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    * Queue for sending messages to this peer.
  59    */
  60   struct GNUNET_MQ_Handle *mq;
  61
  62   /**
  63    * What is the identity of the peer?
  64    */
  65   struct GNUNET_PeerIdentity id;
  66
  67   /**
  68    * Tasked used to trigger the set union operation.
  69    */
  70   struct GNUNET_SCHEDULER_Task *transmit_task;
  71
  72   /**
  73    * Handle to active set union operation (over revocation sets).
  74    */
  75   struct GNUNET_SET_OperationHandle *so;
  76 };
  77
  78
  79 /**
  80  * Set from all revocations known to us.
  81  */
  82 static struct GNUNET_SET_Handle *revocation_set;
  83
  84 /**
  85  * Hash map with all revoked keys, maps the hash of the public key
  86  * to the respective `struct RevokeMessage`.
  87  */
  88 static struct GNUNET_CONTAINER_MultiHashMap *revocation_map;
  89
  90 /**
  91  * Handle to our current configuration.
  92  */
  93 static const struct GNUNET_CONFIGURATION_Handle *cfg;
  94
  95 /**
  96  * Handle to the statistics service.
  97  */
  98 static struct GNUNET_STATISTICS_Handle *stats;
  99
 100 /**
 101  * Handle to the core service (for flooding)
 102  */
 103 static struct GNUNET_CORE_Handle *core_api;
 104
 105 /**
 106  * Map of all connected peers.
 107  */
 108 static struct GNUNET_CONTAINER_MultiPeerMap *peers;
 109
 110 /**
 111  * The peer identity of this peer.
 112  */
 113 static struct GNUNET_PeerIdentity my_identity;
 114
 115 /**
 116  * File handle for the revocation database.
 117  */
 118 static struct GNUNET_DISK_FileHandle *revocation_db;
 119
 120 /**
 121  * Handle for us listening to incoming revocation set union requests.
 122  */
 123 static struct GNUNET_SET_ListenHandle *revocation_union_listen_handle;
 124
 125 /**
 126  * Amount of work required (W-bit collisions) for REVOCATION proofs, in collision-bits.
 127  */
 128 static unsigned long long revocation_work_required;
 129
 130 /**
 131  * Our application ID for set union operations.  Must be the
 132  * same for all (compatible) peers.
 133  */
 134 static struct GNUNET_HashCode revocation_set_union_app_id;
 135
 136
 137 /**
 138  * Create a new PeerEntry and add it to the peers multipeermap.
 139  *
 140  * @param peer the peer identity
 141  * @return a pointer to the new PeerEntry
 142  */
 143 static struct PeerEntry *
 144 new_peer_entry(const struct GNUNET_PeerIdentity *peer)
 145 {
 146   struct PeerEntry *peer_entry;
 147
 148   peer_entry = GNUNET_new(struct PeerEntry);
 149   peer_entry->id = *peer;
 150   GNUNET_assert(GNUNET_OK ==
 151                 GNUNET_CONTAINER_multipeermap_put(peers,
 152                                                   &peer_entry->id,
 153                                                   peer_entry,
 154                                                   GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
 155   return peer_entry;
 156 }
 157
 158
 159 /**
 160  * An revoke message has been received, check that it is well-formed.
 161  *
 162  * @param rm the message to verify
 163  * @return #GNUNET_YES if the message is verified
 164  *         #GNUNET_NO if the key/signature don't verify
 165  */
 166 static int
 167 verify_revoke_message(const struct RevokeMessage *rm)
 168 {
 169   if (GNUNET_YES !=
 170       GNUNET_REVOCATION_check_pow(&rm->public_key,
 171                                   rm->proof_of_work,
 172                                   (unsigned int)revocation_work_required))
 173     {
 174       GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
 175                  "Proof of work invalid!\n");
 176       GNUNET_break_op(0);
 177       return GNUNET_NO;
 178     }
 179   if (GNUNET_OK !=
 180       GNUNET_CRYPTO_ecdsa_verify(GNUNET_SIGNATURE_PURPOSE_REVOCATION,
 181                                  &rm->purpose,
 182                                  &rm->signature,
 183                                  &rm->public_key))
 184     {
 185       GNUNET_break_op(0);
 186       return GNUNET_NO;
 187     }
 188   return GNUNET_YES;
 189 }
 190
 191
 192 /**
 193  * Handle client connecting to the service.
 194  *
 195  * @param cls NULL
 196  * @param client the new client
 197  * @param mq the message queue of @a client
 198  * @return @a client
 199  */
 200 static void *
 201 client_connect_cb(void *cls,
 202                   struct GNUNET_SERVICE_Client *client,
 203                   struct GNUNET_MQ_Handle *mq)
 204 {
 205   return client;
 206 }
 207
 208
 209 /**
 210  * Handle client connecting to the service.
 211  *
 212  * @param cls NULL
 213  * @param client the new client
 214  * @param app_cls must alias @a client
 215  */
 216 static void
 217 client_disconnect_cb(void *cls,
 218                      struct GNUNET_SERVICE_Client *client,
 219                      void *app_cls)
 220 {
 221   GNUNET_assert(client == app_cls);
 222 }
 223
 224
 225 /**
 226  * Handle QUERY message from client.
 227  *
 228  * @param cls client who sent the message
 229  * @param qm the message received
 230  */
 231 static void
 232 handle_query_message(void *cls,
 233                      const struct QueryMessage *qm)
 234 {
 235   struct GNUNET_SERVICE_Client *client = cls;
 236   struct GNUNET_MQ_Envelope *env;
 237   struct QueryResponseMessage *qrm;
 238   struct GNUNET_HashCode hc;
 239   int res;
 240
 241   GNUNET_CRYPTO_hash(&qm->key,
 242                      sizeof(struct GNUNET_CRYPTO_EcdsaPublicKey),
 243                      &hc);
 244   res = GNUNET_CONTAINER_multihashmap_contains(revocation_map,
 245                                                &hc);
 246   GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
 247              (GNUNET_NO == res)
 248              ? "Received revocation check for valid key `%s' from client\n"
 249              : "Received revocation check for revoked key `%s' from client\n",
 250              GNUNET_h2s(&hc));
 251   env = GNUNET_MQ_msg(qrm,
 252                       GNUNET_MESSAGE_TYPE_REVOCATION_QUERY_RESPONSE);
 253   qrm->is_valid = htonl((GNUNET_YES == res) ? GNUNET_NO : GNUNET_YES);
 254   GNUNET_MQ_send(GNUNET_SERVICE_client_get_mq(client),
 255                  env);
 256   GNUNET_SERVICE_client_continue(client);
 257 }
 258
 259
 260 /**
 261  * Flood the given revocation message to all neighbours.
 262  *
 263  * @param cls the `struct RevokeMessage` to flood
 264  * @param target a neighbour
 265  * @param value our `struct PeerEntry` for the neighbour
 266  * @return #GNUNET_OK (continue to iterate)
 267  */
 268 static int
 269 do_flood(void *cls,
 270          const struct GNUNET_PeerIdentity *target,
 271          void *value)
 272 {
 273   const struct RevokeMessage *rm = cls;
 274   struct PeerEntry *pe = value;
 275   struct GNUNET_MQ_Envelope *e;
 276   struct RevokeMessage *cp;
 277
 278   if (NULL == pe->mq)
 279     return GNUNET_OK; /* peer connected to us via SET,
 280                          but we have no direct CORE
 281                          connection for flooding */
 282   e = GNUNET_MQ_msg(cp,
 283                     GNUNET_MESSAGE_TYPE_REVOCATION_REVOKE);
 284   *cp = *rm;
 285   GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
 286              "Flooding revocation to `%s'\n",
 287              GNUNET_i2s(target));
 288   GNUNET_MQ_send(pe->mq,
 289                  e);
 290   return GNUNET_OK;
 291 }
 292
 293
 294 /**
 295  * Publicize revocation message.   Stores the message locally in the
 296  * database and passes it to all connected neighbours (and adds it to
 297  * the set for future connections).
 298  *
 299  * @param rm message to publicize
 300  * @return #GNUNET_OK on success, #GNUNET_NO if we encountered an error,
 301  *         #GNUNET_SYSERR if the message was malformed
 302  */
 303 static int
 304 publicize_rm(const struct RevokeMessage *rm)
 305 {
 306   struct RevokeMessage *cp;
 307   struct GNUNET_HashCode hc;
 308   struct GNUNET_SET_Element e;
 309
 310   GNUNET_CRYPTO_hash(&rm->public_key,
 311                      sizeof(struct GNUNET_CRYPTO_EcdsaPublicKey),
 312                      &hc);
 313   if (GNUNET_YES ==
 314       GNUNET_CONTAINER_multihashmap_contains(revocation_map,
 315                                              &hc))
 316     {
 317       GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
 318                  "Duplicate revocation received from peer. Ignored.\n");
 319       return GNUNET_OK;
 320     }
 321   if (GNUNET_OK !=
 322       verify_revoke_message(rm))
 323     {
 324       GNUNET_break_op(0);
 325       return GNUNET_SYSERR;
 326     }
 327   /* write to disk */
 328   if (sizeof(struct RevokeMessage) !=
 329       GNUNET_DISK_file_write(revocation_db,
 330                              rm,
 331                              sizeof(struct RevokeMessage)))
 332     {
 333       GNUNET_log_strerror(GNUNET_ERROR_TYPE_ERROR,
 334                           "write");
 335       return GNUNET_NO;
 336     }
 337   if (GNUNET_OK !=
 338       GNUNET_DISK_file_sync(revocation_db))
 339     {
 340       GNUNET_log_strerror(GNUNET_ERROR_TYPE_ERROR,
 341                           "sync");
 342       return GNUNET_NO;
 343     }
 344   /* keep copy in memory */
 345   cp = (struct RevokeMessage *)GNUNET_copy_message(&rm->header);
 346   GNUNET_break(GNUNET_OK ==
 347                GNUNET_CONTAINER_multihashmap_put(revocation_map,
 348                                                  &hc,
 349                                                  cp,
 350                                                  GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
 351   /* add to set for future connections */
 352   e.size = htons(rm->header.size);
 353   e.element_type = GNUNET_BLOCK_TYPE_REVOCATION;
 354   e.data = rm;
 355   if (GNUNET_OK !=
 356       GNUNET_SET_add_element(revocation_set,
 357                              &e,
 358                              NULL,
 359                              NULL))
 360     {
 361       GNUNET_break(0);
 362       return GNUNET_OK;
 363     }
 364   else
 365     {
 366       GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
 367                  "Added revocation info to SET\n");
 368     }
 369   /* flood to neighbours */
 370   GNUNET_CONTAINER_multipeermap_iterate(peers,
 371                                         &do_flood,
 372                                         cp);
 373   return GNUNET_OK;
 374 }
 375
 376
 377 /**
 378  * Handle REVOKE message from client.
 379  *
 380  * @param cls client who sent the message
 381  * @param rm the message received
 382  */
 383 static void
 384 handle_revoke_message(void *cls,
 385                       const struct RevokeMessage *rm)
 386 {
 387   struct GNUNET_SERVICE_Client *client = cls;
 388   struct GNUNET_MQ_Envelope *env;
 389   struct RevocationResponseMessage *rrm;
 390   int ret;
 391
 392   GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
 393              "Received REVOKE message from client\n");
 394   if (GNUNET_SYSERR == (ret = publicize_rm(rm)))
 395     {
 396       GNUNET_break_op(0);
 397       GNUNET_SERVICE_client_drop(client);
 398       return;
 399     }
 400   env = GNUNET_MQ_msg(rrm,
 401                       GNUNET_MESSAGE_TYPE_REVOCATION_REVOKE_RESPONSE);
 402   rrm->is_valid = htonl((GNUNET_OK == ret) ? GNUNET_NO : GNUNET_YES);
 403   GNUNET_MQ_send(GNUNET_SERVICE_client_get_mq(client),
 404                  env);
 405   GNUNET_SERVICE_client_continue(client);
 406 }
 407
 408
 409 /**
 410  * Core handler for flooded revocation messages.
 411  *
 412  * @param cls closure unused
 413  * @param rm revocation message
 414  */
 415 static void
 416 handle_p2p_revoke(void *cls,
 417                   const struct RevokeMessage *rm)
 418 {
 419   GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
 420              "Received REVOKE message\n");
 421   GNUNET_break_op(GNUNET_SYSERR !=
 422                   publicize_rm(rm));
 423 }
 424
 425
 426 /**
 427  * Callback for set operation results. Called for each element in the
 428  * result set.  Each element contains a revocation, which we should
 429  * validate and then add to our revocation list (and set).
 430  *
 431  * @param cls closure
 432  * @param element a result element, only valid if status is #GNUNET_SET_STATUS_OK
 433  * @param current_size current set size
 434  * @param status see `enum GNUNET_SET_Status`
 435  */
 436 static void
 437 add_revocation(void *cls,
 438                const struct GNUNET_SET_Element *element,
 439                uint64_t current_size,
 440                enum GNUNET_SET_Status status)
 441 {
 442   struct PeerEntry *peer_entry = cls;
 443   const struct RevokeMessage *rm;
 444
 445   switch (status)
 446     {
 447     case GNUNET_SET_STATUS_OK:
 448       if (element->size != sizeof(struct RevokeMessage))
 449         {
 450           GNUNET_break_op(0);
 451           return;
 452         }
 453       if (GNUNET_BLOCK_TYPE_REVOCATION != element->element_type)
 454         {
 455           GNUNET_STATISTICS_update(stats,
 456                                    gettext_noop("# unsupported revocations received via set union"),
 457                                    1,
 458                                    GNUNET_NO);
 459           return;
 460         }
 461       rm = element->data;
 462       (void)handle_p2p_revoke(NULL,
 463                               rm);
 464       GNUNET_STATISTICS_update(stats,
 465                                gettext_noop("# revocation messages received via set union"),
 466                                1, GNUNET_NO);
 467       break;
 468
 469     case GNUNET_SET_STATUS_FAILURE:
 470       GNUNET_log(GNUNET_ERROR_TYPE_WARNING,
 471                  _("Error computing revocation set union with %s\n"),
 472                  GNUNET_i2s(&peer_entry->id));
 473       peer_entry->so = NULL;
 474       GNUNET_STATISTICS_update(stats,
 475                                gettext_noop("# revocation set unions failed"),
 476                                1,
 477                                GNUNET_NO);
 478       break;
 479
 480     case GNUNET_SET_STATUS_HALF_DONE:
 481       break;
 482
 483     case GNUNET_SET_STATUS_DONE:
 484       peer_entry->so = NULL;
 485       GNUNET_STATISTICS_update(stats,
 486                                gettext_noop("# 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   revocation_set = GNUNET_SET_create(cfg,
 848                                      GNUNET_SET_OPERATION_UNION);
 849   revocation_union_listen_handle
 850     = GNUNET_SET_listen(cfg,
 851                         GNUNET_SET_OPERATION_UNION,
 852                         &revocation_set_union_app_id,
 853                         &handle_revocation_union_request,
 854                         NULL);
 855   revocation_db = GNUNET_DISK_file_open(fn,
 856                                         GNUNET_DISK_OPEN_READWRITE |
 857                                         GNUNET_DISK_OPEN_CREATE,
 858                                         GNUNET_DISK_PERM_USER_READ | GNUNET_DISK_PERM_USER_WRITE |
 859                                         GNUNET_DISK_PERM_GROUP_READ |
 860                                         GNUNET_DISK_PERM_OTHER_READ);
 861   if (NULL == revocation_db)
 862     {
 863       GNUNET_log_config_invalid(GNUNET_ERROR_TYPE_ERROR,
 864                                 "REVOCATION",
 865                                 "DATABASE",
 866                                 _("Could not open revocation database file!"));
 867       GNUNET_SCHEDULER_shutdown();
 868       GNUNET_free(fn);
 869       return;
 870     }
 871   if (GNUNET_OK !=
 872       GNUNET_DISK_file_size(fn, &left, GNUNET_YES, GNUNET_YES))
 873     left = 0;
 874   while (left > sizeof(struct RevokeMessage))
 875     {
 876       rm = GNUNET_new(struct RevokeMessage);
 877       if (sizeof(struct RevokeMessage) !=
 878           GNUNET_DISK_file_read(revocation_db,
 879                                 rm,
 880                                 sizeof(struct RevokeMessage)))
 881         {
 882           GNUNET_log_strerror_file(GNUNET_ERROR_TYPE_ERROR,
 883                                    "read",
 884                                    fn);
 885           GNUNET_free(rm);
 886           GNUNET_SCHEDULER_shutdown();
 887           GNUNET_free(fn);
 888           return;
 889         }
 890       GNUNET_break(0 == ntohl(rm->reserved));
 891       GNUNET_CRYPTO_hash(&rm->public_key,
 892                          sizeof(struct GNUNET_CRYPTO_EcdsaPublicKey),
 893                          &hc);
 894       GNUNET_break(GNUNET_OK ==
 895                    GNUNET_CONTAINER_multihashmap_put(revocation_map,
 896                                                      &hc,
 897                                                      rm,
 898                                                      GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
 899     }
 900   GNUNET_free(fn);
 901
 902   GNUNET_SCHEDULER_add_shutdown(&shutdown_task,
 903                                 NULL);
 904   peers = GNUNET_CONTAINER_multipeermap_create(128,
 905                                                GNUNET_YES);
 906   /* Connect to core service and register core handlers */
 907   core_api = GNUNET_CORE_connect(cfg,    /* Main configuration */
 908                                  NULL,        /* Closure passed to functions */
 909                                  &core_init,     /* Call core_init once connected */
 910                                  &handle_core_connect,   /* Handle connects */
 911                                  &handle_core_disconnect,        /* Handle disconnects */
 912                                  core_handlers);         /* Register these handlers */
 913   if (NULL == core_api)
 914     {
 915       GNUNET_SCHEDULER_shutdown();
 916       return;
 917     }
 918   stats = GNUNET_STATISTICS_create("revocation",
 919                                    cfg);
 920 }
 921
 922
 923 /**
 924  * Define "main" method using service macro.
 925  */
 926 GNUNET_SERVICE_MAIN
 927   ("revocation",
 928   GNUNET_SERVICE_OPTION_NONE,
 929   &run,
 930   &client_connect_cb,
 931   &client_disconnect_cb,
 932   NULL,
 933   GNUNET_MQ_hd_fixed_size(query_message,
 934                           GNUNET_MESSAGE_TYPE_REVOCATION_QUERY,
 935                           struct QueryMessage,
 936                           NULL),
 937   GNUNET_MQ_hd_fixed_size(revoke_message,
 938                           GNUNET_MESSAGE_TYPE_REVOCATION_REVOKE,
 939                           struct RevokeMessage,
 940                           NULL),
 941   GNUNET_MQ_handler_end());
 942
 943
 944 #if defined(LINUX) && defined(__GLIBC__)
 945 #include <malloc.h>
 946
 947 /**
 948  * MINIMIZE heap size (way below 128k) since this process doesn't need much.
 949  */
 950 void __attribute__ ((constructor))
 951 GNUNET_REVOCATION_memory_init()
 952 {
 953   mallopt(M_TRIM_THRESHOLD, 4 * 1024);
 954   mallopt(M_TOP_PAD, 1 * 1024);
 955   malloc_trim(0);
 956 }
 957
 958 #endif
 959
 960
 961 /* end of gnunet-service-revocation.c */