Re: [dpdk-stable] [PATCH v4 2/2] ethdev: update qfi definition

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 4/4/2021 8:45 AM, Raslan Darawsheh wrote:
> qfi field is 8 bits which represent single bit for
> PPP (paging Policy Presence) single bit for RQI
> (Reflective QoS Indicator) and 6 bits for qfi
> (QoS Flow Identifier) based on RFC 38415-g30
> 
> This update the doxygen format and the mask for qfi
> to properly identify the full 8 bits of the field.
> 
> note: changing the default mask would cause different
> patterns generated by testpmd.
> 
> Fixes: 346553db5bd1 ("ethdev: add GTP extension header to flow API")
> Cc: ying.a.wang@intel.com
> Cc: stable@dpdk.org
> 
> Signed-off-by: Raslan Darawsheh <rasland@nvidia.com>
> ---
>   doc/guides/testpmd_app_ug/testpmd_funcs.rst |  3 ++-
>   lib/librte_ethdev/rte_flow.h                | 20 +++++++++++++++++---
>   2 files changed, 19 insertions(+), 4 deletions(-)
> 
> diff --git a/doc/guides/testpmd_app_ug/testpmd_funcs.rst b/doc/guides/testpmd_app_ug/testpmd_funcs.rst
> index f59eb8a27d..dd39c4c3c2 100644
> --- a/doc/guides/testpmd_app_ug/testpmd_funcs.rst
> +++ b/doc/guides/testpmd_app_ug/testpmd_funcs.rst
> @@ -3742,7 +3742,8 @@ This section lists supported pattern items and their attributes, if any.
>   - ``gtp_psc``: match GTP PDU extension header with type 0x85.
>   
>     - ``pdu_type {unsigned}``: PDU type.
> -  - ``qfi {unsigned}``: QoS flow identifier.
> +
> +  - ``qfi {unsigned}``: PPP, RQI and QoS flow identifier.
>   
>   - ``pppoes``, ``pppoed``: match PPPoE header.
>   
> diff --git a/lib/librte_ethdev/rte_flow.h b/lib/librte_ethdev/rte_flow.h
> index 6cc57136ac..20b4389429 100644
> --- a/lib/librte_ethdev/rte_flow.h
> +++ b/lib/librte_ethdev/rte_flow.h
> @@ -20,6 +20,7 @@
>   #include <rte_arp.h>
>   #include <rte_common.h>
>   #include <rte_ether.h>
> +#include <rte_gtp.h>
>   #include <rte_icmp.h>
>   #include <rte_ip.h>
>   #include <rte_sctp.h>
> @@ -1421,16 +1422,29 @@ static const struct rte_flow_item_meta rte_flow_item_meta_mask = {
>    *
>    * Matches a GTP PDU extension header with type 0x85.
>    */
> +RTE_STD_C11
>   struct rte_flow_item_gtp_psc {
> -	uint8_t pdu_type; /**< PDU type. */
> -	uint8_t qfi; /**< QoS flow identifier. */
> +	union {
> +		struct {
> +			/*
> +			 * These fields are retained for compatibility.
> +			 * Please switch to the new header field below.
> +			 */
> +			uint8_t pdu_type; /**< PDU type. */
> +			uint8_t qfi; /**< PPP, RQI, QoS flow identifier. */
> +
> +		};
> +		struct rte_gtp_psc_hdr hdr;
> +	};
>   };

This will change the struct size even with union, since old version is missing 
all fields from protocol header. Struct size will go from 2 --> 5 bytes [1].

Since this is public struct, we can't change its size.

@Ori, Andrew,

Do you have a suggestion for next step?

- We can still add the "struct rte_gtp_psc_hdr", and add a deprecation notice 
for "struct rte_flow_item_gtp_psc" to say it will use  "struct rte_gtp_psc_hdr" 
on 21.11.

- And for this release use the Raslan's first version:
   -	uint8_t qfi; /**< QoS flow identifier. */
   +	uint8_t qfi; /**< PPP, RQI, QoS flow identifier. */


Does it make sense? Any comments?



[1]
struct rte_gtp_psc_hdr {
         uint8_t                    ext_hdr_len;          /*     0     1 */
         uint8_t                    type:4;               /*     1: 0  1 */
         uint8_t                    qmp:1;                /*     1: 4  1 */

         /* XXX 3 bits hole, try to pack */

         union {
                 struct {
                         uint8_t    snp:1;                /*     2: 0  1 */
                         uint8_t    spare_dl1:2;          /*     2: 1  1 */
                 };                                       /*     2     1 */
                 struct {
                         uint8_t    dl_delay_ind:1;       /*     2: 0  1 */
                         uint8_t    ul_delay_ind:1;       /*     2: 1  1 */
                         uint8_t    snp_ul1:1;            /*     2: 2  1 */
                 };                                       /*     2     1 */
         };                                               /*     2     1 */
         union {
                 struct {
                         uint8_t    ppp:1;                /*     3: 0  1 */
                         uint8_t    rqi:1;                /*     3: 1  1 */
                 };                                       /*     3     1 */
                 struct {
                         uint8_t    n_delay_ind:1;        /*     3: 0  1 */
                         uint8_t    spare_ul2:1;          /*     3: 1  1 */
                 };                                       /*     3     1 */
         };                                               /*     3     1 */
         uint8_t                    qfi:6;                /*     4: 0  1 */

         /* XXX 2 bits hole, try to pack */

         uint8_t                    data[];               /*     5     0 */

         /* size: 5, cachelines: 1, members: 7 */
         /* sum members: 3 */
         /* sum bitfield members: 11 bits, bit holes: 2, sum bit holes: 5 bits */
         /* last cacheline: 5 bytes */
};

>   
>   /** Default mask for RTE_FLOW_ITEM_TYPE_GTP_PSC. */
>   #ifndef __cplusplus
>   static const struct rte_flow_item_gtp_psc
>   rte_flow_item_gtp_psc_mask = {
> -	.qfi = 0x3f,
> +	.hdr.ppp = 1,
> +	.hdr.rqi = 1,
> +	.hdr.qfi = 0x3f,
>   };
>   #endif
>   
>