On Thu, 23 Aug 2007, David Young wrote:
> A third-party program might abuse sockaddr_dl by embedding it into a
> wire format and assuming a fixed length.  [...]
> A hypothetical 3rd-party program that reads/writes AF_LINK sockaddrs
> from/to the kernel, today, and that assumes AF_LINK sockaddrs of fixed
> length, has always been broken.  It will remain broken.  However,
> a hypothetical 3rd-party program that sends/receives AF_LINK sockaddrs
> of fixed length to/from instances of itself will not break, because we
> will not change the length of sockaddr_dl.
> 
> Does that answer your question?

Yes, everything except why we should care so much about pandering to
broken applications.

--apb (Alan Barrett)