Hey Thomas,
In DPDK test cases, I agree that nothing other than Ethernet link types are 
currently used. However, when using DPDK Rawdev, the protocol is not usually 
Ethernet. In my case, I am trying to create PCAP files based on custom PCI-e 
traffic. The DPDK pcapng library currently hardcodes the metadata to be 
Ethernet, which cannot be read properly by Wireshark. Allowing the user to 
specify the protocol link type, the user can ensure the pcapng metadata matches 
the traffic data.
Dylan
________________________________
From: Thomas Monjalon <[email protected]>
Sent: Saturday, September 27, 2025 3:28 AM
To: Dylan Schneider <[email protected]>
Cc: [email protected] <[email protected]>; Reshma Pattan <[email protected]>; Jerin 
Jacob <[email protected]>; Kiran Kumar K <[email protected]>; Nithin 
Dabilpuram <[email protected]>; Zhirun Yan <[email protected]>; 
Stephen Hemminger <[email protected]>
Subject: Re: [PATCH v2] pcapng: allow any protocol link type for the interface 
block

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26/09/2025 02:04, Stephen Hemminger:
> On Wed, 27 Aug 2025 16:32:15 -0600
> Schneide <[email protected]> wrote:
>
> >
> > +* pcapng: Changed the API for adding interfaces to include a link type 
> > argument.
> > +  The link type was previously hardcoded to the ethernet link type in the 
> > API.
> > +  This argument is added to ``rte_pcapng_add_interface``.
> > +  These functions are versioned to retain binary compatibility until the 
> > next LTS release.
>
> Since link connector is now merged, and that wording might overlap and
> be confusing. Would be could to add reference to pcap-linktype.7 man
> page.

I'm not sure it overlaps.
RTE_ETH_LINK_CONNECTOR is about Ethernet cables while
pcap link type will be simply Ethernet type.

This being said, I don't understand the immediate benefit of this commit.
Why pcap link type would not be always Ethernet in DPDK case?
I think the only benefit is for future if other link types are added.
Is there something else I'm missing?


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