two AS announce config migration 1.6.6 -> 2.0.12

[Ondrej Zajicek]

On Thu, Jul 27, 2023 at 04:39:23AM +0300, nixx wrote:
>  show route for 192.168.200.100
> and
> show route protocol TestMain all
> in attachments.
>
> Has something changed in the work process of the bird, or am I doing
> something wrong?

Yes, it seems that there is a minor change in interpretation of 'next hop keep' option.

In v1.6 it affected both originating and forwarding of the bgp_next_hop attribute,
while in v2.0 it affects just forwarding of an existing attribute (as during
originating, there is no bgp_next_hop to keep).

Therefore TestPeer when originating these routes is used its IP address as
bgp_next_hop, it used its IP address as bgp_next_hop, as it is expected for
EBGP peer when the original route has gw on different iface.

Simple workaround is to set bgp_next_hop manually in TestPeer export filter,
e.g.: bgp_next_hop = gw;


Also note that in v2, you could simplify the setup by removing TestPeer
and just adding ASN 65065 to bgp_path either in static protocol import
filter, or in TestMain export filter: bgp_path.prepend(65065);

This would not work in v1.6, as there was a different order of processing
export filter and internal BGP attribute processing.

-- 
Elen sila lumenn' omentielvo

Ondrej 'Santiago' Zajicek (email: santiago at crfreenet.org)
OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net)
"To err is human -- to blame it on a computer is even more so."