[dns-operations] Open source release of the DNS-STATS Compactor

Robert Edmonds edmonds at mycre.ws
Wed Jun 21 16:28:12 UTC 2017

Jim Hague wrote:
> Yes, I did verify that it's not a libtins problem. I reproduced the
> problem with a small libpcap-only program. However, I think that it is
> in fact a kernel problem rather than libpcap.
> Also, it's only a problem when using pacp_next()/pcap_next_ex() or
> pcap_dispatch(). It doesn't manifest with pcap_loop(), which is why I
> think tcpdump works.

Hi, Jim:

Any chance you could share that libpcap test program? That sounds like a
pretty serious bug. The Debian Jessie release is still supported by the
Debian project, so if that problem is due to a kernel or libpcap bug it
would be nice to get it fixed in an update.

> My notes indicate that upgrading to a backported Xenial kernel fixed the
> problem. I see that 14.04.5 installs with kernel 4.4.0 (which is the
> Xenial kernel) rather than the 13.13 from older 14.04.

"4.4.0" isn't really the upstream kernel version the Ubuntu kernel image
is based on. (I think for historic reasons related to the Linux 2 -> 3
version scheme change Ubuntu ends up having to zero out the last
component of the version embedded in the package name for some reason.)

If you need to know which upstream kernel a Debian/Ubuntu kernel image
is based on, you have to read the distro changelog (usually installed
locally somewhere like /usr/share/doc/linux-[...]/changelog.Debian.gz).
The upstream merges should be clearly labelled (e.g. "Xenial update to
4.4.67 stable release").

Robert Edmonds

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