Re: [dpdk-dev] [EXT] Re: [PATCH] ethdev: allow multiple security sessions to use one rte flow

Wed, 18 Dec 2019 05:53:29 -0800 

Hi Anoob,

On 18/12/2019 03:54, Anoob Joseph wrote:

Hi Vladimir,

Please see inline.

Thanks,
Anoob


-----Original Message-----
From: Medvedkin, Vladimir <vladimir.medved...@intel.com>
Sent: Tuesday, December 17, 2019 11:14 PM
To: Anoob Joseph <ano...@marvell.com>; Ananyev, Konstantin
<konstantin.anan...@intel.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: Re: [EXT] Re: [dpdk-dev] [PATCH] ethdev: allow multiple security
sessions to use one rte flow

Hi Anoob,

On 17/12/2019 14:24, Anoob Joseph wrote:

Hi Vladimir,

Please see inline.

Thanks,
Anoob


-----Original Message-----
From: Medvedkin, Vladimir <vladimir.medved...@intel.com>
Sent: Tuesday, December 17, 2019 4:51 PM
To: Anoob Joseph <ano...@marvell.com>; Ananyev, Konstantin
<konstantin.anan...@intel.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: Re: [EXT] Re: [dpdk-dev] [PATCH] ethdev: allow multiple
security sessions to use one rte flow

Hi Anoob,

On 16/12/2019 16:16, Anoob Joseph wrote:

Hi Vladimir,

Please see inline.

Thanks,
Anoob


-----Original Message-----
From: Medvedkin, Vladimir <vladimir.medved...@intel.com>
Sent: Monday, December 16, 2019 9:29 PM
To: Anoob Joseph <ano...@marvell.com>; Ananyev, Konstantin
<konstantin.anan...@intel.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: [dpdk-dev] [PATCH] ethdev: allow multiple
security sessions to use one rte flow

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Hi Anoob,

On 11/12/2019 17:33, Anoob Joseph wrote:

Hi Konstantin,

Please see inline.

Thanks,
Anoob


-----Original Message-----
From: dev <dev-boun...@dpdk.org> On Behalf Of Ananyev,

Konstantin

Sent: Wednesday, December 11, 2019 4:36 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: Re: [dpdk-dev] [PATCH] ethdev: allow multiple security
sessions to use one rte flow



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

So this means that SA will be indexed only by spi? What about SA's
which are indexed by SPI+DIP+SIP?

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.
If memory is allocated during device configure what is upper limit
for number of sessions? What if app needs more?

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.

[Anoob] Yes. But we need to allow application to control the h/w
ipsec

processing as well. Let's say, application wants to handle a specific
SPI range in lookaside mode (may be because of unsupported
capabilities?), in that case having rte_flow will help in fine tuning how the

h/w packet steering happens.

Also, rte_flow enables H/w parsing on incoming packets. This info is
useful even after IPsec processing is complete. Or if application
wants to give higher priority to a range of SPIs, rte_flow would allow doing

so.

What algorithm of indexing by SPI is there? Could I use any
arbitrary SPI? If some kind of hashing is used, what about collisions?

[Anoob] That is implementation dependent. In our PMD, we map it one

to one.

As in, SPI is used as index in the table.
So, as far as you are mapping one to one and using SPI as an index, a
lot of memory is wasted in the table for unused SPI's.  Also, you are
not able to have a table with 2^32 sessions. It is likely that some
number of SPI's least significant bits are used as an index. And it
raises a question - what if application needs two sessions with different

SPI's which have the same lsb's?

[Anoob] rte_security_session_create() would fail. Why do you say we

cannot support 2^32 sessions? If it's memory limitation, the same memory
limitation would apply even if you have dynamic allocation of memory for
sessions. So at some point session creation would start failing. In our PMD,
we allow user to specify the range it requires using devargs.

Also, collision of LSBs can be avoided by introducing a "MARK" rule in

addition to "SECURITY" for the rte_flow created for inline ipsec. Currently
that model is not supported (in the library), but that is one solution to the
collisions that can be pursued later.

Moreover, what about
two sessions with same SPI but different dst and src ip addresses?

[Anoob] Currently our PMD only support UCAST IPSEC. So another session

with same SPI would result in session creation failure.

Aha, I see, thanks for the explanation. So my suggestion here would be:

- Application defines that some subset of SA's would be inline protocol
processed. And this SA's will be indexed by SPI only.

- App defines special range for SPI values of this SA's (size of this range is
defined using devargs) and first SPI value (from configuration?).

- App installs rte_flow only for this range (from first SPI to first SPI
+ range size), not for all SPI values.

[Anoob] This is exactly what this patch proposes. Allowing the SPI and the IP 
addresses to be range and have security_session provided as NULL. What you have 
described would be achievable only if we can allow this modification in the lib.

So can I assume you are in agreement with this patch?


Not exactly. I meant it is better to make more specified flow like:

...

struct rte_flow_item_esp esp_spec = {

        .hdr = {
                .spi = rte_cpu_to_be_32(first_spi),
        },

};

struct rte_flow_item_esp esp_mask = {

        .hdr = {
                .spi = rte_cpu_to_be_32(nb_ipsec_in_sa - 1),
        },

};

pattern[0].type = RTE_FLOW_ITEM_TYPE_ESP;

pattern[0].spec = & esp_spec;

pattern[0].mask = &esp_mask;

...
So this means inline proto device would process only special subset of SPI's. All other will be processed as usual. Sure, you can assign all 2^32 SPI range and it work as you intended earlier. I think we need to have finer grained control here. 


- Other SPI values would be processed non inline.

In this case we would be able to have SA addressed by longer tuple (i.e.
SPI+DIP+SIP) outside of before mentioned range, as well as SA with
unsupported capabilities by inline protocol device.


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

--
Regards,
Vladimir

--
Regards,
Vladimir

--
Regards,
Vladimir


--
Regards,
Vladimir

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