net/mlx5: reject inner ethernet matching in GTP

[ upstream commit 4e5ba38 ]

The user is able to create a flow rule pattern with ETH after GTP
although it is not supported by the flex-parser configuration.

Failed the rule validation in such case with proper error message.

Fixes: 23c1d42 ("net/mlx5: split flow validation to dedicated function")

Signed-off-by: Lior Margalit <lmargalit@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>

drivers/net/mlx5/mlx5_flow.c

@@ -1914,6 +1914,10 @@ mlx5_flow_validate_item_eth(const struct rte_flow_item *item,
 		return rte_flow_error_set(error, EINVAL,
 					  RTE_FLOW_ERROR_TYPE_ITEM, item,
 					  "L2 layer should not follow VLAN");
+	if (item_flags & MLX5_FLOW_LAYER_GTP)
+		return rte_flow_error_set(error, EINVAL,
+					  RTE_FLOW_ERROR_TYPE_ITEM, item,
+					  "L2 layer should not follow GTP");
 	if (!mask)
 		mask = &rte_flow_item_eth_mask;
 	ret = mlx5_flow_item_acceptable(item, (const uint8_t *)mask,