Re: [long] "bad cksum 0!" on AIX 5 over loopback

[Shaun <delius () progsoc uts edu au>]

On Wed, 2 Jul 2003, Guy Harris wrote:

> On Wednesday, July 2, 2003, at 4:30 PM, Shaun wrote:
>
> > That one is a mystery, it appears to be some sort of kernel issue with
> > uiomove(), I tried to determine what was going on, but gave up when I
> > found that memset()ing the buffer to 0 before using it made the
> > problem go
> > away.
>
> Did that make it go away completely, or did it still occur on occasion?
>   The comment after "case EFAULT:" says

Yeah, I didn't want to be too definitive on that one, given that any
statement could only be based on my experience (not exactly scientifically
definitive). In any case, our internal version of pcap doesn't have the
restart logic (i.e will return an error if it happens) so as we continue
testing I can let you know. I certainly haven't seen it happen (at all)
since I made the memset change.

> > You should also note that the AIX bpf driver is buggy and may CRASH
> > YOUR
> > MACHINE, do not use it in production. IBM have recently fixed the
> > problems
> > and tell me a new version should be released around half way through
> > August.
>
> Have they fixed the EFAULT problem too?

Not sure, I'll have to get back to you on that one. (Though to be honest I
consider it good practice to clear buffers before I use them, so I'll
probably keep the memset in any case)

Cheers,
Shaun


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