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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 1.24 2010/06/08 16:21:54 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 "net/uip.h"
#include "net/uip-nd6.h"
#include "net/rime/ctimer.h"
#include "lib/list.h"
#include "lib/memb.h"
#include <limits.h>
#include <string.h>
#define DEBUG DEBUG_ANNOTATE
#include "net/uip-debug.h"
/************************************************************************/
extern rpl_of_t rpl_of_etx;
static rpl_of_t *objective_functions[] = {&rpl_of_etx, NULL};
/************************************************************************/
#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 4
#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];
#define POISON_ROUTES 1
/************************************************************************/
static void
remove_parents(rpl_dag_t *dag, rpl_parent_t *exception, int poison_routes)
{
rpl_parent_t *p, *p2;
PRINTF("RPL: Removing parents %s poisoning routes\n",
poison_routes == POISON_ROUTES ? "and" : "without");
for(p = list_head(dag->parents); p != NULL;) {
if(p != exception) {
if(poison_routes == POISON_ROUTES) {
/* Send no-DAOs to old parents. */
dao_output(p, ZERO_LIFETIME);
}
p2 = p->next;
rpl_remove_parent(dag, p);
p = p2;
} else {
p = p->next;
}
}
}
/************************************************************************/
static int
should_send_dao(rpl_dag_t *dag, rpl_dio_t *dio, rpl_parent_t *p)
{
return dio->dst_adv_supported && dio->dst_adv_trigger &&
dio->dtsn > p->dtsn && p == dag->best_parent;
}
/************************************************************************/
static int
acceptable_rank_increase(rpl_dag_t *dag, rpl_parent_t *p)
{
return !dag->max_rankinc ||
dag->of->increment_rank(p->rank, p) <= dag->min_rank + dag->max_rankinc;
}
/************************************************************************/
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_OCP);
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();
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->rank = ROOT_RANK;
dag->of = rpl_find_of(RPL_DEFAULT_OCP);
dag->best_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;
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(void)
{
int i;
for(i = 0; i < RPL_MAX_DAG_ENTRIES; i++) {
if(dag_table[i].used == 0) {
memset(&dag_table[i], 0, sizeof(dag_table[0]));
dag_table[i].parents = &dag_table[i].parent_list;
list_init(dag_table[i].parents);
dag_table[i].def_route = NULL;
return &dag_table[i];
}
}
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, NULL, !POISON_ROUTES);
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) {
return NULL;
}
memcpy(&p->addr, addr, sizeof(p->addr));
p->dag = dag;
p->rank = dio->dag_rank;
p->local_confidence = 0;
p->dtsn = 0;
list_add(dag->parents, p);
/* Draw a line between the node and its parent in Cooja. */
ANNOTATE("#L %u 1\n", addr->u8[sizeof(*addr) - 1]);
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_preferred_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->best_parent != best) {
dag->best_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);
}
return best;
}
/************************************************************************/
int
rpl_remove_parent(rpl_dag_t *dag, rpl_parent_t *parent)
{
uip_ds6_defrt_t *defrt;
ANNOTATE("#L %u 0\n",
parent->addr.u8[sizeof(parent->addr) - 1]);
/* 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");
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)
{
rpl_of_t *of;
for(of = objective_functions[0]; of != NULL; of++) {
if(of->ocp == ocp) {
return of;
}
}
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();
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->preference = dio->preference;
dag->grounded = dio->grounded;
dag->instance_id = dio->instance_id;
dag->rank = dag->of->increment_rank(dio->dag_rank, p);
dag->min_rank = dag->rank; /* So far this is the lowest rank we know */
dag->version = dio->version;
dag->best_parent = p;
dag->dio_intdoubl = dio->dag_intdoubl;
dag->dio_intmin = dio->dag_intmin;
dag->dio_redundancy = dio->dag_redund;
dag->max_rankinc = dio->dag_max_rankinc;
dag->min_hoprankinc = dio->dag_min_hoprankinc;
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");
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: dst_adv_trigger not set in incoming DIO!\n");
}
}
/************************************************************************/
static void
global_repair(uip_ipaddr_t *from, rpl_dag_t *dag, rpl_dio_t *dio)
{
rpl_parent_t *p;
remove_parents(dag, NULL, !POISON_ROUTES);
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->increment_rank(dio->dag_rank, p);
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);
}
/************************************************************************/
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_process_dio(uip_ipaddr_t *from, rpl_dio_t *dio)
{
rpl_dag_t *dag;
rpl_parent_t *p;
rpl_parent_t *preferred_parent;
rpl_rank_t new_rank;
uint8_t new_parent;
dag = rpl_get_dag(dio->instance_id);
if(dag == NULL) {
/* Always join the first possible DAG that is not of INF_RANK. */
if(dio->dag_rank != INFINITE_RANK) {
join_dag(from, dio);
} else {
PRINTF("RPL: Ignoring DIO from node with infinite rank: ");
PRINT6ADDR(from);
PRINTF("\n");
}
return;
}
if(dag->instance_id != dio->instance_id) {
/* We avoid joining more than one RPL instance. */
PRINTF("RPL: Cannot join another RPL instance\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;
}
/* This DIO pertains to a DAG that we are already part of. */
p = rpl_find_parent(dag, from);
if(p != NULL) {
if(should_send_dao(dag, dio, p)) {
rpl_schedule_dao(dag);
}
p->dtsn = dio->dtsn;
if(p->rank > dio->dag_rank) {
p->rank = dio->dag_rank;
rpl_reset_dio_timer(dag, 1);
} else if(p->rank < dio->dag_rank) {
PRINTF("RPL: Existing parent ");
PRINT6ADDR(from);
PRINTF(" got a higher rank (%hu -> %hu)\n",
p->rank, dio->dag_rank);
p->rank = dio->dag_rank;
if(RPL_PARENT_COUNT(dag) > 1) {
/* Since we have alternative parents, we can simply drop this one. */
rpl_remove_parent(dag, p);
p = rpl_preferred_parent(dag);
if(p != NULL) {
rpl_set_default_route(dag, &p->addr);
}
return;
} else if(dag->of->increment_rank(dio->dag_rank, p) <= dag->min_rank + dag->max_rankinc) {
preferred_parent = rpl_preferred_parent(dag);
if(p == preferred_parent) {
new_rank = dag->of->increment_rank(dio->dag_rank, p);
rpl_set_default_route(dag, &p->addr);
dag->rank = new_rank;
PRINTF("RPL: New rank is %hu, max is %hu\n",
dag->rank, dag->min_rank + dag->max_rankinc);
}
} else {
PRINTF("RPL: Cannot find an acceptable preferred parent\n");
/* do local repair - jump down the DAG */
remove_parents(dag, NULL, POISON_ROUTES);
dag->rank = INFINITE_RANK;
}
rpl_reset_dio_timer(dag, 1);
} else {
/* Assume consistency and increase the DIO counter. */
PRINTF("RPL: Received a consistent DIO\n");
dag->dio_counter++;
}
}
if(dio->dag_rank < dag->rank) {
/* Message from a node closer to the root, but we might still be out of allowed rank-range */
if(dag->max_rankinc > 0 && dag->min_rank + dag->max_rankinc <
dag->of->increment_rank(dio->dag_rank, NULL)) {
PRINTF("RPL: Could not add parent, resulting rank too high\n");
return;
}
new_parent = 0;
if(p == NULL) {
p = rpl_add_parent(dag, dio, from);
if(p == NULL) {
PRINTF("RPL: Could not add parent\n");
return;
}
PRINTF("RPL: New parent with rank %hu: ", p->rank);
PRINT6ADDR(from);
PRINTF("\n");
new_parent = 1;
}
new_rank = dag->of->increment_rank(dio->dag_rank, p);
if(new_rank < dag->rank) {
PRINTF("RPL: Moving up within the DAG from rank %hu to %hu\n",
dag->rank, new_rank);
dag->rank = new_rank;
dag->min_rank = new_rank; /* So far this is the lowest rank we know */
rpl_reset_dio_timer(dag, 1);
/* Remove old def-route and add the new */
/* fix handling of destination prefix */
rpl_set_default_route(dag, from);
if(new_parent) {
remove_parents(dag, p, POISON_ROUTES);
}
}
} else if(dio->dag_rank == dag->rank) {
/* Message from a sibling. */
} else {
/* Message from a node at a longer distance from the root. If the
node is in the parent list, we just remove it. */
if(p != NULL && p->rank < dio->dag_rank) {
PRINTF("RPL: Parent ");
PRINT6ADDR(&p->addr);
PRINTF(" has increased in rank from %hu to %hu. Removing it.\n",
p->rank, dio->dag_rank);
rpl_remove_parent(dag, p);
if(RPL_PARENT_COUNT(dag) == 0) {
dag->rank = INFINITE_RANK;
}
}
}
}
/************************************************************************/
void
rpl_ds6_neighbor_callback(uip_ds6_nbr_t *nbr)
{
rpl_dag_t *dag;
rpl_parent_t *p;
rpl_parent_t *new_p;
if(nbr->isused) {
PRINTF("RPL: Neighbor state %u: ", nbr->state);
PRINT6ADDR(&nbr->ipaddr);
PRINTF("\n");
return;
}
PRINTF("RPL: Removing neighbor ");
PRINT6ADDR(&nbr->ipaddr);
PRINTF("\n");
dag = rpl_get_dag(RPL_ANY_INSTANCE);
if(dag == NULL) {
return;
}
p = rpl_find_parent(dag, &nbr->ipaddr);
if(p != NULL) {
if(p == dag->best_parent) {
/* Try to select a new preferred parent. */
new_p = rpl_preferred_parent(dag);
if(new_p == NULL) {
rpl_free_dag(dag);
return;
}
if(acceptable_rank_increase(dag, new_p)) {
dag->rank = dag->of->increment_rank(new_p->rank, new_p);
if(dag->rank < dag->min_rank) {
dag->min_rank = dag->rank;
}
PRINTF("RPL: New rank is %hu, max is %hu\n",
dag->rank, dag->min_rank + dag->max_rankinc);
rpl_set_default_route(dag, &new_p->addr);
} else {
PRINTF("RPL: Cannot select the preferred parent\n");
/* do local repair - jump down the DAG */
rpl_set_default_route(dag, NULL);
remove_parents(dag, NULL, POISON_ROUTES);
dag->rank = INFINITE_RANK;
rpl_reset_dio_timer(dag, 1);
}
}
rpl_remove_parent(dag, p);
}
}
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