Android VpnService捕获数据包不会发送数据包

Question

我希望新的android（4.0）VpnService接口实现简单的数据包捕获和分析。我已成功从filedescriptor捕获数据包（IP数据包），但由于我没有服务器，我想直接将数据包发送到其原始目的地。我尝试从数据包中获取IP和端口，用于创建保护隧道和发送数据包。但是，当我使用Fiddler进行检测时，我什么都没得到。

    private Thread mThread;
    private ParcelFileDescriptor mInterface;
    private static String TAG = "VPN_SERVICE";

    Builder builder = new Builder();

    @Override
    public int onStartCommand(Intent intent, final int flags, int startId) {

        mThread = new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    mInterface = builder.setSession("MyVPNService")
                            .addAddress("192.168.0.1", 24)
                           // .addDnsServer("8.8.8.8")
                            .addRoute("0.0.0.0", 0)
                            .establish();

                    FileInputStream in = new FileInputStream(mInterface.getFileDescriptor());


                    FileOutputStream out1 = openFileOutput("216427.txt", Context.MODE_APPEND);


                    ByteBuffer packet = ByteBuffer.allocate(512);
                    int length;
                    while (true){
                        while ((length = in.read(packet.array())) > 0){
                            packet.limit(length);

                            out1.write(packet.array());
                            ResolvePacket resolvePacket = new ResolvePacket();
                            resolvePacket.debugPacket(packet);

                            String desIP = resolvePacket.DESTINATION_IP;
                            String desPORT = resolvePacket.DESTINATION_PORT;

                            Log.d("IP + PORT:", "*******" + desIP + "******" + desPORT + "******");

                            DatagramChannel tmp_tunnel = DatagramChannel.open();
                            tmp_tunnel.connect(new InetSocketAddress(desIP, Integer.parseInt(desPORT)));
                            protect(tmp_tunnel.socket());
                            tmp_tunnel.write(packet);
                            tmp_tunnel.close();


                            packet.clear();
                        }


                    }


                }catch (Exception e){
                    e.printStackTrace();
                }finally {
                    try {
                        if(mInterface != null){
                            mInterface.close();
                            mInterface = null;
                        }
                    }catch (Exception e){
                        e.printStackTrace();
                    }
                }
            }
        }, "MyVpnRunnable");
        mThread.start();
        return START_STICKY;
    }