summaryrefslogtreecommitdiff
path: root/src/block/block.c
blob: 975c0f747bb1a1e828b6543234bc2581f90515cb (plain)
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
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
/*
     This file is part of GNUnet.
     Copyright (C) 2010, 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/>.

     SPDX-License-Identifier: AGPL3.0-or-later
 */

/**
 * @file block/block.c
 * @brief library for data block manipulation
 * @author Christian Grothoff
 */
#include "platform.h"
#include "gnunet_util_lib.h"
#include "gnunet_constants.h"
#include "gnunet_signatures.h"
#include "gnunet_block_lib.h"
#include "gnunet_block_plugin.h"


/**
 * Handle for a plugin.
 */
struct Plugin
{
  /**
   * Name of the shared library.
   */
  char *library_name;

  /**
   * Plugin API.
   */
  struct GNUNET_BLOCK_PluginFunctions *api;
};


/**
 * Handle to an initialized block library.
 */
struct GNUNET_BLOCK_Context
{
  /**
   * Array of our plugins.
   */
  struct Plugin **plugins;

  /**
   * Size of the 'plugins' array.
   */
  unsigned int num_plugins;

  /**
   * Our configuration.
   */
  const struct GNUNET_CONFIGURATION_Handle *cfg;
};


/**
 * Mingle hash with the mingle_number to produce different bits.
 *
 * @param in original hash code
 * @param mingle_number number for hash permutation
 * @param hc where to store the result.
 */
void
GNUNET_BLOCK_mingle_hash (const struct GNUNET_HashCode *in,
                          uint32_t mingle_number,
                          struct GNUNET_HashCode *hc)
{
  struct GNUNET_HashCode m;

  GNUNET_CRYPTO_hash (&mingle_number,
                      sizeof(uint32_t),
                      &m);
  GNUNET_CRYPTO_hash_xor (&m,
                          in,
                          hc);
}


/**
 * Add a plugin to the list managed by the block library.
 *
 * @param cls the block context
 * @param library_name name of the plugin
 * @param lib_ret the plugin API
 */
static void
add_plugin (void *cls,
            const char *library_name,
            void *lib_ret)
{
  struct GNUNET_BLOCK_Context *ctx = cls;
  struct GNUNET_BLOCK_PluginFunctions *api = lib_ret;
  struct Plugin *plugin;

  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Loading block plugin `%s'\n",
              library_name);
  plugin = GNUNET_new (struct Plugin);
  plugin->api = api;
  plugin->library_name = GNUNET_strdup (library_name);
  GNUNET_array_append (ctx->plugins,
                       ctx->num_plugins,
                       plugin);
}


/**
 * Create a block context.  Loads the block plugins.
 *
 * @param cfg configuration to use
 * @return NULL on error
 */
struct GNUNET_BLOCK_Context *
GNUNET_BLOCK_context_create (const struct GNUNET_CONFIGURATION_Handle *cfg)
{
  struct GNUNET_BLOCK_Context *ctx;

  ctx = GNUNET_new (struct GNUNET_BLOCK_Context);
  ctx->cfg = cfg;
  GNUNET_PLUGIN_load_all_in_context (GNUNET_OS_project_data_default (),
                                     "libgnunet_plugin_block_",
                                     (void *) cfg,
                                     &add_plugin,
                                     ctx);
  return ctx;
}


/**
 * Destroy the block context.
 *
 * @param ctx context to destroy
 */
void
GNUNET_BLOCK_context_destroy (struct GNUNET_BLOCK_Context *ctx)
{
  struct Plugin *plugin;

  for (unsigned int i = 0; i < ctx->num_plugins; i++)
  {
    plugin = ctx->plugins[i];
    GNUNET_break (NULL ==
                  GNUNET_PLUGIN_unload (plugin->library_name,
                                        plugin->api));
    GNUNET_free (plugin->library_name);
    GNUNET_free (plugin);
  }
  GNUNET_free (ctx->plugins);
  GNUNET_free (ctx);
}


/**
 * 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
 */
int
GNUNET_BLOCK_group_serialize (struct GNUNET_BLOCK_Group *bg,
                              uint32_t *nonce,
                              void **raw_data,
                              size_t *raw_data_size)
{
  *nonce = 0;
  *raw_data = NULL;
  *raw_data_size = 0;
  if (NULL == bg)
    return GNUNET_NO;
  if (NULL == bg->serialize_cb)
    return GNUNET_NO;
  return bg->serialize_cb (bg,
                           nonce,
                           raw_data,
                           raw_data_size);
}


/**
 * Destroy resources used by a block group.
 *
 * @param bg group to destroy, NULL is allowed
 */
void
GNUNET_BLOCK_group_destroy (struct GNUNET_BLOCK_Group *bg)
{
  if (NULL == bg)
    return;
  bg->destroy_cb (bg);
}


/**
 * Try merging two block groups.  Afterwards, @a bg1 should remain
 * valid and contain the rules from both @a bg1 and @bg2, and
 * @a bg2 should be destroyed (as part of this call).  The latter
 * should happen even if merging is not supported.
 *
 * @param[in,out] bg1 first group to merge, is updated
 * @param bg2 second group to merge, is destroyed
 * @return #GNUNET_OK on success,
 *         #GNUNET_NO if merge failed due to different nonce
 *         #GNUNET_SYSERR if merging is not supported
 */
int
GNUNET_BLOCK_group_merge (struct GNUNET_BLOCK_Group *bg1,
                          struct GNUNET_BLOCK_Group *bg2)
{
  int ret;

  if (NULL == bg2)
    return GNUNET_OK;
  if (NULL == bg1)
  {
    bg2->destroy_cb (bg2);
    return GNUNET_OK;
  }
  if (NULL == bg1->merge_cb)
    return GNUNET_SYSERR;
  GNUNET_assert (bg1->merge_cb == bg1->merge_cb);
  ret = bg1->merge_cb (bg1,
                       bg2);
  bg2->destroy_cb (bg2);
  return ret;
}


/**
 * Find a plugin for the given type.
 *
 * @param ctx context to search
 * @param type type to look for
 * @return NULL if no matching plugin exists
 */
static struct GNUNET_BLOCK_PluginFunctions *
find_plugin (struct GNUNET_BLOCK_Context *ctx,
             enum GNUNET_BLOCK_Type type)
{
  struct Plugin *plugin;
  unsigned int j;

  for (unsigned i = 0; i < ctx->num_plugins; i++)
  {
    plugin = ctx->plugins[i];
    j = 0;
    while (0 != (plugin->api->types[j]))
    {
      if (type == plugin->api->types[j])
        return plugin->api;
      j++;
    }
  }
  return NULL;
}


/**
 * 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
 * @return block group handle, NULL if block groups are not supported
 *         by this @a type of block (this is not an error)
 */
struct GNUNET_BLOCK_Group *
GNUNET_BLOCK_group_create (struct GNUNET_BLOCK_Context *ctx,
                           enum GNUNET_BLOCK_Type type,
                           uint32_t nonce,
                           const void *raw_data,
                           size_t raw_data_size,
                           ...)
{
  struct GNUNET_BLOCK_PluginFunctions *plugin;
  struct GNUNET_BLOCK_Group *bg;
  va_list ap;

  plugin = find_plugin (ctx,
                        type);
  if (NULL == plugin)
    return NULL;
  if (NULL == plugin->create_group)
    return NULL;
  va_start (ap,
            raw_data_size);
  bg = plugin->create_group (plugin->cls,
                             type,
                             nonce,
                             raw_data,
                             raw_data_size,
                             ap);
  va_end (ap);
  return bg;
}


/**
 * Function called to validate a reply or a request.  For
 * request evaluation, simply pass "NULL" for the 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 ctx block contxt
 * @param type block type
 * @param block block group to use
 * @param eo control flags
 * @param query original query (hash)
 * @param xquery extended 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
 */
enum GNUNET_BLOCK_EvaluationResult
GNUNET_BLOCK_evaluate (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)
{
  struct GNUNET_BLOCK_PluginFunctions *plugin = find_plugin (ctx,
                                                             type);

  if (NULL == plugin)
    return GNUNET_BLOCK_EVALUATION_TYPE_NOT_SUPPORTED;
  return plugin->evaluate (plugin->cls,
                           ctx,
                           type,
                           group,
                           eo,
                           query,
                           xquery,
                           xquery_size,
                           reply_block,
                           reply_block_size);
}


/**
 * Function called to obtain the key for a block.
 *
 * @param ctx block context
 * @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_OK on success, #GNUNET_SYSERR if type not supported
 *         (or if extracting a key from a block of this type does not work)
 */
int
GNUNET_BLOCK_get_key (struct GNUNET_BLOCK_Context *ctx,
                      enum GNUNET_BLOCK_Type type,
                      const void *block,
                      size_t block_size,
                      struct GNUNET_HashCode *key)
{
  struct GNUNET_BLOCK_PluginFunctions *plugin = find_plugin (ctx,
                                                             type);

  if (plugin == NULL)
    return GNUNET_BLOCK_EVALUATION_TYPE_NOT_SUPPORTED;
  return plugin->get_key (plugin->cls,
                          type,
                          block,
                          block_size,
                          key);
}


/**
 * Update block group to filter out the given results.  Note that the
 * use of a hash for seen results implies that the caller magically
 * knows how the specific block engine hashes for filtering
 * duplicates, so this API may not always apply.
 *
 * @param bf_mutator mutation value to use
 * @param seen_results results already seen
 * @param seen_results_count number of entries in @a seen_results
 * @return #GNUNET_SYSERR if not supported, #GNUNET_OK on success
 */
int
GNUNET_BLOCK_group_set_seen (struct GNUNET_BLOCK_Group *bg,
                             const struct GNUNET_HashCode *seen_results,
                             unsigned int seen_results_count)
{
  if (NULL == bg)
    return GNUNET_OK;
  if (NULL == bg->mark_seen_cb)
    return GNUNET_SYSERR;
  bg->mark_seen_cb (bg,
                    seen_results,
                    seen_results_count);
  return GNUNET_OK;
}


/* end of block.c */