Kill off the static single net device and move to proper dynamic
registration (which we need with the new device model).
Break the (flawed) assumption that all network-layer protocols can use
ARP; such network-layer protocols (i.e. IPv4) must now register as an ARP
protocol using ARP_NET_PROTOCOL() and provide a single method for checking
the existence of a local network-layer address.
implementation allows for only one, and does so without compromising on
the efficiency of static allocation).
Link-layer protocols are cleanly separated from the device drivers.
Network-layer protocols are cleanly separated from individual network
devices.
Link-layer and network-layer protocols are cleanly separated from each
other.
