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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 * Smallest supported message.
51 #define GNUNET_SERVER_MIN_BUFFER_SIZE sizeof (struct GNUNET_MessageHeader)
54 * @brief handle for a server
56 struct GNUNET_SERVER_Handle;
59 * @brief opaque handle for a client of the server
61 struct GNUNET_SERVER_Client;
64 * @brief opaque handle server returns for aborting transmission to a client.
66 struct GNUNET_SERVER_TransmitHandle;
70 * Functions with this signature are called whenever a message is
74 * @param client identification of the client
75 * @param message the actual message
77 typedef void (*GNUNET_SERVER_MessageCallback) (void *cls,
78 struct GNUNET_SERVER_Client *
80 const struct GNUNET_MessageHeader
86 * Message handler. Each struct specifies how to handle on particular
87 * type of message received.
89 struct GNUNET_SERVER_MessageHandler
92 * Function to call for messages of "type".
94 GNUNET_SERVER_MessageCallback callback;
97 * Closure argument for "callback".
102 * Type of the message this handler covers.
107 * Expected size of messages of this type. Use 0 for
108 * variable-size. If non-zero, messages of the given
109 * type will be discarded (and the connection closed)
110 * if they do not have the right size.
112 uint16_t expected_size;
118 * Create a new server.
120 * @param access function for access control
121 * @param access_cls closure for access
122 * @param lsocks NULL-terminated array of listen sockets
123 * @param idle_timeout after how long should we timeout idle connections?
124 * @param require_found if YES, connections sending messages of unknown type
126 * @return handle for the new server, NULL on error
127 * (typically, "port" already in use)
129 struct GNUNET_SERVER_Handle *
130 GNUNET_SERVER_create_with_sockets (GNUNET_CONNECTION_AccessCheck access,
132 struct GNUNET_NETWORK_Handle **lsocks,
133 struct GNUNET_TIME_Relative idle_timeout,
137 * Create a new server.
139 * @param access function for access control
140 * @param access_cls closure for access
141 * @param serverAddr address toes listen on (including port), NULL terminated array
142 * @param socklen lengths of respective serverAddr
143 * @param idle_timeout after how long should we timeout idle connections?
144 * @param require_found if YES, connections sending messages of unknown type
146 * @return handle for the new server, NULL on error
147 * (typically, "port" already in use)
149 struct GNUNET_SERVER_Handle *
150 GNUNET_SERVER_create (GNUNET_CONNECTION_AccessCheck access, void *access_cls,
151 struct sockaddr *const *serverAddr,
152 const socklen_t * socklen,
153 struct GNUNET_TIME_Relative idle_timeout,
158 * Free resources held by this server.
160 * @param s server to destroy
163 GNUNET_SERVER_destroy (struct GNUNET_SERVER_Handle *s);
167 * Add additional handlers to an existing server.
169 * @param server the server to add handlers to
170 * @param handlers array of message handlers for
171 * incoming messages; the last entry must
172 * have "NULL" for the "callback"; multiple
173 * entries for the same type are allowed,
174 * they will be called in order of occurence.
175 * These handlers can be removed later;
176 * the handlers array must exist until removed
177 * (or server is destroyed).
180 GNUNET_SERVER_add_handlers (struct GNUNET_SERVER_Handle *server,
181 const struct GNUNET_SERVER_MessageHandler
186 * Notify us when the server has enough space to transmit
187 * a message of the given size to the given client.
189 * @param client client to transmit message to
190 * @param size requested amount of buffer space
191 * @param timeout after how long should we give up (and call
192 * notify with buf NULL and size 0)?
193 * @param callback function to call when space is available
194 * @param callback_cls closure for callback
195 * @return non-NULL if the notify callback was queued; can be used
196 * to cancel the request using
197 * GNUNET_SERVER_notify_transmit_ready_cancel.
198 * NULL if we are already going to notify someone else (busy)
200 struct GNUNET_SERVER_TransmitHandle *
201 GNUNET_SERVER_notify_transmit_ready (struct GNUNET_SERVER_Client *client,
203 struct GNUNET_TIME_Relative timeout,
204 GNUNET_CONNECTION_TransmitReadyNotify
205 callback, void *callback_cls);
209 * Abort transmission request.
211 * @param th request to abort
214 GNUNET_SERVER_notify_transmit_ready_cancel (struct GNUNET_SERVER_TransmitHandle *th);
218 * Set the persistent flag on this client, used to setup client connection
219 * to only be killed when the service it's connected to is actually dead.
221 * @param client the client to set the persistent flag on
224 GNUNET_SERVER_client_persist_ (struct GNUNET_SERVER_Client *client);
228 * Resume receiving from this client, we are done processing the
229 * current request. This function must be called from within each
230 * GNUNET_SERVER_MessageCallback (or its respective continuations).
232 * @param client client we were processing a message of
233 * @param success GNUNET_OK to keep the connection open and
234 * continue to receive
235 * GNUNET_NO to close the connection (normal behavior)
236 * GNUNET_SYSERR to close the connection (signal
240 GNUNET_SERVER_receive_done (struct GNUNET_SERVER_Client *client, int success);
244 * Change the timeout for a particular client. Decreasing the timeout
245 * may not go into effect immediately (only after the previous timeout
246 * times out or activity happens on the socket).
248 * @param client the client to update
249 * @param timeout new timeout for activities on the socket
252 GNUNET_SERVER_client_set_timeout (struct GNUNET_SERVER_Client *client,
253 struct GNUNET_TIME_Relative timeout);
257 * Disable the warning the server issues if a message is not acknowledged
258 * in a timely fashion. Use this call if a client is intentionally delayed
259 * for a while. Only applies to the current message.
261 * @param client client for which to disable the warning
264 GNUNET_SERVER_disable_receive_done_warning (struct GNUNET_SERVER_Client
269 * Inject a message into the server, pretend it came
270 * from the specified client. Delivery of the message
271 * will happen instantly (if a handler is installed;
272 * otherwise the call does nothing).
274 * @param server the server receiving the message
275 * @param sender the "pretended" sender of the message
277 * @param message message to transmit
278 * @return GNUNET_OK if the message was OK and the
279 * connection can stay open
280 * GNUNET_SYSERR if the connection to the
281 * client should be shut down
284 GNUNET_SERVER_inject (struct GNUNET_SERVER_Handle *server,
285 struct GNUNET_SERVER_Client *sender,
286 const struct GNUNET_MessageHeader *message);
290 * Add a TCP socket-based connection to the set of handles managed by
291 * this server. Use this function for outgoing (P2P) connections that
292 * we initiated (and where this server should process incoming
295 * @param server the server to use
296 * @param connection the connection to manage (client must
297 * stop using this connection from now on)
298 * @return the client handle (client should call
299 * "client_drop" on the return value eventually)
301 struct GNUNET_SERVER_Client *
302 GNUNET_SERVER_connect_socket (struct GNUNET_SERVER_Handle *server,
303 struct GNUNET_CONNECTION_Handle *connection);
307 * Notify the server that the given client handle should
308 * be kept (keeps the connection up if possible, increments
309 * the internal reference counter).
311 * @param client the client to keep
314 GNUNET_SERVER_client_keep (struct GNUNET_SERVER_Client *client);
318 * Notify the server that the given client handle is no
319 * longer required. Decrements the reference counter. If
320 * that counter reaches zero an inactive connection maybe
323 * @param client the client to drop
326 GNUNET_SERVER_client_drop (struct GNUNET_SERVER_Client *client);
330 * Obtain the network address of the other party.
332 * @param client the client to get the address for
333 * @param addr where to store the address
334 * @param addrlen where to store the length of the address
335 * @return GNUNET_OK on success
338 GNUNET_SERVER_client_get_address (struct GNUNET_SERVER_Client *client,
339 void **addr, size_t * addrlen);
343 * Functions with this signature are called whenever a client
344 * is disconnected on the network level.
347 * @param client identification of the client; NULL
348 * for the last call when the server is destroyed
350 typedef void (*GNUNET_SERVER_DisconnectCallback) (void *cls,
351 struct GNUNET_SERVER_Client *
356 * Ask the server to notify us whenever a client disconnects.
357 * This function is called whenever the actual network connection
358 * is closed; the reference count may be zero or larger than zero
359 * at this point. If the server is destroyed before this
360 * notification is explicitly cancelled, the 'callback' will
361 * once be called with a 'client' argument of NULL to indicate
362 * that the server itself is now gone (and that the callback
363 * won't be called anymore and also can no longer be cancelled).
365 * @param server the server manageing the clients
366 * @param callback function to call on disconnect
367 * @param callback_cls closure for callback
370 GNUNET_SERVER_disconnect_notify (struct GNUNET_SERVER_Handle *server,
371 GNUNET_SERVER_DisconnectCallback callback,
376 * Ask the server to stop notifying us whenever a client disconnects.
378 * @param server the server manageing the clients
379 * @param callback function to call on disconnect
380 * @param callback_cls closure for callback
383 GNUNET_SERVER_disconnect_notify_cancel (struct GNUNET_SERVER_Handle *server,
384 GNUNET_SERVER_DisconnectCallback
385 callback, void *callback_cls);
389 * Ask the server to disconnect from the given client.
390 * This is the same as returning GNUNET_SYSERR from a message
391 * handler, except that it allows dropping of a client even
392 * when not handling a message from that client.
394 * @param client the client to disconnect from
397 GNUNET_SERVER_client_disconnect (struct GNUNET_SERVER_Client *client);
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 *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 an error in the
465 * transmission, the receive_done method will be called with an error
466 * code (GNUNET_SYSERR), otherwise with GNUNET_OK.
468 * @param tc transmission context to use
469 * @param timeout when to time out and abort the transmission
472 GNUNET_SERVER_transmit_context_run (struct GNUNET_SERVER_TransmitContext *tc,
473 struct GNUNET_TIME_Relative timeout);
477 * Destroy a transmission context. This function must not be called
478 * after 'GNUNET_SERVER_transmit_context_run'.
480 * @param tc transmission context to destroy
481 * @param success code to give to 'GNUNET_SERVER_receive_done' for
482 * the client: GNUNET_OK to keep the connection open and
483 * continue to receive
484 * GNUNET_NO to close the connection (normal behavior)
485 * GNUNET_SYSERR to close the connection (signal
489 GNUNET_SERVER_transmit_context_destroy (struct GNUNET_SERVER_TransmitContext
494 * The notification context is the key datastructure for a conveniance
495 * API used for transmission of notifications to the client until the
496 * client disconnects (or the notification context is destroyed, in
497 * which case we disconnect these clients). Essentially, all
498 * (notification) messages are queued up until the client is able to
501 struct GNUNET_SERVER_NotificationContext;
505 * Create a new notification context.
507 * @param server server for which this function creates the context
508 * @param queue_length maximum number of messages to keep in
509 * the notification queue; optional messages are dropped
510 * if the queue gets longer than this number of messages
511 * @return handle to the notification context
513 struct GNUNET_SERVER_NotificationContext *
514 GNUNET_SERVER_notification_context_create (struct GNUNET_SERVER_Handle *server,
515 unsigned int queue_length);
519 * Destroy the context, force disconnect for all clients.
521 * @param nc context to destroy.
524 GNUNET_SERVER_notification_context_destroy (struct
525 GNUNET_SERVER_NotificationContext
530 * Add a client to the notification context.
532 * @param nc context to modify
533 * @param client client to add
536 GNUNET_SERVER_notification_context_add (struct GNUNET_SERVER_NotificationContext
538 struct GNUNET_SERVER_Client *client);
542 * Send a message to a particular client; must have
543 * already been added to the notification context.
545 * @param nc context to modify
546 * @param client client to transmit to
547 * @param msg message to send
548 * @param can_drop can this message be dropped due to queue length limitations
551 GNUNET_SERVER_notification_context_unicast (struct
552 GNUNET_SERVER_NotificationContext
554 struct GNUNET_SERVER_Client *client,
555 const struct GNUNET_MessageHeader
560 * Send a message to all clients of this context.
562 * @param nc context to modify
563 * @param msg message to send
564 * @param can_drop can this message be dropped due to queue length limitations
567 GNUNET_SERVER_notification_context_broadcast (struct
568 GNUNET_SERVER_NotificationContext
570 const struct GNUNET_MessageHeader
576 * Handle to a message stream tokenizer.
578 struct GNUNET_SERVER_MessageStreamTokenizer;
581 * Functions with this signature are called whenever a
582 * complete message is received by the tokenizer.
585 * @param client identification of the client
586 * @param message the actual message
588 typedef void (*GNUNET_SERVER_MessageTokenizerCallback) (void *cls, void *client,
590 GNUNET_MessageHeader *
595 * Create a message stream tokenizer.
597 * @param cb function to call on completed messages
598 * @param cb_cls closure for cb
599 * @return handle to tokenizer
601 struct GNUNET_SERVER_MessageStreamTokenizer *
602 GNUNET_SERVER_mst_create (GNUNET_SERVER_MessageTokenizerCallback cb,
607 * Add incoming data to the receive buffer and call the
608 * callback for all complete messages.
610 * @param mst tokenizer to use
611 * @param client_identity ID of client for which this is a buffer,
612 * can be NULL (will be passed back to 'cb')
613 * @param buf input data to add
614 * @param size number of bytes in buf
615 * @param purge should any excess bytes in the buffer be discarded
616 * (i.e. for packet-based services like UDP)
617 * @param one_shot only call callback once, keep rest of message in buffer
618 * @return GNUNET_OK if we are done processing (need more data)
619 * GNUNET_NO if one_shot was set and we have another message ready
620 * GNUNET_SYSERR if the data stream is corrupt
623 GNUNET_SERVER_mst_receive (struct GNUNET_SERVER_MessageStreamTokenizer *mst,
624 void *client_identity, const char *buf, size_t size,
625 int purge, int one_shot);
629 * Destroys a tokenizer.
631 * @param mst tokenizer to destroy
634 GNUNET_SERVER_mst_destroy (struct GNUNET_SERVER_MessageStreamTokenizer *mst);
638 * Signature of a function to create a custom tokenizer.
640 * @param cls closure from 'GNUNET_SERVER_set_callbacks'
641 * @param client handle to client the tokenzier will be used for
642 * @return handle to custom tokenizer ('mst')
644 typedef void* (*GNUNET_SERVER_MstCreateCallback) (void *cls,
645 struct GNUNET_SERVER_Client *client);
648 * Signature of a function to destroy a custom tokenizer.
650 * @param cls closure from 'GNUNET_SERVER_set_callbacks'
651 * @param mst custom tokenizer handle
653 typedef void (*GNUNET_SERVER_MstDestroyCallback) (void *cls, void *mst);
656 * Signature of a function to destroy a custom tokenizer.
658 * @param cls closure from 'GNUNET_SERVER_set_callbacks'
659 * @param mst custom tokenizer handle
660 * @param client_identity ID of client for which this is a buffer,
661 * can be NULL (will be passed back to 'cb')
662 * @param buf input data to add
663 * @param size number of bytes in buf
664 * @param purge should any excess bytes in the buffer be discarded
665 * (i.e. for packet-based services like UDP)
666 * @param one_shot only call callback once, keep rest of message in buffer
667 * @return GNUNET_OK if we are done processing (need more data)
668 * GNUNET_NO if one_shot was set and we have another message ready
669 * GNUNET_SYSERR if the data stream is corrupt
671 typedef int (*GNUNET_SERVER_MstReceiveCallback) (void *cls, void *mst,
672 struct GNUNET_SERVER_Client *client,
673 const char *buf, size_t size,
674 int purge, int one_shot);
678 * Change functions used by the server to tokenize the message stream.
679 * (very rarely used).
681 * @param server server to modify
682 * @param create new tokenizer initialization function
683 * @param destroy new tokenizer destruction function
684 * @param receive new tokenizer receive function
685 * @param cls closure for 'create', 'receive', 'destroy'
688 GNUNET_SERVER_set_callbacks (struct GNUNET_SERVER_Handle *server,
689 GNUNET_SERVER_MstCreateCallback create,
690 GNUNET_SERVER_MstDestroyCallback destroy,
691 GNUNET_SERVER_MstReceiveCallback receive,
695 #if 0 /* keep Emacsens' auto-indent happy */
703 /* ifndef GNUNET_SERVER_LIB_H */
705 /* end of gnunet_server_lib.h */