contiki/core/net/ip/uip-nameserver.c

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/**
* \addtogroup uip6
* @{
*/
/**
* \file
* uIP Name Server interface
* \author Víctor Ariño <victor.arino@tado.com>
*/
/*
* Copyright (c) 2014, tado° GmbH.
* 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.
*
*/
#include "contiki.h"
#include "contiki-net.h"
#include "lib/list.h"
#include "lib/memb.h"
#include <string.h>
/** \brief Nameserver record */
typedef struct uip_nameserver_record {
struct uip_nameserver_record *next;
uip_ipaddr_t ip;
uint32_t added;
uint32_t lifetime;
} uip_nameserver_record;
#if UIP_NAMESERVER_POOL_SIZE > 1
/** \brief Initialization flag */
static uint8_t initialized = 0;
#endif /* UIP_NAMESERVER_POOL_SIZE > 1 */
/** \name List and memory block
* @{
*/
#if UIP_NAMESERVER_POOL_SIZE > 1
LIST(dns);
MEMB(dnsmemb, uip_nameserver_record, UIP_NAMESERVER_POOL_SIZE);
#else /* UIP_NAMESERVER_POOL_SIZE > 1 */
static uip_ipaddr_t serveraddr;
static uint32_t serverlifetime;
#endif /* UIP_NAMESERVER_POOL_SIZE > 1 */
/** @} */
/** \brief Expiration time in seconds */
#define DNS_EXPIRATION(r) \
(((UIP_NAMESERVER_INFINITE_LIFETIME - r->added) <= r->lifetime) ? \
UIP_NAMESERVER_INFINITE_LIFETIME : r->added + r->lifetime)
/*----------------------------------------------------------------------------*/
/**
* Initialize the module variables
*/
#if UIP_NAMESERVER_POOL_SIZE > 1
static CC_INLINE void
init(void)
{
list_init(dns);
memb_init(&dnsmemb);
initialized = 1;
}
#endif /* UIP_NAMESERVER_POOL_SIZE > 1 */
/*----------------------------------------------------------------------------*/
void
uip_nameserver_update(const uip_ipaddr_t *nameserver, uint32_t lifetime)
{
#if UIP_NAMESERVER_POOL_SIZE > 1
register uip_nameserver_record *e;
if(initialized == 0) {
init();
}
for(e = list_head(dns); e != NULL; e = list_item_next(e)) {
if(uip_ipaddr_cmp(&e->ip, nameserver)) {
break;
/* RFC6106: In case there's no more space, the new servers should replace
* the the eldest ones */
}
}
if(e == NULL) {
if((e = memb_alloc(&dnsmemb)) != NULL) {
list_add(dns, e);
} else {
uip_nameserver_record *p;
for(e = list_head(dns), p = list_head(dns); p != NULL;
p = list_item_next(p)) {
if(DNS_EXPIRATION(p) < DNS_EXPIRATION(e)) {
e = p;
}
}
}
}
/* RFC6106: In case the entry is existing the expiration time must be
* updated. Otherwise, new entries are added. */
if(e != NULL) {
if(lifetime == 0) {
memb_free(&dnsmemb, e);
list_remove(dns, e);
} else {
e->added = clock_seconds();
e->lifetime = lifetime;
uip_ipaddr_copy(&e->ip, nameserver);
}
}
#else /* UIP_NAMESERVER_POOL_SIZE > 1 */
uip_ipaddr_copy(&serveraddr, nameserver);
serverlifetime = lifetime;
#endif /* UIP_NAMESERVER_POOL_SIZE > 1 */
}
/*----------------------------------------------------------------------------*/
#if UIP_NAMESERVER_POOL_SIZE > 1
/**
* Purge expired records
*/
static void
purge(void)
{
register uip_nameserver_record *e = NULL;
uint32_t time = clock_seconds();
for(e = list_head(dns); e != NULL; e = list_item_next(e)) {
if(DNS_EXPIRATION(e) < time) {
list_remove(dns, e);
memb_free(&dnsmemb, e);
e = list_head(dns);
}
}
}
#endif /* UIP_NAMESERVER_POOL_SIZE > 1 */
/*----------------------------------------------------------------------------*/
uip_ipaddr_t *
uip_nameserver_get(uint8_t num)
{
#if UIP_NAMESERVER_POOL_SIZE > 1
uint8_t i;
uip_nameserver_record *e = NULL;
if(initialized == 0) {
return NULL;
}
purge();
for(i = 1, e = list_head(dns); e != NULL && i <= num;
i++, e = list_item_next(e)) {
}
if(e != NULL) {
return &e->ip;
}
return NULL;
#else /* UIP_NAMESERVER_POOL_SIZE > 1 */
if(num > 0) {
return NULL;
}
return &serveraddr;
#endif /* UIP_NAMESERVER_POOL_SIZE > 1 */
}
/*----------------------------------------------------------------------------*/
uint32_t
uip_nameserver_next_expiration(void)
{
#if UIP_NAMESERVER_POOL_SIZE > 1
register uip_nameserver_record *e = NULL;
uint32_t exp = UIP_NAMESERVER_INFINITE_LIFETIME;
uint32_t t;
if(initialized == 0 || list_length(dns) == 0) {
return 0;
}
purge();
for(e = list_head(dns); e != NULL; e = list_item_next(e)) {
t = DNS_EXPIRATION(e);
if(t < exp) {
exp = t;
}
}
return exp;
#else /* UIP_NAMESERVER_POOL_SIZE > 1 */
return serverlifetime;
#endif /* UIP_NAMESERVER_POOL_SIZE > 1 */
}
/*----------------------------------------------------------------------------*/
uint16_t
uip_nameserver_count(void)
{
#if UIP_NAMESERVER_POOL_SIZE > 1
if(initialized == 0) {
return 0;
}
return list_length(dns);
#else /* UIP_NAMESERVER_POOL_SIZE > 1 */
#if NETSTACK_CONF_WITH_IPV6
if(uip_is_addr_unspecified(&serveraddr)) {
#else /* NETSTACK_CONF_WITH_IPV6 */
if(uip_ipaddr_cmp(&serveraddr, &uip_all_zeroes_addr)) {
#endif /* NETSTACK_CONF_WITH_IPV6 */
return 0;
} else {
return 1;
}
#endif /* UIP_NAMESERVER_POOL_SIZE > 1 */
}
/*----------------------------------------------------------------------------*/
/** @} */