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3 (C) 2004, 2005, 2006, 2008, 2009, 2011 Christian Grothoff (and other contributing authors)
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22 * @file include/gnunet_dht_service.h
23 * @brief API to the DHT service
24 * @author Christian Grothoff
27 #ifndef GNUNET_DHT_SERVICE_H
28 #define GNUNET_DHT_SERVICE_H
30 #include "gnunet_util_lib.h"
31 #include "gnunet_block_lib.h"
32 #include "gnunet_hello_lib.h"
37 #if 0 /* keep Emacsens' auto-indent happy */
44 * Default republication frequency for stored data in the DHT.
46 #define GNUNET_DHT_DEFAULT_REPUBLISH_FREQUENCY GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_MINUTES, 60)
51 * Connection to the DHT service.
53 struct GNUNET_DHT_Handle;
56 * Handle to control a get operation.
58 struct GNUNET_DHT_GetHandle;
61 * Handle to control a find peer operation.
63 struct GNUNET_DHT_FindPeerHandle;
67 * Options for routing.
69 enum GNUNET_DHT_RouteOption
72 * Default. Do nothing special.
74 GNUNET_DHT_RO_NONE = 0,
77 * Each peer along the way should look at 'enc' (otherwise
78 * only the k-peers closest to the key should look at it).
80 GNUNET_DHT_RO_DEMULTIPLEX_EVERYWHERE = 1,
83 * We should keep track of the route that the message
84 * took in the P2P network.
86 GNUNET_DHT_RO_RECORD_ROUTE = 2,
89 * This is a 'FIND-PEER' request, so approximate results are fine.
91 GNUNET_DHT_RO_FIND_PEER = 4,
94 * Possible message option for query key randomization.
96 GNUNET_DHT_RO_BART = 8
101 * Initialize the connection with the DHT service.
103 * @param cfg configuration to use
104 * @param ht_len size of the internal hash table to use for
105 * processing multiple GET/FIND requests in parallel
106 * @return NULL on error
108 struct GNUNET_DHT_Handle *
109 GNUNET_DHT_connect (const struct GNUNET_CONFIGURATION_Handle *cfg,
110 unsigned int ht_len);
114 * Shutdown connection with the DHT service.
116 * @param handle connection to shut down
119 GNUNET_DHT_disconnect (struct GNUNET_DHT_Handle *handle);
122 /* *************** Standard API: get and put ******************* */
126 * Opaque handle to cancel a PUT operation.
128 struct GNUNET_DHT_PutHandle;
132 * Type of a PUT continuation. You must not call
133 * "GNUNET_DHT_disconnect" in this continuation.
136 * @param success GNUNET_OK if the PUT was transmitted,
137 * GNUNET_NO on timeout,
138 * GNUNET_SYSERR on disconnect from service
139 * after the PUT message was transmitted
140 * (so we don't know if it was received or not)
142 typedef void (*GNUNET_DHT_PutContinuation)(void *cls,
147 * Perform a PUT operation storing data in the DHT.
149 * @param handle handle to DHT service
150 * @param key the key to store under
151 * @param desired_replication_level estimate of how many
152 * nearest peers this request should reach
153 * @param options routing options for this message
154 * @param type type of the value
155 * @param size number of bytes in data; must be less than 64k
156 * @param data the data to store
157 * @param exp desired expiration time for the value
158 * @param timeout how long to wait for transmission of this request
159 * @param cont continuation to call when done (transmitting request to service)
160 * You must not call "GNUNET_DHT_disconnect" in this continuation
161 * @param cont_cls closure for cont
162 * @return handle to cancel the "PUT" operation, NULL on error
165 struct GNUNET_DHT_PutHandle *
166 GNUNET_DHT_put (struct GNUNET_DHT_Handle *handle,
167 const struct GNUNET_HashCode * key,
168 uint32_t desired_replication_level,
169 enum GNUNET_DHT_RouteOption options,
170 enum GNUNET_BLOCK_Type type,
171 size_t size, const void *data,
172 struct GNUNET_TIME_Absolute exp,
173 struct GNUNET_TIME_Relative timeout,
174 GNUNET_DHT_PutContinuation cont,
179 * Cancels a DHT PUT operation. Note that the PUT request may still
180 * go out over the network (we can't stop that); However, if the PUT
181 * has not yet been sent to the service, cancelling the PUT will stop
182 * this from happening (but there is no way for the user of this API
183 * to tell if that is the case). The only use for this API is to
184 * prevent a later call to 'cont' from "GNUNET_DHT_put" (i.e. because
185 * the system is shutting down).
187 * @param ph put operation to cancel ('cont' will no longer be called)
190 GNUNET_DHT_put_cancel (struct GNUNET_DHT_PutHandle *ph);
194 * Iterator called on each result obtained for a DHT
195 * operation that expects a reply
198 * @param exp when will this value expire
199 * @param key key of the result
200 * @param get_path peers on reply path (or NULL if not recorded)
201 * [0] = datastore's first neighbor, [length - 1] = local peer
202 * @param get_path_length number of entries in get_path
203 * @param put_path peers on the PUT path (or NULL if not recorded)
204 * [0] = origin, [length - 1] = datastore
205 * @param put_path_length number of entries in get_path
206 * @param type type of the result
207 * @param size number of bytes in data
208 * @param data pointer to the result data
210 typedef void (*GNUNET_DHT_GetIterator) (void *cls,
211 struct GNUNET_TIME_Absolute exp,
212 const struct GNUNET_HashCode * key,
213 const struct GNUNET_PeerIdentity *
214 get_path, unsigned int get_path_length,
215 const struct GNUNET_PeerIdentity *
216 put_path, unsigned int put_path_length,
217 enum GNUNET_BLOCK_Type type,
218 size_t size, const void *data);
223 * Perform an asynchronous GET operation on the DHT identified. See
224 * also "GNUNET_BLOCK_evaluate".
226 * @param handle handle to the DHT service
227 * @param type expected type of the response object
228 * @param key the key to look up
229 * @param desired_replication_level estimate of how many
230 nearest peers this request should reach
231 * @param options routing options for this message
232 * @param xquery extended query data (can be NULL, depending on type)
233 * @param xquery_size number of bytes in xquery
234 * @param iter function to call on each result
235 * @param iter_cls closure for iter
237 * @return handle to stop the async get
239 struct GNUNET_DHT_GetHandle *
240 GNUNET_DHT_get_start (struct GNUNET_DHT_Handle *handle,
241 enum GNUNET_BLOCK_Type type,
242 const struct GNUNET_HashCode *key,
243 uint32_t desired_replication_level,
244 enum GNUNET_DHT_RouteOption options,
245 const void *xquery, size_t xquery_size,
246 GNUNET_DHT_GetIterator iter, void *iter_cls);
250 * Tell the DHT not to return any of the following known results
253 * @param get_handle get operation for which results should be filtered
254 * @param num_results number of results to be blocked that are
255 * provided in this call (size of the 'results' array)
256 * @param results array of hash codes over the 'data' of the results
260 GNUNET_DHT_get_filter_known_results (struct GNUNET_DHT_GetHandle *get_handle,
261 unsigned int num_results,
262 const struct GNUNET_HashCode *results);
265 * Stop async DHT-get. Frees associated resources.
267 * @param get_handle GET operation to stop.
269 * On return get_handle will no longer be valid, caller
270 * must not use again!!!
273 GNUNET_DHT_get_stop (struct GNUNET_DHT_GetHandle *get_handle);
276 /* *************** Extended API: monitor ******************* */
279 * Handle to monitor requests
281 struct GNUNET_DHT_MonitorHandle;
284 * Callback called on each GET request going through the DHT.
286 * @param cls Closure.
287 * @param options Options, for instance RecordRoute, DemultiplexEverywhere.
288 * @param type The type of data in the request.
289 * @param hop_count Hop count so far.
290 * @param path_length number of entries in path (or 0 if not recorded).
291 * @param path peers on the GET path (or NULL if not recorded).
292 * @param desired_replication_level Desired replication level.
293 * @param key Key of the requested data.
295 typedef void (*GNUNET_DHT_MonitorGetCB) (void *cls,
296 enum GNUNET_DHT_RouteOption options,
297 enum GNUNET_BLOCK_Type type,
299 uint32_t desired_replication_level,
300 unsigned int path_length,
301 const struct GNUNET_PeerIdentity *path,
302 const struct GNUNET_HashCode * key);
305 * Callback called on each GET reply going through the DHT.
307 * @param cls Closure.
308 * @param type The type of data in the result.
309 * @param get_path Peers on GET path (or NULL if not recorded).
310 * @param get_path_length number of entries in get_path.
311 * @param put_path peers on the PUT path (or NULL if not recorded).
312 * @param put_path_length number of entries in get_path.
313 * @param exp Expiration time of the data.
314 * @param key Key of the data.
315 * @param data Pointer to the result data.
316 * @param size Number of bytes in data.
318 typedef void (*GNUNET_DHT_MonitorGetRespCB) (void *cls,
319 enum GNUNET_BLOCK_Type type,
320 const struct GNUNET_PeerIdentity
322 unsigned int get_path_length,
323 const struct GNUNET_PeerIdentity
325 unsigned int put_path_length,
326 struct GNUNET_TIME_Absolute exp,
327 const struct GNUNET_HashCode * key,
332 * Callback called on each PUT request going through the DHT.
334 * @param cls Closure.
335 * @param options Options, for instance RecordRoute, DemultiplexEverywhere.
336 * @param type The type of data in the request.
337 * @param hop_count Hop count so far.
338 * @param path_length number of entries in path (or 0 if not recorded).
339 * @param path peers on the PUT path (or NULL if not recorded).
340 * @param desired_replication_level Desired replication level.
341 * @param exp Expiration time of the data.
342 * @param key Key under which data is to be stored.
343 * @param data Pointer to the data carried.
344 * @param size Number of bytes in data.
346 typedef void (*GNUNET_DHT_MonitorPutCB) (void *cls,
347 enum GNUNET_DHT_RouteOption options,
348 enum GNUNET_BLOCK_Type type,
350 uint32_t desired_replication_level,
351 unsigned int path_length,
352 const struct GNUNET_PeerIdentity *path,
353 struct GNUNET_TIME_Absolute exp,
354 const struct GNUNET_HashCode * key,
359 * Start monitoring the local DHT service.
361 * @param handle Handle to the DHT service.
362 * @param type Type of blocks that are of interest.
363 * @param key Key of data of interest, NULL for all.
364 * @param get_cb Callback to process monitored get messages.
365 * @param get_resp_cb Callback to process monitored get response messages.
366 * @param put_cb Callback to process monitored put messages.
367 * @param cb_cls Closure for cb.
369 * @return Handle to stop monitoring.
371 struct GNUNET_DHT_MonitorHandle *
372 GNUNET_DHT_monitor_start (struct GNUNET_DHT_Handle *handle,
373 enum GNUNET_BLOCK_Type type,
374 const struct GNUNET_HashCode *key,
375 GNUNET_DHT_MonitorGetCB get_cb,
376 GNUNET_DHT_MonitorGetRespCB get_resp_cb,
377 GNUNET_DHT_MonitorPutCB put_cb,
384 * @param handle The handle to the monitor request returned by monitor_start.
386 * On return handle will no longer be valid, caller must not use again!!!
389 GNUNET_DHT_monitor_stop (struct GNUNET_DHT_MonitorHandle *handle);
392 #if 0 /* keep Emacsens' auto-indent happy */
401 /* gnunet_dht_service.h */