[pf4freebsd] Re: Strange problem/Need help

[Max Laier]

On Sunday 25 July 2004 09:43, Hendrik Scholz wrote:
> Hi!
>
> Max Laier wrote:
> >  It turned out (after days of brainwracking debugging) that
> > the problem went away by disabling the i386 optimized version of
> > in4_cksum().
>
> Did you take into account that certain network cards do checksums in
> hardware?

Yes, we do account for that. In fact I did commit an improvement to the way we 
handle RXSUM from Pyun just before Christian had this fall out so my first 
though was, that I might have broken something with that commit. Turned out 
that this was not the case. Christian told me that doing the GCC update fixed 
the issue, btw. So I impute the whole issue to a compiler bug/issue or broken 
build environment.

> [0.27] hscholz at deimos:~ > ifconfig xl0
> xl0: flags=8802<BROADCAST,SIMPLEX,MULTICAST> mtu 1500
>          options=9<RXCSUM,VLAN_MTU>
>
> bge(4) and other good 10/100 and Gbit cards do even more so if the
> TXCSUM option is enabled bpf sees packets with broken checksums as these
> are calculated by the NIC itself before sending.

Even most of the xl(4) cards can do that, but due to broken hardware this is 
disabled since early this year.

-- 
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