[RFC,mptcp-next,v9,3/6] mptcp: reuse tcp_sendmsg_fastopen()

Commit Message

Dmytro Shytyi Sept. 21, 2022, 12:55 p.m. UTC

In the following patches we will reuse modified tcp_sendmsg_fastopen().
We call it from mptcp_sendmsg().

Signed-off-by: Dmytro Shytyi <[e-mail]>
---
 include/net/tcp.h    |  3 +++
 net/ipv4/tcp.c       | 24 +++++++++++++++++++-----
 net/mptcp/protocol.c | 29 +++++++++++++++++++++++++++--
 3 files changed, 49 insertions(+), 7 deletions(-)

Patch

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 735e957f7f4b..a7d49e42470a 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1754,6 +1754,9 @@  struct sock *tcp_try_fastopen(struct sock *sk, struct sk_buff *skb,
 			      struct request_sock *req,
 			      struct tcp_fastopen_cookie *foc,
 			      const struct dst_entry *dst);
+int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
+			 int *copied, size_t size,
+			 struct ubuf_info *uarg);
 void tcp_fastopen_init_key_once(struct net *net);
 bool tcp_fastopen_cookie_check(struct sock *sk, u16 *mss,
 			     struct tcp_fastopen_cookie *cookie);
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 9251c99d3cfd..41fa9e840e0e 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -280,6 +280,9 @@ 
 #include <asm/ioctls.h>
 #include <net/busy_poll.h>
 
+#include <net/mptcp.h>
+#include "../mptcp/protocol.h"
+
 /* Track pending CMSGs. */
 enum {
 	TCP_CMSG_INQ = 1,
@@ -1162,9 +1165,9 @@  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);
@@ -1197,8 +1200,19 @@  static int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
 		}
 	}
 	flags = (msg->msg_flags & MSG_DONTWAIT) ? O_NONBLOCK : 0;
-	err = __inet_stream_connect(sk->sk_socket, uaddr,
-				    msg->msg_namelen, flags, 1);
+	if (!sk_is_mptcp(sk)) {
+		err = __inet_stream_connect(sk->sk_socket, uaddr,
+					    msg->msg_namelen, flags, 1);
+	} else {
+		struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+
+		release_sock(sk);
+		release_sock(subflow->conn);
+		err = mptcp_stream_connect(sk->sk_socket, uaddr,
+					   msg->msg_namelen, msg->msg_flags);
+		lock_sock(subflow->conn);
+		lock_sock(sk);
+	}
 	/* fastopen_req could already be freed in __inet_stream_connect
 	 * if the connection times out or gets rst
 	 */
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 470045793181..d5c502d141b4 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -1668,14 +1668,39 @@  static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 {
 	struct mptcp_sock *msk = mptcp_sk(sk);
 	struct page_frag *pfrag;
+	struct socket *ssock;
 	size_t copied = 0;
 	int ret = 0;
 	long timeo;
 
+	lock_sock(sk);
+
+	ssock = __mptcp_nmpc_socket(msk);
+
+	if (ssock && inet_sk(ssock->sk)->defer_connect) {
+		release_sock(sk);
+		goto fastopen;
+	} else {
+		release_sock(sk);
+	}
 	/* we don't support FASTOPEN yet */
-	if (msg->msg_flags & MSG_FASTOPEN)
-		return -EOPNOTSUPP;
+	if (msg->msg_flags & MSG_FASTOPEN) {
+fastopen:
+		lock_sock(sk);
+
+		ssock = __mptcp_nmpc_socket(msk);
+
+		lock_sock(ssock->sk);
 
+		if (ssock) {
+			int copied_syn_fastopen = 0;
+
+			ret = tcp_sendmsg_fastopen(ssock->sk, msg, &copied_syn_fastopen, len, NULL);
+			copied += copied_syn_fastopen;
+		}
+		release_sock(ssock->sk);
+		release_sock(sk);
+	}
 	/* silently ignore everything else */
 	msg->msg_flags &= MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL;