TAILQ_FIRST(&ifp->if_addrhead) to find the link layer ifaddr.
(it's always first I believe)
Allows this to compile on -current.
.. need testers with FEC capable switches..
These are really only partly netgraph nodes as they do not use the
netgraph interfaces for many of the functions for which they could
be used, however they represent important functionality.
Submitted by: wpaul
MFC after: 2 days