[dpdk-dev] [RFC] ethdev: introduce sample action for rte flow

[Jiawei Wang <jiaweiw@mellanox.com>]

When using full offload, all traffic will be handled by the HW, and
directed to the requested vf or wire, the control application loses
visibility on the traffic.
So there's a need for an action that will enable the control application
some visibility.

The solution is introduced a new action that will sample the incoming
traffic and send a duplicated traffic in some predefined ratio to the
application, while the original packet will continue to the target
destination.

The packets sampled equals is '1/ratio', if the ratio value be set to 1
, means that the packets would be completely mirrored. The sample packet
can be assigned with different set of actions from the original packet.

In order to support the sample packet in rte_flow, new rte_flow action
definition RTE_FLOW_ACTION_TYPE_SAMPLE and structure rte_flow_action_sample
will be introduced.

The examples for the sample flow use case and result as below:
1. pattern eth / actions decap / sample (ratio=2, actions=mark 8, queue 2) / jump
This flow will result in all the matched ingress packets will be
decapsulated and jumped to next flow table, and the each second packet
will also be decapsulated, marked and sent to queue 2 of the control
application.

2. pattern eth / actions sample (ratio=1, actions=port 1) / port 2
The flow will result in all the matched ingress packets will be sent to
port 2, and also mirrored the packets and sent to port 2.

3. pattern eth / actions sample (ratio=1, actions=encap, port 0) / encap / port 0
The flow will result in all the matched egress packets will be encapsulated
and sent to wire, and also mirrored the packets and with the different
encapsulated data and sent to wire.

Add a new testpmd command 'set sample_actions' that supports the multiple
sample actions list configuration by using the index:
set sample_actions <index> <actions list>

The examples for the test-pmd command that according the above sample
flow case:
1. set sample_actions 0 mark id 0x8 / queue index 2 / end
   flow create...pattern eth / end actions raw_decap / sample ratio 2 index 0 / jump group 2 / end

2. set sample_actions 1 port_id id 1 / end
   flow create...pattern eth / end actions sample ratio 1 index 1 / port_id id 2 / end

3. set raw_encap 0 eth src.../ipv4.../...
   set raw_encap 1 eth src.../ipv4.../...
   set sample_actions 2 raw_encap index 0 / port_id id 0 / end
   flow create...pattern eth / end actions sample ratio 1 index 2 / raw_encap index 1 / port_id id 0 / end

Signed-off-by: Jiawei Wang <jiaweiw@mellanox.com>
---
 lib/librte_ethdev/rte_flow.c |  1 +
 lib/librte_ethdev/rte_flow.h | 29 +++++++++++++++++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/lib/librte_ethdev/rte_flow.c b/lib/librte_ethdev/rte_flow.c
index 1685be5f73..733871de63 100644
--- a/lib/librte_ethdev/rte_flow.c
+++ b/lib/librte_ethdev/rte_flow.c
@@ -173,6 +173,7 @@ static const struct rte_flow_desc_data rte_flow_desc_action[] = {
 	MK_FLOW_ACTION(SET_IPV4_DSCP, sizeof(struct rte_flow_action_set_dscp)),
 	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)),
 };
 
 int
diff --git a/lib/librte_ethdev/rte_flow.h b/lib/librte_ethdev/rte_flow.h
index b0e4199192..71dd82c64f 100644
--- a/lib/librte_ethdev/rte_flow.h
+++ b/lib/librte_ethdev/rte_flow.h
@@ -2099,6 +2099,13 @@ enum rte_flow_action_type {
 	 * see enum RTE_ETH_EVENT_FLOW_AGED
 	 */
 	RTE_FLOW_ACTION_TYPE_AGE,
+
+	/**
+	 * Redirects specific ratio of packets to vport or queue.
+	 *
+	 * See struct rte_flow_action_sample.
+	 */
+	RTE_FLOW_ACTION_TYPE_SAMPLE,
 };
 
 /**
@@ -2708,6 +2715,28 @@ struct rte_flow_action {
  */
 struct rte_flow;
 
+/**
+ * @warning
+ * @b EXPERIMENTAL: this structure may change without prior notice
+ *
+ * RTE_FLOW_ACTION_TYPE_SAMPLE
+ *
+ * Adds a sample action to a matched flow.
+ *
+ * The matching packets will be duplicated to a special queue or vport
+ * in the predefined probabiilty, All the packets continues processing
+ * on the default flow path.
+ *
+ * When the sample ratio is set to 1 then the packets will be 100% mirrored.
+ * Additional action list be supported to add for sampled or mirrored packets.
+ */
+struct rte_flow_action_sample {
+	/* packets sampled equals to '1/ratio' */
+	const uint32_t ratio;
+	/* sub-action list specific for the sampling hit cases */
+	const struct rte_flow_action *actions;
+};
+
 /**
  * Verbose error types.
  *
-- 
2.21.0