Contiki-NG
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mac-sequence.c
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1/*
2 * Copyright (c) 2010, Swedish Institute of Computer Science.
3 * All rights reserved.
4 *
5 * Copyright (c) 2013, ADVANSEE - http://www.advansee.com/
6 * Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. Neither the name of the Institute nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * This file is part of the Contiki operating system.
34 *
35 */
36
37/**
38 * \file
39 * MAC sequence numbers management
40 * \author
41 * Adam Dunkels <adam@sics.se>
42 * Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
43 */
44
45#include <string.h>
46
47#include "contiki-net.h"
48#include "lib/random.h"
50#include "net/packetbuf.h"
51
52struct seqno {
53 linkaddr_t sender;
54 clock_time_t timestamp;
55 uint8_t seqno;
56};
57
58#ifdef NETSTACK_CONF_MAC_SEQNO_MAX_AGE
59#define SEQNO_MAX_AGE NETSTACK_CONF_MAC_SEQNO_MAX_AGE
60#else /* NETSTACK_CONF_MAC_SEQNO_MAX_AGE */
61#define SEQNO_MAX_AGE (20 * CLOCK_SECOND)
62#endif /* NETSTACK_CONF_MAC_SEQNO_MAX_AGE */
63
64#ifdef NETSTACK_CONF_MAC_SEQNO_HISTORY
65#define MAX_SEQNOS NETSTACK_CONF_MAC_SEQNO_HISTORY
66#else /* NETSTACK_CONF_MAC_SEQNO_HISTORY */
67#define MAX_SEQNOS 16
68#endif /* NETSTACK_CONF_MAC_SEQNO_HISTORY */
69static struct seqno received_seqnos[MAX_SEQNOS];
70
71static uint8_t mac_dsn;
72
73/*---------------------------------------------------------------------------*/
74void
76{
77 mac_dsn = random_rand();
78}
79/*---------------------------------------------------------------------------*/
80void
82{
83 packetbuf_set_attr(PACKETBUF_ATTR_MAC_SEQNO, mac_dsn++);
84}
85/*---------------------------------------------------------------------------*/
86int
88{
89 int i;
90 clock_time_t now = clock_time();
91
92 /*
93 * Check for duplicate packet by comparing the sequence number of the incoming
94 * packet with the last few ones we saw.
95 */
96 for(i = 0; i < MAX_SEQNOS; ++i) {
97 if(linkaddr_cmp(packetbuf_addr(PACKETBUF_ADDR_SENDER),
98 &received_seqnos[i].sender)) {
99 if(packetbuf_attr(PACKETBUF_ATTR_MAC_SEQNO) == received_seqnos[i].seqno) {
100#if SEQNO_MAX_AGE > 0
101 if(now - received_seqnos[i].timestamp <= SEQNO_MAX_AGE) {
102 /* Duplicate packet. */
103 return 1;
104 }
105#else /* SEQNO_MAX_AGE > 0 */
106 return 1;
107#endif /* SEQNO_MAX_AGE > 0 */
108 }
109 break;
110 }
111 }
112 return 0;
113}
114/*---------------------------------------------------------------------------*/
115void
117{
118 int i, j;
119
120 /* Locate possible previous sequence number for this address. */
121 for(i = 0; i < MAX_SEQNOS; ++i) {
122 if(linkaddr_cmp(packetbuf_addr(PACKETBUF_ADDR_SENDER),
123 &received_seqnos[i].sender)) {
124 i++;
125 break;
126 }
127 }
128
129 /* Keep the last sequence number for each address as per 802.15.4e. */
130 for(j = i - 1; j > 0; --j) {
131 memcpy(&received_seqnos[j], &received_seqnos[j - 1], sizeof(struct seqno));
132 }
133 received_seqnos[0].seqno = packetbuf_attr(PACKETBUF_ATTR_MAC_SEQNO);
134 received_seqnos[0].timestamp = clock_time();
135 linkaddr_copy(&received_seqnos[0].sender,
136 packetbuf_addr(PACKETBUF_ADDR_SENDER));
137}
138/*---------------------------------------------------------------------------*/
clock_time_t clock_time(void)
Get the current clock time.
Definition clock.c:118
unsigned short random_rand(void)
Generates a new random number using the cc2538 RNG.
Definition random.c:58
void linkaddr_copy(linkaddr_t *dest, const linkaddr_t *src)
Copy a link-layer address.
Definition linkaddr.c:63
bool linkaddr_cmp(const linkaddr_t *addr1, const linkaddr_t *addr2)
Compare two link-layer addresses.
Definition linkaddr.c:69
void mac_sequence_set_dsn(void)
Sets and increments the destination sequence number.
int mac_sequence_is_duplicate(void)
Tell whether the packetbuf is a duplicate packet.
void mac_sequence_register_seqno(void)
Register the sequence number of the packetbuf.
void mac_sequence_init(void)
brief Initializes the destination sequence number to a random value.
Header file for MAC sequence numbers management.
Header file for the Packet buffer (packetbuf) management.