lnwallet: prevent static fee estimator fees from being modified

Modifying the static fees is not thread safe. In this commit the fees
are made immutable.

breacharbiter_test.go

@@ -1336,7 +1336,7 @@ func createTestArbiter(t *testing.T, contractBreaches chan *ContractBreachEvent,
 	ba := newBreachArbiter(&BreachConfig{
 		CloseLink:          func(_ *wire.OutPoint, _ htlcswitch.ChannelCloseType) {},
 		DB:                 db,
-		Estimator:          &lnwallet.StaticFeeEstimator{FeePerKW: 12500},
+		Estimator:          lnwallet.NewStaticFeeEstimator(12500, 0),
 		GenSweepScript:     func() ([]byte, error) { return nil, nil },
 		ContractBreaches:   contractBreaches,
 		Signer:             signer,
@@ -1476,7 +1476,7 @@ func createInitChannels(revocationWindow int) (*lnwallet.LightningChannel, *lnwa
 		return nil, nil, nil, err
 	}
 
-	estimator := &lnwallet.StaticFeeEstimator{FeePerKW: 12500}
+	estimator := lnwallet.NewStaticFeeEstimator(12500, 0)
 	feePerKw, err := estimator.EstimateFeePerKW(1)
 	if err != nil {
 		return nil, nil, nil, err

chainregistry.go

@@ -150,9 +150,9 @@ func newChainControlFromConfig(cfg *config, chanDB *channeldb.DB,
 			FeeRate:       cfg.Bitcoin.FeeRate,
 			TimeLockDelta: cfg.Bitcoin.TimeLockDelta,
 		}
-		cc.feeEstimator = lnwallet.StaticFeeEstimator{
+		cc.feeEstimator = lnwallet.NewStaticFeeEstimator(
-			FeePerKW: defaultBitcoinStaticFeePerKW,
+			defaultBitcoinStaticFeePerKW, 0,
-		}
+		)
 	case litecoinChain:
 		cc.routingPolicy = htlcswitch.ForwardingPolicy{
 			MinHTLC:       cfg.Litecoin.MinHTLC,
@@ -160,9 +160,9 @@ func newChainControlFromConfig(cfg *config, chanDB *channeldb.DB,
 			FeeRate:       cfg.Litecoin.FeeRate,
 			TimeLockDelta: cfg.Litecoin.TimeLockDelta,
 		}
-		cc.feeEstimator = lnwallet.StaticFeeEstimator{
+		cc.feeEstimator = lnwallet.NewStaticFeeEstimator(
-			FeePerKW: defaultLitecoinStaticFeePerKW,
+			defaultLitecoinStaticFeePerKW, 0,
-		}
+		)
 	default:
 		return nil, nil, fmt.Errorf("Default routing policy for "+
 			"chain %v is unknown", registeredChains.PrimaryChain())

fundingmanager_test.go

@@ -231,7 +231,7 @@ func createTestFundingManager(t *testing.T, privKey *btcec.PrivateKey,
 	addr *lnwire.NetAddress, tempTestDir string) (*testNode, error) {
 
 	netParams := activeNetParams.Params
-	estimator := lnwallet.StaticFeeEstimator{FeePerKW: 62500}
+	estimator := lnwallet.NewStaticFeeEstimator(62500, 0)
 
 	chainNotifier := &mockNotifier{
 		oneConfChannel: make(chan *chainntnfs.TxConfirmation, 1),

htlcswitch/link_test.go

@@ -1795,7 +1795,7 @@ func TestChannelLinkBandwidthConsistency(t *testing.T) {
 	coreLink.cfg.HodlMask = hodl.MaskFromFlags(hodl.ExitSettle)
 	coreLink.cfg.DebugHTLC = true
 
-	estimator := &lnwallet.StaticFeeEstimator{FeePerKW: 6000}
+	estimator := lnwallet.NewStaticFeeEstimator(6000, 0)
 	feePerKw, err := estimator.EstimateFeePerKW(1)
 	if err != nil {
 		t.Fatalf("unable to query fee estimator: %v", err)
@@ -2206,7 +2206,7 @@ func TestChannelLinkBandwidthConsistencyOverflow(t *testing.T) {
 		aliceMsgs              = coreLink.cfg.Peer.(*mockPeer).sentMsgs
 	)
 
-	estimator := &lnwallet.StaticFeeEstimator{FeePerKW: 6000}
+	estimator := lnwallet.NewStaticFeeEstimator(6000, 0)
 	feePerKw, err := estimator.EstimateFeePerKW(1)
 	if err != nil {
 		t.Fatalf("unable to query fee estimator: %v", err)
@@ -2453,7 +2453,7 @@ func TestChannelLinkTrimCircuitsPending(t *testing.T) {
 
 	// Compute the static fees that will be used to determine the
 	// correctness of Alice's bandwidth when forwarding HTLCs.
-	estimator := &lnwallet.StaticFeeEstimator{FeePerKW: 6000}
+	estimator := lnwallet.NewStaticFeeEstimator(6000, 0)
 	feePerKw, err := estimator.EstimateFeePerKW(1)
 	if err != nil {
 		t.Fatalf("unable to query fee estimator: %v", err)
@@ -2731,7 +2731,7 @@ func TestChannelLinkTrimCircuitsNoCommit(t *testing.T) {
 
 	// Compute the static fees that will be used to determine the
 	// correctness of Alice's bandwidth when forwarding HTLCs.
-	estimator := &lnwallet.StaticFeeEstimator{FeePerKW: 6000}
+	estimator := lnwallet.NewStaticFeeEstimator(6000, 0)
 	feePerKw, err := estimator.EstimateFeePerKW(1)
 	if err != nil {
 		t.Fatalf("unable to query fee estimator: %v", err)
@@ -2989,7 +2989,7 @@ func TestChannelLinkBandwidthChanReserve(t *testing.T) {
 		aliceMsgs              = coreLink.cfg.Peer.(*mockPeer).sentMsgs
 	)
 
-	estimator := &lnwallet.StaticFeeEstimator{FeePerKW: 6000}
+	estimator := lnwallet.NewStaticFeeEstimator(6000, 0)
 	feePerKw, err := estimator.EstimateFeePerKW(1)
 	if err != nil {
 		t.Fatalf("unable to query fee estimator: %v", err)

htlcswitch/test_utils.go

@@ -273,7 +273,7 @@ func createTestChannel(alicePrivKey, bobPrivKey []byte,
 		return nil, nil, nil, nil, err
 	}
 
-	estimator := &lnwallet.StaticFeeEstimator{FeePerKW: 6000}
+	estimator := lnwallet.NewStaticFeeEstimator(6000, 0)
 	feePerKw, err := estimator.EstimateFeePerKW(1)
 	if err != nil {
 		return nil, nil, nil, nil, err

lnwallet/channel_test.go

@@ -1131,7 +1131,7 @@ func TestHTLCSigNumber(t *testing.T) {
 	}
 
 	// Calculate two values that will be below and above Bob's dust limit.
-	estimator := &StaticFeeEstimator{FeePerKW: 6000}
+	estimator := NewStaticFeeEstimator(6000, 0)
 	feePerKw, err := estimator.EstimateFeePerKW(1)
 	if err != nil {
 		t.Fatalf("unable to get fee: %v", err)

lnwallet/fee_estimator.go

@@ -68,22 +68,33 @@ type FeeEstimator interface {
 
 // StaticFeeEstimator will return a static value for all fee calculation
 // requests. It is designed to be replaced by a proper fee calculation
-// implementation.
+// implementation. The fees are not accessible directly, because changing them
+// would not be thread safe.
 type StaticFeeEstimator struct {
-	// FeePerKW is the static fee rate in satoshis-per-vbyte that will be
+	// feePerKW is the static fee rate in satoshis-per-vbyte that will be
 	// returned by this fee estimator.
-	FeePerKW SatPerKWeight
+	feePerKW SatPerKWeight
 
-	// RelayFee is the minimum fee rate required for transactions to be
+	// relayFee is the minimum fee rate required for transactions to be
 	// relayed.
-	RelayFee SatPerKWeight
+	relayFee SatPerKWeight
+}
+
+// NewStaticFeeEstimator returns a new static fee estimator instance.
+func NewStaticFeeEstimator(feePerKW,
+	relayFee SatPerKWeight) *StaticFeeEstimator {
+
+	return &StaticFeeEstimator{
+		feePerKW: feePerKW,
+		relayFee: relayFee,
+	}
 }
 
 // EstimateFeePerKW will return a static value for fee calculations.
 //
 // NOTE: This method is part of the FeeEstimator interface.
 func (e StaticFeeEstimator) EstimateFeePerKW(numBlocks uint32) (SatPerKWeight, error) {
-	return e.FeePerKW, nil
+	return e.feePerKW, nil
 }
 
 // RelayFeePerKW returns the minimum fee rate required for transactions to be
@@ -91,7 +102,7 @@ func (e StaticFeeEstimator) EstimateFeePerKW(numBlocks uint32) (SatPerKWeight, e
 //
 // NOTE: This method is part of the FeeEstimator interface.
 func (e StaticFeeEstimator) RelayFeePerKW() SatPerKWeight {
-	return e.RelayFee
+	return e.relayFee
 }
 
 // Start signals the FeeEstimator to start any processes or goroutines

lnwallet/fee_estimator_test.go

@@ -74,9 +74,7 @@ func TestStaticFeeEstimator(t *testing.T) {
 
 	const feePerKw = lnwallet.FeePerKwFloor
 
-	feeEstimator := &lnwallet.StaticFeeEstimator{
+	feeEstimator := lnwallet.NewStaticFeeEstimator(feePerKw, 0)
-		FeePerKW: feePerKw,
-	}
 	if err := feeEstimator.Start(); err != nil {
 		t.Fatalf("unable to start fee estimator: %v", err)
 	}

lnwallet/interface_test.go

@@ -368,7 +368,7 @@ func createTestWallet(tempTestDir string, miningNode *rpctest.Harness,
 		WalletController: wc,
 		Signer:           signer,
 		ChainIO:          bio,
-		FeeEstimator:     lnwallet.StaticFeeEstimator{FeePerKW: 2500},
+		FeeEstimator:     lnwallet.NewStaticFeeEstimator(2500, 0),
 		DefaultConstraints: channeldb.ChannelConstraints{
 			DustLimit:        500,
 			MaxPendingAmount: lnwire.NewMSatFromSatoshis(btcutil.SatoshiPerBitcoin) * 100,
@@ -2440,7 +2440,7 @@ func runTests(t *testing.T, walletDriver *lnwallet.WalletDriver,
 			}
 
 		case "neutrino":
-			feeEstimator = lnwallet.StaticFeeEstimator{FeePerKW: 62500}
+			feeEstimator = lnwallet.NewStaticFeeEstimator(62500, 0)
 
 			// Set some package-level variable to speed up
 			// operation for tests.

lnwallet/test_utils.go

@@ -229,7 +229,7 @@ func CreateTestChannels() (*LightningChannel, *LightningChannel, func(), error)
 		return nil, nil, nil, err
 	}
 
-	estimator := &StaticFeeEstimator{FeePerKW: 6000}
+	estimator := NewStaticFeeEstimator(6000, 0)
 	feePerKw, err := estimator.EstimateFeePerKW(1)
 	if err != nil {
 		return nil, nil, nil, err

peer_test.go

@@ -157,7 +157,7 @@ func TestPeerChannelClosureAcceptFeeInitiator(t *testing.T) {
 			dummyDeliveryScript),
 	}
 
-	estimator := lnwallet.StaticFeeEstimator{FeePerKW: 12500}
+	estimator := lnwallet.NewStaticFeeEstimator(12500, 0)
 	feePerKw, err := estimator.EstimateFeePerKW(1)
 	if err != nil {
 		t.Fatalf("unable to query fee estimator: %v", err)
@@ -447,7 +447,7 @@ func TestPeerChannelClosureFeeNegotiationsInitiator(t *testing.T) {
 		msg: respShutdown,
 	}
 
-	estimator := lnwallet.StaticFeeEstimator{FeePerKW: 12500}
+	estimator := lnwallet.NewStaticFeeEstimator(12500, 0)
 	initiatorIdealFeeRate, err := estimator.EstimateFeePerKW(1)
 	if err != nil {
 		t.Fatalf("unable to query fee estimator: %v", err)

test_utils.go

@@ -202,7 +202,7 @@ func createTestPeer(notifier chainntnfs.ChainNotifier,
 		return nil, nil, nil, nil, err
 	}
 
-	estimator := &lnwallet.StaticFeeEstimator{FeePerKW: 12500}
+	estimator := lnwallet.NewStaticFeeEstimator(12500, 0)
 	feePerKw, err := estimator.EstimateFeePerKW(1)
 	if err != nil {
 		return nil, nil, nil, nil, err