summaryrefslogtreecommitdiff
path: root/src/dns/gnunet-zonewalk.c
blob: e05a04f360eea48e3ec9f29ddc6cff8daad822f4 (plain) (blame)
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
/*
     This file is part of GNUnet
     Copyright (C) 2018 GNUnet e.V.

     GNUnet 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 of the License,
     or (at your option) any later version.

     GNUnet 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
     Affero General Public License for more details.
*/

/**
 * @file src/dns/gnunet-zoneimport.c
 * @brief import a DNS zone for analysis, brute force
 * @author Christian Grothoff
 */
#include "platform.h"
#include <gnunet_util_lib.h>
#include <gnunet_dnsstub_lib.h>
#include <gnunet_dnsparser_lib.h>

/**
 * Request we should make.
 */
struct Request
{
  /**
   * Requests are kept in a DLL.
   */
  struct Request *next;

  /**
   * Requests are kept in a DLL.
   */
  struct Request *prev;

  /**
   * Socket used to make the request, NULL if not active.
   */
  struct GNUNET_DNSSTUB_RequestSocket *rs;

  /**
   * Raw DNS query.
   */
  void *raw;

  /**
   * Number of bytes in @e raw.
   */
  size_t raw_len;

  /**
   * Hostname we are resolving.
   */
  char *hostname;

  /**
   * When did we last issue this request?
   */
  time_t time;

  /**
   * How often did we issue this query?
   */
  int issue_num;

  /**
   * random 16-bit DNS query identifier.
   */
  uint16_t id;
};


/**
 * Context for DNS resolution.
 */
static struct GNUNET_DNSSTUB_Context *ctx;

/**
 * The number of queries that are outstanding
 */
static unsigned int pending;

/**
 * Number of lookups we performed overall.
 */
static unsigned int lookups;

/**
 * Number of lookups that failed.
 */
static unsigned int failures;

/**
 * Number of records we found.
 */
static unsigned int records;

/**
 * Head of DLL of all requests to perform.
 */
static struct Request *req_head;

/**
 * Tail of DLL of all requests to perform.
 */
static struct Request *req_tail;

/**
 * Main task.
 */
static struct GNUNET_SCHEDULER_Task *t;

/**
 * Maximum number of queries pending at the same time.
 */
#define THRESH 20

/**
 * TIME_THRESH is in usecs.  How quickly do we submit fresh queries.
 * Used as an additional throttle.
 */
#define TIME_THRESH 10

/**
 * How often do we retry a query before giving up for good?
 */
#define MAX_RETRIES 5


/**
 * We received @a rec for @a req. Remember the answer.
 *
 * @param req request
 * @param rec response
 */
static void
process_record (struct Request *req,
                struct GNUNET_DNSPARSER_Record *rec)
{
  char buf[INET6_ADDRSTRLEN];

  records++;
  switch (rec->type)
  {
  case GNUNET_DNSPARSER_TYPE_A:
    fprintf (stdout,
             "%s A %s\n",
             req->hostname,
             inet_ntop (AF_INET,
                        rec->data.raw.data,
                        buf,
                        sizeof (buf)));
    break;
  case GNUNET_DNSPARSER_TYPE_AAAA:
    fprintf (stdout,
             "%s AAAA %s\n",
             req->hostname,
             inet_ntop (AF_INET6,
                        rec->data.raw.data,
                        buf,
                        sizeof (buf)));
    break;
  case GNUNET_DNSPARSER_TYPE_NS:
    fprintf (stdout,
             "%s NS %s\n",
             req->hostname,
             rec->data.hostname);
    break;
  case GNUNET_DNSPARSER_TYPE_CNAME:
    fprintf (stdout,
             "%s CNAME %s\n",
             req->hostname,
             rec->data.hostname);
    break;
  case GNUNET_DNSPARSER_TYPE_MX:
    fprintf (stdout,
             "%s MX %u %s\n",
             req->hostname,
             (unsigned int) rec->data.mx->preference,
             rec->data.mx->mxhost);
    break;
  case GNUNET_DNSPARSER_TYPE_SOA:
    fprintf (stdout,
             "%s SOA %s %s %u %u %u %u %u\n",
             req->hostname,
             rec->data.soa->mname,
             rec->data.soa->rname,
             (unsigned int) rec->data.soa->serial,
             (unsigned int) rec->data.soa->refresh,
             (unsigned int) rec->data.soa->retry,
             (unsigned int) rec->data.soa->expire,
             (unsigned int) rec->data.soa->minimum_ttl);
    break;
  case GNUNET_DNSPARSER_TYPE_SRV:
    fprintf (stdout,
             "%s SRV %s %u %u %u\n",
             req->hostname,
             rec->data.srv->target,
             rec->data.srv->priority,
             rec->data.srv->weight,
             rec->data.srv->port);
    break;
  case GNUNET_DNSPARSER_TYPE_PTR:
    fprintf (stdout,
             "%s PTR %s\n",
             req->hostname,
             rec->data.hostname);
    break;
  case GNUNET_DNSPARSER_TYPE_TXT:
    fprintf (stdout,
             "%s TXT %.*s\n",
             req->hostname,
             (int) rec->data.raw.data_len,
             (char *) rec->data.raw.data);
    break;
  case GNUNET_DNSPARSER_TYPE_DNAME:
    fprintf (stdout,
             "%s DNAME %s\n",
             req->hostname,
             rec->data.hostname);
    break;

    /* obscure records */
  case GNUNET_DNSPARSER_TYPE_AFSDB:
  case GNUNET_DNSPARSER_TYPE_NAPTR:
  case GNUNET_DNSPARSER_TYPE_APL:
  case GNUNET_DNSPARSER_TYPE_DHCID:
  case GNUNET_DNSPARSER_TYPE_HIP:
  case GNUNET_DNSPARSER_TYPE_LOC:
  case GNUNET_DNSPARSER_TYPE_RP:
  case GNUNET_DNSPARSER_TYPE_TKEY:
  case GNUNET_DNSPARSER_TYPE_TSIG:
  case GNUNET_DNSPARSER_TYPE_URI:
  case GNUNET_DNSPARSER_TYPE_TA:

    /* DNSSEC */
  case GNUNET_DNSPARSER_TYPE_DS:
  case GNUNET_DNSPARSER_TYPE_RRSIG:
  case GNUNET_DNSPARSER_TYPE_NSEC:
  case GNUNET_DNSPARSER_TYPE_DNSKEY:
  case GNUNET_DNSPARSER_TYPE_NSEC3:
  case GNUNET_DNSPARSER_TYPE_NSEC3PARAM:
  case GNUNET_DNSPARSER_TYPE_CDS:
  case GNUNET_DNSPARSER_TYPE_CDNSKEY:

    /* DNSSEC payload */
  case GNUNET_DNSPARSER_TYPE_CERT:
  case GNUNET_DNSPARSER_TYPE_SSHFP:
  case GNUNET_DNSPARSER_TYPE_IPSECKEY:
  case GNUNET_DNSPARSER_TYPE_TLSA:
  case GNUNET_DNSPARSER_TYPE_OPENPGPKEY:

    /* obsolete records */
  case GNUNET_DNSPARSER_TYPE_SIG:
  case GNUNET_DNSPARSER_TYPE_KEY:
  case GNUNET_DNSPARSER_TYPE_KX:
    {
      char *base32;

      base32 = GNUNET_STRINGS_data_to_string_alloc (rec->data.raw.data,
                                                    rec->data.raw.data_len);
      fprintf (stdout,
               "%s (%u) %s\n",
               req->hostname,
               rec->type,
               base32);
      GNUNET_free (base32);
    }
    break;
  default:
    fprintf (stderr,
             "Unsupported type %u\n",
             (unsigned int) rec->type);
    break;
  }
}


/**
 * Function called with the result of a DNS resolution.
 *
 * @param cls closure with the `struct Request`
 * @param dns dns response, never NULL
 * @param dns_len number of bytes in @a dns
 */
static void
process_result (void *cls,
                const struct GNUNET_TUN_DnsHeader *dns,
                size_t dns_len)
{
  struct Request *req = cls;
  struct GNUNET_DNSPARSER_Packet *p;

  if (NULL == dns)
  {
    /* stub gave up */
    pending--;
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Stub gave up on DNS reply for `%s'\n",
                req->hostname);
    GNUNET_CONTAINER_DLL_remove (req_head,
                                 req_tail,
                                 req);
    if (req->issue_num > MAX_RETRIES)
    {
      failures++;
      GNUNET_free (req->hostname);
      GNUNET_free (req->raw);
      GNUNET_free (req);
      return;
    }
    GNUNET_CONTAINER_DLL_insert_tail (req_head,
                                      req_tail,
                                      req);
    req->rs = NULL;
    return;
  }
  if (req->id != dns->id)
    return;
  pending--;
  GNUNET_DNSSTUB_resolve_cancel (req->rs);
  req->rs = NULL;
  GNUNET_CONTAINER_DLL_remove (req_head,
                               req_tail,
                               req);
  p = GNUNET_DNSPARSER_parse ((const char *) dns,
                              dns_len);
  if (NULL == p)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Failed to parse DNS reply for `%s'\n",
                req->hostname);
    if (req->issue_num > MAX_RETRIES)
    {
      failures++;
      GNUNET_free (req->hostname);
      GNUNET_free (req->raw);
      GNUNET_free (req);
      return;
    }
    GNUNET_CONTAINER_DLL_insert_tail (req_head,
                                      req_tail,
                                      req);
    return;
  }
  for (unsigned int i=0;i<p->num_answers;i++)
  {
    struct GNUNET_DNSPARSER_Record *rs = &p->answers[i];

    process_record (req,
                    rs);
  }
  for (unsigned int i=0;i<p->num_authority_records;i++)
  {
    struct GNUNET_DNSPARSER_Record *rs = &p->authority_records[i];

    process_record (req,
                    rs);
  }
  for (unsigned int i=0;i<p->num_additional_records;i++)
  {
    struct GNUNET_DNSPARSER_Record *rs = &p->additional_records[i];

    process_record (req,
                    rs);
  }
  GNUNET_DNSPARSER_free_packet (p);
  GNUNET_free (req->hostname);
  GNUNET_free (req->raw);
  GNUNET_free (req);
}


/**
 * Submit a request to DNS unless we need to slow down because
 * we are at the rate limit.
 *
 * @param req request to submit
 * @return #GNUNET_OK if request was submitted
 *         #GNUNET_NO if request was already submitted
 *         #GNUNET_SYSERR if we are at the rate limit
 */
static int
submit_req (struct Request *req)
{
  static struct timeval last_request;
  struct timeval now;

  if (NULL != req->rs)
    return GNUNET_NO; /* already submitted */
  gettimeofday (&now,
                NULL);
  if ( ( ( (now.tv_sec - last_request.tv_sec) == 0) &&
         ( (now.tv_usec - last_request.tv_usec) < TIME_THRESH) ) ||
       (pending >= THRESH) )
    return GNUNET_SYSERR;
  GNUNET_assert (NULL == req->rs);
  req->rs = GNUNET_DNSSTUB_resolve (ctx,
                                    req->raw,
                                    req->raw_len,
                                    &process_result,
                                    req);
  GNUNET_assert (NULL != req->rs);
  req->issue_num++;
  last_request = now;
  lookups++;
  pending++;
  req->time = time (NULL);
  return GNUNET_OK;
}


/**
 * Process as many requests as possible from the queue.
 *
 * @param cls NULL
 */
static void
process_queue(void *cls)
{
  (void) cls;
  t = NULL;
  for (struct Request *req = req_head;
       NULL != req;
       req = req->next)
  {
    if (GNUNET_SYSERR == submit_req (req))
      break;
  }
  if (NULL != req_head)
    t = GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_MILLISECONDS,
                                  &process_queue,
                                  NULL);
  else
    GNUNET_SCHEDULER_shutdown ();
}


/**
 * Clean up and terminate the process.
 *
 * @param cls NULL
 */
static void
do_shutdown (void *cls)
{
  (void) cls;
  if (NULL != t)
  {
    GNUNET_SCHEDULER_cancel (t);
    t = NULL;
  }
  GNUNET_DNSSTUB_stop (ctx);
  ctx = NULL;
}


/**
 * Process requests from the queue, then if the queue is
 * not empty, try again.
 *
 * @param cls NULL
 */
static void
run (void *cls)
{
  (void) cls;

  GNUNET_SCHEDULER_add_shutdown (&do_shutdown,
                                 NULL);
  t = GNUNET_SCHEDULER_add_now (&process_queue,
                                NULL);
}


/**
 * Add @a hostname to the list of requests to be made.
 *
 * @param hostname name to resolve
 */
static void
queue (const char *hostname)
{
  struct GNUNET_DNSPARSER_Packet p;
  struct GNUNET_DNSPARSER_Query q;
  struct Request *req;
  char *raw;
  size_t raw_size;

  if (GNUNET_OK !=
      GNUNET_DNSPARSER_check_name (hostname))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Refusing invalid hostname `%s'\n",
                hostname);
    return;
  }
  q.name = (char *) hostname;
  q.type = GNUNET_DNSPARSER_TYPE_NS;
  q.dns_traffic_class = GNUNET_TUN_DNS_CLASS_INTERNET;

  memset (&p,
          0,
          sizeof (p));
  p.num_queries = 1;
  p.queries = &q;
  p.id = (uint16_t) GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE,
                                              UINT16_MAX);

  if (GNUNET_OK !=
      GNUNET_DNSPARSER_pack (&p,
                             UINT16_MAX,
                             &raw,
                             &raw_size))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Failed to pack query for hostname `%s'\n",
                hostname);
    return;
  }

  req = GNUNET_new (struct Request);
  req->hostname = strdup (hostname);
  req->raw = raw;
  req->raw_len = raw_size;
  req->id = p.id;
  GNUNET_CONTAINER_DLL_insert_tail (req_head,
                                    req_tail,
                                    req);
}


/**
 * Call with IP address of resolver to query.
 *
 * @param argc should be 2
 * @param argv[1] should contain IP address
 * @return 0 on success
 */
int
main (int argc,
      char **argv)
{
  char hn[256];

  if (2 != argc)
  {
    fprintf (stderr,
             "Missing required configuration argument\n");
    return -1;
  }
  ctx = GNUNET_DNSSTUB_start (256);
  if (NULL == ctx)
  {
    fprintf (stderr,
             "Failed to initialize GNUnet DNS STUB\n");
    return 1;
  }
  if (GNUNET_OK !=
      GNUNET_DNSSTUB_add_dns_ip (ctx,
                                 argv[1]))
  {
    fprintf (stderr,
             "Failed to use `%s' for DNS resolver\n",
             argv[1]);
    return 1;
  }

  while (NULL !=
         fgets (hn,
                sizeof (hn),
                stdin))
  {
    if (strlen(hn) > 0)
      hn[strlen(hn)-1] = '\0'; /* eat newline */
    queue (hn);
  }
  GNUNET_SCHEDULER_run (&run,
                        NULL);
  fprintf (stderr,
           "Did %u lookups, found %u records, %u lookups failed, %u pending on shutdown\n",
           lookups,
           records,
           failures,
           pending);
  return 0;
}