conntrackd: fix checking of return value of queue_add()

Most callers of queue_add() assume that it returns != 0 in case of
success. However, it may return -1 in case that the queue gets full.
In that case, most callers have to:

- release the object that they want to enqueue.
- decrement the refcount, in case they have bumped it.

However, most of these callers are using the tx_queue which currently
has no limit in size at all. This fix is necessary in case that I
decide to limit the size of the transmission queue in the future
(which makes a lot of sense indeed).

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

3 files changed, 13 insertions, 9 deletions

diff --git a/src/sync-alarm.c b/src/sync-alarm.c
index 0fc7943..b555dd5 100644
--- a/src/sync-alarm.c
+++ b/src/sync-alarm.c
@@ -111,7 +111,7 @@ static void alarm_enqueue(struct cache_object *obj, int query)
 {
 	struct cache_alarm *ca =
 		cache_get_extra(STATE(mode)->internal->data, obj);
-	if (queue_add(STATE_SYNC(tx_queue), &ca->qnode))
+	if (queue_add(STATE_SYNC(tx_queue), &ca->qnode) > 0)
 		cache_object_get(obj);
 }
 
diff --git a/src/sync-ftfw.c b/src/sync-ftfw.c
index 86edeab..581b5ca 100644
--- a/src/sync-ftfw.c
+++ b/src/sync-ftfw.c
@@ -107,7 +107,8 @@ static void tx_queue_add_ctlmsg(uint32_t flags, uint32_t from, uint32_t to)
 	ack->from	= from;
 	ack->to		= to;
 
-	queue_add(STATE_SYNC(tx_queue), &qobj->qnode);
+	if (queue_add(STATE_SYNC(tx_queue), &qobj->qnode) < 0)
+		queue_object_free(qobj);
 }
 
 static void tx_queue_add_ctlmsg2(uint32_t flags)
@@ -123,7 +124,8 @@ static void tx_queue_add_ctlmsg2(uint32_t flags)
 	ctl->type 	= NET_T_CTL;
 	ctl->flags	= flags;
 
-	queue_add(STATE_SYNC(tx_queue), &qobj->qnode);
+	if (queue_add(STATE_SYNC(tx_queue), &qobj->qnode) < 0)
+		queue_object_free(qobj);
 }
 
 /* this function is called from the alarm framework */
@@ -173,7 +175,7 @@ static int do_cache_to_tx(void *data1, void *data2)
 		queue_del(&cn->qnode);
 		queue_add(STATE_SYNC(tx_queue), &cn->qnode);
 	} else {
-		if (queue_add(STATE_SYNC(tx_queue), &cn->qnode))
+		if (queue_add(STATE_SYNC(tx_queue), &cn->qnode) > 0)
 			cache_object_get(obj);
 	}
 	return 0;
@@ -554,7 +556,7 @@ static void ftfw_enqueue(struct cache_object *obj, int type)
 		queue_del(&cn->qnode);
 		queue_add(STATE_SYNC(tx_queue), &cn->qnode);
 	} else {
-		if (queue_add(STATE_SYNC(tx_queue), &cn->qnode))
+		if (queue_add(STATE_SYNC(tx_queue), &cn->qnode) > 0)
 			cache_object_get(obj);
 	}
 }
diff --git a/src/sync-notrack.c b/src/sync-notrack.c
index c4ad941..06af58b 100644
--- a/src/sync-notrack.c
+++ b/src/sync-notrack.c
@@ -68,7 +68,8 @@ static void tx_queue_add_ctlmsg(uint32_t flags, uint32_t from, uint32_t to)
 	ack->from	= from;
 	ack->to		= to;
 
-	queue_add(STATE_SYNC(tx_queue), &qobj->qnode);
+	if (queue_add(STATE_SYNC(tx_queue), &qobj->qnode) < 0)
+		queue_object_free(qobj);
 }
 
 static int do_cache_to_tx(void *data1, void *data2)
@@ -76,7 +77,7 @@ static int do_cache_to_tx(void *data1, void *data2)
 	struct cache_object *obj = data2;
 	struct cache_notrack *cn =
 		cache_get_extra(STATE(mode)->internal->data, obj);
-	if (queue_add(STATE_SYNC(tx_queue), &cn->qnode))
+	if (queue_add(STATE_SYNC(tx_queue), &cn->qnode) > 0)
 		cache_object_get(obj);
 	return 0;
 }
@@ -219,7 +220,7 @@ static void notrack_enqueue(struct cache_object *obj, int query)
 {
 	struct cache_notrack *cn =
 		cache_get_extra(STATE(mode)->internal->data, obj);
-	if (queue_add(STATE_SYNC(tx_queue), &cn->qnode))
+	if (queue_add(STATE_SYNC(tx_queue), &cn->qnode) > 0)
 		cache_object_get(obj);
 }
 
@@ -236,7 +237,8 @@ static void tx_queue_add_ctlmsg2(uint32_t flags)
 	ctl->type	= NET_T_CTL;
 	ctl->flags	= flags;
 
-	queue_add(STATE_SYNC(tx_queue), &qobj->qnode);
+	if (queue_add(STATE_SYNC(tx_queue), &qobj->qnode) < 0)
+		queue_object_free(qobj);
 }
 
 static void do_alive_alarm(struct alarm_block *a, void *data)