//! The logic to build claims and bump in-flight transactions until confirmations.
//!
-//! OnchainTxHandler objetcs are fully-part of ChannelMonitor and encapsulates all
+//! OnchainTxHandler objects are fully-part of ChannelMonitor and encapsulates all
//! building, tracking, bumping and notifications functions.
use bitcoin::blockdata::transaction::{Transaction, TxIn, TxOut, SigHashType};
use ln::msgs::DecodeError;
use ln::channelmanager::PaymentPreimage;
use ln::chan_utils;
-use ln::chan_utils::{TxCreationKeys, HolderCommitmentTransaction};
+use ln::chan_utils::{TxCreationKeys, ChannelTransactionParameters, HolderCommitmentTransaction};
use chain::chaininterface::{FeeEstimator, BroadcasterInterface, ConfirmationTarget, MIN_RELAY_FEE_SAT_PER_1000_WEIGHT};
use chain::channelmonitor::{ANTI_REORG_DELAY, CLTV_SHARED_CLAIM_BUFFER, InputMaterial, ClaimRequest};
-use chain::keysinterface::ChannelKeys;
+use chain::keysinterface::{Sign, KeysInterface};
use util::logger::Logger;
-use util::ser::{Readable, Writer, Writeable};
+use util::ser::{Readable, ReadableArgs, Writer, Writeable, VecWriter};
use util::byte_utils;
use std::collections::{HashMap, hash_map};
use std::cmp;
use std::ops::Deref;
+use std::mem::replace;
const MAX_ALLOC_SIZE: usize = 64*1024;
/// OnchainTxHandler receives claiming requests, aggregates them if it's sound, broadcast and
/// do RBF bumping if possible.
-pub struct OnchainTxHandler<ChanSigner: ChannelKeys> {
+pub struct OnchainTxHandler<ChannelSigner: Sign> {
destination_script: Script,
- holder_commitment: Option<HolderCommitmentTransaction>,
+ holder_commitment: HolderCommitmentTransaction,
// holder_htlc_sigs and prev_holder_htlc_sigs are in the order as they appear in the commitment
// transaction outputs (hence the Option<>s inside the Vec). The first usize is the index in
- // the set of HTLCs in the HolderCommitmentTransaction (including those which do not appear in
- // the commitment transaction).
+ // the set of HTLCs in the HolderCommitmentTransaction.
holder_htlc_sigs: Option<Vec<Option<(usize, Signature)>>>,
prev_holder_commitment: Option<HolderCommitmentTransaction>,
prev_holder_htlc_sigs: Option<Vec<Option<(usize, Signature)>>>,
- on_holder_tx_csv: u16,
- key_storage: ChanSigner,
+ signer: ChannelSigner,
+ pub(crate) channel_transaction_parameters: ChannelTransactionParameters,
// Used to track claiming requests. If claim tx doesn't confirm before height timer expiration we need to bump
// it (RBF or CPFP). If an input has been part of an aggregate tx at first claim try, we need to keep it within
secp_ctx: Secp256k1<secp256k1::All>,
}
-impl<ChanSigner: ChannelKeys + Writeable> OnchainTxHandler<ChanSigner> {
+impl<ChannelSigner: Sign> OnchainTxHandler<ChannelSigner> {
pub(crate) fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
self.destination_script.write(writer)?;
self.holder_commitment.write(writer)?;
self.prev_holder_commitment.write(writer)?;
self.prev_holder_htlc_sigs.write(writer)?;
- self.on_holder_tx_csv.write(writer)?;
+ self.channel_transaction_parameters.write(writer)?;
- self.key_storage.write(writer)?;
+ let mut key_data = VecWriter(Vec::new());
+ self.signer.write(&mut key_data)?;
+ assert!(key_data.0.len() < std::usize::MAX);
+ assert!(key_data.0.len() < std::u32::MAX as usize);
+ (key_data.0.len() as u32).write(writer)?;
+ writer.write_all(&key_data.0[..])?;
writer.write_all(&byte_utils::be64_to_array(self.pending_claim_requests.len() as u64))?;
for (ref ancestor_claim_txid, claim_tx_data) in self.pending_claim_requests.iter() {
}
}
-impl<ChanSigner: ChannelKeys + Readable> Readable for OnchainTxHandler<ChanSigner> {
- fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
+impl<'a, K: KeysInterface> ReadableArgs<&'a K> for OnchainTxHandler<K::Signer> {
+ fn read<R: ::std::io::Read>(reader: &mut R, keys_manager: &'a K) -> Result<Self, DecodeError> {
let destination_script = Readable::read(reader)?;
let holder_commitment = Readable::read(reader)?;
let prev_holder_commitment = Readable::read(reader)?;
let prev_holder_htlc_sigs = Readable::read(reader)?;
- let on_holder_tx_csv = Readable::read(reader)?;
+ let channel_parameters = Readable::read(reader)?;
- let key_storage = Readable::read(reader)?;
+ let keys_len: u32 = Readable::read(reader)?;
+ let mut keys_data = Vec::with_capacity(cmp::min(keys_len as usize, MAX_ALLOC_SIZE));
+ while keys_data.len() != keys_len as usize {
+ // Read 1KB at a time to avoid accidentally allocating 4GB on corrupted channel keys
+ let mut data = [0; 1024];
+ let read_slice = &mut data[0..cmp::min(1024, keys_len as usize - keys_data.len())];
+ reader.read_exact(read_slice)?;
+ keys_data.extend_from_slice(read_slice);
+ }
+ let signer = keys_manager.read_chan_signer(&keys_data)?;
let pending_claim_requests_len: u64 = Readable::read(reader)?;
let mut pending_claim_requests = HashMap::with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
holder_htlc_sigs,
prev_holder_commitment,
prev_holder_htlc_sigs,
- on_holder_tx_csv,
- key_storage,
+ signer,
+ channel_transaction_parameters: channel_parameters,
claimable_outpoints,
pending_claim_requests,
onchain_events_waiting_threshold_conf,
}
}
-impl<ChanSigner: ChannelKeys> OnchainTxHandler<ChanSigner> {
- pub(crate) fn new(destination_script: Script, keys: ChanSigner, on_holder_tx_csv: u16) -> Self {
-
- let key_storage = keys;
-
+impl<ChannelSigner: Sign> OnchainTxHandler<ChannelSigner> {
+ pub(crate) fn new(destination_script: Script, signer: ChannelSigner, channel_parameters: ChannelTransactionParameters, holder_commitment: HolderCommitmentTransaction) -> Self {
OnchainTxHandler {
destination_script,
- holder_commitment: None,
+ holder_commitment,
holder_htlc_sigs: None,
prev_holder_commitment: None,
prev_holder_htlc_sigs: None,
- on_holder_tx_csv,
- key_storage,
+ signer,
+ channel_transaction_parameters: channel_parameters,
pending_claim_requests: HashMap::new(),
claimable_outpoints: HashMap::new(),
onchain_events_waiting_threshold_conf: HashMap::new(),
/// Lightning security model (i.e being able to redeem/timeout HTLC or penalize coutnerparty onchain) lays on the assumption of claim transactions getting confirmed before timelock expiration
/// (CSV or CLTV following cases). In case of high-fee spikes, claim tx may stuck in the mempool, so you need to bump its feerate quickly using Replace-By-Fee or Child-Pay-For-Parent.
+ /// Panics if there are signing errors, because signing operations in reaction to on-chain events
+ /// are not expected to fail, and if they do, we may lose funds.
fn generate_claim_tx<F: Deref, L: Deref>(&mut self, height: u32, cached_claim_datas: &ClaimTxBumpMaterial, fee_estimator: &F, logger: &L) -> Option<(Option<u32>, u32, Transaction)>
where F::Target: FeeEstimator,
L::Target: Logger,
for (i, (outp, per_outp_material)) in cached_claim_datas.per_input_material.iter().enumerate() {
match per_outp_material {
&InputMaterial::Revoked { ref per_commitment_point, ref counterparty_delayed_payment_base_key, ref counterparty_htlc_base_key, ref per_commitment_key, ref input_descriptor, ref amount, ref htlc, ref on_counterparty_tx_csv } => {
- if let Ok(chan_keys) = TxCreationKeys::derive_new(&self.secp_ctx, &per_commitment_point, counterparty_delayed_payment_base_key, counterparty_htlc_base_key, &self.key_storage.pubkeys().revocation_basepoint, &self.key_storage.pubkeys().htlc_basepoint) {
+ if let Ok(tx_keys) = TxCreationKeys::derive_new(&self.secp_ctx, &per_commitment_point, counterparty_delayed_payment_base_key, counterparty_htlc_base_key, &self.signer.pubkeys().revocation_basepoint, &self.signer.pubkeys().htlc_basepoint) {
let witness_script = if let Some(ref htlc) = *htlc {
- chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, &chan_keys.broadcaster_htlc_key, &chan_keys.countersignatory_htlc_key, &chan_keys.revocation_key)
+ chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, &tx_keys.broadcaster_htlc_key, &tx_keys.countersignatory_htlc_key, &tx_keys.revocation_key)
} else {
- chan_utils::get_revokeable_redeemscript(&chan_keys.revocation_key, *on_counterparty_tx_csv, &chan_keys.broadcaster_delayed_payment_key)
+ chan_utils::get_revokeable_redeemscript(&tx_keys.revocation_key, *on_counterparty_tx_csv, &tx_keys.broadcaster_delayed_payment_key)
};
- if let Ok(sig) = self.key_storage.sign_justice_transaction(&bumped_tx, i, *amount, &per_commitment_key, htlc, &self.secp_ctx) {
- bumped_tx.input[i].witness.push(sig.serialize_der().to_vec());
- bumped_tx.input[i].witness[0].push(SigHashType::All as u8);
- if htlc.is_some() {
- bumped_tx.input[i].witness.push(chan_keys.revocation_key.clone().serialize().to_vec());
- } else {
- bumped_tx.input[i].witness.push(vec!(1));
- }
- bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
- } else { return None; }
- //TODO: panic ?
+ let sig = self.signer.sign_justice_transaction(&bumped_tx, i, *amount, &per_commitment_key, htlc, &self.secp_ctx).expect("sign justice tx");
+ bumped_tx.input[i].witness.push(sig.serialize_der().to_vec());
+ bumped_tx.input[i].witness[0].push(SigHashType::All as u8);
+ if htlc.is_some() {
+ bumped_tx.input[i].witness.push(tx_keys.revocation_key.clone().serialize().to_vec());
+ } else {
+ bumped_tx.input[i].witness.push(vec!(1));
+ }
+ bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
log_trace!(logger, "Going to broadcast Penalty Transaction {} claiming revoked {} output {} from {} with new feerate {}...", bumped_tx.txid(), if *input_descriptor == InputDescriptors::RevokedOutput { "to_holder" } else if *input_descriptor == InputDescriptors::RevokedOfferedHTLC { "offered" } else if *input_descriptor == InputDescriptors::RevokedReceivedHTLC { "received" } else { "" }, outp.vout, outp.txid, new_feerate);
}
},
&InputMaterial::CounterpartyHTLC { ref per_commitment_point, ref counterparty_delayed_payment_base_key, ref counterparty_htlc_base_key, ref preimage, ref htlc } => {
- if let Ok(chan_keys) = TxCreationKeys::derive_new(&self.secp_ctx, &per_commitment_point, counterparty_delayed_payment_base_key, counterparty_htlc_base_key, &self.key_storage.pubkeys().revocation_basepoint, &self.key_storage.pubkeys().htlc_basepoint) {
- let witness_script = chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, &chan_keys.broadcaster_htlc_key, &chan_keys.countersignatory_htlc_key, &chan_keys.revocation_key);
+ if let Ok(tx_keys) = TxCreationKeys::derive_new(&self.secp_ctx, &per_commitment_point, counterparty_delayed_payment_base_key, counterparty_htlc_base_key, &self.signer.pubkeys().revocation_basepoint, &self.signer.pubkeys().htlc_basepoint) {
+ let witness_script = chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, &tx_keys.broadcaster_htlc_key, &tx_keys.countersignatory_htlc_key, &tx_keys.revocation_key);
if !preimage.is_some() { bumped_tx.lock_time = htlc.cltv_expiry }; // Right now we don't aggregate time-locked transaction, if we do we should set lock_time before to avoid breaking hash computation
- if let Ok(sig) = self.key_storage.sign_counterparty_htlc_transaction(&bumped_tx, i, &htlc.amount_msat / 1000, &per_commitment_point, htlc, &self.secp_ctx) {
- bumped_tx.input[i].witness.push(sig.serialize_der().to_vec());
- bumped_tx.input[i].witness[0].push(SigHashType::All as u8);
- if let &Some(preimage) = preimage {
- bumped_tx.input[i].witness.push(preimage.0.to_vec());
- } else {
- // Due to BIP146 (MINIMALIF) this must be a zero-length element to relay.
- bumped_tx.input[i].witness.push(vec![]);
- }
- bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
+ let sig = self.signer.sign_counterparty_htlc_transaction(&bumped_tx, i, &htlc.amount_msat / 1000, &per_commitment_point, htlc, &self.secp_ctx).expect("sign counterparty HTLC tx");
+ bumped_tx.input[i].witness.push(sig.serialize_der().to_vec());
+ bumped_tx.input[i].witness[0].push(SigHashType::All as u8);
+ if let &Some(preimage) = preimage {
+ bumped_tx.input[i].witness.push(preimage.0.to_vec());
+ } else {
+ // Due to BIP146 (MINIMALIF) this must be a zero-length element to relay.
+ bumped_tx.input[i].witness.push(vec![]);
}
+ bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
log_trace!(logger, "Going to broadcast Claim Transaction {} claiming counterparty {} htlc output {} from {} with new feerate {}...", bumped_tx.txid(), if preimage.is_some() { "offered" } else { "received" }, outp.vout, outp.txid, new_feerate);
}
},
return None;
},
&InputMaterial::Funding { ref funding_redeemscript } => {
- let signed_tx = self.get_fully_signed_holder_tx(funding_redeemscript).unwrap();
+ let signed_tx = self.get_fully_signed_holder_tx(funding_redeemscript);
// Timer set to $NEVER given we can't bump tx without anchor outputs
log_trace!(logger, "Going to broadcast Holder Transaction {} claiming funding output {} from {}...", signed_tx.txid(), outp.vout, outp.txid);
- return Some((None, self.holder_commitment.as_ref().unwrap().feerate_per_kw, signed_tx));
+ return Some((None, self.holder_commitment.feerate_per_kw(), signed_tx));
}
_ => unreachable!()
}
}
pub(crate) fn provide_latest_holder_tx(&mut self, tx: HolderCommitmentTransaction) {
- self.prev_holder_commitment = self.holder_commitment.take();
- self.holder_commitment = Some(tx);
+ self.prev_holder_commitment = Some(replace(&mut self.holder_commitment, tx));
+ self.holder_htlc_sigs = None;
}
+ // Normally holder HTLCs are signed at the same time as the holder commitment tx. However,
+ // in some configurations, the holder commitment tx has been signed and broadcast by a
+ // ChannelMonitor replica, so we handle that case here.
fn sign_latest_holder_htlcs(&mut self) {
- if let Some(ref holder_commitment) = self.holder_commitment {
- if let Ok(sigs) = self.key_storage.sign_holder_commitment_htlc_transactions(holder_commitment, &self.secp_ctx) {
- self.holder_htlc_sigs = Some(Vec::new());
- let ret = self.holder_htlc_sigs.as_mut().unwrap();
- for (htlc_idx, (holder_sig, &(ref htlc, _))) in sigs.iter().zip(holder_commitment.per_htlc.iter()).enumerate() {
- if let Some(tx_idx) = htlc.transaction_output_index {
- if ret.len() <= tx_idx as usize { ret.resize(tx_idx as usize + 1, None); }
- ret[tx_idx as usize] = Some((htlc_idx, holder_sig.expect("Did not receive a signature for a non-dust HTLC")));
- } else {
- assert!(holder_sig.is_none(), "Received a signature for a dust HTLC");
- }
- }
- }
+ if self.holder_htlc_sigs.is_none() {
+ let (_sig, sigs) = self.signer.sign_holder_commitment_and_htlcs(&self.holder_commitment, &self.secp_ctx).expect("sign holder commitment");
+ self.holder_htlc_sigs = Some(Self::extract_holder_sigs(&self.holder_commitment, sigs));
}
}
+
+ // Normally only the latest commitment tx and HTLCs need to be signed. However, in some
+ // configurations we may have updated our holder commitment but a replica of the ChannelMonitor
+ // broadcast the previous one before we sync with it. We handle that case here.
fn sign_prev_holder_htlcs(&mut self) {
- if let Some(ref holder_commitment) = self.prev_holder_commitment {
- if let Ok(sigs) = self.key_storage.sign_holder_commitment_htlc_transactions(holder_commitment, &self.secp_ctx) {
- self.prev_holder_htlc_sigs = Some(Vec::new());
- let ret = self.prev_holder_htlc_sigs.as_mut().unwrap();
- for (htlc_idx, (holder_sig, &(ref htlc, _))) in sigs.iter().zip(holder_commitment.per_htlc.iter()).enumerate() {
- if let Some(tx_idx) = htlc.transaction_output_index {
- if ret.len() <= tx_idx as usize { ret.resize(tx_idx as usize + 1, None); }
- ret[tx_idx as usize] = Some((htlc_idx, holder_sig.expect("Did not receive a signature for a non-dust HTLC")));
- } else {
- assert!(holder_sig.is_none(), "Received a signature for a dust HTLC");
- }
- }
+ if self.prev_holder_htlc_sigs.is_none() {
+ if let Some(ref holder_commitment) = self.prev_holder_commitment {
+ let (_sig, sigs) = self.signer.sign_holder_commitment_and_htlcs(holder_commitment, &self.secp_ctx).expect("sign previous holder commitment");
+ self.prev_holder_htlc_sigs = Some(Self::extract_holder_sigs(holder_commitment, sigs));
}
}
}
- //TODO: getting lastest holder transactions should be infaillible and result in us "force-closing the channel", but we may
+ fn extract_holder_sigs(holder_commitment: &HolderCommitmentTransaction, sigs: Vec<Signature>) -> Vec<Option<(usize, Signature)>> {
+ let mut ret = Vec::new();
+ for (htlc_idx, (holder_sig, htlc)) in sigs.iter().zip(holder_commitment.htlcs().iter()).enumerate() {
+ let tx_idx = htlc.transaction_output_index.unwrap();
+ if ret.len() <= tx_idx as usize { ret.resize(tx_idx as usize + 1, None); }
+ ret[tx_idx as usize] = Some((htlc_idx, holder_sig.clone()));
+ }
+ ret
+ }
+
+ //TODO: getting lastest holder transactions should be infallible and result in us "force-closing the channel", but we may
// have empty holder commitment transaction if a ChannelMonitor is asked to force-close just after Channel::get_outbound_funding_created,
// before providing a initial commitment transaction. For outbound channel, init ChannelMonitor at Channel::funding_signed, there is nothing
// to monitor before.
- pub(crate) fn get_fully_signed_holder_tx(&mut self, funding_redeemscript: &Script) -> Option<Transaction> {
- if let Some(ref mut holder_commitment) = self.holder_commitment {
- match self.key_storage.sign_holder_commitment(holder_commitment, &self.secp_ctx) {
- Ok(sig) => Some(holder_commitment.add_holder_sig(funding_redeemscript, sig)),
- Err(_) => return None,
- }
- } else {
- None
- }
+ pub(crate) fn get_fully_signed_holder_tx(&mut self, funding_redeemscript: &Script) -> Transaction {
+ let (sig, htlc_sigs) = self.signer.sign_holder_commitment_and_htlcs(&self.holder_commitment, &self.secp_ctx).expect("signing holder commitment");
+ self.holder_htlc_sigs = Some(Self::extract_holder_sigs(&self.holder_commitment, htlc_sigs));
+ self.holder_commitment.add_holder_sig(funding_redeemscript, sig)
}
#[cfg(any(test, feature="unsafe_revoked_tx_signing"))]
- pub(crate) fn get_fully_signed_copy_holder_tx(&mut self, funding_redeemscript: &Script) -> Option<Transaction> {
- if let Some(ref mut holder_commitment) = self.holder_commitment {
- let holder_commitment = holder_commitment.clone();
- match self.key_storage.sign_holder_commitment(&holder_commitment, &self.secp_ctx) {
- Ok(sig) => Some(holder_commitment.add_holder_sig(funding_redeemscript, sig)),
- Err(_) => return None,
- }
- } else {
- None
- }
+ pub(crate) fn get_fully_signed_copy_holder_tx(&mut self, funding_redeemscript: &Script) -> Transaction {
+ let (sig, htlc_sigs) = self.signer.unsafe_sign_holder_commitment_and_htlcs(&self.holder_commitment, &self.secp_ctx).expect("sign holder commitment");
+ self.holder_htlc_sigs = Some(Self::extract_holder_sigs(&self.holder_commitment, htlc_sigs));
+ self.holder_commitment.add_holder_sig(funding_redeemscript, sig)
}
pub(crate) fn get_fully_signed_htlc_tx(&mut self, outp: &::bitcoin::OutPoint, preimage: &Option<PaymentPreimage>) -> Option<Transaction> {
let mut htlc_tx = None;
- if self.holder_commitment.is_some() {
- let commitment_txid = self.holder_commitment.as_ref().unwrap().txid();
- if commitment_txid == outp.txid {
- self.sign_latest_holder_htlcs();
- if let &Some(ref htlc_sigs) = &self.holder_htlc_sigs {
- let &(ref htlc_idx, ref htlc_sig) = htlc_sigs[outp.vout as usize].as_ref().unwrap();
- htlc_tx = Some(self.holder_commitment.as_ref().unwrap()
- .get_signed_htlc_tx(*htlc_idx, htlc_sig, preimage, self.on_holder_tx_csv));
- }
+ let commitment_txid = self.holder_commitment.trust().txid();
+ // Check if the HTLC spends from the current holder commitment
+ if commitment_txid == outp.txid {
+ self.sign_latest_holder_htlcs();
+ if let &Some(ref htlc_sigs) = &self.holder_htlc_sigs {
+ let &(ref htlc_idx, ref htlc_sig) = htlc_sigs[outp.vout as usize].as_ref().unwrap();
+ let trusted_tx = self.holder_commitment.trust();
+ let counterparty_htlc_sig = self.holder_commitment.counterparty_htlc_sigs[*htlc_idx];
+ htlc_tx = Some(trusted_tx
+ .get_signed_htlc_tx(&self.channel_transaction_parameters.as_holder_broadcastable(), *htlc_idx, &counterparty_htlc_sig, htlc_sig, preimage));
}
}
- if self.prev_holder_commitment.is_some() {
- let commitment_txid = self.prev_holder_commitment.as_ref().unwrap().txid();
+ // If the HTLC doesn't spend the current holder commitment, check if it spends the previous one
+ if htlc_tx.is_none() && self.prev_holder_commitment.is_some() {
+ let commitment_txid = self.prev_holder_commitment.as_ref().unwrap().trust().txid();
if commitment_txid == outp.txid {
self.sign_prev_holder_htlcs();
if let &Some(ref htlc_sigs) = &self.prev_holder_htlc_sigs {
let &(ref htlc_idx, ref htlc_sig) = htlc_sigs[outp.vout as usize].as_ref().unwrap();
- htlc_tx = Some(self.prev_holder_commitment.as_ref().unwrap()
- .get_signed_htlc_tx(*htlc_idx, htlc_sig, preimage, self.on_holder_tx_csv));
+ let holder_commitment = self.prev_holder_commitment.as_ref().unwrap();
+ let trusted_tx = holder_commitment.trust();
+ let counterparty_htlc_sig = holder_commitment.counterparty_htlc_sigs[*htlc_idx];
+ htlc_tx = Some(trusted_tx
+ .get_signed_htlc_tx(&self.channel_transaction_parameters.as_holder_broadcastable(), *htlc_idx, &counterparty_htlc_sig, htlc_sig, preimage));
}
}
}