lnwallet: thread thru input.AuxTapleaf to all relevant areas

In this commit, we start to thread thru the new aux tap leaf structures to all relevant areas. This includes: commitment outputs, resolution creation, breach handling, and also HTLC scripts.

Given the aux leaf store, and a struct that describes the current commitment, we can obtain the CommitAuxLeaves struct, then use that to derive the aux leaves for the commitment outputs and also HTLCs as well.

When restoring commitments and pay descs from disk, we'll store the aux leaves as custom TLV blobs on disk, then use the aux leaf store to map back to the concrete aux leaves when needed.

Author: Roasbeef

chainreg/chainregistry.go

@@ -24,6 +24,7 @@ import (
 	"github.com/lightningnetwork/lnd/chainntnfs/neutrinonotify"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/channeldb/models"
+	"github.com/lightningnetwork/lnd/fn"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/kvdb"
@@ -63,6 +64,10 @@ type Config struct {
 	// state.
 	ChanStateDB *channeldb.ChannelStateDB
 
+	// AuxLeafStore is an optional store that can be used to store auxiliary
+	// leaves for certain custom channel types.
+	AuxLeafStore fn.Option[lnwallet.AuxLeafStore]
+
 	// BlockCache is the main cache for storing block information.
 	BlockCache *blockcache.BlockCache
 

config_builder.go

@@ -34,6 +34,7 @@ import (
 	"github.com/lightningnetwork/lnd/chainreg"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/clock"
+	"github.com/lightningnetwork/lnd/fn"
 	"github.com/lightningnetwork/lnd/invoices"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/kvdb"
@@ -104,7 +105,7 @@ type DatabaseBuilder interface {
 type WalletConfigBuilder interface {
 	// BuildWalletConfig is responsible for creating or unlocking and then
 	// fully initializing a wallet.
-	BuildWalletConfig(context.Context, *DatabaseInstances,
+	BuildWalletConfig(context.Context, *DatabaseInstances, *AuxComponents,
 		*rpcperms.InterceptorChain,
 		[]*ListenerWithSignal) (*chainreg.PartialChainControl,
 		*btcwallet.Config, func(), error)
@@ -145,6 +146,17 @@ type ImplementationCfg struct {
 	// ChainControlBuilder is a type that can provide a custom wallet
 	// implementation.
 	ChainControlBuilder
+	// AuxComponents is a set of auxiliary components that can be used by
+	// lnd for certain custom channel types.
+	AuxComponents
+}
+
+// AuxComponents is a set of auxiliary components that can be used by lnd for
+// certain custom channel types.
+type AuxComponents struct {
+	// AuxLeafStore is an optional data source that can be used by custom
+	// channels to fetch+store various data.
+	AuxLeafStore fn.Option[lnwallet.AuxLeafStore]
 }
 
 // DefaultWalletImpl is the default implementation of our normal, btcwallet
@@ -229,7 +241,8 @@ func (d *DefaultWalletImpl) Permissions() map[string][]bakery.Op {
 //
 // NOTE: This is part of the WalletConfigBuilder interface.
 func (d *DefaultWalletImpl) BuildWalletConfig(ctx context.Context,
-	dbs *DatabaseInstances, interceptorChain *rpcperms.InterceptorChain,
+	dbs *DatabaseInstances, aux *AuxComponents,
+	interceptorChain *rpcperms.InterceptorChain,
 	grpcListeners []*ListenerWithSignal) (*chainreg.PartialChainControl,
 	*btcwallet.Config, func(), error) {
 
@@ -549,6 +562,7 @@ func (d *DefaultWalletImpl) BuildWalletConfig(ctx context.Context,
 		HeightHintDB:                dbs.HeightHintDB,
 		ChanStateDB:                 dbs.ChanStateDB.ChannelStateDB(),
 		NeutrinoCS:                  neutrinoCS,
+		AuxLeafStore:                aux.AuxLeafStore,
 		ActiveNetParams:             d.cfg.ActiveNetParams,
 		FeeURL:                      d.cfg.FeeURL,
 		Dialer: func(addr string) (net.Conn, error) {
@@ -607,8 +621,9 @@ func (d *DefaultWalletImpl) BuildWalletConfig(ctx context.Context,
 
 // proxyBlockEpoch proxies a block epoch subsections to the underlying neutrino
 // rebroadcaster client.
-func proxyBlockEpoch(notifier chainntnfs.ChainNotifier,
-) func() (*blockntfns.Subscription, error) {
+func proxyBlockEpoch(
+	notifier chainntnfs.ChainNotifier) func() (*blockntfns.Subscription,
+	error) {
 
 	return func() (*blockntfns.Subscription, error) {
 		blockEpoch, err := notifier.RegisterBlockEpochNtfn(
@@ -699,6 +714,7 @@ func (d *DefaultWalletImpl) BuildChainControl(
 		ChainIO:               walletController,
 		NetParams:             *walletConfig.NetParams,
 		CoinSelectionStrategy: walletConfig.CoinSelectionStrategy,
+		AuxLeafStore:          partialChainControl.Cfg.AuxLeafStore,
 	}
 
 	// The broadcast is already always active for neutrino nodes, so we
@@ -878,6 +894,10 @@ type DatabaseInstances struct {
 	// for native SQL queries for tables that already support it. This may
 	// be nil if the use-native-sql flag was not set.
 	NativeSQLStore *sqldb.BaseDB
+
+	// AuxLeafStore is an optional data source that can be used by custom
+	// channels to fetch+store various data.
+	AuxLeafStore fn.Option[lnwallet.AuxLeafStore]
 }
 
 // DefaultDatabaseBuilder is a type that builds the default database backends

contractcourt/breach_arbitrator_test.go

@@ -22,6 +22,7 @@ import (
 	"github.com/go-errors/errors"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/fn"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lntest/channels"
@@ -1590,6 +1591,7 @@ func testBreachSpends(t *testing.T, test breachTest) {
 	// Notify the breach arbiter about the breach.
 	retribution, err := lnwallet.NewBreachRetribution(
 		alice.State(), height, 1, forceCloseTx,
+		fn.None[lnwallet.AuxLeafStore](),
 	)
 	require.NoError(t, err, "unable to create breach retribution")
 
@@ -1799,6 +1801,7 @@ func TestBreachDelayedJusticeConfirmation(t *testing.T) {
 	// Notify the breach arbiter about the breach.
 	retribution, err := lnwallet.NewBreachRetribution(
 		alice.State(), height, uint32(blockHeight), forceCloseTx,
+		fn.None[lnwallet.AuxLeafStore](),
 	)
 	require.NoError(t, err, "unable to create breach retribution")
 

contractcourt/chain_arbitrator.go

@@ -217,6 +217,10 @@ type ChainArbitratorConfig struct {
 	// meanwhile, turn `PaymentCircuit` into an interface or bring it to a
 	// lower package.
 	QueryIncomingCircuit func(circuit models.CircuitKey) *models.CircuitKey
+
+	// AuxLeafStore is an optional store that can be used to store auxiliary
+	// leaves for certain custom channel types.
+	AuxLeafStore fn.Option[lnwallet.AuxLeafStore]
 }
 
 // ChainArbitrator is a sub-system that oversees the on-chain resolution of all
@@ -299,8 +303,13 @@ func (a *arbChannel) NewAnchorResolutions() (*lnwallet.AnchorResolutions,
 		return nil, err
 	}
 
+	var chanOpts []lnwallet.ChannelOpt
+	a.c.cfg.AuxLeafStore.WhenSome(func(s lnwallet.AuxLeafStore) {
+		chanOpts = append(chanOpts, lnwallet.WithLeafStore(s))
+	})
+
 	chanMachine, err := lnwallet.NewLightningChannel(
-		a.c.cfg.Signer, channel, nil,
+		a.c.cfg.Signer, channel, nil, chanOpts...,
 	)
 	if err != nil {
 		return nil, err
@@ -344,10 +353,15 @@ func (a *arbChannel) ForceCloseChan() (*lnwallet.LocalForceCloseSummary, error)
 		return nil, err
 	}
 
+	var chanOpts []lnwallet.ChannelOpt
+	a.c.cfg.AuxLeafStore.WhenSome(func(s lnwallet.AuxLeafStore) {
+		chanOpts = append(chanOpts, lnwallet.WithLeafStore(s))
+	})
+
 	// Finally, we'll force close the channel completing
 	// the force close workflow.
 	chanMachine, err := lnwallet.NewLightningChannel(
-		a.c.cfg.Signer, channel, nil,
+		a.c.cfg.Signer, channel, nil, chanOpts...,
 	)
 	if err != nil {
 		return nil, err

contractcourt/chain_watcher.go

@@ -188,6 +188,9 @@ type chainWatcherConfig struct {
 	// obfuscater. This is used by the chain watcher to identify which
 	// state was broadcast and confirmed on-chain.
 	extractStateNumHint func(*wire.MsgTx, [lnwallet.StateHintSize]byte) uint64
+
+	// auxLeafStore can be used to fetch information for custom channels.
+	auxLeafStore fn.Option[lnwallet.AuxLeafStore]
 }
 
 // chainWatcher is a system that's assigned to every active channel. The duty
@@ -421,15 +424,30 @@ func (c *chainWatcher) handleUnknownLocalState(
 		&c.cfg.chanState.LocalChanCfg, &c.cfg.chanState.RemoteChanCfg,
 	)
 
+	auxLeaves, err := lnwallet.AuxLeavesFromCommit(
+		c.cfg.chanState, c.cfg.chanState.LocalCommitment,
+		c.cfg.auxLeafStore, *commitKeyRing,
+	)
+	if err != nil {
+		return false, fmt.Errorf("unable to fetch aux leaves: %w", err)
+	}
+
 	// With the keys derived, we'll construct the remote script that'll be
 	// present if they have a non-dust balance on the commitment.
 	var leaseExpiry uint32
 	if c.cfg.chanState.ChanType.HasLeaseExpiration() {
 		leaseExpiry = c.cfg.chanState.ThawHeight
 	}
+
+	remoteAuxLeaf := fn.MapOption(
+		func(l lnwallet.CommitAuxLeaves) input.AuxTapLeaf {
+			return l.RemoteAuxLeaf
+		},
+	)(auxLeaves)
 	remoteScript, _, err := lnwallet.CommitScriptToRemote(
 		c.cfg.chanState.ChanType, c.cfg.chanState.IsInitiator,
-		commitKeyRing.ToRemoteKey, leaseExpiry, input.NoneTapLeaf(),
+		commitKeyRing.ToRemoteKey, leaseExpiry,
+		fn.FlattenOption(remoteAuxLeaf),
 	)
 	if err != nil {
 		return false, err
@@ -438,11 +456,16 @@ func (c *chainWatcher) handleUnknownLocalState(
 	// Next, we'll derive our script that includes the revocation base for
 	// the remote party allowing them to claim this output before the CSV
 	// delay if we breach.
+	localAuxLeaf := fn.MapOption(
+		func(l lnwallet.CommitAuxLeaves) input.AuxTapLeaf {
+			return l.LocalAuxLeaf
+		},
+	)(auxLeaves)
 	localScript, err := lnwallet.CommitScriptToSelf(
 		c.cfg.chanState.ChanType, c.cfg.chanState.IsInitiator,
 		commitKeyRing.ToLocalKey, commitKeyRing.RevocationKey,
 		uint32(c.cfg.chanState.LocalChanCfg.CsvDelay), leaseExpiry,
-		input.NoneTapLeaf(),
+		fn.FlattenOption(localAuxLeaf),
 	)
 	if err != nil {
 		return false, err
@@ -862,7 +885,7 @@ func (c *chainWatcher) handlePossibleBreach(commitSpend *chainntnfs.SpendDetail,
 	spendHeight := uint32(commitSpend.SpendingHeight)
 	retribution, err := lnwallet.NewBreachRetribution(
 		c.cfg.chanState, broadcastStateNum, spendHeight,
-		commitSpend.SpendingTx,
+		commitSpend.SpendingTx, c.cfg.auxLeafStore,
 	)
 
 	switch {
@@ -1073,8 +1096,8 @@ func (c *chainWatcher) dispatchLocalForceClose(
 		"detected", c.cfg.chanState.FundingOutpoint)
 
 	forceClose, err := lnwallet.NewLocalForceCloseSummary(
-		c.cfg.chanState, c.cfg.signer,
-		commitSpend.SpendingTx, stateNum,
+		c.cfg.chanState, c.cfg.signer, commitSpend.SpendingTx, stateNum,
+		c.cfg.auxLeafStore,
 	)
 	if err != nil {
 		return err
@@ -1167,7 +1190,7 @@ func (c *chainWatcher) dispatchRemoteForceClose(
 	// channel on-chain.
 	uniClose, err := lnwallet.NewUnilateralCloseSummary(
 		c.cfg.chanState, c.cfg.signer, commitSpend,
-		remoteCommit, commitPoint,
+		remoteCommit, commitPoint, c.cfg.auxLeafStore,
 	)
 	if err != nil {
 		return err

funding/manager.go

@@ -538,6 +538,10 @@ type Config struct {
 	// AliasManager is an implementation of the aliasHandler interface that
 	// abstracts away the handling of many alias functions.
 	AliasManager aliasHandler
+
+	// AuxLeafStore is an optional store that can be used to store auxiliary
+	// leaves for certain custom channel types.
+	AuxLeafStore fn.Option[lnwallet.AuxLeafStore]
 }
 
 // Manager acts as an orchestrator/bridge between the wallet's
@@ -1056,9 +1060,14 @@ func (f *Manager) advanceFundingState(channel *channeldb.OpenChannel,
 		}
 	}
 
+	var chanOpts []lnwallet.ChannelOpt
+	f.cfg.AuxLeafStore.WhenSome(func(s lnwallet.AuxLeafStore) {
+		chanOpts = append(chanOpts, lnwallet.WithLeafStore(s))
+	})
+
 	// We create the state-machine object which wraps the database state.
 	lnChannel, err := lnwallet.NewLightningChannel(
-		nil, channel, nil,
+		nil, channel, nil, chanOpts...,
 	)
 	if err != nil {
 		log.Errorf("Unable to create LightningChannel(%v): %v",

input/size_test.go

@@ -1386,7 +1386,7 @@ func genTimeoutTx(t *testing.T,
 	// Create the unsigned timeout tx.
 	timeoutTx, err := lnwallet.CreateHtlcTimeoutTx(
 		chanType, false, testOutPoint, testAmt, testCLTVExpiry,
-		testCSVDelay, 0, testPubkey, testPubkey,
+		testCSVDelay, 0, testPubkey, testPubkey, input.NoneTapLeaf(),
 	)
 	require.NoError(t, err)
 
@@ -1455,7 +1455,7 @@ func genSuccessTx(t *testing.T, chanType channeldb.ChannelType) *wire.MsgTx {
 	// Create the unsigned success tx.
 	successTx, err := lnwallet.CreateHtlcSuccessTx(
 		chanType, false, testOutPoint, testAmt, testCSVDelay, 0,
-		testPubkey, testPubkey,
+		testPubkey, testPubkey, input.NoneTapLeaf(),
 	)
 	require.NoError(t, err)
 

lnd.go

@@ -437,7 +437,8 @@ func Main(cfg *Config, lisCfg ListenerCfg, implCfg *ImplementationCfg,
 	defer cleanUp()
 
 	partialChainControl, walletConfig, cleanUp, err := implCfg.BuildWalletConfig(
-		ctx, dbs, interceptorChain, grpcListeners,
+		ctx, dbs, &implCfg.AuxComponents, interceptorChain,
+		grpcListeners,
 	)
 	if err != nil {
 		return mkErr("error creating wallet config: %v", err)
@@ -580,7 +581,7 @@ func Main(cfg *Config, lisCfg ListenerCfg, implCfg *ImplementationCfg,
 	server, err := newServer(
 		cfg, cfg.Listeners, dbs, activeChainControl, &idKeyDesc,
 		activeChainControl.Cfg.WalletUnlockParams.ChansToRestore,
-		multiAcceptor, torController, tlsManager,
+		multiAcceptor, torController, tlsManager, implCfg,
 	)
 	if err != nil {
 		return mkErr("unable to create server: %v", err)