conntrackd: add alive control messages to notrack mode

This patch adds the alive control message to the notrack mode.
This helps to diagnose problems in the synchronization and
the state of the channel, specifically for TCP-based channels.

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

1 files changed, 39 insertions, 0 deletions

diff --git a/src/sync-notrack.c b/src/sync-notrack.c
index 14ecde5..d9f273e 100644
--- a/src/sync-notrack.c
+++ b/src/sync-notrack.c
@@ -26,6 +26,11 @@
 
 #include <string.h>
 
+static struct alarm_block alive_alarm;
+
+/* XXX: alive message expiration configurable */
+#define ALIVE_INT 1
+
 struct cache_notrack {
 	struct queue_node	qnode;
 };
@@ -106,6 +111,9 @@ static int digest_msg(const struct nethdr *net)
 		return MSG_CTL;
 	}
 
+	if (IS_ALIVE(net))
+		return MSG_CTL;
+
 	return MSG_BAD;
 }
 
@@ -162,6 +170,7 @@ static int tx_queue_xmit(struct queue_node *n, const void *data2)
 static void notrack_xmit(void)
 {
 	queue_iterate(STATE_SYNC(tx_queue), NULL, tx_queue_xmit);
+	add_alarm(&alive_alarm, ALIVE_INT, 0);
 }
 
 static void notrack_enqueue(struct cache_object *obj, int query)
@@ -171,10 +180,40 @@ static void notrack_enqueue(struct cache_object *obj, int query)
 		cache_object_get(obj);
 }
 
+static void tx_queue_add_ctlmsg2(uint32_t flags)
+{
+	struct queue_object *qobj;
+	struct nethdr *ctl;
+
+	qobj = queue_object_new(Q_ELEM_CTL, sizeof(struct nethdr_ack));
+	if (qobj == NULL)
+		return;
+
+	ctl		= (struct nethdr *)qobj->data;
+	ctl->type	= NET_T_CTL;
+	ctl->flags	= flags;
+
+	queue_add(STATE_SYNC(tx_queue), &qobj->qnode);
+}
+
+static void do_alive_alarm(struct alarm_block *a, void *data)
+{
+	tx_queue_add_ctlmsg2(NET_F_ALIVE);
+	add_alarm(&alive_alarm, ALIVE_INT, 0);
+}
+
+static int notrack_init(void)
+{
+	init_alarm(&alive_alarm, NULL, do_alive_alarm);
+	add_alarm(&alive_alarm, ALIVE_INT, 0);
+	return 0;
+}
+
 struct sync_mode sync_notrack = {
 	.internal_cache_flags	= NO_FEATURES,
 	.external_cache_flags	= NO_FEATURES,
 	.internal_cache_extra	= &cache_notrack_extra,
+	.init			= notrack_init,
 	.local			= notrack_local,
 	.recv			= notrack_recv,
 	.enqueue		= notrack_enqueue,