timers.c

00001 /**
00002  * @file
00003  * Stack-internal timers implementation.
00004  * This file includes timer callbacks for stack-internal timers as well as
00005  * functions to set up or stop timers and check for expired timers.
00006  *
00007  */
00008 
00009 /*
00010  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
00011  * All rights reserved.
00012  *
00013  * Redistribution and use in source and binary forms, with or without modification,
00014  * are permitted provided that the following conditions are met:
00015  *
00016  * 1. Redistributions of source code must retain the above copyright notice,
00017  *    this list of conditions and the following disclaimer.
00018  * 2. Redistributions in binary form must reproduce the above copyright notice,
00019  *    this list of conditions and the following disclaimer in the documentation
00020  *    and/or other materials provided with the distribution.
00021  * 3. The name of the author may not be used to endorse or promote products
00022  *    derived from this software without specific prior written permission.
00023  *
00024  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
00025  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
00026  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
00027  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
00028  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
00029  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
00030  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
00031  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
00032  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
00033  * OF SUCH DAMAGE.
00034  *
00035  * This file is part of the lwIP TCP/IP stack.
00036  *
00037  * Author: Adam Dunkels <adam@sics.se>
00038  *         Simon Goldschmidt
00039  *
00040  */
00041 
00042 #include "lwip/opt.h"
00043 
00044 #include "lwip/timers.h"
00045 
00046 #if LWIP_TIMERS
00047 
00048 #include "lwip/def.h"
00049 #include "lwip/memp.h"
00050 #include "lwip/tcpip.h"
00051 
00052 #include "lwip/tcp_impl.h"
00053 #include "lwip/ip_frag.h"
00054 #include "netif/etharp.h"
00055 #include "lwip/dhcp.h "
00056 #include "lwip/autoip.h"
00057 #include "lwip/igmp.h"
00058 #include "lwip/dns.h"
00059 
00060 
00061 /** The one and only timeout list */
00062 static struct sys_timeo *next_timeout;
00063 #if NO_SYS
00064 static u32_t timeouts_last_time;
00065 #endif /* NO_SYS */
00066 
00067 #if LWIP_TCP
00068 /** global variable that shows if the tcp timer is currently scheduled or not */
00069 static int tcpip_tcp_timer_active;
00070 
00071 /**
00072  * Timer callback function that calls tcp_tmr() and reschedules itself.
00073  *
00074  * @param arg unused argument
00075  */
00076 static void
00077 tcpip_tcp_timer(void *arg)
00078 {
00079   LWIP_UNUSED_ARG(arg);
00080 
00081   /* call TCP timer handler */
00082   tcp_tmr();
00083   /* timer still needed? */
00084   if (tcp_active_pcbs || tcp_tw_pcbs) {
00085     /* restart timer */
00086     sys_timeout(TCP_TMR_INTERVAL, tcpip_tcp_timer, NULL);
00087   } else {
00088     /* disable timer */
00089     tcpip_tcp_timer_active = 0;
00090   }
00091 }
00092 
00093 /**
00094  * Called from TCP_REG when registering a new PCB:
00095  * the reason is to have the TCP timer only running when
00096  * there are active (or time-wait) PCBs.
00097  */
00098 void
00099 tcp_timer_needed(void)
00100 {
00101   /* timer is off but needed again? */
00102   if (!tcpip_tcp_timer_active && (tcp_active_pcbs || tcp_tw_pcbs)) {
00103     /* enable and start timer */
00104     tcpip_tcp_timer_active = 1;
00105     sys_timeout(TCP_TMR_INTERVAL, tcpip_tcp_timer, NULL);
00106   }
00107 }
00108 #endif /* LWIP_TCP */
00109 
00110 #if IP_REASSEMBLY
00111 /**
00112  * Timer callback function that calls ip_reass_tmr() and reschedules itself.
00113  *
00114  * @param arg unused argument
00115  */
00116 static void
00117 ip_reass_timer(void *arg)
00118 {
00119   LWIP_UNUSED_ARG(arg);
00120   LWIP_DEBUGF(TIMERS_DEBUG, ("tcpip: ip_reass_tmr()\n"));
00121   ip_reass_tmr();
00122   sys_timeout(IP_TMR_INTERVAL, ip_reass_timer, NULL);
00123 }
00124 #endif /* IP_REASSEMBLY */
00125 
00126 #if LWIP_ARP
00127 /**
00128  * Timer callback function that calls etharp_tmr() and reschedules itself.
00129  *
00130  * @param arg unused argument
00131  */
00132 static void
00133 arp_timer(void *arg)
00134 {
00135   LWIP_UNUSED_ARG(arg);
00136   LWIP_DEBUGF(TIMERS_DEBUG, ("tcpip: etharp_tmr()\n"));
00137   etharp_tmr();
00138   sys_timeout(ARP_TMR_INTERVAL, arp_timer, NULL);
00139 }
00140 #endif /* LWIP_ARP */
00141 
00142 #if LWIP_DHCP
00143 /**
00144  * Timer callback function that calls dhcp_coarse_tmr() and reschedules itself.
00145  *
00146  * @param arg unused argument
00147  */
00148 static void
00149 dhcp_timer_coarse(void *arg)
00150 {
00151   LWIP_UNUSED_ARG(arg);
00152   LWIP_DEBUGF(TIMERS_DEBUG, ("tcpip: dhcp_coarse_tmr()\n"));
00153   dhcp_coarse_tmr();
00154   sys_timeout(DHCP_COARSE_TIMER_MSECS, dhcp_timer_coarse, NULL);
00155 }
00156 
00157 /**
00158  * Timer callback function that calls dhcp_fine_tmr() and reschedules itself.
00159  *
00160  * @param arg unused argument
00161  */
00162 static void
00163 dhcp_timer_fine(void *arg)
00164 {
00165   LWIP_UNUSED_ARG(arg);
00166   LWIP_DEBUGF(TIMERS_DEBUG, ("tcpip: dhcp_fine_tmr()\n"));
00167   dhcp_fine_tmr();
00168   sys_timeout(DHCP_FINE_TIMER_MSECS, dhcp_timer_fine, NULL);
00169 }
00170 #endif /* LWIP_DHCP */
00171 
00172 #if LWIP_AUTOIP
00173 /**
00174  * Timer callback function that calls autoip_tmr() and reschedules itself.
00175  *
00176  * @param arg unused argument
00177  */
00178 static void
00179 autoip_timer(void *arg)
00180 {
00181   LWIP_UNUSED_ARG(arg);
00182   LWIP_DEBUGF(TIMERS_DEBUG, ("tcpip: autoip_tmr()\n"));
00183   autoip_tmr();
00184   sys_timeout(AUTOIP_TMR_INTERVAL, autoip_timer, NULL);
00185 }
00186 #endif /* LWIP_AUTOIP */
00187 
00188 #if LWIP_IGMP
00189 /**
00190  * Timer callback function that calls igmp_tmr() and reschedules itself.
00191  *
00192  * @param arg unused argument
00193  */
00194 static void
00195 igmp_timer(void *arg)
00196 {
00197   LWIP_UNUSED_ARG(arg);
00198   LWIP_DEBUGF(TIMERS_DEBUG, ("tcpip: igmp_tmr()\n"));
00199   igmp_tmr();
00200   sys_timeout(IGMP_TMR_INTERVAL, igmp_timer, NULL);
00201 }
00202 #endif /* LWIP_IGMP */
00203 
00204 #if LWIP_DNS
00205 /**
00206  * Timer callback function that calls dns_tmr() and reschedules itself.
00207  *
00208  * @param arg unused argument
00209  */
00210 static void
00211 dns_timer(void *arg)
00212 {
00213   LWIP_UNUSED_ARG(arg);
00214   LWIP_DEBUGF(TIMERS_DEBUG, ("tcpip: dns_tmr()\n"));
00215   dns_tmr();
00216   sys_timeout(DNS_TMR_INTERVAL, dns_timer, NULL);
00217 }
00218 #endif /* LWIP_DNS */
00219 
00220 /** Initialize this module */
00221 void sys_timeouts_init(void)
00222 {
00223   next_timeout = NULL;
00224 #if IP_REASSEMBLY
00225   sys_timeout(IP_TMR_INTERVAL, ip_reass_timer, NULL);
00226 #endif /* IP_REASSEMBLY */
00227 #if LWIP_ARP
00228   sys_timeout(ARP_TMR_INTERVAL, arp_timer, NULL);
00229 #endif /* LWIP_ARP */
00230 #if LWIP_DHCP
00231   sys_timeout(DHCP_COARSE_TIMER_MSECS, dhcp_timer_coarse, NULL);
00232   sys_timeout(DHCP_FINE_TIMER_MSECS, dhcp_timer_fine, NULL);
00233 #endif /* LWIP_DHCP */
00234 #if LWIP_AUTOIP
00235   sys_timeout(AUTOIP_TMR_INTERVAL, autoip_timer, NULL);
00236 #endif /* LWIP_AUTOIP */
00237 #if LWIP_IGMP
00238   sys_timeout(IGMP_TMR_INTERVAL, igmp_timer, NULL);
00239 #endif /* LWIP_IGMP */
00240 #if LWIP_DNS
00241   sys_timeout(DNS_TMR_INTERVAL, dns_timer, NULL);
00242 #endif /* LWIP_DNS */
00243 
00244 #if NO_SYS
00245   /* Initialise timestamp for sys_check_timeouts */
00246   timeouts_last_time = sys_now();
00247 #endif
00248 }
00249 
00250 /**
00251  * Create a one-shot timer (aka timeout). Timeouts are processed in the
00252  * following cases:
00253  * - while waiting for a message using sys_timeouts_mbox_fetch()
00254  * - by calling sys_check_timeouts() (NO_SYS==1 only)
00255  *
00256  * @param msecs time in milliseconds after that the timer should expire
00257  * @param handler callback function to call when msecs have elapsed
00258  * @param arg argument to pass to the callback function
00259  */
00260 #if LWIP_DEBUG_TIMERNAMES
00261 void
00262 sys_timeout_debug(u32_t msecs, sys_timeout_handler handler, void *arg, const char* handler_name)
00263 #else /* LWIP_DEBUG_TIMERNAMES */
00264 void
00265 sys_timeout(u32_t msecs, sys_timeout_handler handler, void *arg)
00266 #endif /* LWIP_DEBUG_TIMERNAMES */
00267 {
00268   struct sys_timeo *timeout, *t;
00269 
00270   timeout = (struct sys_timeo *)memp_malloc(MEMP_SYS_TIMEOUT);
00271   if (timeout == NULL) {
00272     LWIP_ASSERT("sys_timeout: timeout != NULL, pool MEMP_SYS_TIMEOUT is empty", timeout != NULL);
00273     return;
00274   }
00275   timeout->next = NULL;
00276   timeout->h = handler;
00277   timeout->arg = arg;
00278   timeout->time = msecs;
00279 #if LWIP_DEBUG_TIMERNAMES
00280   timeout->handler_name = handler_name;
00281   LWIP_DEBUGF(TIMERS_DEBUG, ("sys_timeout: %p msecs=%"U32_F" handler=%s arg=%p\n",
00282     (void *)timeout, msecs, handler_name, (void *)arg));
00283 #endif /* LWIP_DEBUG_TIMERNAMES */
00284 
00285   if (next_timeout == NULL) {
00286     next_timeout = timeout;
00287     return;
00288   }
00289 
00290   if (next_timeout->time > msecs) {
00291     next_timeout->time -= msecs;
00292     timeout->next = next_timeout;
00293     next_timeout = timeout;
00294   } else {
00295     for(t = next_timeout; t != NULL; t = t->next) {
00296       timeout->time -= t->time;
00297       if (t->next == NULL || t->next->time > timeout->time) {
00298         if (t->next != NULL) {
00299           t->next->time -= timeout->time;
00300         }
00301         timeout->next = t->next;
00302         t->next = timeout;
00303         break;
00304       }
00305     }
00306   }
00307 }
00308 
00309 /**
00310  * Go through timeout list (for this task only) and remove the first matching
00311  * entry, even though the timeout has not triggered yet.
00312  *
00313  * @note This function only works as expected if there is only one timeout
00314  * calling 'handler' in the list of timeouts.
00315  *
00316  * @param handler callback function that would be called by the timeout
00317  * @param arg callback argument that would be passed to handler
00318 */
00319 void
00320 sys_untimeout(sys_timeout_handler handler, void *arg)
00321 {
00322   struct sys_timeo *prev_t, *t;
00323 
00324   if (next_timeout == NULL) {
00325     return;
00326   }
00327 
00328   for (t = next_timeout, prev_t = NULL; t != NULL; prev_t = t, t = t->next) {
00329     if ((t->h == handler) && (t->arg == arg)) {
00330       /* We have a match */
00331       /* Unlink from previous in list */
00332       if (prev_t == NULL) {
00333         next_timeout = t->next;
00334       } else {
00335         prev_t->next = t->next;
00336       }
00337       /* If not the last one, add time of this one back to next */
00338       if (t->next != NULL) {
00339         t->next->time += t->time;
00340       }
00341       memp_free(MEMP_SYS_TIMEOUT, t);
00342       return;
00343     }
00344   }
00345   return;
00346 }
00347 
00348 #if NO_SYS
00349 
00350 /** Handle timeouts for NO_SYS==1 (i.e. without using
00351  * tcpip_thread/sys_timeouts_mbox_fetch(). Uses sys_now() to call timeout
00352  * handler functions when timeouts expire.
00353  *
00354  * Must be called periodically from your main loop.
00355  */
00356 void
00357 sys_check_timeouts(void)
00358 {
00359   struct sys_timeo *tmptimeout;
00360   u32_t diff;
00361   sys_timeout_handler handler;
00362   void *arg;
00363   int had_one;
00364   u32_t now;
00365 
00366   now = sys_now();
00367   if (next_timeout) {
00368     /* this cares for wraparounds */
00369     diff = LWIP_U32_DIFF(now, timeouts_last_time);
00370     do
00371     {
00372       had_one = 0;
00373       tmptimeout = next_timeout;
00374       if (tmptimeout->time <= diff) {
00375         /* timeout has expired */
00376         had_one = 1;
00377         timeouts_last_time = now;
00378         diff -= tmptimeout->time;
00379         next_timeout = tmptimeout->next;
00380         handler = tmptimeout->h;
00381         arg = tmptimeout->arg;
00382 #if LWIP_DEBUG_TIMERNAMES
00383         if (handler != NULL) {
00384           LWIP_DEBUGF(TIMERS_DEBUG, ("sct calling h=%s arg=%p\n",
00385             tmptimeout->handler_name, arg));
00386         }
00387 #endif /* LWIP_DEBUG_TIMERNAMES */
00388         memp_free(MEMP_SYS_TIMEOUT, tmptimeout);
00389         if (handler != NULL) {
00390           handler(arg);
00391         }
00392       }
00393     /* repeat until all expired timers have been called */
00394     }while(had_one);
00395   }
00396 }
00397 
00398 /** Set back the timestamp of the last call to sys_check_timeouts()
00399  * This is necessary if sys_check_timeouts() hasn't been called for a long
00400  * time (e.g. while saving energy) to prevent all timer functions of that
00401  * period being called.
00402  */
00403 void
00404 sys_restart_timeouts(void)
00405 {
00406   timeouts_last_time = sys_now();
00407 }
00408 
00409 #else /* NO_SYS */
00410 
00411 /**
00412  * Wait (forever) for a message to arrive in an mbox.
00413  * While waiting, timeouts are processed.
00414  *
00415  * @param mbox the mbox to fetch the message from
00416  * @param msg the place to store the message
00417  */
00418 void
00419 sys_timeouts_mbox_fetch(sys_mbox_t *mbox, void **msg)
00420 {
00421   u32_t time_needed;
00422   struct sys_timeo *tmptimeout;
00423   sys_timeout_handler handler;
00424   void *arg;
00425 
00426  again:
00427   if (!next_timeout) {
00428     time_needed = sys_arch_mbox_fetch(mbox, msg, 0);
00429   } else {
00430     if (next_timeout->time > 0) {
00431       time_needed = sys_arch_mbox_fetch(mbox, msg, next_timeout->time);
00432     } else {
00433       time_needed = SYS_ARCH_TIMEOUT;
00434     }
00435 
00436     if (time_needed == SYS_ARCH_TIMEOUT) {
00437       /* If time == SYS_ARCH_TIMEOUT, a timeout occured before a message
00438          could be fetched. We should now call the timeout handler and
00439          deallocate the memory allocated for the timeout. */
00440       tmptimeout = next_timeout;
00441       next_timeout = tmptimeout->next;
00442       handler = tmptimeout->h;
00443       arg = tmptimeout->arg;
00444 #if LWIP_DEBUG_TIMERNAMES
00445       if (handler != NULL) {
00446         LWIP_DEBUGF(TIMERS_DEBUG, ("stmf calling h=%s arg=%p\n",
00447           tmptimeout->handler_name, arg));
00448       }
00449 #endif /* LWIP_DEBUG_TIMERNAMES */
00450       memp_free(MEMP_SYS_TIMEOUT, tmptimeout);
00451       if (handler != NULL) {
00452         /* For LWIP_TCPIP_CORE_LOCKING, lock the core before calling the
00453            timeout handler function. */
00454         LOCK_TCPIP_CORE();
00455         handler(arg);
00456         UNLOCK_TCPIP_CORE();
00457       }
00458       LWIP_TCPIP_THREAD_ALIVE();
00459 
00460       /* We try again to fetch a message from the mbox. */
00461       goto again;
00462     } else {
00463       /* If time != SYS_ARCH_TIMEOUT, a message was received before the timeout
00464          occured. The time variable is set to the number of
00465          milliseconds we waited for the message. */
00466       if (time_needed < next_timeout->time) {
00467         next_timeout->time -= time_needed;
00468       } else {
00469         next_timeout->time = 0;
00470       }
00471     }
00472   }
00473 }
00474 
00475 #endif /* NO_SYS */
00476 
00477 #else /* LWIP_TIMERS */
00478 /* Satisfy the TCP code which calls this function */
00479 void
00480 tcp_timer_needed(void)
00481 {
00482 }
00483 #endif /* LWIP_TIMERS */