317 lines
10 KiB
C
317 lines
10 KiB
C
/*
|
|
* Copyright (c) 2010, Swedish Institute of Computer Science.
|
|
* 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 Institute 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 INSTITUTE 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 INSTITUTE OR CONTRIBUTORS 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.
|
|
*
|
|
* This file is part of the Contiki operating system.
|
|
*
|
|
*/
|
|
|
|
/**
|
|
* \file
|
|
* The Minimum Rank with Hysteresis Objective Function (MRHOF), RFC6719
|
|
*
|
|
* This implementation uses the estimated number of
|
|
* transmissions (ETX) as the additive routing metric,
|
|
* and also provides stubs for the energy metric.
|
|
*
|
|
* \author Joakim Eriksson <joakime@sics.se>, Nicolas Tsiftes <nvt@sics.se>
|
|
*/
|
|
|
|
/**
|
|
* \addtogroup uip
|
|
* @{
|
|
*/
|
|
|
|
#include "net/rpl-classic/rpl.h"
|
|
#include "net/rpl-classic/rpl-private.h"
|
|
#include "net/nbr-table.h"
|
|
#include "net/link-stats.h"
|
|
|
|
#define DEBUG DEBUG_NONE
|
|
#include "net/ipv6/uip-debug.h"
|
|
|
|
/* RFC6551 and RFC6719 do not mandate the use of a specific formula to
|
|
* compute the ETX value. This MRHOF implementation relies on the value
|
|
* computed by the link-stats module. It has an optional feature,
|
|
* RPL_MRHOF_CONF_SQUARED_ETX, that consists in squaring this value.
|
|
* This basically penalizes bad links while preserving the semantics of ETX
|
|
* (1 = perfect link, more = worse link). As a result, MRHOF will favor
|
|
* good links over short paths. Recommended when reliability is a priority.
|
|
* Without this feature, a hop with 50% PRR (ETX=2) is equivalent to two
|
|
* perfect hops with 100% PRR (ETX=1+1=2). With this feature, the former
|
|
* path obtains ETX=2*2=4 and the former ETX=1*1+1*1=2. */
|
|
#ifdef RPL_MRHOF_CONF_SQUARED_ETX
|
|
#define RPL_MRHOF_SQUARED_ETX RPL_MRHOF_CONF_SQUARED_ETX
|
|
#else /* RPL_MRHOF_CONF_SQUARED_ETX */
|
|
#define RPL_MRHOF_SQUARED_ETX 0
|
|
#endif /* RPL_MRHOF_CONF_SQUARED_ETX */
|
|
|
|
#if !RPL_MRHOF_SQUARED_ETX
|
|
/* Configuration parameters of RFC6719. Reject parents that have a higher
|
|
* link metric than the following. The default value is 512 but we use 1024. */
|
|
#define MAX_LINK_METRIC 1024 /* Eq ETX of 8 */
|
|
/* Hysteresis of MRHOF: the rank must differ more than PARENT_SWITCH_THRESHOLD_DIV
|
|
* in order to switch preferred parent. Default in RFC6719: 192, eq ETX of 1.5.
|
|
* We use a more aggressive setting: 96, eq ETX of 0.75.
|
|
*/
|
|
#define PARENT_SWITCH_THRESHOLD 96 /* Eq ETX of 0.75 */
|
|
#else /* !RPL_MRHOF_SQUARED_ETX */
|
|
#define MAX_LINK_METRIC 2048 /* Eq ETX of 4 */
|
|
#define PARENT_SWITCH_THRESHOLD 160 /* Eq ETX of 1.25 (results in a churn comparable
|
|
to the threshold of 96 in the non-squared case) */
|
|
#endif /* !RPL_MRHOF_SQUARED_ETX */
|
|
|
|
/* Reject parents that have a higher path cost than the following. */
|
|
#define MAX_PATH_COST 32768 /* Eq path ETX of 256 */
|
|
|
|
/*---------------------------------------------------------------------------*/
|
|
static void
|
|
reset(rpl_dag_t *dag)
|
|
{
|
|
PRINTF("RPL: Reset MRHOF\n");
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|
|
#if RPL_WITH_DAO_ACK
|
|
static void
|
|
dao_ack_callback(rpl_parent_t *p, int status)
|
|
{
|
|
if(status == RPL_DAO_ACK_UNABLE_TO_ADD_ROUTE_AT_ROOT) {
|
|
return;
|
|
}
|
|
/* here we need to handle failed DAO's and other stuff */
|
|
PRINTF("RPL: MRHOF - DAO ACK received with status: %d\n", status);
|
|
if(status >= RPL_DAO_ACK_UNABLE_TO_ACCEPT) {
|
|
/* punish the ETX as if this was 10 packets lost */
|
|
link_stats_packet_sent(rpl_get_parent_lladdr(p), MAC_TX_OK, 10);
|
|
} else if(status == RPL_DAO_ACK_TIMEOUT) { /* timeout = no ack */
|
|
/* punish the total lack of ACK with a similar punishment */
|
|
link_stats_packet_sent(rpl_get_parent_lladdr(p), MAC_TX_OK, 10);
|
|
}
|
|
}
|
|
#endif /* RPL_WITH_DAO_ACK */
|
|
/*---------------------------------------------------------------------------*/
|
|
static uint16_t
|
|
parent_link_metric(rpl_parent_t *p)
|
|
{
|
|
const struct link_stats *stats = rpl_get_parent_link_stats(p);
|
|
if(stats != NULL) {
|
|
#if RPL_MRHOF_SQUARED_ETX
|
|
uint32_t squared_etx = ((uint32_t)stats->etx * stats->etx) / LINK_STATS_ETX_DIVISOR;
|
|
return (uint16_t)MIN(squared_etx, 0xffff);
|
|
#else /* RPL_MRHOF_SQUARED_ETX */
|
|
return stats->etx;
|
|
#endif /* RPL_MRHOF_SQUARED_ETX */
|
|
}
|
|
return 0xffff;
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|
|
static uint16_t
|
|
parent_path_cost(rpl_parent_t *p)
|
|
{
|
|
uint16_t base;
|
|
|
|
if(p == NULL || p->dag == NULL || p->dag->instance == NULL) {
|
|
return 0xffff;
|
|
}
|
|
|
|
#if RPL_WITH_MC
|
|
/* Handle the different MC types */
|
|
switch(p->dag->instance->mc.type) {
|
|
case RPL_DAG_MC_ETX:
|
|
base = p->mc.obj.etx;
|
|
break;
|
|
case RPL_DAG_MC_ENERGY:
|
|
base = p->mc.obj.energy.energy_est << 8;
|
|
break;
|
|
default:
|
|
base = p->rank;
|
|
break;
|
|
}
|
|
#else /* RPL_WITH_MC */
|
|
base = p->rank;
|
|
#endif /* RPL_WITH_MC */
|
|
|
|
/* path cost upper bound: 0xffff */
|
|
return MIN((uint32_t)base + parent_link_metric(p), 0xffff);
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|
|
static rpl_rank_t
|
|
rank_via_parent(rpl_parent_t *p)
|
|
{
|
|
uint16_t min_hoprankinc;
|
|
uint16_t path_cost;
|
|
|
|
if(p == NULL || p->dag == NULL || p->dag->instance == NULL) {
|
|
return RPL_INFINITE_RANK;
|
|
}
|
|
|
|
min_hoprankinc = p->dag->instance->min_hoprankinc;
|
|
path_cost = parent_path_cost(p);
|
|
|
|
/* Rank lower-bound: parent rank + min_hoprankinc */
|
|
return MAX(MIN((uint32_t)p->rank + min_hoprankinc, 0xffff), path_cost);
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|
|
static int
|
|
parent_is_acceptable(rpl_parent_t *p)
|
|
{
|
|
uint16_t link_metric = parent_link_metric(p);
|
|
uint16_t path_cost = parent_path_cost(p);
|
|
/* Exclude links with too high link metrics or path cost (RFC6719, 3.2.2) */
|
|
return link_metric <= MAX_LINK_METRIC && path_cost <= MAX_PATH_COST;
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|
|
static int
|
|
parent_has_usable_link(rpl_parent_t *p)
|
|
{
|
|
uint16_t link_metric = parent_link_metric(p);
|
|
/* Exclude links with too high link metrics */
|
|
return link_metric <= MAX_LINK_METRIC;
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|
|
static rpl_parent_t *
|
|
best_parent(rpl_parent_t *p1, rpl_parent_t *p2)
|
|
{
|
|
rpl_dag_t *dag;
|
|
uint16_t p1_cost;
|
|
uint16_t p2_cost;
|
|
int p1_is_acceptable;
|
|
int p2_is_acceptable;
|
|
|
|
p1_is_acceptable = p1 != NULL && parent_is_acceptable(p1);
|
|
p2_is_acceptable = p2 != NULL && parent_is_acceptable(p2);
|
|
|
|
if(!p1_is_acceptable) {
|
|
return p2_is_acceptable ? p2 : NULL;
|
|
}
|
|
if(!p2_is_acceptable) {
|
|
return p1_is_acceptable ? p1 : NULL;
|
|
}
|
|
|
|
dag = p1->dag; /* Both parents are in the same DAG. */
|
|
p1_cost = parent_path_cost(p1);
|
|
p2_cost = parent_path_cost(p2);
|
|
|
|
/* Maintain stability of the preferred parent in case of similar ranks. */
|
|
if(p1 == dag->preferred_parent || p2 == dag->preferred_parent) {
|
|
if(p1_cost < p2_cost + PARENT_SWITCH_THRESHOLD &&
|
|
p1_cost > p2_cost - PARENT_SWITCH_THRESHOLD) {
|
|
return dag->preferred_parent;
|
|
}
|
|
}
|
|
|
|
return p1_cost < p2_cost ? p1 : p2;
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|
|
static rpl_dag_t *
|
|
best_dag(rpl_dag_t *d1, rpl_dag_t *d2)
|
|
{
|
|
if(d1->grounded != d2->grounded) {
|
|
return d1->grounded ? d1 : d2;
|
|
}
|
|
|
|
if(d1->preference != d2->preference) {
|
|
return d1->preference > d2->preference ? d1 : d2;
|
|
}
|
|
|
|
return d1->rank < d2->rank ? d1 : d2;
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|
|
#if !RPL_WITH_MC
|
|
static void
|
|
update_metric_container(rpl_instance_t *instance)
|
|
{
|
|
instance->mc.type = RPL_DAG_MC_NONE;
|
|
}
|
|
#else /* RPL_WITH_MC */
|
|
static void
|
|
update_metric_container(rpl_instance_t *instance)
|
|
{
|
|
rpl_dag_t *dag;
|
|
uint16_t path_cost;
|
|
uint8_t type;
|
|
|
|
dag = instance->current_dag;
|
|
if(dag == NULL || !dag->joined) {
|
|
PRINTF("RPL: Cannot update the metric container when not joined\n");
|
|
return;
|
|
}
|
|
|
|
if(dag->rank == ROOT_RANK(instance)) {
|
|
/* Configure MC at root only, other nodes are auto-configured when joining */
|
|
instance->mc.type = RPL_DAG_MC;
|
|
instance->mc.flags = 0;
|
|
instance->mc.aggr = RPL_DAG_MC_AGGR_ADDITIVE;
|
|
instance->mc.prec = 0;
|
|
path_cost = dag->rank;
|
|
} else {
|
|
path_cost = parent_path_cost(dag->preferred_parent);
|
|
}
|
|
|
|
/* Handle the different MC types */
|
|
switch(instance->mc.type) {
|
|
case RPL_DAG_MC_NONE:
|
|
break;
|
|
case RPL_DAG_MC_ETX:
|
|
instance->mc.length = sizeof(instance->mc.obj.etx);
|
|
instance->mc.obj.etx = path_cost;
|
|
break;
|
|
case RPL_DAG_MC_ENERGY:
|
|
instance->mc.length = sizeof(instance->mc.obj.energy);
|
|
if(dag->rank == ROOT_RANK(instance)) {
|
|
type = RPL_DAG_MC_ENERGY_TYPE_MAINS;
|
|
} else {
|
|
type = RPL_DAG_MC_ENERGY_TYPE_BATTERY;
|
|
}
|
|
instance->mc.obj.energy.flags = type << RPL_DAG_MC_ENERGY_TYPE;
|
|
/* Energy_est is only one byte, use the least significant byte of the path metric. */
|
|
instance->mc.obj.energy.energy_est = path_cost >> 8;
|
|
break;
|
|
default:
|
|
PRINTF("RPL: MRHOF, non-supported MC %u\n", instance->mc.type);
|
|
break;
|
|
}
|
|
}
|
|
#endif /* RPL_WITH_MC */
|
|
/*---------------------------------------------------------------------------*/
|
|
rpl_of_t rpl_mrhof = {
|
|
reset,
|
|
#if RPL_WITH_DAO_ACK
|
|
dao_ack_callback,
|
|
#endif
|
|
parent_link_metric,
|
|
parent_has_usable_link,
|
|
parent_path_cost,
|
|
rank_via_parent,
|
|
best_parent,
|
|
best_dag,
|
|
update_metric_container,
|
|
RPL_OCP_MRHOF
|
|
};
|
|
|
|
/** @}*/
|