tipc: split up function tipc_msg_eval()

The function tipc_msg_eval() is in reality doing two related, but
different tasks. First it tries to find a new destination for named
messages, in case there was no first lookup, or if the first lookup
failed. Second, it does what its name suggests, evaluating the validity
of the message and its destination, and returning an appropriate error
code depending on the result.

This is confusing, and in this commit we choose to break it up into two
functions. A new function, tipc_msg_lookup_dest(), first attempts to find
a new destination, if the message is of the right type. If this lookup
fails, or if the message should not be subject to a second lookup, the
already existing tipc_msg_reverse() is called. This function performs
prepares the message for rejection, if applicable.

Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 22 insertions, 18 deletions

diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index 1d98bfcda6f6..e14b2aedb212 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -1739,7 +1739,7 @@ static int filter_rcv(struct sock *sk, struct sk_buff **skb)
  * @sk: socket
  * @skb: message
  *
- * Caller must hold socket lock, but not port lock.
+ * Caller must hold socket lock
  *
  * Returns 0
  */
@@ -1805,27 +1805,31 @@ int tipc_sk_rcv(struct net *net, struct sk_buff *skb)
 	struct tipc_net *tn;
 	struct sock *sk;
 	u32 dport = msg_destport(buf_msg(skb));
-	int err;
+	int err = -TIPC_ERR_NO_PORT;
 	u32 dnode;
 
-	/* Validate destination and message */
+	/* Find destination */
 	tsk = tipc_sk_lookup(net, dport);
-	if (unlikely(!tsk)) {
-		err = tipc_msg_eval(net, skb, &dnode);
-		goto exit;
-	}
-	sk = &tsk->sk;
-
-	spin_lock_bh(&sk->sk_lock.slock);
-	err = tipc_sk_enqueue_skb(sk, &skb);
-	spin_unlock_bh(&sk->sk_lock.slock);
-	sock_put(sk);
-exit:
-	if (unlikely(skb)) {
-		tn = net_generic(net, tipc_net_id);
-		if (!err || tipc_msg_reverse(tn->own_addr, skb, &dnode, -err))
-			tipc_link_xmit_skb(net, skb, dnode, 0);
+	if (likely(tsk)) {
+		sk = &tsk->sk;
+		spin_lock_bh(&sk->sk_lock.slock);
+		err = tipc_sk_enqueue_skb(sk, &skb);
+		spin_unlock_bh(&sk->sk_lock.slock);
+		sock_put(sk);
 	}
+	if (likely(!skb))
+		return 0;
+	if (tipc_msg_lookup_dest(net, skb, &dnode, &err))
+		goto xmit;
+	if (!err) {
+		dnode = msg_destnode(buf_msg(skb));
+		goto xmit;
+	}
+	tn = net_generic(net, tipc_net_id);
+	if (!tipc_msg_reverse(tn->own_addr, skb, &dnode, -err))
+		return -EHOSTUNREACH;
+xmit:
+	tipc_link_xmit_skb(net, skb, dnode, dport);
 	return err ? -EHOSTUNREACH : 0;
 }