routing+lnrpc: add inbound fee policy update

routing/localchans/manager.go

@@ -112,6 +112,7 @@ func (r *Manager) UpdatePolicy(newSchema routing.ChannelPolicy,
 			TimeLockDelta: uint32(edge.TimeLockDelta),
 			MinHTLCOut:    edge.MinHTLC,
 			MaxHTLC:       edge.MaxHTLC,
+			InboundFee:    newSchema.InboundFee,
 		}
 
 		return nil
@@ -180,6 +181,12 @@ func (r *Manager) updateEdge(tx kvdb.RTx, chanPoint wire.OutPoint,
 	edge.FeeProportionalMillionths = lnwire.MilliSatoshi(
 		newSchema.FeeRate,
 	)
+
+	inboundFee := newSchema.InboundFee.ToWire()
+	if err := edge.ExtraOpaqueData.PackRecords(&inboundFee); err != nil {
+		return err
+	}
+
 	edge.TimeLockDelta = uint16(newSchema.TimeLockDelta)
 
 	// Retrieve negotiated channel htlc amt limits.

routing/router.go

@@ -287,6 +287,10 @@ type FeeSchema struct {
 	// the effective fee rate charged per mSAT will be: (amount *
 	// FeeRate/1,000,000).
 	FeeRate uint32
+
+	// InboundFee is the inbound fee schedule that applies to forwards
+	// coming in through a channel to which this FeeSchema pertains.
+	InboundFee models.InboundFee
 }
 
 // ChannelPolicy holds the parameters that determine the policy we enforce