mptcp: fix unblocking connect() (41be81a8) · Commits · 戴 / test

Currently unblocking connect() on MPTCP sockets fails frequently. If mptcp_stream_connect() is invoked to complete a previously attempted unblocking connection, it will still try to create the first subflow via __mptcp_socket_create(). If the 3whs is completed and the 'can_ack' flag is already set, the latter will fail with -EINVAL. This change addresses the issue checking for pending connect and delegating the completion to the first subflow. Additionally do msk addresses and sk_state changes only when needed. Fixes: ("mptcp: Associate MPTCP context with TCP socket") Signed-off-by:

Paolo Abeni <pabeni@redhat.com> Reviewed-by:

Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/mptcp/protocol.c

+18 −2

Original line number	Diff line number	Diff line
		@@ -1712,6 +1712,14 @@ static int mptcp_stream_connect(struct socket sock, struct sockaddr uaddr,
		int err;

		lock_sock(sock->sk);
		if (sock->state != SS_UNCONNECTED && msk->subflow) {
		/* pending connection or invalid state, let existing subflow
		* cope with that
		*/
		ssock = msk->subflow;
		goto do_connect;
		}

		ssock = __mptcp_socket_create(msk, TCP_SYN_SENT);
		if (IS_ERR(ssock)) {
		err = PTR_ERR(ssock);
		@@ -1726,9 +1734,17 @@ static int mptcp_stream_connect(struct socket sock, struct sockaddr uaddr,
		mptcp_subflow_ctx(ssock->sk)->request_mptcp = 0;
		#endif

		do_connect:
		err = ssock->ops->connect(ssock, uaddr, addr_len, flags);
		inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk));
		sock->state = ssock->state;

		/* on successful connect, the msk state will be moved to established by
		* subflow_finish_connect()
		*/
		if (!err \|\| err == EINPROGRESS)
		mptcp_copy_inaddrs(sock->sk, ssock->sk);
		else
		inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk));

		unlock:
		release_sock(sock->sk);

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