[dpdk-dev] [PATCH v3 1/5] ethdev: update modify field flow action

[Viacheslav Ovsiienko <viacheslavo@nvidia.com>]

The generic modify field flow action introduced in [1] has
some issues related to the immediate source operand:

  - immediate source can be presented either as an unsigned
    64-bit integer or pointer to data pattern in memory.
    There was no explicit pointer field defined in the union.

  - the byte ordering for 64-bit integer was not specified.
    Many fields have shorter lengths and byte ordering
    is crucial.

  - how the bit offset is applied to the immediate source
    field was not defined and documented.

  - 64-bit integer size is not enough to provide IPv6
    addresses.

In order to cover the issues and exclude any ambiguities
the following is done:

  - introduce the explicit pointer field
    in rte_flow_action_modify_data structure

  - replace the 64-bit unsigned integer with 16-byte array

  - update the modify field flow action documentation

Appropriate deprecation notice has been removed.

[1] commit 73b68f4c54a0 ("ethdev: introduce generic modify flow action")

Fixes: 2ba49b5f3721 ("doc: announce change to ethdev modify action data")

Signed-off-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>
Acked-by: Ori Kam <orika@nvidia.com>
---
 doc/guides/prog_guide/rte_flow.rst     | 24 +++++++++++++++++++++++-
 doc/guides/rel_notes/deprecation.rst   |  4 ----
 doc/guides/rel_notes/release_21_11.rst |  7 +++++++
 lib/ethdev/rte_flow.h                  | 16 ++++++++++++----
 4 files changed, 42 insertions(+), 9 deletions(-)

diff --git a/doc/guides/prog_guide/rte_flow.rst b/doc/guides/prog_guide/rte_flow.rst
index 2b42d5ec8c..b08087511f 100644
--- a/doc/guides/prog_guide/rte_flow.rst
+++ b/doc/guides/prog_guide/rte_flow.rst
@@ -2835,6 +2835,22 @@ a packet to any other part of it.
 ``value`` sets an immediate value to be used as a source or points to a
 location of the value in memory. It is used instead of ``level`` and ``offset``
 for ``RTE_FLOW_FIELD_VALUE`` and ``RTE_FLOW_FIELD_POINTER`` respectively.
+The data in memory should be presented exactly in the same byte order and
+length as in the relevant flow item, i.e. data for field with type
+``RTE_FLOW_FIELD_MAC_DST`` should follow the conventions of ``dst`` field
+in ``rte_flow_item_eth`` structure, with type ``RTE_FLOW_FIELD_IPV6_SRC`` -
+``rte_flow_item_ipv6`` conventions, and so on. If the field size is larger than
+16 bytes the pattern can be provided as pointer only.
+
+The bitfield extracted from the memory being applied as second operation
+parameter is defined by action width and by the destination field offset.
+Application should provide the data in immediate value memory (either as
+buffer or by pointer) exactly as item field without any applied explicit offset,
+and destination packet field (with specified width and bit offset) will be
+replaced by immediate source bits from the same bit offset. For example,
+to replace the third byte of MAC address with value 0x85, application should
+specify destination width as 8, destination offset as 16, and provide immediate
+value as sequence of bytes {xxx, xxx, 0x85, xxx, xxx, xxx}.
 
 .. _table_rte_flow_action_modify_field:
 
@@ -2865,7 +2881,13 @@ for ``RTE_FLOW_FIELD_VALUE`` and ``RTE_FLOW_FIELD_POINTER`` respectively.
    +---------------+----------------------------------------------------------+
    | ``offset``    | number of bits to skip at the beginning                  |
    +---------------+----------------------------------------------------------+
-   | ``value``     | immediate value or a pointer to this value               |
+   | ``value``     | immediate value buffer (source field only, not           |
+   |               | applicable to destination) for RTE_FLOW_FIELD_VALUE      |
+   |               | field type                                               |
+   +---------------+----------------------------------------------------------+
+   | ``pvalue``    | pointer to immediate value data (source field only, not  |
+   |               | applicable to destination) for RTE_FLOW_FIELD_POINTER    |
+   |               | field type                                               |
    +---------------+----------------------------------------------------------+
 
 Action: ``CONNTRACK``
diff --git a/doc/guides/rel_notes/deprecation.rst b/doc/guides/rel_notes/deprecation.rst
index a2fe766d4b..dee14077a5 100644
--- a/doc/guides/rel_notes/deprecation.rst
+++ b/doc/guides/rel_notes/deprecation.rst
@@ -120,10 +120,6 @@ Deprecation Notices
 * ethdev: Announce moving from dedicated modify function for each field,
   to using the general ``rte_flow_modify_field`` action.
 
-* ethdev: The struct ``rte_flow_action_modify_data`` will be modified
-  to support modifying fields larger than 64 bits.
-  In addition, documentation will be updated to clarify byte order.
-
 * ethdev: Attribute ``shared`` of the ``struct rte_flow_action_count``
   is deprecated and will be removed in DPDK 21.11. Shared counters should
   be managed using shared actions API (``rte_flow_shared_action_create`` etc).
diff --git a/doc/guides/rel_notes/release_21_11.rst b/doc/guides/rel_notes/release_21_11.rst
index dfc2cbdeed..578c1206e7 100644
--- a/doc/guides/rel_notes/release_21_11.rst
+++ b/doc/guides/rel_notes/release_21_11.rst
@@ -187,6 +187,13 @@ API Changes
   the crypto/security operation. This field will be used to communicate
   events such as soft expiry with IPsec in lookaside mode.
 
+* ethdev: ``rte_flow_action_modify_data`` structure updated, immediate data
+  array is extended, data pointer field is explicitly added to union, the
+  action behavior is defined in more strict fashion and documentation updated.
+  The immediate value behavior has been changed, the entire immediate field
+  should be provided, and offset for immediate source bitfield is assigned
+  from destination one.
+
 
 ABI Changes
 -----------
diff --git a/lib/ethdev/rte_flow.h b/lib/ethdev/rte_flow.h
index 7b1ed7f110..f14f77772b 100644
--- a/lib/ethdev/rte_flow.h
+++ b/lib/ethdev/rte_flow.h
@@ -3217,10 +3217,18 @@ struct rte_flow_action_modify_data {
 			uint32_t offset;
 		};
 		/**
-		 * Immediate value for RTE_FLOW_FIELD_VALUE or
-		 * memory address for RTE_FLOW_FIELD_POINTER.
+		 * Immediate value for RTE_FLOW_FIELD_VALUE, presented in the
+		 * same byte order and length as in relevant rte_flow_item_xxx.
+		 * The immediate source bitfield offset is inherited from
+		 * the destination's one.
 		 */
-		uint64_t value;
+		uint8_t value[16];
+		/**
+		 * Memory address for RTE_FLOW_FIELD_POINTER, memory layout
+		 * should be the same as for relevant field in the
+		 * rte_flow_item_xxx structure.
+		 */
+		void *pvalue;
 	};
 };
 
@@ -3240,7 +3248,7 @@ enum rte_flow_modify_op {
  * RTE_FLOW_ACTION_TYPE_MODIFY_FIELD
  *
  * Modify a destination header field according to the specified
- * operation. Another packet field can be used as a source as well
+ * operation. Another field of the packet can be used as a source as well
  * as tag, mark, metadata, immediate value or a pointer to it.
  */
 struct rte_flow_action_modify_field {
-- 
2.18.1