Add funding redeem script to ChannelDetails and ChannelPending event

fuzz/src/router.rs

@@ -229,6 +229,7 @@ pub fn do_test<Out: test_logger::Output>(data: &[u8], out: Out) {
 								txid: bitcoin::Txid::from_slice(&[0; 32]).unwrap(),
 								index: 0,
 							}),
+							funding_redeem_script: None,
 							channel_type: None,
 							short_channel_id: Some(scid),
 							inbound_scid_alias: None,

lightning/src/events/mod.rs

@@ -1413,6 +1413,10 @@ pub enum Event {
 		///
 		/// Will be `None` for channels created prior to LDK version 0.0.122.
 		channel_type: Option<ChannelTypeFeatures>,
+		/// The witness script that is used to lock the channel's funding output to commitment transactions.
+		///
+		/// This field will be `None` for objects serialized with LDK versions prior to 0.2.0.
+		funding_redeem_script: Option<ScriptBuf>,
 	},
 	/// Used to indicate that a channel with the given `channel_id` is ready to be used. This event
 	/// is emitted when
@@ -1532,6 +1536,8 @@ pub enum Event {
 		/// The features that this channel will operate with. Currently, these will be the same
 		/// features that the channel was opened with, but in the future splices may change them.
 		channel_type: ChannelTypeFeatures,
+		/// The witness script that is used to lock the channel's funding output to commitment transactions.
+		new_funding_redeem_script: ScriptBuf,
 	},
 	/// Used to indicate that a splice for the given `channel_id` has failed.
 	///
@@ -2234,6 +2240,7 @@ impl Writeable for Event {
 				ref counterparty_node_id,
 				ref funding_txo,
 				ref channel_type,
+				ref funding_redeem_script,
 			} => {
 				31u8.write(writer)?;
 				write_tlv_fields!(writer, {
@@ -2243,6 +2250,7 @@ impl Writeable for Event {
 					(4, former_temporary_channel_id, required),
 					(6, counterparty_node_id, required),
 					(8, funding_txo, required),
+					(9, funding_redeem_script, option),
 				});
 			},
 			&Event::ConnectionNeeded { .. } => {
@@ -2307,6 +2315,7 @@ impl Writeable for Event {
 				ref counterparty_node_id,
 				ref new_funding_txo,
 				ref channel_type,
+				ref new_funding_redeem_script,
 			} => {
 				50u8.write(writer)?;
 				write_tlv_fields!(writer, {
@@ -2315,6 +2324,7 @@ impl Writeable for Event {
 					(5, user_channel_id, required),
 					(7, counterparty_node_id, required),
 					(9, new_funding_txo, required),
+					(11, new_funding_redeem_script, required),
 				});
 			},
 			&Event::SpliceFailed {
@@ -2815,13 +2825,15 @@ impl MaybeReadable for Event {
 					let mut counterparty_node_id = RequiredWrapper(None);
 					let mut funding_txo = RequiredWrapper(None);
 					let mut channel_type = None;
+					let mut funding_redeem_script = None;
 					read_tlv_fields!(reader, {
 						(0, channel_id, required),
 						(1, channel_type, option),
 						(2, user_channel_id, required),
 						(4, former_temporary_channel_id, required),
 						(6, counterparty_node_id, required),
 						(8, funding_txo, required),
+						(9, funding_redeem_script, option),
 					});
 
 					Ok(Some(Event::ChannelPending {
@@ -2831,6 +2843,7 @@ impl MaybeReadable for Event {
 						counterparty_node_id: counterparty_node_id.0.unwrap(),
 						funding_txo: funding_txo.0.unwrap(),
 						channel_type,
+						funding_redeem_script,
 					}))
 				};
 				f()
@@ -2927,6 +2940,7 @@ impl MaybeReadable for Event {
 						(5, user_channel_id, required),
 						(7, counterparty_node_id, required),
 						(9, new_funding_txo, required),
+						(11, new_funding_redeem_script, required),
 					});
 
 					Ok(Some(Event::SplicePending {
@@ -2935,6 +2949,7 @@ impl MaybeReadable for Event {
 						counterparty_node_id: counterparty_node_id.0.unwrap(),
 						new_funding_txo: new_funding_txo.0.unwrap(),
 						channel_type: channel_type.0.unwrap(),
+						new_funding_redeem_script: new_funding_redeem_script.0.unwrap(),
 					}))
 				};
 				f()

lightning/src/ln/chan_utils.rs

@@ -1121,12 +1121,17 @@ impl ChannelTransactionParameters {
 		}
 	}
 
-	#[rustfmt::skip]
 	pub(crate) fn make_funding_redeemscript(&self) -> ScriptBuf {
-		make_funding_redeemscript(
-			&self.holder_pubkeys.funding_pubkey,
-			&self.counterparty_parameters.as_ref().unwrap().pubkeys.funding_pubkey
-		)
+		self.make_funding_redeemscript_opt().unwrap()
+	}
+
+	pub(crate) fn make_funding_redeemscript_opt(&self) -> Option<ScriptBuf> {
+		self.counterparty_parameters.as_ref().map(|p| {
+			make_funding_redeemscript(
+				&self.holder_pubkeys.funding_pubkey,
+				&p.pubkeys.funding_pubkey,
+			)
+		})
 	}
 
 	/// Returns the counterparty's pubkeys.

lightning/src/ln/channel.rs

@@ -6862,6 +6862,9 @@ pub struct SpliceFundingNegotiated {
 
 	/// The features that this channel will operate with.
 	pub channel_type: ChannelTypeFeatures,
+
+	/// The redeem script of the funding output.
+	pub funding_redeem_script: ScriptBuf,
 }
 
 /// Information about a splice funding negotiation that has failed.
@@ -8939,12 +8942,14 @@ where
 				let funding_txo =
 					funding.get_funding_txo().expect("funding outpoint should be set");
 				let channel_type = funding.get_channel_type().clone();
+				let funding_redeem_script = funding.get_funding_redeemscript();
 
 				pending_splice.negotiated_candidates.push(funding);
 
 				let splice_negotiated = SpliceFundingNegotiated {
 					funding_txo: funding_txo.into_bitcoin_outpoint(),
 					channel_type,
+					funding_redeem_script,
 				};
 
 				let splice_locked = pending_splice.check_get_splice_locked(

lightning/src/ln/channel_state.rs

@@ -450,6 +450,10 @@ pub struct ChannelDetails {
 	///
 	/// This field is empty for objects serialized with LDK versions prior to 0.0.122.
 	pub pending_outbound_htlcs: Vec<OutboundHTLCDetails>,
+	/// The witness script that is used to lock the channel's funding output to commitment transactions.
+	///
+	/// This field will be `None` for objects serialized with LDK versions prior to 0.2.0.
+	pub funding_redeem_script: Option<bitcoin::ScriptBuf>,
 }
 
 impl ChannelDetails {
@@ -475,6 +479,21 @@ impl ChannelDetails {
 		self.short_channel_id.or(self.outbound_scid_alias)
 	}
 
+	/// Gets the funding output for this channel, if available.
+	///
+	/// During a splice, the funding output will change and this value will be updated
+	/// after the splice transaction has reached sufficient confirmations and we've
+	/// exchanged `splice_locked` messages.
+	pub fn get_funding_output(&self) -> Option<bitcoin::TxOut> {
+		match self.funding_redeem_script.as_ref() {
+			None => None,
+			Some(redeem_script) => Some(bitcoin::TxOut {
+				value: bitcoin::Amount::from_sat(self.channel_value_satoshis),
+				script_pubkey: redeem_script.to_p2wsh(),
+			}),
+		}
+	}
+
 	pub(super) fn from_channel<SP: Deref, F: Deref>(
 		channel: &Channel<SP>, best_block_height: u32, latest_features: InitFeatures,
 		fee_estimator: &LowerBoundedFeeEstimator<F>,
@@ -509,6 +528,9 @@ impl ChannelDetails {
 				outbound_htlc_maximum_msat: context.get_counterparty_htlc_maximum_msat(funding),
 			},
 			funding_txo: funding.get_funding_txo(),
+			funding_redeem_script: funding
+				.channel_transaction_parameters
+				.make_funding_redeemscript_opt(),
 			// Note that accept_channel (or open_channel) is always the first message, so
 			// `have_received_message` indicates that type negotiation has completed.
 			channel_type: if context.have_received_message() {
@@ -583,6 +605,7 @@ impl_writeable_tlv_based!(ChannelDetails, {
 	(41, channel_shutdown_state, option),
 	(43, pending_inbound_htlcs, optional_vec),
 	(45, pending_outbound_htlcs, optional_vec),
+	(47, funding_redeem_script, option),
 	(_unused, user_channel_id, (static_value,
 		_user_channel_id_low.unwrap_or(0) as u128 | ((_user_channel_id_high.unwrap_or(0) as u128) << 64)
 	)),
@@ -627,6 +650,7 @@ mod tests {
 	use crate::{
 		chain::transaction::OutPoint,
 		ln::{
+			chan_utils::make_funding_redeemscript,
 			channel_state::{
 				InboundHTLCDetails, InboundHTLCStateDetails, OutboundHTLCDetails,
 				OutboundHTLCStateDetails,
@@ -658,6 +682,10 @@ mod tests {
 				txid: bitcoin::Txid::from_slice(&[0; 32]).unwrap(),
 				index: 1,
 			}),
+			funding_redeem_script: Some(make_funding_redeemscript(
+				&PublicKey::from_slice(&[2; 33]).unwrap(),
+				&PublicKey::from_slice(&[2; 33]).unwrap(),
+			)),
 			channel_type: None,
 			short_channel_id: None,
 			outbound_scid_alias: None,

lightning/src/ln/channelmanager.rs

@@ -3303,6 +3303,8 @@ macro_rules! emit_channel_pending_event {
 	($locked_events: expr, $channel: expr) => {
 		if $channel.context.should_emit_channel_pending_event() {
 			let funding_txo = $channel.funding.get_funding_txo().unwrap();
+			let funding_redeem_script =
+				Some($channel.funding.channel_transaction_parameters.make_funding_redeemscript());
 			$locked_events.push_back((
 				events::Event::ChannelPending {
 					channel_id: $channel.context.channel_id(),
@@ -3311,6 +3313,7 @@ macro_rules! emit_channel_pending_event {
 					user_channel_id: $channel.context.get_user_id(),
 					funding_txo: funding_txo.into_bitcoin_outpoint(),
 					channel_type: Some($channel.funding.get_channel_type().clone()),
+					funding_redeem_script,
 				},
 				None,
 			));
@@ -6486,6 +6489,8 @@ where
 											user_channel_id: chan.context.get_user_id(),
 											new_funding_txo: splice_negotiated.funding_txo,
 											channel_type: splice_negotiated.channel_type,
+											new_funding_redeem_script: splice_negotiated
+												.funding_redeem_script,
 										},
 										None,
 									));
@@ -9729,6 +9734,7 @@ This indicates a bug inside LDK. Please report this error at https://github.com/
 									user_channel_id: channel.context.get_user_id(),
 									new_funding_txo: splice_negotiated.funding_txo,
 									channel_type: splice_negotiated.channel_type,
+									new_funding_redeem_script: splice_negotiated.funding_redeem_script,
 								},
 								None,
 							));
@@ -10798,6 +10804,7 @@ This indicates a bug inside LDK. Please report this error at https://github.com/
 									user_channel_id: chan.context.get_user_id(),
 									new_funding_txo: splice_negotiated.funding_txo,
 									channel_type: splice_negotiated.channel_type,
+									new_funding_redeem_script: splice_negotiated.funding_redeem_script,
 								},
 								None,
 							));

lightning/src/routing/router.rs

@@ -3926,6 +3926,7 @@ mod tests {
 	use crate::blinded_path::BlindedHop;
 	use crate::chain::transaction::OutPoint;
 	use crate::crypto::chacha20::ChaCha20;
+	use crate::ln::chan_utils::make_funding_redeemscript;
 	use crate::ln::channel_state::{ChannelCounterparty, ChannelDetails, ChannelShutdownState};
 	use crate::ln::channelmanager;
 	use crate::ln::msgs::{UnsignedChannelUpdate, MAX_VALUE_MSAT};
@@ -3984,6 +3985,10 @@ mod tests {
 				outbound_htlc_maximum_msat: None,
 			},
 			funding_txo: Some(OutPoint { txid: bitcoin::Txid::from_slice(&[0; 32]).unwrap(), index: 0 }),
+			funding_redeem_script: Some(make_funding_redeemscript(
+				&PublicKey::from_slice(&[2; 33]).unwrap(),
+				&PublicKey::from_slice(&[2; 33]).unwrap(),
+			)),
 			channel_type: None,
 			short_channel_id,
 			outbound_scid_alias: None,
@@ -9384,6 +9389,7 @@ pub(crate) mod bench_utils {
 	use std::io::Read;
 
 	use crate::chain::transaction::OutPoint;
+	use crate::ln::chan_utils::make_funding_redeemscript;
 	use crate::ln::channel_state::{ChannelCounterparty, ChannelShutdownState};
 	use crate::ln::channelmanager;
 	use crate::ln::types::ChannelId;
@@ -9479,6 +9485,10 @@ pub(crate) mod bench_utils {
 			funding_txo: Some(OutPoint {
 				txid: bitcoin::Txid::from_slice(&[0; 32]).unwrap(), index: 0
 			}),
+			funding_redeem_script: Some(make_funding_redeemscript(
+				&PublicKey::from_slice(&[2; 33]).unwrap(),
+				&PublicKey::from_slice(&[2; 33]).unwrap(),
+			)),
 			channel_type: None,
 			short_channel_id: Some(1),
 			inbound_scid_alias: None,