3 files changed, 22 insertions, 5 deletions

diff --git a/net/tipc/msg.h b/net/tipc/msg.h
index a4e944d59394..cd64d7b2a0fe 100644
--- a/net/tipc/msg.h
+++ b/net/tipc/msg.h
@@ -216,6 +216,16 @@ static inline void msg_set_non_seq(struct tipc_msg *m, u32 n)
         msg_set_bits(m, 0, 20, 1, n);
 }
 
+static inline int msg_is_syn(struct tipc_msg *m)
+{
+        return msg_bits(m, 0, 17, 1);
+}
+
+static inline void msg_set_syn(struct tipc_msg *m, u32 d)
+{
+        msg_set_bits(m, 0, 17, 1, d);
+}
+
 static inline int msg_dest_droppable(struct tipc_msg *m)
 {
         return msg_bits(m, 0, 19, 1);
diff --git a/net/tipc/node.h b/net/tipc/node.h
index 48b3298a248d..03f5efb62cfb 100644
--- a/net/tipc/node.h
+++ b/net/tipc/node.h
@@ -45,6 +45,7 @@
 /* Optional capabilities supported by this code version
  */
 enum {
+        TIPC_SYN_BIT          = (1),
         TIPC_BCAST_SYNCH      = (1 << 1),
         TIPC_BCAST_STATE_NACK = (1 << 2),
         TIPC_BLOCK_FLOWCTL    = (1 << 3),
@@ -53,11 +54,12 @@ enum {
         TIPC_LINK_PROTO_SEQNO = (1 << 6)
 };
 
-#define TIPC_NODE_CAPABILITIES (TIPC_BCAST_SYNCH       |  \
-                                TIPC_BCAST_STATE_NACK  |  \
-                                TIPC_BCAST_RCAST       |  \
-                                TIPC_BLOCK_FLOWCTL     |  \
-                                TIPC_NODE_ID128        |  \
+#define TIPC_NODE_CAPABILITIES (TIPC_SYN_BIT           |  \
+                                TIPC_BCAST_SYNCH       |   \
+                                TIPC_BCAST_STATE_NACK  |   \
+                                TIPC_BCAST_RCAST       |   \
+                                TIPC_BLOCK_FLOWCTL     |   \
+                                TIPC_NODE_ID128        |   \
                                 TIPC_LINK_PROTO_SEQNO)
 #define INVALID_BEARER_ID -1
 
diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index 094cfdc1e2b6..89d6dc0f456d 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -1319,6 +1319,7 @@ static int __tipc_sendmsg(struct socket *sock, struct msghdr *m, size_t dlen)
                         tsk->conn_type = dest->addr.name.name.type;
                         tsk->conn_instance = dest->addr.name.name.instance;
                 }
+                msg_set_syn(hdr, 1);
         }
 
         seq = &dest->addr.nameseq;
@@ -1478,6 +1479,7 @@ static void tipc_sk_finish_conn(struct tipc_sock *tsk, u32 peer_port,
         struct net *net = sock_net(sk);
         struct tipc_msg *msg = &tsk->phdr;
 
+        msg_set_syn(msg, 0);
         msg_set_destnode(msg, peer_node);
         msg_set_destport(msg, peer_port);
         msg_set_type(msg, TIPC_CONN_MSG);
@@ -2006,6 +2008,9 @@ static bool tipc_sk_filter_connect(struct tipc_sock *tsk, struct sk_buff *skb)
                 return false;
         case TIPC_LISTEN:
                 /* Accept only SYN message */
+                if (!msg_is_syn(hdr) &&
+                    tipc_node_get_capabilities(net, onode) & TIPC_SYN_BIT)
+                        return false;
                 if (!con_msg && !err)
                         return true;
                 return false;