src/dht/gnunet-service-dht_neighbours.c

   1 /*
   2      This file is part of GNUnet.
   3      Copyright (C) 2009-2017 GNUnet e.V.
   4
   5      GNUnet is free software: you can redistribute it and/or modify it
   6      under the terms of the GNU Affero General Public License as published
   7      by the Free Software Foundation, either version 3 of the License,
   8      or (at your 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      Affero General Public License for more details.
  14
  15      You should have received a copy of the GNU Affero General Public License
  16      along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17
  18      SPDX-License-Identifier: AGPL3.0-or-later
  19 */
  20
  21 /**
  22  * @file dht/gnunet-service-dht_neighbours.c
  23  * @brief GNUnet DHT service's bucket and neighbour management code
  24  * @author Christian Grothoff
  25  * @author Nathan Evans
  26  */
  27 #include "platform.h"
  28 #include "gnunet_util_lib.h"
  29 #include "gnunet_block_lib.h"
  30 #include "gnunet_hello_lib.h"
  31 #include "gnunet_constants.h"
  32 #include "gnunet_protocols.h"
  33 #include "gnunet_nse_service.h"
  34 #include "gnunet_ats_service.h"
  35 #include "gnunet_core_service.h"
  36 #include "gnunet_datacache_lib.h"
  37 #include "gnunet_transport_service.h"
  38 #include "gnunet_hello_lib.h"
  39 #include "gnunet_dht_service.h"
  40 #include "gnunet_statistics_service.h"
  41 #include "gnunet-service-dht.h"
  42 #include "gnunet-service-dht_datacache.h"
  43 #include "gnunet-service-dht_hello.h"
  44 #include "gnunet-service-dht_neighbours.h"
  45 #include "gnunet-service-dht_nse.h"
  46 #include "gnunet-service-dht_routing.h"
  47 #include "dht.h"
  48
  49 #define LOG_TRAFFIC(kind,...) GNUNET_log_from (kind, "dht-traffic",__VA_ARGS__)
  50
  51 /**
  52  * Enable slow sanity checks to debug issues.
  53  */
  54 #define SANITY_CHECKS 1
  55
  56 /**
  57  * How many buckets will we allow total.
  58  */
  59 #define MAX_BUCKETS sizeof (struct GNUNET_HashCode) * 8
  60
  61 /**
  62  * What is the maximum number of peers in a given bucket.
  63  */
  64 #define DEFAULT_BUCKET_SIZE 8
  65
  66 /**
  67  * Desired replication level for FIND PEER requests
  68  */
  69 #define FIND_PEER_REPLICATION_LEVEL 4
  70
  71 /**
  72  * Maximum allowed replication level for all requests.
  73  */
  74 #define MAXIMUM_REPLICATION_LEVEL 16
  75
  76 /**
  77  * Maximum allowed number of pending messages per peer.
  78  */
  79 #define MAXIMUM_PENDING_PER_PEER 64
  80
  81 /**
  82  * How long at least to wait before sending another find peer request.
  83  */
  84 #define DHT_MINIMUM_FIND_PEER_INTERVAL GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_SECONDS, 30)
  85
  86 /**
  87  * How long at most to wait before sending another find peer request.
  88  */
  89 #define DHT_MAXIMUM_FIND_PEER_INTERVAL GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_MINUTES, 10)
  90
  91 /**
  92  * How long at most to wait for transmission of a GET request to another peer?
  93  */
  94 #define GET_TIMEOUT GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_MINUTES, 2)
  95
  96 /**
  97  * Hello address expiration
  98  */
  99 extern struct GNUNET_TIME_Relative hello_expiration;
 100
 101
 102 GNUNET_NETWORK_STRUCT_BEGIN
 103
 104 /**
 105  * P2P PUT message
 106  */
 107 struct PeerPutMessage
 108 {
 109   /**
 110    * Type: #GNUNET_MESSAGE_TYPE_DHT_P2P_PUT
 111    */
 112   struct GNUNET_MessageHeader header;
 113
 114   /**
 115    * Processing options
 116    */
 117   uint32_t options GNUNET_PACKED;
 118
 119   /**
 120    * Content type.
 121    */
 122   uint32_t type GNUNET_PACKED;
 123
 124   /**
 125    * Hop count
 126    */
 127   uint32_t hop_count GNUNET_PACKED;
 128
 129   /**
 130    * Replication level for this message
 131    */
 132   uint32_t desired_replication_level GNUNET_PACKED;
 133
 134   /**
 135    * Length of the PUT path that follows (if tracked).
 136    */
 137   uint32_t put_path_length GNUNET_PACKED;
 138
 139   /**
 140    * When does the content expire?
 141    */
 142   struct GNUNET_TIME_AbsoluteNBO expiration_time;
 143
 144   /**
 145    * Bloomfilter (for peer identities) to stop circular routes
 146    */
 147   char bloomfilter[DHT_BLOOM_SIZE];
 148
 149   /**
 150    * The key we are storing under.
 151    */
 152   struct GNUNET_HashCode key;
 153
 154   /* put path (if tracked) */
 155
 156   /* Payload */
 157
 158 };
 159
 160
 161 /**
 162  * P2P Result message
 163  */
 164 struct PeerResultMessage
 165 {
 166   /**
 167    * Type: #GNUNET_MESSAGE_TYPE_DHT_P2P_RESULT
 168    */
 169   struct GNUNET_MessageHeader header;
 170
 171   /**
 172    * Content type.
 173    */
 174   uint32_t type GNUNET_PACKED;
 175
 176   /**
 177    * Length of the PUT path that follows (if tracked).
 178    */
 179   uint32_t put_path_length GNUNET_PACKED;
 180
 181   /**
 182    * Length of the GET path that follows (if tracked).
 183    */
 184   uint32_t get_path_length GNUNET_PACKED;
 185
 186   /**
 187    * When does the content expire?
 188    */
 189   struct GNUNET_TIME_AbsoluteNBO expiration_time;
 190
 191   /**
 192    * The key of the corresponding GET request.
 193    */
 194   struct GNUNET_HashCode key;
 195
 196   /* put path (if tracked) */
 197
 198   /* get path (if tracked) */
 199
 200   /* Payload */
 201
 202 };
 203
 204
 205 /**
 206  * P2P GET message
 207  */
 208 struct PeerGetMessage
 209 {
 210   /**
 211    * Type: #GNUNET_MESSAGE_TYPE_DHT_P2P_GET
 212    */
 213   struct GNUNET_MessageHeader header;
 214
 215   /**
 216    * Processing options
 217    */
 218   uint32_t options GNUNET_PACKED;
 219
 220   /**
 221    * Desired content type.
 222    */
 223   uint32_t type GNUNET_PACKED;
 224
 225   /**
 226    * Hop count
 227    */
 228   uint32_t hop_count GNUNET_PACKED;
 229
 230   /**
 231    * Desired replication level for this request.
 232    */
 233   uint32_t desired_replication_level GNUNET_PACKED;
 234
 235   /**
 236    * Size of the extended query.
 237    */
 238   uint32_t xquery_size;
 239
 240   /**
 241    * Bloomfilter mutator.
 242    */
 243   uint32_t bf_mutator;
 244
 245   /**
 246    * Bloomfilter (for peer identities) to stop circular routes
 247    */
 248   char bloomfilter[DHT_BLOOM_SIZE];
 249
 250   /**
 251    * The key we are looking for.
 252    */
 253   struct GNUNET_HashCode key;
 254
 255   /* xquery */
 256
 257   /* result bloomfilter */
 258
 259 };
 260 GNUNET_NETWORK_STRUCT_END
 261
 262
 263 /**
 264  * Entry for a peer in a bucket.
 265  */
 266 struct PeerInfo
 267 {
 268   /**
 269    * Next peer entry (DLL)
 270    */
 271   struct PeerInfo *next;
 272
 273   /**
 274    *  Prev peer entry (DLL)
 275    */
 276   struct PeerInfo *prev;
 277
 278   /**
 279    * Handle for sending messages to this peer.
 280    */
 281   struct GNUNET_MQ_Handle *mq;
 282
 283   /**
 284    * What is the identity of the peer?
 285    */
 286   const struct GNUNET_PeerIdentity *id;
 287
 288   /**
 289    * Hash of @e id.
 290    */
 291   struct GNUNET_HashCode phash;
 292
 293   /**
 294    * Which bucket is this peer in?
 295    */
 296   int peer_bucket;
 297
 298 };
 299
 300
 301 /**
 302  * Peers are grouped into buckets.
 303  */
 304 struct PeerBucket
 305 {
 306   /**
 307    * Head of DLL
 308    */
 309   struct PeerInfo *head;
 310
 311   /**
 312    * Tail of DLL
 313    */
 314   struct PeerInfo *tail;
 315
 316   /**
 317    * Number of peers in the bucket.
 318    */
 319   unsigned int peers_size;
 320 };
 321
 322
 323 /**
 324  * Information about a peer that we would like to connect to.
 325  */
 326 struct ConnectInfo
 327 {
 328
 329   /**
 330    * Handle to active HELLO offer operation, or NULL.
 331    */
 332   struct GNUNET_TRANSPORT_OfferHelloHandle *oh;
 333
 334   /**
 335    * Handle to active connectivity suggestion operation, or NULL.
 336    */
 337   struct GNUNET_ATS_ConnectivitySuggestHandle *sh;
 338
 339   /**
 340    * How much would we like to connect to this peer?
 341    */
 342   uint32_t strength;
 343 };
 344
 345
 346 /**
 347  * Do we cache all results that we are routing in the local datacache?
 348  */
 349 static int cache_results;
 350
 351 /**
 352  * Should routing details be logged to stderr (for debugging)?
 353  */
 354 static int log_route_details_stderr;
 355
 356 /**
 357  * The lowest currently used bucket, initially 0 (for 0-bits matching bucket).
 358  */
 359 static unsigned int closest_bucket;
 360
 361 /**
 362  * How many peers have we added since we sent out our last
 363  * find peer request?
 364  */
 365 static unsigned int newly_found_peers;
 366
 367 /**
 368  * Option for testing that disables the 'connect' function of the DHT.
 369  */
 370 static int disable_try_connect;
 371
 372 /**
 373  * The buckets.  Array of size #MAX_BUCKETS.  Offset 0 means 0 bits matching.
 374  */
 375 static struct PeerBucket k_buckets[MAX_BUCKETS];
 376
 377 /**
 378  * Hash map of all CORE-connected peers, for easy removal from
 379  * #k_buckets on disconnect.  Values are of type `struct PeerInfo`.
 380  */
 381 static struct GNUNET_CONTAINER_MultiPeerMap *all_connected_peers;
 382
 383 /**
 384  * Hash map of all peers we would like to be connected to.
 385  * Values are of type `struct ConnectInfo`.
 386  */
 387 static struct GNUNET_CONTAINER_MultiPeerMap *all_desired_peers;
 388
 389 /**
 390  * Maximum size for each bucket.
 391  */
 392 static unsigned int bucket_size = DEFAULT_BUCKET_SIZE;
 393
 394 /**
 395  * Task that sends FIND PEER requests.
 396  */
 397 static struct GNUNET_SCHEDULER_Task *find_peer_task;
 398
 399 /**
 400  * Identity of this peer.
 401  */
 402 static struct GNUNET_PeerIdentity my_identity;
 403
 404 /**
 405  * Hash of the identity of this peer.
 406  */
 407 struct GNUNET_HashCode my_identity_hash;
 408
 409 /**
 410  * Handle to CORE.
 411  */
 412 static struct GNUNET_CORE_Handle *core_api;
 413
 414 /**
 415  * Handle to ATS connectivity.
 416  */
 417 static struct GNUNET_ATS_ConnectivityHandle *ats_ch;
 418
 419
 420 /**
 421  * Find the optimal bucket for this key.
 422  *
 423  * @param hc the hashcode to compare our identity to
 424  * @return the proper bucket index, or #GNUNET_SYSERR
 425  *         on error (same hashcode)
 426  */
 427 static int
 428 find_bucket (const struct GNUNET_HashCode *hc)
 429 {
 430   unsigned int bits;
 431
 432   bits = GNUNET_CRYPTO_hash_matching_bits (&my_identity_hash, hc);
 433   if (bits == MAX_BUCKETS)
 434   {
 435     /* How can all bits match? Got my own ID? */
 436     GNUNET_break (0);
 437     return GNUNET_SYSERR;
 438   }
 439   return MAX_BUCKETS - bits - 1;
 440 }
 441
 442
 443 /**
 444  * Function called when #GNUNET_TRANSPORT_offer_hello() is done.
 445  * Clean up the "oh" field in the @a cls
 446  *
 447  * @param cls a `struct ConnectInfo`
 448  */
 449 static void
 450 offer_hello_done (void *cls)
 451 {
 452   struct ConnectInfo *ci = cls;
 453
 454   ci->oh = NULL;
 455 }
 456
 457
 458 /**
 459  * Function called for all entries in #all_desired_peers to clean up.
 460  *
 461  * @param cls NULL
 462  * @param peer peer the entry is for
 463  * @param value the value to remove
 464  * @return #GNUNET_YES
 465  */
 466 static int
 467 free_connect_info (void *cls,
 468                    const struct GNUNET_PeerIdentity *peer,
 469                    void *value)
 470 {
 471   struct ConnectInfo *ci = value;
 472
 473  (void) cls;
 474   GNUNET_assert (GNUNET_YES ==
 475                  GNUNET_CONTAINER_multipeermap_remove (all_desired_peers,
 476                                                        peer,
 477                                                        ci));
 478   if (NULL != ci->sh)
 479   {
 480     GNUNET_ATS_connectivity_suggest_cancel (ci->sh);
 481     ci->sh = NULL;
 482   }
 483   if (NULL != ci->oh)
 484   {
 485     GNUNET_TRANSPORT_offer_hello_cancel (ci->oh);
 486     ci->oh = NULL;
 487   }
 488   GNUNET_free (ci);
 489   return GNUNET_YES;
 490 }
 491
 492
 493 /**
 494  * Consider if we want to connect to a given peer, and if so
 495  * let ATS know.  If applicable, the HELLO is offered to the
 496  * TRANSPORT service.
 497  *
 498  * @param pid peer to consider connectivity requirements for
 499  * @param h a HELLO message, or NULL
 500  */
 501 static void
 502 try_connect (const struct GNUNET_PeerIdentity *pid,
 503              const struct GNUNET_MessageHeader *h)
 504 {
 505   int bucket;
 506   struct GNUNET_HashCode pid_hash;
 507   struct ConnectInfo *ci;
 508   uint32_t strength;
 509
 510   GNUNET_CRYPTO_hash (pid,
 511                       sizeof (struct GNUNET_PeerIdentity),
 512                       &pid_hash);
 513   bucket = find_bucket (&pid_hash);
 514   if (bucket < 0)
 515     return; /* self? */
 516   ci = GNUNET_CONTAINER_multipeermap_get (all_desired_peers,
 517                                           pid);
 518
 519   if (k_buckets[bucket].peers_size < bucket_size)
 520     strength = (bucket_size - k_buckets[bucket].peers_size) * bucket;
 521   else
 522     strength = bucket; /* minimum value of connectivity */
 523   if (GNUNET_YES ==
 524       GNUNET_CONTAINER_multipeermap_contains (all_connected_peers,
 525                                               pid))
 526     strength *= 2; /* double for connected peers */
 527   else if (k_buckets[bucket].peers_size > bucket_size)
 528     strength = 0; /* bucket full, we really do not care about more */
 529
 530   if ( (0 == strength) &&
 531        (NULL != ci) )
 532   {
 533     /* release request */
 534     GNUNET_assert (GNUNET_YES ==
 535                    free_connect_info (NULL,
 536                                       pid,
 537                                       ci));
 538     return;
 539   }
 540   if (NULL == ci)
 541   {
 542     ci = GNUNET_new (struct ConnectInfo);
 543     GNUNET_assert (GNUNET_OK ==
 544                    GNUNET_CONTAINER_multipeermap_put (all_desired_peers,
 545                                                       pid,
 546                                                       ci,
 547                                                       GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
 548   }
 549   if ( (NULL != ci->oh) &&
 550        (NULL != h) )
 551     GNUNET_TRANSPORT_offer_hello_cancel (ci->oh);
 552   if (NULL != h)
 553     ci->oh = GNUNET_TRANSPORT_offer_hello (GDS_cfg,
 554                                            h,
 555                                            &offer_hello_done,
 556                                            ci);
 557   if ( (NULL != ci->sh) &&
 558        (ci->strength != strength) )
 559     GNUNET_ATS_connectivity_suggest_cancel (ci->sh);
 560   if (ci->strength != strength)
 561     ci->sh = GNUNET_ATS_connectivity_suggest (ats_ch,
 562                                               pid,
 563                                               strength);
 564   ci->strength = strength;
 565 }
 566
 567
 568 /**
 569  * Function called for each peer in #all_desired_peers during
 570  * #update_connect_preferences() if we have reason to adjust
 571  * the strength of our desire to keep connections to certain
 572  * peers.  Calls #try_connect() to update the calculations for
 573  * the given @a pid.
 574  *
 575  * @param cls NULL
 576  * @param pid peer to update
 577  * @param value unused
 578  * @return #GNUNET_YES (continue to iterate)
 579  */
 580 static int
 581 update_desire_strength (void *cls,
 582                         const struct GNUNET_PeerIdentity *pid,
 583                         void *value)
 584 {
 585   (void) cls;
 586   (void) value;
 587   try_connect (pid,
 588                NULL);
 589   return GNUNET_YES;
 590 }
 591
 592
 593 /**
 594  * Update our preferences for connectivity as given to ATS.
 595  *
 596  * @param cls the `struct PeerInfo` of the peer
 597  * @param tc scheduler context.
 598  */
 599 static void
 600 update_connect_preferences ()
 601 {
 602   GNUNET_CONTAINER_multipeermap_iterate (all_desired_peers,
 603                                          &update_desire_strength,
 604                                          NULL);
 605 }
 606
 607
 608 /**
 609  * Add each of the peers we already know to the bloom filter of
 610  * the request so that we don't get duplicate HELLOs.
 611  *
 612  * @param cls the `struct GNUNET_BLOCK_Group`
 613  * @param key peer identity to add to the bloom filter
 614  * @param value value the peer information (unused)
 615  * @return #GNUNET_YES (we should continue to iterate)
 616  */
 617 static int
 618 add_known_to_bloom (void *cls,
 619                     const struct GNUNET_PeerIdentity *key,
 620                     void *value)
 621 {
 622   struct GNUNET_BLOCK_Group *bg = cls;
 623   struct GNUNET_HashCode key_hash;
 624
 625  (void) cls;
 626  (void) value;
 627   GNUNET_CRYPTO_hash (key,
 628                       sizeof (struct GNUNET_PeerIdentity),
 629                       &key_hash);
 630   GNUNET_BLOCK_group_set_seen (bg,
 631                                &key_hash,
 632                                1);
 633   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 634               "Adding known peer (%s) to bloomfilter for FIND PEER\n",
 635               GNUNET_i2s (key));
 636   return GNUNET_YES;
 637 }
 638
 639
 640 /**
 641  * Task to send a find peer message for our own peer identifier
 642  * so that we can find the closest peers in the network to ourselves
 643  * and attempt to connect to them.
 644  *
 645  * @param cls closure for this task
 646  */
 647 static void
 648 send_find_peer_message (void *cls)
 649 {
 650   struct GNUNET_TIME_Relative next_send_time;
 651   struct GNUNET_BLOCK_Group *bg;
 652   struct GNUNET_CONTAINER_BloomFilter *peer_bf;
 653
 654  (void) cls;
 655  find_peer_task = NULL;
 656   if (newly_found_peers > bucket_size)
 657   {
 658     /* If we are finding many peers already, no need to send out our request right now! */
 659     find_peer_task =
 660         GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_MINUTES,
 661                                       &send_find_peer_message,
 662                                       NULL);
 663     newly_found_peers = 0;
 664     return;
 665   }
 666   bg = GNUNET_BLOCK_group_create (GDS_block_context,
 667                                   GNUNET_BLOCK_TYPE_DHT_HELLO,
 668                                   GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK,
 669                                                             UINT32_MAX),
 670                                   NULL,
 671                                   0,
 672                                   "filter-size",
 673                                   DHT_BLOOM_SIZE,
 674                                   NULL);
 675   GNUNET_CONTAINER_multipeermap_iterate (all_connected_peers,
 676                                          &add_known_to_bloom,
 677                                          bg);
 678   GNUNET_STATISTICS_update (GDS_stats,
 679                             gettext_noop ("# FIND PEER messages initiated"),
 680                             1,
 681                             GNUNET_NO);
 682   peer_bf
 683     = GNUNET_CONTAINER_bloomfilter_init (NULL,
 684                                          DHT_BLOOM_SIZE,
 685                                          GNUNET_CONSTANTS_BLOOMFILTER_K);
 686   // FIXME: pass priority!?
 687   GDS_NEIGHBOURS_handle_get (GNUNET_BLOCK_TYPE_DHT_HELLO,
 688                              GNUNET_DHT_RO_FIND_PEER | GNUNET_DHT_RO_RECORD_ROUTE,
 689                              FIND_PEER_REPLICATION_LEVEL,
 690                              0,
 691                              &my_identity_hash,
 692                              NULL,
 693                              0,
 694                              bg,
 695                              peer_bf);
 696   GNUNET_CONTAINER_bloomfilter_free (peer_bf);
 697   GNUNET_BLOCK_group_destroy (bg);
 698   /* schedule next round */
 699   next_send_time.rel_value_us =
 700       DHT_MINIMUM_FIND_PEER_INTERVAL.rel_value_us +
 701       GNUNET_CRYPTO_random_u64 (GNUNET_CRYPTO_QUALITY_WEAK,
 702                                 DHT_MAXIMUM_FIND_PEER_INTERVAL.rel_value_us /
 703                                 (newly_found_peers + 1));
 704   newly_found_peers = 0;
 705   GNUNET_assert (NULL == find_peer_task);
 706   find_peer_task =
 707       GNUNET_SCHEDULER_add_delayed (next_send_time,
 708                                     &send_find_peer_message,
 709                                     NULL);
 710 }
 711
 712
 713 /**
 714  * Method called whenever a peer connects.
 715  *
 716  * @param cls closure
 717  * @param peer peer identity this notification is about
 718  * @param mq message queue for sending messages to @a peer
 719  * @return our `struct PeerInfo` for @a peer
 720  */
 721 static void *
 722 handle_core_connect (void *cls,
 723                      const struct GNUNET_PeerIdentity *peer,
 724                      struct GNUNET_MQ_Handle *mq)
 725 {
 726   struct PeerInfo *pi;
 727
 728  (void) cls;
 729  /* Check for connect to self message */
 730   if (0 == GNUNET_memcmp (&my_identity,
 731                    peer))
 732     return NULL;
 733   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 734               "Connected to %s\n",
 735               GNUNET_i2s (peer));
 736   GNUNET_assert (GNUNET_NO ==
 737                  GNUNET_CONTAINER_multipeermap_get (all_connected_peers,
 738                                                     peer));
 739   GNUNET_STATISTICS_update (GDS_stats,
 740                             gettext_noop ("# peers connected"),
 741                             1,
 742                             GNUNET_NO);
 743   pi = GNUNET_new (struct PeerInfo);
 744   pi->id = peer;
 745   pi->mq = mq;
 746   GNUNET_CRYPTO_hash (peer,
 747                       sizeof (struct GNUNET_PeerIdentity),
 748                       &pi->phash);
 749   pi->peer_bucket = find_bucket (&pi->phash);
 750   GNUNET_assert ( (pi->peer_bucket >= 0) &&
 751                   ((unsigned int) pi->peer_bucket < MAX_BUCKETS) );
 752   GNUNET_CONTAINER_DLL_insert_tail (k_buckets[pi->peer_bucket].head,
 753                                     k_buckets[pi->peer_bucket].tail,
 754                                     pi);
 755   k_buckets[pi->peer_bucket].peers_size++;
 756   closest_bucket = GNUNET_MAX (closest_bucket,
 757                                (unsigned int) pi->peer_bucket);
 758   GNUNET_assert (GNUNET_OK ==
 759                  GNUNET_CONTAINER_multipeermap_put (all_connected_peers,
 760                                                     pi->id,
 761                                                     pi,
 762                                                     GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
 763   if ( (pi->peer_bucket > 0) &&
 764        (k_buckets[pi->peer_bucket].peers_size <= bucket_size))
 765   {
 766     update_connect_preferences ();
 767     newly_found_peers++;
 768   }
 769   if ( (1 == GNUNET_CONTAINER_multipeermap_size (all_connected_peers)) &&
 770        (GNUNET_YES != disable_try_connect))
 771   {
 772     /* got a first connection, good time to start with FIND PEER requests... */
 773     GNUNET_assert (NULL == find_peer_task);
 774     find_peer_task = GNUNET_SCHEDULER_add_now (&send_find_peer_message,
 775                                                NULL);
 776   }
 777   return pi;
 778 }
 779
 780
 781 /**
 782  * Method called whenever a peer disconnects.
 783  *
 784  * @param cls closure
 785  * @param peer peer identity this notification is about
 786  * @param internal_cls our `struct PeerInfo` for @a peer
 787  */
 788 static void
 789 handle_core_disconnect (void *cls,
 790                         const struct GNUNET_PeerIdentity *peer,
 791                         void *internal_cls)
 792 {
 793   struct PeerInfo *to_remove = internal_cls;
 794
 795   (void) cls;
 796   /* Check for disconnect from self message */
 797   if (NULL == to_remove)
 798     return;
 799   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 800               "Disconnected %s\n",
 801               GNUNET_i2s (peer));
 802   GNUNET_STATISTICS_update (GDS_stats,
 803                             gettext_noop ("# peers connected"),
 804                             -1,
 805                             GNUNET_NO);
 806   GNUNET_assert (GNUNET_YES ==
 807                  GNUNET_CONTAINER_multipeermap_remove (all_connected_peers,
 808                                                        peer,
 809                                                        to_remove));
 810   if ( (0 == GNUNET_CONTAINER_multipeermap_size (all_connected_peers)) &&
 811        (GNUNET_YES != disable_try_connect) )
 812   {
 813     GNUNET_SCHEDULER_cancel (find_peer_task);
 814     find_peer_task = NULL;
 815   }
 816   GNUNET_assert (to_remove->peer_bucket >= 0);
 817   GNUNET_CONTAINER_DLL_remove (k_buckets[to_remove->peer_bucket].head,
 818                                k_buckets[to_remove->peer_bucket].tail,
 819                                to_remove);
 820   GNUNET_assert (k_buckets[to_remove->peer_bucket].peers_size > 0);
 821   k_buckets[to_remove->peer_bucket].peers_size--;
 822   while ( (closest_bucket > 0) &&
 823           (0 == k_buckets[to_remove->peer_bucket].peers_size) )
 824     closest_bucket--;
 825   if (k_buckets[to_remove->peer_bucket].peers_size < bucket_size)
 826     update_connect_preferences ();
 827   GNUNET_free (to_remove);
 828 }
 829
 830
 831 /**
 832  * To how many peers should we (on average) forward the request to
 833  * obtain the desired target_replication count (on average).
 834  *
 835  * @param hop_count number of hops the message has traversed
 836  * @param target_replication the number of total paths desired
 837  * @return Some number of peers to forward the message to
 838  */
 839 static unsigned int
 840 get_forward_count (uint32_t hop_count,
 841                    uint32_t target_replication)
 842 {
 843   uint32_t random_value;
 844   uint32_t forward_count;
 845   float target_value;
 846
 847   if (hop_count > GDS_NSE_get () * 4.0)
 848   {
 849     /* forcefully terminate */
 850     GNUNET_STATISTICS_update (GDS_stats,
 851                               gettext_noop ("# requests TTL-dropped"),
 852                               1, GNUNET_NO);
 853     return 0;
 854   }
 855   if (hop_count > GDS_NSE_get () * 2.0)
 856   {
 857     /* Once we have reached our ideal number of hops, only forward to 1 peer */
 858     return 1;
 859   }
 860   /* bound by system-wide maximum */
 861   target_replication =
 862       GNUNET_MIN (MAXIMUM_REPLICATION_LEVEL, target_replication);
 863   target_value =
 864       1 + (target_replication - 1.0) / (GDS_NSE_get () +
 865                                         ((float) (target_replication - 1.0) *
 866                                          hop_count));
 867   /* Set forward count to floor of target_value */
 868   forward_count = (uint32_t) target_value;
 869   /* Subtract forward_count (floor) from target_value (yields value between 0 and 1) */
 870   target_value = target_value - forward_count;
 871   random_value =
 872       GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK, UINT32_MAX);
 873   if (random_value < (target_value * UINT32_MAX))
 874     forward_count++;
 875   return forward_count;
 876 }
 877
 878
 879 /**
 880  * Compute the distance between have and target as a 32-bit value.
 881  * Differences in the lower bits must count stronger than differences
 882  * in the higher bits.
 883  *
 884  * @param target
 885  * @param have
 886  * @return 0 if have==target, otherwise a number
 887  *           that is larger as the distance between
 888  *           the two hash codes increases
 889  */
 890 static unsigned int
 891 get_distance (const struct GNUNET_HashCode *target,
 892               const struct GNUNET_HashCode *have)
 893 {
 894   unsigned int bucket;
 895   unsigned int msb;
 896   unsigned int lsb;
 897   unsigned int i;
 898
 899   /* We have to represent the distance between two 2^9 (=512)-bit
 900    * numbers as a 2^5 (=32)-bit number with "0" being used for the
 901    * two numbers being identical; furthermore, we need to
 902    * guarantee that a difference in the number of matching
 903    * bits is always represented in the result.
 904    *
 905    * We use 2^32/2^9 numerical values to distinguish between
 906    * hash codes that have the same LSB bit distance and
 907    * use the highest 2^9 bits of the result to signify the
 908    * number of (mis)matching LSB bits; if we have 0 matching
 909    * and hence 512 mismatching LSB bits we return -1 (since
 910    * 512 itself cannot be represented with 9 bits) */
 911
 912   /* first, calculate the most significant 9 bits of our
 913    * result, aka the number of LSBs */
 914   bucket = GNUNET_CRYPTO_hash_matching_bits (target,
 915                                              have);
 916   /* bucket is now a value between 0 and 512 */
 917   if (bucket == 512)
 918     return 0;                   /* perfect match */
 919   if (bucket == 0)
 920     return (unsigned int) -1;   /* LSB differs; use max (if we did the bit-shifting
 921                                  * below, we'd end up with max+1 (overflow)) */
 922
 923   /* calculate the most significant bits of the final result */
 924   msb = (512 - bucket) << (32 - 9);
 925   /* calculate the 32-9 least significant bits of the final result by
 926    * looking at the differences in the 32-9 bits following the
 927    * mismatching bit at 'bucket' */
 928   lsb = 0;
 929   for (i = bucket + 1;
 930        (i < sizeof (struct GNUNET_HashCode) * 8) && (i < bucket + 1 + 32 - 9); i++)
 931   {
 932     if (GNUNET_CRYPTO_hash_get_bit (target, i) !=
 933         GNUNET_CRYPTO_hash_get_bit (have, i))
 934       lsb |= (1 << (bucket + 32 - 9 - i));      /* first bit set will be 10,
 935                                                  * last bit set will be 31 -- if
 936                                                  * i does not reach 512 first... */
 937   }
 938   return msb | lsb;
 939 }
 940
 941
 942 /**
 943  * Check whether my identity is closer than any known peers.  If a
 944  * non-null bloomfilter is given, check if this is the closest peer
 945  * that hasn't already been routed to.
 946  *
 947  * @param key hash code to check closeness to
 948  * @param bloom bloomfilter, exclude these entries from the decision
 949  * @return #GNUNET_YES if node location is closest,
 950  *         #GNUNET_NO otherwise.
 951  */
 952 int
 953 GDS_am_closest_peer (const struct GNUNET_HashCode *key,
 954                      const struct GNUNET_CONTAINER_BloomFilter *bloom)
 955 {
 956   int bits;
 957   int other_bits;
 958   int bucket_num;
 959   struct PeerInfo *pos;
 960
 961   if (0 == GNUNET_memcmp (&my_identity_hash,
 962                    key))
 963     return GNUNET_YES;
 964   bucket_num = find_bucket (key);
 965   GNUNET_assert (bucket_num >= 0);
 966   bits = GNUNET_CRYPTO_hash_matching_bits (&my_identity_hash,
 967                                            key);
 968   pos = k_buckets[bucket_num].head;
 969   while (NULL != pos)
 970   {
 971     if ( (NULL != bloom) &&
 972          (GNUNET_YES ==
 973           GNUNET_CONTAINER_bloomfilter_test (bloom,
 974                                              &pos->phash)) )
 975     {
 976       pos = pos->next;
 977       continue;                 /* Skip already checked entries */
 978     }
 979     other_bits = GNUNET_CRYPTO_hash_matching_bits (&pos->phash,
 980                                                    key);
 981     if (other_bits > bits)
 982       return GNUNET_NO;
 983     if (other_bits == bits)     /* We match the same number of bits */
 984       return GNUNET_YES;
 985     pos = pos->next;
 986   }
 987   /* No peers closer, we are the closest! */
 988   return GNUNET_YES;
 989 }
 990
 991
 992 /**
 993  * Select a peer from the routing table that would be a good routing
 994  * destination for sending a message for "key".  The resulting peer
 995  * must not be in the set of blocked peers.<p>
 996  *
 997  * Note that we should not ALWAYS select the closest peer to the
 998  * target, peers further away from the target should be chosen with
 999  * exponentially declining probability.
1000  *
1001  * FIXME: double-check that this is fine
1002  *
1003  *
1004  * @param key the key we are selecting a peer to route to
1005  * @param bloom a bloomfilter containing entries this request has seen already
1006  * @param hops how many hops has this message traversed thus far
1007  * @return Peer to route to, or NULL on error
1008  */
1009 static struct PeerInfo *
1010 select_peer (const struct GNUNET_HashCode *key,
1011              const struct GNUNET_CONTAINER_BloomFilter *bloom,
1012              uint32_t hops)
1013 {
1014   unsigned int bc;
1015   unsigned int count;
1016   unsigned int selected;
1017   struct PeerInfo *pos;
1018   unsigned int dist;
1019   unsigned int smallest_distance;
1020   struct PeerInfo *chosen;
1021
1022   if (hops >= GDS_NSE_get ())
1023   {
1024     /* greedy selection (closest peer that is not in bloomfilter) */
1025     smallest_distance = UINT_MAX;
1026     chosen = NULL;
1027     for (bc = 0; bc <= closest_bucket; bc++)
1028     {
1029       pos = k_buckets[bc].head;
1030       count = 0;
1031       while ((pos != NULL) && (count < bucket_size))
1032       {
1033         if ( (NULL == bloom) ||
1034              (GNUNET_NO ==
1035               GNUNET_CONTAINER_bloomfilter_test (bloom,
1036                                                  &pos->phash)))
1037         {
1038           dist = get_distance (key,
1039                                &pos->phash);
1040           if (dist < smallest_distance)
1041           {
1042             chosen = pos;
1043             smallest_distance = dist;
1044           }
1045         }
1046         else
1047         {
1048           GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1049                       "Excluded peer `%s' due to BF match in greedy routing for %s\n",
1050                       GNUNET_i2s (pos->id),
1051                       GNUNET_h2s (key));
1052           GNUNET_STATISTICS_update (GDS_stats,
1053                                     gettext_noop ("# Peers excluded from routing due to Bloomfilter"),
1054                                     1,
1055                                     GNUNET_NO);
1056           dist = get_distance (key,
1057                                &pos->phash);
1058           if (dist < smallest_distance)
1059           {
1060             chosen = NULL;
1061             smallest_distance = dist;
1062           }
1063         }
1064         count++;
1065         pos = pos->next;
1066       }
1067     }
1068     if (NULL == chosen)
1069       GNUNET_STATISTICS_update (GDS_stats,
1070                                 gettext_noop ("# Peer selection failed"),
1071                                 1,
1072                                 GNUNET_NO);
1073     else
1074       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1075                   "Selected peer `%s' in greedy routing for %s\n",
1076                   GNUNET_i2s (chosen->id),
1077                   GNUNET_h2s (key));
1078     return chosen;
1079   }
1080
1081   /* select "random" peer */
1082   /* count number of peers that are available and not filtered */
1083   count = 0;
1084   for (bc = 0; bc <= closest_bucket; bc++)
1085   {
1086     pos = k_buckets[bc].head;
1087     while ( (NULL != pos) && (count < bucket_size) )
1088     {
1089       if ( (NULL != bloom) &&
1090            (GNUNET_YES ==
1091             GNUNET_CONTAINER_bloomfilter_test (bloom,
1092                                                &pos->phash)) )
1093       {
1094         GNUNET_STATISTICS_update (GDS_stats,
1095                                   gettext_noop
1096                                   ("# Peers excluded from routing due to Bloomfilter"),
1097                                   1, GNUNET_NO);
1098         GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1099                     "Excluded peer `%s' due to BF match in random routing for %s\n",
1100                     GNUNET_i2s (pos->id),
1101                     GNUNET_h2s (key));
1102         pos = pos->next;
1103         continue;               /* Ignore bloomfiltered peers */
1104       }
1105       count++;
1106       pos = pos->next;
1107     }
1108   }
1109   if (0 == count)               /* No peers to select from! */
1110   {
1111     GNUNET_STATISTICS_update (GDS_stats,
1112                               gettext_noop ("# Peer selection failed"), 1,
1113                               GNUNET_NO);
1114     return NULL;
1115   }
1116   /* Now actually choose a peer */
1117   selected = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK,
1118                                        count);
1119   count = 0;
1120   for (bc = 0; bc <= closest_bucket; bc++)
1121   {
1122     for (pos = k_buckets[bc].head; ((pos != NULL) && (count < bucket_size)); pos = pos->next)
1123     {
1124       if ((bloom != NULL) &&
1125           (GNUNET_YES ==
1126            GNUNET_CONTAINER_bloomfilter_test (bloom,
1127                                               &pos->phash)))
1128       {
1129         continue;               /* Ignore bloomfiltered peers */
1130       }
1131       if (0 == selected--)
1132       {
1133         GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1134                     "Selected peer `%s' in random routing for %s\n",
1135                     GNUNET_i2s (pos->id),
1136                     GNUNET_h2s (key));
1137         return pos;
1138       }
1139     }
1140   }
1141   GNUNET_break (0);
1142   return NULL;
1143 }
1144
1145
1146 /**
1147  * Compute the set of peers that the given request should be
1148  * forwarded to.
1149  *
1150  * @param key routing key
1151  * @param bloom bloom filter excluding peers as targets, all selected
1152  *        peers will be added to the bloom filter
1153  * @param hop_count number of hops the request has traversed so far
1154  * @param target_replication desired number of replicas
1155  * @param targets where to store an array of target peers (to be
1156  *         free'd by the caller)
1157  * @return number of peers returned in 'targets'.
1158  */
1159 static unsigned int
1160 get_target_peers (const struct GNUNET_HashCode *key,
1161                   struct GNUNET_CONTAINER_BloomFilter *bloom,
1162                   uint32_t hop_count,
1163                   uint32_t target_replication,
1164                   struct PeerInfo ***targets)
1165 {
1166   unsigned int ret;
1167   unsigned int off;
1168   struct PeerInfo **rtargets;
1169   struct PeerInfo *nxt;
1170
1171   GNUNET_assert (NULL != bloom);
1172   ret = get_forward_count (hop_count,
1173                            target_replication);
1174   if (0 == ret)
1175   {
1176     *targets = NULL;
1177     return 0;
1178   }
1179   rtargets = GNUNET_new_array (ret,
1180                                struct PeerInfo *);
1181   for (off = 0; off < ret; off++)
1182   {
1183     nxt = select_peer (key,
1184                        bloom,
1185                        hop_count);
1186     if (NULL == nxt)
1187       break;
1188     rtargets[off] = nxt;
1189     GNUNET_break (GNUNET_NO ==
1190                   GNUNET_CONTAINER_bloomfilter_test (bloom,
1191                                                      &nxt->phash));
1192     GNUNET_CONTAINER_bloomfilter_add (bloom,
1193                                       &nxt->phash);
1194   }
1195   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1196               "Selected %u/%u peers at hop %u for %s (target was %u)\n",
1197               off,
1198               GNUNET_CONTAINER_multipeermap_size (all_connected_peers),
1199               (unsigned int) hop_count,
1200               GNUNET_h2s (key),
1201               ret);
1202   if (0 == off)
1203   {
1204     GNUNET_free (rtargets);
1205     *targets = NULL;
1206     return 0;
1207   }
1208   *targets = rtargets;
1209   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1210               "Forwarding query `%s' to %u peers (goal was %u peers)\n",
1211               GNUNET_h2s (key),
1212               off,
1213               ret);
1214   return off;
1215 }
1216
1217
1218 /**
1219  * Perform a PUT operation.   Forwards the given request to other
1220  * peers.   Does not store the data locally.  Does not give the
1221  * data to local clients.  May do nothing if this is the only
1222  * peer in the network (or if we are the closest peer in the
1223  * network).
1224  *
1225  * @param type type of the block
1226  * @param options routing options
1227  * @param desired_replication_level desired replication count
1228  * @param expiration_time when does the content expire
1229  * @param hop_count how many hops has this message traversed so far
1230  * @param bf Bloom filter of peers this PUT has already traversed
1231  * @param key key for the content
1232  * @param put_path_length number of entries in @a put_path
1233  * @param put_path peers this request has traversed so far (if tracked)
1234  * @param data payload to store
1235  * @param data_size number of bytes in @a data
1236  * @return #GNUNET_OK if the request was forwarded, #GNUNET_NO if not
1237  */
1238 int
1239 GDS_NEIGHBOURS_handle_put (enum GNUNET_BLOCK_Type type,
1240                            enum GNUNET_DHT_RouteOption options,
1241                            uint32_t desired_replication_level,
1242                            struct GNUNET_TIME_Absolute expiration_time,
1243                            uint32_t hop_count,
1244                            struct GNUNET_CONTAINER_BloomFilter *bf,
1245                            const struct GNUNET_HashCode *key,
1246                            unsigned int put_path_length,
1247                            struct GNUNET_PeerIdentity *put_path,
1248                            const void *data,
1249                            size_t data_size)
1250 {
1251   unsigned int target_count;
1252   unsigned int i;
1253   struct PeerInfo **targets;
1254   struct PeerInfo *target;
1255   size_t msize;
1256   struct GNUNET_MQ_Envelope *env;
1257   struct PeerPutMessage *ppm;
1258   struct GNUNET_PeerIdentity *pp;
1259   unsigned int skip_count;
1260
1261   GNUNET_assert (NULL != bf);
1262   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1263               "Adding myself (%s) to PUT bloomfilter for %s\n",
1264               GNUNET_i2s (&my_identity),
1265               GNUNET_h2s (key));
1266   GNUNET_CONTAINER_bloomfilter_add (bf,
1267                                     &my_identity_hash);
1268   GNUNET_STATISTICS_update (GDS_stats,
1269                             gettext_noop ("# PUT requests routed"),
1270                             1,
1271                             GNUNET_NO);
1272   target_count
1273     = get_target_peers (key,
1274                         bf,
1275                         hop_count,
1276                         desired_replication_level,
1277                         &targets);
1278   if (0 == target_count)
1279   {
1280     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1281                 "Routing PUT for %s terminates after %u hops at %s\n",
1282                 GNUNET_h2s (key),
1283                 (unsigned int) hop_count,
1284                 GNUNET_i2s (&my_identity));
1285     return GNUNET_NO;
1286   }
1287   msize = put_path_length * sizeof (struct GNUNET_PeerIdentity) + data_size;
1288   if (msize + sizeof (struct PeerPutMessage)
1289       >= GNUNET_CONSTANTS_MAX_ENCRYPTED_MESSAGE_SIZE)
1290   {
1291     put_path_length = 0;
1292     msize = data_size;
1293   }
1294   if (msize + sizeof (struct PeerPutMessage)
1295       >= GNUNET_CONSTANTS_MAX_ENCRYPTED_MESSAGE_SIZE)
1296   {
1297     GNUNET_break (0);
1298     GNUNET_free (targets);
1299     return GNUNET_NO;
1300   }
1301   GNUNET_STATISTICS_update (GDS_stats,
1302                             gettext_noop ("# PUT messages queued for transmission"),
1303                             target_count,
1304                             GNUNET_NO);
1305   skip_count = 0;
1306   for (i = 0; i < target_count; i++)
1307   {
1308     target = targets[i];
1309     if (GNUNET_MQ_get_length (target->mq) >= MAXIMUM_PENDING_PER_PEER)
1310     {
1311       /* skip */
1312       GNUNET_STATISTICS_update (GDS_stats,
1313                                 gettext_noop ("# P2P messages dropped due to full queue"),
1314                                 1,
1315                                 GNUNET_NO);
1316       skip_count++;
1317       continue;
1318     }
1319     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1320                 "Routing PUT for %s after %u hops to %s\n",
1321                 GNUNET_h2s (key),
1322                 (unsigned int) hop_count,
1323                 GNUNET_i2s (target->id));
1324     env = GNUNET_MQ_msg_extra (ppm,
1325                                msize,
1326                                GNUNET_MESSAGE_TYPE_DHT_P2P_PUT);
1327     ppm->options = htonl (options);
1328     ppm->type = htonl (type);
1329     ppm->hop_count = htonl (hop_count + 1);
1330     ppm->desired_replication_level = htonl (desired_replication_level);
1331     ppm->put_path_length = htonl (put_path_length);
1332     ppm->expiration_time = GNUNET_TIME_absolute_hton (expiration_time);
1333     GNUNET_break (GNUNET_YES ==
1334                   GNUNET_CONTAINER_bloomfilter_test (bf,
1335                                                      &target->phash));
1336     GNUNET_assert (GNUNET_OK ==
1337                    GNUNET_CONTAINER_bloomfilter_get_raw_data (bf,
1338                                                               ppm->bloomfilter,
1339                                                               DHT_BLOOM_SIZE));
1340     ppm->key = *key;
1341     pp = (struct GNUNET_PeerIdentity *) &ppm[1];
1342     GNUNET_memcpy (pp,
1343                    put_path,
1344                    sizeof (struct GNUNET_PeerIdentity) * put_path_length);
1345     GNUNET_memcpy (&pp[put_path_length],
1346                    data,
1347                    data_size);
1348     GNUNET_MQ_send (target->mq,
1349                     env);
1350   }
1351   GNUNET_free (targets);
1352   return (skip_count < target_count) ? GNUNET_OK : GNUNET_NO;
1353 }
1354
1355
1356 /**
1357  * Perform a GET operation.  Forwards the given request to other
1358  * peers.  Does not lookup the key locally.  May do nothing if this is
1359  * the only peer in the network (or if we are the closest peer in the
1360  * network).
1361  *
1362  * @param type type of the block
1363  * @param options routing options
1364  * @param desired_replication_level desired replication count
1365  * @param hop_count how many hops did this request traverse so far?
1366  * @param key key for the content
1367  * @param xquery extended query
1368  * @param xquery_size number of bytes in @a xquery
1369  * @param bg group to use for filtering replies
1370  * @param peer_bf filter for peers not to select (again)
1371  * @return #GNUNET_OK if the request was forwarded, #GNUNET_NO if not
1372  */
1373 int
1374 GDS_NEIGHBOURS_handle_get (enum GNUNET_BLOCK_Type type,
1375                            enum GNUNET_DHT_RouteOption options,
1376                            uint32_t desired_replication_level,
1377                            uint32_t hop_count,
1378                            const struct GNUNET_HashCode *key,
1379                            const void *xquery,
1380                            size_t xquery_size,
1381                            struct GNUNET_BLOCK_Group *bg,
1382                            struct GNUNET_CONTAINER_BloomFilter *peer_bf)
1383 {
1384   unsigned int target_count;
1385   struct PeerInfo **targets;
1386   struct PeerInfo *target;
1387   struct GNUNET_MQ_Envelope *env;
1388   size_t msize;
1389   struct PeerGetMessage *pgm;
1390   char *xq;
1391   size_t reply_bf_size;
1392   void *reply_bf;
1393   unsigned int skip_count;
1394   uint32_t bf_nonce;
1395
1396   GNUNET_assert (NULL != peer_bf);
1397   GNUNET_STATISTICS_update (GDS_stats,
1398                             gettext_noop ("# GET requests routed"),
1399                             1,
1400                             GNUNET_NO);
1401   target_count = get_target_peers (key,
1402                                    peer_bf,
1403                                    hop_count,
1404                                    desired_replication_level,
1405                                    &targets);
1406   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1407               "Adding myself (%s) to GET bloomfilter for %s\n",
1408               GNUNET_i2s (&my_identity),
1409               GNUNET_h2s (key));
1410   GNUNET_CONTAINER_bloomfilter_add (peer_bf,
1411                                     &my_identity_hash);
1412   if (0 == target_count)
1413   {
1414     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1415                 "Routing GET for %s terminates after %u hops at %s\n",
1416                 GNUNET_h2s (key),
1417                 (unsigned int) hop_count,
1418                 GNUNET_i2s (&my_identity));
1419     return GNUNET_NO;
1420   }
1421   if (GNUNET_OK !=
1422       GNUNET_BLOCK_group_serialize (bg,
1423                                     &bf_nonce,
1424                                     &reply_bf,
1425                                     &reply_bf_size))
1426   {
1427     reply_bf = NULL;
1428     reply_bf_size = 0;
1429     bf_nonce = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK,
1430                                          UINT32_MAX);
1431   }
1432   msize = xquery_size + reply_bf_size;
1433   if (msize + sizeof (struct PeerGetMessage) >= GNUNET_MAX_MESSAGE_SIZE)
1434   {
1435     GNUNET_break (0);
1436     GNUNET_free_non_null (reply_bf);
1437     GNUNET_free (targets);
1438     return GNUNET_NO;
1439   }
1440   GNUNET_STATISTICS_update (GDS_stats,
1441                             gettext_noop ("# GET messages queued for transmission"),
1442                             target_count,
1443                             GNUNET_NO);
1444   /* forward request */
1445   skip_count = 0;
1446   for (unsigned int i = 0; i < target_count; i++)
1447   {
1448     target = targets[i];
1449     if (GNUNET_MQ_get_length (target->mq) >= MAXIMUM_PENDING_PER_PEER)
1450     {
1451       /* skip */
1452       GNUNET_STATISTICS_update (GDS_stats,
1453                                 gettext_noop ("# P2P messages dropped due to full queue"),
1454                                 1, GNUNET_NO);
1455       skip_count++;
1456       continue;
1457     }
1458     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1459                 "Routing GET for %s after %u hops to %s\n",
1460                 GNUNET_h2s (key),
1461                 (unsigned int) hop_count,
1462                 GNUNET_i2s (target->id));
1463     env = GNUNET_MQ_msg_extra (pgm,
1464                                msize,
1465                                GNUNET_MESSAGE_TYPE_DHT_P2P_GET);
1466     pgm->options = htonl (options);
1467     pgm->type = htonl (type);
1468     pgm->hop_count = htonl (hop_count + 1);
1469     pgm->desired_replication_level = htonl (desired_replication_level);
1470     pgm->xquery_size = htonl (xquery_size);
1471     pgm->bf_mutator = bf_nonce;
1472     GNUNET_break (GNUNET_YES ==
1473                   GNUNET_CONTAINER_bloomfilter_test (peer_bf,
1474                                                      &target->phash));
1475     GNUNET_assert (GNUNET_OK ==
1476                    GNUNET_CONTAINER_bloomfilter_get_raw_data (peer_bf,
1477                                                               pgm->bloomfilter,
1478                                                               DHT_BLOOM_SIZE));
1479     pgm->key = *key;
1480     xq = (char *) &pgm[1];
1481     GNUNET_memcpy (xq,
1482                    xquery,
1483                    xquery_size);
1484     GNUNET_memcpy (&xq[xquery_size],
1485                    reply_bf,
1486                    reply_bf_size);
1487     GNUNET_MQ_send (target->mq,
1488                     env);
1489   }
1490   GNUNET_free (targets);
1491   GNUNET_free_non_null (reply_bf);
1492   return (skip_count < target_count) ? GNUNET_OK : GNUNET_NO;
1493 }
1494
1495
1496 /**
1497  * Handle a reply (route to origin).  Only forwards the reply back to
1498  * the given peer.  Does not do local caching or forwarding to local
1499  * clients.
1500  *
1501  * @param target neighbour that should receive the block (if still connected)
1502  * @param type type of the block
1503  * @param expiration_time when does the content expire
1504  * @param key key for the content
1505  * @param put_path_length number of entries in @a put_path
1506  * @param put_path peers the original PUT traversed (if tracked)
1507  * @param get_path_length number of entries in @a get_path
1508  * @param get_path peers this reply has traversed so far (if tracked)
1509  * @param data payload of the reply
1510  * @param data_size number of bytes in @a data
1511  */
1512 void
1513 GDS_NEIGHBOURS_handle_reply (const struct GNUNET_PeerIdentity *target,
1514                              enum GNUNET_BLOCK_Type type,
1515                              struct GNUNET_TIME_Absolute expiration_time,
1516                              const struct GNUNET_HashCode *key,
1517                              unsigned int put_path_length,
1518                              const struct GNUNET_PeerIdentity *put_path,
1519                              unsigned int get_path_length,
1520                              const struct GNUNET_PeerIdentity *get_path,
1521                              const void *data,
1522                              size_t data_size)
1523 {
1524   struct PeerInfo *pi;
1525   struct GNUNET_MQ_Envelope *env;
1526   size_t msize;
1527   struct PeerResultMessage *prm;
1528   struct GNUNET_PeerIdentity *paths;
1529
1530   msize = data_size + (get_path_length + put_path_length) *
1531       sizeof (struct GNUNET_PeerIdentity);
1532   if ((msize + sizeof (struct PeerResultMessage) >= GNUNET_MAX_MESSAGE_SIZE) ||
1533       (get_path_length >
1534        GNUNET_MAX_MESSAGE_SIZE / sizeof (struct GNUNET_PeerIdentity)) ||
1535       (put_path_length >
1536        GNUNET_MAX_MESSAGE_SIZE / sizeof (struct GNUNET_PeerIdentity)) ||
1537       (data_size > GNUNET_MAX_MESSAGE_SIZE))
1538   {
1539     GNUNET_break (0);
1540     return;
1541   }
1542   pi = GNUNET_CONTAINER_multipeermap_get (all_connected_peers,
1543                                           target);
1544   if (NULL == pi)
1545   {
1546     /* peer disconnected in the meantime, drop reply */
1547     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1548                 "No matching peer for reply for key %s\n",
1549                 GNUNET_h2s (key));
1550     return;
1551   }
1552   if (GNUNET_MQ_get_length (pi->mq) >= MAXIMUM_PENDING_PER_PEER)
1553   {
1554     /* skip */
1555     GNUNET_STATISTICS_update (GDS_stats,
1556                               gettext_noop ("# P2P messages dropped due to full queue"),
1557                               1,
1558                               GNUNET_NO);
1559     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1560                 "Peer queue full, ignoring reply for key %s\n",
1561                 GNUNET_h2s (key));
1562     return;
1563   }
1564
1565   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1566               "Forwarding reply for key %s to peer %s\n",
1567               GNUNET_h2s (key),
1568               GNUNET_i2s (target));
1569   GNUNET_STATISTICS_update (GDS_stats,
1570                             gettext_noop
1571                             ("# RESULT messages queued for transmission"), 1,
1572                             GNUNET_NO);
1573   env = GNUNET_MQ_msg_extra (prm,
1574                              msize,
1575                              GNUNET_MESSAGE_TYPE_DHT_P2P_RESULT);
1576   prm->type = htonl (type);
1577   prm->put_path_length = htonl (put_path_length);
1578   prm->get_path_length = htonl (get_path_length);
1579   prm->expiration_time = GNUNET_TIME_absolute_hton (expiration_time);
1580   prm->key = *key;
1581   paths = (struct GNUNET_PeerIdentity *) &prm[1];
1582   GNUNET_memcpy (paths,
1583                  put_path,
1584                  put_path_length * sizeof (struct GNUNET_PeerIdentity));
1585   GNUNET_memcpy (&paths[put_path_length],
1586                  get_path,
1587                  get_path_length * sizeof (struct GNUNET_PeerIdentity));
1588   GNUNET_memcpy (&paths[put_path_length + get_path_length],
1589                  data,
1590                  data_size);
1591   GNUNET_MQ_send (pi->mq,
1592                   env);
1593 }
1594
1595
1596 /**
1597  * To be called on core init/fail.
1598  *
1599  * @param cls service closure
1600  * @param identity the public identity of this peer
1601  */
1602 static void
1603 core_init (void *cls,
1604            const struct GNUNET_PeerIdentity *identity)
1605 {
1606   (void) cls;
1607   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
1608               "CORE called, I am %s\n",
1609               GNUNET_i2s (identity));
1610   my_identity = *identity;
1611   GNUNET_CRYPTO_hash (identity,
1612                       sizeof (struct GNUNET_PeerIdentity),
1613                       &my_identity_hash);
1614   GNUNET_SERVICE_resume (GDS_service);
1615 }
1616
1617
1618 /**
1619  * Check validity of a p2p put request.
1620  *
1621  * @param cls closure with the `struct PeerInfo` of the sender
1622  * @param message message
1623  * @return #GNUNET_OK if the message is valid
1624  */
1625 static int
1626 check_dht_p2p_put (void *cls,
1627                    const struct PeerPutMessage *put)
1628 {
1629   uint32_t putlen;
1630   uint16_t msize;
1631
1632   (void) cls;
1633   msize = ntohs (put->header.size);
1634   putlen = ntohl (put->put_path_length);
1635   if ((msize <
1636        sizeof (struct PeerPutMessage) +
1637        putlen * sizeof (struct GNUNET_PeerIdentity)) ||
1638       (putlen >
1639        GNUNET_MAX_MESSAGE_SIZE / sizeof (struct GNUNET_PeerIdentity)))
1640   {
1641     GNUNET_break_op (0);
1642     return GNUNET_SYSERR;
1643   }
1644   return GNUNET_OK;
1645 }
1646
1647
1648 /**
1649  * Core handler for p2p put requests.
1650  *
1651  * @param cls closure with the `struct PeerInfo` of the sender
1652  * @param message message
1653  */
1654 static void
1655 handle_dht_p2p_put (void *cls,
1656                     const struct PeerPutMessage *put)
1657 {
1658   struct PeerInfo *peer = cls;
1659   const struct GNUNET_PeerIdentity *put_path;
1660   const void *payload;
1661   uint32_t putlen;
1662   uint16_t msize;
1663   size_t payload_size;
1664   enum GNUNET_DHT_RouteOption options;
1665   struct GNUNET_CONTAINER_BloomFilter *bf;
1666   struct GNUNET_HashCode test_key;
1667   int forwarded;
1668   struct GNUNET_TIME_Absolute exp_time;
1669
1670   exp_time = GNUNET_TIME_absolute_ntoh (put->expiration_time);
1671   if (0 == GNUNET_TIME_absolute_get_remaining (exp_time).rel_value_us)
1672   {
1673     GNUNET_STATISTICS_update (GDS_stats,
1674                               gettext_noop ("# Expired PUTs discarded"),
1675                               1,
1676                               GNUNET_NO);
1677     return;
1678   }
1679   msize = ntohs (put->header.size);
1680   putlen = ntohl (put->put_path_length);
1681   GNUNET_STATISTICS_update (GDS_stats,
1682                             gettext_noop ("# P2P PUT requests received"),
1683                             1,
1684                             GNUNET_NO);
1685   GNUNET_STATISTICS_update (GDS_stats,
1686                             gettext_noop ("# P2P PUT bytes received"),
1687                             msize,
1688                             GNUNET_NO);
1689   put_path = (const struct GNUNET_PeerIdentity *) &put[1];
1690   payload = &put_path[putlen];
1691   options = ntohl (put->options);
1692   payload_size = msize - (sizeof (struct PeerPutMessage) +
1693                           putlen * sizeof (struct GNUNET_PeerIdentity));
1694
1695   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1696               "PUT for `%s' from %s\n",
1697               GNUNET_h2s (&put->key),
1698               GNUNET_i2s (peer->id));
1699   if (GNUNET_YES == log_route_details_stderr)
1700   {
1701     char *tmp;
1702     char *pp;
1703
1704     pp = GNUNET_STRINGS_pp2s (put_path,
1705                               putlen);
1706     tmp = GNUNET_strdup (GNUNET_i2s (&my_identity));
1707     LOG_TRAFFIC (GNUNET_ERROR_TYPE_DEBUG,
1708                  "R5N PUT %s: %s->%s (%u, %u=>%u, PP: %s)\n",
1709                  GNUNET_h2s (&put->key),
1710                  GNUNET_i2s (peer->id),
1711                  tmp,
1712                  ntohl(put->hop_count),
1713                  GNUNET_CRYPTO_hash_matching_bits (&peer->phash,
1714                                                    &put->key),
1715                  GNUNET_CRYPTO_hash_matching_bits (&my_identity_hash,
1716                                                    &put->key),
1717                  pp);
1718     GNUNET_free (pp);
1719     GNUNET_free (tmp);
1720   }
1721   switch (GNUNET_BLOCK_get_key
1722           (GDS_block_context,
1723            ntohl (put->type),
1724            payload,
1725            payload_size,
1726            &test_key))
1727   {
1728   case GNUNET_YES:
1729     if (0 != memcmp (&test_key,
1730                      &put->key,
1731                      sizeof (struct GNUNET_HashCode)))
1732     {
1733       char *put_s = GNUNET_strdup (GNUNET_h2s_full (&put->key));
1734
1735       GNUNET_break_op (0);
1736       GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
1737                   "PUT with key `%s' for block with key %s\n",
1738                   put_s,
1739                   GNUNET_h2s_full (&test_key));
1740       GNUNET_free (put_s);
1741       return;
1742     }
1743     break;
1744   case GNUNET_NO:
1745     GNUNET_break_op (0);
1746     return;
1747   case GNUNET_SYSERR:
1748     /* cannot verify, good luck */
1749     break;
1750   }
1751   if (ntohl (put->type) == GNUNET_BLOCK_TYPE_REGEX) /* FIXME: do for all tpyes */
1752   {
1753     switch (GNUNET_BLOCK_evaluate (GDS_block_context,
1754                                    ntohl (put->type),
1755                                    NULL, /* query group */
1756                                    GNUNET_BLOCK_EO_NONE,
1757                                    NULL,    /* query */
1758                                    NULL, 0, /* xquery */
1759                                    payload,
1760                                    payload_size))
1761     {
1762     case GNUNET_BLOCK_EVALUATION_OK_MORE:
1763     case GNUNET_BLOCK_EVALUATION_OK_LAST:
1764       break;
1765
1766     case GNUNET_BLOCK_EVALUATION_OK_DUPLICATE:
1767     case GNUNET_BLOCK_EVALUATION_RESULT_INVALID:
1768     case GNUNET_BLOCK_EVALUATION_RESULT_IRRELEVANT:
1769     case GNUNET_BLOCK_EVALUATION_REQUEST_VALID:
1770     case GNUNET_BLOCK_EVALUATION_REQUEST_INVALID:
1771     case GNUNET_BLOCK_EVALUATION_TYPE_NOT_SUPPORTED:
1772     default:
1773       GNUNET_break_op (0);
1774       return;
1775     }
1776   }
1777
1778   bf = GNUNET_CONTAINER_bloomfilter_init (put->bloomfilter,
1779                                           DHT_BLOOM_SIZE,
1780                                           GNUNET_CONSTANTS_BLOOMFILTER_K);
1781   GNUNET_break_op (GNUNET_YES ==
1782                    GNUNET_CONTAINER_bloomfilter_test (bf,
1783                                                       &peer->phash));
1784   {
1785     struct GNUNET_PeerIdentity pp[putlen + 1];
1786
1787     /* extend 'put path' by sender */
1788     if (0 != (options & GNUNET_DHT_RO_RECORD_ROUTE))
1789     {
1790 #if SANITY_CHECKS
1791       for (unsigned int i=0;i<=putlen;i++)
1792       {
1793         for (unsigned int j=0;j<i;j++)
1794         {
1795           GNUNET_break (0 != memcmp (&pp[i],
1796                                      &pp[j],
1797                                      sizeof (struct GNUNET_PeerIdentity)));
1798         }
1799         GNUNET_break (0 != memcmp (&pp[i],
1800                                    peer->id,
1801                                    sizeof (struct GNUNET_PeerIdentity)));
1802       }
1803 #endif
1804       GNUNET_memcpy (pp,
1805                      put_path,
1806                      putlen * sizeof (struct GNUNET_PeerIdentity));
1807       pp[putlen] = *peer->id;
1808       putlen++;
1809     }
1810     else
1811       putlen = 0;
1812
1813     /* give to local clients */
1814     GDS_CLIENTS_handle_reply (exp_time,
1815                               &put->key,
1816                               0,
1817                               NULL,
1818                               putlen,
1819                               pp,
1820                               ntohl (put->type),
1821                               payload_size,
1822                               payload);
1823     /* store locally */
1824     if ((0 != (options & GNUNET_DHT_RO_DEMULTIPLEX_EVERYWHERE)) ||
1825         (GDS_am_closest_peer (&put->key, bf)))
1826       GDS_DATACACHE_handle_put (exp_time,
1827                                 &put->key,
1828                                 putlen,
1829                                 pp,
1830                                 ntohl (put->type),
1831                                 payload_size,
1832                                 payload);
1833     /* route to other peers */
1834     forwarded = GDS_NEIGHBOURS_handle_put (ntohl (put->type),
1835                                            options,
1836                                            ntohl (put->desired_replication_level),
1837                                            exp_time,
1838                                            ntohl (put->hop_count),
1839                                            bf,
1840                                            &put->key,
1841                                            putlen,
1842                                            pp,
1843                                            payload,
1844                                            payload_size);
1845     /* notify monitoring clients */
1846     GDS_CLIENTS_process_put (options
1847                              | ( (GNUNET_OK == forwarded)
1848                                  ? GNUNET_DHT_RO_LAST_HOP
1849                                  : 0 ),
1850                              ntohl (put->type),
1851                              ntohl (put->hop_count),
1852                              ntohl (put->desired_replication_level),
1853                              putlen, pp,
1854                              exp_time,
1855                              &put->key,
1856                              payload,
1857                              payload_size);
1858   }
1859   GNUNET_CONTAINER_bloomfilter_free (bf);
1860 }
1861
1862
1863 /**
1864  * We have received a FIND PEER request.  Send matching
1865  * HELLOs back.
1866  *
1867  * @param sender sender of the FIND PEER request
1868  * @param key peers close to this key are desired
1869  * @param bg group for filtering peers
1870  */
1871 static void
1872 handle_find_peer (const struct GNUNET_PeerIdentity *sender,
1873                   const struct GNUNET_HashCode *key,
1874                   struct GNUNET_BLOCK_Group *bg)
1875 {
1876   int bucket_idx;
1877   struct PeerBucket *bucket;
1878   struct PeerInfo *peer;
1879   unsigned int choice;
1880   const struct GNUNET_HELLO_Message *hello;
1881   size_t hello_size;
1882
1883   /* first, check about our own HELLO */
1884   if (NULL != GDS_my_hello)
1885   {
1886     hello_size = GNUNET_HELLO_size ((const struct GNUNET_HELLO_Message *) GDS_my_hello);
1887     GNUNET_break (hello_size >= sizeof (struct GNUNET_MessageHeader));
1888     if (GNUNET_BLOCK_EVALUATION_OK_MORE ==
1889         GNUNET_BLOCK_evaluate (GDS_block_context,
1890                                GNUNET_BLOCK_TYPE_DHT_HELLO,
1891                                bg,
1892                                GNUNET_BLOCK_EO_LOCAL_SKIP_CRYPTO,
1893                                &my_identity_hash,
1894                                NULL, 0,
1895                                GDS_my_hello,
1896                                hello_size))
1897     {
1898       GDS_NEIGHBOURS_handle_reply (sender,
1899                                    GNUNET_BLOCK_TYPE_DHT_HELLO,
1900                                    GNUNET_TIME_relative_to_absolute (hello_expiration),
1901                                    key,
1902                                    0,
1903                                    NULL,
1904                                    0,
1905                                    NULL,
1906                                    GDS_my_hello,
1907                                    hello_size);
1908     }
1909     else
1910     {
1911       GNUNET_STATISTICS_update (GDS_stats,
1912                                 gettext_noop ("# FIND PEER requests ignored due to Bloomfilter"),
1913                                 1,
1914                                 GNUNET_NO);
1915     }
1916   }
1917   else
1918   {
1919     GNUNET_STATISTICS_update (GDS_stats,
1920                               gettext_noop ("# FIND PEER requests ignored due to lack of HELLO"),
1921                               1,
1922                               GNUNET_NO);
1923   }
1924
1925   /* then, also consider sending a random HELLO from the closest bucket */
1926   if (0 == memcmp (&my_identity_hash,
1927                    key,
1928                    sizeof (struct GNUNET_HashCode)))
1929     bucket_idx = closest_bucket;
1930   else
1931     bucket_idx = GNUNET_MIN ((int) closest_bucket,
1932                              find_bucket (key));
1933   if (bucket_idx < 0)
1934     return;
1935   bucket = &k_buckets[bucket_idx];
1936   if (bucket->peers_size == 0)
1937     return;
1938   choice = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK,
1939                                      bucket->peers_size);
1940   peer = bucket->head;
1941   while (choice > 0)
1942   {
1943     GNUNET_assert (NULL != peer);
1944     peer = peer->next;
1945     choice--;
1946   }
1947   choice = bucket->peers_size;
1948   do
1949   {
1950     peer = peer->next;
1951     if (0 == choice--)
1952       return;                   /* no non-masked peer available */
1953     if (NULL == peer)
1954       peer = bucket->head;
1955     hello = GDS_HELLO_get (peer->id);
1956   } while ( (NULL == hello) ||
1957             (GNUNET_BLOCK_EVALUATION_OK_MORE !=
1958              GNUNET_BLOCK_evaluate (GDS_block_context,
1959                                     GNUNET_BLOCK_TYPE_DHT_HELLO,
1960                                     bg,
1961                                     GNUNET_BLOCK_EO_LOCAL_SKIP_CRYPTO,
1962                                     &peer->phash,
1963                                     NULL, 0,
1964                                     hello,
1965                                     (hello_size = GNUNET_HELLO_size (hello)))) );
1966   GDS_NEIGHBOURS_handle_reply (sender,
1967                                GNUNET_BLOCK_TYPE_DHT_HELLO,
1968                                GNUNET_TIME_relative_to_absolute
1969                                (GNUNET_CONSTANTS_HELLO_ADDRESS_EXPIRATION),
1970                                key,
1971                                0,
1972                                NULL,
1973                                0,
1974                                NULL,
1975                                hello,
1976                                hello_size);
1977 }
1978
1979
1980 /**
1981  * Handle a result from local datacache for a GET operation.
1982  *
1983  * @param cls the `struct PeerInfo` for which this is a reply
1984  * @param type type of the block
1985  * @param expiration_time when does the content expire
1986  * @param key key for the content
1987  * @param put_path_length number of entries in @a put_path
1988  * @param put_path peers the original PUT traversed (if tracked)
1989  * @param get_path_length number of entries in @a get_path
1990  * @param get_path peers this reply has traversed so far (if tracked)
1991  * @param data payload of the reply
1992  * @param data_size number of bytes in @a data
1993  */
1994 static void
1995 handle_local_result (void *cls,
1996                      enum GNUNET_BLOCK_Type type,
1997                      struct GNUNET_TIME_Absolute expiration_time,
1998                      const struct GNUNET_HashCode *key,
1999                      unsigned int put_path_length,
2000                      const struct GNUNET_PeerIdentity *put_path,
2001                      unsigned int get_path_length,
2002                      const struct GNUNET_PeerIdentity *get_path,
2003                      const void *data,
2004                      size_t data_size)
2005 {
2006   struct PeerInfo *peer = cls;
2007   char *pp;
2008
2009   pp = GNUNET_STRINGS_pp2s (put_path,
2010                             put_path_length);
2011   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
2012               "Found local result for %s (PP: %s)\n",
2013               GNUNET_h2s (key),
2014               pp);
2015   GNUNET_free (pp);
2016   GDS_NEIGHBOURS_handle_reply (peer->id,
2017                                type,
2018                                expiration_time,
2019                                key,
2020                                put_path_length, put_path,
2021                                get_path_length, get_path,
2022                                data, data_size);
2023 }
2024
2025
2026 /**
2027  * Check validity of p2p get request.
2028  *
2029  * @param cls closure with the `struct PeerInfo` of the sender
2030  * @param get the message
2031  * @return #GNUNET_OK if the message is well-formed
2032  */
2033 static int
2034 check_dht_p2p_get (void *cls,
2035                    const struct PeerGetMessage *get)
2036 {
2037   uint32_t xquery_size;
2038   uint16_t msize;
2039
2040   (void) cls;
2041   msize = ntohs (get->header.size);
2042   xquery_size = ntohl (get->xquery_size);
2043   if (msize < sizeof (struct PeerGetMessage) + xquery_size)
2044   {
2045     GNUNET_break_op (0);
2046     return GNUNET_SYSERR;
2047   }
2048   return GNUNET_OK;
2049 }
2050
2051
2052 /**
2053  * Core handler for p2p get requests.
2054  *
2055  * @param cls closure with the `struct PeerInfo` of the sender
2056  * @param get the message
2057  */
2058 static void
2059 handle_dht_p2p_get (void *cls,
2060                     const struct PeerGetMessage *get)
2061 {
2062   struct PeerInfo *peer = cls;
2063   uint32_t xquery_size;
2064   size_t reply_bf_size;
2065   uint16_t msize;
2066   enum GNUNET_BLOCK_Type type;
2067   enum GNUNET_DHT_RouteOption options;
2068   enum GNUNET_BLOCK_EvaluationResult eval;
2069   struct GNUNET_BLOCK_Group *bg;
2070   struct GNUNET_CONTAINER_BloomFilter *peer_bf;
2071   const char *xquery;
2072   int forwarded;
2073
2074   /* parse and validate message */
2075   msize = ntohs (get->header.size);
2076   xquery_size = ntohl (get->xquery_size);
2077   reply_bf_size = msize - (sizeof (struct PeerGetMessage) + xquery_size);
2078   type = ntohl (get->type);
2079   options = ntohl (get->options);
2080   xquery = (const char *) &get[1];
2081   GNUNET_STATISTICS_update (GDS_stats,
2082                             gettext_noop ("# P2P GET requests received"),
2083                             1,
2084                             GNUNET_NO);
2085   GNUNET_STATISTICS_update (GDS_stats,
2086                             gettext_noop ("# P2P GET bytes received"),
2087                             msize,
2088                             GNUNET_NO);
2089   if (GNUNET_YES == log_route_details_stderr)
2090   {
2091     char *tmp;
2092
2093     tmp = GNUNET_strdup (GNUNET_i2s (&my_identity));
2094     LOG_TRAFFIC (GNUNET_ERROR_TYPE_DEBUG,
2095                  "R5N GET %s: %s->%s (%u, %u=>%u) xq: %.*s\n",
2096                  GNUNET_h2s (&get->key),
2097                  GNUNET_i2s (peer->id),
2098                  tmp,
2099                  ntohl(get->hop_count),
2100                  GNUNET_CRYPTO_hash_matching_bits (&peer->phash,
2101                                                    &get->key),
2102                  GNUNET_CRYPTO_hash_matching_bits (&my_identity_hash,
2103                                                    &get->key),
2104                  ntohl(get->xquery_size),
2105                  xquery);
2106     GNUNET_free (tmp);
2107   }
2108   eval
2109     = GNUNET_BLOCK_evaluate (GDS_block_context,
2110                              type,
2111                              NULL,
2112                              GNUNET_BLOCK_EO_NONE,
2113                              &get->key,
2114                              xquery,
2115                              xquery_size,
2116                              NULL,
2117                              0);
2118   if (eval != GNUNET_BLOCK_EVALUATION_REQUEST_VALID)
2119   {
2120     /* request invalid or block type not supported */
2121     GNUNET_break_op (eval == GNUNET_BLOCK_EVALUATION_TYPE_NOT_SUPPORTED);
2122     return;
2123   }
2124   peer_bf = GNUNET_CONTAINER_bloomfilter_init (get->bloomfilter,
2125                                                DHT_BLOOM_SIZE,
2126                                                GNUNET_CONSTANTS_BLOOMFILTER_K);
2127   GNUNET_break_op (GNUNET_YES ==
2128                    GNUNET_CONTAINER_bloomfilter_test (peer_bf,
2129                                                       &peer->phash));
2130   bg = GNUNET_BLOCK_group_create (GDS_block_context,
2131                                   type,
2132                                   get->bf_mutator,
2133                                   &xquery[xquery_size],
2134                                   reply_bf_size,
2135                                   "filter-size",
2136                                   reply_bf_size,
2137                                   NULL);
2138   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
2139               "GET for %s at %s after %u hops\n",
2140               GNUNET_h2s (&get->key),
2141               GNUNET_i2s (&my_identity),
2142               (unsigned int) ntohl (get->hop_count));
2143   /* local lookup (this may update the reply_bf) */
2144   if ((0 != (options & GNUNET_DHT_RO_DEMULTIPLEX_EVERYWHERE)) ||
2145       (GDS_am_closest_peer (&get->key,
2146                         peer_bf)))
2147   {
2148     if ((0 != (options & GNUNET_DHT_RO_FIND_PEER)))
2149     {
2150       GNUNET_STATISTICS_update (GDS_stats,
2151                                 gettext_noop ("# P2P FIND PEER requests processed"),
2152                                 1,
2153                                 GNUNET_NO);
2154       handle_find_peer (peer->id,
2155                         &get->key,
2156                         bg);
2157     }
2158     else
2159     {
2160       eval = GDS_DATACACHE_handle_get (&get->key,
2161                                        type,
2162                                        xquery,
2163                                        xquery_size,
2164                                        bg,
2165                                        &handle_local_result,
2166                                        peer);
2167     }
2168   }
2169   else
2170   {
2171     GNUNET_STATISTICS_update (GDS_stats,
2172                               gettext_noop ("# P2P GET requests ONLY routed"),
2173                               1,
2174                               GNUNET_NO);
2175   }
2176
2177   /* remember request for routing replies */
2178   GDS_ROUTING_add (peer->id,
2179                         type,
2180                         bg, /* bg now owned by routing, but valid at least until end of this function! */
2181                         options,
2182                         &get->key,
2183                         xquery,
2184                         xquery_size);
2185
2186   /* P2P forwarding */
2187   forwarded = GNUNET_NO;
2188   if (eval != GNUNET_BLOCK_EVALUATION_OK_LAST)
2189     forwarded = GDS_NEIGHBOURS_handle_get (type,
2190                                            options,
2191                                            ntohl (get->desired_replication_level),
2192                                            ntohl (get->hop_count),
2193                                            &get->key,
2194                                            xquery,
2195                                            xquery_size,
2196                                            bg,
2197                                            peer_bf);
2198   GDS_CLIENTS_process_get (options
2199                            | (GNUNET_OK == forwarded)
2200                            ? GNUNET_DHT_RO_LAST_HOP : 0,
2201                            type,
2202                            ntohl (get->hop_count),
2203                            ntohl (get->desired_replication_level),
2204                            0,
2205                            NULL,
2206                            &get->key);
2207
2208   /* clean up; note that 'bg' is owned by routing now! */
2209   GNUNET_CONTAINER_bloomfilter_free (peer_bf);
2210 }
2211
2212
2213 /**
2214  * Check validity of p2p result message.
2215  *
2216  * @param cls closure
2217  * @param message message
2218  * @return #GNUNET_YES if the message is well-formed
2219  */
2220 static int
2221 check_dht_p2p_result (void *cls,
2222                       const struct PeerResultMessage *prm)
2223 {
2224   uint32_t get_path_length;
2225   uint32_t put_path_length;
2226   uint16_t msize;
2227
2228   (void) cls;
2229   msize = ntohs (prm->header.size);
2230   put_path_length = ntohl (prm->put_path_length);
2231   get_path_length = ntohl (prm->get_path_length);
2232   if ((msize <
2233        sizeof (struct PeerResultMessage) + (get_path_length +
2234                                             put_path_length) *
2235        sizeof (struct GNUNET_PeerIdentity)) ||
2236       (get_path_length >
2237        GNUNET_MAX_MESSAGE_SIZE / sizeof (struct GNUNET_PeerIdentity)) ||
2238       (put_path_length >
2239        GNUNET_MAX_MESSAGE_SIZE / sizeof (struct GNUNET_PeerIdentity)))
2240   {
2241     GNUNET_break_op (0);
2242     return GNUNET_SYSERR;
2243   }
2244   return GNUNET_OK;
2245 }
2246
2247
2248 /**
2249  * Process a reply, after the @a get_path has been updated.
2250  *
2251  * @param expiration_time when does the reply expire
2252  * @param key key matching the query
2253  * @param get_path_length number of entries in @a get_path
2254  * @param get_path path the reply has taken
2255  * @param put_path_length number of entries in @a put_path
2256  * @param put_path path the PUT has taken
2257  * @param type type of the block
2258  * @param data_size number of bytes in @a data
2259  * @param data payload of the reply
2260  */
2261 static void
2262 process_reply_with_path (struct GNUNET_TIME_Absolute expiration_time,
2263                          const struct GNUNET_HashCode *key,
2264                          unsigned int get_path_length,
2265                          const struct GNUNET_PeerIdentity *get_path,
2266                          unsigned int put_path_length,
2267                          const struct GNUNET_PeerIdentity *put_path,
2268                          enum GNUNET_BLOCK_Type type,
2269                          size_t data_size,
2270                          const void *data)
2271 {
2272   /* forward to local clients */
2273   GDS_CLIENTS_handle_reply (expiration_time,
2274                             key,
2275                             get_path_length,
2276                             get_path,
2277                             put_path_length,
2278                             put_path,
2279                             type,
2280                             data_size,
2281                             data);
2282   GDS_CLIENTS_process_get_resp (type,
2283                                 get_path,
2284                                 get_path_length,
2285                                 put_path,
2286                                 put_path_length,
2287                                 expiration_time,
2288                                 key,
2289                                 data,
2290                                 data_size);
2291   if (GNUNET_YES == cache_results)
2292   {
2293     struct GNUNET_PeerIdentity xput_path[get_path_length + 1 + put_path_length];
2294
2295     GNUNET_memcpy (xput_path,
2296                    put_path,
2297                    put_path_length * sizeof (struct GNUNET_PeerIdentity));
2298     GNUNET_memcpy (&xput_path[put_path_length],
2299                    get_path,
2300                    get_path_length * sizeof (struct GNUNET_PeerIdentity));
2301
2302     GDS_DATACACHE_handle_put (expiration_time,
2303                               key,
2304                               get_path_length + put_path_length,
2305                               xput_path,
2306                               type,
2307                               data_size,
2308                               data);
2309   }
2310   /* forward to other peers */
2311   GDS_ROUTING_process (type,
2312                        expiration_time,
2313                        key,
2314                        put_path_length,
2315                        put_path,
2316                        get_path_length,
2317                        get_path,
2318                        data,
2319                        data_size);
2320 }
2321
2322
2323 /**
2324  * Core handler for p2p result messages.
2325  *
2326  * @param cls closure
2327  * @param message message
2328  */
2329 static void
2330 handle_dht_p2p_result (void *cls,
2331                        const struct PeerResultMessage *prm)
2332 {
2333   struct PeerInfo *peer = cls;
2334   const struct GNUNET_PeerIdentity *put_path;
2335   const struct GNUNET_PeerIdentity *get_path;
2336   const void *data;
2337   uint32_t get_path_length;
2338   uint32_t put_path_length;
2339   uint16_t msize;
2340   size_t data_size;
2341   enum GNUNET_BLOCK_Type type;
2342   struct GNUNET_TIME_Absolute exp_time;
2343
2344   /* parse and validate message */
2345   exp_time = GNUNET_TIME_absolute_ntoh (prm->expiration_time);
2346   if (0 == GNUNET_TIME_absolute_get_remaining (exp_time).rel_value_us)
2347   {
2348     GNUNET_STATISTICS_update (GDS_stats,
2349                               gettext_noop ("# Expired results discarded"),
2350                               1,
2351                               GNUNET_NO);
2352     return;
2353   }
2354   msize = ntohs (prm->header.size);
2355   put_path_length = ntohl (prm->put_path_length);
2356   get_path_length = ntohl (prm->get_path_length);
2357   put_path = (const struct GNUNET_PeerIdentity *) &prm[1];
2358   get_path = &put_path[put_path_length];
2359   type = ntohl (prm->type);
2360   data = (const void *) &get_path[get_path_length];
2361   data_size = msize - (sizeof (struct PeerResultMessage) +
2362                        (get_path_length +
2363                         put_path_length) * sizeof (struct GNUNET_PeerIdentity));
2364   GNUNET_STATISTICS_update (GDS_stats,
2365                             gettext_noop ("# P2P RESULTS received"),
2366                             1,
2367                             GNUNET_NO);
2368   GNUNET_STATISTICS_update (GDS_stats,
2369                             gettext_noop ("# P2P RESULT bytes received"),
2370                             msize,
2371                             GNUNET_NO);
2372   if (GNUNET_YES == log_route_details_stderr)
2373   {
2374     char *tmp;
2375     char *pp;
2376     char *gp;
2377
2378     gp = GNUNET_STRINGS_pp2s (get_path,
2379                               get_path_length);
2380     pp = GNUNET_STRINGS_pp2s (put_path,
2381                               put_path_length);
2382     tmp = GNUNET_strdup (GNUNET_i2s (&my_identity));
2383     LOG_TRAFFIC (GNUNET_ERROR_TYPE_DEBUG,
2384                  "R5N RESULT %s: %s->%s (GP: %s, PP: %s)\n",
2385                  GNUNET_h2s (&prm->key),
2386                  GNUNET_i2s (peer->id),
2387                  tmp,
2388                  gp,
2389                  pp);
2390     GNUNET_free (gp);
2391     GNUNET_free (pp);
2392     GNUNET_free (tmp);
2393   }
2394   /* if we got a HELLO, consider it for our own routing table */
2395   if (GNUNET_BLOCK_TYPE_DHT_HELLO == type)
2396   {
2397     const struct GNUNET_MessageHeader *h;
2398     struct GNUNET_PeerIdentity pid;
2399
2400     /* Should be a HELLO, validate and consider using it! */
2401     if (data_size < sizeof (struct GNUNET_HELLO_Message))
2402     {
2403       GNUNET_break_op (0);
2404       return;
2405     }
2406     h = data;
2407     if (data_size != ntohs (h->size))
2408     {
2409       GNUNET_break_op (0);
2410       return;
2411     }
2412     if (GNUNET_OK !=
2413         GNUNET_HELLO_get_id ((const struct GNUNET_HELLO_Message *) h,
2414                              &pid))
2415     {
2416       GNUNET_break_op (0);
2417       return;
2418     }
2419     if ( (GNUNET_YES != disable_try_connect) &&
2420          (0 != memcmp (&my_identity,
2421                        &pid,
2422                        sizeof (struct GNUNET_PeerIdentity))) )
2423       try_connect (&pid,
2424                    h);
2425   }
2426
2427   /* First, check if 'peer' is already on the path, and if
2428      so, truncate it instead of expanding. */
2429   for (unsigned int i=0;i<=get_path_length;i++)
2430     if (0 == memcmp (&get_path[i],
2431                      peer->id,
2432                      sizeof (struct GNUNET_PeerIdentity)))
2433     {
2434       process_reply_with_path (exp_time,
2435                                &prm->key,
2436                                i,
2437                                get_path,
2438                                put_path_length,
2439                                put_path,
2440                                type,
2441                                data_size,
2442                                data);
2443       return;
2444     }
2445
2446   /* Need to append 'peer' to 'get_path' (normal case) */
2447   {
2448     struct GNUNET_PeerIdentity xget_path[get_path_length + 1];
2449
2450     GNUNET_memcpy (xget_path,
2451                    get_path,
2452                    get_path_length * sizeof (struct GNUNET_PeerIdentity));
2453     xget_path[get_path_length] = *peer->id;
2454
2455     process_reply_with_path (exp_time,
2456                              &prm->key,
2457                              get_path_length + 1,
2458                              xget_path,
2459                              put_path_length,
2460                              put_path,
2461                              type,
2462                              data_size,
2463                              data);
2464   }
2465 }
2466
2467
2468 /**
2469  * Initialize neighbours subsystem.
2470  *
2471  * @return #GNUNET_OK on success, #GNUNET_SYSERR on error
2472  */
2473 int
2474 GDS_NEIGHBOURS_init ()
2475 {
2476   struct GNUNET_MQ_MessageHandler core_handlers[] = {
2477     GNUNET_MQ_hd_var_size (dht_p2p_get,
2478                            GNUNET_MESSAGE_TYPE_DHT_P2P_GET,
2479                            struct PeerGetMessage,
2480                            NULL),
2481     GNUNET_MQ_hd_var_size (dht_p2p_put,
2482                            GNUNET_MESSAGE_TYPE_DHT_P2P_PUT,
2483                            struct PeerPutMessage,
2484                            NULL),
2485     GNUNET_MQ_hd_var_size (dht_p2p_result,
2486                            GNUNET_MESSAGE_TYPE_DHT_P2P_RESULT,
2487                            struct PeerResultMessage,
2488                            NULL),
2489     GNUNET_MQ_handler_end ()
2490   };
2491   unsigned long long temp_config_num;
2492
2493   disable_try_connect
2494     = GNUNET_CONFIGURATION_get_value_yesno (GDS_cfg,
2495                                             "DHT",
2496                                             "DISABLE_TRY_CONNECT");
2497   if (GNUNET_OK ==
2498       GNUNET_CONFIGURATION_get_value_number (GDS_cfg,
2499                                              "DHT",
2500                                              "bucket_size",
2501                                              &temp_config_num))
2502     bucket_size = (unsigned int) temp_config_num;
2503   cache_results
2504     = GNUNET_CONFIGURATION_get_value_yesno (GDS_cfg,
2505                                             "DHT",
2506                                             "CACHE_RESULTS");
2507
2508   log_route_details_stderr =
2509     (NULL != getenv("GNUNET_DHT_ROUTE_DEBUG")) ? GNUNET_YES : GNUNET_NO;
2510   ats_ch = GNUNET_ATS_connectivity_init (GDS_cfg);
2511   core_api = GNUNET_CORE_connect (GDS_cfg,
2512                                   NULL,
2513                                   &core_init,
2514                                   &handle_core_connect,
2515                                   &handle_core_disconnect,
2516                                   core_handlers);
2517   if (NULL == core_api)
2518     return GNUNET_SYSERR;
2519   all_connected_peers = GNUNET_CONTAINER_multipeermap_create (256,
2520                                                               GNUNET_YES);
2521   all_desired_peers = GNUNET_CONTAINER_multipeermap_create (256,
2522                                                             GNUNET_NO);
2523   return GNUNET_OK;
2524 }
2525
2526
2527 /**
2528  * Shutdown neighbours subsystem.
2529  */
2530 void
2531 GDS_NEIGHBOURS_done ()
2532 {
2533   if (NULL == core_api)
2534     return;
2535   GNUNET_CORE_disconnect (core_api);
2536   core_api = NULL;
2537   GNUNET_assert (0 ==
2538                  GNUNET_CONTAINER_multipeermap_size (all_connected_peers));
2539   GNUNET_CONTAINER_multipeermap_destroy (all_connected_peers);
2540   all_connected_peers = NULL;
2541   GNUNET_CONTAINER_multipeermap_iterate (all_desired_peers,
2542                                          &free_connect_info,
2543                                          NULL);
2544   GNUNET_CONTAINER_multipeermap_destroy (all_desired_peers);
2545   all_desired_peers = NULL;
2546   GNUNET_ATS_connectivity_done (ats_ch);
2547   ats_ch = NULL;
2548   GNUNET_assert (NULL == find_peer_task);
2549 }
2550
2551
2552 /**
2553  * Get the ID of the local node.
2554  *
2555  * @return identity of the local node
2556  */
2557 struct GNUNET_PeerIdentity *
2558 GDS_NEIGHBOURS_get_id ()
2559 {
2560   return &my_identity;
2561 }
2562
2563
2564 /* end of gnunet-service-dht_neighbours.c */