Subject: Re: lib/16518 (some fixes to libpcap)
To: None <M.Drochner@fz-juelich.de>
From: YAMAMOTO Takashi <firstname.lastname@example.org>
Date: 02/28/2006 08:18:45
> email@example.com said:
> > was not sure which of signed or unsigned should be used.
> For me it is pretty obvious that unsigned should be used,
> to be consistent with kernel behaviour. While the manpage
> doesn't tell, the kernel implementations are there and
> cannot be changed anymore, just documented.
to be consistent with kernel, yes. i thought so and made the patch.
i still support the "fix libpcap optimizer to match to kernel" way.
but if it's considered a kernel bug, we can fix kernel implementations, IMO.
> Optimization of "=" gets a bit further -- a call of
> tcpdump "(0x80000000 / 2) = 0x40000000"
> does yield
> tcpdump: expression rejects all packets
> tcpdump -O "(0x80000000 / 2) = 0x40000000"
> happily receives packets.
> Your patch fixes exactly these inconsistencies.
but, if it was "(-10)/2 == -5", one might think it's natural to
optimize it to TRUE, and consider it as a kernel bug.
given the lack of strict specification of the language, i couldn't say
which was correct.
> > i guess it's better to bring a discussion on tcpdump-workers again
> This might be a good idea. Do you want to defent your patch once more?
honestly speaking, i don't, as my memory about libpcap and
the patch is somewhat stale... i'm happy if you just beat me. :-)
> I'm just working on an update of NetBSD's libpcap to 0.9.4, and I plan
> to post the more essential changes to tcpdump-workers too.
> (Which is merely some "const" consistency for now, and support for
> the cloning /dev/bpf.)