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Implement RPL probing

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This commit is contained in:
Simon Duquennoy 2015-05-06 11:35:42 +02:00
parent 529376be77
commit 47ba4c0c4b
7 changed files with 155 additions and 6 deletions
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85
core/net/rpl/rpl-timers.c
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@ -327,5 +327,90 @@ rpl_cancel_dao(rpl_instance_t *instance)
ctimer_stop(&instance->dao_lifetime_timer);
}
/*---------------------------------------------------------------------------*/
#if RPL_WITH_PROBING
static rpl_parent_t *
get_probing_target(rpl_dag_t *dag)
{
/* Returns the next probing target. The current implementation looks for the
* best parent to which we have not transmitted since 2 * RPL_PROBING_INTERVAL.
* This will mostly select the preferred and second best parents. Probing the
* second best parent is important: if the link is good, RPL might choose to
* switch to it. If the link is bad, the second best parent will decrease in
* ranking, and another parent will be probed next time. */
rpl_parent_t *p;
rpl_parent_t *probing_target;
rpl_rank_t probing_target_rank;
/* Look for a parent we have not sent to since 2 * RPL_PROBING_INTERVAL,
* e.g. with last_tx_time earlier than min_last_tx */
clock_time_t min_last_tx = clock_time();
min_last_tx = min_last_tx > 2 * RPL_PROBING_INTERVAL ? min_last_tx - 2 * RPL_PROBING_INTERVAL : 1;
if(dag == NULL ||
dag->instance == NULL ||
dag->preferred_parent == NULL) {
return NULL;
}
/* Our preferred parent needs probing */
if(dag->preferred_parent->last_tx_time < min_last_tx) {
return dag->preferred_parent;
}
/* Look for the best parent that needs probing. */
probing_target = NULL;
probing_target_rank = INFINITE_RANK;
p = nbr_table_head(rpl_parents);
while(p != NULL) {
if(p->dag == dag && p->last_tx_time < min_last_tx) {
rpl_rank_t p_rank = dag->instance->of->calculate_rank(p, 0);
/* p is in our dag and needs probing */
if(probing_target == NULL) {
probing_target = p;
probing_target_rank = p_rank;
} else {
if(p_rank < probing_target_rank) {
/* Found better candidate */
probing_target = p;
probing_target_rank = p_rank;
}
}
}
p = nbr_table_next(rpl_parents, p);
}
return probing_target;
}
/*---------------------------------------------------------------------------*/
static void
handle_probing_timer(void *ptr)
{
rpl_instance_t *instance = (rpl_instance_t *)ptr;
rpl_parent_t *probing_target = RPL_PROBING_SELECT_FUNC(instance->current_dag);
/* Perform probing */
if(probing_target != NULL && rpl_get_parent_ipaddr(probing_target) != NULL) {
PRINTF("RPL: probing %3u\n",
nbr_table_get_lladdr(rpl_parents, probing_target)->u8[7]);
/* Send probe, e.g. unicast DIO or DIS */
RPL_PROBING_SEND_FUNC(instance, rpl_get_parent_ipaddr(probing_target));
}
/* Schedule next probing */
rpl_schedule_probing(instance);
#if DEBUG
rpl_print_neighbor_list();
#endif
}
/*---------------------------------------------------------------------------*/
void
rpl_schedule_probing(rpl_instance_t *instance)
{
clock_time_t delay = (RPL_PROBING_INTERVAL / 2) +
random_rand() % (RPL_PROBING_INTERVAL / 2);
ctimer_set(&instance->probing_timer, delay,
handle_probing_timer, instance);
}
#endif /* RPL_WITH_PROBING */
/** @}*/