Bluetooth: Add simple timeout for connection establishment

Adds fiber which starts with some specified delay.
If the fiber is not cancelled, bt_disconnect is called to
cancel creation of connection.

Change-Id: I06667d970ba3398f205f19f1d2e76ab6c283f274
Signed-off-by: Mariusz Skamra <mariusz.skamra@tieto.com>

net/bluetooth/Kconfig

@@ -34,6 +34,7 @@ config	BLUETOOTH
 	bool
 	prompt "Bluetooth LE support [EXPERIMENTAL]"
 	default n
+	select NANO_TIMEOUTS
 	help
 	  This option enables Bluetooth Low Energy support.
 

net/bluetooth/conn.c

@@ -318,8 +318,8 @@ void bt_conn_set_state(struct bt_conn *conn, bt_conn_state_t state)
 	switch (conn->state){
 	case BT_CONN_CONNECTED:
 		nano_fifo_init(&conn->tx_queue);
-		fiber_start(conn->tx_stack, sizeof(conn->tx_stack),
+		fiber_start(conn->stack, sizeof(conn->stack), conn_tx_fiber,
-			    conn_tx_fiber, (int)bt_conn_get(conn), 0, 7, 0);
+			    (int)bt_conn_get(conn), 0, 7, 0);
 		break;
 	case BT_CONN_DISCONNECTED:
 		/* Send dummy buffer to wake up and stop the tx fiber
@@ -505,6 +505,15 @@ static int bt_hci_connect_le_cancel(struct bt_conn *conn)
 {
 	int err;
 
+	if (conn->timeout) {
+		fiber_fiber_delayed_start_cancel(conn->timeout);
+
+		conn->timeout = NULL;
+
+		/* Drop the reference took by timeout fiber */
+		bt_conn_put(conn);
+	}
+
 	err = bt_hci_cmd_send(BT_HCI_OP_LE_CREATE_CONN_CANCEL, NULL);
 	if (err) {
 		return err;

net/bluetooth/conn_internal.h

@@ -82,8 +82,14 @@ struct bt_conn {
 
 	bt_conn_state_t		state;
 
-	/* TX fiber stack */
+	/* Handle allowing to cancel timeout fiber */
-	BT_STACK(tx_stack, 256);
+	void			*timeout;
+
+	/* Stack for Tx fiber and timeout fiber.
+	 * Since this fibers don't overlap, one stack can be used by both of
+	 * them.
+	 */
+	BT_STACK(stack, 256);
 };
 
 /* Process incoming data for a connection */

net/bluetooth/hci_core.c

@@ -58,6 +58,8 @@
 #define ACL_IN_MAX	7
 #define ACL_OUT_MAX	7
 
+#define BT_CREATE_CONN_TIMEOUT			(3 * sys_clock_ticks_per_sec)
+
 /* Stacks for the fibers */
 static BT_STACK_NOINIT(rx_fiber_stack, 1024);
 static BT_STACK_NOINIT(rx_prio_fiber_stack, 256);
@@ -329,7 +331,7 @@ static void analyze_stacks(struct bt_conn *conn, struct bt_conn **ref)
 		      sizeof(rx_prio_fiber_stack), stack_growth);
 	analyze_stack("cmd tx stack", cmd_tx_fiber_stack,
 		      sizeof(cmd_tx_fiber_stack), stack_growth);
-	analyze_stack("conn tx stack", conn->tx_stack, sizeof(conn->tx_stack),
+	analyze_stack("conn tx stack", conn->stack, sizeof(conn->stack),
 		      stack_growth);
 }
 #else
@@ -739,6 +741,15 @@ static void le_conn_complete(struct bt_buf *buf)
 		conn = bt_conn_lookup_state(&evt->peer_addr, BT_CONN_CONNECT);
 	}
 
+	if (conn && conn->timeout) {
+		fiber_fiber_delayed_start_cancel(conn->timeout);
+
+		conn->timeout = NULL;
+
+		/* Drop the reference took by timeout fiber */
+		bt_conn_put(conn);
+	}
+
 	if (evt->status) {
 		if (!conn) {
 			return;
@@ -783,6 +794,17 @@ static void le_conn_complete(struct bt_buf *buf)
 	bt_le_scan_update();
 }
 
+static void timeout_fiber(int arg1, int arg2)
+{
+	struct bt_conn *conn = (struct bt_conn *)arg1;
+	ARG_UNUSED(arg2);
+
+	conn->timeout = NULL;
+
+	bt_conn_disconnect(conn, BT_HCI_ERR_REMOTE_USER_TERM_CONN);
+	bt_conn_put(conn);
+}
+
 static void check_pending_conn(const bt_addr_le_t *addr, uint8_t evtype,
 			       struct bt_keys *keys)
 {
@@ -813,6 +835,13 @@ static void check_pending_conn(const bt_addr_le_t *addr, uint8_t evtype,
 
 	bt_conn_set_state(conn, BT_CONN_CONNECT);
 
+	/* Add LE Create Connection timeout */
+	conn->timeout = fiber_fiber_delayed_start(conn->stack,
+						  sizeof(conn->stack),
+						  timeout_fiber,
+						  (int)bt_conn_get(conn), 0, 7,
+						  0, BT_CREATE_CONN_TIMEOUT);
+
 done:
 	bt_conn_put(conn);
 }