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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 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., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, 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 #GNUNET_BLOCK_get_key() function.
*
* @param cls closure
* @param type block type
* @param eo control flags
* @param query original query (hash)
* @param bf pointer to bloom filter associated with query; possibly updated (!)
* @param bf_mutator mutation value for @a bf
* @param xquery extrended 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
*/
static enum GNUNET_BLOCK_EvaluationResult
block_plugin_fs_evaluate (void *cls,
enum GNUNET_BLOCK_Type type,
enum GNUNET_BLOCK_EvaluationOptions eo,
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 ( (0 == (eo & GNUNET_BLOCK_EO_LOCAL_SKIP_CRYPTO)) &&
(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 @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)
*/
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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