chatgui: add UtunNode C++ wrapper for embedded uTun node

- UtunNode runs uTun instance in a dedicated std::thread
- no TUN, no msg_transport — direct etcp_route_send/recv calls
- Thread-safe cross-thread communication via Qt signals
- C callback (etcp_recv_fn) stores UtunNode* via thread_local
- etcp_router_bind on service ID 0x11 for chat messages
- uasync_poll(100ms) loop runs until stop() called

tools/chatgui/transport/utun_node.cpp

@@ -0,0 +1,135 @@
+// utun_node.cpp — embedded uTun node running in a dedicated thread
+#include "utun_node.h"
+#include <cinttypes>
+
+// === C headers ===
+extern "C" {
+#include "utun_instance.h"
+#include "etcp_router.h"
+#include "etcp_api.h"
+#include "etcp.h"
+#include "config_parser.h"
+#include "config_updater.h"
+#include "control_server.h"
+#include "secure_channel.h"
+#include "../lib/u_async.h"
+#include "../lib/ll_queue.h"
+#include "../lib/memory_pool.h"
+#include "../lib/debug_config.h"
+#include "../lib/mem.h"
+}
+
+#define ETCP_RT_ID_CHAT  0x11
+
+static thread_local UtunNode* g_currentNode = nullptr;
+
+UtunNode::UtunNode(QObject* parent) : QObject(parent) {}
+
+UtunNode::~UtunNode() {
+    stop();
+}
+
+bool UtunNode::start(const QString& configPath) {
+    if (m_running) return false;
+    m_configPath = configPath;
+    m_stop = false;
+    m_running = true;
+    m_thread = std::thread(&UtunNode::runLoop, this);
+
+    for (int i = 0; i < 50 && m_running && !m_instance; ++i)
+        std::this_thread::sleep_for(std::chrono::milliseconds(10));
+
+    if (!m_instance) {
+        m_stop = true;
+        if (m_thread.joinable()) m_thread.join();
+        m_running = false;
+        return false;
+    }
+    emit started();
+    return true;
+}
+
+void UtunNode::stop() {
+    if (!m_running) return;
+    m_stop = true;
+    if (m_thread.joinable()) m_thread.join();
+    m_running = false;
+}
+
+void UtunNode::send(uint64_t dstNodeId, const QByteArray& data) {
+    if (!m_instance) return;
+    struct ll_entry* entry = queue_entry_new(data.size());
+    if (!entry) return;
+    memcpy(entry->data, data.constData(), data.size());
+    etcp_route_send(m_instance, dstNodeId, entry, 0);
+}
+
+QString UtunNode::nodeIdHex() const {
+    if (!m_instance) return {};
+    char buf[32];
+    snprintf(buf, sizeof(buf), "%016" PRIx64, m_instance->node_id);
+    return QString(buf);
+}
+
+QString UtunNode::pubKeyHex() const {
+    if (!m_instance || !m_instance->config) return {};
+    return QString::fromLatin1(m_instance->config->global.my_public_key_hex, 64);
+}
+
+void UtunNode::recvCallback(struct ETCP_CONN* conn, struct ll_entry* entry) {
+    if (!g_currentNode || !entry) return;
+    uint64_t src = conn ? conn->peer_node_id : 0;
+    QByteArray data((const char*)entry->data, (int)(entry->len ? entry->len : 0));
+    QMetaObject::invokeMethod(g_currentNode, [=] {
+        emit g_currentNode->messageReceived(src, data);
+    }, Qt::QueuedConnection);
+}
+
+void UtunNode::runLoop() {
+    g_currentNode = this;
+
+    debug_config_init();
+    debug_set_level(DEBUG_LEVEL_ERROR);
+    debug_enable_function_name(0);
+
+    utun_instance_set_tun_init_enabled(0);
+
+    struct UASYNC* ua = uasync_create();
+    if (!ua) {
+        QMetaObject::invokeMethod(this, [this] { emit error("uasync_create failed"); });
+        g_currentNode = nullptr;
+        return;
+    }
+
+    m_instance = utun_instance_create(ua, m_configPath.toUtf8().constData());
+    if (!m_instance) {
+        QMetaObject::invokeMethod(this, [this] { emit error("utun_instance_create failed"); });
+        uasync_destroy(ua, 0);
+        g_currentNode = nullptr;
+        return;
+    }
+
+    m_instance->test_user_ptr = this;
+
+    if (utun_instance_init(m_instance) != 0) {
+        QMetaObject::invokeMethod(this, [this] { emit error("utun_instance_init failed"); });
+        utun_instance_destroy(m_instance);
+        m_instance = nullptr;
+        uasync_destroy(ua, 0);
+        g_currentNode = nullptr;
+        return;
+    }
+
+    etcp_router_bind(m_instance, ETCP_RT_ID_CHAT, recvCallback);
+
+    while (!m_stop) {
+        uasync_poll(ua, 100);
+    }
+
+    etcp_router_bind(m_instance, ETCP_RT_ID_CHAT, nullptr);
+    utun_instance_destroy(m_instance);
+    m_instance = nullptr;
+    uasync_destroy(ua, 0);
+    g_currentNode = nullptr;
+    QMetaObject::invokeMethod(this, [this] { emit stopped(); });
+}