Re: [dpdk-dev] [PATCH] ethdev: introduce generic copy rte flow action

[Asaf Penso <asafp@nvidia.com>]

Correct, Ori. We'll soon send the testpmd part and pmd draft.

Regards,
Asaf Penso

>-----Original Message-----
>From: dev <dev-bounces@dpdk.org> On Behalf Of Ori Kam
>Sent: Sunday, January 10, 2021 10:01 AM
>To: Alexander Kozyrev <akozyrev@nvidia.com>; dev@dpdk.org
>Cc: Slava Ovsiienko <viacheslavo@nvidia.com>; NBU-Contact-Thomas
>Monjalon <thomas@monjalon.net>; ferruh.yigit@intel.com;
>andrew.rybchenko@oktetlabs.ru
>Subject: Re: [dpdk-dev] [PATCH] ethdev: introduce generic copy rte flow
>action
>
>Hi Alexander,
>
>I guess that the test-pmd part will be available later right?
>
>> -----Original Message-----
>> From: Alexander Kozyrev <akozyrev@nvidia.com>
>> Sent: Friday, January 8, 2021 8:33 AM
>> Subject: [PATCH] ethdev: introduce generic copy rte flow action
>>
>> 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.
>>
>
>Since the question why you are using enum and not just offset from the start
>of the packet, was discussed and raised by number of people it will be best if
>it will appear in the commit log, at least the advantages to this
>implementation.
>
>> RFC:
>>
>https://nam11.safelinks.protection.outlook.com/?url=http%3A%2F%2Fpatch
>> es.d
>pdk.org%2Fpatch%2F85384%2F&amp;data=04%7C01%7Corika%40nvidia.com
>%
>> 7Cd04c2e49c3a840994da408d8b39f3304%7C43083d15727340c1b7db39efd9cc
>>
>c17a%7C0%7C0%7C637456843629116269%7CUnknown%7CTWFpbGZsb3d8eyJ
>>
>WIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7
>C
>>
>1000&amp;sdata=85096rASBtzbjU42pV6sPkl3nVt5HlR6%2BL9nxI3qgFA%3D&a
>> mp;reserved=0
>>
>> Signed-off-by: Alexander Kozyrev <akozyrev@nvidia.com>
>> ---
>>  doc/guides/prog_guide/rte_flow.rst | 35 ++++++++++++++++++
>>  lib/librte_ethdev/rte_flow.c       |  1 +
>>  lib/librte_ethdev/rte_flow.h       | 59
>++++++++++++++++++++++++++++++
>>  3 files changed, 95 insertions(+)
>>
>> diff --git a/doc/guides/prog_guide/rte_flow.rst
>> b/doc/guides/prog_guide/rte_flow.rst
>> index 86b3444803..b737ff9dad 100644
>> --- a/doc/guides/prog_guide/rte_flow.rst
>> +++ b/doc/guides/prog_guide/rte_flow.rst
>> @@ -2766,6 +2766,41 @@ The behaviour of the shared action defined by
>> ``action`` argument of type
>>     | no properties |
>>     +---------------+
>>
>> +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``.
>> +
>
>For tag I think you should also use the index right?
>
>> +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.
>
>Please specify  what means index 0 /1 ... 0 is outer most? Inner most?
>You can look at the RSS level for reference.
>I think it will be best to use the same values.
>
>What happens if we want to copy between different sizes?
>for example copy IPV6 src to number of tags? I assume we will be using offset
>and split the copy command to number of actions right?
>
>> +
>> +.. _table_rte_flow_action_copy_item:
>> +
>> +.. table:: COPY_ITEM
>> +
>> +   +-----------------------------------------+
>> +   | Field         | Value                   |
>> +   +===============+=========================+
>> +   | ``dst``       | destination item        |
>> +   | ``src``       | source item             |
>> +   | ``width``     | number of bits to copy  |
>> +   +---------------+-------------------------+
>> +
>> +.. _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   |
>> +   +---------------+------------------------------------------+
>> +
>>  Negative types
>>  ~~~~~~~~~~~~~~
>>
>> diff --git a/lib/librte_ethdev/rte_flow.c
>> b/lib/librte_ethdev/rte_flow.c index a06f64c271..fdbabefc47 100644
>> --- a/lib/librte_ethdev/rte_flow.c
>> +++ b/lib/librte_ethdev/rte_flow.c
>> @@ -176,6 +176,7 @@ static const struct rte_flow_desc_data
>> rte_flow_desc_action[] = {
>>  	MK_FLOW_ACTION(SET_IPV6_DSCP, sizeof(struct
>> rte_flow_action_set_dscp)),
>>  	MK_FLOW_ACTION(AGE, sizeof(struct rte_flow_action_age)),
>>  	MK_FLOW_ACTION(SAMPLE, sizeof(struct rte_flow_action_sample)),
>> +	MK_FLOW_ACTION(COPY_ITEM, sizeof(struct
>> rte_flow_action_copy_item)),
>>  	/**
>>  	 * Shared action represented as handle of type
>>  	 * (struct rte_flow_shared action *) stored in conf field (see diff
>> --git a/lib/librte_ethdev/rte_flow.h b/lib/librte_ethdev/rte_flow.h
>> index 0977a78270..0540c861fb 100644
>> --- a/lib/librte_ethdev/rte_flow.h
>> +++ b/lib/librte_ethdev/rte_flow.h
>> @@ -2198,6 +2198,16 @@ enum rte_flow_action_type {
>>  	 * struct rte_flow_shared_action).
>>  	 */
>>  	RTE_FLOW_ACTION_TYPE_SHARED,
>> +
>> +	/**
>> +	 * Copy a packet header field, tag, mark or metadata.
>> +	 *
>> +	 * Allow saving an arbitrary header field by copying its value
>> +	 * to a tag/mark/metadata or copy it into another header field.
>> +	 *
>> +	 * See struct rte_flow_action_copy_item.
>> +	 */
>> +	RTE_FLOW_ACTION_TYPE_COPY_ITEM,
>>  };
>>
>>  /**
>> @@ -2791,6 +2801,55 @@ struct rte_flow_action_set_dscp {
>>   */
>>  struct rte_flow_shared_action;
>>
>> +enum rte_flow_item_id {
>> +	RTE_FLOW_ITEM_NONE = 0,
>> +	RTE_FLOW_ITEM_MAC_DST,
>> +	RTE_FLOW_ITEM_MAC_SRC,
>> +	RTE_FLOW_ITEM_VLAN_TYPE,
>> +	RTE_FLOW_ITEM_VLAN_ID,
>> +	RTE_FLOW_ITEM_MAC_TYPE,
>> +	RTE_FLOW_ITEM_IPV4_DSCP,
>> +	RTE_FLOW_ITEM_IPV4_TTL,
>> +	RTE_FLOW_ITEM_IPV4_SRC,
>> +	RTE_FLOW_ITEM_IPV4_DST,
>> +	RTE_FLOW_ITEM_IPV6_HOPLIMIT,
>> +	RTE_FLOW_ITEM_IPV6_SRC,
>> +	RTE_FLOW_ITEM_IPV6_DST,
>> +	RTE_FLOW_ITEM_TCP_PORT_SRC,
>> +	RTE_FLOW_ITEM_TCP_PORT_DST,
>> +	RTE_FLOW_ITEM_TCP_SEQ_NUM,
>> +	RTE_FLOW_ITEM_TCP_ACK_NUM,
>> +	RTE_FLOW_ITEM_TCP_FLAGS,
>> +	RTE_FLOW_ITEM_UDP_PORT_SRC,
>> +	RTE_FLOW_ITEM_UDP_PORT_DST,
>> +	RTE_FLOW_ITEM_VXLAN_VNI,
>> +	RTE_FLOW_ITEM_GENEVE_VNI,
>> +	RTE_FLOW_ITEM_GTP_TEID,
>> +	RTE_FLOW_ITEM_TAG,
>> +	RTE_FLOW_ITEM_MARK,
>> +	RTE_FLOW_ITEM_META,
>> +};
>
>I don't think this name is good since it not rte_flow_item this is just internal
>enumeration for this action.
>
>> +
>> +struct rte_flow_action_copy_data {
>> +	enum rte_flow_item_id item;
>> +	uint32_t index;
>> +	uint32_t offset;
>
>Why use 32 bits? Since this copy only one register with max len of 32 bit.
>The max offset can 31? Same for the index.
>
>> +};
>> +
>> +/**
>> + * RTE_FLOW_ACTION_TYPE_COPY_ITEM
>> + *
>> + * Copies a specified number of bits from a source header field
>> + * to a destination header field. Tag, mark or metadata can also
>> + * be used as a source/destination to allow saving/overwriting
>> + * an arbituary header field with a user-specified value.
>> + */
>> +struct rte_flow_action_copy_item {
>> +	struct rte_flow_action_copy_data dst;
>> +	struct rte_flow_action_copy_data src;
>> +	uint32_t width;
>
>Why use 32 bit register?
>
>> +};
>> +
>>  /* Mbuf dynamic field offset for metadata. */  extern int32_t
>> rte_flow_dynf_metadata_offs;
>>
>> --
>> 2.24.1
>
>Best,
>Ori