(Go) 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.

Chilkat Go Downloads Go Package for Windows, MacOS, Linux, Alpine Linux, Solaris

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

    ssh1 := chilkat.NewSsh()

    // Connect directly to the 1st SSH server.
    success := ssh1.Connect("serverssh1.com",22)
    if success != true {
        fmt.Println(ssh1.LastErrorText())
        ssh1.DisposeSsh()
        return
    }

    // Authenticate using login/password:
    success = ssh1.AuthenticatePw("ssh1Login","ssh1Password")
    if success != true {
        fmt.Println(ssh1.LastErrorText())
        ssh1.DisposeSsh()
        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.
    ssh2 := chilkat.NewSsh()
    success = ssh2.ConnectThroughSsh(ssh1,"serverssh2.com",22)
    if success != true {
        fmt.Println(ssh2.LastErrorText())
        ssh1.DisposeSsh()
        ssh2.DisposeSsh()
        return
    }

    // Authenticate with ssh2...
    success = ssh2.AuthenticatePw("ssh2Login","ssh2Password")
    if success != true {
        fmt.Println(ssh2.LastErrorText())
        ssh1.DisposeSsh()
        ssh2.DisposeSsh()
        return
    }

    socket := chilkat.NewSocket()

    // 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 {
        fmt.Println(socket.LastErrorText())
        ssh1.DisposeSsh()
        ssh2.DisposeSsh()
        socket.DisposeSocket()
        return
    }

    // Connect using TLS to www.chilkatsoft.com
    // We could also tunnel a bare TCP connection by specifying port 80 with useTls = false.
    useTls := true
    maxWaitMillisec := 20000
    success = socket.Connect("www.chilkatsoft.com",443,useTls,maxWaitMillisec)
    if success != true {
        fmt.Println(socket.LastErrorText())
        ssh1.DisposeSsh()
        ssh2.DisposeSsh()
        socket.DisposeSocket()
        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.SetStringCharset("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 {
        fmt.Println(socket.LastErrorText())
        ssh1.DisposeSsh()
        ssh2.DisposeSsh()
        socket.DisposeSocket()
        return
    }

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

    // Get the 1st response line, which should be "HTTP/1.1 200 OK"
    responseStatusLine := socket.ReceiveToCRLF()
    if socket.LastMethodSuccess() != true {
        fmt.Println(socket.LastErrorText())
        ssh1.DisposeSsh()
        ssh2.DisposeSsh()
        socket.DisposeSocket()
        return
    }

    fmt.Println("StatusLine: ", *responseStatusLine)

    // Now get the 1st line of the response header:
    responseHeaderLine := socket.ReceiveToCRLF()
    if socket.LastMethodSuccess() != true {
        fmt.Println(socket.LastErrorText())
        ssh1.DisposeSsh()
        ssh2.DisposeSsh()
        socket.DisposeSocket()
        return
    }

    fmt.Println("HeaderLine: ", *responseHeaderLine)

    // Now read the remainder of the response header by reading until a double CRLF is seen:
    remainderOfHeader := socket.ReceiveUntilMatch("\r\n\r\n")
    if socket.LastMethodSuccess() != true {
        fmt.Println(socket.LastErrorText())
        ssh1.DisposeSsh()
        ssh2.DisposeSsh()
        socket.DisposeSocket()
        return
    }

    fmt.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()

    ssh1.DisposeSsh()
    ssh2.DisposeSsh()
    socket.DisposeSocket()