RE: [PATCH] app/testpmd: fix IPv6 tunnel packet checksum error

["He, ShiyangX" <shiyangx.he@intel.com>]

>-----Original Message-----
>From: Ferruh Yigit <ferruh.yigit@amd.com>
>Sent: Friday, June 2, 2023 6:10 AM
>To: He, ShiyangX <shiyangx.he@intel.com>; dev@dpdk.org
>Cc: Zhou, YidingX <yidingx.zhou@intel.com>; stable@dpdk.org; Singh, Aman
>Deep <aman.deep.singh@intel.com>; Zhang, Yuying
><yuying.zhang@intel.com>; Somnath Kotur
><somnath.kotur@broadcom.com>; Andrew Rybchenko
><andrew.rybchenko@oktetlabs.ru>; Matz, Olivier <olivier.matz@6wind.com>;
>Ajit Khaparde <ajit.khaparde@broadcom.com>
>Subject: Re: [PATCH] app/testpmd: fix IPv6 tunnel packet checksum error
>
>On 5/30/2023 4:36 PM, Shiyang He wrote:
>> In checksum forwarding mode, the checksum of tunnel packet calculated
>> incorrectly when outer header is IPv6.
>>
>> This patch fixes the issue by setting L4 checksum flag.
>>
>> Fixes: daa02b5cddbb ("mbuf: add namespace to offload flags")
>
>This commit just updates the flag name, actual commit that introduce the
>commit should be something else.
>
>Probably:
>Fixes: c14236f210d8 ("mbuf: replace inner fields by outer fields semantic")
>Cc: jijiang.liu@intel.com
>
>
>> Cc: stable@dpdk.org
>>
>> Signed-off-by: Shiyang He <shiyangx.he@intel.com>
>> ---
>>  app/test-pmd/csumonly.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/app/test-pmd/csumonly.c b/app/test-pmd/csumonly.c index
>> fc85c22a77..bd2fccc458 100644
>> --- a/app/test-pmd/csumonly.c
>> +++ b/app/test-pmd/csumonly.c
>> @@ -582,7 +582,7 @@ process_outer_cksums(void *outer_l3_hdr, struct
>testpmd_offload_info *info,
>>  		else
>>  			ipv4_hdr->hdr_checksum =
>rte_ipv4_cksum(ipv4_hdr);
>>  	} else
>> -		ol_flags |= RTE_MBUF_F_TX_OUTER_IPV6;
>> +		ol_flags |= RTE_MBUF_F_TX_OUTER_IPV6 |
>RTE_MBUF_F_TX_L4_MASK;
>>
>
>When 'or' with MASK, it is same as requesting UDP checksum.
>```
>#define RTE_MBUF_F_TX_UDP_CKSUM     (3ULL << 52)
>#define RTE_MBUF_F_TX_L4_MASK       (3ULL << 52)
>```
>
>Can you please describe more the problem, is it UDP checksum missing (since
>ipv6 itself doesn't have checksum)?
>If so, shouldn't code check first that if UDP checksum offload is requested?
>Can you please describe why/how above code change is fixing the issue?

Sorry for the late reply!
I re-debugged the issue again and found that it was caused by PMD.
I will resubmit the v2 patch!