src/gns/gnunet-service-gns.c

   1 /*
   2      This file is part of GNUnet.
   3      (C) 2009, 2010, 2011 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 /**
  22  * @file gns/gnunet-service-gns.c
  23  * @brief GNUnet GNS service
  24  * @author Martin Schanzenbach
  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 "gns.h"
  35
  36
  37 /* TODO into gnunet_protocols */
  38 #define GNUNET_MESSAGE_TYPE_GNS_CLIENT_LOOKUP 23
  39 #define GNUNET_MESSAGE_TYPE_GNS_CLIENT_RESULT 24
  40
  41 struct GNUNET_GNS_QueryRecordList
  42 {
  43   /**
  44    * DLL
  45    */
  46   struct GNUNET_GNS_QueryRecordList * next;
  47   struct GNUNET_GNS_QueryRecordList * prev;
  48
  49   struct GNUNET_DNSPARSER_Record * record;
  50 };
  51
  52 /**
  53  * A result list for namestore queries
  54  */
  55 struct GNUNET_GNS_PendingQuery
  56 {
  57   /* the answer packet */
  58   struct GNUNET_DNSPARSER_Packet *answer;
  59
  60   /* records to put into answer packet */
  61   struct GNUNET_GNS_QueryRecordList * records_head;
  62   struct GNUNET_GNS_QueryRecordList * records_tail;
  63
  64   int num_records;
  65   int num_authority_records; //FIXME are all of our replies auth?
  66
  67   char *name;
  68   uint16_t type;
  69   /* the dns request id */
  70   int id; // FIXME can handle->request_id also be used here?
  71
  72   /* the request handle to reply to */
  73   struct GNUNET_DNS_RequestHandle *request_handle;
  74
  75   /* hast this query been answered? */
  76   int answered;
  77 };
  78
  79
  80 /**
  81  * Our handle to the DNS handler library
  82  */
  83 struct GNUNET_DNS_Handle *dns_handle;
  84
  85 /**
  86  * Our handle to the DHT
  87  */
  88 struct GNUNET_DHT_Handle *dht_handle;
  89
  90 /**
  91  * Our handle to the namestore service
  92  */
  93 struct GNUNET_NAMESTORE_Handle *namestore_handle;
  94
  95 /**
  96  * The configuration the GNS service is running with
  97  */
  98 const struct GNUNET_CONFIGURATION_Handle *GNS_cfg;
  99
 100 /**
 101  * Our notification context.
 102  */
 103 static struct GNUNET_SERVER_NotificationContext *nc;
 104
 105 /**
 106  * Our zone hash
 107  */
 108 const GNUNET_HashCode *my_zone;
 109
 110 /**
 111  * Task run during shutdown.
 112  *
 113  * @param cls unused
 114  * @param tc unused
 115  */
 116 static void
 117 shutdown_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
 118 {
 119   GNUNET_DNS_disconnect(dns_handle);
 120   GNUNET_NAMESTORE_disconnect(namestore_handle, 0);
 121 }
 122
 123 /**
 124  * Phase 2 of resolution.
 125  */
 126 void
 127 lookup_dht(struct GNUNET_GNS_PendingQuery *answer)
 128 {
 129 }
 130
 131 void
 132 reply_to_dns(struct GNUNET_GNS_PendingQuery *answer)
 133 {
 134   struct GNUNET_GNS_QueryRecordList *i;
 135   struct GNUNET_DNSPARSER_Packet *packet;
 136   struct GNUNET_DNSPARSER_Flags dnsflags;
 137   int j;
 138   size_t len;
 139   int ret;
 140   char *buf;
 141
 142   packet = GNUNET_malloc(sizeof(struct GNUNET_DNSPARSER_Packet));
 143   packet->answers =
 144     GNUNET_malloc(sizeof(struct GNUNET_DNSPARSER_Record) * answer->num_records);
 145
 146   len = sizeof(struct GNUNET_DNSPARSER_Record*);
 147   j = 0;
 148   for (i=answer->records_head; i != NULL; i=i->next)
 149   {
 150     GNUNET_log(GNUNET_ERROR_TYPE_INFO,
 151                "Adding %s to DNS response\n", i->record->name);
 152     memcpy(&packet->answers[j],
 153            i->record,
 154            sizeof (struct GNUNET_DNSPARSER_Record));
 155     GNUNET_free(i->record);
 156     j++;
 157   }
 158   GNUNET_log(GNUNET_ERROR_TYPE_INFO, "after memcpy\n");
 159   /* FIXME how to handle auth, additional etc */
 160   packet->num_answers = answer->num_records;
 161   packet->num_authority_records = answer->num_authority_records;
 162
 163   dnsflags.authoritative_answer = 1;
 164   dnsflags.opcode = GNUNET_DNSPARSER_OPCODE_QUERY;
 165   dnsflags.return_code = GNUNET_DNSPARSER_RETURN_CODE_NO_ERROR; //not sure
 166   dnsflags.query_or_response = 1;
 167   packet->flags = dnsflags;
 168
 169   packet->id = answer->id;
 170   ret = GNUNET_DNSPARSER_pack (packet,
 171                                1024, /* FIXME magic from dns redirector */
 172                                &buf,
 173                                &len);
 174   GNUNET_log(GNUNET_ERROR_TYPE_INFO,
 175              "Built DNS response! (ret=%d)\n", ret);
 176   if (ret == GNUNET_OK)
 177   {
 178     GNUNET_log(GNUNET_ERROR_TYPE_INFO,
 179                "Answering DNS request\n");
 180     GNUNET_DNS_request_answer(answer->request_handle,
 181                               len,
 182                               buf);
 183     GNUNET_free(answer);
 184     GNUNET_log(GNUNET_ERROR_TYPE_INFO, "Answered DNS request\n");
 185     //FIXME return code, free datastructures
 186   }
 187   else
 188   {
 189     GNUNET_log(GNUNET_ERROR_TYPE_ERROR,
 190                "Error building DNS response! (ret=%d)", ret);
 191   }
 192 }
 193
 194 static void
 195 process_ns_result(void* cls, const GNUNET_HashCode *zone,
 196                   const char *name, uint32_t record_type,
 197                   struct GNUNET_TIME_Absolute expiration,
 198                   enum GNUNET_NAMESTORE_RecordFlags flags,
 199                   const struct GNUNET_NAMESTORE_SignatureLocation *sig_loc,
 200                   size_t size, const void *data)
 201 {
 202   struct GNUNET_GNS_PendingQuery *query;
 203   struct GNUNET_GNS_QueryRecordList *qrecord;
 204   struct GNUNET_DNSPARSER_Record *record;
 205   query = (struct GNUNET_GNS_PendingQuery *) cls;
 206
 207
 208   if (NULL == data)
 209   {
 210     /**
 211      * Last result received (or none)
 212      * Do we have what we need to answer?
 213      * If not -> DHT Phase
 214      * FIXME free memory
 215      */
 216     GNUNET_log(GNUNET_ERROR_TYPE_INFO,
 217                "Namestore lookup terminated. (answered=%d)", query->answered);
 218
 219     if (query->answered)
 220       reply_to_dns(query);
 221     else
 222       lookup_dht(query); //TODO
 223
 224   }
 225   else
 226   {
 227     /**
 228      * New result
 229      */
 230     GNUNET_log(GNUNET_ERROR_TYPE_INFO,
 231                "Processing additional result %s from namestore\n", name);
 232
 233     qrecord = GNUNET_malloc(sizeof(struct GNUNET_GNS_QueryRecordList));
 234     record = GNUNET_malloc(sizeof(struct GNUNET_DNSPARSER_Record));
 235     qrecord->record = record;
 236
 237     record->name = (char*)name;
 238     /* FIXME for gns records this requires the dnsparser to be modified!
 239      * or use RAW
 240      * maybe store record data appropriately in namestore to avoid this
 241      * huge switch?
 242      **/
 243     if (record_type == GNUNET_DNSPARSER_TYPE_A)
 244     {
 245       record->data.raw.data = (char*)data;
 246       record->data.raw.data_len = size;
 247     }
 248     record->expiration_time = expiration;
 249     record->type = record_type;
 250     record->class = GNUNET_DNSPARSER_CLASS_INTERNET; /* srsly? */
 251
 252     if (flags == GNUNET_NAMESTORE_RF_AUTHORITY)
 253     {
 254       //query->num_authority_records++;
 255     }
 256
 257     if ((0 == strcmp(query->name , name)) &&
 258         (query->type == record_type))
 259     {
 260       GNUNET_log(GNUNET_ERROR_TYPE_INFO, "Found answer to query!\n");
 261       query->answered = 1;
 262     }
 263
 264     query->num_records++;
 265
 266     //FIXME watch for leaks
 267     GNUNET_CONTAINER_DLL_insert(query->records_head,
 268                                 query->records_tail,
 269                                 qrecord);
 270   }
 271 }
 272
 273
 274 /**
 275  * Phase 1 of name resolution: Lookup local namestore
 276  *
 277  * @param name the name to look up
 278  * @param id the id of the dns request (for the reply)
 279  * @param type the record type to look for
 280  */
 281 void
 282 lookup_namestore(struct GNUNET_DNS_RequestHandle *rh,
 283                  char* name, uint16_t id, uint16_t type)
 284 {
 285   struct GNUNET_GNS_PendingQuery *answer;
 286
 287   /**
 288    * Do db lookup here. Make dht lookup if necessary
 289    * FIXME for now only local lookups for our zone!
 290    */
 291   GNUNET_log (GNUNET_ERROR_TYPE_INFO, "This is .gnunet (%s)!\n", name);
 292   answer = GNUNET_malloc(sizeof (struct GNUNET_GNS_PendingQuery));
 293   answer->id = id;
 294   answer->name = name;
 295   answer->type =type;
 296   answer->request_handle = rh;
 297
 298   GNUNET_NAMESTORE_lookup_name(namestore_handle,
 299                                my_zone,
 300                                name,
 301                                type,
 302                                &process_ns_result,
 303                                answer);
 304 }
 305
 306 /**
 307  * The DNS request handler
 308  *
 309  * @param cls closure
 310  * @param rh request handle to user for reply
 311  * @param request_length number of bytes in request
 312  * @param request udp payload of the DNS request
 313  */
 314 void
 315 handle_dns_request(void *cls,
 316                    struct GNUNET_DNS_RequestHandle *rh,
 317                    size_t request_length,
 318                    const char *request)
 319 {
 320   /**
 321    * parse request for tld
 322    */
 323   struct GNUNET_DNSPARSER_Packet *p;
 324   int namelen;
 325   int i;
 326   char *tail;
 327
 328   GNUNET_log (GNUNET_ERROR_TYPE_INFO, "hijacked a request...processing\n");
 329   p = GNUNET_DNSPARSER_parse (request, request_length);
 330
 331   if (NULL == p)
 332   {
 333     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
 334                 "Received malformed DNS packet, leaving it untouched\n");
 335     GNUNET_DNS_request_forward (rh);
 336     return;
 337   }
 338
 339   /**
 340    * Check tld and decide if we or
 341    * legacy dns is responsible
 342    */
 343   for (i=0;i<p->num_queries;i++)
 344   {
 345     namelen = strlen(p->queries[i].name);
 346
 347     if (namelen < 7) /* this can't be .gnunet */
 348       continue;
 349     /**
 350      * Move our tld/root to config file
 351      * Generate fake DNS reply that replaces .gnunet with .org for testing?
 352      */
 353     tail = p->queries[i].name+(namelen-7);
 354     if (0 == strcmp(tail, ".gnunet"))
 355     {
 356       /* FIXME we need to answer to ALL queries in ONE response...
 357        * What happens if some requests should be handles by us and
 358        * others by DNS?
 359        * Like this we only answer one...
 360        */
 361       lookup_namestore(rh, p->queries[i].name, p->id, p->queries[i].type);
 362     }
 363     else
 364     {
 365       /**
 366        * This request does not concern us. Forward to real DNS.
 367        */
 368       GNUNET_log(GNUNET_ERROR_TYPE_INFO,
 369                  "Request for %s is forwarded to DNS\n", p->queries[i].name);
 370       GNUNET_DNS_request_forward (rh);
 371     }
 372   }
 373 }
 374
 375 /*TODO*/
 376 static void
 377 handle_client_record_lookup(void *cls,
 378                             struct GNUNET_SERVER_Client *client,
 379                             const struct GNUNET_MessageHeader *message)
 380 {
 381 }
 382
 383 /**
 384  * test function
 385  */
 386 void
 387 put_some_records(void)
 388 {
 389   /* put a few records into namestore */
 390   char* ipA = "1.2.3.4";
 391   char* ipB = "5.6.7.8";
 392   struct in_addr *alice = GNUNET_malloc(sizeof(struct in_addr));
 393   struct in_addr *bob = GNUNET_malloc(sizeof(struct in_addr));
 394   GNUNET_assert(1 == inet_pton (AF_INET, ipA, alice));
 395   GNUNET_assert(1 == inet_pton (AF_INET, ipB, bob));
 396   GNUNET_NAMESTORE_record_put (namestore_handle,
 397                                my_zone,
 398                                "alice.gnunet",
 399                                GNUNET_GNS_RECORD_TYPE_A,
 400                                GNUNET_TIME_absolute_get_forever(),
 401                                GNUNET_NAMESTORE_RF_AUTHORITY,
 402                                NULL, //sig loc
 403                                sizeof(struct in_addr),
 404                                alice,
 405                                NULL,
 406                                NULL);
 407   GNUNET_NAMESTORE_record_put (namestore_handle,
 408                                my_zone,
 409                                "bob.gnunet",
 410                                GNUNET_GNS_RECORD_TYPE_A,
 411                                GNUNET_TIME_absolute_get_forever(),
 412                                GNUNET_NAMESTORE_RF_AUTHORITY,
 413                                NULL, //sig loc
 414                                sizeof(struct in_addr),
 415                                bob,
 416                                NULL,
 417                                NULL);
 418 }
 419
 420 /**
 421  * Process GNS requests.
 422  *
 423  * @param cls closure
 424  * @param server the initialized server
 425  * @param c configuration to use
 426  */
 427 static void
 428 run (void *cls, struct GNUNET_SERVER_Handle *server,
 429      const struct GNUNET_CONFIGURATION_Handle *c)
 430 {
 431   /* The IPC message types */
 432   static const struct GNUNET_SERVER_MessageHandler handlers[] = {
 433     /* callback, cls, type, size */
 434     {&handle_client_record_lookup, NULL, GNUNET_MESSAGE_TYPE_GNS_CLIENT_LOOKUP,
 435       0},
 436     {NULL, NULL, 0, 0}
 437   };
 438
 439   nc = GNUNET_SERVER_notification_context_create (server, 1);
 440
 441   /* FIXME - do some config parsing
 442    *       - Maybe only hijack dns if option is set (HIJACK_DNS=1)
 443    */
 444
 445   GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL, &shutdown_task,
 446                                 NULL);
 447   /**
 448    * Do gnunet dns init here
 449    */
 450   dns_handle = GNUNET_DNS_connect(c,
 451                                   GNUNET_DNS_FLAG_PRE_RESOLUTION,
 452                                   &handle_dns_request, /* rh */
 453                                   NULL); /* Closure */
 454
 455   if (NULL == dns_handle)
 456   {
 457     GNUNET_log(GNUNET_ERROR_TYPE_ERROR,
 458                "Failed to connect to the dnsservice!\n");
 459   }
 460
 461   /**
 462    * handle to our local namestore
 463    */
 464   namestore_handle = GNUNET_NAMESTORE_connect(c);
 465
 466   if (NULL == namestore_handle)
 467   {
 468     //FIXME do error handling;
 469     GNUNET_log(GNUNET_ERROR_TYPE_ERROR,
 470                "Failed to connect to the namestore!\n");
 471   }
 472
 473   /**
 474    * handle to the dht
 475    */
 476   dht_handle = GNUNET_DHT_connect(c, 1); //FIXME get ht_len from cfg
 477
 478   if (NULL == dht_handle)
 479   {
 480     GNUNET_log(GNUNET_ERROR_TYPE_ERROR, "Could not connect to DHT!\n");
 481   }
 482
 483   put_some_records();
 484
 485   GNUNET_SERVER_add_handlers (server, handlers);
 486   /**
 487    * Esp the lookup would require to keep track of the clients' context
 488    * See dht.
 489    * GNUNET_SERVER_disconnect_notify (server, &client_disconnect, NULL);
 490    **/
 491 }
 492
 493
 494 /**
 495  * The main function for the GNS service.
 496  *
 497  * @param argc number of arguments from the command line
 498  * @param argv command line arguments
 499  * @return 0 ok, 1 on error
 500  */
 501 int
 502 main (int argc, char *const *argv)
 503 {
 504   int ret;
 505
 506   ret =
 507       (GNUNET_OK ==
 508        GNUNET_SERVICE_run (argc, argv, "gns", GNUNET_SERVICE_OPTION_NONE, &run,
 509                            NULL)) ? 0 : 1;
 510   return ret;
 511 }
 512
 513 /* end of gnunet-service-gns.c */