254 lines
9.1 KiB
C
254 lines
9.1 KiB
C
/*
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* Copyright (c) 2007, 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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* Testing the multihop forwarding layer (multihop) in Rime
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* \author
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* Adam Dunkels <adam@sics.se>
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*
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*
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* This example shows how to use the multihop Rime module, how
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* to use the announcement mechanism, how to manage a list
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* with the list module, and how to allocate memory with the
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* memb module.
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*
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* The multihop module provides hooks for forwarding packets
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* in a multi-hop fashion, but does not implement any routing
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* protocol. A routing mechanism must be provided by the
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* application or protocol running on top of the multihop
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* module. In this case, this example program provides the
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* routing mechanism.
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*
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* The routing mechanism implemented by this example program
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* is very simple: it forwards every incoming packet to a
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* random neighbor. The program maintains a list of neighbors,
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* which it populated through the use of the announcement
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* mechanism.
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*
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* The neighbor list is populated by incoming announcements
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* from neighbors. The program maintains a list of neighbors,
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* where each entry is allocated from a MEMB() (memory block
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* pool). Each neighbor has a timeout so that they do not
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* occupy their list entry for too long.
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*
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* When a packet arrives to the node, the function forward()
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* is called by the multihop layer. This function picks a
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* random neighbor to send the packet to. The packet is
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* forwarded by every node in the network until it reaches its
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* final destination (or is discarded in transit due to a
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* transmission error or a collision).
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*
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*/
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#include "contiki.h"
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#include "net/rime/rime.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 "dev/button-sensor.h"
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#include "dev/leds.h"
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#include <stdio.h>
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#define CHANNEL 135
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struct example_neighbor {
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struct example_neighbor *next;
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linkaddr_t addr;
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struct ctimer ctimer;
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};
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#define NEIGHBOR_TIMEOUT 60 * CLOCK_SECOND
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#define MAX_NEIGHBORS 16
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LIST(neighbor_table);
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MEMB(neighbor_mem, struct example_neighbor, MAX_NEIGHBORS);
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/*---------------------------------------------------------------------------*/
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PROCESS(example_multihop_process, "multihop example");
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AUTOSTART_PROCESSES(&example_multihop_process);
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/*---------------------------------------------------------------------------*/
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/*
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* This function is called by the ctimer present in each neighbor
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* table entry. The function removes the neighbor from the table
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* because it has become too old.
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*/
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static void
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remove_neighbor(void *n)
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{
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struct example_neighbor *e = n;
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list_remove(neighbor_table, e);
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memb_free(&neighbor_mem, e);
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}
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/*---------------------------------------------------------------------------*/
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/*
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* This function is called when an incoming announcement arrives. The
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* function checks the neighbor table to see if the neighbor is
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* already present in the list. If the neighbor is not present in the
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* list, a new neighbor table entry is allocated and is added to the
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* neighbor table.
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*/
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static void
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received_announcement(struct announcement *a,
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const linkaddr_t *from,
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uint16_t id, uint16_t value)
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{
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struct example_neighbor *e;
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/* printf("Got announcement from %d.%d, id %d, value %d\n",
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from->u8[0], from->u8[1], id, value);*/
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/* We received an announcement from a neighbor so we need to update
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the neighbor list, or add a new entry to the table. */
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for(e = list_head(neighbor_table); e != NULL; e = e->next) {
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if(linkaddr_cmp(from, &e->addr)) {
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/* Our neighbor was found, so we update the timeout. */
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ctimer_set(&e->ctimer, NEIGHBOR_TIMEOUT, remove_neighbor, e);
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return;
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}
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}
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/* The neighbor was not found in the list, so we add a new entry by
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allocating memory from the neighbor_mem pool, fill in the
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necessary fields, and add it to the list. */
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e = memb_alloc(&neighbor_mem);
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if(e != NULL) {
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linkaddr_copy(&e->addr, from);
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list_add(neighbor_table, e);
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ctimer_set(&e->ctimer, NEIGHBOR_TIMEOUT, remove_neighbor, e);
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}
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}
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static struct announcement example_announcement;
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/*---------------------------------------------------------------------------*/
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/*
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* This function is called at the final recepient of the message.
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*/
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static void
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recv(struct multihop_conn *c, const linkaddr_t *sender,
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const linkaddr_t *prevhop,
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uint8_t hops)
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{
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printf("multihop message received '%s'\n", (char *)packetbuf_dataptr());
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}
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/*
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* This function is called to forward a packet. The function picks a
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* random neighbor from the neighbor list and returns its address. The
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* multihop layer sends the packet to this address. If no neighbor is
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* found, the function returns NULL to signal to the multihop layer
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* that the packet should be dropped.
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*/
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static linkaddr_t *
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forward(struct multihop_conn *c,
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const linkaddr_t *originator, const linkaddr_t *dest,
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const linkaddr_t *prevhop, uint8_t hops)
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{
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/* Find a random neighbor to send to. */
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int num, i;
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struct example_neighbor *n;
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if(list_length(neighbor_table) > 0) {
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num = random_rand() % list_length(neighbor_table);
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i = 0;
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for(n = list_head(neighbor_table); n != NULL && i != num; n = n->next) {
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++i;
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}
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if(n != NULL) {
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printf("%d.%d: Forwarding packet to %d.%d (%d in list), hops %d\n",
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linkaddr_node_addr.u8[0], linkaddr_node_addr.u8[1],
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n->addr.u8[0], n->addr.u8[1], num,
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packetbuf_attr(PACKETBUF_ATTR_HOPS));
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return &n->addr;
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}
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}
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printf("%d.%d: did not find a neighbor to foward to\n",
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linkaddr_node_addr.u8[0], linkaddr_node_addr.u8[1]);
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return NULL;
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}
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static const struct multihop_callbacks multihop_call = {recv, forward};
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static struct multihop_conn multihop;
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/*---------------------------------------------------------------------------*/
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PROCESS_THREAD(example_multihop_process, ev, data)
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{
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PROCESS_EXITHANDLER(multihop_close(&multihop);)
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PROCESS_BEGIN();
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/* Initialize the memory for the neighbor table entries. */
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memb_init(&neighbor_mem);
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/* Initialize the list used for the neighbor table. */
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list_init(neighbor_table);
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/* Open a multihop connection on Rime channel CHANNEL. */
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multihop_open(&multihop, CHANNEL, &multihop_call);
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/* Register an announcement with the same announcement ID as the
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Rime channel we use to open the multihop connection above. */
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announcement_register(&example_announcement,
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CHANNEL,
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received_announcement);
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/* Set a dummy value to start sending out announcments. */
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announcement_set_value(&example_announcement, 0);
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/* Activate the button sensor. We use the button to drive traffic -
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when the button is pressed, a packet is sent. */
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SENSORS_ACTIVATE(button_sensor);
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/* Loop forever, send a packet when the button is pressed. */
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while(1) {
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linkaddr_t to;
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/* Wait until we get a sensor event with the button sensor as data. */
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PROCESS_WAIT_EVENT_UNTIL(ev == sensors_event &&
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data == &button_sensor);
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/* Copy the "Hello" to the packet buffer. */
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packetbuf_copyfrom("Hello", 6);
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/* Set the Rime address of the final receiver of the packet to
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1.0. This is a value that happens to work nicely in a Cooja
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simulation (because the default simulation setup creates one
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node with address 1.0). */
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to.u8[0] = 1;
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to.u8[1] = 0;
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/* Send the packet. */
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multihop_send(&multihop, &to);
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}
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PROCESS_END();
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}
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/*---------------------------------------------------------------------------*/
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