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| 1 | +// This file is Copyright its original authors, visible in version control |
| 2 | +// history. |
| 3 | +// |
| 4 | +// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE |
| 5 | +// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| 6 | +// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option. |
| 7 | +// You may not use this file except in accordance with one or both of these |
| 8 | +// licenses. |
| 9 | + |
| 10 | +use crate::ln::msgs::DecodeError; |
| 11 | +use crate::sign::EntropySource; |
| 12 | +use crate::util::ser::{Readable, Writeable, Writer}; |
| 13 | + |
| 14 | +use bitcoin::hashes::hex::ToHex; |
| 15 | + |
| 16 | +use crate::io; |
| 17 | +use crate::prelude::*; |
| 18 | +use core::fmt; |
| 19 | +use core::ops::Deref; |
| 20 | + |
| 21 | + |
| 22 | +/// A unique 32-byte identifier for a channel. |
| 23 | +/// Depending on how the ID is generated, several varieties are distinguished (but all are stored as 32 bytes): |
| 24 | +/// - v1: generated based on funding tx outpoint (txid&index) |
| 25 | +/// - temporary: generated randomly |
| 26 | +/// (later planned v2: based on revocation point) |
| 27 | +/// The variety (context) is not stored, it is relevant only at creation. |
| 28 | +/// This is not exported to bindings users as we just use [u8; 32] directly |
| 29 | +#[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)] |
| 30 | +pub struct ChannelId { |
| 31 | + // The 32-byte data of the ID |
| 32 | + data: [u8; 32], |
| 33 | +} |
| 34 | + |
| 35 | +impl ChannelId { |
| 36 | + /// Create v1 channel ID based on a funding TX ID and output index |
| 37 | + pub fn v1_from_funding_txid(txid: &[u8; 32], output_index: u16) -> Self { |
| 38 | + let mut res = [0; 32]; |
| 39 | + res[..].copy_from_slice(&txid[..]); |
| 40 | + res[30] ^= ((output_index >> 8) & 0xff) as u8; |
| 41 | + res[31] ^= ((output_index >> 0) & 0xff) as u8; |
| 42 | + Self::from_bytes(res) |
| 43 | + } |
| 44 | + |
| 45 | + /// Create a temporary channel ID randomly, based on an entropy source. |
| 46 | + pub fn temporary_from_entropy_source<ES: Deref>(entropy_source: &ES) -> Self |
| 47 | + where ES::Target: EntropySource { |
| 48 | + Self::from_bytes(entropy_source.get_secure_random_bytes()) |
| 49 | + } |
| 50 | + |
| 51 | + /// Generic constructor; create a new channel ID from the provided data. |
| 52 | + /// Use a more specific *from_* constructor when possible. |
| 53 | + /// This constructor is useful for tests, and internally, e.g. when the channel ID is being deserialized. |
| 54 | + pub fn from_bytes(data: [u8; 32]) -> Self { |
| 55 | + Self{data} |
| 56 | + } |
| 57 | + |
| 58 | + /// Create a channel ID consisting of all-zeros data (placeholder). |
| 59 | + pub fn new_zero() -> Self { |
| 60 | + Self::from_bytes([0; 32]) |
| 61 | + } |
| 62 | + |
| 63 | + /// Accessor for the channel ID data |
| 64 | + pub fn bytes(&self) -> &[u8; 32] { |
| 65 | + &self.data |
| 66 | + } |
| 67 | +} |
| 68 | + |
| 69 | +impl Writeable for ChannelId { |
| 70 | + fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> { |
| 71 | + self.data.write(w) |
| 72 | + } |
| 73 | +} |
| 74 | + |
| 75 | +impl Readable for ChannelId { |
| 76 | + fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> { |
| 77 | + let buf: [u8; 32] = Readable::read(r)?; |
| 78 | + Ok(ChannelId::from_bytes(buf)) |
| 79 | + } |
| 80 | +} |
| 81 | + |
| 82 | +impl ToHex for ChannelId { |
| 83 | + fn to_hex(&self) -> String { |
| 84 | + self.data.to_hex() |
| 85 | + } |
| 86 | +} |
| 87 | + |
| 88 | +impl fmt::Display for ChannelId { |
| 89 | + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { |
| 90 | + crate::util::logger::DebugBytes(&self.data).fmt(f) |
| 91 | + } |
| 92 | +} |
| 93 | + |
| 94 | +#[cfg(test)] |
| 95 | +mod tests { |
| 96 | + use crate::ln::ChannelId; |
| 97 | + use crate::util::ser::{Readable, Writeable}; |
| 98 | + use crate::util::test_utils; |
| 99 | + use bitcoin::hashes::hex::ToHex; |
| 100 | + use crate::prelude::*; |
| 101 | + use crate::io; |
| 102 | + |
| 103 | + #[test] |
| 104 | + fn test_channel_id_new_from_data() { |
| 105 | + let data: [u8; 32] = [2; 32]; |
| 106 | + let channel_id = ChannelId::from_bytes(data.clone()); |
| 107 | + assert_eq!(*channel_id.bytes(), data); |
| 108 | + } |
| 109 | + |
| 110 | + #[test] |
| 111 | + fn test_channel_id_from_funding_tx2() { |
| 112 | + let channel_id = ChannelId::v1_from_funding_txid(&[2; 32], 1); |
| 113 | + assert_eq!(channel_id.to_hex(), "0202020202020202020202020202020202020202020202020202020202020203"); |
| 114 | + } |
| 115 | + |
| 116 | + #[test] |
| 117 | + fn test_channel_id_equals() { |
| 118 | + let channel_id11 = ChannelId::v1_from_funding_txid(&[2; 32], 2); |
| 119 | + let channel_id12 = ChannelId::v1_from_funding_txid(&[2; 32], 2); |
| 120 | + let channel_id21 = ChannelId::v1_from_funding_txid(&[2; 32], 42); |
| 121 | + assert_eq!(channel_id11, channel_id12); |
| 122 | + assert_ne!(channel_id11, channel_id21); |
| 123 | + } |
| 124 | + |
| 125 | + #[test] |
| 126 | + fn test_channel_id_write_read() { |
| 127 | + let data: [u8; 32] = [2; 32]; |
| 128 | + let channel_id = ChannelId::from_bytes(data.clone()); |
| 129 | + |
| 130 | + let mut w = test_utils::TestVecWriter(Vec::new()); |
| 131 | + channel_id.write(&mut w).unwrap(); |
| 132 | + |
| 133 | + let channel_id_2 = ChannelId::read(&mut io::Cursor::new(&w.0)).unwrap(); |
| 134 | + assert_eq!(channel_id_2, channel_id); |
| 135 | + assert_eq!(channel_id_2.bytes(), &data); |
| 136 | + } |
| 137 | + |
| 138 | + #[test] |
| 139 | + fn test_channel_id_display() { |
| 140 | + let channel_id = ChannelId::from_bytes([42; 32]); |
| 141 | + assert_eq!(format!("{}", &channel_id), "2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a"); |
| 142 | + } |
| 143 | +} |
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