retry.h File Reference

Retry timers. More...

#include <gpxe/list.h>

Go to the source code of this file.

Data Structures
struct	retry_timer
	A retry timer. More...
Defines
#define	DEFAULT_MIN_TIMEOUT   ( TICKS_PER_SEC / 4 )
	Default timeout value.
#define	DEFAULT_MAX_TIMEOUT   ( 10 * TICKS_PER_SEC )
	Limit after which the timeout will be deemed permanent.
Functions
	FILE_LICENCE (GPL2_OR_LATER)
void	start_timer (struct retry_timer *timer)
	Start timer.
void	start_timer_fixed (struct retry_timer *timer, unsigned long timeout)
	Start timer with a specified fixed timeout.
void	stop_timer (struct retry_timer *timer)
	Stop timer.
static void	start_timer_nodelay (struct retry_timer *timer)
	Start timer with no delay.
static	__attribute__ ((always_inline)) unsigned long timer_running(struct retry_timer *timer)
	Test to see if timer is currently running.

---

Detailed Description

Retry timers.

Definition in file retry.h.

---

Define Documentation

#define DEFAULT_MIN_TIMEOUT   ( TICKS_PER_SEC / 4 )

Default timeout value.

Definition at line 15 of file retry.h.

Referenced by start_timer().

#define DEFAULT_MAX_TIMEOUT   ( 10 * TICKS_PER_SEC )

Limit after which the timeout will be deemed permanent.

Definition at line 18 of file retry.h.

Referenced by timer_expired().

---

Function Documentation

FILE_LICENCE

(

GPL2_OR_LATER

)

void start_timer

(

struct retry_timer *

timer

)

Start timer.

Parameters:

timer

Retry timer

This starts the timer running with the current timeout value. If stop_timer() is not called before the timer expires, the timer will be stopped and the timer's callback function will be called.

Definition at line 59 of file retry.c.

References currticks(), DBG2, DEFAULT_MIN_TIMEOUT, retry_timer::list, list_add, MIN_TIMEOUT, retry_timer::min_timeout, retry_timer::running, retry_timer::start, and retry_timer::timeout.

Referenced by aoe_send_command(), dhcp_tx(), dns_send_packet(), ib_mi_timer_expired(), ipv4_reassemble(), slam_master_timer_expired(), slam_slave_timer_expired(), slam_socket_deliver(), start_timer_fixed(), tcp_rx(), tcp_xmit(), and tftp_send_packet().

                                               {
        if ( ! timer->running )
                list_add ( &timer->list, &timers );
        timer->start = currticks();
        timer->running = 1;

        /* 0 means "use default timeout" */
        if ( timer->min_timeout == 0 )
                timer->min_timeout = DEFAULT_MIN_TIMEOUT;
        /* We must never be less than MIN_TIMEOUT under any circumstances */
        if ( timer->min_timeout < MIN_TIMEOUT )
                timer->min_timeout = MIN_TIMEOUT;
        /* Honor user-specified minimum timeout */
        if ( timer->timeout < timer->min_timeout )
                timer->timeout = timer->min_timeout;

        DBG2 ( "Timer %p started at time %ld (expires at %ld)\n",
               timer, timer->start, ( timer->start + timer->timeout ) );
}

void start_timer_fixed	(	struct retry_timer *	timer,
		unsigned long	timeout
	)

Start timer with a specified fixed timeout.

Parameters:

	timer	Retry timer
	timeout	Timeout, in ticks

Definition at line 85 of file retry.c.

References DBG2, retry_timer::start, start_timer(), and retry_timer::timeout.

Referenced by slam_mc_socket_deliver(), slam_open(), and start_timer_nodelay().

                                                                            {
        start_timer ( timer );
        timer->timeout = timeout;
        DBG2 ( "Timer %p expiry time changed to %ld\n",
               timer, ( timer->start + timer->timeout ) );
}

void stop_timer

(

struct retry_timer *

timer

)

Stop timer.

Parameters:

timer

Retry timer

This stops the timer and updates the timer's timeout value.

Definition at line 99 of file retry.c.

References retry_timer::count, currticks(), DBG, DBG2, retry_timer::list, list_del, retry_timer::running, retry_timer::start, and retry_timer::timeout.

Referenced by aoe_detach(), aoe_done(), aoe_rx_ata(), dhcp_finished(), dhcp_set_state(), dns_done(), dns_xfer_deliver_raw(), ib_destroy_madx(), slam_finished(), slam_mc_socket_deliver(), slam_socket_deliver(), tcp_close(), tcp_rx_ack(), tftp_done(), and tftp_send_packet().

                                              {
        unsigned long old_timeout = timer->timeout;
        unsigned long now = currticks();
        unsigned long runtime;

        /* If timer was already stopped, do nothing */
        if ( ! timer->running )
                return;

        list_del ( &timer->list );
        runtime = ( now - timer->start );
        timer->running = 0;
        DBG2 ( "Timer %p stopped at time %ld (ran for %ld)\n",
               timer, now, runtime );

        /* Update timer.  Variables are:
         *
         *   r = round-trip time estimate (i.e. runtime)
         *   t = timeout value (i.e. timer->timeout)
         *   s = smoothed round-trip time
         *
         * By choice, we set t = 4s, i.e. allow for four times the
         * normal round-trip time to pass before retransmitting.
         *
         * We want to smooth according to s := ( 7 s + r ) / 8
         *
         * Since we don't actually store s, this reduces to
         * t := ( 7 t / 8 ) + ( r / 2 )
         *
         */
        if ( timer->count ) {
                timer->count--;
        } else {
                timer->timeout -= ( timer->timeout >> 3 );
                timer->timeout += ( runtime >> 1 );
                if ( timer->timeout != old_timeout ) {
                        DBG ( "Timer %p timeout updated to %ld\n",
                              timer, timer->timeout );
                }
        }
}

static void start_timer_nodelay

(

struct retry_timer *

timer

)

[inline, static]

Start timer with no delay.

Parameters:

timer

Retry timer

This starts the timer running with a zero timeout value.

Definition at line 66 of file retry.h.

References start_timer_fixed().

Referenced by dhcp_set_state(), ib_create_madx(), tcp_open(), tftp_core_open(), tftp_send_packet(), and tftp_timer_expired().

                                                                     {
        start_timer_fixed ( timer, 0 );
}

static __attribute__

(

(always_inline)

)

[inline, static]

Test to see if timer is currently running.

Parameters:

timer

Retry timer

Return values:

running

Non-zero if timer is running

Definition at line 76 of file retry.h.

                                            {
        return ( timer->running );
}