Android™

SSH Tunnel Inside another SSH Tunnel

See more SSH Tunnel Examples

Demonstrates how to create a TCP/IP socket connection through an SSH tunnel that is dynamic port forwarded through another SSH tunnel. Android™

// Important: Don't forget to include the call to System.loadLibrary
// as shown at the bottom of this code sample.
package com.test;

import android.app.Activity;
import com.chilkatsoft.*;

import android.widget.TextView;
import android.os.Bundle;

public class SimpleActivity extends Activity {

  private static final String TAG = "Chilkat";

  // Called when the activity is first created.
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    boolean success = false;

    //  This example requires the Chilkat API to have been previously unlocked.
    //  See Global Unlock Sample for sample code.

    CkSshTunnel tunnel = new CkSshTunnel();

    String sshHostname = "www.ssh-serverA.com";
    int sshPort = 22;

    //  Connect to an SSH server and establish the SSH tunnel:
    success = tunnel.Connect(sshHostname,sshPort);
    if (success == false) {
        Log.i(TAG, tunnel.lastErrorText());
        return;
        }

    //  Authenticate with the SSH server via a login/password
    //  or with a public key.  
    //  This example demonstrates SSH password authentication.
    success = tunnel.AuthenticatePw("mySshLogin","mySshPassword");
    if (success == false) {
        Log.i(TAG, tunnel.lastErrorText());
        return;
        }

    //  Indicate that the background SSH tunnel thread will behave as a SOCKS proxy server
    //  with dynamic port forwarding:
    tunnel.put_DynamicPortForwarding(true);

    //  We may optionally require that connecting clients authenticate with our SOCKS proxy server.
    //  To do this, set an inbound username/password.  Any connecting clients would be required to 
    //  use SOCKS5 with the correct username/password.
    //  If no inbound username/password is set, then our SOCKS proxy server will accept both
    //  SOCKS4 and SOCKS5 unauthenticated connections.

    tunnel.put_InboundSocksUsername("chilkat123");
    tunnel.put_InboundSocksPassword("password123");

    //  Start the listen/accept thread to begin accepting SOCKS proxy client connections.
    //  Listen on port 1080.
    success = tunnel.BeginAccepting(1080);
    if (success == false) {
        Log.i(TAG, tunnel.lastErrorText());
        return;
        }

    //  Now that a background thread is running a SOCKS proxy server that forwards connections
    //  through an SSH tunnel, it is possible to use any Chilkat implemented protocol that is SOCKS capable,
    //  such as HTTP, POP3, SMTP, IMAP, FTP, Socket, etc.  The protocol may use SSL/TLS because the SSL/TLS
    //  will be passed through the SSH tunnel to the end-destination.  Also, any number of simultaneous
    //  connections may be routed through the SSH tunnel.

    CkSocket tunnelB = new CkSocket();

    //  Indicate that the socket object is to use our portable SOCKS proxy/SSH tunnel running in our background thread.
    tunnelB.put_SocksHostname("localhost");
    tunnelB.put_SocksPort(1080);
    tunnelB.put_SocksVersion(5);
    tunnelB.put_SocksUsername("chilkat123");
    tunnelB.put_SocksPassword("password123");

    //  Open a new SSH tunnel through the existing tunnel (via what we treat as a SOCKS5 proxy,
    //  but it is actually a dynamic port-forwarded SSH tunnel).
    success = tunnelB.SshOpenTunnel("www.ssh-serverB.com",22);
    if (success == false) {
        Log.i(TAG, tunnelB.lastErrorText());
        return;
        }

    //  Authenticate with ssh-serverB.com
    success = tunnelB.SshAuthenticatePw("uname","pwd");
    if (success == false) {
        Log.i(TAG, tunnelB.lastErrorText());
        return;
        }

    //  OK, the SSH tunnel (within a tunnel) is setup.  Now open a channel within the tunnel.
    //  Once the channel is obtained, the Socket API may
    //  be used exactly the same as usual, except all communications
    //  are sent through the channel in the SSH tunnel.
    //  Any number of channels may be created from the same SSH tunnel.
    //  Multiple channels may coexist at the same time.

    //  Connect to an NIST time server and read the current date/time
    CkSocket channel = new CkSocket();
    int maxWaitMs = 4000;
    boolean useTls = false;
    success = tunnelB.SshNewChannel("time-c.nist.gov",37,useTls,maxWaitMs,channel);
    if (success == false) {
        Log.i(TAG, tunnelB.lastErrorText());
        return;
        }

    //  The time server will send a big-endian 32-bit integer representing
    //  the number of seconds since since 00:00 (midnight) 1 January 1900 GMT.
    //  The ReceiveInt32 method will receive a 4-byte integer, but returns
    //  true or false to indicate success.  If successful, the integer
    //  is obtained via the ReceivedInt property.
    boolean bigEndian = true;
    success = channel.ReceiveInt32(bigEndian);
    if (success == false) {
        Log.i(TAG, channel.lastErrorText());
        return;
        }

    CkDateTime dt = new CkDateTime();
    dt.SetFromNtpTime(channel.get_ReceivedInt());

    //  Show the current local date/time
    boolean bLocalTime = true;
    Log.i(TAG, "Current local date/time: " + dt.getAsRfc822(bLocalTime));

    //  Close the SSH channel.
    success = channel.Close(maxWaitMs);
    if (success == false) {
        Log.i(TAG, channel.lastErrorText());
        return;
        }

    //  Stop the background listen/accept thread:
    boolean waitForThreadExit = true;
    success = tunnel.StopAccepting(waitForThreadExit);
    if (success == false) {
        Log.i(TAG, tunnel.lastErrorText());
        return;
        }

    //  Close the SSH tunnel (would also kick any remaining connected clients).
    success = tunnel.CloseTunnel(waitForThreadExit);
    if (success == false) {
        Log.i(TAG, tunnel.lastErrorText());
        return;
        }


  }

  static {
      System.loadLibrary("chilkat");

      // Note: If the incorrect library name is passed to System.loadLibrary,
      // then you will see the following error message at application startup:
      //"The application <your-application-name> has stopped unexpectedly. Please try again."
  }
}