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   const 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     size_t buf_start;
 756
 757     buf_off = 0;
 758     skip = 0;
 759     memset (rd, 0, sizeof (rd));
 760     for (i=0;i<rd_count;i++)
 761     {
 762       if (i < p->num_answers)
 763         rec = &p->answers[i];
 764       else if (i < p->num_answers + p->num_authority_records)
 765         rec = &p->authority_records[i - p->num_answers];
 766       else
 767         rec = &p->authority_records[i - p->num_answers - p->num_authority_records];
 768       /* As we copied the full DNS name to 'rh->ac_tail->label', this
 769          should be the correct check to see if this record is actually
 770          a record for our label... */
 771       if (0 != strcmp (rec->name,
 772                        rh->ac_tail->label))
 773       {
 774         GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 775                     "Dropping record `%s', does not match desired name `%s'\n",
 776                     rec->name,
 777                     rh->ac_tail->label);
 778         skip++;
 779         continue;
 780       }
 781       rd[i - skip].record_type = rec->type;
 782       rd[i - skip].expiration_time = rec->expiration_time.abs_value_us;
 783       switch (rec->type)
 784       {
 785       case GNUNET_DNSPARSER_TYPE_A:
 786         if (rec->data.raw.data_len != sizeof (struct in_addr))
 787         {
 788           GNUNET_break_op (0);
 789           skip++;
 790           continue;
 791         }
 792         rd[i - skip].data_size = rec->data.raw.data_len;
 793         rd[i - skip].data = rec->data.raw.data;
 794         break;
 795       case GNUNET_DNSPARSER_TYPE_AAAA:
 796         if (rec->data.raw.data_len != sizeof (struct in6_addr))
 797         {
 798           GNUNET_break_op (0);
 799           skip++;
 800           continue;
 801         }
 802         rd[i - skip].data_size = rec->data.raw.data_len;
 803         rd[i - skip].data = rec->data.raw.data;
 804         break;
 805       case GNUNET_DNSPARSER_TYPE_CNAME:
 806       case GNUNET_DNSPARSER_TYPE_PTR:
 807       case GNUNET_DNSPARSER_TYPE_NS:
 808         buf_start = buf_off;
 809         if (GNUNET_OK !=
 810             GNUNET_DNSPARSER_builder_add_name (buf,
 811                                                sizeof (buf),
 812                                                &buf_off,
 813                                                rec->data.hostname))
 814         {
 815           GNUNET_break (0);
 816           skip++;
 817           continue;
 818         }
 819         rd[i - skip].data_size = buf_off - buf_start;
 820         rd[i - skip].data = &buf[buf_start];
 821         break;
 822       case GNUNET_DNSPARSER_TYPE_SOA:
 823         buf_start = buf_off;
 824         if (GNUNET_OK !=
 825             GNUNET_DNSPARSER_builder_add_soa (buf,
 826                                                sizeof (buf),
 827                                                &buf_off,
 828                                                rec->data.soa))
 829         {
 830           GNUNET_break (0);
 831           skip++;
 832           continue;
 833         }
 834         rd[i - skip].data_size = buf_off - buf_start;
 835         rd[i - skip].data = &buf[buf_start];
 836         break;
 837       case GNUNET_DNSPARSER_TYPE_MX:
 838         buf_start = buf_off;
 839         if (GNUNET_OK !=
 840             GNUNET_DNSPARSER_builder_add_mx (buf,
 841                                              sizeof (buf),
 842                                              &buf_off,
 843                                              rec->data.mx))
 844         {
 845           GNUNET_break (0);
 846           skip++;
 847           continue;
 848         }
 849         rd[i - skip].data_size = buf_off - buf_start;
 850         rd[i - skip].data = &buf[buf_start];
 851         break;
 852       case GNUNET_DNSPARSER_TYPE_SRV:
 853         buf_start = buf_off;
 854         if (GNUNET_OK !=
 855             GNUNET_DNSPARSER_builder_add_srv (buf,
 856                                               sizeof (buf),
 857                                               &buf_off,
 858                                               rec->data.srv))
 859         {
 860           GNUNET_break (0);
 861           skip++;
 862           continue;
 863         }
 864         rd[i - skip].data_size = buf_off - buf_start;
 865         rd[i - skip].data = &buf[buf_start];
 866         break;
 867       default:
 868         GNUNET_log (GNUNET_ERROR_TYPE_INFO,
 869                     _("Skipping record of unsupported type %d\n"),
 870                     rec->type);
 871         skip++;
 872         continue;
 873       }
 874     }
 875     rh->proc (rh->proc_cls, rd_count - skip, rd);
 876     GNS_resolver_lookup_cancel (rh);
 877   }
 878   GNUNET_DNSPARSER_free_packet (p);
 879 }
 880
 881
 882 /**
 883  * Perform recursive DNS resolution.  Asks the given DNS resolver to
 884  * resolve "rh->dns_name", possibly recursively proceeding following
 885  * NS delegations, CNAMES, etc., until 'rh->loop_limiter' bounds us or
 886  * we find the answer.
 887  *
 888  * @param rh resolution information
 889  */
 890 static void
 891 recursive_dns_resolution (struct GNS_ResolverHandle *rh)
 892 {
 893   struct AuthorityChain *ac;
 894   socklen_t sa_len;
 895   struct GNUNET_DNSPARSER_Query *query;
 896   struct GNUNET_DNSPARSER_Packet *p;
 897   char *dns_request;
 898   size_t dns_request_length;
 899
 900   ac = rh->ac_tail;
 901   GNUNET_assert (NULL != ac);
 902   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 903               "Starting DNS lookup for `%s'\n",
 904               ac->label);
 905   GNUNET_assert (GNUNET_NO == ac->gns_authority);
 906   switch (((const struct sockaddr *) &ac->authority_info.dns_authority.dns_ip)->sa_family)
 907   {
 908   case AF_INET:
 909     sa_len = sizeof (struct sockaddr_in);
 910     break;
 911   case AF_INET6:
 912     sa_len = sizeof (struct sockaddr_in6);
 913     break;
 914   default:
 915     GNUNET_break (0);
 916     rh->proc (rh->proc_cls, 0, NULL);
 917     GNS_resolver_lookup_cancel (rh);
 918     return;
 919   }
 920   query = GNUNET_new (struct GNUNET_DNSPARSER_Query);
 921   query->name = GNUNET_strdup (ac->label);
 922   query->type = rh->record_type;
 923   query->class = GNUNET_TUN_DNS_CLASS_INTERNET;
 924   p = GNUNET_new (struct GNUNET_DNSPARSER_Packet);
 925   p->queries = query;
 926   p->num_queries = 1;
 927   p->id = (uint16_t) GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE,
 928                                                UINT16_MAX);
 929   p->flags.opcode = GNUNET_TUN_DNS_OPCODE_QUERY;
 930   p->flags.recursion_desired = 1;
 931   if (GNUNET_OK !=
 932       GNUNET_DNSPARSER_pack (p, 1024, &dns_request, &dns_request_length))
 933   {
 934     GNUNET_break (0);
 935     rh->proc (rh->proc_cls, 0, NULL);
 936     GNS_resolver_lookup_cancel (rh);
 937   }
 938   else
 939   {
 940     rh->dns_request = GNUNET_DNSSTUB_resolve (dns_handle,
 941                                               (const struct sockaddr *) &ac->authority_info.dns_authority.dns_ip,
 942                                               sa_len,
 943                                               dns_request,
 944                                               dns_request_length,
 945                                               &dns_result_parser,
 946                                               rh);
 947     rh->task_id = GNUNET_SCHEDULER_add_delayed (DNS_LOOKUP_TIMEOUT,
 948                                                 &fail_resolution,
 949                                                 rh);
 950   }
 951   GNUNET_free (dns_request);
 952   GNUNET_DNSPARSER_free_packet (p);
 953 }
 954
 955
 956 /**
 957  * We encountered a CNAME record during our resolution.
 958  * Merge it into our chain.
 959  *
 960  * @param rh resolution we are performing
 961  * @param cname value of the cname record we got for the current
 962  *        authority chain tail
 963  */
 964 static void
 965 handle_gns_cname_result (struct GNS_ResolverHandle *rh,
 966                          const char *cname)
 967 {
 968   size_t nlen;
 969   char *res;
 970   struct AuthorityChain *ac;
 971
 972   nlen = strlen (cname);
 973   if ( (nlen > 2) &&
 974        (0 == strcmp (".+",
 975                      &cname[nlen - 2])) )
 976   {
 977     /* CNAME resolution continues relative to current domain */
 978     if (0 == rh->name_resolution_pos)
 979     {
 980       res = GNUNET_strndup (cname, nlen - 2);
 981       rh->name_resolution_pos = nlen - 2;
 982     }
 983     else
 984     {
 985       GNUNET_asprintf (&res,
 986                        "%.*s.%.*s",
 987                        (int) rh->name_resolution_pos,
 988                        rh->name,
 989                        (int) (nlen - 2),
 990                        cname);
 991       rh->name_resolution_pos = strlen (res);
 992     }
 993     GNUNET_free (rh->name);
 994     rh->name = res;
 995     ac = GNUNET_new (struct AuthorityChain);
 996     ac->rh = rh;
 997     ac->gns_authority = GNUNET_YES;
 998     ac->authority_info.gns_authority = rh->ac_tail->authority_info.gns_authority;
 999     ac->label = resolver_lookup_get_next_label (rh);
1000     /* tigger shortening */
1001     if (NULL != rh->shorten_key)
1002       GNS_shorten_start (rh->ac_tail->label,
1003                          &ac->authority_info.gns_authority,
1004                          rh->shorten_key);
1005     /* add AC to tail */
1006     GNUNET_CONTAINER_DLL_insert_tail (rh->ac_head,
1007                                       rh->ac_tail,
1008                                       ac);
1009     rh->task_id = GNUNET_SCHEDULER_add_now (&recursive_resolution,
1010                                             rh);
1011     return;
1012   }
1013   /* name is absolute, start from the beginning */
1014   GNUNET_free (rh->name);
1015   rh->name = GNUNET_strdup (cname);
1016   start_resolver_lookup (rh);
1017 }
1018
1019
1020 /**
1021  * Process a records that were decrypted from a block.
1022  *
1023  * @param cls closure with the 'struct GNS_ResolverHandle'
1024  * @param rd_count number of entries in @a rd array
1025  * @param rd array of records with data to store
1026  */
1027 static void
1028 handle_gns_resolution_result (void *cls,
1029                               unsigned int rd_count,
1030                               const struct GNUNET_NAMESTORE_RecordData *rd);
1031
1032
1033 /**
1034  * Callback invoked from the VPN service once a redirection is
1035  * available.  Provides the IP address that can now be used to
1036  * reach the requested destination.  Replaces the "VPN" record
1037  * with the respective A/AAAA record and continues processing.
1038  *
1039  * @param cls closure
1040  * @param af address family, AF_INET or AF_INET6; AF_UNSPEC on error;
1041  *                will match 'result_af' from the request
1042  * @param address IP address (struct in_addr or struct in_addr6, depending on 'af')
1043  *                that the VPN allocated for the redirection;
1044  *                traffic to this IP will now be redirected to the
1045  *                specified target peer; NULL on error
1046  */
1047 static void
1048 vpn_allocation_cb (void *cls,
1049                    int af,
1050                    const void *address)
1051 {
1052   struct VpnContext *vpn_ctx = cls;
1053   struct GNS_ResolverHandle *rh = vpn_ctx->rh;
1054   struct GNUNET_NAMESTORE_RecordData rd[vpn_ctx->rd_count];
1055   unsigned int i;
1056
1057   vpn_ctx->vpn_request = NULL;
1058   rh->vpn_ctx = NULL;
1059   GNUNET_assert (GNUNET_OK ==
1060                  GNUNET_NAMESTORE_records_deserialize (vpn_ctx->rd_data_size,
1061                                                        vpn_ctx->rd_data,
1062                                                        vpn_ctx->rd_count,
1063                                                        rd));
1064   for (i=0;i<vpn_ctx->rd_count;i++)
1065   {
1066     if (GNUNET_NAMESTORE_TYPE_VPN == rd[i].record_type)
1067     {
1068       switch (af)
1069       {
1070       case AF_INET:
1071         rd[i].record_type = GNUNET_DNSPARSER_TYPE_A;
1072         rd[i].data_size = sizeof (struct in_addr);
1073         rd[i].expiration_time = GNUNET_TIME_relative_to_absolute (VPN_TIMEOUT).abs_value_us;
1074         rd[i].flags = 0;
1075         rd[i].data = address;
1076         break;
1077       case AF_INET6:
1078         rd[i].record_type = GNUNET_DNSPARSER_TYPE_AAAA;
1079         rd[i].expiration_time = GNUNET_TIME_relative_to_absolute (VPN_TIMEOUT).abs_value_us;
1080         rd[i].flags = 0;
1081         rd[i].data = address;
1082         rd[i].data_size = sizeof (struct in6_addr);
1083         break;
1084       default:
1085         GNUNET_assert (0);
1086       }
1087       break;
1088     }
1089   }
1090   GNUNET_assert (i < vpn_ctx->rd_count);
1091   handle_gns_resolution_result (rh,
1092                                 vpn_ctx->rd_count,
1093                                 rd);
1094   GNUNET_free (vpn_ctx->rd_data);
1095   GNUNET_free (vpn_ctx);
1096 }
1097
1098
1099 /**
1100  * Process a records that were decrypted from a block.
1101  *
1102  * @param cls closure with the `struct GNS_ResolverHandle`
1103  * @param rd_count number of entries in @a rd array
1104  * @param rd array of records with data to store
1105  */
1106 static void
1107 handle_gns_resolution_result (void *cls,
1108                               unsigned int rd_count,
1109                               const struct GNUNET_NAMESTORE_RecordData *rd)
1110 {
1111   struct GNS_ResolverHandle *rh = cls;
1112   struct AuthorityChain *ac;
1113   unsigned int i;
1114   unsigned int j;
1115   struct sockaddr *sa;
1116   struct sockaddr_in v4;
1117   struct sockaddr_in6 v6;
1118   size_t sa_len;
1119   char *cname;
1120   struct VpnContext *vpn_ctx;
1121   const struct GNUNET_TUN_GnsVpnRecord *vpn;
1122   const char *vname;
1123   struct GNUNET_HashCode vhash;
1124   int af;
1125   char scratch[UINT16_MAX];
1126   size_t scratch_off;
1127   size_t scratch_start;
1128   size_t off;
1129   struct GNUNET_NAMESTORE_RecordData rd_new[rd_count];
1130   unsigned int rd_off;
1131
1132   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1133               "Resolution succeeded for `%s' in zone %s, got %u records\n",
1134               rh->ac_tail->label,
1135               GNUNET_NAMESTORE_z2s (&rh->ac_tail->authority_info.gns_authority),
1136               rd_count);
1137   if (0 == rh->name_resolution_pos)
1138   {
1139     /* top-level match, are we done yet? */
1140     if ( (rd_count > 0) &&
1141          (GNUNET_DNSPARSER_TYPE_CNAME == rd[0].record_type) &&
1142          (GNUNET_DNSPARSER_TYPE_CNAME != rh->record_type) )
1143     {
1144       off = 0;
1145       cname = GNUNET_DNSPARSER_parse_name (rd[0].data,
1146                                            rd[0].data_size,
1147                                            &off);
1148       if ( (NULL == cname) ||
1149            (off != rd[0].data_size) )
1150       {
1151         GNUNET_break_op (0);
1152         rh->proc (rh->proc_cls, 0, NULL);
1153         GNS_resolver_lookup_cancel (rh);
1154         return;
1155       }
1156       handle_gns_cname_result (rh,
1157                                cname);
1158       GNUNET_free (cname);
1159       return;
1160     }
1161     /* If A/AAAA was requested, but we got a VPN
1162        record, we convert it to A/AAAA using GNUnet VPN */
1163     if ( (GNUNET_DNSPARSER_TYPE_A == rh->record_type) ||
1164          (GNUNET_DNSPARSER_TYPE_AAAA == rh->record_type) )
1165     {
1166       for (i=0;i<rd_count;i++)
1167       {
1168         switch (rd[i].record_type)
1169         {
1170         case GNUNET_NAMESTORE_TYPE_VPN:
1171           {
1172             af = (GNUNET_DNSPARSER_TYPE_A == rh->record_type) ? AF_INET : AF_INET6;
1173             if (sizeof (struct GNUNET_TUN_GnsVpnRecord) <
1174                 rd[i].data_size)
1175             {
1176               GNUNET_break_op (0);
1177               rh->proc (rh->proc_cls, 0, NULL);
1178               GNS_resolver_lookup_cancel (rh);
1179               return;
1180             }
1181             vpn = (const struct GNUNET_TUN_GnsVpnRecord *) rd[i].data;
1182             vname = (const char *) &vpn[1];
1183             if ('\0' != vname[rd[i].data_size - 1 - sizeof (struct GNUNET_TUN_GnsVpnRecord)])
1184             {
1185               GNUNET_break_op (0);
1186               rh->proc (rh->proc_cls, 0, NULL);
1187               GNS_resolver_lookup_cancel (rh);
1188               return;
1189             }
1190             GNUNET_CRYPTO_hash (vname,
1191                                 strlen (vname), // FIXME: +1?
1192                                 &vhash);
1193             vpn_ctx = GNUNET_new (struct VpnContext);
1194             rh->vpn_ctx = vpn_ctx;
1195             vpn_ctx->rh = rh;
1196             vpn_ctx->rd_data_size = GNUNET_NAMESTORE_records_get_size (rd_count,
1197                                                                        rd);
1198             vpn_ctx->rd_data = GNUNET_malloc (vpn_ctx->rd_data_size);
1199             (void) GNUNET_NAMESTORE_records_serialize (rd_count,
1200                                                        rd,
1201                                                        vpn_ctx->rd_data_size,
1202                                                        vpn_ctx->rd_data);
1203             vpn_ctx->vpn_request = GNUNET_VPN_redirect_to_peer (vpn_handle,
1204                                                                 af,
1205                                                                 ntohs (vpn->proto),
1206                                                                 &vpn->peer,
1207                                                                 &vhash,
1208                                                                 GNUNET_TIME_relative_to_absolute (VPN_TIMEOUT),
1209                                                                 &vpn_allocation_cb,
1210                                                                 rh);
1211             return;
1212           }
1213         case GNUNET_NAMESTORE_TYPE_GNS2DNS:
1214           {
1215             /* delegation to DNS */
1216             goto do_recurse;
1217           }
1218         default:
1219           break;
1220         }
1221       }
1222     }
1223     /* convert relative names in record values to absolute names,
1224        using 'scratch' array for memory allocations */
1225     scratch_off = 0;
1226     rd_off = 0;
1227     for (i=0;i<rd_count;i++)
1228     {
1229       rd_new[rd_off] = rd[i];
1230       /* Check if the embedded name(s) end in "+", and if so,
1231          replace the "+" with the zone at "ac_tail", changing the name
1232          to a ".zkey".  The name is allocated on the 'scratch' array,
1233          so we can free it afterwards. */
1234       switch (rd[i].record_type)
1235       {
1236       case GNUNET_DNSPARSER_TYPE_CNAME:
1237         {
1238           char *cname;
1239
1240           off = 0;
1241           cname = GNUNET_DNSPARSER_parse_name (rd[i].data,
1242                                                rd[i].data_size,
1243                                                &off);
1244           if ( (NULL == cname) ||
1245                (off != rd[i].data_size) )
1246           {
1247             GNUNET_break_op (0); /* record not well-formed */
1248           }
1249           else
1250           {
1251             cname = translate_dot_plus (rh, cname);
1252             scratch_start = scratch_off;
1253             if (GNUNET_OK !=
1254                 GNUNET_DNSPARSER_builder_add_name (scratch,
1255                                                    sizeof (scratch),
1256                                                    &scratch_off,
1257                                                    cname))
1258             {
1259               GNUNET_break (0);
1260             }
1261             else
1262             {
1263               rd_new[rd_off].data = &scratch[scratch_start];
1264               rd_new[rd_off].data_size = scratch_off - scratch_start;
1265               rd_off++;
1266             }
1267           }
1268           GNUNET_free_non_null (cname);
1269         }
1270         break;
1271       case GNUNET_DNSPARSER_TYPE_SOA:
1272         {
1273           struct GNUNET_DNSPARSER_SoaRecord *soa;
1274
1275           off = 0;
1276           soa = GNUNET_DNSPARSER_parse_soa (rd[i].data,
1277                                             rd[i].data_size,
1278                                             &off);
1279           if ( (NULL == soa) ||
1280                (off != rd[i].data_size) )
1281           {
1282             GNUNET_break_op (0); /* record not well-formed */
1283           }
1284           else
1285           {
1286             soa->mname = translate_dot_plus (rh, soa->mname);
1287             soa->rname = translate_dot_plus (rh, soa->rname);
1288             scratch_start = scratch_off;
1289             if (GNUNET_OK !=
1290                 GNUNET_DNSPARSER_builder_add_soa (scratch,
1291                                                   sizeof (scratch),
1292                                                   &scratch_off,
1293                                                   soa))
1294             {
1295               GNUNET_break (0);
1296             }
1297             else
1298             {
1299               rd_new[rd_off].data = &scratch[scratch_start];
1300               rd_new[rd_off].data_size = scratch_off - scratch_start;
1301               rd_off++;
1302             }
1303           }
1304           if (NULL != soa)
1305             GNUNET_DNSPARSER_free_soa (soa);
1306         }
1307         break;
1308       case GNUNET_DNSPARSER_TYPE_MX:
1309         {
1310           struct GNUNET_DNSPARSER_MxRecord *mx;
1311
1312           off = 0;
1313           mx = GNUNET_DNSPARSER_parse_mx (rd[i].data,
1314                                           rd[i].data_size,
1315                                           &off);
1316           if ( (NULL == mx) ||
1317                (off != rd[i].data_size) )
1318           {
1319             GNUNET_break_op (0); /* record not well-formed */
1320           }
1321           else
1322           {
1323             mx->mxhost = translate_dot_plus (rh, mx->mxhost);
1324             scratch_start = scratch_off;
1325             if (GNUNET_OK !=
1326                 GNUNET_DNSPARSER_builder_add_mx (scratch,
1327                                                  sizeof (scratch),
1328                                                  &scratch_off,
1329                                                  mx))
1330             {
1331               GNUNET_break (0);
1332             }
1333             else
1334             {
1335               rd_new[rd_off].data = &scratch[scratch_start];
1336               rd_new[rd_off].data_size = scratch_off - scratch_start;
1337               rd_off++;
1338             }
1339           }
1340           if (NULL != mx)
1341             GNUNET_DNSPARSER_free_mx (mx);
1342         }
1343         break;
1344       case GNUNET_DNSPARSER_TYPE_SRV:
1345         {
1346           struct GNUNET_DNSPARSER_SrvRecord *srv;
1347
1348           off = 0;
1349           /* FIXME: passing rh->name here is is not necessarily what we want
1350              (SRV support not finished) */
1351           srv = GNUNET_DNSPARSER_parse_srv (rh->name,
1352                                             rd[i].data,
1353                                             rd[i].data_size,
1354                                             &off);
1355           if ( (NULL == srv) ||
1356                (off != rd[i].data_size) )
1357           {
1358             GNUNET_break_op (0); /* record not well-formed */
1359           }
1360           else
1361           {
1362             srv->domain_name = translate_dot_plus (rh, srv->domain_name);
1363             srv->target = translate_dot_plus (rh, srv->target);
1364             scratch_start = scratch_off;
1365             if (GNUNET_OK !=
1366                 GNUNET_DNSPARSER_builder_add_srv (scratch,
1367                                                   sizeof (scratch),
1368                                                   &scratch_off,
1369                                                   srv))
1370             {
1371               GNUNET_break (0);
1372             }
1373             else
1374             {
1375               rd_new[rd_off].data = &scratch[scratch_start];
1376               rd_new[rd_off].data_size = scratch_off - scratch_start;
1377               rd_off++;
1378             }
1379           }
1380           if (NULL != srv)
1381             GNUNET_DNSPARSER_free_srv (srv);
1382         }
1383         break;
1384       case GNUNET_NAMESTORE_TYPE_PKEY:
1385         /* tigger shortening */
1386         if (NULL != rh->shorten_key)
1387         {
1388           struct GNUNET_CRYPTO_EccPublicSignKey pub;
1389
1390           if (rd[i].data_size != sizeof (struct GNUNET_CRYPTO_EccPublicSignKey))
1391           {
1392             GNUNET_break_op (0);
1393             break;
1394           }
1395           memcpy (&pub, rd[i].data, rd[i].data_size);
1396           GNS_shorten_start (rh->ac_tail->label,
1397                              &pub,
1398                              rh->shorten_key);
1399         }
1400         rd_off++;
1401         break;
1402       default:
1403         rd_off++;
1404         break;
1405       }
1406     }
1407
1408     /* yes, we are done, return result */
1409     rh->proc (rh->proc_cls, rd_off, rd_new);
1410     GNS_resolver_lookup_cancel (rh);
1411     return;
1412   }
1413  do_recurse:
1414   /* need to recurse, check if we can */
1415   for (i=0;i<rd_count;i++)
1416   {
1417     switch (rd[i].record_type)
1418     {
1419     case GNUNET_NAMESTORE_TYPE_PKEY:
1420       /* delegation to another zone */
1421       if (sizeof (struct GNUNET_CRYPTO_EccPublicSignKey) !=
1422           rd[i].data_size)
1423       {
1424         GNUNET_break_op (0);
1425         rh->proc (rh->proc_cls, 0, NULL);
1426         GNS_resolver_lookup_cancel (rh);
1427         return;
1428       }
1429       /* expand authority chain */
1430       ac = GNUNET_new (struct AuthorityChain);
1431       ac->rh = rh;
1432       ac->gns_authority = GNUNET_YES;
1433       memcpy (&ac->authority_info.gns_authority,
1434               rd[i].data,
1435               sizeof (struct GNUNET_CRYPTO_EccPublicSignKey));
1436       ac->label = resolver_lookup_get_next_label (rh);
1437       /* tigger shortening */
1438       if (NULL != rh->shorten_key)
1439         GNS_shorten_start (rh->ac_tail->label,
1440                            &ac->authority_info.gns_authority,
1441                            rh->shorten_key);
1442       /* add AC to tail */
1443       GNUNET_CONTAINER_DLL_insert_tail (rh->ac_head,
1444                                         rh->ac_tail,
1445                                         ac);
1446       /* recurse */
1447       rh->task_id = GNUNET_SCHEDULER_add_now (&recursive_resolution,
1448                                               rh);
1449       return;
1450     case GNUNET_NAMESTORE_TYPE_GNS2DNS:
1451       {
1452         char *ns;
1453         /* resolution continues within DNS */
1454         if (GNUNET_DNSPARSER_MAX_NAME_LENGTH < rd[i].data_size)
1455         {
1456           GNUNET_break_op (0);
1457           rh->proc (rh->proc_cls, 0, NULL);
1458           GNS_resolver_lookup_cancel (rh);
1459           return;
1460         }
1461         /* find associated A/AAAA record */
1462         sa = NULL;
1463         sa_len = 0;
1464         for (j=0;j<rd_count;j++)
1465         {
1466           switch (rd[j].record_type)
1467             {
1468             case GNUNET_DNSPARSER_TYPE_A:
1469               if (sizeof (struct in_addr) != rd[j].data_size)
1470               {
1471                 GNUNET_break_op (0);
1472                 rh->proc (rh->proc_cls, 0, NULL);
1473                 GNS_resolver_lookup_cancel (rh);
1474                 return;
1475               }
1476               /* FIXME: might want to check if we support IPv4 here,
1477                  and otherwise skip this one and hope we find another */
1478               memset (&v4, 0, sizeof (v4));
1479               sa_len = sizeof (v4);
1480               v4.sin_family = AF_INET;
1481               v4.sin_port = htons (53);
1482 #if HAVE_SOCKADDR_IN_SIN_LEN
1483               v4.sin_len = (u_char) sa_len;
1484 #endif
1485               memcpy (&v4.sin_addr,
1486                       rd[j].data,
1487                       sizeof (struct in_addr));
1488               sa = (struct sockaddr *) &v4;
1489               break;
1490             case GNUNET_DNSPARSER_TYPE_AAAA:
1491               if (sizeof (struct in6_addr) != rd[j].data_size)
1492               {
1493                 GNUNET_break_op (0);
1494                 rh->proc (rh->proc_cls, 0, NULL);
1495                 GNS_resolver_lookup_cancel (rh);
1496                 return;
1497               }
1498               /* FIXME: might want to check if we support IPv6 here,
1499                  and otherwise skip this one and hope we find another */
1500               memset (&v6, 0, sizeof (v6));
1501               sa_len = sizeof (v6);
1502               v6.sin6_family = AF_INET6;
1503               v6.sin6_port = htons (53);
1504 #if HAVE_SOCKADDR_IN_SIN_LEN
1505               v6.sin6_len = (u_char) sa_len;
1506 #endif
1507               memcpy (&v6.sin6_addr,
1508                       rd[j].data,
1509                       sizeof (struct in6_addr));
1510               sa = (struct sockaddr *) &v6;
1511               break;
1512             default:
1513               break;
1514             }
1515           if (NULL != sa)
1516             break;
1517         }
1518         if (NULL == sa)
1519         {
1520           /* we cannot continue; NS without A/AAAA */
1521           rh->proc (rh->proc_cls, 0, NULL);
1522           GNS_resolver_lookup_cancel (rh);
1523           return;
1524         }
1525         /* expand authority chain */
1526         ac = GNUNET_new (struct AuthorityChain);
1527         ac->rh = rh;
1528         off = 0;
1529         ns = GNUNET_DNSPARSER_parse_name (rd[i].data,
1530                                           rd[i].data_size,
1531                                           &off);
1532         if ( (NULL == ns) ||
1533              (off != rd[i].data_size) )
1534         {
1535           GNUNET_break_op (0); /* record not well-formed */
1536           rh->proc (rh->proc_cls, 0, NULL);
1537           GNS_resolver_lookup_cancel (rh);
1538           return;
1539         }
1540         strcpy (ac->authority_info.dns_authority.name,
1541                 ns);
1542         memcpy (&ac->authority_info.dns_authority.dns_ip,
1543                 sa,
1544                 sa_len);
1545         /* for DNS recursion, the label is the full DNS name,
1546            created from the remainder of the GNS name and the
1547            name in the NS record */
1548         GNUNET_asprintf (&ac->label,
1549                          "%.*s%s%s",
1550                          (int) rh->name_resolution_pos,
1551                          rh->name,
1552                          (0 != rh->name_resolution_pos) ? "." : "",
1553                          ns);
1554         GNUNET_free (ns);
1555         GNUNET_CONTAINER_DLL_insert_tail (rh->ac_head,
1556                                           rh->ac_tail,
1557                                           ac);
1558         if (strlen (ac->label) > GNUNET_DNSPARSER_MAX_NAME_LENGTH)
1559         {
1560           GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
1561                       _("GNS lookup resulted in DNS name that is too long (`%s')\n"),
1562                       ac->label);
1563           rh->proc (rh->proc_cls, 0, NULL);
1564           GNS_resolver_lookup_cancel (rh);
1565           return;
1566         }
1567         /* recurse */
1568         rh->task_id = GNUNET_SCHEDULER_add_now (&recursive_resolution,
1569                                                 rh);
1570         return;
1571       }
1572     case GNUNET_DNSPARSER_TYPE_CNAME:
1573       {
1574         char *cname;
1575
1576         off = 0;
1577         cname = GNUNET_DNSPARSER_parse_name (rd[i].data,
1578                                              rd[i].data_size,
1579                                              &off);
1580         if ( (NULL == cname) ||
1581              (off != rd[i].data_size) )
1582         {
1583           GNUNET_break_op (0); /* record not well-formed */
1584           rh->proc (rh->proc_cls, 0, NULL);
1585           GNS_resolver_lookup_cancel (rh);
1586           return;
1587         }
1588         handle_gns_cname_result (rh,
1589                                  cname);
1590         GNUNET_free (cname);
1591         return;
1592       }
1593       /* FIXME: handle DNAME */
1594     default:
1595       /* skip */
1596       break;
1597     }
1598   }
1599   GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
1600               _("GNS lookup recursion failed (no delegation record found)\n"));
1601   rh->proc (rh->proc_cls, 0, NULL);
1602   GNS_resolver_lookup_cancel (rh);
1603 }
1604
1605
1606 /**
1607  * Function called once the namestore has completed the request for
1608  * caching a block.
1609  *
1610  * @param cls closure with the 'struct GNS_ResolverHandle'
1611  * @param success #GNUNET_OK on success
1612  * @param emsg error message
1613  */
1614 static void
1615 namestore_cache_continuation (void *cls,
1616                               int32_t success,
1617                               const char *emsg)
1618 {
1619   struct GNS_ResolverHandle *rh = cls;
1620
1621   rh->namestore_qe = NULL;
1622   if (NULL != emsg)
1623     GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
1624                 _("Failed to cache GNS resolution: %s\n"),
1625                 emsg);
1626 }
1627
1628
1629 /**
1630  * Iterator called on each result obtained for a DHT
1631  * operation that expects a reply
1632  *
1633  * @param cls closure with the `struct GNS_ResolverHandle`
1634  * @param exp when will this value expire
1635  * @param key key of the result
1636  * @param get_path peers on reply path (or NULL if not recorded)
1637  *                 [0] = datastore's first neighbor, [length - 1] = local peer
1638  * @param get_path_length number of entries in @a get_path
1639  * @param put_path peers on the PUT path (or NULL if not recorded)
1640  *                 [0] = origin, [length - 1] = datastore
1641  * @param put_path_length number of entries in @a put_path
1642  * @param type type of the result
1643  * @param size number of bytes in data
1644  * @param data pointer to the result data
1645  */
1646 static void
1647 handle_dht_response (void *cls,
1648                      struct GNUNET_TIME_Absolute exp,
1649                      const struct GNUNET_HashCode *key,
1650                      const struct GNUNET_PeerIdentity *get_path,
1651                      unsigned int get_path_length,
1652                      const struct GNUNET_PeerIdentity *put_path,
1653                      unsigned int put_path_length,
1654                      enum GNUNET_BLOCK_Type type,
1655                      size_t size, const void *data)
1656 {
1657   struct GNS_ResolverHandle *rh = cls;
1658   struct AuthorityChain *ac = rh->ac_tail;
1659   const struct GNUNET_NAMESTORE_Block *block;
1660
1661   GNUNET_DHT_get_stop (rh->get_handle);
1662   rh->get_handle = NULL;
1663   GNUNET_CONTAINER_heap_remove_node (rh->dht_heap_node);
1664   rh->dht_heap_node = NULL;
1665   if (size < sizeof (struct GNUNET_NAMESTORE_Block))
1666   {
1667     /* how did this pass DHT block validation!? */
1668     GNUNET_break (0);
1669     rh->proc (rh->proc_cls, 0, NULL);
1670     GNS_resolver_lookup_cancel (rh);
1671     return;
1672   }
1673   block = data;
1674   if (size !=
1675       ntohl (block->purpose.size) +
1676       sizeof (struct GNUNET_CRYPTO_EccPublicSignKey) +
1677       sizeof (struct GNUNET_CRYPTO_EccSignature))
1678   {
1679     /* how did this pass DHT block validation!? */
1680     GNUNET_break (0);
1681     rh->proc (rh->proc_cls, 0, NULL);
1682     GNS_resolver_lookup_cancel (rh);
1683     return;
1684   }
1685   if (GNUNET_OK !=
1686       GNUNET_NAMESTORE_block_decrypt (block,
1687                                       &ac->authority_info.gns_authority,
1688                                       ac->label,
1689                                       &handle_gns_resolution_result,
1690                                       rh))
1691   {
1692     GNUNET_break_op (0); /* block was ill-formed */
1693     rh->proc (rh->proc_cls, 0, NULL);
1694     GNS_resolver_lookup_cancel (rh);
1695     return;
1696   }
1697   /* Cache well-formed blocks */
1698   rh->namestore_qe = GNUNET_NAMESTORE_block_cache (namestore_handle,
1699                                                    block,
1700                                                    &namestore_cache_continuation,
1701                                                    rh);
1702 }
1703
1704
1705 /**
1706  * Process a record that was stored in the namestore.
1707  *
1708  * @param cls closure with the `struct GNS_ResolverHandle`
1709  * @param block block that was stored in the namestore
1710  */
1711 static void
1712 handle_namestore_block_response (void *cls,
1713                                  const struct GNUNET_NAMESTORE_Block *block)
1714 {
1715   struct GNS_ResolverHandle *rh = cls;
1716   struct GNS_ResolverHandle *rx;
1717   struct AuthorityChain *ac = rh->ac_tail;
1718   const char *label = ac->label;
1719   const struct GNUNET_CRYPTO_EccPublicSignKey *auth = &ac->authority_info.gns_authority;
1720   struct GNUNET_HashCode query;
1721
1722   GNUNET_NAMESTORE_query_from_public_key (auth,
1723                                           label,
1724                                           &query);
1725   rh->namestore_qe = NULL;
1726   if ( (GNUNET_NO == rh->only_cached) &&
1727        ( (NULL == block) ||
1728          (0 == GNUNET_TIME_absolute_get_remaining (GNUNET_TIME_absolute_ntoh (block->expiration_time)).rel_value_us) ) )
1729   {
1730     /* Namestore knows nothing; try DHT lookup */
1731     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1732                 "Starting DHT lookup for `%s' in zone %s\n",
1733                 ac->label,
1734                 GNUNET_NAMESTORE_z2s (&ac->authority_info.gns_authority));
1735     rh->get_handle = GNUNET_DHT_get_start (dht_handle,
1736                                            GNUNET_BLOCK_TYPE_GNS_NAMERECORD,
1737                                            &query,
1738                                            DHT_GNS_REPLICATION_LEVEL,
1739                                            GNUNET_DHT_RO_DEMULTIPLEX_EVERYWHERE,
1740                                            NULL, 0,
1741                                            &handle_dht_response, rh);
1742     rh->dht_heap_node = GNUNET_CONTAINER_heap_insert (dht_lookup_heap,
1743                                                       rh,
1744                                                       GNUNET_TIME_absolute_get ().abs_value_us);
1745     if (GNUNET_CONTAINER_heap_get_size (dht_lookup_heap) > max_allowed_background_queries)
1746     {
1747       /* fail longest-standing DHT request */
1748       rx = GNUNET_CONTAINER_heap_peek (dht_lookup_heap);
1749       GNUNET_assert (NULL != rx);
1750       rx->proc (rx->proc_cls, 0, NULL);
1751       GNS_resolver_lookup_cancel (rx);
1752     }
1753     return;
1754   }
1755   if ( (NULL == block) ||
1756        (0 == GNUNET_TIME_absolute_get_remaining (GNUNET_TIME_absolute_ntoh (block->expiration_time)).rel_value_us) )
1757   {
1758     /* DHT not permitted and no local result, fail */
1759     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1760                 "Resolution failed for `%s' in zone %s (DHT lookup not permitted by configuration)\n",
1761                 ac->label,
1762                 GNUNET_NAMESTORE_z2s (&ac->authority_info.gns_authority));
1763     rh->proc (rh->proc_cls, 0, NULL);
1764     GNS_resolver_lookup_cancel (rh);
1765     return;
1766   }
1767   if (GNUNET_OK !=
1768       GNUNET_NAMESTORE_block_decrypt (block,
1769                                       auth,
1770                                       label,
1771                                       &handle_gns_resolution_result,
1772                                       rh))
1773   {
1774     GNUNET_break_op (0); /* block was ill-formed */
1775     rh->proc (rh->proc_cls, 0, NULL);
1776     GNS_resolver_lookup_cancel (rh);
1777     return;
1778   }
1779 }
1780
1781
1782 /**
1783  * Lookup tail of our authority chain in the namestore.
1784  *
1785  * @param rh query we are processing
1786  */
1787 static void
1788 recursive_gns_resolution_namestore (struct GNS_ResolverHandle *rh)
1789 {
1790   struct AuthorityChain *ac = rh->ac_tail;
1791   struct GNUNET_HashCode query;
1792
1793   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1794               "Starting GNS resolution for `%s' in zone %s\n",
1795               ac->label,
1796               GNUNET_NAMESTORE_z2s (&ac->authority_info.gns_authority));
1797   GNUNET_NAMESTORE_query_from_public_key (&ac->authority_info.gns_authority,
1798                                           ac->label,
1799                                           &query);
1800   rh->namestore_qe = GNUNET_NAMESTORE_lookup_block (namestore_handle,
1801                                                     &query,
1802                                                     &handle_namestore_block_response,
1803                                                     rh);
1804 }
1805
1806
1807 /**
1808  * Task scheduled to continue with the resolution process.
1809  *
1810  * @param cls the `struct GNS_ResolverHandle` of the resolution
1811  * @param tc task context
1812  */
1813 static void
1814 recursive_resolution (void *cls,
1815                       const struct GNUNET_SCHEDULER_TaskContext *tc)
1816 {
1817   struct GNS_ResolverHandle *rh = cls;
1818
1819   rh->task_id = GNUNET_SCHEDULER_NO_TASK;
1820   if (MAX_RECURSION < rh->loop_limiter++)
1821   {
1822     GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
1823                 "Encountered unbounded recursion resolving `%s'\n",
1824                 rh->name);
1825     rh->proc (rh->proc_cls, 0, NULL);
1826     GNS_resolver_lookup_cancel (rh);
1827     return;
1828   }
1829   if (GNUNET_YES == rh->ac_tail->gns_authority)
1830     recursive_gns_resolution_namestore (rh);
1831   else
1832     recursive_dns_resolution (rh);
1833 }
1834
1835
1836 /**
1837  * Begin the resolution process from 'name', starting with
1838  * the identification of the zone specified by 'name'.
1839  *
1840  * @param rh resolution to perform
1841  */
1842 static void
1843 start_resolver_lookup (struct GNS_ResolverHandle *rh)
1844 {
1845   struct AuthorityChain *ac;
1846   char *x;
1847   char *y;
1848   char *pkey;
1849
1850   if ( ( (GNUNET_YES == is_canonical (rh->name)) &&
1851          (0 != strcmp (GNUNET_GNS_TLD, rh->name)) ) ||
1852        ( (GNUNET_YES != is_gnu_tld (rh->name)) &&
1853          (GNUNET_YES != is_zkey_tld (rh->name)) ) )
1854   {
1855     /* use standard DNS lookup */
1856     int af;
1857
1858     switch (rh->record_type)
1859     {
1860     case GNUNET_DNSPARSER_TYPE_A:
1861       af = AF_INET;
1862       break;
1863     case GNUNET_DNSPARSER_TYPE_AAAA:
1864       af = AF_INET6;
1865       break;
1866     default:
1867       af = AF_UNSPEC;
1868       break;
1869     }
1870     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1871                 "Doing standard DNS lookup for `%s'\n",
1872                 rh->name);
1873     rh->std_resolve = GNUNET_RESOLVER_ip_get (rh->name,
1874                                               af,
1875                                               DNS_LOOKUP_TIMEOUT,
1876                                               &handle_dns_result,
1877                                               rh);
1878     return;
1879   }
1880   if (is_zkey_tld (rh->name))
1881   {
1882     /* Name ends with ".zkey", try to replace authority zone with zkey
1883        authority */
1884     GNUNET_free (resolver_lookup_get_next_label (rh)); /* will return "zkey" */
1885     x = resolver_lookup_get_next_label (rh); /* will return 'x' coordinate */
1886     y = resolver_lookup_get_next_label (rh); /* will return 'y' coordinate */
1887     GNUNET_asprintf (&pkey,
1888                      "%s%s",
1889                      x, y);
1890     if ( (NULL == x) ||
1891          (NULL == y) ||
1892          (GNUNET_OK !=
1893           GNUNET_CRYPTO_ecc_public_sign_key_from_string (pkey,
1894                                                     strlen (pkey),
1895                                                     &rh->authority_zone)) )
1896     {
1897       GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
1898                   _("Hostname `%s' is not well-formed, resolution fails\n"),
1899                   rh->name);
1900       rh->task_id = GNUNET_SCHEDULER_add_now (&fail_resolution, rh);
1901     }
1902     GNUNET_free_non_null (x);
1903     GNUNET_free_non_null (y);
1904     GNUNET_free (pkey);
1905   }
1906   else
1907   {
1908     /* Name ends with ".gnu", eat ".gnu" and continue with resolution */
1909     GNUNET_free (resolver_lookup_get_next_label (rh));
1910   }
1911   ac = GNUNET_new (struct AuthorityChain);
1912   ac->rh = rh;
1913   ac->label = resolver_lookup_get_next_label (rh);
1914   if (NULL == ac->label)
1915     /* name was just "gnu", so we default to label '+' */
1916     ac->label = GNUNET_strdup (GNUNET_GNS_MASTERZONE_STR);
1917   ac->gns_authority = GNUNET_YES;
1918   ac->authority_info.gns_authority = rh->authority_zone;
1919   GNUNET_CONTAINER_DLL_insert_tail (rh->ac_head,
1920                                     rh->ac_tail,
1921                                     ac);
1922   rh->task_id = GNUNET_SCHEDULER_add_now (&recursive_resolution,
1923                                           rh);
1924 }
1925
1926
1927 /**
1928  * Lookup of a record in a specific zone calls lookup result processor
1929  * on result.
1930  *
1931  * @param zone the zone to perform the lookup in
1932  * @param record_type the record type to look up
1933  * @param name the name to look up
1934  * @param shorten_key a private key for use with PSEU import (can be NULL)
1935  * @param only_cached #GNUNET_NO to only check locally not DHT for performance
1936  * @param proc the processor to call on result
1937  * @param proc_cls the closure to pass to @a proc
1938  * @return handle to cancel operation
1939  */
1940 struct GNS_ResolverHandle *
1941 GNS_resolver_lookup (const struct GNUNET_CRYPTO_EccPublicSignKey *zone,
1942                      uint32_t record_type,
1943                      const char *name,
1944                      const struct GNUNET_CRYPTO_EccPrivateKey *shorten_key,
1945                      int only_cached,
1946                      GNS_ResultProcessor proc, void *proc_cls)
1947 {
1948   struct GNS_ResolverHandle *rh;
1949
1950   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1951               "Starting lookup for `%s'\n",
1952               name);
1953   rh = GNUNET_new (struct GNS_ResolverHandle);
1954   GNUNET_CONTAINER_DLL_insert (rlh_head,
1955                                rlh_tail,
1956                                rh);
1957   rh->authority_zone = *zone;
1958   rh->proc = proc;
1959   rh->proc_cls = proc_cls;
1960   rh->only_cached = only_cached;
1961   rh->record_type = record_type;
1962   rh->name = GNUNET_strdup (name);
1963   rh->name_resolution_pos = strlen (name);
1964   if (NULL != shorten_key)
1965   {
1966     rh->shorten_key = GNUNET_new (struct GNUNET_CRYPTO_EccPrivateKey);
1967     *rh->shorten_key = *shorten_key;
1968   }
1969   start_resolver_lookup (rh);
1970   return rh;
1971 }
1972
1973
1974 /**
1975  * Cancel active resolution (i.e. client disconnected).
1976  *
1977  * @param rh resolution to abort
1978  */
1979 void
1980 GNS_resolver_lookup_cancel (struct GNS_ResolverHandle *rh)
1981 {
1982   struct DnsResult *dr;
1983   struct AuthorityChain *ac;
1984   struct VpnContext *vpn_ctx;
1985
1986   GNUNET_CONTAINER_DLL_remove (rlh_head,
1987                                rlh_tail,
1988                                rh);
1989   while (NULL != (ac = rh->ac_head))
1990   {
1991     GNUNET_CONTAINER_DLL_remove (rh->ac_head,
1992                                  rh->ac_tail,
1993                                  ac);
1994     GNUNET_free (ac->label);
1995     GNUNET_free (ac);
1996   }
1997   if (GNUNET_SCHEDULER_NO_TASK != rh->task_id)
1998   {
1999     GNUNET_SCHEDULER_cancel (rh->task_id);
2000     rh->task_id = GNUNET_SCHEDULER_NO_TASK;
2001   }
2002   if (NULL != rh->get_handle)
2003   {
2004     GNUNET_DHT_get_stop (rh->get_handle);
2005     rh->get_handle = NULL;
2006   }
2007   if (NULL != rh->dht_heap_node)
2008   {
2009     GNUNET_CONTAINER_heap_remove_node (rh->dht_heap_node);
2010     rh->dht_heap_node = NULL;
2011   }
2012   if (NULL != (vpn_ctx = rh->vpn_ctx))
2013   {
2014     GNUNET_VPN_cancel_request (vpn_ctx->vpn_request);
2015     GNUNET_free (vpn_ctx->rd_data);
2016     GNUNET_free (vpn_ctx);
2017   }
2018   if (NULL != rh->dns_request)
2019   {
2020     GNUNET_DNSSTUB_resolve_cancel (rh->dns_request);
2021     rh->dns_request = NULL;
2022   }
2023   if (NULL != rh->namestore_qe)
2024   {
2025     GNUNET_NAMESTORE_cancel (rh->namestore_qe);
2026     rh->namestore_qe = NULL;
2027   }
2028   if (NULL != rh->std_resolve)
2029   {
2030     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
2031                 "Canceling standard DNS resolution\n");
2032     GNUNET_RESOLVER_request_cancel (rh->std_resolve);
2033     rh->std_resolve = NULL;
2034   }
2035   while (NULL != (dr = rh->dns_result_head))
2036   {
2037     GNUNET_CONTAINER_DLL_remove (rh->dns_result_head,
2038                                  rh->dns_result_tail,
2039                                  dr);
2040     GNUNET_free (dr);
2041   }
2042   GNUNET_free_non_null (rh->shorten_key);
2043   GNUNET_free (rh->name);
2044   GNUNET_free (rh);
2045 }
2046
2047
2048 /* ***************** Resolver initialization ********************* */
2049
2050
2051 /**
2052  * Initialize the resolver
2053  *
2054  * @param nh the namestore handle
2055  * @param dht the dht handle
2056  * @param c configuration handle
2057  * @param max_bg_queries maximum number of parallel background queries in dht
2058  */
2059 void
2060 GNS_resolver_init (struct GNUNET_NAMESTORE_Handle *nh,
2061                    struct GNUNET_DHT_Handle *dht,
2062                    const struct GNUNET_CONFIGURATION_Handle *c,
2063                    unsigned long long max_bg_queries)
2064 {
2065   char *dns_ip;
2066
2067   cfg = c;
2068   namestore_handle = nh;
2069   dht_handle = dht;
2070   dht_lookup_heap =
2071     GNUNET_CONTAINER_heap_create (GNUNET_CONTAINER_HEAP_ORDER_MIN);
2072   max_allowed_background_queries = max_bg_queries;
2073   if (GNUNET_OK !=
2074       GNUNET_CONFIGURATION_get_value_string (c,
2075                                              "gns",
2076                                              "DNS_RESOLVER",
2077                                              &dns_ip))
2078   {
2079     /* user did not specify DNS resolver, use 8.8.8.8 */
2080     dns_ip = GNUNET_strdup ("8.8.8.8");
2081   }
2082   dns_handle = GNUNET_DNSSTUB_start (dns_ip);
2083   GNUNET_free (dns_ip);
2084   vpn_handle = GNUNET_VPN_connect (cfg);
2085 }
2086
2087
2088 /**
2089  * Shutdown resolver
2090  */
2091 void
2092 GNS_resolver_done ()
2093 {
2094   struct GNS_ResolverHandle *rh;
2095
2096   /* abort active resolutions */
2097   while (NULL != (rh = rlh_head))
2098   {
2099     rh->proc (rh->proc_cls, 0, NULL);
2100     GNS_resolver_lookup_cancel (rh);
2101   }
2102   GNUNET_CONTAINER_heap_destroy (dht_lookup_heap);
2103   dht_lookup_heap = NULL;
2104   GNUNET_DNSSTUB_stop (dns_handle);
2105   dns_handle = NULL;
2106   GNUNET_VPN_disconnect (vpn_handle);
2107   vpn_handle = NULL;
2108   dht_handle = NULL;
2109   namestore_handle = NULL;
2110 }
2111
2112
2113 /* *************** common helper functions (do not really belong here) *********** */
2114
2115 /**
2116  * Checks if @a name ends in ".TLD"
2117  *
2118  * @param name the name to check
2119  * @param tld the TLD to check for
2120  * @return GNUNET_YES or GNUNET_NO
2121  */
2122 int
2123 is_tld (const char* name, const char* tld)
2124 {
2125   size_t offset = 0;
2126
2127   if (strlen (name) <= strlen (tld))
2128     return GNUNET_NO;
2129   offset = strlen (name) - strlen (tld);
2130   if (0 != strcmp (name + offset, tld))
2131     return GNUNET_NO;
2132   return GNUNET_YES;
2133 }
2134
2135
2136 /* end of gnunet-service-gns_resolver.c */