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"
42 #define CACHE_ENTRIES_MAX 500
44 typedef struct AvahiWideAreaCacheEntry AvahiWideAreaCacheEntry;
46 struct AvahiWideAreaCacheEntry {
47 AvahiWideAreaLookupEngine *engine;
50 struct timeval timestamp;
51 struct timeval expiry;
53 AvahiTimeEvent *time_event;
55 AVAHI_LLIST_FIELDS(AvahiWideAreaCacheEntry, by_key);
56 AVAHI_LLIST_FIELDS(AvahiWideAreaCacheEntry, cache);
59 struct AvahiWideAreaLookup {
60 AvahiWideAreaLookupEngine *engine;
63 uint32_t id; /* effectively just an uint16_t, but we need it as an index for a hash table */
64 AvahiTimeEvent *time_event;
66 AvahiKey *key, *cname_key;
69 AvahiDnsPacket *packet;
71 AvahiWideAreaLookupCallback callback;
74 AvahiAddress dns_server_used;
76 AVAHI_LLIST_FIELDS(AvahiWideAreaLookup, lookups);
77 AVAHI_LLIST_FIELDS(AvahiWideAreaLookup, by_key);
80 struct AvahiWideAreaLookupEngine {
84 AvahiWatch *watch_ipv4, *watch_ipv6;
89 AVAHI_LLIST_HEAD(AvahiWideAreaCacheEntry, cache);
90 AvahiHashmap *cache_by_key;
91 unsigned cache_n_entries;
94 AVAHI_LLIST_HEAD(AvahiWideAreaLookup, lookups);
95 AvahiHashmap *lookups_by_id;
96 AvahiHashmap *lookups_by_key;
100 AvahiAddress dns_servers[AVAHI_WIDE_AREA_SERVERS_MAX];
101 unsigned n_dns_servers;
102 unsigned current_dns_server;
105 static AvahiWideAreaLookup* find_lookup(AvahiWideAreaLookupEngine *e, uint16_t id) {
106 AvahiWideAreaLookup *l;
111 if (!(l = avahi_hashmap_lookup(e->lookups_by_id, &i)))
122 static int send_to_dns_server(AvahiWideAreaLookup *l, AvahiDnsPacket *p) {
128 if (l->engine->n_dns_servers <= 0)
131 assert(l->engine->current_dns_server < l->engine->n_dns_servers);
133 a = &l->engine->dns_servers[l->engine->current_dns_server];
134 l->dns_server_used = *a;
136 if (a->proto == AVAHI_PROTO_INET) {
138 if (l->engine->fd_ipv4 < 0)
141 return avahi_send_dns_packet_ipv4(l->engine->fd_ipv4, AVAHI_IF_UNSPEC, p, &a->data.ipv4, AVAHI_DNS_PORT);
144 assert(a->proto == AVAHI_PROTO_INET6);
146 if (l->engine->fd_ipv6 < 0)
149 return avahi_send_dns_packet_ipv6(l->engine->fd_ipv6, AVAHI_IF_UNSPEC, p, &a->data.ipv6, AVAHI_DNS_PORT);
153 static void next_dns_server(AvahiWideAreaLookupEngine *e) {
156 e->current_dns_server++;
158 if (e->current_dns_server >= e->n_dns_servers)
159 e->current_dns_server = 0;
162 static void sender_timeout_callback(AvahiTimeEvent *e, void *userdata) {
163 AvahiWideAreaLookup *l = userdata;
168 /* Try another DNS server after three retries */
169 if (l->n_send >= 3 && avahi_address_cmp(&l->engine->dns_servers[l->engine->current_dns_server], &l->dns_server_used) == 0) {
170 next_dns_server(l->engine);
172 if (avahi_address_cmp(&l->engine->dns_servers[l->engine->current_dns_server], &l->dns_server_used) == 0)
173 /* There is no other DNS server, fail */
177 if (l->n_send >= 6) {
178 avahi_log_warn(__FILE__": Query timed out.");
179 avahi_server_set_errno(l->engine->server, AVAHI_ERR_TIMEOUT);
180 l->callback(l->engine, AVAHI_BROWSER_FAILURE, AVAHI_LOOKUP_RESULT_WIDE_AREA, NULL, l->userdata);
181 avahi_wide_area_lookup_free(l);
186 send_to_dns_server(l, l->packet);
189 avahi_time_event_update(e, avahi_elapse_time(&tv, 1000, 0));
192 AvahiWideAreaLookup *avahi_wide_area_lookup_new(
193 AvahiWideAreaLookupEngine *e,
195 AvahiWideAreaLookupCallback callback,
199 AvahiWideAreaLookup *l, *t;
207 l = avahi_new(AvahiWideAreaLookup, 1);
210 l->key = avahi_key_ref(key);
211 l->cname_key = avahi_key_new_cname(l->key);
212 l->callback = callback;
213 l->userdata = userdata;
215 /* If more than 65K wide area quries are issued simultaneously,
216 * this will break. This should be limited by some higher level */
218 for (;; e->next_id++)
219 if (!find_lookup(e, e->next_id))
220 break; /* This ID is not yet used. */
222 l->id = e->next_id++;
224 /* We keep the packet around in case we need to repeat our query */
225 l->packet = avahi_dns_packet_new(0);
227 avahi_dns_packet_set_field(l->packet, AVAHI_DNS_FIELD_ID, (uint16_t) l->id);
228 avahi_dns_packet_set_field(l->packet, AVAHI_DNS_FIELD_FLAGS, AVAHI_DNS_FLAGS(0, 0, 0, 0, 1, 0, 0, 0, 0, 0));
230 p = avahi_dns_packet_append_key(l->packet, key, 0);
233 avahi_dns_packet_set_field(l->packet, AVAHI_DNS_FIELD_QDCOUNT, 1);
235 if (send_to_dns_server(l, l->packet) < 0) {
236 avahi_log_error(__FILE__": Failed to send packet.");
237 avahi_dns_packet_free(l->packet);
238 avahi_key_unref(l->key);
240 avahi_key_unref(l->cname_key);
247 l->time_event = avahi_time_event_new(e->server->time_event_queue, avahi_elapse_time(&tv, 500, 0), sender_timeout_callback, l);
249 avahi_hashmap_insert(e->lookups_by_id, &l->id, l);
251 t = avahi_hashmap_lookup(e->lookups_by_key, l->key);
252 AVAHI_LLIST_PREPEND(AvahiWideAreaLookup, by_key, t, l);
253 avahi_hashmap_replace(e->lookups_by_key, avahi_key_ref(l->key), t);
255 AVAHI_LLIST_PREPEND(AvahiWideAreaLookup, lookups, e->lookups, l);
260 static void lookup_stop(AvahiWideAreaLookup *l) {
266 avahi_time_event_free(l->time_event);
267 l->time_event = NULL;
271 static void lookup_destroy(AvahiWideAreaLookup *l) {
272 AvahiWideAreaLookup *t;
277 t = avahi_hashmap_lookup(l->engine->lookups_by_key, l->key);
278 AVAHI_LLIST_REMOVE(AvahiWideAreaLookup, by_key, t, l);
280 avahi_hashmap_replace(l->engine->lookups_by_key, avahi_key_ref(l->key), t);
282 avahi_hashmap_remove(l->engine->lookups_by_key, l->key);
284 AVAHI_LLIST_REMOVE(AvahiWideAreaLookup, lookups, l->engine->lookups, l);
286 avahi_hashmap_remove(l->engine->lookups_by_id, &l->id);
287 avahi_dns_packet_free(l->packet);
290 avahi_key_unref(l->key);
293 avahi_key_unref(l->cname_key);
298 void avahi_wide_area_lookup_free(AvahiWideAreaLookup *l) {
305 l->engine->cleanup_dead = 1;
309 void avahi_wide_area_cleanup(AvahiWideAreaLookupEngine *e) {
310 AvahiWideAreaLookup *l, *n;
313 while (e->cleanup_dead) {
316 for (l = e->lookups; l; l = n) {
325 static void cache_entry_free(AvahiWideAreaCacheEntry *c) {
326 AvahiWideAreaCacheEntry *t;
330 avahi_time_event_free(c->time_event);
332 AVAHI_LLIST_REMOVE(AvahiWideAreaCacheEntry, cache, c->engine->cache, c);
334 t = avahi_hashmap_lookup(c->engine->cache_by_key, c->record->key);
335 AVAHI_LLIST_REMOVE(AvahiWideAreaCacheEntry, by_key, t, c);
337 avahi_hashmap_replace(c->engine->cache_by_key, avahi_key_ref(c->record->key), t);
339 avahi_hashmap_remove(c->engine->cache_by_key, c->record->key);
341 c->engine->cache_n_entries --;
343 avahi_record_unref(c->record);
347 static void expiry_event(AvahiTimeEvent *te, void *userdata) {
348 AvahiWideAreaCacheEntry *e = userdata;
356 static AvahiWideAreaCacheEntry* find_record_in_cache(AvahiWideAreaLookupEngine *e, AvahiRecord *r) {
357 AvahiWideAreaCacheEntry *c;
362 for (c = avahi_hashmap_lookup(e->cache_by_key, r->key); c; c = c->by_key_next)
363 if (avahi_record_equal_no_ttl(r, c->record))
369 static void run_callbacks(AvahiWideAreaLookupEngine *e, AvahiRecord *r) {
370 AvahiWideAreaLookup *l;
375 for (l = avahi_hashmap_lookup(e->lookups_by_key, r->key); l; l = l->by_key_next) {
376 if (l->dead || !l->callback)
379 l->callback(e, AVAHI_BROWSER_NEW, AVAHI_LOOKUP_RESULT_WIDE_AREA, r, l->userdata);
382 if (r->key->clazz == AVAHI_DNS_CLASS_IN && r->key->type == AVAHI_DNS_TYPE_CNAME) {
383 /* It's a CNAME record, so we have to scan the all lookups to see if one matches */
385 for (l = e->lookups; l; l = l->lookups_next) {
388 if (l->dead || !l->callback)
391 if ((key = avahi_key_new_cname(l->key))) {
392 if (avahi_key_equal(r->key, key))
393 l->callback(e, AVAHI_BROWSER_NEW, AVAHI_LOOKUP_RESULT_WIDE_AREA, r, l->userdata);
395 avahi_key_unref(key);
401 static void add_to_cache(AvahiWideAreaLookupEngine *e, AvahiRecord *r) {
402 AvahiWideAreaCacheEntry *c;
408 if ((c = find_record_in_cache(e, r))) {
411 /* Update the existing entry */
412 avahi_record_unref(c->record);
414 AvahiWideAreaCacheEntry *t;
418 /* Enforce cache size */
419 if (e->cache_n_entries >= CACHE_ENTRIES_MAX)
420 /* Eventually we should improve the caching algorithm here */
423 c = avahi_new(AvahiWideAreaCacheEntry, 1);
425 c->time_event = NULL;
427 AVAHI_LLIST_PREPEND(AvahiWideAreaCacheEntry, cache, e->cache, c);
429 /* Add the new entry to the cache entry hash table */
430 t = avahi_hashmap_lookup(e->cache_by_key, r->key);
431 AVAHI_LLIST_PREPEND(AvahiWideAreaCacheEntry, by_key, t, c);
432 avahi_hashmap_replace(e->cache_by_key, avahi_key_ref(r->key), t);
434 e->cache_n_entries ++;
437 c->record = avahi_record_ref(r);
439 gettimeofday(&c->timestamp, NULL);
440 c->expiry = c->timestamp;
441 avahi_timeval_add(&c->expiry, r->ttl * 1000000);
444 avahi_time_event_update(c->time_event, &c->expiry);
446 c->time_event = avahi_time_event_new(e->server->time_event_queue, &c->expiry, expiry_event, c);
454 static int map_dns_error(uint16_t error) {
455 static const int table[16] = {
457 AVAHI_ERR_DNS_FORMERR,
458 AVAHI_ERR_DNS_SERVFAIL,
459 AVAHI_ERR_DNS_NXDOMAIN,
460 AVAHI_ERR_DNS_NOTIMP,
461 AVAHI_ERR_DNS_REFUSED,
462 AVAHI_ERR_DNS_YXDOMAIN,
463 AVAHI_ERR_DNS_YXRRSET,
464 AVAHI_ERR_DNS_NXRRSET,
465 AVAHI_ERR_DNS_NOTAUTH,
466 AVAHI_ERR_DNS_NOTZONE,
467 AVAHI_ERR_INVALID_DNS_ERROR,
468 AVAHI_ERR_INVALID_DNS_ERROR,
469 AVAHI_ERR_INVALID_DNS_ERROR,
470 AVAHI_ERR_INVALID_DNS_ERROR,
471 AVAHI_ERR_INVALID_DNS_ERROR
479 static void handle_packet(AvahiWideAreaLookupEngine *e, AvahiDnsPacket *p, AvahiAddress *a) {
480 AvahiWideAreaLookup *l = NULL;
483 AvahiBrowserEvent final_event = AVAHI_BROWSER_ALL_FOR_NOW;
488 /* Some superficial validity tests */
489 if (avahi_dns_packet_check_valid(p) < 0 || avahi_dns_packet_is_query(p)) {
490 avahi_log_warn(__FILE__": Ignoring invalid response for wide area datagram.");
494 /* Look for the lookup that issued this query */
495 if (!(l = find_lookup(e, avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_ID))) || l->dead)
498 /* Check whether this a packet indicating a failure */
499 if ((r = avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS) & 15) != 0 ||
500 avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_ANCOUNT) == 0) {
502 avahi_server_set_errno(e->server, r == 0 ? AVAHI_ERR_NOT_FOUND : map_dns_error(r));
503 /* Tell the user about the failure */
504 final_event = AVAHI_BROWSER_FAILURE;
506 /* We go on here, since some of the records contained in the
507 reply might be interesting in some way */
510 /* Skip over the question */
511 for (i = (int) avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_QDCOUNT); i > 0; i--) {
514 if (!(k = avahi_dns_packet_consume_key(p, NULL))) {
515 avahi_log_warn(__FILE__": Wide area response packet too short.");
516 avahi_server_set_errno(e->server, AVAHI_ERR_INVALID_PACKET);
517 final_event = AVAHI_BROWSER_FAILURE;
524 /* Process responses */
525 for (i = (int) avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_ANCOUNT) +
526 (int) avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_NSCOUNT) +
527 (int) avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_ARCOUNT); i > 0; i--) {
531 if (!(rr = avahi_dns_packet_consume_record(p, NULL))) {
532 avahi_log_warn(__FILE__": Wide area response packet too short (2).");
533 avahi_server_set_errno(e->server, AVAHI_ERR_INVALID_PACKET);
534 final_event = AVAHI_BROWSER_FAILURE;
539 avahi_record_unref(rr);
546 l->callback(e, final_event, AVAHI_LOOKUP_RESULT_WIDE_AREA, NULL, l->userdata);
552 static void socket_event(AvahiWatch *w, int fd, AvahiWatchEvent events, void *userdata) {
553 AvahiWideAreaLookupEngine *e = userdata;
555 AvahiDnsPacket *p = NULL;
557 if (fd == e->fd_ipv4) {
558 struct sockaddr_in sa;
560 if ((p = avahi_recv_dns_packet_ipv4(e->fd_ipv4, &sa, NULL, NULL, NULL)))
561 avahi_address_from_sockaddr((struct sockaddr*) &sa, &a);
563 } else if (fd == e->fd_ipv6) {
564 struct sockaddr_in6 sa6;
566 if ((p = avahi_recv_dns_packet_ipv6(e->fd_ipv6, &sa6, NULL, NULL, NULL)))
567 avahi_address_from_sockaddr((struct sockaddr*) &sa6, &a);
572 handle_packet(e, p, &a);
573 avahi_dns_packet_free(p);
577 AvahiWideAreaLookupEngine *avahi_wide_area_engine_new(AvahiServer *s) {
578 AvahiWideAreaLookupEngine *e;
582 e = avahi_new(AvahiWideAreaLookupEngine, 1);
587 e->fd_ipv4 = avahi_open_unicast_socket_ipv4();
588 e->fd_ipv6 = avahi_open_unicast_socket_ipv6();
590 if (e->fd_ipv4 < 0 && e->fd_ipv6 < 0) {
591 avahi_log_error(__FILE__": Failed to create wide area sockets: %s", strerror(errno));
605 e->watch_ipv4 = s->poll_api->watch_new(e->server->poll_api, e->fd_ipv4, AVAHI_WATCH_IN, socket_event, e);
607 e->watch_ipv6 = s->poll_api->watch_new(e->server->poll_api, e->fd_ipv6, AVAHI_WATCH_IN, socket_event, e);
609 e->n_dns_servers = e->current_dns_server = 0;
610 e->next_id = (uint16_t) rand();
612 /* Initialize cache */
613 AVAHI_LLIST_HEAD_INIT(AvahiWideAreaCacheEntry, e->cache);
614 e->cache_by_key = avahi_hashmap_new((AvahiHashFunc) avahi_key_hash, (AvahiEqualFunc) avahi_key_equal, (AvahiFreeFunc) avahi_key_unref, NULL);
615 e->cache_n_entries = 0;
617 /* Initialize lookup list */
618 e->lookups_by_id = avahi_hashmap_new((AvahiHashFunc) avahi_int_hash, (AvahiEqualFunc) avahi_int_equal, NULL, NULL);
619 e->lookups_by_key = avahi_hashmap_new((AvahiHashFunc) avahi_key_hash, (AvahiEqualFunc) avahi_key_equal, (AvahiFreeFunc) avahi_key_unref, NULL);
620 AVAHI_LLIST_HEAD_INIT(AvahiWideAreaLookup, e->lookups);
625 void avahi_wide_area_engine_free(AvahiWideAreaLookupEngine *e) {
628 avahi_wide_area_clear_cache(e);
631 lookup_destroy(e->lookups);
633 avahi_hashmap_free(e->cache_by_key);
634 avahi_hashmap_free(e->lookups_by_id);
635 avahi_hashmap_free(e->lookups_by_key);
638 e->server->poll_api->watch_free(e->watch_ipv4);
641 e->server->poll_api->watch_free(e->watch_ipv6);
652 void avahi_wide_area_clear_cache(AvahiWideAreaLookupEngine *e) {
656 cache_entry_free(e->cache);
658 assert(e->cache_n_entries == 0);
661 void avahi_wide_area_set_servers(AvahiWideAreaLookupEngine *e, const AvahiAddress *a, unsigned n) {
665 for (e->n_dns_servers = 0; n > 0 && e->n_dns_servers < AVAHI_WIDE_AREA_SERVERS_MAX; a++, n--)
666 if ((a->proto == AVAHI_PROTO_INET && e->fd_ipv4 >= 0) || (a->proto == AVAHI_PROTO_INET6 && e->fd_ipv6 >= 0))
667 e->dns_servers[e->n_dns_servers++] = *a;
670 e->n_dns_servers = 0;
673 e->current_dns_server = 0;
675 avahi_wide_area_clear_cache(e);
678 void avahi_wide_area_cache_dump(AvahiWideAreaLookupEngine *e, AvahiDumpCallback callback, void* userdata) {
679 AvahiWideAreaCacheEntry *c;
684 callback(";; WIDE AREA CACHE ;;; ", userdata);
686 for (c = e->cache; c; c = c->cache_next) {
687 char *t = avahi_record_to_string(c->record);
688 callback(t, userdata);
693 unsigned avahi_wide_area_scan_cache(AvahiWideAreaLookupEngine *e, AvahiKey *key, AvahiWideAreaLookupCallback callback, void *userdata) {
694 AvahiWideAreaCacheEntry *c;
702 for (c = avahi_hashmap_lookup(e->cache_by_key, key); c; c = c->by_key_next) {
703 callback(e, AVAHI_BROWSER_NEW, AVAHI_LOOKUP_RESULT_WIDE_AREA|AVAHI_LOOKUP_RESULT_CACHED, c->record, userdata);
707 if ((cname_key = avahi_key_new_cname(key))) {
709 for (c = avahi_hashmap_lookup(e->cache_by_key, cname_key); c; c = c->by_key_next) {
710 callback(e, AVAHI_BROWSER_NEW, AVAHI_LOOKUP_RESULT_WIDE_AREA|AVAHI_LOOKUP_RESULT_CACHED, c->record, userdata);
714 avahi_key_unref(cname_key);
720 int avahi_wide_area_has_servers(AvahiWideAreaLookupEngine *e) {
723 return e->n_dns_servers > 0;