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22 * @author Christian Grothoff
25 * Functions related to accessing services
27 * @defgroup client Client library
28 * Generic client-side communication with services
30 * @see [Documentation](https://gnunet.org/ipc)
35 #ifndef GNUNET_CLIENT_LIB_H
36 #define GNUNET_CLIENT_LIB_H
41 #if 0 /* keep Emacsens' auto-indent happy */
48 * Opaque handle for a connection to a service.
50 struct GNUNET_CLIENT_Connection;
53 * Get a connection with a service.
55 * @param service_name name of the service
56 * @param cfg configuration to use
57 * @return NULL on error (service unknown to configuration)
59 struct GNUNET_CLIENT_Connection *
60 GNUNET_CLIENT_connect (const char *service_name,
61 const struct GNUNET_CONFIGURATION_Handle *cfg);
65 * Destroy connection with the service. This will automatically
66 * cancel any pending "receive" request (however, the handler will
67 * *NOT* be called, not even with a NULL message). Any pending
68 * transmission request will also be cancelled UNLESS the callback for
69 * the transmission request has already been called, in which case the
70 * transmission 'finish_pending_write' argument determines whether or
71 * not the write is guaranteed to complete before the socket is fully
72 * destroyed (unless, of course, there is an error with the server in
73 * which case the message may still be lost).
75 * @param client handle to the service connection
78 GNUNET_CLIENT_disconnect (struct GNUNET_CLIENT_Connection *client);
82 * Type of a function to call when we receive a message
86 * @param msg message received, NULL on timeout or fatal error
88 typedef void (*GNUNET_CLIENT_MessageHandler) (void *cls,
89 const struct GNUNET_MessageHeader *msg);
93 * Read from the service.
95 * @param client connection to the service
96 * @param handler function to call with the message
97 * @param handler_cls closure for @a handler
98 * @param timeout how long to wait until timing out
101 GNUNET_CLIENT_receive (struct GNUNET_CLIENT_Connection *client,
102 GNUNET_CLIENT_MessageHandler handler, void *handler_cls,
103 struct GNUNET_TIME_Relative timeout);
107 * Transmit handle for client connections.
109 struct GNUNET_CLIENT_TransmitHandle;
113 * Ask the client to call us once the specified number of bytes
114 * are free in the transmission buffer. Will never call the @a notify
115 * callback in this task, but always first go into the scheduler.
117 * @param client connection to the service
118 * @param size number of bytes to send
119 * @param timeout after how long should we give up (and call
120 * @a notify with buf NULL and size 0)?
121 * @param auto_retry if the connection to the service dies, should we
122 * automatically re-connect and retry (within the timeout period)
123 * or should we immediately fail in this case? Pass #GNUNET_YES
124 * if the caller does not care about temporary connection errors,
125 * for example because the protocol is stateless
126 * @param notify function to call
127 * @param notify_cls closure for @a notify
128 * @return NULL if someone else is already waiting to be notified
129 * non-NULL if the notify callback was queued (can be used to cancel
130 * using #GNUNET_CONNECTION_notify_transmit_ready_cancel)
132 struct GNUNET_CLIENT_TransmitHandle *
133 GNUNET_CLIENT_notify_transmit_ready (struct GNUNET_CLIENT_Connection *client,
135 struct GNUNET_TIME_Relative timeout,
137 GNUNET_CONNECTION_TransmitReadyNotify notify,
142 * Cancel a request for notification.
144 * @param th handle from the original request.
147 GNUNET_CLIENT_notify_transmit_ready_cancel (struct GNUNET_CLIENT_TransmitHandle
152 * Convenience API that combines sending a request
153 * to the service and waiting for a response.
154 * If either operation times out, the callback
155 * will be called with a "NULL" response (in which
156 * case the connection should probably be destroyed).
158 * @param client connection to use
159 * @param hdr message to transmit
160 * @param timeout when to give up (for both transmission
161 * and for waiting for a response)
162 * @param auto_retry if the connection to the service dies, should we
163 * automatically re-connect and retry (within the timeout period)
164 * or should we immediately fail in this case? Pass #GNUNET_YES
165 * if the caller does not care about temporary connection errors,
166 * for example because the protocol is stateless
167 * @param rn function to call with the response
168 * @param rn_cls closure for @a rn
169 * @return #GNUNET_OK on success, #GNUNET_SYSERR if a request
173 GNUNET_CLIENT_transmit_and_get_response (struct GNUNET_CLIENT_Connection *client,
174 const struct GNUNET_MessageHeader *hdr,
175 struct GNUNET_TIME_Relative timeout,
177 GNUNET_CLIENT_MessageHandler rn,
182 * Handle for a test to check if a service is running.
184 struct GNUNET_CLIENT_TestHandle;
187 * Function called with the result on the service test.
190 * @param result #GNUNET_YES if the service is running,
191 * #GNUNET_NO if the service is not running
192 * #GNUNET_SYSERR if the configuration is invalid
194 typedef void (*GNUNET_CLIENT_TestResultCallback)(void *cls,
199 * Test if the service is running. If we are given a UNIXPATH or a
200 * local address, we do this NOT by trying to connect to the service,
201 * but by trying to BIND to the same port. If the BIND fails, we know
202 * the service is running.
204 * @param service name of the service to wait for
205 * @param cfg configuration to use
206 * @param timeout how long to wait at most
207 * @param cb function to call with the result
208 * @param cb_cls closure for @a cb
209 * @return handle to cancel the test
211 struct GNUNET_CLIENT_TestHandle *
212 GNUNET_CLIENT_service_test (const char *service,
213 const struct GNUNET_CONFIGURATION_Handle *cfg,
214 struct GNUNET_TIME_Relative timeout,
215 GNUNET_CLIENT_TestResultCallback cb, void *cb_cls);
219 * Abort testing for service.
221 * @param th test handle
224 GNUNET_CLIENT_service_test_cancel (struct GNUNET_CLIENT_TestHandle *th);
227 #if 0 /* keep Emacsens' auto-indent happy */
234 /* ifndef GNUNET_CLIENT_LIB_H */
237 /** @} */ /* end of group client */
239 /* end of gnunet_client_lib.h */