Re: Regarding User Data in DPDK ACL Library.

[venkatesh bs <venki.bsv@gmail.com>]

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Hi  konstantin, @stephen@networkplumber.org <stephen@networkplumber.org>

Thanks for the reply and your suggestions. I will try to see what can best
fit into my application.

Thanks & Regards,
Venkatesh.


On Fri, Nov 18, 2022 at 4:01 PM Konstantin Ananyev <
konstantin.ananyev@huawei.com> wrote:

>
>
> > On Thu, 17 Nov 2022 19:28:12 +0530
> > venkatesh bs <venki.bsv@gmail.com> wrote:
> >
> > > Hi DPDK Team,
> > >
> > > After the ACL match for highest priority DPDK Classification API
> returns
> > > User Data Which is as mentioned below in the document.
> > >
> > > 53. Packet Classification and Access Control — Data Plane Development
> Kit
> > > 22.11.0-rc2 documentation (dpdk.org)
> > >
> > >
> > >    - *userdata*: A user-defined value. For each category, a successful
> > >    match returns the userdata field of the highest priority matched
> rule. When
> > >    no rules match, returned value is zero
> > >
> > > I Wonder Why User Data Support does not returns 64 bit values,
>
> As I remember if first version of ACL code it was something about space
> savings
> to improve performance...
> Now I think it is more just a historical reason.
> It would be good to change userdata to 64bit, but I presume it will be ABI
> breakage.
>
> > Always its
> > > possible that User Data in Application Can be 64bit long, But since 64
> bit
> > > User data can't be returned by DPDK ACL Library, Application should
> have
> > > the conversion algorithm from 64 to 32 bit during Rule add and vice
> versa
> > > after classification.
> > >
> > > I Wonder if anyone would have faced this issue, Please suggest any
> > > suggestions if somewhere am wrong in understanding/Possible Solution if
> > > someone has already gone through this issue.
> > >
> > > Thanks In Advance.
> > > Regards,
> > > Venkatesh B Siddappa.
> >
> > It looks like all users of this API use the userdata to be the index
> > into a table of application specific rules.
>
> Yes, that's the most common way.
> Another one would be always (build/search) acl rules with two categories:
> rule for both categories will be identical, while data different (low/ho
> 32bits),
> but that's a bit too awkward from my perspective.
>
>
>
>
>

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