nes-proj/os/net/routing/rpl-lite/rpl-nbr-policy.c
2018-10-17 11:18:32 +02:00

157 lines
5.3 KiB
C

/*
* 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 rpl-lite
* @{
*
* \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/routing/rpl-lite/rpl.h"
#include "net/nbr-table.h"
/* Log configuration */
#include "sys/log.h"
#define LOG_MODULE "RPL"
#define LOG_LEVEL LOG_LEVEL_RPL
/*
* Policy for neighbor addition
* - one node is locked (default route)
* - max X "best parents"
* => at least MAX_NBRS - (X + 1) free slots for other.
*
* NOTE: this policy assumes that all neighbors end up being IPv6
* neighbors and are not only MAC neighbors.
*/
static int num_parents; /* all nodes that are possible parents */
static int num_free;
static linkaddr_t *worst_rank_nbr_lladdr; /* lladdr of the the neighbor with the worst rank */
static rpl_rank_t worst_rank;
/*---------------------------------------------------------------------------*/
static void
update_state(void)
{
uip_ds6_nbr_t *ds6_nbr;
rpl_nbr_t *rpl_nbr;
rpl_rank_t nbr_rank;
int num_used = 0;
worst_rank = 0;
worst_rank_nbr_lladdr = NULL;
num_parents = 0;
ds6_nbr = nbr_table_head(ds6_neighbors);
while(ds6_nbr != NULL) {
linkaddr_t *nbr_lladdr = nbr_table_get_lladdr(ds6_neighbors, ds6_nbr);
rpl_nbr = rpl_neighbor_get_from_lladdr((uip_lladdr_t *)nbr_lladdr);
if(rpl_nbr != NULL && rpl_neighbor_is_parent(rpl_nbr)) {
num_parents++;
}
nbr_rank = rpl_neighbor_rank_via_nbr(rpl_nbr);
/* Select worst-rank neighbor */
if(rpl_nbr != curr_instance.dag.preferred_parent
&& nbr_rank > worst_rank) {
/* This is the worst-rank neighbor - this is a good candidate for removal */
worst_rank = nbr_rank;
worst_rank_nbr_lladdr = nbr_lladdr;
}
ds6_nbr = nbr_table_next(ds6_neighbors, ds6_nbr);
num_used++;
}
/* how many more IP neighbors can be have? */
num_free = NBR_TABLE_MAX_NEIGHBORS - num_used;
LOG_DBG("nbr-policy: free: %d, parents: %d\n", num_free, num_parents);
}
/*---------------------------------------------------------------------------*/
static const linkaddr_t *
find_worst_rank_nbr_lladdr(void)
{
update_state();
return worst_rank_nbr_lladdr;
}
/*---------------------------------------------------------------------------*/
static const linkaddr_t *
find_removable_dio(uip_ipaddr_t *from, rpl_dio_t *dio)
{
update_state();
if(!curr_instance.used || curr_instance.instance_id != dio->instance_id) {
LOG_WARN("nbr-policy: did not find instance id: %d\n", dio->instance_id);
return NULL;
}
/* Add the new neighbor only if it is better than the current worst. */
if(dio->rank + curr_instance.min_hoprankinc < worst_rank - curr_instance.min_hoprankinc / 2) {
/* Found *great* neighbor - add! */
LOG_DBG("nbr-policy: DIO rank %u, worst_rank %u -- add to cache\n",
dio->rank, worst_rank);
return worst_rank_nbr_lladdr;
}
LOG_DBG("nbr-policy: DIO rank %u, worst_rank %u -- do not add to cache\n",
dio->rank, worst_rank);
return NULL;
}
/*---------------------------------------------------------------------------*/
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_DIS:
return find_worst_rank_nbr_lladdr();
case NBR_TABLE_REASON_IPV6_ND_AUTOFILL:
return find_worst_rank_nbr_lladdr();
default:
return NULL;
}
}
/*---------------------------------------------------------------------------*/
/** @}*/