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- /*
- 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 ("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 */
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