contiki/core/net/mac/mac-sequence.c

125 lines
4.2 KiB
C

/*
* Copyright (c) 2010, Swedish Institute of Computer Science.
* All rights reserved.
*
* Copyright (c) 2013, ADVANSEE - http://www.advansee.com/
* Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
* 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
* MAC sequence numbers management
* \author
* Adam Dunkels <adam@sics.se>
* Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
*/
#include <string.h>
#include "contiki-net.h"
#include "net/mac/mac-sequence.h"
#include "net/packetbuf.h"
#include "net/rime/rime.h"
struct seqno {
linkaddr_t sender;
clock_time_t timestamp;
uint8_t seqno;
};
#ifdef NETSTACK_CONF_MAC_SEQNO_MAX_AGE
#define SEQNO_MAX_AGE NETSTACK_CONF_MAC_SEQNO_MAX_AGE
#else /* NETSTACK_CONF_MAC_SEQNO_MAX_AGE */
#define SEQNO_MAX_AGE (20 * CLOCK_SECOND)
#endif /* NETSTACK_CONF_MAC_SEQNO_MAX_AGE */
#ifdef NETSTACK_CONF_MAC_SEQNO_HISTORY
#define MAX_SEQNOS NETSTACK_CONF_MAC_SEQNO_HISTORY
#else /* NETSTACK_CONF_MAC_SEQNO_HISTORY */
#define MAX_SEQNOS 16
#endif /* NETSTACK_CONF_MAC_SEQNO_HISTORY */
static struct seqno received_seqnos[MAX_SEQNOS];
/*---------------------------------------------------------------------------*/
int
mac_sequence_is_duplicate(void)
{
int i;
clock_time_t now = clock_time();
/*
* Check for duplicate packet by comparing the sequence number of the incoming
* packet with the last few ones we saw.
*/
for(i = 0; i < MAX_SEQNOS; ++i) {
if(linkaddr_cmp(packetbuf_addr(PACKETBUF_ADDR_SENDER),
&received_seqnos[i].sender)) {
if(packetbuf_attr(PACKETBUF_ATTR_MAC_SEQNO) == received_seqnos[i].seqno) {
#if SEQNO_MAX_AGE > 0
if(now - received_seqnos[i].timestamp <= SEQNO_MAX_AGE) {
/* Duplicate packet. */
return 1;
}
#else /* SEQNO_MAX_AGE > 0 */
return 1;
#endif /* SEQNO_MAX_AGE > 0 */
}
break;
}
}
return 0;
}
/*---------------------------------------------------------------------------*/
void
mac_sequence_register_seqno(void)
{
int i, j;
/* Locate possible previous sequence number for this address. */
for(i = 0; i < MAX_SEQNOS; ++i) {
if(linkaddr_cmp(packetbuf_addr(PACKETBUF_ADDR_SENDER),
&received_seqnos[i].sender)) {
i++;
break;
}
}
/* Keep the last sequence number for each address as per 802.15.4e. */
for(j = i - 1; j > 0; --j) {
memcpy(&received_seqnos[j], &received_seqnos[j - 1], sizeof(struct seqno));
}
received_seqnos[0].seqno = packetbuf_attr(PACKETBUF_ATTR_MAC_SEQNO);
received_seqnos[0].timestamp = clock_time();
linkaddr_copy(&received_seqnos[0].sender,
packetbuf_addr(PACKETBUF_ADDR_SENDER));
}
/*---------------------------------------------------------------------------*/