[PATCH 4/4] net/mlx5: refuse empty VLAN flow specification

[Nelio Laranjeiro <nelio.laranjeiro@6wind.com>]

Verbs specification does help to distinguish between packets having an VLAN
and those which do not have, this ends by having flow rule which does not
react as the user expects e.g.

 flow create 0 ingress pattern eth / vlan / end action queue index 0 / end
 flow create 0 ingress pattern eth / end action queue index 1 / end

are colliding in Verbs definition as in both rule are matching packets with
or without VLAN.
For this reason, the VLAN specification must not be empty, otherwise the
PMD has to refuse it.

Signed-off-by: Nelio Laranjeiro <nelio.laranjeiro@6wind.com>
---
 drivers/net/mlx5/mlx5_flow.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/net/mlx5/mlx5_flow.c b/drivers/net/mlx5/mlx5_flow.c
index 5c096ca9c..875a5028d 100644
--- a/drivers/net/mlx5/mlx5_flow.c
+++ b/drivers/net/mlx5/mlx5_flow.c
@@ -1305,9 +1305,18 @@ mlx5_flow_create_vlan(const struct rte_flow_item *item,
 			eth->val.vlan_tag = spec->tci;
 			eth->mask.vlan_tag = mask->tci;
 			eth->val.vlan_tag &= eth->mask.vlan_tag;
+			/*
+			 * From verbs perspective an empty VLAN is equivalent
+			 * to a packet without VLAN layer.
+			 */
+			if (!eth->mask.vlan_tag)
+				goto error;
 		}
+		return 0;
 	}
-	return 0;
+error:
+	return rte_flow_error_set(data->error, EINVAL, RTE_FLOW_ERROR_TYPE_ITEM,
+				  item, "VLAN cannot be empty");
 }
 
 /**
-- 
2.11.0