Re: [dpdk-dev] [PATCH v2 1/2] examples/ipsec-secgw: fix 1st pkt dropped for inline crypto

[Akhil Goyal <akhil.goyal@nxp.com>]

Hi Bernard,

On 3/26/2019 3:52 PM, Iremonger, Bernard wrote:
> Hi Akhil,
>
> <snip>
>> Subject: Re: [dpdk-dev] [PATCH v2 1/2] examples/ipsec-secgw: fix 1st pkt
>> dropped for inline crypto
>>
>> Hi Bernard,
>>
>> On 3/7/2019 8:27 PM, Bernard Iremonger wrote:
>>> Inline crypto installs a flow rule in the NIC. This flow rule must be
>>> installed before the first inbound packet is received.
>>>
>>> The create_session() function installs the flow rule,
>>> create_session() has been refactored into create_inline_session() and
>>> create_lookaside_session(). The create_inline_session() function uses
>>> the socket_ctx data and is now called at initialisation in
>>> sa_add_rules().
>> why do we need a separate function for session creation for inline and
>> lookaside cases?
>> Why can't we initialize the sessions on sa_init in both the cases?
> For the create_inline_session(struct socket_ctx *skt_ctx, struct ipsec_sa *sa) function,
> all of the required data is available in the in the skt_ctx variable.
> The skt_ctx variable is already setup when sa_init() is called.
>
> For the create_lookaside_session(struct ipsec_ctx *ipsec_ctx, struct ipsec_sa *sa) function,
> the required data is available in the ipsec_ctx variable.
>
> The ipsec_ctx variable is not setup when sa_init() is called.
> It is setup in the main_loop() function  when the variable qconf is setup.
> The main_loop() function is called after the sa_init() function is called.
>
> I hope this  answers your question
Whatever information that is required for session creation is available 
before we call the main loop() in both the cases.
My point is both the sessions(inline/lookaside) can be init at the same 
position, we do not need to have a separate path for them.
If it is not possible in sa_init(), it may be somewhere else before the 
actual data path is started.

The problem with inline processing is that, h/w need to know the SA 
before the first packet is received. So we cannot init the session on 
receive of first packet. However there is no such limitation in case of 
lookaside, it can be initialized anywhere.

-Akhil

>
> <snip>
>
> Regards,
>
> Bernard.