Hi Konstantin,
Please see inline.
Thanks,
Anoob
> -----Original Message-----
> From: Ananyev, Konstantin <konstantin.anan...@intel.com>
> Sent: Friday, December 13, 2019 5:25 PM
> To: Anoob Joseph <ano...@marvell.com>; Akhil Goyal <akhil.go...@nxp.com>;
> Adrien Mazarguil <adrien.mazarg...@6wind.com>; Doherty, Declan
> <declan.dohe...@intel.com>; Yigit, Ferruh <ferruh.yi...@intel.com>; Jerin
> Jacob
> Kollanukkaran <jer...@marvell.com>; Thomas Monjalon
> <tho...@monjalon.net>
> Cc: Ankur Dwivedi <adwiv...@marvell.com>; Hemant Agrawal
> <hemant.agra...@nxp.com>; Matan Azrad <ma...@mellanox.com>; Nicolau,
> Radu <radu.nico...@intel.com>; Shahaf Shuler <shah...@mellanox.com>;
> Narayana Prasad Raju Athreya <pathr...@marvell.com>; dev@dpdk.org
> Subject: [EXT] RE: [PATCH] ethdev: allow multiple security sessions to use one
> rte flow
>
> External Email
>
> ----------------------------------------------------------------------
> > > > > > The rte_security API which enables inline protocol/crypto
> > > > > > feature mandates that for every security session an rte_flow is
> > > > > > created.
> > > > > > This would internally translate to a rule in the hardware
> > > > > > which would do packet classification.
> > > > > >
> > > > > > In rte_securty, one SA would be one security session. And if
> > > > > > an rte_flow need to be created for every session, the number
> > > > > > of SAs supported by an inline implementation would be limited
> > > > > > by the number of rte_flows the PMD would be able to support.
> > > > > >
> > > > > > If the fields SPI & IP addresses are allowed to be a range,
> > > > > > then this limitation can be overcome. Multiple flows will be
> > > > > > able to use one rule for SECURITY processing. In this case,
> > > > > > the security session provided as conf would be NULL.
> > > > >
> > > > > Wonder what will be the usage model for it?
> > > > > AFAIK, RFC 4301 clearly states that either SPI value alone or
> > > > > in conjunction with dst (and src) IP should clearly identify SA
> > > > > for inbound SAD
> > > lookup.
> > > > > Am I missing something obvious here?
> > > >
> > > > [Anoob] Existing SECURITY action type requires application to
> > > > create an 'rte_flow' per SA, which is not really required if h/w
> > > > can use SPI to uniquely
> > > identify the security session/SA.
> > > >
> > > > Existing rte_flow usage: IP (dst,src) + ESP + SPI -> security
> > > > processing enabled on one security session (ie on SA)
> > > >
> > > > The above rule would uniquely identify packets for an SA. But with
> > > > the above usage, we would quickly exhaust entries available in h/w
> > > > lookup tables (which are limited on our hardware). But if h/w can
> > > > use SPI field to index
> > > into a table (for example), then the above requirement of one
> > > rte_flow per SA is not required.
> > > >
> > > > Proposed rte_flow usage: IP (any) + ESP + SPI (any) -> security
> > > > processing enabled on all ESP packets
> > > >
> > > > Now h/w could use SPI to index into a pre-populated table to get
> > > > security session. Please do note that, SPI is not ignored during
> > > > the actual
> > > lookup. Just that it is not used while creating 'rte_flow'.
> > >
> > > And this table will be prepopulated by user and pointer to it will
> > > be somehow passed via rte_flow API?
> > > If yes, then what would be the mechanism?
> >
> > [Anoob] I'm not sure what exactly you meant by user. But may be I'll explain
> how it's done in OCTEONTX2 PMD.
> >
> > The application would create security_session for every SA. SPI etc would be
> available to PMD (in conf) when the session is created.
> > Now the PMD would populate SA related params in a specific location
> > that h/w would access. This memory is allocated during device configure and
> h/w would have the pointer after the initialization is done.
> >
> > PMD uses SPI as index to write into specific locations(during session
> > create) and h/w would use it when it sees an ESP packet eligible for
> > SECURITY (in receive path, per packet). As long as session creation could
> populate at memory locations that h/w would look at, this scheme would work.
>
> Thanks for explanation, few more questions:
> Ok, so the table will be allocated at device init() somehow (nothing to do
> with
> rte_flow).
[Anoob] Yes.
> Then PMD will be able to write/update entries in that table and HW will be
> able
> to read (to get SPI, keys, etc), correct?
[Anoob] Yes.
> Now if upper layer (ipsec-secgw for example) would like to create new ESP
> session on that device, what it would need to do?
> Would it still need to use rte_flow API for that?
> Or just call rte_security_session_create() and PMD will take update this HW/SW
> table for it?
[Anoob] rte_security_session_create() is enough.
>
> >
> > >
> > > >
> > > > The usage of one 'rte_flow' for multiple SAs is not mandatory. It
> > > > is only required when application requires large number of SAs.
> > > > The proposed
> > > change is to allow more efficient usage of h/w resources where it's
> > > permitted by the PMD.
> > > >
> > > > >
> > > > > >
> > > > > > Application should do an rte_flow_validate() to make sure the
> > > > > > flow is supported on the PMD.
> > > > > >
> > > > > > Signed-off-by: Anoob Joseph <ano...@marvell.com>
> > > > > > ---
> > > > > > lib/librte_ethdev/rte_flow.h | 6 ++++++
> > > > > > 1 file changed, 6 insertions(+)
> > > > > >
> > > > > > diff --git a/lib/librte_ethdev/rte_flow.h
> > > > > > b/lib/librte_ethdev/rte_flow.h index 452d359..21fa7ed 100644
> > > > > > --- a/lib/librte_ethdev/rte_flow.h
> > > > > > +++ b/lib/librte_ethdev/rte_flow.h
> > > > > > @@ -2239,6 +2239,12 @@ struct rte_flow_action_meter {
> > > > > > * direction.
> > > > > > *
> > > > > > * Multiple flows can be configured to use the same security
> > > > > > session.
> > > > > > + *
> > > > > > + * The NULL value is allowed for security session. If
> > > > > > + security session is NULL,
> > > > > > + * then SPI field in ESP flow item and IP addresses in flow
> > > > > > + items 'IPv4' and
> > > > > > + * 'IPv6' will be allowed to be a range. The rule thus
> > > > > > + created can enable
> > > > > > + * SECURITY processing on multiple flows.
> > > > > > + *
> > > > > > */
> > > > > > struct rte_flow_action_security {
> > > > > > void *security_session; /**< Pointer to security session
> structure.
> > > > > > */
> > > > > > --
> > > > > > 2.7.4
