X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fchain%2Fchaininterface.rs;h=a63e0bf1069475f4362ae69c17265519fadc8381;hb=e83dcda03ada7af8aafaa04c660022e4b884245f;hp=89c57dc44c06a39ce0067f8572fc6cdba7da2de6;hpb=f91718722af63bd6dfb960340d539c093c0288aa;p=rust-lightning diff --git a/lightning/src/chain/chaininterface.rs b/lightning/src/chain/chaininterface.rs index 89c57dc4..a63e0bf1 100644 --- a/lightning/src/chain/chaininterface.rs +++ b/lightning/src/chain/chaininterface.rs @@ -1,67 +1,23 @@ +// 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. + //! Traits and utility impls which allow other parts of rust-lightning to interact with the //! blockchain. //! //! Includes traits for monitoring and receiving notifications of new blocks and block //! disconnections, transaction broadcasting, and feerate information requests. -use bitcoin::blockdata::block::{Block, BlockHeader}; use bitcoin::blockdata::transaction::Transaction; use bitcoin::blockdata::script::Script; -use bitcoin::blockdata::constants::genesis_block; -use bitcoin::util::hash::BitcoinHash; -use bitcoin::network::constants::Network; -use bitcoin::hash_types::{Txid, BlockHash}; +use bitcoin::hash_types::Txid; -use std::sync::{Mutex, MutexGuard, Arc}; -use std::sync::atomic::{AtomicUsize, Ordering}; use std::collections::HashSet; -use std::ops::Deref; -use std::marker::PhantomData; -use std::ptr; - -/// Used to give chain error details upstream -#[derive(Clone)] -pub enum ChainError { - /// Client doesn't support UTXO lookup (but the chain hash matches our genesis block hash) - NotSupported, - /// Chain isn't the one watched - NotWatched, - /// Tx doesn't exist or is unconfirmed - UnknownTx, -} - -/// An interface to request notification of certain scripts as they appear the -/// chain. -/// -/// Note that all of the functions implemented here *must* be reentrant-safe (obviously - they're -/// called from inside the library in response to ChainListener events, P2P events, or timer -/// events). -pub trait ChainWatchInterface: Sync + Send { - /// Provides a txid/random-scriptPubKey-in-the-tx which much be watched for. - fn install_watch_tx(&self, txid: &Txid, script_pub_key: &Script); - - /// Provides an outpoint which must be watched for, providing any transactions which spend the - /// given outpoint. - fn install_watch_outpoint(&self, outpoint: (Txid, u32), out_script: &Script); - - /// Indicates that a listener needs to see all transactions. - fn watch_all_txn(&self); - - /// Gets the script and value in satoshis for a given unspent transaction output given a - /// short_channel_id (aka unspent_tx_output_identier). For BTC/tBTC channels the top three - /// bytes are the block height, the next 3 the transaction index within the block, and the - /// final two the output within the transaction. - fn get_chain_utxo(&self, genesis_hash: BlockHash, unspent_tx_output_identifier: u64) -> Result<(Script, u64), ChainError>; - - /// Gets the list of transactions and transaction indices that the ChainWatchInterface is - /// watching for. - fn filter_block<'a>(&self, block: &'a Block) -> (Vec<&'a Transaction>, Vec); - - /// Returns a usize that changes when the ChainWatchInterface's watched data is modified. - /// Users of `filter_block` should pre-save a copy of `reentered`'s return value and use it to - /// determine whether they need to re-filter a given block. - fn reentered(&self) -> usize; -} /// An interface to send a transaction to the Bitcoin network. pub trait BroadcasterInterface: Sync + Send { @@ -69,30 +25,6 @@ pub trait BroadcasterInterface: Sync + Send { fn broadcast_transaction(&self, tx: &Transaction); } -/// A trait indicating a desire to listen for events from the chain -pub trait ChainListener: Sync + Send { - /// Notifies a listener that a block was connected. - /// - /// The txn_matched array should be set to references to transactions which matched the - /// relevant installed watch outpoints/txn, or the full set of transactions in the block. - /// - /// Note that if txn_matched includes only matched transactions, and a new - /// transaction/outpoint is watched during a block_connected call, the block *must* be - /// re-scanned with the new transaction/outpoints and block_connected should be called - /// again with the same header and (at least) the new transactions. - /// - /// Note that if non-new transaction/outpoints are be registered during a call, a second call - /// *must not* happen. - /// - /// This also means those counting confirmations using block_connected callbacks should watch - /// for duplicate headers and not count them towards confirmations! - fn block_connected(&self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], indexes_of_txn_matched: &[u32]); - /// Notifies a listener that a block was disconnected. - /// Unlike block_connected, this *must* never be called twice for the same disconnect event. - /// Height must be the one of the block which was disconnected (not new height of the best chain) - fn block_disconnected(&self, header: &BlockHeader, disconnected_height: u32); -} - /// An enum that represents the speed at which we want a transaction to confirm used for feerate /// estimation. pub enum ConfirmationTarget { @@ -108,8 +40,7 @@ pub enum ConfirmationTarget { /// horizons. /// /// Note that all of the functions implemented here *must* be reentrant-safe (obviously - they're -/// called from inside the library in response to ChainListener events, P2P events, or timer -/// events). +/// called from inside the library in response to chain events, P2P events, or timer events). pub trait FeeEstimator: Sync + Send { /// Gets estimated satoshis of fee required per 1000 Weight-Units. /// @@ -212,265 +143,3 @@ impl ChainWatchedUtil { false } } - -/// BlockNotifierArc is useful when you need a BlockNotifier that points to ChainListeners with -/// static lifetimes, e.g. when you're using lightning-net-tokio (since tokio::spawn requires -/// parameters with static lifetimes). Other times you can afford a reference, which is more -/// efficient, in which case BlockNotifierRef is a more appropriate type. Defining these type -/// aliases prevents issues such as overly long function definitions. -pub type BlockNotifierArc = Arc, C>>; - -/// BlockNotifierRef is useful when you want a BlockNotifier that points to ChainListeners -/// with nonstatic lifetimes. This is useful for when static lifetimes are not needed. Nonstatic -/// lifetimes are more efficient but less flexible, and should be used by default unless static -/// lifetimes are required, e.g. when you're using lightning-net-tokio (since tokio::spawn -/// requires parameters with static lifetimes), in which case BlockNotifierArc is a more -/// appropriate type. Defining these type aliases for common usages prevents issues such as -/// overly long function definitions. -pub type BlockNotifierRef<'a, C> = BlockNotifier<'a, &'a ChainListener, C>; - -/// Utility for notifying listeners about new blocks, and handling block rescans if new watch -/// data is registered. -/// -/// Rather than using a plain BlockNotifier, it is preferable to use either a BlockNotifierArc -/// or a BlockNotifierRef for conciseness. See their documentation for more details, but essentially -/// you should default to using a BlockNotifierRef, and use a BlockNotifierArc instead when you -/// require ChainListeners with static lifetimes, such as when you're using lightning-net-tokio. -pub struct BlockNotifier<'a, CL: Deref + 'a, C: Deref> where C::Target: ChainWatchInterface { - listeners: Mutex>, - chain_monitor: C, - phantom: PhantomData<&'a ()>, -} - -impl<'a, CL: Deref + 'a, C: Deref> BlockNotifier<'a, CL, C> where C::Target: ChainWatchInterface { - /// Constructs a new BlockNotifier without any listeners. - pub fn new(chain_monitor: C) -> BlockNotifier<'a, CL, C> { - BlockNotifier { - listeners: Mutex::new(Vec::new()), - chain_monitor, - phantom: PhantomData, - } - } - - /// Register the given listener to receive events. - pub fn register_listener(&self, listener: CL) { - let mut vec = self.listeners.lock().unwrap(); - vec.push(listener); - } - /// Unregister the given listener to no longer - /// receive events. - /// - /// If the same listener is registered multiple times, unregistering - /// will remove ALL occurrences of that listener. Comparison is done using - /// the pointer returned by the Deref trait implementation. - pub fn unregister_listener(&self, listener: CL) { - let mut vec = self.listeners.lock().unwrap(); - // item is a ref to an abstract thing that dereferences to a ChainListener, - // so dereference it twice to get the ChainListener itself - vec.retain(|item | !ptr::eq(&(**item), &(*listener))); - } - - /// Notify listeners that a block was connected given a full, unfiltered block. - /// - /// Handles re-scanning the block and calling block_connected again if listeners register new - /// watch data during the callbacks for you (see ChainListener::block_connected for more info). - pub fn block_connected<'b>(&self, block: &'b Block, height: u32) { - let mut reentered = true; - while reentered { - let (matched, matched_index) = self.chain_monitor.filter_block(block); - reentered = self.block_connected_checked(&block.header, height, matched.as_slice(), matched_index.as_slice()); - } - } - - /// Notify listeners that a block was connected, given pre-filtered list of transactions in the - /// block which matched the filter (probably using does_match_tx). - /// - /// Returns true if notified listeners registered additional watch data (implying that the - /// block must be re-scanned and this function called again prior to further block_connected - /// calls, see ChainListener::block_connected for more info). - pub fn block_connected_checked(&self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], indexes_of_txn_matched: &[u32]) -> bool { - let last_seen = self.chain_monitor.reentered(); - - let listeners = self.listeners.lock().unwrap(); - for listener in listeners.iter() { - listener.block_connected(header, height, txn_matched, indexes_of_txn_matched); - } - return last_seen != self.chain_monitor.reentered(); - } - - /// Notify listeners that a block was disconnected. - pub fn block_disconnected(&self, header: &BlockHeader, disconnected_height: u32) { - let listeners = self.listeners.lock().unwrap(); - for listener in listeners.iter() { - listener.block_disconnected(&header, disconnected_height); - } - } -} - -/// Utility to capture some common parts of ChainWatchInterface implementors. -/// -/// Keeping a local copy of this in a ChainWatchInterface implementor is likely useful. -pub struct ChainWatchInterfaceUtil { - network: Network, - watched: Mutex, - reentered: AtomicUsize, -} - -// We only expose PartialEq in test since its somewhat unclear exactly what it should do and we're -// only comparing a subset of fields (essentially just checking that the set of things we're -// watching is the same). -#[cfg(test)] -impl PartialEq for ChainWatchInterfaceUtil { - fn eq(&self, o: &Self) -> bool { - self.network == o.network && - *self.watched.lock().unwrap() == *o.watched.lock().unwrap() - } -} - -/// Register listener -impl ChainWatchInterface for ChainWatchInterfaceUtil { - fn install_watch_tx(&self, txid: &Txid, script_pub_key: &Script) { - let mut watched = self.watched.lock().unwrap(); - if watched.register_tx(txid, script_pub_key) { - self.reentered.fetch_add(1, Ordering::Relaxed); - } - } - - fn install_watch_outpoint(&self, outpoint: (Txid, u32), out_script: &Script) { - let mut watched = self.watched.lock().unwrap(); - if watched.register_outpoint(outpoint, out_script) { - self.reentered.fetch_add(1, Ordering::Relaxed); - } - } - - fn watch_all_txn(&self) { - let mut watched = self.watched.lock().unwrap(); - if watched.watch_all() { - self.reentered.fetch_add(1, Ordering::Relaxed); - } - } - - fn get_chain_utxo(&self, genesis_hash: BlockHash, _unspent_tx_output_identifier: u64) -> Result<(Script, u64), ChainError> { - if genesis_hash != genesis_block(self.network).header.bitcoin_hash() { - return Err(ChainError::NotWatched); - } - Err(ChainError::NotSupported) - } - - fn filter_block<'a>(&self, block: &'a Block) -> (Vec<&'a Transaction>, Vec) { - let mut matched = Vec::new(); - let mut matched_index = Vec::new(); - { - let watched = self.watched.lock().unwrap(); - for (index, transaction) in block.txdata.iter().enumerate() { - if self.does_match_tx_unguarded(transaction, &watched) { - matched.push(transaction); - matched_index.push(index as u32); - } - } - } - (matched, matched_index) - } - - fn reentered(&self) -> usize { - self.reentered.load(Ordering::Relaxed) - } -} - -impl ChainWatchInterfaceUtil { - /// Creates a new ChainWatchInterfaceUtil for the given network - pub fn new(network: Network) -> ChainWatchInterfaceUtil { - ChainWatchInterfaceUtil { - network, - watched: Mutex::new(ChainWatchedUtil::new()), - reentered: AtomicUsize::new(1), - } - } - - /// Checks if a given transaction matches the current filter. - pub fn does_match_tx(&self, tx: &Transaction) -> bool { - let watched = self.watched.lock().unwrap(); - self.does_match_tx_unguarded (tx, &watched) - } - - fn does_match_tx_unguarded(&self, tx: &Transaction, watched: &MutexGuard) -> bool { - watched.does_match_tx(tx) - } -} - -#[cfg(test)] -mod tests { - use ln::functional_test_utils::{create_chanmon_cfgs, create_node_cfgs}; - use super::{BlockNotifier, ChainListener}; - use std::ptr; - - #[test] - fn register_listener_test() { - let chanmon_cfgs = create_chanmon_cfgs(1); - let node_cfgs = create_node_cfgs(1, &chanmon_cfgs); - let block_notifier = BlockNotifier::new(node_cfgs[0].chain_monitor); - assert_eq!(block_notifier.listeners.lock().unwrap().len(), 0); - let listener = &node_cfgs[0].chan_monitor.simple_monitor as &ChainListener; - block_notifier.register_listener(listener); - let vec = block_notifier.listeners.lock().unwrap(); - assert_eq!(vec.len(), 1); - let item = vec.first().clone().unwrap(); - assert!(ptr::eq(&(**item), &(*listener))); - } - - #[test] - fn unregister_single_listener_test() { - let chanmon_cfgs = create_chanmon_cfgs(2); - let node_cfgs = create_node_cfgs(2, &chanmon_cfgs); - let block_notifier = BlockNotifier::new(node_cfgs[0].chain_monitor); - let listener1 = &node_cfgs[0].chan_monitor.simple_monitor as &ChainListener; - let listener2 = &node_cfgs[1].chan_monitor.simple_monitor as &ChainListener; - block_notifier.register_listener(listener1); - block_notifier.register_listener(listener2); - let vec = block_notifier.listeners.lock().unwrap(); - assert_eq!(vec.len(), 2); - drop(vec); - block_notifier.unregister_listener(listener1); - let vec = block_notifier.listeners.lock().unwrap(); - assert_eq!(vec.len(), 1); - let item = vec.first().clone().unwrap(); - assert!(ptr::eq(&(**item), &(*listener2))); - } - - #[test] - fn unregister_single_listener_ref_test() { - let chanmon_cfgs = create_chanmon_cfgs(2); - let node_cfgs = create_node_cfgs(2, &chanmon_cfgs); - let block_notifier = BlockNotifier::new(node_cfgs[0].chain_monitor); - block_notifier.register_listener(&node_cfgs[0].chan_monitor.simple_monitor as &ChainListener); - block_notifier.register_listener(&node_cfgs[1].chan_monitor.simple_monitor as &ChainListener); - let vec = block_notifier.listeners.lock().unwrap(); - assert_eq!(vec.len(), 2); - drop(vec); - block_notifier.unregister_listener(&node_cfgs[0].chan_monitor.simple_monitor); - let vec = block_notifier.listeners.lock().unwrap(); - assert_eq!(vec.len(), 1); - let item = vec.first().clone().unwrap(); - assert!(ptr::eq(&(**item), &(*&node_cfgs[1].chan_monitor.simple_monitor))); - } - - #[test] - fn unregister_multiple_of_the_same_listeners_test() { - let chanmon_cfgs = create_chanmon_cfgs(2); - let node_cfgs = create_node_cfgs(2, &chanmon_cfgs); - let block_notifier = BlockNotifier::new(node_cfgs[0].chain_monitor); - let listener1 = &node_cfgs[0].chan_monitor.simple_monitor as &ChainListener; - let listener2 = &node_cfgs[1].chan_monitor.simple_monitor as &ChainListener; - block_notifier.register_listener(listener1); - block_notifier.register_listener(listener1); - block_notifier.register_listener(listener2); - let vec = block_notifier.listeners.lock().unwrap(); - assert_eq!(vec.len(), 3); - drop(vec); - block_notifier.unregister_listener(listener1); - let vec = block_notifier.listeners.lock().unwrap(); - assert_eq!(vec.len(), 1); - let item = vec.first().clone().unwrap(); - assert!(ptr::eq(&(**item), &(*listener2))); - } -}