/// channel's monitor everywhere (including remote watchtowers) *before* this function returns. If
/// an update occurs and a remote watchtower is left with old state, it may broadcast transactions
/// which we have revoked, allowing our counterparty to claim all funds in the channel!
-/// A call to add_update_monitor is needed to register outpoint and its txid with ChainWatchInterface
-/// after setting funding_txo in a ChannelMonitor
pub trait ManyChannelMonitor: Send + Sync {
/// Adds or updates a monitor for the given `funding_txo`.
+ /// Implementor must also ensure that the funding_txo outpoint is registered with any relevant
+ /// ChainWatchInterfaces such that the provided monitor receives block_connected callbacks with
+ /// any spends of it.
fn add_update_monitor(&self, funding_txo: OutPoint, monitor: ChannelMonitor) -> Result<(), ChannelMonitorUpdateErr>;
}
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 ||
},
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,
/// optional, without it this monitor cannot be used in an SPV client, but you may wish to
/// avoid this (or call unset_funding_info) on a monitor you wish to send to a watchtower as it
/// provides slightly better privacy.
- /// It's the responsability of the caller to register outpoint and script with passing the former
+ /// It's the responsibility of the caller to register outpoint and script with passing the former
/// value as key to add_update_monitor.
pub(super) fn set_funding_info(&mut self, funding_info: (OutPoint, Script)) {
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) {
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,
/// 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 = self.get_secret(commitment_number).unwrap();
+ 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 {