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contiki/core/net/rpl/rpl-dag.c

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/**
* \addtogroup uip6
* @{
*/
/*
* 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
* Logic for Directed Acyclic Graphs in RPL.
*
* \author Joakim Eriksson <joakime@sics.se>, Nicolas Tsiftes <nvt@sics.se>
*/
#include "contiki.h"
#include "net/rpl/rpl-private.h"
#include "net/uip.h"
#include "net/uip-nd6.h"
#include "lib/list.h"
#include "lib/memb.h"
#include "sys/ctimer.h"
#include <limits.h>
#include <string.h>
#define DEBUG DEBUG_NONE
#include "net/uip-debug.h"
#include "net/neighbor-info.h"
/*---------------------------------------------------------------------------*/
extern rpl_of_t RPL_OF;
static rpl_of_t * const objective_functions[] = {&RPL_OF};
/*---------------------------------------------------------------------------*/
#ifndef RPL_CONF_MAX_PARENTS_PER_DAG
#define RPL_MAX_PARENTS_PER_DAG 8
#else
#define RPL_MAX_PARENTS_PER_DAG RPL_CONF_MAX_PARENTS_PER_DAG
#endif /* !RPL_CONF_MAX_PARENTS_PER_DAG */
/*---------------------------------------------------------------------------*/
/* RPL definitions. */
#ifndef RPL_CONF_GROUNDED
#define RPL_GROUNDED 0
#else
#define RPL_GROUNDED RPL_CONF_GROUNDED
#endif /* !RPL_CONF_GROUNDED */
/*---------------------------------------------------------------------------*/
/* Allocate parents from the same static MEMB chunk to reduce memory waste. */
MEMB(parent_memb, struct rpl_parent,
RPL_MAX_PARENTS_PER_DAG * RPL_MAX_INSTANCES * RPL_MAX_DAG_PER_INSTANCE);
/*---------------------------------------------------------------------------*/
/* Allocate instance table. */
rpl_instance_t instance_table[RPL_MAX_INSTANCES];
rpl_instance_t *default_instance;
/*---------------------------------------------------------------------------*/
/* Greater-than function for the lollipop counter. */
/*---------------------------------------------------------------------------*/
static int
lollipop_greater_than(int a, int b)
{
/* Check if we are comparing an initial value with an old value */
if(a > RPL_LOLLIPOP_CIRCULAR_REGION && b <= RPL_LOLLIPOP_CIRCULAR_REGION) {
return (RPL_LOLLIPOP_MAX_VALUE + 1 + b - a) > RPL_LOLLIPOP_SEQUENCE_WINDOWS;
}
/* Otherwise check if a > b and comparable => ok, or
if they have wrapped and are still comparable */
return (a > b && (a - b) < RPL_LOLLIPOP_SEQUENCE_WINDOWS) ||
(a < b && (b - a) > (RPL_LOLLIPOP_CIRCULAR_REGION + 1-
RPL_LOLLIPOP_SEQUENCE_WINDOWS));
}
/*---------------------------------------------------------------------------*/
/* Remove DAG parents with a rank that is at least the same as minimum_rank. */
static void
remove_parents(rpl_dag_t *dag, rpl_rank_t minimum_rank)
{
rpl_parent_t *p, *p2;
PRINTF("RPL: Removing parents (minimum rank %u)\n",
minimum_rank);
for(p = list_head(dag->parents); p != NULL; p = p2) {
p2 = p->next;
if(p->rank >= minimum_rank) {
rpl_remove_parent(dag, p);
}
}
}
/*---------------------------------------------------------------------------*/
static void
nullify_parents(rpl_dag_t *dag, rpl_rank_t minimum_rank)
{
rpl_parent_t *p, *p2;
PRINTF("RPL: Removing parents (minimum rank %u)\n",
minimum_rank);
for(p = list_head(dag->parents); p != NULL; p = p2) {
p2 = p->next;
if(p->rank >= minimum_rank) {
rpl_nullify_parent(dag, p);
}
}
}
/*---------------------------------------------------------------------------*/
static void
remove_worst_parent(rpl_dag_t *dag, rpl_rank_t min_worst_rank)
{
rpl_parent_t *p, *worst;
PRINTF("RPL: Removing the worst parent\n");
/* Find the parent with the highest rank. */
worst = NULL;
for(p = list_head(dag->parents); p != NULL; p = list_item_next(p)) {
if(p != dag->preferred_parent &&
(worst == NULL || p->rank > worst->rank)) {
worst = p;
}
}
/* Remove the neighbor if its rank is worse than the minimum worst rank. */
if(worst != NULL && worst->rank > min_worst_rank) {
rpl_remove_parent(dag, worst);
}
}
/*---------------------------------------------------------------------------*/
static int
should_send_dao(rpl_instance_t *instance, rpl_dio_t *dio, rpl_parent_t *p)
{
/* if MOP is set to no downward routes no DAO should be sent */
if(instance->mop == RPL_MOP_NO_DOWNWARD_ROUTES) {
return 0;
}
/* check if the new DTSN is more recent */
return p == instance->current_dag->preferred_parent &&
(lollipop_greater_than(dio->dtsn, p->dtsn));
}
/*---------------------------------------------------------------------------*/
static int
acceptable_rank(rpl_dag_t *dag, rpl_rank_t rank)
{
return rank != INFINITE_RANK &&
((dag->instance->max_rankinc == 0) ||
DAG_RANK(rank, dag->instance) <= DAG_RANK(dag->min_rank + dag->instance->max_rankinc, dag->instance));
}
/*---------------------------------------------------------------------------*/
static rpl_dag_t *
get_dag(uint8_t instance_id, uip_ipaddr_t *dag_id)
{
rpl_instance_t *instance;
rpl_dag_t *dag;
int i;
instance = rpl_get_instance(instance_id);
if(instance == NULL) {
return NULL;
}
for(i = 0; i < RPL_MAX_DAG_PER_INSTANCE; ++i) {
dag = &instance->dag_table[i];
if(dag->used && uip_ipaddr_cmp(&dag->dag_id, dag_id)) {
return dag;
}
}
return NULL;
}
/*---------------------------------------------------------------------------*/
rpl_dag_t *
rpl_set_root(uint8_t instance_id, uip_ipaddr_t *dag_id)
{
rpl_dag_t *dag;
rpl_instance_t *instance;
uint8_t version;
version = RPL_LOLLIPOP_INIT;
dag = get_dag(instance_id, dag_id);
if(dag != NULL) {
version = dag->version;
RPL_LOLLIPOP_INCREMENT(version);
PRINTF("RPL: Dropping a joined DAG when setting this node as root");
if(dag == dag->instance->current_dag) {
dag->instance->current_dag = NULL;
}
rpl_free_dag(dag);
}
dag = rpl_alloc_dag(instance_id, dag_id);
if(dag == NULL) {
PRINTF("RPL: Failed to allocate a DAG\n");
return NULL;
}
instance = dag->instance;
dag->version = version;
dag->joined = 1;
dag->grounded = RPL_GROUNDED;
instance->mop = RPL_MOP_DEFAULT;
instance->of = &RPL_OF;
dag->preferred_parent = NULL;
memcpy(&dag->dag_id, dag_id, sizeof(dag->dag_id));
instance->dio_intdoubl = RPL_DIO_INTERVAL_DOUBLINGS;
instance->dio_intmin = RPL_DIO_INTERVAL_MIN;
/* The current interval must differ from the minimum interval in order to
trigger a DIO timer reset. */
instance->dio_intcurrent = RPL_DIO_INTERVAL_MIN +
RPL_DIO_INTERVAL_DOUBLINGS;
instance->dio_redundancy = RPL_DIO_REDUNDANCY;
instance->max_rankinc = RPL_MAX_RANKINC;
instance->min_hoprankinc = RPL_MIN_HOPRANKINC;
instance->default_lifetime = RPL_DEFAULT_LIFETIME;
instance->lifetime_unit = RPL_DEFAULT_LIFETIME_UNIT;
dag->rank = ROOT_RANK(instance);
if(instance->current_dag != dag && instance->current_dag != NULL) {
/* Remove routes installed by DAOs. */
rpl_remove_routes(instance->current_dag);
instance->current_dag->joined = 0;
}
instance->current_dag = dag;
instance->dtsn_out = RPL_LOLLIPOP_INIT;
instance->of->update_metric_container(instance);
default_instance = instance;
PRINTF("RPL: Node set to be a DAG root with DAG ID ");
PRINT6ADDR(&dag->dag_id);
PRINTF("\n");
ANNOTATE("#A root=%u\n", dag->dag_id.u8[sizeof(dag->dag_id) - 1]);
rpl_reset_dio_timer(instance);
return dag;
}
/*---------------------------------------------------------------------------*/
int
rpl_repair_root(uint8_t instance_id)
{
rpl_instance_t *instance;
instance = rpl_get_instance(instance_id);
if(instance == NULL ||
instance->current_dag->rank != ROOT_RANK(instance)) {
return 0;
}
RPL_LOLLIPOP_INCREMENT(instance->current_dag->version);
RPL_LOLLIPOP_INCREMENT(instance->dtsn_out);
rpl_reset_dio_timer(instance);
return 1;
}
/*---------------------------------------------------------------------------*/
static void
set_ip_from_prefix(uip_ipaddr_t *ipaddr, rpl_prefix_t *prefix)
{
memset(ipaddr, 0, sizeof(uip_ipaddr_t));
memcpy(ipaddr, &prefix->prefix, (prefix->length + 7) / 8);
uip_ds6_set_addr_iid(ipaddr, &uip_lladdr);
}
/*---------------------------------------------------------------------------*/
static void
check_prefix(rpl_prefix_t *last_prefix, rpl_prefix_t *new_prefix)
{
uip_ipaddr_t ipaddr;
uip_ds6_addr_t *rep;
if(last_prefix != NULL && new_prefix != NULL &&
last_prefix->length == new_prefix->length &&
uip_ipaddr_prefixcmp(&last_prefix->prefix, &new_prefix->prefix, new_prefix->length) &&
last_prefix->flags == new_prefix->flags) {
/* Nothing has changed. */
return;
}
if(last_prefix != NULL) {
set_ip_from_prefix(&ipaddr, last_prefix);
rep = uip_ds6_addr_lookup(&ipaddr);
if(rep != NULL) {
PRINTF("RPL: removing global IP address ");
PRINT6ADDR(&ipaddr);
PRINTF("\n");
uip_ds6_addr_rm(rep);
}
}
if(new_prefix != NULL) {
set_ip_from_prefix(&ipaddr, new_prefix);
if(uip_ds6_addr_lookup(&ipaddr) == NULL) {
PRINTF("RPL: adding global IP address ");
PRINT6ADDR(&ipaddr);
PRINTF("\n");
uip_ds6_addr_add(&ipaddr, 0, ADDR_AUTOCONF);
}
}
}
/*---------------------------------------------------------------------------*/
int
rpl_set_prefix(rpl_dag_t *dag, uip_ipaddr_t *prefix, unsigned len)
{
if(len > 128) {
return 0;
}
memset(&dag->prefix_info.prefix, 0, sizeof(dag->prefix_info.prefix));
memcpy(&dag->prefix_info.prefix, prefix, (len + 7) / 8);
dag->prefix_info.length = len;
dag->prefix_info.flags = UIP_ND6_RA_FLAG_AUTONOMOUS;
PRINTF("RPL: Prefix set - will announce this in DIOs\n");
/* Autoconfigure an address if this node does not already have an address
with this prefix. */
check_prefix(NULL, &dag->prefix_info);
return 1;
}
/*---------------------------------------------------------------------------*/
int
rpl_set_default_route(rpl_instance_t *instance, uip_ipaddr_t *from)
{
if(instance->def_route != NULL) {
PRINTF("RPL: Removing default route through ");
PRINT6ADDR(&instance->def_route->ipaddr);
PRINTF("\n");
uip_ds6_defrt_rm(instance->def_route);
instance->def_route = NULL;
}
if(from != NULL) {
PRINTF("RPL: Adding default route through ");
PRINT6ADDR(from);
PRINTF("\n");
instance->def_route = uip_ds6_defrt_add(from,
RPL_LIFETIME(instance,
instance->default_lifetime));
if(instance->def_route == NULL) {
return 0;
}
} else {
PRINTF("RPL: Removing default route\n");
if(instance->def_route != NULL) {
uip_ds6_defrt_rm(instance->def_route);
} else {
PRINTF("RPL: Not actually removing default route, since instance had no default route\n");
}
}
return 1;
}
/*---------------------------------------------------------------------------*/
rpl_instance_t *
rpl_alloc_instance(uint8_t instance_id)
{
rpl_instance_t *instance, *end;
for(instance = &instance_table[0], end = instance + RPL_MAX_INSTANCES;
instance < end; ++instance) {
if(instance->used == 0) {
memset(instance, 0, sizeof(*instance));
instance->instance_id = instance_id;
instance->def_route = NULL;
instance->used = 1;
return instance;
}
}
return NULL;
}
/*---------------------------------------------------------------------------*/
rpl_dag_t *
rpl_alloc_dag(uint8_t instance_id, uip_ipaddr_t *dag_id)
{
rpl_dag_t *dag, *end;
rpl_instance_t *instance;
instance = rpl_get_instance(instance_id);
if(instance == NULL) {
instance = rpl_alloc_instance(instance_id);
if(instance == NULL) {
RPL_STAT(rpl_stats.mem_overflows++);
return NULL;
}
}
for(dag = &instance->dag_table[0], end = dag + RPL_MAX_DAG_PER_INSTANCE; dag < end; ++dag) {
if(!dag->used) {
memset(dag, 0, sizeof(*dag));
LIST_STRUCT_INIT(dag, parents);
dag->used = 1;
dag->rank = INFINITE_RANK;
dag->min_rank = INFINITE_RANK;
dag->instance = instance;
return dag;
}
}
RPL_STAT(rpl_stats.mem_overflows++);
rpl_free_instance(instance);
return NULL;
}
/*---------------------------------------------------------------------------*/
void
rpl_set_default_instance(rpl_instance_t *instance)
{
default_instance = instance;
}
/*---------------------------------------------------------------------------*/
void
rpl_free_instance(rpl_instance_t *instance)
{
rpl_dag_t *dag;
rpl_dag_t *end;
PRINTF("RPL: Leaving the instance %u\n", instance->instance_id);
/* Remove any DAG inside this instance */
for(dag = &instance->dag_table[0], end = dag + RPL_MAX_DAG_PER_INSTANCE; dag < end; ++dag) {
if(dag->used) {
rpl_free_dag(dag);
}
}
rpl_set_default_route(instance, NULL);
ctimer_stop(&instance->dio_timer);
ctimer_stop(&instance->dao_timer);
if(default_instance == instance) {
default_instance = NULL;
}
instance->used = 0;
}
/*---------------------------------------------------------------------------*/
void
rpl_free_dag(rpl_dag_t *dag)
{
if(dag->joined) {
PRINTF("RPL: Leaving the DAG ");
PRINT6ADDR(&dag->dag_id);
PRINTF("\n");
dag->joined = 0;
/* Remove routes installed by DAOs. */
rpl_remove_routes(dag);
/* Remove autoconfigured address */
if((dag->prefix_info.flags & UIP_ND6_RA_FLAG_AUTONOMOUS)) {
check_prefix(&dag->prefix_info, NULL);
}
remove_parents(dag, 0);
}
dag->used = 0;
}
/*---------------------------------------------------------------------------*/
rpl_parent_t *
rpl_add_parent(rpl_dag_t *dag, rpl_dio_t *dio, uip_ipaddr_t *addr)
{
rpl_parent_t *p;
if(RPL_PARENT_COUNT(dag) == RPL_MAX_PARENTS_PER_DAG) {
return NULL;
}
p = memb_alloc(&parent_memb);
if(p == NULL) {
RPL_STAT(rpl_stats.mem_overflows++);
return NULL;
}
memcpy(&p->addr, addr, sizeof(p->addr));
p->dag = dag;
p->rank = dio->rank;
p->dtsn = dio->dtsn;
p->link_metric = INITIAL_LINK_METRIC;
memcpy(&p->mc, &dio->mc, sizeof(p->mc));
list_add(dag->parents, p);
return p;
}
/*---------------------------------------------------------------------------*/
rpl_parent_t *
rpl_find_parent(rpl_dag_t *dag, uip_ipaddr_t *addr)
{
rpl_parent_t *p;
for(p = list_head(dag->parents); p != NULL; p = p->next) {
if(uip_ipaddr_cmp(&p->addr, addr)) {
return p;
}
}
return NULL;
}
/*---------------------------------------------------------------------------*/
static rpl_dag_t *
find_parent_dag(rpl_instance_t *instance, uip_ipaddr_t *addr)
{
rpl_parent_t *p;
rpl_dag_t *dag, *end;
for(dag = &instance->dag_table[0], end = dag + RPL_MAX_DAG_PER_INSTANCE; dag < end; ++dag) {
if(dag->used) {
for(p = list_head(dag->parents); p != NULL; p = p->next) {
if(uip_ipaddr_cmp(&p->addr, addr)) {
return dag;
}
}
}
}
return NULL;
}
/*---------------------------------------------------------------------------*/
rpl_parent_t *
rpl_find_parent_any_dag(rpl_instance_t *instance, uip_ipaddr_t *addr)
{
rpl_parent_t *p;
rpl_dag_t *dag, *end;
for(dag = &instance->dag_table[0], end = dag + RPL_MAX_DAG_PER_INSTANCE; dag < end; ++dag) {
if(dag->used) {
for(p = list_head(dag->parents); p != NULL; p = p->next) {
if(uip_ipaddr_cmp(&p->addr, addr)) {
return p;
}
}
}
}
return NULL;
}
/*---------------------------------------------------------------------------*/
rpl_dag_t *
rpl_select_dag(rpl_instance_t *instance, rpl_parent_t *p)
{
rpl_parent_t *last_parent;
rpl_dag_t *dag, *end, *best_dag;
rpl_rank_t old_rank;
old_rank = instance->current_dag->rank;
last_parent = instance->current_dag->preferred_parent;
best_dag = instance->current_dag;
if(best_dag->rank != ROOT_RANK(instance)) {
if(rpl_select_parent(p->dag) != NULL) {
if(p->dag != best_dag) {
best_dag = instance->of->best_dag(best_dag, p->dag);
}
} else if(p->dag == best_dag) {
best_dag = NULL;
for(dag = &instance->dag_table[0], end = dag + RPL_MAX_DAG_PER_INSTANCE; dag < end; ++dag) {
if(dag->used && dag->preferred_parent != NULL && dag->preferred_parent->rank != INFINITE_RANK) {
if(best_dag == NULL) {
best_dag = dag;
} else {
best_dag = instance->of->best_dag(best_dag, dag);
}
}
}
}
}
if(best_dag == NULL) {
/* No parent found: the calling function handle this problem. */
return NULL;
}
if(instance->current_dag != best_dag) {
/* Remove routes installed by DAOs. */
rpl_remove_routes(instance->current_dag);
PRINTF("RPL: New preferred DAG: ");
PRINT6ADDR(&best_dag->dag_id);
PRINTF("\n");
if(best_dag->prefix_info.flags & UIP_ND6_RA_FLAG_AUTONOMOUS) {
check_prefix(&instance->current_dag->prefix_info, &best_dag->prefix_info);
} else if(instance->current_dag->prefix_info.flags & UIP_ND6_RA_FLAG_AUTONOMOUS) {
check_prefix(&instance->current_dag->prefix_info, NULL);
}
best_dag->joined = 1;
instance->current_dag->joined = 0;
instance->current_dag = best_dag;
}
instance->of->update_metric_container(instance);
/* Update the DAG rank. */
best_dag->rank = instance->of->calculate_rank(best_dag->preferred_parent, 0);
if(best_dag->rank < best_dag->min_rank) {
best_dag->min_rank = best_dag->rank;
} else if(!acceptable_rank(best_dag, best_dag->rank)) {
PRINTF("RPL: New rank unacceptable!\n");
instance->current_dag->preferred_parent = NULL;
if(instance->mop != RPL_MOP_NO_DOWNWARD_ROUTES && last_parent != NULL) {
/* Send a No-Path DAO to the removed preferred parent. */
dao_output(last_parent, RPL_ZERO_LIFETIME);
}
return NULL;
}
if(best_dag->preferred_parent != last_parent) {
rpl_set_default_route(instance, &best_dag->preferred_parent->addr);
PRINTF("RPL: Changed preferred parent, rank changed from %u to %u\n",
(unsigned)old_rank, best_dag->rank);
RPL_STAT(rpl_stats.parent_switch++);
if(instance->mop != RPL_MOP_NO_DOWNWARD_ROUTES) {
if(last_parent != NULL) {
/* Send a No-Path DAO to the removed preferred parent. */
dao_output(last_parent, RPL_ZERO_LIFETIME);
}
/* The DAO parent set changed - schedule a DAO transmission. */
RPL_LOLLIPOP_INCREMENT(instance->dtsn_out);
rpl_schedule_dao(instance);
}
rpl_reset_dio_timer(instance);
} else if(best_dag->rank != old_rank) {
PRINTF("RPL: Preferred parent update, rank changed from %u to %u\n",
(unsigned)old_rank, best_dag->rank);
}
return best_dag;
}
/*---------------------------------------------------------------------------*/
rpl_parent_t *
rpl_select_parent(rpl_dag_t *dag)
{
rpl_parent_t *p, *best;
best = NULL;
for(p = list_head(dag->parents); p != NULL; p = p->next) {
if(p->rank == INFINITE_RANK) {
/* ignore this neighbor */
} else if(best == NULL) {
best = p;
} else {
best = dag->instance->of->best_parent(best, p);
}
}
if(best != NULL) {
dag->preferred_parent = best;
}
return best;
}
/*---------------------------------------------------------------------------*/
void
rpl_remove_parent(rpl_dag_t *dag, rpl_parent_t *parent)
{
rpl_nullify_parent(dag, parent);
PRINTF("RPL: Removing parent ");
PRINT6ADDR(&parent->addr);
PRINTF("\n");
list_remove(dag->parents, parent);
memb_free(&parent_memb, parent);
}
/*---------------------------------------------------------------------------*/
void
rpl_nullify_parent(rpl_dag_t *dag, rpl_parent_t *parent)
{
if(parent == dag->preferred_parent) {
dag->preferred_parent = NULL;
dag->rank = INFINITE_RANK;
if(dag->joined) {
if(dag->instance->def_route != NULL) {
PRINTF("RPL: Removing default route ");
PRINT6ADDR(&parent->addr);
PRINTF("\n");
uip_ds6_defrt_rm(dag->instance->def_route);
dag->instance->def_route = NULL;
}
dao_output(parent, RPL_ZERO_LIFETIME);
}
}
PRINTF("RPL: Nullifying parent ");
PRINT6ADDR(&parent->addr);
PRINTF("\n");
}
/*---------------------------------------------------------------------------*/
void
rpl_move_parent(rpl_dag_t *dag_src, rpl_dag_t *dag_dst, rpl_parent_t *parent)
{
if(parent == dag_src->preferred_parent) {
dag_src->preferred_parent = NULL;
dag_src->rank = INFINITE_RANK;
if(dag_src->joined && dag_src->instance->def_route != NULL) {
PRINTF("RPL: Removing default route ");
PRINT6ADDR(&parent->addr);
PRINTF("\n");
PRINTF("rpl_move_parent\n");
uip_ds6_defrt_rm(dag_src->instance->def_route);
dag_src->instance->def_route = NULL;
}
} else if(dag_src->joined) {
/* Remove uIPv6 routes that have this parent as the next hop. */
rpl_remove_routes_by_nexthop(&parent->addr, dag_src);
}
PRINTF("RPL: Moving parent ");
PRINT6ADDR(&parent->addr);
PRINTF("\n");
list_remove(dag_src->parents, parent);
parent->dag = dag_dst;
list_add(dag_dst->parents, parent);
}
/*---------------------------------------------------------------------------*/
rpl_dag_t *
rpl_get_any_dag(void)
{
int i;
for(i = 0; i < RPL_MAX_INSTANCES; ++i) {
if(instance_table[i].used && instance_table[i].current_dag->joined) {
return instance_table[i].current_dag;
}
}
return NULL;
}
/*---------------------------------------------------------------------------*/
rpl_instance_t *
rpl_get_instance(uint8_t instance_id)
{
int i;
for(i = 0; i < RPL_MAX_INSTANCES; ++i) {
if(instance_table[i].used && instance_table[i].instance_id == instance_id) {
return &instance_table[i];
}
}
return NULL;
}
/*---------------------------------------------------------------------------*/
rpl_of_t *
rpl_find_of(rpl_ocp_t ocp)
{
unsigned int i;
for(i = 0;
i < sizeof(objective_functions) / sizeof(objective_functions[0]);
i++) {
if(objective_functions[i]->ocp == ocp) {
return objective_functions[i];
}
}
return NULL;
}
/*---------------------------------------------------------------------------*/
void
rpl_join_instance(uip_ipaddr_t *from, rpl_dio_t *dio)
{
rpl_instance_t *instance;
rpl_dag_t *dag;
rpl_parent_t *p;
rpl_of_t *of;
dag = rpl_alloc_dag(dio->instance_id, &dio->dag_id);
if(dag == NULL) {
PRINTF("RPL: Failed to allocate a DAG object!\n");
return;
}
instance = dag->instance;
p = rpl_add_parent(dag, dio, from);
PRINTF("RPL: Adding ");
PRINT6ADDR(from);
PRINTF(" as a parent: ");
if(p == NULL) {
PRINTF("failed\n");
instance->used = 0;
return;
}
p->dtsn = dio->dtsn;
PRINTF("succeeded\n");
/* Determine the objective function by using the
objective code point of the DIO. */
of = rpl_find_of(dio->ocp);
if(of == NULL) {
PRINTF("RPL: DIO for DAG instance %u does not specify a supported OF\n",
dio->instance_id);
rpl_remove_parent(dag, p);
instance->used = 0;
return;
}
/* Autoconfigure an address if this node does not already have an address
with this prefix. */
if(dio->prefix_info.flags & UIP_ND6_RA_FLAG_AUTONOMOUS) {
check_prefix(NULL, &dio->prefix_info);
}
dag->joined = 1;
dag->preference = dio->preference;
dag->grounded = dio->grounded;
dag->version = dio->version;
instance->of = of;
instance->mop = dio->mop;
instance->current_dag = dag;
instance->dtsn_out = RPL_LOLLIPOP_INIT;
instance->max_rankinc = dio->dag_max_rankinc;
instance->min_hoprankinc = dio->dag_min_hoprankinc;
instance->dio_intdoubl = dio->dag_intdoubl;
instance->dio_intmin = dio->dag_intmin;
instance->dio_intcurrent = instance->dio_intmin + instance->dio_intdoubl;
instance->dio_redundancy = dio->dag_redund;
instance->default_lifetime = dio->default_lifetime;
instance->lifetime_unit = dio->lifetime_unit;
memcpy(&dag->dag_id, &dio->dag_id, sizeof(dio->dag_id));
/* Copy prefix information from the DIO into the DAG object. */
memcpy(&dag->prefix_info, &dio->prefix_info, sizeof(rpl_prefix_t));
dag->preferred_parent = p;
instance->of->update_metric_container(instance);
dag->rank = instance->of->calculate_rank(p, 0);
/* So far this is the lowest rank we are aware of. */
dag->min_rank = dag->rank;
if(default_instance == NULL) {
default_instance = instance;
}
PRINTF("RPL: Joined DAG with instance ID %u, rank %hu, DAG ID ",
dio->instance_id, dag->rank);
PRINT6ADDR(&dag->dag_id);
PRINTF("\n");
ANNOTATE("#A join=%u\n", dag->dag_id.u8[sizeof(dag->dag_id) - 1]);
rpl_reset_dio_timer(instance);
rpl_set_default_route(instance, from);
if(instance->mop != RPL_MOP_NO_DOWNWARD_ROUTES) {
rpl_schedule_dao(instance);
} else {
PRINTF("RPL: The DIO does not meet the prerequisites for sending a DAO\n");
}
}
/*---------------------------------------------------------------------------*/
void
rpl_add_dag(uip_ipaddr_t *from, rpl_dio_t *dio)
{
rpl_instance_t *instance;
rpl_dag_t *dag, *previous_dag;
rpl_parent_t *p;
rpl_of_t *of;
dag = rpl_alloc_dag(dio->instance_id, &dio->dag_id);
if(dag == NULL) {
PRINTF("RPL: Failed to allocate a DAG object!\n");
return;
}
instance = dag->instance;
previous_dag = find_parent_dag(instance, from);
if(previous_dag == NULL) {
PRINTF("RPL: Adding ");
PRINT6ADDR(from);
PRINTF(" as a parent: ");
p = rpl_add_parent(dag, dio, from);
if(p == NULL) {
PRINTF("failed\n");
dag->used = 0;
return;
}
PRINTF("succeeded\n");
} else {
p = rpl_find_parent(previous_dag, from);
if(p != NULL) {
rpl_move_parent(previous_dag, dag, p);
}
}
/* Determine the objective function by using the
objective code point of the DIO. */
of = rpl_find_of(dio->ocp);
if(of != instance->of ||
instance->mop != dio->mop ||
instance->max_rankinc != dio->dag_max_rankinc ||
instance->min_hoprankinc != dio->dag_min_hoprankinc ||
instance->dio_intdoubl != dio->dag_intdoubl ||
instance->dio_intmin != dio->dag_intmin ||
instance->dio_redundancy != dio->dag_redund ||
instance->default_lifetime != dio->default_lifetime ||
instance->lifetime_unit != dio->lifetime_unit) {
PRINTF("RPL: DIO for DAG instance %u uncompatible with previos DIO\n",
dio->instance_id);
rpl_remove_parent(dag, p);
dag->used = 0;
return;
}
dag->used = 1;
dag->grounded = dio->grounded;
dag->preference = dio->preference;
dag->version = dio->version;
memcpy(&dag->dag_id, &dio->dag_id, sizeof(dio->dag_id));
/* copy prefix information into the dag */
memcpy(&dag->prefix_info, &dio->prefix_info, sizeof(rpl_prefix_t));
dag->preferred_parent = p;
dag->rank = instance->of->calculate_rank(p, 0);
dag->min_rank = dag->rank; /* So far this is the lowest rank we know of. */
PRINTF("RPL: Joined DAG with instance ID %u, rank %hu, DAG ID ",
dio->instance_id, dag->rank);
PRINT6ADDR(&dag->dag_id);
PRINTF("\n");
ANNOTATE("#A join=%u\n", dag->dag_id.u8[sizeof(dag->dag_id) - 1]);
rpl_process_parent_event(instance, p);
p->dtsn = dio->dtsn;
}
/*---------------------------------------------------------------------------*/
static void
global_repair(uip_ipaddr_t *from, rpl_dag_t *dag, rpl_dio_t *dio)
{
rpl_parent_t *p;
remove_parents(dag, 0);
dag->version = dio->version;
dag->instance->of->reset(dag);
dag->min_rank = INFINITE_RANK;
RPL_LOLLIPOP_INCREMENT(dag->instance->dtsn_out);
p = rpl_add_parent(dag, dio, from);
if(p == NULL) {
PRINTF("RPL: Failed to add a parent during the global repair\n");
dag->rank = INFINITE_RANK;
} else {
dag->rank = dag->instance->of->calculate_rank(p, 0);
dag->min_rank = dag->rank;
rpl_process_parent_event(dag->instance, p);
}
PRINTF("RPL: Participating in a global repair (version=%u, rank=%hu)\n",
dag->version, dag->rank);
RPL_STAT(rpl_stats.global_repairs++);
}
/*---------------------------------------------------------------------------*/
void
rpl_local_repair(rpl_instance_t *instance)
{
int i;
PRINTF("RPL: Starting a local instance repair\n");
for(i = 0; i < RPL_MAX_DAG_PER_INSTANCE; i++) {
if(instance->dag_table[i].used) {
instance->dag_table[i].rank = INFINITE_RANK;
nullify_parents(&instance->dag_table[i], 0);
}
}
rpl_reset_dio_timer(instance);
RPL_STAT(rpl_stats.local_repairs++);
}
/*---------------------------------------------------------------------------*/
void
rpl_recalculate_ranks(void)
{
rpl_instance_t *instance, *end;
rpl_parent_t *p;
int i;
/*
* We recalculate ranks when we receive feedback from the system rather
* than RPL protocol messages. This periodical recalculation is called
* from a timer in order to keep the stack depth reasonably low.
*/
for(instance = &instance_table[0], end = instance + RPL_MAX_INSTANCES; instance < end; ++instance) {
if(instance->used) {
for(i = 0; i < RPL_MAX_DAG_PER_INSTANCE; i++) {
if(instance->dag_table[i].used) {
for(p = list_head(instance->dag_table[i].parents); p != NULL; p = p->next) {
if(p->updated) {
p->updated = 0;
if(!rpl_process_parent_event(instance, p)) {
PRINTF("RPL: A parent was dropped\n");
}
/*
* Stop calculating here because the parent list may have changed.
* If more ranks need to be recalculated, it will be taken care of
* in subsequent calls to this functions.
*/
break;
}
}
}
}
}
}
}
/*---------------------------------------------------------------------------*/
int
rpl_process_parent_event(rpl_instance_t *instance, rpl_parent_t *p)
{
rpl_rank_t old_rank;
int return_value;
old_rank = instance->current_dag->rank;
return_value = 1;
if(!acceptable_rank(p->dag, p->rank)) {
/* The candidate parent is no longer valid: the rank increase resulting
from the choice of it as a parent would be too high. */
PRINTF("RPL: Unacceptable rank %u\n", (unsigned)p->rank);
if(p != instance->current_dag->preferred_parent) {
rpl_nullify_parent(p->dag, p);
return 0;
} else {
rpl_nullify_parent(p->dag, p);
return_value = 0;
}
}
if(rpl_select_dag(instance, p) == NULL) {
/* No suitable parent; trigger a local repair. */
PRINTF("RPL: No parents found in any DAG\n");
rpl_local_repair(instance);
return 0;
}
#if DEBUG
if(DAG_RANK(old_rank, instance) != DAG_RANK(instance->current_dag->rank, instance)) {
PRINTF("RPL: Moving in the instance from rank %hu to %hu\n",
DAG_RANK(old_rank, instance), DAG_RANK(instance->current_dag->rank, instance));
if(instance->current_dag->rank != INFINITE_RANK) {
PRINTF("RPL: The preferred parent is ");
PRINT6ADDR(&instance->current_dag->preferred_parent->addr);
PRINTF(" (rank %u)\n",
(unsigned)DAG_RANK(instance->current_dag->preferred_parent->rank, instance));
} else {
PRINTF("RPL: We don't have any parent");
}
}
#endif /* DEBUG */
return return_value;
}
/*---------------------------------------------------------------------------*/
void
rpl_process_dio(uip_ipaddr_t *from, rpl_dio_t *dio)
{
rpl_instance_t *instance;
rpl_dag_t *dag, *previous_dag;
rpl_parent_t *p;
if(dio->mop != RPL_MOP_DEFAULT) {
PRINTF("RPL: Ignoring a DIO with an unsupported MOP: %d\n", dio->mop);
return;
}
dag = get_dag(dio->instance_id, &dio->dag_id);
instance = rpl_get_instance(dio->instance_id);
if(dag != NULL && instance != NULL) {
if(lollipop_greater_than(dio->version, dag->version)) {
if(dag->rank == ROOT_RANK(instance)) {
PRINTF("RPL: Root received inconsistent DIO version number\n");
dag->version = dio->version;
RPL_LOLLIPOP_INCREMENT(dag->version);
rpl_reset_dio_timer(instance);
} else {
global_repair(from, dag, dio);
}
return;
}
if(lollipop_greater_than(dag->version, dio->version)) {
/* The DIO sender is on an older version of the DAG. */
PRINTF("RPL: old version received => inconsistency detected\n");
if(dag->joined) {
rpl_reset_dio_timer(instance);
return;
}
}
}
if(dio->rank == INFINITE_RANK) {
PRINTF("RPL: Ignoring DIO from node with infinite rank: ");
PRINT6ADDR(from);
PRINTF("\n");
return;
}
if(instance == NULL) {
PRINTF("RPL: New instance detected: Joining...\n");
rpl_join_instance(from, dio);
return;
}
if(dag == NULL) {
PRINTF("RPL: Adding new DAG to known instance.\n");
rpl_add_dag(from, dio);
return;
}
if(dio->rank < ROOT_RANK(instance)) {
PRINTF("RPL: Ignoring DIO with too low rank: %u\n",
(unsigned)dio->rank);
return;
} else if(dio->rank == INFINITE_RANK && dag->joined) {
rpl_reset_dio_timer(instance);
}
if(dag->rank == ROOT_RANK(instance)) {
if(dio->rank != INFINITE_RANK) {
instance->dio_counter++;
}
return;
}
/*
* At this point, we know that this DIO pertains to a DAG that
* we are already part of. We consider the sender of the DIO to be
* a candidate parent, and let rpl_process_parent_event decide
* whether to keep it in the set.
*/
p = rpl_find_parent(dag, from);
if(p == NULL) {
previous_dag = find_parent_dag(instance, from);
if(previous_dag == NULL) {
if(RPL_PARENT_COUNT(dag) == RPL_MAX_PARENTS_PER_DAG) {
/* Make room for a new parent. */
remove_worst_parent(dag, dio->rank);
}
/* Add the DIO sender as a candidate parent. */
p = rpl_add_parent(dag, dio, from);
if(p == NULL) {
PRINTF("RPL: Failed to add a new parent (");
PRINT6ADDR(from);
PRINTF(")\n");
return;
}
PRINTF("RPL: New candidate parent with rank %u: ", (unsigned)p->rank);
PRINT6ADDR(from);
PRINTF("\n");
} else {
p = rpl_find_parent(previous_dag, from);
if(p != NULL) {
rpl_move_parent(previous_dag, dag, p);
}
}
} else {
if(p->rank == dio->rank) {
PRINTF("RPL: Received consistent DIO\n");
if(dag->joined) {
instance->dio_counter++;
}
} else {
p->rank=dio->rank;
}
}
PRINTF("RPL: preferred DAG ");
PRINT6ADDR(&instance->current_dag->dag_id);
PRINTF(", rank %u, min_rank %u, ",
instance->current_dag->rank, instance->current_dag->min_rank);
PRINTF("parent rank %u, parent etx %u, link metric %u, instance etx %u\n",
p->rank, p->mc.obj.etx, p->link_metric, instance->mc.obj.etx);
/* We have allocated a candidate parent; process the DIO further. */
memcpy(&p->mc, &dio->mc, sizeof(p->mc));
if(rpl_process_parent_event(instance, p) == 0) {
PRINTF("RPL: The candidate parent is rejected\n");
return;
}
/* We don't use route control, so we can have only one official parent. */
if(dag->joined && p == dag->preferred_parent) {
if(should_send_dao(instance, dio, p)) {
RPL_LOLLIPOP_INCREMENT(instance->dtsn_out);
rpl_schedule_dao(instance);
}
}
p->dtsn = dio->dtsn;
}
/*---------------------------------------------------------------------------*/
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