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

-----Original Message-----
From: Paolo Valerio <redacted>
Sent: Thursday, January 28, 2021 05:35
To: Wang, Haiyue <redacted>
Cc: Guo, Jia <redacted>; Aaron Conole <aconole@redhat.com>; dev@dpdk.org
Subject: RE: ixgbe and UDP with zero checksum

"Wang, Haiyue" [off-list ref] writes:

quoted

Hi Paolo,

quoted

-----Original Message-----
From: Paolo Valerio <redacted>
Sent: Wednesday, January 27, 2021 21:50
To: dev@dpdk.org
Cc: Guo, Jia <redacted>; Wang, Haiyue <redacted>; Aaron Conole
[off-list ref]
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.

quoted

[1]

https://patchwork.ozlabs.org/project/netdev/patch/20090724040031.30202.1531.stgit@localhost.localdomai

quoted

quoted

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.

What's your PCI device ID ? My worked ixgbe:

86:00.0 Ethernet controller [0200]: Intel Corporation 82599ES 10-Gigabit SFI/SFP+ Network Connection [8086:10fb] (rev 01)

I'm wondering if people will complain that the patch will mark the real bad checksum UDP as
GOOD. For handling this correctly, looks like driver needs to check the UDP's checksum value,
if zero, then skip the error information, but this makes driver do the network stack things ...