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

[Dekel Peled <dekelp@mellanox.com>]

Thanks, PSB.

> -----Original Message-----
> From: Stephen Hemminger <stephen@networkplumber.org>
> Sent: Tuesday, August 4, 2020 7:22 PM
> To: Dekel Peled <dekelp@mellanox.com>
> Cc: ferruh.yigit@intel.com; arybchenko@solarflare.com; Ori Kam
> <orika@mellanox.com>; Thomas Monjalon <thomas@monjalon.net>; Asaf
> Penso <asafp@mellanox.com>; Matan Azrad <matan@mellanox.com>; Eli
> Britstein <elibr@mellanox.com>; dev@dpdk.org
> Subject: Re: [dpdk-dev] [RFC] ethdev: add VLAN attributes to ETH item
> 
> 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]
> >
> https://eur03.safelinks.protection.outlook.com/?url=http%3A%2F%2Fmails
> > .dpdk.org%2Farchives%2Fdev%2F2020-
> May%2F166257.html&amp;data=02%7C01%7
> >
> Cdekelp%40mellanox.com%7Cc1ca8148f6ad42ad532708d838928c72%7Ca6529
> 71c7d
> >
> 2e4d9ba6a4d149256f461b%7C0%7C0%7C637321549359549952&amp;sdata=W
> kklrEiL
> > KzWsd4UJCt5MKlWw40qIhiVn3vUPEjzE%2BNo%3D&amp;reserved=0
> >
> > 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.
> 
I think new and existing users of this item can benefit from the new fields.

> Why not add new flow_item for vlan and handle multiple levels there.
There is already rte_flow_item_vlan available.
The proposed update is intended to clarify the use of this item.
For example pattern 'eth / ipv4 / end' can be interpreted as no-vlan, or as any-vlan.
The pattern 'eth / vlan / ipv4 / end' can be interpreted as one-vlan, or many-vlans.
The proposed update will allow specific match on vlan attributes of packet, without ambiguity.

Regards,
Dekel