[2/3]: Support Forwarding of Blinded Payments

config.go

@@ -626,8 +626,9 @@ func DefaultConfig() Config {
 			RejectCacheSize:  channeldb.DefaultRejectCacheSize,
 			ChannelCacheSize: channeldb.DefaultChannelCacheSize,
 		},
-		Prometheus: lncfg.DefaultPrometheus(),
-		Watchtower: lncfg.DefaultWatchtowerCfg(defaultTowerDir),
+		Prometheus:      lncfg.DefaultPrometheus(),
+		Watchtower:      lncfg.DefaultWatchtowerCfg(defaultTowerDir),
+		ProtocolOptions: lncfg.DefaultProtocol(),
 		HealthChecks: &lncfg.HealthCheckConfig{
 			ChainCheck: &lncfg.CheckConfig{
 				Interval: defaultChainInterval,

contractcourt/htlc_incoming_contest_resolver.go

@@ -7,7 +7,6 @@ import (
 	"fmt"
 	"io"
 
-	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/lightningnetwork/lnd/channeldb"
@@ -18,7 +17,6 @@ import (
 	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/queue"
-	"github.com/lightningnetwork/lnd/tlv"
 )
 
 // htlcIncomingContestResolver is a ContractResolver that's able to resolve an
@@ -522,18 +520,15 @@ func (h *htlcIncomingContestResolver) Supplement(htlc channeldb.HTLC) {
 func (h *htlcIncomingContestResolver) decodePayload() (*hop.Payload,
 	[]byte, error) {
 
-	var blindingPoint *btcec.PublicKey
-	h.htlc.BlindingPoint.WhenSome(
-		func(b tlv.RecordT[lnwire.BlindingPointTlvType,
-			*btcec.PublicKey]) {
-
-			blindingPoint = b.Val
-		},
-	)
+	blindingInfo := hop.ReconstructBlindingInfo{
+		IncomingAmt:    h.htlc.Amt,
+		IncomingExpiry: h.htlc.RefundTimeout,
+		BlindingKey:    h.htlc.BlindingPoint,
+	}
 
 	onionReader := bytes.NewReader(h.htlc.OnionBlob[:])
 	iterator, err := h.OnionProcessor.ReconstructHopIterator(
-		onionReader, h.htlc.RHash[:], blindingPoint,
+		onionReader, h.htlc.RHash[:], blindingInfo,
 	)
 	if err != nil {
 		return nil, nil, err

contractcourt/htlc_incoming_contest_resolver_test.go

@@ -6,7 +6,6 @@ import (
 	"io/ioutil"
 	"testing"
 
-	"github.com/btcsuite/btcd/btcec/v2"
 	sphinx "github.com/lightningnetwork/lightning-onion"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
@@ -290,7 +289,7 @@ type mockOnionProcessor struct {
 }
 
 func (o *mockOnionProcessor) ReconstructHopIterator(r io.Reader, rHash []byte,
-	blindingPoint *btcec.PublicKey) (hop.Iterator, error) {
+	_ hop.ReconstructBlindingInfo) (hop.Iterator, error) {
 
 	data, err := ioutil.ReadAll(r)
 	if err != nil {

contractcourt/interfaces.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"io"
 
-	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/channeldb/models"
@@ -42,7 +41,7 @@ type OnionProcessor interface {
 	// ReconstructHopIterator attempts to decode a valid sphinx packet from
 	// the passed io.Reader instance.
 	ReconstructHopIterator(r io.Reader, rHash []byte,
-		blindingKey *btcec.PublicKey) (hop.Iterator, error)
+		blindingInfo hop.ReconstructBlindingInfo) (hop.Iterator, error)
 }
 
 // UtxoSweeper defines the sweep functions that contract court requires.

docs/release-notes/release-notes-0.18.0.md

@@ -187,7 +187,9 @@ call where arguments were swapped.
 bitcoin peers' feefilter values into account](https://github.com/lightningnetwork/lnd/pull/8418).
 
 * [Preparatory work](https://github.com/lightningnetwork/lnd/pull/8159) for 
-  forwarding of blinded routes was added.
+  forwarding of blinded routes was added, along with [support](https://github.com/lightningnetwork/lnd/pull/8160)
+  for forwarding blinded payments. Forwarding of blinded payments is disabled 
+  by default, and the feature is not yet advertised to the network.
 
 ## RPC Additions
 

htlcswitch/hop/forwarding_info.go

@@ -22,4 +22,9 @@ type ForwardingInfo struct {
 	// OutgoingCTLV is the specified value of the CTLV timelock to be used
 	// in the outgoing HTLC.
 	OutgoingCTLV uint32
+
+	// NextBlinding is an optional blinding point to be passed to the next
+	// node in UpdateAddHtlc. This field is set if the htlc is part of a
+	// blinded route.
+	NextBlinding lnwire.BlindingPointRecord
 }

htlcswitch/hop/fuzz_test.go

@@ -117,7 +117,7 @@ func fuzzPayload(f *testing.F, finalPayload bool) {
 
 		r := bytes.NewReader(data)
 
-		payload1, err := NewPayloadFromReader(r, finalPayload)
+		payload1, _, err := NewPayloadFromReader(r, finalPayload)
 		if err != nil {
 			return
 		}
@@ -146,7 +146,7 @@ func fuzzPayload(f *testing.F, finalPayload bool) {
 			require.NoError(t, err)
 		}
 
-		payload2, err := NewPayloadFromReader(&b, finalPayload)
+		payload2, _, err := NewPayloadFromReader(&b, finalPayload)
 		require.NoError(t, err)
 
 		require.Equal(t, payload1, payload2)