[net 1/1] tipc: fix flow control accounting for implicit connect

[net 1/1] tipc: fix flow control accounting for implicit connect

[Jon Maloy]

From: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com>

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>
---
 net/tipc/socket.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index 3f03ddd..b6f99b0 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -1419,8 +1419,10 @@ 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;
 	}
 
-- 
2.1.4

Re: [net 1/1] tipc: fix flow control accounting for implicit connect

[David Miller]

From: Jon Maloy <jon.maloy@ericsson.com>
Date: Tue, 25 Sep 2018 18:21:58 +0200

> From: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com>
> 
> 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>

Applied and queued up for -stable, thank you.