544 lines
20 KiB
C
544 lines
20 KiB
C
/*
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This file is part of TALER
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Copyright (C) 2014, 2015 GNUnet e.V.
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TALER is free software; you can redistribute it and/or modify it under the
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terms of the GNU General Public License as published by the Free Software
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Foundation; either version 3, or (at your option) any later version.
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TALER is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
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A PARTICULAR PURPOSE. See the GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along with
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TALER; see the file COPYING. If not, If not, see
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<http://www.gnu.org/licenses/>
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*/
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/**
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* @file exchange-lib/exchange_api_deposit.c
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* @brief Implementation of the /deposit request of the exchange's HTTP API
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* @author Sree Harsha Totakura <sreeharsha@totakura.in>
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* @author Christian Grothoff
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*/
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#include "platform.h"
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#include <curl/curl.h>
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#include <jansson.h>
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#include <microhttpd.h> /* just for HTTP status codes */
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#include <gnunet/gnunet_util_lib.h>
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#include <gnunet/gnunet_json_lib.h>
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#include <gnunet/gnunet_curl_lib.h>
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#include "taler_json_lib.h"
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#include "taler_exchange_service.h"
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#include "exchange_api_common.h"
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#include "exchange_api_handle.h"
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#include "taler_signatures.h"
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/**
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* @brief A Deposit Handle
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*/
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struct TALER_EXCHANGE_DepositHandle
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{
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/**
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* The connection to exchange this request handle will use
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*/
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struct TALER_EXCHANGE_Handle *exchange;
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/**
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* The url for this request.
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*/
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char *url;
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/**
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* JSON encoding of the request to POST.
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*/
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char *json_enc;
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/**
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* Handle for the request.
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*/
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struct GNUNET_CURL_Job *job;
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/**
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* Function to call with the result.
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*/
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TALER_EXCHANGE_DepositResultCallback cb;
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/**
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* Closure for @a cb.
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*/
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void *cb_cls;
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/**
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* Information the exchange should sign in response.
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*/
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struct TALER_DepositConfirmationPS depconf;
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/**
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* Value of the /deposit transaction, including fee.
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*/
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struct TALER_Amount amount_with_fee;
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/**
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* Total value of the coin being transacted with.
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*/
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struct TALER_Amount coin_value;
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};
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/**
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* Verify that the signature on the "200 OK" response
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* from the exchange is valid.
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*
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* @param dh deposit handle
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* @param json json reply with the signature
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* @param exchange_pub set to the exchange's public key
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* @return #GNUNET_OK if the signature is valid, #GNUNET_SYSERR if not
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*/
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static int
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verify_deposit_signature_ok (const struct TALER_EXCHANGE_DepositHandle *dh,
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const json_t *json,
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struct TALER_ExchangePublicKeyP *exchange_pub)
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{
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struct TALER_ExchangeSignatureP exchange_sig;
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const struct TALER_EXCHANGE_Keys *key_state;
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struct GNUNET_JSON_Specification spec[] = {
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GNUNET_JSON_spec_fixed_auto ("sig", &exchange_sig),
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GNUNET_JSON_spec_fixed_auto ("pub", exchange_pub),
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GNUNET_JSON_spec_end()
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};
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if (GNUNET_OK !=
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GNUNET_JSON_parse (json,
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spec,
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NULL, NULL))
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{
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GNUNET_break_op (0);
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return GNUNET_SYSERR;
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}
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key_state = TALER_EXCHANGE_get_keys (dh->exchange);
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if (GNUNET_OK !=
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TALER_EXCHANGE_test_signing_key (key_state,
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exchange_pub))
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{
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GNUNET_break_op (0);
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return GNUNET_SYSERR;
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}
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if (GNUNET_OK !=
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GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_EXCHANGE_CONFIRM_DEPOSIT,
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&dh->depconf.purpose,
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&exchange_sig.eddsa_signature,
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&exchange_pub->eddsa_pub))
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{
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GNUNET_break_op (0);
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return GNUNET_SYSERR;
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}
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return GNUNET_OK;
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}
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/**
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* Verify that the signatures on the "403 FORBIDDEN" response from the
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* exchange demonstrating customer double-spending are valid.
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*
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* @param dh deposit handle
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* @param json json reply with the signature(s) and transaction history
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* @return #GNUNET_OK if the signature(s) is valid, #GNUNET_SYSERR if not
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*/
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static int
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verify_deposit_signature_forbidden (const struct TALER_EXCHANGE_DepositHandle *dh,
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const json_t *json)
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{
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json_t *history;
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struct TALER_Amount total;
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history = json_object_get (json,
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"history");
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if (GNUNET_OK !=
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TALER_EXCHANGE_verify_coin_history (dh->coin_value.currency,
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&dh->depconf.coin_pub,
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history,
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&total))
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{
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GNUNET_break_op (0);
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return GNUNET_SYSERR;
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}
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if (GNUNET_OK !=
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TALER_amount_add (&total,
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&total,
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&dh->amount_with_fee))
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{
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/* clearly not OK if our transaction would have caused
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the overflow... */
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return GNUNET_OK;
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}
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if (0 >= TALER_amount_cmp (&total,
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&dh->coin_value))
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{
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/* transaction should have still fit */
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GNUNET_break (0);
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return GNUNET_SYSERR;
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}
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/* everything OK, proof of double-spending was provided */
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return GNUNET_OK;
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}
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/**
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* Function called when we're done processing the
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* HTTP /deposit request.
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*
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* @param cls the `struct TALER_EXCHANGE_DepositHandle`
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* @param response_code HTTP response code, 0 on error
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* @param json parsed JSON result, NULL on error
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*/
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static void
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handle_deposit_finished (void *cls,
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long response_code,
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const json_t *json)
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{
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struct TALER_EXCHANGE_DepositHandle *dh = cls;
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struct TALER_ExchangePublicKeyP exchange_pub;
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struct TALER_ExchangePublicKeyP *ep = NULL;
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dh->job = NULL;
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switch (response_code)
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{
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case 0:
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break;
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case MHD_HTTP_OK:
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if (GNUNET_OK !=
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verify_deposit_signature_ok (dh,
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json,
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&exchange_pub))
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{
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GNUNET_break_op (0);
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response_code = 0;
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}
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else
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{
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ep = &exchange_pub;
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}
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break;
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case MHD_HTTP_BAD_REQUEST:
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/* This should never happen, either us or the exchange is buggy
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(or API version conflict); just pass JSON reply to the application */
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break;
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case MHD_HTTP_FORBIDDEN:
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/* Double spending; check signatures on transaction history */
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if (GNUNET_OK !=
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verify_deposit_signature_forbidden (dh,
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json))
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{
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GNUNET_break_op (0);
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response_code = 0;
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}
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break;
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case MHD_HTTP_UNAUTHORIZED:
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/* Nothing really to verify, exchange says one of the signatures is
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invalid; as we checked them, this should never happen, we
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should pass the JSON reply to the application */
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break;
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case MHD_HTTP_NOT_FOUND:
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/* Nothing really to verify, this should never
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happen, we should pass the JSON reply to the application */
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break;
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case MHD_HTTP_INTERNAL_SERVER_ERROR:
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/* Server had an internal issue; we should retry, but this API
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leaves this to the application */
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break;
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default:
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/* unexpected response code */
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GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
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"Unexpected response code %u\n",
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(unsigned int) response_code);
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GNUNET_break (0);
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response_code = 0;
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break;
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}
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dh->cb (dh->cb_cls,
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response_code,
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ep,
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json);
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TALER_EXCHANGE_deposit_cancel (dh);
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}
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/**
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* Verify signature information about the deposit.
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*
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* @param dki public key information
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* @param amount the amount to be deposited
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* @param h_wire hash of the merchant’s account details
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* @param h_contract hash of the contact of the merchant with the customer (further details are never disclosed to the exchange)
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* @param coin_pub coin’s public key
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* @param denom_pub denomination key with which the coin is signed
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* @param denom_sig exchange’s unblinded signature of the coin
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* @param timestamp timestamp when the contract was finalized, must match approximately the current time of the exchange
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* @param transaction_id transaction id for the transaction between merchant and customer
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* @param merchant_pub the public key of the merchant (used to identify the merchant for refund requests)
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* @param refund_deadline date until which the merchant can issue a refund to the customer via the exchange (can be zero if refunds are not allowed)
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* @param coin_sig the signature made with purpose #TALER_SIGNATURE_WALLET_COIN_DEPOSIT made by the customer with the coin’s private key.
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* @return #GNUNET_OK if signatures are OK, #GNUNET_SYSERR if not
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*/
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static int
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verify_signatures (const struct TALER_EXCHANGE_DenomPublicKey *dki,
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const struct TALER_Amount *amount,
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const struct GNUNET_HashCode *h_wire,
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const struct GNUNET_HashCode *h_contract,
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const struct TALER_CoinSpendPublicKeyP *coin_pub,
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const struct TALER_DenominationSignature *denom_sig,
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const struct TALER_DenominationPublicKey *denom_pub,
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struct GNUNET_TIME_Absolute timestamp,
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uint64_t transaction_id,
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const struct TALER_MerchantPublicKeyP *merchant_pub,
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struct GNUNET_TIME_Absolute refund_deadline,
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const struct TALER_CoinSpendSignatureP *coin_sig)
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{
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struct TALER_DepositRequestPS dr;
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struct TALER_CoinPublicInfo coin_info;
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dr.purpose.purpose = htonl (TALER_SIGNATURE_WALLET_COIN_DEPOSIT);
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dr.purpose.size = htonl (sizeof (struct TALER_DepositRequestPS));
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dr.h_contract = *h_contract;
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dr.h_wire = *h_wire;
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dr.timestamp = GNUNET_TIME_absolute_hton (timestamp);
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dr.refund_deadline = GNUNET_TIME_absolute_hton (refund_deadline);
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dr.transaction_id = GNUNET_htonll (transaction_id);
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TALER_amount_hton (&dr.amount_with_fee,
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amount);
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TALER_amount_hton (&dr.deposit_fee,
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&dki->fee_deposit);
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dr.merchant = *merchant_pub;
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dr.coin_pub = *coin_pub;
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if (GNUNET_OK !=
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GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_WALLET_COIN_DEPOSIT,
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&dr.purpose,
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&coin_sig->eddsa_signature,
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&coin_pub->eddsa_pub))
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{
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TALER_LOG_WARNING ("Invalid coin signature on /deposit request\n");
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{
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char *s;
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s = TALER_amount_to_string (amount);
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TALER_LOG_DEBUG ("... amount_with_fee was %s\n", s);
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GNUNET_free (s);
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s = TALER_amount_to_string (&dki->fee_deposit);
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TALER_LOG_DEBUG ("... deposit_fee was %s\n", s);
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GNUNET_free (s);
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}
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return GNUNET_SYSERR;
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}
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/* check coin signature */
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coin_info.coin_pub = *coin_pub;
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coin_info.denom_pub = *denom_pub;
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coin_info.denom_sig = *denom_sig;
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if (GNUNET_YES !=
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TALER_test_coin_valid (&coin_info))
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{
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TALER_LOG_WARNING ("Invalid coin passed for /deposit\n");
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return GNUNET_SYSERR;
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}
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if (0 < TALER_amount_cmp (&dki->fee_deposit,
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amount))
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{
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TALER_LOG_WARNING ("Deposit amount smaller than fee\n");
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return GNUNET_SYSERR;
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}
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return GNUNET_OK;
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}
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/**
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* Submit a deposit permission to the exchange and get the exchange's response.
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* Note that while we return the response verbatim to the caller for
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* further processing, we do already verify that the response is
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* well-formed (i.e. that signatures included in the response are all
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* valid). If the exchange's reply is not well-formed, we return an
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* HTTP status code of zero to @a cb.
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*
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* We also verify that the @a coin_sig is valid for this deposit
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* request, and that the @a ub_sig is a valid signature for @a
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* coin_pub. Also, the @a exchange must be ready to operate (i.e. have
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* finished processing the /keys reply). If either check fails, we do
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* NOT initiate the transaction with the exchange and instead return NULL.
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*
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* @param exchange the exchange handle; the exchange must be ready to operate
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* @param amount the amount to be deposited
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* @param wire_deadline date until which the merchant would like the exchange to settle the balance (advisory, the exchange cannot be
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* forced to settle in the past or upon very short notice, but of course a well-behaved exchange will limit aggregation based on the advice received)
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* @param wire_details the merchant’s account details, in a format supported by the exchange
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* @param h_contract hash of the contact of the merchant with the customer (further details are never disclosed to the exchange)
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* @param coin_pub coin’s public key
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* @param denom_pub denomination key with which the coin is signed
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* @param denom_sig exchange’s unblinded signature of the coin
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* @param timestamp timestamp when the contract was finalized, must match approximately the current time of the exchange
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* @param transaction_id transaction id for the transaction between merchant and customer
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* @param merchant_pub the public key of the merchant (used to identify the merchant for refund requests)
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* @param refund_deadline date until which the merchant can issue a refund to the customer via the exchange (can be zero if refunds are not allowed); must not be after the @a wire_deadline
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* @param coin_sig the signature made with purpose #TALER_SIGNATURE_WALLET_COIN_DEPOSIT made by the customer with the coin’s private key.
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* @param cb the callback to call when a reply for this request is available
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* @param cb_cls closure for the above callback
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* @return a handle for this request; NULL if the inputs are invalid (i.e.
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* signatures fail to verify). In this case, the callback is not called.
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*/
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struct TALER_EXCHANGE_DepositHandle *
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TALER_EXCHANGE_deposit (struct TALER_EXCHANGE_Handle *exchange,
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const struct TALER_Amount *amount,
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struct GNUNET_TIME_Absolute wire_deadline,
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json_t *wire_details,
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const struct GNUNET_HashCode *h_contract,
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const struct TALER_CoinSpendPublicKeyP *coin_pub,
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const struct TALER_DenominationSignature *denom_sig,
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const struct TALER_DenominationPublicKey *denom_pub,
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struct GNUNET_TIME_Absolute timestamp,
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uint64_t transaction_id,
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const struct TALER_MerchantPublicKeyP *merchant_pub,
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struct GNUNET_TIME_Absolute refund_deadline,
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const struct TALER_CoinSpendSignatureP *coin_sig,
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TALER_EXCHANGE_DepositResultCallback cb,
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void *cb_cls)
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{
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const struct TALER_EXCHANGE_Keys *key_state;
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const struct TALER_EXCHANGE_DenomPublicKey *dki;
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struct TALER_EXCHANGE_DepositHandle *dh;
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struct GNUNET_CURL_Context *ctx;
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json_t *deposit_obj;
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CURL *eh;
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struct GNUNET_HashCode h_wire;
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struct TALER_Amount amount_without_fee;
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(void) GNUNET_TIME_round_abs (&wire_deadline);
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(void) GNUNET_TIME_round_abs (&refund_deadline);
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GNUNET_assert (refund_deadline.abs_value_us <= wire_deadline.abs_value_us);
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GNUNET_assert (GNUNET_YES ==
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MAH_handle_is_ready (exchange));
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/* initialize h_wire */
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GNUNET_assert (GNUNET_OK ==
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TALER_JSON_hash (wire_details,
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&h_wire));
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key_state = TALER_EXCHANGE_get_keys (exchange);
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dki = TALER_EXCHANGE_get_denomination_key (key_state,
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denom_pub);
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GNUNET_assert (NULL != dki);
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GNUNET_assert (GNUNET_SYSERR !=
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TALER_amount_subtract (&amount_without_fee,
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amount,
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&dki->fee_deposit));
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if (GNUNET_OK !=
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verify_signatures (dki,
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amount,
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&h_wire,
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h_contract,
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coin_pub,
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denom_sig,
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denom_pub,
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timestamp,
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transaction_id,
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merchant_pub,
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refund_deadline,
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coin_sig))
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{
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GNUNET_break_op (0);
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return NULL;
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}
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deposit_obj = json_pack ("{s:o, s:O," /* f/wire */
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" s:o, s:o," /* H_wire, H_contract */
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" s:o, s:o," /* coin_pub, denom_pub */
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" s:o, s:o," /* ub_sig, timestamp */
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" s:I, s:o," /* transaction id, merchant_pub */
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" s:o, s:o," /* refund_deadline, wire_deadline */
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" s:o}", /* coin_sig */
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"f", TALER_JSON_from_amount (amount),
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"wire", wire_details,
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"H_wire", GNUNET_JSON_from_data_auto (&h_wire),
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"H_contract", GNUNET_JSON_from_data_auto (h_contract),
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"coin_pub", GNUNET_JSON_from_data_auto (coin_pub),
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"denom_pub", GNUNET_JSON_from_rsa_public_key (denom_pub->rsa_public_key),
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"ub_sig", GNUNET_JSON_from_rsa_signature (denom_sig->rsa_signature),
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"timestamp", GNUNET_JSON_from_time_abs (timestamp),
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"transaction_id", (json_int_t) transaction_id,
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"merchant_pub", GNUNET_JSON_from_data_auto (merchant_pub),
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"refund_deadline", GNUNET_JSON_from_time_abs (refund_deadline),
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"wire_transfer_deadline", GNUNET_JSON_from_time_abs (wire_deadline),
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"coin_sig", GNUNET_JSON_from_data_auto (coin_sig)
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);
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|
||
dh = GNUNET_new (struct TALER_EXCHANGE_DepositHandle);
|
||
dh->exchange = exchange;
|
||
dh->cb = cb;
|
||
dh->cb_cls = cb_cls;
|
||
dh->url = MAH_path_to_url (exchange, "/deposit");
|
||
dh->depconf.purpose.size = htonl (sizeof (struct TALER_DepositConfirmationPS));
|
||
dh->depconf.purpose.purpose = htonl (TALER_SIGNATURE_EXCHANGE_CONFIRM_DEPOSIT);
|
||
dh->depconf.h_contract = *h_contract;
|
||
dh->depconf.h_wire = h_wire;
|
||
dh->depconf.transaction_id = GNUNET_htonll (transaction_id);
|
||
dh->depconf.timestamp = GNUNET_TIME_absolute_hton (timestamp);
|
||
dh->depconf.refund_deadline = GNUNET_TIME_absolute_hton (refund_deadline);
|
||
TALER_amount_hton (&dh->depconf.amount_without_fee,
|
||
&amount_without_fee);
|
||
dh->depconf.coin_pub = *coin_pub;
|
||
dh->depconf.merchant = *merchant_pub;
|
||
dh->amount_with_fee = *amount;
|
||
dh->coin_value = dki->value;
|
||
|
||
eh = curl_easy_init ();
|
||
GNUNET_assert (NULL != (dh->json_enc =
|
||
json_dumps (deposit_obj,
|
||
JSON_COMPACT)));
|
||
json_decref (deposit_obj);
|
||
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
|
||
"URL for deposit: `%s'\n",
|
||
dh->url);
|
||
GNUNET_assert (CURLE_OK ==
|
||
curl_easy_setopt (eh,
|
||
CURLOPT_URL,
|
||
dh->url));
|
||
GNUNET_assert (CURLE_OK ==
|
||
curl_easy_setopt (eh,
|
||
CURLOPT_POSTFIELDS,
|
||
dh->json_enc));
|
||
GNUNET_assert (CURLE_OK ==
|
||
curl_easy_setopt (eh,
|
||
CURLOPT_POSTFIELDSIZE,
|
||
strlen (dh->json_enc)));
|
||
ctx = MAH_handle_to_context (exchange);
|
||
dh->job = GNUNET_CURL_job_add (ctx,
|
||
eh,
|
||
GNUNET_YES,
|
||
&handle_deposit_finished,
|
||
dh);
|
||
return dh;
|
||
}
|
||
|
||
|
||
/**
|
||
* Cancel a deposit permission request. This function cannot be used
|
||
* on a request handle if a response is already served for it.
|
||
*
|
||
* @param deposit the deposit permission request handle
|
||
*/
|
||
void
|
||
TALER_EXCHANGE_deposit_cancel (struct TALER_EXCHANGE_DepositHandle *deposit)
|
||
{
|
||
if (NULL != deposit->job)
|
||
{
|
||
GNUNET_CURL_job_cancel (deposit->job);
|
||
deposit->job = NULL;
|
||
}
|
||
GNUNET_free (deposit->url);
|
||
GNUNET_free (deposit->json_enc);
|
||
GNUNET_free (deposit);
|
||
}
|
||
|
||
|
||
/* end of exchange_api_deposit.c */
|