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/*
This file is part of GNUnet
Copyright (C) 2010,2013,2017 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/>.
*/
/**
* @author Christian Grothoff
*
* @file
* API for block plugins.
*
* @defgroup block-plugin Block plugin API
* To be implemented by applications storing data in the DHT.
*
* Each block plugin must conform to the API specified by this header.
*
* @{
*/
#ifndef PLUGIN_BLOCK_H
#define PLUGIN_BLOCK_H
#include "gnunet_util_lib.h"
#include "gnunet_block_lib.h"
/**
* Mark elements as "seen" using a hash of the element. Not supported
* by all block plugins.
*
* @param bg group to update
* @param seen_results results already seen
* @param seen_results_count number of entries in @a seen_results
*/
typedef void
(*GNUNET_BLOCK_GroupMarkSeenFunction)(struct GNUNET_BLOCK_Group *bg,
const struct GNUNET_HashCode *seen_results,
unsigned int seen_results_count);
/**
* Merge two groups, if possible. Not supported by all block plugins,
* can also fail if the nonces were different.
*
* @param bg1 group to update
* @param bg2 group to merge into @a bg1
* @return #GNUNET_OK on success, #GNUNET_NO if the nonces were different and thus
* we failed.
*/
typedef int
(*GNUNET_BLOCK_GroupMergeFunction)(struct GNUNET_BLOCK_Group *bg1,
const struct GNUNET_BLOCK_Group *bg2);
/**
* Serialize state of a block group.
*
* @param bg group to serialize
* @param[out] nonce set to the nonce of the @a bg
* @param[out] raw_data set to the serialized state
* @param[out] raw_data_size set to the number of bytes in @a raw_data
* @return #GNUNET_OK on success, #GNUNET_NO if serialization is not
* supported, #GNUNET_SYSERR on error
*/
typedef int
(*GNUNET_BLOCK_GroupSerializeFunction)(struct GNUNET_BLOCK_Group *bg,
uint32_t *nonce,
void **raw_data,
size_t *raw_data_size);
/**
* Destroy resources used by a block group.
*
* @param bg group to destroy, NULL is allowed
*/
typedef void
(*GNUNET_BLOCK_GroupDestroyFunction)(struct GNUNET_BLOCK_Group *bg);
/**
* Block group data. The plugin must initialize the callbacks
* and can use the @e internal_cls as it likes.
*/
struct GNUNET_BLOCK_Group
{
/**
* Context owning the block group. Set by the main block library.
*/
struct GNUENT_BLOCK_Context *ctx;
/**
* Type for the block group. Set by the main block library.
*/
enum GNUNET_BLOCK_Type type;
/**
* Serialize the block group data, can be NULL if
* not supported.
*/
GNUNET_BLOCK_GroupSerializeFunction serialize_cb;
/**
* Function to call to mark elements as seen in the group.
* Can be NULL if not supported.
*/
GNUNET_BLOCK_GroupMarkSeenFunction mark_seen_cb;
/**
* Function to call to merge two groups.
* Can be NULL if not supported.
*/
GNUNET_BLOCK_GroupMergeFunction merge_cb;
/**
* Function to call to destroy the block group.
* Must not be NULL.
*/
GNUNET_BLOCK_GroupDestroyFunction destroy_cb;
/**
* Internal data structure of the plugin.
*/
void *internal_cls;
};
/**
* Create a new block group.
*
* @param ctx block context in which the block group is created
* @param type type of the block for which we are creating the group
* @param nonce random value used to seed the group creation
* @param raw_data optional serialized prior state of the group, NULL if unavailable/fresh
* @param raw_data_size number of bytes in @a raw_data, 0 if unavailable/fresh
* @param va variable arguments specific to @a type
* @return block group handle, NULL if block groups are not supported
* by this @a type of block (this is not an error)
*/
typedef struct GNUNET_BLOCK_Group *
(*GNUNET_BLOCK_GroupCreateFunction)(void *cls,
enum GNUNET_BLOCK_Type type,
uint32_t nonce,
const void *raw_data,
size_t raw_data_size,
va_list va);
/**
* Function called to validate a reply or a request. For
* request evaluation, simply pass "NULL" for the @a reply_block.
* Note that it is assumed that the reply has already been
* matched to the key (and signatures checked) as it would
* be done with the "get_key" function.
*
* @param cls closure
* @param ctx block context
* @param type block type
* @param group which block group to use for evaluation
* @param eo evaluation options to control evaluation
* @param query original query (hash)
* @param xquery extrended query data (can be NULL, depending on type)
* @param xquery_size number of bytes in @a xquery
* @param reply_block response to validate
* @param reply_block_size number of bytes in @a reply_block
* @return characterization of result
*/
typedef enum GNUNET_BLOCK_EvaluationResult
(*GNUNET_BLOCK_EvaluationFunction) (void *cls,
struct GNUNET_BLOCK_Context *ctx,
enum GNUNET_BLOCK_Type type,
struct GNUNET_BLOCK_Group *group,
enum GNUNET_BLOCK_EvaluationOptions eo,
const struct GNUNET_HashCode *query,
const void *xquery,
size_t xquery_size,
const void *reply_block,
size_t reply_block_size);
/**
* Function called to obtain the key for a block.
*
* @param cls closure
* @param type block type
* @param block block to get the key for
* @param block_size number of bytes in @a block
* @param key set to the key (query) for the given block
* @return #GNUNET_YES on success,
* #GNUNET_NO if the block is malformed
* #GNUNET_SYSERR if type not supported
* (or if extracting a key from a block of this type does not work)
*/
typedef int
(*GNUNET_BLOCK_GetKeyFunction) (void *cls,
enum GNUNET_BLOCK_Type type,
const void *block,
size_t block_size,
struct GNUNET_HashCode *key);
/**
* Each plugin is required to return a pointer to a struct of this
* type as the return value from its entry point.
*/
struct GNUNET_BLOCK_PluginFunctions
{
/**
* Closure for all of the callbacks.
*/
void *cls;
/**
* 0-terminated array of block types supported by this plugin.
*/
const enum GNUNET_BLOCK_Type *types;
/**
* Main function of a block plugin. Allows us to check if a
* block matches a query.
*/
GNUNET_BLOCK_EvaluationFunction evaluate;
/**
* Obtain the key for a given block (if possible).
*/
GNUNET_BLOCK_GetKeyFunction get_key;
/**
* Create a block group to process a bunch of blocks in a shared
* context (i.e. to detect duplicates).
*/
GNUNET_BLOCK_GroupCreateFunction create_group;
};
#endif
/** @} */ /* end of group */
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