X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fln%2Fchan_utils.rs;h=994e1c276c4427168bca70a6aa1369bc7f1a741f;hb=843d25d750c3408d3f8f917764b8a58019a9dd81;hp=48b5046cced72ce3a935d0b4c54856a57353272d;hpb=c8bc1b6d3de45aeddc755d0875b3dce8d86f79c1;p=rust-lightning diff --git a/lightning/src/ln/chan_utils.rs b/lightning/src/ln/chan_utils.rs index 48b5046c..994e1c27 100644 --- a/lightning/src/ln/chan_utils.rs +++ b/lightning/src/ln/chan_utils.rs @@ -22,8 +22,8 @@ use bitcoin::hash_types::{Txid, PubkeyHash}; use ln::{PaymentHash, PaymentPreimage}; use ln::msgs::DecodeError; -use util::ser::{Readable, Writeable, Writer, MAX_BUF_SIZE}; -use util::byte_utils; +use util::ser::{Readable, Writeable, Writer}; +use util::{byte_utils, transaction_utils}; use bitcoin::hash_types::WPubkeyHash; use bitcoin::secp256k1::key::{SecretKey, PublicKey}; @@ -31,22 +31,17 @@ 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 std::io::Read; +use ln::channel::{INITIAL_COMMITMENT_NUMBER, ANCHOR_OUTPUT_VALUE_SATOSHI}; use core::ops::Deref; use chain; -// Maximum size of a serialized HTLCOutputInCommitment -pub(crate) const HTLC_OUTPUT_IN_COMMITMENT_SIZE: usize = 1 + 8 + 4 + 32 + 5; - pub(crate) const MAX_HTLCS: u16 = 483; -// This checks that the buffer size is greater than the maximum possible size for serialized HTLCS -const _EXCESS_BUFFER_SIZE: usize = MAX_BUF_SIZE - MAX_HTLCS as usize * HTLC_OUTPUT_IN_COMMITMENT_SIZE; - pub(super) const HTLC_SUCCESS_TX_WEIGHT: u64 = 703; pub(super) const HTLC_TIMEOUT_TX_WEIGHT: u64 = 663; @@ -85,6 +80,50 @@ 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). /// @@ -173,23 +212,23 @@ 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))?; } - write_tlv_fields!(writer, {}, {}); + write_tlv_fields!(writer, {}); Ok(()) } } 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)?; *idx = Readable::read(reader)?; } - read_tlv_fields!(reader, {}, {}); + read_tlv_fields!(reader, {}); Ok(Self { old_secrets }) } } @@ -324,12 +363,12 @@ pub struct TxCreationKeys { } impl_writeable_tlv_based!(TxCreationKeys, { - (0, per_commitment_point), - (2, revocation_key), - (4, broadcaster_htlc_key), - (6, countersignatory_htlc_key), - (8, broadcaster_delayed_payment_key), -}, {}, {}); + (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)] @@ -356,12 +395,12 @@ pub struct ChannelPublicKeys { } impl_writeable_tlv_based!(ChannelPublicKeys, { - (0, funding_pubkey), - (2, revocation_basepoint), - (4, payment_point), - (6, delayed_payment_basepoint), - (8, htlc_basepoint), -}, {}, {}); + (0, funding_pubkey, required), + (2, revocation_basepoint, required), + (4, payment_point, required), + (6, delayed_payment_basepoint, required), + (8, htlc_basepoint, required), +}); impl TxCreationKeys { /// Create per-state keys from channel base points and the per-commitment point. @@ -435,13 +474,12 @@ pub struct HTLCOutputInCommitment { } impl_writeable_tlv_based!(HTLCOutputInCommitment, { - (0, offered), - (2, amount_msat), - (4, cltv_expiry), - (6, payment_hash), -}, { - (8, transaction_output_index) -}, {}); + (0, offered, required), + (2, amount_msat, required), + (4, cltv_expiry, required), + (6, payment_hash, required), + (8, transaction_output_index, option), +}); #[inline] pub(crate) fn get_htlc_redeemscript_with_explicit_keys(htlc: &HTLCOutputInCommitment, broadcaster_htlc_key: &PublicKey, countersignatory_htlc_key: &PublicKey, revocation_key: &PublicKey) -> Script { @@ -531,12 +569,18 @@ pub fn make_funding_redeemscript(broadcaster: &PublicKey, countersignatory: &Pub }.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 = 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(), @@ -564,6 +608,24 @@ pub fn build_htlc_transaction(prev_hash: &Txid, feerate_per_kw: u32, contest_del } } +/// 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(crate) 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. /// @@ -626,18 +688,17 @@ impl ChannelTransactionParameters { } impl_writeable_tlv_based!(CounterpartyChannelTransactionParameters, { - (0, pubkeys), - (2, selected_contest_delay), -}, {}, {}); + (0, pubkeys, required), + (2, selected_contest_delay, required), +}); impl_writeable_tlv_based!(ChannelTransactionParameters, { - (0, holder_pubkeys), - (2, holder_selected_contest_delay), - (4, is_outbound_from_holder), -}, { - (6, counterparty_parameters), - (8, funding_outpoint), -}, {}); + (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. @@ -720,11 +781,10 @@ impl PartialEq for HolderCommitmentTransaction { } impl_writeable_tlv_based!(HolderCommitmentTransaction, { - (0, inner), - (2, counterparty_sig), - (4, holder_sig_first), -}, {}, { - (6, counterparty_htlc_sigs), + (0, inner, required), + (2, counterparty_sig, required), + (4, holder_sig_first, required), + (6, counterparty_htlc_sigs, vec_type), }); impl HolderCommitmentTransaction { @@ -756,7 +816,7 @@ impl HolderCommitmentTransaction { 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()); + 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, @@ -809,9 +869,9 @@ pub struct BuiltCommitmentTransaction { } impl_writeable_tlv_based!(BuiltCommitmentTransaction, { - (0, transaction), - (2, txid) -}, {}, {}); + (0, transaction, required), + (2, txid, required), +}); impl BuiltCommitmentTransaction { /// Get the SIGHASH_ALL sighash value of the transaction. @@ -830,7 +890,130 @@ 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. +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. /// @@ -843,6 +1026,8 @@ 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() @@ -856,6 +1041,7 @@ 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); @@ -865,44 +1051,16 @@ impl PartialEq for CommitmentTransaction { } } -/// (C-not exported) as users never need to call this directly -impl Writeable for Vec { - #[inline] - fn write(&self, w: &mut W) -> Result<(), ::std::io::Error> { - (self.len() as u16).write(w)?; - for e in self.iter() { - e.write(w)?; - } - Ok(()) - } -} - -/// (C-not exported) as users never need to call this directly -impl Readable for Vec { - #[inline] - fn read(r: &mut R) -> Result { - let len: u16 = Readable::read(r)?; - let byte_size = (len as usize) - .checked_mul(HTLC_OUTPUT_IN_COMMITMENT_SIZE) - .ok_or(DecodeError::BadLengthDescriptor)?; - if byte_size > MAX_BUF_SIZE { - return Err(DecodeError::BadLengthDescriptor); - } - let mut ret = Vec::with_capacity(len as usize); - for _ in 0..len { ret.push(HTLCOutputInCommitment::read(r)?); } - Ok(ret) - } -} - impl_writeable_tlv_based!(CommitmentTransaction, { - (0, commitment_number), - (2, to_broadcaster_value_sat), - (4, to_countersignatory_value_sat), - (6, feerate_per_kw), - (8, htlcs), - (10, keys), - (12, built), -}, {}, {}); + (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), + (14, opt_anchors, option), +}); impl CommitmentTransaction { /// Construct an object of the class while assigning transaction output indices to HTLCs. @@ -915,9 +1073,9 @@ 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); @@ -928,6 +1086,7 @@ impl CommitmentTransaction { to_countersignatory_value_sat, feerate_per_kw, htlcs, + opt_anchors: if opt_anchors { Some(()) } else { None }, keys, built: BuiltCommitmentTransaction { transaction, @@ -936,11 +1095,11 @@ 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(); @@ -964,7 +1123,7 @@ 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(); @@ -996,6 +1155,30 @@ 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); @@ -1094,7 +1277,7 @@ 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 } } @@ -1112,7 +1295,7 @@ 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(()); } @@ -1211,7 +1394,12 @@ impl<'a> TrustedCommitmentTransaction<'a> { } } -/// Get the transaction number obscure factor +/// 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, @@ -1245,7 +1433,105 @@ 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::{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; + + #[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 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 }) + }; + + 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); + + // 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); + + // 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); + + // Generate broadcaster output, an HTLC output and two anchors + let payment_hash = PaymentHash([42; 32]); + let htlc_info = HTLCOutputInCommitment { + offered: false, + amount_msat: 1000000, + cltv_expiry: 100, + payment_hash, + transaction_output_index: None, + }; + + 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![(htlc_info, ())], &channel_parameters.as_holder_broadcastable() + ); + assert_eq!(tx.built.transaction.output.len(), 4); + } #[test] fn test_per_commitment_storage() {