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exchange/src/exchange-lib/exchange_api_handle.c

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/*
This file is part of TALER
Copyright (C) 2014-2017 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_handle.c
* @brief Implementation of the "handle" component of the exchange's HTTP API
* @author Sree Harsha Totakura <sreeharsha@totakura.in>
* @author Christian Grothoff
*/
#include "platform.h"
#include <curl/curl.h>
#include <microhttpd.h>
#include <gnunet/gnunet_curl_lib.h>
#include "taler_json_lib.h"
#include "taler_exchange_service.h"
#include "taler_signatures.h"
#include "exchange_api_handle.h"
/**
* Which revision of the Taler protocol is implemented
* by this library? Used to determine compatibility.
*/
#define TALER_PROTOCOL_CURRENT 0
/**
* How many revisions back are we compatible to?
*/
#define TALER_PROTOCOL_AGE 0
/**
* Log error related to CURL operations.
*
* @param type log level
* @param function which function failed to run
* @param code what was the curl error code
*/
#define CURL_STRERROR(type, function, code) \
GNUNET_log (type, "Curl function `%s' has failed at `%s:%d' with error: %s", \
function, __FILE__, __LINE__, curl_easy_strerror (code));
/**
* Stages of initialization for the `struct TALER_EXCHANGE_Handle`
*/
enum ExchangeHandleState
{
/**
* Just allocated.
*/
MHS_INIT = 0,
/**
* Obtained the exchange's certification data and keys.
*/
MHS_CERT = 1,
/**
* Failed to initialize (fatal).
*/
MHS_FAILED = 2
};
/**
* Data for the request to get the /keys of a exchange.
*/
struct KeysRequest;
/**
* Handle to the exchange
*/
struct TALER_EXCHANGE_Handle
{
/**
* The context of this handle
*/
struct GNUNET_CURL_Context *ctx;
/**
* The URL of the exchange (i.e. "http://exchange.taler.net/")
*/
char *url;
/**
* Function to call with the exchange's certification data,
* NULL if this has already been done.
*/
TALER_EXCHANGE_CertificationCallback cert_cb;
/**
* Closure to pass to @e cert_cb.
*/
void *cert_cb_cls;
/**
* Data for the request to get the /keys of a exchange,
* NULL once we are past stage #MHS_INIT.
*/
struct KeysRequest *kr;
/**
* Key data of the exchange, only valid if
* @e handshake_complete is past stage #MHS_CERT.
*/
struct TALER_EXCHANGE_Keys key_data;
/**
* When does @e key_data expire?
*/
struct GNUNET_TIME_Absolute key_data_expiration;
/**
* Raw key data of the exchange, only valid if
* @e handshake_complete is past stage #MHS_CERT.
*/
json_t *key_data_raw;
/**
* Stage of the exchange's initialization routines.
*/
enum ExchangeHandleState state;
};
/* ***************** Internal /keys fetching ************* */
/**
* Data for the request to get the /keys of a exchange.
*/
struct KeysRequest
{
/**
* The connection to exchange this request handle will use
*/
struct TALER_EXCHANGE_Handle *exchange;
/**
* The url for this handle
*/
char *url;
/**
* Entry for this request with the `struct GNUNET_CURL_Context`.
*/
struct GNUNET_CURL_Job *job;
/**
* Expiration time according to "Expire:" header.
* 0 if not provided by the server.
*/
struct GNUNET_TIME_Absolute expire;
};
/**
* Release memory occupied by a keys request.
* Note that this does not cancel the request
* itself.
*
* @param kr request to free
*/
static void
free_keys_request (struct KeysRequest *kr)
{
GNUNET_free (kr->url);
GNUNET_free (kr);
}
#define EXITIF(cond) \
do { \
if (cond) { GNUNET_break (0); goto EXITIF_exit; } \
} while (0)
/**
* Parse a exchange's signing key encoded in JSON.
*
* @param[out] sign_key where to return the result
* @param[in] sign_key_obj json to parse
* @param master_key master key to use to verify signature
* @return #GNUNET_OK if all is fine, #GNUNET_SYSERR if the signature is
* invalid or the json malformed.
*/
static int
parse_json_signkey (struct TALER_EXCHANGE_SigningPublicKey *sign_key,
json_t *sign_key_obj,
const struct TALER_MasterPublicKeyP *master_key)
{
struct TALER_ExchangeSigningKeyValidityPS sign_key_issue;
struct GNUNET_CRYPTO_EddsaSignature sig;
struct GNUNET_TIME_Absolute valid_from;
struct GNUNET_TIME_Absolute valid_until;
struct GNUNET_TIME_Absolute valid_legal;
struct GNUNET_JSON_Specification spec[] = {
GNUNET_JSON_spec_fixed_auto ("master_sig",
&sig),
GNUNET_JSON_spec_fixed_auto ("key",
&sign_key_issue.signkey_pub),
GNUNET_JSON_spec_absolute_time ("stamp_start",
&valid_from),
GNUNET_JSON_spec_absolute_time ("stamp_expire",
&valid_until),
GNUNET_JSON_spec_absolute_time ("stamp_end",
&valid_legal),
GNUNET_JSON_spec_end()
};
if (GNUNET_OK !=
GNUNET_JSON_parse (sign_key_obj,
spec,
NULL, NULL))
{
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
sign_key_issue.purpose.purpose = htonl (TALER_SIGNATURE_MASTER_SIGNING_KEY_VALIDITY);
sign_key_issue.purpose.size =
htonl (sizeof (struct TALER_ExchangeSigningKeyValidityPS)
- offsetof (struct TALER_ExchangeSigningKeyValidityPS,
purpose));
sign_key_issue.master_public_key = *master_key;
sign_key_issue.start = GNUNET_TIME_absolute_hton (valid_from);
sign_key_issue.expire = GNUNET_TIME_absolute_hton (valid_until);
sign_key_issue.end = GNUNET_TIME_absolute_hton (valid_legal);
if (GNUNET_OK !=
GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_MASTER_SIGNING_KEY_VALIDITY,
&sign_key_issue.purpose,
&sig,
&master_key->eddsa_pub))
{
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
sign_key->valid_from = valid_from;
sign_key->valid_until = valid_until;
sign_key->key = sign_key_issue.signkey_pub;
return GNUNET_OK;
}
/**
* Parse a exchange's denomination key encoded in JSON.
*
* @param[out] denom_key where to return the result
* @param[in] denom_key_obj json to parse
* @param master_key master key to use to verify signature
* @param hash_context where to accumulate data for signature verification
* @return #GNUNET_OK if all is fine, #GNUNET_SYSERR if the signature is
* invalid or the json malformed.
*/
static int
parse_json_denomkey (struct TALER_EXCHANGE_DenomPublicKey *denom_key,
json_t *denom_key_obj,
struct TALER_MasterPublicKeyP *master_key,
struct GNUNET_HashContext *hash_context)
{
struct GNUNET_TIME_Absolute valid_from;
struct GNUNET_TIME_Absolute withdraw_valid_until;
struct GNUNET_TIME_Absolute expire_deposit;
struct GNUNET_TIME_Absolute expire_legal;
struct TALER_Amount value;
struct TALER_Amount fee_withdraw;
struct TALER_Amount fee_deposit;
struct TALER_Amount fee_refresh;
struct TALER_Amount fee_refund;
struct TALER_DenominationKeyValidityPS denom_key_issue;
struct GNUNET_CRYPTO_RsaPublicKey *pk;
struct GNUNET_CRYPTO_EddsaSignature sig;
struct GNUNET_JSON_Specification spec[] = {
GNUNET_JSON_spec_fixed_auto ("master_sig",
&sig),
GNUNET_JSON_spec_absolute_time ("stamp_expire_deposit",
&expire_deposit),
GNUNET_JSON_spec_absolute_time ("stamp_expire_withdraw",
&withdraw_valid_until),
GNUNET_JSON_spec_absolute_time ("stamp_start",
&valid_from),
GNUNET_JSON_spec_absolute_time ("stamp_expire_legal",
&expire_legal),
TALER_JSON_spec_amount ("value",
&value),
TALER_JSON_spec_amount ("fee_withdraw",
&fee_withdraw),
TALER_JSON_spec_amount ("fee_deposit",
&fee_deposit),
TALER_JSON_spec_amount ("fee_refresh",
&fee_refresh),
TALER_JSON_spec_amount ("fee_refund",
&fee_refund),
GNUNET_JSON_spec_rsa_public_key ("denom_pub",
&pk),
GNUNET_JSON_spec_end()
};
if (GNUNET_OK !=
GNUNET_JSON_parse (denom_key_obj,
spec, NULL, NULL))
{
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
memset (&denom_key_issue, 0, sizeof (denom_key_issue));
GNUNET_CRYPTO_rsa_public_key_hash (pk,
&denom_key_issue.denom_hash);
denom_key_issue.purpose.purpose
= htonl (TALER_SIGNATURE_MASTER_DENOMINATION_KEY_VALIDITY);
denom_key_issue.purpose.size
= htonl (sizeof (struct TALER_DenominationKeyValidityPS));
denom_key_issue.master = *master_key;
denom_key_issue.start = GNUNET_TIME_absolute_hton (valid_from);
denom_key_issue.expire_withdraw = GNUNET_TIME_absolute_hton (withdraw_valid_until);
denom_key_issue.expire_deposit = GNUNET_TIME_absolute_hton (expire_deposit);
denom_key_issue.expire_legal = GNUNET_TIME_absolute_hton (expire_legal);
TALER_amount_hton (&denom_key_issue.value,
&value);
TALER_amount_hton (&denom_key_issue.fee_withdraw,
&fee_withdraw);
TALER_amount_hton (&denom_key_issue.fee_deposit,
&fee_deposit);
TALER_amount_hton (&denom_key_issue.fee_refresh,
&fee_refresh);
TALER_amount_hton (&denom_key_issue.fee_refund,
&fee_refund);
EXITIF (GNUNET_SYSERR ==
GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_MASTER_DENOMINATION_KEY_VALIDITY,
&denom_key_issue.purpose,
&sig,
&master_key->eddsa_pub));
GNUNET_CRYPTO_hash_context_read (hash_context,
&denom_key_issue.denom_hash,
sizeof (struct GNUNET_HashCode));
denom_key->key.rsa_public_key = pk;
denom_key->h_key = denom_key_issue.denom_hash;
denom_key->valid_from = valid_from;
denom_key->withdraw_valid_until = withdraw_valid_until;
denom_key->expire_deposit = expire_deposit;
denom_key->expire_legal = expire_legal;
denom_key->value = value;
denom_key->fee_withdraw = fee_withdraw;
denom_key->fee_deposit = fee_deposit;
denom_key->fee_refresh = fee_refresh;
denom_key->fee_refund = fee_refund;
return GNUNET_OK;
EXITIF_exit:
GNUNET_JSON_parse_free (spec);
return GNUNET_SYSERR;
}
/**
* Parse a exchange's auditor information encoded in JSON.
*
* @param[out] auditor where to return the result
* @param[in] auditor_obj json to parse
* @param key_data information about denomination keys
* @return #GNUNET_OK if all is fine, #GNUNET_SYSERR if the signature is
* invalid or the json malformed.
*/
static int
parse_json_auditor (struct TALER_EXCHANGE_AuditorInformation *auditor,
json_t *auditor_obj,
const struct TALER_EXCHANGE_Keys *key_data)
{
json_t *keys;
json_t *key;
unsigned int len;
unsigned int off;
unsigned int i;
const char *auditor_url;
struct TALER_ExchangeKeyValidityPS kv;
struct GNUNET_JSON_Specification spec[] = {
GNUNET_JSON_spec_fixed_auto ("auditor_pub",
&auditor->auditor_pub),
GNUNET_JSON_spec_string ("auditor_url",
&auditor_url),
GNUNET_JSON_spec_json ("denomination_keys",
&keys),
GNUNET_JSON_spec_end()
};
if (GNUNET_OK !=
GNUNET_JSON_parse (auditor_obj,
spec,
NULL, NULL))
{
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
auditor->auditor_url = GNUNET_strdup (auditor_url);
kv.purpose.purpose = htonl (TALER_SIGNATURE_AUDITOR_EXCHANGE_KEYS);
kv.purpose.size = htonl (sizeof (struct TALER_ExchangeKeyValidityPS));
GNUNET_CRYPTO_hash (auditor_url,
strlen (auditor_url) + 1,
&kv.auditor_url_hash);
kv.master = key_data->master_pub;
len = json_array_size (keys);
auditor->denom_keys = GNUNET_new_array (len,
const struct TALER_EXCHANGE_DenomPublicKey *);
i = 0;
off = 0;
json_array_foreach (keys, i, key) {
struct TALER_AuditorSignatureP auditor_sig;
struct GNUNET_HashCode denom_h;
const struct TALER_EXCHANGE_DenomPublicKey *dk;
struct GNUNET_JSON_Specification kspec[] = {
GNUNET_JSON_spec_fixed_auto ("denom_pub_h",
&denom_h),
GNUNET_JSON_spec_fixed_auto ("auditor_sig",
&auditor_sig),
GNUNET_JSON_spec_end()
};
if (GNUNET_OK !=
GNUNET_JSON_parse (key,
kspec,
NULL, NULL))
{
GNUNET_break_op (0);
continue;
}
dk = NULL;
for (unsigned int j=0;j<key_data->num_denom_keys;j++)
{
if (0 == memcmp (&denom_h,
&key_data->denom_keys[j].h_key,
sizeof (struct GNUNET_HashCode)))
{
dk = &key_data->denom_keys[j];
break;
}
}
if (NULL == dk)
{
GNUNET_break_op (0);
continue;
}
kv.start = GNUNET_TIME_absolute_hton (dk->valid_from);
kv.expire_withdraw = GNUNET_TIME_absolute_hton (dk->withdraw_valid_until);
kv.expire_deposit = GNUNET_TIME_absolute_hton (dk->expire_deposit);
kv.expire_legal = GNUNET_TIME_absolute_hton (dk->expire_legal);
TALER_amount_hton (&kv.value,
&dk->value);
TALER_amount_hton (&kv.fee_withdraw,
&dk->fee_withdraw);
TALER_amount_hton (&kv.fee_deposit,
&dk->fee_deposit);
TALER_amount_hton (&kv.fee_refresh,
&dk->fee_refresh);
TALER_amount_hton (&kv.fee_refund,
&dk->fee_refund);
kv.denom_hash = dk->h_key;
if (GNUNET_OK !=
GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_AUDITOR_EXCHANGE_KEYS,
&kv.purpose,
&auditor_sig.eddsa_sig,
&auditor->auditor_pub.eddsa_pub))
{
GNUNET_break_op (0);
GNUNET_JSON_parse_free (spec);
return GNUNET_SYSERR;
}
auditor->denom_keys[off] = dk;
off++;
}
auditor->num_denom_keys = off;
GNUNET_JSON_parse_free (spec);
return GNUNET_OK;
}
/**
* Decode the JSON in @a resp_obj from the /keys response and store the data
* in the @a key_data.
*
* @param[in] resp_obj JSON object to parse
* @param[out] key_data where to store the results we decoded
* @param[out] where to store version compatibility data
* @return #GNUNET_OK on success, #GNUNET_SYSERR on error (malformed JSON)
*/
static int
decode_keys_json (const json_t *resp_obj,
struct TALER_EXCHANGE_Keys *key_data,
enum TALER_EXCHANGE_VersionCompatibility *vc)
{
struct GNUNET_TIME_Absolute list_issue_date;
struct TALER_ExchangeSignatureP sig;
struct TALER_ExchangeKeySetPS ks;
struct GNUNET_HashContext *hash_context;
struct TALER_ExchangePublicKeyP pub;
unsigned int age;
unsigned int revision;
unsigned int current;
memset (key_data,
0,
sizeof (struct TALER_EXCHANGE_Keys));
if (JSON_OBJECT != json_typeof (resp_obj))
return GNUNET_SYSERR;
/* check the version */
{
const char *ver;
struct GNUNET_JSON_Specification spec[] = {
GNUNET_JSON_spec_string ("version",
&ver),
GNUNET_JSON_spec_end()
};
EXITIF (GNUNET_OK !=
GNUNET_JSON_parse (resp_obj,
spec,
NULL, NULL));
if (3 != sscanf (ver,
"%u:%u:%u",
&current,
&revision,
&age))
{
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
*vc = TALER_EXCHANGE_VC_MATCH;
if (TALER_PROTOCOL_CURRENT < current)
{
*vc |= TALER_EXCHANGE_VC_NEWER;
if (TALER_PROTOCOL_CURRENT < current - age)
*vc |= TALER_EXCHANGE_VC_INCOMPATIBLE;
}
if (TALER_PROTOCOL_CURRENT > current)
{
*vc |= TALER_EXCHANGE_VC_OLDER;
if (TALER_PROTOCOL_CURRENT - TALER_PROTOCOL_AGE > current)
*vc |= TALER_EXCHANGE_VC_INCOMPATIBLE;
}
key_data->version = GNUNET_strdup (ver);
}
/* parse the master public key and issue date of the response */
hash_context = GNUNET_CRYPTO_hash_context_start ();
{
struct GNUNET_JSON_Specification spec[] = {
GNUNET_JSON_spec_fixed_auto ("master_public_key",
&key_data->master_pub),
GNUNET_JSON_spec_fixed_auto ("eddsa_sig",
&sig),
GNUNET_JSON_spec_fixed_auto ("eddsa_pub",
&pub),
GNUNET_JSON_spec_absolute_time ("list_issue_date",
&list_issue_date),
GNUNET_JSON_spec_end()
};
EXITIF (GNUNET_OK !=
GNUNET_JSON_parse (resp_obj,
spec,
NULL, NULL));
}
/* parse the signing keys */
{
json_t *sign_keys_array;
json_t *sign_key_obj;
unsigned int index;
EXITIF (NULL == (sign_keys_array =
json_object_get (resp_obj,
"signkeys")));
EXITIF (JSON_ARRAY != json_typeof (sign_keys_array));
index = 0;
json_array_foreach (sign_keys_array, index, sign_key_obj) {
struct TALER_EXCHANGE_SigningPublicKey sk;
bool found = false;
EXITIF (GNUNET_SYSERR ==
parse_json_signkey (&sk,
sign_key_obj,
&key_data->master_pub));
for (unsigned int j=0;j<key_data->num_sign_keys;j++)
{
if (0 == memcmp (&sk,
&key_data->sign_keys[j],
sizeof (sk)))
{
found = true;
break;
}
}
if (found)
{
/* 0:0:0 did not support /keys cherry picking */
GNUNET_break_op (0 == current);
continue;
}
if (key_data->sign_keys_size == key_data->num_sign_keys)
GNUNET_array_grow (key_data->sign_keys,
key_data->sign_keys_size,
key_data->sign_keys_size * 2 + 2);
key_data->sign_keys[key_data->num_sign_keys++] = sk;
}
}
/* parse the denomination keys */
{
json_t *denom_keys_array;
json_t *denom_key_obj;
unsigned int index;
EXITIF (NULL == (denom_keys_array =
json_object_get (resp_obj, "denoms")));
EXITIF (JSON_ARRAY != json_typeof (denom_keys_array));
key_data->denom_keys = GNUNET_new_array (key_data->num_denom_keys,
struct TALER_EXCHANGE_DenomPublicKey);
index = 0;
json_array_foreach (denom_keys_array, index, denom_key_obj) {
struct TALER_EXCHANGE_DenomPublicKey dk;
bool found = false;
EXITIF (GNUNET_SYSERR ==
parse_json_denomkey (&dk,
denom_key_obj,
&key_data->master_pub,
hash_context));
for (unsigned int j=0;j<key_data->num_denom_keys;j++)
{
if (0 == memcmp (&dk,
&key_data->denom_keys[j],
sizeof (dk)))
{
found = true;
break;
}
}
if (found)
{
/* 0:0:0 did not support /keys cherry picking */
GNUNET_break_op (0 == current);
continue;
}
if (key_data->denom_keys_size == key_data->num_denom_keys)
GNUNET_array_grow (key_data->denom_keys,
key_data->denom_keys_size,
key_data->denom_keys_size * 2 + 2);
key_data->denom_keys[key_data->num_denom_keys++] = dk;
}
}
/* parse the auditor information */
{
json_t *auditors_array;
json_t *auditor_info;
unsigned int len;
unsigned int index;
EXITIF (NULL == (auditors_array =
json_object_get (resp_obj, "auditors")));
EXITIF (JSON_ARRAY != json_typeof (auditors_array));
len = json_array_size (auditors_array);
if (0 != len)
{
key_data->auditors = GNUNET_new_array (len,
struct TALER_EXCHANGE_AuditorInformation);
index = 0;
json_array_foreach (auditors_array, index, auditor_info) {
EXITIF (GNUNET_SYSERR ==
parse_json_auditor (&key_data->auditors[index],
auditor_info,
key_data));
}
key_data->num_auditors = len;
}
}
key_data->last_issue_date = list_issue_date;
/* Validate signature... */
ks.purpose.size = htonl (sizeof (ks));
ks.purpose.purpose = htonl (TALER_SIGNATURE_EXCHANGE_KEY_SET);
ks.list_issue_date = GNUNET_TIME_absolute_hton (list_issue_date);
GNUNET_CRYPTO_hash_context_finish (hash_context,
&ks.hc);
hash_context = NULL;
EXITIF (GNUNET_OK !=
TALER_EXCHANGE_test_signing_key (key_data,
&pub));
EXITIF (GNUNET_OK !=
GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_EXCHANGE_KEY_SET,
&ks.purpose,
&sig.eddsa_signature,
&pub.eddsa_pub));
return GNUNET_OK;
EXITIF_exit:
if (NULL != hash_context)
GNUNET_CRYPTO_hash_context_abort (hash_context);
return GNUNET_SYSERR;
}
/**
* Free key data object.
*
* @param key_data data to free (pointer itself excluded)
*/
static void
free_key_data (struct TALER_EXCHANGE_Keys *key_data)
{
GNUNET_array_grow (key_data->sign_keys,
key_data->sign_keys_size,
0);
for (unsigned int i=0;i<key_data->num_denom_keys;i++)
GNUNET_CRYPTO_rsa_public_key_free (key_data->denom_keys[i].key.rsa_public_key);
GNUNET_array_grow (key_data->denom_keys,
key_data->denom_keys_size,
0);
for (unsigned int i=0;i<key_data->num_auditors;i++)
{
GNUNET_array_grow (key_data->auditors[i].denom_keys,
key_data->auditors[i].num_denom_keys,
0);
GNUNET_free (key_data->auditors[i].auditor_url);
}
GNUNET_array_grow (key_data->auditors,
key_data->num_auditors,
0);
GNUNET_free_non_null (key_data->version);
key_data->version = NULL;
}
/**
* Initiate download of /keys from the exchange.
*
* @param exchange where to download /keys from
*/
static void
request_keys (struct TALER_EXCHANGE_Handle *exchange);
/**
* Check if our current response for /keys is valid, and if
* not trigger download.
*
* @param exchange exchange to check keys for
* @return until when the response is current, 0 if we are re-downloading
*/
struct GNUNET_TIME_Absolute
TALER_EXCHANGE_check_keys_current (struct TALER_EXCHANGE_Handle *exchange)
{
if (NULL != exchange->kr)
return GNUNET_TIME_UNIT_ZERO_ABS;
if (0 < GNUNET_TIME_absolute_get_remaining (exchange->key_data_expiration).rel_value_us)
return exchange->key_data_expiration;
request_keys (exchange);
return GNUNET_TIME_UNIT_ZERO_ABS;
}
/**
* Callback used when downloading the reply to a /keys request
* is complete.
*
* @param cls the `struct KeysRequest`
* @param response_code HTTP response code, 0 on error
* @param resp_obj parsed JSON result, NULL on error
*/
static void
keys_completed_cb (void *cls,
long response_code,
const json_t *resp_obj)
{
struct KeysRequest *kr = cls;
struct TALER_EXCHANGE_Handle *exchange = kr->exchange;
struct TALER_EXCHANGE_Keys kd;
struct TALER_EXCHANGE_Keys kd_old;
enum TALER_EXCHANGE_VersionCompatibility vc;
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
"Received keys from URL `%s' with status %ld.\n",
kr->url,
response_code);
kd_old = exchange->key_data;
vc = TALER_EXCHANGE_VC_PROTOCOL_ERROR;
switch (response_code)
{
case 0:
break;
case MHD_HTTP_OK:
if (NULL == resp_obj)
{
response_code = 0;
break;
}
if (GNUNET_OK !=
decode_keys_json (resp_obj,
&kd,
&vc))
{
response_code = 0;
break;
}
exchange->key_data = kd;
json_decref (exchange->key_data_raw);
exchange->key_data_raw = json_deep_copy (resp_obj);
break;
default:
GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
"Unexpected response code %u\n",
(unsigned int) response_code);
break;
}
if (MHD_HTTP_OK != response_code)
{
exchange->kr = NULL;
free_keys_request (kr);
exchange->state = MHS_FAILED;
/* notify application that we failed */
exchange->cert_cb (exchange->cert_cb_cls,
NULL,
vc);
if (NULL != exchange->key_data_raw)
{
json_decref (exchange->key_data_raw);
exchange->key_data_raw = NULL;
}
free_key_data (&kd_old);
return;
}
exchange->kr = NULL;
exchange->key_data_expiration = kr->expire;
free_keys_request (kr);
exchange->state = MHS_CERT;
/* notify application about the key information */
exchange->cert_cb (exchange->cert_cb_cls,
&exchange->key_data,
vc);
free_key_data (&kd_old);
}
/* ********************* library internal API ********* */
/**
* Get the context of a exchange.
*
* @param h the exchange handle to query
* @return ctx context to execute jobs in
*/
struct GNUNET_CURL_Context *
MAH_handle_to_context (struct TALER_EXCHANGE_Handle *h)
{
return h->ctx;
}
/**
* Check if the handle is ready to process requests.
*
* @param h the exchange handle to query
* @return #GNUNET_YES if we are ready, #GNUNET_NO if not
*/
int
MAH_handle_is_ready (struct TALER_EXCHANGE_Handle *h)
{
return (MHS_CERT == h->state) ? GNUNET_YES : GNUNET_NO;
}
/**
* Obtain the URL to use for an API request.
*
* @param h handle for the exchange
* @param path Taler API path (i.e. "/reserve/withdraw")
* @return the full URI to use with cURL
*/
char *
MAH_path_to_url (struct TALER_EXCHANGE_Handle *h,
const char *path)
{
return MAH_path_to_url2 (h->url,
path);
}
/**
* Obtain the URL to use for an API request.
*
* @param base_url base URL of the exchange (i.e. "http://exchange/")
* @param path Taler API path (i.e. "/reserve/withdraw")
* @return the full URI to use with cURL
*/
char *
MAH_path_to_url2 (const char *base_url,
const char *path)
{
char *url;
if ( ('/' == path[0]) &&
(0 < strlen (base_url)) &&
('/' == base_url[strlen (base_url) - 1]) )
path++; /* avoid generating URL with "//" from concat */
GNUNET_asprintf (&url,
"%s%s",
base_url,
path);
return url;
}
/**
* Parse HTTP timestamp.
*
* @param date header to parse header
* @param at where to write the result
* @return #GNUNET_OK on success
*/
static int
parse_date_string (const char *date,
struct GNUNET_TIME_Absolute *at)
{
static const char *const days[] =
{ "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat" };
static const char *const mons[] =
{ "Jan", "Feb", "Mar", "Apr", "May", "Jun",
"Jul", "Aug", "Sep", "Oct", "Nov", "Dec" };
struct tm now;
time_t t;
char day[4];
char mon[4];
unsigned int i;
unsigned int mday;
unsigned int year;
unsigned int h;
unsigned int m;
unsigned int s;
if (7 != sscanf (date,
"%3s, %02u %3s %04u %02u:%02u:%02u GMT",
day,
&mday,
mon,
&year,
&h,
&m,
&s))
return GNUNET_SYSERR;
memset (&now, 0, sizeof (now));
now.tm_year = year - 1900;
now.tm_mday = mday;
now.tm_hour = h;
now.tm_min = m;
now.tm_sec = s;
now.tm_wday = 7;
for (i=0;i<7;i++)
if (0 == strcasecmp (days[i], day))
now.tm_wday = i;
now.tm_mon = 12;
for (i=0;i<12;i++)
if (0 == strcasecmp (mons[i], mon))
now.tm_mon = i;
if ( (7 == now.tm_wday) ||
(12 == now.tm_mon) )
return GNUNET_SYSERR;
t = mktime (&now);
at->abs_value_us = 1000LL * 1000LL * t;
return GNUNET_OK;
}
/**
* Function called for each header in the HTTP /keys response.
* Finds the "Expire:" header and parses it, storing the result
* in the "expire" field fo the keys request.
*
* @param buffer header data received
* @param size size of an item in @a buffer
* @param nitems number of items in @a buffer
* @param userdata the `struct KeysRequest`
* @return `size * nitems` on success (everything else aborts)
*/
static size_t
header_cb (char *buffer,
size_t size,
size_t nitems,
void *userdata)
{
struct KeysRequest *kr = userdata;
size_t total = size * nitems;
char *val;
if (total < strlen (MHD_HTTP_HEADER_EXPIRES ": "))
return total;
if (0 != strncasecmp (MHD_HTTP_HEADER_EXPIRES ": ",
buffer,
strlen (MHD_HTTP_HEADER_EXPIRES ": ")))
return total;
val = GNUNET_strndup (&buffer[strlen (MHD_HTTP_HEADER_EXPIRES ": ")],
total - strlen (MHD_HTTP_HEADER_EXPIRES ": "));
if (GNUNET_OK !=
parse_date_string (val,
&kr->expire))
{
GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
"Failed to parse %s-header `%s'\n",
MHD_HTTP_HEADER_EXPIRES,
val);
}
GNUNET_free (val);
return total;
}
/* ********************* public API ******************* */
/**
* Initialise a connection to the exchange. Will connect to the
* exchange and obtain information about the exchange's master public
* key and the exchange's auditor. The respective information will
* be passed to the @a cert_cb once available, and all future
* interactions with the exchange will be checked to be signed
* (where appropriate) by the respective master key.
*
* @param ctx the context
* @param url HTTP base URL for the exchange
* @param cert_cb function to call with the exchange's certification information
* @param cert_cb_cls closure for @a cert_cb
* @param ... list of additional arguments, terminated by #TALER_EXCHANGE_OPTION_END.
* @return the exchange handle; NULL upon error
*/
struct TALER_EXCHANGE_Handle *
TALER_EXCHANGE_connect (struct GNUNET_CURL_Context *ctx,
const char *url,
TALER_EXCHANGE_CertificationCallback cert_cb,
void *cert_cb_cls,
...)
{
struct TALER_EXCHANGE_Handle *exchange;
exchange = GNUNET_new (struct TALER_EXCHANGE_Handle);
exchange->ctx = ctx;
exchange->url = GNUNET_strdup (url);
exchange->cert_cb = cert_cb;
exchange->cert_cb_cls = cert_cb_cls;
request_keys (exchange);
return exchange;
}
/**
* Initiate download of /keys from the exchange.
*
* @param exchange where to download /keys from
*/
static void
request_keys (struct TALER_EXCHANGE_Handle *exchange)
{
struct KeysRequest *kr;
CURL *eh;
GNUNET_assert (NULL == exchange->kr);
kr = GNUNET_new (struct KeysRequest);
kr->exchange = exchange;
if (GNUNET_YES == MAH_handle_is_ready (exchange))
{
char *arg;
GNUNET_asprintf (&arg,
"/keys?last_issue_date=%llu",
(unsigned long long) exchange->key_data.last_issue_date.abs_value_us);
kr->url = MAH_path_to_url (exchange,
arg);
GNUNET_free (arg);
}
else
{
kr->url = MAH_path_to_url (exchange,
"/keys");
}
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
"Requesting keys with URL `%s'.\n",
kr->url);
eh = curl_easy_init ();
GNUNET_assert (CURLE_OK ==
curl_easy_setopt (eh,
CURLOPT_VERBOSE,
0));
GNUNET_assert (CURLE_OK ==
curl_easy_setopt (eh,
CURLOPT_TIMEOUT,
(long) 300));
GNUNET_assert (CURLE_OK ==
curl_easy_setopt (eh,
CURLOPT_HEADERFUNCTION,
&header_cb));
GNUNET_assert (CURLE_OK ==
curl_easy_setopt (eh,
CURLOPT_HEADERDATA,
kr));
GNUNET_assert (CURLE_OK ==
curl_easy_setopt (eh,
CURLOPT_URL,
kr->url));
kr->job = GNUNET_CURL_job_add (exchange->ctx,
eh,
GNUNET_NO,
&keys_completed_cb,
kr);
exchange->kr = kr;
}
/**
* Disconnect from the exchange
*
* @param exchange the exchange handle
*/
void
TALER_EXCHANGE_disconnect (struct TALER_EXCHANGE_Handle *exchange)
{
if (NULL != exchange->kr)
{
GNUNET_CURL_job_cancel (exchange->kr->job);
free_keys_request (exchange->kr);
exchange->kr = NULL;
}
free_key_data (&exchange->key_data);
if (NULL != exchange->key_data_raw)
{
json_decref (exchange->key_data_raw);
exchange->key_data_raw = NULL;
}
GNUNET_free (exchange->url);
GNUNET_free (exchange);
}
/**
* Test if the given @a pub is a the current signing key from the exchange
* according to @a keys.
*
* @param keys the exchange's key set
* @param pub claimed current online signing key for the exchange
* @return #GNUNET_OK if @a pub is (according to /keys) a current signing key
*/
int
TALER_EXCHANGE_test_signing_key (const struct TALER_EXCHANGE_Keys *keys,
const struct TALER_ExchangePublicKeyP *pub)
{
struct GNUNET_TIME_Absolute now;
unsigned int i;
/* we will check using a tolerance of 1h for the time */
now = GNUNET_TIME_absolute_get ();
for (i=0;i<keys->num_sign_keys;i++)
if ( (keys->sign_keys[i].valid_from.abs_value_us <= now.abs_value_us + 60 * 60 * 1000LL * 1000LL) &&
(keys->sign_keys[i].valid_until.abs_value_us > now.abs_value_us - 60 * 60 * 1000LL * 1000LL) &&
(0 == memcmp (pub,
&keys->sign_keys[i].key,
sizeof (struct TALER_ExchangePublicKeyP))) )
return GNUNET_OK;
return GNUNET_SYSERR;
}
/**
* Obtain the denomination key details from the exchange.
*
* @param keys the exchange's key set
* @param pk public key of the denomination to lookup
* @return details about the given denomination key, NULL if the key is
* not found
*/
const struct TALER_EXCHANGE_DenomPublicKey *
TALER_EXCHANGE_get_denomination_key (const struct TALER_EXCHANGE_Keys *keys,
const struct TALER_DenominationPublicKey *pk)
{
unsigned int i;
for (i=0;i<keys->num_denom_keys;i++)
if (0 == GNUNET_CRYPTO_rsa_public_key_cmp (pk->rsa_public_key,
keys->denom_keys[i].key.rsa_public_key))
return &keys->denom_keys[i];
return NULL;
}
/**
* Obtain the denomination key details from the exchange.
*
* @param keys the exchange's key set
* @param hc hash of the public key of the denomination to lookup
* @return details about the given denomination key
*/
const struct TALER_EXCHANGE_DenomPublicKey *
TALER_EXCHANGE_get_denomination_key_by_hash (const struct TALER_EXCHANGE_Keys *keys,
const struct GNUNET_HashCode *hc)
{
unsigned int i;
for (i=0;i<keys->num_denom_keys;i++)
if (0 == memcmp (hc,
&keys->denom_keys[i].h_key,
sizeof (struct GNUNET_HashCode)))
return &keys->denom_keys[i];
return NULL;
}
/**
* Obtain the keys from the exchange.
*
* @param exchange the exchange handle
* @return the exchange's key set
*/
const struct TALER_EXCHANGE_Keys *
TALER_EXCHANGE_get_keys (struct TALER_EXCHANGE_Handle *exchange)
{
(void) TALER_EXCHANGE_check_keys_current (exchange);
return &exchange->key_data;
}
/**
* Obtain the keys from the exchange in the
* raw JSON format
*
* @param exchange the exchange handle
* @return the exchange's keys in raw JSON
*/
json_t *
TALER_EXCHANGE_get_keys_raw (struct TALER_EXCHANGE_Handle *exchange)
{
(void) TALER_EXCHANGE_check_keys_current (exchange);
return json_deep_copy (exchange->key_data_raw);
}
/* end of exchange_api_handle.c */
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