htlcswitch: refactor dust handling to use ChannelParty

Author: ProofOfKeags

htlcswitch/interfaces.go

@@ -63,7 +63,7 @@ type dustHandler interface {
 	// getDustSum returns the dust sum on either the local or remote
 	// commitment. An optional fee parameter can be passed in which is used
 	// to calculate the dust sum.
-	getDustSum(remote bool,
+	getDustSum(whoseCommit lntypes.ChannelParty,
 		fee fn.Option[chainfee.SatPerKWeight]) lnwire.MilliSatoshi
 
 	// getFeeRate returns the current channel feerate.

htlcswitch/link.go

@@ -2727,15 +2727,10 @@ func (l *channelLink) MayAddOutgoingHtlc(amt lnwire.MilliSatoshi) error {
 // method.
 //
 // NOTE: Part of the dustHandler interface.
-func (l *channelLink) getDustSum(remote bool,
+func (l *channelLink) getDustSum(whoseCommit lntypes.ChannelParty,
 	dryRunFee fn.Option[chainfee.SatPerKWeight]) lnwire.MilliSatoshi {
 
-	party := lntypes.Local
-	if remote {
-		party = lntypes.Remote
-	}
-
-	return l.channel.GetDustSum(party, dryRunFee)
+	return l.channel.GetDustSum(whoseCommit, dryRunFee)
 }
 
 // getFeeRate is a wrapper method that retrieves the underlying channel's
@@ -2789,8 +2784,8 @@ func (l *channelLink) exceedsFeeExposureLimit(
 
 	// Get the sum of dust for both the local and remote commitments using
 	// this "dry-run" fee.
-	localDustSum := l.getDustSum(false, dryRunFee)
-	remoteDustSum := l.getDustSum(true, dryRunFee)
+	localDustSum := l.getDustSum(lntypes.Local, dryRunFee)
+	remoteDustSum := l.getDustSum(lntypes.Remote, dryRunFee)
 
 	// Calculate the local and remote commitment fees using this dry-run
 	// fee.
@@ -2831,12 +2826,16 @@ func (l *channelLink) isOverexposedWithHtlc(htlc *lnwire.UpdateAddHTLC,
 	amount := htlc.Amount.ToSatoshis()
 
 	// See if this HTLC is dust on both the local and remote commitments.
-	isLocalDust := dustClosure(feeRate, incoming, true, amount)
-	isRemoteDust := dustClosure(feeRate, incoming, false, amount)
+	isLocalDust := dustClosure(feeRate, incoming, lntypes.Local, amount)
+	isRemoteDust := dustClosure(feeRate, incoming, lntypes.Remote, amount)
 
 	// Calculate the dust sum for the local and remote commitments.
-	localDustSum := l.getDustSum(false, fn.None[chainfee.SatPerKWeight]())
-	remoteDustSum := l.getDustSum(true, fn.None[chainfee.SatPerKWeight]())
+	localDustSum := l.getDustSum(
+		lntypes.Local, fn.None[chainfee.SatPerKWeight](),
+	)
+	remoteDustSum := l.getDustSum(
+		lntypes.Remote, fn.None[chainfee.SatPerKWeight](),
+	)
 
 	// Grab the larger of the local and remote commitment fees w/o dust.
 	commitFee := l.getCommitFee(false)
@@ -2887,25 +2886,26 @@ func (l *channelLink) isOverexposedWithHtlc(htlc *lnwire.UpdateAddHTLC,
 // the HTLC is incoming (i.e. one that the remote sent), a boolean denoting
 // whether to evaluate on the local or remote commit, and finally an HTLC
 // amount to test.
-type dustClosure func(chainfee.SatPerKWeight, bool, bool, btcutil.Amount) bool
+type dustClosure func(feerate chainfee.SatPerKWeight, incoming bool,
+	whoseCommit lntypes.ChannelParty, amt btcutil.Amount) bool
 
 // dustHelper is used to construct the dustClosure.
 func dustHelper(chantype channeldb.ChannelType, localDustLimit,
 	remoteDustLimit btcutil.Amount) dustClosure {
 
-	isDust := func(feerate chainfee.SatPerKWeight, incoming,
-		localCommit bool, amt btcutil.Amount) bool {
+	isDust := func(feerate chainfee.SatPerKWeight, incoming bool,
+		whoseCommit lntypes.ChannelParty, amt btcutil.Amount) bool {
 
-		if localCommit {
-			return lnwallet.HtlcIsDust(
-				chantype, incoming, lntypes.Local, feerate, amt,
-				localDustLimit,
-			)
+		var dustLimit btcutil.Amount
+		if whoseCommit.IsLocal() {
+			dustLimit = localDustLimit
+		} else {
+			dustLimit = remoteDustLimit
 		}
 
 		return lnwallet.HtlcIsDust(
-			chantype, incoming, lntypes.Remote, feerate, amt,
-			remoteDustLimit,
+			chantype, incoming, whoseCommit, feerate, amt,
+			dustLimit,
 		)
 	}
 

htlcswitch/mailbox.go

@@ -9,6 +9,7 @@ import (
 	"time"
 
 	"github.com/lightningnetwork/lnd/clock"
+	"github.com/lightningnetwork/lnd/lntypes"
 	"github.com/lightningnetwork/lnd/lnwallet/chainfee"
 	"github.com/lightningnetwork/lnd/lnwire"
 )
@@ -660,15 +661,17 @@ func (m *memoryMailBox) DustPackets() (lnwire.MilliSatoshi,
 
 		// Evaluate whether this HTLC is dust on the local commitment.
 		if m.isDust(
-			m.feeRate, false, true, addPkt.amount.ToSatoshis(),
+			m.feeRate, false, lntypes.Local,
+			addPkt.amount.ToSatoshis(),
 		) {
 
 			localDustSum += addPkt.amount
 		}
 
 		// Evaluate whether this HTLC is dust on the remote commitment.
 		if m.isDust(
-			m.feeRate, false, false, addPkt.amount.ToSatoshis(),
+			m.feeRate, false, lntypes.Remote,
+			addPkt.amount.ToSatoshis(),
 		) {
 
 			remoteDustSum += addPkt.amount

htlcswitch/mock.go

@@ -814,7 +814,7 @@ func (f *mockChannelLink) handleSwitchPacket(pkt *htlcPacket) error {
 	return nil
 }
 
-func (f *mockChannelLink) getDustSum(remote bool,
+func (f *mockChannelLink) getDustSum(whoseCommit lntypes.ChannelParty,
 	dryRunFee fn.Option[chainfee.SatPerKWeight]) lnwire.MilliSatoshi {
 
 	return 0

htlcswitch/switch.go

@@ -2788,8 +2788,12 @@ func (s *Switch) dustExceedsFeeThreshold(link ChannelLink,
 	isDust := link.getDustClosure()
 
 	// Evaluate if the HTLC is dust on either sides' commitment.
-	isLocalDust := isDust(feeRate, incoming, true, amount.ToSatoshis())
-	isRemoteDust := isDust(feeRate, incoming, false, amount.ToSatoshis())
+	isLocalDust := isDust(
+		feeRate, incoming, lntypes.Local, amount.ToSatoshis(),
+	)
+	isRemoteDust := isDust(
+		feeRate, incoming, lntypes.Remote, amount.ToSatoshis(),
+	)
 
 	if !(isLocalDust || isRemoteDust) {
 		// If the HTLC is not dust on either commitment, it's fine to
@@ -2807,7 +2811,7 @@ func (s *Switch) dustExceedsFeeThreshold(link ChannelLink,
 	// sum for it.
 	if isLocalDust {
 		localSum := link.getDustSum(
-			false, fn.None[chainfee.SatPerKWeight](),
+			lntypes.Local, fn.None[chainfee.SatPerKWeight](),
 		)
 		localSum += localMailDust
 
@@ -2827,7 +2831,7 @@ func (s *Switch) dustExceedsFeeThreshold(link ChannelLink,
 	// reached this point.
 	if isRemoteDust {
 		remoteSum := link.getDustSum(
-			true, fn.None[chainfee.SatPerKWeight](),
+			lntypes.Remote, fn.None[chainfee.SatPerKWeight](),
 		)
 		remoteSum += remoteMailDust
 

htlcswitch/switch_test.go

@@ -4319,7 +4319,7 @@ func TestSwitchDustForwarding(t *testing.T) {
 	}
 
 	checkAlmostDust := func(link *channelLink, mbox MailBox,
-		remote bool) bool {
+		whoseCommit lntypes.ChannelParty) bool {
 
 		timeout := time.After(15 * time.Second)
 		pollInterval := 300 * time.Millisecond
@@ -4335,12 +4335,12 @@ func TestSwitchDustForwarding(t *testing.T) {
 			}
 
 			linkDust := link.getDustSum(
-				remote, fn.None[chainfee.SatPerKWeight](),
+				whoseCommit, fn.None[chainfee.SatPerKWeight](),
 			)
 			localMailDust, remoteMailDust := mbox.DustPackets()
 
 			totalDust := linkDust
-			if remote {
+			if whoseCommit.IsRemote() {
 				totalDust += remoteMailDust
 			} else {
 				totalDust += localMailDust
@@ -4359,7 +4359,11 @@ func TestSwitchDustForwarding(t *testing.T) {
 		n.firstBobChannelLink.ChanID(),
 		n.firstBobChannelLink.ShortChanID(),
 	)
-	require.True(t, checkAlmostDust(n.firstBobChannelLink, bobMbox, false))
+	require.True(
+		t, checkAlmostDust(
+			n.firstBobChannelLink, bobMbox, lntypes.Local,
+		),
+	)
 
 	// Sending one more HTLC should fail. SendHTLC won't error, but the
 	// HTLC should be failed backwards.
@@ -4408,7 +4412,9 @@ func TestSwitchDustForwarding(t *testing.T) {
 		aliceBobFirstHop, uint64(bobAttemptID), nondustHtlc,
 	)
 	require.NoError(t, err)
-	require.True(t, checkAlmostDust(n.firstBobChannelLink, bobMbox, false))
+	require.True(t, checkAlmostDust(
+		n.firstBobChannelLink, bobMbox, lntypes.Local,
+	))
 
 	// Check that the HTLC failed.
 	bobResultChan, err = n.bobServer.htlcSwitch.GetAttemptResult(
@@ -4486,7 +4492,11 @@ func TestSwitchDustForwarding(t *testing.T) {
 	aliceMbox := aliceOrch.GetOrCreateMailBox(
 		n.aliceChannelLink.ChanID(), n.aliceChannelLink.ShortChanID(),
 	)
-	require.True(t, checkAlmostDust(n.aliceChannelLink, aliceMbox, true))
+	require.True(
+		t, checkAlmostDust(
+			n.aliceChannelLink, aliceMbox, lntypes.Remote,
+		),
+	)
 
 	err = n.aliceServer.htlcSwitch.SendHTLC(
 		n.aliceChannelLink.ShortChanID(), uint64(aliceAttemptID),