116 lines
3.8 KiB
C
116 lines
3.8 KiB
C
/*
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* Copyright (c) 2014, Hasso-Plattner-Institut.
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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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/**
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* \file
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* Protects against replay attacks by comparing with the last
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* unicast or broadcast frame counter of the sender.
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* \author
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* Konrad Krentz <konrad.krentz@gmail.com>
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*/
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/**
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* \addtogroup csma
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* @{
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*/
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#include "net/mac/csma/anti-replay.h"
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#include "net/packetbuf.h"
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#include "net/mac/llsec802154.h"
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#if LLSEC802154_USES_FRAME_COUNTER
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/* This node's current frame counter value */
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static uint32_t counter;
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/*---------------------------------------------------------------------------*/
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void
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anti_replay_set_counter(void)
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{
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frame802154_frame_counter_t reordered_counter;
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++counter;
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reordered_counter.u32 = LLSEC802154_HTONL(counter);
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packetbuf_set_attr(PACKETBUF_ATTR_FRAME_COUNTER_BYTES_0_1, reordered_counter.u16[0]);
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packetbuf_set_attr(PACKETBUF_ATTR_FRAME_COUNTER_BYTES_2_3, reordered_counter.u16[1]);
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}
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/*---------------------------------------------------------------------------*/
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uint32_t
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anti_replay_get_counter(void)
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{
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frame802154_frame_counter_t disordered_counter;
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disordered_counter.u16[0] = packetbuf_attr(PACKETBUF_ATTR_FRAME_COUNTER_BYTES_0_1);
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disordered_counter.u16[1] = packetbuf_attr(PACKETBUF_ATTR_FRAME_COUNTER_BYTES_2_3);
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return LLSEC802154_HTONL(disordered_counter.u32);
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}
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/*---------------------------------------------------------------------------*/
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void
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anti_replay_init_info(struct anti_replay_info *info)
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{
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info->last_broadcast_counter
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= info->last_unicast_counter
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= anti_replay_get_counter();
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}
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/*---------------------------------------------------------------------------*/
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int
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anti_replay_was_replayed(struct anti_replay_info *info)
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{
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uint32_t received_counter;
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received_counter = anti_replay_get_counter();
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if(packetbuf_holds_broadcast()) {
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/* broadcast */
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if(received_counter <= info->last_broadcast_counter) {
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return 1;
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} else {
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info->last_broadcast_counter = received_counter;
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return 0;
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}
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} else {
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/* unicast */
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if(received_counter <= info->last_unicast_counter) {
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return 1;
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} else {
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info->last_unicast_counter = received_counter;
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return 0;
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}
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}
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}
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/*---------------------------------------------------------------------------*/
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#endif /* LLSEC802154_USES_FRAME_COUNTER */
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/** @} */
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