Update the RevokeAndACK message for Taproot support.

Author: arik-so

lightning/src/ln/channel.rs

@@ -3910,6 +3910,8 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
 			channel_id: self.channel_id,
 			per_commitment_secret,
 			next_per_commitment_point,
+			#[cfg(taproot)]
+			next_local_nonce: None,
 		}
 	}
 

lightning/src/ln/functional_tests.rs

@@ -1470,7 +1470,9 @@ fn test_fee_spike_violation_fails_htlc() {
 	let raa_msg = msgs::RevokeAndACK {
 		channel_id: chan.2,
 		per_commitment_secret: local_secret,
-		next_per_commitment_point: next_local_point
+		next_per_commitment_point: next_local_point,
+		#[cfg(taproot)]
+		next_local_nonce: None,
 	};
 	nodes[1].node.handle_revoke_and_ack(&nodes[0].node.get_our_node_id(), &raa_msg);
 
@@ -7495,7 +7497,13 @@ fn test_counterparty_raa_skip_no_crash() {
 	}
 
 	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 });
+		&msgs::RevokeAndACK {
+			channel_id,
+			per_commitment_secret,
+			next_per_commitment_point,
+			#[cfg(taproot)]
+			next_local_nonce: None,
+		});
 	assert_eq!(check_closed_broadcast!(nodes[1], true).unwrap().data, "Received an unexpected revoke_and_ack");
 	check_added_monitors!(nodes[1], 1);
 	check_closed_event!(nodes[1], 1, ClosureReason::ProcessingError { err: "Received an unexpected revoke_and_ack".to_string() });

lightning/src/ln/msgs.rs

@@ -442,6 +442,9 @@ pub struct RevokeAndACK {
 	pub per_commitment_secret: [u8; 32],
 	/// The next sender-broadcast commitment transaction's per-commitment point
 	pub next_per_commitment_point: PublicKey,
+	#[cfg(taproot)]
+	/// Musig nonce the recipient should use in their next commitment signature message
+	pub next_local_nonce: Option<musig2::types::PublicNonce>
 }
 
 /// An [`update_fee`] message to be sent to or received from a peer
@@ -1518,12 +1521,22 @@ impl_writeable_msg!(OpenChannel, {
 	(1, channel_type, option),
 });
 
+#[cfg(not(taproot))]
 impl_writeable_msg!(RevokeAndACK, {
 	channel_id,
 	per_commitment_secret,
 	next_per_commitment_point
 }, {});
 
+#[cfg(taproot)]
+impl_writeable_msg!(RevokeAndACK, {
+	channel_id,
+	per_commitment_secret,
+	next_per_commitment_point
+}, {
+	(4, next_local_nonce, option)
+});
+
 impl_writeable_msg!(Shutdown, {
 	channel_id,
 	scriptpubkey
@@ -2753,6 +2766,8 @@ mod tests {
 			channel_id: [2; 32],
 			per_commitment_secret: [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
 			next_per_commitment_point: pubkey_1,
+			#[cfg(taproot)]
+			next_local_nonce: None,
 		};
 		let encoded_value = raa.encode();
 		let target_value = hex::decode("02020202020202020202020202020202020202020202020202020202020202020101010101010101010101010101010101010101010101010101010101010101031b84c5567b126440995d3ed5aaba0565d71e1834604819ff9c17f5e9d5dd078f").unwrap();