nes-proj/core/net/rime/route.c

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/*
* Copyright (c) 2007, 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
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* Rime route table
* \author
* Adam Dunkels <adam@sics.se>
*/
/**
* \addtogroup rimeroute
* @{
*/
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#include <stdio.h>
#include "lib/list.h"
#include "lib/memb.h"
#include "sys/ctimer.h"
#include "net/rime/route.h"
#include "contiki-conf.h"
#ifdef ROUTE_CONF_ENTRIES
#define NUM_RT_ENTRIES ROUTE_CONF_ENTRIES
#else /* ROUTE_CONF_ENTRIES */
#define NUM_RT_ENTRIES 8
#endif /* ROUTE_CONF_ENTRIES */
#ifdef ROUTE_CONF_DECAY_THRESHOLD
#define DECAY_THRESHOLD ROUTE_CONF_DECAY_THRESHOLD
#else /* ROUTE_CONF_DECAY_THRESHOLD */
#define DECAY_THRESHOLD 8
#endif /* ROUTE_CONF_DECAY_THRESHOLD */
#ifdef ROUTE_CONF_DEFAULT_LIFETIME
#define DEFAULT_LIFETIME ROUTE_CONF_DEFAULT_LIFETIME
#else /* ROUTE_CONF_DEFAULT_LIFETIME */
#define DEFAULT_LIFETIME 60
#endif /* ROUTE_CONF_DEFAULT_LIFETIME */
/*
* List of route entries.
*/
LIST(route_table);
MEMB(route_mem, struct route_entry, NUM_RT_ENTRIES);
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static struct ctimer t;
static int max_time = DEFAULT_LIFETIME;
#define DEBUG 0
#if DEBUG
#include <stdio.h>
#define PRINTF(...) printf(__VA_ARGS__)
#else
#define PRINTF(...)
#endif
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/*---------------------------------------------------------------------------*/
static void
periodic(void *ptr)
{
struct route_entry *e;
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for(e = list_head(route_table); e != NULL; e = list_item_next(e)) {
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e->time++;
if(e->time >= max_time) {
PRINTF("route periodic: removing entry to %d.%d with nexthop %d.%d and cost %d\n",
e->dest.u8[0], e->dest.u8[1],
e->nexthop.u8[0], e->nexthop.u8[1],
e->cost);
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list_remove(route_table, e);
memb_free(&route_mem, e);
}
}
ctimer_set(&t, CLOCK_SECOND, periodic, NULL);
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}
/*---------------------------------------------------------------------------*/
void
route_init(void)
{
list_init(route_table);
memb_init(&route_mem);
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ctimer_set(&t, CLOCK_SECOND, periodic, NULL);
}
/*---------------------------------------------------------------------------*/
int
route_add(const linkaddr_t *dest, const linkaddr_t *nexthop,
uint8_t cost, uint8_t seqno)
{
struct route_entry *e, *oldest = NULL;
/* Avoid inserting duplicate entries. */
e = route_lookup(dest);
if(e != NULL && linkaddr_cmp(&e->nexthop, nexthop)) {
list_remove(route_table, e);
} else {
/* Allocate a new entry or reuse the oldest entry with highest cost. */
e = memb_alloc(&route_mem);
if(e == NULL) {
/* Remove oldest entry. */
for(e = list_head(route_table); e != NULL; e = list_item_next(e)) {
if(oldest == NULL || e->time >= oldest->time) {
oldest = e;
}
}
e = oldest;
list_remove(route_table, e);
PRINTF("route_add: removing entry to %d.%d with nexthop %d.%d and cost %d\n",
e->dest.u8[0], e->dest.u8[1],
e->nexthop.u8[0], e->nexthop.u8[1],
e->cost);
}
}
linkaddr_copy(&e->dest, dest);
linkaddr_copy(&e->nexthop, nexthop);
e->cost = cost;
e->seqno = seqno;
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e->time = 0;
e->decay = 0;
/* New entry goes first. */
list_push(route_table, e);
PRINTF("route_add: new entry to %d.%d with nexthop %d.%d and cost %d\n",
e->dest.u8[0], e->dest.u8[1],
e->nexthop.u8[0], e->nexthop.u8[1],
e->cost);
return 0;
}
/*---------------------------------------------------------------------------*/
struct route_entry *
route_lookup(const linkaddr_t *dest)
{
struct route_entry *e;
uint8_t lowest_cost;
struct route_entry *best_entry;
lowest_cost = -1;
best_entry = NULL;
/* Find the route with the lowest cost. */
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for(e = list_head(route_table); e != NULL; e = list_item_next(e)) {
/* printf("route_lookup: comparing %d.%d.%d.%d with %d.%d.%d.%d\n",
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uip_ipaddr_to_quad(dest), uip_ipaddr_to_quad(&e->dest));*/
if(linkaddr_cmp(dest, &e->dest)) {
if(e->cost < lowest_cost) {
best_entry = e;
lowest_cost = e->cost;
}
}
}
return best_entry;
}
/*---------------------------------------------------------------------------*/
void
route_refresh(struct route_entry *e)
{
if(e != NULL) {
/* Refresh age of route so that used routes do not get thrown
out. */
e->time = 0;
e->decay = 0;
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PRINTF("route_refresh: time %d last %d decay %d for entry to %d.%d with nexthop %d.%d and cost %d\n",
e->time, e->time_last_decay, e->decay,
e->dest.u8[0], e->dest.u8[1],
e->nexthop.u8[0], e->nexthop.u8[1],
e->cost);
}
}
/*---------------------------------------------------------------------------*/
void
route_decay(struct route_entry *e)
{
/* If routes are not refreshed, they decay over time. This function
is called to decay a route. The route can only be decayed once
per second. */
PRINTF("route_decay: time %d last %d decay %d for entry to %d.%d with nexthop %d.%d and cost %d\n",
e->time, e->time_last_decay, e->decay,
e->dest.u8[0], e->dest.u8[1],
e->nexthop.u8[0], e->nexthop.u8[1],
e->cost);
if(e->time != e->time_last_decay) {
/* Do not decay a route too often - not more than once per second. */
e->time_last_decay = e->time;
e->decay++;
if(e->decay >= DECAY_THRESHOLD) {
PRINTF("route_decay: removing entry to %d.%d with nexthop %d.%d and cost %d\n",
e->dest.u8[0], e->dest.u8[1],
e->nexthop.u8[0], e->nexthop.u8[1],
e->cost);
route_remove(e);
}
}
}
/*---------------------------------------------------------------------------*/
void
route_remove(struct route_entry *e)
{
list_remove(route_table, e);
memb_free(&route_mem, e);
}
/*---------------------------------------------------------------------------*/
void
route_flush_all(void)
{
struct route_entry *e;
while(1) {
e = list_pop(route_table);
if(e != NULL) {
memb_free(&route_mem, e);
} else {
break;
}
}
}
/*---------------------------------------------------------------------------*/
void
route_set_lifetime(int seconds)
{
max_time = seconds;
}
/*---------------------------------------------------------------------------*/
int
route_num(void)
{
struct route_entry *e;
int i = 0;
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for(e = list_head(route_table); e != NULL; e = list_item_next(e)) {
i++;
}
return i;
}
/*---------------------------------------------------------------------------*/
struct route_entry *
route_get(int num)
{
struct route_entry *e;
int i = 0;
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for(e = list_head(route_table); e != NULL; e = list_item_next(e)) {
if(i == num) {
return e;
}
i++;
}
return NULL;
}
/*---------------------------------------------------------------------------*/
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/** @} */