contiki/core/net/llsec/anti-replay.c

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2014-04-27 09:20:03 +00:00
/**
* \addtogroup llsec802154
* @{
*/
/*
* Copyright (c) 2014, Hasso-Plattner-Institut.
* 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
* Protects against replay attacks by comparing with the last
* unicast or broadcast frame counter of the sender.
* \author
* Konrad Krentz <konrad.krentz@gmail.com>
*/
#include "net/llsec/anti-replay.h"
#include "net/packetbuf.h"
/* This node's current frame counter value */
static uint32_t counter;
/*---------------------------------------------------------------------------*/
void
anti_replay_set_counter(void)
{
frame802154_frame_counter_t reordered_counter;
reordered_counter.u32 = LLSEC802154_HTONL(++counter);
packetbuf_set_attr(PACKETBUF_ATTR_FRAME_COUNTER_BYTES_0_1, reordered_counter.u16[0]);
packetbuf_set_attr(PACKETBUF_ATTR_FRAME_COUNTER_BYTES_2_3, reordered_counter.u16[1]);
}
/*---------------------------------------------------------------------------*/
uint32_t
anti_replay_get_counter(void)
{
frame802154_frame_counter_t disordered_counter;
disordered_counter.u16[0] = packetbuf_attr(PACKETBUF_ATTR_FRAME_COUNTER_BYTES_0_1);
disordered_counter.u16[1] = packetbuf_attr(PACKETBUF_ATTR_FRAME_COUNTER_BYTES_2_3);
return LLSEC802154_HTONL(disordered_counter.u32);
}
/*---------------------------------------------------------------------------*/
void
anti_replay_init_info(struct anti_replay_info *info)
{
info->last_broadcast_counter
= info->last_unicast_counter
= anti_replay_get_counter();
}
/*---------------------------------------------------------------------------*/
int
anti_replay_was_replayed(struct anti_replay_info *info)
{
uint32_t received_counter;
received_counter = anti_replay_get_counter();
if(linkaddr_cmp(packetbuf_addr(PACKETBUF_ADDR_RECEIVER), &linkaddr_null)) {
/* broadcast */
if(received_counter <= info->last_broadcast_counter) {
return 1;
} else {
info->last_broadcast_counter = received_counter;
return 0;
}
} else {
/* unicast */
if(received_counter <= info->last_unicast_counter) {
return 1;
} else {
info->last_unicast_counter = received_counter;
return 0;
}
}
}
/*---------------------------------------------------------------------------*/
/** @} */