src/dv/gnunet-service-dv.c

   1 /*
   2      This file is part of GNUnet.
   3      (C) 2013 Christian Grothoff (and other contributing authors)
   4
   5      GNUnet is free software; you can redistribute it and/or modify
   6      it under the terms of the GNU General Public License as published
   7      by the Free Software Foundation; either version 3, or (at your
   8      option) any later version.
   9
  10      GNUnet is distributed in the hope that it will be useful, but
  11      WITHOUT ANY WARRANTY; without even the implied warranty of
  12      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13      General Public License for more details.
  14
  15      You should have received a copy of the GNU General Public License
  16      along with GNUnet; see the file COPYING.  If not, write to the
  17      Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18      Boston, MA 02111-1307, USA.
  19 */
  20
  21 /**
  22  * @file dv/gnunet-service-dv.c
  23  * @brief the distance vector service, primarily handles gossip of nearby
  24  * peers and sending/receiving DV messages from core and decapsulating
  25  * them
  26  *
  27  * @author Christian Grothoff
  28  * @author Nathan Evans
  29  *
  30  * TODO:
  31  * - distance updates are not properly communicate to US by core/transport/ats
  32  */
  33 #include "platform.h"
  34 #include "gnunet_util_lib.h"
  35 #include "gnunet_protocols.h"
  36 #include "gnunet_core_service.h"
  37 #include "gnunet_hello_lib.h"
  38 #include "gnunet_peerinfo_service.h"
  39 #include "gnunet_statistics_service.h"
  40 #include "gnunet_consensus_service.h"
  41 #include "dv.h"
  42 #include <gcrypt.h>
  43
  44
  45 /**
  46  * How often do we establish the consensu?
  47  */
  48 #define GNUNET_DV_CONSENSUS_FREQUENCY GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_MINUTES, 5)
  49
  50 /**
  51  * Maximum number of messages we queue per peer.
  52  */
  53 #define MAX_QUEUE_SIZE 16
  54
  55 /**
  56  * Maximum number of messages we queue towards the clients/plugin.
  57  */
  58 #define MAX_QUEUE_SIZE_PLUGIN 1024
  59
  60 /**
  61  * The default fisheye depth, from how many hops away will
  62  * we keep peers?
  63  */
  64 #define DEFAULT_FISHEYE_DEPTH 3
  65
  66 /**
  67  * How many hops is a direct neighbor away?
  68  */
  69 #define DIRECT_NEIGHBOR_COST 1
  70
  71
  72 GNUNET_NETWORK_STRUCT_BEGIN
  73
  74 /**
  75  * Information about a peer DV can route to.  These entries are what
  76  * we use as the binary format to establish consensus to create our
  77  * routing table and as the address format in the HELLOs.
  78  */
  79 struct Target
  80 {
  81
  82   /**
  83    * Identity of the peer we can reach.
  84    */
  85   struct GNUNET_PeerIdentity peer;
  86
  87   /**
  88    * How many hops (1-3) is this peer away? in network byte order
  89    */
  90   uint32_t distance GNUNET_PACKED;
  91
  92 };
  93
  94
  95 /**
  96  * Message exchanged between DV services (via core), requesting a
  97  * message to be routed.
  98  */
  99 struct RouteMessage
 100 {
 101   /**
 102    * Type: GNUNET_MESSAGE_TYPE_DV_ROUTE
 103    */
 104   struct GNUNET_MessageHeader header;
 105
 106   /**
 107    * Expected (remaining) distance.  Must be always smaller than
 108    * DEFAULT_FISHEYE_DEPTH, should be zero at the target.  Must
 109    * be decremented by one at each hop.  Peers must not forward
 110    * these messages further once the counter has reached zero.
 111    */
 112   uint32_t distance GNUNET_PACKED;
 113
 114   /**
 115    * The (actual) target of the message (this peer, if distance is zero).
 116    */
 117   struct GNUNET_PeerIdentity target;
 118
 119   /**
 120    * The (actual) sender of the message.
 121    */
 122   struct GNUNET_PeerIdentity sender;
 123
 124 };
 125
 126 GNUNET_NETWORK_STRUCT_END
 127
 128
 129 /**
 130  * Linked list of messages to send to clients.
 131  */
 132 struct PendingMessage
 133 {
 134   /**
 135    * Pointer to next item in the list
 136    */
 137   struct PendingMessage *next;
 138
 139   /**
 140    * Pointer to previous item in the list
 141    */
 142   struct PendingMessage *prev;
 143
 144   /**
 145    * Actual message to be sent, allocated after this struct.
 146    */
 147   const struct GNUNET_MessageHeader *msg;
 148
 149   /**
 150    * Ultimate target for the message.
 151    */
 152   struct GNUNET_PeerIdentity ultimate_target;
 153
 154   /**
 155    * Unique ID of the message.
 156    */
 157   uint32_t uid;
 158
 159 };
 160
 161
 162 /**
 163  * Information about a direct neighbor (core-level, excluding
 164  * DV-links, only DV-enabled peers).
 165  */
 166 struct DirectNeighbor
 167 {
 168
 169   /**
 170    * Identity of the peer.
 171    */
 172   struct GNUNET_PeerIdentity peer;
 173
 174   /**
 175    * Head of linked list of messages to send to this peer.
 176    */
 177   struct PendingMessage *pm_head;
 178
 179   /**
 180    * Tail of linked list of messages to send to this peer.
 181    */
 182   struct PendingMessage *pm_tail;
 183
 184   /**
 185    * Transmit handle to core service.
 186    */
 187   struct GNUNET_CORE_TransmitHandle *cth;
 188
 189   /**
 190    * Routing table of the neighbor, NULL if not yet established.
 191    * Keys are peer identities, values are 'struct Target' entries.
 192    * Note that the distances in the targets are from the point-of-view
 193    * of the peer, not from us!
 194    */
 195   struct GNUNET_CONTAINER_MultiHashMap *neighbor_table;
 196
 197   /**
 198    * Updated routing table of the neighbor, under construction,
 199    * NULL if we are not currently building it.
 200    * Keys are peer identities, values are 'struct Target' entries.
 201    * Note that the distances in the targets are from the point-of-view
 202    * of the peer, not from us!
 203    */
 204   struct GNUNET_CONTAINER_MultiHashMap *neighbor_table_consensus;
 205
 206   /**
 207    * Active consensus, if we are currently synchronizing the
 208    * routing tables.
 209    */
 210   struct GNUNET_CONSENSUS_Handle *consensus;
 211
 212   /**
 213    * ID of the task we use to (periodically) update our consensus
 214    * with this peer.
 215    */
 216   GNUNET_SCHEDULER_TaskIdentifier consensus_task;
 217
 218   /**
 219    * At what offset are we, with respect to inserting our own routes
 220    * into the consensus?
 221    */
 222   unsigned int consensus_insertion_offset;
 223
 224   /**
 225    * At what distance are we, with respect to inserting our own routes
 226    * into the consensus?
 227    */
 228   unsigned int consensus_insertion_distance;
 229
 230   /**
 231    * Number of messages currently in the 'pm_XXXX'-DLL.
 232    */
 233   unsigned int pm_queue_size;
 234
 235   /**
 236    * Flag set within 'check_target_removed' to trigger full global route refresh.
 237    */
 238   int target_removed;
 239
 240 };
 241
 242
 243 /**
 244  * A route includes information about the next hop,
 245  * the target, and the ultimate distance to the
 246  * target.
 247  */
 248 struct Route
 249 {
 250
 251   /**
 252    * Which peer do we need to forward the message to?
 253    */
 254   struct DirectNeighbor *next_hop;
 255
 256   /**
 257    * What would be the target, and how far is it away?
 258    */
 259   struct Target target;
 260
 261   /**
 262    * Offset of this target in the respective consensus set.
 263    */
 264   unsigned int set_offset;
 265
 266 };
 267
 268
 269 /**
 270  * Set of targets we bring to a consensus; all targets in a set have a
 271  * distance equal to the sets distance (which is implied by the array
 272  * index of the set).
 273  */
 274 struct ConsensusSet
 275 {
 276
 277   /**
 278    * Array of targets in the set, may include NULL entries if a
 279    * neighbor has disconnected; the targets are allocated with the
 280    * respective container (all_routes), not here.
 281    */
 282   struct Route **targets;
 283
 284   /**
 285    * Size of the 'targets' array.
 286    */
 287   unsigned int array_length;
 288
 289 };
 290
 291
 292 /**
 293  * Hashmap of all of our direct neighbors (no DV routing).
 294  */
 295 static struct GNUNET_CONTAINER_MultiHashMap *direct_neighbors;
 296
 297 /**
 298  * Hashmap with all routes that we currently support; contains
 299  * routing information for all peers from distance 2
 300  * up to distance DEFAULT_FISHEYE_DEPTH.
 301  */
 302 static struct GNUNET_CONTAINER_MultiHashMap *all_routes;
 303
 304 /**
 305  * Array of consensus sets we expose to the outside world.  Sets
 306  * are structured by the distance to the target.
 307  */
 308 static struct ConsensusSet consensi[DEFAULT_FISHEYE_DEPTH - 1];
 309
 310 /**
 311  * Handle to the core service api.
 312  */
 313 static struct GNUNET_CORE_Handle *core_api;
 314
 315 /**
 316  * The identity of our peer.
 317  */
 318 static struct GNUNET_PeerIdentity my_identity;
 319
 320 /**
 321  * The configuration for this service.
 322  */
 323 static const struct GNUNET_CONFIGURATION_Handle *cfg;
 324
 325 /**
 326  * The client, the DV plugin connected to us (or an event monitor).
 327  * Hopefully this client will never change, although if the plugin
 328  * dies and returns for some reason it may happen.
 329  */
 330 static struct GNUNET_SERVER_NotificationContext *nc;
 331
 332 /**
 333  * Handle for the statistics service.
 334  */
 335 struct GNUNET_STATISTICS_Handle *stats;
 336
 337
 338 /**
 339  * Get distance information from 'atsi'.
 340  *
 341  * @param atsi performance data
 342  * @param atsi_count number of entries in atsi
 343  * @return connected transport distance
 344  */
 345 static uint32_t
 346 get_atsi_distance (const struct GNUNET_ATS_Information *atsi,
 347                    unsigned int atsi_count)
 348 {
 349   unsigned int i;
 350
 351   for (i = 0; i < atsi_count; i++)
 352     if (ntohl (atsi[i].type) == GNUNET_ATS_QUALITY_NET_DISTANCE)
 353       return ntohl (atsi->value);
 354   /* FIXME: we do not have distance data? Assume direct neighbor. */
 355   return DIRECT_NEIGHBOR_COST;
 356 }
 357
 358
 359 /**
 360  * Forward a message from another peer to the plugin.
 361  *
 362  * @param message the message to send to the plugin
 363  * @param origin the original sender of the message
 364  * @param distance distance to the original sender of the message
 365  */
 366 static void
 367 send_data_to_plugin (const struct GNUNET_MessageHeader *message,
 368                      const struct GNUNET_PeerIdentity *origin,
 369                      uint32_t distance)
 370 {
 371   struct GNUNET_DV_ReceivedMessage *received_msg;
 372   size_t size;
 373
 374   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 375               "Delivering message from peer `%s'\n",
 376               GNUNET_i2s (origin));
 377   size = sizeof (struct GNUNET_DV_ReceivedMessage) +
 378     ntohs (message->size);
 379   if (size >= GNUNET_SERVER_MAX_MESSAGE_SIZE)
 380   {
 381     GNUNET_break (0); /* too big */
 382     return;
 383   }
 384   received_msg = GNUNET_malloc (size);
 385   received_msg->header.size = htons (size);
 386   received_msg->header.type = htons (GNUNET_MESSAGE_TYPE_DV_RECV);
 387   received_msg->distance = htonl (distance);
 388   received_msg->sender = *origin;
 389   memcpy (&received_msg[1], message, ntohs (message->size));
 390   GNUNET_SERVER_notification_context_broadcast (nc,
 391                                                 &received_msg->header,
 392                                                 GNUNET_YES);
 393   GNUNET_free (received_msg);
 394 }
 395
 396
 397 /**
 398  * Forward a control message to the plugin.
 399  *
 400  * @param message the message to send to the plugin
 401  */
 402 static void
 403 send_control_to_plugin (const struct GNUNET_MessageHeader *message)
 404 {
 405   GNUNET_SERVER_notification_context_broadcast (nc,
 406                                                 message,
 407                                                 GNUNET_NO);
 408 }
 409
 410
 411 /**
 412  * Give an (N)ACK message to the plugin, we transmitted a message for it.
 413  *
 414  * @param target peer that received the message
 415  * @param uid plugin-chosen UID for the message
 416  * @param nack GNUNET_NO to send ACK, GNUNET_YES to send NACK
 417  */
 418 static void
 419 send_ack_to_plugin (const struct GNUNET_PeerIdentity *target,
 420                     uint32_t uid,
 421                     int nack)
 422 {
 423   struct GNUNET_DV_AckMessage ack_msg;
 424
 425   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 426               "Delivering ACK for message to peer `%s'\n",
 427               GNUNET_i2s (target));
 428   ack_msg.header.size = htons (sizeof (ack_msg));
 429   ack_msg.header.type = htons ((GNUNET_YES == nack)
 430                                ? GNUNET_MESSAGE_TYPE_DV_SEND_NACK
 431                                : GNUNET_MESSAGE_TYPE_DV_SEND_ACK);
 432   ack_msg.uid = htonl (uid);
 433   ack_msg.target = *target;
 434   send_control_to_plugin (&ack_msg.header);
 435 }
 436
 437
 438 /**
 439  * Send a DISTANCE_CHANGED message to the plugin.
 440  *
 441  * @param peer peer with a changed distance
 442  * @param distance new distance to the peer
 443  */
 444 static void
 445 send_distance_change_to_plugin (const struct GNUNET_PeerIdentity *peer,
 446                                 uint32_t distance)
 447 {
 448   struct GNUNET_DV_DistanceUpdateMessage du_msg;
 449
 450   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 451               "Delivering DISTANCE_CHANGED for message about peer `%s'\n",
 452               GNUNET_i2s (peer));
 453   du_msg.header.size = htons (sizeof (du_msg));
 454   du_msg.header.type = htons (GNUNET_MESSAGE_TYPE_DV_DISTANCE_CHANGED);
 455   du_msg.distance = htonl (distance);
 456   du_msg.peer = *peer;
 457   send_control_to_plugin (&du_msg.header);
 458 }
 459
 460
 461 /**
 462  * Give a CONNECT message to the plugin.
 463  *
 464  * @param target peer that connected
 465  * @param distance distance to the target
 466  */
 467 static void
 468 send_connect_to_plugin (const struct GNUNET_PeerIdentity *target,
 469                         uint32_t distance)
 470 {
 471   struct GNUNET_DV_ConnectMessage cm;
 472
 473   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 474               "Delivering CONNECT about peer `%s'\n",
 475               GNUNET_i2s (target));
 476   cm.header.size = htons (sizeof (cm));
 477   cm.header.type = htons (GNUNET_MESSAGE_TYPE_DV_CONNECT);
 478   cm.distance = htonl (distance);
 479   cm.peer = *target;
 480   send_control_to_plugin (&cm.header);
 481 }
 482
 483
 484 /**
 485  * Give a DISCONNECT message to the plugin.
 486  *
 487  * @param target peer that disconnected
 488  */
 489 static void
 490 send_disconnect_to_plugin (const struct GNUNET_PeerIdentity *target)
 491 {
 492   struct GNUNET_DV_DisconnectMessage dm;
 493
 494   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 495               "Delivering DISCONNECT about peer `%s'\n",
 496               GNUNET_i2s (target));
 497   dm.header.size = htons (sizeof (dm));
 498   dm.header.type = htons (GNUNET_MESSAGE_TYPE_DV_DISCONNECT);
 499   dm.reserved = htonl (0);
 500   dm.peer = *target;
 501   send_control_to_plugin (&dm.header);
 502 }
 503
 504
 505 /**
 506  * Function called to transfer a message to another peer
 507  * via core.
 508  *
 509  * @param cls closure with the direct neighbor
 510  * @param size number of bytes available in buf
 511  * @param buf where the callee should write the message
 512  * @return number of bytes written to buf
 513  */
 514 static size_t
 515 core_transmit_notify (void *cls, size_t size, void *buf)
 516 {
 517   struct DirectNeighbor *dn = cls;
 518   char *cbuf = buf;
 519   struct PendingMessage *pending;
 520   size_t off;
 521   size_t msize;
 522
 523   dn->cth = NULL;
 524   if (NULL == buf)
 525   {
 526     /* peer disconnected */
 527     return 0;
 528   }
 529   off = 0;
 530   pending = dn->pm_head;
 531   off = 0;
 532   while ( (NULL != (pending = dn->pm_head)) &&
 533           (size >= off + (msize = ntohs (pending->msg->size))))
 534   {
 535     dn->pm_queue_size--;
 536     GNUNET_CONTAINER_DLL_remove (dn->pm_head,
 537                                  dn->pm_tail,
 538                                  pending);
 539     memcpy (&cbuf[off], pending->msg, msize);
 540     if (0 != pending->uid)
 541       send_ack_to_plugin (&pending->ultimate_target,
 542                           pending->uid,
 543                           GNUNET_NO);
 544     GNUNET_free (pending);
 545     off += msize;
 546   }
 547   if (NULL != dn->pm_head)
 548     dn->cth =
 549       GNUNET_CORE_notify_transmit_ready (core_api,
 550                                          GNUNET_YES /* cork */,
 551                                          0 /* priority */,
 552                                          GNUNET_TIME_UNIT_FOREVER_REL,
 553                                          &dn->peer,
 554                                          msize,
 555                                          &core_transmit_notify, dn);
 556   return off;
 557 }
 558
 559
 560 /**
 561  * Forward the given payload to the given target.
 562  *
 563  * @param target where to send the message
 564  * @param uid unique ID for the message
 565  * @param ultimate_target ultimate recipient for the message
 566  * @param distance expected (remaining) distance to the target
 567  * @param sender original sender of the message
 568  * @param payload payload of the message
 569  */
 570 static void
 571 forward_payload (struct DirectNeighbor *target,
 572                  uint32_t distance,
 573                  uint32_t uid,
 574                  const struct GNUNET_PeerIdentity *sender,
 575                  const struct GNUNET_PeerIdentity *ultimate_target,
 576                  const struct GNUNET_MessageHeader *payload)
 577 {
 578   struct PendingMessage *pm;
 579   struct RouteMessage *rm;
 580   size_t msize;
 581
 582   if ( (target->pm_queue_size >= MAX_QUEUE_SIZE) &&
 583        (0 != memcmp (sender,
 584                      &my_identity,
 585                      sizeof (struct GNUNET_PeerIdentity))) )
 586   {
 587     GNUNET_break (0 == uid);
 588     return;
 589   }
 590   msize = sizeof (struct RouteMessage) + ntohs (payload->size);
 591   if (msize >= GNUNET_SERVER_MAX_MESSAGE_SIZE)
 592   {
 593     GNUNET_break (0);
 594     return;
 595   }
 596   pm = GNUNET_malloc (sizeof (struct PendingMessage) + msize);
 597   pm->ultimate_target = *ultimate_target;
 598   pm->uid = uid;
 599   pm->msg = (const struct GNUNET_MessageHeader *) &pm[1];
 600   rm = (struct RouteMessage *) &pm[1];
 601   rm->header.size = htons ((uint16_t) msize);
 602   rm->header.type = htons (GNUNET_MESSAGE_TYPE_DV_ROUTE);
 603   rm->distance = htonl (distance);
 604   rm->target = target->peer;
 605   rm->sender = *sender;
 606   memcpy (&rm[1], payload, ntohs (payload->size));
 607   GNUNET_CONTAINER_DLL_insert_tail (target->pm_head,
 608                                     target->pm_tail,
 609                                     pm);
 610   target->pm_queue_size++;
 611   if (NULL == target->cth)
 612     target->cth = GNUNET_CORE_notify_transmit_ready (core_api,
 613                                                      GNUNET_YES /* cork */,
 614                                                      0 /* priority */,
 615                                                      GNUNET_TIME_UNIT_FOREVER_REL,
 616                                                      &target->peer,
 617                                                      msize,
 618                                                      &core_transmit_notify, target);
 619 }
 620
 621
 622 /**
 623  * Find a free slot for storing a 'route' in the 'consensi'
 624  * set at the given distance.
 625  *
 626  * @param distance distance to use for the set slot
 627  */
 628 static unsigned int
 629 get_consensus_slot (uint32_t distance)
 630 {
 631   struct ConsensusSet *cs;
 632   unsigned int i;
 633
 634   cs = &consensi[distance];
 635   i = 0;
 636   while ( (i < cs->array_length) &&
 637           (NULL != cs->targets[i]) ) i++;
 638   if (i == cs->array_length)
 639     GNUNET_array_grow (cs->targets,
 640                        cs->array_length,
 641                        cs->array_length * 2 + 2);
 642   return i;
 643 }
 644
 645
 646 /**
 647  * Allocate a slot in the consensus set for a route.
 648  *
 649  * @param route route to initialize
 650  * @param distance which consensus set to use
 651  */
 652 static void
 653 allocate_route (struct Route *route,
 654                 uint32_t distance)
 655 {
 656   unsigned int i;
 657
 658   i = get_consensus_slot (distance);
 659   route->set_offset = i;
 660   consensi[distance].targets[i] = route;
 661   route->target.distance = htonl (distance);
 662 }
 663
 664
 665 /**
 666  * Release a slot in the consensus set for a route.
 667  *
 668  * @param route route to release the slot from
 669  */
 670 static void
 671 release_route (struct Route *route)
 672 {
 673   consensi[ntohl (route->target.distance)].targets[route->set_offset] = NULL;
 674   route->set_offset = UINT_MAX; /* indicate invalid slot */
 675 }
 676
 677
 678 /**
 679  * Move a route from one consensus set to another.
 680  *
 681  * @param route route to move
 682  * @param new_distance new distance for the route (destination set)
 683  */
 684 static void
 685 move_route (struct Route *route,
 686             uint32_t new_distance)
 687 {
 688   unsigned int i;
 689
 690   release_route (route);
 691   i = get_consensus_slot (new_distance);
 692   route->set_offset = i;
 693   consensi[new_distance].targets[i] = route;
 694   route->target.distance = htonl (new_distance);
 695 }
 696
 697
 698 /**
 699  * Start creating a new consensus from scratch.
 700  *
 701  * @param cls the 'struct DirectNeighbor' of the peer we're building
 702  *        a routing consensus with
 703  * @param tc scheduler context
 704  */
 705 static void
 706 start_consensus (void *cls,
 707                  const struct GNUNET_SCHEDULER_TaskContext *tc);
 708
 709
 710 /**
 711  * Method called whenever a peer connects.
 712  *
 713  * @param cls closure
 714  * @param peer peer identity this notification is about
 715  * @param atsi performance data
 716  * @param atsi_count number of entries in atsi
 717  */
 718 static void
 719 handle_core_connect (void *cls, const struct GNUNET_PeerIdentity *peer,
 720                      const struct GNUNET_ATS_Information *atsi,
 721                      unsigned int atsi_count)
 722 {
 723   struct DirectNeighbor *neighbor;
 724   struct Route *route;
 725   uint32_t distance;
 726
 727   /* Check for connect to self message */
 728   if (0 == memcmp (&my_identity, peer, sizeof (struct GNUNET_PeerIdentity)))
 729     return;
 730   distance = get_atsi_distance (atsi, atsi_count);
 731   neighbor = GNUNET_CONTAINER_multihashmap_get (direct_neighbors,
 732                                                 &peer->hashPubKey);
 733   if (NULL != neighbor)
 734   {
 735     GNUNET_break (0);
 736     return;
 737   }
 738   if (DIRECT_NEIGHBOR_COST != distance)
 739     return; /* is a DV-neighbor */
 740   GNUNET_STATISTICS_update (stats,
 741                             "# peers connected (1-hop)",
 742                             1, GNUNET_NO);
 743   neighbor = GNUNET_malloc (sizeof (struct DirectNeighbor));
 744   neighbor->peer = *peer;
 745   GNUNET_assert (GNUNET_YES ==
 746                  GNUNET_CONTAINER_multihashmap_put (direct_neighbors,
 747                                                     &peer->hashPubKey,
 748                                                     neighbor,
 749                                                     GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
 750   route = GNUNET_CONTAINER_multihashmap_get (all_routes,
 751                                              &peer->hashPubKey);
 752   if (NULL != route)
 753   {
 754     send_disconnect_to_plugin (peer);
 755     release_route (route);
 756     GNUNET_free (route);
 757   }
 758   neighbor->consensus_task = GNUNET_SCHEDULER_add_now (&start_consensus,
 759                                                        neighbor);
 760 }
 761
 762
 763 /**
 764  * Called for each 'target' in a neighbor table to free the associated memory.
 765  *
 766  * @param cls NULL
 767  * @param key key of the value
 768  * @param value value to free
 769  * @return GNUNET_OK to continue to iterate
 770  */
 771 static int
 772 free_targets (void *cls,
 773               const struct GNUNET_HashCode *key,
 774               void *value)
 775 {
 776   GNUNET_free (value);
 777   return GNUNET_OK;
 778 }
 779
 780
 781 /**
 782  * Multihashmap iterator for checking if a given route is
 783  * (now) useful to this peer.
 784  *
 785  * @param cls the direct neighbor for the given route
 786  * @param key key value stored under
 787  * @param value a 'struct Target' that may or may not be useful; not that
 788  *        the distance in 'target' does not include the first hop yet
 789  * @return GNUNET_YES to continue iteration, GNUNET_NO to stop
 790  */
 791 static int
 792 check_possible_route (void *cls, const struct GNUNET_HashCode * key, void *value)
 793 {
 794   struct DirectNeighbor *neighbor = cls;
 795   struct Target *target = value;
 796   struct Route *route;
 797
 798   route = GNUNET_CONTAINER_multihashmap_get (all_routes,
 799                                            key);
 800   if (NULL != route)
 801   {
 802     if (ntohl (route->target.distance) > ntohl (target->distance) + 1)
 803     {
 804       /* this 'target' is cheaper than the existing route; switch to alternative route! */
 805       move_route (route, ntohl (target->distance) + 1);
 806       route->next_hop = neighbor;
 807       send_distance_change_to_plugin (&target->peer, ntohl (target->distance) + 1);
 808     }
 809     return GNUNET_YES; /* got a route to this target already */
 810   }
 811   route = GNUNET_malloc (sizeof (struct Route));
 812   route->next_hop = neighbor;
 813   route->target.distance = htonl (ntohl (target->distance) + 1);
 814   route->target.peer = target->peer;
 815   allocate_route (route, ntohl (route->target.distance));
 816   GNUNET_assert (GNUNET_YES ==
 817                  GNUNET_CONTAINER_multihashmap_put (all_routes,
 818                                                     &route->target.peer.hashPubKey,
 819                                                     route,
 820                                                     GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
 821   send_connect_to_plugin (&route->target.peer, ntohl (target->distance));
 822   return GNUNET_YES;
 823 }
 824
 825
 826 /**
 827  * Multihashmap iterator for finding routes that were previously
 828  * "hidden" due to a better route (called after a disconnect event).
 829  *
 830  * @param cls NULL
 831  * @param key peer identity of the given direct neighbor
 832  * @param value a 'struct DirectNeighbor' to check for additional routes
 833  * @return GNUNET_YES to continue iteration
 834  */
 835 static int
 836 refresh_routes (void *cls, const struct GNUNET_HashCode * key, void *value)
 837 {
 838   struct DirectNeighbor *neighbor = value;
 839
 840   if (NULL != neighbor->neighbor_table)
 841     GNUNET_CONTAINER_multihashmap_iterate (neighbor->neighbor_table,
 842                                            &check_possible_route,
 843                                            neighbor);
 844   return GNUNET_YES;
 845 }
 846
 847
 848 /**
 849  * Check if a target was removed from the set of the other peer; if so,
 850  * if we also used it for our route, we need to remove it from our
 851  * 'all_routes' set (and later check if an alternative path now exists).
 852  *
 853  * @param cls the 'struct DirectNeighbor'
 854  * @param key peer identity for the target
 855  * @param value a 'struct Target' previously reachable via the given neighbor
 856  */
 857 static int
 858 check_target_removed (void *cls,
 859                       const struct GNUNET_HashCode *key,
 860                       void *value)
 861 {
 862   struct DirectNeighbor *neighbor = cls;
 863   struct Target *new_target;
 864   struct Route *current_route;
 865
 866   new_target = GNUNET_CONTAINER_multihashmap_get (neighbor->neighbor_table_consensus,
 867                                                   key);
 868   if (NULL == new_target)
 869   {
 870     /* target was revoked, check if it was used */
 871     current_route = GNUNET_CONTAINER_multihashmap_get (all_routes,
 872                                                        key);
 873     if ( (NULL == current_route) ||
 874          (current_route->next_hop != neighbor) )
 875     {
 876       /* didn't matter, wasn't used */
 877       return GNUNET_OK;
 878     }
 879     /* remove existing route */
 880     GNUNET_assert (GNUNET_YES ==
 881                    GNUNET_CONTAINER_multihashmap_remove (all_routes, key, current_route));
 882     send_disconnect_to_plugin (&current_route->target.peer);
 883     GNUNET_free (current_route);
 884     neighbor->target_removed = GNUNET_YES;
 885     return GNUNET_OK;
 886   }
 887   return GNUNET_OK;
 888 }
 889
 890
 891 /**
 892  * Check if a target was added to the set of the other peer; if it
 893  * was added or impoves the existing route, do the needed updates.
 894  *
 895  * @param cls the 'struct DirectNeighbor'
 896  * @param key peer identity for the target
 897  * @param value a 'struct Target' now reachable via the given neighbor
 898  */
 899 static int
 900 check_target_added (void *cls,
 901                       const struct GNUNET_HashCode *key,
 902                       void *value)
 903 {
 904   struct DirectNeighbor *neighbor = cls;
 905   struct Target *target = value;
 906   struct Route *current_route;
 907
 908   /* target was revoked, check if it was used */
 909   current_route = GNUNET_CONTAINER_multihashmap_get (all_routes,
 910                                                      key);
 911   if (NULL != current_route)
 912   {
 913     /* route exists */
 914     if (current_route->next_hop == neighbor)
 915     {
 916       /* we had the same route before, no change */
 917       if (ntohl (target->distance) + 1 != ntohl (current_route->target.distance))
 918       {
 919         current_route->target.distance = htonl (ntohl (target->distance) + 1);
 920         send_distance_change_to_plugin (&target->peer, ntohl (target->distance) + 1);
 921       }
 922       return GNUNET_OK;
 923     }
 924     if (ntohl (current_route->target.distance) >= ntohl (target->distance) + 1)
 925     {
 926       /* alternative, shorter route exists, ignore */
 927       return GNUNET_OK;
 928     }
 929     /* new route is better than the existing one, take over! */
 930     /* NOTE: minor security issue: malicious peers may advertise
 931        very short routes to take over longer paths; as we don't
 932        check that the shorter routes actually work, a malicious
 933        direct neighbor can use this to DoS our long routes */
 934     current_route->next_hop = neighbor;
 935     current_route->target.distance = htonl (ntohl (target->distance) + 1);
 936     send_distance_change_to_plugin (&target->peer, ntohl (target->distance) + 1);
 937     return GNUNET_OK;
 938   }
 939   /* new route */
 940   current_route = GNUNET_malloc (sizeof (struct Route));
 941   current_route->next_hop = neighbor;
 942   current_route->target.peer = target->peer;
 943   current_route->target.distance = htonl (ntohl (target->distance) + 1);
 944   GNUNET_assert (GNUNET_YES ==
 945                  GNUNET_CONTAINER_multihashmap_put (all_routes,
 946                                                     &current_route->target.peer.hashPubKey,
 947                                                     current_route,
 948                                                     GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
 949   send_connect_to_plugin (&current_route->target.peer,
 950                           ntohl (current_route->target.distance));
 951   return GNUNET_OK;
 952 }
 953
 954
 955
 956 /**
 957  * The consensus has concluded, clean up and schedule the next one.
 958  *
 959  * @param cls the 'struct GNUNET_DirectNeighbor' with which we created the consensus
 960  * @param group FIXME
 961  */
 962 static void
 963 consensus_done_cb (void *cls)
 964 {
 965   struct DirectNeighbor *neighbor = cls;
 966
 967   GNUNET_CONSENSUS_destroy (neighbor->consensus);
 968   neighbor->consensus = NULL;
 969   /* remove targets that disappeared */
 970   neighbor->target_removed = GNUNET_NO;
 971   GNUNET_CONTAINER_multihashmap_iterate (neighbor->neighbor_table,
 972                                          &check_target_removed,
 973                                          neighbor);
 974   if (GNUNET_YES == neighbor->target_removed)
 975   {
 976     /* check if we got an alternative for the removed routes */
 977     GNUNET_CONTAINER_multihashmap_iterate (direct_neighbors,
 978                                            &refresh_routes,
 979                                            NULL);
 980   }
 981   /* add targets that appeared (and check for improved routes) */
 982   GNUNET_CONTAINER_multihashmap_iterate (neighbor->neighbor_table_consensus,
 983                                          &check_target_added,
 984                                          neighbor);
 985   if (NULL != neighbor->neighbor_table)
 986   {
 987     GNUNET_CONTAINER_multihashmap_iterate (neighbor->neighbor_table,
 988                                            &free_targets,
 989                                            NULL);
 990     GNUNET_CONTAINER_multihashmap_destroy (neighbor->neighbor_table);
 991     neighbor->neighbor_table = NULL;
 992   }
 993   neighbor->neighbor_table = neighbor->neighbor_table_consensus;
 994   neighbor->neighbor_table_consensus = NULL;
 995   neighbor->consensus_task = GNUNET_SCHEDULER_add_delayed (GNUNET_DV_CONSENSUS_FREQUENCY,
 996                                                            &start_consensus,
 997                                                            neighbor);
 998 }
 999
1000
1001 /**
1002  * We inserted the last element into the consensus, get ready to
1003  * insert the next element into the consensus or conclude if
1004  * we're done.
1005  *
1006  * @param cls the 'struct DirectNeighbor' of the peer we're building
1007  *        a routing consensus with
1008  * @param success GNUNET_OK if the last element was added successfully,
1009  *                GNUNET_SYSERR if we failed
1010  */
1011 static void
1012 insert_next_element (void *cls,
1013                      int success)
1014 {
1015   struct DirectNeighbor *neighbor = cls;
1016   struct GNUNET_CONSENSUS_Element element;
1017
1018   while ( (DEFAULT_FISHEYE_DEPTH - 1 > neighbor->consensus_insertion_distance) &&
1019           (consensi[neighbor->consensus_insertion_distance].array_length == neighbor->consensus_insertion_offset) )
1020   {
1021     neighbor->consensus_insertion_offset = 0;
1022     neighbor->consensus_insertion_distance++;
1023     /* skip over NULL entries */
1024     while ( (DEFAULT_FISHEYE_DEPTH - 1 > neighbor->consensus_insertion_distance) &&
1025             (consensi[neighbor->consensus_insertion_distance].array_length < neighbor->consensus_insertion_offset) &&
1026             (NULL == consensi[neighbor->consensus_insertion_distance].targets[neighbor->consensus_insertion_offset]) )
1027       neighbor->consensus_insertion_offset++;
1028   }
1029   if (DEFAULT_FISHEYE_DEPTH - 1 == neighbor->consensus_insertion_distance)
1030   {
1031     /* we're done, conclude! */
1032     GNUNET_CONSENSUS_conclude (neighbor->consensus,
1033                                GNUNET_DV_CONSENSUS_FREQUENCY,
1034                                &consensus_done_cb,
1035                                neighbor);
1036     return;
1037   }
1038   element.size = sizeof (struct Target);
1039   element.data = &consensi[neighbor->consensus_insertion_distance].targets[neighbor->consensus_insertion_offset++]->target;
1040
1041   /* skip over NULL entries */
1042   while ( (DEFAULT_FISHEYE_DEPTH - 1 > neighbor->consensus_insertion_distance) &&
1043           (consensi[neighbor->consensus_insertion_distance].array_length < neighbor->consensus_insertion_offset) &&
1044           (NULL == consensi[neighbor->consensus_insertion_distance].targets[neighbor->consensus_insertion_offset]) )
1045     neighbor->consensus_insertion_offset++;
1046   GNUNET_CONSENSUS_insert (neighbor->consensus,
1047                            &element,
1048                            &insert_next_element,
1049                            neighbor);
1050 }
1051
1052
1053 /**
1054  * We have learned a new route from the other peer.  Add it to the
1055  * route set we're building.
1056  *
1057  * @param cls the 'struct DirectNeighbor' we're building the consensus with
1058  * @param element the new element we have learned
1059  * @return GNUNET_OK if the valid is well-formed and should be added to the consensus,
1060  *         GNUNET_SYSERR if the element should be ignored and not be propagated
1061  */
1062 static int
1063 learn_route_cb (void *cls,
1064                 const struct GNUNET_CONSENSUS_Element *element)
1065 {
1066   struct DirectNeighbor *neighbor = cls;
1067   struct Target *target;
1068
1069   if (NULL == element)
1070   {
1071     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
1072                 "Failed to establish DV consensus, will try again later\n");
1073     GNUNET_CONSENSUS_destroy (neighbor->consensus);
1074     if (NULL != neighbor->neighbor_table_consensus)
1075     {
1076       GNUNET_CONTAINER_multihashmap_iterate (neighbor->neighbor_table_consensus,
1077                                              &free_targets,
1078                                              NULL);
1079       GNUNET_CONTAINER_multihashmap_destroy (neighbor->neighbor_table_consensus);
1080       neighbor->neighbor_table_consensus = NULL;
1081     }
1082     neighbor->consensus = NULL;
1083     neighbor->consensus_task = GNUNET_SCHEDULER_add_delayed (GNUNET_DV_CONSENSUS_FREQUENCY,
1084                                                              &start_consensus,
1085                                                              neighbor);
1086     return GNUNET_SYSERR;
1087   }
1088   if (sizeof (struct Target) != element->size)
1089   {
1090     GNUNET_break_op (0);
1091     return GNUNET_SYSERR;
1092   }
1093   target = GNUNET_malloc (sizeof (struct Target));
1094   memcpy (target, element->data, sizeof (struct Target));
1095   if (GNUNET_YES !=
1096       GNUNET_CONTAINER_multihashmap_put (neighbor->neighbor_table_consensus,
1097                                          &target->peer.hashPubKey,
1098                                          target,
1099                                          GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY))
1100   {
1101     GNUNET_break_op (0);
1102     GNUNET_free (target);
1103     return GNUNET_SYSERR;
1104   }
1105   return GNUNET_OK;
1106 }
1107
1108
1109 /**
1110  * Start creating a new consensus from scratch.
1111  *
1112  * @param cls the 'struct DirectNeighbor' of the peer we're building
1113  *        a routing consensus with
1114  * @param tc scheduler context
1115  */
1116 static void
1117 start_consensus (void *cls,
1118                  const struct GNUNET_SCHEDULER_TaskContext *tc)
1119 {
1120   struct DirectNeighbor *neighbor = cls;
1121   struct GNUNET_HashCode session_id;
1122   struct GNUNET_HashCode real_session_id;
1123
1124   neighbor->consensus_task = GNUNET_SCHEDULER_NO_TASK;
1125   neighbor->consensus_insertion_offset = 0;
1126   neighbor->consensus_insertion_distance = 0;
1127   GNUNET_assert (NULL == neighbor->neighbor_table_consensus);
1128   GNUNET_assert (NULL == neighbor->consensus);
1129   neighbor->neighbor_table_consensus = GNUNET_CONTAINER_multihashmap_create (1024, GNUNET_YES);
1130   /* construct session ID seed as XOR of both peer's identities */
1131   GNUNET_CRYPTO_hash_xor (&my_identity.hashPubKey,
1132                           &neighbor->peer.hashPubKey,
1133                           &session_id);
1134   /* make sure session ID is unique across applications by salting it with 'DV' */
1135   GNUNET_CRYPTO_hkdf (&real_session_id, sizeof (real_session_id),
1136                       GCRY_MD_SHA512, GCRY_MD_SHA256,
1137                       "DV-SALT", 2,
1138                       &session_id, sizeof (session_id),
1139                       NULL, 0);
1140   neighbor->consensus = GNUNET_CONSENSUS_create (cfg,
1141                                                  1,
1142                                                  &neighbor->peer,
1143                                                  &real_session_id,
1144                                                  &learn_route_cb,
1145                                                  neighbor);
1146   if (NULL == neighbor->consensus)
1147   {
1148     neighbor->consensus_task = GNUNET_SCHEDULER_add_delayed (GNUNET_DV_CONSENSUS_FREQUENCY,
1149                                                              &start_consensus,
1150                                                              neighbor);
1151     return;
1152   }
1153   insert_next_element (neighbor, GNUNET_OK);
1154 }
1155
1156
1157 /**
1158  * Core handler for DV data messages.  Whatever this message
1159  * contains all we really have to do is rip it out of its
1160  * DV layering and give it to our pal the DV plugin to report
1161  * in with.
1162  *
1163  * @param cls closure
1164  * @param peer peer which sent the message (immediate sender)
1165  * @param message the message
1166  * @param atsi transport ATS information (latency, distance, etc.)
1167  * @param atsi_count number of entries in atsi
1168  * @return GNUNET_OK on success, GNUNET_SYSERR if the other peer violated the protocol
1169  */
1170 static int
1171 handle_dv_route_message (void *cls, const struct GNUNET_PeerIdentity *peer,
1172                          const struct GNUNET_MessageHeader *message,
1173                          const struct GNUNET_ATS_Information *atsi,
1174                          unsigned int atsi_count)
1175 {
1176   const struct RouteMessage *rm;
1177   const struct GNUNET_MessageHeader *payload;
1178   struct Route *route;
1179
1180   if (ntohs (message->size) < sizeof (struct RouteMessage) + sizeof (struct GNUNET_MessageHeader))
1181   {
1182     GNUNET_break_op (0);
1183     return GNUNET_SYSERR;
1184   }
1185   rm = (const struct RouteMessage *) message;
1186   payload = (const struct GNUNET_MessageHeader *) &rm[1];
1187   if (ntohs (message->size) != sizeof (struct RouteMessage) + ntohs (payload->size))
1188   {
1189     GNUNET_break_op (0);
1190     return GNUNET_SYSERR;
1191   }
1192   if (0 == memcmp (&rm->target,
1193                    &my_identity,
1194                    sizeof (struct GNUNET_PeerIdentity)))
1195   {
1196     /* message is for me, check reverse route! */
1197     route = GNUNET_CONTAINER_multihashmap_get (all_routes,
1198                                                &rm->sender.hashPubKey);
1199     if (NULL == route)
1200     {
1201       /* don't have reverse route, drop */
1202       GNUNET_STATISTICS_update (stats,
1203                                 "# message discarded (no reverse route)",
1204                                 1, GNUNET_NO);
1205       return GNUNET_OK;
1206     }
1207     send_data_to_plugin (payload,
1208                          &rm->sender,
1209                          ntohl (route->target.distance));
1210     return GNUNET_OK;
1211   }
1212   route = GNUNET_CONTAINER_multihashmap_get (all_routes,
1213                                              &rm->target.hashPubKey);
1214   if (NULL == route)
1215   {
1216     GNUNET_STATISTICS_update (stats,
1217                               "# messages discarded (no route)",
1218                               1, GNUNET_NO);
1219     return GNUNET_OK;
1220   }
1221   if (ntohl (route->target.distance) > ntohl (rm->distance) + 1)
1222   {
1223     GNUNET_STATISTICS_update (stats,
1224                               "# messages discarded (target too far)",
1225                               1, GNUNET_NO);
1226     return GNUNET_OK;
1227   }
1228   forward_payload (route->next_hop,
1229                    ntohl (route->target.distance),
1230                    0,
1231                    &rm->target,
1232                    &rm->sender,
1233                    payload);
1234   return GNUNET_OK;
1235 }
1236
1237
1238 /**
1239  * Service server's handler for message send requests (which come
1240  * bubbling up to us through the DV plugin).
1241  *
1242  * @param cls closure
1243  * @param client identification of the client
1244  * @param message the actual message
1245  */
1246 static void
1247 handle_dv_send_message (void *cls, struct GNUNET_SERVER_Client *client,
1248                         const struct GNUNET_MessageHeader *message)
1249 {
1250   struct Route *route;
1251   const struct GNUNET_DV_SendMessage *msg;
1252   const struct GNUNET_MessageHeader *payload;
1253
1254   if (ntohs (message->size) < sizeof (struct GNUNET_DV_SendMessage) + sizeof (struct GNUNET_MessageHeader))
1255   {
1256     GNUNET_break (0);
1257     GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
1258     return;
1259   }
1260   msg = (const struct GNUNET_DV_SendMessage *) message;
1261   GNUNET_break (0 != ntohl (msg->uid));
1262   payload = (const struct GNUNET_MessageHeader *) &msg[1];
1263   if (ntohs (message->size) != sizeof (struct GNUNET_DV_SendMessage) + ntohs (payload->size))
1264   {
1265     GNUNET_break (0);
1266     GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
1267     return;
1268   }
1269   route = GNUNET_CONTAINER_multihashmap_get (all_routes,
1270                                              &msg->target.hashPubKey);
1271   if (NULL == route)
1272   {
1273     /* got disconnected */
1274     GNUNET_STATISTICS_update (stats,
1275                               "# local messages discarded (no route)",
1276                               1, GNUNET_NO);
1277     send_ack_to_plugin (&msg->target, ntohl (msg->uid), GNUNET_YES);
1278     GNUNET_SERVER_receive_done (client, GNUNET_OK);
1279     return;
1280   }
1281   forward_payload (route->next_hop,
1282                    ntohl (route->target.distance),
1283                    htonl (msg->uid),
1284                    &msg->target,
1285                    &my_identity,
1286                    payload);
1287   GNUNET_SERVER_receive_done (client, GNUNET_OK);
1288 }
1289
1290
1291 /**
1292  * Multihashmap iterator for freeing routes that go via a particular
1293  * neighbor that disconnected and is thus no longer available.
1294  *
1295  * @param cls the direct neighbor that is now unavailable
1296  * @param key key value stored under
1297  * @param value a 'struct Route' that may or may not go via neighbor
1298  *
1299  * @return GNUNET_YES to continue iteration, GNUNET_NO to stop
1300  */
1301 static int
1302 cull_routes (void *cls, const struct GNUNET_HashCode * key, void *value)
1303 {
1304   struct DirectNeighbor *neighbor = cls;
1305   struct Route *route = value;
1306
1307   if (route->next_hop != neighbor)
1308     return GNUNET_YES; /* not affected */
1309   GNUNET_assert (GNUNET_YES ==
1310                  GNUNET_CONTAINER_multihashmap_remove (all_routes, key, value));
1311   release_route (route);
1312   send_disconnect_to_plugin (&route->target.peer);
1313   GNUNET_free (route);
1314   return GNUNET_YES;
1315 }
1316
1317
1318 /**
1319  * Cleanup all of the data structures associated with a given neighbor.
1320  *
1321  * @param neighbor neighbor to clean up
1322  */
1323 static void
1324 cleanup_neighbor (struct DirectNeighbor *neighbor)
1325 {
1326   struct PendingMessage *pending;
1327
1328   while (NULL != (pending = neighbor->pm_head))
1329   {
1330     neighbor->pm_queue_size--;
1331     GNUNET_CONTAINER_DLL_remove (neighbor->pm_head,
1332                                  neighbor->pm_tail,
1333                                  pending);
1334     GNUNET_free (pending);
1335   }
1336   GNUNET_CONTAINER_multihashmap_iterate (all_routes,
1337                                          &cull_routes,
1338                                          neighbor);
1339   if (NULL != neighbor->cth)
1340   {
1341     GNUNET_CORE_notify_transmit_ready_cancel (neighbor->cth);
1342     neighbor->cth = NULL;
1343   }
1344   if (NULL != neighbor->neighbor_table_consensus)
1345   {
1346     GNUNET_CONTAINER_multihashmap_iterate (neighbor->neighbor_table_consensus,
1347                                            &free_targets,
1348                                            NULL);
1349     GNUNET_CONTAINER_multihashmap_destroy (neighbor->neighbor_table_consensus);
1350     neighbor->neighbor_table_consensus = NULL;
1351   }
1352   if (NULL != neighbor->neighbor_table)
1353   {
1354     GNUNET_CONTAINER_multihashmap_iterate (neighbor->neighbor_table,
1355                                            &free_targets,
1356                                            NULL);
1357     GNUNET_CONTAINER_multihashmap_destroy (neighbor->neighbor_table);
1358     neighbor->neighbor_table = NULL;
1359   }
1360   if (GNUNET_SCHEDULER_NO_TASK != neighbor->consensus_task)
1361   {
1362     GNUNET_SCHEDULER_cancel (neighbor->consensus_task);
1363     neighbor->consensus_task = GNUNET_SCHEDULER_NO_TASK;
1364   }
1365   if (NULL != neighbor->consensus)
1366   {
1367     GNUNET_CONSENSUS_destroy (neighbor->consensus);
1368     neighbor->consensus = NULL;
1369   }
1370   GNUNET_assert (GNUNET_YES ==
1371                  GNUNET_CONTAINER_multihashmap_remove (direct_neighbors,
1372                                                        &neighbor->peer.hashPubKey,
1373                                                        neighbor));
1374   GNUNET_free (neighbor);
1375 }
1376
1377
1378 /**
1379  * Method called whenever a given peer disconnects.
1380  *
1381  * @param cls closure
1382  * @param peer peer identity this notification is about
1383  */
1384 static void
1385 handle_core_disconnect (void *cls, const struct GNUNET_PeerIdentity *peer)
1386 {
1387   struct DirectNeighbor *neighbor;
1388
1389   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1390               "Received core peer disconnect message for peer `%s'!\n",
1391               GNUNET_i2s (peer));
1392   /* Check for disconnect from self message */
1393   if (0 == memcmp (&my_identity, peer, sizeof (struct GNUNET_PeerIdentity)))
1394     return;
1395   neighbor =
1396       GNUNET_CONTAINER_multihashmap_get (direct_neighbors, &peer->hashPubKey);
1397   if (NULL == neighbor)
1398   {
1399     /* must have been a DV-neighbor, ignore */
1400     return;
1401   }
1402   GNUNET_STATISTICS_update (stats,
1403                             "# peers connected (1-hop)",
1404                             -1, GNUNET_NO);
1405   cleanup_neighbor (neighbor);
1406   GNUNET_CONTAINER_multihashmap_iterate (direct_neighbors,
1407                                          &refresh_routes,
1408                                          NULL);
1409 }
1410
1411
1412 /**
1413  * Multihashmap iterator for freeing routes.  Should never be called.
1414  *
1415  * @param cls NULL
1416  * @param key key value stored under
1417  * @param value the route to be freed
1418  *
1419  * @return GNUNET_YES to continue iteration, GNUNET_NO to stop
1420  */
1421 static int
1422 free_route (void *cls, const struct GNUNET_HashCode * key, void *value)
1423 {
1424   struct Route *route = value;
1425
1426   GNUNET_break (0);
1427   GNUNET_assert (GNUNET_YES ==
1428                  GNUNET_CONTAINER_multihashmap_remove (all_routes, key, value));
1429   release_route (route);
1430   send_disconnect_to_plugin (&route->target.peer);
1431   GNUNET_free (route);
1432   return GNUNET_YES;
1433 }
1434
1435
1436 /**
1437  * Multihashmap iterator for freeing direct neighbors. Should never be called.
1438  *
1439  * @param cls NULL
1440  * @param key key value stored under
1441  * @param value the direct neighbor to be freed
1442  *
1443  * @return GNUNET_YES to continue iteration, GNUNET_NO to stop
1444  */
1445 static int
1446 free_direct_neighbors (void *cls, const struct GNUNET_HashCode * key, void *value)
1447 {
1448   struct DirectNeighbor *neighbor = value;
1449
1450   GNUNET_break (0);
1451   cleanup_neighbor (neighbor);
1452   return GNUNET_YES;
1453 }
1454
1455
1456 /**
1457  * Task run during shutdown.
1458  *
1459  * @param cls unused
1460  * @param tc unused
1461  */
1462 static void
1463 shutdown_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
1464 {
1465   unsigned int i;
1466
1467   GNUNET_CORE_disconnect (core_api);
1468   core_api = NULL;
1469   GNUNET_CONTAINER_multihashmap_iterate (direct_neighbors,
1470                                          &free_direct_neighbors, NULL);
1471   GNUNET_CONTAINER_multihashmap_iterate (all_routes,
1472                                          &free_route, NULL);
1473   GNUNET_CONTAINER_multihashmap_destroy (direct_neighbors);
1474   GNUNET_CONTAINER_multihashmap_destroy (all_routes);
1475   GNUNET_STATISTICS_destroy (stats, GNUNET_NO);
1476   stats = NULL;
1477   GNUNET_SERVER_notification_context_destroy (nc);
1478   nc = NULL;
1479   for (i=0;i<DEFAULT_FISHEYE_DEPTH - 1;i++)
1480     GNUNET_array_grow (consensi[i].targets,
1481                        consensi[i].array_length,
1482                        0);
1483 }
1484
1485
1486 /**
1487  * Notify newly connected client about an existing route.
1488  *
1489  * @param cls the 'struct GNUNET_SERVER_Client'
1490  * @param key peer identity
1491  * @param value the XXX.
1492  * @return GNUNET_OK (continue to iterate)
1493  */
1494 static int
1495 add_route (void *cls,
1496            const struct GNUNET_HashCode *key,
1497            void *value)
1498 {
1499   struct GNUNET_SERVER_Client *client = cls;
1500   struct Route *route = value;
1501   struct GNUNET_DV_ConnectMessage cm;
1502
1503   cm.header.size = htons (sizeof (cm));
1504   cm.header.type = htons (GNUNET_MESSAGE_TYPE_DV_CONNECT);
1505   cm.distance = htonl (route->target.distance);
1506   cm.peer = route->target.peer;
1507
1508   GNUNET_SERVER_notification_context_unicast (nc,
1509                                               client,
1510                                               &cm.header,
1511                                               GNUNET_NO);
1512   return GNUNET_OK;
1513 }
1514
1515
1516 /**
1517  * Handle START-message.  This is the first message sent to us
1518  * by the client (can only be one!).
1519  *
1520  * @param cls closure (always NULL)
1521  * @param client identification of the client
1522  * @param message the actual message
1523  */
1524 static void
1525 handle_start (void *cls, struct GNUNET_SERVER_Client *client,
1526               const struct GNUNET_MessageHeader *message)
1527 {
1528   GNUNET_SERVER_notification_context_add (nc, client);
1529   GNUNET_SERVER_receive_done (client, GNUNET_OK);
1530   GNUNET_CONTAINER_multihashmap_iterate (all_routes,
1531                                          &add_route,
1532                                          client);
1533 }
1534
1535
1536 /**
1537  * Called on core init.
1538  *
1539  * @param cls unused
1540  * @param server legacy
1541  * @param identity this peer's identity
1542  */
1543 static void
1544 core_init (void *cls, struct GNUNET_CORE_Handle *server,
1545            const struct GNUNET_PeerIdentity *identity)
1546 {
1547   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1548               "I am peer: %s\n",
1549               GNUNET_i2s (identity));
1550   my_identity = *identity;
1551 }
1552
1553
1554 /**
1555  * Process dv requests.
1556  *
1557  * @param cls closure
1558  * @param server the initialized server
1559  * @param c configuration to use
1560  */
1561 static void
1562 run (void *cls, struct GNUNET_SERVER_Handle *server,
1563      const struct GNUNET_CONFIGURATION_Handle *c)
1564 {
1565   static struct GNUNET_CORE_MessageHandler core_handlers[] = {
1566     {&handle_dv_route_message, GNUNET_MESSAGE_TYPE_DV_ROUTE, 0},
1567     {NULL, 0, 0}
1568   };
1569   static struct GNUNET_SERVER_MessageHandler plugin_handlers[] = {
1570     {&handle_start, NULL,
1571      GNUNET_MESSAGE_TYPE_DV_START,
1572      sizeof (struct GNUNET_MessageHeader) },
1573     { &handle_dv_send_message, NULL,
1574       GNUNET_MESSAGE_TYPE_DV_SEND,
1575       0},
1576     {NULL, NULL, 0, 0}
1577   };
1578
1579   cfg = c;
1580   direct_neighbors = GNUNET_CONTAINER_multihashmap_create (128, GNUNET_NO);
1581   all_routes = GNUNET_CONTAINER_multihashmap_create (65536, GNUNET_NO);
1582   core_api = GNUNET_CORE_connect (cfg, NULL,
1583                                   &core_init,
1584                                   &handle_core_connect,
1585                                   &handle_core_disconnect,
1586                                   NULL, GNUNET_NO,
1587                                   NULL, GNUNET_NO,
1588                                   core_handlers);
1589
1590   if (NULL == core_api)
1591     return;
1592   nc = GNUNET_SERVER_notification_context_create (server,
1593                                                   MAX_QUEUE_SIZE_PLUGIN);
1594   stats = GNUNET_STATISTICS_create ("dv", cfg);
1595   GNUNET_SERVER_add_handlers (server, plugin_handlers);
1596   GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL,
1597                                 &shutdown_task, NULL);
1598 }
1599
1600
1601 /**
1602  * The main function for the dv service.
1603  *
1604  * @param argc number of arguments from the command line
1605  * @param argv command line arguments
1606  * @return 0 ok, 1 on error
1607  */
1608 int
1609 main (int argc, char *const *argv)
1610 {
1611   return (GNUNET_OK ==
1612           GNUNET_SERVICE_run (argc, argv, "dv", GNUNET_SERVICE_OPTION_NONE,
1613                               &run, NULL)) ? 0 : 1;
1614 }
1615
1616 /* end of gnunet-service-dv.c */