Re: [dpdk-dev] ixgbe and UDP with zero checksum

[Paolo Valerio <pvalerio@redhat.com>]

"Wang, Haiyue" <haiyue.wang@intel.com> writes:

> Hi Paolo,
>
>> -----Original Message-----
>> From: Paolo Valerio <pvalerio@redhat.com>
>> Sent: Wednesday, January 27, 2021 21:50
>> To: dev@dpdk.org
>> Cc: Guo, Jia <jia.guo@intel.com>; Wang, Haiyue <haiyue.wang@intel.com>; Aaron Conole
>> <aconole@redhat.com>
>> Subject: ixgbe and UDP with zero checksum
>> 
>> Hi,
>> 
>> performing some tests, I noticed that on ixgbe when receiving UDP
>> packets with zero checksum (no checksum) over IPv4, the corresponding
>> ol_flag for the l4 checksum is set to PKT_RX_L4_CKSUM_BAD.
>> 
>> In particular, this apparently has an impact on OvS using ct() action
>> where UDP packets with zero checksum are not tracked because of that.
>
>
>> 
>> [1]
>> https://patchwork.ozlabs.org/project/netdev/patch/20090724040031.30202.1531.stgit@localhost.localdomai
>> n/
>
> About 12 years old patch, it is hardware errata. For fixing this,
> have to always disable vector Rx path for 82599, it seems not a
> good idea to bring in this workaround. :(
>

Thanks for the answer.
Yes, as I mentioned, the patch is old although still meaningful.
I linked it mostly because it mentions the hw errata.

I would refer to Aaron's questions because they bring up the point.

> +		/*
> +		 * 82599 errata, UDP frames with a 0 checksum can be marked as
> +		 * checksum errors.
> +		 */
> +		if ((pkt_info & IXGBE_RXDADV_PKTTYPE_UDP) &&
> +		    (adapter->hw.mac.type == ixgbe_mac_82599EB))
> +			return;
>
>> 
>> Regards,
>> Paolo