2 * Copyright (c) 2000-2007 Niels Provos <provos@citi.umich.edu>
3 * Copyright (c) 2007-2012 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,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 #ifndef EVENT2_LISTENER_H_INCLUDED_
28 #define EVENT2_LISTENER_H_INCLUDED_
30 #include <event2/visibility.h>
36 #include <event2/event.h>
39 struct evconnlistener;
42 A callback that we invoke when a listener has a new connection.
44 @param listener The evconnlistener
45 @param fd The new file descriptor
46 @param addr The source address of the connection
47 @param socklen The length of addr
48 @param user_arg the pointer passed to evconnlistener_new()
50 typedef void (*evconnlistener_cb)(struct evconnlistener *, evutil_socket_t, struct sockaddr *, int socklen, void *);
53 A callback that we invoke when a listener encounters a non-retriable error.
55 @param listener The evconnlistener
56 @param user_arg the pointer passed to evconnlistener_new()
58 typedef void (*evconnlistener_errorcb)(struct evconnlistener *, void *);
60 /** Flag: Indicates that we should not make incoming sockets nonblocking
61 * before passing them to the callback. */
62 #define LEV_OPT_LEAVE_SOCKETS_BLOCKING (1u<<0)
63 /** Flag: Indicates that freeing the listener should close the underlying
65 #define LEV_OPT_CLOSE_ON_FREE (1u<<1)
66 /** Flag: Indicates that we should set the close-on-exec flag, if possible */
67 #define LEV_OPT_CLOSE_ON_EXEC (1u<<2)
68 /** Flag: Indicates that we should disable the timeout (if any) between when
69 * this socket is closed and when we can listen again on the same port. */
70 #define LEV_OPT_REUSEABLE (1u<<3)
71 /** Flag: Indicates that the listener should be locked so it's safe to use
72 * from multiple threadcs at once. */
73 #define LEV_OPT_THREADSAFE (1u<<4)
74 /** Flag: Indicates that the listener should be created in disabled
75 * state. Use evconnlistener_enable() to enable it later. */
76 #define LEV_OPT_DISABLED (1u<<5)
77 /** Flag: Indicates that the listener should defer accept() until data is
78 * available, if possible. Ignored on platforms that do not support this.
80 * This option can help performance for protocols where the client transmits
81 * immediately after connecting. Do not use this option if your protocol
82 * _doesn't_ start out with the client transmitting data, since in that case
83 * this option will sometimes cause the kernel to never tell you about the
86 * This option is only supported by evconnlistener_new_bind(): it can't
87 * work with evconnlistener_new_fd(), since the listener needs to be told
88 * to use the option before it is actually bound.
90 #define LEV_OPT_DEFERRED_ACCEPT (1u<<6)
91 /** Flag: Indicates that we ask to allow multiple servers (processes or
92 * threads) to bind to the same port if they each set the option.
94 * SO_REUSEPORT is what most people would expect SO_REUSEADDR to be, however
95 * SO_REUSEPORT does not imply SO_REUSEADDR.
97 * This is only available on Linux and kernel 3.9+
99 #define LEV_OPT_REUSEABLE_PORT (1u<<7)
102 Allocate a new evconnlistener object to listen for incoming TCP connections
103 on a given file descriptor.
105 @param base The event base to associate the listener with.
106 @param cb A callback to be invoked when a new connection arrives. If the
107 callback is NULL, the listener will be treated as disabled until the
109 @param ptr A user-supplied pointer to give to the callback.
110 @param flags Any number of LEV_OPT_* flags
111 @param backlog Passed to the listen() call to determine the length of the
112 acceptable connection backlog. Set to -1 for a reasonable default.
113 Set to 0 if the socket is already listening.
114 @param fd The file descriptor to listen on. It must be a nonblocking
115 file descriptor, and it should already be bound to an appropriate
119 struct evconnlistener *evconnlistener_new(struct event_base *base,
120 evconnlistener_cb cb, void *ptr, unsigned flags, int backlog,
123 Allocate a new evconnlistener object to listen for incoming TCP connections
126 @param base The event base to associate the listener with.
127 @param cb A callback to be invoked when a new connection arrives. If the
128 callback is NULL, the listener will be treated as disabled until the
130 @param ptr A user-supplied pointer to give to the callback.
131 @param flags Any number of LEV_OPT_* flags
132 @param backlog Passed to the listen() call to determine the length of the
133 acceptable connection backlog. Set to -1 for a reasonable default.
134 @param addr The address to listen for connections on.
135 @param socklen The length of the address.
138 struct evconnlistener *evconnlistener_new_bind(struct event_base *base,
139 evconnlistener_cb cb, void *ptr, unsigned flags, int backlog,
140 const struct sockaddr *sa, int socklen);
142 Disable and deallocate an evconnlistener.
145 void evconnlistener_free(struct evconnlistener *lev);
147 Re-enable an evconnlistener that has been disabled.
150 int evconnlistener_enable(struct evconnlistener *lev);
152 Stop listening for connections on an evconnlistener.
155 int evconnlistener_disable(struct evconnlistener *lev);
157 /** Return an evconnlistener's associated event_base. */
159 struct event_base *evconnlistener_get_base(struct evconnlistener *lev);
161 /** Return the socket that an evconnlistner is listening on. */
163 evutil_socket_t evconnlistener_get_fd(struct evconnlistener *lev);
165 /** Change the callback on the listener to cb and its user_data to arg.
168 void evconnlistener_set_cb(struct evconnlistener *lev,
169 evconnlistener_cb cb, void *arg);
171 /** Set an evconnlistener's error callback. */
173 void evconnlistener_set_error_cb(struct evconnlistener *lev,
174 evconnlistener_errorcb errorcb);