Socket options KPI

[Elad Efrat <elad%NetBSD.org@localhost>]

Hi,

I have a patch to make a large portion of the network code use a new
"struct sockopt" (inspired by similar work done in FreeBSD, with input
from dyoung@ and yamt@) instead of passing socket options in mbufs.

The work is incomplete - although I think the majority of the code was
covered. I've been running it here for about a month or so, but I'm
putting it up for public review as it's unlikely I'll be able to test
all of the code paths affected by these changes, specifically in network 
stacks I don't use...

The diff is available online:

        http://www.netbsd.org/~elad/sockopt-20080118.diff

All comments are welcome. It's not planned on being committed anytime
soon (unless, of course, all feedback suggests otherwise), so take your
time carefully reviewing the changes if you're interested. :)

Thanks,

-e.