+++ /dev/null
-/***
- This file is part of avahi.
-
- avahi is free software; you can redistribute it and/or modify it
- under the terms of the GNU Lesser General Public License as
- published by the Free Software Foundation; either version 2.1 of the
- License, or (at your option) any later version.
-
- avahi is distributed in the hope that it will be useful, but WITHOUT
- ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
- Public License for more details.
-
- You should have received a copy of the GNU Lesser General Public
- License along with avahi; if not, write to the Free Software
- Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
- USA.
-***/
-
-#ifdef HAVE_CONFIG_H
-#include <config.h>
-#endif
-
-#include <stdlib.h>
-
-#include <avahi-common/timeval.h>
-#include <avahi-common/malloc.h>
-
-#include "response-sched.h"
-#include "log.h"
-#include "rr-util.h"
-
-/* Local packets are supressed this long after sending them */
-#define AVAHI_RESPONSE_HISTORY_MSEC 500
-
-/* Local packets are deferred this long before sending them */
-#define AVAHI_RESPONSE_DEFER_MSEC 20
-
-/* Additional jitter for deferred packets */
-#define AVAHI_RESPONSE_JITTER_MSEC 100
-
-/* Remote packets can suppress local traffic as long as this value */
-#define AVAHI_RESPONSE_SUPPRESS_MSEC 700
-
-typedef struct AvahiResponseJob AvahiResponseJob;
-
-typedef enum {
- AVAHI_SCHEDULED,
- AVAHI_DONE,
- AVAHI_SUPPRESSED
-} AvahiResponseJobState;
-
-struct AvahiResponseJob {
- AvahiResponseScheduler *scheduler;
- AvahiTimeEvent *time_event;
-
- AvahiResponseJobState state;
- struct timeval delivery;
-
- AvahiRecord *record;
- int flush_cache;
- AvahiAddress querier;
- int querier_valid;
-
- AVAHI_LLIST_FIELDS(AvahiResponseJob, jobs);
-};
-
-struct AvahiResponseScheduler {
- AvahiInterface *interface;
- AvahiTimeEventQueue *time_event_queue;
-
- AVAHI_LLIST_HEAD(AvahiResponseJob, jobs);
- AVAHI_LLIST_HEAD(AvahiResponseJob, history);
- AVAHI_LLIST_HEAD(AvahiResponseJob, suppressed);
-};
-
-static AvahiResponseJob* job_new(AvahiResponseScheduler *s, AvahiRecord *record, AvahiResponseJobState state) {
- AvahiResponseJob *rj;
-
- assert(s);
- assert(record);
-
- if (!(rj = avahi_new(AvahiResponseJob, 1))) {
- avahi_log_error(__FILE__": Out of memory");
- return NULL;
- }
-
- rj->scheduler = s;
- rj->record = avahi_record_ref(record);
- rj->time_event = NULL;
- rj->flush_cache = 0;
- rj->querier_valid = 0;
-
- if ((rj->state = state) == AVAHI_SCHEDULED)
- AVAHI_LLIST_PREPEND(AvahiResponseJob, jobs, s->jobs, rj);
- else if (rj->state == AVAHI_DONE)
- AVAHI_LLIST_PREPEND(AvahiResponseJob, jobs, s->history, rj);
- else /* rj->state == AVAHI_SUPPRESSED */
- AVAHI_LLIST_PREPEND(AvahiResponseJob, jobs, s->suppressed, rj);
-
- return rj;
-}
-
-static void job_free(AvahiResponseScheduler *s, AvahiResponseJob *rj) {
- assert(s);
- assert(rj);
-
- if (rj->time_event)
- avahi_time_event_free(rj->time_event);
-
- if (rj->state == AVAHI_SCHEDULED)
- AVAHI_LLIST_REMOVE(AvahiResponseJob, jobs, s->jobs, rj);
- else if (rj->state == AVAHI_DONE)
- AVAHI_LLIST_REMOVE(AvahiResponseJob, jobs, s->history, rj);
- else /* rj->state == AVAHI_SUPPRESSED */
- AVAHI_LLIST_REMOVE(AvahiResponseJob, jobs, s->suppressed, rj);
-
- avahi_record_unref(rj->record);
- avahi_free(rj);
-}
-
-static void elapse_callback(AvahiTimeEvent *e, void* data);
-
-static void job_set_elapse_time(AvahiResponseScheduler *s, AvahiResponseJob *rj, unsigned msec, unsigned jitter) {
- struct timeval tv;
-
- assert(s);
- assert(rj);
-
- avahi_elapse_time(&tv, msec, jitter);
-
- if (rj->time_event)
- avahi_time_event_update(rj->time_event, &tv);
- else
- rj->time_event = avahi_time_event_new(s->time_event_queue, &tv, elapse_callback, rj);
-}
-
-static void job_mark_done(AvahiResponseScheduler *s, AvahiResponseJob *rj) {
- assert(s);
- assert(rj);
-
- assert(rj->state == AVAHI_SCHEDULED);
-
- AVAHI_LLIST_REMOVE(AvahiResponseJob, jobs, s->jobs, rj);
- AVAHI_LLIST_PREPEND(AvahiResponseJob, jobs, s->history, rj);
-
- rj->state = AVAHI_DONE;
-
- job_set_elapse_time(s, rj, AVAHI_RESPONSE_HISTORY_MSEC, 0);
-
- gettimeofday(&rj->delivery, NULL);
-}
-
-AvahiResponseScheduler *avahi_response_scheduler_new(AvahiInterface *i) {
- AvahiResponseScheduler *s;
- assert(i);
-
- if (!(s = avahi_new(AvahiResponseScheduler, 1))) {
- avahi_log_error(__FILE__": Out of memory");
- return NULL;
- }
-
- s->interface = i;
- s->time_event_queue = i->monitor->server->time_event_queue;
-
- AVAHI_LLIST_HEAD_INIT(AvahiResponseJob, s->jobs);
- AVAHI_LLIST_HEAD_INIT(AvahiResponseJob, s->history);
- AVAHI_LLIST_HEAD_INIT(AvahiResponseJob, s->suppressed);
-
- return s;
-}
-
-void avahi_response_scheduler_free(AvahiResponseScheduler *s) {
- assert(s);
-
- avahi_response_scheduler_clear(s);
- avahi_free(s);
-}
-
-void avahi_response_scheduler_clear(AvahiResponseScheduler *s) {
- assert(s);
-
- while (s->jobs)
- job_free(s, s->jobs);
- while (s->history)
- job_free(s, s->history);
- while (s->suppressed)
- job_free(s, s->suppressed);
-}
-
-static void enumerate_aux_records_callback(AVAHI_GCC_UNUSED AvahiServer *s, AvahiRecord *r, int flush_cache, void* userdata) {
- AvahiResponseJob *rj = userdata;
-
- assert(r);
- assert(rj);
-
- avahi_response_scheduler_post(rj->scheduler, r, flush_cache, rj->querier_valid ? &rj->querier : NULL, 0);
-}
-
-static int packet_add_response_job(AvahiResponseScheduler *s, AvahiDnsPacket *p, AvahiResponseJob *rj) {
- assert(s);
- assert(p);
- assert(rj);
-
- /* Try to add this record to the packet */
- if (!avahi_dns_packet_append_record(p, rj->record, rj->flush_cache, 0))
- return 0;
-
- /* Ok, this record will definitely be sent, so schedule the
- * auxilliary packets, too */
- avahi_server_enumerate_aux_records(s->interface->monitor->server, s->interface, rj->record, enumerate_aux_records_callback, rj);
- job_mark_done(s, rj);
-
- return 1;
-}
-
-static void send_response_packet(AvahiResponseScheduler *s, AvahiResponseJob *rj) {
- AvahiDnsPacket *p;
- unsigned n;
-
- assert(s);
- assert(rj);
-
- if (!(p = avahi_dns_packet_new_response(s->interface->hardware->mtu, 1)))
- return; /* OOM */
- n = 1;
-
- /* Put it in the packet. */
- if (packet_add_response_job(s, p, rj)) {
-
- /* Try to fill up packet with more responses, if available */
- while (s->jobs) {
-
- if (!packet_add_response_job(s, p, s->jobs))
- break;
-
- n++;
- }
-
- } else {
- size_t size;
-
- avahi_dns_packet_free(p);
-
- /* OK, the packet was too small, so create one that fits */
- size = avahi_record_get_estimate_size(rj->record) + AVAHI_DNS_PACKET_HEADER_SIZE;
-
- if (!(p = avahi_dns_packet_new_response(size + AVAHI_DNS_PACKET_EXTRA_SIZE, 1)))
- return; /* OOM */
-
- if (!packet_add_response_job(s, p, rj)) {
- avahi_dns_packet_free(p);
-
- avahi_log_warn("Record too large, cannot send");
- job_mark_done(s, rj);
- return;
- }
- }
-
- avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_ANCOUNT, n);
- avahi_interface_send_packet(s->interface, p);
- avahi_dns_packet_free(p);
-}
-
-static void elapse_callback(AVAHI_GCC_UNUSED AvahiTimeEvent *e, void* data) {
- AvahiResponseJob *rj = data;
-
- assert(rj);
-
- if (rj->state == AVAHI_DONE || rj->state == AVAHI_SUPPRESSED)
- job_free(rj->scheduler, rj); /* Lets drop this entry */
- else
- send_response_packet(rj->scheduler, rj);
-}
-
-static AvahiResponseJob* find_scheduled_job(AvahiResponseScheduler *s, AvahiRecord *record) {
- AvahiResponseJob *rj;
-
- assert(s);
- assert(record);
-
- for (rj = s->jobs; rj; rj = rj->jobs_next) {
- assert(rj->state == AVAHI_SCHEDULED);
-
- if (avahi_record_equal_no_ttl(rj->record, record))
- return rj;
- }
-
- return NULL;
-}
-
-static AvahiResponseJob* find_history_job(AvahiResponseScheduler *s, AvahiRecord *record) {
- AvahiResponseJob *rj;
-
- assert(s);
- assert(record);
-
- for (rj = s->history; rj; rj = rj->jobs_next) {
- assert(rj->state == AVAHI_DONE);
-
- if (avahi_record_equal_no_ttl(rj->record, record)) {
- /* Check whether this entry is outdated */
-
-/* avahi_log_debug("history age: %u", (unsigned) (avahi_age(&rj->delivery)/1000)); */
-
- if (avahi_age(&rj->delivery)/1000 > AVAHI_RESPONSE_HISTORY_MSEC) {
- /* it is outdated, so let's remove it */
- job_free(s, rj);
- return NULL;
- }
-
- return rj;
- }
- }
-
- return NULL;
-}
-
-static AvahiResponseJob* find_suppressed_job(AvahiResponseScheduler *s, AvahiRecord *record, const AvahiAddress *querier) {
- AvahiResponseJob *rj;
-
- assert(s);
- assert(record);
- assert(querier);
-
- for (rj = s->suppressed; rj; rj = rj->jobs_next) {
- assert(rj->state == AVAHI_SUPPRESSED);
- assert(rj->querier_valid);
-
- if (avahi_record_equal_no_ttl(rj->record, record) &&
- avahi_address_cmp(&rj->querier, querier) == 0) {
- /* Check whether this entry is outdated */
-
- if (avahi_age(&rj->delivery) > AVAHI_RESPONSE_SUPPRESS_MSEC*1000) {
- /* it is outdated, so let's remove it */
- job_free(s, rj);
- return NULL;
- }
-
- return rj;
- }
- }
-
- return NULL;
-}
-
-int avahi_response_scheduler_post(AvahiResponseScheduler *s, AvahiRecord *record, int flush_cache, const AvahiAddress *querier, int immediately) {
- AvahiResponseJob *rj;
- struct timeval tv;
-/* char *t; */
-
- assert(s);
- assert(record);
-
- assert(!avahi_key_is_pattern(record->key));
-
-/* t = avahi_record_to_string(record); */
-/* avahi_log_debug("post %i %s", immediately, t); */
-/* avahi_free(t); */
-
- /* Check whether this response is suppressed */
- if (querier &&
- (rj = find_suppressed_job(s, record, querier)) &&
- avahi_record_is_goodbye(record) == avahi_record_is_goodbye(rj->record) &&
- rj->record->ttl >= record->ttl/2) {
-
-/* avahi_log_debug("Response suppressed by known answer suppression."); */
- return 0;
- }
-
- /* Check if we already sent this response recently */
- if ((rj = find_history_job(s, record))) {
-
- if (avahi_record_is_goodbye(record) == avahi_record_is_goodbye(rj->record) &&
- rj->record->ttl >= record->ttl/2 &&
- (rj->flush_cache || !flush_cache)) {
-/* avahi_log_debug("Response suppressed by local duplicate suppression (history)"); */
- return 0;
- }
-
- /* Outdated ... */
- job_free(s, rj);
- }
-
- avahi_elapse_time(&tv, immediately ? 0 : AVAHI_RESPONSE_DEFER_MSEC, immediately ? 0 : AVAHI_RESPONSE_JITTER_MSEC);
-
- if ((rj = find_scheduled_job(s, record))) {
-/* avahi_log_debug("Response suppressed by local duplicate suppression (scheduled)"); */
-
- /* Update a little ... */
-
- /* Update the time if the new is prior to the old */
- if (avahi_timeval_compare(&tv, &rj->delivery) < 0) {
- rj->delivery = tv;
- avahi_time_event_update(rj->time_event, &rj->delivery);
- }
-
- /* Update the flush cache bit */
- if (flush_cache)
- rj->flush_cache = 1;
-
- /* Update the querier field */
- if (!querier || (rj->querier_valid && avahi_address_cmp(querier, &rj->querier) != 0))
- rj->querier_valid = 0;
-
- /* Update record data (just for the TTL) */
- avahi_record_unref(rj->record);
- rj->record = avahi_record_ref(record);
-
- return 1;
- } else {
-/* avahi_log_debug("Accepted new response job."); */
-
- /* Create a new job and schedule it */
- if (!(rj = job_new(s, record, AVAHI_SCHEDULED)))
- return 0; /* OOM */
-
- rj->delivery = tv;
- rj->time_event = avahi_time_event_new(s->time_event_queue, &rj->delivery, elapse_callback, rj);
- rj->flush_cache = flush_cache;
-
- if ((rj->querier_valid = !!querier))
- rj->querier = *querier;
-
- return 1;
- }
-}
-
-void avahi_response_scheduler_incoming(AvahiResponseScheduler *s, AvahiRecord *record, int flush_cache) {
- AvahiResponseJob *rj;
- assert(s);
-
- /* This function is called whenever an incoming response was
- * receieved. We drop scheduled responses which match here. The
- * keyword is "DUPLICATE ANSWER SUPPRESION". */
-
- if ((rj = find_scheduled_job(s, record))) {
-
- if ((!rj->flush_cache || flush_cache) && /* flush cache bit was set correctly */
- avahi_record_is_goodbye(record) == avahi_record_is_goodbye(rj->record) && /* both goodbye packets, or both not */
- record->ttl >= rj->record->ttl/2) { /* sensible TTL */
-
- /* A matching entry was found, so let's mark it done */
-/* avahi_log_debug("Response suppressed by distributed duplicate suppression"); */
- job_mark_done(s, rj);
- }
-
- return;
- }
-
- if ((rj = find_history_job(s, record))) {
- /* Found a history job, let's update it */
- avahi_record_unref(rj->record);
- rj->record = avahi_record_ref(record);
- } else
- /* Found no existing history job, so let's create a new one */
- if (!(rj = job_new(s, record, AVAHI_DONE)))
- return; /* OOM */
-
- rj->flush_cache = flush_cache;
- rj->querier_valid = 0;
-
- gettimeofday(&rj->delivery, NULL);
- job_set_elapse_time(s, rj, AVAHI_RESPONSE_HISTORY_MSEC, 0);
-}
-
-void avahi_response_scheduler_suppress(AvahiResponseScheduler *s, AvahiRecord *record, const AvahiAddress *querier) {
- AvahiResponseJob *rj;
-
- assert(s);
- assert(record);
- assert(querier);
-
- if ((rj = find_scheduled_job(s, record))) {
-
- if (rj->querier_valid && avahi_address_cmp(querier, &rj->querier) == 0 && /* same originator */
- avahi_record_is_goodbye(record) == avahi_record_is_goodbye(rj->record) && /* both goodbye packets, or both not */
- record->ttl >= rj->record->ttl/2) { /* sensible TTL */
-
- /* A matching entry was found, so let's drop it */
-/* avahi_log_debug("Known answer suppression active!"); */
- job_free(s, rj);
- }
- }
-
- if ((rj = find_suppressed_job(s, record, querier))) {
-
- /* Let's update the old entry */
- avahi_record_unref(rj->record);
- rj->record = avahi_record_ref(record);
-
- } else {
-
- /* Create a new entry */
- if (!(rj = job_new(s, record, AVAHI_SUPPRESSED)))
- return; /* OOM */
- rj->querier_valid = 1;
- rj->querier = *querier;
- }
-
- gettimeofday(&rj->delivery, NULL);
- job_set_elapse_time(s, rj, AVAHI_RESPONSE_SUPPRESS_MSEC, 0);
-}
-
-void avahi_response_scheduler_force(AvahiResponseScheduler *s) {
- assert(s);
-
- /* Send all scheduled responses immediately */
- while (s->jobs)
- send_response_packet(s, s->jobs);
-}
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