+// This file is Copyright its original authors, visible in version control
+// history.
+//
+// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
+// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, 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 transaction indices within a given block that the ChainWatchInterface is
- /// watching for.
- fn filter_block(&self, block: &Block) -> Vec<usize>;
-
- /// 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 {
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: &[usize]);
- /// 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 {
/// 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.
///
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<C> = Arc<BlockNotifier<'static, Arc<ChainListener>, 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<Target = ChainListener + 'a> + 'a, C: Deref> where C::Target: ChainWatchInterface {
- listeners: Mutex<Vec<CL>>,
- chain_monitor: C,
- phantom: PhantomData<&'a ()>,
-}
-
-impl<'a, CL: Deref<Target = ChainListener + 'a> + '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(&self, block: &Block, height: u32) {
- let mut reentered = true;
- while reentered {
- let matched_indexes = self.chain_monitor.filter_block(block);
- let mut matched_txn = Vec::new();
- for index in matched_indexes.iter() {
- matched_txn.push(&block.txdata[*index]);
- }
- reentered = self.block_connected_checked(&block.header, height, matched_txn.as_slice(), matched_indexes.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: &[usize]) -> 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<ChainWatchedUtil>,
- 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(&self, block: &Block) -> Vec<usize> {
- 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_index.push(index);
- }
- }
- }
- 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<ChainWatchedUtil>) -> 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)));
- }
-}
projects / rust-lightning / blobdiff