Visual FoxPro

TCP or TLS over Multiple Hop SSH to Remote Server

See more Socket/SSL/TLS Examples

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.

Visual FoxPro

LOCAL lnSuccess
LOCAL loSsh1
LOCAL loSsh2
LOCAL loSocket
LOCAL lnUseTls
LOCAL lnMaxWaitMillisec
LOCAL lcResponseStatusLine
LOCAL lcResponseHeaderLine
LOCAL lcRemainderOfHeader

lnSuccess = 0

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

loSsh1 = CreateObject('Chilkat.Ssh')

* Connect directly to the 1st SSH server.
lnSuccess = loSsh1.Connect("serverssh1.com",22)
IF (lnSuccess <> 1) THEN
    ? loSsh1.LastErrorText
    RELEASE loSsh1
    CANCEL
ENDIF

* Authenticate using login/password:
lnSuccess = loSsh1.AuthenticatePw("ssh1Login","ssh1Password")
IF (lnSuccess <> 1) THEN
    ? loSsh1.LastErrorText
    RELEASE loSsh1
    CANCEL
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('Chilkat.Ssh')
lnSuccess = loSsh2.ConnectThroughSsh(loSsh1,"serverssh2.com",22)
IF (lnSuccess <> 1) THEN
    ? loSsh2.LastErrorText
    RELEASE loSsh1
    RELEASE loSsh2
    CANCEL
ENDIF

* Authenticate with ssh2...
lnSuccess = loSsh2.AuthenticatePw("ssh2Login","ssh2Password")
IF (lnSuccess <> 1) THEN
    ? loSsh2.LastErrorText
    RELEASE loSsh1
    RELEASE loSsh2
    CANCEL
ENDIF

loSocket = CreateObject('Chilkat.Socket')

* 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
lnSuccess = loSocket.UseSsh(loSsh2)
IF (lnSuccess <> 1) THEN
    ? loSocket.LastErrorText
    RELEASE loSsh1
    RELEASE loSsh2
    RELEASE loSocket
    CANCEL
ENDIF

* Connect using TLS to www.chilkatsoft.com
* We could also tunnel a bare TCP connection by specifying port 80 with useTls = 0.
lnUseTls = 1
lnMaxWaitMillisec = 20000
lnSuccess = loSocket.Connect("www.chilkatsoft.com",443,lnUseTls,lnMaxWaitMillisec)
IF (lnSuccess <> 1) THEN
    ? loSocket.LastErrorText
    RELEASE loSsh1
    RELEASE loSsh2
    RELEASE loSocket
    CANCEL
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:
lnSuccess = loSocket.SendString("HEAD / HTTP/1.1" + CHR(13) + CHR(10) + "Host: www.chilkatsoft.com" + CHR(13) + CHR(10) + CHR(13) + CHR(10))
IF (lnSuccess <> 1) THEN
    ? loSocket.LastErrorText
    RELEASE loSsh1
    RELEASE loSsh2
    RELEASE loSocket
    CANCEL
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 <> 1) THEN
    ? loSocket.LastErrorText
    RELEASE loSsh1
    RELEASE loSsh2
    RELEASE loSocket
    CANCEL
ENDIF

? "StatusLine: " + lcResponseStatusLine

* Now get the 1st line of the response header:
lcResponseHeaderLine = loSocket.ReceiveToCRLF()
IF (loSocket.LastMethodSuccess <> 1) THEN
    ? loSocket.LastErrorText
    RELEASE loSsh1
    RELEASE loSsh2
    RELEASE loSocket
    CANCEL
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 <> 1) THEN
    ? loSocket.LastErrorText
    RELEASE loSsh1
    RELEASE loSsh2
    RELEASE loSocket
    CANCEL
ENDIF

? "Remainder: " + lcRemainderOfHeader

* Close the connection with the server.  This closes the tunnel through ssh2.
* Wait a max of 20 seconds (20000 millsec)
lnSuccess = 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