summaryrefslogtreecommitdiffstats
path: root/avahi-common/defs.h
blob: 6578e2cc8670876389c9c3309a20189b4d06bc2d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
#ifndef foodefshfoo
#define foodefshfoo

/* $Id$ */

/***
  This file is part of avahi.
 
  avahi is free software; you can redistribute it and/or modify it
  under the terms of the GNU Lesser General Public License as
  published by the Free Software Foundation; either version 2.1 of the
  License, or (at your option) any later version.
 
  avahi is distributed in the hope that it will be useful, but WITHOUT
  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
  Public License for more details.
 
  You should have received a copy of the GNU Lesser General Public
  License along with avahi; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  USA.
***/

/** \file defs.h Some common definitions */

#include <avahi-common/cdecl.h>

/** \mainpage
 *  
 * \section choose_api Choosing an API
 *
 * Avahi provides three programming APIs for integration of
 * mDNS/DNS-SD features into your progams:
 *
 * \li avahi-core: an API for embedding a complete mDNS/DNS-SD stack
 * into your software. This is intended for developers of embedded
 * ampliances only. We dissuade from using this API in normal desktop
 * applications since it is not a good idea to run multiple mDNS
 * stacks simultaneously on the same host.
 * \li The DBUS API: an extensive DBUS interface for browsing and
 * registering mDNS/DNS-SD services using avahi-daemon. We recommend
 * to use this API for software written in any language but
 * C. (i.e. python)
 * \li avahi-client: a simplifying C wrapper around the DBUS API. We
 * recommend to use this API in C or C++ progams. The DBUS internals
 * are hidden completely.
 * 
 * All three APIs are very similar, however avahi-core is the most powerful.
 *
 * \section error_reporting Error Reporting
 *
 * Some notes on the Avahi error handling:
 *
 * - Error codes are negative integers and defined as AVAHI_ERR_xx
 * - If a function returns some kind of non-negative integer value
 * on success, a failure is indicated by returning the error code
 * directly.
 * - If a function returns a pointer of some kind on success, a
 * failure is indicated by returning NULL
 * - The last error number may be retrieved by calling
 * avahi_server_errno() (for the server API) or avahi_client_errno()
 * (for the client API)
 * - Just like the libc errno variable the Avahi errno is NOT reset
 * to AVAHI_OK if a function call succeeds.
 * - You may convert a numeric error code into a human readable
 * string using avahi_strerror()
 * - The constructor functions avahi_server_new() and
 * avahi_client_new() return the error code in a call-by-reference
 * argument
 *
 * \section event_loop Event Loop Abstraction
 *
 * Avahi uses for both avahi-client and avahi-core a simple event loop
 * abstraction layer.A table AvahiPoll which contains function
 * pointers for user defined timeout and I/O condition event source
 * implementations, needs to be passed to avahi_server_new() and
 * avahi_client_new(). An adapter for this abstraction layer is
 * available for the GLib main loop in the object AvahiGLibPoll. A
 * simple stand-alone implementation is available under the name
 * AvahiSimplePoll.
 *
 * \section good_publish How to Register Services
 *
 * - Subscribe to server state changes. Pass a callback function
 * pointer to avahi_client_new()/avahi_server_new(). It will be called
 * whenever the server state changes.
 * - Only register your services when the server is in state
 * AVAHI_SERVER_RUNNING. If you register your services in other server
 * states they might not be accessible since the local host name is
 * not established.
 * - Remove your services when the server enters
 * AVAHI_SERVER_COLLISION state. Your services may no be reachable
 * anymore since the local host name is no longer established.
 * - When registering services, use the following algorithm:
 *   - Create a new entry group (i.e. avahi_entry_group_new())
 *   - Add your service(s)/additional host names (i.e. avahi_entry_group_add_service())
 *   - Commit the entry group (i.e. avahi_entry_group_commit())
 * - Subscribe to entry group state changes.
 * - If the entry group enters AVAHI_ENTRY_GROUP_COLLISION state the
 * services of the entry group are automatically removed from the
 * server. You may immediately add your services back to the entry
 * group (but with new names, perhaps using
 * avahi_alternative_service_name()) and commit again. Please do not
 * free the entry group and create a new one. This would inhibit some
 * traffic limiting algorithms in mDNS.
 * - When you need to modify your services, reset the entry group
 * (i.e. avahi_entry_group_reset()) and add them back. Please do not
 * free the entry group and create a new one. This would inhibit some
 * traffic limiting algorithms in mDNS.
 *
 * The linked functions belong to avahi-client. They all have counterparts in the DBUS API and avahi-core.
 *
 * \section good_browse How to Browse for Services
 *
 * - For normal applications you need to call avahi_service_browser_new()
 * for the service type you want to browse for. Use
 * avahi_client_resolve_service() to acquire service data for a a service
 * name.
 * - You can use avahi_domain_browser() to get a list of announced
 * browsing domains. Please note that not all domains whith services
 * on the LAN are mandatorily announced.
 * - Network monitor software may use avahi_service_type_browser_new()
 * to browse for the list of available service types on the LAN. This
 * API should NOT be used in normal software since it increases
 * traffic heavily.
 * - There is no need to subscribe to server state changes.
 *  
 * The linked functions belong to avahi-client. They all have counterparts in the DBUS API and avahi-core.
 *  
 */

#ifndef DOXYGEN_SHOULD_SKIP_THIS
AVAHI_C_DECL_BEGIN
#endif

/** States of an entry group object */
typedef enum {
    AVAHI_ENTRY_GROUP_UNCOMMITED,    /**< The group has not yet been commited, the user must still call avahi_entry_group_commit() */
    AVAHI_ENTRY_GROUP_REGISTERING,   /**< The entries of the group are currently being registered */
    AVAHI_ENTRY_GROUP_ESTABLISHED,   /**< The entries have successfully been established */
    AVAHI_ENTRY_GROUP_COLLISION      /**< A name collision for one of the entries in the group has been detected, the entries have been withdrawn */ 
} AvahiEntryGroupState;

/** The type of domain to browse for */
typedef enum {
    AVAHI_DOMAIN_BROWSER_REGISTER,          /**< Browse for a list of available registering domains */
    AVAHI_DOMAIN_BROWSER_REGISTER_DEFAULT,  /**< Browse for the default registering domain */
    AVAHI_DOMAIN_BROWSER_BROWSE,            /**< Browse for a list of available browsing domains */
    AVAHI_DOMAIN_BROWSER_BROWSE_DEFAULT,    /**< Browse for the default browsing domain */
    AVAHI_DOMAIN_BROWSER_BROWSE_LEGACY,     /**< Legacy browse domain - see DNS-SD spec for more information */
    AVAHI_DOMAIN_BROWSER_MAX
} AvahiDomainBrowserType;

/** Some flags for lookup functions */
typedef enum {
    AVAHI_LOOKUP_NULL = 0,
    AVAHI_LOOKUP_USE_WIDE_AREA = 1,    /**< Force lookup via wide area DNS */
    AVAHI_LOOKUP_USE_MULTICAST = 2,    /**< Force lookup via multicast DNS */
    AVAHI_LOOKUP_NO_TXT = 4,           /**< When doing service resolving, don't lookup TXT record */
    AVAHI_LOOKUP_NO_ADDRESS = 8        /**< When doing service resolving, don't lookup A/AAAA record */
} AvahiLookupFlags;

/** Some flags for lookup callback functions */
typedef enum {
    AVAHI_LOOKUP_CALLBACK_NULL = 0,
    AVAHI_LOOKUP_CALLBACK_CACHED = 1,      /**< This response originates from the cache */
    AVAHI_LOOKUP_CALLBACK_WIDE_AREA = 2,   /**< This response originates from wide area DNS */
    AVAHI_LOOKUP_CALLBACK_MULTICAST = 4,   /**< This response originates from multicast DNS */
} AvahiLookupResultFlags;

/** Type of callback event when browsing */
typedef enum {
    AVAHI_BROWSER_NEW,               /**< The object is new on the network */
    AVAHI_BROWSER_REMOVE,            /**< The object has been removed from the network */
    AVAHI_BROWSER_CACHE_EXHAUSTED,   /**< One-time event, to notify the user that all entries from the caches have been send */
    AVAHI_BROWSER_ALL_FOR_NOW,       /**< One-time event, to notify the user that more records will probably not show up in the near future, i.e. all cache entries have been read and all static servers been queried */
    AVAHI_BROWSER_NOT_FOUND,      /**< Issued when using wide area DNS-SD to inform that a record is not existing */
    AVAHI_BROWSER_FAILURE            /**< Issued when using wide area DNS-SD to inform about server failures */
} AvahiBrowserEvent;

/** Type of callback event when resolving */
typedef enum {
    AVAHI_RESOLVER_FOUND,          /**< RR found, resolving successful */
    AVAHI_RESOLVER_TIMEOUT,        /**< Noone responded within the timeout, resolving failed */
    AVAHI_RESOLVER_NOT_FOUND,      /**< Query was done using wide area DNS-SD and the server told us that the entry is nto available */
    AVAHI_RESOLVER_FAILURE,        /**< Query was done using wide area DNS-SD and the server failed */
} AvahiResolverEvent;

/** States of a server object */
typedef enum {
    AVAHI_SERVER_INVALID,          /**< Invalid state (initial) */ 
    AVAHI_SERVER_REGISTERING,      /**< Host RRs are being registered */
    AVAHI_SERVER_RUNNING,          /**< All host RRs have been established */
    AVAHI_SERVER_COLLISION         /**< There is a collision with a host RR. All host RRs have been withdrawn, the user should set a new host name via avahi_server_set_host_name() */
} AvahiServerState;

/** For every service a special TXT item is implicitly added, which
 * contains a random cookie which is private to the local daemon. This
 * can be used by clients to determine if two services on two
 * different subnets are effectively the same. */
#define AVAHI_SERVICE_COOKIE "org.freedesktop.Avahi.cookie"

/** In invalid cookie as special value */
#define AVAHI_SERVICE_COOKIE_INVALID (0)

#ifndef DOXYGEN_SHOULD_SKIP_THIS
AVAHI_C_DECL_END
#endif

#endif