From 592bfd7c58e73eaa5cfd5032d982883878510037 Mon Sep 17 00:00:00 2001
From: Jeffrey Czyz <jkczyz@gmail.com>
Date: Thu, 11 Nov 2021 21:47:59 -0600
Subject: [PATCH] Add PaymentHash parameter to Router::find_route

Implementations of Router may need the payment hash in order to look up
pre-computed routes from a probe for a given payment. Add a PaymentHash
parameter to Router::find_route to allow for this.
---
 lightning-invoice/src/payment.rs | 37 +++++++++++++++-----------------
 lightning-invoice/src/utils.rs   |  4 ++--
 2 files changed, 19 insertions(+), 22 deletions(-)

diff --git a/lightning-invoice/src/payment.rs b/lightning-invoice/src/payment.rs
index 1e450296b..85786a90a 100644
--- a/lightning-invoice/src/payment.rs
+++ b/lightning-invoice/src/payment.rs
@@ -65,7 +65,7 @@
 //! # struct FakeRouter {};
 //! # impl<S: routing::Score> Router<S> for FakeRouter {
 //! #     fn find_route(
-//! #         &self, payer: &PublicKey, params: &RouteParameters,
+//! #         &self, payer: &PublicKey, params: &RouteParameters, payment_hash: &PaymentHash,
 //! #         first_hops: Option<&[&ChannelDetails]>, scorer: &S
 //! #     ) -> Result<Route, LightningError> { unimplemented!() }
 //! # }
@@ -180,8 +180,8 @@ pub trait Payer {
 pub trait Router<S: routing::Score> {
 	/// Finds a [`Route`] between `payer` and `payee` for a payment with the given values.
 	fn find_route(
-		&self, payer: &PublicKey, params: &RouteParameters, first_hops: Option<&[&ChannelDetails]>,
-		scorer: &S
+		&self, payer: &PublicKey, params: &RouteParameters, payment_hash: &PaymentHash,
+		first_hops: Option<&[&ChannelDetails]>, scorer: &S
 	) -> Result<Route, LightningError>;
 }
 
@@ -329,10 +329,8 @@ where
 		let payer = self.payer.node_id();
 		let first_hops = self.payer.first_hops();
 		let route = self.router.find_route(
-			&payer,
-			params,
-			Some(&first_hops.iter().collect::<Vec<_>>()),
-			&self.scorer.lock(),
+			&payer, params, &payment_hash, Some(&first_hops.iter().collect::<Vec<_>>()),
+			&self.scorer.lock()
 		).map_err(|e| PaymentError::Routing(e))?;
 
 		match send_payment(&route) {
@@ -392,7 +390,10 @@ where
 
 		let payer = self.payer.node_id();
 		let first_hops = self.payer.first_hops();
-		let route = self.router.find_route(&payer, &params, Some(&first_hops.iter().collect::<Vec<_>>()), &self.scorer.lock());
+		let route = self.router.find_route(
+			&payer, &params, &payment_hash, Some(&first_hops.iter().collect::<Vec<_>>()),
+			&self.scorer.lock()
+		);
 		if route.is_err() {
 			log_trace!(self.logger, "Failed to find a route for payment {}; not retrying (attempts: {})", log_bytes!(payment_hash.0), attempts);
 			return Err(());
@@ -1187,11 +1188,8 @@ mod tests {
 
 	impl<S: routing::Score> Router<S> for TestRouter {
 		fn find_route(
-			&self,
-			_payer: &PublicKey,
-			params: &RouteParameters,
-			_first_hops: Option<&[&ChannelDetails]>,
-			_scorer: &S,
+			&self, _payer: &PublicKey, params: &RouteParameters, _payment_hash: &PaymentHash,
+			_first_hops: Option<&[&ChannelDetails]>, _scorer: &S
 		) -> Result<Route, LightningError> {
 			Ok(Route {
 				payee: Some(params.payee.clone()), ..Self::route_for_value(params.final_value_msat)
@@ -1203,11 +1201,8 @@ mod tests {
 
 	impl<S: routing::Score> Router<S> for FailingRouter {
 		fn find_route(
-			&self,
-			_payer: &PublicKey,
-			_params: &RouteParameters,
-			_first_hops: Option<&[&ChannelDetails]>,
-			_scorer: &S,
+			&self, _payer: &PublicKey, _params: &RouteParameters, _payment_hash: &PaymentHash,
+			_first_hops: Option<&[&ChannelDetails]>, _scorer: &S
 		) -> Result<Route, LightningError> {
 			Err(LightningError { err: String::new(), action: ErrorAction::IgnoreError })
 		}
@@ -1370,8 +1365,10 @@ mod tests {
 	struct ManualRouter(RefCell<VecDeque<Result<Route, LightningError>>>);
 
 	impl<S: routing::Score> Router<S> for ManualRouter {
-		fn find_route(&self, _payer: &PublicKey, _params: &RouteParameters, _first_hops: Option<&[&ChannelDetails]>, _scorer: &S)
-		-> Result<Route, LightningError> {
+		fn find_route(
+			&self, _payer: &PublicKey, _params: &RouteParameters, _payment_hash: &PaymentHash,
+			_first_hops: Option<&[&ChannelDetails]>, _scorer: &S
+		) -> Result<Route, LightningError> {
 			self.0.borrow_mut().pop_front().unwrap()
 		}
 	}
diff --git a/lightning-invoice/src/utils.rs b/lightning-invoice/src/utils.rs
index 641a09ad7..ad94b0804 100644
--- a/lightning-invoice/src/utils.rs
+++ b/lightning-invoice/src/utils.rs
@@ -112,8 +112,8 @@ impl<G, L: Deref> DefaultRouter<G, L> where G: Deref<Target = NetworkGraph>, L::
 impl<G, L: Deref, S: routing::Score> Router<S> for DefaultRouter<G, L>
 where G: Deref<Target = NetworkGraph>, L::Target: Logger {
 	fn find_route(
-		&self, payer: &PublicKey, params: &RouteParameters, first_hops: Option<&[&ChannelDetails]>,
-		scorer: &S
+		&self, payer: &PublicKey, params: &RouteParameters, _payment_hash: &PaymentHash,
+		first_hops: Option<&[&ChannelDetails]>, scorer: &S
 	) -> Result<Route, LightningError> {
 		find_route(payer, params, &*self.network_graph, first_hops, &*self.logger, scorer)
 	}
-- 
2.39.5