tipc: fix flow control accounting for implicit connect

[ Upstream commit 92ef12b3 ]

In the case of implicit connect message with data > 1K, the flow
control accounting is incorrect. At this state, the socket does not
know the peer nodes capability and falls back to legacy flow control
by return 1, however the receiver of this message will perform the
new block accounting. This leads to a slack and eventually traffic
disturbance.

In this commit, we perform tipc_node_get_capabilities() at implicit
connect and perform accounting based on the peer's capability.
Signed-off-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

net/tipc/socket.c

@@ -1063,8 +1063,10 @@ static int __tipc_sendstream(struct socket *sock, struct msghdr *m, size_t dlen)
 	/* Handle implicit connection setup */
 	if (unlikely(dest)) {
 		rc = __tipc_sendmsg(sock, m, dlen);
-		if (dlen && (dlen == rc))
+		if (dlen && dlen == rc) {
+			tsk->peer_caps = tipc_node_get_capabilities(net, dnode);
 			tsk->snt_unacked = tsk_inc(tsk, dlen + msg_hdr_sz(hdr));
+		}
 		return rc;
 	}