> I'm thinking of starting with gated's filtering language,
>
> http://madhaus.utcs.utoronto.ca/gated/config_guide/filter.html
After more thought, Zebra's filtering language might be a better
choice, since it's based on CIDR notation:
http://www.quagga.net/docs/docs-multi/IP-Prefix-List.html
Juliusz