nes-proj/examples/rime/example-neighbors.c

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/*
* Copyright (c) 2010, Swedish Institute of Computer Science.
* 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
* Demonstrates how to use broadcast and unicast
* \author
* Adam Dunkels <adam@sics.se>
*
* This example shows how to send broadcast and unicast, as
* well as how to use the Contiki memory block manager (MEMB)
* and the Contiki list library (LIST) to keep track of
* neighbors. The program consists of two processes, one that
* periodically sends broadcast messages and one that
* periodically sends unicast messages to random neighbors. A
* list of neighbors is maintained. The list is populated from
* the reception of broadcast messages from neighbors. The
* neighbor list keeps a simple set of quality metrics for
* each neighbor: a moving average of sequence number gaps,
* which indicates the number of broadcast packets that have
* been lost; a the last RSSI received; and the last LQI
* received.
*/
#include "contiki.h"
#include "lib/list.h"
#include "lib/memb.h"
#include "lib/random.h"
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#include "net/rime/rime.h"
#include <stdio.h>
/* This is the structure of broadcast messages. */
struct broadcast_message {
uint8_t seqno;
};
/* This is the structure of unicast ping messages. */
struct unicast_message {
uint8_t type;
};
/* These are the types of unicast messages that we can send. */
enum {
UNICAST_TYPE_PING,
UNICAST_TYPE_PONG
};
/* This structure holds information about neighbors. */
struct neighbor {
/* The ->next pointer is needed since we are placing these on a
Contiki list. */
struct neighbor *next;
/* The ->addr field holds the Rime address of the neighbor. */
linkaddr_t addr;
/* The ->last_rssi and ->last_lqi fields hold the Received Signal
Strength Indicator (RSSI) and CC2420 Link Quality Indicator (LQI)
values that are received for the incoming broadcast packets. */
uint16_t last_rssi, last_lqi;
/* Each broadcast packet contains a sequence number (seqno). The
->last_seqno field holds the last sequenuce number we saw from
this neighbor. */
uint8_t last_seqno;
/* The ->avg_gap contains the average seqno gap that we have seen
from this neighbor. */
uint32_t avg_seqno_gap;
};
/* This #define defines the maximum amount of neighbors we can remember. */
#define MAX_NEIGHBORS 16
/* This MEMB() definition defines a memory pool from which we allocate
neighbor entries. */
MEMB(neighbors_memb, struct neighbor, MAX_NEIGHBORS);
/* The neighbors_list is a Contiki list that holds the neighbors we
have seen thus far. */
LIST(neighbors_list);
/* These hold the broadcast and unicast structures, respectively. */
static struct broadcast_conn broadcast;
static struct unicast_conn unicast;
/* These two defines are used for computing the moving average for the
broadcast sequence number gaps. */
#define SEQNO_EWMA_UNITY 0x100
#define SEQNO_EWMA_ALPHA 0x040
/*---------------------------------------------------------------------------*/
/* We first declare our two processes. */
PROCESS(broadcast_process, "Broadcast process");
PROCESS(unicast_process, "Unicast process");
/* The AUTOSTART_PROCESSES() definition specifices what processes to
start when this module is loaded. We put both our processes
there. */
AUTOSTART_PROCESSES(&broadcast_process, &unicast_process);
/*---------------------------------------------------------------------------*/
/* This function is called whenever a broadcast message is received. */
static void
broadcast_recv(struct broadcast_conn *c, const linkaddr_t *from)
{
struct neighbor *n;
struct broadcast_message *m;
uint8_t seqno_gap;
/* The packetbuf_dataptr() returns a pointer to the first data byte
in the received packet. */
m = packetbuf_dataptr();
/* Check if we already know this neighbor. */
for(n = list_head(neighbors_list); n != NULL; n = list_item_next(n)) {
/* We break out of the loop if the address of the neighbor matches
the address of the neighbor from which we received this
broadcast message. */
if(linkaddr_cmp(&n->addr, from)) {
break;
}
}
/* If n is NULL, this neighbor was not found in our list, and we
allocate a new struct neighbor from the neighbors_memb memory
pool. */
if(n == NULL) {
n = memb_alloc(&neighbors_memb);
/* If we could not allocate a new neighbor entry, we give up. We
could have reused an old neighbor entry, but we do not do this
for now. */
if(n == NULL) {
return;
}
/* Initialize the fields. */
linkaddr_copy(&n->addr, from);
n->last_seqno = m->seqno - 1;
n->avg_seqno_gap = SEQNO_EWMA_UNITY;
/* Place the neighbor on the neighbor list. */
list_add(neighbors_list, n);
}
/* We can now fill in the fields in our neighbor entry. */
n->last_rssi = packetbuf_attr(PACKETBUF_ATTR_RSSI);
n->last_lqi = packetbuf_attr(PACKETBUF_ATTR_LINK_QUALITY);
/* Compute the average sequence number gap we have seen from this neighbor. */
seqno_gap = m->seqno - n->last_seqno;
n->avg_seqno_gap = (((uint32_t)seqno_gap * SEQNO_EWMA_UNITY) *
SEQNO_EWMA_ALPHA) / SEQNO_EWMA_UNITY +
((uint32_t)n->avg_seqno_gap * (SEQNO_EWMA_UNITY -
SEQNO_EWMA_ALPHA)) /
SEQNO_EWMA_UNITY;
/* Remember last seqno we heard. */
n->last_seqno = m->seqno;
/* Print out a message. */
printf("broadcast message received from %d.%d with seqno %d, RSSI %u, LQI %u, avg seqno gap %d.%02d\n",
from->u8[0], from->u8[1],
m->seqno,
packetbuf_attr(PACKETBUF_ATTR_RSSI),
packetbuf_attr(PACKETBUF_ATTR_LINK_QUALITY),
(int)(n->avg_seqno_gap / SEQNO_EWMA_UNITY),
(int)(((100UL * n->avg_seqno_gap) / SEQNO_EWMA_UNITY) % 100));
}
/* This is where we define what function to be called when a broadcast
is received. We pass a pointer to this structure in the
broadcast_open() call below. */
static const struct broadcast_callbacks broadcast_call = {broadcast_recv};
/*---------------------------------------------------------------------------*/
/* This function is called for every incoming unicast packet. */
static void
recv_uc(struct unicast_conn *c, const linkaddr_t *from)
{
struct unicast_message *msg;
/* Grab the pointer to the incoming data. */
msg = packetbuf_dataptr();
/* We have two message types, UNICAST_TYPE_PING and
UNICAST_TYPE_PONG. If we receive a UNICAST_TYPE_PING message, we
print out a message and return a UNICAST_TYPE_PONG. */
if(msg->type == UNICAST_TYPE_PING) {
printf("unicast ping received from %d.%d\n",
from->u8[0], from->u8[1]);
msg->type = UNICAST_TYPE_PONG;
packetbuf_copyfrom(msg, sizeof(struct unicast_message));
/* Send it back to where it came from. */
unicast_send(c, from);
}
}
static const struct unicast_callbacks unicast_callbacks = {recv_uc};
/*---------------------------------------------------------------------------*/
PROCESS_THREAD(broadcast_process, ev, data)
{
static struct etimer et;
static uint8_t seqno;
struct broadcast_message msg;
PROCESS_EXITHANDLER(broadcast_close(&broadcast);)
PROCESS_BEGIN();
broadcast_open(&broadcast, 129, &broadcast_call);
while(1) {
/* Send a broadcast every 16 - 32 seconds */
etimer_set(&et, CLOCK_SECOND * 16 + random_rand() % (CLOCK_SECOND * 16));
PROCESS_WAIT_EVENT_UNTIL(etimer_expired(&et));
msg.seqno = seqno;
packetbuf_copyfrom(&msg, sizeof(struct broadcast_message));
broadcast_send(&broadcast);
seqno++;
}
PROCESS_END();
}
/*---------------------------------------------------------------------------*/
PROCESS_THREAD(unicast_process, ev, data)
{
PROCESS_EXITHANDLER(unicast_close(&unicast);)
PROCESS_BEGIN();
unicast_open(&unicast, 146, &unicast_callbacks);
while(1) {
static struct etimer et;
struct unicast_message msg;
struct neighbor *n;
int randneighbor, i;
etimer_set(&et, CLOCK_SECOND * 8 + random_rand() % (CLOCK_SECOND * 8));
PROCESS_WAIT_EVENT_UNTIL(etimer_expired(&et));
/* Pick a random neighbor from our list and send a unicast message to it. */
if(list_length(neighbors_list) > 0) {
randneighbor = random_rand() % list_length(neighbors_list);
n = list_head(neighbors_list);
for(i = 0; i < randneighbor; i++) {
n = list_item_next(n);
}
printf("sending unicast to %d.%d\n", n->addr.u8[0], n->addr.u8[1]);
msg.type = UNICAST_TYPE_PING;
packetbuf_copyfrom(&msg, sizeof(msg));
unicast_send(&unicast, &n->addr);
}
}
PROCESS_END();
}
/*---------------------------------------------------------------------------*/