def packGlobal_tcpip_forward(peer):
    """
    Pack the data for tcpip forwarding.

    @param peer: A tuple of the (host, port) .
    @type peer: L{tuple}
    """
    (host, port) = peer
    return common.NS(host) + struct.pack('>L', port)

    Pack the data for tcpip forwarding.

    @param peer: A tuple of the (host, port) .
    @type peer: L{tuple}
    
stackoverflow/venv/lib/python3.6/site-packages/twisted/conch/ssh/forwarding.py