// licenses.
//! Various utilities for building scripts and deriving keys related to channels. These are
-//! largely of interest for those implementing chain::keysinterface::ChannelKeys message signing
-//! by hand.
+//! largely of interest for those implementing chain::keysinterface::Sign message signing by hand.
use bitcoin::blockdata::script::{Script,Builder};
use bitcoin::blockdata::opcodes;
use bitcoin::blockdata::transaction::{TxIn,TxOut,OutPoint,Transaction, SigHashType};
-use bitcoin::consensus::encode::{Decodable, Encodable};
-use bitcoin::consensus::encode;
use bitcoin::util::bip143;
use bitcoin::hashes::{Hash, HashEngine};
use bitcoin::hashes::ripemd160::Hash as Ripemd160;
use bitcoin::hash_types::{Txid, PubkeyHash};
-use ln::channelmanager::{PaymentHash, PaymentPreimage};
+use ln::{PaymentHash, PaymentPreimage};
use ln::msgs::DecodeError;
-use util::ser::{Readable, Writeable, Writer, WriterWriteAdaptor};
+use util::ser::{Readable, Writeable, Writer};
use util::byte_utils;
+use bitcoin::hash_types::WPubkeyHash;
use bitcoin::secp256k1::key::{SecretKey, PublicKey};
-use bitcoin::secp256k1::{Secp256k1, Signature};
+use bitcoin::secp256k1::{Secp256k1, Signature, Message};
use bitcoin::secp256k1::Error as SecpError;
use bitcoin::secp256k1;
-use std::{cmp, mem};
+use io;
+use prelude::*;
+use core::cmp;
+use ln::chan_utils;
+use util::transaction_utils::sort_outputs;
+use ln::channel::INITIAL_COMMITMENT_NUMBER;
+use core::ops::Deref;
+use chain;
-const MAX_ALLOC_SIZE: usize = 64*1024;
+pub(crate) const MAX_HTLCS: u16 = 483;
pub(super) const HTLC_SUCCESS_TX_WEIGHT: u64 = 703;
pub(super) const HTLC_TIMEOUT_TX_WEIGHT: u64 = 663;
/// Allows us to keep track of all of the revocation secrets of counterarties in just 50*32 bytes
/// or so.
#[derive(Clone)]
-pub(super) struct CounterpartyCommitmentSecrets {
+pub(crate) struct CounterpartyCommitmentSecrets {
old_secrets: [([u8; 32], u64); 49],
}
}
impl CounterpartyCommitmentSecrets {
- pub(super) fn new() -> Self {
+ pub(crate) fn new() -> Self {
Self { old_secrets: [([0; 32], 1 << 48); 49], }
}
48
}
- pub(super) fn get_min_seen_secret(&self) -> u64 {
+ pub(crate) fn get_min_seen_secret(&self) -> u64 {
//TODO This can be optimized?
let mut min = 1 << 48;
for &(_, idx) in self.old_secrets.iter() {
}
#[inline]
- pub(super) fn derive_secret(secret: [u8; 32], bits: u8, idx: u64) -> [u8; 32] {
+ fn derive_secret(secret: [u8; 32], bits: u8, idx: u64) -> [u8; 32] {
let mut res: [u8; 32] = secret;
for i in 0..bits {
let bitpos = bits - 1 - i;
res
}
- pub(super) fn provide_secret(&mut self, idx: u64, secret: [u8; 32]) -> Result<(), ()> {
+ pub(crate) fn provide_secret(&mut self, idx: u64, secret: [u8; 32]) -> Result<(), ()> {
let pos = Self::place_secret(idx);
for i in 0..pos {
let (old_secret, old_idx) = self.old_secrets[i as usize];
}
/// Can only fail if idx is < get_min_seen_secret
- pub(super) fn get_secret(&self, idx: u64) -> Option<[u8; 32]> {
+ pub(crate) fn get_secret(&self, idx: u64) -> Option<[u8; 32]> {
for i in 0..self.old_secrets.len() {
if (idx & (!((1 << i) - 1))) == self.old_secrets[i].1 {
return Some(Self::derive_secret(self.old_secrets[i].0, i as u8, idx))
}
impl Writeable for CounterpartyCommitmentSecrets {
- fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
+ fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
for &(ref secret, ref idx) in self.old_secrets.iter() {
writer.write_all(secret)?;
writer.write_all(&byte_utils::be64_to_array(*idx))?;
}
+ write_tlv_fields!(writer, {});
Ok(())
}
}
impl Readable for CounterpartyCommitmentSecrets {
- fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
+ fn read<R: io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
let mut old_secrets = [([0; 32], 1 << 48); 49];
for &mut (ref mut secret, ref mut idx) in old_secrets.iter_mut() {
*secret = Readable::read(reader)?;
*idx = Readable::read(reader)?;
}
-
+ read_tlv_fields!(reader, {});
Ok(Self { old_secrets })
}
}
///
/// These keys are assumed to be good, either because the code derived them from
/// channel basepoints via the new function, or they were obtained via
-/// PreCalculatedTxCreationKeys.trust_key_derivation because we trusted the source of the
+/// CommitmentTransaction.trust().keys() because we trusted the source of the
/// pre-calculated keys.
#[derive(PartialEq, Clone)]
pub struct TxCreationKeys {
/// Broadcaster's Payment Key (which isn't allowed to be spent from for some delay)
pub broadcaster_delayed_payment_key: PublicKey,
}
-impl_writeable!(TxCreationKeys, 33*6,
- { per_commitment_point, revocation_key, broadcaster_htlc_key, countersignatory_htlc_key, broadcaster_delayed_payment_key });
-
-/// The per-commitment point and a set of pre-calculated public keys used for transaction creation
-/// in the signer.
-/// The pre-calculated keys are an optimization, because ChannelKeys has enough
-/// information to re-derive them.
-pub struct PreCalculatedTxCreationKeys(TxCreationKeys);
-
-impl PreCalculatedTxCreationKeys {
- /// Create a new PreCalculatedTxCreationKeys from TxCreationKeys
- pub fn new(keys: TxCreationKeys) -> Self {
- PreCalculatedTxCreationKeys(keys)
- }
- /// The pre-calculated transaction creation public keys.
- /// An external validating signer should not trust these keys.
- pub fn trust_key_derivation(&self) -> &TxCreationKeys {
- &self.0
- }
-
- /// The transaction per-commitment point
- pub fn per_commitment_point(&self) -> &PublicKey {
- &self.0.per_commitment_point
- }
-}
+impl_writeable_tlv_based!(TxCreationKeys, {
+ (0, per_commitment_point, required),
+ (2, revocation_key, required),
+ (4, broadcaster_htlc_key, required),
+ (6, countersignatory_htlc_key, required),
+ (8, broadcaster_delayed_payment_key, required),
+});
/// One counterparty's public keys which do not change over the life of a channel.
#[derive(Clone, PartialEq)]
/// counterparty to create a secret which the counterparty can reveal to revoke previous
/// states.
pub revocation_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.
+ /// The public key on which the non-broadcaster (ie the countersignatory) receives an immediately
+ /// spendable primary channel balance on the broadcaster's commitment transaction. 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
pub htlc_basepoint: PublicKey,
}
-impl_writeable!(ChannelPublicKeys, 33*5, {
- funding_pubkey,
- revocation_basepoint,
- payment_point,
- delayed_payment_basepoint,
- htlc_basepoint
+impl_writeable_tlv_based!(ChannelPublicKeys, {
+ (0, funding_pubkey, required),
+ (2, revocation_basepoint, required),
+ (4, payment_point, required),
+ (6, delayed_payment_basepoint, required),
+ (8, htlc_basepoint, required),
});
-
impl TxCreationKeys {
- /// Create a new TxCreationKeys from channel base points and the per-commitment point
+ /// Create per-state keys from channel base points and the per-commitment point.
+ /// Key set is asymmetric and can't be used as part of counter-signatory set of transactions.
pub fn derive_new<T: secp256k1::Signing + secp256k1::Verification>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, broadcaster_delayed_payment_base: &PublicKey, broadcaster_htlc_base: &PublicKey, countersignatory_revocation_base: &PublicKey, countersignatory_htlc_base: &PublicKey) -> Result<TxCreationKeys, SecpError> {
Ok(TxCreationKeys {
per_commitment_point: per_commitment_point.clone(),
broadcaster_delayed_payment_key: derive_public_key(&secp_ctx, &per_commitment_point, &broadcaster_delayed_payment_base)?,
})
}
+
+ /// Generate per-state keys from channel static keys.
+ /// Key set is asymmetric and can't be used as part of counter-signatory set of transactions.
+ pub fn from_channel_static_keys<T: secp256k1::Signing + secp256k1::Verification>(per_commitment_point: &PublicKey, broadcaster_keys: &ChannelPublicKeys, countersignatory_keys: &ChannelPublicKeys, secp_ctx: &Secp256k1<T>) -> Result<TxCreationKeys, SecpError> {
+ TxCreationKeys::derive_new(
+ &secp_ctx,
+ &per_commitment_point,
+ &broadcaster_keys.delayed_payment_basepoint,
+ &broadcaster_keys.htlc_basepoint,
+ &countersignatory_keys.revocation_basepoint,
+ &countersignatory_keys.htlc_basepoint,
+ )
+ }
}
+/// The maximum length of a script returned by get_revokeable_redeemscript.
+// Calculated as 6 bytes of opcodes, 1 byte push plus 2 bytes for contest_delay, and two public
+// keys of 33 bytes (+ 1 push).
+pub const REVOKEABLE_REDEEMSCRIPT_MAX_LENGTH: usize = 6 + 3 + 34*2;
+
/// A script either spendable by the revocation
/// key or the broadcaster_delayed_payment_key and satisfying the relative-locktime OP_CSV constrain.
-/// Encumbering a `to_local` output on a commitment transaction or 2nd-stage HTLC transactions.
+/// Encumbering a `to_holder` output on a commitment transaction or 2nd-stage HTLC transactions.
pub fn get_revokeable_redeemscript(revocation_key: &PublicKey, contest_delay: u16, broadcaster_delayed_payment_key: &PublicKey) -> Script {
- Builder::new().push_opcode(opcodes::all::OP_IF)
+ let res = Builder::new().push_opcode(opcodes::all::OP_IF)
.push_slice(&revocation_key.serialize())
.push_opcode(opcodes::all::OP_ELSE)
.push_int(contest_delay as i64)
.push_slice(&broadcaster_delayed_payment_key.serialize())
.push_opcode(opcodes::all::OP_ENDIF)
.push_opcode(opcodes::all::OP_CHECKSIG)
- .into_script()
+ .into_script();
+ debug_assert!(res.len() <= REVOKEABLE_REDEEMSCRIPT_MAX_LENGTH);
+ res
}
#[derive(Clone, PartialEq)]
/// Whether the HTLC was "offered" (ie outbound in relation to this commitment transaction).
/// Note that this is not the same as whether it is ountbound *from us*. To determine that you
/// need to compare this value to whether the commitment transaction in question is that of
- /// the remote party or our own.
+ /// the counterparty or our own.
pub offered: bool,
/// The value, in msat, of the HTLC. The value as it appears in the commitment transaction is
/// this divided by 1000.
pub transaction_output_index: Option<u32>,
}
-impl_writeable!(HTLCOutputInCommitment, 1 + 8 + 4 + 32 + 5, {
- offered,
- amount_msat,
- cltv_expiry,
- payment_hash,
- transaction_output_index
+impl_writeable_tlv_based!(HTLCOutputInCommitment, {
+ (0, offered, required),
+ (2, amount_msat, required),
+ (4, cltv_expiry, required),
+ (6, payment_hash, required),
+ (8, transaction_output_index, option),
});
#[inline]
}
}
-/// note here that 'revocation_key' is generated using countersignatory_revocation_basepoint and broadcaster's
-/// commitment secret. 'htlc' does *not* need to have its previous_output_index filled.
+/// Gets the witness redeemscript for an HTLC output in a commitment transaction. Note that htlc
+/// does not need to have its previous_output_index filled.
#[inline]
pub fn get_htlc_redeemscript(htlc: &HTLCOutputInCommitment, keys: &TxCreationKeys) -> Script {
get_htlc_redeemscript_with_explicit_keys(htlc, &keys.broadcaster_htlc_key, &keys.countersignatory_htlc_key, &keys.revocation_key)
}.push_opcode(opcodes::all::OP_PUSHNUM_2).push_opcode(opcodes::all::OP_CHECKMULTISIG).into_script()
}
-/// panics if htlc.transaction_output_index.is_none()!
-pub fn build_htlc_transaction(prev_hash: &Txid, feerate_per_kw: u32, contest_delay: u16, htlc: &HTLCOutputInCommitment, broadcaster_delayed_payment_key: &PublicKey, revocation_key: &PublicKey) -> Transaction {
+/// Builds an unsigned HTLC-Success or HTLC-Timeout transaction from the given channel and HTLC
+/// parameters. This is used by [`TrustedCommitmentTransaction::get_htlc_sigs`] to fetch the
+/// transaction which needs signing, and can be used to construct an HTLC transaction which is
+/// broadcastable given a counterparty HTLC signature.
+///
+/// Panics if htlc.transaction_output_index.is_none() (as such HTLCs do not appear in the
+/// commitment transaction).
+pub fn build_htlc_transaction(commitment_txid: &Txid, feerate_per_kw: u32, contest_delay: u16, htlc: &HTLCOutputInCommitment, broadcaster_delayed_payment_key: &PublicKey, revocation_key: &PublicKey) -> Transaction {
let mut txins: Vec<TxIn> = Vec::new();
txins.push(TxIn {
previous_output: OutPoint {
- txid: prev_hash.clone(),
+ txid: commitment_txid.clone(),
vout: htlc.transaction_output_index.expect("Can't build an HTLC transaction for a dust output"),
},
script_sig: Script::new(),
}
}
+/// Per-channel data used to build transactions in conjunction with the per-commitment data (CommitmentTransaction).
+/// The fields are organized by holder/counterparty.
+///
+/// Normally, this is converted to the broadcaster/countersignatory-organized DirectedChannelTransactionParameters
+/// before use, via the as_holder_broadcastable and as_counterparty_broadcastable functions.
#[derive(Clone)]
-/// We use this to track local commitment transactions and put off signing them until we are ready
-/// to broadcast. This class can be used inside a signer implementation to generate a signature
-/// given the relevant secret key.
-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,
- pub(crate) 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: u32,
- /// 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>)>,
+pub struct ChannelTransactionParameters {
+ /// Holder public keys
+ pub holder_pubkeys: ChannelPublicKeys,
+ /// The contest delay selected by the holder, which applies to counterparty-broadcast transactions
+ pub holder_selected_contest_delay: u16,
+ /// Whether the holder is the initiator of this channel.
+ /// This is an input to the commitment number obscure factor computation.
+ pub is_outbound_from_holder: bool,
+ /// The late-bound counterparty channel transaction parameters.
+ /// These parameters are populated at the point in the protocol where the counterparty provides them.
+ pub counterparty_parameters: Option<CounterpartyChannelTransactionParameters>,
+ /// The late-bound funding outpoint
+ pub funding_outpoint: Option<chain::transaction::OutPoint>,
}
-impl LocalCommitmentTransaction {
- #[cfg(test)]
- pub fn dummy() -> Self {
- 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(),
- broadcaster_htlc_key: dummy_key.clone(),
- countersignatory_htlc_key: dummy_key.clone(),
- broadcaster_delayed_payment_key: dummy_key.clone(),
- },
- feerate_per_kw: 0,
- per_htlc: Vec::new()
+
+/// Late-bound per-channel counterparty data used to build transactions.
+#[derive(Clone)]
+pub struct CounterpartyChannelTransactionParameters {
+ /// Counter-party public keys
+ pub pubkeys: ChannelPublicKeys,
+ /// The contest delay selected by the counterparty, which applies to holder-broadcast transactions
+ pub selected_contest_delay: u16,
+}
+
+impl ChannelTransactionParameters {
+ /// Whether the late bound parameters are populated.
+ pub fn is_populated(&self) -> bool {
+ self.counterparty_parameters.is_some() && self.funding_outpoint.is_some()
+ }
+
+ /// Convert the holder/counterparty parameters to broadcaster/countersignatory-organized parameters,
+ /// given that the holder is the broadcaster.
+ ///
+ /// self.is_populated() must be true before calling this function.
+ pub fn as_holder_broadcastable(&self) -> DirectedChannelTransactionParameters {
+ assert!(self.is_populated(), "self.late_parameters must be set before using as_holder_broadcastable");
+ DirectedChannelTransactionParameters {
+ inner: self,
+ holder_is_broadcaster: true
}
}
- /// Generate a new LocalCommitmentTransaction based on a raw commitment transaction,
- /// remote signature and both parties keys.
+ /// Convert the holder/counterparty parameters to broadcaster/countersignatory-organized parameters,
+ /// given that the counterparty is the broadcaster.
///
- /// The unsigned transaction outputs must be consistent with htlc_data. This function
- /// only checks that the shape and amounts are consistent, but does not check the scriptPubkey.
- pub 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: u32, 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?"); }
-
- for htlc in &htlc_data {
- if let Some(index) = htlc.0.transaction_output_index {
- let out = &unsigned_tx.output[index as usize];
- if out.value != htlc.0.amount_msat / 1000 {
- panic!("HTLC at index {} has incorrect amount", index);
- }
- if !out.script_pubkey.is_v0_p2wsh() {
- panic!("HTLC at index {} doesn't have p2wsh scriptPubkey", index);
- }
- }
+ /// self.is_populated() must be true before calling this function.
+ pub fn as_counterparty_broadcastable(&self) -> DirectedChannelTransactionParameters {
+ assert!(self.is_populated(), "self.late_parameters must be set before using as_counterparty_broadcastable");
+ DirectedChannelTransactionParameters {
+ inner: self,
+ holder_is_broadcaster: false
}
+ }
+}
- 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,
+impl_writeable_tlv_based!(CounterpartyChannelTransactionParameters, {
+ (0, pubkeys, required),
+ (2, selected_contest_delay, required),
+});
+
+impl_writeable_tlv_based!(ChannelTransactionParameters, {
+ (0, holder_pubkeys, required),
+ (2, holder_selected_contest_delay, required),
+ (4, is_outbound_from_holder, required),
+ (6, counterparty_parameters, option),
+ (8, funding_outpoint, option),
+});
+
+/// Static channel fields used to build transactions given per-commitment fields, organized by
+/// broadcaster/countersignatory.
+///
+/// This is derived from the holder/counterparty-organized ChannelTransactionParameters via the
+/// as_holder_broadcastable and as_counterparty_broadcastable functions.
+pub struct DirectedChannelTransactionParameters<'a> {
+ /// The holder's channel static parameters
+ inner: &'a ChannelTransactionParameters,
+ /// Whether the holder is the broadcaster
+ holder_is_broadcaster: bool,
+}
+
+impl<'a> DirectedChannelTransactionParameters<'a> {
+ /// Get the channel pubkeys for the broadcaster
+ pub fn broadcaster_pubkeys(&self) -> &ChannelPublicKeys {
+ if self.holder_is_broadcaster {
+ &self.inner.holder_pubkeys
+ } else {
+ &self.inner.counterparty_parameters.as_ref().unwrap().pubkeys
}
}
- /// The pre-calculated transaction creation public keys.
- /// An external validating signer should not trust these keys.
- pub fn trust_key_derivation(&self) -> &TxCreationKeys {
- &self.local_keys
+ /// Get the channel pubkeys for the countersignatory
+ pub fn countersignatory_pubkeys(&self) -> &ChannelPublicKeys {
+ if self.holder_is_broadcaster {
+ &self.inner.counterparty_parameters.as_ref().unwrap().pubkeys
+ } else {
+ &self.inner.holder_pubkeys
+ }
}
- /// Get the txid of the local commitment transaction contained in this
- /// LocalCommitmentTransaction
- pub fn txid(&self) -> Txid {
- self.unsigned_tx.txid()
+ /// Get the contest delay applicable to the transactions.
+ /// Note that the contest delay was selected by the countersignatory.
+ pub fn contest_delay(&self) -> u16 {
+ let counterparty_parameters = self.inner.counterparty_parameters.as_ref().unwrap();
+ if self.holder_is_broadcaster { counterparty_parameters.selected_contest_delay } else { self.inner.holder_selected_contest_delay }
}
- /// Gets our signature for the contained commitment transaction given our funding private key.
+ /// Whether the channel is outbound from the broadcaster.
///
- /// 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::SigHashCache::new(&self.unsigned_tx)
- .signature_hash(0, funding_redeemscript, channel_value_satoshis, SigHashType::All)[..]);
- secp_ctx.sign(&sighash, funding_key)
+ /// The boolean representing the side that initiated the channel is
+ /// an input to the commitment number obscure factor computation.
+ pub fn is_outbound(&self) -> bool {
+ if self.holder_is_broadcaster { self.inner.is_outbound_from_holder } else { !self.inner.is_outbound_from_holder }
+ }
+
+ /// The funding outpoint
+ pub fn funding_outpoint(&self) -> OutPoint {
+ self.inner.funding_outpoint.unwrap().into_bitcoin_outpoint()
+ }
+}
+
+/// Information needed to build and sign a holder's commitment transaction.
+///
+/// The transaction is only signed once we are ready to broadcast.
+#[derive(Clone)]
+pub struct HolderCommitmentTransaction {
+ inner: CommitmentTransaction,
+ /// Our counterparty's signature for the transaction
+ pub counterparty_sig: Signature,
+ /// All non-dust counterparty HTLC signatures, in the order they appear in the transaction
+ pub counterparty_htlc_sigs: Vec<Signature>,
+ // Which order the signatures should go in when constructing the final commitment tx witness.
+ // The user should be able to reconstruct this themselves, so we don't bother to expose it.
+ holder_sig_first: bool,
+}
+
+impl Deref for HolderCommitmentTransaction {
+ type Target = CommitmentTransaction;
+
+ fn deref(&self) -> &Self::Target { &self.inner }
+}
+
+impl PartialEq for HolderCommitmentTransaction {
+ // We dont care whether we are signed in equality comparison
+ fn eq(&self, o: &Self) -> bool {
+ self.inner == o.inner
+ }
+}
+
+impl_writeable_tlv_based!(HolderCommitmentTransaction, {
+ (0, inner, required),
+ (2, counterparty_sig, required),
+ (4, holder_sig_first, required),
+ (6, counterparty_htlc_sigs, vec_type),
+});
+
+impl HolderCommitmentTransaction {
+ #[cfg(test)]
+ pub fn dummy() -> Self {
+ let secp_ctx = Secp256k1::new();
+ let dummy_key = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
+ let dummy_sig = secp_ctx.sign(&secp256k1::Message::from_slice(&[42; 32]).unwrap(), &SecretKey::from_slice(&[42; 32]).unwrap());
+
+ let keys = TxCreationKeys {
+ per_commitment_point: dummy_key.clone(),
+ revocation_key: dummy_key.clone(),
+ broadcaster_htlc_key: dummy_key.clone(),
+ countersignatory_htlc_key: dummy_key.clone(),
+ broadcaster_delayed_payment_key: dummy_key.clone(),
+ };
+ let channel_pubkeys = ChannelPublicKeys {
+ funding_pubkey: dummy_key.clone(),
+ revocation_basepoint: dummy_key.clone(),
+ payment_point: dummy_key.clone(),
+ delayed_payment_basepoint: dummy_key.clone(),
+ htlc_basepoint: dummy_key.clone()
+ };
+ let channel_parameters = ChannelTransactionParameters {
+ holder_pubkeys: channel_pubkeys.clone(),
+ holder_selected_contest_delay: 0,
+ is_outbound_from_holder: false,
+ counterparty_parameters: Some(CounterpartyChannelTransactionParameters { pubkeys: channel_pubkeys.clone(), selected_contest_delay: 0 }),
+ funding_outpoint: Some(chain::transaction::OutPoint { txid: Default::default(), index: 0 })
+ };
+ let mut htlcs_with_aux: Vec<(_, ())> = Vec::new();
+ let inner = CommitmentTransaction::new_with_auxiliary_htlc_data(0, 0, 0, keys, 0, &mut htlcs_with_aux, &channel_parameters.as_counterparty_broadcastable());
+ HolderCommitmentTransaction {
+ inner,
+ counterparty_sig: dummy_sig,
+ counterparty_htlc_sigs: Vec::new(),
+ holder_sig_first: false
+ }
+ }
+
+ /// Create a new holder transaction with the given counterparty signatures.
+ /// The funding keys are used to figure out which signature should go first when building the transaction for broadcast.
+ pub fn new(commitment_tx: CommitmentTransaction, counterparty_sig: Signature, counterparty_htlc_sigs: Vec<Signature>, holder_funding_key: &PublicKey, counterparty_funding_key: &PublicKey) -> Self {
+ Self {
+ inner: commitment_tx,
+ counterparty_sig,
+ counterparty_htlc_sigs,
+ holder_sig_first: holder_funding_key.serialize()[..] < counterparty_funding_key.serialize()[..],
+ }
}
- pub(crate) fn add_local_sig(&self, funding_redeemscript: &Script, our_sig: Signature) -> Transaction {
- let mut tx = self.unsigned_tx.clone();
+ pub(crate) fn add_holder_sig(&self, funding_redeemscript: &Script, holder_sig: Signature) -> Transaction {
// First push the multisig dummy, note that due to BIP147 (NULLDUMMY) it must be a zero-length element.
+ let mut tx = self.inner.built.transaction.clone();
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());
+ if self.holder_sig_first {
+ tx.input[0].witness.push(holder_sig.serialize_der().to_vec());
+ tx.input[0].witness.push(self.counterparty_sig.serialize_der().to_vec());
} else {
- 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.push(self.counterparty_sig.serialize_der().to_vec());
+ tx.input[0].witness.push(holder_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
}
+}
+
+/// A pre-built Bitcoin commitment transaction and its txid.
+#[derive(Clone)]
+pub struct BuiltCommitmentTransaction {
+ /// The commitment transaction
+ pub transaction: Transaction,
+ /// The txid for the commitment transaction.
+ ///
+ /// This is provided as a performance optimization, instead of calling transaction.txid()
+ /// multiple times.
+ pub txid: Txid,
+}
+
+impl_writeable_tlv_based!(BuiltCommitmentTransaction, {
+ (0, transaction, required),
+ (2, txid, required),
+});
+
+impl BuiltCommitmentTransaction {
+ /// 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.transaction).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 to
+/// 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.
+///
+/// This class can be used inside a signer implementation to generate a signature given the relevant
+/// secret key.
+#[derive(Clone)]
+pub struct CommitmentTransaction {
+ commitment_number: u64,
+ to_broadcaster_value_sat: u64,
+ to_countersignatory_value_sat: u64,
+ feerate_per_kw: u32,
+ htlcs: Vec<HTLCOutputInCommitment>,
+ // A cache of the parties' pubkeys required to construct the transaction, see doc for trust()
+ keys: TxCreationKeys,
+ // For access to the pre-built transaction, see doc for trust()
+ built: BuiltCommitmentTransaction,
+}
+
+impl PartialEq for CommitmentTransaction {
+ fn eq(&self, o: &Self) -> bool {
+ let eq = self.commitment_number == o.commitment_number &&
+ self.to_broadcaster_value_sat == o.to_broadcaster_value_sat &&
+ self.to_countersignatory_value_sat == o.to_countersignatory_value_sat &&
+ self.feerate_per_kw == o.feerate_per_kw &&
+ self.htlcs == o.htlcs &&
+ self.keys == o.keys;
+ if eq {
+ debug_assert_eq!(self.built.transaction, o.built.transaction);
+ debug_assert_eq!(self.built.txid, o.built.txid);
+ }
+ eq
+ }
+}
+
+impl_writeable_tlv_based!(CommitmentTransaction, {
+ (0, commitment_number, required),
+ (2, to_broadcaster_value_sat, required),
+ (4, to_countersignatory_value_sat, required),
+ (6, feerate_per_kw, required),
+ (8, keys, required),
+ (10, built, required),
+ (12, htlcs, vec_type),
+});
+
+impl CommitmentTransaction {
+ /// Construct an object of the class while assigning transaction output indices to HTLCs.
+ ///
+ /// Populates HTLCOutputInCommitment.transaction_output_index in htlcs_with_aux.
+ ///
+ /// The generic T allows the caller to match the HTLC output index with auxiliary data.
+ /// This auxiliary data is not stored in this object.
+ ///
+ /// Only include HTLCs that are above the dust limit for the channel.
+ ///
+ /// (C-not exported) due to the generic though we likely should expose a version without
+ pub fn new_with_auxiliary_htlc_data<T>(commitment_number: u64, to_broadcaster_value_sat: u64, to_countersignatory_value_sat: u64, keys: TxCreationKeys, feerate_per_kw: u32, htlcs_with_aux: &mut Vec<(HTLCOutputInCommitment, T)>, channel_parameters: &DirectedChannelTransactionParameters) -> CommitmentTransaction {
+ // Sort outputs and populate output indices while keeping track of the auxiliary data
+ let (outputs, htlcs) = Self::internal_build_outputs(&keys, to_broadcaster_value_sat, to_countersignatory_value_sat, htlcs_with_aux, channel_parameters).unwrap();
+
+ let (obscured_commitment_transaction_number, txins) = Self::internal_build_inputs(commitment_number, channel_parameters);
+ let transaction = Self::make_transaction(obscured_commitment_transaction_number, txins, outputs);
+ let txid = transaction.txid();
+ CommitmentTransaction {
+ commitment_number,
+ to_broadcaster_value_sat,
+ to_countersignatory_value_sat,
+ feerate_per_kw,
+ htlcs,
+ keys,
+ built: BuiltCommitmentTransaction {
+ transaction,
+ txid
+ },
+ }
+ }
+
+ fn internal_rebuild_transaction(&self, keys: &TxCreationKeys, channel_parameters: &DirectedChannelTransactionParameters) -> Result<BuiltCommitmentTransaction, ()> {
+ let (obscured_commitment_transaction_number, txins) = Self::internal_build_inputs(self.commitment_number, channel_parameters);
+
+ let mut htlcs_with_aux = self.htlcs.iter().map(|h| (h.clone(), ())).collect();
+ let (outputs, _) = Self::internal_build_outputs(keys, self.to_broadcaster_value_sat, self.to_countersignatory_value_sat, &mut htlcs_with_aux, channel_parameters)?;
+
+ let transaction = Self::make_transaction(obscured_commitment_transaction_number, txins, outputs);
+ let txid = transaction.txid();
+ let built_transaction = BuiltCommitmentTransaction {
+ transaction,
+ txid
+ };
+ Ok(built_transaction)
+ }
+
+ fn make_transaction(obscured_commitment_transaction_number: u64, txins: Vec<TxIn>, outputs: Vec<TxOut>) -> Transaction {
+ Transaction {
+ version: 2,
+ lock_time: ((0x20 as u32) << 8 * 3) | ((obscured_commitment_transaction_number & 0xffffffu64) as u32),
+ input: txins,
+ output: outputs,
+ }
+ }
+
+ // This is used in two cases:
+ // - initial sorting of outputs / HTLCs in the constructor, in which case T is auxiliary data the
+ // caller needs to have sorted together with the HTLCs so it can keep track of the output index
+ // - building of a bitcoin transaction during a verify() call, in which case T is just ()
+ fn internal_build_outputs<T>(keys: &TxCreationKeys, to_broadcaster_value_sat: u64, to_countersignatory_value_sat: u64, htlcs_with_aux: &mut Vec<(HTLCOutputInCommitment, T)>, channel_parameters: &DirectedChannelTransactionParameters) -> Result<(Vec<TxOut>, Vec<HTLCOutputInCommitment>), ()> {
+ let countersignatory_pubkeys = channel_parameters.countersignatory_pubkeys();
+ let contest_delay = channel_parameters.contest_delay();
+
+ 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);
+ txouts.push((
+ TxOut {
+ script_pubkey: script.clone(),
+ value: to_countersignatory_value_sat,
+ },
+ None,
+ ))
+ }
+
+ if to_broadcaster_value_sat > 0 {
+ let redeem_script = get_revokeable_redeemscript(
+ &keys.revocation_key,
+ contest_delay,
+ &keys.broadcaster_delayed_payment_key,
+ );
+ txouts.push((
+ TxOut {
+ script_pubkey: redeem_script.to_v0_p2wsh(),
+ value: to_broadcaster_value_sat,
+ },
+ None,
+ ));
+ }
+
+ let mut htlcs = Vec::with_capacity(htlcs_with_aux.len());
+ for (htlc, _) in htlcs_with_aux {
+ let script = chan_utils::get_htlc_redeemscript(&htlc, &keys);
+ let txout = TxOut {
+ script_pubkey: script.to_v0_p2wsh(),
+ value: htlc.amount_msat / 1000,
+ };
+ txouts.push((txout, Some(htlc)));
+ }
+
+ // Sort output in BIP-69 order (amount, scriptPubkey). Tie-breaks based on HTLC
+ // CLTV expiration height.
+ sort_outputs(&mut txouts, |a, b| {
+ if let &Some(ref a_htlcout) = a {
+ if let &Some(ref b_htlcout) = b {
+ a_htlcout.cltv_expiry.cmp(&b_htlcout.cltv_expiry)
+ // Note that due to hash collisions, we have to have a fallback comparison
+ // here for fuzztarget mode (otherwise at least chanmon_fail_consistency
+ // may fail)!
+ .then(a_htlcout.payment_hash.0.cmp(&b_htlcout.payment_hash.0))
+ // For non-HTLC outputs, if they're copying our SPK we don't really care if we
+ // close the channel due to mismatches - they're doing something dumb:
+ } else { cmp::Ordering::Equal }
+ } else { cmp::Ordering::Equal }
+ });
+
+ let mut outputs = Vec::with_capacity(txouts.len());
+ for (idx, out) in txouts.drain(..).enumerate() {
+ if let Some(htlc) = out.1 {
+ htlc.transaction_output_index = Some(idx as u32);
+ htlcs.push(htlc.clone());
+ }
+ outputs.push(out.0);
+ }
+ Ok((outputs, htlcs))
+ }
+
+ fn internal_build_inputs(commitment_number: u64, channel_parameters: &DirectedChannelTransactionParameters) -> (u64, Vec<TxIn>) {
+ let broadcaster_pubkeys = channel_parameters.broadcaster_pubkeys();
+ let countersignatory_pubkeys = channel_parameters.countersignatory_pubkeys();
+ let commitment_transaction_number_obscure_factor = get_commitment_transaction_number_obscure_factor(
+ &broadcaster_pubkeys.payment_point,
+ &countersignatory_pubkeys.payment_point,
+ channel_parameters.is_outbound(),
+ );
+
+ let obscured_commitment_transaction_number =
+ commitment_transaction_number_obscure_factor ^ (INITIAL_COMMITMENT_NUMBER - commitment_number);
+
+ let txins = {
+ let mut ins: Vec<TxIn> = Vec::new();
+ ins.push(TxIn {
+ previous_output: channel_parameters.funding_outpoint(),
+ script_sig: Script::new(),
+ sequence: ((0x80 as u32) << 8 * 3)
+ | ((obscured_commitment_transaction_number >> 3 * 8) as u32),
+ witness: Vec::new(),
+ });
+ ins
+ };
+ (obscured_commitment_transaction_number, txins)
+ }
+
+ /// The backwards-counting commitment number
+ pub fn commitment_number(&self) -> u64 {
+ self.commitment_number
+ }
+
+ /// The value to be sent to the broadcaster
+ pub fn to_broadcaster_value_sat(&self) -> u64 {
+ self.to_broadcaster_value_sat
+ }
+
+ /// The value to be sent to the counterparty
+ pub fn to_countersignatory_value_sat(&self) -> u64 {
+ self.to_countersignatory_value_sat
+ }
+
+ /// The feerate paid per 1000-weight-unit in this commitment transaction.
+ pub fn feerate_per_kw(&self) -> u32 {
+ self.feerate_per_kw
+ }
+
+ /// The non-dust HTLCs (direction, amt, height expiration, hash, transaction output index)
+ /// which were included in this commitment transaction in output order.
+ /// The transaction index is always populated.
+ ///
+ /// (C-not exported) as we cannot currently convert Vec references to/from C, though we should
+ /// expose a less effecient version which creates a Vec of references in the future.
+ pub fn htlcs(&self) -> &Vec<HTLCOutputInCommitment> {
+ &self.htlcs
+ }
+
+ /// Trust our pre-built transaction and derived transaction creation public keys.
+ ///
+ /// 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.
+ pub fn trust(&self) -> TrustedCommitmentTransaction {
+ TrustedCommitmentTransaction { inner: self }
+ }
+
+ /// Verify our pre-built transaction and derived transaction creation public keys.
+ ///
+ /// Applies a wrapper which allows access to these fields.
+ ///
+ /// An external validating signer must call this method before signing
+ /// or using the built transaction.
+ pub fn verify<T: secp256k1::Signing + secp256k1::Verification>(&self, channel_parameters: &DirectedChannelTransactionParameters, broadcaster_keys: &ChannelPublicKeys, countersignatory_keys: &ChannelPublicKeys, secp_ctx: &Secp256k1<T>) -> Result<TrustedCommitmentTransaction, ()> {
+ // This is the only field of the key cache that we trust
+ let per_commitment_point = self.keys.per_commitment_point;
+ let keys = TxCreationKeys::from_channel_static_keys(&per_commitment_point, broadcaster_keys, countersignatory_keys, secp_ctx).unwrap();
+ if keys != self.keys {
+ return Err(());
+ }
+ let tx = self.internal_rebuild_transaction(&keys, channel_parameters)?;
+ if self.built.transaction != tx.transaction || self.built.txid != tx.txid {
+ return Err(());
+ }
+ Ok(TrustedCommitmentTransaction { inner: self })
+ }
+}
+
+/// A wrapper on CommitmentTransaction indicating that the derived fields (the built bitcoin
+/// transaction and the transaction creation keys) are trusted.
+///
+/// See trust() and verify() functions on CommitmentTransaction.
+///
+/// This structure implements Deref.
+pub struct TrustedCommitmentTransaction<'a> {
+ inner: &'a CommitmentTransaction,
+}
+
+impl<'a> Deref for TrustedCommitmentTransaction<'a> {
+ type Target = CommitmentTransaction;
+
+ fn deref(&self) -> &Self::Target { self.inner }
+}
+
+impl<'a> TrustedCommitmentTransaction<'a> {
+ /// The transaction ID of the built Bitcoin transaction
+ pub fn txid(&self) -> Txid {
+ self.inner.built.txid
+ }
+
+ /// The pre-built Bitcoin commitment transaction
+ pub fn built_transaction(&self) -> &BuiltCommitmentTransaction {
+ &self.inner.built
+ }
+
+ /// The pre-calculated transaction creation public keys.
+ pub fn keys(&self) -> &TxCreationKeys {
+ &self.inner.keys
+ }
/// 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.broadcaster_delayed_payment_key, &self.local_keys.revocation_key);
-
- let htlc_redeemscript = get_htlc_redeemscript_with_explicit_keys(&this_htlc.0, &self.local_keys.broadcaster_htlc_key, &self.local_keys.countersignatory_htlc_key, &self.local_keys.revocation_key);
-
- let sighash = hash_to_message!(&bip143::SigHashCache::new(&htlc_tx).signature_hash(0, &htlc_redeemscript, this_htlc.0.amount_msat / 1000, SigHashType::All)[..]);
- ret.push(Some(secp_ctx.sign(&sighash, &our_htlc_key)));
- } else {
- ret.push(None);
- }
+ /// The returned Vec has one entry for each HTLC, and in the same order.
+ pub fn get_htlc_sigs<T: secp256k1::Signing>(&self, htlc_base_key: &SecretKey, channel_parameters: &DirectedChannelTransactionParameters, secp_ctx: &Secp256k1<T>) -> Result<Vec<Signature>, ()> {
+ let inner = self.inner;
+ let keys = &inner.keys;
+ let txid = inner.built.txid;
+ let mut ret = Vec::with_capacity(inner.htlcs.len());
+ let holder_htlc_key = derive_private_key(secp_ctx, &inner.keys.per_commitment_point, htlc_base_key).map_err(|_| ())?;
+
+ for this_htlc in inner.htlcs.iter() {
+ assert!(this_htlc.transaction_output_index.is_some());
+ let htlc_tx = build_htlc_transaction(&txid, inner.feerate_per_kw, channel_parameters.contest_delay(), &this_htlc, &keys.broadcaster_delayed_payment_key, &keys.revocation_key);
+
+ let htlc_redeemscript = get_htlc_redeemscript_with_explicit_keys(&this_htlc, &keys.broadcaster_htlc_key, &keys.countersignatory_htlc_key, &keys.revocation_key);
+
+ let sighash = hash_to_message!(&bip143::SigHashCache::new(&htlc_tx).signature_hash(0, &htlc_redeemscript, this_htlc.amount_msat / 1000, SigHashType::All)[..]);
+ ret.push(secp_ctx.sign(&sighash, &holder_htlc_key));
}
Ok(ret)
}
- /// 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());
+ /// Gets a signed HTLC transaction given a preimage (for !htlc.offered) and the holder HTLC transaction signature.
+ pub(crate) fn get_signed_htlc_tx(&self, channel_parameters: &DirectedChannelTransactionParameters, htlc_index: usize, counterparty_signature: &Signature, signature: &Signature, preimage: &Option<PaymentPreimage>) -> Transaction {
+ let inner = self.inner;
+ let keys = &inner.keys;
+ let txid = inner.built.txid;
+ let this_htlc = &inner.htlcs[htlc_index];
+ assert!(this_htlc.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!(); }
+ if !this_htlc.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!(); }
+ if this_htlc.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.broadcaster_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 mut htlc_tx = build_htlc_transaction(&txid, inner.feerate_per_kw, channel_parameters.contest_delay(), &this_htlc, &keys.broadcaster_delayed_payment_key, &keys.revocation_key);
- let htlc_redeemscript = get_htlc_redeemscript_with_explicit_keys(&this_htlc.0, &self.local_keys.broadcaster_htlc_key, &self.local_keys.countersignatory_htlc_key, &self.local_keys.revocation_key);
+ let htlc_redeemscript = get_htlc_redeemscript_with_explicit_keys(&this_htlc, &keys.broadcaster_htlc_key, &keys.countersignatory_htlc_key, &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(counterparty_signature.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 {
+ if this_htlc.offered {
// Due to BIP146 (MINIMALIF) this must be a zero-length element to relay.
htlc_tx.input[0].witness.push(Vec::new());
} else {
htlc_tx
}
}
-impl PartialEq for LocalCommitmentTransaction {
- // We dont care whether we are signed in equality comparison
- fn eq(&self, o: &Self) -> bool {
- self.txid() == o.txid()
- }
-}
-impl Writeable for LocalCommitmentTransaction {
- fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
- 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(())
+
+/// Commitment transaction numbers which appear in the transactions themselves are XOR'd with a
+/// shared secret first. This prevents on-chain observers from discovering how many commitment
+/// transactions occurred in a channel before it was closed.
+///
+/// This function gets the shared secret from relevant channel public keys and can be used to
+/// "decrypt" the commitment transaction number given a commitment transaction on-chain.
+pub fn get_commitment_transaction_number_obscure_factor(
+ broadcaster_payment_basepoint: &PublicKey,
+ countersignatory_payment_basepoint: &PublicKey,
+ outbound_from_broadcaster: bool,
+) -> u64 {
+ let mut sha = Sha256::engine();
+
+ if outbound_from_broadcaster {
+ sha.input(&broadcaster_payment_basepoint.serialize());
+ sha.input(&countersignatory_payment_basepoint.serialize());
+ } else {
+ sha.input(&countersignatory_payment_basepoint.serialize());
+ sha.input(&broadcaster_payment_basepoint.serialize());
}
+ let res = Sha256::from_engine(sha).into_inner();
+
+ ((res[26] as u64) << 5 * 8)
+ | ((res[27] as u64) << 4 * 8)
+ | ((res[28] as u64) << 3 * 8)
+ | ((res[29] as u64) << 2 * 8)
+ | ((res[30] as u64) << 1 * 8)
+ | ((res[31] as u64) << 0 * 8)
}
-impl Readable for LocalCommitmentTransaction {
- fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
- 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 unsigned_tx.input.len() != 1 {
- // Ensure tx didn't hit the 0-input ambiguity case.
- return Err(DecodeError::InvalidValue);
- }
- Ok(Self {
- unsigned_tx,
- their_sig,
- our_sig_first,
- local_keys,
- feerate_per_kw,
- per_htlc,
- })
- }
+fn script_for_p2wpkh(key: &PublicKey) -> Script {
+ Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0)
+ .push_slice(&WPubkeyHash::hash(&key.serialize())[..])
+ .into_script()
}
#[cfg(test)]
mod tests {
use super::CounterpartyCommitmentSecrets;
use hex;
+ use prelude::*;
#[test]
fn test_per_commitment_storage() {
projects / rust-lightning / blobdiff