SQL Server

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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-- Important: See this note about string length limitations for strings returned by sp_OAMethod calls.
--
CREATE PROCEDURE ChilkatSample
AS
BEGIN
    DECLARE @hr int
    DECLARE @iTmp0 int
    -- Important: Do not use nvarchar(max).  See the warning about using nvarchar(max).
    DECLARE @sTmp0 nvarchar(4000)
    DECLARE @success int
    SELECT @success = 0

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

    DECLARE @ssh1 int
    EXEC @hr = sp_OACreate 'Chilkat.Ssh', @ssh1 OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    -- Connect directly to the 1st SSH server.
    EXEC sp_OAMethod @ssh1, 'Connect', @success OUT, 'serverssh1.com', 22
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @ssh1, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @ssh1
        RETURN
      END

    -- Authenticate using login/password:
    EXEC sp_OAMethod @ssh1, 'AuthenticatePw', @success OUT, 'ssh1Login', 'ssh1Password'
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @ssh1, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @ssh1
        RETURN
      END

    -- 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.
    DECLARE @ssh2 int
    EXEC @hr = sp_OACreate 'Chilkat.Ssh', @ssh2 OUT

    EXEC sp_OAMethod @ssh2, 'ConnectThroughSsh', @success OUT, @ssh1, 'serverssh2.com', 22
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @ssh2, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @ssh1
        EXEC @hr = sp_OADestroy @ssh2
        RETURN
      END

    -- Authenticate with ssh2...
    EXEC sp_OAMethod @ssh2, 'AuthenticatePw', @success OUT, 'ssh2Login', 'ssh2Password'
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @ssh2, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @ssh1
        EXEC @hr = sp_OADestroy @ssh2
        RETURN
      END

    DECLARE @socket int
    EXEC @hr = sp_OACreate 'Chilkat.Socket', @socket OUT

    -- 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
    EXEC sp_OAMethod @socket, 'UseSsh', @success OUT, @ssh2
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @socket, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @ssh1
        EXEC @hr = sp_OADestroy @ssh2
        EXEC @hr = sp_OADestroy @socket
        RETURN
      END

    -- Connect using TLS to www.chilkatsoft.com
    -- We could also tunnel a bare TCP connection by specifying port 80 with useTls = 0.
    DECLARE @useTls int
    SELECT @useTls = 1
    DECLARE @maxWaitMillisec int
    SELECT @maxWaitMillisec = 20000
    EXEC sp_OAMethod @socket, 'Connect', @success OUT, 'www.chilkatsoft.com', 443, @useTls, @maxWaitMillisec
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @socket, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @ssh1
        EXEC @hr = sp_OADestroy @ssh2
        EXEC @hr = sp_OADestroy @socket
        RETURN
      END

    -- 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.
    EXEC sp_OASetProperty @socket, 'StringCharset', 'utf-8'

    -- Send an HTTP HEAD request:
    EXEC sp_OAMethod @socket, 'SendString', @success OUT, 'HEAD / HTTP/1.1' + CHAR(13) + CHAR(10) + 'Host: www.chilkatsoft.com' + CHAR(13) + CHAR(10) + CHAR(13) + CHAR(10)
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @socket, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @ssh1
        EXEC @hr = sp_OADestroy @ssh2
        EXEC @hr = sp_OADestroy @socket
        RETURN
      END

    -- Wait a maximum of 4 seconds while no data is forthcoming:
    EXEC sp_OASetProperty @socket, 'MaxReadIdleMs', 4000

    -- Get the 1st response line, which should be "HTTP/1.1 200 OK"
    DECLARE @responseStatusLine nvarchar(4000)
    EXEC sp_OAMethod @socket, 'ReceiveToCRLF', @responseStatusLine OUT
    EXEC sp_OAGetProperty @socket, 'LastMethodSuccess', @iTmp0 OUT
    IF @iTmp0 <> 1
      BEGIN
        EXEC sp_OAGetProperty @socket, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @ssh1
        EXEC @hr = sp_OADestroy @ssh2
        EXEC @hr = sp_OADestroy @socket
        RETURN
      END


    PRINT 'StatusLine: ' + @responseStatusLine

    -- Now get the 1st line of the response header:
    DECLARE @responseHeaderLine nvarchar(4000)
    EXEC sp_OAMethod @socket, 'ReceiveToCRLF', @responseHeaderLine OUT
    EXEC sp_OAGetProperty @socket, 'LastMethodSuccess', @iTmp0 OUT
    IF @iTmp0 <> 1
      BEGIN
        EXEC sp_OAGetProperty @socket, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @ssh1
        EXEC @hr = sp_OADestroy @ssh2
        EXEC @hr = sp_OADestroy @socket
        RETURN
      END


    PRINT 'HeaderLine: ' + @responseHeaderLine

    -- Now read the remainder of the response header by reading until a double CRLF is seen:
    DECLARE @remainderOfHeader nvarchar(4000)
    EXEC sp_OAMethod @socket, 'ReceiveUntilMatch', @remainderOfHeader OUT, CHAR(13) + CHAR(10) + CHAR(13) + CHAR(10)
    EXEC sp_OAGetProperty @socket, 'LastMethodSuccess', @iTmp0 OUT
    IF @iTmp0 <> 1
      BEGIN
        EXEC sp_OAGetProperty @socket, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @ssh1
        EXEC @hr = sp_OADestroy @ssh2
        EXEC @hr = sp_OADestroy @socket
        RETURN
      END


    PRINT 'Remainder: ' + @remainderOfHeader

    -- Close the connection with the server.  This closes the tunnel through ssh2.
    -- Wait a max of 20 seconds (20000 millsec)
    EXEC sp_OAMethod @socket, 'Close', @success OUT, 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.
    EXEC sp_OAMethod @ssh2, 'Disconnect', NULL

    EXEC sp_OAMethod @ssh1, 'Disconnect', NULL

    EXEC @hr = sp_OADestroy @ssh1
    EXEC @hr = sp_OADestroy @ssh2
    EXEC @hr = sp_OADestroy @socket


END
GO