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

loSsh1 = createobject("CkSsh")

// Connect directly to the 1st SSH server.
llSuccess = loSsh1.Connect("serverssh1.com",22)
if (llSuccess <> .T.) then
    ? loSsh1.LastErrorText
    release loSsh1
    return
endif

// Authenticate using login/password:
llSuccess = loSsh1.AuthenticatePw("ssh1Login","ssh1Password")
if (llSuccess <> .T.) then
    ? loSsh1.LastErrorText
    release loSsh1
    return
endif

// 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.
loSsh2 = createobject("CkSsh")
llSuccess = loSsh2.ConnectThroughSsh(loSsh1,"serverssh2.com",22)
if (llSuccess <> .T.) then
    ? loSsh2.LastErrorText
    release loSsh1
    release loSsh2
    return
endif

// Authenticate with ssh2...
llSuccess = loSsh2.AuthenticatePw("ssh2Login","ssh2Password")
if (llSuccess <> .T.) then
    ? loSsh2.LastErrorText
    release loSsh1
    release loSsh2
    return
endif

loSocket = createobject("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
llSuccess = loSocket.UseSsh(loSsh2)
if (llSuccess <> .T.) then
    ? loSocket.LastErrorText
    release loSsh1
    release loSsh2
    release loSocket
    return
endif

// Connect using TLS to www.chilkatsoft.com
// We could also tunnel a bare TCP connection by specifying port 80 with useTls = .F..
llUseTls = .T.
lnMaxWaitMillisec = 20000
llSuccess = loSocket.Connect("www.chilkatsoft.com",443,llUseTls,lnMaxWaitMillisec)
if (llSuccess <> .T.) then
    ? loSocket.LastErrorText
    release loSsh1
    release loSsh2
    release loSocket
    return
endif

// 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.
loSocket.StringCharset = "utf-8"

// Send an HTTP HEAD request:
llSuccess = loSocket.SendString("HEAD / HTTP/1.1" + Chr(13) + Chr(10) + "Host: www.chilkatsoft.com" + Chr(13) + Chr(10) + Chr(13) + Chr(10))
if (llSuccess <> .T.) then
    ? loSocket.LastErrorText
    release loSsh1
    release loSsh2
    release loSocket
    return
endif

// Wait a maximum of 4 seconds while no data is forthcoming:
loSocket.MaxReadIdleMs = 4000

// Get the 1st response line, which should be "HTTP/1.1 200 OK"
lcResponseStatusLine = loSocket.ReceiveToCRLF()
if (loSocket.LastMethodSuccess <> .T.) then
    ? loSocket.LastErrorText
    release loSsh1
    release loSsh2
    release loSocket
    return
endif

? "StatusLine: " + lcResponseStatusLine

// Now get the 1st line of the response header:
lcResponseHeaderLine = loSocket.ReceiveToCRLF()
if (loSocket.LastMethodSuccess <> .T.) then
    ? loSocket.LastErrorText
    release loSsh1
    release loSsh2
    release loSocket
    return
endif

? "HeaderLine: " + lcResponseHeaderLine

// Now read the remainder of the response header by reading until a double CRLF is seen:
lcRemainderOfHeader = loSocket.ReceiveUntilMatch(Chr(13) + Chr(10) + Chr(13) + Chr(10))
if (loSocket.LastMethodSuccess <> .T.) then
    ? loSocket.LastErrorText
    release loSsh1
    release loSsh2
    release loSocket
    return
endif

? "Remainder: " + lcRemainderOfHeader

// Close the connection with the server.  This closes the tunnel through ssh2.
// Wait a max of 20 seconds (20000 millsec)
llSuccess = loSocket.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.
loSsh2.Disconnect()

loSsh1.Disconnect()


release loSsh1
release loSsh2
release loSocket