cleanup

Author: devrandom

lightning/src/chain/keysinterface.rs

@@ -196,11 +196,15 @@ impl Readable for SpendableOutputDescriptor {
 // ChannelMonitors instead of expecting to clone the one out of the Channel into the monitors.
 pub trait ChannelKeys : Send+Clone {
 	/// Gets the per-commitment point for a specific commitment number
-	/// Note that the commitment number starts at (1 << 48) - 1 and counts backwards
+	///
+	/// Note that the commitment number starts at (1 << 48) - 1 and counts backwards.
 	fn get_per_commitment_point<T: secp256k1::Signing + secp256k1::Verification>(&self, idx: u64, secp_ctx: &Secp256k1<T>) -> PublicKey;
 	/// Gets the commitment seed for a specific commitment number, thereby revoking the commitment
-	/// Note that the commitment number starts at (1 << 48) - 1 and counts backwards
-	fn revoke_commitment(&self, idx: u64) -> [u8; 32];
+	///
+	/// After this is called, it is an error to try to sign the relevant local commitment transaction.
+	/// May be called more than once (e.g. if re-establishing the channel).
+	/// Note that the commitment number starts at (1 << 48) - 1 and counts backwards.
+	fn get_revoke_commitment_secret(&self, idx: u64) -> [u8; 32];
 	/// Gets the local channel public keys and basepoints
 	fn pubkeys(&self) -> &ChannelPublicKeys;
 	/// Gets arbitrary identifiers describing the set of keys which are provided back to you in
@@ -220,6 +224,7 @@ pub trait ChannelKeys : Send+Clone {
 	/// Create a signature for a local commitment transaction. This will only ever be called with
 	/// the same local_commitment_tx (or a copy thereof), though there are currently no guarantees
 	/// that it will not be called multiple times.
+	/// The commitment must not have been revoked.
 	//
 	// TODO: Document the things someone using this interface should enforce before signing.
 	// TODO: Add more input vars to enable better checking (preferably removing commitment_tx and
@@ -413,7 +418,7 @@ impl ChannelKeys for InMemoryChannelKeys {
 		PublicKey::from_secret_key(secp_ctx, &commitment_secret)
 	}
 
-	fn revoke_commitment(&self, idx: u64) -> [u8; 32] {
+	fn get_revoke_commitment_secret(&self, idx: u64) -> [u8; 32] {
 		chan_utils::build_commitment_secret(&self.commitment_seed, idx)
 	}
 

lightning/src/ln/chan_utils.rs

@@ -497,8 +497,8 @@ pub fn build_htlc_transaction(prev_hash: &Txid, feerate_per_kw: u32, to_self_del
 
 #[derive(Clone)]
 /// We use this to track local commitment transactions and put off signing them until we are ready
-/// to broadcast. Eventually this will require a signer which is possibly external, but for now we
-/// just pass in the SecretKeys required.
+/// to broadcast. This class can be used inside a signer implementation to generate a signature
+/// given the relevant secret key.
 pub struct LocalCommitmentTransaction {
 	// TODO: We should migrate away from providing the transaction, instead providing enough to
 	// allow the ChannelKeys to construct it from scratch. Luckily we already have HTLC data here,

lightning/src/ln/channel.rs

@@ -2014,7 +2014,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 		}
 
 		let next_per_commitment_point = self.local_keys.get_per_commitment_point(self.cur_local_commitment_transaction_number - 1, &self.secp_ctx);
-		let per_commitment_secret = self.local_keys.revoke_commitment(self.cur_local_commitment_transaction_number + 1);
+		let per_commitment_secret = self.local_keys.get_revoke_commitment_secret(self.cur_local_commitment_transaction_number + 1);
 
 		// Update state now that we've passed all the can-fail calls...
 		let mut need_our_commitment = false;
@@ -2652,7 +2652,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 
 	fn get_last_revoke_and_ack(&self) -> msgs::RevokeAndACK {
 		let next_per_commitment_point = self.local_keys.get_per_commitment_point(self.cur_local_commitment_transaction_number, &self.secp_ctx);
-		let per_commitment_secret = self.local_keys.revoke_commitment(self.cur_local_commitment_transaction_number + 2);
+		let per_commitment_secret = self.local_keys.get_revoke_commitment_secret(self.cur_local_commitment_transaction_number + 2);
 		msgs::RevokeAndACK {
 			channel_id: self.channel_id,
 			per_commitment_secret,

lightning/src/ln/functional_tests.rs

@@ -1609,15 +1609,15 @@ fn test_fee_spike_violation_fails_htlc() {
 		let chan_keys = local_chan.get_local_keys();
 		let pubkeys = chan_keys.pubkeys();
 		(pubkeys.revocation_basepoint, pubkeys.htlc_basepoint, pubkeys.payment_point,
-		 chan_keys.revoke_commitment(INITIAL_COMMITMENT_NUMBER), chan_keys.revoke_commitment(INITIAL_COMMITMENT_NUMBER - 2))
+		 chan_keys.get_revoke_commitment_secret(INITIAL_COMMITMENT_NUMBER), chan_keys.get_revoke_commitment_secret(INITIAL_COMMITMENT_NUMBER - 2))
 	};
 	let (remote_delayed_payment_basepoint, remote_htlc_basepoint, remote_payment_point, remote_secret1) = {
 		let chan_lock = nodes[1].node.channel_state.lock().unwrap();
 		let remote_chan = chan_lock.by_id.get(&chan.2).unwrap();
 		let chan_keys = remote_chan.get_local_keys();
 		let pubkeys = chan_keys.pubkeys();
 		(pubkeys.delayed_payment_basepoint, pubkeys.htlc_basepoint, pubkeys.payment_point,
-		 chan_keys.revoke_commitment(INITIAL_COMMITMENT_NUMBER - 1))
+		 chan_keys.get_revoke_commitment_secret(INITIAL_COMMITMENT_NUMBER - 1))
 	};
 
 	// Assemble the set of keys we can use for signatures for our commitment_signed message.
@@ -8129,8 +8129,8 @@ fn test_counterparty_raa_skip_no_crash() {
 	let local_keys = &guard.by_id.get_mut(&channel_id).unwrap().local_keys;
 	const INITIAL_COMMITMENT_NUMBER: u64 = (1 << 48) - 1;
 	let next_per_commitment_point = PublicKey::from_secret_key(&Secp256k1::new(),
-		&SecretKey::from_slice(&local_keys.revoke_commitment(INITIAL_COMMITMENT_NUMBER - 2)).unwrap());
-	let per_commitment_secret = local_keys.revoke_commitment(INITIAL_COMMITMENT_NUMBER);
+		&SecretKey::from_slice(&local_keys.get_revoke_commitment_secret(INITIAL_COMMITMENT_NUMBER - 2)).unwrap());
+	let per_commitment_secret = local_keys.get_revoke_commitment_secret(INITIAL_COMMITMENT_NUMBER);
 
 	nodes[1].node.handle_revoke_and_ack(&nodes[0].node.get_our_node_id(),
 		&msgs::RevokeAndACK { channel_id, per_commitment_secret, next_per_commitment_point });

lightning/src/util/enforcing_trait_impls.rs

@@ -52,7 +52,7 @@ impl ChannelKeys for EnforcingChannelKeys {
 		self.inner.get_per_commitment_point(idx, secp_ctx)
 	}
 
-	fn revoke_commitment(&self, idx: u64) -> [u8; 32] { self.inner.revoke_commitment(idx) }
+	fn get_revoke_commitment_secret(&self, idx: u64) -> [u8; 32] { self.inner.get_revoke_commitment_secret(idx) }
 	fn pubkeys(&self) -> &ChannelPublicKeys { self.inner.pubkeys() }
 	fn key_derivation_params(&self) -> (u64, u64) { self.inner.key_derivation_params() }