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- /*
- This file is part of GNUnet
- Copyright (C) 2010-2013 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 gns/plugin_block_gns.c
- * @brief blocks used for GNS records
- * @author Martin Schanzenbach
- * @author Christian Grothoff
- */
- #include "platform.h"
- #include "gnunet_block_group_lib.h"
- #include "gnunet_block_plugin.h"
- #include "gnunet_namestore_service.h"
- #include "gnunet_signatures.h"
- /**
- * Number of bits we set per entry in the bloomfilter.
- * Do not change! -from fs
- */
- #define BLOOMFILTER_K 16
- /**
- * How big is the BF we use for GNS blocks?
- */
- #define GNS_BF_SIZE 8
- /**
- * 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
- * @param va variable arguments specific to @a type
- * @return block group handle, NULL if block groups are not supported
- * by this @a type of block (this is not an error)
- */
- static struct GNUNET_BLOCK_Group *
- block_plugin_gns_create_group (void *cls,
- enum GNUNET_BLOCK_Type type,
- uint32_t nonce,
- const void *raw_data,
- size_t raw_data_size,
- va_list va)
- {
- unsigned int bf_size;
- const char *guard;
- guard = va_arg (va, const char *);
- if (0 == strcmp (guard,
- "seen-set-size"))
- bf_size = GNUNET_BLOCK_GROUP_compute_bloomfilter_size (va_arg (va, unsigned
- int),
- BLOOMFILTER_K);
- else if (0 == strcmp (guard,
- "filter-size"))
- bf_size = va_arg (va, unsigned int);
- else
- {
- GNUNET_break (0);
- bf_size = GNS_BF_SIZE;
- }
- GNUNET_break (NULL == va_arg (va, const char *));
- return GNUNET_BLOCK_GROUP_bf_create (cls,
- bf_size,
- BLOOMFILTER_K,
- type,
- nonce,
- raw_data,
- raw_data_size);
- }
- /**
- * 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 cls closure
- * @param ctx block context
- * @param type block type
- * @param bg block group to use for evaluation
- * @param eo control flags
- * @param query original query (hash)
- * @param xquery extrended query data (can be NULL, depending on @a 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
- */
- static enum GNUNET_BLOCK_EvaluationResult
- block_plugin_gns_evaluate (void *cls,
- struct GNUNET_BLOCK_Context *ctx,
- enum GNUNET_BLOCK_Type type,
- struct GNUNET_BLOCK_Group *bg,
- 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)
- {
- const struct GNUNET_GNSRECORD_Block *block;
- struct GNUNET_HashCode h;
- struct GNUNET_HashCode chash;
- if (type != GNUNET_BLOCK_TYPE_GNS_NAMERECORD)
- return GNUNET_BLOCK_EVALUATION_TYPE_NOT_SUPPORTED;
- if (NULL == reply_block)
- {
- if (0 != xquery_size)
- {
- GNUNET_break_op (0);
- return GNUNET_BLOCK_EVALUATION_REQUEST_INVALID;
- }
- return GNUNET_BLOCK_EVALUATION_REQUEST_VALID;
- }
- /* this is a reply */
- if (reply_block_size < sizeof(struct GNUNET_GNSRECORD_Block))
- {
- GNUNET_break_op (0);
- return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
- }
- block = reply_block;
- if (ntohl (block->purpose.size) + sizeof(struct
- GNUNET_CRYPTO_EcdsaSignature)
- + sizeof(struct GNUNET_CRYPTO_EcdsaPublicKey) !=
- reply_block_size)
- {
- GNUNET_break_op (0);
- return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
- }
- GNUNET_CRYPTO_hash (&block->derived_key,
- sizeof(block->derived_key),
- &h);
- if (0 != GNUNET_memcmp (&h, query))
- {
- GNUNET_break_op (0);
- return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
- }
- if (GNUNET_OK !=
- GNUNET_GNSRECORD_block_verify (block))
- {
- GNUNET_break_op (0);
- return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
- }
- GNUNET_CRYPTO_hash (reply_block,
- reply_block_size,
- &chash);
- if (GNUNET_YES ==
- GNUNET_BLOCK_GROUP_bf_test_and_set (bg,
- &chash))
- return GNUNET_BLOCK_EVALUATION_OK_DUPLICATE;
- return GNUNET_BLOCK_EVALUATION_OK_MORE;
- }
- /**
- * Function called to obtain the key for a block.
- *
- * @param cls closure
- * @param type block type
- * @param reply_block block to get the key for
- * @param reply_block_size number of bytes in @a reply_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)
- */
- static int
- block_plugin_gns_get_key (void *cls,
- enum GNUNET_BLOCK_Type type,
- const void *reply_block,
- size_t reply_block_size,
- struct GNUNET_HashCode *key)
- {
- const struct GNUNET_GNSRECORD_Block *block;
- if (type != GNUNET_BLOCK_TYPE_GNS_NAMERECORD)
- return GNUNET_SYSERR;
- if (reply_block_size < sizeof(struct GNUNET_GNSRECORD_Block))
- {
- GNUNET_break_op (0);
- return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
- }
- block = reply_block;
- GNUNET_CRYPTO_hash (&block->derived_key,
- sizeof(block->derived_key),
- key);
- return GNUNET_OK;
- }
- /**
- * Entry point for the plugin.
- */
- void *
- libgnunet_plugin_block_gns_init (void *cls)
- {
- static enum GNUNET_BLOCK_Type types[] = {
- GNUNET_BLOCK_TYPE_GNS_NAMERECORD,
- GNUNET_BLOCK_TYPE_ANY /* end of list */
- };
- struct GNUNET_BLOCK_PluginFunctions *api;
- api = GNUNET_new (struct GNUNET_BLOCK_PluginFunctions);
- api->evaluate = &block_plugin_gns_evaluate;
- api->get_key = &block_plugin_gns_get_key;
- api->create_group = &block_plugin_gns_create_group;
- api->types = types;
- return api;
- }
- /**
- * Exit point from the plugin.
- */
- void *
- libgnunet_plugin_block_gns_done (void *cls)
- {
- struct GNUNET_BLOCK_PluginFunctions *api = cls;
- GNUNET_free (api);
- return NULL;
- }
- /* end of plugin_block_gns.c */
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