src/gns/gnunet-service-gns.c

   1 /*
   2      This file is part of GNUnet.
   3      (C) 2011-2013 Christian Grothoff (and other contributing authors)
   4
   5      GNUnet is free software; you can redistribute it and/or modify
   6      it under the terms of the GNU General Public License as published
   7      by the Free Software Foundation; either version 3, or (at your
   8      option) any later version.
   9
  10      GNUnet is distributed in the hope that it will be useful, but
  11      WITHOUT ANY WARRANTY; without even the implied warranty of
  12      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13      General Public License for more details.
  14
  15      You should have received a copy of the GNU General Public License
  16      along with GNUnet; see the file COPYING.  If not, write to the
  17      Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18      Boston, MA 02111-1307, USA.
  19 */
  20 /**
  21  * @file gns/gnunet-service-gns.c
  22  * @brief GNU Name System (main service)
  23  * @author Martin Schanzenbach
  24  * @author Christian Grothoff
  25  */
  26 #include "platform.h"
  27 #include "gnunet_util_lib.h"
  28 #include "gnunet_dns_service.h"
  29 #include "gnunet_dnsparser_lib.h"
  30 #include "gnunet_dht_service.h"
  31 #include "gnunet_namestore_service.h"
  32 #include "gnunet_gns_service.h"
  33 #include "gnunet_statistics_service.h"
  34 #include "gns.h"
  35 #include "gnunet-service-gns_resolver.h"
  36 #include "gnunet-service-gns_shorten.h"
  37 #include "gnunet-service-gns_interceptor.h"
  38 #include "gnunet_protocols.h"
  39
  40 /**
  41  * The initial interval in milliseconds btween puts in
  42  * a zone iteration
  43  */
  44 #define INITIAL_PUT_INTERVAL GNUNET_TIME_UNIT_MILLISECONDS
  45
  46 /**
  47  * The upper bound for the zone iteration interval in milliseconds
  48  */
  49 #define MINIMUM_ZONE_ITERATION_INTERVAL GNUNET_TIME_UNIT_SECONDS
  50
  51 /**
  52  * The default put interval for the zone iteration. In case
  53  * no option is found
  54  */
  55 #define DEFAULT_ZONE_PUBLISH_TIME_WINDOW GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_HOURS, 4)
  56
  57 /**
  58  * The factor the current zone iteration interval is divided by for each
  59  * additional new record
  60  */
  61 #define LATE_ITERATION_SPEEDUP_FACTOR 2
  62
  63 /**
  64  * How long until a DHT PUT attempt should time out?
  65  */
  66 #define DHT_OPERATION_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 60)
  67
  68 /**
  69  * What replication level do we use for DHT PUT operations?
  70  */
  71 #define DHT_GNS_REPLICATION_LEVEL 5
  72
  73
  74 /**
  75  * Handle to a lookup operation from api
  76  */
  77 struct ClientLookupHandle
  78 {
  79
  80   /**
  81    * We keep these in a DLL.
  82    */
  83   struct ClientLookupHandle *next;
  84
  85   /**
  86    * We keep these in a DLL.
  87    */
  88   struct ClientLookupHandle *prev;
  89
  90   /**
  91    * Handle to the requesting client
  92    */
  93   struct GNUNET_SERVER_Client *client;
  94
  95   /**
  96    * Active handle for the lookup.
  97    */
  98   struct GNS_ResolverHandle *lookup;
  99
 100   /**
 101    * request id
 102    */
 103   uint32_t request_id;
 104
 105 };
 106
 107
 108 /**
 109  * Our handle to the DHT
 110  */
 111 static struct GNUNET_DHT_Handle *dht_handle;
 112
 113 /**
 114  * Active DHT put operation (or NULL)
 115  */
 116 static struct GNUNET_DHT_PutHandle *active_put;
 117
 118 /**
 119  * Our handle to the namestore service
 120  */
 121 static struct GNUNET_NAMESTORE_Handle *namestore_handle;
 122
 123 /**
 124  * Handle to iterate over our authoritative zone in namestore
 125  */
 126 static struct GNUNET_NAMESTORE_ZoneIterator *namestore_iter;
 127
 128 /**
 129  * Our notification context.
 130  */
 131 static struct GNUNET_SERVER_NotificationContext *nc;
 132
 133 /**
 134  * Head of the DLL.
 135  */
 136 static struct ClientLookupHandle *clh_head;
 137
 138 /**
 139  * Tail of the DLL.
 140  */
 141 static struct ClientLookupHandle *clh_tail;
 142
 143 /**
 144  * Useful for zone update for DHT put
 145  */
 146 static unsigned long long num_public_records;
 147
 148 /**
 149  * Last seen record count
 150  */
 151 static unsigned long long last_num_public_records;
 152
 153 /**
 154  * Zone iteration PUT interval.
 155  */
 156 static struct GNUNET_TIME_Relative put_interval;
 157
 158 /**
 159  * Time window for zone iteration
 160  */
 161 static struct GNUNET_TIME_Relative zone_publish_time_window;
 162
 163 /**
 164  * zone publish task
 165  */
 166 static GNUNET_SCHEDULER_TaskIdentifier zone_publish_task;
 167
 168 /**
 169  * #GNUNET_YES if zone has never been published before
 170  */
 171 static int first_zone_iteration;
 172
 173 /**
 174  * The lookup timeout
 175  */
 176 static struct GNUNET_TIME_Relative default_lookup_timeout;
 177
 178 /**
 179  * #GNUNET_YES if ipv6 is supported
 180  */
 181 static int v6_enabled;
 182
 183 /**
 184  * #GNUNET_YES if ipv4 is supported
 185  */
 186 static int v4_enabled;
 187
 188 /**
 189  * Handle to the statistics service
 190  */
 191 static struct GNUNET_STATISTICS_Handle *statistics;
 192
 193
 194 /**
 195  * Task run during shutdown.
 196  *
 197  * @param cls unused
 198  * @param tc unused
 199  */
 200 static void
 201 shutdown_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
 202 {
 203   struct ClientLookupHandle *clh;
 204
 205   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 206               "Shutting down!\n");
 207   GNUNET_SERVER_notification_context_destroy (nc);
 208   while (NULL != (clh = clh_head))
 209   {
 210     GNUNET_SERVER_client_set_user_context (clh->client, NULL);
 211     GNS_resolver_lookup_cancel (clh->lookup);
 212     GNUNET_CONTAINER_DLL_remove (clh_head, clh_tail, clh);
 213     GNUNET_free (clh);
 214   }
 215
 216   GNS_interceptor_done ();
 217   GNS_resolver_done ();
 218   GNS_shorten_done ();
 219   if (NULL != statistics)
 220   {
 221     GNUNET_STATISTICS_destroy (statistics, GNUNET_NO);
 222     statistics = NULL;
 223   }
 224   if (GNUNET_SCHEDULER_NO_TASK != zone_publish_task)
 225   {
 226     GNUNET_SCHEDULER_cancel (zone_publish_task);
 227     zone_publish_task = GNUNET_SCHEDULER_NO_TASK;
 228   }
 229   if (NULL != namestore_iter)
 230   {
 231     GNUNET_NAMESTORE_zone_iteration_stop (namestore_iter);
 232     namestore_iter = NULL;
 233   }
 234   if (NULL != namestore_handle)
 235   {
 236     GNUNET_NAMESTORE_disconnect (namestore_handle);
 237     namestore_handle = NULL;
 238   }
 239   if (NULL != active_put)
 240   {
 241     GNUNET_DHT_put_cancel (active_put);
 242     active_put = NULL;
 243   }
 244   if (NULL != dht_handle)
 245   {
 246     GNUNET_DHT_disconnect (dht_handle);
 247     dht_handle = NULL;
 248   }
 249 }
 250
 251
 252 /**
 253  * Method called periodically that triggers iteration over authoritative records
 254  *
 255  * @param cls closure
 256  * @param tc task context
 257  */
 258 static void
 259 publish_zone_dht_next (void *cls,
 260                        const struct GNUNET_SCHEDULER_TaskContext *tc)
 261 {
 262   zone_publish_task = GNUNET_SCHEDULER_NO_TASK;
 263   GNUNET_NAMESTORE_zone_iterator_next (namestore_iter);
 264 }
 265
 266
 267 /**
 268  * Periodically iterate over our zone and store everything in dht
 269  *
 270  * @param cls NULL
 271  * @param tc task context
 272  */
 273 static void
 274 publish_zone_dht_start (void *cls,
 275                         const struct GNUNET_SCHEDULER_TaskContext *tc);
 276
 277
 278 /**
 279  * Continuation called from DHT once the PUT operation is done.
 280  *
 281  * @param cls closure, NULL
 282  * @param success #GNUNET_OK on success
 283  */
 284 static void
 285 dht_put_continuation (void *cls,
 286                       int success)
 287 {
 288   struct GNUNET_TIME_Relative next_put_interval;
 289
 290   active_put = NULL;
 291   num_public_records++;
 292   if ( (num_public_records > last_num_public_records) &&
 293        (GNUNET_NO == first_zone_iteration) )
 294   {
 295     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 296                 "Last record count was lower than current record count.  Reducing interval.\n");
 297     put_interval = GNUNET_TIME_relative_divide (zone_publish_time_window,
 298                                                 num_public_records);
 299     next_put_interval = GNUNET_TIME_relative_divide (put_interval,
 300                                                      LATE_ITERATION_SPEEDUP_FACTOR);
 301   }
 302   else
 303     next_put_interval = put_interval;
 304
 305   GNUNET_STATISTICS_set (statistics,
 306                          "Current zone iteration interval (ms)",
 307                          next_put_interval.rel_value_us / 1000LL,
 308                          GNUNET_NO);
 309   zone_publish_task = GNUNET_SCHEDULER_add_delayed (next_put_interval,
 310                                                     &publish_zone_dht_next,
 311                                                     NULL);
 312 }
 313
 314
 315 /**
 316  * Function used to put all records successively into the DHT.
 317  *
 318  * @param cls the closure (NULL)
 319  * @param key the private key of the authority (ours)
 320  * @param name the name of the records, NULL once the iteration is done
 321  * @param rd_count the number of records in @a rd
 322  * @param rd the record data
 323  */
 324 static void
 325 put_gns_record (void *cls,
 326                 const struct GNUNET_CRYPTO_EccPrivateKey *key,
 327                 const char *name,
 328                 unsigned int rd_count,
 329                 const struct GNUNET_NAMESTORE_RecordData *rd)
 330 {
 331   struct GNUNET_NAMESTORE_Block *block;
 332   struct GNUNET_HashCode query;
 333   struct GNUNET_TIME_Absolute expire;
 334   struct GNUNET_TIME_Absolute now;
 335   size_t block_size;
 336   struct GNUNET_NAMESTORE_RecordData rd_public[rd_count];
 337   unsigned int rd_public_count;
 338   unsigned int i;
 339
 340   if (NULL == name)
 341   {
 342     /* we're done with one iteration, calculate when to do the next one */
 343     namestore_iter = NULL;
 344     last_num_public_records = num_public_records;
 345     first_zone_iteration = GNUNET_NO;
 346     if (0 == num_public_records)
 347     {
 348       /**
 349        * If no records are known (startup) or none present
 350        * we can safely set the interval to the value for a single
 351        * record
 352        */
 353       put_interval = zone_publish_time_window;
 354       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG | GNUNET_ERROR_TYPE_BULK,
 355                   "No records in namestore database.\n");
 356     }
 357     else
 358     {
 359       put_interval = GNUNET_TIME_relative_divide (zone_publish_time_window,
 360                                                   num_public_records);
 361     }
 362     put_interval = GNUNET_TIME_relative_max (MINIMUM_ZONE_ITERATION_INTERVAL,
 363                                              put_interval);
 364
 365     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 366                 "Zone iteration finished. Adjusted zone iteration interval to %s\n",
 367                 GNUNET_STRINGS_relative_time_to_string (put_interval, GNUNET_YES));
 368     GNUNET_STATISTICS_set (statistics,
 369                            "Current zone iteration interval (in ms)",
 370                            put_interval.rel_value_us / 1000LL,
 371                            GNUNET_NO);
 372     GNUNET_STATISTICS_update (statistics,
 373                               "Number of zone iterations",
 374                               1,
 375                               GNUNET_NO);
 376     GNUNET_STATISTICS_set (statistics,
 377                            "Number of public records in DHT",
 378                            last_num_public_records,
 379                            GNUNET_NO);
 380     if (0 == num_public_records)
 381       zone_publish_task = GNUNET_SCHEDULER_add_delayed (put_interval,
 382                                                         &publish_zone_dht_start,
 383                                                         NULL);
 384     else
 385       zone_publish_task = GNUNET_SCHEDULER_add_now (&publish_zone_dht_start,
 386                                                     NULL);
 387     return;
 388   }
 389
 390   /* filter out records that are not public, and convert to
 391      absolute expiration time. */
 392   rd_public_count = 0;
 393   now = GNUNET_TIME_absolute_get ();
 394   for (i=0;i<rd_count;i++)
 395     if (0 == (rd[i].flags & (GNUNET_NAMESTORE_RF_PRIVATE |
 396                              GNUNET_NAMESTORE_RF_PENDING)))
 397     {
 398       rd_public[rd_public_count] = rd[i];
 399       if (0 != (rd[i].flags & GNUNET_NAMESTORE_RF_RELATIVE_EXPIRATION))
 400       {
 401         rd_public[rd_public_count].flags &= ~GNUNET_NAMESTORE_RF_RELATIVE_EXPIRATION;
 402         rd_public[rd_public_count].expiration_time += now.abs_value_us;
 403       }
 404       rd_public_count++;
 405     }
 406
 407   /* We got a set of records to publish */
 408   if (0 == rd_public_count)
 409   {
 410     zone_publish_task = GNUNET_SCHEDULER_add_now (&publish_zone_dht_next,
 411                                                    NULL);
 412     return;
 413   }
 414   expire = GNUNET_NAMESTORE_record_get_expiration_time (rd_public_count,
 415                                                         rd_public);
 416   block = GNUNET_NAMESTORE_block_create (key,
 417                                          expire,
 418                                          name,
 419                                          rd_public,
 420                                          rd_public_count);
 421   block_size = ntohl (block->purpose.size)
 422     + sizeof (struct GNUNET_CRYPTO_EccSignature)
 423     + sizeof (struct GNUNET_CRYPTO_EccPublicSignKey);
 424   GNUNET_NAMESTORE_query_from_private_key (key,
 425                                            name,
 426                                            &query);
 427
 428   active_put = GNUNET_DHT_put (dht_handle, &query,
 429                                DHT_GNS_REPLICATION_LEVEL,
 430                                GNUNET_DHT_RO_DEMULTIPLEX_EVERYWHERE,
 431                                GNUNET_BLOCK_TYPE_GNS_NAMERECORD,
 432                                block_size,
 433                                block,
 434                                expire,
 435                                DHT_OPERATION_TIMEOUT,
 436                                &dht_put_continuation,
 437                                NULL);
 438   if (NULL == active_put)
 439   {
 440     GNUNET_break (0);
 441     dht_put_continuation (NULL, GNUNET_NO);
 442   }
 443   GNUNET_free (block);
 444 }
 445
 446
 447 /**
 448  * Periodically iterate over our zone and store everything in dht
 449  *
 450  * @param cls NULL
 451  * @param tc task context
 452  */
 453 static void
 454 publish_zone_dht_start (void *cls,
 455                         const struct GNUNET_SCHEDULER_TaskContext *tc)
 456 {
 457   zone_publish_task = GNUNET_SCHEDULER_NO_TASK;
 458
 459   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 460               "Scheduling DHT zone update!\n");
 461   /* start counting again */
 462   num_public_records = 0;
 463   namestore_iter = GNUNET_NAMESTORE_zone_iteration_start (namestore_handle,
 464                                                           NULL, /* All zones */
 465                                                           &put_gns_record,
 466                                                           NULL);
 467 }
 468
 469
 470 /* END DHT ZONE PROPAGATION */
 471
 472
 473 /**
 474  * Reply to client with the result from our lookup.
 475  *
 476  * @param cls the closure (our client lookup handle)
 477  * @param rd_count the number of records in @a rd
 478  * @param rd the record data
 479  */
 480 static void
 481 send_lookup_response (void* cls,
 482                       uint32_t rd_count,
 483                       const struct GNUNET_NAMESTORE_RecordData *rd)
 484 {
 485   struct ClientLookupHandle *clh = cls;
 486   struct GNUNET_GNS_ClientLookupResultMessage *rmsg;
 487   size_t len;
 488
 489   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 490               "Sending `%s' message with %d results\n",
 491               "LOOKUP_RESULT",
 492               rd_count);
 493
 494   len = GNUNET_NAMESTORE_records_get_size (rd_count, rd);
 495   rmsg = GNUNET_malloc (len + sizeof (struct GNUNET_GNS_ClientLookupResultMessage));
 496   rmsg->header.type = htons (GNUNET_MESSAGE_TYPE_GNS_LOOKUP_RESULT);
 497   rmsg->header.size = htons (len + sizeof(struct GNUNET_GNS_ClientLookupResultMessage));
 498   rmsg->id = clh->request_id;
 499   rmsg->rd_count = htonl (rd_count);
 500   GNUNET_NAMESTORE_records_serialize (rd_count, rd, len,
 501                                       (char*) &rmsg[1]);
 502   GNUNET_SERVER_notification_context_unicast (nc,
 503                                               clh->client,
 504                                               &rmsg->header,
 505                                               GNUNET_NO);
 506   GNUNET_free (rmsg);
 507   GNUNET_SERVER_receive_done (clh->client,
 508                               GNUNET_OK);
 509   GNUNET_CONTAINER_DLL_remove (clh_head, clh_tail, clh);
 510   GNUNET_SERVER_client_set_user_context (clh->client, NULL);
 511   GNUNET_free (clh);
 512   GNUNET_STATISTICS_update (statistics,
 513                             "Completed lookups", 1,
 514                             GNUNET_NO);
 515   GNUNET_STATISTICS_update (statistics,
 516                             "Records resolved",
 517                             rd_count,
 518                             GNUNET_NO);
 519 }
 520
 521
 522 /**
 523  * Handle lookup requests from client
 524  *
 525  * @param cls the closure
 526  * @param client the client
 527  * @param message the message
 528  */
 529 static void
 530 handle_lookup (void *cls,
 531                struct GNUNET_SERVER_Client *client,
 532                const struct GNUNET_MessageHeader *message)
 533 {
 534   char name[GNUNET_DNSPARSER_MAX_NAME_LENGTH + 1];
 535   struct ClientLookupHandle *clh;
 536   char *nameptr = name;
 537   const char *utf_in;
 538   const struct GNUNET_CRYPTO_EccPrivateKey *key;
 539   uint16_t msg_size;
 540   const struct GNUNET_GNS_ClientLookupMessage *sh_msg;
 541
 542   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 543               "Received `%s' message\n",
 544               "LOOKUP");
 545   msg_size = ntohs (message->size);
 546   if (msg_size < sizeof (struct GNUNET_GNS_ClientLookupMessage))
 547   {
 548     GNUNET_break (0);
 549     GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
 550     return;
 551   }
 552   sh_msg = (const struct GNUNET_GNS_ClientLookupMessage *) message;
 553   GNUNET_SERVER_notification_context_add (nc, client);
 554   if (GNUNET_YES == ntohl (sh_msg->have_key))
 555     key = &sh_msg->shorten_key;
 556   else
 557     key = NULL;
 558   utf_in = (const char *) &sh_msg[1];
 559   if ( ('\0' != utf_in[msg_size - sizeof (struct GNUNET_GNS_ClientLookupMessage) - 1]) ||
 560        (strlen (utf_in) > GNUNET_DNSPARSER_MAX_NAME_LENGTH) )
 561   {
 562     GNUNET_break (0);
 563     GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
 564     return;
 565   }
 566   GNUNET_STRINGS_utf8_tolower (utf_in, &nameptr);
 567
 568   clh = GNUNET_new (struct ClientLookupHandle);
 569   GNUNET_SERVER_client_set_user_context (client, clh);
 570   GNUNET_CONTAINER_DLL_insert (clh_head, clh_tail, clh);
 571   clh->client = client;
 572   clh->request_id = sh_msg->id;
 573   if ( (GNUNET_DNSPARSER_TYPE_A == ntohl (sh_msg->type)) &&
 574        (GNUNET_OK != v4_enabled) )
 575   {
 576     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 577                 "LOOKUP: Query for A record but AF_INET not supported!");
 578     send_lookup_response (clh, 0, NULL);
 579     return;
 580   }
 581   if ( (GNUNET_DNSPARSER_TYPE_AAAA == ntohl (sh_msg->type)) &&
 582        (GNUNET_OK != v6_enabled) )
 583   {
 584     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 585                 "LOOKUP: Query for AAAA record but AF_INET6 not supported!");
 586     send_lookup_response (clh, 0, NULL);
 587     return;
 588   }
 589   clh->lookup = GNS_resolver_lookup (&sh_msg->zone,
 590                                      ntohl (sh_msg->type),
 591                                      name,
 592                                      key,
 593                                      ntohl (sh_msg->only_cached),
 594                                      &send_lookup_response, clh);
 595   GNUNET_STATISTICS_update (statistics,
 596                             "Lookup attempts",
 597                             1, GNUNET_NO);
 598 }
 599
 600
 601 /**
 602  * One of our clients disconnected, clean up after it.
 603  *
 604  * @param cls NULL
 605  * @param client the client that disconnected
 606  */
 607 static void
 608 notify_client_disconnect (void *cls,
 609                           struct GNUNET_SERVER_Client *client)
 610 {
 611   struct ClientLookupHandle *clh;
 612
 613   if (NULL == client)
 614     return;
 615   clh = GNUNET_SERVER_client_get_user_context (client, struct ClientLookupHandle);
 616   if (NULL == clh)
 617     return;
 618   GNS_resolver_lookup_cancel (clh->lookup);
 619   GNUNET_CONTAINER_DLL_remove (clh_head, clh_tail, clh);
 620   GNUNET_free (clh);
 621 }
 622
 623
 624 /**
 625  * Process GNS requests.
 626  *
 627  * @param cls closure
 628  * @param server the initialized server
 629  * @param c configuration to use
 630  */
 631 static void
 632 run (void *cls, struct GNUNET_SERVER_Handle *server,
 633      const struct GNUNET_CONFIGURATION_Handle *c)
 634 {
 635   static const struct GNUNET_SERVER_MessageHandler handlers[] = {
 636     { &handle_lookup, NULL, GNUNET_MESSAGE_TYPE_GNS_LOOKUP, 0},
 637     {NULL, NULL, 0, 0}
 638   };
 639   struct GNUNET_CRYPTO_EccPublicSignKey dns_root;
 640   unsigned long long max_parallel_bg_queries = 0;
 641   char *dns_root_name;
 642
 643   v6_enabled = GNUNET_NETWORK_test_pf (PF_INET6);
 644   v4_enabled = GNUNET_NETWORK_test_pf (PF_INET);
 645
 646   namestore_handle = GNUNET_NAMESTORE_connect (c);
 647   if (NULL == namestore_handle)
 648   {
 649     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
 650                 _("Failed to connect to the namestore!\n"));
 651     GNUNET_SCHEDULER_shutdown ();
 652     return;
 653   }
 654
 655   put_interval = INITIAL_PUT_INTERVAL;
 656   zone_publish_time_window = DEFAULT_ZONE_PUBLISH_TIME_WINDOW;
 657
 658   if (GNUNET_OK ==
 659       GNUNET_CONFIGURATION_get_value_time (c, "gns",
 660                                            "ZONE_PUBLISH_TIME_WINDOW",
 661                                            &zone_publish_time_window))
 662   {
 663     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 664                 "Time window for zone iteration: %s\n",
 665                 GNUNET_STRINGS_relative_time_to_string (zone_publish_time_window, GNUNET_YES));
 666   }
 667   if (GNUNET_OK ==
 668       GNUNET_CONFIGURATION_get_value_number (c, "gns",
 669                                             "MAX_PARALLEL_BACKGROUND_QUERIES",
 670                                             &max_parallel_bg_queries))
 671   {
 672     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 673                 "Number of allowed parallel background queries: %llu\n",
 674                 max_parallel_bg_queries);
 675   }
 676
 677   if (GNUNET_OK ==
 678       GNUNET_CONFIGURATION_get_value_time (c, "gns",
 679                                            "DEFAULT_LOOKUP_TIMEOUT",
 680                                            &default_lookup_timeout))
 681   {
 682     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 683                 "Default lookup timeout: %s\n",
 684                 GNUNET_STRINGS_relative_time_to_string (default_lookup_timeout,
 685                                                         GNUNET_YES));
 686   }
 687
 688   dht_handle = GNUNET_DHT_connect (c,
 689                                    (unsigned int) max_parallel_bg_queries);
 690   if (NULL == dht_handle)
 691   {
 692     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
 693                 _("Could not connect to DHT!\n"));
 694     GNUNET_SCHEDULER_add_now (&shutdown_task, NULL);
 695     return;
 696   }
 697
 698   if (GNUNET_OK ==
 699       GNUNET_CONFIGURATION_get_value_string (c, "gns", "DNS_ROOT",
 700                                              &dns_root_name))
 701   {
 702     if (GNUNET_OK !=
 703         GNUNET_CRYPTO_ecc_public_sign_key_from_string (dns_root_name,
 704                                                   strlen (dns_root_name),
 705                                                   &dns_root))
 706     {
 707       GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
 708                                  "gns", "DNS_ROOT",
 709                                  _("valid public key required"));
 710       GNUNET_SCHEDULER_add_now (&shutdown_task, NULL);
 711       GNUNET_free (dns_root_name);
 712       return;
 713     }
 714     GNUNET_log (GNUNET_ERROR_TYPE_INFO,
 715                 "DNS hijacking with root `%s' enabled. Connecting to DNS service.\n",
 716                 dns_root_name);
 717     GNUNET_free (dns_root_name);
 718     if (GNUNET_SYSERR ==
 719         GNS_interceptor_init (&dns_root, c))
 720     {
 721       GNUNET_SCHEDULER_add_now (&shutdown_task, NULL);
 722       return;
 723     }
 724   }
 725   GNS_resolver_init (namestore_handle, dht_handle,
 726                      c,
 727                      max_parallel_bg_queries);
 728   GNS_shorten_init (namestore_handle, dht_handle);
 729   GNUNET_SERVER_disconnect_notify (server,
 730                                    &notify_client_disconnect,
 731                                    NULL);
 732   /* Schedule periodic put for our records. */
 733   first_zone_iteration = GNUNET_YES;
 734   GNUNET_SERVER_add_handlers (server, handlers);
 735   statistics = GNUNET_STATISTICS_create ("gns", c);
 736   nc = GNUNET_SERVER_notification_context_create (server, 1);
 737   zone_publish_task = GNUNET_SCHEDULER_add_now (&publish_zone_dht_start,
 738                                                 NULL);
 739   GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL,
 740                                 &shutdown_task, NULL);
 741 }
 742
 743
 744 /**
 745  * The main function for the GNS service.
 746  *
 747  * @param argc number of arguments from the command line
 748  * @param argv command line arguments
 749  * @return 0 ok, 1 on error
 750  */
 751 int
 752 main (int argc, char *const *argv)
 753 {
 754   int ret;
 755
 756   ret =
 757       (GNUNET_OK ==
 758        GNUNET_SERVICE_run (argc, argv, "gns", GNUNET_SERVICE_OPTION_NONE, &run,
 759                            NULL)) ? 0 : 1;
 760   return ret;
 761 }
 762
 763 /* end of gnunet-service-gns.c */