(Lianja) 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.

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// 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.
loTunnel = createobject("CkSshTunnel")

lcSshHostname = "www.ssh-serverA.com"
lnSshPort = 22

// Connect to an SSH server and establish the SSH tunnel:
llSuccess = loTunnel.Connect(lcSshHostname,lnSshPort)
if (llSuccess <> .T.) then
    ? loTunnel.LastErrorText
    release loTunnel
    return
endif

// Authenticate with the SSH server via a login/password
// or with a public key.  
// This example demonstrates SSH password authentication.
llSuccess = loTunnel.AuthenticatePw("mySshLogin","mySshPassword")
if (llSuccess <> .T.) then
    ? loTunnel.LastErrorText
    release loTunnel
    return
endif

// Indicate that the background SSH tunnel thread will behave as a SOCKS proxy server
// with dynamic port forwarding:
loTunnel.DynamicPortForwarding = .T.

// 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.

loTunnel.InboundSocksUsername = "chilkat123"
loTunnel.InboundSocksPassword = "password123"

// Start the listen/accept thread to begin accepting SOCKS proxy client connections.
// Listen on port 1080.
llSuccess = loTunnel.BeginAccepting(1080)
if (llSuccess <> .T.) then
    ? loTunnel.LastErrorText
    release loTunnel
    return
endif

// 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.

loTunnelB = createobject("CkSocket")

// Indicate that the socket object is to use our portable SOCKS proxy/SSH tunnel running in our background thread.
loTunnelB.SocksHostname = "localhost"
loTunnelB.SocksPort = 1080
loTunnelB.SocksVersion = 5
loTunnelB.SocksUsername = "chilkat123"
loTunnelB.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).
llSuccess = loTunnelB.SshOpenTunnel("www.ssh-serverB.com",22)
if (llSuccess <> .T.) then
    ? loTunnelB.LastErrorText
    release loTunnel
    release loTunnelB
    return
endif

// Authenticate with ssh-serverB.com
llSuccess = loTunnelB.SshAuthenticatePw("uname","pwd")
if (llSuccess <> .T.) then
    ? loTunnelB.LastErrorText
    release loTunnel
    release loTunnelB
    return
endif

// 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

lnMaxWaitMs = 4000
llUseTls = .F.
loChannel = loTunnelB.SshOpenChannel("time-c.nist.gov",37,llUseTls,lnMaxWaitMs)
if (loTunnelB.LastMethodSuccess = .F.) then
    ? loTunnelB.LastErrorText
    release loTunnel
    release loTunnelB
    return
endif

// 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
// .T. or .F. to indicate success.  If successful, the integer
// is obtained via the ReceivedInt property.
llBigEndian = .T.
llSuccess = loChannel.ReceiveInt32(llBigEndian)
if (llSuccess <> .T.) then
    ? loChannel.LastErrorText
    release loChannel
    release loTunnel
    release loTunnelB
    return
endif

loDt = createobject("CkDateTime")
loDt.SetFromNtpTime(loChannel.ReceivedInt)

// Show the current local date/time
llBLocalTime = .T.
? "Current local date/time: " + loDt.GetAsRfc822(llBLocalTime)

// Close the SSH channel.
llSuccess = loChannel.Close(lnMaxWaitMs)
if (llSuccess <> .T.) then
    ? loChannel.LastErrorText
    release loChannel
    release loTunnel
    release loTunnelB
    release loDt
    return
endif

release loChannel

// Stop the background listen/accept thread:
llWaitForThreadExit = .T.
llSuccess = loTunnel.StopAccepting(llWaitForThreadExit)
if (llSuccess <> .T.) then
    ? loTunnel.LastErrorText
    release loTunnel
    release loTunnelB
    release loDt
    return
endif

// Close the SSH tunnel (would also kick any remaining connected clients).
llSuccess = loTunnel.CloseTunnel(llWaitForThreadExit)
if (llSuccess <> .T.) then
    ? loTunnel.LastErrorText
    release loTunnel
    release loTunnelB
    release loDt
    return
endif



release loTunnel
release loTunnelB
release loDt