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#include "platform.h"
#include <jansson.h>
#include <taler/taler_signatures.h>
#include <gnunet/gnunet_util_lib.h>
#include "merchant.h"
#include "merchant_db.h"
#include "taler_merchant_contract_lib.h"
/* TODO: make this file a library, and programmatically call the following
* functions */
/**
* Macro to round microseconds to seconds in GNUNET_TIME_* structs.
*/
#define ROUND_TO_SECS(name,us_field) name.us_field -= name.us_field % (1000 * 1000)
/**
* Shorthand for exit jumps.
*/
#define EXITIF(cond) \
do { \
if (cond) { GNUNET_break (0); goto EXITIF_exit; } \
} while (0)
/**
* Generate the hash containing the information (= a nounce + merchant's IBAN) to
* redeem money from mint in a subsequent /deposit operation
* @param nounce the nounce
* @param wire the merchant's wire details
* @return the hash to be included in the contract's blob
*
*/
static struct GNUNET_HashCode
hash_wireformat (uint64_t nounce, const struct MERCHANT_WIREFORMAT_Sepa *wire)
{
struct GNUNET_HashContext *hc;
struct GNUNET_HashCode hash;
hc = GNUNET_CRYPTO_hash_context_start ();
GNUNET_CRYPTO_hash_context_read (hc, wire->iban, strlen (wire->iban));
GNUNET_CRYPTO_hash_context_read (hc, wire->name, strlen (wire->name));
GNUNET_CRYPTO_hash_context_read (hc, wire->bic, strlen (wire->bic));
nounce = GNUNET_htonll (nounce);
GNUNET_CRYPTO_hash_context_read (hc, &nounce, sizeof (nounce));
GNUNET_CRYPTO_hash_context_finish (hc, &hash);
return hash;
}
/**
* Take from the frontend the (partly) generated contract and fill
* the missing values in it; for example, the SEPA-aware values.
* Moreover, it stores the contract in the DB and does the signature of it.
* @param contract parsed contract, originated by the frontend
* @param db_conn the handle to the local DB
* @param kpriv merchant's private key
* @param wire merchant's bank's details
* @param sig where to store the signature
* @return pointer to the complete JSON; NULL upon errors
*/
/* TODO: this handles a simplified version (for debugging purposes)
of the contract. To expand to the full fledged version */
json_t *
MERCHANT_handle_contract (json_t *contract,
PGconn *db_conn,
struct GNUNET_CRYPTO_EddsaPrivateKey *kpriv,
const struct MERCHANT_WIREFORMAT_Sepa *wire,
struct GNUNET_CRYPTO_EddsaSignature *sig)
{
json_t *root;
json_t *j_timestamp;
json_t *jh_wire;
json_t *j_amount;
json_int_t j_trans_id;
uint64_t nounce;
uint64_t product_id;
char *a;
char *h_wire_enc;
char *str;
struct GNUNET_HashCode h_wire;
struct GNUNET_TIME_Absolute timestamp;
struct TALER_Amount amount;
struct TALER_AmountNBO amount_nbo;
struct ContractNBO contract_nbo;
nounce = GNUNET_CRYPTO_random_u64 (GNUNET_CRYPTO_QUALITY_NONCE, UINT64_MAX);
// timing mgmt
timestamp = GNUNET_TIME_absolute_add (GNUNET_TIME_absolute_get (),
GNUNET_TIME_UNIT_DAYS);
ROUND_TO_SECS (timestamp, abs_value_us);
j_timestamp = TALER_json_from_abs (timestamp);
// wireformat mgmt
h_wire = hash_wireformat (nounce, wire);
h_wire_enc = GNUNET_STRINGS_data_to_string_alloc (&h_wire,
sizeof (struct GNUNET_HashCode));
jh_wire = json_string (h_wire_enc);
str = json_dumps (contract, JSON_INDENT(2) | JSON_PRESERVE_ORDER);
json_unpack (contract, "{s:o, s:I}",
"amount", &j_amount,
"trans_id", &j_trans_id);
/* needed for DB stuff */
TALER_json_to_amount (j_amount, &amount);
/* temporary way of getting this value. To be adapted to the expanded contract
format. See 'TODO' above. */
product_id = GNUNET_CRYPTO_random_u64 (GNUNET_CRYPTO_QUALITY_NONCE, UINT64_MAX);
/* adding the generated values in this JSON */
root = json_pack ("{s:o, s:I, s:s, s:o}",
"amount", j_amount,
"trans_id", j_trans_id,
"h_wire", jh_wire,
"timestamp", j_timestamp);
a = json_dumps (root, JSON_COMPACT | JSON_PRESERVE_ORDER);
// DB mgmt
if (GNUNET_SYSERR == MERCHANT_DB_contract_create (db_conn,
×tamp,
&amount,
(uint64_t) j_trans_id, // safe?
a,
nounce,
product_id));
contract_nbo.h_wire = h_wire;
TALER_amount_hton (&amount_nbo, &amount);
contract_nbo.amount = amount_nbo;
contract_nbo.t = GNUNET_TIME_absolute_hton (timestamp);
contract_nbo.m = GNUNET_htonll ((uint64_t) j_trans_id); // safe?
GNUNET_CRYPTO_hash (a, strlen (a) + 1, &contract_nbo.h_contract_details);
free (a);
contract_nbo.purpose.purpose = htonl (TALER_SIGNATURE_MERCHANT_CONTRACT);
contract_nbo.purpose.size = htonl (sizeof (struct ContractNBO));
GNUNET_CRYPTO_eddsa_sign (kpriv, &contract_nbo.purpose, sig);
return root;
}
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