open a file at location
->Home/user/contiki/core/
net/rpl/ipv6/uip-ds6-nbr.c
handle the neighbor address in rpl.

uip_ds6_nbr_add(const uip_ipaddr_t *ipaddr, const uip_lladdr_t *lladdr, uint8_t isrouter, uint8_t state, int recvcount) {

// each node neighbor address maintained

}

for(nbr1= nbr_table_head(ds6_neighbors); nbr1 != NULL; nbr1 = nbr_table_next(ds6_neighbors, nbr1)) {

neighborcount++;

nbr_id1 = &nbr1->ipaddr;

Recvcount = nbr1->nb_recvc; // received Count Accessed from neighbor address

}