Porting OSPF route filter rule for BIRD

I have an anycast setup for DNS using BIRD https://unix.stackexchange.com/questions/381962/ospf-migrating-quagga-to-bird However, using "show routes" in the birdc command I see lots of OSPF learned routes from our internal network. As it is, in this anycast setup (and normally), there is only a need to announce routes, and not to receive them. How to create a filter in BIRD to ignore the OSPF routes? My OSPF setup is this one: protocol ospf { tick 2; rfc1583compat yes; area 0.0.0.0 { networks { 1.1.1.0/22; }; stubnet 2.2.2.2/32 { cost 100; }; stubnet 3.3.3.3/32 { cost 500; }; stubnet 4.4.4.4/32 { cost 1000; }; stubnet 5.5.5.5/32 { cost 900; }; interface "eth0" { cost 1000; password "MySecretPassword" { id 5; }; authentication cryptographic; }; interface "dummy0" { stub; }; interface "dummy1" { stub; }; interface "dummy2" { stub; }; interface "dummy3" { stub; }; }; }