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

// Copyright 2021 MaidSafe.net limited.
//
// This SAFE Network Software is licensed to you under The General Public License (GPL), version 3.
// Unless required by applicable law or agreed to in writing, the SAFE Network Software distributed
// under the GPL Licence is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. Please review the Licences for the specific language governing
// permissions and limitations relating to use of the SAFE Network Software.

//! Peer implementation for a resilient decentralised network infrastructure.
//!
//! This is the "engine room" of a hybrid p2p network, where the p2p nodes are built on
//! top of this library. The features this library gives us is:
//!
//!  * Sybil resistant p2p nodes
//!  * Sharded network with up to approx 200 p2p nodes per shard
//!  * All data encrypted at network level with TLS 1.3
//!  * Network level `quic` compatibility, satisfying industry standards and further
//!    obfuscating the p2p network data.
//!  * Upgrade capable nodes.
//!  * All network messages signed via ED25519 and/or BLS
//!  * Section consensus via an ABFT algorithm (PARSEC)

// ############################################################################
// Public API
// ############################################################################
pub use self::{
    cache::Cache,
    error::{Error, Result},
    event::{Event, NodeElderChange, SendStream},
    peer::PeerUtils,
    routing_api::{Config, EventStream, Routing},
    section::{
        SectionAuthorityProviderUtils, FIRST_SECTION_MAX_AGE, FIRST_SECTION_MIN_AGE, MIN_ADULT_AGE,
        MIN_AGE,
    },
};
pub use qp2p::Config as TransportConfig;

pub use xor_name::{Prefix, XorName, XOR_NAME_LEN}; // TODO remove pub on API update

// ############################################################################
// Private
// ############################################################################

mod cache;
mod core;
mod dkg;
mod ed25519;
mod error;
mod event;
mod messages;
mod network;
mod node;
mod peer;
mod relocation;
mod routing_api;
mod section;

/// Recommended section size. sn_routing will keep adding nodes until the section reaches this size.
/// More nodes might be added if requested by the upper layers.
/// This number also detemines when split happens - if both post-split sections would have at least
/// this number of nodes.
pub const RECOMMENDED_SECTION_SIZE: usize = 2 * ELDER_SIZE;

/// Number of elders per section.
pub const ELDER_SIZE: usize = 7;

/// SuperMajority of a given group (i.e. > 2/3)
#[inline]
pub(crate) const fn supermajority(group_size: usize) -> usize {
    1 + group_size * 2 / 3
}

#[cfg(test)]
mod tests {
    use super::supermajority;
    use proptest::prelude::*;

    #[test]
    fn supermajority_of_small_group() {
        assert_eq!(supermajority(0), 1);
        assert_eq!(supermajority(1), 1);
        assert_eq!(supermajority(2), 2);
        assert_eq!(supermajority(3), 3);
        assert_eq!(supermajority(4), 3);
        assert_eq!(supermajority(5), 4);
        assert_eq!(supermajority(6), 5);
        assert_eq!(supermajority(7), 5);
        assert_eq!(supermajority(8), 6);
        assert_eq!(supermajority(9), 7);
    }

    proptest! {
        #[test]
        fn proptest_supermajority(a in 0usize..10000) {
            let n = 3 * a;
            assert_eq!(supermajority(n),     2 * a + 1);
            assert_eq!(supermajority(n + 1), 2 * a + 1);
            assert_eq!(supermajority(n + 2), 2 * a + 2);
        }
    }
}