Re: IPv4 kernel messages

Geert Uytterhoeven (Geert.Uytterhoeven@cs.kuleuven.ac.be)
Mon, 7 Sep 1998 16:47:23 +0200 (CEST)

On Sun, 6 Sep 1998, David S. Miller wrote:
> Date: Mon, 7 Sep 1998 01:12:16 +0200 (CEST)
> From: Geert Uytterhoeven <Geert.Uytterhoeven@cs.kuleuven.ac.be>
>
> They're still there:
>
> | Socket destroy delayed (r=0 w=160)
> | TCPv4 bad checksum from 10.0.24.8:0071 to 10.0.24.4:040c, len=20/20/40
>
> Are these just warnings to be disabled in 2.2, or is there something wrong?
>
> 10.0.24.4 runs Linux/m68k 2.1.119. 10.0.24.8 is a PPC running vger-19980903.
> I see them only rarely on my main workstation which talks a lot to the
> rest of the world. On my internal Linux-2.1.x machines I never see
> it.
>
> I would check out the csum routines on m68k and PPC to make sure they
> are sane in all cases.
>
> Here is the lifesaver development utility I have been using for a long
> time to verify all major changes made to Sparc and MIPS checksumming
> routines. It won't work for you as-is, but you can figure out what it
> is supposed to do and link the PPC and M68k csum routines into it to
> perform verifications. Note there is an ugly piece of MIPS inline asm
> in here which you'll need to remove too as the last thing I used this
> for was the Cobalt kernels :-) Note it also performs performance
> metrics on your code too, so it's useful for speed tuning as well as
> verification.

Thanks! The PPC checksumming code passed the test, but the m68k code seems to
be broken. I got:

verify_ip_fast_csum: buffer 0 gets bogus csum abe7!

Ulrik De Bie wrote:
> I think the following information is interesting here. I have the same with
> Linux/i486 running recent-vger and PPC running recent-vger.
>
> So both intel and m68k are wrong, or ppc is wrong. Which would give a big
> hint to the latter.

Since PPC passed the test, this would indicate that ia32 is incorrect, too.

But if I understand it correctly, the test isn't exhaustive, right?

Greetings,

Geert

P.S. I put the code I used (i.e. Dave's with adaptations for ppc and m68k) on
my webpage: http://www.cs.kuleuven.ac.be/~geert/bin/cksum_helper.c

--
Geert Uytterhoeven                     Geert.Uytterhoeven@cs.kuleuven.ac.be
Wavelets, Linux/{m68k~Amiga,PPC~CHRP}  http://www.cs.kuleuven.ac.be/~geert/
Department of Computer Science -- Katholieke Universiteit Leuven -- Belgium




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