src/revocation/gnunet-service-revocation.c

   1 /*
   2    This file is part of GNUnet.
   3    Copyright (C) 2013, 2014, 2016 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 revocation/gnunet-service-revocation.c
  23  * @brief key revocation service
  24  * @author Christian Grothoff
  25  *
  26  * The purpose of this service is to allow users to permanently revoke
  27  * (compromised) keys.  This is done by flooding the network with the
  28  * revocation requests.  To reduce the attack potential offered by such
  29  * flooding, revocations must include a proof of work.  We use the
  30  * set service for efficiently computing the union of revocations of
  31  * peers that connect.
  32  *
  33  * TODO:
  34  * - optimization: avoid sending revocation back to peer that we got it from;
  35  * - optimization: have randomized delay in sending revocations to other peers
  36  *                 to make it rare to traverse each link twice (NSE-style)
  37  */
  38 #include "platform.h"
  39 #include <math.h>
  40 #include "gnunet_util_lib.h"
  41 #include "gnunet_block_lib.h"
  42 #include "gnunet_constants.h"
  43 #include "gnunet_protocols.h"
  44 #include "gnunet_signatures.h"
  45 #include "gnunet_statistics_service.h"
  46 #include "gnunet_core_service.h"
  47 #include "gnunet_revocation_service.h"
  48 #include "gnunet_set_service.h"
  49 #include "revocation.h"
  50 #include <gcrypt.h>
  51
  52
  53 /**
  54  * Per-peer information.
  55  */
  56 struct PeerEntry
  57 {
  58   /**
  59    * Queue for sending messages to this peer.
  60    */
  61   struct GNUNET_MQ_Handle *mq;
  62
  63   /**
  64    * What is the identity of the peer?
  65    */
  66   struct GNUNET_PeerIdentity id;
  67
  68   /**
  69    * Tasked used to trigger the set union operation.
  70    */
  71   struct GNUNET_SCHEDULER_Task *transmit_task;
  72
  73   /**
  74    * Handle to active set union operation (over revocation sets).
  75    */
  76   struct GNUNET_SET_OperationHandle *so;
  77 };
  78
  79
  80 /**
  81  * Set from all revocations known to us.
  82  */
  83 static struct GNUNET_SET_Handle *revocation_set;
  84
  85 /**
  86  * Hash map with all revoked keys, maps the hash of the public key
  87  * to the respective `struct RevokeMessage`.
  88  */
  89 static struct GNUNET_CONTAINER_MultiHashMap *revocation_map;
  90
  91 /**
  92  * Handle to our current configuration.
  93  */
  94 static const struct GNUNET_CONFIGURATION_Handle *cfg;
  95
  96 /**
  97  * Handle to the statistics service.
  98  */
  99 static struct GNUNET_STATISTICS_Handle *stats;
 100
 101 /**
 102  * Handle to the core service (for flooding)
 103  */
 104 static struct GNUNET_CORE_Handle *core_api;
 105
 106 /**
 107  * Map of all connected peers.
 108  */
 109 static struct GNUNET_CONTAINER_MultiPeerMap *peers;
 110
 111 /**
 112  * The peer identity of this peer.
 113  */
 114 static struct GNUNET_PeerIdentity my_identity;
 115
 116 /**
 117  * File handle for the revocation database.
 118  */
 119 static struct GNUNET_DISK_FileHandle *revocation_db;
 120
 121 /**
 122  * Handle for us listening to incoming revocation set union requests.
 123  */
 124 static struct GNUNET_SET_ListenHandle *revocation_union_listen_handle;
 125
 126 /**
 127  * Amount of work required (W-bit collisions) for REVOCATION proofs, in collision-bits.
 128  */
 129 static unsigned long long revocation_work_required;
 130
 131 /**
 132  * Length of an expiration expoch
 133  */
 134 static struct GNUNET_TIME_Relative epoch_duration;
 135
 136 /**
 137  * Our application ID for set union operations.  Must be the
 138  * same for all (compatible) peers.
 139  */
 140 static struct GNUNET_HashCode revocation_set_union_app_id;
 141
 142
 143 /**
 144  * Create a new PeerEntry and add it to the peers multipeermap.
 145  *
 146  * @param peer the peer identity
 147  * @return a pointer to the new PeerEntry
 148  */
 149 static struct PeerEntry *
 150 new_peer_entry (const struct GNUNET_PeerIdentity *peer)
 151 {
 152   struct PeerEntry *peer_entry;
 153
 154   peer_entry = GNUNET_new (struct PeerEntry);
 155   peer_entry->id = *peer;
 156   GNUNET_assert (GNUNET_OK ==
 157                  GNUNET_CONTAINER_multipeermap_put (peers,
 158                                                     &peer_entry->id,
 159                                                     peer_entry,
 160                                                     GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
 161   return peer_entry;
 162 }
 163
 164
 165 /**
 166  * An revoke message has been received, check that it is well-formed.
 167  *
 168  * @param rm the message to verify
 169  * @return #GNUNET_YES if the message is verified
 170  *         #GNUNET_NO if the key/signature don't verify
 171  */
 172 static int
 173 verify_revoke_message (const struct RevokeMessage *rm)
 174 {
 175   if (GNUNET_YES != GNUNET_REVOCATION_check_pow (&rm->proof_of_work,
 176                                                  (unsigned
 177                                                   int) revocation_work_required,
 178                                                  epoch_duration))
 179   {
 180     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 181                 "Proof of work invalid!\n");
 182     GNUNET_break_op (0);
 183     return GNUNET_NO;
 184   }
 185   return GNUNET_YES;
 186 }
 187
 188
 189 /**
 190  * Handle client connecting to the service.
 191  *
 192  * @param cls NULL
 193  * @param client the new client
 194  * @param mq the message queue of @a client
 195  * @return @a client
 196  */
 197 static void *
 198 client_connect_cb (void *cls,
 199                    struct GNUNET_SERVICE_Client *client,
 200                    struct GNUNET_MQ_Handle *mq)
 201 {
 202   return client;
 203 }
 204
 205
 206 /**
 207  * Handle client connecting to the service.
 208  *
 209  * @param cls NULL
 210  * @param client the new client
 211  * @param app_cls must alias @a client
 212  */
 213 static void
 214 client_disconnect_cb (void *cls,
 215                       struct GNUNET_SERVICE_Client *client,
 216                       void *app_cls)
 217 {
 218   GNUNET_assert (client == app_cls);
 219 }
 220
 221
 222 /**
 223  * Handle QUERY message from client.
 224  *
 225  * @param cls client who sent the message
 226  * @param qm the message received
 227  */
 228 static void
 229 handle_query_message (void *cls,
 230                       const struct QueryMessage *qm)
 231 {
 232   struct GNUNET_SERVICE_Client *client = cls;
 233   struct GNUNET_MQ_Envelope *env;
 234   struct QueryResponseMessage *qrm;
 235   struct GNUNET_HashCode hc;
 236   int res;
 237
 238   GNUNET_CRYPTO_hash (&qm->key,
 239                       sizeof(struct GNUNET_CRYPTO_EcdsaPublicKey),
 240                       &hc);
 241   res = GNUNET_CONTAINER_multihashmap_contains (revocation_map,
 242                                                 &hc);
 243   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 244               (GNUNET_NO == res)
 245               ? "Received revocation check for valid key `%s' from client\n"
 246               : "Received revocation check for revoked key `%s' from client\n",
 247               GNUNET_h2s (&hc));
 248   env = GNUNET_MQ_msg (qrm,
 249                        GNUNET_MESSAGE_TYPE_REVOCATION_QUERY_RESPONSE);
 250   qrm->is_valid = htonl ((GNUNET_YES == res) ? GNUNET_NO : GNUNET_YES);
 251   GNUNET_MQ_send (GNUNET_SERVICE_client_get_mq (client),
 252                   env);
 253   GNUNET_SERVICE_client_continue (client);
 254 }
 255
 256
 257 /**
 258  * Flood the given revocation message to all neighbours.
 259  *
 260  * @param cls the `struct RevokeMessage` to flood
 261  * @param target a neighbour
 262  * @param value our `struct PeerEntry` for the neighbour
 263  * @return #GNUNET_OK (continue to iterate)
 264  */
 265 static int
 266 do_flood (void *cls,
 267           const struct GNUNET_PeerIdentity *target,
 268           void *value)
 269 {
 270   const struct RevokeMessage *rm = cls;
 271   struct PeerEntry *pe = value;
 272   struct GNUNET_MQ_Envelope *e;
 273   struct RevokeMessage *cp;
 274
 275   if (NULL == pe->mq)
 276     return GNUNET_OK; /* peer connected to us via SET,
 277                          but we have no direct CORE
 278                          connection for flooding */
 279   e = GNUNET_MQ_msg (cp,
 280                      GNUNET_MESSAGE_TYPE_REVOCATION_REVOKE);
 281   *cp = *rm;
 282   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 283               "Flooding revocation to `%s'\n",
 284               GNUNET_i2s (target));
 285   GNUNET_MQ_send (pe->mq,
 286                   e);
 287   return GNUNET_OK;
 288 }
 289
 290
 291 /**
 292  * Publicize revocation message.   Stores the message locally in the
 293  * database and passes it to all connected neighbours (and adds it to
 294  * the set for future connections).
 295  *
 296  * @param rm message to publicize
 297  * @return #GNUNET_OK on success, #GNUNET_NO if we encountered an error,
 298  *         #GNUNET_SYSERR if the message was malformed
 299  */
 300 static int
 301 publicize_rm (const struct RevokeMessage *rm)
 302 {
 303   struct RevokeMessage *cp;
 304   struct GNUNET_HashCode hc;
 305   struct GNUNET_SET_Element e;
 306
 307   GNUNET_CRYPTO_hash (&rm->proof_of_work.key,
 308                       sizeof(struct GNUNET_CRYPTO_EcdsaPublicKey),
 309                       &hc);
 310   if (GNUNET_YES ==
 311       GNUNET_CONTAINER_multihashmap_contains (revocation_map,
 312                                               &hc))
 313   {
 314     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 315                 "Duplicate revocation received from peer. Ignored.\n");
 316     return GNUNET_OK;
 317   }
 318   if (GNUNET_OK !=
 319       verify_revoke_message (rm))
 320   {
 321     GNUNET_break_op (0);
 322     return GNUNET_SYSERR;
 323   }
 324   /* write to disk */
 325   if (sizeof(struct RevokeMessage) !=
 326       GNUNET_DISK_file_write (revocation_db,
 327                               rm,
 328                               sizeof(struct RevokeMessage)))
 329   {
 330     GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR,
 331                          "write");
 332     return GNUNET_NO;
 333   }
 334   if (GNUNET_OK !=
 335       GNUNET_DISK_file_sync (revocation_db))
 336   {
 337     GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR,
 338                          "sync");
 339     return GNUNET_NO;
 340   }
 341   /* keep copy in memory */
 342   cp = (struct RevokeMessage *) GNUNET_copy_message (&rm->header);
 343   GNUNET_break (GNUNET_OK ==
 344                 GNUNET_CONTAINER_multihashmap_put (revocation_map,
 345                                                    &hc,
 346                                                    cp,
 347                                                    GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
 348   /* add to set for future connections */
 349   e.size = htons (rm->header.size);
 350   e.element_type = GNUNET_BLOCK_TYPE_REVOCATION;
 351   e.data = rm;
 352   if (GNUNET_OK !=
 353       GNUNET_SET_add_element (revocation_set,
 354                               &e,
 355                               NULL,
 356                               NULL))
 357   {
 358     GNUNET_break (0);
 359     return GNUNET_OK;
 360   }
 361   else
 362   {
 363     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 364                 "Added revocation info to SET\n");
 365   }
 366   /* flood to neighbours */
 367   GNUNET_CONTAINER_multipeermap_iterate (peers,
 368                                          &do_flood,
 369                                          cp);
 370   return GNUNET_OK;
 371 }
 372
 373
 374 /**
 375  * Handle REVOKE message from client.
 376  *
 377  * @param cls client who sent the message
 378  * @param rm the message received
 379  */
 380 static void
 381 handle_revoke_message (void *cls,
 382                        const struct RevokeMessage *rm)
 383 {
 384   struct GNUNET_SERVICE_Client *client = cls;
 385   struct GNUNET_MQ_Envelope *env;
 386   struct RevocationResponseMessage *rrm;
 387   int ret;
 388
 389   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 390               "Received REVOKE message from client\n");
 391   if (GNUNET_SYSERR == (ret = publicize_rm (rm)))
 392   {
 393     GNUNET_break_op (0);
 394     GNUNET_SERVICE_client_drop (client);
 395     return;
 396   }
 397   env = GNUNET_MQ_msg (rrm,
 398                        GNUNET_MESSAGE_TYPE_REVOCATION_REVOKE_RESPONSE);
 399   rrm->is_valid = htonl ((GNUNET_OK == ret) ? GNUNET_NO : GNUNET_YES);
 400   GNUNET_MQ_send (GNUNET_SERVICE_client_get_mq (client),
 401                   env);
 402   GNUNET_SERVICE_client_continue (client);
 403 }
 404
 405
 406 /**
 407  * Core handler for flooded revocation messages.
 408  *
 409  * @param cls closure unused
 410  * @param rm revocation message
 411  */
 412 static void
 413 handle_p2p_revoke (void *cls,
 414                    const struct RevokeMessage *rm)
 415 {
 416   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 417               "Received REVOKE message\n");
 418   GNUNET_break_op (GNUNET_SYSERR !=
 419                    publicize_rm (rm));
 420 }
 421
 422
 423 /**
 424  * Callback for set operation results. Called for each element in the
 425  * result set.  Each element contains a revocation, which we should
 426  * validate and then add to our revocation list (and set).
 427  *
 428  * @param cls closure
 429  * @param element a result element, only valid if status is #GNUNET_SET_STATUS_OK
 430  * @param current_size current set size
 431  * @param status see `enum GNUNET_SET_Status`
 432  */
 433 static void
 434 add_revocation (void *cls,
 435                 const struct GNUNET_SET_Element *element,
 436                 uint64_t current_size,
 437                 enum GNUNET_SET_Status status)
 438 {
 439   struct PeerEntry *peer_entry = cls;
 440   const struct RevokeMessage *rm;
 441
 442   switch (status)
 443   {
 444   case GNUNET_SET_STATUS_OK:
 445     if (element->size != sizeof(struct RevokeMessage))
 446     {
 447       GNUNET_break_op (0);
 448       return;
 449     }
 450     if (GNUNET_BLOCK_TYPE_REVOCATION != element->element_type)
 451     {
 452       GNUNET_STATISTICS_update (stats,
 453                                 gettext_noop (
 454                                   "# unsupported revocations received via set union"),
 455                                 1,
 456                                 GNUNET_NO);
 457       return;
 458     }
 459     rm = element->data;
 460     (void) handle_p2p_revoke (NULL,
 461                               rm);
 462     GNUNET_STATISTICS_update (stats,
 463                               gettext_noop (
 464                                 "# revocation messages received via set union"),
 465                               1, GNUNET_NO);
 466     break;
 467
 468   case GNUNET_SET_STATUS_FAILURE:
 469     GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
 470                 _ ("Error computing revocation set union with %s\n"),
 471                 GNUNET_i2s (&peer_entry->id));
 472     peer_entry->so = NULL;
 473     GNUNET_STATISTICS_update (stats,
 474                               gettext_noop ("# revocation set unions failed"),
 475                               1,
 476                               GNUNET_NO);
 477     break;
 478
 479   case GNUNET_SET_STATUS_HALF_DONE:
 480     break;
 481
 482   case GNUNET_SET_STATUS_DONE:
 483     peer_entry->so = NULL;
 484     GNUNET_STATISTICS_update (stats,
 485                               gettext_noop (
 486                                 "# revocation set unions completed"),
 487                               1,
 488                               GNUNET_NO);
 489     break;
 490
 491   default:
 492     GNUNET_break (0);
 493     break;
 494   }
 495 }
 496
 497
 498 /**
 499  * The timeout for performing the set union has expired,
 500  * run the set operation on the revocation certificates.
 501  *
 502  * @param cls NULL
 503  */
 504 static void
 505 transmit_task_cb (void *cls)
 506 {
 507   struct PeerEntry *peer_entry = cls;
 508
 509   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 510               "Starting set exchange with peer `%s'\n",
 511               GNUNET_i2s (&peer_entry->id));
 512   peer_entry->transmit_task = NULL;
 513   GNUNET_assert (NULL == peer_entry->so);
 514   peer_entry->so = GNUNET_SET_prepare (&peer_entry->id,
 515                                        &revocation_set_union_app_id,
 516                                        NULL,
 517                                        GNUNET_SET_RESULT_ADDED,
 518                                        (struct GNUNET_SET_Option[]) { { 0 } },
 519                                        &add_revocation,
 520                                        peer_entry);
 521   if (GNUNET_OK !=
 522       GNUNET_SET_commit (peer_entry->so,
 523                          revocation_set))
 524   {
 525     GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
 526                 _ ("SET service crashed, terminating revocation service\n"));
 527     GNUNET_SCHEDULER_shutdown ();
 528     return;
 529   }
 530 }
 531
 532
 533 /**
 534  * Method called whenever a peer connects. Sets up the PeerEntry and
 535  * schedules the initial revocation set exchange with this peer.
 536  *
 537  * @param cls closure
 538  * @param peer peer identity this notification is about
 539  */
 540 static void *
 541 handle_core_connect (void *cls,
 542                      const struct GNUNET_PeerIdentity *peer,
 543                      struct GNUNET_MQ_Handle *mq)
 544 {
 545   struct PeerEntry *peer_entry;
 546   struct GNUNET_HashCode my_hash;
 547   struct GNUNET_HashCode peer_hash;
 548
 549   if (0 == GNUNET_memcmp (peer,
 550                           &my_identity))
 551   {
 552     return NULL;
 553   }
 554
 555   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 556               "Peer `%s' connected to us\n",
 557               GNUNET_i2s (peer));
 558   GNUNET_STATISTICS_update (stats,
 559                             "# peers connected",
 560                             1,
 561                             GNUNET_NO);
 562   peer_entry = GNUNET_CONTAINER_multipeermap_get (peers,
 563                                                   peer);
 564   if (NULL != peer_entry)
 565   {
 566     /* This can happen if "core"'s notification is a tad late
 567        and CADET+SET were faster and already produced a
 568      #handle_revocation_union_request() for us to deal
 569        with.  This should be rare, but isn't impossible. */
 570     peer_entry->mq = mq;
 571     return peer_entry;
 572   }
 573   peer_entry = new_peer_entry (peer);
 574   peer_entry->mq = mq;
 575   GNUNET_CRYPTO_hash (&my_identity,
 576                       sizeof(my_identity),
 577                       &my_hash);
 578   GNUNET_CRYPTO_hash (peer,
 579                       sizeof(*peer),
 580                       &peer_hash);
 581   if (0 < GNUNET_CRYPTO_hash_cmp (&my_hash,
 582                                   &peer_hash))
 583   {
 584     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 585                 "Starting SET operation with peer `%s'\n",
 586                 GNUNET_i2s (peer));
 587     peer_entry->transmit_task =
 588       GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_SECONDS,
 589                                     &transmit_task_cb,
 590                                     peer_entry);
 591   }
 592   return peer_entry;
 593 }
 594
 595
 596 /**
 597  * Method called whenever a peer disconnects. Deletes the PeerEntry and cancels
 598  * any pending transmission requests to that peer.
 599  *
 600  * @param cls closure
 601  * @param peer peer identity this notification is about
 602  * @param internal_cls our `struct PeerEntry` for this peer
 603  */
 604 static void
 605 handle_core_disconnect (void *cls,
 606                         const struct GNUNET_PeerIdentity *peer,
 607                         void *internal_cls)
 608 {
 609   struct PeerEntry *peer_entry = internal_cls;
 610
 611   if (0 == GNUNET_memcmp (peer,
 612                           &my_identity))
 613     return;
 614   GNUNET_assert (NULL != peer_entry);
 615   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 616               "Peer `%s' disconnected from us\n",
 617               GNUNET_i2s (peer));
 618   GNUNET_assert (GNUNET_YES ==
 619                  GNUNET_CONTAINER_multipeermap_remove (peers,
 620                                                        peer,
 621                                                        peer_entry));
 622   if (NULL != peer_entry->transmit_task)
 623   {
 624     GNUNET_SCHEDULER_cancel (peer_entry->transmit_task);
 625     peer_entry->transmit_task = NULL;
 626   }
 627   if (NULL != peer_entry->so)
 628   {
 629     GNUNET_SET_operation_cancel (peer_entry->so);
 630     peer_entry->so = NULL;
 631   }
 632   GNUNET_free (peer_entry);
 633   GNUNET_STATISTICS_update (stats,
 634                             "# peers connected",
 635                             -1,
 636                             GNUNET_NO);
 637 }
 638
 639
 640 /**
 641  * Free all values in a hash map.
 642  *
 643  * @param cls NULL
 644  * @param key the key
 645  * @param value value to free
 646  * @return #GNUNET_OK (continue to iterate)
 647  */
 648 static int
 649 free_entry (void *cls,
 650             const struct GNUNET_HashCode *key,
 651             void *value)
 652 {
 653   GNUNET_free (value);
 654   return GNUNET_OK;
 655 }
 656
 657
 658 /**
 659  * Task run during shutdown.
 660  *
 661  * @param cls unused
 662  */
 663 static void
 664 shutdown_task (void *cls)
 665 {
 666   if (NULL != revocation_set)
 667   {
 668     GNUNET_SET_destroy (revocation_set);
 669     revocation_set = NULL;
 670   }
 671   if (NULL != revocation_union_listen_handle)
 672   {
 673     GNUNET_SET_listen_cancel (revocation_union_listen_handle);
 674     revocation_union_listen_handle = NULL;
 675   }
 676   if (NULL != core_api)
 677   {
 678     GNUNET_CORE_disconnect (core_api);
 679     core_api = NULL;
 680   }
 681   if (NULL != stats)
 682   {
 683     GNUNET_STATISTICS_destroy (stats, GNUNET_NO);
 684     stats = NULL;
 685   }
 686   if (NULL != peers)
 687   {
 688     GNUNET_CONTAINER_multipeermap_destroy (peers);
 689     peers = NULL;
 690   }
 691   if (NULL != revocation_db)
 692   {
 693     GNUNET_DISK_file_close (revocation_db);
 694     revocation_db = NULL;
 695   }
 696   GNUNET_CONTAINER_multihashmap_iterate (revocation_map,
 697                                          &free_entry,
 698                                          NULL);
 699   GNUNET_CONTAINER_multihashmap_destroy (revocation_map);
 700 }
 701
 702
 703 /**
 704  * Called on core init/fail.
 705  *
 706  * @param cls service closure
 707  * @param identity the public identity of this peer
 708  */
 709 static void
 710 core_init (void *cls,
 711            const struct GNUNET_PeerIdentity *identity)
 712 {
 713   if (NULL == identity)
 714   {
 715     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
 716                 "Connection to core FAILED!\n");
 717     GNUNET_SCHEDULER_shutdown ();
 718     return;
 719   }
 720   my_identity = *identity;
 721 }
 722
 723
 724 /**
 725  * Called when another peer wants to do a set operation with the
 726  * local peer. If a listen error occurs, the 'request' is NULL.
 727  *
 728  * @param cls closure
 729  * @param other_peer the other peer
 730  * @param context_msg message with application specific information from
 731  *        the other peer
 732  * @param request request from the other peer (never NULL), use GNUNET_SET_accept()
 733  *        to accept it, otherwise the request will be refused
 734  *        Note that we can't just return value from the listen callback,
 735  *        as it is also necessary to specify the set we want to do the
 736  *        operation with, whith sometimes can be derived from the context
 737  *        message. It's necessary to specify the timeout.
 738  */
 739 static void
 740 handle_revocation_union_request (void *cls,
 741                                  const struct GNUNET_PeerIdentity *other_peer,
 742                                  const struct GNUNET_MessageHeader *context_msg,
 743                                  struct GNUNET_SET_Request *request)
 744 {
 745   struct PeerEntry *peer_entry;
 746
 747   if (NULL == request)
 748   {
 749     GNUNET_break (0);
 750     return;
 751   }
 752   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 753               "Received set exchange request from peer `%s'\n",
 754               GNUNET_i2s (other_peer));
 755   peer_entry = GNUNET_CONTAINER_multipeermap_get (peers,
 756                                                   other_peer);
 757   if (NULL == peer_entry)
 758   {
 759     peer_entry = new_peer_entry (other_peer);
 760   }
 761   if (NULL != peer_entry->so)
 762   {
 763     GNUNET_break_op (0);
 764     return;
 765   }
 766   peer_entry->so = GNUNET_SET_accept (request,
 767                                       GNUNET_SET_RESULT_ADDED,
 768                                       (struct GNUNET_SET_Option[]) { { 0 } },
 769                                       &add_revocation,
 770                                       peer_entry);
 771   if (GNUNET_OK !=
 772       GNUNET_SET_commit (peer_entry->so,
 773                          revocation_set))
 774   {
 775     GNUNET_break (0);
 776     GNUNET_SCHEDULER_shutdown ();
 777     return;
 778   }
 779 }
 780
 781
 782 /**
 783  * Handle network size estimate clients.
 784  *
 785  * @param cls closure
 786  * @param server the initialized server
 787  * @param c configuration to use
 788  */
 789 static void
 790 run (void *cls,
 791      const struct GNUNET_CONFIGURATION_Handle *c,
 792      struct GNUNET_SERVICE_Handle *service)
 793 {
 794   struct GNUNET_MQ_MessageHandler core_handlers[] = {
 795     GNUNET_MQ_hd_fixed_size (p2p_revoke,
 796                              GNUNET_MESSAGE_TYPE_REVOCATION_REVOKE,
 797                              struct RevokeMessage,
 798                              NULL),
 799     GNUNET_MQ_handler_end ()
 800   };
 801   char *fn;
 802   uint64_t left;
 803   struct RevokeMessage *rm;
 804   struct GNUNET_HashCode hc;
 805
 806   GNUNET_CRYPTO_hash ("revocation-set-union-application-id",
 807                       strlen ("revocation-set-union-application-id"),
 808                       &revocation_set_union_app_id);
 809   if (GNUNET_OK !=
 810       GNUNET_CONFIGURATION_get_value_filename (c,
 811                                                "REVOCATION",
 812                                                "DATABASE",
 813                                                &fn))
 814   {
 815     GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR,
 816                                "REVOCATION",
 817                                "DATABASE");
 818     GNUNET_SCHEDULER_shutdown ();
 819     return;
 820   }
 821   cfg = c;
 822   revocation_map = GNUNET_CONTAINER_multihashmap_create (16,
 823                                                          GNUNET_NO);
 824   if (GNUNET_OK !=
 825       GNUNET_CONFIGURATION_get_value_number (cfg,
 826                                              "REVOCATION",
 827                                              "WORKBITS",
 828                                              &revocation_work_required))
 829   {
 830     GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR,
 831                                "REVOCATION",
 832                                "WORKBITS");
 833     GNUNET_SCHEDULER_shutdown ();
 834     GNUNET_free (fn);
 835     return;
 836   }
 837   if (revocation_work_required >= sizeof(struct GNUNET_HashCode) * 8)
 838   {
 839     GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
 840                                "REVOCATION",
 841                                "WORKBITS",
 842                                _ ("Value is too large.\n"));
 843     GNUNET_SCHEDULER_shutdown ();
 844     GNUNET_free (fn);
 845     return;
 846   }
 847   if (GNUNET_OK !=
 848       GNUNET_CONFIGURATION_get_value_time (cfg,
 849                                            "REVOCATION",
 850                                            "EPOCH_DURATION",
 851                                            &epoch_duration))
 852   {
 853     GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR,
 854                                "REVOCATION",
 855                                "EPOCH_DURATION");
 856     GNUNET_SCHEDULER_shutdown ();
 857     GNUNET_free (fn);
 858     return;
 859   }
 860
 861   revocation_set = GNUNET_SET_create (cfg,
 862                                       GNUNET_SET_OPERATION_UNION);
 863   revocation_union_listen_handle
 864     = GNUNET_SET_listen (cfg,
 865                          GNUNET_SET_OPERATION_UNION,
 866                          &revocation_set_union_app_id,
 867                          &handle_revocation_union_request,
 868                          NULL);
 869   revocation_db = GNUNET_DISK_file_open (fn,
 870                                          GNUNET_DISK_OPEN_READWRITE
 871                                          | GNUNET_DISK_OPEN_CREATE,
 872                                          GNUNET_DISK_PERM_USER_READ
 873                                          | GNUNET_DISK_PERM_USER_WRITE
 874                                          | GNUNET_DISK_PERM_GROUP_READ
 875                                          | GNUNET_DISK_PERM_OTHER_READ);
 876   if (NULL == revocation_db)
 877   {
 878     GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
 879                                "REVOCATION",
 880                                "DATABASE",
 881                                _ ("Could not open revocation database file!"));
 882     GNUNET_SCHEDULER_shutdown ();
 883     GNUNET_free (fn);
 884     return;
 885   }
 886   if (GNUNET_OK !=
 887       GNUNET_DISK_file_size (fn, &left, GNUNET_YES, GNUNET_YES))
 888     left = 0;
 889   while (left > sizeof(struct RevokeMessage))
 890   {
 891     rm = GNUNET_new (struct RevokeMessage);
 892     if (sizeof(struct RevokeMessage) !=
 893         GNUNET_DISK_file_read (revocation_db,
 894                                rm,
 895                                sizeof(struct RevokeMessage)))
 896     {
 897       GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_ERROR,
 898                                 "read",
 899                                 fn);
 900       GNUNET_free (rm);
 901       GNUNET_SCHEDULER_shutdown ();
 902       GNUNET_free (fn);
 903       return;
 904     }
 905     GNUNET_break (0 == ntohl (rm->reserved));
 906     GNUNET_CRYPTO_hash (&rm->proof_of_work.key,
 907                         sizeof(struct GNUNET_CRYPTO_EcdsaPublicKey),
 908                         &hc);
 909     GNUNET_break (GNUNET_OK ==
 910                   GNUNET_CONTAINER_multihashmap_put (revocation_map,
 911                                                      &hc,
 912                                                      rm,
 913                                                      GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
 914   }
 915   GNUNET_free (fn);
 916
 917   GNUNET_SCHEDULER_add_shutdown (&shutdown_task,
 918                                  NULL);
 919   peers = GNUNET_CONTAINER_multipeermap_create (128,
 920                                                 GNUNET_YES);
 921   /* Connect to core service and register core handlers */
 922   core_api = GNUNET_CORE_connect (cfg,    /* Main configuration */
 923                                   NULL,       /* Closure passed to functions */
 924                                   &core_init,    /* Call core_init once connected */
 925                                   &handle_core_connect,  /* Handle connects */
 926                                   &handle_core_disconnect,       /* Handle disconnects */
 927                                   core_handlers);        /* Register these handlers */
 928   if (NULL == core_api)
 929   {
 930     GNUNET_SCHEDULER_shutdown ();
 931     return;
 932   }
 933   stats = GNUNET_STATISTICS_create ("revocation",
 934                                     cfg);
 935 }
 936
 937
 938 /**
 939  * Define "main" method using service macro.
 940  */
 941 GNUNET_SERVICE_MAIN
 942   ("revocation",
 943   GNUNET_SERVICE_OPTION_NONE,
 944   &run,
 945   &client_connect_cb,
 946   &client_disconnect_cb,
 947   NULL,
 948   GNUNET_MQ_hd_fixed_size (query_message,
 949                            GNUNET_MESSAGE_TYPE_REVOCATION_QUERY,
 950                            struct QueryMessage,
 951                            NULL),
 952   GNUNET_MQ_hd_fixed_size (revoke_message,
 953                            GNUNET_MESSAGE_TYPE_REVOCATION_REVOKE,
 954                            struct RevokeMessage,
 955                            NULL),
 956   GNUNET_MQ_handler_end ());
 957
 958
 959 #if defined(__linux__) && defined(__GLIBC__)
 960 #include <malloc.h>
 961
 962 /**
 963  * MINIMIZE heap size (way below 128k) since this process doesn't need much.
 964  */
 965 void __attribute__ ((constructor))
 966 GNUNET_REVOCATION_memory_init ()
 967 {
 968   mallopt (M_TRIM_THRESHOLD, 4 * 1024);
 969   mallopt (M_TOP_PAD, 1 * 1024);
 970   malloc_trim (0);
 971 }
 972
 973
 974 #endif
 975
 976
 977 /* end of gnunet-service-revocation.c */