Implementing an "on demand" routing protocol?

Implementing an "on demand" routing protocol?

[Peter Hernberg]

I'm implementing the AODV routing protocol (RFC 3561) on Linux. One of
the protocol's salient features is being "on demand": rather than
receiving (and transmitting) regular updates on the topology of the
network, it waits until it needs a route to a given host (or network).
With AODV routing, in the following simple network

Host A <----> Host B <----> Host C,

it may be that A is unaware of its route to C. If A has a packet
destined for C, it buffers that packet and broadcasts a request for a
route to C.

Is there an interface whereby the kernel can be told "when you have a
packet, but lack a route to its destination, pass a message to this
daemon requesting a route and buffer that packet until the daemon is
done searching for route"? Any info would be appreciated.
-- 
Peter Hernberg

Re: Implementing an "on demand" routing protocol?

[Kevin P. Fleming]

Peter Hernberg wrote:

> Is there an interface whereby the kernel can be told "when you have a
> packet, but lack a route to its destination, pass a message to this
> daemon requesting a route and buffer that packet until the daemon is
> done searching for route"? Any info would be appreciated.

A starting point might be a daemon that listens on a tun interface, with 
that interface being the target of a "default" route. The daemon can 
then receive the packets, do what it likes with them, add routes to the 
routing table, then reinject the packets back into the tun interface 
once the route is in place.