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