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tankyleotankyleo
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Reorg return values of ChannelContext::build_commitment_transaction
We choose to include in `CommitmentStats` only fields that will be calculated or constructed by transaction builders. The other fields are created by channel, and placed in a new struct we call `CommitmentData`.
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‎lightning/src/ln/channel.rs‎

Lines changed: 77 additions & 44 deletions
Original file line numberDiff line numberDiff line change
@@ -877,15 +877,20 @@ struct HTLCStats {
877877
on_holder_tx_outbound_holding_cell_htlcs_count: u32, // dust HTLCs *non*-included
878878
}
879879

880-
/// An enum gathering stats on commitment transaction, either local or remote.
881-
struct CommitmentStats<'a> {
880+
/// A struct gathering data on a commitment, either local or remote.
881+
struct CommitmentData<'a> {
882+
stats: CommitmentStats,
883+
htlcs_included: Vec<(HTLCOutputInCommitment, Option<&'a HTLCSource>)>, // the list of HTLCs (dust HTLCs *included*) which were not ignored when building the transaction
884+
outbound_htlc_preimages: Vec<PaymentPreimage>, // preimages for successful offered HTLCs since last commitment
885+
inbound_htlc_preimages: Vec<PaymentPreimage>, // preimages for successful received HTLCs since last commitment
886+
}
887+
888+
/// A struct gathering stats on a commitment transaction, either local or remote.
889+
struct CommitmentStats {
882890
tx: CommitmentTransaction, // the transaction info
883891
total_fee_sat: u64, // the total fee included in the transaction
884-
htlcs_included: Vec<(HTLCOutputInCommitment, Option<&'a HTLCSource>)>, // the list of HTLCs (dust HTLCs *included*) which were not ignored when building the transaction
885892
local_balance_msat: u64, // local balance before fees *not* considering dust limits
886893
remote_balance_msat: u64, // remote balance before fees *not* considering dust limits
887-
outbound_htlc_preimages: Vec<PaymentPreimage>, // preimages for successful offered HTLCs since last commitment
888-
inbound_htlc_preimages: Vec<PaymentPreimage>, // preimages for successful received HTLCs since last commitment
889894
}
890895

891896
/// Used when calculating whether we or the remote can afford an additional HTLC.
@@ -2043,7 +2048,10 @@ trait InitialRemoteCommitmentReceiver<SP: Deref> where SP::Target: SignerProvide
20432048
) -> Result<CommitmentTransaction, ChannelError> where L::Target: Logger {
20442049
let funding_script = self.funding().get_funding_redeemscript();
20452050

2046-
let initial_commitment_tx = self.context().build_commitment_transaction(self.funding(), holder_commitment_point.transaction_number(), &holder_commitment_point.current_point(), true, false, logger).tx;
2051+
let commitment_data = self.context().build_commitment_transaction(self.funding(),
2052+
holder_commitment_point.transaction_number(), &holder_commitment_point.current_point(),
2053+
true, false, logger);
2054+
let initial_commitment_tx = commitment_data.stats.tx;
20472055
let trusted_tx = initial_commitment_tx.trust();
20482056
let initial_commitment_bitcoin_tx = trusted_tx.built_transaction();
20492057
let sighash = initial_commitment_bitcoin_tx.get_sighash_all(&funding_script, self.funding().get_value_satoshis());
@@ -2080,7 +2088,10 @@ trait InitialRemoteCommitmentReceiver<SP: Deref> where SP::Target: SignerProvide
20802088
}
20812089
};
20822090
let context = self.context();
2083-
let counterparty_initial_commitment_tx = context.build_commitment_transaction(self.funding(), context.cur_counterparty_commitment_transaction_number, &context.counterparty_cur_commitment_point.unwrap(), false, false, logger).tx;
2091+
let commitment_data = context.build_commitment_transaction(self.funding(),
2092+
context.cur_counterparty_commitment_transaction_number,
2093+
&context.counterparty_cur_commitment_point.unwrap(), false, false, logger);
2094+
let counterparty_initial_commitment_tx = commitment_data.stats.tx;
20842095
let counterparty_trusted_tx = counterparty_initial_commitment_tx.trust();
20852096
let counterparty_initial_bitcoin_tx = counterparty_trusted_tx.built_transaction();
20862097

@@ -3479,9 +3490,11 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider {
34793490
{
34803491
let funding_script = funding.get_funding_redeemscript();
34813492

3482-
let commitment_stats = self.build_commitment_transaction(funding, holder_commitment_point.transaction_number(), &holder_commitment_point.current_point(), true, false, logger);
3493+
let commitment_data = self.build_commitment_transaction(funding,
3494+
holder_commitment_point.transaction_number(), &holder_commitment_point.current_point(),
3495+
true, false, logger);
34833496
let commitment_txid = {
3484-
let trusted_tx = commitment_stats.tx.trust();
3497+
let trusted_tx = commitment_data.stats.tx.trust();
34853498
let bitcoin_tx = trusted_tx.built_transaction();
34863499
let sighash = bitcoin_tx.get_sighash_all(&funding_script, funding.get_value_satoshis());
34873500

@@ -3494,7 +3507,7 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider {
34943507
}
34953508
bitcoin_tx.txid
34963509
};
3497-
let mut htlcs_cloned: Vec<_> = commitment_stats.htlcs_included.iter().map(|htlc| (htlc.0.clone(), htlc.1.map(|h| h.clone()))).collect();
3510+
let mut htlcs_cloned: Vec<_> = commitment_data.htlcs_included.iter().map(|htlc| (htlc.0.clone(), htlc.1.map(|h| h.clone()))).collect();
34983511

34993512
// If our counterparty updated the channel fee in this commitment transaction, check that
35003513
// they can actually afford the new fee now.
@@ -3504,7 +3517,7 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider {
35043517
if update_fee {
35053518
debug_assert!(!funding.is_outbound());
35063519
let counterparty_reserve_we_require_msat = funding.holder_selected_channel_reserve_satoshis * 1000;
3507-
if commitment_stats.remote_balance_msat < commitment_stats.total_fee_sat * 1000 + counterparty_reserve_we_require_msat {
3520+
if commitment_data.stats.remote_balance_msat < commitment_data.stats.total_fee_sat * 1000 + counterparty_reserve_we_require_msat {
35083521
return Err(ChannelError::close("Funding remote cannot afford proposed new fee".to_owned()));
35093522
}
35103523
}
@@ -3520,14 +3533,14 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider {
35203533
&& info.next_holder_htlc_id == self.next_holder_htlc_id
35213534
&& info.next_counterparty_htlc_id == self.next_counterparty_htlc_id
35223535
&& info.feerate == self.feerate_per_kw {
3523-
assert_eq!(commitment_stats.total_fee_sat, info.fee / 1000);
3536+
assert_eq!(commitment_data.stats.total_fee_sat, info.fee / 1000);
35243537
}
35253538
}
35263539
}
35273540
}
35283541

3529-
if msg.htlc_signatures.len() != commitment_stats.tx.htlcs().len() {
3530-
return Err(ChannelError::close(format!("Got wrong number of HTLC signatures ({}) from remote. It must be {}", msg.htlc_signatures.len(), commitment_stats.tx.htlcs().len())));
3542+
if msg.htlc_signatures.len() != commitment_data.stats.tx.htlcs().len() {
3543+
return Err(ChannelError::close(format!("Got wrong number of HTLC signatures ({}) from remote. It must be {}", msg.htlc_signatures.len(), commitment_data.stats.tx.htlcs().len())));
35313544
}
35323545

35333546
// Up to LDK 0.0.115, HTLC information was required to be duplicated in the
@@ -3547,10 +3560,10 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider {
35473560

35483561
let mut nondust_htlc_sources = Vec::with_capacity(htlcs_cloned.len());
35493562
let mut htlcs_and_sigs = Vec::with_capacity(htlcs_cloned.len());
3550-
let holder_keys = commitment_stats.tx.trust().keys();
3563+
let holder_keys = commitment_data.stats.tx.trust().keys();
35513564
for (idx, (htlc, mut source_opt)) in htlcs_cloned.drain(..).enumerate() {
35523565
if let Some(_) = htlc.transaction_output_index {
3553-
let htlc_tx = chan_utils::build_htlc_transaction(&commitment_txid, commitment_stats.tx.feerate_per_kw(),
3566+
let htlc_tx = chan_utils::build_htlc_transaction(&commitment_txid, commitment_data.stats.tx.feerate_per_kw(),
35543567
funding.get_counterparty_selected_contest_delay().unwrap(), &htlc, &self.channel_type,
35553568
&holder_keys.broadcaster_delayed_payment_key, &holder_keys.revocation_key);
35563569

@@ -3578,14 +3591,14 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider {
35783591
}
35793592

35803593
let holder_commitment_tx = HolderCommitmentTransaction::new(
3581-
commitment_stats.tx,
3594+
commitment_data.stats.tx,
35823595
msg.signature,
35833596
msg.htlc_signatures.clone(),
35843597
&funding.get_holder_pubkeys().funding_pubkey,
35853598
funding.counterparty_funding_pubkey()
35863599
);
35873600

3588-
self.holder_signer.as_ref().validate_holder_commitment(&holder_commitment_tx, commitment_stats.outbound_htlc_preimages)
3601+
self.holder_signer.as_ref().validate_holder_commitment(&holder_commitment_tx, commitment_data.outbound_htlc_preimages)
35893602
.map_err(|_| ChannelError::close("Failed to validate our commitment".to_owned()))?;
35903603

35913604
Ok(LatestHolderCommitmentTXInfo {
@@ -3609,7 +3622,7 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider {
36093622
/// generated by the peer which proposed adding the HTLCs, and thus we need to understand both
36103623
/// which peer generated this transaction and "to whom" this transaction flows.
36113624
#[inline]
3612-
fn build_commitment_transaction<L: Deref>(&self, funding: &FundingScope, commitment_number: u64, per_commitment_point: &PublicKey, local: bool, generated_by_local: bool, logger: &L) -> CommitmentStats
3625+
fn build_commitment_transaction<L: Deref>(&self, funding: &FundingScope, commitment_number: u64, per_commitment_point: &PublicKey, local: bool, generated_by_local: bool, logger: &L) -> CommitmentData
36133626
where L::Target: Logger
36143627
{
36153628
let mut included_dust_htlcs: Vec<(HTLCOutputInCommitment, Option<&HTLCSource>)> = Vec::new();
@@ -3816,12 +3829,16 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider {
38163829
htlcs_included.sort_unstable_by_key(|h| h.0.transaction_output_index.unwrap());
38173830
htlcs_included.append(&mut included_dust_htlcs);
38183831

3819-
CommitmentStats {
3832+
let stats = CommitmentStats {
38203833
tx,
38213834
total_fee_sat,
3822-
htlcs_included,
38233835
local_balance_msat: value_to_self_msat,
38243836
remote_balance_msat: value_to_remote_msat,
3837+
};
3838+
3839+
CommitmentData {
3840+
stats,
3841+
htlcs_included,
38253842
inbound_htlc_preimages,
38263843
outbound_htlc_preimages,
38273844
}
@@ -4609,8 +4626,10 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider {
46094626
SP::Target: SignerProvider,
46104627
L::Target: Logger
46114628
{
4612-
let counterparty_initial_commitment_tx = self.build_commitment_transaction(
4613-
funding, self.cur_counterparty_commitment_transaction_number, &self.counterparty_cur_commitment_point.unwrap(), false, false, logger).tx;
4629+
let commitment_data = self.build_commitment_transaction(funding,
4630+
self.cur_counterparty_commitment_transaction_number,
4631+
&self.counterparty_cur_commitment_point.unwrap(), false, false, logger);
4632+
let counterparty_initial_commitment_tx = commitment_data.stats.tx;
46144633
match self.holder_signer {
46154634
// TODO (taproot|arik): move match into calling method for Taproot
46164635
ChannelSignerType::Ecdsa(ref ecdsa) => {
@@ -6323,9 +6342,11 @@ impl<SP: Deref> FundedChannel<SP> where
63236342
// Before proposing a feerate update, check that we can actually afford the new fee.
63246343
let dust_exposure_limiting_feerate = self.context.get_dust_exposure_limiting_feerate(&fee_estimator);
63256344
let htlc_stats = self.context.get_pending_htlc_stats(Some(feerate_per_kw), dust_exposure_limiting_feerate);
6326-
let commitment_stats = self.context.build_commitment_transaction(&self.funding, self.holder_commitment_point.transaction_number(), &self.holder_commitment_point.current_point(), true, true, logger);
6327-
let buffer_fee_msat = commit_tx_fee_sat(feerate_per_kw, commitment_stats.tx.htlcs().len() + htlc_stats.on_holder_tx_outbound_holding_cell_htlcs_count as usize + CONCURRENT_INBOUND_HTLC_FEE_BUFFER as usize, self.context.get_channel_type()) * 1000;
6328-
let holder_balance_msat = commitment_stats.local_balance_msat - htlc_stats.outbound_holding_cell_msat;
6345+
let commitment_data = self.context.build_commitment_transaction(&self.funding,
6346+
self.holder_commitment_point.transaction_number(),
6347+
&self.holder_commitment_point.current_point(), true, true, logger);
6348+
let buffer_fee_msat = commit_tx_fee_sat(feerate_per_kw, commitment_data.stats.tx.htlcs().len() + htlc_stats.on_holder_tx_outbound_holding_cell_htlcs_count as usize + CONCURRENT_INBOUND_HTLC_FEE_BUFFER as usize, self.context.get_channel_type()) * 1000;
6349+
let holder_balance_msat = commitment_data.stats.local_balance_msat - htlc_stats.outbound_holding_cell_msat;
63296350
if holder_balance_msat < buffer_fee_msat + self.funding.counterparty_selected_channel_reserve_satoshis.unwrap() * 1000 {
63306351
//TODO: auto-close after a number of failures?
63316352
log_debug!(logger, "Cannot afford to send new feerate at {}", feerate_per_kw);
@@ -6636,7 +6657,10 @@ impl<SP: Deref> FundedChannel<SP> where
66366657
self.holder_commitment_point.try_resolve_pending(&self.context.holder_signer, &self.context.secp_ctx, logger);
66376658
}
66386659
let funding_signed = if self.context.signer_pending_funding && !self.funding.is_outbound() {
6639-
let counterparty_initial_commitment_tx = self.context.build_commitment_transaction(&self.funding, self.context.cur_counterparty_commitment_transaction_number + 1, &self.context.counterparty_cur_commitment_point.unwrap(), false, false, logger).tx;
6660+
let commitment_data = self.context.build_commitment_transaction(&self.funding,
6661+
self.context.cur_counterparty_commitment_transaction_number + 1,
6662+
&self.context.counterparty_cur_commitment_point.unwrap(), false, false, logger);
6663+
let counterparty_initial_commitment_tx = commitment_data.stats.tx;
66406664
self.context.get_funding_signed_msg(&self.funding.channel_transaction_parameters, logger, counterparty_initial_commitment_tx)
66416665
} else { None };
66426666
// Provide a `channel_ready` message if we need to, but only if we're _not_ still pending
@@ -8709,8 +8733,10 @@ impl<SP: Deref> FundedChannel<SP> where
87098733
-> (Vec<(HTLCOutputInCommitment, Option<&HTLCSource>)>, CommitmentTransaction)
87108734
where L::Target: Logger
87118735
{
8712-
let commitment_stats = self.context.build_commitment_transaction(&self.funding, self.context.cur_counterparty_commitment_transaction_number, &self.context.counterparty_cur_commitment_point.unwrap(), false, true, logger);
8713-
let counterparty_commitment_tx = commitment_stats.tx;
8736+
let commitment_data = self.context.build_commitment_transaction(&self.funding,
8737+
self.context.cur_counterparty_commitment_transaction_number,
8738+
&self.context.counterparty_cur_commitment_point.unwrap(), false, true, logger);
8739+
let counterparty_commitment_tx = commitment_data.stats.tx;
87148740

87158741
#[cfg(any(test, fuzzing))]
87168742
{
@@ -8730,7 +8756,7 @@ impl<SP: Deref> FundedChannel<SP> where
87308756
}
87318757
}
87328758

8733-
(commitment_stats.htlcs_included, counterparty_commitment_tx)
8759+
(commitment_data.htlcs_included, counterparty_commitment_tx)
87348760
}
87358761

87368762
/// Only fails in case of signer rejection. Used for channel_reestablish commitment_signed
@@ -8740,8 +8766,10 @@ impl<SP: Deref> FundedChannel<SP> where
87408766
#[cfg(any(test, fuzzing))]
87418767
self.build_commitment_no_state_update(logger);
87428768

8743-
let commitment_stats = self.context.build_commitment_transaction(&self.funding, self.context.cur_counterparty_commitment_transaction_number, &self.context.counterparty_cur_commitment_point.unwrap(), false, true, logger);
8744-
let counterparty_commitment_txid = commitment_stats.tx.trust().txid();
8769+
let commitment_data = self.context.build_commitment_transaction(&self.funding,
8770+
self.context.cur_counterparty_commitment_transaction_number,
8771+
&self.context.counterparty_cur_commitment_point.unwrap(), false, true, logger);
8772+
let counterparty_commitment_tx = commitment_data.stats.tx;
87458773

87468774
match &self.context.holder_signer {
87478775
ChannelSignerType::Ecdsa(ecdsa) => {
@@ -8750,24 +8778,25 @@ impl<SP: Deref> FundedChannel<SP> where
87508778
{
87518779
let res = ecdsa.sign_counterparty_commitment(
87528780
&self.funding.channel_transaction_parameters,
8753-
&commitment_stats.tx,
8754-
commitment_stats.inbound_htlc_preimages,
8755-
commitment_stats.outbound_htlc_preimages,
8781+
&counterparty_commitment_tx,
8782+
commitment_data.inbound_htlc_preimages,
8783+
commitment_data.outbound_htlc_preimages,
87568784
&self.context.secp_ctx,
87578785
).map_err(|_| ChannelError::Ignore("Failed to get signatures for new commitment_signed".to_owned()))?;
87588786
signature = res.0;
87598787
htlc_signatures = res.1;
87608788

8789+
let trusted_tx = counterparty_commitment_tx.trust();
87618790
log_trace!(logger, "Signed remote commitment tx {} (txid {}) with redeemscript {} -> {} in channel {}",
8762-
encode::serialize_hex(&commitment_stats.tx.trust().built_transaction().transaction),
8763-
&counterparty_commitment_txid, encode::serialize_hex(&self.funding.get_funding_redeemscript()),
8791+
encode::serialize_hex(&trusted_tx.built_transaction().transaction),
8792+
&trusted_tx.txid(), encode::serialize_hex(&self.funding.get_funding_redeemscript()),
87648793
log_bytes!(signature.serialize_compact()[..]), &self.context.channel_id());
87658794

8766-
let counterparty_keys = commitment_stats.tx.trust().keys();
8767-
debug_assert_eq!(htlc_signatures.len(), commitment_stats.tx.htlcs().len());
8768-
for (ref htlc_sig, ref htlc) in htlc_signatures.iter().zip(commitment_stats.tx.htlcs()) {
8795+
let counterparty_keys = trusted_tx.keys();
8796+
debug_assert_eq!(htlc_signatures.len(), trusted_tx.htlcs().len());
8797+
for (ref htlc_sig, ref htlc) in htlc_signatures.iter().zip(trusted_tx.htlcs()) {
87698798
log_trace!(logger, "Signed remote HTLC tx {} with redeemscript {} with pubkey {} -> {} in channel {}",
8770-
encode::serialize_hex(&chan_utils::build_htlc_transaction(&counterparty_commitment_txid, commitment_stats.tx.feerate_per_kw(), self.funding.get_holder_selected_contest_delay(), htlc, &self.context.channel_type, &counterparty_keys.broadcaster_delayed_payment_key, &counterparty_keys.revocation_key)),
8799+
encode::serialize_hex(&chan_utils::build_htlc_transaction(&trusted_tx.txid(), trusted_tx.feerate_per_kw(), self.funding.get_holder_selected_contest_delay(), htlc, &self.context.channel_type, &counterparty_keys.broadcaster_delayed_payment_key, &counterparty_keys.revocation_key)),
87718800
encode::serialize_hex(&chan_utils::get_htlc_redeemscript(&htlc, &self.context.channel_type, &counterparty_keys)),
87728801
log_bytes!(counterparty_keys.broadcaster_htlc_key.to_public_key().serialize()),
87738802
log_bytes!(htlc_sig.serialize_compact()[..]), &self.context.channel_id());
@@ -9221,7 +9250,10 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
92219250

92229251
/// Only allowed after [`FundingScope::channel_transaction_parameters`] is set.
92239252
fn get_funding_created_msg<L: Deref>(&mut self, logger: &L) -> Option<msgs::FundingCreated> where L::Target: Logger {
9224-
let counterparty_initial_commitment_tx = self.context.build_commitment_transaction(&self.funding, self.context.cur_counterparty_commitment_transaction_number, &self.context.counterparty_cur_commitment_point.unwrap(), false, false, logger).tx;
9253+
let commitment_data = self.context.build_commitment_transaction(&self.funding,
9254+
self.context.cur_counterparty_commitment_transaction_number,
9255+
&self.context.counterparty_cur_commitment_point.unwrap(), false, false, logger);
9256+
let counterparty_initial_commitment_tx = commitment_data.stats.tx;
92259257
let signature = match &self.context.holder_signer {
92269258
// TODO (taproot|arik): move match into calling method for Taproot
92279259
ChannelSignerType::Ecdsa(ecdsa) => {
@@ -11872,8 +11904,9 @@ mod tests {
1187211904
( $counterparty_sig_hex: expr, $sig_hex: expr, $tx_hex: expr, $opt_anchors: expr, {
1187311905
$( { $htlc_idx: expr, $counterparty_htlc_sig_hex: expr, $htlc_sig_hex: expr, $htlc_tx_hex: expr } ), *
1187411906
} ) => { {
11875-
let commitment_stats = chan.context.build_commitment_transaction(&chan.funding, 0xffffffffffff - 42, &per_commitment_point, true, false, &logger);
11876-
let commitment_tx = commitment_stats.tx;
11907+
let commitment_data = chan.context.build_commitment_transaction(&chan.funding,
11908+
0xffffffffffff - 42, &per_commitment_point, true, false, &logger);
11909+
let commitment_tx = commitment_data.stats.tx;
1187711910
let trusted_tx = commitment_tx.trust();
1187811911
let unsigned_tx = trusted_tx.built_transaction();
1187911912
let redeemscript = chan.funding.get_funding_redeemscript();

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