(Java) TCP or TLS over Multiple Hop SSH to Remote Server

Demonstrates how to use the Chilkat Socket API to connect to a remote server (using TCP or TLS) tunneled through mulitple-hop SSH. The scheme looks like this:

Application => ServerSSH1 => ServerSSH2 => DestinationServer

The ConnectThroughSsh and UseSsh methods are added in Chilkat version 9.5.0.55 to accomplish this task.

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import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    CkSsh ssh1 = new CkSsh();

    // Connect directly to the 1st SSH server.
    boolean success = ssh1.Connect("serverssh1.com",22);
    if (success != true) {
        System.out.println(ssh1.lastErrorText());
        return;
        }

    // Authenticate using login/password:
    success = ssh1.AuthenticatePw("ssh1Login","ssh1Password");
    if (success != true) {
        System.out.println(ssh1.lastErrorText());
        return;
        }

    // Connect through the 1st SSH connection to reach a 2nd SSH server.
    // Note: Any number of SSH connections may be simultaneously tunneled through a single
    // existing SSH connection.
    CkSsh ssh2 = new CkSsh();
    success = ssh2.ConnectThroughSsh(ssh1,"serverssh2.com",22);
    if (success != true) {
        System.out.println(ssh2.lastErrorText());
        return;
        }

    // Authenticate with ssh2...
    success = ssh2.AuthenticatePw("ssh2Login","ssh2Password");
    if (success != true) {
        System.out.println(ssh2.lastErrorText());
        return;
        }

    CkSocket socket = new CkSocket();

    // Tell the socket object to connect to our destination server though the ssh2 tunnel (which itself is routed through ssh1).
    // The connection looks like this:  ApplicationSocket(TLS) => ServerSSH1 => ServerSSH2 => DestinationServer
    success = socket.UseSsh(ssh2);
    if (success != true) {
        System.out.println(socket.lastErrorText());
        return;
        }

    // Connect using TLS to www.chilkatsoft.com
    // We could also tunnel a bare TCP connection by specifying port 80 with useTls = false.
    boolean useTls = true;
    int maxWaitMillisec = 20000;
    success = socket.Connect("www.chilkatsoft.com",443,useTls,maxWaitMillisec);
    if (success != true) {
        System.out.println(socket.lastErrorText());
        return;
        }

    // Once the multiple hop SSH tunneled connection is setup,  the socket programming
    // is identical to the normal case where we have a direct connection.

    // Tell the socket object that all text is to be sent in the utf-8 encoding,
    // and the text received is assumed to be utf-8.
    socket.put_StringCharset("utf-8");

    // Send an HTTP HEAD request:
    success = socket.SendString("HEAD / HTTP/1.1\r\nHost: www.chilkatsoft.com\r\n\r\n");
    if (success != true) {
        System.out.println(socket.lastErrorText());
        return;
        }

    // Wait a maximum of 4 seconds while no data is forthcoming:
    socket.put_MaxReadIdleMs(4000);

    // Get the 1st response line, which should be "HTTP/1.1 200 OK"
    String responseStatusLine = socket.receiveToCRLF();
    if (socket.get_LastMethodSuccess() != true) {
        System.out.println(socket.lastErrorText());
        return;
        }

    System.out.println("StatusLine: " + responseStatusLine);

    // Now get the 1st line of the response header:
    String responseHeaderLine = socket.receiveToCRLF();
    if (socket.get_LastMethodSuccess() != true) {
        System.out.println(socket.lastErrorText());
        return;
        }

    System.out.println("HeaderLine: " + responseHeaderLine);

    // Now read the remainder of the response header by reading until a double CRLF is seen:
    String remainderOfHeader = socket.receiveUntilMatch("\r\n\r\n");
    if (socket.get_LastMethodSuccess() != true) {
        System.out.println(socket.lastErrorText());
        return;
        }

    System.out.println("Remainder: " + remainderOfHeader);

    // Close the connection with the server.  This closes the tunnel through ssh2.
    // Wait a max of 20 seconds (20000 millsec)
    success = socket.Close(20000);

    // Close the connection with ssh2.  (This closes the the tunnel through ssh1.)
    // The connection with ssh1 is still alive, and may be used for more connections.
    ssh2.Disconnect();

    ssh1.Disconnect();
  }
}