Hi,

Former RPL was a port of contiki's RPL implementation, if I am not
mistaken. But it slipped a lot compared to its original code, which one
got a lot more features implemented.

Also, the issue with it, was that it was not very well following our
common design scheme in the network stack, since that was a code from
another OS. It was quite messy, and not optimized as well (a lot of
timers everywher, the context data for RPL was way too big). I'd advise
to reimplement RPL support from scratch. It should be simpler as well
now that net_pkt got its API reworked. Following the design in
ipv6_nbr.c would be a good example I guess.

Br,

Tomasz