bsd/netinet/tcp_timer.c

179 /* This parameter determines how long the timer list will stay in fast mode even
180  * though all connections are idle. In fast mode, the timer will fire more frequently
206     "Number of times timer list was rescheduled as part of processing a packet");
223 /* TCP delack timer is set to 100 ms. Since the processing of timer list in fast
224  * mode will happen no faster than 100 ms, the delayed ack timer will fire some where
232 /* tcp timer list */
235 /* The frequency of running through the TCP timer list in
240 	"Frequency of running timer list in fast mode");
244 	"Frequency of running timer list in slow mode");
253  * safe to assume that the timer has wrapped around. By doing signed comparision,
263 /* Returns true if the timer is on the timer list */
276 	uint32_t timer;
288 	 * we need to recalculate the TCPT_2MSL timer value for tcp_slowtimo
289 	 * higher timer granularity.
292 	timer = (delay / TCP_RETRANSHZ) * PR_SLOWHZ;
295 	tp->t_rcvtime += timer & (N_TIME_WAIT_SLOTS - 1);
297 	tw_slot = (timer & (N_TIME_WAIT_SLOTS - 1)) + cur_tw_slot;
391 		/* If this tp still happens to be on the timer list,
431 	/* Update tcp_now here as it may get used while processing the slow timer */
532  * TCP timer processing.
535 tcp_timers(tp, timer)
537 	int timer;
556 	switch (timer) {
580 	 * Retransmission timer went off.  Message has not
585 		/* Drop a connection in the retransmit timer
750 		 * If timing a segment in this window, stop the timer.
775 	 * Persistance timer into zero window.
810 	 * Keep-alive timer went off; send something
867 			/* If delayed ack timer fired while we are stretching acks,
901 /* Remove a timer entry from timer list */
913 	/* Check if pcb is on timer list again after acquiring the lock */
933  * the timer entry correctly. Basically, this is to check if we can avoid
956 		/* The list is going to run before this timer */
989  * Returns the offset of next timer to be run for this connection which
1020         /* Since the timer thread needs to wait for tcp lock, it may race
1021          * with another thread that can cancel or reschedule the timer that is
1047 	 * adjust the timer values wrt tcp_now.
1139 			/* Some how this pcb went into dead state while on the timer list,
1140 			 * just take it off the list. Since the timer list entry pointers
1141 			 * are protected by the timer list lock, we can do it here
1220 		/* No need to reschedule this timer */
1231 /* Function to verify if a change in timer state is required for a connection */
1284 	/* timer entry is currently on the list */
1307 				/* The list is going to run before this timer */