gnrc_lwmac_timeout_t *_lwmac_acquire_timeout(gnrc_netif_t *netif,
gnrc_lwmac_timeout_type_t type)
{
assert(netif);
if (gnrc_lwmac_timeout_is_running(netif, type)) {
return NULL;
}
for (unsigned i = 0; i < GNRC_LWMAC_TIMEOUT_COUNT; i++) {
if (netif->mac.prot.lwmac.timeouts[i].type == GNRC_LWMAC_TIMEOUT_DISABLED) {
netif->mac.prot.lwmac.timeouts[i].type = type;
return &netif->mac.prot.lwmac.timeouts[i];
}
}
return NULL;
}
static void _lwmac_update_listening(gnrc_netif_t *netif)
{
/* In case has pending packet to send, clear rtt alarm thus to goto
* transmission initialization (in SLEEPING management) right after the
* listening period */
if ((_next_tx_neighbor(netif) != NULL) ||
(netif->mac.tx.current_neighbor != NULL)) {
rtt_handler(GNRC_LWMAC_EVENT_RTT_PAUSE, netif);
}
/* Set timeout for if there's no successful rx transaction that will
* change state to SLEEPING. */
if (!gnrc_lwmac_timeout_is_running(netif, GNRC_LWMAC_TIMEOUT_WAKEUP_PERIOD)) {
gnrc_lwmac_set_timeout(netif, GNRC_LWMAC_TIMEOUT_WAKEUP_PERIOD, GNRC_LWMAC_WAKEUP_DURATION_US);
}
else if (gnrc_lwmac_timeout_is_expired(netif, GNRC_LWMAC_TIMEOUT_WAKEUP_PERIOD)) {
/* Dispatch first as there still may be broadcast packets. */
gnrc_mac_dispatch(&netif->mac.rx);
netif->mac.lwmac.state = GNRC_LWMAC_SLEEPING;
/* Enable duty cycling again */
rtt_handler(GNRC_LWMAC_EVENT_RTT_RESUME, netif);
_gnrc_lwmac_set_netdev_state(netif, NETOPT_STATE_SLEEP);
gnrc_lwmac_clear_timeout(netif, GNRC_LWMAC_TIMEOUT_WAKEUP_PERIOD);
/* if there is a packet for transmission, schedule update to start
* transmission initialization immediately. */
gnrc_mac_tx_neighbor_t *neighbour = _next_tx_neighbor(netif);
if ((neighbour != NULL) || (netif->mac.tx.current_neighbor != NULL)) {
/* This triggers packet sending procedure in sleeping immediately. */
lwmac_schedule_update(netif);
return;
}
}
if (gnrc_priority_pktqueue_length(&netif->mac.rx.queue) > 0) {
/* Do wake-up extension in each packet reception. */
gnrc_lwmac_clear_timeout(netif, GNRC_LWMAC_TIMEOUT_WAKEUP_PERIOD);
lwmac_set_state(netif, GNRC_LWMAC_RECEIVING);
}
}
static void _sleep_management(gnrc_netif_t *netif)
{
/* If a packet is scheduled, no other (possible earlier) packet can be
* sent before the first one is handled, even no broadcast
*/
if (!gnrc_lwmac_timeout_is_running(netif, GNRC_LWMAC_TIMEOUT_WAIT_DEST_WAKEUP)) {
gnrc_mac_tx_neighbor_t *neighbour;
/* Check if there is packet remaining for retransmission */
if (netif->mac.tx.current_neighbor != NULL) {
neighbour = netif->mac.tx.current_neighbor;
}
else {
/* Check if there are broadcasts to send and transmit immediately */
if (gnrc_priority_pktqueue_length(&(netif->mac.tx.neighbors[0].queue)) > 0) {
netif->mac.tx.current_neighbor = &(netif->mac.tx.neighbors[0]);
lwmac_set_state(netif, GNRC_LWMAC_TRANSMITTING);
return;
}
neighbour = _next_tx_neighbor(netif);
}
if (neighbour != NULL) {
/* if phase is unknown, send immediately. */
if (neighbour->phase > RTT_TICKS_TO_US(GNRC_LWMAC_WAKEUP_INTERVAL_US)) {
netif->mac.tx.current_neighbor = neighbour;
gnrc_lwmac_set_tx_continue(netif, false);
netif->mac.tx.tx_burst_count = 0;
lwmac_set_state(netif, GNRC_LWMAC_TRANSMITTING);
return;
}
/* Offset in microseconds when the earliest (phase) destination
* node wakes up that we have packets for. */
uint32_t time_until_tx = RTT_TICKS_TO_US(_gnrc_lwmac_ticks_until_phase(neighbour->phase));
/* If there's not enough time to prepare a WR to catch the phase
* postpone to next interval */
if (time_until_tx < GNRC_LWMAC_WR_PREPARATION_US) {
time_until_tx += GNRC_LWMAC_WAKEUP_INTERVAL_US;
}
time_until_tx -= GNRC_LWMAC_WR_PREPARATION_US;
/* add a random time before goto TX, for avoiding one node for
* always holding the medium (if the receiver's phase is recorded earlier in this
* particular node) */
uint32_t random_backoff;
random_backoff = random_uint32_range(0, GNRC_LWMAC_TIME_BETWEEN_WR_US);
time_until_tx = time_until_tx + random_backoff;
gnrc_lwmac_set_timeout(netif, GNRC_LWMAC_TIMEOUT_WAIT_DEST_WAKEUP, time_until_tx);
/* Register neighbour to be the next */
netif->mac.tx.current_neighbor = neighbour;
/* Stop dutycycling, we're preparing to send. This prevents the
* timeout arriving late, so that the destination phase would
* be missed. */
/* TODO: bad for power savings */
rtt_handler(GNRC_LWMAC_EVENT_RTT_PAUSE, netif);
}
}
else if (gnrc_lwmac_timeout_is_expired(netif, GNRC_LWMAC_TIMEOUT_WAIT_DEST_WAKEUP)) {
LOG_DEBUG("[LWMAC] Got timeout for dest wakeup, ticks: %" PRIu32 "\n", rtt_get_counter());
gnrc_lwmac_set_tx_continue(netif, false);
netif->mac.tx.tx_burst_count = 0;
lwmac_set_state(netif, GNRC_LWMAC_TRANSMITTING);
}
}
static uint8_t _send_bcast(gnrc_netif_t *netif)
{
assert(netif != NULL);
uint8_t tx_info = 0;
gnrc_pktsnip_t *pkt = netif->mac.tx.packet;
bool first = false;
if (gnrc_lwmac_timeout_is_running(netif, GNRC_LWMAC_TIMEOUT_BROADCAST_END)) {
if (gnrc_lwmac_timeout_is_expired(netif, GNRC_LWMAC_TIMEOUT_BROADCAST_END)) {
gnrc_lwmac_clear_timeout(netif, GNRC_LWMAC_TIMEOUT_NEXT_BROADCAST);
gnrc_pktbuf_release(pkt);
netif->mac.tx.packet = NULL;
tx_info |= GNRC_LWMAC_TX_SUCCESS;
return tx_info;
}
}
else {
LOG_INFO("[LWMAC-tx] Initialize broadcasting\n");
gnrc_lwmac_set_timeout(netif, GNRC_LWMAC_TIMEOUT_BROADCAST_END,
GNRC_LWMAC_BROADCAST_DURATION_US);
gnrc_pktsnip_t *pkt_payload;
/* Prepare packet with LWMAC header*/
gnrc_lwmac_frame_broadcast_t hdr;
hdr.header.type = GNRC_LWMAC_FRAMETYPE_BROADCAST;
hdr.seq_nr = netif->mac.tx.bcast_seqnr++;
pkt_payload = pkt->next;
pkt->next = gnrc_pktbuf_add(pkt->next, &hdr, sizeof(hdr), GNRC_NETTYPE_LWMAC);
if (pkt->next == NULL) {
LOG_ERROR("ERROR: [LWMAC-tx] Cannot allocate pktbuf of type FRAMETYPE_BROADCAST\n");
netif->mac.tx.packet->next = pkt_payload;
/* Drop the broadcast packet */
LOG_ERROR("ERROR: [LWMAC-tx] Memory maybe full, drop the broadcast packet\n");
gnrc_pktbuf_release(netif->mac.tx.packet);
/* clear packet point to avoid TX retry */
netif->mac.tx.packet = NULL;
tx_info |= GNRC_LWMAC_TX_FAIL;
return tx_info;
}
/* No Auto-ACK for broadcast packets */
netopt_enable_t autoack = NETOPT_DISABLE;
netif->dev->driver->set(netif->dev, NETOPT_AUTOACK, &autoack,
sizeof(autoack));
first = true;
}
if (gnrc_lwmac_timeout_is_expired(netif, GNRC_LWMAC_TIMEOUT_NEXT_BROADCAST) ||
first) {
/* if found ongoing transmission, quit this cycle for collision avoidance.
* Broadcast packet will be re-queued and try to send in the next cycle. */
if (_gnrc_lwmac_get_netdev_state(netif) == NETOPT_STATE_RX) {
/* save pointer to netif header */
gnrc_pktsnip_t *netif_snip = pkt->next->next;
/* remove LWMAC header */
pkt->next->next = NULL;
gnrc_pktbuf_release(pkt->next);
/* make append netif header after payload again */
pkt->next = netif_snip;
if (!gnrc_mac_queue_tx_packet(&netif->mac.tx, 0, netif->mac.tx.packet)) {
gnrc_pktbuf_release(netif->mac.tx.packet);
LOG_WARNING("WARNING: [LWMAC-tx] TX queue full, drop packet\n");
}
/* drop pointer so it wont be free'd */
netif->mac.tx.packet = NULL;
tx_info |= GNRC_LWMAC_TX_FAIL;
return tx_info;
}
/* Don't let the packet be released yet, we want to send it again */
gnrc_pktbuf_hold(pkt, 1);
int res = _gnrc_lwmac_transmit(netif, pkt);
if (res < 0) {
LOG_ERROR("ERROR: [LWMAC-tx] Send broadcast pkt failed.");
tx_info |= GNRC_LWMAC_TX_FAIL;
return tx_info;
}
gnrc_lwmac_set_timeout(netif, GNRC_LWMAC_TIMEOUT_NEXT_BROADCAST,
GNRC_LWMAC_TIME_BETWEEN_BROADCAST_US);
LOG_INFO("[LWMAC-tx] Broadcast sent\n");
}
return tx_info;
}
