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3 (C) 2009, 2010 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"
44 * Largest supported message.
46 #define GNUNET_SERVER_MAX_MESSAGE_SIZE 65536
49 * Largest supported message.
51 #define GNUNET_SERVER_MIN_BUFFER_SIZE sizeof (struct GNUNET_MessageHeader)
54 * @brief handle for a server
56 struct GNUNET_SERVER_Handle;
60 * @brief opaque handle for a client of the server
62 struct GNUNET_SERVER_Client;
66 * Functions with this signature are called whenever a message is
70 * @param client identification of the client
71 * @param message the actual message
73 typedef void (*GNUNET_SERVER_MessageCallback) (void *cls,
74 struct GNUNET_SERVER_Client *
77 GNUNET_MessageHeader *
83 * Message handler. Each struct specifies how to handle on particular
84 * type of message received.
86 struct GNUNET_SERVER_MessageHandler
89 * Function to call for messages of "type".
91 GNUNET_SERVER_MessageCallback callback;
94 * Closure argument for "callback".
99 * Type of the message this handler covers.
104 * Expected size of messages of this type. Use 0 for
105 * variable-size. If non-zero, messages of the given
106 * type will be discarded (and the connection closed)
107 * if they do not have the right size.
109 uint16_t expected_size;
115 * Create a new server.
117 * @param access function for access control
118 * @param access_cls closure for access
119 * @param lsocks NULL-terminated array of listen 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 *
127 GNUNET_SERVER_create_with_sockets (GNUNET_CONNECTION_AccessCheck access, void *access_cls,
128 struct GNUNET_NETWORK_Handle **lsocks,
129 struct GNUNET_TIME_Relative
134 * Create a new server.
136 * @param access function for access control
137 * @param access_cls closure for access
138 * @param serverAddr address toes listen on (including port), NULL terminated array
139 * @param socklen lengths of respective serverAddr
140 * @param idle_timeout after how long should we timeout idle connections?
141 * @param require_found if YES, connections sending messages of unknown type
143 * @return handle for the new server, NULL on error
144 * (typically, "port" already in use)
146 struct GNUNET_SERVER_Handle *GNUNET_SERVER_create (GNUNET_CONNECTION_AccessCheck
147 access, void *access_cls,
148 struct sockaddr *const*serverAddr,
149 const socklen_t *socklen,
150 struct GNUNET_TIME_Relative
156 * Free resources held by this server.
158 * @param s server to destroy
160 void GNUNET_SERVER_destroy (struct GNUNET_SERVER_Handle *s);
164 * Add additional handlers to an existing server.
166 * @param server the server to add handlers to
167 * @param handlers array of message handlers for
168 * incoming messages; the last entry must
169 * have "NULL" for the "callback"; multiple
170 * entries for the same type are allowed,
171 * they will be called in order of occurence.
172 * These handlers can be removed later;
173 * the handlers array must exist until removed
174 * (or server is destroyed).
177 GNUNET_SERVER_add_handlers (struct GNUNET_SERVER_Handle *server,
178 const struct GNUNET_SERVER_MessageHandler
183 * Notify us when the server has enough space to transmit
184 * a message of the given size to the given client.
186 * @param client client to transmit message to
187 * @param size requested amount of buffer space
188 * @param timeout after how long should we give up (and call
189 * notify with buf NULL and size 0)?
190 * @param callback function to call when space is available
191 * @param callback_cls closure for callback
192 * @return non-NULL if the notify callback was queued; can be used
193 * to cancel the request using
194 * GNUNET_CONNECTION_notify_transmit_ready_cancel.
195 * NULL if we are already going to notify someone else (busy)
197 struct GNUNET_CONNECTION_TransmitHandle
198 *GNUNET_SERVER_notify_transmit_ready (struct GNUNET_SERVER_Client *client,
200 struct GNUNET_TIME_Relative timeout,
201 GNUNET_CONNECTION_TransmitReadyNotify
202 callback, void *callback_cls);
206 * Set the persistent flag on this client, used to setup client connection
207 * to only be killed when the service it's connected to is actually dead.
209 * @param client the client to set the persistent flag on
212 GNUNET_SERVER_client_persist_ (struct GNUNET_SERVER_Client *client);
215 * Resume receiving from this client, we are done processing the
216 * current request. This function must be called from within each
217 * GNUNET_SERVER_MessageCallback (or its respective continuations).
219 * @param client client we were processing a message of
220 * @param success GNUNET_OK to keep the connection open and
221 * continue to receive
222 * GNUNET_NO to close the connection (normal behavior)
223 * GNUNET_SYSERR to close the connection (signal
227 GNUNET_SERVER_receive_done (struct GNUNET_SERVER_Client *client, int success);
231 * Change the timeout for a particular client. Decreasing the timeout
232 * may not go into effect immediately (only after the previous timeout
233 * times out or activity happens on the socket).
235 * @param client the client to update
236 * @param timeout new timeout for activities on the socket
239 GNUNET_SERVER_client_set_timeout (struct GNUNET_SERVER_Client *client,
240 struct GNUNET_TIME_Relative timeout);
244 * Disable the warning the server issues if a message is not acknowledged
245 * in a timely fashion. Use this call if a client is intentionally delayed
246 * for a while. Only applies to the current message.
248 * @param client client for which to disable the warning
251 GNUNET_SERVER_disable_receive_done_warning (struct GNUNET_SERVER_Client *client);
255 * Inject a message into the server, pretend it came
256 * from the specified client. Delivery of the message
257 * will happen instantly (if a handler is installed;
258 * otherwise the call does nothing).
260 * @param server the server receiving the message
261 * @param sender the "pretended" sender of the message
263 * @param message message to transmit
264 * @return GNUNET_OK if the message was OK and the
265 * connection can stay open
266 * GNUNET_SYSERR if the connection to the
267 * client should be shut down
270 GNUNET_SERVER_inject (struct GNUNET_SERVER_Handle *server,
271 struct GNUNET_SERVER_Client *sender,
272 const struct GNUNET_MessageHeader *message);
276 * Add a TCP socket-based connection to the set of handles managed by
277 * this server. Use this function for outgoing (P2P) connections that
278 * we initiated (and where this server should process incoming
281 * @param server the server to use
282 * @param connection the connection to manage (client must
283 * stop using this connection from now on)
284 * @return the client handle (client should call
285 * "client_drop" on the return value eventually)
287 struct GNUNET_SERVER_Client *GNUNET_SERVER_connect_socket (struct
291 GNUNET_CONNECTION_Handle
296 * Notify the server that the given client handle should
297 * be kept (keeps the connection up if possible, increments
298 * the internal reference counter).
300 * @param client the client to keep
302 void GNUNET_SERVER_client_keep (struct GNUNET_SERVER_Client *client);
306 * Notify the server that the given client handle is no
307 * longer required. Decrements the reference counter. If
308 * that counter reaches zero an inactive connection maybe
311 * @param client the client to drop
313 void GNUNET_SERVER_client_drop (struct GNUNET_SERVER_Client *client);
317 * Obtain the network address of the other party.
319 * @param client the client to get the address for
320 * @param addr where to store the address
321 * @param addrlen where to store the length of the address
322 * @return GNUNET_OK on success
324 int GNUNET_SERVER_client_get_address (struct GNUNET_SERVER_Client *client,
325 void **addr, size_t * addrlen);
329 * Functions with this signature are called whenever a client
330 * is disconnected on the network level.
333 * @param client identification of the client; NULL
334 * for the last call when the server is destroyed
336 typedef void (*GNUNET_SERVER_DisconnectCallback) (void *cls,
337 struct GNUNET_SERVER_Client
342 * Ask the server to notify us whenever a client disconnects.
343 * This function is called whenever the actual network connection
344 * is closed; the reference count may be zero or larger than zero
345 * at this point. If the server is destroyed before this
346 * notification is explicitly cancelled, the 'callback' will
347 * once be called with a 'client' argument of NULL to indicate
348 * that the server itself is now gone (and that the callback
349 * won't be called anymore and also can no longer be cancelled).
351 * @param server the server manageing the clients
352 * @param callback function to call on disconnect
353 * @param callback_cls closure for callback
355 void GNUNET_SERVER_disconnect_notify (struct GNUNET_SERVER_Handle *server,
356 GNUNET_SERVER_DisconnectCallback
357 callback, void *callback_cls);
361 * Ask the server to stop notifying us whenever a client disconnects.
363 * @param server the server manageing the clients
364 * @param callback function to call on disconnect
365 * @param callback_cls closure for callback
367 void GNUNET_SERVER_disconnect_notify_cancel (struct GNUNET_SERVER_Handle *server,
368 GNUNET_SERVER_DisconnectCallback
369 callback, void *callback_cls);
373 * Ask the server to disconnect from the given client.
374 * This is the same as returning GNUNET_SYSERR from a message
375 * handler, except that it allows dropping of a client even
376 * when not handling a message from that client.
378 * @param client the client to disconnect from
380 void GNUNET_SERVER_client_disconnect (struct GNUNET_SERVER_Client *client);
384 * Configure this server's connections to continue handling client
385 * requests as usual even after we get a shutdown signal. The change
386 * only applies to clients that connect to the server from the outside
387 * using TCP after this call. Clients managed previously or those
388 * added using GNUNET_SERVER_connect_socket and
389 * GNUNET_SERVER_connect_callback are not affected by this option.
391 * @param h server handle
392 * @param do_ignore GNUNET_YES to ignore, GNUNET_NO to restore default
395 GNUNET_SERVER_ignore_shutdown (struct GNUNET_SERVER_Handle *h,
401 * Disable the "CORK" feature for communication with the given client,
402 * forcing the OS to immediately flush the buffer on transmission
403 * instead of potentially buffering multiple messages.
405 * @param client handle to the client
406 * @return GNUNET_OK on success
409 GNUNET_SERVER_client_disable_corking (struct GNUNET_SERVER_Client *client);
413 * The tansmit context is the key datastructure for a conveniance API
414 * used for transmission of complex results to the client followed
415 * ONLY by signaling receive_done with success or error
417 struct GNUNET_SERVER_TransmitContext;
421 * Create a new transmission context for the
424 * @param client client to create the context for.
425 * @return NULL on error
427 struct GNUNET_SERVER_TransmitContext
428 *GNUNET_SERVER_transmit_context_create (struct GNUNET_SERVER_Client
433 * Append a message to the transmission context.
434 * All messages in the context will be sent by
435 * the transmit_context_run method.
437 * @param tc context to use
438 * @param data what to append to the result message
439 * @param length length of data
440 * @param type type of the message
443 GNUNET_SERVER_transmit_context_append_data (struct GNUNET_SERVER_TransmitContext
444 *tc, const void *data, size_t length,
449 * Append a message to the transmission context.
450 * All messages in the context will be sent by
451 * the transmit_context_run method.
453 * @param tc context to use
454 * @param msg message to append
457 GNUNET_SERVER_transmit_context_append_message (struct GNUNET_SERVER_TransmitContext
458 *tc, const struct GNUNET_MessageHeader *msg);
462 * Execute a transmission context. If there is
463 * an error in the transmission, the receive_done
464 * method will be called with an error code (GNUNET_SYSERR),
465 * otherwise with GNUNET_OK.
467 * @param tc transmission context to use
468 * @param timeout when to time out and abort the transmission
471 GNUNET_SERVER_transmit_context_run (struct GNUNET_SERVER_TransmitContext *tc,
472 struct GNUNET_TIME_Relative timeout);
477 * The notification context is the key datastructure for a conveniance
478 * API used for transmission of notifications to the client until the
479 * client disconnects (or the notification context is destroyed, in
480 * which case we disconnect these clients). Essentially, all
481 * (notification) messages are queued up until the client is able to
484 struct GNUNET_SERVER_NotificationContext;
488 * Create a new notification context.
490 * @param server server for which this function creates the context
491 * @param queue_length maximum number of messages to keep in
492 * the notification queue; optional messages are dropped
493 * if the queue gets longer than this number of messages
494 * @return handle to the notification context
496 struct GNUNET_SERVER_NotificationContext *
497 GNUNET_SERVER_notification_context_create (struct GNUNET_SERVER_Handle *server,
498 unsigned int queue_length);
502 * Destroy the context, force disconnect for all clients.
504 * @param nc context to destroy.
507 GNUNET_SERVER_notification_context_destroy (struct GNUNET_SERVER_NotificationContext *nc);
511 * Add a client to the notification context.
513 * @param nc context to modify
514 * @param client client to add
517 GNUNET_SERVER_notification_context_add (struct GNUNET_SERVER_NotificationContext *nc,
518 struct GNUNET_SERVER_Client *client);
522 * Send a message to a particular client; must have
523 * already been added to the notification context.
525 * @param nc context to modify
526 * @param client client to transmit to
527 * @param msg message to send
528 * @param can_drop can this message be dropped due to queue length limitations
531 GNUNET_SERVER_notification_context_unicast (struct GNUNET_SERVER_NotificationContext *nc,
532 struct GNUNET_SERVER_Client *client,
533 const struct GNUNET_MessageHeader *msg,
538 * Send a message to all clients of this context.
540 * @param nc context to modify
541 * @param msg message to send
542 * @param can_drop can this message be dropped due to queue length limitations
545 GNUNET_SERVER_notification_context_broadcast (struct GNUNET_SERVER_NotificationContext *nc,
546 const struct GNUNET_MessageHeader *msg,
552 * Handle to a message stream tokenizer.
554 struct GNUNET_SERVER_MessageStreamTokenizer;
557 * Functions with this signature are called whenever a
558 * complete message is received by the tokenizer.
561 * @param client identification of the client
562 * @param message the actual message
564 typedef void (*GNUNET_SERVER_MessageTokenizerCallback) (void *cls,
567 GNUNET_MessageHeader *
572 * Create a message stream tokenizer.
574 * @param cb function to call on completed messages
575 * @param cb_cls closure for cb
576 * @return handle to tokenizer
578 struct GNUNET_SERVER_MessageStreamTokenizer *
579 GNUNET_SERVER_mst_create (GNUNET_SERVER_MessageTokenizerCallback cb,
584 * Add incoming data to the receive buffer and call the
585 * callback for all complete messages.
587 * @param mst tokenizer to use
588 * @param client_identity ID of client for which this is a buffer,
589 * can be NULL (will be passed back to 'cb')
590 * @param buf input data to add
591 * @param size number of bytes in buf
592 * @param purge should any excess bytes in the buffer be discarded
593 * (i.e. for packet-based services like UDP)
594 * @param one_shot only call callback once, keep rest of message in buffer
595 * @return GNUNET_OK if we are done processing (need more data)
596 * GNUNET_NO if one_shot was set and we have another message ready
597 * GNUNET_SYSERR if the data stream is corrupt
600 GNUNET_SERVER_mst_receive (struct GNUNET_SERVER_MessageStreamTokenizer *mst,
601 void *client_identity,
609 * Destroys a tokenizer.
611 * @param mst tokenizer to destroy
614 GNUNET_SERVER_mst_destroy (struct GNUNET_SERVER_MessageStreamTokenizer *mst);
617 #if 0 /* keep Emacsens' auto-indent happy */
625 /* ifndef GNUNET_SERVER_LIB_H */
627 /* end of gnunet_server_lib.h */