/* Prepare and send a keepalive message */
static void
keepalive_send()
{
if(tsch_is_associated) {
struct tsch_neighbor *n = tsch_queue_get_time_source();
/* Simply send an empty packet */
packetbuf_clear();
packetbuf_set_addr(PACKETBUF_ADDR_RECEIVER, &n->addr);
NETSTACK_LLSEC.send(keepalive_packet_sent, NULL);
PRINTF("TSCH: sending KA to %u\n",
TSCH_LOG_ID_FROM_LINKADDR(&n->addr));
}
}
/* Update TSCH time source */
int
tsch_queue_update_time_source(const linkaddr_t *new_addr)
{
if(!tsch_is_locked()) {
if(!tsch_is_coordinator) {
struct tsch_neighbor *old_time_src = tsch_queue_get_time_source();
struct tsch_neighbor *new_time_src = NULL;
if(new_addr != NULL) {
/* Get/add neighbor, return 0 in case of failure */
new_time_src = tsch_queue_add_nbr(new_addr);
if(new_time_src == NULL) {
return 0;
}
}
if(new_time_src != old_time_src) {
PRINTF("TSCH: update time source: %u -> %u\n",
TSCH_LOG_ID_FROM_LINKADDR(old_time_src ? &old_time_src->addr : NULL),
TSCH_LOG_ID_FROM_LINKADDR(new_time_src ? &new_time_src->addr : NULL));
/* Update time source */
if(new_time_src != NULL) {
new_time_src->is_time_source = 1;
/* (Re)set keep-alive timeout */
tsch_set_ka_timeout(TSCH_KEEPALIVE_TIMEOUT);
/* Start sending keepalives */
tsch_schedule_keepalive();
} else {
/* Stop sending keepalives */
tsch_set_ka_timeout(0);
}
if(old_time_src != NULL) {
old_time_src->is_time_source = 0;
}
#ifdef TSCH_CALLBACK_NEW_TIME_SOURCE
TSCH_CALLBACK_NEW_TIME_SOURCE(old_time_src, new_time_src);
#endif
}
return 1;
}
}
return 0;
}
/* Update TSCH time source */
int
tsch_queue_update_time_source(const linkaddr_t *new_addr)
{
if(!tsch_is_locked()) {
if(!tsch_is_coordinator) {
struct tsch_neighbor *old_time_src = tsch_queue_get_time_source();
struct tsch_neighbor *new_time_src = NULL;
if(new_addr != NULL) {
/* Get/add neighbor, return 0 in case of failure */
new_time_src = tsch_queue_add_nbr(new_addr);
if(new_time_src == NULL) {
return 0;
}
}
if(new_time_src != old_time_src) {
PRINTF("TSCH: update time source: %u -> %u\n",
TSCH_LOG_ID_FROM_LINKADDR(old_time_src ? &old_time_src->addr : NULL),
TSCH_LOG_ID_FROM_LINKADDR(new_time_src ? &new_time_src->addr : NULL));
/* Update time source */
if(new_time_src != NULL) {
new_time_src->is_time_source = 1;
}
if(old_time_src != NULL) {
old_time_src->is_time_source = 0;
}
#ifdef TSCH_CALLBACK_NEW_TIME_SOURCE
TSCH_CALLBACK_NEW_TIME_SOURCE(old_time_src, new_time_src);
#endif
}
return 1;
}
}
return 0;
}
/*---------------------------------------------------------------------------*/
static void
eb_input(struct input_packet *current_input)
{
/* PRINTF("TSCH: EB received\n"); */
frame802154_t frame;
/* Verify incoming EB (does its ASN match our Rx time?),
* and update our join priority. */
struct ieee802154_ies eb_ies;
if(tsch_packet_parse_eb(current_input->payload, current_input->len,
&frame, &eb_ies, NULL, 1)) {
/* PAN ID check and authentication done at rx time */
#if TSCH_AUTOSELECT_TIME_SOURCE
if(!tsch_is_coordinator) {
/* Maintain EB received counter for every neighbor */
struct eb_stat *stat = (struct eb_stat *)nbr_table_get_from_lladdr(eb_stats, &frame.src_addr);
if(stat == NULL) {
stat = (struct eb_stat *)nbr_table_add_lladdr(eb_stats, &frame.src_addr);
}
if(stat != NULL) {
stat->rx_count++;
stat->jp = eb_ies.join_priority;
best_neighbor_eb_count = MAX(best_neighbor_eb_count, stat->rx_count);
}
/* Select best time source */
struct eb_stat *best_stat = NULL;
stat = nbr_table_head(eb_stats);
while(stat != NULL) {
/* Is neighbor eligible as a time source? */
if(stat->rx_count > best_neighbor_eb_count / 2) {
if(best_stat == NULL ||
stat->jp < best_stat->jp) {
best_stat = stat;
}
}
stat = nbr_table_next(eb_stats, stat);
}
/* Update time source */
if(best_stat != NULL) {
tsch_queue_update_time_source(nbr_table_get_lladdr(eb_stats, best_stat));
tsch_join_priority = best_stat->jp + 1;
}
}
#endif
struct tsch_neighbor *n = tsch_queue_get_time_source();
/* Did the EB come from our time source? */
if(n != NULL && linkaddr_cmp((linkaddr_t *)&frame.src_addr, &n->addr)) {
/* Check for ASN drift */
int32_t asn_diff = ASN_DIFF(current_input->rx_asn, eb_ies.ie_asn);
if(asn_diff != 0) {
/* We disagree with our time source's ASN -- leave the network */
PRINTF("TSCH:! ASN drifted by %ld, leaving the network\n", asn_diff);
tsch_disassociate();
}
if(eb_ies.ie_join_priority >= TSCH_MAX_JOIN_PRIORITY) {
/* Join priority unacceptable. Leave network. */
PRINTF("TSCH:! EB JP too high %u, leaving the network\n",
eb_ies.ie_join_priority);
tsch_disassociate();
} else {
#if TSCH_AUTOSELECT_TIME_SOURCE
/* Update join priority */
if(tsch_join_priority != eb_ies.ie_join_priority + 1) {
PRINTF("TSCH: update JP from EB %u -> %u\n",
tsch_join_priority, eb_ies.ie_join_priority + 1);
tsch_join_priority = eb_ies.ie_join_priority + 1;
}
#endif /* TSCH_AUTOSELECT_TIME_SOURCE */
}
}
}
}
