[RFC PATCH mptcp-next v15 1/5] mptcp: introduce MSG_FASTOPEN flag

[Dmytro Shytyi <dmytro@shytyi.net>]

In the following patches we will analyse the MSG_FASTOPEN flag
in the mptcp_sendmsg() and invoke the MPTFO.

Signed-of-by: Benjamin Hesmans <benjamin.hesmans@tessares.net>
Signed-off-by: Dmytro Shytyi <dmytro@shytyi.net>
---
 net/mptcp/protocol.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 3196d2a350f9..f4247218fd1b 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -1704,17 +1704,14 @@ static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	int ret = 0;
 	long timeo;
 
-	/* we don't support FASTOPEN yet */
-	if (msg->msg_flags & MSG_FASTOPEN)
-		return -EOPNOTSUPP;
-
 	/* silently ignore everything else */
-	msg->msg_flags &= MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL;
+	msg->msg_flags &= MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL | MSG_FASTOPEN;
 
 	lock_sock(sk);
 
 	ssock = __mptcp_nmpc_socket(msk);
-	if (unlikely(ssock && inet_sk(ssock->sk)->defer_connect)) {
+	if (unlikely(ssock && (inet_sk(ssock->sk)->defer_connect ||
+			       msg->msg_flags & MSG_FASTOPEN))) {
 		int copied_syn = 0;
 
 		ret = mptcp_sendmsg_fastopen(sk, ssock->sk, msg, len, &copied_syn);
-- 
2.34.1