}
/// Build a closing transaction
-pub fn build_closing_transaction(value_to_holder: u64, value_to_counterparty: u64, holder_shutdown_script: Script, counterparty_shutdown_script: Script, funding_outpoint: OutPoint) -> Transaction {
+pub fn build_closing_transaction(to_holder_value_sat: u64, to_counterparty_value_sat: u64, to_holder_script: Script, to_counterparty_script: Script, funding_outpoint: OutPoint) -> Transaction {
let txins = {
let mut ins: Vec<TxIn> = Vec::new();
ins.push(TxIn {
let mut txouts: Vec<(TxOut, ())> = Vec::new();
- if value_to_counterparty > 0 {
+ if to_counterparty_value_sat > 0 {
txouts.push((TxOut {
- script_pubkey: counterparty_shutdown_script,
- value: value_to_counterparty
+ script_pubkey: to_counterparty_script,
+ value: to_counterparty_value_sat
}, ()));
}
- if value_to_holder > 0 {
+ if to_holder_value_sat > 0 {
txouts.push((TxOut {
- script_pubkey: holder_shutdown_script,
- value: value_to_holder
+ script_pubkey: to_holder_script,
+ value: to_holder_value_sat
}, ()));
}
}
}
+/// Gets the witnessScript for the to_remote output when anchors are enabled.
+#[inline]
+pub(crate) fn get_to_countersignatory_with_anchors_redeemscript(payment_point: &PublicKey) -> Script {
+ Builder::new()
+ .push_slice(&payment_point.serialize()[..])
+ .push_opcode(opcodes::all::OP_CHECKSIGVERIFY)
+ .push_int(1)
+ .push_opcode(opcodes::all::OP_CSV)
+ .into_script()
+}
+
/// Gets the witnessScript for an anchor output from the funding public key.
/// The witness in the spending input must be:
/// <BIP 143 funding_signature>
}
}
-/// This class tracks the per-transaction information needed to build a commitment transaction and to
+/// This class tracks the per-transaction information needed to build a closing transaction and will
+/// actually build it and sign.
+///
+/// This class can be used inside a signer implementation to generate a signature given the relevant
+/// secret key.
+pub struct ClosingTransaction {
+ to_holder_value_sat: u64,
+ to_counterparty_value_sat: u64,
+ to_holder_script: Script,
+ to_counterparty_script: Script,
+ built: Transaction,
+}
+
+impl ClosingTransaction {
+ /// Construct an object of the class
+ pub fn new(
+ to_holder_value_sat: u64,
+ to_counterparty_value_sat: u64,
+ to_holder_script: Script,
+ to_counterparty_script: Script,
+ funding_outpoint: OutPoint,
+ ) -> Self {
+ let built = build_closing_transaction(
+ to_holder_value_sat, to_counterparty_value_sat,
+ to_holder_script.clone(), to_counterparty_script.clone(),
+ funding_outpoint
+ );
+ ClosingTransaction {
+ to_holder_value_sat,
+ to_counterparty_value_sat,
+ to_holder_script,
+ to_counterparty_script,
+ built
+ }
+ }
+
+ /// Trust our pre-built transaction.
+ ///
+ /// Applies a wrapper which allows access to the transaction.
+ ///
+ /// This should only be used if you fully trust the builder of this object. It should not
+ /// be used by an external signer - instead use the verify function.
+ pub fn trust(&self) -> TrustedClosingTransaction {
+ TrustedClosingTransaction { inner: self }
+ }
+
+ /// Verify our pre-built transaction.
+ ///
+ /// Applies a wrapper which allows access to the transaction.
+ ///
+ /// An external validating signer must call this method before signing
+ /// or using the built transaction.
+ pub fn verify(&self, funding_outpoint: OutPoint) -> Result<TrustedClosingTransaction, ()> {
+ let built = build_closing_transaction(
+ self.to_holder_value_sat, self.to_counterparty_value_sat,
+ self.to_holder_script.clone(), self.to_counterparty_script.clone(),
+ funding_outpoint
+ );
+ if self.built != built {
+ return Err(())
+ }
+ Ok(TrustedClosingTransaction { inner: self })
+ }
+
+ /// The value to be sent to the holder, or zero if the output will be omitted
+ pub fn to_holder_value_sat(&self) -> u64 {
+ self.to_holder_value_sat
+ }
+
+ /// The value to be sent to the counterparty, or zero if the output will be omitted
+ pub fn to_counterparty_value_sat(&self) -> u64 {
+ self.to_counterparty_value_sat
+ }
+
+ /// The destination of the holder's output
+ pub fn to_holder_script(&self) -> &Script {
+ &self.to_holder_script
+ }
+
+ /// The destination of the counterparty's output
+ pub fn to_counterparty_script(&self) -> &Script {
+ &self.to_counterparty_script
+ }
+}
+
+/// A wrapper on ClosingTransaction indicating that the built bitcoin
+/// transaction is trusted.
+///
+/// See trust() and verify() functions on CommitmentTransaction.
+///
+/// This structure implements Deref.
+pub struct TrustedClosingTransaction<'a> {
+ inner: &'a ClosingTransaction,
+}
+
+impl<'a> Deref for TrustedClosingTransaction<'a> {
+ type Target = ClosingTransaction;
+
+ fn deref(&self) -> &Self::Target { self.inner }
+}
+
+impl<'a> TrustedClosingTransaction<'a> {
+ /// The pre-built Bitcoin commitment transaction
+ pub fn built_transaction(&self) -> &Transaction {
+ &self.inner.built
+ }
+
+ /// Get the SIGHASH_ALL sighash value of the transaction.
+ ///
+ /// This can be used to verify a signature.
+ pub fn get_sighash_all(&self, funding_redeemscript: &Script, channel_value_satoshis: u64) -> Message {
+ let sighash = &bip143::SigHashCache::new(&self.inner.built).signature_hash(0, funding_redeemscript, channel_value_satoshis, SigHashType::All)[..];
+ hash_to_message!(sighash)
+ }
+
+ /// Sign a transaction, either because we are counter-signing the counterparty's transaction or
+ /// because we are about to broadcast a holder transaction.
+ pub fn sign<T: secp256k1::Signing>(&self, funding_key: &SecretKey, funding_redeemscript: &Script, channel_value_satoshis: u64, secp_ctx: &Secp256k1<T>) -> Signature {
+ let sighash = self.get_sighash_all(funding_redeemscript, channel_value_satoshis);
+ secp_ctx.sign(&sighash, funding_key)
+ }
+}
+
+/// This class tracks the per-transaction information needed to build a commitment transaction and will
/// actually build it and sign. It is used for holder transactions that we sign only when needed
/// and for transactions we sign for the counterparty.
///
let mut txouts: Vec<(TxOut, Option<&mut HTLCOutputInCommitment>)> = Vec::new();
if to_countersignatory_value_sat > 0 {
- let script = script_for_p2wpkh(&countersignatory_pubkeys.payment_point);
+ let script = if opt_anchors {
+ get_to_countersignatory_with_anchors_redeemscript(&countersignatory_pubkeys.payment_point).to_v0_p2wsh()
+ } else {
+ get_p2wpkh_redeemscript(&countersignatory_pubkeys.payment_point)
+ };
txouts.push((
TxOut {
script_pubkey: script.clone(),
/// Applies a wrapper which allows access to these fields.
///
/// This should only be used if you fully trust the builder of this object. It should not
- /// be used by an external signer - instead use the verify function.
+ /// be used by an external signer - instead use the verify function.
pub fn trust(&self) -> TrustedCommitmentTransaction {
TrustedCommitmentTransaction { inner: self }
}
| ((res[31] as u64) << 0 * 8)
}
-fn script_for_p2wpkh(key: &PublicKey) -> Script {
+fn get_p2wpkh_redeemscript(key: &PublicKey) -> Script {
Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0)
.push_slice(&WPubkeyHash::hash(&key.serialize())[..])
.into_script()
use super::CounterpartyCommitmentSecrets;
use ::{hex, chain};
use prelude::*;
- use ln::chan_utils::{CommitmentTransaction, TxCreationKeys, ChannelTransactionParameters, CounterpartyChannelTransactionParameters, HTLCOutputInCommitment};
+ use ln::chan_utils::{get_to_countersignatory_with_anchors_redeemscript, get_p2wpkh_redeemscript, CommitmentTransaction, TxCreationKeys, ChannelTransactionParameters, CounterpartyChannelTransactionParameters, HTLCOutputInCommitment};
use bitcoin::secp256k1::{PublicKey, SecretKey, Secp256k1};
use util::test_utils;
use chain::keysinterface::{KeysInterface, BaseSign};
&mut htlcs_with_aux, &channel_parameters.as_holder_broadcastable()
);
assert_eq!(tx.built.transaction.output.len(), 2);
+ assert_eq!(tx.built.transaction.output[1].script_pubkey, get_p2wpkh_redeemscript(&counterparty_pubkeys.payment_point));
// Generate broadcaster and counterparty outputs as well as two anchors
let tx = CommitmentTransaction::new_with_auxiliary_htlc_data(
&mut htlcs_with_aux, &channel_parameters.as_holder_broadcastable()
);
assert_eq!(tx.built.transaction.output.len(), 4);
+ assert_eq!(tx.built.transaction.output[3].script_pubkey, get_to_countersignatory_with_anchors_redeemscript(&counterparty_pubkeys.payment_point).to_v0_p2wsh());
// Generate broadcaster output and anchor
let tx = CommitmentTransaction::new_with_auxiliary_htlc_data(
projects / rust-lightning / blobdiff