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Re: if_flags

On Mon, Jan 26, 2009 at 04:42:55PM -0500, der Mouse wrote:
> >> How much of a pain would it be to grow [if_flags]?  struct ifnet is
> >> prepared for it; if_flags is 32-bit-aligned and the next field after
> >> it is a pad field.
> > As long as you add a second field, it should not be a problem.  If
> > you want to make if_flags itself 32bit, you have to deal with
> > endianess, don't you?
> I can't see why; if_flags doesn't appear anywhere where endianness is
> relevant as far as I know (no wire protocols, for example).  I didn't
> have any endianness issues when just growing the field on 1.4T, and I
> use hardware of each endianness regularly.  And if endianness mattered,
> wouldn't we have such issues today with the existing field, since it's
> already more than one byte?

I'd say it matters for binary compatibility.  However it's not that
important for ifnet anyway.  Exposing the new flags to userland will be
a different issue though, given the way ifreq works.

Quentin Garnier - -
"See the look on my face from staying too long in one place
[...] every time the morning breaks I know I'm closer to falling"
KT Tunstall, Saving My Face, Drastic Fantastic, 2007.

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