113 lines
3.4 KiB
C
113 lines
3.4 KiB
C
/* $NetBSD: kern_rate.c,v 1.2 2012/12/12 11:10:56 pooka Exp $ */
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/*-
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* Copyright (c) 2000, 2004, 2005, 2007, 2008 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Christopher G. Demetriou.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: kern_rate.c,v 1.2 2012/12/12 11:10:56 pooka Exp $");
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#include <sys/param.h>
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#include <sys/time.h>
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/*
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* ratecheck(): simple time-based rate-limit checking. see ratecheck(9)
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* for usage and rationale.
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*/
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int
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ratecheck(struct timeval *lasttime, const struct timeval *mininterval)
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{
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struct timeval tv, delta;
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int rv = 0;
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getmicrouptime(&tv);
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timersub(&tv, lasttime, &delta);
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/*
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* check for 0,0 is so that the message will be seen at least once,
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* even if interval is huge.
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*/
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if (timercmp(&delta, mininterval, >=) ||
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(lasttime->tv_sec == 0 && lasttime->tv_usec == 0)) {
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*lasttime = tv;
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rv = 1;
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}
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return (rv);
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}
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/*
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* ppsratecheck(): packets (or events) per second limitation.
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*/
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int
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ppsratecheck(struct timeval *lasttime, int *curpps, int maxpps)
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{
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struct timeval tv, delta;
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int rv;
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getmicrouptime(&tv);
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timersub(&tv, lasttime, &delta);
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/*
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* check for 0,0 is so that the message will be seen at least once.
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* if more than one second have passed since the last update of
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* lasttime, reset the counter.
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*
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* we do increment *curpps even in *curpps < maxpps case, as some may
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* try to use *curpps for stat purposes as well.
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*/
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if ((lasttime->tv_sec == 0 && lasttime->tv_usec == 0) ||
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delta.tv_sec >= 1) {
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*lasttime = tv;
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*curpps = 0;
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}
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if (maxpps < 0)
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rv = 1;
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else if (*curpps < maxpps)
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rv = 1;
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else
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rv = 0;
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#if 1 /*DIAGNOSTIC?*/
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/* be careful about wrap-around */
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if (__predict_true(*curpps != INT_MAX))
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*curpps = *curpps + 1;
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#else
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/*
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* assume that there's not too many calls to this function.
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* not sure if the assumption holds, as it depends on *caller's*
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* behavior, not the behavior of this function.
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* IMHO it is wrong to make assumption on the caller's behavior,
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* so the above #if is #if 1, not #ifdef DIAGNOSTIC.
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*/
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*curpps = *curpps + 1;
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#endif
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return (rv);
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}
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