aboutsummaryrefslogtreecommitdiff
path: root/src/gns/gnunet-dns2gns.c
blob: 0e347ca7e2252049acdc91f6e6940e8c685a1863 (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
/*
     This file is part of GNUnet.
     (C) 2012-2013 Christian Grothoff (and other contributing authors)

     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, 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
     General Public License for more details.

     You should have received a copy of the GNU General Public License
     along with GNUnet; see the file COPYING.  If not, write to the
     Free Software Foundation, Inc., 59 Temple Place - Suite 330,
     Boston, MA 02111-1307, USA.
*/
/**
 * @file gnunet-dns2gns.c
 * @brief DNS server that translates DNS requests to GNS
 * @author Christian Grothoff
 */
#include "platform.h"
#include <gnunet_util_lib.h>
#include <gnunet_dnsparser_lib.h>
#include <gnunet_gns_service.h>
#include <gnunet_identity_service.h>
#include <gnunet_dnsstub_lib.h>
#include "gns.h"

/**
 * Timeout for DNS requests.
 */
#define TIMEOUT GNUNET_TIME_UNIT_MINUTES

/**
 * Default suffix
 */
#define DNS_SUFFIX ".zkey.eu"

/**
 * FCFS suffix
 */
#define FCFS_SUFFIX "fcfs.zkey.eu"

/**
 * Data kept per request.
 */
struct Request
{
  /**
   * Socket to use for sending the reply.
   */
  struct GNUNET_NETWORK_Handle *lsock;

  /**
   * Destination address to use.
   */
  const void *addr;

  /**
   * Initially, this is the DNS request, it will then be
   * converted to the DNS response.
   */
  struct GNUNET_DNSPARSER_Packet *packet;

  /**
   * Our GNS request handle.
   */
  struct GNUNET_GNS_LookupRequest *lookup;

  /**
   * Our DNS request handle
   */
  struct GNUNET_DNSSTUB_RequestSocket *dns_lookup;

  /**
   * Task run on timeout or shutdown to clean up without
   * response.
   */
  struct GNUNET_SCHEDULER_Task * timeout_task;

  /**
   * Number of bytes in 'addr'.
   */
  size_t addr_len;

};


/**
 * Handle to GNS resolver.
 */
struct GNUNET_GNS_Handle *gns;

/**
 * Stub resolver
 */
struct GNUNET_DNSSTUB_Context *dns_stub;

/**
 * Listen socket for IPv4.
 */
static struct GNUNET_NETWORK_Handle *listen_socket4;

/**
 * Listen socket for IPv6.
 */
static struct GNUNET_NETWORK_Handle *listen_socket6;

/**
 * Task for IPv4 socket.
 */
static struct GNUNET_SCHEDULER_Task * t4;

/**
 * Task for IPv6 socket.
 */
static struct GNUNET_SCHEDULER_Task * t6;

/**
 * DNS suffix, suffix of this gateway in DNS; defaults to '.zkey.eu'
 */
static char *dns_suffix;

/**
 * FCFS suffix, suffix of FCFS-authority in DNS; defaults to 'fcfs.zkey.eu'.
 */
static char *fcfs_suffix;

/**
 * IP of DNS server
 */
static char *dns_ip;

/**
 * UDP Port we listen on for inbound DNS requests.
 */
static unsigned int listen_port = 53;

/**
 * Which GNS zone do we translate incoming DNS requests to?
 */
static struct GNUNET_CRYPTO_EcdsaPublicKey my_zone;

/**
 * '-z' option with the main zone to use.
 */
static char *gns_zone_str;

/**
 * Configuration to use.
 */
static const struct GNUNET_CONFIGURATION_Handle *cfg;

/**
 * Connection to identity service.
 */
static struct GNUNET_IDENTITY_Handle *identity;

/**
 * Request for our ego.
 */
static struct GNUNET_IDENTITY_Operation *id_op;


/**
 * Task run on shutdown.  Cleans up everything.
 *
 * @param cls unused
 * @param tc scheduler context
 */
static void
do_shutdown (void *cls,
	     const struct GNUNET_SCHEDULER_TaskContext *tc)
{
  if (NULL != t4)
    GNUNET_SCHEDULER_cancel (t4);
  if (NULL != t6)
    GNUNET_SCHEDULER_cancel (t6);
  if (NULL != listen_socket4)
  {
    GNUNET_NETWORK_socket_close (listen_socket4);
    listen_socket4 = NULL;
  }
  if (NULL != listen_socket6)
  {
    GNUNET_NETWORK_socket_close (listen_socket6);
    listen_socket6 = NULL;
  }
  if (NULL != id_op)
  {
    GNUNET_IDENTITY_cancel (id_op);
    id_op = NULL;
  }
  if (NULL != identity)
  {
    GNUNET_IDENTITY_disconnect (identity);
    identity = NULL;
  }
  if (NULL != gns)
  {
    GNUNET_GNS_disconnect (gns);
    gns = NULL;
  }
  if (NULL != dns_stub)
  {
    GNUNET_DNSSTUB_stop (dns_stub);
    dns_stub = NULL;
  }
}


/**
 * Send the response for the given request and clean up.
 *
 * @param request context for the request.
 */
static void
send_response (struct Request *request)
{
  char *buf;
  size_t size;

  if (GNUNET_SYSERR ==
      GNUNET_DNSPARSER_pack (request->packet,
			     UINT16_MAX /* is this not too much? */,
			     &buf,
			     &size))
    {
      GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
		  _("Failed to pack DNS response into UDP packet!\n"));
    }
  else
    {
      if (size !=
	  GNUNET_NETWORK_socket_sendto (request->lsock,
					buf, size,
					request->addr,
					request->addr_len))
	GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING, "sendto");
      GNUNET_free (buf);
    }
  GNUNET_SCHEDULER_cancel (request->timeout_task);
  GNUNET_DNSPARSER_free_packet (request->packet);
  GNUNET_free (request);
}


/**
 * Task run on timeout.  Cleans up request.
 *
 * @param cls 'struct Request' of the request to clean up
 * @param tc scheduler context
 */
static void
do_timeout (void *cls,
	    const struct GNUNET_SCHEDULER_TaskContext *tc)
{
  struct Request *request = cls;

  if (NULL != request->packet)
    GNUNET_DNSPARSER_free_packet (request->packet);
  if (NULL != request->lookup)
    GNUNET_GNS_lookup_cancel (request->lookup);
  if (NULL != request->dns_lookup)
    GNUNET_DNSSTUB_resolve_cancel (request->dns_lookup);
  GNUNET_free (request);
}


/**
 * Iterator called on obtained result for a DNS lookup
 *
 * @param cls closure
 * @param rs the request socket
 * @param dns the DNS udp payload
 * @param r size of the DNS payload
 */
static void
dns_result_processor (void *cls,
		      struct GNUNET_DNSSTUB_RequestSocket *rs,
		      const struct GNUNET_TUN_DnsHeader *dns,
		      size_t r)
{
  struct Request *request = cls;

  request->packet = GNUNET_DNSPARSER_parse ((char*)dns, r);
  send_response (request);
}


/**
 * Iterator called on obtained result for a GNS lookup.
 *
 * @param cls closure
 * @param rd_count number of records in @a rd
 * @param rd the records in reply
 */
static void
result_processor (void *cls,
		  uint32_t rd_count,
		  const struct GNUNET_GNSRECORD_Data *rd)
{
  struct Request *request = cls;
  struct GNUNET_DNSPARSER_Packet *packet;
  uint32_t i;
  struct GNUNET_DNSPARSER_Record rec;

  request->lookup = NULL;
  packet = request->packet;
  packet->flags.query_or_response = 1;
  packet->flags.return_code = GNUNET_TUN_DNS_RETURN_CODE_NO_ERROR;
  packet->flags.checking_disabled = 0;
  packet->flags.authenticated_data = 1;
  packet->flags.zero = 0;
  packet->flags.recursion_available = 1;
  packet->flags.message_truncated = 0;
  packet->flags.authoritative_answer = 0;
  //packet->flags.opcode = GNUNET_TUN_DNS_OPCODE_STATUS; // ???
  for (i=0;i<rd_count;i++)
    {
      // FIXME: do we need to hanlde #GNUNET_GNSRECORD_RF_SHADOW_RECORD
      // here? Or should we do this in libgnunetgns?
      rec.expiration_time.abs_value_us = rd[i].expiration_time;
      switch (rd[i].record_type)
	{
	case GNUNET_DNSPARSER_TYPE_A:
	  GNUNET_assert (sizeof (struct in_addr) == rd[i].data_size);
	  rec.name = GNUNET_strdup (packet->queries[0].name);
	  rec.dns_traffic_class = GNUNET_TUN_DNS_CLASS_INTERNET;
	  rec.type = GNUNET_DNSPARSER_TYPE_A;
	  rec.data.raw.data = GNUNET_new (struct in_addr);
	  memcpy (rec.data.raw.data,
		  rd[i].data,
		  rd[i].data_size);
	  rec.data.raw.data_len = sizeof (struct in_addr);
	  GNUNET_array_append (packet->answers,
			       packet->num_answers,
			       rec);
	  break;
	case GNUNET_DNSPARSER_TYPE_AAAA:
	  GNUNET_assert (sizeof (struct in6_addr) == rd[i].data_size);
	  rec.name = GNUNET_strdup (packet->queries[0].name);
	  rec.data.raw.data = GNUNET_new (struct in6_addr);
	  rec.dns_traffic_class = GNUNET_TUN_DNS_CLASS_INTERNET;
	  rec.type = GNUNET_DNSPARSER_TYPE_AAAA;
	  memcpy (rec.data.raw.data,
		  rd[i].data,
		  rd[i].data_size);
	  rec.data.raw.data_len = sizeof (struct in6_addr);
	  GNUNET_array_append (packet->answers,
			       packet->num_answers,
			       rec);
	  break;
	case GNUNET_DNSPARSER_TYPE_CNAME:
	  rec.name = GNUNET_strdup (packet->queries[0].name);
	  rec.data.hostname = strdup (rd[i].data);
	  rec.dns_traffic_class = GNUNET_TUN_DNS_CLASS_INTERNET;
	  rec.type = GNUNET_DNSPARSER_TYPE_CNAME;
	  memcpy (rec.data.hostname,
		  rd[i].data,
		  rd[i].data_size);
	  GNUNET_array_append (packet->answers,
			       packet->num_answers,
			       rec);
	  break;
	default:
	  /* skip */
	  break;
	}
    }
  send_response (request);
}


/**
 * Handle DNS request.
 *
 * @param lsock socket to use for sending the reply
 * @param addr address to use for sending the reply
 * @param addr_len number of bytes in @a addr
 * @param udp_msg DNS request payload
 * @param udp_msg_size number of bytes in @a udp_msg
 */
static void
handle_request (struct GNUNET_NETWORK_Handle *lsock,
		const void *addr,
		size_t addr_len,
		const char *udp_msg,
		size_t udp_msg_size)
{
  struct Request *request;
  struct GNUNET_DNSPARSER_Packet *packet;
  char *name;
  size_t name_len;
  int type;
  int use_gns;

  packet = GNUNET_DNSPARSER_parse (udp_msg, udp_msg_size);
  if (NULL == packet)
    {
      GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
		  _("Cannot parse DNS request from %s\n"),
		  GNUNET_a2s (addr, addr_len));
      return;
    }
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
	      "Received request for `%s' with flags %u, #answers %d, #auth %d, #additional %d\n",
	      packet->queries[0].name,
	      (unsigned int) packet->flags.query_or_response,
	      (int) packet->num_answers,
	      (int) packet->num_authority_records,
	      (int) packet->num_additional_records);
  if ( (0 != packet->flags.query_or_response) ||
       (0 != packet->num_answers) ||
       (0 != packet->num_authority_records))
    {
      GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
		  _("Received malformed DNS request from %s\n"),
		  GNUNET_a2s (addr, addr_len));
      GNUNET_DNSPARSER_free_packet (packet);
      return;
    }
  if ( (1 != packet->num_queries) )
    {
      GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
		  _("Received unsupported DNS request from %s\n"),
		  GNUNET_a2s (addr, addr_len));
      GNUNET_DNSPARSER_free_packet (packet);
      return;
    }
  request = GNUNET_malloc (sizeof (struct Request) + addr_len);
  request->lsock = lsock;
  request->packet = packet;
  request->addr = &request[1];
  request->addr_len = addr_len;
  memcpy (&request[1], addr, addr_len);
  request->timeout_task = GNUNET_SCHEDULER_add_delayed (TIMEOUT,
							&do_timeout,
							request);
  name = GNUNET_strdup (packet->queries[0].name);
  name_len = strlen (name);
  use_gns = GNUNET_NO;


  if ( (name_len > strlen (fcfs_suffix)) &&
       (0 == strcasecmp (fcfs_suffix,
			 &name[name_len - strlen (fcfs_suffix)])) )
  {
    /* replace ".fcfs.zkey.eu" with ".gnu" */
    strcpy (&name[name_len - strlen (fcfs_suffix)],
	    ".gnu");
    use_gns = GNUNET_YES;
  }
  else if ( (name_len > strlen (dns_suffix)) &&
            (0 == strcasecmp (dns_suffix,
                              &name[name_len - strlen (dns_suffix)])) )
  {
    /* replace ".zkey.eu" with ".zkey" */
    strcpy (&name[name_len - strlen (dns_suffix)],
	    ".zkey");
    use_gns = GNUNET_YES;
  } else if ( (name_len > strlen (".gnu")) &&
       (0 == strcasecmp (".gnu",
			 &name[name_len - strlen (".gnu")])) )
  {
    /* name is in GNS */
    use_gns = GNUNET_YES;
  }
  if (GNUNET_YES == use_gns)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
		"Calling GNS on `%s'\n",
		name);
    type = packet->queries[0].type;
    request->lookup = GNUNET_GNS_lookup (gns,
					 name,
					 &my_zone,
					 type,
					 GNUNET_NO,
					 NULL /* no shorten */,
					 &result_processor,
					 request);
  }
  else
  {
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
		"Using DNS resolver IP `%s' to resolve `%s'\n",
		dns_ip,
		name);
    GNUNET_DNSPARSER_free_packet (request->packet);
    request->packet = NULL;
    request->dns_lookup = GNUNET_DNSSTUB_resolve2 (dns_stub,
						   udp_msg,
						   udp_msg_size,
						   &dns_result_processor,
						   request);
  }
  GNUNET_free (name);
}


/**
 * Task to read IPv4 DNS packets.
 *
 * @param cls the 'listen_socket4'
 * @param tc scheduler context
 */
static void
read_dns4 (void *cls,
	   const struct GNUNET_SCHEDULER_TaskContext *tc)
{
  struct sockaddr_in v4;
  socklen_t addrlen;
  ssize_t size;

  GNUNET_assert (listen_socket4 == cls);
  t4 = GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL,
				      listen_socket4,
				      &read_dns4,
				      listen_socket4);
  if (0 == (GNUNET_SCHEDULER_REASON_READ_READY & tc->reason))
    return; /* shutdown? */
  size = GNUNET_NETWORK_socket_recvfrom_amount (listen_socket4);
  if (0 > size)
    {
      GNUNET_break (0);
      return; /* read error!? */
    }
  {
    char buf[size];

    addrlen = sizeof (v4);
    GNUNET_break (size ==
		  GNUNET_NETWORK_socket_recvfrom (listen_socket4,
						  buf,
						  size,
						  (struct sockaddr *) &v4,
						  &addrlen));
    handle_request (listen_socket4, &v4, addrlen,
		    buf, size);
  }
}


/**
 * Task to read IPv6 DNS packets.
 *
 * @param cls the 'listen_socket6'
 * @param tc scheduler context
 */
static void
read_dns6 (void *cls,
	   const struct GNUNET_SCHEDULER_TaskContext *tc)
{
  struct sockaddr_in6 v6;
  socklen_t addrlen;
  ssize_t size;

  GNUNET_assert (listen_socket6 == cls);
  t6 = GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL,
				      listen_socket6,
				      &read_dns6,
				      listen_socket6);
  if (0 == (GNUNET_SCHEDULER_REASON_READ_READY & tc->reason))
    return; /* shutdown? */
  size = GNUNET_NETWORK_socket_recvfrom_amount (listen_socket6);
  if (0 > size)
    {
      GNUNET_break (0);
      return; /* read error!? */
    }
  {
    char buf[size];

    addrlen = sizeof (v6);
    GNUNET_break (size ==
		  GNUNET_NETWORK_socket_recvfrom (listen_socket6,
						  buf,
						  size,
						  (struct sockaddr *) &v6,
						  &addrlen));
    handle_request (listen_socket6, &v6, addrlen,
		    buf, size);
  }
}


/**
 * Start DNS daemon.
 */
static void
run_dnsd ()
{
  if (NULL == dns_suffix)
    dns_suffix = DNS_SUFFIX;
  if (NULL == fcfs_suffix)
    fcfs_suffix = FCFS_SUFFIX;
  if (NULL == (gns = GNUNET_GNS_connect (cfg)))
    return;
  if (NULL == (dns_stub = GNUNET_DNSSTUB_start (dns_ip)))
  {
    GNUNET_GNS_disconnect (gns);
    gns = NULL;
    return;
  }
  listen_socket4 = GNUNET_NETWORK_socket_create (PF_INET,
						 SOCK_DGRAM,
						 IPPROTO_UDP);
  if (NULL != listen_socket4)
    {
      struct sockaddr_in v4;

      memset (&v4, 0, sizeof (v4));
      v4.sin_family = AF_INET;
#if HAVE_SOCKADDR_IN_SIN_LEN
      v4.sin_len = sizeof (v4);
#endif
      v4.sin_port = htons (listen_port);
      if (GNUNET_OK !=
	  GNUNET_NETWORK_socket_bind (listen_socket4,
				      (struct sockaddr *) &v4,
				      sizeof (v4)))
	{
	  GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR, "bind");
	  GNUNET_NETWORK_socket_close (listen_socket4);
	  listen_socket4 = NULL;
	}
    }
  listen_socket6 = GNUNET_NETWORK_socket_create (PF_INET6,
						SOCK_DGRAM,
						IPPROTO_UDP);
  if (NULL != listen_socket6)
    {
      struct sockaddr_in6 v6;

      memset (&v6, 0, sizeof (v6));
      v6.sin6_family = AF_INET6;
#if HAVE_SOCKADDR_IN_SIN_LEN
      v6.sin6_len = sizeof (v6);
#endif
      v6.sin6_port = htons (listen_port);
      if (GNUNET_OK !=
	  GNUNET_NETWORK_socket_bind (listen_socket6,
				      (struct sockaddr *) &v6,
				      sizeof (v6)))
	{
	  GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR, "bind");
	  GNUNET_NETWORK_socket_close (listen_socket6);
	  listen_socket6 = NULL;
	}
    }
  if ( (NULL == listen_socket4) &&
       (NULL == listen_socket6) )
    {
      GNUNET_GNS_disconnect (gns);
      gns = NULL;
      GNUNET_DNSSTUB_stop (dns_stub);
      dns_stub = NULL;
      return;
    }
  if (NULL != listen_socket4)
    t4 = GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL,
					listen_socket4,
					&read_dns4,
					listen_socket4);
  if (NULL != listen_socket6)
    t6 = GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL,
					listen_socket6,
					&read_dns6,
					listen_socket6);

}


/**
 * Method called to inform about the egos of this peer.
 *
 * When used with #GNUNET_IDENTITY_create or #GNUNET_IDENTITY_get,
 * this function is only called ONCE, and 'NULL' being passed in
 * @a ego does indicate an error (i.e. name is taken or no default
 * value is known).  If @a ego is non-NULL and if '*ctx'
 * is set in those callbacks, the value WILL be passed to a subsequent
 * call to the identity callback of #GNUNET_IDENTITY_connect (if
 * that one was not NULL).
 *
 * @param cls closure, NULL
 * @param ego ego handle
 * @param ctx context for application to store data for this ego
 *                 (during the lifetime of this process, initially NULL)
 * @param name name assigned by the user for this ego,
 *                   NULL if the user just deleted the ego and it
 *                   must thus no longer be used
 */
static void
identity_cb (void *cls,
	     struct GNUNET_IDENTITY_Ego *ego,
	     void **ctx,
	     const char *name)
{
  id_op = NULL;
  if (NULL == ego)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
		_("No ego configured for `dns2gns` subsystem\n"));
    return;
  }
  GNUNET_IDENTITY_ego_get_public_key (ego,
				      &my_zone);
  run_dnsd ();
}


/**
 * Main function that will be run.
 *
 * @param cls closure
 * @param args remaining command-line arguments
 * @param cfgfile name of the configuration file used (for saving, can be NULL!)
 * @param c configuration
 */
static void
run (void *cls, char *const *args, const char *cfgfile,
     const struct GNUNET_CONFIGURATION_Handle *c)
{
  cfg = c;

  if (NULL == dns_ip)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                _("No DNS server specified!\n"));
    return;
  }
  GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL,
				&do_shutdown, NULL);
  if (NULL == gns_zone_str)
    {
      identity = GNUNET_IDENTITY_connect (cfg,
					  NULL, NULL);
      id_op = GNUNET_IDENTITY_get (identity,
				   "dns2gns",
				   &identity_cb,
				   NULL);
      return;
    }
  if ( (NULL == gns_zone_str) ||
       (GNUNET_OK !=
	GNUNET_CRYPTO_ecdsa_public_key_from_string (gns_zone_str,
						  strlen (gns_zone_str),
						  &my_zone)) )
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
		_("No valid GNS zone specified!\n"));
    GNUNET_SCHEDULER_shutdown ();
    return;
  }
  run_dnsd ();
}


/**
 * The main function for the dns2gns daemon.
 *
 * @param argc number of arguments from the command line
 * @param argv command line arguments
 * @return 0 ok, 1 on error
 */
int
main (int argc,
      char *const *argv)
{
  static const struct GNUNET_GETOPT_CommandLineOption options[] = {
    {'d', "dns", "IP",
      gettext_noop ("IP of recursive DNS resolver to use (required)"), 1,
      &GNUNET_GETOPT_set_string, &dns_ip},
    {'f', "fcfs", "NAME",
      gettext_noop ("Authoritative FCFS suffix to use (optional); default: fcfs.zkey.eu"), 1,
      &GNUNET_GETOPT_set_string, &fcfs_suffix},
    {'s', "suffix", "SUFFIX",
      gettext_noop ("Authoritative DNS suffix to use (optional); default: zkey.eu"), 1,
      &GNUNET_GETOPT_set_string, &dns_suffix},
    {'p', "port", "UDPPORT",
      gettext_noop ("UDP port to listen on for inbound DNS requests; default: 53"), 1,
      &GNUNET_GETOPT_set_uint, &listen_port},
    {'z', "zone", "PUBLICKEY",
      gettext_noop ("Public key of the GNS zone to use (overrides default)"), 1,
      &GNUNET_GETOPT_set_string, &gns_zone_str},
    GNUNET_GETOPT_OPTION_END
  };
  int ret;

  if (GNUNET_OK != GNUNET_STRINGS_get_utf8_args (argc, argv,
						 &argc, &argv))
    return 2;
  GNUNET_log_setup ("gnunet-dns2gns", "WARNING", NULL);
  ret =
      (GNUNET_OK ==
       GNUNET_PROGRAM_run (argc, argv, "gnunet-dns2gns",
                           _("GNUnet DNS-to-GNS proxy (a DNS server)"),
			   options,
                           &run, NULL)) ? 0 : 1;
  GNUNET_free ((void*) argv);
  return ret;
}

/* end of gnunet-dns2gns.c */