aboutsummaryrefslogtreecommitdiff
path: root/src/wire/plugin_wire_test.c
blob: 11feaea7efb3f8ecbfbab53ca792205e57946b5e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
/*
  This file is part of TALER
  Copyright (C) 2017 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 plugin_wire_test.c
 * @brief plugin for the "test" wire method
 * @author Christian Grothoff
 */
#include "platform.h"
#include "taler_wire_plugin.h"
#include "taler_bank_service.h"
#include "taler_signatures.h"
#include <gnunet/gnunet_curl_lib.h>

/* only for HTTP status codes */
#include <microhttpd.h>

/**
 * Type of the "cls" argument given to each of the functions in
 * our API.
 */
struct TestClosure
{

  /**
   * Which currency do we support?
   */
  char *currency;

  /**
   * URL of our bank.
   */
  char *bank_url;

  /**
   * Authentication information.
   */
  struct TALER_BANK_AuthenticationData auth;

  /**
   * Handle to the context for sending funds to the bank.
   */
  struct GNUNET_CURL_Context *ctx;

  /**
   * Scheduler context for running the @e ctx.
   */
  struct GNUNET_CURL_RescheduleContext *rc;

  /**
   * Number of the account that the exchange has at the bank for
   * transfers.
   */
  unsigned long long exchange_account_no;

};


/**
 * Handle returned by #test_prepare_wire_transfer.
 */
struct TALER_WIRE_PrepareHandle
{

  /**
   * Task we use for async execution.
   */
  struct GNUNET_SCHEDULER_Task *task;

  /**
   * Test closure we run in.
   */
  struct TestClosure *tc;

  /**
   * Wire data for the transfer.
   */
  json_t *wire;

  /**
   * Base URL to use for the exchange.
   */
  char *exchange_base_url;

  /**
   * Function to call with the serialized data.
   */
  TALER_WIRE_PrepareTransactionCallback ptc;

  /**
   * Closure for @e ptc.
   */
  void *ptc_cls;

  /**
   * Amount to transfer.
   */
  struct TALER_Amount amount;

  /**
   * Subject of the wire transfer.
   */
  struct TALER_WireTransferIdentifierRawP wtid;


};


/**
 * Handle returned by #test_execute_wire_transfer.
 */
struct TALER_WIRE_ExecuteHandle
{

  /**
   * Handle to the HTTP request to the bank.
   */
  struct TALER_BANK_AdminAddIncomingHandle *aaih;

  /**
   * Function to call with the result.
   */
  TALER_WIRE_ConfirmationCallback cc;

  /**
   * Closure for @e cc.
   */
  void *cc_cls;
};



/**
 * Round amount DOWN to the amount that can be transferred via the wire
 * method.  For example, Taler may support 0.000001 EUR as a unit of
 * payment, but SEPA only supports 0.01 EUR.  This function would
 * round 0.125 EUR to 0.12 EUR in this case.
 *
 * @param cls the @e cls of this struct with the plugin-specific state
 * @param[in,out] amount amount to round down
 * @return #GNUNET_OK on success, #GNUNET_NO if rounding was unnecessary,
 *         #GNUNET_SYSERR if the amount or currency was invalid
 */
static int
test_amount_round (void *cls,
                   struct TALER_Amount *amount)
{
  struct TestClosure *tc = cls;
  uint32_t delta;

  if (NULL == tc->currency)
  {
    GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR,
                               "taler",
                               "CURRENCY");
    return GNUNET_SYSERR; /* not configured with currency */
  }
  if (0 != strcasecmp (amount->currency,
                       tc->currency))
  {
    GNUNET_break (0);
    return GNUNET_SYSERR;
  }
  /* 'test' method supports 1/100 of the unit currency, i.e. 0.01 CUR */
  delta = amount->fraction % (TALER_AMOUNT_FRAC_BASE / 100);
  if (0 == delta)
    return GNUNET_NO;
  amount->fraction -= delta;
  return GNUNET_OK;
}


/**
 * Compute purpose for signing.
 *
 * @param account number of the account
 * @param bank_url URL of the bank
 * @param[out] wsd purpose to be signed
 */
static void
compute_purpose (uint64_t account,
                 const char *bank_url,
                 struct TALER_MasterWireDetailsPS *wsd)
{
  struct GNUNET_HashContext *hc;
  uint64_t n = GNUNET_htonll (account);

  wsd->purpose.size = htonl (sizeof (struct TALER_MasterWireDetailsPS));
  wsd->purpose.purpose = htonl (TALER_SIGNATURE_MASTER_TEST_DETAILS);
  hc = GNUNET_CRYPTO_hash_context_start ();
  GNUNET_CRYPTO_hash_context_read (hc,
				   "test",
				   strlen ("test") + 1);
  GNUNET_CRYPTO_hash_context_read (hc,
				   &n,
                                   sizeof (n));
  GNUNET_CRYPTO_hash_context_read (hc,
				   bank_url,
				   strlen (bank_url) + 1);
  GNUNET_CRYPTO_hash_context_finish (hc,
				     &wsd->h_sepa_details);
}


/**
 * Check if the given wire format JSON object is correctly formatted.
 * Right now, the only thing we require is a field
 * "account_number" which must contain a positive 53-bit integer.
 *
 * @param cls the @e cls of this struct with the plugin-specific state
 * @param wire the JSON wire format object
 * @param master_pub public key of the exchange to verify against
 * @param[out] emsg set to an error message, unless we return #TALER_EC_NONE;
 *             error message must be freed by the caller using GNUNET_free()
 * @return #TALER_EC_NONE if correctly formatted
 */
static enum TALER_ErrorCode
test_wire_validate (void *cls,
                    const json_t *wire,
                    const struct TALER_MasterPublicKeyP *master_pub,
                    char **emsg)
{
  struct TestClosure *tc = cls;
  json_error_t error;
  json_int_t account_no;
  const char *bank_url;
  const char *sig_s;
  struct TALER_MasterWireDetailsPS wsd;
  struct TALER_MasterSignatureP sig;

  *emsg = NULL;
  if (0 !=
      json_unpack_ex ((json_t *) wire,
		      &error,
		      0,
		      "{s:I, s:s}",
		      "account_number", &account_no,
                      "bank_url", &bank_url))
  {
    char *dump;

    dump = json_dumps (wire, 0);
    GNUNET_asprintf (emsg,
                     "JSON parsing failed at %s:%u: %s (%s): %s\n",
                     __FILE__, __LINE__,
                     error.text,
                     error.source,
                     dump);
    free (dump);
    return TALER_EC_DEPOSIT_INVALID_WIRE_FORMAT_JSON;
  }
  if ( (account_no < 0) ||
       (account_no > (1LL << 53)) )
  {
    GNUNET_asprintf (emsg,
                     "Account number %llu outside of permitted range\n",
                     account_no);
    return TALER_EC_DEPOSIT_INVALID_WIRE_FORMAT_ACCOUNT_NUMBER;
  }
  if ( (NULL != tc->bank_url) &&
       (0 != strcmp (bank_url,
                     tc->bank_url)) )
  {
    GNUNET_asprintf (emsg,
                     "Wire specifies bank URL `%s', but this exchange only supports `%s'\n",
                     bank_url,
                     tc->bank_url);
    return TALER_EC_DEPOSIT_INVALID_WIRE_FORMAT_BANK;
  }
  if (NULL == master_pub)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "Skipping signature check as master public key not given\n");
    return TALER_EC_NONE;
  }
  if (0 !=
      json_unpack_ex ((json_t *) wire,
		      &error,
		      0,
		      "{s:s}",
                      "sig", &sig_s))
  {
    GNUNET_asprintf (emsg,
                     "Signature check required, but signature is missing\n");
    return TALER_EC_DEPOSIT_INVALID_WIRE_FORMAT_SIGNATURE;
  }
  compute_purpose (account_no,
                   bank_url,
                   &wsd);
  if (GNUNET_OK !=
      GNUNET_STRINGS_string_to_data (sig_s,
                                     strlen (sig_s),
                                     &sig,
                                     sizeof (sig)))
  {
    GNUNET_break (0);
    return TALER_EC_DEPOSIT_INVALID_WIRE_FORMAT_SIGNATURE;
  }
  if (GNUNET_OK !=
      GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_MASTER_TEST_DETAILS,
                                  &wsd.purpose,
                                  &sig.eddsa_signature,
                                  &master_pub->eddsa_pub))
  {
    GNUNET_asprintf (emsg,
                     "Signature using public key `%s' invalid\n",
                     TALER_B2S (master_pub));
    return TALER_EC_DEPOSIT_INVALID_WIRE_FORMAT_SIGNATURE;
  }
  return TALER_EC_NONE;
}


/**
 * Obtain wire transfer details in the plugin-specific format
 * from the configuration.
 *
 * @param cls closure
 * @param cfg configuration with details about wire accounts
 * @param account_name which section in the configuration should we parse
 * @return NULL if @a cfg fails to have valid wire details for @a account_name
 */
static json_t *
test_get_wire_details (void *cls,
                       const struct GNUNET_CONFIGURATION_Handle *cfg,
                       const char *account_name)
{
  struct TestClosure *tc = cls;
  char *test_wire_file;
  json_error_t err;
  json_t *ret;
  char *emsg;

  /* Fetch reply */
  if (GNUNET_OK !=
      GNUNET_CONFIGURATION_get_value_filename (cfg,
                                               account_name,
                                               "TEST_RESPONSE_FILE",
                                               &test_wire_file))
  {
    GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR,
                               account_name,
                               "TEST_RESPONSE_FILE");
    return NULL;
  }
  ret = json_load_file (test_wire_file,
                        JSON_REJECT_DUPLICATES,
                        &err);
  if (NULL == ret)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Failed to parse JSON in %s: %s (%s:%u)\n",
                test_wire_file,
                err.text,
                err.source,
                err.line);
    GNUNET_free (test_wire_file);
    return NULL;
  }
  if (TALER_EC_NONE !=
      test_wire_validate (tc,
                          ret,
                          NULL,
                          &emsg))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Failed to validate TEST wire data in %s: %s\n",
                test_wire_file,
                emsg);
    GNUNET_free (emsg);
    GNUNET_free (test_wire_file);
    json_decref (ret);
    return NULL;
  }
  GNUNET_free (test_wire_file);
  return ret;
}


GNUNET_NETWORK_STRUCT_BEGIN
/**
 * Format we used for serialized transaction data.
 */
struct BufFormatP
{

  /**
   * The wire transfer identifier.
   */
  struct TALER_WireTransferIdentifierRawP wtid;

  /**
   * The amount.
   */
  struct TALER_AmountNBO amount;

  /* followed by serialized 'wire' JSON data (0-terminated) */

  /* followed by 0-terminated base URL */

};
GNUNET_NETWORK_STRUCT_END


/**
 * Abort preparation of a wire transfer. For example,
 * because we are shutting down.
 *
 * @param cls the @e cls of this struct with the plugin-specific state
 * @param pth preparation to cancel
 */
static void
test_prepare_wire_transfer_cancel (void *cls,
                                   struct TALER_WIRE_PrepareHandle *pth)
{
  if (NULL != pth->task)
    GNUNET_SCHEDULER_cancel (pth->task);
  json_decref (pth->wire);
  GNUNET_free (pth->exchange_base_url);
  GNUNET_free (pth);
}


/**
 * Prepare for exeuction of a wire transfer.  Calls the
 * callback with the serialized state.
 *
 * @param cls the `struct TALER_WIRE_PrepareHandle`
 */
static void
do_prepare (void *cls)
{
  struct TALER_WIRE_PrepareHandle *pth = cls;
  char *wire_enc;
  size_t len_w;
  size_t len_b;
  struct BufFormatP bf;

  pth->task = NULL;
  /* serialize the state into a 'buf' */
  wire_enc = json_dumps (pth->wire,
                         JSON_COMPACT | JSON_SORT_KEYS);
  if (NULL == wire_enc)
  {
    GNUNET_break (0);
    pth->ptc (pth->ptc_cls,
              NULL,
              0);
    test_prepare_wire_transfer_cancel (NULL,
                                       pth);
    return;
  }
  len_w = strlen (wire_enc) + 1;
  len_b = strlen (pth->exchange_base_url) + 1;
  bf.wtid = pth->wtid;
  TALER_amount_hton (&bf.amount,
                     &pth->amount);
  {
    char buf[sizeof (struct BufFormatP) + len_w + len_b];

    memcpy (buf,
            &bf,
            sizeof (struct BufFormatP));
    memcpy (&buf[sizeof (struct BufFormatP)],
            wire_enc,
            len_w);
    memcpy (&buf[sizeof (struct BufFormatP) + len_w],
            pth->exchange_base_url,
            len_b);

    /* finally give the state back */
    pth->ptc (pth->ptc_cls,
              buf,
              sizeof (buf));
  }
  free (wire_enc); /* not using GNUNET_free(),
                      as this one is allocated by libjansson */
  test_prepare_wire_transfer_cancel (NULL,
                                     pth);
}


/**
 * Prepare for exeuction of a wire transfer.  Note that we should call
 * @a ptc asynchronously (as that is what the API requires, because
 * some transfer methods need it).  So while we could immediately call
 * @a ptc, we first bundle up all the data and schedule a task to do
 * the work.
 *
 * @param cls the @e cls of this struct with the plugin-specific state
 * @param wire valid wire account information
 * @param amount amount to transfer, already rounded
 * @param exchange_base_url base URL of this exchange
 * @param wtid wire transfer identifier to use
 * @param ptc function to call with the prepared data to persist
 * @param ptc_cls closure for @a ptc
 * @return NULL on failure
 */
static struct TALER_WIRE_PrepareHandle *
test_prepare_wire_transfer (void *cls,
                            const json_t *wire,
                            const struct TALER_Amount *amount,
                            const char *exchange_base_url,
                            const struct TALER_WireTransferIdentifierRawP *wtid,
                            TALER_WIRE_PrepareTransactionCallback ptc,
                            void *ptc_cls)
{
  struct TestClosure *tc = cls;
  struct TALER_WIRE_PrepareHandle *pth;
  char *emsg;

  if (TALER_EC_NONE !=
      test_wire_validate (tc,
                          wire,
                          NULL,
                          &emsg))
  {
    GNUNET_break_op (0);
    GNUNET_free (emsg);
    return NULL;
  }
  pth = GNUNET_new (struct TALER_WIRE_PrepareHandle);
  pth->tc = tc;
  pth->wire = json_incref ((json_t *) wire);
  pth->exchange_base_url = GNUNET_strdup (exchange_base_url);
  pth->wtid = *wtid;
  pth->ptc = ptc;
  pth->ptc_cls = ptc_cls;
  pth->amount = *amount;
  pth->task = GNUNET_SCHEDULER_add_now (&do_prepare,
                                        pth);
  return pth;
}


/**
 * Called with the result of submitting information about an incoming
 * transaction to a bank.
 *
 * @param cls closure with the `struct TALER_WIRE_ExecuteHandle`
 * @param http_status HTTP response code, #MHD_HTTP_OK (200) for successful status request
 *                    0 if the bank's reply is bogus (fails to follow the protocol)
 * @param ec error code from the bank
 * @param serial_id unique ID of the wire transfer in the bank's records; UINT64_MAX on error
 * @param json detailed response from the HTTPD, or NULL if reply was not JSON
 */
static void
execute_cb (void *cls,
            unsigned int http_status,
            enum TALER_ErrorCode ec,
            uint64_t serial_id,
            const json_t *json)
{
  struct TALER_WIRE_ExecuteHandle *eh = cls;
  json_t *reason;
  const char *emsg;
  char *s;

  eh->aaih = NULL;
  emsg = NULL;
  if (NULL != json)
  {
    reason = json_object_get (json,
                              "reason");
    if (NULL != reason)
      emsg = json_string_value (reason);
  }
  if (NULL != emsg)
    GNUNET_asprintf (&s,
                     "%u/%u (%s)",
                     http_status,
                     (unsigned int) ec,
                     emsg);
  else
    GNUNET_asprintf (&s,
                     "%u/%u",
                     http_status,
                     (unsigned int) ec);
  eh->cc (eh->cc_cls,
          (MHD_HTTP_OK == http_status) ? GNUNET_OK : GNUNET_SYSERR,
          serial_id,
          (MHD_HTTP_OK == http_status) ? NULL : s);
  GNUNET_free (s);
  GNUNET_free (eh);
}


/**
 * Sign wire transfer details in the plugin-specific format.
 *
 * @param cls closure
 * @param in wire transfer details in JSON format
 * @param key private signing key to use
 * @param salt salt to add
 * @param[out] sig where to write the signature
 * @return #GNUNET_OK on success
 */
static int
test_sign_wire_details (void *cls,
                        const json_t *in,
                        const struct TALER_MasterPrivateKeyP *key,
                        const struct GNUNET_HashCode *salt,
                        struct TALER_MasterSignatureP *sig)
{
  struct TALER_MasterWireDetailsPS wsd;
  const char *bank_url;
  const char *type;
  json_int_t account;
  json_error_t err;

  if (0 !=
      json_unpack_ex ((json_t *) in,
                      &err,
                      0 /* flags */,
                      "{s:s, s:s, s:I}",
                      "type", &type,
                      "bank_url", &bank_url,
                      "account_number", &account))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                "Failed to unpack JSON: %s (at %u)\n",
                err.text,
                err.position);
    return GNUNET_SYSERR;
  }
  if (0 != strcmp (type,
                   "test"))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                "`type' must be `test' for test wire details\n");
    return GNUNET_SYSERR;
  }
  compute_purpose (account,
                   bank_url,
                   &wsd);
  GNUNET_CRYPTO_eddsa_sign (&key->eddsa_priv,
			    &wsd.purpose,
			    &sig->eddsa_signature);
  return GNUNET_OK;
}


/**
 * Execute a wire transfer.
 *
 * @param cls the @e cls of this struct with the plugin-specific state
 * @param buf buffer with the prepared execution details
 * @param buf_size number of bytes in @a buf
 * @param cc function to call upon success
 * @param cc_cls closure for @a cc
 * @return NULL on error
 */
static struct TALER_WIRE_ExecuteHandle *
test_execute_wire_transfer (void *cls,
                            const char *buf,
                            size_t buf_size,
                            TALER_WIRE_ConfirmationCallback cc,
                            void *cc_cls)
{
  struct TestClosure *tc = cls;
  struct TALER_WIRE_ExecuteHandle *eh;
  json_t *wire;
  json_error_t error;
  struct TALER_Amount amount;
  json_int_t account_no;
  struct BufFormatP bf;
  char *emsg;
  const char *json_s;
  const char *exchange_base_url;
  char *wire_s;

  if (NULL == tc->ctx)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Bank not initialized, cannot do transfers!\n");
    return NULL; /* not initialized with configuration, cannot do transfers */
  }
  if ( (buf_size <= sizeof (struct BufFormatP)) ||
       ('\0' != buf[buf_size - 1]) )
  {
    GNUNET_break (0);
    return NULL;
  }
  json_s = &buf[sizeof (struct BufFormatP)];
  exchange_base_url = &json_s[strlen (json_s) + 1];
  if (exchange_base_url > &buf[buf_size - 1])
  {
    GNUNET_break (0);
    return NULL;
  }
  memcpy (&bf,
          buf,
          sizeof (bf));
  TALER_amount_ntoh (&amount,
                     &bf.amount);
  wire = json_loads (json_s,
                     JSON_REJECT_DUPLICATES,
                     NULL);
  if (NULL == wire)
  {
    GNUNET_break (0);
    return NULL;
  }
  GNUNET_assert (TALER_EC_NONE ==
                 test_wire_validate (tc,
                                     wire,
                                     NULL,
                                     &emsg));
  if (0 !=
      json_unpack_ex (wire,
		      &error,
		      0,
		      "{s:I}",
		      "account_number", &account_no))
  {
    GNUNET_break (0);
    return NULL;
  }

  eh = GNUNET_new (struct TALER_WIRE_ExecuteHandle);
  eh->cc = cc;
  eh->cc_cls = cc_cls;
  wire_s = GNUNET_STRINGS_data_to_string_alloc (&bf.wtid,
                                                sizeof (bf.wtid));
  eh->aaih = TALER_BANK_admin_add_incoming (tc->ctx,
                                            tc->bank_url,
                                            &tc->auth,
                                            exchange_base_url,
                                            wire_s,
                                            &amount,
                                            (uint64_t) tc->exchange_account_no,
					    (uint64_t) account_no,
                                            &execute_cb,
                                            eh);
  GNUNET_free (wire_s);
  json_decref (wire);
  if (NULL == eh->aaih)
  {
    GNUNET_break (0);
    GNUNET_free (eh);
    return NULL;
  }
  return eh;
}


/**
 * Abort execution of a wire transfer. For example, because we are
 * shutting down.  Note that if an execution is aborted, it may or
 * may not still succeed. The caller MUST run @e
 * execute_wire_transfer again for the same request as soon as
 * possilbe, to ensure that the request either ultimately succeeds
 * or ultimately fails. Until this has been done, the transaction is
 * in limbo (i.e. may or may not have been committed).
 *
 * @param cls the @e cls of this struct with the plugin-specific state
 * @param eh execution to cancel
 */
static void
test_execute_wire_transfer_cancel (void *cls,
                                   struct TALER_WIRE_ExecuteHandle *eh)
{
  TALER_BANK_admin_add_incoming_cancel (eh->aaih);
  GNUNET_free (eh);
}


/**
 * Handle for a #test_get_history() request.
 */
struct TALER_WIRE_HistoryHandle
{

  /**
   * Function to call with results.
   */
  TALER_WIRE_HistoryResultCallback hres_cb;

  /**
   * Closure for @e hres_cb.
   */
  void *hres_cb_cls;

  /**
   * Request to the bank.
   */
  struct TALER_BANK_HistoryHandle *hh;

};


/**
 * Function called with results from the bank about the transaction history.
 *
 * @param cls the `struct TALER_WIRE_HistoryHandle`
 * @param http_status HTTP response code, #MHD_HTTP_OK (200) for successful status request
 *                    0 if the bank's reply is bogus (fails to follow the protocol),
 *                    #MHD_HTTP_NO_CONTENT if there are no more results; on success the
 *                    last callback is always of this status (even if `abs(num_results)` were
 *                    already returned).
 * @param ec taler error code
 * @param dir direction of the transfer
 * @param serial_id monotonically increasing counter corresponding to the transaction
 * @param details details about the wire transfer
 * @param json detailed response from the HTTPD, or NULL if reply was not in JSON
 */
static void
bhist_cb (void *cls,
          unsigned int http_status,
          enum TALER_ErrorCode ec,
          enum TALER_BANK_Direction dir,
          uint64_t serial_id,
          const struct TALER_BANK_TransferDetails *details,
          const json_t *json)
{
  struct TALER_WIRE_HistoryHandle *whh = cls;
  uint64_t bserial_id = GNUNET_htonll (serial_id);
  struct TALER_WIRE_TransferDetails wd;

  switch (http_status) {
  case MHD_HTTP_OK:
    {
      char *subject;
      char *space;

      wd.amount = details->amount;
      wd.execution_date = details->execution_date;
      subject = GNUNET_strdup (details->wire_transfer_subject);
      space = strchr (subject, (int) ' ');
      if (NULL != space)
      {
        /* Space separates the actual wire transfer subject from the
           exchange base URL (if present, expected only for outgoing
           transactions).  So we cut the string off at the space. */
        *space = '\0';
      }
      /* NOTE: For a real bank, the subject should include a checksum! */
      if (GNUNET_OK !=
          GNUNET_STRINGS_string_to_data (subject,
                                         strlen (subject),
                                         &wd.wtid,
                                         sizeof (wd.wtid)))
      {
        /* Ill-formed wire subject, set binary version to all zeros
           and pass as a string, this time including the part after
           the space. */
        memset (&wd.wtid,
                0,
                sizeof (wd.wtid));
        wd.wtid_s = details->wire_transfer_subject;
      }
      else
      {
        wd.wtid_s = NULL;
      }
      GNUNET_free (subject);
      wd.account_details = details->account_details;

      if ( (NULL != whh->hres_cb) &&
           (GNUNET_OK !=
            whh->hres_cb (whh->hres_cb_cls,
                          TALER_EC_NONE,
                          dir,
                          &bserial_id,
                          sizeof (bserial_id),
                          &wd)) )
        whh->hres_cb = NULL;
      break;
    }
  case MHD_HTTP_NO_CONTENT:
    if (NULL != whh->hres_cb)
      (void) whh->hres_cb (whh->hres_cb_cls,
                           ec,
                           TALER_BANK_DIRECTION_NONE,
                           NULL,
                           0,
                           NULL);
    GNUNET_free (whh);
    break;
  default:
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Bank failed with HTTP status %u (EC: %u)\n",
                http_status,
                ec);
    if (NULL != whh->hres_cb)
      (void) whh->hres_cb (whh->hres_cb_cls,
                           ec,
                           TALER_BANK_DIRECTION_NONE,
                           NULL,
                           0,
                           NULL);
    GNUNET_free (whh);
    break;
  }
}


/**
 * Query transfer history of an account.  We use the variable-size
 * @a start_off to indicate which transfers we are interested in as
 * different banking systems may have different ways to identify
 * transfers.  The @a start_off value must thus match the value of
 * a `row_off` argument previously given to the @a hres_cb.  Use
 * NULL to query transfers from the beginning of time (with
 * positive @a num_results) or from the latest committed transfers
 * (with negative @a num_results).
 *
 * @param cls the @e cls of this struct with the plugin-specific state
 * @param direction what kinds of wire transfers should be returned
 * @param start_off from which row on do we want to get results, use NULL for the latest; exclusive
 * @param start_off_len number of bytes in @a start_off; must be `sizeof(uint64_t)`.
 * @param num_results how many results do we want; negative numbers to go into the past,
 *                    positive numbers to go into the future starting at @a start_row;
 *                    must not be zero.
 * @param hres_cb the callback to call with the transaction history
 * @param hres_cb_cls closure for the above callback
 */
static struct TALER_WIRE_HistoryHandle *
test_get_history (void *cls,
                  enum TALER_BANK_Direction direction,
                  const void *start_off,
                  size_t start_off_len,
                  int64_t num_results,
                  TALER_WIRE_HistoryResultCallback hres_cb,
                  void *hres_cb_cls)
{
  struct TestClosure *tc = cls;
  struct TALER_WIRE_HistoryHandle *whh;
  const uint64_t *start_off_b64;
  uint64_t start_row;

  if (0 == num_results)
  {
    GNUNET_break (0);
    return NULL;
  }
  if (TALER_BANK_DIRECTION_NONE == direction)
  {
    GNUNET_break (0);
    return NULL;
  }
  if ( (NULL != start_off) &&
       (sizeof (uint64_t) != start_off_len) )
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Wire plugin 'test' got start offset of wrong size (%llu instead of %llu)\n",
                (unsigned long long) start_off_len, (unsigned long long) sizeof (uint64_t));
    GNUNET_break (0);
    /* Probably something is wrong with the DB, some other component
     * wrote a wrong value to it.  Instead of completely stopping to work, 
     * we just scan from the beginning. */
    start_off = NULL;
  }
  if (NULL == start_off)
  {
    start_row = UINT64_MAX; /* no start row */
  }
  else
  {
    start_off_b64 = start_off;
    start_row = GNUNET_ntohll (*start_off_b64);
  }

  whh = GNUNET_new (struct TALER_WIRE_HistoryHandle);
  whh->hres_cb = hres_cb;
  whh->hres_cb_cls = hres_cb_cls;
  whh->hh = TALER_BANK_history (tc->ctx,
                                tc->bank_url,
                                &tc->auth,
                                (uint64_t) tc->exchange_account_no,
                                direction,
                                start_row,
                                num_results,
                                &bhist_cb,
                                whh);
  if (NULL == whh->hh)
  {
    GNUNET_break (0);
    GNUNET_free (whh);
    return NULL;
  }

  return whh;
}


/**
 * Cancel going over the account's history.
 *
 * @param cls the @e cls of this struct with the plugin-specific state
 * @param whh operation to cancel
 */
static void
test_get_history_cancel (void *cls,
			 struct TALER_WIRE_HistoryHandle *whh)
{
  TALER_BANK_history_cancel (whh->hh);
  GNUNET_free (whh);
}


/**
 * Context for a rejection operation.
 */
struct TALER_WIRE_RejectHandle
{
  /**
   * Function to call with the result.
   */
  TALER_WIRE_RejectTransferCallback rej_cb;

  /**
   * Closure for @e rej_cb.
   */
  void *rej_cb_cls;

  /**
   * Handle for the reject operation.
   */
  struct TALER_BANK_RejectHandle *brh;
};


/**
 * Callbacks of this type are used to serve the result of asking
 * the bank to reject an incoming wire transfer.
 *
 * @param cls closure
 * @param http_status HTTP response code, #MHD_HTTP_NO_CONTENT (204) for successful status request;
 *                    #MHD_HTTP_NOT_FOUND if the rowid is unknown;
 *                    0 if the bank's reply is bogus (fails to follow the protocol),
 * @param ec detailed error code
 */
static void
reject_cb (void *cls,
           unsigned int http_status,
           enum TALER_ErrorCode ec)
{
  struct TALER_WIRE_RejectHandle *rh = cls;

  rh->brh = NULL;
  rh->rej_cb (rh->rej_cb_cls,
              ec);
  GNUNET_free (rh);
}


/**
 * Reject an incoming wire transfer that was obtained from the
 * history. This function can be used to transfer funds back to
 * the sender if the WTID was malformed (i.e. due to a typo).
 *
 * Calling `reject_transfer` twice on the same wire transfer should
 * be idempotent, i.e. not cause the funds to be wired back twice.
 * Furthermore, the transfer should henceforth be removed from the
 * results returned by @e get_history.
 *
 * @param cls plugin's closure
 * @param start_off offset of the wire transfer in plugin-specific format
 * @param start_off_len number of bytes in @a start_off
 * @param rej_cb function to call with the result of the operation
 * @param rej_cb_cls closure for @a rej_cb
 * @return handle to cancel the operation
 */
static struct TALER_WIRE_RejectHandle *
test_reject_transfer (void *cls,
                      const void *start_off,
                      size_t start_off_len,
                      TALER_WIRE_RejectTransferCallback rej_cb,
                      void *rej_cb_cls)
{
  struct TestClosure *tc = cls;
  const uint64_t *rowid_b64 = start_off;
  struct TALER_WIRE_RejectHandle *rh;

  if (sizeof (uint64_t) != start_off_len)
  {
    GNUNET_break (0);
    return NULL;
  }
  rh = GNUNET_new (struct TALER_WIRE_RejectHandle);
  rh->rej_cb = rej_cb;
  rh->rej_cb_cls = rej_cb_cls;
  rh->brh = TALER_BANK_reject (tc->ctx,
                               tc->bank_url,
                               &tc->auth,
                               (uint64_t) tc->exchange_account_no,
                               GNUNET_ntohll (*rowid_b64),
                               &reject_cb,
                               rh);
  if (NULL == rh->brh)
  {
    GNUNET_free (rh);
    return NULL;
  }
  return rh;
}


/**
 * Cancel ongoing reject operation.  Note that the rejection may still
 * proceed. Basically, if this function is called, the rejection may
 * have happened or not.  This function is usually used during shutdown
 * or system upgrades.  At a later point, the application must call
 * @e reject_transfer again for this wire transfer, unless the
 * @e get_history shows that the wire transfer no longer exists.
 *
 * @param cls plugins' closure
 * @param rh operation to cancel
 * @return closure of the callback of the operation
 */
static void *
test_reject_transfer_cancel (void *cls,
                             struct TALER_WIRE_RejectHandle *rh)
{
  void *ret = rh->rej_cb_cls;

  if (NULL != rh->brh)
    TALER_BANK_reject_cancel (rh->brh);
  GNUNET_free (rh);
  return ret;
}


/**
 * Initialize test-wire subsystem.
 *
 * @param cls a configuration instance
 * @return NULL on error, otherwise a `struct TALER_WIRE_Plugin`
 */
void *
libtaler_plugin_wire_test_init (void *cls)
{
  struct GNUNET_CONFIGURATION_Handle *cfg = cls;
  struct TestClosure *tc;
  struct TALER_WIRE_Plugin *plugin;
  char *user;
  char *pass;

  tc = GNUNET_new (struct TestClosure);
  if (NULL != cfg)
  {
    if (GNUNET_OK !=
        GNUNET_CONFIGURATION_get_value_string (cfg,
                                               "exchange-wire-test",
                                               "BANK_URL",
                                               &tc->bank_url))
    {
      GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR,
                                 "exchange-wire-test",
                                 "BANK_URL");
      GNUNET_free (tc);
      return NULL;
    }
    if (GNUNET_OK !=
        GNUNET_CONFIGURATION_get_value_number (cfg,
                                               "exchange-wire-test",
                                               "EXCHANGE_ACCOUNT_NUMBER",
                                               &tc->exchange_account_no))
    {
      GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR,
                                 "exchange-wire-test",
                                 "EXCHANGE_ACCOUNT_NUMBER");
      GNUNET_free (tc->bank_url);
      GNUNET_free (tc);
      return NULL;
    }
    if (GNUNET_OK !=
        GNUNET_CONFIGURATION_get_value_string (cfg,
                                               "taler",
                                               "CURRENCY",
                                               &tc->currency))
    {
      GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR,
                                 "taler",
                                 "CURRENCY");
      GNUNET_free (tc->bank_url);
      GNUNET_free (tc);
      return NULL;
    }
    if (GNUNET_OK !=
        GNUNET_CONFIGURATION_get_value_string (cfg,
                                               "exchange-wire-test",
                                               "USERNAME",
                                               &user))
    {
      GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR,
                                 "exchange-wire-test",
                                 "USERNAME");
      GNUNET_free (tc->bank_url);
      GNUNET_free (tc);
      return NULL;
    }
    if (GNUNET_OK !=
        GNUNET_CONFIGURATION_get_value_string (cfg,
                                               "exchange-wire-test",
                                               "PASSWORD",
                                               &pass))
    {
      GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR,
                                 "exchange-wire-test",
                                 "PASSWORD");
      GNUNET_free (tc->bank_url);
      GNUNET_free (tc);
      GNUNET_free (user);
      return NULL;
    }
    tc->auth.method = TALER_BANK_AUTH_BASIC;
    tc->auth.details.basic.username = user;
    tc->auth.details.basic.password = pass;
    tc->ctx = GNUNET_CURL_init (&GNUNET_CURL_gnunet_scheduler_reschedule,
                                &tc->rc);
    tc->rc = GNUNET_CURL_gnunet_rc_create (tc->ctx);
    if (NULL == tc->ctx)
    {
      GNUNET_break (0);
      GNUNET_free (tc->currency);
      GNUNET_free (tc->bank_url);
      GNUNET_free (tc->auth.details.basic.username);
      GNUNET_free (tc->auth.details.basic.password);
      GNUNET_free (tc);
      return NULL;
    }
  }
  plugin = GNUNET_new (struct TALER_WIRE_Plugin);
  plugin->cls = tc;
  plugin->amount_round = &test_amount_round;
  plugin->get_wire_details = &test_get_wire_details;
  plugin->sign_wire_details = &test_sign_wire_details;
  plugin->wire_validate = &test_wire_validate;
  plugin->prepare_wire_transfer = &test_prepare_wire_transfer;
  plugin->prepare_wire_transfer_cancel = &test_prepare_wire_transfer_cancel;
  plugin->execute_wire_transfer = &test_execute_wire_transfer;
  plugin->execute_wire_transfer_cancel = &test_execute_wire_transfer_cancel;
  plugin->get_history = &test_get_history;
  plugin->get_history_cancel = &test_get_history_cancel;
  plugin->reject_transfer = &test_reject_transfer;
  plugin->reject_transfer_cancel = &test_reject_transfer_cancel;
  return plugin;
}


/**
 * Shutdown Test wire subsystem.
 *
 * @param cls a `struct TALER_WIRE_Plugin`
 * @return NULL (always)
 */
void *
libtaler_plugin_wire_test_done (void *cls)
{
  struct TALER_WIRE_Plugin *plugin = cls;
  struct TestClosure *tc = plugin->cls;

  if (NULL != tc->ctx)
  {
    GNUNET_CURL_fini (tc->ctx);
    tc->ctx = NULL;
  }
  if (NULL != tc->rc)
  {
    GNUNET_CURL_gnunet_rc_destroy (tc->rc);
    tc->rc = NULL;
  }
  switch (tc->auth.method)
  {
  case TALER_BANK_AUTH_NONE:
    break;
  case TALER_BANK_AUTH_BASIC:
    if (NULL != tc->auth.details.basic.username)
    {
      GNUNET_free (tc->auth.details.basic.username);
      tc->auth.details.basic.username = NULL;
    }
    if (NULL != tc->auth.details.basic.password)
    {
      GNUNET_free (tc->auth.details.basic.password);
      tc->auth.details.basic.password = NULL;
    }
    break;
  }
  GNUNET_free_non_null (tc->currency);
  GNUNET_free_non_null (tc->bank_url);
  GNUNET_free (tc);
  GNUNET_free (plugin);
  return NULL;
}

/* end of plugin_wire_test.c */