Commit 280d6543 authored by Matthieu Baerts (NGI0)'s avatar Matthieu Baerts (NGI0) Committed by Jakub Kicinski
Browse files

mptcp: avoid dup SUB_CLOSED events after disconnect 



In case of subflow disconnect(), which can also happen with the first
subflow in case of errors like timeout or reset, mptcp_subflow_ctx_reset
will reset most fields from the mptcp_subflow_context structure,
including close_event_done. Then, when another subflow is closed, yet
another SUB_CLOSED event for the disconnected initial subflow is sent.
Because of the previous reset, there are no source address and
destination port.

A solution is then to also check the subflow's local id: it shouldn't be
negative anyway.

Another solution would be not to reset subflow->close_event_done at
disconnect time, but when reused. But then, probably the whole reset
could be done when being reused. Let's not change this logic, similar
to TCP with tcp_disconnect().

Fixes: d82809b6 ("mptcp: avoid duplicated SUB_CLOSED events")
Cc: stable@vger.kernel.org
Reported-by: default avatarMarco Angaroni <marco.angaroni@italtel.com>
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/603


Reviewed-by: default avatarGeliang Tang <geliang@kernel.org>
Signed-off-by: default avatarMatthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20260127-net-mptcp-dup-nl-events-v1-1-7f71e1bc4feb@kernel.org


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 95f82b2b

net/mptcp/protocol.c

+2 −2
Original line number Diff line number Diff line
@@ -2598,8 +2598,8 @@ void mptcp_close_ssk(struct sock *sk, struct sock *ssk, 
	struct mptcp_sock *msk = mptcp_sk(sk);

	struct sk_buff *skb;



	/* The first subflow can already be closed and still in the list */

	if (subflow->close_event_done)

	/* The first subflow can already be closed or disconnected */

	if (subflow->close_event_done || READ_ONCE(subflow->local_id) < 0)

		return;



	subflow->close_event_done = true;