Merge pull request lightningdevkit#3485 from dunxen/2024-12-cfgflagdualfunding

Reintroduce cfg(dual_funding) for handling of open_channel2 messages

Author: TheBlueMatt

Cargo.toml

@@ -65,4 +65,5 @@ check-cfg = [
     "cfg(require_route_graph_test)",
     "cfg(splicing)",
     "cfg(async_payments)",
+    "cfg(dual_funding)",
 ]

lightning/src/ln/channel.rs

@@ -1129,6 +1129,7 @@ pub(super) enum ChannelPhase<SP: Deref> where SP::Target: SignerProvider {
 	UnfundedInboundV1(InboundV1Channel<SP>),
 	#[allow(dead_code)] // TODO(dual_funding): Remove once creating V2 channels is enabled.
 	UnfundedOutboundV2(OutboundV2Channel<SP>),
+	#[allow(dead_code)] // TODO(dual_funding): Remove once accepting V2 channels is enabled.
 	UnfundedInboundV2(InboundV2Channel<SP>),
 	Funded(Channel<SP>),
 }
@@ -4089,7 +4090,7 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider {
 		})
 	}
 
-	#[cfg(test)]
+	#[cfg(all(test, dual_funding))]
 	pub fn get_initial_counterparty_commitment_signature_for_test<L: Deref>(
 		&mut self, logger: &L, channel_transaction_parameters: ChannelTransactionParameters,
 		counterparty_cur_commitment_point_override: PublicKey,
@@ -4159,6 +4160,7 @@ fn get_v2_channel_reserve_satoshis(channel_value_satoshis: u64, dust_limit_satos
 	cmp::min(channel_value_satoshis, cmp::max(q, dust_limit_satoshis))
 }
 
+#[allow(dead_code)] // TODO(dual_funding): Remove once V2 channels is enabled.
 pub(super) fn calculate_our_funding_satoshis(
 	is_initiator: bool, funding_inputs: &[(TxIn, TransactionU16LenLimited)],
 	total_witness_weight: Weight, funding_feerate_sat_per_1000_weight: u32,
@@ -4208,6 +4210,7 @@ pub(super) struct DualFundingChannelContext {
 	/// to the current block height to align incentives against fee-sniping.
 	pub funding_tx_locktime: LockTime,
 	/// The feerate set by the initiator to be used for the funding transaction.
+	#[allow(dead_code)] // TODO(dual_funding): Remove once V2 channels is enabled.
 	pub funding_feerate_sat_per_1000_weight: u32,
 	/// The funding inputs we will be contributing to the channel.
 	///
@@ -8292,6 +8295,7 @@ pub(super) struct OutboundV1Channel<SP: Deref> where SP::Target: SignerProvider
 }
 
 impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
+	#[allow(dead_code)] // TODO(dual_funding): Remove once opending V2 channels is enabled.
 	pub fn new<ES: Deref, F: Deref, L: Deref>(
 		fee_estimator: &LowerBoundedFeeEstimator<F>, entropy_source: &ES, signer_provider: &SP, counterparty_node_id: PublicKey, their_features: &InitFeatures,
 		channel_value_satoshis: u64, push_msat: u64, user_id: u128, config: &UserConfig, current_chain_height: u32,
@@ -9016,6 +9020,7 @@ pub(super) struct InboundV2Channel<SP: Deref> where SP::Target: SignerProvider {
 impl<SP: Deref> InboundV2Channel<SP> where SP::Target: SignerProvider {
 	/// Creates a new dual-funded channel from a remote side's request for one.
 	/// Assumes chain_hash has already been checked and corresponds with what we expect!
+	#[allow(dead_code)] // TODO(dual_funding): Remove once V2 channels is enabled.
 	pub fn new<ES: Deref, F: Deref, L: Deref>(
 		fee_estimator: &LowerBoundedFeeEstimator<F>, entropy_source: &ES, signer_provider: &SP,
 		holder_node_id: PublicKey, counterparty_node_id: PublicKey, our_supported_features: &ChannelTypeFeatures,
@@ -9124,6 +9129,7 @@ impl<SP: Deref> InboundV2Channel<SP> where SP::Target: SignerProvider {
 	/// should be sent back to the counterparty node.
 	///
 	/// [`msgs::AcceptChannelV2`]: crate::ln::msgs::AcceptChannelV2
+	#[allow(dead_code)] // TODO(dual_funding): Remove once V2 channels is enabled.
 	pub fn accept_inbound_dual_funded_channel(&self) -> msgs::AcceptChannelV2 {
 		if self.context.is_outbound() {
 			debug_assert!(false, "Tried to send accept_channel for an outbound channel?");
@@ -9146,6 +9152,7 @@ impl<SP: Deref> InboundV2Channel<SP> where SP::Target: SignerProvider {
 	/// use [`InboundV1Channel::accept_inbound_channel`] instead.
 	///
 	/// [`msgs::AcceptChannelV2`]: crate::ln::msgs::AcceptChannelV2
+	#[allow(dead_code)] // TODO(dual_funding): Remove once V2 channels is enabled.
 	fn generate_accept_channel_v2_message(&self) -> msgs::AcceptChannelV2 {
 		let first_per_commitment_point = self.context.holder_signer.as_ref().get_per_commitment_point(
 			self.unfunded_context.transaction_number(), &self.context.secp_ctx)

lightning/src/ln/channelmanager.rs

@@ -48,7 +48,9 @@ use crate::events::{self, Event, EventHandler, EventsProvider, InboundChannelFun
 use crate::ln::inbound_payment;
 use crate::ln::types::ChannelId;
 use crate::types::payment::{PaymentHash, PaymentPreimage, PaymentSecret};
-use crate::ln::channel::{self, Channel, ChannelPhase, ChannelError, ChannelUpdateStatus, ShutdownResult, UpdateFulfillCommitFetch, OutboundV1Channel, InboundV1Channel, WithChannelContext, InboundV2Channel, InteractivelyFunded as _};
+use crate::ln::channel::{self, Channel, ChannelPhase, ChannelError, ChannelUpdateStatus, ShutdownResult, UpdateFulfillCommitFetch, OutboundV1Channel, InboundV1Channel, WithChannelContext, InteractivelyFunded as _};
+#[cfg(any(dual_funding, splicing))]
+use crate::ln::channel::InboundV2Channel;
 use crate::ln::channel_state::ChannelDetails;
 use crate::types::features::{Bolt12InvoiceFeatures, ChannelFeatures, ChannelTypeFeatures, InitFeatures, NodeFeatures};
 #[cfg(any(feature = "_test_utils", test))]
@@ -1391,11 +1393,13 @@ impl <SP: Deref> PeerState<SP> where SP::Target: SignerProvider {
 #[derive(Clone)]
 pub(super) enum OpenChannelMessage {
 	V1(msgs::OpenChannel),
+	#[cfg(dual_funding)]
 	V2(msgs::OpenChannelV2),
 }
 
 pub(super) enum OpenChannelMessageRef<'a> {
 	V1(&'a msgs::OpenChannel),
+	#[cfg(dual_funding)]
 	V2(&'a msgs::OpenChannelV2),
 }
 
@@ -7651,8 +7655,8 @@ This indicates a bug inside LDK. Please report this error at https://github.com/
 
 	fn do_accept_inbound_channel(
 		&self, temporary_channel_id: &ChannelId, counterparty_node_id: &PublicKey, accept_0conf: bool,
-		user_channel_id: u128, funding_inputs: Vec<(TxIn, TransactionU16LenLimited)>,
-		total_witness_weight: Weight,
+		user_channel_id: u128, _funding_inputs: Vec<(TxIn, TransactionU16LenLimited)>,
+		_total_witness_weight: Weight,
 	) -> Result<(), APIError> {
 		let logger = WithContext::from(&self.logger, Some(*counterparty_node_id), Some(*temporary_channel_id), None);
 		let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
@@ -7696,10 +7700,11 @@ This indicates a bug inside LDK. Please report this error at https://github.com/
 							(*temporary_channel_id, ChannelPhase::UnfundedInboundV1(channel), message_send_event)
 						})
 					},
+					#[cfg(dual_funding)]
 					OpenChannelMessage::V2(open_channel_msg) => {
 						InboundV2Channel::new(&self.fee_estimator, &self.entropy_source, &self.signer_provider,
 							self.get_our_node_id(), *counterparty_node_id, &self.channel_type_features(), &peer_state.latest_features,
-							&open_channel_msg, funding_inputs, total_witness_weight, user_channel_id,
+							&open_channel_msg, _funding_inputs, _total_witness_weight, user_channel_id,
 							&self.default_configuration, best_block_height, &self.logger
 						).map_err(|_| MsgHandleErrInternal::from_chan_no_close(
 							ChannelError::Close(
@@ -7852,6 +7857,7 @@ This indicates a bug inside LDK. Please report this error at https://github.com/
 	fn internal_open_channel(&self, counterparty_node_id: &PublicKey, msg: OpenChannelMessageRef<'_>) -> Result<(), MsgHandleErrInternal> {
 		let common_fields = match msg {
 			OpenChannelMessageRef::V1(msg) => &msg.common_fields,
+			#[cfg(dual_funding)]
 			OpenChannelMessageRef::V2(msg) => &msg.common_fields,
 		};
 
@@ -7929,6 +7935,7 @@ This indicates a bug inside LDK. Please report this error at https://github.com/
 				funding_satoshis: common_fields.funding_satoshis,
 				channel_negotiation_type: match msg {
 					OpenChannelMessageRef::V1(msg) => InboundChannelFunds::PushMsat(msg.push_msat),
+					#[cfg(dual_funding)]
 					OpenChannelMessageRef::V2(_) => InboundChannelFunds::DualFunded,
 				},
 				channel_type,
@@ -7938,6 +7945,7 @@ This indicates a bug inside LDK. Please report this error at https://github.com/
 			peer_state.inbound_channel_request_by_id.insert(channel_id, InboundChannelRequest {
 				open_channel_msg: match msg {
 					OpenChannelMessageRef::V1(msg) => OpenChannelMessage::V1(msg.clone()),
+					#[cfg(dual_funding)]
 					OpenChannelMessageRef::V2(msg) => OpenChannelMessage::V2(msg.clone()),
 				},
 				ticks_remaining: UNACCEPTED_INBOUND_CHANNEL_AGE_LIMIT_TICKS,
@@ -7973,6 +7981,7 @@ This indicates a bug inside LDK. Please report this error at https://github.com/
 				});
 				(ChannelPhase::UnfundedInboundV1(channel), message_send_event)
 			},
+			#[cfg(dual_funding)]
 			OpenChannelMessageRef::V2(msg) => {
 				let channel = InboundV2Channel::new(&self.fee_estimator, &self.entropy_source,
 					&self.signer_provider, self.get_our_node_id(), *counterparty_node_id,
@@ -11271,6 +11280,7 @@ where
 		// Note that we never need to persist the updated ChannelManager for an inbound
 		// open_channel message - pre-funded channels are never written so there should be no
 		// change to the contents.
+		#[cfg(dual_funding)]
 		let _persistence_guard = PersistenceNotifierGuard::optionally_notify(self, || {
 			let res = self.internal_open_channel(&counterparty_node_id, OpenChannelMessageRef::V2(msg));
 			let persist = match &res {
@@ -11283,6 +11293,10 @@ where
 			let _ = handle_error!(self, res, counterparty_node_id);
 			persist
 		});
+		#[cfg(not(dual_funding))]
+		let _: Result<(), _> = handle_error!(self, Err(MsgHandleErrInternal::send_err_msg_no_close(
+			"Dual-funded channels not supported".to_owned(),
+			msg.common_fields.temporary_channel_id.clone())), counterparty_node_id);
 	}
 
 	fn handle_accept_channel(&self, counterparty_node_id: PublicKey, msg: &msgs::AcceptChannel) {
@@ -12334,6 +12348,7 @@ pub fn provided_init_features(config: &UserConfig) -> InitFeatures {
 	if config.channel_handshake_config.negotiate_anchors_zero_fee_htlc_tx {
 		features.set_anchors_zero_fee_htlc_tx_optional();
 	}
+	#[cfg(dual_funding)]
 	features.set_dual_fund_optional();
 	features
 }

lightning/src/ln/dual_funding_tests.rs

@@ -9,32 +9,36 @@
 
 //! Tests that test the creation of dual-funded channels in ChannelManager.
 
-use bitcoin::Weight;
-
-use crate::chain::chaininterface::{ConfirmationTarget, FeeEstimator, LowerBoundedFeeEstimator};
-use crate::events::{Event, MessageSendEvent, MessageSendEventsProvider};
-use crate::ln::chan_utils::{
-	make_funding_redeemscript, ChannelPublicKeys, ChannelTransactionParameters,
-	CounterpartyChannelTransactionParameters,
-};
-use crate::ln::channel::{
-	calculate_our_funding_satoshis, OutboundV2Channel, MIN_CHAN_DUST_LIMIT_SATOSHIS,
+#[cfg(dual_funding)]
+use {
+	crate::chain::chaininterface::{ConfirmationTarget, FeeEstimator, LowerBoundedFeeEstimator},
+	crate::events::{Event, MessageSendEvent, MessageSendEventsProvider},
+	crate::ln::chan_utils::{
+		make_funding_redeemscript, ChannelPublicKeys, ChannelTransactionParameters,
+		CounterpartyChannelTransactionParameters,
+	},
+	crate::ln::channel::{
+		calculate_our_funding_satoshis, OutboundV2Channel, MIN_CHAN_DUST_LIMIT_SATOSHIS,
+	},
+	crate::ln::channel_keys::{DelayedPaymentBasepoint, HtlcBasepoint, RevocationBasepoint},
+	crate::ln::functional_test_utils::*,
+	crate::ln::msgs::ChannelMessageHandler,
+	crate::ln::msgs::{CommitmentSigned, TxAddInput, TxAddOutput, TxComplete},
+	crate::ln::types::ChannelId,
+	crate::prelude::*,
+	crate::sign::{ChannelSigner as _, P2WPKH_WITNESS_WEIGHT},
+	crate::util::ser::TransactionU16LenLimited,
+	crate::util::test_utils,
+	bitcoin::Weight,
 };
-use crate::ln::channel_keys::{DelayedPaymentBasepoint, HtlcBasepoint, RevocationBasepoint};
-use crate::ln::functional_test_utils::*;
-use crate::ln::msgs::ChannelMessageHandler;
-use crate::ln::msgs::{CommitmentSigned, TxAddInput, TxAddOutput, TxComplete};
-use crate::ln::types::ChannelId;
-use crate::prelude::*;
-use crate::sign::{ChannelSigner as _, P2WPKH_WITNESS_WEIGHT};
-use crate::util::ser::TransactionU16LenLimited;
-use crate::util::test_utils;
 
+#[cfg(dual_funding)]
 // Dual-funding: V2 Channel Establishment Tests
 struct V2ChannelEstablishmentTestSession {
 	initiator_input_value_satoshis: u64,
 }
 
+#[cfg(dual_funding)]
 // TODO(dual_funding): Use real node and API for creating V2 channels as initiator when available,
 // instead of manually constructing messages.
 fn do_test_v2_channel_establishment(
@@ -252,6 +256,7 @@ fn do_test_v2_channel_establishment(
 }
 
 #[test]
+#[cfg(dual_funding)]
 fn test_v2_channel_establishment() {
 	// Only initiator contributes, no persist pending
 	do_test_v2_channel_establishment(

lightning/src/ln/peer_handler.rs

@@ -340,6 +340,7 @@ impl ChannelMessageHandler for ErroringMessageHandler {
 		features.set_basic_mpp_optional();
 		features.set_wumbo_optional();
 		features.set_shutdown_any_segwit_optional();
+		#[cfg(dual_funding)]
 		features.set_dual_fund_optional();
 		features.set_channel_type_optional();
 		features.set_scid_privacy_optional();
@@ -1820,8 +1821,8 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
 			wire::Message::OpenChannel(msg) => {
 				self.message_handler.chan_handler.handle_open_channel(their_node_id, &msg);
 			},
-			wire::Message::OpenChannelV2(msg) => {
-				self.message_handler.chan_handler.handle_open_channel_v2(their_node_id, &msg);
+			wire::Message::OpenChannelV2(_msg) => {
+				self.message_handler.chan_handler.handle_open_channel_v2(their_node_id, &_msg);
 			},
 			wire::Message::AcceptChannel(msg) => {
 				self.message_handler.chan_handler.handle_accept_channel(their_node_id, &msg);

pending_changelog/3137-accept-dual-funding-without-contributing.txt

@@ -1,4 +1,4 @@
-# API Updates
+# API Updates (0.2)
  * Accepting dual-funded (V2 establishment) channels (without contibuting) is now supported (#3137).
    Some particulars to be aware of for this feature:
    * Creating dual-funded channels is not yet supported.

pending_changelog/3137-channel-negotiation-type.txt

@@ -0,0 +1,7 @@
+# API Updates
+ * `Event::OpenChannelRequest::push_msat` has been replaced by the field `channel_negotiation_type` to
+   differentiate between an inbound request for a dual-funded (V2) or non-dual-funded (V1) channel to be
+   opened, with value being either of the enum variants `InboundChannelFunds::DualFunded` and
+   `InboundChannelFunds::PushMsat(u64)` corresponding to V2 and V1 channel open requests respectively.
+   This is in preparation for supporting accepting dual-funded channels, which will be available in a later release.
+