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Date:      Fri, 17 Jan 1997 00:06:14 +1100 (EST)
From:      proff@suburbia.net
To:        avalon@coombs.anu.edu.au (Darren Reed)
Cc:        hackers@freebsd.org
Subject:   Re: ipfw patches to test
Message-ID:  <19970116130614.8964.qmail@suburbia.net>
In-Reply-To: <no.id> from Darren Reed at "Jan 16, 97 11:10:20 pm"

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> To give you some idea of what I mean by this, when matching a packet
> through IP Filter, it does some preprocessing of the IP header(s) and
> matches src, dst, IP options (including security), ttl, tos, version,
> protocol, fragmented/not in 5 32bit mask-matches.  If you look at IP
> Filter now, you'll notice that it does all 5 of these without branching
> (whether it should or shouldn't branch early is dependant on CPU,
> especially instruction pipeline depth).

Cool. And on 64 bit arch you can of course do it in.. err 2.5 ;)

> btw, with the rmon fast packet matching with masks reference, were you
> alluding to the paper for one of the OSDI(?) conferences where they had
> benchmarked it at twice the speed of BPF ?
> 
> Darren

Don't recall reading the OSD paper, just noticed this technique in RMON source. Although I also read a bpf/fast mask comparison somewhere.

Cheers,
Julian <proff@iq.org>



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