On Thu, Aug 8, 2024 at 5:26 PM Numan Siddique <[email protected]> wrote:
>
> On Thu, Aug 8, 2024 at 5:22 PM Numan Siddique <[email protected]> wrote:
> >
> > On Thu, Aug 8, 2024 at 3:17 PM Dumitru Ceara <[email protected]> wrote:
> > >
> > > On 8/8/24 20:00, Ilya Maximets wrote:
> > > > MLD flows are added to pipelines unconditionally in order to avoid
> > > > sending such traffic through conntrack.  The problem is that these
> > > > matches turn into matches on ip6.dst that end up as exact matches in
> > > > datapath flows.  This means a separate datapath flow per destination
> > > > IP address.  This may cause significant performance issues in setups
> > > > where traffic for many different IP addresses is passing through.
> > > > Since network protocol is stored further in the packet, it is evaluated
> > > > after checking the IP addresses, and so having a match on ip.proto
> > > > doesn't save us in this scenario.
> > > >
> > > > MLD packets are all supposed to be multicast packets and so they all
> > > > should have multicast destination ethernet addresses.  Add the missing
> > > > eth.mcast6 match to all such packets.  This ensures that non-multicast
> > > > traffic will quickly fail the OpenFlow lookup on such rules and the bits
> > > > from higher layers will not be added to the match criteria in datapath
> > > > flows.  This also ensures that OVN doesn't handle incorrect MLD packets.
> > > >
> > > > There are still ND responder flows that can add extra matches for IPv6
> > > > addresses, but they can be disabled or handled by other means.
> > > >
> > > > IGMP did not check for IP address being multicast for some reason, so
> > > > it didn't cause issues for IPv4 traffic.  But let's fix it as well.
> > > >
> > > > Tests were using incorrect multicast addresses, fixed now.
> > > >
> > > > Fixes: 677a3ba4d66b ("ovn: Add MLD support.")
> > > > Signed-off-by: Ilya Maximets <[email protected]>
> > > > ---
> > >
> > > Thanks for the fix, Ilya!  Looks good to me.
> > >
> > > Acked-by: Dumitru Ceara <[email protected]>
> >
> > Thanks for the fix.  I applied this patch to the main.  I'll backport
> > to other branches after running the tests in my github CI.
>
> Regarding the matches for the ND responder flows, we already support an option
> to disable arp/nd responder flows [1].  The user can use this option for now.
> But I think we should address the datapath flow explosion due to these
> ND responder flows (if the user doesn't
> want to disable these flows).
>
> [1] - 
> https://github.com/ovn-org/ovn/commit/72fac9b51a5f5690ca37e83ead582aee3f94399e

I forgot to mention one thing.  I added Reported-at and Reported-by
tags before applying the patch.

The backport is not cleanly applying for the branch-23.09.  @Ilya
Maximets  Can you please take a look at it
and submit branch-23.09 only patch ?

Thanks
Numan

>
>
> Numan
>
> >
> > Numan
> >
> > >
> > > Regards,
> > > Dumitru
> > >
> > > _______________________________________________
> > > dev mailing list
> > > [email protected]
> > > https://mail.openvswitch.org/mailman/listinfo/ovs-dev
> > >
_______________________________________________
dev mailing list
[email protected]
https://mail.openvswitch.org/mailman/listinfo/ovs-dev

Reply via email to