On Mon, Jul 29, 2019 at 2:30 AM Dumitru Ceara <dce...@redhat.com> wrote:
>
> Add a restriction on the target protocol addresses to match the
> configured subnets. All other ARP/ND packets are invalid in this
> context.
>
> One exception is for ARP replies that are received for route next-hops
> that are only reachable via a port but can't be directly resolved
> through route lookups. Such support was introduced by commit:
>
> 6b785fd8fe29 ("ovn-util: Allow /32 IP addresses for router ports.")
>
> Reported-at: https://bugzilla.redhat.com/1729846
> Reported-by: Haidong Li <ha...@redhat.com>
> CC: Han Zhou <zhou...@gmail.com>
> CC: Guru Shetty <g...@ovn.org>
> Fixes: b068454082f5 ("ovn-northd: Support learning neighbor from ARP
request.")
> Signed-off-by: Dumitru Ceara <dce...@redhat.com>Hi Dumitru, Sorry for my slow response, and thanks a lot for revising the patch for a bigger scope of validations. However, the exception of /32 address makes me thinking more about this patch. If ARP replies is allowed from any nexthop for a LR port with /32, at least ARP request for GARP purpose should also be allowed. But before asking for a v3, I'd hold on to rethink the purpose of this patch. The nexthop specific flows are now from static routes. What if OVN support dynamical routing protocols in the future? Of course we can then take those dynamic nexthops into allowed peers. But then I am thinking what is the real benefit of all these restrictions? Why can't we just have simpler logic to handle all these situations without validation? I think the major benefit of the validation is to avoid handling the noise ARP/NDs when multiple subnets shares same L2, but most cases it is really not a big deal, right? For the CPU problem caused by ARP flooding as mentioned by the bug report, it is a real problem, but this patch seems not really helpful for that, because the attacker can just trigger the same CPU problem with *valid* packets. So I am not sure if the benefit of the change is worth the complexity it introduced. Please share your thought and correct me if I missed something. Thanks, Han _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev
