let chan_keys = TxCreationKeys::derive_new(&onchain_handler.secp_ctx, &outp.per_commitment_point, &outp.counterparty_delayed_payment_base_key, &outp.counterparty_htlc_base_key, &onchain_handler.signer.pubkeys().revocation_basepoint, &onchain_handler.signer.pubkeys().htlc_basepoint);
let witness_script = chan_utils::get_htlc_redeemscript_with_explicit_keys(&outp.htlc, onchain_handler.opt_anchors(), &chan_keys.broadcaster_htlc_key, &chan_keys.countersignatory_htlc_key, &chan_keys.revocation_key);
- bumped_tx.lock_time = PackedLockTime(outp.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) = onchain_handler.signer.sign_counterparty_htlc_transaction(&bumped_tx, i, &outp.htlc.amount_msat / 1000, &outp.per_commitment_point, &outp.htlc, &onchain_handler.secp_ctx) {
let mut ser_sig = sig.serialize_der().to_vec();
ser_sig.push(EcdsaSighashType::All as u8);
_ => { panic!("API Error!"); }
}
}
- fn absolute_tx_timelock(&self, output_conf_height: u32) -> u32 {
- // Get the absolute timelock at which this output can be spent given the height at which
- // this output was confirmed. We use `output_conf_height + 1` as a safe default as we can
- // be confirmed in the next block and transactions with time lock `current_height + 1`
- // always propagate.
+ fn absolute_tx_timelock(&self, current_height: u32) -> u32 {
+ // We use `current_height + 1` as our default locktime to discourage fee sniping and because
+ // transactions with it always propagate.
let absolute_timelock = match self {
- PackageSolvingData::RevokedOutput(_) => output_conf_height + 1,
- PackageSolvingData::RevokedHTLCOutput(_) => output_conf_height + 1,
- PackageSolvingData::CounterpartyOfferedHTLCOutput(_) => output_conf_height + 1,
- PackageSolvingData::CounterpartyReceivedHTLCOutput(ref outp) => cmp::max(outp.htlc.cltv_expiry, output_conf_height + 1),
- PackageSolvingData::HolderHTLCOutput(ref outp) => cmp::max(outp.cltv_expiry, output_conf_height + 1),
- PackageSolvingData::HolderFundingOutput(_) => output_conf_height + 1,
+ PackageSolvingData::RevokedOutput(_) => current_height + 1,
+ PackageSolvingData::RevokedHTLCOutput(_) => current_height + 1,
+ PackageSolvingData::CounterpartyOfferedHTLCOutput(_) => current_height + 1,
+ PackageSolvingData::CounterpartyReceivedHTLCOutput(ref outp) => cmp::max(outp.htlc.cltv_expiry, current_height + 1),
+ // HTLC timeout/success transactions rely on a fixed timelock due to the counterparty's
+ // signature.
+ PackageSolvingData::HolderHTLCOutput(ref outp) => {
+ if outp.preimage.is_some() {
+ debug_assert_eq!(outp.cltv_expiry, 0);
+ }
+ outp.cltv_expiry
+ },
+ PackageSolvingData::HolderFundingOutput(_) => current_height + 1,
};
absolute_timelock
}
}
amounts
}
- pub(crate) fn package_timelock(&self) -> u32 {
- self.inputs.iter().map(|(_, outp)| outp.absolute_tx_timelock(self.height_original))
- .max().expect("There must always be at least one output to spend in a PackageTemplate")
+ pub(crate) fn package_locktime(&self, current_height: u32) -> u32 {
+ let locktime = self.inputs.iter().map(|(_, outp)| outp.absolute_tx_timelock(current_height))
+ .max().expect("There must always be at least one output to spend in a PackageTemplate");
+
+ // If we ever try to aggregate a `HolderHTLCOutput`s with another output type, we'll likely
+ // end up with an incorrect transaction locktime since the counterparty has included it in
+ // its HTLC signature. This should never happen unless we decide to aggregate outputs across
+ // different channel commitments.
+ #[cfg(debug_assertions)] {
+ if self.inputs.iter().any(|(_, outp)|
+ if let PackageSolvingData::HolderHTLCOutput(outp) = outp {
+ outp.preimage.is_some()
+ } else {
+ false
+ }
+ ) {
+ debug_assert_eq!(locktime, 0);
+ };
+ for timeout_htlc_expiry in self.inputs.iter().filter_map(|(_, outp)|
+ if let PackageSolvingData::HolderHTLCOutput(outp) = outp {
+ if outp.preimage.is_none() {
+ Some(outp.cltv_expiry)
+ } else { None }
+ } else { None }
+ ) {
+ debug_assert_eq!(locktime, timeout_htlc_expiry);
+ }
+ }
+
+ locktime
}
pub(crate) fn package_weight(&self, destination_script: &Script) -> usize {
let mut inputs_weight = 0;
htlcs
}
pub(crate) fn finalize_malleable_package<L: Deref, Signer: WriteableEcdsaChannelSigner>(
- &self, onchain_handler: &mut OnchainTxHandler<Signer>, value: u64, destination_script: Script, logger: &L
+ &self, current_height: u32, onchain_handler: &mut OnchainTxHandler<Signer>, value: u64,
+ destination_script: Script, logger: &L
) -> Option<Transaction> where L::Target: Logger {
debug_assert!(self.is_malleable());
let mut bumped_tx = Transaction {
version: 2,
- lock_time: PackedLockTime::ZERO,
+ lock_time: PackedLockTime(self.package_locktime(current_height)),
input: vec![],
output: vec
projects / rust-lightning / blobdiff