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/* log limiter, for libreswan
*
* Copyright (C) 2022 Andrew Cagney
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version. See <https://www.gnu.org/licenses/gpl2.txt>.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
*/
#include <pthread.h> /* Must be the first include file; XXX: why? */
#include "log_limiter.h"
#include "log.h"
#include "defs.h"
#include "demux.h"
#define RATE_LIMIT 1000
struct limiter {
pthread_mutex_t mutex;
const unsigned limit;
volatile unsigned count;
const char *what;
};
struct limiter log_limiters[LOG_LIMITER_ROOF] = {
[MD_LOG_LIMITER] = {
.limit = RATE_LIMIT,
.what = "message digest",
},
[UNSECURED_LOG_LIMITER] = {
.limit = RATE_LIMIT,
.what = "unsecured message",
},
[CERTIFICATE_LOG_LIMITER] = {
.limit = 10,
.what = "bad certificate",
},
[MSG_ERRQUEUE_LOG_LIMITER] = {
.what = "msg errorqueue",
.limit = RATE_LIMIT,
},
[PAYLOAD_ERRORS_LOG_LIMITER] = {
.what = "payload errors",
.limit = RATE_LIMIT,
},
};
static unsigned log_limit(const struct limiter *limiter)
{
if (impair.log_rate_limit.enabled) {
return impair.log_rate_limit.value;
}
/* --impair log-rate-limit:no */
return limiter->limit;
}
lset_t log_limiter_rc_flags(struct logger *logger, enum log_limiter log_limiter)
{
struct limiter *limiter = &log_limiters[log_limiter];
/* allow imparing to override specified limit */
unsigned limit = log_limit(limiter);
enum limiting {
UNDER_LIMIT,
AT_LIMIT,
OVER_LIMIT,
} limiting;
pthread_mutex_lock(&limiter->mutex);
{
if (limiter->count > limit) {
limiting = OVER_LIMIT;
} else if (limiter->count == limit) {
limiting = AT_LIMIT;
limiter->count++;
} else {
limiting = UNDER_LIMIT;
limiter->count++;
}
}
pthread_mutex_unlock(&limiter->mutex);
switch (limiting) {
case UNDER_LIMIT:
return RC_LOG;
case AT_LIMIT:
llog(RC_LOG, logger,
"%s rate limited log reached limit of %u entries",
limiter->what, limit);
return RC_LOG; /* let this one through */
case OVER_LIMIT:
return (LDBGP(DBG_BASE, logger) ? DEBUG_STREAM : LEMPTY);
}
bad_case(limiting);
}
void limited_llog(struct logger *logger, enum log_limiter log_limiter,
const char *format, ...)
{
lset_t rc_flags = log_limiter_rc_flags(logger, log_limiter);
if (rc_flags != LEMPTY) {
va_list ap;
va_start(ap, format);
llog_va_list(rc_flags, logger, format, ap);
va_end(ap);
}
}
static global_timer_cb reset_log_limiter; /* type check */
static void reset_log_limiter(struct logger *logger)
{
FOR_EACH_ELEMENT(limiter, log_limiters) {
pthread_mutex_lock(&limiter->mutex);
{
if (limiter->count > log_limit(limiter)) {
llog(RC_LOG, logger, "%s rate limited log reset",
limiter->what);
}
limiter->count = 0;
}
pthread_mutex_unlock(&limiter->mutex);
}
}
void init_log_limiter(struct logger *logger)
{
PASSERT(logger, elemsof(log_limiters) == LOG_LIMITER_ROOF);
FOR_EACH_ELEMENT(limiter, log_limiters) {
ldbg(logger, "initializing limiter %td: %s %u",
limiter-log_limiters, limiter->what, limiter->limit);
PASSERT(logger, limiter->what != NULL);
PASSERT(logger, limiter->limit > 0);
pthread_mutex_init(&limiter->mutex, NULL);
}
enable_periodic_timer(EVENT_RESET_LOG_LIMITER,
reset_log_limiter,
RESET_LOG_LIMITER_FREQUENCY);
}
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