2 This file is part of avahi.
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.
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.
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
28 #include <netinet/in.h>
30 #include <avahi-common/malloc.h>
31 #include <avahi-common/error.h>
32 #include <avahi-common/timeval.h>
39 #include "wide-area.h"
40 #include "addr-util.h"
43 #define CACHE_ENTRIES_MAX 500
45 typedef struct AvahiWideAreaCacheEntry AvahiWideAreaCacheEntry;
47 struct AvahiWideAreaCacheEntry {
48 AvahiWideAreaLookupEngine *engine;
51 struct timeval timestamp;
52 struct timeval expiry;
54 AvahiTimeEvent *time_event;
56 AVAHI_LLIST_FIELDS(AvahiWideAreaCacheEntry, by_key);
57 AVAHI_LLIST_FIELDS(AvahiWideAreaCacheEntry, cache);
60 struct AvahiWideAreaLookup {
61 AvahiWideAreaLookupEngine *engine;
64 uint32_t id; /* effectively just an uint16_t, but we need it as an index for a hash table */
65 AvahiTimeEvent *time_event;
67 AvahiKey *key, *cname_key;
70 AvahiDnsPacket *packet;
72 AvahiWideAreaLookupCallback callback;
75 AvahiAddress dns_server_used;
77 AVAHI_LLIST_FIELDS(AvahiWideAreaLookup, lookups);
78 AVAHI_LLIST_FIELDS(AvahiWideAreaLookup, by_key);
81 struct AvahiWideAreaLookupEngine {
85 AvahiWatch *watch_ipv4, *watch_ipv6;
90 AVAHI_LLIST_HEAD(AvahiWideAreaCacheEntry, cache);
91 AvahiHashmap *cache_by_key;
92 unsigned cache_n_entries;
95 AVAHI_LLIST_HEAD(AvahiWideAreaLookup, lookups);
96 AvahiHashmap *lookups_by_id;
97 AvahiHashmap *lookups_by_key;
101 AvahiAddress dns_servers[AVAHI_WIDE_AREA_SERVERS_MAX];
102 unsigned n_dns_servers;
103 unsigned current_dns_server;
106 static AvahiWideAreaLookup* find_lookup(AvahiWideAreaLookupEngine *e, uint16_t id) {
107 AvahiWideAreaLookup *l;
112 if (!(l = avahi_hashmap_lookup(e->lookups_by_id, &i)))
123 static int send_to_dns_server(AvahiWideAreaLookup *l, AvahiDnsPacket *p) {
129 if (l->engine->n_dns_servers <= 0)
132 assert(l->engine->current_dns_server < l->engine->n_dns_servers);
134 a = &l->engine->dns_servers[l->engine->current_dns_server];
135 l->dns_server_used = *a;
137 if (a->proto == AVAHI_PROTO_INET) {
139 if (l->engine->fd_ipv4 < 0)
142 return avahi_send_dns_packet_ipv4(l->engine->fd_ipv4, AVAHI_IF_UNSPEC, p, NULL, &a->data.ipv4, AVAHI_DNS_PORT);
145 assert(a->proto == AVAHI_PROTO_INET6);
147 if (l->engine->fd_ipv6 < 0)
150 return avahi_send_dns_packet_ipv6(l->engine->fd_ipv6, AVAHI_IF_UNSPEC, p, NULL, &a->data.ipv6, AVAHI_DNS_PORT);
154 static void next_dns_server(AvahiWideAreaLookupEngine *e) {
157 e->current_dns_server++;
159 if (e->current_dns_server >= e->n_dns_servers)
160 e->current_dns_server = 0;
163 static void lookup_stop(AvahiWideAreaLookup *l) {
169 avahi_time_event_free(l->time_event);
170 l->time_event = NULL;
174 static void sender_timeout_callback(AvahiTimeEvent *e, void *userdata) {
175 AvahiWideAreaLookup *l = userdata;
180 /* Try another DNS server after three retries */
181 if (l->n_send >= 3 && avahi_address_cmp(&l->engine->dns_servers[l->engine->current_dns_server], &l->dns_server_used) == 0) {
182 next_dns_server(l->engine);
184 if (avahi_address_cmp(&l->engine->dns_servers[l->engine->current_dns_server], &l->dns_server_used) == 0)
185 /* There is no other DNS server, fail */
189 if (l->n_send >= 6) {
190 avahi_log_warn(__FILE__": Query timed out.");
191 avahi_server_set_errno(l->engine->server, AVAHI_ERR_TIMEOUT);
192 l->callback(l->engine, AVAHI_BROWSER_FAILURE, AVAHI_LOOKUP_RESULT_WIDE_AREA, NULL, l->userdata);
198 send_to_dns_server(l, l->packet);
201 avahi_time_event_update(e, avahi_elapse_time(&tv, 1000, 0));
204 AvahiWideAreaLookup *avahi_wide_area_lookup_new(
205 AvahiWideAreaLookupEngine *e,
207 AvahiWideAreaLookupCallback callback,
211 AvahiWideAreaLookup *l, *t;
219 l = avahi_new(AvahiWideAreaLookup, 1);
222 l->key = avahi_key_ref(key);
223 l->cname_key = avahi_key_new_cname(l->key);
224 l->callback = callback;
225 l->userdata = userdata;
227 /* If more than 65K wide area quries are issued simultaneously,
228 * this will break. This should be limited by some higher level */
230 for (;; e->next_id++)
231 if (!find_lookup(e, e->next_id))
232 break; /* This ID is not yet used. */
234 l->id = e->next_id++;
236 /* We keep the packet around in case we need to repeat our query */
237 l->packet = avahi_dns_packet_new(0);
239 avahi_dns_packet_set_field(l->packet, AVAHI_DNS_FIELD_ID, (uint16_t) l->id);
240 avahi_dns_packet_set_field(l->packet, AVAHI_DNS_FIELD_FLAGS, AVAHI_DNS_FLAGS(0, 0, 0, 0, 1, 0, 0, 0, 0, 0));
242 p = avahi_dns_packet_append_key(l->packet, key, 0);
245 avahi_dns_packet_set_field(l->packet, AVAHI_DNS_FIELD_QDCOUNT, 1);
247 if (send_to_dns_server(l, l->packet) < 0) {
248 avahi_log_error(__FILE__": Failed to send packet.");
249 avahi_dns_packet_free(l->packet);
250 avahi_key_unref(l->key);
252 avahi_key_unref(l->cname_key);
259 l->time_event = avahi_time_event_new(e->server->time_event_queue, avahi_elapse_time(&tv, 500, 0), sender_timeout_callback, l);
261 avahi_hashmap_insert(e->lookups_by_id, &l->id, l);
263 t = avahi_hashmap_lookup(e->lookups_by_key, l->key);
264 AVAHI_LLIST_PREPEND(AvahiWideAreaLookup, by_key, t, l);
265 avahi_hashmap_replace(e->lookups_by_key, avahi_key_ref(l->key), t);
267 AVAHI_LLIST_PREPEND(AvahiWideAreaLookup, lookups, e->lookups, l);
272 static void lookup_destroy(AvahiWideAreaLookup *l) {
273 AvahiWideAreaLookup *t;
278 t = avahi_hashmap_lookup(l->engine->lookups_by_key, l->key);
279 AVAHI_LLIST_REMOVE(AvahiWideAreaLookup, by_key, t, l);
281 avahi_hashmap_replace(l->engine->lookups_by_key, avahi_key_ref(l->key), t);
283 avahi_hashmap_remove(l->engine->lookups_by_key, l->key);
285 AVAHI_LLIST_REMOVE(AvahiWideAreaLookup, lookups, l->engine->lookups, l);
287 avahi_hashmap_remove(l->engine->lookups_by_id, &l->id);
288 avahi_dns_packet_free(l->packet);
291 avahi_key_unref(l->key);
294 avahi_key_unref(l->cname_key);
299 void avahi_wide_area_lookup_free(AvahiWideAreaLookup *l) {
306 l->engine->cleanup_dead = 1;
310 void avahi_wide_area_cleanup(AvahiWideAreaLookupEngine *e) {
311 AvahiWideAreaLookup *l, *n;
314 while (e->cleanup_dead) {
317 for (l = e->lookups; l; l = n) {
326 static void cache_entry_free(AvahiWideAreaCacheEntry *c) {
327 AvahiWideAreaCacheEntry *t;
331 avahi_time_event_free(c->time_event);
333 AVAHI_LLIST_REMOVE(AvahiWideAreaCacheEntry, cache, c->engine->cache, c);
335 t = avahi_hashmap_lookup(c->engine->cache_by_key, c->record->key);
336 AVAHI_LLIST_REMOVE(AvahiWideAreaCacheEntry, by_key, t, c);
338 avahi_hashmap_replace(c->engine->cache_by_key, avahi_key_ref(c->record->key), t);
340 avahi_hashmap_remove(c->engine->cache_by_key, c->record->key);
342 c->engine->cache_n_entries --;
344 avahi_record_unref(c->record);
348 static void expiry_event(AvahiTimeEvent *te, void *userdata) {
349 AvahiWideAreaCacheEntry *e = userdata;
357 static AvahiWideAreaCacheEntry* find_record_in_cache(AvahiWideAreaLookupEngine *e, AvahiRecord *r) {
358 AvahiWideAreaCacheEntry *c;
363 for (c = avahi_hashmap_lookup(e->cache_by_key, r->key); c; c = c->by_key_next)
364 if (avahi_record_equal_no_ttl(r, c->record))
370 static void run_callbacks(AvahiWideAreaLookupEngine *e, AvahiRecord *r) {
371 AvahiWideAreaLookup *l;
376 for (l = avahi_hashmap_lookup(e->lookups_by_key, r->key); l; l = l->by_key_next) {
377 if (l->dead || !l->callback)
380 l->callback(e, AVAHI_BROWSER_NEW, AVAHI_LOOKUP_RESULT_WIDE_AREA, r, l->userdata);
383 if (r->key->clazz == AVAHI_DNS_CLASS_IN && r->key->type == AVAHI_DNS_TYPE_CNAME) {
384 /* It's a CNAME record, so we have to scan the all lookups to see if one matches */
386 for (l = e->lookups; l; l = l->lookups_next) {
389 if (l->dead || !l->callback)
392 if ((key = avahi_key_new_cname(l->key))) {
393 if (avahi_key_equal(r->key, key))
394 l->callback(e, AVAHI_BROWSER_NEW, AVAHI_LOOKUP_RESULT_WIDE_AREA, r, l->userdata);
396 avahi_key_unref(key);
402 static void add_to_cache(AvahiWideAreaLookupEngine *e, AvahiRecord *r) {
403 AvahiWideAreaCacheEntry *c;
409 if ((c = find_record_in_cache(e, r))) {
412 /* Update the existing entry */
413 avahi_record_unref(c->record);
415 AvahiWideAreaCacheEntry *t;
419 /* Enforce cache size */
420 if (e->cache_n_entries >= CACHE_ENTRIES_MAX)
421 /* Eventually we should improve the caching algorithm here */
424 c = avahi_new(AvahiWideAreaCacheEntry, 1);
426 c->time_event = NULL;
428 AVAHI_LLIST_PREPEND(AvahiWideAreaCacheEntry, cache, e->cache, c);
430 /* Add the new entry to the cache entry hash table */
431 t = avahi_hashmap_lookup(e->cache_by_key, r->key);
432 AVAHI_LLIST_PREPEND(AvahiWideAreaCacheEntry, by_key, t, c);
433 avahi_hashmap_replace(e->cache_by_key, avahi_key_ref(r->key), t);
435 e->cache_n_entries ++;
438 c->record = avahi_record_ref(r);
440 gettimeofday(&c->timestamp, NULL);
441 c->expiry = c->timestamp;
442 avahi_timeval_add(&c->expiry, r->ttl * 1000000);
445 avahi_time_event_update(c->time_event, &c->expiry);
447 c->time_event = avahi_time_event_new(e->server->time_event_queue, &c->expiry, expiry_event, c);
455 static int map_dns_error(uint16_t error) {
456 static const int table[16] = {
458 AVAHI_ERR_DNS_FORMERR,
459 AVAHI_ERR_DNS_SERVFAIL,
460 AVAHI_ERR_DNS_NXDOMAIN,
461 AVAHI_ERR_DNS_NOTIMP,
462 AVAHI_ERR_DNS_REFUSED,
463 AVAHI_ERR_DNS_YXDOMAIN,
464 AVAHI_ERR_DNS_YXRRSET,
465 AVAHI_ERR_DNS_NXRRSET,
466 AVAHI_ERR_DNS_NOTAUTH,
467 AVAHI_ERR_DNS_NOTZONE,
468 AVAHI_ERR_INVALID_DNS_ERROR,
469 AVAHI_ERR_INVALID_DNS_ERROR,
470 AVAHI_ERR_INVALID_DNS_ERROR,
471 AVAHI_ERR_INVALID_DNS_ERROR,
472 AVAHI_ERR_INVALID_DNS_ERROR
480 static void handle_packet(AvahiWideAreaLookupEngine *e, AvahiDnsPacket *p) {
481 AvahiWideAreaLookup *l = NULL;
484 AvahiBrowserEvent final_event = AVAHI_BROWSER_ALL_FOR_NOW;
489 /* Some superficial validity tests */
490 if (avahi_dns_packet_check_valid(p) < 0 || avahi_dns_packet_is_query(p)) {
491 avahi_log_warn(__FILE__": Ignoring invalid response for wide area datagram.");
495 /* Look for the lookup that issued this query */
496 if (!(l = find_lookup(e, avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_ID))) || l->dead)
499 /* Check whether this a packet indicating a failure */
500 if ((r = avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS) & 15) != 0 ||
501 avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_ANCOUNT) == 0) {
503 avahi_server_set_errno(e->server, r == 0 ? AVAHI_ERR_NOT_FOUND : map_dns_error(r));
504 /* Tell the user about the failure */
505 final_event = AVAHI_BROWSER_FAILURE;
507 /* We go on here, since some of the records contained in the
508 reply might be interesting in some way */
511 /* Skip over the question */
512 for (i = (int) avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_QDCOUNT); i > 0; i--) {
515 if (!(k = avahi_dns_packet_consume_key(p, NULL))) {
516 avahi_log_warn(__FILE__": Wide area response packet too short or invalid while reading question key. (Maybe a UTF-8 problem?)");
517 avahi_server_set_errno(e->server, AVAHI_ERR_INVALID_PACKET);
518 final_event = AVAHI_BROWSER_FAILURE;
525 /* Process responses */
526 for (i = (int) avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_ANCOUNT) +
527 (int) avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_NSCOUNT) +
528 (int) avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_ARCOUNT); i > 0; i--) {
532 if (!(rr = avahi_dns_packet_consume_record(p, NULL))) {
533 avahi_log_warn(__FILE__": Wide area response packet too short or invalid while reading response record. (Maybe a UTF-8 problem?)");
534 avahi_server_set_errno(e->server, AVAHI_ERR_INVALID_PACKET);
535 final_event = AVAHI_BROWSER_FAILURE;
540 avahi_record_unref(rr);
547 l->callback(e, final_event, AVAHI_LOOKUP_RESULT_WIDE_AREA, NULL, l->userdata);
553 static void socket_event(AVAHI_GCC_UNUSED AvahiWatch *w, int fd, AVAHI_GCC_UNUSED AvahiWatchEvent events, void *userdata) {
554 AvahiWideAreaLookupEngine *e = userdata;
555 AvahiDnsPacket *p = NULL;
557 if (fd == e->fd_ipv4)
558 p = avahi_recv_dns_packet_ipv4(e->fd_ipv4, NULL, NULL, NULL, NULL, NULL);
560 assert(fd == e->fd_ipv6);
561 p = avahi_recv_dns_packet_ipv6(e->fd_ipv6, NULL, NULL, NULL, NULL, NULL);
566 avahi_dns_packet_free(p);
570 AvahiWideAreaLookupEngine *avahi_wide_area_engine_new(AvahiServer *s) {
571 AvahiWideAreaLookupEngine *e;
575 e = avahi_new(AvahiWideAreaLookupEngine, 1);
580 e->fd_ipv4 = s->config.use_ipv4 ? avahi_open_unicast_socket_ipv4() : -1;
581 e->fd_ipv6 = s->config.use_ipv6 ? avahi_open_unicast_socket_ipv6() : -1;
583 if (e->fd_ipv4 < 0 && e->fd_ipv6 < 0) {
584 avahi_log_error(__FILE__": Failed to create wide area sockets: %s", strerror(errno));
598 e->watch_ipv4 = e->watch_ipv6 = NULL;
601 e->watch_ipv4 = s->poll_api->watch_new(e->server->poll_api, e->fd_ipv4, AVAHI_WATCH_IN, socket_event, e);
603 e->watch_ipv6 = s->poll_api->watch_new(e->server->poll_api, e->fd_ipv6, AVAHI_WATCH_IN, socket_event, e);
605 e->n_dns_servers = e->current_dns_server = 0;
606 e->next_id = (uint16_t) rand();
608 /* Initialize cache */
609 AVAHI_LLIST_HEAD_INIT(AvahiWideAreaCacheEntry, e->cache);
610 e->cache_by_key = avahi_hashmap_new((AvahiHashFunc) avahi_key_hash, (AvahiEqualFunc) avahi_key_equal, (AvahiFreeFunc) avahi_key_unref, NULL);
611 e->cache_n_entries = 0;
613 /* Initialize lookup list */
614 e->lookups_by_id = avahi_hashmap_new((AvahiHashFunc) avahi_int_hash, (AvahiEqualFunc) avahi_int_equal, NULL, NULL);
615 e->lookups_by_key = avahi_hashmap_new((AvahiHashFunc) avahi_key_hash, (AvahiEqualFunc) avahi_key_equal, (AvahiFreeFunc) avahi_key_unref, NULL);
616 AVAHI_LLIST_HEAD_INIT(AvahiWideAreaLookup, e->lookups);
621 void avahi_wide_area_engine_free(AvahiWideAreaLookupEngine *e) {
624 avahi_wide_area_clear_cache(e);
627 lookup_destroy(e->lookups);
629 avahi_hashmap_free(e->cache_by_key);
630 avahi_hashmap_free(e->lookups_by_id);
631 avahi_hashmap_free(e->lookups_by_key);
634 e->server->poll_api->watch_free(e->watch_ipv4);
637 e->server->poll_api->watch_free(e->watch_ipv6);
648 void avahi_wide_area_clear_cache(AvahiWideAreaLookupEngine *e) {
652 cache_entry_free(e->cache);
654 assert(e->cache_n_entries == 0);
657 void avahi_wide_area_set_servers(AvahiWideAreaLookupEngine *e, const AvahiAddress *a, unsigned n) {
661 for (e->n_dns_servers = 0; n > 0 && e->n_dns_servers < AVAHI_WIDE_AREA_SERVERS_MAX; a++, n--)
662 if ((a->proto == AVAHI_PROTO_INET && e->fd_ipv4 >= 0) || (a->proto == AVAHI_PROTO_INET6 && e->fd_ipv6 >= 0))
663 e->dns_servers[e->n_dns_servers++] = *a;
666 e->n_dns_servers = 0;
669 e->current_dns_server = 0;
671 avahi_wide_area_clear_cache(e);
674 void avahi_wide_area_cache_dump(AvahiWideAreaLookupEngine *e, AvahiDumpCallback callback, void* userdata) {
675 AvahiWideAreaCacheEntry *c;
680 callback(";; WIDE AREA CACHE ;;; ", userdata);
682 for (c = e->cache; c; c = c->cache_next) {
683 char *t = avahi_record_to_string(c->record);
684 callback(t, userdata);
689 unsigned avahi_wide_area_scan_cache(AvahiWideAreaLookupEngine *e, AvahiKey *key, AvahiWideAreaLookupCallback callback, void *userdata) {
690 AvahiWideAreaCacheEntry *c;
698 for (c = avahi_hashmap_lookup(e->cache_by_key, key); c; c = c->by_key_next) {
699 callback(e, AVAHI_BROWSER_NEW, AVAHI_LOOKUP_RESULT_WIDE_AREA|AVAHI_LOOKUP_RESULT_CACHED, c->record, userdata);
703 if ((cname_key = avahi_key_new_cname(key))) {
705 for (c = avahi_hashmap_lookup(e->cache_by_key, cname_key); c; c = c->by_key_next) {
706 callback(e, AVAHI_BROWSER_NEW, AVAHI_LOOKUP_RESULT_WIDE_AREA|AVAHI_LOOKUP_RESULT_CACHED, c->record, userdata);
710 avahi_key_unref(cname_key);
716 int avahi_wide_area_has_servers(AvahiWideAreaLookupEngine *e) {
719 return e->n_dns_servers > 0;