2 This file is part of GNUnet
3 (C) 2012, 2013 Christian Grothoff (and other contributing authors)
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.
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.
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.
22 * @file consensus/gnunet-service-consensus.c
23 * @brief multi-peer set reconciliation
24 * @author Florian Dold
28 #include "gnunet_common.h"
29 #include "gnunet_protocols.h"
30 #include "gnunet_applications.h"
31 #include "gnunet_util_lib.h"
32 #include "gnunet_set_service.h"
33 #include "gnunet_consensus_service.h"
34 #include "consensus_protocol.h"
35 #include "consensus.h"
39 * Log macro that prefixes the local peer and the peer we are in contact with.
41 #define LOG_PP(kind, cpi, m,...) GNUNET_log (kind, "P%d for P%d: " m, \
42 cpi->session->local_peer_idx, (int) (cpi - cpi->session->info),##__VA_ARGS__)
46 * Number of exponential rounds, used in the exp and completion round.
48 #define NUM_EXP_ROUNDS 4
50 /* forward declarations */
52 /* mutual recursion with struct ConsensusSession */
53 struct ConsensusPeerInformation;
55 /* mutual recursion with round_over */
57 subround_over (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc);
61 * Describes the current round a consensus session is in.
66 * Not started the protocol yet.
68 CONSENSUS_ROUND_BEGIN=0,
70 * Distribution of elements with the exponential scheme.
72 CONSENSUS_ROUND_EXCHANGE,
74 * Exchange which elements each peer has, but don't
75 * transmit the element's data, only their SHA-512 hashes.
76 * This round uses the all-to-all scheme.
78 CONSENSUS_ROUND_INVENTORY,
80 * Collect and distribute missing values with the exponential scheme.
82 CONSENSUS_ROUND_COMPLETION,
84 * Consensus concluded. After timeout and finished communication with client,
85 * consensus session will be destroyed.
87 CONSENSUS_ROUND_FINISH
92 * Complete information about the current round and all
98 * The current main round.
100 enum ConsensusRound round;
102 * The current exp round, valid if
103 * the main round is an exp round.
107 * The current exp subround, valid if
108 * the main round is an exp round.
110 uint32_t exp_subround;
115 * A consensus session consists of one local client and the remote authorities.
117 struct ConsensusSession
120 * Consensus sessions are kept in a DLL.
122 struct ConsensusSession *next;
125 * Consensus sessions are kept in a DLL.
127 struct ConsensusSession *prev;
130 * Global consensus identification, computed
131 * from the session id and participating authorities.
133 struct GNUNET_HashCode global_id;
136 * Client that inhabits the session
138 struct GNUNET_SERVER_Client *client;
141 * Queued messages to the client.
143 struct GNUNET_MQ_Handle *client_mq;
146 * Timeout for all rounds together, single rounds will schedule a timeout task
147 * with a fraction of the conclude timeout.
148 * Only valid once the current round is not CONSENSUS_ROUND_BEGIN.
150 struct GNUNET_TIME_Relative conclude_timeout;
153 * Timeout task identifier for the current round.
155 GNUNET_SCHEDULER_TaskIdentifier round_timeout_tid;
158 * Number of other peers in the consensus.
160 unsigned int num_peers;
163 * Information about the other peers,
166 struct ConsensusPeerInformation *info;
169 * Index of the local peer in the peers array
171 unsigned int local_peer_idx;
176 enum ConsensusRound current_round;
179 * Permutation of peers for the current round,
184 * Inverse permutation of peers for the current round,
186 uint32_t *shuffle_inv;
189 * Current round of the exponential scheme.
194 * Current sub-round of the exponential scheme.
196 uint32_t exp_subround;
199 * The partner for the current exp-round
201 struct ConsensusPeerInformation *partner_outgoing;
204 * The partner for the current exp-round
206 struct ConsensusPeerInformation *partner_incoming;
209 * The consensus set of this session.
211 struct GNUNET_SET_Handle *element_set;
214 * Listener for requests from other peers.
215 * Uses the session's global id as app id.
217 struct GNUNET_SET_ListenHandle *set_listener;
222 * Information about a peer that is in a consensus session.
224 struct ConsensusPeerInformation
227 * Peer identitty of the peer in the consensus session
229 struct GNUNET_PeerIdentity peer_id;
232 * Back-reference to the consensus session,
233 * to that ConsensusPeerInformation can be used as a closure
235 struct ConsensusSession *session;
238 * We have finishes the exp-subround with the peer.
240 int exp_subround_finished;
243 * Set operation we are currently executing with this peer.
245 struct GNUNET_SET_OperationHandle *set_op;
248 * Set operation we are planning on executing with this peer.
250 struct GNUNET_SET_OperationHandle *delayed_set_op;
253 * Info about the round of the delayed set operation.
255 struct RoundInfo delayed_round_info;
260 * Linked list of sessions this peer participates in.
262 static struct ConsensusSession *sessions_head;
265 * Linked list of sessions this peer participates in.
267 static struct ConsensusSession *sessions_tail;
270 * Configuration of the consensus service.
272 static const struct GNUNET_CONFIGURATION_Handle *cfg;
275 * Handle to the server for this service.
277 static struct GNUNET_SERVER_Handle *srv;
280 * Peer that runs this service.
282 static struct GNUNET_PeerIdentity my_peer;
286 have_exp_subround_finished (const struct ConsensusSession *session)
290 if ( (NULL != session->partner_outgoing) &&
291 (GNUNET_NO == session->partner_outgoing->exp_subround_finished) )
293 if ( (NULL != session->partner_incoming) &&
294 (GNUNET_NO == session->partner_incoming->exp_subround_finished) )
296 if (0 == not_finished)
303 * Destroy a session, free all resources associated with it.
305 * @param session the session to destroy
308 destroy_session (struct ConsensusSession *session)
312 GNUNET_CONTAINER_DLL_remove (sessions_head, sessions_tail, session);
313 if (NULL != session->element_set)
315 GNUNET_SET_destroy (session->element_set);
316 session->element_set = NULL;
318 if (NULL != session->set_listener)
320 GNUNET_SET_listen_cancel (session->set_listener);
321 session->set_listener = NULL;
323 if (NULL != session->client_mq)
325 GNUNET_MQ_destroy (session->client_mq);
326 session->client_mq = NULL;
328 if (NULL != session->client)
330 GNUNET_SERVER_client_disconnect (session->client);
331 session->client = NULL;
333 if (NULL != session->shuffle)
335 GNUNET_free (session->shuffle);
336 session->shuffle = NULL;
338 if (NULL != session->shuffle_inv)
340 GNUNET_free (session->shuffle_inv);
341 session->shuffle_inv = NULL;
343 if (NULL != session->info)
345 for (i = 0; i < session->num_peers; i++)
347 struct ConsensusPeerInformation *cpi;
348 cpi = &session->info[i];
349 if (NULL != cpi->set_op)
351 GNUNET_SET_operation_cancel (cpi->set_op);
355 GNUNET_free (session->info);
356 session->info = NULL;
358 GNUNET_free (session);
363 * Iterator for set elements.
366 * @param element the current element, NULL if all elements have been
368 * @return GNUNET_YES to continue iterating, GNUNET_NO to stop.
371 send_to_client_iter (void *cls,
372 const struct GNUNET_SET_Element *element)
374 struct ConsensusSession *session = cls;
375 struct GNUNET_MQ_Envelope *ev;
379 struct GNUNET_CONSENSUS_ElementMessage *m;
381 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%d: got element for client\n",
382 session->local_peer_idx);
384 ev = GNUNET_MQ_msg_extra (m, element->size, GNUNET_MESSAGE_TYPE_CONSENSUS_CLIENT_RECEIVED_ELEMENT);
385 m->element_type = htons (element->type);
386 memcpy (&m[1], element->data, element->size);
387 GNUNET_MQ_send (session->client_mq, ev);
391 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%d: finished iterating elements for client\n",
392 session->local_peer_idx);
393 ev = GNUNET_MQ_msg_header (GNUNET_MESSAGE_TYPE_CONSENSUS_CLIENT_CONCLUDE_DONE);
394 GNUNET_MQ_send (session->client_mq, ev);
401 * Start the next round.
402 * This function can be invoked as a timeout task, or called manually (tc will be NULL then).
404 * @param cls the session
405 * @param tc task context, for when this task is invoked by the scheduler,
406 * NULL if invoked for another reason
409 round_over (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
411 struct ConsensusSession *session;
413 /* don't kick off next round if we're shutting down */
414 if ((NULL != tc) && (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
418 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%d: round over\n", session->local_peer_idx);
420 if (session->round_timeout_tid != GNUNET_SCHEDULER_NO_TASK)
422 GNUNET_SCHEDULER_cancel (session->round_timeout_tid);
423 session->round_timeout_tid = GNUNET_SCHEDULER_NO_TASK;
426 switch (session->current_round)
428 case CONSENSUS_ROUND_BEGIN:
429 session->current_round = CONSENSUS_ROUND_EXCHANGE;
430 session->exp_round = 0;
431 subround_over (session, NULL);
433 case CONSENSUS_ROUND_EXCHANGE:
434 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%d: finished, sending elements to client\n",
435 session->local_peer_idx);
436 session->current_round = CONSENSUS_ROUND_FINISH;
437 GNUNET_SET_iterate (session->element_set, send_to_client_iter, session);
446 * Create a new permutation for the session's peers in session->shuffle.
447 * Uses a Fisher-Yates shuffle with pseudo-randomness coming from
448 * both the global session id and the current round index.
450 * @param session the session to create the new permutation for
453 shuffle (struct ConsensusSession *session)
456 uint32_t randomness[session->num_peers-1];
458 if (NULL == session->shuffle)
459 session->shuffle = GNUNET_malloc (session->num_peers * sizeof (*session->shuffle));
460 if (NULL == session->shuffle_inv)
461 session->shuffle_inv = GNUNET_malloc (session->num_peers * sizeof (*session->shuffle_inv));
463 GNUNET_CRYPTO_kdf (randomness, sizeof (randomness),
464 &session->exp_round, sizeof (uint32_t),
465 &session->global_id, sizeof (struct GNUNET_HashCode),
468 for (i = 0; i < session->num_peers; i++)
469 session->shuffle[i] = i;
471 for (i = session->num_peers - 1; i > 0; i--)
475 x = randomness[i-1] % session->num_peers;
476 tmp = session->shuffle[x];
477 session->shuffle[x] = session->shuffle[i];
478 session->shuffle[i] = tmp;
481 /* create the inverse */
482 for (i = 0; i < session->num_peers; i++)
483 session->shuffle_inv[session->shuffle[i]] = i;
488 * Find and set the partner_incoming and partner_outgoing of our peer,
489 * one of them may not exist (and thus set to NULL) if the number of peers
490 * in the session is not a power of two.
492 * @param session the consensus session
495 find_partners (struct ConsensusSession *session)
498 unsigned int num_ghosts;
499 unsigned int largest_arc;
502 /* shuffled local index */
503 int my_idx = session->shuffle[session->local_peer_idx];
505 /* distance to neighboring peer in current subround */
506 arc = 1 << session->exp_subround;
508 while (largest_arc < session->num_peers)
510 num_ghosts = largest_arc - session->num_peers;
511 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "largest arc: %u\n", largest_arc);
512 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "arc: %u\n", arc);
513 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "num ghosts: %u\n", num_ghosts);
515 if (0 == (my_idx & arc))
517 /* we are outgoing */
518 partner_idx = (my_idx + arc) % session->num_peers;
519 session->partner_outgoing = &session->info[session->shuffle_inv[partner_idx]];
520 session->partner_outgoing->exp_subround_finished = GNUNET_NO;
521 /* are we a 'ghost' of a peer that would exist if
522 * the number of peers was a power of two, and thus have to partner
523 * with an additional peer?
525 if (my_idx < num_ghosts)
527 int ghost_partner_idx;
528 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "my index %d, arc %d, peers %u\n", my_idx, arc, session->num_peers);
529 ghost_partner_idx = (my_idx - (int) arc) % (int) session->num_peers;
530 /* platform dependent; modulo sometimes returns negative values */
531 if (ghost_partner_idx < 0)
532 ghost_partner_idx += session->num_peers;
533 /* we only need to have a ghost partner if the partner is outgoing */
534 if (0 == (ghost_partner_idx & arc))
536 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "ghost partner is %d\n", ghost_partner_idx);
537 session->partner_incoming = &session->info[session->shuffle_inv[ghost_partner_idx]];
538 session->partner_incoming->exp_subround_finished = GNUNET_NO;
542 session->partner_incoming = NULL;
545 /* we only have an incoming connection */
546 partner_idx = (my_idx - (int) arc) % (int) session->num_peers;
548 partner_idx += session->num_peers;
549 session->partner_outgoing = NULL;
550 session->partner_incoming = &session->info[session->shuffle_inv[partner_idx]];
551 session->partner_incoming->exp_subround_finished = GNUNET_NO;
556 * Callback for set operation results. Called for each element
560 * @param element a result element, only valid if status is GNUNET_SET_STATUS_OK
561 * @param status see enum GNUNET_SET_Status
564 set_result_cb (void *cls,
565 const struct GNUNET_SET_Element *element,
566 enum GNUNET_SET_Status status)
568 struct ConsensusPeerInformation *cpi = cls;
569 unsigned int remote_idx = cpi - cpi->session->info;
570 unsigned int local_idx = cpi->session->local_peer_idx;
572 GNUNET_assert ((cpi == cpi->session->partner_outgoing) ||
573 (cpi == cpi->session->partner_incoming));
577 case GNUNET_SET_STATUS_OK:
578 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%u: set result from P%u: element\n",
579 local_idx, remote_idx);
581 case GNUNET_SET_STATUS_FAILURE:
582 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%u: set result from P%u: failure\n",
583 local_idx, remote_idx);
586 case GNUNET_SET_STATUS_HALF_DONE:
587 case GNUNET_SET_STATUS_DONE:
588 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%u: set result from P%u: done\n",
589 local_idx, remote_idx);
590 cpi->exp_subround_finished = GNUNET_YES;
592 if (have_exp_subround_finished (cpi->session) == GNUNET_YES)
594 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%u: all reconciliations of subround done\n",
596 subround_over (cpi->session, NULL);
600 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%u: waiting for further set results\n",
609 switch (cpi->session->current_round)
611 case CONSENSUS_ROUND_EXCHANGE:
612 GNUNET_SET_add_element (cpi->session->element_set, element, NULL, NULL);
622 * Compare the round the session is in with the round of the given context message.
624 * @param session a consensus session
625 * @param ri a round context message
626 * @return 0 if it's the same round, -1 if the session is in an earlier round,
627 * 1 if the session is in a later round
630 rounds_compare (struct ConsensusSession *session,
631 struct RoundInfo* ri)
633 if (session->current_round < ri->round)
635 if (session->current_round > ri->round)
637 if (session->current_round == CONSENSUS_ROUND_EXCHANGE)
639 if (session->exp_round < ri->exp_round)
641 if (session->exp_round > ri->exp_round)
643 if (session->exp_subround < ri->exp_subround)
645 if (session->exp_subround < ri->exp_subround)
649 /* comparing rounds when we are not in a exp round */
655 * Do the next subround in the exp-scheme.
656 * This function can be invoked as a timeout task, or called manually (tc will be NULL then).
658 * @param cls the session
659 * @param tc task context, for when this task is invoked by the scheduler,
660 * NULL if invoked for another reason
663 subround_over (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
665 struct ConsensusSession *session;
668 /* don't kick off next subround if we're shutting down */
669 if ((NULL != tc) && (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
673 if (session->round_timeout_tid != GNUNET_SCHEDULER_NO_TASK)
675 GNUNET_SCHEDULER_cancel (session->round_timeout_tid);
676 session->round_timeout_tid = GNUNET_SCHEDULER_NO_TASK;
679 if (session->exp_round >= NUM_EXP_ROUNDS)
681 round_over (session, NULL);
685 if (session->exp_round == 0)
687 /* initialize everything for the log-rounds */
688 session->exp_round = 1;
689 session->exp_subround = 0;
690 if (NULL == session->shuffle)
691 session->shuffle = GNUNET_malloc ((sizeof (int)) * session->num_peers);
692 if (NULL == session->shuffle_inv)
693 session->shuffle_inv = GNUNET_malloc ((sizeof (int)) * session->num_peers);
694 for (i = 0; i < session->num_peers; i++)
695 session->shuffle[i] = session->shuffle_inv[i] = i;
697 else if (session->exp_subround + 1 >= (int) ceil (log2 (session->num_peers)))
699 /* subrounds done, start new log-round */
700 session->exp_round++;
701 session->exp_subround = 0;
706 session->exp_subround++;
709 /* determine the incoming and outgoing partner */
710 find_partners (session);
712 GNUNET_assert (session->partner_outgoing != &session->info[session->local_peer_idx]);
713 GNUNET_assert (session->partner_incoming != &session->info[session->local_peer_idx]);
715 /* initiate set operation with the outgoing partner */
716 if (NULL != session->partner_outgoing)
718 struct GNUNET_CONSENSUS_RoundContextMessage *msg;
719 msg = GNUNET_new (struct GNUNET_CONSENSUS_RoundContextMessage);
720 msg->header.type = htons (GNUNET_MESSAGE_TYPE_CONSENSUS_P2P_ROUND_CONTEXT);
721 msg->header.size = htons (sizeof *msg);
722 msg->round = htonl (session->current_round);
723 msg->exp_round = htonl (session->exp_round);
724 msg->exp_subround = htonl (session->exp_subround);
726 if (NULL != session->partner_outgoing->set_op)
728 GNUNET_SET_operation_cancel (session->partner_outgoing->set_op);
730 session->partner_outgoing->set_op =
731 GNUNET_SET_prepare (&session->partner_outgoing->peer_id,
733 (struct GNUNET_MessageHeader *) msg,
735 GNUNET_SET_RESULT_ADDED,
736 set_result_cb, session->partner_outgoing);
738 GNUNET_SET_commit (session->partner_outgoing->set_op, session->element_set);
741 /* commit to the delayed set operation */
742 if ((NULL != session->partner_incoming) && (NULL != session->partner_incoming->delayed_set_op))
744 int cmp = rounds_compare (session, &session->partner_incoming->delayed_round_info);
746 if (NULL != session->partner_incoming->set_op)
748 GNUNET_SET_operation_cancel (session->partner_incoming->set_op);
749 session->partner_incoming->set_op = NULL;
753 GNUNET_SET_commit (session->partner_incoming->delayed_set_op, session->element_set);
754 session->partner_incoming->set_op = session->partner_incoming->delayed_set_op;
755 session->partner_incoming->delayed_set_op = NULL;
756 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%d resumed delayed round with P%d\n",
757 session->local_peer_idx, (int) (session->partner_incoming - session->info));
761 /* this should not happen -- a round has been skipped! */
766 #ifdef GNUNET_EXTRA_LOGGING
770 if (session->partner_outgoing == NULL)
773 out = (int) (session->partner_outgoing - session->info);
774 if (session->partner_incoming == NULL)
777 in = (int) (session->partner_incoming - session->info);
778 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%u: doing exp-round, r=%d, sub=%d, in: %d, out: %d\n", session->local_peer_idx,
779 session->exp_round, session->exp_subround, in, out);
781 #endif /* GNUNET_EXTRA_LOGGING */
787 * Search peer in the list of peers in session.
789 * @param peer peer to find
790 * @param session session with peer
791 * @return index of peer, -1 if peer is not in session
794 get_peer_idx (const struct GNUNET_PeerIdentity *peer, const struct ConsensusSession *session)
797 for (i = 0; i < session->num_peers; i++)
798 if (0 == memcmp (peer, &session->info[i].peer_id, sizeof *peer))
805 * Compute a global, (hopefully) unique consensus session id,
806 * from the local id of the consensus session, and the identities of all participants.
807 * Thus, if the local id of two consensus sessions coincide, but are not comprised of
808 * exactly the same peers, the global id will be different.
810 * @param session session to generate the global id for
811 * @param session_id local id of the consensus session
814 compute_global_id (struct ConsensusSession *session, const struct GNUNET_HashCode *session_id)
817 struct GNUNET_HashCode tmp;
819 /* FIXME: use kdf? */
821 session->global_id = *session_id;
822 for (i = 0; i < session->num_peers; ++i)
824 GNUNET_CRYPTO_hash_xor (&session->global_id, &session->info[i].peer_id.hashPubKey, &tmp);
825 session->global_id = tmp;
826 GNUNET_CRYPTO_hash (&session->global_id, sizeof (struct GNUNET_PeerIdentity), &tmp);
827 session->global_id = tmp;
833 * Although GNUNET_CRYPTO_hash_cmp exisits, it does not have
834 * the correct signature to be used with e.g. qsort.
835 * We use this function instead.
837 * @param h1 some hash code
838 * @param h2 some hash code
839 * @return 1 if h1 > h2, -1 if h1 < h2 and 0 if h1 == h2.
842 hash_cmp (const void *h1, const void *h2)
844 return GNUNET_CRYPTO_hash_cmp ((struct GNUNET_HashCode *) h1, (struct GNUNET_HashCode *) h2);
849 * Create the sorted list of peers for the session,
850 * add the local peer if not in the join message.
853 initialize_session_peer_list (struct ConsensusSession *session,
854 struct GNUNET_CONSENSUS_JoinMessage *join_msg)
856 unsigned int local_peer_in_list;
857 uint32_t listed_peers;
858 const struct GNUNET_PeerIdentity *msg_peers;
859 struct GNUNET_PeerIdentity *peers;
862 GNUNET_assert (NULL != join_msg);
864 /* peers in the join message, may or may not include the local peer */
865 listed_peers = ntohl (join_msg->num_peers);
867 session->num_peers = listed_peers;
869 msg_peers = (struct GNUNET_PeerIdentity *) &join_msg[1];
871 local_peer_in_list = GNUNET_NO;
872 for (i = 0; i < listed_peers; i++)
874 if (0 == memcmp (&msg_peers[i], &my_peer, sizeof (struct GNUNET_PeerIdentity)))
876 local_peer_in_list = GNUNET_YES;
881 if (GNUNET_NO == local_peer_in_list)
882 session->num_peers++;
884 peers = GNUNET_malloc (session->num_peers * sizeof (struct GNUNET_PeerIdentity));
886 if (GNUNET_NO == local_peer_in_list)
887 peers[session->num_peers - 1] = my_peer;
889 memcpy (peers, msg_peers, listed_peers * sizeof (struct GNUNET_PeerIdentity));
890 qsort (peers, session->num_peers, sizeof (struct GNUNET_PeerIdentity), &hash_cmp);
892 session->info = GNUNET_malloc (session->num_peers * sizeof (struct ConsensusPeerInformation));
894 for (i = 0; i < session->num_peers; ++i)
896 /* initialize back-references, so consensus peer information can
897 * be used as closure */
898 session->info[i].session = session;
899 session->info[i].peer_id = peers[i];
907 * Called when another peer wants to do a set operation with the
911 * @param other_peer the other peer
912 * @param context_msg message with application specific information from
914 * @param request request from the other peer, use GNUNET_SET_accept
915 * to accept it, otherwise the request will be refused
916 * Note that we don't use a return value here, as it is also
917 * necessary to specify the set we want to do the operation with,
918 * whith sometimes can be derived from the context message.
919 * Also necessary to specify the timeout.
922 set_listen_cb (void *cls,
923 const struct GNUNET_PeerIdentity *other_peer,
924 const struct GNUNET_MessageHeader *context_msg,
925 struct GNUNET_SET_Request *request)
927 struct ConsensusSession *session = cls;
928 struct GNUNET_CONSENSUS_RoundContextMessage *msg = (struct GNUNET_CONSENSUS_RoundContextMessage *) context_msg;
929 struct ConsensusPeerInformation *cpi;
930 struct GNUNET_SET_OperationHandle *set_op;
931 struct RoundInfo round_info;
935 if (NULL == context_msg)
941 index = get_peer_idx (other_peer, session);
949 round_info.round = ntohl (msg->round);
950 round_info.exp_round = ntohl (msg->exp_round);
951 round_info.exp_subround = ntohl (msg->exp_subround);
953 cpi = &session->info[index];
955 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%d got set request from P%d\n", session->local_peer_idx, index);
957 switch (session->current_round)
959 case CONSENSUS_ROUND_BEGIN:
960 /* we're in the begin round, so requests for the exchange round may
961 * come in, they will be delayed for now! */
962 case CONSENSUS_ROUND_EXCHANGE:
963 cmp = rounds_compare (session, &round_info);
966 /* the other peer is too late */
970 /* kill old request, if any. this is legal,
971 * as the other peer would not make a new request if it would want to
972 * complete the old one! */
973 if (NULL != cpi->set_op)
975 GNUNET_SET_operation_cancel (cpi->set_op);
978 set_op = GNUNET_SET_accept (request, GNUNET_SET_RESULT_ADDED,
979 set_result_cb, &session->info[index]);
982 cpi->set_op = set_op;
983 GNUNET_SET_commit (set_op, session->element_set);
984 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%d commited to set request from P%d\n", session->local_peer_idx, index);
988 /* if there's a exp subround running, mark it as finished, as the set op has been canceled! */
989 cpi->delayed_set_op = set_op;
990 cpi->delayed_round_info = round_info;
991 cpi->exp_subround_finished = GNUNET_YES;
992 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%d delaying set request from P%d\n", session->local_peer_idx, index);
996 GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "P%d got unexpected set request in round %d from P%d\n",
997 session->local_peer_idx, session->current_round, index);
1005 * Initialize the session, continue receiving messages from the owning client
1007 * @param session the session to initialize
1008 * @param join_msg the join message from the client
1011 initialize_session (struct ConsensusSession *session,
1012 struct GNUNET_CONSENSUS_JoinMessage *join_msg)
1014 struct ConsensusSession *other_session;
1016 initialize_session_peer_list (session, join_msg);
1017 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "session with %u peers\n", session->num_peers);
1018 compute_global_id (session, &join_msg->session_id);
1020 /* check if some local client already owns the session.
1021 * it is only legal to have a session with an existing global id
1022 * if all other sessions with this global id are finished.*/
1023 other_session = sessions_head;
1024 while (NULL != other_session)
1026 if ((other_session != session) &&
1027 (0 == GNUNET_CRYPTO_hash_cmp (&session->global_id, &other_session->global_id)))
1029 if (CONSENSUS_ROUND_FINISH != other_session->current_round)
1032 destroy_session (session);
1037 other_session = other_session->next;
1040 session->local_peer_idx = get_peer_idx (&my_peer, session);
1041 GNUNET_assert (-1 != session->local_peer_idx);
1042 session->element_set = GNUNET_SET_create (cfg, GNUNET_SET_OPERATION_UNION);
1043 GNUNET_assert (NULL != session->element_set);
1044 session->set_listener = GNUNET_SET_listen (cfg, GNUNET_SET_OPERATION_UNION,
1045 &session->global_id,
1046 set_listen_cb, session);
1047 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "%d is the local peer\n", session->local_peer_idx);
1048 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "session %s initialized\n", GNUNET_h2s (&session->global_id));
1052 static struct ConsensusSession *
1053 get_session_by_client (struct GNUNET_SERVER_Client *client)
1055 struct ConsensusSession *session;
1057 session = sessions_head;
1058 while (NULL != session)
1060 if (session->client == client)
1062 session = session->next;
1069 * Called when a client wants to join a consensus session.
1072 * @param client client that sent the message
1073 * @param m message sent by the client
1076 client_join (void *cls,
1077 struct GNUNET_SERVER_Client *client,
1078 const struct GNUNET_MessageHeader *m)
1080 struct ConsensusSession *session;
1082 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "join message sent by client\n");
1084 session = get_session_by_client (client);
1085 if (NULL != session)
1088 GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
1091 session = GNUNET_new (struct ConsensusSession);
1092 session->client = client;
1093 session->client_mq = GNUNET_MQ_queue_for_server_client (client);
1094 GNUNET_CONTAINER_DLL_insert (sessions_head, sessions_tail, session);
1095 initialize_session (session, (struct GNUNET_CONSENSUS_JoinMessage *) m);
1096 GNUNET_SERVER_receive_done (client, GNUNET_OK);
1098 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "join done\n");
1103 * Called when a client performs an insert operation.
1105 * @param cls (unused)
1106 * @param client client handle
1107 * @param m message sent by the client
1110 client_insert (void *cls,
1111 struct GNUNET_SERVER_Client *client,
1112 const struct GNUNET_MessageHeader *m)
1114 struct ConsensusSession *session;
1115 struct GNUNET_CONSENSUS_ElementMessage *msg;
1116 struct GNUNET_SET_Element *element;
1117 ssize_t element_size;
1119 session = get_session_by_client (client);
1121 if (NULL == session)
1124 GNUNET_SERVER_client_disconnect (client);
1128 if (CONSENSUS_ROUND_BEGIN != session->current_round)
1131 GNUNET_SERVER_client_disconnect (client);
1135 msg = (struct GNUNET_CONSENSUS_ElementMessage *) m;
1136 element_size = ntohs (msg->header.size) - sizeof (struct GNUNET_CONSENSUS_ElementMessage);
1137 if (element_size < 0)
1143 element = GNUNET_malloc (sizeof (struct GNUNET_SET_Element) + element_size);
1144 element->type = msg->element_type;
1145 element->size = element_size;
1146 memcpy (&element[1], &msg[1], element_size);
1147 element->data = &element[1];
1148 GNUNET_SET_add_element (session->element_set, element, NULL, NULL);
1149 GNUNET_free (element);
1150 GNUNET_SERVER_receive_done (client, GNUNET_OK);
1152 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%u: element added\n", session->local_peer_idx);
1157 * Called when a client performs the conclude operation.
1159 * @param cls (unused)
1160 * @param client client handle
1161 * @param message message sent by the client
1164 client_conclude (void *cls,
1165 struct GNUNET_SERVER_Client *client,
1166 const struct GNUNET_MessageHeader *message)
1168 struct ConsensusSession *session;
1169 struct GNUNET_CONSENSUS_ConcludeMessage *cmsg;
1172 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "conclude requested\n");
1173 cmsg = (struct GNUNET_CONSENSUS_ConcludeMessage *) message;
1174 session = get_session_by_client (client);
1175 if (NULL == session)
1177 /* client not found */
1179 GNUNET_SERVER_client_disconnect (client);
1182 if (CONSENSUS_ROUND_BEGIN != session->current_round)
1184 /* client requested conclude twice */
1188 if (session->num_peers <= 1)
1190 session->current_round = CONSENSUS_ROUND_FINISH;
1191 GNUNET_SET_iterate (session->element_set, send_to_client_iter, session);
1195 session->conclude_timeout = GNUNET_TIME_relative_ntoh (cmsg->timeout);
1196 /* the 'begin' round is over, start with the next, actual round */
1197 round_over (session, NULL);
1200 GNUNET_assert (CONSENSUS_ROUND_BEGIN != session->current_round);
1201 GNUNET_SERVER_receive_done (client, GNUNET_OK);
1206 * Called to clean up, after a shutdown has been requested.
1208 * @param cls closure
1209 * @param tc context information (why was this task triggered now)
1212 shutdown_task (void *cls,
1213 const struct GNUNET_SCHEDULER_TaskContext *tc)
1215 while (NULL != sessions_head)
1216 destroy_session (sessions_head);
1218 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "handled shutdown request\n");
1223 * Clean up after a client after it is
1224 * disconnected (either by us or by itself)
1226 * @param cls closure, unused
1227 * @param client the client to clean up after
1230 handle_client_disconnect (void *cls, struct GNUNET_SERVER_Client *client)
1232 struct ConsensusSession *session;
1234 session = get_session_by_client (client);
1235 if (NULL == session)
1237 if ((CONSENSUS_ROUND_BEGIN == session->current_round) ||
1238 (CONSENSUS_ROUND_FINISH == session->current_round))
1239 destroy_session (session);
1241 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "client disconnected, but waiting for consensus to finish\n");
1246 * Start processing consensus requests.
1248 * @param cls closure
1249 * @param server the initialized server
1250 * @param c configuration to use
1253 run (void *cls, struct GNUNET_SERVER_Handle *server,
1254 const struct GNUNET_CONFIGURATION_Handle *c)
1256 static const struct GNUNET_SERVER_MessageHandler server_handlers[] = {
1257 {&client_conclude, NULL, GNUNET_MESSAGE_TYPE_CONSENSUS_CLIENT_CONCLUDE,
1258 sizeof (struct GNUNET_CONSENSUS_ConcludeMessage)},
1259 {&client_insert, NULL, GNUNET_MESSAGE_TYPE_CONSENSUS_CLIENT_INSERT, 0},
1260 {&client_join, NULL, GNUNET_MESSAGE_TYPE_CONSENSUS_CLIENT_JOIN, 0},
1266 if (GNUNET_OK != GNUNET_CRYPTO_get_host_identity (cfg, &my_peer))
1268 GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "could not retrieve host identity\n");
1270 GNUNET_SCHEDULER_shutdown ();
1273 GNUNET_SERVER_add_handlers (server, server_handlers);
1274 GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL, &shutdown_task, NULL);
1275 GNUNET_SERVER_disconnect_notify (server, handle_client_disconnect, NULL);
1276 GNUNET_log (GNUNET_ERROR_TYPE_INFO, "consensus running\n");
1281 * The main function for the consensus service.
1283 * @param argc number of arguments from the command line
1284 * @param argv command line arguments
1285 * @return 0 ok, 1 on error
1288 main (int argc, char *const *argv)
1291 ret = GNUNET_SERVICE_run (argc, argv, "consensus", GNUNET_SERVICE_OPTION_NONE, &run, NULL);
1292 GNUNET_log (GNUNET_ERROR_TYPE_INFO, "exit (%d)\n", GNUNET_OK != ret);
1293 return (GNUNET_OK == ret) ? 0 : 1;