+// 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_hashes::sha256d::Hash as Sha256dHash;
-use bitcoin::network::constants::Network;
-
-use util::logger::Logger;
+use bitcoin::hash_types::Txid;
-use std::sync::{Mutex,Weak,MutexGuard,Arc};
-use std::sync::atomic::{AtomicUsize, Ordering};
use std::collections::HashSet;
-/// Used to give chain error details upstream
-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: &Sha256dHash, 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: (Sha256dHash, u32), out_script: &Script);
-
- /// Indicates that a listener needs to see all transactions.
- fn watch_all_txn(&self);
-
- /// Register the given listener to receive events. Only a weak pointer is provided and the
- /// registration should be freed once that pointer expires.
- fn register_listener(&self, listener: Weak<ChainListener>);
- //TODO: unregister
-
- /// 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: Sha256dHash, unspent_tx_output_identifier: u64) -> Result<(Script, u64), ChainError>;
-}
-
/// An interface to send a transaction to the Bitcoin network.
pub trait BroadcasterInterface: Sync + Send {
/// Sends a transaction out to (hopefully) be mined.
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.
- /// Note that if 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 may 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 {
/// 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.
///
/// This translates to:
/// * satoshis-per-byte * 250
/// * ceil(satoshis-per-kbyte / 4)
- fn get_est_sat_per_1000_weight(&self, confirmation_target: ConfirmationTarget) -> u64;
+ fn get_est_sat_per_1000_weight(&self, confirmation_target: ConfirmationTarget) -> u32;
}
+/// Minimum relay fee as required by bitcoin network mempool policy.
+pub const MIN_RELAY_FEE_SAT_PER_1000_WEIGHT: u64 = 4000;
+
/// Utility for tracking registered txn/outpoints and checking for matches
+#[cfg_attr(test, derive(PartialEq))]
pub struct ChainWatchedUtil {
watch_all: bool,
// We are more conservative in matching during testing to ensure everything matches *exactly*,
// even though during normal runtime we take more optimized match approaches...
#[cfg(test)]
- watched_txn: HashSet<(Sha256dHash, Script)>,
+ watched_txn: HashSet<(Txid, Script)>,
#[cfg(not(test))]
watched_txn: HashSet<Script>,
- watched_outpoints: HashSet<(Sha256dHash, u32)>,
+ watched_outpoints: HashSet<(Txid, u32)>,
}
impl ChainWatchedUtil {
/// Registers a tx for monitoring, returning true if it was a new tx and false if we'd already
/// been watching for it.
- pub fn register_tx(&mut self, txid: &Sha256dHash, script_pub_key: &Script) -> bool {
+ pub fn register_tx(&mut self, txid: &Txid, script_pub_key: &Script) -> bool {
if self.watch_all { return false; }
#[cfg(test)]
{
/// Registers an outpoint for monitoring, returning true if it was a new outpoint and false if
/// we'd already been watching for it
- pub fn register_outpoint(&mut self, outpoint: (Sha256dHash, u32), _script_pub_key: &Script) -> bool {
+ pub fn register_outpoint(&mut self, outpoint: (Txid, u32), _script_pub_key: &Script) -> bool {
if self.watch_all { return false; }
self.watched_outpoints.insert(outpoint)
}
false
}
}
-
-/// 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>,
- listeners: Mutex<Vec<Weak<ChainListener>>>,
- reentered: AtomicUsize,
- logger: Arc<Logger>,
-}
-
-/// Register listener
-impl ChainWatchInterface for ChainWatchInterfaceUtil {
- fn install_watch_tx(&self, txid: &Sha256dHash, 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: (Sha256dHash, 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 register_listener(&self, listener: Weak<ChainListener>) {
- let mut vec = self.listeners.lock().unwrap();
- vec.push(listener);
- }
-
- fn get_chain_utxo(&self, genesis_hash: Sha256dHash, _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)
- }
-}
-
-impl ChainWatchInterfaceUtil {
- /// Creates a new ChainWatchInterfaceUtil for the given network
- pub fn new(network: Network, logger: Arc<Logger>) -> ChainWatchInterfaceUtil {
- ChainWatchInterfaceUtil {
- network: network,
- watched: Mutex::new(ChainWatchedUtil::new()),
- listeners: Mutex::new(Vec::new()),
- reentered: AtomicUsize::new(1),
- logger: logger,
- }
- }
-
- /// 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_with_filtering(&self, block: &Block, height: u32) {
- let mut reentered = true;
- while reentered {
- 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);
- }
- }
- }
- reentered = self.block_connected_checked(&block.header, height, matched.as_slice(), matched_index.as_slice());
- }
- }
-
- /// Notify listeners that a block was disconnected.
- pub fn block_disconnected(&self, header: &BlockHeader, disconnected_height: u32) {
- let listeners = self.listeners.lock().unwrap().clone();
- for listener in listeners.iter() {
- match listener.upgrade() {
- Some(arc) => arc.block_disconnected(&header, disconnected_height),
- None => ()
- }
- }
- }
-
- /// 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.reentered.load(Ordering::Relaxed);
-
- let listeners = self.listeners.lock().unwrap().clone();
- for listener in listeners.iter() {
- match listener.upgrade() {
- Some(arc) => arc.block_connected(header, height, txn_matched, indexes_of_txn_matched),
- None => ()
- }
- }
- return last_seen != self.reentered.load(Ordering::Relaxed);
- }
-
- /// 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)
- }
-}