Re: [dpdk-dev] [RFC v2 5/9] ipsec: add SA data-path API

[Jerin Jacob <jerin.jacob@caviumnetworks.com>]

-----Original Message-----
> Date: Sun, 28 Oct 2018 20:37:23 +0000
> From: "Ananyev, Konstantin" <konstantin.ananyev@intel.com>
> To: Jerin Jacob <jerin.jacob@caviumnetworks.com>
> CC: "dev@dpdk.org" <dev@dpdk.org>, "Awal, Mohammad Abdul"
>  <mohammad.abdul.awal@intel.com>, "Joseph, Anoob"
>  <Anoob.Joseph@cavium.com>, "Athreya, Narayana Prasad"
>  <NarayanaPrasad.Athreya@cavium.com>
> Subject: RE: [dpdk-dev] [RFC v2 5/9] ipsec: add SA data-path API
> 

> 
> Hi Jerin,

Hi Konstantin,

> 
> > > > > +
> > > > > +/**
> > > > > + * Checks that inside given rte_ipsec_session crypto/security fields
> > > > > + * are filled correctly and setups function pointers based on these values.
> > > > > + * @param ss
> > > > > + *   Pointer to the *rte_ipsec_session* object
> > > > > + * @return
> > > > > + *   - Zero if operation completed successfully.
> > > > > + *   - -EINVAL if the parameters are invalid.
> > > > > + */
> > > > > +int __rte_experimental
> > > > > +rte_ipsec_session_prepare(struct rte_ipsec_session *ss);
> > > > > +
> > > > > +/**
> > > > > + * For input mbufs and given IPsec session prepare crypto ops that can be
> > > > > + * enqueued into the cryptodev associated with given session.
> > > > > + * expects that for each input packet:
> > > > > + *      - l2_len, l3_len are setup correctly
> > > > > + * Note that erroneous mbufs are not freed by the function,
> > > > > + * but are placed beyond last valid mbuf in the *mb* array.
> > > > > + * It is a user responsibility to handle them further.
> > > > > + * @param ss
> > > > > + *   Pointer to the *rte_ipsec_session* object the packets belong to.
> > > > > + * @param mb
> > > > > + *   The address of an array of *num* pointers to *rte_mbuf* structures
> > > > > + *   which contain the input packets.
> > > > > + * @param cop
> > > > > + *   The address of an array of *num* pointers to the output *rte_crypto_op*
> > > > > + *   structures.
> > > > > + * @param num
> > > > > + *   The maximum number of packets to process.
> > > > > + * @return
> > > > > + *   Number of successfully processed packets, with error code set in rte_errno.
> > > > > + */
> > > > > +static inline uint16_t __rte_experimental
> > > > > +rte_ipsec_crypto_prepare(const struct rte_ipsec_session *ss,
> > > > > +       struct rte_mbuf *mb[], struct rte_crypto_op *cop[], uint16_t num)
> > > > > +{
> > > > > +       return ss->func.prepare(ss, mb, cop, num);
> > > > > +}
> > > > > +
> > > > static inline uint16_t __rte_experimental
> > > > rte_ipsec_event_process(const struct rte_ipsec_session *ss, struct rte_event *ev[], uint16_t num)
> > > > {
> > > >        return ss->func.event_process(ss, ev, num);
> > > > }
> > >
> > > To fulfill that, we can either have 2 separate function pointers:
> > > uint16_t (*pkt_process)( const struct rte_ipsec_session *ss, struct rte_mbuf *mb[],uint16_t num);
> > > uint16_t (*event_process)( const struct rte_ipsec_session *ss, struct rte_event *ev[],uint16_t num);
> > >
> > > Or we can keep one function pointer, but change it to accept just array of pointers:
> > > uint16_t (*process)( const struct rte_ipsec_session *ss, void *in[],uint16_t num);
> > > and then make session_prepare() to choose a proper function based on input.
> > >
> > > I am ok with both schemes, but second one seems a bit nicer to me.
> >
> > How about best of both worlds, i.e save space and enable compile check
> > by anonymous union of both functions
> >
> > RTE_STD_C11
> > union {
> >       uint16_t (*pkt_process)( const struct rte_ipsec_session *ss,struct rte_mbuf *mb[],uint16_t num);
> >       uint16_t (*event_process)( const struct rte_ipsec_session *ss, struct rte_event *ev[],uint16_t num);
> > };
> >
> 
> Yes, it is definitely possible, but then we still need 2 API functions,
> Depending on input type, i.e:
> 
> static inline uint16_t __rte_experimental
> rte_ipsec_event_process(const struct rte_ipsec_session *ss, struct rte_event *ev[], uint16_t num)
>  {
>         return ss->func.event_process(ss, ev, num);
> }
> 
> static inline uint16_t __rte_experimental
> rte_ipsec_pkt_process(const struct rte_ipsec_session *ss, struct rte_mbuf *mb[], uint16_t num)
>  {
>         return ss->func.pkt_process(ss, mb, num);
> }
> 
> While if we'll have void *[], we can have just one function for both cases:
> 
> static inline uint16_t __rte_experimental
> rte_ipsec_process(const struct rte_ipsec_session *ss, void *in[], uint16_t num)
>  {
>         return ss->func.process(ss, in, num);
> }

Since it will be called from different application code path. I would
prefer to have separate functions to allow strict compiler check.



> 
> Konstantin