diff options
Diffstat (limited to 'libevent-2.0.20-stable/bufferevent_ratelim.c')
| -rw-r--r-- | libevent-2.0.20-stable/bufferevent_ratelim.c | 1011 |
1 files changed, 1011 insertions, 0 deletions
diff --git a/libevent-2.0.20-stable/bufferevent_ratelim.c b/libevent-2.0.20-stable/bufferevent_ratelim.c new file mode 100644 index 0000000..7965390 --- /dev/null +++ b/libevent-2.0.20-stable/bufferevent_ratelim.c @@ -0,0 +1,1011 @@ +/* + * Copyright (c) 2007-2012 Niels Provos and Nick Mathewson + * Copyright (c) 2002-2006 Niels Provos <provos@citi.umich.edu> + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. The name of the author may not be used to endorse or promote products + * derived from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include <sys/types.h> +#include <limits.h> +#include <string.h> +#include <stdlib.h> + +#include "event2/event.h" +#include "event2/event_struct.h" +#include "event2/util.h" +#include "event2/bufferevent.h" +#include "event2/bufferevent_struct.h" +#include "event2/buffer.h" + +#include "ratelim-internal.h" + +#include "bufferevent-internal.h" +#include "mm-internal.h" +#include "util-internal.h" +#include "event-internal.h" + +int +ev_token_bucket_init(struct ev_token_bucket *bucket, + const struct ev_token_bucket_cfg *cfg, + ev_uint32_t current_tick, + int reinitialize) +{ + if (reinitialize) { + /* on reinitialization, we only clip downwards, since we've + already used who-knows-how-much bandwidth this tick. We + leave "last_updated" as it is; the next update will add the + appropriate amount of bandwidth to the bucket. + */ + if (bucket->read_limit > (ev_int64_t) cfg->read_maximum) + bucket->read_limit = cfg->read_maximum; + if (bucket->write_limit > (ev_int64_t) cfg->write_maximum) + bucket->write_limit = cfg->write_maximum; + } else { + bucket->read_limit = cfg->read_rate; + bucket->write_limit = cfg->write_rate; + bucket->last_updated = current_tick; + } + return 0; +} + +int +ev_token_bucket_update(struct ev_token_bucket *bucket, + const struct ev_token_bucket_cfg *cfg, + ev_uint32_t current_tick) +{ + /* It's okay if the tick number overflows, since we'll just + * wrap around when we do the unsigned substraction. */ + unsigned n_ticks = current_tick - bucket->last_updated; + + /* Make sure some ticks actually happened, and that time didn't + * roll back. */ + if (n_ticks == 0 || n_ticks > INT_MAX) + return 0; + + /* Naively, we would say + bucket->limit += n_ticks * cfg->rate; + + if (bucket->limit > cfg->maximum) + bucket->limit = cfg->maximum; + + But we're worried about overflow, so we do it like this: + */ + + if ((cfg->read_maximum - bucket->read_limit) / n_ticks < cfg->read_rate) + bucket->read_limit = cfg->read_maximum; + else + bucket->read_limit += n_ticks * cfg->read_rate; + + + if ((cfg->write_maximum - bucket->write_limit) / n_ticks < cfg->write_rate) + bucket->write_limit = cfg->write_maximum; + else + bucket->write_limit += n_ticks * cfg->write_rate; + + + bucket->last_updated = current_tick; + + return 1; +} + +static inline void +bufferevent_update_buckets(struct bufferevent_private *bev) +{ + /* Must hold lock on bev. */ + struct timeval now; + unsigned tick; + event_base_gettimeofday_cached(bev->bev.ev_base, &now); + tick = ev_token_bucket_get_tick(&now, bev->rate_limiting->cfg); + if (tick != bev->rate_limiting->limit.last_updated) + ev_token_bucket_update(&bev->rate_limiting->limit, + bev->rate_limiting->cfg, tick); +} + +ev_uint32_t +ev_token_bucket_get_tick(const struct timeval *tv, + const struct ev_token_bucket_cfg *cfg) +{ + /* This computation uses two multiplies and a divide. We could do + * fewer if we knew that the tick length was an integer number of + * seconds, or if we knew it divided evenly into a second. We should + * investigate that more. + */ + + /* We cast to an ev_uint64_t first, since we don't want to overflow + * before we do the final divide. */ + ev_uint64_t msec = (ev_uint64_t)tv->tv_sec * 1000 + tv->tv_usec / 1000; + return (unsigned)(msec / cfg->msec_per_tick); +} + +struct ev_token_bucket_cfg * +ev_token_bucket_cfg_new(size_t read_rate, size_t read_burst, + size_t write_rate, size_t write_burst, + const struct timeval *tick_len) +{ + struct ev_token_bucket_cfg *r; + struct timeval g; + if (! tick_len) { + g.tv_sec = 1; + g.tv_usec = 0; + tick_len = &g; + } + if (read_rate > read_burst || write_rate > write_burst || + read_rate < 1 || write_rate < 1) + return NULL; + if (read_rate > EV_RATE_LIMIT_MAX || + write_rate > EV_RATE_LIMIT_MAX || + read_burst > EV_RATE_LIMIT_MAX || + write_burst > EV_RATE_LIMIT_MAX) + return NULL; + r = mm_calloc(1, sizeof(struct ev_token_bucket_cfg)); + if (!r) + return NULL; + r->read_rate = read_rate; + r->write_rate = write_rate; + r->read_maximum = read_burst; + r->write_maximum = write_burst; + memcpy(&r->tick_timeout, tick_len, sizeof(struct timeval)); + r->msec_per_tick = (tick_len->tv_sec * 1000) + + (tick_len->tv_usec & COMMON_TIMEOUT_MICROSECONDS_MASK)/1000; + return r; +} + +void +ev_token_bucket_cfg_free(struct ev_token_bucket_cfg *cfg) +{ + mm_free(cfg); +} + +/* No matter how big our bucket gets, don't try to read more than this + * much in a single read operation. */ +#define MAX_TO_READ_EVER 16384 +/* No matter how big our bucket gets, don't try to write more than this + * much in a single write operation. */ +#define MAX_TO_WRITE_EVER 16384 + +#define LOCK_GROUP(g) EVLOCK_LOCK((g)->lock, 0) +#define UNLOCK_GROUP(g) EVLOCK_UNLOCK((g)->lock, 0) + +static int _bev_group_suspend_reading(struct bufferevent_rate_limit_group *g); +static int _bev_group_suspend_writing(struct bufferevent_rate_limit_group *g); +static void _bev_group_unsuspend_reading(struct bufferevent_rate_limit_group *g); +static void _bev_group_unsuspend_writing(struct bufferevent_rate_limit_group *g); + +/** Helper: figure out the maximum amount we should write if is_write, or + the maximum amount we should read if is_read. Return that maximum, or + 0 if our bucket is wholly exhausted. + */ +static inline ev_ssize_t +_bufferevent_get_rlim_max(struct bufferevent_private *bev, int is_write) +{ + /* needs lock on bev. */ + ev_ssize_t max_so_far = is_write?MAX_TO_WRITE_EVER:MAX_TO_READ_EVER; + +#define LIM(x) \ + (is_write ? (x).write_limit : (x).read_limit) + +#define GROUP_SUSPENDED(g) \ + (is_write ? (g)->write_suspended : (g)->read_suspended) + + /* Sets max_so_far to MIN(x, max_so_far) */ +#define CLAMPTO(x) \ + do { \ + if (max_so_far > (x)) \ + max_so_far = (x); \ + } while (0); + + if (!bev->rate_limiting) + return max_so_far; + + /* If rate-limiting is enabled at all, update the appropriate + bucket, and take the smaller of our rate limit and the group + rate limit. + */ + + if (bev->rate_limiting->cfg) { + bufferevent_update_buckets(bev); + max_so_far = LIM(bev->rate_limiting->limit); + } + if (bev->rate_limiting->group) { + struct bufferevent_rate_limit_group *g = + bev->rate_limiting->group; + ev_ssize_t share; + LOCK_GROUP(g); + if (GROUP_SUSPENDED(g)) { + /* We can get here if we failed to lock this + * particular bufferevent while suspending the whole + * group. */ + if (is_write) + bufferevent_suspend_write(&bev->bev, + BEV_SUSPEND_BW_GROUP); + else + bufferevent_suspend_read(&bev->bev, + BEV_SUSPEND_BW_GROUP); + share = 0; + } else { + /* XXXX probably we should divide among the active + * members, not the total members. */ + share = LIM(g->rate_limit) / g->n_members; + if (share < g->min_share) + share = g->min_share; + } + UNLOCK_GROUP(g); + CLAMPTO(share); + } + + if (max_so_far < 0) + max_so_far = 0; + return max_so_far; +} + +ev_ssize_t +_bufferevent_get_read_max(struct bufferevent_private *bev) +{ + return _bufferevent_get_rlim_max(bev, 0); +} + +ev_ssize_t +_bufferevent_get_write_max(struct bufferevent_private *bev) +{ + return _bufferevent_get_rlim_max(bev, 1); +} + +int +_bufferevent_decrement_read_buckets(struct bufferevent_private *bev, ev_ssize_t bytes) +{ + /* XXXXX Make sure all users of this function check its return value */ + int r = 0; + /* need to hold lock on bev */ + if (!bev->rate_limiting) + return 0; + + if (bev->rate_limiting->cfg) { + bev->rate_limiting->limit.read_limit -= bytes; + if (bev->rate_limiting->limit.read_limit <= 0) { + bufferevent_suspend_read(&bev->bev, BEV_SUSPEND_BW); + if (event_add(&bev->rate_limiting->refill_bucket_event, + &bev->rate_limiting->cfg->tick_timeout) < 0) + r = -1; + } else if (bev->read_suspended & BEV_SUSPEND_BW) { + if (!(bev->write_suspended & BEV_SUSPEND_BW)) + event_del(&bev->rate_limiting->refill_bucket_event); + bufferevent_unsuspend_read(&bev->bev, BEV_SUSPEND_BW); + } + } + + if (bev->rate_limiting->group) { + LOCK_GROUP(bev->rate_limiting->group); + bev->rate_limiting->group->rate_limit.read_limit -= bytes; + bev->rate_limiting->group->total_read += bytes; + if (bev->rate_limiting->group->rate_limit.read_limit <= 0) { + _bev_group_suspend_reading(bev->rate_limiting->group); + } else if (bev->rate_limiting->group->read_suspended) { + _bev_group_unsuspend_reading(bev->rate_limiting->group); + } + UNLOCK_GROUP(bev->rate_limiting->group); + } + + return r; +} + +int +_bufferevent_decrement_write_buckets(struct bufferevent_private *bev, ev_ssize_t bytes) +{ + /* XXXXX Make sure all users of this function check its return value */ + int r = 0; + /* need to hold lock */ + if (!bev->rate_limiting) + return 0; + + if (bev->rate_limiting->cfg) { + bev->rate_limiting->limit.write_limit -= bytes; + if (bev->rate_limiting->limit.write_limit <= 0) { + bufferevent_suspend_write(&bev->bev, BEV_SUSPEND_BW); + if (event_add(&bev->rate_limiting->refill_bucket_event, + &bev->rate_limiting->cfg->tick_timeout) < 0) + r = -1; + } else if (bev->write_suspended & BEV_SUSPEND_BW) { + if (!(bev->read_suspended & BEV_SUSPEND_BW)) + event_del(&bev->rate_limiting->refill_bucket_event); + bufferevent_unsuspend_write(&bev->bev, BEV_SUSPEND_BW); + } + } + + if (bev->rate_limiting->group) { + LOCK_GROUP(bev->rate_limiting->group); + bev->rate_limiting->group->rate_limit.write_limit -= bytes; + bev->rate_limiting->group->total_written += bytes; + if (bev->rate_limiting->group->rate_limit.write_limit <= 0) { + _bev_group_suspend_writing(bev->rate_limiting->group); + } else if (bev->rate_limiting->group->write_suspended) { + _bev_group_unsuspend_writing(bev->rate_limiting->group); + } + UNLOCK_GROUP(bev->rate_limiting->group); + } + + return r; +} + +/** Stop reading on every bufferevent in <b>g</b> */ +static int +_bev_group_suspend_reading(struct bufferevent_rate_limit_group *g) +{ + /* Needs group lock */ + struct bufferevent_private *bev; + g->read_suspended = 1; + g->pending_unsuspend_read = 0; + + /* Note that in this loop we call EVLOCK_TRY_LOCK instead of BEV_LOCK, + to prevent a deadlock. (Ordinarily, the group lock nests inside + the bufferevent locks. If we are unable to lock any individual + bufferevent, it will find out later when it looks at its limit + and sees that its group is suspended. + */ + TAILQ_FOREACH(bev, &g->members, rate_limiting->next_in_group) { + if (EVLOCK_TRY_LOCK(bev->lock)) { + bufferevent_suspend_read(&bev->bev, + BEV_SUSPEND_BW_GROUP); + EVLOCK_UNLOCK(bev->lock, 0); + } + } + return 0; +} + +/** Stop writing on every bufferevent in <b>g</b> */ +static int +_bev_group_suspend_writing(struct bufferevent_rate_limit_group *g) +{ + /* Needs group lock */ + struct bufferevent_private *bev; + g->write_suspended = 1; + g->pending_unsuspend_write = 0; + TAILQ_FOREACH(bev, &g->members, rate_limiting->next_in_group) { + if (EVLOCK_TRY_LOCK(bev->lock)) { + bufferevent_suspend_write(&bev->bev, + BEV_SUSPEND_BW_GROUP); + EVLOCK_UNLOCK(bev->lock, 0); + } + } + return 0; +} + +/** Timer callback invoked on a single bufferevent with one or more exhausted + buckets when they are ready to refill. */ +static void +_bev_refill_callback(evutil_socket_t fd, short what, void *arg) +{ + unsigned tick; + struct timeval now; + struct bufferevent_private *bev = arg; + int again = 0; + BEV_LOCK(&bev->bev); + if (!bev->rate_limiting || !bev->rate_limiting->cfg) { + BEV_UNLOCK(&bev->bev); + return; + } + + /* First, update the bucket */ + event_base_gettimeofday_cached(bev->bev.ev_base, &now); + tick = ev_token_bucket_get_tick(&now, + bev->rate_limiting->cfg); + ev_token_bucket_update(&bev->rate_limiting->limit, + bev->rate_limiting->cfg, + tick); + + /* Now unsuspend any read/write operations as appropriate. */ + if ((bev->read_suspended & BEV_SUSPEND_BW)) { + if (bev->rate_limiting->limit.read_limit > 0) + bufferevent_unsuspend_read(&bev->bev, BEV_SUSPEND_BW); + else + again = 1; + } + if ((bev->write_suspended & BEV_SUSPEND_BW)) { + if (bev->rate_limiting->limit.write_limit > 0) + bufferevent_unsuspend_write(&bev->bev, BEV_SUSPEND_BW); + else + again = 1; + } + if (again) { + /* One or more of the buckets may need another refill if they + started negative. + + XXXX if we need to be quiet for more ticks, we should + maybe figure out what timeout we really want. + */ + /* XXXX Handle event_add failure somehow */ + event_add(&bev->rate_limiting->refill_bucket_event, + &bev->rate_limiting->cfg->tick_timeout); + } + BEV_UNLOCK(&bev->bev); +} + +/** Helper: grab a random element from a bufferevent group. */ +static struct bufferevent_private * +_bev_group_random_element(struct bufferevent_rate_limit_group *group) +{ + int which; + struct bufferevent_private *bev; + + /* requires group lock */ + + if (!group->n_members) + return NULL; + + EVUTIL_ASSERT(! TAILQ_EMPTY(&group->members)); + + which = _evutil_weakrand() % group->n_members; + + bev = TAILQ_FIRST(&group->members); + while (which--) + bev = TAILQ_NEXT(bev, rate_limiting->next_in_group); + + return bev; +} + +/** Iterate over the elements of a rate-limiting group 'g' with a random + starting point, assigning each to the variable 'bev', and executing the + block 'block'. + + We do this in a half-baked effort to get fairness among group members. + XXX Round-robin or some kind of priority queue would be even more fair. + */ +#define FOREACH_RANDOM_ORDER(block) \ + do { \ + first = _bev_group_random_element(g); \ + for (bev = first; bev != TAILQ_END(&g->members); \ + bev = TAILQ_NEXT(bev, rate_limiting->next_in_group)) { \ + block ; \ + } \ + for (bev = TAILQ_FIRST(&g->members); bev && bev != first; \ + bev = TAILQ_NEXT(bev, rate_limiting->next_in_group)) { \ + block ; \ + } \ + } while (0) + +static void +_bev_group_unsuspend_reading(struct bufferevent_rate_limit_group *g) +{ + int again = 0; + struct bufferevent_private *bev, *first; + + g->read_suspended = 0; + FOREACH_RANDOM_ORDER({ + if (EVLOCK_TRY_LOCK(bev->lock)) { + bufferevent_unsuspend_read(&bev->bev, + BEV_SUSPEND_BW_GROUP); + EVLOCK_UNLOCK(bev->lock, 0); + } else { + again = 1; + } + }); + g->pending_unsuspend_read = again; +} + +static void +_bev_group_unsuspend_writing(struct bufferevent_rate_limit_group *g) +{ + int again = 0; + struct bufferevent_private *bev, *first; + g->write_suspended = 0; + + FOREACH_RANDOM_ORDER({ + if (EVLOCK_TRY_LOCK(bev->lock)) { + bufferevent_unsuspend_write(&bev->bev, + BEV_SUSPEND_BW_GROUP); + EVLOCK_UNLOCK(bev->lock, 0); + } else { + again = 1; + } + }); + g->pending_unsuspend_write = again; +} + +/** Callback invoked every tick to add more elements to the group bucket + and unsuspend group members as needed. + */ +static void +_bev_group_refill_callback(evutil_socket_t fd, short what, void *arg) +{ + struct bufferevent_rate_limit_group *g = arg; + unsigned tick; + struct timeval now; + + event_base_gettimeofday_cached(event_get_base(&g->master_refill_event), &now); + + LOCK_GROUP(g); + + tick = ev_token_bucket_get_tick(&now, &g->rate_limit_cfg); + ev_token_bucket_update(&g->rate_limit, &g->rate_limit_cfg, tick); + + if (g->pending_unsuspend_read || + (g->read_suspended && (g->rate_limit.read_limit >= g->min_share))) { + _bev_group_unsuspend_reading(g); + } + if (g->pending_unsuspend_write || + (g->write_suspended && (g->rate_limit.write_limit >= g->min_share))){ + _bev_group_unsuspend_writing(g); + } + + /* XXXX Rather than waiting to the next tick to unsuspend stuff + * with pending_unsuspend_write/read, we should do it on the + * next iteration of the mainloop. + */ + + UNLOCK_GROUP(g); +} + +int +bufferevent_set_rate_limit(struct bufferevent *bev, + struct ev_token_bucket_cfg *cfg) +{ + struct bufferevent_private *bevp = + EVUTIL_UPCAST(bev, struct bufferevent_private, bev); + int r = -1; + struct bufferevent_rate_limit *rlim; + struct timeval now; + ev_uint32_t tick; + int reinit = 0, suspended = 0; + /* XXX reference-count cfg */ + + BEV_LOCK(bev); + + if (cfg == NULL) { + if (bevp->rate_limiting) { + rlim = bevp->rate_limiting; + rlim->cfg = NULL; + bufferevent_unsuspend_read(bev, BEV_SUSPEND_BW); + bufferevent_unsuspend_write(bev, BEV_SUSPEND_BW); + if (event_initialized(&rlim->refill_bucket_event)) + event_del(&rlim->refill_bucket_event); + } + r = 0; + goto done; + } + + event_base_gettimeofday_cached(bev->ev_base, &now); + tick = ev_token_bucket_get_tick(&now, cfg); + + if (bevp->rate_limiting && bevp->rate_limiting->cfg == cfg) { + /* no-op */ + r = 0; + goto done; + } + if (bevp->rate_limiting == NULL) { + rlim = mm_calloc(1, sizeof(struct bufferevent_rate_limit)); + if (!rlim) + goto done; + bevp->rate_limiting = rlim; + } else { + rlim = bevp->rate_limiting; + } + reinit = rlim->cfg != NULL; + + rlim->cfg = cfg; + ev_token_bucket_init(&rlim->limit, cfg, tick, reinit); + + if (reinit) { + EVUTIL_ASSERT(event_initialized(&rlim->refill_bucket_event)); + event_del(&rlim->refill_bucket_event); + } + evtimer_assign(&rlim->refill_bucket_event, bev->ev_base, + _bev_refill_callback, bevp); + + if (rlim->limit.read_limit > 0) { + bufferevent_unsuspend_read(bev, BEV_SUSPEND_BW); + } else { + bufferevent_suspend_read(bev, BEV_SUSPEND_BW); + suspended=1; + } + if (rlim->limit.write_limit > 0) { + bufferevent_unsuspend_write(bev, BEV_SUSPEND_BW); + } else { + bufferevent_suspend_write(bev, BEV_SUSPEND_BW); + suspended = 1; + } + + if (suspended) + event_add(&rlim->refill_bucket_event, &cfg->tick_timeout); + + r = 0; + +done: + BEV_UNLOCK(bev); + return r; +} + +struct bufferevent_rate_limit_group * +bufferevent_rate_limit_group_new(struct event_base *base, + const struct ev_token_bucket_cfg *cfg) +{ + struct bufferevent_rate_limit_group *g; + struct timeval now; + ev_uint32_t tick; + + event_base_gettimeofday_cached(base, &now); + tick = ev_token_bucket_get_tick(&now, cfg); + + g = mm_calloc(1, sizeof(struct bufferevent_rate_limit_group)); + if (!g) + return NULL; + memcpy(&g->rate_limit_cfg, cfg, sizeof(g->rate_limit_cfg)); + TAILQ_INIT(&g->members); + + ev_token_bucket_init(&g->rate_limit, cfg, tick, 0); + + event_assign(&g->master_refill_event, base, -1, EV_PERSIST, + _bev_group_refill_callback, g); + /*XXXX handle event_add failure */ + event_add(&g->master_refill_event, &cfg->tick_timeout); + + EVTHREAD_ALLOC_LOCK(g->lock, EVTHREAD_LOCKTYPE_RECURSIVE); + + bufferevent_rate_limit_group_set_min_share(g, 64); + + return g; +} + +int +bufferevent_rate_limit_group_set_cfg( + struct bufferevent_rate_limit_group *g, + const struct ev_token_bucket_cfg *cfg) +{ + int same_tick; + if (!g || !cfg) + return -1; + + LOCK_GROUP(g); + same_tick = evutil_timercmp( + &g->rate_limit_cfg.tick_timeout, &cfg->tick_timeout, ==); + memcpy(&g->rate_limit_cfg, cfg, sizeof(g->rate_limit_cfg)); + + if (g->rate_limit.read_limit > (ev_ssize_t)cfg->read_maximum) + g->rate_limit.read_limit = cfg->read_maximum; + if (g->rate_limit.write_limit > (ev_ssize_t)cfg->write_maximum) + g->rate_limit.write_limit = cfg->write_maximum; + + if (!same_tick) { + /* This can cause a hiccup in the schedule */ + event_add(&g->master_refill_event, &cfg->tick_timeout); + } + + /* The new limits might force us to adjust min_share differently. */ + bufferevent_rate_limit_group_set_min_share(g, g->configured_min_share); + + UNLOCK_GROUP(g); + return 0; +} + +int +bufferevent_rate_limit_group_set_min_share( + struct bufferevent_rate_limit_group *g, + size_t share) +{ + if (share > EV_SSIZE_MAX) + return -1; + + g->configured_min_share = share; + + /* Can't set share to less than the one-tick maximum. IOW, at steady + * state, at least one connection can go per tick. */ + if (share > g->rate_limit_cfg.read_rate) + share = g->rate_limit_cfg.read_rate; + if (share > g->rate_limit_cfg.write_rate) + share = g->rate_limit_cfg.write_rate; + + g->min_share = share; + return 0; +} + +void +bufferevent_rate_limit_group_free(struct bufferevent_rate_limit_group *g) +{ + LOCK_GROUP(g); + EVUTIL_ASSERT(0 == g->n_members); + event_del(&g->master_refill_event); + UNLOCK_GROUP(g); + EVTHREAD_FREE_LOCK(g->lock, EVTHREAD_LOCKTYPE_RECURSIVE); + mm_free(g); +} + +int +bufferevent_add_to_rate_limit_group(struct bufferevent *bev, + struct bufferevent_rate_limit_group *g) +{ + int wsuspend, rsuspend; + struct bufferevent_private *bevp = + EVUTIL_UPCAST(bev, struct bufferevent_private, bev); + BEV_LOCK(bev); + + if (!bevp->rate_limiting) { + struct bufferevent_rate_limit *rlim; + rlim = mm_calloc(1, sizeof(struct bufferevent_rate_limit)); + if (!rlim) { + BEV_UNLOCK(bev); + return -1; + } + evtimer_assign(&rlim->refill_bucket_event, bev->ev_base, + _bev_refill_callback, bevp); + bevp->rate_limiting = rlim; + } + + if (bevp->rate_limiting->group == g) { + BEV_UNLOCK(bev); + return 0; + } + if (bevp->rate_limiting->group) + bufferevent_remove_from_rate_limit_group(bev); + + LOCK_GROUP(g); + bevp->rate_limiting->group = g; + ++g->n_members; + TAILQ_INSERT_TAIL(&g->members, bevp, rate_limiting->next_in_group); + + rsuspend = g->read_suspended; + wsuspend = g->write_suspended; + + UNLOCK_GROUP(g); + + if (rsuspend) + bufferevent_suspend_read(bev, BEV_SUSPEND_BW_GROUP); + if (wsuspend) + bufferevent_suspend_write(bev, BEV_SUSPEND_BW_GROUP); + + BEV_UNLOCK(bev); + return 0; +} + +int +bufferevent_remove_from_rate_limit_group(struct bufferevent *bev) +{ + return bufferevent_remove_from_rate_limit_group_internal(bev, 1); +} + +int +bufferevent_remove_from_rate_limit_group_internal(struct bufferevent *bev, + int unsuspend) +{ + struct bufferevent_private *bevp = + EVUTIL_UPCAST(bev, struct bufferevent_private, bev); + BEV_LOCK(bev); + if (bevp->rate_limiting && bevp->rate_limiting->group) { + struct bufferevent_rate_limit_group *g = + bevp->rate_limiting->group; + LOCK_GROUP(g); + bevp->rate_limiting->group = NULL; + --g->n_members; + TAILQ_REMOVE(&g->members, bevp, rate_limiting->next_in_group); + UNLOCK_GROUP(g); + } + if (unsuspend) { + bufferevent_unsuspend_read(bev, BEV_SUSPEND_BW_GROUP); + bufferevent_unsuspend_write(bev, BEV_SUSPEND_BW_GROUP); + } + BEV_UNLOCK(bev); + return 0; +} + +/* === + * API functions to expose rate limits. + * + * Don't use these from inside Libevent; they're meant to be for use by + * the program. + * === */ + +/* Mostly you don't want to use this function from inside libevent; + * _bufferevent_get_read_max() is more likely what you want*/ +ev_ssize_t +bufferevent_get_read_limit(struct bufferevent *bev) +{ + ev_ssize_t r; + struct bufferevent_private *bevp; + BEV_LOCK(bev); + bevp = BEV_UPCAST(bev); + if (bevp->rate_limiting && bevp->rate_limiting->cfg) { + bufferevent_update_buckets(bevp); + r = bevp->rate_limiting->limit.read_limit; + } else { + r = EV_SSIZE_MAX; + } + BEV_UNLOCK(bev); + return r; +} + +/* Mostly you don't want to use this function from inside libevent; + * _bufferevent_get_write_max() is more likely what you want*/ +ev_ssize_t +bufferevent_get_write_limit(struct bufferevent *bev) +{ + ev_ssize_t r; + struct bufferevent_private *bevp; + BEV_LOCK(bev); + bevp = BEV_UPCAST(bev); + if (bevp->rate_limiting && bevp->rate_limiting->cfg) { + bufferevent_update_buckets(bevp); + r = bevp->rate_limiting->limit.write_limit; + } else { + r = EV_SSIZE_MAX; + } + BEV_UNLOCK(bev); + return r; +} + +ev_ssize_t +bufferevent_get_max_to_read(struct bufferevent *bev) +{ + ev_ssize_t r; + BEV_LOCK(bev); + r = _bufferevent_get_read_max(BEV_UPCAST(bev)); + BEV_UNLOCK(bev); + return r; +} + +ev_ssize_t +bufferevent_get_max_to_write(struct bufferevent *bev) +{ + ev_ssize_t r; + BEV_LOCK(bev); + r = _bufferevent_get_write_max(BEV_UPCAST(bev)); + BEV_UNLOCK(bev); + return r; +} + + +/* Mostly you don't want to use this function from inside libevent; + * _bufferevent_get_read_max() is more likely what you want*/ +ev_ssize_t +bufferevent_rate_limit_group_get_read_limit( + struct bufferevent_rate_limit_group *grp) +{ + ev_ssize_t r; + LOCK_GROUP(grp); + r = grp->rate_limit.read_limit; + UNLOCK_GROUP(grp); + return r; +} + +/* Mostly you don't want to use this function from inside libevent; + * _bufferevent_get_write_max() is more likely what you want. */ +ev_ssize_t +bufferevent_rate_limit_group_get_write_limit( + struct bufferevent_rate_limit_group *grp) +{ + ev_ssize_t r; + LOCK_GROUP(grp); + r = grp->rate_limit.write_limit; + UNLOCK_GROUP(grp); + return r; +} + +int +bufferevent_decrement_read_limit(struct bufferevent *bev, ev_ssize_t decr) +{ + int r = 0; + ev_ssize_t old_limit, new_limit; + struct bufferevent_private *bevp; + BEV_LOCK(bev); + bevp = BEV_UPCAST(bev); + EVUTIL_ASSERT(bevp->rate_limiting && bevp->rate_limiting->cfg); + old_limit = bevp->rate_limiting->limit.read_limit; + + new_limit = (bevp->rate_limiting->limit.read_limit -= decr); + if (old_limit > 0 && new_limit <= 0) { + bufferevent_suspend_read(bev, BEV_SUSPEND_BW); + if (event_add(&bevp->rate_limiting->refill_bucket_event, + &bevp->rate_limiting->cfg->tick_timeout) < 0) + r = -1; + } else if (old_limit <= 0 && new_limit > 0) { + if (!(bevp->write_suspended & BEV_SUSPEND_BW)) + event_del(&bevp->rate_limiting->refill_bucket_event); + bufferevent_unsuspend_read(bev, BEV_SUSPEND_BW); + } + + BEV_UNLOCK(bev); + return r; +} + +int +bufferevent_decrement_write_limit(struct bufferevent *bev, ev_ssize_t decr) +{ + /* XXXX this is mostly copy-and-paste from + * bufferevent_decrement_read_limit */ + int r = 0; + ev_ssize_t old_limit, new_limit; + struct bufferevent_private *bevp; + BEV_LOCK(bev); + bevp = BEV_UPCAST(bev); + EVUTIL_ASSERT(bevp->rate_limiting && bevp->rate_limiting->cfg); + old_limit = bevp->rate_limiting->limit.write_limit; + + new_limit = (bevp->rate_limiting->limit.write_limit -= decr); + if (old_limit > 0 && new_limit <= 0) { + bufferevent_suspend_write(bev, BEV_SUSPEND_BW); + if (event_add(&bevp->rate_limiting->refill_bucket_event, + &bevp->rate_limiting->cfg->tick_timeout) < 0) + r = -1; + } else if (old_limit <= 0 && new_limit > 0) { + if (!(bevp->read_suspended & BEV_SUSPEND_BW)) + event_del(&bevp->rate_limiting->refill_bucket_event); + bufferevent_unsuspend_write(bev, BEV_SUSPEND_BW); + } + + BEV_UNLOCK(bev); + return r; +} + +int +bufferevent_rate_limit_group_decrement_read( + struct bufferevent_rate_limit_group *grp, ev_ssize_t decr) +{ + int r = 0; + ev_ssize_t old_limit, new_limit; + LOCK_GROUP(grp); + old_limit = grp->rate_limit.read_limit; + new_limit = (grp->rate_limit.read_limit -= decr); + + if (old_limit > 0 && new_limit <= 0) { + _bev_group_suspend_reading(grp); + } else if (old_limit <= 0 && new_limit > 0) { + _bev_group_unsuspend_reading(grp); + } + + UNLOCK_GROUP(grp); + return r; +} + +int +bufferevent_rate_limit_group_decrement_write( + struct bufferevent_rate_limit_group *grp, ev_ssize_t decr) +{ + int r = 0; + ev_ssize_t old_limit, new_limit; + LOCK_GROUP(grp); + old_limit = grp->rate_limit.write_limit; + new_limit = (grp->rate_limit.write_limit -= decr); + + if (old_limit > 0 && new_limit <= 0) { + _bev_group_suspend_writing(grp); + } else if (old_limit <= 0 && new_limit > 0) { + _bev_group_unsuspend_writing(grp); + } + + UNLOCK_GROUP(grp); + return r; +} + +void +bufferevent_rate_limit_group_get_totals(struct bufferevent_rate_limit_group *grp, + ev_uint64_t *total_read_out, ev_uint64_t *total_written_out) +{ + EVUTIL_ASSERT(grp != NULL); + if (total_read_out) + *total_read_out = grp->total_read; + if (total_written_out) + *total_written_out = grp->total_written; +} + +void +bufferevent_rate_limit_group_reset_totals(struct bufferevent_rate_limit_group *grp) +{ + grp->total_read = grp->total_written = 0; +} |