htlcswitch+routing+routerrpc: return error source as index

htlcswitch/failure.go

@@ -6,17 +6,18 @@ import (
 	"io"
 
 	"github.com/btcsuite/btcd/btcec"
-	"github.com/lightningnetwork/lightning-onion"
+	sphinx "github.com/lightningnetwork/lightning-onion"
 	"github.com/lightningnetwork/lnd/lnwire"
 )
 
 // ForwardingError wraps an lnwire.FailureMessage in a struct that also
 // includes the source of the error.
 type ForwardingError struct {
-	// ErrorSource is the public key of the node that sent the error. With
-	// this information, the dispatcher of a payment can modify their set
-	// of candidate routes in response to the type of error extracted.
-	ErrorSource *btcec.PublicKey
+	// FailureSourceIdx is the index of the node that sent the failure. With
+	// this information, the dispatcher of a payment can modify their set of
+	// candidate routes in response to the type of failure extracted. Index
+	// zero is the self node.
+	FailureSourceIdx int
 
 	// ExtraMsg is an additional error message that callers can provide in
 	// order to provide context specific error details.
@@ -256,20 +257,20 @@ type SphinxErrorDecrypter struct {
 // NOTE: Part of the ErrorDecrypter interface.
 func (s *SphinxErrorDecrypter) DecryptError(reason lnwire.OpaqueReason) (*ForwardingError, error) {
 
-	source, failureData, err := s.OnionErrorDecrypter.DecryptError(reason)
+	failure, err := s.OnionErrorDecrypter.DecryptError(reason)
 	if err != nil {
 		return nil, err
 	}
 
-	r := bytes.NewReader(failureData)
+	r := bytes.NewReader(failure.Message)
 	failureMsg, err := lnwire.DecodeFailure(r, 0)
 	if err != nil {
 		return nil, err
 	}
 
 	return &ForwardingError{
-		ErrorSource:    source,
-		FailureMessage: failureMsg,
+		FailureSourceIdx: failure.SenderIdx,
+		FailureMessage:   failureMsg,
 	}, nil
 }
 

htlcswitch/mock.go

@@ -163,10 +163,7 @@ func initSwitchWithDB(startingHeight uint32, db *channeldb.DB) (*Switch, error)
 		}
 	}
 
-	priv, _ := btcec.NewPrivateKey(btcec.S256())
-	pubkey := priv.PubKey()
 	cfg := Config{
-		SelfKey:        pubkey,
 		DB:             db,
 		SwitchPackager: channeldb.NewSwitchPackager(),
 		FwdingLog: &mockForwardingLog{
@@ -393,12 +390,9 @@ func (o *mockDeobfuscator) DecryptError(reason lnwire.OpaqueReason) (*Forwarding
 		return nil, err
 	}
 
-	priv, _ := btcec.NewPrivateKey(btcec.S256())
-	pubkey := priv.PubKey()
-
 	return &ForwardingError{
-		ErrorSource:    pubkey,
-		FailureMessage: failure,
+		FailureSourceIdx: 1,
+		FailureMessage:   failure,
 	}, nil
 }
 

htlcswitch/switch.go

@@ -9,7 +9,6 @@ import (
 	"sync/atomic"
 	"time"
 
-	"github.com/btcsuite/btcd/btcec"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcutil"
 	"github.com/coreos/bbolt"
@@ -112,11 +111,6 @@ type ChanClose struct {
 // Config defines the configuration for the service. ALL elements within the
 // configuration MUST be non-nil for the service to carry out its duties.
 type Config struct {
-	// SelfKey is the key of the backing Lightning node. This key is used
-	// to properly craft failure messages, such that the Layer 3 router can
-	// properly route around link./vertex failures.
-	SelfKey *btcec.PublicKey
-
 	// FwdingLog is an interface that will be used by the switch to log
 	// forwarding events. A forwarding event happens each time a payment
 	// circuit is successfully completed. So when we forward an HTLC, and a
@@ -776,8 +770,8 @@ func (s *Switch) handleLocalDispatch(pkt *htlcPacket) error {
 		if err != nil {
 			log.Errorf("Link %v not found", pkt.outgoingChanID)
 			return &ForwardingError{
-				ErrorSource:    s.cfg.SelfKey,
-				FailureMessage: &lnwire.FailUnknownNextPeer{},
+				FailureSourceIdx: 0,
+				FailureMessage:   &lnwire.FailUnknownNextPeer{},
 			}
 		}
 
@@ -790,9 +784,9 @@ func (s *Switch) handleLocalDispatch(pkt *htlcPacket) error {
 			// will be returned back to the router.
 			htlcErr := lnwire.NewTemporaryChannelFailure(nil)
 			return &ForwardingError{
-				ErrorSource:    s.cfg.SelfKey,
-				ExtraMsg:       err.Error(),
-				FailureMessage: htlcErr,
+				FailureSourceIdx: 0,
+				ExtraMsg:         err.Error(),
+				FailureMessage:   htlcErr,
 			}
 		}
 
@@ -808,8 +802,8 @@ func (s *Switch) handleLocalDispatch(pkt *htlcPacket) error {
 				"satisfied", pkt.outgoingChanID)
 
 			return &ForwardingError{
-				ErrorSource:    s.cfg.SelfKey,
-				FailureMessage: htlcErr,
+				FailureSourceIdx: 0,
+				FailureMessage:   htlcErr,
 			}
 		}
 
@@ -823,9 +817,9 @@ func (s *Switch) handleLocalDispatch(pkt *htlcPacket) error {
 			// will be returned back to the router.
 			htlcErr := lnwire.NewTemporaryChannelFailure(nil)
 			return &ForwardingError{
-				ErrorSource:    s.cfg.SelfKey,
-				ExtraMsg:       err.Error(),
-				FailureMessage: htlcErr,
+				FailureSourceIdx: 0,
+				ExtraMsg:         err.Error(),
+				FailureMessage:   htlcErr,
 			}
 		}
 
@@ -967,9 +961,9 @@ func (s *Switch) parseFailedPayment(deobfuscator ErrorDecrypter,
 			failureMsg = lnwire.NewTemporaryChannelFailure(nil)
 		}
 		failure = &ForwardingError{
-			ErrorSource:    s.cfg.SelfKey,
-			ExtraMsg:       userErr,
-			FailureMessage: failureMsg,
+			FailureSourceIdx: 0,
+			ExtraMsg:         userErr,
+			FailureMessage:   failureMsg,
 		}
 
 	// A payment had to be timed out on chain before it got past
@@ -981,9 +975,9 @@ func (s *Switch) parseFailedPayment(deobfuscator ErrorDecrypter,
 			"on-chain, then cancelled back (hash=%v, pid=%d)",
 			paymentHash, paymentID)
 		failure = &ForwardingError{
-			ErrorSource:    s.cfg.SelfKey,
-			ExtraMsg:       userErr,
-			FailureMessage: lnwire.FailPermanentChannelFailure{},
+			FailureSourceIdx: 0,
+			ExtraMsg:         userErr,
+			FailureMessage:   lnwire.FailPermanentChannelFailure{},
 		}
 
 	// A regular multi-hop payment error that we'll need to
@@ -999,9 +993,9 @@ func (s *Switch) parseFailedPayment(deobfuscator ErrorDecrypter,
 				paymentHash, paymentID, err)
 			log.Error(userErr)
 			failure = &ForwardingError{
-				ErrorSource:    s.cfg.SelfKey,
-				ExtraMsg:       userErr,
-				FailureMessage: lnwire.NewTemporaryChannelFailure(nil),
+				FailureSourceIdx: 0,
+				ExtraMsg:         userErr,
+				FailureMessage:   lnwire.NewTemporaryChannelFailure(nil),
 			}
 		}
 	}