use bitcoin::blockdata::script::{Script, Builder};
use bitcoin::blockdata::opcodes;
use bitcoin::network::constants::Network;
+use bitcoin::psbt::PartiallySignedTransaction;
use bitcoin::util::bip32::{ExtendedPrivKey, ExtendedPubKey, ChildNumber};
use bitcoin::util::sighash;
(2, StaticPaymentOutput),
);
+impl SpendableOutputDescriptor {
+ /// Turns this into a [`bitcoin::psbt::Input`] which can be used to create a
+ /// [`PartiallySignedTransaction`] which spends the given descriptor.
+ ///
+ /// Note that this does not include any signatures, just the information required to
+ /// construct the transaction and sign it.
+ pub fn to_psbt_input(&self) -> bitcoin::psbt::Input {
+ match self {
+ SpendableOutputDescriptor::StaticOutput { output, .. } => {
+ // Is a standard P2WPKH, no need for witness script
+ bitcoin::psbt::Input {
+ witness_utxo: Some(output.clone()),
+ ..Default::default()
+ }
+ },
+ SpendableOutputDescriptor::DelayedPaymentOutput(descriptor) => {
+ // TODO we could add the witness script as well
+ bitcoin::psbt::Input {
+ witness_utxo: Some(descriptor.output.clone()),
+ ..Default::default()
+ }
+ },
+ SpendableOutputDescriptor::StaticPaymentOutput(descriptor) => {
+ // TODO we could add the witness script as well
+ bitcoin::psbt::Input {
+ witness_utxo: Some(descriptor.output.clone()),
+ ..Default::default()
+ }
+ },
+ }
+ }
+
+ /// Creates an unsigned [`PartiallySignedTransaction`] which spends the given descriptors to
+ /// the given outputs, plus an output to the given change destination (if sufficient
+ /// change value remains). The PSBT will have a feerate, at least, of the given value.
+ ///
+ /// The `locktime` argument is used to set the transaction's locktime. If `None`, the
+ /// transaction will have a locktime of 0. It it recommended to set this to the current block
+ /// height to avoid fee sniping, unless you have some specific reason to use a different
+ /// locktime.
+ ///
+ /// Returns the PSBT and expected max transaction weight.
+ ///
+ /// Returns `Err(())` if the output value is greater than the input value minus required fee,
+ /// if a descriptor was duplicated, or if an output descriptor `script_pubkey`
+ /// does not match the one we can spend.
+ ///
+ /// We do not enforce that outputs meet the dust limit or that any output scripts are standard.
+ pub fn create_spendable_outputs_psbt(descriptors: &[&SpendableOutputDescriptor], outputs: Vec<TxOut>, change_destination_script: Script, feerate_sat_per_1000_weight: u32, locktime: Option<PackedLockTime>) -> Result<(PartiallySignedTransaction, usize), ()> {
+ let mut input = Vec::with_capacity(descriptors.len());
+ let mut input_value = 0;
+ let mut witness_weight = 0;
+ let mut output_set = HashSet::with_capacity(descriptors.len());
+ for outp in descriptors {
+ match outp {
+ SpendableOutputDescriptor::StaticPaymentOutput(descriptor) => {
+ if !output_set.insert(descriptor.outpoint) { return Err(()); }
+ input.push(TxIn {
+ previous_output: descriptor.outpoint.into_bitcoin_outpoint(),
+ script_sig: Script::new(),
+ sequence: Sequence::ZERO,
+ witness: Witness::new(),
+ });
+ witness_weight += StaticPaymentOutputDescriptor::MAX_WITNESS_LENGTH;
+ #[cfg(feature = "grind_signatures")]
+ { witness_weight -= 1; } // Guarantees a low R signature
+ input_value += descriptor.output.value;
+ },
+ SpendableOutputDescriptor::DelayedPaymentOutput(descriptor) => {
+ if !output_set.insert(descriptor.outpoint) { return Err(()); }
+ input.push(TxIn {
+ previous_output: descriptor.outpoint.into_bitcoin_outpoint(),
+ script_sig: Script::new(),
+ sequence: Sequence(descriptor.to_self_delay as u32),
+ witness: Witness::new(),
+ });
+ witness_weight += DelayedPaymentOutputDescriptor::MAX_WITNESS_LENGTH;
+ #[cfg(feature = "grind_signatures")]
+ { witness_weight -= 1; } // Guarantees a low R signature
+ input_value += descriptor.output.value;
+ },
+ SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output } => {
+ if !output_set.insert(*outpoint) { return Err(()); }
+ input.push(TxIn {
+ previous_output: outpoint.into_bitcoin_outpoint(),
+ script_sig: Script::new(),
+ sequence: Sequence::ZERO,
+ witness: Witness::new(),
+ });
+ witness_weight += 1 + 73 + 34;
+ #[cfg(feature = "grind_signatures")]
+ { witness_weight -= 1; } // Guarantees a low R signature
+ input_value += output.value;
+ }
+ }
+ if input_value > MAX_VALUE_MSAT / 1000 { return Err(()); }
+ }
+ let mut tx = Transaction {
+ version: 2,
+ lock_time: locktime.unwrap_or(PackedLockTime::ZERO),
+ input,
+ output: outputs,
+ };
+ let expected_max_weight =
+ transaction_utils::maybe_add_change_output(&mut tx, input_value, witness_weight, feerate_sat_per_1000_weight, change_destination_script)?;
+
+ let psbt_inputs = descriptors.iter().map(|d| d.to_psbt_input()).collect::<Vec<_>>();
+ let psbt = PartiallySignedTransaction {
+ inputs: psbt_inputs,
+ outputs: vec![Default::default(); tx.output.len()],
+ unsigned_tx: tx,
+ xpub: Default::default(),
+ version: 0,
+ proprietary: Default::default(),
+ unknown: Default::default(),
+ };
+ Ok((psbt, expected_max_weight))
+ }
+}
+
/// A trait to handle Lightning channel key material without concretizing the channel type or
/// the signature mechanism.
pub trait ChannelSigner {
)
}
- /// Creates a [`Transaction`] which spends the given descriptors to the given outputs, plus an
- /// output to the given change destination (if sufficient change value remains). The
- /// transaction will have a feerate, at least, of the given value.
+ /// Signs the given [`PartiallySignedTransaction`] which spends the given [`SpendableOutputDescriptor`]s.
+ /// The resulting inputs will be finalized and the PSBT will be ready for broadcast if there
+ /// are no other inputs that need signing.
///
- /// Returns `Err(())` if the output value is greater than the input value minus required fee,
- /// if a descriptor was duplicated, or if an output descriptor `script_pubkey`
- /// does not match the one we can spend.
- ///
- /// We do not enforce that outputs meet the dust limit or that any output scripts are standard.
+ /// Returns `Err(())` if the PSBT is missing a descriptor or if we fail to sign.
///
/// May panic if the [`SpendableOutputDescriptor`]s were not generated by channels which used
/// this [`KeysManager`] or one of the [`InMemorySigner`] created by this [`KeysManager`].
- pub fn spend_spendable_outputs<C: Signing>(&self, descriptors: &[&SpendableOutputDescriptor], outputs: Vec<TxOut>, change_destination_script: Script, feerate_sat_per_1000_weight: u32, secp_ctx: &Secp256k1<C>) -> Result<Transaction, ()> {
- let mut input = Vec::new();
- let mut input_value = 0;
- let mut witness_weight = 0;
- let mut output_set = HashSet::with_capacity(descriptors.len());
- for outp in descriptors {
- match outp {
- SpendableOutputDescriptor::StaticPaymentOutput(descriptor) => {
- input.push(TxIn {
- previous_output: descriptor.outpoint.into_bitcoin_outpoint(),
- script_sig: Script::new(),
- sequence: Sequence::ZERO,
- witness: Witness::new(),
- });
- witness_weight += StaticPaymentOutputDescriptor::MAX_WITNESS_LENGTH;
- #[cfg(feature = "grind_signatures")]
- { witness_weight -= 1; } // Guarantees a low R signature
- input_value += descriptor.output.value;
- if !output_set.insert(descriptor.outpoint) { return Err(()); }
- },
- SpendableOutputDescriptor::DelayedPaymentOutput(descriptor) => {
- input.push(TxIn {
- previous_output: descriptor.outpoint.into_bitcoin_outpoint(),
- script_sig: Script::new(),
- sequence: Sequence(descriptor.to_self_delay as u32),
- witness: Witness::new(),
- });
- witness_weight += DelayedPaymentOutputDescriptor::MAX_WITNESS_LENGTH;
- #[cfg(feature = "grind_signatures")]
- { witness_weight -= 1; } // Guarantees a low R signature
- input_value += descriptor.output.value;
- if !output_set.insert(descriptor.outpoint) { return Err(()); }
- },
- SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output } => {
- input.push(TxIn {
- previous_output: outpoint.into_bitcoin_outpoint(),
- script_sig: Script::new(),
- sequence: Sequence::ZERO,
- witness: Witness::new(),
- });
- witness_weight += 1 + 73 + 34;
- #[cfg(feature = "grind_signatures")]
- { witness_weight -= 1; } // Guarantees a low R signature
- input_value += output.value;
- if !output_set.insert(*outpoint) { return Err(()); }
- }
- }
- if input_value > MAX_VALUE_MSAT / 1000 { return Err(()); }
- }
- let mut spend_tx = Transaction {
- version: 2,
- lock_time: PackedLockTime(0),
- input,
- output: outputs,
- };
- let expected_max_weight =
- transaction_utils::maybe_add_change_output(&mut spend_tx, input_value, witness_weight, feerate_sat_per_1000_weight, change_destination_script)?;
-
+ pub fn sign_spendable_outputs_psbt<C: Signing>(&self, descriptors: &[&SpendableOutputDescriptor], psbt: &mut PartiallySignedTransaction, secp_ctx: &Secp256k1<C>) -> Result<(), ()> {
let mut keys_cache: Option<(InMemorySigner, [u8; 32])> = None;
- let mut input_idx = 0;
for outp in descriptors {
match outp {
SpendableOutputDescriptor::StaticPaymentOutput(descriptor) => {
+ let input_idx = psbt.unsigned_tx.input.iter().position(|i| i.previous_output == descriptor.outpoint.into_bitcoin_outpoint()).ok_or(())?;
if keys_cache.is_none() || keys_cache.as_ref().unwrap().1 != descriptor.channel_keys_id {
keys_cache = Some((
self.derive_channel_keys(descriptor.channel_value_satoshis, &descriptor.channel_keys_id),
descriptor.channel_keys_id));
}
- spend_tx.input[input_idx].witness = Witness::from_vec(keys_cache.as_ref().unwrap().0.sign_counterparty_payment_input(&spend_tx, input_idx, &descriptor, &secp_ctx)?);
+ let witness = Witness::from_vec(keys_cache.as_ref().unwrap().0.sign_counterparty_payment_input(&psbt.unsigned_tx, input_idx, &descriptor, &secp_ctx)?);
+ psbt.inputs[input_idx].final_script_witness = Some(witness);
},
SpendableOutputDescriptor::DelayedPaymentOutput(descriptor) => {
+ let input_idx = psbt.unsigned_tx.input.iter().position(|i| i.previous_output == descriptor.outpoint.into_bitcoin_outpoint()).ok_or(())?;
if keys_cache.is_none() || keys_cache.as_ref().unwrap().1 != descriptor.channel_keys_id {
keys_cache = Some((
self.derive_channel_keys(descriptor.channel_value_satoshis, &descriptor.channel_keys_id),
descriptor.channel_keys_id));
}
- spend_tx.input[input_idx].witness = Witness::from_vec(keys_cache.as_ref().unwrap().0.sign_dynamic_p2wsh_input(&spend_tx, input_idx, &descriptor, &secp_ctx)?);
+ let witness = Witness::from_vec(keys_cache.as_ref().unwrap().0.sign_dynamic_p2wsh_input(&psbt.unsigned_tx, input_idx, &descriptor, &secp_ctx)?);
+ psbt.inputs[input_idx].final_script_witness = Some(witness);
},
- SpendableOutputDescriptor::StaticOutput { ref output, .. } => {
+ SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output } => {
+ let input_idx = psbt.unsigned_tx.input.iter().position(|i| i.previous_output == outpoint.into_bitcoin_outpoint()).ok_or(())?;
let derivation_idx = if output.script_pubkey == self.destination_script {
1
} else {
if payment_script != output.script_pubkey { return Err(()); };
- let sighash = hash_to_message!(&sighash::SighashCache::new(&spend_tx).segwit_signature_hash(input_idx, &witness_script, output.value, EcdsaSighashType::All).unwrap()[..]);
+ let sighash = hash_to_message!(&sighash::SighashCache::new(&psbt.unsigned_tx).segwit_signature_hash(input_idx, &witness_script, output.value, EcdsaSighashType::All).unwrap()[..]);
let sig = sign_with_aux_rand(secp_ctx, &sighash, &secret.private_key, &self);
let mut sig_ser = sig.serialize_der().to_vec();
sig_ser.push(EcdsaSighashType::All as u8);
- spend_tx.input[input_idx].witness.push(sig_ser);
- spend_tx.input[input_idx].witness.push(pubkey.inner.serialize().to_vec());
+ let witness = Witness::from_vec(vec![sig_ser, pubkey.inner.serialize().to_vec()]);
+ psbt.inputs[input_idx].final_script_witness = Some(witness);
},
}
- input_idx += 1;
}
+ Ok(())
+ }
+
+ /// Creates a [`Transaction`] which spends the given descriptors to the given outputs, plus an
+ /// output to the given change destination (if sufficient change value remains). The
+ /// transaction will have a feerate, at least, of the given value.
+ ///
+ /// The `locktime` argument is used to set the transaction's locktime. If `None`, the
+ /// transaction will have a locktime of 0. It it recommended to set this to the current block
+ /// height to avoid fee sniping, unless you have some specific reason to use a different
+ /// locktime.
+ ///
+ /// Returns `Err(())` if the output value is greater than the input value minus required fee,
+ /// if a descriptor was duplicated, or if an output descriptor `script_pubkey`
+ /// does not match the one we can spend.
+ ///
+ /// We do not enforce that outputs meet the dust limit or that any output scripts are standard.
+ ///
+ /// May panic if the [`SpendableOutputDescriptor`]s were not generated by channels which used
+ /// this [`KeysManager`] or one of the [`InMemorySigner`] created by this [`KeysManager`].
+ pub fn spend_spendable_outputs<C: Signing>(&self, descriptors: &[&SpendableOutputDescriptor], outputs: Vec<TxOut>, change_destination_script: Script, feerate_sat_per_1000_weight: u32, locktime: Option<PackedLockTime>, secp_ctx: &Secp256k1<C>) -> Result<Transaction, ()> {
+ let (mut psbt, expected_max_weight) = SpendableOutputDescriptor::create_spendable_outputs_psbt(descriptors, outputs, change_destination_script, feerate_sat_per_1000_weight, locktime)?;
+ self.sign_spendable_outputs_psbt(descriptors, &mut psbt, secp_ctx)?;
+
+ let spend_tx = psbt.extract_tx();
+
debug_assert!(expected_max_weight >= spend_tx.weight());
// Note that witnesses with a signature vary somewhat in size, so allow
// `expected_max_weight` to overshoot by up to 3 bytes per input.
}
/// See [`KeysManager::spend_spendable_outputs`] for documentation on this method.
- pub fn spend_spendable_outputs<C: Signing>(&self, descriptors: &[&SpendableOutputDescriptor], outputs: Vec<TxOut>, change_destination_script: Script, feerate_sat_per_1000_weight: u32, secp_ctx: &Secp256k1<C>) -> Result<Transaction, ()> {
- self.inner.spend_spendable_outputs(descriptors, outputs, change_destination_script, feerate_sat_per_1000_weight, secp_ctx)
+ pub fn spend_spendable_outputs<C: Signing>(&self, descriptors: &[&SpendableOutputDescriptor], outputs: Vec<TxOut>, change_destination_script: Script, feerate_sat_per_1000_weight: u32, locktime: Option<PackedLockTime>, secp_ctx: &Secp256k1<C>) -> Result<Transaction, ()> {
+ self.inner.spend_spendable_outputs(descriptors, outputs, change_destination_script, feerate_sat_per_1000_weight, locktime, secp_ctx)
}
/// See [`KeysManager::derive_channel_keys`] for documentation on this method.
projects / rust-lightning / commitdiff