aboutsummaryrefslogtreecommitdiff
path: root/src/include/gnunet_block_plugin.h
blob: 1fa7ccf8bcbe7eb2740f29cff8805777a148d9dc (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
/*
     This file is part of GNUnet
     Copyright (C) 2010, 2013, 2017, 2021, 2022 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 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 enum GNUNET_GenericReturnValue
(*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 enum GNUNET_GenericReturnValue
(*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 query.
 *
 * @param cls closure
 * @param type block type
 * @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
 * @return #GNUNET_OK if the query is fine, #GNUNET_NO if not
 */
typedef enum GNUNET_GenericReturnValue
(*GNUNET_BLOCK_QueryEvaluationFunction)(void *cls,
                                        enum GNUNET_BLOCK_Type type,
                                        const struct GNUNET_HashCode *query,
                                        const void *xquery,
                                        size_t xquery_size);


/**
 * Function called to validate a @a block for storage.
 *
 * @param cls closure
 * @param type block type
 * @param block block data to validate
 * @param block_size number of bytes in @a block
 * @return #GNUNET_OK if the @a block is fine, #GNUNET_NO if not, #GNUNET_SYSERR if the @a type is not supported
 */
typedef enum GNUNET_GenericReturnValue
(*GNUNET_BLOCK_BlockEvaluationFunction)(void *cls,
                                        enum GNUNET_BLOCK_Type type,
                                        const void *block,
                                        size_t block_size);


/**
 * Function called to validate a reply to a request.  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 GetKeyFunction and the
 * BlockEvaluationFunction.
 *
 * @param cls closure
 * @param type block type
 * @param group which block group to use for 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_ReplyEvaluationResult
(*GNUNET_BLOCK_ReplyEvaluationFunction)(void *cls,
                                        enum GNUNET_BLOCK_Type type,
                                        struct GNUNET_BLOCK_Group *group,
                                        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 @a key for a block.
 * If the @a block is malformed, the function should
 * zero-out @a key and return #GNUNET_OK.
 *
 * @param cls closure
 * @param type block type
 * @param block block to get the @a key for
 * @param block_size number of bytes in @a block
 * @param[out] key set to the key (query) for the given block
 * @return #GNUNET_YES on success,
 *         #GNUNET_NO if extracting a key for this @a type does not work
 *         #GNUNET_SYSERR if @a type not supported
 */
typedef enum GNUNET_GenericReturnValue
(*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;

  /**
   * 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;

  /**
   * Check that a query is well-formed.
   */
  GNUNET_BLOCK_QueryEvaluationFunction check_query;

  /**
   * Check that a block is well-formed.
   */
  GNUNET_BLOCK_BlockEvaluationFunction check_block;

  /**
   * Check that a reply block matches a query.
   */
  GNUNET_BLOCK_ReplyEvaluationFunction check_reply;  

};

#endif

/** @} */  /* end of group */