2 This file is part of GNUnet.
3 (C) 2010 Christian Grothoff (and other contributing authors)
5 GNUnet is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published
7 by the Free Software Foundation; either version 3, or (at your
8 option) any later version.
10 GNUnet is distributed in the hope that it will be useful, but
11 WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with GNUnet; see the file COPYING. If not, write to the
17 Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 Boston, MA 02111-1307, USA.
23 * @brief library for data block manipulation
24 * @author Christian Grothoff
27 #include "gnunet_util_lib.h"
28 #include "gnunet_constants.h"
29 #include "gnunet_signatures.h"
30 #include "gnunet_block_lib.h"
31 #include "gnunet_block_plugin.h"
35 * Handle for a plugin.
40 * Name of the shared library.
47 struct GNUNET_BLOCK_PluginFunctions *api;
52 * Handle to an initialized block library.
54 struct GNUNET_BLOCK_Context
57 * Array of our plugins.
59 struct Plugin **plugins;
62 * Size of the 'plugins' array.
64 unsigned int num_plugins;
69 const struct GNUNET_CONFIGURATION_Handle *cfg;
74 * Mingle hash with the mingle_number to produce different bits.
76 * @param in original hash code
77 * @param mingle_number number for hash permutation
78 * @param hc where to store the result.
81 GNUNET_BLOCK_mingle_hash (const GNUNET_HashCode * in, uint32_t mingle_number,
86 GNUNET_CRYPTO_hash (&mingle_number, sizeof (uint32_t), &m);
87 GNUNET_CRYPTO_hash_xor (&m, in, hc);
92 * Add a plugin to the list managed by the block library.
94 * @param cls the block context
95 * @param library_name name of the plugin
96 * @param lib_ret the plugin API
99 add_plugin (void *cls, const char *library_name, void *lib_ret)
101 struct GNUNET_BLOCK_Context *ctx = cls;
102 struct GNUNET_BLOCK_PluginFunctions *api = lib_ret;
103 struct Plugin *plugin;
105 GNUNET_log (GNUNET_ERROR_TYPE_INFO, _("Loading block plugin `%s'\n"),
107 plugin = GNUNET_malloc (sizeof (struct Plugin));
109 plugin->library_name = GNUNET_strdup (library_name);
110 GNUNET_array_append (ctx->plugins, ctx->num_plugins, plugin);
116 * Create a block context. Loads the block plugins.
118 * @param cfg configuration to use
119 * @return NULL on error
121 struct GNUNET_BLOCK_Context *
122 GNUNET_BLOCK_context_create (const struct GNUNET_CONFIGURATION_Handle *cfg)
124 struct GNUNET_BLOCK_Context *ctx;
126 ctx = GNUNET_malloc (sizeof (struct GNUNET_BLOCK_Context));
128 GNUNET_PLUGIN_load_all ("libgnunet_plugin_block_", NULL, &add_plugin, ctx);
134 * Destroy the block context.
136 * @param ctx context to destroy
139 GNUNET_BLOCK_context_destroy (struct GNUNET_BLOCK_Context *ctx)
142 struct Plugin *plugin;
144 for (i = 0; i < ctx->num_plugins; i++)
146 plugin = ctx->plugins[i];
147 GNUNET_break (NULL ==
148 GNUNET_PLUGIN_unload (plugin->library_name, plugin->api));
149 GNUNET_free (plugin->library_name);
150 GNUNET_free (plugin);
152 GNUNET_free (ctx->plugins);
158 * Find a plugin for the given type.
160 * @param ctx context to search
161 * @param type type to look for
162 * @return NULL if no matching plugin exists
164 static struct GNUNET_BLOCK_PluginFunctions *
165 find_plugin (struct GNUNET_BLOCK_Context *ctx, enum GNUNET_BLOCK_Type type)
167 struct Plugin *plugin;
171 for (i = 0; i < ctx->num_plugins; i++)
173 plugin = ctx->plugins[i];
175 while (0 != (plugin->api->types[j]))
177 if (type == plugin->api->types[j])
187 * Function called to validate a reply or a request. For
188 * request evaluation, simply pass "NULL" for the reply_block.
189 * Note that it is assumed that the reply has already been
190 * matched to the key (and signatures checked) as it would
191 * be done with the "get_key" function.
193 * @param ctx block contxt
194 * @param type block type
195 * @param query original query (hash)
196 * @param bf pointer to bloom filter associated with query; possibly updated (!)
197 * @param bf_mutator mutation value for bf
198 * @param xquery extended query data (can be NULL, depending on type)
199 * @param xquery_size number of bytes in xquery
200 * @param reply_block response to validate
201 * @param reply_block_size number of bytes in reply block
202 * @return characterization of result
204 enum GNUNET_BLOCK_EvaluationResult
205 GNUNET_BLOCK_evaluate (struct GNUNET_BLOCK_Context *ctx,
206 enum GNUNET_BLOCK_Type type,
207 const GNUNET_HashCode * query,
208 struct GNUNET_CONTAINER_BloomFilter **bf,
209 int32_t bf_mutator, const void *xquery,
210 size_t xquery_size, const void *reply_block,
211 size_t reply_block_size)
213 struct GNUNET_BLOCK_PluginFunctions *plugin = find_plugin (ctx, type);
216 return GNUNET_BLOCK_EVALUATION_TYPE_NOT_SUPPORTED;
217 return plugin->evaluate (plugin->cls, type, query, bf, bf_mutator, xquery,
218 xquery_size, reply_block, reply_block_size);
223 * Function called to obtain the key for a block.
225 * @param ctx block context
226 * @param type block type
227 * @param block block to get the key for
228 * @param block_size number of bytes in block
229 * @param key set to the key (query) for the given block
230 * @return GNUNET_OK on success, GNUNET_SYSERR if type not supported
231 * (or if extracting a key from a block of this type does not work)
234 GNUNET_BLOCK_get_key (struct GNUNET_BLOCK_Context *ctx,
235 enum GNUNET_BLOCK_Type type, const void *block,
236 size_t block_size, GNUNET_HashCode * key)
238 struct GNUNET_BLOCK_PluginFunctions *plugin = find_plugin (ctx, type);
241 return GNUNET_BLOCK_EVALUATION_TYPE_NOT_SUPPORTED;
242 return plugin->get_key (plugin->cls, type, block, block_size, key);
247 * How many bytes should a bloomfilter be if we have already seen
248 * entry_count responses? Note that GNUNET_CONSTANTS_BLOOMFILTER_K gives us the number
249 * of bits set per entry. Furthermore, we should not re-size the
250 * filter too often (to keep it cheap).
252 * Since other peers will also add entries but not resize the filter,
253 * we should generally pick a slightly larger size than what the
254 * strict math would suggest.
256 * @return must be a power of two and smaller or equal to 2^15.
259 compute_bloomfilter_size (unsigned int entry_count)
262 unsigned int ideal = (entry_count * GNUNET_CONSTANTS_BLOOMFILTER_K) / 4;
263 uint16_t max = 1 << 15;
265 if (entry_count > max)
268 while ((size < max) && (size < ideal))
277 * Construct a bloom filter that would filter out the given
280 * @param bf_mutator mutation value to use
281 * @param seen_results results already seen
282 * @param seen_results_count number of entries in 'seen_results'
283 * @return NULL if seen_results_count is 0, otherwise a BF
284 * that would match the given results.
286 struct GNUNET_CONTAINER_BloomFilter *
287 GNUNET_BLOCK_construct_bloomfilter (int32_t bf_mutator,
288 const GNUNET_HashCode * seen_results,
289 unsigned int seen_results_count)
291 struct GNUNET_CONTAINER_BloomFilter *bf;
292 GNUNET_HashCode mhash;
296 nsize = compute_bloomfilter_size (seen_results_count);
297 bf = GNUNET_CONTAINER_bloomfilter_init (NULL, nsize,
298 GNUNET_CONSTANTS_BLOOMFILTER_K);
299 for (i = 0; i < seen_results_count; i++)
301 GNUNET_BLOCK_mingle_hash (&seen_results[i], bf_mutator, &mhash);
302 GNUNET_CONTAINER_bloomfilter_add (bf, &mhash);