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  * #GNUNET_YES if ipv6 is supported
 175  */
 176 static int v6_enabled;
 177
 178 /**
 179  * #GNUNET_YES if ipv4 is supported
 180  */
 181 static int v4_enabled;
 182
 183 /**
 184  * Handle to the statistics service
 185  */
 186 static struct GNUNET_STATISTICS_Handle *statistics;
 187
 188
 189 /**
 190  * Task run during shutdown.
 191  *
 192  * @param cls unused
 193  * @param tc unused
 194  */
 195 static void
 196 shutdown_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
 197 {
 198   struct ClientLookupHandle *clh;
 199
 200   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 201               "Shutting down!\n");
 202   GNUNET_SERVER_notification_context_destroy (nc);
 203   while (NULL != (clh = clh_head))
 204   {
 205     GNUNET_SERVER_client_set_user_context (clh->client, NULL);
 206     GNS_resolver_lookup_cancel (clh->lookup);
 207     GNUNET_CONTAINER_DLL_remove (clh_head, clh_tail, clh);
 208     GNUNET_free (clh);
 209   }
 210
 211   GNS_interceptor_done ();
 212   GNS_resolver_done ();
 213   GNS_shorten_done ();
 214   if (NULL != statistics)
 215   {
 216     GNUNET_STATISTICS_destroy (statistics, GNUNET_NO);
 217     statistics = NULL;
 218   }
 219   if (GNUNET_SCHEDULER_NO_TASK != zone_publish_task)
 220   {
 221     GNUNET_SCHEDULER_cancel (zone_publish_task);
 222     zone_publish_task = GNUNET_SCHEDULER_NO_TASK;
 223   }
 224   if (NULL != namestore_iter)
 225   {
 226     GNUNET_NAMESTORE_zone_iteration_stop (namestore_iter);
 227     namestore_iter = NULL;
 228   }
 229   if (NULL != namestore_handle)
 230   {
 231     GNUNET_NAMESTORE_disconnect (namestore_handle);
 232     namestore_handle = NULL;
 233   }
 234   if (NULL != active_put)
 235   {
 236     GNUNET_DHT_put_cancel (active_put);
 237     active_put = NULL;
 238   }
 239   if (NULL != dht_handle)
 240   {
 241     GNUNET_DHT_disconnect (dht_handle);
 242     dht_handle = NULL;
 243   }
 244 }
 245
 246
 247 /**
 248  * Method called periodically that triggers iteration over authoritative records
 249  *
 250  * @param cls closure
 251  * @param tc task context
 252  */
 253 static void
 254 publish_zone_dht_next (void *cls,
 255                        const struct GNUNET_SCHEDULER_TaskContext *tc)
 256 {
 257   zone_publish_task = GNUNET_SCHEDULER_NO_TASK;
 258   GNUNET_NAMESTORE_zone_iterator_next (namestore_iter);
 259 }
 260
 261
 262 /**
 263  * Periodically iterate over our zone and store everything in dht
 264  *
 265  * @param cls NULL
 266  * @param tc task context
 267  */
 268 static void
 269 publish_zone_dht_start (void *cls,
 270                         const struct GNUNET_SCHEDULER_TaskContext *tc);
 271
 272
 273 /**
 274  * Continuation called from DHT once the PUT operation is done.
 275  *
 276  * @param cls closure, NULL
 277  * @param success #GNUNET_OK on success
 278  */
 279 static void
 280 dht_put_continuation (void *cls,
 281                       int success)
 282 {
 283   struct GNUNET_TIME_Relative next_put_interval;
 284
 285   active_put = NULL;
 286   num_public_records++;
 287   if ( (num_public_records > last_num_public_records) &&
 288        (GNUNET_NO == first_zone_iteration) )
 289   {
 290     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 291                 "Last record count was lower than current record count.  Reducing interval.\n");
 292     put_interval = GNUNET_TIME_relative_divide (zone_publish_time_window,
 293                                                 num_public_records);
 294     next_put_interval = GNUNET_TIME_relative_divide (put_interval,
 295                                                      LATE_ITERATION_SPEEDUP_FACTOR);
 296   }
 297   else
 298     next_put_interval = put_interval;
 299
 300   GNUNET_STATISTICS_set (statistics,
 301                          "Current zone iteration interval (ms)",
 302                          next_put_interval.rel_value_us / 1000LL,
 303                          GNUNET_NO);
 304   zone_publish_task = GNUNET_SCHEDULER_add_delayed (next_put_interval,
 305                                                     &publish_zone_dht_next,
 306                                                     NULL);
 307 }
 308
 309
 310 /**
 311  * Function used to put all records successively into the DHT.
 312  *
 313  * @param cls the closure (NULL)
 314  * @param key the private key of the authority (ours)
 315  * @param name the name of the records, NULL once the iteration is done
 316  * @param rd_count the number of records in @a rd
 317  * @param rd the record data
 318  */
 319 static void
 320 put_gns_record (void *cls,
 321                 const struct GNUNET_CRYPTO_EcdsaPrivateKey *key,
 322                 const char *name,
 323                 unsigned int rd_count,
 324                 const struct GNUNET_NAMESTORE_RecordData *rd)
 325 {
 326   struct GNUNET_NAMESTORE_Block *block;
 327   struct GNUNET_HashCode query;
 328   struct GNUNET_TIME_Absolute expire;
 329   struct GNUNET_TIME_Absolute now;
 330   size_t block_size;
 331   struct GNUNET_NAMESTORE_RecordData rd_public[rd_count];
 332   unsigned int rd_public_count;
 333   unsigned int i;
 334
 335   if (NULL == name)
 336   {
 337     /* we're done with one iteration, calculate when to do the next one */
 338     namestore_iter = NULL;
 339     last_num_public_records = num_public_records;
 340     first_zone_iteration = GNUNET_NO;
 341     if (0 == num_public_records)
 342     {
 343       /**
 344        * If no records are known (startup) or none present
 345        * we can safely set the interval to the value for a single
 346        * record
 347        */
 348       put_interval = zone_publish_time_window;
 349       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG | GNUNET_ERROR_TYPE_BULK,
 350                   "No records in namestore database.\n");
 351     }
 352     else
 353     {
 354       put_interval = GNUNET_TIME_relative_divide (zone_publish_time_window,
 355                                                   num_public_records);
 356     }
 357     put_interval = GNUNET_TIME_relative_max (MINIMUM_ZONE_ITERATION_INTERVAL,
 358                                              put_interval);
 359
 360     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 361                 "Zone iteration finished. Adjusted zone iteration interval to %s\n",
 362                 GNUNET_STRINGS_relative_time_to_string (put_interval, GNUNET_YES));
 363     GNUNET_STATISTICS_set (statistics,
 364                            "Current zone iteration interval (in ms)",
 365                            put_interval.rel_value_us / 1000LL,
 366                            GNUNET_NO);
 367     GNUNET_STATISTICS_update (statistics,
 368                               "Number of zone iterations",
 369                               1,
 370                               GNUNET_NO);
 371     GNUNET_STATISTICS_set (statistics,
 372                            "Number of public records in DHT",
 373                            last_num_public_records,
 374                            GNUNET_NO);
 375     if (0 == num_public_records)
 376       zone_publish_task = GNUNET_SCHEDULER_add_delayed (put_interval,
 377                                                         &publish_zone_dht_start,
 378                                                         NULL);
 379     else
 380       zone_publish_task = GNUNET_SCHEDULER_add_now (&publish_zone_dht_start,
 381                                                     NULL);
 382     return;
 383   }
 384
 385   /* filter out records that are not public, and convert to
 386      absolute expiration time. */
 387   rd_public_count = 0;
 388   now = GNUNET_TIME_absolute_get ();
 389   for (i=0;i<rd_count;i++)
 390     if (0 == (rd[i].flags & (GNUNET_NAMESTORE_RF_PRIVATE |
 391                              GNUNET_NAMESTORE_RF_PENDING)))
 392     {
 393       rd_public[rd_public_count] = rd[i];
 394       if (0 != (rd[i].flags & GNUNET_NAMESTORE_RF_RELATIVE_EXPIRATION))
 395       {
 396         rd_public[rd_public_count].flags &= ~GNUNET_NAMESTORE_RF_RELATIVE_EXPIRATION;
 397         rd_public[rd_public_count].expiration_time += now.abs_value_us;
 398       }
 399       rd_public_count++;
 400     }
 401
 402   /* We got a set of records to publish */
 403   if (0 == rd_public_count)
 404   {
 405     zone_publish_task = GNUNET_SCHEDULER_add_now (&publish_zone_dht_next,
 406                                                    NULL);
 407     return;
 408   }
 409   expire = GNUNET_NAMESTORE_record_get_expiration_time (rd_public_count,
 410                                                         rd_public);
 411   block = GNUNET_NAMESTORE_block_create (key,
 412                                          expire,
 413                                          name,
 414                                          rd_public,
 415                                          rd_public_count);
 416   block_size = ntohl (block->purpose.size)
 417     + sizeof (struct GNUNET_CRYPTO_EcdsaSignature)
 418     + sizeof (struct GNUNET_CRYPTO_EcdsaPublicKey);
 419   GNUNET_NAMESTORE_query_from_private_key (key,
 420                                            name,
 421                                            &query);
 422
 423   active_put = GNUNET_DHT_put (dht_handle, &query,
 424                                DHT_GNS_REPLICATION_LEVEL,
 425                                GNUNET_DHT_RO_DEMULTIPLEX_EVERYWHERE,
 426                                GNUNET_BLOCK_TYPE_GNS_NAMERECORD,
 427                                block_size,
 428                                block,
 429                                expire,
 430                                DHT_OPERATION_TIMEOUT,
 431                                &dht_put_continuation,
 432                                NULL);
 433   if (NULL == active_put)
 434   {
 435     GNUNET_break (0);
 436     dht_put_continuation (NULL, GNUNET_NO);
 437   }
 438   GNUNET_free (block);
 439 }
 440
 441
 442 /**
 443  * Periodically iterate over our zone and store everything in dht
 444  *
 445  * @param cls NULL
 446  * @param tc task context
 447  */
 448 static void
 449 publish_zone_dht_start (void *cls,
 450                         const struct GNUNET_SCHEDULER_TaskContext *tc)
 451 {
 452   zone_publish_task = GNUNET_SCHEDULER_NO_TASK;
 453
 454   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 455               "Scheduling DHT zone update!\n");
 456   /* start counting again */
 457   num_public_records = 0;
 458   namestore_iter = GNUNET_NAMESTORE_zone_iteration_start (namestore_handle,
 459                                                           NULL, /* All zones */
 460                                                           &put_gns_record,
 461                                                           NULL);
 462 }
 463
 464
 465 /* END DHT ZONE PROPAGATION */
 466
 467
 468 /**
 469  * Reply to client with the result from our lookup.
 470  *
 471  * @param cls the closure (our client lookup handle)
 472  * @param rd_count the number of records in @a rd
 473  * @param rd the record data
 474  */
 475 static void
 476 send_lookup_response (void* cls,
 477                       uint32_t rd_count,
 478                       const struct GNUNET_NAMESTORE_RecordData *rd)
 479 {
 480   struct ClientLookupHandle *clh = cls;
 481   struct GNUNET_GNS_ClientLookupResultMessage *rmsg;
 482   size_t len;
 483
 484   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 485               "Sending `%s' message with %d results\n",
 486               "LOOKUP_RESULT",
 487               rd_count);
 488
 489   len = GNUNET_NAMESTORE_records_get_size (rd_count, rd);
 490   rmsg = GNUNET_malloc (len + sizeof (struct GNUNET_GNS_ClientLookupResultMessage));
 491   rmsg->header.type = htons (GNUNET_MESSAGE_TYPE_GNS_LOOKUP_RESULT);
 492   rmsg->header.size = htons (len + sizeof(struct GNUNET_GNS_ClientLookupResultMessage));
 493   rmsg->id = clh->request_id;
 494   rmsg->rd_count = htonl (rd_count);
 495   GNUNET_NAMESTORE_records_serialize (rd_count, rd, len,
 496                                       (char*) &rmsg[1]);
 497   GNUNET_SERVER_notification_context_unicast (nc,
 498                                               clh->client,
 499                                               &rmsg->header,
 500                                               GNUNET_NO);
 501   GNUNET_free (rmsg);
 502   GNUNET_CONTAINER_DLL_remove (clh_head, clh_tail, clh);
 503   GNUNET_SERVER_client_set_user_context (clh->client, NULL);
 504   GNUNET_free (clh);
 505   GNUNET_STATISTICS_update (statistics,
 506                             "Completed lookups", 1,
 507                             GNUNET_NO);
 508   GNUNET_STATISTICS_update (statistics,
 509                             "Records resolved",
 510                             rd_count,
 511                             GNUNET_NO);
 512 }
 513
 514
 515 /**
 516  * Handle lookup requests from client
 517  *
 518  * @param cls the closure
 519  * @param client the client
 520  * @param message the message
 521  */
 522 static void
 523 handle_lookup (void *cls,
 524                struct GNUNET_SERVER_Client *client,
 525                const struct GNUNET_MessageHeader *message)
 526 {
 527   char name[GNUNET_DNSPARSER_MAX_NAME_LENGTH + 1];
 528   struct ClientLookupHandle *clh;
 529   char *nameptr = name;
 530   const char *utf_in;
 531   const struct GNUNET_CRYPTO_EcdsaPrivateKey *key;
 532   uint16_t msg_size;
 533   const struct GNUNET_GNS_ClientLookupMessage *sh_msg;
 534
 535   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 536               "Received `%s' message\n",
 537               "LOOKUP");
 538   msg_size = ntohs (message->size);
 539   if (msg_size < sizeof (struct GNUNET_GNS_ClientLookupMessage))
 540   {
 541     GNUNET_break (0);
 542     GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
 543     return;
 544   }
 545   sh_msg = (const struct GNUNET_GNS_ClientLookupMessage *) message;
 546   GNUNET_SERVER_notification_context_add (nc, client);
 547   if (GNUNET_YES == ntohs (sh_msg->have_key))
 548     key = &sh_msg->shorten_key;
 549   else
 550     key = NULL;
 551   utf_in = (const char *) &sh_msg[1];
 552   if ( ('\0' != utf_in[msg_size - sizeof (struct GNUNET_GNS_ClientLookupMessage) - 1]) ||
 553        (strlen (utf_in) > GNUNET_DNSPARSER_MAX_NAME_LENGTH) )
 554   {
 555     GNUNET_break (0);
 556     GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
 557     return;
 558   }
 559   GNUNET_STRINGS_utf8_tolower (utf_in, &nameptr);
 560   GNUNET_SERVER_receive_done (client, GNUNET_OK);
 561
 562   clh = GNUNET_new (struct ClientLookupHandle);
 563   GNUNET_SERVER_client_set_user_context (client, clh);
 564   GNUNET_CONTAINER_DLL_insert (clh_head, clh_tail, clh);
 565   clh->client = client;
 566   clh->request_id = sh_msg->id;
 567   if ( (GNUNET_DNSPARSER_TYPE_A == ntohl (sh_msg->type)) &&
 568        (GNUNET_OK != v4_enabled) )
 569   {
 570     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 571                 "LOOKUP: Query for A record but AF_INET not supported!");
 572     send_lookup_response (clh, 0, NULL);
 573     return;
 574   }
 575   if ( (GNUNET_DNSPARSER_TYPE_AAAA == ntohl (sh_msg->type)) &&
 576        (GNUNET_OK != v6_enabled) )
 577   {
 578     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 579                 "LOOKUP: Query for AAAA record but AF_INET6 not supported!");
 580     send_lookup_response (clh, 0, NULL);
 581     return;
 582   }
 583   clh->lookup = GNS_resolver_lookup (&sh_msg->zone,
 584                                      ntohl (sh_msg->type),
 585                                      name,
 586                                      key,
 587                                      ntohl (sh_msg->only_cached),
 588                                      &send_lookup_response, clh);
 589   GNUNET_STATISTICS_update (statistics,
 590                             "Lookup attempts",
 591                             1, GNUNET_NO);
 592 }
 593
 594
 595 /**
 596  * One of our clients disconnected, clean up after it.
 597  *
 598  * @param cls NULL
 599  * @param client the client that disconnected
 600  */
 601 static void
 602 notify_client_disconnect (void *cls,
 603                           struct GNUNET_SERVER_Client *client)
 604 {
 605   struct ClientLookupHandle *clh;
 606
 607   if (NULL == client)
 608     return;
 609   clh = GNUNET_SERVER_client_get_user_context (client, struct ClientLookupHandle);
 610   if (NULL == clh)
 611     return;
 612   GNS_resolver_lookup_cancel (clh->lookup);
 613   GNUNET_CONTAINER_DLL_remove (clh_head, clh_tail, clh);
 614   GNUNET_free (clh);
 615 }
 616
 617
 618 /**
 619  * Process GNS requests.
 620  *
 621  * @param cls closure
 622  * @param server the initialized server
 623  * @param c configuration to use
 624  */
 625 static void
 626 run (void *cls, struct GNUNET_SERVER_Handle *server,
 627      const struct GNUNET_CONFIGURATION_Handle *c)
 628 {
 629   static const struct GNUNET_SERVER_MessageHandler handlers[] = {
 630     { &handle_lookup, NULL, GNUNET_MESSAGE_TYPE_GNS_LOOKUP, 0},
 631     {NULL, NULL, 0, 0}
 632   };
 633   struct GNUNET_CRYPTO_EcdsaPublicKey dns_root;
 634   unsigned long long max_parallel_bg_queries = 0;
 635   char *dns_root_name;
 636
 637   v6_enabled = GNUNET_NETWORK_test_pf (PF_INET6);
 638   v4_enabled = GNUNET_NETWORK_test_pf (PF_INET);
 639
 640   namestore_handle = GNUNET_NAMESTORE_connect (c);
 641   if (NULL == namestore_handle)
 642   {
 643     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
 644                 _("Failed to connect to the namestore!\n"));
 645     GNUNET_SCHEDULER_shutdown ();
 646     return;
 647   }
 648
 649   put_interval = INITIAL_PUT_INTERVAL;
 650   zone_publish_time_window = DEFAULT_ZONE_PUBLISH_TIME_WINDOW;
 651
 652   if (GNUNET_OK ==
 653       GNUNET_CONFIGURATION_get_value_time (c, "gns",
 654                                            "ZONE_PUBLISH_TIME_WINDOW",
 655                                            &zone_publish_time_window))
 656   {
 657     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 658                 "Time window for zone iteration: %s\n",
 659                 GNUNET_STRINGS_relative_time_to_string (zone_publish_time_window, GNUNET_YES));
 660   }
 661   if (GNUNET_OK ==
 662       GNUNET_CONFIGURATION_get_value_number (c, "gns",
 663                                             "MAX_PARALLEL_BACKGROUND_QUERIES",
 664                                             &max_parallel_bg_queries))
 665   {
 666     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 667                 "Number of allowed parallel background queries: %llu\n",
 668                 max_parallel_bg_queries);
 669   }
 670
 671   dht_handle = GNUNET_DHT_connect (c,
 672                                    (unsigned int) max_parallel_bg_queries);
 673   if (NULL == dht_handle)
 674   {
 675     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
 676                 _("Could not connect to DHT!\n"));
 677     GNUNET_SCHEDULER_add_now (&shutdown_task, NULL);
 678     return;
 679   }
 680
 681   if (GNUNET_OK ==
 682       GNUNET_CONFIGURATION_get_value_string (c, "gns", "DNS_ROOT",
 683                                              &dns_root_name))
 684   {
 685     if (GNUNET_OK !=
 686         GNUNET_CRYPTO_ecdsa_public_key_from_string (dns_root_name,
 687                                                   strlen (dns_root_name),
 688                                                   &dns_root))
 689     {
 690       GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
 691                                  "gns", "DNS_ROOT",
 692                                  _("valid public key required"));
 693       GNUNET_SCHEDULER_add_now (&shutdown_task, NULL);
 694       GNUNET_free (dns_root_name);
 695       return;
 696     }
 697     GNUNET_log (GNUNET_ERROR_TYPE_INFO,
 698                 "DNS hijacking with root `%s' enabled. Connecting to DNS service.\n",
 699                 dns_root_name);
 700     GNUNET_free (dns_root_name);
 701     if (GNUNET_SYSERR ==
 702         GNS_interceptor_init (&dns_root, c))
 703     {
 704       GNUNET_SCHEDULER_add_now (&shutdown_task, NULL);
 705       return;
 706     }
 707   }
 708   GNS_resolver_init (namestore_handle, dht_handle,
 709                      c,
 710                      max_parallel_bg_queries);
 711   GNS_shorten_init (namestore_handle, dht_handle);
 712   GNUNET_SERVER_disconnect_notify (server,
 713                                    &notify_client_disconnect,
 714                                    NULL);
 715   /* Schedule periodic put for our records. */
 716   first_zone_iteration = GNUNET_YES;
 717   GNUNET_SERVER_add_handlers (server, handlers);
 718   statistics = GNUNET_STATISTICS_create ("gns", c);
 719   nc = GNUNET_SERVER_notification_context_create (server, 1);
 720   zone_publish_task = GNUNET_SCHEDULER_add_now (&publish_zone_dht_start,
 721                                                 NULL);
 722   GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL,
 723                                 &shutdown_task, NULL);
 724 }
 725
 726
 727 /**
 728  * The main function for the GNS service.
 729  *
 730  * @param argc number of arguments from the command line
 731  * @param argv command line arguments
 732  * @return 0 ok, 1 on error
 733  */
 734 int
 735 main (int argc, char *const *argv)
 736 {
 737   int ret;
 738
 739   ret =
 740       (GNUNET_OK ==
 741        GNUNET_SERVICE_run (argc, argv, "gns", GNUNET_SERVICE_OPTION_NONE, &run,
 742                            NULL)) ? 0 : 1;
 743   return ret;
 744 }
 745
 746 /* end of gnunet-service-gns.c */