Bluetooth: Mesh: Add back-off to secure beacons

adding back-off mechanism to mesh secure beacon behaviour

Signed-off-by: Alperen Sener <[email protected]>

Author: m-alperen-sener

subsys/bluetooth/mesh/beacon.c

@@ -101,12 +101,15 @@ static bool secure_beacon_send(struct bt_mesh_subnet *sub, void *cb_data)
 	uint32_t now = k_uptime_get_32();
 	struct net_buf *buf;
 	uint32_t time_diff;
+	uint32_t time_since_last_recv;
 
 	BT_DBG("");
 
 	time_diff = now - sub->beacon_sent;
+	time_since_last_recv = now - sub->beacon_recv;
 	if (time_diff < (600 * MSEC_PER_SEC) &&
-		time_diff < BEACON_THRESHOLD(sub)) {
+		(time_diff < BEACON_THRESHOLD(sub) ||
+		 time_since_last_recv < (10 * MSEC_PER_SEC))) {
 		return false;
 	}
 
@@ -374,6 +377,7 @@ static void secure_beacon_recv(struct net_buf_simple *buf)
 	if (bt_mesh_beacon_enabled() &&
 	    sub->beacons_cur < 0xff) {
 		sub->beacons_cur++;
+		sub->beacon_recv = k_uptime_get_32();
 	}
 }
 

subsys/bluetooth/mesh/subnet.h

@@ -36,6 +36,7 @@ struct bt_mesh_net_cred {
 /** Subnet instance. */
 struct bt_mesh_subnet {
 	uint32_t beacon_sent;        /* Timestamp of last sent beacon */
+	uint32_t beacon_recv;        /* Timestamp of last received beacon */
 	uint8_t  beacons_last;       /* Number of beacons during last
 				      * observation window
 				      */