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- /*
- This file is part of GNUnet
- Copyright (C) 2004-2013, 2016 GNUnet e.V.
- GNUnet is free software: you can redistribute it and/or modify it
- under the terms of the GNU Affero General Public License as published
- by the Free Software Foundation, either version 3 of the License,
- or (at your option) any later version.
- GNUnet is distributed in the hope that it will be useful, but
- WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- Affero General Public License for more details.
-
- You should have received a copy of the GNU Affero General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>.
- SPDX-License-Identifier: AGPL3.0-or-later
- */
- /**
- * @author Christian Grothoff
- *
- * @file
- * API to the DHT service
- *
- * @defgroup dht DHT service
- * Distributed Hash Table
- *
- * @see [Documentation](https://gnunet.org/developer-handbook-dht)
- *
- * @{
- */
- #ifndef GNUNET_DHT_SERVICE_H
- #define GNUNET_DHT_SERVICE_H
- #include "gnunet_util_lib.h"
- #include "gnunet_block_lib.h"
- #include "gnunet_hello_lib.h"
- #ifdef __cplusplus
- extern "C"
- {
- #if 0 /* keep Emacsens' auto-indent happy */
- }
- #endif
- #endif
- /**
- * Default republication frequency for stored data in the DHT.
- */
- #define GNUNET_DHT_DEFAULT_REPUBLISH_FREQUENCY GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_MINUTES, 60)
- /**
- * Connection to the DHT service.
- */
- struct GNUNET_DHT_Handle;
- /**
- * Handle to control a get operation.
- */
- struct GNUNET_DHT_GetHandle;
- /**
- * Handle to control a find peer operation.
- */
- struct GNUNET_DHT_FindPeerHandle;
- /**
- * Options for routing.
- */
- enum GNUNET_DHT_RouteOption
- {
- /**
- * Default. Do nothing special.
- */
- GNUNET_DHT_RO_NONE = 0,
- /**
- * Each peer along the way should look at 'enc' (otherwise
- * only the k-peers closest to the key should look at it).
- */
- GNUNET_DHT_RO_DEMULTIPLEX_EVERYWHERE = 1,
- /**
- * We should keep track of the route that the message
- * took in the P2P network.
- */
- GNUNET_DHT_RO_RECORD_ROUTE = 2,
- /**
- * This is a 'FIND-PEER' request, so approximate results are fine.
- */
- GNUNET_DHT_RO_FIND_PEER = 4,
- /**
- * Possible message option for query key randomization.
- */
- GNUNET_DHT_RO_BART = 8,
- /**
- * Flag given to monitors if this was the last hop for a GET/PUT.
- */
- GNUNET_DHT_RO_LAST_HOP = 16
- };
- /**
- * Initialize the connection with the DHT service.
- *
- * @param cfg configuration to use
- * @param ht_len size of the internal hash table to use for
- * processing multiple GET/FIND requests in parallel
- * @return NULL on error
- */
- struct GNUNET_DHT_Handle *
- GNUNET_DHT_connect (const struct GNUNET_CONFIGURATION_Handle *cfg,
- unsigned int ht_len);
- /**
- * Shutdown connection with the DHT service.
- *
- * @param handle connection to shut down
- */
- void
- GNUNET_DHT_disconnect (struct GNUNET_DHT_Handle *handle);
- /* *************** Standard API: get and put ******************* */
- /**
- * Opaque handle to cancel a PUT operation.
- */
- struct GNUNET_DHT_PutHandle;
- /**
- * Perform a PUT operation storing data in the DHT.
- *
- * @param handle handle to DHT service
- * @param key the key to store under
- * @param desired_replication_level estimate of how many
- * nearest peers this request should reach
- * @param options routing options for this message
- * @param type type of the value
- * @param size number of bytes in @a data; must be less than 64k
- * @param data the data to store
- * @param exp desired expiration time for the value
- * @param cont continuation to call when done (transmitting request to service)
- * You must not call #GNUNET_DHT_disconnect in this continuation
- * @param cont_cls closure for @a cont
- * @return handle to cancel the "PUT" operation, NULL on error
- * (size too big)
- */
- struct GNUNET_DHT_PutHandle *
- GNUNET_DHT_put (struct GNUNET_DHT_Handle *handle,
- const struct GNUNET_HashCode *key,
- uint32_t desired_replication_level,
- enum GNUNET_DHT_RouteOption options,
- enum GNUNET_BLOCK_Type type,
- size_t size,
- const void *data,
- struct GNUNET_TIME_Absolute exp,
- GNUNET_SCHEDULER_TaskCallback cont,
- void *cont_cls);
- /**
- * Cancels a DHT PUT operation. Note that the PUT request may still
- * go out over the network (we can't stop that); However, if the PUT
- * has not yet been sent to the service, cancelling the PUT will stop
- * this from happening (but there is no way for the user of this API
- * to tell if that is the case). The only use for this API is to
- * prevent a later call to 'cont' from #GNUNET_DHT_put (i.e. because
- * the system is shutting down).
- *
- * @param ph put operation to cancel ('cont' will no longer be called)
- */
- void
- GNUNET_DHT_put_cancel (struct GNUNET_DHT_PutHandle *ph);
- /**
- * Iterator called on each result obtained for a DHT
- * operation that expects a reply
- *
- * @param cls closure
- * @param exp when will this value expire
- * @param key key of the result
- * @param get_path peers on reply path (or NULL if not recorded)
- * [0] = datastore's first neighbor, [length - 1] = local peer
- * @param get_path_length number of entries in @a get_path
- * @param put_path peers on the PUT path (or NULL if not recorded)
- * [0] = origin, [length - 1] = datastore
- * @param put_path_length number of entries in @a put_path
- * @param type type of the result
- * @param size number of bytes in @a data
- * @param data pointer to the result data
- */
- typedef void
- (*GNUNET_DHT_GetIterator) (void *cls,
- struct GNUNET_TIME_Absolute exp,
- const struct GNUNET_HashCode *key,
- const struct GNUNET_PeerIdentity *get_path,
- unsigned int get_path_length,
- const struct GNUNET_PeerIdentity *put_path,
- unsigned int put_path_length,
- enum GNUNET_BLOCK_Type type,
- size_t size,
- const void *data);
- /**
- * Perform an asynchronous GET operation on the DHT identified. See
- * also #GNUNET_BLOCK_evaluate.
- *
- * @param handle handle to the DHT service
- * @param type expected type of the response object
- * @param key the key to look up
- * @param desired_replication_level estimate of how many
- nearest peers this request should reach
- * @param options routing options for this message
- * @param xquery extended query data (can be NULL, depending on type)
- * @param xquery_size number of bytes in @a xquery
- * @param iter function to call on each result
- * @param iter_cls closure for @a iter
- * @return handle to stop the async get
- */
- struct GNUNET_DHT_GetHandle *
- GNUNET_DHT_get_start (struct GNUNET_DHT_Handle *handle,
- enum GNUNET_BLOCK_Type type,
- const struct GNUNET_HashCode *key,
- uint32_t desired_replication_level,
- enum GNUNET_DHT_RouteOption options,
- const void *xquery,
- size_t xquery_size,
- GNUNET_DHT_GetIterator iter,
- void *iter_cls);
- /**
- * Tell the DHT not to return any of the following known results
- * to this client.
- *
- * @param get_handle get operation for which results should be filtered
- * @param num_results number of results to be blocked that are
- * provided in this call (size of the @a results array)
- * @param results array of hash codes over the `data` of the results
- * to be blocked
- */
- void
- GNUNET_DHT_get_filter_known_results (struct GNUNET_DHT_GetHandle *get_handle,
- unsigned int num_results,
- const struct GNUNET_HashCode *results);
- /**
- * Stop async DHT-get. Frees associated resources.
- *
- * @param get_handle GET operation to stop.
- */
- void
- GNUNET_DHT_get_stop (struct GNUNET_DHT_GetHandle *get_handle);
- /* *************** Extended API: monitor ******************* */
- /**
- * Handle to monitor requests
- */
- struct GNUNET_DHT_MonitorHandle;
- /**
- * Callback called on each GET request going through the DHT.
- *
- * @param cls Closure.
- * @param options Options, for instance RecordRoute, DemultiplexEverywhere.
- * @param type The type of data in the request.
- * @param hop_count Hop count so far.
- * @param path_length number of entries in @a path (or 0 if not recorded).
- * @param path peers on the GET path (or NULL if not recorded).
- * @param desired_replication_level Desired replication level.
- * @param key Key of the requested data.
- */
- typedef void
- (*GNUNET_DHT_MonitorGetCB) (void *cls,
- enum GNUNET_DHT_RouteOption options,
- enum GNUNET_BLOCK_Type type,
- uint32_t hop_count,
- uint32_t desired_replication_level,
- unsigned int path_length,
- const struct GNUNET_PeerIdentity *path,
- const struct GNUNET_HashCode *key);
- /**
- * Callback called on each GET reply going through the DHT.
- *
- * @param cls Closure.
- * @param type The type of data in the result.
- * @param get_path Peers on GET path (or NULL if not recorded).
- * @param get_path_length number of entries in @a get_path.
- * @param put_path peers on the PUT path (or NULL if not recorded).
- * @param put_path_length number of entries in @a get_path.
- * @param exp Expiration time of the data.
- * @param key Key of the data.
- * @param data Pointer to the result data.
- * @param size Number of bytes in @a data.
- */
- typedef void
- (*GNUNET_DHT_MonitorGetRespCB) (void *cls,
- enum GNUNET_BLOCK_Type type,
- const struct GNUNET_PeerIdentity *get_path,
- unsigned int get_path_length,
- const struct GNUNET_PeerIdentity *put_path,
- unsigned int put_path_length,
- struct GNUNET_TIME_Absolute exp,
- const struct GNUNET_HashCode *key,
- const void *data,
- size_t size);
- /**
- * Callback called on each PUT request going through the DHT.
- *
- * @param cls Closure.
- * @param options Options, for instance RecordRoute, DemultiplexEverywhere.
- * @param type The type of data in the request.
- * @param hop_count Hop count so far.
- * @param path_length number of entries in @a path (or 0 if not recorded).
- * @param path peers on the PUT path (or NULL if not recorded).
- * @param desired_replication_level Desired replication level.
- * @param exp Expiration time of the data.
- * @param key Key under which data is to be stored.
- * @param data Pointer to the data carried.
- * @param size Number of bytes in @a data.
- */
- typedef void
- (*GNUNET_DHT_MonitorPutCB) (void *cls,
- enum GNUNET_DHT_RouteOption options,
- enum GNUNET_BLOCK_Type type,
- uint32_t hop_count,
- uint32_t desired_replication_level,
- unsigned int path_length,
- const struct GNUNET_PeerIdentity *path,
- struct GNUNET_TIME_Absolute exp,
- const struct GNUNET_HashCode *key,
- const void *data,
- size_t size);
- /**
- * Start monitoring the local DHT service.
- *
- * @param handle Handle to the DHT service.
- * @param type Type of blocks that are of interest.
- * @param key Key of data of interest, NULL for all.
- * @param get_cb Callback to process monitored get messages.
- * @param get_resp_cb Callback to process monitored get response messages.
- * @param put_cb Callback to process monitored put messages.
- * @param cb_cls Closure for callbacks
- * @return Handle to stop monitoring.
- */
- struct GNUNET_DHT_MonitorHandle *
- GNUNET_DHT_monitor_start (struct GNUNET_DHT_Handle *handle,
- enum GNUNET_BLOCK_Type type,
- const struct GNUNET_HashCode *key,
- GNUNET_DHT_MonitorGetCB get_cb,
- GNUNET_DHT_MonitorGetRespCB get_resp_cb,
- GNUNET_DHT_MonitorPutCB put_cb,
- void *cb_cls);
- /**
- * Stop monitoring.
- * On return handle will no longer be valid, caller must not use it anymore.
- *
- * @param handle The handle to the monitor request returned by
- * #GNUNET_DHT_monitor_start().
- */
- void
- GNUNET_DHT_monitor_stop (struct GNUNET_DHT_MonitorHandle *handle);
- #if 0 /* keep Emacsens' auto-indent happy */
- {
- #endif
- #ifdef __cplusplus
- }
- #endif
- #endif
- /** @} */ /* end of group dht */
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