[fix] update MiniRTC SRTP replay handling and bandwidth accounting

apps/desktop/src/config_center/config_center.cpp

@@ -103,7 +103,12 @@ int ConfigCenter::Load() {
     ini_.SetLongValue(section_, "turn_mode", static_cast<long>(turn_mode_));
     persist_config_migration = true;
   }
-  enable_srtp_ = ini_.GetBoolValue(section_, "enable_srtp", enable_srtp_);
+  // Migrate the former user switch. Keep true in the file for older builds,
+  // while the current application always requests encrypted native media.
+  if (!ini_.GetBoolValue(section_, "enable_srtp", false)) {
+    ini_.SetBoolValue(section_, "enable_srtp", true);
+    persist_config_migration = true;
+  }
   enable_self_hosted_ =
       ini_.GetBoolValue(section_, "enable_self_hosted", enable_self_hosted_);
 
@@ -165,7 +170,7 @@ int ConfigCenter::Save() {
   ini_.SetLongValue(section_, "turn_mode", static_cast<long>(turn_mode_));
   ini_.SetBoolValue(section_, "enable_turn",
                     turn_mode_ != TURN_MODE::DISABLED);
-  ini_.SetBoolValue(section_, "enable_srtp", enable_srtp_);
+  ini_.SetBoolValue(section_, "enable_srtp", true);
   ini_.SetBoolValue(section_, "enable_self_hosted", enable_self_hosted_);
 
   // only save when self hosted
@@ -301,16 +306,6 @@ int ConfigCenter::SetTurn(bool enable_turn) {
   return SetTurnMode(turn_mode_);
 }
 
-int ConfigCenter::SetSrtp(bool enable_srtp) {
-  enable_srtp_ = enable_srtp;
-  ini_.SetBoolValue(section_, "enable_srtp", enable_srtp_);
-  SI_Error rc = ini_.SaveFile(config_path_.c_str());
-  if (rc < 0) {
-    return -1;
-  }
-  return 0;
-}
-
 int ConfigCenter::SetServerHost(const std::string& signal_server_host) {
   signal_server_host_ = signal_server_host;
   ini_.SetValue(section_, "signal_server_host", signal_server_host_.c_str());
@@ -472,7 +467,7 @@ bool ConfigCenter::IsEnableTurn() const {
   return turn_mode_ != TURN_MODE::DISABLED;
 }
 
-bool ConfigCenter::IsEnableSrtp() const { return enable_srtp_; }
+bool ConfigCenter::IsEnableSrtp() const { return true; }
 
 std::string ConfigCenter::GetSignalServerHost() const {
   return signal_server_host_;

apps/desktop/src/config_center/config_center.h

@@ -47,7 +47,6 @@ class ConfigCenter {
   int SetHardwareVideoCodec(bool hardware_video_codec);
   int SetTurnMode(TURN_MODE turn_mode);
   int SetTurn(bool enable_turn);
-  int SetSrtp(bool enable_srtp);
   int SetServerHost(const std::string& signal_server_host);
   int SetServerPort(int signal_server_port);
   int SetSelfHosted(bool enable_self_hosted);
@@ -99,7 +98,6 @@ class ConfigCenter {
   VIDEO_ENCODE_FORMAT video_encode_format_ = VIDEO_ENCODE_FORMAT::H264;
   bool hardware_video_codec_ = false;
   TURN_MODE turn_mode_ = TURN_MODE::AUTO_UDP_TCP;
-  bool enable_srtp_ = false;
   std::string signal_server_host_ = "";
   std::string signal_server_host_default_ = "api.crossdesk.cn";
   int signal_server_port_ = 0;

apps/desktop/src/gui/application/gui_application.cpp

@@ -1230,7 +1230,6 @@ void GuiApplication::ResetSettingsUi() {
   ui_->main->set_hardware_codec_enabled(hardware_codec_available &&
                                        enable_hardware_video_codec_);
   ui_->main->set_turn_enabled(enable_turn_);
-  ui_->main->set_srtp_enabled(enable_srtp_);
   ui_->main->set_self_hosted_enabled(enable_self_hosted_);
   ui_->main->set_autostart_enabled(enable_autostart_);
   ui_->main->set_daemon_enabled(enable_daemon_);
@@ -2419,7 +2418,6 @@ void GuiApplication::SyncStreamWindow() {
     return;
   }
   (*ui_->stream)->set_window_maximized((*ui_->stream)->window().is_maximized());
-  (*ui_->stream)->set_srtp_enabled(enable_srtp_);
 #if defined(__APPLE__)
   if (ui_->stream_live_resize_configuration_attempts > 0) {
     if (ConfigureStreamWindowLiveResize(
@@ -2987,7 +2985,6 @@ void GuiApplication::SaveSettingsFromUi() {
   enable_hardware_video_codec_ = ConfigCenter::IsHardwareVideoCodecAvailable() &&
                                   main->get_hardware_codec_enabled();
   enable_turn_ = main->get_turn_enabled();
-  enable_srtp_ = main->get_srtp_enabled();
   enable_self_hosted_ = main->get_self_hosted_enabled();
   enable_autostart_ = main->get_autostart_enabled();
   enable_daemon_ = main->get_daemon_enabled();
@@ -3010,7 +3007,6 @@ void GuiApplication::SaveSettingsFromUi() {
           video_encode_format_button_value_));
   config_center_->SetHardwareVideoCodec(enable_hardware_video_codec_);
   config_center_->SetTurn(enable_turn_);
-  config_center_->SetSrtp(enable_srtp_);
   config_center_->SetSelfHosted(enable_self_hosted_);
   config_center_->SetAutostart(enable_autostart_);
   config_center_->SetDaemon(enable_daemon_);
@@ -3056,7 +3052,6 @@ void GuiApplication::SaveSettingsFromUi() {
   video_encode_format_button_value_last_ = video_encode_format_button_value_;
   enable_hardware_video_codec_last_ = enable_hardware_video_codec_;
   enable_turn_last_ = enable_turn_;
-  enable_srtp_last_ = enable_srtp_;
   enable_self_hosted_last_ = enable_self_hosted_;
   enable_autostart_last_ = enable_autostart_;
   enable_daemon_last_ = enable_daemon_;

apps/desktop/src/gui/assets/layouts/layout.h

@@ -53,8 +53,6 @@
 #define ENABLE_HARDWARE_VIDEO_CODEC_CHECKBOX_PADDING_EN 218 * dpi_scale_
 #define ENABLE_TURN_CHECKBOX_PADDING_CN 171 * dpi_scale_
 #define ENABLE_TURN_CHECKBOX_PADDING_EN 218 * dpi_scale_
-#define ENABLE_SRTP_CHECKBOX_PADDING_CN 171 * dpi_scale_
-#define ENABLE_SRTP_CHECKBOX_PADDING_EN 218 * dpi_scale_
 #define ENABLE_SELF_HOSTED_SERVER_CHECKBOX_PADDING_CN 171 * dpi_scale_
 #define ENABLE_SELF_HOSTED_SERVER_CHECKBOX_PADDING_EN 218 * dpi_scale_
 #define ENABLE_AUTOSTART_PADDING_CN 171 * dpi_scale_

apps/desktop/src/gui/assets/layouts/layout_relative.h

@@ -57,8 +57,6 @@
 #define ENABLE_HARDWARE_VIDEO_CODEC_CHECKBOX_PADDING_EN 218
 #define ENABLE_TURN_CHECKBOX_PADDING_CN 171
 #define ENABLE_TURN_CHECKBOX_PADDING_EN 218
-#define ENABLE_SRTP_CHECKBOX_PADDING_CN 171
-#define ENABLE_SRTP_CHECKBOX_PADDING_EN 218
 #define ENABLE_SELF_HOSTED_SERVER_CHECKBOX_PADDING_CN 171
 #define ENABLE_SELF_HOSTED_SERVER_CHECKBOX_PADDING_EN 218
 #define ENABLE_AUTOSTART_PADDING_CN 171

apps/desktop/src/gui/assets/localization/localization_data.h

@@ -149,7 +149,6 @@ struct TranslationRow {
     "Enable Hardware Video Codec:", u8"Использовать аппаратный кодек:")        \
   X(enable_turn, u8"启用中继服务:",                                            \
     "Enable TURN Service:", u8"Включить TURN-сервис:")                         \
-  X(enable_srtp, u8"启用SRTP:", "Enable SRTP:", u8"Включить SRTP:")            \
   X(self_hosted_server_config, u8"自托管配置", "Self-Hosted Config",           \
     u8"Конфигурация self-hosted")                                              \
   X(self_hosted_server_settings, u8"自托管设置", "Self-Hosted Settings",       \

apps/desktop/src/gui/features/settings/settings_manager.cpp

@@ -308,7 +308,6 @@ int SettingsManager::Load() {
   owner_.enable_hardware_video_codec_ =
       owner_.config_center_->IsHardwareVideoCodec();
   owner_.enable_turn_ = owner_.config_center_->IsEnableTurn();
-  owner_.enable_srtp_ = owner_.config_center_->IsEnableSrtp();
   owner_.enable_self_hosted_ = owner_.config_center_->IsSelfHosted();
   owner_.enable_autostart_ = owner_.config_center_->IsEnableAutostart();
   owner_.enable_daemon_ = owner_.config_center_->IsEnableDaemon();
@@ -335,7 +334,6 @@ int SettingsManager::Load() {
   owner_.enable_hardware_video_codec_last_ =
       owner_.enable_hardware_video_codec_;
   owner_.enable_turn_last_ = owner_.enable_turn_;
-  owner_.enable_srtp_last_ = owner_.enable_srtp_;
   owner_.enable_self_hosted_last_ = owner_.enable_self_hosted_;
   owner_.enable_autostart_last_ = owner_.enable_autostart_;
 

apps/desktop/src/gui/runtime/runtime_state.h

@@ -136,7 +136,6 @@ struct UserSettingsState {
   int video_encode_format_button_value_ = 0;
   bool enable_hardware_video_codec_ = true;
   bool enable_turn_ = true;
-  bool enable_srtp_ = false;
   char signal_server_ip_[256] = "api.crossdesk.cn";
   char signal_server_port_[6] = "9099";
   bool enable_self_hosted_ = false;
@@ -147,7 +146,6 @@ struct UserSettingsState {
   int video_encode_format_button_value_last_ = 0;
   bool enable_hardware_video_codec_last_ = false;
   bool enable_turn_last_ = true;
-  bool enable_srtp_last_ = false;
   bool enable_self_hosted_last_ = false;
   bool enable_autostart_ = false;
   bool enable_autostart_last_ = false;

apps/desktop/src/gui/ui/main_window.slint

@@ -48,7 +48,6 @@ export global UiStrings {
     in-out property <string> codec: "Video codec";
     in-out property <string> hardware-codec: "Hardware video codec";
     in-out property <string> turn-relay: "TURN relay";
-    in-out property <string> srtp: "SRTP encryption";
     in-out property <string> self-hosted: "Self-hosted server";
     in-out property <string> autostart: "Start with system";
     in-out property <string> daemon: "Run in background";
@@ -247,7 +246,6 @@ export component MainWindow inherits Window {
     in-out property <int> codec-index: 0;
     in-out property <bool> hardware-codec-enabled: true;
     in-out property <bool> turn-enabled: true;
-    in-out property <bool> srtp-enabled: false;
     in-out property <bool> self-hosted-enabled: false;
     in-out property <bool> autostart-enabled: false;
     in-out property <bool> daemon-enabled: false;
@@ -1488,11 +1486,6 @@ export component MainWindow inherits Window {
                         Text { x: 8px; y: 3px; width: root.compact-language ? 145px : 212px; height: 24px; text: UiStrings.turn-relay; font-size: ImGuiFontStyle.body; overflow: elide; vertical-alignment: center; }
                         ImGuiCheckBox { x: root.compact-language ? 157px : 224px; y: 3px; checked <=> root.turn-enabled; enabled: !root.settings-session-active; }
                     }
-                    Rectangle {
-                        height: 30px;
-                        Text { x: 8px; y: 3px; width: root.compact-language ? 145px : 212px; height: 24px; text: UiStrings.srtp; font-size: ImGuiFontStyle.body; overflow: elide; vertical-alignment: center; }
-                        ImGuiCheckBox { x: root.compact-language ? 157px : 224px; y: 3px; checked <=> root.srtp-enabled; enabled: !root.settings-session-active; }
-                    }
                     Rectangle {
                         height: 30px;
                         Text { x: 8px; y: 3px; width: root.compact-language ? 145px : 212px; height: 24px; text: UiStrings.privacy-on-connect; color: root.privacy-setting-available ? #202124 : #8b8f95; font-size: ImGuiFontStyle.body; overflow: elide; vertical-alignment: center; }

apps/desktop/src/gui/ui/stream_window.slint

@@ -160,7 +160,6 @@ export component StreamWindow inherits Window {
     in property <bool> remote-cursor-active: false;
     in property <int> remote-cursor-shape: 0;
     in property <bool> audio-enabled: true;
-    in property <bool> srtp-enabled: false;
     in property <bool> fullscreen-enabled: false;
     in property <bool> stats-visible: false;
     in property <[NetworkStatsRow]> stats-rows;
@@ -506,20 +505,8 @@ export component StreamWindow inherits Window {
                         width: parent.width - 27px;
                         height: parent.height;
                         background: transparent;
-                        if root.srtp-enabled: Text {
-                            x: 0px;
-                            width: 12px;
-                            height: parent.height;
-                            text: FontAwesomeIcons.shield-halved;
-                            color: #30343b;
-                            font-family: "Font Awesome 6 Free";
-                            font-weight: 900;
-                            font-size: ImGuiFontStyle.base;
-                            horizontal-alignment: center;
-                            vertical-alignment: center;
-                        }
                         Text {
-                            x: root.srtp-enabled ? 16px : 0px;
+                            x: 0px;
                             width: parent.width - self.x;
                             height: parent.height;
                             text: tab.title;

apps/desktop/src/gui/ui/ui_localization.h

@@ -69,7 +69,6 @@ inline int ApplyMainWindowStrings(
   strings.set_hardware_codec(
       Text(localization::enable_hardware_video_codec[language]));
   strings.set_turn_relay(Text(localization::enable_turn[language]));
-  strings.set_srtp(Text(localization::enable_srtp[language]));
   strings.set_self_hosted(
       Text(localization::self_hosted_server_config[language]));
   strings.set_autostart(Text(localization::enable_autostart[language]));

apps/desktop/src/gui/views/windows/main_settings_window.cpp

@@ -268,25 +268,6 @@ int GuiApplication::SettingWindow() {
 
       ImGui::Separator();
 
-      {
-        settings_items_offset += settings_items_padding;
-        ImGui::SetCursorPosY(settings_items_offset);
-        ImGui::AlignTextToFramePadding();
-        ImGui::Text(
-            "%s",
-            localization::enable_srtp[localization_language_index_].c_str());
-        ImGui::SameLine();
-        if (ConfigCenter::LANGUAGE::CHINESE == localization_language_) {
-          ImGui::SetCursorPosX(title_bar_button_width_ * 4.275f);
-        } else {
-          ImGui::SetCursorPosX(title_bar_button_width_ * 5.955f);
-        }
-
-        ImGui::Checkbox("##enable_srtp", &enable_srtp_);
-      }
-
-      ImGui::Separator();
-
       {
         settings_items_offset += settings_items_padding;
         ImGui::SetCursorPosY(settings_items_offset + 1);
@@ -569,14 +550,6 @@ int GuiApplication::SettingWindow() {
         }
         enable_turn_last_ = enable_turn_;
 
-        // SRTP
-        if (enable_srtp_) {
-          config_center_->SetSrtp(true);
-        } else {
-          config_center_->SetSrtp(false);
-        }
-        enable_srtp_last_ = enable_srtp_;
-
         if (enable_self_hosted_) {
           config_center_->SetSelfHosted(true);
         } else {

apps/desktop/src/gui/views/windows/stream_window.cpp

@@ -136,10 +136,7 @@ int GuiApplication::StreamWindow() {
           continue;
         }
 
-        std::string tab_label =
-            enable_srtp_
-                ? std::string(ICON_FA_SHIELD_HALVED) + " " + props->remote_id_
-                : props->remote_id_;
+        const std::string& tab_label = props->remote_id_;
         if (ImGui::BeginTabItem(tab_label.c_str(), &props->tab_opened_)) {
           props->tab_selected_ = true;
           ImGui::SetWindowFontScale(0.6f);
@@ -308,4 +305,4 @@ int GuiApplication::StreamWindow() {
 
   return 0;
 }
-} // namespace crossdesk
+} // namespace crossdesk

apps/ios/CrossDeskMobile/Bridge/CrossDeskRTCBridge.h

@@ -99,8 +99,7 @@ typedef NS_ENUM(NSInteger, CrossDeskVideoAdaptationPolicy) {
 @property(nonatomic, weak, nullable) id<CrossDeskRTCBridgeDelegate> delegate;
 
 - (void)configureWithSignalHost:(NSString *)host
-                     signalPort:(NSInteger)signalPort
-                     enableSRTP:(BOOL)enableSRTP;
+                     signalPort:(NSInteger)signalPort;
 - (void)setHardwareAccelerationEnabled:(BOOL)enabled;
 - (void)setVideoAdaptationPolicy:(CrossDeskVideoAdaptationPolicy)policy;
 - (void)requestPresenceForRemoteIDs:(NSArray<NSString *> *)remoteIDs

apps/ios/CrossDeskMobile/Bridge/CrossDeskRTCBridge.mm

@@ -75,7 +75,6 @@ struct RTCState {
   CallbackContext controller_context;
   std::string signal_host;
   int signal_port = 0;
-  bool enable_srtp = false;
   bool hardware_acceleration = true;
   VideoDegradationPreference video_adaptation_policy =
       VideoDegradationPreference::MaintainResolution;
@@ -86,6 +85,7 @@ struct RTCState {
   std::string identity_base;
   std::string controller_login;
   std::string pending_remote_id;
+  uint64_t pending_controller_generation = 0;
   std::string pending_password;
   std::string transmission_id;
   std::string log_path;
@@ -336,7 +336,7 @@ Params MakeParams(const RTCState &state, const std::string &user_id,
   params.native_video_output = true;
   params.av1_encoding = false;
   params.turn_mode = TurnMode::TurnAutoUdpTcp;
-  params.enable_srtp = state.enable_srtp;
+  params.enable_srtp = true;
   params.video_content_type = VideoContentType::ScreenContent;
   params.video_quality = VideoQuality::QualityHigh;
   params.video_frame_rate = 60;
@@ -432,8 +432,7 @@ Params MakeParams(const RTCState &state, const std::string &user_id,
 }
 
 - (void)configureWithSignalHost:(NSString *)host
-                     signalPort:(NSInteger)signalPort
-                     enableSRTP:(BOOL)enableSRTP {
+                     signalPort:(NSInteger)signalPort {
   NSString *trimmed = [host stringByTrimmingCharactersInSet:
                                 NSCharacterSet.whitespaceAndNewlineCharacterSet];
   const char *host_c_string = trimmed.UTF8String;
@@ -455,7 +454,6 @@ Params MakeParams(const RTCState &state, const std::string &user_id,
   dispatch_async(_rtcQueue, ^{
     const bool unchanged = self->_state->signal_host == host_value &&
                            self->_state->signal_port == signalPort &&
-                           self->_state->enable_srtp == enableSRTP &&
                            self->_state->identity_peer != nullptr;
     if (unchanged) return;
 
@@ -463,7 +461,6 @@ Params MakeParams(const RTCState &state, const std::string &user_id,
     [self destroyIdentityPeer];
     self->_state->signal_host = host_value;
     self->_state->signal_port = static_cast<int>(signalPort);
-    self->_state->enable_srtp = enableSRTP;
     self->_state->log_path = log_path;
     self->_state->identity_ready = false;
     self->_state->identity_recovery_attempted = false;
@@ -583,8 +580,14 @@ Params MakeParams(const RTCState &state, const std::string &user_id,
       password_c_string ? password_c_string : "";
   if (identifier.empty()) return;
 
+  // Invalidate queued callbacks immediately, before asynchronous teardown. A
+  // canceled attempt for the same remote must not close a newly started one.
+  const uint64_t generation = _controllerGenerationCounter.fetch_add(1) + 1;
+  _activeControllerGeneration.store(0);
   dispatch_async(_rtcQueue, ^{
+    if (generation != self->_controllerGenerationCounter.load()) return;
     self->_state->pending_remote_id = identifier;
+    self->_state->pending_controller_generation = generation;
     self->_state->pending_password = password_value;
     [self destroyControllerPeer];
     if (self->_state->identity_ready &&
@@ -595,6 +598,8 @@ Params MakeParams(const RTCState &state, const std::string &user_id,
 }
 
 - (void)disconnect {
+  _controllerGenerationCounter.fetch_add(1);
+  _activeControllerGeneration.store(0);
   dispatch_async(_rtcQueue, ^{
     self->_state->pending_remote_id.clear();
     self->_state->pending_password.clear();
@@ -868,7 +873,8 @@ Params MakeParams(const RTCState &state, const std::string &user_id,
       _state->identity_base.empty()) {
     return;
   }
-  const uint64_t generation = _controllerGenerationCounter.fetch_add(1) + 1;
+  const uint64_t generation = _state->pending_controller_generation;
+  if (generation == 0 || generation != _controllerGenerationCounter.load()) return;
   _state->controller_context.generation = generation;
   _activeControllerGeneration.store(generation);
   _state->controller_login = "C-" + _state->identity_base;
@@ -1112,6 +1118,8 @@ Params MakeParams(const RTCState &state, const std::string &user_id,
                       remoteID:(const std::string &)remoteID
                     generation:(uint64_t)generation {
   if (![self isControllerGenerationCurrent:generation]) return;
+  if (state != CrossDeskConnectionStateFailed &&
+      ![self isControllerGenerationActive:generation]) return;
   const std::string remote_copy = remoteID;
   if (state == CrossDeskConnectionStateConnected) {
     dispatch_async(_rtcQueue, ^{
@@ -1149,7 +1157,7 @@ Params MakeParams(const RTCState &state, const std::string &user_id,
   }
   DispatchMain(^{
     if (![self isControllerGenerationCurrent:generation]) return;
-    if (state == CrossDeskConnectionStateConnected &&
+    if (state != CrossDeskConnectionStateFailed &&
         ![self isControllerGenerationActive:generation]) {
       return;
     }
@@ -1164,6 +1172,7 @@ Params MakeParams(const RTCState &state, const std::string &user_id,
 
 - (BOOL)isControllerGenerationActive:(uint64_t)generation {
   return generation != 0 &&
+         _controllerGenerationCounter.load() == generation &&
          _activeControllerGeneration.load() == generation;
 }
 

apps/ios/CrossDeskMobile/ContentView.swift

@@ -17,6 +17,14 @@ struct ContentView: View {
         }
         .animation(.easeInOut(duration: 0.2), value: session.sessionVisible)
         .preferredColorScheme(session.sessionVisible ? .dark : .light)
+        .alert("连接提示", isPresented: Binding(
+            get: { session.connectionFailureMessage != nil },
+            set: { if !$0 { session.dismissConnectionFailure() } }
+        )) {
+            Button("确定", role: .cancel) { session.dismissConnectionFailure() }
+        } message: {
+            Text(session.connectionFailureMessage ?? "")
+        }
         .onAppear {
             if !session.sessionVisible {
                 AppOrientation.update(to: .portrait)
@@ -710,17 +718,14 @@ private struct ServerSettingsView: View {
                         .font(.caption)
                         .foregroundStyle(.tertiary)
                 }
-                Section("服务器") {
+                Section {
                     TextField("信令服务器", text: $session.signalHost)
                         .textInputAutocapitalization(.never)
                         .autocorrectionDisabled()
                     TextField("信令端口", text: $session.signalPort)
                         .keyboardType(.numberPad)
-                }
-                Section {
-                    Toggle("启用 SRTP", isOn: $session.enableSRTP)
                 } header: {
-                    Text("传输")
+                    Text("服务器")
                 } footer: {
                     Text(session.localIdentity.isEmpty
                          ? "正在获取本机 ID…"

apps/ios/CrossDeskMobile/RemoteSessionModel.swift

@@ -358,7 +358,6 @@ private final class RemoteAudioPlayer {
 final class RemoteSessionModel: NSObject, ObservableObject, CrossDeskRTCBridgeDelegate {
     @Published var signalHost = "api.crossdesk.cn"
     @Published var signalPort = "9099"
-    @Published var enableSRTP = false
     @Published var mouseControlMode = MouseControlMode.saved {
         didSet { mouseControlMode.save() }
     }
@@ -398,6 +397,7 @@ final class RemoteSessionModel: NSObject, ObservableObject, CrossDeskRTCBridgeDe
     @Published private(set) var recentConnections = RecentConnectionStore.load()
     @Published private(set) var recentConnectionPresence: [String: Bool] = [:]
     @Published private(set) var deviceOfflineAlertVisible = false
+    @Published private(set) var connectionFailureMessage: String?
 
     let bridge = CrossDeskRTCBridge()
     private let audioPlayer = RemoteAudioPlayer()
@@ -424,7 +424,6 @@ final class RemoteSessionModel: NSObject, ObservableObject, CrossDeskRTCBridgeDe
     private struct BridgeConfiguration: Equatable {
         let host: String
         let signalPort: Int
-        let enableSRTP: Bool
     }
     private var bridgeConfiguration: BridgeConfiguration?
 
@@ -457,8 +456,7 @@ final class RemoteSessionModel: NSObject, ObservableObject, CrossDeskRTCBridgeDe
             signalStatus = "服务器配置无效"
             return false
         }
-        let configuration = BridgeConfiguration(host: host, signalPort: signal,
-                                                enableSRTP: enableSRTP)
+        let configuration = BridgeConfiguration(host: host, signalPort: signal)
         if bridgeConfiguration != configuration {
             bridgeConfiguration = configuration
             signalConnected = false
@@ -472,8 +470,7 @@ final class RemoteSessionModel: NSObject, ObservableObject, CrossDeskRTCBridgeDe
         bridge.setHardwareAccelerationEnabled(videoCodecMode == .hardware)
         bridge.setVideoAdaptationPolicy(videoAdaptationPolicy.bridgeValue)
         bridge.configure(withSignalHost: host,
-                         signalPort: signal,
-                         enableSRTP: enableSRTP)
+                         signalPort: signal)
         return true
     }
 
@@ -484,6 +481,7 @@ final class RemoteSessionModel: NSObject, ObservableObject, CrossDeskRTCBridgeDe
     }
 
     func connect() {
+        connectionFailureMessage = nil
         let identifier = remoteID.trimmingCharacters(in: .whitespacesAndNewlines)
         guard !identifier.isEmpty else {
             connectionStatus = "请输入远程设备 ID"
@@ -576,7 +574,25 @@ final class RemoteSessionModel: NSObject, ObservableObject, CrossDeskRTCBridgeDe
         deviceOfflineAlertVisible = false
     }
 
+    func dismissConnectionFailure() {
+        guard connectionFailureMessage != nil else { return }
+        connectionFailureMessage = nil
+    }
+
+    private func finishConnection(withError message: String) {
+        // Cleanup may emit Closed. Preserve the terminal reason independently
+        // of the progress view and invalidate those callbacks in the bridge.
+        resetConnection()
+        connectionStatus = message
+        connectionFailureMessage = message
+    }
+
     func disconnect() {
+        resetConnection()
+    }
+
+    private func resetConnection() {
+        connectionFailureMessage = nil
         cancelVideoRecovery()
         let wasCheckingPresence = pendingPresenceRemoteID != nil
         cancelPresenceProbe()
@@ -882,6 +898,10 @@ final class RemoteSessionModel: NSObject, ObservableObject, CrossDeskRTCBridgeDe
     func rtcBridge(_ bridge: CrossDeskRTCBridge,
                    didChange state: CrossDeskConnectionState,
                    remoteID: String) {
+        guard isConnecting || isConnected || sessionVisible,
+              remoteID.isEmpty || remoteID == activeRemoteID else {
+            return
+        }
         isConnected = state.rawValue == 1
         if !isConnected {
             cancelVideoRecovery()
@@ -897,35 +917,25 @@ final class RemoteSessionModel: NSObject, ObservableObject, CrossDeskRTCBridgeDe
             bridge.setAudioEnabled(audioEnabled)
             AppOrientation.update(to: .allButUpsideDown)
         case 2: connectionStatus = "正在收集 ICE 候选"
-        case 3: connectionStatus = "网络连接已中断"
+        case 3: finishConnection(withError: "网络连接已中断，请重新连接。")
         case 4:
-            connectionStatus = "P2P/TURN 建链失败"
-            sessionVisible = false
-            AppOrientation.update(to: .portrait)
+            finishConnection(withError: "P2P/TURN 建链失败，请检查网络后重试。")
         case 5:
-            connectionStatus = "未连接"
-            sessionVisible = false
-            AppOrientation.update(to: .portrait)
+            finishConnection(withError: "远程连接已结束。")
         case 6:
-            connectionStatus = "访问密码错误"
-            sessionVisible = false
-            AppOrientation.update(to: .portrait)
+            finishConnection(withError: "访问密码错误，请重新输入。")
         case 7:
-            connectionStatus = "远程设备 ID 不存在"
             if !remoteID.isEmpty {
                 recentConnectionPresence[remoteID] = false
                 presenceUpdatedAt.removeValue(forKey: remoteID)
             }
-            sessionVisible = false
-            AppOrientation.update(to: .portrait)
+            finishConnection(withError: "远程设备 ID 不存在，请检查设备 ID。")
         case 8:
-            connectionStatus = "远程设备当前不可用"
             if !remoteID.isEmpty {
                 recentConnectionPresence[remoteID] = false
                 presenceUpdatedAt.removeValue(forKey: remoteID)
             }
-            sessionVisible = false
-            AppOrientation.update(to: .portrait)
+            finishConnection(withError: "远程设备当前不可用，请稍后重试。")
         default: connectionStatus = "未知连接状态"
         }
     }