[dpdk-dev] [RFC] ethdev: add action to swap source and destination MAC to flow API

[Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>]

From: Shagun Agrawal <shaguna@chelsio.com>

This action is useful for offloading loopback mode, where the hardware
will swap source and destination MAC address before looping back the
packet. This action can be used in conjunction with other rewrite
actions to achieve MAC layer transparent NAT where the MAC addresses
are swapped before either the source or destination MAC address
is rewritten and NAT is performed.

Signed-off-by: Shagun Agrawal <shaguna@chelsio.com>
Signed-off-by: Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>
---
 app/test-pmd/cmdline_flow.c                 |  9 +++++++++
 app/test-pmd/config.c                       |  1 +
 doc/guides/prog_guide/rte_flow.rst          | 15 +++++++++++++++
 doc/guides/testpmd_app_ug/testpmd_funcs.rst |  2 ++
 lib/librte_ethdev/rte_flow.c                |  1 +
 lib/librte_ethdev/rte_flow.h                |  7 +++++++
 6 files changed, 35 insertions(+)

diff --git a/app/test-pmd/cmdline_flow.c b/app/test-pmd/cmdline_flow.c
index f9260600e..4b83b55c4 100644
--- a/app/test-pmd/cmdline_flow.c
+++ b/app/test-pmd/cmdline_flow.c
@@ -243,6 +243,7 @@ enum index {
 	ACTION_VXLAN_DECAP,
 	ACTION_NVGRE_ENCAP,
 	ACTION_NVGRE_DECAP,
+	ACTION_MAC_SWAP,
 };
 
 /** Maximum size for pattern in struct rte_flow_item_raw. */
@@ -816,6 +817,7 @@ static const enum index next_action[] = {
 	ACTION_VXLAN_DECAP,
 	ACTION_NVGRE_ENCAP,
 	ACTION_NVGRE_DECAP,
+	ACTION_MAC_SWAP,
 	ZERO,
 };
 
@@ -2470,6 +2472,13 @@ static const struct token token_list[] = {
 		.next = NEXT(NEXT_ENTRY(ACTION_NEXT)),
 		.call = parse_vc,
 	},
+	[ACTION_MAC_SWAP] = {
+		.name = "mac_swap",
+		.help = "swap source and destination mac address",
+		.priv = PRIV_ACTION(MAC_SWAP, 0),
+		.next = NEXT(NEXT_ENTRY(ACTION_NEXT)),
+		.call = parse_vc,
+	},
 };
 
 /** Remove and return last entry from argument stack. */
diff --git a/app/test-pmd/config.c b/app/test-pmd/config.c
index 14ccd6864..b7393967a 100644
--- a/app/test-pmd/config.c
+++ b/app/test-pmd/config.c
@@ -1153,6 +1153,7 @@ static const struct {
 		       sizeof(struct rte_flow_action_of_pop_mpls)),
 	MK_FLOW_ACTION(OF_PUSH_MPLS,
 		       sizeof(struct rte_flow_action_of_push_mpls)),
+	MK_FLOW_ACTION(MAC_SWAP, 0),
 };
 
 /** Compute storage space needed by action configuration and copy it. */
diff --git a/doc/guides/prog_guide/rte_flow.rst b/doc/guides/prog_guide/rte_flow.rst
index b305a72a5..530dbc504 100644
--- a/doc/guides/prog_guide/rte_flow.rst
+++ b/doc/guides/prog_guide/rte_flow.rst
@@ -2076,6 +2076,21 @@ RTE_FLOW_ERROR_TYPE_ACTION error should be returned.
 
 This action modifies the payload of matched flows.
 
+Action: ``MAC_SWAP``
+^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Swap source and destination mac address.
+
+.. _table_rte_flow_action_mac_swap:
+
+.. table:: MAC_SWAP
+
+   +---------------+
+   | Field         |
+   +===============+
+   | no properties |
+   +---------------+
+
 Negative types
 ~~~~~~~~~~~~~~
 
diff --git a/doc/guides/testpmd_app_ug/testpmd_funcs.rst b/doc/guides/testpmd_app_ug/testpmd_funcs.rst
index dde205a2b..4f0da4fb6 100644
--- a/doc/guides/testpmd_app_ug/testpmd_funcs.rst
+++ b/doc/guides/testpmd_app_ug/testpmd_funcs.rst
@@ -3697,6 +3697,8 @@ This section lists supported actions and their attributes, if any.
 - ``nvgre_decap``: Performs a decapsulation action by stripping all headers of
   the NVGRE tunnel network overlay from the matched flow.
 
+- ``mac_swap``: Swap source and destination mac address.
+
 Destroying flow rules
 ~~~~~~~~~~~~~~~~~~~~~
 
diff --git a/lib/librte_ethdev/rte_flow.c b/lib/librte_ethdev/rte_flow.c
index cff4b5209..04b0b40ea 100644
--- a/lib/librte_ethdev/rte_flow.c
+++ b/lib/librte_ethdev/rte_flow.c
@@ -109,6 +109,7 @@ static const struct rte_flow_desc_data rte_flow_desc_action[] = {
 		       sizeof(struct rte_flow_action_of_pop_mpls)),
 	MK_FLOW_ACTION(OF_PUSH_MPLS,
 		       sizeof(struct rte_flow_action_of_push_mpls)),
+	MK_FLOW_ACTION(MAC_SWAP, 0),
 };
 
 static int
diff --git a/lib/librte_ethdev/rte_flow.h b/lib/librte_ethdev/rte_flow.h
index f8ba71cdb..e1fa17b7e 100644
--- a/lib/librte_ethdev/rte_flow.h
+++ b/lib/librte_ethdev/rte_flow.h
@@ -1505,6 +1505,13 @@ enum rte_flow_action_type {
 	 * error.
 	 */
 	RTE_FLOW_ACTION_TYPE_NVGRE_DECAP,
+
+	/**
+	 * swap the source and destination mac address in ethernet header
+	 *
+	 * No associated configuration structure.
+	 */
+	RTE_FLOW_ACTION_TYPE_MAC_SWAP,
 };
 
 /**
-- 
2.14.1