net/mlx5e: Support VLAN modify action

Support VLAN modify action by emulating a rewrite action for the VLAN
fields. Currently, the only supported field is the vid. The prio in the
action must be set to 0 to indicate no change.
Signed-off-by: Eli Britstein <elibr@mellanox.com>
Reviewed-by: Roi Dayan <roid@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

drivers/net/ethernet/mellanox/mlx5/core/en_tc.c

@@ -2249,6 +2249,35 @@ static bool same_hw_devs(struct mlx5e_priv *priv, struct mlx5e_priv *peer_priv)
 	return (fsystem_guid == psystem_guid);
 }
 
+static int add_vlan_rewrite_action(struct mlx5e_priv *priv, int namespace,
+				   const struct flow_action_entry *act,
+				   struct mlx5e_tc_flow_parse_attr *parse_attr,
+				   struct pedit_headers_action *hdrs,
+				   u32 *action, struct netlink_ext_ack *extack)
+{
+	u16 mask16 = VLAN_VID_MASK;
+	u16 val16 = act->vlan.vid & VLAN_VID_MASK;
+	const struct flow_action_entry pedit_act = {
+		.id = FLOW_ACTION_MANGLE,
+		.mangle.htype = FLOW_ACT_MANGLE_HDR_TYPE_ETH,
+		.mangle.offset = offsetof(struct vlan_ethhdr, h_vlan_TCI),
+		.mangle.mask = ~(u32)be16_to_cpu(*(__be16 *)&mask16),
+		.mangle.val = (u32)be16_to_cpu(*(__be16 *)&val16),
+	};
+	int err;
+
+	if (act->vlan.prio) {
+		NL_SET_ERR_MSG_MOD(extack, "Setting VLAN prio is not supported");
+		return -EOPNOTSUPP;
+	}
+
+	err = parse_tc_pedit_action(priv, &pedit_act, namespace, parse_attr,
+				    hdrs, NULL);
+	*action |= MLX5_FLOW_CONTEXT_ACTION_MOD_HDR;
+
+	return err;
+}
+
 static int parse_tc_nic_actions(struct mlx5e_priv *priv,
 				struct flow_action *flow_action,
 				struct mlx5e_tc_flow_parse_attr *parse_attr,
@@ -2284,6 +2313,15 @@ static int parse_tc_nic_actions(struct mlx5e_priv *priv,
 			action |= MLX5_FLOW_CONTEXT_ACTION_MOD_HDR |
 				  MLX5_FLOW_CONTEXT_ACTION_FWD_DEST;
 			break;
+		case FLOW_ACTION_VLAN_MANGLE:
+			err = add_vlan_rewrite_action(priv,
+						      MLX5_FLOW_NAMESPACE_KERNEL,
+						      act, parse_attr, hdrs,
+						      &action, extack);
+			if (err)
+				return err;
+
+			break;
 		case FLOW_ACTION_CSUM:
 			if (csum_offload_supported(priv, action,
 						   act->csum_flags,
@@ -2492,8 +2530,7 @@ static int parse_tc_vlan_action(struct mlx5e_priv *priv,
 		}
 		break;
 	default:
-		/* action is FLOW_ACT_VLAN_MANGLE */
-		return -EOPNOTSUPP;
+		return -EINVAL;
 	}
 
 	attr->total_vlan = vlan_idx + 1;
@@ -2631,6 +2668,16 @@ static int parse_tc_fdb_actions(struct mlx5e_priv *priv,
 			if (err)
 				return err;
 
+			attr->split_count = attr->out_count;
+			break;
+		case FLOW_ACTION_VLAN_MANGLE:
+			err = add_vlan_rewrite_action(priv,
+						      MLX5_FLOW_NAMESPACE_FDB,
+						      act, parse_attr, hdrs,
+						      &action, extack);
+			if (err)
+				return err;
+
 			attr->split_count = attr->out_count;
 			break;
 		case FLOW_ACTION_TUNNEL_DECAP: