2 This file is part of GNUnet.
3 (C) 2009 Christian Grothoff (and other contributing authors)
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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 * @param s server to destroy
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_CONNECTION_TransmitHandle
182 *GNUNET_SERVER_notify_transmit_ready (struct GNUNET_SERVER_Client *client,
184 struct GNUNET_TIME_Relative timeout,
185 GNUNET_CONNECTION_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_NO to close the connection (normal behavior)
198 * GNUNET_SYSERR to close the connection (signal
202 GNUNET_SERVER_receive_done (struct GNUNET_SERVER_Client *client, int success);
206 * Inject a message into the server, pretend it came
207 * from the specified client. Delivery of the message
208 * will happen instantly (if a handler is installed;
209 * otherwise the call does nothing).
211 * @param server the server receiving the message
212 * @param sender the "pretended" sender of the message
214 * @param message message to transmit
215 * @return GNUNET_OK if the message was OK and the
216 * connection can stay open
217 * GNUNET_SYSERR if the connection to the
218 * client should be shut down
221 GNUNET_SERVER_inject (struct GNUNET_SERVER_Handle *server,
222 struct GNUNET_SERVER_Client *sender,
223 const struct GNUNET_MessageHeader *message);
227 * Add a TCP socket-based connection to the set of handles managed by
228 * this server. Use this function for outgoing (P2P) connections that
229 * we initiated (and where this server should process incoming
232 * @param server the server to use
233 * @param connection the connection to manage (client must
234 * stop using this connection from now on)
235 * @return the client handle (client should call
236 * "client_drop" on the return value eventually)
238 struct GNUNET_SERVER_Client *GNUNET_SERVER_connect_socket (struct
242 GNUNET_CONNECTION_Handle
247 * Receive data from the given connection. This function should call
248 * "receiver" asynchronously using the scheduler. It must return
252 * @param sched scheduler to use
253 * @param max maximum number of bytes to read
254 * @param timeout maximum amount of time to wait (use -1 for "forever")
255 * @param receiver function to call with received data
256 * @param receiver_cls closure for receiver
259 (*GNUNET_SERVER_ReceiveCallback) (void *cls,
261 struct GNUNET_TIME_Relative timeout,
262 GNUNET_CONNECTION_Receiver
263 receiver, void *receiver_cls);
267 * Cancel receive request.
271 typedef void (*GNUNET_SERVER_ReceiveCancelCallback) (void *cls);
275 * Notify us when the connection is ready to transmit size bytes.
278 * @param size number of bytes to be ready for sending
279 * @param timeout after how long should we give up (and call
280 * notify with buf NULL and size 0)?
281 * @param notify function to call
282 * @param notify_cls closure for notify
283 * @return a handle that can be used to cancel
284 * the transmission request or NULL if
285 * queueing a transmission request failed
287 typedef void *(*GNUNET_SERVER_TransmitReadyCallback) (void *cls,
292 GNUNET_CONNECTION_TransmitReadyNotify
298 * Cancel an earlier transmit notification request.
301 * @param ctx handle that was returned by the TransmitReadyCallback
303 typedef void (*GNUNET_SERVER_TransmitReadyCancelCallback) (void *cls,
308 * Check if connection is still valid (no fatal errors have happened so far).
311 * @return GNUNET_YES if valid, GNUNET_NO otherwise
313 typedef int (*GNUNET_SERVER_CheckCallback) (void *cls);
317 * Destroy this connection (free resources).
321 typedef void (*GNUNET_SERVER_DestroyCallback) (void *cls);
325 * Add an arbitrary connection to the set of handles managed by this
326 * server. This can be used if a sending and receiving does not
327 * really go over the network (internal transmission) or for servers
330 * @param server the server to use
331 * @param chandle opaque handle for the connection
332 * @param creceive receive function for the connection
333 * @param ccancel cancel receive function for the connection
334 * @param cnotify transmit notification function for the connection
335 * @param cnotify_cancel transmit notification cancellation function for the connection
336 * @param ccheck function to test if the connection is still up
337 * @param cdestroy function to close and free the connection
338 * @return the client handle (client should call
339 * "client_drop" on the return value eventually)
341 struct GNUNET_SERVER_Client *GNUNET_SERVER_connect_callback (struct
345 GNUNET_SERVER_ReceiveCallback
347 GNUNET_SERVER_ReceiveCancelCallback
349 GNUNET_SERVER_TransmitReadyCallback
351 GNUNET_SERVER_TransmitReadyCancelCallback
353 GNUNET_SERVER_CheckCallback
355 GNUNET_SERVER_DestroyCallback
360 * Notify the server that the given client handle should
361 * be kept (keeps the connection up if possible, increments
362 * the internal reference counter).
364 * @param client the client to keep
366 void GNUNET_SERVER_client_keep (struct GNUNET_SERVER_Client *client);
370 * Notify the server that the given client handle is no
371 * longer required. Decrements the reference counter. If
372 * that counter reaches zero an inactive connection maybe
375 * @param client the client to drop
377 void GNUNET_SERVER_client_drop (struct GNUNET_SERVER_Client *client);
381 * Obtain the network address of the other party.
383 * @param client the client to get the address for
384 * @param addr where to store the address
385 * @param addrlen where to store the length of the address
386 * @return GNUNET_OK on success
388 int GNUNET_SERVER_client_get_address (struct GNUNET_SERVER_Client *client,
389 void **addr, size_t * addrlen);
393 * Functions with this signature are called whenever a client
394 * is disconnected on the network level.
397 * @param client identification of the client
399 typedef void (*GNUNET_SERVER_DisconnectCallback) (void *cls,
400 struct GNUNET_SERVER_Client
405 * Ask the server to notify us whenever a client disconnects.
406 * This function is called whenever the actual network connection
407 * is closed; the reference count may be zero or larger than zero
410 * @param server the server manageing the clients
411 * @param callback function to call on disconnect
412 * @param callback_cls closure for callback
414 void GNUNET_SERVER_disconnect_notify (struct GNUNET_SERVER_Handle *server,
415 GNUNET_SERVER_DisconnectCallback
416 callback, void *callback_cls);
420 * Ask the server to stop notifying us whenever a client disconnects.
422 * @param server the server manageing the clients
423 * @param callback function to call on disconnect
424 * @param callback_cls closure for callback
426 void GNUNET_SERVER_disconnect_notify_cancel (struct GNUNET_SERVER_Handle *server,
427 GNUNET_SERVER_DisconnectCallback
428 callback, void *callback_cls);
432 * Ask the server to disconnect from the given client.
433 * This is the same as returning GNUNET_SYSERR from a message
434 * handler, except that it allows dropping of a client even
435 * when not handling a message from that client.
437 * @param client the client to disconnect from
439 void GNUNET_SERVER_client_disconnect (struct GNUNET_SERVER_Client *client);
443 * Configure this server's connections to continue handling client
444 * requests as usual even after we get a shutdown signal. The change
445 * only applies to clients that connect to the server from the outside
446 * using TCP after this call. Clients managed previously or those
447 * added using GNUNET_SERVER_connect_socket and
448 * GNUNET_SERVER_connect_callback are not affected by this option.
450 * @param h server handle
451 * @param do_ignore GNUNET_YES to ignore, GNUNET_NO to restore default
454 GNUNET_SERVER_ignore_shutdown (struct GNUNET_SERVER_Handle *h,
460 * The tansmit context is the key datastructure for a conveniance API
461 * used for transmission of complex results to the client followed
462 * ONLY by signaling receive_done with success or error
464 struct GNUNET_SERVER_TransmitContext;
468 * Create a new transmission context for the
471 * @param client client to create the context for.
472 * @return NULL on error
474 struct GNUNET_SERVER_TransmitContext
475 *GNUNET_SERVER_transmit_context_create (struct GNUNET_SERVER_Client
480 * Append a message to the transmission context.
481 * All messages in the context will be sent by
482 * the transmit_context_run method.
484 * @param tc context to use
485 * @param data what to append to the result message
486 * @param length length of data
487 * @param type type of the message
490 GNUNET_SERVER_transmit_context_append (struct GNUNET_SERVER_TransmitContext
491 *tc, const void *data, size_t length,
495 * Execute a transmission context. If there is
496 * an error in the transmission, the receive_done
497 * method will be called with an error code (GNUNET_SYSERR),
498 * otherwise with GNUNET_OK.
500 * @param tc transmission context to use
501 * @param timeout when to time out and abort the transmission
504 GNUNET_SERVER_transmit_context_run (struct GNUNET_SERVER_TransmitContext *tc,
505 struct GNUNET_TIME_Relative timeout);
510 * The notification context is the key datastructure for a conveniance
511 * API used for transmission of notifications to the client until the
512 * client disconnects (or the notification context is destroyed, in
513 * which case we disconnect these clients). Essentially, all
514 * (notification) messages are queued up until the client is able to
517 struct GNUNET_SERVER_NotificationContext;
521 * Create a new notification context.
523 * @param server server for which this function creates the context
524 * @param queue_length maximum number of messages to keep in
525 * the notification queue; optional messages are dropped
526 * it the queue gets longer than this number of messages
527 * @return handle to the notification context
529 struct GNUNET_SERVER_NotificationContext *
530 GNUNET_SERVER_notification_context_create (struct GNUNET_SERVER_Handle *server,
531 unsigned int queue_length);
535 * Destroy the context, force disconnect for all clients.
537 * @param nc context to destroy.
540 GNUNET_SERVER_notification_context_destroy (struct GNUNET_SERVER_NotificationContext *nc);
544 * Add a client to the notification context.
546 * @param nc context to modify
547 * @param client client to add
550 GNUNET_SERVER_notification_context_add (struct GNUNET_SERVER_NotificationContext *nc,
551 struct GNUNET_SERVER_Client *client);
555 * Send a message to a particular client; must have
556 * already been added to the notification context.
558 * @param nc context to modify
559 * @param client client to transmit to
560 * @param msg message to send
561 * @param can_drop can this message be dropped due to queue length limitations
564 GNUNET_SERVER_notification_context_unicast (struct GNUNET_SERVER_NotificationContext *nc,
565 struct GNUNET_SERVER_Client *client,
566 const struct GNUNET_MessageHeader *msg,
571 * Send a message to all clients of this context.
573 * @param nc context to modify
574 * @param msg message to send
575 * @param can_drop can this message be dropped due to queue length limitations
578 GNUNET_SERVER_notification_context_broadcast (struct GNUNET_SERVER_NotificationContext *nc,
579 const struct GNUNET_MessageHeader *msg,
584 #if 0 /* keep Emacsens' auto-indent happy */
592 /* ifndef GNUNET_SERVER_LIB_H */
594 /* end of gnunet_server_lib.h */