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