12583319996

Committed 02 Jan 2025 01:38PM UTC coverage: 57.522% (-1.1%) from 58.598%

Build # 12583319996

Build Type

Pull #9361

github

Committed by

starius

Commit Message

fn/ContextGuard: use context.AfterFunc to wait

Simplifies context cancellation handling by using context.AfterFunc instead of a
goroutine to wait for context cancellation. This approach avoids the overhead of
a goroutine during the waiting period.

For ctxQuitUnsafe, since g.quit is closed only in the Quit method (which also
cancels all associated contexts), waiting on context cancellation ensures the
same behavior without unnecessary dependency on g.quit.

Added a test to ensure that the Create method does not launch any goroutines.

Pull Request Pull Request #9361: fn: optimize context guard

Run Details

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Source File
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0.0

/config_builder.go

package lnd

import (
        "bytes"
        "context"
        "database/sql"
        "errors"
        "fmt"
        "net"
        "os"
        "path/filepath"
        "sort"
        "strconv"
        "strings"
        "sync/atomic"
        "time"

        "github.com/btcsuite/btcd/chaincfg"
        "github.com/btcsuite/btcd/chaincfg/chainhash"
        "github.com/btcsuite/btcd/wire"
        "github.com/btcsuite/btclog/v2"
        "github.com/btcsuite/btcwallet/chain"
        "github.com/btcsuite/btcwallet/waddrmgr"
        "github.com/btcsuite/btcwallet/wallet"
        "github.com/btcsuite/btcwallet/walletdb"
        proxy "github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
        "github.com/lightninglabs/neutrino"
        "github.com/lightninglabs/neutrino/blockntfns"
        "github.com/lightninglabs/neutrino/headerfs"
        "github.com/lightninglabs/neutrino/pushtx"
        "github.com/lightningnetwork/lnd/blockcache"
        "github.com/lightningnetwork/lnd/chainntnfs"
        "github.com/lightningnetwork/lnd/chainreg"
        "github.com/lightningnetwork/lnd/channeldb"
        "github.com/lightningnetwork/lnd/clock"
        "github.com/lightningnetwork/lnd/fn/v2"
        "github.com/lightningnetwork/lnd/funding"
        graphdb "github.com/lightningnetwork/lnd/graph/db"
        "github.com/lightningnetwork/lnd/htlcswitch"
        "github.com/lightningnetwork/lnd/invoices"
        "github.com/lightningnetwork/lnd/keychain"
        "github.com/lightningnetwork/lnd/kvdb"
        "github.com/lightningnetwork/lnd/lncfg"
        "github.com/lightningnetwork/lnd/lnrpc"
        "github.com/lightningnetwork/lnd/lnwallet"
        "github.com/lightningnetwork/lnd/lnwallet/btcwallet"
        "github.com/lightningnetwork/lnd/lnwallet/chancloser"
        "github.com/lightningnetwork/lnd/lnwallet/rpcwallet"
        "github.com/lightningnetwork/lnd/macaroons"
        "github.com/lightningnetwork/lnd/msgmux"
        "github.com/lightningnetwork/lnd/rpcperms"
        "github.com/lightningnetwork/lnd/signal"
        "github.com/lightningnetwork/lnd/sqldb"
        "github.com/lightningnetwork/lnd/sweep"
        "github.com/lightningnetwork/lnd/walletunlocker"
        "github.com/lightningnetwork/lnd/watchtower"
        "github.com/lightningnetwork/lnd/watchtower/wtclient"
        "github.com/lightningnetwork/lnd/watchtower/wtdb"
        "google.golang.org/grpc"
        "gopkg.in/macaroon-bakery.v2/bakery"
)

// GrpcRegistrar is an interface that must be satisfied by an external subserver
// that wants to be able to register its own gRPC server onto lnd's main
// grpc.Server instance.
type GrpcRegistrar interface {
        // RegisterGrpcSubserver is called for each net.Listener on which lnd
        // creates a grpc.Server instance. External subservers implementing this
        // method can then register their own gRPC server structs to the main
        // server instance.
        RegisterGrpcSubserver(*grpc.Server) error
}

// RestRegistrar is an interface that must be satisfied by an external subserver
// that wants to be able to register its own REST mux onto lnd's main
// proxy.ServeMux instance.
type RestRegistrar interface {
        // RegisterRestSubserver is called after lnd creates the main
        // proxy.ServeMux instance. External subservers implementing this method
        // can then register their own REST proxy stubs to the main server
        // instance.
        RegisterRestSubserver(context.Context, *proxy.ServeMux, string,
                []grpc.DialOption) error
}

// ExternalValidator is an interface that must be satisfied by an external
// macaroon validator.
type ExternalValidator interface {
        macaroons.MacaroonValidator

        // Permissions returns the permissions that the external validator is
        // validating. It is a map between the full HTTP URI of each RPC and its
        // required macaroon permissions. If multiple action/entity tuples are
        // specified per URI, they are all required. See rpcserver.go for a list
        // of valid action and entity values.
        Permissions() map[string][]bakery.Op
}

// DatabaseBuilder is an interface that must be satisfied by the implementation
// that provides lnd's main database backend instances.
type DatabaseBuilder interface {
        // BuildDatabase extracts the current databases that we'll use for
        // normal operation in the daemon. A function closure that closes all
        // opened databases is also returned.
        BuildDatabase(ctx context.Context) (*DatabaseInstances, func(), error)
}

// WalletConfigBuilder is an interface that must be satisfied by a custom wallet
// implementation.
type WalletConfigBuilder interface {
        // BuildWalletConfig is responsible for creating or unlocking and then
        // fully initializing a wallet.
        BuildWalletConfig(context.Context, *DatabaseInstances, *AuxComponents,
                *rpcperms.InterceptorChain,
                []*ListenerWithSignal) (*chainreg.PartialChainControl,
                *btcwallet.Config, func(), error)
}

// ChainControlBuilder is an interface that must be satisfied by a custom wallet
// implementation.
type ChainControlBuilder interface {
        // BuildChainControl is responsible for creating a fully populated chain
        // control instance from a wallet.
        BuildChainControl(*chainreg.PartialChainControl,
                *btcwallet.Config) (*chainreg.ChainControl, func(), error)
}

// ImplementationCfg is a struct that holds all configuration items for
// components that can be implemented outside lnd itself.
type ImplementationCfg struct {
        // GrpcRegistrar is a type that can register additional gRPC subservers
        // before the main gRPC server is started.
        GrpcRegistrar

        // RestRegistrar is a type that can register additional REST subservers
        // before the main REST proxy is started.
        RestRegistrar

        // ExternalValidator is a type that can provide external macaroon
        // validation.
        ExternalValidator

        // DatabaseBuilder is a type that can provide lnd's main database
        // backend instances.
        DatabaseBuilder

        // WalletConfigBuilder is a type that can provide a wallet configuration
        // with a fully loaded and unlocked wallet.
        WalletConfigBuilder

        // 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]

        // TrafficShaper is an optional traffic shaper that can be used to
        // control the outgoing channel of a payment.
        TrafficShaper fn.Option[htlcswitch.AuxTrafficShaper]

        // 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]

        // AuxChanCloser is an optional channel closer that can be used to
        // modify the way a coop-close transaction is constructed.
        AuxChanCloser fn.Option[chancloser.AuxChanCloser]

        // AuxSweeper is an optional interface that can be used to modify the
        // way sweep transaction are generated.
        AuxSweeper fn.Option[sweep.AuxSweeper]

        // AuxContractResolver is an optional interface that can be used to
        // modify the way contracts are resolved.
        AuxContractResolver fn.Option[lnwallet.AuxContractResolver]
}

// DefaultWalletImpl is the default implementation of our normal, btcwallet
// backed configuration.
type DefaultWalletImpl struct {
        cfg         *Config
        logger      btclog.Logger
        interceptor signal.Interceptor

        watchOnly        bool
        migrateWatchOnly bool
        pwService        *walletunlocker.UnlockerService
}

// NewDefaultWalletImpl creates a new default wallet implementation.
func NewDefaultWalletImpl(cfg *Config, logger btclog.Logger,
        interceptor signal.Interceptor, watchOnly bool) *DefaultWalletImpl {

        return &DefaultWalletImpl{
                cfg:         cfg,
                logger:      logger,
                interceptor: interceptor,
                watchOnly:   watchOnly,
                pwService:   createWalletUnlockerService(cfg),
        }
}

// RegisterRestSubserver is called after lnd creates the main proxy.ServeMux
// instance. External subservers implementing this method can then register
// their own REST proxy stubs to the main server instance.
//
// NOTE: This is part of the GrpcRegistrar interface.
func (d *DefaultWalletImpl) RegisterRestSubserver(ctx context.Context,
        mux *proxy.ServeMux, restProxyDest string,
        restDialOpts []grpc.DialOption) error {

        return lnrpc.RegisterWalletUnlockerHandlerFromEndpoint(
                ctx, mux, restProxyDest, restDialOpts,
        )
}

// RegisterGrpcSubserver is called for each net.Listener on which lnd creates a
// grpc.Server instance. External subservers implementing this method can then
// register their own gRPC server structs to the main server instance.
//
// NOTE: This is part of the GrpcRegistrar interface.
func (d *DefaultWalletImpl) RegisterGrpcSubserver(s *grpc.Server) error {
        lnrpc.RegisterWalletUnlockerServer(s, d.pwService)

        return nil
}

// ValidateMacaroon extracts the macaroon from the context's gRPC metadata,
// checks its signature, makes sure all specified permissions for the called
// method are contained within and finally ensures all caveat conditions are
// met. A non-nil error is returned if any of the checks fail.
//
// NOTE: This is part of the ExternalValidator interface.
func (d *DefaultWalletImpl) ValidateMacaroon(ctx context.Context,
        requiredPermissions []bakery.Op, fullMethod string) error {

        // Because the default implementation does not return any permissions,
        // we shouldn't be registered as an external validator at all and this
        // should never be invoked.
        return fmt.Errorf("default implementation does not support external " +
                "macaroon validation")
}

// Permissions returns the permissions that the external validator is
// validating. It is a map between the full HTTP URI of each RPC and its
// required macaroon permissions. If multiple action/entity tuples are specified
// per URI, they are all required. See rpcserver.go for a list of valid action
// and entity values.
//
// NOTE: This is part of the ExternalValidator interface.
func (d *DefaultWalletImpl) Permissions() map[string][]bakery.Op {
        return nil
}

// BuildWalletConfig is responsible for creating or unlocking and then
// fully initializing a wallet.
//
// NOTE: This is part of the WalletConfigBuilder interface.
func (d *DefaultWalletImpl) BuildWalletConfig(ctx context.Context,
        dbs *DatabaseInstances, aux *AuxComponents,
        interceptorChain *rpcperms.InterceptorChain,
        grpcListeners []*ListenerWithSignal) (*chainreg.PartialChainControl,
        *btcwallet.Config, func(), error) {

        // Keep track of our various cleanup functions. We use a defer function
        // as well to not repeat ourselves with every return statement.
        var (
                cleanUpTasks []func()
                earlyExit    = true
                cleanUp      = func() {
                        for _, fn := range cleanUpTasks {
                                if fn == nil {
                                        continue
                                }

                                fn()
                        }
                }
        )
        defer func() {
                if earlyExit {
                        cleanUp()
                }
        }()

        // Initialize a new block cache.
        blockCache := blockcache.NewBlockCache(d.cfg.BlockCacheSize)

        // Before starting the wallet, we'll create and start our Neutrino
        // light client instance, if enabled, in order to allow it to sync
        // while the rest of the daemon continues startup.
        mainChain := d.cfg.Bitcoin
        var neutrinoCS *neutrino.ChainService
        if mainChain.Node == "neutrino" {
                neutrinoBackend, neutrinoCleanUp, err := initNeutrinoBackend(
                        ctx, d.cfg, mainChain.ChainDir, blockCache,
                )
                if err != nil {
                        err := fmt.Errorf("unable to initialize neutrino "+
                                "backend: %v", err)
                        d.logger.Error(err)
                        return nil, nil, nil, err
                }
                cleanUpTasks = append(cleanUpTasks, neutrinoCleanUp)
                neutrinoCS = neutrinoBackend
        }

        var (
                walletInitParams = walletunlocker.WalletUnlockParams{
                        // In case we do auto-unlock, we need to be able to send
                        // into the channel without blocking so we buffer it.
                        MacResponseChan: make(chan []byte, 1),
                }
                privateWalletPw = lnwallet.DefaultPrivatePassphrase
                publicWalletPw  = lnwallet.DefaultPublicPassphrase
        )

        // If the user didn't request a seed, then we'll manually assume a
        // wallet birthday of now, as otherwise the seed would've specified
        // this information.
        walletInitParams.Birthday = time.Now()

        d.pwService.SetLoaderOpts([]btcwallet.LoaderOption{dbs.WalletDB})
        d.pwService.SetMacaroonDB(dbs.MacaroonDB)
        walletExists, err := d.pwService.WalletExists()
        if err != nil {
                return nil, nil, nil, err
        }

        if !walletExists {
                interceptorChain.SetWalletNotCreated()
        } else {
                interceptorChain.SetWalletLocked()
        }

        // If we've started in auto unlock mode, then a wallet should already
        // exist because we don't want to enable the RPC unlocker in that case
        // for security reasons (an attacker could inject their seed since the
        // RPC is unauthenticated). Only if the user explicitly wants to allow
        // wallet creation we don't error out here.
        if d.cfg.WalletUnlockPasswordFile != "" && !walletExists &&
                !d.cfg.WalletUnlockAllowCreate {

                return nil, nil, nil, fmt.Errorf("wallet unlock password file " +
                        "was specified but wallet does not exist; initialize " +
                        "the wallet before using auto unlocking")
        }

        // What wallet mode are we running in? We've already made sure the no
        // seed backup and auto unlock aren't both set during config parsing.
        switch {
        // No seed backup means we're also using the default password.
        case d.cfg.NoSeedBackup:
                // We continue normally, the default password has already been
                // set above.

        // A password for unlocking is provided in a file.
        case d.cfg.WalletUnlockPasswordFile != "" && walletExists:
                d.logger.Infof("Attempting automatic wallet unlock with " +
                        "password provided in file")
                pwBytes, err := os.ReadFile(d.cfg.WalletUnlockPasswordFile)
                if err != nil {
                        return nil, nil, nil, fmt.Errorf("error reading "+
                                "password from file %s: %v",
                                d.cfg.WalletUnlockPasswordFile, err)
                }

                // Remove any newlines at the end of the file. The lndinit tool
                // won't ever write a newline but maybe the file was provisioned
                // by another process or user.
                pwBytes = bytes.TrimRight(pwBytes, "\r\n")

                // We have the password now, we can ask the unlocker service to
                // do the unlock for us.
                unlockedWallet, unloadWalletFn, err := d.pwService.LoadAndUnlock(
                        pwBytes, 0,
                )
                if err != nil {
                        return nil, nil, nil, fmt.Errorf("error unlocking "+
                                "wallet with password from file: %v", err)
                }

                cleanUpTasks = append(cleanUpTasks, func() {
                        if err := unloadWalletFn(); err != nil {
                                d.logger.Errorf("Could not unload wallet: %v",
                                        err)
                        }
                })

                privateWalletPw = pwBytes
                publicWalletPw = pwBytes
                walletInitParams.Wallet = unlockedWallet
                walletInitParams.UnloadWallet = unloadWalletFn

        // If none of the automatic startup options are selected, we fall back
        // to the default behavior of waiting for the wallet creation/unlocking
        // over RPC.
        default:
                if err := d.interceptor.Notifier.NotifyReady(false); err != nil {
                        return nil, nil, nil, err
                }

                params, err := waitForWalletPassword(
                        d.cfg, d.pwService, []btcwallet.LoaderOption{dbs.WalletDB},
                        d.interceptor.ShutdownChannel(),
                )
                if err != nil {
                        err := fmt.Errorf("unable to set up wallet password "+
                                "listeners: %v", err)
                        d.logger.Error(err)
                        return nil, nil, nil, err
                }

                walletInitParams = *params
                privateWalletPw = walletInitParams.Password
                publicWalletPw = walletInitParams.Password
                cleanUpTasks = append(cleanUpTasks, func() {
                        if err := walletInitParams.UnloadWallet(); err != nil {
                                d.logger.Errorf("Could not unload wallet: %v",
                                        err)
                        }
                })

                if walletInitParams.RecoveryWindow > 0 {
                        d.logger.Infof("Wallet recovery mode enabled with "+
                                "address lookahead of %d addresses",
                                walletInitParams.RecoveryWindow)
                }
        }

        var macaroonService *macaroons.Service
        if !d.cfg.NoMacaroons {
                // Create the macaroon authentication/authorization service.
                rootKeyStore, err := macaroons.NewRootKeyStorage(dbs.MacaroonDB)
                if err != nil {
                        return nil, nil, nil, err
                }
                macaroonService, err = macaroons.NewService(
                        rootKeyStore, "lnd", walletInitParams.StatelessInit,
                        macaroons.IPLockChecker,
                        macaroons.CustomChecker(interceptorChain),
                )
                if err != nil {
                        err := fmt.Errorf("unable to set up macaroon "+
                                "authentication: %v", err)
                        d.logger.Error(err)
                        return nil, nil, nil, err
                }
                cleanUpTasks = append(cleanUpTasks, func() {
                        if err := macaroonService.Close(); err != nil {
                                d.logger.Errorf("Could not close macaroon "+
                                        "service: %v", err)
                        }
                })

                // Try to unlock the macaroon store with the private password.
                // Ignore ErrAlreadyUnlocked since it could be unlocked by the
                // wallet unlocker.
                err = macaroonService.CreateUnlock(&privateWalletPw)
                if err != nil && err != macaroons.ErrAlreadyUnlocked {
                        err := fmt.Errorf("unable to unlock macaroons: %w", err)
                        d.logger.Error(err)
                        return nil, nil, nil, err
                }

                // If we have a macaroon root key from the init wallet params,
                // set the root key before baking any macaroons.
                if len(walletInitParams.MacRootKey) > 0 {
                        err := macaroonService.SetRootKey(
                                walletInitParams.MacRootKey,
                        )
                        if err != nil {
                                return nil, nil, nil, err
                        }
                }

                // Send an admin macaroon to all our listeners that requested
                // one by setting a non-nil macaroon channel.
                adminMacBytes, err := bakeMacaroon(
                        ctx, macaroonService, adminPermissions(),
                )
                if err != nil {
                        return nil, nil, nil, err
                }
                for _, lis := range grpcListeners {
                        if lis.MacChan != nil {
                                lis.MacChan <- adminMacBytes
                        }
                }

                // In case we actually needed to unlock the wallet, we now need
                // to create an instance of the admin macaroon and send it to
                // the unlocker so it can forward it to the user. In no seed
                // backup mode, there's nobody listening on the channel and we'd
                // block here forever.
                if !d.cfg.NoSeedBackup {
                        // The channel is buffered by one element so writing
                        // should not block here.
                        walletInitParams.MacResponseChan <- adminMacBytes
                }

                // If the user requested a stateless initialization, no macaroon
                // files should be created.
                if !walletInitParams.StatelessInit {
                        // Create default macaroon files for lncli to use if
                        // they don't exist.
                        err = genDefaultMacaroons(
                                ctx, macaroonService, d.cfg.AdminMacPath,
                                d.cfg.ReadMacPath, d.cfg.InvoiceMacPath,
                        )
                        if err != nil {
                                err := fmt.Errorf("unable to create macaroons "+
                                        "%v", err)
                                d.logger.Error(err)
                                return nil, nil, nil, err
                        }
                }

                // As a security service to the user, if they requested
                // stateless initialization and there are macaroon files on disk
                // we log a warning.
                if walletInitParams.StatelessInit {
                        msg := "Found %s macaroon on disk (%s) even though " +
                                "--stateless_init was requested. Unencrypted " +
                                "state is accessible by the host system. You " +
                                "should change the password and use " +
                                "--new_mac_root_key with --stateless_init to " +
                                "clean up and invalidate old macaroons."

                        if lnrpc.FileExists(d.cfg.AdminMacPath) {
                                d.logger.Warnf(msg, "admin", d.cfg.AdminMacPath)
                        }
                        if lnrpc.FileExists(d.cfg.ReadMacPath) {
                                d.logger.Warnf(msg, "readonly", d.cfg.ReadMacPath)
                        }
                        if lnrpc.FileExists(d.cfg.InvoiceMacPath) {
                                d.logger.Warnf(msg, "invoice", d.cfg.InvoiceMacPath)
                        }
                }

                // We add the macaroon service to our RPC interceptor. This
                // will start checking macaroons against permissions on every
                // RPC invocation.
                interceptorChain.AddMacaroonService(macaroonService)
        }

        // Now that the wallet password has been provided, transition the RPC
        // state into Unlocked.
        interceptorChain.SetWalletUnlocked()

        // Since calls to the WalletUnlocker service wait for a response on the
        // macaroon channel, we close it here to make sure they return in case
        // we did not return the admin macaroon above. This will be the case if
        // --no-macaroons is used.
        close(walletInitParams.MacResponseChan)

        // We'll also close all the macaroon channels since lnd is done sending
        // macaroon data over it.
        for _, lis := range grpcListeners {
                if lis.MacChan != nil {
                        close(lis.MacChan)
                }
        }

        // With the information parsed from the configuration, create valid
        // instances of the pertinent interfaces required to operate the
        // Lightning Network Daemon.
        //
        // When we create the chain control, we need storage for the height
        // hints and also the wallet itself, for these two we want them to be
        // replicated, so we'll pass in the remote channel DB instance.
        chainControlCfg := &chainreg.Config{
                Bitcoin:                     d.cfg.Bitcoin,
                HeightHintCacheQueryDisable: d.cfg.HeightHintCacheQueryDisable,
                NeutrinoMode:                d.cfg.NeutrinoMode,
                BitcoindMode:                d.cfg.BitcoindMode,
                BtcdMode:                    d.cfg.BtcdMode,
                HeightHintDB:                dbs.HeightHintDB,
                ChanStateDB:                 dbs.ChanStateDB.ChannelStateDB(),
                NeutrinoCS:                  neutrinoCS,
                AuxLeafStore:                aux.AuxLeafStore,
                AuxSigner:                   aux.AuxSigner,
                ActiveNetParams:             d.cfg.ActiveNetParams,
                FeeURL:                      d.cfg.FeeURL,
                Fee: &lncfg.Fee{
                        URL:              d.cfg.Fee.URL,
                        MinUpdateTimeout: d.cfg.Fee.MinUpdateTimeout,
                        MaxUpdateTimeout: d.cfg.Fee.MaxUpdateTimeout,
                },
                Dialer: func(addr string) (net.Conn, error) {
                        return d.cfg.net.Dial(
                                "tcp", addr, d.cfg.ConnectionTimeout,
                        )
                },
                BlockCache:         blockCache,
                WalletUnlockParams: &walletInitParams,
        }

        // Let's go ahead and create the partial chain control now that is only
        // dependent on our configuration and doesn't require any wallet
        // specific information.
        partialChainControl, pccCleanup, err := chainreg.NewPartialChainControl(
                chainControlCfg,
        )
        cleanUpTasks = append(cleanUpTasks, pccCleanup)
        if err != nil {
                err := fmt.Errorf("unable to create partial chain control: %w",
                        err)
                d.logger.Error(err)
                return nil, nil, nil, err
        }

        walletConfig := &btcwallet.Config{
                PrivatePass:      privateWalletPw,
                PublicPass:       publicWalletPw,
                Birthday:         walletInitParams.Birthday,
                RecoveryWindow:   walletInitParams.RecoveryWindow,
                NetParams:        d.cfg.ActiveNetParams.Params,
                CoinType:         d.cfg.ActiveNetParams.CoinType,
                Wallet:           walletInitParams.Wallet,
                LoaderOptions:    []btcwallet.LoaderOption{dbs.WalletDB},
                ChainSource:      partialChainControl.ChainSource,
                WatchOnly:        d.watchOnly,
                MigrateWatchOnly: d.migrateWatchOnly,
        }

        // Parse coin selection strategy.
        switch d.cfg.CoinSelectionStrategy {
        case "largest":
                walletConfig.CoinSelectionStrategy = wallet.CoinSelectionLargest

        case "random":
                walletConfig.CoinSelectionStrategy = wallet.CoinSelectionRandom

        default:
                return nil, nil, nil, fmt.Errorf("unknown coin selection "+
                        "strategy %v", d.cfg.CoinSelectionStrategy)
        }

        earlyExit = false
        return partialChainControl, walletConfig, cleanUp, nil
}

// proxyBlockEpoch proxies a block epoch subsections to the underlying neutrino
// rebroadcaster client.
func proxyBlockEpoch(
        notifier chainntnfs.ChainNotifier) func() (*blockntfns.Subscription,
        error) {

        return func() (*blockntfns.Subscription, error) {
                blockEpoch, err := notifier.RegisterBlockEpochNtfn(
                        nil,
                )
                if err != nil {
                        return nil, err
                }

                sub := blockntfns.Subscription{
                        Notifications: make(chan blockntfns.BlockNtfn, 6),
                        Cancel:        blockEpoch.Cancel,
                }
                go func() {
                        for blk := range blockEpoch.Epochs {
                                ntfn := blockntfns.NewBlockConnected(
                                        *blk.BlockHeader,
                                        uint32(blk.Height),
                                )

                                sub.Notifications <- ntfn
                        }
                }()

                return &sub, nil
        }
}

// walletReBroadcaster is a simple wrapper around the pushtx.Broadcaster
// interface to adhere to the expanded lnwallet.Rebroadcaster interface.
type walletReBroadcaster struct {
        started atomic.Bool

        *pushtx.Broadcaster
}

// newWalletReBroadcaster creates a new instance of the walletReBroadcaster.
func newWalletReBroadcaster(
        broadcaster *pushtx.Broadcaster) *walletReBroadcaster {

        return &walletReBroadcaster{
                Broadcaster: broadcaster,
        }
}

// Start launches all goroutines the rebroadcaster needs to operate.
func (w *walletReBroadcaster) Start() error {
        defer w.started.Store(true)

        return w.Broadcaster.Start()
}

// Started returns true if the broadcaster is already active.
func (w *walletReBroadcaster) Started() bool {
        return w.started.Load()
}

// BuildChainControl is responsible for creating a fully populated chain
// control instance from a wallet.
//
// NOTE: This is part of the ChainControlBuilder interface.
func (d *DefaultWalletImpl) BuildChainControl(
        partialChainControl *chainreg.PartialChainControl,
        walletConfig *btcwallet.Config) (*chainreg.ChainControl, func(), error) {

        walletController, err := btcwallet.New(
                *walletConfig, partialChainControl.Cfg.BlockCache,
        )
        if err != nil {
                err := fmt.Errorf("unable to create wallet controller: %w", err)
                d.logger.Error(err)
                return nil, nil, err
        }

        keyRing := keychain.NewBtcWalletKeyRing(
                walletController.InternalWallet(), walletConfig.CoinType,
        )

        // Create, and start the lnwallet, which handles the core payment
        // channel logic, and exposes control via proxy state machines.
        lnWalletConfig := lnwallet.Config{
                Database:              partialChainControl.Cfg.ChanStateDB,
                Notifier:              partialChainControl.ChainNotifier,
                WalletController:      walletController,
                Signer:                walletController,
                FeeEstimator:          partialChainControl.FeeEstimator,
                SecretKeyRing:         keyRing,
                ChainIO:               walletController,
                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
        // don't want to create a rebroadcast loop.
        if partialChainControl.Cfg.NeutrinoCS == nil {
                cs := partialChainControl.ChainSource
                broadcastCfg := pushtx.Config{
                        Broadcast: func(tx *wire.MsgTx) error {
                                _, err := cs.SendRawTransaction(
                                        tx, true,
                                )

                                return err
                        },
                        SubscribeBlocks: proxyBlockEpoch(
                                partialChainControl.ChainNotifier,
                        ),
                        RebroadcastInterval: pushtx.DefaultRebroadcastInterval,
                        // In case the backend is different from neutrino we
                        // make sure that broadcast backend errors are mapped
                        // to the neutrino broadcastErr.
                        MapCustomBroadcastError: func(err error) error {
                                rpcErr := cs.MapRPCErr(err)
                                return broadcastErrorMapper(rpcErr)
                        },
                }

                lnWalletConfig.Rebroadcaster = newWalletReBroadcaster(
                        pushtx.NewBroadcaster(&broadcastCfg),
                )
        }

        // We've created the wallet configuration now, so we can finish
        // initializing the main chain control.
        activeChainControl, cleanUp, err := chainreg.NewChainControl(
                lnWalletConfig, walletController, partialChainControl,
        )
        if err != nil {
                err := fmt.Errorf("unable to create chain control: %w", err)
                d.logger.Error(err)
                return nil, nil, err
        }

        return activeChainControl, cleanUp, nil
}

// RPCSignerWalletImpl is a wallet implementation that uses a remote signer over
// an RPC interface.
type RPCSignerWalletImpl struct {
        // DefaultWalletImpl is the embedded instance of the default
        // implementation that the remote signer uses as its watch-only wallet
        // for keeping track of addresses and UTXOs.
        *DefaultWalletImpl
}

// NewRPCSignerWalletImpl creates a new instance of the remote signing wallet
// implementation.
func NewRPCSignerWalletImpl(cfg *Config, logger btclog.Logger,
        interceptor signal.Interceptor,
        migrateWatchOnly bool) *RPCSignerWalletImpl {

        return &RPCSignerWalletImpl{
                DefaultWalletImpl: &DefaultWalletImpl{
                        cfg:              cfg,
                        logger:           logger,
                        interceptor:      interceptor,
                        watchOnly:        true,
                        migrateWatchOnly: migrateWatchOnly,
                        pwService:        createWalletUnlockerService(cfg),
                },
        }
}

// BuildChainControl is responsible for creating or unlocking and then fully
// initializing a wallet and returning it as part of a fully populated chain
// control instance.
//
// NOTE: This is part of the ChainControlBuilder interface.
func (d *RPCSignerWalletImpl) BuildChainControl(
        partialChainControl *chainreg.PartialChainControl,
        walletConfig *btcwallet.Config) (*chainreg.ChainControl, func(), error) {

        walletController, err := btcwallet.New(
                *walletConfig, partialChainControl.Cfg.BlockCache,
        )
        if err != nil {
                err := fmt.Errorf("unable to create wallet controller: %w", err)
                d.logger.Error(err)
                return nil, nil, err
        }

        baseKeyRing := keychain.NewBtcWalletKeyRing(
                walletController.InternalWallet(), walletConfig.CoinType,
        )

        rpcKeyRing, err := rpcwallet.NewRPCKeyRing(
                baseKeyRing, walletController,
                d.DefaultWalletImpl.cfg.RemoteSigner, walletConfig.NetParams,
        )
        if err != nil {
                err := fmt.Errorf("unable to create RPC remote signing wallet "+
                        "%v", err)
                d.logger.Error(err)
                return nil, nil, err
        }

        // Create, and start the lnwallet, which handles the core payment
        // channel logic, and exposes control via proxy state machines.
        lnWalletConfig := lnwallet.Config{
                Database:              partialChainControl.Cfg.ChanStateDB,
                Notifier:              partialChainControl.ChainNotifier,
                WalletController:      rpcKeyRing,
                Signer:                rpcKeyRing,
                FeeEstimator:          partialChainControl.FeeEstimator,
                SecretKeyRing:         rpcKeyRing,
                ChainIO:               walletController,
                NetParams:             *walletConfig.NetParams,
                CoinSelectionStrategy: walletConfig.CoinSelectionStrategy,
        }

        // We've created the wallet configuration now, so we can finish
        // initializing the main chain control.
        activeChainControl, cleanUp, err := chainreg.NewChainControl(
                lnWalletConfig, rpcKeyRing, partialChainControl,
        )
        if err != nil {
                err := fmt.Errorf("unable to create chain control: %w", err)
                d.logger.Error(err)
                return nil, nil, err
        }

        return activeChainControl, cleanUp, nil
}

// DatabaseInstances is a struct that holds all instances to the actual
// databases that are used in lnd.
type DatabaseInstances struct {
        // GraphDB is the database that stores the channel graph used for path
        // finding.
        GraphDB *graphdb.ChannelGraph

        // ChanStateDB is the database that stores all of our node's channel
        // state.
        ChanStateDB *channeldb.DB

        // HeightHintDB is the database that stores height hints for spends.
        HeightHintDB kvdb.Backend

        // InvoiceDB is the database that stores information about invoices.
        InvoiceDB invoices.InvoiceDB

        // MacaroonDB is the database that stores macaroon root keys.
        MacaroonDB kvdb.Backend

        // DecayedLogDB is the database that stores p2p related encryption
        // information.
        DecayedLogDB kvdb.Backend

        // TowerClientDB is the database that stores the watchtower client's
        // configuration.
        TowerClientDB wtclient.DB

        // TowerServerDB is the database that stores the watchtower server's
        // configuration.
        TowerServerDB watchtower.DB

        // WalletDB is the configuration for loading the wallet database using
        // the btcwallet's loader.
        WalletDB btcwallet.LoaderOption

        // NativeSQLStore is a pointer to a native SQL store that can be used
        // 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
}

// DefaultDatabaseBuilder is a type that builds the default database backends
// for lnd, using the given configuration to decide what actual implementation
// to use.
type DefaultDatabaseBuilder struct {
        cfg    *Config
        logger btclog.Logger
}

// NewDefaultDatabaseBuilder returns a new instance of the default database
// builder.
func NewDefaultDatabaseBuilder(cfg *Config,
        logger btclog.Logger) *DefaultDatabaseBuilder {

        return &DefaultDatabaseBuilder{
                cfg:    cfg,
                logger: logger,
        }
}

// BuildDatabase extracts the current databases that we'll use for normal
// operation in the daemon. A function closure that closes all opened databases
// is also returned.
func (d *DefaultDatabaseBuilder) BuildDatabase(
        ctx context.Context) (*DatabaseInstances, func(), error) {

        d.logger.Infof("Opening the main database, this might take a few " +
                "minutes...")

        cfg := d.cfg
        if cfg.DB.Backend == lncfg.BoltBackend {
                d.logger.Infof("Opening bbolt database, sync_freelist=%v, "+
                        "auto_compact=%v", !cfg.DB.Bolt.NoFreelistSync,
                        cfg.DB.Bolt.AutoCompact)
        }

        startOpenTime := time.Now()

        databaseBackends, err := cfg.DB.GetBackends(
                ctx, cfg.graphDatabaseDir(), cfg.networkDir, filepath.Join(
                        cfg.Watchtower.TowerDir, BitcoinChainName,
                        lncfg.NormalizeNetwork(cfg.ActiveNetParams.Name),
                ), cfg.WtClient.Active, cfg.Watchtower.Active, d.logger,
        )
        if err != nil {
                return nil, nil, fmt.Errorf("unable to obtain database "+
                        "backends: %v", err)
        }

        // With the full remote mode we made sure both the graph and channel
        // state DB point to the same local or remote DB and the same namespace
        // within that DB.
        dbs := &DatabaseInstances{
                HeightHintDB:   databaseBackends.HeightHintDB,
                MacaroonDB:     databaseBackends.MacaroonDB,
                DecayedLogDB:   databaseBackends.DecayedLogDB,
                WalletDB:       databaseBackends.WalletDB,
                NativeSQLStore: databaseBackends.NativeSQLStore,
        }
        cleanUp := func() {
                // We can just close the returned close functions directly. Even
                // if we decorate the channel DB with an additional struct, its
                // close function still just points to the kvdb backend.
                for name, closeFunc := range databaseBackends.CloseFuncs {
                        if err := closeFunc(); err != nil {
                                d.logger.Errorf("Error closing %s "+
                                        "database: %v", name, err)
                        }
                }
        }
        if databaseBackends.Remote {
                d.logger.Infof("Using remote %v database! Creating "+
                        "graph and channel state DB instances", cfg.DB.Backend)
        } else {
                d.logger.Infof("Creating local graph and channel state DB " +
                        "instances")
        }

        graphDBOptions := []graphdb.OptionModifier{
                graphdb.WithRejectCacheSize(cfg.Caches.RejectCacheSize),
                graphdb.WithChannelCacheSize(cfg.Caches.ChannelCacheSize),
                graphdb.WithBatchCommitInterval(cfg.DB.BatchCommitInterval),
                graphdb.WithUseGraphCache(!cfg.DB.NoGraphCache),
        }

        // We want to pre-allocate the channel graph cache according to what we
        // expect for mainnet to speed up memory allocation.
        if cfg.ActiveNetParams.Name == chaincfg.MainNetParams.Name {
                graphDBOptions = append(
                        graphDBOptions, graphdb.WithPreAllocCacheNumNodes(
                                graphdb.DefaultPreAllocCacheNumNodes,
                        ),
                )
        }

        dbs.GraphDB, err = graphdb.NewChannelGraph(
                databaseBackends.GraphDB, graphDBOptions...,
        )
        if err != nil {
                cleanUp()

                err := fmt.Errorf("unable to open graph DB: %w", err)
                d.logger.Error(err)

                return nil, nil, err
        }

        dbOptions := []channeldb.OptionModifier{
                channeldb.OptionDryRunMigration(cfg.DryRunMigration),
                channeldb.OptionKeepFailedPaymentAttempts(
                        cfg.KeepFailedPaymentAttempts,
                ),
                channeldb.OptionStoreFinalHtlcResolutions(
                        cfg.StoreFinalHtlcResolutions,
                ),
                channeldb.OptionPruneRevocationLog(cfg.DB.PruneRevocation),
                channeldb.OptionNoRevLogAmtData(cfg.DB.NoRevLogAmtData),
        }

        // Otherwise, we'll open two instances, one for the state we only need
        // locally, and the other for things we want to ensure are replicated.
        dbs.ChanStateDB, err = channeldb.CreateWithBackend(
                databaseBackends.ChanStateDB, dbOptions...,
        )
        switch {
        // Give the DB a chance to dry run the migration. Since we know that
        // both the channel state and graph DBs are still always behind the same
        // backend, we know this would be applied to both of those DBs.
        case err == channeldb.ErrDryRunMigrationOK:
                d.logger.Infof("Channel DB dry run migration successful")
                return nil, nil, err

        case err != nil:
                cleanUp()

                err := fmt.Errorf("unable to open graph DB: %w", err)
                d.logger.Error(err)
                return nil, nil, err
        }

        // Instantiate a native SQL invoice store if the flag is set.
        if d.cfg.DB.UseNativeSQL {
                // KV invoice db resides in the same database as the channel
                // state DB. Let's query the database to see if we have any
                // invoices there. If we do, we won't allow the user to start
                // lnd with native SQL enabled, as we don't currently migrate
                // the invoices to the new database schema.
                invoiceSlice, err := dbs.ChanStateDB.QueryInvoices(
                        ctx, invoices.InvoiceQuery{
                                NumMaxInvoices: 1,
                        },
                )
                if err != nil {
                        cleanUp()
                        d.logger.Errorf("Unable to query KV invoice DB: %v",
                                err)

                        return nil, nil, err
                }

                if len(invoiceSlice.Invoices) > 0 {
                        cleanUp()
                        err := fmt.Errorf("found invoices in the KV invoice " +
                                "DB, migration to native SQL is not yet " +
                                "supported")
                        d.logger.Error(err)

                        return nil, nil, err
                }

                executor := sqldb.NewTransactionExecutor(
                        dbs.NativeSQLStore,
                        func(tx *sql.Tx) invoices.SQLInvoiceQueries {
                                return dbs.NativeSQLStore.WithTx(tx)
                        },
                )

                dbs.InvoiceDB = invoices.NewSQLStore(
                        executor, clock.NewDefaultClock(),
                )
        } else {
                dbs.InvoiceDB = dbs.ChanStateDB
        }

        // Wrap the watchtower client DB and make sure we clean up.
        if cfg.WtClient.Active {
                dbs.TowerClientDB, err = wtdb.OpenClientDB(
                        databaseBackends.TowerClientDB,
                )
                if err != nil {
                        cleanUp()

                        err := fmt.Errorf("unable to open %s database: %w",
                                lncfg.NSTowerClientDB, err)
                        d.logger.Error(err)
                        return nil, nil, err
                }
        }

        // Wrap the watchtower server DB and make sure we clean up.
        if cfg.Watchtower.Active {
                dbs.TowerServerDB, err = wtdb.OpenTowerDB(
                        databaseBackends.TowerServerDB,
                )
                if err != nil {
                        cleanUp()

                        err := fmt.Errorf("unable to open %s database: %w",
                                lncfg.NSTowerServerDB, err)
                        d.logger.Error(err)
                        return nil, nil, err
                }
        }

        openTime := time.Since(startOpenTime)
        d.logger.Infof("Database(s) now open (time_to_open=%v)!", openTime)

        return dbs, cleanUp, nil
}

// waitForWalletPassword blocks until a password is provided by the user to
// this RPC server.
func waitForWalletPassword(cfg *Config,
        pwService *walletunlocker.UnlockerService,
        loaderOpts []btcwallet.LoaderOption, shutdownChan <-chan struct{}) (
        *walletunlocker.WalletUnlockParams, error) {

        // Wait for user to provide the password.
        ltndLog.Infof("Waiting for wallet encryption password. Use `lncli " +
                "create` to create a wallet, `lncli unlock` to unlock an " +
                "existing wallet, or `lncli changepassword` to change the " +
                "password of an existing wallet and unlock it.")

        // We currently don't distinguish between getting a password to be used
        // for creation or unlocking, as a new wallet db will be created if
        // none exists when creating the chain control.
        select {
        // The wallet is being created for the first time, we'll check to see
        // if the user provided any entropy for seed creation. If so, then
        // we'll create the wallet early to load the seed.
        case initMsg := <-pwService.InitMsgs:
                password := initMsg.Passphrase
                cipherSeed := initMsg.WalletSeed
                extendedKey := initMsg.WalletExtendedKey
                watchOnlyAccounts := initMsg.WatchOnlyAccounts
                recoveryWindow := initMsg.RecoveryWindow

                // Before we proceed, we'll check the internal version of the
                // seed. If it's greater than the current key derivation
                // version, then we'll return an error as we don't understand
                // this.
                if cipherSeed != nil &&
                        !keychain.IsKnownVersion(cipherSeed.InternalVersion) {

                        return nil, fmt.Errorf("invalid internal "+
                                "seed version %v, current max version is %v",
                                cipherSeed.InternalVersion,
                                keychain.CurrentKeyDerivationVersion)
                }

                loader, err := btcwallet.NewWalletLoader(
                        cfg.ActiveNetParams.Params, recoveryWindow,
                        loaderOpts...,
                )
                if err != nil {
                        return nil, err
                }

                // With the seed, we can now use the wallet loader to create
                // the wallet, then pass it back to avoid unlocking it again.
                var (
                        birthday  time.Time
                        newWallet *wallet.Wallet
                )
                switch {
                // A normal cipher seed was given, use the birthday encoded in
                // it and create the wallet from that.
                case cipherSeed != nil:
                        birthday = cipherSeed.BirthdayTime()
                        newWallet, err = loader.CreateNewWallet(
                                password, password, cipherSeed.Entropy[:],
                                birthday,
                        )

                // No seed was given, we're importing a wallet from its extended
                // private key.
                case extendedKey != nil:
                        birthday = initMsg.ExtendedKeyBirthday
                        newWallet, err = loader.CreateNewWalletExtendedKey(
                                password, password, extendedKey, birthday,
                        )

                // Neither seed nor extended private key was given, so maybe the
                // third option was chosen, the watch-only initialization. In
                // this case we need to import each of the xpubs individually.
                case watchOnlyAccounts != nil:
                        if !cfg.RemoteSigner.Enable {
                                return nil, fmt.Errorf("cannot initialize " +
                                        "watch only wallet with remote " +
                                        "signer config disabled")
                        }

                        birthday = initMsg.WatchOnlyBirthday
                        newWallet, err = loader.CreateNewWatchingOnlyWallet(
                                password, birthday,
                        )
                        if err != nil {
                                break
                        }

                        err = importWatchOnlyAccounts(newWallet, initMsg)

                default:
                        // The unlocker service made sure either the cipher seed
                        // or the extended key is set so, we shouldn't get here.
                        // The default case is just here for readability and
                        // completeness.
                        err = fmt.Errorf("cannot create wallet, neither seed " +
                                "nor extended key was given")
                }
                if err != nil {
                        // Don't leave the file open in case the new wallet
                        // could not be created for whatever reason.
                        if err := loader.UnloadWallet(); err != nil {
                                ltndLog.Errorf("Could not unload new "+
                                        "wallet: %v", err)
                        }
                        return nil, err
                }

                // For new wallets, the ResetWalletTransactions flag is a no-op.
                if cfg.ResetWalletTransactions {
                        ltndLog.Warnf("Ignoring reset-wallet-transactions " +
                                "flag for new wallet as it has no effect")
                }

                return &walletunlocker.WalletUnlockParams{
                        Password:        password,
                        Birthday:        birthday,
                        RecoveryWindow:  recoveryWindow,
                        Wallet:          newWallet,
                        ChansToRestore:  initMsg.ChanBackups,
                        UnloadWallet:    loader.UnloadWallet,
                        StatelessInit:   initMsg.StatelessInit,
                        MacResponseChan: pwService.MacResponseChan,
                        MacRootKey:      initMsg.MacRootKey,
                }, nil

        // The wallet has already been created in the past, and is simply being
        // unlocked. So we'll just return these passphrases.
        case unlockMsg := <-pwService.UnlockMsgs:
                // Resetting the transactions is something the user likely only
                // wants to do once so we add a prominent warning to the log to
                // remind the user to turn off the setting again after
                // successful completion.
                if cfg.ResetWalletTransactions {
                        ltndLog.Warnf("Dropped all transaction history from " +
                                "on-chain wallet. Remember to disable " +
                                "reset-wallet-transactions flag for next " +
                                "start of lnd")
                }

                return &walletunlocker.WalletUnlockParams{
                        Password:        unlockMsg.Passphrase,
                        RecoveryWindow:  unlockMsg.RecoveryWindow,
                        Wallet:          unlockMsg.Wallet,
                        ChansToRestore:  unlockMsg.ChanBackups,
                        UnloadWallet:    unlockMsg.UnloadWallet,
                        StatelessInit:   unlockMsg.StatelessInit,
                        MacResponseChan: pwService.MacResponseChan,
                }, nil

        // If we got a shutdown signal we just return with an error immediately
        case <-shutdownChan:
                return nil, fmt.Errorf("shutting down")
        }
}

// importWatchOnlyAccounts imports all individual account xpubs into our wallet
// which we created as watch-only.
func importWatchOnlyAccounts(wallet *wallet.Wallet,
        initMsg *walletunlocker.WalletInitMsg) error {

        scopes := make([]waddrmgr.ScopedIndex, 0, len(initMsg.WatchOnlyAccounts))
        for scope := range initMsg.WatchOnlyAccounts {
                scopes = append(scopes, scope)
        }

        // We need to import the accounts in the correct order, otherwise the
        // indices will be incorrect.
        sort.Slice(scopes, func(i, j int) bool {
                return scopes[i].Scope.Purpose < scopes[j].Scope.Purpose ||
                        scopes[i].Index < scopes[j].Index
        })

        for _, scope := range scopes {
                addrSchema := waddrmgr.ScopeAddrMap[waddrmgr.KeyScopeBIP0084]

                // We want witness pubkey hash by default, except for BIP49
                // where we want mixed and BIP86 where we want taproot address
                // formats.
                switch scope.Scope.Purpose {
                case waddrmgr.KeyScopeBIP0049Plus.Purpose,
                        waddrmgr.KeyScopeBIP0086.Purpose:

                        addrSchema = waddrmgr.ScopeAddrMap[scope.Scope]
                }

                // We want a human-readable account name. But for the default
                // on-chain wallet we actually need to call it "default" to make
                // sure everything works correctly.
                name := fmt.Sprintf("%s/%d'", scope.Scope.String(), scope.Index)
                if scope.Index == 0 {
                        name = "default"
                }

                _, err := wallet.ImportAccountWithScope(
                        name, initMsg.WatchOnlyAccounts[scope],
                        initMsg.WatchOnlyMasterFingerprint, scope.Scope,
                        addrSchema,
                )
                if err != nil {
                        return fmt.Errorf("could not import account %v: %w",
                                name, err)
                }
        }

        return nil
}

// initNeutrinoBackend inits a new instance of the neutrino light client
// backend given a target chain directory to store the chain state.
func initNeutrinoBackend(ctx context.Context, cfg *Config, chainDir string,
        blockCache *blockcache.BlockCache) (*neutrino.ChainService,
        func(), error) {

        // Both channel validation flags are false by default but their meaning
        // is the inverse of each other. Therefore both cannot be true. For
        // every other case, the neutrino.validatechannels overwrites the
        // routing.assumechanvalid value.
        if cfg.NeutrinoMode.ValidateChannels && cfg.Routing.AssumeChannelValid {
                return nil, nil, fmt.Errorf("can't set both " +
                        "neutrino.validatechannels and routing." +
                        "assumechanvalid to true at the same time")
        }
        cfg.Routing.AssumeChannelValid = !cfg.NeutrinoMode.ValidateChannels

        // First we'll open the database file for neutrino, creating the
        // database if needed. We append the normalized network name here to
        // match the behavior of btcwallet.
        dbPath := filepath.Join(
                chainDir, lncfg.NormalizeNetwork(cfg.ActiveNetParams.Name),
        )

        // Ensure that the neutrino db path exists.
        if err := os.MkdirAll(dbPath, 0700); err != nil {
                return nil, nil, err
        }

        var (
                db  walletdb.DB
                err error
        )
        switch {
        case cfg.DB.Backend == kvdb.SqliteBackendName:
                sqliteConfig := lncfg.GetSqliteConfigKVDB(cfg.DB.Sqlite)
                db, err = kvdb.Open(
                        kvdb.SqliteBackendName, ctx, sqliteConfig, dbPath,
                        lncfg.SqliteNeutrinoDBName, lncfg.NSNeutrinoDB,
                )

        default:
                dbName := filepath.Join(dbPath, "neutrino.db")
                db, err = walletdb.Create(
                        "bdb", dbName, !cfg.SyncFreelist, cfg.DB.Bolt.DBTimeout,
                )
        }
        if err != nil {
                return nil, nil, fmt.Errorf("unable to create "+
                        "neutrino database: %v", err)
        }

        headerStateAssertion, err := parseHeaderStateAssertion(
                cfg.NeutrinoMode.AssertFilterHeader,
        )
        if err != nil {
                db.Close()
                return nil, nil, err
        }

        // With the database open, we can now create an instance of the
        // neutrino light client. We pass in relevant configuration parameters
        // required.
        config := neutrino.Config{
                DataDir:      dbPath,
                Database:     db,
                ChainParams:  *cfg.ActiveNetParams.Params,
                AddPeers:     cfg.NeutrinoMode.AddPeers,
                ConnectPeers: cfg.NeutrinoMode.ConnectPeers,
                Dialer: func(addr net.Addr) (net.Conn, error) {
                        return cfg.net.Dial(
                                addr.Network(), addr.String(),
                                cfg.ConnectionTimeout,
                        )
                },
                NameResolver: func(host string) ([]net.IP, error) {
                        addrs, err := cfg.net.LookupHost(host)
                        if err != nil {
                                return nil, err
                        }

                        ips := make([]net.IP, 0, len(addrs))
                        for _, strIP := range addrs {
                                ip := net.ParseIP(strIP)
                                if ip == nil {
                                        continue
                                }

                                ips = append(ips, ip)
                        }

                        return ips, nil
                },
                AssertFilterHeader: headerStateAssertion,
                BlockCache:         blockCache.Cache,
                BroadcastTimeout:   cfg.NeutrinoMode.BroadcastTimeout,
                PersistToDisk:      cfg.NeutrinoMode.PersistFilters,
        }

        neutrino.MaxPeers = 8
        neutrino.BanDuration = time.Hour * 48
        neutrino.UserAgentName = cfg.NeutrinoMode.UserAgentName
        neutrino.UserAgentVersion = cfg.NeutrinoMode.UserAgentVersion

        neutrinoCS, err := neutrino.NewChainService(config)
        if err != nil {
                db.Close()
                return nil, nil, fmt.Errorf("unable to create neutrino light "+
                        "client: %v", err)
        }

        if err := neutrinoCS.Start(); err != nil {
                db.Close()
                return nil, nil, err
        }

        cleanUp := func() {
                if err := neutrinoCS.Stop(); err != nil {
                        ltndLog.Infof("Unable to stop neutrino light client: "+
                                "%v", err)
                }
                db.Close()
        }

        return neutrinoCS, cleanUp, nil
}

// parseHeaderStateAssertion parses the user-specified neutrino header state
// into a headerfs.FilterHeader.
func parseHeaderStateAssertion(state string) (*headerfs.FilterHeader, error) {
        if len(state) == 0 {
                return nil, nil
        }

        split := strings.Split(state, ":")
        if len(split) != 2 {
                return nil, fmt.Errorf("header state assertion %v in "+
                        "unexpected format, expected format height:hash", state)
        }

        height, err := strconv.ParseUint(split[0], 10, 32)
        if err != nil {
                return nil, fmt.Errorf("invalid filter header height: %w", err)
        }

        hash, err := chainhash.NewHashFromStr(split[1])
        if err != nil {
                return nil, fmt.Errorf("invalid filter header hash: %w", err)
        }

        return &headerfs.FilterHeader{
                Height:     uint32(height),
                FilterHash: *hash,
        }, nil
}

// broadcastErrorMapper maps errors from bitcoin backends other than neutrino to
// the neutrino BroadcastError which allows the Rebroadcaster which currently
// resides in the neutrino package to use all of its functionalities.
func broadcastErrorMapper(err error) error {
        var returnErr error

        // We only filter for specific backend errors which are relevant for the
        // Rebroadcaster.
        switch {
        // This makes sure the tx is removed from the rebroadcaster once it is
        // confirmed.
        case errors.Is(err, chain.ErrTxAlreadyKnown),
                errors.Is(err, chain.ErrTxAlreadyConfirmed):

                returnErr = &pushtx.BroadcastError{
                        Code:   pushtx.Confirmed,
                        Reason: err.Error(),
                }

        // Transactions which are still in mempool but might fall out because
        // of low fees are rebroadcasted despite of their backend error.
        case errors.Is(err, chain.ErrTxAlreadyInMempool):
                returnErr = &pushtx.BroadcastError{
                        Code:   pushtx.Mempool,
                        Reason: err.Error(),
                }

        // Transactions which are not accepted into mempool because of low fees
        // in the first place are rebroadcasted despite of their backend error.
        // Mempool conditions change over time so it makes sense to retry
        // publishing the transaction. Moreover we log the detailed error so the
        // user can intervene and increase the size of his mempool.
        case errors.Is(err, chain.ErrMempoolMinFeeNotMet):
                ltndLog.Warnf("Error while broadcasting transaction: %v", err)

                returnErr = &pushtx.BroadcastError{
                        Code:   pushtx.Mempool,
                        Reason: err.Error(),
                }
        }

        return returnErr
}

lightningnetwork / lnd / 12583319996

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