diff options
author | Paolo Abeni | 2022-09-30 08:59:32 -0700 |
---|---|---|
committer | David S. Miller | 2022-10-03 11:18:53 +0100 |
commit | d21f8348551831efd917528afc545832a372426e (patch) | |
tree | aa514dfc2f09d1c76b4bcd1457b24069808afc69 /net/mptcp | |
parent | 69800e516e968fa1cf9202b872dc86515eeeebe6 (diff) |
mptcp: use fastclose on more edge scenarios
Daire reported a user-space application hang-up when the
peer is forcibly closed before the data transfer completion.
The relevant application expects the peer to either
do an application-level clean shutdown or a transport-level
connection reset.
We can accommodate a such user by extending the fastclose
usage: at fd close time, if the msk socket has some unread
data, and at FIN_WAIT timeout.
Note that at MPTCP close time we must ensure that the TCP
subflows will reset: set the linger socket option to a suitable
value.
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/mptcp')
-rw-r--r-- | net/mptcp/protocol.c | 63 |
1 files changed, 44 insertions, 19 deletions
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index cad0346c9281..acf44075ba40 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -2313,8 +2313,14 @@ 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) { + /* be sure to force the tcp_disconnect() path, + * to generate the egress reset + */ + ssk->sk_lingertime = 0; + sock_set_flag(ssk, SOCK_LINGER); subflow->send_fastclose = 1; + } need_push = (flags & MPTCP_CF_PUSH) && __mptcp_retransmit_pending_data(sk); if (!dispose_it) { @@ -2577,6 +2583,16 @@ static void mptcp_mp_fail_no_response(struct mptcp_sock *msk) mptcp_reset_timeout(msk, 0); } +static void mptcp_do_fastclose(struct sock *sk) +{ + struct mptcp_subflow_context *subflow, *tmp; + struct mptcp_sock *msk = mptcp_sk(sk); + + mptcp_for_each_subflow_safe(msk, subflow, tmp) + __mptcp_close_ssk(sk, mptcp_subflow_tcp_sock(subflow), + subflow, MPTCP_CF_FASTCLOSE); +} + static void mptcp_worker(struct work_struct *work) { struct mptcp_sock *msk = container_of(work, struct mptcp_sock, work); @@ -2605,11 +2621,15 @@ static void mptcp_worker(struct work_struct *work) * closed, but we need the msk around to reply to incoming DATA_FIN, * even if it is orphaned and in FIN_WAIT2 state */ - if (sock_flag(sk, SOCK_DEAD) && - (mptcp_check_close_timeout(sk) || sk->sk_state == TCP_CLOSE)) { - inet_sk_state_store(sk, TCP_CLOSE); - __mptcp_destroy_sock(sk); - goto unlock; + if (sock_flag(sk, SOCK_DEAD)) { + if (mptcp_check_close_timeout(sk)) { + inet_sk_state_store(sk, TCP_CLOSE); + mptcp_do_fastclose(sk); + } + if (sk->sk_state == TCP_CLOSE) { + __mptcp_destroy_sock(sk); + goto unlock; + } } if (test_and_clear_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags)) @@ -2850,6 +2870,18 @@ static void __mptcp_destroy_sock(struct sock *sk) sock_put(sk); } +static __poll_t mptcp_check_readable(struct mptcp_sock *msk) +{ + /* Concurrent splices from sk_receive_queue into receive_queue will + * always show at least one non-empty queue when checked in this order. + */ + if (skb_queue_empty_lockless(&((struct sock *)msk)->sk_receive_queue) && + skb_queue_empty_lockless(&msk->receive_queue)) + return 0; + + return EPOLLIN | EPOLLRDNORM; +} + bool __mptcp_close(struct sock *sk, long timeout) { struct mptcp_subflow_context *subflow; @@ -2863,8 +2895,13 @@ bool __mptcp_close(struct sock *sk, long timeout) goto cleanup; } - if (mptcp_close_state(sk)) + if (mptcp_check_readable(msk)) { + /* the msk has read data, do the MPTCP equivalent of TCP reset */ + inet_sk_state_store(sk, TCP_CLOSE); + mptcp_do_fastclose(sk); + } else if (mptcp_close_state(sk)) { __mptcp_wr_shutdown(sk); + } sk_stream_wait_close(sk, timeout); @@ -3681,18 +3718,6 @@ static int mptcp_stream_accept(struct socket *sock, struct socket *newsock, return err; } -static __poll_t mptcp_check_readable(struct mptcp_sock *msk) -{ - /* Concurrent splices from sk_receive_queue into receive_queue will - * always show at least one non-empty queue when checked in this order. - */ - if (skb_queue_empty_lockless(&((struct sock *)msk)->sk_receive_queue) && - skb_queue_empty_lockless(&msk->receive_queue)) - return 0; - - return EPOLLIN | EPOLLRDNORM; -} - static __poll_t mptcp_check_writeable(struct mptcp_sock *msk) { struct sock *sk = (struct sock *)msk; |