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 2, 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,
180 * maps logical index (for current round) to physical index (location in info array)
185 * Current round of the exponential scheme.
190 * Current sub-round of the exponential scheme.
192 uint32_t exp_subround;
195 * The partner for the current exp-round
197 struct ConsensusPeerInformation *partner_outgoing;
200 * The partner for the current exp-round
202 struct ConsensusPeerInformation *partner_incoming;
205 * The consensus set of this session.
207 struct GNUNET_SET_Handle *element_set;
210 * Listener for requests from other peers.
211 * Uses the session's global id as app id.
213 struct GNUNET_SET_ListenHandle *set_listener;
218 * Information about a peer that is in a consensus session.
220 struct ConsensusPeerInformation
223 * Peer identitty of the peer in the consensus session
225 struct GNUNET_PeerIdentity peer_id;
228 * Back-reference to the consensus session,
229 * to that ConsensusPeerInformation can be used as a closure
231 struct ConsensusSession *session;
234 * We have finishes the exp-subround with the peer.
236 int exp_subround_finished;
239 * Set operation we are currently executing with this peer.
241 struct GNUNET_SET_OperationHandle *set_op;
244 * Set operation we are planning on executing with this peer.
246 struct GNUNET_SET_OperationHandle *delayed_set_op;
249 * Info about the round of the delayed set operation.
251 struct RoundInfo delayed_round_info;
256 * Linked list of sessions this peer participates in.
258 static struct ConsensusSession *sessions_head;
261 * Linked list of sessions this peer participates in.
263 static struct ConsensusSession *sessions_tail;
266 * Configuration of the consensus service.
268 static const struct GNUNET_CONFIGURATION_Handle *cfg;
271 * Handle to the server for this service.
273 static struct GNUNET_SERVER_Handle *srv;
276 * Peer that runs this service.
278 static struct GNUNET_PeerIdentity my_peer;
282 have_exp_subround_finished (const struct ConsensusSession *session)
286 if ( (NULL != session->partner_outgoing) &&
287 (GNUNET_NO == session->partner_outgoing->exp_subround_finished) )
289 if ( (NULL != session->partner_incoming) &&
290 (GNUNET_NO == session->partner_incoming->exp_subround_finished) )
292 if (0 == not_finished)
299 * Destroy a session, free all resources associated with it.
301 * @param session the session to destroy
304 destroy_session (struct ConsensusSession *session)
308 GNUNET_CONTAINER_DLL_remove (sessions_head, sessions_tail, session);
309 if (NULL != session->element_set)
311 GNUNET_SET_destroy (session->element_set);
312 session->element_set = NULL;
314 if (NULL != session->set_listener)
316 GNUNET_SET_listen_cancel (session->set_listener);
317 session->set_listener = NULL;
319 if (NULL != session->client_mq)
321 GNUNET_MQ_destroy (session->client_mq);
322 session->client_mq = NULL;
324 if (NULL != session->client)
326 GNUNET_SERVER_client_disconnect (session->client);
327 session->client = NULL;
329 if (NULL != session->shuffle)
331 GNUNET_free (session->shuffle);
332 session->shuffle = NULL;
334 if (NULL != session->info)
336 for (i = 0; i < session->num_peers; i++)
338 struct ConsensusPeerInformation *cpi;
339 cpi = &session->info[i];
340 if (NULL != cpi->set_op)
342 GNUNET_SET_operation_cancel (cpi->set_op);
346 GNUNET_free (session->info);
347 session->info = NULL;
349 GNUNET_free (session);
354 * Iterator for set elements.
357 * @param element the current element, NULL if all elements have been
359 * @return GNUNET_YES to continue iterating, GNUNET_NO to stop.
362 send_to_client_iter (void *cls,
363 const struct GNUNET_SET_Element *element)
365 struct ConsensusSession *session = cls;
366 struct GNUNET_MQ_Envelope *ev;
370 struct GNUNET_CONSENSUS_ElementMessage *m;
372 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%d: got element for client\n",
373 session->local_peer_idx);
375 ev = GNUNET_MQ_msg_extra (m, element->size, GNUNET_MESSAGE_TYPE_CONSENSUS_CLIENT_RECEIVED_ELEMENT);
376 m->element_type = htons (element->type);
377 memcpy (&m[1], element->data, element->size);
378 GNUNET_MQ_send (session->client_mq, ev);
382 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%d: finished iterating elements for client\n",
383 session->local_peer_idx);
384 ev = GNUNET_MQ_msg_header (GNUNET_MESSAGE_TYPE_CONSENSUS_CLIENT_CONCLUDE_DONE);
385 GNUNET_MQ_send (session->client_mq, ev);
392 * Start the next round.
393 * This function can be invoked as a timeout task, or called manually (tc will be NULL then).
395 * @param cls the session
396 * @param tc task context, for when this task is invoked by the scheduler,
397 * NULL if invoked for another reason
400 round_over (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
402 struct ConsensusSession *session;
404 /* don't kick off next round if we're shutting down */
405 if ((NULL != tc) && (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
409 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%d: round over\n", session->local_peer_idx);
411 if (session->round_timeout_tid != GNUNET_SCHEDULER_NO_TASK)
413 GNUNET_SCHEDULER_cancel (session->round_timeout_tid);
414 session->round_timeout_tid = GNUNET_SCHEDULER_NO_TASK;
417 switch (session->current_round)
419 case CONSENSUS_ROUND_BEGIN:
420 session->current_round = CONSENSUS_ROUND_EXCHANGE;
421 session->exp_round = 0;
422 subround_over (session, NULL);
424 case CONSENSUS_ROUND_EXCHANGE:
425 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%d: finished, sending elements to client\n",
426 session->local_peer_idx);
427 session->current_round = CONSENSUS_ROUND_FINISH;
428 GNUNET_SET_iterate (session->element_set, send_to_client_iter, session);
437 * Create a new permutation for the session's peers in session->shuffle.
438 * Uses a Fisher-Yates shuffle with pseudo-randomness coming from
439 * both the global session id and the current round index.
441 * @param session the session to create the new permutation for
444 shuffle (struct ConsensusSession *session)
447 uint32_t randomness[session->num_peers-1];
449 if (NULL == session->shuffle)
450 session->shuffle = GNUNET_malloc (session->num_peers * sizeof (*session->shuffle));
452 GNUNET_CRYPTO_kdf (randomness, sizeof (randomness),
453 &session->exp_round, sizeof (uint32_t),
454 &session->global_id, sizeof (struct GNUNET_HashCode),
457 for (i = 0; i < session->num_peers; i++)
458 session->shuffle[i] = i;
460 for (i = session->num_peers - 1; i > 0; i--)
464 x = randomness[i-1] % session->num_peers;
465 tmp = session->shuffle[x];
466 session->shuffle[x] = session->shuffle[i];
467 session->shuffle[i] = tmp;
473 * Find and set the partner_incoming and partner_outgoing of our peer,
474 * one of them may not exist (and thus set to NULL) if the number of peers
475 * in the session is not a power of two.
477 * @param session the consensus session
480 find_partners (struct ConsensusSession *session)
483 unsigned int num_ghosts;
484 unsigned int largest_arc;
487 /* shuffled local index */
488 int my_idx = session->shuffle[session->local_peer_idx];
490 /* distance to neighboring peer in current subround */
491 arc = 1 << session->exp_subround;
493 while (largest_arc < session->num_peers)
495 num_ghosts = largest_arc - session->num_peers;
497 if (0 == (my_idx & arc))
499 /* we are outgoing */
500 partner_idx = (my_idx + arc) % session->num_peers;
501 session->partner_outgoing = &session->info[session->shuffle[partner_idx]];
502 session->partner_outgoing->exp_subround_finished = GNUNET_NO;
503 /* are we a 'ghost' of a peer that would exist if
504 * the number of peers was a power of two, and thus have to partner
505 * with an additional peer?
507 if (my_idx < num_ghosts)
509 int ghost_partner_idx;
510 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "my index %d, arc %d, peers %u\n", my_idx, arc, session->num_peers);
511 ghost_partner_idx = (my_idx - (int) arc) % (int) session->num_peers;
512 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "ghost partner is before %d\n", ghost_partner_idx);
513 /* platform dependent; modulo sometimes returns negative values */
514 if (ghost_partner_idx < 0)
515 ghost_partner_idx += session->num_peers;
516 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "ghost partner is after %d\n", ghost_partner_idx);
517 session->partner_incoming = &session->info[session->shuffle[ghost_partner_idx]];
518 session->partner_incoming->exp_subround_finished = GNUNET_NO;
521 session->partner_incoming = NULL;
524 partner_idx = (my_idx - (int) arc) % (int) session->num_peers;
526 partner_idx += session->num_peers;
527 session->partner_outgoing = NULL;
528 session->partner_incoming = &session->info[session->shuffle[partner_idx]];
529 session->partner_incoming->exp_subround_finished = GNUNET_NO;
534 * Callback for set operation results. Called for each element
538 * @param element a result element, only valid if status is GNUNET_SET_STATUS_OK
539 * @param status see enum GNUNET_SET_Status
542 set_result_cb (void *cls,
543 const struct GNUNET_SET_Element *element,
544 enum GNUNET_SET_Status status)
546 struct ConsensusPeerInformation *cpi = cls;
547 unsigned int remote_idx = cpi - cpi->session->info;
548 unsigned int local_idx = cpi->session->local_peer_idx;
550 GNUNET_assert ((cpi == cpi->session->partner_outgoing) ||
551 (cpi == cpi->session->partner_incoming));
555 case GNUNET_SET_STATUS_OK:
556 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%u: set result from P%u: element\n",
557 local_idx, remote_idx);
559 case GNUNET_SET_STATUS_FAILURE:
560 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%u: set result from P%u: failure\n",
561 local_idx, remote_idx);
564 case GNUNET_SET_STATUS_HALF_DONE:
565 case GNUNET_SET_STATUS_DONE:
566 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%u: set result from P%u: done\n",
567 local_idx, remote_idx);
568 cpi->exp_subround_finished = GNUNET_YES;
570 if (have_exp_subround_finished (cpi->session) == GNUNET_YES)
572 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%u: all reconciliations of subround done\n",
574 subround_over (cpi->session, NULL);
578 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%u: waiting for further set results\n",
587 switch (cpi->session->current_round)
589 case CONSENSUS_ROUND_EXCHANGE:
590 GNUNET_SET_add_element (cpi->session->element_set, element, NULL, NULL);
600 * Compare the round the session is in with the round of the given context message.
602 * @param session a consensus session
603 * @param round a round context message
604 * @return 0 if it's the same round, -1 if the session is in an earlier round,
605 * 1 if the session is in a later round
608 rounds_compare (struct ConsensusSession *session,
609 struct RoundInfo* ri)
611 if (session->current_round < ri->round)
613 if (session->current_round > ri->round)
615 if (session->current_round == CONSENSUS_ROUND_EXCHANGE)
617 if (session->exp_round < ri->exp_round)
619 if (session->exp_round > ri->exp_round)
621 if (session->exp_subround < ri->exp_subround)
623 if (session->exp_subround < ri->exp_subround)
627 /* comparing rounds when we are not in a exp round */
633 * Do the next subround in the exp-scheme.
634 * This function can be invoked as a timeout task, or called manually (tc will be NULL then).
636 * @param cls the session
637 * @param tc task context, for when this task is invoked by the scheduler,
638 * NULL if invoked for another reason
641 subround_over (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
643 struct ConsensusSession *session;
646 /* don't kick off next subround if we're shutting down */
647 if ((NULL != tc) && (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
651 if (session->round_timeout_tid != GNUNET_SCHEDULER_NO_TASK)
653 GNUNET_SCHEDULER_cancel (session->round_timeout_tid);
654 session->round_timeout_tid = GNUNET_SCHEDULER_NO_TASK;
657 if (session->exp_round >= NUM_EXP_ROUNDS)
659 round_over (session, NULL);
663 if (session->exp_round == 0)
665 /* initialize everything for the log-rounds */
666 session->exp_round = 1;
667 session->exp_subround = 0;
668 if (NULL == session->shuffle)
669 session->shuffle = GNUNET_malloc ((sizeof (int)) * session->num_peers);
670 for (i = 0; i < session->num_peers; i++)
671 session->shuffle[i] = i;
673 else if (session->exp_subround + 1 >= (int) ceil (log2 (session->num_peers)))
675 /* subrounds done, start new log-round */
676 session->exp_round++;
677 session->exp_subround = 0;
682 session->exp_subround++;
685 /* determine the incoming and outgoing partner */
686 find_partners (session);
688 GNUNET_assert (session->partner_outgoing != &session->info[session->local_peer_idx]);
689 GNUNET_assert (session->partner_incoming != &session->info[session->local_peer_idx]);
691 /* initiate set operation with the outgoing partner */
692 if (NULL != session->partner_outgoing)
694 struct GNUNET_CONSENSUS_RoundContextMessage *msg;
695 msg = GNUNET_new (struct GNUNET_CONSENSUS_RoundContextMessage);
696 msg->header.type = htons (GNUNET_MESSAGE_TYPE_CONSENSUS_P2P_ROUND_CONTEXT);
697 msg->header.size = htons (sizeof *msg);
698 msg->round = htonl (session->current_round);
699 msg->exp_round = htonl (session->exp_round);
700 msg->exp_subround = htonl (session->exp_subround);
702 if (NULL != session->partner_outgoing->set_op)
704 GNUNET_SET_operation_cancel (session->partner_outgoing->set_op);
706 session->partner_outgoing->set_op =
707 GNUNET_SET_prepare (&session->partner_outgoing->peer_id,
709 (struct GNUNET_MessageHeader *) msg,
711 GNUNET_SET_RESULT_ADDED,
712 set_result_cb, session->partner_outgoing);
714 GNUNET_SET_commit (session->partner_outgoing->set_op, session->element_set);
717 /* commit to the delayed set operation */
718 if ((NULL != session->partner_incoming) && (NULL != session->partner_incoming->delayed_set_op))
720 int cmp = rounds_compare (session, &session->partner_incoming->delayed_round_info);
722 if (NULL != session->partner_incoming->set_op)
724 GNUNET_SET_operation_cancel (session->partner_incoming->set_op);
725 session->partner_incoming->set_op = NULL;
729 GNUNET_SET_commit (session->partner_incoming->delayed_set_op, session->element_set);
730 session->partner_incoming->set_op = session->partner_incoming->delayed_set_op;
731 session->partner_incoming->delayed_set_op = NULL;
732 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%d resumed delayed round with P%d\n",
733 session->local_peer_idx, (int) (session->partner_incoming - session->info));
737 /* this should not happen -- a round has been skipped! */
742 #ifdef GNUNET_EXTRA_LOGGING
746 if (session->partner_outgoing == NULL)
749 out = (int) (session->partner_outgoing - session->info);
750 if (session->partner_incoming == NULL)
753 in = (int) (session->partner_incoming - session->info);
754 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%u: doing exp-round, r=%d, sub=%d, in: %d, out: %d\n", session->local_peer_idx,
755 session->exp_round, session->exp_subround, in, out);
757 #endif /* GNUNET_EXTRA_LOGGING */
763 * Search peer in the list of peers in session.
765 * @param peer peer to find
766 * @param session session with peer
767 * @return index of peer, -1 if peer is not in session
770 get_peer_idx (const struct GNUNET_PeerIdentity *peer, const struct ConsensusSession *session)
773 for (i = 0; i < session->num_peers; i++)
774 if (0 == memcmp (peer, &session->info[i].peer_id, sizeof *peer))
781 * Compute a global, (hopefully) unique consensus session id,
782 * from the local id of the consensus session, and the identities of all participants.
783 * Thus, if the local id of two consensus sessions coincide, but are not comprised of
784 * exactly the same peers, the global id will be different.
786 * @param session session to generate the global id for
787 * @param session_id local id of the consensus session
790 compute_global_id (struct ConsensusSession *session, const struct GNUNET_HashCode *session_id)
793 struct GNUNET_HashCode tmp;
795 /* FIXME: use kdf? */
797 session->global_id = *session_id;
798 for (i = 0; i < session->num_peers; ++i)
800 GNUNET_CRYPTO_hash_xor (&session->global_id, &session->info[i].peer_id.hashPubKey, &tmp);
801 session->global_id = tmp;
802 GNUNET_CRYPTO_hash (&session->global_id, sizeof (struct GNUNET_PeerIdentity), &tmp);
803 session->global_id = tmp;
809 * Although GNUNET_CRYPTO_hash_cmp exisits, it does not have
810 * the correct signature to be used with e.g. qsort.
811 * We use this function instead.
813 * @param h1 some hash code
814 * @param h2 some hash code
815 * @return 1 if h1 > h2, -1 if h1 < h2 and 0 if h1 == h2.
818 hash_cmp (const void *h1, const void *h2)
820 return GNUNET_CRYPTO_hash_cmp ((struct GNUNET_HashCode *) h1, (struct GNUNET_HashCode *) h2);
825 * Create the sorted list of peers for the session,
826 * add the local peer if not in the join message.
829 initialize_session_peer_list (struct ConsensusSession *session,
830 struct GNUNET_CONSENSUS_JoinMessage *join_msg)
832 unsigned int local_peer_in_list;
833 uint32_t listed_peers;
834 const struct GNUNET_PeerIdentity *msg_peers;
835 struct GNUNET_PeerIdentity *peers;
838 GNUNET_assert (NULL != join_msg);
840 /* peers in the join message, may or may not include the local peer */
841 listed_peers = ntohl (join_msg->num_peers);
843 session->num_peers = listed_peers;
845 msg_peers = (struct GNUNET_PeerIdentity *) &join_msg[1];
847 local_peer_in_list = GNUNET_NO;
848 for (i = 0; i < listed_peers; i++)
850 if (0 == memcmp (&msg_peers[i], &my_peer, sizeof (struct GNUNET_PeerIdentity)))
852 local_peer_in_list = GNUNET_YES;
857 if (GNUNET_NO == local_peer_in_list)
858 session->num_peers++;
860 peers = GNUNET_malloc (session->num_peers * sizeof (struct GNUNET_PeerIdentity));
862 if (GNUNET_NO == local_peer_in_list)
863 peers[session->num_peers - 1] = my_peer;
865 memcpy (peers, msg_peers, listed_peers * sizeof (struct GNUNET_PeerIdentity));
866 qsort (peers, session->num_peers, sizeof (struct GNUNET_PeerIdentity), &hash_cmp);
868 session->info = GNUNET_malloc (session->num_peers * sizeof (struct ConsensusPeerInformation));
870 for (i = 0; i < session->num_peers; ++i)
872 /* initialize back-references, so consensus peer information can
873 * be used as closure */
874 session->info[i].session = session;
875 session->info[i].peer_id = peers[i];
883 * Called when another peer wants to do a set operation with the
887 * @param other_peer the other peer
888 * @param context_msg message with application specific information from
890 * @param request request from the other peer, use GNUNET_SET_accept
891 * to accept it, otherwise the request will be refused
892 * Note that we don't use a return value here, as it is also
893 * necessary to specify the set we want to do the operation with,
894 * whith sometimes can be derived from the context message.
895 * Also necessary to specify the timeout.
898 set_listen_cb (void *cls,
899 const struct GNUNET_PeerIdentity *other_peer,
900 const struct GNUNET_MessageHeader *context_msg,
901 struct GNUNET_SET_Request *request)
903 struct ConsensusSession *session = cls;
904 struct GNUNET_CONSENSUS_RoundContextMessage *msg = (struct GNUNET_CONSENSUS_RoundContextMessage *) context_msg;
905 struct ConsensusPeerInformation *cpi;
906 struct GNUNET_SET_OperationHandle *set_op;
907 struct RoundInfo round_info;
911 if (NULL == context_msg)
917 index = get_peer_idx (other_peer, session);
925 round_info.round = ntohl (msg->round);
926 round_info.exp_round = ntohl (msg->exp_round);
927 round_info.exp_subround = ntohl (msg->exp_subround);
929 cpi = &session->info[index];
931 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%d got set request from P%d\n", session->local_peer_idx, index);
933 switch (session->current_round)
935 case CONSENSUS_ROUND_BEGIN:
936 /* we're in the begin round, so requests for the exchange round may
937 * come in, they will be delayed for now! */
938 case CONSENSUS_ROUND_EXCHANGE:
939 cmp = rounds_compare (session, &round_info);
942 /* the other peer is too late */
946 /* kill old request, if any. this is legal,
947 * as the other peer would not make a new request if it would want to
948 * complete the old one! */
949 if (NULL != cpi->set_op)
951 GNUNET_SET_operation_cancel (cpi->set_op);
954 set_op = GNUNET_SET_accept (request, GNUNET_SET_RESULT_ADDED,
955 set_result_cb, &session->info[index]);
958 cpi->set_op = set_op;
959 GNUNET_SET_commit (set_op, session->element_set);
960 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%d commited to set request from P%d\n", session->local_peer_idx, index);
964 /* if there's a exp subround running, mark it as finished, as the set op has been canceled! */
965 cpi->delayed_set_op = set_op;
966 cpi->delayed_round_info = round_info;
967 cpi->exp_subround_finished = GNUNET_YES;
968 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%d delaying set request from P%d\n", session->local_peer_idx, index);
972 GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "P%d got unexpected set request in round %d from P%d\n",
973 session->local_peer_idx, session->current_round, index);
981 * Initialize the session, continue receiving messages from the owning client
983 * @param session the session to initialize
984 * @param join_msg the join message from the client
987 initialize_session (struct ConsensusSession *session,
988 struct GNUNET_CONSENSUS_JoinMessage *join_msg)
990 struct ConsensusSession *other_session;
992 initialize_session_peer_list (session, join_msg);
993 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "session with %u peers\n", session->num_peers);
994 compute_global_id (session, &join_msg->session_id);
996 /* check if some local client already owns the session.
997 * it is only legal to have a session with an existing global id
998 * if all other sessions with this global id are finished.*/
999 other_session = sessions_head;
1000 while (NULL != other_session)
1002 if ((other_session != session) &&
1003 (0 == GNUNET_CRYPTO_hash_cmp (&session->global_id, &other_session->global_id)))
1005 if (CONSENSUS_ROUND_FINISH != other_session->current_round)
1008 destroy_session (session);
1013 other_session = other_session->next;
1016 session->local_peer_idx = get_peer_idx (&my_peer, session);
1017 GNUNET_assert (-1 != session->local_peer_idx);
1018 session->element_set = GNUNET_SET_create (cfg, GNUNET_SET_OPERATION_UNION);
1019 GNUNET_assert (NULL != session->element_set);
1020 session->set_listener = GNUNET_SET_listen (cfg, GNUNET_SET_OPERATION_UNION,
1021 &session->global_id,
1022 set_listen_cb, session);
1023 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "%d is the local peer\n", session->local_peer_idx);
1024 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "session %s initialized\n", GNUNET_h2s (&session->global_id));
1028 static struct ConsensusSession *
1029 get_session_by_client (struct GNUNET_SERVER_Client *client)
1031 struct ConsensusSession *session;
1033 session = sessions_head;
1034 while (NULL != session)
1036 if (session->client == client)
1038 session = session->next;
1045 * Called when a client wants to join a consensus session.
1048 * @param client client that sent the message
1049 * @param m message sent by the client
1052 client_join (void *cls,
1053 struct GNUNET_SERVER_Client *client,
1054 const struct GNUNET_MessageHeader *m)
1056 struct ConsensusSession *session;
1058 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "join message sent by client\n");
1060 session = get_session_by_client (client);
1061 if (NULL != session)
1064 GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
1067 session = GNUNET_new (struct ConsensusSession);
1068 session->client = client;
1069 session->client_mq = GNUNET_MQ_queue_for_server_client (client);
1070 GNUNET_CONTAINER_DLL_insert (sessions_head, sessions_tail, session);
1071 initialize_session (session, (struct GNUNET_CONSENSUS_JoinMessage *) m);
1072 GNUNET_SERVER_receive_done (client, GNUNET_OK);
1074 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "join done\n");
1079 * Called when a client performs an insert operation.
1081 * @param cls (unused)
1082 * @param client client handle
1083 * @param m message sent by the client
1086 client_insert (void *cls,
1087 struct GNUNET_SERVER_Client *client,
1088 const struct GNUNET_MessageHeader *m)
1090 struct ConsensusSession *session;
1091 struct GNUNET_CONSENSUS_ElementMessage *msg;
1092 struct GNUNET_SET_Element *element;
1093 ssize_t element_size;
1095 session = get_session_by_client (client);
1097 if (NULL == session)
1100 GNUNET_SERVER_client_disconnect (client);
1104 if (CONSENSUS_ROUND_BEGIN != session->current_round)
1107 GNUNET_SERVER_client_disconnect (client);
1111 msg = (struct GNUNET_CONSENSUS_ElementMessage *) m;
1112 element_size = ntohs (msg->header.size) - sizeof (struct GNUNET_CONSENSUS_ElementMessage);
1113 if (element_size < 0)
1119 element = GNUNET_malloc (sizeof (struct GNUNET_SET_Element) + element_size);
1120 element->type = msg->element_type;
1121 element->size = element_size;
1122 memcpy (&element[1], &msg[1], element_size);
1123 element->data = &element[1];
1124 GNUNET_SET_add_element (session->element_set, element, NULL, NULL);
1125 GNUNET_free (element);
1126 GNUNET_SERVER_receive_done (client, GNUNET_OK);
1128 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "P%u: element added\n", session->local_peer_idx);
1133 * Called when a client performs the conclude operation.
1135 * @param cls (unused)
1136 * @param client client handle
1137 * @param message message sent by the client
1140 client_conclude (void *cls,
1141 struct GNUNET_SERVER_Client *client,
1142 const struct GNUNET_MessageHeader *message)
1144 struct ConsensusSession *session;
1145 struct GNUNET_CONSENSUS_ConcludeMessage *cmsg;
1148 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "conclude requested\n");
1149 cmsg = (struct GNUNET_CONSENSUS_ConcludeMessage *) message;
1150 session = get_session_by_client (client);
1151 if (NULL == session)
1153 /* client not found */
1155 GNUNET_SERVER_client_disconnect (client);
1158 if (CONSENSUS_ROUND_BEGIN != session->current_round)
1160 /* client requested conclude twice */
1164 if (session->num_peers <= 1)
1166 /* FIXME: what to do here? */
1167 //send_client_conclude_done (session);
1171 session->conclude_timeout = GNUNET_TIME_relative_ntoh (cmsg->timeout);
1172 /* the 'begin' round is over, start with the next, actual round */
1173 round_over (session, NULL);
1176 GNUNET_assert (CONSENSUS_ROUND_BEGIN != session->current_round);
1177 GNUNET_SERVER_receive_done (client, GNUNET_OK);
1182 * Called to clean up, after a shutdown has been requested.
1184 * @param cls closure
1185 * @param tc context information (why was this task triggered now)
1188 shutdown_task (void *cls,
1189 const struct GNUNET_SCHEDULER_TaskContext *tc)
1191 while (NULL != sessions_head)
1192 destroy_session (sessions_head);
1194 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "handled shutdown request\n");
1199 * Clean up after a client after it is
1200 * disconnected (either by us or by itself)
1202 * @param cls closure, unused
1203 * @param client the client to clean up after
1206 handle_client_disconnect (void *cls, struct GNUNET_SERVER_Client *client)
1208 struct ConsensusSession *session;
1210 session = get_session_by_client (client);
1211 if (NULL == session)
1213 if ((CONSENSUS_ROUND_BEGIN == session->current_round) ||
1214 (CONSENSUS_ROUND_FINISH == session->current_round))
1215 destroy_session (session);
1217 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "client disconnected, but waiting for consensus to finish\n");
1222 * Start processing consensus requests.
1224 * @param cls closure
1225 * @param server the initialized server
1226 * @param c configuration to use
1229 run (void *cls, struct GNUNET_SERVER_Handle *server,
1230 const struct GNUNET_CONFIGURATION_Handle *c)
1232 static const struct GNUNET_SERVER_MessageHandler server_handlers[] = {
1233 {&client_conclude, NULL, GNUNET_MESSAGE_TYPE_CONSENSUS_CLIENT_CONCLUDE,
1234 sizeof (struct GNUNET_CONSENSUS_ConcludeMessage)},
1235 {&client_insert, NULL, GNUNET_MESSAGE_TYPE_CONSENSUS_CLIENT_INSERT, 0},
1236 {&client_join, NULL, GNUNET_MESSAGE_TYPE_CONSENSUS_CLIENT_JOIN, 0},
1242 if (GNUNET_OK != GNUNET_CRYPTO_get_host_identity (cfg, &my_peer))
1244 GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "could not retrieve host identity\n");
1246 GNUNET_SCHEDULER_shutdown ();
1249 GNUNET_SERVER_add_handlers (server, server_handlers);
1250 GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL, &shutdown_task, NULL);
1251 GNUNET_SERVER_disconnect_notify (server, handle_client_disconnect, NULL);
1252 GNUNET_log (GNUNET_ERROR_TYPE_INFO, "consensus running\n");
1257 * The main function for the consensus service.
1259 * @param argc number of arguments from the command line
1260 * @param argv command line arguments
1261 * @return 0 ok, 1 on error
1264 main (int argc, char *const *argv)
1267 ret = GNUNET_SERVICE_run (argc, argv, "consensus", GNUNET_SERVICE_OPTION_NONE, &run, NULL);
1268 GNUNET_log (GNUNET_ERROR_TYPE_INFO, "exit (%d)\n", GNUNET_OK != ret);
1269 return (GNUNET_OK == ret) ? 0 : 1;