2 This file is part of GNUnet.
3 (C) 2009, 2010 Christian Grothoff (and other contributing authors)
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13 General Public License for more details.
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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"
41 #include "gnunet_scheduler_lib.h"
45 * Largest supported message.
47 #define GNUNET_SERVER_MAX_MESSAGE_SIZE 65536
51 * @brief handle for a server
53 struct GNUNET_SERVER_Handle;
57 * @brief opaque handle for a client of the server
59 struct GNUNET_SERVER_Client;
63 * Functions with this signature are called whenever a message is
67 * @param client identification of the client
68 * @param message the actual message
70 typedef void (*GNUNET_SERVER_MessageCallback) (void *cls,
71 struct GNUNET_SERVER_Client *
74 GNUNET_MessageHeader *
80 * Message handler. Each struct specifies how to handle on particular
81 * type of message received.
83 struct GNUNET_SERVER_MessageHandler
86 * Function to call for messages of "type".
88 GNUNET_SERVER_MessageCallback callback;
91 * Closure argument for "callback".
96 * Type of the message this handler covers.
101 * Expected size of messages of this type. Use 0 for
102 * variable-size. If non-zero, messages of the given
103 * type will be discarded (and the connection closed)
104 * if they do not have the right size.
106 uint16_t expected_size;
112 * Create a new server.
114 * @param sched scheduler to use
115 * @param access function for access control
116 * @param access_cls closure for access
117 * @param serverAddr address toes listen on (including port), NULL terminated array
118 * @param socklen lengths of respective serverAddr
119 * @param maxbuf maximum write buffer size for accepted 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 *GNUNET_SERVER_create (struct
127 GNUNET_SCHEDULER_Handle
129 GNUNET_CONNECTION_AccessCheck
130 access, void *access_cls,
131 struct sockaddr *const*serverAddr,
132 const socklen_t *socklen,
134 struct GNUNET_TIME_Relative
140 * Free resources held by this server.
142 * @param s server to destroy
144 void GNUNET_SERVER_destroy (struct GNUNET_SERVER_Handle *s);
148 * Add additional handlers to an existing server.
150 * @param server the server to add handlers to
151 * @param handlers array of message handlers for
152 * incoming messages; the last entry must
153 * have "NULL" for the "callback"; multiple
154 * entries for the same type are allowed,
155 * they will be called in order of occurence.
156 * These handlers can be removed later;
157 * the handlers array must exist until removed
158 * (or server is destroyed).
161 GNUNET_SERVER_add_handlers (struct GNUNET_SERVER_Handle *server,
162 const struct GNUNET_SERVER_MessageHandler
167 * Notify us when the server has enough space to transmit
168 * a message of the given size to the given client.
170 * @param client client to transmit message to
171 * @param size requested amount of buffer space
172 * @param timeout after how long should we give up (and call
173 * notify with buf NULL and size 0)?
174 * @param callback function to call when space is available
175 * @param callback_cls closure for callback
176 * @return non-NULL if the notify callback was queued; can be used
177 * to cancel the request using
178 * GNUNET_CONNECTION_notify_transmit_ready_cancel.
179 * NULL if we are already going to notify someone else (busy)
181 struct GNUNET_CONNECTION_TransmitHandle
182 *GNUNET_SERVER_notify_transmit_ready (struct GNUNET_SERVER_Client *client,
184 struct GNUNET_TIME_Relative timeout,
185 GNUNET_CONNECTION_TransmitReadyNotify
186 callback, void *callback_cls);
190 * Set the persistent flag on this client, used to setup client connection
191 * to only be killed when the service it's connected to is actually dead.
193 * @param client the client to set the persistent flag on
196 GNUNET_SERVER_client_persist_ (struct GNUNET_SERVER_Client *client);
199 * Resume receiving from this client, we are done processing the
200 * current request. This function must be called from within each
201 * GNUNET_SERVER_MessageCallback (or its respective continuations).
203 * @param client client we were processing a message of
204 * @param success GNUNET_OK to keep the connection open and
205 * continue to receive
206 * GNUNET_NO to close the connection (normal behavior)
207 * GNUNET_SYSERR to close the connection (signal
211 GNUNET_SERVER_receive_done (struct GNUNET_SERVER_Client *client, int success);
215 * Inject a message into the server, pretend it came
216 * from the specified client. Delivery of the message
217 * will happen instantly (if a handler is installed;
218 * otherwise the call does nothing).
220 * @param server the server receiving the message
221 * @param sender the "pretended" sender of the message
223 * @param message message to transmit
224 * @return GNUNET_OK if the message was OK and the
225 * connection can stay open
226 * GNUNET_SYSERR if the connection to the
227 * client should be shut down
230 GNUNET_SERVER_inject (struct GNUNET_SERVER_Handle *server,
231 struct GNUNET_SERVER_Client *sender,
232 const struct GNUNET_MessageHeader *message);
236 * Add a TCP socket-based connection to the set of handles managed by
237 * this server. Use this function for outgoing (P2P) connections that
238 * we initiated (and where this server should process incoming
241 * @param server the server to use
242 * @param connection the connection to manage (client must
243 * stop using this connection from now on)
244 * @return the client handle (client should call
245 * "client_drop" on the return value eventually)
247 struct GNUNET_SERVER_Client *GNUNET_SERVER_connect_socket (struct
251 GNUNET_CONNECTION_Handle
256 * Notify the server that the given client handle should
257 * be kept (keeps the connection up if possible, increments
258 * the internal reference counter).
260 * @param client the client to keep
262 void GNUNET_SERVER_client_keep (struct GNUNET_SERVER_Client *client);
266 * Notify the server that the given client handle is no
267 * longer required. Decrements the reference counter. If
268 * that counter reaches zero an inactive connection maybe
271 * @param client the client to drop
273 void GNUNET_SERVER_client_drop (struct GNUNET_SERVER_Client *client);
277 * Obtain the network address of the other party.
279 * @param client the client to get the address for
280 * @param addr where to store the address
281 * @param addrlen where to store the length of the address
282 * @return GNUNET_OK on success
284 int GNUNET_SERVER_client_get_address (struct GNUNET_SERVER_Client *client,
285 void **addr, size_t * addrlen);
289 * Functions with this signature are called whenever a client
290 * is disconnected on the network level.
293 * @param client identification of the client; NULL
294 * for the last call when the server is destroyed
296 typedef void (*GNUNET_SERVER_DisconnectCallback) (void *cls,
297 struct GNUNET_SERVER_Client
302 * Ask the server to notify us whenever a client disconnects.
303 * This function is called whenever the actual network connection
304 * is closed; the reference count may be zero or larger than zero
305 * at this point. If the server is destroyed before this
306 * notification is explicitly cancelled, the 'callback' will
307 * once be called with a 'client' argument of NULL to indicate
308 * that the server itself is now gone (and that the callback
309 * won't be called anymore and also can no longer be cancelled).
311 * @param server the server manageing the clients
312 * @param callback function to call on disconnect
313 * @param callback_cls closure for callback
315 void GNUNET_SERVER_disconnect_notify (struct GNUNET_SERVER_Handle *server,
316 GNUNET_SERVER_DisconnectCallback
317 callback, void *callback_cls);
321 * Ask the server to stop notifying us whenever a client disconnects.
323 * @param server the server manageing the clients
324 * @param callback function to call on disconnect
325 * @param callback_cls closure for callback
327 void GNUNET_SERVER_disconnect_notify_cancel (struct GNUNET_SERVER_Handle *server,
328 GNUNET_SERVER_DisconnectCallback
329 callback, void *callback_cls);
333 * Ask the server to disconnect from the given client.
334 * This is the same as returning GNUNET_SYSERR from a message
335 * handler, except that it allows dropping of a client even
336 * when not handling a message from that client.
338 * @param client the client to disconnect from
340 void GNUNET_SERVER_client_disconnect (struct GNUNET_SERVER_Client *client);
344 * Configure this server's connections to continue handling client
345 * requests as usual even after we get a shutdown signal. The change
346 * only applies to clients that connect to the server from the outside
347 * using TCP after this call. Clients managed previously or those
348 * added using GNUNET_SERVER_connect_socket and
349 * GNUNET_SERVER_connect_callback are not affected by this option.
351 * @param h server handle
352 * @param do_ignore GNUNET_YES to ignore, GNUNET_NO to restore default
355 GNUNET_SERVER_ignore_shutdown (struct GNUNET_SERVER_Handle *h,
361 * The tansmit context is the key datastructure for a conveniance API
362 * used for transmission of complex results to the client followed
363 * ONLY by signaling receive_done with success or error
365 struct GNUNET_SERVER_TransmitContext;
369 * Create a new transmission context for the
372 * @param client client to create the context for.
373 * @return NULL on error
375 struct GNUNET_SERVER_TransmitContext
376 *GNUNET_SERVER_transmit_context_create (struct GNUNET_SERVER_Client
381 * Append a message to the transmission context.
382 * All messages in the context will be sent by
383 * the transmit_context_run method.
385 * @param tc context to use
386 * @param data what to append to the result message
387 * @param length length of data
388 * @param type type of the message
391 GNUNET_SERVER_transmit_context_append_data (struct GNUNET_SERVER_TransmitContext
392 *tc, const void *data, size_t length,
397 * Append a message to the transmission context.
398 * All messages in the context will be sent by
399 * the transmit_context_run method.
401 * @param tc context to use
402 * @param msg message to append
405 GNUNET_SERVER_transmit_context_append_message (struct GNUNET_SERVER_TransmitContext
406 *tc, const struct GNUNET_MessageHeader *msg);
410 * Execute a transmission context. If there is
411 * an error in the transmission, the receive_done
412 * method will be called with an error code (GNUNET_SYSERR),
413 * otherwise with GNUNET_OK.
415 * @param tc transmission context to use
416 * @param timeout when to time out and abort the transmission
419 GNUNET_SERVER_transmit_context_run (struct GNUNET_SERVER_TransmitContext *tc,
420 struct GNUNET_TIME_Relative timeout);
425 * The notification context is the key datastructure for a conveniance
426 * API used for transmission of notifications to the client until the
427 * client disconnects (or the notification context is destroyed, in
428 * which case we disconnect these clients). Essentially, all
429 * (notification) messages are queued up until the client is able to
432 struct GNUNET_SERVER_NotificationContext;
436 * Create a new notification context.
438 * @param server server for which this function creates the context
439 * @param queue_length maximum number of messages to keep in
440 * the notification queue; optional messages are dropped
441 * it the queue gets longer than this number of messages
442 * @return handle to the notification context
444 struct GNUNET_SERVER_NotificationContext *
445 GNUNET_SERVER_notification_context_create (struct GNUNET_SERVER_Handle *server,
446 unsigned int queue_length);
450 * Destroy the context, force disconnect for all clients.
452 * @param nc context to destroy.
455 GNUNET_SERVER_notification_context_destroy (struct GNUNET_SERVER_NotificationContext *nc);
459 * Add a client to the notification context.
461 * @param nc context to modify
462 * @param client client to add
465 GNUNET_SERVER_notification_context_add (struct GNUNET_SERVER_NotificationContext *nc,
466 struct GNUNET_SERVER_Client *client);
470 * Send a message to a particular client; must have
471 * already been added to the notification context.
473 * @param nc context to modify
474 * @param client client to transmit to
475 * @param msg message to send
476 * @param can_drop can this message be dropped due to queue length limitations
479 GNUNET_SERVER_notification_context_unicast (struct GNUNET_SERVER_NotificationContext *nc,
480 struct GNUNET_SERVER_Client *client,
481 const struct GNUNET_MessageHeader *msg,
486 * Send a message to all clients of this context.
488 * @param nc context to modify
489 * @param msg message to send
490 * @param can_drop can this message be dropped due to queue length limitations
493 GNUNET_SERVER_notification_context_broadcast (struct GNUNET_SERVER_NotificationContext *nc,
494 const struct GNUNET_MessageHeader *msg,
500 * Handle to a message stream tokenizer.
502 struct GNUNET_SERVER_MessageStreamTokenizer;
505 * Functions with this signature are called whenever a
506 * complete message is received by the tokenizer.
509 * @param client identification of the client
510 * @param message the actual message
512 typedef void (*GNUNET_SERVER_MessageTokenizerCallback) (void *cls,
515 GNUNET_MessageHeader *
520 * Create a message stream tokenizer.
522 * @param maxbuf maximum message size to support (typically
523 * GNUNET_SERVER_MAX_MESSAGE_SIZE)
524 * @param client_identity ID of client for which this is a buffer,
525 * can be NULL (will be passed back to 'cb')
526 * @param cb function to call on completed messages
527 * @param cb_cls closure for cb
528 * @return handle to tokenizer
530 struct GNUNET_SERVER_MessageStreamTokenizer *
531 GNUNET_SERVER_mst_create (size_t maxbuf,
532 GNUNET_SERVER_MessageTokenizerCallback cb,
537 * Add incoming data to the receive buffer and call the
538 * callback for all complete messages.
540 * @param mst tokenizer to use
541 * @param buf input data to add
542 * @param size number of bytes in buf
543 * @param purge should any excess bytes in the buffer be discarded
544 * (i.e. for packet-based services like UDP)
545 * @param one_shot only call callback once, keep rest of message in buffer
546 * @return GNUNET_OK if we are done processing (need more data)
547 * GNUNET_NO if one_shot was set and we have another message ready
548 * GNUNET_SYSERR if the data stream is corrupt
551 GNUNET_SERVER_mst_receive (struct GNUNET_SERVER_MessageStreamTokenizer *mst,
552 void *client_identity,
560 * Destroys a tokenizer.
562 * @param mst tokenizer to destroy
565 GNUNET_SERVER_mst_destroy (struct GNUNET_SERVER_MessageStreamTokenizer *mst);
568 #if 0 /* keep Emacsens' auto-indent happy */
576 /* ifndef GNUNET_SERVER_LIB_H */
578 /* end of gnunet_server_lib.h */