Title: clck_timer()


clck_timer(timer, timeout, func, fd) configures timer, clck_timer()'s first parameter, based on timeout, func, and fd (clck_timer()'s second, third, and fourth parameters) and places the timer in its appropriate position in timer_chain. In other words, if the new timer is scheduled to expire before any other timer, it is inserted at the head of the linked list and if the new timer is scheduled to expire after all the other timers, it is inserted at the tail of the linked list. If the new timer is scheduled to expire before any other timers, clck_timer() calls set_timer(), which sends a message to the clock task with a revised expiration time for the synchronous alarm.

An example of a client calling clck_timer() to insert a timer in timer_chain is the arp client.