From 46f5fc740036a1a68ace56e46906a51c0e9892d8 Mon Sep 17 00:00:00 2001
From: Joost Jager <joost.jager@gmail.com>
Date: Wed, 25 Mar 2020 14:06:48 +0100
Subject: [PATCH] routing: distinguish between receiver amount and total amount
 in newRoute

---
 routing/pathfind.go        | 4 +++-
 routing/pathfind_test.go   | 1 +
 routing/payment_session.go | 1 +
 routing/router.go          | 2 ++
 4 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/routing/pathfind.go b/routing/pathfind.go
index 5507444a..b6879cc6 100644
--- a/routing/pathfind.go
+++ b/routing/pathfind.go
@@ -74,6 +74,7 @@ type edgePolicyWithSource struct {
 // custom records and payment address.
 type finalHopParams struct {
 	amt         lnwire.MilliSatoshi
+	totalAmt    lnwire.MilliSatoshi
 	cltvDelta   uint16
 	records     record.CustomSet
 	paymentAddr *[32]byte
@@ -177,7 +178,8 @@ func newRoute(sourceVertex route.Vertex,
 			// Otherwise attach the mpp record if it exists.
 			if finalHop.paymentAddr != nil {
 				mpp = record.NewMPP(
-					finalHop.amt, *finalHop.paymentAddr,
+					finalHop.totalAmt,
+					*finalHop.paymentAddr,
 				)
 			}
 		} else {
diff --git a/routing/pathfind_test.go b/routing/pathfind_test.go
index 193e752d..ab54534b 100644
--- a/routing/pathfind_test.go
+++ b/routing/pathfind_test.go
@@ -1327,6 +1327,7 @@ func TestNewRoute(t *testing.T) {
 				sourceVertex, testCase.hops, startingHeight,
 				finalHopParams{
 					amt:         testCase.paymentAmount,
+					totalAmt:    testCase.paymentAmount,
 					cltvDelta:   finalHopCLTV,
 					records:     nil,
 					paymentAddr: testCase.paymentAddr,
diff --git a/routing/payment_session.go b/routing/payment_session.go
index a28f6a6f..9f9c347c 100644
--- a/routing/payment_session.go
+++ b/routing/payment_session.go
@@ -196,6 +196,7 @@ func (p *paymentSession) RequestRoute(maxAmt, feeLimit lnwire.MilliSatoshi,
 		sourceVertex, path, height,
 		finalHopParams{
 			amt:         maxAmt,
+			totalAmt:    maxAmt,
 			cltvDelta:   finalCltvDelta,
 			records:     p.payment.DestCustomRecords,
 			paymentAddr: p.payment.PaymentAddr,
diff --git a/routing/router.go b/routing/router.go
index c554ceee..7d80305b 100644
--- a/routing/router.go
+++ b/routing/router.go
@@ -1456,6 +1456,7 @@ func (r *ChannelRouter) FindRoute(source, target route.Vertex,
 		source, path, uint32(currentHeight),
 		finalHopParams{
 			amt:       amt,
+			totalAmt:  amt,
 			cltvDelta: finalExpiry,
 			records:   destCustomRecords,
 		},
@@ -2513,6 +2514,7 @@ func (r *ChannelRouter) BuildRoute(amt *lnwire.MilliSatoshi,
 		source, pathEdges, uint32(height),
 		finalHopParams{
 			amt:       receiverAmt,
+			totalAmt:  receiverAmt,
 			cltvDelta: uint16(finalCltvDelta),
 			records:   nil,
 		},