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| #include "net/mac/csma/csma.h" #include "net/mac/csma/csma-security.h" #include "net/packetbuf.h" #include "net/queuebuf.h" #include "dev/watchdog.h" #include "sys/ctimer.h" #include "sys/clock.h" #include "lib/random.h" #include "net/netstack.h" #include "lib/list.h" #include "lib/memb.h" #include "lib/assert.h"
#include "sys/log.h" #define LOG_MODULE "CSMA" #define LOG_LEVEL LOG_LEVEL_MAC
#ifdef CSMA_CONF_MIN_BE #define CSMA_MIN_BE CSMA_CONF_MIN_BE #else #define CSMA_MIN_BE 3 #endif
#ifdef CSMA_CONF_MAX_BE #define CSMA_MAX_BE CSMA_CONF_MAX_BE #else #define CSMA_MAX_BE 5 #endif
#ifdef CSMA_CONF_MAX_BACKOFF #define CSMA_MAX_BACKOFF CSMA_CONF_MAX_BACKOFF #else #define CSMA_MAX_BACKOFF 5 #endif
#ifdef CSMA_CONF_MAX_FRAME_RETRIES #define CSMA_MAX_FRAME_RETRIES CSMA_CONF_MAX_FRAME_RETRIES #else #define CSMA_MAX_FRAME_RETRIES 7 #endif
struct qbuf_metadata { mac_callback_t sent; void *cptr; uint8_t max_transmissions; };
struct neighbor_queue { struct neighbor_queue *next; linkaddr_t addr; struct ctimer transmit_timer; uint8_t transmissions; uint8_t collisions; LIST_STRUCT(packet_queue); };
#ifdef CSMA_CONF_MAX_NEIGHBOR_QUEUES #define CSMA_MAX_NEIGHBOR_QUEUES CSMA_CONF_MAX_NEIGHBOR_QUEUES #else #define CSMA_MAX_NEIGHBOR_QUEUES 2 #endif
#ifdef CSMA_CONF_MAX_PACKET_PER_NEIGHBOR #define CSMA_MAX_PACKET_PER_NEIGHBOR CSMA_CONF_MAX_PACKET_PER_NEIGHBOR #else #define CSMA_MAX_PACKET_PER_NEIGHBOR MAX_QUEUED_PACKETS #endif
#define MAX_QUEUED_PACKETS QUEUEBUF_NUM
struct packet_queue { struct packet_queue *next; struct queuebuf *buf; void *ptr; };
MEMB(neighbor_memb, struct neighbor_queue, CSMA_MAX_NEIGHBOR_QUEUES); MEMB(packet_memb, struct packet_queue, MAX_QUEUED_PACKETS); MEMB(metadata_memb, struct qbuf_metadata, MAX_QUEUED_PACKETS); LIST(neighbor_list);
static void packet_sent(struct neighbor_queue *n, struct packet_queue *q, int status, int num_transmissions); static void transmit_from_queue(void *ptr);
static struct neighbor_queue * neighbor_queue_from_addr(const linkaddr_t *addr) { struct neighbor_queue *n = list_head(neighbor_list); while(n != NULL) { if(linkaddr_cmp(&n->addr, addr)) { return n; } n = list_item_next(n); } return NULL; }
static clock_time_t backoff_period(void) { #if CONTIKI_TARGET_COOJA return MAX(20 * CLOCK_SECOND / 3125, 1); #else return MAX(CLOCK_SECOND / 3125, 1); #endif }
static int send_one_packet(struct neighbor_queue *n, struct packet_queue *q) { int ret; int last_sent_ok = 0;
packetbuf_set_addr(PACKETBUF_ADDR_SENDER, &linkaddr_node_addr); packetbuf_set_attr(PACKETBUF_ATTR_MAC_ACK, 1);
#if LLSEC802154_ENABLED #if LLSEC802154_USES_EXPLICIT_KEYS packetbuf_set_attr(PACKETBUF_ATTR_KEY_ID_MODE, CSMA_LLSEC_KEY_ID_MODE); #endif #endif
if(csma_security_create_frame() < 0) { LOG_ERR("failed to create packet, seqno: %d\n", packetbuf_attr(PACKETBUF_ATTR_MAC_SEQNO)); ret = MAC_TX_ERR_FATAL; } else { int is_broadcast; uint8_t dsn; dsn = ((uint8_t *)packetbuf_hdrptr())[2] & 0xff;
NETSTACK_RADIO.prepare(packetbuf_hdrptr(), packetbuf_totlen());
is_broadcast = packetbuf_holds_broadcast();
if(NETSTACK_RADIO.receiving_packet() || (!is_broadcast && NETSTACK_RADIO.pending_packet())) { ret = MAC_TX_COLLISION; } else { switch(NETSTACK_RADIO.transmit(packetbuf_totlen())) { case RADIO_TX_OK: if(is_broadcast) { ret = MAC_TX_OK; } else {
RTIMER_BUSYWAIT_UNTIL(NETSTACK_RADIO.pending_packet(), CSMA_ACK_WAIT_TIME); ret = MAC_TX_NOACK; if(NETSTACK_RADIO.receiving_packet() ||NETSTACK_RADIO.pending_packet() ||NETSTACK_RADIO.channel_clear() == 0) { int len; uint8_t ackbuf[CSMA_ACK_LEN]; RTIMER_BUSYWAIT_UNTIL(NETSTACK_RADIO.pending_packet(), CSMA_AFTER_ACK_DETECTED_WAIT_TIME); if(NETSTACK_RADIO.pending_packet()) { len = NETSTACK_RADIO.read(ackbuf, CSMA_ACK_LEN); if(len == CSMA_ACK_LEN && ackbuf[2] == dsn) { ret = MAC_TX_OK; } else { ret = MAC_TX_COLLISION; } } } } break; case RADIO_TX_COLLISION: ret = MAC_TX_COLLISION; break; default: ret = MAC_TX_ERR; break; } } } if(ret == MAC_TX_OK) { last_sent_ok = 1; } packet_sent(n, q, ret, 1); return last_sent_ok; }
static void transmit_from_queue(void *ptr) { struct neighbor_queue *n = ptr; if(n) { struct packet_queue *q = list_head(n->packet_queue); if(q != NULL) { LOG_INFO("preparing packet for "); LOG_INFO_LLADDR(&n->addr); LOG_INFO_(", seqno %u, tx %u, queue %d\n", queuebuf_attr(q->buf, PACKETBUF_ATTR_MAC_SEQNO), n->transmissions, list_length(n->packet_queue)); queuebuf_to_packetbuf(q->buf); send_one_packet(n, q); } } }
static void schedule_transmission(struct neighbor_queue *n) { clock_time_t delay; int backoff_exponent; backoff_exponent = MIN(n->collisions + CSMA_MIN_BE, CSMA_MAX_BE); delay = ((1 << backoff_exponent) - 1) * backoff_period(); if(delay > 0) { delay = random_rand() % delay; } LOG_DBG("scheduling transmission in %u ticks, NB=%u, BE=%u\n", (unsigned)delay, n->collisions, backoff_exponent); ctimer_set(&n->transmit_timer, delay, transmit_from_queue, n); }
static void free_packet(struct neighbor_queue *n, struct packet_queue *p, int status) { if(p != NULL) { list_remove(n->packet_queue, p); queuebuf_free(p->buf); memb_free(&metadata_memb, p->ptr); memb_free(&packet_memb, p); LOG_DBG("free_queued_packet, queue length %d, free packets %d\n", list_length(n->packet_queue), memb_numfree(&packet_memb)); if(list_head(n->packet_queue) != NULL) { n->transmissions = 0; n->collisions = 0; schedule_transmission(n); } else { ctimer_stop(&n->transmit_timer); list_remove(neighbor_list, n); memb_free(&neighbor_memb, n); } } }
static void tx_done(int status, struct packet_queue *q, struct neighbor_queue *n) { mac_callback_t sent; struct qbuf_metadata *metadata; void *cptr; uint8_t ntx; metadata = (struct qbuf_metadata *)q->ptr; sent = metadata->sent; cptr = metadata->cptr; ntx = n->transmissions; LOG_INFO("packet sent to "); LOG_INFO_LLADDR(&n->addr); LOG_INFO_(", seqno %u, status %u, tx %u, coll %u\n", packetbuf_attr(PACKETBUF_ATTR_MAC_SEQNO), status, n->transmissions, n->collisions); free_packet(n, q, status); mac_call_sent_callback(sent, cptr, status, ntx); }
static void rexmit(struct packet_queue *q, struct neighbor_queue *n) { schedule_transmission(n); queuebuf_update_attr_from_packetbuf(q->buf); }
static void collision(struct packet_queue *q, struct neighbor_queue *n, int num_transmissions) { struct qbuf_metadata *metadata;
metadata = (struct qbuf_metadata *)q->ptr;
n->collisions += num_transmissions;
if(n->collisions > CSMA_MAX_BACKOFF) { n->collisions = 0; n->transmissions++; }
if(n->transmissions >= metadata->max_transmissions) { tx_done(MAC_TX_COLLISION, q, n); } else { rexmit(q, n); } }
static void noack(struct packet_queue *q, struct neighbor_queue *n, int num_transmissions) { struct qbuf_metadata *metadata; metadata = (struct qbuf_metadata *)q->ptr; n->collisions = 0; n->transmissions += num_transmissions; if(n->transmissions >= metadata->max_transmissions) { tx_done(MAC_TX_NOACK, q, n); } else { rexmit(q, n); } }
static void tx_ok(struct packet_queue *q, struct neighbor_queue *n, int num_transmissions) { n->collisions = 0; n->transmissions += num_transmissions; tx_done(MAC_TX_OK, q, n); }
static void packet_sent(struct neighbor_queue *n, struct packet_queue *q, int status, int num_transmissions) { assert(n != NULL); assert(q != NULL); if(q->ptr == NULL) { LOG_WARN("packet sent: no metadata\n"); return; } LOG_INFO("tx to "); LOG_INFO_LLADDR(&n->addr); LOG_INFO_(", seqno %u, status %u, tx %u, coll %u\n", packetbuf_attr(PACKETBUF_ATTR_MAC_SEQNO), status, n->transmissions, n->collisions); switch(status) { case MAC_TX_OK: tx_ok(q, n, num_transmissions); break; case MAC_TX_NOACK: noack(q, n, num_transmissions); break; case MAC_TX_COLLISION: collision(q, n, num_transmissions); break; case MAC_TX_DEFERRED: break; default: tx_done(status, q, n); break; } }
void csma_output_packet(mac_callback_t sent, void *ptr) { struct packet_queue *q; struct neighbor_queue *n; static uint8_t initialized = 0; static uint8_t seqno; const linkaddr_t *addr = packetbuf_addr(PACKETBUF_ADDR_RECEIVER); if(!initialized) { initialized = 1; seqno = random_rand(); } if(seqno == 0) { seqno++; } packetbuf_set_attr(PACKETBUF_ATTR_MAC_SEQNO, seqno++); packetbuf_set_attr(PACKETBUF_ATTR_FRAME_TYPE, FRAME802154_DATAFRAME); n = neighbor_queue_from_addr(addr); if(n == NULL) { n = memb_alloc(&neighbor_memb); if(n != NULL) { linkaddr_copy(&n->addr, addr); n->transmissions = 0; n->collisions = 0; LIST_STRUCT_INIT(n, packet_queue); list_add(neighbor_list, n); } }
if(n != NULL) { if(list_length(n->packet_queue) < CSMA_MAX_PACKET_PER_NEIGHBOR) { q = memb_alloc(&packet_memb); if(q != NULL) { q->ptr = memb_alloc(&metadata_memb); if(q->ptr != NULL) { q->buf = queuebuf_new_from_packetbuf(); if(q->buf != NULL) { struct qbuf_metadata *metadata = (struct qbuf_metadata *)q->ptr; metadata->max_transmissions = packetbuf_attr(PACKETBUF_ATTR_MAX_MAC_TRANSMISSIONS); if(metadata->max_transmissions == 0) { metadata->max_transmissions = CSMA_MAX_FRAME_RETRIES + 1; } metadata->sent = sent; metadata->cptr = ptr; list_add(n->packet_queue, q);
LOG_INFO("sending to "); LOG_INFO_LLADDR(addr); LOG_INFO_(", len %u, seqno %u, queue length %d, free packets %d\n", packetbuf_datalen(), packetbuf_attr(PACKETBUF_ATTR_MAC_SEQNO), list_length(n->packet_queue), memb_numfree(&packet_memb)); if(list_head(n->packet_queue) == q) { schedule_transmission(n); } return; } memb_free(&metadata_memb, q->ptr); LOG_WARN("could not allocate queuebuf, dropping packet\n"); } memb_free(&packet_memb, q); LOG_WARN("could not allocate queuebuf, dropping packet\n"); } if(list_length(n->packet_queue) == 0) { list_remove(neighbor_list, n); memb_free(&neighbor_memb, n); } } else { LOG_WARN("Neighbor queue full\n"); } LOG_WARN("could not allocate packet, dropping packet\n"); } else { LOG_WARN("could not allocate neighbor, dropping packet\n"); } mac_call_sent_callback(sent, ptr, MAC_TX_QUEUE_FULL, 1); }
void csma_output_init(void) { memb_init(&packet_memb); memb_init(&metadata_memb); memb_init(&neighbor_memb); }
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