Subject: Re: Implementing interface media type autodetection?
To: None <tech-net@NetBSD.ORG>
From: der Mouse <mouse@Collatz.McRCIM.McGill.EDU>
List: tech-net
Date: 06/09/1996 13:36:10
> [...] the link* flags as they are.  If they are used as a binary
> state indicator, we've got 8 possible states to play with, which will
> be more than enough for most interfaces, but will never be enough for
> all.  Adding a "link3" would probably [...]

Unfortunately adding another IFF_ flag bit requires an interface
change.  Fortunately it's a relatively small interface change.

The problem is that in the struct ifreq and struct if and related
places, the flags field is a short.  And all 16 of its bits are in use.

I've promoted that field to an int (I wanted another flag bit for a
completely different reason), and haven't seen any trouble short of, of
course, needing to recompile everything.  (And having a bit of a flag
day, since before-and-after kernels and userlands are compatible in
neither direction.)

					der Mouse