/*
This file is part of GNUnet
- (C) 2004, 2005, 2006, 2008, 2009 Christian Grothoff (and other contributing authors)
+ Copyright (C) 2004-2013 GNUnet e.V.
GNUnet is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published
- by the Free Software Foundation; either version 2, or (at your
+ by the Free Software Foundation; either version 3, or (at your
option) any later version.
GNUnet is distributed in the hope that it will be useful, but
You should have received a copy of the GNU General Public License
along with GNUnet; see the file COPYING. If not, write to the
- Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- Boston, MA 02111-1307, USA.
+ Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ Boston, MA 02110-1301, USA.
*/
/**
- * @file include/gnunet_dht_service.h
- * @brief API to the DHT service
* @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"
#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 sched scheduler 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,
- struct GNUNET_SCHEDULER_Handle *sched);
+ unsigned int ht_len);
/**
* Shutdown connection with the DHT service.
*
- * @param h connection to shut down
+ * @param handle connection to shut down
*/
void
-GNUNET_DHT_connect (struct GNUNET_DHT_Handle *h);
+GNUNET_DHT_disconnect (struct GNUNET_DHT_Handle *handle);
+
+
+/* *************** Standard API: get and put ******************* */
/**
- * Handle to control a GET operation.
+ * Opaque handle to cancel a PUT operation.
*/
-struct GNUNET_DHT_GetHandle;
+struct GNUNET_DHT_PutHandle;
+
+
+/**
+ * Type of a PUT continuation. You must not call
+ * #GNUNET_DHT_disconnect in this continuation.
+ *
+ * @param cls closure
+ * @param success #GNUNET_OK if the PUT was transmitted,
+ * #GNUNET_NO on timeout,
+ * #GNUNET_SYSERR on disconnect from service
+ * after the PUT message was transmitted
+ * (so we don't know if it was received or not)
+ */
+typedef void (*GNUNET_DHT_PutContinuation)(void *cls,
+ int success);
+
+
+/**
+ * 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 timeout how long to wait for transmission of this request
+ * @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,
+ struct GNUNET_TIME_Relative timeout,
+ GNUNET_DHT_PutContinuation 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 GET
- * operation.
+ * 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 data
+ * @param size number of bytes in @a data
* @param data pointer to the result data
*/
-typedef void (*GNUNET_DHT_Iterator)(void *cls,
- struct GNUNET_TIME_Absolute exp,
- const GNUNET_HashCode * key,
- uint32_t type,
- uint32_t size,
- const void *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.
+ * 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 iter
+ * @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 *h,
- uint32_t type,
- const GNUNET_HashCode * key,
- GNUNET_DHT_Iterator iter,
- void *iter_cls);
+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 record GET operation to stop.
+ * @param get_handle GET operation to stop.
+ *
+ * On return get_handle will no longer be valid, caller
+ * must not use again!!!
*/
void
-GNUNET_DHT_get_stop (struct GNUNET_DHT_GetHandle *record);
+GNUNET_DHT_get_stop (struct GNUNET_DHT_GetHandle *get_handle);
+/* *************** Extended API: monitor ******************* */
+
/**
- * Perform a PUT operation on the DHT identified by 'table' storing
- * a binding of 'key' to 'value'. The peer does not have to be part
- * of the table (if so, we will attempt to locate a peer that is!)
+ * Handle to monitor requests
+ */
+struct GNUNET_DHT_MonitorHandle;
+
+/**
+ * Callback called on each GET request going through the DHT.
*
- * @param h handle to DHT service
- * @param key the key to store under
- * @param type type of the value
- * @param size number of bytes in 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;
- * reason will be TIMEOUT on error,
- * reason will be PREREQ_DONE on success
- * @param cont_cls closure for cont
- *
- */
-int GNUNET_DHT_put (struct GNUNET_DHT_Handle *h,
- const GNUNET_HashCode * key,
- uint32_t type,
- uint32_t size,
- const char *data,
- struct GNUNET_TIME_Relative exp,
- GNUNET_SCHEDULER_Task cont,
- void *cont_cls);
+ * @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 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 again!!!
+ *
+ * @param handle The handle to the monitor request returned by monitor_start.
+ */
+void
+GNUNET_DHT_monitor_stop (struct GNUNET_DHT_MonitorHandle *handle);
+
+
+#if ENABLE_MALICIOUS
+/**
+ * Type of a Malicious continuation. You must not call
+ * #GNUNET_DHT_disconnect in this continuation.
+ *
+ * @param cls closure
+ * @param success #GNUNET_OK if the set malicious request was transmitted,
+ * #GNUNET_NO on timeout,
+ * #GNUNET_SYSERR on disconnect from service
+ * after the PUT message was transmitted
+ * (so we don't know if it was received or not)
+ */
+typedef void (*GNUNET_DHT_ActMaliciousContinuation)(void *cls,
+ int success);
+
+/**
+ * Turn the DHT service to act malicious
+ *
+ * @param handle the DHT handle
+ * @param action 1 to make the service malicious; 0 to make it benign
+ FIXME: perhaps make this an enum of known malicious behaviors?
+ */
+struct GNUNET_DHT_ActMaliciousHandle *
+GNUNET_DHT_act_malicious (struct GNUNET_DHT_Handle *handle,
+ unsigned int action,
+ GNUNET_DHT_PutContinuation cont,
+ void *cont_cls);
+#endif
#if 0 /* keep Emacsens' auto-indent happy */
}
#endif
+#endif
-#endif
-/* gnunet_dht_service.h */
+/** @} */ /* end of group dht */
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