tipc: fix random link reset problem

In the function tipc_sk_rcv(), the stack variable 'err'
is only initialized to TIPC_ERR_NO_PORT for the first
iteration over the link input queue. If a chain of messages
are received from a link, failure to lookup the socket for
any but the first message will cause the message to bounce back
out on a random link.
We fix this by properly initializing err.
Signed-off-by: Erik Hugne <erik.hugne@ericsson.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/tipc/socket.c

@@ -1764,13 +1764,14 @@ static int tipc_sk_enqueue(struct sk_buff_head *inputq, struct sock *sk,
 int tipc_sk_rcv(struct net *net, struct sk_buff_head *inputq)
 {
 	u32 dnode, dport = 0;
-	int err = -TIPC_ERR_NO_PORT;
+	int err;
 	struct sk_buff *skb;
 	struct tipc_sock *tsk;
 	struct tipc_net *tn;
 	struct sock *sk;
 
 	while (skb_queue_len(inputq)) {
+		err = -TIPC_ERR_NO_PORT;
 		skb = NULL;
 		dport = tipc_skb_peek_port(inputq, dport);
 		tsk = tipc_sk_lookup(net, dport);