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      1 /*
      2  * Copyright (c) 2000-2007 Niels Provos <provos (at) 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_
     28 #define _EVENT2_LISTENER_H_
     29 
     30 #ifdef __cplusplus
     31 extern "C" {
     32 #endif
     33 
     34 #include <event2/event.h>
     35 
     36 struct sockaddr;
     37 struct evconnlistener;
     38 
     39 /**
     40    A callback that we invoke when a listener has a new connection.
     41 
     42    @param listener The evconnlistener
     43    @param fd The new file descriptor
     44    @param addr The source address of the connection
     45    @param socklen The length of addr
     46    @param user_arg the pointer passed to evconnlistener_new()
     47  */
     48 typedef void (*evconnlistener_cb)(struct evconnlistener *, evutil_socket_t, struct sockaddr *, int socklen, void *);
     49 
     50 /**
     51    A callback that we invoke when a listener encounters a non-retriable error.
     52 
     53    @param listener The evconnlistener
     54    @param user_arg the pointer passed to evconnlistener_new()
     55  */
     56 typedef void (*evconnlistener_errorcb)(struct evconnlistener *, void *);
     57 
     58 /** Flag: Indicates that we should not make incoming sockets nonblocking
     59  * before passing them to the callback. */
     60 #define LEV_OPT_LEAVE_SOCKETS_BLOCKING	(1u<<0)
     61 /** Flag: Indicates that freeing the listener should close the underlying
     62  * socket. */
     63 #define LEV_OPT_CLOSE_ON_FREE		(1u<<1)
     64 /** Flag: Indicates that we should set the close-on-exec flag, if possible */
     65 #define LEV_OPT_CLOSE_ON_EXEC		(1u<<2)
     66 /** Flag: Indicates that we should disable the timeout (if any) between when
     67  * this socket is closed and when we can listen again on the same port. */
     68 #define LEV_OPT_REUSEABLE		(1u<<3)
     69 /** Flag: Indicates that the listener should be locked so it's safe to use
     70  * from multiple threadcs at once. */
     71 #define LEV_OPT_THREADSAFE		(1u<<4)
     72 
     73 /**
     74    Allocate a new evconnlistener object to listen for incoming TCP connections
     75    on a given file descriptor.
     76 
     77    @param base The event base to associate the listener with.
     78    @param cb A callback to be invoked when a new connection arrives.  If the
     79       callback is NULL, the listener will be treated as disabled until the
     80       callback is set.
     81    @param ptr A user-supplied pointer to give to the callback.
     82    @param flags Any number of LEV_OPT_* flags
     83    @param backlog Passed to the listen() call to determine the length of the
     84       acceptable connection backlog.  Set to -1 for a reasonable default.
     85       Set to 0 if the socket is already listening.
     86    @param fd The file descriptor to listen on.  It must be a nonblocking
     87       file descriptor, and it should already be bound to an appropriate
     88       port and address.
     89 */
     90 struct evconnlistener *evconnlistener_new(struct event_base *base,
     91     evconnlistener_cb cb, void *ptr, unsigned flags, int backlog,
     92     evutil_socket_t fd);
     93 /**
     94    Allocate a new evconnlistener object to listen for incoming TCP connections
     95    on a given address.
     96 
     97    @param base The event base to associate the listener with.
     98    @param cb A callback to be invoked when a new connection arrives. If the
     99       callback is NULL, the listener will be treated as disabled until the
    100       callback is set.
    101    @param ptr A user-supplied pointer to give to the callback.
    102    @param flags Any number of LEV_OPT_* flags
    103    @param backlog Passed to the listen() call to determine the length of the
    104       acceptable connection backlog.  Set to -1 for a reasonable default.
    105    @param addr The address to listen for connections on.
    106    @param socklen The length of the address.
    107  */
    108 struct evconnlistener *evconnlistener_new_bind(struct event_base *base,
    109     evconnlistener_cb cb, void *ptr, unsigned flags, int backlog,
    110     const struct sockaddr *sa, int socklen);
    111 /**
    112    Disable and deallocate an evconnlistener.
    113  */
    114 void evconnlistener_free(struct evconnlistener *lev);
    115 /**
    116    Re-enable an evconnlistener that has been disabled.
    117  */
    118 int evconnlistener_enable(struct evconnlistener *lev);
    119 /**
    120    Stop listening for connections on an evconnlistener.
    121  */
    122 int evconnlistener_disable(struct evconnlistener *lev);
    123 
    124 /** Return an evconnlistener's associated event_base. */
    125 struct event_base *evconnlistener_get_base(struct evconnlistener *lev);
    126 
    127 /** Return the socket that an evconnlistner is listening on. */
    128 evutil_socket_t evconnlistener_get_fd(struct evconnlistener *lev);
    129 
    130 /** Change the callback on the listener to cb and its user_data to arg.
    131  */
    132 void evconnlistener_set_cb(struct evconnlistener *lev,
    133     evconnlistener_cb cb, void *arg);
    134 
    135 /** Set an evconnlistener's error callback. */
    136 void evconnlistener_set_error_cb(struct evconnlistener *lev,
    137     evconnlistener_errorcb errorcb);
    138 
    139 #ifdef __cplusplus
    140 }
    141 #endif
    142 
    143 #endif
    144