2 * Copyright (c) 2000-2007 Niels Provos <provos@citi.umich.edu>
3 * Copyright (c) 2007-2010 Niels Provos and Nick Mathewson
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. The name of the author may not be used to endorse or promote products
14 * derived from this software without specific prior written permission.
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 #ifndef _EVENT2_BUFFEREVENT_H_
28 #define _EVENT2_BUFFEREVENT_H_
30 /** @file bufferevent.h
32 Functions for buffering data for network sending or receiving. Bufferevents
33 are higher level than evbuffers: each has an underlying evbuffer for reading
34 and one for writing, and callbacks that are invoked under certain
37 Libevent provides an abstraction on top of the regular event callbacks.
38 This abstraction is called a buffered event. A buffered event provides
39 input and output buffers that get filled and drained automatically. The
40 user of a buffered event no longer deals directly with the I/O, but
41 instead is reading from input and writing to output buffers.
43 Once initialized, the bufferevent structure can be used repeatedly with
44 bufferevent_enable() and bufferevent_disable().
46 When read enabled the bufferevent will try to read from the file descriptor
47 and call the read callback. The write callback is executed whenever the
48 output buffer is drained below the write low watermark, which is 0 by
57 #include <event2/event-config.h>
58 #ifdef _EVENT_HAVE_SYS_TYPES_H
59 #include <sys/types.h>
61 #ifdef _EVENT_HAVE_SYS_TIME_H
66 #include <event2/util.h>
68 /* Just for error reporting - use other constants otherwise */
69 #define BEV_EVENT_READING 0x01 /**< error encountered while reading */
70 #define BEV_EVENT_WRITING 0x02 /**< error encountered while writing */
71 #define BEV_EVENT_EOF 0x10 /**< eof file reached */
72 #define BEV_EVENT_ERROR 0x20 /**< unrecoverable error encountered */
73 #define BEV_EVENT_TIMEOUT 0x40 /**< user specified timeout reached */
74 #define BEV_EVENT_CONNECTED 0x80 /**< connect operation finished. */
81 type definition for the read or write callback.
83 The read callback is triggered when new data arrives in the input
84 buffer and the amount of readable data exceed the low watermark
85 which is 0 by default.
87 The write callback is triggered if the write buffer has been
88 exhausted or fell below its low watermark.
90 @param bev the bufferevent that triggered the callback
91 @param ctx the user specified context for this bufferevent
93 typedef void (*bufferevent_data_cb)(struct bufferevent *bev, void *ctx);
96 type definition for the error callback of a bufferevent.
98 The error callback is triggered if either an EOF condition or another
99 unrecoverable error was encountered.
101 @param bev the bufferevent for which the error condition was reached
102 @param what a conjunction of flags: BEV_EVENT_READING or BEV_EVENT_WRITING
103 to indicate if the error was encountered on the read or write path,
104 and one of the following flags: BEV_EVENT_EOF, BEV_EVENT_ERROR,
105 BEV_EVENT_TIMEOUT, BEV_EVENT_CONNECTED.
107 @param ctx the user specified context for this bufferevent
109 typedef void (*bufferevent_event_cb)(struct bufferevent *bev, short what, void *ctx);
111 /** Options that can be specified when creating a bufferevent */
112 enum bufferevent_options {
113 /** If set, we close the underlying file
114 * descriptor/bufferevent/whatever when this bufferevent is freed. */
115 BEV_OPT_CLOSE_ON_FREE = (1<<0),
117 /** If set, and threading is enabled, operations on this bufferevent
118 * are protected by a lock */
119 BEV_OPT_THREADSAFE = (1<<1),
121 /** If set, callbacks are run deferred in the event loop. */
122 BEV_OPT_DEFER_CALLBACKS = (1<<2),
124 /** If set, callbacks are executed without locks being held on the
125 * bufferevent. This option currently requires that
126 * BEV_OPT_DEFER_CALLBACKS also be set; a future version of Libevent
127 * might remove the requirement.*/
128 BEV_OPT_UNLOCK_CALLBACKS = (1<<3)
132 Create a new socket bufferevent over an existing socket.
134 @param base the event base to associate with the new bufferevent.
135 @param fd the file descriptor from which data is read and written to.
136 This file descriptor is not allowed to be a pipe(2).
137 It is safe to set the fd to -1, so long as you later
138 set it with bufferevent_setfd or bufferevent_socket_connect().
139 @return a pointer to a newly allocated bufferevent struct, or NULL if an
141 @see bufferevent_free()
143 struct bufferevent *bufferevent_socket_new(struct event_base *base, evutil_socket_t fd, int options);
146 Launch a connect() attempt with a socket. When the connect succeeds,
147 the eventcb will be invoked with BEV_EVENT_CONNECTED set.
149 If the bufferevent does not already have a socket set, we allocate a new
150 socket here and make it nonblocking before we begin.
152 If no address is provided, we assume that the socket is already connecting,
153 and configure the bufferevent so that a BEV_EVENT_CONNECTED event will be
154 yielded when it is done connecting.
156 @param bufev an existing bufferevent allocated with
157 bufferevent_socket_new().
158 @param addr the address we should connect to
159 @param socklen The length of the address
160 @return 0 on success, -1 on failure.
162 int bufferevent_socket_connect(struct bufferevent *, struct sockaddr *, int);
166 Resolve the hostname 'hostname' and connect to it as with
167 bufferevent_socket_connect().
169 @param bufev An existing bufferevent allocated with bufferevent_socket_new()
170 @param evdns_base Optionally, an evdns_base to use for resolving hostnames
171 asynchronously. May be set to NULL for a blocking resolve.
172 @param family A preferred address family to resolve addresses to, or
173 AF_UNSPEC for no preference. Only AF_INET, AF_INET6, and AF_UNSPEC are
175 @param hostname The hostname to resolve; see below for notes on recognized
177 @param port The port to connect to on the resolved address.
178 @return 0 if successful, -1 on failure.
180 Recognized hostname formats are:
182 www.example.com (hostname)
183 1.2.3.4 (ipv4address)
185 [::1] ([ipv6address])
187 Performance note: If you do not provide an evdns_base, this function
188 may block while it waits for a DNS response. This is probably not
191 int bufferevent_socket_connect_hostname(struct bufferevent *b,
192 struct evdns_base *, int, const char *, int);
195 Return the error code for the last failed DNS lookup attempt made by
196 bufferevent_socket_connect_hostname().
198 @param bev The bufferevent object.
199 @return DNS error code.
200 @see evutil_gai_strerror()
202 int bufferevent_socket_get_dns_error(struct bufferevent *bev);
205 Assign a bufferevent to a specific event_base.
207 NOTE that only socket bufferevents support this function.
209 @param base an event_base returned by event_init()
210 @param bufev a bufferevent struct returned by bufferevent_new()
211 or bufferevent_socket_new()
212 @return 0 if successful, or -1 if an error occurred
213 @see bufferevent_new()
215 int bufferevent_base_set(struct event_base *base, struct bufferevent *bufev);
218 Return the event_base used by a bufferevent
220 struct event_base *bufferevent_get_base(struct bufferevent *bev);
223 Assign a priority to a bufferevent.
225 Only supported for socket bufferevents.
227 @param bufev a bufferevent struct
228 @param pri the priority to be assigned
229 @return 0 if successful, or -1 if an error occurred
231 int bufferevent_priority_set(struct bufferevent *bufev, int pri);
235 Deallocate the storage associated with a bufferevent structure.
237 @param bufev the bufferevent structure to be freed.
239 void bufferevent_free(struct bufferevent *bufev);
243 Changes the callbacks for a bufferevent.
245 @param bufev the bufferevent object for which to change callbacks
246 @param readcb callback to invoke when there is data to be read, or NULL if
247 no callback is desired
248 @param writecb callback to invoke when the file descriptor is ready for
249 writing, or NULL if no callback is desired
250 @param eventcb callback to invoke when there is an event on the file
252 @param cbarg an argument that will be supplied to each of the callbacks
253 (readcb, writecb, and errorcb)
254 @see bufferevent_new()
256 void bufferevent_setcb(struct bufferevent *bufev,
257 bufferevent_data_cb readcb, bufferevent_data_cb writecb,
258 bufferevent_event_cb eventcb, void *cbarg);
261 Changes the file descriptor on which the bufferevent operates.
262 Not supported for all bufferevent types.
264 @param bufev the bufferevent object for which to change the file descriptor
265 @param fd the file descriptor to operate on
267 int bufferevent_setfd(struct bufferevent *bufev, evutil_socket_t fd);
270 Returns the file descriptor associated with a bufferevent, or -1 if
271 no file descriptor is associated with the bufferevent.
273 evutil_socket_t bufferevent_getfd(struct bufferevent *bufev);
276 Returns the underlying bufferevent associated with a bufferevent (if
277 the bufferevent is a wrapper), or NULL if there is no underlying bufferevent.
279 struct bufferevent *bufferevent_get_underlying(struct bufferevent *bufev);
282 Write data to a bufferevent buffer.
284 The bufferevent_write() function can be used to write data to the file
285 descriptor. The data is appended to the output buffer and written to the
286 descriptor automatically as it becomes available for writing.
288 @param bufev the bufferevent to be written to
289 @param data a pointer to the data to be written
290 @param size the length of the data, in bytes
291 @return 0 if successful, or -1 if an error occurred
292 @see bufferevent_write_buffer()
294 int bufferevent_write(struct bufferevent *bufev,
295 const void *data, size_t size);
299 Write data from an evbuffer to a bufferevent buffer. The evbuffer is
300 being drained as a result.
302 @param bufev the bufferevent to be written to
303 @param buf the evbuffer to be written
304 @return 0 if successful, or -1 if an error occurred
305 @see bufferevent_write()
307 int bufferevent_write_buffer(struct bufferevent *bufev, struct evbuffer *buf);
311 Read data from a bufferevent buffer.
313 The bufferevent_read() function is used to read data from the input buffer.
315 @param bufev the bufferevent to be read from
316 @param data pointer to a buffer that will store the data
317 @param size the size of the data buffer, in bytes
318 @return the amount of data read, in bytes.
320 size_t bufferevent_read(struct bufferevent *bufev, void *data, size_t size);
323 Read data from a bufferevent buffer into an evbuffer. This avoids
326 @param bufev the bufferevent to be read from
327 @param buf the evbuffer to which to add data
328 @return 0 if successful, or -1 if an error occurred.
330 int bufferevent_read_buffer(struct bufferevent *bufev, struct evbuffer *buf);
333 Returns the input buffer.
335 The user MUST NOT set the callback on this buffer.
337 @param bufev the bufferevent from which to get the evbuffer
338 @return the evbuffer object for the input buffer
341 struct evbuffer *bufferevent_get_input(struct bufferevent *bufev);
344 Returns the output buffer.
346 The user MUST NOT set the callback on this buffer.
348 When filters are being used, the filters need to be manually
349 triggered if the output buffer was manipulated.
351 @param bufev the bufferevent from which to get the evbuffer
352 @return the evbuffer object for the output buffer
355 struct evbuffer *bufferevent_get_output(struct bufferevent *bufev);
358 Enable a bufferevent.
360 @param bufev the bufferevent to be enabled
361 @param event any combination of EV_READ | EV_WRITE.
362 @return 0 if successful, or -1 if an error occurred
363 @see bufferevent_disable()
365 int bufferevent_enable(struct bufferevent *bufev, short event);
368 Disable a bufferevent.
370 @param bufev the bufferevent to be disabled
371 @param event any combination of EV_READ | EV_WRITE.
372 @return 0 if successful, or -1 if an error occurred
373 @see bufferevent_enable()
375 int bufferevent_disable(struct bufferevent *bufev, short event);
378 Return the events that are enabled on a given bufferevent.
380 @param bufev the bufferevent to inspect
381 @return A combination of EV_READ | EV_WRITE
383 short bufferevent_get_enabled(struct bufferevent *bufev);
386 Set the read and write timeout for a buffered event.
388 A bufferevent's timeout will fire the first time that the indicated
389 amount of time has elapsed since a successful read or write operation,
390 during which the bufferevent was trying to read or write.
392 (In other words, if reading or writing is disabled, or if the
393 bufferevent's read or write operation has been suspended because
394 there's no data to write, or not enough banwidth, or so on, the
395 timeout isn't active. The timeout only becomes active when we we're
396 willing to actually read or write.)
398 Calling bufferevent_enable or setting a timeout for a bufferevent
399 whose timeout is already pending resets its timeout.
401 If the timeout elapses, the corresponding operation (EV_READ or
402 EV_WRITE) becomes disabled until you re-enable it again. The
403 bufferevent's event callback is called with the
404 BEV_EVENT_TIMEOUT|BEV_EVENT_READING or
405 BEV_EVENT_TIMEOUT|BEV_EVENT_WRITING.
407 @param bufev the bufferevent to be modified
408 @param timeout_read the read timeout, or NULL
409 @param timeout_write the write timeout, or NULL
411 int bufferevent_set_timeouts(struct bufferevent *bufev,
412 const struct timeval *timeout_read, const struct timeval *timeout_write);
415 Sets the watermarks for read and write events.
417 On input, a bufferevent does not invoke the user read callback unless
418 there is at least low watermark data in the buffer. If the read buffer
419 is beyond the high watermark, the bufferevent stops reading from the network.
421 On output, the user write callback is invoked whenever the buffered data
422 falls below the low watermark. Filters that write to this bufev will try
423 not to write more bytes to this buffer than the high watermark would allow,
424 except when flushing.
426 @param bufev the bufferevent to be modified
427 @param events EV_READ, EV_WRITE or both
428 @param lowmark the lower watermark to set
429 @param highmark the high watermark to set
432 void bufferevent_setwatermark(struct bufferevent *bufev, short events,
433 size_t lowmark, size_t highmark);
436 Acquire the lock on a bufferevent. Has no effect if locking was not
437 enabled with BEV_OPT_THREADSAFE.
439 void bufferevent_lock(struct bufferevent *bufev);
442 Release the lock on a bufferevent. Has no effect if locking was not
443 enabled with BEV_OPT_THREADSAFE.
445 void bufferevent_unlock(struct bufferevent *bufev);
448 Flags that can be passed into filters to let them know how to
449 deal with the incoming data.
451 enum bufferevent_flush_mode {
452 /** usually set when processing data */
455 /** want to checkpoint all data sent. */
458 /** encountered EOF on read or done sending data */
463 Triggers the bufferevent to produce more
466 @param bufev the bufferevent object
467 @param iotype either EV_READ or EV_WRITE or both.
468 @param mode either BEV_NORMAL or BEV_FLUSH or BEV_FINISHED
469 @return -1 on failure, 0 if no data was produces, 1 if data was produced
471 int bufferevent_flush(struct bufferevent *bufev,
473 enum bufferevent_flush_mode mode);
476 Support for filtering input and output of bufferevents.
480 Values that filters can return.
482 enum bufferevent_filter_result {
483 /** everything is okay */
486 /** the filter needs to read more data before output */
489 /** the filter encountered a critical error, no further data
494 /** A callback function to implement a filter for a bufferevent.
496 @param src An evbuffer to drain data from.
497 @param dst An evbuffer to add data to.
498 @param limit A suggested upper bound of bytes to write to dst.
499 The filter may ignore this value, but doing so means that
500 it will overflow the high-water mark associated with dst.
502 @param mode Whether we should write data as may be convenient
503 (BEV_NORMAL), or flush as much data as we can (BEV_FLUSH),
504 or flush as much as we can, possibly including an end-of-stream
506 @param ctx A user-supplied pointer.
508 @return BEV_OK if we wrote some data; BEV_NEED_MORE if we can't
509 produce any more output until we get some input; and BEV_ERROR
512 typedef enum bufferevent_filter_result (*bufferevent_filter_cb)(
513 struct evbuffer *src, struct evbuffer *dst, ev_ssize_t dst_limit,
514 enum bufferevent_flush_mode mode, void *ctx);
517 Allocate a new filtering bufferevent on top of an existing bufferevent.
519 @param underlying the underlying bufferevent.
520 @param input_filter The filter to apply to data we read from the underlying
522 @param output_filter The filer to apply to data we write to the underlying
524 @param options A bitfield of bufferevent options.
525 @param free_context A function to use to free the filter context when
526 this bufferevent is freed.
527 @param ctx A context pointer to pass to the filter functions.
530 bufferevent_filter_new(struct bufferevent *underlying,
531 bufferevent_filter_cb input_filter,
532 bufferevent_filter_cb output_filter,
534 void (*free_context)(void *),
538 Allocate a pair of linked bufferevents. The bufferevents behave as would
539 two bufferevent_sock instances connected to opposite ends of a
540 socketpair(), except that no internal socketpair is allocated.
542 @param base The event base to associate with the socketpair.
543 @param options A set of options for this bufferevent
544 @param pair A pointer to an array to hold the two new bufferevent objects.
545 @return 0 on success, -1 on failure.
547 int bufferevent_pair_new(struct event_base *base, int options,
548 struct bufferevent *pair[2]);
551 Given one bufferevent returned by bufferevent_pair_new(), returns the
552 other one if it still exists. Otherwise returns NULL.
554 struct bufferevent *bufferevent_pair_get_partner(struct bufferevent *bev);
557 Abstract type used to configure rate-limiting on a bufferevent or a group
560 struct ev_token_bucket_cfg;
563 A group of bufferevents which are configured to respect the same rate
566 struct bufferevent_rate_limit_group;
568 /** Maximum configurable rate- or burst-limit. */
569 #define EV_RATE_LIMIT_MAX EV_SSIZE_MAX
572 Initialize and return a new object to configure the rate-limiting behavior
575 @param read_rate The maximum number of bytes to read per tick on
577 @param read_burst The maximum number of bytes to read in any single tick.
578 @param write_rate The maximum number of bytes to write per tick on
580 @param write_burst The maximum number of bytes to write in any single tick.
581 @param tick_len The length of a single tick. Defaults to one second.
582 Any fractions of a millisecond are ignored.
584 Note that all rate-limits hare are currently best-effort: future versions
585 of Libevent may implement them more tightly.
587 struct ev_token_bucket_cfg *ev_token_bucket_cfg_new(
588 size_t read_rate, size_t read_burst,
589 size_t write_rate, size_t write_burst,
590 const struct timeval *tick_len);
592 /** Free all storage held in 'cfg'.
594 Note: 'cfg' is not currently reference-counted; it is not safe to free it
595 until no bufferevent is using it.
597 void ev_token_bucket_cfg_free(struct ev_token_bucket_cfg *cfg);
600 Set the rate-limit of a the bufferevent 'bev' to the one specified in
601 'cfg'. If 'cfg' is NULL, disable any per-bufferevent rate-limiting on
604 Note that only some bufferevent types currently respect rate-limiting.
605 They are: socket-based bufferevents (normal and IOCP-based), and SSL-based
608 Return 0 on sucess, -1 on failure.
610 int bufferevent_set_rate_limit(struct bufferevent *bev,
611 struct ev_token_bucket_cfg *cfg);
614 Create a new rate-limit group for bufferevents. A rate-limit group
615 constrains the maximum number of bytes sent and received, in toto,
616 by all of its bufferevents.
618 @param base An event_base to run any necessary timeouts for the group.
619 Note that all bufferevents in the group do not necessarily need to share
621 @param cfg The rate-limit for this group.
623 Note that all rate-limits hare are currently best-effort: future versions
624 of Libevent may implement them more tightly.
626 Note also that only some bufferevent types currently respect rate-limiting.
627 They are: socket-based bufferevents (normal and IOCP-based), and SSL-based
630 struct bufferevent_rate_limit_group *bufferevent_rate_limit_group_new(
631 struct event_base *base,
632 const struct ev_token_bucket_cfg *cfg);
634 Change the rate-limiting settings for a given rate-limiting group.
636 Return 0 on success, -1 on failure.
638 int bufferevent_rate_limit_group_set_cfg(
639 struct bufferevent_rate_limit_group *,
640 const struct ev_token_bucket_cfg *);
643 Change the smallest quantum we're willing to allocate to any single
644 bufferevent in a group for reading or writing at a time.
646 The rationale is that, because of TCP/IP protocol overheads and kernel
647 behavior, if a rate-limiting group is so tight on bandwidth that you're
648 only willing to send 1 byte per tick per bufferevent, you might instead
649 want to batch up the reads and writes so that you send N bytes per
650 1/N of the bufferevents (chosen at random) each tick, so you still wind
651 up send 1 byte per tick per bufferevent on average, but you don't send
652 so many tiny packets.
654 The default min-share is currently 64 bytes.
656 Returns 0 on success, -1 on faulre.
658 int bufferevent_rate_limit_group_set_min_share(
659 struct bufferevent_rate_limit_group *, size_t);
662 Free a rate-limiting group. The group must have no members when
663 this function is called.
665 void bufferevent_rate_limit_group_free(struct bufferevent_rate_limit_group *);
668 Add 'bev' to the list of bufferevents whose aggregate reading and writing
669 is restricted by 'g'. If 'g' is NULL, remove 'bev' from its current group.
671 A bufferevent may belong to no more than one rate-limit group at a time.
672 If 'bev' is already a member of a group, it will be removed from its old
673 group before being added to 'g'.
675 Return 0 on success and -1 on failure.
677 int bufferevent_add_to_rate_limit_group(struct bufferevent *bev,
678 struct bufferevent_rate_limit_group *g);
680 /** Remove 'bev' from its current rate-limit group (if any). */
681 int bufferevent_remove_from_rate_limit_group(struct bufferevent *bev);
685 Return the current read or write bucket size for a bufferevent.
686 If it is not configured with a per-bufferevent ratelimit, return
687 EV_SSIZE_MAX. This function does not inspect the group limit, if any.
688 Note that it can return a negative value if the bufferevent has been
689 made to read or write more than its limit.
691 ev_ssize_t bufferevent_get_read_limit(struct bufferevent *bev);
692 ev_ssize_t bufferevent_get_write_limit(struct bufferevent *bev);
695 ev_ssize_t bufferevent_get_max_to_read(struct bufferevent *bev);
696 ev_ssize_t bufferevent_get_max_to_write(struct bufferevent *bev);
700 Return the read or write bucket size for a bufferevent rate limit
701 group. Note that it can return a negative value if bufferevents in
702 the group have been made to read or write more than their limits.
704 ev_ssize_t bufferevent_rate_limit_group_get_read_limit(
705 struct bufferevent_rate_limit_group *);
706 ev_ssize_t bufferevent_rate_limit_group_get_write_limit(
707 struct bufferevent_rate_limit_group *);
712 Subtract a number of bytes from a bufferevent's read or write bucket.
713 The decrement value can be negative, if you want to manually refill
714 the bucket. If the change puts the bucket above or below zero, the
715 bufferevent will resume or suspend reading writing as appropriate.
716 These functions make no change in the buckets for the bufferevent's
719 Returns 0 on success, -1 on internal error.
721 int bufferevent_decrement_read_limit(struct bufferevent *bev, ev_ssize_t decr);
722 int bufferevent_decrement_write_limit(struct bufferevent *bev, ev_ssize_t decr);
727 Subtract a number of bytes from a bufferevent rate-limiting group's
728 read or write bucket. The decrement value can be negative, if you
729 want to manually refill the bucket. If the change puts the bucket
730 above or below zero, the bufferevents in the group will resume or
731 suspend reading writing as appropriate.
733 Returns 0 on success, -1 on internal error.
735 int bufferevent_rate_limit_group_decrement_read(
736 struct bufferevent_rate_limit_group *, ev_ssize_t);
737 int bufferevent_rate_limit_group_decrement_write(
738 struct bufferevent_rate_limit_group *, ev_ssize_t);
742 /** Set the variable pointed to by total_read_out to the total number of bytes
743 * ever read on grp, and the variable pointed to by total_written_out to the
744 * total number of bytes ever written on grp. */
745 void bufferevent_rate_limit_group_get_totals(
746 struct bufferevent_rate_limit_group *grp,
747 ev_uint64_t *total_read_out, ev_uint64_t *total_written_out);
749 /** Reset the number of bytes read or written on grp as given by
750 * bufferevent_rate_limit_group_reset_totals(). */
752 bufferevent_rate_limit_group_reset_totals(
753 struct bufferevent_rate_limit_group *grp);
759 #endif /* _EVENT2_BUFFEREVENT_H_ */