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482 lines
18 KiB
482 lines
18 KiB
/*
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* Copyright (c) 2008-2012 Niels Provos and Nick Mathewson
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef BUFFEREVENT_INTERNAL_H_INCLUDED_
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#define BUFFEREVENT_INTERNAL_H_INCLUDED_
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#ifdef __cplusplus
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extern "C" {
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#endif
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#include "event2/event-config.h"
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#include "event2/event_struct.h"
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#include "evconfig-private.h"
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#include "event2/util.h"
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#include "defer-internal.h"
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#include "evthread-internal.h"
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#include "event2/thread.h"
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#include "ratelim-internal.h"
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#include "event2/bufferevent_struct.h"
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#include "ipv6-internal.h"
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#ifdef _WIN32
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#include <ws2tcpip.h>
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#endif
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#ifdef EVENT__HAVE_NETINET_IN_H
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#include <netinet/in.h>
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#endif
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#ifdef EVENT__HAVE_NETINET_IN6_H
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#include <netinet/in6.h>
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#endif
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/* These flags are reasons that we might be declining to actually enable
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reading or writing on a bufferevent.
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*/
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/* On a all bufferevents, for reading: used when we have read up to the
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watermark value.
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On a filtering bufferevent, for writing: used when the underlying
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bufferevent's write buffer has been filled up to its watermark
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value.
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*/
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#define BEV_SUSPEND_WM 0x01
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/* On a base bufferevent: when we have emptied a bandwidth buckets */
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#define BEV_SUSPEND_BW 0x02
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/* On a base bufferevent: when we have emptied the group's bandwidth bucket. */
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#define BEV_SUSPEND_BW_GROUP 0x04
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/* On a socket bufferevent: can't do any operations while we're waiting for
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* name lookup to finish. */
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#define BEV_SUSPEND_LOOKUP 0x08
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/* On a base bufferevent, for reading: used when a filter has choked this
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* (underlying) bufferevent because it has stopped reading from it. */
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#define BEV_SUSPEND_FILT_READ 0x10
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typedef ev_uint16_t bufferevent_suspend_flags;
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struct bufferevent_rate_limit_group {
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/** List of all members in the group */
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LIST_HEAD(rlim_group_member_list, bufferevent_private) members;
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/** Current limits for the group. */
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struct ev_token_bucket rate_limit;
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struct ev_token_bucket_cfg rate_limit_cfg;
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/** True iff we don't want to read from any member of the group.until
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* the token bucket refills. */
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unsigned read_suspended : 1;
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/** True iff we don't want to write from any member of the group.until
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* the token bucket refills. */
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unsigned write_suspended : 1;
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/** True iff we were unable to suspend one of the bufferevents in the
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* group for reading the last time we tried, and we should try
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* again. */
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unsigned pending_unsuspend_read : 1;
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/** True iff we were unable to suspend one of the bufferevents in the
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* group for writing the last time we tried, and we should try
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* again. */
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unsigned pending_unsuspend_write : 1;
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/*@{*/
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/** Total number of bytes read or written in this group since last
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* reset. */
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ev_uint64_t total_read;
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ev_uint64_t total_written;
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/*@}*/
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/** The number of bufferevents in the group. */
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int n_members;
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/** The smallest number of bytes that any member of the group should
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* be limited to read or write at a time. */
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ev_ssize_t min_share;
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ev_ssize_t configured_min_share;
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/** Timeout event that goes off once a tick, when the bucket is ready
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* to refill. */
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struct event master_refill_event;
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/** Seed for weak random number generator. Protected by 'lock' */
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struct evutil_weakrand_state weakrand_seed;
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/** Lock to protect the members of this group. This lock should nest
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* within every bufferevent lock: if you are holding this lock, do
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* not assume you can lock another bufferevent. */
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void *lock;
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};
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/** Fields for rate-limiting a single bufferevent. */
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struct bufferevent_rate_limit {
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/* Linked-list elements for storing this bufferevent_private in a
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* group.
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*
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* Note that this field is supposed to be protected by the group
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* lock */
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LIST_ENTRY(bufferevent_private) next_in_group;
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/** The rate-limiting group for this bufferevent, or NULL if it is
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* only rate-limited on its own. */
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struct bufferevent_rate_limit_group *group;
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/* This bufferevent's current limits. */
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struct ev_token_bucket limit;
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/* Pointer to the rate-limit configuration for this bufferevent.
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* Can be shared. XXX reference-count this? */
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struct ev_token_bucket_cfg *cfg;
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/* Timeout event used when one this bufferevent's buckets are
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* empty. */
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struct event refill_bucket_event;
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};
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/** Parts of the bufferevent structure that are shared among all bufferevent
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* types, but not exposed in bufferevent_struct.h. */
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struct bufferevent_private {
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/** The underlying bufferevent structure. */
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struct bufferevent bev;
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/** Evbuffer callback to enforce watermarks on input. */
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struct evbuffer_cb_entry *read_watermarks_cb;
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/** If set, we should free the lock when we free the bufferevent. */
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unsigned own_lock : 1;
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/** Flag: set if we have deferred callbacks and a read callback is
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* pending. */
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unsigned readcb_pending : 1;
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/** Flag: set if we have deferred callbacks and a write callback is
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* pending. */
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unsigned writecb_pending : 1;
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/** Flag: set if we are currently busy connecting. */
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unsigned connecting : 1;
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/** Flag: set if a connect failed prematurely; this is a hack for
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* getting around the bufferevent abstraction. */
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unsigned connection_refused : 1;
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/** Set to the events pending if we have deferred callbacks and
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* an events callback is pending. */
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short eventcb_pending;
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/** If set, read is suspended until one or more conditions are over.
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* The actual value here is a bitfield of those conditions; see the
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* BEV_SUSPEND_* flags above. */
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bufferevent_suspend_flags read_suspended;
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/** If set, writing is suspended until one or more conditions are over.
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* The actual value here is a bitfield of those conditions; see the
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* BEV_SUSPEND_* flags above. */
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bufferevent_suspend_flags write_suspended;
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/** Set to the current socket errno if we have deferred callbacks and
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* an events callback is pending. */
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int errno_pending;
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/** The DNS error code for bufferevent_socket_connect_hostname */
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int dns_error;
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/** Used to implement deferred callbacks */
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struct event_callback deferred;
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/** The options this bufferevent was constructed with */
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enum bufferevent_options options;
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/** Current reference count for this bufferevent. */
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int refcnt;
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/** Lock for this bufferevent. Shared by the inbuf and the outbuf.
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* If NULL, locking is disabled. */
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void *lock;
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/** No matter how big our bucket gets, don't try to read more than this
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* much in a single read operation. */
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ev_ssize_t max_single_read;
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/** No matter how big our bucket gets, don't try to write more than this
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* much in a single write operation. */
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ev_ssize_t max_single_write;
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/** Rate-limiting information for this bufferevent */
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struct bufferevent_rate_limit *rate_limiting;
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/* Saved conn_addr, to extract IP address from it.
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*
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* Because some servers may reset/close connection without waiting clients,
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* in that case we can't extract IP address even in close_cb.
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* So we need to save it, just after we connected to remote server, or
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* after resolving (to avoid extra dns requests during retrying, since UDP
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* is slow) */
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union {
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struct sockaddr_in6 in6;
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struct sockaddr_in in;
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} conn_address;
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struct evdns_getaddrinfo_request *dns_request;
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};
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/** Possible operations for a control callback. */
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enum bufferevent_ctrl_op {
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BEV_CTRL_SET_FD,
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BEV_CTRL_GET_FD,
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BEV_CTRL_GET_UNDERLYING,
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BEV_CTRL_CANCEL_ALL
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};
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/** Possible data types for a control callback */
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union bufferevent_ctrl_data {
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void *ptr;
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evutil_socket_t fd;
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};
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/**
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Implementation table for a bufferevent: holds function pointers and other
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information to make the various bufferevent types work.
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*/
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struct bufferevent_ops {
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/** The name of the bufferevent's type. */
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const char *type;
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/** At what offset into the implementation type will we find a
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bufferevent structure?
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Example: if the type is implemented as
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struct bufferevent_x {
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int extra_data;
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struct bufferevent bev;
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}
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then mem_offset should be offsetof(struct bufferevent_x, bev)
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*/
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off_t mem_offset;
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/** Enables one or more of EV_READ|EV_WRITE on a bufferevent. Does
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not need to adjust the 'enabled' field. Returns 0 on success, -1
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on failure.
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*/
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int (*enable)(struct bufferevent *, short);
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/** Disables one or more of EV_READ|EV_WRITE on a bufferevent. Does
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not need to adjust the 'enabled' field. Returns 0 on success, -1
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on failure.
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*/
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int (*disable)(struct bufferevent *, short);
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/** Detatches the bufferevent from related data structures. Called as
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* soon as its reference count reaches 0. */
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void (*unlink)(struct bufferevent *);
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/** Free any storage and deallocate any extra data or structures used
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in this implementation. Called when the bufferevent is
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finalized.
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*/
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void (*destruct)(struct bufferevent *);
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/** Called when the timeouts on the bufferevent have changed.*/
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int (*adj_timeouts)(struct bufferevent *);
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/** Called to flush data. */
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int (*flush)(struct bufferevent *, short, enum bufferevent_flush_mode);
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/** Called to access miscellaneous fields. */
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int (*ctrl)(struct bufferevent *, enum bufferevent_ctrl_op, union bufferevent_ctrl_data *);
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};
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extern const struct bufferevent_ops bufferevent_ops_socket;
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extern const struct bufferevent_ops bufferevent_ops_filter;
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extern const struct bufferevent_ops bufferevent_ops_pair;
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#define BEV_IS_SOCKET(bevp) ((bevp)->be_ops == &bufferevent_ops_socket)
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#define BEV_IS_FILTER(bevp) ((bevp)->be_ops == &bufferevent_ops_filter)
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#define BEV_IS_PAIR(bevp) ((bevp)->be_ops == &bufferevent_ops_pair)
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#ifdef _WIN32
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extern const struct bufferevent_ops bufferevent_ops_async;
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#define BEV_IS_ASYNC(bevp) ((bevp)->be_ops == &bufferevent_ops_async)
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#else
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#define BEV_IS_ASYNC(bevp) 0
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#endif
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/** Initialize the shared parts of a bufferevent. */
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int bufferevent_init_common_(struct bufferevent_private *, struct event_base *, const struct bufferevent_ops *, enum bufferevent_options options);
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/** For internal use: temporarily stop all reads on bufev, until the conditions
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* in 'what' are over. */
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void bufferevent_suspend_read_(struct bufferevent *bufev, bufferevent_suspend_flags what);
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/** For internal use: clear the conditions 'what' on bufev, and re-enable
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* reading if there are no conditions left. */
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void bufferevent_unsuspend_read_(struct bufferevent *bufev, bufferevent_suspend_flags what);
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/** For internal use: temporarily stop all writes on bufev, until the conditions
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* in 'what' are over. */
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void bufferevent_suspend_write_(struct bufferevent *bufev, bufferevent_suspend_flags what);
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/** For internal use: clear the conditions 'what' on bufev, and re-enable
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* writing if there are no conditions left. */
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void bufferevent_unsuspend_write_(struct bufferevent *bufev, bufferevent_suspend_flags what);
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#define bufferevent_wm_suspend_read(b) \
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bufferevent_suspend_read_((b), BEV_SUSPEND_WM)
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#define bufferevent_wm_unsuspend_read(b) \
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bufferevent_unsuspend_read_((b), BEV_SUSPEND_WM)
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/*
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Disable a bufferevent. Equivalent to bufferevent_disable(), but
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first resets 'connecting' flag to force EV_WRITE down for sure.
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XXXX this method will go away in the future; try not to add new users.
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See comment in evhttp_connection_reset_() for discussion.
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@param bufev the bufferevent to be disabled
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@param event any combination of EV_READ | EV_WRITE.
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@return 0 if successful, or -1 if an error occurred
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@see bufferevent_disable()
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*/
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int bufferevent_disable_hard_(struct bufferevent *bufev, short event);
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/** Internal: Set up locking on a bufferevent. If lock is set, use it.
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* Otherwise, use a new lock. */
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int bufferevent_enable_locking_(struct bufferevent *bufev, void *lock);
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/** Internal: backwards compat macro for the now public function
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* Increment the reference count on bufev. */
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#define bufferevent_incref_(bufev) bufferevent_incref(bufev)
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/** Internal: Lock bufev and increase its reference count.
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* unlocking it otherwise. */
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void bufferevent_incref_and_lock_(struct bufferevent *bufev);
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/** Internal: backwards compat macro for the now public function
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* Decrement the reference count on bufev. Returns 1 if it freed
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* the bufferevent.*/
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#define bufferevent_decref_(bufev) bufferevent_decref(bufev)
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/** Internal: Drop the reference count on bufev, freeing as necessary, and
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* unlocking it otherwise. Returns 1 if it freed the bufferevent. */
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int bufferevent_decref_and_unlock_(struct bufferevent *bufev);
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/** Internal: If callbacks are deferred and we have a read callback, schedule
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* a readcb. Otherwise just run the readcb. Ignores watermarks. */
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void bufferevent_run_readcb_(struct bufferevent *bufev, int options);
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/** Internal: If callbacks are deferred and we have a write callback, schedule
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* a writecb. Otherwise just run the writecb. Ignores watermarks. */
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void bufferevent_run_writecb_(struct bufferevent *bufev, int options);
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/** Internal: If callbacks are deferred and we have an eventcb, schedule
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* it to run with events "what". Otherwise just run the eventcb.
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* See bufferevent_trigger_event for meaning of "options". */
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void bufferevent_run_eventcb_(struct bufferevent *bufev, short what, int options);
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/** Internal: Run or schedule (if deferred or options contain
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* BEV_TRIG_DEFER_CALLBACKS) I/O callbacks specified in iotype.
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* Must already hold the bufev lock. Honors watermarks unless
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* BEV_TRIG_IGNORE_WATERMARKS is in options. */
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static inline void bufferevent_trigger_nolock_(struct bufferevent *bufev, short iotype, int options);
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/* Making this inline since all of the common-case calls to this function in
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* libevent use constant arguments. */
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static inline void
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bufferevent_trigger_nolock_(struct bufferevent *bufev, short iotype, int options)
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{
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if ((iotype & EV_READ) && ((options & BEV_TRIG_IGNORE_WATERMARKS) ||
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evbuffer_get_length(bufev->input) >= bufev->wm_read.low))
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bufferevent_run_readcb_(bufev, options);
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if ((iotype & EV_WRITE) && ((options & BEV_TRIG_IGNORE_WATERMARKS) ||
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evbuffer_get_length(bufev->output) <= bufev->wm_write.low))
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bufferevent_run_writecb_(bufev, options);
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}
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/** Internal: Add the event 'ev' with timeout tv, unless tv is set to 0, in
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* which case add ev with no timeout. */
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int bufferevent_add_event_(struct event *ev, const struct timeval *tv);
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/* =========
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* These next functions implement timeouts for bufferevents that aren't doing
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* anything else with ev_read and ev_write, to handle timeouts.
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* ========= */
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/** Internal use: Set up the ev_read and ev_write callbacks so that
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* the other "generic_timeout" functions will work on it. Call this from
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* the constructor function. */
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void bufferevent_init_generic_timeout_cbs_(struct bufferevent *bev);
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/** Internal use: Add or delete the generic timeout events as appropriate.
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* (If an event is enabled and a timeout is set, we add the event. Otherwise
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* we delete it.) Call this from anything that changes the timeout values,
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* that enabled EV_READ or EV_WRITE, or that disables EV_READ or EV_WRITE. */
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int bufferevent_generic_adj_timeouts_(struct bufferevent *bev);
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int bufferevent_generic_adj_existing_timeouts_(struct bufferevent *bev);
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enum bufferevent_options bufferevent_get_options_(struct bufferevent *bev);
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const struct sockaddr*
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bufferevent_socket_get_conn_address_(struct bufferevent *bev);
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/** Internal use: We have just successfully read data into an inbuf, so
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* reset the read timeout (if any). */
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#define BEV_RESET_GENERIC_READ_TIMEOUT(bev) \
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do { \
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if (evutil_timerisset(&(bev)->timeout_read)) \
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event_add(&(bev)->ev_read, &(bev)->timeout_read); \
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} while (0)
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/** Internal use: We have just successfully written data from an inbuf, so
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* reset the read timeout (if any). */
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#define BEV_RESET_GENERIC_WRITE_TIMEOUT(bev) \
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do { \
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if (evutil_timerisset(&(bev)->timeout_write)) \
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event_add(&(bev)->ev_write, &(bev)->timeout_write); \
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} while (0)
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#define BEV_DEL_GENERIC_READ_TIMEOUT(bev) \
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event_del(&(bev)->ev_read)
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#define BEV_DEL_GENERIC_WRITE_TIMEOUT(bev) \
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event_del(&(bev)->ev_write)
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/** Internal: Given a bufferevent, return its corresponding
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* bufferevent_private. */
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#define BEV_UPCAST(b) EVUTIL_UPCAST((b), struct bufferevent_private, bev)
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#ifdef EVENT__DISABLE_THREAD_SUPPORT
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#define BEV_LOCK(b) EVUTIL_NIL_STMT_
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#define BEV_UNLOCK(b) EVUTIL_NIL_STMT_
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#else
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/** Internal: Grab the lock (if any) on a bufferevent */
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#define BEV_LOCK(b) do { \
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struct bufferevent_private *locking = BEV_UPCAST(b); \
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EVLOCK_LOCK(locking->lock, 0); \
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} while (0)
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/** Internal: Release the lock (if any) on a bufferevent */
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#define BEV_UNLOCK(b) do { \
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struct bufferevent_private *locking = BEV_UPCAST(b); \
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EVLOCK_UNLOCK(locking->lock, 0); \
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} while (0)
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#endif
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/* ==== For rate-limiting. */
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int bufferevent_decrement_write_buckets_(struct bufferevent_private *bev,
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ev_ssize_t bytes);
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int bufferevent_decrement_read_buckets_(struct bufferevent_private *bev,
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ev_ssize_t bytes);
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ev_ssize_t bufferevent_get_read_max_(struct bufferevent_private *bev);
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ev_ssize_t bufferevent_get_write_max_(struct bufferevent_private *bev);
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|
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int bufferevent_ratelim_init_(struct bufferevent_private *bev);
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|
|
|
#ifdef __cplusplus
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|
}
|
|
#endif
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|
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#endif /* BUFFEREVENT_INTERNAL_H_INCLUDED_ */
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