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add generic rate limiting support from netbsd; ratelimit is purely time based,

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ppsratecheck is for controlling packets/second

Obtained from:	netbsd
This commit is contained in:
sam 2002-12-20 23:54:47 +00:00
parent d522abfb6d
commit 78550cc698
2 changed files with 90 additions and 0 deletions
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88
sys/kern/kern_time.c
View File

@ -663,3 +663,91 @@ timevalfix(struct timeval *t1)
t1->tv_usec -= 1000000;
}
}
#ifndef timersub
#define timersub(tvp, uvp, vvp) \
do { \
(vvp)->tv_sec = (tvp)->tv_sec - (uvp)->tv_sec; \
(vvp)->tv_usec = (tvp)->tv_usec - (uvp)->tv_usec; \
if ((vvp)->tv_usec < 0) { \
(vvp)->tv_sec--; \
(vvp)->tv_usec += 1000000; \
} \
} while (0)
#endif
/*
* ratecheck(): simple time-based rate-limit checking. see ratecheck(9)
* for usage and rationale.
*/
int
ratecheck(struct timeval *lasttime, const struct timeval *mininterval)
{
struct timeval tv, delta;
int rv = 0;
getmicrouptime(&tv);
timersub(&tv, lasttime, &delta);
/*
* check for 0,0 is so that the message will be seen at least once,
* even if interval is huge.
*/
if (timevalcmp(&delta, mininterval, >=) ||
(lasttime->tv_sec == 0 && lasttime->tv_usec == 0)) {
*lasttime = tv;
rv = 1;
}
return (rv);
}
/*
* ppsratecheck(): packets (or events) per second limitation.
*/
int
ppsratecheck(struct timeval *lasttime, int *curpps, int maxpps)
{
struct timeval tv, delta;
int rv;
getmicrouptime(&tv);
timersub(&tv, lasttime, &delta);
/*
* check for 0,0 is so that the message will be seen at least once.
* if more than one second have passed since the last update of
* lasttime, reset the counter.
*
* we do increment *curpps even in *curpps < maxpps case, as some may
* try to use *curpps for stat purposes as well.
*/
if ((lasttime->tv_sec == 0 && lasttime->tv_usec == 0) ||
delta.tv_sec >= 1) {
*lasttime = tv;
*curpps = 0;
rv = 1;
} else if (maxpps < 0)
rv = 1;
else if (*curpps < maxpps)
rv = 1;
else
rv = 0;
#if 1 /*DIAGNOSTIC?*/
/* be careful about wrap-around */
if (*curpps + 1 > *curpps)
*curpps = *curpps + 1;
#else
/*
* assume that there's not too many calls to this function.
* not sure if the assumption holds, as it depends on *caller's*
* behavior, not the behavior of this function.
* IMHO it is wrong to make assumption on the caller's behavior,
* so the above #if is #if 1, not #ifdef DIAGNOSTIC.
*/
*curpps = *curpps + 1;
#endif
return (rv);
}

2
sys/sys/time.h
View File

@ -302,6 +302,8 @@ void getmicrotime(struct timeval *tvp);
/* Other functions */
int itimerdecr(struct itimerval *itp, int usec);
int itimerfix(struct timeval *tv);
int ppsratecheck(struct timeval *, int *, int);
int ratecheck(struct timeval *, const struct timeval *);
void timevaladd(struct timeval *t1, struct timeval *t2);
void timevalsub(struct timeval *t1, struct timeval *t2);
int tvtohz(struct timeval *tv);