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contiki/core/net/ipv6/uip-ds6-nbr.c

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/*
* 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.
*
*
*/
/**
* \addtogroup uip6
* @{
*/
/**
* \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/link-stats.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)
{
link_stats_init();
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, nbr_table_reason_t reason,
void *data)
{
uip_ds6_nbr_t *nbr = nbr_table_add_lladdr(ds6_neighbors, (linkaddr_t*)lladdr
, reason, data);
if(nbr) {
uip_ipaddr_copy(&nbr->ipaddr, ipaddr);
#if UIP_ND6_SEND_RA || !UIP_CONF_ROUTER
nbr->isrouter = isrouter;
#endif /* UIP_ND6_SEND_RA || !UIP_CONF_ROUTER */
nbr->state = state;
#if UIP_CONF_IPV6_QUEUE_PKT
uip_packetqueue_new(&nbr->packethandle);
#endif /* UIP_CONF_IPV6_QUEUE_PKT */
#if UIP_ND6_SEND_NS
if(nbr->state == NBR_REACHABLE) {
stimer_set(&nbr->reachable, UIP_ND6_REACHABLE_TIME / 1000);
} else {
/* We set the timer in expired state */
stimer_set(&nbr->reachable, 0);
}
stimer_set(&nbr->sendns, 0);
nbr->nscount = 0;
#endif /* UIP_ND6_SEND_NS */
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;
}
}
/*---------------------------------------------------------------------------*/
int
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);
return nbr_table_remove(ds6_neighbors, nbr);
}
return 0;
}
/*---------------------------------------------------------------------------*/
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;
}
/* Update neighbor link statistics */
link_stats_packet_sent(dest, status, numtx);
/* Call upper-layer callback (e.g. RPL) */
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 */
}
#if UIP_ND6_SEND_NS
/*---------------------------------------------------------------------------*/
/** Periodic processing on neighbors */
void
uip_ds6_neighbor_periodic(void)
{
uip_ds6_nbr_t *nbr = nbr_table_head(ds6_neighbors);
while(nbr != NULL) {
switch(nbr->state) {
case NBR_REACHABLE:
if(stimer_expired(&nbr->reachable)) {
#if UIP_CONF_IPV6_RPL
/* when a neighbor leave its REACHABLE state and is a default router,
instead of going to STALE state it enters DELAY state in order to
force a NUD on it. Otherwise, if there is no upward traffic, the
node never knows if the default router is still reachable. This
mimics the 6LoWPAN-ND behavior.
*/
if(uip_ds6_defrt_lookup(&nbr->ipaddr) != NULL) {
PRINTF("REACHABLE: defrt moving to DELAY (");
PRINT6ADDR(&nbr->ipaddr);
PRINTF(")\n");
nbr->state = NBR_DELAY;
stimer_set(&nbr->reachable, UIP_ND6_DELAY_FIRST_PROBE_TIME);
nbr->nscount = 0;
} else {
PRINTF("REACHABLE: moving to STALE (");
PRINT6ADDR(&nbr->ipaddr);
PRINTF(")\n");
nbr->state = NBR_STALE;
}
#else /* UIP_CONF_IPV6_RPL */
PRINTF("REACHABLE: moving to STALE (");
PRINT6ADDR(&nbr->ipaddr);
PRINTF(")\n");
nbr->state = NBR_STALE;
#endif /* UIP_CONF_IPV6_RPL */
}
break;
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;
default:
break;
}
nbr = nbr_table_next(ds6_neighbors, nbr);
}
}
/*---------------------------------------------------------------------------*/
void
uip_ds6_nbr_refresh_reachable_state(const uip_ipaddr_t *ipaddr)
{
uip_ds6_nbr_t *nbr;
nbr = uip_ds6_nbr_lookup(ipaddr);
if(nbr != NULL) {
nbr->state = NBR_REACHABLE;
nbr->nscount = 0;
stimer_set(&nbr->reachable, UIP_ND6_REACHABLE_TIME / 1000);
}
}
/*---------------------------------------------------------------------------*/
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;
}
#endif /* UIP_ND6_SEND_NS */
/*---------------------------------------------------------------------------*/
/** @} */
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