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     GNS_resolver_lookup_cancel (clh->lookup);
 211     GNUNET_CONTAINER_DLL_remove (clh_head, clh_tail, clh);
 212     GNUNET_free (clh);
 213   }
 214
 215   GNS_interceptor_done ();
 216   GNS_resolver_done ();
 217   GNS_shorten_done ();
 218   if (NULL != statistics)
 219   {
 220     GNUNET_STATISTICS_destroy (statistics, GNUNET_NO);
 221     statistics = NULL;
 222   }
 223   if (GNUNET_SCHEDULER_NO_TASK != zone_publish_task)
 224   {
 225     GNUNET_SCHEDULER_cancel (zone_publish_task);
 226     zone_publish_task = GNUNET_SCHEDULER_NO_TASK;
 227   }
 228   if (NULL != namestore_iter)
 229   {
 230     GNUNET_NAMESTORE_zone_iteration_stop (namestore_iter);
 231     namestore_iter = NULL;
 232   }
 233   if (NULL != namestore_handle)
 234   {
 235     GNUNET_NAMESTORE_disconnect (namestore_handle);
 236     namestore_handle = NULL;
 237   }
 238   if (NULL != active_put)
 239   {
 240     GNUNET_DHT_put_cancel (active_put);
 241     active_put = NULL;
 242   }
 243   if (NULL != dht_handle)
 244   {
 245     GNUNET_DHT_disconnect (dht_handle);
 246     dht_handle = NULL;
 247   }
 248 }
 249
 250
 251 /**
 252  * Method called periodically that triggers iteration over authoritative records
 253  *
 254  * @param cls closure
 255  * @param tc task context
 256  */
 257 static void
 258 publish_zone_dht_next (void *cls,
 259                        const struct GNUNET_SCHEDULER_TaskContext *tc)
 260 {
 261   zone_publish_task = GNUNET_SCHEDULER_NO_TASK;
 262   GNUNET_NAMESTORE_zone_iterator_next (namestore_iter);
 263 }
 264
 265
 266 /**
 267  * Periodically iterate over our zone and store everything in dht
 268  *
 269  * @param cls NULL
 270  * @param tc task context
 271  */
 272 static void
 273 publish_zone_dht_start (void *cls,
 274                         const struct GNUNET_SCHEDULER_TaskContext *tc);
 275
 276
 277 /**
 278  * Continuation called from DHT once the PUT operation is done.
 279  *
 280  * @param cls closure, NULL
 281  * @param success #GNUNET_OK on success
 282  */
 283 static void
 284 dht_put_continuation (void *cls,
 285                       int success)
 286 {
 287   struct GNUNET_TIME_Relative next_put_interval;
 288
 289   active_put = NULL;
 290   num_public_records++;
 291   if ( (num_public_records > last_num_public_records) &&
 292        (GNUNET_NO == first_zone_iteration) )
 293   {
 294     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 295                 "Last record count was lower than current record count.  Reducing interval.\n");
 296     put_interval = GNUNET_TIME_relative_divide (zone_publish_time_window,
 297                                                 num_public_records);
 298     next_put_interval = GNUNET_TIME_relative_divide (put_interval,
 299                                                      LATE_ITERATION_SPEEDUP_FACTOR);
 300   }
 301   else
 302     next_put_interval = put_interval;
 303
 304   GNUNET_STATISTICS_set (statistics,
 305                          "Current zone iteration interval (ms)",
 306                          next_put_interval.rel_value_us / 1000LL,
 307                          GNUNET_NO);
 308   zone_publish_task = GNUNET_SCHEDULER_add_delayed (next_put_interval,
 309                                                     &publish_zone_dht_next,
 310                                                     NULL);
 311 }
 312
 313
 314 /**
 315  * Function used to put all records successively into the DHT.
 316  *
 317  * @param cls the closure (NULL)
 318  * @param key the private key of the authority (ours)
 319  * @param name the name of the records, NULL once the iteration is done
 320  * @param rd_count the number of records in @a rd
 321  * @param rd the record data
 322  */
 323 static void
 324 put_gns_record (void *cls,
 325                 const struct GNUNET_CRYPTO_EccPrivateKey *key,
 326                 const char *name,
 327                 unsigned int rd_count,
 328                 const struct GNUNET_NAMESTORE_RecordData *rd)
 329 {
 330   struct GNUNET_NAMESTORE_Block *block;
 331   struct GNUNET_HashCode query;
 332   struct GNUNET_TIME_Absolute expire;
 333   struct GNUNET_TIME_Absolute now;
 334   size_t block_size;
 335   struct GNUNET_NAMESTORE_RecordData rd_public[rd_count];
 336   unsigned int rd_public_count;
 337   unsigned int i;
 338
 339   if (NULL == name)
 340   {
 341     /* we're done with one iteration, calculate when to do the next one */
 342     namestore_iter = NULL;
 343     last_num_public_records = num_public_records;
 344     first_zone_iteration = GNUNET_NO;
 345     if (0 == num_public_records)
 346     {
 347       /**
 348        * If no records are known (startup) or none present
 349        * we can safely set the interval to the value for a single
 350        * record
 351        */
 352       put_interval = zone_publish_time_window;
 353       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG | GNUNET_ERROR_TYPE_BULK,
 354                   "No records in namestore database.\n");
 355     }
 356     else
 357     {
 358       put_interval = GNUNET_TIME_relative_divide (zone_publish_time_window,
 359                                                   num_public_records);
 360     }
 361     put_interval = GNUNET_TIME_relative_max (MINIMUM_ZONE_ITERATION_INTERVAL,
 362                                              put_interval);
 363
 364     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 365                 "Zone iteration finished. Adjusted zone iteration interval to %s\n",
 366                 GNUNET_STRINGS_relative_time_to_string (put_interval, GNUNET_YES));
 367     GNUNET_STATISTICS_set (statistics,
 368                            "Current zone iteration interval (in ms)",
 369                            put_interval.rel_value_us / 1000LL,
 370                            GNUNET_NO);
 371     GNUNET_STATISTICS_update (statistics,
 372                               "Number of zone iterations",
 373                               1,
 374                               GNUNET_NO);
 375     GNUNET_STATISTICS_set (statistics,
 376                            "Number of public records in DHT",
 377                            last_num_public_records,
 378                            GNUNET_NO);
 379     if (0 == num_public_records)
 380       zone_publish_task = GNUNET_SCHEDULER_add_delayed (put_interval,
 381                                                         &publish_zone_dht_start,
 382                                                         NULL);
 383     else
 384       zone_publish_task = GNUNET_SCHEDULER_add_now (&publish_zone_dht_start,
 385                                                     NULL);
 386     return;
 387   }
 388
 389   /* filter out records that are not public, and convert to
 390      absolute expiration time. */
 391   rd_public_count = 0;
 392   now = GNUNET_TIME_absolute_get ();
 393   for (i=0;i<rd_count;i++)
 394     if (0 == (rd[i].flags & (GNUNET_NAMESTORE_RF_PRIVATE |
 395                              GNUNET_NAMESTORE_RF_PENDING)))
 396     {
 397       rd_public[rd_public_count] = rd[i];
 398       if (0 != (rd[i].flags & GNUNET_NAMESTORE_RF_RELATIVE_EXPIRATION))
 399       {
 400         rd_public[rd_public_count].flags &= ~GNUNET_NAMESTORE_RF_RELATIVE_EXPIRATION;
 401         rd_public[rd_public_count].expiration_time += now.abs_value_us;
 402       }
 403       rd_public_count++;
 404     }
 405
 406   /* We got a set of records to publish */
 407   if (0 == rd_public_count)
 408   {
 409     zone_publish_task = GNUNET_SCHEDULER_add_now (&publish_zone_dht_next,
 410                                                    NULL);
 411     return;
 412   }
 413   expire = GNUNET_NAMESTORE_record_get_expiration_time (rd_public_count,
 414                                                         rd_public);
 415   block = GNUNET_NAMESTORE_block_create (key,
 416                                          expire,
 417                                          name,
 418                                          rd_public,
 419                                          rd_public_count);
 420   block_size = ntohl (block->purpose.size)
 421     + sizeof (struct GNUNET_CRYPTO_EccSignature)
 422     + sizeof (struct GNUNET_CRYPTO_EccPublicKey);
 423   GNUNET_NAMESTORE_query_from_private_key (key,
 424                                            name,
 425                                            &query);
 426
 427   active_put = GNUNET_DHT_put (dht_handle, &query,
 428                                DHT_GNS_REPLICATION_LEVEL,
 429                                GNUNET_DHT_RO_DEMULTIPLEX_EVERYWHERE,
 430                                GNUNET_BLOCK_TYPE_GNS_NAMERECORD,
 431                                block_size,
 432                                block,
 433                                expire,
 434                                DHT_OPERATION_TIMEOUT,
 435                                &dht_put_continuation,
 436                                NULL);
 437   if (NULL == active_put)
 438   {
 439     GNUNET_break (0);
 440     dht_put_continuation (NULL, GNUNET_NO);
 441   }
 442   GNUNET_free (block);
 443 }
 444
 445
 446 /**
 447  * Periodically iterate over our zone and store everything in dht
 448  *
 449  * @param cls NULL
 450  * @param tc task context
 451  */
 452 static void
 453 publish_zone_dht_start (void *cls,
 454                         const struct GNUNET_SCHEDULER_TaskContext *tc)
 455 {
 456   zone_publish_task = GNUNET_SCHEDULER_NO_TASK;
 457
 458   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 459               "Scheduling DHT zone update!\n");
 460   /* start counting again */
 461   num_public_records = 0;
 462   namestore_iter = GNUNET_NAMESTORE_zone_iteration_start (namestore_handle,
 463                                                           NULL, /* All zones */
 464                                                           &put_gns_record,
 465                                                           NULL);
 466 }
 467
 468
 469 /* END DHT ZONE PROPAGATION */
 470
 471
 472 /**
 473  * Reply to client with the result from our lookup.
 474  *
 475  * @param cls the closure (our client lookup handle)
 476  * @param rd_count the number of records in @a rd
 477  * @param rd the record data
 478  */
 479 static void
 480 send_lookup_response (void* cls,
 481                       uint32_t rd_count,
 482                       const struct GNUNET_NAMESTORE_RecordData *rd)
 483 {
 484   struct ClientLookupHandle *clh = cls;
 485   struct GNUNET_GNS_ClientLookupResultMessage *rmsg;
 486   size_t len;
 487
 488   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 489               "Sending `%s' message with %d results\n",
 490               "LOOKUP_RESULT",
 491               rd_count);
 492
 493   len = GNUNET_NAMESTORE_records_get_size (rd_count, rd);
 494   rmsg = GNUNET_malloc (len + sizeof (struct GNUNET_GNS_ClientLookupResultMessage));
 495   rmsg->header.type = htons (GNUNET_MESSAGE_TYPE_GNS_LOOKUP_RESULT);
 496   rmsg->header.size = htons (len + sizeof(struct GNUNET_GNS_ClientLookupResultMessage));
 497   rmsg->id = clh->request_id;
 498   rmsg->rd_count = htonl (rd_count);
 499   GNUNET_NAMESTORE_records_serialize (rd_count, rd, len,
 500                                       (char*) &rmsg[1]);
 501   GNUNET_SERVER_notification_context_unicast (nc,
 502                                               clh->client,
 503                                               &rmsg->header,
 504                                               GNUNET_NO);
 505   GNUNET_free (rmsg);
 506   GNUNET_SERVER_receive_done (clh->client,
 507                               GNUNET_OK);
 508   GNUNET_CONTAINER_DLL_remove (clh_head, clh_tail, clh);
 509   GNUNET_SERVER_client_set_user_context (clh->client, NULL);
 510   GNUNET_free (clh);
 511   GNUNET_STATISTICS_update (statistics,
 512                             "Completed lookups", 1,
 513                             GNUNET_NO);
 514   GNUNET_STATISTICS_update (statistics,
 515                             "Records resolved",
 516                             rd_count,
 517                             GNUNET_NO);
 518 }
 519
 520
 521 /**
 522  * Handle lookup requests from client
 523  *
 524  * @param cls the closure
 525  * @param client the client
 526  * @param message the message
 527  */
 528 static void
 529 handle_lookup (void *cls,
 530                struct GNUNET_SERVER_Client *client,
 531                const struct GNUNET_MessageHeader *message)
 532 {
 533   char name[GNUNET_DNSPARSER_MAX_NAME_LENGTH + 1];
 534   struct ClientLookupHandle *clh;
 535   char *nameptr = name;
 536   const char *utf_in;
 537   const struct GNUNET_CRYPTO_EccPrivateKey *key;
 538   uint16_t msg_size;
 539   const struct GNUNET_GNS_ClientLookupMessage *sh_msg;
 540
 541   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 542               "Received `%s' message\n",
 543               "LOOKUP");
 544   msg_size = ntohs (message->size);
 545   if (msg_size < sizeof (struct GNUNET_GNS_ClientLookupMessage))
 546   {
 547     GNUNET_break (0);
 548     GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
 549     return;
 550   }
 551   sh_msg = (const struct GNUNET_GNS_ClientLookupMessage *) message;
 552   GNUNET_SERVER_notification_context_add (nc, client);
 553   if (GNUNET_YES == ntohl (sh_msg->have_key))
 554     key = &sh_msg->shorten_key;
 555   else
 556     key = NULL;
 557   utf_in = (const char *) &sh_msg[1];
 558   if ( ('\0' != utf_in[msg_size - sizeof (struct GNUNET_GNS_ClientLookupMessage) - 1]) ||
 559        (strlen (utf_in) > GNUNET_DNSPARSER_MAX_NAME_LENGTH) )
 560   {
 561     GNUNET_break (0);
 562     GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
 563     return;
 564   }
 565   GNUNET_STRINGS_utf8_tolower (utf_in, &nameptr);
 566
 567   clh = GNUNET_new (struct ClientLookupHandle);
 568   GNUNET_SERVER_client_set_user_context (client, clh);
 569   GNUNET_CONTAINER_DLL_insert (clh_head, clh_tail, clh);
 570   clh->client = client;
 571   clh->request_id = sh_msg->id;
 572   if ( (GNUNET_DNSPARSER_TYPE_A == ntohl (sh_msg->type)) &&
 573        (GNUNET_OK != v4_enabled) )
 574   {
 575     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 576                 "LOOKUP: Query for A record but AF_INET not supported!");
 577     send_lookup_response (clh, 0, NULL);
 578     return;
 579   }
 580   if ( (GNUNET_DNSPARSER_TYPE_AAAA == ntohl (sh_msg->type)) &&
 581        (GNUNET_OK != v6_enabled) )
 582   {
 583     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 584                 "LOOKUP: Query for AAAA record but AF_INET6 not supported!");
 585     send_lookup_response (clh, 0, NULL);
 586     return;
 587   }
 588   clh->lookup = GNS_resolver_lookup (&sh_msg->zone,
 589                                      ntohl (sh_msg->type),
 590                                      name,
 591                                      key,
 592                                      ntohl (sh_msg->only_cached),
 593                                      &send_lookup_response, clh);
 594   GNUNET_STATISTICS_update (statistics,
 595                             "Lookup attempts",
 596                             1, GNUNET_NO);
 597 }
 598
 599
 600 /**
 601  * One of our clients disconnected, clean up after it.
 602  *
 603  * @param cls NULL
 604  * @param client the client that disconnected
 605  */
 606 static void
 607 notify_client_disconnect (void *cls,
 608                           struct GNUNET_SERVER_Client *client)
 609 {
 610   struct ClientLookupHandle *clh;
 611
 612   if (NULL == client)
 613     return;
 614   clh = GNUNET_SERVER_client_get_user_context (client, struct ClientLookupHandle);
 615   if (NULL == clh)
 616     return;
 617   GNS_resolver_lookup_cancel (clh->lookup);
 618   GNUNET_CONTAINER_DLL_remove (clh_head, clh_tail, clh);
 619   GNUNET_free (clh);
 620 }
 621
 622
 623 /**
 624  * Process GNS requests.
 625  *
 626  * @param cls closure
 627  * @param server the initialized server
 628  * @param c configuration to use
 629  */
 630 static void
 631 run (void *cls, struct GNUNET_SERVER_Handle *server,
 632      const struct GNUNET_CONFIGURATION_Handle *c)
 633 {
 634   static const struct GNUNET_SERVER_MessageHandler handlers[] = {
 635     { &handle_lookup, NULL, GNUNET_MESSAGE_TYPE_GNS_LOOKUP, 0},
 636     {NULL, NULL, 0, 0}
 637   };
 638   struct GNUNET_CRYPTO_EccPublicKey dns_root;
 639   unsigned long long max_parallel_bg_queries = 0;
 640   char *dns_root_name;
 641
 642   v6_enabled = GNUNET_NETWORK_test_pf (PF_INET6);
 643   v4_enabled = GNUNET_NETWORK_test_pf (PF_INET);
 644
 645   namestore_handle = GNUNET_NAMESTORE_connect (c);
 646   if (NULL == namestore_handle)
 647   {
 648     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
 649                 _("Failed to connect to the namestore!\n"));
 650     GNUNET_SCHEDULER_shutdown ();
 651     return;
 652   }
 653
 654   put_interval = INITIAL_PUT_INTERVAL;
 655   zone_publish_time_window = DEFAULT_ZONE_PUBLISH_TIME_WINDOW;
 656
 657   if (GNUNET_OK ==
 658       GNUNET_CONFIGURATION_get_value_time (c, "gns",
 659                                            "ZONE_PUBLISH_TIME_WINDOW",
 660                                            &zone_publish_time_window))
 661   {
 662     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 663                 "Time window for zone iteration: %s\n",
 664                 GNUNET_STRINGS_relative_time_to_string (zone_publish_time_window, GNUNET_YES));
 665   }
 666   if (GNUNET_OK ==
 667       GNUNET_CONFIGURATION_get_value_number (c, "gns",
 668                                             "MAX_PARALLEL_BACKGROUND_QUERIES",
 669                                             &max_parallel_bg_queries))
 670   {
 671     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 672                 "Number of allowed parallel background queries: %llu\n",
 673                 max_parallel_bg_queries);
 674   }
 675
 676   if (GNUNET_OK ==
 677       GNUNET_CONFIGURATION_get_value_time (c, "gns",
 678                                            "DEFAULT_LOOKUP_TIMEOUT",
 679                                            &default_lookup_timeout))
 680   {
 681     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 682                 "Default lookup timeout: %s\n",
 683                 GNUNET_STRINGS_relative_time_to_string (default_lookup_timeout,
 684                                                         GNUNET_YES));
 685   }
 686
 687   dht_handle = GNUNET_DHT_connect (c,
 688                                    (unsigned int) max_parallel_bg_queries);
 689   if (NULL == dht_handle)
 690   {
 691     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
 692                 _("Could not connect to DHT!\n"));
 693     GNUNET_SCHEDULER_add_now (&shutdown_task, NULL);
 694     return;
 695   }
 696
 697   if (GNUNET_OK ==
 698       GNUNET_CONFIGURATION_get_value_string (c, "gns", "DNS_ROOT",
 699                                              &dns_root_name))
 700   {
 701     if (GNUNET_OK !=
 702         GNUNET_CRYPTO_ecc_public_key_from_string (dns_root_name,
 703                                                   strlen (dns_root_name),
 704                                                   &dns_root))
 705     {
 706       GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
 707                                  "gns", "DNS_ROOT",
 708                                  _("valid public key required"));
 709       GNUNET_SCHEDULER_add_now (&shutdown_task, NULL);
 710       GNUNET_free (dns_root_name);
 711       return;
 712     }
 713     GNUNET_log (GNUNET_ERROR_TYPE_INFO,
 714                 "DNS hijacking with root `%s' enabled. Connecting to DNS service.\n",
 715                 dns_root_name);
 716     GNUNET_free (dns_root_name);
 717     if (GNUNET_SYSERR ==
 718         GNS_interceptor_init (&dns_root, c))
 719     {
 720       GNUNET_SCHEDULER_add_now (&shutdown_task, NULL);
 721       return;
 722     }
 723   }
 724   GNS_resolver_init (namestore_handle, dht_handle,
 725                      c,
 726                      max_parallel_bg_queries);
 727   GNS_shorten_init (namestore_handle, dht_handle);
 728   GNUNET_SERVER_disconnect_notify (server,
 729                                    &notify_client_disconnect,
 730                                    NULL);
 731   /* Schedule periodic put for our records. */
 732   first_zone_iteration = GNUNET_YES;
 733   GNUNET_SERVER_add_handlers (server, handlers);
 734   statistics = GNUNET_STATISTICS_create ("gns", c);
 735   nc = GNUNET_SERVER_notification_context_create (server, 1);
 736   zone_publish_task = GNUNET_SCHEDULER_add_now (&publish_zone_dht_start,
 737                                                 NULL);
 738   GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL,
 739                                 &shutdown_task, NULL);
 740 }
 741
 742
 743 /**
 744  * The main function for the GNS service.
 745  *
 746  * @param argc number of arguments from the command line
 747  * @param argv command line arguments
 748  * @return 0 ok, 1 on error
 749  */
 750 int
 751 main (int argc, char *const *argv)
 752 {
 753   int ret;
 754
 755   ret =
 756       (GNUNET_OK ==
 757        GNUNET_SERVICE_run (argc, argv, "gns", GNUNET_SERVICE_OPTION_NONE, &run,
 758                            NULL)) ? 0 : 1;
 759   return ret;
 760 }
 761
 762 /* end of gnunet-service-gns.c */