[dpdk-dev] [PATCH v3 1/2] lib/security: add support for get metadata
Radu Nicolau
radu.nicolau at intel.com
Fri Nov 24 12:59:37 CET 2017
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.
>
> -Akhil
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