197 lines
5.1 KiB
C
197 lines
5.1 KiB
C
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/**
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* \addtogroup uip6
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* @{
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*/
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/**
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* \file
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* uIP Name Server interface
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* \author Víctor Ariño <victor.arino@tado.com>
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*/
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/*
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* Copyright (c) 2014, tado° GmbH.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the Institute nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* This file is part of the Contiki operating system.
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*
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*/
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#include "contiki.h"
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#include "contiki-net.h"
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#include "lib/list.h"
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#include "lib/memb.h"
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#include <string.h>
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/** \brief Nameserver record */
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typedef struct uip_namserver_record {
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struct uip_namserver_record *next;
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uip_ipaddr_t ip;
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uint32_t added;
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uint32_t lifetime;
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} uip_namserver_record;
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/** \brief Initialization flag */
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static uint8_t initialized = 0;
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/** \name List and memory block
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* @{
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*/
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LIST(dns);
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MEMB(dnsmemb, uip_namserver_record, UIP_NAMESERVER_POOL_SIZE);
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/** @} */
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/** \brief Expiration time in seconds */
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#define DNS_EXPIRATION(r) \
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(((UIP_NAMESERVER_INFINITE_LIFETIME - r->added) <= r->lifetime) ? \
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UIP_NAMESERVER_INFINITE_LIFETIME : r->added + r->lifetime)
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/*----------------------------------------------------------------------------*/
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/**
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* Initialize the module variables
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*/
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static void inline
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init(void)
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{
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list_init(dns);
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memb_init(&dnsmemb);
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initialized = 1;
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}
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/*----------------------------------------------------------------------------*/
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void
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uip_nameserver_update(uip_ipaddr_t *nameserver, uint32_t lifetime)
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{
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if(initialized == 0) {
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init();
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}
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register uip_namserver_record *e;
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for(e = list_head(dns); e != NULL; e = list_item_next(e)) {
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if(uip_ipaddr_cmp(&e->ip, nameserver)) {
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break;
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}
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}
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/* RFC6106: In case there's no more space, the new servers should replace
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* the the eldest ones */
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if(e == NULL) {
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if((e = memb_alloc(&dnsmemb)) != NULL) {
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list_add(dns, e);
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} else {
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uip_namserver_record *p;
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for(e = list_head(dns), p = list_head(dns); p != NULL;
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p = list_item_next(p)) {
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if(DNS_EXPIRATION(p) < DNS_EXPIRATION(e)) {
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e = p;
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}
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}
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}
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}
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/* RFC6106: In case the entry is existing the expiration time must be
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* updated. Otherwise, new entries are added. */
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if(e != NULL) {
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if(lifetime == 0) {
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memb_free(&dnsmemb, e);
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list_remove(dns, e);
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} else {
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e->added = clock_seconds();
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e->lifetime = lifetime;
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uip_ipaddr_copy(&e->ip, nameserver);
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}
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}
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}
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/*----------------------------------------------------------------------------*/
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/**
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* Purge expired records
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*/
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static void
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purge(void)
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{
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register uip_namserver_record *e = NULL;
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uint32_t time = clock_seconds();
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for(e = list_head(dns); e != NULL; e = list_item_next(e)) {
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if(DNS_EXPIRATION(e) < time) {
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list_remove(dns, e);
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memb_free(&dnsmemb, e);
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e = list_head(dns);
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}
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}
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}
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/*----------------------------------------------------------------------------*/
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uip_ipaddr_t *
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uip_nameserver_get(uint8_t num)
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{
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uint8_t i;
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uip_namserver_record *e = NULL;
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if(initialized == 0) {
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return NULL;
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}
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purge();
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for(i = 1, e = list_head(dns); e != NULL && i <= num;
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i++, e = list_item_next(e));
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if(e != NULL) {
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return &e->ip;
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}
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return NULL;
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}
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/*----------------------------------------------------------------------------*/
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uint32_t
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uip_nameserver_next_expiration(void)
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{
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register uip_namserver_record *e = NULL;
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uint32_t exp = UIP_NAMESERVER_INFINITE_LIFETIME;
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uint32_t t;
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if(initialized == 0 || list_length(dns) == 0) {
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return 0;
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}
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purge();
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for(e = list_head(dns); e != NULL; e = list_item_next(e)) {
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t = DNS_EXPIRATION(e);
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if(t < exp) {
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exp = t;
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}
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}
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return exp;
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}
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/*----------------------------------------------------------------------------*/
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uint16_t
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uip_nameserver_count(void)
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{
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if(initialized == 0) {
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return 0;
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}
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return list_length(dns);
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}
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/*----------------------------------------------------------------------------*/
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/** @} */
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