4 This file is part of avahi.
6 avahi is free software; you can redistribute it and/or modify it
7 under the terms of the GNU Lesser General Public License as
8 published by the Free Software Foundation; either version 2.1 of the
9 License, or (at your option) any later version.
11 avahi is distributed in the hope that it will be useful, but WITHOUT
12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
13 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
14 Public License for more details.
16 You should have received a copy of the GNU Lesser General Public
17 License along with avahi; if not, write to the Free Software
18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
31 #include <avahi-common/malloc.h>
32 #include <avahi-common/error.h>
33 #include <avahi-common/timeval.h>
40 #include "wide-area.h"
41 #include "addr-util.h"
44 #define CACHE_ENTRIES_MAX 500
46 typedef struct AvahiWideAreaCacheEntry AvahiWideAreaCacheEntry;
48 struct AvahiWideAreaCacheEntry {
49 AvahiWideAreaLookupEngine *engine;
52 struct timeval timestamp;
53 struct timeval expiry;
55 AvahiTimeEvent *time_event;
57 AVAHI_LLIST_FIELDS(AvahiWideAreaCacheEntry, by_key);
58 AVAHI_LLIST_FIELDS(AvahiWideAreaCacheEntry, cache);
61 struct AvahiWideAreaLookup {
62 AvahiWideAreaLookupEngine *engine;
65 uint32_t id; /* effectively just an uint16_t, but we need it as an index for a hash table */
66 AvahiTimeEvent *time_event;
68 AvahiKey *key, *cname_key;
71 AvahiDnsPacket *packet;
73 AvahiWideAreaLookupCallback callback;
76 AvahiAddress dns_server_used;
78 AVAHI_LLIST_FIELDS(AvahiWideAreaLookup, lookups);
79 AVAHI_LLIST_FIELDS(AvahiWideAreaLookup, by_key);
82 struct AvahiWideAreaLookupEngine {
86 AvahiWatch *watch_ipv4, *watch_ipv6;
91 AVAHI_LLIST_HEAD(AvahiWideAreaCacheEntry, cache);
92 AvahiHashmap *cache_by_key;
93 unsigned cache_n_entries;
96 AVAHI_LLIST_HEAD(AvahiWideAreaLookup, lookups);
97 AvahiHashmap *lookups_by_id;
98 AvahiHashmap *lookups_by_key;
102 AvahiAddress dns_servers[AVAHI_WIDE_AREA_SERVERS_MAX];
103 unsigned n_dns_servers;
104 unsigned current_dns_server;
107 static AvahiWideAreaLookup* find_lookup(AvahiWideAreaLookupEngine *e, uint16_t id) {
108 AvahiWideAreaLookup *l;
113 if (!(l = avahi_hashmap_lookup(e->lookups_by_id, &i)))
124 static int send_to_dns_server(AvahiWideAreaLookup *l, AvahiDnsPacket *p) {
130 if (l->engine->n_dns_servers <= 0)
133 assert(l->engine->current_dns_server < l->engine->n_dns_servers);
135 a = &l->engine->dns_servers[l->engine->current_dns_server];
136 l->dns_server_used = *a;
138 if (a->proto == AVAHI_PROTO_INET) {
140 if (l->engine->fd_ipv4 < 0)
143 return avahi_send_dns_packet_ipv4(l->engine->fd_ipv4, AVAHI_IF_UNSPEC, p, &a->data.ipv4, AVAHI_DNS_PORT);
146 assert(a->proto == AVAHI_PROTO_INET6);
148 if (l->engine->fd_ipv6 < 0)
151 return avahi_send_dns_packet_ipv6(l->engine->fd_ipv6, AVAHI_IF_UNSPEC, p, &a->data.ipv6, AVAHI_DNS_PORT);
155 static void next_dns_server(AvahiWideAreaLookupEngine *e) {
158 e->current_dns_server++;
160 if (e->current_dns_server >= e->n_dns_servers)
161 e->current_dns_server = 0;
164 static void sender_timeout_callback(AvahiTimeEvent *e, void *userdata) {
165 AvahiWideAreaLookup *l = userdata;
170 /* Try another DNS server after three retries */
171 if (l->n_send >= 3 && avahi_address_cmp(&l->engine->dns_servers[l->engine->current_dns_server], &l->dns_server_used) == 0) {
172 next_dns_server(l->engine);
174 if (avahi_address_cmp(&l->engine->dns_servers[l->engine->current_dns_server], &l->dns_server_used) == 0)
175 /* There is no other DNS server, fail */
179 if (l->n_send >= 6) {
180 avahi_log_warn(__FILE__": Query timed out.");
181 avahi_server_set_errno(l->engine->server, AVAHI_ERR_TIMEOUT);
182 l->callback(l->engine, AVAHI_BROWSER_FAILURE, AVAHI_LOOKUP_RESULT_WIDE_AREA, NULL, l->userdata);
183 avahi_wide_area_lookup_free(l);
188 send_to_dns_server(l, l->packet);
191 avahi_time_event_update(e, avahi_elapse_time(&tv, 1000, 0));
194 AvahiWideAreaLookup *avahi_wide_area_lookup_new(
195 AvahiWideAreaLookupEngine *e,
197 AvahiWideAreaLookupCallback callback,
201 AvahiWideAreaLookup *l, *t;
209 l = avahi_new(AvahiWideAreaLookup, 1);
212 l->key = avahi_key_ref(key);
213 l->cname_key = avahi_key_new_cname(l->key);
214 l->callback = callback;
215 l->userdata = userdata;
217 /* If more than 65K wide area quries are issued simultaneously,
218 * this will break. This should be limited by some higher level */
220 for (;; e->next_id++)
221 if (!find_lookup(e, e->next_id))
222 break; /* This ID is not yet used. */
224 l->id = e->next_id++;
226 /* We keep the packet around in case we need to repeat our query */
227 l->packet = avahi_dns_packet_new(0);
229 avahi_dns_packet_set_field(l->packet, AVAHI_DNS_FIELD_ID, (uint16_t) l->id);
230 avahi_dns_packet_set_field(l->packet, AVAHI_DNS_FIELD_FLAGS, AVAHI_DNS_FLAGS(0, 0, 0, 0, 1, 0, 0, 0, 0, 0));
232 p = avahi_dns_packet_append_key(l->packet, key, 0);
235 avahi_dns_packet_set_field(l->packet, AVAHI_DNS_FIELD_QDCOUNT, 1);
237 if (send_to_dns_server(l, l->packet) < 0) {
238 avahi_log_error(__FILE__": Failed to send packet.");
239 avahi_dns_packet_free(l->packet);
240 avahi_key_unref(l->key);
242 avahi_key_unref(l->cname_key);
249 l->time_event = avahi_time_event_new(e->server->time_event_queue, avahi_elapse_time(&tv, 500, 0), sender_timeout_callback, l);
251 avahi_hashmap_insert(e->lookups_by_id, &l->id, l);
253 t = avahi_hashmap_lookup(e->lookups_by_key, l->key);
254 AVAHI_LLIST_PREPEND(AvahiWideAreaLookup, by_key, t, l);
255 avahi_hashmap_replace(e->lookups_by_key, avahi_key_ref(l->key), t);
257 AVAHI_LLIST_PREPEND(AvahiWideAreaLookup, lookups, e->lookups, l);
262 static void lookup_stop(AvahiWideAreaLookup *l) {
268 avahi_time_event_free(l->time_event);
269 l->time_event = NULL;
273 static void lookup_destroy(AvahiWideAreaLookup *l) {
274 AvahiWideAreaLookup *t;
279 t = avahi_hashmap_lookup(l->engine->lookups_by_key, l->key);
280 AVAHI_LLIST_REMOVE(AvahiWideAreaLookup, by_key, t, l);
282 avahi_hashmap_replace(l->engine->lookups_by_key, avahi_key_ref(l->key), t);
284 avahi_hashmap_remove(l->engine->lookups_by_key, l->key);
286 AVAHI_LLIST_REMOVE(AvahiWideAreaLookup, lookups, l->engine->lookups, l);
288 avahi_hashmap_remove(l->engine->lookups_by_id, &l->id);
289 avahi_dns_packet_free(l->packet);
292 avahi_key_unref(l->key);
295 avahi_key_unref(l->cname_key);
300 void avahi_wide_area_lookup_free(AvahiWideAreaLookup *l) {
307 l->engine->cleanup_dead = 1;
311 void avahi_wide_area_cleanup(AvahiWideAreaLookupEngine *e) {
312 AvahiWideAreaLookup *l, *n;
315 while (e->cleanup_dead) {
318 for (l = e->lookups; l; l = n) {
327 static void cache_entry_free(AvahiWideAreaCacheEntry *c) {
328 AvahiWideAreaCacheEntry *t;
332 avahi_time_event_free(c->time_event);
334 AVAHI_LLIST_REMOVE(AvahiWideAreaCacheEntry, cache, c->engine->cache, c);
336 t = avahi_hashmap_lookup(c->engine->cache_by_key, c->record->key);
337 AVAHI_LLIST_REMOVE(AvahiWideAreaCacheEntry, by_key, t, c);
339 avahi_hashmap_replace(c->engine->cache_by_key, avahi_key_ref(c->record->key), t);
341 avahi_hashmap_remove(c->engine->cache_by_key, c->record->key);
343 c->engine->cache_n_entries --;
345 avahi_record_unref(c->record);
349 static void expiry_event(AvahiTimeEvent *te, void *userdata) {
350 AvahiWideAreaCacheEntry *e = userdata;
358 static AvahiWideAreaCacheEntry* find_record_in_cache(AvahiWideAreaLookupEngine *e, AvahiRecord *r) {
359 AvahiWideAreaCacheEntry *c;
364 for (c = avahi_hashmap_lookup(e->cache_by_key, r->key); c; c = c->by_key_next)
365 if (avahi_record_equal_no_ttl(r, c->record))
371 static void run_callbacks(AvahiWideAreaLookupEngine *e, AvahiRecord *r) {
372 AvahiWideAreaLookup *l;
377 for (l = avahi_hashmap_lookup(e->lookups_by_key, r->key); l; l = l->by_key_next) {
378 if (l->dead || !l->callback)
381 l->callback(e, AVAHI_BROWSER_NEW, AVAHI_LOOKUP_RESULT_WIDE_AREA, r, l->userdata);
384 if (r->key->clazz == AVAHI_DNS_CLASS_IN && r->key->type == AVAHI_DNS_TYPE_CNAME) {
385 /* It's a CNAME record, so we have to scan the all lookups to see if one matches */
387 for (l = e->lookups; l; l = l->lookups_next) {
390 if (l->dead || !l->callback)
393 if ((key = avahi_key_new_cname(l->key))) {
394 if (avahi_key_equal(r->key, key))
395 l->callback(e, AVAHI_BROWSER_NEW, AVAHI_LOOKUP_RESULT_WIDE_AREA, r, l->userdata);
397 avahi_key_unref(key);
403 static void add_to_cache(AvahiWideAreaLookupEngine *e, AvahiRecord *r) {
404 AvahiWideAreaCacheEntry *c;
410 if ((c = find_record_in_cache(e, r))) {
413 /* Update the existing entry */
414 avahi_record_unref(c->record);
416 AvahiWideAreaCacheEntry *t;
420 /* Enforce cache size */
421 if (e->cache_n_entries >= CACHE_ENTRIES_MAX)
422 /* Eventually we should improve the caching algorithm here */
425 c = avahi_new(AvahiWideAreaCacheEntry, 1);
427 c->time_event = NULL;
429 AVAHI_LLIST_PREPEND(AvahiWideAreaCacheEntry, cache, e->cache, c);
431 /* Add the new entry to the cache entry hash table */
432 t = avahi_hashmap_lookup(e->cache_by_key, r->key);
433 AVAHI_LLIST_PREPEND(AvahiWideAreaCacheEntry, by_key, t, c);
434 avahi_hashmap_replace(e->cache_by_key, avahi_key_ref(r->key), t);
436 e->cache_n_entries ++;
439 c->record = avahi_record_ref(r);
441 gettimeofday(&c->timestamp, NULL);
442 c->expiry = c->timestamp;
443 avahi_timeval_add(&c->expiry, r->ttl * 1000000);
446 avahi_time_event_update(c->time_event, &c->expiry);
448 c->time_event = avahi_time_event_new(e->server->time_event_queue, &c->expiry, expiry_event, c);
456 static int map_dns_error(uint16_t error) {
457 static const int table[16] = {
459 AVAHI_ERR_DNS_FORMERR,
460 AVAHI_ERR_DNS_SERVFAIL,
461 AVAHI_ERR_DNS_NXDOMAIN,
462 AVAHI_ERR_DNS_NOTIMP,
463 AVAHI_ERR_DNS_REFUSED,
464 AVAHI_ERR_DNS_YXDOMAIN,
465 AVAHI_ERR_DNS_YXRRSET,
466 AVAHI_ERR_DNS_NXRRSET,
467 AVAHI_ERR_DNS_NOTAUTH,
468 AVAHI_ERR_DNS_NOTZONE,
469 AVAHI_ERR_INVALID_DNS_ERROR,
470 AVAHI_ERR_INVALID_DNS_ERROR,
471 AVAHI_ERR_INVALID_DNS_ERROR,
472 AVAHI_ERR_INVALID_DNS_ERROR,
473 AVAHI_ERR_INVALID_DNS_ERROR
481 static void handle_packet(AvahiWideAreaLookupEngine *e, AvahiDnsPacket *p) {
482 AvahiWideAreaLookup *l = NULL;
485 AvahiBrowserEvent final_event = AVAHI_BROWSER_ALL_FOR_NOW;
490 /* Some superficial validity tests */
491 if (avahi_dns_packet_check_valid(p) < 0 || avahi_dns_packet_is_query(p)) {
492 avahi_log_warn(__FILE__": Ignoring invalid response for wide area datagram.");
496 /* Look for the lookup that issued this query */
497 if (!(l = find_lookup(e, avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_ID))) || l->dead)
500 /* Check whether this a packet indicating a failure */
501 if ((r = avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS) & 15) != 0 ||
502 avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_ANCOUNT) == 0) {
504 avahi_server_set_errno(e->server, r == 0 ? AVAHI_ERR_NOT_FOUND : map_dns_error(r));
505 /* Tell the user about the failure */
506 final_event = AVAHI_BROWSER_FAILURE;
508 /* We go on here, since some of the records contained in the
509 reply might be interesting in some way */
512 /* Skip over the question */
513 for (i = (int) avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_QDCOUNT); i > 0; i--) {
516 if (!(k = avahi_dns_packet_consume_key(p, NULL))) {
517 avahi_log_warn(__FILE__": Wide area response packet too short.");
518 avahi_server_set_errno(e->server, AVAHI_ERR_INVALID_PACKET);
519 final_event = AVAHI_BROWSER_FAILURE;
526 /* Process responses */
527 for (i = (int) avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_ANCOUNT) +
528 (int) avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_NSCOUNT) +
529 (int) avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_ARCOUNT); i > 0; i--) {
533 if (!(rr = avahi_dns_packet_consume_record(p, NULL))) {
534 avahi_log_warn(__FILE__": Wide area response packet too short (2).");
535 avahi_server_set_errno(e->server, AVAHI_ERR_INVALID_PACKET);
536 final_event = AVAHI_BROWSER_FAILURE;
541 avahi_record_unref(rr);
548 l->callback(e, final_event, AVAHI_LOOKUP_RESULT_WIDE_AREA, NULL, l->userdata);
554 static void socket_event(AVAHI_GCC_UNUSED AvahiWatch *w, int fd, AVAHI_GCC_UNUSED AvahiWatchEvent events, void *userdata) {
555 AvahiWideAreaLookupEngine *e = userdata;
557 AvahiDnsPacket *p = NULL;
559 if (fd == e->fd_ipv4) {
560 struct sockaddr_in sa;
562 if ((p = avahi_recv_dns_packet_ipv4(e->fd_ipv4, &sa, NULL, NULL, NULL)))
563 avahi_address_from_sockaddr((struct sockaddr*) &sa, &a);
565 } else if (fd == e->fd_ipv6) {
566 struct sockaddr_in6 sa6;
568 if ((p = avahi_recv_dns_packet_ipv6(e->fd_ipv6, &sa6, NULL, NULL, NULL)))
569 avahi_address_from_sockaddr((struct sockaddr*) &sa6, &a);
575 avahi_dns_packet_free(p);
579 AvahiWideAreaLookupEngine *avahi_wide_area_engine_new(AvahiServer *s) {
580 AvahiWideAreaLookupEngine *e;
584 e = avahi_new(AvahiWideAreaLookupEngine, 1);
589 e->fd_ipv4 = avahi_open_unicast_socket_ipv4();
590 e->fd_ipv6 = avahi_open_unicast_socket_ipv6();
592 if (e->fd_ipv4 < 0 && e->fd_ipv6 < 0) {
593 avahi_log_error(__FILE__": Failed to create wide area sockets: %s", strerror(errno));
607 e->watch_ipv4 = s->poll_api->watch_new(e->server->poll_api, e->fd_ipv4, AVAHI_WATCH_IN, socket_event, e);
609 e->watch_ipv6 = s->poll_api->watch_new(e->server->poll_api, e->fd_ipv6, AVAHI_WATCH_IN, socket_event, e);
611 e->n_dns_servers = e->current_dns_server = 0;
612 e->next_id = (uint16_t) rand();
614 /* Initialize cache */
615 AVAHI_LLIST_HEAD_INIT(AvahiWideAreaCacheEntry, e->cache);
616 e->cache_by_key = avahi_hashmap_new((AvahiHashFunc) avahi_key_hash, (AvahiEqualFunc) avahi_key_equal, (AvahiFreeFunc) avahi_key_unref, NULL);
617 e->cache_n_entries = 0;
619 /* Initialize lookup list */
620 e->lookups_by_id = avahi_hashmap_new((AvahiHashFunc) avahi_int_hash, (AvahiEqualFunc) avahi_int_equal, NULL, NULL);
621 e->lookups_by_key = avahi_hashmap_new((AvahiHashFunc) avahi_key_hash, (AvahiEqualFunc) avahi_key_equal, (AvahiFreeFunc) avahi_key_unref, NULL);
622 AVAHI_LLIST_HEAD_INIT(AvahiWideAreaLookup, e->lookups);
627 void avahi_wide_area_engine_free(AvahiWideAreaLookupEngine *e) {
630 avahi_wide_area_clear_cache(e);
633 lookup_destroy(e->lookups);
635 avahi_hashmap_free(e->cache_by_key);
636 avahi_hashmap_free(e->lookups_by_id);
637 avahi_hashmap_free(e->lookups_by_key);
640 e->server->poll_api->watch_free(e->watch_ipv4);
643 e->server->poll_api->watch_free(e->watch_ipv6);
654 void avahi_wide_area_clear_cache(AvahiWideAreaLookupEngine *e) {
658 cache_entry_free(e->cache);
660 assert(e->cache_n_entries == 0);
663 void avahi_wide_area_set_servers(AvahiWideAreaLookupEngine *e, const AvahiAddress *a, unsigned n) {
667 for (e->n_dns_servers = 0; n > 0 && e->n_dns_servers < AVAHI_WIDE_AREA_SERVERS_MAX; a++, n--)
668 if ((a->proto == AVAHI_PROTO_INET && e->fd_ipv4 >= 0) || (a->proto == AVAHI_PROTO_INET6 && e->fd_ipv6 >= 0))
669 e->dns_servers[e->n_dns_servers++] = *a;
672 e->n_dns_servers = 0;
675 e->current_dns_server = 0;
677 avahi_wide_area_clear_cache(e);
680 void avahi_wide_area_cache_dump(AvahiWideAreaLookupEngine *e, AvahiDumpCallback callback, void* userdata) {
681 AvahiWideAreaCacheEntry *c;
686 callback(";; WIDE AREA CACHE ;;; ", userdata);
688 for (c = e->cache; c; c = c->cache_next) {
689 char *t = avahi_record_to_string(c->record);
690 callback(t, userdata);
695 unsigned avahi_wide_area_scan_cache(AvahiWideAreaLookupEngine *e, AvahiKey *key, AvahiWideAreaLookupCallback callback, void *userdata) {
696 AvahiWideAreaCacheEntry *c;
704 for (c = avahi_hashmap_lookup(e->cache_by_key, key); c; c = c->by_key_next) {
705 callback(e, AVAHI_BROWSER_NEW, AVAHI_LOOKUP_RESULT_WIDE_AREA|AVAHI_LOOKUP_RESULT_CACHED, c->record, userdata);
709 if ((cname_key = avahi_key_new_cname(key))) {
711 for (c = avahi_hashmap_lookup(e->cache_by_key, cname_key); c; c = c->by_key_next) {
712 callback(e, AVAHI_BROWSER_NEW, AVAHI_LOOKUP_RESULT_WIDE_AREA|AVAHI_LOOKUP_RESULT_CACHED, c->record, userdata);
716 avahi_key_unref(cname_key);
722 int avahi_wide_area_has_servers(AvahiWideAreaLookupEngine *e) {
725 return e->n_dns_servers > 0;