1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
// This file is part of Substrate.

// Copyright (C) Parity Technologies (UK) Ltd.
// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.

#![warn(missing_docs)]
#![recursion_limit = "1024"]

//! Substrate authority discovery.
//!
//! This crate enables Substrate authorities to discover and directly connect to
//! other authorities. It is split into two components the [`Worker`] and the
//! [`Service`].
//!
//! See [`Worker`] and [`Service`] for more documentation.

pub use crate::{
	error::Error,
	service::Service,
	worker::{AuthorityDiscovery, NetworkProvider, Role, Worker},
};

use std::{collections::HashSet, sync::Arc, time::Duration};

use futures::{
	channel::{mpsc, oneshot},
	Stream,
};

use sc_network::{event::DhtEvent, Multiaddr};
use sc_network_types::PeerId;
use sp_authority_discovery::AuthorityId;
use sp_blockchain::HeaderBackend;
use sp_runtime::traits::Block as BlockT;

mod error;
mod interval;
mod service;
mod worker;

#[cfg(test)]
mod tests;

/// Configuration of [`Worker`].
pub struct WorkerConfig {
	/// The maximum interval in which the node will publish its own address on the DHT.
	///
	/// By default this is set to 1 hour.
	pub max_publish_interval: Duration,

	/// Interval at which the keystore is queried. If the keys have changed, unconditionally
	/// re-publish its addresses on the DHT.
	///
	/// By default this is set to 1 minute.
	pub keystore_refresh_interval: Duration,

	/// The maximum interval in which the node will query the DHT for new entries.
	///
	/// By default this is set to 10 minutes.
	pub max_query_interval: Duration,

	/// If `false`, the node won't publish on the DHT multiaddresses that contain non-global
	/// IP addresses (such as 10.0.0.1).
	///
	/// Recommended: `false` for live chains, and `true` for local chains or for testing.
	///
	/// Defaults to `true` to avoid the surprise factor.
	pub publish_non_global_ips: bool,

	/// Public addresses set by the node operator to always publish first in the authority
	/// discovery DHT record.
	pub public_addresses: Vec<Multiaddr>,

	/// Reject authority discovery records that are not signed by their network identity (PeerId)
	///
	/// Defaults to `false` to provide compatibility with old versions
	pub strict_record_validation: bool,
}

impl Default for WorkerConfig {
	fn default() -> Self {
		Self {
			// Kademlia's default time-to-live for Dht records is 36h, republishing records every
			// 24h through libp2p-kad. Given that a node could restart at any point in time, one can
			// not depend on the republishing process, thus publishing own external addresses should
			// happen on an interval < 36h.
			max_publish_interval: Duration::from_secs(1 * 60 * 60),
			keystore_refresh_interval: Duration::from_secs(60),
			// External addresses of remote authorities can change at any given point in time. The
			// interval on which to trigger new queries for the current and next authorities is a
			// trade off between efficiency and performance.
			//
			// Querying 700 [`AuthorityId`]s takes ~8m on the Kusama DHT (16th Nov 2020) when
			// comparing `authority_discovery_authority_addresses_requested_total` and
			// `authority_discovery_dht_event_received`.
			max_query_interval: Duration::from_secs(10 * 60),
			publish_non_global_ips: true,
			public_addresses: Vec::new(),
			strict_record_validation: false,
		}
	}
}

/// Create a new authority discovery [`Worker`] and [`Service`].
///
/// See the struct documentation of each for more details.
pub fn new_worker_and_service<Client, Block, DhtEventStream>(
	client: Arc<Client>,
	network: Arc<dyn NetworkProvider>,
	dht_event_rx: DhtEventStream,
	role: Role,
	prometheus_registry: Option<prometheus_endpoint::Registry>,
) -> (Worker<Client, Block, DhtEventStream>, Service)
where
	Block: BlockT + Unpin + 'static,
	Client: AuthorityDiscovery<Block> + Send + Sync + 'static + HeaderBackend<Block>,
	DhtEventStream: Stream<Item = DhtEvent> + Unpin,
{
	new_worker_and_service_with_config(
		Default::default(),
		client,
		network,
		dht_event_rx,
		role,
		prometheus_registry,
	)
}

/// Same as [`new_worker_and_service`] but with support for providing the `config`.
///
/// When in doubt use [`new_worker_and_service`] as it will use the default configuration.
pub fn new_worker_and_service_with_config<Client, Block, DhtEventStream>(
	config: WorkerConfig,
	client: Arc<Client>,
	network: Arc<dyn NetworkProvider>,
	dht_event_rx: DhtEventStream,
	role: Role,
	prometheus_registry: Option<prometheus_endpoint::Registry>,
) -> (Worker<Client, Block, DhtEventStream>, Service)
where
	Block: BlockT + Unpin + 'static,
	Client: AuthorityDiscovery<Block> + 'static,
	DhtEventStream: Stream<Item = DhtEvent> + Unpin,
{
	let (to_worker, from_service) = mpsc::channel(0);

	let worker =
		Worker::new(from_service, client, network, dht_event_rx, role, prometheus_registry, config);
	let service = Service::new(to_worker);

	(worker, service)
}

/// Message send from the [`Service`] to the [`Worker`].
pub(crate) enum ServicetoWorkerMsg {
	/// See [`Service::get_addresses_by_authority_id`].
	GetAddressesByAuthorityId(AuthorityId, oneshot::Sender<Option<HashSet<Multiaddr>>>),
	/// See [`Service::get_authority_ids_by_peer_id`].
	GetAuthorityIdsByPeerId(PeerId, oneshot::Sender<Option<HashSet<AuthorityId>>>),
}