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- /*
- This file is part of GNUnet
- (C) 2010, 2013 Christian Grothoff (and other contributing authors)
- GNUnet is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published
- by the Free Software Foundation; either version 3, 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
- General Public License for more details.
- You should have received a copy of the GNU General Public License
- along with GNUnet; see the file COPYING. If not, write to the
- Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- Boston, MA 02111-1307, USA.
- */
- /**
- * @file fs/plugin_block_fs.c
- * @brief blocks used for file-sharing
- * @author Christian Grothoff
- */
- #include "platform.h"
- #include "gnunet_block_plugin.h"
- #include "gnunet_fs_service.h"
- #include "block_fs.h"
- #include "gnunet_signatures.h"
- /**
- * Number of bits we set per entry in the bloomfilter.
- * Do not change!
- */
- #define BLOOMFILTER_K 16
- /**
- * 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 type block type
- * @param query original query (hash)
- * @param bf pointer to bloom filter associated with query; possibly updated (!)
- * @param bf_mutator mutation value for bf
- * @param xquery extrended query data (can be NULL, depending on type)
- * @param xquery_size number of bytes in xquery
- * @param reply_block response to validate
- * @param reply_block_size number of bytes in reply block
- * @return characterization of result
- */
- static enum GNUNET_BLOCK_EvaluationResult
- block_plugin_fs_evaluate (void *cls, enum GNUNET_BLOCK_Type type,
- const struct GNUNET_HashCode *query,
- struct GNUNET_CONTAINER_BloomFilter **bf,
- int32_t bf_mutator, const void *xquery,
- size_t xquery_size, const void *reply_block,
- size_t reply_block_size)
- {
- const struct UBlock *ub;
- struct GNUNET_HashCode hc;
- struct GNUNET_HashCode chash;
- struct GNUNET_HashCode mhash;
- switch (type)
- {
- case GNUNET_BLOCK_TYPE_FS_DBLOCK:
- case GNUNET_BLOCK_TYPE_FS_IBLOCK:
- if (0 != xquery_size)
- {
- GNUNET_break_op (0);
- return GNUNET_BLOCK_EVALUATION_REQUEST_INVALID;
- }
- if (NULL == reply_block)
- return GNUNET_BLOCK_EVALUATION_REQUEST_VALID;
- return GNUNET_BLOCK_EVALUATION_OK_LAST;
- case GNUNET_BLOCK_TYPE_FS_UBLOCK:
- if (0 != xquery_size)
- {
- GNUNET_break_op (0);
- return GNUNET_BLOCK_EVALUATION_REQUEST_INVALID;
- }
- if (NULL == reply_block)
- return GNUNET_BLOCK_EVALUATION_REQUEST_VALID;
- if (reply_block_size < sizeof (struct UBlock))
- {
- GNUNET_break_op (0);
- return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
- }
- ub = reply_block;
- GNUNET_CRYPTO_hash (&ub->verification_key,
- sizeof (ub->verification_key),
- &hc);
- if (0 != memcmp (&hc,
- query,
- sizeof (struct GNUNET_HashCode)))
- {
- GNUNET_break_op (0);
- return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
- }
- if (reply_block_size != ntohl (ub->purpose.size) + sizeof (struct GNUNET_CRYPTO_EcdsaSignature))
- {
- GNUNET_break_op (0);
- return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
- }
- if (GNUNET_OK !=
- GNUNET_CRYPTO_ecdsa_verify (GNUNET_SIGNATURE_PURPOSE_FS_UBLOCK,
- &ub->purpose,
- &ub->signature,
- &ub->verification_key))
- {
- GNUNET_break_op (0);
- return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
- }
- if (NULL != bf)
- {
- GNUNET_CRYPTO_hash (reply_block, reply_block_size, &chash);
- GNUNET_BLOCK_mingle_hash (&chash, bf_mutator, &mhash);
- if (NULL != *bf)
- {
- if (GNUNET_YES == GNUNET_CONTAINER_bloomfilter_test (*bf, &mhash))
- return GNUNET_BLOCK_EVALUATION_OK_DUPLICATE;
- }
- else
- {
- *bf = GNUNET_CONTAINER_bloomfilter_init (NULL, 8, BLOOMFILTER_K);
- }
- GNUNET_CONTAINER_bloomfilter_add (*bf, &mhash);
- }
- return GNUNET_BLOCK_EVALUATION_OK_MORE;
- default:
- return GNUNET_BLOCK_EVALUATION_TYPE_NOT_SUPPORTED;
- }
- }
- /**
- * Function called to obtain the key for a block.
- *
- * @param cls closure
- * @param type block type
- * @param block block to get the key for
- * @param block_size number of bytes in 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_fs_get_key (void *cls, enum GNUNET_BLOCK_Type type,
- const void *block, size_t block_size,
- struct GNUNET_HashCode *key)
- {
- const struct UBlock *ub;
- switch (type)
- {
- case GNUNET_BLOCK_TYPE_FS_DBLOCK:
- case GNUNET_BLOCK_TYPE_FS_IBLOCK:
- GNUNET_CRYPTO_hash (block, block_size, key);
- return GNUNET_OK;
- case GNUNET_BLOCK_TYPE_FS_UBLOCK:
- if (block_size < sizeof (struct UBlock))
- {
- GNUNET_break (0);
- return GNUNET_SYSERR;
- }
- ub = block;
- GNUNET_CRYPTO_hash (&ub->verification_key,
- sizeof (ub->verification_key),
- key);
- return GNUNET_OK;
- default:
- GNUNET_break (0);
- return GNUNET_SYSERR;
- }
- }
- /**
- * Entry point for the plugin.
- */
- void *
- libgnunet_plugin_block_fs_init (void *cls)
- {
- static enum GNUNET_BLOCK_Type types[] =
- {
- GNUNET_BLOCK_TYPE_FS_DBLOCK,
- GNUNET_BLOCK_TYPE_FS_IBLOCK,
- GNUNET_BLOCK_TYPE_FS_UBLOCK,
- GNUNET_BLOCK_TYPE_ANY /* end of list */
- };
- struct GNUNET_BLOCK_PluginFunctions *api;
- api = GNUNET_new (struct GNUNET_BLOCK_PluginFunctions);
- api->evaluate = &block_plugin_fs_evaluate;
- api->get_key = &block_plugin_fs_get_key;
- api->types = types;
- return api;
- }
- /**
- * Exit point from the plugin.
- */
- void *
- libgnunet_plugin_block_fs_done (void *cls)
- {
- struct GNUNET_TRANSPORT_PluginFunctions *api = cls;
- GNUNET_free (api);
- return NULL;
- }
- /* end of plugin_block_fs.c */
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