bolt12: Address JIT offers by node ID

Keep JIT offers independent of ephemeral LSPS2 leases and available
when the receiver does not yet have any channels. Negotiate payment
paths only after an invoice request arrives.

Co-Authored-By: HAL 9000

Author: tnull

src/payment/bolt12.rs

@@ -18,6 +18,7 @@ use lightning::ln::channelmanager::{OptionalOfferPaymentParams, PaymentId};
 use lightning::ln::outbound_payment::Retry;
 use lightning::offers::offer::{Amount, Offer as LdkOffer, OfferFromHrn, Quantity};
 use lightning::offers::parse::Bolt12SemanticError;
+use lightning::onion_message::messenger::NullMessageRouter;
 use lightning::routing::router::RouteParametersConfig;
 use lightning::sign::EntropySource;
 #[cfg(feature = "uniffi")]
@@ -207,9 +208,15 @@ impl Bolt12Payment {
 	}
 
 	pub(crate) fn receive_inner(
-		&self, amount_msat: u64, description: &str, expiry_secs: Option<u32>, quantity: Option<u64>,
+		&self, amount_msat: u64, description: &str, expiry_secs: Option<u32>,
+		quantity: Option<u64>, address_by_node_id: bool,
 	) -> Result<LdkOffer, Error> {
-		let mut offer_builder = self.channel_manager.create_offer_builder().map_err(|e| {
+		let offer_builder = if address_by_node_id {
+			self.channel_manager.create_offer_builder_using_router(NullMessageRouter {})
+		} else {
+			self.channel_manager.create_offer_builder()
+		};
+		let mut offer_builder = offer_builder.map_err(|e| {
 			log_error!(self.logger, "Failed to create offer builder: {:?}", e);
 			Error::OfferCreationFailed
 		})?;
@@ -244,9 +251,14 @@ impl Bolt12Payment {
 	}
 
 	fn receive_variable_amount_inner(
-		&self, description: &str, expiry_secs: Option<u32>,
+		&self, description: &str, expiry_secs: Option<u32>, address_by_node_id: bool,
 	) -> Result<LdkOffer, Error> {
-		let mut offer_builder = self.channel_manager.create_offer_builder().map_err(|e| {
+		let offer_builder = if address_by_node_id {
+			self.channel_manager.create_offer_builder_using_router(NullMessageRouter {})
+		} else {
+			self.channel_manager.create_offer_builder()
+		};
+		let mut offer_builder = offer_builder.map_err(|e| {
 			log_error!(self.logger, "Failed to create offer builder: {:?}", e);
 			Error::OfferCreationFailed
 		})?;
@@ -480,7 +492,7 @@ impl Bolt12Payment {
 	pub fn receive(
 		&self, amount_msat: u64, description: &str, expiry_secs: Option<u32>, quantity: Option<u64>,
 	) -> Result<Offer, Error> {
-		let offer = self.receive_inner(amount_msat, description, expiry_secs, quantity)?;
+		let offer = self.receive_inner(amount_msat, description, expiry_secs, quantity, false)?;
 		Ok(maybe_wrap(offer))
 	}
 
@@ -489,7 +501,7 @@ impl Bolt12Payment {
 	pub fn receive_variable_amount(
 		&self, description: &str, expiry_secs: Option<u32>,
 	) -> Result<Offer, Error> {
-		let offer = self.receive_variable_amount_inner(description, expiry_secs)?;
+		let offer = self.receive_variable_amount_inner(description, expiry_secs, false)?;
 		Ok(maybe_wrap(offer))
 	}
 
@@ -498,13 +510,14 @@ impl Bolt12Payment {
 	///
 	/// Creating the offer does not contact an LSP. LSPS2 payment parameters are selected only when
 	/// an invoice request for the offer is received, allowing the offer to outlive those parameters.
+	/// The offer contains no blinded message paths and is addressed directly to this node's ID.
 	/// If sufficient inbound liquidity is available over pre-existing channels, the payment may be
 	/// received over those channels without opening a new JIT channel.
 	pub fn receive_via_jit_channel(
 		&self, amount_msat: u64, description: &str, expiry_secs: Option<u32>,
 		quantity: Option<u64>, max_total_lsp_fee_limit_msat: Option<u64>,
 	) -> Result<Offer, Error> {
-		let offer = self.receive_inner(amount_msat, description, expiry_secs, quantity)?;
+		let offer = self.receive_inner(amount_msat, description, expiry_secs, quantity, true)?;
 		self.register_jit_offer(
 			&offer,
 			PendingOfferAmount::Fixed {
@@ -520,13 +533,14 @@ impl Bolt12Payment {
 	///
 	/// Creating the offer does not contact an LSP. LSPS2 payment parameters are selected only when
 	/// an invoice request for the offer is received, allowing the offer to outlive those parameters.
+	/// The offer contains no blinded message paths and is addressed directly to this node's ID.
 	/// If sufficient inbound liquidity is available over pre-existing channels, the payment may be
 	/// received over those channels without opening a new JIT channel.
 	pub fn receive_variable_amount_via_jit_channel(
 		&self, description: &str, expiry_secs: Option<u32>,
 		max_proportional_lsp_fee_limit_ppm_msat: Option<u64>,
 	) -> Result<Offer, Error> {
-		let offer = self.receive_variable_amount_inner(description, expiry_secs)?;
+		let offer = self.receive_variable_amount_inner(description, expiry_secs, true)?;
 		self.register_jit_offer(
 			&offer,
 			PendingOfferAmount::Variable {

src/payment/unified.rs

@@ -134,7 +134,7 @@ impl UnifiedPayment {
 		let onchain_address = self.onchain_payment.new_address()?;
 
 		let bolt12_offer =
-			match self.bolt12_payment.receive_inner(amount_msats, description, None, None) {
+			match self.bolt12_payment.receive_inner(amount_msats, description, None, None, false) {
 				Ok(offer) => Some(maybe_wrap(offer)),
 				Err(e) => {
 					log_error!(self.logger, "Failed to create offer: {}", e);