Re: [dpdk-dev] [PATCH v3 4/4] ethdev: add VLAN and MPLS pop push action in flow API

[Shahaf Shuler <shahafs@mellanox.com>]

Monday, April 16, 2018 9:11 AM, Qi Zhang:
> Subject: [dpdk-dev] [PATCH v3 4/4] ethdev: add VLAN and MPLS pop push
> action in flow API
> 
> Add couple Openflow frienldy VLAN/MPLS push/pop actions.
> 
> RTE_FLOW_ACTION_VLAN_POP - pop a VLAN header.
> RTE_FLOW_ACTION_VLAN_PUSH - push a VLAN header.
> RTE_FLOW_ACTION_MPLS_POP - pop a MPLS header.
> RTE_FLOW_ACTION_MPLS_PUSH - push a MPLS header.
> 
> Signed-off-by: Qi Zhang <qi.z.zhang@intel.com>
> ---


>  /**
> @@ -1501,6 +1536,42 @@ struct rte_flow_action_ip_ttl_dec {  };
> 
>  /**
> + * RTE_FLOW_ACTION_TYPE_VLAN_PUSH,
> + *
> + * Push a new VLAN header onto the packet, Ethertype 0x8100 or 0x88a8
> + * should be used. The value of VLAN ID and VLAN priority for the new
> + * header is copied from an exist outermost VLAN header in the packet,
> + * they will be set to 0 if no such VLAN header exist.
> + */
> +struct rte_flow_action_vlan_push {
> +	rte_be16_t ether_type; /**< Ethertype for vlan tag. */ };
> +

I may have missed this also in the previous discussions.
But why limit the VLAN ID and prio to 0 if not exists? 
Why not to enable the application to define the full VLAN header it wants to push? The default, if application hasn't specified any, can be what you suggest. 

> +/**
> + * RTE_FLOW_ACTION_TYPE_MPLS_POP,
> + *
> + * Pop the outer-most MPLS header from the packet, Ethertype is
> + * required for the resulting packet if it is not the last MPLS
> + * header be popped, Ethertype must be 0x8847 or 0x8848.
> + */
> +struct rte_flow_action_mpls_pop {
> +	rte_be16_t ether_type; /**< Ethertype for MPLS header */ };
> +
> +/**
> + * RTE_FLOW_ACTION_TYPE_MPLS_PUSH,
> + *
> + * Push a new MPLS header onto the packet, Ethertype 0x8847 or 0x8848
> + * should be used. The value of MPLS label and traffic class are copied
> + * from exist outermost MPLS header, and TTL is copied from exist
> +outermost

I guess those are derived from OF spec. 

> + * MPLS or IP header, they will be set to 0, if exist packet does not
> + * contain required header.
> + */
> +struct rte_flow_action_mpls_push {
> +	rte_be16_t ether_type; /**< Ethertype for MPLS header */ };
> +

Same question as above - why not let the user to specify its MPLS header and have what you suggest as default behavior?

> +/**
>   * Definition of a single action.
>   *
>   * A list of actions is terminated by a END action.
> --
> 2.13.6