Frantisek Sumsal
9ae50c78cc
When a rate limit is armed, for example via StartLimitInterval=, and the machine is suspended, the rate limit's "clock" is suspended as well, since the elapse checks use CLOCK_MONOTONIC. This then causes unexpected situations where a rate limit armed via StartLimitInterval=1h, followed by a 10 hour suspend, would elapse after 11 hours total. Let's avoid this by switching the rate limits to CLOCK_BOOTTIME, which works the same as CLOCK_MONOTONIC, but accounts for the time spent in suspend as well. There's one slight concern when it comes to upgrade path - the old "begin" value of the rate limit is stored as CLOCK_MONOTONIC, but after upgrading systemd and serializing/deserializing the state it will be suddenly compared against now(CLOCK_BOOTTIME), which might cause some rate limits to elapse "prematurely". But this is just a one-time thing, after which the rate limit timers should re-assess themselves. Resolves: #42912
59 lines
1.3 KiB
C
59 lines
1.3 KiB
C
/* SPDX-License-Identifier: LGPL-2.1-or-later */
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#include "ratelimit.h"
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#include "time-util.h"
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/* Modelled after Linux' lib/ratelimit.c by Dave Young
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* <hidave.darkstar@gmail.com>, which is licensed GPLv2. */
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bool ratelimit_below(RateLimit *rl) {
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usec_t ts;
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assert(rl);
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if (!ratelimit_configured(rl))
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return true;
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ts = now(CLOCK_BOOTTIME);
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if (rl->begin <= 0 ||
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usec_sub_unsigned(ts, rl->begin) > rl->interval) {
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rl->begin = ts; /* Start a new time window */
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rl->num = 1; /* Reset counter */
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return true;
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}
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if (_unlikely_(rl->num == UINT_MAX))
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return false;
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rl->num++;
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return rl->num <= rl->burst;
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}
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unsigned ratelimit_num_dropped(const RateLimit *rl) {
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assert(rl);
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if (rl->num == UINT_MAX) /* overflow, return as special case */
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return UINT_MAX;
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return LESS_BY(rl->num, rl->burst);
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}
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usec_t ratelimit_end(const RateLimit *rl) {
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assert(rl);
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if (rl->begin == 0)
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return 0;
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return usec_add(rl->begin, rl->interval);
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}
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usec_t ratelimit_left(const RateLimit *rl) {
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assert(rl);
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if (rl->begin == 0)
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return 0;
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return usec_sub_unsigned(ratelimit_end(rl), now(CLOCK_BOOTTIME));
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}
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