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 toes listen on (including port), NULL terminated array
118 * @param socklen lengths of respective serverAddr
119 * @param maxbuf maximum write buffer size for accepted sockets
120 * @param idle_timeout after how long should we timeout idle connections?
121 * @param require_found if YES, connections sending messages of unknown type
123 * @return handle for the new server, NULL on error
124 * (typically, "port" already in use)
126 struct GNUNET_SERVER_Handle *GNUNET_SERVER_create (struct
127 GNUNET_SCHEDULER_Handle
129 GNUNET_CONNECTION_AccessCheck
130 access, void *access_cls,
131 struct sockaddr *const*serverAddr,
132 const socklen_t *socklen,
134 struct GNUNET_TIME_Relative
140 * Free resources held by this server.
142 void GNUNET_SERVER_destroy (struct GNUNET_SERVER_Handle *s);
146 * Add additional handlers to an existing server.
148 * @param server the server to add handlers to
149 * @param handlers array of message handlers for
150 * incoming messages; the last entry must
151 * have "NULL" for the "callback"; multiple
152 * entries for the same type are allowed,
153 * they will be called in order of occurence.
154 * These handlers can be removed later;
155 * the handlers array must exist until removed
156 * (or server is destroyed).
159 GNUNET_SERVER_add_handlers (struct GNUNET_SERVER_Handle *server,
160 const struct GNUNET_SERVER_MessageHandler
165 * Notify us when the server has enough space to transmit
166 * a message of the given size to the given client.
168 * @param client client to transmit message to
169 * @param size requested amount of buffer space
170 * @param timeout after how long should we give up (and call
171 * notify with buf NULL and size 0)?
172 * @param callback function to call when space is available
173 * @param callback_cls closure for callback
174 * @return non-NULL if the notify callback was queued; can be used
175 * to cancel the request using
176 * GNUNET_CONNECTION_notify_transmit_ready_cancel.
177 * NULL if we are already going to notify someone else (busy)
179 struct GNUNET_CONNECTION_TransmitHandle
180 *GNUNET_SERVER_notify_transmit_ready (struct GNUNET_SERVER_Client *client,
182 struct GNUNET_TIME_Relative timeout,
183 GNUNET_CONNECTION_TransmitReadyNotify
184 callback, void *callback_cls);
188 * Resume receiving from this client, we are done processing the
189 * current request. This function must be called from within each
190 * GNUNET_SERVER_MessageCallback (or its respective continuations).
192 * @param client client we were processing a message of
193 * @param success GNUNET_OK to keep the connection open and
194 * continue to receive
195 * GNUNET_SYSERR to close the connection (signal
199 GNUNET_SERVER_receive_done (struct GNUNET_SERVER_Client *client, int success);
203 * Inject a message into the server, pretend it came
204 * from the specified client. Delivery of the message
205 * will happen instantly (if a handler is installed;
206 * otherwise the call does nothing).
208 * @param server the server receiving the message
209 * @param sender the "pretended" sender of the message
211 * @param message message to transmit
212 * @return GNUNET_OK if the message was OK and the
213 * connection can stay open
214 * GNUNET_SYSERR if the connection to the
215 * client should be shut down
218 GNUNET_SERVER_inject (struct GNUNET_SERVER_Handle *server,
219 struct GNUNET_SERVER_Client *sender,
220 const struct GNUNET_MessageHeader *message);
224 * Add a TCP socket-based connection to the set of handles managed by
225 * this server. Use this function for outgoing (P2P) connections that
226 * we initiated (and where this server should process incoming
229 * @param server the server to use
230 * @param connection the connection to manage (client must
231 * stop using this connection from now on)
232 * @return the client handle (client should call
233 * "client_drop" on the return value eventually)
235 struct GNUNET_SERVER_Client *GNUNET_SERVER_connect_socket (struct
239 GNUNET_CONNECTION_Handle
244 * Receive data from the given connection. This function should call
245 * "receiver" asynchronously using the scheduler. It must return
249 * @param sched scheduler to use
250 * @param max maximum number of bytes to read
251 * @param timeout maximum amount of time to wait (use -1 for "forever")
252 * @param receiver function to call with received data
253 * @param receiver_cls closure for receiver
256 (*GNUNET_SERVER_ReceiveCallback) (void *cls,
258 struct GNUNET_TIME_Relative timeout,
259 GNUNET_CONNECTION_Receiver
260 receiver, void *receiver_cls);
264 * Cancel receive request.
268 typedef void (*GNUNET_SERVER_ReceiveCancelCallback) (void *cls);
272 * Notify us when the connection is ready to transmit size bytes.
275 * @param size number of bytes to be ready for sending
276 * @param timeout after how long should we give up (and call
277 * notify with buf NULL and size 0)?
278 * @param notify function to call
279 * @param notify_cls closure for notify
280 * @return a handle that can be used to cancel
281 * the transmission request or NULL if
282 * queueing a transmission request failed
284 typedef void *(*GNUNET_SERVER_TransmitReadyCallback) (void *cls,
289 GNUNET_CONNECTION_TransmitReadyNotify
295 * Cancel an earlier transmit notification request.
298 * @param ctx handle that was returned by the TransmitReadyCallback
300 typedef void (*GNUNET_SERVER_TransmitReadyCancelCallback) (void *cls,
305 * Check if connection is still valid (no fatal errors have happened so far).
308 * @return GNUNET_YES if valid, GNUNET_NO otherwise
310 typedef int (*GNUNET_SERVER_CheckCallback) (void *cls);
314 * Destroy this connection (free resources).
318 typedef void (*GNUNET_SERVER_DestroyCallback) (void *cls);
322 * Add an arbitrary connection to the set of handles managed by this
323 * server. This can be used if a sending and receiving does not
324 * really go over the network (internal transmission) or for servers
327 * @param server the server to use
328 * @param chandle opaque handle for the connection
329 * @param creceive receive function for the connection
330 * @param ccancel cancel receive function for the connection
331 * @param cnotify transmit notification function for the connection
332 * @param cnotify_cancel transmit notification cancellation function for the connection
333 * @param ccheck function to test if the connection is still up
334 * @param cdestroy function to close and free the connection
335 * @return the client handle (client should call
336 * "client_drop" on the return value eventually)
338 struct GNUNET_SERVER_Client *GNUNET_SERVER_connect_callback (struct
342 GNUNET_SERVER_ReceiveCallback
344 GNUNET_SERVER_ReceiveCancelCallback
346 GNUNET_SERVER_TransmitReadyCallback
348 GNUNET_SERVER_TransmitReadyCancelCallback
350 GNUNET_SERVER_CheckCallback
352 GNUNET_SERVER_DestroyCallback
357 * Notify the server that the given client handle should
358 * be kept (keeps the connection up if possible, increments
359 * the internal reference counter).
361 * @param client the client to keep
363 void GNUNET_SERVER_client_keep (struct GNUNET_SERVER_Client *client);
367 * Notify the server that the given client handle is no
368 * longer required. Decrements the reference counter. If
369 * that counter reaches zero an inactive connection maybe
372 * @param client the client to drop
374 void GNUNET_SERVER_client_drop (struct GNUNET_SERVER_Client *client);
378 * Obtain the network address of the other party.
380 * @param client the client to get the address for
381 * @param addr where to store the address
382 * @param addrlen where to store the length of the address
383 * @return GNUNET_OK on success
385 int GNUNET_SERVER_client_get_address (struct GNUNET_SERVER_Client *client,
386 void **addr, size_t * addrlen);
390 * Functions with this signature are called whenever a client
391 * is disconnected on the network level.
394 * @param client identification of the client
396 typedef void (*GNUNET_SERVER_DisconnectCallback) (void *cls,
397 struct GNUNET_SERVER_Client
402 * Ask the server to notify us whenever a client disconnects.
403 * This function is called whenever the actual network connection
404 * is closed; the reference count may be zero or larger than zero
407 * @param server the server manageing the clients
408 * @param callback function to call on disconnect
409 * @param callback_cls closure for callback
411 void GNUNET_SERVER_disconnect_notify (struct GNUNET_SERVER_Handle *server,
412 GNUNET_SERVER_DisconnectCallback
413 callback, void *callback_cls);
417 * Ask the server to disconnect from the given client.
418 * This is the same as returning GNUNET_SYSERR from a message
419 * handler, except that it allows dropping of a client even
420 * when not handling a message from that client.
422 * @param client the client to disconnect from
424 void GNUNET_SERVER_client_disconnect (struct GNUNET_SERVER_Client *client);
428 * Configure this server's connections to continue handling client
429 * requests as usual even after we get a shutdown signal. The change
430 * only applies to clients that connect to the server from the outside
431 * using TCP after this call. Clients managed previously or those
432 * added using GNUNET_SERVER_connect_socket and
433 * GNUNET_SERVER_connect_callback are not affected by this option.
435 * @param h server handle
436 * @param do_ignore GNUNET_YES to ignore, GNUNET_NO to restore default
439 GNUNET_SERVER_ignore_shutdown (struct GNUNET_SERVER_Handle *h,
444 * The tansmit context is the key datastructure for a conveniance API
445 * used for transmission of complex results to the client followed
446 * ONLY by signaling receive_done with success or error
448 struct GNUNET_SERVER_TransmitContext;
452 * Create a new transmission context for the
455 * @param client client to create the context for.
456 * @return NULL on error
458 struct GNUNET_SERVER_TransmitContext
459 *GNUNET_SERVER_transmit_context_create (struct GNUNET_SERVER_Client
464 * Append a message to the transmission context.
465 * All messages in the context will be sent by
466 * the transmit_context_run method.
468 * @param tc context to use
469 * @param data what to append to the result message
470 * @param length length of data
471 * @param type type of the message
474 GNUNET_SERVER_transmit_context_append (struct GNUNET_SERVER_TransmitContext
475 *tc, const void *data, size_t length,
479 * Execute a transmission context. If there is
480 * an error in the transmission, the receive_done
481 * method will be called with an error code (GNUNET_SYSERR),
482 * otherwise with GNUNET_OK.
484 * @param tc transmission context to use
485 * @param timeout when to time out and abort the transmission
488 GNUNET_SERVER_transmit_context_run (struct GNUNET_SERVER_TransmitContext *tc,
489 struct GNUNET_TIME_Relative timeout);
493 #if 0 /* keep Emacsens' auto-indent happy */
501 /* ifndef GNUNET_SERVER_LIB_H */
503 /* end of gnunet_server_lib.h */