app - Android VpnService para capturar paquetes no capturará paquetes

wireshark android

Question

He estado buscando mi respuesta durante un par de horas y no puedo entenderlo. Por favor ayuda.

Lo que quiero hacer es usar VpnService en Android para obtener paquetes de red como la aplicación tPacketCapture

Empecé utilizando el código de muestra ToyVpn de google y lo modifiqué para no enviar los datos a un servidor. Sin embargo, no estoy seguro de si esto es correcto.

Mi método de configuración usa la dirección IP de wlan para binder.addAddress () antes de llamar a establecer (). Estoy usando un nexus 7 y utilicé "adb shell netcfg | grep wlan0" para obtener la dirección:

wlan0 UP 192.168.0.6/24 0x00001043 10: bf: 48: bf: 5f: 9d

Y agrégalo en mi método:

    private void configure() throws Exception {
    // If the old interface has exactly the same parameters, use it!
    if (mInterface != null) {
        Log.i(TAG, "Using the previous interface");
        return;
    }

    // Configure a builder while parsing the parameters.
    Builder builder = new Builder();
    builder.setMtu(1500);
    builder.addAddress("192.168.0.6", 24);

    try {
        mInterface.close();
    } catch (Exception e) {
        // ignore
    }

    mInterface = builder.establish();
}

Después de llamar a esto, llamo al método de ejecución que modifiqué para pasar una Cadena en lugar de una InetSocketAddress y esto no es importante porque no lo estoy usando en ninguna parte:

    private void run(String run) throws Exception {
    configure();

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

    // Allocate the buffer for a single packet.
    ByteBuffer packet = ByteBuffer.allocate(32767);

    // We use a timer to determine the status of the tunnel. It
    // works on both sides. A positive value means sending, and
    // any other means receiving. We start with receiving.
    int timer = 0;

    // We keep forwarding packets till something goes wrong.
    while (true) {
        // Assume that we did not make any progress in this iteration.
        boolean idle = true;

        // Read the outgoing packet from the input stream.
        int length = in.read(packet.array());
        if (length > 0) {

            Log.i(TAG,"************new packet");
            while (packet.hasRemaining()) {
                Log.i(TAG,""+packet.get());
                //System.out.print((char) packet.get());
            }

            // Write the outgoing packet to the tunnel.
            packet.limit(length);
            //  tunnel.write(packet);
            packet.clear();

            // There might be more outgoing packets.
            idle = false;

            // If we were receiving, switch to sending.
            if (timer < 1) {
                timer = 1;
            }
        }
    }
}

Cuando hago adb logcat, nada está sucediendo. ¿Estoy haciendo esto correctamente? Siento que me estoy perdiendo algo.

¡Gracias!

EDITAR:

De los registros veo las siguientes líneas:

I/ActivityManager(  460): START u0 {act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10000000 cmp=com.example.android.toyvpn/.ToyVpnClient} from pid 10247
I/ActivityManager(  460): Start proc com.example.android.toyvpn for activity com.example.android.toyvpn/.ToyVpnClient: pid=10287 uid=10122 gids={50122, 3003, 1028}
I/ActivityManager(  460): Displayed com.example.android.toyvpn/.ToyVpnClient: +1s144ms
I/Vpn     (  460): Switched from [Legacy VPN] to com.example.android.toyvpn
D/Vpn     (  460): setting state=IDLE, reason=prepare
I/ToyVpnService(10287): running vpnService
D/Vpn     (  460): setting state=CONNECTING, reason=establish
D/VpnJni  (  460): Address added on tun0: 192.168.0.6/24
I/Vpn     (  460): Established by com.example.android.toyvpn.ToyVpnService on tun0
W/ContextImpl(  460): Calling a method in the system process without a qualified user: android.app.ContextImpl.bindService:1406 com.android.server.connectivity.Vpn.establish:289 com.android.server.ConnectivityService.establishVpn:3263 android.net.IConnectivityManager$Stub.onTransact:504 android.os.Binder.execTransact:351 
D/Vpn     (  460): setting state=AUTHENTICATING, reason=establish

Parece que se está conectando.

Fuente completa:

public class ToyVpnService extends VpnService implements Handler.Callback, Runnable {
    private static final String TAG = "ToyVpnService";

    private Handler mHandler;
    private Thread mThread;

    private ParcelFileDescriptor mInterface;

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        // The handler is only used to show messages.
        if (mHandler == null) {
            mHandler = new Handler(this);
        }

        // Stop the previous session by interrupting the thread.
        if (mThread != null) {
            mThread.interrupt();
        }

        // Start a new session by creating a new thread.
        mThread = new Thread(this, "ToyVpnThread");
        mThread.start();
        return START_STICKY;
    }

    @Override
    public void onDestroy() {
        if (mThread != null) {
            mThread.interrupt();
        }
    }

    @Override
    public boolean handleMessage(Message message) {
        if (message != null) {
            Toast.makeText(this, message.what, Toast.LENGTH_SHORT).show();
        }
        return true;
    }

    @Override
    public synchronized void run() {
        Log.i(TAG,"running vpnService");
        try {
            runVpnConnection();
        } catch (Exception e) {
            e.printStackTrace();
            //Log.e(TAG, "Got " + e.toString());
        } finally {
            try {
                mInterface.close();
            } catch (Exception e) {
                // ignore
            }
            mInterface = null;

            mHandler.sendEmptyMessage(R.string.disconnected);
            Log.i(TAG, "Exiting");
        }
    }

    private boolean runVpnConnection() throws Exception {

        configure();

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

        // Allocate the buffer for a single packet.
        ByteBuffer packet = ByteBuffer.allocate(32767);

        // We keep forwarding packets till something goes wrong.
        while (true) {
            // Assume that we did not make any progress in this iteration.
            boolean idle = true;

            // Read the outgoing packet from the input stream.
            int length = in.read(packet.array());
            if (length > 0) {

                Log.i(TAG,"************new packet");
                System.exit(-1);
                while (packet.hasRemaining()) {
                    Log.i(TAG,""+packet.get());
                    //System.out.print((char) packet.get());
                }
                packet.limit(length);
                //  tunnel.write(packet);
                packet.clear();

                // There might be more outgoing packets.
                idle = false;
            }
            Thread.sleep(50);
        }
    }

    public String getLocalIpAddress()
    {
        try {
            for (Enumeration<NetworkInterface> en = NetworkInterface.getNetworkInterfaces(); en.hasMoreElements();) {
                NetworkInterface intf = en.nextElement();
                for (Enumeration<InetAddress> enumIpAddr = intf.getInetAddresses(); enumIpAddr.hasMoreElements();) {
                    InetAddress inetAddress = enumIpAddr.nextElement();
                    Log.i(TAG,"****** INET ADDRESS ******");
                    Log.i(TAG,"address: "+inetAddress.getHostAddress());
                    Log.i(TAG,"hostname: "+inetAddress.getHostName());
                    Log.i(TAG,"address.toString(): "+inetAddress.getHostAddress().toString());
                    if (!inetAddress.isLoopbackAddress()) {
                        //IPAddresses.setText(inetAddress.getHostAddress().toString());
                        Log.i(TAG,"IS NOT LOOPBACK ADDRESS: "+inetAddress.getHostAddress().toString());
                        return inetAddress.getHostAddress().toString();
                    } else{
                        Log.i(TAG,"It is a loopback address");
                    }
                }
            }
        } catch (SocketException ex) {
            String LOG_TAG = null;
            Log.e(LOG_TAG, ex.toString());
        }

        return null;
    }

    private void configure() throws Exception {
        // If the old interface has exactly the same parameters, use it!
        if (mInterface != null) {
            Log.i(TAG, "Using the previous interface");
            return;
        }

        // Configure a builder while parsing the parameters.
        Builder builder = new Builder();
        builder.setMtu(1500);
        builder.addAddress("192.168.0.6", 24);
        try {
            mInterface.close();
        } catch (Exception e) {
            // ignore
        }

        mInterface = builder.establish();
    }
}

Answer 1

Mi método de configuración usa la dirección IP de wlan para binder.addAddress () before> calling establish (). Estoy usando un nexus 7 y utilicé "adb shell netcfg | grep> wlan0" para obtener la dirección:

wlan0 UP 192.168.0.6/24 0x00001043 10: bf: 48: bf: 5f: 9d

He escrito un script simple en python para mostrarle netcfg gráficamente desde adb. Se actualiza cada segundo.

https://github.com/ilanben/graphical_netcfg

Disfruta :)

Answer 2

Ok, no fue nada fácil pero descubrí cómo capturar paquetes. Como no estoy muy familiarizado con la creación de redes (pero este nuevo trabajo me pide que lo haga) tuve dificultades para configurar todo correctamente. Básicamente después de establecer la ruta correcta en el VpnService.builder, recibí los paquetes correctamente.

Asi que:

builder.addAddress("192.168.0.6", 24); // was wrong, you need to put an internal IP (10.0.2.0 for example)

y

builder.addRoute("0.0.0.0", 0); // needs to be this.

no necesita configurar un DnsServer a través de builder.addDnsServer () para que funcione. Espero que esto ayude a cualquiera!