tipc: refactor function tipc_sk_filter_connect()

We refactor the function tipc_sk_filter_connect(), both to make it
more readable and as a preparation for the next commit.

Acked-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, 43 insertions, 58 deletions

diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index 8152a8135422..094cfdc1e2b6 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -1959,91 +1959,76 @@ static void tipc_sk_proto_rcv(struct sock *sk,
 }
 
 /**
- * tipc_filter_connect - Handle incoming message for a connection-based socket
+ * tipc_sk_filter_connect - check incoming message for a connection-based socket
  * @tsk: TIPC socket
- * @skb: pointer to message buffer. Set to NULL if buffer is consumed
- *
- * Returns true if everything ok, false otherwise
+ * @skb: pointer to message buffer.
+ * Returns true if message should be added to receive queue, false otherwise
  */
 static bool tipc_sk_filter_connect(struct tipc_sock *tsk, struct sk_buff *skb)
 {
         struct sock *sk = &tsk->sk;
         struct net *net = sock_net(sk);
         struct tipc_msg *hdr = buf_msg(skb);
-        u32 pport = msg_origport(hdr);
-        u32 pnode = msg_orignode(hdr);
+        bool con_msg = msg_connected(hdr);
+        u32 pport = tsk_peer_port(tsk);
+        u32 pnode = tsk_peer_node(tsk);
+        u32 oport = msg_origport(hdr);
+        u32 onode = msg_orignode(hdr);
+        int err = msg_errcode(hdr);
 
         if (unlikely(msg_mcast(hdr)))
                 return false;
 
         switch (sk->sk_state) {
         case TIPC_CONNECTING:
-                /* Accept only ACK or NACK message */
-                if (unlikely(!msg_connected(hdr))) {
-                        if (pport != tsk_peer_port(tsk) ||
-                            pnode != tsk_peer_node(tsk))
-                                return false;
-
-                        tipc_set_sk_state(sk, TIPC_DISCONNECTING);
-                        sk->sk_err = ECONNREFUSED;
-                        sk->sk_state_change(sk);
-                        return true;
-                }
-
-                if (unlikely(msg_errcode(hdr))) {
-                        tipc_set_sk_state(sk, TIPC_DISCONNECTING);
-                        sk->sk_err = ECONNREFUSED;
-                        sk->sk_state_change(sk);
-                        return true;
-                }
-
-                if (unlikely(!msg_isdata(hdr))) {
-                        tipc_set_sk_state(sk, TIPC_DISCONNECTING);
-                        sk->sk_err = EINVAL;
-                        sk->sk_state_change(sk);
-                        return true;
+                /* Setup ACK */
+                if (likely(con_msg)) {
+                        if (err)
+                                break;
+                        tipc_sk_finish_conn(tsk, oport, onode);
+                        msg_set_importance(&tsk->phdr, msg_importance(hdr));
+                        /* ACK+ message with data is added to receive queue */
+                        if (msg_data_sz(hdr))
+                                return true;
+                        /* Empty ACK-, - wake up sleeping connect() and drop */
+                        sk->sk_data_ready(sk);
+                        msg_set_dest_droppable(hdr, 1);
+                        return false;
                 }
+                /* Ignore connectionless message if not from listening socket */
+                if (oport != pport || onode != pnode)
+                        return false;
 
-                tipc_sk_finish_conn(tsk, msg_origport(hdr), msg_orignode(hdr));
-                msg_set_importance(&tsk->phdr, msg_importance(hdr));
-
-                /* If 'ACK+' message, add to socket receive queue */
-                if (msg_data_sz(hdr))
-                        return true;
-
-                /* If empty 'ACK-' message, wake up sleeping connect() */
-                sk->sk_data_ready(sk);
-
-                /* 'ACK-' message is neither accepted nor rejected: */
-                msg_set_dest_droppable(hdr, 1);
-                return false;
-
+                /* Rejected SYN - abort */
+                break;
         case TIPC_OPEN:
         case TIPC_DISCONNECTING:
-                break;
+                return false;
         case TIPC_LISTEN:
                 /* Accept only SYN message */
-                if (!msg_connected(hdr) && !(msg_errcode(hdr)))
+                if (!con_msg && !err)
                         return true;
-                break;
+                return false;
         case TIPC_ESTABLISHED:
                 /* Accept only connection-based messages sent by peer */
-                if (unlikely(!tsk_peer_msg(tsk, hdr)))
+                if (likely(con_msg && !err && pport == oport && pnode == onode))
+                        return true;
+                if (!tsk_peer_msg(tsk, hdr))
                         return false;
-
-                if (unlikely(msg_errcode(hdr))) {
-                        tipc_set_sk_state(sk, TIPC_DISCONNECTING);
-                        /* Let timer expire on it's own */
-                        tipc_node_remove_conn(net, tsk_peer_node(tsk),
-                                              tsk->portid);
-                        sk->sk_state_change(sk);
-                }
+                if (!err)
+                        return true;
+                tipc_set_sk_state(sk, TIPC_DISCONNECTING);
+                tipc_node_remove_conn(net, pnode, tsk->portid);
+                sk->sk_state_change(sk);
                 return true;
         default:
                 pr_err("Unknown sk_state %u\n", sk->sk_state);
         }
-
-        return false;
+        /* Abort connection setup attempt */
+        tipc_set_sk_state(sk, TIPC_DISCONNECTING);
+        sk->sk_err = ECONNREFUSED;
+        sk->sk_state_change(sk);
+        return true;
 }
 
 /**