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12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details.
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22 * @file fs/plugin_block_fs.c
23 * @brief blocks used for file-sharing
24 * @author Christian Grothoff
27 #include "gnunet_block_plugin.h"
28 #include "gnunet_fs_service.h"
30 #include "gnunet_signatures.h"
31 #include "gnunet_block_group_lib.h"
35 * Number of bits we set per entry in the bloomfilter.
38 #define BLOOMFILTER_K 16
42 * How many bytes should a bloomfilter be if we have already seen
43 * entry_count responses? Note that #GNUNET_CONSTANTS_BLOOMFILTER_K
44 * gives us the number of bits set per entry. Furthermore, we should
45 * not re-size the filter too often (to keep it cheap).
47 * Since other peers will also add entries but not resize the filter,
48 * we should generally pick a slightly larger size than what the
49 * strict math would suggest.
51 * @param entry_count expected number of entries in the Bloom filter
52 * @return must be a power of two and smaller or equal to 2^15.
55 compute_bloomfilter_size (unsigned int entry_count)
58 unsigned int ideal = (entry_count * BLOOMFILTER_K) / 4;
59 uint16_t max = 1 << 15;
61 if (entry_count > max)
64 while ((size < max) && (size < ideal))
73 * Create a new block group.
75 * @param ctx block context in which the block group is created
76 * @param type type of the block for which we are creating the group
77 * @param nonce random value used to seed the group creation
78 * @param raw_data optional serialized prior state of the group, NULL if unavailable/fresh
79 * @param raw_data_size number of bytes in @a raw_data, 0 if unavailable/fresh
80 * @param va variable arguments specific to @a type
81 * @return block group handle, NULL if block groups are not supported
82 * by this @a type of block (this is not an error)
84 static struct GNUNET_BLOCK_Group *
85 block_plugin_fs_create_group (void *cls,
86 enum GNUNET_BLOCK_Type type,
97 case GNUNET_BLOCK_TYPE_FS_DBLOCK:
98 GNUNET_break (NULL == va_arg (va, const char *));
100 case GNUNET_BLOCK_TYPE_FS_IBLOCK:
101 GNUNET_break (NULL == va_arg (va, const char *));
103 case GNUNET_BLOCK_TYPE_FS_UBLOCK:
104 guard = va_arg (va, const char *);
105 if (0 != memcmp (guard,
107 strlen ("seen-set-size")))
109 /* va-args invalid! bad bug, complain! */
115 size = compute_bloomfilter_size (va_arg (va, unsigned int));
118 size = raw_data_size; /* not for us to determine, use what we got! */
119 GNUNET_break (NULL == va_arg (va, const char *));
120 return GNUNET_BLOCK_GROUP_bf_create (cls,
128 GNUNET_break (NULL == va_arg (va, const char *));
136 * Function called to validate a reply or a request. For
137 * request evaluation, simply pass "NULL" for the reply_block.
138 * Note that it is assumed that the reply has already been
139 * matched to the key (and signatures checked) as it would
140 * be done with the #GNUNET_BLOCK_get_key() function.
143 * @param type block type
144 * @param bg group to use for evaluation
145 * @param eo control flags
146 * @param query original query (hash)
147 * @param xquery extrended query data (can be NULL, depending on type)
148 * @param xquery_size number of bytes in @a xquery
149 * @param reply_block response to validate
150 * @param reply_block_size number of bytes in @a reply_block
151 * @return characterization of result
153 static enum GNUNET_BLOCK_EvaluationResult
154 block_plugin_fs_evaluate (void *cls,
155 enum GNUNET_BLOCK_Type type,
156 struct GNUNET_BLOCK_Group *bg,
157 enum GNUNET_BLOCK_EvaluationOptions eo,
158 const struct GNUNET_HashCode *query,
161 const void *reply_block,
162 size_t reply_block_size)
164 const struct UBlock *ub;
165 struct GNUNET_HashCode hc;
166 struct GNUNET_HashCode chash;
170 case GNUNET_BLOCK_TYPE_FS_DBLOCK:
171 case GNUNET_BLOCK_TYPE_FS_IBLOCK:
172 if (0 != xquery_size)
175 return GNUNET_BLOCK_EVALUATION_REQUEST_INVALID;
177 if (NULL == reply_block)
178 return GNUNET_BLOCK_EVALUATION_REQUEST_VALID;
179 return GNUNET_BLOCK_EVALUATION_OK_LAST;
180 case GNUNET_BLOCK_TYPE_FS_UBLOCK:
181 if (0 != xquery_size)
184 return GNUNET_BLOCK_EVALUATION_REQUEST_INVALID;
186 if (NULL == reply_block)
187 return GNUNET_BLOCK_EVALUATION_REQUEST_VALID;
189 if (reply_block_size < sizeof (struct UBlock))
192 return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
195 GNUNET_CRYPTO_hash (&ub->verification_key,
196 sizeof (ub->verification_key),
198 if (0 != memcmp (&hc,
200 sizeof (struct GNUNET_HashCode)))
203 return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
205 if (reply_block_size != ntohl (ub->purpose.size) + sizeof (struct GNUNET_CRYPTO_EcdsaSignature))
208 return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
210 if ( (0 == (eo & GNUNET_BLOCK_EO_LOCAL_SKIP_CRYPTO)) &&
212 GNUNET_CRYPTO_ecdsa_verify (GNUNET_SIGNATURE_PURPOSE_FS_UBLOCK,
215 &ub->verification_key)) )
218 return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
220 GNUNET_CRYPTO_hash (reply_block,
224 GNUNET_BLOCK_GROUP_bf_test_and_set (bg,
226 return GNUNET_BLOCK_EVALUATION_OK_DUPLICATE;
227 return GNUNET_BLOCK_EVALUATION_OK_MORE;
229 return GNUNET_BLOCK_EVALUATION_TYPE_NOT_SUPPORTED;
235 * Function called to obtain the key for a block.
238 * @param type block type
239 * @param block block to get the key for
240 * @param block_size number of bytes in @a block
241 * @param key set to the key (query) for the given block
242 * @return #GNUNET_OK on success, #GNUNET_SYSERR if type not supported
243 * (or if extracting a key from a block of this type does not work)
246 block_plugin_fs_get_key (void *cls,
247 enum GNUNET_BLOCK_Type type,
250 struct GNUNET_HashCode *key)
252 const struct UBlock *ub;
256 case GNUNET_BLOCK_TYPE_FS_DBLOCK:
257 case GNUNET_BLOCK_TYPE_FS_IBLOCK:
258 GNUNET_CRYPTO_hash (block, block_size, key);
260 case GNUNET_BLOCK_TYPE_FS_UBLOCK:
261 if (block_size < sizeof (struct UBlock))
264 return GNUNET_SYSERR;
267 GNUNET_CRYPTO_hash (&ub->verification_key,
268 sizeof (ub->verification_key),
273 return GNUNET_SYSERR;
279 * Entry point for the plugin.
282 libgnunet_plugin_block_fs_init (void *cls)
284 static enum GNUNET_BLOCK_Type types[] =
286 GNUNET_BLOCK_TYPE_FS_DBLOCK,
287 GNUNET_BLOCK_TYPE_FS_IBLOCK,
288 GNUNET_BLOCK_TYPE_FS_UBLOCK,
289 GNUNET_BLOCK_TYPE_ANY /* end of list */
291 struct GNUNET_BLOCK_PluginFunctions *api;
293 api = GNUNET_new (struct GNUNET_BLOCK_PluginFunctions);
294 api->evaluate = &block_plugin_fs_evaluate;
295 api->get_key = &block_plugin_fs_get_key;
296 api->create_group = &block_plugin_fs_create_group;
303 * Exit point from the plugin.
306 libgnunet_plugin_block_fs_done (void *cls)
308 struct GNUNET_TRANSPORT_PluginFunctions *api = cls;
314 /* end of plugin_block_fs.c */