2 This file is part of GNUnet.
3 (C) 2009 Christian Grothoff (and other contributing authors)
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12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details.
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22 * @file include/gnunet_server_lib.h
23 * @brief library for building GNUnet network servers
25 * @author Christian Grothoff
28 #ifndef GNUNET_SERVER_LIB_H
29 #define GNUNET_SERVER_LIB_H
34 #if 0 /* keep Emacsens' auto-indent happy */
39 #include "gnunet_common.h"
40 #include "gnunet_connection_lib.h"
41 #include "gnunet_scheduler_lib.h"
45 * Largest supported message.
47 #define GNUNET_SERVER_MAX_MESSAGE_SIZE 65536
51 * @brief handle for a server
53 struct GNUNET_SERVER_Handle;
57 * @brief opaque handle for a client of the server
59 struct GNUNET_SERVER_Client;
63 * Functions with this signature are called whenever a message is
67 * @param client identification of the client
68 * @param message the actual message
70 typedef void (*GNUNET_SERVER_MessageCallback) (void *cls,
71 struct GNUNET_SERVER_Client *
74 GNUNET_MessageHeader *
80 * Message handler. Each struct specifies how to handle on particular
81 * type of message received.
83 struct GNUNET_SERVER_MessageHandler
86 * Function to call for messages of "type".
88 GNUNET_SERVER_MessageCallback callback;
91 * Closure argument for "callback".
96 * Type of the message this handler covers.
101 * Expected size of messages of this type. Use 0 for
102 * variable-size. If non-zero, messages of the given
103 * type will be discarded (and the connection closed)
104 * if they do not have the right size.
106 uint16_t expected_size;
112 * Create a new server.
114 * @param sched scheduler to use
115 * @param access function for access control
116 * @param access_cls closure for access
117 * @param serverAddr address to listen on (including port), use NULL
118 * for internal server (no listening)
119 * @param socklen length of serverAddr
120 * @param maxbuf maximum write buffer size for accepted sockets
121 * @param idle_timeout after how long should we timeout idle connections?
122 * @param require_found if YES, connections sending messages of unknown type
124 * @return handle for the new server, NULL on error
125 * (typically, "port" already in use)
127 struct GNUNET_SERVER_Handle *GNUNET_SERVER_create (struct
128 GNUNET_SCHEDULER_Handle
130 GNUNET_NETWORK_AccessCheck
131 access, void *access_cls,
132 const struct sockaddr
136 struct GNUNET_TIME_Relative
142 * Free resources held by this server.
144 void GNUNET_SERVER_destroy (struct GNUNET_SERVER_Handle *s);
148 * Add additional handlers to an existing server.
150 * @param server the server to add handlers to
151 * @param handlers array of message handlers for
152 * incoming messages; the last entry must
153 * have "NULL" for the "callback"; multiple
154 * entries for the same type are allowed,
155 * they will be called in order of occurence.
156 * These handlers can be removed later;
157 * the handlers array must exist until removed
158 * (or server is destroyed).
161 GNUNET_SERVER_add_handlers (struct GNUNET_SERVER_Handle *server,
162 const struct GNUNET_SERVER_MessageHandler
167 * Notify us when the server has enough space to transmit
168 * a message of the given size to the given client.
170 * @param client client to transmit message to
171 * @param size requested amount of buffer space
172 * @param timeout after how long should we give up (and call
173 * notify with buf NULL and size 0)?
174 * @param callback function to call when space is available
175 * @param callback_cls closure for callback
176 * @return non-NULL if the notify callback was queued; can be used
177 * to cancel the request using
178 * GNUNET_CONNECTION_notify_transmit_ready_cancel.
179 * NULL if we are already going to notify someone else (busy)
181 struct GNUNET_NETWORK_TransmitHandle
182 *GNUNET_SERVER_notify_transmit_ready (struct GNUNET_SERVER_Client *client,
184 struct GNUNET_TIME_Relative timeout,
185 GNUNET_NETWORK_TransmitReadyNotify
186 callback, void *callback_cls);
190 * Resume receiving from this client, we are done processing the
191 * current request. This function must be called from within each
192 * GNUNET_SERVER_MessageCallback (or its respective continuations).
194 * @param client client we were processing a message of
195 * @param success GNUNET_OK to keep the connection open and
196 * continue to receive
197 * GNUNET_SYSERR to close the connection (signal
201 GNUNET_SERVER_receive_done (struct GNUNET_SERVER_Client *client, int success);
205 * Inject a message into the server, pretend it came
206 * from the specified client. Delivery of the message
207 * will happen instantly (if a handler is installed;
208 * otherwise the call does nothing).
210 * @param server the server receiving the message
211 * @param sender the "pretended" sender of the message
213 * @param message message to transmit
214 * @return GNUNET_OK if the message was OK and the
215 * connection can stay open
216 * GNUNET_SYSERR if the connection to the
217 * client should be shut down
220 GNUNET_SERVER_inject (struct GNUNET_SERVER_Handle *server,
221 struct GNUNET_SERVER_Client *sender,
222 const struct GNUNET_MessageHeader *message);
226 * Add a TCP socket-based connection to the set of handles managed by
227 * this server. Use this function for outgoing (P2P) connections that
228 * we initiated (and where this server should process incoming
231 * @param server the server to use
232 * @param connection the connection to manage (client must
233 * stop using this connection from now on)
234 * @return the client handle (client should call
235 * "client_drop" on the return value eventually)
237 struct GNUNET_SERVER_Client *GNUNET_SERVER_connect_socket (struct
241 GNUNET_NETWORK_ConnectionHandle
246 * Receive data from the given connection. This function should call
247 * "receiver" asynchronously using the scheduler. It must return
251 * @param sched scheduler to use
252 * @param max maximum number of bytes to read
253 * @param timeout maximum amount of time to wait (use -1 for "forever")
254 * @param receiver function to call with received data
255 * @param receiver_cls closure for receiver
256 * @return task identifier that can be used to cancel the receive,
257 * GNUNET_SCHEDULER_NO_TASK should be returned
258 * if the receiver function was already called
260 typedef GNUNET_SCHEDULER_TaskIdentifier
261 (*GNUNET_SERVER_ReceiveCallback) (void *cls,
263 struct GNUNET_TIME_Relative timeout,
264 GNUNET_NETWORK_Receiver
265 receiver, void *receiver_cls);
269 * Cancel receive request.
272 * @param ti task identifier from the receive callback
274 typedef void (*GNUNET_SERVER_ReceiveCancelCallback) (void *cls,
275 GNUNET_SCHEDULER_TaskIdentifier
280 * Notify us when the connection is ready to transmit size bytes.
283 * @param size number of bytes to be ready for sending
284 * @param timeout after how long should we give up (and call
285 * notify with buf NULL and size 0)?
286 * @param notify function to call
287 * @param notify_cls closure for notify
288 * @return a handle that can be used to cancel
289 * the transmission request or NULL if
290 * queueing a transmission request failed
292 typedef void *(*GNUNET_SERVER_TransmitReadyCallback) (void *cls,
297 GNUNET_NETWORK_TransmitReadyNotify
303 * Cancel an earlier transmit notification request.
306 * @param ctx handle that was returned by the TransmitReadyCallback
308 typedef void (*GNUNET_SERVER_TransmitReadyCancelCallback) (void *cls,
313 * Check if connection is still valid (no fatal errors have happened so far).
316 * @return GNUNET_YES if valid, GNUNET_NO otherwise
318 typedef int (*GNUNET_SERVER_CheckCallback) (void *cls);
322 * Destroy this connection (free resources).
326 typedef void (*GNUNET_SERVER_DestroyCallback) (void *cls);
330 * Add an arbitrary connection to the set of handles managed by this
331 * server. This can be used if a sending and receiving does not
332 * really go over the network (internal transmission) or for servers
335 * @param server the server to use
336 * @param chandle opaque handle for the connection
337 * @param creceive receive function for the connection
338 * @param creceive_cancel cancel receive function for the connection
339 * @param cnotify transmit notification function for the connection
340 * @param cnotify_cancel transmit notification cancellation function for the connection
341 * @param ccheck function to test if the connection is still up
342 * @param cdestroy function to close and free the connection
343 * @return the client handle (client should call
344 * "client_drop" on the return value eventually)
346 struct GNUNET_SERVER_Client *GNUNET_SERVER_connect_callback (struct
350 GNUNET_SERVER_ReceiveCallback
352 GNUNET_SERVER_ReceiveCancelCallback
354 GNUNET_SERVER_TransmitReadyCallback
356 GNUNET_SERVER_TransmitReadyCancelCallback
358 GNUNET_SERVER_CheckCallback
360 GNUNET_SERVER_DestroyCallback
365 * Notify the server that the given client handle should
366 * be kept (keeps the connection up if possible, increments
367 * the internal reference counter).
369 * @param client the client to keep
371 void GNUNET_SERVER_client_keep (struct GNUNET_SERVER_Client *client);
375 * Notify the server that the given client handle is no
376 * longer required. Decrements the reference counter. If
377 * that counter reaches zero an inactive connection maybe
380 * @param client the client to drop
382 void GNUNET_SERVER_client_drop (struct GNUNET_SERVER_Client *client);
386 * Obtain the network address of the other party.
388 * @param client the client to get the address for
389 * @param addr where to store the address
390 * @param addrlen where to store the length of the address
391 * @return GNUNET_OK on success
393 int GNUNET_SERVER_client_get_address (struct GNUNET_SERVER_Client *client,
394 void **addr, size_t * addrlen);
398 * Functions with this signature are called whenever a client
399 * is disconnected on the network level.
402 * @param client identification of the client
404 typedef void (*GNUNET_SERVER_DisconnectCallback) (void *cls,
405 struct GNUNET_SERVER_Client
410 * Ask the server to notify us whenever a client disconnects.
411 * This function is called whenever the actual network connection
412 * is closed; the reference count may be zero or larger than zero
415 * @param server the server manageing the clients
416 * @param callback function to call on disconnect
417 * @param callback_cls closure for callback
419 void GNUNET_SERVER_disconnect_notify (struct GNUNET_SERVER_Handle *server,
420 GNUNET_SERVER_DisconnectCallback
421 callback, void *callback_cls);
425 * Ask the server to disconnect from the given client.
426 * This is the same as returning GNUNET_SYSERR from a message
427 * handler, except that it allows dropping of a client even
428 * when not handling a message from that client.
430 * @param client the client to disconnect from
432 void GNUNET_SERVER_client_disconnect (struct GNUNET_SERVER_Client *client);
436 * The tansmit context is the key datastructure for a conveniance API
437 * used for transmission of complex results to the client followed
438 * ONLY by signaling receive_done with success or error
440 struct GNUNET_SERVER_TransmitContext;
444 * Create a new transmission context for the
447 * @param client client to create the context for.
448 * @return NULL on error
450 struct GNUNET_SERVER_TransmitContext
451 *GNUNET_SERVER_transmit_context_create (struct GNUNET_SERVER_Client
456 * Append a message to the transmission context.
457 * All messages in the context will be sent by
458 * the transmit_context_run method.
460 * @param tc context to use
461 * @param data what to append to the result message
462 * @param length length of data
463 * @param type type of the message
466 GNUNET_SERVER_transmit_context_append (struct GNUNET_SERVER_TransmitContext
467 *tc, const void *data, size_t length,
471 * Execute a transmission context. If there is
472 * an error in the transmission, the receive_done
473 * method will be called with an error code (GNUNET_SYSERR),
474 * otherwise with GNUNET_OK.
476 * @param tc transmission context to use
477 * @param timeout when to time out and abort the transmission
480 GNUNET_SERVER_transmit_context_run (struct GNUNET_SERVER_TransmitContext *tc,
481 struct GNUNET_TIME_Relative timeout);
485 #if 0 /* keep Emacsens' auto-indent happy */
493 /* ifndef GNUNET_SERVER_LIB_H */
495 /* end of gnunet_server_lib.h */