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/*
* Copyright (c) 2014, 2016 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef RAFT_H
#define RAFT_H 1
#include <stddef.h>
/* Implementation of the Raft consensus algorithm.
*
*
* References
* ==========
*
* Based on Diego Ongaro's Ph.D. thesis, "Consensus: Bridging Theory and
* Practice", available at https://ramcloud.stanford.edu/~ongaro/thesis.pdf.
* References to sections, pages, and figures are from this thesis. Quotations
* in comments also come from this work, in accordance with its license notice,
* reproduced below:
*
* Copyright 2014 by Diego Andres Ongaro. All Rights Reserved.
*
* This work is licensed under a Creative Commons Attribution-3.0 United
* States License. http://creativecommons.org/licenses/by/3.0/us/
*
*
*/
#include <stdbool.h>
#include <stdint.h>
#include "compiler.h"
struct raft;
struct uuid;
/* Default TCP port number for OVSDB RAFT. */
#define RAFT_PORT 6641
struct ovsdb_error *raft_create(const char *file_name,
const char *local_address,
const char *data)
OVS_WARN_UNUSED_RESULT;
struct ovsdb_error *raft_open(const char *file_name, struct raft **);
/* Adds a new server, the one one which this function is called, to an existing
* Raft cluster.
*
* Creates the local copy of the cluster's log in 'file_name'. If 'file_name'
* already exists, then it must be from a previous call to this function for
* the same cluster and the same 'local_address'; if so, then the previous
* attempt to join the cluster will resume.
*
* The new server is located at 'local_address', which must take one of the
* forms "tcp:IP[:PORT]" or "ssl:IP[:PORT]", where IP is an IPv4 address or a
* square bracket enclosed IPv6 address. PORT, if present, is a port number
* that defaults to RAFT_PORT.
*
* Joining the cluster requiring contacting it. Thus, the 'n_remotes'
* addresses in 'remote_addresses' specify the addresses of existing servers in
* the cluster. One server out of the existing cluster is sufficient, as long
* as that server is reachable and not partitioned from the current cluster
* leader. If multiple servers from the cluster are specified, then it is
* sufficient for any of them to meet this criterion.
*
* 'cid' is optional. If specified, the new server will join only the cluster
* with the given cluster ID.
*
* This function blocks until the join succeeds or fails.
*/
int raft_join(const char *file_name, const char *local_address,
const char *remote_addresses[], size_t n_remotes,
const struct uuid *cid, struct raft **);
void raft_close(struct raft *);
void raft_run(struct raft *);
void raft_wait(struct raft *);
uint64_t raft_add_log_entry(struct raft *, const void *data);
#endif /* lib/raft.h */
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