2023-08-03 17:13:04

by Matthieu Baerts

[permalink] [raw]
Subject: [PATCH net 3/4] mptcp: avoid bogus reset on fallback close

From: Paolo Abeni <[email protected]>

Since the blamed commit, the MPTCP protocol unconditionally sends
TCP resets on all the subflows on disconnect().

That fits full-blown MPTCP sockets - to implement the fastclose
mechanism - but causes unexpected corruption of the data stream,
caught as sporadic self-tests failures.

Fixes: d21f83485518 ("mptcp: use fastclose on more edge scenarios")
Cc: [email protected]
Tested-by: Matthieu Baerts <[email protected]>
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/419
Signed-off-by: Paolo Abeni <[email protected]>
Reviewed-by: Matthieu Baerts <[email protected]>
Signed-off-by: Matthieu Baerts <[email protected]>
---
net/mptcp/protocol.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 3317d1cca156..ac7c11a5cbe5 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -2335,7 +2335,7 @@ static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,

lock_sock_nested(ssk, SINGLE_DEPTH_NESTING);

- if (flags & MPTCP_CF_FASTCLOSE) {
+ if ((flags & MPTCP_CF_FASTCLOSE) && !__mptcp_check_fallback(msk)) {
/* be sure to force the tcp_disconnect() path,
* to generate the egress reset
*/

--
2.40.1