(Delphi DLL) SSH Tunnel Inside another SSH Tunnel

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

Chilkat for Delphi Downloads Chilkat non-ActiveX DLL for Delphi Chilkat ActiveX DLL for Delphi * The examples here use the non-ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, SshTunnel, CkDateTime, Socket;

...

procedure TForm1.Button1Click(Sender: TObject);
var
tunnel: HCkSshTunnel;
sshHostname: PWideChar;
sshPort: Integer;
success: Boolean;
tunnelB: HCkSocket;
channel: HCkSocket;
maxWaitMs: Integer;
useTls: Boolean;
bigEndian: Boolean;
dt: HCkDateTime;
bLocalTime: Boolean;
waitForThreadExit: Boolean;

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

// This example requires Chilkat version 9.5.0.50 or greater.
tunnel := CkSshTunnel_Create();

sshHostname := 'www.ssh-serverA.com';
sshPort := 22;

// Connect to an SSH server and establish the SSH tunnel:
success := CkSshTunnel_Connect(tunnel,sshHostname,sshPort);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkSshTunnel__lastErrorText(tunnel));
    Exit;
  end;

// Authenticate with the SSH server via a login/password
// or with a public key.  
// This example demonstrates SSH password authentication.
success := CkSshTunnel_AuthenticatePw(tunnel,'mySshLogin','mySshPassword');
if (success <> True) then
  begin
    Memo1.Lines.Add(CkSshTunnel__lastErrorText(tunnel));
    Exit;
  end;

// Indicate that the background SSH tunnel thread will behave as a SOCKS proxy server
// with dynamic port forwarding:
CkSshTunnel_putDynamicPortForwarding(tunnel,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.

CkSshTunnel_putInboundSocksUsername(tunnel,'chilkat123');
CkSshTunnel_putInboundSocksPassword(tunnel,'password123');

// Start the listen/accept thread to begin accepting SOCKS proxy client connections.
// Listen on port 1080.
success := CkSshTunnel_BeginAccepting(tunnel,1080);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkSshTunnel__lastErrorText(tunnel));
    Exit;
  end;

// 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.

tunnelB := CkSocket_Create();

// Indicate that the socket object is to use our portable SOCKS proxy/SSH tunnel running in our background thread.
CkSocket_putSocksHostname(tunnelB,'localhost');
CkSocket_putSocksPort(tunnelB,1080);
CkSocket_putSocksVersion(tunnelB,5);
CkSocket_putSocksUsername(tunnelB,'chilkat123');
CkSocket_putSocksPassword(tunnelB,'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 := CkSocket_SshOpenTunnel(tunnelB,'www.ssh-serverB.com',22);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkSocket__lastErrorText(tunnelB));
    Exit;
  end;

// Authenticate with ssh-serverB.com
success := CkSocket_SshAuthenticatePw(tunnelB,'uname','pwd');
if (success <> True) then
  begin
    Memo1.Lines.Add(CkSocket__lastErrorText(tunnelB));
    Exit;
  end;

// 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

maxWaitMs := 4000;
useTls := False;
channel := CkSocket_SshOpenChannel(tunnelB,'time-c.nist.gov',37,useTls,maxWaitMs);
if (CkSocket_getLastMethodSuccess(tunnelB) = False) then
  begin
    Memo1.Lines.Add(CkSocket__lastErrorText(tunnelB));
    Exit;
  end;

// 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.
bigEndian := True;
success := CkSocket_ReceiveInt32(channel,bigEndian);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkSocket__lastErrorText(channel));
    CkSocket_Dispose(channel);
    Exit;
  end;

dt := CkDateTime_Create();
CkDateTime_SetFromNtpTime(dt,CkSocket_getReceivedInt(channel));

// Show the current local date/time
bLocalTime := True;
Memo1.Lines.Add('Current local date/time: ' + CkDateTime__getAsRfc822(dt,bLocalTime));

// Close the SSH channel.
success := CkSocket_Close(channel,maxWaitMs);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkSocket__lastErrorText(channel));
    CkSocket_Dispose(channel);
    Exit;
  end;

CkSocket_Dispose(channel);

// Stop the background listen/accept thread:
waitForThreadExit := True;
success := CkSshTunnel_StopAccepting(tunnel,waitForThreadExit);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkSshTunnel__lastErrorText(tunnel));
    Exit;
  end;

// Close the SSH tunnel (would also kick any remaining connected clients).
success := CkSshTunnel_CloseTunnel(tunnel,waitForThreadExit);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkSshTunnel__lastErrorText(tunnel));
    Exit;
  end;

CkSshTunnel_Dispose(tunnel);
CkSocket_Dispose(tunnelB);
CkDateTime_Dispose(dt);

end;