Re: [RFC] Addition of link-layer header types for PCI, PCI-X, and PCI-Express

[Aki Van Ness via tcpdump-workers <tcpdump-workers () lists tcpdump org>]

> --- Begin Message ---
>
>
> From: Aki Van Ness <aki.vanness () gmail com>
>
> Date: Fri, 23 Oct 2020 14:19:34 -0400
>
> On Thu, Oct 22, 2020 at 7:38 PM Michael Richardson <mcr () sandelman ca> wrote:
> > Aki Van Ness via tcpdump-workers <tcpdump-workers () lists tcpdump org> wrote:
> >     > I'm working on a project that plans to store PCI and PCI-Express
> >     > packets in the pcapng format as that's the most appropriate storage
> >     > format and I really rather not roll something custom.
> >
> >     > As such what are thoughts on adding Link-Layer types for PCI, PCI-X,
> >     > and PCI-Express?
> >
> > Yes, you could do that.
> > pcapng can handle a mix of different DLTs
> > (pcap can not).
> >
> > It seems that they might be sufficiently similar that a single DLT might suit
> > you.   Maybe you just want to build a header that accomodates a typical set
> > of meta data.
> >
> > I imagine you'd have things like: PCI cycle type (read, write, configuration,
> > IO, memory), read/write, address, any burst count, who is mastering, etc.
> >
> > The bulk of the content would be data transfered.
>
> Yeah it might be possible to use something like a single DLT. The
> issue I can possibly forsee with that is PCI, PCI-X, and PCI-Express
> are all slightly different enough to be a pain to group together into
> a single structure.
>
> It might be better to have either each type be its own DLT or if it
> must be one DLT a layered approach with a meta-header of sorts that
> just describes some of the generic information about
> the link, like it's type, etc. then have a sub-section whose
> interpretation is dependent on the link type.
>
> I'm more partial towards the former than the latter personally, but I
> understand not wanting to add a bunch of DLTs at once.
>
> >     > And would you want to group all versions of PCI, PCI-X, and
> >     > PCI-Express together or have them be their own values?
> >
> > --
> > ]               Never tell me the odds!                 | ipv6 mesh networks [
> > ]   Michael Richardson, Sandelman Software Works        |    IoT architect   [
> > ]     mcr () sandelman ca  http://www.sandelman.ca/        |   ruby on rails    [
>
> --- End Message ---
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