Merge branch 'mptcp-mptcp-support-for-tcp_fastopen_connect'

Mat Martineau says:

====================
mptcp: MPTCP support for TCP_FASTOPEN_CONNECT

RFC 8684 appendix B describes how to use TCP Fast Open with MPTCP. This
series allows TFO use with MPTCP using the TCP_FASTOPEN_CONNECT socket
option. The scope here is limited to the initiator of the connection -
support for MSG_FASTOPEN and the listener side of the connection will be
in a separate series. The preexisting TCP fastopen code does most of the
work, so these changes mostly involve plumbing MPTCP through to those
TCP functions.

Patch 1 changes the MPTCP socket option code to pass the
TCP_FASTOPEN_CONNECT option through to the initial unconnected subflow.

Patch 2 exports the existing tcp_sendmsg_fastopen() function from tcp.c

Patch 3 adds the call to tcp_sendmsg_fastopen() from the MPTCP send
function.

Patch 4 modifies mptcp_poll() to handle the deferred TFO connection.
====================

Link: https://lore.kernel.org/r/20220926232739.76317-1-mathew.j.martineau@linux.intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 2 insertions, 3 deletions

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index a109a4cb1e47..648b5c54bb32 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1162,9 +1162,8 @@ void tcp_free_fastopen_req(struct tcp_sock *tp)
 	}
 }
 
-static int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
-				int *copied, size_t size,
-				struct ubuf_info *uarg)
+int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg, int *copied,
+			 size_t size, struct ubuf_info *uarg)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
 	struct inet_sock *inet = inet_sk(sk);