417 lines
15 KiB
C
417 lines
15 KiB
C
/*
|
||
This file is part of TALER
|
||
Copyright (C) 2014, 2015, 2016 GNUnet e.V.
|
||
|
||
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 exchange-lib/exchange_api_refund.c
|
||
* @brief Implementation of the /refund request of the exchange's HTTP API
|
||
* @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_json_lib.h"
|
||
#include "taler_exchange_service.h"
|
||
#include "exchange_api_handle.h"
|
||
#include "taler_signatures.h"
|
||
#include "curl_defaults.h"
|
||
|
||
|
||
/**
|
||
* @brief A Refund Handle
|
||
*/
|
||
struct TALER_EXCHANGE_RefundHandle
|
||
{
|
||
|
||
/**
|
||
* The connection to exchange this request handle will use
|
||
*/
|
||
struct TALER_EXCHANGE_Handle *exchange;
|
||
|
||
/**
|
||
* The url for this request.
|
||
*/
|
||
char *url;
|
||
|
||
/**
|
||
* JSON encoding of the request to POST.
|
||
*/
|
||
char *json_enc;
|
||
|
||
/**
|
||
* Handle for the request.
|
||
*/
|
||
struct GNUNET_CURL_Job *job;
|
||
|
||
/**
|
||
* Function to call with the result.
|
||
*/
|
||
TALER_EXCHANGE_RefundResultCallback cb;
|
||
|
||
/**
|
||
* Closure for @a cb.
|
||
*/
|
||
void *cb_cls;
|
||
|
||
/**
|
||
* Information the exchange should sign in response.
|
||
*/
|
||
struct TALER_RefundConfirmationPS depconf;
|
||
|
||
};
|
||
|
||
|
||
/**
|
||
* Verify that the signature on the "200 OK" response
|
||
* from the exchange is valid.
|
||
*
|
||
* @param rh refund handle
|
||
* @param json json reply with the signature
|
||
* @param[out] exchange_pub set to the exchange's public key
|
||
* @return #GNUNET_OK if the signature is valid, #GNUNET_SYSERR if not
|
||
*/
|
||
static int
|
||
verify_refund_signature_ok (const struct TALER_EXCHANGE_RefundHandle *rh,
|
||
const json_t *json,
|
||
struct TALER_ExchangePublicKeyP *exchange_pub)
|
||
{
|
||
struct TALER_ExchangeSignatureP exchange_sig;
|
||
const struct TALER_EXCHANGE_Keys *key_state;
|
||
struct GNUNET_JSON_Specification spec[] = {
|
||
GNUNET_JSON_spec_fixed_auto ("sig", &exchange_sig),
|
||
GNUNET_JSON_spec_fixed_auto ("pub", exchange_pub),
|
||
GNUNET_JSON_spec_end()
|
||
};
|
||
|
||
if (GNUNET_OK !=
|
||
GNUNET_JSON_parse (json,
|
||
spec,
|
||
NULL, NULL))
|
||
{
|
||
GNUNET_break_op (0);
|
||
return GNUNET_SYSERR;
|
||
}
|
||
key_state = TALER_EXCHANGE_get_keys (rh->exchange);
|
||
if (GNUNET_OK !=
|
||
TALER_EXCHANGE_test_signing_key (key_state,
|
||
exchange_pub))
|
||
{
|
||
GNUNET_break_op (0);
|
||
return GNUNET_SYSERR;
|
||
}
|
||
if (GNUNET_OK !=
|
||
GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_EXCHANGE_CONFIRM_REFUND,
|
||
&rh->depconf.purpose,
|
||
&exchange_sig.eddsa_signature,
|
||
&exchange_pub->eddsa_pub))
|
||
{
|
||
GNUNET_break_op (0);
|
||
return GNUNET_SYSERR;
|
||
}
|
||
return GNUNET_OK;
|
||
}
|
||
|
||
|
||
/**
|
||
* Function called when we're done processing the
|
||
* HTTP /refund request.
|
||
*
|
||
* @param cls the `struct TALER_EXCHANGE_RefundHandle`
|
||
* @param response_code HTTP response code, 0 on error
|
||
* @param response parsed JSON result, NULL on error
|
||
*/
|
||
static void
|
||
handle_refund_finished (void *cls,
|
||
long response_code,
|
||
const void *response)
|
||
{
|
||
struct TALER_EXCHANGE_RefundHandle *rh = cls;
|
||
struct TALER_ExchangePublicKeyP exchange_pub;
|
||
struct TALER_ExchangePublicKeyP *ep = NULL;
|
||
const json_t *j = response;
|
||
|
||
rh->job = NULL;
|
||
switch (response_code)
|
||
{
|
||
case 0:
|
||
break;
|
||
case MHD_HTTP_OK:
|
||
if (GNUNET_OK !=
|
||
verify_refund_signature_ok (rh,
|
||
j,
|
||
&exchange_pub))
|
||
{
|
||
GNUNET_break_op (0);
|
||
response_code = 0;
|
||
}
|
||
else
|
||
{
|
||
ep = &exchange_pub;
|
||
}
|
||
break;
|
||
case MHD_HTTP_BAD_REQUEST:
|
||
/* This should never happen, either us or the exchange is buggy
|
||
(or API version conflict); just pass JSON reply to the application */
|
||
break;
|
||
case MHD_HTTP_UNAUTHORIZED:
|
||
/* Nothing really to verify, exchange says one of the signatures is
|
||
invalid; as we checked them, this should never happen, we
|
||
should pass the JSON reply to the application */
|
||
break;
|
||
case MHD_HTTP_NOT_FOUND:
|
||
/* Nothing really to verify, this should never
|
||
happen, we should pass the JSON reply to the application */
|
||
break;
|
||
case MHD_HTTP_GONE:
|
||
/* Kind of normal: the money was already sent to the merchant
|
||
(it was too late for the refund). */
|
||
break;
|
||
case MHD_HTTP_PRECONDITION_FAILED:
|
||
/* Client request was inconsistent; might be a currency missmatch
|
||
problem. */
|
||
break;
|
||
case MHD_HTTP_CONFLICT:
|
||
/* Two refund requests were made about the same deposit, but
|
||
carrying different refund transaction ids. */
|
||
break;
|
||
case MHD_HTTP_INTERNAL_SERVER_ERROR:
|
||
/* Server had an internal issue; we should retry, but this API
|
||
leaves this to the application */
|
||
break;
|
||
default:
|
||
/* unexpected response code */
|
||
GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
|
||
"Unexpected response code %u\n",
|
||
(unsigned int) response_code);
|
||
GNUNET_break (0);
|
||
response_code = 0;
|
||
break;
|
||
}
|
||
rh->cb (rh->cb_cls,
|
||
response_code,
|
||
TALER_JSON_get_error_code (j),
|
||
ep,
|
||
j);
|
||
TALER_EXCHANGE_refund_cancel (rh);
|
||
}
|
||
|
||
|
||
/**
|
||
* Submit a refund request to the exchange and get the exchange's
|
||
* response. This API is used by a merchant. Note that
|
||
* while we return the response verbatim to the caller for further
|
||
* processing, we do already verify that the response is well-formed
|
||
* (i.e. that signatures included in the response are all valid). If
|
||
* the exchange's reply is not well-formed, we return an HTTP status code
|
||
* of zero to @a cb.
|
||
*
|
||
* The @a exchange must be ready to operate (i.e. have
|
||
* finished processing the /keys reply). If this check fails, we do
|
||
* NOT initiate the transaction with the exchange and instead return NULL.
|
||
*
|
||
* @param exchange the exchange handle; the exchange must be ready to operate
|
||
* @param amount the amount to be refunded; must be larger than the refund fee
|
||
* (as that fee is still being subtracted), and smaller than the amount
|
||
* (with deposit fee) of the original deposit contribution of this coin
|
||
* @param refund_fee fee applicable to this coin for the refund
|
||
* @param h_contract_terms hash of the contact of the merchant with the customer that is being refunded
|
||
* @param coin_pub coin’s public key of the coin from the original deposit operation
|
||
* @param rtransaction_id transaction id for the transaction between merchant and customer (of refunding operation);
|
||
* this is needed as we may first do a partial refund and later a full refund. If both
|
||
* refunds are also over the same amount, we need the @a rtransaction_id to make the disjoint
|
||
* refund requests different (as requests are idempotent and otherwise the 2nd refund might not work).
|
||
* @param merchant_priv the private key of the merchant, used to generate signature for refund request
|
||
* @param cb the callback to call when a reply for this request is available
|
||
* @param cb_cls closure for the above callback
|
||
* @return a handle for this request; NULL if the inputs are invalid (i.e.
|
||
* signatures fail to verify). In this case, the callback is not called.
|
||
*/
|
||
struct TALER_EXCHANGE_RefundHandle *
|
||
TALER_EXCHANGE_refund (struct TALER_EXCHANGE_Handle *exchange,
|
||
const struct TALER_Amount *amount,
|
||
const struct TALER_Amount *refund_fee,
|
||
const struct GNUNET_HashCode *h_contract_terms,
|
||
const struct TALER_CoinSpendPublicKeyP *coin_pub,
|
||
uint64_t rtransaction_id,
|
||
const struct TALER_MerchantPrivateKeyP *merchant_priv,
|
||
TALER_EXCHANGE_RefundResultCallback cb,
|
||
void *cb_cls)
|
||
{
|
||
struct TALER_RefundRequestPS rr;
|
||
struct TALER_MerchantSignatureP merchant_sig;
|
||
|
||
GNUNET_assert (GNUNET_YES ==
|
||
TEAH_handle_is_ready (exchange));
|
||
rr.purpose.purpose = htonl (TALER_SIGNATURE_MERCHANT_REFUND);
|
||
rr.purpose.size = htonl (sizeof (struct TALER_RefundRequestPS));
|
||
rr.h_contract_terms = *h_contract_terms;
|
||
rr.coin_pub = *coin_pub;
|
||
GNUNET_CRYPTO_eddsa_key_get_public (&merchant_priv->eddsa_priv,
|
||
&rr.merchant.eddsa_pub);
|
||
rr.rtransaction_id = GNUNET_htonll (rtransaction_id);
|
||
TALER_amount_hton (&rr.refund_amount,
|
||
amount);
|
||
TALER_amount_hton (&rr.refund_fee,
|
||
refund_fee);
|
||
GNUNET_assert (GNUNET_OK ==
|
||
GNUNET_CRYPTO_eddsa_sign (&merchant_priv->eddsa_priv,
|
||
&rr.purpose,
|
||
&merchant_sig.eddsa_sig));
|
||
return TALER_EXCHANGE_refund2 (exchange,
|
||
amount,
|
||
refund_fee,
|
||
h_contract_terms,
|
||
coin_pub,
|
||
rtransaction_id,
|
||
&rr.merchant,
|
||
&merchant_sig,
|
||
cb,
|
||
cb_cls);
|
||
}
|
||
|
||
|
||
/**
|
||
* Submit a refund request to the exchange and get the exchange's
|
||
* response. This API is used by a merchant. Note that
|
||
* while we return the response verbatim to the caller for further
|
||
* processing, we do already verify that the response is well-formed
|
||
* (i.e. that signatures included in the response are all valid). If
|
||
* the exchange's reply is not well-formed, we return an HTTP status code
|
||
* of zero to @a cb.
|
||
*
|
||
* The @a exchange must be ready to operate (i.e. have
|
||
* finished processing the /keys reply). If this check fails, we do
|
||
* NOT initiate the transaction with the exchange and instead return NULL.
|
||
*
|
||
* @param exchange the exchange handle; the exchange must be ready to operate
|
||
* @param amount the amount to be refunded; must be larger than the refund fee
|
||
* (as that fee is still being subtracted), and smaller than the amount
|
||
* (with deposit fee) of the original deposit contribution of this coin
|
||
* @param refund_fee fee applicable to this coin for the refund
|
||
* @param h_contract_terms hash of the contact of the merchant with the customer that is being refunded
|
||
* @param coin_pub coin’s public key of the coin from the original deposit operation
|
||
* @param rtransaction_id transaction id for the transaction between merchant and customer (of refunding operation);
|
||
* this is needed as we may first do a partial refund and later a full refund. If both
|
||
* refunds are also over the same amount, we need the @a rtransaction_id to make the disjoint
|
||
* refund requests different (as requests are idempotent and otherwise the 2nd refund might not work).
|
||
* @param merchant_pub public key of the merchant
|
||
* @param merchant_sig signature affirming the refund from the merchant
|
||
* @param cb the callback to call when a reply for this request is available
|
||
* @param cb_cls closure for the above callback
|
||
* @return a handle for this request; NULL if the inputs are invalid (i.e.
|
||
* signatures fail to verify). In this case, the callback is not called.
|
||
*/
|
||
struct TALER_EXCHANGE_RefundHandle *
|
||
TALER_EXCHANGE_refund2 (struct TALER_EXCHANGE_Handle *exchange,
|
||
const struct TALER_Amount *amount,
|
||
const struct TALER_Amount *refund_fee,
|
||
const struct GNUNET_HashCode *h_contract_terms,
|
||
const struct TALER_CoinSpendPublicKeyP *coin_pub,
|
||
uint64_t rtransaction_id,
|
||
const struct TALER_MerchantPublicKeyP *merchant_pub,
|
||
const struct TALER_MerchantSignatureP *merchant_sig,
|
||
TALER_EXCHANGE_RefundResultCallback cb,
|
||
void *cb_cls)
|
||
{
|
||
struct TALER_EXCHANGE_RefundHandle *rh;
|
||
struct GNUNET_CURL_Context *ctx;
|
||
json_t *refund_obj;
|
||
CURL *eh;
|
||
|
||
refund_obj = json_pack ("{s:o, s:o," /* amount/fee */
|
||
" s:o, s:o," /* h_contract_terms, coin_pub */
|
||
" s:I," /* rtransaction id */
|
||
" s:o, s:o}", /* merchant_pub, merchant_sig */
|
||
"refund_amount", TALER_JSON_from_amount (amount),
|
||
"refund_fee", TALER_JSON_from_amount (refund_fee),
|
||
"h_contract_terms", GNUNET_JSON_from_data_auto (h_contract_terms),
|
||
"coin_pub", GNUNET_JSON_from_data_auto (coin_pub),
|
||
"rtransaction_id", (json_int_t) rtransaction_id,
|
||
"merchant_pub", GNUNET_JSON_from_data_auto (merchant_pub),
|
||
"merchant_sig", GNUNET_JSON_from_data_auto (merchant_sig)
|
||
);
|
||
if (NULL == refund_obj)
|
||
{
|
||
GNUNET_break (0);
|
||
return NULL;
|
||
}
|
||
|
||
rh = GNUNET_new (struct TALER_EXCHANGE_RefundHandle);
|
||
rh->exchange = exchange;
|
||
rh->cb = cb;
|
||
rh->cb_cls = cb_cls;
|
||
rh->url = TEAH_path_to_url (exchange, "/refund");
|
||
rh->depconf.purpose.size = htonl (sizeof (struct TALER_RefundConfirmationPS));
|
||
rh->depconf.purpose.purpose = htonl (TALER_SIGNATURE_EXCHANGE_CONFIRM_REFUND);
|
||
rh->depconf.h_contract_terms = *h_contract_terms;
|
||
rh->depconf.coin_pub = *coin_pub;
|
||
rh->depconf.merchant = *merchant_pub;
|
||
rh->depconf.rtransaction_id = GNUNET_htonll (rtransaction_id);
|
||
TALER_amount_hton (&rh->depconf.refund_amount,
|
||
amount);
|
||
TALER_amount_hton (&rh->depconf.refund_fee,
|
||
refund_fee);
|
||
|
||
eh = TEL_curl_easy_get (rh->url);
|
||
GNUNET_assert (NULL != (rh->json_enc =
|
||
json_dumps (refund_obj,
|
||
JSON_COMPACT)));
|
||
json_decref (refund_obj);
|
||
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
|
||
"URL for refund: `%s'\n",
|
||
rh->url);
|
||
GNUNET_assert (CURLE_OK ==
|
||
curl_easy_setopt (eh,
|
||
CURLOPT_POSTFIELDS,
|
||
rh->json_enc));
|
||
GNUNET_assert (CURLE_OK ==
|
||
curl_easy_setopt (eh,
|
||
CURLOPT_POSTFIELDSIZE,
|
||
strlen (rh->json_enc)));
|
||
ctx = TEAH_handle_to_context (exchange);
|
||
rh->job = GNUNET_CURL_job_add (ctx,
|
||
eh,
|
||
GNUNET_YES,
|
||
&handle_refund_finished,
|
||
rh);
|
||
return rh;
|
||
}
|
||
|
||
|
||
/**
|
||
* Cancel a refund permission request. This function cannot be used
|
||
* on a request handle if a response is already served for it.
|
||
*
|
||
* @param refund the refund permission request handle
|
||
*/
|
||
void
|
||
TALER_EXCHANGE_refund_cancel (struct TALER_EXCHANGE_RefundHandle *refund)
|
||
{
|
||
if (NULL != refund->job)
|
||
{
|
||
GNUNET_CURL_job_cancel (refund->job);
|
||
refund->job = NULL;
|
||
}
|
||
GNUNET_free (refund->url);
|
||
GNUNET_free (refund->json_enc);
|
||
GNUNET_free (refund);
|
||
}
|
||
|
||
|
||
/* end of exchange_api_refund.c */
|