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exchange/src/lib/exchange_api_wire.c

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/*
This file is part of TALER
Copyright (C) 2014-2022 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_wire.c
* @brief Implementation of the /wire 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_curl_lib.h>
#include "taler_exchange_service.h"
#include "taler_json_lib.h"
#include "taler_signatures.h"
#include "exchange_api_handle.h"
#include "exchange_api_curl_defaults.h"
/**
* @brief A Wire Handle
*/
struct TALER_EXCHANGE_WireHandle
{
/**
* The connection to exchange this request handle will use
*/
struct TALER_EXCHANGE_Handle *exchange;
/**
* The url for this request.
*/
char *url;
/**
* Handle for the request.
*/
struct GNUNET_CURL_Job *job;
/**
* Function to call with the result.
*/
TALER_EXCHANGE_WireCallback cb;
/**
* Closure for @a cb.
*/
void *cb_cls;
};
/**
* List of wire fees by method.
*/
struct FeeMap
{
/**
* Next entry in list.
*/
struct FeeMap *next;
/**
* Wire method this fee structure is for.
*/
char *method;
/**
* Array of wire fees, also linked list, but allocated
* only once.
*/
struct TALER_EXCHANGE_WireAggregateFees *fee_list;
};
/**
* Frees @a fm.
*
* @param fm memory to release
*/
static void
free_fees (struct FeeMap *fm)
{
while (NULL != fm)
{
struct FeeMap *fe = fm->next;
GNUNET_free (fm->fee_list);
GNUNET_free (fm->method);
GNUNET_free (fm);
fm = fe;
}
}
/**
* Parse wire @a fees and return map.
*
* @param fees json AggregateTransferFee to parse
* @return NULL on error
*/
static struct FeeMap *
parse_fees (json_t *fees)
{
struct FeeMap *fm = NULL;
const char *key;
json_t *fee_array;
json_object_foreach (fees, key, fee_array) {
struct FeeMap *fe = GNUNET_new (struct FeeMap);
unsigned int len;
unsigned int idx;
json_t *fee;
if (0 == (len = json_array_size (fee_array)))
{
GNUNET_free (fe);
continue; /* skip */
}
fe->method = GNUNET_strdup (key);
fe->next = fm;
fe->fee_list = GNUNET_new_array (len,
struct TALER_EXCHANGE_WireAggregateFees);
fm = fe;
json_array_foreach (fee_array, idx, fee)
{
struct TALER_EXCHANGE_WireAggregateFees *wa = &fe->fee_list[idx];
struct GNUNET_JSON_Specification spec[] = {
GNUNET_JSON_spec_fixed_auto ("sig",
&wa->master_sig),
TALER_JSON_spec_amount_any ("wire_fee",
&wa->fees.wire),
TALER_JSON_spec_amount_any ("wad_fee",
&wa->fees.wad),
TALER_JSON_spec_amount_any ("closing_fee",
&wa->fees.closing),
GNUNET_JSON_spec_timestamp ("start_date",
&wa->start_date),
GNUNET_JSON_spec_timestamp ("end_date",
&wa->end_date),
GNUNET_JSON_spec_end ()
};
if (GNUNET_OK !=
GNUNET_JSON_parse (fee,
spec,
NULL,
NULL))
{
GNUNET_break_op (0);
free_fees (fm);
return NULL;
}
if (idx + 1 < len)
wa->next = &fe->fee_list[idx + 1];
else
wa->next = NULL;
}
}
return fm;
}
/**
* Find fee by @a method.
*
* @param fm map to look in
* @param method key to look for
* @return NULL if fee is not specified in @a fm
*/
static const struct TALER_EXCHANGE_WireAggregateFees *
lookup_fee (const struct FeeMap *fm,
const char *method)
{
for (; NULL != fm; fm = fm->next)
if (0 == strcasecmp (fm->method,
method))
return fm->fee_list;
return NULL;
}
/**
* Function called when we're done processing the
* HTTP /wire request.
*
* @param cls the `struct TALER_EXCHANGE_WireHandle`
* @param response_code HTTP response code, 0 on error
* @param response parsed JSON result, NULL on error
*/
static void
handle_wire_finished (void *cls,
long response_code,
const void *response)
{
struct TALER_EXCHANGE_WireHandle *wh = cls;
const json_t *j = response;
struct TALER_EXCHANGE_HttpResponse hr = {
.reply = j,
.http_status = (unsigned int) response_code
};
TALER_LOG_DEBUG ("Checking raw /wire response\n");
wh->job = NULL;
switch (response_code)
{
case 0:
hr.ec = TALER_EC_GENERIC_INVALID_RESPONSE;
/* FIXME: Maybe we should only increment when we know it's a timeout? */
wh->exchange->wire_error_count++;
break;
case MHD_HTTP_OK:
{
json_t *accounts;
json_t *fees;
unsigned int num_accounts;
struct FeeMap *fm;
const struct TALER_EXCHANGE_Keys *key_state;
struct GNUNET_JSON_Specification spec[] = {
GNUNET_JSON_spec_json ("accounts",
&accounts),
GNUNET_JSON_spec_json ("fees",
&fees),
GNUNET_JSON_spec_end ()
};
wh->exchange->wire_error_count = 0;
if (GNUNET_OK !=
GNUNET_JSON_parse (j,
spec,
NULL, NULL))
{
/* bogus reply */
GNUNET_break_op (0);
hr.http_status = 0;
hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
break;
}
if (0 == (num_accounts = json_array_size (accounts)))
{
/* bogus reply */
GNUNET_break_op (0);
GNUNET_JSON_parse_free (spec);
hr.http_status = 0;
hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
break;
}
if (NULL == (fm = parse_fees (fees)))
{
/* bogus reply */
GNUNET_break_op (0);
GNUNET_JSON_parse_free (spec);
hr.http_status = 0;
hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
break;
}
key_state = TALER_EXCHANGE_get_keys (wh->exchange);
/* parse accounts */
{
struct TALER_EXCHANGE_WireAccount was[num_accounts];
for (unsigned int i = 0; i<num_accounts; i++)
{
struct TALER_EXCHANGE_WireAccount *wa = &was[i];
json_t *account;
struct GNUNET_JSON_Specification spec_account[] = {
GNUNET_JSON_spec_string ("payto_uri",
&wa->payto_uri),
GNUNET_JSON_spec_fixed_auto ("master_sig",
&wa->master_sig),
GNUNET_JSON_spec_end ()
};
char *method;
account = json_array_get (accounts,
i);
if (GNUNET_OK !=
TALER_JSON_exchange_wire_signature_check (account,
&key_state->master_pub))
{
/* bogus reply */
GNUNET_break_op (0);
hr.http_status = 0;
hr.ec = TALER_EC_EXCHANGE_WIRE_SIGNATURE_INVALID;
break;
}
if (GNUNET_OK !=
GNUNET_JSON_parse (account,
spec_account,
NULL, NULL))
{
/* bogus reply */
GNUNET_break_op (0);
hr.http_status = 0;
hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
break;
}
if (NULL == (method = TALER_payto_get_method (wa->payto_uri)))
{
/* bogus reply */
GNUNET_break_op (0);
hr.http_status = 0;
hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
break;
}
if (NULL == (wa->fees = lookup_fee (fm,
method)))
{
/* bogus reply */
GNUNET_break_op (0);
hr.http_status = 0;
hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
GNUNET_free (method);
break;
}
GNUNET_free (method);
} /* end 'for all accounts */
if ( (0 != response_code) &&
(NULL != wh->cb) )
{
wh->cb (wh->cb_cls,
&hr,
num_accounts,
was);
wh->cb = NULL;
}
} /* end of 'parse accounts */
free_fees (fm);
GNUNET_JSON_parse_free (spec);
} /* end of MHD_HTTP_OK */
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 */
hr.ec = TALER_JSON_get_error_code (j);
hr.hint = TALER_JSON_get_error_hint (j);
break;
case MHD_HTTP_NOT_FOUND:
/* Nothing really to verify, this should never
happen, we should pass the JSON reply to the application */
hr.ec = TALER_JSON_get_error_code (j);
hr.hint = TALER_JSON_get_error_hint (j);
break;
case MHD_HTTP_INTERNAL_SERVER_ERROR:
/* Server had an internal issue; we should retry, but this API
leaves this to the application */
hr.ec = TALER_JSON_get_error_code (j);
hr.hint = TALER_JSON_get_error_hint (j);
break;
default:
/* unexpected response code */
if (MHD_HTTP_GATEWAY_TIMEOUT == response_code)
wh->exchange->wire_error_count++;
GNUNET_break_op (0);
hr.ec = TALER_JSON_get_error_code (j);
hr.hint = TALER_JSON_get_error_hint (j);
GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
"Unexpected response code %u/%d for exchange wire\n",
(unsigned int) response_code,
(int) hr.ec);
break;
}
if (NULL != wh->cb)
wh->cb (wh->cb_cls,
&hr,
0,
NULL);
TALER_EXCHANGE_wire_cancel (wh);
}
/**
* Compute the network timeout for the next request to /wire.
*
* @param exchange the exchange handle
* @returns the timeout in seconds (for use by CURL)
*/
static long
get_wire_timeout_seconds (struct TALER_EXCHANGE_Handle *exchange)
{
return GNUNET_MIN (60,
5 + (1L << exchange->wire_error_count));
}
/**
* Obtain information about a exchange's wire instructions.
* A exchange may provide wire instructions for creating
* a reserve. The wire instructions also indicate
* which wire formats merchants may use with the exchange.
* This API is typically used by a wallet for wiring
* funds, and possibly by a merchant to determine
* supported wire formats.
*
* Note that while we return the (main) 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.
*
* @param exchange the exchange handle; the exchange must be ready to operate
* @param wire_cb the callback to call when a reply for this request is available
* @param wire_cb_cls closure for the above callback
* @return a handle for this request
*/
struct TALER_EXCHANGE_WireHandle *
TALER_EXCHANGE_wire (struct TALER_EXCHANGE_Handle *exchange,
TALER_EXCHANGE_WireCallback wire_cb,
void *wire_cb_cls)
{
struct TALER_EXCHANGE_WireHandle *wh;
struct GNUNET_CURL_Context *ctx;
CURL *eh;
if (GNUNET_YES !=
TEAH_handle_is_ready (exchange))
{
GNUNET_break (0);
return NULL;
}
wh = GNUNET_new (struct TALER_EXCHANGE_WireHandle);
wh->exchange = exchange;
wh->cb = wire_cb;
wh->cb_cls = wire_cb_cls;
wh->url = TEAH_path_to_url (exchange,
"/wire");
if (NULL == wh->url)
{
GNUNET_free (wh);
return NULL;
}
eh = TALER_EXCHANGE_curl_easy_get_ (wh->url);
if (NULL == eh)
{
GNUNET_break (0);
GNUNET_free (wh->url);
GNUNET_free (wh);
return NULL;
}
GNUNET_break (CURLE_OK ==
curl_easy_setopt (eh,
CURLOPT_TIMEOUT,
get_wire_timeout_seconds (wh->exchange)));
ctx = TEAH_handle_to_context (exchange);
wh->job = GNUNET_CURL_job_add_with_ct_json (ctx,
eh,
&handle_wire_finished,
wh);
return wh;
}
/**
* Cancel a wire information request. This function cannot be used
* on a request handle if a response is already served for it.
*
* @param wh the wire information request handle
*/
void
TALER_EXCHANGE_wire_cancel (struct TALER_EXCHANGE_WireHandle *wh)
{
if (NULL != wh->job)
{
GNUNET_CURL_job_cancel (wh->job);
wh->job = NULL;
}
GNUNET_free (wh->url);
GNUNET_free (wh);
}
/* end of exchange_api_wire.c */
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