X-Git-Url: http://git.meshlink.io/?a=blobdiff_plain;f=avahi-core%2Fquery-sched.c;fp=avahi-core%2Fquery-sched.c;h=0000000000000000000000000000000000000000;hb=f1de9dcaab953757252d51b4725cbfa36daa10a5;hp=ff833f97b95c2fe3243c5961fecbd79f148a8e8b;hpb=7a5b2f69af7d36d6cd4153142f125fa011784e03;p=catta diff --git a/avahi-core/query-sched.c b/avahi-core/query-sched.c deleted file mode 100644 index ff833f9..0000000 --- a/avahi-core/query-sched.c +++ /dev/null @@ -1,450 +0,0 @@ -/*** - 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 -#endif - -#include - -#include -#include - -#include "query-sched.h" -#include "log.h" - -#define AVAHI_QUERY_HISTORY_MSEC 100 -#define AVAHI_QUERY_DEFER_MSEC 100 - -typedef struct AvahiQueryJob AvahiQueryJob; -typedef struct AvahiKnownAnswer AvahiKnownAnswer; - -struct AvahiQueryJob { - unsigned id; - int n_posted; - - AvahiQueryScheduler *scheduler; - AvahiTimeEvent *time_event; - - int done; - struct timeval delivery; - - AvahiKey *key; - - /* Jobs are stored in a simple linked list. It might turn out in - * the future that this list grows too long and we must switch to - * some other kind of data structure. This needs further - * investigation. I expect the list to be very short (< 20 - * entries) most of the time, but this might be a wrong - * assumption, especially on setups where traffic reflection is - * involved. */ - - AVAHI_LLIST_FIELDS(AvahiQueryJob, jobs); -}; - -struct AvahiKnownAnswer { - AvahiQueryScheduler *scheduler; - AvahiRecord *record; - - AVAHI_LLIST_FIELDS(AvahiKnownAnswer, known_answer); -}; - -struct AvahiQueryScheduler { - AvahiInterface *interface; - AvahiTimeEventQueue *time_event_queue; - - unsigned next_id; - - AVAHI_LLIST_HEAD(AvahiQueryJob, jobs); - AVAHI_LLIST_HEAD(AvahiQueryJob, history); - AVAHI_LLIST_HEAD(AvahiKnownAnswer, known_answers); -}; - -static AvahiQueryJob* job_new(AvahiQueryScheduler *s, AvahiKey *key, int done) { - AvahiQueryJob *qj; - - assert(s); - assert(key); - - if (!(qj = avahi_new(AvahiQueryJob, 1))) { - avahi_log_error(__FILE__": Out of memory"); - return NULL; - } - - qj->scheduler = s; - qj->key = avahi_key_ref(key); - qj->time_event = NULL; - qj->n_posted = 1; - qj->id = s->next_id++; - - if ((qj->done = done)) - AVAHI_LLIST_PREPEND(AvahiQueryJob, jobs, s->history, qj); - else - AVAHI_LLIST_PREPEND(AvahiQueryJob, jobs, s->jobs, qj); - - return qj; -} - -static void job_free(AvahiQueryScheduler *s, AvahiQueryJob *qj) { - assert(s); - assert(qj); - - if (qj->time_event) - avahi_time_event_free(qj->time_event); - - if (qj->done) - AVAHI_LLIST_REMOVE(AvahiQueryJob, jobs, s->history, qj); - else - AVAHI_LLIST_REMOVE(AvahiQueryJob, jobs, s->jobs, qj); - - avahi_key_unref(qj->key); - avahi_free(qj); -} - -static void elapse_callback(AvahiTimeEvent *e, void* data); - -static void job_set_elapse_time(AvahiQueryScheduler *s, AvahiQueryJob *qj, unsigned msec, unsigned jitter) { - struct timeval tv; - - assert(s); - assert(qj); - - avahi_elapse_time(&tv, msec, jitter); - - if (qj->time_event) - avahi_time_event_update(qj->time_event, &tv); - else - qj->time_event = avahi_time_event_new(s->time_event_queue, &tv, elapse_callback, qj); -} - -static void job_mark_done(AvahiQueryScheduler *s, AvahiQueryJob *qj) { - assert(s); - assert(qj); - - assert(!qj->done); - - AVAHI_LLIST_REMOVE(AvahiQueryJob, jobs, s->jobs, qj); - AVAHI_LLIST_PREPEND(AvahiQueryJob, jobs, s->history, qj); - - qj->done = 1; - - job_set_elapse_time(s, qj, AVAHI_QUERY_HISTORY_MSEC, 0); - gettimeofday(&qj->delivery, NULL); -} - -AvahiQueryScheduler *avahi_query_scheduler_new(AvahiInterface *i) { - AvahiQueryScheduler *s; - assert(i); - - if (!(s = avahi_new(AvahiQueryScheduler, 1))) { - avahi_log_error(__FILE__": Out of memory"); - return NULL; /* OOM */ - } - - s->interface = i; - s->time_event_queue = i->monitor->server->time_event_queue; - s->next_id = 0; - - AVAHI_LLIST_HEAD_INIT(AvahiQueryJob, s->jobs); - AVAHI_LLIST_HEAD_INIT(AvahiQueryJob, s->history); - AVAHI_LLIST_HEAD_INIT(AvahiKnownAnswer, s->known_answers); - - return s; -} - -void avahi_query_scheduler_free(AvahiQueryScheduler *s) { - assert(s); - - assert(!s->known_answers); - avahi_query_scheduler_clear(s); - avahi_free(s); -} - -void avahi_query_scheduler_clear(AvahiQueryScheduler *s) { - assert(s); - - while (s->jobs) - job_free(s, s->jobs); - while (s->history) - job_free(s, s->history); -} - -static void* known_answer_walk_callback(AvahiCache *c, AvahiKey *pattern, AvahiCacheEntry *e, void* userdata) { - AvahiQueryScheduler *s = userdata; - AvahiKnownAnswer *ka; - - assert(c); - assert(pattern); - assert(e); - assert(s); - - if (avahi_cache_entry_half_ttl(c, e)) - return NULL; - - if (!(ka = avahi_new0(AvahiKnownAnswer, 1))) { - avahi_log_error(__FILE__": Out of memory"); - return NULL; - } - - ka->scheduler = s; - ka->record = avahi_record_ref(e->record); - - AVAHI_LLIST_PREPEND(AvahiKnownAnswer, known_answer, s->known_answers, ka); - return NULL; -} - -static int packet_add_query_job(AvahiQueryScheduler *s, AvahiDnsPacket *p, AvahiQueryJob *qj) { - assert(s); - assert(p); - assert(qj); - - if (!avahi_dns_packet_append_key(p, qj->key, 0)) - return 0; - - /* Add all matching known answers to the list */ - avahi_cache_walk(s->interface->cache, qj->key, known_answer_walk_callback, s); - - job_mark_done(s, qj); - - return 1; -} - -static void append_known_answers_and_send(AvahiQueryScheduler *s, AvahiDnsPacket *p) { - AvahiKnownAnswer *ka; - unsigned n; - assert(s); - assert(p); - - n = 0; - - while ((ka = s->known_answers)) { - int too_large = 0; - - while (!avahi_dns_packet_append_record(p, ka->record, 0, 0)) { - - if (avahi_dns_packet_is_empty(p)) { - /* The record is too large to fit into one packet, so - there's no point in sending it. Better is letting - the owner of the record send it as a response. This - has the advantage of a cache refresh. */ - - too_large = 1; - break; - } - - avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_FLAGS, avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS) | AVAHI_DNS_FLAG_TC); - avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_ANCOUNT, n); - avahi_interface_send_packet(s->interface, p); - avahi_dns_packet_free(p); - - p = avahi_dns_packet_new_query(s->interface->hardware->mtu); - n = 0; - } - - AVAHI_LLIST_REMOVE(AvahiKnownAnswer, known_answer, s->known_answers, ka); - avahi_record_unref(ka->record); - avahi_free(ka); - - if (!too_large) - n++; - } - - 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) { - AvahiQueryJob *qj = data; - AvahiQueryScheduler *s; - AvahiDnsPacket *p; - unsigned n; - int b; - - assert(qj); - s = qj->scheduler; - - if (qj->done) { - /* Lets remove it from the history */ - job_free(s, qj); - return; - } - - assert(!s->known_answers); - - if (!(p = avahi_dns_packet_new_query(s->interface->hardware->mtu))) - return; /* OOM */ - - b = packet_add_query_job(s, p, qj); - assert(b); /* An query must always fit in */ - n = 1; - - /* Try to fill up packet with more queries, if available */ - while (s->jobs) { - - if (!packet_add_query_job(s, p, s->jobs)) - break; - - n++; - } - - avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_QDCOUNT, n); - - /* Now add known answers */ - append_known_answers_and_send(s, p); -} - -static AvahiQueryJob* find_scheduled_job(AvahiQueryScheduler *s, AvahiKey *key) { - AvahiQueryJob *qj; - - assert(s); - assert(key); - - for (qj = s->jobs; qj; qj = qj->jobs_next) { - assert(!qj->done); - - if (avahi_key_equal(qj->key, key)) - return qj; - } - - return NULL; -} - -static AvahiQueryJob* find_history_job(AvahiQueryScheduler *s, AvahiKey *key) { - AvahiQueryJob *qj; - - assert(s); - assert(key); - - for (qj = s->history; qj; qj = qj->jobs_next) { - assert(qj->done); - - if (avahi_key_equal(qj->key, key)) { - /* Check whether this entry is outdated */ - - if (avahi_age(&qj->delivery) > AVAHI_QUERY_HISTORY_MSEC*1000) { - /* it is outdated, so let's remove it */ - job_free(s, qj); - return NULL; - } - - return qj; - } - } - - return NULL; -} - -int avahi_query_scheduler_post(AvahiQueryScheduler *s, AvahiKey *key, int immediately, unsigned *ret_id) { - struct timeval tv; - AvahiQueryJob *qj; - - assert(s); - assert(key); - - if ((qj = find_history_job(s, key))) - return 0; - - avahi_elapse_time(&tv, immediately ? 0 : AVAHI_QUERY_DEFER_MSEC, 0); - - if ((qj = find_scheduled_job(s, key))) { - /* Duplicate questions suppression */ - - if (avahi_timeval_compare(&tv, &qj->delivery) < 0) { - /* If the new entry should be scheduled earlier, - * update the old entry */ - qj->delivery = tv; - avahi_time_event_update(qj->time_event, &qj->delivery); - } - - qj->n_posted++; - - } else { - - if (!(qj = job_new(s, key, 0))) - return 0; /* OOM */ - - qj->delivery = tv; - qj->time_event = avahi_time_event_new(s->time_event_queue, &qj->delivery, elapse_callback, qj); - } - - if (ret_id) - *ret_id = qj->id; - - return 1; -} - -void avahi_query_scheduler_incoming(AvahiQueryScheduler *s, AvahiKey *key) { - AvahiQueryJob *qj; - - assert(s); - assert(key); - - /* This function is called whenever an incoming query was - * received. We drop scheduled queries that match. The keyword is - * "DUPLICATE QUESTION SUPPRESION". */ - - if ((qj = find_scheduled_job(s, key))) { - job_mark_done(s, qj); - return; - } - - /* Look if there's a history job for this key. If there is, just - * update the elapse time */ - if (!(qj = find_history_job(s, key))) - if (!(qj = job_new(s, key, 1))) - return; /* OOM */ - - gettimeofday(&qj->delivery, NULL); - job_set_elapse_time(s, qj, AVAHI_QUERY_HISTORY_MSEC, 0); -} - -int avahi_query_scheduler_withdraw_by_id(AvahiQueryScheduler *s, unsigned id) { - AvahiQueryJob *qj; - - assert(s); - - /* Very short lived queries can withdraw an already scheduled item - * from the queue using this function, simply by passing the id - * returned by avahi_query_scheduler_post(). */ - - for (qj = s->jobs; qj; qj = qj->jobs_next) { - assert(!qj->done); - - if (qj->id == id) { - /* Entry found */ - - assert(qj->n_posted >= 1); - - if (--qj->n_posted <= 0) { - - /* We withdraw this job only if the calling object was - * the only remaining poster. (Usually this is the - * case since there should exist only one querier per - * key, but there are exceptions, notably reflected - * traffic.) */ - - job_free(s, qj); - return 1; - } - } - } - - return 0; -}