| RT_TIMER(9) | Kernel Developer's Manual | RT_TIMER(9) | 
rt_timer, rt_timer_add,
  rt_timer_queue_create,
  rt_timer_queue_change,
  rt_timer_queue_destroy,
  rt_timer_remove_all —
#include <net/route.h>
struct rttimer_queue *
  
  rt_timer_queue_create(time_t
    timeout);
void
  
  rt_timer_queue_change(struct
    rttimer_queue *q, time_t
    timeout);
void
  
  rt_timer_queue_destroy(struct
    rttimer_queue *q, int
    destroy);
int
  
  rt_timer_add(struct
    rtentry *rt,
    void(*f)(struct rtentry *,
    struct rttimer *), struct
    rttimer_queue *q);
void
  
  rt_timer_remove_all(struct
    rtentry *rt);
rt_timer functions provide a generic route callout
  functionality. They allow a function to be called for a route at any time.
  This was originally intended to be used to remove routes added by path MTU
  discovery code.
For maximum efficiency, a separate queue should be defined for each timeout period. For example, one queue should be created for the 10 minute path MTU discovery timeouts, another for 20 minute ARP timeouts after 20 minutes, and so on. This permits extremely fast queue manipulations so that the timeout functions remain scalable, even in the face of thousands of route manipulations per minute.
It is possible to create only a single timeout queue for all possible timeout values, but doing so is not scalable as queue manipulations become quite expensive if the timeout deltas are not roughly constant.
The rt_timer interface provides the
    following functions:
rt_timer_queue_create(time_t
    timeout)rt_timer_queue_change(rttimer_queue
    *q, time_t timeout)rt_timer_queue_destroy(rttimer_queue
    *q, int destroy)rt_timer_add(struct rtentry
    *rt, void(*f)(struct rtentry *, struct rttimer
    *), struct rttimer_queue *q)rt_timer_remove_all(struct rtentry
    *rt)rt_timer subsystem. This is used when a route is
      deleted to ensure that no dangling references remain.rt_timer interface is implemented in
  sys/net/route.h and
  sys/net/route.c.
rt_timer interface appeared in
  NetBSD 1.4.
| June 1, 2016 | NetBSD 9.4 |