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 GNUnet GNS service
  23  * @author Martin Schanzenbach
  24  * @author Christian Grothoff
  25  */
  26 #include "platform.h"
  27 #include "gnunet_util_lib.h"
  28 #include "gnunet_transport_service.h"
  29 #include "gnunet_dns_service.h"
  30 #include "gnunet_dnsparser_lib.h"
  31 #include "gnunet_dht_service.h"
  32 #include "gnunet_namestore_service.h"
  33 #include "gnunet_gns_service.h"
  34 #include "gnunet_statistics_service.h"
  35 #include "gns.h"
  36 #include "gnunet-service-gns_resolver.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   if (NULL != statistics)
 218   {
 219     GNUNET_STATISTICS_destroy (statistics, GNUNET_NO);
 220     statistics = NULL;
 221   }
 222   if (GNUNET_SCHEDULER_NO_TASK != zone_publish_task)
 223   {
 224     GNUNET_SCHEDULER_cancel (zone_publish_task);
 225     zone_publish_task = GNUNET_SCHEDULER_NO_TASK;
 226   }
 227   if (NULL != namestore_iter)
 228   {
 229     GNUNET_NAMESTORE_zone_iteration_stop (namestore_iter);
 230     namestore_iter = NULL;
 231   }
 232   if (NULL != namestore_handle)
 233   {
 234     GNUNET_NAMESTORE_disconnect (namestore_handle);
 235     namestore_handle = NULL;
 236   }
 237   if (NULL != active_put)
 238   {
 239     GNUNET_DHT_put_cancel (active_put);
 240     active_put = NULL;
 241   }
 242   if (NULL != dht_handle)
 243   {
 244     GNUNET_DHT_disconnect (dht_handle);
 245     dht_handle = NULL;
 246   }
 247 }
 248
 249
 250 /**
 251  * Method called periodically that triggers iteration over authoritative records
 252  *
 253  * @param cls closure
 254  * @param tc task context
 255  */
 256 static void
 257 publish_zone_dht_next (void *cls,
 258                        const struct GNUNET_SCHEDULER_TaskContext *tc)
 259 {
 260   zone_publish_task = GNUNET_SCHEDULER_NO_TASK;
 261   GNUNET_NAMESTORE_zone_iterator_next (namestore_iter);
 262 }
 263
 264
 265 /**
 266  * Periodically iterate over our zone and store everything in dht
 267  *
 268  * @param cls NULL
 269  * @param tc task context
 270  */
 271 static void
 272 publish_zone_dht_start (void *cls,
 273                         const struct GNUNET_SCHEDULER_TaskContext *tc);
 274
 275
 276 /**
 277  * Continuation called from DHT once the PUT operation is done.
 278  *
 279  * @param cls closure, NULL
 280  * @param success #GNUNET_OK on success
 281  */
 282 static void
 283 dht_put_continuation (void *cls,
 284                       int success)
 285 {
 286   struct GNUNET_TIME_Relative next_put_interval;
 287
 288   num_public_records++;
 289   if ( (num_public_records > last_num_public_records) &&
 290        (GNUNET_NO == first_zone_iteration) )
 291   {
 292     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 293                 "Last record count was lower than current record count.  Reducing interval.\n");
 294     put_interval = GNUNET_TIME_relative_divide (zone_publish_time_window,
 295                                                 num_public_records);
 296     next_put_interval = GNUNET_TIME_relative_divide (put_interval,
 297                                                      LATE_ITERATION_SPEEDUP_FACTOR);
 298   }
 299   else
 300     next_put_interval = put_interval;
 301
 302   GNUNET_STATISTICS_set (statistics,
 303                          "Current zone iteration interval (ms)",
 304                          next_put_interval.rel_value_us / 1000LL,
 305                          GNUNET_NO);
 306   zone_publish_task = GNUNET_SCHEDULER_add_delayed (next_put_interval,
 307                                                     &publish_zone_dht_next,
 308                                                     NULL);
 309 }
 310
 311
 312 /**
 313  * Function used to put all records successively into the DHT.
 314  *
 315  * @param cls the closure (NULL)
 316  * @param key the private key of the authority (ours)
 317  * @param name the name of the records, NULL once the iteration is done
 318  * @param rd_count the number of records in @a rd
 319  * @param rd the record data
 320  */
 321 static void
 322 put_gns_record (void *cls,
 323                 const struct GNUNET_CRYPTO_EccPrivateKey *key,
 324                 const char *name,
 325                 unsigned int rd_count,
 326                 const struct GNUNET_NAMESTORE_RecordData *rd)
 327 {
 328   struct GNUNET_NAMESTORE_Block *block;
 329   struct GNUNET_HashCode query;
 330   struct GNUNET_TIME_Absolute expire;
 331   struct GNUNET_TIME_Absolute now;
 332   size_t block_size;
 333   struct GNUNET_NAMESTORE_RecordData rd_public[rd_count];
 334   unsigned int rd_public_count;
 335   unsigned int i;
 336
 337   if (NULL == name)
 338   {
 339     /* we're done with one iteration, calculate when to do the next one */
 340     namestore_iter = NULL;
 341     last_num_public_records = num_public_records;
 342     first_zone_iteration = GNUNET_NO;
 343     if (0 == num_public_records)
 344     {
 345       /**
 346        * If no records are known (startup) or none present
 347        * we can safely set the interval to the value for a single
 348        * record
 349        */
 350       put_interval = zone_publish_time_window;
 351       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG | GNUNET_ERROR_TYPE_BULK,
 352                   "No records in namestore database.\n");
 353     }
 354     else
 355     {
 356       put_interval = GNUNET_TIME_relative_divide (zone_publish_time_window,
 357                                                   num_public_records);
 358     }
 359     put_interval = GNUNET_TIME_relative_max (MINIMUM_ZONE_ITERATION_INTERVAL,
 360                                              put_interval);
 361
 362     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 363                 "Zone iteration finished. Adjusted zone iteration interval to %s\n",
 364                 GNUNET_STRINGS_relative_time_to_string (put_interval, GNUNET_YES));
 365     GNUNET_STATISTICS_set (statistics,
 366                            "Current zone iteration interval (in ms)",
 367                            put_interval.rel_value_us / 1000LL,
 368                            GNUNET_NO);
 369     GNUNET_STATISTICS_update (statistics,
 370                               "Number of zone iterations",
 371                               1,
 372                               GNUNET_NO);
 373     GNUNET_STATISTICS_set (statistics,
 374                            "Number of public records in DHT",
 375                            last_num_public_records,
 376                            GNUNET_NO);
 377     if (0 == num_public_records)
 378       zone_publish_task = GNUNET_SCHEDULER_add_delayed (put_interval,
 379                                                         &publish_zone_dht_start,
 380                                                         NULL);
 381     else
 382       zone_publish_task = GNUNET_SCHEDULER_add_now (&publish_zone_dht_start,
 383                                                     NULL);
 384     return;
 385   }
 386
 387   /* filter out records that are not public, and convert to
 388      absolute expiration time. */
 389   rd_public_count = 0;
 390   now = GNUNET_TIME_absolute_get ();
 391   for (i=0;i<rd_count;i++)
 392     if (0 == (rd[i].flags & (GNUNET_NAMESTORE_RF_PRIVATE |
 393                              GNUNET_NAMESTORE_RF_PENDING)))
 394     {
 395       rd_public[rd_public_count] = rd[i];
 396       if (0 != (rd[i].flags & GNUNET_NAMESTORE_RF_RELATIVE_EXPIRATION))
 397       {
 398         rd_public[rd_public_count].flags &= ~GNUNET_NAMESTORE_RF_RELATIVE_EXPIRATION;
 399         rd_public[rd_public_count].expiration_time += now.abs_value_us;
 400       }
 401       rd_public_count++;
 402     }
 403
 404   /* We got a set of records to publish */
 405   if (0 == rd_public_count)
 406   {
 407     zone_publish_task = GNUNET_SCHEDULER_add_now (&publish_zone_dht_next,
 408                                                    NULL);
 409     return;
 410   }
 411   expire = GNUNET_NAMESTORE_record_get_expiration_time (rd_public_count,
 412                                                         rd_public);
 413   block = GNUNET_NAMESTORE_block_create (key,
 414                                          expire,
 415                                          name,
 416                                          rd_public,
 417                                          rd_public_count);
 418   block_size = ntohl (block->purpose.size)
 419     + sizeof (struct GNUNET_CRYPTO_EccSignature)
 420     + sizeof (struct GNUNET_CRYPTO_EccPublicKey);
 421   GNUNET_NAMESTORE_query_from_private_key (key,
 422                                            name,
 423                                            &query);
 424
 425   active_put = GNUNET_DHT_put (dht_handle, &query,
 426                                DHT_GNS_REPLICATION_LEVEL,
 427                                GNUNET_DHT_RO_DEMULTIPLEX_EVERYWHERE,
 428                                GNUNET_BLOCK_TYPE_GNS_NAMERECORD,
 429                                block_size,
 430                                block,
 431                                expire,
 432                                DHT_OPERATION_TIMEOUT,
 433                                &dht_put_continuation,
 434                                NULL);
 435   if (NULL == active_put)
 436   {
 437     GNUNET_break (0);
 438     dht_put_continuation (NULL, GNUNET_NO);
 439   }
 440   GNUNET_free (block);
 441 }
 442
 443
 444 /**
 445  * Periodically iterate over our zone and store everything in dht
 446  *
 447  * @param cls NULL
 448  * @param tc task context
 449  */
 450 static void
 451 publish_zone_dht_start (void *cls,
 452                         const struct GNUNET_SCHEDULER_TaskContext *tc)
 453 {
 454   zone_publish_task = GNUNET_SCHEDULER_NO_TASK;
 455
 456   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 457               "Scheduling DHT zone update!\n");
 458   /* start counting again */
 459   num_public_records = 0;
 460   namestore_iter = GNUNET_NAMESTORE_zone_iteration_start (namestore_handle,
 461                                                           NULL, /* All zones */
 462                                                           &put_gns_record,
 463                                                           NULL);
 464 }
 465
 466
 467 /* END DHT ZONE PROPAGATION */
 468
 469
 470 /**
 471  * Reply to client with the result from our lookup.
 472  *
 473  * @param cls the closure (our client lookup handle)
 474  * @param rd_count the number of records
 475  * @param rd the record data
 476  */
 477 static void
 478 send_lookup_response (void* cls,
 479                       uint32_t rd_count,
 480                       const struct GNUNET_NAMESTORE_RecordData *rd)
 481 {
 482   struct ClientLookupHandle *clh = cls;
 483   struct GNUNET_GNS_ClientLookupResultMessage *rmsg;
 484   size_t len;
 485
 486   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 487               "Sending `%s' message with %d results\n",
 488               "LOOKUP_RESULT",
 489               rd_count);
 490
 491   len = GNUNET_NAMESTORE_records_get_size (rd_count, rd);
 492   rmsg = GNUNET_malloc (len + sizeof (struct GNUNET_GNS_ClientLookupResultMessage));
 493   rmsg->header.type = htons (GNUNET_MESSAGE_TYPE_GNS_LOOKUP_RESULT);
 494   rmsg->header.size = htons (len + sizeof(struct GNUNET_GNS_ClientLookupResultMessage));
 495   rmsg->id = clh->request_id;
 496   rmsg->rd_count = htonl (rd_count);
 497   GNUNET_NAMESTORE_records_serialize (rd_count, rd, len,
 498                                       (char*) &rmsg[1]);
 499   GNUNET_SERVER_notification_context_unicast (nc,
 500                                               clh->client,
 501                                               &rmsg->header,
 502                                               GNUNET_NO);
 503   GNUNET_free (rmsg);
 504   GNUNET_SERVER_receive_done (clh->client,
 505                               GNUNET_OK);
 506   GNUNET_CONTAINER_DLL_remove (clh_head, clh_tail, clh);
 507   GNUNET_free (clh);
 508   GNUNET_STATISTICS_update (statistics,
 509                             "Completed lookups", 1,
 510                             GNUNET_NO);
 511   GNUNET_STATISTICS_update (statistics,
 512                             "Records resolved",
 513                             rd_count,
 514                             GNUNET_NO);
 515 }
 516
 517
 518 /**
 519  * Handle lookup requests from client
 520  *
 521  * @param cls the closure
 522  * @param client the client
 523  * @param message the message
 524  */
 525 static void
 526 handle_lookup (void *cls,
 527                struct GNUNET_SERVER_Client *client,
 528                const struct GNUNET_MessageHeader *message)
 529 {
 530   char name[GNUNET_DNSPARSER_MAX_NAME_LENGTH + 1];
 531   struct ClientLookupHandle *clh;
 532   char *nameptr = name;
 533   const char *utf_in;
 534   const struct GNUNET_CRYPTO_EccPrivateKey *key;
 535   uint16_t msg_size;
 536   const struct GNUNET_GNS_ClientLookupMessage *sh_msg;
 537
 538   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 539               "Received `%s' message\n",
 540               "LOOKUP");
 541   msg_size = ntohs (message->size);
 542   if (msg_size < sizeof (struct GNUNET_GNS_ClientLookupMessage))
 543   {
 544     GNUNET_break (0);
 545     GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
 546     return;
 547   }
 548   sh_msg = (const struct GNUNET_GNS_ClientLookupMessage *) message;
 549   GNUNET_SERVER_notification_context_add (nc, client);
 550   if (GNUNET_YES == ntohl (sh_msg->have_key))
 551     key = &sh_msg->shorten_key;
 552   else
 553     key = NULL;
 554   utf_in = (const char *) &sh_msg[1];
 555   if ( ('\0' != utf_in[msg_size - sizeof (struct GNUNET_GNS_ClientLookupMessage) - 1]) ||
 556        (strlen (utf_in) > GNUNET_DNSPARSER_MAX_NAME_LENGTH) )
 557   {
 558     GNUNET_break (0);
 559     GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
 560     return;
 561   }
 562   GNUNET_STRINGS_utf8_tolower (utf_in, &nameptr);
 563
 564   clh = GNUNET_new (struct ClientLookupHandle);
 565   GNUNET_SERVER_client_set_user_context (client, clh);
 566   GNUNET_CONTAINER_DLL_insert (clh_head, clh_tail, clh);
 567   clh->client = client;
 568   clh->request_id = sh_msg->id;
 569   if ( (GNUNET_DNSPARSER_TYPE_A == ntohl (sh_msg->type)) &&
 570        (GNUNET_OK != v4_enabled) )
 571   {
 572     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 573                 "LOOKUP: Query for A record but AF_INET not supported!");
 574     send_lookup_response (clh, 0, NULL);
 575     return;
 576   }
 577   if ( (GNUNET_DNSPARSER_TYPE_AAAA == ntohl (sh_msg->type)) &&
 578        (GNUNET_OK != v6_enabled) )
 579   {
 580     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 581                 "LOOKUP: Query for AAAA record but AF_INET6 not supported!");
 582     send_lookup_response (clh, 0, NULL);
 583     return;
 584   }
 585   clh->lookup = GNS_resolver_lookup (&sh_msg->zone,
 586                                      ntohl (sh_msg->type),
 587                                      name,
 588                                      key,
 589                                      ntohl (sh_msg->only_cached),
 590                                      &send_lookup_response, clh);
 591   GNUNET_STATISTICS_update (statistics,
 592                             "Lookup attempts",
 593                             1, GNUNET_NO);
 594 }
 595
 596
 597 /**
 598  * One of our clients disconnected, clean up after it.
 599  *
 600  * @param cls NULL
 601  * @param client the client that disconnected
 602  */
 603 static void
 604 notify_client_disconnect (void *cls,
 605                           struct GNUNET_SERVER_Client *client)
 606 {
 607   struct ClientLookupHandle *clh;
 608
 609   if (NULL == client)
 610     return;
 611   clh = GNUNET_SERVER_client_get_user_context (client, struct ClientLookupHandle);
 612   if (NULL == clh)
 613     return;
 614   GNS_resolver_lookup_cancel (clh->lookup);
 615   GNUNET_CONTAINER_DLL_remove (clh_head, clh_tail, clh);
 616   GNUNET_free (clh);
 617 }
 618
 619
 620 /**
 621  * Process GNS requests.
 622  *
 623  * @param cls closure
 624  * @param server the initialized server
 625  * @param c configuration to use
 626  */
 627 static void
 628 run (void *cls, struct GNUNET_SERVER_Handle *server,
 629      const struct GNUNET_CONFIGURATION_Handle *c)
 630 {
 631   static const struct GNUNET_SERVER_MessageHandler handlers[] = {
 632     { &handle_lookup, NULL, GNUNET_MESSAGE_TYPE_GNS_LOOKUP, 0},
 633     {NULL, NULL, 0, 0}
 634   };
 635   struct GNUNET_CRYPTO_EccPublicKey dns_root;
 636   unsigned long long max_parallel_bg_queries = 0;
 637   char *dns_root_name;
 638
 639   v6_enabled = GNUNET_NETWORK_test_pf (PF_INET6);
 640   v4_enabled = GNUNET_NETWORK_test_pf (PF_INET);
 641
 642   namestore_handle = GNUNET_NAMESTORE_connect (c);
 643   if (NULL == namestore_handle)
 644   {
 645     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
 646                 _("Failed to connect to the namestore!\n"));
 647     GNUNET_SCHEDULER_shutdown ();
 648     return;
 649   }
 650
 651   put_interval = INITIAL_PUT_INTERVAL;
 652   zone_publish_time_window = DEFAULT_ZONE_PUBLISH_TIME_WINDOW;
 653
 654   if (GNUNET_OK ==
 655       GNUNET_CONFIGURATION_get_value_time (c, "gns",
 656                                            "ZONE_PUBLISH_TIME_WINDOW",
 657                                            &zone_publish_time_window))
 658   {
 659     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 660                 "Time window for zone iteration: %s\n",
 661                 GNUNET_STRINGS_relative_time_to_string (zone_publish_time_window, GNUNET_YES));
 662   }
 663   if (GNUNET_OK ==
 664       GNUNET_CONFIGURATION_get_value_number (c, "gns",
 665                                             "MAX_PARALLEL_BACKGROUND_QUERIES",
 666                                             &max_parallel_bg_queries))
 667   {
 668     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 669                 "Number of allowed parallel background queries: %llu\n",
 670                 max_parallel_bg_queries);
 671   }
 672
 673   if (GNUNET_OK ==
 674       GNUNET_CONFIGURATION_get_value_time (c, "gns",
 675                                            "DEFAULT_LOOKUP_TIMEOUT",
 676                                            &default_lookup_timeout))
 677   {
 678     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 679                 "Default lookup timeout: %s\n",
 680                 GNUNET_STRINGS_relative_time_to_string (default_lookup_timeout,
 681                                                         GNUNET_YES));
 682   }
 683
 684   dht_handle = GNUNET_DHT_connect (c,
 685                                    (unsigned int) max_parallel_bg_queries);
 686   if (NULL == dht_handle)
 687   {
 688     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
 689                 _("Could not connect to DHT!\n"));
 690     GNUNET_SCHEDULER_add_now (&shutdown_task, NULL);
 691     return;
 692   }
 693
 694   if (GNUNET_OK ==
 695       GNUNET_CONFIGURATION_get_value_string (c, "gns", "DNS_ROOT",
 696                                              &dns_root_name))
 697   {
 698     if (GNUNET_OK !=
 699         GNUNET_CRYPTO_ecc_public_key_from_string (dns_root_name,
 700                                                   strlen (dns_root_name),
 701                                                   &dns_root))
 702     {
 703       GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
 704                                  "gns", "DNS_ROOT",
 705                                  _("valid public key required"));
 706       GNUNET_SCHEDULER_add_now (&shutdown_task, NULL);
 707       GNUNET_free (dns_root_name);
 708       return;
 709     }
 710     GNUNET_log (GNUNET_ERROR_TYPE_INFO,
 711                 "DNS hijacking with root `%s' enabled. Connecting to DNS service.\n",
 712                 dns_root_name);
 713     GNUNET_free (dns_root_name);
 714     if (GNUNET_SYSERR ==
 715         GNS_interceptor_init (&dns_root, c))
 716     {
 717       GNUNET_SCHEDULER_add_now (&shutdown_task, NULL);
 718       return;
 719     }
 720   }
 721   /* FIXME: install client disconnect handle to clean up pending
 722      lookups on client disconnect! */
 723   GNS_resolver_init (namestore_handle, dht_handle,
 724                      c,
 725                      max_parallel_bg_queries);
 726   GNUNET_SERVER_disconnect_notify (server,
 727                                    &notify_client_disconnect,
 728                                    NULL);
 729   /* Schedule periodic put for our records. */
 730   first_zone_iteration = GNUNET_YES;
 731   GNUNET_SERVER_add_handlers (server, handlers);
 732   statistics = GNUNET_STATISTICS_create ("gns", c);
 733   nc = GNUNET_SERVER_notification_context_create (server, 1);
 734   zone_publish_task = GNUNET_SCHEDULER_add_now (&publish_zone_dht_start,
 735                                                 NULL);
 736   GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL,
 737                                 &shutdown_task, NULL);
 738 }
 739
 740
 741 /**
 742  * The main function for the GNS service.
 743  *
 744  * @param argc number of arguments from the command line
 745  * @param argv command line arguments
 746  * @return 0 ok, 1 on error
 747  */
 748 int
 749 main (int argc, char *const *argv)
 750 {
 751   int ret;
 752
 753   ret =
 754       (GNUNET_OK ==
 755        GNUNET_SERVICE_run (argc, argv, "gns", GNUNET_SERVICE_OPTION_NONE, &run,
 756                            NULL)) ? 0 : 1;
 757   return ret;
 758 }
 759
 760 /* end of gnunet-service-gns.c */