use bitcoin::consensus::encode::{self, Decodable, Encodable};
use bitcoin::util::bip143;
-use bitcoin_hashes::{Hash, HashEngine};
-use bitcoin_hashes::sha256::Hash as Sha256;
-use bitcoin_hashes::ripemd160::Hash as Ripemd160;
-use bitcoin_hashes::hash160::Hash as Hash160;
-use bitcoin_hashes::sha256d::Hash as Sha256dHash;
+use bitcoin::hashes::{Hash, HashEngine};
+use bitcoin::hashes::sha256::Hash as Sha256;
+use bitcoin::hashes::ripemd160::Hash as Ripemd160;
+use bitcoin::hash_types::{Txid, PubkeyHash};
use ln::channelmanager::{PaymentHash, PaymentPreimage};
use ln::msgs::DecodeError;
use util::ser::{Readable, Writeable, Writer, WriterWriteAdaptor};
use util::byte_utils;
-use secp256k1::key::{SecretKey, PublicKey};
-use secp256k1::{Secp256k1, Signature};
-use secp256k1;
+use bitcoin::secp256k1::key::{SecretKey, PublicKey};
+use bitcoin::secp256k1::{Secp256k1, Signature};
+use bitcoin::secp256k1;
+
+use std::{cmp, mem};
+
+const MAX_ALLOC_SIZE: usize = 64*1024;
pub(super) const HTLC_SUCCESS_TX_WEIGHT: u64 = 703;
pub(super) const HTLC_TIMEOUT_TX_WEIGHT: u64 = 663;
pub(crate) b_htlc_key: PublicKey,
/// A's Payment Key (which isn't allowed to be spent from for some delay)
pub(crate) a_delayed_payment_key: PublicKey,
- /// B's Payment Key
- pub(crate) b_payment_key: PublicKey,
}
impl_writeable!(TxCreationKeys, 33*6,
- { per_commitment_point, revocation_key, a_htlc_key, b_htlc_key, a_delayed_payment_key, b_payment_key });
+ { per_commitment_point, revocation_key, a_htlc_key, b_htlc_key, a_delayed_payment_key });
/// One counterparty's public keys which do not change over the life of a channel.
#[derive(Clone, PartialEq)]
/// a commitment transaction so that their counterparty can claim all available funds if they
/// broadcast an old state.
pub revocation_basepoint: PublicKey,
- /// The base point which is used (with derive_public_key) to derive a per-commitment payment
- /// public key which receives immediately-spendable non-HTLC-encumbered funds.
- pub payment_basepoint: PublicKey,
+ /// The public key which receives our immediately spendable primary channel balance in
+ /// remote-broadcasted commitment transactions. This key is static across every commitment
+ /// transaction.
+ pub payment_point: PublicKey,
/// The base point which is used (with derive_public_key) to derive a per-commitment payment
/// public key which receives non-HTLC-encumbered funds which are only available for spending
/// after some delay (or can be claimed via the revocation path).
impl_writeable!(ChannelPublicKeys, 33*5, {
funding_pubkey,
revocation_basepoint,
- payment_basepoint,
+ payment_point,
delayed_payment_basepoint,
htlc_basepoint
});
impl TxCreationKeys {
- pub(crate) fn new<T: secp256k1::Signing + secp256k1::Verification>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, a_delayed_payment_base: &PublicKey, a_htlc_base: &PublicKey, b_revocation_base: &PublicKey, b_payment_base: &PublicKey, b_htlc_base: &PublicKey) -> Result<TxCreationKeys, secp256k1::Error> {
+ pub(crate) fn new<T: secp256k1::Signing + secp256k1::Verification>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, a_delayed_payment_base: &PublicKey, a_htlc_base: &PublicKey, b_revocation_base: &PublicKey, b_htlc_base: &PublicKey) -> Result<TxCreationKeys, secp256k1::Error> {
Ok(TxCreationKeys {
per_commitment_point: per_commitment_point.clone(),
revocation_key: derive_public_revocation_key(&secp_ctx, &per_commitment_point, &b_revocation_base)?,
a_htlc_key: derive_public_key(&secp_ctx, &per_commitment_point, &a_htlc_base)?,
b_htlc_key: derive_public_key(&secp_ctx, &per_commitment_point, &b_htlc_base)?,
a_delayed_payment_key: derive_public_key(&secp_ctx, &per_commitment_point, &a_delayed_payment_base)?,
- b_payment_key: derive_public_key(&secp_ctx, &per_commitment_point, &b_payment_base)?,
})
}
}
});
#[inline]
-pub(super) fn get_htlc_redeemscript_with_explicit_keys(htlc: &HTLCOutputInCommitment, a_htlc_key: &PublicKey, b_htlc_key: &PublicKey, revocation_key: &PublicKey) -> Script {
+pub(crate) fn get_htlc_redeemscript_with_explicit_keys(htlc: &HTLCOutputInCommitment, a_htlc_key: &PublicKey, b_htlc_key: &PublicKey, revocation_key: &PublicKey) -> Script {
let payment_hash160 = Ripemd160::hash(&htlc.payment_hash.0[..]).into_inner();
if htlc.offered {
Builder::new().push_opcode(opcodes::all::OP_DUP)
.push_opcode(opcodes::all::OP_HASH160)
- .push_slice(&Hash160::hash(&revocation_key.serialize())[..])
+ .push_slice(&PubkeyHash::hash(&revocation_key.serialize())[..])
.push_opcode(opcodes::all::OP_EQUAL)
.push_opcode(opcodes::all::OP_IF)
.push_opcode(opcodes::all::OP_CHECKSIG)
} else {
Builder::new().push_opcode(opcodes::all::OP_DUP)
.push_opcode(opcodes::all::OP_HASH160)
- .push_slice(&Hash160::hash(&revocation_key.serialize())[..])
+ .push_slice(&PubkeyHash::hash(&revocation_key.serialize())[..])
.push_opcode(opcodes::all::OP_EQUAL)
.push_opcode(opcodes::all::OP_IF)
.push_opcode(opcodes::all::OP_CHECKSIG)
}
/// panics if htlc.transaction_output_index.is_none()!
-pub fn build_htlc_transaction(prev_hash: &Sha256dHash, feerate_per_kw: u64, to_self_delay: u16, htlc: &HTLCOutputInCommitment, a_delayed_payment_key: &PublicKey, revocation_key: &PublicKey) -> Transaction {
+pub fn build_htlc_transaction(prev_hash: &Txid, feerate_per_kw: u64, to_self_delay: u16, htlc: &HTLCOutputInCommitment, a_delayed_payment_key: &PublicKey, revocation_key: &PublicKey) -> Transaction {
let mut txins: Vec<TxIn> = Vec::new();
txins.push(TxIn {
previous_output: OutPoint {
}
}
-/// Signs a transaction created by build_htlc_transaction. If the transaction is an
-/// HTLC-Success transaction (ie htlc.offered is false), preimage must be set!
-pub(crate) fn sign_htlc_transaction<T: secp256k1::Signing>(tx: &mut Transaction, their_sig: &Signature, preimage: &Option<PaymentPreimage>, htlc: &HTLCOutputInCommitment, a_htlc_key: &PublicKey, b_htlc_key: &PublicKey, revocation_key: &PublicKey, per_commitment_point: &PublicKey, htlc_base_key: &SecretKey, secp_ctx: &Secp256k1<T>) -> Result<(Signature, Script), ()> {
- if tx.input.len() != 1 { return Err(()); }
- if tx.input[0].witness.len() != 0 { return Err(()); }
-
- let htlc_redeemscript = get_htlc_redeemscript_with_explicit_keys(&htlc, a_htlc_key, b_htlc_key, revocation_key);
-
- let our_htlc_key = derive_private_key(secp_ctx, per_commitment_point, htlc_base_key).map_err(|_| ())?;
- let sighash = hash_to_message!(&bip143::SighashComponents::new(&tx).sighash_all(&tx.input[0], &htlc_redeemscript, htlc.amount_msat / 1000)[..]);
- let local_tx = PublicKey::from_secret_key(&secp_ctx, &our_htlc_key) == *a_htlc_key;
- let our_sig = secp_ctx.sign(&sighash, &our_htlc_key);
-
- tx.input[0].witness.push(Vec::new()); // First is the multisig dummy
-
- if local_tx { // b, then a
- tx.input[0].witness.push(their_sig.serialize_der().to_vec());
- tx.input[0].witness.push(our_sig.serialize_der().to_vec());
- } else {
- tx.input[0].witness.push(our_sig.serialize_der().to_vec());
- tx.input[0].witness.push(their_sig.serialize_der().to_vec());
- }
- tx.input[0].witness[1].push(SigHashType::All as u8);
- tx.input[0].witness[2].push(SigHashType::All as u8);
-
- if htlc.offered {
- tx.input[0].witness.push(Vec::new());
- assert!(preimage.is_none());
- } else {
- tx.input[0].witness.push(preimage.unwrap().0.to_vec());
- }
-
- tx.input[0].witness.push(htlc_redeemscript.as_bytes().to_vec());
-
- Ok((our_sig, htlc_redeemscript))
-}
-
#[derive(Clone)]
/// We use this to track local commitment transactions and put off signing them until we are ready
/// to broadcast. Eventually this will require a signer which is possibly external, but for now we
/// just pass in the SecretKeys required.
-pub(crate) struct LocalCommitmentTransaction {
- tx: Transaction
+pub struct LocalCommitmentTransaction {
+ // TODO: We should migrate away from providing the transaction, instead providing enough to
+ // allow the ChannelKeys to construct it from scratch. Luckily we already have HTLC data here,
+ // so we're probably most of the way there.
+ /// The commitment transaction itself, in unsigned form.
+ pub unsigned_tx: Transaction,
+ /// Our counterparty's signature for the transaction, above.
+ pub their_sig: Signature,
+ // Which order the signatures should go in when constructing the final commitment tx witness.
+ // The user should be able to reconstruc this themselves, so we don't bother to expose it.
+ our_sig_first: bool,
+ /// The key derivation parameters for this commitment transaction
+ pub local_keys: TxCreationKeys,
+ /// The feerate paid per 1000-weight-unit in this commitment transaction. This value is
+ /// controlled by the channel initiator.
+ pub feerate_per_kw: u64,
+ /// The HTLCs and remote htlc signatures which were included in this commitment transaction.
+ ///
+ /// Note that this includes all HTLCs, including ones which were considered dust and not
+ /// actually included in the transaction as it appears on-chain, but who's value is burned as
+ /// fees and not included in the to_local or to_remote outputs.
+ ///
+ /// The remote HTLC signatures in the second element will always be set for non-dust HTLCs, ie
+ /// those for which transaction_output_index.is_some().
+ pub per_htlc: Vec<(HTLCOutputInCommitment, Option<Signature>)>,
}
impl LocalCommitmentTransaction {
#[cfg(test)]
pub fn dummy() -> Self {
- Self { tx: Transaction {
- version: 2,
- input: Vec::new(),
- output: Vec::new(),
- lock_time: 0,
- } }
+ let dummy_input = TxIn {
+ previous_output: OutPoint {
+ txid: Default::default(),
+ vout: 0,
+ },
+ script_sig: Default::default(),
+ sequence: 0,
+ witness: vec![]
+ };
+ let dummy_key = PublicKey::from_secret_key(&Secp256k1::new(), &SecretKey::from_slice(&[42; 32]).unwrap());
+ let dummy_sig = Secp256k1::new().sign(&secp256k1::Message::from_slice(&[42; 32]).unwrap(), &SecretKey::from_slice(&[42; 32]).unwrap());
+ Self {
+ unsigned_tx: Transaction {
+ version: 2,
+ input: vec![dummy_input],
+ output: Vec::new(),
+ lock_time: 0,
+ },
+ their_sig: dummy_sig,
+ our_sig_first: false,
+ local_keys: TxCreationKeys {
+ per_commitment_point: dummy_key.clone(),
+ revocation_key: dummy_key.clone(),
+ a_htlc_key: dummy_key.clone(),
+ b_htlc_key: dummy_key.clone(),
+ a_delayed_payment_key: dummy_key.clone(),
+ },
+ feerate_per_kw: 0,
+ per_htlc: Vec::new()
+ }
}
- pub fn new_missing_local_sig(mut tx: Transaction, their_sig: &Signature, our_funding_key: &PublicKey, their_funding_key: &PublicKey) -> LocalCommitmentTransaction {
- if tx.input.len() != 1 { panic!("Tried to store a commitment transaction that had input count != 1!"); }
- if tx.input[0].witness.len() != 0 { panic!("Tried to store a signed commitment transaction?"); }
-
- tx.input[0].witness.push(Vec::new()); // First is the multisig dummy
-
- if our_funding_key.serialize()[..] < their_funding_key.serialize()[..] {
- tx.input[0].witness.push(Vec::new());
- tx.input[0].witness.push(their_sig.serialize_der().to_vec());
- tx.input[0].witness[2].push(SigHashType::All as u8);
- } else {
- tx.input[0].witness.push(their_sig.serialize_der().to_vec());
- tx.input[0].witness[1].push(SigHashType::All as u8);
- tx.input[0].witness.push(Vec::new());
+ /// Generate a new LocalCommitmentTransaction based on a raw commitment transaction,
+ /// remote signature and both parties keys
+ pub(crate) fn new_missing_local_sig(unsigned_tx: Transaction, their_sig: Signature, our_funding_key: &PublicKey, their_funding_key: &PublicKey, local_keys: TxCreationKeys, feerate_per_kw: u64, htlc_data: Vec<(HTLCOutputInCommitment, Option<Signature>)>) -> LocalCommitmentTransaction {
+ if unsigned_tx.input.len() != 1 { panic!("Tried to store a commitment transaction that had input count != 1!"); }
+ if unsigned_tx.input[0].witness.len() != 0 { panic!("Tried to store a signed commitment transaction?"); }
+
+ Self {
+ unsigned_tx,
+ their_sig,
+ our_sig_first: our_funding_key.serialize()[..] < their_funding_key.serialize()[..],
+ local_keys,
+ feerate_per_kw,
+ per_htlc: htlc_data,
}
+ }
- Self { tx }
+ /// Get the txid of the local commitment transaction contained in this
+ /// LocalCommitmentTransaction
+ pub fn txid(&self) -> Txid {
+ self.unsigned_tx.txid()
}
- pub fn txid(&self) -> Sha256dHash {
- self.tx.txid()
+ /// Gets our signature for the contained commitment transaction given our funding private key.
+ ///
+ /// Funding key is your key included in the 2-2 funding_outpoint lock. Should be provided
+ /// by your ChannelKeys.
+ /// Funding redeemscript is script locking funding_outpoint. This is the mutlsig script
+ /// between your own funding key and your counterparty's. Currently, this is provided in
+ /// ChannelKeys::sign_local_commitment() calls directly.
+ /// Channel value is amount locked in funding_outpoint.
+ pub fn get_local_sig<T: secp256k1::Signing>(&self, funding_key: &SecretKey, funding_redeemscript: &Script, channel_value_satoshis: u64, secp_ctx: &Secp256k1<T>) -> Signature {
+ let sighash = hash_to_message!(&bip143::SighashComponents::new(&self.unsigned_tx)
+ .sighash_all(&self.unsigned_tx.input[0], funding_redeemscript, channel_value_satoshis)[..]);
+ secp_ctx.sign(&sighash, funding_key)
}
- pub fn has_local_sig(&self) -> bool {
- if self.tx.input.len() != 1 { panic!("Commitment transactions must have input count == 1!"); }
- if self.tx.input[0].witness.len() == 4 {
- assert!(!self.tx.input[0].witness[1].is_empty());
- assert!(!self.tx.input[0].witness[2].is_empty());
- true
+ pub(crate) fn add_local_sig(&self, funding_redeemscript: &Script, our_sig: Signature) -> Transaction {
+ let mut tx = self.unsigned_tx.clone();
+ // First push the multisig dummy, note that due to BIP147 (NULLDUMMY) it must be a zero-length element.
+ tx.input[0].witness.push(Vec::new());
+
+ if self.our_sig_first {
+ tx.input[0].witness.push(our_sig.serialize_der().to_vec());
+ tx.input[0].witness.push(self.their_sig.serialize_der().to_vec());
} else {
- assert_eq!(self.tx.input[0].witness.len(), 3);
- assert!(self.tx.input[0].witness[0].is_empty());
- assert!(self.tx.input[0].witness[1].is_empty() || self.tx.input[0].witness[2].is_empty());
- false
+ tx.input[0].witness.push(self.their_sig.serialize_der().to_vec());
+ tx.input[0].witness.push(our_sig.serialize_der().to_vec());
}
+ tx.input[0].witness[1].push(SigHashType::All as u8);
+ tx.input[0].witness[2].push(SigHashType::All as u8);
+
+ tx.input[0].witness.push(funding_redeemscript.as_bytes().to_vec());
+ tx
}
- pub fn add_local_sig<T: secp256k1::Signing>(&mut self, funding_key: &SecretKey, funding_redeemscript: &Script, channel_value_satoshis: u64, secp_ctx: &Secp256k1<T>) {
- if self.has_local_sig() { return; }
- let sighash = hash_to_message!(&bip143::SighashComponents::new(&self.tx)
- .sighash_all(&self.tx.input[0], funding_redeemscript, channel_value_satoshis)[..]);
- let our_sig = secp_ctx.sign(&sighash, funding_key);
+ /// Get a signature for each HTLC which was included in the commitment transaction (ie for
+ /// which HTLCOutputInCommitment::transaction_output_index.is_some()).
+ ///
+ /// The returned Vec has one entry for each HTLC, and in the same order. For HTLCs which were
+ /// considered dust and not included, a None entry exists, for all others a signature is
+ /// included.
+ pub fn get_htlc_sigs<T: secp256k1::Signing + secp256k1::Verification>(&self, htlc_base_key: &SecretKey, local_csv: u16, secp_ctx: &Secp256k1<T>) -> Result<Vec<Option<Signature>>, ()> {
+ let txid = self.txid();
+ let mut ret = Vec::with_capacity(self.per_htlc.len());
+ let our_htlc_key = derive_private_key(secp_ctx, &self.local_keys.per_commitment_point, htlc_base_key).map_err(|_| ())?;
+
+ for this_htlc in self.per_htlc.iter() {
+ if this_htlc.0.transaction_output_index.is_some() {
+ let htlc_tx = build_htlc_transaction(&txid, self.feerate_per_kw, local_csv, &this_htlc.0, &self.local_keys.a_delayed_payment_key, &self.local_keys.revocation_key);
+
+ let htlc_redeemscript = get_htlc_redeemscript_with_explicit_keys(&this_htlc.0, &self.local_keys.a_htlc_key, &self.local_keys.b_htlc_key, &self.local_keys.revocation_key);
+
+ let sighash = hash_to_message!(&bip143::SighashComponents::new(&htlc_tx).sighash_all(&htlc_tx.input[0], &htlc_redeemscript, this_htlc.0.amount_msat / 1000)[..]);
+ ret.push(Some(secp_ctx.sign(&sighash, &our_htlc_key)));
+ } else {
+ ret.push(None);
+ }
+ }
+ Ok(ret)
+ }
- if self.tx.input[0].witness[1].is_empty() {
- self.tx.input[0].witness[1] = our_sig.serialize_der().to_vec();
- self.tx.input[0].witness[1].push(SigHashType::All as u8);
+ /// Gets a signed HTLC transaction given a preimage (for !htlc.offered) and the local HTLC transaction signature.
+ pub(crate) fn get_signed_htlc_tx(&self, htlc_index: usize, signature: &Signature, preimage: &Option<PaymentPreimage>, local_csv: u16) -> Transaction {
+ let txid = self.txid();
+ let this_htlc = &self.per_htlc[htlc_index];
+ assert!(this_htlc.0.transaction_output_index.is_some());
+ // if we don't have preimage for an HTLC-Success, we can't generate an HTLC transaction.
+ if !this_htlc.0.offered && preimage.is_none() { unreachable!(); }
+ // Further, we should never be provided the preimage for an HTLC-Timeout transaction.
+ if this_htlc.0.offered && preimage.is_some() { unreachable!(); }
+
+ let mut htlc_tx = build_htlc_transaction(&txid, self.feerate_per_kw, local_csv, &this_htlc.0, &self.local_keys.a_delayed_payment_key, &self.local_keys.revocation_key);
+ // Channel should have checked that we have a remote signature for this HTLC at
+ // creation, and we should have a sensible htlc transaction:
+ assert!(this_htlc.1.is_some());
+
+ let htlc_redeemscript = get_htlc_redeemscript_with_explicit_keys(&this_htlc.0, &self.local_keys.a_htlc_key, &self.local_keys.b_htlc_key, &self.local_keys.revocation_key);
+
+ // First push the multisig dummy, note that due to BIP147 (NULLDUMMY) it must be a zero-length element.
+ htlc_tx.input[0].witness.push(Vec::new());
+
+ htlc_tx.input[0].witness.push(this_htlc.1.unwrap().serialize_der().to_vec());
+ htlc_tx.input[0].witness.push(signature.serialize_der().to_vec());
+ htlc_tx.input[0].witness[1].push(SigHashType::All as u8);
+ htlc_tx.input[0].witness[2].push(SigHashType::All as u8);
+
+ if this_htlc.0.offered {
+ // Due to BIP146 (MINIMALIF) this must be a zero-length element to relay.
+ htlc_tx.input[0].witness.push(Vec::new());
} else {
- self.tx.input[0].witness[2] = our_sig.serialize_der().to_vec();
- self.tx.input[0].witness[2].push(SigHashType::All as u8);
+ htlc_tx.input[0].witness.push(preimage.unwrap().0.to_vec());
}
- self.tx.input[0].witness.push(funding_redeemscript.as_bytes().to_vec());
- }
-
- pub fn without_valid_witness(&self) -> &Transaction { &self.tx }
- pub fn with_valid_witness(&self) -> &Transaction {
- assert!(self.has_local_sig());
- &self.tx
+ htlc_tx.input[0].witness.push(htlc_redeemscript.as_bytes().to_vec());
+ htlc_tx
}
}
impl PartialEq for LocalCommitmentTransaction {
}
impl Writeable for LocalCommitmentTransaction {
fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
- if let Err(e) = self.tx.consensus_encode(&mut WriterWriteAdaptor(writer)) {
+ if let Err(e) = self.unsigned_tx.consensus_encode(&mut WriterWriteAdaptor(writer)) {
match e {
encode::Error::Io(e) => return Err(e),
_ => panic!("local tx must have been well-formed!"),
}
}
+ self.their_sig.write(writer)?;
+ self.our_sig_first.write(writer)?;
+ self.local_keys.write(writer)?;
+ self.feerate_per_kw.write(writer)?;
+ writer.write_all(&byte_utils::be64_to_array(self.per_htlc.len() as u64))?;
+ for &(ref htlc, ref sig) in self.per_htlc.iter() {
+ htlc.write(writer)?;
+ sig.write(writer)?;
+ }
Ok(())
}
}
impl Readable for LocalCommitmentTransaction {
fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
- let tx = match Transaction::consensus_decode(reader.by_ref()) {
+ let unsigned_tx = match Transaction::consensus_decode(reader.by_ref()) {
Ok(tx) => tx,
Err(e) => match e {
encode::Error::Io(ioe) => return Err(DecodeError::Io(ioe)),
_ => return Err(DecodeError::InvalidValue),
},
};
+ let their_sig = Readable::read(reader)?;
+ let our_sig_first = Readable::read(reader)?;
+ let local_keys = Readable::read(reader)?;
+ let feerate_per_kw = Readable::read(reader)?;
+ let htlcs_count: u64 = Readable::read(reader)?;
+ let mut per_htlc = Vec::with_capacity(cmp::min(htlcs_count as usize, MAX_ALLOC_SIZE / mem::size_of::<(HTLCOutputInCommitment, Option<Signature>)>()));
+ for _ in 0..htlcs_count {
+ let htlc: HTLCOutputInCommitment = Readable::read(reader)?;
+ let sigs = Readable::read(reader)?;
+ per_htlc.push((htlc, sigs));
+ }
- if tx.input.len() != 1 {
+ if unsigned_tx.input.len() != 1 {
// Ensure tx didn't hit the 0-input ambiguity case.
return Err(DecodeError::InvalidValue);
}
- Ok(Self { tx })
+ Ok(Self {
+ unsigned_tx,
+ their_sig,
+ our_sig_first,
+ local_keys,
+ feerate_per_kw,
+ per_htlc,
+ })
}
}
projects / rust-lightning / blobdiff