X-Git-Url: http://git.meshlink.io/?a=blobdiff_plain;f=avahi-common%2Fdefs.h;h=4efa5ad5ab51955f91ed3096d47434d7d6d76666;hb=451be30b300b390b46738af3fd24fc942ba3158f;hp=8167f34fb26a41748f7a6a823d48d5dd2776e9a4;hpb=e2f7e83d25a5f0966938163c18b1fd8c399393b1;p=catta diff --git a/avahi-common/defs.h b/avahi-common/defs.h index 8167f34..4efa5ad 100644 --- a/avahi-common/defs.h +++ b/avahi-common/defs.h @@ -33,17 +33,17 @@ * 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 + * \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 + * \li the D-Bus API: an extensive D-Bus 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 + * C. (i.e. Python) + * \li avahi-client: a simplifying C wrapper around the D-Bus API. We + * recommend to use this API in C or C++ progams. The D-Bus internals * are hidden completely. * * All three APIs are very similar, however avahi-core is the most powerful. @@ -60,52 +60,52 @@ * Please note that these compatibility layers are incomplete and * generally a waste of resources. We strongly encourage everyone to * use our native APIs for newly written programs and to port older - * programs to one of them! + * programs to avahi-client! * * \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 + * - 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 + * avahi_client_errno() + * - 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 function avahi_client_new() returns 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 uses a simple event loop abstraction laye. A table AvahiPoll + * which contains function pointers for user defined timeout and I/O + * condition event source implementations needs to be passed to * 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. + * AvahiSimplePoll. An adpater for the Qt main loop is available from + * avahi_qt_poll_get(). * * \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 + * pointer to avahi_client_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. + * AVAHI_SERVER_COLLISION or AVAHI_SERVER_REGISTERING state. Your + * services may no be reachable anymore since the local host name is + * no longer established or is currently in the process of being + * 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()) @@ -118,11 +118,16 @@ * 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, use the AVAHI_PUBLISH_UPDATE flag. 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. + * - When you need to modify your services (i.e. change the TXT data + * or the port number), use the AVAHI_PUBLISH_UPDATE flag. Please do + * not free the entry group and create a new one. This would inhibit + * some traffic limiting algorithms in mDNS. When changing just the + * TXT data avahi_entry_group_update_txt() is a shortcut for + * AVAHI_PUBLISH_UPDATE. Please note that you cannot use + * AVAHI_PUBLISH_UPDATE when changing the service name! Renaming a + * DNS-SD service is identical to deleting and creating a new one, and + * that's exactly what you should do in that case. First call + * avahi_entry_group_reset() to remove it and than readd it normally. * * \section good_browse How to Browse for Services * @@ -136,11 +141,55 @@ * - 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. + * traffic immensly. In addition not all DNS-SD implementations + * announce their services in away that they can be found with + * avahi_server_type_browser_new(). * - 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. - * + * + * \section daemon_dies How to Write a Client That Can Deal with Daemon Restarts + * + * With Avahi it is possible to write client applications that can + * deal with Avahi daemon restarts. To accomplish that make sure to + * pass AVAHI_CLIENT_NO_FAIL to avahi_client_new()'s flags + * parameter. That way avahi_client_new() will succeed even when the + * daemon is not running. In that case the object will enter + * AVAHI_CLIENT_CONNECTING state. As soon as the daemon becomes + * available the object will enter one of the AVAHI_CLIENT_S_xxx + * states. Make sure to not create browsers or entry groups before the + * client object has entered one of those states. As usual you will be + * informed about state changes with the callback function supplied to + * avahi_client_new(). If the client is forced to disconnect from the + * server it will enter AVAHI_CLIENT_FAILURE state with + * avahi_client_errno() == AVAHI_ERR_DISCONNECTED. Free the + * AvahiClient object in that case and reconnect to the server anew - + * again with passing AVAHI_CLIENT_NO_FAIL to avahi_client_new(). + * + * We encourage to implement this in all software where service + * discovery is not an integral part of application. e.g. use it in + * all kinds of background daemons, but not in software like iChat + * compatible IM software. + * + * For now AVAHI_CLIENT_NO_FAIL cannot deal with D-Bus daemon restarts. + * + * \section domains How to Deal Properly with Browsing Domains + * + * Due to the introduction of wide-area DNS-SD the correct handling of + * domains becomes more important for Avahi enabled applications. All + * applications that offer the user a list of services discovered with + * Avahi should offer some kind of editable drop down box where the + * user can either enter his own domain or select one of those offered + * by AvahiDomainBrowser. The default domain to browse should be the + * one returned by avahi_client_get_domain_name(). The list of domains + * returned by AvahiDomainBrowser is assembled by the browsing domains + * configured in the daemon's configuration file, the domains + * announced inside the default domain, the domains set with the + * environment variable $AVAHI_BROWSE_DOMAINS (colon-seperated) on the + * client side and the domains set in the XDG configuration file + * ~/.config/avahi/browse-domains on the client side (seperated by + * newlines). File managers offering some kind of "Network + * Neighborhood" folder should show the entries of the default domain + * right inside that and offer subfolders for the browsing domains + * returned by AvahiDomainBrowser. */ AVAHI_C_DECL_BEGIN @@ -172,7 +221,9 @@ typedef enum { AVAHI_PUBLISH_ALLOW_MULTIPLE = 8, /**< For raw records: Allow multiple local records of this type, even if they are intended to be unique */ AVAHI_PUBLISH_NO_REVERSE = 16, /**< For address records: don't create a reverse (PTR) entry */ AVAHI_PUBLISH_NO_COOKIE = 32, /**< For service records: do not implicitly add the local service cookie to TXT data */ - AVAHI_PUBLISH_UPDATE = 64 /**< Update existing records instead of adding new ones */ + AVAHI_PUBLISH_UPDATE = 64, /**< Update existing records instead of adding new ones */ + AVAHI_PUBLISH_USE_WIDE_AREA = 128, /**< Register the record using wide area DNS (i.e. unicast DNS update) */ + AVAHI_PUBLISH_USE_MULTICAST = 256 /**< Register the record using multicast DNS */ } AvahiPublishFlags; /** Some flags for lookup functions */