X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fchain%2Fmod.rs;h=c1fceec8c47171969397558db0ce62d11faf93ed;hb=da79fb05fa13f0a7db1bb7ef03f1a4ce9e3b8b35;hp=d0b5b65014d736d27b04c08ca23408da68a8393e;hpb=3ee6a27bc6cef28ba52059a405913ca5c6e1dcb7;p=rust-lightning diff --git a/lightning/src/chain/mod.rs b/lightning/src/chain/mod.rs index d0b5b650..c1fceec8 100644 --- a/lightning/src/chain/mod.rs +++ b/lightning/src/chain/mod.rs @@ -9,16 +9,33 @@ //! Structs and traits which allow other parts of rust-lightning to interact with the blockchain. +use bitcoin::blockdata::block::{Block, BlockHeader}; use bitcoin::blockdata::script::Script; use bitcoin::blockdata::transaction::TxOut; use bitcoin::hash_types::{BlockHash, Txid}; +use chain::channelmonitor::{ChannelMonitor, ChannelMonitorUpdate, ChannelMonitorUpdateErr, MonitorEvent}; +use chain::keysinterface::Sign; use chain::transaction::OutPoint; pub mod chaininterface; +pub mod chainmonitor; +pub mod channelmonitor; pub mod transaction; pub mod keysinterface; +/// An error when accessing the chain via [`Access`]. +/// +/// [`Access`]: trait.Access.html +#[derive(Clone)] +pub enum AccessError { + /// The requested chain is unknown. + UnknownChain, + + /// The requested transaction doesn't exist or hasn't confirmed. + UnknownTx, +} + /// The `Access` trait defines behavior for accessing chain data and state, such as blocks and /// UTXOs. pub trait Access: Send + Sync { @@ -30,44 +47,118 @@ pub trait Access: Send + Sync { fn get_utxo(&self, genesis_hash: &BlockHash, short_channel_id: u64) -> Result; } -/// An error when accessing the chain via [`Access`]. +/// The `Listen` trait is used to be notified of when blocks have been connected or disconnected +/// from the chain. /// -/// [`Access`]: trait.Access.html -#[derive(Clone)] -pub enum AccessError { - /// The requested chain is unknown. - UnknownChain, +/// Useful when needing to replay chain data upon startup or as new chain events occur. +pub trait Listen { + /// Notifies the listener that a block was added at the given height. + fn block_connected(&self, block: &Block, height: u32); - /// The requested transaction doesn't exist or hasn't confirmed. - UnknownTx, + /// Notifies the listener that a block was removed at the given height. + fn block_disconnected(&self, header: &BlockHeader, height: u32); } -/// An interface for providing [`WatchEvent`]s. +/// The `Watch` trait defines behavior for watching on-chain activity pertaining to channels as +/// blocks are connected and disconnected. +/// +/// Each channel is associated with a [`ChannelMonitor`]. Implementations of this trait are +/// responsible for maintaining a set of monitors such that they can be updated accordingly as +/// channel state changes and HTLCs are resolved. See method documentation for specific +/// requirements. +/// +/// Implementations **must** ensure that updates are successfully applied and persisted upon method +/// completion. If an update fails with a [`PermanentFailure`], then it must immediately shut down +/// without taking any further action such as persisting the current state. /// -/// [`WatchEvent`]: enum.WatchEvent.html -pub trait WatchEventProvider { - /// Releases events produced since the last call. Subsequent calls must only return new events. - fn release_pending_watch_events(&self) -> Vec; +/// If an implementation maintains multiple instances of a channel's monitor (e.g., by storing +/// backup copies), then it must ensure that updates are applied across all instances. Otherwise, it +/// could result in a revoked transaction being broadcast, allowing the counterparty to claim all +/// funds in the channel. See [`ChannelMonitorUpdateErr`] for more details about how to handle +/// multiple instances. +/// +/// [`ChannelMonitor`]: channelmonitor/struct.ChannelMonitor.html +/// [`ChannelMonitorUpdateErr`]: channelmonitor/enum.ChannelMonitorUpdateErr.html +/// [`PermanentFailure`]: channelmonitor/enum.ChannelMonitorUpdateErr.html#variant.PermanentFailure +pub trait Watch: Send + Sync { + /// Watches a channel identified by `funding_txo` using `monitor`. + /// + /// Implementations are responsible for watching the chain for the funding transaction along + /// with any spends of outputs returned by [`get_outputs_to_watch`]. In practice, this means + /// calling [`block_connected`] and [`block_disconnected`] on the monitor. + /// + /// [`get_outputs_to_watch`]: channelmonitor/struct.ChannelMonitor.html#method.get_outputs_to_watch + /// [`block_connected`]: channelmonitor/struct.ChannelMonitor.html#method.block_connected + /// [`block_disconnected`]: channelmonitor/struct.ChannelMonitor.html#method.block_disconnected + fn watch_channel(&self, funding_txo: OutPoint, monitor: ChannelMonitor) -> Result<(), ChannelMonitorUpdateErr>; + + /// Updates a channel identified by `funding_txo` by applying `update` to its monitor. + /// + /// Implementations must call [`update_monitor`] with the given update. See + /// [`ChannelMonitorUpdateErr`] for invariants around returning an error. + /// + /// [`update_monitor`]: channelmonitor/struct.ChannelMonitor.html#method.update_monitor + /// [`ChannelMonitorUpdateErr`]: channelmonitor/enum.ChannelMonitorUpdateErr.html + fn update_channel(&self, funding_txo: OutPoint, update: ChannelMonitorUpdate) -> Result<(), ChannelMonitorUpdateErr>; + + /// Returns any monitor events since the last call. Subsequent calls must only return new + /// events. + fn release_pending_monitor_events(&self) -> Vec; } -/// An event indicating on-chain activity to watch for pertaining to a channel. -pub enum WatchEvent { - /// Watch for a transaction with `txid` and having an output with `script_pubkey` as a spending - /// condition. - WatchTransaction { - /// Identifier of the transaction. - txid: Txid, - - /// Spending condition for an output of the transaction. - script_pubkey: Script, - }, - /// Watch for spends of a transaction output identified by `outpoint` having `script_pubkey` as - /// the spending condition. - WatchOutput { - /// Identifier for the output. - outpoint: OutPoint, - - /// Spending condition for the output. - script_pubkey: Script, +/// The `Filter` trait defines behavior for indicating chain activity of interest pertaining to +/// channels. +/// +/// This is useful in order to have a [`Watch`] implementation convey to a chain source which +/// transactions to be notified of. Notification may take the form of pre-filtering blocks or, in +/// the case of [BIP 157]/[BIP 158], only fetching a block if the compact filter matches. If +/// receiving full blocks from a chain source, any further filtering is unnecessary. +/// +/// After an output has been registered, subsequent block retrievals from the chain source must not +/// exclude any transactions matching the new criteria nor any in-block descendants of such +/// transactions. +/// +/// Note that use as part of a [`Watch`] implementation involves reentrancy. Therefore, the `Filter` +/// should not block on I/O. Implementations should instead queue the newly monitored data to be +/// processed later. Then, in order to block until the data has been processed, any `Watch` +/// invocation that has called the `Filter` must return [`TemporaryFailure`]. +/// +/// [`Watch`]: trait.Watch.html +/// [`TemporaryFailure`]: channelmonitor/enum.ChannelMonitorUpdateErr.html#variant.TemporaryFailure +/// [BIP 157]: https://github.com/bitcoin/bips/blob/master/bip-0157.mediawiki +/// [BIP 158]: https://github.com/bitcoin/bips/blob/master/bip-0158.mediawiki +pub trait Filter: Send + Sync { + /// Registers interest in a transaction with `txid` and having an output with `script_pubkey` as + /// a spending condition. + fn register_tx(&self, txid: &Txid, script_pubkey: &Script); + + /// Registers interest in spends of a transaction output identified by `outpoint` having + /// `script_pubkey` as the spending condition. + fn register_output(&self, outpoint: &OutPoint, script_pubkey: &Script); +} + +impl Listen for std::ops::Deref { + fn block_connected(&self, block: &Block, height: u32) { + (**self).block_connected(block, height); + } + + fn block_disconnected(&self, header: &BlockHeader, height: u32) { + (**self).block_disconnected(header, height); + } +} + +impl Listen for (T, U) +where + T::Target: Listen, + U::Target: Listen, +{ + fn block_connected(&self, block: &Block, height: u32) { + self.0.block_connected(block, height); + self.1.block_connected(block, height); + } + + fn block_disconnected(&self, header: &BlockHeader, height: u32) { + self.0.block_disconnected(header, height); + self.1.block_disconnected(header, height); } }