Re: After invoking pcap_compile 15 times I get "too many registers needed to evaluate expression"

[Thomas King <king () t-king de>]

On Friday 26 October 2007 02:50:15 am you wrote:
> On Oct 24, 2007, at 8:44 AM, Thomas King wrote:
> > I use libpcap 0.9.7 as provided by openSuSE 10.3. The problem I face
> > is
> > exemplified in the source code I attached to this email. The source
> > code is
> > an artificially created example to pin-point the problem I have.
> > Everything
> > works create until pcap_compile is invoked the 15th times. As I call
> > pcap_freecode at the end of each loop I would assume that the filter
> > memory
> > should be freed.
>
> The registers in question aren't filter-memory resources; the BPF
> pseudo-machine has 16 scratch memory locations, and if the code
> generator runs out of scratch memory locations, it fails with that
> error.
>
> > What is wrong with my program? Or is this a bug in libpcap?
>
> It's a bug in libpcap.  I've checked in a fix.  (It should only show
> up if you're capturing from a device that supplies radiotap headers or
> if you're reading from a capture file with radiotap headers.)
Thank you for your fast help!

> BTW, you can (and perhaps should) call pcap_freecode() after calling
> pcap_setfilter() - pcap_setfilter() makes a copy of the filter if
> necessary, so the original filter can be freed.
Thanks for the hint!

Best regards,
Thomas
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