1 /* 2 * Copyright (c) 1982, 1986, 1989, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)kern_time.c 8.1 (Berkeley) 6/10/93 34 * $FreeBSD: src/sys/kern/kern_time.c,v 1.68.2.1 2002/10/01 08:00:41 bde Exp $ 35 * $DragonFly: src/sys/kern/kern_time.c,v 1.13 2004/01/07 11:08:06 dillon Exp $ 36 */ 37 38 #include <sys/param.h> 39 #include <sys/systm.h> 40 #include <sys/buf.h> 41 #include <sys/sysproto.h> 42 #include <sys/resourcevar.h> 43 #include <sys/signalvar.h> 44 #include <sys/kernel.h> 45 #include <sys/systm.h> 46 #include <sys/sysent.h> 47 #include <sys/sysunion.h> 48 #include <sys/proc.h> 49 #include <sys/time.h> 50 #include <sys/vnode.h> 51 #include <sys/sysctl.h> 52 #include <vm/vm.h> 53 #include <vm/vm_extern.h> 54 #include <sys/msgport2.h> 55 56 struct timezone tz; 57 58 /* 59 * Time of day and interval timer support. 60 * 61 * These routines provide the kernel entry points to get and set 62 * the time-of-day and per-process interval timers. Subroutines 63 * here provide support for adding and subtracting timeval structures 64 * and decrementing interval timers, optionally reloading the interval 65 * timers when they expire. 66 */ 67 68 static int nanosleep1 (struct timespec *rqt, 69 struct timespec *rmt); 70 static int settime (struct timeval *); 71 static void timevalfix (struct timeval *); 72 static void no_lease_updatetime (int); 73 74 static int sleep_hardloop = 0; 75 SYSCTL_INT(_kern, OID_AUTO, sleep_hardloop, CTLFLAG_RW, &sleep_hardloop, 0, ""); 76 77 static void 78 no_lease_updatetime(deltat) 79 int deltat; 80 { 81 } 82 83 void (*lease_updatetime) (int) = no_lease_updatetime; 84 85 static int 86 settime(tv) 87 struct timeval *tv; 88 { 89 struct timeval delta, tv1, tv2; 90 static struct timeval maxtime, laststep; 91 struct timespec ts; 92 int s; 93 94 s = splclock(); 95 microtime(&tv1); 96 delta = *tv; 97 timevalsub(&delta, &tv1); 98 99 /* 100 * If the system is secure, we do not allow the time to be 101 * set to a value earlier than 1 second less than the highest 102 * time we have yet seen. The worst a miscreant can do in 103 * this circumstance is "freeze" time. He couldn't go 104 * back to the past. 105 * 106 * We similarly do not allow the clock to be stepped more 107 * than one second, nor more than once per second. This allows 108 * a miscreant to make the clock march double-time, but no worse. 109 */ 110 if (securelevel > 1) { 111 if (delta.tv_sec < 0 || delta.tv_usec < 0) { 112 /* 113 * Update maxtime to latest time we've seen. 114 */ 115 if (tv1.tv_sec > maxtime.tv_sec) 116 maxtime = tv1; 117 tv2 = *tv; 118 timevalsub(&tv2, &maxtime); 119 if (tv2.tv_sec < -1) { 120 tv->tv_sec = maxtime.tv_sec - 1; 121 printf("Time adjustment clamped to -1 second\n"); 122 } 123 } else { 124 if (tv1.tv_sec == laststep.tv_sec) { 125 splx(s); 126 return (EPERM); 127 } 128 if (delta.tv_sec > 1) { 129 tv->tv_sec = tv1.tv_sec + 1; 130 printf("Time adjustment clamped to +1 second\n"); 131 } 132 laststep = *tv; 133 } 134 } 135 136 ts.tv_sec = tv->tv_sec; 137 ts.tv_nsec = tv->tv_usec * 1000; 138 set_timecounter(&ts); 139 (void) splsoftclock(); 140 lease_updatetime(delta.tv_sec); 141 splx(s); 142 resettodr(); 143 return (0); 144 } 145 146 /* ARGSUSED */ 147 int 148 clock_gettime(struct clock_gettime_args *uap) 149 { 150 struct timespec ats; 151 152 if (SCARG(uap, clock_id) != CLOCK_REALTIME) 153 return (EINVAL); 154 nanotime(&ats); 155 return (copyout(&ats, SCARG(uap, tp), sizeof(ats))); 156 } 157 158 /* ARGSUSED */ 159 int 160 clock_settime(struct clock_settime_args *uap) 161 { 162 struct thread *td = curthread; 163 struct timeval atv; 164 struct timespec ats; 165 int error; 166 167 if ((error = suser(td)) != 0) 168 return (error); 169 if (SCARG(uap, clock_id) != CLOCK_REALTIME) 170 return (EINVAL); 171 if ((error = copyin(SCARG(uap, tp), &ats, sizeof(ats))) != 0) 172 return (error); 173 if (ats.tv_nsec < 0 || ats.tv_nsec >= 1000000000) 174 return (EINVAL); 175 /* XXX Don't convert nsec->usec and back */ 176 TIMESPEC_TO_TIMEVAL(&atv, &ats); 177 if ((error = settime(&atv))) 178 return (error); 179 return (0); 180 } 181 182 int 183 clock_getres(struct clock_getres_args *uap) 184 { 185 struct timespec ts; 186 int error; 187 188 if (SCARG(uap, clock_id) != CLOCK_REALTIME) 189 return (EINVAL); 190 error = 0; 191 if (SCARG(uap, tp)) { 192 ts.tv_sec = 0; 193 /* 194 * Round up the result of the division cheaply by adding 1. 195 * Rounding up is especially important if rounding down 196 * would give 0. Perfect rounding is unimportant. 197 */ 198 ts.tv_nsec = 1000000000 / timecounter->tc_frequency + 1; 199 error = copyout(&ts, SCARG(uap, tp), sizeof(ts)); 200 } 201 return (error); 202 } 203 204 static int nanowait; 205 206 static int 207 nanosleep1(struct timespec *rqt, struct timespec *rmt) 208 { 209 struct timespec ts, ts2, ts3; 210 struct timeval tv; 211 int error; 212 213 if (rqt->tv_nsec < 0 || rqt->tv_nsec >= 1000000000) 214 return (EINVAL); 215 if (rqt->tv_sec < 0 || (rqt->tv_sec == 0 && rqt->tv_nsec == 0)) 216 return (0); 217 nanouptime(&ts); 218 timespecadd(&ts, rqt); /* ts = target timestamp compare */ 219 TIMESPEC_TO_TIMEVAL(&tv, rqt); /* tv = sleep interval */ 220 for (;;) { 221 /* 222 * If hard looping is allowed and the interval is too short, 223 * hard loop with a yield, otherwise sleep with a conservative 224 * tick count. In normal mode sleep with one extra tick count 225 * which will be sufficient for most sleep values. If it 226 * isn't sufficient in normal mode we will wind up doing an 227 * extra loop. 228 * 229 * sleep_hardloop = 0 Normal mode 230 * sleep_hardloop = 1 Strict hard loop 231 * sleep_hardloop = 2 Hard loop on < 1 tick requests only 232 */ 233 int ticks = tvtohz_low(&tv); 234 235 if (sleep_hardloop) { 236 if (ticks == 0) { 237 uio_yield(); 238 error = iscaught(curproc); 239 } else { 240 error = tsleep(&nanowait, PCATCH, "nanslp", 241 ticks + sleep_hardloop - 1); 242 } 243 } else { 244 error = tsleep(&nanowait, PCATCH, "nanslp", ticks + 1); 245 } 246 nanouptime(&ts2); 247 if (error != EWOULDBLOCK) { 248 if (error == ERESTART) 249 error = EINTR; 250 if (rmt != NULL) { 251 timespecsub(&ts, &ts2); 252 if (ts.tv_sec < 0) 253 timespecclear(&ts); 254 *rmt = ts; 255 } 256 return (error); 257 } 258 if (timespeccmp(&ts2, &ts, >=)) 259 return (0); 260 ts3 = ts; 261 timespecsub(&ts3, &ts2); 262 TIMESPEC_TO_TIMEVAL(&tv, &ts3); 263 } 264 } 265 266 static void nanosleep_done(void *arg); 267 static void nanosleep_copyout(union sysunion *sysun); 268 269 /* ARGSUSED */ 270 int 271 nanosleep(struct nanosleep_args *uap) 272 { 273 int error; 274 struct sysmsg_sleep *smsleep = &uap->sysmsg.sm.sleep; 275 276 error = copyin(uap->rqtp, &smsleep->rqt, sizeof(smsleep->rqt)); 277 if (error) 278 return (error); 279 /* 280 * YYY clean this up to always use the callout, note that an abort 281 * implementation should record the residual in the async case. 282 */ 283 if (uap->sysmsg.lmsg.ms_flags & MSGF_ASYNC) { 284 quad_t ticks; 285 286 ticks = (quad_t)smsleep->rqt.tv_nsec * hz / 1000000000LL; 287 if (smsleep->rqt.tv_sec) 288 ticks += (quad_t)smsleep->rqt.tv_sec * hz; 289 if (ticks <= 0) { 290 if (ticks == 0) 291 error = 0; 292 else 293 error = EINVAL; 294 } else { 295 uap->sysmsg.copyout = nanosleep_copyout; 296 callout_init(&smsleep->timer); 297 callout_reset(&smsleep->timer, ticks, nanosleep_done, uap); 298 error = EASYNC; 299 } 300 } else { 301 /* 302 * Old synchronous sleep code, copyout the residual if 303 * nanosleep was interrupted. 304 */ 305 error = nanosleep1(&smsleep->rqt, &smsleep->rmt); 306 if (error && SCARG(uap, rmtp)) 307 error = copyout(&smsleep->rmt, SCARG(uap, rmtp), sizeof(smsleep->rmt)); 308 } 309 return (error); 310 } 311 312 /* 313 * Asynch completion for the nanosleep() syscall. This function may be 314 * called from any context and cannot legally access the originating 315 * thread, proc, or its user space. 316 * 317 * YYY change the callout interface API so we can simply assign the replymsg 318 * function to it directly. 319 */ 320 static void 321 nanosleep_done(void *arg) 322 { 323 struct nanosleep_args *uap = arg; 324 325 lwkt_replymsg(&uap->sysmsg.lmsg, 0); 326 } 327 328 /* 329 * Asynch return for the nanosleep() syscall, called in the context of the 330 * originating thread when it pulls the message off the reply port. This 331 * function is responsible for any copyouts to userland. Kernel threads 332 * which do their own internal system calls will not usually call the return 333 * function. 334 */ 335 static void 336 nanosleep_copyout(union sysunion *sysun) 337 { 338 struct nanosleep_args *uap = &sysun->nanosleep; 339 struct sysmsg_sleep *smsleep = &uap->sysmsg.sm.sleep; 340 341 if (sysun->lmsg.ms_error && uap->rmtp) { 342 sysun->lmsg.ms_error = 343 copyout(&smsleep->rmt, uap->rmtp, sizeof(smsleep->rmt)); 344 } 345 } 346 347 /* ARGSUSED */ 348 int 349 gettimeofday(struct gettimeofday_args *uap) 350 { 351 struct timeval atv; 352 int error = 0; 353 354 if (uap->tp) { 355 microtime(&atv); 356 if ((error = copyout((caddr_t)&atv, (caddr_t)uap->tp, 357 sizeof (atv)))) 358 return (error); 359 } 360 if (uap->tzp) 361 error = copyout((caddr_t)&tz, (caddr_t)uap->tzp, 362 sizeof (tz)); 363 return (error); 364 } 365 366 /* ARGSUSED */ 367 int 368 settimeofday(struct settimeofday_args *uap) 369 { 370 struct thread *td = curthread; 371 struct timeval atv; 372 struct timezone atz; 373 int error; 374 375 if ((error = suser(td))) 376 return (error); 377 /* Verify all parameters before changing time. */ 378 if (uap->tv) { 379 if ((error = copyin((caddr_t)uap->tv, (caddr_t)&atv, 380 sizeof(atv)))) 381 return (error); 382 if (atv.tv_usec < 0 || atv.tv_usec >= 1000000) 383 return (EINVAL); 384 } 385 if (uap->tzp && 386 (error = copyin((caddr_t)uap->tzp, (caddr_t)&atz, sizeof(atz)))) 387 return (error); 388 if (uap->tv && (error = settime(&atv))) 389 return (error); 390 if (uap->tzp) 391 tz = atz; 392 return (0); 393 } 394 395 int tickdelta; /* current clock skew, us. per tick */ 396 long timedelta; /* unapplied time correction, us. */ 397 static long bigadj = 1000000; /* use 10x skew above bigadj us. */ 398 399 /* ARGSUSED */ 400 int 401 adjtime(struct adjtime_args *uap) 402 { 403 struct thread *td = curthread; 404 struct timeval atv; 405 long ndelta, ntickdelta, odelta; 406 int s, error; 407 408 if ((error = suser(td))) 409 return (error); 410 if ((error = 411 copyin((caddr_t)uap->delta, (caddr_t)&atv, sizeof(struct timeval)))) 412 return (error); 413 414 /* 415 * Compute the total correction and the rate at which to apply it. 416 * Round the adjustment down to a whole multiple of the per-tick 417 * delta, so that after some number of incremental changes in 418 * hardclock(), tickdelta will become zero, lest the correction 419 * overshoot and start taking us away from the desired final time. 420 */ 421 ndelta = atv.tv_sec * 1000000 + atv.tv_usec; 422 if (ndelta > bigadj || ndelta < -bigadj) 423 ntickdelta = 10 * tickadj; 424 else 425 ntickdelta = tickadj; 426 if (ndelta % ntickdelta) 427 ndelta = ndelta / ntickdelta * ntickdelta; 428 429 /* 430 * To make hardclock()'s job easier, make the per-tick delta negative 431 * if we want time to run slower; then hardclock can simply compute 432 * tick + tickdelta, and subtract tickdelta from timedelta. 433 */ 434 if (ndelta < 0) 435 ntickdelta = -ntickdelta; 436 s = splclock(); 437 odelta = timedelta; 438 timedelta = ndelta; 439 tickdelta = ntickdelta; 440 splx(s); 441 442 if (uap->olddelta) { 443 atv.tv_sec = odelta / 1000000; 444 atv.tv_usec = odelta % 1000000; 445 (void) copyout((caddr_t)&atv, (caddr_t)uap->olddelta, 446 sizeof(struct timeval)); 447 } 448 return (0); 449 } 450 451 /* 452 * Get value of an interval timer. The process virtual and 453 * profiling virtual time timers are kept in the p_stats area, since 454 * they can be swapped out. These are kept internally in the 455 * way they are specified externally: in time until they expire. 456 * 457 * The real time interval timer is kept in the process table slot 458 * for the process, and its value (it_value) is kept as an 459 * absolute time rather than as a delta, so that it is easy to keep 460 * periodic real-time signals from drifting. 461 * 462 * Virtual time timers are processed in the hardclock() routine of 463 * kern_clock.c. The real time timer is processed by a timeout 464 * routine, called from the softclock() routine. Since a callout 465 * may be delayed in real time due to interrupt processing in the system, 466 * it is possible for the real time timeout routine (realitexpire, given below), 467 * to be delayed in real time past when it is supposed to occur. It 468 * does not suffice, therefore, to reload the real timer .it_value from the 469 * real time timers .it_interval. Rather, we compute the next time in 470 * absolute time the timer should go off. 471 */ 472 /* ARGSUSED */ 473 int 474 getitimer(struct getitimer_args *uap) 475 { 476 struct proc *p = curproc; 477 struct timeval ctv; 478 struct itimerval aitv; 479 int s; 480 481 if (uap->which > ITIMER_PROF) 482 return (EINVAL); 483 s = splclock(); /* XXX still needed ? */ 484 if (uap->which == ITIMER_REAL) { 485 /* 486 * Convert from absolute to relative time in .it_value 487 * part of real time timer. If time for real time timer 488 * has passed return 0, else return difference between 489 * current time and time for the timer to go off. 490 */ 491 aitv = p->p_realtimer; 492 if (timevalisset(&aitv.it_value)) { 493 getmicrouptime(&ctv); 494 if (timevalcmp(&aitv.it_value, &ctv, <)) 495 timevalclear(&aitv.it_value); 496 else 497 timevalsub(&aitv.it_value, &ctv); 498 } 499 } else 500 aitv = p->p_stats->p_timer[uap->which]; 501 splx(s); 502 return (copyout((caddr_t)&aitv, (caddr_t)uap->itv, 503 sizeof (struct itimerval))); 504 } 505 506 /* ARGSUSED */ 507 int 508 setitimer(struct setitimer_args *uap) 509 { 510 struct itimerval aitv; 511 struct timeval ctv; 512 struct itimerval *itvp; 513 struct proc *p = curproc; 514 int s, error; 515 516 if (uap->which > ITIMER_PROF) 517 return (EINVAL); 518 itvp = uap->itv; 519 if (itvp && (error = copyin((caddr_t)itvp, (caddr_t)&aitv, 520 sizeof(struct itimerval)))) 521 return (error); 522 if ((uap->itv = uap->oitv) && 523 (error = getitimer((struct getitimer_args *)uap))) 524 return (error); 525 if (itvp == 0) 526 return (0); 527 if (itimerfix(&aitv.it_value)) 528 return (EINVAL); 529 if (!timevalisset(&aitv.it_value)) 530 timevalclear(&aitv.it_interval); 531 else if (itimerfix(&aitv.it_interval)) 532 return (EINVAL); 533 s = splclock(); /* XXX: still needed ? */ 534 if (uap->which == ITIMER_REAL) { 535 if (timevalisset(&p->p_realtimer.it_value)) 536 untimeout(realitexpire, (caddr_t)p, p->p_ithandle); 537 if (timevalisset(&aitv.it_value)) 538 p->p_ithandle = timeout(realitexpire, (caddr_t)p, 539 tvtohz_high(&aitv.it_value)); 540 getmicrouptime(&ctv); 541 timevaladd(&aitv.it_value, &ctv); 542 p->p_realtimer = aitv; 543 } else 544 p->p_stats->p_timer[uap->which] = aitv; 545 splx(s); 546 return (0); 547 } 548 549 /* 550 * Real interval timer expired: 551 * send process whose timer expired an alarm signal. 552 * If time is not set up to reload, then just return. 553 * Else compute next time timer should go off which is > current time. 554 * This is where delay in processing this timeout causes multiple 555 * SIGALRM calls to be compressed into one. 556 * tvtohz_high() always adds 1 to allow for the time until the next clock 557 * interrupt being strictly less than 1 clock tick, but we don't want 558 * that here since we want to appear to be in sync with the clock 559 * interrupt even when we're delayed. 560 */ 561 void 562 realitexpire(arg) 563 void *arg; 564 { 565 struct proc *p; 566 struct timeval ctv, ntv; 567 int s; 568 569 p = (struct proc *)arg; 570 psignal(p, SIGALRM); 571 if (!timevalisset(&p->p_realtimer.it_interval)) { 572 timevalclear(&p->p_realtimer.it_value); 573 return; 574 } 575 for (;;) { 576 s = splclock(); /* XXX: still neeeded ? */ 577 timevaladd(&p->p_realtimer.it_value, 578 &p->p_realtimer.it_interval); 579 getmicrouptime(&ctv); 580 if (timevalcmp(&p->p_realtimer.it_value, &ctv, >)) { 581 ntv = p->p_realtimer.it_value; 582 timevalsub(&ntv, &ctv); 583 p->p_ithandle = timeout(realitexpire, (caddr_t)p, 584 tvtohz_low(&ntv)); 585 splx(s); 586 return; 587 } 588 splx(s); 589 } 590 } 591 592 /* 593 * Check that a proposed value to load into the .it_value or 594 * .it_interval part of an interval timer is acceptable, and 595 * fix it to have at least minimal value (i.e. if it is less 596 * than the resolution of the clock, round it up.) 597 */ 598 int 599 itimerfix(tv) 600 struct timeval *tv; 601 { 602 603 if (tv->tv_sec < 0 || tv->tv_sec > 100000000 || 604 tv->tv_usec < 0 || tv->tv_usec >= 1000000) 605 return (EINVAL); 606 if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick) 607 tv->tv_usec = tick; 608 return (0); 609 } 610 611 /* 612 * Decrement an interval timer by a specified number 613 * of microseconds, which must be less than a second, 614 * i.e. < 1000000. If the timer expires, then reload 615 * it. In this case, carry over (usec - old value) to 616 * reduce the value reloaded into the timer so that 617 * the timer does not drift. This routine assumes 618 * that it is called in a context where the timers 619 * on which it is operating cannot change in value. 620 */ 621 int 622 itimerdecr(itp, usec) 623 struct itimerval *itp; 624 int usec; 625 { 626 627 if (itp->it_value.tv_usec < usec) { 628 if (itp->it_value.tv_sec == 0) { 629 /* expired, and already in next interval */ 630 usec -= itp->it_value.tv_usec; 631 goto expire; 632 } 633 itp->it_value.tv_usec += 1000000; 634 itp->it_value.tv_sec--; 635 } 636 itp->it_value.tv_usec -= usec; 637 usec = 0; 638 if (timevalisset(&itp->it_value)) 639 return (1); 640 /* expired, exactly at end of interval */ 641 expire: 642 if (timevalisset(&itp->it_interval)) { 643 itp->it_value = itp->it_interval; 644 itp->it_value.tv_usec -= usec; 645 if (itp->it_value.tv_usec < 0) { 646 itp->it_value.tv_usec += 1000000; 647 itp->it_value.tv_sec--; 648 } 649 } else 650 itp->it_value.tv_usec = 0; /* sec is already 0 */ 651 return (0); 652 } 653 654 /* 655 * Add and subtract routines for timevals. 656 * N.B.: subtract routine doesn't deal with 657 * results which are before the beginning, 658 * it just gets very confused in this case. 659 * Caveat emptor. 660 */ 661 void 662 timevaladd(t1, t2) 663 struct timeval *t1, *t2; 664 { 665 666 t1->tv_sec += t2->tv_sec; 667 t1->tv_usec += t2->tv_usec; 668 timevalfix(t1); 669 } 670 671 void 672 timevalsub(t1, t2) 673 struct timeval *t1, *t2; 674 { 675 676 t1->tv_sec -= t2->tv_sec; 677 t1->tv_usec -= t2->tv_usec; 678 timevalfix(t1); 679 } 680 681 static void 682 timevalfix(t1) 683 struct timeval *t1; 684 { 685 686 if (t1->tv_usec < 0) { 687 t1->tv_sec--; 688 t1->tv_usec += 1000000; 689 } 690 if (t1->tv_usec >= 1000000) { 691 t1->tv_sec++; 692 t1->tv_usec -= 1000000; 693 } 694 } 695 696 /* 697 * ratecheck(): simple time-based rate-limit checking. 698 */ 699 int 700 ratecheck(struct timeval *lasttime, const struct timeval *mininterval) 701 { 702 struct timeval tv, delta; 703 int rv = 0; 704 705 getmicrouptime(&tv); /* NB: 10ms precision */ 706 delta = tv; 707 timevalsub(&delta, lasttime); 708 709 /* 710 * check for 0,0 is so that the message will be seen at least once, 711 * even if interval is huge. 712 */ 713 if (timevalcmp(&delta, mininterval, >=) || 714 (lasttime->tv_sec == 0 && lasttime->tv_usec == 0)) { 715 *lasttime = tv; 716 rv = 1; 717 } 718 719 return (rv); 720 } 721 722 /* 723 * ppsratecheck(): packets (or events) per second limitation. 724 * 725 * Return 0 if the limit is to be enforced (e.g. the caller 726 * should drop a packet because of the rate limitation). 727 * 728 * maxpps of 0 always causes zero to be returned. maxpps of -1 729 * always causes 1 to be returned; this effectively defeats rate 730 * limiting. 731 * 732 * Note that we maintain the struct timeval for compatibility 733 * with other bsd systems. We reuse the storage and just monitor 734 * clock ticks for minimal overhead. 735 */ 736 int 737 ppsratecheck(struct timeval *lasttime, int *curpps, int maxpps) 738 { 739 int now; 740 741 /* 742 * Reset the last time and counter if this is the first call 743 * or more than a second has passed since the last update of 744 * lasttime. 745 */ 746 now = ticks; 747 if (lasttime->tv_sec == 0 || (u_int)(now - lasttime->tv_sec) >= hz) { 748 lasttime->tv_sec = now; 749 *curpps = 1; 750 return (maxpps != 0); 751 } else { 752 (*curpps)++; /* NB: ignore potential overflow */ 753 return (maxpps < 0 || *curpps < maxpps); 754 } 755 } 756 757