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 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 gboolean avahi_packet_scheduler_post_query(AvahiPacketScheduler *s, AvahiKey *key, gboolean immediately) {
256 avahi_elapse_time(&tv, immediately ? 0 : AVAHI_QUERY_DEFER_MSEC, 0);
258 for (qj = s->query_jobs; qj; qj = qj->jobs_next) {
260 if (avahi_key_equal(qj->key, key)) {
262 glong d = avahi_timeval_diff(&tv, &qj->delivery);
264 /* Duplicate questions suppression */
265 if (d >= 0 && d <= AVAHI_QUERY_HISTORY_MSEC*1000) {
266 g_message("WARNING! DUPLICATE QUERY SUPPRESSION ACTIVE!");
270 query_job_free(s, qj);
276 qj = query_job_new(s, key);
278 qj->time_event = avahi_time_event_queue_add(s->server->time_event_queue, &qj->delivery, query_elapse, qj);
282 static guint8* packet_add_response_job(AvahiPacketScheduler *s, AvahiDnsPacket *p, AvahiResponseJob *rj) {
289 if ((d = avahi_dns_packet_append_record(p, rj->record, rj->flush_cache, 0))) {
294 /* Drop response after some time from history */
295 avahi_elapse_time(&tv, AVAHI_RESPONSE_HISTORY_MSEC, 0);
296 avahi_time_event_queue_update(s->server->time_event_queue, rj->time_event, &tv);
298 g_get_current_time(&rj->delivery);
304 static void send_response_packet(AvahiPacketScheduler *s, AvahiResponseJob *rj) {
310 p = avahi_dns_packet_new_response(s->interface->hardware->mtu, TRUE);
313 /* If a job was specified, put it in the packet. */
316 d = packet_add_response_job(s, p, rj);
321 /* Try to fill up packet with more responses, if available */
322 for (rj = s->response_jobs; rj; rj = rj->jobs_next) {
327 if (!packet_add_response_job(s, p, rj))
333 avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_ANCOUNT, n);
334 avahi_interface_send_packet(s->interface, p);
335 avahi_dns_packet_free(p);
338 static void response_elapse(AvahiTimeEvent *e, gpointer data) {
339 AvahiResponseJob *rj = data;
340 AvahiPacketScheduler *s;
346 /* Lets remove it from the history */
347 response_job_free(s, rj);
351 send_response_packet(s, rj);
354 static AvahiResponseJob* look_for_response(AvahiPacketScheduler *s, AvahiRecord *record) {
355 AvahiResponseJob *rj;
360 for (rj = s->response_jobs; rj; rj = rj->jobs_next)
361 if (avahi_record_equal_no_ttl(rj->record, record))
367 static AvahiResponseJob* response_job_new(AvahiPacketScheduler *s, AvahiRecord *record) {
368 AvahiResponseJob *rj;
373 rj = g_new(AvahiResponseJob, 1);
375 rj->record = avahi_record_ref(record);
377 rj->time_event = NULL;
378 rj->flush_cache = FALSE;
380 AVAHI_LLIST_PREPEND(AvahiResponseJob, jobs, s->response_jobs, rj);
385 gboolean avahi_packet_scheduler_post_response(AvahiPacketScheduler *s, AvahiRecord *record, gboolean flush_cache, gboolean immediately) {
386 AvahiResponseJob *rj;
392 g_assert(!avahi_key_is_pattern(record->key));
394 avahi_elapse_time(&tv, immediately ? 0 : AVAHI_RESPONSE_DEFER_MSEC, immediately ? 0 : AVAHI_RESPONSE_JITTER_MSEC);
396 /* Don't send out duplicates */
398 if ((rj = look_for_response(s, record))) {
401 d = avahi_timeval_diff(&tv, &rj->delivery);
403 /* If there's already a matching packet in our history or in
404 * the schedule, we do nothing. */
405 if (!!record->ttl == !!rj->record->ttl &&
406 d >= 0 && d <= AVAHI_RESPONSE_HISTORY_MSEC*1000) {
407 g_message("WARNING! DUPLICATE RESPONSE SUPPRESSION ACTIVE!");
409 rj->flush_cache = flush_cache;
414 /* Either one was a goodbye packet, but the other was not, so
415 * let's drop the older one. */
416 response_job_free(s, rj);
419 /* g_message("ACCEPTED NEW RESPONSE [%s]", t = avahi_record_to_string(record)); */
422 /* Create a new job and schedule it */
423 rj = response_job_new(s, record);
424 rj->flush_cache = flush_cache;
426 rj->time_event = avahi_time_event_queue_add(s->server->time_event_queue, &rj->delivery, response_elapse, rj);
431 void avahi_packet_scheduler_incoming_query(AvahiPacketScheduler *s, AvahiKey *key) {
438 /* This function is called whenever an incoming query was
439 * receieved. We drop all scheduled queries which match here. The
440 * keyword is "DUPLICATE QUESTION SUPPRESION". */
442 for (qj = s->query_jobs; qj; qj = qj->jobs_next)
443 if (avahi_key_equal(qj->key, key)) {
452 /* No matching job was found. Add the query to the history */
453 qj = query_job_new(s, key);
458 /* Drop the query after some time */
459 avahi_elapse_time(&tv, AVAHI_QUERY_HISTORY_MSEC, 0);
460 qj->time_event = avahi_time_event_queue_add(s->server->time_event_queue, &tv, query_elapse, qj);
462 g_get_current_time(&qj->delivery);
465 void response_job_set_elapse_time(AvahiPacketScheduler *s, AvahiResponseJob *rj, guint msec, guint jitter) {
471 avahi_elapse_time(&tv, msec, jitter);
474 avahi_time_event_queue_update(s->server->time_event_queue, rj->time_event, &tv);
476 rj->time_event = avahi_time_event_queue_add(s->server->time_event_queue, &tv, response_elapse, rj);
479 void avahi_packet_scheduler_incoming_response(AvahiPacketScheduler *s, AvahiRecord *record) {
480 AvahiResponseJob *rj;
485 /* This function is called whenever an incoming response was
486 * receieved. We drop all scheduled responses which match
487 * here. The keyword is "DUPLICATE ANSWER SUPPRESION". */
489 for (rj = s->response_jobs; rj; rj = rj->jobs_next)
490 if (avahi_record_equal_no_ttl(rj->record, record)) {
494 if (!!record->ttl == !!rj->record->ttl) {
495 /* An entry like this is already in our history,
496 * so let's get out of here! */
501 /* Either one was a goodbye packet but other was
502 * none. We remove the history entry, and add a
505 response_job_free(s, rj);
511 if (!!record->ttl == !!rj->record->ttl) {
513 /* The incoming packet matches our scheduled
514 * record, so let's mark that one as done */
520 /* Either one was a goodbye packet but other was
521 * none. We ignore the incoming packet. */
528 /* No matching job was found. Add the query to the history */
529 rj = response_job_new(s, record);
534 /* Drop response after 500ms from history */
535 response_job_set_elapse_time(s, rj, AVAHI_RESPONSE_HISTORY_MSEC, 0);
537 g_get_current_time(&rj->delivery);
540 void avahi_packet_scheduler_flush_responses(AvahiPacketScheduler *s) {
541 AvahiResponseJob *rj;
545 /* Send all scheduled responses, ignoring the scheduled time */
547 for (rj = s->response_jobs; rj; rj = rj->jobs_next)
549 send_response_packet(s, rj);
552 static AvahiProbeJob* probe_job_new(AvahiPacketScheduler *s, AvahiRecord *record) {
558 pj = g_new(AvahiProbeJob, 1);
560 pj->record = avahi_record_ref(record);
561 pj->time_event = NULL;
564 AVAHI_LLIST_PREPEND(AvahiProbeJob, jobs, s->probe_jobs, pj);
569 static guint8* packet_add_probe_query(AvahiPacketScheduler *s, AvahiDnsPacket *p, AvahiProbeJob *pj) {
578 g_assert(!pj->chosen);
580 /* Estimate the size for this record */
582 avahi_key_get_estimate_size(pj->record->key) +
583 avahi_record_get_estimate_size(pj->record);
586 if (size > avahi_dns_packet_space(p))
589 /* Create the probe query */
590 k = avahi_key_new(pj->record->key->name, pj->record->key->class, AVAHI_DNS_TYPE_ANY);
591 ret = avahi_dns_packet_append_key(p, k, FALSE);
594 /* Mark this job for addition to the packet */
597 /* Scan for more jobs whith matching key pattern */
598 for (pj = s->probe_jobs; pj; pj = pj->jobs_next) {
602 /* Does the record match the probe? */
603 if (k->class != pj->record->key->class || !avahi_domain_equal(k->name, pj->record->key->name))
606 /* This job wouldn't fit in */
607 if (avahi_record_get_estimate_size(pj->record) > avahi_dns_packet_space(p))
610 /* Mark this job for addition to the packet */
619 static void probe_elapse(AvahiTimeEvent *e, gpointer data) {
620 AvahiProbeJob *pj = data, *next;
621 AvahiPacketScheduler *s;
628 p = avahi_dns_packet_new_query(s->interface->hardware->mtu);
630 /* Add the import probe */
631 if (!packet_add_probe_query(s, p, pj)) {
632 g_warning("Record too large! ---");
633 avahi_dns_packet_free(p);
639 /* Try to fill up packet with more probes, if available */
640 for (pj = s->probe_jobs; pj; pj = pj->jobs_next) {
645 if (!packet_add_probe_query(s, p, pj))
651 avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_QDCOUNT, n);
655 /* Now add the chosen records to the authorative section */
656 for (pj = s->probe_jobs; pj; pj = next) {
658 next = pj->jobs_next;
663 if (!avahi_dns_packet_append_record(p, pj->record, TRUE, 0)) {
664 g_warning("Bad probe size estimate!");
666 /* Unmark all following jobs */
667 for (; pj; pj = pj->jobs_next)
673 probe_job_free(s, pj);
678 avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_NSCOUNT, n);
681 avahi_interface_send_packet(s->interface, p);
682 avahi_dns_packet_free(p);
685 gboolean avahi_packet_scheduler_post_probe(AvahiPacketScheduler *s, AvahiRecord *record, gboolean immediately) {
691 g_assert(!avahi_key_is_pattern(record->key));
693 avahi_elapse_time(&tv, immediately ? 0 : AVAHI_PROBE_DEFER_MSEC, 0);
695 /* Create a new job and schedule it */
696 pj = probe_job_new(s, record);
698 pj->time_event = avahi_time_event_queue_add(s->server->time_event_queue, &pj->delivery, probe_elapse, pj);