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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 *
76 const struct GNUNET_MessageHeader
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).
176 void GNUNET_SERVER_add_handlers (struct GNUNET_SERVER_Handle *server,
177 const struct GNUNET_SERVER_MessageHandler
182 * Notify us when the server has enough space to transmit
183 * a message of the given size to the given client.
185 * @param client client to transmit message to
186 * @param size requested amount of buffer space
187 * @param timeout after how long should we give up (and call
188 * notify with buf NULL and size 0)?
189 * @param callback function to call when space is available
190 * @param callback_cls closure for callback
191 * @return non-NULL if the notify callback was queued; can be used
192 * to cancel the request using
193 * GNUNET_CONNECTION_notify_transmit_ready_cancel.
194 * NULL if we are already going to notify someone else (busy)
196 struct GNUNET_CONNECTION_TransmitHandle
197 *GNUNET_SERVER_notify_transmit_ready (struct GNUNET_SERVER_Client *client,
199 struct GNUNET_TIME_Relative timeout,
200 GNUNET_CONNECTION_TransmitReadyNotify
201 callback, void *callback_cls);
205 * Set the persistent flag on this client, used to setup client connection
206 * to only be killed when the service it's connected to is actually dead.
208 * @param client the client to set the persistent flag on
210 void GNUNET_SERVER_client_persist_ (struct GNUNET_SERVER_Client *client);
213 * Resume receiving from this client, we are done processing the
214 * current request. This function must be called from within each
215 * GNUNET_SERVER_MessageCallback (or its respective continuations).
217 * @param client client we were processing a message of
218 * @param success GNUNET_OK to keep the connection open and
219 * continue to receive
220 * GNUNET_NO to close the connection (normal behavior)
221 * GNUNET_SYSERR to close the connection (signal
224 void GNUNET_SERVER_receive_done (struct GNUNET_SERVER_Client *client,
229 * Change the timeout for a particular client. Decreasing the timeout
230 * may not go into effect immediately (only after the previous timeout
231 * times out or activity happens on the socket).
233 * @param client the client to update
234 * @param timeout new timeout for activities on the socket
236 void GNUNET_SERVER_client_set_timeout (struct GNUNET_SERVER_Client *client,
237 struct GNUNET_TIME_Relative timeout);
241 * Disable the warning the server issues if a message is not acknowledged
242 * in a timely fashion. Use this call if a client is intentionally delayed
243 * for a while. Only applies to the current message.
245 * @param client client for which to disable the warning
247 void GNUNET_SERVER_disable_receive_done_warning (struct GNUNET_SERVER_Client
252 * Inject a message into the server, pretend it came
253 * from the specified client. Delivery of the message
254 * will happen instantly (if a handler is installed;
255 * otherwise the call does nothing).
257 * @param server the server receiving the message
258 * @param sender the "pretended" sender of the message
260 * @param message message to transmit
261 * @return GNUNET_OK if the message was OK and the
262 * connection can stay open
263 * GNUNET_SYSERR if the connection to the
264 * client should be shut down
266 int GNUNET_SERVER_inject (struct GNUNET_SERVER_Handle *server,
267 struct GNUNET_SERVER_Client *sender,
268 const struct GNUNET_MessageHeader *message);
272 * Add a TCP socket-based connection to the set of handles managed by
273 * this server. Use this function for outgoing (P2P) connections that
274 * we initiated (and where this server should process incoming
277 * @param server the server to use
278 * @param connection the connection to manage (client must
279 * stop using this connection from now on)
280 * @return the client handle (client should call
281 * "client_drop" on the return value eventually)
283 struct GNUNET_SERVER_Client *GNUNET_SERVER_connect_socket (struct
287 GNUNET_CONNECTION_Handle
292 * Notify the server that the given client handle should
293 * be kept (keeps the connection up if possible, increments
294 * the internal reference counter).
296 * @param client the client to keep
298 void GNUNET_SERVER_client_keep (struct GNUNET_SERVER_Client *client);
302 * Notify the server that the given client handle is no
303 * longer required. Decrements the reference counter. If
304 * that counter reaches zero an inactive connection maybe
307 * @param client the client to drop
309 void GNUNET_SERVER_client_drop (struct GNUNET_SERVER_Client *client);
313 * Obtain the network address of the other party.
315 * @param client the client to get the address for
316 * @param addr where to store the address
317 * @param addrlen where to store the length of the address
318 * @return GNUNET_OK on success
320 int GNUNET_SERVER_client_get_address (struct GNUNET_SERVER_Client *client,
321 void **addr, size_t * addrlen);
325 * Functions with this signature are called whenever a client
326 * is disconnected on the network level.
329 * @param client identification of the client; NULL
330 * for the last call when the server is destroyed
332 typedef void (*GNUNET_SERVER_DisconnectCallback) (void *cls,
333 struct GNUNET_SERVER_Client *
338 * Ask the server to notify us whenever a client disconnects.
339 * This function is called whenever the actual network connection
340 * is closed; the reference count may be zero or larger than zero
341 * at this point. If the server is destroyed before this
342 * notification is explicitly cancelled, the 'callback' will
343 * once be called with a 'client' argument of NULL to indicate
344 * that the server itself is now gone (and that the callback
345 * won't be called anymore and also can no longer be cancelled).
347 * @param server the server manageing the clients
348 * @param callback function to call on disconnect
349 * @param callback_cls closure for callback
351 void GNUNET_SERVER_disconnect_notify (struct GNUNET_SERVER_Handle *server,
352 GNUNET_SERVER_DisconnectCallback callback,
357 * Ask the server to stop notifying us whenever a client disconnects.
359 * @param server the server manageing the clients
360 * @param callback function to call on disconnect
361 * @param callback_cls closure for callback
363 void GNUNET_SERVER_disconnect_notify_cancel (struct GNUNET_SERVER_Handle
365 GNUNET_SERVER_DisconnectCallback
366 callback, void *callback_cls);
370 * Ask the server to disconnect from the given client.
371 * This is the same as returning GNUNET_SYSERR from a message
372 * handler, except that it allows dropping of a client even
373 * when not handling a message from that client.
375 * @param client the client to disconnect from
377 void GNUNET_SERVER_client_disconnect (struct GNUNET_SERVER_Client *client);
381 * Configure this server's connections to continue handling client
382 * requests as usual even after we get a shutdown signal. The change
383 * only applies to clients that connect to the server from the outside
384 * using TCP after this call. Clients managed previously or those
385 * added using GNUNET_SERVER_connect_socket and
386 * GNUNET_SERVER_connect_callback are not affected by this option.
388 * @param h server handle
389 * @param do_ignore GNUNET_YES to ignore, GNUNET_NO to restore default
391 void GNUNET_SERVER_ignore_shutdown (struct GNUNET_SERVER_Handle *h,
397 * Disable the "CORK" feature for communication with the given client,
398 * forcing the OS to immediately flush the buffer on transmission
399 * instead of potentially buffering multiple messages.
401 * @param client handle to the client
402 * @return GNUNET_OK on success
404 int GNUNET_SERVER_client_disable_corking (struct GNUNET_SERVER_Client *client);
408 * The tansmit context is the key datastructure for a conveniance API
409 * used for transmission of complex results to the client followed
410 * ONLY by signaling receive_done with success or error
412 struct GNUNET_SERVER_TransmitContext;
416 * Create a new transmission context for the
419 * @param client client to create the context for.
420 * @return NULL on error
422 struct GNUNET_SERVER_TransmitContext
423 *GNUNET_SERVER_transmit_context_create (struct GNUNET_SERVER_Client
428 * Append a message to the transmission context.
429 * All messages in the context will be sent by
430 * the transmit_context_run method.
432 * @param tc context to use
433 * @param data what to append to the result message
434 * @param length length of data
435 * @param type type of the message
437 void GNUNET_SERVER_transmit_context_append_data (struct
438 GNUNET_SERVER_TransmitContext
439 *tc, const void *data,
440 size_t length, uint16_t type);
444 * Append a message to the transmission context.
445 * All messages in the context will be sent by
446 * the transmit_context_run method.
448 * @param tc context to use
449 * @param msg message to append
451 void GNUNET_SERVER_transmit_context_append_message (struct
452 GNUNET_SERVER_TransmitContext
455 GNUNET_MessageHeader *msg);
459 * Execute a transmission context. If there is
460 * an error in the transmission, the receive_done
461 * method will be called with an error code (GNUNET_SYSERR),
462 * otherwise with GNUNET_OK.
464 * @param tc transmission context to use
465 * @param timeout when to time out and abort the transmission
467 void GNUNET_SERVER_transmit_context_run (struct GNUNET_SERVER_TransmitContext
469 struct GNUNET_TIME_Relative timeout);
474 * The notification context is the key datastructure for a conveniance
475 * API used for transmission of notifications to the client until the
476 * client disconnects (or the notification context is destroyed, in
477 * which case we disconnect these clients). Essentially, all
478 * (notification) messages are queued up until the client is able to
481 struct GNUNET_SERVER_NotificationContext;
485 * Create a new notification context.
487 * @param server server for which this function creates the context
488 * @param queue_length maximum number of messages to keep in
489 * the notification queue; optional messages are dropped
490 * if the queue gets longer than this number of messages
491 * @return handle to the notification context
493 struct GNUNET_SERVER_NotificationContext
494 *GNUNET_SERVER_notification_context_create (struct GNUNET_SERVER_Handle
496 unsigned int queue_length);
500 * Destroy the context, force disconnect for all clients.
502 * @param nc context to destroy.
504 void GNUNET_SERVER_notification_context_destroy (struct
505 GNUNET_SERVER_NotificationContext
510 * Add a client to the notification context.
512 * @param nc context to modify
513 * @param client client to add
515 void GNUNET_SERVER_notification_context_add (struct
516 GNUNET_SERVER_NotificationContext
518 struct GNUNET_SERVER_Client
523 * Send a message to a particular client; must have
524 * already been added to the notification context.
526 * @param nc context to modify
527 * @param client client to transmit to
528 * @param msg message to send
529 * @param can_drop can this message be dropped due to queue length limitations
531 void GNUNET_SERVER_notification_context_unicast (struct
532 GNUNET_SERVER_NotificationContext
534 struct GNUNET_SERVER_Client
537 GNUNET_MessageHeader *msg,
542 * Send a message to all clients of this context.
544 * @param nc context to modify
545 * @param msg message to send
546 * @param can_drop can this message be dropped due to queue length limitations
548 void GNUNET_SERVER_notification_context_broadcast (struct
549 GNUNET_SERVER_NotificationContext
552 GNUNET_MessageHeader *msg,
558 * Handle to a message stream tokenizer.
560 struct GNUNET_SERVER_MessageStreamTokenizer;
563 * Functions with this signature are called whenever a
564 * complete message is received by the tokenizer.
567 * @param client identification of the client
568 * @param message the actual message
570 typedef void (*GNUNET_SERVER_MessageTokenizerCallback) (void *cls, void *client,
572 GNUNET_MessageHeader *
577 * Create a message stream tokenizer.
579 * @param cb function to call on completed messages
580 * @param cb_cls closure for cb
581 * @return handle to tokenizer
583 struct GNUNET_SERVER_MessageStreamTokenizer
584 *GNUNET_SERVER_mst_create (GNUNET_SERVER_MessageTokenizerCallback cb,
589 * Add incoming data to the receive buffer and call the
590 * callback for all complete messages.
592 * @param mst tokenizer to use
593 * @param client_identity ID of client for which this is a buffer,
594 * can be NULL (will be passed back to 'cb')
595 * @param buf input data to add
596 * @param size number of bytes in buf
597 * @param purge should any excess bytes in the buffer be discarded
598 * (i.e. for packet-based services like UDP)
599 * @param one_shot only call callback once, keep rest of message in buffer
600 * @return GNUNET_OK if we are done processing (need more data)
601 * GNUNET_NO if one_shot was set and we have another message ready
602 * GNUNET_SYSERR if the data stream is corrupt
604 int GNUNET_SERVER_mst_receive (struct GNUNET_SERVER_MessageStreamTokenizer *mst,
605 void *client_identity, const char *buf,
606 size_t size, int purge, int one_shot);
610 * Destroys a tokenizer.
612 * @param mst tokenizer to destroy
614 void GNUNET_SERVER_mst_destroy (struct GNUNET_SERVER_MessageStreamTokenizer
618 #if 0 /* keep Emacsens' auto-indent happy */
626 /* ifndef GNUNET_SERVER_LIB_H */
628 /* end of gnunet_server_lib.h */