On Fri, 12 Dec 2025 00:53:40 -0800
Guy Harris <[email protected]> wrote:

> > This would allow using tcpdump etc while running any of the many
> > DPDK routing, switch applications.
> > 
> > The question is should the new code:
> > be another capture type: i.e pcap-pdump; or just rewrite existing
> > code in pcap-dpdk?  
> 
> If it would do a better job of allowing programs to capture network
> traffic through a DPDK interface than the current code does (even if
> "better" just means "does an equally good job from the point of view
> of the program, but is easier to maintain"), then I'm not sure
> there's a reason to keep the old code around, just replace the
> existing code (even if the "rewrite" means "throw it away and start
> from scratch").

Yes.  How much of the existing code to preserve, if any, would be up to
anyone who can get pcap-dpdk.c into shape.

One of the directions of work done in libpcap in recent few years has
been removing of modules that could/should not be maintained anymore
(e.g. AirPcap, Enetfilter, NIT, Septel, STREAMS NIT, TurboCap and
[Tru64/Ultrix] Packet Filter).  Another was fixing of various bit rot
in the remaining modules where practicable (DAG, DLPI, Haiku, Hurd,
SNF).  In this sense DPDK support has not ended up as one of these two
cases yet.

> > Is there a maintainer for the DPDK code in libpcap?  
> 
> Not really. I don't know to what extent any of us core developers are
> sufficiently familiar to act as maintainers (I'm not).

pcap-dpdk.c has been in the source tree for 7 years, most of this time
barely maintained and originally developed for DPDK 18.11.  Existing
libpcap releases cannot build with DPDK newer than 22.11; Ido Goshen has
fixed that for the master branch in August 2025 and opened pull request
1547 with another improvement.  That said, as a matter of fact, DPDK
has not been an area of our collective expertise, so help in this
department would be welcome.

If you remember, I posted a message along those lines to [email protected]
in February 2025, at the time of this writing the invitation still
stands, but I am not subscribed to that mailing list now.

Stephen, you obviously know the DPDK side of the fence.  If you are
willing to make any improvements to pcap-dpdk.c, from a libpcap
maintainer point of view it would be useful to see the updated code:

* practicable to follow and to relate with DPDK documentation
* implementing libpcap semantics consistently with other libpcap
  modules
* obviously working in a basic common use case
* having an up to date README file

For now it would be best to make any such improvements in the master
branch only.  If everything goes well, in a few months the remaining
blockers for libpcap-1.11.0 will be resolved and the improvements will
be available in 1.11.0.  Any improvements after 1.11.0 would have to
be back-ported to libpcap-1.11 after the latter comes into existence,
but this would be fine.

If you need any additional information to decide, just ask.

-- 
    Denis Ovsienko
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