Re: Regarding User Data in DPDK ACL Library.

[Stephen Hemminger <stephen@networkplumber.org>]

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, 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.