Re: [dpdk-dev] [PATCH] ethdev: add VLAN attributes to ETH and VLAN items

[Dekel Peled <dekelp@nvidia.com>]

Thanks, PSB.

> -----Original Message-----
> From: Maxime Leroy <maxime.leroy@6wind.com>
> Sent: Friday, October 2, 2020 3:39 PM
> To: Dekel Peled <dekelp@nvidia.com>
> Cc: Ori Kam <orika@nvidia.com>; NBU-Contact-Thomas Monjalon
> <thomas@monjalon.net>; ferruh.yigit@intel.com;
> arybchenko@solarflare.com; dev@dpdk.org; Dekel Peled
> <dekelp@mellanox.com>
> Subject: Re: [PATCH] ethdev: add VLAN attributes to ETH and VLAN items
> 
> Hi Dekel,
> 
> On Thu, Oct 1, 2020 at 8:49 PM Dekel Peled <dekelp@nvidia.com> wrote:
> >
> > From: Dekel Peled <dekelp@mellanox.com>
> >
> > This patch implements the change proposes in RFC [1], adding dedicated
> > fields to ETH and VLAN items structs, to clearly define the required
> > characteristic of a packet, and enable precise match criteria.
> >
> > [1]
> >
> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fmail
> > s.dpdk.org%2Farchives%2Fdev%2F2020-
> August%2F177536.html&amp;data=02%7C
> >
> 01%7Cdekelp%40nvidia.com%7Cc12bfd3f662747f7b7c408d866d0376f%7C430
> 83d15
> >
> 727340c1b7db39efd9ccc17a%7C0%7C0%7C637372391779092411&amp;sdata=
> yeOKvc
> > 4r0dL09UZ65%2Bt4qWJqJmcp21VyPSK%2FhbablKI%3D&amp;reserved=0
> >
> > Signed-off-by: Dekel Peled <dekelp@mellanox.com>
> > ---
> >  doc/guides/rel_notes/release_20_11.rst |  7 +++++++
> >  lib/librte_ethdev/rte_flow.h           | 16 +++++++++++++---
> >  2 files changed, 20 insertions(+), 3 deletions(-)
> >
> > diff --git a/doc/guides/rel_notes/release_20_11.rst
> > b/doc/guides/rel_notes/release_20_11.rst
> > index 7f9d0dd..199c60b 100644
> > --- a/doc/guides/rel_notes/release_20_11.rst
> > +++ b/doc/guides/rel_notes/release_20_11.rst
> > @@ -173,6 +173,13 @@ API Changes
> >    * ``_rte_eth_dev_callback_process()`` ->
> ``rte_eth_dev_callback_process()``
> >    * ``_rte_eth_dev_reset`` -> ``rte_eth_dev_internal_reset()``
> >
> > +* ethdev: Added new field ``vlan_exist`` to structure
> > +``rte_flow_item_eth``,
> > +  indicating that at least one VLAN exists in the packet header.
> > +
> > +* ethdev: Added new field ``more_vlans_exist`` to structure
> > +  ``rte_flow_item_vlan``, indicating that at least one more VLAN
> > +exists in
> > +  packet header, following this VLAN.
> > +
> >  * rawdev: Added a structure size parameter to the functions
> >    ``rte_rawdev_queue_setup()``, ``rte_rawdev_queue_conf_get()``,
> >    ``rte_rawdev_info_get()`` and ``rte_rawdev_configure()``, diff
> > --git a/lib/librte_ethdev/rte_flow.h b/lib/librte_ethdev/rte_flow.h
> > index da8bfa5..39d04ef 100644
> > --- a/lib/librte_ethdev/rte_flow.h
> > +++ b/lib/librte_ethdev/rte_flow.h
> > @@ -723,14 +723,18 @@ struct rte_flow_item_raw {
> >   * If the @p type field contains a TPID value, then only tagged packets with
> the
> >   * specified TPID will match the pattern.
> >   * Otherwise, only untagged packets will match the pattern.
> > - * 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 field @p vlan_exist can be used to match specific packet
> > + types, instead
> > + * of using the @p type field.
> > + * This can be used to match any type of tagged packets.
> > + * If the @p type and @p vlan_exist fields are not specified, then
> > + both tagged
> > + * and untagged packets will match the pattern.
> >   */
> >  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 vlan_exist:1; /**< At least one VLAN exist in header. */
> > +       uint32_t reserved:31; /**< Reserved, must be zero. */
> >  };
> 
> To resume:
> - type and vlan_exists fields not specified:  tag and untagged matched
> - with vlan_exists, match only tag or untagged
> - with type matching specific ethernet type
> - vlan_exists and type should not setted at the same time ?

PMD should validate they don't conflict.

> 
> With this new specification, I think you address all the use cases.
> That's great !
> 

Glad to see we agree on this.

> >
> >  /** Default mask for RTE_FLOW_ITEM_TYPE_ETH. */ @@ -752,10 +756,16
> @@
> > struct rte_flow_item_eth {
> >   * the preceding pattern item.
> >   * If a @p VLAN item is present in the pattern, then only tagged packets
> will
> >   * match the pattern.
> > + * The field @p more_vlans_exist can be used to match specific packet
> > + types,
> > + * instead of using the @p inner_type field.
> > + * This can be used to match any type of tagged packets.
> >   */
> 
> Could you please specify what the expected behavior when inner_type and
> more_vlans_exist are not specified .
> What is the default behavior ?
> 

You wrote above for the eth item, if the user didn't specify it means don't-care.

> >  struct rte_flow_item_vlan {
> >         rte_be16_t tci; /**< Tag control information. */
> >         rte_be16_t inner_type; /**< Inner EtherType or TPID. */
> > +       uint32_t more_vlans_exist:1;
> > +       /**< At least one more VLAN exist in header, following this VLAN. */
> > +       uint32_t reserved:31; /**< Reserved, must be zero. */
> >  };
> >
> >  /** Default mask for RTE_FLOW_ITEM_TYPE_VLAN. */
> > --
> > 1.8.3.1
> >
> 
> I am still wondering, why not using a new item 'NOT' for example to match
> only eth packet not tagged ?
> example: eth / not vlan. It's a more generic solution.
> 
> Here in this commit, we add a reference on VLAN fields on ethernet header.
> But tomorrow, we could do the same for mpls by adding mpls_exists in the
> eth item and so on.
> 
> In fact, we  have the same needs for IPv6 options. To match for example,
> ipv6 packet with no fragment option.
> With a NOT field, it can be easily done: > eth / ipv6 / no ipv6_frag.
> 
> Adding new fields 'item'_exists into eth and ipv6 do the jobs, but having a
> NOT attribute is a more generic solution.
> 
> It could address many other use cases like matching any udp packets that are
> not vxlan ( eth / ipv4 / vxlan / not udp),
> 
> Let me know what you think about that.

I agree with Thomas Monjalon response on this.

> 
> Regards,
> 
> Maxime