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/*
This file is part of GNUnet.
(C) 2012 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 gns/gns_common.c
* @brief helper functions shared between GNS service and block plugin
* @author Martin Schanzenbach
*/
#include "platform.h"
#include "gns_common.h"
/**
* Compute the DHT key for a name in a zone.
* DHT key is H(name) xor H(pubkey).
*
* @param name name of the record
* @param zone GADS zone
* @param key where to store the DHT key for records under this name in the given zone
*/
void
GNUNET_GNS_get_key_for_record (const char *name,
const struct GNUNET_CRYPTO_ShortHashCode *zone,
struct GNUNET_HashCode *key)
{
struct GNUNET_CRYPTO_ShortHashCode name_hash;
struct GNUNET_HashCode name_hash_double;
struct GNUNET_HashCode zone_hash_double;
GNUNET_CRYPTO_short_hash (name,
strlen (name),
&name_hash);
GNUNET_CRYPTO_short_hash_double (&name_hash, &name_hash_double);
GNUNET_CRYPTO_short_hash_double (zone, &zone_hash_double);
GNUNET_CRYPTO_hash_xor(&name_hash_double, &zone_hash_double, key);
}
/**
* Compute the zone identifier from a given DHT key and record name.
*
* @param name name of the record
* @param key DHT key of the record
* @param zone set to the corresponding zone hash
*/
void
GNUNET_GNS_get_zone_from_key (const char *name,
const struct GNUNET_HashCode *key,
struct GNUNET_CRYPTO_ShortHashCode *zone)
{
struct GNUNET_CRYPTO_ShortHashCode name_hash;
struct GNUNET_HashCode name_hash_double;
struct GNUNET_HashCode zone_hash_double;
GNUNET_CRYPTO_short_hash(name, strlen(name), &name_hash);
GNUNET_CRYPTO_short_hash_double(&name_hash, &name_hash_double);
GNUNET_CRYPTO_hash_xor(key, &name_hash_double, &zone_hash_double);
GNUNET_CRYPTO_short_hash_from_truncation (&zone_hash_double, zone);
}
/* end of gns_common.c */
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