[Bluetooth] Check for L2CAP reliability

The L2CAP sockets can now set LM_RELIABLE flag and get notification
when a reliability problem with the ACL connection is detected. The
Bluetooth qualification tests require this functionality.
Signed-off-by: Maxim Krasnyansky <maxk@qualcomm.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

net/bluetooth/l2cap.c

@@ -1100,6 +1100,22 @@ static void l2cap_conn_ready(struct l2cap_conn *conn)
 	read_unlock(&l->lock);
 }
 
+/* Notify sockets that we cannot guaranty reliability anymore */
+static void l2cap_conn_unreliable(struct l2cap_conn *conn, int err)
+{
+	struct l2cap_chan_list *l = &conn->chan_list;
+	struct sock *sk;
+
+	BT_DBG("conn %p", conn);
+
+	read_lock(&l->lock);
+	for (sk = l->head; sk; sk = l2cap_pi(sk)->next_c) {
+		if (l2cap_pi(sk)->link_mode & L2CAP_LM_RELIABLE)
+			sk->sk_err = err;
+	}
+	read_unlock(&l->lock);
+}
+
 static void l2cap_chan_ready(struct sock *sk)
 {
 	struct sock *parent = bt_sk(sk)->parent;
@@ -2045,10 +2061,12 @@ static int l2cap_recv_acldata(struct hci_conn *hcon, struct sk_buff *skb, u16 fl
 			kfree_skb(conn->rx_skb);
 			conn->rx_skb = NULL;
 			conn->rx_len = 0;
+			l2cap_conn_unreliable(conn, ECOMM);
 		}
 
 		if (skb->len < 2) {
 			BT_ERR("Frame is too short (len %d)", skb->len);
+			l2cap_conn_unreliable(conn, ECOMM);
 			goto drop;
 		}
 
@@ -2066,6 +2084,7 @@ static int l2cap_recv_acldata(struct hci_conn *hcon, struct sk_buff *skb, u16 fl
 		if (skb->len > len) {
 			BT_ERR("Frame is too long (len %d, expected len %d)",
 				skb->len, len);
+			l2cap_conn_unreliable(conn, ECOMM);
 			goto drop;
 		}
 
@@ -2080,6 +2099,7 @@ static int l2cap_recv_acldata(struct hci_conn *hcon, struct sk_buff *skb, u16 fl
 
 		if (!conn->rx_len) {
 			BT_ERR("Unexpected continuation frame (len %d)", skb->len);
+			l2cap_conn_unreliable(conn, ECOMM);
 			goto drop;
 		}
 
@@ -2089,6 +2109,7 @@ static int l2cap_recv_acldata(struct hci_conn *hcon, struct sk_buff *skb, u16 fl
 			kfree_skb(conn->rx_skb);
 			conn->rx_skb = NULL;
 			conn->rx_len = 0;
+			l2cap_conn_unreliable(conn, ECOMM);
 			goto drop;
 		}