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RIOT/sys/net/routing/etx_beaconing.c

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/*
* ETX beaconing implementation
*
* Copyright (C) 2013 Stephan Arndt <arndtste@zedat.fu-berlin.de>
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @ingroup rpl
* @{
* @file etx_beaconing.c
* @brief ETX-beaconing implementation
*
* Implementation for ETX-based beaconing.
*
* @author Stephan Arndt <arndtste@zedat.fu-berlin.de>
* @}
*/
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include "mutex.h"
#include "hwtimer.h"
#include "vtimer.h"
#include "thread.h"
#include "transceiver.h"
#include "sixlowpan/ip.h"
#include "ieee802154_frame.h"
#include "etx_beaconing.h"
#define ENABLE_DEBUG (0)
#include "debug.h"
#if ENABLE_DEBUG
#define ETX_BEACON_STACKSIZE (KERNEL_CONF_STACKSIZE_DEFAULT + KERNEL_CONF_STACKSIZE_PRINTF_FLOAT)
#define ETX_RADIO_STACKSIZE (KERNEL_CONF_STACKSIZE_DEFAULT + KERNEL_CONF_STACKSIZE_PRINTF_FLOAT)
#define ETX_CLOCK_STACKSIZE (KERNEL_CONF_STACKSIZE_DEFAULT)
#else
#define ETX_BEACON_STACKSIZE (KERNEL_CONF_STACKSIZE_MAIN)
#define ETX_RADIO_STACKSIZE (KERNEL_CONF_STACKSIZE_MAIN)
#define ETX_CLOCK_STACKSIZE (KERNEL_CONF_STACKSIZE_DEFAULT)
#endif
/* prototytpes */
static uint8_t etx_count_packet_tx(etx_neighbor_t *candidate);
static void etx_set_packets_received(void);
static bool etx_equal_id(ipv6_addr_t *id1, ipv6_addr_t *id2);
static void *etx_beacon(void *);
static void *etx_clock(void *);
static void *etx_radio(void *);
/* Buffer */
static char etx_beacon_buf[ETX_BEACON_STACKSIZE];
static char etx_radio_buf[ETX_RADIO_STACKSIZE];
static char etx_clock_buf[ETX_CLOCK_STACKSIZE];
static uint8_t etx_send_buf[ETX_BUF_SIZE];
static uint8_t etx_rec_buf[ETX_BUF_SIZE];
/* PIDs */
static kernel_pid_t etx_beacon_pid = KERNEL_PID_UNDEF;
static kernel_pid_t etx_radio_pid = KERNEL_PID_UNDEF;
static kernel_pid_t etx_clock_pid = KERNEL_PID_UNDEF;
/* Message queue for radio */
static msg_t msg_que[ETX_RCV_QUEUE_SIZE];
/*
* The counter for the current 'round'. An ETX beacon is sent every ETX_INTERVAL
* u-seconds and a node computes the ETX value by comparing the the received
* probes vs the expected probes from a neighbor every ETX_ROUND intervals.
*/
static uint8_t cur_round;
/*
* If we have not yet reached WINDOW intervals, won't calculate the ETX just yet
*/
static char reached_window;
/*
* This could (and should) be done differently, once the RPL implementation
* deals with candidate neighbors in another way than just defining that every
* possible neighbor we hear from is a parent.
* Right now, we need to keep track of the ETX values of other nodes without
* needing them to be in our parent array, so we have another array here in
* which we put all necessary info for up to ETX_MAX_CANDIDATE_NEIHGBORS
* candidates.
*/
/* Candidate array */
static etx_neighbor_t candidates[ETX_MAX_CANDIDATE_NEIGHBORS];
/*
* Each time we send a beacon packet we need to reset some values for the
* current 'round' (a round being the time between each sent beacon packet).
*
* In this time, no packet may be handled, otherwise it could assume values
* from the last round to count for this round.
*/
static mutex_t etx_mutex = MUTEX_INIT;
static ipv6_addr_t *own_address;
static etx_probe_t *etx_get_send_buf(void)
{
return ((etx_probe_t *) &(etx_send_buf[0]));
}
static etx_probe_t *etx_get_rec_buf(void)
{
return ((etx_probe_t *) &(etx_rec_buf[0]));
}
void etx_show_candidates(void)
{
etx_neighbor_t *candidate;
etx_neighbor_t *end;
for (candidate = &candidates[0], end = candidates
+ ETX_MAX_CANDIDATE_NEIGHBORS; candidate < end;
candidate++) {
if (candidate->used == 0) {
break;
}
printf("Candidates Addr:%d\n"
"\t cur_etx:%f\n"
"\t packets_rx:%d\n"
"\t packets_tx:%d\n"
"\t used:%d\n", candidate->addr.uint8[ETX_IPV6_LAST_BYTE],
candidate->cur_etx, candidate->packets_rx,
etx_count_packet_tx(candidate),
candidate->used);
}
}
void etx_init_beaconing(ipv6_addr_t *address)
{
own_address = address;
//set code
DEBUGF("ETX BEACON INIT");
etx_send_buf[0] = ETX_PKT_OPTVAL;
etx_beacon_pid = thread_create(etx_beacon_buf, ETX_BEACON_STACKSIZE,
PRIORITY_MAIN - 1, CREATE_STACKTEST,
etx_beacon, NULL, "etx_beacon");
etx_radio_pid = thread_create(etx_radio_buf, ETX_RADIO_STACKSIZE,
PRIORITY_MAIN - 1, CREATE_STACKTEST,
etx_radio, NULL, "etx_radio");
etx_clock_pid = thread_create(etx_clock_buf, ETX_CLOCK_STACKSIZE,
PRIORITY_MAIN - 1, CREATE_STACKTEST,
etx_clock, NULL, "etx_clock");
//register at transceiver
transceiver_register(TRANSCEIVER_CC1100, etx_radio_pid);
DEBUG("...[DONE]\n");
}
static void *etx_beacon(void *arg)
{
(void) arg;
/*
* Sends a message every ETX_INTERVAL +/- a jitter-value (default is 10%) .
* A correcting variable is needed to stay at a base interval of
* ETX_INTERVAL between the wakeups. It takes the old jittervalue in account
* and modifies the time to wait accordingly.
*/
etx_probe_t *packet = etx_get_send_buf();
while (true) {
thread_sleep();
mutex_lock(&etx_mutex);
//Build etx packet
uint8_t p_length = 0;
for (uint8_t i = 0; i < ETX_BEST_CANDIDATES; i++) {
if (candidates[i].used != 0) {
packet->data[i * ETX_TUPLE_SIZE] =
candidates[i].addr.uint8[ETX_IPV6_LAST_BYTE];
packet->data[i * ETX_TUPLE_SIZE + ETX_PKT_REC_OFFSET] =
etx_count_packet_tx(&candidates[i]);
p_length = p_length + ETX_PKT_HDR_LEN;
}
}
packet->length = p_length;
/* will be send broadcast, so if_id and destination address will be
* ignored (see documentation)
*/
sixlowpan_mac_send_ieee802154_frame(0, NULL, 8, &etx_send_buf[0],
ETX_DATA_MAXLEN + ETX_PKT_HDR_LEN, 1);
DEBUG("sent beacon!\n");
etx_set_packets_received();
cur_round++;
if (cur_round == ETX_WINDOW) {
if (reached_window != 1) {
//first round is through
reached_window = 1;
}
cur_round = 0;
}
mutex_unlock(&etx_mutex);
}
return NULL;
}
etx_neighbor_t *etx_find_candidate(ipv6_addr_t *address)
{
/*
* find the candidate with address address and returns it, or returns NULL
* if no candidate having this address was found.
*/
for (uint8_t i = 0; i < ETX_MAX_CANDIDATE_NEIGHBORS; i++) {
if (candidates[i].used
&& (etx_equal_id(&candidates[i].addr, address))) {
return &candidates[i];
}
}
return NULL ;
}
static void *etx_clock(void *arg)
{
(void) arg;
/*
* Manages the etx_beacon thread to wake up every full second +- jitter
*/
/*
* The jittercorrection and jitter variables keep usecond values divided
* through 1000 to fit into uint8 variables.
*
* That is why they are multiplied by 1000 when used for hwtimer_wait.
*/
uint8_t jittercorrection = ETX_DEF_JIT_CORRECT;
uint8_t jitter = (uint8_t)(rand() % ETX_JITTER_MOD);
while (true) {
thread_wakeup(etx_beacon_pid);
/*
* Vtimer is buggy, but I seem to have no hwtimers left, so using this
* for now.
*/
vtimer_usleep(
((ETX_INTERVAL - ETX_MAX_JITTER)*MS) + jittercorrection * MS + jitter * MS - ETX_CLOCK_ADJUST);
//hwtimer_wait(
// HWTIMER_TICKS(((ETX_INTERVAL - ETX_MAX_JITTER)*MS) + jittercorrection*MS + jitter*MS - ETX_CLOCK_ADJUST));
jittercorrection = (ETX_MAX_JITTER) - jitter;
jitter = (uint8_t)(rand() % ETX_JITTER_MOD);
}
return NULL;
}
double etx_get_metric(ipv6_addr_t *address)
{
etx_neighbor_t *candidate = etx_find_candidate(address);
if (candidate != NULL) {
if (etx_count_packet_tx(candidate) > 0) {
//this means the current etx_value is not outdated
return candidate->cur_etx;
}
else {
//The last time I received a packet is too long ago to give a
//good estimate of the etx value
return 0;
}
}
return 0;
}
etx_neighbor_t *etx_add_candidate(ipv6_addr_t *address)
{
DEBUG("add candidate\n");
/*
* Pre-Condition: etx_add_candidate should only be called when the
* candidate is not yet in the list.
* Otherwise the candidate will be added a second time,
* leading to unknown behavior.
*
* Check if there is still enough space to add this candidate
*
* a)
* Space is available:
* Add candidate
*
* b)
* Space is not available:
* ignore new candidate
* This shouldn't really happen though, since we have enough
* place in the array.
*
* Returns the pointer to the candidate if it was added, or a NULL-pointer
* otherwise.
*/
etx_neighbor_t *candidate;
etx_neighbor_t *end;
for (candidate = &candidates[0], end = candidates
+ ETX_MAX_CANDIDATE_NEIGHBORS; candidate < end;
candidate++) {
if (candidate->used) {
//skip
continue;
}
else {
//We still have a free place add the new candidate
memset(candidate, 0, sizeof(*candidate));
candidate->addr = *address;
candidate->cur_etx = 0;
candidate->packets_rx = 0;
candidate->used = 1;
return candidate;
}
}
return NULL ;
}
void etx_handle_beacon(ipv6_addr_t *candidate_address)
{
/*
* Handle the ETX probe that has been received and update all infos.
* If the candidate address is unknown, try to add it to my struct.
*/
DEBUG(
"ETX beacon package received with following values:\n"
"\tPackage Option:%x\n"
"\t Data Length:%u\n"
"\tSource Address:%d\n\n", etx_rec_buf[ETX_PKT_OPT], etx_rec_buf[ETX_PKT_LEN],
candidate_address->uint8[ETX_IPV6_LAST_BYTE]);
etx_neighbor_t *candidate = etx_find_candidate(candidate_address);
if (candidate == NULL) {
//Candidate was not found in my list, I should add it
candidate = etx_add_candidate(candidate_address);
if (candidate == NULL) {
DEBUGF("[ERROR] Candidate could not get added\n");
DEBUG("Increase the constant ETX_MAX_CANDIDATE_NEIHGBORS\n");
return;
}
}
//I have received 1 packet from this candidate in this round
//This value will be reset by etx_update to 0
candidate->tx_cur_round = 1;
// If i find my address in this probe, update the packet_rx value for
// this candidate.
etx_probe_t *rec_pkt = etx_get_rec_buf();
for (uint8_t i = 0; i < rec_pkt->length / ETX_TUPLE_SIZE; i++) {
DEBUG("\tIPv6 short Addr:%u\n"
"\tPackets f. Addr:%u\n\n", rec_pkt->data[i * ETX_TUPLE_SIZE],
rec_pkt->data[i * ETX_TUPLE_SIZE + ETX_PKT_REC_OFFSET]);
if (rec_pkt->data[i * ETX_TUPLE_SIZE]
== own_address->uint8[ETX_IPV6_LAST_BYTE]) {
candidate->packets_rx = rec_pkt->data[i * ETX_TUPLE_SIZE
+ ETX_PKT_REC_OFFSET];
}
}
//Last, update the ETX value for this candidate
etx_update(candidate);
}
static void *etx_radio(void *arg)
{
(void) arg;
msg_t m;
radio_packet_t *p;
ieee802154_frame_t frame;
msg_init_queue(msg_que, ETX_RCV_QUEUE_SIZE);
ipv6_addr_t ll_address;
ipv6_addr_t candidate_addr;
ipv6_addr_set_link_local_prefix(&ll_address);
ipv6_net_if_get_best_src_addr(&candidate_addr, &ll_address);
while (1) {
msg_receive(&m);
if (m.type == PKT_PENDING) {
p = (radio_packet_t *) m.content.ptr;
ieee802154_frame_read(p->data, &frame, p->length);
if (frame.payload[0] == ETX_PKT_OPTVAL) {
//copy to receive buffer
memcpy(etx_rec_buf, &frame.payload[0], frame.payload_len);
//create IPv6 address from radio packet
//we can do the cast here since rpl nodes can only have addr
//up to 8 bits
candidate_addr.uint8[ETX_IPV6_LAST_BYTE] = (uint8_t) p->src;
//handle the beacon
mutex_lock(&etx_mutex);
etx_handle_beacon(&candidate_addr);
mutex_unlock(&etx_mutex);
}
p->processing--;
}
else if (m.type == ENOBUFFER) {
DEBUGF("Transceiver buffer full\n");
}
else {
//packet is not for me, whatever
}
}
return NULL;
}
void etx_update(etx_neighbor_t *candidate)
{
DEBUG("update!\n");
/*
* Update the current ETX value of a candidate
*/
double d_f;
double d_r;
if (reached_window != 1 || candidate == NULL) {
//We will wait at least ETX_WINDOW beacons until we decide to
//calculate an ETX value, so that we have a good estimate
return;
}
/*
* Calculate d_f (the forward PDR) from ME to this candidate.
*/
d_f = candidate->packets_rx / (double) ETX_WINDOW;
/*
* Calculate d_r (the backwards PDR) from this candidate to ME
*/
d_r = etx_count_packet_tx(candidate) / (double) ETX_WINDOW;
/*
* Calculate the current ETX value for my link to this candidate.
*/
if (d_f * d_r != 0) {
candidate->cur_etx = 1 / (d_f * d_r);
}
else {
candidate->cur_etx = 0;
}
DEBUG(
"Estimated ETX Metric is %f for candidate w/ addr %d\n"
"Estimated PDR_forward is %f\n"
"Estimated PDR_backwrd is %f\n"
"\n"
"Received Packets: %d\n"
"Sent Packets : %d\n\n",
candidate->cur_etx, candidate->addr.uint8[ETX_IPV6_LAST_BYTE],
d_f, d_r, candidate->packets_rx, etx_count_packet_tx(candidate));
}
static uint8_t etx_count_packet_tx(etx_neighbor_t *candidate)
{
/*
* Counts the number of packets that were received for this candidate
* in the last ETX_WINDOW intervals.
*/
DEBUG("counting packets");
uint8_t pkt_count = 0;
DEBUG("[");
for (uint8_t i = 0; i < ETX_WINDOW; i++) {
if (i != cur_round) {
pkt_count = pkt_count + candidate->packets_tx[i];
DEBUG("%d", candidate->packets_tx[i]);
if (i < ETX_WINDOW - 1) {
DEBUG(",");
}
}
else {
//Check if I received something for the current round
if (candidate->tx_cur_round == 0) {
//Didn't receive a packet, zero the field and don't add
candidate->packets_tx[i] = 0;
DEBUG("%d!", candidate->packets_tx[i]);
if (i < ETX_WINDOW - 1) {
DEBUG(",");
}
}
else {
//Add 1 and set field
pkt_count = pkt_count + 1;
candidate->packets_tx[i] = 1;
DEBUG("%d!", candidate->packets_tx[i]);
if (i < ETX_WINDOW - 1) {
DEBUG(",");
}
}
}
}
DEBUG("]\n");
return pkt_count;
}
static void etx_set_packets_received(void)
{
/*
* Set for all candidates if they received a packet this round or not
*/
for (uint8_t i = 0; i < ETX_MAX_CANDIDATE_NEIGHBORS; i++) {
if (candidates[i].used) {
if (candidates[i].tx_cur_round != 0) {
candidates[i].packets_tx[cur_round] = 1;
candidates[i].tx_cur_round = 0;
}
}
}
}
bool etx_equal_id(ipv6_addr_t *id1, ipv6_addr_t *id2)
{
for (uint8_t i = 0; i < 4; i++) {
if (id1->uint32[i] != id2->uint32[i]) {
return false;
}
}
return true;
}
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