My question is about some kind of policy routing (setup by the administrator, not guessed by batman).
Consider the following topology:
l0 l1 A ---- B ==== C l2
where --- is a single link (l0) and === are two links (l1 and l2).
Now imagine that the administator wants to dedicate the link l2 to the communication between B and C, for whatever reason. It is fairly easy to set netfilter rules to that effect, for instance.
Hi Gabriel
Remember that BATMAN is a Layer 2 mesh, not layer 3.
It would be possible to do what you want. Simply don't add the l2 interfaces to BATMAN, put IP addresses from a different subnet on the interfaces, and B and C can use the link l2 for themselves, and use the bat0 interface for access to the mesh subnet.
Andrew