[dpdk-dev] [RFC v2] ethdev: add flow metadata

[Xueming Li]

Currently, rte_flow pattern only match packet header fields.
This patch adds additional data to match the packet.

For example, in egress direction, to do an action depending on the VM
id, the application needs to configure rte_flow rule with the new
metadata pattern:
    pattern meta data is {vm} / end action encap …
Then the PMD will send VM id as metadata associated in mbuf to NIC,
then egress flow on NIC match metadata as other regular packet headers,
the appropriate encapsulation is done according to the VM id metadata.

Metadata could be used on ingress as well to save useful info before
flow modification (not defined yet) or decapsulation action. PMD is
responsible to save metadata into mbuf field. The application must get
metadata from the mbuf.

Cc: Thomas Monjalon <thomas at monjalon.net>
Cc: Olivier Matz <olivier.matz at 6wind.com>
Cc: Shahaf Shuler <shahafs at mellanox.com>
Signed-off-by: Xueming Li <xuemingl at mellanox.com>
---
 doc/guides/prog_guide/rte_flow.rst |  7 +++++++
 lib/librte_ethdev/rte_flow.c       |  1 +
 lib/librte_ethdev/rte_flow.h       | 28 ++++++++++++++++++++++++++++
 3 files changed, 36 insertions(+)

diff --git a/doc/guides/prog_guide/rte_flow.rst b/doc/guides/prog_guide/rte_flow.rst
index b305a72a5..7989e5856 100644
--- a/doc/guides/prog_guide/rte_flow.rst
+++ b/doc/guides/prog_guide/rte_flow.rst
@@ -1191,6 +1191,13 @@ Normally preceded by any of:
 - `Item: ICMP6_ND_NS`_
 - `Item: ICMP6_ND_OPT`_
 
+Item: ``META``
+^^^^^^^^^^^^^^
+
+Matches a metadata variable.
+
+- ``data``: 64 bit value.
+
 Actions
 ~~~~~~~
 
diff --git a/lib/librte_ethdev/rte_flow.c b/lib/librte_ethdev/rte_flow.c
index b2afba089..54a07dd4a 100644
--- a/lib/librte_ethdev/rte_flow.c
+++ b/lib/librte_ethdev/rte_flow.c
@@ -66,6 +66,7 @@ static const struct rte_flow_desc_data rte_flow_desc_item[] = {
 		     sizeof(struct rte_flow_item_icmp6_nd_opt_sla_eth)),
 	MK_FLOW_ITEM(ICMP6_ND_OPT_TLA_ETH,
 		     sizeof(struct rte_flow_item_icmp6_nd_opt_tla_eth)),
+	MK_FLOW_ITEM(META, sizeof(struct rte_flow_item_meta)),
 };
 
 /** Generate flow_action[] entry. */
diff --git a/lib/librte_ethdev/rte_flow.h b/lib/librte_ethdev/rte_flow.h
index f8ba71cdb..61b3dbe7b 100644
--- a/lib/librte_ethdev/rte_flow.h
+++ b/lib/librte_ethdev/rte_flow.h
@@ -413,6 +413,18 @@ enum rte_flow_item_type {
 	 * See struct rte_flow_item_mark.
 	 */
 	RTE_FLOW_ITEM_TYPE_MARK,
+
+	/**
+	 * Matches a metadata variable.
+	 *
+	 * Possible sources of metadata:
+	 * - mbuf udata64 field on egress
+	 * - egress metadata loopback to ingress
+	 * - data copied from packet header
+	 *
+	 * See struct rte_flow_item_meta.
+	 */
+	RTE_FLOW_ITEM_TYPE_META,
 };
 
 /**
@@ -849,6 +861,22 @@ static const struct rte_flow_item_gre rte_flow_item_gre_mask = {
 #endif
 
 /**
+ * RTE_FLOW_ITEM_TYPE_META.
+ *
+ * Matches a meta data header.
+ */
+struct rte_flow_item_meta {
+	uint64_t data;
+};
+
+/** Default mask for RTE_FLOW_ITEM_TYPE_META. */
+#ifndef __cplusplus
+static const struct rte_flow_item_meta rte_flow_item_meta_mask = {
+	.data = RTE_BE64(UINT64_MAX),
+};
+#endif
+
+/**
  * RTE_FLOW_ITEM_TYPE_FUZZY
  *
  * Fuzzy pattern match, expect faster than default.
-- 
2.13.3