src/gns/gnunet-service-gns_resolver.c

   1 /*
   2      This file is part of GNUnet.
   3      (C) 2011-2013 Christian Grothoff (and other contributing authors)
   4
   5      GNUnet is free software; you can redistribute it and/or modify
   6      it under the terms of the GNU General Public License as published
   7      by the Free Software Foundation; either version 3, or (at your
   8      option) any later version.
   9
  10      GNUnet is distributed in the hope that it will be useful, but
  11      WITHOUT ANY WARRANTY; without even the implied warranty of
  12      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13      General Public License for more details.
  14
  15      You should have received a copy of the GNU General Public License
  16      along with GNUnet; see the file COPYING.  If not, write to the
  17      Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18      Boston, MA 02111-1307, USA.
  19 */
  20
  21 /**
  22  * @file gns/gnunet-service-gns_resolver.c
  23  * @brief GNU Name System resolver logic
  24  * @author Martin Schanzenbach
  25  * @author Christian Grothoff
  26  *
  27  * TODO:
  28  * - GNS: handle special SRV names --- no delegation, direct lookup;
  29  *        can likely be done in 'resolver_lookup_get_next_label'. (#3003)
  30  * - revocation checks (use CORE-level broadcasts!), (#3004)
  31  * - DNAME support (#3005)
  32  */
  33 #include "platform.h"
  34 #include "gnunet_util_lib.h"
  35 #include "gnunet_dnsstub_lib.h"
  36 #include "gnunet_dht_service.h"
  37 #include "gnunet_namestore_service.h"
  38 #include "gnunet_dns_service.h"
  39 #include "gnunet_resolver_service.h"
  40 #include "gnunet_dnsparser_lib.h"
  41 #include "gnunet_gns_service.h"
  42 #include "gns.h"
  43 #include "gnunet-service-gns_resolver.h"
  44 #include "gnunet-service-gns_shorten.h"
  45 #include "gnunet_vpn_service.h"
  46
  47
  48 /**
  49  * Default DHT timeout for lookups.
  50  */
  51 #define DHT_LOOKUP_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 60)
  52
  53 /**
  54  * Default timeout for DNS lookups.
  55  */
  56 #define DNS_LOOKUP_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 5)
  57
  58 /**
  59  * Default timeout for VPN redirections.
  60  */
  61 #define VPN_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MINUTES, 30)
  62
  63 /**
  64  * DHT replication level
  65  */
  66 #define DHT_GNS_REPLICATION_LEVEL 5
  67
  68 /**
  69  * How deep do we allow recursions to go before we abort?
  70  */
  71 #define MAX_RECURSION 256
  72
  73
  74 /**
  75  * DLL to hold the authority chain we had to pass in the resolution
  76  * process.
  77  */
  78 struct AuthorityChain
  79 {
  80   /**
  81    * This is a DLL.
  82    */
  83   struct AuthorityChain *prev;
  84
  85   /**
  86    * This is a DLL.
  87    */
  88   struct AuthorityChain *next;
  89
  90   /**
  91    * Resolver handle this entry in the chain belongs to.
  92    */
  93   struct GNS_ResolverHandle *rh;
  94
  95   /**
  96    * label/name corresponding to the authority
  97    */
  98   char *label;
  99
 100   /**
 101    * #GNUNET_YES if the authority was a GNS authority,
 102    * #GNUNET_NO if the authority was a DNS authority.
 103    */
 104   int gns_authority;
 105
 106   /**
 107    * Information about the resolver authority for this label.
 108    */
 109   union
 110   {
 111
 112     /**
 113      * The zone of the GNS authority
 114      */
 115     struct GNUNET_CRYPTO_EccPublicSignKey gns_authority;
 116
 117     struct
 118     {
 119       /**
 120        * Domain of the DNS resolver that is the authority.
 121        * (appended to construct the DNS name to resolve;
 122        * this is NOT the DNS name of the DNS server!).
 123        */
 124       char name[GNUNET_DNSPARSER_MAX_NAME_LENGTH + 1];
 125
 126       /**
 127        * IP address of the DNS resolver that is authoritative.
 128        * (this implementation currently only supports one
 129        * IP at a time).
 130        */
 131       struct sockaddr_storage dns_ip;
 132
 133     } dns_authority;
 134
 135   } authority_info;
 136
 137 };
 138
 139
 140 /**
 141  * A result we got from DNS.
 142  */
 143 struct DnsResult
 144 {
 145
 146   /**
 147    * Kept in DLL.
 148    */
 149   struct DnsResult *next;
 150
 151   /**
 152    * Kept in DLL.
 153    */
 154   struct DnsResult *prev;
 155
 156   /**
 157    * Binary value stored in the DNS record (appended to this struct)
 158    */
 159   const void *data;
 160
 161   /**
 162    * Expiration time for the DNS record, 0 if we didn't
 163    * get anything useful (i.e. 'gethostbyname' was used).
 164    */
 165   uint64_t expiration_time;
 166
 167   /**
 168    * Number of bytes in 'data'.
 169    */
 170   size_t data_size;
 171
 172   /**
 173    * Type of the GNS/DNS record.
 174    */
 175   uint32_t record_type;
 176
 177 };
 178
 179
 180 /**
 181  * Closure for #vpn_allocation_cb.
 182  */
 183 struct VpnContext
 184 {
 185
 186   /**
 187    * Which resolution process are we processing.
 188    */
 189   struct GNS_ResolverHandle *rh;
 190
 191   /**
 192    * Handle to the VPN request that we were performing.
 193    */
 194   struct GNUNET_VPN_RedirectionRequest *vpn_request;
 195
 196   /**
 197    * Number of records serialized in 'rd_data'.
 198    */
 199   unsigned int rd_count;
 200
 201   /**
 202    * Serialized records.
 203    */
 204   char *rd_data;
 205
 206   /**
 207    * Number of bytes in 'rd_data'.
 208    */
 209   size_t rd_data_size;
 210 };
 211
 212
 213 /**
 214  * Handle to a currenty pending resolution.  On result (positive or
 215  * negative) the #GNS_ResultProcessor is called.
 216  */
 217 struct GNS_ResolverHandle
 218 {
 219
 220   /**
 221    * DLL
 222    */
 223   struct GNS_ResolverHandle *next;
 224
 225   /**
 226    * DLL
 227    */
 228   struct GNS_ResolverHandle *prev;
 229
 230   /**
 231    * The top-level GNS authoritative zone to query
 232    */
 233   struct GNUNET_CRYPTO_EccPublicSignKey authority_zone;
 234
 235   /**
 236    * called when resolution phase finishes
 237    */
 238   GNS_ResultProcessor proc;
 239
 240   /**
 241    * closure passed to proc
 242    */
 243   void* proc_cls;
 244
 245   /**
 246    * Handle for DHT lookups. should be NULL if no lookups are in progress
 247    */
 248   struct GNUNET_DHT_GetHandle *get_handle;
 249
 250   /**
 251    * Handle to a VPN request, NULL if none is active.
 252    */
 253   struct VpnContext *vpn_ctx;
 254
 255   /**
 256    * Socket for a DNS request, NULL if none is active.
 257    */
 258   struct GNUNET_DNSSTUB_RequestSocket *dns_request;
 259
 260   /**
 261    * Handle for standard DNS resolution, NULL if none is active.
 262    */
 263   struct GNUNET_RESOLVER_RequestHandle *std_resolve;
 264
 265   /**
 266    * Pending Namestore task
 267    */
 268   struct GNUNET_NAMESTORE_QueueEntry *namestore_qe;
 269
 270   /**
 271    * Heap node associated with this lookup.  Used to limit number of
 272    * concurrent requests.
 273    */
 274   struct GNUNET_CONTAINER_HeapNode *dht_heap_node;
 275
 276   /**
 277    * DLL to store the authority chain
 278    */
 279   struct AuthorityChain *ac_head;
 280
 281   /**
 282    * DLL to store the authority chain
 283    */
 284   struct AuthorityChain *ac_tail;
 285
 286   /**
 287    * Private key of the shorten zone, NULL to not shorten.
 288    */
 289   struct GNUNET_CRYPTO_EccPrivateKey *shorten_key;
 290
 291   /**
 292    * ID of a task associated with the resolution process.
 293    */
 294   GNUNET_SCHEDULER_TaskIdentifier task_id;
 295
 296   /**
 297    * The name to resolve
 298    */
 299   char *name;
 300
 301   /**
 302    * DLL of results we got from DNS.
 303    */
 304   struct DnsResult *dns_result_head;
 305
 306   /**
 307    * DLL of results we got from DNS.
 308    */
 309   struct DnsResult *dns_result_tail;
 310
 311   /**
 312    * Current offset in 'name' where we are resolving.
 313    */
 314   size_t name_resolution_pos;
 315
 316   /**
 317    * Use only cache
 318    */
 319   int only_cached;
 320
 321   /**
 322    * Desired type for the resolution.
 323    */
 324   int record_type;
 325
 326   /**
 327    * We increment the loop limiter for each step in a recursive
 328    * resolution.  If it passes our threshold (i.e. due to
 329    * self-recursion in the resolution, i.e CNAME fun), we stop.
 330    */
 331   unsigned int loop_limiter;
 332
 333 };
 334
 335
 336 /**
 337  * Our handle to the namestore service
 338  */
 339 static struct GNUNET_NAMESTORE_Handle *namestore_handle;
 340
 341 /**
 342  * Our handle to the vpn service
 343  */
 344 static struct GNUNET_VPN_Handle *vpn_handle;
 345
 346 /**
 347  * Resolver handle to the dht
 348  */
 349 static struct GNUNET_DHT_Handle *dht_handle;
 350
 351 /**
 352  * Handle to perform DNS lookups.
 353  */
 354 static struct GNUNET_DNSSTUB_Context *dns_handle;
 355
 356 /**
 357  * Heap for limiting parallel DHT lookups
 358  */
 359 static struct GNUNET_CONTAINER_Heap *dht_lookup_heap;
 360
 361 /**
 362  * Maximum amount of parallel queries to the DHT
 363  */
 364 static unsigned long long max_allowed_background_queries;
 365
 366 /**
 367  * Head of resolver lookup list
 368  */
 369 static struct GNS_ResolverHandle *rlh_head;
 370
 371 /**
 372  * Tail of resolver lookup list
 373  */
 374 static struct GNS_ResolverHandle *rlh_tail;
 375
 376 /**
 377  * Global configuration.
 378  */
 379 static const struct GNUNET_CONFIGURATION_Handle *cfg;
 380
 381
 382 /**
 383  * Check if name is in srv format (_x._y.xxx)
 384  *
 385  * @param name
 386  * @return #GNUNET_YES if true
 387  */
 388 static int
 389 is_srv (const char *name)
 390 {
 391   char *ndup;
 392   int ret;
 393
 394   if (*name != '_')
 395     return GNUNET_NO;
 396   if (NULL == strstr (name, "._"))
 397     return GNUNET_NO;
 398   ret = GNUNET_YES;
 399   ndup = GNUNET_strdup (name);
 400   strtok (ndup, ".");
 401   if (NULL == strtok (NULL, "."))
 402     ret = GNUNET_NO;
 403   if (NULL == strtok (NULL, "."))
 404     ret = GNUNET_NO;
 405   if (NULL != strtok (NULL, "."))
 406     ret = GNUNET_NO;
 407   GNUNET_free (ndup);
 408   return ret;
 409 }
 410
 411
 412 /**
 413  * Determine if this name is canonical (is a legal name in a zone, without delegation);
 414  * note that we do not test that the name does not contain illegal characters, we only
 415  * test for delegation.  Note that service records (i.e. _foo._srv) are canonical names
 416  * even though they consist of multiple labels.
 417  *
 418  * Examples:
 419  * a.b.gnu  = not canonical
 420  * a         = canonical
 421  * _foo._srv = canonical
 422  * _f.bar    = not canonical
 423  *
 424  * @param name the name to test
 425  * @return #GNUNET_YES if canonical
 426  */
 427 static int
 428 is_canonical (const char *name)
 429 {
 430   const char *pos;
 431   const char *dot;
 432
 433   if (NULL == strchr (name, '.'))
 434     return GNUNET_YES;
 435   if ('_' != name[0])
 436     return GNUNET_NO;
 437   pos = &name[1];
 438   while (NULL != (dot = strchr (pos, '.')))
 439     if ('_' != dot[1])
 440       return GNUNET_NO;
 441     else
 442       pos = dot + 1;
 443   return GNUNET_YES;
 444 }
 445
 446 /* ************************** Resolution **************************** */
 447
 448 /**
 449  * Exands a name ending in .+ with the zone of origin.
 450  *
 451  * @param rh resolution context
 452  * @param name name to modify (to be free'd or returned)
 453  * @return updated name
 454  */
 455 static char *
 456 translate_dot_plus (struct GNS_ResolverHandle *rh,
 457                     char *name)
 458 {
 459   char *ret;
 460   size_t s_len = strlen (name);
 461
 462   if (0 != strcmp (&name[s_len - 2],
 463                    ".+"))
 464     return name; /* did not end in ".+" */
 465   GNUNET_assert (GNUNET_YES == rh->ac_tail->gns_authority);
 466   GNUNET_asprintf (&ret,
 467                    "%.*s.%s",
 468                    (int) (s_len - 2),
 469                    name,
 470                    GNUNET_NAMESTORE_pkey_to_zkey (&rh->ac_tail->authority_info.gns_authority));
 471   GNUNET_free (name);
 472   return ret;
 473 }
 474
 475
 476 /**
 477  * Task scheduled to asynchronously fail a resolution.
 478  *
 479  * @param cls the 'struct GNS_ResolverHandle' of the resolution to fail
 480  * @param tc task context
 481  */
 482 static void
 483 fail_resolution (void *cls,
 484                  const struct GNUNET_SCHEDULER_TaskContext *tc)
 485 {
 486   struct GNS_ResolverHandle *rh = cls;
 487
 488   rh->task_id = GNUNET_SCHEDULER_NO_TASK;
 489   rh->proc (rh->proc_cls, 0, NULL);
 490   GNS_resolver_lookup_cancel (rh);
 491 }
 492
 493
 494 #if (defined WINDOWS) || (defined DARWIN)
 495 /* Don't have this on W32, here's a naive implementation
 496  * Was somehow removed on OS X ...  */
 497 void *
 498 memrchr (const void *s,
 499          int c,
 500          size_t n)
 501 {
 502   unsigned char *ucs = s;
 503   ssize_t i;
 504
 505   for (i = n - 1; i >= 0; i--)
 506     if (c == (int) ucs[i])
 507       return (void *) &ucs[i];
 508   return NULL;
 509 }
 510 #endif
 511
 512
 513 /**
 514  * Get the next, rightmost label from the name that we are trying to resolve,
 515  * and update the resolution position accordingly.
 516  *
 517  * @param rh handle to the resolution operation to get the next label from
 518  * @return NULL if there are no more labels
 519  */
 520 static char *
 521 resolver_lookup_get_next_label (struct GNS_ResolverHandle *rh)
 522 {
 523   const char *rp;
 524   const char *dot;
 525   size_t len;
 526
 527   if (0 == rh->name_resolution_pos)
 528     return NULL;
 529   dot = memrchr (rh->name, (int) '.', rh->name_resolution_pos);
 530   if (NULL == dot)
 531   {
 532     /* done, this was the last one */
 533     len = rh->name_resolution_pos;
 534     rp = rh->name;
 535     rh->name_resolution_pos = 0;
 536   }
 537   else
 538   {
 539     /* advance by one label */
 540     len = rh->name_resolution_pos - (dot - rh->name) - 1;
 541     rp = dot + 1;
 542     rh->name_resolution_pos = dot - rh->name;
 543   }
 544   return GNUNET_strndup (rp, len);
 545 }
 546
 547
 548 /**
 549  * Gives the cummulative result obtained to the callback and clean up the request.
 550  *
 551  * @param rh resolution process that has culminated in a result
 552  */
 553 static void
 554 transmit_lookup_dns_result (struct GNS_ResolverHandle *rh)
 555 {
 556   struct DnsResult *pos;
 557   unsigned int n;
 558   unsigned int i;
 559
 560   n = 0;
 561   for (pos = rh->dns_result_head; NULL != pos; pos = pos->next)
 562     n++;
 563   {
 564     struct GNUNET_NAMESTORE_RecordData rd[n];
 565
 566     i = 0;
 567     for (pos = rh->dns_result_head; NULL != pos; pos = pos->next)
 568     {
 569       rd[i].data = pos->data;
 570       rd[i].data_size = pos->data_size;
 571       rd[i].record_type = pos->record_type;
 572       if (0 == pos->expiration_time)
 573       {
 574         rd[i].flags = GNUNET_NAMESTORE_RF_RELATIVE_EXPIRATION;
 575         rd[i].expiration_time = 0;
 576       }
 577       else
 578       {
 579         rd[i].flags = GNUNET_NAMESTORE_RF_NONE;
 580         rd[i].expiration_time = pos->expiration_time;
 581       }
 582       i++;
 583     }
 584     GNUNET_assert (i == n);
 585     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 586                 "Transmitting standard DNS result with %u records\n",
 587                 n);
 588     rh->proc (rh->proc_cls,
 589               n,
 590               rd);
 591   }
 592   GNS_resolver_lookup_cancel (rh);
 593 }
 594
 595
 596 /**
 597  * Add a result from DNS to the records to be returned to the application.
 598  *
 599  * @param rh resolution request to extend with a result
 600  * @param expiration_time expiration time for the answer
 601  * @param record_type DNS record type of the answer
 602  * @param data_size number of bytes in @a data
 603  * @param data binary data to return in DNS record
 604  */
 605 static void
 606 add_dns_result (struct GNS_ResolverHandle *rh,
 607                 uint64_t expiration_time,
 608                 uint32_t record_type,
 609                 size_t data_size,
 610                 const void *data)
 611 {
 612   struct DnsResult *res;
 613
 614   res = GNUNET_malloc (sizeof (struct DnsResult) + data_size);
 615   res->expiration_time = expiration_time;
 616   res->data_size = data_size;
 617   res->record_type = record_type;
 618   res->data = &res[1];
 619   memcpy (&res[1], data, data_size);
 620   GNUNET_CONTAINER_DLL_insert (rh->dns_result_head,
 621                                rh->dns_result_tail,
 622                                res);
 623 }
 624
 625
 626 /**
 627  * We had to do a DNS lookup.  Convert the result (if any) and return
 628  * it.
 629  *
 630  * @param cls closure with the 'struct GNS_ResolverHandle'
 631  * @param addr one of the addresses of the host, NULL for the last address
 632  * @param addrlen length of the address
 633  */
 634 static void
 635 handle_dns_result (void *cls,
 636                    const struct sockaddr *addr,
 637                    socklen_t addrlen)
 638 {
 639   struct GNS_ResolverHandle *rh = cls;
 640   const struct sockaddr_in *sa4;
 641   const struct sockaddr_in6 *sa6;
 642
 643   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 644               "Received %u bytes of DNS IP data\n",
 645               addrlen);
 646   if (NULL == addr)
 647   {
 648     rh->std_resolve = NULL;
 649     transmit_lookup_dns_result (rh);
 650     return;
 651   }
 652   switch (addr->sa_family)
 653   {
 654   case AF_INET:
 655     sa4 = (const struct sockaddr_in *) addr;
 656     add_dns_result (rh,
 657                     0 /* expiration time is unknown */,
 658                     GNUNET_DNSPARSER_TYPE_A,
 659                     sizeof (struct in_addr),
 660                     &sa4->sin_addr);
 661     break;
 662   case AF_INET6:
 663     sa6 = (const struct sockaddr_in6 *) addr;
 664     add_dns_result (rh,
 665                     0 /* expiration time is unknown */,
 666                     GNUNET_DNSPARSER_TYPE_AAAA,
 667                     sizeof (struct in6_addr),
 668                     &sa6->sin6_addr);
 669     break;
 670   default:
 671     GNUNET_break (0);
 672     break;
 673   }
 674 }
 675
 676
 677 /**
 678  * Task scheduled to continue with the resolution process.
 679  *
 680  * @param cls the 'struct GNS_ResolverHandle' of the resolution
 681  * @param tc task context
 682  */
 683 static void
 684 recursive_resolution (void *cls,
 685                       const struct GNUNET_SCHEDULER_TaskContext *tc);
 686
 687
 688 /**
 689  * Begin the resolution process from 'name', starting with
 690  * the identification of the zone specified by 'name'.
 691  *
 692  * @param rh resolution to perform
 693  */
 694 static void
 695 start_resolver_lookup (struct GNS_ResolverHandle *rh);
 696
 697
 698 /**
 699  * Function called with the result of a DNS resolution.
 700  *
 701  * @param cls the request handle of the resolution that
 702  *        we were attempting to make
 703  * @param rs socket that received the response
 704  * @param dns dns response, never NULL
 705  * @param dns_len number of bytes in @a dns
 706  */
 707 static void
 708 dns_result_parser (void *cls,
 709                    struct GNUNET_DNSSTUB_RequestSocket *rs,
 710                    const struct GNUNET_TUN_DnsHeader *dns,
 711                    size_t dns_len)
 712 {
 713   struct GNS_ResolverHandle *rh = cls;
 714   struct GNUNET_DNSPARSER_Packet *p;
 715   const struct GNUNET_DNSPARSER_Record *rec;
 716   unsigned int rd_count;
 717   unsigned int i;
 718
 719   rh->dns_request = NULL;
 720   GNUNET_SCHEDULER_cancel (rh->task_id);
 721   rh->task_id = GNUNET_SCHEDULER_NO_TASK;
 722   p = GNUNET_DNSPARSER_parse ((const char *) dns,
 723                               dns_len);
 724   if (NULL == p)
 725   {
 726     GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
 727                 _("Failed to parse DNS response\n"));
 728     rh->proc (rh->proc_cls, 0, NULL);
 729     GNS_resolver_lookup_cancel (rh);
 730     return;
 731   }
 732   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 733               "Received DNS response for `%s' with %u answers\n",
 734               rh->ac_tail->label,
 735               (unsigned int) p->num_answers);
 736   if ( (p->num_answers > 0) &&
 737        (GNUNET_DNSPARSER_TYPE_CNAME == p->answers[0].type) &&
 738        (GNUNET_DNSPARSER_TYPE_CNAME != rh->record_type) )
 739     {
 740       GNUNET_free (rh->name);
 741       rh->name = GNUNET_strdup (p->answers[0].data.hostname);
 742       start_resolver_lookup (rh);
 743       GNUNET_DNSPARSER_free_packet (p);
 744       return;
 745     }
 746   /* FIXME: add DNAME support */
 747
 748   /* convert from (parsed) DNS to (binary) GNS format! */
 749   rd_count = p->num_answers + p->num_authority_records + p->num_additional_records;
 750   {
 751     struct GNUNET_NAMESTORE_RecordData rd[rd_count];
 752     unsigned int skip;
 753     char buf[UINT16_MAX];
 754     size_t buf_off;
 755
 756     buf_off = 0;
 757     skip = 0;
 758     memset (rd, 0, sizeof (rd));
 759     for (i=0;i<rd_count;i++)
 760     {
 761       if (i < p->num_answers)
 762         rec = &p->answers[i];
 763       else if (i < p->num_answers + p->num_authority_records)
 764         rec = &p->authority_records[i - p->num_answers];
 765       else
 766         rec = &p->authority_records[i - p->num_answers - p->num_authority_records];
 767       /* As we copied the full DNS name to 'rh->ac_tail->label', this
 768          should be the correct check to see if this record is actually
 769          a record for our label... */
 770       if (0 != strcmp (rec->name,
 771                        rh->ac_tail->label))
 772       {
 773         GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 774                     "Dropping record `%s', does not match desired name `%s'\n",
 775                     rec->name,
 776                     rh->ac_tail->label);
 777         skip++;
 778         continue;
 779       }
 780       rd[i - skip].record_type = rec->type;
 781       rd[i - skip].expiration_time = rec->expiration_time.abs_value_us;
 782       switch (rec->type)
 783       {
 784       case GNUNET_DNSPARSER_TYPE_A:
 785         if (rec->data.raw.data_len != sizeof (struct in_addr))
 786         {
 787           GNUNET_break_op (0);
 788           skip++;
 789           continue;
 790         }
 791         rd[i - skip].data_size = rec->data.raw.data_len;
 792         rd[i - skip].data = rec->data.raw.data;
 793         break;
 794       case GNUNET_DNSPARSER_TYPE_AAAA:
 795         if (rec->data.raw.data_len != sizeof (struct in6_addr))
 796         {
 797           GNUNET_break_op (0);
 798           skip++;
 799           continue;
 800         }
 801         rd[i - skip].data_size = rec->data.raw.data_len;
 802         rd[i - skip].data = rec->data.raw.data;
 803         break;
 804       case GNUNET_DNSPARSER_TYPE_CNAME:
 805       case GNUNET_DNSPARSER_TYPE_PTR:
 806       case GNUNET_DNSPARSER_TYPE_NS:
 807         if (GNUNET_OK !=
 808             GNUNET_DNSPARSER_builder_add_name (buf,
 809                                                sizeof (buf),
 810                                                &buf_off,
 811                                                rec->data.hostname))
 812         {
 813           GNUNET_break (0);
 814           skip++;
 815           continue;
 816         }
 817         break;
 818       case GNUNET_DNSPARSER_TYPE_SOA:
 819         if (GNUNET_OK !=
 820             GNUNET_DNSPARSER_builder_add_soa (buf,
 821                                                sizeof (buf),
 822                                                &buf_off,
 823                                                rec->data.soa))
 824         {
 825           GNUNET_break (0);
 826           skip++;
 827           continue;
 828         }
 829         break;
 830       case GNUNET_DNSPARSER_TYPE_MX:
 831         if (GNUNET_OK !=
 832             GNUNET_DNSPARSER_builder_add_mx (buf,
 833                                              sizeof (buf),
 834                                              &buf_off,
 835                                              rec->data.mx))
 836         {
 837           GNUNET_break (0);
 838           skip++;
 839           continue;
 840         }
 841         break;
 842       case GNUNET_DNSPARSER_TYPE_SRV:
 843         if (GNUNET_OK !=
 844             GNUNET_DNSPARSER_builder_add_srv (buf,
 845                                               sizeof (buf),
 846                                               &buf_off,
 847                                               rec->data.srv))
 848         {
 849           GNUNET_break (0);
 850           skip++;
 851           continue;
 852         }
 853         break;
 854       default:
 855         GNUNET_log (GNUNET_ERROR_TYPE_INFO,
 856                     _("Skipping record of unsupported type %d\n"),
 857                     rec->type);
 858         skip++;
 859         continue;
 860       }
 861     }
 862     rh->proc (rh->proc_cls, rd_count - skip, rd);
 863     GNS_resolver_lookup_cancel (rh);
 864   }
 865   GNUNET_DNSPARSER_free_packet (p);
 866 }
 867
 868
 869 /**
 870  * Perform recursive DNS resolution.  Asks the given DNS resolver to
 871  * resolve "rh->dns_name", possibly recursively proceeding following
 872  * NS delegations, CNAMES, etc., until 'rh->loop_limiter' bounds us or
 873  * we find the answer.
 874  *
 875  * @param rh resolution information
 876  */
 877 static void
 878 recursive_dns_resolution (struct GNS_ResolverHandle *rh)
 879 {
 880   struct AuthorityChain *ac;
 881   socklen_t sa_len;
 882   struct GNUNET_DNSPARSER_Query *query;
 883   struct GNUNET_DNSPARSER_Packet *p;
 884   char *dns_request;
 885   size_t dns_request_length;
 886
 887   ac = rh->ac_tail;
 888   GNUNET_assert (NULL != ac);
 889   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 890               "Starting DNS lookup for `%s'\n",
 891               ac->label);
 892   GNUNET_assert (GNUNET_NO == ac->gns_authority);
 893   switch (((const struct sockaddr *) &ac->authority_info.dns_authority.dns_ip)->sa_family)
 894   {
 895   case AF_INET:
 896     sa_len = sizeof (struct sockaddr_in);
 897     break;
 898   case AF_INET6:
 899     sa_len = sizeof (struct sockaddr_in6);
 900     break;
 901   default:
 902     GNUNET_break (0);
 903     rh->proc (rh->proc_cls, 0, NULL);
 904     GNS_resolver_lookup_cancel (rh);
 905     return;
 906   }
 907   query = GNUNET_new (struct GNUNET_DNSPARSER_Query);
 908   query->name = GNUNET_strdup (ac->label);
 909   query->type = rh->record_type;
 910   query->class = GNUNET_TUN_DNS_CLASS_INTERNET;
 911   p = GNUNET_new (struct GNUNET_DNSPARSER_Packet);
 912   p->queries = query;
 913   p->num_queries = 1;
 914   p->id = (uint16_t) GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE,
 915                                                UINT16_MAX);
 916   p->flags.opcode = GNUNET_TUN_DNS_OPCODE_QUERY;
 917   p->flags.recursion_desired = 1;
 918   if (GNUNET_OK !=
 919       GNUNET_DNSPARSER_pack (p, 1024, &dns_request, &dns_request_length))
 920   {
 921     GNUNET_break (0);
 922     rh->proc (rh->proc_cls, 0, NULL);
 923     GNS_resolver_lookup_cancel (rh);
 924   }
 925   else
 926   {
 927     rh->dns_request = GNUNET_DNSSTUB_resolve (dns_handle,
 928                                               (const struct sockaddr *) &ac->authority_info.dns_authority.dns_ip,
 929                                               sa_len,
 930                                               dns_request,
 931                                               dns_request_length,
 932                                               &dns_result_parser,
 933                                               rh);
 934     rh->task_id = GNUNET_SCHEDULER_add_delayed (DNS_LOOKUP_TIMEOUT,
 935                                                 &fail_resolution,
 936                                                 rh);
 937   }
 938   GNUNET_free (dns_request);
 939   GNUNET_DNSPARSER_free_packet (p);
 940 }
 941
 942
 943 /**
 944  * We encountered a CNAME record during our resolution.
 945  * Merge it into our chain.
 946  *
 947  * @param rh resolution we are performing
 948  * @param cname value of the cname record we got for the current
 949  *        authority chain tail
 950  */
 951 static void
 952 handle_gns_cname_result (struct GNS_ResolverHandle *rh,
 953                          const char *cname)
 954 {
 955   size_t nlen;
 956   char *res;
 957   struct AuthorityChain *ac;
 958
 959   nlen = strlen (cname);
 960   if ( (nlen > 2) &&
 961        (0 == strcmp (".+",
 962                      &cname[nlen - 2])) )
 963   {
 964     /* CNAME resolution continues relative to current domain */
 965     if (0 == rh->name_resolution_pos)
 966     {
 967       res = GNUNET_strndup (cname, nlen - 2);
 968       rh->name_resolution_pos = nlen - 2;
 969     }
 970     else
 971     {
 972       GNUNET_asprintf (&res,
 973                        "%.*s.%.*s",
 974                        (int) rh->name_resolution_pos,
 975                        rh->name,
 976                        (int) (nlen - 2),
 977                        cname);
 978       rh->name_resolution_pos = strlen (res);
 979     }
 980     GNUNET_free (rh->name);
 981     rh->name = res;
 982     ac = GNUNET_new (struct AuthorityChain);
 983     ac->rh = rh;
 984     ac->gns_authority = GNUNET_YES;
 985     ac->authority_info.gns_authority = rh->ac_tail->authority_info.gns_authority;
 986     ac->label = resolver_lookup_get_next_label (rh);
 987     /* tigger shortening */
 988     if (NULL != rh->shorten_key)
 989       GNS_shorten_start (rh->ac_tail->label,
 990                          &ac->authority_info.gns_authority,
 991                          rh->shorten_key);
 992     /* add AC to tail */
 993     GNUNET_CONTAINER_DLL_insert_tail (rh->ac_head,
 994                                       rh->ac_tail,
 995                                       ac);
 996     rh->task_id = GNUNET_SCHEDULER_add_now (&recursive_resolution,
 997                                             rh);
 998     return;
 999   }
1000   /* name is absolute, start from the beginning */
1001   GNUNET_free (rh->name);
1002   rh->name = GNUNET_strdup (cname);
1003   start_resolver_lookup (rh);
1004 }
1005
1006
1007 /**
1008  * Process a records that were decrypted from a block.
1009  *
1010  * @param cls closure with the 'struct GNS_ResolverHandle'
1011  * @param rd_count number of entries in @a rd array
1012  * @param rd array of records with data to store
1013  */
1014 static void
1015 handle_gns_resolution_result (void *cls,
1016                               unsigned int rd_count,
1017                               const struct GNUNET_NAMESTORE_RecordData *rd);
1018
1019
1020 /**
1021  * Callback invoked from the VPN service once a redirection is
1022  * available.  Provides the IP address that can now be used to
1023  * reach the requested destination.  Replaces the "VPN" record
1024  * with the respective A/AAAA record and continues processing.
1025  *
1026  * @param cls closure
1027  * @param af address family, AF_INET or AF_INET6; AF_UNSPEC on error;
1028  *                will match 'result_af' from the request
1029  * @param address IP address (struct in_addr or struct in_addr6, depending on 'af')
1030  *                that the VPN allocated for the redirection;
1031  *                traffic to this IP will now be redirected to the
1032  *                specified target peer; NULL on error
1033  */
1034 static void
1035 vpn_allocation_cb (void *cls,
1036                    int af,
1037                    const void *address)
1038 {
1039   struct VpnContext *vpn_ctx = cls;
1040   struct GNS_ResolverHandle *rh = vpn_ctx->rh;
1041   struct GNUNET_NAMESTORE_RecordData rd[vpn_ctx->rd_count];
1042   unsigned int i;
1043
1044   vpn_ctx->vpn_request = NULL;
1045   rh->vpn_ctx = NULL;
1046   GNUNET_assert (GNUNET_OK ==
1047                  GNUNET_NAMESTORE_records_deserialize (vpn_ctx->rd_data_size,
1048                                                        vpn_ctx->rd_data,
1049                                                        vpn_ctx->rd_count,
1050                                                        rd));
1051   for (i=0;i<vpn_ctx->rd_count;i++)
1052   {
1053     if (GNUNET_NAMESTORE_TYPE_VPN == rd[i].record_type)
1054     {
1055       switch (af)
1056       {
1057       case AF_INET:
1058         rd[i].record_type = GNUNET_DNSPARSER_TYPE_A;
1059         rd[i].data_size = sizeof (struct in_addr);
1060         rd[i].expiration_time = GNUNET_TIME_relative_to_absolute (VPN_TIMEOUT).abs_value_us;
1061         rd[i].flags = 0;
1062         rd[i].data = address;
1063         break;
1064       case AF_INET6:
1065         rd[i].record_type = GNUNET_DNSPARSER_TYPE_AAAA;
1066         rd[i].expiration_time = GNUNET_TIME_relative_to_absolute (VPN_TIMEOUT).abs_value_us;
1067         rd[i].flags = 0;
1068         rd[i].data = address;
1069         rd[i].data_size = sizeof (struct in6_addr);
1070         break;
1071       default:
1072         GNUNET_assert (0);
1073       }
1074       break;
1075     }
1076   }
1077   GNUNET_assert (i < vpn_ctx->rd_count);
1078   handle_gns_resolution_result (rh,
1079                                 vpn_ctx->rd_count,
1080                                 rd);
1081   GNUNET_free (vpn_ctx->rd_data);
1082   GNUNET_free (vpn_ctx);
1083 }
1084
1085
1086 /**
1087  * Process a records that were decrypted from a block.
1088  *
1089  * @param cls closure with the `struct GNS_ResolverHandle`
1090  * @param rd_count number of entries in @a rd array
1091  * @param rd array of records with data to store
1092  */
1093 static void
1094 handle_gns_resolution_result (void *cls,
1095                               unsigned int rd_count,
1096                               const struct GNUNET_NAMESTORE_RecordData *rd)
1097 {
1098   struct GNS_ResolverHandle *rh = cls;
1099   struct AuthorityChain *ac;
1100   unsigned int i;
1101   unsigned int j;
1102   struct sockaddr *sa;
1103   struct sockaddr_in v4;
1104   struct sockaddr_in6 v6;
1105   size_t sa_len;
1106   char *cname;
1107   struct VpnContext *vpn_ctx;
1108   const struct GNUNET_TUN_GnsVpnRecord *vpn;
1109   const char *vname;
1110   struct GNUNET_HashCode vhash;
1111   int af;
1112   char scratch[UINT16_MAX];
1113   size_t scratch_off;
1114   size_t scratch_start;
1115   size_t off;
1116   struct GNUNET_NAMESTORE_RecordData rd_new[rd_count];
1117   unsigned int rd_off;
1118
1119   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1120               "Resolution succeeded for `%s' in zone %s, got %u records\n",
1121               rh->ac_tail->label,
1122               GNUNET_NAMESTORE_z2s (&rh->ac_tail->authority_info.gns_authority),
1123               rd_count);
1124   if (0 == rh->name_resolution_pos)
1125   {
1126     /* top-level match, are we done yet? */
1127     if ( (rd_count > 0) &&
1128          (GNUNET_DNSPARSER_TYPE_CNAME == rd[0].record_type) &&
1129          (GNUNET_DNSPARSER_TYPE_CNAME != rh->record_type) )
1130     {
1131       off = 0;
1132       cname = GNUNET_DNSPARSER_parse_name (rd[0].data,
1133                                            rd[0].data_size,
1134                                            &off);
1135       if ( (NULL == cname) ||
1136            (off != rd[0].data_size) )
1137       {
1138         GNUNET_break_op (0);
1139         rh->proc (rh->proc_cls, 0, NULL);
1140         GNS_resolver_lookup_cancel (rh);
1141         return;
1142       }
1143       handle_gns_cname_result (rh,
1144                                cname);
1145       GNUNET_free (cname);
1146       return;
1147     }
1148     /* If A/AAAA was requested, but we got a VPN
1149        record, we convert it to A/AAAA using GNUnet VPN */
1150     if ( (GNUNET_DNSPARSER_TYPE_A == rh->record_type) ||
1151          (GNUNET_DNSPARSER_TYPE_AAAA == rh->record_type) )
1152     {
1153       for (i=0;i<rd_count;i++)
1154       {
1155         if (GNUNET_NAMESTORE_TYPE_VPN == rd[i].record_type)
1156         {
1157           af = (GNUNET_DNSPARSER_TYPE_A == rh->record_type) ? AF_INET : AF_INET6;
1158           if (sizeof (struct GNUNET_TUN_GnsVpnRecord) <
1159               rd[i].data_size)
1160           {
1161             GNUNET_break_op (0);
1162             rh->proc (rh->proc_cls, 0, NULL);
1163             GNS_resolver_lookup_cancel (rh);
1164             return;
1165           }
1166           vpn = (const struct GNUNET_TUN_GnsVpnRecord *) rd[i].data;
1167           vname = (const char *) &vpn[1];
1168           if ('\0' != vname[rd[i].data_size - 1 - sizeof (struct GNUNET_TUN_GnsVpnRecord)])
1169           {
1170             GNUNET_break_op (0);
1171             rh->proc (rh->proc_cls, 0, NULL);
1172             GNS_resolver_lookup_cancel (rh);
1173             return;
1174           }
1175           GNUNET_CRYPTO_hash (vname,
1176                               strlen (vname), // FIXME: +1?
1177                               &vhash);
1178           vpn_ctx = GNUNET_new (struct VpnContext);
1179           rh->vpn_ctx = vpn_ctx;
1180           vpn_ctx->rh = rh;
1181           vpn_ctx->rd_data_size = GNUNET_NAMESTORE_records_get_size (rd_count,
1182                                                                      rd);
1183           vpn_ctx->rd_data = GNUNET_malloc (vpn_ctx->rd_data_size);
1184           (void) GNUNET_NAMESTORE_records_serialize (rd_count,
1185                                                      rd,
1186                                                      vpn_ctx->rd_data_size,
1187                                                      vpn_ctx->rd_data);
1188           vpn_ctx->vpn_request = GNUNET_VPN_redirect_to_peer (vpn_handle,
1189                                                               af,
1190                                                               ntohs (vpn->proto),
1191                                                               &vpn->peer,
1192                                                               &vhash,
1193                                                               GNUNET_TIME_relative_to_absolute (VPN_TIMEOUT),
1194                                                               &vpn_allocation_cb,
1195                                                               rh);
1196           return;
1197         }
1198       }
1199     }
1200     /* convert relative names in record values to absolute names,
1201        using 'scratch' array for memory allocations */
1202     scratch_off = 0;
1203     rd_off = 0;
1204     for (i=0;i<rd_count;i++)
1205     {
1206       rd_new[rd_off] = rd[i];
1207       /* Check if the embedded name(s) end in "+", and if so,
1208          replace the "+" with the zone at "ac_tail", changing the name
1209          to a ".zkey".  The name is allocated on the 'scratch' array,
1210          so we can free it afterwards. */
1211       switch (rd[i].record_type)
1212       {
1213       case GNUNET_DNSPARSER_TYPE_CNAME:
1214         {
1215           char *cname;
1216
1217           off = 0;
1218           cname = GNUNET_DNSPARSER_parse_name (rd[i].data,
1219                                                rd[i].data_size,
1220                                                &off);
1221           if ( (NULL == cname) ||
1222                (off != rd[i].data_size) )
1223           {
1224             GNUNET_break_op (0); /* record not well-formed */
1225           }
1226           else
1227           {
1228             cname = translate_dot_plus (rh, cname);
1229             scratch_start = scratch_off;
1230             if (GNUNET_OK !=
1231                 GNUNET_DNSPARSER_builder_add_name (scratch,
1232                                                    sizeof (scratch),
1233                                                    &scratch_off,
1234                                                    cname))
1235             {
1236               GNUNET_break (0);
1237             }
1238             else
1239             {
1240               rd_new[rd_off].data = &scratch[scratch_start];
1241               rd_new[rd_off].data_size = scratch_off - scratch_start;
1242               rd_off++;
1243             }
1244           }
1245           GNUNET_free_non_null (cname);
1246         }
1247         break;
1248       case GNUNET_DNSPARSER_TYPE_SOA:
1249         {
1250           struct GNUNET_DNSPARSER_SoaRecord *soa;
1251
1252           off = 0;
1253           soa = GNUNET_DNSPARSER_parse_soa (rd[i].data,
1254                                             rd[i].data_size,
1255                                             &off);
1256           if ( (NULL == soa) ||
1257                (off != rd[i].data_size) )
1258           {
1259             GNUNET_break_op (0); /* record not well-formed */
1260           }
1261           else
1262           {
1263             soa->mname = translate_dot_plus (rh, soa->mname);
1264             soa->rname = translate_dot_plus (rh, soa->rname);
1265             scratch_start = scratch_off;
1266             if (GNUNET_OK !=
1267                 GNUNET_DNSPARSER_builder_add_soa (scratch,
1268                                                   sizeof (scratch),
1269                                                   &scratch_off,
1270                                                   soa))
1271             {
1272               GNUNET_break (0);
1273             }
1274             else
1275             {
1276               rd_new[rd_off].data = &scratch[scratch_start];
1277               rd_new[rd_off].data_size = scratch_off - scratch_start;
1278               rd_off++;
1279             }
1280           }
1281           if (NULL != soa)
1282             GNUNET_DNSPARSER_free_soa (soa);
1283         }
1284         break;
1285       case GNUNET_DNSPARSER_TYPE_MX:
1286         {
1287           struct GNUNET_DNSPARSER_MxRecord *mx;
1288
1289           off = 0;
1290           mx = GNUNET_DNSPARSER_parse_mx (rd[i].data,
1291                                           rd[i].data_size,
1292                                           &off);
1293           if ( (NULL == mx) ||
1294                (off != rd[i].data_size) )
1295           {
1296             GNUNET_break_op (0); /* record not well-formed */
1297           }
1298           else
1299           {
1300             mx->mxhost = translate_dot_plus (rh, mx->mxhost);
1301             scratch_start = scratch_off;
1302             if (GNUNET_OK !=
1303                 GNUNET_DNSPARSER_builder_add_mx (scratch,
1304                                                  sizeof (scratch),
1305                                                  &scratch_off,
1306                                                  mx))
1307             {
1308               GNUNET_break (0);
1309             }
1310             else
1311             {
1312               rd_new[rd_off].data = &scratch[scratch_start];
1313               rd_new[rd_off].data_size = scratch_off - scratch_start;
1314               rd_off++;
1315             }
1316           }
1317           if (NULL != mx)
1318             GNUNET_DNSPARSER_free_mx (mx);
1319         }
1320         break;
1321       case GNUNET_DNSPARSER_TYPE_SRV:
1322         {
1323           struct GNUNET_DNSPARSER_SrvRecord *srv;
1324
1325           off = 0;
1326           /* FIXME: passing rh->name here is is not necessarily what we want
1327              (SRV support not finished) */
1328           srv = GNUNET_DNSPARSER_parse_srv (rh->name,
1329                                             rd[i].data,
1330                                             rd[i].data_size,
1331                                             &off);
1332           if ( (NULL == srv) ||
1333                (off != rd[i].data_size) )
1334           {
1335             GNUNET_break_op (0); /* record not well-formed */
1336           }
1337           else
1338           {
1339             srv->domain_name = translate_dot_plus (rh, srv->domain_name);
1340             srv->target = translate_dot_plus (rh, srv->target);
1341             scratch_start = scratch_off;
1342             if (GNUNET_OK !=
1343                 GNUNET_DNSPARSER_builder_add_srv (scratch,
1344                                                   sizeof (scratch),
1345                                                   &scratch_off,
1346                                                   srv))
1347             {
1348               GNUNET_break (0);
1349             }
1350             else
1351             {
1352               rd_new[rd_off].data = &scratch[scratch_start];
1353               rd_new[rd_off].data_size = scratch_off - scratch_start;
1354               rd_off++;
1355             }
1356           }
1357           if (NULL != srv)
1358             GNUNET_DNSPARSER_free_srv (srv);
1359         }
1360         break;
1361       case GNUNET_NAMESTORE_TYPE_PKEY:
1362         /* tigger shortening */
1363         if (NULL != rh->shorten_key)
1364         {
1365           struct GNUNET_CRYPTO_EccPublicSignKey pub;
1366
1367           if (rd[i].data_size != sizeof (struct GNUNET_CRYPTO_EccPublicSignKey))
1368           {
1369             GNUNET_break_op (0);
1370             break;
1371           }
1372           memcpy (&pub, rd[i].data, rd[i].data_size);
1373           GNS_shorten_start (rh->ac_tail->label,
1374                              &pub,
1375                              rh->shorten_key);
1376         }
1377         rd_off++;
1378         break;
1379       default:
1380         rd_off++;
1381         break;
1382       }
1383     }
1384
1385     /* yes, we are done, return result */
1386     rh->proc (rh->proc_cls, rd_off, rd_new);
1387     GNS_resolver_lookup_cancel (rh);
1388     return;
1389   }
1390   /* need to recurse, check if we can */
1391   for (i=0;i<rd_count;i++)
1392   {
1393     switch (rd[i].record_type)
1394     {
1395     case GNUNET_NAMESTORE_TYPE_PKEY:
1396       /* delegation to another zone */
1397       if (sizeof (struct GNUNET_CRYPTO_EccPublicSignKey) !=
1398           rd[i].data_size)
1399       {
1400         GNUNET_break_op (0);
1401         rh->proc (rh->proc_cls, 0, NULL);
1402         GNS_resolver_lookup_cancel (rh);
1403         return;
1404       }
1405       /* expand authority chain */
1406       ac = GNUNET_new (struct AuthorityChain);
1407       ac->rh = rh;
1408       ac->gns_authority = GNUNET_YES;
1409       memcpy (&ac->authority_info.gns_authority,
1410               rd[i].data,
1411               sizeof (struct GNUNET_CRYPTO_EccPublicSignKey));
1412       ac->label = resolver_lookup_get_next_label (rh);
1413       /* tigger shortening */
1414       if (NULL != rh->shorten_key)
1415         GNS_shorten_start (rh->ac_tail->label,
1416                            &ac->authority_info.gns_authority,
1417                            rh->shorten_key);
1418       /* add AC to tail */
1419       GNUNET_CONTAINER_DLL_insert_tail (rh->ac_head,
1420                                         rh->ac_tail,
1421                                         ac);
1422       /* recurse */
1423       rh->task_id = GNUNET_SCHEDULER_add_now (&recursive_resolution,
1424                                               rh);
1425       return;
1426     case GNUNET_DNSPARSER_TYPE_NS:
1427       {
1428         char *ns;
1429         /* resolution continues within DNS */
1430         if (GNUNET_DNSPARSER_MAX_NAME_LENGTH < rd[i].data_size)
1431         {
1432           GNUNET_break_op (0);
1433           rh->proc (rh->proc_cls, 0, NULL);
1434           GNS_resolver_lookup_cancel (rh);
1435           return;
1436         }
1437         /* find associated A/AAAA record */
1438         sa = NULL;
1439         sa_len = 0;
1440         for (j=0;j<rd_count;j++)
1441         {
1442           switch (rd[j].record_type)
1443             {
1444             case GNUNET_DNSPARSER_TYPE_A:
1445               if (sizeof (struct in_addr) != rd[j].data_size)
1446               {
1447                 GNUNET_break_op (0);
1448                 rh->proc (rh->proc_cls, 0, NULL);
1449                 GNS_resolver_lookup_cancel (rh);
1450                 return;
1451               }
1452               /* FIXME: might want to check if we support IPv4 here,
1453                  and otherwise skip this one and hope we find another */
1454               memset (&v4, 0, sizeof (v4));
1455               sa_len = sizeof (v4);
1456               v4.sin_family = AF_INET;
1457               v4.sin_port = htons (53);
1458 #if HAVE_SOCKADDR_IN_SIN_LEN
1459               v4.sin_len = (u_char) sa_len;
1460 #endif
1461               memcpy (&v4.sin_addr,
1462                       rd[j].data,
1463                       sizeof (struct in_addr));
1464               sa = (struct sockaddr *) &v4;
1465               break;
1466             case GNUNET_DNSPARSER_TYPE_AAAA:
1467               if (sizeof (struct in6_addr) != rd[j].data_size)
1468               {
1469                 GNUNET_break_op (0);
1470                 rh->proc (rh->proc_cls, 0, NULL);
1471                 GNS_resolver_lookup_cancel (rh);
1472                 return;
1473               }
1474               /* FIXME: might want to check if we support IPv6 here,
1475                  and otherwise skip this one and hope we find another */
1476               memset (&v6, 0, sizeof (v6));
1477               sa_len = sizeof (v6);
1478               v6.sin6_family = AF_INET6;
1479               v6.sin6_port = htons (53);
1480 #if HAVE_SOCKADDR_IN_SIN_LEN
1481               v6.sin6_len = (u_char) sa_len;
1482 #endif
1483               memcpy (&v6.sin6_addr,
1484                       rd[j].data,
1485                       sizeof (struct in6_addr));
1486               sa = (struct sockaddr *) &v6;
1487               break;
1488             default:
1489               break;
1490             }
1491           if (NULL != sa)
1492             break;
1493         }
1494         if (NULL == sa)
1495         {
1496           /* we cannot continue; NS without A/AAAA */
1497           rh->proc (rh->proc_cls, 0, NULL);
1498           GNS_resolver_lookup_cancel (rh);
1499           return;
1500         }
1501         /* expand authority chain */
1502         ac = GNUNET_new (struct AuthorityChain);
1503         ac->rh = rh;
1504         off = 0;
1505         ns = GNUNET_DNSPARSER_parse_name (rd[i].data,
1506                                           rd[i].data_size,
1507                                           &off);
1508         if ( (NULL == ns) ||
1509              (off != rd[i].data_size) )
1510         {
1511           GNUNET_break_op (0); /* record not well-formed */
1512           rh->proc (rh->proc_cls, 0, NULL);
1513           GNS_resolver_lookup_cancel (rh);
1514           return;
1515         }
1516         strcpy (ac->authority_info.dns_authority.name,
1517                 ns);
1518         memcpy (&ac->authority_info.dns_authority.dns_ip,
1519                 sa,
1520                 sa_len);
1521         /* for DNS recursion, the label is the full DNS name,
1522            created from the remainder of the GNS name and the
1523            name in the NS record */
1524         GNUNET_asprintf (&ac->label,
1525                          "%.*s%s",
1526                          (int) rh->name_resolution_pos,
1527                          rh->name,
1528                          ns);
1529         GNUNET_free (ns);
1530         GNUNET_CONTAINER_DLL_insert_tail (rh->ac_head,
1531                                           rh->ac_tail,
1532                                           ac);
1533         if (strlen (ac->label) > GNUNET_DNSPARSER_MAX_NAME_LENGTH)
1534         {
1535           GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
1536                       _("GNS lookup resulted in DNS name that is too long (`%s')\n"),
1537                       ac->label);
1538           rh->proc (rh->proc_cls, 0, NULL);
1539           GNS_resolver_lookup_cancel (rh);
1540           return;
1541         }
1542         /* recurse */
1543         rh->task_id = GNUNET_SCHEDULER_add_now (&recursive_resolution,
1544                                                 rh);
1545         return;
1546       }
1547     case GNUNET_DNSPARSER_TYPE_CNAME:
1548       {
1549         char *cname;
1550
1551         off = 0;
1552         cname = GNUNET_DNSPARSER_parse_name (rd[i].data,
1553                                              rd[i].data_size,
1554                                              &off);
1555         if ( (NULL == cname) ||
1556              (off != rd[i].data_size) )
1557         {
1558           GNUNET_break_op (0); /* record not well-formed */
1559           rh->proc (rh->proc_cls, 0, NULL);
1560           GNS_resolver_lookup_cancel (rh);
1561           return;
1562         }
1563         handle_gns_cname_result (rh,
1564                                  cname);
1565         GNUNET_free (cname);
1566         return;
1567       }
1568       /* FIXME: handle DNAME */
1569     default:
1570       /* skip */
1571       break;
1572     }
1573   }
1574   GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
1575               _("GNS lookup recursion failed (no delegation record found)\n"));
1576   rh->proc (rh->proc_cls, 0, NULL);
1577   GNS_resolver_lookup_cancel (rh);
1578 }
1579
1580
1581 /**
1582  * Function called once the namestore has completed the request for
1583  * caching a block.
1584  *
1585  * @param cls closure with the 'struct GNS_ResolverHandle'
1586  * @param success #GNUNET_OK on success
1587  * @param emsg error message
1588  */
1589 static void
1590 namestore_cache_continuation (void *cls,
1591                               int32_t success,
1592                               const char *emsg)
1593 {
1594   struct GNS_ResolverHandle *rh = cls;
1595
1596   rh->namestore_qe = NULL;
1597   if (NULL != emsg)
1598     GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
1599                 _("Failed to cache GNS resolution: %s\n"),
1600                 emsg);
1601 }
1602
1603
1604 /**
1605  * Iterator called on each result obtained for a DHT
1606  * operation that expects a reply
1607  *
1608  * @param cls closure with the `struct GNS_ResolverHandle`
1609  * @param exp when will this value expire
1610  * @param key key of the result
1611  * @param get_path peers on reply path (or NULL if not recorded)
1612  *                 [0] = datastore's first neighbor, [length - 1] = local peer
1613  * @param get_path_length number of entries in @a get_path
1614  * @param put_path peers on the PUT path (or NULL if not recorded)
1615  *                 [0] = origin, [length - 1] = datastore
1616  * @param put_path_length number of entries in @a put_path
1617  * @param type type of the result
1618  * @param size number of bytes in data
1619  * @param data pointer to the result data
1620  */
1621 static void
1622 handle_dht_response (void *cls,
1623                      struct GNUNET_TIME_Absolute exp,
1624                      const struct GNUNET_HashCode *key,
1625                      const struct GNUNET_PeerIdentity *get_path,
1626                      unsigned int get_path_length,
1627                      const struct GNUNET_PeerIdentity *put_path,
1628                      unsigned int put_path_length,
1629                      enum GNUNET_BLOCK_Type type,
1630                      size_t size, const void *data)
1631 {
1632   struct GNS_ResolverHandle *rh = cls;
1633   struct AuthorityChain *ac = rh->ac_tail;
1634   const struct GNUNET_NAMESTORE_Block *block;
1635
1636   GNUNET_DHT_get_stop (rh->get_handle);
1637   rh->get_handle = NULL;
1638   GNUNET_CONTAINER_heap_remove_node (rh->dht_heap_node);
1639   rh->dht_heap_node = NULL;
1640   if (size < sizeof (struct GNUNET_NAMESTORE_Block))
1641   {
1642     /* how did this pass DHT block validation!? */
1643     GNUNET_break (0);
1644     rh->proc (rh->proc_cls, 0, NULL);
1645     GNS_resolver_lookup_cancel (rh);
1646     return;
1647   }
1648   block = data;
1649   if (size !=
1650       ntohl (block->purpose.size) +
1651       sizeof (struct GNUNET_CRYPTO_EccPublicSignKey) +
1652       sizeof (struct GNUNET_CRYPTO_EccSignature))
1653   {
1654     /* how did this pass DHT block validation!? */
1655     GNUNET_break (0);
1656     rh->proc (rh->proc_cls, 0, NULL);
1657     GNS_resolver_lookup_cancel (rh);
1658     return;
1659   }
1660   if (GNUNET_OK !=
1661       GNUNET_NAMESTORE_block_decrypt (block,
1662                                       &ac->authority_info.gns_authority,
1663                                       ac->label,
1664                                       &handle_gns_resolution_result,
1665                                       rh))
1666   {
1667     GNUNET_break_op (0); /* block was ill-formed */
1668     rh->proc (rh->proc_cls, 0, NULL);
1669     GNS_resolver_lookup_cancel (rh);
1670     return;
1671   }
1672   /* Cache well-formed blocks */
1673   rh->namestore_qe = GNUNET_NAMESTORE_block_cache (namestore_handle,
1674                                                    block,
1675                                                    &namestore_cache_continuation,
1676                                                    rh);
1677 }
1678
1679
1680 /**
1681  * Process a record that was stored in the namestore.
1682  *
1683  * @param cls closure with the `struct GNS_ResolverHandle`
1684  * @param block block that was stored in the namestore
1685  */
1686 static void
1687 handle_namestore_block_response (void *cls,
1688                                  const struct GNUNET_NAMESTORE_Block *block)
1689 {
1690   struct GNS_ResolverHandle *rh = cls;
1691   struct GNS_ResolverHandle *rx;
1692   struct AuthorityChain *ac = rh->ac_tail;
1693   const char *label = ac->label;
1694   const struct GNUNET_CRYPTO_EccPublicSignKey *auth = &ac->authority_info.gns_authority;
1695   struct GNUNET_HashCode query;
1696
1697   GNUNET_NAMESTORE_query_from_public_key (auth,
1698                                           label,
1699                                           &query);
1700   rh->namestore_qe = NULL;
1701   if ( (GNUNET_NO == rh->only_cached) &&
1702        ( (NULL == block) ||
1703          (0 == GNUNET_TIME_absolute_get_remaining (GNUNET_TIME_absolute_ntoh (block->expiration_time)).rel_value_us) ) )
1704   {
1705     /* Namestore knows nothing; try DHT lookup */
1706     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1707                 "Starting DHT lookup for `%s' in zone %s\n",
1708                 ac->label,
1709                 GNUNET_NAMESTORE_z2s (&ac->authority_info.gns_authority));
1710     rh->get_handle = GNUNET_DHT_get_start (dht_handle,
1711                                            GNUNET_BLOCK_TYPE_GNS_NAMERECORD,
1712                                            &query,
1713                                            DHT_GNS_REPLICATION_LEVEL,
1714                                            GNUNET_DHT_RO_DEMULTIPLEX_EVERYWHERE,
1715                                            NULL, 0,
1716                                            &handle_dht_response, rh);
1717     rh->dht_heap_node = GNUNET_CONTAINER_heap_insert (dht_lookup_heap,
1718                                                       rh,
1719                                                       GNUNET_TIME_absolute_get ().abs_value_us);
1720     if (GNUNET_CONTAINER_heap_get_size (dht_lookup_heap) > max_allowed_background_queries)
1721     {
1722       /* fail longest-standing DHT request */
1723       rx = GNUNET_CONTAINER_heap_peek (dht_lookup_heap);
1724       GNUNET_assert (NULL != rx);
1725       rx->proc (rx->proc_cls, 0, NULL);
1726       GNS_resolver_lookup_cancel (rx);
1727     }
1728     return;
1729   }
1730   if ( (NULL == block) ||
1731        (0 == GNUNET_TIME_absolute_get_remaining (GNUNET_TIME_absolute_ntoh (block->expiration_time)).rel_value_us) )
1732   {
1733     /* DHT not permitted and no local result, fail */
1734     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1735                 "Resolution failed for `%s' in zone %s (DHT lookup not permitted by configuration)\n",
1736                 ac->label,
1737                 GNUNET_NAMESTORE_z2s (&ac->authority_info.gns_authority));
1738     rh->proc (rh->proc_cls, 0, NULL);
1739     GNS_resolver_lookup_cancel (rh);
1740     return;
1741   }
1742   if (GNUNET_OK !=
1743       GNUNET_NAMESTORE_block_decrypt (block,
1744                                       auth,
1745                                       label,
1746                                       &handle_gns_resolution_result,
1747                                       rh))
1748   {
1749     GNUNET_break_op (0); /* block was ill-formed */
1750     rh->proc (rh->proc_cls, 0, NULL);
1751     GNS_resolver_lookup_cancel (rh);
1752     return;
1753   }
1754 }
1755
1756
1757 /**
1758  * Lookup tail of our authority chain in the namestore.
1759  *
1760  * @param rh query we are processing
1761  */
1762 static void
1763 recursive_gns_resolution_namestore (struct GNS_ResolverHandle *rh)
1764 {
1765   struct AuthorityChain *ac = rh->ac_tail;
1766   struct GNUNET_HashCode query;
1767
1768   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1769               "Starting GNS resolution for `%s' in zone %s\n",
1770               ac->label,
1771               GNUNET_NAMESTORE_z2s (&ac->authority_info.gns_authority));
1772   GNUNET_NAMESTORE_query_from_public_key (&ac->authority_info.gns_authority,
1773                                           ac->label,
1774                                           &query);
1775   rh->namestore_qe = GNUNET_NAMESTORE_lookup_block (namestore_handle,
1776                                                     &query,
1777                                                     &handle_namestore_block_response,
1778                                                     rh);
1779 }
1780
1781
1782 /**
1783  * Task scheduled to continue with the resolution process.
1784  *
1785  * @param cls the `struct GNS_ResolverHandle` of the resolution
1786  * @param tc task context
1787  */
1788 static void
1789 recursive_resolution (void *cls,
1790                       const struct GNUNET_SCHEDULER_TaskContext *tc)
1791 {
1792   struct GNS_ResolverHandle *rh = cls;
1793
1794   rh->task_id = GNUNET_SCHEDULER_NO_TASK;
1795   if (MAX_RECURSION < rh->loop_limiter++)
1796   {
1797     GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
1798                 "Encountered unbounded recursion resolving `%s'\n",
1799                 rh->name);
1800     rh->proc (rh->proc_cls, 0, NULL);
1801     GNS_resolver_lookup_cancel (rh);
1802     return;
1803   }
1804   if (GNUNET_YES == rh->ac_tail->gns_authority)
1805     recursive_gns_resolution_namestore (rh);
1806   else
1807     recursive_dns_resolution (rh);
1808 }
1809
1810
1811 /**
1812  * Begin the resolution process from 'name', starting with
1813  * the identification of the zone specified by 'name'.
1814  *
1815  * @param rh resolution to perform
1816  */
1817 static void
1818 start_resolver_lookup (struct GNS_ResolverHandle *rh)
1819 {
1820   struct AuthorityChain *ac;
1821   char *x;
1822   char *y;
1823   char *pkey;
1824
1825   if ( ( (GNUNET_YES == is_canonical (rh->name)) &&
1826          (0 != strcmp (GNUNET_GNS_TLD, rh->name)) ) ||
1827        ( (GNUNET_YES != is_gnu_tld (rh->name)) &&
1828          (GNUNET_YES != is_zkey_tld (rh->name)) ) )
1829   {
1830     /* use standard DNS lookup */
1831     int af;
1832
1833     switch (rh->record_type)
1834     {
1835     case GNUNET_DNSPARSER_TYPE_A:
1836       af = AF_INET;
1837       break;
1838     case GNUNET_DNSPARSER_TYPE_AAAA:
1839       af = AF_INET6;
1840       break;
1841     default:
1842       af = AF_UNSPEC;
1843       break;
1844     }
1845     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1846                 "Doing standard DNS lookup for `%s'\n",
1847                 rh->name);
1848     rh->std_resolve = GNUNET_RESOLVER_ip_get (rh->name,
1849                                               af,
1850                                               DNS_LOOKUP_TIMEOUT,
1851                                               &handle_dns_result,
1852                                               rh);
1853     return;
1854   }
1855   if (is_zkey_tld (rh->name))
1856   {
1857     /* Name ends with ".zkey", try to replace authority zone with zkey
1858        authority */
1859     GNUNET_free (resolver_lookup_get_next_label (rh)); /* will return "zkey" */
1860     x = resolver_lookup_get_next_label (rh); /* will return 'x' coordinate */
1861     y = resolver_lookup_get_next_label (rh); /* will return 'y' coordinate */
1862     GNUNET_asprintf (&pkey,
1863                      "%s%s",
1864                      x, y);
1865     if ( (NULL == x) ||
1866          (NULL == y) ||
1867          (GNUNET_OK !=
1868           GNUNET_CRYPTO_ecc_public_sign_key_from_string (pkey,
1869                                                     strlen (pkey),
1870                                                     &rh->authority_zone)) )
1871     {
1872       GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
1873                   _("Hostname `%s' is not well-formed, resolution fails\n"),
1874                   rh->name);
1875       rh->task_id = GNUNET_SCHEDULER_add_now (&fail_resolution, rh);
1876     }
1877     GNUNET_free_non_null (x);
1878     GNUNET_free_non_null (y);
1879     GNUNET_free (pkey);
1880   }
1881   else
1882   {
1883     /* Name ends with ".gnu", eat ".gnu" and continue with resolution */
1884     GNUNET_free (resolver_lookup_get_next_label (rh));
1885   }
1886   ac = GNUNET_new (struct AuthorityChain);
1887   ac->rh = rh;
1888   ac->label = resolver_lookup_get_next_label (rh);
1889   if (NULL == ac->label)
1890     /* name was just "gnu", so we default to label '+' */
1891     ac->label = GNUNET_strdup (GNUNET_GNS_MASTERZONE_STR);
1892   ac->gns_authority = GNUNET_YES;
1893   ac->authority_info.gns_authority = rh->authority_zone;
1894   GNUNET_CONTAINER_DLL_insert_tail (rh->ac_head,
1895                                     rh->ac_tail,
1896                                     ac);
1897   rh->task_id = GNUNET_SCHEDULER_add_now (&recursive_resolution,
1898                                           rh);
1899 }
1900
1901
1902 /**
1903  * Lookup of a record in a specific zone calls lookup result processor
1904  * on result.
1905  *
1906  * @param zone the zone to perform the lookup in
1907  * @param record_type the record type to look up
1908  * @param name the name to look up
1909  * @param shorten_key a private key for use with PSEU import (can be NULL)
1910  * @param only_cached #GNUNET_NO to only check locally not DHT for performance
1911  * @param proc the processor to call on result
1912  * @param proc_cls the closure to pass to @a proc
1913  * @return handle to cancel operation
1914  */
1915 struct GNS_ResolverHandle *
1916 GNS_resolver_lookup (const struct GNUNET_CRYPTO_EccPublicSignKey *zone,
1917                      uint32_t record_type,
1918                      const char *name,
1919                      const struct GNUNET_CRYPTO_EccPrivateKey *shorten_key,
1920                      int only_cached,
1921                      GNS_ResultProcessor proc, void *proc_cls)
1922 {
1923   struct GNS_ResolverHandle *rh;
1924
1925   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1926               "Starting lookup for `%s'\n",
1927               name);
1928   rh = GNUNET_new (struct GNS_ResolverHandle);
1929   GNUNET_CONTAINER_DLL_insert (rlh_head,
1930                                rlh_tail,
1931                                rh);
1932   rh->authority_zone = *zone;
1933   rh->proc = proc;
1934   rh->proc_cls = proc_cls;
1935   rh->only_cached = only_cached;
1936   rh->record_type = record_type;
1937   rh->name = GNUNET_strdup (name);
1938   rh->name_resolution_pos = strlen (name);
1939   if (NULL != shorten_key)
1940   {
1941     rh->shorten_key = GNUNET_new (struct GNUNET_CRYPTO_EccPrivateKey);
1942     *rh->shorten_key = *shorten_key;
1943   }
1944   start_resolver_lookup (rh);
1945   return rh;
1946 }
1947
1948
1949 /**
1950  * Cancel active resolution (i.e. client disconnected).
1951  *
1952  * @param rh resolution to abort
1953  */
1954 void
1955 GNS_resolver_lookup_cancel (struct GNS_ResolverHandle *rh)
1956 {
1957   struct DnsResult *dr;
1958   struct AuthorityChain *ac;
1959   struct VpnContext *vpn_ctx;
1960
1961   GNUNET_CONTAINER_DLL_remove (rlh_head,
1962                                rlh_tail,
1963                                rh);
1964   while (NULL != (ac = rh->ac_head))
1965   {
1966     GNUNET_CONTAINER_DLL_remove (rh->ac_head,
1967                                  rh->ac_tail,
1968                                  ac);
1969     GNUNET_free (ac->label);
1970     GNUNET_free (ac);
1971   }
1972   if (GNUNET_SCHEDULER_NO_TASK != rh->task_id)
1973   {
1974     GNUNET_SCHEDULER_cancel (rh->task_id);
1975     rh->task_id = GNUNET_SCHEDULER_NO_TASK;
1976   }
1977   if (NULL != rh->get_handle)
1978   {
1979     GNUNET_DHT_get_stop (rh->get_handle);
1980     rh->get_handle = NULL;
1981   }
1982   if (NULL != rh->dht_heap_node)
1983   {
1984     GNUNET_CONTAINER_heap_remove_node (rh->dht_heap_node);
1985     rh->dht_heap_node = NULL;
1986   }
1987   if (NULL != (vpn_ctx = rh->vpn_ctx))
1988   {
1989     GNUNET_VPN_cancel_request (vpn_ctx->vpn_request);
1990     GNUNET_free (vpn_ctx->rd_data);
1991     GNUNET_free (vpn_ctx);
1992   }
1993   if (NULL != rh->dns_request)
1994   {
1995     GNUNET_DNSSTUB_resolve_cancel (rh->dns_request);
1996     rh->dns_request = NULL;
1997   }
1998   if (NULL != rh->namestore_qe)
1999   {
2000     GNUNET_NAMESTORE_cancel (rh->namestore_qe);
2001     rh->namestore_qe = NULL;
2002   }
2003   if (NULL != rh->std_resolve)
2004   {
2005     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
2006                 "Canceling standard DNS resolution\n");
2007     GNUNET_RESOLVER_request_cancel (rh->std_resolve);
2008     rh->std_resolve = NULL;
2009   }
2010   while (NULL != (dr = rh->dns_result_head))
2011   {
2012     GNUNET_CONTAINER_DLL_remove (rh->dns_result_head,
2013                                  rh->dns_result_tail,
2014                                  dr);
2015     GNUNET_free (dr);
2016   }
2017   GNUNET_free_non_null (rh->shorten_key);
2018   GNUNET_free (rh->name);
2019   GNUNET_free (rh);
2020 }
2021
2022
2023 /* ***************** Resolver initialization ********************* */
2024
2025
2026 /**
2027  * Initialize the resolver
2028  *
2029  * @param nh the namestore handle
2030  * @param dht the dht handle
2031  * @param c configuration handle
2032  * @param max_bg_queries maximum number of parallel background queries in dht
2033  */
2034 void
2035 GNS_resolver_init (struct GNUNET_NAMESTORE_Handle *nh,
2036                    struct GNUNET_DHT_Handle *dht,
2037                    const struct GNUNET_CONFIGURATION_Handle *c,
2038                    unsigned long long max_bg_queries)
2039 {
2040   char *dns_ip;
2041
2042   cfg = c;
2043   namestore_handle = nh;
2044   dht_handle = dht;
2045   dht_lookup_heap =
2046     GNUNET_CONTAINER_heap_create (GNUNET_CONTAINER_HEAP_ORDER_MIN);
2047   max_allowed_background_queries = max_bg_queries;
2048   if (GNUNET_OK !=
2049       GNUNET_CONFIGURATION_get_value_string (c,
2050                                              "gns",
2051                                              "DNS_RESOLVER",
2052                                              &dns_ip))
2053   {
2054     /* user did not specify DNS resolver, use 8.8.8.8 */
2055     dns_ip = GNUNET_strdup ("8.8.8.8");
2056   }
2057   dns_handle = GNUNET_DNSSTUB_start (dns_ip);
2058   GNUNET_free (dns_ip);
2059   vpn_handle = GNUNET_VPN_connect (cfg);
2060 }
2061
2062
2063 /**
2064  * Shutdown resolver
2065  */
2066 void
2067 GNS_resolver_done ()
2068 {
2069   struct GNS_ResolverHandle *rh;
2070
2071   /* abort active resolutions */
2072   while (NULL != (rh = rlh_head))
2073   {
2074     rh->proc (rh->proc_cls, 0, NULL);
2075     GNS_resolver_lookup_cancel (rh);
2076   }
2077   GNUNET_CONTAINER_heap_destroy (dht_lookup_heap);
2078   dht_lookup_heap = NULL;
2079   GNUNET_DNSSTUB_stop (dns_handle);
2080   dns_handle = NULL;
2081   GNUNET_VPN_disconnect (vpn_handle);
2082   vpn_handle = NULL;
2083   dht_handle = NULL;
2084   namestore_handle = NULL;
2085 }
2086
2087
2088 /* *************** common helper functions (do not really belong here) *********** */
2089
2090 /**
2091  * Checks if @a name ends in ".TLD"
2092  *
2093  * @param name the name to check
2094  * @param tld the TLD to check for
2095  * @return GNUNET_YES or GNUNET_NO
2096  */
2097 int
2098 is_tld (const char* name, const char* tld)
2099 {
2100   size_t offset = 0;
2101
2102   if (strlen (name) <= strlen (tld))
2103     return GNUNET_NO;
2104   offset = strlen (name) - strlen (tld);
2105   if (0 != strcmp (name + offset, tld))
2106     return GNUNET_NO;
2107   return GNUNET_YES;
2108 }
2109
2110
2111 /* end of gnunet-service-gns_resolver.c */