Redistribute Linux kernel/static route metric into OSPF

[bg1729]

I am developing a radio gateway application which presents one tun0 and one tap0 interface to Linux. The application adds static routes to the tun0 interface as endpoint devices connect in over a radio network (currently it uses netlink to do this). I'm using frr / ospfd to re-distribute those routes out on the tap0 interface to a wired network using the redistribute kernel option.

The application understands how good the link to each endpoint is and alternative paths may exist via another gateway instance. I'm looking for a way to reflect this in the OSPF metric / cost for each route added to the tun0 interface. The application currently sets a metric for routes it adds to Linux but I can't find a way of including the Linux static / kernel route metrics in the OSPF cost for a route. Any ideas on how to achieve this (or alternative ideas) would be appreciated.