add debug messages to nat traversal

kamailio/nat-traversal-role.cfg

@@ -92,21 +92,29 @@ route[NAT_MANAGE]
    }
 
    if ( is_request() && isflagset(FLAG_INTERNALLY_SOURCED)) {
+        xlog("L_DEBUG", "$ci|log|INTERNAL AND REQUEST => SET FLB_NATB\n");
         setbflag(FLB_NATB);
    }
 
    if ( is_request() && has_totag() ) {
+        xlog("L_DEBUG", "$ci|log|TOTAG AND REQUEST => SET FLB_NATB\n");
         setbflag(FLB_NATB);
    }
 
    if (!(isflagset(FLT_NATS) || isbflagset(FLB_NATB))) {
+        xlog("L_DEBUG", "$ci|log|NOT SETTING\n");
         return;
    }
 
    if (is_reply()) {
        if(isflagset(FLT_NATS) || isbflagset(FLB_NATB)) {
            if(is_first_hop()) {
-               set_contact_alias();
+               if (!isflagset(FLAG_MANUAL_ALIAS)) {
+                   xlog("L_DEBUG", "$ci|log|MANAGE => SET CONTACT ALIAS\n");
+                   set_contact_alias();
+               }
+           } else {
+               xlog("L_DEBUG", "$ci|log|MANAGE => NOT FIRST HOP $mb\n");
            }
        }
    }