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per_commitment_point
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5 files changed

+29
-57
lines changed

5 files changed

+29
-57
lines changed

lightning/src/chain/channelmonitor.rs

+3
Original file line numberDiff line numberDiff line change
@@ -2547,6 +2547,9 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitorImpl<Signer> {
25472547
},
25482548
commitment_txid: htlc.commitment_txid,
25492549
per_commitment_number: htlc.per_commitment_number,
2550+
per_commitment_point: self.onchain_tx_handler.signer.get_per_commitment_point(
2551+
htlc.per_commitment_number, &self.onchain_tx_handler.secp_ctx
2552+
),
25502553
htlc: htlc.htlc,
25512554
preimage: htlc.preimage,
25522555
counterparty_sig: htlc.counterparty_sig,

lightning/src/events/bump_transaction.rs

+19-36
Original file line numberDiff line numberDiff line change
@@ -67,6 +67,8 @@ pub struct HTLCDescriptor {
6767
pub commitment_txid: Txid,
6868
/// The number of the commitment transaction in which the HTLC output lives.
6969
pub per_commitment_number: u64,
70+
/// The point that maps to the number of the commitment transaction in which the HTLC output lives.
71+
pub per_commitment_point: PublicKey,
7072
/// The details of the HTLC as it appears in the commitment transaction.
7173
pub htlc: HTLCOutputInCommitment,
7274
/// The preimage, if `Some`, to claim the HTLC output with. If `None`, the timeout path must be
@@ -85,17 +87,15 @@ impl HTLCDescriptor {
8587

8688
/// Returns the delayed output created as a result of spending the HTLC output in the commitment
8789
/// transaction.
88-
pub fn tx_output<C: secp256k1::Signing + secp256k1::Verification>(
89-
&self, per_commitment_point: &PublicKey, secp: &Secp256k1<C>
90-
) -> TxOut {
90+
pub fn tx_output<C: secp256k1::Signing + secp256k1::Verification>(&self, secp: &Secp256k1<C>) -> TxOut {
9191
let channel_params = self.signer_descriptor.channel_parameters.as_holder_broadcastable();
9292
let broadcaster_keys = channel_params.broadcaster_pubkeys();
9393
let counterparty_keys = channel_params.countersignatory_pubkeys();
9494
let broadcaster_delayed_key = chan_utils::derive_public_key(
95-
secp, per_commitment_point, &broadcaster_keys.delayed_payment_basepoint
95+
secp, &self.per_commitment_point, &broadcaster_keys.delayed_payment_basepoint
9696
);
9797
let counterparty_revocation_key = chan_utils::derive_public_revocation_key(
98-
secp, per_commitment_point, &counterparty_keys.revocation_basepoint
98+
secp, &self.per_commitment_point, &counterparty_keys.revocation_basepoint
9999
);
100100
chan_utils::build_htlc_output(
101101
0 /* feerate_per_kw */, channel_params.contest_delay(), &self.htlc, true /* opt_anchors */,
@@ -104,20 +104,18 @@ impl HTLCDescriptor {
104104
}
105105

106106
/// Returns the witness script of the HTLC output in the commitment transaction.
107-
pub fn witness_script<C: secp256k1::Signing + secp256k1::Verification>(
108-
&self, per_commitment_point: &PublicKey, secp: &Secp256k1<C>
109-
) -> Script {
107+
pub fn witness_script<C: secp256k1::Signing + secp256k1::Verification>(&self, secp: &Secp256k1<C>) -> Script {
110108
let channel_params = self.signer_descriptor.channel_parameters.as_holder_broadcastable();
111109
let broadcaster_keys = channel_params.broadcaster_pubkeys();
112110
let counterparty_keys = channel_params.countersignatory_pubkeys();
113111
let broadcaster_htlc_key = chan_utils::derive_public_key(
114-
secp, per_commitment_point, &broadcaster_keys.htlc_basepoint
112+
secp, &self.per_commitment_point, &broadcaster_keys.htlc_basepoint
115113
);
116114
let counterparty_htlc_key = chan_utils::derive_public_key(
117-
secp, per_commitment_point, &counterparty_keys.htlc_basepoint
115+
secp, &self.per_commitment_point, &counterparty_keys.htlc_basepoint
118116
);
119117
let counterparty_revocation_key = chan_utils::derive_public_revocation_key(
120-
secp, per_commitment_point, &counterparty_keys.revocation_basepoint
118+
secp, &self.per_commitment_point, &counterparty_keys.revocation_basepoint
121119
);
122120
chan_utils::get_htlc_redeemscript_with_explicit_keys(
123121
&self.htlc, true /* opt_anchors */, &broadcaster_htlc_key, &counterparty_htlc_key,
@@ -669,31 +667,15 @@ where
669667
fn build_htlc_tx(
670668
&self, claim_id: ClaimId, target_feerate_sat_per_1000_weight: u32,
671669
htlc_descriptors: &[HTLCDescriptor], tx_lock_time: PackedLockTime,
672-
) -> Result<(Transaction, HashMap<[u8; 32], <SP::Target as SignerProvider>::Signer>), ()> {
670+
) -> Result<Transaction, ()> {
673671
let mut tx = Transaction {
674672
version: 2,
675673
lock_time: tx_lock_time,
676674
input: vec![],
677675
output: vec![],
678676
};
679-
// Unfortunately, we need to derive the signer for each HTLC ahead of time to obtain its
680-
// input.
681-
let mut signers = HashMap::new();
682677
let mut must_spend = Vec::with_capacity(htlc_descriptors.len());
683678
for htlc_descriptor in htlc_descriptors {
684-
let signer = signers.entry(htlc_descriptor.signer_descriptor.channel_keys_id)
685-
.or_insert_with(|| {
686-
let mut signer = self.signer_provider.derive_channel_signer(
687-
htlc_descriptor.signer_descriptor.channel_value_satoshis,
688-
htlc_descriptor.signer_descriptor.channel_keys_id,
689-
);
690-
signer.provide_channel_parameters(&htlc_descriptor.signer_descriptor.channel_parameters);
691-
signer
692-
});
693-
let per_commitment_point = signer.get_per_commitment_point(
694-
htlc_descriptor.per_commitment_number, &self.secp
695-
);
696-
697679
let htlc_input = htlc_descriptor.unsigned_tx_input();
698680
must_spend.push(Input {
699681
outpoint: htlc_input.previous_output.clone(),
@@ -704,15 +686,15 @@ where
704686
},
705687
});
706688
tx.input.push(htlc_input);
707-
let htlc_output = htlc_descriptor.tx_output(&per_commitment_point, &self.secp);
689+
let htlc_output = htlc_descriptor.tx_output(&self.secp);
708690
tx.output.push(htlc_output);
709691
}
710692

711693
let coin_selection = self.utxo_source.select_confirmed_utxos(
712694
claim_id, &must_spend, &tx.output, target_feerate_sat_per_1000_weight,
713695
)?;
714696
self.process_coin_selection(&mut tx, coin_selection);
715-
Ok((tx, signers))
697+
Ok(tx)
716698
}
717699

718700
/// Handles a [`BumpTransactionEvent::HTLCResolution`] event variant by producing a
@@ -721,20 +703,21 @@ where
721703
&self, claim_id: ClaimId, target_feerate_sat_per_1000_weight: u32,
722704
htlc_descriptors: &[HTLCDescriptor], tx_lock_time: PackedLockTime,
723705
) -> Result<(), ()> {
724-
let (mut htlc_tx, signers) = self.build_htlc_tx(
706+
let mut htlc_tx = self.build_htlc_tx(
725707
claim_id, target_feerate_sat_per_1000_weight, htlc_descriptors, tx_lock_time,
726708
)?;
727709

728710
self.utxo_source.sign_tx(&mut htlc_tx)?;
729711
for (idx, htlc_descriptor) in htlc_descriptors.iter().enumerate() {
730-
let signer = signers.get(&htlc_descriptor.signer_descriptor.channel_keys_id).unwrap();
712+
let mut signer = self.signer_provider.derive_channel_signer(
713+
htlc_descriptor.signer_descriptor.channel_value_satoshis,
714+
htlc_descriptor.signer_descriptor.channel_keys_id,
715+
);
716+
signer.provide_channel_parameters(&htlc_descriptor.signer_descriptor.channel_parameters);
731717
let htlc_sig = signer.sign_holder_htlc_transaction(
732718
&htlc_tx, idx, htlc_descriptor, &self.secp
733719
)?;
734-
let per_commitment_point = signer.get_per_commitment_point(
735-
htlc_descriptor.per_commitment_number, &self.secp
736-
);
737-
let witness_script = htlc_descriptor.witness_script(&per_commitment_point, &self.secp);
720+
let witness_script = htlc_descriptor.witness_script(&self.secp);
738721
htlc_tx.input[idx].witness = htlc_descriptor.tx_input_witness(&htlc_sig, &witness_script);
739722
}
740723

lightning/src/ln/monitor_tests.rs

+4-14
Original file line numberDiff line numberDiff line change
@@ -1805,12 +1805,9 @@ fn do_test_monitor_rebroadcast_pending_claims(anchors: bool) {
18051805
&descriptor.signer_descriptor.channel_keys_id,
18061806
);
18071807
signer.provide_channel_parameters(&descriptor.signer_descriptor.channel_parameters);
1808-
let per_commitment_point = signer.get_per_commitment_point(
1809-
descriptor.per_commitment_number, &secp
1810-
);
1811-
tx.output.push(descriptor.tx_output(&per_commitment_point, &secp));
1808+
tx.output.push(descriptor.tx_output(&secp));
18121809
let our_sig = signer.sign_holder_htlc_transaction(&mut tx, 0, &descriptor, &secp).unwrap();
1813-
let witness_script = descriptor.witness_script(&per_commitment_point, &secp);
1810+
let witness_script = descriptor.witness_script(&secp);
18141811
tx.input[0].witness = descriptor.tx_input_witness(&our_sig, &witness_script);
18151812
target_feerate_sat_per_1000_weight as u64
18161813
} else { panic!("unexpected event"); };
@@ -2236,14 +2233,8 @@ fn test_anchors_aggregated_revoked_htlc_tx() {
22362233
assert_eq!(htlc_descriptors.len(), 2);
22372234
for htlc_descriptor in &htlc_descriptors {
22382235
assert!(!htlc_descriptor.htlc.offered);
2239-
let mut signer = nodes[1].keys_manager.derive_channel_keys(
2240-
htlc_descriptor.signer_descriptor.channel_value_satoshis,
2241-
&htlc_descriptor.signer_descriptor.channel_keys_id
2242-
);
2243-
signer.provide_channel_parameters(&htlc_descriptor.signer_descriptor.channel_parameters);
2244-
let per_commitment_point = signer.get_per_commitment_point(htlc_descriptor.per_commitment_number, &secp);
22452236
htlc_tx.input.push(htlc_descriptor.unsigned_tx_input());
2246-
htlc_tx.output.push(htlc_descriptor.tx_output(&per_commitment_point, &secp));
2237+
htlc_tx.output.push(htlc_descriptor.tx_output(&secp));
22472238
}
22482239
descriptors.append(&mut htlc_descriptors);
22492240
htlc_tx.lock_time = tx_lock_time;
@@ -2259,8 +2250,7 @@ fn test_anchors_aggregated_revoked_htlc_tx() {
22592250
);
22602251
signer.provide_channel_parameters(&htlc_descriptor.signer_descriptor.channel_parameters);
22612252
let our_sig = signer.sign_holder_htlc_transaction(&htlc_tx, htlc_input_idx, &htlc_descriptor, &secp).unwrap();
2262-
let per_commitment_point = signer.get_per_commitment_point(htlc_descriptor.per_commitment_number, &secp);
2263-
let witness_script = htlc_descriptor.witness_script(&per_commitment_point, &secp);
2253+
let witness_script = htlc_descriptor.witness_script(&secp);
22642254
htlc_tx.input[htlc_input_idx].witness = htlc_descriptor.tx_input_witness(&our_sig, &witness_script);
22652255
}
22662256
let fee_utxo_sig = {

lightning/src/sign/mod.rs

+2-5
Original file line numberDiff line numberDiff line change
@@ -1030,15 +1030,12 @@ impl EcdsaChannelSigner for InMemorySigner {
10301030
&self, htlc_tx: &Transaction, input: usize, htlc_descriptor: &HTLCDescriptor,
10311031
secp_ctx: &Secp256k1<secp256k1::All>
10321032
) -> Result<Signature, ()> {
1033-
let per_commitment_point = self.get_per_commitment_point(
1034-
htlc_descriptor.per_commitment_number, &secp_ctx
1035-
);
1036-
let witness_script = htlc_descriptor.witness_script(&per_commitment_point, secp_ctx);
1033+
let witness_script = htlc_descriptor.witness_script(secp_ctx);
10371034
let sighash = &sighash::SighashCache::new(&*htlc_tx).segwit_signature_hash(
10381035
input, &witness_script, htlc_descriptor.htlc.amount_msat / 1000, EcdsaSighashType::All
10391036
).map_err(|_| ())?;
10401037
let our_htlc_private_key = chan_utils::derive_private_key(
1041-
&secp_ctx, &per_commitment_point, &self.htlc_base_key
1038+
&secp_ctx, &htlc_descriptor.per_commitment_point, &self.htlc_base_key
10421039
);
10431040
Ok(sign_with_aux_rand(&secp_ctx, &hash_to_message!(sighash), &our_htlc_private_key, &self))
10441041
}

lightning/src/util/enforcing_trait_impls.rs

+1-2
Original file line numberDiff line numberDiff line change
@@ -210,9 +210,8 @@ impl EcdsaChannelSigner for EnforcingSigner {
210210
&self, htlc_tx: &Transaction, input: usize, htlc_descriptor: &HTLCDescriptor,
211211
secp_ctx: &Secp256k1<secp256k1::All>
212212
) -> Result<Signature, ()> {
213-
let per_commitment_point = self.get_per_commitment_point(htlc_descriptor.per_commitment_number, secp_ctx);
214213
assert_eq!(htlc_tx.input[input], htlc_descriptor.unsigned_tx_input());
215-
assert_eq!(htlc_tx.output[input], htlc_descriptor.tx_output(&per_commitment_point, secp_ctx));
214+
assert_eq!(htlc_tx.output[input], htlc_descriptor.tx_output(secp_ctx));
216215
Ok(self.inner.sign_holder_htlc_transaction(htlc_tx, input, htlc_descriptor, secp_ctx).unwrap())
217216
}
218217

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