[dpdk-dev] [PATCH] net/mlx5: fix validation of push VLAN without full mask

[Xiaoyu Min]

Due the limitation of HW, when PMD create push VLAN action it needs to
know what exactly the value of VID/PCP.

PMD try to figure out them via:
  - of_set_vlan_vid/pcp actions
  - VLAN item in pattern
If none of above is provided, default value - zero is used.

However user will write rule like [1] which match on a range of VID and
without of_set_vlan_vid action and expect the VID will inherit from
original packet. This is not supported by HW currently. PMD will set VID
to default value - zero because it cannot figure out the exact value of VID
from VLAN item.

This is sort of misleading for some users.

In order to avoid this, PMD will spit out error for rule like [1] to
force user to provide explicit VID/PCP for new pushed VLAN headers.

Fixes: 9aee7a8418d4 ("net/mlx5: support push flow action on VLAN header")
Cc: stable at dpdk.org

[1]: testpmd> flow create 2 ingress transfer group 0 priority 3 pattern
               eth / vlan vid spec 2859 vid prefix 4 / ipv4 / end
	       actcions  of_push_vlan ethertype 0x88A8 /
	       of_set_vlan_pcp vlan_pcp 6 / port_id id 0 / end

Signed-off-by: Xiaoyu Min <jackmin at mellanox.com>
Reviewed-by: Dekel Peled <dekelp at mellanox.com>
---
 drivers/net/mlx5/mlx5_flow_dv.c | 34 +++++++++++++++++++++++++++++++--
 1 file changed, 32 insertions(+), 2 deletions(-)

diff --git a/drivers/net/mlx5/mlx5_flow_dv.c b/drivers/net/mlx5/mlx5_flow_dv.c
index 6aa6e8383d..eb7d499f7e 100644
--- a/drivers/net/mlx5/mlx5_flow_dv.c
+++ b/drivers/net/mlx5/mlx5_flow_dv.c
@@ -1829,7 +1829,7 @@ flow_dev_get_vlan_info_from_items(const struct rte_flow_item *items,
 static int
 flow_dv_validate_action_push_vlan(struct rte_eth_dev *dev,
 				  uint64_t action_flags,
-				  uint64_t item_flags __rte_unused,
+				  const struct rte_flow_item_vlan *vlan_m,
 				  const struct rte_flow_action *action,
 				  const struct rte_flow_attr *attr,
 				  struct rte_flow_error *error)
@@ -1863,6 +1863,32 @@ flow_dv_validate_action_push_vlan(struct rte_eth_dev *dev,
 					  RTE_FLOW_ERROR_TYPE_UNSPECIFIED, NULL,
 					  "push vlan action for VF representor "
 					  "not supported on NIC table");
+	if (vlan_m &&
+	    (vlan_m->tci & MLX5DV_FLOW_VLAN_PCP_MASK_BE) &&
+	    (vlan_m->tci & MLX5DV_FLOW_VLAN_PCP_MASK_BE) !=
+		MLX5DV_FLOW_VLAN_PCP_MASK_BE &&
+	    !(action_flags & MLX5_FLOW_ACTION_OF_SET_VLAN_PCP) &&
+	    !(mlx5_flow_find_action
+		(action + 1, RTE_FLOW_ACTION_TYPE_OF_SET_VLAN_PCP)))
+		return rte_flow_error_set(error, EINVAL,
+					  RTE_FLOW_ERROR_TYPE_ACTION, action,
+					  "not full match mask on VLAN PCP and "
+					  "there is no of_set_vlan_pcp action, "
+					  "push VLAN action cannot figure out "
+					  "PCP value");
+	if (vlan_m &&
+	    (vlan_m->tci & MLX5DV_FLOW_VLAN_VID_MASK_BE) &&
+	    (vlan_m->tci & MLX5DV_FLOW_VLAN_VID_MASK_BE) !=
+		MLX5DV_FLOW_VLAN_VID_MASK_BE &&
+	    !(action_flags & MLX5_FLOW_ACTION_OF_SET_VLAN_VID) &&
+	    !(mlx5_flow_find_action
+		(action + 1, RTE_FLOW_ACTION_TYPE_OF_SET_VLAN_VID)))
+		return rte_flow_error_set(error, EINVAL,
+					  RTE_FLOW_ERROR_TYPE_ACTION, action,
+					  "not full match mask on VLAN VID and "
+					  "there is no of_set_vlan_vid action, "
+					  "push VLAN action cannot figure out "
+					  "VID value");
 	(void)attr;
 	return 0;
 }
@@ -4580,6 +4606,7 @@ flow_dv_validate(struct rte_eth_dev *dev, const struct rte_flow_attr *attr,
 	struct mlx5_priv *priv = dev->data->dev_private;
 	struct mlx5_dev_config *dev_conf = &priv->config;
 	uint16_t queue_index = 0xFFFF;
+	const struct rte_flow_item_vlan *vlan_m = NULL;
 
 	if (items == NULL)
 		return -1;
@@ -4637,6 +4664,9 @@ flow_dv_validate(struct rte_eth_dev *dev, const struct rte_flow_attr *attr,
 			} else {
 				ether_type = 0;
 			}
+			/* Store outer VLAN mask for of_push_vlan action. */
+			if (!tunnel)
+				vlan_m = items->mask;
 			break;
 		case RTE_FLOW_ITEM_TYPE_IPV4:
 			mlx5_flow_tunnel_ip_check(items, next_protocol,
@@ -4952,7 +4982,7 @@ flow_dv_validate(struct rte_eth_dev *dev, const struct rte_flow_attr *attr,
 		case RTE_FLOW_ACTION_TYPE_OF_PUSH_VLAN:
 			ret = flow_dv_validate_action_push_vlan(dev,
 								action_flags,
-								item_flags,
+								vlan_m,
 								actions, attr,
 								error);
 			if (ret < 0)
-- 
2.26.0