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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 * message);
82 * Message handler. Each struct specifies how to handle on particular
83 * type of message received.
85 struct GNUNET_SERVER_MessageHandler
88 * Function to call for messages of "type".
90 GNUNET_SERVER_MessageCallback callback;
93 * Closure argument for "callback".
98 * Type of the message this handler covers.
103 * Expected size of messages of this type. Use 0 for
104 * variable-size. If non-zero, messages of the given
105 * type will be discarded (and the connection closed)
106 * if they do not have the right size.
108 uint16_t expected_size;
114 * Create a new server.
116 * @param access function for access control
117 * @param access_cls closure for access
118 * @param lsocks NULL-terminated array of listen sockets
119 * @param idle_timeout after how long should we timeout idle connections?
120 * @param require_found if YES, connections sending messages of unknown type
122 * @return handle for the new server, NULL on error
123 * (typically, "port" already in use)
125 struct GNUNET_SERVER_Handle
126 *GNUNET_SERVER_create_with_sockets (GNUNET_CONNECTION_AccessCheck access,
128 struct GNUNET_NETWORK_Handle **lsocks,
129 struct GNUNET_TIME_Relative
130 idle_timeout, int require_found);
133 * Create a new server.
135 * @param access function for access control
136 * @param access_cls closure for access
137 * @param serverAddr address toes listen on (including port), NULL terminated array
138 * @param socklen lengths of respective serverAddr
139 * @param idle_timeout after how long should we timeout idle connections?
140 * @param require_found if YES, connections sending messages of unknown type
142 * @return handle for the new server, NULL on error
143 * (typically, "port" already in use)
145 struct GNUNET_SERVER_Handle *GNUNET_SERVER_create (GNUNET_CONNECTION_AccessCheck
146 access, void *access_cls,
147 struct sockaddr *const
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
211 void GNUNET_SERVER_client_persist_ (struct GNUNET_SERVER_Client *client);
214 * Resume receiving from this client, we are done processing the
215 * current request. This function must be called from within each
216 * GNUNET_SERVER_MessageCallback (or its respective continuations).
218 * @param client client we were processing a message of
219 * @param success GNUNET_OK to keep the connection open and
220 * continue to receive
221 * GNUNET_NO to close the connection (normal behavior)
222 * GNUNET_SYSERR to close the connection (signal
226 GNUNET_SERVER_receive_done (struct GNUNET_SERVER_Client *client, int success);
230 * Change the timeout for a particular client. Decreasing the timeout
231 * may not go into effect immediately (only after the previous timeout
232 * times out or activity happens on the socket).
234 * @param client the client to update
235 * @param timeout new timeout for activities on the socket
238 GNUNET_SERVER_client_set_timeout (struct GNUNET_SERVER_Client *client,
239 struct GNUNET_TIME_Relative timeout);
243 * Disable the warning the server issues if a message is not acknowledged
244 * in a timely fashion. Use this call if a client is intentionally delayed
245 * for a while. Only applies to the current message.
247 * @param client client for which to disable the warning
250 GNUNET_SERVER_disable_receive_done_warning (struct GNUNET_SERVER_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
369 GNUNET_SERVER_DisconnectCallback
370 callback, void *callback_cls);
374 * Ask the server to disconnect from the given client.
375 * This is the same as returning GNUNET_SYSERR from a message
376 * handler, except that it allows dropping of a client even
377 * when not handling a message from that client.
379 * @param client the client to disconnect from
381 void GNUNET_SERVER_client_disconnect (struct GNUNET_SERVER_Client *client);
385 * Configure this server's connections to continue handling client
386 * requests as usual even after we get a shutdown signal. The change
387 * only applies to clients that connect to the server from the outside
388 * using TCP after this call. Clients managed previously or those
389 * added using GNUNET_SERVER_connect_socket and
390 * GNUNET_SERVER_connect_callback are not affected by this option.
392 * @param h server handle
393 * @param do_ignore GNUNET_YES to ignore, GNUNET_NO to restore default
396 GNUNET_SERVER_ignore_shutdown (struct GNUNET_SERVER_Handle *h, int do_ignore);
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
408 int GNUNET_SERVER_client_disable_corking (struct GNUNET_SERVER_Client *client);
412 * The tansmit context is the key datastructure for a conveniance API
413 * used for transmission of complex results to the client followed
414 * ONLY by signaling receive_done with success or error
416 struct GNUNET_SERVER_TransmitContext;
420 * Create a new transmission context for the
423 * @param client client to create the context for.
424 * @return NULL on error
426 struct GNUNET_SERVER_TransmitContext
427 *GNUNET_SERVER_transmit_context_create (struct GNUNET_SERVER_Client
432 * Append a message to the transmission context.
433 * All messages in the context will be sent by
434 * the transmit_context_run method.
436 * @param tc context to use
437 * @param data what to append to the result message
438 * @param length length of data
439 * @param type type of the message
442 GNUNET_SERVER_transmit_context_append_data (struct GNUNET_SERVER_TransmitContext
443 *tc, const void *data,
444 size_t length, uint16_t type);
448 * Append a message to the transmission context.
449 * All messages in the context will be sent by
450 * the transmit_context_run method.
452 * @param tc context to use
453 * @param msg message to append
456 GNUNET_SERVER_transmit_context_append_message (struct
457 GNUNET_SERVER_TransmitContext
459 const struct GNUNET_MessageHeader
464 * Execute a transmission context. If there is
465 * an error in the transmission, the receive_done
466 * method will be called with an error code (GNUNET_SYSERR),
467 * otherwise with GNUNET_OK.
469 * @param tc transmission context to use
470 * @param timeout when to time out and abort the transmission
473 GNUNET_SERVER_transmit_context_run (struct GNUNET_SERVER_TransmitContext *tc,
474 struct GNUNET_TIME_Relative timeout);
479 * The notification context is the key datastructure for a conveniance
480 * API used for transmission of notifications to the client until the
481 * client disconnects (or the notification context is destroyed, in
482 * which case we disconnect these clients). Essentially, all
483 * (notification) messages are queued up until the client is able to
486 struct GNUNET_SERVER_NotificationContext;
490 * Create a new notification context.
492 * @param server server for which this function creates the context
493 * @param queue_length maximum number of messages to keep in
494 * the notification queue; optional messages are dropped
495 * if the queue gets longer than this number of messages
496 * @return handle to the notification context
498 struct GNUNET_SERVER_NotificationContext
499 *GNUNET_SERVER_notification_context_create (struct GNUNET_SERVER_Handle
501 unsigned int queue_length);
505 * Destroy the context, force disconnect for all clients.
507 * @param nc context to destroy.
510 GNUNET_SERVER_notification_context_destroy (struct
511 GNUNET_SERVER_NotificationContext
516 * Add a client to the notification context.
518 * @param nc context to modify
519 * @param client client to add
522 GNUNET_SERVER_notification_context_add (struct GNUNET_SERVER_NotificationContext
524 struct GNUNET_SERVER_Client *client);
528 * Send a message to a particular client; must have
529 * already been added to the notification context.
531 * @param nc context to modify
532 * @param client client to transmit to
533 * @param msg message to send
534 * @param can_drop can this message be dropped due to queue length limitations
537 GNUNET_SERVER_notification_context_unicast (struct
538 GNUNET_SERVER_NotificationContext
540 struct GNUNET_SERVER_Client *client,
541 const struct GNUNET_MessageHeader
546 * Send a message to all clients of this context.
548 * @param nc context to modify
549 * @param msg message to send
550 * @param can_drop can this message be dropped due to queue length limitations
553 GNUNET_SERVER_notification_context_broadcast (struct
554 GNUNET_SERVER_NotificationContext
556 const struct GNUNET_MessageHeader
562 * Handle to a message stream tokenizer.
564 struct GNUNET_SERVER_MessageStreamTokenizer;
567 * Functions with this signature are called whenever a
568 * complete message is received by the tokenizer.
571 * @param client identification of the client
572 * @param message the actual message
574 typedef void (*GNUNET_SERVER_MessageTokenizerCallback) (void *cls,
577 GNUNET_MessageHeader *
582 * Create a message stream tokenizer.
584 * @param cb function to call on completed messages
585 * @param cb_cls closure for cb
586 * @return handle to tokenizer
588 struct GNUNET_SERVER_MessageStreamTokenizer
589 *GNUNET_SERVER_mst_create (GNUNET_SERVER_MessageTokenizerCallback cb,
594 * Add incoming data to the receive buffer and call the
595 * callback for all complete messages.
597 * @param mst tokenizer to use
598 * @param client_identity ID of client for which this is a buffer,
599 * can be NULL (will be passed back to 'cb')
600 * @param buf input data to add
601 * @param size number of bytes in buf
602 * @param purge should any excess bytes in the buffer be discarded
603 * (i.e. for packet-based services like UDP)
604 * @param one_shot only call callback once, keep rest of message in buffer
605 * @return GNUNET_OK if we are done processing (need more data)
606 * GNUNET_NO if one_shot was set and we have another message ready
607 * GNUNET_SYSERR if the data stream is corrupt
610 GNUNET_SERVER_mst_receive (struct GNUNET_SERVER_MessageStreamTokenizer *mst,
611 void *client_identity,
613 size_t size, int purge, int one_shot);
617 * Destroys a tokenizer.
619 * @param mst tokenizer to destroy
622 GNUNET_SERVER_mst_destroy (struct GNUNET_SERVER_MessageStreamTokenizer *mst);
625 #if 0 /* keep Emacsens' auto-indent happy */
633 /* ifndef GNUNET_SERVER_LIB_H */
635 /* end of gnunet_server_lib.h */