diff --git a/lightning/src/ln/channel_id.rs b/lightning/src/ln/channel_id.rs new file mode 100644 index 00000000000..f37e8ff0ccf --- /dev/null +++ b/lightning/src/ln/channel_id.rs @@ -0,0 +1,143 @@ +// This file is Copyright its original authors, visible in version control +// history. +// +// This file is licensed under the Apache License, Version 2.0 or the MIT license +// , at your option. +// You may not use this file except in accordance with one or both of these +// licenses. + +use crate::ln::msgs::DecodeError; +use crate::sign::EntropySource; +use crate::util::ser::{Readable, Writeable, Writer}; + +use bitcoin::hashes::hex::ToHex; + +use crate::io; +use crate::prelude::*; +use core::fmt; +use core::ops::Deref; + + +/// A unique 32-byte identifier for a channel. +/// Depending on how the ID is generated, several varieties are distinguished (but all are stored as 32 bytes): +/// - v1: generated based on funding tx outpoint (txid&index) +/// - temporary: generated randomly +/// (later planned v2: based on revocation point) +/// The variety (context) is not stored, it is relevant only at creation. +/// This is not exported to bindings users as we just use [u8; 32] directly +#[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)] +pub struct ChannelId { + // The 32-byte data of the ID + data: [u8; 32], +} + +impl ChannelId { + /// Create v1 channel ID based on a funding TX ID and output index + pub fn v1_from_funding_txid(txid: &[u8; 32], output_index: u16) -> Self { + let mut res = [0; 32]; + res[..].copy_from_slice(&txid[..]); + res[30] ^= ((output_index >> 8) & 0xff) as u8; + res[31] ^= ((output_index >> 0) & 0xff) as u8; + Self::from_bytes(res) + } + + /// Create a temporary channel ID randomly, based on an entropy source. + pub fn temporary_from_entropy_source(entropy_source: &ES) -> Self + where ES::Target: EntropySource { + Self::from_bytes(entropy_source.get_secure_random_bytes()) + } + + /// Generic constructor; create a new channel ID from the provided data. + /// Use a more specific *from_* constructor when possible. + /// This constructor is useful for tests, and internally, e.g. when the channel ID is being deserialized. + pub fn from_bytes(data: [u8; 32]) -> Self { + Self{data} + } + + /// Create a channel ID consisting of all-zeros data (placeholder). + pub fn new_zero() -> Self { + Self::from_bytes([0; 32]) + } + + /// Accessor for the channel ID data + pub fn bytes(&self) -> &[u8; 32] { + &self.data + } +} + +impl Writeable for ChannelId { + fn write(&self, w: &mut W) -> Result<(), io::Error> { + self.data.write(w) + } +} + +impl Readable for ChannelId { + fn read(r: &mut R) -> Result { + let buf: [u8; 32] = Readable::read(r)?; + Ok(ChannelId::from_bytes(buf)) + } +} + +impl ToHex for ChannelId { + fn to_hex(&self) -> String { + self.data.to_hex() + } +} + +impl fmt::Display for ChannelId { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + crate::util::logger::DebugBytes(&self.data).fmt(f) + } +} + +#[cfg(test)] +mod tests { + use crate::ln::ChannelId; + use crate::util::ser::{Readable, Writeable}; + use crate::util::test_utils; + use bitcoin::hashes::hex::ToHex; + use crate::prelude::*; + use crate::io; + + #[test] + fn test_channel_id_new_from_data() { + let data: [u8; 32] = [2; 32]; + let channel_id = ChannelId::from_bytes(data.clone()); + assert_eq!(*channel_id.bytes(), data); + } + + #[test] + fn test_channel_id_v1_from_funding_txid() { + let channel_id = ChannelId::v1_from_funding_txid(&[2; 32], 1); + assert_eq!(channel_id.to_hex(), "0202020202020202020202020202020202020202020202020202020202020203"); + } + + #[test] + fn test_channel_id_equals() { + let channel_id11 = ChannelId::v1_from_funding_txid(&[2; 32], 2); + let channel_id12 = ChannelId::v1_from_funding_txid(&[2; 32], 2); + let channel_id21 = ChannelId::v1_from_funding_txid(&[2; 32], 42); + assert_eq!(channel_id11, channel_id12); + assert_ne!(channel_id11, channel_id21); + } + + #[test] + fn test_channel_id_write_read() { + let data: [u8; 32] = [2; 32]; + let channel_id = ChannelId::from_bytes(data.clone()); + + let mut w = test_utils::TestVecWriter(Vec::new()); + channel_id.write(&mut w).unwrap(); + + let channel_id_2 = ChannelId::read(&mut io::Cursor::new(&w.0)).unwrap(); + assert_eq!(channel_id_2, channel_id); + assert_eq!(channel_id_2.bytes(), &data); + } + + #[test] + fn test_channel_id_display() { + let channel_id = ChannelId::from_bytes([42; 32]); + assert_eq!(format!("{}", &channel_id), "2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a"); + } +} diff --git a/lightning/src/ln/mod.rs b/lightning/src/ln/mod.rs index a5de0d4c2f5..bacb9e86c79 100644 --- a/lightning/src/ln/mod.rs +++ b/lightning/src/ln/mod.rs @@ -13,6 +13,7 @@ #[macro_use] pub mod functional_test_utils; +pub mod channel_id; pub mod channelmanager; pub mod inbound_payment; pub mod msgs; @@ -31,6 +32,9 @@ pub mod channel; #[cfg(not(fuzzing))] pub(crate) mod channel; +// Re-export ChannelId +pub use self::channel_id::ChannelId; + pub(crate) mod onion_utils; mod outbound_payment; pub mod wire;