[dpdk-dev] [PATCH v4 1/2] ethdev: introduce generic copy rte flow action

[Alexander Kozyrev <akozyrev@nvidia.com>]

Implement a generic copy flow API to allow copying of an arbitrary
header field (as well as mark, metadata or tag) to another field.

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/mark or directly copied from another packet field.

The field ID is used to specify the desired source/destination packet
field in order to simplify the API for various encapsulation models.
Specifying the packet field ID with the needed encapsulation level
is able to quickly get a packet field for any inner packet header.

Alternatively, the special ID (ITEM_START) can be used to point to the
very beginning of a packet. This ID in conjunction with the offset
parameter provides great flexibility to copy/modify any part of a packet
 as needed.

The number of bits to copy as well as the offset to start from can
be specified to allow a partial copy or dividing a big packet field
into multiple small fields (let's say copying 128 bits of IPv6 to 4 tags).

RFC: http://patches.dpdk.org/patch/85384/

Signed-off-by: Alexander Kozyrev <akozyrev@nvidia.com>
---
 doc/guides/prog_guide/rte_flow.rst     | 57 +++++++++++++++++++++++++
 doc/guides/rel_notes/release_21_02.rst |  5 +++
 lib/librte_ethdev/rte_flow.c           |  1 +
 lib/librte_ethdev/rte_flow.h           | 59 ++++++++++++++++++++++++++
 4 files changed, 122 insertions(+)

diff --git a/doc/guides/prog_guide/rte_flow.rst b/doc/guides/prog_guide/rte_flow.rst
index 86b3444803..9617b9c1ba 100644
--- a/doc/guides/prog_guide/rte_flow.rst
+++ b/doc/guides/prog_guide/rte_flow.rst
@@ -2766,6 +2766,63 @@ The behaviour of the shared action defined by ``action`` argument of type
    | no properties |
    +---------------+
 
+Action: ``COPY_FIELD``
+^^^^^^^^^^^^^^^^^^^^^^
+
+Copy ``width`` bits from ``src`` field to ``dst`` field.
+
+Any arbitrary header field (as well as mark, metadata or tag values)
+can be used as both source and destination fields as set by ``field``.
+``RTE_FLOW_FIELD_START`` is used to point to the beginning of a packet.
+The copy is ignored in case the field specified is not present in a packet.
+
+ ``width`` defines a number of bits to copy. A user is responsible for
+ supplying the appropriate length to copy. The width that exceeds the
+ hardware capabilities is rejected.
+
+ ``level`` is used to access any packet field on any encapsulation level
+ as well as any tag element in the tag array.
+
+- ``0`` means the default behaviour. Depending on the packet type, it can
+  mean outermost, innermost or anything in between.
+
+- ``1`` requests access to the outermost packet encapsulation level.
+
+- ``2`` and subsequent values requests access to the specified packet
+  encapsulation level, from outermost to innermost (lower to higher values).
+  For the tag array ``level`` translates directly into the array index.
+
+``offset`` specifies the number of bits to skip from an field's start.
+That allows performing a partial copy of the needed part or to divide a big
+packet field into multiple smaller fields. Alternatively, ``offset`` allows
+going past the specified packet field boundary to copy an field to an
+arbitrary place in a packet essentially providing a way to copy any part of
+a packet to any other part of it if supported by a underlying PMD driver.
+
+.. _table_rte_flow_action_copy_field:
+
+.. table:: COPY_FIELD
+
+   +-----------------------------------------+
+   | Field         | Value                   |
+   +===============+=========================+
+   | ``dst``       | destination field       |
+   | ``src``       | source field            |
+   | ``width``     | number of bits to copy  |
+   +---------------+-------------------------+
+
+.. _table_rte_flow_action_copy_data:
+
+.. table:: destination/source field definition
+
+   +--------------------------------------------------------------------------+
+   | Field         | Value                                                    |
+   +===============+==========================================================+
+   | ``field``     | field ID of a packet field or mark/metadata/tag          |
+   | ``level``     | encapsulation level of a packet field or tag array index |
+   | ``offset``    | number of bits to skip at the beginning during the copy  |
+   +---------------+----------------------------------------------------------+
+
 Negative types
 ~~~~~~~~~~~~~~
 
diff --git a/doc/guides/rel_notes/release_21_02.rst b/doc/guides/rel_notes/release_21_02.rst
index 706cbf8f0c..109b082931 100644
--- a/doc/guides/rel_notes/release_21_02.rst
+++ b/doc/guides/rel_notes/release_21_02.rst
@@ -55,6 +55,11 @@ New Features
      Also, make sure to start the actual text at the margin.
      =======================================================
 
+* **Added support of copy action in the flow API.**
+
+  Added copy action support to copy any arbitrary header field
+  (as well as mark, metadata or tag values) to another one:
+  ``RTE_FLOW_ACTION_TYPE_COPY_FIELD``.
 
 Removed Items
 -------------
diff --git a/lib/librte_ethdev/rte_flow.c b/lib/librte_ethdev/rte_flow.c
index a06f64c271..c3154a29e2 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_FIELD, sizeof(struct rte_flow_action_copy_field)),
 	/**
 	 * 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..e2a2807f65 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_field.
+	 */
+	RTE_FLOW_ACTION_TYPE_COPY_FIELD,
 };
 
 /**
@@ -2791,6 +2801,55 @@ struct rte_flow_action_set_dscp {
  */
 struct rte_flow_shared_action;
 
+enum rte_flow_field_id {
+	RTE_FLOW_FIELD_START = 0,
+	RTE_FLOW_FIELD_MAC_DST,
+	RTE_FLOW_FIELD_MAC_SRC,
+	RTE_FLOW_FIELD_VLAN_TYPE,
+	RTE_FLOW_FIELD_VLAN_ID,
+	RTE_FLOW_FIELD_MAC_TYPE,
+	RTE_FLOW_FIELD_IPV4_DSCP,
+	RTE_FLOW_FIELD_IPV4_TTL,
+	RTE_FLOW_FIELD_IPV4_SRC,
+	RTE_FLOW_FIELD_IPV4_DST,
+	RTE_FLOW_FIELD_IPV6_HOPLIMIT,
+	RTE_FLOW_FIELD_IPV6_SRC,
+	RTE_FLOW_FIELD_IPV6_DST,
+	RTE_FLOW_FIELD_TCP_PORT_SRC,
+	RTE_FLOW_FIELD_TCP_PORT_DST,
+	RTE_FLOW_FIELD_TCP_SEQ_NUM,
+	RTE_FLOW_FIELD_TCP_ACK_NUM,
+	RTE_FLOW_FIELD_TCP_FLAGS,
+	RTE_FLOW_FIELD_UDP_PORT_SRC,
+	RTE_FLOW_FIELD_UDP_PORT_DST,
+	RTE_FLOW_FIELD_VXLAN_VNI,
+	RTE_FLOW_FIELD_GENEVE_VNI,
+	RTE_FLOW_FIELD_GTP_TEID,
+	RTE_FLOW_FIELD_TAG,
+	RTE_FLOW_FIELD_MARK,
+	RTE_FLOW_FIELD_META,
+};
+
+struct rte_flow_action_copy_data {
+	enum rte_flow_field_id field;
+	uint32_t level;
+	uint32_t offset;
+};
+
+/**
+ * RTE_FLOW_ACTION_TYPE_COPY_FIELD
+ *
+ * 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 arbitrary header field with a user-specified value.
+ */
+struct rte_flow_action_copy_field {
+	struct rte_flow_action_copy_data dst;
+	struct rte_flow_action_copy_data src;
+	uint32_t width;
+};
+
 /* Mbuf dynamic field offset for metadata. */
 extern int32_t rte_flow_dynf_metadata_offs;
 
-- 
2.24.1