[OVN] Metadata namespace checksum error with DPDK

[Rodolfo Alonso]

When using OVS+DPDK, the veth pair between the metadata namespace and OVS do not process the checksum. See [1][2].

Because the metadata namespace only process the TCP traffic from the VM to request the metadata info, the proposed solution could be to, using netfilter, add the checksum to those packets. E.g.:

$ sudo ip net e ovnmeta-32aa0742-f6ae-4b15-a66d-9516b1a3121a iptables -A POSTROUTING -t mangle -p tcp -m tcp -j CHECKSUM --checksum-fill

This rule will add the correct checksum to the TCP packets in this namespace.

[1]https://bugs.launchpad.net/neutron/+bug/1832021
[2]https://bugs.launchpad.net/charm-neutron-openvswitch/+bug/1831935

[Slawek Kaplonski (slaweq)]

Fixed by https://review.opendev.org/c/openstack/neutron/+/763745 and https://review.opendev.org/c/openstack/neutron/+/772286
And also related patch https://review.opendev.org/c/openstack/neutron/+/778395

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 16.3.1 release.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 17.1.1 release.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 18.0.0.0rc1 release candidate.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/networking-ovn 7.4.1 release.