Merge pull request #9072 from lightningnetwork/extract-part3-from-sta…

…ging-branch

[custom channels 3/5]: Extract PART3 from mega staging branch

chainreg/chainregistry.go

@@ -68,6 +68,10 @@ type Config struct {
 	// leaves for certain custom channel types.
 	AuxLeafStore fn.Option[lnwallet.AuxLeafStore]
 
+	// AuxSigner is an optional signer that can be used to sign auxiliary
+	// leaves for certain custom channel types.
+	AuxSigner fn.Option[lnwallet.AuxSigner]
+
 	// BlockCache is the main cache for storing block information.
 	BlockCache *blockcache.BlockCache
 

channeldb/models/channel_edge_info.go

@@ -8,6 +8,7 @@ import (
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/wire"
+	"github.com/lightningnetwork/lnd/fn"
 )
 
 // ChannelEdgeInfo represents a fully authenticated channel along with all its
@@ -62,6 +63,11 @@ type ChannelEdgeInfo struct {
 	// the value output in the outpoint that created this channel.
 	Capacity btcutil.Amount
 
+	// TapscriptRoot is the optional Merkle root of the tapscript tree if
+	// this channel is a taproot channel that also commits to a tapscript
+	// tree (custom channel).
+	TapscriptRoot fn.Option[chainhash.Hash]
+
 	// ExtraOpaqueData is the set of data that was appended to this
 	// message, some of which we may not actually know how to iterate or
 	// parse. By holding onto this data, we ensure that we're able to

config_builder.go

@@ -34,6 +34,7 @@ import (
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/clock"
 	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/funding"
 	"github.com/lightningnetwork/lnd/invoices"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/kvdb"
@@ -167,6 +168,20 @@ type AuxComponents struct {
 	// MsgRouter is an optional message router that if set will be used in
 	// place of a new blank default message router.
 	MsgRouter fn.Option[msgmux.Router]
+
+	// AuxFundingController is an optional controller that can be used to
+	// modify the way we handle certain custom channel types. It's also
+	// able to automatically handle new custom protocol messages related to
+	// the funding process.
+	AuxFundingController fn.Option[funding.AuxFundingController]
+
+	// AuxSigner is an optional signer that can be used to sign auxiliary
+	// leaves for certain custom channel types.
+	AuxSigner fn.Option[lnwallet.AuxSigner]
+
+	// AuxDataParser is an optional data parser that can be used to parse
+	// auxiliary data for certain custom channel types.
+	AuxDataParser fn.Option[AuxDataParser]
 }
 
 // DefaultWalletImpl is the default implementation of our normal, btcwallet
@@ -573,6 +588,7 @@ func (d *DefaultWalletImpl) BuildWalletConfig(ctx context.Context,
 		ChanStateDB:                 dbs.ChanStateDB.ChannelStateDB(),
 		NeutrinoCS:                  neutrinoCS,
 		AuxLeafStore:                aux.AuxLeafStore,
+		AuxSigner:                   aux.AuxSigner,
 		ActiveNetParams:             d.cfg.ActiveNetParams,
 		FeeURL:                      d.cfg.FeeURL,
 		Fee: &lncfg.Fee{
@@ -730,6 +746,7 @@ func (d *DefaultWalletImpl) BuildChainControl(
 		NetParams:             *walletConfig.NetParams,
 		CoinSelectionStrategy: walletConfig.CoinSelectionStrategy,
 		AuxLeafStore:          partialChainControl.Cfg.AuxLeafStore,
+		AuxSigner:             partialChainControl.Cfg.AuxSigner,
 	}
 
 	// The broadcast is already always active for neutrino nodes, so we
@@ -912,10 +929,6 @@ 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

@@ -2360,9 +2360,12 @@ func createInitChannels(t *testing.T) (
 	)
 	bobSigner := input.NewMockSigner([]*btcec.PrivateKey{bobKeyPriv}, nil)
 
+	signerMock := lnwallet.NewDefaultAuxSignerMock(t)
 	alicePool := lnwallet.NewSigPool(1, aliceSigner)
 	channelAlice, err := lnwallet.NewLightningChannel(
 		aliceSigner, aliceChannelState, alicePool,
+		lnwallet.WithLeafStore(&lnwallet.MockAuxLeafStore{}),
+		lnwallet.WithAuxSigner(signerMock),
 	)
 	if err != nil {
 		return nil, nil, err
@@ -2375,6 +2378,8 @@ func createInitChannels(t *testing.T) (
 	bobPool := lnwallet.NewSigPool(1, bobSigner)
 	channelBob, err := lnwallet.NewLightningChannel(
 		bobSigner, bobChannelState, bobPool,
+		lnwallet.WithLeafStore(&lnwallet.MockAuxLeafStore{}),
+		lnwallet.WithAuxSigner(signerMock),
 	)
 	if err != nil {
 		return nil, nil, err

contractcourt/chain_arbitrator.go

@@ -221,6 +221,10 @@ type ChainArbitratorConfig struct {
 	// AuxLeafStore is an optional store that can be used to store auxiliary
 	// leaves for certain custom channel types.
 	AuxLeafStore fn.Option[lnwallet.AuxLeafStore]
+
+	// AuxSigner is an optional signer that can be used to sign auxiliary
+	// leaves for certain custom channel types.
+	AuxSigner fn.Option[lnwallet.AuxSigner]
 }
 
 // ChainArbitrator is a sub-system that oversees the on-chain resolution of all
@@ -307,6 +311,9 @@ func (a *arbChannel) NewAnchorResolutions() (*lnwallet.AnchorResolutions,
 	a.c.cfg.AuxLeafStore.WhenSome(func(s lnwallet.AuxLeafStore) {
 		chanOpts = append(chanOpts, lnwallet.WithLeafStore(s))
 	})
+	a.c.cfg.AuxSigner.WhenSome(func(s lnwallet.AuxSigner) {
+		chanOpts = append(chanOpts, lnwallet.WithAuxSigner(s))
+	})
 
 	chanMachine, err := lnwallet.NewLightningChannel(
 		a.c.cfg.Signer, channel, nil, chanOpts...,
@@ -357,6 +364,9 @@ func (a *arbChannel) ForceCloseChan() (*lnwallet.LocalForceCloseSummary, error)
 	a.c.cfg.AuxLeafStore.WhenSome(func(s lnwallet.AuxLeafStore) {
 		chanOpts = append(chanOpts, lnwallet.WithLeafStore(s))
 	})
+	a.c.cfg.AuxSigner.WhenSome(func(s lnwallet.AuxSigner) {
+		chanOpts = append(chanOpts, lnwallet.WithAuxSigner(s))
+	})
 
 	// Finally, we'll force close the channel completing
 	// the force close workflow.

discovery/gossiper.go

@@ -20,6 +20,7 @@ import (
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/channeldb/models"
+	"github.com/lightningnetwork/lnd/fn"
 	"github.com/lightningnetwork/lnd/graph"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/kvdb"
@@ -82,9 +83,10 @@ var (
 // can provide that serve useful when processing a specific network
 // announcement.
 type optionalMsgFields struct {
-	capacity     *btcutil.Amount
-	channelPoint *wire.OutPoint
-	remoteAlias  *lnwire.ShortChannelID
+	capacity      *btcutil.Amount
+	channelPoint  *wire.OutPoint
+	remoteAlias   *lnwire.ShortChannelID
+	tapscriptRoot fn.Option[chainhash.Hash]
 }
 
 // apply applies the optional fields within the functional options.
@@ -115,6 +117,14 @@ func ChannelPoint(op wire.OutPoint) OptionalMsgField {
 	}
 }
 
+// TapscriptRoot is an optional field that lets the gossiper know of the root of
+// the tapscript tree for a custom channel.
+func TapscriptRoot(root fn.Option[chainhash.Hash]) OptionalMsgField {
+	return func(f *optionalMsgFields) {
+		f.tapscriptRoot = root
+	}
+}
+
 // RemoteAlias is an optional field that lets the gossiper know that a locally
 // sent channel update is actually an update for the peer that should replace
 // the ShortChannelID field with the remote's alias. This is only used for
@@ -2598,6 +2608,9 @@ func (d *AuthenticatedGossiper) handleChanAnnouncement(nMsg *networkMsg,
 			cp := *nMsg.optionalMsgFields.channelPoint
 			edge.ChannelPoint = cp
 		}
+
+		// Optional tapscript root for custom channels.
+		edge.TapscriptRoot = nMsg.optionalMsgFields.tapscriptRoot
 	}
 
 	log.Debugf("Adding edge for short_chan_id: %v", scid.ToUint64())

funding/aux_funding.go

@@ -0,0 +1,51 @@
+package funding
+
+import (
+	"github.com/btcsuite/btcd/chaincfg/chainhash"
+	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/lntypes"
+	"github.com/lightningnetwork/lnd/lnwallet"
+	"github.com/lightningnetwork/lnd/msgmux"
+)
+
+// AuxFundingDescResult is a type alias for a function that returns an optional
+// aux funding desc.
+type AuxFundingDescResult = fn.Result[fn.Option[lnwallet.AuxFundingDesc]]
+
+// AuxTapscriptResult is a type alias for a function that returns an optional
+// tapscript root.
+type AuxTapscriptResult = fn.Result[fn.Option[chainhash.Hash]]
+
+// AuxFundingController permits the implementation of the funding of custom
+// channels types. The controller serves as a MsgEndpoint which allows it to
+// intercept custom messages, or even the regular funding messages. The
+// controller might also pass along an aux funding desc based on an existing
+// pending channel ID.
+type AuxFundingController interface {
+	// Endpoint is the embedded interface that signals that the funding
+	// controller is also a message endpoint. This'll allow it to handle
+	// custom messages specific to the funding type.
+	msgmux.Endpoint
+
+	// DescFromPendingChanID takes a pending channel ID, that may already be
+	// known due to prior custom channel messages, and maybe returns an aux
+	// funding desc which can be used to modify how a channel is funded.
+	DescFromPendingChanID(pid PendingChanID, openChan lnwallet.AuxChanState,
+		keyRing lntypes.Dual[lnwallet.CommitmentKeyRing],
+		initiator bool) AuxFundingDescResult
+
+	// DeriveTapscriptRoot takes a pending channel ID and maybe returns a
+	// tapscript root that should be used when creating any MuSig2 sessions
+	// for a channel.
+	DeriveTapscriptRoot(PendingChanID) AuxTapscriptResult
+
+	// ChannelReady is called when a channel has been fully opened (multiple
+	// confirmations) and is ready to be used. This can be used to perform
+	// any final setup or cleanup.
+	ChannelReady(openChan lnwallet.AuxChanState) error
+
+	// ChannelFinalized is called when a channel has been fully finalized.
+	// In this state, we've received the commitment sig from the remote
+	// party, so we are safe to broadcast the funding transaction.
+	ChannelFinalized(PendingChanID) error
+}