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

Hi Paolo,

-----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.

[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. :(

+		/*
+		 * 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