From: Geliang Tang <tanggeliang@kylinos.cn>

This patch adds MPTCP TLS setsockopt support. It allows setting the TCP_ULP
option to 'tls' exclusively, and enables configuration of the TLS_TX and
TLS_RX options at the SOL_TLS level.

This option cannot be set when the socket is in CLOSE or LISTEN state.

Co-developed-by: Gang Yan <yangang@kylinos.cn>
Signed-off-by: Gang Yan <yangang@kylinos.cn>
Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
---
 net/mptcp/sockopt.c | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
index a6230f7910fd..c0c95c405b43 100644
--- a/net/mptcp/sockopt.c
+++ b/net/mptcp/sockopt.c
@@ -12,6 +12,7 @@
 #include <net/protocol.h>
 #include <net/tcp.h>
 #include <net/mptcp.h>
+#include <net/tls.h>
 #include "protocol.h"
 
 #define MIN_INFO_OPTLEN_SIZE		16
@@ -567,6 +568,7 @@ static bool mptcp_supported_sockopt(int level, int optname)
 		case TCP_FASTOPEN_CONNECT:
 		case TCP_FASTOPEN_KEY:
 		case TCP_FASTOPEN_NO_COOKIE:
+		case TCP_ULP:
 			return true;
 		}
 
@@ -576,6 +578,13 @@ static bool mptcp_supported_sockopt(int level, int optname)
 		 * TCP_REPAIR_WINDOW are not supported, better avoid this mess
 		 */
 	}
+	if (level == SOL_TLS) {
+		switch (optname) {
+		case TLS_TX:
+		case TLS_RX:
+			return true;
+		}
+	}
 	return false;
 }
 
@@ -815,6 +824,19 @@ static int mptcp_setsockopt_all_sf(struct mptcp_sock *msk, int level,
 	return ret;
 }
 
+static int mptcp_setsockopt_tcp_ulp(struct sock *sk, sockptr_t optval, unsigned int optlen)
+{
+	char ulp[4] = "";
+
+	if (copy_from_user(ulp, optval.user, 4))
+		return -EFAULT;
+	if (strcmp(ulp, "tls\0"))
+		return -EOPNOTSUPP;
+	if ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))
+		return -ENOTCONN;
+	return tcp_sock_set_ulp(sk, optval, optlen);
+}
+
 static int mptcp_setsockopt_sol_tcp(struct mptcp_sock *msk, int optname,
 				    sockptr_t optval, unsigned int optlen)
 {
@@ -823,7 +845,7 @@ static int mptcp_setsockopt_sol_tcp(struct mptcp_sock *msk, int optname,
 
 	switch (optname) {
 	case TCP_ULP:
-		return -EOPNOTSUPP;
+		return mptcp_setsockopt_tcp_ulp(sk, optval, optlen);
 	case TCP_CONGESTION:
 		return mptcp_setsockopt_sol_tcp_congestion(msk, optval, optlen);
 	case TCP_DEFER_ACCEPT:
-- 
2.51.0