src/gns/gnunet-service-gns_resolver.c

   1 /*
   2      This file is part of GNUnet.
   3      Copyright (C) 2011-2013 GNUnet e.V.
   4
   5      GNUnet is free software: you can redistribute it and/or modify it
   6      under the terms of the GNU Affero General Public License as published
   7      by the Free Software Foundation, either version 3 of the License,
   8      or (at your 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      Affero General Public License for more details.
  14
  15      You should have received a copy of the GNU Affero General Public License
  16      along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17
  18      SPDX-License-Identifier: AGPL3.0-or-later
  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 #include "platform.h"
  28 #include "gnunet_util_lib.h"
  29 #include "gnunet_dnsstub_lib.h"
  30 #include "gnunet_dht_service.h"
  31 #include "gnunet_gnsrecord_lib.h"
  32 #include "gnunet_namecache_service.h"
  33 #include "gnunet_dns_service.h"
  34 #include "gnunet_resolver_service.h"
  35 #include "gnunet_revocation_service.h"
  36 #include "gnunet_dnsparser_lib.h"
  37 #include "gnunet_tun_lib.h"
  38 #include "gnunet_gns_service.h"
  39 #include "gns.h"
  40 #include "gnunet-service-gns.h"
  41 #include "gnunet-service-gns_resolver.h"
  42 #include "gnunet_vpn_service.h"
  43
  44
  45 /**
  46  * Default DHT timeout for lookups.
  47  */
  48 #define DHT_LOOKUP_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 60)
  49
  50 /**
  51  * Default timeout for DNS lookups.
  52  */
  53 #define DNS_LOOKUP_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 15)
  54
  55 /**
  56  * Default timeout for VPN redirections.
  57  */
  58 #define VPN_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MINUTES, 30)
  59
  60 /**
  61  * DHT replication level
  62  */
  63 #define DHT_GNS_REPLICATION_LEVEL 10
  64
  65 /**
  66  * How deep do we allow recursions to go before we abort?
  67  */
  68 #define MAX_RECURSION 256
  69
  70
  71 /**
  72  * DLL to hold the authority chain we had to pass in the resolution
  73  * process.
  74  */
  75 struct AuthorityChain;
  76
  77
  78 /**
  79  * Element of a resolution process for looking up the
  80  * responsible DNS server hostname in a GNS2DNS recursive
  81  * resolution.
  82  */
  83 struct Gns2DnsPending
  84 {
  85
  86   /**
  87    * Kept in a DLL.
  88    */
  89   struct Gns2DnsPending *next;
  90
  91   /**
  92    * Kept in a DLL.
  93    */
  94   struct Gns2DnsPending *prev;
  95
  96   /**
  97    * Context this activity belongs with.
  98    */
  99   struct AuthorityChain *ac;
 100
 101   /**
 102    * Handle for the resolution of the IP part of the
 103    * GNS2DNS record.  Will return to us the addresses
 104    * of the DNS resolver to use.
 105    */
 106   struct GNS_ResolverHandle *rh;
 107
 108   /**
 109    * Handle for DNS resolution of the DNS nameserver.
 110    */
 111   struct GNUNET_RESOLVER_RequestHandle *dns_rh;
 112
 113   /**
 114    * How many results did we get?
 115    */
 116   unsigned int num_results;
 117 };
 118
 119
 120 /**
 121  * Handle to a currenty pending resolution.  On result (positive or
 122  * negative) the #GNS_ResultProcessor is called.
 123  */
 124 struct GNS_ResolverHandle;
 125
 126
 127 /**
 128  * DLL to hold the authority chain we had to pass in the resolution
 129  * process.
 130  */
 131 struct AuthorityChain
 132 {
 133   /**
 134    * This is a DLL.
 135    */
 136   struct AuthorityChain *prev;
 137
 138   /**
 139    * This is a DLL.
 140    */
 141   struct AuthorityChain *next;
 142
 143   /**
 144    * Resolver handle this entry in the chain belongs to.
 145    */
 146   struct GNS_ResolverHandle *rh;
 147
 148   /**
 149    * label/name corresponding to the authority
 150    */
 151   char *label;
 152
 153   /**
 154    * #GNUNET_YES if the authority was a GNS authority,
 155    * #GNUNET_NO if the authority was a DNS authority.
 156    */
 157   int gns_authority;
 158
 159   /**
 160    * Information about the resolver authority for this label.
 161    */
 162   union
 163   {
 164
 165     /**
 166      * The zone of the GNS authority
 167      */
 168     struct GNUNET_CRYPTO_EcdsaPublicKey gns_authority;
 169
 170     struct
 171     {
 172       /**
 173        * Domain of the DNS resolver that is the authority.
 174        * (appended to construct the DNS name to resolve;
 175        * this is NOT the DNS name of the DNS server!).
 176        */
 177       char name[GNUNET_DNSPARSER_MAX_NAME_LENGTH + 1];
 178
 179       /**
 180        * List of resolutions of the 'ip' of the name server that
 181        * are still pending.
 182        */
 183       struct Gns2DnsPending *gp_head;
 184
 185       /**
 186        * Tail of list of resolutions of the 'ip' of the name server that
 187        * are still pending.
 188        */
 189       struct Gns2DnsPending *gp_tail;
 190
 191       /**
 192        * Handle to perform DNS lookups with this authority (in GNS2DNS handling).
 193        */
 194       struct GNUNET_DNSSTUB_Context *dns_handle;
 195
 196       /**
 197        * Did we succeed in getting an IP address for *any* of the DNS servers listed?
 198        * Once we do, we can start with DNS queries.
 199        */
 200       int found;
 201
 202       /**
 203        * Did we start the recursive resolution via DNS?
 204        */
 205       int launched;
 206
 207     } dns_authority;
 208
 209   } authority_info;
 210
 211 };
 212
 213
 214 /**
 215  * A result we got from DNS.
 216  */
 217 struct DnsResult
 218 {
 219
 220   /**
 221    * Kept in DLL.
 222    */
 223   struct DnsResult *next;
 224
 225   /**
 226    * Kept in DLL.
 227    */
 228   struct DnsResult *prev;
 229
 230   /**
 231    * Binary value stored in the DNS record (appended to this struct)
 232    */
 233   const void *data;
 234
 235   /**
 236    * Expiration time for the DNS record, 0 if we didn't
 237    * get anything useful (i.e. 'gethostbyname()' was used).
 238    */
 239   uint64_t expiration_time;
 240
 241   /**
 242    * Number of bytes in @e data.
 243    */
 244   size_t data_size;
 245
 246   /**
 247    * Type of the GNS/DNS record.
 248    */
 249   uint32_t record_type;
 250
 251 };
 252
 253
 254 /**
 255  * Closure for #vpn_allocation_cb.
 256  */
 257 struct VpnContext
 258 {
 259
 260   /**
 261    * Which resolution process are we processing.
 262    */
 263   struct GNS_ResolverHandle *rh;
 264
 265   /**
 266    * Handle to the VPN request that we were performing.
 267    */
 268   struct GNUNET_VPN_RedirectionRequest *vpn_request;
 269
 270   /**
 271    * Number of records serialized in @e rd_data.
 272    */
 273   unsigned int rd_count;
 274
 275   /**
 276    * Serialized records.
 277    */
 278   char *rd_data;
 279
 280   /**
 281    * Number of bytes in @e rd_data.
 282    */
 283   ssize_t rd_data_size;
 284 };
 285
 286
 287 /**
 288  * Handle to a currenty pending resolution.  On result (positive or
 289  * negative) the #GNS_ResultProcessor is called.
 290  */
 291 struct GNS_ResolverHandle
 292 {
 293
 294   /**
 295    * DLL
 296    */
 297   struct GNS_ResolverHandle *next;
 298
 299   /**
 300    * DLL
 301    */
 302   struct GNS_ResolverHandle *prev;
 303
 304   /**
 305    * The top-level GNS authoritative zone to query
 306    */
 307   struct GNUNET_CRYPTO_EcdsaPublicKey authority_zone;
 308
 309   /**
 310    * called when resolution phase finishes
 311    */
 312   GNS_ResultProcessor proc;
 313
 314   /**
 315    * closure passed to @e proc
 316    */
 317   void* proc_cls;
 318
 319   /**
 320    * Handle for DHT lookups. should be NULL if no lookups are in progress
 321    */
 322   struct GNUNET_DHT_GetHandle *get_handle;
 323
 324   /**
 325    * Handle to a VPN request, NULL if none is active.
 326    */
 327   struct VpnContext *vpn_ctx;
 328
 329   /**
 330    * Socket for a DNS request, NULL if none is active.
 331    */
 332   struct GNUNET_DNSSTUB_RequestSocket *dns_request;
 333
 334   /**
 335    * Handle for standard DNS resolution, NULL if none is active.
 336    */
 337   struct GNUNET_RESOLVER_RequestHandle *std_resolve;
 338
 339   /**
 340    * Pending Namecache lookup task
 341    */
 342   struct GNUNET_NAMECACHE_QueueEntry *namecache_qe;
 343
 344   /**
 345    * Pending revocation check.
 346    */
 347   struct GNUNET_REVOCATION_Query *rev_check;
 348
 349   /**
 350    * Heap node associated with this lookup.  Used to limit number of
 351    * concurrent requests.
 352    */
 353   struct GNUNET_CONTAINER_HeapNode *dht_heap_node;
 354
 355   /**
 356    * DLL to store the authority chain
 357    */
 358   struct AuthorityChain *ac_head;
 359
 360   /**
 361    * DLL to store the authority chain
 362    */
 363   struct AuthorityChain *ac_tail;
 364
 365   /**
 366    * ID of a task associated with the resolution process.
 367    */
 368   struct GNUNET_SCHEDULER_Task *task_id;
 369
 370   /**
 371    * The name to resolve
 372    */
 373   char *name;
 374
 375   /**
 376    * Legacy Hostname to use if we encountered GNS2DNS record
 377    * and thus can deduct the LEHO from that transition.
 378    */
 379   char *leho;
 380
 381   /**
 382    * DLL of results we got from DNS.
 383    */
 384   struct DnsResult *dns_result_head;
 385
 386   /**
 387    * DLL of results we got from DNS.
 388    */
 389   struct DnsResult *dns_result_tail;
 390
 391   /**
 392    * Current offset in 'name' where we are resolving.
 393    */
 394   size_t name_resolution_pos;
 395
 396   /**
 397    * Use only cache
 398    */
 399   enum GNUNET_GNS_LocalOptions options;
 400
 401   /**
 402    * For SRV and TLSA records, the number of the
 403    * protocol specified in the name.  0 if no protocol was given.
 404    */
 405   int protocol;
 406
 407   /**
 408    * For SRV and TLSA records, the number of the
 409    * service specified in the name.  0 if no service was given.
 410    */
 411   int service;
 412
 413   /**
 414    * Desired type for the resolution.
 415    */
 416   int record_type;
 417
 418   /**
 419    * We increment the loop limiter for each step in a recursive
 420    * resolution.  If it passes our threshold (i.e. due to
 421    * self-recursion in the resolution, i.e CNAME fun), we stop.
 422    */
 423   unsigned int loop_limiter;
 424
 425   /**
 426    * 16 bit random ID we used in the @e dns_request.
 427    */
 428   uint16_t original_dns_id;
 429
 430 };
 431
 432
 433 /**
 434  * Active namestore caching operations.
 435  */
 436 struct CacheOps
 437 {
 438
 439   /**
 440    * Organized in a DLL.
 441    */
 442   struct CacheOps *next;
 443
 444   /**
 445    * Organized in a DLL.
 446    */
 447   struct CacheOps *prev;
 448
 449   /**
 450    * Pending Namestore caching task.
 451    */
 452   struct GNUNET_NAMECACHE_QueueEntry *namecache_qe_cache;
 453
 454 };
 455
 456
 457 /**
 458  * Our handle to the namecache service
 459  */
 460 static struct GNUNET_NAMECACHE_Handle *namecache_handle;
 461
 462 /**
 463  * Our handle to the vpn service
 464  */
 465 static struct GNUNET_VPN_Handle *vpn_handle;
 466
 467 /**
 468  * Resolver handle to the dht
 469  */
 470 static struct GNUNET_DHT_Handle *dht_handle;
 471
 472 /**
 473  * Heap for limiting parallel DHT lookups
 474  */
 475 static struct GNUNET_CONTAINER_Heap *dht_lookup_heap;
 476
 477 /**
 478  * Maximum amount of parallel queries to the DHT
 479  */
 480 static unsigned long long max_allowed_background_queries;
 481
 482 /**
 483  * Head of resolver lookup list
 484  */
 485 static struct GNS_ResolverHandle *rlh_head;
 486
 487 /**
 488  * Tail of resolver lookup list
 489  */
 490 static struct GNS_ResolverHandle *rlh_tail;
 491
 492 /**
 493  * Organized in a DLL.
 494  */
 495 static struct CacheOps *co_head;
 496
 497 /**
 498  * Organized in a DLL.
 499  */
 500 static struct CacheOps *co_tail;
 501
 502 /**
 503  * Use namecache
 504  */
 505 static int disable_cache;
 506
 507 /**
 508  * Global configuration.
 509  */
 510 static const struct GNUNET_CONFIGURATION_Handle *cfg;
 511
 512
 513 /**
 514  * Determine if this name is canonical (is a legal name in a zone, without delegation);
 515  * note that we do not test that the name does not contain illegal characters, we only
 516  * test for delegation.  Note that service records (i.e. _foo._srv) are canonical names
 517  * even though they consist of multiple labels.
 518  *
 519  * Examples:
 520  * a.b.gnu   = not canonical
 521  * a         = canonical
 522  * _foo._srv = canonical
 523  * _f.bar    = not canonical
 524  *
 525  * @param name the name to test
 526  * @return #GNUNET_YES if canonical
 527  */
 528 /* dead, but keep for now */ int
 529 is_canonical (const char *name)
 530 {
 531   const char *pos;
 532   const char *dot;
 533
 534   if (NULL == strchr (name,
 535                       (unsigned char) '.'))
 536     return GNUNET_YES;
 537   if ('_' != name[0])
 538     return GNUNET_NO;
 539   pos = &name[1];
 540   while (NULL != (dot = strchr (pos,
 541                                 (unsigned char) '.')))
 542     if ('_' != dot[1])
 543       return GNUNET_NO;
 544     else
 545       pos = dot + 1;
 546   return GNUNET_YES;
 547 }
 548
 549 /* ************************** Resolution **************************** */
 550
 551 /**
 552  * Expands a name ending in .+ with the zone of origin.
 553  *
 554  * @param rh resolution context
 555  * @param name name to modify (to be free'd or returned)
 556  * @return updated name
 557  */
 558 static char *
 559 translate_dot_plus (struct GNS_ResolverHandle *rh,
 560                     char *name)
 561 {
 562   char *ret;
 563   size_t s_len = strlen (name);
 564
 565   if (0 != strcmp (&name[s_len - 2],
 566                    ".+"))
 567     return name; /* did not end in ".+" */
 568   GNUNET_assert (GNUNET_YES == rh->ac_tail->gns_authority);
 569   GNUNET_asprintf (&ret,
 570                    "%.*s.%s",
 571                    (int) (s_len - 2),
 572                    name,
 573                    GNUNET_GNSRECORD_pkey_to_zkey (&rh->ac_tail->authority_info.gns_authority));
 574   GNUNET_free (name);
 575   return ret;
 576 }
 577
 578
 579 /**
 580  * Wrapper around #GNS_resolver_lookup_cancel() as a task.
 581  * Used for delayed cleanup so we can unwind the stack first.
 582  *
 583  * @param cls the `struct GNS_ResolverHandle`
 584  */
 585 static void
 586 GNS_resolver_lookup_cancel_ (void *cls)
 587 {
 588   struct GNS_ResolverHandle *rh = cls;
 589
 590   rh->task_id = NULL;
 591   GNS_resolver_lookup_cancel (rh);
 592 }
 593
 594
 595 /**
 596  * Function called to asynchronously fail a resolution.
 597  *
 598  * @param rh the resolution to fail
 599  */
 600 static void
 601 fail_resolution (struct GNS_ResolverHandle *rh)
 602 {
 603   rh->proc (rh->proc_cls,
 604             0,
 605             NULL);
 606   GNUNET_assert (NULL == rh->task_id);
 607   rh->task_id = GNUNET_SCHEDULER_add_now (&GNS_resolver_lookup_cancel_,
 608                                           rh);
 609 }
 610
 611
 612 /**
 613  * Function called when a resolution times out.
 614  *
 615  * @param cls the `struct GNS_ResolverHandle`
 616  */
 617 static void
 618 timeout_resolution (void *cls)
 619 {
 620   struct GNS_ResolverHandle *rh = cls;
 621
 622   rh->task_id = NULL;
 623   fail_resolution (rh);
 624 }
 625
 626
 627 /**
 628  * Get the next, rightmost label from the name that we are trying to resolve,
 629  * and update the resolution position accordingly.  Labels usually consist
 630  * of up to 63 characters without a period ("."); however, we use a special
 631  * convention to support SRV and TLSA records where the domain name
 632  * includes an encoding for a service and protocol in the name.  The
 633  * syntax (see RFC 2782) here is "_Service._Proto.Name" and in this
 634  * special case we include the "_Service._Proto" in the rightmost label.
 635  * Thus, for "_443._tcp.foo.bar" we first return the label "bar" and then
 636  * the label "_443._tcp.foo".  The special case is detected by the
 637  * presence of labels beginning with an underscore.  Whenever a label
 638  * begins with an underscore, it is combined with the label to its right
 639  * (and the "." is preserved).
 640  *
 641  * @param rh handle to the resolution operation to get the next label from
 642  * @return NULL if there are no more labels
 643  */
 644 static char *
 645 resolver_lookup_get_next_label (struct GNS_ResolverHandle *rh)
 646 {
 647   const char *rp;
 648   const char *dot;
 649   size_t len;
 650   char *ret;
 651   char *srv_name;
 652   char *proto_name;
 653   struct protoent *pe;
 654   struct servent *se;
 655
 656   if (0 == rh->name_resolution_pos)
 657     return NULL;
 658   dot = memrchr (rh->name,
 659                  (int) '.',
 660                  rh->name_resolution_pos);
 661   if (NULL == dot)
 662   {
 663     /* done, this was the last one */
 664     len = rh->name_resolution_pos;
 665     rp = rh->name;
 666     rh->name_resolution_pos = 0;
 667   }
 668   else
 669   {
 670     /* advance by one label */
 671     len = rh->name_resolution_pos - (dot - rh->name) - 1;
 672     rp = dot + 1;
 673     rh->name_resolution_pos = dot - rh->name;
 674   }
 675   rh->protocol = 0;
 676   rh->service = 0;
 677   ret = GNUNET_strndup (rp, len);
 678   /* If we have labels starting with underscore with label on
 679    * the right (SRV/DANE/BOX case), determine port/protocol;
 680    * The format of `rh->name` must be "_PORT._PROTOCOL".
 681    */
 682   if ( ('_' == rh->name[0]) &&
 683        (NULL != (dot = memrchr (rh->name,
 684                                 (int) '.',
 685                                 rh->name_resolution_pos))) &&
 686        ('_' == dot[1]) &&
 687        (NULL == memrchr (rh->name,
 688                          (int) '.',
 689                          dot - rh->name)) )
 690   {
 691     srv_name = GNUNET_strndup (&rh->name[1],
 692                                (dot - rh->name) - 1);
 693     proto_name = GNUNET_strndup (&dot[2],
 694                                  rh->name_resolution_pos - (dot - rh->name) - 1);
 695     rh->name_resolution_pos = 0;
 696     pe = getprotobyname (proto_name);
 697     if (NULL == pe)
 698     {
 699       GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
 700                   _("Protocol `%s' unknown, skipping labels.\n"),
 701                   proto_name);
 702       GNUNET_free (proto_name);
 703       GNUNET_free (srv_name);
 704       return ret;
 705     }
 706     se = getservbyname (srv_name,
 707                         proto_name);
 708     if (NULL == se)
 709     {
 710       GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
 711                   _("Service `%s' unknown for protocol `%s', skipping labels.\n"),
 712                   srv_name,
 713                   proto_name);
 714       GNUNET_free (proto_name);
 715       GNUNET_free (srv_name);
 716       return ret;
 717     }
 718     rh->protocol = pe->p_proto;
 719     rh->service = se->s_port;
 720     GNUNET_free (proto_name);
 721     GNUNET_free (srv_name);
 722   }
 723   return ret;
 724 }
 725
 726
 727 /**
 728  * Gives the cummulative result obtained to the callback and clean up the request.
 729  *
 730  * @param rh resolution process that has culminated in a result
 731  */
 732 static void
 733 transmit_lookup_dns_result (struct GNS_ResolverHandle *rh)
 734 {
 735   struct DnsResult *pos;
 736   unsigned int n;
 737   unsigned int i;
 738
 739   n = 0;
 740   for (pos = rh->dns_result_head; NULL != pos; pos = pos->next)
 741     n++;
 742   {
 743     struct GNUNET_GNSRECORD_Data rd[n];
 744
 745     i = 0;
 746     for (pos = rh->dns_result_head; NULL != pos; pos = pos->next)
 747     {
 748       rd[i].data = pos->data;
 749       rd[i].data_size = pos->data_size;
 750       rd[i].record_type = pos->record_type;
 751       if (0 == pos->expiration_time)
 752       {
 753         rd[i].flags = GNUNET_GNSRECORD_RF_RELATIVE_EXPIRATION;
 754         rd[i].expiration_time = 0;
 755       }
 756       else
 757       {
 758         rd[i].flags = GNUNET_GNSRECORD_RF_NONE;
 759         rd[i].expiration_time = pos->expiration_time;
 760       }
 761       i++;
 762     }
 763     GNUNET_assert (i == n);
 764     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 765                 "Transmitting standard DNS result with %u records\n",
 766                 n);
 767     rh->proc (rh->proc_cls,
 768               n,
 769               rd);
 770   }
 771   GNS_resolver_lookup_cancel (rh);
 772 }
 773
 774
 775 /**
 776  * Add a result from DNS to the records to be returned to the application.
 777  *
 778  * @param rh resolution request to extend with a result
 779  * @param expiration_time expiration time for the answer
 780  * @param record_type DNS record type of the answer
 781  * @param data_size number of bytes in @a data
 782  * @param data binary data to return in DNS record
 783  */
 784 static void
 785 add_dns_result (struct GNS_ResolverHandle *rh,
 786                 uint64_t expiration_time,
 787                 uint32_t record_type,
 788                 size_t data_size,
 789                 const void *data)
 790 {
 791   struct DnsResult *res;
 792
 793   res = GNUNET_malloc (sizeof (struct DnsResult) + data_size);
 794   res->expiration_time = expiration_time;
 795   res->data_size = data_size;
 796   res->record_type = record_type;
 797   res->data = &res[1];
 798   GNUNET_memcpy (&res[1],
 799                  data,
 800                  data_size);
 801   GNUNET_CONTAINER_DLL_insert (rh->dns_result_head,
 802                                rh->dns_result_tail,
 803                                res);
 804 }
 805
 806
 807 /**
 808  * We had to do a DNS lookup.  Convert the result (if any) and return
 809  * it.
 810  *
 811  * @param cls closure with the `struct GNS_ResolverHandle`
 812  * @param addr one of the addresses of the host, NULL for the last address
 813  * @param addrlen length of the address
 814  */
 815 static void
 816 handle_dns_result (void *cls,
 817                    const struct sockaddr *addr,
 818                    socklen_t addrlen)
 819 {
 820   struct GNS_ResolverHandle *rh = cls;
 821   const struct sockaddr_in *sa4;
 822   const struct sockaddr_in6 *sa6;
 823
 824   if (NULL == addr)
 825   {
 826     rh->std_resolve = NULL;
 827     transmit_lookup_dns_result (rh);
 828     return;
 829   }
 830   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 831               "Received %u bytes of DNS IP data\n",
 832               addrlen);
 833   switch (addr->sa_family)
 834   {
 835   case AF_INET:
 836     sa4 = (const struct sockaddr_in *) addr;
 837     add_dns_result (rh,
 838                     0 /* expiration time is unknown */,
 839                     GNUNET_DNSPARSER_TYPE_A,
 840                     sizeof (struct in_addr),
 841                     &sa4->sin_addr);
 842     break;
 843   case AF_INET6:
 844     sa6 = (const struct sockaddr_in6 *) addr;
 845     add_dns_result (rh,
 846                     0 /* expiration time is unknown */,
 847                     GNUNET_DNSPARSER_TYPE_AAAA,
 848                     sizeof (struct in6_addr),
 849                     &sa6->sin6_addr);
 850     break;
 851   default:
 852     GNUNET_break (0);
 853     break;
 854   }
 855 }
 856
 857
 858 /**
 859  * Task scheduled to continue with the resolution process.
 860  *
 861  * @param cls the 'struct GNS_ResolverHandle' of the resolution
 862  * @param tc task context
 863  */
 864 static void
 865 recursive_resolution (void *cls);
 866
 867
 868 /**
 869  * Begin the resolution process from 'name', starting with
 870  * the identification of the zone specified by 'name'.
 871  *
 872  * @param cls closure with `struct GNS_ResolverHandle *rh`
 873  */
 874 static void
 875 start_resolver_lookup (void *cls);
 876
 877
 878 /**
 879  * Function called with the result of a DNS resolution.
 880  *
 881  * @param cls the request handle of the resolution that
 882  *        we were attempting to make
 883  * @param dns dns response, never NULL
 884  * @param dns_len number of bytes in @a dns
 885  */
 886 static void
 887 dns_result_parser (void *cls,
 888                    const struct GNUNET_TUN_DnsHeader *dns,
 889                    size_t dns_len)
 890 {
 891   struct GNS_ResolverHandle *rh = cls;
 892   struct GNUNET_DNSPARSER_Packet *p;
 893   const struct GNUNET_DNSPARSER_Record *rec;
 894   unsigned int rd_count;
 895
 896   if (NULL == dns)
 897   {
 898     rh->dns_request = NULL;
 899     GNUNET_SCHEDULER_cancel (rh->task_id);
 900     rh->task_id = NULL;
 901     fail_resolution (rh);
 902     return;
 903   }
 904   if (rh->original_dns_id != dns->id)
 905   {
 906     /* DNS answer, but for another query */
 907     return;
 908   }
 909   p = GNUNET_DNSPARSER_parse ((const char *) dns,
 910                               dns_len);
 911   if (NULL == p)
 912   {
 913     GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
 914                 _("Failed to parse DNS response\n"));
 915     return;
 916   }
 917
 918   /* We got a result from DNS */
 919   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 920               "Received DNS response for `%s' with %u answers\n",
 921               rh->ac_tail->label,
 922               (unsigned int) p->num_answers);
 923   if ( (p->num_answers > 0) &&
 924        (GNUNET_DNSPARSER_TYPE_CNAME == p->answers[0].type) &&
 925        (GNUNET_DNSPARSER_TYPE_CNAME != rh->record_type) )
 926   {
 927     int af;
 928
 929     GNUNET_log (GNUNET_ERROR_TYPE_INFO,
 930                 "Got CNAME `%s' from DNS for `%s'\n",
 931                 p->answers[0].data.hostname,
 932                 rh->name);
 933     if (NULL != rh->std_resolve)
 934     {
 935       GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
 936                   "Multiple CNAME results from DNS resolving `%s'! Not really allowed...\n",
 937                   rh->name);
 938       GNUNET_RESOLVER_request_cancel (rh->std_resolve);
 939     }
 940     GNUNET_free (rh->name);
 941     rh->name = GNUNET_strdup (p->answers[0].data.hostname);
 942     rh->name_resolution_pos = strlen (rh->name);
 943     switch (rh->record_type)
 944     {
 945     case GNUNET_DNSPARSER_TYPE_A:
 946       af = AF_INET;
 947       break;
 948     case GNUNET_DNSPARSER_TYPE_AAAA:
 949       af = AF_INET6;
 950       break;
 951     default:
 952       af = AF_UNSPEC;
 953       break;
 954     }
 955     if (NULL != rh->leho)
 956       add_dns_result (rh,
 957                       GNUNET_TIME_UNIT_HOURS.rel_value_us,
 958                       GNUNET_GNSRECORD_TYPE_LEHO,
 959                       strlen (rh->leho),
 960                       rh->leho);
 961     rh->std_resolve = GNUNET_RESOLVER_ip_get (rh->name,
 962                                               af,
 963                                               DNS_LOOKUP_TIMEOUT,
 964                                               &handle_dns_result,
 965                                               rh);
 966     GNUNET_DNSPARSER_free_packet (p);
 967     GNUNET_DNSSTUB_resolve_cancel (rh->dns_request);
 968     rh->dns_request = NULL;
 969     return;
 970   }
 971
 972   /* convert from (parsed) DNS to (binary) GNS format! */
 973   rd_count = p->num_answers + p->num_authority_records + p->num_additional_records;
 974   {
 975     struct GNUNET_GNSRECORD_Data rd[rd_count + 1]; /* +1 for LEHO */
 976     int skip;
 977     char buf[UINT16_MAX];
 978     size_t buf_off;
 979     size_t buf_start;
 980
 981     buf_off = 0;
 982     skip = 0;
 983     memset (rd,
 984             0,
 985             sizeof (rd));
 986     for (unsigned int i=0;i<rd_count;i++)
 987     {
 988       if (i < p->num_answers)
 989         rec = &p->answers[i];
 990       else if (i < p->num_answers + p->num_authority_records)
 991         rec = &p->authority_records[i - p->num_answers];
 992       else
 993         rec = &p->additional_records[i - p->num_answers - p->num_authority_records];
 994       /* As we copied the full DNS name to 'rh->ac_tail->label', this
 995          should be the correct check to see if this record is actually
 996          a record for our label... */
 997       if (0 != strcmp (rec->name,
 998                        rh->ac_tail->label))
 999       {
1000         GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1001                     "Dropping record `%s', does not match desired name `%s'\n",
1002                     rec->name,
1003                     rh->ac_tail->label);
1004         skip++;
1005         continue;
1006       }
1007       rd[i - skip].record_type = rec->type;
1008       rd[i - skip].expiration_time = rec->expiration_time.abs_value_us;
1009       switch (rec->type)
1010       {
1011       case GNUNET_DNSPARSER_TYPE_A:
1012         if (rec->data.raw.data_len != sizeof (struct in_addr))
1013         {
1014           GNUNET_break_op (0);
1015           skip++;
1016           continue;
1017         }
1018         rd[i - skip].data_size = rec->data.raw.data_len;
1019         rd[i - skip].data = rec->data.raw.data;
1020         break;
1021       case GNUNET_DNSPARSER_TYPE_AAAA:
1022         if (rec->data.raw.data_len != sizeof (struct in6_addr))
1023         {
1024           GNUNET_break_op (0);
1025           skip++;
1026           continue;
1027         }
1028         rd[i - skip].data_size = rec->data.raw.data_len;
1029         rd[i - skip].data = rec->data.raw.data;
1030         break;
1031       case GNUNET_DNSPARSER_TYPE_CNAME:
1032       case GNUNET_DNSPARSER_TYPE_PTR:
1033       case GNUNET_DNSPARSER_TYPE_NS:
1034         buf_start = buf_off;
1035         if (GNUNET_OK !=
1036             GNUNET_DNSPARSER_builder_add_name (buf,
1037                                                sizeof (buf),
1038                                                &buf_off,
1039                                                rec->data.hostname))
1040         {
1041           GNUNET_break (0);
1042           skip++;
1043           continue;
1044         }
1045         rd[i - skip].data_size = buf_off - buf_start;
1046         rd[i - skip].data = &buf[buf_start];
1047         break;
1048       case GNUNET_DNSPARSER_TYPE_SOA:
1049         buf_start = buf_off;
1050         if (GNUNET_OK !=
1051             GNUNET_DNSPARSER_builder_add_soa (buf,
1052                                               sizeof (buf),
1053                                               &buf_off,
1054                                               rec->data.soa))
1055         {
1056           GNUNET_break (0);
1057           skip++;
1058           continue;
1059         }
1060         rd[i - skip].data_size = buf_off - buf_start;
1061         rd[i - skip].data = &buf[buf_start];
1062         break;
1063       case GNUNET_DNSPARSER_TYPE_MX:
1064         buf_start = buf_off;
1065         if (GNUNET_OK !=
1066             GNUNET_DNSPARSER_builder_add_mx (buf,
1067                                              sizeof (buf),
1068                                              &buf_off,
1069                                              rec->data.mx))
1070         {
1071           GNUNET_break (0);
1072           skip++;
1073           continue;
1074         }
1075         rd[i - skip].data_size = buf_off - buf_start;
1076         rd[i - skip].data = &buf[buf_start];
1077         break;
1078       case GNUNET_DNSPARSER_TYPE_SRV:
1079         buf_start = buf_off;
1080         if (GNUNET_OK !=
1081             GNUNET_DNSPARSER_builder_add_srv (buf,
1082                                               sizeof (buf),
1083                                               &buf_off,
1084                                               rec->data.srv))
1085         {
1086           GNUNET_break (0);
1087           skip++;
1088           continue;
1089         }
1090         rd[i - skip].data_size = buf_off - buf_start;
1091         rd[i - skip].data = &buf[buf_start];
1092         break;
1093       default:
1094         GNUNET_log (GNUNET_ERROR_TYPE_INFO,
1095                     _("Skipping record of unsupported type %d\n"),
1096                     rec->type);
1097         skip++;
1098         continue;
1099       }
1100     } /* end of for all records in answer */
1101     if (NULL != rh->leho)
1102     {
1103       rd[rd_count - skip].record_type = GNUNET_GNSRECORD_TYPE_LEHO;
1104       rd[rd_count - skip].flags = GNUNET_GNSRECORD_RF_RELATIVE_EXPIRATION;
1105       rd[rd_count - skip].expiration_time = GNUNET_TIME_UNIT_HOURS.rel_value_us;
1106       rd[rd_count - skip].data = rh->leho;
1107       rd[rd_count - skip].data_size = strlen (rh->leho);
1108       skip--; /* skip one LESS */
1109       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1110                   "Adding LEHO %s\n",
1111                   rh->leho);
1112     }
1113     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1114                 "Returning DNS response for `%s' with %u answers\n",
1115                 rh->ac_tail->label,
1116                 (unsigned int) (rd_count - skip));
1117     rh->proc (rh->proc_cls,
1118               rd_count - skip,
1119               rd);
1120     GNUNET_DNSSTUB_resolve_cancel (rh->dns_request);
1121     rh->dns_request = NULL;
1122   }
1123   GNUNET_DNSPARSER_free_packet (p);
1124   if (NULL != rh->task_id)
1125     GNUNET_SCHEDULER_cancel (rh->task_id); /* should be timeout task */
1126   rh->task_id = GNUNET_SCHEDULER_add_now (&GNS_resolver_lookup_cancel_,
1127                                           rh);
1128 }
1129
1130
1131 /**
1132  * Perform recursive DNS resolution.  Asks the given DNS resolver to
1133  * resolve "rh->dns_name", possibly recursively proceeding following
1134  * NS delegations, CNAMES, etc., until 'rh->loop_limiter' bounds us or
1135  * we find the answer.
1136  *
1137  * @param rh resolution information
1138  */
1139 static void
1140 recursive_dns_resolution (struct GNS_ResolverHandle *rh)
1141 {
1142   struct AuthorityChain *ac;
1143   struct GNUNET_DNSPARSER_Query *query;
1144   struct GNUNET_DNSPARSER_Packet *p;
1145   char *dns_request;
1146   size_t dns_request_length;
1147   int ret;
1148
1149   ac = rh->ac_tail;
1150   GNUNET_assert (NULL != ac);
1151   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1152               "Starting DNS lookup for `%s'\n",
1153               ac->label);
1154   GNUNET_assert (GNUNET_NO == ac->gns_authority);
1155   query = GNUNET_new (struct GNUNET_DNSPARSER_Query);
1156   query->name = GNUNET_strdup (ac->label);
1157   query->type = rh->record_type;
1158   query->dns_traffic_class = GNUNET_TUN_DNS_CLASS_INTERNET;
1159   p = GNUNET_new (struct GNUNET_DNSPARSER_Packet);
1160   p->queries = query;
1161   p->num_queries = 1;
1162   p->id = (uint16_t) GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE,
1163                                                UINT16_MAX);
1164   p->flags.opcode = GNUNET_TUN_DNS_OPCODE_QUERY;
1165   p->flags.recursion_desired = 1;
1166   ret = GNUNET_DNSPARSER_pack (p,
1167                                1024,
1168                                &dns_request,
1169                                &dns_request_length);
1170   if (GNUNET_OK != ret)
1171   {
1172     GNUNET_break (0);
1173     rh->proc (rh->proc_cls,
1174               0,
1175               NULL);
1176     GNUNET_assert (NULL == rh->task_id);
1177     rh->task_id = GNUNET_SCHEDULER_add_now (&GNS_resolver_lookup_cancel_,
1178                                             rh);
1179   }
1180   else
1181   {
1182     rh->original_dns_id = p->id;
1183     GNUNET_assert (NULL != ac->authority_info.dns_authority.dns_handle);
1184     GNUNET_assert (NULL == rh->dns_request);
1185     rh->leho = GNUNET_strdup (ac->label);
1186     rh->dns_request = GNUNET_DNSSTUB_resolve (ac->authority_info.dns_authority.dns_handle,
1187                                               dns_request,
1188                                               dns_request_length,
1189                                               &dns_result_parser,
1190                                               rh);
1191     rh->task_id = GNUNET_SCHEDULER_add_delayed (DNS_LOOKUP_TIMEOUT,
1192                                                 &timeout_resolution,
1193                                                 rh);
1194   }
1195   if (GNUNET_SYSERR != ret)
1196     GNUNET_free (dns_request);
1197   GNUNET_DNSPARSER_free_packet (p);
1198 }
1199
1200
1201 /**
1202  * We encountered a CNAME record during our resolution.
1203  * Merge it into our chain.
1204  *
1205  * @param rh resolution we are performing
1206  * @param cname value of the cname record we got for the current
1207  *        authority chain tail
1208  */
1209 static void
1210 handle_gns_cname_result (struct GNS_ResolverHandle *rh,
1211                          const char *cname)
1212 {
1213   size_t nlen;
1214   char *res;
1215   struct AuthorityChain *ac;
1216   int af;
1217
1218   nlen = strlen (cname);
1219   if ( (nlen > 2) &&
1220        (0 == strcmp (".+",
1221                      &cname[nlen - 2])) )
1222   {
1223     /* CNAME resolution continues relative to current domain */
1224     if (0 == rh->name_resolution_pos)
1225     {
1226       res = GNUNET_strndup (cname, nlen - 2);
1227       rh->name_resolution_pos = nlen - 2;
1228     }
1229     else
1230     {
1231       GNUNET_asprintf (&res,
1232                        "%.*s.%.*s",
1233                        (int) rh->name_resolution_pos,
1234                        rh->name,
1235                        (int) (nlen - 2),
1236                        cname);
1237       rh->name_resolution_pos = strlen (res);
1238     }
1239     GNUNET_free (rh->name);
1240     rh->name = res;
1241     ac = GNUNET_new (struct AuthorityChain);
1242     ac->rh = rh;
1243     ac->gns_authority = GNUNET_YES;
1244     ac->authority_info.gns_authority = rh->ac_tail->authority_info.gns_authority;
1245     ac->label = resolver_lookup_get_next_label (rh);
1246     /* add AC to tail */
1247     GNUNET_CONTAINER_DLL_insert_tail (rh->ac_head,
1248                                       rh->ac_tail,
1249                                       ac);
1250     rh->task_id = GNUNET_SCHEDULER_add_now (&recursive_resolution,
1251                                             rh);
1252     return;
1253   }
1254   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
1255               "Got CNAME `%s' from GNS for `%s'\n",
1256               cname,
1257               rh->name);
1258   if (NULL != rh->std_resolve)
1259   {
1260     GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
1261                 "Multiple CNAME results from GNS resolving `%s'! Not really allowed...\n",
1262                 rh->name);
1263     GNUNET_RESOLVER_request_cancel (rh->std_resolve);
1264   }
1265   /* name is absolute, go to DNS */
1266   GNUNET_free (rh->name);
1267   rh->name = GNUNET_strdup (cname);
1268   rh->name_resolution_pos = strlen (rh->name);
1269   switch (rh->record_type)
1270   {
1271   case GNUNET_DNSPARSER_TYPE_A:
1272     af = AF_INET;
1273     break;
1274   case GNUNET_DNSPARSER_TYPE_AAAA:
1275     af = AF_INET6;
1276     break;
1277   default:
1278     af = AF_UNSPEC;
1279     break;
1280   }
1281   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1282               "Doing standard DNS lookup for `%s'\n",
1283               rh->name);
1284   rh->std_resolve = GNUNET_RESOLVER_ip_get (rh->name,
1285                                             af,
1286                                             DNS_LOOKUP_TIMEOUT,
1287                                             &handle_dns_result,
1288                                             rh);
1289 }
1290
1291
1292 /**
1293  * Process a records that were decrypted from a block.
1294  *
1295  * @param cls closure with the 'struct GNS_ResolverHandle'
1296  * @param rd_count number of entries in @a rd array
1297  * @param rd array of records with data to store
1298  */
1299 static void
1300 handle_gns_resolution_result (void *cls,
1301                               unsigned int rd_count,
1302                               const struct GNUNET_GNSRECORD_Data *rd);
1303
1304
1305 /**
1306  * Callback invoked from the VPN service once a redirection is
1307  * available.  Provides the IP address that can now be used to
1308  * reach the requested destination.  Replaces the "VPN" record
1309  * with the respective A/AAAA record and continues processing.
1310  *
1311  * @param cls closure
1312  * @param af address family, AF_INET or AF_INET6; AF_UNSPEC on error;
1313  *                will match 'result_af' from the request
1314  * @param address IP address (struct in_addr or struct in_addr6, depending on 'af')
1315  *                that the VPN allocated for the redirection;
1316  *                traffic to this IP will now be redirected to the
1317  *                specified target peer; NULL on error
1318  */
1319 static void
1320 vpn_allocation_cb (void *cls,
1321                    int af,
1322                    const void *address)
1323 {
1324   struct VpnContext *vpn_ctx = cls;
1325   struct GNS_ResolverHandle *rh = vpn_ctx->rh;
1326   struct GNUNET_GNSRECORD_Data rd[vpn_ctx->rd_count];
1327   unsigned int i;
1328
1329   vpn_ctx->vpn_request = NULL;
1330   rh->vpn_ctx = NULL;
1331   GNUNET_assert (GNUNET_OK ==
1332                  GNUNET_GNSRECORD_records_deserialize ((size_t) vpn_ctx->rd_data_size,
1333                                                        vpn_ctx->rd_data,
1334                                                        vpn_ctx->rd_count,
1335                                                        rd));
1336   for (i=0;i<vpn_ctx->rd_count;i++)
1337   {
1338     if (GNUNET_GNSRECORD_TYPE_VPN == rd[i].record_type)
1339     {
1340       switch (af)
1341       {
1342       case AF_INET:
1343         rd[i].record_type = GNUNET_DNSPARSER_TYPE_A;
1344         rd[i].data_size = sizeof (struct in_addr);
1345         rd[i].expiration_time = GNUNET_TIME_relative_to_absolute (VPN_TIMEOUT).abs_value_us;
1346         rd[i].flags = 0;
1347         rd[i].data = address;
1348         break;
1349       case AF_INET6:
1350         rd[i].record_type = GNUNET_DNSPARSER_TYPE_AAAA;
1351         rd[i].expiration_time = GNUNET_TIME_relative_to_absolute (VPN_TIMEOUT).abs_value_us;
1352         rd[i].flags = 0;
1353         rd[i].data = address;
1354         rd[i].data_size = sizeof (struct in6_addr);
1355         break;
1356       default:
1357         GNUNET_assert (0);
1358       }
1359       break;
1360     }
1361   }
1362   GNUNET_assert (i < vpn_ctx->rd_count);
1363   if (0 == vpn_ctx->rd_count)
1364     GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
1365                 _("VPN returned empty result for `%s'\n"),
1366                 rh->name);
1367   handle_gns_resolution_result (rh,
1368                                 vpn_ctx->rd_count,
1369                                 rd);
1370   GNUNET_free (vpn_ctx->rd_data);
1371   GNUNET_free (vpn_ctx);
1372 }
1373
1374
1375 /**
1376  * We have resolved one or more of the nameservers for a
1377  * GNS2DNS lookup.  Once we have some of them, begin using
1378  * the DNSSTUB resolver.
1379  *
1380  * @param ac context for GNS2DNS resolution
1381  */
1382 static void
1383 continue_with_gns2dns (struct AuthorityChain *ac)
1384 {
1385   struct GNS_ResolverHandle *rh = ac->rh;
1386
1387   if ( (NULL != ac->authority_info.dns_authority.gp_head) &&
1388        (GNUNET_NO == ac->authority_info.dns_authority.found) )
1389     return; /* more pending and none found yet */
1390   if (GNUNET_NO == ac->authority_info.dns_authority.found)
1391   {
1392     GNUNET_log (GNUNET_ERROR_TYPE_INFO,
1393                 "Failed to resolve DNS server for `%s' in GNS2DNS resolution\n",
1394                 ac->authority_info.dns_authority.name);
1395     fail_resolution (rh);
1396     return;
1397   }
1398   if (GNUNET_NO != ac->authority_info.dns_authority.launched)
1399     return; /* already running, do not launch again! */
1400   /* recurse */
1401   ac->authority_info.dns_authority.launched = GNUNET_YES;
1402   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1403               "Will continue resolution using DNS to resolve `%s'\n",
1404               ac->label);
1405   GNUNET_assert (NULL == rh->task_id);
1406   rh->task_id = GNUNET_SCHEDULER_add_now (&recursive_resolution,
1407                                           rh);
1408
1409 }
1410
1411
1412 /**
1413  * We've resolved the IP address for the DNS resolver to use
1414  * after encountering a GNS2DNS record.
1415  *
1416  * @param cls the `struct Gns2DnsPending` used for this request
1417  * @param rd_count number of records in @a rd
1418  * @param rd addresses for the DNS resolver  (presumably)
1419  */
1420 static void
1421 handle_gns2dns_result (void *cls,
1422                        unsigned int rd_count,
1423                        const struct GNUNET_GNSRECORD_Data *rd)
1424 {
1425   struct Gns2DnsPending *gp = cls;
1426   struct AuthorityChain *ac = gp->ac;
1427
1428   GNUNET_CONTAINER_DLL_remove (ac->authority_info.dns_authority.gp_head,
1429                                ac->authority_info.dns_authority.gp_tail,
1430                                gp);
1431   /* enable cleanup of 'rh' handle that automatically comes after we return,
1432      and which expects 'rh' to be in the #rlh_head DLL. */
1433   if (NULL != gp->rh)
1434   {
1435     GNUNET_CONTAINER_DLL_insert (rlh_head,
1436                                  rlh_tail,
1437                                  gp->rh);
1438     gp->rh = NULL;
1439   }
1440   GNUNET_free (gp);
1441   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1442               "Received %u results for IP address of DNS server for GNS2DNS transition\n",
1443               rd_count);
1444   /* find suitable A/AAAA record */
1445   for (unsigned int j=0;j<rd_count;j++)
1446   {
1447     switch (rd[j].record_type)
1448     {
1449     case GNUNET_DNSPARSER_TYPE_A:
1450       {
1451         struct sockaddr_in v4;
1452
1453         if (sizeof (struct in_addr) != rd[j].data_size)
1454         {
1455           GNUNET_break_op (0);
1456           continue;
1457         }
1458         memset (&v4,
1459                 0,
1460                 sizeof (v4));
1461         v4.sin_family = AF_INET;
1462         v4.sin_port = htons (53);
1463 #if HAVE_SOCKADDR_IN_SIN_LEN
1464         v4.sin_len = (u_char) sizeof (v4);
1465 #endif
1466         GNUNET_memcpy (&v4.sin_addr,
1467                        rd[j].data,
1468                        sizeof (struct in_addr));
1469         if (GNUNET_OK ==
1470             GNUNET_DNSSTUB_add_dns_sa (ac->authority_info.dns_authority.dns_handle,
1471                                        (const struct sockaddr *) &v4))
1472           ac->authority_info.dns_authority.found = GNUNET_YES;
1473         break;
1474       }
1475     case GNUNET_DNSPARSER_TYPE_AAAA:
1476       {
1477         struct sockaddr_in6 v6;
1478
1479         if (sizeof (struct in6_addr) != rd[j].data_size)
1480         {
1481           GNUNET_break_op (0);
1482           continue;
1483         }
1484         /* FIXME: might want to check if we support IPv6 here,
1485            and otherwise skip this one and hope we find another */
1486         memset (&v6,
1487                 0,
1488                 sizeof (v6));
1489         v6.sin6_family = AF_INET6;
1490         v6.sin6_port = htons (53);
1491 #if HAVE_SOCKADDR_IN_SIN_LEN
1492         v6.sin6_len = (u_char) sizeof (v6);
1493 #endif
1494         GNUNET_memcpy (&v6.sin6_addr,
1495                        rd[j].data,
1496                        sizeof (struct in6_addr));
1497         if (GNUNET_OK ==
1498             GNUNET_DNSSTUB_add_dns_sa (ac->authority_info.dns_authority.dns_handle,
1499                                        (const struct sockaddr *) &v6))
1500           ac->authority_info.dns_authority.found = GNUNET_YES;
1501         break;
1502       }
1503     default:
1504       break;
1505     }
1506   }
1507   continue_with_gns2dns (ac);
1508 }
1509
1510
1511 /**
1512  * Function called by the resolver for each address obtained from DNS.
1513  *
1514  * @param cls closure, a `struct Gns2DnsPending *`
1515  * @param addr one of the addresses of the host, NULL for the last address
1516  * @param addrlen length of @a addr
1517  */
1518 static void
1519 handle_gns2dns_ip (void *cls,
1520                    const struct sockaddr *addr,
1521                    socklen_t addrlen)
1522 {
1523   struct Gns2DnsPending *gp = cls;
1524   struct AuthorityChain *ac = gp->ac;
1525   struct sockaddr_storage ss;
1526   struct sockaddr_in *v4;
1527   struct sockaddr_in6 *v6;
1528
1529   if (NULL == addr)
1530   {
1531     /* DNS resolution finished */
1532     if (0 == gp->num_results)
1533       GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
1534                   "Failed to use DNS to resolve name of DNS resolver\n");
1535     GNUNET_CONTAINER_DLL_remove (ac->authority_info.dns_authority.gp_head,
1536                                  ac->authority_info.dns_authority.gp_tail,
1537                                  gp);
1538     GNUNET_free (gp);
1539     continue_with_gns2dns (ac);
1540     return;
1541   }
1542   GNUNET_memcpy (&ss,
1543                  addr,
1544                  addrlen);
1545   switch (ss.ss_family)
1546   {
1547   case AF_INET:
1548     v4 = (struct sockaddr_in *) &ss;
1549     v4->sin_port = htons (53);
1550     gp->num_results++;
1551     break;
1552   case AF_INET6:
1553     v6 = (struct sockaddr_in6 *) &ss;
1554     v6->sin6_port = htons (53);
1555     gp->num_results++;
1556     break;
1557   default:
1558     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
1559                 "Unsupported AF %d\n",
1560                 ss.ss_family);
1561     return;
1562   }
1563   if (GNUNET_OK ==
1564       GNUNET_DNSSTUB_add_dns_sa (ac->authority_info.dns_authority.dns_handle,
1565                                  (struct sockaddr *) &ss))
1566     ac->authority_info.dns_authority.found = GNUNET_YES;
1567 }
1568
1569
1570 /**
1571  * We found a CNAME record, perform recursive resolution on it.
1572  *
1573  * @param rh resolution handle
1574  * @param rd record with CNAME to resolve recursively
1575  */
1576 static void
1577 recursive_cname_resolution (struct GNS_ResolverHandle *rh,
1578                             const struct GNUNET_GNSRECORD_Data *rd)
1579 {
1580   char *cname;
1581   size_t off;
1582
1583   off = 0;
1584   cname = GNUNET_DNSPARSER_parse_name (rd->data,
1585                                        rd->data_size,
1586                                        &off);
1587   if ( (NULL == cname) ||
1588        (off != rd->data_size) )
1589   {
1590     GNUNET_break_op (0); /* record not well-formed */
1591     GNUNET_free_non_null (cname);
1592     fail_resolution (rh);
1593     return;
1594   }
1595   handle_gns_cname_result (rh,
1596                            cname);
1597   GNUNET_free (cname);
1598 }
1599
1600
1601 /**
1602  * We found a PKEY record, perform recursive resolution on it.
1603  *
1604  * @param rh resolution handle
1605  * @param rd record with PKEY to resolve recursively
1606  */
1607 static void
1608 recursive_pkey_resolution (struct GNS_ResolverHandle *rh,
1609                            const struct GNUNET_GNSRECORD_Data *rd)
1610 {
1611   struct AuthorityChain *ac;
1612
1613   /* delegation to another zone */
1614   if (sizeof (struct GNUNET_CRYPTO_EcdsaPublicKey) !=
1615       rd->data_size)
1616   {
1617     GNUNET_break_op (0);
1618     fail_resolution (rh);
1619     return;
1620   }
1621   /* expand authority chain */
1622   ac = GNUNET_new (struct AuthorityChain);
1623   ac->rh = rh;
1624   ac->gns_authority = GNUNET_YES;
1625   GNUNET_memcpy (&ac->authority_info.gns_authority,
1626                  rd->data,
1627                  sizeof (struct GNUNET_CRYPTO_EcdsaPublicKey));
1628   ac->label = resolver_lookup_get_next_label (rh);
1629   /* add AC to tail */
1630   GNUNET_CONTAINER_DLL_insert_tail (rh->ac_head,
1631                                     rh->ac_tail,
1632                                     ac);
1633   /* recurse */
1634   rh->task_id = GNUNET_SCHEDULER_add_now (&recursive_resolution,
1635                                           rh);
1636 }
1637
1638
1639 /**
1640  * We found one or more GNS2DNS records, perform recursive resolution on it.
1641  * (to be precise, one or more records in @a rd is GNS2DNS, there may be others,
1642  * so this function still needs to check which ones are GNS2DNS).
1643  *
1644  * @param rh resolution handle
1645  * @param rd_count length of the @a rd array
1646  * @param rd record with PKEY to resolve recursively
1647  * @return #GNUNET_OK if this worked, #GNUNET_SYSERR if no GNS2DNS records were in @a rd
1648  */
1649 static int
1650 recursive_gns2dns_resolution (struct GNS_ResolverHandle *rh,
1651                               unsigned int rd_count,
1652                               const struct GNUNET_GNSRECORD_Data *rd)
1653 {
1654   struct AuthorityChain *ac;
1655   const char *tld;
1656   char *ns;
1657
1658   ns = NULL;
1659   /* expand authority chain */
1660   ac = GNUNET_new (struct AuthorityChain);
1661   ac->rh = rh;
1662   ac->authority_info.dns_authority.dns_handle = GNUNET_DNSSTUB_start (4);
1663
1664   for (unsigned int i=0;i<rd_count;i++)
1665   {
1666     char *ip;
1667     char *n;
1668     size_t off;
1669     struct Gns2DnsPending *gp;
1670     struct GNUNET_CRYPTO_EcdsaPublicKey zone;
1671     struct sockaddr_in v4;
1672     struct sockaddr_in6 v6;
1673
1674     if (GNUNET_GNSRECORD_TYPE_GNS2DNS != rd[i].record_type)
1675       continue;
1676     off = 0;
1677     n = GNUNET_DNSPARSER_parse_name (rd[i].data,
1678                                      rd[i].data_size,
1679                                      &off);
1680     ip = GNUNET_DNSPARSER_parse_name (rd[i].data,
1681                                       rd[i].data_size,
1682                                       &off);
1683     if ( (NULL == n) ||
1684          (NULL == ip) ||
1685          (off != rd[i].data_size) )
1686     {
1687       GNUNET_break_op (0);
1688       GNUNET_free_non_null (n);
1689       GNUNET_free_non_null (ip);
1690       continue;
1691     }
1692     /* resolve 'ip' to determine the IP(s) of the DNS
1693        resolver to use for lookup of 'ns' */
1694     if (NULL != ns)
1695     {
1696       if (0 != strcasecmp (ns,
1697                            n))
1698       {
1699         /* NS values must all be the same for all GNS2DNS records,
1700            anything else leads to insanity */
1701         GNUNET_break_op (0);
1702         GNUNET_free (n);
1703         GNUNET_free (ip);
1704         continue;
1705       }
1706       GNUNET_free (n);
1707     }
1708     else
1709     {
1710       ns = n;
1711     }
1712
1713     /* check if 'ip' is already an IPv4/IPv6 address */
1714     if ( (1 == inet_pton (AF_INET,
1715                           ip,
1716                           &v4)) ||
1717          (1 == inet_pton (AF_INET6,
1718                           ip,
1719                           &v6)) )
1720     {
1721       GNUNET_break (GNUNET_OK ==
1722                     GNUNET_DNSSTUB_add_dns_ip (ac->authority_info.dns_authority.dns_handle,
1723                                                ip));
1724       ac->authority_info.dns_authority.found = GNUNET_YES;
1725       GNUNET_free (ip);
1726       continue;
1727     }
1728     tld = GNS_get_tld (ip);
1729     if (0 != strcmp (tld,
1730                      "+"))
1731     {
1732       /* 'ip' is a DNS name */
1733       gp = GNUNET_new (struct Gns2DnsPending);
1734       gp->ac = ac;
1735       GNUNET_CONTAINER_DLL_insert (ac->authority_info.dns_authority.gp_head,
1736                                    ac->authority_info.dns_authority.gp_tail,
1737                                    gp);
1738       gp->dns_rh = GNUNET_RESOLVER_ip_get (ip,
1739                                            AF_UNSPEC,
1740                                            GNUNET_TIME_UNIT_FOREVER_REL,
1741                                            &handle_gns2dns_ip,
1742                                            gp);
1743       GNUNET_free (ip);
1744       continue;
1745     }
1746     /* 'ip' should be a GNS name */
1747     gp = GNUNET_new (struct Gns2DnsPending);
1748     gp->ac = ac;
1749     GNUNET_CONTAINER_DLL_insert (ac->authority_info.dns_authority.gp_head,
1750                                  ac->authority_info.dns_authority.gp_tail,
1751                                  gp);
1752     gp->rh = GNUNET_new (struct GNS_ResolverHandle);
1753     ip = translate_dot_plus (rh,
1754                              ip);
1755     tld = GNS_get_tld (ip);
1756     if (GNUNET_OK !=
1757         GNUNET_GNSRECORD_zkey_to_pkey (tld,
1758                                        &zone))
1759     {
1760       GNUNET_break_op (0);
1761       GNUNET_free (ip);
1762       continue;
1763     }
1764     gp->rh->authority_zone = zone;
1765     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1766                 "Resolving `%s' to determine IP address of DNS server for GNS2DNS transition for `%s'\n",
1767                 ip,
1768                 ns);
1769     gp->rh->name = ip;
1770     gp->rh->name_resolution_pos = strlen (ip) - strlen (tld) - 1;
1771     gp->rh->proc = &handle_gns2dns_result;
1772     gp->rh->proc_cls = gp;
1773     gp->rh->record_type = GNUNET_GNSRECORD_TYPE_ANY;
1774     gp->rh->options = GNUNET_GNS_LO_DEFAULT;
1775     gp->rh->loop_limiter = rh->loop_limiter + 1;
1776     gp->rh->task_id
1777       = GNUNET_SCHEDULER_add_now (&start_resolver_lookup,
1778                                   gp->rh);
1779   } /* end 'for all records' */
1780
1781   if (NULL == ns)
1782   {
1783     /* not a single GNS2DNS record found */
1784     GNUNET_free (ac);
1785     return GNUNET_SYSERR;
1786   }
1787   GNUNET_assert (strlen (ns) <= GNUNET_DNSPARSER_MAX_NAME_LENGTH);
1788   strcpy (ac->authority_info.dns_authority.name,
1789           ns);
1790   /* for DNS recursion, the label is the full DNS name,
1791      created from the remainder of the GNS name and the
1792      name in the NS record */
1793   GNUNET_asprintf (&ac->label,
1794                    "%.*s%s%s",
1795                    (int) rh->name_resolution_pos,
1796                    rh->name,
1797                    (0 != rh->name_resolution_pos) ? "." : "",
1798                    ns);
1799   GNUNET_free (ns);
1800   GNUNET_CONTAINER_DLL_insert_tail (rh->ac_head,
1801                                     rh->ac_tail,
1802                                     ac);
1803   if (strlen (ac->label) > GNUNET_DNSPARSER_MAX_NAME_LENGTH)
1804   {
1805     GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
1806                 _("GNS lookup resulted in DNS name that is too long (`%s')\n"),
1807                 ac->label);
1808     return GNUNET_SYSERR;
1809   }
1810   continue_with_gns2dns (ac);
1811   return GNUNET_OK;
1812 }
1813
1814
1815 /**
1816  * Process a records that were decrypted from a block.
1817  *
1818  * @param cls closure with the `struct GNS_ResolverHandle`
1819  * @param rd_count number of entries in @a rd array
1820  * @param rd array of records with data to store
1821  */
1822 static void
1823 handle_gns_resolution_result (void *cls,
1824                               unsigned int rd_count,
1825                               const struct GNUNET_GNSRECORD_Data *rd)
1826 {
1827   struct GNS_ResolverHandle *rh = cls;
1828   char *cname;
1829   struct VpnContext *vpn_ctx;
1830   const struct GNUNET_TUN_GnsVpnRecord *vpn;
1831   const char *vname;
1832   struct GNUNET_HashCode vhash;
1833   int af;
1834   char scratch[UINT16_MAX];
1835   size_t scratch_off;
1836   size_t scratch_start;
1837   size_t off;
1838   struct GNUNET_GNSRECORD_Data rd_new[rd_count];
1839   unsigned int rd_off;
1840
1841   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
1842               "Resolution succeeded for `%s' in zone %s, got %u records\n",
1843               rh->ac_tail->label,
1844               GNUNET_GNSRECORD_z2s (&rh->ac_tail->authority_info.gns_authority),
1845               rd_count);
1846   if (0 == rd_count)
1847   {
1848     GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
1849                 _("GNS lookup failed (zero records found for `%s')\n"),
1850                 rh->name);
1851     fail_resolution (rh);
1852     return;
1853   }
1854
1855   if (0 == rh->name_resolution_pos)
1856   {
1857     /* top-level match, are we done yet? */
1858     if ( (rd_count > 0) &&
1859          (GNUNET_DNSPARSER_TYPE_CNAME == rd[0].record_type) &&
1860          (GNUNET_DNSPARSER_TYPE_CNAME != rh->record_type) )
1861     {
1862       off = 0;
1863       cname = GNUNET_DNSPARSER_parse_name (rd[0].data,
1864                                            rd[0].data_size,
1865                                            &off);
1866       if ( (NULL == cname) ||
1867            (off != rd[0].data_size) )
1868       {
1869         GNUNET_break_op (0);
1870         GNUNET_free_non_null (cname);
1871         fail_resolution (rh);
1872         return;
1873       }
1874       handle_gns_cname_result (rh,
1875                                cname);
1876       GNUNET_free (cname);
1877       return;
1878     }
1879     /* If A/AAAA was requested, but we got a VPN
1880        record, we convert it to A/AAAA using GNUnet VPN */
1881     if ( (GNUNET_DNSPARSER_TYPE_A == rh->record_type) ||
1882          (GNUNET_DNSPARSER_TYPE_AAAA == rh->record_type) )
1883     {
1884       for (unsigned int i=0;i<rd_count;i++)
1885       {
1886         switch (rd[i].record_type)
1887         {
1888         case GNUNET_GNSRECORD_TYPE_VPN:
1889           {
1890             af = (GNUNET_DNSPARSER_TYPE_A == rh->record_type) ? AF_INET : AF_INET6;
1891             if (sizeof (struct GNUNET_TUN_GnsVpnRecord) >
1892                 rd[i].data_size)
1893             {
1894               GNUNET_break_op (0);
1895               fail_resolution (rh);
1896               return;
1897             }
1898             vpn = (const struct GNUNET_TUN_GnsVpnRecord *) rd[i].data;
1899             vname = (const char *) &vpn[1];
1900             if ('\0' != vname[rd[i].data_size - 1 - sizeof (struct GNUNET_TUN_GnsVpnRecord)])
1901             {
1902               GNUNET_break_op (0);
1903               fail_resolution (rh);
1904               return;
1905             }
1906             GNUNET_TUN_service_name_to_hash (vname,
1907                                              &vhash);
1908             GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1909                         "Attempting VPN allocation for %s-%s (AF: %d, proto %d)\n",
1910                         GNUNET_i2s (&vpn->peer),
1911                         vname,
1912                         (int) af,
1913                         (int) ntohs (vpn->proto));
1914             vpn_ctx = GNUNET_new (struct VpnContext);
1915             rh->vpn_ctx = vpn_ctx;
1916             vpn_ctx->rh = rh;
1917             vpn_ctx->rd_data_size = GNUNET_GNSRECORD_records_get_size (rd_count,
1918                                                                        rd);
1919             if (vpn_ctx->rd_data_size < 0)
1920             {
1921               GNUNET_break_op (0);
1922               GNUNET_free (vpn_ctx);
1923               fail_resolution (rh);
1924               return;
1925             }
1926             vpn_ctx->rd_data = GNUNET_malloc ((size_t) vpn_ctx->rd_data_size);
1927             vpn_ctx->rd_count = rd_count;
1928             GNUNET_assert (vpn_ctx->rd_data_size ==
1929                            GNUNET_GNSRECORD_records_serialize (rd_count,
1930                                                                rd,
1931                                                                (size_t) vpn_ctx->rd_data_size,
1932                                                                vpn_ctx->rd_data));
1933             vpn_ctx->vpn_request = GNUNET_VPN_redirect_to_peer (vpn_handle,
1934                                                                 af,
1935                                                                 ntohs (vpn->proto),
1936                                                                 &vpn->peer,
1937                                                                 &vhash,
1938                                                                 GNUNET_TIME_relative_to_absolute (VPN_TIMEOUT),
1939                                                                 &vpn_allocation_cb,
1940                                                                 vpn_ctx);
1941             return;
1942           }
1943         case GNUNET_GNSRECORD_TYPE_GNS2DNS:
1944           {
1945             /* delegation to DNS */
1946             GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1947                         "Found GNS2DNS record, delegating to DNS!\n");
1948             if (GNUNET_OK ==
1949                 recursive_gns2dns_resolution (rh,
1950                                               rd_count,
1951                                               rd))
1952               return;
1953             else
1954               goto fail;
1955           }
1956         default:
1957           break;
1958         } /* end: switch */
1959       } /* end: for rd */
1960     } /* end: name_resolution_pos */
1961     /* convert relative names in record values to absolute names,
1962        using 'scratch' array for memory allocations */
1963     scratch_off = 0;
1964     rd_off = 0;
1965     for (unsigned int i=0;i<rd_count;i++)
1966     {
1967       GNUNET_assert (rd_off <= i);
1968       if ( (0 != rh->protocol) &&
1969            (0 != rh->service) &&
1970            (GNUNET_GNSRECORD_TYPE_BOX != rd[i].record_type) )
1971         continue; /* we _only_ care about boxed records */
1972
1973       GNUNET_assert (rd_off < rd_count);
1974       rd_new[rd_off] = rd[i];
1975       /* Check if the embedded name(s) end in "+", and if so,
1976          replace the "+" with the zone at "ac_tail", changing the name
1977          to a ".ZONEKEY".  The name is allocated on the 'scratch' array,
1978          so we can free it afterwards. */
1979       switch (rd[i].record_type)
1980       {
1981       case GNUNET_DNSPARSER_TYPE_CNAME:
1982         {
1983           char *cname;
1984
1985           off = 0;
1986           cname = GNUNET_DNSPARSER_parse_name (rd[i].data,
1987                                                rd[i].data_size,
1988                                                &off);
1989           if ( (NULL == cname) ||
1990                (off != rd[i].data_size) )
1991           {
1992             GNUNET_break_op (0); /* record not well-formed */
1993           }
1994           else
1995           {
1996             cname = translate_dot_plus (rh, cname);
1997             GNUNET_break (NULL != cname);
1998             scratch_start = scratch_off;
1999             if (GNUNET_OK !=
2000                 GNUNET_DNSPARSER_builder_add_name (scratch,
2001                                                    sizeof (scratch),
2002                                                    &scratch_off,
2003                                                    cname))
2004             {
2005               GNUNET_break (0);
2006             }
2007             else
2008             {
2009               GNUNET_assert (rd_off < rd_count);
2010               rd_new[rd_off].data = &scratch[scratch_start];
2011               rd_new[rd_off].data_size = scratch_off - scratch_start;
2012               rd_off++;
2013             }
2014           }
2015           GNUNET_free_non_null (cname);
2016         }
2017         break;
2018       case GNUNET_DNSPARSER_TYPE_SOA:
2019         {
2020           struct GNUNET_DNSPARSER_SoaRecord *soa;
2021
2022           off = 0;
2023           soa = GNUNET_DNSPARSER_parse_soa (rd[i].data,
2024                                             rd[i].data_size,
2025                                             &off);
2026           if ( (NULL == soa) ||
2027                (off != rd[i].data_size) )
2028           {
2029             GNUNET_break_op (0); /* record not well-formed */
2030           }
2031           else
2032           {
2033             soa->mname = translate_dot_plus (rh, soa->mname);
2034             soa->rname = translate_dot_plus (rh, soa->rname);
2035             scratch_start = scratch_off;
2036             if (GNUNET_OK !=
2037                 GNUNET_DNSPARSER_builder_add_soa (scratch,
2038                                                   sizeof (scratch),
2039                                                   &scratch_off,
2040                                                   soa))
2041             {
2042               GNUNET_break (0);
2043             }
2044             else
2045             {
2046               GNUNET_assert (rd_off < rd_count);
2047               rd_new[rd_off].data = &scratch[scratch_start];
2048               rd_new[rd_off].data_size = scratch_off - scratch_start;
2049               rd_off++;
2050             }
2051           }
2052           if (NULL != soa)
2053             GNUNET_DNSPARSER_free_soa (soa);
2054         }
2055         break;
2056       case GNUNET_DNSPARSER_TYPE_MX:
2057         {
2058           struct GNUNET_DNSPARSER_MxRecord *mx;
2059
2060           off = 0;
2061           mx = GNUNET_DNSPARSER_parse_mx (rd[i].data,
2062                                           rd[i].data_size,
2063                                           &off);
2064           if ( (NULL == mx) ||
2065                (off != rd[i].data_size) )
2066           {
2067             GNUNET_break_op (0); /* record not well-formed */
2068           }
2069           else
2070           {
2071             mx->mxhost = translate_dot_plus (rh, mx->mxhost);
2072             scratch_start = scratch_off;
2073             if (GNUNET_OK !=
2074                 GNUNET_DNSPARSER_builder_add_mx (scratch,
2075                                                  sizeof (scratch),
2076                                                  &scratch_off,
2077                                                  mx))
2078             {
2079               GNUNET_break (0);
2080             }
2081             else
2082             {
2083               GNUNET_assert (rd_off < rd_count);
2084               rd_new[rd_off].data = &scratch[scratch_start];
2085               rd_new[rd_off].data_size = scratch_off - scratch_start;
2086               rd_off++;
2087             }
2088           }
2089           if (NULL != mx)
2090             GNUNET_DNSPARSER_free_mx (mx);
2091         }
2092         break;
2093       case GNUNET_DNSPARSER_TYPE_SRV:
2094         {
2095           struct GNUNET_DNSPARSER_SrvRecord *srv;
2096
2097           off = 0;
2098           srv = GNUNET_DNSPARSER_parse_srv (rd[i].data,
2099                                             rd[i].data_size,
2100                                             &off);
2101           if ( (NULL == srv) ||
2102                (off != rd[i].data_size) )
2103           {
2104             GNUNET_break_op (0); /* record not well-formed */
2105           }
2106           else
2107           {
2108             srv->target = translate_dot_plus (rh, srv->target);
2109             scratch_start = scratch_off;
2110             if (GNUNET_OK !=
2111                 GNUNET_DNSPARSER_builder_add_srv (scratch,
2112                                                   sizeof (scratch),
2113                                                   &scratch_off,
2114                                                   srv))
2115             {
2116               GNUNET_break (0);
2117             }
2118             else
2119             {
2120               GNUNET_assert (rd_off < rd_count);
2121               rd_new[rd_off].data = &scratch[scratch_start];
2122               rd_new[rd_off].data_size = scratch_off - scratch_start;
2123               rd_off++;
2124             }
2125           }
2126           if (NULL != srv)
2127             GNUNET_DNSPARSER_free_srv (srv);
2128         }
2129         break;
2130
2131       case GNUNET_GNSRECORD_TYPE_NICK:
2132         {
2133           const char *nick;
2134
2135           nick = rd[i].data;
2136           if ((rd[i].data_size > 0) &&
2137               (nick[rd[i].data_size -1] != '\0'))
2138           {
2139             GNUNET_break_op (0);
2140             break;
2141           }
2142           break;
2143         }
2144       case GNUNET_GNSRECORD_TYPE_PKEY:
2145         {
2146           struct GNUNET_CRYPTO_EcdsaPublicKey pub;
2147
2148           if (rd[i].data_size != sizeof (struct GNUNET_CRYPTO_EcdsaPublicKey))
2149           {
2150             GNUNET_break_op (0);
2151             break;
2152           }
2153           GNUNET_memcpy (&pub,
2154                          rd[i].data,
2155                          rd[i].data_size);
2156           rd_off++;
2157           if (GNUNET_GNSRECORD_TYPE_PKEY != rh->record_type)
2158           {
2159             /* try to resolve "@" */
2160             struct AuthorityChain *ac;
2161
2162             ac = GNUNET_new (struct AuthorityChain);
2163             ac->rh = rh;
2164             ac->gns_authority = GNUNET_YES;
2165             ac->authority_info.gns_authority = pub;
2166             ac->label = GNUNET_strdup (GNUNET_GNS_EMPTY_LABEL_AT);
2167             GNUNET_CONTAINER_DLL_insert_tail (rh->ac_head,
2168                                               rh->ac_tail,
2169                                               ac);
2170             rh->task_id = GNUNET_SCHEDULER_add_now (&recursive_resolution,
2171                                                     rh);
2172             return;
2173           }
2174         }
2175         break;
2176       case GNUNET_GNSRECORD_TYPE_GNS2DNS:
2177         {
2178           /* delegation to DNS */
2179           if (GNUNET_GNSRECORD_TYPE_GNS2DNS == rh->record_type)
2180           {
2181             rd_off++;
2182             break; /* do not follow to DNS, we wanted the GNS2DNS record! */
2183           }
2184           GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
2185                       "Found GNS2DNS record, delegating to DNS!\n");
2186           if (GNUNET_OK ==
2187               recursive_gns2dns_resolution (rh,
2188                                             rd_count,
2189                                             rd))
2190             return;
2191           else
2192             goto fail;
2193         }
2194       case GNUNET_GNSRECORD_TYPE_BOX:
2195         {
2196           /* unbox SRV/TLSA records if a specific one was requested */
2197           if ( (0 != rh->protocol) &&
2198                (0 != rh->service) &&
2199                (rd[i].data_size >= sizeof (struct GNUNET_GNSRECORD_BoxRecord)) )
2200           {
2201             const struct GNUNET_GNSRECORD_BoxRecord *box;
2202
2203             box = rd[i].data;
2204             if ( (ntohs (box->protocol) == rh->protocol) &&
2205                  (ntohs (box->service) == rh->service) )
2206             {
2207               /* Box matches, unbox! */
2208               GNUNET_assert (rd_off < rd_count);
2209               rd_new[rd_off].record_type = ntohl (box->record_type);
2210               rd_new[rd_off].data_size -= sizeof (struct GNUNET_GNSRECORD_BoxRecord);
2211               rd_new[rd_off].data = &box[1];
2212               rd_off++;
2213             }
2214           }
2215           else
2216           {
2217             /* no specific protocol/service specified, preserve all BOX
2218                records (for modern, GNS-enabled applications) */
2219             rd_off++;
2220           }
2221           break;
2222         }
2223       default:
2224         rd_off++;
2225         break;
2226       } /* end: switch */
2227     } /* end: for rd_count */
2228
2229     /* yes, we are done, return result */
2230     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
2231                 "Returning GNS response for `%s' with %u answers\n",
2232                 rh->ac_tail->label,
2233                 rd_off);
2234     rh->proc (rh->proc_cls,
2235               rd_off,
2236               rd_new);
2237     rh->task_id = GNUNET_SCHEDULER_add_now (&GNS_resolver_lookup_cancel_,
2238                                             rh);
2239     return;
2240   }
2241
2242   switch (rd[0].record_type)
2243   {
2244   case GNUNET_DNSPARSER_TYPE_CNAME:
2245     GNUNET_break_op (1 == rd_count); /* CNAME should be unique */
2246     recursive_cname_resolution (rh,
2247                                 &rd[0]);
2248     return;
2249   case GNUNET_GNSRECORD_TYPE_PKEY:
2250     GNUNET_break_op (1 == rd_count); /* PKEY should be unique */
2251     recursive_pkey_resolution (rh,
2252                                &rd[0]);
2253     return;
2254   default:
2255     if (GNUNET_OK ==
2256         recursive_gns2dns_resolution (rh,
2257                                       rd_count,
2258                                       rd))
2259       return;
2260     break;
2261   }
2262  fail:
2263   GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
2264               _("GNS lookup recursion failed (no delegation record found)\n"));
2265   fail_resolution (rh);
2266 }
2267
2268
2269 /**
2270  * Function called once the namestore has completed the request for
2271  * caching a block.
2272  *
2273  * @param cls closure with the `struct CacheOps`
2274  * @param success #GNUNET_OK on success
2275  * @param emsg error message
2276  */
2277 static void
2278 namecache_cache_continuation (void *cls,
2279                               int32_t success,
2280                               const char *emsg)
2281 {
2282   struct CacheOps *co = cls;
2283
2284   co->namecache_qe_cache = NULL;
2285   if (GNUNET_OK != success)
2286     GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
2287                 _("Failed to cache GNS resolution: %s\n"),
2288                 emsg);
2289   GNUNET_CONTAINER_DLL_remove (co_head,
2290                                co_tail,
2291                                co);
2292   GNUNET_free (co);
2293 }
2294
2295
2296 /**
2297  * Iterator called on each result obtained for a DHT
2298  * operation that expects a reply
2299  *
2300  * @param cls closure with the `struct GNS_ResolverHandle`
2301  * @param exp when will this value expire
2302  * @param key key of the result
2303  * @param get_path peers on reply path (or NULL if not recorded)
2304  *                 [0] = datastore's first neighbor, [length - 1] = local peer
2305  * @param get_path_length number of entries in @a get_path
2306  * @param put_path peers on the PUT path (or NULL if not recorded)
2307  *                 [0] = origin, [length - 1] = datastore
2308  * @param put_path_length number of entries in @a put_path
2309  * @param type type of the result
2310  * @param size number of bytes in data
2311  * @param data pointer to the result data
2312  */
2313 static void
2314 handle_dht_response (void *cls,
2315                      struct GNUNET_TIME_Absolute exp,
2316                      const struct GNUNET_HashCode *key,
2317                      const struct GNUNET_PeerIdentity *get_path,
2318                      unsigned int get_path_length,
2319                      const struct GNUNET_PeerIdentity *put_path,
2320                      unsigned int put_path_length,
2321                      enum GNUNET_BLOCK_Type type,
2322                      size_t size,
2323                      const void *data)
2324 {
2325   struct GNS_ResolverHandle *rh = cls;
2326   struct AuthorityChain *ac = rh->ac_tail;
2327   const struct GNUNET_GNSRECORD_Block *block;
2328   struct CacheOps *co;
2329
2330   (void) exp;
2331   (void) key;
2332   (void) get_path;
2333   (void) get_path_length;
2334   (void) put_path;
2335   (void) put_path_length;
2336   (void) type;
2337   GNUNET_DHT_get_stop (rh->get_handle);
2338   rh->get_handle = NULL;
2339   GNUNET_CONTAINER_heap_remove_node (rh->dht_heap_node);
2340   rh->dht_heap_node = NULL;
2341   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
2342               "Handling response from the DHT\n");
2343   if (size < sizeof (struct GNUNET_GNSRECORD_Block))
2344   {
2345     /* how did this pass DHT block validation!? */
2346     GNUNET_break (0);
2347     fail_resolution (rh);
2348     return;
2349   }
2350   block = data;
2351   if (size !=
2352       ntohl (block->purpose.size) +
2353       sizeof (struct GNUNET_CRYPTO_EcdsaPublicKey) +
2354       sizeof (struct GNUNET_CRYPTO_EcdsaSignature))
2355   {
2356     /* how did this pass DHT block validation!? */
2357     GNUNET_break (0);
2358     fail_resolution (rh);
2359     return;
2360   }
2361   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
2362               "Decrypting DHT block of size %u for `%s', expires %s\n",
2363               ntohl (block->purpose.size),
2364               rh->name,
2365               GNUNET_STRINGS_absolute_time_to_string (exp));
2366   if (GNUNET_OK !=
2367       GNUNET_GNSRECORD_block_decrypt (block,
2368                                       &ac->authority_info.gns_authority,
2369                                       ac->label,
2370                                       &handle_gns_resolution_result,
2371                                       rh))
2372   {
2373     GNUNET_break_op (0); /* block was ill-formed */
2374     fail_resolution (rh);
2375     return;
2376   }
2377   if (0 == GNUNET_TIME_absolute_get_remaining (GNUNET_TIME_absolute_ntoh (block->expiration_time)).rel_value_us)
2378   {
2379     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
2380                 "Received expired block from the DHT, will not cache it.\n");
2381     return;
2382   }
2383   if (GNUNET_YES == disable_cache)
2384     return;
2385   /* Cache well-formed blocks */
2386   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
2387               "Caching response from the DHT in namecache\n");
2388   co = GNUNET_new (struct CacheOps);
2389   co->namecache_qe_cache = GNUNET_NAMECACHE_block_cache (namecache_handle,
2390                                                          block,
2391                                                          &namecache_cache_continuation,
2392                                                          co);
2393   GNUNET_CONTAINER_DLL_insert (co_head,
2394                                co_tail,
2395                                co);
2396 }
2397
2398
2399 /**
2400  * Initiate a DHT query for a set of GNS records.
2401  *
2402  * @param rh resolution handle
2403  * @param query key to use in the DHT lookup
2404  */
2405 static void
2406 start_dht_request (struct GNS_ResolverHandle *rh,
2407                    const struct GNUNET_HashCode *query)
2408 {
2409   struct GNS_ResolverHandle *rx;
2410
2411   GNUNET_assert (NULL == rh->get_handle);
2412   rh->get_handle = GNUNET_DHT_get_start (dht_handle,
2413                                          GNUNET_BLOCK_TYPE_GNS_NAMERECORD,
2414                                          query,
2415                                          DHT_GNS_REPLICATION_LEVEL,
2416                                          GNUNET_DHT_RO_DEMULTIPLEX_EVERYWHERE,
2417                                          NULL, 0,
2418                                          &handle_dht_response, rh);
2419   rh->dht_heap_node = GNUNET_CONTAINER_heap_insert (dht_lookup_heap,
2420                                                     rh,
2421                                                     GNUNET_TIME_absolute_get ().abs_value_us);
2422   if (GNUNET_CONTAINER_heap_get_size (dht_lookup_heap) > max_allowed_background_queries)
2423   {
2424     /* fail longest-standing DHT request */
2425     rx = GNUNET_CONTAINER_heap_remove_root (dht_lookup_heap);
2426     rx->dht_heap_node = NULL;
2427     GNUNET_assert (NULL != rx);
2428     fail_resolution (rx);
2429   }
2430 }
2431
2432
2433 /**
2434  * Process a records that were decrypted from a block that we got from
2435  * the namecache.  Simply calls #handle_gns_resolution_result().
2436  *
2437  * @param cls closure with the `struct GNS_ResolverHandle`
2438  * @param rd_count number of entries in @a rd array
2439  * @param rd array of records with data to store
2440  */
2441 static void
2442 handle_gns_namecache_resolution_result (void *cls,
2443                                         unsigned int rd_count,
2444                                         const struct GNUNET_GNSRECORD_Data *rd)
2445 {
2446   struct GNS_ResolverHandle *rh = cls;
2447
2448   if (0 == rd_count)
2449     GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
2450                 _("GNS namecache returned empty result for `%s'\n"),
2451                 rh->name);
2452   handle_gns_resolution_result (rh,
2453                                 rd_count,
2454                                 rd);
2455 }
2456
2457
2458 /**
2459  * Process a record that was stored in the namecache.
2460  *
2461  * @param cls closure with the `struct GNS_ResolverHandle`
2462  * @param block block that was stored in the namecache
2463  */
2464 static void
2465 handle_namecache_block_response (void *cls,
2466                                  const struct GNUNET_GNSRECORD_Block *block)
2467 {
2468   struct GNS_ResolverHandle *rh = cls;
2469   struct AuthorityChain *ac = rh->ac_tail;
2470   const char *label = ac->label;
2471   const struct GNUNET_CRYPTO_EcdsaPublicKey *auth = &ac->authority_info.gns_authority;
2472   struct GNUNET_HashCode query;
2473
2474   GNUNET_assert (NULL != rh->namecache_qe);
2475   rh->namecache_qe = NULL;
2476   if ( ( (GNUNET_GNS_LO_DEFAULT == rh->options) ||
2477          ( (GNUNET_GNS_LO_LOCAL_MASTER == rh->options) &&
2478            (ac != rh->ac_head) ) ) &&
2479        ( (NULL == block) ||
2480          (0 == GNUNET_TIME_absolute_get_remaining (GNUNET_TIME_absolute_ntoh (block->expiration_time)).rel_value_us) ) )
2481   {
2482     /* namecache knows nothing; try DHT lookup */
2483     GNUNET_GNSRECORD_query_from_public_key (auth,
2484                                             label,
2485                                             &query);
2486     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
2487                 "Starting DHT lookup for `%s' in zone `%s' under key `%s'\n",
2488                 ac->label,
2489                 GNUNET_GNSRECORD_z2s (&ac->authority_info.gns_authority),
2490                 GNUNET_h2s (&query));
2491     start_dht_request (rh, &query);
2492     return;
2493   }
2494
2495   if ( (NULL == block) ||
2496        (0 == GNUNET_TIME_absolute_get_remaining (GNUNET_TIME_absolute_ntoh (block->expiration_time)).rel_value_us) )
2497   {
2498     /* DHT not permitted and no local result, fail */
2499     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
2500                 "Resolution failed for `%s' in zone %s (DHT lookup not permitted by configuration)\n",
2501                 ac->label,
2502                 GNUNET_GNSRECORD_z2s (&ac->authority_info.gns_authority));
2503     fail_resolution (rh);
2504     return;
2505   }
2506   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
2507               "Received result from namecache for label `%s'\n",
2508               ac->label);
2509
2510   if (GNUNET_OK !=
2511       GNUNET_GNSRECORD_block_decrypt (block,
2512                                       auth,
2513                                       label,
2514                                       &handle_gns_namecache_resolution_result,
2515                                       rh))
2516   {
2517     GNUNET_break_op (0); /* block was ill-formed */
2518     /* try DHT instead */
2519     GNUNET_GNSRECORD_query_from_public_key (auth,
2520                                             label,
2521                                             &query);
2522     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
2523                 "Starting DHT lookup for `%s' in zone `%s' under key `%s'\n",
2524                 ac->label,
2525                 GNUNET_GNSRECORD_z2s (&ac->authority_info.gns_authority),
2526                 GNUNET_h2s (&query));
2527     start_dht_request (rh, &query);
2528     return;
2529   }
2530 }
2531
2532
2533 /**
2534  * Lookup tail of our authority chain in the namecache.
2535  *
2536  * @param rh query we are processing
2537  */
2538 static void
2539 recursive_gns_resolution_namecache (struct GNS_ResolverHandle *rh)
2540 {
2541   struct AuthorityChain *ac = rh->ac_tail;
2542   struct GNUNET_HashCode query;
2543
2544   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
2545               "Starting GNS resolution for `%s' in zone %s\n",
2546               ac->label,
2547               GNUNET_GNSRECORD_z2s (&ac->authority_info.gns_authority));
2548   GNUNET_GNSRECORD_query_from_public_key (&ac->authority_info.gns_authority,
2549                                           ac->label,
2550                                           &query);
2551   if (GNUNET_YES != disable_cache)
2552   {
2553     rh->namecache_qe
2554       = GNUNET_NAMECACHE_lookup_block (namecache_handle,
2555                                        &query,
2556                                        &handle_namecache_block_response,
2557                                        rh);
2558     GNUNET_assert (NULL != rh->namecache_qe);
2559   }
2560   else
2561   {
2562     start_dht_request (rh,
2563                        &query);
2564   }
2565 }
2566
2567
2568 /**
2569  * Function called with the result from a revocation check.
2570  *
2571  * @param cls the `struct GNS_ResovlerHandle`
2572  * @param is_valid #GNUNET_YES if the zone was not yet revoked
2573  */
2574 static void
2575 handle_revocation_result (void *cls,
2576                           int is_valid)
2577 {
2578   struct GNS_ResolverHandle *rh = cls;
2579   struct AuthorityChain *ac = rh->ac_tail;
2580
2581   rh->rev_check = NULL;
2582   if (GNUNET_YES != is_valid)
2583   {
2584     GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
2585                 _("Zone %s was revoked, resolution fails\n"),
2586                 GNUNET_GNSRECORD_z2s (&ac->authority_info.gns_authority));
2587     fail_resolution (rh);
2588     return;
2589   }
2590   recursive_gns_resolution_namecache (rh);
2591 }
2592
2593
2594 /**
2595  * Perform revocation check on tail of our authority chain.
2596  *
2597  * @param rh query we are processing
2598  */
2599 static void
2600 recursive_gns_resolution_revocation (struct GNS_ResolverHandle *rh)
2601 {
2602   struct AuthorityChain *ac = rh->ac_tail;
2603
2604   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
2605               "Starting revocation check for zone %s\n",
2606               GNUNET_GNSRECORD_z2s (&ac->authority_info.gns_authority));
2607   rh->rev_check = GNUNET_REVOCATION_query (cfg,
2608                                            &ac->authority_info.gns_authority,
2609                                            &handle_revocation_result,
2610                                            rh);
2611   GNUNET_assert (NULL != rh->rev_check);
2612 }
2613
2614
2615 /**
2616  * Task scheduled to continue with the resolution process.
2617  *
2618  * @param cls the `struct GNS_ResolverHandle` of the resolution
2619  */
2620 static void
2621 recursive_resolution (void *cls)
2622 {
2623   struct GNS_ResolverHandle *rh = cls;
2624
2625   rh->task_id = NULL;
2626   if (MAX_RECURSION < rh->loop_limiter++)
2627   {
2628     GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
2629                 "Encountered unbounded recursion resolving `%s'\n",
2630                 rh->name);
2631     fail_resolution (rh);
2632     return;
2633   }
2634   if (GNUNET_YES == rh->ac_tail->gns_authority)
2635     recursive_gns_resolution_revocation (rh);
2636   else
2637     recursive_dns_resolution (rh);
2638 }
2639
2640
2641 /**
2642  * Begin the resolution process from 'name', starting with
2643  * the identification of the zone specified by 'name'.
2644  *
2645  * @param cls the `struct GNS_ResolverHandle`
2646  */
2647 static void
2648 start_resolver_lookup (void *cls)
2649 {
2650   struct GNS_ResolverHandle *rh = cls;
2651   struct AuthorityChain *ac;
2652   struct in_addr v4;
2653   struct in6_addr v6;
2654
2655   rh->task_id = NULL;
2656   if (1 == inet_pton (AF_INET,
2657                       rh->name,
2658                       &v4))
2659   {
2660     /* name is IPv4 address, pretend it's an A record */
2661     struct GNUNET_GNSRECORD_Data rd;
2662
2663     rd.data = &v4;
2664     rd.data_size = sizeof (v4);
2665     rd.expiration_time = UINT64_MAX;
2666     rd.record_type = GNUNET_DNSPARSER_TYPE_A;
2667     rd.flags = 0;
2668     rh->proc (rh->proc_cls,
2669               1,
2670               &rd);
2671     GNUNET_assert (NULL == rh->task_id);
2672     rh->task_id = GNUNET_SCHEDULER_add_now (&GNS_resolver_lookup_cancel_,
2673                                             rh);
2674     return;
2675   }
2676   if (1 == inet_pton (AF_INET6,
2677                       rh->name,
2678                       &v6))
2679   {
2680     /* name is IPv6 address, pretend it's an AAAA record */
2681     struct GNUNET_GNSRECORD_Data rd;
2682
2683     rd.data = &v6;
2684     rd.data_size = sizeof (v6);
2685     rd.expiration_time = UINT64_MAX;
2686     rd.record_type = GNUNET_DNSPARSER_TYPE_AAAA;
2687     rd.flags = 0;
2688     rh->proc (rh->proc_cls,
2689               1,
2690               &rd);
2691     GNUNET_assert (NULL == rh->task_id);
2692     rh->task_id = GNUNET_SCHEDULER_add_now (&GNS_resolver_lookup_cancel_,
2693                                             rh);
2694     return;
2695   }
2696
2697   ac = GNUNET_new (struct AuthorityChain);
2698   ac->rh = rh;
2699   ac->label = resolver_lookup_get_next_label (rh);
2700   if (NULL == ac->label)
2701     /* name was just the "TLD", so we default to label
2702        #GNUNET_GNS_EMPTY_LABEL_AT */
2703     ac->label = GNUNET_strdup (GNUNET_GNS_EMPTY_LABEL_AT);
2704   ac->gns_authority = GNUNET_YES;
2705   ac->authority_info.gns_authority = rh->authority_zone;
2706   GNUNET_CONTAINER_DLL_insert_tail (rh->ac_head,
2707                                     rh->ac_tail,
2708                                     ac);
2709   rh->task_id = GNUNET_SCHEDULER_add_now (&recursive_resolution,
2710                                           rh);
2711 }
2712
2713
2714 /**
2715  * Lookup of a record in a specific zone calls lookup result processor
2716  * on result.
2717  *
2718  * @param zone the zone to perform the lookup in
2719  * @param record_type the record type to look up
2720  * @param name the name to look up
2721  * @param options local options to control local lookup
2722  * @param proc the processor to call on result
2723  * @param proc_cls the closure to pass to @a proc
2724  * @return handle to cancel operation
2725  */
2726 struct GNS_ResolverHandle *
2727 GNS_resolver_lookup (const struct GNUNET_CRYPTO_EcdsaPublicKey *zone,
2728                      uint32_t record_type,
2729                      const char *name,
2730                      enum GNUNET_GNS_LocalOptions options,
2731                      GNS_ResultProcessor proc,
2732                      void *proc_cls)
2733 {
2734   struct GNS_ResolverHandle *rh;
2735
2736   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
2737               "Starting lookup for `%s'\n",
2738               name);
2739   rh = GNUNET_new (struct GNS_ResolverHandle);
2740   GNUNET_CONTAINER_DLL_insert (rlh_head,
2741                                rlh_tail,
2742                                rh);
2743   rh->authority_zone = *zone;
2744   rh->proc = proc;
2745   rh->proc_cls = proc_cls;
2746   rh->options = options;
2747   rh->record_type = record_type;
2748   rh->name = GNUNET_strdup (name);
2749   rh->name_resolution_pos = strlen (name);
2750   rh->task_id = GNUNET_SCHEDULER_add_now (&start_resolver_lookup,
2751                                           rh);
2752   return rh;
2753 }
2754
2755
2756 /**
2757  * Cancel active resolution (i.e. client disconnected).
2758  *
2759  * @param rh resolution to abort
2760  */
2761 void
2762 GNS_resolver_lookup_cancel (struct GNS_ResolverHandle *rh)
2763 {
2764   struct DnsResult *dr;
2765   struct AuthorityChain *ac;
2766   struct VpnContext *vpn_ctx;
2767
2768   GNUNET_CONTAINER_DLL_remove (rlh_head,
2769                                rlh_tail,
2770                                rh);
2771   if (NULL != rh->dns_request)
2772   {
2773     GNUNET_DNSSTUB_resolve_cancel (rh->dns_request);
2774     rh->dns_request = NULL;
2775   }
2776   while (NULL != (ac = rh->ac_head))
2777   {
2778     GNUNET_CONTAINER_DLL_remove (rh->ac_head,
2779                                  rh->ac_tail,
2780                                  ac);
2781     if (GNUNET_NO == ac->gns_authority)
2782     {
2783       struct Gns2DnsPending *gp;
2784
2785       while (NULL != (gp = ac->authority_info.dns_authority.gp_head))
2786       {
2787         GNUNET_CONTAINER_DLL_remove (ac->authority_info.dns_authority.gp_head,
2788                                      ac->authority_info.dns_authority.gp_tail,
2789                                      gp);
2790         if (NULL != gp->rh)
2791         {
2792           /* rh->g2dc->rh is NOT in the DLL yet, so to enable us
2793              using GNS_resolver_lookup_cancel here, we need to
2794              add it first... */
2795           GNUNET_CONTAINER_DLL_insert (rlh_head,
2796                                        rlh_tail,
2797                                        gp->rh);
2798           GNUNET_assert (NULL == gp->rh->task_id);
2799           gp->rh->task_id = GNUNET_SCHEDULER_add_now (&GNS_resolver_lookup_cancel_,
2800                                                       gp->rh);
2801           gp->rh = NULL;
2802         }
2803         if (NULL != gp->dns_rh)
2804         {
2805           GNUNET_RESOLVER_request_cancel (gp->dns_rh);
2806           gp->dns_rh = NULL;
2807         }
2808         GNUNET_free (gp);
2809       }
2810       GNUNET_DNSSTUB_stop (ac->authority_info.dns_authority.dns_handle);
2811     }
2812     GNUNET_free (ac->label);
2813     GNUNET_free (ac);
2814   }
2815   if (NULL != rh->task_id)
2816   {
2817     GNUNET_SCHEDULER_cancel (rh->task_id);
2818     rh->task_id = NULL;
2819   }
2820   if (NULL != rh->get_handle)
2821   {
2822     GNUNET_DHT_get_stop (rh->get_handle);
2823     rh->get_handle = NULL;
2824   }
2825   if (NULL != rh->dht_heap_node)
2826   {
2827     GNUNET_CONTAINER_heap_remove_node (rh->dht_heap_node);
2828     rh->dht_heap_node = NULL;
2829   }
2830   if (NULL != (vpn_ctx = rh->vpn_ctx))
2831   {
2832     GNUNET_VPN_cancel_request (vpn_ctx->vpn_request);
2833     GNUNET_free (vpn_ctx->rd_data);
2834     GNUNET_free (vpn_ctx);
2835   }
2836   if (NULL != rh->namecache_qe)
2837   {
2838     GNUNET_NAMECACHE_cancel (rh->namecache_qe);
2839     rh->namecache_qe = NULL;
2840   }
2841   if (NULL != rh->rev_check)
2842   {
2843     GNUNET_REVOCATION_query_cancel (rh->rev_check);
2844     rh->rev_check = NULL;
2845   }
2846   if (NULL != rh->std_resolve)
2847   {
2848     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
2849                 "Canceling standard DNS resolution\n");
2850     GNUNET_RESOLVER_request_cancel (rh->std_resolve);
2851     rh->std_resolve = NULL;
2852   }
2853   while (NULL != (dr = rh->dns_result_head))
2854   {
2855     GNUNET_CONTAINER_DLL_remove (rh->dns_result_head,
2856                                  rh->dns_result_tail,
2857                                  dr);
2858     GNUNET_free (dr);
2859   }
2860   GNUNET_free_non_null (rh->leho);
2861   GNUNET_free (rh->name);
2862   GNUNET_free (rh);
2863 }
2864
2865
2866 /* ***************** Resolver initialization ********************* */
2867
2868
2869 /**
2870  * Initialize the resolver
2871  *
2872  * @param nc the namecache handle
2873  * @param dht the dht handle
2874  * @param c configuration handle
2875  * @param max_bg_queries maximum number of parallel background queries in dht
2876  */
2877 void
2878 GNS_resolver_init (struct GNUNET_NAMECACHE_Handle *nc,
2879                    struct GNUNET_DHT_Handle *dht,
2880                    const struct GNUNET_CONFIGURATION_Handle *c,
2881                    unsigned long long max_bg_queries)
2882 {
2883   cfg = c;
2884   namecache_handle = nc;
2885   dht_handle = dht;
2886   dht_lookup_heap =
2887     GNUNET_CONTAINER_heap_create (GNUNET_CONTAINER_HEAP_ORDER_MIN);
2888   max_allowed_background_queries = max_bg_queries;
2889   disable_cache = GNUNET_CONFIGURATION_get_value_yesno (cfg,
2890                                                         "namecache",
2891                                                         "DISABLE");
2892   if (GNUNET_YES == disable_cache)
2893     GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
2894                 "Namecache disabled\n");
2895   vpn_handle = GNUNET_VPN_connect (cfg);
2896 }
2897
2898
2899 /**
2900  * Shutdown resolver
2901  */
2902 void
2903 GNS_resolver_done ()
2904 {
2905   struct GNS_ResolverHandle *rh;
2906   struct CacheOps *co;
2907
2908   /* abort active resolutions */
2909   while (NULL != (rh = rlh_head))
2910   {
2911     rh->proc (rh->proc_cls,
2912               0,
2913               NULL);
2914     GNS_resolver_lookup_cancel (rh);
2915   }
2916   while (NULL != (co = co_head))
2917   {
2918     GNUNET_CONTAINER_DLL_remove (co_head,
2919                                  co_tail,
2920                                  co);
2921     GNUNET_NAMECACHE_cancel (co->namecache_qe_cache);
2922     GNUNET_free (co);
2923   }
2924   GNUNET_CONTAINER_heap_destroy (dht_lookup_heap);
2925   dht_lookup_heap = NULL;
2926   GNUNET_VPN_disconnect (vpn_handle);
2927   vpn_handle = NULL;
2928   dht_handle = NULL;
2929   namecache_handle = NULL;
2930 }
2931
2932
2933 /* end of gnunet-service-gns_resolver.c */