-/* $Id$ */
-
/***
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
#include <string.h>
#include <stdlib.h>
+#include <time.h>
#include <avahi-common/timeval.h>
#include <avahi-common/malloc.h>
#include "cache.h"
#include "log.h"
-
-#define AVAHI_MAX_CACHE_ENTRIES 500
+#include "rr-util.h"
static void remove_entry(AvahiCache *c, AvahiCacheEntry *e) {
AvahiCacheEntry *t;
/* Remove from linked list */
AVAHI_LLIST_REMOVE(AvahiCacheEntry, entry, c->entries, e);
-
+
if (e->time_event)
avahi_time_event_free(e->time_event);
avahi_multicast_lookup_engine_notify(c->server->multicast_lookup_engine, c->interface, e->record, AVAHI_BROWSER_REMOVE);
-
+
avahi_record_unref(e->record);
-
+
avahi_free(e);
- assert(c->n_entries-- >= 1);
+ assert(c->n_entries >= 1);
+ --c->n_entries;
}
AvahiCache *avahi_cache_new(AvahiServer *server, AvahiInterface *iface) {
avahi_log_error(__FILE__": Out of memory.");
return NULL; /* OOM */
}
-
+
c->server = server;
c->interface = iface;
AVAHI_LLIST_HEAD_INIT(AvahiCacheEntry, c->entries);
c->n_entries = 0;
-
+
+ c->last_rand_timestamp = 0;
+
return c;
}
while (c->entries)
remove_entry(c, c->entries);
assert(c->n_entries == 0);
-
+
avahi_hashmap_free(c->hashmap);
-
+
avahi_free(c);
}
-AvahiCacheEntry *avahi_cache_lookup_key(AvahiCache *c, AvahiKey *k) {
+static AvahiCacheEntry *lookup_key(AvahiCache *c, AvahiKey *k) {
assert(c);
assert(k);
assert(!avahi_key_is_pattern(k));
-
+
return avahi_hashmap_lookup(c->hashmap, k);
}
void* avahi_cache_walk(AvahiCache *c, AvahiKey *pattern, AvahiCacheWalkCallback cb, void* userdata) {
void* ret;
-
+
assert(c);
assert(pattern);
assert(cb);
-
+
if (avahi_key_is_pattern(pattern)) {
AvahiCacheEntry *e, *n;
-
+
for (e = c->entries; e; e = n) {
n = e->entry_next;
-
+
if (avahi_key_pattern_match(pattern, e->record->key))
if ((ret = cb(c, pattern, e, userdata)))
return ret;
}
-
+
} else {
AvahiCacheEntry *e, *n;
- for (e = avahi_cache_lookup_key(c, pattern); e; e = n) {
+ for (e = lookup_key(c, pattern); e; e = n) {
n = e->by_key_next;
-
+
if ((ret = cb(c, pattern, e, userdata)))
return ret;
}
return NULL;
}
-AvahiCacheEntry *avahi_cache_lookup_record(AvahiCache *c, AvahiRecord *r) {
+static AvahiCacheEntry *lookup_record(AvahiCache *c, AvahiRecord *r) {
assert(c);
assert(r);
static void elapse_func(AvahiTimeEvent *t, void *userdata) {
AvahiCacheEntry *e = userdata;
/* char *txt; */
-
+ unsigned percent = 0;
+
assert(t);
assert(e);
/* txt = avahi_record_to_string(e->record); */
- if (e->state == AVAHI_CACHE_FINAL) {
- remove_entry(e->cache, e);
+ switch (e->state) {
+
+ case AVAHI_CACHE_EXPIRY_FINAL:
+ case AVAHI_CACHE_POOF_FINAL:
+ case AVAHI_CACHE_GOODBYE_FINAL:
+ case AVAHI_CACHE_REPLACE_FINAL:
+
+ remove_entry(e->cache, e);
+
+ e = NULL;
/* avahi_log_debug("Removing entry from cache due to expiration (%s)", txt); */
- } else {
- unsigned percent = 0;
-
- switch (e->state) {
- case AVAHI_CACHE_VALID:
- e->state = AVAHI_CACHE_EXPIRY1;
- percent = 85;
- break;
-
- case AVAHI_CACHE_EXPIRY1:
- e->state = AVAHI_CACHE_EXPIRY2;
- percent = 90;
- break;
- case AVAHI_CACHE_EXPIRY2:
- e->state = AVAHI_CACHE_EXPIRY3;
- percent = 95;
- break;
-
- case AVAHI_CACHE_EXPIRY3:
- e->state = AVAHI_CACHE_FINAL;
- percent = 100;
- break;
-
- default:
- ;
- }
+ break;
+
+ case AVAHI_CACHE_VALID:
+ case AVAHI_CACHE_POOF:
+ e->state = AVAHI_CACHE_EXPIRY1;
+ percent = 85;
+ break;
+
+ case AVAHI_CACHE_EXPIRY1:
+ e->state = AVAHI_CACHE_EXPIRY2;
+ percent = 90;
+ break;
+ case AVAHI_CACHE_EXPIRY2:
+ e->state = AVAHI_CACHE_EXPIRY3;
+ percent = 95;
+ break;
+
+ case AVAHI_CACHE_EXPIRY3:
+ e->state = AVAHI_CACHE_EXPIRY_FINAL;
+ percent = 100;
+ break;
+ }
+
+ if (e) {
assert(percent > 0);
- /* Request a cache update, if we are subscribed to this entry */
- if (avahi_querier_exists(e->cache->interface, e->record->key)) {
-/* avahi_log_debug("Requesting cache entry update at %i%% for %s.", percent, txt); */
- avahi_interface_post_query(e->cache->interface, e->record->key, 1);
- }
+ /* Request a cache update if we are subscribed to this entry */
+ if (avahi_querier_shall_refresh_cache(e->cache->interface, e->record->key))
+ avahi_interface_post_query(e->cache->interface, e->record->key, 0, NULL);
/* Check again later */
next_expiry(e->cache, e, percent);
+
}
/* avahi_free(txt); */
static void update_time_event(AvahiCache *c, AvahiCacheEntry *e) {
assert(c);
assert(e);
-
+
if (e->time_event)
avahi_time_event_update(e->time_event, &e->expiry);
else
static void next_expiry(AvahiCache *c, AvahiCacheEntry *e, unsigned percent) {
AvahiUsec usec, left, right;
-
+ time_t now;
+
assert(c);
assert(e);
assert(percent > 0 && percent <= 100);
-
+
usec = (AvahiUsec) e->record->ttl * 10000;
left = usec * percent;
right = usec * (percent+2); /* 2% jitter */
- usec = left + (AvahiUsec) ((double) (right-left) * rand() / (RAND_MAX+1.0));
-
+ now = time(NULL);
+
+ if (now >= c->last_rand_timestamp + 10) {
+ c->last_rand = rand();
+ c->last_rand_timestamp = now;
+ }
+
+ usec = left + (AvahiUsec) ((double) (right-left) * c->last_rand / (RAND_MAX+1.0));
+
e->expiry = e->timestamp;
avahi_timeval_add(&e->expiry, usec);
-
+
/* g_message("wake up in +%lu seconds", e->expiry.tv_sec - e->timestamp.tv_sec); */
-
+
update_time_event(c, e);
}
-static void expire_in_one_second(AvahiCache *c, AvahiCacheEntry *e) {
+static void expire_in_one_second(AvahiCache *c, AvahiCacheEntry *e, AvahiCacheEntryState state) {
assert(c);
assert(e);
-
- e->state = AVAHI_CACHE_FINAL;
+
+ e->state = state;
gettimeofday(&e->expiry, NULL);
avahi_timeval_add(&e->expiry, 1000000); /* 1s */
update_time_event(c, e);
void avahi_cache_update(AvahiCache *c, AvahiRecord *r, int cache_flush, const AvahiAddress *a) {
/* char *txt; */
-
+
assert(c);
assert(r && r->ref >= 1);
AvahiCacheEntry *e;
- if ((e = avahi_cache_lookup_record(c, r)))
- expire_in_one_second(c, e);
+ if ((e = lookup_record(c, r)))
+ expire_in_one_second(c, e, AVAHI_CACHE_GOODBYE_FINAL);
} else {
AvahiCacheEntry *e = NULL, *first;
/* This is an update request */
- if ((first = avahi_cache_lookup_key(c, r->key))) {
-
+ if ((first = lookup_key(c, r->key))) {
+
if (cache_flush) {
/* For unique entries drop all entries older than one second */
t = avahi_timeval_diff(&now, &e->timestamp);
if (t > 1000000)
- expire_in_one_second(c, e);
+ expire_in_one_second(c, e, AVAHI_CACHE_REPLACE_FINAL);
}
}
-
+
/* Look for exactly the same entry */
for (e = first; e; e = e->by_key_next)
if (avahi_record_equal_no_ttl(e->record, r))
break;
}
-
+
if (e) {
-
+
/* avahi_log_debug("found matching cache entry"); */
/* We need to update the hash table key if we replace the
* record */
if (e->by_key_prev == NULL)
avahi_hashmap_replace(c->hashmap, r->key, e);
-
+
/* Update the record */
avahi_record_unref(e->record);
e->record = avahi_record_ref(r);
/* avahi_log_debug("cache: updating %s", txt); */
-
+
} else {
/* No entry found, therefore we create a new one */
-
+
/* avahi_log_debug("cache: couldn't find matching cache entry for %s", txt); */
- if (c->n_entries >= AVAHI_MAX_CACHE_ENTRIES)
+ if (c->n_entries >= c->server->config.n_cache_entries_max)
return;
if (!(e = avahi_new(AvahiCacheEntry, 1))) {
/* Notify subscribers */
avahi_multicast_lookup_engine_notify(c->server->multicast_lookup_engine, c->interface, e->record, AVAHI_BROWSER_NEW);
- }
-
+ }
+
e->origin = *a;
e->timestamp = now;
next_expiry(c, e, 80);
if (!(t = avahi_record_to_string(e->record)))
continue; /* OOM */
-
+
dump_data->callback(t, dump_data->userdata);
avahi_free(t);
}
int avahi_cache_entry_half_ttl(AvahiCache *c, AvahiCacheEntry *e) {
struct timeval now;
unsigned age;
-
+
assert(c);
assert(e);
age = (unsigned) (avahi_timeval_diff(&now, &e->timestamp)/1000000);
/* avahi_log_debug("age: %lli, ttl/2: %u", age, e->record->ttl); */
-
+
return age >= e->record->ttl/2;
}
while (c->entries)
remove_entry(c, c->entries);
}
+
+/*** Passive observation of failure ***/
+
+static void* start_poof_callback(AvahiCache *c, AvahiKey *pattern, AvahiCacheEntry *e, void *userdata) {
+ AvahiAddress *a = userdata;
+ struct timeval now;
+
+ assert(c);
+ assert(pattern);
+ assert(e);
+ assert(a);
+
+ gettimeofday(&now, NULL);
+
+ switch (e->state) {
+ case AVAHI_CACHE_VALID:
+
+ /* The entry was perfectly valid till, now, so let's enter
+ * POOF mode */
+
+ e->state = AVAHI_CACHE_POOF;
+ e->poof_address = *a;
+ e->poof_timestamp = now;
+ e->poof_num = 0;
+
+ break;
+
+ case AVAHI_CACHE_POOF:
+ if (avahi_timeval_diff(&now, &e->poof_timestamp) < 1000000)
+ break;
+
+ e->poof_timestamp = now;
+ e->poof_address = *a;
+ e->poof_num ++;
+
+ /* This is the 4th time we got no response, so let's
+ * fucking remove this entry. */
+ if (e->poof_num > 3)
+ expire_in_one_second(c, e, AVAHI_CACHE_POOF_FINAL);
+ break;
+
+ default:
+ ;
+ }
+
+ return NULL;
+}
+
+void avahi_cache_start_poof(AvahiCache *c, AvahiKey *key, const AvahiAddress *a) {
+ assert(c);
+ assert(key);
+
+ avahi_cache_walk(c, key, start_poof_callback, (void*) a);
+}
+
+void avahi_cache_stop_poof(AvahiCache *c, AvahiRecord *record, const AvahiAddress *a) {
+ AvahiCacheEntry *e;
+
+ assert(c);
+ assert(record);
+ assert(a);
+
+ if (!(e = lookup_record(c, record)))
+ return;
+
+ /* This function is called for each response suppression
+ record. If the matching cache entry is in POOF state and the
+ query address is the same, we put it back into valid mode */
+
+ if (e->state == AVAHI_CACHE_POOF || e->state == AVAHI_CACHE_POOF_FINAL)
+ if (avahi_address_cmp(a, &e->poof_address) == 0) {
+ e->state = AVAHI_CACHE_VALID;
+ next_expiry(c, e, 80);
+ }
+}
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