Stop NAT detectors before service callbacks and verify STUN restart isolation

src/utun_instance.c

@@ -409,6 +409,8 @@ void utun_instance_destroy(struct UTUN_INSTANCE *instance) {
     instance->running = 0;
     stun_nat_destroy(instance);
     stun_nat_forget_ports(instance);
+    /* Оба детектора остановить до callbacks закрываемых сервисов и транспорта. */
+    if (instance->nat_det) { nat_detection_destroy(instance->nat_det); instance->nat_det = NULL; }
     etcp_padding_stop(&instance->padding);
     DEBUG_INFO(DEBUG_CATEGORY_SYS, "[DESTROY] A done — diagnose complete");
 
@@ -433,9 +435,6 @@ void utun_instance_destroy(struct UTUN_INSTANCE *instance) {
     auto_socket_destroy(instance);
     DEBUG_INFO(DEBUG_CATEGORY_SYS, "[DESTROY] E done — socket_monitor+auto_socket");
 
-    /* Детектор владеет таймерами и вспомогательными сокетами: остановить до групп/транспорта. */
-    if (instance->nat_det) { nat_detection_destroy(instance->nat_det); instance->nat_det = NULL; }
-
     /* Phase F: BGP */
     if (instance->topo_groups) {
         etcp_router_unbind(instance, ETCP_RT_ID_CONN_MGR);

tests/test_stun_nat.c

@@ -334,6 +334,11 @@ static void test_groups(void) {
     assert(!stun_nat_get_socket_result(&f.inst, &f.source, &first));
     assert(second.key.address[3] == 5 && first.key.address[3] == 1 && second.evidence_id != first.evidence_id);
     socket_close_wrapper(duplicate.fd); f.source.next = NULL; f.original = f.source;
+    first = wait_result(&f); stun_nat_destroy(&f.inst);
+    assert(f.inst.stun_port_history && !stun_nat_init(&f.inst));
+    second = wait_result(&f);
+    assert(second.generation != first.generation);
+    assert(((const struct sockaddr_in*)&second.local)->sin_port != ((const struct sockaddr_in*)&first.local)->sin_port);
     fixture_destroy(&f);
     DEBUG_INFO(DEBUG_CATEGORY_NAT, "PASS STUN groups: duplicate ports, representative removal, separate netif, policy conflict");
 }