Add independent STUN NAT probes with RFC 5780 discovery

src/utun_instance.c

@@ -11,6 +11,7 @@
 #include "topo_group.h"
 #include "topo_group_invite.h"
 #include "nat_detection.h"
+#include "transport_layer/stun_nat.h"
 #include "etcp_connections.h"
 #include "etcp.h"
 #include "conn_mgr.h"
@@ -404,6 +405,7 @@ void utun_instance_destroy(struct UTUN_INSTANCE *instance) {
     if (instance->ua) uasync_print_resources(instance->ua, "INSTANCE_DESTROY_BEFORE");
     
     instance->running = 0;
+    stun_nat_destroy(instance);
     etcp_padding_stop(&instance->padding);
     DEBUG_INFO(DEBUG_CATEGORY_SYS, "[DESTROY] A done — diagnose complete");
 
@@ -702,6 +704,7 @@ int utun_core_start(struct UTUN_INSTANCE *instance) {
     radio_init_instance(instance);
 
     instance->core_started = 1;
+    if (stun_nat_init(instance) < 0) DEBUG_WARN(DEBUG_CATEGORY_NAT, "STUN diagnostics could not start; core remains operational");
     DEBUG_INFO(DEBUG_CATEGORY_SYS, "core started");
     return 0;
 }
@@ -1076,8 +1079,10 @@ struct UTUN_INSTANCE *utun_instance_reload(struct UTUN_INSTANCE *instance, struc
     fw_load_rules(&instance->fw, &new_config->global);
     // routing_destroy(instance);  // commented per request - BGP self-restarts on conn events
     // routing_create(instance);   // commented per request
+    stun_nat_destroy(instance);
     if (instance->config) free_config(instance->config);
     instance->config = new_config;
+    if (instance->core_started && stun_nat_init(instance) < 0) DEBUG_WARN(DEBUG_CATEGORY_NAT, "STUN restart failed after config reload");
     if (client_result < 0) DEBUG_WARN(DEBUG_CATEGORY_CONFIG, "Reload completed with client errors; previous client handles retained");
     else DEBUG_INFO(DEBUG_CATEGORY_CONFIG, "Selective partial reload completed (only changed updated, unchanged untouched, [debug] applied)");
     return instance;