Allow create_blinded_paths Function to Take Recipient TLVs as a Field

- Enabled `create_blinded_paths` to accept `RecipientData` TLVs as
  an input field.
- `RecipientData` is intended to be sent along with the `reply_path`
   to the counterparty.
- Added `RecipientData` in the `create_blinded_paths` flow, optionally
  appending it within the `reply_path`.
- Updated tests to verify the new feature.

Author: shaavan

fuzz/src/chanmon_consistency.rs

@@ -33,6 +33,7 @@ use bitcoin::hashes::sha256d::Hash as Sha256dHash;
 use bitcoin::hashes::Hash as TraitImport;
 use bitcoin::WPubkeyHash;
 
+use lightning::blinded_path::message::MessageContext;
 use lightning::blinded_path::payment::ReceiveTlvs;
 use lightning::blinded_path::BlindedPath;
 use lightning::chain;
@@ -138,7 +139,8 @@ impl MessageRouter for FuzzRouter {
 	}
 
 	fn create_blinded_paths<T: secp256k1::Signing + secp256k1::Verification>(
-		&self, _recipient: PublicKey, _peers: Vec<PublicKey>, _secp_ctx: &Secp256k1<T>,
+		&self, _recipient: PublicKey, _recipient_data: Option<MessageContext>,
+		_peers: Vec<PublicKey>, _secp_ctx: &Secp256k1<T>,
 	) -> Result<Vec<BlindedPath>, ()> {
 		unreachable!()
 	}

fuzz/src/full_stack.rs

@@ -30,6 +30,7 @@ use bitcoin::hashes::sha256d::Hash as Sha256dHash;
 use bitcoin::hashes::Hash as _;
 use bitcoin::WPubkeyHash;
 
+use lightning::blinded_path::message::MessageContext;
 use lightning::blinded_path::payment::ReceiveTlvs;
 use lightning::blinded_path::BlindedPath;
 use lightning::chain;
@@ -175,7 +176,8 @@ impl MessageRouter for FuzzRouter {
 	}
 
 	fn create_blinded_paths<T: secp256k1::Signing + secp256k1::Verification>(
-		&self, _recipient: PublicKey, _peers: Vec<PublicKey>, _secp_ctx: &Secp256k1<T>,
+		&self, _recipient: PublicKey, _recipient_data: Option<MessageContext>,
+		_peers: Vec<PublicKey>, _secp_ctx: &Secp256k1<T>,
 	) -> Result<Vec<BlindedPath>, ()> {
 		unreachable!()
 	}

fuzz/src/invoice_request_deser.rs

@@ -87,10 +87,22 @@ fn build_response<T: secp256k1::Signing + secp256k1::Verification>(
 		],
 	];
 	let paths = vec![
-		BlindedPath::new_for_message(&intermediate_nodes[0], pubkey(42), &entropy_source, secp_ctx)
-			.unwrap(),
-		BlindedPath::new_for_message(&intermediate_nodes[1], pubkey(42), &entropy_source, secp_ctx)
-			.unwrap(),
+		BlindedPath::new_for_message(
+			&intermediate_nodes[0],
+			pubkey(42),
+			None,
+			&entropy_source,
+			secp_ctx,
+		)
+		.unwrap(),
+		BlindedPath::new_for_message(
+			&intermediate_nodes[1],
+			pubkey(42),
+			None,
+			&entropy_source,
+			secp_ctx,
+		)
+		.unwrap(),
 	];
 
 	let payinfo = vec![

fuzz/src/onion_message.rs

@@ -95,7 +95,8 @@ impl MessageRouter for TestMessageRouter {
 	}
 
 	fn create_blinded_paths<T: secp256k1::Signing + secp256k1::Verification>(
-		&self, _recipient: PublicKey, _peers: Vec<PublicKey>, _secp_ctx: &Secp256k1<T>,
+		&self, _recipient: PublicKey, _recipient_data: Option<MessageContext>,
+		_peers: Vec<PublicKey>, _secp_ctx: &Secp256k1<T>,
 	) -> Result<Vec<BlindedPath>, ()> {
 		unreachable!()
 	}

fuzz/src/refund_deser.rs

@@ -76,10 +76,22 @@ fn build_response<T: secp256k1::Signing + secp256k1::Verification>(
 		],
 	];
 	let paths = vec![
-		BlindedPath::new_for_message(&intermediate_nodes[0], pubkey(42), &entropy_source, secp_ctx)
-			.unwrap(),
-		BlindedPath::new_for_message(&intermediate_nodes[1], pubkey(42), &entropy_source, secp_ctx)
-			.unwrap(),
+		BlindedPath::new_for_message(
+			&intermediate_nodes[0],
+			pubkey(42),
+			None,
+			&entropy_source,
+			secp_ctx,
+		)
+		.unwrap(),
+		BlindedPath::new_for_message(
+			&intermediate_nodes[1],
+			pubkey(42),
+			None,
+			&entropy_source,
+			secp_ctx,
+		)
+		.unwrap(),
 	];
 
 	let payinfo = vec![

lightning/src/blinded_path/message.rs

@@ -12,6 +12,7 @@
 //! [`BlindedPath`]: crate::blinded_path::BlindedPath
 
 use bitcoin::secp256k1::{self, PublicKey, Secp256k1, SecretKey};
+
 #[allow(unused_imports)]
 use crate::prelude::*;
 
@@ -155,7 +156,7 @@ impl_writeable_tlv_based_enum!(OffersContext,
 /// 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,
-	session_priv: &SecretKey
+	context: Option<MessageContext>, session_priv: &SecretKey
 ) -> Result<Vec<BlindedHop>, secp256k1::Error> {
 	let pks = intermediate_nodes.iter().map(|node| &node.node_id)
 		.chain(core::iter::once(&recipient_node_id));
@@ -167,7 +168,7 @@ pub(super) fn blinded_hops<T: secp256k1::Signing + secp256k1::Verification>(
 			None => NextMessageHop::NodeId(*pubkey),
 		})
 		.map(|next_hop| ControlTlvs::Forward(ForwardTlvs { next_hop, next_blinding_override: None }))
-		.chain(core::iter::once(ControlTlvs::Receive(ReceiveTlvs { context: None })));
+		.chain(core::iter::once(ControlTlvs::Receive(ReceiveTlvs{ context })));
 
 	utils::construct_blinded_hops(secp_ctx, pks, tlvs, session_priv)
 }

lightning/src/blinded_path/mod.rs

@@ -14,6 +14,7 @@ pub mod message;
 pub(crate) mod utils;
 
 use bitcoin::secp256k1::{self, PublicKey, Secp256k1, SecretKey};
+use message::MessageContext;
 use core::ops::Deref;
 
 use crate::ln::msgs::DecodeError;
@@ -123,9 +124,9 @@ pub struct BlindedHop {
 impl BlindedPath {
 	/// Create a one-hop blinded path for a message.
 	pub fn one_hop_for_message<ES: Deref, T: secp256k1::Signing + secp256k1::Verification>(
-		recipient_node_id: PublicKey, entropy_source: ES, secp_ctx: &Secp256k1<T>
+		recipient_node_id: PublicKey, context: Option<MessageContext>, entropy_source: ES, secp_ctx: &Secp256k1<T>
 	) -> Result<Self, ()> where ES::Target: EntropySource {
-		Self::new_for_message(&[], recipient_node_id, entropy_source, secp_ctx)
+		Self::new_for_message(&[], recipient_node_id, context, entropy_source, secp_ctx)
 	}
 
 	/// Create a blinded path for an onion message, to be forwarded along `node_pks`. The last node
@@ -135,7 +136,7 @@ impl BlindedPath {
 	//  TODO: make all payloads the same size with padding + add dummy hops
 	pub fn new_for_message<ES: Deref, T: secp256k1::Signing + secp256k1::Verification>(
 		intermediate_nodes: &[message::ForwardNode], recipient_node_id: PublicKey,
-		entropy_source: ES, secp_ctx: &Secp256k1<T>
+		context: Option<MessageContext>, entropy_source: ES, secp_ctx: &Secp256k1<T>
 	) -> Result<Self, ()> where ES::Target: EntropySource {
 		let introduction_node = IntroductionNode::NodeId(
 			intermediate_nodes.first().map_or(recipient_node_id, |n| n.node_id)
@@ -147,7 +148,8 @@ impl BlindedPath {
 			introduction_node,
 			blinding_point: PublicKey::from_secret_key(secp_ctx, &blinding_secret),
 			blinded_hops: message::blinded_hops(
-				secp_ctx, intermediate_nodes, recipient_node_id, &blinding_secret,
+				secp_ctx, intermediate_nodes, recipient_node_id,
+				context, &blinding_secret,
 			).map_err(|_| ())?,
 		})
 	}

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, OffersContext};
+use crate::blinded_path::message::{ForwardNode, MessageContext, OffersContext};
 use crate::blinded_path::payment::{Bolt12OfferContext, Bolt12RefundContext, PaymentConstraints, PaymentContext, ReceiveTlvs};
 use crate::chain;
 use crate::chain::{Confirm, ChannelMonitorUpdateStatus, Watch, BestBlock};
@@ -8814,7 +8814,7 @@ where
 		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()
+			self.create_compact_blinded_path(context)
 		} else {
 			self.create_blinded_path(context)
 		}
@@ -8836,7 +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, _context: OffersContext) -> Result<BlindedPath, ()> {
+	fn create_blinded_path(&self, context: OffersContext) -> Result<BlindedPath, ()> {
 		let recipient = self.get_our_node_id();
 		let secp_ctx = &self.secp_ctx;
 
@@ -8848,15 +8848,16 @@ where
 			.map(|(node_id, _)| *node_id)
 			.collect::<Vec<_>>();
 
+		let context = Some(MessageContext::Offers(context));
 		self.router
-			.create_blinded_paths(recipient, peers, secp_ctx)
+			.create_blinded_paths(recipient, context, peers, secp_ctx)
 			.and_then(|paths| paths.into_iter().next().ok_or(()))
 	}
 
 	/// Creates a blinded path by delegating to [`MessageRouter::create_compact_blinded_paths`].
 	///
 	/// Errors if the `MessageRouter` errors or returns an empty `Vec`.
-	fn create_compact_blinded_path(&self) -> Result<BlindedPath, ()> {
+	fn create_compact_blinded_path(&self, context: OffersContext) -> Result<BlindedPath, ()> {
 		let recipient = self.get_our_node_id();
 		let secp_ctx = &self.secp_ctx;
 
@@ -8875,8 +8876,9 @@ where
 			})
 			.collect::<Vec<_>>();
 
+		let context = Some(MessageContext::Offers(context));
 		self.router
-			.create_compact_blinded_paths(recipient, peers, secp_ctx)
+			.create_compact_blinded_paths(recipient, context, peers, secp_ctx)
 			.and_then(|paths| paths.into_iter().next().ok_or(()))
 	}
 

lightning/src/ln/offers_tests.rs

@@ -1412,6 +1412,14 @@ fn fails_sending_invoice_without_blinded_payment_paths_for_offer() {
 
 	let invoice_error = extract_invoice_error(david, &onion_message);
 	assert_eq!(invoice_error, InvoiceError::from(Bolt12SemanticError::MissingPaths));
+
+	// Confirm that david drops this failed payment from his pending outbound payments.
+	match get_event!(david, Event::InvoiceRequestFailed) {
+		Event::InvoiceRequestFailed { payment_id: pay_id } => {
+			assert_eq!(pay_id, payment_id)
+		},
+		_ => panic!("No Event::InvoiceRequestFailed"),
+	}
 }
 
 #[test]

lightning/src/onion_message/functional_tests.rs

@@ -372,7 +372,7 @@ fn one_blinded_hop() {
 	let test_msg = TestCustomMessage::Pong;
 
 	let secp_ctx = Secp256k1::new();
-	let blinded_path = BlindedPath::new_for_message(&[], nodes[1].node_id, &*nodes[1].entropy_source, &secp_ctx).unwrap();
+	let blinded_path = BlindedPath::new_for_message(&[], nodes[1].node_id, None, &*nodes[1].entropy_source, &secp_ctx).unwrap();
 	let destination = Destination::BlindedPath(blinded_path);
 	nodes[0].messenger.send_onion_message(test_msg, destination, None).unwrap();
 	nodes[1].custom_message_handler.expect_message(TestCustomMessage::Pong);
@@ -386,7 +386,7 @@ fn two_unblinded_two_blinded() {
 
 	let secp_ctx = Secp256k1::new();
 	let intermediate_nodes = [ForwardNode { node_id: nodes[3].node_id, short_channel_id: None }];
-	let blinded_path = BlindedPath::new_for_message(&intermediate_nodes, nodes[4].node_id, &*nodes[4].entropy_source, &secp_ctx).unwrap();
+	let blinded_path = BlindedPath::new_for_message(&intermediate_nodes, nodes[4].node_id, None, &*nodes[4].entropy_source, &secp_ctx).unwrap();
 	let path = OnionMessagePath {
 		intermediate_nodes: vec![nodes[1].node_id, nodes[2].node_id],
 		destination: Destination::BlindedPath(blinded_path),
@@ -408,7 +408,7 @@ fn three_blinded_hops() {
 		ForwardNode { node_id: nodes[1].node_id, short_channel_id: None },
 		ForwardNode { node_id: nodes[2].node_id, short_channel_id: None },
 	];
-	let blinded_path = BlindedPath::new_for_message(&intermediate_nodes, nodes[3].node_id, &*nodes[3].entropy_source, &secp_ctx).unwrap();
+	let blinded_path = BlindedPath::new_for_message(&intermediate_nodes, nodes[3].node_id, None, &*nodes[3].entropy_source, &secp_ctx).unwrap();
 	let destination = Destination::BlindedPath(blinded_path);
 
 	nodes[0].messenger.send_onion_message(test_msg, destination, None).unwrap();
@@ -430,7 +430,7 @@ fn async_response_over_one_blinded_hop() {
 
 	// 3. Simulate the creation of a Blinded Reply path provided by Bob.
 	let secp_ctx = Secp256k1::new();
-	let reply_path = BlindedPath::new_for_message(&[], nodes[1].node_id, &*nodes[1].entropy_source, &secp_ctx).unwrap();
+	let reply_path = BlindedPath::new_for_message(&[], nodes[1].node_id, None, &*nodes[1].entropy_source, &secp_ctx).unwrap();
 
 	// 4. Create a responder using the reply path for Alice.
 	let responder = Some(Responder::new(reply_path));
@@ -465,7 +465,7 @@ fn async_response_with_reply_path_succeeds() {
 
 	// Alice receives a message from Bob with an added reply_path for responding back.
 	let message = TestCustomMessage::Ping;
-	let reply_path = BlindedPath::new_for_message(&[], bob.node_id, &*bob.entropy_source, &secp_ctx).unwrap();
+	let reply_path = BlindedPath::new_for_message(&[], bob.node_id, None, &*bob.entropy_source, &secp_ctx).unwrap();
 
 	// Alice asynchronously responds to Bob, expecting a response back from him.
 	let responder = Responder::new(reply_path);
@@ -501,7 +501,7 @@ fn async_response_with_reply_path_fails() {
 
 	// Alice receives a message from Bob with an added reply_path for responding back.
 	let message = TestCustomMessage::Ping;
-	let reply_path = BlindedPath::new_for_message(&[], bob.node_id, &*bob.entropy_source, &secp_ctx).unwrap();
+	let reply_path = BlindedPath::new_for_message(&[], bob.node_id, None, &*bob.entropy_source, &secp_ctx).unwrap();
 
 	// Alice tries to asynchronously respond to Bob, but fails because the nodes are unannounced and
 	// disconnected. Thus, a reply path could no be created for the response.
@@ -545,7 +545,7 @@ fn we_are_intro_node() {
 		ForwardNode { node_id: nodes[0].node_id, short_channel_id: None },
 		ForwardNode { node_id: nodes[1].node_id, short_channel_id: None },
 	];
-	let blinded_path = BlindedPath::new_for_message(&intermediate_nodes, nodes[2].node_id, &*nodes[2].entropy_source, &secp_ctx).unwrap();
+	let blinded_path = BlindedPath::new_for_message(&intermediate_nodes, nodes[2].node_id, None, &*nodes[2].entropy_source, &secp_ctx).unwrap();
 	let destination = Destination::BlindedPath(blinded_path);
 
 	nodes[0].messenger.send_onion_message(test_msg.clone(), destination, None).unwrap();
@@ -554,7 +554,7 @@ fn we_are_intro_node() {
 
 	// Try with a two-hop blinded path where we are the introduction node.
 	let intermediate_nodes = [ForwardNode { node_id: nodes[0].node_id, short_channel_id: None }];
-	let blinded_path = BlindedPath::new_for_message(&intermediate_nodes, nodes[1].node_id, &*nodes[1].entropy_source, &secp_ctx).unwrap();
+	let blinded_path = BlindedPath::new_for_message(&intermediate_nodes, nodes[1].node_id, None, &*nodes[1].entropy_source, &secp_ctx).unwrap();
 	let destination = Destination::BlindedPath(blinded_path);
 	nodes[0].messenger.send_onion_message(test_msg, destination, None).unwrap();
 	nodes[1].custom_message_handler.expect_message(TestCustomMessage::Pong);
@@ -570,7 +570,7 @@ fn invalid_blinded_path_error() {
 
 	let secp_ctx = Secp256k1::new();
 	let intermediate_nodes = [ForwardNode { node_id: nodes[1].node_id, short_channel_id: None }];
-	let mut blinded_path = BlindedPath::new_for_message(&intermediate_nodes, nodes[2].node_id, &*nodes[2].entropy_source, &secp_ctx).unwrap();
+	let mut blinded_path = BlindedPath::new_for_message(&intermediate_nodes, nodes[2].node_id, None, &*nodes[2].entropy_source, &secp_ctx).unwrap();
 	blinded_path.blinded_hops.clear();
 	let destination = Destination::BlindedPath(blinded_path);
 	let err = nodes[0].messenger.send_onion_message(test_msg, destination, None).unwrap_err();
@@ -593,7 +593,7 @@ fn reply_path() {
 		ForwardNode { node_id: nodes[2].node_id, short_channel_id: None },
 		ForwardNode { node_id: nodes[1].node_id, short_channel_id: None },
 	];
-	let reply_path = BlindedPath::new_for_message(&intermediate_nodes, nodes[0].node_id, &*nodes[0].entropy_source, &secp_ctx).unwrap();
+	let reply_path = BlindedPath::new_for_message(&intermediate_nodes, nodes[0].node_id, None, &*nodes[0].entropy_source, &secp_ctx).unwrap();
 	nodes[0].messenger.send_onion_message_using_path(path, test_msg.clone(), Some(reply_path)).unwrap();
 	nodes[3].custom_message_handler.expect_message(TestCustomMessage::Ping);
 	pass_along_path(&nodes);
@@ -607,13 +607,13 @@ fn reply_path() {
 		ForwardNode { node_id: nodes[1].node_id, short_channel_id: None },
 		ForwardNode { node_id: nodes[2].node_id, short_channel_id: None },
 	];
-	let blinded_path = BlindedPath::new_for_message(&intermediate_nodes, nodes[3].node_id, &*nodes[3].entropy_source, &secp_ctx).unwrap();
+	let blinded_path = BlindedPath::new_for_message(&intermediate_nodes, nodes[3].node_id, None, &*nodes[3].entropy_source, &secp_ctx).unwrap();
 	let destination = Destination::BlindedPath(blinded_path);
 	let intermediate_nodes = [
 		ForwardNode { node_id: nodes[2].node_id, short_channel_id: None },
 		ForwardNode { node_id: nodes[1].node_id, short_channel_id: None },
 	];
-	let reply_path = BlindedPath::new_for_message(&intermediate_nodes, nodes[0].node_id, &*nodes[0].entropy_source, &secp_ctx).unwrap();
+	let reply_path = BlindedPath::new_for_message(&intermediate_nodes, nodes[0].node_id, None, &*nodes[0].entropy_source, &secp_ctx).unwrap();
 
 	nodes[0].messenger.send_onion_message(test_msg, destination, Some(reply_path)).unwrap();
 	nodes[3].custom_message_handler.expect_message(TestCustomMessage::Ping);
@@ -695,7 +695,7 @@ fn requests_peer_connection_for_buffered_messages() {
 
 	let intermediate_nodes = [ForwardNode { node_id: nodes[1].node_id, short_channel_id: None }];
 	let blinded_path = BlindedPath::new_for_message(
-		&intermediate_nodes, nodes[2].node_id, &*nodes[0].entropy_source, &secp_ctx
+		&intermediate_nodes, nodes[2].node_id, None, &*nodes[0].entropy_source, &secp_ctx
 	).unwrap();
 	let destination = Destination::BlindedPath(blinded_path);
 
@@ -733,7 +733,7 @@ fn drops_buffered_messages_waiting_for_peer_connection() {
 
 	let intermediate_nodes = [ForwardNode { node_id: nodes[1].node_id, short_channel_id: None }];
 	let blinded_path = BlindedPath::new_for_message(
-		&intermediate_nodes, nodes[2].node_id, &*nodes[0].entropy_source, &secp_ctx
+		&intermediate_nodes, nodes[2].node_id, None, &*nodes[0].entropy_source, &secp_ctx
 	).unwrap();
 	let destination = Destination::BlindedPath(blinded_path);
 
@@ -783,7 +783,7 @@ fn intercept_offline_peer_oms() {
 	let secp_ctx = Secp256k1::new();
 	let intermediate_nodes = [ForwardNode { node_id: nodes[1].node_id, short_channel_id: None }];
 	let blinded_path = BlindedPath::new_for_message(
-		&intermediate_nodes, nodes[2].node_id, &*nodes[2].entropy_source, &secp_ctx
+		&intermediate_nodes, nodes[2].node_id, None, &*nodes[2].entropy_source, &secp_ctx
 	).unwrap();
 	let destination = Destination::BlindedPath(blinded_path);