Open opens the specified TUN device, sets it to non-blocking mode, and returns its file descriptor.

OpenTAP opens the specified TAP device, sets it to non-blocking mode, and returns its file descriptor.

PacketInfoHeaderSize is the size of the packet information header.

Device is an opened /dev/net/tun device.

Flags set properties of a Device +stateify savable.

PacketInfoFields contains fields sent through the wire if IFF_NO_PI flag is not set.

PacketInfoHeader is the wire representation of the packet information sent if IFF_NO_PI flag is not set.