Re: [dpdk-dev] [RFC] ethdev: add VLAN attributes to ETH item

[Stephen Hemminger <stephen@networkplumber.org>]

On Tue,  4 Aug 2020 18:36:20 +0300
Dekel Peled <dekelp@mellanox.com> wrote:

> In existing code the match on tagged/untagged packets is not explicit.
> Recent documentation update [1] describes the different patterns and
> clarifies the intended use of different patterns.
> 
> This patch proposes an update to ETH item struct, to clearly define the
> required characteristic of a packet, and enable precise match criteria.
> 
> [1] http://mails.dpdk.org/archives/dev/2020-May/166257.html
> 
> Signed-off-by: Dekel Peled <dekelp@mellanox.com>
> ---
>  lib/librte_ethdev/rte_flow.h | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/lib/librte_ethdev/rte_flow.h b/lib/librte_ethdev/rte_flow.h
> index cf0eccb..345feb5 100644
> --- a/lib/librte_ethdev/rte_flow.h
> +++ b/lib/librte_ethdev/rte_flow.h
> @@ -726,11 +726,20 @@ struct rte_flow_item_raw {
>   * If the @p ETH item is the only item in the pattern, and the @p type field
>   * is not specified, then both tagged and untagged packets will match the
>   * pattern.
> + * The fields @p cvlan_exist and @p svlan_exist can be used to match specific
> + * packet types, instead of using the @p type field. This can be used to match
> + * on packets that do/don't contain either cvlan, svlan, or both.
> + * The field @p num_of_vlans can be used to match packets by the exact number
> + * of VLANs in header.
>   */
>  struct rte_flow_item_eth {
>  	struct rte_ether_addr dst; /**< Destination MAC. */
>  	struct rte_ether_addr src; /**< Source MAC. */
>  	rte_be16_t type; /**< EtherType or TPID. */
> +	uint32_t cvlan_exist:1; /**< C-tag VLAN exist in header. */
> +	uint32_t svlan_exist:1; /**< S-tag VLAN exist in header. */
> +	uint32_t reserved:14; /**< Reserved, must be zero. */
> +	uint32_t num_of_vlans:16; /**< Number of VLANs in header. */
>  };
>  
>  /** Default mask for RTE_FLOW_ITEM_TYPE_ETH. */

You are making life easy for you but harder for existing
users of flow_item_eth API.

Why not add new flow_item for vlan and handle multiple levels there.