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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 idle_timeout,
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 *
146 GNUNET_SERVER_create (GNUNET_CONNECTION_AccessCheck access, void *access_cls,
147 struct sockaddr *const *serverAddr,
148 const socklen_t * socklen,
149 struct GNUNET_TIME_Relative idle_timeout,
154 * Free resources held by this server.
156 * @param s server to destroy
159 GNUNET_SERVER_destroy (struct GNUNET_SERVER_Handle *s);
163 * Add additional handlers to an existing server.
165 * @param server the server to add handlers to
166 * @param handlers array of message handlers for
167 * incoming messages; the last entry must
168 * have "NULL" for the "callback"; multiple
169 * entries for the same type are allowed,
170 * they will be called in order of occurence.
171 * These handlers can be removed later;
172 * the handlers array must exist until removed
173 * (or server is destroyed).
176 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
211 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 *
288 GNUNET_SERVER_connect_socket (struct GNUNET_SERVER_Handle *server,
289 struct GNUNET_CONNECTION_Handle *connection);
293 * Notify the server that the given client handle should
294 * be kept (keeps the connection up if possible, increments
295 * the internal reference counter).
297 * @param client the client to keep
300 GNUNET_SERVER_client_keep (struct GNUNET_SERVER_Client *client);
304 * Notify the server that the given client handle is no
305 * longer required. Decrements the reference counter. If
306 * that counter reaches zero an inactive connection maybe
309 * @param client the client to drop
312 GNUNET_SERVER_client_drop (struct GNUNET_SERVER_Client *client);
316 * Obtain the network address of the other party.
318 * @param client the client to get the address for
319 * @param addr where to store the address
320 * @param addrlen where to store the length of the address
321 * @return GNUNET_OK on success
324 GNUNET_SERVER_client_get_address (struct GNUNET_SERVER_Client *client,
325 void **addr, size_t * addrlen);
329 * Retrieve the unique id from the opaque defined GNUNET_SERVER_Client
331 * @param client the client
332 * @return the unique id
335 GNUNET_SERVER_client_get_id (struct GNUNET_SERVER_Client *client);
339 * Functions with this signature are called whenever a client
340 * is disconnected on the network level.
343 * @param client identification of the client; NULL
344 * for the last call when the server is destroyed
346 typedef void (*GNUNET_SERVER_DisconnectCallback) (void *cls,
347 struct GNUNET_SERVER_Client *
352 * Ask the server to notify us whenever a client disconnects.
353 * This function is called whenever the actual network connection
354 * is closed; the reference count may be zero or larger than zero
355 * at this point. If the server is destroyed before this
356 * notification is explicitly cancelled, the 'callback' will
357 * once be called with a 'client' argument of NULL to indicate
358 * that the server itself is now gone (and that the callback
359 * won't be called anymore and also can no longer be cancelled).
361 * @param server the server manageing the clients
362 * @param callback function to call on disconnect
363 * @param callback_cls closure for callback
366 GNUNET_SERVER_disconnect_notify (struct GNUNET_SERVER_Handle *server,
367 GNUNET_SERVER_DisconnectCallback callback,
372 * Ask the server to stop notifying us whenever a client disconnects.
374 * @param server the server manageing the clients
375 * @param callback function to call on disconnect
376 * @param callback_cls closure for callback
379 GNUNET_SERVER_disconnect_notify_cancel (struct GNUNET_SERVER_Handle *server,
380 GNUNET_SERVER_DisconnectCallback
381 callback, void *callback_cls);
385 * Ask the server to disconnect from the given client.
386 * This is the same as returning GNUNET_SYSERR from a message
387 * handler, except that it allows dropping of a client even
388 * when not handling a message from that client.
390 * @param client the client to disconnect from
393 GNUNET_SERVER_client_disconnect (struct GNUNET_SERVER_Client *client);
397 * Configure this server's connections to continue handling client
398 * requests as usual even after we get a shutdown signal. The change
399 * only applies to clients that connect to the server from the outside
400 * using TCP after this call. Clients managed previously or those
401 * added using GNUNET_SERVER_connect_socket and
402 * GNUNET_SERVER_connect_callback are not affected by this option.
404 * @param h server handle
405 * @param do_ignore GNUNET_YES to ignore, GNUNET_NO to restore default
408 GNUNET_SERVER_ignore_shutdown (struct GNUNET_SERVER_Handle *h, int do_ignore);
413 * Disable the "CORK" feature for communication with the given client,
414 * forcing the OS to immediately flush the buffer on transmission
415 * instead of potentially buffering multiple messages.
417 * @param client handle to the client
418 * @return GNUNET_OK on success
421 GNUNET_SERVER_client_disable_corking (struct GNUNET_SERVER_Client *client);
425 * The tansmit context is the key datastructure for a conveniance API
426 * used for transmission of complex results to the client followed
427 * ONLY by signaling receive_done with success or error
429 struct GNUNET_SERVER_TransmitContext;
433 * Create a new transmission context for the
436 * @param client client to create the context for.
437 * @return NULL on error
439 struct GNUNET_SERVER_TransmitContext *
440 GNUNET_SERVER_transmit_context_create (struct GNUNET_SERVER_Client *client);
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 data what to append to the result message
450 * @param length length of data
451 * @param type type of the message
454 GNUNET_SERVER_transmit_context_append_data (struct GNUNET_SERVER_TransmitContext
455 *tc, const void *data,
456 size_t length, uint16_t type);
460 * Append a message to the transmission context.
461 * All messages in the context will be sent by
462 * the transmit_context_run method.
464 * @param tc context to use
465 * @param msg message to append
468 GNUNET_SERVER_transmit_context_append_message (struct
469 GNUNET_SERVER_TransmitContext
471 const struct GNUNET_MessageHeader
476 * Execute a transmission context. If there is
477 * an error in the transmission, the receive_done
478 * method will be called with an error code (GNUNET_SYSERR),
479 * otherwise with GNUNET_OK.
481 * @param tc transmission context to use
482 * @param timeout when to time out and abort the transmission
485 GNUNET_SERVER_transmit_context_run (struct GNUNET_SERVER_TransmitContext *tc,
486 struct GNUNET_TIME_Relative timeout);
491 * The notification context is the key datastructure for a conveniance
492 * API used for transmission of notifications to the client until the
493 * client disconnects (or the notification context is destroyed, in
494 * which case we disconnect these clients). Essentially, all
495 * (notification) messages are queued up until the client is able to
498 struct GNUNET_SERVER_NotificationContext;
502 * Create a new notification context.
504 * @param server server for which this function creates the context
505 * @param queue_length maximum number of messages to keep in
506 * the notification queue; optional messages are dropped
507 * if the queue gets longer than this number of messages
508 * @return handle to the notification context
510 struct GNUNET_SERVER_NotificationContext *
511 GNUNET_SERVER_notification_context_create (struct GNUNET_SERVER_Handle *server,
512 unsigned int queue_length);
516 * Destroy the context, force disconnect for all clients.
518 * @param nc context to destroy.
521 GNUNET_SERVER_notification_context_destroy (struct
522 GNUNET_SERVER_NotificationContext
527 * Add a client to the notification context.
529 * @param nc context to modify
530 * @param client client to add
533 GNUNET_SERVER_notification_context_add (struct GNUNET_SERVER_NotificationContext
535 struct GNUNET_SERVER_Client *client);
539 * Send a message to a particular client; must have
540 * already been added to the notification context.
542 * @param nc context to modify
543 * @param client client to transmit to
544 * @param msg message to send
545 * @param can_drop can this message be dropped due to queue length limitations
548 GNUNET_SERVER_notification_context_unicast (struct
549 GNUNET_SERVER_NotificationContext
551 struct GNUNET_SERVER_Client *client,
552 const struct GNUNET_MessageHeader
557 * Send a message to all clients of this context.
559 * @param nc context to modify
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_broadcast (struct
565 GNUNET_SERVER_NotificationContext
567 const struct GNUNET_MessageHeader
573 * Handle to a message stream tokenizer.
575 struct GNUNET_SERVER_MessageStreamTokenizer;
578 * Functions with this signature are called whenever a
579 * complete message is received by the tokenizer.
582 * @param client identification of the client
583 * @param message the actual message
585 typedef void (*GNUNET_SERVER_MessageTokenizerCallback) (void *cls, void *client,
587 GNUNET_MessageHeader *
592 * Create a message stream tokenizer.
594 * @param cb function to call on completed messages
595 * @param cb_cls closure for cb
596 * @return handle to tokenizer
598 struct GNUNET_SERVER_MessageStreamTokenizer *
599 GNUNET_SERVER_mst_create (GNUNET_SERVER_MessageTokenizerCallback cb,
604 * Add incoming data to the receive buffer and call the
605 * callback for all complete messages.
607 * @param mst tokenizer to use
608 * @param client_identity ID of client for which this is a buffer,
609 * can be NULL (will be passed back to 'cb')
610 * @param buf input data to add
611 * @param size number of bytes in buf
612 * @param purge should any excess bytes in the buffer be discarded
613 * (i.e. for packet-based services like UDP)
614 * @param one_shot only call callback once, keep rest of message in buffer
615 * @return GNUNET_OK if we are done processing (need more data)
616 * GNUNET_NO if one_shot was set and we have another message ready
617 * GNUNET_SYSERR if the data stream is corrupt
620 GNUNET_SERVER_mst_receive (struct GNUNET_SERVER_MessageStreamTokenizer *mst,
621 void *client_identity, const char *buf, size_t size,
622 int purge, int one_shot);
626 * Destroys a tokenizer.
628 * @param mst tokenizer to destroy
631 GNUNET_SERVER_mst_destroy (struct GNUNET_SERVER_MessageStreamTokenizer *mst);
634 #if 0 /* keep Emacsens' auto-indent happy */
642 /* ifndef GNUNET_SERVER_LIB_H */
644 /* end of gnunet_server_lib.h */