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22 * @file gns/plugin_block_gns.c
23 * @brief blocks used for GNS records
24 * @author Martin Schanzenbach
25 * @author Christian Grothoff
29 #include "gnunet_block_group_lib.h"
30 #include "gnunet_block_plugin.h"
31 #include "gnunet_namestore_service.h"
32 #include "gnunet_signatures.h"
35 * Number of bits we set per entry in the bloomfilter.
36 * Do not change! -from fs
38 #define BLOOMFILTER_K 16
41 * How big is the BF we use for GNS blocks?
47 * How many bytes should a bloomfilter be if we have already seen
48 * entry_count responses? Note that #GNUNET_CONSTANTS_BLOOMFILTER_K
49 * gives us the number of bits set per entry. Furthermore, we should
50 * not re-size the filter too often (to keep it cheap).
52 * Since other peers will also add entries but not resize the filter,
53 * we should generally pick a slightly larger size than what the
54 * strict math would suggest.
56 * @param entry_count expected number of entries in the Bloom filter
57 * @return must be a power of two and smaller or equal to 2^15.
60 compute_bloomfilter_size (unsigned int entry_count)
63 unsigned int ideal = (entry_count * BLOOMFILTER_K) / 4;
64 uint16_t max = 1 << 15;
66 if (entry_count > max)
69 while ((size < max) && (size < ideal))
78 * Create a new block group.
80 * @param ctx block context in which the block group is created
81 * @param type type of the block for which we are creating the group
82 * @param nonce random value used to seed the group creation
83 * @param raw_data optional serialized prior state of the group, NULL if unavailable/fresh
84 * @param raw_data_size number of bytes in @a raw_data, 0 if unavailable/fresh
85 * @param va variable arguments specific to @a type
86 * @return block group handle, NULL if block groups are not supported
87 * by this @a type of block (this is not an error)
89 static struct GNUNET_BLOCK_Group *
90 block_plugin_gns_create_group (void *cls,
91 enum GNUNET_BLOCK_Type type,
100 guard = va_arg (va, const char *);
101 if (0 == strcmp (guard,
103 bf_size = compute_bloomfilter_size (va_arg (va, unsigned int));
104 else if (0 == strcmp (guard,
106 bf_size = va_arg (va, unsigned int);
110 bf_size = GNS_BF_SIZE;
112 GNUNET_break (NULL == va_arg (va, const char *));
113 return GNUNET_BLOCK_GROUP_bf_create (cls,
124 * Function called to validate a reply or a request. For
125 * request evaluation, simply pass "NULL" for the reply_block.
126 * Note that it is assumed that the reply has already been
127 * matched to the key (and signatures checked) as it would
128 * be done with the "get_key" function.
131 * @param type block type
132 * @param bg block group to use for evaluation
133 * @param eo control flags
134 * @param query original query (hash)
135 * @param xquery extrended query data (can be NULL, depending on @a type)
136 * @param xquery_size number of bytes in @a xquery
137 * @param reply_block response to validate
138 * @param reply_block_size number of bytes in @a reply_block
139 * @return characterization of result
141 static enum GNUNET_BLOCK_EvaluationResult
142 block_plugin_gns_evaluate (void *cls,
143 enum GNUNET_BLOCK_Type type,
144 struct GNUNET_BLOCK_Group *bg,
145 enum GNUNET_BLOCK_EvaluationOptions eo,
146 const struct GNUNET_HashCode *query,
149 const void *reply_block,
150 size_t reply_block_size)
152 const struct GNUNET_GNSRECORD_Block *block;
153 struct GNUNET_HashCode h;
154 struct GNUNET_HashCode chash;
156 if (type != GNUNET_BLOCK_TYPE_GNS_NAMERECORD)
157 return GNUNET_BLOCK_EVALUATION_TYPE_NOT_SUPPORTED;
158 if (NULL == reply_block)
160 if (0 != xquery_size)
163 return GNUNET_BLOCK_EVALUATION_REQUEST_INVALID;
165 return GNUNET_BLOCK_EVALUATION_REQUEST_VALID;
168 /* this is a reply */
169 if (reply_block_size < sizeof (struct GNUNET_GNSRECORD_Block))
172 return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
175 if (ntohl (block->purpose.size) + sizeof (struct GNUNET_CRYPTO_EcdsaSignature) + sizeof (struct GNUNET_CRYPTO_EcdsaPublicKey) !=
179 return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
181 GNUNET_CRYPTO_hash (&block->derived_key,
182 sizeof (block->derived_key),
184 if (0 != memcmp (&h, query, sizeof (struct GNUNET_HashCode)))
187 return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
190 GNUNET_GNSRECORD_block_verify (block))
193 return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
195 GNUNET_CRYPTO_hash (reply_block,
199 GNUNET_BLOCK_GROUP_bf_test_and_set (bg,
201 return GNUNET_BLOCK_EVALUATION_OK_DUPLICATE;
202 return GNUNET_BLOCK_EVALUATION_OK_MORE;
207 * Function called to obtain the key for a block.
210 * @param type block type
211 * @param reply_block block to get the key for
212 * @param reply_block_size number of bytes in @a reply_block
213 * @param key set to the key (query) for the given block
214 * @return #GNUNET_OK on success, #GNUNET_SYSERR if type not supported
215 * (or if extracting a key from a block of this type does not work)
218 block_plugin_gns_get_key (void *cls,
219 enum GNUNET_BLOCK_Type type,
220 const void *reply_block,
221 size_t reply_block_size,
222 struct GNUNET_HashCode *key)
224 const struct GNUNET_GNSRECORD_Block *block;
226 if (type != GNUNET_BLOCK_TYPE_GNS_NAMERECORD)
227 return GNUNET_SYSERR;
228 if (reply_block_size < sizeof (struct GNUNET_GNSRECORD_Block))
231 return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
234 GNUNET_CRYPTO_hash (&block->derived_key,
235 sizeof (block->derived_key),
242 * Entry point for the plugin.
245 libgnunet_plugin_block_gns_init (void *cls)
247 static enum GNUNET_BLOCK_Type types[] =
249 GNUNET_BLOCK_TYPE_GNS_NAMERECORD,
250 GNUNET_BLOCK_TYPE_ANY /* end of list */
252 struct GNUNET_BLOCK_PluginFunctions *api;
254 api = GNUNET_new (struct GNUNET_BLOCK_PluginFunctions);
255 api->evaluate = &block_plugin_gns_evaluate;
256 api->get_key = &block_plugin_gns_get_key;
257 api->create_group = &block_plugin_gns_create_group;
264 * Exit point from the plugin.
267 libgnunet_plugin_block_gns_done (void *cls)
269 struct GNUNET_TRANSPORT_PluginFunctions *api = cls;
275 /* end of plugin_block_gns.c */