B4X

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.

B4X

Dim success As Boolean = False

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

Dim ssh1 As ChilkatSsh
ssh1.Initialize("ssh1")

'  Connect directly to the 1st SSH server.
success = ssh1.Connect("serverssh1.com", 22)
If success <> True Then
    Log(ssh1.LastErrorText)
    Return
End If


'  Authenticate using login/password:
success = ssh1.AuthenticatePw("ssh1Login", "ssh1Password")
If success <> True Then
    Log(ssh1.LastErrorText)
    Return
End If


'  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.
Dim ssh2 As ChilkatSsh
ssh2.Initialize("ssh2")
success = ssh2.ConnectThroughSsh(ssh1, "serverssh2.com", 22)
If success <> True Then
    Log(ssh2.LastErrorText)
    Return
End If


'  Authenticate with ssh2...
success = ssh2.AuthenticatePw("ssh2Login", "ssh2Password")
If success <> True Then
    Log(ssh2.LastErrorText)
    Return
End If


Dim socket As ChilkatSocket
socket.Initialize("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
success = socket.UseSsh(ssh2)
If success <> True Then
    Log(socket.LastErrorText)
    Return
End If


'  Connect using TLS to www.chilkatsoft.com
'  We could also tunnel a bare TCP connection by specifying port 80 with useTls = False.
Dim useTls As Boolean = True
Dim maxWaitMillisec As Int = 20000
success = socket.Connect("www.chilkatsoft.com", 443, useTls, maxWaitMillisec)
If success <> True Then
    Log(socket.LastErrorText)
    Return
End If


'  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.StringCharset = "utf-8"

'  Send an HTTP HEAD request:
success = socket.SendString("HEAD / HTTP/1.1" & Chr(13) & Chr(10) & "Host: www.chilkatsoft.com" & Chr(13) & Chr(10) & Chr(13) & Chr(10))
If success <> True Then
    Log(socket.LastErrorText)
    Return
End If


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

'  Get the 1st response line, which should be "HTTP/1.1 200 OK"
Dim responseStatusLine As String = socket.ReceiveToCRLF
If socket.LastMethodSuccess <> True Then
    Log(socket.LastErrorText)
    Return
End If


Log("StatusLine: " & responseStatusLine)

'  Now get the 1st line of the response header:
Dim responseHeaderLine As String = socket.ReceiveToCRLF
If socket.LastMethodSuccess <> True Then
    Log(socket.LastErrorText)
    Return
End If


Log("HeaderLine: " & responseHeaderLine)

'  Now read the remainder of the response header by reading until a double CRLF is seen:
Dim remainderOfHeader As String = socket.ReceiveUntilMatch(Chr(13) & Chr(10) & Chr(13) & Chr(10))
If socket.LastMethodSuccess <> True Then
    Log(socket.LastErrorText)
    Return
End If


Log("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