lwip/src/core/timeouts.c
2018-10-22 20:53:58 +02:00

452 lines
13 KiB
C

/**
* @file
* Stack-internal timers implementation.
* This file includes timer callbacks for stack-internal timers as well as
* functions to set up or stop timers and check for expired timers.
*
*/
/*
* Copyright (c) 2001-2004 Swedish Institute of Computer Science.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
* OF SUCH DAMAGE.
*
* This file is part of the lwIP TCP/IP stack.
*
* Author: Adam Dunkels <adam@sics.se>
* Simon Goldschmidt
*
*/
#include "lwip/opt.h"
#include "lwip/timeouts.h"
#include "lwip/priv/tcp_priv.h"
#include "lwip/def.h"
#include "lwip/memp.h"
#include "lwip/priv/tcpip_priv.h"
#include "lwip/ip4_frag.h"
#include "lwip/etharp.h"
#include "lwip/dhcp.h"
#include "lwip/acd.h"
#include "lwip/igmp.h"
#include "lwip/dns.h"
#include "lwip/nd6.h"
#include "lwip/ip6_frag.h"
#include "lwip/mld6.h"
#include "lwip/dhcp6.h"
#include "lwip/sys.h"
#include "lwip/pbuf.h"
#if LWIP_DEBUG_TIMERNAMES
#define HANDLER(x) x, #x
#else /* LWIP_DEBUG_TIMERNAMES */
#define HANDLER(x) x
#endif /* LWIP_DEBUG_TIMERNAMES */
#define LWIP_MAX_TIMEOUT 0x7fffffff
/* Check if timer's expiry time is greater than time and care about u32_t wraparounds */
#define TIME_LESS_THAN(t, compare_to) ( (((u32_t)((t)-(compare_to))) > LWIP_MAX_TIMEOUT) ? 1 : 0 )
/** This array contains all stack-internal cyclic timers. To get the number of
* timers, use LWIP_ARRAYSIZE() */
const struct lwip_cyclic_timer lwip_cyclic_timers[] = {
#if LWIP_TCP
/* The TCP timer is a special case: it does not have to run always and
is triggered to start from TCP using tcp_timer_needed() */
{TCP_TMR_INTERVAL, HANDLER(tcp_tmr)},
#endif /* LWIP_TCP */
#if LWIP_IPV4
#if IP_REASSEMBLY
{IP_TMR_INTERVAL, HANDLER(ip_reass_tmr)},
#endif /* IP_REASSEMBLY */
#if LWIP_ARP
{ARP_TMR_INTERVAL, HANDLER(etharp_tmr)},
#endif /* LWIP_ARP */
#if LWIP_DHCP
{DHCP_COARSE_TIMER_MSECS, HANDLER(dhcp_coarse_tmr)},
{DHCP_FINE_TIMER_MSECS, HANDLER(dhcp_fine_tmr)},
#endif /* LWIP_DHCP */
#if LWIP_ACD
{ACD_TMR_INTERVAL, HANDLER(acd_tmr)},
#endif /* LWIP_ACD */
#if LWIP_IGMP
{IGMP_TMR_INTERVAL, HANDLER(igmp_tmr)},
#endif /* LWIP_IGMP */
#endif /* LWIP_IPV4 */
#if LWIP_DNS
{DNS_TMR_INTERVAL, HANDLER(dns_tmr)},
#endif /* LWIP_DNS */
#if LWIP_IPV6
{ND6_TMR_INTERVAL, HANDLER(nd6_tmr)},
#if LWIP_IPV6_REASS
{IP6_REASS_TMR_INTERVAL, HANDLER(ip6_reass_tmr)},
#endif /* LWIP_IPV6_REASS */
#if LWIP_IPV6_MLD
{MLD6_TMR_INTERVAL, HANDLER(mld6_tmr)},
#endif /* LWIP_IPV6_MLD */
#if LWIP_IPV6_DHCP6
{DHCP6_TIMER_MSECS, HANDLER(dhcp6_tmr)},
#endif /* LWIP_IPV6_DHCP6 */
#endif /* LWIP_IPV6 */
};
const int lwip_num_cyclic_timers = LWIP_ARRAYSIZE(lwip_cyclic_timers);
#if LWIP_TIMERS && !LWIP_TIMERS_CUSTOM
/** The one and only timeout list */
static struct sys_timeo *next_timeout;
static u32_t current_timeout_due_time;
#if LWIP_TESTMODE
struct sys_timeo**
sys_timeouts_get_next_timeout(void)
{
return &next_timeout;
}
#endif
#if LWIP_TCP
/** global variable that shows if the tcp timer is currently scheduled or not */
static int tcpip_tcp_timer_active;
/**
* Timer callback function that calls tcp_tmr() and reschedules itself.
*
* @param arg unused argument
*/
static void
tcpip_tcp_timer(void *arg)
{
LWIP_UNUSED_ARG(arg);
/* call TCP timer handler */
tcp_tmr();
/* timer still needed? */
if (tcp_active_pcbs || tcp_tw_pcbs) {
/* restart timer */
sys_timeout(TCP_TMR_INTERVAL, tcpip_tcp_timer, NULL);
} else {
/* disable timer */
tcpip_tcp_timer_active = 0;
}
}
/**
* Called from TCP_REG when registering a new PCB:
* the reason is to have the TCP timer only running when
* there are active (or time-wait) PCBs.
*/
void
tcp_timer_needed(void)
{
LWIP_ASSERT_CORE_LOCKED();
/* timer is off but needed again? */
if (!tcpip_tcp_timer_active && (tcp_active_pcbs || tcp_tw_pcbs)) {
/* enable and start timer */
tcpip_tcp_timer_active = 1;
sys_timeout(TCP_TMR_INTERVAL, tcpip_tcp_timer, NULL);
}
}
#endif /* LWIP_TCP */
static void
#if LWIP_DEBUG_TIMERNAMES
sys_timeout_abs(u32_t abs_time, sys_timeout_handler handler, void *arg, const char *handler_name)
#else /* LWIP_DEBUG_TIMERNAMES */
sys_timeout_abs(u32_t abs_time, sys_timeout_handler handler, void *arg)
#endif
{
struct sys_timeo *timeout, *t;
timeout = (struct sys_timeo *)memp_malloc(MEMP_SYS_TIMEOUT);
if (timeout == NULL) {
LWIP_ASSERT("sys_timeout: timeout != NULL, pool MEMP_SYS_TIMEOUT is empty", timeout != NULL);
return;
}
timeout->next = NULL;
timeout->h = handler;
timeout->arg = arg;
timeout->time = abs_time;
#if LWIP_DEBUG_TIMERNAMES
timeout->handler_name = handler_name;
LWIP_DEBUGF(TIMERS_DEBUG, ("sys_timeout: %p abs_time=%"U32_F" handler=%s arg=%p\n",
(void *)timeout, abs_time, handler_name, (void *)arg));
#endif /* LWIP_DEBUG_TIMERNAMES */
if (next_timeout == NULL) {
next_timeout = timeout;
return;
}
if (TIME_LESS_THAN(timeout->time, next_timeout->time)) {
timeout->next = next_timeout;
next_timeout = timeout;
} else {
for (t = next_timeout; t != NULL; t = t->next) {
if ((t->next == NULL) || TIME_LESS_THAN(timeout->time, t->next->time)) {
timeout->next = t->next;
t->next = timeout;
break;
}
}
}
}
/**
* Timer callback function that calls cyclic->handler() and reschedules itself.
*
* @param arg unused argument
*/
#if !LWIP_TESTMODE
static
#endif
void
lwip_cyclic_timer(void *arg)
{
u32_t now;
u32_t next_timeout_time;
const struct lwip_cyclic_timer *cyclic = (const struct lwip_cyclic_timer *)arg;
#if LWIP_DEBUG_TIMERNAMES
LWIP_DEBUGF(TIMERS_DEBUG, ("tcpip: %s()\n", cyclic->handler_name));
#endif
cyclic->handler();
now = sys_now();
next_timeout_time = (u32_t)(current_timeout_due_time + cyclic->interval_ms); /* overflow handled by TIME_LESS_THAN macro */
if (TIME_LESS_THAN(next_timeout_time, now)) {
/* timer would immediately expire again -> "overload" -> restart without any correction */
#if LWIP_DEBUG_TIMERNAMES
sys_timeout_abs((u32_t)(now + cyclic->interval_ms), lwip_cyclic_timer, arg, cyclic->handler_name);
#else
sys_timeout_abs((u32_t)(now + cyclic->interval_ms), lwip_cyclic_timer, arg);
#endif
} else {
/* correct cyclic interval with handler execution delay and sys_check_timeouts jitter */
#if LWIP_DEBUG_TIMERNAMES
sys_timeout_abs(next_timeout_time, lwip_cyclic_timer, arg, cyclic->handler_name);
#else
sys_timeout_abs(next_timeout_time, lwip_cyclic_timer, arg);
#endif
}
}
/** Initialize this module */
void sys_timeouts_init(void)
{
size_t i;
/* tcp_tmr() at index 0 is started on demand */
for (i = (LWIP_TCP ? 1 : 0); i < LWIP_ARRAYSIZE(lwip_cyclic_timers); i++) {
/* we have to cast via size_t to get rid of const warning
(this is OK as cyclic_timer() casts back to const* */
sys_timeout(lwip_cyclic_timers[i].interval_ms, lwip_cyclic_timer, LWIP_CONST_CAST(void *, &lwip_cyclic_timers[i]));
}
}
/**
* Create a one-shot timer (aka timeout). Timeouts are processed in the
* following cases:
* - while waiting for a message using sys_timeouts_mbox_fetch()
* - by calling sys_check_timeouts() (NO_SYS==1 only)
*
* @param msecs time in milliseconds after that the timer should expire
* @param handler callback function to call when msecs have elapsed
* @param arg argument to pass to the callback function
*/
#if LWIP_DEBUG_TIMERNAMES
void
sys_timeout_debug(u32_t msecs, sys_timeout_handler handler, void *arg, const char *handler_name)
#else /* LWIP_DEBUG_TIMERNAMES */
void
sys_timeout(u32_t msecs, sys_timeout_handler handler, void *arg)
#endif /* LWIP_DEBUG_TIMERNAMES */
{
u32_t next_timeout_time;
LWIP_ASSERT_CORE_LOCKED();
LWIP_ASSERT("Timeout time too long, max is LWIP_UINT32_MAX/4 msecs", msecs <= (LWIP_UINT32_MAX / 4));
next_timeout_time = (u32_t)(sys_now() + msecs); /* overflow handled by TIME_LESS_THAN macro */
#if LWIP_DEBUG_TIMERNAMES
sys_timeout_abs(next_timeout_time, handler, arg, handler_name);
#else
sys_timeout_abs(next_timeout_time, handler, arg);
#endif
}
/**
* Go through timeout list (for this task only) and remove the first matching
* entry (subsequent entries remain untouched), even though the timeout has not
* triggered yet.
*
* @param handler callback function that would be called by the timeout
* @param arg callback argument that would be passed to handler
*/
void
sys_untimeout(sys_timeout_handler handler, void *arg)
{
struct sys_timeo *prev_t, *t;
LWIP_ASSERT_CORE_LOCKED();
if (next_timeout == NULL) {
return;
}
for (t = next_timeout, prev_t = NULL; t != NULL; prev_t = t, t = t->next) {
if ((t->h == handler) && (t->arg == arg)) {
/* We have a match */
/* Unlink from previous in list */
if (prev_t == NULL) {
next_timeout = t->next;
} else {
prev_t->next = t->next;
}
memp_free(MEMP_SYS_TIMEOUT, t);
return;
}
}
return;
}
/**
* @ingroup lwip_nosys
* Handle timeouts for NO_SYS==1 (i.e. without using
* tcpip_thread/sys_timeouts_mbox_fetch(). Uses sys_now() to call timeout
* handler functions when timeouts expire.
*
* Must be called periodically from your main loop.
*/
void
sys_check_timeouts(void)
{
u32_t now;
LWIP_ASSERT_CORE_LOCKED();
/* Process only timers expired at the start of the function. */
now = sys_now();
do {
struct sys_timeo *tmptimeout;
sys_timeout_handler handler;
void *arg;
PBUF_CHECK_FREE_OOSEQ();
tmptimeout = next_timeout;
if (tmptimeout == NULL) {
return;
}
if (TIME_LESS_THAN(now, tmptimeout->time)) {
return;
}
/* Timeout has expired */
next_timeout = tmptimeout->next;
handler = tmptimeout->h;
arg = tmptimeout->arg;
current_timeout_due_time = tmptimeout->time;
#if LWIP_DEBUG_TIMERNAMES
if (handler != NULL) {
LWIP_DEBUGF(TIMERS_DEBUG, ("sct calling h=%s t=%"U32_F" arg=%p\n",
tmptimeout->handler_name, sys_now() - tmptimeout->time, arg));
}
#endif /* LWIP_DEBUG_TIMERNAMES */
memp_free(MEMP_SYS_TIMEOUT, tmptimeout);
if (handler != NULL) {
handler(arg);
}
LWIP_TCPIP_THREAD_ALIVE();
/* Repeat until all expired timers have been called */
} while (1);
}
/** Rebase the timeout times to the current time.
* This is necessary if sys_check_timeouts() hasn't been called for a long
* time (e.g. while saving energy) to prevent all timer functions of that
* period being called.
*/
void
sys_restart_timeouts(void)
{
u32_t now;
u32_t base;
struct sys_timeo *t;
if (next_timeout == NULL) {
return;
}
now = sys_now();
base = next_timeout->time;
for (t = next_timeout; t != NULL; t = t->next) {
t->time = (t->time - base) + now;
}
}
/** Return the time left before the next timeout is due. If no timeouts are
* enqueued, returns 0xffffffff
*/
u32_t
sys_timeouts_sleeptime(void)
{
u32_t now;
LWIP_ASSERT_CORE_LOCKED();
if (next_timeout == NULL) {
return SYS_TIMEOUTS_SLEEPTIME_INFINITE;
}
now = sys_now();
if (TIME_LESS_THAN(next_timeout->time, now)) {
return 0;
} else {
u32_t ret = (u32_t)(next_timeout->time - now);
LWIP_ASSERT("invalid sleeptime", ret <= LWIP_MAX_TIMEOUT);
return ret;
}
}
#else /* LWIP_TIMERS && !LWIP_TIMERS_CUSTOM */
/* Satisfy the TCP code which calls this function */
void
tcp_timer_needed(void)
{
}
#endif /* LWIP_TIMERS && !LWIP_TIMERS_CUSTOM */