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 #define AVAHI_QUERY_HISTORY_MSEC 100
32 #define AVAHI_QUERY_DEFER_MSEC 100
33 #define AVAHI_RESPONSE_HISTORY_MSEC 700
34 #define AVAHI_RESPONSE_DEFER_MSEC 20
35 #define AVAHI_RESPONSE_JITTER_MSEC 100
36 #define AVAHI_PROBE_DEFER_MSEC 70
38 AvahiPacketScheduler *avahi_packet_scheduler_new(AvahiServer *server, AvahiInterface *i) {
39 AvahiPacketScheduler *s;
44 s = g_new(AvahiPacketScheduler, 1);
48 AVAHI_LLIST_HEAD_INIT(AvahiQueryJob, s->query_jobs);
49 AVAHI_LLIST_HEAD_INIT(AvahiResponseJob, s->response_jobs);
50 AVAHI_LLIST_HEAD_INIT(AvahiKnownAnswer, s->known_answers);
51 AVAHI_LLIST_HEAD_INIT(AvahiProbeJob, s->probe_jobs);
56 static void query_job_free(AvahiPacketScheduler *s, AvahiQueryJob *qj) {
60 avahi_time_event_queue_remove(qj->scheduler->server->time_event_queue, qj->time_event);
62 AVAHI_LLIST_REMOVE(AvahiQueryJob, jobs, s->query_jobs, qj);
64 avahi_key_unref(qj->key);
68 static void response_job_free(AvahiPacketScheduler *s, AvahiResponseJob *rj) {
72 avahi_time_event_queue_remove(rj->scheduler->server->time_event_queue, rj->time_event);
74 AVAHI_LLIST_REMOVE(AvahiResponseJob, jobs, s->response_jobs, rj);
76 avahi_record_unref(rj->record);
80 static void probe_job_free(AvahiPacketScheduler *s, AvahiProbeJob *pj) {
84 avahi_time_event_queue_remove(pj->scheduler->server->time_event_queue, pj->time_event);
86 AVAHI_LLIST_REMOVE(AvahiProbeJob, jobs, s->probe_jobs, pj);
88 avahi_record_unref(pj->record);
92 void avahi_packet_scheduler_free(AvahiPacketScheduler *s) {
99 g_assert(!s->known_answers);
101 while ((qj = s->query_jobs))
102 query_job_free(s, qj);
103 while ((rj = s->response_jobs))
104 response_job_free(s, rj);
105 while ((pj = s->probe_jobs))
106 probe_job_free(s, pj);
111 static gpointer known_answer_walk_callback(AvahiCache *c, AvahiKey *pattern, AvahiCacheEntry *e, gpointer userdata) {
112 AvahiPacketScheduler *s = userdata;
113 AvahiKnownAnswer *ka;
120 if (avahi_cache_entry_half_ttl(c, e))
123 ka = g_new0(AvahiKnownAnswer, 1);
125 ka->record = avahi_record_ref(e->record);
127 AVAHI_LLIST_PREPEND(AvahiKnownAnswer, known_answer, s->known_answers, ka);
131 static guint8* packet_add_query_job(AvahiPacketScheduler *s, AvahiDnsPacket *p, AvahiQueryJob *qj) {
138 if ((d = avahi_dns_packet_append_key(p, qj->key, FALSE))) {
143 /* Drop query after some time from history */
144 avahi_elapse_time(&tv, AVAHI_QUERY_HISTORY_MSEC, 0);
145 avahi_time_event_queue_update(s->server->time_event_queue, qj->time_event, &tv);
147 g_get_current_time(&qj->delivery);
149 /* Add all matching known answers to the list */
150 avahi_cache_walk(s->interface->cache, qj->key, known_answer_walk_callback, s);
156 static void append_known_answers_and_send(AvahiPacketScheduler *s, AvahiDnsPacket *p) {
157 AvahiKnownAnswer *ka;
164 while ((ka = s->known_answers)) {
166 while (!avahi_dns_packet_append_record(p, ka->record, FALSE, 0)) {
168 g_assert(!avahi_dns_packet_is_empty(p));
170 avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_FLAGS, avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS) | AVAHI_DNS_FLAG_TC);
171 avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_ANCOUNT, n);
172 avahi_interface_send_packet(s->interface, p);
173 avahi_dns_packet_free(p);
175 p = avahi_dns_packet_new_query(s->interface->hardware->mtu);
179 AVAHI_LLIST_REMOVE(AvahiKnownAnswer, known_answer, s->known_answers, ka);
180 avahi_record_unref(ka->record);
186 avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_ANCOUNT, n);
187 avahi_interface_send_packet(s->interface, p);
188 avahi_dns_packet_free(p);
191 static void query_elapse(AvahiTimeEvent *e, gpointer data) {
192 AvahiQueryJob *qj = data;
193 AvahiPacketScheduler *s;
202 /* Lets remove it from the history */
203 query_job_free(s, qj);
207 g_assert(!s->known_answers);
209 p = avahi_dns_packet_new_query(s->interface->hardware->mtu);
210 d = packet_add_query_job(s, p, qj);
214 /* Try to fill up packet with more queries, if available */
215 for (qj = s->query_jobs; qj; qj = qj->jobs_next) {
220 if (!packet_add_query_job(s, p, qj))
226 avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_QDCOUNT, n);
228 /* Now add known answers */
229 append_known_answers_and_send(s, p);
232 static AvahiQueryJob* query_job_new(AvahiPacketScheduler *s, AvahiKey *key) {
238 qj = g_new(AvahiQueryJob, 1);
240 qj->key = avahi_key_ref(key);
242 qj->time_event = NULL;
244 AVAHI_LLIST_PREPEND(AvahiQueryJob, jobs, s->query_jobs, qj);
249 static AvahiQueryJob* look_for_query(AvahiPacketScheduler *s, AvahiKey *key) {
255 for (qj = s->query_jobs; qj; qj = qj->jobs_next)
256 if (avahi_key_equal(qj->key, key))
262 gboolean avahi_packet_scheduler_post_query(AvahiPacketScheduler *s, AvahiKey *key, gboolean immediately) {
269 avahi_elapse_time(&tv, immediately ? 0 : AVAHI_QUERY_DEFER_MSEC, 0);
271 if ((qj = look_for_query(s, key))) {
272 glong d = avahi_timeval_diff(&tv, &qj->delivery);
274 /* Duplicate questions suppression */
275 if (!qj->done || d <= AVAHI_QUERY_HISTORY_MSEC*1000) {
276 g_message("WARNING! DUPLICATE QUERY SUPPRESSION ACTIVE!");
278 if (!qj->done && d < 0) {
279 /* If the new entry should be scheduled earlier,
280 * update the old entry */
282 avahi_time_event_queue_update(s->server->time_event_queue, qj->time_event, &qj->delivery);
287 query_job_free(s, qj);
290 qj = query_job_new(s, key);
292 qj->time_event = avahi_time_event_queue_add(s->server->time_event_queue, &qj->delivery, query_elapse, qj);
297 void avahi_packet_scheduler_incoming_query(AvahiPacketScheduler *s, AvahiKey *key) {
304 /* This function is called whenever an incoming query was
305 * receieved. We mark all matching queries that match as done. The
306 * keyword is "DUPLICATE QUESTION SUPPRESION". */
308 if (!(qj = look_for_query(s, key)))
309 qj = query_job_new(s, key);
313 /* Drop the query after some time */
314 avahi_elapse_time(&tv, AVAHI_QUERY_HISTORY_MSEC, 0);
317 avahi_time_event_queue_update(s->server->time_event_queue, qj->time_event, &tv);
319 qj->time_event = avahi_time_event_queue_add(s->server->time_event_queue, &tv, query_elapse, qj);
321 g_get_current_time(&qj->delivery);
324 static guint8* packet_add_response_job(AvahiPacketScheduler *s, AvahiDnsPacket *p, AvahiResponseJob *rj) {
331 if ((d = avahi_dns_packet_append_record(p, rj->record, rj->flush_cache, 0))) {
336 /* Drop response after some time from history */
337 avahi_elapse_time(&tv, AVAHI_RESPONSE_HISTORY_MSEC, 0);
338 avahi_time_event_queue_update(s->server->time_event_queue, rj->time_event, &tv);
340 g_get_current_time(&rj->delivery);
346 static void send_response_packet(AvahiPacketScheduler *s, AvahiResponseJob *rj) {
352 p = avahi_dns_packet_new_response(s->interface->hardware->mtu, TRUE);
355 /* If a job was specified, put it in the packet. */
358 d = packet_add_response_job(s, p, rj);
363 /* Try to fill up packet with more responses, if available */
364 for (rj = s->response_jobs; rj; rj = rj->jobs_next) {
369 if (!packet_add_response_job(s, p, rj))
375 avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_ANCOUNT, n);
376 avahi_interface_send_packet(s->interface, p);
377 avahi_dns_packet_free(p);
380 static void response_elapse(AvahiTimeEvent *e, gpointer data) {
381 AvahiResponseJob *rj = data;
382 AvahiPacketScheduler *s;
388 /* Lets remove it from the history */
389 response_job_free(s, rj);
393 send_response_packet(s, rj);
396 static AvahiResponseJob* look_for_response(AvahiPacketScheduler *s, AvahiRecord *record) {
397 AvahiResponseJob *rj;
402 for (rj = s->response_jobs; rj; rj = rj->jobs_next)
403 if (avahi_record_equal_no_ttl(rj->record, record))
409 static AvahiResponseJob* response_job_new(AvahiPacketScheduler *s, AvahiRecord *record) {
410 AvahiResponseJob *rj;
415 rj = g_new(AvahiResponseJob, 1);
417 rj->record = avahi_record_ref(record);
419 rj->time_event = NULL;
420 rj->flush_cache = FALSE;
421 rj->querier_valid = FALSE;
423 AVAHI_LLIST_PREPEND(AvahiResponseJob, jobs, s->response_jobs, rj);
428 gboolean avahi_packet_scheduler_post_response(AvahiPacketScheduler *s, AvahiRecord *record, gboolean flush_cache, gboolean immediately, const AvahiAddress *querier) {
429 AvahiResponseJob *rj;
435 g_assert(!avahi_key_is_pattern(record->key));
437 avahi_elapse_time(&tv, immediately ? 0 : AVAHI_RESPONSE_DEFER_MSEC, immediately ? 0 : AVAHI_RESPONSE_JITTER_MSEC);
439 /* Don't send out duplicates */
441 if ((rj = look_for_response(s, record))) {
443 glong d = avahi_timeval_diff(&tv, &rj->delivery);
445 /* If there's already a matching packet in our history or in
446 * the schedule, we do nothing. */
448 if ((!!record->ttl == !!rj->record->ttl) &&
449 (rj->flush_cache || !flush_cache) &&
450 ((!rj->done && d >= 0) || (rj->done && d <= AVAHI_RESPONSE_HISTORY_MSEC*1000))) {
452 g_message("Duplicate suppresion active.");
456 /* If the old job was not yet done but scheduled earlier than
457 * our new one, we chedule our new job at the same time. */
458 if (!rj->done && d > 0)
461 /* If the old job had the flush_cache bit enabled, we must
462 enable it on our new one, too */
463 if (!rj->done && rj->flush_cache)
466 /* For known answer suppresion we have record for which host this data was intended */
467 if (querier && !rj->done && (!rj->querier_valid || avahi_address_cmp(&rj->querier, querier) != 0))
470 /* The old job wasn't good enough, so let's drop it */
471 response_job_free(s, rj);
474 /* Create a new job and schedule it */
475 rj = response_job_new(s, record);
476 rj->flush_cache = flush_cache;
478 rj->time_event = avahi_time_event_queue_add(s->server->time_event_queue, &rj->delivery, response_elapse, rj);
480 if ((rj->querier_valid = !!querier))
481 rj->querier = *querier;
486 void response_job_set_elapse_time(AvahiPacketScheduler *s, AvahiResponseJob *rj, guint msec, guint jitter) {
492 avahi_elapse_time(&tv, msec, jitter);
495 avahi_time_event_queue_update(s->server->time_event_queue, rj->time_event, &tv);
497 rj->time_event = avahi_time_event_queue_add(s->server->time_event_queue, &tv, response_elapse, rj);
500 void avahi_packet_scheduler_incoming_response(AvahiPacketScheduler *s, AvahiRecord *record, gboolean flush_cache) {
501 AvahiResponseJob *rj = NULL;
506 /* This function is called whenever an incoming response was
507 * receieved. We drop all scheduled responses which match
508 * here. The keyword is "DUPLICATE ANSWER SUPPRESION". */
510 if ((rj = look_for_response(s, record))) {
514 if (rj->flush_cache && !flush_cache)
515 /* The incoming response didn't have flush_cache
516 * set, but our scheduled has => we still have to
517 * send our response */
521 if (!!record->ttl != !!rj->record->ttl) {
522 /* Either one was a goodbye packet but other was
523 * none => we still have to send our response */
528 /* The two responses match, so let's mark the history
529 * entry as done or update it */
532 /* No matching job was found. Add the query to the history */
534 rj = response_job_new(s, record);
536 avahi_record_unref(rj->record);
537 rj->record = avahi_record_ref(record);
541 rj->flush_cache = rj->flush_cache || flush_cache;
543 /* Drop response after 500ms from history */
544 response_job_set_elapse_time(s, rj, AVAHI_RESPONSE_HISTORY_MSEC, 0);
546 g_get_current_time(&rj->delivery);
550 void avahi_packet_scheduler_incoming_known_answer(AvahiPacketScheduler *s, AvahiRecord *record, const AvahiAddress *querier) {
551 AvahiResponseJob *rj;
557 /* Check whether a matching job has been scheduled */
558 if (!(rj = look_for_response(s, record)) || rj->done)
561 /* Chech whether another querier demanded the original job */
562 if (!rj->querier_valid || avahi_address_cmp(&rj->querier, querier) != 0)
565 /* Check whether one of them is a goodbye packet, while the other is not */
566 if (!!record->ttl != !!rj->record->ttl)
569 /* Check whether the known answer has a good TTL */
570 if (record->ttl <= rj->record->ttl/2)
573 g_message("Known answer suppression active!");
574 response_job_free(s, rj);
577 void avahi_packet_scheduler_flush_responses(AvahiPacketScheduler *s) {
578 AvahiResponseJob *rj;
582 /* Send all scheduled responses, ignoring the scheduled time */
584 for (rj = s->response_jobs; rj; rj = rj->jobs_next)
586 send_response_packet(s, rj);
589 static AvahiProbeJob* probe_job_new(AvahiPacketScheduler *s, AvahiRecord *record) {
595 pj = g_new(AvahiProbeJob, 1);
597 pj->record = avahi_record_ref(record);
598 pj->time_event = NULL;
601 AVAHI_LLIST_PREPEND(AvahiProbeJob, jobs, s->probe_jobs, pj);
606 static guint8* packet_add_probe_query(AvahiPacketScheduler *s, AvahiDnsPacket *p, AvahiProbeJob *pj) {
615 g_assert(!pj->chosen);
617 /* Estimate the size for this record */
619 avahi_key_get_estimate_size(pj->record->key) +
620 avahi_record_get_estimate_size(pj->record);
623 if (size > avahi_dns_packet_space(p))
626 /* Create the probe query */
627 k = avahi_key_new(pj->record->key->name, pj->record->key->class, AVAHI_DNS_TYPE_ANY);
628 ret = avahi_dns_packet_append_key(p, k, FALSE);
631 /* Mark this job for addition to the packet */
634 /* Scan for more jobs whith matching key pattern */
635 for (pj = s->probe_jobs; pj; pj = pj->jobs_next) {
639 /* Does the record match the probe? */
640 if (k->class != pj->record->key->class || !avahi_domain_equal(k->name, pj->record->key->name))
643 /* This job wouldn't fit in */
644 if (avahi_record_get_estimate_size(pj->record) > avahi_dns_packet_space(p))
647 /* Mark this job for addition to the packet */
656 static void probe_elapse(AvahiTimeEvent *e, gpointer data) {
657 AvahiProbeJob *pj = data, *next;
658 AvahiPacketScheduler *s;
665 p = avahi_dns_packet_new_query(s->interface->hardware->mtu);
667 /* Add the import probe */
668 if (!packet_add_probe_query(s, p, pj)) {
669 g_warning("Record too large! ---");
670 avahi_dns_packet_free(p);
676 /* Try to fill up packet with more probes, if available */
677 for (pj = s->probe_jobs; pj; pj = pj->jobs_next) {
682 if (!packet_add_probe_query(s, p, pj))
688 avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_QDCOUNT, n);
692 /* Now add the chosen records to the authorative section */
693 for (pj = s->probe_jobs; pj; pj = next) {
695 next = pj->jobs_next;
700 if (!avahi_dns_packet_append_record(p, pj->record, FALSE, 0)) {
701 g_warning("Bad probe size estimate!");
703 /* Unmark all following jobs */
704 for (; pj; pj = pj->jobs_next)
710 probe_job_free(s, pj);
715 avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_NSCOUNT, n);
718 avahi_interface_send_packet(s->interface, p);
719 avahi_dns_packet_free(p);
722 gboolean avahi_packet_scheduler_post_probe(AvahiPacketScheduler *s, AvahiRecord *record, gboolean immediately) {
728 g_assert(!avahi_key_is_pattern(record->key));
730 avahi_elapse_time(&tv, immediately ? 0 : AVAHI_PROBE_DEFER_MSEC, 0);
732 /* Create a new job and schedule it */
733 pj = probe_job_new(s, record);
735 pj->time_event = avahi_time_event_queue_add(s->server->time_event_queue, &pj->delivery, probe_elapse, pj);