if_foreach_sleep
if_foreach_sleep(NULL, NULL, linsysfs_net_addif, net);
int if_foreach_sleep(if_foreach_match_t, void *, if_foreach_cb_t, void *);
if_foreach_sleep(NULL, NULL, ng_ether_attach, NULL);
if_foreach_sleep(ipsec_accel_sa_install_match, context,
if_foreach_sleep(ipsec_accel_spdadd_match, arg,
if_foreach_sleep(match_iface, &attrs, dump_cb, &wa);