X-Git-Url: http://git.meshlink.io/?a=blobdiff_plain;f=avahi-core%2Fquery-sched.c;h=ff833f97b95c2fe3243c5961fecbd79f148a8e8b;hb=147cdce70b22ae7cee9fb4fe123db40952f31c9e;hp=129b15e4c653ebd7d32b2be465a12c3db1d19da8;hpb=e63a65b3955b173a3e8d6b78c6377a518a9922d6;p=catta

diff --git a/avahi-core/query-sched.c b/avahi-core/query-sched.c
index 129b15e..ff833f9 100644
--- a/avahi-core/query-sched.c
+++ b/avahi-core/query-sched.c
@@ -1,18 +1,16 @@
-/* $Id$ */
-
 /***
   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
@@ -23,8 +21,13 @@
 #include <config.h>
 #endif
 
+#include <stdlib.h>
+
+#include <avahi-common/timeval.h>
+#include <avahi-common/malloc.h>
+
 #include "query-sched.h"
-#include "util.h"
+#include "log.h"
 
 #define AVAHI_QUERY_HISTORY_MSEC 100
 #define AVAHI_QUERY_DEFER_MSEC 100
@@ -33,14 +36,25 @@ typedef struct AvahiQueryJob AvahiQueryJob;
 typedef struct AvahiKnownAnswer AvahiKnownAnswer;
 
 struct AvahiQueryJob {
+    unsigned id;
+    int n_posted;
+
     AvahiQueryScheduler *scheduler;
     AvahiTimeEvent *time_event;
-    
-    gboolean done;
+
+    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);
 };
 
@@ -55,23 +69,31 @@ 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, gboolean done) {
+static AvahiQueryJob* job_new(AvahiQueryScheduler *s, AvahiKey *key, int done) {
     AvahiQueryJob *qj;
-    
-    g_assert(s);
-    g_assert(key);
 
-    qj = g_new(AvahiQueryJob, 1);
+    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;
-    
-    if ((qj->done = done)) 
+    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);
@@ -80,11 +102,11 @@ static AvahiQueryJob* job_new(AvahiQueryScheduler *s, AvahiKey *key, gboolean do
 }
 
 static void job_free(AvahiQueryScheduler *s, AvahiQueryJob *qj) {
-    g_assert(s);
-    g_assert(qj);
+    assert(s);
+    assert(qj);
 
     if (qj->time_event)
-        avahi_time_event_queue_remove(s->time_event_queue, qj->time_event);
+        avahi_time_event_free(qj->time_event);
 
     if (qj->done)
         AVAHI_LLIST_REMOVE(AvahiQueryJob, jobs, s->history, qj);
@@ -92,35 +114,35 @@ static void job_free(AvahiQueryScheduler *s, AvahiQueryJob *qj) {
         AVAHI_LLIST_REMOVE(AvahiQueryJob, jobs, s->jobs, qj);
 
     avahi_key_unref(qj->key);
-    g_free(qj);
+    avahi_free(qj);
 }
 
-static void elapse_callback(AvahiTimeEvent *e, gpointer data);
+static void elapse_callback(AvahiTimeEvent *e, void* data);
 
-static void job_set_elapse_time(AvahiQueryScheduler *s, AvahiQueryJob *qj, guint msec, guint jitter) {
+static void job_set_elapse_time(AvahiQueryScheduler *s, AvahiQueryJob *qj, unsigned msec, unsigned jitter) {
     struct timeval tv;
 
-    g_assert(s);
-    g_assert(qj);
+    assert(s);
+    assert(qj);
 
     avahi_elapse_time(&tv, msec, jitter);
 
     if (qj->time_event)
-        avahi_time_event_queue_update(s->time_event_queue, qj->time_event, &tv);
+        avahi_time_event_update(qj->time_event, &tv);
     else
-        qj->time_event = avahi_time_event_queue_add(s->time_event_queue, &tv, elapse_callback, qj);
+        qj->time_event = avahi_time_event_new(s->time_event_queue, &tv, elapse_callback, qj);
 }
 
 static void job_mark_done(AvahiQueryScheduler *s, AvahiQueryJob *qj) {
-    g_assert(s);
-    g_assert(qj);
+    assert(s);
+    assert(qj);
 
-    g_assert(!qj->done);
+    assert(!qj->done);
 
     AVAHI_LLIST_REMOVE(AvahiQueryJob, jobs, s->jobs, qj);
     AVAHI_LLIST_PREPEND(AvahiQueryJob, jobs, s->history, qj);
 
-    qj->done = TRUE;
+    qj->done = 1;
 
     job_set_elapse_time(s, qj, AVAHI_QUERY_HISTORY_MSEC, 0);
     gettimeofday(&qj->delivery, NULL);
@@ -128,12 +150,17 @@ static void job_mark_done(AvahiQueryScheduler *s, AvahiQueryJob *qj) {
 
 AvahiQueryScheduler *avahi_query_scheduler_new(AvahiInterface *i) {
     AvahiQueryScheduler *s;
-    g_assert(i);
+    assert(i);
+
+    if (!(s = avahi_new(AvahiQueryScheduler, 1))) {
+        avahi_log_error(__FILE__": Out of memory");
+        return NULL; /* OOM */
+    }
 
-    s = g_new(AvahiQueryScheduler, 1);
     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);
@@ -142,35 +169,39 @@ AvahiQueryScheduler *avahi_query_scheduler_new(AvahiInterface *i) {
 }
 
 void avahi_query_scheduler_free(AvahiQueryScheduler *s) {
-    g_assert(s);
+    assert(s);
 
-    g_assert(!s->known_answers);
+    assert(!s->known_answers);
     avahi_query_scheduler_clear(s);
-    g_free(s);
+    avahi_free(s);
 }
 
 void avahi_query_scheduler_clear(AvahiQueryScheduler *s) {
-    g_assert(s);
-    
+    assert(s);
+
     while (s->jobs)
         job_free(s, s->jobs);
     while (s->history)
         job_free(s, s->history);
 }
 
-static gpointer known_answer_walk_callback(AvahiCache *c, AvahiKey *pattern, AvahiCacheEntry *e, gpointer userdata) {
+static void* known_answer_walk_callback(AvahiCache *c, AvahiKey *pattern, AvahiCacheEntry *e, void* userdata) {
     AvahiQueryScheduler *s = userdata;
     AvahiKnownAnswer *ka;
-    
-    g_assert(c);
-    g_assert(pattern);
-    g_assert(e);
-    g_assert(s);
+
+    assert(c);
+    assert(pattern);
+    assert(e);
+    assert(s);
 
     if (avahi_cache_entry_half_ttl(c, e))
         return NULL;
-    
-    ka = g_new0(AvahiKnownAnswer, 1);
+
+    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);
 
@@ -178,34 +209,34 @@ static gpointer known_answer_walk_callback(AvahiCache *c, AvahiKey *pattern, Ava
     return NULL;
 }
 
-static gboolean packet_add_query_job(AvahiQueryScheduler *s, AvahiDnsPacket *p, AvahiQueryJob *qj) {
-    g_assert(s);
-    g_assert(p);
-    g_assert(qj);
+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, FALSE))
-        return FALSE;
+    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 TRUE;
+    return 1;
 }
 
 static void append_known_answers_and_send(AvahiQueryScheduler *s, AvahiDnsPacket *p) {
     AvahiKnownAnswer *ka;
-    guint n;
-    g_assert(s);
-    g_assert(p);
+    unsigned n;
+    assert(s);
+    assert(p);
 
     n = 0;
-    
+
     while ((ka = s->known_answers)) {
-        gboolean too_large = FALSE;
+        int too_large = 0;
 
-        while (!avahi_dns_packet_append_record(p, ka->record, FALSE, 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
@@ -213,7 +244,7 @@ static void append_known_answers_and_send(AvahiQueryScheduler *s, AvahiDnsPacket
                    the owner of the record send it as a response. This
                    has the advantage of a cache refresh. */
 
-                too_large = TRUE;
+                too_large = 1;
                 break;
             }
 
@@ -228,25 +259,25 @@ static void append_known_answers_and_send(AvahiQueryScheduler *s, AvahiDnsPacket
 
         AVAHI_LLIST_REMOVE(AvahiKnownAnswer, known_answer, s->known_answers, ka);
         avahi_record_unref(ka->record);
-        g_free(ka);
+        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(AvahiTimeEvent *e, gpointer data) {
+static void elapse_callback(AVAHI_GCC_UNUSED AvahiTimeEvent *e, void* data) {
     AvahiQueryJob *qj = data;
     AvahiQueryScheduler *s;
     AvahiDnsPacket *p;
-    guint n;
-    gboolean b;
+    unsigned n;
+    int b;
 
-    g_assert(qj);
+    assert(qj);
     s = qj->scheduler;
 
     if (qj->done) {
@@ -255,11 +286,13 @@ static void elapse_callback(AvahiTimeEvent *e, gpointer data) {
         return;
     }
 
-    g_assert(!s->known_answers);
-    
-    p = avahi_dns_packet_new_query(s->interface->hardware->mtu);
+    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);
-    g_assert(b); /* An query must always fit in */
+    assert(b); /* An query must always fit in */
     n = 1;
 
     /* Try to fill up packet with more queries, if available */
@@ -280,12 +313,12 @@ static void elapse_callback(AvahiTimeEvent *e, gpointer data) {
 static AvahiQueryJob* find_scheduled_job(AvahiQueryScheduler *s, AvahiKey *key) {
     AvahiQueryJob *qj;
 
-    g_assert(s);
-    g_assert(key);
+    assert(s);
+    assert(key);
 
     for (qj = s->jobs; qj; qj = qj->jobs_next) {
-        g_assert(!qj->done);
-        
+        assert(!qj->done);
+
         if (avahi_key_equal(qj->key, key))
             return qj;
     }
@@ -295,12 +328,12 @@ static AvahiQueryJob* find_scheduled_job(AvahiQueryScheduler *s, AvahiKey *key)
 
 static AvahiQueryJob* find_history_job(AvahiQueryScheduler *s, AvahiKey *key) {
     AvahiQueryJob *qj;
-    
-    g_assert(s);
-    g_assert(key);
+
+    assert(s);
+    assert(key);
 
     for (qj = s->history; qj; qj = qj->jobs_next) {
-        g_assert(qj->done);
+        assert(qj->done);
 
         if (avahi_key_equal(qj->key, key)) {
             /* Check whether this entry is outdated */
@@ -310,7 +343,7 @@ static AvahiQueryJob* find_history_job(AvahiQueryScheduler *s, AvahiKey *key) {
                 job_free(s, qj);
                 return NULL;
             }
-                
+
             return qj;
         }
     }
@@ -318,62 +351,100 @@ static AvahiQueryJob* find_history_job(AvahiQueryScheduler *s, AvahiKey *key) {
     return NULL;
 }
 
-gboolean avahi_query_scheduler_post(AvahiQueryScheduler *s, AvahiKey *key, gboolean immediately) {
+int avahi_query_scheduler_post(AvahiQueryScheduler *s, AvahiKey *key, int immediately, unsigned *ret_id) {
     struct timeval tv;
     AvahiQueryJob *qj;
-    
-    g_assert(s);
-    g_assert(key);
 
-    if ((qj = find_history_job(s, key))) {
-/*         avahi_log_debug("Query suppressed by local duplicate suppression (history)"); */
-        return FALSE;
-    }
-    
+    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 */
 
-/*         avahi_log_debug("Query suppressed by local duplicate suppression (scheduled)"); */
-        
         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_queue_update(s->time_event_queue, qj->time_event, &qj->delivery);
+            avahi_time_event_update(qj->time_event, &qj->delivery);
         }
 
-        return TRUE;
+        qj->n_posted++;
+
     } else {
-/*         avahi_log_debug("Accepted new query job.\n"); */
 
-        qj = job_new(s, key, FALSE);
+        if (!(qj = job_new(s, key, 0)))
+            return 0; /* OOM */
+
         qj->delivery = tv;
-        qj->time_event = avahi_time_event_queue_add(s->time_event_queue, &qj->delivery, elapse_callback, qj);
-        
-        return TRUE;
+        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;
-    
-    g_assert(s);
-    g_assert(key);
+
+    assert(s);
+    assert(key);
 
     /* This function is called whenever an incoming query was
-     * receieved. We drop scheduled queries that match. The keyword is
+     * received. We drop scheduled queries that match. The keyword is
      * "DUPLICATE QUESTION SUPPRESION". */
 
     if ((qj = find_scheduled_job(s, key))) {
-/*         avahi_log_debug("Query suppressed by distributed duplicate suppression"); */
         job_mark_done(s, qj);
         return;
     }
-    
-    qj = job_new(s, key, TRUE);
+
+    /* 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;
+}