Re: TCPv4 checksum errors

[Martin Costabel <costabel@wanadoo.fr>]

Paul Mackerras wrote:
> 
> Geert Uytterhoeven <Geert.Uytterhoeven@cs.kuleuven.ac.be> wrote:
> 
> > There must be a bug left in the TCPv4 checksum code. Linux/PPC still sends
> > out packets with bad checksums. Any TCP checksum experts listening?
> 
> I have tried Dave Miller's checksum test program on the PPC inet
> checksum code and it didn't find any errors.  Do you have an example
> of a specific packet with a bad checksum generated by Linux/PPC?

I can get bad TCPv4 checksum errors very easily by telnetting to
dev.linuxppc.org. From /var/log/messages:

Dec 22 08:05:07 rennes-43 identd[19807]: Connection from
dev.linuxppc.org
Dec 22 08:05:12 rennes-43 identd[19807]: from: 169.207.161.2 (
dev.linuxppc.org ) for: 2526, 21
Dec 22 08:05:12 rennes-43 identd[19807]: Successful lookup: 2526 , 21 :
root.root 
Dec 22 08:05:52 rennes-43 kernel: TCPv4 bad checksum from
169.207.161.2:0017 to 193.252.125.43:09df, len=20/20/40
Dec 22 08:05:55 rennes-43 kernel: TCPv4 bad checksum from
169.207.161.2:0017 to 193.252.125.43:09df, len=20/20/40

Yesterday I got them also all the time while ftping from there. Today I
didn't see this.

--
Martin

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