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osd-contiki/core/net/ipv6/uip-ds6-nbr.c
Víctor Ariño 0f394b220b uip-ds6-nbr: consider reachable node if LL-NUD 
The reachable state might also be considered to keep the reachable
state since we are already not standard complaint. This reduces the
nbr discovery messages if nodes talk to each other periodically.
2014-12-01 17:06:14 +01:00

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/**
* \addtogroup uip6
* @{
*/
/*
* Copyright (c) 2013, 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.
*
*
*/
/**
* \file
* IPv6 Neighbor cache (link-layer/IPv6 address mapping)
* \author Mathilde Durvy <mdurvy@cisco.com>
* \author Julien Abeille <jabeille@cisco.com>
* \author Simon Duquennoy <simonduq@sics.se>
*
*/
#include <string.h>
#include <stdlib.h>
#include <stddef.h>
#include "lib/list.h"
#include "net/linkaddr.h"
#include "net/packetbuf.h"
#include "net/ipv6/uip-ds6-nbr.h"
#define DEBUG DEBUG_NONE
#include "net/ip/uip-debug.h"
#ifdef UIP_CONF_DS6_NEIGHBOR_STATE_CHANGED
#define NEIGHBOR_STATE_CHANGED(n) UIP_CONF_DS6_NEIGHBOR_STATE_CHANGED(n)
void NEIGHBOR_STATE_CHANGED(uip_ds6_nbr_t *n);
#else
#define NEIGHBOR_STATE_CHANGED(n)
#endif /* UIP_DS6_CONF_NEIGHBOR_STATE_CHANGED */
#ifdef UIP_CONF_DS6_LINK_NEIGHBOR_CALLBACK
#define LINK_NEIGHBOR_CALLBACK(addr, status, numtx) UIP_CONF_DS6_LINK_NEIGHBOR_CALLBACK(addr, status, numtx)
void LINK_NEIGHBOR_CALLBACK(const linkaddr_t *addr, int status, int numtx);
#else
#define LINK_NEIGHBOR_CALLBACK(addr, status, numtx)
#endif /* UIP_CONF_DS6_LINK_NEIGHBOR_CALLBACK */
NBR_TABLE_GLOBAL(uip_ds6_nbr_t, ds6_neighbors);
/*---------------------------------------------------------------------------*/
void
uip_ds6_neighbors_init(void)
{
nbr_table_register(ds6_neighbors, (nbr_table_callback *)uip_ds6_nbr_rm);
}
/*---------------------------------------------------------------------------*/
uip_ds6_nbr_t *
uip_ds6_nbr_add(const uip_ipaddr_t *ipaddr, const uip_lladdr_t *lladdr,
uint8_t isrouter, uint8_t state)
{
uip_ds6_nbr_t *nbr = nbr_table_add_lladdr(ds6_neighbors, (linkaddr_t*)lladdr);
if(nbr) {
uip_ipaddr_copy(&nbr->ipaddr, ipaddr);
nbr->isrouter = isrouter;
nbr->state = state;
#if UIP_CONF_IPV6_QUEUE_PKT
uip_packetqueue_new(&nbr->packethandle);
#endif /* UIP_CONF_IPV6_QUEUE_PKT */
/* timers are set separately, for now we put them in expired state */
stimer_set(&nbr->reachable, 0);
stimer_set(&nbr->sendns, 0);
nbr->nscount = 0;
PRINTF("Adding neighbor with ip addr ");
PRINT6ADDR(ipaddr);
PRINTF(" link addr ");
PRINTLLADDR(lladdr);
PRINTF(" state %u\n", state);
NEIGHBOR_STATE_CHANGED(nbr);
return nbr;
} else {
PRINTF("uip_ds6_nbr_add drop ip addr ");
PRINT6ADDR(ipaddr);
PRINTF(" link addr (%p) ", lladdr);
PRINTLLADDR(lladdr);
PRINTF(" state %u\n", state);
return NULL;
}
}
/*---------------------------------------------------------------------------*/
void
uip_ds6_nbr_rm(uip_ds6_nbr_t *nbr)
{
if(nbr != NULL) {
#if UIP_CONF_IPV6_QUEUE_PKT
uip_packetqueue_free(&nbr->packethandle);
#endif /* UIP_CONF_IPV6_QUEUE_PKT */
NEIGHBOR_STATE_CHANGED(nbr);
nbr_table_remove(ds6_neighbors, nbr);
}
return;
}
/*---------------------------------------------------------------------------*/
const uip_ipaddr_t *
uip_ds6_nbr_get_ipaddr(const uip_ds6_nbr_t *nbr)
{
return (nbr != NULL) ? &nbr->ipaddr : NULL;
}
/*---------------------------------------------------------------------------*/
const uip_lladdr_t *
uip_ds6_nbr_get_ll(const uip_ds6_nbr_t *nbr)
{
return (const uip_lladdr_t *)nbr_table_get_lladdr(ds6_neighbors, nbr);
}
/*---------------------------------------------------------------------------*/
int
uip_ds6_nbr_num(void)
{
uip_ds6_nbr_t *nbr;
int num;
num = 0;
for(nbr = nbr_table_head(ds6_neighbors);
nbr != NULL;
nbr = nbr_table_next(ds6_neighbors, nbr)) {
num++;
}
return num;
}
/*---------------------------------------------------------------------------*/
uip_ds6_nbr_t *
uip_ds6_nbr_lookup(const uip_ipaddr_t *ipaddr)
{
uip_ds6_nbr_t *nbr = nbr_table_head(ds6_neighbors);
if(ipaddr != NULL) {
while(nbr != NULL) {
if(uip_ipaddr_cmp(&nbr->ipaddr, ipaddr)) {
return nbr;
}
nbr = nbr_table_next(ds6_neighbors, nbr);
}
}
return NULL;
}
/*---------------------------------------------------------------------------*/
uip_ds6_nbr_t *
uip_ds6_nbr_ll_lookup(const uip_lladdr_t *lladdr)
{
return nbr_table_get_from_lladdr(ds6_neighbors, (linkaddr_t*)lladdr);
}
/*---------------------------------------------------------------------------*/
uip_ipaddr_t *
uip_ds6_nbr_ipaddr_from_lladdr(const uip_lladdr_t *lladdr)
{
uip_ds6_nbr_t *nbr = uip_ds6_nbr_ll_lookup(lladdr);
return nbr ? &nbr->ipaddr : NULL;
}
/*---------------------------------------------------------------------------*/
const uip_lladdr_t *
uip_ds6_nbr_lladdr_from_ipaddr(const uip_ipaddr_t *ipaddr)
{
uip_ds6_nbr_t *nbr = uip_ds6_nbr_lookup(ipaddr);
return nbr ? uip_ds6_nbr_get_ll(nbr) : NULL;
}
/*---------------------------------------------------------------------------*/
void
uip_ds6_link_neighbor_callback(int status, int numtx)
{
const linkaddr_t *dest = packetbuf_addr(PACKETBUF_ADDR_RECEIVER);
if(linkaddr_cmp(dest, &linkaddr_null)) {
return;
}
LINK_NEIGHBOR_CALLBACK(dest, status, numtx);
#if UIP_DS6_LL_NUD
/* From RFC4861, page 72, last paragraph of section 7.3.3:
*
* "In some cases, link-specific information may indicate that a path to
* a neighbor has failed (e.g., the resetting of a virtual circuit). In
* such cases, link-specific information may be used to purge Neighbor
* Cache entries before the Neighbor Unreachability Detection would do
* so. However, link-specific information MUST NOT be used to confirm
* the reachability of a neighbor; such information does not provide
* end-to-end confirmation between neighboring IP layers."
*
* However, we assume that receiving a link layer ack ensures the delivery
* of the transmitted packed to the IP stack of the neighbour. This is a
* fair assumption and allows battery powered nodes save some battery by
* not re-testing the state of a neighbour periodically if it
* acknowledges link packets. */
if(status == MAC_TX_OK) {
uip_ds6_nbr_t *nbr;
nbr = uip_ds6_nbr_ll_lookup((uip_lladdr_t *)dest);
if(nbr != NULL && nbr->state != NBR_INCOMPLETE) {
nbr->state = NBR_REACHABLE;
stimer_set(&nbr->reachable, UIP_ND6_REACHABLE_TIME / 1000);
PRINTF("uip-ds6-neighbor : received a link layer ACK : ");
PRINTLLADDR((uip_lladdr_t *)dest);
PRINTF(" is reachable.\n");
}
}
#endif /* UIP_DS6_LL_NUD */
}
/*---------------------------------------------------------------------------*/
void
uip_ds6_neighbor_periodic(void)
{
/* Periodic processing on neighbors */
uip_ds6_nbr_t *nbr = nbr_table_head(ds6_neighbors);
while(nbr != NULL) {
switch(nbr->state) {
case NBR_REACHABLE:
if(stimer_expired(&nbr->reachable)) {
PRINTF("REACHABLE: moving to STALE (");
PRINT6ADDR(&nbr->ipaddr);
PRINTF(")\n");
nbr->state = NBR_STALE;
}
break;
#if UIP_ND6_SEND_NA
case NBR_INCOMPLETE:
if(nbr->nscount >= UIP_ND6_MAX_MULTICAST_SOLICIT) {
uip_ds6_nbr_rm(nbr);
} else if(stimer_expired(&nbr->sendns) && (uip_len == 0)) {
nbr->nscount++;
PRINTF("NBR_INCOMPLETE: NS %u\n", nbr->nscount);
uip_nd6_ns_output(NULL, NULL, &nbr->ipaddr);
stimer_set(&nbr->sendns, uip_ds6_if.retrans_timer / 1000);
}
break;
case NBR_DELAY:
if(stimer_expired(&nbr->reachable)) {
nbr->state = NBR_PROBE;
nbr->nscount = 0;
PRINTF("DELAY: moving to PROBE\n");
stimer_set(&nbr->sendns, 0);
}
break;
case NBR_PROBE:
if(nbr->nscount >= UIP_ND6_MAX_UNICAST_SOLICIT) {
uip_ds6_defrt_t *locdefrt;
PRINTF("PROBE END\n");
if((locdefrt = uip_ds6_defrt_lookup(&nbr->ipaddr)) != NULL) {
if (!locdefrt->isinfinite) {
uip_ds6_defrt_rm(locdefrt);
}
}
uip_ds6_nbr_rm(nbr);
} else if(stimer_expired(&nbr->sendns) && (uip_len == 0)) {
nbr->nscount++;
PRINTF("PROBE: NS %u\n", nbr->nscount);
uip_nd6_ns_output(NULL, &nbr->ipaddr, &nbr->ipaddr);
stimer_set(&nbr->sendns, uip_ds6_if.retrans_timer / 1000);
}
break;
#endif /* UIP_ND6_SEND_NA */
default:
break;
}
nbr = nbr_table_next(ds6_neighbors, nbr);
}
}
/*---------------------------------------------------------------------------*/
uip_ds6_nbr_t *
uip_ds6_get_least_lifetime_neighbor(void)
{
uip_ds6_nbr_t *nbr = nbr_table_head(ds6_neighbors);
uip_ds6_nbr_t *nbr_expiring = NULL;
while(nbr != NULL) {
if(nbr_expiring != NULL) {
clock_time_t curr = stimer_remaining(&nbr->reachable);
if(curr < stimer_remaining(&nbr->reachable)) {
nbr_expiring = nbr;
}
} else {
nbr_expiring = nbr;
}
nbr = nbr_table_next(ds6_neighbors, nbr);
}
return nbr_expiring;
}
/*---------------------------------------------------------------------------*/
/** @} */
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