2 This file is part of GNUnet
3 Copyright (C) 2012 GNUnet e.V.
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.
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.
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/>.
18 SPDX-License-Identifier: AGPL3.0-or-later
22 * @author Florian Dold
25 * Multi-peer set reconciliation
27 * @defgroup consensus Consensus service
28 * Multi-peer set reconciliation
32 #ifndef GNUNET_CONSENSUS_SERVICE_H
33 #define GNUNET_CONSENSUS_SERVICE_H
38 #if 0 /* keep Emacsens' auto-indent happy */
43 #include "gnunet_common.h"
44 #include "gnunet_time_lib.h"
45 #include "gnunet_configuration_lib.h"
46 #include "gnunet_set_service.h"
50 * Elements inserted into the consensus set by the client
51 * may not be larger than this constant, since types in
52 * the upper range are used by CONSENSUS internally.
54 #define GNUNET_CONSENSUS_ELEMENT_TYPE_USER_MAX 0xFFF0
58 * Called when a new element was received from another peer, or an error occurred.
59 * May deliver duplicate values.
60 * Elements given to a consensus operation by the local peer are NOT given
64 * @param element new element, NULL on error
66 typedef void (*GNUNET_CONSENSUS_ElementCallback) (void *cls,
67 const struct GNUNET_SET_Element *element);
72 * Opaque handle for the consensus service.
74 struct GNUNET_CONSENSUS_Handle;
78 * Create a consensus session. The set being reconciled is initially
83 * @param peers array of peers participating in this consensus session
84 * Inclusion of the local peer is optional.
85 * @param session_id session identifier
86 * Allows a group of peers to have more than consensus session.
87 * @param start start time of the consensus, conclude should be called before
89 * @param deadline time when the consensus should have concluded
90 * @param new_element_cb callback, called when a new element is added to the set by
91 * another peer. Also called when an error occurs.
92 * @param new_element_cls closure for new_element
93 * @return handle to use, NULL on error
95 struct GNUNET_CONSENSUS_Handle *
96 GNUNET_CONSENSUS_create (const struct GNUNET_CONFIGURATION_Handle *cfg,
97 unsigned int num_peers,
98 const struct GNUNET_PeerIdentity *peers,
99 const struct GNUNET_HashCode *session_id,
100 struct GNUNET_TIME_Absolute start,
101 struct GNUNET_TIME_Absolute deadline,
102 GNUNET_CONSENSUS_ElementCallback new_element_cb,
103 void *new_element_cls);
107 * Called when an insertion (transmission to consensus service, which
108 * does not imply fully consensus on this element with all other
109 * peers) was successful. May not call GNUNET_CONSENSUS_destroy();
110 * schedule a task to call GNUNET_CONSENSUS_destroy() instead (if
114 * @param success #GNUNET_OK on success, #GNUNET_SYSERR if
115 * the insertion and thus the consensus failed for good
117 typedef void (*GNUNET_CONSENSUS_InsertDoneCallback) (void *cls,
122 * Insert an element in the set being reconsiled. Only transmit changes to
123 * other peers if GNUNET_CONSENSUS_begin() has been called.
124 * Must not be called after GNUNET_CONSENSUS_conclude().
125 * May not call GNUNET_CONSENSUS_destroy(); schedule a task to call
126 * GNUNET_CONSENSUS_destroy() instead (if needed).
128 * @param consensus handle for the consensus session
129 * @param element the element to be inserted
130 * @param idc function called when we are done with this element and it
131 * is thus allowed to call GNUNET_CONSENSUS_insert() again
132 * @param idc_cls closure for @a idc
135 GNUNET_CONSENSUS_insert (struct GNUNET_CONSENSUS_Handle *consensus,
136 const struct GNUNET_SET_Element *element,
137 GNUNET_CONSENSUS_InsertDoneCallback idc,
143 * Called when a conclusion was successful.
147 typedef void (*GNUNET_CONSENSUS_ConcludeCallback) (void *cls);
151 * We are finished inserting new elements into the consensus;
152 * try to conclude the consensus within a given time window.
154 * @param consensus consensus session
155 * @param conclude called when the conclusion was successful
156 * @param conclude_cls closure for the conclude callback
159 GNUNET_CONSENSUS_conclude (struct GNUNET_CONSENSUS_Handle *consensus,
160 GNUNET_CONSENSUS_ConcludeCallback conclude,
165 * Destroy a consensus handle (free all state associated with
166 * it, no longer call any of the callbacks).
168 * @param consensus handle to destroy
171 GNUNET_CONSENSUS_destroy (struct GNUNET_CONSENSUS_Handle *consensus);
174 #if 0 /* keep Emacsens' auto-indent happy */
183 /** @} */ /* end of group */