Hi Roberto:

Please open a launchpad bug documenting this issue in os-ken.

Thanks!

On Wed, Nov 16, 2022 at 3:41 PM Roberto Bartzen Acosta <roberto.acosta@luizalabs.com> wrote:
Thanks Sean.

 I believe that the os-ken driver is not coded to honor this premise because the below function can learn new paths from peer update messages.
https://opendev.org/openstack/os-ken/src/branch/master/os_ken/services/protocols/bgp/peer.py#L1544

Em qua., 16 de nov. de 2022 às 09:14, Sean Mooney <smooney@redhat.com> escreveu:
On Wed, 2022-11-16 at 09:05 -0300, Roberto Bartzen Acosta wrote:
> Sorry for the mistake, I meant, the bgpspeaker should only "*advertise*!"
> and not "learn" the AS_PATHs via BGP.
yes that used to be the scope of that project to advertise only and not learn
so i would geuss either that has change recently and they broke backward compaitbly
or they have refactord it to use an external bgp speaker like frr and it learns by default

i dont really see anything here https://github.com/openstack/neutron-dynamic-routing/commits/master
im not really familar with the internals of the project but i dont see any code to learn routs form

https://github.com/openstack/neutron-dynamic-routing/blob/master/neutron_dynamic_routing/services/bgp/agent/driver/os_ken/driver.py

it just has code for advertizing and withdrawing routes.



>
> Em qua., 16 de nov. de 2022 às 08:57, Sean Mooney <smooney@redhat.com>
> escreveu:
>
> > On Wed, 2022-11-16 at 08:43 -0300, Roberto Bartzen Acosta wrote:
> > > Hey folks,
> > >
> > > Please, I have a question here, the bgpspeaker should only "learn" and
> > not
> > > "advertise" the AS_PATHs via BGP, right?
> >
> > its been a while since i looked at it but in the past it did not supprot
> > learning at all
> >
> > it just advertised the routes for the neutron netowrks
> >
> > >
> > > In my tests, I can see that it is learning routes from BGP neighbors.
> > This
> > > behavior can cause an AS_PATH loop because the bgpspeaker learns back its
> > > own advertised routes, and I see a message like this in the logs:
> > >
> > > 2022-11-11 19:45:41.967 7220 ERROR bgpspeaker.peer [-] AS_PATH on UPDATE
> > > message has loops. Ignoring this message:
> > >
> > BGPUpdate(len=91,nlri=[],path_attributes=[BGPPathAttributeMpReachNLRI(afi=2,flags=144,length=46,next_hop='2001:db7:1::1',nlri=[IP6AddrPrefix(addr='2001:db9:1234::',length=64)],safi=1,type=14),
> > > BGPPathAttributeOrigin(flags=64,length=1,type=1,value=0),
> > > BGPPathAttributeAsPath(flags=80,length=10,type=2,value=[[65001,
> > >
> > 65000]])],total_path_attribute_len=68,type=2,withdrawn_routes=[],withdrawn_routes_len=0)
> > >
> > > This can be fixed by suppressing the neighbor route advertisement (using
> > > route-map export), but have I misunderstood how neutron-dymanic-routing
> > > works or do we have a possible bug here?
> > >
> > > Regards
> > >
> >
> >
>



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