exchange

bank_api_transfer.c (10457B)

---

 /*
   This file is part of TALER
   Copyright (C) 2015--2023, 2026 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 bank-lib/bank_api_transfer.c
  * @brief Implementation of the /transfer/ requests of the bank's HTTP API
  * @author Christian Grothoff
  */
 #include "bank_api_common.h"
 #include <microhttpd.h> /* just for HTTP status codes */
 #include "taler/taler_signatures.h"
 #include "taler/taler_curl_lib.h"
 #include "taler/taler_bank_service.h"
 
 
 GNUNET_NETWORK_STRUCT_BEGIN
 
 /**
  * Data structure serialized in the prepare stage.
  */
 struct WirePackP
 {
   /**
    * Random unique identifier for the request.
    */
   struct GNUNET_HashCode request_uid;
 
   /**
    * Amount to be transferred.
    */
   struct TALER_AmountNBO amount;
 
   /**
    * Wire transfer identifier to use.
    */
   struct TALER_WireTransferIdentifierRawP wtid;
 
   /**
    * Length of the payto:// URL of the target account,
    * including 0-terminator, in network byte order.
    */
   uint32_t account_len GNUNET_PACKED;
 
   /**
    * Length of the exchange's base URL,
    * including 0-terminator, in network byte order.
    */
   uint32_t exchange_url_len GNUNET_PACKED;
 
 };
 
 GNUNET_NETWORK_STRUCT_END
 
 
 void
 TALER_BANK_prepare_transfer (
   const struct TALER_FullPayto destination_account_payto_uri,
   const struct TALER_Amount *amount,
   const char *exchange_base_url,
   const struct TALER_WireTransferIdentifierRawP *wtid,
   const char *extra_wire_transfer_subject,
   void **buf,
   size_t *buf_size)
 {
   const char *payto = destination_account_payto_uri.full_payto;
   struct WirePackP *wp;
   size_t d_len = strlen (payto) + 1;
   size_t u_len = strlen (exchange_base_url) + 1;
   size_t x_len = (NULL == extra_wire_transfer_subject)
     ? 0
     : strlen (extra_wire_transfer_subject) + 1;
   char *end;
 
   if ( (d_len >= (size_t) GNUNET_MAX_MALLOC_CHECKED) ||
        (u_len >= (size_t) GNUNET_MAX_MALLOC_CHECKED) ||
        (x_len >= (size_t) GNUNET_MAX_MALLOC_CHECKED) ||
        (d_len + u_len + x_len + sizeof (*wp) >= GNUNET_MAX_MALLOC_CHECKED) )
   {
     GNUNET_break (0); /* that's some long URL... */
     *buf = NULL;
     *buf_size = 0;
     return;
   }
   *buf_size = sizeof (*wp) + d_len + u_len + x_len;
   wp = GNUNET_malloc (*buf_size);
   GNUNET_CRYPTO_hash_create_random (GNUNET_CRYPTO_QUALITY_NONCE,
                                     &wp->request_uid);
   TALER_amount_hton (&wp->amount,
                      amount);
   wp->wtid = *wtid;
   wp->account_len = htonl ((uint32_t) d_len);
   wp->exchange_url_len = htonl ((uint32_t) u_len);
   end = (char *) &wp[1];
   GNUNET_memcpy (end,
                  payto,
                  d_len);
   GNUNET_memcpy (end + d_len,
                  exchange_base_url,
                  u_len);
   GNUNET_memcpy (end + d_len + u_len,
                  extra_wire_transfer_subject,
                  x_len);
   *buf = (char *) wp;
 }
 
 
 /**
  * @brief Handle for an active wire transfer.
  */
 struct TALER_BANK_TransferHandle
 {
 
   /**
    * The url for this request.
    */
   char *request_url;
 
   /**
    * POST context.
    */
   struct TALER_CURL_PostContext post_ctx;
 
   /**
    * Handle for the request.
    */
   struct GNUNET_CURL_Job *job;
 
   /**
    * Function to call with the result.
    */
   TALER_BANK_TransferCallback cb;
 
   /**
    * Closure for @a cb.
    */
   void *cb_cls;
 
 };
 
 
 /**
  * Function called when we're done processing the
  * HTTP /transfer request.
  *
  * @param cls the `struct TALER_BANK_TransferHandle`
  * @param response_code HTTP response code, 0 on error
  * @param response parsed JSON result, NULL on error
  */
 static void
 handle_transfer_finished (void *cls,
                           long response_code,
                           const void *response)
 {
   struct TALER_BANK_TransferHandle *th = cls;
   const json_t *j = response;
   struct TALER_BANK_TransferResponse tr = {
     .http_status = response_code,
     .response = j
   };
 
   th->job = NULL;
   switch (response_code)
   {
   case 0:
     tr.ec = TALER_EC_GENERIC_INVALID_RESPONSE;
     break;
   case MHD_HTTP_OK:
     {
       struct GNUNET_JSON_Specification spec[] = {
         GNUNET_JSON_spec_uint64 ("row_id",
                                  &tr.details.ok.row_id),
         GNUNET_JSON_spec_timestamp ("timestamp",
                                     &tr.details.ok.timestamp),
         GNUNET_JSON_spec_end ()
       };
 
       if (GNUNET_OK !=
           GNUNET_JSON_parse (j,
                              spec,
                              NULL, NULL))
       {
         GNUNET_break_op (0);
         tr.http_status = 0;
         tr.ec = TALER_EC_GENERIC_INVALID_RESPONSE;
         break;
       }
     }
     break;
   case MHD_HTTP_BAD_REQUEST:
     /* This should never happen, either us or the bank is buggy
        (or API version conflict); just pass JSON reply to the application */
     GNUNET_break_op (0);
     tr.ec = TALER_JSON_get_error_code (j);
     break;
   case MHD_HTTP_UNAUTHORIZED:
     /* Nothing really to verify, bank says our credentials are
        invalid. We should pass the JSON reply to the application. */
     tr.ec = TALER_JSON_get_error_code (j);
     break;
   case MHD_HTTP_NOT_FOUND:
     /* Nothing really to verify, endpoint wrong -- could be user unknown */
     tr.ec = TALER_JSON_get_error_code (j);
     break;
   case MHD_HTTP_CONFLICT:
     /* Nothing really to verify. Server says we used the same transfer request
        UID before, but with different details.  Should not happen if the user
        properly used #TALER_BANK_prepare_transfer() and our PRNG is not
        broken... */
     tr.ec = TALER_JSON_get_error_code (j);
     break;
   case MHD_HTTP_INTERNAL_SERVER_ERROR:
     /* Server had an internal issue; we should retry, but this API
        leaves this to the application */
     tr.ec = TALER_JSON_get_error_code (j);
     break;
   default:
     /* unexpected response code */
     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                 "Unexpected response code %u\n",
                 (unsigned int) response_code);
     GNUNET_break (0);
     tr.ec = TALER_JSON_get_error_code (j);
     break;
   }
   th->cb (th->cb_cls,
           &tr);
   TALER_BANK_transfer_cancel (th);
 }
 
 
 struct TALER_BANK_TransferHandle *
 TALER_BANK_transfer (
   struct GNUNET_CURL_Context *ctx,
   const struct TALER_BANK_AuthenticationData *auth,
   const void *buf,
   size_t buf_size,
   TALER_BANK_TransferCallback cc,
   void *cc_cls)
 {
   struct TALER_BANK_TransferHandle *th;
   json_t *transfer_obj;
   CURL *eh;
   const struct WirePackP *wp = buf;
   uint32_t d_len;
   uint32_t u_len;
   uint32_t x_len;
   const char *destination_account_uri;
   const char *exchange_base_url;
   const char *extra_metadata;
   struct TALER_Amount amount;
 
   if (sizeof (*wp) > buf_size)
   {
     GNUNET_break (0);
     return NULL;
   }
   d_len = ntohl (wp->account_len);
   u_len = ntohl (wp->exchange_url_len);
   if ( (sizeof (*wp) + d_len + u_len > buf_size) ||
        (d_len > buf_size) ||
        (u_len > buf_size) ||
        (d_len + u_len > buf_size) )
   {
     GNUNET_break (0);
     return NULL;
   }
   x_len = buf_size - (sizeof (*wp) + d_len + u_len);
   destination_account_uri = (const char *) &wp[1];
   exchange_base_url = destination_account_uri + d_len;
   if ( ('\0' != destination_account_uri[d_len - 1]) ||
        ('\0' != exchange_base_url[u_len - 1]) )
   {
     GNUNET_break (0);
     return NULL;
   }
   if (0 != x_len)
   {
     extra_metadata = destination_account_uri + d_len + u_len;
     if ('\0' != extra_metadata[x_len - 1])
     {
       GNUNET_break (0);
       return NULL;
     }
   }
   else
   {
     extra_metadata = NULL;
   }
 
   if (NULL == auth->wire_gateway_url)
   {
     GNUNET_break (0);
     return NULL;
   }
   TALER_amount_ntoh (&amount,
                      &wp->amount);
   th = GNUNET_new (struct TALER_BANK_TransferHandle);
   th->cb = cc;
   th->cb_cls = cc_cls;
   th->request_url = TALER_url_join (auth->wire_gateway_url,
                                     "transfer",
                                     NULL);
   if (NULL == th->request_url)
   {
     GNUNET_free (th);
     GNUNET_break (0);
     return NULL;
   }
   transfer_obj = GNUNET_JSON_PACK (
     GNUNET_JSON_pack_data_auto ("request_uid",
                                 &wp->request_uid),
     TALER_JSON_pack_amount ("amount",
                             &amount),
     GNUNET_JSON_pack_string ("exchange_base_url",
                              exchange_base_url),
     GNUNET_JSON_pack_allow_null (
       GNUNET_JSON_pack_string ("metadata",
                                extra_metadata)),
     GNUNET_JSON_pack_data_auto ("wtid",
                                 &wp->wtid),
     GNUNET_JSON_pack_string ("credit_account",
                              destination_account_uri));
   if (NULL == transfer_obj)
   {
     GNUNET_break (0);
     return NULL;
   }
   eh = curl_easy_init ();
   if ( (NULL == eh) ||
        (GNUNET_OK !=
         TALER_BANK_setup_auth_ (eh,
                                 auth)) ||
        (CURLE_OK !=
         curl_easy_setopt (eh,
                           CURLOPT_URL,
                           th->request_url)) ||
        (GNUNET_OK !=
         TALER_curl_easy_post (&th->post_ctx,
                               eh,
                               transfer_obj)) )
   {
     GNUNET_break (0);
     TALER_BANK_transfer_cancel (th);
     if (NULL != eh)
       curl_easy_cleanup (eh);
     json_decref (transfer_obj);
     return NULL;
   }
   json_decref (transfer_obj);
   th->job = GNUNET_CURL_job_add2 (ctx,
                                   eh,
                                   th->post_ctx.headers,
                                   &handle_transfer_finished,
                                   th);
   return th;
 }
 
 
 void
 TALER_BANK_transfer_cancel (struct TALER_BANK_TransferHandle *th)
 {
   if (NULL != th->job)
   {
     GNUNET_CURL_job_cancel (th->job);
     th->job = NULL;
   }
   TALER_curl_easy_post_finished (&th->post_ctx);
   GNUNET_free (th->request_url);
   GNUNET_free (th);
 }
 
 
 /* end of bank_api_transfer.c */