ore flags which are used to configure the behavior
    of a tunnel device.

    @cvar IFF_TUN: This indicates a I{tun}-type device.  This type of tunnel
        carries IP datagrams.  This flag is mutually exclusive with C{IFF_TAP}.

    @cvar IFF_TAP: This indicates a I{tap}-type device.  This type of tunnel
        carries ethernet frames.  This flag is mutually exclusive with C{IFF_TUN}.

    @cvar IFF_NO_PI: This indicates the I{protocol information} header will
        B{not} be included in data read from the tunnel.

    @see: U{https://www.kernel.org/doc/Documentation/networking/tuntap.txt}
    é