Re: [PATCH v3 0/5] add feature arc in rte_graph

[Christophe Fontaine <cfontain@redhat.com>]

> On 9 Oct 2024, at 15:29, Nitin Saxena <nsaxena@marvell.com> wrote:
> 
> 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

Hi,

As a general comment, I would have expected a modification on rte_graph_walk so the nodes would *not* need to be aware of the enabled feature arcs.
Yet, in the series, the nodes need to be aware if a feature arc is enabled or not.
Isn’t this a contradiction or did I miss something ?

Christophe

> 
> 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 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      |   13 +
> lib/graph/graph.c                           |    1 +
> lib/graph/graph_feature_arc.c               | 1223 ++++++++++++++++
> 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    |  674 +++++++++
> 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, 4494 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
> 
> -- 
> 2.43.0
>