Return NULL when callbacks cancel ETCP connection creation

src/transport_layer/etcp.c

@@ -250,12 +250,22 @@ struct ETCP_CONN* etcp_connection_create(struct UTUN_INSTANCE* instance, char* n
     DEBUG_DEBUG(DEBUG_CATEGORY_ETCP, "[%s] connection initialized. ETCP=%p mtu=%d, next_tx_id=%u state=pending",
                 etcp->log_name, etcp, etcp->mtu, etcp->next_tx_id);
 
-    // Вызываем callback для нового соединения если установлен
-    if (instance) {
-        struct etcp_inst_cbk_entry* cbe = instance->new_conn_cbks;
-        while (cbe) { struct etcp_inst_cbk_entry* n = cbe->next; cbe->fn(etcp, cbe->arg); cbe = n; }
+    /* Конструктор удерживает ресурсы до завершения уведомлений; отмена не возвращает закрытый объект. */
+    etcp->callbacks_running++;
+    struct etcp_inst_cbk_entry* cbe = instance->new_conn_cbks;
+    while (cbe) {
+        struct etcp_inst_cbk_entry* next = cbe->next;
+        cbe->fn(etcp, cbe->arg);
+        if (etcp->close_requested) break;
+        cbe = next;
+    }
+    if (!etcp->close_requested) etcp_fire_conn_status(etcp, ETCP_CONN_STATUS_NEW);
+    etcp->callbacks_running--;
+    if (etcp->close_requested) {
+        DEBUG_DEBUG(DEBUG_CATEGORY_ETCP, "[%s] connection creation cancelled by callback", etcp->log_name);
+        etcp_connection_close(etcp);
+        return NULL;
     }
-    etcp_fire_conn_status(etcp, ETCP_CONN_STATUS_NEW);
 
     return etcp;
 }

tests/test_etcp_lifecycle.c

@@ -142,6 +142,35 @@ static void ncd_late_up_case(struct UTUN_INSTANCE* inst) {
     CHECK(!inst->ncd_registry && !inst->connections->count);
     puts("PASS NCD late UP after timeout and subsequent reconnect");
 }
+struct create_close_case { unsigned created, published, deleted, status; };
+static void cancel_created_connection(struct ETCP_CONN *conn, void *arg) {
+    struct create_close_case *test = arg;
+    test->created++;
+    etcp_connection_close(conn);
+    CHECK(conn->close_requested && !conn->delete_complete);
+}
+static void observe_created_connection(struct ETCP_CONN *conn, int status, void *arg) {
+    struct create_close_case *test = arg;
+    if (status == ETCP_CONN_STATUS_DELETE) test->deleted++;
+    if (status != ETCP_CONN_STATUS_NEW) return;
+    test->published++;
+    if (test->status) etcp_connection_close(conn);
+}
+static void constructor_close_cases(struct UTUN_INSTANCE *inst) {
+    for (unsigned status = 0; status < 2; status++) {
+        struct create_close_case test = {.status = status};
+        if (!status) etcp_add_new_conn_cbk(inst, cancel_created_connection, &test);
+        etcp_add_conn_status_cbk(inst, observe_created_connection, &test);
+        CHECK(etcp_connection_create(inst, "cancel creation") == NULL);
+        CHECK(test.deleted == 1 && test.created == !status && test.published == status);
+        CHECK(!inst->connections->count);
+        if (!status) etcp_remove_new_conn_cbk(inst, cancel_created_connection, &test);
+        etcp_remove_conn_status_cbk(inst, observe_created_connection, &test);
+        uasync_drain_immediate(inst->ua); uasync_poll(inst->ua, 0);
+        printf("PASS connection creation cancelled from %s callback\n", status ? "NEW status" : "new connection");
+    }
+}
+
 struct link_close_case { struct ETCP_LINK *neighbor; unsigned events, nested; };
 static void close_neighbor(struct ETCP_CONN *conn, struct ETCP_LINK *link, int old_state, int old_status, void *arg) {
     (void)conn; (void)old_state; (void)old_status;
@@ -202,7 +231,7 @@ int main(void) {
         uasync_poll(inst.ua,0); CHECK(inst.connections->count == 0);
         printf("PASS lifecycle scenario %d\n",scenario+1);
     }
-    ncd_cases(&inst); ncd_late_up_case(&inst); recovery_cases(&inst); neighbor_close_case(&inst);
+    ncd_cases(&inst); ncd_late_up_case(&inst); recovery_cases(&inst); neighbor_close_case(&inst); constructor_close_cases(&inst);
     queue_free(inst.connections); uasync_poll(inst.ua,0);
     CHECK(inst.ua->timer_alloc_count == inst.ua->timer_free_count);
     uasync_destroy(inst.ua,0); CHECK(u_get_allocated_count() == baseline);