feat(client/macos): P1 方案B 骨架 — System Extension + NETunnelProviderManager 接线

把 PoC 的 sudo sing-box 外部二进制换成自包含、免 root 的 NEPacketTunnelProvider
(System Extension)+ 嵌入 libbox 的生产架构铺好骨架(不破坏现有 PoC 构建)。

- PacketTunnel/:扩展 target 源 — PacketTunnelProvider(LibboxSetup→NewService→start,
  openTun 建 NEPacketTunnelNetworkSettings)、Info.plist(NEProviderClasses)、
  entitlements(packet-tunnel-provider-systemextension + App Group)
- Runner/VpnChannel.swift:主 app 经 NETunnelProviderManager 启停 + 状态/速率回传,
  对齐 Dart 侧 VpnNativeBridge 的 pangolin/vpn channel 契约
- vpn_bridge_provider.dart:kUseNativeVpnMacOS 开关(默认 false,联调通过后置 true)
- docs/p1-macos-system-extension.md:文件清单 + Xcode/签名步骤 + 待办
  (Team BYL4KQHMTN;Network Extensions 已确认自助开通、无需 Apple 审批)

非破坏:新源文件未入 build target、注册行/app-group entitlements 均注释、gate 默认 false。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

client/lib/bridge/vpn_bridge_provider.dart

@@ -13,11 +13,20 @@ import 'vpn_bridge_mock.dart';
 // Web 平台须先检查 kIsWeb（dart:io 在 Web 上不可用）。
 import 'dart:io' show Platform;
 
+/// P1 方案B 开关:macOS 是否走原生 System Extension(VpnNativeBridge)而非 PoC 的
+/// sudo 子进程(DesktopVpnBridge)。默认 false——待 PacketTunnel target/签名就绪、
+/// 原生侧联调通过后置 true。见 docs/p1-macos-system-extension.md。
+const bool kUseNativeVpnMacOS = false;
+
 /// 全局单例 VpnBridge。Ref 生命周期内不变。
 final vpnBridgeProvider = Provider<VpnBridge>((ref) {
-  if (!kIsWeb &&
-      (Platform.isMacOS || Platform.isLinux || Platform.isWindows)) {
-    return DesktopVpnBridge();
+  if (!kIsWeb) {
+    if (Platform.isMacOS && kUseNativeVpnMacOS) {
+      return VpnNativeBridge();
+    }
+    if (Platform.isMacOS || Platform.isLinux || Platform.isWindows) {
+      return DesktopVpnBridge();
+    }
   }
   return VpnBridgeMock();
 });

client/macos/PacketTunnel/Info.plist

@@ -0,0 +1,38 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>CFBundleDevelopmentRegion</key>
+	<string>$(DEVELOPMENT_LANGUAGE)</string>
+	<key>CFBundleDisplayName</key>
+	<string>Pangolin Tunnel</string>
+	<key>CFBundleExecutable</key>
+	<string>$(EXECUTABLE_NAME)</string>
+	<key>CFBundleIdentifier</key>
+	<string>$(PRODUCT_BUNDLE_IDENTIFIER)</string>
+	<key>CFBundleInfoDictionaryVersion</key>
+	<string>6.0</string>
+	<key>CFBundleName</key>
+	<string>$(PRODUCT_NAME)</string>
+	<key>CFBundlePackageType</key>
+	<string>$(PRODUCT_BUNDLE_PACKAGE_TYPE)</string>
+	<key>CFBundleShortVersionString</key>
+	<string>$(MARKETING_VERSION)</string>
+	<key>CFBundleVersion</key>
+	<string>$(CURRENT_PROJECT_VERSION)</string>
+	<!-- System Extension 主体声明:NEPacketTunnelProvider。
+	     NetworkExtension 框架据此把扩展类与 packet-tunnel 类型绑定。 -->
+	<key>NetworkExtension</key>
+	<dict>
+		<key>NEMachServiceName</key>
+		<string>$(TeamIdentifierPrefix)group.com.pangolin.pangolin</string>
+		<key>NEProviderClasses</key>
+		<dict>
+			<key>com.apple.networkextension.packet-tunnel</key>
+			<string>$(PRODUCT_MODULE_NAME).PacketTunnelProvider</string>
+		</dict>
+	</dict>
+	<key>CFBundlePackageType</key>
+	<string>XPC!</string>
+</dict>
+</plist>

client/macos/PacketTunnel/PacketTunnel.entitlements

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<!-- Packet Tunnel Provider(System Extension 形态:站外 Developer ID 分发用 -systemextension 后缀)。
+	     在 Identifiers → com.pangolin.pangolin.tunnel 勾 Network Extensions 即获得此权限。 -->
+	<key>com.apple.developer.networking.networkextension</key>
+	<array>
+		<string>packet-tunnel-provider-systemextension</string>
+	</array>
+	<!-- 与主 app 共享配置/状态(同一 App Group) -->
+	<key>com.apple.security.application-groups</key>
+	<array>
+		<string>group.com.pangolin.pangolin</string>
+	</array>
+</dict>
+</plist>

client/macos/PacketTunnel/PacketTunnelProvider.swift

@@ -0,0 +1,124 @@
+// PacketTunnelProvider.swift — Pangolin macOS System Extension(方案B / P1 骨架)
+//
+// 角色:运行在独立 sysex 进程的 NEPacketTunnelProvider。把嵌入的 sing-box(libbox)
+// 拉起来建 TUN,免 root、自包含(替代 PoC 的 `sudo sing-box run` 外部二进制)。
+//
+// 数据流(详见 docs/p1-macos-system-extension.md):
+//   主 app(Flutter)经 NETunnelProviderManager.startVPNTunnel(options:) 下发 sing-box
+//   JSON → 本扩展 startTunnel 收到 → LibboxSetup(App Group 路径)→ LibboxNewService(json,
+//   platformInterface)→ start;libbox 回调 platformInterface.openTun 时,我们据其网络配置
+//   建 NEPacketTunnelNetworkSettings + setTunnelNetworkSettings,把 packetFlow 的 fd 交回。
+//   运行态速率/状态经 libbox CommandServer(loopback)被主 app 的 CommandClient 订阅。
+//
+// ⚠️ 编译前置:
+//   1. 工程已加入 Libbox.xcframework(scripts/build-libbox.sh apple macos 产出)。
+//   2. 本 target 链接 NetworkExtension + Libbox。
+//   3. PangolinPlatformInterface 对 LibboxPlatformInterfaceProtocol 的**完整**实现需
+//      对照官方 sing-box-for-apple 的 ExtensionPlatformInterface 补齐(本文件只搭关键路径)。
+
+import NetworkExtension
+import os
+// import Libbox   // ← gomobile bind 产物;加入 xcframework 后解开
+
+private let log = Logger(subsystem: "com.pangolin.pangolin.tunnel", category: "provider")
+
+class PacketTunnelProvider: NEPacketTunnelProvider {
+    // libbox 服务句柄(类型来自 Libbox 模块,加入 xcframework 后改为 LibboxBoxService)。
+    private var boxService: AnyObject?
+    private var platformInterface: PangolinPlatformInterface?
+
+    // App Group 共享容器:放 sing-box 工作目录(缓存/日志)。主 app 与扩展同路径。
+    private static let appGroup = "group.com.pangolin.pangolin"
+
+    override func startTunnel(options: [String: NSObject]?) async throws {
+        log.info("startTunnel")
+
+        // 1) sing-box JSON:优先取 startVPNTunnel 下发的 options["configContent"],
+        //    否则回退读 App Group 共享文件(主 app 写入)。
+        let configContent: String
+        if let inline = options?["configContent"] as? String, !inline.isEmpty {
+            configContent = inline
+        } else {
+            configContent = (try? Self.readSharedConfig()) ?? ""
+        }
+        guard !configContent.isEmpty else {
+            throw NSError(domain: "pangolin.tunnel", code: 1,
+                          userInfo: [NSLocalizedDescriptionKey: "empty sing-box config"])
+        }
+
+        // 2) libbox 基础路径(全部落在 App Group 容器内,sysess 沙盒可写)。
+        guard let base = FileManager.default
+            .containerURL(forSecurityApplicationGroupIdentifier: Self.appGroup) else {
+            throw NSError(domain: "pangolin.tunnel", code: 2,
+                          userInfo: [NSLocalizedDescriptionKey: "no app group container"])
+        }
+        let work = base.appendingPathComponent("work", isDirectory: true)
+        try? FileManager.default.createDirectory(at: work, withIntermediateDirectories: true)
+
+        /* ── 加入 Libbox.xcframework 后解开以下真实接线 ──────────────────────
+        var setupError: NSError?
+        let setup = LibboxSetupOptions()
+        setup.basePath = base.path
+        setup.workingPath = work.path
+        setup.tempPath = NSTemporaryDirectory()
+        LibboxSetup(setup, &setupError)
+        if let setupError { throw setupError }
+
+        let platform = PangolinPlatformInterface(provider: self)
+        self.platformInterface = platform
+
+        var newError: NSError?
+        guard let service = LibboxNewService(configContent, platform, &newError) else {
+            throw newError ?? NSError(domain: "pangolin.tunnel", code: 3)
+        }
+        self.boxService = service
+        try service.start()
+        ──────────────────────────────────────────────────────────────────── */
+
+        // 骨架占位:xcframework 接入前,startTunnel 直接抛错,避免静默假成功。
+        throw NSError(domain: "pangolin.tunnel", code: 99, userInfo: [
+            NSLocalizedDescriptionKey:
+                "Libbox 尚未接入(见 docs/p1-macos-system-extension.md 步骤 3)",
+        ])
+    }
+
+    override func stopTunnel(with reason: NEProviderStopReason) async {
+        log.info("stopTunnel reason=\(reason.rawValue)")
+        /* if let service = boxService as? LibboxBoxService { try? service.close() } */
+        boxService = nil
+        platformInterface = nil
+    }
+
+    // 主 app 经 sendProviderMessage 下发的控制(切节点等);也可改走 libbox CommandServer。
+    override func handleAppMessage(_ messageData: Data) async -> Data? {
+        nil
+    }
+
+    private static func readSharedConfig() throws -> String {
+        guard let base = FileManager.default
+            .containerURL(forSecurityApplicationGroupIdentifier: appGroup) else {
+            throw NSError(domain: "pangolin.tunnel", code: 2)
+        }
+        let url = base.appendingPathComponent("config.json")
+        return try String(contentsOf: url, encoding: .utf8)
+    }
+}
+
+/// libbox ↔ NetworkExtension 桥(LibboxPlatformInterfaceProtocol)。
+///
+/// 关键职责是 openTun:libbox 把所需网络参数(地址/路由/DNS/MTU)交给我们,我们据此建
+/// NEPacketTunnelNetworkSettings、setTunnelNetworkSettings,并返回 packetFlow 对应的 tun fd。
+///
+/// ⚠️ 本类只是骨架声明。完整协议(openTun / writeLog / useProcFS / findConnectionOwner /
+/// defaultInterfaceMonitor / getInterfaces / underNetworkExtension / systemCertificates 等)
+/// 需对照官方 ExtensionPlatformInterface 补齐后才能编译通过。见安装文档步骤 3。
+final class PangolinPlatformInterface: NSObject {
+    private weak var provider: NEPacketTunnelProvider?
+
+    init(provider: NEPacketTunnelProvider) {
+        self.provider = provider
+    }
+
+    // 示意:openTun 的核心是把 libbox 的网络配置翻译成 NEPacketTunnelNetworkSettings。
+    // 真实签名以 Libbox 头文件为准(LibboxTunOptions / 返回 tun fd)。
+}

client/macos/Runner/DebugProfile.entitlements

@@ -15,5 +15,11 @@
 	<array>
 		<string>$(AppIdentifierPrefix)com.pangolin.pangolin</string>
 	</array>
+	<!-- P1 方案B:接 System Extension 时在此加(注册 App Group 后,见 p1-macos-system-extension.md §3):
+	<key>com.apple.security.application-groups</key>
+	<array>
+		<string>group.com.pangolin.pangolin</string>
+	</array>
+	-->
 </dict>
 </plist>

client/macos/Runner/MainFlutterWindow.swift

@@ -14,6 +14,11 @@ class MainFlutterWindow: NSWindow {
 
     RegisterGeneratedPlugins(registry: flutterViewController)
 
+    // P1 方案B:VPN 原生控制通道。把 VpnChannel.swift 加入 Runner target(Compile Sources)
+    // 后,解开下一行注册(见 docs/p1-macos-system-extension.md §3)。在此之前保持注释,
+    // 以免引用未编译符号破坏 Runner 构建。
+    // VpnChannel.register(with: flutterViewController.registrar(forPlugin: "VpnChannel"))
+
     super.awakeFromNib()
   }
 }

client/macos/Runner/Release.entitlements

@@ -11,5 +11,11 @@
 	<array>
 		<string>$(AppIdentifierPrefix)com.pangolin.pangolin</string>
 	</array>
+	<!-- P1 方案B:接 System Extension 时在此加(注册 App Group 后,见 p1-macos-system-extension.md §3):
+	<key>com.apple.security.application-groups</key>
+	<array>
+		<string>group.com.pangolin.pangolin</string>
+	</array>
+	-->
 </dict>
 </plist>

client/macos/Runner/VpnChannel.swift

@@ -0,0 +1,164 @@
+// VpnChannel.swift — 主 app 侧 VPN 控制(方案B / P1 骨架)
+//
+// 把 Flutter 的 pangolin/vpn(MethodChannel)+ pangolin/vpn/status、pangolin/vpn/stats
+// (EventChannel)接到 NETunnelProviderManager:安装/启停 PacketTunnel System Extension、
+// 回传状态与速率。契约对齐 client/lib/bridge/vpn_bridge.dart 的 VpnNativeBridge。
+//
+// 注册:在 MainFlutterWindow.awakeFromNib 里 `VpnChannel.register(with: flutterViewController)`。
+//
+// ⚠️ 站外分发首启需先**激活 System Extension**(OSSystemExtensionRequest,见
+//    activateSystemExtensionIfNeeded + 安装文档步骤 4),用户会在「系统设置→隐私与安全性」
+//    点允许;激活成功后 NETunnelProviderManager 才能加载该 provider。
+
+import FlutterMacOS
+import NetworkExtension
+import SystemExtensions
+import os
+
+private let log = Logger(subsystem: "com.pangolin.pangolin", category: "vpn")
+
+final class VpnChannel: NSObject {
+    private static let tunnelBundleId = "com.pangolin.pangolin.tunnel"
+
+    private var statusSink: FlutterEventSink?
+    private var statsSink: FlutterEventSink?
+    private var statusObserver: NSObjectProtocol?
+    private var statsTimer: Timer?
+    private var manager: NETunnelProviderManager?
+
+    static func register(with registrar: FlutterPluginRegistrar) {
+        let instance = VpnChannel()
+        let method = FlutterMethodChannel(name: "pangolin/vpn",
+                                          binaryMessenger: registrar.messenger)
+        method.setMethodCallHandler(instance.handle)
+
+        FlutterEventChannel(name: "pangolin/vpn/status", binaryMessenger: registrar.messenger)
+            .setStreamHandler(StatusStreamHandler(owner: instance))
+        FlutterEventChannel(name: "pangolin/vpn/stats", binaryMessenger: registrar.messenger)
+            .setStreamHandler(StatsStreamHandler(owner: instance))
+
+        instance.observeStatus()
+    }
+
+    // ── MethodChannel ───────────────────────────────────────────────
+    private func handle(_ call: FlutterMethodCall, _ result: @escaping FlutterResult) {
+        switch call.method {
+        case "start":
+            guard let configJson = call.arguments as? String else {
+                result(FlutterError(code: "bad_args", message: "expected config json", details: nil))
+                return
+            }
+            Task { await self.start(configJson, result) }
+        case "stop":
+            Task { await self.stop(result) }
+        case "getStatus":
+            result(Self.statusString(manager?.connection.status ?? .invalid))
+        case "selectOutbound":
+            // TODO: 经 sendProviderMessage / libbox CommandClient 切 outbound。
+            result(nil)
+        case "getActiveOutbound":
+            result("auto")
+        case "setKillSwitch":
+            // includeAllNetworks / on-demand 实现 kill switch(后续)。
+            result(nil)
+        default:
+            result(FlutterMethodNotImplemented)
+        }
+    }
+
+    private func start(_ configJson: String, _ result: @escaping FlutterResult) async {
+        do {
+            try await activateSystemExtensionIfNeeded()
+            let mgr = try await loadOrCreateManager()
+            self.manager = mgr
+            try mgr.connection.startVPNTunnel(options: [
+                "configContent": configJson as NSString,
+            ])
+            result(nil)
+        } catch {
+            log.error("start failed: \(error.localizedDescription)")
+            result(FlutterError(code: "start_failed", message: error.localizedDescription, details: nil))
+        }
+    }
+
+    private func stop(_ result: @escaping FlutterResult) async {
+        manager?.connection.stopVPNTunnel()
+        result(nil)
+    }
+
+    // ── NETunnelProviderManager 装配 ────────────────────────────────
+    private func loadOrCreateManager() async throws -> NETunnelProviderManager {
+        let all = try await NETunnelProviderManager.loadAllFromPreferences()
+        let mgr = all.first ?? NETunnelProviderManager()
+        let proto = (mgr.protocolConfiguration as? NETunnelProviderProtocol) ?? NETunnelProviderProtocol()
+        proto.providerBundleIdentifier = Self.tunnelBundleId
+        proto.serverAddress = "Pangolin"          // 仅展示用
+        mgr.protocolConfiguration = proto
+        mgr.localizedDescription = "Pangolin"
+        mgr.isEnabled = true
+        try await mgr.saveToPreferences()
+        try await mgr.loadFromPreferences()       // 保存后重载,拿到有效 connection
+        return mgr
+    }
+
+    // 站外 sysex 首次需用户授权激活。
+    private func activateSystemExtensionIfNeeded() async throws {
+        // TODO(P1): OSSystemExtensionRequest.activationRequest(
+        //   forExtensionWithIdentifier: tunnelBundleId, queue: .main) + delegate 等待结果。
+        // 已激活则直接返回。详见安装文档步骤 4。
+    }
+
+    // ── 状态 / 速率回传 ─────────────────────────────────────────────
+    private func observeStatus() {
+        statusObserver = NotificationCenter.default.addObserver(
+            forName: .NEVPNStatusDidChange, object: nil, queue: .main
+        ) { [weak self] note in
+            guard let conn = note.object as? NEVPNConnection else { return }
+            self?.statusSink?(Self.statusString(conn.status))
+        }
+    }
+
+    fileprivate func onStatusListen(_ sink: @escaping FlutterEventSink) {
+        statusSink = sink
+        sink(Self.statusString(manager?.connection.status ?? .invalid))
+    }
+    fileprivate func onStatusCancel() { statusSink = nil }
+
+    fileprivate func onStatsListen(_ sink: @escaping FlutterEventSink) {
+        statsSink = sink
+        // TODO(P1): 接 libbox CommandClient 订阅实时速率;骨架先每秒推占位 0。
+        statsTimer = Timer.scheduledTimer(withTimeInterval: 1, repeats: true) { [weak self] _ in
+            self?.statsSink?(["up": 0, "down": 0, "uplinkTotal": 0, "downlinkTotal": 0])
+        }
+    }
+    fileprivate func onStatsCancel() { statsTimer?.invalidate(); statsTimer = nil; statsSink = nil }
+
+    private static func statusString(_ s: NEVPNStatus) -> String {
+        switch s {
+        case .connected: return "on"
+        case .connecting, .reasserting: return "connecting"
+        case .disconnecting: return "disconnecting"
+        case .disconnected, .invalid: return "off"
+        @unknown default: return "error"
+        }
+    }
+}
+
+// EventChannel 流处理器。
+private final class StatusStreamHandler: NSObject, FlutterStreamHandler {
+    weak var owner: VpnChannel?
+    init(owner: VpnChannel) { self.owner = owner }
+    func onListen(withArguments _: Any?, eventSink events: @escaping FlutterEventSink) -> FlutterError? {
+        owner?.onStatusListen(events); return nil
+    }
+    func onCancel(withArguments _: Any?) -> FlutterError? { owner?.onStatusCancel(); return nil }
+}
+
+private final class StatsStreamHandler: NSObject, FlutterStreamHandler {
+    weak var owner: VpnChannel?
+    init(owner: VpnChannel) { self.owner = owner }
+    func onListen(withArguments _: Any?, eventSink events: @escaping FlutterEventSink) -> FlutterError? {
+        owner?.onStatsListen(events); return nil
+    }
+    func onCancel(withArguments _: Any?) -> FlutterError? { owner?.onStatsCancel(); return nil }
+}