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mptcp: don't orphan ssk in mptcp_close()

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All of the subflows of a msk will be orphaned in mptcp_close(), which
means the subflows are in DEAD state. After then, DATA_FIN will be sent,
and the other side will response with a DATA_ACK for this DATA_FIN.

However, if the other side still has pending data, the data that received
on these subflows will not be passed to the msk, as they are DEAD and
subflow_data_ready() will not be called in tcp_data_ready(). Therefore,
these data can't be acked, and they will be retransmitted again and again,
until timeout.

Fix this by setting ssk->sk_socket and ssk->sk_wq to 'NULL', instead of
orphaning the subflows in __mptcp_close(), as Paolo suggested.

Fixes: e16163b6e2 ("mptcp: refactor shutdown and close")
Reviewed-by: Biao Jiang <benbjiang@tencent.com>
Reviewed-by: Mengen Sun <mengensun@tencent.com>
Signed-off-by: Menglong Dong <imagedong@tencent.com>
Reviewed-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Menglong Dong
2022-11-28 16:42:37 +01:00
committed by Jakub Kicinski
parent 39f59bca27
commit fe94800184
1 changed files with 6 additions and 7 deletions
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13
net/mptcp/protocol.c
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@@ -2354,12 +2354,7 @@ static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
goto out;
}
/* if we are invoked by the msk cleanup code, the subflow is
* already orphaned
*/
if (ssk->sk_socket)
sock_orphan(ssk);
sock_orphan(ssk);
subflow->disposable = 1;
/* if ssk hit tcp_done(), tcp_cleanup_ulp() cleared the related ops
@@ -2940,7 +2935,11 @@ cleanup:
if (ssk == msk->first)
subflow->fail_tout = 0;
sock_orphan(ssk);
/* detach from the parent socket, but allow data_ready to
* push incoming data into the mptcp stack, to properly ack it
*/
ssk->sk_socket = NULL;
ssk->sk_wq = NULL;
unlock_sock_fast(ssk, slow);
}
sock_orphan(sk);