[dpdk-dev] [PATCH v4 1/2] ethdev: add new ext hdr for gtp psc

[Ferruh Yigit]

On 4/8/2021 1:37 PM, Raslan Darawsheh wrote:
> Hi Olivier,
> 
>> -----Original Message-----
>> From: Olivier Matz <olivier.matz at 6wind.com>
>> Sent: Thursday, April 8, 2021 3:30 PM
>> To: Raslan Darawsheh <rasland at nvidia.com>
>> Cc: dev at dpdk.org; ferruh.yigit at intel.com; Ori Kam <orika at nvidia.com>;
>> andrew.rybchenko at oktetlabs.ru; ivan.malov at oktetlabs.ru;
>> ying.a.wang at intel.com; Slava Ovsiienko <viacheslavo at nvidia.com>; Shiri
>> Kuzin <shirik at nvidia.com>
>> Subject: Re: [PATCH v4 1/2] ethdev: add new ext hdr for gtp psc
>>
>> Hi Raslan,
>>
>> On Sun, Apr 04, 2021 at 10:45:51AM +0300, Raslan Darawsheh wrote:
>>> Define new rte header for gtp PDU session container
>>> based on RFC 38415-g30
>>
>> Do you have a link to this RFC?
> Yes sure,
> https://www.3gpp.org/ftp/Specs/archive/38_series/38.415/38415-g30.zip
> 
>>
>>> Signed-off-by: Raslan Darawsheh <rasland at nvidia.com>
>>> ---
>>>   lib/librte_net/rte_gtp.h | 34 ++++++++++++++++++++++++++++++++++
>>>   1 file changed, 34 insertions(+)
>>>
>>> diff --git a/lib/librte_net/rte_gtp.h b/lib/librte_net/rte_gtp.h
>>> index 6a6f9b238d..088b0b5a53 100644
>>> --- a/lib/librte_net/rte_gtp.h
>>> +++ b/lib/librte_net/rte_gtp.h
>>> @@ -61,6 +61,40 @@ struct rte_gtp_hdr_ext_word {
>>>   	uint8_t next_ext;     /**< Next Extension Header Type. */
>>>   }  __rte_packed;
>>>
>>> +/**
>>> + * Optional extension for GTP with next_ext set to 0x85
>>> + * defined based on RFC 38415-g30.
>>> + */
>>> +__extension__
>>> +struct rte_gtp_psc_hdr {
>>> +	uint8_t ext_hdr_len; /**< PDU ext hdr len in multiples of 4 bytes */
>>> +	uint8_t type:4; /**< PDU type */
>>> +	uint8_t qmp:1; /**< Qos Monitoring Packet */
>>> +	union {
>>> +		struct {
>>> +			uint8_t snp:1; /**< Sequence number presence */
>>> +			uint8_t spare_dl1:2; /**< spare down link bits */
>>> +		};
>>> +		struct {
>>> +			uint8_t dl_delay_ind:1; /**< dl delay result presence
>> */
>>> +			uint8_t ul_delay_ind:1; /**< ul delay result presence
>> */
>>> +			uint8_t snp_ul1:1; /**< Sequence number presence
>> ul */
>>> +		};
>>> +	};
>>> +	union {
>>> +		struct {
>>> +			uint8_t ppp:1; /**< Paging policy presence */
>>> +			uint8_t rqi:1; /**< Reflective Qos Indicator */
>>> +		};
>>> +		struct {
>>> +			uint8_t n_delay_ind:1; /**< N3/N9 delay result
>> presence */
>>> +			uint8_t spare_ul2:1; /**< spare up link bits */
>>> +		};
>>> +	};
>>> +	uint8_t qfi:6; /**< Qos Flow Identifier */
>>> +	uint8_t data[0]; /**< data feilds */
>>> +} __rte_packed;
>>
>> With this header, sizeof(rte_gtp_psc_hdr) = 5, is it really expected?
> The data[0] is variable length data, I guess I should send another version to mention that in the comment maybe.
> The header size according to the spec should be 4 octets aligned in general.

The struct is 5 btyes, this is not related to data[0], please check the pahole 
output:
http://inbox.dpdk.org/dev/536631b9-c634-ddac-c154-91978ffc29a5@intel.com/

>>
>> It would help to see the specification to have a better idea of how to
> Sure, I've just posted the link above, please let me know of any suggestion that you have, and I'll be glad to do accordingly.
> 
>> split, but a possible solution is to do something like this:
>>
>> struct rte_gtp_psc_generic_hdr {
>> 	uint8_t ext_hdr_len;
>> 	uint8_t type:4
>> 	uint8_t qmp:1;
>> 	uint8_t pad:3;
>> };
>>
>> struct rte_gtp_psc_<name1>_hdr {
>> 	uint8_t ext_hdr_len;
>> 	uint8_t type:4
>> 	uint8_t qmp:1;
>> 	uint8_t uint8_t snp:1;
>> 	uint8_t spare_dl1:2;
>> 	...
>> };
>>
>> ...
>>
>> struct rte_gtp_psc_hdr {
>> 	union {
>> 		struct rte_gtp_psc_generic_hdr generic;
>> 		struct rte_gtp_psc_<name1>_hdr <name1>;
>> 		struct rte_gtp_psc_<name2>_hdr <name2>;
>> 	};
>> };
>>
>> Also, you need to take care about endianness.
>>
>>
>> Regards,
>> Olivier
> Kindest regards
> Raslan Darawsheh
>