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| author | Paolo Abeni <pabeni@redhat.com> | 2020-11-16 12:48:09 +0300 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2020-11-16 21:46:07 +0300 |
| commit | e16163b6e2b720fb74e5af758546f6dad27e6c9e (patch) | |
| tree | 85e5123bc59744f1fd1a3110f5b517b5baa5f356 /net/mptcp/pm_netlink.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/pm_netlink.c')
| -rw-r--r-- | net/mptcp/pm_netlink.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c index 446ef8f07734..f8a9d82a0ea8 100644 --- a/net/mptcp/pm_netlink.c +++ b/net/mptcp/pm_netlink.c @@ -416,14 +416,13 @@ void mptcp_pm_nl_rm_addr_received(struct mptcp_sock *msk) list_for_each_entry_safe(subflow, tmp, &msk->conn_list, node) { struct sock *ssk = mptcp_subflow_tcp_sock(subflow); int how = RCV_SHUTDOWN | SEND_SHUTDOWN; - long timeout = 0; if (msk->pm.rm_id != subflow->remote_id) continue; spin_unlock_bh(&msk->pm.lock); mptcp_subflow_shutdown(sk, ssk, how); - __mptcp_close_ssk(sk, ssk, subflow, timeout); + __mptcp_close_ssk(sk, ssk, subflow); spin_lock_bh(&msk->pm.lock); msk->pm.add_addr_accepted--; @@ -452,14 +451,13 @@ void mptcp_pm_nl_rm_subflow_received(struct mptcp_sock *msk, u8 rm_id) list_for_each_entry_safe(subflow, tmp, &msk->conn_list, node) { struct sock *ssk = mptcp_subflow_tcp_sock(subflow); int how = RCV_SHUTDOWN | SEND_SHUTDOWN; - long timeout = 0; if (rm_id != subflow->local_id) continue; spin_unlock_bh(&msk->pm.lock); mptcp_subflow_shutdown(sk, ssk, how); - __mptcp_close_ssk(sk, ssk, subflow, timeout); + __mptcp_close_ssk(sk, ssk, subflow); spin_lock_bh(&msk->pm.lock); msk->pm.local_addr_used--; |