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/*
This file is part of GNUnet.
Copyright (C) 2014 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/>.
*/
#include "secretsharing.h"
/**
* Read a share from its binary representation.
*
* @param data Binary representation of the share.
* @param len Length of @a data.
* @param[out] readlen Number of bytes read,
* ignored if NULL.
* @return The share, or NULL on error.
*/
struct GNUNET_SECRETSHARING_Share *
GNUNET_SECRETSHARING_share_read (const void *data,
size_t len,
size_t *readlen)
{
struct GNUNET_SECRETSHARING_Share *share;
const struct GNUNET_SECRETSHARING_ShareHeaderNBO *sh = data;
const char *p;
size_t n;
uint16_t payload_size;
payload_size = ntohs (sh->num_peers) *
(sizeof (uint16_t) + sizeof (struct GNUNET_SECRETSHARING_FieldElement) +
sizeof (struct GNUNET_PeerIdentity));
if (NULL != readlen)
*readlen = payload_size + sizeof *sh;
share = GNUNET_new (struct GNUNET_SECRETSHARING_Share);
share->threshold = ntohs (sh->threshold);
share->num_peers = ntohs (sh->num_peers);
share->my_peer = ntohs (sh->my_peer);
share->my_share = sh->my_share;
share->public_key = sh->public_key;
p = (const char *) &sh[1];
n = share->num_peers * sizeof (struct GNUNET_PeerIdentity);
share->peers = GNUNET_new_array (share->num_peers,
struct GNUNET_PeerIdentity);
GNUNET_memcpy (share->peers, p, n);
p += n;
n = share->num_peers * sizeof (struct GNUNET_SECRETSHARING_FieldElement);
share->sigmas = GNUNET_new_array (share->num_peers,
struct GNUNET_SECRETSHARING_FieldElement);
GNUNET_memcpy (share->sigmas, p, n);
p += n;
n = share->num_peers * sizeof (uint16_t);
share->original_indices = GNUNET_new_array (share->num_peers,
uint16_t);
GNUNET_memcpy (share->original_indices, p, n);
return share;
}
/**
* Convert a share to its binary representation.
* Can be called with a NULL @a buf to get the size of the share.
*
* @param share Share to write.
* @param buf Buffer to write to.
* @param buflen Number of writable bytes in @a buf.
* @param[out] writelen Pointer to store number of bytes written,
* ignored if NULL.
* @return #GNUNET_OK on success, #GNUNET_SYSERR on failure.
*/
int
GNUNET_SECRETSHARING_share_write (const struct GNUNET_SECRETSHARING_Share *share,
void *buf, size_t buflen, size_t *writelen)
{
uint16_t payload_size;
struct GNUNET_SECRETSHARING_ShareHeaderNBO *sh;
char *p;
int n;
payload_size = share->num_peers *
(sizeof (uint16_t) + sizeof (struct GNUNET_SECRETSHARING_FieldElement) +
sizeof (struct GNUNET_PeerIdentity));
if (NULL != writelen)
*writelen = payload_size + sizeof (struct GNUNET_SECRETSHARING_ShareHeaderNBO);
/* just a query for the writelen */
if (buf == NULL)
return GNUNET_OK;
/* wrong buffer size */
if (buflen < payload_size + sizeof (struct GNUNET_SECRETSHARING_ShareHeaderNBO))
return GNUNET_SYSERR;
sh = buf;
sh->threshold = htons (share->threshold);
sh->num_peers = htons (share->num_peers);
sh->my_peer = htons (share->my_peer);
sh->my_share = share->my_share;
sh->public_key = share->public_key;
p = (void *) &sh[1];
n = share->num_peers * sizeof (struct GNUNET_PeerIdentity);
GNUNET_memcpy (p, share->peers, n);
p += n;
n = share->num_peers * sizeof (struct GNUNET_SECRETSHARING_FieldElement);
GNUNET_memcpy (p, share->sigmas, n);
p += n;
n = share->num_peers * sizeof (uint16_t);
GNUNET_memcpy (p, share->original_indices, n);
return GNUNET_OK;
}
void
GNUNET_SECRETSHARING_share_destroy (struct GNUNET_SECRETSHARING_Share *share)
{
GNUNET_free (share->original_indices);
share->original_indices = NULL;
GNUNET_free (share->sigmas);
share->sigmas = NULL;
GNUNET_free (share->peers);
share->peers = NULL;
GNUNET_free (share);
}
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