Networking: Start the network monitor for a socket when a TCP socket is dup'ed.

net/socket/socket.h

@@ -354,5 +354,24 @@ int net_timeo(systime_t start_time, socktimeo_t timeo);
 ssize_t psock_send(FAR struct socket *psock, FAR const void *buf, size_t len,
                    int flags);
 
+/****************************************************************************
+ * Name: net_clone
+ *
+ * Description:
+ *   Performs the low level, common portion of net_dupsd() and net_dupsd2()
+ *
+ * Input Parameters:
+ *   psock1 - The existing socket that is being cloned.
+ *   psock2 - A reference to an uninitialized socket structure alloated by
+ *            the caller.
+ *
+ * Returned Value:
+ *   Zero (OK) is returned on success; a negated errno value is returned on
+ *   any failure.
+ *
+ ****************************************************************************/
+
+int net_clone(FAR struct socket *psock1, FAR struct socket *psock2);
+
 #endif /* CONFIG_NET */
 #endif /* _NET_SOCKET_SOCKET_H */