/* * Copyright (c) 2015, SICS Swedish ICT. * 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. * */ /** * \file * TSCH slot operation implementation, running from interrupt. * \author * Simon Duquennoy * Beshr Al Nahas * */ #include "contiki.h" #include "dev/radio.h" #include "net/netstack.h" #include "net/packetbuf.h" #include "net/queuebuf.h" #include "net/mac/framer-802154.h" #include "net/mac/tsch/tsch.h" #include "net/mac/tsch/tsch-slot-operation.h" #include "net/mac/tsch/tsch-queue.h" #include "net/mac/tsch/tsch-private.h" #include "net/mac/tsch/tsch-log.h" #include "net/mac/tsch/tsch-packet.h" #include "net/mac/tsch/tsch-security.h" #include "net/mac/tsch/tsch-adaptive-timesync.h" #if TSCH_LOG_LEVEL >= 1 #define DEBUG DEBUG_PRINT #else /* TSCH_LOG_LEVEL */ #define DEBUG DEBUG_NONE #endif /* TSCH_LOG_LEVEL */ #include "net/ip/uip-debug.h" /* TSCH debug macros, i.e. to set LEDs or GPIOs on various TSCH * timeslot events */ #ifndef TSCH_DEBUG_INIT #define TSCH_DEBUG_INIT() #endif #ifndef TSCH_DEBUG_INTERRUPT #define TSCH_DEBUG_INTERRUPT() #endif #ifndef TSCH_DEBUG_RX_EVENT #define TSCH_DEBUG_RX_EVENT() #endif #ifndef TSCH_DEBUG_TX_EVENT #define TSCH_DEBUG_TX_EVENT() #endif #ifndef TSCH_DEBUG_SLOT_START #define TSCH_DEBUG_SLOT_START() #endif #ifndef TSCH_DEBUG_SLOT_END #define TSCH_DEBUG_SLOT_END() #endif /* Check if TSCH_MAX_INCOMING_PACKETS is power of two */ #if (TSCH_MAX_INCOMING_PACKETS & (TSCH_MAX_INCOMING_PACKETS - 1)) != 0 #error TSCH_MAX_INCOMING_PACKETS must be power of two #endif /* Check if TSCH_DEQUEUED_ARRAY_SIZE is power of two and greater or equal to QUEUEBUF_NUM */ #if TSCH_DEQUEUED_ARRAY_SIZE < QUEUEBUF_NUM #error TSCH_DEQUEUED_ARRAY_SIZE must be greater or equal to QUEUEBUF_NUM #endif #if (TSCH_DEQUEUED_ARRAY_SIZE & (TSCH_DEQUEUED_ARRAY_SIZE - 1)) != 0 #error TSCH_DEQUEUED_ARRAY_SIZE must be power of two #endif /* Truncate received drift correction information to maximum half * of the guard time (one fourth of TSCH_DEFAULT_TS_RX_WAIT) */ #define SYNC_IE_BOUND ((int32_t)US_TO_RTIMERTICKS(TSCH_DEFAULT_TS_RX_WAIT / 4)) /* By default: check that rtimer runs at >=32kHz and use a guard time of 10us */ #if RTIMER_SECOND < (32 * 1024) #error "TSCH: RTIMER_SECOND < (32 * 1024)" #endif #if RTIMER_SECOND >= 200000 #define RTIMER_GUARD (RTIMER_SECOND / 100000) #else #define RTIMER_GUARD 2u #endif /* A ringbuf storing outgoing packets after they were dequeued. * Will be processed layer by tsch_tx_process_pending */ struct ringbufindex dequeued_ringbuf; struct tsch_packet *dequeued_array[TSCH_DEQUEUED_ARRAY_SIZE]; /* A ringbuf storing incoming packets. * Will be processed layer by tsch_rx_process_pending */ struct ringbufindex input_ringbuf; struct input_packet input_array[TSCH_MAX_INCOMING_PACKETS]; /* Last time we received Sync-IE (ACK or data packet from a time source) */ static struct asn_t last_sync_asn; /* A global lock for manipulating data structures safely from outside of interrupt */ static volatile int tsch_locked = 0; /* As long as this is set, skip all slot operation */ static volatile int tsch_lock_requested = 0; /* Last estimated drift in RTIMER ticks * (Sky: 1 tick = 30.517578125 usec exactly) */ static int32_t drift_correction = 0; /* Is drift correction used? (Can be true even if drift_correction == 0) */ static uint8_t is_drift_correction_used; /* The neighbor last used as our time source */ struct tsch_neighbor *last_timesource_neighbor = NULL; /* Used from tsch_slot_operation and sub-protothreads */ static rtimer_clock_t volatile current_slot_start; /* Are we currently inside a slot? */ static volatile int tsch_in_slot_operation = 0; /* Info about the link, packet and neighbor of * the current (or next) slot */ struct tsch_link *current_link = NULL; /* A backup link with Rx flag, overlapping with current_link. * If the current link is Tx-only and the Tx queue * is empty while executing the link, fallback to the backup link. */ static struct tsch_link *backup_link = NULL; static struct tsch_packet *current_packet = NULL; static struct tsch_neighbor *current_neighbor = NULL; /* Protothread for association */ PT_THREAD(tsch_scan(struct pt *pt)); /* Protothread for slot operation, called from rtimer interrupt * and scheduled from tsch_schedule_slot_operation */ static PT_THREAD(tsch_slot_operation(struct rtimer *t, void *ptr)); static struct pt slot_operation_pt; /* Sub-protothreads of tsch_slot_operation */ static PT_THREAD(tsch_tx_slot(struct pt *pt, struct rtimer *t)); static PT_THREAD(tsch_rx_slot(struct pt *pt, struct rtimer *t)); /*---------------------------------------------------------------------------*/ /* TSCH locking system. TSCH is locked during slot operations */ /* Is TSCH locked? */ int tsch_is_locked(void) { return tsch_locked; } /* Lock TSCH (no slot operation) */ int tsch_get_lock(void) { if(!tsch_locked) { rtimer_clock_t busy_wait_time; int busy_wait = 0; /* Flag used for logging purposes */ /* Make sure no new slot operation will start */ tsch_lock_requested = 1; /* Wait for the end of current slot operation. */ if(tsch_in_slot_operation) { busy_wait = 1; busy_wait_time = RTIMER_NOW(); while(tsch_in_slot_operation); busy_wait_time = RTIMER_NOW() - busy_wait_time; } if(!tsch_locked) { /* Take the lock if it is free */ tsch_locked = 1; tsch_lock_requested = 0; if(busy_wait) { /* Issue a log whenever we had to busy wait until getting the lock */ TSCH_LOG_ADD(tsch_log_message, snprintf(log->message, sizeof(log->message), "!get lock delay %u", (unsigned)busy_wait_time); ); } return 1; } } TSCH_LOG_ADD(tsch_log_message, snprintf(log->message, sizeof(log->message), "!failed to lock"); ); return 0; } /* Release TSCH lock */ void tsch_release_lock(void) { tsch_locked = 0; } /*---------------------------------------------------------------------------*/ /* Channel hopping utility functions */ /* Return channel from ASN and channel offset */ uint8_t tsch_calculate_channel(struct asn_t *asn, uint8_t channel_offset) { uint16_t index_of_0 = ASN_MOD(*asn, tsch_hopping_sequence_length); uint16_t index_of_offset = (index_of_0 + channel_offset) % tsch_hopping_sequence_length.val; return tsch_hopping_sequence[index_of_offset]; } /*---------------------------------------------------------------------------*/ /* Timing utility functions */ /* Checks if the current time has passed a ref time + offset. Assumes * a single overflow and ref time prior to now. */ static uint8_t check_timer_miss(rtimer_clock_t ref_time, rtimer_clock_t offset, rtimer_clock_t now) { rtimer_clock_t target = ref_time + offset; int now_has_overflowed = now < ref_time; int target_has_overflowed = target < ref_time; if(now_has_overflowed == target_has_overflowed) { /* Both or none have overflowed, just compare now to the target */ return target <= now; } else { /* Either now or target of overflowed. * If it is now, then it has passed the target. * If it is target, then we haven't reached it yet. * */ return now_has_overflowed; } } /*---------------------------------------------------------------------------*/ /* Schedule a wakeup at a specified offset from a reference time. * Provides basic protection against missed deadlines and timer overflows * A return value of zero signals a missed deadline: no rtimer was scheduled. */ static uint8_t tsch_schedule_slot_operation(struct rtimer *tm, rtimer_clock_t ref_time, rtimer_clock_t offset, const char *str) { rtimer_clock_t now = RTIMER_NOW(); int r; /* Subtract RTIMER_GUARD before checking for deadline miss * because we can not schedule rtimer less than RTIMER_GUARD in the future */ int missed = check_timer_miss(ref_time, offset - RTIMER_GUARD, now); if(missed) { TSCH_LOG_ADD(tsch_log_message, snprintf(log->message, sizeof(log->message), "!dl-miss %s %d %d", str, (int)(now-ref_time), (int)offset); ); return 0; } ref_time += offset; r = rtimer_set(tm, ref_time, 1, (void (*)(struct rtimer *, void *))tsch_slot_operation, NULL); if(r != RTIMER_OK) { return 0; } return 1; } /*---------------------------------------------------------------------------*/ /* Schedule slot operation conditionally, and YIELD if success only. * Always attempt to schedule RTIMER_GUARD before the target to make sure to wake up * ahead of time and then busy wait to exactly hit the target. */ #define TSCH_SCHEDULE_AND_YIELD(pt, tm, ref_time, offset, str) \ do { \ if(tsch_schedule_slot_operation(tm, ref_time, offset - RTIMER_GUARD, str)) { \ PT_YIELD(pt); \ } \ BUSYWAIT_UNTIL_ABS(0, ref_time, offset); \ } while(0); /*---------------------------------------------------------------------------*/ /* Get EB, broadcast or unicast packet to be sent, and target neighbor. */ static struct tsch_packet * get_packet_and_neighbor_for_link(struct tsch_link *link, struct tsch_neighbor **target_neighbor) { struct tsch_packet *p = NULL; struct tsch_neighbor *n = NULL; /* Is this a Tx link? */ if(link->link_options & LINK_OPTION_TX) { /* is it for advertisement of EB? */ if(link->link_type == LINK_TYPE_ADVERTISING || link->link_type == LINK_TYPE_ADVERTISING_ONLY) { /* fetch EB packets */ n = n_eb; p = tsch_queue_get_packet_for_nbr(n, link); } if(link->link_type != LINK_TYPE_ADVERTISING_ONLY) { /* NORMAL link or no EB to send, pick a data packet */ if(p == NULL) { /* Get neighbor queue associated to the link and get packet from it */ n = tsch_queue_get_nbr(&link->addr); p = tsch_queue_get_packet_for_nbr(n, link); /* if it is a broadcast slot and there were no broadcast packets, pick any unicast packet */ if(p == NULL && n == n_broadcast) { p = tsch_queue_get_unicast_packet_for_any(&n, link); } } } } /* return nbr (by reference) */ if(target_neighbor != NULL) { *target_neighbor = n; } return p; } /*---------------------------------------------------------------------------*/ /* Post TX: Update neighbor state after a transmission */ static int update_neighbor_state(struct tsch_neighbor *n, struct tsch_packet *p, struct tsch_link *link, uint8_t mac_tx_status) { int in_queue = 1; int is_shared_link = link->link_options & LINK_OPTION_SHARED; int is_unicast = !n->is_broadcast; if(mac_tx_status == MAC_TX_OK) { /* Successful transmission */ tsch_queue_remove_packet_from_queue(n); in_queue = 0; /* Update CSMA state in the unicast case */ if(is_unicast) { if(is_shared_link || tsch_queue_is_empty(n)) { /* If this is a shared link, reset backoff on success. * Otherwise, do so only is the queue is empty */ tsch_queue_backoff_reset(n); } } } else { /* Failed transmission */ if(p->transmissions >= TSCH_MAC_MAX_FRAME_RETRIES + 1) { /* Drop packet */ tsch_queue_remove_packet_from_queue(n); in_queue = 0; } /* Update CSMA state in the unicast case */ if(is_unicast) { /* Failures on dedicated (== non-shared) leave the backoff * window nor exponent unchanged */ if(is_shared_link) { /* Shared link: increment backoff exponent, pick a new window */ tsch_queue_backoff_inc(n); } } } return in_queue; } /*---------------------------------------------------------------------------*/ static PT_THREAD(tsch_tx_slot(struct pt *pt, struct rtimer *t)) { /** * TX slot: * 1. Copy packet to radio buffer * 2. Perform CCA if enabled * 3. Sleep until it is time to transmit * 4. Wait for ACK if it is a unicast packet * 5. Extract drift if we received an E-ACK from a time source neighbor * 6. Update CSMA parameters according to TX status * 7. Schedule mac_call_sent_callback **/ /* tx status */ static uint8_t mac_tx_status; /* is the packet in its neighbor's queue? */ uint8_t in_queue; static int dequeued_index; static int packet_ready = 1; PT_BEGIN(pt); TSCH_DEBUG_TX_EVENT(); /* First check if we have space to store a newly dequeued packet (in case of * successful Tx or Drop) */ dequeued_index = ringbufindex_peek_put(&dequeued_ringbuf); if(dequeued_index != -1) { if(current_packet == NULL || current_packet->qb == NULL) { mac_tx_status = MAC_TX_ERR_FATAL; } else { /* packet payload */ static void *packet; #if TSCH_SECURITY_ENABLED /* encrypted payload */ static uint8_t encrypted_packet[TSCH_PACKET_MAX_LEN]; #endif /* TSCH_SECURITY_ENABLED */ /* packet payload length */ static uint8_t packet_len; /* packet seqno */ static uint8_t seqno; /* is this a broadcast packet? (wait for ack?) */ static uint8_t is_broadcast; static rtimer_clock_t tx_start_time; #if CCA_ENABLED static uint8_t cca_status; #endif /* get payload */ packet = queuebuf_dataptr(current_packet->qb); packet_len = queuebuf_datalen(current_packet->qb); /* is this a broadcast packet? (wait for ack?) */ is_broadcast = current_neighbor->is_broadcast; /* read seqno from payload */ seqno = ((uint8_t *)(packet))[2]; /* if this is an EB, then update its Sync-IE */ if(current_neighbor == n_eb) { packet_ready = tsch_packet_update_eb(packet, packet_len, current_packet->tsch_sync_ie_offset); } else { packet_ready = 1; } #if TSCH_SECURITY_ENABLED if(tsch_is_pan_secured) { /* If we are going to encrypt, we need to generate the output in a separate buffer and keep * the original untouched. This is to allow for future retransmissions. */ int with_encryption = queuebuf_attr(current_packet->qb, PACKETBUF_ATTR_SECURITY_LEVEL) & 0x4; packet_len += tsch_security_secure_frame(packet, with_encryption ? encrypted_packet : packet, current_packet->header_len, packet_len - current_packet->header_len, ¤t_asn); if(with_encryption) { packet = encrypted_packet; } } #endif /* TSCH_SECURITY_ENABLED */ /* prepare packet to send: copy to radio buffer */ if(packet_ready && NETSTACK_RADIO.prepare(packet, packet_len) == 0) { /* 0 means success */ static rtimer_clock_t tx_duration; #if CCA_ENABLED cca_status = 1; /* delay before CCA */ TSCH_SCHEDULE_AND_YIELD(pt, t, current_slot_start, TS_CCA_OFFSET, "cca"); TSCH_DEBUG_TX_EVENT(); NETSTACK_RADIO.on(); /* CCA */ BUSYWAIT_UNTIL_ABS(!(cca_status |= NETSTACK_RADIO.channel_clear()), current_slot_start, TS_CCA_OFFSET + TS_CCA); TSCH_DEBUG_TX_EVENT(); /* there is not enough time to turn radio off */ /* NETSTACK_RADIO.off(); */ if(cca_status == 0) { mac_tx_status = MAC_TX_COLLISION; } else #endif /* CCA_ENABLED */ { /* delay before TX */ TSCH_SCHEDULE_AND_YIELD(pt, t, current_slot_start, tsch_timing[tsch_ts_tx_offset] - RADIO_DELAY_BEFORE_TX, "TxBeforeTx"); TSCH_DEBUG_TX_EVENT(); /* send packet already in radio tx buffer */ mac_tx_status = NETSTACK_RADIO.transmit(packet_len); /* Save tx timestamp */ tx_start_time = current_slot_start + tsch_timing[tsch_ts_tx_offset]; /* calculate TX duration based on sent packet len */ tx_duration = TSCH_PACKET_DURATION(packet_len); /* limit tx_time to its max value */ tx_duration = MIN(tx_duration, tsch_timing[tsch_ts_max_tx]); /* turn tadio off -- will turn on again to wait for ACK if needed */ NETSTACK_RADIO.off(); if(mac_tx_status == RADIO_TX_OK) { if(!is_broadcast) { uint8_t ackbuf[TSCH_PACKET_MAX_LEN]; int ack_len; rtimer_clock_t ack_start_time; int is_time_source; radio_value_t radio_rx_mode; struct ieee802154_ies ack_ies; uint8_t ack_hdrlen; frame802154_t frame; /* Entering promiscuous mode so that the radio accepts the enhanced ACK */ NETSTACK_RADIO.get_value(RADIO_PARAM_RX_MODE, &radio_rx_mode); NETSTACK_RADIO.set_value(RADIO_PARAM_RX_MODE, radio_rx_mode & (~RADIO_RX_MODE_ADDRESS_FILTER)); /* Unicast: wait for ack after tx: sleep until ack time */ TSCH_SCHEDULE_AND_YIELD(pt, t, current_slot_start, tsch_timing[tsch_ts_tx_offset] + tx_duration + tsch_timing[tsch_ts_rx_ack_delay] - RADIO_DELAY_BEFORE_RX, "TxBeforeAck"); TSCH_DEBUG_TX_EVENT(); NETSTACK_RADIO.on(); /* Wait for ACK to come */ BUSYWAIT_UNTIL_ABS(NETSTACK_RADIO.receiving_packet(), tx_start_time, tx_duration + tsch_timing[tsch_ts_rx_ack_delay] + tsch_timing[tsch_ts_ack_wait]); TSCH_DEBUG_TX_EVENT(); ack_start_time = RTIMER_NOW(); /* Wait for ACK to finish */ BUSYWAIT_UNTIL_ABS(!NETSTACK_RADIO.receiving_packet(), ack_start_time, tsch_timing[tsch_ts_max_ack]); TSCH_DEBUG_TX_EVENT(); NETSTACK_RADIO.off(); /* Leaving promiscuous mode */ NETSTACK_RADIO.get_value(RADIO_PARAM_RX_MODE, &radio_rx_mode); NETSTACK_RADIO.set_value(RADIO_PARAM_RX_MODE, radio_rx_mode | RADIO_RX_MODE_ADDRESS_FILTER); /* Read ack frame */ ack_len = NETSTACK_RADIO.read((void *)ackbuf, sizeof(ackbuf)); is_time_source = 0; /* The radio driver should return 0 if no valid packets are in the rx buffer */ if(ack_len > 0) { is_time_source = current_neighbor != NULL && current_neighbor->is_time_source; if(tsch_packet_parse_eack(ackbuf, ack_len, seqno, &frame, &ack_ies, &ack_hdrlen) == 0) { ack_len = 0; } #if TSCH_SECURITY_ENABLED if(ack_len != 0) { if(!tsch_security_parse_frame(ackbuf, ack_hdrlen, ack_len - ack_hdrlen - tsch_security_mic_len(&frame), &frame, ¤t_neighbor->addr, ¤t_asn)) { TSCH_LOG_ADD(tsch_log_message, snprintf(log->message, sizeof(log->message), "!failed to authenticate ACK")); ack_len = 0; } } else { TSCH_LOG_ADD(tsch_log_message, snprintf(log->message, sizeof(log->message), "!failed to parse ACK")); } #endif /* TSCH_SECURITY_ENABLED */ } if(ack_len != 0) { if(is_time_source) { int32_t eack_time_correction = US_TO_RTIMERTICKS(ack_ies.ie_time_correction); int32_t since_last_timesync = ASN_DIFF(current_asn, last_sync_asn); if(eack_time_correction > SYNC_IE_BOUND) { drift_correction = SYNC_IE_BOUND; } else if(eack_time_correction < -SYNC_IE_BOUND) { drift_correction = -SYNC_IE_BOUND; } else { drift_correction = eack_time_correction; } if(drift_correction != eack_time_correction) { TSCH_LOG_ADD(tsch_log_message, snprintf(log->message, sizeof(log->message), "!truncated dr %d %d", (int)eack_time_correction, (int)drift_correction); ); } is_drift_correction_used = 1; tsch_timesync_update(current_neighbor, since_last_timesync, drift_correction); /* Keep track of sync time */ last_sync_asn = current_asn; tsch_schedule_keepalive(); } mac_tx_status = MAC_TX_OK; } else { mac_tx_status = MAC_TX_NOACK; } } else { mac_tx_status = MAC_TX_OK; } } else { mac_tx_status = MAC_TX_ERR; } } } } current_packet->transmissions++; current_packet->ret = mac_tx_status; /* Post TX: Update neighbor state */ in_queue = update_neighbor_state(current_neighbor, current_packet, current_link, mac_tx_status); /* The packet was dequeued, add it to dequeued_ringbuf for later processing */ if(in_queue == 0) { dequeued_array[dequeued_index] = current_packet; ringbufindex_put(&dequeued_ringbuf); } /* Log every tx attempt */ TSCH_LOG_ADD(tsch_log_tx, log->tx.mac_tx_status = mac_tx_status; log->tx.num_tx = current_packet->transmissions; log->tx.datalen = queuebuf_datalen(current_packet->qb); log->tx.drift = drift_correction; log->tx.drift_used = is_drift_correction_used; log->tx.is_data = ((((uint8_t *)(queuebuf_dataptr(current_packet->qb)))[0]) & 7) == FRAME802154_DATAFRAME; log->tx.sec_level = queuebuf_attr(current_packet->qb, PACKETBUF_ATTR_SECURITY_LEVEL); log->tx.dest = TSCH_LOG_ID_FROM_LINKADDR(queuebuf_addr(current_packet->qb, PACKETBUF_ADDR_RECEIVER)); ); /* Poll process for later processing of packet sent events and logs */ process_poll(&tsch_pending_events_process); } TSCH_DEBUG_TX_EVENT(); PT_END(pt); } /*---------------------------------------------------------------------------*/ static PT_THREAD(tsch_rx_slot(struct pt *pt, struct rtimer *t)) { /** * RX slot: * 1. Check if it is used for TIME_KEEPING * 2. Sleep and wake up just before expected RX time (with a guard time: TS_LONG_GT) * 3. Check for radio activity for the guard time: TS_LONG_GT * 4. Prepare and send ACK if needed * 5. Drift calculated in the ACK callback registered with the radio driver. Use it if receiving from a time source neighbor. **/ struct tsch_neighbor *n; static linkaddr_t source_address; static linkaddr_t destination_address; static int16_t input_index; static int input_queue_drop = 0; PT_BEGIN(pt); TSCH_DEBUG_RX_EVENT(); input_index = ringbufindex_peek_put(&input_ringbuf); if(input_index == -1) { input_queue_drop++; } else { static struct input_packet *current_input; /* Estimated drift based on RX time */ static int32_t estimated_drift; /* Rx timestamps */ static rtimer_clock_t rx_start_time; static rtimer_clock_t expected_rx_time; static rtimer_clock_t packet_duration; uint8_t packet_seen; expected_rx_time = current_slot_start + tsch_timing[tsch_ts_tx_offset]; /* Default start time: expected Rx time */ rx_start_time = expected_rx_time; current_input = &input_array[input_index]; /* Wait before starting to listen */ TSCH_SCHEDULE_AND_YIELD(pt, t, current_slot_start, tsch_timing[tsch_ts_rx_offset] - RADIO_DELAY_BEFORE_RX, "RxBeforeListen"); TSCH_DEBUG_RX_EVENT(); /* Start radio for at least guard time */ NETSTACK_RADIO.on(); packet_seen = NETSTACK_RADIO.receiving_packet(); if(!packet_seen) { /* Check if receiving within guard time */ BUSYWAIT_UNTIL_ABS((packet_seen = NETSTACK_RADIO.receiving_packet()), current_slot_start, tsch_timing[tsch_ts_rx_offset] + tsch_timing[tsch_ts_rx_wait]); } if(packet_seen) { TSCH_DEBUG_RX_EVENT(); /* Save packet timestamp */ rx_start_time = RTIMER_NOW() - RADIO_DELAY_BEFORE_DETECT; } if(!NETSTACK_RADIO.receiving_packet() && !NETSTACK_RADIO.pending_packet()) { NETSTACK_RADIO.off(); /* no packets on air */ } else { /* Wait until packet is received, turn radio off */ BUSYWAIT_UNTIL_ABS(!NETSTACK_RADIO.receiving_packet(), current_slot_start, tsch_timing[tsch_ts_rx_offset] + tsch_timing[tsch_ts_rx_wait] + tsch_timing[tsch_ts_max_tx]); TSCH_DEBUG_RX_EVENT(); NETSTACK_RADIO.off(); #if TSCH_RESYNC_WITH_SFD_TIMESTAMPS /* At the end of the reception, get an more accurate estimate of SFD arrival time */ NETSTACK_RADIO.get_object(RADIO_PARAM_LAST_PACKET_TIMESTAMP, &rx_start_time, sizeof(rtimer_clock_t)); #endif if(NETSTACK_RADIO.pending_packet()) { static int frame_valid; static int header_len; static frame802154_t frame; radio_value_t radio_last_rssi; NETSTACK_RADIO.get_value(RADIO_PARAM_LAST_RSSI, &radio_last_rssi); /* Read packet */ current_input->len = NETSTACK_RADIO.read((void *)current_input->payload, TSCH_PACKET_MAX_LEN); current_input->rx_asn = current_asn; current_input->rssi = (signed)radio_last_rssi; header_len = frame802154_parse((uint8_t *)current_input->payload, current_input->len, &frame); frame_valid = header_len > 0 && frame802154_check_dest_panid(&frame) && frame802154_extract_linkaddr(&frame, &source_address, &destination_address); packet_duration = TSCH_PACKET_DURATION(current_input->len); #if TSCH_SECURITY_ENABLED /* Decrypt and verify incoming frame */ if(frame_valid) { if(tsch_security_parse_frame( current_input->payload, header_len, current_input->len - header_len - tsch_security_mic_len(&frame), &frame, &source_address, ¤t_asn)) { current_input->len -= tsch_security_mic_len(&frame); } else { TSCH_LOG_ADD(tsch_log_message, snprintf(log->message, sizeof(log->message), "!failed to authenticate frame %u", current_input->len)); frame_valid = 0; } } else { TSCH_LOG_ADD(tsch_log_message, snprintf(log->message, sizeof(log->message), "!failed to parse frame %u %u", header_len, current_input->len)); frame_valid = 0; } #endif /* TSCH_SECURITY_ENABLED */ if(frame_valid) { if(linkaddr_cmp(&destination_address, &linkaddr_node_addr) || linkaddr_cmp(&destination_address, &linkaddr_null)) { int do_nack = 0; estimated_drift = ((int32_t)expected_rx_time - (int32_t)rx_start_time); #if TSCH_TIMESYNC_REMOVE_JITTER /* remove jitter due to measurement errors */ if(abs(estimated_drift) <= TSCH_TIMESYNC_MEASUREMENT_ERROR) { estimated_drift = 0; } else if(estimated_drift > 0) { estimated_drift -= TSCH_TIMESYNC_MEASUREMENT_ERROR; } else { estimated_drift += TSCH_TIMESYNC_MEASUREMENT_ERROR; } #endif #ifdef TSCH_CALLBACK_DO_NACK if(frame.fcf.ack_required) { do_nack = TSCH_CALLBACK_DO_NACK(current_link, &source_address, &destination_address); } #endif if(frame.fcf.ack_required) { static uint8_t ack_buf[TSCH_PACKET_MAX_LEN]; static int ack_len; /* Build ACK frame */ ack_len = tsch_packet_create_eack(ack_buf, sizeof(ack_buf), &source_address, frame.seq, (int16_t)RTIMERTICKS_TO_US(estimated_drift), do_nack); #if TSCH_SECURITY_ENABLED if(tsch_is_pan_secured) { /* Secure ACK frame. There is only header and header IEs, therefore data len == 0. */ ack_len += tsch_security_secure_frame(ack_buf, ack_buf, ack_len, 0, ¤t_asn); } #endif /* TSCH_SECURITY_ENABLED */ /* Copy to radio buffer */ NETSTACK_RADIO.prepare((const void *)ack_buf, ack_len); /* Wait for time to ACK and transmit ACK */ TSCH_SCHEDULE_AND_YIELD(pt, t, rx_start_time, packet_duration + tsch_timing[tsch_ts_tx_ack_delay] - RADIO_DELAY_BEFORE_TX, "RxBeforeAck"); TSCH_DEBUG_RX_EVENT(); NETSTACK_RADIO.transmit(ack_len); } /* If the sender is a time source, proceed to clock drift compensation */ n = tsch_queue_get_nbr(&source_address); if(n != NULL && n->is_time_source) { int32_t since_last_timesync = ASN_DIFF(current_asn, last_sync_asn); /* Keep track of last sync time */ last_sync_asn = current_asn; /* Save estimated drift */ drift_correction = -estimated_drift; is_drift_correction_used = 1; tsch_timesync_update(n, since_last_timesync, -estimated_drift); tsch_schedule_keepalive(); } /* Add current input to ringbuf */ ringbufindex_put(&input_ringbuf); /* Log every reception */ TSCH_LOG_ADD(tsch_log_rx, log->rx.src = TSCH_LOG_ID_FROM_LINKADDR((linkaddr_t*)&frame.src_addr); log->rx.is_unicast = frame.fcf.ack_required; log->rx.datalen = current_input->len; log->rx.drift = drift_correction; log->rx.drift_used = is_drift_correction_used; log->rx.is_data = frame.fcf.frame_type == FRAME802154_DATAFRAME; log->rx.sec_level = frame.aux_hdr.security_control.security_level; log->rx.estimated_drift = estimated_drift; ); } else { TSCH_LOG_ADD(tsch_log_message, snprintf(log->message, sizeof(log->message), "!not for us %x:%x:%x:%x", destination_address.u8[4], destination_address.u8[5], destination_address.u8[6], destination_address.u8[7]); ); } /* Poll process for processing of pending input and logs */ process_poll(&tsch_pending_events_process); } } } if(input_queue_drop != 0) { TSCH_LOG_ADD(tsch_log_message, snprintf(log->message, sizeof(log->message), "!queue full skipped %u", input_queue_drop); ); input_queue_drop = 0; } } TSCH_DEBUG_RX_EVENT(); PT_END(pt); } /*---------------------------------------------------------------------------*/ /* Protothread for slot operation, called from rtimer interrupt * and scheduled from tsch_schedule_slot_operation */ static PT_THREAD(tsch_slot_operation(struct rtimer *t, void *ptr)) { TSCH_DEBUG_INTERRUPT(); PT_BEGIN(&slot_operation_pt); /* Loop over all active slots */ while(tsch_is_associated) { if(current_link == NULL || tsch_lock_requested) { /* Skip slot operation if there is no link or if there is a pending request for getting the lock */ /* Issue a log whenever skipping a slot */ TSCH_LOG_ADD(tsch_log_message, snprintf(log->message, sizeof(log->message), "!skipped slot %u %u %u", tsch_locked, tsch_lock_requested, current_link == NULL); ); } else { uint8_t current_channel; TSCH_DEBUG_SLOT_START(); tsch_in_slot_operation = 1; /* Get a packet ready to be sent */ current_packet = get_packet_and_neighbor_for_link(current_link, ¤t_neighbor); /* There is no packet to send, and this link does not have Rx flag. Instead of doing * nothing, switch to the backup link (has Rx flag) if any. */ if(current_packet == NULL && !(current_link->link_options & LINK_OPTION_RX) && backup_link != NULL) { current_link = backup_link; current_packet = get_packet_and_neighbor_for_link(current_link, ¤t_neighbor); } /* Hop channel */ current_channel = tsch_calculate_channel(¤t_asn, current_link->channel_offset); NETSTACK_RADIO.set_value(RADIO_PARAM_CHANNEL, current_channel); /* Reset drift correction */ drift_correction = 0; is_drift_correction_used = 0; /* Decide whether it is a TX/RX/IDLE or OFF slot */ /* Actual slot operation */ if(current_packet != NULL) { /* We have something to transmit, do the following: * 1. send * 2. update_backoff_state(current_neighbor) * 3. post tx callback **/ static struct pt slot_tx_pt; PT_SPAWN(&slot_operation_pt, &slot_tx_pt, tsch_tx_slot(&slot_tx_pt, t)); } else if((current_link->link_options & LINK_OPTION_RX)) { /* Listen */ static struct pt slot_rx_pt; PT_SPAWN(&slot_operation_pt, &slot_rx_pt, tsch_rx_slot(&slot_rx_pt, t)); } TSCH_DEBUG_SLOT_END(); } /* End of slot operation, schedule next slot or resynchronize */ /* Do we need to resynchronize? i.e., wait for EB again */ if(!tsch_is_coordinator && (ASN_DIFF(current_asn, last_sync_asn) > (100 * TSCH_CLOCK_TO_SLOTS(TSCH_DESYNC_THRESHOLD / 100, tsch_timing[tsch_ts_timeslot_length])))) { TSCH_LOG_ADD(tsch_log_message, snprintf(log->message, sizeof(log->message), "! leaving the network, last sync %u", (unsigned)ASN_DIFF(current_asn, last_sync_asn)); ); last_timesource_neighbor = NULL; tsch_disassociate(); } else { /* backup of drift correction for printing debug messages */ /* int32_t drift_correction_backup = drift_correction; */ uint16_t timeslot_diff = 0; rtimer_clock_t prev_slot_start; /* Time to next wake up */ rtimer_clock_t time_to_next_active_slot; /* Schedule next wakeup skipping slots if missed deadline */ do { if(current_link != NULL && current_link->link_options & LINK_OPTION_TX && current_link->link_options & LINK_OPTION_SHARED) { /* Decrement the backoff window for all neighbors able to transmit over * this Tx, Shared link. */ tsch_queue_update_all_backoff_windows(¤t_link->addr); } /* Get next active link */ current_link = tsch_schedule_get_next_active_link(¤t_asn, ×lot_diff, &backup_link); if(current_link == NULL) { /* There is no next link. Fall back to default * behavior: wake up at the next slot. */ timeslot_diff = 1; } /* Update ASN */ ASN_INC(current_asn, timeslot_diff); /* Time to next wake up */ time_to_next_active_slot = timeslot_diff * tsch_timing[tsch_ts_timeslot_length] + drift_correction; drift_correction = 0; is_drift_correction_used = 0; /* Update current slot start */ prev_slot_start = current_slot_start; current_slot_start += time_to_next_active_slot; current_slot_start += tsch_timesync_adaptive_compensate(time_to_next_active_slot); } while(!tsch_schedule_slot_operation(t, prev_slot_start, time_to_next_active_slot, "main")); } tsch_in_slot_operation = 0; PT_YIELD(&slot_operation_pt); } PT_END(&slot_operation_pt); } /*---------------------------------------------------------------------------*/ /* Set global time before starting slot operation, * with a rtimer time and an ASN */ void tsch_slot_operation_start(void) { static struct rtimer slot_operation_timer; rtimer_clock_t time_to_next_active_slot; rtimer_clock_t prev_slot_start; TSCH_DEBUG_INIT(); do { uint16_t timeslot_diff; /* Get next active link */ current_link = tsch_schedule_get_next_active_link(¤t_asn, ×lot_diff, &backup_link); if(current_link == NULL) { /* There is no next link. Fall back to default * behavior: wake up at the next slot. */ timeslot_diff = 1; } /* Update ASN */ ASN_INC(current_asn, timeslot_diff); /* Time to next wake up */ time_to_next_active_slot = timeslot_diff * tsch_timing[tsch_ts_timeslot_length]; /* Update current slot start */ prev_slot_start = current_slot_start; current_slot_start += time_to_next_active_slot; } while(!tsch_schedule_slot_operation(&slot_operation_timer, prev_slot_start, time_to_next_active_slot, "association")); } /*---------------------------------------------------------------------------*/ /* Start actual slot operation */ void tsch_slot_operation_sync(rtimer_clock_t next_slot_start, struct asn_t *next_slot_asn) { current_slot_start = next_slot_start; current_asn = *next_slot_asn; last_sync_asn = current_asn; current_link = NULL; } /*---------------------------------------------------------------------------*/