1 /** 2 * @file 3 * Stack-internal timers implementation. 4 * This file includes timer callbacks for stack-internal timers as well as 5 * functions to set up or stop timers and check for expired timers. 6 * 7 */ 8 9 /* 10 * Copyright (c) 2001-2004 Swedish Institute of Computer Science. 11 * All rights reserved. 12 * 13 * Redistribution and use in source and binary forms, with or without modification, 14 * are permitted provided that the following conditions are met: 15 * 16 * 1. Redistributions of source code must retain the above copyright notice, 17 * this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright notice, 19 * this list of conditions and the following disclaimer in the documentation 20 * and/or other materials provided with the distribution. 21 * 3. The name of the author may not be used to endorse or promote products 22 * derived from this software without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 25 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 26 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 27 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 28 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 29 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 30 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 31 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 32 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 33 * OF SUCH DAMAGE. 34 * 35 * This file is part of the lwIP TCP/IP stack. 36 * 37 * Author: Adam Dunkels <adam@sics.se> 38 * Simon Goldschmidt 39 * 40 */ 41 42 #include "lwip/opt.h" 43 44 #include "lwip/timeouts.h" 45 #include "lwip/priv/tcp_priv.h" 46 47 #include "lwip/def.h" 48 #include "lwip/memp.h" 49 #include "lwip/priv/tcpip_priv.h" 50 51 #include "lwip/ip4_frag.h" 52 #include "lwip/etharp.h" 53 #include "lwip/dhcp.h" 54 #include "lwip/autoip.h" 55 #include "lwip/igmp.h" 56 #include "lwip/dns.h" 57 #include "lwip/nd6.h" 58 #include "lwip/ip6_frag.h" 59 #include "lwip/mld6.h" 60 #include "lwip/sys.h" 61 #include "lwip/pbuf.h" 62 63 #if LWIP_DEBUG_TIMERNAMES 64 #define HANDLER(x) x, #x 65 #else /* LWIP_DEBUG_TIMERNAMES */ 66 #define HANDLER(x) x 67 #endif /* LWIP_DEBUG_TIMERNAMES */ 68 69 /** This array contains all stack-internal cyclic timers. To get the number of 70 * timers, use LWIP_ARRAYSIZE() */ 71 const struct lwip_cyclic_timer lwip_cyclic_timers[] = { 72 #if LWIP_TCP 73 /* The TCP timer is a special case: it does not have to run always and 74 is triggered to start from TCP using tcp_timer_needed() */ 75 {TCP_TMR_INTERVAL, HANDLER(tcp_tmr)}, 76 #endif /* LWIP_TCP */ 77 #if LWIP_IPV4 78 #if IP_REASSEMBLY 79 {IP_TMR_INTERVAL, HANDLER(ip_reass_tmr)}, 80 #endif /* IP_REASSEMBLY */ 81 #if LWIP_ARP 82 {ARP_TMR_INTERVAL, HANDLER(etharp_tmr)}, 83 #endif /* LWIP_ARP */ 84 #if LWIP_DHCP 85 {DHCP_COARSE_TIMER_MSECS, HANDLER(dhcp_coarse_tmr)}, 86 {DHCP_FINE_TIMER_MSECS, HANDLER(dhcp_fine_tmr)}, 87 #endif /* LWIP_DHCP */ 88 #if LWIP_AUTOIP 89 {AUTOIP_TMR_INTERVAL, HANDLER(autoip_tmr)}, 90 #endif /* LWIP_AUTOIP */ 91 #if LWIP_IGMP 92 {IGMP_TMR_INTERVAL, HANDLER(igmp_tmr)}, 93 #endif /* LWIP_IGMP */ 94 #endif /* LWIP_IPV4 */ 95 #if LWIP_DNS 96 {DNS_TMR_INTERVAL, HANDLER(dns_tmr)}, 97 #endif /* LWIP_DNS */ 98 #if LWIP_IPV6 99 {ND6_TMR_INTERVAL, HANDLER(nd6_tmr)}, 100 #if LWIP_IPV6_REASS 101 {IP6_REASS_TMR_INTERVAL, HANDLER(ip6_reass_tmr)}, 102 #endif /* LWIP_IPV6_REASS */ 103 #if LWIP_IPV6_MLD 104 {MLD6_TMR_INTERVAL, HANDLER(mld6_tmr)}, 105 #endif /* LWIP_IPV6_MLD */ 106 #endif /* LWIP_IPV6 */ 107 }; 108 109 #if LWIP_TIMERS && !LWIP_TIMERS_CUSTOM 110 111 /** The one and only timeout list */ 112 static struct sys_timeo *next_timeout; 113 static u32_t timeouts_last_time; 114 115 #if LWIP_TCP 116 /** global variable that shows if the tcp timer is currently scheduled or not */ 117 static int tcpip_tcp_timer_active; 118 119 /** 120 * Timer callback function that calls tcp_tmr() and reschedules itself. 121 * 122 * @param arg unused argument 123 */ 124 static void 125 tcpip_tcp_timer(void *arg) 126 { 127 LWIP_UNUSED_ARG(arg); 128 129 /* call TCP timer handler */ 130 tcp_tmr(); 131 /* timer still needed? */ 132 if (tcp_active_pcbs || tcp_tw_pcbs) { 133 /* restart timer */ 134 sys_timeout(TCP_TMR_INTERVAL, tcpip_tcp_timer, NULL); 135 } else { 136 /* disable timer */ 137 tcpip_tcp_timer_active = 0; 138 } 139 } 140 141 /** 142 * Called from TCP_REG when registering a new PCB: 143 * the reason is to have the TCP timer only running when 144 * there are active (or time-wait) PCBs. 145 */ 146 void 147 tcp_timer_needed(void) 148 { 149 /* timer is off but needed again? */ 150 if (!tcpip_tcp_timer_active && (tcp_active_pcbs || tcp_tw_pcbs)) { 151 /* enable and start timer */ 152 tcpip_tcp_timer_active = 1; 153 sys_timeout(TCP_TMR_INTERVAL, tcpip_tcp_timer, NULL); 154 } 155 } 156 #endif /* LWIP_TCP */ 157 158 /** 159 * Timer callback function that calls mld6_tmr() and reschedules itself. 160 * 161 * @param arg unused argument 162 */ 163 static void 164 cyclic_timer(void *arg) 165 { 166 const struct lwip_cyclic_timer* cyclic = (const struct lwip_cyclic_timer*)arg; 167 #if LWIP_DEBUG_TIMERNAMES 168 LWIP_DEBUGF(TIMERS_DEBUG, ("tcpip: %s()\n", cyclic->handler_name)); 169 #endif 170 cyclic->handler(); 171 sys_timeout(cyclic->interval_ms, cyclic_timer, arg); 172 } 173 174 /** Initialize this module */ 175 void sys_timeouts_init(void) 176 { 177 size_t i; 178 /* tcp_tmr() at index 0 is started on demand */ 179 for (i = 1; i < LWIP_ARRAYSIZE(lwip_cyclic_timers); i++) { 180 /* we have to cast via size_t to get rid of const warning 181 (this is OK as cyclic_timer() casts back to const* */ 182 sys_timeout(lwip_cyclic_timers[i].interval_ms, cyclic_timer, LWIP_CONST_CAST(void*, &lwip_cyclic_timers[i])); 183 } 184 185 /* Initialise timestamp for sys_check_timeouts */ 186 timeouts_last_time = sys_now(); 187 } 188 189 /** 190 * Create a one-shot timer (aka timeout). Timeouts are processed in the 191 * following cases: 192 * - while waiting for a message using sys_timeouts_mbox_fetch() 193 * - by calling sys_check_timeouts() (NO_SYS==1 only) 194 * 195 * @param msecs time in milliseconds after that the timer should expire 196 * @param handler callback function to call when msecs have elapsed 197 * @param arg argument to pass to the callback function 198 */ 199 #if LWIP_DEBUG_TIMERNAMES 200 void 201 sys_timeout_debug(u32_t msecs, sys_timeout_handler handler, void *arg, const char* handler_name) 202 #else /* LWIP_DEBUG_TIMERNAMES */ 203 void 204 sys_timeout(u32_t msecs, sys_timeout_handler handler, void *arg) 205 #endif /* LWIP_DEBUG_TIMERNAMES */ 206 { 207 struct sys_timeo *timeout, *t; 208 u32_t now, diff; 209 210 timeout = (struct sys_timeo *)memp_malloc(MEMP_SYS_TIMEOUT); 211 if (timeout == NULL) { 212 LWIP_ASSERT("sys_timeout: timeout != NULL, pool MEMP_SYS_TIMEOUT is empty", timeout != NULL); 213 return; 214 } 215 216 now = sys_now(); 217 if (next_timeout == NULL) { 218 diff = 0; 219 timeouts_last_time = now; 220 } else { 221 diff = now - timeouts_last_time; 222 } 223 224 timeout->next = NULL; 225 timeout->h = handler; 226 timeout->arg = arg; 227 timeout->time = msecs + diff; 228 #if LWIP_DEBUG_TIMERNAMES 229 timeout->handler_name = handler_name; 230 LWIP_DEBUGF(TIMERS_DEBUG, ("sys_timeout: %p msecs=%"U32_F" handler=%s arg=%p\n", 231 (void *)timeout, msecs, handler_name, (void *)arg)); 232 #endif /* LWIP_DEBUG_TIMERNAMES */ 233 234 if (next_timeout == NULL) { 235 next_timeout = timeout; 236 return; 237 } 238 239 if (next_timeout->time > msecs) { 240 next_timeout->time -= msecs; 241 timeout->next = next_timeout; 242 next_timeout = timeout; 243 } else { 244 for (t = next_timeout; t != NULL; t = t->next) { 245 timeout->time -= t->time; 246 if (t->next == NULL || t->next->time > timeout->time) { 247 if (t->next != NULL) { 248 t->next->time -= timeout->time; 249 } else if (timeout->time > msecs) { 250 /* If this is the case, 'timeouts_last_time' and 'now' differs too much. 251 This can be due to sys_check_timeouts() not being called at the right 252 times, but also when stopping in a breakpoint. Anyway, let's assume 253 this is not wanted, so add the first timer's time instead of 'diff' */ 254 timeout->time = msecs + next_timeout->time; 255 } 256 timeout->next = t->next; 257 t->next = timeout; 258 break; 259 } 260 } 261 } 262 } 263 264 /** 265 * Go through timeout list (for this task only) and remove the first matching 266 * entry (subsequent entries remain untouched), even though the timeout has not 267 * triggered yet. 268 * 269 * @param handler callback function that would be called by the timeout 270 * @param arg callback argument that would be passed to handler 271 */ 272 void 273 sys_untimeout(sys_timeout_handler handler, void *arg) 274 { 275 struct sys_timeo *prev_t, *t; 276 277 if (next_timeout == NULL) { 278 return; 279 } 280 281 for (t = next_timeout, prev_t = NULL; t != NULL; prev_t = t, t = t->next) { 282 if ((t->h == handler) && (t->arg == arg)) { 283 /* We have a match */ 284 /* Unlink from previous in list */ 285 if (prev_t == NULL) { 286 next_timeout = t->next; 287 } else { 288 prev_t->next = t->next; 289 } 290 /* If not the last one, add time of this one back to next */ 291 if (t->next != NULL) { 292 t->next->time += t->time; 293 } 294 memp_free(MEMP_SYS_TIMEOUT, t); 295 return; 296 } 297 } 298 return; 299 } 300 301 /** 302 * @ingroup lwip_nosys 303 * Handle timeouts for NO_SYS==1 (i.e. without using 304 * tcpip_thread/sys_timeouts_mbox_fetch(). Uses sys_now() to call timeout 305 * handler functions when timeouts expire. 306 * 307 * Must be called periodically from your main loop. 308 */ 309 #if !NO_SYS && !defined __DOXYGEN__ 310 static 311 #endif /* !NO_SYS */ 312 void 313 sys_check_timeouts(void) 314 { 315 if (next_timeout) { 316 struct sys_timeo *tmptimeout; 317 u32_t diff; 318 sys_timeout_handler handler; 319 void *arg; 320 u8_t had_one; 321 u32_t now; 322 323 now = sys_now(); 324 /* this cares for wraparounds */ 325 diff = now - timeouts_last_time; 326 do { 327 PBUF_CHECK_FREE_OOSEQ(); 328 had_one = 0; 329 tmptimeout = next_timeout; 330 if (tmptimeout && (tmptimeout->time <= diff)) { 331 /* timeout has expired */ 332 had_one = 1; 333 timeouts_last_time += tmptimeout->time; 334 diff -= tmptimeout->time; 335 next_timeout = tmptimeout->next; 336 handler = tmptimeout->h; 337 arg = tmptimeout->arg; 338 #if LWIP_DEBUG_TIMERNAMES 339 if (handler != NULL) { 340 LWIP_DEBUGF(TIMERS_DEBUG, ("sct calling h=%s arg=%p\n", 341 tmptimeout->handler_name, arg)); 342 } 343 #endif /* LWIP_DEBUG_TIMERNAMES */ 344 memp_free(MEMP_SYS_TIMEOUT, tmptimeout); 345 if (handler != NULL) { 346 #if !NO_SYS 347 /* For LWIP_TCPIP_CORE_LOCKING, lock the core before calling the 348 timeout handler function. */ 349 LOCK_TCPIP_CORE(); 350 #endif /* !NO_SYS */ 351 handler(arg); 352 #if !NO_SYS 353 UNLOCK_TCPIP_CORE(); 354 #endif /* !NO_SYS */ 355 } 356 LWIP_TCPIP_THREAD_ALIVE(); 357 } 358 /* repeat until all expired timers have been called */ 359 } while (had_one); 360 } 361 } 362 363 /** Set back the timestamp of the last call to sys_check_timeouts() 364 * This is necessary if sys_check_timeouts() hasn't been called for a long 365 * time (e.g. while saving energy) to prevent all timer functions of that 366 * period being called. 367 */ 368 void 369 sys_restart_timeouts(void) 370 { 371 timeouts_last_time = sys_now(); 372 } 373 374 /** Return the time left before the next timeout is due. If no timeouts are 375 * enqueued, returns 0xffffffff 376 */ 377 #if !NO_SYS 378 static 379 #endif /* !NO_SYS */ 380 u32_t 381 sys_timeouts_sleeptime(void) 382 { 383 u32_t diff; 384 if (next_timeout == NULL) { 385 return 0xffffffff; 386 } 387 diff = sys_now() - timeouts_last_time; 388 if (diff > next_timeout->time) { 389 return 0; 390 } else { 391 return next_timeout->time - diff; 392 } 393 } 394 395 #if !NO_SYS 396 397 /** 398 * Wait (forever) for a message to arrive in an mbox. 399 * While waiting, timeouts are processed. 400 * 401 * @param mbox the mbox to fetch the message from 402 * @param msg the place to store the message 403 */ 404 void 405 sys_timeouts_mbox_fetch(sys_mbox_t *mbox, void **msg) 406 { 407 u32_t sleeptime; 408 409 again: 410 if (!next_timeout) { 411 sys_arch_mbox_fetch(mbox, msg, 0); 412 return; 413 } 414 415 sleeptime = sys_timeouts_sleeptime(); 416 if (sleeptime == 0 || sys_arch_mbox_fetch(mbox, msg, sleeptime) == SYS_ARCH_TIMEOUT) { 417 /* If a SYS_ARCH_TIMEOUT value is returned, a timeout occurred 418 before a message could be fetched. */ 419 sys_check_timeouts(); 420 /* We try again to fetch a message from the mbox. */ 421 goto again; 422 } 423 } 424 425 #endif /* NO_SYS */ 426 427 #else /* LWIP_TIMERS && !LWIP_TIMERS_CUSTOM */ 428 /* Satisfy the TCP code which calls this function */ 429 void 430 tcp_timer_needed(void) 431 { 432 } 433 #endif /* LWIP_TIMERS && !LWIP_TIMERS_CUSTOM */ 434