[dpdk-dev] [PATCH v3 1/2] lib/security: add support for get metadata
Akhil Goyal
akhil.goyal at nxp.com
Fri Nov 24 13:03:47 CET 2017
On 11/24/2017 5:29 PM, Radu Nicolau wrote:
>
>
> On 11/24/2017 11:34 AM, Akhil Goyal wrote:
>> Hi Radu,
>> On 11/24/2017 4:47 PM, Radu Nicolau wrote:
>>>
>>>
>>> On 11/24/2017 10:55 AM, Akhil Goyal wrote:
>>>> On 11/24/2017 3:09 PM, Radu Nicolau wrote:
>>>>> Hi,
>>>>>
>>>>> Comment inline
>>>>>
>>>>>
>>>>> On 11/24/2017 8:50 AM, Akhil Goyal wrote:
>>>>>> Hi Anoob, Radu,
>>>>>> On 11/23/2017 4:49 PM, Anoob Joseph wrote:
>>>>>>> In case of inline protocol processed ingress traffic, the packet
>>>>>>> may not
>>>>>>> have enough information to determine the security parameters with
>>>>>>> which
>>>>>>> the packet was processed. In such cases, application could get
>>>>>>> metadata
>>>>>>> from the packet which could be used to identify the security
>>>>>>> parameters
>>>>>>> with which the packet was processed.
>>>>>>>
>>>>>>> Signed-off-by: Anoob Joseph <anoob.joseph at caviumnetworks.com>
>>>>>>> ---
>>>>>>> v3:
>>>>>>> * Replaced 64 bit metadata in conf with (void *)userdata
>>>>>>> * The API(rte_security_get_pkt_metadata) would return void *
>>>>>>> instead of
>>>>>>> uint64_t
>>>>>>>
>>>>>>> v2:
>>>>>>> * Replaced get_session and get_cookie APIs with get_pkt_metadata API
>>>>>>>
>>>>>>> lib/librte_security/rte_security.c | 13 +++++++++++++
>>>>>>> lib/librte_security/rte_security.h | 19 +++++++++++++++++++
>>>>>>> lib/librte_security/rte_security_driver.h | 16 ++++++++++++++++
>>>>>>> 3 files changed, 48 insertions(+)
>>>>>>>
>>>>>>> diff --git a/lib/librte_security/rte_security.c
>>>>>>> b/lib/librte_security/rte_security.c
>>>>>>> index 1227fca..a1d78b6 100644
>>>>>>> --- a/lib/librte_security/rte_security.c
>>>>>>> +++ b/lib/librte_security/rte_security.c
>>>>>>> @@ -108,6 +108,19 @@ rte_security_set_pkt_metadata(struct
>>>>>>> rte_security_ctx *instance,
>>>>>>> sess, m, params);
>>>>>>> }
>>>>>>> +void *
>>>>>>> +rte_security_get_pkt_metadata(struct rte_security_ctx *instance,
>>>>>>> + struct rte_mbuf *pkt)
>>>>>> Can we rename pkt with m. Just to make it consistent with the set
>>>>>> API.
>>>>>>> +{
>>>>>>> + void *md = NULL;
>>>>>>> +
>>>>>>> + RTE_FUNC_PTR_OR_ERR_RET(*instance->ops->get_pkt_metadata, NULL);
>>>>>>> + if (instance->ops->get_pkt_metadata(instance->device, pkt,
>>>>>>> &md))
>>>>>>> + return NULL;
>>>>>>> +
>>>>>>> + return md;
>>>>>>> +}
>>>>>>
>>>>>> Pkt metadata should be set by user i.e. the application, and the
>>>>>> driver need not be aware of the format and the values of the
>>>>>> metadata.
>>>>>> So setting the metadata in the driver and getting it back from the
>>>>>> driver does not look a good idea.
>>>>>>
>>>>>> Is it possible, that the application define the metadata on its
>>>>>> own and set it in the library itself without the call to the
>>>>>> driver ops.
>>>>> I'm not sure I understand here; even in our case (ixgbe) the driver
>>>>> sets the metadata and it is aware of the format - that is the whole
>>>>> idea. This is why we added the set_metadata API, to allow the
>>>>> driver to inject extra information into the mbuf, information that
>>>>> is driver specific and derived from the security session, so it
>>>>> makes sense to also have a symmetric get_metadata.
>>>>> Private data is the one that follows those rules, i.e. application
>>>>> specific and driver transparent.
>>>>
>>>> As per my understanding of the user metadata, it should be in
>>>> control of the application, and the application shall know the
>>>> format of that. Setting in driver will disallow this.
>>>> Please let me know if my understanding is incorrect.
>>>>
>>>> If at all, some information is needed to be set on the basis of
>>>> driver, then application can get that information from the driver
>>>> and then set it in the packet metadata in its own way/format.
>>>
>>> The rte_security_set_pkt_metadata() doc defines the metadata as
>>> "device-specific defined metadata" and also takes a device specific
>>> params pointer, so the symmetric function is to be expected to work
>>> in the same way, i.e. return device specific metadata associated with
>>> the security session and instance and mbuf. How is this metadata
>>> stored is not specified in the security API, so the PMD
>>> implementation have the flexibility.
>>>
>>
>> Yes it was defined that way and I did not noticed this one at the time
>> of it's implementation.
>> Here, my point is that the application may be using mbuf udata for
>> it's own functionality, it should not be modified in the driver.
>>
>> However, if we need to do this, then we may need to clarify in the
>> documentation that for security, udata shall be set with the
>> rte_security_set_pkt_metadata() and not otherwise.
> Indeed, we should update the doc stating that the set_metadata may
> change the mbuf userdata field so the application should use only
> private data if needed.
Agreed, but it is dependent on which driver/mode(inline or lookaside),
it will be used.
Lookaside may not need this API as of now. Other implementations may
also don't require. So this shall be documented that way.
-Akhil
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