X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;ds=sidebyside;f=lightning%2Fsrc%2Fchain%2Fmod.rs;h=1d51f262216d3620fb068908864db0c545f0f734;hb=aa127f55edc4439b03426644d178e402397329e8;hp=ffa5ed968be4d62e391f613a337f464b37d31b27;hpb=06091cee0fd29549e5e24c673bf361ab3a562529;p=rust-lightning diff --git a/lightning/src/chain/mod.rs b/lightning/src/chain/mod.rs index ffa5ed96..1d51f262 100644 --- a/lightning/src/chain/mod.rs +++ b/lightning/src/chain/mod.rs @@ -1,5 +1,125 @@ +// 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. + //! Structs and traits which allow other parts of rust-lightning to interact with the blockchain. +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 { + /// Returns the transaction output of a funding transaction encoded by [`short_channel_id`]. + /// Returns an error if `genesis_hash` is for a different chain or if such a transaction output + /// is unknown. + /// + /// [`short_channel_id`]: https://github.com/lightningnetwork/lightning-rfc/blob/master/07-routing-gossip.md#definition-of-short_channel_id + fn get_utxo(&self, genesis_hash: &BlockHash, short_channel_id: u64) -> Result; +} + +/// 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. +/// +/// 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; +} + +/// 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); +}