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/*
This file is part of TALER
Copyright (C) 2014-2020 Taler Systems SA
TALER 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.
TALER 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
TALER; see the file COPYING. If not, see
<http://www.gnu.org/licenses/>
*/
/**
* @file lib/exchange_api_withdraw.c
* @brief Implementation of /reserves/$RESERVE_PUB/withdraw requests with blinding/unblinding
* @author Christian Grothoff
*/
#include "platform.h"
#include <jansson.h>
#include <microhttpd.h> /* just for HTTP status codes */
#include <gnunet/gnunet_util_lib.h>
#include <gnunet/gnunet_json_lib.h>
#include <gnunet/gnunet_curl_lib.h>
#include "taler_exchange_service.h"
#include "taler_json_lib.h"
#include "exchange_api_handle.h"
#include "taler_signatures.h"
#include "exchange_api_curl_defaults.h"
/**
* @brief A Withdraw Handle
*/
struct TALER_EXCHANGE_WithdrawHandle
{
/**
* The connection to exchange this request handle will use
*/
struct TALER_EXCHANGE_Handle *exchange;
/**
* Handle for the actual (internal) withdraw operation.
*/
struct TALER_EXCHANGE_Withdraw2Handle *wh2;
/**
* Function to call with the result.
*/
TALER_EXCHANGE_WithdrawCallback cb;
/**
* Closure for @a cb.
*/
void *cb_cls;
/**
* Secrets of the planchet.
*/
struct TALER_PlanchetSecretsP ps;
/**
* Denomination key we are withdrawing.
*/
struct TALER_EXCHANGE_DenomPublicKey pk;
/**
* Hash of the public key of the coin we are signing.
*/
struct GNUNET_HashCode c_hash;
};
/**
* Function called when we're done processing the
* HTTP /reserves/$RESERVE_PUB/withdraw request.
*
* @param cls the `struct TALER_EXCHANGE_WithdrawHandle`
* @param hr HTTP response data
* @param blind_sig blind signature over the coin, NULL on error
*/
static void
handle_reserve_withdraw_finished (
void *cls,
const struct TALER_EXCHANGE_HttpResponse *hr,
const struct GNUNET_CRYPTO_RsaSignature *blind_sig)
{
struct TALER_EXCHANGE_WithdrawHandle *wh = cls;
wh->wh2 = NULL;
if (MHD_HTTP_OK != hr->http_status)
{
wh->cb (wh->cb_cls,
hr,
NULL);
}
else
{
struct TALER_FreshCoin fc;
if (GNUNET_OK !=
TALER_planchet_to_coin (&wh->pk.key,
blind_sig,
&wh->ps,
&wh->c_hash,
&fc))
{
struct TALER_EXCHANGE_HttpResponse hrx = {
.reply = hr->reply,
.http_status = 0,
.ec = TALER_EC_EXCHANGE_WITHDRAW_UNBLIND_FAILURE
};
wh->cb (wh->cb_cls,
&hrx,
NULL);
}
else
{
wh->cb (wh->cb_cls,
hr,
&fc.sig);
GNUNET_CRYPTO_rsa_signature_free (fc.sig.rsa_signature);
}
}
TALER_EXCHANGE_withdraw_cancel (wh);
}
/**
* Withdraw a coin from the exchange using a /reserve/withdraw request. Note
* that to ensure that no money is lost in case of hardware failures,
* the caller must have committed (most of) the arguments to disk
* before calling, and be ready to repeat the request with the same
* arguments in case of failures.
*
* @param exchange the exchange handle; the exchange must be ready to operate
* @param pk kind of coin to create
* @param reserve_priv private key of the reserve to withdraw from
* @param ps secrets of the planchet
* caller must have committed this value to disk before the call (with @a pk)
* @param res_cb the callback to call when the final result for this request is available
* @param res_cb_cls closure for the above callback
* @return handle for the operation on success, NULL on error, i.e.
* if the inputs are invalid (i.e. denomination key not with this exchange).
* In this case, the callback is not called.
*/
struct TALER_EXCHANGE_WithdrawHandle *
TALER_EXCHANGE_withdraw (
struct TALER_EXCHANGE_Handle *exchange,
const struct TALER_EXCHANGE_DenomPublicKey *pk,
const struct TALER_ReservePrivateKeyP *reserve_priv,
const struct TALER_PlanchetSecretsP *ps,
TALER_EXCHANGE_WithdrawCallback res_cb,
void *res_cb_cls)
{
struct TALER_PlanchetDetail pd;
struct TALER_EXCHANGE_WithdrawHandle *wh;
wh = GNUNET_new (struct TALER_EXCHANGE_WithdrawHandle);
wh->exchange = exchange;
wh->cb = res_cb;
wh->cb_cls = res_cb_cls;
wh->pk = *pk;
wh->ps = *ps;
if (GNUNET_OK !=
TALER_planchet_prepare (&pk->key,
ps,
&wh->c_hash,
&pd))
{
GNUNET_break (0);
GNUNET_free (wh);
return NULL;
}
wh->pk.key.rsa_public_key
= GNUNET_CRYPTO_rsa_public_key_dup (pk->key.rsa_public_key);
wh->wh2 = TALER_EXCHANGE_withdraw2 (exchange,
&pd,
reserve_priv,
&handle_reserve_withdraw_finished,
wh);
GNUNET_free (pd.coin_ev);
return wh;
}
/**
* Cancel a withdraw status request. This function cannot be used
* on a request handle if a response is already served for it.
*
* @param wh the withdraw sign request handle
*/
void
TALER_EXCHANGE_withdraw_cancel (struct TALER_EXCHANGE_WithdrawHandle *wh)
{
if (NULL != wh->wh2)
{
TALER_EXCHANGE_withdraw2_cancel (wh->wh2);
wh->wh2 = NULL;
}
GNUNET_CRYPTO_rsa_public_key_free (wh->pk.key.rsa_public_key);
GNUNET_free (wh);
}
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