fake MAC addresses and ARP

[Bruce M. Simpson]

Some ideas:

1. Enable IFF_STATICARP on your interface to stop ARP sending out to 
resolve the IP/MAC address tuple.

2. Consider that you can deal with resolution in userland (RTF_RESOLVE) 
but this involves changing the net's entry (route) in the FTE. You'd 
then process RTM_RESOLVE messages and install routes yourself -- it's 
possible to do arp in userland with this.

3. Try to avoid using the 169.254.0.0/16 prefix as it has a specific 
meaning. We don't implement interface scoping for these addresses yet so 
the FTE can't deal with them appearing more than once for the same 
subnet; it may be easier to pick something else -- note that if ARP is 
enabled for an interface with one of these addresses, all ARP traffic is 
forced to be broadcast as per the zeroconf RFCs.

BMS