I have lengthened sockaddr_dl so that it can accomodate a FireWire
address.  That doesn't break any user<->kernel ABI, however, a number
of people have pointed out to me that it 3rd-party programs may rely on
sockaddr_dl's size remaining the same.  I am going to return sockaddr_dl
to its historical size, and introduce sockaddr_link for the kernel to use.
The address family (sa_family) of both sockaddr_dl and sockaddr_link
remain the same (AF_LINK).  I am also going to introduce macros CSLADDR()
and SLADDR() whose function is analogous to CLLADDR() and LLADDR().
I will rename all of the sockaddr_dl_*() routines in the kernel to
sockaddr_link_*().  Please let me know if this is going to break your
mother's back, make your cereal soggy, or stop your WiFi from working.

Dave

-- 
David Young             OJC Technologies
dyoung@ojctech.com      Urbana, IL * (217) 278-3933 ext 24