[dpdk-dev] [RFC] ethdev: support metadata as flow rule criteria
Ananyev, Konstantin
konstantin.ananyev at intel.com
Fri Aug 24 12:11:35 CEST 2018
> -----Original Message-----
> From: Yongseok Koh [mailto:yskoh at mellanox.com]
> Sent: Thursday, August 23, 2018 10:32 PM
> To: Andrew Rybchenko <arybchenko at solarflare.com>
> Cc: Dekel Peled <dekelp at mellanox.com>; dev at dpdk.org; orika at mellanox.com; shahafs at mellanox.com; Thomas Monjalon
> <thomas at monjalon.net>; Ananyev, Konstantin <konstantin.ananyev at intel.com>; Yigit, Ferruh <ferruh.yigit at intel.com>; Adrien
> Mazarguil <adrien.mazarguil at 6wind.com>; Olivier Matz <olivier.matz at 6wind.com>
> Subject: Re: [dpdk-dev] [RFC] ethdev: support metadata as flow rule criteria
>
> On Wed, Aug 22, 2018 at 04:31:14PM +0300, Andrew Rybchenko wrote:
> > On 13.08.2018 10:46, Dekel Peled wrote:
> > > Current implementation of rte_flow allows match pattern of flow rule,
> > > based on packet data or header fields.
> > > This limits the application use of match patterns.
> > >
> > > For example, consider a vswitch application which controls a set of VMs,
> > > connected with virtio, in a fabric with overlay of VXLAN.
> > > Several VMs can have the same inner tuple, while the outer tuple is
> > > different and controlled by the vswitch (encap action).
> > > For the vswtich to be able to offload the rule to the NIC, it must use a
> > > unique match criteria, independent from the inner tuple, to perform the
> > > encap action.
> > >
> > > This RFC adds support for additional metadata to use as match pattern.
> > > The metadata is an opaque item, fully controlled by the application.
> > >
> > > The use of metadata is relevant for egress rules only.
> > > It can be set in the flow rule using the RTE_FLOW_ITEM_META.
> > >
> > > Application should set the packet metdata in the mbuf->metadata field,
> > > and set the PKT_TX_METADATA flag in the mbuf->ol_flags.
> > > The NIC will use the packet metadata as match criteria for relevant flow
> > > rules.
> > >
> > > For example, to do an encap action depending on the VM id, the
> > > application needs to configure 'match on metadata' rte_flow rule with
> > > VM id as metadata, along with desired encap action.
> > > When preparing an egress data packet, application will set VM id data in
> > > mbuf metadata field and set PKT_TX_METADATA flag.
> > >
> > > PMD will send data packets to NIC, with VM id as metadata.
> > > Egress flow on NIC will match metadata as done with other criteria.
> > > Upon match on metadata (VM id) the appropriate encap action will be
> > > performed.
> > >
> > > This RFC introduces metadata item type for rte_flow RTE_FLOW_ITEM_META,
> > > along with corresponding struct rte_flow_item_meta and ol_flag
> > > PKT_TX_METADATA.
> > > It also enhances struct rte_mbuf with new data item, uint64_t metadata.
> > >
> > > Comments are welcome.
> > >
> > > Signed-off-by: Dekel Peled <dekelp at mellanox.com>
> > > ---
> > > doc/guides/prog_guide/rte_flow.rst | 21 +++++++++++++++++++++
> > > lib/librte_ethdev/rte_flow.c | 1 +
> > > lib/librte_ethdev/rte_flow.h | 25 +++++++++++++++++++++++++
> > > lib/librte_mbuf/rte_mbuf.h | 11 +++++++++++
> > > 4 files changed, 58 insertions(+)
> > >
> > > diff --git a/doc/guides/prog_guide/rte_flow.rst b/doc/guides/prog_guide/rte_flow.rst
> > > index b305a72..b6e35f1 100644
> > > --- a/doc/guides/prog_guide/rte_flow.rst
> > > +++ b/doc/guides/prog_guide/rte_flow.rst
> > > @@ -1191,6 +1191,27 @@ Normally preceded by any of:
> > > - `Item: ICMP6_ND_NS`_
> > > - `Item: ICMP6_ND_OPT`_
> > > +Item: ``META``
> > > +^^^^^^^^^^^^^^
> > > +
> > > +Matches an application specific 64 bit metadata item.
> > > +
> > > +- Default ``mask`` matches any 64 bit value.
> > > +
> > > +.. _table_rte_flow_item_meta:
> > > +
> > > +.. table:: META
> > > +
> > > + +----------+----------+---------------------------+
> > > + | Field | Subfield | Value |
> > > + +==========+==========+===========================+
> > > + | ``spec`` | ``data`` | 64 bit metadata value |
> > > + +----------+--------------------------------------+
> > > + | ``last`` | ``data`` | upper range value |
> > > + +----------+----------+---------------------------+
> > > + | ``mask`` | ``data`` | zeroed to match any value |
> > > + +----------+----------+---------------------------+
> > > +
> > > Actions
> > > ~~~~~~~
> > > diff --git a/lib/librte_ethdev/rte_flow.c b/lib/librte_ethdev/rte_flow.c
> > > index cff4b52..54e5ef8 100644
> > > --- a/lib/librte_ethdev/rte_flow.c
> > > +++ b/lib/librte_ethdev/rte_flow.c
> > > @@ -66,6 +66,7 @@ struct rte_flow_desc_data {
> > > sizeof(struct rte_flow_item_icmp6_nd_opt_sla_eth)),
> > > MK_FLOW_ITEM(ICMP6_ND_OPT_TLA_ETH,
> > > sizeof(struct rte_flow_item_icmp6_nd_opt_tla_eth)),
> > > + MK_FLOW_ITEM(META, sizeof(struct rte_flow_item_meta)),
> > > };
> > > /** Generate flow_action[] entry. */
> > > diff --git a/lib/librte_ethdev/rte_flow.h b/lib/librte_ethdev/rte_flow.h
> > > index f8ba71c..b81c816 100644
> > > --- a/lib/librte_ethdev/rte_flow.h
> > > +++ b/lib/librte_ethdev/rte_flow.h
> > > @@ -413,6 +413,15 @@ enum rte_flow_item_type {
> > > * See struct rte_flow_item_mark.
> > > */
> > > RTE_FLOW_ITEM_TYPE_MARK,
> > > +
> > > + /**
> > > + * [META]
> > > + *
> > > + * Matches a metadata value specified in mbuf metadata field.
> > > + *
> > > + * See struct rte_flow_item_meta.
> > > + */
> > > + RTE_FLOW_ITEM_TYPE_META,
> > > };
> > > /**
> > > @@ -849,6 +858,22 @@ struct rte_flow_item_gre {
> > > #endif
> > > /**
> > > + * RTE_FLOW_ITEM_TYPE_META.
> > > + *
> > > + * Matches a specified metadata value.
> > > + */
> > > +struct rte_flow_item_meta {
> > > + uint64_t data;
> > > +};
> > > +
> > > +/** Default mask for RTE_FLOW_ITEM_TYPE_META. */
> > > +#ifndef __cplusplus
> > > +static const struct rte_flow_item_meta rte_flow_item_meta_mask = {
> > > + .data = RTE_BE64(UINT64_MAX),
> > > +};
> > > +#endif
> > > +
> > > +/**
> > > * RTE_FLOW_ITEM_TYPE_FUZZY
> > > *
> > > * Fuzzy pattern match, expect faster than default.
> > > diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
> > > index 9ce5d76..8f06a78 100644
> > > --- a/lib/librte_mbuf/rte_mbuf.h
> > > +++ b/lib/librte_mbuf/rte_mbuf.h
> > > @@ -182,6 +182,11 @@
> > > /* add new TX flags here */
> > > /**
> > > + * This flag indicates that the metadata field in the mbuf is in use.
> > > + */
> > > +#define PKT_TX_METADATA (1ULL << 41)
> > > +
> > > +/**
> > > * UDP Fragmentation Offload flag. This flag is used for enabling UDP
> > > * fragmentation in SW or in HW. When use UFO, mbuf->tso_segsz is used
> > > * to store the MSS of UDP fragments.
> > > @@ -593,6 +598,12 @@ struct rte_mbuf {
> > > */
> > > struct rte_mbuf_ext_shared_info *shinfo;
> > > + /**
> > > + * Application specific metadata value for flow rule match.
> > > + * Valid if PKT_TX_METADATA is set.
> > > + */
> > > + uint64_t metadata;
> > > +
> >
> > I don't see the difference from hash union which is 64-bit wide as well.
> > hash.fdir.hi is used by flow mark action and mark match item (but just
> > 32-bit).
>
> Rx metadata would be different from flow mark ID. Mark ID is set when the flow
> is created (it is a kind of marking classification result) but metadata could be
> sent by other entity, e.g. VM-to-VM traffic or VM-to-HV traffic.
Ok, but it could be either rss OR flow id OR metdata (based on ol_flags) -
hash is a union after all.
Konstantin
>
> Thanks,
> Yongseok
>
> >
> > > } __rte_cache_aligned;
> > > /**
> >
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