Re: [dpdk-dev] Working of pipeline in a given config file and regarding user-defined actions in IP_PIPELINE application

[Nidhia Varghese <nidhiavarghese93@gmail.com>]

Hi Christian,

Can you please elaborate on how to use DMA action of pass-through table for
this?

Is that like creating a separate pipeline for saving this metadata to the
headroom space and in the next pipeline we use this metadata field for
further lookups. And we will be using different keys for each of these
pipelines. Is that so?

Thanks for your help.

Nidhia

On Tue, Apr 11, 2017 at 2:34 PM, Dumitrescu, Cristian <
cristian.dumitrescu@intel.com> wrote:

> Hi Nidhia,
>
> >Hi Cristian,
> >
> >Thanks for your help.
> >
> >If that is the case, is there any way to use the incoming port as a key
> for table lookup? I need to use incoming port along with some other fields
> of each packet as the key for my application.
>
> Yes, you can. There is an input port field in the rte_mbuf structure that
> you can use.
>
> The hash tables from librte_table/rte_table_hash* work with lookup key
> placed at any location from the start of the mbuf (see the key offset
> parameter), and for some tables there is a key mask parameter as well.
> Assuming a flat buffer that has both the mbuf and the packet in the same
> buffer (see the buffer anatomy in rte_mbuf.h), the key offset parameter can
> basically cover any location from the buffer, including meta-data (fields
> from mbuf or the buffer headroom, such as the input port), as well as
> packet fields (from the header/payload, such as the DiffServ 5-tuple).
>
> You can do any of the two things below:
> 1. Use the key offset and key mask parameter of the hash table to select
> the relevant metadata/packet header fields;
> 2. Use the DMA action of the pass-through table to copy & pack the
> relevant metadata/packet header fields in some unused headroom space, and
> then point the key offset to this buffer location.
>
> >
> >Regards,
> >Nidhia Varghese
>
> Regards,
> Cristian
>



-- 

Regards,
Nidhia Varghese