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22 * @file block/plugin_block_template.c
23 * @brief template for a block plugin
24 * @author Christian Grothoff
28 #include "gnunet_block_plugin.h"
29 #include "gnunet_block_group_lib.h"
31 #define DEBUG_TEMPLATE GNUNET_EXTRA_LOGGING
34 * Number of bits we set per entry in the bloomfilter.
37 #define BLOOMFILTER_K 16
41 * How big is the BF we use for DHT blocks?
43 #define TEMPLATE_BF_SIZE 8
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_template_create_group (void *cls,
91 enum GNUNET_BLOCK_Type type,
100 guard = va_arg (va, const char *);
101 if (0 == memcmp (guard,
103 strlen ("seen-set-size")))
104 bf_size = compute_bloomfilter_size (va_arg (va, unsigned int));
105 else if (0 == memcmp (guard,
107 strlen ("filter-size")))
108 bf_size = va_arg (va, unsigned int);
112 bf_size = TEMPLATE_BF_SIZE;
114 GNUNET_break (NULL == va_arg (va, const char *));
115 return GNUNET_BLOCK_GROUP_bf_create (cls,
126 * Function called to validate a reply or a request. For
127 * request evaluation, simply pass "NULL" for the reply_block.
130 * @param type block type
131 * @param group block group to use
132 * @param eo control flags
133 * @param query original query (hash)
134 * @param xquery extrended query data (can be NULL, depending on type)
135 * @param xquery_size number of bytes in xquery
136 * @param reply_block response to validate
137 * @param reply_block_size number of bytes in reply block
138 * @return characterization of result
140 static enum GNUNET_BLOCK_EvaluationResult
141 block_plugin_template_evaluate (void *cls,
142 enum GNUNET_BLOCK_Type type,
143 struct GNUNET_BLOCK_Group *group,
144 enum GNUNET_BLOCK_EvaluationOptions eo,
145 const struct GNUNET_HashCode *query,
148 const void *reply_block,
149 size_t reply_block_size)
151 struct GNUNET_HashCode chash;
153 if (NULL == reply_block)
154 return GNUNET_BLOCK_EVALUATION_REQUEST_VALID;
155 GNUNET_CRYPTO_hash (reply_block,
159 GNUNET_BLOCK_GROUP_bf_test_and_set (group,
161 return GNUNET_BLOCK_EVALUATION_OK_DUPLICATE;
162 return GNUNET_BLOCK_EVALUATION_TYPE_NOT_SUPPORTED;
167 * Function called to obtain the key for a block.
170 * @param type block type
171 * @param block block to get the key for
172 * @param block_size number of bytes in block
173 * @param key set to the key (query) for the given block
174 * @return #GNUNET_OK on success, #GNUNET_SYSERR if type not supported
175 * (or if extracting a key from a block of this type does not work)
178 block_plugin_template_get_key (void *cls,
179 enum GNUNET_BLOCK_Type type,
182 struct GNUNET_HashCode *key)
184 return GNUNET_SYSERR;
189 * Entry point for the plugin.
192 libgnunet_plugin_block_template_init (void *cls)
194 static enum GNUNET_BLOCK_Type types[] =
196 /* FIXME: insert supported block types here */
197 GNUNET_BLOCK_TYPE_ANY /* end of list */
199 struct GNUNET_BLOCK_PluginFunctions *api;
201 api = GNUNET_new (struct GNUNET_BLOCK_PluginFunctions);
202 api->evaluate = &block_plugin_template_evaluate;
203 api->get_key = &block_plugin_template_get_key;
204 api->create_group = &block_plugin_template_create_group;
211 * Exit point from the plugin.
214 libgnunet_plugin_block_template_done (void *cls)
216 struct GNUNET_TRANSPORT_PluginFunctions *api = cls;
222 /* end of plugin_block_template.c */