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3 (C) 2013 Christian Grothoff (and other contributing authors)
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22 * @file include/gnunet_set_service.h
23 * @brief two-peer set operations
24 * @author Florian Dold
25 * @author Christian Grothoff
28 #ifndef GNUNET_SET_SERVICE_H
29 #define GNUNET_SET_SERVICE_H
34 #if 0 /* keep Emacsens' auto-indent happy */
39 #include "gnunet_common.h"
40 #include "gnunet_time_lib.h"
41 #include "gnunet_configuration_lib.h"
45 * Maximum size of a context message for set operation requests.
47 #define GNUNET_SET_CONTEXT_MESSAGE_MAX_SIZE ((1<<16) - 1024)
51 * Opaque handle to a set.
53 struct GNUNET_SET_Handle;
56 * Opaque handle to a set operation request from another peer.
58 struct GNUNET_SET_Request;
61 * Opaque handle to a listen operation.
63 struct GNUNET_SET_ListenHandle;
66 * Opaque handle to a set operation.
68 struct GNUNET_SET_OperationHandle;
72 * The operation that a set set supports.
74 enum GNUNET_SET_OperationType
77 * A purely local set that does not support any
80 GNUNET_SET_OPERATION_NONE,
83 * Set intersection, only return elements that are in both sets.
85 GNUNET_SET_OPERATION_INTERSECTION,
88 * Set union, return all elements that are in at least one of the sets.
90 GNUNET_SET_OPERATION_UNION
94 * Status for the result callback
96 enum GNUNET_SET_Status
101 GNUNET_SET_STATUS_OK,
104 * There was a timeout.
106 GNUNET_SET_STATUS_TIMEOUT,
109 * The other peer refused to to the operation with us,
110 * or something went wrong.
112 GNUNET_SET_STATUS_FAILURE,
115 * Success, all elements have been returned (but the other
116 * peer might still be receiving some from us, so we are not done).
118 GNUNET_SET_STATUS_HALF_DONE,
121 * Success, all elements have been sent (and received).
123 GNUNET_SET_STATUS_DONE
128 * The way results are given to the client.
130 enum GNUNET_SET_ResultMode
133 * Client gets every element in the resulting set.
135 GNUNET_SET_RESULT_FULL,
138 * Client gets only elements that have been added to the set.
139 * Only works with set union.
141 GNUNET_SET_RESULT_ADDED,
144 * Client gets only elements that have been removed from the set.
145 * Only works with set intersection.
147 GNUNET_SET_RESULT_REMOVED
152 * Element stored in a set.
154 struct GNUNET_SET_Element
157 * Number of bytes in the buffer pointed to by data.
162 * Application-specific element type.
167 * Actual data of the element
174 * Continuation used for some of the set operations
178 typedef void (*GNUNET_SET_Continuation) (void *cls);
182 * Callback for set operation results. Called for each element
186 * @param element a result element, only valid if status is #GNUNET_SET_STATUS_OK
187 * @param status see `enum GNUNET_SET_Status`
189 typedef void (*GNUNET_SET_ResultIterator) (void *cls,
190 const struct GNUNET_SET_Element *element,
191 enum GNUNET_SET_Status status);
194 * Iterator for set elements.
197 * @param element the current element, NULL if all elements have been
199 * @return #GNUNET_YES to continue iterating, #GNUNET_NO to stop.
201 typedef int (*GNUNET_SET_ElementIterator) (void *cls,
202 const struct GNUNET_SET_Element *element);
206 * Called when another peer wants to do a set operation with the
207 * local peer. If a listen error occurs, the @a request is NULL.
210 * @param other_peer the other peer
211 * @param context_msg message with application specific information from
213 * @param request request from the other peer (never NULL), use GNUNET_SET_accept()
214 * to accept it, otherwise the request will be refused
215 * Note that we can't just return value from the listen callback,
216 * as it is also necessary to specify the set we want to do the
217 * operation with, whith sometimes can be derived from the context
218 * message. It's necessary to specify the timeout.
221 (*GNUNET_SET_ListenCallback) (void *cls,
222 const struct GNUNET_PeerIdentity *other_peer,
223 const struct GNUNET_MessageHeader *context_msg,
224 struct GNUNET_SET_Request *request);
229 * Create an empty set, supporting the specified operation.
231 * @param cfg configuration to use for connecting to the
233 * @param op operation supported by the set
234 * Note that the operation has to be specified
235 * beforehand, as certain set operations need to maintain
236 * data structures spefific to the operation
237 * @return a handle to the set
239 struct GNUNET_SET_Handle *
240 GNUNET_SET_create (const struct GNUNET_CONFIGURATION_Handle *cfg,
241 enum GNUNET_SET_OperationType op);
245 * Add an element to the given set.
246 * After the element has been added (in the sense of being
247 * transmitted to the set service), @a cont will be called.
248 * Calls to #GNUNET_SET_add_element can be queued
250 * @param set set to add element to
251 * @param element element to add to the set
252 * @param cont continuation called after the element has been added
253 * @param cont_cls closure for @a cont
254 * @return #GNUNET_OK on success, #GNUNET_SYSERR if the
255 * set is invalid (e.g. the set service crashed)
258 GNUNET_SET_add_element (struct GNUNET_SET_Handle *set,
259 const struct GNUNET_SET_Element *element,
260 GNUNET_SET_Continuation cont,
265 * Remove an element to the given set.
266 * After the element has been removed (in the sense of the
267 * request being transmitted to the set service), cont will be called.
268 * Calls to remove_element can be queued
270 * @param set set to remove element from
271 * @param element element to remove from the set
272 * @param cont continuation called after the element has been removed
273 * @param cont_cls closure for @a cont
274 * @return #GNUNET_OK on success, #GNUNET_SYSERR if the
275 * set is invalid (e.g. the set service crashed)
278 GNUNET_SET_remove_element (struct GNUNET_SET_Handle *set,
279 const struct GNUNET_SET_Element *element,
280 GNUNET_SET_Continuation cont,
285 * Destroy the set handle, and free all associated resources.
288 GNUNET_SET_destroy (struct GNUNET_SET_Handle *set);
292 * Prepare a set operation to be evaluated with another peer.
293 * The evaluation will not start until the client provides
294 * a local set with GNUNET_SET_commit().
296 * @param other_peer peer with the other set
297 * @param app_id hash for the application using the set
298 * @param context_msg additional information for the request
299 * @param salt salt used for the set operation; sometimes set operations
300 * fail due to hash collisions, using a different salt for each operation
301 * makes it harder for an attacker to exploit this
302 * @param result_mode specified how results will be returned,
303 * see `enum GNUNET_SET_ResultMode`.
304 * @param result_cb called on error or success
305 * @param result_cls closure for @a result_cb
306 * @return a handle to cancel the operation
308 struct GNUNET_SET_OperationHandle *
309 GNUNET_SET_prepare (const struct GNUNET_PeerIdentity *other_peer,
310 const struct GNUNET_HashCode *app_id,
311 const struct GNUNET_MessageHeader *context_msg,
313 enum GNUNET_SET_ResultMode result_mode,
314 GNUNET_SET_ResultIterator result_cb,
319 * Wait for set operation requests for the given application ID.
320 * If the connection to the set service is lost, the listener is
321 * re-created transparently with exponential backoff.
323 * @param cfg configuration to use for connecting to
325 * @param operation operation we want to listen for
326 * @param app_id id of the application that handles set operation requests
327 * @param listen_cb called for each incoming request matching the operation
329 * @param listen_cls handle for listen_cb
330 * @return a handle that can be used to cancel the listen operation
332 struct GNUNET_SET_ListenHandle *
333 GNUNET_SET_listen (const struct GNUNET_CONFIGURATION_Handle *cfg,
334 enum GNUNET_SET_OperationType op_type,
335 const struct GNUNET_HashCode *app_id,
336 GNUNET_SET_ListenCallback listen_cb,
341 * Cancel the given listen operation.
342 * After calling cancel, the listen callback for this listen handle
343 * will not be called again.
345 * @param lh handle for the listen operation
348 GNUNET_SET_listen_cancel (struct GNUNET_SET_ListenHandle *lh);
352 * Accept a request we got via GNUNET_SET_listen(). Must be called during
353 * GNUNET_SET_listen(), as the `struct GNUNET_SET_Request` becomes invalid
355 * Call GNUNET_SET_commit() to provide the local set to use for the operation,
356 * and to begin the exchange with the remote peer.
358 * @param request request to accept
359 * @param result_mode specified how results will be returned,
360 * see `enum GNUNET_SET_ResultMode`.
361 * @param result_cb callback for the results
362 * @param result_cls closure for @a result_cb
363 * @return a handle to cancel the operation
365 struct GNUNET_SET_OperationHandle *
366 GNUNET_SET_accept (struct GNUNET_SET_Request *request,
367 enum GNUNET_SET_ResultMode result_mode,
368 GNUNET_SET_ResultIterator result_cb,
373 * Commit a set to be used with a set operation.
374 * This function is called once we have fully constructed
375 * the set that we want to use for the operation. At this
376 * time, the P2P protocol can then begin to exchange the
377 * set information and call the result callback with the
378 * result information.
380 * @param oh handle to the set operation
381 * @param set the set to use for the operation
382 * @return #GNUNET_OK on success, #GNUNET_SYSERR if the
383 * set is invalid (e.g. the set service crashed)
386 GNUNET_SET_commit (struct GNUNET_SET_OperationHandle *oh,
387 struct GNUNET_SET_Handle *set);
391 * Cancel the given set operation.
392 * May not be called after the operation's GNUNET_SET_ResultIterator has been
393 * called with a status that indicates error, timeout or done.
395 * @param oh set operation to cancel
398 GNUNET_SET_operation_cancel (struct GNUNET_SET_OperationHandle *oh);
402 * Iterate over all elements in the given set.
403 * Note that this operation involves transferring every element of the set
404 * from the service to the client, and is thus costly.
405 * Only one iteration per set may be active at the same time.
407 * @param set the set to iterate over
408 * @param iter the iterator to call for each element
409 * @param cls closure for 'iter'
410 * @return GNUNET_YES if the iteration started successfuly,
411 * GNUNET_SYSERR if the set is invalid (e.g. the server crashed, disconnected)
414 GNUNET_SET_iterate (struct GNUNET_SET_Handle *set, GNUNET_SET_ElementIterator iter, void *cls);
417 #if 0 /* keep Emacsens' auto-indent happy */