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: 2303f994b3e1 ("mptcp: Associate MPTCP context with TCP socket")
Signed-off-by: Paolo Abeni <pab...@redhat.com>
---
net/mptcp/protocol.c | 20 ++++++++++++++++++--
1 file changed, 18 insertions(+), 2 deletions(-)
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index c8675d2eb5b9..8959a74f707d 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -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));
- mptcp_copy_inaddrs(sock->sk, 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);
--
2.21.3
