How to get all the preferred parents up to the root for a certain node in Contiki RPL classic?

Question

I'm using Contiki 3.0 and I would like to find all the preferred parents up to the root for a certain node. For Example, if I have node 1 with preferred parent node 5, node 5 with preferred parent node 8 and node 8 connected directly to the root. How can I find or print these preferred parents like this: 1-> 5 -> 8 -> root.
I'm using this code to get the preferred parent: PRINT6ADDR(rpl_get_parent_ipaddr(dag->preferred_parent));

Many Thanks Hanin

Answer 1

You cannot print this information on a node since RPL is a distance vector protocol, not a link state protocol. A network node does not have enough information to know the full routing path to the root node; it has just a local view of the network, limited to their immediate neighbors.