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

[Ferruh Yigit]

On 4/13/2021 10:24 AM, Ori Kam wrote:
Hi Raslan,
-----Original Message-----
From: Raslan Darawsheh <rasl...@nvidia.com>
Subject: RE: [PATCH v4 2/2] ethdev: update qfi definition

Hi,

-----Original Message-----
From: Ferruh Yigit <ferruh.yi...@intel.com>
Sent: Tuesday, April 6, 2021 7:10 PM
To: Raslan Darawsheh <rasl...@nvidia.com>; dev@dpdk.org; Ori Kam
<or...@nvidia.com>; andrew.rybche...@oktetlabs.ru
Cc: ivan.ma...@oktetlabs.ru; ying.a.w...@intel.com;
olivier.m...@6wind.com; Slava Ovsiienko <viachesl...@nvidia.com>; Shiri
Kuzin <shi...@nvidia.com>; sta...@dpdk.org; David Marchand
<david.march...@redhat.com>; NBU-Contact-Thomas Monjalon
<tho...@monjalon.net>
Subject: Re: [PATCH v4 2/2] ethdev: update qfi definition

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.w...@intel.com
Cc: sta...@dpdk.org

Signed-off-by: Raslan Darawsheh <rasl...@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?


I think Ferruh is right, and I think that we should at this point just update 
the documentation.
Sorry for the detour
Just small comment about the original  patch.
I don’t think you should change the default mask since it may break existing 
apps.


I will continue with first patch [1], and will update the protocol reference in 
the commit log.

Meanwhile adding 'struct rte_gtp_psc_hdr' (patch v4 1/2) work can continue 
separately.
And when it is added we can send a deprecation notice to update 'struct 
rte_flow_item_gtp_psc' and finally update it on v21.11 to have 'struct 
rte_gtp_psc_hdr' in it. Makes sense?

[1]
https://patches.dpdk.org/project/dpdk/patch/20210323121134.19113-1-rasl...@nvidia.com/

- 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?

@Ori Kam, @andrew.rybche...@oktetlabs.ru,
This is a kind remainder of this patch,



[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