[tcpdump-workers] BPF Extended: addressing BPF's shortcomings

Paul "LeoNerd" Evans leonerd at leonerd.org.uk
Thu Jun 11 05:37:54 EDT 2015


On Wed, 10 Jun 2015 19:25:58 -0700
Guy Harris <guy at alum.mit.edu> wrote:

> ...with some way of preventing infinite loops in the kernel, even if
> it's as crude as "there's a pointer into the packet and  if you do a
> backwards jump without moving that pointer forwards and checking to
> make sure you haven't gone beyond the end of the packet, the filter
> program immediately fails".  (Yes, that means it's no longer
> Turing-complete, as there's no longer a halting problem. :-))

That's exactly what my LOOP instruction suggestion does.

-- 
Paul "LeoNerd" Evans

leonerd at leonerd.org.uk
http://www.leonerd.org.uk/  |  https://metacpan.org/author/PEVANS


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