To remove the DAG path in RPL routing process. Once the current dag of node removed from the routing, it will not participate further routing process.
Open a file Location -->contiki/core/net/rpl/rpl-dag.c
Handle the function , rpl_dag_t * rpl_set_root(uint8_t instance_id, uip_ipaddr_t *dag_id)
Condition:
if(instance->current_dag != dag && instance->current_dag != NULL) {
/* Remove routes installed by DAOs. */
rpl_remove_routes(instance->current_dag);
instance->current_dag->joined = 0;
}
When the node satisfies this condition, that will not participate the routing.