SQL Server

TCP Socket through SSH Tunnel (Port Forwarding)

See more Socket/SSL/TLS Examples

Demonstrates using Chilkat Socket to communicate to a TCP service through an SSH tunnel. This example will connect to an NIST time server and (using the old Time Protocol (RFC 868)), will read the current GMT time.

Note: This is not necessarily a recommended means for getting the current date/time. The most commonly used time protocol is the Network Time Protocol (RFC-1305). The intent of this example is to show how TCP communications can occur through an SSH tunnel.

SQL Server

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

    DECLARE @sshHostname nvarchar(4000)
    SELECT @sshHostname = 'sftp.example.com'
    DECLARE @sshPort int
    SELECT @sshPort = 22

    -- Connect to an SSH server and establish the SSH tunnel:
    EXEC sp_OAMethod @tunnel, 'SshOpenTunnel', @success OUT, @sshHostname, @sshPort
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @tunnel, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @tunnel
        RETURN
      END

    -- Authenticate with the SSH server via a login/password
    -- or with a public key.
    -- This example demonstrates SSH password authentication.
    EXEC sp_OAMethod @tunnel, 'SshAuthenticatePw', @success OUT, 'mySshLogin', 'mySshPassword'
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @tunnel, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @tunnel
        RETURN
      END

    -- OK, the SSH tunnel is setup.  Now open a channel within the tunnel.
    -- Once the channel is obtained, the Socket API may
    -- be used exactly the same as usual, except all communications
    -- are sent through the channel in the SSH tunnel.
    -- Any number of channels may be created from the same SSH tunnel.
    -- Multiple channels may coexist at the same time.

    -- Connect to an NIST time server and read the current date/time
    DECLARE @maxWaitMs int
    SELECT @maxWaitMs = 4000
    DECLARE @useTls int
    SELECT @useTls = 0
    DECLARE @channel int
    EXEC @hr = sp_OACreate 'Chilkat.Socket', @channel OUT

    EXEC sp_OAMethod @tunnel, 'SshNewChannel', @success OUT, 'time-c.nist.gov', 37, @useTls, @maxWaitMs, @channel
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @tunnel, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @tunnel
        EXEC @hr = sp_OADestroy @channel
        RETURN
      END

    -- The time server will send a big-endian 32-bit integer representing
    -- the number of seconds since since 00:00 (midnight) 1 January 1900 GMT.
    -- The ReceiveInt32 method will receive a 4-byte integer, but returns
    -- 1 or 0 to indicate success.  If successful, the integer
    -- is obtained via the ReceivedInt property.
    DECLARE @bigEndian int
    SELECT @bigEndian = 1
    EXEC sp_OAMethod @channel, 'ReceiveInt32', @success OUT, @bigEndian
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @channel, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @tunnel
        EXEC @hr = sp_OADestroy @channel
        RETURN
      END

    DECLARE @dt int
    EXEC @hr = sp_OACreate 'Chilkat.CkDateTime', @dt OUT

    EXEC sp_OAGetProperty @channel, 'ReceivedInt', @iTmp0 OUT
    EXEC sp_OAMethod @dt, 'SetFromNtpTime', @success OUT, @iTmp0

    -- Show the current local date/time
    DECLARE @bLocalTime int
    SELECT @bLocalTime = 1

    EXEC sp_OAMethod @dt, 'GetAsRfc822', @sTmp0 OUT, @bLocalTime
    PRINT 'Current local date/time: ' + @sTmp0

    -- Close the SSH channel.
    EXEC sp_OAMethod @channel, 'Close', @success OUT, @maxWaitMs
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @channel, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @tunnel
        EXEC @hr = sp_OADestroy @channel
        EXEC @hr = sp_OADestroy @dt
        RETURN
      END

    -- It is possible to create a new channel from the existing SSH tunnel for the next connection:
    -- Any number of channels may be created from the same SSH tunnel.
    -- Multiple channels may coexist at the same time.
    EXEC sp_OAMethod @tunnel, 'SshNewChannel', @success OUT, 'time-a.nist.gov', 37, @useTls, @maxWaitMs, @channel
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @tunnel, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @tunnel
        EXEC @hr = sp_OADestroy @channel
        EXEC @hr = sp_OADestroy @dt
        RETURN
      END

    -- Review the LastErrorText to see that the connection was made via the SSH tunnel:
    EXEC sp_OAGetProperty @tunnel, 'LastErrorText', @sTmp0 OUT
    PRINT @sTmp0

    -- Close the connection to time-a.nist.gov.  This is actually closing our channel
    -- within the SSH tunnel, but keeps the tunnel open for the next port-forwarded connection.
    EXEC sp_OAMethod @channel, 'Close', @success OUT, @maxWaitMs
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @channel, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @tunnel
        EXEC @hr = sp_OADestroy @channel
        EXEC @hr = sp_OADestroy @dt
        RETURN
      END

    -- Finally, close the SSH tunnel.
    EXEC sp_OAMethod @tunnel, 'SshCloseTunnel', @success OUT
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @tunnel, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @tunnel
        EXEC @hr = sp_OADestroy @channel
        EXEC @hr = sp_OADestroy @dt
        RETURN
      END


    PRINT 'TCP SSH tunneling example completed.'

    EXEC @hr = sp_OADestroy @tunnel
    EXEC @hr = sp_OADestroy @channel
    EXEC @hr = sp_OADestroy @dt


END
GO