fix: self-detection uses interface_addr instead of local_addr (works with 0.0.0.0 bind); don't overwrite nat_addr in handle_init_response_client if NAT already verified

src/etcp_connections.c

@@ -1295,14 +1295,14 @@ static void send_init_response(struct ETCP_SOCKET* e_sock, struct ETCP_DGRAM* pk
         }
     }
     /* Self-detection: if my IP is non-local, I'm on a public IP */
-    if (e_sock->nat_type != NAT_VERIFIED_DIRECT && e_sock->local_addr.ss_family == AF_INET) {
-        uint32_t my_ip = ((struct sockaddr_in*)&e_sock->local_addr)->sin_addr.s_addr;
+    if (e_sock->nat_type != NAT_VERIFIED_DIRECT && e_sock->interface_addr.ss_family == AF_INET) {
+        uint32_t my_ip = ((struct sockaddr_in*)&e_sock->interface_addr)->sin_addr.s_addr;
         if (my_ip != 0 && !is_local_subnet(my_ip)) {
             e_sock->nat_type = NAT_VERIFIED_DIRECT;
             struct sockaddr_in* nat_sin = (struct sockaddr_in*)&e_sock->nat_addr;
             nat_sin->sin_family = AF_INET;
             nat_sin->sin_addr.s_addr = my_ip;
-            nat_sin->sin_port = ((struct sockaddr_in*)&e_sock->local_addr)->sin_port;
+            nat_sin->sin_port = ((struct sockaddr_in*)&e_sock->interface_addr)->sin_port;
             if (link->etcp->instance->bgp) {
                 route_bgp_update_my_nodeinfo(link->etcp->instance->bgp->instance, link->etcp->instance->bgp);
                 struct ROUTE_BGP* bgp = link->etcp->instance->bgp;
@@ -1421,12 +1421,14 @@ static int handle_init_response_client(struct ETCP_SOCKET* e_sock, struct ETCP_D
                        link->nat_changes_count);
         }
         
-        // Update socket NAT address
+        // Update socket NAT address (only if not already verified)
         {
-            struct sockaddr_in* sin = (struct sockaddr_in*)&e_sock->nat_addr;
-            sin->sin_family = AF_INET;
-            sin->sin_addr.s_addr = new_nat_ip;
-            sin->sin_port = htons(new_nat_port);
+            if (e_sock->nat_type < NAT_VERIFIED_UNKNOWN) {
+                struct sockaddr_in* sin = (struct sockaddr_in*)&e_sock->nat_addr;
+                sin->sin_family = AF_INET;
+                sin->sin_addr.s_addr = new_nat_ip;
+                sin->sin_port = htons(new_nat_port);
+            }
         }
     } else {
         // Legacy format without NAT info