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platform independent simple slotted tdma mac protocol

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observe: uses event timers, not real-time timers!
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fros4943 2007-08-31 13:42:22 +00:00
parent 34af8fbc1a
commit 858e2682e6
2 changed files with 292 additions and 0 deletions
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248
core/net/mac/tdma_mac.c Normal file
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/*
* Copyright (c) 2007, 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.
*
* $Id: tdma_mac.c,v 1.1 2007/08/31 13:42:22 fros4943 Exp $
*/
#include "contiki.h"
#include "net/mac/tdma_mac.h"
#include "net/rime/rimebuf.h"
#include "net/uip-fw.h"
#include "lib/memb.h"
#include "lib/list.h"
#include "node-id.h"
#include <string.h>
#include <stdio.h>
static const struct radio_driver *radio;
static void (* receiver_callback)(const struct mac_driver *);
static int id_counter = 0;
#define DEBUG 1
#if DEBUG
/*#include "printf2log.h"*/ /* XXX COOJA specifics */
#define PRINTF(...) printf(__VA_ARGS__)
#else
#define PRINTF(...)
#endif
/* TDMA configuration */
#define MAX_BUFFERED_PACKETS 6
#define NR_SLOTS 10
#define SLOT_LENGTH (CLOCK_SECOND) /* Slot length */
#define GUARD_PERIOD (CLOCK_SECOND / 2) /* Approx. packet transmission time */
#define MY_SLOT (node_id % NR_SLOTS)
#define PERIOD_LENGTH (SLOT_LENGTH*NR_SLOTS)
enum {
EVENT_PACKET_BUFFERED
};
struct buf_packet {
struct buf_packet *next;
struct queuebuf *queued_packet;
int id;
struct etimer etimer;
};
LIST(buf_packet_list);
MEMB(buf_packet_mem, struct buf_packet, MAX_BUFFERED_PACKETS);
PROCESS(tdma_process, "TDMA process");
/*---------------------------------------------------------------------------*/
PROCESS_THREAD(tdma_process, ev, data)
{
PROCESS_BEGIN();
while(1) {
PROCESS_YIELD();
if(ev == EVENT_PACKET_BUFFERED || ev == PROCESS_EVENT_TIMER) {
struct buf_packet *packet;
/* Locate packet */
for(packet = list_head(buf_packet_list); packet != NULL; packet = packet->next) {
if (etimer_expired(&packet->etimer)) {
int ret, rest, period_start, my_next_slot;
clock_time_t now;
/* Calculate time of our next slot */
now = clock_time();
rest = now % PERIOD_LENGTH;
period_start = now - rest;
my_next_slot = period_start + MY_SLOT*SLOT_LENGTH;
/* Transmit if inside our slot, with enough time left */
if ((now == my_next_slot) ||
(now > my_next_slot && (now - my_next_slot) < (SLOT_LENGTH-GUARD_PERIOD)))
{
PRINTF("SCHEDULE We can deliver right now (%i), slot = (%i <-> %i)\n", now, my_next_slot, my_next_slot + SLOT_LENGTH);
}
else
{
if (now > my_next_slot) {
my_next_slot += PERIOD_LENGTH;
}
int distance = my_next_slot - now;
etimer_set(&packet->etimer, distance);
PRINTF("SCHEDULE Packet #%i rescheduled at %i to %i\n", packet->id, clock_time(), my_next_slot);
continue;
}
/* Clear Rime buffer */
rimebuf_clear();
/* Restore packet from buffer */
if(packet->queued_packet != NULL) {
queuebuf_to_rimebuf(packet->queued_packet);
queuebuf_free(packet->queued_packet);
}
/* Send packet */
PRINTF("TDMA_PROC Packet #%i send starting at %i\n", packet->id, clock_time());
ret = radio->send(rimebuf_hdrptr(), rimebuf_totlen());
if (ret == UIP_FW_OK) {
/* Remove transmitted packet */
list_remove(buf_packet_list, packet);
memb_free(&buf_packet_mem, packet);
PRINTF("BUFFER Packet removed, memory freed\n");
PRINTF("TDMA_PROC Packet #%i sent at %i\n", packet->id, clock_time());
} else {
/* Reschedule packet */
etimer_set(&packet->etimer, SLOT_LENGTH);
PRINTF("TDMA_PROC Packet #%i forced rescheduled\n", packet->id);
}
}
}
}
}
PROCESS_END();
}
/*---------------------------------------------------------------------------*/
static int
send(void)
{
struct buf_packet *packet;
packet = (struct buf_packet *)memb_alloc(&buf_packet_mem);
if (packet == NULL) {
PRINTF("BUFFER No memory available, packet dropped\n");
return UIP_FW_DROPPED;
}
/* Add to buffered packets list */
list_add(buf_packet_list, packet);
PRINTF("BUFFER Packet added, memory allocated\n");
/* Store packet data */
packet->queued_packet = queuebuf_new_from_rimebuf();
if (packet->queued_packet == NULL) {
list_remove(buf_packet_list, packet);
memb_free(&buf_packet_mem, packet);
PRINTF("BUFFER No queue memory available, packet dropped\n");
return UIP_FW_DROPPED;
}
PROCESS_CONTEXT_BEGIN(&tdma_process);
etimer_set(&packet->etimer, 0);
PROCESS_CONTEXT_END(&tdma_process);
/* TODO ID only used for debugging */
packet->id = id_counter++;
/* Clear Rime buffer */
rimebuf_clear();
process_post(&tdma_process, EVENT_PACKET_BUFFERED, NULL);
return UIP_FW_OK; /* TODO Return what? */
}
/*---------------------------------------------------------------------------*/
static void
input(const struct radio_driver *d)
{
receiver_callback(&tdma_mac_driver);
}
/*---------------------------------------------------------------------------*/
static int
read(void)
{
int len;
rimebuf_clear();
len = radio->read(rimebuf_dataptr(), RIMEBUF_SIZE);
rimebuf_set_datalen(len);
return len;
}
/*---------------------------------------------------------------------------*/
static void
set_receive_function(void (* recv)(const struct mac_driver *))
{
receiver_callback = recv;
}
/*---------------------------------------------------------------------------*/
static int
on(void)
{
return radio->on();
}
/*---------------------------------------------------------------------------*/
static int
off(void)
{
return radio->off();
}
/*---------------------------------------------------------------------------*/
void
tdma_mac_init(const struct radio_driver *d)
{
memb_init(&buf_packet_mem);
list_init(buf_packet_list);
process_start(&tdma_process, NULL);
radio = d;
radio->set_receive_function(input);
radio->on();
}
/*---------------------------------------------------------------------------*/
const struct mac_driver tdma_mac_driver = {
send,
read,
set_receive_function,
on,
off,
};

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core/net/mac/tdma_mac.h Normal file
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/*
* Copyright (c) 2007, 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.
*
* $Id: tdma_mac.h,v 1.1 2007/08/31 13:42:22 fros4943 Exp $
*/
#ifndef __TDMA_MAC_H__
#define __TDMA_MAC_H__
#include "net/mac/mac.h"
#include "dev/radio.h"
extern const struct mac_driver tdma_mac_driver;
void tdma_mac_init(const struct radio_driver *r);
#endif /* __TDMA_MAC_H__ */