rt_lookup inside a filter

[Itz Wam]

Hey folks 

Long time user of the software, never sent anything here, today’s my first time

I cannot manage to find anything in the user guide of v1/v2/v3 concerning some sort of rt_lookup inside of filters

The setup is fairly easy
Routers are interconnected heterogeneously, there is a direct BGP session using link local IPv6 on any of these interconnection links

Routers announce loopbacks over these sessions with rr client
There is some sort of local pref / med set up for better traffic quality

Then they all peer with N route reflectors
Sharing the “real” prefixes via loopback addresses

This works well with gateway recursive mode.

There are lot of attributes that we can access inside of filters, what I cannot manage to understand is if it’s possible and how to access let’s say in a filter configured at the RR protocol import/export side - the attributes of the computed gateway - that has been announced on the “underlay” BGP protocol side

For example using external access to bird I can
$ birdc show route all ::/0
::/0 unicast [RR] *
  via 2001:db8::1 on IFACE
  # No BGP.Med

$ birdc show route all 2001:db8::1/128
2001:db8::1/128 unicast [PROTO] *
  via fe80::1 on IFACE
  BGP.med: X
  BGP.local_pref: Y

Hope I didn’t miss some context
Thanks in advance