TODO

Code tidy up: reduce the number of global variables.

Add support for win32 link-layer send and receive.

Add support for Token Ring.

Find portable function to get interface MAC address.

Investigate response packets >60 bytes long, e.g. Windows 2003 Server and
some Cisco.

Add XML output format.

MPLS tag support.

Use the new libpcap 1.0 API functions pcap_create(), pcap_set_XXX(), 
pcap_activate() instead of the old pcap_open_live() once we can be sure that
all supported OSes use libpcap 1.0 or later.

Use source_mac rather than interface_mac in the pcap filter, as suggested by
Justin Keogh. This will allow arp-scan to receive packets with spoofed MAC
source addresses.

Add support for Cisco ISL VLANs in addition to 802.1Q VLANs. Suggested by
Daniel at commonexploits.

Modify the IEEE MAC/Vendor mapping code and scripts to cater for the
forthcoming OUI registry restructuring detailed in:
http://tools.ietf.org/html/draft-ieee-rac-oui-restructuring-01