From: Paolo Abeni pabeni@redhat.com
commit d4e85922e3e7ef2071f91f65e61629b60f3a9cf4 upstream.
If the peer closes all the existing subflows for a given mptcp socket and later the application closes it, the current implementation let it survive until the timewait timeout expires.
While the above is allowed by the protocol specification it consumes resources for almost no reason and additionally causes sporadic self-tests failures.
Let's move the mptcp socket to the TCP_CLOSE state when there are no alive subflows at close time, so that the allocated resources will be freed immediately.
Fixes: e16163b6e2b7 ("mptcp: refactor shutdown and close") Cc: stable@vger.kernel.org Signed-off-by: Paolo Abeni pabeni@redhat.com Reviewed-by: Matthieu Baerts matthieu.baerts@tessares.net Signed-off-by: Matthieu Baerts matthieu.baerts@tessares.net Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/mptcp/protocol.c | 9 +++++++++ 1 file changed, 9 insertions(+)
--- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -2908,6 +2908,7 @@ bool __mptcp_close(struct sock *sk, long struct mptcp_subflow_context *subflow; struct mptcp_sock *msk = mptcp_sk(sk); bool do_cancel_work = false; + int subflows_alive = 0;
sk->sk_shutdown = SHUTDOWN_MASK;
@@ -2933,6 +2934,8 @@ cleanup: struct sock *ssk = mptcp_subflow_tcp_sock(subflow); bool slow = lock_sock_fast_nested(ssk);
+ subflows_alive += ssk->sk_state != TCP_CLOSE; + /* since the close timeout takes precedence on the fail one, * cancel the latter */ @@ -2948,6 +2951,12 @@ cleanup: } sock_orphan(sk);
+ /* all the subflows are closed, only timeout can change the msk + * state, let's not keep resources busy for no reasons + */ + if (subflows_alive == 0) + inet_sk_state_store(sk, TCP_CLOSE); + sock_hold(sk); pr_debug("msk=%p state=%d", sk, sk->sk_state); if (mptcp_sk(sk)->token)