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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 secretsharing/secretsharing_api.c
* @brief
* @author Florian Dold
*/
#include "platform.h"
#include "gnunet_util_lib.h"
#include "gnunet_secretsharing_service.h"
#include "secretsharing.h"
#define LOG(kind,...) GNUNET_log_from (kind, "secretsharing-api",__VA_ARGS__)
/**
* Session that will eventually establish a shared secred between
* the involved peers and allow encryption and cooperative decryption.
*/
struct GNUNET_SECRETSHARING_Session
{
/**
* Client connected to the secretsharing service.
*/
struct GNUNET_CLIENT_Connection *client;
/**
* Message queue for 'client'.
*/
struct GNUNET_MQ_Handle *mq;
/**
* Called when the secret sharing is done.
*/
GNUNET_SECRETSHARING_SecretReadyCallback secret_ready_cb;
/**
* Closure for 'secret_ready_cb'.
*/
void *secret_ready_cls;
};
struct GNUNET_SECRETSHARING_DecryptionHandle
{
/**
* Client connected to the secretsharing service.
*/
struct GNUNET_CLIENT_Connection *client;
/**
* Message queue for 'client'.
*/
struct GNUNET_MQ_Handle *mq;
/**
* Called when the secret sharing is done.
*/
GNUNET_SECRETSHARING_DecryptCallback decrypt_cb;
/**
* Closure for 'decrypt_cb'.
*/
void *decrypt_cls;
};
static void
handle_session_client_error (void *cls, enum GNUNET_MQ_Error error)
{
struct GNUNET_SECRETSHARING_Session *s = cls;
s->secret_ready_cb (s->secret_ready_cls, NULL, NULL, 0, NULL);
}
static void
handle_decrypt_client_error (void *cls, enum GNUNET_MQ_Error error)
{
GNUNET_assert (0);
}
static void
handle_secret_ready (void *cls, const struct GNUNET_MessageHeader *msg)
{
struct GNUNET_SECRETSHARING_Session *session = cls;
struct GNUNET_SECRETSHARING_Share *share;
const struct GNUNET_SECRETSHARING_SecretReadyMessage *m = (const void *) msg;
size_t share_size;
share_size = ntohs (m->header.size) - sizeof *m;
share = GNUNET_SECRETSHARING_share_read (&m[1], share_size, NULL);
session->secret_ready_cb (session->secret_ready_cls,
share, /* FIXME */
&share->public_key,
share->num_peers,
(struct GNUNET_PeerIdentity *) &m[1]);
}
struct GNUNET_SECRETSHARING_Session *
GNUNET_SECRETSHARING_create_session (const struct GNUNET_CONFIGURATION_Handle *cfg,
unsigned int num_peers,
const struct GNUNET_PeerIdentity *peers,
const struct GNUNET_HashCode *session_id,
struct GNUNET_TIME_Absolute deadline,
unsigned int threshold,
GNUNET_SECRETSHARING_SecretReadyCallback cb,
void *cls)
{
struct GNUNET_SECRETSHARING_Session *s;
struct GNUNET_MQ_Envelope *ev;
struct GNUNET_SECRETSHARING_CreateMessage *msg;
static const struct GNUNET_MQ_MessageHandler mq_handlers[] = {
{handle_secret_ready, GNUNET_MESSAGE_TYPE_SECRETSHARING_CLIENT_SECRET_READY, 0},
GNUNET_MQ_HANDLERS_END
};
s = GNUNET_new (struct GNUNET_SECRETSHARING_Session);
s->client = GNUNET_CLIENT_connect ("secretsharing", cfg);
s->secret_ready_cb = cb;
s->secret_ready_cls = cls;
GNUNET_assert (NULL != s->client);
s->mq = GNUNET_MQ_queue_for_connection_client (s->client, mq_handlers,
handle_session_client_error, s);
GNUNET_assert (NULL != s->mq);
ev = GNUNET_MQ_msg_extra (msg,
num_peers * sizeof (struct GNUNET_PeerIdentity),
GNUNET_MESSAGE_TYPE_SECRETSHARING_CLIENT_GENERATE);
msg->threshold = htons (threshold);
msg->num_peers = htons (num_peers);
msg->session_id = *session_id;
msg->deadline = GNUNET_TIME_absolute_hton (deadline);
memcpy (&msg[1], peers, num_peers * sizeof (struct GNUNET_PeerIdentity));
GNUNET_MQ_send (s->mq, ev);
LOG (GNUNET_ERROR_TYPE_DEBUG, "secretsharing session created with %u peers\n",
num_peers);
return s;
}
static void
handle_decrypt_done (void *cls, const struct GNUNET_MessageHeader *msg)
{
GNUNET_assert (0);
}
/**
* Publish the given ciphertext for decryption. Once a sufficient (>=k) number of peers has
* published the same value, it will be decrypted.
*
* When the operation is canceled, the decrypt_cb is not called anymore, but the calling
* peer may already have irrevocably contributed his share for the decryption of the value.
*
* @param share our secret share to use for decryption
* @param ciphertext ciphertext to publish in order to decrypt it (if enough peers agree)
* @param decrypt_cb callback called once the decryption succeeded
* @param decrypt_cb_cls closure for @a decrypt_cb
* @return handle to cancel the operation
*/
struct GNUNET_SECRETSHARING_DecryptionHandle *
GNUNET_SECRETSHARING_decrypt (struct GNUNET_CONFIGURATION_Handle *cfg,
struct GNUNET_SECRETSHARING_Share *share,
struct GNUNET_SECRETSHARING_Ciphertext *ciphertext,
struct GNUNET_TIME_Absolute deadline,
GNUNET_SECRETSHARING_DecryptCallback decrypt_cb,
void *decrypt_cb_cls)
{
struct GNUNET_SECRETSHARING_DecryptionHandle *s;
struct GNUNET_MQ_Envelope *ev;
struct GNUNET_SECRETSHARING_DecryptRequestMessage *msg;
static const struct GNUNET_MQ_MessageHandler mq_handlers[] = {
{handle_decrypt_done, GNUNET_MESSAGE_TYPE_SECRETSHARING_CLIENT_DECRYPT_DONE, 0},
GNUNET_MQ_HANDLERS_END
};
size_t share_size;
s = GNUNET_new (struct GNUNET_SECRETSHARING_DecryptionHandle);
s->client = GNUNET_CLIENT_connect ("secretsharing", cfg);
s->decrypt_cb = decrypt_cb;
s->decrypt_cls = decrypt_cb_cls;
GNUNET_assert (NULL != s->client);
s->mq = GNUNET_MQ_queue_for_connection_client (s->client, mq_handlers,
handle_decrypt_client_error, s);
GNUNET_assert (NULL != s->mq);
GNUNET_assert (GNUNET_OK == GNUNET_SECRETSHARING_share_write (share, NULL, 0, &share_size));
ev = GNUNET_MQ_msg_extra (msg,
share_size,
GNUNET_MESSAGE_TYPE_SECRETSHARING_CLIENT_DECRYPT);
GNUNET_assert (GNUNET_OK == GNUNET_SECRETSHARING_share_write (share, &msg[1], share_size, NULL));
msg->deadline = GNUNET_TIME_absolute_hton (deadline);
GNUNET_MQ_send (s->mq, ev);
LOG (GNUNET_ERROR_TYPE_DEBUG, "decrypt session created\n");
return s;
}
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