Hi, I have an OSPF based network using bird for routing the core and it seems to work fine, however the network is geographically diverse and some of the routing is sub-optimal. Specifically, the default route is going shortest hops rather than lowest latency. What I would like to do is have the OSPF cost reflect the latency of the link, however I am having a problem coming up with a scalable/automated way of doing this. As far as I can tell there is no built in "latency to peer" I can reference? I could configure a manual entry for each peer in the config file, however that doesn't seem very manageable, even with some kind of script to generate the config file.
From what I can gather there is no way for a filter to reference an external file/database/script to adjust the routes on import. I even considered a convoluted approach of having a script inject the peers IP address in to a special kernel table and using the route metric to feed numbers in to bird, but couldn't find a way of storing the data and referencing it on a later route lookup.
Basically what I want is that when an OSPF peer comes up I ping it then set the cost for all routes received from that neighbour to the latency (with some basic sanity like a min and max). I don't expect the latency to vary much once a link is up, however I do need to auto-discover new peers appearing on the network. Any ideas? Thanks - Mike Jones