Improve the API of the derived fields in CommitmentTransaction

Author: devrandom

lightning/src/chain/channelmonitor.rs

@@ -969,23 +969,23 @@ impl<ChanSigner: ChannelKeys> ChannelMonitor<ChanSigner> {
 
 		let secp_ctx = Secp256k1::new();
 
-		let txid = initial_holder_commitment_tx.untrusted_txid();
-
 		// block for Rust 1.34 compat
 		let (holder_commitment_tx, current_holder_commitment_number) = {
-			let commitment_tx = &initial_holder_commitment_tx.inner;
-			let tx_keys = commitment_tx.untrusted_key_derivation();
+			let trusted_tx = initial_holder_commitment_tx.trust();
+			let txid = trusted_tx.txid();
+
+			let tx_keys = trusted_tx.keys();
 			let holder_commitment_tx = HolderSignedTx {
 				txid,
 				revocation_key: tx_keys.revocation_key,
 				a_htlc_key: tx_keys.broadcaster_htlc_key,
 				b_htlc_key: tx_keys.countersignatory_htlc_key,
 				delayed_payment_key: tx_keys.broadcaster_delayed_payment_key,
 				per_commitment_point: tx_keys.per_commitment_point,
-				feerate_per_kw: commitment_tx.feerate_per_kw(),
+				feerate_per_kw: trusted_tx.feerate_per_kw(),
 				htlc_outputs: Vec::new(), // There are never any HTLCs in the initial commitment transactions
 			};
-			(holder_commitment_tx, commitment_tx.commitment_number())
+			(holder_commitment_tx, trusted_tx.commitment_number())
 		};
 		onchain_tx_handler.provide_latest_holder_tx(initial_holder_commitment_tx);
 
@@ -1143,21 +1143,21 @@ impl<ChanSigner: ChannelKeys> ChannelMonitor<ChanSigner> {
 	/// up-to-date as our holder commitment transaction is updated.
 	/// Panics if set_on_holder_tx_csv has never been called.
 	fn provide_latest_holder_commitment_tx(&mut self, holder_commitment_tx: HolderCommitmentTransaction, htlc_outputs: Vec<(HTLCOutputInCommitment, Option<Signature>, Option<HTLCSource>)>) -> Result<(), MonitorUpdateError> {
-		let txid = holder_commitment_tx.untrusted_txid();
-
 		// block for Rust 1.34 compat
 		let mut new_holder_commitment_tx = {
-			let commitment_tx = &holder_commitment_tx.inner;
-			let tx_keys = &commitment_tx.untrusted_key_derivation();
-			self.current_holder_commitment_number = commitment_tx.commitment_number();
+			let trusted_tx = holder_commitment_tx.trust();
+			let txid = trusted_tx.txid();
+
+			let tx_keys = trusted_tx.keys();
+			self.current_holder_commitment_number = trusted_tx.commitment_number();
 			HolderSignedTx {
 				txid,
 				revocation_key: tx_keys.revocation_key,
 				a_htlc_key: tx_keys.broadcaster_htlc_key,
 				b_htlc_key: tx_keys.countersignatory_htlc_key,
 				delayed_payment_key: tx_keys.broadcaster_delayed_payment_key,
 				per_commitment_point: tx_keys.per_commitment_point,
-				feerate_per_kw: commitment_tx.feerate_per_kw(),
+				feerate_per_kw: trusted_tx.feerate_per_kw(),
 				htlc_outputs,
 			}
 		};

lightning/src/chain/keysinterface.rs

@@ -463,15 +463,16 @@ impl ChannelKeys for InMemoryChannelKeys {
 	fn key_derivation_params(&self) -> (u64, u64) { self.key_derivation_params }
 
 	fn sign_counterparty_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, commitment_tx: &CommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<(Signature, Vec<Signature>), ()> {
-		let keys = commitment_tx.untrusted_key_derivation();
+		let trusted_tx = commitment_tx.trust();
+		let keys = trusted_tx.keys();
 
 		let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
 		let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
 
-		let built_tx = commitment_tx.untrusted_built_transaction();
+		let built_tx = trusted_tx.built_transaction();
 		let commitment_sig = built_tx.sign(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx);
 
-		let commitment_txid = commitment_tx.untrusted_txid();
+		let commitment_txid = trusted_tx.txid();
 
 		let mut htlc_sigs = Vec::with_capacity(commitment_tx.htlcs().len());
 		for htlc in commitment_tx.htlcs() {
@@ -491,8 +492,8 @@ impl ChannelKeys for InMemoryChannelKeys {
 	fn sign_holder_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<(Signature, Vec<Signature>), ()> {
 		let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
 		let funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
-
-		let built_tx = commitment_tx.inner.untrusted_built_transaction();
+		let trusted_tx = commitment_tx.trust();
+		let built_tx = trusted_tx.built_transaction();
 		let sig = built_tx.sign(&self.funding_key, &funding_redeemscript, self.channel_value_satoshis, secp_ctx);
 		let htlc_sigs_o = self.sign_holder_commitment_htlc_transactions(&commitment_tx, secp_ctx)?;
 		let htlc_sigs = htlc_sigs_o.iter().map(|o| o.unwrap()).collect();
@@ -504,15 +505,17 @@ impl ChannelKeys for InMemoryChannelKeys {
 	fn unsafe_sign_holder_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, holder_commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
 		let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
 		let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
+		let trusted_tx = holder_commitment_tx.trust();
 
-		let built_tx = holder_commitment_tx.inner.untrusted_built_transaction();
+		let built_tx = trusted_tx.built_transaction();
 		Ok(built_tx.sign(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx))
 	}
 
 	fn sign_holder_commitment_htlc_transactions<T: secp256k1::Signing + secp256k1::Verification>(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Vec<Option<Signature>>, ()> {
 		let channel_parameters = self.make_channel_parameters();
 		let channel_parameters = channel_parameters.as_holder_broadcastable();
-		commitment_tx.inner.get_htlc_sigs(&self.htlc_base_key, &channel_parameters, secp_ctx)
+		let trusted_tx = commitment_tx.trust();
+		trusted_tx.get_htlc_sigs(&self.htlc_base_key, &channel_parameters, secp_ctx)
 	}
 
 	fn sign_justice_transaction<T: secp256k1::Signing + secp256k1::Verification>(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, htlc: &Option<HTLCOutputInCommitment>, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {