %s", avahi_strerror(s->error));
1206 }
1207
1208 static void register_stuff(AvahiServer *s) {
1209     assert(s);
1210
1211     server_set_state(s, AVAHI_SERVER_REGISTERING);
1212     s->n_host_rr_pending ++; /** Make sure that the state isn't changed tp AVAHI_SERVER_RUNNING too early */
1213
1214     register_hinfo(s);
1215     register_browse_domain(s);
1216     avahi_interface_monitor_update_rrs(s->monitor, 0);
1217
1218     s->n_host_rr_pending --;
1219
1220     if (s->n_host_rr_pending == 0)
1221         server_set_state(s, AVAHI_SERVER_RUNNING);
1222 }
1223
1224 static void update_fqdn(AvahiServer *s) {
1225     char *n;
1226
1227     assert(s);
1228     assert(s->host_name);
1229     assert(s->domain_name);
1230
1231     if (!(n = avahi_strdup_printf("%s.%s", s->host_name, s->domain_name)))
1232         return; /* OOM */
1233
1234     avahi_free(s->host_name_fqdn);
1235     s->host_name_fqdn = n;
1236 }
1237
1238 int avahi_server_set_host_name(AvahiServer *s, const char *host_name) {
1239     char *hn = NULL;
1240     assert(s);
1241
1242     AVAHI_CHECK_VALIDITY(s, !host_name || avahi_is_valid_host_name(host_name), AVAHI_ERR_INVALID_HOST_NAME);
1243
1244     if (!host_name)
1245         hn = avahi_get_host_name_strdup();
1246     else
1247         hn = avahi_normalize_name_strdup(host_name);
1248
1249     hn[strcspn(hn, ".")] = 0;
1250
1251     if (avahi_domain_equal(s->host_name, hn) && s->state != AVAHI_SERVER_COLLISION) {
1252         avahi_free(hn);
1253         return avahi_server_set_errno(s, AVAHI_ERR_NO_CHANGE);
1254     }
1255
1256     withdraw_host_rrs(s);
1257
1258     avahi_free(s->host_name);
1259     s->host_name = hn;
1260
1261     update_fqdn(s);
1262
1263     register_stuff(s);
1264     return AVAHI_OK;
1265 }
1266
1267 int avahi_server_set_domain_name(AvahiServer *s, const char *domain_name) {
1268     char *dn = NULL;
1269     assert(s);
1270
1271     AVAHI_CHECK_VALIDITY(s, !domain_name || avahi_is_valid_domain_name(domain_name), AVAHI_ERR_INVALID_DOMAIN_NAME);
1272
1273     if (!domain_name)
1274         dn = avahi_strdup("local");
1275     else
1276         dn = avahi_normalize_name_strdup(domain_name);
1277
1278     if (avahi_domain_equal(s->domain_name, domain_name)) {
1279         avahi_free(dn);
1280         return avahi_server_set_errno(s, AVAHI_ERR_NO_CHANGE);
1281     }
1282
1283     withdraw_host_rrs(s);
1284
1285     avahi_free(s->domain_name);
1286     s->domain_name = dn;
1287     update_fqdn(s);
1288
1289     register_stuff(s);
1290
1291     avahi_free(dn);
1292     return AVAHI_OK;
1293 }
1294
1295 static int valid_server_config(const AvahiServerConfig *sc) {
1296     AvahiStringList *l;
1297
1298     assert(sc);
1299
1300     if (sc->n_wide_area_servers > AVAHI_WIDE_AREA_SERVERS_MAX)
1301         return AVAHI_ERR_INVALID_CONFIG;
1302
1303     if (sc->host_name && !avahi_is_valid_host_name(sc->host_name))
1304         return AVAHI_ERR_INVALID_HOST_NAME;
1305
1306     if (sc->domain_name && !avahi_is_valid_domain_name(sc->domain_name))
1307         return AVAHI_ERR_INVALID_DOMAIN_NAME;
1308
1309     for (l = sc->browse_domains; l; l = l->next)
1310         if (!avahi_is_valid_domain_name((char*) l->text))
1311             return AVAHI_ERR_INVALID_DOMAIN_NAME;
1312
1313     return AVAHI_OK;
1314 }
1315
1316 static int setup_sockets(AvahiServer *s) {
1317     assert(s);
1318
1319     s->fd_ipv4 = s->config.use_ipv4 ? avahi_open_socket_ipv4(s->config.disallow_other_stacks) : -1;
1320     s->fd_ipv6 = s->config.use_ipv6 ? avahi_open_socket_ipv6(s->config.disallow_other_stacks) : -1;
1321
1322     if (s->fd_ipv6 < 0 && s->fd_ipv4 < 0)
1323         return AVAHI_ERR_NO_NETWORK;
1324
1325     if (s->fd_ipv4 < 0 && s->config.use_ipv4)
1326         avahi_log_notice("Failed to create IPv4 socket, proceeding in IPv6 only mode");
1327     else if (s->fd_ipv6 < 0 && s->config.use_ipv6)
1328         avahi_log_notice("Failed to create IPv6 socket, proceeding in IPv4 only mode");
1329
1330     s->fd_legacy_unicast_ipv4 = s->fd_ipv4 >= 0 && s->config.enable_reflector ? avahi_open_unicast_socket_ipv4() : -1;
1331     s->fd_legacy_unicast_ipv6 = s->fd_ipv6 >= 0 && s->config.enable_reflector ? avahi_open_unicast_socket_ipv6() : -1;
1332
1333     s->watch_ipv4 =
1334         s->watch_ipv6 =
1335         s->watch_legacy_unicast_ipv4 =
1336         s->watch_legacy_unicast_ipv6 = NULL;
1337
1338     if (s->fd_ipv4 >= 0)
1339         s->watch_ipv4 = s->poll_api->watch_new(s->poll_api, s->fd_ipv4, AVAHI_WATCH_IN, mcast_socket_event, s);
1340     if (s->fd_ipv6 >= 0)
1341         s->watch_ipv6 = s->poll_api->watch_new(s->poll_api, s->fd_ipv6, AVAHI_WATCH_IN, mcast_socket_event, s);
1342
1343     if (s->fd_legacy_unicast_ipv4 >= 0)
1344         s->watch_legacy_unicast_ipv4 = s->poll_api->watch_new(s->poll_api, s->fd_legacy_unicast_ipv4, AVAHI_WATCH_IN, legacy_unicast_socket_event, s);
1345     if (s->fd_legacy_unicast_ipv6 >= 0)
1346         s->watch_legacy_unicast_ipv6 = s->poll_api->watch_new(s->poll_api, s->fd_legacy_unicast_ipv6, AVAHI_WATCH_IN, legacy_unicast_socket_event, s);
1347
1348     return 0;
1349 }
1350
1351 AvahiServer *avahi_server_new(const AvahiPoll *poll_api, const AvahiServerConfig *sc, AvahiServerCallback callback, void* userdata, int *error) {
1352     AvahiServer *s;
1353     int e;
1354
1355     if (sc && (e = valid_server_config(sc)) < 0) {
1356         if (error)
1357             *error = e;
1358         return NULL;
1359     }
1360
1361     if (!(s = avahi_new(AvahiServer, 1))) {
1362         if (error)
1363             *error = AVAHI_ERR_NO_MEMORY;
1364
1365         return NULL;
1366     }
1367
1368     s->poll_api = poll_api;
1369
1370     if (sc)
1371         avahi_server_config_copy(&s->config, sc);
1372     else
1373         avahi_server_config_init(&s->config);
1374
1375     if ((e = setup_sockets(s)) < 0) {
1376         if (error)
1377             *error = e;
1378
1379         avahi_server_config_free(&s->config);
1380         avahi_free(s);
1381
1382         return NULL;
1383     }
1384
1385     s->n_host_rr_pending = 0;
1386     s->need_entry_cleanup = 0;
1387     s->need_group_cleanup = 0;
1388     s->need_browser_cleanup = 0;
1389     s->hinfo_entry_group = NULL;
1390     s->browse_domain_entry_group = NULL;
1391     s->error = AVAHI_OK;
1392     s->state = AVAHI_SERVER_INVALID;
1393
1394     s->callback = callback;
1395     s->userdata = userdata;
1396
1397     s->time_event_queue = avahi_time_event_queue_new(poll_api);
1398
1399     s->entries_by_key = avahi_hashmap_new((AvahiHashFunc) avahi_key_hash, (AvahiEqualFunc) avahi_key_equal, NULL, NULL);
1400     AVAHI_LLIST_HEAD_INIT(AvahiEntry, s->entries);
1401     AVAHI_LLIST_HEAD_INIT(AvahiGroup, s->groups);
1402
1403     s->record_browser_hashmap = avahi_hashmap_new((AvahiHashFunc) avahi_key_hash, (AvahiEqualFunc) avahi_key_equal, NULL, NULL);
1404     AVAHI_LLIST_HEAD_INIT(AvahiSRecordBrowser, s->record_browsers);
1405     AVAHI_LLIST_HEAD_INIT(AvahiSHostNameResolver, s->host_name_resolvers);
1406     AVAHI_LLIST_HEAD_INIT(AvahiSAddressResolver, s->address_resolvers);
1407     AVAHI_LLIST_HEAD_INIT(AvahiSDomainBrowser, s->domain_browsers);
1408     AVAHI_LLIST_HEAD_INIT(AvahiSServiceTypeBrowser, s->service_type_browsers);
1409     AVAHI_LLIST_HEAD_INIT(AvahiSServiceBrowser, s->service_browsers);
1410     AVAHI_LLIST_HEAD_INIT(AvahiSServiceResolver, s->service_resolvers);
1411     AVAHI_LLIST_HEAD_INIT(AvahiSDNSServerBrowser, s->dns_server_browsers);
1412
1413     s->legacy_unicast_reflect_slots = NULL;
1414     s->legacy_unicast_reflect_id = 0;
1415
1416     s->record_list = avahi_record_list_new();
1417
1418     /* Get host name */
1419     s->host_name = s->config.host_name ? avahi_normalize_name_strdup(s->config.host_name) : avahi_get_host_name_strdup();
1420     s->host_name[strcspn(s->host_name, ".")] = 0;
1421     s->domain_name = s->config.domain_name ? avahi_normalize_name_strdup(s->config.domain_name) : avahi_strdup("local");
1422     s->host_name_fqdn = NULL;
1423     update_fqdn(s);
1424
1425     do {
1426         s->local_service_cookie = (uint32_t) rand() * (uint32_t) rand();
1427     } while (s->local_service_cookie == AVAHI_SERVICE_COOKIE_INVALID);
1428
1429     if (s->config.enable_wide_area) {
1430         s->wide_area_lookup_engine = avahi_wide_area_engine_new(s);
1431         avahi_wide_area_set_servers(s->wide_area_lookup_engine, s->config.wide_area_servers, s->config.n_wide_area_servers);
1432     } else
1433         s->wide_area_lookup_engine = NULL;
1434
1435     s->multicast_lookup_engine = avahi_multicast_lookup_engine_new(s);
1436
1437     s->monitor = avahi_interface_monitor_new(s);
1438     avahi_interface_monitor_sync(s->monitor);
1439
1440     register_localhost(s);
1441     register_stuff(s);
1442
1443     return s;
1444 }
1445
1446 void avahi_server_free(AvahiServer* s) {
1447     assert(s);
1448
1449     /* Remove all browsers */
1450
1451     while (s->dns_server_browsers)
1452         avahi_s_dns_server_browser_free(s->dns_server_browsers);
1453     while (s->host_name_resolvers)
1454         avahi_s_host_name_resolver_free(s->host_name_resolvers);
1455     while (s->address_resolvers)
1456         avahi_s_address_resolver_free(s->address_resolvers);
1457     while (s->domain_browsers)
1458         avahi_s_domain_browser_free(s->domain_browsers);
1459     while (s->service_type_browsers)
1460         avahi_s_service_type_browser_free(s->service_type_browsers);
1461     while (s->service_browsers)
1462         avahi_s_service_browser_free(s->service_browsers);
1463     while (s->service_resolvers)
1464         avahi_s_service_resolver_free(s->service_resolvers);
1465     while (s->record_browsers)
1466         avahi_s_record_browser_destroy(s->record_browsers);
1467
1468     /* Remove all locally rgeistered stuff */
1469
1470     while(s->entries)
1471         avahi_entry_free(s, s->entries);
1472
1473     avahi_interface_monitor_free(s->monitor);
1474
1475     while (s->groups)
1476         avahi_entry_group_free(s, s->groups);
1477
1478     free_slots(s);
1479
1480     avahi_hashmap_free(s->entries_by_key);
1481     avahi_record_list_free(s->record_list);
1482     avahi_hashmap_free(s->record_browser_hashmap);
1483
1484     if (s->wide_area_lookup_engine)
1485         avahi_wide_area_engine_free(s->wide_area_lookup_engine);
1486     avahi_multicast_lookup_engine_free(s->multicast_lookup_engine);
1487
1488     avahi_time_event_queue_free(s->time_event_queue);
1489
1490     /* Free watches */
1491
1492     if (s->watch_ipv4)
1493         s->poll_api->watch_free(s->watch_ipv4);
1494     if (s->watch_ipv6)
1495         s->poll_api->watch_free(s->watch_ipv6);
1496
1497     if (s->watch_legacy_unicast_ipv4)
1498         s->poll_api->watch_free(s->watch_legacy_unicast_ipv4);
1499     if (s->watch_legacy_unicast_ipv6)
1500         s->poll_api->watch_free(s->watch_legacy_unicast_ipv6);
1501
1502     /* Free sockets */
1503
1504     if (s->fd_ipv4 >= 0)
1505         close(s->fd_ipv4);
1506     if (s->fd_ipv6 >= 0)
1507         close(s->fd_ipv6);
1508
1509     if (s->fd_legacy_unicast_ipv4 >= 0)
1510         close(s->fd_legacy_unicast_ipv4);
1511     if (s->fd_legacy_unicast_ipv6 >= 0)
1512         close(s->fd_legacy_unicast_ipv6);
1513
1514     /* Free other stuff */
1515
1516     avahi_free(s->host_name);
1517     avahi_free(s->domain_name);
1518     avahi_free(s->host_name_fqdn);
1519
1520     avahi_server_config_free(&s->config);
1521
1522     avahi_free(s);
1523 }
1524
1525 const char* avahi_server_get_domain_name(AvahiServer *s) {
1526     assert(s);
1527
1528     return s->domain_name;
1529 }
1530
1531 const char* avahi_server_get_host_name(AvahiServer *s) {
1532     assert(s);
1533
1534     return s->host_name;
1535 }
1536
1537 const char* avahi_server_get_host_name_fqdn(AvahiServer *s) {
1538     assert(s);
1539
1540     return s->host_name_fqdn;
1541 }
1542
1543 void* avahi_server_get_data(AvahiServer *s) {
1544     assert(s);
1545
1546     return s->userdata;
1547 }
1548
1549 void avahi_server_set_data(AvahiServer *s, void* userdata) {
1550     assert(s);
1551
1552     s->userdata = userdata;
1553 }
1554
1555 AvahiServerState avahi_server_get_state(AvahiServer *s) {
1556     assert(s);
1557
1558     return s->state;
1559 }
1560
1561 AvahiServerConfig* avahi_server_config_init(AvahiServerConfig *c) {
1562     assert(c);
1563
1564     memset(c, 0, sizeof(AvahiServerConfig));
1565     c->use_ipv6 = 1;
1566     c->use_ipv4 = 1;
1567     c->allow_interfaces = NULL;
1568     c->deny_interfaces = NULL;
1569     c->host_name = NULL;
1570     c->domain_name = NULL;
1571     c->check_response_ttl = 0;
1572     c->publish_hinfo = 1;
1573     c->publish_addresses = 1;
1574     c->publish_workstation = 1;
1575     c->publish_domain = 1;
1576     c->use_iff_running = 0;
1577     c->enable_reflector = 0;
1578     c->reflect_ipv = 0;
1579     c->add_service_cookie = 0;
1580     c->enable_wide_area = 0;
1581     c->n_wide_area_servers = 0;
1582     c->disallow_other_stacks = 0;
1583     c->browse_domains = NULL;
1584     c->disable_publishing = 0;
1585     c->allow_point_to_point = 0;
1586     c->publish_aaaa_on_ipv4 = 1;
1587     c->publish_a_on_ipv6 = 0;
1588     c->n_cache_entries_max = AVAHI_DEFAULT_CACHE_ENTRIES_MAX;
1589
1590     return c;
1591 }
1592
1593 void avahi_server_config_free(AvahiServerConfig *c) {
1594     assert(c);
1595
1596     avahi_free(c->host_name);
1597     avahi_free(c->domain_name);
1598     avahi_string_list_free(c->browse_domains);
1599     avahi_string_list_free(c->allow_interfaces);
1600     avahi_string_list_free(c->deny_interfaces);
1601 }
1602
1603 AvahiServerConfig* avahi_server_config_copy(AvahiServerConfig *ret, const AvahiServerConfig *c) {
1604     char *d = NULL, *h = NULL;
1605     AvahiStringList *browse = NULL, *allow = NULL, *deny = NULL;
1606     assert(ret);
1607     assert(c);
1608
1609     if (c->host_name)
1610         if (!(h = avahi_strdup(c->host_name)))
1611             return NULL;
1612
1613     if (c->domain_name)
1614         if (!(d = avahi_strdup(c->domain_name))) {
1615             avahi_free(h);
1616             return NULL;
1617         }
1618
1619     if (!(browse = avahi_string_list_copy(c->browse_domains)) && c->browse_domains) {
1620         avahi_free(h);
1621         avahi_free(d);
1622         return NULL;
1623     }
1624
1625     if (!(allow = avahi_string_list_copy(c->allow_interfaces)) && c->allow_interfaces) {
1626         avahi_string_list_free(browse);
1627         avahi_free(h);
1628         avahi_free(d);
1629         return NULL;
1630     }
1631
1632     if (!(deny = avahi_string_list_copy(c->deny_interfaces)) && c->deny_interfaces) {
1633         avahi_string_list_free(allow);
1634         avahi_string_list_free(browse);
1635         avahi_free(h);
1636         avahi_free(d);
1637         return NULL;
1638     }
1639
1640     *ret = *c;
1641     ret->host_name = h;
1642     ret->domain_name = d;
1643     ret->browse_domains = browse;
1644     ret->allow_interfaces = allow;
1645     ret->deny_interfaces = deny;
1646
1647     return ret;
1648 }
1649
1650 int avahi_server_errno(AvahiServer *s) {
1651     assert(s);
1652
1653     return s->error;
1654 }
1655
1656 /* Just for internal use */
1657 int avahi_server_set_errno(AvahiServer *s, int error) {
1658     assert(s);
1659
1660     return s->error = error;
1661 }
1662
1663 uint32_t avahi_server_get_local_service_cookie(AvahiServer *s) {
1664     assert(s);
1665
1666     return s->local_service_cookie;
1667 }
1668
1669 static AvahiEntry *find_entry(AvahiServer *s, AvahiIfIndex interface, AvahiProtocol protocol, AvahiKey *key) {
1670     AvahiEntry *e;
1671
1672     assert(s);
1673     assert(key);
1674
1675     for (e = avahi_hashmap_lookup(s->entries_by_key, key); e; e = e->by_key_next)
1676
1677         if ((e->interface == interface || e->interface <= 0 || interface <= 0) &&
1678             (e->protocol == protocol || e->protocol == AVAHI_PROTO_UNSPEC || protocol == AVAHI_PROTO_UNSPEC) &&
1679             (!e->group || e->group->state == AVAHI_ENTRY_GROUP_ESTABLISHED || e->group->state == AVAHI_ENTRY_GROUP_REGISTERING))
1680
1681             return e;
1682
1683     return NULL;
1684 }
1685
1686 int avahi_server_get_group_of_service(AvahiServer *s, AvahiIfIndex interface, AvahiProtocol protocol, const char *name, const char *type, const char *domain, AvahiSEntryGroup** ret_group) {
1687     AvahiKey *key = NULL;
1688     AvahiEntry *e;
1689     int ret;
1690     char n[AVAHI_DOMAIN_NAME_MAX];
1691
1692     assert(s);
1693     assert(name);
1694     assert(type);
1695     assert(ret_group);
1696
1697     AVAHI_CHECK_VALIDITY(s, AVAHI_IF_VALID(interface), AVAHI_ERR_INVALID_INTERFACE);
1698     AVAHI_CHECK_VALIDITY(s, AVAHI_PROTO_VALID(protocol), AVAHI_ERR_INVALID_PROTOCOL);
1699     AVAHI_CHECK_VALIDITY(s, avahi_is_valid_service_name(name), AVAHI_ERR_INVALID_SERVICE_NAME);
1700     AVAHI_CHECK_VALIDITY(s, avahi_is_valid_service_type_strict(type), AVAHI_ERR_INVALID_SERVICE_TYPE);
1701     AVAHI_CHECK_VALIDITY(s, !domain || avahi_is_valid_domain_name(domain), AVAHI_ERR_INVALID_DOMAIN_NAME);
1702
1703     if ((ret = avahi_service_name_join(n, sizeof(n), name, type, domain) < 0))
1704         return avahi_server_set_errno(s, ret);
1705
1706     if (!(key = avahi_key_new(n, AVAHI_DNS_CLASS_IN, AVAHI_DNS_TYPE_SRV)))
1707         return avahi_server_set_errno(s, AVAHI_ERR_NO_MEMORY);
1708
1709     e = find_entry(s, interface, protocol, key);
1710     avahi_key_unref(key);
1711
1712     if (e) {
1713         *ret_group = e->group;
1714         return AVAHI_OK;
1715     }
1716
1717     return avahi_server_set_errno(s, AVAHI_ERR_NOT_FOUND);
1718 }
1719
1720 int avahi_server_is_service_local(AvahiServer *s, AvahiIfIndex interface, AvahiProtocol protocol, const char *name) {
1721     AvahiKey *key = NULL;
1722     AvahiEntry *e;
1723
1724     assert(s);
1725     assert(name);
1726
1727     if (!s->host_name_fqdn)
1728         return 0;
1729
1730     if (!(key = avahi_key_new(name, AVAHI_DNS_CLASS_IN, AVAHI_DNS_TYPE_SRV)))
1731         return 0;
1732
1733     e = find_entry(s, interface, protocol, key);
1734     avahi_key_unref(key);
1735
1736     if (!e)
1737         return 0;
1738
1739     return avahi_domain_equal(s->host_name_fqdn, e->record->data.srv.name);
1740 }
1741
1742 int avahi_server_is_record_local(AvahiServer *s, AvahiIfIndex interface, AvahiProtocol protocol, AvahiRecord *record) {
1743     AvahiEntry *e;
1744
1745     assert(s);
1746     assert(record);
1747
1748     for (e = avahi_hashmap_lookup(s->entries_by_key, record->key); e; e = e->by_key_next)
1749
1750         if ((e->interface == interface || e->interface <= 0 || interface <= 0) &&
1751             (e->protocol == protocol || e->protocol == AVAHI_PROTO_UNSPEC || protocol == AVAHI_PROTO_UNSPEC) &&
1752             (!e->group || e->group->state == AVAHI_ENTRY_GROUP_ESTABLISHED || e->group->state == AVAHI_ENTRY_GROUP_REGISTERING) &&
1753             avahi_record_equal_no_ttl(record, e->record))
1754             return 1;
1755
1756     return 0;
1757 }
1758
1759 /** Set the wide area DNS servers */
1760 int avahi_server_set_wide_area_servers(AvahiServer *s, const AvahiAddress *a, unsigned n) {
1761     assert(s);
1762
1763     if (!s->wide_area_lookup_engine)
1764         return avahi_server_set_errno(s, AVAHI_ERR_INVALID_CONFIG);
1765
1766     avahi_wide_area_set_servers(s->wide_area_lookup_engine, a, n);
1767     return AVAHI_OK;
1768 }
1769
1770 const AvahiServerConfig* avahi_server_get_config(AvahiServer *s) {
1771     assert(s);
1772
1773     return &s->config;
1774 }
1775
1776 /** Set the browsing domains */
1777 int avahi_server_set_browse_domains(AvahiServer *s, AvahiStringList *domains) {
1778     AvahiStringList *l;
1779
1780     assert(s);
1781
1782     for (l = s->config.browse_domains; l; l = l->next)
1783         if (!avahi_is_valid_domain_name((char*) l->text))
1784             return avahi_server_set_errno(s, AVAHI_ERR_INVALID_DOMAIN_NAME);
1785
1786     avahi_string_list_free(s->config.browse_domains);
1787     s->config.browse_domains = avahi_string_list_copy(domains);
1788
1789     return AVAHI_OK;
1790 }