aboutsummaryrefslogtreecommitdiff
path: root/src/lib/auditor_api_handle.c
blob: 70bf6f7156651b165a8ca888cc28e4f6a762d184 (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
/*
  This file is part of TALER
  Copyright (C) 2014-2018 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 auditor-lib/auditor_api_handle.c
 * @brief Implementation of the "handle" component of the auditor's HTTP API
 * @author Sree Harsha Totakura <sreeharsha@totakura.in>
 * @author Christian Grothoff
 */
#include "platform.h"
#include <microhttpd.h>
#include <gnunet/gnunet_curl_lib.h>
#include "taler_json_lib.h"
#include "taler_auditor_service.h"
#include "taler_signatures.h"
#include "auditor_api_handle.h"
#include "auditor_api_curl_defaults.h"
#include "backoff.h"

/**
 * Which revision of the Taler auditor 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_AUDITOR_Handle`
 */
enum AuditorHandleState
{
  /**
   * Just allocated.
   */
  MHS_INIT = 0,

  /**
   * Obtained the auditor's versioning data and version.
   */
  MHS_VERSION = 1,

  /**
   * Failed to initialize (fatal).
   */
  MHS_FAILED = 2
};


/**
 * Data for the request to get the /version of a auditor.
 */
struct VersionRequest;


/**
 * Handle to the auditor
 */
struct TALER_AUDITOR_Handle
{
  /**
   * The context of this handle
   */
  struct GNUNET_CURL_Context *ctx;

  /**
   * The URL of the auditor (i.e. "http://auditor.taler.net/")
   */
  char *url;

  /**
   * Function to call with the auditor's certification data,
   * NULL if this has already been done.
   */
  TALER_AUDITOR_VersionCallback version_cb;

  /**
   * Closure to pass to @e version_cb.
   */
  void *version_cb_cls;

  /**
   * Data for the request to get the /version of a auditor,
   * NULL once we are past stage #MHS_INIT.
   */
  struct VersionRequest *vr;

  /**
   * Task for retrying /version request.
   */
  struct GNUNET_SCHEDULER_Task *retry_task;

  /**
   * /version data of the auditor, only valid if
   * @e handshake_complete is past stage #MHS_VERSION.
   */
  struct TALER_AUDITOR_VersionInformation vi;

  /**
   * Retry /version frequency.
   */
  struct GNUNET_TIME_Relative retry_delay;

  /**
   * Stage of the auditor's initialization routines.
   */
  enum AuditorHandleState state;

};


/* ***************** Internal /version fetching ************* */

/**
 * Data for the request to get the /version of a auditor.
 */
struct VersionRequest
{
  /**
   * The connection to auditor this request handle will use
   */
  struct TALER_AUDITOR_Handle *auditor;

  /**
   * The url for this handle
   */
  char *url;

  /**
   * Entry for this request with the `struct GNUNET_CURL_Context`.
   */
  struct GNUNET_CURL_Job *job;

};


/**
 * Release memory occupied by a version request.
 * Note that this does not cancel the request
 * itself.
 *
 * @param vr request to free
 */
static void
free_version_request (struct VersionRequest *vr)
{
  GNUNET_free (vr->url);
  GNUNET_free (vr);
}


/**
 * Free version data object.
 *
 * @param vi data to free (pointer itself excluded)
 */
static void
free_version_info (struct TALER_AUDITOR_VersionInformation *vi)
{
  GNUNET_free_non_null (vi->version);
  vi->version = NULL;
}


/**
 * Decode the JSON in @a resp_obj from the /version response and store the data
 * in the @a key_data.
 *
 * @param[in] resp_obj JSON object to parse
 * @param check_sig #GNUNET_YES if we should check the signature
 * @param[out] vi where to store the results we decoded
 * @param[out] vc where to store version compatibility data
 * @return #GNUNET_OK on success, #GNUNET_SYSERR on error (malformed JSON)
 */
static int
decode_version_json (const json_t *resp_obj,
                     int check_sig,
                     struct TALER_AUDITOR_VersionInformation *vi,
                     enum TALER_AUDITOR_VersionCompatibility *vc)
{
  unsigned int age;
  unsigned int revision;
  unsigned int current;
  const char *ver;
  struct GNUNET_JSON_Specification spec[] = {
    GNUNET_JSON_spec_string ("version",
			     &ver),
    GNUNET_JSON_spec_fixed_auto ("auditor_public_key",
				 &vi->auditor_pub),
    GNUNET_JSON_spec_end()
  };

  if (JSON_OBJECT != json_typeof (resp_obj))
  {
    GNUNET_break_op (0);
    return GNUNET_SYSERR;
  }
  /* check the version */
  if (GNUNET_OK !=
      GNUNET_JSON_parse (resp_obj,
			 spec,
			 NULL, NULL))
  {
    GNUNET_break_op (0);
    return GNUNET_SYSERR;
  }
  if (3 != sscanf (ver,
		   "%u:%u:%u",
		   &current,
		   &revision,
		   &age))
  {
    GNUNET_break_op (0);
    return GNUNET_SYSERR;
  }
  vi->version = GNUNET_strdup (ver);
  *vc = TALER_AUDITOR_VC_MATCH;
  if (TALER_PROTOCOL_CURRENT < current)
  {
    *vc |= TALER_AUDITOR_VC_NEWER;
    if (TALER_PROTOCOL_CURRENT < current - age)
      *vc |= TALER_AUDITOR_VC_INCOMPATIBLE;
  }
  if (TALER_PROTOCOL_CURRENT > current)
  {
    *vc |= TALER_AUDITOR_VC_OLDER;
    if (TALER_PROTOCOL_CURRENT - TALER_PROTOCOL_AGE > current)
      *vc |= TALER_AUDITOR_VC_INCOMPATIBLE;
  }
  return GNUNET_OK;
}

/**
 * Initiate download of /version from the auditor.
 *
 * @param cls auditor where to download /version from
 */
static void
request_version (void *cls);


/**
 * Callback used when downloading the reply to a /version request
 * is complete.
 *
 * @param cls the `struct VersionRequest`
 * @param response_code HTTP response code, 0 on error
 * @param resp_obj parsed JSON result, NULL on error
 */
static void
version_completed_cb (void *cls,
		      long response_code,
		      const void *gresp_obj)
{
  const json_t *resp_obj = gresp_obj;
  struct VersionRequest *vr = cls;
  struct TALER_AUDITOR_Handle *auditor = vr->auditor;
  enum TALER_AUDITOR_VersionCompatibility vc;

  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
              "Received version from URL `%s' with status %ld.\n",
              vr->url,
              response_code);
  vc = TALER_AUDITOR_VC_PROTOCOL_ERROR;
  switch (response_code)
  {
  case 0:
  case MHD_HTTP_INTERNAL_SERVER_ERROR:
    free_version_request (vr);
    auditor->vr = NULL;
    GNUNET_assert (NULL == auditor->retry_task);
    auditor->retry_delay = EXCHANGE_LIB_BACKOFF (auditor->retry_delay);
    auditor->retry_task = GNUNET_SCHEDULER_add_delayed (auditor->retry_delay,
                                                        &request_version,
                                                        auditor);
    return;
  case MHD_HTTP_OK:
    if (NULL == resp_obj)
    {
      GNUNET_break_op (0);
      TALER_LOG_WARNING ("NULL body for a 200-OK /version\n");
      response_code = 0;
      break;
    }
    if (GNUNET_OK !=
        decode_version_json (resp_obj,
                             GNUNET_YES,
                             &auditor->vi,
                             &vc))
    {
      GNUNET_break_op (0);
      response_code = 0;
      break;
    }
    auditor->retry_delay = GNUNET_TIME_UNIT_ZERO;
    break;
  default:
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Unexpected response code %u\n",
                (unsigned int) response_code);
    break;
  }
  if (MHD_HTTP_OK != response_code)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
		"/version failed for auditor %p: %u!\n",
		auditor,
		(unsigned int) response_code);
    auditor->vr = NULL;
    free_version_request (vr);
    auditor->state = MHS_FAILED;
    free_version_info (&auditor->vi);
    /* notify application that we failed */
    auditor->version_cb (auditor->version_cb_cls,
			 NULL,
			 vc);
    return;
  }

  auditor->vr = NULL;
  free_version_request (vr);
  TALER_LOG_DEBUG ("Switching auditor state to 'version'\n");
  auditor->state = MHS_VERSION;
  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
              "Auditor %p is now READY!\n",
              auditor);
  /* notify application about the key information */
  auditor->version_cb (auditor->version_cb_cls,
                       &auditor->vi,
                       vc);
}


/* ********************* library internal API ********* */


/**
 * Get the context of a auditor.
 *
 * @param h the auditor handle to query
 * @return ctx context to execute jobs in
 */
struct GNUNET_CURL_Context *
MAH_handle_to_context (struct TALER_AUDITOR_Handle *h)
{
  return h->ctx;
}


/**
 * Check if the handle is ready to process requests.
 *
 * @param h the auditor handle to query
 * @return #GNUNET_YES if we are ready, #GNUNET_NO if not
 */
int
MAH_handle_is_ready (struct TALER_AUDITOR_Handle *h)
{
  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
              "Checking if auditor %p is now ready: %s\n",
              h,
	      (MHD_VERSION == h->state) ? "yes" : "no");
  return (MHS_VERSION == h->state) ? GNUNET_YES : GNUNET_NO;
}


/**
 * Obtain the URL to use for an API request.
 *
 * @param h handle for the auditor
 * @param path Taler API path (i.e. "/deposit-confirmation")
 * @return the full URL to use with cURL
 */
char *
MAH_path_to_url (struct TALER_AUDITOR_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 auditor (i.e. "http://auditor/")
 * @param path Taler API path (i.e. "/deposit-confirmation")
 * @return the full URL 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;
}


/* ********************* public API ******************* */


/**
 * Initialise a connection to the auditor. Will connect to the
 * auditor and obtain information about the auditor's master public
 * key and the auditor's auditor.  The respective information will
 * be passed to the @a version_cb once available, and all future
 * interactions with the auditor will be checked to be signed
 * (where appropriate) by the respective master key.
 *
 * @param ctx the context
 * @param url HTTP base URL for the auditor
 * @param version_cb function to call with the
 *        auditor's version information
 * @param version_cb_cls closure for @a version_cb
 * @return the auditor handle; NULL upon error
 */
struct TALER_AUDITOR_Handle *
TALER_AUDITOR_connect (struct GNUNET_CURL_Context *ctx,
		       const char *url,
		       TALER_AUDITOR_VersionCallback version_cb,
		       void *version_cb_cls)
{
  struct TALER_AUDITOR_Handle *auditor;

  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
              "Connecting to auditor at URL `%s'.\n",
              url);
  auditor = GNUNET_new (struct TALER_AUDITOR_Handle);
  auditor->ctx = ctx;
  auditor->url = GNUNET_strdup (url);
  auditor->version_cb = version_cb;
  auditor->version_cb_cls = version_cb_cls;
  auditor->retry_task = GNUNET_SCHEDULER_add_now (&request_version,
						  auditor);
  return auditor;
}


/**
 * Initiate download of /version from the auditor.
 *
 * @param cls auditor where to download /version from
 */
static void
request_version (void *cls)
{
  struct TALER_AUDITOR_Handle *auditor = cls;
  struct VersionRequest *vr;
  CURL *eh;

  auditor->retry_task = NULL;
  GNUNET_assert (NULL == auditor->vr);
  vr = GNUNET_new (struct VersionRequest);
  vr->auditor = auditor;
  vr->url = MAH_path_to_url (auditor,
			     "/version");
  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
              "Requesting auditor version with URL `%s'.\n",
              vr->url);
  eh = TAL_curl_easy_get (vr->url);
  GNUNET_assert (CURLE_OK ==
                 curl_easy_setopt (eh,
                                   CURLOPT_TIMEOUT,
                                   (long) 300));
  vr->job = GNUNET_CURL_job_add (auditor->ctx,
                                 eh,
                                 GNUNET_NO,
                                 &version_completed_cb,
                                 vr);
  auditor->vr = vr;
}


/**
 * Disconnect from the auditor
 *
 * @param auditor the auditor handle
 */
void
TALER_AUDITOR_disconnect (struct TALER_AUDITOR_Handle *auditor)
{
  if (NULL != auditor->vr)
  {
    GNUNET_CURL_job_cancel (auditor->vr->job);
    free_version_request (auditor->vr);
    auditor->vr = NULL;
  }
  free_version_info (&auditor->vi);
  if (NULL != auditor->retry_task)
  {
    GNUNET_SCHEDULER_cancel (auditor->retry_task);
    auditor->retry_task = NULL;
  }
  GNUNET_free (auditor->url);
  GNUNET_free (auditor);
}


/* end of auditor_api_handle.c */