No vulnerability to MitM attacks via IPv6 rogue router advertisements

[antoninbas]

This issue is here to document that Antrea is not vulnerable to the MitM attacks on IPv4 clusters using IPv6 rogue router advertisements described here: kubernetes/kubernetes#91507

The OVS pipeline defined by Antrea will drop all IPv6 traffic received from containers or the host gateway interface in the SpoofGuard table. This means that no IPv6 traffic will ever be forwarded by the Antrea datapath to other containers or enter the host network namespace.

As we work on IPv6 and dual-stack support (#136), and potentially relax the rules in the SpoofGuard table, we will keep this issue in mind and ensure that Antrea does not become vulnerable to such attacks.

[antoninbas]

Closing issue right away since Antrea is not vulnerable to the attack