WIP: Include OffersContext in blinded paths

Author: jkczyz

lightning/src/blinded_path/message.rs

@@ -20,7 +20,9 @@ use crate::blinded_path::{BlindedHop, BlindedPath, IntroductionNode, NextMessage
 use crate::blinded_path::utils;
 use crate::io;
 use crate::io::Cursor;
-use crate::ln::onion_utils;
+use crate::ln::{PaymentHash, onion_utils};
+use crate::ln::channelmanager::PaymentId;
+use crate::offers::nonce::Nonce;
 use crate::onion_message::packet::ControlTlvs;
 use crate::sign::{NodeSigner, Recipient};
 use crate::crypto::streams::ChaChaPolyReadAdapter;
@@ -84,6 +86,27 @@ impl Writeable for ReceiveTlvs {
 	}
 }
 
+///
+pub enum OffersContext {
+	///
+	Unknown {},
+	///
+	InvoiceRequest {
+		///
+		nonce: Nonce,
+	},
+	///
+	InboundPayment {
+		///
+		payment_hash: PaymentHash,
+	},
+	///
+	OutboundPayment {
+		///
+		payment_id: PaymentId
+	},
+}
+
 /// Construct blinded onion message hops for the given `intermediate_nodes` and `recipient_node_id`.
 pub(super) fn blinded_hops<T: secp256k1::Signing + secp256k1::Verification>(
 	secp_ctx: &Secp256k1<T>, intermediate_nodes: &[ForwardNode], recipient_node_id: PublicKey,

lightning/src/ln/channelmanager.rs

@@ -32,7 +32,7 @@ use bitcoin::secp256k1::Secp256k1;
 use bitcoin::{secp256k1, Sequence};
 
 use crate::blinded_path::{BlindedPath, NodeIdLookUp};
-use crate::blinded_path::message::ForwardNode;
+use crate::blinded_path::message::{ForwardNode, OffersContext};
 use crate::blinded_path::payment::{Bolt12OfferContext, Bolt12RefundContext, PaymentConstraints, PaymentContext, ReceiveTlvs};
 use crate::chain;
 use crate::chain::{Confirm, ChannelMonitorUpdateStatus, Watch, BestBlock};
@@ -8377,7 +8377,8 @@ macro_rules! create_offer_builder { ($self: ident, $builder: ty) => {
 		let secp_ctx = &$self.secp_ctx;
 
 		let nonce = Nonce::from_entropy_source(entropy);
-		let path = $self.create_blinded_path_using_absolute_expiry(absolute_expiry)
+		let context = OffersContext::InvoiceRequest { nonce };
+		let path = $self.create_blinded_path_using_absolute_expiry(context, absolute_expiry)
 			.map_err(|_| Bolt12SemanticError::MissingPaths)?;
 		let builder = OfferBuilder::deriving_signing_pubkey(node_id, expanded_key, nonce, secp_ctx)
 			.chain_hash($self.chain_hash)
@@ -8447,7 +8448,8 @@ macro_rules! create_refund_builder { ($self: ident, $builder: ty) => {
 		let entropy = &*$self.entropy_source;
 		let secp_ctx = &$self.secp_ctx;
 
-		let path = $self.create_blinded_path_using_absolute_expiry(Some(absolute_expiry))
+		let context = OffersContext::OutboundPayment { payment_id };
+		let path = $self.create_blinded_path_using_absolute_expiry(context, Some(absolute_expiry))
 			.map_err(|_| Bolt12SemanticError::MissingPaths)?;
 		let builder = RefundBuilder::deriving_payer_id(
 			node_id, expanded_key, entropy, secp_ctx, amount_msats, payment_id
@@ -8570,7 +8572,9 @@ where
 			Some(payer_note) => builder.payer_note(payer_note),
 		};
 		let invoice_request = builder.build_and_sign()?;
-		let reply_path = self.create_blinded_path().map_err(|_| Bolt12SemanticError::MissingPaths)?;
+		let context = OffersContext::OutboundPayment { payment_id };
+		let reply_path = self.create_blinded_path(context)
+			.map_err(|_| Bolt12SemanticError::MissingPaths)?;
 
 		let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
 
@@ -8670,7 +8674,8 @@ where
 				)?;
 				let builder: InvoiceBuilder<DerivedSigningPubkey> = builder.into();
 				let invoice = builder.allow_mpp().build_and_sign(secp_ctx)?;
-				let reply_path = self.create_blinded_path()
+				let context = OffersContext::InboundPayment { payment_hash };
+				let reply_path = self.create_blinded_path(context)
 					.map_err(|_| Bolt12SemanticError::MissingPaths)?;
 
 				let mut pending_offers_messages = self.pending_offers_messages.lock().unwrap();
@@ -8803,15 +8808,15 @@ where
 	/// respectively, based on the given `absolute_expiry` as seconds since the Unix epoch. See
 	/// [`MAX_SHORT_LIVED_RELATIVE_EXPIRY`].
 	fn create_blinded_path_using_absolute_expiry(
-		&self, absolute_expiry: Option<Duration>
+		&self, context: OffersContext, absolute_expiry: Option<Duration>
 	) -> Result<BlindedPath, ()> {
 		let now = self.duration_since_epoch();
 		let max_short_lived_absolute_expiry = now.saturating_add(MAX_SHORT_LIVED_RELATIVE_EXPIRY);
 
 		if absolute_expiry.unwrap_or(Duration::MAX) <= max_short_lived_absolute_expiry {
 			self.create_compact_blinded_path()
 		} else {
-			self.create_blinded_path()
+			self.create_blinded_path(context)
 		}
 	}
 
@@ -8831,7 +8836,7 @@ where
 	/// Creates a blinded path by delegating to [`MessageRouter::create_blinded_paths`].
 	///
 	/// Errors if the `MessageRouter` errors or returns an empty `Vec`.
-	fn create_blinded_path(&self) -> Result<BlindedPath, ()> {
+	fn create_blinded_path(&self, _context: OffersContext) -> Result<BlindedPath, ()> {
 		let recipient = self.get_our_node_id();
 		let secp_ctx = &self.secp_ctx;