NEIGH_VAR_BASE_REACHABLE_TIME
t->neigh_vars[NEIGH_VAR_BASE_REACHABLE_TIME].proc_handler = handler;
t->neigh_vars[NEIGH_VAR_BASE_REACHABLE_TIME].proc_handler =
[NEIGH_VAR_BASE_REACHABLE_TIME] = 30 * HZ,
[NEIGH_VAR_BASE_REACHABLE_TIME] = ND_REACHABLE_TIME,