[dpdk-dev] [PATCH] ethdev: introduce generic copy rte flow action
Jerin Jacob
jerinjacobk at gmail.com
Thu Jan 14 14:59:41 CET 2021
On Fri, Jan 8, 2021 at 12:02 PM Alexander Kozyrev <akozyrev at nvidia.com> wrote:
>
> Implement a generic copy flow API to allow copying of an arbitrary
> header field (as well as mark, metadata or tag) to another item.
>
> This generic copy mechanism removes the necessity to implement a
> separate RTE Flow action every time we need to modify a new packet
> field in the future. A user-provided value can be used from a
> specified tag/metadata or directly copied from other packet field.
>
> The number of bits to copy as well as the offset to start from can
> be specified to allow a partial copy or copy into an arbitrary
> place in a packet for greater flexibility.
>
> RFC: http://patches.dpdk.org/patch/85384/
>
> Signed-off-by: Alexander Kozyrev <akozyrev at nvidia.com>
> ---
>
> +Action: ``COPY_ITEM``
> +^^^^^^^^^^^^^^^^^^^^^
> +
> +Copy ``width`` bits from ``src`` item to ``dst`` item.
> +
> +An arbitrary header field (as well as mark, metadata or tag values)
> +can be used as both source and destination items as set by ``item``.
> +
> +Inner packet header fields can be accessed using the ``index`` and
> +it is possible to start the copy from the ``offset`` bits in an item.
> +
> +.. _table_rte_flow_action_copy_item:
> +
> +.. table:: COPY_ITEM
> +
> + +-----------------------------------------+
> + | Field | Value |
> + +===============+=========================+
> + | ``dst`` | destination item |
> + | ``src`` | source item |
> + | ``width`` | number of bits to copy |
Overall it is a good improvement.
I think, if we add transform "op" here then it can be more generic. In
other words, A generic packet transform and copy operation is just one
of the operations.
ie.. making it as rte_flow_action_xform_item and introduce COPY, ADD,
SUB, etc transform along with existing rte_flow_action_copy_item
fields.
It may useful for expressing P4 packet transforms to rte_flow.
The current generation of Marvell HW does not have COPY transform so I
am leaving suggestions to vendors with this HW capablity.
> + +---------------+-------------------------+
> +
> +.. _table_rte_flow_action_copy_data:
> +
> +.. table:: destination/source item definition
> +
> + +----------------------------------------------------------+
> + | Field | Value |
> + +===============+==========================================+
> + | ``item`` | ID of a packet field/mark/metadata/tag |
> + | ``index`` | index of outer/inner header or tag array |
> + | ``offset`` | number of bits to skip during the copy |
> + +---------------+------------------------------------------+
> +
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