Merge pull request #3821 from halseth/pluggable-anchors-lnwallet

[anchor] pluggable anchor commitments

Author: Roasbeef

breacharbiter.go

@@ -896,6 +896,13 @@ func (bo *breachedOutput) CraftInputScript(signer input.Signer, txn *wire.MsgTx,
 // must be built on top of the confirmation height before the output can be
 // spent.
 func (bo *breachedOutput) BlocksToMaturity() uint32 {
+	// If the output is a to_remote output we can claim, and it's of the
+	// confirmed type, we must wait one block before claiming it.
+	if bo.witnessType == input.CommitmentToRemoteConfirmed {
+		return 1
+	}
+
+	// All other breached outputs have no CSV delay.
 	return 0
 }
 
@@ -952,6 +959,12 @@ func newRetributionInfo(chanPoint *wire.OutPoint,
 			witnessType = input.CommitSpendNoDelayTweakless
 		}
 
+		// If the local delay is non-zero, it means this output is of
+		// the confirmed to_remote type.
+		if breachInfo.LocalDelay != 0 {
+			witnessType = input.CommitmentToRemoteConfirmed
+		}
+
 		localOutput := makeBreachedOutput(
 			&breachInfo.LocalOutpoint,
 			witnessType,
@@ -1117,6 +1130,7 @@ func (b *breachArbiter) sweepSpendableOutputsTxn(txWeight int64,
 	for _, input := range inputs {
 		txn.AddTxIn(&wire.TxIn{
 			PreviousOutPoint: *input.OutPoint(),
+			Sequence:         input.BlocksToMaturity(),
 		})
 	}
 

chanbackup/backup.go

@@ -62,6 +62,12 @@ func FetchBackupForChan(chanPoint wire.OutPoint,
 		return nil, fmt.Errorf("unable to find target channel")
 	}
 
+	// TODO(halseth): support chan backups for anchor types.
+	if targetChan.ChanType.HasAnchors() {
+		return nil, fmt.Errorf("channel type does not support " +
+			"backups yet")
+	}
+
 	// Once we have the target channel, we can assemble the backup using
 	// the source to obtain any extra information that we may need.
 	staticChanBackup, err := assembleChanBackup(chanSource, targetChan)
@@ -85,14 +91,19 @@ func FetchStaticChanBackups(chanSource LiveChannelSource) ([]Single, error) {
 	// Now that we have all the channels, we'll use the chanSource to
 	// obtain any auxiliary information we need to craft a backup for each
 	// channel.
-	staticChanBackups := make([]Single, len(openChans))
-	for i, openChan := range openChans {
+	staticChanBackups := make([]Single, 0, len(openChans))
+	for _, openChan := range openChans {
+		// TODO(halseth): support chan backups for anchor types.
+		if openChan.ChanType.HasAnchors() {
+			continue
+		}
+
 		chanBackup, err := assembleChanBackup(chanSource, openChan)
 		if err != nil {
 			return nil, err
 		}
 
-		staticChanBackups[i] = *chanBackup
+		staticChanBackups = append(staticChanBackups, *chanBackup)
 	}
 
 	return staticChanBackups, nil

chanbackup/pubsub.go

@@ -213,6 +213,12 @@ func (s *SubSwapper) backupUpdater() {
 			// For all new open channels, we'll create a new SCB
 			// given the required information.
 			for _, newChan := range chanUpdate.NewChans {
+				// TODO(halseth): support chan backups for
+				// anchor types.
+				if newChan.ChanType.HasAnchors() {
+					continue
+				}
+
 				log.Debugf("Adding channel %v to backup state",
 					newChan.FundingOutpoint)
 

channeldb/channel.go

@@ -176,6 +176,12 @@ const (
 	// disk. This bit may be on if the funding transaction was crafted by a
 	// wallet external to the primary daemon.
 	NoFundingTxBit ChannelType = 1 << 2
+
+	// AnchorOutputsBit indicates that the channel makes use of anchor
+	// outputs to bump the commitment transaction's effective feerate. This
+	// channel type also uses a delayed to_remote output script. If bit is
+	// set, we'll find the size of the anchor outputs in the database.
+	AnchorOutputsBit ChannelType = 1 << 3
 )
 
 // IsSingleFunder returns true if the channel type if one of the known single
@@ -201,6 +207,12 @@ func (c ChannelType) HasFundingTx() bool {
 	return c&NoFundingTxBit == 0
 }
 
+// HasAnchors returns true if this channel type has anchor ouputs on its
+// commitment.
+func (c ChannelType) HasAnchors() bool {
+	return c&AnchorOutputsBit == AnchorOutputsBit
+}
+
 // ChannelConstraints represents a set of constraints meant to allow a node to
 // limit their exposure, enact flow control and ensure that all HTLCs are
 // economically relevant. This struct will be mirrored for both sides of the
@@ -326,13 +338,15 @@ type ChannelCommitment struct {
 	// LocalBalance is the current available settled balance within the
 	// channel directly spendable by us.
 	//
-	// NOTE: This is the balance *after* subtracting any commitment fee.
+	// NOTE: This is the balance *after* subtracting any commitment fee,
+	// AND anchor output values.
 	LocalBalance lnwire.MilliSatoshi
 
 	// RemoteBalance is the current available settled balance within the
 	// channel directly spendable by the remote node.
 	//
-	// NOTE: This is the balance *after* subtracting any commitment fee.
+	// NOTE: This is the balance *after* subtracting any commitment fee,
+	// AND anchor output values.
 	RemoteBalance lnwire.MilliSatoshi
 
 	// CommitFee is the amount calculated to be paid in fees for the

config.go

@@ -345,7 +345,7 @@ type config struct {
 
 	Watchtower *lncfg.Watchtower `group:"watchtower" namespace:"watchtower"`
 
-	LegacyProtocol *lncfg.LegacyProtocol `group:"legacyprotocol" namespace:"legacyprotocol"`
+	ProtocolOptions *lncfg.ProtocolOptions `group:"protocol" namespace:"protocol"`
 
 	AllowCircularRoute bool `long:"allow-circular-route" description:"If true, our node will allow htlc forwards that arrive and depart on the same channel."`
 }

contractcourt/chain_watcher.go

@@ -351,9 +351,8 @@ func isOurCommitment(localChanCfg, remoteChanCfg channeldb.ChannelConfig,
 
 	// With the keys derived, we'll construct the remote script that'll be
 	// present if they have a non-dust balance on the commitment.
-	remoteDelay := uint32(remoteChanCfg.CsvDelay)
-	remoteScript, err := lnwallet.CommitScriptToRemote(
-		chanType, remoteDelay, commitKeyRing.ToRemoteKey,
+	remoteScript, _, err := lnwallet.CommitScriptToRemote(
+		chanType, commitKeyRing.ToRemoteKey,
 	)
 	if err != nil {
 		return false, err

contractcourt/commit_sweep_resolver.go

@@ -6,6 +6,7 @@ import (
 	"io"
 	"sync"
 
+	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcutil"
 	"github.com/lightningnetwork/lnd/input"
@@ -172,24 +173,45 @@ func (c *commitSweepResolver) Resolve() (ContractResolver, error) {
 		}
 	}
 
-	// We're dealing with our commitment transaction if the delay on the
-	// resolution isn't zero.
-	isLocalCommitTx := c.commitResolution.MaturityDelay != 0
-
-	// There're two types of commitments, those that have tweaks
-	// for the remote key (us in this case), and those that don't.
-	// We'll rely on the presence of the commitment tweak to to
-	// discern which type of commitment this is.
+	// The output is on our local commitment if the script starts with
+	// OP_IF for the revocation clause. On the remote commitment it will
+	// either be a regular P2WKH or a simple sig spend with a CSV delay.
+	isLocalCommitTx := c.commitResolution.SelfOutputSignDesc.WitnessScript[0] == txscript.OP_IF
+	isDelayedOutput := c.commitResolution.MaturityDelay != 0
+
+	c.log.Debugf("isDelayedOutput=%v, isLocalCommitTx=%v", isDelayedOutput,
+		isLocalCommitTx)
+
+	// There're three types of commitments, those that have tweaks
+	// for the remote key (us in this case), those that don't, and a third
+	// where there is no tweak and the output is delayed. On the local
+	// commitment our output will always be delayed. We'll rely on the
+	// presence of the commitment tweak to to discern which type of
+	// commitment this is.
 	var witnessType input.WitnessType
 	switch {
+
+	// Delayed output to us on our local commitment.
 	case isLocalCommitTx:
 		witnessType = input.CommitmentTimeLock
+
+	// A confirmed output to us on the remote commitment.
+	case isDelayedOutput:
+		witnessType = input.CommitmentToRemoteConfirmed
+
+	// A non-delayed output on the remote commitment where the key is
+	// tweakless.
 	case c.commitResolution.SelfOutputSignDesc.SingleTweak == nil:
 		witnessType = input.CommitSpendNoDelayTweakless
+
+	// A non-delayed output on the remote commitment where the key is
+	// tweaked.
 	default:
 		witnessType = input.CommitmentNoDelay
 	}
 
+	c.log.Infof("Sweeping with witness type: %v", witnessType)
+
 	// We'll craft an input with all the information required for
 	// the sweeper to create a fully valid sweeping transaction to
 	// recover these coins.

contractcourt/commit_sweep_resolver_test.go

@@ -133,6 +133,7 @@ func TestCommitSweepResolverNoDelay(t *testing.T) {
 			Output: &wire.TxOut{
 				Value: 100,
 			},
+			WitnessScript: []byte{0},
 		},
 	}
 
@@ -162,6 +163,7 @@ func TestCommitSweepResolverDelay(t *testing.T) {
 			Output: &wire.TxOut{
 				Value: amt,
 			},
+			WitnessScript: []byte{0},
 		},
 		MaturityDelay: 3,
 		SelfOutPoint:  outpoint,

contractcourt/htlc_success_resolver.go

@@ -118,6 +118,7 @@ func (h *htlcSuccessResolver) Resolve() (ContractResolver, error) {
 				&h.htlcResolution.SweepSignDesc,
 				h.htlcResolution.Preimage[:],
 				h.broadcastHeight,
+				h.htlcResolution.CsvDelay,
 			)
 
 			// With the input created, we can now generate the full

contractcourt/htlc_timeout_resolver_test.go

@@ -7,6 +7,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/input"
@@ -144,7 +145,8 @@ func TestHtlcTimeoutResolver(t *testing.T) {
 			timeout:      true,
 			txToBroadcast: func() (*wire.MsgTx, error) {
 				witness, err := input.SenderHtlcSpendTimeout(
-					nil, signer, fakeSignDesc, sweepTx,
+					nil, txscript.SigHashAll, signer,
+					fakeSignDesc, sweepTx,
 				)
 				if err != nil {
 					return nil, err
@@ -163,7 +165,8 @@ func TestHtlcTimeoutResolver(t *testing.T) {
 			timeout:      false,
 			txToBroadcast: func() (*wire.MsgTx, error) {
 				witness, err := input.ReceiverHtlcSpendRedeem(
-					nil, fakePreimageBytes, signer,
+					nil, txscript.SigHashAll,
+					fakePreimageBytes, signer,
 					fakeSignDesc, sweepTx,
 				)
 				if err != nil {

feature/default_sets.go

@@ -43,4 +43,8 @@ var defaultSetDesc = setDesc{
 		SetNodeAnn: {}, // N
 		SetInvoice: {}, // 9
 	},
+	lnwire.AnchorsOptional: {
+		SetInit:    {}, // I
+		SetNodeAnn: {}, // N
+	},
 }

feature/deps.go

@@ -55,6 +55,9 @@ var deps = depDesc{
 	lnwire.MPPOptional: {
 		lnwire.PaymentAddrOptional: {},
 	},
+	lnwire.AnchorsOptional: {
+		lnwire.StaticRemoteKeyOptional: {},
+	},
 }
 
 // ValidateDeps asserts that a feature vector sets all features and their

feature/manager.go

@@ -17,6 +17,9 @@ type Config struct {
 	// NoStaticRemoteKey unsets any optional or required StaticRemoteKey
 	// bits from all feature sets.
 	NoStaticRemoteKey bool
+
+	// NoAnchors unsets any bits signaling support for anchor outputs.
+	NoAnchors bool
 }
 
 // Manager is responsible for generating feature vectors for different requested
@@ -76,6 +79,10 @@ func newManager(cfg Config, desc setDesc) (*Manager, error) {
 			raw.Unset(lnwire.StaticRemoteKeyOptional)
 			raw.Unset(lnwire.StaticRemoteKeyRequired)
 		}
+		if cfg.NoAnchors {
+			raw.Unset(lnwire.AnchorsOptional)
+			raw.Unset(lnwire.AnchorsRequired)
+		}
 
 		// Ensure that all of our feature sets properly set any
 		// dependent features.