rpcserver+peer+chancloser: change rbf coop close from sat/vb to sat/kw

Change rbf coop close flow to use sat/kw insted of sat/vb,
and update the unit tests accordingly.

Author: MPins

lnwallet/chancloser/rbf_coop_states.go

@@ -100,7 +100,7 @@ type SendShutdown struct {
 
 	// IdealFeeRate is the ideal fee rate we'd like to use for the closing
 	// attempt.
-	IdealFeeRate chainfee.SatPerVByte
+	IdealFeeRate chainfee.SatPerKWeight
 }
 
 // protocolSealed indicates that this struct is a ProtocolEvent instance.
@@ -182,7 +182,7 @@ func (c *ChannelFlushed) protocolSealed() {}
 //   - toState: LocalOfferSent
 type SendOfferEvent struct {
 	// TargetFeeRate is the fee rate we'll use for the closing transaction.
-	TargetFeeRate chainfee.SatPerVByte
+	TargetFeeRate chainfee.SatPerKWeight
 }
 
 // protocolSealed indicates that this struct is a ProtocolEvent instance.
@@ -304,7 +304,7 @@ type Environment struct {
 	// DefaultFeeRate is the fee we'll use for the closing transaction if
 	// the user didn't specify an ideal fee rate. This may happen if the
 	// remote party is the one that initiates the co-op close.
-	DefaultFeeRate chainfee.SatPerVByte
+	DefaultFeeRate chainfee.SatPerKWeight
 
 	// ThawHeight is the height at which the channel will be thawed. If
 	// this is None, then co-op close can occur at any moment.
@@ -453,7 +453,7 @@ type ShutdownPending struct {
 
 	// IdealFeeRate is the ideal fee rate we'd like to use for the closing
 	// attempt.
-	IdealFeeRate fn.Option[chainfee.SatPerVByte]
+	IdealFeeRate fn.Option[chainfee.SatPerKWeight]
 
 	// EarlyRemoteOffer is the offer we received from the remote party
 	// before we received their shutdown message. We'll stash it to process
@@ -498,7 +498,7 @@ type ChannelFlushing struct {
 	// IdealFeeRate is the ideal fee rate we'd like to use for the closing
 	// transaction. Once the channel has been flushed, we'll use this as
 	// our target fee rate.
-	IdealFeeRate fn.Option[chainfee.SatPerVByte]
+	IdealFeeRate fn.Option[chainfee.SatPerKWeight]
 }
 
 // String returns the name of the state for ChannelFlushing.
@@ -732,7 +732,7 @@ type LocalOfferSent struct {
 	ProposedFee btcutil.Amount
 
 	// ProposedFeeRate is the fee rate we proposed to the remote party.
-	ProposedFeeRate chainfee.SatPerVByte
+	ProposedFeeRate chainfee.SatPerKWeight
 
 	// LocalSig is the signature we sent to the remote party.
 	LocalSig lnwire.Sig
@@ -781,7 +781,7 @@ type ClosePending struct {
 	*CloseChannelTerms
 
 	// FeeRate is the fee rate of the closing transaction.
-	FeeRate chainfee.SatPerVByte
+	FeeRate chainfee.SatPerKWeight
 
 	// Party indicates which party is at this state. This is used to
 	// implement the state transition properly, based on ShouldRouteTo.

lnwallet/chancloser/rbf_coop_test.go

@@ -783,7 +783,7 @@ func newRbfCloserTestHarness(t *testing.T,
 		ChanPoint:             chanPoint,
 		ChanID:                chanID,
 		Scid:                  scid,
-		DefaultFeeRate:        defaultFeeRate.FeePerVByte(),
+		DefaultFeeRate:        defaultFeeRate,
 		ThawHeight:            cfg.thawHeight,
 		RemoteUpfrontShutdown: cfg.remoteUpfrontAddr,
 		LocalUpfrontShutdown:  cfg.localUpfrontAddr,
@@ -854,7 +854,7 @@ func TestRbfChannelActiveTransitions(t *testing.T) {
 	localAddr := lnwire.DeliveryAddress(bytes.Repeat([]byte{0x01}, 20))
 	remoteAddr := lnwire.DeliveryAddress(bytes.Repeat([]byte{0x02}, 20))
 
-	feeRate := chainfee.SatPerVByte(1000)
+	feeRate := chainfee.SatPerKWeight(250_000)
 
 	// Test that if a spend event is received, the FSM transitions to the
 	// CloseFin terminal state.
@@ -1050,7 +1050,7 @@ func TestRbfShutdownPendingTransitions(t *testing.T) {
 	t.Run("initiator_shutdown_recv_ok", func(t *testing.T) {
 		firstState := *startingState
 		firstState.IdealFeeRate = fn.Some(
-			chainfee.FeePerKwFloor.FeePerVByte(),
+			chainfee.FeePerKwFloor,
 		)
 		firstState.ShutdownScripts = ShutdownScripts{
 			LocalDeliveryScript:  localAddr,
@@ -1097,7 +1097,7 @@ func TestRbfShutdownPendingTransitions(t *testing.T) {
 	t.Run("responder_complete", func(t *testing.T) {
 		firstState := *startingState
 		firstState.IdealFeeRate = fn.Some(
-			chainfee.FeePerKwFloor.FeePerVByte(),
+			chainfee.FeePerKwFloor,
 		)
 		firstState.ShutdownScripts = ShutdownScripts{
 			LocalDeliveryScript:  localAddr,
@@ -1128,7 +1128,7 @@ func TestRbfShutdownPendingTransitions(t *testing.T) {
 	t.Run("early_remote_offer_shutdown_complete", func(t *testing.T) {
 		firstState := *startingState
 		firstState.IdealFeeRate = fn.Some(
-			chainfee.FeePerKwFloor.FeePerVByte(),
+			chainfee.FeePerKwFloor,
 		)
 		firstState.ShutdownScripts = ShutdownScripts{
 			LocalDeliveryScript:  localAddr,
@@ -1175,7 +1175,7 @@ func TestRbfShutdownPendingTransitions(t *testing.T) {
 	t.Run("early_remote_offer_shutdown_received", func(t *testing.T) {
 		firstState := *startingState
 		firstState.IdealFeeRate = fn.Some(
-			chainfee.FeePerKwFloor.FeePerVByte(),
+			chainfee.FeePerKwFloor,
 		)
 		firstState.ShutdownScripts = ShutdownScripts{
 			LocalDeliveryScript:  localAddr,
@@ -1433,7 +1433,7 @@ func TestRbfCloseClosingNegotiationLocal(t *testing.T) {
 	}
 
 	sendOfferEvent := &SendOfferEvent{
-		TargetFeeRate: chainfee.FeePerKwFloor.FeePerVByte(),
+		TargetFeeRate: chainfee.FeePerKwFloor,
 	}
 
 	balanceAfterClose := localBalance.ToSatoshis() - absoluteFee
@@ -1614,7 +1614,7 @@ func TestRbfCloseClosingNegotiationLocal(t *testing.T) {
 		// Next, we'll send in a new SendOfferEvent event which
 		// simulates the user requesting a RBF fee bump. We'll use 10x
 		// the fee we used in the last iteration.
-		rbfFeeBump := chainfee.FeePerKwFloor.FeePerVByte() * 10
+		rbfFeeBump := chainfee.FeePerKwFloor * 10
 		localOffer := &SendOfferEvent{
 			TargetFeeRate: rbfFeeBump,
 		}
@@ -1649,7 +1649,7 @@ func TestRbfCloseClosingNegotiationLocal(t *testing.T) {
 		// the amount we have in the channel.
 		closeHarness.expectFeeEstimate(btcutil.SatoshiPerBitcoin, 1)
 
-		rbfFeeBump := chainfee.FeePerKwFloor.FeePerVByte()
+		rbfFeeBump := chainfee.FeePerKwFloor
 		localOffer := &SendOfferEvent{
 			TargetFeeRate: rbfFeeBump,
 		}
@@ -1997,7 +1997,7 @@ func TestRbfCloseErr(t *testing.T) {
 		})
 		defer closeHarness.stopAndAssert()
 
-		rbfFeeBump := chainfee.FeePerKwFloor.FeePerVByte()
+		rbfFeeBump := chainfee.FeePerKwFloor
 		localOffer := &SendOfferEvent{
 			TargetFeeRate: rbfFeeBump,
 		}

lnwallet/chancloser/rbf_coop_transitions.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"fmt"
 
+	"github.com/btcsuite/btcd/blockchain"
 	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/chaincfg"
@@ -509,7 +510,7 @@ func (c *ChannelFlushing) ProcessEvent(event ProtocolEvent,
 		localTxOut, remoteTxOut := closeTerms.DeriveCloseTxOuts()
 		absoluteFee := env.FeeEstimator.EstimateFee(
 			env.ChanType, localTxOut, remoteTxOut,
-			idealFeeRate.FeePerKWeight(),
+			idealFeeRate,
 		)
 
 		chancloserLog.Infof("ChannelPoint(%v): using ideal_fee=%v, "+
@@ -752,7 +753,7 @@ func (l *LocalCloseStart) ProcessEvent(event ProtocolEvent,
 		localTxOut, remoteTxOut := l.DeriveCloseTxOuts()
 		absoluteFee := env.FeeEstimator.EstimateFee(
 			env.ChanType, localTxOut, remoteTxOut,
-			msg.TargetFeeRate.FeePerKWeight(),
+			msg.TargetFeeRate,
 		)
 
 		// If we can't actually pay for fees here, then we'll just do a
@@ -1128,11 +1129,16 @@ func (l *RemoteCloseStart) ProcessEvent(event ProtocolEvent,
 		// We'll also compute the final fee rate that the remote party
 		// paid based off the absolute fee and the size of the closing
 		// transaction.
-		vSize := mempool.GetTxVirtualSize(btcutil.NewTx(closeTx))
-		feeRate := chainfee.SatPerVByte(
-			int64(msg.SigMsg.FeeSatoshis) / vSize,
+		weight := blockchain.GetTransactionWeight(
+			btcutil.NewTx(closeTx),
 		)
 
+		// Convert absolute fee to a fee rate in sat/kw, rounding up.
+		fee := int64(msg.SigMsg.FeeSatoshis)
+		rate := ((fee * 1000) + weight - 1) / weight
+
+		feeRate := chainfee.SatPerKWeight(rate)
+
 		// Now that we've extracted the signature, we'll transition to
 		// the next state where we'll sign+broadcast the sig.
 		return &CloseStateTransition{

peer/brontide.go

@@ -150,10 +150,10 @@ type PendingUpdate struct {
 	// transaction.
 	OutputIndex uint32
 
-	// FeePerVByte is an optional field, that is set only when the new RBF
+	// FeePerKw is an optional field, that is set only when the new RBF
 	// coop close flow is used. This indicates the new closing fee rate on
 	// the closing transaction.
-	FeePerVbyte fn.Option[chainfee.SatPerVByte]
+	FeePerKw fn.Option[chainfee.SatPerKWeight]
 
 	// IsLocalCloseTx is an optional field that indicates if this update is
 	// sent for our local close txn, or the close txn of the remote party.
@@ -3611,7 +3611,7 @@ func (p *Brontide) observeRbfCloseUpdates(chanCloser *chancloser.RbfChanCloser,
 
 	var (
 		lastTxids    lntypes.Dual[chainhash.Hash]
-		lastFeeRates lntypes.Dual[chainfee.SatPerVByte]
+		lastFeeRates lntypes.Dual[chainfee.SatPerKWeight]
 	)
 
 	maybeNotifyTxBroadcast := func(state chancloser.AsymmetricPeerState,
@@ -3670,8 +3670,8 @@ func (p *Brontide) observeRbfCloseUpdates(chanCloser *chancloser.RbfChanCloser,
 		if closeReq != nil && closingTxid != lastTxid {
 			select {
 			case closeReq.Updates <- &PendingUpdate{
-				Txid:        closingTxid[:],
-				FeePerVbyte: fn.Some(closePending.FeeRate),
+				Txid:     closingTxid[:],
+				FeePerKw: fn.Some(closePending.FeeRate),
 				IsLocalCloseTx: fn.Some(
 					party == lntypes.Local,
 				),
@@ -3928,7 +3928,7 @@ func (p *Brontide) initRbfChanCloser(
 		ChanID:         chanID,
 		Scid:           scid,
 		ChanType:       channel.ChanType(),
-		DefaultFeeRate: defaultFeePerKw.FeePerVByte(),
+		DefaultFeeRate: defaultFeePerKw,
 		ThawHeight:     fn.Some(thawHeight),
 		RemoteUpfrontShutdown: ChooseAddr(
 			channel.RemoteUpfrontShutdownScript(),
@@ -4189,7 +4189,7 @@ func (p *Brontide) startRbfChanCloser(shutdown shutdownInit,
 		}
 
 		ctx, _ := p.cg.Create(context.Background())
-		feeRate := defaultFeePerKw.FeePerVByte()
+		feeRate := defaultFeePerKw
 
 		// Depending on the state of the state machine, we'll either
 		// kick things off by sending shutdown, or attempt to send a new

rpcserver.go

@@ -3137,8 +3137,8 @@ func createRPCCloseUpdate(
 		u.IsLocalCloseTx.WhenSome(func(isLocal bool) {
 			upd.LocalCloseTx = isLocal
 		})
-		u.FeePerVbyte.WhenSome(func(feeRate chainfee.SatPerVByte) {
-			upd.FeePerVbyte = int64(feeRate)
+		u.FeePerKw.WhenSome(func(feeRate chainfee.SatPerKWeight) {
+			upd.FeePerKw = uint64(feeRate)
 		})
 
 		return &lnrpc.CloseStatusUpdate{