use chain::transaction::OutPoint;
use ln::chan_utils;
-use ln::chan_utils::{HTLCOutputInCommitment, make_funding_redeemscript, ChannelPublicKeys, HolderCommitmentTransaction, ChannelTransactionParameters, CommitmentTransaction};
+use ln::chan_utils::{HTLCOutputInCommitment, make_funding_redeemscript, ChannelPublicKeys, HolderCommitmentTransaction, ChannelTransactionParameters, CommitmentTransaction, ClosingTransaction};
use ln::msgs::UnsignedChannelAnnouncement;
use ln::script::ShutdownScript;
///
/// Note that, due to rounding, there may be one "missing" satoshi, and either party may have
/// chosen to forgo their output as dust.
- fn sign_closing_transaction(&self, closing_tx: &Transaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()>;
+ fn sign_closing_transaction(&self, closing_tx: &ClosingTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()>;
/// Signs a channel announcement message with our funding key, proving it comes from one
/// of the channel participants.
Err(())
}
- fn sign_closing_transaction(&self, closing_tx: &Transaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
- if closing_tx.input.len() != 1 { return Err(()); }
- if closing_tx.input[0].witness.len() != 0 { return Err(()); }
- if closing_tx.output.len() > 2 { return Err(()); }
-
+ fn sign_closing_transaction(&self, closing_tx: &ClosingTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
-
- let sighash = hash_to_message!(&bip143::SigHashCache::new(closing_tx)
- .signature_hash(0, &channel_funding_redeemscript, self.channel_value_satoshis, SigHashType::All)[..]);
- Ok(secp_ctx.sign(&sighash, &self.funding_key))
+ Ok(closing_tx.trust().sign(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx))
}
fn sign_channel_announcement(&self, msg: &UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
use ln::{PaymentHash, PaymentPreimage};
use ln::msgs::DecodeError;
use util::ser::{Readable, Writeable, Writer};
-use util::byte_utils;
+use util::{byte_utils, transaction_utils};
use bitcoin::hash_types::WPubkeyHash;
use bitcoin::secp256k1::key::{SecretKey, PublicKey};
res
}
+/// Build a closing 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 {
+ previous_output: funding_outpoint,
+ script_sig: Script::new(),
+ sequence: 0xffffffff,
+ witness: Vec::new(),
+ });
+ ins
+ };
+
+ let mut txouts: Vec<(TxOut, ())> = Vec::new();
+
+ if to_counterparty_value_sat > 0 {
+ txouts.push((TxOut {
+ script_pubkey: to_counterparty_script,
+ value: to_counterparty_value_sat
+ }, ()));
+ }
+
+ if to_holder_value_sat > 0 {
+ txouts.push((TxOut {
+ script_pubkey: to_holder_script,
+ value: to_holder_value_sat
+ }, ()));
+ }
+
+ transaction_utils::sort_outputs(&mut txouts, |_, _| { cmp::Ordering::Equal }); // Ordering doesnt matter if they used our pubkey...
+
+ let mut outputs: Vec<TxOut> = Vec::new();
+ for out in txouts.drain(..) {
+ outputs.push(out.0);
+ }
+
+ Transaction {
+ version: 2,
+ lock_time: 0,
+ input: txins,
+ output: outputs,
+ }
+}
+
/// Implements the per-commitment secret storage scheme from
/// [BOLT 3](https://github.com/lightningnetwork/lightning-rfc/blob/dcbf8583976df087c79c3ce0b535311212e6812d/03-transactions.md#efficient-per-commitment-secret-storage).
///
}
}
-/// 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.
///
/// 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 }
}
// licenses.
use bitcoin::blockdata::script::{Script,Builder};
-use bitcoin::blockdata::transaction::{TxIn, TxOut, Transaction, SigHashType};
+use bitcoin::blockdata::transaction::{Transaction, SigHashType};
use bitcoin::util::bip143;
use bitcoin::consensus::encode;
use ln::msgs::{DecodeError, OptionalField, DataLossProtect};
use ln::script::ShutdownScript;
use ln::channelmanager::{PendingHTLCStatus, HTLCSource, HTLCFailReason, HTLCFailureMsg, PendingHTLCInfo, RAACommitmentOrder, BREAKDOWN_TIMEOUT, MIN_CLTV_EXPIRY_DELTA, MAX_LOCAL_BREAKDOWN_TIMEOUT};
-use ln::chan_utils::{CounterpartyCommitmentSecrets, TxCreationKeys, HTLCOutputInCommitment, HTLC_SUCCESS_TX_WEIGHT, HTLC_TIMEOUT_TX_WEIGHT, make_funding_redeemscript, ChannelPublicKeys, CommitmentTransaction, HolderCommitmentTransaction, ChannelTransactionParameters, CounterpartyChannelTransactionParameters, MAX_HTLCS, get_commitment_transaction_number_obscure_factor};
+use ln::chan_utils::{CounterpartyCommitmentSecrets, TxCreationKeys, HTLCOutputInCommitment, HTLC_SUCCESS_TX_WEIGHT, HTLC_TIMEOUT_TX_WEIGHT, make_funding_redeemscript, ChannelPublicKeys, CommitmentTransaction, HolderCommitmentTransaction, ChannelTransactionParameters, CounterpartyChannelTransactionParameters, MAX_HTLCS, get_commitment_transaction_number_obscure_factor, ClosingTransaction};
use ln::chan_utils;
use chain::BestBlock;
use chain::chaininterface::{FeeEstimator,ConfirmationTarget};
use chain::channelmonitor::{ChannelMonitor, ChannelMonitorUpdate, ChannelMonitorUpdateStep, HTLC_FAIL_BACK_BUFFER};
use chain::transaction::{OutPoint, TransactionData};
use chain::keysinterface::{Sign, KeysInterface};
-use util::transaction_utils;
use util::ser::{Readable, ReadableArgs, Writeable, Writer, VecWriter};
use util::logger::Logger;
use util::errors::APIError;
}
#[inline]
- fn build_closing_transaction(&self, proposed_total_fee_satoshis: u64, skip_remote_output: bool) -> (Transaction, u64) {
- let txins = {
- let mut ins: Vec<TxIn> = Vec::new();
- ins.push(TxIn {
- previous_output: self.funding_outpoint().into_bitcoin_outpoint(),
- script_sig: Script::new(),
- sequence: 0xffffffff,
- witness: Vec::new(),
- });
- ins
- };
-
+ fn build_closing_transaction(&self, proposed_total_fee_satoshis: u64, skip_remote_output: bool) -> (ClosingTransaction, u64) {
assert!(self.pending_inbound_htlcs.is_empty());
assert!(self.pending_outbound_htlcs.is_empty());
assert!(self.pending_update_fee.is_none());
- let mut txouts: Vec<(TxOut, ())> = Vec::new();
let mut total_fee_satoshis = proposed_total_fee_satoshis;
- let value_to_self: i64 = (self.value_to_self_msat as i64) / 1000 - if self.is_outbound() { total_fee_satoshis as i64 } else { 0 };
- let value_to_remote: i64 = ((self.channel_value_satoshis * 1000 - self.value_to_self_msat) as i64 / 1000) - if self.is_outbound() { 0 } else { total_fee_satoshis as i64 };
+ let mut value_to_holder: i64 = (self.value_to_self_msat as i64) / 1000 - if self.is_outbound() { total_fee_satoshis as i64 } else { 0 };
+ let mut value_to_counterparty: i64 = ((self.channel_value_satoshis * 1000 - self.value_to_self_msat) as i64 / 1000) - if self.is_outbound() { 0 } else { total_fee_satoshis as i64 };
- if value_to_self < 0 {
+ if value_to_holder < 0 {
assert!(self.is_outbound());
- total_fee_satoshis += (-value_to_self) as u64;
- } else if value_to_remote < 0 {
+ total_fee_satoshis += (-value_to_holder) as u64;
+ } else if value_to_counterparty < 0 {
assert!(!self.is_outbound());
- total_fee_satoshis += (-value_to_remote) as u64;
+ total_fee_satoshis += (-value_to_counterparty) as u64;
}
- if !skip_remote_output && value_to_remote as u64 > self.holder_dust_limit_satoshis {
- txouts.push((TxOut {
- script_pubkey: self.counterparty_shutdown_scriptpubkey.clone().unwrap(),
- value: value_to_remote as u64
- }, ()));
+ if skip_remote_output || value_to_counterparty as u64 <= self.holder_dust_limit_satoshis {
+ value_to_counterparty = 0;
}
- assert!(self.shutdown_scriptpubkey.is_some());
- if value_to_self as u64 > self.holder_dust_limit_satoshis {
- txouts.push((TxOut {
- script_pubkey: self.get_closing_scriptpubkey(),
- value: value_to_self as u64
- }, ()));
+ if value_to_holder as u64 <= self.holder_dust_limit_satoshis {
+ value_to_holder = 0;
}
- transaction_utils::sort_outputs(&mut txouts, |_, _| { cmp::Ordering::Equal }); // Ordering doesnt matter if they used our pubkey...
-
- let mut outputs: Vec<TxOut> = Vec::new();
- for out in txouts.drain(..) {
- outputs.push(out.0);
- }
+ assert!(self.shutdown_scriptpubkey.is_some());
+ let holder_shutdown_script = self.get_closing_scriptpubkey();
+ let counterparty_shutdown_script = self.counterparty_shutdown_scriptpubkey.clone().unwrap();
+ let funding_outpoint = self.funding_outpoint().into_bitcoin_outpoint();
- (Transaction {
- version: 2,
- lock_time: 0,
- input: txins,
- output: outputs,
- }, total_fee_satoshis)
+ let closing_transaction = ClosingTransaction::new(value_to_holder as u64, value_to_counterparty as u64, holder_shutdown_script, counterparty_shutdown_script, funding_outpoint);
+ (closing_transaction, total_fee_satoshis)
}
fn funding_outpoint(&self) -> OutPoint {
Ok((shutdown, monitor_update, dropped_outbound_htlcs))
}
- fn build_signed_closing_transaction(&self, tx: &mut Transaction, counterparty_sig: &Signature, sig: &Signature) {
- if tx.input.len() != 1 { panic!("Tried to sign closing transaction that had input count != 1!"); }
- if tx.input[0].witness.len() != 0 { panic!("Tried to re-sign closing transaction"); }
- if tx.output.len() > 2 { panic!("Tried to sign bogus closing transaction"); }
+ fn build_signed_closing_transaction(&self, closing_tx: &ClosingTransaction, counterparty_sig: &Signature, sig: &Signature) -> Transaction {
+ let mut tx = closing_tx.trust().built_transaction().clone();
tx.input[0].witness.push(Vec::new()); // First is the multisig dummy
tx.input[0].witness[2].push(SigHashType::All as u8);
tx.input[0].witness.push(self.get_funding_redeemscript().into_bytes());
+ tx
}
pub fn closing_signed<F: Deref>(&mut self, fee_estimator: &F, msg: &msgs::ClosingSigned) -> Result<(Option<msgs::ClosingSigned>, Option<Transaction>), ChannelError>
if used_total_fee != msg.fee_satoshis {
return Err(ChannelError::Close(format!("Remote sent us a closing_signed with a fee other than the value they can claim. Fee in message: {}. Actual closing tx fee: {}", msg.fee_satoshis, used_total_fee)));
}
- let mut sighash = hash_to_message!(&bip143::SigHashCache::new(&closing_tx).signature_hash(0, &funding_redeemscript, self.channel_value_satoshis, SigHashType::All)[..]);
+ let sighash = closing_tx.trust().get_sighash_all(&funding_redeemscript, self.channel_value_satoshis);
match self.secp_ctx.verify(&sighash, &msg.signature, &self.get_counterparty_pubkeys().funding_pubkey) {
Ok(_) => {},
// The remote end may have decided to revoke their output due to inconsistent dust
// limits, so check for that case by re-checking the signature here.
closing_tx = self.build_closing_transaction(msg.fee_satoshis, true).0;
- sighash = hash_to_message!(&bip143::SigHashCache::new(&closing_tx).signature_hash(0, &funding_redeemscript, self.channel_value_satoshis, SigHashType::All)[..]);
+ let sighash = closing_tx.trust().get_sighash_all(&funding_redeemscript, self.channel_value_satoshis);
secp_check!(self.secp_ctx.verify(&sighash, &msg.signature, self.counterparty_funding_pubkey()), "Invalid closing tx signature from peer".to_owned());
},
};
assert!(self.shutdown_scriptpubkey.is_some());
if let Some((last_fee, sig)) = self.last_sent_closing_fee {
if last_fee == msg.fee_satoshis {
- self.build_signed_closing_transaction(&mut closing_tx, &msg.signature, &sig);
+ let tx = self.build_signed_closing_transaction(&mut closing_tx, &msg.signature, &sig);
self.channel_state = ChannelState::ShutdownComplete as u32;
self.update_time_counter += 1;
- return Ok((None, Some(closing_tx)));
+ return Ok((None, Some(tx)));
}
}
macro_rules! propose_fee {
($new_fee: expr) => {
- let (mut tx, used_fee) = if $new_fee == msg.fee_satoshis {
+ let (closing_tx, used_fee) = if $new_fee == msg.fee_satoshis {
(closing_tx, $new_fee)
} else {
self.build_closing_transaction($new_fee, false)
};
let sig = self.holder_signer
- .sign_closing_transaction(&tx, &self.secp_ctx)
+ .sign_closing_transaction(&closing_tx, &self.secp_ctx)
.map_err(|_| ChannelError::Close("External signer refused to sign closing transaction".to_owned()))?;
let signed_tx = if $new_fee == msg.fee_satoshis {
self.channel_state = ChannelState::ShutdownComplete as u32;
self.update_time_counter += 1;
- self.build_signed_closing_transaction(&mut tx, &msg.signature, &sig);
+ let tx = self.build_signed_closing_transaction(&closing_tx, &msg.signature, &sig);
Some(tx)
} else { None };
// You may not use this file except in accordance with one or both of these
// licenses.
-use ln::chan_utils::{HTLCOutputInCommitment, ChannelPublicKeys, HolderCommitmentTransaction, CommitmentTransaction, ChannelTransactionParameters, TrustedCommitmentTransaction};
+use ln::chan_utils::{HTLCOutputInCommitment, ChannelPublicKeys, HolderCommitmentTransaction, CommitmentTransaction, ChannelTransactionParameters, TrustedCommitmentTransaction, ClosingTransaction};
use ln::{chan_utils, msgs};
use chain::keysinterface::{Sign, InMemorySigner, BaseSign};
Ok(self.inner.sign_counterparty_htlc_transaction(htlc_tx, input, amount, per_commitment_point, htlc, secp_ctx).unwrap())
}
- fn sign_closing_transaction(&self, closing_tx: &Transaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
+ fn sign_closing_transaction(&self, closing_tx: &ClosingTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
+ closing_tx.verify(self.inner.funding_outpoint().into_bitcoin_outpoint())
+ .expect("derived different closing transaction");
Ok(self.inner.sign_closing_transaction(closing_tx, secp_ctx).unwrap())
}
projects / rust-lightning / commitdiff