TestTunnelWithArbitraryTCPTraffic.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package gobblin.tunnel;

import static org.testng.Assert.assertEquals;
import static org.testng.Assert.assertFalse;
import static org.testng.Assert.assertNotEquals;
import static org.testng.Assert.assertTrue;

import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.nio.ByteBuffer;
import java.nio.channels.SocketChannel;
import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.commons.codec.binary.Hex;
import org.apache.commons.lang.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.testng.annotations.AfterClass;
import org.testng.annotations.BeforeClass;
import org.testng.annotations.Test;

/**
 * Tests for Tunnel with arbitrary TCP traffic.
 *
 * @author kkandekar@linkedin.com
 */
@Test(singleThreaded = true, groups = { "gobblin.tunnel", "disabledOnTravis" })
public class TestTunnelWithArbitraryTCPTraffic {
  private static final Logger LOG = LoggerFactory.getLogger(TestTunnelWithArbitraryTCPTraffic.class);

  MockServer doubleEchoServer;
  MockServer delayedDoubleEchoServer;
  MockServer talkFirstEchoServer;

  @BeforeClass
  void setUp() throws IOException {
    doubleEchoServer = startDoubleEchoServer();
    LOG.info("Double Echo Server on " + doubleEchoServer.getServerSocketPort());
    delayedDoubleEchoServer = startDoubleEchoServer(1000);
    LOG.info("Delayed DoubleEchoServer on " + delayedDoubleEchoServer.getServerSocketPort());
    talkFirstEchoServer = startTalkFirstEchoServer();
    LOG.info("TalkFirstEchoServer on " + talkFirstEchoServer.getServerSocketPort());
  }

  @AfterClass
  void cleanUp() {
    doubleEchoServer.stopServer();
    delayedDoubleEchoServer.stopServer();
    talkFirstEchoServer.stopServer();
    MockServer.sleepQuietly(100);
    int nAlive = 0;
    for (EasyThread t : EasyThread.ALL_THREADS) {
      if (t.isAlive()) {
        LOG.warn(t + " IS ALIVE!");
        nAlive++;
      }
    }
    LOG.warn("Threads left alive " + nAlive);
  }

  private MockServer startConnectProxyServer(final boolean largeResponse,
                                             final boolean mixServerAndProxyResponse,
                                             final int nBytesToCloseSocketAfter) throws IOException {
    return new ConnectProxyServer(mixServerAndProxyResponse, largeResponse, nBytesToCloseSocketAfter).start();
  }

  private MockServer startConnectProxyServer(final boolean largeResponse,
                                             final boolean mixServerAndProxyResponse) throws IOException {
    return startConnectProxyServer(largeResponse, mixServerAndProxyResponse, -1);
  }

  private MockServer startConnectProxyServer() throws IOException {
    return startConnectProxyServer(false, false);
  }

  private MockServer startDoubleEchoServer() throws IOException {
    return startDoubleEchoServer(0);
  }

  private MockServer startDoubleEchoServer(final long delay) throws IOException {
    return new DoubleEchoServer(delay).start();
  }

  private static String readFromSocket(SocketChannel client) throws IOException {
    ByteBuffer readBuf = ByteBuffer.allocate(256);
    LOG.info("Reading from client");
    client.read(readBuf);
    readBuf.flip();
    return StandardCharsets.US_ASCII.decode(readBuf).toString();
  }

  private static void writeToSocket(SocketChannel client, byte [] bytes) throws IOException {
    client.write(ByteBuffer.wrap(bytes));
    client.socket().getOutputStream().flush();
  }

  // Baseline test to ensure clients work without tunnel
  @Test(timeOut = 15000)
  public void testDirectConnectionToEchoServer() throws IOException {
    SocketChannel client = SocketChannel.open();
    try {
      client.connect(new InetSocketAddress("localhost", doubleEchoServer.getServerSocketPort()));
      writeToSocket(client, "Knock\n".getBytes());
      String response = readFromSocket(client);
      client.close();
      assertEquals(response, "Knock Knock\n");
    } finally {
      client.close();
    }
  }

  @Test(timeOut = 15000)
  public void testTunnelToEchoServer() throws IOException {
    MockServer proxyServer = startConnectProxyServer();
    Tunnel tunnel = Tunnel.build("localhost", doubleEchoServer.getServerSocketPort(), "localhost",
        proxyServer.getServerSocketPort());

    try {
      int tunnelPort = tunnel.getPort();
      SocketChannel client = SocketChannel.open();

      client.connect(new InetSocketAddress("localhost", tunnelPort));
      client.write(ByteBuffer.wrap("Knock\n".getBytes()));
      String response = readFromSocket(client);
      client.close();

      assertEquals(response, "Knock Knock\n");
      assertEquals(proxyServer.getNumConnects(), 1);
    } finally {
      proxyServer.stopServer();
      tunnel.close();
      assertFalse(tunnel.isTunnelThreadAlive());
    }
  }


  @Test(timeOut = 15000)
  public void testTunnelToDelayedEchoServer() throws IOException {
    MockServer proxyServer = startConnectProxyServer();
    Tunnel tunnel = Tunnel.build("localhost", delayedDoubleEchoServer.getServerSocketPort(), "localhost",
        proxyServer.getServerSocketPort());

    try {
      int tunnelPort = tunnel.getPort();
      SocketChannel client = SocketChannel.open();

      client.connect(new InetSocketAddress("localhost", tunnelPort));
      client.write(ByteBuffer.wrap("Knock\n".getBytes()));
      String response = readFromSocket(client);
      client.close();

      assertEquals(response, "Knock Knock\n");
      assertEquals(proxyServer.getNumConnects(), 1);
    } finally {
      proxyServer.stopServer();
      tunnel.close();
      assertFalse(tunnel.isTunnelThreadAlive());
    }
  }

  @Test(timeOut = 15000)
  public void testTunnelToEchoServerMultiRequest() throws IOException {
    MockServer proxyServer = startConnectProxyServer();
    Tunnel tunnel = Tunnel.build("localhost", doubleEchoServer.getServerSocketPort(),
        "localhost", proxyServer.getServerSocketPort());

    try {
      int tunnelPort = tunnel.getPort();
      SocketChannel client = SocketChannel.open();

      client.connect(new InetSocketAddress("localhost", tunnelPort));
      client.write(ByteBuffer.wrap("Knock\n".getBytes()));
      String response1 = readFromSocket(client);

      client.write(ByteBuffer.wrap("Hello\n".getBytes()));
      String response2 = readFromSocket(client);

      client.close();

      assertEquals(response1, "Knock Knock\n");
      assertEquals(response2, "Hello Hello\n");
      assertEquals(proxyServer.getNumConnects(), 1);
    } finally {
      proxyServer.stopServer();
      tunnel.close();
      assertFalse(tunnel.isTunnelThreadAlive());
    }
  }

  private MockServer startTalkFirstEchoServer() throws IOException {
    return new TalkFirstDoubleEchoServer().start();
  }

  private void runClientToTalkFirstServer(int tunnelPort) throws IOException {
    SocketChannel client = SocketChannel.open();

    client.connect(new InetSocketAddress("localhost", tunnelPort));
    String response0 = readFromSocket(client);
    LOG.info(response0);

    client.write(ByteBuffer.wrap("Knock\n".getBytes()));
    String response1 = readFromSocket(client);
    LOG.info(response1);


    client.write(ByteBuffer.wrap("Hello\n".getBytes()));
    String response2 = readFromSocket(client);
    LOG.info(response2);

    client.close();

    assertEquals(response0, "Hello\n");
    assertEquals(response1, "Knock Knock\n");
    assertEquals(response2, "Hello Hello\n");
  }

  @Test(timeOut = 15000)
  public void testTunnelToEchoServerThatRespondsFirst() throws IOException {
    MockServer proxyServer = startConnectProxyServer();
    Tunnel tunnel = Tunnel.build("localhost", talkFirstEchoServer.getServerSocketPort(),
        "localhost", proxyServer.getServerSocketPort());

    try {
      int tunnelPort = tunnel.getPort();
      runClientToTalkFirstServer(tunnelPort);
      assertEquals(proxyServer.getNumConnects(), 1);
    } finally {
      proxyServer.stopServer();
      tunnel.close();
      assertFalse(tunnel.isTunnelThreadAlive());
    }
  }

  @Test(timeOut = 15000)
  public void testTunnelToEchoServerThatRespondsFirstWithMixedProxyAndServerResponseInBuffer() throws IOException {
    MockServer proxyServer = startConnectProxyServer(false, true);
    Tunnel tunnel = Tunnel.build("localhost", talkFirstEchoServer.getServerSocketPort(),
        "localhost", proxyServer.getServerSocketPort());

    try {
      int tunnelPort = tunnel.getPort();
      runClientToTalkFirstServer(tunnelPort);
      assertEquals(proxyServer.getNumConnects(), 1);
    } finally {
      proxyServer.stopServer();
      tunnel.close();
      assertFalse(tunnel.isTunnelThreadAlive());
    }
  }

  @Test(timeOut = 15000)
  public void testTunnelToEchoServerThatRespondsFirstAcrossMultipleDrainReads() throws IOException {
    MockServer proxyServer = startConnectProxyServer(true, true);
    Tunnel tunnel = Tunnel.build("localhost", talkFirstEchoServer.getServerSocketPort(),
        "localhost", proxyServer.getServerSocketPort());

    try {
      int tunnelPort = tunnel.getPort();
      runClientToTalkFirstServer(tunnelPort);
      assertEquals(proxyServer.getNumConnects(), 1);
    } finally {
      proxyServer.stopServer();
      tunnel.close();
      assertFalse(tunnel.isTunnelThreadAlive());
    }
  }

  @Test(timeOut = 15000)
  public void testTunnelToEchoServerThatRespondsFirstAcrossMultipleDrainReadsWithMultipleClients()
      throws IOException, InterruptedException {
    MockServer proxyServer = startConnectProxyServer(true, true);
    Tunnel tunnel = Tunnel.build("localhost", talkFirstEchoServer.getServerSocketPort(),
        "localhost", proxyServer.getServerSocketPort());

    try {
      final int tunnelPort = tunnel.getPort();
      List<EasyThread> threads = new ArrayList<EasyThread>();
      for (int i = 0; i < 5; i++) {
        threads.add(new EasyThread() {
          @Override
          void runQuietly() throws Exception {
            try {
              runClientToTalkFirstServer(tunnelPort);
            } catch (IOException e) {
              e.printStackTrace();
            }
          }
        }.startThread());
      }
      for (Thread t : threads) {
        t.join();
      }
      assertEquals(proxyServer.getNumConnects(), 5);
    } finally {
      proxyServer.stopServer();
      tunnel.close();
      assertFalse(tunnel.isTunnelThreadAlive());
    }
  }

  private void runSimultaneousDataExchange(boolean useTunnel, int nclients)
      throws IOException, InterruptedException, NoSuchAlgorithmException {
    long t0 = System.currentTimeMillis();
    final int nMsgs = 50;
    final Map<String, MessageDigest> digestMsgsRecvdAtServer = new HashMap<String, MessageDigest>();
    final Map<String, MessageDigest> digestMsgsSentByClients = new HashMap<String, MessageDigest>();
    final Map<String, MessageDigest> digestMsgsRecvdAtClients = new HashMap<String, MessageDigest>();
    for (int c = 0; c < nclients ; c++) {
      digestMsgsRecvdAtServer.put(Integer.toString(c), MessageDigest.getInstance("MD5"));
      digestMsgsSentByClients.put(Integer.toString(c), MessageDigest.getInstance("MD5"));
      digestMsgsRecvdAtClients.put(Integer.toString(c), MessageDigest.getInstance("MD5"));
    }
    final MessageDigest digestMsgsSentByServer = MessageDigest.getInstance("MD5");
    for (int i = 0; i < nMsgs; i++) {
      digestMsgsSentByServer.update(TalkPastServer.generateMsgFromServer(i).getBytes());
    }
    String hashOfMsgsSentByServer = Hex.encodeHexString(digestMsgsSentByServer.digest());

    MockServer talkPastServer = startTalkPastServer(nMsgs, digestMsgsRecvdAtServer);

    int targetPort = talkPastServer.getServerSocketPort();
    Tunnel tunnel = null;
    MockServer proxyServer = null;
    if (useTunnel) {
      proxyServer = startConnectProxyServer();
      tunnel = Tunnel.build("localhost", talkPastServer.getServerSocketPort(),
          "localhost", proxyServer.getServerSocketPort());
      targetPort = tunnel.getPort();
    }

    try {
      List<EasyThread> clientThreads = new ArrayList<EasyThread>();
      final int portToUse = targetPort;
      for (int c = 0; c < nclients; c++) {
        final int clientId = c;
        clientThreads.add(new EasyThread() {
          @Override
          void runQuietly() throws Exception {
            long t = System.currentTimeMillis();
            LOG.info("\t" + clientId + ": Client starting");
            final MessageDigest digestMsgsRecvdAtClient = digestMsgsRecvdAtClients.get(Integer.toString(clientId));
            //final SocketChannel client = SocketChannel.open(); // tunnel test hangs for some reason with SocketChannel
            final Socket client = new Socket();
            client.connect(new InetSocketAddress("localhost", portToUse));
            EasyThread serverReaderThread = new EasyThread() {
              @Override
              public void runQuietly() {
                try {
                  BufferedReader clientIn = new BufferedReader(new InputStreamReader(client.getInputStream()));
                  String line = clientIn.readLine();
                  while (line != null && !line.equals("Goodbye")) {
                    //LOG.info("\t" + clientId + ": Server said [" + line.substring(0, 32) + "... ]");
                    digestMsgsRecvdAtClient.update(line.getBytes());
                    digestMsgsRecvdAtClient.update("\n".getBytes());
                    line = clientIn.readLine();
                  }
                } catch (IOException e) {
                  e.printStackTrace();
                }
                LOG.info("\t" + clientId + ": Client done reading");
              }
            }.startThread();

            MessageDigest hashMsgsFromClient = digestMsgsSentByClients.get(Integer.toString(clientId));
            BufferedOutputStream clientOut = new BufferedOutputStream(client.getOutputStream());
            for (int i = 0; i < nMsgs; i++) {
              String msg = clientId + ":" + i + " " + StringUtils.repeat("Blahhh Blahhh ", 10000) +"\n";
              //LOG.info(clientId + " sending " + msg.length() + " bytes");
              byte [] bytes = msg.getBytes();
              hashMsgsFromClient.update(bytes);
              clientOut.write(bytes);
              MockServer.sleepQuietly(2);
            }
            clientOut.write(("Goodbye\n".getBytes()));
            clientOut.flush();
            LOG.info("\t" + clientId + ": Client done writing in " + (System.currentTimeMillis() - t) + " ms");
            serverReaderThread.join();
            LOG.info("\t" + clientId + ": Client done in " + (System.currentTimeMillis() - t) + " ms");
            client.close();
          }
        }.startThread());
      }
      for (Thread clientThread : clientThreads) {
        clientThread.join();
      }
      LOG.info("All data transfer done in " + (System.currentTimeMillis() - t0) + " ms");
    } finally {
      talkPastServer.stopServer();
      if (tunnel != null) {
        proxyServer.stopServer();
        tunnel.close();
        assertFalse(tunnel.isTunnelThreadAlive());
        assertEquals(proxyServer.getNumConnects(), nclients);
      }

      Map<String, String> hashOfMsgsRecvdAtServer = new HashMap<String, String>();
      Map<String, String> hashOfMsgsSentByClients = new HashMap<String, String>();
      Map<String, String> hashOfMsgsRecvdAtClients = new HashMap<String, String>();
      for (int c = 0; c < nclients; c++) {
        String client = Integer.toString(c);
        hashOfMsgsRecvdAtServer.put(client, Hex.encodeHexString(digestMsgsRecvdAtServer.get(client).digest()));
        hashOfMsgsSentByClients.put(client, Hex.encodeHexString(digestMsgsSentByClients.get(client).digest()));
        hashOfMsgsRecvdAtClients.put(client, Hex.encodeHexString(digestMsgsRecvdAtClients.get(client).digest()));
      }

      LOG.info("\tComparing client sent to server received");
      assertEquals(hashOfMsgsSentByClients, hashOfMsgsRecvdAtServer);

      LOG.info("\tComparing server sent to client received");
      for (String hashOfMsgsRecvdAtClient : hashOfMsgsRecvdAtClients.values()) {
        assertEquals(hashOfMsgsSentByServer, hashOfMsgsRecvdAtClient);
      }
      LOG.info("\tDone");
    }
  }

  private MockServer startTalkPastServer(final int nMsgs, final Map<String, MessageDigest> digestMsgsRecvdAtServer) throws IOException {
    return new TalkPastServer(nMsgs, digestMsgsRecvdAtServer).start();
  }

  // Baseline tests to ensure simultaneous data transfer protocol is fine (disabled for now)
  @Test(enabled = false, timeOut = 15000)
  public void testSimultaneousDataExchangeWithDirectConnection()
      throws IOException, InterruptedException, NoSuchAlgorithmException {
    runSimultaneousDataExchange(false, 1);
  }

  @Test(enabled = false, timeOut = 15000)
  public void testSimultaneousDataExchangeWithDirectConnectionAndMultipleClients()
      throws IOException, InterruptedException, NoSuchAlgorithmException {
    runSimultaneousDataExchange(false, 3);
  }

  /*
    I wrote this test because I saw this symptom once randomly while testing with Gobblin. Test passes, but occasionally
    we see the following warning in the logs:

    15/10/29 21:11:17 WARN tunnel.Tunnel: exception handling event on java.nio.channels.SocketChannel[connected local=/127.0.0.1:34669 remote=/127.0.0.1:38578]
    java.nio.channels.CancelledKeyException
      at sun.nio.ch.SelectionKeyImpl.ensureValid(SelectionKeyImpl.java:73)
      at sun.nio.ch.SelectionKeyImpl.readyOps(SelectionKeyImpl.java:87)
      at java.nio.channels.SelectionKey.isWritable(SelectionKey.java:312)
      at gobblin.tunnel.Tunnel$ReadWriteHandler.write(Tunnel.java:423)
      at gobblin.tunnel.Tunnel$ReadWriteHandler.call(Tunnel.java:403)
      at gobblin.tunnel.Tunnel$ReadWriteHandler.call(Tunnel.java:365)
      at gobblin.tunnel.Tunnel$Dispatcher.dispatch(Tunnel.java:142)
      at gobblin.tunnel.Tunnel$Dispatcher.run(Tunnel.java:127)
      at java.lang.Thread.run(Thread.java:745)
   */
  @Test(timeOut = 20000)
  public void testSimultaneousDataExchangeWithTunnel()
      throws IOException, InterruptedException, NoSuchAlgorithmException {
    runSimultaneousDataExchange(true, 1);
  }

  @Test(timeOut = 20000)
  public void testSimultaneousDataExchangeWithTunnelAndMultipleClients()
      throws IOException, InterruptedException, NoSuchAlgorithmException {
    runSimultaneousDataExchange(true, 3);
  }

  @Test(expectedExceptions = IOException.class)
  public void testTunnelWhereProxyConnectionToServerFailsWithWriteFirstClient() throws IOException, InterruptedException {
    MockServer proxyServer = startConnectProxyServer();
    final int nonExistentPort = 54321; // hope this doesn't exist!
    Tunnel tunnel = Tunnel.build("localhost", nonExistentPort, "localhost", proxyServer.getServerSocketPort());
    try {
      int tunnelPort = tunnel.getPort();
      SocketChannel client = SocketChannel.open();

      client.configureBlocking(true);
      client.connect(new InetSocketAddress("localhost", tunnelPort));
      // Might have to write multiple times before connection error propagates back from proxy through tunnel to client
      for (int i = 0; i < 5; i++) {
        client.write(ByteBuffer.wrap("Knock\n".getBytes()));
        Thread.sleep(100);
      }
      String response1 = readFromSocket(client);
      LOG.info(response1);

      client.close();

    } finally {
      proxyServer.stopServer();
      tunnel.close();
      assertFalse(tunnel.isTunnelThreadAlive());
      assertEquals(proxyServer.getNumConnects(), 1);
    }
  }

  @Test(timeOut = 15000)
  public void testTunnelThreadDeadAfterClose() throws IOException, InterruptedException {
    MockServer proxyServer = startConnectProxyServer();
    Tunnel tunnel = Tunnel.build("localhost", talkFirstEchoServer.getServerSocketPort(),
        "localhost", proxyServer.getServerSocketPort());

    try {
      int tunnelPort = tunnel.getPort();
      SocketChannel client = SocketChannel.open();

      client.connect(new InetSocketAddress("localhost", tunnelPort));
      String response0 = readFromSocket(client);
      LOG.info(response0);

      // write a lot of data to increase chance of response after close
      for (int i = 0; i < 1000; i++) {
        client.write(ByteBuffer.wrap("Knock\n".getBytes()));
      }

      // don't wait for response
      client.close();

      assertEquals(response0, "Hello\n");
      assertEquals(proxyServer.getNumConnects(), 1);
    } finally {
      proxyServer.stopServer();
      tunnel.close();
      assertFalse(tunnel.isTunnelThreadAlive());
    }
  }

  @Test(timeOut = 15000, expectedExceptions = IOException.class)
  public void testTunnelThreadDeadAfterUnexpectedException() throws IOException, InterruptedException {
    MockServer proxyServer = startConnectProxyServer(false, false, 8);

    Tunnel tunnel = Tunnel.build("localhost", doubleEchoServer.getServerSocketPort(),
        "localhost", proxyServer.getServerSocketPort());

    String response = "";
    try {
      int tunnelPort = tunnel.getPort();
      SocketChannel client = SocketChannel.open();

      client.connect(new InetSocketAddress("localhost", tunnelPort));
      client.write(ByteBuffer.wrap("Knock\n".getBytes()));
      response = readFromSocket(client);
      LOG.info(response);

      for (int i = 0; i < 5; i++) {
        client.write(ByteBuffer.wrap("Hello\n".getBytes()));
        Thread.sleep(100);
      }
      client.close();
    } finally {
      proxyServer.stopServer();
      tunnel.close();
      assertNotEquals(response, "Knock Knock\n");
      assertEquals(proxyServer.getNumConnects(), 1);
      assertFalse(tunnel.isTunnelThreadAlive());
    }
  }

  /**
   * This test demonstrates connecting to a mysql DB through
   * and http proxy tunnel to a public data set of genetic data
   * http://www.ensembl.org/info/data/mysql.html
   *
   * Disabled for now because it requires the inclusion of a mysql jdbc driver jar
   *
   * @throws Exception
   */
  @Test(enabled = false, timeOut = 40000)
  public void accessEnsembleDB() throws Exception{
    MockServer proxyServer = startConnectProxyServer();
    Tunnel tunnel = Tunnel.build("useastdb.ensembl.org", 5306,
        "localhost", proxyServer.getServerSocketPort());

    try {
      int port = tunnel.getPort();

      Connection connection =
          DriverManager.getConnection("jdbc:mysql://localhost:" + port + "/homo_sapiens_core_82_38?user=anonymous");
      String query2 = "SELECT DISTINCT gene_id, biotype, source, description from gene LIMIT 1000";

      ResultSet resultSet = connection.createStatement().executeQuery(query2);

      int row = 0;

      while (resultSet.next()) {
        row++;
        LOG.info(String.format("%s|%s|%s|%s|%s%n", row, resultSet.getString(1), resultSet.getString(2), resultSet.getString(3),
            resultSet.getString(4)));

      }
      assertEquals(row, 1000);
      assertTrue(proxyServer.getNumConnects() > 0);
    }
    finally {
      proxyServer.stopServer();
      tunnel.close();
      assertFalse(tunnel.isTunnelThreadAlive());
    }
  }

}