Merge pull request #1860 from wpaulino/open-channel-anchors-support

Support opening anchor channels and test end-to-end unilateral close

Author: TheBlueMatt

lightning/src/ln/channel.rs

@@ -4196,7 +4196,7 @@ where
 		let mut peer_state_lock = peer_state_mutex_opt.unwrap().lock().unwrap();
 		let peer_state = &mut *peer_state_lock;
 		let mut channel = match Channel::new_from_req(&self.fee_estimator, &self.entropy_source, &self.signer_provider,
-			counterparty_node_id.clone(), &peer_state.latest_features, msg, user_channel_id, &self.default_configuration,
+			counterparty_node_id.clone(), &self.channel_type_features(), &peer_state.latest_features, msg, user_channel_id, &self.default_configuration,
 			self.best_block.read().unwrap().height(), &self.logger, outbound_scid_alias)
 		{
 			Err(e) => {
@@ -6267,7 +6267,7 @@ pub(crate) fn provided_channel_features(config: &UserConfig) -> ChannelFeatures
 /// Fetches the set of [`ChannelTypeFeatures`] flags which are provided by or required by
 /// [`ChannelManager`].
 pub(crate) fn provided_channel_type_features(config: &UserConfig) -> ChannelTypeFeatures {
-	ChannelTypeFeatures::from_counterparty_init(&provided_init_features(config))
+	ChannelTypeFeatures::from_init(&provided_init_features(config))
 }
 
 /// Fetches the set of [`InitFeatures`] flags which are provided by or required by
@@ -6288,6 +6288,12 @@ pub fn provided_init_features(_config: &UserConfig) -> InitFeatures {
 	features.set_channel_type_optional();
 	features.set_scid_privacy_optional();
 	features.set_zero_conf_optional();
+	#[cfg(anchors)]
+	{ // Attributes are not allowed on if expressions on our current MSRV of 1.41.
+		if _config.channel_handshake_config.negotiate_anchors_zero_fee_htlc_tx {
+			features.set_anchors_zero_fee_htlc_tx_optional();
+		}
+	}
 	features
 }
 
@@ -7027,7 +7033,9 @@ where
 		let mut short_to_chan_info = HashMap::with_capacity(cmp::min(channel_count as usize, 128));
 		let mut channel_closures = Vec::new();
 		for _ in 0..channel_count {
-			let mut channel: Channel<<SP::Target as SignerProvider>::Signer> = Channel::read(reader, (&args.entropy_source, &args.signer_provider, best_block_height))?;
+			let mut channel: Channel<<SP::Target as SignerProvider>::Signer> = Channel::read(reader, (
+				&args.entropy_source, &args.signer_provider, best_block_height, &provided_channel_type_features(&args.default_config)
+			))?;
 			let funding_txo = channel.get_funding_txo().ok_or(DecodeError::InvalidValue)?;
 			funding_txo_set.insert(funding_txo.clone());
 			if let Some(ref mut monitor) = args.channel_monitors.get_mut(&funding_txo) {
@@ -8311,6 +8319,42 @@ mod tests {
 
 		nodes[1].node.handle_update_fee(&unkown_public_key, &update_fee_msg);
 	}
+
+	#[cfg(anchors)]
+	#[test]
+	fn test_anchors_zero_fee_htlc_tx_fallback() {
+		// Tests that if both nodes support anchors, but the remote node does not want to accept
+		// anchor channels at the moment, an error it sent to the local node such that it can retry
+		// the channel without the anchors feature.
+		let chanmon_cfgs = create_chanmon_cfgs(2);
+		let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
+		let mut anchors_config = test_default_channel_config();
+		anchors_config.channel_handshake_config.negotiate_anchors_zero_fee_htlc_tx = true;
+		anchors_config.manually_accept_inbound_channels = true;
+		let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[Some(anchors_config.clone()), Some(anchors_config.clone())]);
+		let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
+
+		nodes[0].node.create_channel(nodes[1].node.get_our_node_id(), 100_000, 0, 0, None).unwrap();
+		let open_channel_msg = get_event_msg!(nodes[0], MessageSendEvent::SendOpenChannel, nodes[1].node.get_our_node_id());
+		assert!(open_channel_msg.channel_type.as_ref().unwrap().supports_anchors_zero_fee_htlc_tx());
+
+		nodes[1].node.handle_open_channel(&nodes[0].node.get_our_node_id(), &open_channel_msg);
+		let events = nodes[1].node.get_and_clear_pending_events();
+		match events[0] {
+			Event::OpenChannelRequest { temporary_channel_id, .. } => {
+				nodes[1].node.force_close_broadcasting_latest_txn(&temporary_channel_id, &nodes[0].node.get_our_node_id()).unwrap();
+			}
+			_ => panic!("Unexpected event"),
+		}
+
+		let error_msg = get_err_msg!(nodes[1], nodes[0].node.get_our_node_id());
+		nodes[0].node.handle_error(&nodes[1].node.get_our_node_id(), &error_msg);
+
+		let open_channel_msg = get_event_msg!(nodes[0], MessageSendEvent::SendOpenChannel, nodes[1].node.get_our_node_id());
+		assert!(!open_channel_msg.channel_type.unwrap().supports_anchors_zero_fee_htlc_tx());
+
+		check_closed_event!(nodes[1], 1, ClosureReason::HolderForceClosed);
+	}
 }
 
 #[cfg(all(any(test, feature = "_test_utils"), feature = "_bench_unstable"))]

lightning/src/ln/channelmanager.rs

@@ -52,6 +52,10 @@
 //!     (see [BOLT-2](https://github.com/lightning/bolts/blob/master/02-peer-protocol.md) for more information).
 //! - `Keysend` - send funds to a node without an invoice
 //!     (see the [`Keysend` feature assignment proposal](https://github.com/lightning/bolts/issues/605#issuecomment-606679798) for more information).
+//! - `AnchorsZeroFeeHtlcTx` - requires/supports that commitment transactions include anchor outputs
+//!   and HTLC transactions are pre-signed with zero fee (see
+//!   [BOLT-3](https://github.com/lightning/bolts/blob/master/03-transactions.md) for more
+//!   information).
 //!
 //! [BOLT #9]: https://github.com/lightning/bolts/blob/master/09-features.md
 //! [messages]: crate::ln::msgs
@@ -122,7 +126,7 @@ mod sealed {
 		// Byte 1
 		VariableLengthOnion | StaticRemoteKey | PaymentSecret,
 		// Byte 2
-		BasicMPP | Wumbo,
+		BasicMPP | Wumbo | AnchorsZeroFeeHtlcTx,
 		// Byte 3
 		ShutdownAnySegwit,
 		// Byte 4
@@ -138,7 +142,7 @@ mod sealed {
 		// Byte 1
 		VariableLengthOnion | StaticRemoteKey | PaymentSecret,
 		// Byte 2
-		BasicMPP | Wumbo,
+		BasicMPP | Wumbo | AnchorsZeroFeeHtlcTx,
 		// Byte 3
 		ShutdownAnySegwit,
 		// Byte 4
@@ -176,7 +180,7 @@ mod sealed {
 		// Byte 1
 		StaticRemoteKey,
 		// Byte 2
-		,
+		AnchorsZeroFeeHtlcTx,
 		// Byte 3
 		,
 		// Byte 4
@@ -357,6 +361,9 @@ mod sealed {
 	define_feature!(19, Wumbo, [InitContext, NodeContext],
 		"Feature flags for `option_support_large_channel` (aka wumbo channels).", set_wumbo_optional, set_wumbo_required,
 		supports_wumbo, requires_wumbo);
+	define_feature!(23, AnchorsZeroFeeHtlcTx, [InitContext, NodeContext, ChannelTypeContext],
+		"Feature flags for `option_anchors_zero_fee_htlc_tx`.", set_anchors_zero_fee_htlc_tx_optional,
+		set_anchors_zero_fee_htlc_tx_required, supports_anchors_zero_fee_htlc_tx, requires_anchors_zero_fee_htlc_tx);
 	define_feature!(27, ShutdownAnySegwit, [InitContext, NodeContext],
 		"Feature flags for `opt_shutdown_anysegwit`.", set_shutdown_any_segwit_optional,
 		set_shutdown_any_segwit_required, supports_shutdown_anysegwit, requires_shutdown_anysegwit);
@@ -505,10 +512,10 @@ impl InvoiceFeatures {
 }
 
 impl ChannelTypeFeatures {
-	/// Constructs the implicit channel type based on the common supported types between us and our
-	/// counterparty
-	pub(crate) fn from_counterparty_init(counterparty_init: &InitFeatures) -> Self {
-		let mut ret = counterparty_init.to_context_internal();
+	// Maps the relevant `InitFeatures` to `ChannelTypeFeatures`. Any unknown features to
+	// `ChannelTypeFeatures` are not included in the result.
+	pub(crate) fn from_init(init: &InitFeatures) -> Self {
+		let mut ret = init.to_context_internal();
 		// ChannelTypeFeatures must only contain required bits, so we OR the required forms of all
 		// optional bits and then AND out the optional ones.
 		for byte in ret.flags.iter_mut() {
@@ -678,6 +685,24 @@ impl<T: sealed::Context> Features<T> {
 			(byte & unknown_features) != 0
 		})
 	}
+
+	// Returns true if the features within `self` are a subset of the features within `other`.
+	pub(crate) fn is_subset(&self, other: &Self) -> bool {
+		for (idx, byte) in self.flags.iter().enumerate() {
+			if let Some(other_byte) = other.flags.get(idx) {
+				if byte & other_byte != *byte {
+					// `self` has bits set that `other` doesn't.
+					return false;
+				}
+			} else {
+				if *byte > 0 {
+					// `self` has a non-zero byte that `other` doesn't.
+					return false;
+				}
+			}
+		}
+		true
+	}
 }
 
 impl<T: sealed::UpfrontShutdownScript> Features<T> {
@@ -704,6 +729,18 @@ impl<T: sealed::Wumbo> Features<T> {
 	}
 }
 
+impl<T: sealed::SCIDPrivacy> Features<T> {
+	pub(crate) fn clear_scid_privacy(&mut self) {
+		<T as sealed::SCIDPrivacy>::clear_bits(&mut self.flags);
+	}
+}
+
+impl<T: sealed::AnchorsZeroFeeHtlcTx> Features<T> {
+	pub(crate) fn clear_anchors_zero_fee_htlc_tx(&mut self) {
+		<T as sealed::AnchorsZeroFeeHtlcTx>::clear_bits(&mut self.flags);
+	}
+}
+
 #[cfg(test)]
 impl<T: sealed::UnknownFeature> Features<T> {
 	pub(crate) fn unknown() -> Self {
@@ -808,6 +845,7 @@ mod tests {
 		init_features.set_channel_type_optional();
 		init_features.set_scid_privacy_optional();
 		init_features.set_zero_conf_optional();
+		init_features.set_anchors_zero_fee_htlc_tx_optional();
 
 		assert!(init_features.initial_routing_sync());
 		assert!(!init_features.supports_upfront_shutdown_script());
@@ -826,7 +864,7 @@ mod tests {
 			assert_eq!(node_features.flags.len(), 7);
 			assert_eq!(node_features.flags[0], 0b00000010);
 			assert_eq!(node_features.flags[1], 0b01010001);
-			assert_eq!(node_features.flags[2], 0b00001010);
+			assert_eq!(node_features.flags[2], 0b10001010);
 			assert_eq!(node_features.flags[3], 0b00001000);
 			assert_eq!(node_features.flags[4], 0b10000000);
 			assert_eq!(node_features.flags[5], 0b10100000);
@@ -917,7 +955,7 @@ mod tests {
 		// required-StaticRemoteKey ChannelTypeFeatures.
 		let mut init_features = InitFeatures::empty();
 		init_features.set_static_remote_key_optional();
-		let converted_features = ChannelTypeFeatures::from_counterparty_init(&init_features);
+		let converted_features = ChannelTypeFeatures::from_init(&init_features);
 		assert_eq!(converted_features, ChannelTypeFeatures::only_static_remote_key());
 		assert!(!converted_features.supports_any_optional_bits());
 		assert!(converted_features.requires_static_remote_key());

lightning/src/ln/features.rs

@@ -61,17 +61,22 @@ pub fn confirm_transaction<'a, 'b, 'c, 'd>(node: &'a Node<'b, 'c, 'd>, tx: &Tran
 	connect_blocks(node, CHAN_CONFIRM_DEPTH - 1);
 	scid
 }
-/// Mine a signle block containing the given transaction
+/// Mine a single block containing the given transaction
 pub fn mine_transaction<'a, 'b, 'c, 'd>(node: &'a Node<'b, 'c, 'd>, tx: &Transaction) {
 	let height = node.best_block_info().1 + 1;
 	confirm_transaction_at(node, tx, height);
 }
+/// Mine a single block containing the given transactions
+pub fn mine_transactions<'a, 'b, 'c, 'd>(node: &'a Node<'b, 'c, 'd>, txn: &[&Transaction]) {
+	let height = node.best_block_info().1 + 1;
+	confirm_transactions_at(node, txn, height);
+}
 /// Mine the given transaction at the given height, mining blocks as required to build to that
 /// height
 ///
 /// Returns the SCID a channel confirmed in the given transaction will have, assuming the funding
 /// output is the 1st output in the transaction.
-pub fn confirm_transaction_at<'a, 'b, 'c, 'd>(node: &'a Node<'b, 'c, 'd>, tx: &Transaction, conf_height: u32) -> u64 {
+pub fn confirm_transactions_at<'a, 'b, 'c, 'd>(node: &'a Node<'b, 'c, 'd>, txn: &[&Transaction], conf_height: u32) -> u64 {
 	let first_connect_height = node.best_block_info().1 + 1;
 	assert!(first_connect_height <= conf_height);
 	if conf_height > first_connect_height {
@@ -84,10 +89,15 @@ pub fn confirm_transaction_at<'a, 'b, 'c, 'd>(node: &'a Node<'b, 'c, 'd>, tx: &T
 	for _ in 0..*node.network_chan_count.borrow() { // Make sure we don't end up with channels at the same short id by offsetting by chan_count
 		block.txdata.push(Transaction { version: 0, lock_time: PackedLockTime::ZERO, input: Vec::new(), output: Vec::new() });
 	}
-	block.txdata.push(tx.clone());
+	for tx in txn {
+		block.txdata.push((*tx).clone());
+	}
 	connect_block(node, &block);
 	scid_utils::scid_from_parts(conf_height as u64, block.txdata.len() as u64 - 1, 0).unwrap()
 }
+pub fn confirm_transaction_at<'a, 'b, 'c, 'd>(node: &'a Node<'b, 'c, 'd>, tx: &Transaction, conf_height: u32) -> u64 {
+	confirm_transactions_at(node, &[tx], conf_height)
+}
 
 /// The possible ways we may notify a ChannelManager of a new block
 #[derive(Clone, Copy, Debug, PartialEq)]

lightning/src/ln/functional_test_utils.rs

@@ -6861,7 +6861,7 @@ fn test_user_configurable_csv_delay() {
 	let mut open_channel = get_event_msg!(nodes[1], MessageSendEvent::SendOpenChannel, nodes[0].node.get_our_node_id());
 	open_channel.to_self_delay = 200;
 	if let Err(error) = Channel::new_from_req(&LowerBoundedFeeEstimator::new(&test_utils::TestFeeEstimator { sat_per_kw: Mutex::new(253) }),
-		&nodes[0].keys_manager, &nodes[0].keys_manager, nodes[1].node.get_our_node_id(), &nodes[1].node.init_features(), &open_channel, 0,
+		&nodes[0].keys_manager, &nodes[0].keys_manager, nodes[1].node.get_our_node_id(), &nodes[0].node.channel_type_features(), &nodes[1].node.init_features(), &open_channel, 0,
 		&low_our_to_self_config, 0, &nodes[0].logger, 42)
 	{
 		match error {
@@ -6893,7 +6893,7 @@ fn test_user_configurable_csv_delay() {
 	let mut open_channel = get_event_msg!(nodes[1], MessageSendEvent::SendOpenChannel, nodes[0].node.get_our_node_id());
 	open_channel.to_self_delay = 200;
 	if let Err(error) = Channel::new_from_req(&LowerBoundedFeeEstimator::new(&test_utils::TestFeeEstimator { sat_per_kw: Mutex::new(253) }),
-		&nodes[0].keys_manager, &nodes[0].keys_manager, nodes[1].node.get_our_node_id(), &nodes[1].node.init_features(), &open_channel, 0,
+		&nodes[0].keys_manager, &nodes[0].keys_manager, nodes[1].node.get_our_node_id(), &nodes[0].node.channel_type_features(), &nodes[1].node.init_features(), &open_channel, 0,
 		&high_their_to_self_config, 0, &nodes[0].logger, 42)
 	{
 		match error {