routing: move unreadable failure handling into mission control

routing/missioncontrol.go

@@ -390,29 +390,40 @@ func (m *MissionControl) GetHistorySnapshot() *MissionControlSnapshot {
 }
 
 // ReportPaymentFail reports a failed payment to mission control as input for
-// future probability estimates. It returns a bool indicating whether this error
+// future probability estimates. The failureSourceIdx argument indicates the
-// is a final error and no further payment attempts need to be made.
+// failure source. If it is nil, the failure source is unknown. This function
+// returns a bool indicating whether this error is a final error. If it is
+// final, a failure reason is returned and no further payment attempts need to
+// be made.
 func (m *MissionControl) ReportPaymentFail(rt *route.Route,
-	failureSourceIdx int, failure lnwire.FailureMessage) (bool,
+	failureSourceIdx *int, failure lnwire.FailureMessage) (bool,
 	channeldb.FailureReason) {
 
-	var (
+	var failureSourceIdxInt int
-		failureVertex route.Vertex
+	if failureSourceIdx == nil {
-	)
+		// If the failure message could not be decrypted, attribute the
+		// failure to our own outgoing channel.
+		//
+		// TODO(joostager): Penalize all channels in the route.
+		failureSourceIdxInt = 0
+		failure = lnwire.NewTemporaryChannelFailure(nil)
+	} else {
+		failureSourceIdxInt = *failureSourceIdx
+	}
 
-	// For any non-self failure, look up the source pub key in the hops
+	var failureVertex route.Vertex
-	// slice. Otherwise return the self node pubkey.
+
-	if failureSourceIdx > 0 {
+	if failureSourceIdxInt > 0 {
-		failureVertex = rt.Hops[failureSourceIdx-1].PubKeyBytes
+		failureVertex = rt.Hops[failureSourceIdxInt-1].PubKeyBytes
 	} else {
 		failureVertex = rt.SourcePubKey
 	}
 	log.Tracef("Node %x (index %v) reported failure when sending htlc",
 		failureVertex, failureSourceIdx)
 
-	// Always determine chan id ourselves, because a channel
+	// Always determine chan id ourselves, because a channel update with id
-	// update with id may not be available.
+	// may not be available.
-	failedEdge, failedAmt := getFailedEdge(rt, failureSourceIdx)
+	failedEdge, failedAmt := getFailedEdge(rt, failureSourceIdxInt)
 
 	switch failure.(type) {
 

routing/missioncontrol_test.go

@@ -78,7 +78,7 @@ func (ctx *mcTestContext) reportFailure(t time.Time,
 
 	errorSourceIdx := 1
 	ctx.mc.ReportPaymentFail(
-		mcTestRoute, errorSourceIdx, failure,
+		mcTestRoute, &errorSourceIdx, failure,
 	)
 }
 

routing/mock_test.go

@@ -99,7 +99,7 @@ type mockMissionControl struct {
 var _ MissionController = (*mockMissionControl)(nil)
 
 func (m *mockMissionControl) ReportPaymentFail(rt *route.Route,
-	failureSourceIdx int, failure lnwire.FailureMessage) (bool,
+	failureSourceIdx *int, failure lnwire.FailureMessage) (bool,
 	channeldb.FailureReason) {
 
 	return false, 0

routing/router.go

@@ -179,7 +179,7 @@ type MissionController interface {
 	// whether this error is a final error and no further payment attempts
 	// need to be made.
 	ReportPaymentFail(rt *route.Route,
-		failureSourceIdx int, failure lnwire.FailureMessage) (bool,
+		failureSourceIdx *int, failure lnwire.FailureMessage) (bool,
 		channeldb.FailureReason)
 
 	// GetEdgeProbability is expected to return the success probability of a
@@ -1893,21 +1893,16 @@ func (r *ChannelRouter) tryApplyChannelUpdate(rt *route.Route,
 // error type, this error is either the final outcome of the payment or we need
 // to continue with an alternative route. This is indicated by the boolean
 // return value.
-func (r *ChannelRouter) processSendError(rt *route.Route, sendErr error) (
+func (r *ChannelRouter) processSendError(rt *route.Route, sendErr error) (bool,
-	bool, channeldb.FailureReason) {
+	channeldb.FailureReason) {
 
-	// If the failure message could not be decrypted, attribute the failure
-	// to our own outgoing channel.
-	//
-	// TODO(joostager): Penalize all channels in the route.
 	if sendErr == htlcswitch.ErrUnreadableFailureMessage {
-		sendErr = &htlcswitch.ForwardingError{
+		log.Tracef("Unreadable failure when sending htlc")
-			FailureSourceIdx: 0,
-			FailureMessage:   lnwire.NewTemporaryChannelFailure(nil),
-		}
-	}
 
-	// If an internal, non-forwarding error occurred, we can stop trying.
+		return r.cfg.MissionControl.ReportPaymentFail(rt, nil, nil)
+	}
+	// If an internal, non-forwarding error occurred, we can stop
+	// trying.
 	fErr, ok := sendErr.(*htlcswitch.ForwardingError)
 	if !ok {
 		return true, channeldb.FailureReasonError
@@ -1927,8 +1922,11 @@ func (r *ChannelRouter) processSendError(rt *route.Route, sendErr error) (
 		}
 	}
 
+	log.Tracef("Node=%v reported failure when sending htlc",
+		failureSourceIdx)
+
 	return r.cfg.MissionControl.ReportPaymentFail(
-		rt, failureSourceIdx, failureMessage,
+		rt, &failureSourceIdx, failureMessage,
 	)
 }