256 lines
8.3 KiB
C
256 lines
8.3 KiB
C
/*
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* Copyright (c) 2014-2015, Yanzi Networks AB.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the copyright holders nor the
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* names of its contributors may be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT HOLDERS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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*/
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/**
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* \addtogroup uip6
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* @{
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*/
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/**
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* \file
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*
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* Default RPL NBR policy
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* decides when to add a new discovered node to the nbr table from RPL.
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*
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* \author Joakim Eriksson <joakime@sics.se>
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* Contributors: Niclas Finne <nfi@sics.se>, Oriol Piñol <oriol@yanzi.se>,
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*
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*/
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#include "net/rpl/rpl-private.h"
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#include "net/nbr-table.h"
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#include "net/ipv6/uip-ds6-nbr.h"
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#include "net/ipv6/uip-ds6-route.h"
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#define DEBUG DEBUG_NONE
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#include "net/ip/uip-debug.h"
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/*
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* Policy for neighbor adds
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* - one node is locked (default route)
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* - max X children (nexthops)
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* - max Y "best parents"
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* => at least MAX_NBRS - (Y + X + 1) free slots for other.
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*
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* NOTE: this policy assumes that all neighbors end up being IPv6
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* neighbors and are not only MAC neighbors.
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*/
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#define MAX_CHILDREN (NBR_TABLE_MAX_NEIGHBORS - 2)
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#define UIP_IP_BUF ((struct uip_ip_hdr *)&uip_buf[UIP_LLH_LEN])
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static int num_parents; /* any node that are possible parents */
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static int num_children; /* all children that we have as nexthop */
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static int num_free;
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static linkaddr_t *worst_rank_nbr; /* the parent that has the worst rank */
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static rpl_rank_t worst_rank;
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/*---------------------------------------------------------------------------*/
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#if DEBUG == DEBUG_FULL
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/*
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* This create a periodic call of the update_nbr function that will print
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* useful debugging information when in DEBUG_FULL mode
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*/
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static void update_nbr(void);
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static struct ctimer periodic_timer;
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static int timer_init = 0;
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static void
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handle_periodic_timer(void *ptr)
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{
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update_nbr();
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ctimer_restart(&periodic_timer);
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}
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#endif /* DEBUG == DEBUG_FULL */
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/*---------------------------------------------------------------------------*/
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static void
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update_nbr(void)
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{
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uip_ds6_nbr_t *nbr;
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rpl_parent_t *parent;
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int num_used;
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int is_used;
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rpl_rank_t rank;
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#if DEBUG == DEBUG_FULL
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if(!timer_init) {
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timer_init = 1;
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ctimer_set(&periodic_timer, 60 * CLOCK_SECOND,
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&handle_periodic_timer, NULL);
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}
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#endif /* DEBUG == DEBUG_FULL */
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worst_rank = 0;
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worst_rank_nbr = NULL;
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num_used = 0;
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num_parents = 0;
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num_children = 0;
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nbr = nbr_table_head(ds6_neighbors);
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while(nbr != NULL) {
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linkaddr_t *lladdr = nbr_table_get_lladdr(ds6_neighbors, nbr);
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is_used = 0;
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/*
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* Check if this neighbor is used as nexthop and therefor being a
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* RPL child.
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*/
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if(uip_ds6_route_is_nexthop(&nbr->ipaddr) != 0) {
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is_used++;
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num_children++;
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}
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parent = rpl_get_parent((uip_lladdr_t *)lladdr);
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if(parent != NULL) {
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num_parents++;
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if(parent->dag != NULL && parent->dag->preferred_parent == parent) {
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/*
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* This is the preferred parent for the DAG and must not be removed
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* Note: this assumes that only RPL adds default routes.
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*/
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} else if(is_used == 0 && worst_rank < INFINITE_RANK &&
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parent->rank > 0 &&
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parent->dag != NULL &&
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parent->dag->instance != NULL &&
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(rank = parent->dag->instance->of->rank_via_parent(parent)) > worst_rank) {
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/* This is the worst-rank neighbor - this is a good candidate for removal */
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worst_rank = rank;
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worst_rank_nbr = lladdr;
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}
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/* add to is_used after evaluation of is_used above */
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is_used++;
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}
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if(is_used == 0) {
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/* This neighbor is neither parent or child and can be safely removed */
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worst_rank_nbr = lladdr;
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worst_rank = INFINITE_RANK;
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} else if(is_used > 1) {
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PRINTF("NBR-POLICY: *** Neighbor is both child and candidate parent: ");
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PRINTLLADDR((uip_lladdr_t *)lladdr);
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PRINTF("\n");
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}
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nbr = nbr_table_next(ds6_neighbors, nbr);
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num_used++;
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}
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/* how many more IP neighbors can be have? */
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num_free = NBR_TABLE_MAX_NEIGHBORS - num_used;
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PRINTF("NBR-POLICY: Free: %d, Children: %d, Parents: %d Routes: %d\n",
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num_free, num_children, num_parents, uip_ds6_route_num_routes());
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}
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/*---------------------------------------------------------------------------*/
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/* Called whenever we get a unicast DIS - e.g. someone that already
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have this node in its table - since it is a unicast */
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const linkaddr_t *
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find_removable_dis(uip_ipaddr_t *from)
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{
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update_nbr();
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if(num_free > 0) {
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/* there are free entries (e.g. unsused by RPL and ND6) but since it is
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used by other modules we can not pick these entries for removal. */
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PRINTF("NBR-POLICY: Num-free > 0 = %d - Other for RPL/ND6 unused NBR entry exists .",
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num_free);
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}
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if(num_children < MAX_CHILDREN) {
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return worst_rank_nbr;
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}
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return NULL;
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}
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/*---------------------------------------------------------------------------*/
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const linkaddr_t *
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find_removable_dio(uip_ipaddr_t *from, rpl_dio_t *dio)
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{
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rpl_instance_t *instance;
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update_nbr();
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instance = rpl_get_instance(dio->instance_id);
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if(instance == NULL || instance->current_dag == NULL) {
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PRINTF("NBR-POLICY: Did not find instance id: %d\n", dio->instance_id);
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return NULL;
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}
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/* Add the new neighbor only if it is better than the worst parent. */
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if(dio->rank + instance->min_hoprankinc < worst_rank - instance->min_hoprankinc / 2) {
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/* Found *great* neighbor - add! */
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PRINTF("NBR-POLICY: Found better neighbor %d < %d - add to cache...\n",
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dio->rank, worst_rank);
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return worst_rank_nbr;
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}
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PRINTF("NBR-POLICY: Found worse neighbor with new %d and old %d - NOT add to cache.\n",
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dio->rank, worst_rank);
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return NULL;
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}
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/*---------------------------------------------------------------------------*/
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const linkaddr_t *
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find_removable_dao(uip_ipaddr_t *from, rpl_instance_t *instance)
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{
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int max = MAX_CHILDREN;
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update_nbr();
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if(instance != NULL) {
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/* No need to reserve space for parents for RPL ROOT */
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if(instance->current_dag->rank == ROOT_RANK(instance)) {
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max = NBR_TABLE_MAX_NEIGHBORS;
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}
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}
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/* Check if this DAO sender is not yet neighbor and there is already too
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many children. */
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if(num_children >= max) {
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PRINTF("NBR-POLICY: Can not add another child - already at max.\n");
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return NULL;
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}
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/* remove the worst ranked nbr */
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return worst_rank_nbr;
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}
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/*---------------------------------------------------------------------------*/
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const linkaddr_t *
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rpl_nbr_policy_find_removable(nbr_table_reason_t reason,void * data)
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{
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/* When we get the DIO/DAO/DIS we know that UIP contains the
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incoming packet */
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switch(reason) {
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case NBR_TABLE_REASON_RPL_DIO:
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return find_removable_dio(&UIP_IP_BUF->srcipaddr, data);
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case NBR_TABLE_REASON_RPL_DAO:
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return find_removable_dao(&UIP_IP_BUF->srcipaddr, data);
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case NBR_TABLE_REASON_RPL_DIS:
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return find_removable_dis(&UIP_IP_BUF->srcipaddr);
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default:
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return NULL;
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}
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}
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/*---------------------------------------------------------------------------*/
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/** @}*/
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