void gnrc_sixlowpan_nd_init(gnrc_ipv6_netif_t *iface)
{
assert(iface->flags & GNRC_IPV6_NETIF_FLAGS_SIXLOWPAN);
mutex_lock(&iface->mutex);
iface->rtr_sol_count = 0; /* first will be sent immediately */
DEBUG("6lo nd: retransmit multicast rtr sol in 10 sec\n");
_rtr_sol_reschedule(iface, GNRC_SIXLOWPAN_ND_RTR_SOL_INT);
mutex_unlock(&iface->mutex);
gnrc_ndp_internal_send_rtr_sol(iface->pid, NULL);
}
void gnrc_ndp_host_retrans_rtr_sol(gnrc_ipv6_netif_t *iface)
{
mutex_lock(&iface->mutex);
if (iface->rtr_sol_count > 1) { /* regard off-by-one error */
DEBUG("ndp hst: retransmit rtr sol in %d sec\n", GNRC_NDP_MAX_RTR_SOL_INT);
iface->rtr_sol_count--;
_reschedule_rtr_sol(iface, GNRC_NDP_MAX_RTR_SOL_INT * US_PER_SEC);
}
mutex_unlock(&iface->mutex);
gnrc_ndp_internal_send_rtr_sol(iface->pid, NULL);
}
void gnrc_sixlowpan_nd_uc_rtr_sol(gnrc_ipv6_nc_t *nce)
{
assert(gnrc_ipv6_netif_get(nce->iface)->flags & GNRC_IPV6_NETIF_FLAGS_SIXLOWPAN);
/* neighbor is not a router anymore */
if (!(nce->flags & GNRC_IPV6_NC_IS_ROUTER) || ipv6_addr_is_unspecified(&nce->ipv6_addr)) {
/* and there are no routers anymore */
if (gnrc_ipv6_nc_get_next_router(NULL) == NULL) {
/* start search for routers */
gnrc_sixlowpan_nd_init(gnrc_ipv6_netif_get(nce->iface));
}
/* otherwise ignore this call */
return;
}
/* next RS is rescheduled by RA handle function */
gnrc_ndp_internal_send_rtr_sol(nce->iface, &nce->ipv6_addr);
}
void gnrc_sixlowpan_nd_mc_rtr_sol(gnrc_ipv6_netif_t *iface)
{
uint32_t interval;
assert(iface->flags & GNRC_IPV6_NETIF_FLAGS_SIXLOWPAN);
mutex_lock(&iface->mutex);
if (iface->rtr_sol_count < GNRC_NDP_MAX_RTR_SOL_NUMOF) {
DEBUG("6lo nd: retransmit multicast rtr sol in 10 sec\n");
iface->rtr_sol_count++;
interval = GNRC_SIXLOWPAN_ND_RTR_SOL_INT;
}
else {
unsigned int exp = (unsigned int)(iface->rtr_sol_count - GNRC_NDP_MAX_RTR_SOL_NUMOF);
interval = _binary_exp_backoff(1, exp);
if ((1U << exp) < GNRC_SIXLOWPAN_ND_MAX_RTR_SOL_INT) {
/* XXX Not sure if this is the correct interpretation of the truncation described in
* https://tools.ietf.org/html/rfc6775#section-5.3. In every source I've read the
* truncating value was the exponent, not the target value, so I'm very confused
* about this sentencing. Anyway, since 60 sec is a maximum value this should only
* affect the energy consumption of the implementation by sending the next RS too fast
* but not its interoperability. */
iface->rtr_sol_count++;
}
/* RFC6775, section 5.3 (https://tools.ietf.org/html/rfc6775#section-5.3)
* states that router solicitation should be sent slower after the
* initial 3 retransmissions (i.e. >= 10 secondes) and truncate "the
* increase of the retransmission timer at 60 seconds". */
if (interval < GNRC_SIXLOWPAN_ND_RTR_SOL_INT) {
interval = GNRC_SIXLOWPAN_ND_RTR_SOL_INT;
}
else if (interval > GNRC_SIXLOWPAN_ND_MAX_RTR_SOL_INT) {
interval = GNRC_SIXLOWPAN_ND_MAX_RTR_SOL_INT;
}
DEBUG("6lo nd: retransmit multicast rtr sol in %" PRIu32 " sec\n", interval);
}
_rtr_sol_reschedule(iface, interval);
mutex_unlock(&iface->mutex);
gnrc_ndp_internal_send_rtr_sol(iface->pid, NULL);
}
