contractcourt: specify deadline and budget for anchor output

contractcourt/anchor_resolver.go

@@ -9,6 +9,7 @@ import (
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/fn"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/sweep"
 )
@@ -118,6 +119,14 @@ func (c *anchorResolver) Resolve() (ContractResolver, error) {
 			Fee: sweep.FeeEstimateInfo{
 				FeeRate: relayFeeRate,
 			},
+			// For normal anchor sweeping, the budget is 330 sats.
+			Budget: btcutil.Amount(
+				anchorInput.SignDesc().Output.Value,
+			),
+
+			// There's no rush to sweep the anchor, so we use a nil
+			// deadline here.
+			DeadlineHeight: fn.None[int32](),
 		},
 	)
 	if err != nil {

contractcourt/channel_arbitrator.go

@@ -37,12 +37,6 @@ var (
 )
 
 const (
-	// anchorSweepConfTarget is the conf target used when sweeping
-	// commitment anchors. This value is only used when the commitment
-	// transaction has no valid HTLCs for determining a confirmation
-	// deadline.
-	anchorSweepConfTarget = 144
-
 	// arbitratorBlockBufferSize is the size of the buffer we give to each
 	// channel arbitrator.
 	arbitratorBlockBufferSize = 20
@@ -1321,36 +1315,23 @@ func (c *ChannelArbitrator) sweepAnchors(anchors *lnwallet.AnchorResolutions,
 		htlcs htlcSet, anchorPath string) error {
 
 		// Find the deadline for this specific anchor.
-		deadlineOpt, _, err := c.findCommitmentDeadlineAndValue(
+		deadline, value, err := c.findCommitmentDeadlineAndValue(
 			heightHint, htlcs,
 		)
 		if err != nil {
 			return err
 		}
 
-		deadline := uint32(1)
-		deadlineOpt.WhenSome(func(d int32) {
-			deadline = uint32(d)
-		})
+		// If we cannot find a deadline, it means there's no HTLCs at
+		// stake, which means we can relax our anchor sweeping as we
+		// don't have any time sensitive outputs to sweep.
+		if deadline.IsNone() {
+			log.Infof("ChannelArbitrator(%v): no HTLCs at stake, "+
+				"skipped anchor CPFP", c.cfg.ChanPoint)
 
-		// Create a force flag that's used to indicate whether we
-		// should force sweeping this anchor.
-		var force bool
-
-		// Check the deadline against the default value. If it's less
-		// than the default value of 144, it means there is a deadline
-		// and we will perform a CPFP for this commitment tx.
-		if deadline < anchorSweepConfTarget {
-			// Signal that this is a force sweep, so that the
-			// anchor will be swept even if it isn't economical
-			// purely based on the anchor value.
-			force = true
+			return nil
 		}
 
-		log.Debugf("ChannelArbitrator(%v): pre-confirmation sweep of "+
-			"anchor of %s commit tx %v, force=%v", c.cfg.ChanPoint,
-			anchorPath, anchor.CommitAnchor, force)
-
 		witnessType := input.CommitmentAnchor
 
 		// For taproot channels, we need to use the proper witness
@@ -1374,6 +1355,28 @@ func (c *ChannelArbitrator) sweepAnchors(anchors *lnwallet.AnchorResolutions,
 			},
 		)
 
+		// If we have a deadline, we'll use it to calculate the
+		// deadline height, otherwise default to none.
+		deadlineDesc := "None"
+		deadlineHeight := fn.MapOption(func(d int32) int32 {
+			deadlineDesc = fmt.Sprintf("%d", d)
+
+			return d + int32(heightHint)
+		})(deadline)
+
+		// Calculate the budget based on the value under protection,
+		// which is the sum of all HTLCs on this commitment subtracted
+		// by their budgets.
+		budget := calculateBudget(
+			value, c.cfg.Budget.AnchorCPFPRatio,
+			c.cfg.Budget.AnchorCPFP,
+		)
+
+		log.Infof("ChannelArbitrator(%v): offering anchor from %s "+
+			"commitment %v to sweeper with deadline=%v, budget=%v",
+			c.cfg.ChanPoint, anchorPath, anchor.CommitAnchor,
+			deadlineDesc, budget)
+
 		// Sweep anchor output with a confirmation target fee
 		// preference. Because this is a cpfp-operation, the anchor
 		// will only be attempted to sweep when the current fee
@@ -1382,11 +1385,9 @@ func (c *ChannelArbitrator) sweepAnchors(anchors *lnwallet.AnchorResolutions,
 		_, err = c.cfg.Sweeper.SweepInput(
 			&anchorInput,
 			sweep.Params{
-				Fee: sweep.FeeEstimateInfo{
-					ConfTarget: deadline,
-				},
-				Force:          force,
 				ExclusiveGroup: &exclusiveGroup,
+				Budget:         budget,
+				DeadlineHeight: deadlineHeight,
 			},
 		)
 		if err != nil {
@@ -2138,6 +2139,20 @@ func (c *ChannelArbitrator) checkRemoteDiffActions(height uint32,
 			continue
 		}
 
+		preimageAvailable, err := c.isPreimageAvailable(htlc.RHash)
+		if err != nil {
+			log.Errorf("ChannelArbitrator(%v): failed to query "+
+				"preimage for dangling htlc=%x from remote "+
+				"commitments diff", c.cfg.ChanPoint,
+				htlc.RHash[:])
+
+			continue
+		}
+
+		if preimageAvailable {
+			continue
+		}
+
 		actionMap[HtlcFailNowAction] = append(
 			actionMap[HtlcFailNowAction], htlc,
 		)

contractcourt/channel_arbitrator_test.go

@@ -391,7 +391,9 @@ func createTestChannelArbitrator(t *testing.T, log ArbitratorLog,
 
 			return nil
 		},
-		Budget: *DefaultBudgetConfig(),
+		Budget:     *DefaultBudgetConfig(),
+		PreimageDB: newMockWitnessBeacon(),
+		Registry:   &mockRegistry{},
 	}
 
 	// We'll use the resolvedChan to synchronize on call to
@@ -2405,6 +2407,8 @@ func TestSweepAnchors(t *testing.T) {
 	htlcIndexBase := uint64(99)
 	htlcExpiryBase := heightHint + uint32(10)
 
+	htlcAmt := lnwire.MilliSatoshi(1_000_000)
+
 	// Create three testing HTLCs.
 	htlcDust := channeldb.HTLC{
 		HtlcIndex:     htlcIndexBase + 1,
@@ -2415,15 +2419,17 @@ func TestSweepAnchors(t *testing.T) {
 		HtlcIndex:     htlcIndexBase + 2,
 		RefundTimeout: htlcExpiryBase + 2,
 		RHash:         rHash,
+		Amt:           htlcAmt,
 	}
 	htlcSmallExipry := channeldb.HTLC{
 		HtlcIndex:     htlcIndexBase + 3,
 		RefundTimeout: htlcExpiryBase + 3,
+		Amt:           htlcAmt,
 	}
 
 	// Setup our local HTLC set such that we will use the HTLC's CLTV from
 	// the incoming HTLC set.
-	expectedLocalDeadline := htlcWithPreimage.RefundTimeout - heightHint
+	expectedLocalDeadline := htlcWithPreimage.RefundTimeout
 	chanArb.activeHTLCs[LocalHtlcSet] = htlcSet{
 		incomingHTLCs: map[uint64]channeldb.HTLC{
 			htlcWithPreimage.HtlcIndex: htlcWithPreimage,
@@ -2442,8 +2448,7 @@ func TestSweepAnchors(t *testing.T) {
 	}
 
 	// Setup our remote HTLC set such that no valid HTLCs can be used, thus
-	// we default to anchorSweepConfTarget.
-	expectedRemoteDeadline := anchorSweepConfTarget
+	// the anchor sweeping is skipped.
 	chanArb.activeHTLCs[RemoteHtlcSet] = htlcSet{
 		incomingHTLCs: map[uint64]channeldb.HTLC{
 			htlcSmallExipry.HtlcIndex: htlcSmallExipry,
@@ -2463,7 +2468,7 @@ func TestSweepAnchors(t *testing.T) {
 
 	// Setup out pending remote HTLC set such that we will use the HTLC's
 	// CLTV from the outgoing HTLC set.
-	expectedPendingDeadline := htlcSmallExipry.RefundTimeout - heightHint
+	expectedPendingDeadline := htlcSmallExipry.RefundTimeout
 	chanArb.activeHTLCs[RemotePendingHtlcSet] = htlcSet{
 		incomingHTLCs: map[uint64]channeldb.HTLC{
 			htlcDust.HtlcIndex: htlcDust,
@@ -2506,20 +2511,22 @@ func TestSweepAnchors(t *testing.T) {
 
 	// Verify deadlines are used as expected.
 	deadlines := chanArbCtx.sweeper.deadlines
+
+	// We should see two `SweepInput` calls.
+	require.Len(t, deadlines, 2)
+
 	// Since there's no guarantee of the deadline orders, we sort it here
 	// so they can be compared.
-	sort.Ints(deadlines) // [12, 13, 144]
+	sort.Ints(deadlines) // [12, 13]
 	require.EqualValues(
 		t, expectedLocalDeadline, deadlines[0],
-		"local deadline not matched",
+		"local deadline not matched, want %v, got %v",
+		expectedLocalDeadline, deadlines[0],
 	)
 	require.EqualValues(
 		t, expectedPendingDeadline, deadlines[1],
-		"pending remote deadline not matched",
-	)
-	require.EqualValues(
-		t, expectedRemoteDeadline, deadlines[2],
-		"remote deadline not matched",
+		"pending remote deadline not matched, want %v, got %v",
+		expectedPendingDeadline, deadlines[1],
 	)
 }
 
@@ -2582,6 +2589,8 @@ func TestChannelArbitratorAnchors(t *testing.T) {
 	heightHint := uint32(1000)
 	chanArbCtx.chanArb.blocks <- int32(heightHint)
 
+	htlcAmt := lnwire.MilliSatoshi(1_000_000)
+
 	// Create testing HTLCs.
 	htlcExpiryBase := heightHint + uint32(10)
 	htlcWithPreimage := channeldb.HTLC{
@@ -2589,10 +2598,12 @@ func TestChannelArbitratorAnchors(t *testing.T) {
 		RefundTimeout: htlcExpiryBase + 2,
 		RHash:         rHash,
 		Incoming:      true,
+		Amt:           htlcAmt,
 	}
 	htlc := channeldb.HTLC{
 		HtlcIndex:     100,
 		RefundTimeout: htlcExpiryBase + 3,
+		Amt:           htlcAmt,
 	}
 
 	// We now send two HTLC updates, one for local HTLC set and the other
@@ -2600,9 +2611,9 @@ func TestChannelArbitratorAnchors(t *testing.T) {
 	newUpdate := &ContractUpdate{
 		HtlcKey: LocalHtlcSet,
 		// This will make the deadline of the local anchor resolution
-		// to be htlcWithPreimage's CLTV minus heightHint since the
-		// incoming HTLC (toLocalHTLCs) has a lower CLTV value and is
-		// preimage available.
+		// to be htlcWithPreimage's CLTV since the incoming HTLC
+		// (toLocalHTLCs) has a lower CLTV value and is preimage
+		// available.
 		Htlcs: []channeldb.HTLC{htlc, htlcWithPreimage},
 	}
 	chanArb.notifyContractUpdate(newUpdate)
@@ -2610,8 +2621,8 @@ func TestChannelArbitratorAnchors(t *testing.T) {
 	newUpdate = &ContractUpdate{
 		HtlcKey: RemoteHtlcSet,
 		// This will make the deadline of the remote anchor resolution
-		// to be htlcWithPreimage's CLTV minus heightHint because the
-		// incoming HTLC (toRemoteHTLCs) has a lower CLTV.
+		// to be htlcWithPreimage's CLTV because the incoming HTLC
+		// (toRemoteHTLCs) has a lower CLTV.
 		Htlcs: []channeldb.HTLC{htlc, htlcWithPreimage},
 	}
 	chanArb.notifyContractUpdate(newUpdate)
@@ -2734,14 +2745,14 @@ func TestChannelArbitratorAnchors(t *testing.T) {
 
 	// We expect two anchor inputs, the local and the remote to be swept.
 	// Thus we should expect there are two deadlines used, both are equal
-	// to htlcWithPreimage's CLTV minus current block height.
+	// to htlcWithPreimage's CLTV.
 	require.Equal(t, 2, len(chanArbCtx.sweeper.deadlines))
 	require.EqualValues(t,
-		htlcWithPreimage.RefundTimeout-heightHint,
+		htlcWithPreimage.RefundTimeout,
 		chanArbCtx.sweeper.deadlines[0],
 	)
 	require.EqualValues(t,
-		htlcWithPreimage.RefundTimeout-heightHint,
+		htlcWithPreimage.RefundTimeout,
 		chanArbCtx.sweeper.deadlines[1],
 	)
 }

contractcourt/commit_sweep_resolver_test.go

@@ -143,6 +143,11 @@ func (s *mockSweeper) SweepInput(input input.Input, params sweep.Params) (
 		}
 	}
 
+	// Update the deadlines used if it's set.
+	params.DeadlineHeight.WhenSome(func(d int32) {
+		s.deadlines = append(s.deadlines, int(d))
+	})
+
 	result := make(chan sweep.Result, 1)
 	result <- sweep.Result{
 		Tx:  s.sweepTx,