[RFC] ethdev: sharing indirect actions between ports

[Viacheslav Ovsiienko <viacheslavo@nvidia.com>]

The RTE Flow API implements the concept of shared objects,
known as indirect actions (RTE_FLOW_ACTION_TYPE_INDIRECT).
An application can create the indirect action of desired
type and configuration with rte_flow_action_handle_create
call and then specify the obtained action handle in multiple
flows.

The initial concept supposes the action handle has strict
attachment to the port it was created on and to be used
exclusively in the flows being installed on the port.

Nowadays the multipath network topologies are quite common,
packets belonging to the same connection might arrive and
be sent over multiple ports, and there is the raising demand
to handle these "spread" connections. To fulfil this demand
it is proposed to extend indirect action sharing across the
multiple ports. This kind of sharing would be extremely useful
for the meters and counters, allowing to manage the single
connection over the multiple ports.

This cross-port object sharing is hard to implement in
generic way merely with software on the upper layers, but
can be provided by the driver over the single hardware
instance, where  multiple ports reside on the same physical
NIC and share the same hardware context.

To allow this action sharing application should specify
the "host port" during flow configuring to claim the intention
to share the indirect actions. All indirect actions reside within
"host port" context and can be shared in flows being installed
on the host port and on all the ports referencing this one.

If sharing between host and port being configured is not supported
the configuration should be rejected with error. There might be
multiple independent (mutual exclusive) sharing domains with
dedicated host and referencing ports.

To manage the shared indirect action any port from sharing domain
can be specified. To share or not the created action is up to
application, no API change is needed.

Signed-off-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>
---
 lib/ethdev/rte_flow.c |  6 ++++++
 lib/ethdev/rte_flow.h | 11 +++++++++++
 2 files changed, 17 insertions(+)

diff --git a/lib/ethdev/rte_flow.c b/lib/ethdev/rte_flow.c
index 7d0c24366c..692d37925a 100644
--- a/lib/ethdev/rte_flow.c
+++ b/lib/ethdev/rte_flow.c
@@ -1476,6 +1476,12 @@ rte_flow_configure(uint16_t port_id,
 		RTE_FLOW_LOG(ERR, "Port %"PRIu16" queue info is NULL.\n", port_id);
 		return -EINVAL;
 	}
+	if ((port_attr->flags & RTE_FLOW_PORT_FLAG_SHARE_INDIRECT) &&
+	     !rte_eth_dev_is_valid_port(port_attr->host_port_id)) {
+		return rte_flow_error_set(error, ENODEV,
+					  RTE_FLOW_ERROR_TYPE_UNSPECIFIED,
+					  NULL, rte_strerror(ENODEV));
+	}
 	if (likely(!!ops->configure)) {
 		ret = ops->configure(dev, port_attr, nb_queue, queue_attr, error);
 		if (ret == 0)
diff --git a/lib/ethdev/rte_flow.h b/lib/ethdev/rte_flow.h
index b60987db4b..c784f4ec30 100644
--- a/lib/ethdev/rte_flow.h
+++ b/lib/ethdev/rte_flow.h
@@ -4903,6 +4903,13 @@ rte_flow_info_get(uint16_t port_id,
 		  struct rte_flow_queue_info *queue_info,
 		  struct rte_flow_error *error);
 
+/**
+ * Indicate all steering objects should be created on contexts
+ * of the host port, providing indirect object sharing beetween
+ * ports.
+ */
+#define RTE_FLOW_PORT_FLAG_SHARE_INDIRECT RTE_BIT32(0)
+
 /**
  * @warning
  * @b EXPERIMENTAL: this API may change without prior notice.
@@ -4932,6 +4939,10 @@ struct rte_flow_port_attr {
 	 * @see RTE_FLOW_ACTION_TYPE_CONNTRACK
 	 */
 	uint32_t nb_conn_tracks;
+	/**
+	 * Port to base shared objects on.
+	 */
+	uint16_t host_port_id;
 	/**
 	 * Port flags (RTE_FLOW_PORT_FLAG_*).
 	 */
-- 
2.18.1