X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fln%2Fchan_utils.rs;h=6dc05c2ef3c09e2fcd5fc16ad8a2ebe2427343d3;hb=996d3d8058f2342b9e23d53f9dd81ae472822120;hp=6e0e50858f8972ff90865eb3c23f5c2ce39f10fa;hpb=4353d4a11c12c148fbf3e95dd2e2f824f60433df;p=rust-lightning diff --git a/lightning/src/ln/chan_utils.rs b/lightning/src/ln/chan_utils.rs index 6e0e5085..6dc05c2e 100644 --- a/lightning/src/ln/chan_utils.rs +++ b/lightning/src/ln/chan_utils.rs @@ -23,7 +23,7 @@ use bitcoin::hash_types::{Txid, PubkeyHash}; 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}; @@ -31,18 +31,32 @@ use bitcoin::secp256k1::{Secp256k1, Signature, Message}; use bitcoin::secp256k1::Error as SecpError; use bitcoin::secp256k1; +use io; use prelude::*; use core::cmp; use ln::chan_utils; use util::transaction_utils::sort_outputs; -use ln::channel::INITIAL_COMMITMENT_NUMBER; +use ln::channel::{INITIAL_COMMITMENT_NUMBER, ANCHOR_OUTPUT_VALUE_SATOSHI}; use core::ops::Deref; use chain; 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; +/// Gets the weight for an HTLC-Success transaction. +#[inline] +pub fn htlc_success_tx_weight(opt_anchors: bool) -> u64 { + const HTLC_SUCCESS_TX_WEIGHT: u64 = 703; + const HTLC_SUCCESS_ANCHOR_TX_WEIGHT: u64 = 706; + if opt_anchors { HTLC_SUCCESS_ANCHOR_TX_WEIGHT } else { HTLC_SUCCESS_TX_WEIGHT } +} + +/// Gets the weight for an HTLC-Timeout transaction. +#[inline] +pub fn htlc_timeout_tx_weight(opt_anchors: bool) -> u64 { + const HTLC_TIMEOUT_TX_WEIGHT: u64 = 663; + const HTLC_TIMEOUT_ANCHOR_TX_WEIGHT: u64 = 666; + if opt_anchors { HTLC_TIMEOUT_ANCHOR_TX_WEIGHT } else { HTLC_TIMEOUT_TX_WEIGHT } +} #[derive(PartialEq)] pub(crate) enum HTLCType { @@ -79,13 +93,57 @@ pub fn build_commitment_secret(commitment_seed: &[u8; 32], idx: u64) -> [u8; 32] 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 = 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 = 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). /// -/// Allows us to keep track of all of the revocation secrets of counterarties in just 50*32 bytes +/// Allows us to keep track of all of the revocation secrets of our counterparty in just 50*32 bytes /// or so. #[derive(Clone)] -pub(crate) struct CounterpartyCommitmentSecrets { +pub struct CounterpartyCommitmentSecrets { old_secrets: [([u8; 32], u64); 49], } @@ -101,7 +159,8 @@ impl PartialEq for CounterpartyCommitmentSecrets { } impl CounterpartyCommitmentSecrets { - pub(crate) fn new() -> Self { + /// Creates a new empty `CounterpartyCommitmentSecrets` structure. + pub fn new() -> Self { Self { old_secrets: [([0; 32], 1 << 48); 49], } } @@ -115,7 +174,9 @@ impl CounterpartyCommitmentSecrets { 48 } - pub(crate) fn get_min_seen_secret(&self) -> u64 { + /// Returns the minimum index of all stored secrets. Note that indexes start + /// at 1 << 48 and get decremented by one for each new secret. + pub fn get_min_seen_secret(&self) -> u64 { //TODO This can be optimized? let mut min = 1 << 48; for &(_, idx) in self.old_secrets.iter() { @@ -139,7 +200,9 @@ impl CounterpartyCommitmentSecrets { res } - pub(crate) fn provide_secret(&mut self, idx: u64, secret: [u8; 32]) -> Result<(), ()> { + /// Inserts the `secret` at `idx`. Returns `Ok(())` if the secret + /// was generated in accordance with BOLT 3 and is consistent with previous secrets. + pub 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]; @@ -154,8 +217,9 @@ impl CounterpartyCommitmentSecrets { Ok(()) } - /// Can only fail if idx is < get_min_seen_secret - pub(crate) fn get_secret(&self, idx: u64) -> Option<[u8; 32]> { + /// Returns the secret at `idx`. + /// Returns `None` if `idx` is < [`CounterpartyCommitmentSecrets::get_min_seen_secret`]. + pub 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)) @@ -167,7 +231,7 @@ impl CounterpartyCommitmentSecrets { } impl Writeable for CounterpartyCommitmentSecrets { - fn write(&self, writer: &mut W) -> Result<(), ::std::io::Error> { + fn write(&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))?; @@ -177,7 +241,7 @@ impl Writeable for CounterpartyCommitmentSecrets { } } impl Readable for CounterpartyCommitmentSecrets { - fn read(reader: &mut R) -> Result { + fn read(reader: &mut R) -> Result { 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)?; @@ -437,10 +501,10 @@ impl_writeable_tlv_based!(HTLCOutputInCommitment, { }); #[inline] -pub(crate) fn get_htlc_redeemscript_with_explicit_keys(htlc: &HTLCOutputInCommitment, broadcaster_htlc_key: &PublicKey, countersignatory_htlc_key: &PublicKey, revocation_key: &PublicKey) -> Script { +pub(crate) fn get_htlc_redeemscript_with_explicit_keys(htlc: &HTLCOutputInCommitment, opt_anchors: bool, broadcaster_htlc_key: &PublicKey, countersignatory_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) + let mut bldr = Builder::new().push_opcode(opcodes::all::OP_DUP) .push_opcode(opcodes::all::OP_HASH160) .push_slice(&PubkeyHash::hash(&revocation_key.serialize())[..]) .push_opcode(opcodes::all::OP_EQUAL) @@ -464,11 +528,16 @@ pub(crate) fn get_htlc_redeemscript_with_explicit_keys(htlc: &HTLCOutputInCommit .push_slice(&payment_hash160) .push_opcode(opcodes::all::OP_EQUALVERIFY) .push_opcode(opcodes::all::OP_CHECKSIG) - .push_opcode(opcodes::all::OP_ENDIF) - .push_opcode(opcodes::all::OP_ENDIF) - .into_script() + .push_opcode(opcodes::all::OP_ENDIF); + if opt_anchors { + bldr = bldr.push_opcode(opcodes::all::OP_PUSHNUM_1) + .push_opcode(opcodes::all::OP_CSV) + .push_opcode(opcodes::all::OP_DROP); + } + bldr.push_opcode(opcodes::all::OP_ENDIF) + .into_script() } else { - Builder::new().push_opcode(opcodes::all::OP_DUP) + let mut bldr = Builder::new().push_opcode(opcodes::all::OP_DUP) .push_opcode(opcodes::all::OP_HASH160) .push_slice(&PubkeyHash::hash(&revocation_key.serialize())[..]) .push_opcode(opcodes::all::OP_EQUAL) @@ -495,17 +564,22 @@ pub(crate) fn get_htlc_redeemscript_with_explicit_keys(htlc: &HTLCOutputInCommit .push_opcode(opcodes::all::OP_CLTV) .push_opcode(opcodes::all::OP_DROP) .push_opcode(opcodes::all::OP_CHECKSIG) - .push_opcode(opcodes::all::OP_ENDIF) - .push_opcode(opcodes::all::OP_ENDIF) - .into_script() + .push_opcode(opcodes::all::OP_ENDIF); + if opt_anchors { + bldr = bldr.push_opcode(opcodes::all::OP_PUSHNUM_1) + .push_opcode(opcodes::all::OP_CSV) + .push_opcode(opcodes::all::OP_DROP); + } + bldr.push_opcode(opcodes::all::OP_ENDIF) + .into_script() } } /// 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) +pub fn get_htlc_redeemscript(htlc: &HTLCOutputInCommitment, opt_anchors: bool, keys: &TxCreationKeys) -> Script { + get_htlc_redeemscript_with_explicit_keys(htlc, opt_anchors, &keys.broadcaster_htlc_key, &keys.countersignatory_htlc_key, &keys.revocation_key) } /// Gets the redeemscript for a funding output from the two funding public keys. @@ -531,7 +605,7 @@ pub fn make_funding_redeemscript(broadcaster: &PublicKey, countersignatory: &Pub /// /// 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 { +pub fn build_htlc_transaction(commitment_txid: &Txid, feerate_per_kw: u32, contest_delay: u16, htlc: &HTLCOutputInCommitment, opt_anchors: bool, broadcaster_delayed_payment_key: &PublicKey, revocation_key: &PublicKey) -> Transaction { let mut txins: Vec = Vec::new(); txins.push(TxIn { previous_output: OutPoint { @@ -539,15 +613,16 @@ pub fn build_htlc_transaction(commitment_txid: &Txid, feerate_per_kw: u32, conte vout: htlc.transaction_output_index.expect("Can't build an HTLC transaction for a dust output"), }, script_sig: Script::new(), - sequence: 0, + sequence: if opt_anchors { 1 } else { 0 }, witness: Vec::new(), }); - let total_fee = if htlc.offered { - feerate_per_kw as u64 * HTLC_TIMEOUT_TX_WEIGHT / 1000 - } else { - feerate_per_kw as u64 * HTLC_SUCCESS_TX_WEIGHT / 1000 - }; + let weight = if htlc.offered { + htlc_timeout_tx_weight(opt_anchors) + } else { + htlc_success_tx_weight(opt_anchors) + }; + let total_fee = feerate_per_kw as u64 * weight / 1000; let mut txouts: Vec = Vec::new(); txouts.push(TxOut { @@ -563,6 +638,35 @@ pub fn build_htlc_transaction(commitment_txid: &Txid, feerate_per_kw: u32, conte } } +/// Gets the witnessScript for the to_remote output when anchors are enabled. +#[inline] +pub(crate) fn get_to_countersignatory_with_anchors_redeemscript(payment_point: &PublicKey) -> Script { + Builder::new() + .push_slice(&payment_point.serialize()[..]) + .push_opcode(opcodes::all::OP_CHECKSIGVERIFY) + .push_int(1) + .push_opcode(opcodes::all::OP_CSV) + .into_script() +} + +/// Gets the witnessScript for an anchor output from the funding public key. +/// The witness in the spending input must be: +/// +/// After 16 blocks of confirmation, an alternative satisfying witness could be: +/// <> +/// (empty vector required to satisfy compliance with MINIMALIF-standard rule) +#[inline] +pub fn get_anchor_redeemscript(funding_pubkey: &PublicKey) -> Script { + Builder::new().push_slice(&funding_pubkey.serialize()[..]) + .push_opcode(opcodes::all::OP_CHECKSIG) + .push_opcode(opcodes::all::OP_IFDUP) + .push_opcode(opcodes::all::OP_NOTIF) + .push_int(16) + .push_opcode(opcodes::all::OP_CSV) + .push_opcode(opcodes::all::OP_ENDIF) + .into_script() +} + /// Per-channel data used to build transactions in conjunction with the per-commitment data (CommitmentTransaction). /// The fields are organized by holder/counterparty. /// @@ -582,6 +686,8 @@ pub struct ChannelTransactionParameters { pub counterparty_parameters: Option, /// The late-bound funding outpoint pub funding_outpoint: Option, + /// Are anchors used for this channel. Boolean is serialization backwards-compatible + pub opt_anchors: Option<()> } /// Late-bound per-channel counterparty data used to build transactions. @@ -635,6 +741,7 @@ impl_writeable_tlv_based!(ChannelTransactionParameters, { (4, is_outbound_from_holder, required), (6, counterparty_parameters, option), (8, funding_outpoint, option), + (10, opt_anchors, option), }); /// Static channel fields used to build transactions given per-commitment fields, organized by @@ -687,6 +794,11 @@ impl<'a> DirectedChannelTransactionParameters<'a> { pub fn funding_outpoint(&self) -> OutPoint { self.inner.funding_outpoint.unwrap().into_bitcoin_outpoint() } + + /// Whether to use anchors for this channel + pub fn opt_anchors(&self) -> bool { + self.inner.opt_anchors.is_some() + } } /// Information needed to build and sign a holder's commitment transaction. @@ -750,10 +862,11 @@ impl HolderCommitmentTransaction { 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 }) + funding_outpoint: Some(chain::transaction::OutPoint { txid: Default::default(), index: 0 }), + opt_anchors: None }; 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()); + let inner = CommitmentTransaction::new_with_auxiliary_htlc_data(0, 0, 0, false, dummy_key.clone(), dummy_key.clone(), keys, 0, &mut htlcs_with_aux, &channel_parameters.as_counterparty_broadcastable()); HolderCommitmentTransaction { inner, counterparty_sig: dummy_sig, @@ -827,7 +940,131 @@ impl BuiltCommitmentTransaction { } } -/// 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. +#[derive(Clone, Hash, PartialEq)] +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 { + 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(&self, funding_key: &SecretKey, funding_redeemscript: &Script, channel_value_satoshis: u64, secp_ctx: &Secp256k1) -> 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. /// @@ -840,6 +1077,8 @@ pub struct CommitmentTransaction { to_countersignatory_value_sat: u64, feerate_per_kw: u32, htlcs: Vec, + // A boolean that is serialization backwards-compatible + opt_anchors: Option<()>, // 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() @@ -853,6 +1092,7 @@ impl PartialEq for CommitmentTransaction { self.to_countersignatory_value_sat == o.to_countersignatory_value_sat && self.feerate_per_kw == o.feerate_per_kw && self.htlcs == o.htlcs && + self.opt_anchors == o.opt_anchors && self.keys == o.keys; if eq { debug_assert_eq!(self.built.transaction, o.built.transaction); @@ -870,6 +1110,7 @@ impl_writeable_tlv_based!(CommitmentTransaction, { (8, keys, required), (10, built, required), (12, htlcs, vec_type), + (14, opt_anchors, option), }); impl CommitmentTransaction { @@ -883,9 +1124,9 @@ impl CommitmentTransaction { /// 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(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 { + pub fn new_with_auxiliary_htlc_data(commitment_number: u64, to_broadcaster_value_sat: u64, to_countersignatory_value_sat: u64, opt_anchors: bool, broadcaster_funding_key: PublicKey, countersignatory_funding_key: PublicKey, 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 (outputs, htlcs) = Self::internal_build_outputs(&keys, to_broadcaster_value_sat, to_countersignatory_value_sat, htlcs_with_aux, channel_parameters, opt_anchors, &broadcaster_funding_key, &countersignatory_funding_key).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); @@ -896,6 +1137,7 @@ impl CommitmentTransaction { to_countersignatory_value_sat, feerate_per_kw, htlcs, + opt_anchors: if opt_anchors { Some(()) } else { None }, keys, built: BuiltCommitmentTransaction { transaction, @@ -904,11 +1146,11 @@ impl CommitmentTransaction { } } - fn internal_rebuild_transaction(&self, keys: &TxCreationKeys, channel_parameters: &DirectedChannelTransactionParameters) -> Result { + fn internal_rebuild_transaction(&self, keys: &TxCreationKeys, channel_parameters: &DirectedChannelTransactionParameters, broadcaster_funding_key: &PublicKey, countersignatory_funding_key: &PublicKey) -> Result { 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 (outputs, _) = Self::internal_build_outputs(keys, self.to_broadcaster_value_sat, self.to_countersignatory_value_sat, &mut htlcs_with_aux, channel_parameters, self.opt_anchors.is_some(), broadcaster_funding_key, countersignatory_funding_key)?; let transaction = Self::make_transaction(obscured_commitment_transaction_number, txins, outputs); let txid = transaction.txid(); @@ -932,14 +1174,18 @@ impl CommitmentTransaction { // - 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(keys: &TxCreationKeys, to_broadcaster_value_sat: u64, to_countersignatory_value_sat: u64, htlcs_with_aux: &mut Vec<(HTLCOutputInCommitment, T)>, channel_parameters: &DirectedChannelTransactionParameters) -> Result<(Vec, Vec), ()> { + fn internal_build_outputs(keys: &TxCreationKeys, to_broadcaster_value_sat: u64, to_countersignatory_value_sat: u64, htlcs_with_aux: &mut Vec<(HTLCOutputInCommitment, T)>, channel_parameters: &DirectedChannelTransactionParameters, opt_anchors: bool, broadcaster_funding_key: &PublicKey, countersignatory_funding_key: &PublicKey) -> Result<(Vec, Vec), ()> { 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); + let script = if opt_anchors { + get_to_countersignatory_with_anchors_redeemscript(&countersignatory_pubkeys.payment_point).to_v0_p2wsh() + } else { + get_p2wpkh_redeemscript(&countersignatory_pubkeys.payment_point) + }; txouts.push(( TxOut { script_pubkey: script.clone(), @@ -964,9 +1210,33 @@ impl CommitmentTransaction { )); } + if opt_anchors { + if to_broadcaster_value_sat > 0 || !htlcs_with_aux.is_empty() { + let anchor_script = get_anchor_redeemscript(broadcaster_funding_key); + txouts.push(( + TxOut { + script_pubkey: anchor_script.to_v0_p2wsh(), + value: ANCHOR_OUTPUT_VALUE_SATOSHI, + }, + None, + )); + } + + if to_countersignatory_value_sat > 0 || !htlcs_with_aux.is_empty() { + let anchor_script = get_anchor_redeemscript(countersignatory_funding_key); + txouts.push(( + TxOut { + script_pubkey: anchor_script.to_v0_p2wsh(), + value: ANCHOR_OUTPUT_VALUE_SATOSHI, + }, + 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 script = chan_utils::get_htlc_redeemscript(&htlc, opt_anchors, &keys); let txout = TxOut { script_pubkey: script.to_v0_p2wsh(), value: htlc.amount_msat / 1000, @@ -981,7 +1251,7 @@ impl CommitmentTransaction { 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 + // here for fuzzing 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 @@ -1062,7 +1332,7 @@ impl CommitmentTransaction { /// 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 } } @@ -1080,7 +1350,7 @@ impl CommitmentTransaction { if keys != self.keys { return Err(()); } - let tx = self.internal_rebuild_transaction(&keys, channel_parameters)?; + let tx = self.internal_rebuild_transaction(&keys, channel_parameters, &broadcaster_keys.funding_pubkey, &countersignatory_keys.funding_pubkey)?; if self.built.transaction != tx.transaction || self.built.txid != tx.txid { return Err(()); } @@ -1120,10 +1390,17 @@ impl<'a> TrustedCommitmentTransaction<'a> { &self.inner.keys } + /// Should anchors be used. + pub fn opt_anchors(&self) -> bool { + self.opt_anchors.is_some() + } + /// 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. + /// + /// This function is only valid in the holder commitment context, it always uses SigHashType::All. pub fn get_htlc_sigs(&self, htlc_base_key: &SecretKey, channel_parameters: &DirectedChannelTransactionParameters, secp_ctx: &Secp256k1) -> Result, ()> { let inner = self.inner; let keys = &inner.keys; @@ -1133,9 +1410,9 @@ impl<'a> TrustedCommitmentTransaction<'a> { 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_tx = build_htlc_transaction(&txid, inner.feerate_per_kw, channel_parameters.contest_delay(), &this_htlc, self.opt_anchors(), &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 htlc_redeemscript = get_htlc_redeemscript_with_explicit_keys(&this_htlc, self.opt_anchors(), &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)); @@ -1155,16 +1432,18 @@ impl<'a> TrustedCommitmentTransaction<'a> { // Further, we should never be provided the preimage for an HTLC-Timeout transaction. if this_htlc.offered && preimage.is_some() { unreachable!(); } - 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 mut htlc_tx = build_htlc_transaction(&txid, inner.feerate_per_kw, channel_parameters.contest_delay(), &this_htlc, self.opt_anchors(), &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 htlc_redeemscript = get_htlc_redeemscript_with_explicit_keys(&this_htlc, self.opt_anchors(), &keys.broadcaster_htlc_key, &keys.countersignatory_htlc_key, &keys.revocation_key); + + let sighashtype = if self.opt_anchors() { SigHashType::SinglePlusAnyoneCanPay } else { SigHashType::All }; // 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(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[1].push(sighashtype as u8); htlc_tx.input[0].witness[2].push(SigHashType::All as u8); if this_htlc.offered { @@ -1209,7 +1488,7 @@ pub fn get_commitment_transaction_number_obscure_factor( | ((res[31] as u64) << 0 * 8) } -fn script_for_p2wpkh(key: &PublicKey) -> Script { +fn get_p2wpkh_redeemscript(key: &PublicKey) -> Script { Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0) .push_slice(&WPubkeyHash::hash(&key.serialize())[..]) .into_script() @@ -1218,8 +1497,142 @@ fn script_for_p2wpkh(key: &PublicKey) -> Script { #[cfg(test)] mod tests { use super::CounterpartyCommitmentSecrets; - use hex; + use ::{hex, chain}; use prelude::*; + use ln::chan_utils::{get_htlc_redeemscript, get_to_countersignatory_with_anchors_redeemscript, get_p2wpkh_redeemscript, CommitmentTransaction, TxCreationKeys, ChannelTransactionParameters, CounterpartyChannelTransactionParameters, HTLCOutputInCommitment}; + use bitcoin::secp256k1::{PublicKey, SecretKey, Secp256k1}; + use util::test_utils; + use chain::keysinterface::{KeysInterface, BaseSign}; + use bitcoin::Network; + use ln::PaymentHash; + use bitcoin::hashes::hex::ToHex; + + #[test] + fn test_anchors() { + let secp_ctx = Secp256k1::new(); + + let seed = [42; 32]; + let network = Network::Testnet; + let keys_provider = test_utils::TestKeysInterface::new(&seed, network); + let signer = keys_provider.get_channel_signer(false, 3000); + let counterparty_signer = keys_provider.get_channel_signer(false, 3000); + let delayed_payment_base = &signer.pubkeys().delayed_payment_basepoint; + let per_commitment_secret = SecretKey::from_slice(&hex::decode("1f1e1d1c1b1a191817161514131211100f0e0d0c0b0a09080706050403020100").unwrap()[..]).unwrap(); + let per_commitment_point = PublicKey::from_secret_key(&secp_ctx, &per_commitment_secret); + let htlc_basepoint = &signer.pubkeys().htlc_basepoint; + let holder_pubkeys = signer.pubkeys(); + let counterparty_pubkeys = counterparty_signer.pubkeys(); + let keys = TxCreationKeys::derive_new(&secp_ctx, &per_commitment_point, delayed_payment_base, htlc_basepoint, &counterparty_pubkeys.revocation_basepoint, &counterparty_pubkeys.htlc_basepoint).unwrap(); + let mut channel_parameters = ChannelTransactionParameters { + holder_pubkeys: holder_pubkeys.clone(), + holder_selected_contest_delay: 0, + is_outbound_from_holder: false, + counterparty_parameters: Some(CounterpartyChannelTransactionParameters { pubkeys: counterparty_pubkeys.clone(), selected_contest_delay: 0 }), + funding_outpoint: Some(chain::transaction::OutPoint { txid: Default::default(), index: 0 }), + opt_anchors: None + }; + + let mut htlcs_with_aux: Vec<(_, ())> = Vec::new(); + + // Generate broadcaster and counterparty outputs + let tx = CommitmentTransaction::new_with_auxiliary_htlc_data( + 0, 1000, 2000, + false, + holder_pubkeys.funding_pubkey, + counterparty_pubkeys.funding_pubkey, + keys.clone(), 1, + &mut htlcs_with_aux, &channel_parameters.as_holder_broadcastable() + ); + assert_eq!(tx.built.transaction.output.len(), 2); + assert_eq!(tx.built.transaction.output[1].script_pubkey, get_p2wpkh_redeemscript(&counterparty_pubkeys.payment_point)); + + // Generate broadcaster and counterparty outputs as well as two anchors + let tx = CommitmentTransaction::new_with_auxiliary_htlc_data( + 0, 1000, 2000, + true, + holder_pubkeys.funding_pubkey, + counterparty_pubkeys.funding_pubkey, + keys.clone(), 1, + &mut htlcs_with_aux, &channel_parameters.as_holder_broadcastable() + ); + assert_eq!(tx.built.transaction.output.len(), 4); + assert_eq!(tx.built.transaction.output[3].script_pubkey, get_to_countersignatory_with_anchors_redeemscript(&counterparty_pubkeys.payment_point).to_v0_p2wsh()); + + // Generate broadcaster output and anchor + let tx = CommitmentTransaction::new_with_auxiliary_htlc_data( + 0, 3000, 0, + true, + holder_pubkeys.funding_pubkey, + counterparty_pubkeys.funding_pubkey, + keys.clone(), 1, + &mut htlcs_with_aux, &channel_parameters.as_holder_broadcastable() + ); + assert_eq!(tx.built.transaction.output.len(), 2); + + // Generate counterparty output and anchor + let tx = CommitmentTransaction::new_with_auxiliary_htlc_data( + 0, 0, 3000, + true, + holder_pubkeys.funding_pubkey, + counterparty_pubkeys.funding_pubkey, + keys.clone(), 1, + &mut htlcs_with_aux, &channel_parameters.as_holder_broadcastable() + ); + assert_eq!(tx.built.transaction.output.len(), 2); + + let received_htlc = HTLCOutputInCommitment { + offered: false, + amount_msat: 400000, + cltv_expiry: 100, + payment_hash: PaymentHash([42; 32]), + transaction_output_index: None, + }; + + let offered_htlc = HTLCOutputInCommitment { + offered: true, + amount_msat: 600000, + cltv_expiry: 100, + payment_hash: PaymentHash([43; 32]), + transaction_output_index: None, + }; + + // Generate broadcaster output and received and offered HTLC outputs, w/o anchors + let tx = CommitmentTransaction::new_with_auxiliary_htlc_data( + 0, 3000, 0, + false, + holder_pubkeys.funding_pubkey, + counterparty_pubkeys.funding_pubkey, + keys.clone(), 1, + &mut vec![(received_htlc.clone(), ()), (offered_htlc.clone(), ())], + &channel_parameters.as_holder_broadcastable() + ); + assert_eq!(tx.built.transaction.output.len(), 3); + assert_eq!(tx.built.transaction.output[0].script_pubkey, get_htlc_redeemscript(&received_htlc, false, &keys).to_v0_p2wsh()); + assert_eq!(tx.built.transaction.output[1].script_pubkey, get_htlc_redeemscript(&offered_htlc, false, &keys).to_v0_p2wsh()); + assert_eq!(get_htlc_redeemscript(&received_htlc, false, &keys).to_v0_p2wsh().to_hex(), + "002085cf52e41ba7c099a39df504e7b61f6de122971ceb53b06731876eaeb85e8dc5"); + assert_eq!(get_htlc_redeemscript(&offered_htlc, false, &keys).to_v0_p2wsh().to_hex(), + "002049f0736bb335c61a04d2623a24df878a7592a3c51fa7258d41b2c85318265e73"); + + // Generate broadcaster output and received and offered HTLC outputs, with anchors + channel_parameters.opt_anchors = Some(()); + let tx = CommitmentTransaction::new_with_auxiliary_htlc_data( + 0, 3000, 0, + true, + holder_pubkeys.funding_pubkey, + counterparty_pubkeys.funding_pubkey, + keys.clone(), 1, + &mut vec![(received_htlc.clone(), ()), (offered_htlc.clone(), ())], + &channel_parameters.as_holder_broadcastable() + ); + assert_eq!(tx.built.transaction.output.len(), 5); + assert_eq!(tx.built.transaction.output[2].script_pubkey, get_htlc_redeemscript(&received_htlc, true, &keys).to_v0_p2wsh()); + assert_eq!(tx.built.transaction.output[3].script_pubkey, get_htlc_redeemscript(&offered_htlc, true, &keys).to_v0_p2wsh()); + assert_eq!(get_htlc_redeemscript(&received_htlc, true, &keys).to_v0_p2wsh().to_hex(), + "002067114123af3f95405bae4fd930fc95de03e3c86baaee8b2dd29b43dd26cf613c"); + assert_eq!(get_htlc_redeemscript(&offered_htlc, true, &keys).to_v0_p2wsh().to_hex(), + "0020a06e3b0d4fcf704f2b9c41e16a70099e39989466c3142b8573a1154542f28f57"); + } #[test] fn test_per_commitment_storage() {