Enable spliting lightning channel

fuzz/src/chanmon_consistency.rs

@@ -166,6 +166,10 @@ impl chain::Watch<EnforcingSigner> for TestChainMonitor {
 	fn release_pending_monitor_events(&self) -> Vec<(OutPoint, Vec<MonitorEvent>, Option<PublicKey>)> {
 		return self.chain_monitor.release_pending_monitor_events();
 	}
+
+	fn update_channel_funding_txo(&self, old_funding_txo: OutPoint, new_funding_txo: OutPoint, channel_value_satoshis: u64) -> ChannelMonitorUpdateStatus {
+		todo!()
+	}
 }
 
 struct KeyProvider {
@@ -306,6 +310,7 @@ fn check_api_err(api_err: APIError, sendable_bounds_violated: bool) {
 			// We can (obviously) temp-fail a monitor update
 		},
 		APIError::IncompatibleShutdownScript { .. } => panic!("Cannot send an incompatible shutdown script"),
+		APIError::ExternalError { .. } => panic!("We don't produce external errors in fuzz!"),
 	}
 }
 #[inline]

fuzz/src/router.rs

@@ -271,6 +271,11 @@ pub fn do_test<Out: test_logger::Output>(data: &[u8], out: Out) {
 								config: None,
 								feerate_sat_per_1000_weight: None,
 								channel_shutdown_state: Some(channelmanager::ChannelShutdownState::NotShuttingDown),
+								funding_redeemscript: None,
+								holder_funding_pubkey: get_pubkey!(),
+								counter_funding_pubkey: None,
+								original_funding_outpoint: None,
+								channel_keys_id: [0u8; 32],
 							});
 						}
 						Some(&first_hops_vec[..])

lightning-block-sync/src/poll.rs

@@ -129,24 +129,25 @@ impl ValidatedBlockHeader {
 			return Err(BlockSourceError::persistent("invalid block height"));
 		}
 
-		let work = self.header.work();
-		if self.chainwork != previous_header.chainwork + work {
-			return Err(BlockSourceError::persistent("invalid chainwork"));
-		}
-
-		if let Network::Bitcoin = network {
-			if self.height % 2016 == 0 {
-				let target = self.header.target();
-				let previous_target = previous_header.header.target();
-				let min_target = previous_target >> 2;
-				let max_target = previous_target << 2;
-				if target > max_target || target < min_target {
-					return Err(BlockSourceError::persistent("invalid difficulty transition"))
-				}
-			} else if self.header.bits != previous_header.header.bits {
-				return Err(BlockSourceError::persistent("invalid difficulty"))
-			}
-		}
+		// let work = self.header.work();
+		// if self.chainwork != previous_header.chainwork + work {
+		// 	return Err(BlockSourceError::persistent("invalid chainwork"));
+		// }
+
+		// TODO(Tibo): This causes issues with Esplora, temporary fix.
+		// if let Network::Bitcoin = network {
+		// 	if self.height % 2016 == 0 {
+		// 		let target = self.header.target();
+		// 		let previous_target = previous_header.header.target();
+		// 		let min_target = previous_target >> 2;
+		// 		let max_target = previous_target << 2;
+		// 		if target > max_target || target < min_target {
+		// 			return Err(BlockSourceError::persistent("invalid difficulty transition"))
+		// 		}
+		// 	} else if self.header.bits != previous_header.header.bits {
+		// 		return Err(BlockSourceError::persistent("invalid difficulty"))
+		// 	}
+		// }
 
 		Ok(())
 	}

lightning-invoice/src/lib.rs

@@ -503,7 +503,7 @@ pub struct Bolt11InvoiceSignature(pub RecoverableSignature);
 
 impl PartialOrd for Bolt11InvoiceSignature {
 	fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
-		self.0.serialize_compact().1.partial_cmp(&other.0.serialize_compact().1)
+		Some(self.cmp(other))
 	}
 }
 

lightning-persister/src/lib.rs

@@ -106,7 +106,7 @@ impl FilesystemPersister {
 			let mut buffer = Cursor::new(&contents);
 			match <(BlockHash, ChannelMonitor<<SP::Target as SignerProvider>::Signer>)>::read(&mut buffer, (&*entropy_source, &*signer_provider)) {
 				Ok((blockhash, channel_monitor)) => {
-					if channel_monitor.get_funding_txo().0.txid != txid || channel_monitor.get_funding_txo().0.index != index {
+					if channel_monitor.get_original_funding_txo().0.txid != txid || channel_monitor.get_original_funding_txo().0.index != index {
 						return Err(std::io::Error::new(std::io::ErrorKind::InvalidData,
 									       "ChannelMonitor was stored in the wrong file"));
 					}

lightning/rustfmt.toml

@@ -0,0 +1 @@
+disable_all_formatting = true

lightning/src/chain/chainmonitor.rs

@@ -374,7 +374,7 @@ where C::Target: chain::Filter,
 		let monitor_states = self.monitors.read().unwrap();
 		for (_, monitor_state) in monitor_states.iter().filter(|(funding_outpoint, _)| {
 			for chan in ignored_channels {
-				if chan.funding_txo.as_ref() == Some(funding_outpoint) {
+				if chan.funding_txo.as_ref() == Some(funding_outpoint) || chan.original_funding_outpoint.as_ref() == Some(funding_outpoint) {
 					return false;
 				}
 			}
@@ -555,6 +555,15 @@ where C::Target: chain::Filter,
 			)
 		}
 	}
+
+	/// Retrieves the latest holder commitment transaction (and possibly HTLC transactions) for
+	/// the channel identified with the given `funding_txo`. Errors if no monitor is registered
+	/// for the given `funding_txo`.
+	pub fn get_latest_holder_commitment_txn(&self, funding_txo: &OutPoint) -> Result<Vec<bitcoin::Transaction>, ()> {
+		let monitors = self.monitors.read().unwrap();
+		let monitor = monitors.get(funding_txo).ok_or(())?;
+		Ok(monitor.monitor.get_latest_holder_commitment_txn_internal(&self.logger))
+	}
 }
 
 impl<ChannelSigner: WriteableEcdsaChannelSigner, C: Deref, T: Deref, F: Deref, L: Deref, P: Deref>
@@ -685,6 +694,31 @@ where C::Target: chain::Filter,
 		persist_res
 	}
 
+	fn update_channel_funding_txo(&self, old_funding_txo: OutPoint, new_funding_txo: OutPoint, channel_value_satoshis: u64) -> ChannelMonitorUpdateStatus {
+		let mut monitors = self.monitors.write().unwrap();
+		let monitor_opt = monitors.get_mut(&old_funding_txo);
+		match monitor_opt {
+			None => {
+				log_error!(self.logger, "Failed to update channel monitor funding txo: no such monitor registered");
+
+				// We should never ever trigger this from within ChannelManager. Technically a
+				// user could use this object with some proxying in between which makes this
+				// possible, but in tests and fuzzing, this should be a panic.
+				#[cfg(any(test, fuzzing))]
+				panic!("ChannelManager generated a channel update for a channel that was not yet registered!");
+				#[cfg(not(any(test, fuzzing)))]
+				return ChannelMonitorUpdateStatus::PermanentFailure;
+			},
+			Some(monitor_state) => {
+				let spk = monitor_state.monitor.update_funding_info(new_funding_txo, channel_value_satoshis);
+				if let Some(filter) = &self.chain_source {
+					filter.register_output(WatchedOutput { block_hash: None, outpoint: new_funding_txo, script_pubkey: spk });
+				}
+				return ChannelMonitorUpdateStatus::Completed;
+			}
+		}
+	}
+
 	/// Note that we persist the given `ChannelMonitor` update while holding the
 	/// `ChainMonitor` monitors lock.
 	fn update_channel(&self, funding_txo: OutPoint, update: &ChannelMonitorUpdate) -> ChannelMonitorUpdateStatus {
@@ -766,7 +800,7 @@ where C::Target: chain::Filter,
 				}
 				let monitor_events = monitor_state.monitor.get_and_clear_pending_monitor_events();
 				if monitor_events.len() > 0 {
-					let monitor_outpoint = monitor_state.monitor.get_funding_txo().0;
+					let monitor_outpoint = monitor_state.monitor.get_original_funding_txo().0;
 					let counterparty_node_id = monitor_state.monitor.get_counterparty_node_id();
 					pending_monitor_events.push((monitor_outpoint, monitor_events, counterparty_node_id));
 				}

lightning/src/chain/channelmonitor.rs

@@ -763,6 +763,7 @@ pub(crate) struct ChannelMonitorImpl<Signer: WriteableEcdsaChannelSigner> {
 	channel_keys_id: [u8; 32],
 	holder_revocation_basepoint: PublicKey,
 	funding_info: (OutPoint, Script),
+	original_funding_info: Option<(OutPoint, Script)>,
 	current_counterparty_commitment_txid: Option<Txid>,
 	prev_counterparty_commitment_txid: Option<Txid>,
 
@@ -945,6 +946,13 @@ impl<Signer: WriteableEcdsaChannelSigner> Writeable for ChannelMonitorImpl<Signe
 		writer.write_all(&self.funding_info.0.txid[..])?;
 		writer.write_all(&self.funding_info.0.index.to_be_bytes())?;
 		self.funding_info.1.write(writer)?;
+		if let Some(ref original_funding_info) = self.original_funding_info {
+			writer.write_all(&[0; 1])?;
+			original_funding_info.0.write(writer)?;
+			original_funding_info.1.write(writer)?;
+		} else {
+			writer.write_all(&[1; 1])?;
+		}
 		self.current_counterparty_commitment_txid.write(writer)?;
 		self.prev_counterparty_commitment_txid.write(writer)?;
 
@@ -1187,6 +1195,7 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitor<Signer> {
 			channel_keys_id,
 			holder_revocation_basepoint,
 			funding_info,
+			original_funding_info: None,
 			current_counterparty_commitment_txid: None,
 			prev_counterparty_commitment_txid: None,
 
@@ -1252,6 +1261,23 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitor<Signer> {
 			txid, htlc_outputs, commitment_number, their_per_commitment_point, logger)
 	}
 
+	pub(crate) fn update_funding_info(&self, fund_outpoint: OutPoint, channel_value_satoshis: u64) -> Script {
+		let mut inner = self.inner.lock().unwrap();
+		let script = inner.funding_info.1.clone();
+		if let Some(original) = inner.original_funding_info.as_ref() {
+			if fund_outpoint == original.0 {
+				inner.original_funding_info = None;
+			}
+		} else {
+			inner.original_funding_info = Some((inner.funding_info.0.clone(), inner.funding_info.1.clone()));
+		}
+		inner.outputs_to_watch.insert(fund_outpoint.txid, vec![(fund_outpoint.index as u32, script.clone())]);
+		inner.funding_info = (fund_outpoint, script.clone());
+		inner.channel_value_satoshis = channel_value_satoshis;
+		inner.onchain_tx_handler.signer.set_channel_value_satoshis(channel_value_satoshis);
+		script
+	}
+
 	#[cfg(test)]
 	fn provide_latest_holder_commitment_tx(
 		&self, holder_commitment_tx: HolderCommitmentTransaction,
@@ -1308,6 +1334,11 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitor<Signer> {
 		self.inner.lock().unwrap().get_funding_txo().clone()
 	}
 
+	///
+	pub fn get_original_funding_txo(&self) -> (OutPoint, Script) {
+		self.inner.lock().unwrap().get_original_funding_txo().clone()
+	}
+
 	/// Gets a list of txids, with their output scripts (in the order they appear in the
 	/// transaction), which we must learn about spends of via block_connected().
 	pub fn get_outputs_to_watch(&self) -> Vec<(Txid, Vec<(u32, Script)>)> {
@@ -1416,6 +1447,11 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitor<Signer> {
 		self.inner.lock().unwrap().get_latest_holder_commitment_txn(logger)
 	}
 
+	pub(crate) fn get_latest_holder_commitment_txn_internal<L: Deref>(&self, logger: &L) -> Vec<Transaction>
+	where L::Target: Logger {
+		self.inner.lock().unwrap().get_latest_holder_commitment_txn_internal(logger)
+	}
+
 	/// Unsafe test-only version of get_latest_holder_commitment_txn used by our test framework
 	/// to bypass HolderCommitmentTransaction state update lockdown after signature and generate
 	/// revoked commitment transaction.
@@ -2573,6 +2609,10 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitorImpl<Signer> {
 		&self.funding_info
 	}
 
+	pub fn get_original_funding_txo(&self) -> &(OutPoint, Script) {
+		&self.original_funding_info.as_ref().unwrap_or(&self.funding_info)
+	}
+
 	pub fn get_outputs_to_watch(&self) -> &HashMap<Txid, Vec<(u32, Script)>> {
 		// If we've detected a counterparty commitment tx on chain, we must include it in the set
 		// of outputs to watch for spends of, otherwise we're likely to lose user funds. Because
@@ -3018,8 +3058,12 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitorImpl<Signer> {
 	}
 
 	pub fn get_latest_holder_commitment_txn<L: Deref>(&mut self, logger: &L) -> Vec<Transaction> where L::Target: Logger {
-		log_debug!(logger, "Getting signed latest holder commitment transaction!");
 		self.holder_tx_signed = true;
+		self.get_latest_holder_commitment_txn_internal(logger)
+	}
+
+	pub(crate) fn get_latest_holder_commitment_txn_internal<L: Deref>(&mut self, logger: &L) -> Vec<Transaction> where L::Target: Logger {
+		log_debug!(logger, "Getting signed latest holder commitment transaction!");
 		let commitment_tx = self.onchain_tx_handler.get_fully_signed_holder_tx(&self.funding_redeemscript);
 		let txid = commitment_tx.txid();
 		let mut holder_transactions = vec![commitment_tx];
@@ -3186,7 +3230,14 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitorImpl<Signer> {
 				// (except for HTLC transactions for channels with anchor outputs), which is an easy
 				// way to filter out any potential non-matching txn for lazy filters.
 				let prevout = &tx.input[0].previous_output;
-				if prevout.txid == self.funding_info.0.txid && prevout.vout == self.funding_info.0.index as u32 {
+				let match_prevout = |outpoint: &OutPoint| {
+					prevout.txid == outpoint.txid && prevout.vout == outpoint.index as u32
+				};
+				let is_split = tx.output.len() == 2 && tx.output[0].script_pubkey == tx.output[1].script_pubkey;
+				let is_match = match_prevout(&self.funding_info.0) ||
+					(self.original_funding_info.is_some() && match_prevout(&self.original_funding_info.as_ref().unwrap().0) && !is_split);
+
+				if is_match {
 					let mut balance_spendable_csv = None;
 					log_info!(logger, "Channel {} closed by funding output spend in txid {}.",
 						log_bytes!(self.funding_info.0.to_channel_id()), txid);
@@ -3945,6 +3996,16 @@ impl<'a, 'b, ES: EntropySource, SP: SignerProvider> ReadableArgs<(&'a ES, &'b SP
 			index: Readable::read(reader)?,
 		};
 		let funding_info = (outpoint, Readable::read(reader)?);
+		let original_funding_info = match <u8 as Readable>::read(reader)? {
+			0 => {
+				let outpoint = Readable::read(reader)?;
+				let script = Readable::read(reader)?;
+				Some((outpoint, script))
+			},
+			1 => { None },
+			_ => return Err(DecodeError::InvalidValue),
+		};
+
 		let current_counterparty_commitment_txid = Readable::read(reader)?;
 		let prev_counterparty_commitment_txid = Readable::read(reader)?;
 
@@ -4141,6 +4202,7 @@ impl<'a, 'b, ES: EntropySource, SP: SignerProvider> ReadableArgs<(&'a ES, &'b SP
 			channel_keys_id,
 			holder_revocation_basepoint,
 			funding_info,
+			original_funding_info,
 			current_counterparty_commitment_txid,
 			prev_counterparty_commitment_txid,
 
@@ -4399,7 +4461,8 @@ mod tests {
 				selected_contest_delay: 67,
 			}),
 			funding_outpoint: Some(funding_outpoint),
-			channel_type_features: ChannelTypeFeatures::only_static_remote_key()
+			channel_type_features: ChannelTypeFeatures::only_static_remote_key(),
+			original_funding_outpoint: None,
 		};
 		// Prune with one old state and a holder commitment tx holding a few overlaps with the
 		// old state.

lightning/src/chain/mod.rs

@@ -295,6 +295,10 @@ pub trait Watch<ChannelSigner: WriteableEcdsaChannelSigner> {
 	/// [`update_monitor`]: channelmonitor::ChannelMonitor::update_monitor
 	fn update_channel(&self, funding_txo: OutPoint, update: &ChannelMonitorUpdate) -> ChannelMonitorUpdateStatus;
 
+	/// Update the outpoint funding the channel. To be used when the channel is split into two to
+	/// open a DLC channel with the same funding transaction.
+	fn update_channel_funding_txo(&self, old_funding_txo: OutPoint, new_funding_txo: OutPoint, channel_value_satoshis: u64) -> ChannelMonitorUpdateStatus;
+
 	/// Returns any monitor events since the last call. Subsequent calls must only return new
 	/// events.
 	///

lightning/src/chain/onchaintx.rs

@@ -172,6 +172,7 @@ impl Writeable for Option<Vec<Option<(usize, Signature)>>> {
 }
 
 /// The claim commonly referred to as the pre-signed second-stage HTLC transaction.
+#[derive(PartialEq)]
 pub(crate) struct ExternalHTLCClaim {
 	pub(crate) commitment_txid: Txid,
 	pub(crate) per_commitment_number: u64,
@@ -182,6 +183,7 @@ pub(crate) struct ExternalHTLCClaim {
 
 // Represents the different types of claims for which events are yielded externally to satisfy said
 // claims.
+#[derive(PartialEq)]
 pub(crate) enum ClaimEvent {
 	/// Event yielded to signal that the commitment transaction fee must be bumped to claim any
 	/// encumbered funds and proceed to HTLC resolution, if any HTLCs exist.