[v4,0/5] add feature arc in rte_graph

Feature arc represents an ordered list of features/protocols at a given
networking layer. It is a high level abstraction to connect various
rte_graph nodes, as feature nodes, and allow packets steering across
these nodes in a generic manner.

Features (or feature nodes) are nodes which handles partial or complete
handling of a protocol in fast path. Like ipv4-rewrite node, which adds
rewrite data to an outgoing IPv4 packet.

However in above example, outgoing interface(say "eth0") may have
outbound IPsec policy enabled, hence packets must be steered from
ipv4-rewrite node to ipsec-outbound-policy node for outbound IPsec
policy lookup. On the other hand, packets routed to another interface
(eth1) will not be sent to ipsec-outbound-policy node as IPsec feature
is disabled on eth1. Feature-arc allows rte_graph applications to manage
such constraints easily

Feature arc abstraction allows rte_graph based application to

1. Seamlessly steer packets across feature nodes based on whether
feature is enabled or disabled on an interface. Features enabled on one
interface may not be enabled on another interface with in a same feature
arc.

2. Allow enabling/disabling of features on an interface at runtime,
so that if a feature is disabled, packets associated with that interface
won't be steered to corresponding feature node.

3. Provides mechanism to hook custom/user-defined nodes to a feature
node and allow packet steering from feature node to custom node without
changing former's fast path function

4. Allow expressing features in a particular sequential order so that
packets are steered in an ordered way across nodes in fast path. For
eg: if IPsec and IPv4 features are enabled on an ingress interface,
packets must be sent to IPsec inbound policy node first and then to ipv4
lookup node.

This patch series adds feature arc library in rte_graph and also adds
"ipv4-output" feature arc handling in "ipv4-rewrite" node.

Changes in v4:
- Fixed clang build compilations
- Captured `feat_arc_proc` function in ABI change section of release notes

Changes in v3:
- rte_graph_feature_arc_t typedef from uint64_t to uintptr_t to fix
  compilation on 32-bit machine
- Updated images in .png format
- Added ABI change section in release notes
- Fixed DPDK CI failures

Changes in v2:
- Added unit tests for feature arc
- Fixed issues found in testing
- Added new public APIs rte_graph_feature_arc_feature_to_node(),
  rte_graph_feature_arc_feature_to_name(),
  rte_graph_feature_arc_num_features()
- Added programming guide for feature arc
- Added release notes for feature arc

Nitin Saxena (5):
  graph: add feature arc support
  graph: add feature arc option in graph create
  graph: add IPv4 output feature arc
  test/graph_feature_arc: add functional tests
  docs: add programming guide for feature arc

 app/test/meson.build                        |    1 +
 app/test/test_graph_feature_arc.c           | 1410 +++++++++++++++++++
 doc/guides/prog_guide/graph_lib.rst         |  288 ++++
 doc/guides/prog_guide/img/feature_arc-1.png |  Bin 0 -> 61532 bytes
 doc/guides/prog_guide/img/feature_arc-2.png |  Bin 0 -> 155806 bytes
 doc/guides/prog_guide/img/feature_arc-3.png |  Bin 0 -> 143697 bytes
 doc/guides/rel_notes/release_24_11.rst      |   17 +
 lib/graph/graph.c                           |    1 +
 lib/graph/graph_feature_arc.c               | 1236 ++++++++++++++++
 lib/graph/graph_populate.c                  |    7 +-
 lib/graph/graph_private.h                   |    3 +
 lib/graph/meson.build                       |    2 +
 lib/graph/node.c                            |    2 +
 lib/graph/rte_graph.h                       |    3 +
 lib/graph/rte_graph_feature_arc.h           |  431 ++++++
 lib/graph/rte_graph_feature_arc_worker.h    |  679 +++++++++
 lib/graph/version.map                       |   20 +
 lib/node/ip4_rewrite.c                      |  476 +++++--
 lib/node/ip4_rewrite_priv.h                 |   15 +-
 lib/node/node_private.h                     |   20 +-
 lib/node/rte_node_ip4_api.h                 |    3 +
 21 files changed, 4516 insertions(+), 98 deletions(-)
 create mode 100644 app/test/test_graph_feature_arc.c
 create mode 100644 doc/guides/prog_guide/img/feature_arc-1.png
 create mode 100644 doc/guides/prog_guide/img/feature_arc-2.png
 create mode 100644 doc/guides/prog_guide/img/feature_arc-3.png
 create mode 100644 lib/graph/graph_feature_arc.c
 create mode 100644 lib/graph/rte_graph_feature_arc.h
 create mode 100644 lib/graph/rte_graph_feature_arc_worker.h