+//! The logic to monitor for on-chain transactions and create the relevant claim responses lives
+//! here.
+//! ChannelMonitor objects are generated by ChannelManager in response to relevant
+//! messages/actions, and MUST be persisted to disk (and, preferably, remotely) before progress can
+//! be made in responding to certain messages, see ManyChannelMonitor for more.
+//! Note that ChannelMonitors are an important part of the lightning trust model and a copy of the
+//! latest ChannelMonitor must always be actively monitoring for chain updates (and no out-of-date
+//! ChannelMonitors should do so). Thus, if you're building rust-lightning into an HSM or other
+//! security-domain-separated system design, you should consider having multiple paths for
+//! ChannelMonitors to get out of the HSM and onto monitoring devices.
+
use bitcoin::blockdata::block::BlockHeader;
use bitcoin::blockdata::transaction::{TxIn,TxOut,SigHashType,Transaction};
use bitcoin::blockdata::transaction::OutPoint as BitcoinOutPoint;
use std::sync::{Arc,Mutex};
use std::{hash,cmp};
+/// An error enum representing a failure to persist a channel monitor update.
pub enum ChannelMonitorUpdateErr {
/// Used to indicate a temporary failure (eg connection to a watchtower failed, but is expected
/// to succeed at some point in the future).
/// If you're using this for local monitoring of your own channels, you probably want to use
/// `OutPoint` as the key, which will give you a ManyChannelMonitor implementation.
pub struct SimpleManyChannelMonitor<Key> {
+ #[cfg(test)] // Used in ChannelManager tests to manipulate channels directly
+ pub monitors: Mutex<HashMap<Key, ChannelMonitor>>,
+ #[cfg(not(test))]
monitors: Mutex<HashMap<Key, ChannelMonitor>>,
chain_monitor: Arc<ChainWatchInterface>,
broadcaster: Arc<BroadcasterInterface>
}
impl<Key : Send + cmp::Eq + hash::Hash + 'static> SimpleManyChannelMonitor<Key> {
+ /// Creates a new object which can be used to monitor several channels given the chain
+ /// interface with which to register to receive notifications.
pub fn new(chain_monitor: Arc<ChainWatchInterface>, broadcaster: Arc<BroadcasterInterface>) -> Arc<SimpleManyChannelMonitor<Key>> {
let res = Arc::new(SimpleManyChannelMonitor {
monitors: Mutex::new(HashMap::new()),
res
}
+ /// Adds or udpates the monitor which monitors the channel referred to by the given key.
pub fn add_update_monitor_by_key(&self, key: Key, monitor: ChannelMonitor) -> Result<(), HandleError> {
let mut monitors = self.monitors.lock().unwrap();
match monitors.get_mut(&key) {
const SERIALIZATION_VERSION: u8 = 1;
const MIN_SERIALIZATION_VERSION: u8 = 1;
+/// A ChannelMonitor handles chain events (blocks connected and disconnected) and generates
+/// on-chain transactions to ensure no loss of funds occurs.
+/// You MUST ensure that no ChannelMonitors for a given channel anywhere contain out-of-date
+/// information and are actively monitoring the chain.
pub struct ChannelMonitor {
funding_txo: Option<(OutPoint, Script)>,
commitment_transaction_number_obscure_factor: u64,
key_storage: KeyStorage,
delayed_payment_base_key: PublicKey,
their_htlc_base_key: Option<PublicKey>,
+ their_delayed_payment_base_key: Option<PublicKey>,
// first is the idx of the first of the two revocation points
their_cur_revocation_points: Option<(u64, PublicKey, Option<PublicKey>)>,
key_storage: self.key_storage.clone(),
delayed_payment_base_key: self.delayed_payment_base_key.clone(),
their_htlc_base_key: self.their_htlc_base_key.clone(),
+ their_delayed_payment_base_key: self.their_delayed_payment_base_key.clone(),
their_cur_revocation_points: self.their_cur_revocation_points.clone(),
our_to_self_delay: self.our_to_self_delay,
self.key_storage != other.key_storage ||
self.delayed_payment_base_key != other.delayed_payment_base_key ||
self.their_htlc_base_key != other.their_htlc_base_key ||
+ self.their_delayed_payment_base_key != other.their_delayed_payment_base_key ||
self.their_cur_revocation_points != other.their_cur_revocation_points ||
self.our_to_self_delay != other.our_to_self_delay ||
self.their_to_self_delay != other.their_to_self_delay ||
}
impl ChannelMonitor {
- pub fn new(revocation_base_key: &SecretKey, delayed_payment_base_key: &PublicKey, htlc_base_key: &SecretKey, our_to_self_delay: u16, destination_script: Script) -> ChannelMonitor {
+ pub(super) fn new(revocation_base_key: &SecretKey, delayed_payment_base_key: &PublicKey, htlc_base_key: &SecretKey, our_to_self_delay: u16, destination_script: Script) -> ChannelMonitor {
ChannelMonitor {
funding_txo: None,
commitment_transaction_number_obscure_factor: 0,
},
delayed_payment_base_key: delayed_payment_base_key.clone(),
their_htlc_base_key: None,
+ their_delayed_payment_base_key: None,
their_cur_revocation_points: None,
our_to_self_delay: our_to_self_delay,
self.payment_preimages.insert(payment_hash.clone(), payment_preimage.clone());
}
+ /// Combines this ChannelMonitor with the information contained in the other ChannelMonitor.
+ /// After a successful call this ChannelMonitor is up-to-date and is safe to use to monitor the
+ /// chain for new blocks/transactions.
pub fn insert_combine(&mut self, mut other: ChannelMonitor) -> Result<(), HandleError> {
if self.funding_txo.is_some() {
// We should be able to compare the entire funding_txo, but in fuzztarget its trivially
self.funding_txo = Some(funding_info);
}
- pub(super) fn set_their_htlc_base_key(&mut self, their_htlc_base_key: &PublicKey) {
+ /// We log these base keys at channel opening to being able to rebuild redeemscript in case of leaked revoked commit tx
+ pub(super) fn set_their_base_keys(&mut self, their_htlc_base_key: &PublicKey, their_delayed_payment_base_key: &PublicKey) {
self.their_htlc_base_key = Some(their_htlc_base_key.clone());
+ self.their_delayed_payment_base_key = Some(their_delayed_payment_base_key.clone());
}
pub(super) fn set_their_to_self_delay(&mut self, their_to_self_delay: u16) {
self.funding_txo = None;
}
+ /// Gets the funding transaction outpoint of the channel this ChannelMonitor is monitoring for.
pub fn get_funding_txo(&self) -> Option<OutPoint> {
match self.funding_txo {
Some((outpoint, _)) => Some(outpoint),
res.extend_from_slice(&self.delayed_payment_base_key.serialize());
res.extend_from_slice(&self.their_htlc_base_key.as_ref().unwrap().serialize());
+ res.extend_from_slice(&self.their_delayed_payment_base_key.as_ref().unwrap().serialize());
match self.their_cur_revocation_points {
Some((idx, pubkey, second_option)) => {
let delayed_payment_base_key = unwrap_obj!(PublicKey::from_slice(&secp_ctx, read_bytes!(33)));
let their_htlc_base_key = Some(unwrap_obj!(PublicKey::from_slice(&secp_ctx, read_bytes!(33))));
+ let their_delayed_payment_base_key = Some(unwrap_obj!(PublicKey::from_slice(&secp_ctx, read_bytes!(33))));
let their_cur_revocation_points = {
let first_idx = byte_utils::slice_to_be48(read_bytes!(6));
key_storage,
delayed_payment_base_key,
their_htlc_base_key,
+ their_delayed_payment_base_key,
their_cur_revocation_points,
our_to_self_delay,
//we want to leave out (eg funding_txo, etc).
/// Can only fail if idx is < get_min_seen_secret
- pub fn get_secret(&self, idx: u64) -> Result<[u8; 32], HandleError> {
+ pub(super) fn get_secret(&self, idx: u64) -> Result<[u8; 32], HandleError> {
for i in 0..self.old_secrets.len() {
if (idx & (!((1 << i) - 1))) == self.old_secrets[i].1 {
return Ok(ChannelMonitor::derive_secret(self.old_secrets[i].0, i as u8, idx))
Err(HandleError{err: "idx too low", action: None})
}
- pub fn get_min_seen_secret(&self) -> u64 {
+ pub(super) fn get_min_seen_secret(&self) -> u64 {
//TODO This can be optimized?
let mut min = 1 << 48;
for &(_, idx) in self.old_secrets.iter() {
/// Attempts to claim a remote commitment transaction's outputs using the revocation key and
/// data in remote_claimable_outpoints. Will directly claim any HTLC outputs which expire at a
/// height > height + CLTV_SHARED_CLAIM_BUFFER. In any case, will install monitoring for
- /// HTLC-Success/HTLC-Timeout transactions, and claim them using the revocation key (if
- /// applicable) as well.
+ /// HTLC-Success/HTLC-Timeout transactions.
fn check_spend_remote_transaction(&self, tx: &Transaction, height: u32) -> (Vec<Transaction>, (Sha256dHash, Vec<TxOut>)) {
// Most secp and related errors trying to create keys means we have no hope of constructing
// a spend transaction...so we return no transactions to broadcast
txn_to_broadcast.push(spend_tx);
}
}
- } else {
- //TODO: For each input check if its in our remote_commitment_txn_on_chain map!
}
(txn_to_broadcast, (commitment_txid, watch_outputs))
}
+ /// Attempst to claim a remote HTLC-Success/HTLC-Timeout s outputs using the revocation key
+ fn check_spend_remote_htlc(&self, tx: &Transaction, commitment_number: u64) -> Option<Transaction> {
+ let htlc_txid = tx.txid(); //TODO: This is gonna be a performance bottleneck for watchtowers!
+
+ macro_rules! ignore_error {
+ ( $thing : expr ) => {
+ match $thing {
+ Ok(a) => a,
+ Err(_) => return None
+ }
+ };
+ }
+
+ let secret = ignore_error!(self.get_secret(commitment_number));
+ let per_commitment_key = ignore_error!(SecretKey::from_slice(&self.secp_ctx, &secret));
+ let per_commitment_point = PublicKey::from_secret_key(&self.secp_ctx, &per_commitment_key);
+ let revocation_pubkey = match self.key_storage {
+ KeyStorage::PrivMode { ref revocation_base_key, .. } => {
+ ignore_error!(chan_utils::derive_public_revocation_key(&self.secp_ctx, &per_commitment_point, &PublicKey::from_secret_key(&self.secp_ctx, &revocation_base_key)))
+ },
+ KeyStorage::SigsMode { ref revocation_base_key, .. } => {
+ ignore_error!(chan_utils::derive_public_revocation_key(&self.secp_ctx, &per_commitment_point, &revocation_base_key))
+ },
+ };
+ let delayed_key = match self.their_delayed_payment_base_key {
+ None => return None,
+ Some(their_delayed_payment_base_key) => ignore_error!(chan_utils::derive_public_key(&self.secp_ctx, &per_commitment_point, &their_delayed_payment_base_key)),
+ };
+ let redeemscript = chan_utils::get_revokeable_redeemscript(&revocation_pubkey, self.their_to_self_delay.unwrap(), &delayed_key);
+ let revokeable_p2wsh = redeemscript.to_v0_p2wsh();
+
+ let mut inputs = Vec::new();
+ let mut amount = 0;
+
+ if tx.output[0].script_pubkey == revokeable_p2wsh { //HTLC transactions have one txin, one txout
+ inputs.push(TxIn {
+ previous_output: BitcoinOutPoint {
+ txid: htlc_txid,
+ vout: 0,
+ },
+ script_sig: Script::new(),
+ sequence: 0xfffffffd,
+ witness: Vec::new(),
+ });
+ amount = tx.output[0].value;
+ }
+
+ if !inputs.is_empty() {
+ let outputs = vec!(TxOut {
+ script_pubkey: self.destination_script.clone(),
+ value: amount, //TODO: - fee
+ });
+
+ let mut spend_tx = Transaction {
+ version: 2,
+ lock_time: 0,
+ input: inputs,
+ output: outputs,
+ };
+
+ let sighash_parts = bip143::SighashComponents::new(&spend_tx);
+
+ let sig = match self.key_storage {
+ KeyStorage::PrivMode { ref revocation_base_key, .. } => {
+ let sighash = ignore_error!(Message::from_slice(&sighash_parts.sighash_all(&spend_tx.input[0], &redeemscript, amount)[..]));
+ let revocation_key = ignore_error!(chan_utils::derive_private_revocation_key(&self.secp_ctx, &per_commitment_key, &revocation_base_key));
+ self.secp_ctx.sign(&sighash, &revocation_key)
+ }
+ KeyStorage::SigsMode { .. } => {
+ unimplemented!();
+ }
+ };
+ spend_tx.input[0].witness.push(sig.serialize_der(&self.secp_ctx).to_vec());
+ spend_tx.input[0].witness[0].push(SigHashType::All as u8);
+ spend_tx.input[0].witness.push(vec!(1));
+ spend_tx.input[0].witness.push(redeemscript.into_bytes());
+
+ Some(spend_tx)
+ } else { None }
+ }
+
fn broadcast_by_local_state(&self, local_tx: &LocalSignedTx) -> Vec<Transaction> {
let mut res = Vec::with_capacity(local_tx.htlc_outputs.len());
fn block_connected(&self, txn_matched: &[&Transaction], height: u32, broadcaster: &BroadcasterInterface)-> Vec<(Sha256dHash, Vec<TxOut>)> {
let mut watch_outputs = Vec::new();
for tx in txn_matched {
- for txin in tx.input.iter() {
- if self.funding_txo.is_none() || (txin.previous_output.txid == self.funding_txo.as_ref().unwrap().0.txid && txin.previous_output.vout == self.funding_txo.as_ref().unwrap().0.index as u32) {
- let (mut txn, new_outputs) = self.check_spend_remote_transaction(tx, height);
+ if tx.input.len() == 1 {
+ // Assuming our keys were not leaked (in which case we're screwed no matter what),
+ // commitment transactions and HTLC transactions will all only ever have one input,
+ // which is an easy way to filter out any potential non-matching txn for lazy
+ // filters.
+ let prevout = &tx.input[0].previous_output;
+ let mut txn: Vec<Transaction> = Vec::new();
+ if self.funding_txo.is_none() || (prevout.txid == self.funding_txo.as_ref().unwrap().0.txid && prevout.vout == self.funding_txo.as_ref().unwrap().0.index as u32) {
+ let (remote_txn, new_outputs) = self.check_spend_remote_transaction(tx, height);
+ txn = remote_txn;
if !new_outputs.1.is_empty() {
watch_outputs.push(new_outputs);
}
if txn.is_empty() {
txn = self.check_spend_local_transaction(tx, height);
}
- for tx in txn.iter() {
- broadcaster.broadcast_transaction(tx);
+ } else {
+ let remote_commitment_txn_on_chain = self.remote_commitment_txn_on_chain.lock().unwrap();
+ if let Some(commitment_number) = remote_commitment_txn_on_chain.get(&prevout.txid) {
+ if let Some(tx) = self.check_spend_remote_htlc(tx, *commitment_number) {
+ txn.push(tx);
+ }
}
}
+ for tx in txn.iter() {
+ broadcaster.broadcast_transaction(tx);
+ }
}
}
if let Some(ref cur_local_tx) = self.current_local_signed_commitment_tx {
watch_outputs
}
- pub fn would_broadcast_at_height(&self, height: u32) -> bool {
+ pub(super) fn would_broadcast_at_height(&self, height: u32) -> bool {
if let Some(ref cur_local_tx) = self.current_local_signed_commitment_tx {
for &(ref htlc, _, _) in cur_local_tx.htlc_outputs.iter() {
if htlc.cltv_expiry <= height + CLTV_CLAIM_BUFFER {
projects / rust-lightning / blobdiff