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f9134df7d0
Libevent introduced the LEV_OPT_BIND_IPV6ONLY to pass to evconnlistener_new_bind to make it automatically set the underlying socket as accepting ipv6 requests. This works fine on posix compliant platforms as by the standard every new AF_INET6 socket is created as both supporting ipv6 and ipv4 connections. But on windows the default is the opposite, with the flag IPV6_V6ONLY being always enabled by default. This makes creating a listener to supports both protocols a bit more tricky as winsock doesn't allow changing this flag after evconnlistener_new_bind does all the initial setup because as stated in the docs, you can't change it after the sonnect connected, so one would have to manually create the socket beforehand and set the flag and then call evconnlistener_new with the socket itself. It would be nice to have libevent keep a consistent behaviour across the platforms in this scenario, maybe or by making it always set IPV6_V6ONLY to false unless LEV_OPT_BIND_IPV6ONLY is passed, in which case it's set to true, or add another flag to forcefully set it to false and keep the system dependent behaviour as default. So this patch add new option for libevent listeners to bind to both - LEV_OPT_BIND_IPV4_AND_IPV6
203 lines
8.2 KiB
C
203 lines
8.2 KiB
C
/*
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* Copyright (c) 2000-2007 Niels Provos <provos@citi.umich.edu>
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* Copyright (c) 2007-2012 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 EVENT2_LISTENER_H_INCLUDED_
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#define EVENT2_LISTENER_H_INCLUDED_
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#include <event2/visibility.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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#include <event2/event.h>
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struct sockaddr;
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struct evconnlistener;
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/**@file event2/listener.h
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@brief A callback that we invoke when a listener has a new connection.
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@param listener The evconnlistener
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@param fd The new file descriptor
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@param addr The source address of the connection
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@param socklen The length of addr
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@param user_arg the pointer passed to evconnlistener_new()
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*/
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typedef void (*evconnlistener_cb)(struct evconnlistener *, evutil_socket_t, struct sockaddr *, int socklen, void *);
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/**
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A callback that we invoke when a listener encounters a non-retriable error.
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@param listener The evconnlistener
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@param user_arg the pointer passed to evconnlistener_new()
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*/
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typedef void (*evconnlistener_errorcb)(struct evconnlistener *, void *);
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/** Flag: Indicates that we should not make incoming sockets nonblocking
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* before passing them to the callback. */
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#define LEV_OPT_LEAVE_SOCKETS_BLOCKING (1u<<0)
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/** Flag: Indicates that freeing the listener should close the underlying
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* socket. */
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#define LEV_OPT_CLOSE_ON_FREE (1u<<1)
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/** Flag: Indicates that we should set the close-on-exec flag, if possible */
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#define LEV_OPT_CLOSE_ON_EXEC (1u<<2)
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/** Flag: Indicates that we should disable the timeout (if any) between when
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* this socket is closed and when we can listen again on the same port. */
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#define LEV_OPT_REUSEABLE (1u<<3)
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/** Flag: Indicates that the listener should be locked so it's safe to use
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* from multiple threadcs at once. */
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#define LEV_OPT_THREADSAFE (1u<<4)
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/** Flag: Indicates that the listener should be created in disabled
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* state. Use evconnlistener_enable() to enable it later. */
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#define LEV_OPT_DISABLED (1u<<5)
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/** Flag: Indicates that the listener should defer accept() until data is
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* available, if possible. Ignored on platforms that do not support this.
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*
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* This option can help performance for protocols where the client transmits
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* immediately after connecting. Do not use this option if your protocol
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* _doesn't_ start out with the client transmitting data, since in that case
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* this option will sometimes cause the kernel to never tell you about the
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* connection.
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*
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* This option is only supported by evconnlistener_new_bind(): it can't
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* work with evconnlistener_new_fd(), since the listener needs to be told
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* to use the option before it is actually bound.
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*/
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#define LEV_OPT_DEFERRED_ACCEPT (1u<<6)
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/** Flag: Indicates that we ask to allow multiple servers (processes or
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* threads) to bind to the same port if they each set the option.
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*
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* SO_REUSEPORT is what most people would expect SO_REUSEADDR to be, however
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* SO_REUSEPORT does not imply SO_REUSEADDR.
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*
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* This is only available on Linux and kernel 3.9+
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*/
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#define LEV_OPT_REUSEABLE_PORT (1u<<7)
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/** Flag: Indicates that the listener wants to work only in IPv6 socket.
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*
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* According to RFC3493 and most Linux distributions, default value is to
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* work in IPv4-mapped mode. If there is a requirement to bind same port
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* on same ip addresses but different handlers for both IPv4 and IPv6,
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* it is required to set IPV6_V6ONLY socket option to be sure that the
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* code works as expected without affected by bindv6only sysctl setting in
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* system.
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*
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* This socket option on Windows is instead enabled by default.
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*/
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#define LEV_OPT_BIND_IPV6ONLY (1u<<8)
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/** Flag: Indicates that the listener wants to work only in both IPv4 and
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* IPv6 socket.
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*
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* This flag exists as copmlement to LEV_OPT_BIND_IPV6ONLY to account for
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* the different default behaviour on Windows so that the code can
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* explicitly request the socket to support both modes without having
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* to rely on the default option.
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*/
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#define LEV_OPT_BIND_IPV4_AND_IPV6 (1u<<9)
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/**
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Allocate a new evconnlistener object to listen for incoming TCP connections
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on a given file descriptor.
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@param base The event base to associate the listener with.
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@param cb A callback to be invoked when a new connection arrives. If the
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callback is NULL, the listener will be treated as disabled until the
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callback is set.
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@param ptr A user-supplied pointer to give to the callback.
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@param flags Any number of LEV_OPT_* flags
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@param backlog Passed to the listen() call to determine the length of the
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acceptable connection backlog. Set to -1 for a reasonable default.
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Set to 0 if the socket is already listening.
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@param fd The file descriptor to listen on. It must be a nonblocking
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file descriptor, and it should already be bound to an appropriate
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port and address.
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*/
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EVENT2_EXPORT_SYMBOL
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struct evconnlistener *evconnlistener_new(struct event_base *base,
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evconnlistener_cb cb, void *ptr, unsigned flags, int backlog,
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evutil_socket_t fd);
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/**
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Allocate a new evconnlistener object to listen for incoming TCP connections
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on a given address.
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@param base The event base to associate the listener with.
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@param cb A callback to be invoked when a new connection arrives. If the
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callback is NULL, the listener will be treated as disabled until the
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callback is set.
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@param ptr A user-supplied pointer to give to the callback.
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@param flags Any number of LEV_OPT_* flags
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@param backlog Passed to the listen() call to determine the length of the
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acceptable connection backlog. Set to -1 for a reasonable default.
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@param sa The address to listen for connections on.
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@param socklen The length of the address.
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*/
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EVENT2_EXPORT_SYMBOL
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struct evconnlistener *evconnlistener_new_bind(struct event_base *base,
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evconnlistener_cb cb, void *ptr, unsigned flags, int backlog,
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const struct sockaddr *sa, int socklen);
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/**
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Disable and deallocate an evconnlistener.
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*/
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EVENT2_EXPORT_SYMBOL
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void evconnlistener_free(struct evconnlistener *lev);
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/**
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Re-enable an evconnlistener that has been disabled.
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*/
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EVENT2_EXPORT_SYMBOL
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int evconnlistener_enable(struct evconnlistener *lev);
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/**
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Stop listening for connections on an evconnlistener.
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*/
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EVENT2_EXPORT_SYMBOL
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int evconnlistener_disable(struct evconnlistener *lev);
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/** Return an evconnlistener's associated event_base. */
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EVENT2_EXPORT_SYMBOL
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struct event_base *evconnlistener_get_base(struct evconnlistener *lev);
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/** Return the socket that an evconnlistner is listening on. */
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EVENT2_EXPORT_SYMBOL
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evutil_socket_t evconnlistener_get_fd(struct evconnlistener *lev);
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/** Change the callback on the listener to cb and its user_data to arg.
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*/
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EVENT2_EXPORT_SYMBOL
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void evconnlistener_set_cb(struct evconnlistener *lev,
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evconnlistener_cb cb, void *arg);
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/** Set an evconnlistener's error callback. */
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EVENT2_EXPORT_SYMBOL
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void evconnlistener_set_error_cb(struct evconnlistener *lev,
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evconnlistener_errorcb errorcb);
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#ifdef __cplusplus
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}
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#endif
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#endif
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