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-rw-r--r--avahi-core/cache.c137
-rw-r--r--avahi-core/cache.h15
-rw-r--r--avahi-core/server.c5
3 files changed, 124 insertions, 33 deletions
diff --git a/avahi-core/cache.c b/avahi-core/cache.c
index 6332b12..23e9036 100644
--- a/avahi-core/cache.c
+++ b/avahi-core/cache.c
@@ -165,41 +165,48 @@ static void next_expiry(AvahiCache *c, AvahiCacheEntry *e, unsigned percent);
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;
+ break;
+
+ case AVAHI_CACHE_VALID:
+ case AVAHI_CACHE_POOF:
+ e->state = AVAHI_CACHE_EXPIRY1;
+ percent = 85;
+ break;
- case AVAHI_CACHE_EXPIRY3:
- e->state = AVAHI_CACHE_FINAL;
- percent = 100;
- 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;
+ }
- default:
- ;
- }
+ if (e) {
assert(percent > 0);
@@ -208,9 +215,10 @@ static void elapse_func(AvahiTimeEvent *t, void *userdata) {
/* avahi_log_debug("Requesting cache entry update at %i%% for %s.", percent, txt); */
avahi_interface_post_query(e->cache->interface, e->record->key, 1);
}
-
+
/* Check again later */
next_expiry(e->cache, e, percent);
+
}
/* avahi_free(txt); */
@@ -248,11 +256,11 @@ static void next_expiry(AvahiCache *c, AvahiCacheEntry *e, unsigned percent) {
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);
@@ -272,7 +280,7 @@ void avahi_cache_update(AvahiCache *c, AvahiRecord *r, int cache_flush, const Av
AvahiCacheEntry *e;
if ((e = avahi_cache_lookup_record(c, r)))
- expire_in_one_second(c, e);
+ expire_in_one_second(c, e, AVAHI_CACHE_GOODBYE_FINAL);
} else {
AvahiCacheEntry *e = NULL, *first;
@@ -293,7 +301,7 @@ void avahi_cache_update(AvahiCache *c, AvahiRecord *r, int cache_flush, const Av
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);
}
}
@@ -421,3 +429,70 @@ void avahi_cache_flush(AvahiCache *c) {
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;
+
+ assert(c);
+ assert(pattern);
+ assert(e);
+ assert(a);
+
+ 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;
+
+ break;
+
+ case AVAHI_CACHE_POOF:
+
+ /* This is the second time we got no response, so let's
+ * fucking remove this entry. */
+
+ 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, a);
+}
+
+void avahi_cache_stop_poof(AvahiCache *c, AvahiRecord *record, const AvahiAddress *a) {
+ AvahiCacheEntry *e;
+
+ assert(c);
+ assert(record);
+ assert(a);
+
+ if (!(e = avahi_cache_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);
+ }
+}
+
+
+
diff --git a/avahi-core/cache.h b/avahi-core/cache.h
index fa723e9..bd1cd6c 100644
--- a/avahi-core/cache.h
+++ b/avahi-core/cache.h
@@ -35,7 +35,11 @@ typedef enum {
AVAHI_CACHE_EXPIRY1,
AVAHI_CACHE_EXPIRY2,
AVAHI_CACHE_EXPIRY3,
- AVAHI_CACHE_FINAL
+ AVAHI_CACHE_EXPIRY_FINAL,
+ AVAHI_CACHE_POOF, /* Passive observation of failure */
+ AVAHI_CACHE_POOF_FINAL,
+ AVAHI_CACHE_GOODBYE_FINAL,
+ AVAHI_CACHE_REPLACE_FINAL
} AvahiCacheEntryState;
typedef struct AvahiCacheEntry AvahiCacheEntry;
@@ -52,6 +56,8 @@ struct AvahiCacheEntry {
AvahiCacheEntryState state;
AvahiTimeEvent *time_event;
+ AvahiAddress poof_address;
+
AVAHI_LLIST_FIELDS(AvahiCacheEntry, by_key);
AVAHI_LLIST_FIELDS(AvahiCacheEntry, entry);
};
@@ -83,6 +89,13 @@ void* avahi_cache_walk(AvahiCache *c, AvahiKey *pattern, AvahiCacheWalkCallback
int avahi_cache_entry_half_ttl(AvahiCache *c, AvahiCacheEntry *e);
+/** Start the "Passive observation of Failure" algorithm for all
+ * records of the specified key. The specified address is */
+void avahi_cache_start_poof(AvahiCache *c, AvahiKey *key, const AvahiAddress *a);
+
+/* Stop a previously started POOF algorithm for a record. (Used for response suppresions records */
+void avahi_cache_stop_poof(AvahiCache *c, AvahiRecord *record, const AvahiAddress *a);
+
void avahi_cache_flush(AvahiCache *c);
#endif
diff --git a/avahi-core/server.c b/avahi-core/server.c
index 2714298..dc63c67 100644
--- a/avahi-core/server.c
+++ b/avahi-core/server.c
@@ -613,8 +613,10 @@ static void handle_query_packet(AvahiServer *s, AvahiDnsPacket *p, AvahiInterfac
goto fail;
}
- if (!legacy_unicast && !from_local_iface)
+ if (!legacy_unicast && !from_local_iface) {
reflect_query(s, i, key);
+ avahi_cache_start_poof(i->cache, key, a);
+ }
if (avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_ANCOUNT) == 0 &&
!(avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS) & AVAHI_DNS_FLAG_TC))
@@ -641,6 +643,7 @@ static void handle_query_packet(AvahiServer *s, AvahiDnsPacket *p, AvahiInterfac
if (handle_conflict(s, i, record, unique, a)) {
avahi_response_scheduler_suppress(i->response_scheduler, record, a);
avahi_record_list_drop(s->record_list, record);
+ avahi_cache_stop_poof(i->cache, record, a);
}
avahi_record_unref(record);
generated by cgit (git 2.34.1) at 2024-05-25 02:47:46 +0000