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author | Paolo Abeni <pabeni@redhat.com> | 2020-11-16 12:48:09 +0300 |
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committer | Jakub Kicinski <kuba@kernel.org> | 2020-11-16 21:46:07 +0300 |
commit | e16163b6e2b720fb74e5af758546f6dad27e6c9e (patch) | |
tree | 85e5123bc59744f1fd1a3110f5b517b5baa5f356 /net/mptcp/options.c | |
parent | eaa2ffabfc35580da3fb1d31897fb696c514ea7a (diff) | |
download | linux-e16163b6e2b720fb74e5af758546f6dad27e6c9e.tar.xz |
mptcp: refactor shutdown and close
We must not close the subflows before all the MPTCP level
data, comprising the DATA_FIN has been acked at the MPTCP
level, otherwise we could be unable to retransmit as needed.
__mptcp_wr_shutdown() shutdown is responsible to check for the
correct status and close all subflows. Is called by the output
path after spooling any data and at shutdown/close time.
In a similar way, __mptcp_destroy_sock() is responsible to clean-up
the MPTCP level status, and is called when the msk transition
to TCP_CLOSE.
The protocol level close() does not force anymore the TCP_CLOSE
status, but orphan the msk socket and all the subflows.
Orphaned msk sockets are forciby closed after a timeout or
when all MPTCP-level data is acked.
There is a caveat about keeping the orphaned subflows around:
the TCP stack can asynchronusly call tcp_cleanup_ulp() on them via
tcp_close(). To prevent accessing freed memory on later MPTCP
level operations, the msk acquires a reference to each subflow
socket and prevent subflow_ulp_release() from releasing the
subflow context before __mptcp_destroy_sock().
The additional subflow references are released by __mptcp_done()
and the async ULP release is detected checking ULP ops. If such
field has been already cleared by the ULP release path, the
dangling context is freed directly by __mptcp_done().
Co-developed-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/mptcp/options.c')
-rw-r--r-- | net/mptcp/options.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/net/mptcp/options.c b/net/mptcp/options.c index a6b57021b6d0..1be272d2bd95 100644 --- a/net/mptcp/options.c +++ b/net/mptcp/options.c @@ -492,7 +492,7 @@ static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb, bool ret = false; mpext = skb ? mptcp_get_ext(skb) : NULL; - snd_data_fin_enable = READ_ONCE(msk->snd_data_fin_enable); + snd_data_fin_enable = mptcp_data_fin_enabled(msk); if (!skb || (mpext && mpext->use_map) || snd_data_fin_enable) { unsigned int map_size; |