libevent (2.1.12)
1 /*
2 * Copyright (c) 2000-2007 Niels Provos <provos@citi.umich.edu>
3 * Copyright (c) 2007-2012 Niels Provos and Nick Mathewson
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
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.
15 *
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
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27 #ifndef EVENT2_LISTENER_H_INCLUDED_
28 #define EVENT2_LISTENER_H_INCLUDED_
29
30 #include <event2/visibility.h>
31
32 #ifdef __cplusplus
33 extern "C" {
34 #endif
35
36 #include <event2/event.h>
37
38 struct sockaddr;
39 struct evconnlistener;
40
41 /**
42 A callback that we invoke when a listener has a new connection.
43
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()
49 */
50 typedef void (*evconnlistener_cb)(struct evconnlistener *, evutil_socket_t, struct sockaddr *, int socklen, void *);
51
52 /**
53 A callback that we invoke when a listener encounters a non-retriable error.
54
55 @param listener The evconnlistener
56 @param user_arg the pointer passed to evconnlistener_new()
57 */
58 typedef void (*evconnlistener_errorcb)(struct evconnlistener *, void *);
59
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
64 * socket. */
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.
79 *
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
84 * connection.
85 *
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.
89 */
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.
93 *
94 * SO_REUSEPORT is what most people would expect SO_REUSEADDR to be, however
95 * SO_REUSEPORT does not imply SO_REUSEADDR.
96 *
97 * This is only available on Linux and kernel 3.9+
98 */
99 #define LEV_OPT_REUSEABLE_PORT (1u<<7)
100 /** Flag: Indicates that the listener wants to work only in IPv6 socket.
101 *
102 * According to RFC3493 and most Linux distributions, default value is to
103 * work in IPv4-mapped mode. If there is a requirement to bind same port
104 * on same ip addresses but different handlers for both IPv4 and IPv6,
105 * it is required to set IPV6_V6ONLY socket option to be sure that the
106 * code works as expected without affected by bindv6only sysctl setting in
107 * system.
108 *
109 * This socket option also supported by Windows.
110 */
111 #define LEV_OPT_BIND_IPV6ONLY (1u<<8)
112
113 /**
114 Allocate a new evconnlistener object to listen for incoming TCP connections
115 on a given file descriptor.
116
117 @param base The event base to associate the listener with.
118 @param cb A callback to be invoked when a new connection arrives. If the
119 callback is NULL, the listener will be treated as disabled until the
120 callback is set.
121 @param ptr A user-supplied pointer to give to the callback.
122 @param flags Any number of LEV_OPT_* flags
123 @param backlog Passed to the listen() call to determine the length of the
124 acceptable connection backlog. Set to -1 for a reasonable default.
125 Set to 0 if the socket is already listening.
126 @param fd The file descriptor to listen on. It must be a nonblocking
127 file descriptor, and it should already be bound to an appropriate
128 port and address.
129 */
130 EVENT2_EXPORT_SYMBOL
131 struct evconnlistener *evconnlistener_new(struct event_base *base,
132 evconnlistener_cb cb, void *ptr, unsigned flags, int backlog,
133 evutil_socket_t fd);
134 /**
135 Allocate a new evconnlistener object to listen for incoming TCP connections
136 on a given address.
137
138 @param base The event base to associate the listener with.
139 @param cb A callback to be invoked when a new connection arrives. If the
140 callback is NULL, the listener will be treated as disabled until the
141 callback is set.
142 @param ptr A user-supplied pointer to give to the callback.
143 @param flags Any number of LEV_OPT_* flags
144 @param backlog Passed to the listen() call to determine the length of the
145 acceptable connection backlog. Set to -1 for a reasonable default.
146 @param addr The address to listen for connections on.
147 @param socklen The length of the address.
148 */
149 EVENT2_EXPORT_SYMBOL
150 struct evconnlistener *evconnlistener_new_bind(struct event_base *base,
151 evconnlistener_cb cb, void *ptr, unsigned flags, int backlog,
152 const struct sockaddr *sa, int socklen);
153 /**
154 Disable and deallocate an evconnlistener.
155 */
156 EVENT2_EXPORT_SYMBOL
157 void evconnlistener_free(struct evconnlistener *lev);
158 /**
159 Re-enable an evconnlistener that has been disabled.
160 */
161 EVENT2_EXPORT_SYMBOL
162 int evconnlistener_enable(struct evconnlistener *lev);
163 /**
164 Stop listening for connections on an evconnlistener.
165 */
166 EVENT2_EXPORT_SYMBOL
167 int evconnlistener_disable(struct evconnlistener *lev);
168
169 /** Return an evconnlistener's associated event_base. */
170 EVENT2_EXPORT_SYMBOL
171 struct event_base *evconnlistener_get_base(struct evconnlistener *lev);
172
173 /** Return the socket that an evconnlistner is listening on. */
174 EVENT2_EXPORT_SYMBOL
175 evutil_socket_t evconnlistener_get_fd(struct evconnlistener *lev);
176
177 /** Change the callback on the listener to cb and its user_data to arg.
178 */
179 EVENT2_EXPORT_SYMBOL
180 void evconnlistener_set_cb(struct evconnlistener *lev,
181 evconnlistener_cb cb, void *arg);
182
183 /** Set an evconnlistener's error callback. */
184 EVENT2_EXPORT_SYMBOL
185 void evconnlistener_set_error_cb(struct evconnlistener *lev,
186 evconnlistener_errorcb errorcb);
187
188 #ifdef __cplusplus
189 }
190 #endif
191
192 #endif
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