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osd-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.
*
* $Id: rpl-dag.c,v 1.43 2011/01/04 20:43:28 nvt-se Exp $
*/
/**
* \file
* Logic for Directed Acyclic Graphs in RPL.
*
* \author Joakim Eriksson <joakime@sics.se>, Nicolas Tsiftes <nvt@sics.se>
*/
#include "net/rpl/rpl.h"
#include "contiki.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"
/************************************************************************/
extern rpl_of_t RPL_OF;
static rpl_of_t * const objective_functions[] = {&RPL_OF};
/************************************************************************/
#ifndef RPL_CONF_MAX_DAG_ENTRIES
#define RPL_MAX_DAG_ENTRIES 2
#else
#define RPL_MAX_DAG_ENTRIES RPL_CONF_MAX_DAG_ENTRIES
#endif /* !RPL_CONF_MAX_DAG_ENTRIES */
#ifndef RPL_CONF_MAX_PARENTS
#define RPL_MAX_PARENTS 8
#else
#define RPL_MAX_PARENTS RPL_CONF_MAX_PARENTS
#endif /* !RPL_CONF_MAX_PARENTS */
/************************************************************************/
/* RPL definitions. */
#ifndef RPL_CONF_GROUNDED
#define RPL_GROUNDED 0
#else
#define RPL_GROUNDED RPL_CONF_GROUNDED
#endif /* !RPL_CONF_GROUNDED */
#ifndef RPL_CONF_DIO_INTERVAL_MIN
#define RPL_DIO_INTERVAL_MIN DEFAULT_DIO_INTERVAL_MIN
#else
#define RPL_DIO_INTERVAL_MIN RPL_CONF_DIO_INTERVAL_MIN
#endif /* !RPL_CONF_DIO_INTERVAL_MIN */
#ifndef RPL_CONF_DIO_INTERVAL_DOUBLINGS
#define RPL_DIO_INTERVAL_DOUBLINGS DEFAULT_DIO_INTERVAL_DOUBLINGS
#else
#define RPL_DIO_INTERVAL_DOUBLINGS RPL_CONF_DIO_INTERVAL_DOUBLINGS
#endif /* !RPL_CONF_DIO_INTERVAL_DOUBLINGS */
/************************************************************************/
/* Allocate parents from the same static MEMB chunk to reduce memory waste. */
MEMB(parent_memb, struct rpl_parent, RPL_MAX_PARENTS);
static rpl_dag_t dag_table[RPL_MAX_DAG_ENTRIES];
/************************************************************************/
/* 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 int
should_send_dao(rpl_dag_t *dag, rpl_dio_t *dio, rpl_parent_t *p)
{
return dio->dtsn > p->dtsn && p == dag->preferred_parent;
}
/************************************************************************/
static int
acceptable_rank(rpl_dag_t *dag, rpl_rank_t rank)
{
return rank != INFINITE_RANK &&
(dag->max_rankinc == 0 ||
DAG_RANK(rank, dag) <= DAG_RANK(dag->min_rank + dag->max_rankinc, dag));
}
/************************************************************************/
rpl_dag_t *
rpl_set_root(uip_ipaddr_t *dag_id)
{
rpl_dag_t *dag;
int version;
version = -1;
dag = rpl_get_dag(RPL_DEFAULT_INSTANCE);
if(dag != NULL) {
PRINTF("RPL: Dropping a joined DAG when setting this node as root");
version = dag->version;
rpl_free_dag(dag);
}
dag = rpl_alloc_dag(RPL_DEFAULT_INSTANCE);
if(dag == NULL) {
PRINTF("RPL: Failed to allocate a DAG\n");
return NULL;
}
dag->joined = 1;
dag->version = version + 1;
dag->grounded = RPL_GROUNDED;
dag->mop = RPL_MOP_DEFAULT;
dag->rank = ROOT_RANK;
dag->of = &RPL_OF;
dag->preferred_parent = NULL;
dag->dtsn_out = 1; /* Trigger DAOs from the beginning. */
memcpy(&dag->dag_id, dag_id, sizeof(dag->dag_id));
dag->dio_intdoubl = DEFAULT_DIO_INTERVAL_DOUBLINGS;
dag->dio_intmin = DEFAULT_DIO_INTERVAL_MIN;
dag->dio_redundancy = DEFAULT_DIO_REDUNDANCY;
dag->max_rankinc = DEFAULT_MAX_RANKINC;
dag->min_hoprankinc = DEFAULT_MIN_HOPRANKINC;
dag->default_lifetime = DEFAULT_RPL_DEF_LIFETIME;
dag->lifetime_unit = DEFAULT_RPL_LIFETIME_UNIT;
PRINTF("RPL: Node set to be a DAG root with DAG ID ");
PRINT6ADDR(&dag->dag_id);
PRINTF("\n");
rpl_reset_dio_timer(dag, 1);
return dag;
}
/************************************************************************/
int
rpl_set_prefix(rpl_dag_t *dag, uip_ipaddr_t *prefix, int len)
{
if(len <= 128) {
memset(&dag->prefix_info.prefix, 0, 16);
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");
return 1;
}
return 0;
}
/************************************************************************/
int
rpl_set_default_route(rpl_dag_t *dag, uip_ipaddr_t *from)
{
if(dag->def_route != NULL) {
PRINTF("RPL: Removing default route through ");
PRINT6ADDR(&dag->def_route->ipaddr);
PRINTF("\n");
uip_ds6_defrt_rm(dag->def_route);
}
if(from != NULL) {
PRINTF("RPL: Adding default route through ");
PRINT6ADDR(from);
PRINTF("\n");
if(DEFAULT_ROUTE_LIFETIME == INFINITE_LIFETIME) {
dag->def_route = uip_ds6_defrt_add(from, 0);
} else {
dag->def_route = uip_ds6_defrt_add(from, DEFAULT_ROUTE_LIFETIME);
}
if(dag->def_route == NULL) {
return 0;
}
}
return 1;
}
/************************************************************************/
rpl_dag_t *
rpl_alloc_dag(uint8_t instance_id)
{
rpl_dag_t *dag;
rpl_dag_t *end;
for(dag = &dag_table[0], end = dag + RPL_MAX_DAG_ENTRIES; dag < end; dag++) {
if(dag->used == 0) {
memset(dag, 0, sizeof(*dag));
dag->parents = &dag->parent_list;
list_init(dag->parents);
dag->instance_id = instance_id;
dag->def_route = NULL;
dag->rank = INFINITE_RANK;
dag->min_rank = INFINITE_RANK;
return dag;
}
}
RPL_STAT(rpl_stats.mem_overflows++);
return NULL;
}
/************************************************************************/
void
rpl_free_dag(rpl_dag_t *dag)
{
PRINTF("RPL: Leaving the DAG ");
PRINT6ADDR(&dag->dag_id);
PRINTF("\n");
/* Remove routes installed by DAOs. */
rpl_remove_routes(dag);
/* Remove parents and the default route. */
remove_parents(dag, 0);
rpl_set_default_route(dag, NULL);
ctimer_stop(&dag->dio_timer);
ctimer_stop(&dag->dao_timer);
dag->used = 0;
dag->joined = 0;
}
/************************************************************************/
rpl_parent_t *
rpl_add_parent(rpl_dag_t *dag, rpl_dio_t *dio, uip_ipaddr_t *addr)
{
rpl_parent_t *p;
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->local_confidence = 0;
p->dtsn = 0;
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;
}
/************************************************************************/
rpl_parent_t *
rpl_select_parent(rpl_dag_t *dag)
{
rpl_parent_t *p;
rpl_parent_t *best;
best = NULL;
for(p = list_head(dag->parents); p != NULL; p = p->next) {
if(best == NULL) {
best = p;
} else {
best = dag->of->best_parent(best, p);
}
}
if(dag->preferred_parent != best) {
dag->preferred_parent = best; /* Cache the value. */
rpl_set_default_route(dag, &best->addr);
/* The DAO parent set changed - schedule a DAO transmission. */
rpl_schedule_dao(dag);
rpl_reset_dio_timer(dag, 1);
PRINTF("RPL: New preferred parent, rank changed from %u to %u\n",
(unsigned)dag->rank, dag->of->calculate_rank(best, 0));
}
/* Update the DAG rank, since link-layer information may have changed
the local confidence. */
dag->rank = dag->of->calculate_rank(best, 0);
if(dag->rank < dag->min_rank) {
dag->min_rank = dag->rank;
} else if(!acceptable_rank(dag, best->rank)) {
/* Send a No-Path DAO to the soon-to-be-removed preferred parent. */
dao_output(p, ZERO_LIFETIME);
remove_parents(dag, 0);
return NULL;
}
return best;
}
/************************************************************************/
int
rpl_remove_parent(rpl_dag_t *dag, rpl_parent_t *parent)
{
uip_ds6_defrt_t *defrt;
/* Remove uIPv6 routes that have this parent as the next hop. **/
uip_ds6_route_rm_by_nexthop(&parent->addr);
defrt = uip_ds6_defrt_lookup(&parent->addr);
if(defrt != NULL) {
PRINTF("RPL: Removing default route ");
PRINT6ADDR(&parent->addr);
PRINTF("\n");
uip_ds6_defrt_rm(defrt);
dag->def_route = NULL;
}
PRINTF("RPL: Removing parent ");
PRINT6ADDR(&parent->addr);
PRINTF("\n");
if(parent == dag->preferred_parent) {
dag->preferred_parent = NULL;
}
list_remove(dag->parents, parent);
memb_free(&parent_memb, parent);
return 0;
}
/************************************************************************/
rpl_dag_t *
rpl_get_dag(int instance_id)
{
int i;
for(i = 0; i < RPL_MAX_DAG_ENTRIES; i++) {
if(dag_table[i].joined && (instance_id == RPL_ANY_INSTANCE ||
dag_table[i].instance_id == instance_id)) {
return &dag_table[i];
}
}
return NULL;
}
/************************************************************************/
rpl_of_t *
rpl_find_of(rpl_ocp_t ocp)
{
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;
}
/************************************************************************/
static void
join_dag(uip_ipaddr_t *from, rpl_dio_t *dio)
{
rpl_dag_t *dag;
rpl_parent_t *p;
rpl_of_t *of;
dag = rpl_alloc_dag(dio->instance_id);
if(dag == NULL) {
PRINTF("RPL: Failed to allocate a DAG object!\n");
return;
}
p = rpl_add_parent(dag, dio, from);
PRINTF("RPL: Adding ");
PRINT6ADDR(from);
PRINTF(" as a parent: ");
if(p == NULL) {
PRINTF("failed\n");
return;
}
PRINTF("succeeded\n");
p->local_confidence = 0; /* The lowest confidence for new parents. */
/* 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);
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)) {
uip_ipaddr_t ipaddr;
/* assume that the prefix ends with zeros! */
memcpy(&ipaddr, &dio->prefix_info.prefix, 16);
uip_ds6_set_addr_iid(&ipaddr, &uip_lladdr);
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);
}
}
dag->joined = 1;
dag->used = 1;
dag->of = of;
dag->grounded = dio->grounded;
dag->mop = dio->mop;
dag->preference = dio->preference;
dag->instance_id = dio->instance_id;
dag->max_rankinc = dio->dag_max_rankinc;
dag->min_hoprankinc = dio->dag_min_hoprankinc;
dag->version = dio->version;
dag->preferred_parent = p;
dag->dio_intdoubl = dio->dag_intdoubl;
dag->dio_intmin = dio->dag_intmin;
dag->dio_redundancy = dio->dag_redund;
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));
PRINTF("RPL: Joined DAG with instance ID %u, rank %hu, DAG ID ",
dio->instance_id, dag->rank);
PRINT6ADDR(&dag->dag_id);
PRINTF("\n");
dag->rank = dag->of->calculate_rank(p, dio->rank);
dag->min_rank = dag->rank; /* So far this is the lowest rank we know of. */
dag->default_lifetime = dio->default_lifetime;
dag->lifetime_unit = dio->lifetime_unit;
rpl_reset_dio_timer(dag, 1);
rpl_set_default_route(dag, from);
if(should_send_dao(dag, dio, p)) {
rpl_schedule_dao(dag);
} else {
PRINTF("RPL: The DIO does not meet the prerequisites for sending a DAO\n");
}
}
/************************************************************************/
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->dtsn_out = 1;
dag->of->reset(dag);
if((p = rpl_add_parent(dag, dio, from)) == NULL) {
PRINTF("RPL: Failed to add a parent during the global repair\n");
dag->rank = INFINITE_RANK;
} else {
rpl_set_default_route(dag, from);
dag->rank = dag->of->calculate_rank(NULL, dio->rank);
dag->min_rank = dag->rank;
rpl_reset_dio_timer(dag, 1);
if(should_send_dao(dag, dio, p)) {
rpl_schedule_dao(dag);
}
}
PRINTF("RPL: Participating in a global repair (version=%u, rank=%hu)\n",
dag->version, dag->rank);
RPL_STAT(rpl_stats.global_repairs++);
}
/************************************************************************/
int
rpl_repair_dag(rpl_dag_t *dag)
{
if(dag->rank == ROOT_RANK) {
dag->version++;
dag->dtsn_out = 1;
rpl_reset_dio_timer(dag, 1);
return 1;
}
return 0;
}
/************************************************************************/
void
rpl_local_repair(rpl_dag_t *dag)
{
PRINTF("RPL: Starting a local DAG repair\n");
dag->rank = INFINITE_RANK;
remove_parents(dag, 0);
rpl_reset_dio_timer(dag, 1);
RPL_STAT(rpl_stats.local_repairs++);
}
/************************************************************************/
void
rpl_recalculate_ranks(void)
{
rpl_dag_t *dag;
rpl_parent_t *p;
/*
* 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.
*/
dag = rpl_get_dag(RPL_ANY_INSTANCE);
if(dag != NULL) {
for(p = list_head(dag->parents); p != NULL; p = p->next) {
if(p->updated) {
p->updated = 0;
rpl_process_parent_event(dag, p);
/*
* 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_dag_t *dag, rpl_parent_t *p)
{
rpl_rank_t parent_rank;
rpl_rank_t old_rank;
/* Update the parent rank. */
parent_rank = p->rank;
old_rank = dag->rank;
if(rpl_select_parent(dag) == NULL) {
/* No suitable parent; trigger a local repair. */
PRINTF("RPL: No parents found in a DAG\n");
rpl_local_repair(dag);
return 1;
}
if(DAG_RANK(old_rank, dag) != DAG_RANK(dag->rank, dag)) {
if(dag->rank < dag->min_rank) {
dag->min_rank = dag->rank;
}
PRINTF("RPL: Moving in the DAG from rank %hu to %hu\n",
DAG_RANK(old_rank, dag), DAG_RANK(dag->rank, dag));
PRINTF("RPL: The preferred parent is ");
PRINT6ADDR(&dag->preferred_parent->addr);
PRINTF(" (rank %u)\n",
(unsigned)DAG_RANK(dag->preferred_parent->rank, dag));
rpl_reset_dio_timer(dag, 1);
}
if(!acceptable_rank(dag, dag->of->calculate_rank(NULL, parent_rank))) {
/* The candidate parent is no longer valid: the rank increase resulting
from the choice of it as a parent would be too high. */
return 0;
}
return 1;
}
/************************************************************************/
void
rpl_process_dio(uip_ipaddr_t *from, rpl_dio_t *dio)
{
rpl_dag_t *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 = rpl_get_dag(dio->instance_id);
if(dag == NULL) {
/* Join the first possible DAG of this RPL instance. */
if(dio->rank != INFINITE_RANK) {
join_dag(from, dio);
} else {
PRINTF("RPL: Ignoring DIO from node with infinite rank: ");
PRINT6ADDR(from);
PRINTF("\n");
}
return;
}
if(memcmp(&dag->dag_id, &dio->dag_id, sizeof(dag->dag_id))) {
PRINTF("RPL: Ignoring DIO for another DAG within our instance\n");
return;
}
if(dio->version > dag->version) {
if(dag->rank == ROOT_RANK) {
PRINTF("RPL: Root received inconsistent DIO version number\n");
dag->version = dio->version + 1;
rpl_reset_dio_timer(dag, 1);
} else {
global_repair(from, dag, dio);
}
return;
} else if(dio->version < dag->version) {
/* Inconsistency detected - someone is still on old version */
PRINTF("RPL: old version received => inconsistency detected\n");
rpl_reset_dio_timer(dag, 1);
return;
}
if(dio->rank == INFINITE_RANK) {
rpl_reset_dio_timer(dag, 1);
}
if(dag->rank == ROOT_RANK) {
if(dio->rank != INFINITE_RANK) {
dag->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) {
if(RPL_PARENT_COUNT(dag) == RPL_MAX_PARENTS) {
/* Try to make room for a new parent. */
remove_parents(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 if(DAG_RANK(p->rank, dag) == DAG_RANK(dio->rank, dag)) {
PRINTF("RPL: Received consistent DIO\n");
dag->dio_counter++;
}
/* We have allocated a candidate parent; process the DIO further. */
p->rank = dio->rank;
if(rpl_process_parent_event(dag, p) == 0) {
/* The candidate parent no longer exists. */
return;
}
if(should_send_dao(dag, dio, p)) {
rpl_schedule_dao(dag);
}
p->dtsn = dio->dtsn;
}
/************************************************************************/
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