rarp support

[Jay Soffian]

I have a patch against 2.0pl5 that adds rarp support. So far, it only 
works for Solaris, but it should be straightforward to make it work 
across all the platforms that are supported by dhcpd. I didn't want to 
hack on the internal code of dhcpd too much, so basically the patch 
listens for rarp requests and makes them look like bootp packets to the 
rest of the code. It then takes the bootp reply and unwraps back into a 
rarp reply.

If I updated this patch to work with the latest 3.x release candidate, 
made it work across platforms, and also added it the relay, would ISC 
consider this a useful addition? I don't want to go through all the 
trouble of bringing the patch forward if it won't get used.

Thanks.

j.