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 #include "lwip/tcp_impl.h"
00046 
00047 #if LWIP_TIMERS
00048 
00049 #include "lwip/def.h"
00050 #include "lwip/memp.h"
00051 #include "lwip/tcpip.h"
00052 
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 #if IP_REASSEMBLY
00224   sys_timeout(IP_TMR_INTERVAL, ip_reass_timer, NULL);
00225 #endif /* IP_REASSEMBLY */
00226 #if LWIP_ARP
00227   sys_timeout(ARP_TMR_INTERVAL, arp_timer, NULL);
00228 #endif /* LWIP_ARP */
00229 #if LWIP_DHCP
00230   sys_timeout(DHCP_COARSE_TIMER_MSECS, dhcp_timer_coarse, NULL);
00231   sys_timeout(DHCP_FINE_TIMER_MSECS, dhcp_timer_fine, NULL);
00232 #endif /* LWIP_DHCP */
00233 #if LWIP_AUTOIP
00234   sys_timeout(AUTOIP_TMR_INTERVAL, autoip_timer, NULL);
00235 #endif /* LWIP_AUTOIP */
00236 #if LWIP_IGMP
00237   sys_timeout(IGMP_TMR_INTERVAL, igmp_timer, NULL);
00238 #endif /* LWIP_IGMP */
00239 #if LWIP_DNS
00240   sys_timeout(DNS_TMR_INTERVAL, dns_timer, NULL);
00241 #endif /* LWIP_DNS */
00242 
00243 #if NO_SYS
00244   /* Initialise timestamp for sys_check_timeouts */
00245   timeouts_last_time = sys_now();
00246 #endif
00247 }
00248 
00249 /**
00250  * Create a one-shot timer (aka timeout). Timeouts are processed in the
00251  * following cases:
00252  * - while waiting for a message using sys_timeouts_mbox_fetch()
00253  * - by calling sys_check_timeouts() (NO_SYS==1 only)
00254  *
00255  * @param msecs time in milliseconds after that the timer should expire
00256  * @param handler callback function to call when msecs have elapsed
00257  * @param arg argument to pass to the callback function
00258  */
00259 #if LWIP_DEBUG_TIMERNAMES
00260 void
00261 sys_timeout_debug(u32_t msecs, sys_timeout_handler handler, void *arg, const char* handler_name)
00262 #else /* LWIP_DEBUG_TIMERNAMES */
00263 void
00264 sys_timeout(u32_t msecs, sys_timeout_handler handler, void *arg)
00265 #endif /* LWIP_DEBUG_TIMERNAMES */
00266 {
00267   struct sys_timeo *timeout, *t;
00268 
00269   timeout = (struct sys_timeo *)memp_malloc(MEMP_SYS_TIMEOUT);
00270   if (timeout == NULL) {
00271     LWIP_ASSERT("sys_timeout: timeout != NULL, pool MEMP_SYS_TIMEOUT is empty", timeout != NULL);
00272     return;
00273   }
00274   timeout->next = NULL;
00275   timeout->h = handler;
00276   timeout->arg = arg;
00277   timeout->time = msecs;
00278 #if LWIP_DEBUG_TIMERNAMES
00279   timeout->handler_name = handler_name;
00280   LWIP_DEBUGF(TIMERS_DEBUG, ("sys_timeout: %p msecs=%"U32_F" handler=%s arg=%p\n",
00281     (void *)timeout, msecs, handler_name, (void *)arg));
00282 #endif /* LWIP_DEBUG_TIMERNAMES */
00283 
00284   if (next_timeout == NULL) {
00285     next_timeout = timeout;
00286     return;
00287   }
00288 
00289   if (next_timeout->time > msecs) {
00290     next_timeout->time -= msecs;
00291     timeout->next = next_timeout;
00292     next_timeout = timeout;
00293   } else {
00294     for(t = next_timeout; t != NULL; t = t->next) {
00295       timeout->time -= t->time;
00296       if (t->next == NULL || t->next->time > timeout->time) {
00297         if (t->next != NULL) {
00298           t->next->time -= timeout->time;
00299         }
00300         timeout->next = t->next;
00301         t->next = timeout;
00302         break;
00303       }
00304     }
00305   }
00306 }
00307 
00308 /**
00309  * Go through timeout list (for this task only) and remove the first matching
00310  * entry, even though the timeout has not triggered yet.
00311  *
00312  * @note This function only works as expected if there is only one timeout
00313  * calling 'handler' in the list of timeouts.
00314  *
00315  * @param handler callback function that would be called by the timeout
00316  * @param arg callback argument that would be passed to handler
00317 */
00318 void
00319 sys_untimeout(sys_timeout_handler handler, void *arg)
00320 {
00321   struct sys_timeo *prev_t, *t;
00322 
00323   if (next_timeout == NULL) {
00324     return;
00325   }
00326 
00327   for (t = next_timeout, prev_t = NULL; t != NULL; prev_t = t, t = t->next) {
00328     if ((t->h == handler) && (t->arg == arg)) {
00329       /* We have a match */
00330       /* Unlink from previous in list */
00331       if (prev_t == NULL) {
00332         next_timeout = t->next;
00333       } else {
00334         prev_t->next = t->next;
00335       }
00336       /* If not the last one, add time of this one back to next */
00337       if (t->next != NULL) {
00338         t->next->time += t->time;
00339       }
00340       memp_free(MEMP_SYS_TIMEOUT, t);
00341       return;
00342     }
00343   }
00344   return;
00345 }
00346 
00347 #if NO_SYS
00348 
00349 /** Handle timeouts for NO_SYS==1 (i.e. without using
00350  * tcpip_thread/sys_timeouts_mbox_fetch(). Uses sys_now() to call timeout
00351  * handler functions when timeouts expire.
00352  *
00353  * Must be called periodically from your main loop.
00354  */
00355 void
00356 sys_check_timeouts(void)
00357 {
00358   struct sys_timeo *tmptimeout;
00359   u32_t diff;
00360   sys_timeout_handler handler;
00361   void *arg;
00362   int had_one;
00363   u32_t now;
00364 
00365   now = sys_now();
00366   if (next_timeout) {
00367     /* this cares for wraparounds */
00368     diff = LWIP_U32_DIFF(now, timeouts_last_time);
00369     do
00370     {
00371       had_one = 0;
00372       tmptimeout = next_timeout;
00373       if (tmptimeout->time <= diff) {
00374         /* timeout has expired */
00375         had_one = 1;
00376         timeouts_last_time = now;
00377         diff -= tmptimeout->time;
00378         next_timeout = tmptimeout->next;
00379         handler = tmptimeout->h;
00380         arg = tmptimeout->arg;
00381 #if LWIP_DEBUG_TIMERNAMES
00382         if (handler != NULL) {
00383           LWIP_DEBUGF(TIMERS_DEBUG, ("sct calling h=%s arg=%p\n",
00384             tmptimeout->handler_name, arg));
00385         }
00386 #endif /* LWIP_DEBUG_TIMERNAMES */
00387         memp_free(MEMP_SYS_TIMEOUT, tmptimeout);
00388         if (handler != NULL) {
00389           handler(arg);
00390         }
00391       }
00392     /* repeat until all expired timers have been called */
00393     }while(had_one);
00394   }
00395 }
00396 
00397 /** Set back the timestamp of the last call to sys_check_timeouts()
00398  * This is necessary if sys_check_timeouts() hasn't been called for a long
00399  * time (e.g. while saving energy) to prevent all timer functions of that
00400  * period being called.
00401  */
00402 void
00403 sys_restart_timeouts(void)
00404 {
00405   timeouts_last_time = sys_now();
00406 }
00407 
00408 #else /* NO_SYS */
00409 
00410 /**
00411  * Wait (forever) for a message to arrive in an mbox.
00412  * While waiting, timeouts are processed.
00413  *
00414  * @param mbox the mbox to fetch the message from
00415  * @param msg the place to store the message
00416  */
00417 void
00418 sys_timeouts_mbox_fetch(sys_mbox_t *mbox, void **msg)
00419 {
00420   u32_t time_needed;
00421   struct sys_timeo *tmptimeout;
00422   sys_timeout_handler handler;
00423   void *arg;
00424 
00425  again:
00426   if (!next_timeout) {
00427     time_needed = sys_arch_mbox_fetch(mbox, msg, 0);
00428   } else {
00429     if (next_timeout->time > 0) {
00430       time_needed = sys_arch_mbox_fetch(mbox, msg, next_timeout->time);
00431     } else {
00432       time_needed = SYS_ARCH_TIMEOUT;
00433     }
00434 
00435     if (time_needed == SYS_ARCH_TIMEOUT) {
00436       /* If time == SYS_ARCH_TIMEOUT, a timeout occured before a message
00437          could be fetched. We should now call the timeout handler and
00438          deallocate the memory allocated for the timeout. */
00439       tmptimeout = next_timeout;
00440       next_timeout = tmptimeout->next;
00441       handler = tmptimeout->h;
00442       arg = tmptimeout->arg;
00443 #if LWIP_DEBUG_TIMERNAMES
00444       if (handler != NULL) {
00445         LWIP_DEBUGF(TIMERS_DEBUG, ("stmf calling h=%s arg=%p\n",
00446           tmptimeout->handler_name, arg));
00447       }
00448 #endif /* LWIP_DEBUG_TIMERNAMES */
00449       memp_free(MEMP_SYS_TIMEOUT, tmptimeout);
00450       if (handler != NULL) {
00451         /* For LWIP_TCPIP_CORE_LOCKING, lock the core before calling the
00452            timeout handler function. */
00453         LOCK_TCPIP_CORE();
00454         handler(arg);
00455         UNLOCK_TCPIP_CORE();
00456       }
00457       LWIP_TCPIP_THREAD_ALIVE();
00458 
00459       /* We try again to fetch a message from the mbox. */
00460       goto again;
00461     } else {
00462       /* If time != SYS_ARCH_TIMEOUT, a message was received before the timeout
00463          occured. The time variable is set to the number of
00464          milliseconds we waited for the message. */
00465       if (time_needed < next_timeout->time) {
00466         next_timeout->time -= time_needed;
00467       } else {
00468         next_timeout->time = 0;
00469       }
00470     }
00471   }
00472 }
00473 
00474 #endif /* NO_SYS */
00475 
00476 #else /* LWIP_TIMERS */
00477 /* Satisfy the TCP code which calls this function */
00478 void
00479 tcp_timer_needed(void)
00480 {
00481 }
00482 #endif /* LWIP_TIMERS */