socket: restore per-connection lport override over global default

OpenVPN 2.7.x introduced a regression where --lport specified
inside a <connection> block did not override a globally defined
local port. As a result, the socket was bound to the global
default port instead of the per-connection value.

Adjust the socket local_port selection logic to honour
local_port_defined when set for the active connection profile.

This change restores the documented and previously working
behaviour from 2.6.x, where connection-level lport takes
precedence over global defaults.

Github: OpenVPN#995

Change-Id: I7cf5d5ef7e2531f397ad97baf4663e3763072f6b
Signed-off-by: Gianmarco De Gregori <gianmarco@mandelbit.com>

Author: itsGiaan

src/openvpn/socket.c

@@ -1347,7 +1347,9 @@ link_socket_init_phase1(struct context *c, int sock_index, int mode)
     ASSERT(sock);
 
     const char *host = o->ce.local_list->array[sock_index]->local;
-    const char *port = o->ce.local_list->array[sock_index]->port;
+    const char *port = (o->mode == MODE_POINT_TO_POINT && o->ce.local_port_defined)
+                           ? o->ce.local_port
+                           : o->ce.local_list->array[sock_index]->port;
     int proto = o->ce.local_list->array[sock_index]->proto;
     const char *remote_host = o->ce.remote;
     const char *remote_port = o->ce.remote_port;