lnd.xprv/chainregistry.go

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2019-01-24 16:28:25 +03:00
package lnd
import (
"encoding/hex"
"fmt"
"io/ioutil"
"net"
"os"
"path/filepath"
"strconv"
"strings"
"sync"
"time"
"github.com/btcsuite/btcd/chaincfg/chainhash"
"github.com/btcsuite/btcd/rpcclient"
"github.com/btcsuite/btcutil"
"github.com/btcsuite/btcwallet/chain"
"github.com/btcsuite/btcwallet/wallet"
"github.com/btcsuite/btcwallet/walletdb"
"github.com/lightninglabs/neutrino"
"github.com/lightningnetwork/lnd/chainntnfs"
"github.com/lightningnetwork/lnd/chainntnfs/bitcoindnotify"
"github.com/lightningnetwork/lnd/chainntnfs/btcdnotify"
"github.com/lightningnetwork/lnd/chainntnfs/neutrinonotify"
"github.com/lightningnetwork/lnd/channeldb"
"github.com/lightningnetwork/lnd/htlcswitch"
"github.com/lightningnetwork/lnd/input"
"github.com/lightningnetwork/lnd/keychain"
"github.com/lightningnetwork/lnd/lnwallet"
"github.com/lightningnetwork/lnd/lnwallet/btcwallet"
"github.com/lightningnetwork/lnd/lnwire"
"github.com/lightningnetwork/lnd/routing/chainview"
)
const (
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defaultBitcoinMinHTLCMSat = lnwire.MilliSatoshi(1000)
// DefaultBitcoinBaseFeeMSat is the default forwarding base fee.
DefaultBitcoinBaseFeeMSat = lnwire.MilliSatoshi(1000)
// DefaultBitcoinFeeRate is the default forwarding fee rate.
DefaultBitcoinFeeRate = lnwire.MilliSatoshi(1)
// DefaultBitcoinTimeLockDelta is the default forwarding time lock
// delta.
DefaultBitcoinTimeLockDelta = 40
defaultLitecoinMinHTLCMSat = lnwire.MilliSatoshi(1000)
defaultLitecoinBaseFeeMSat = lnwire.MilliSatoshi(1000)
defaultLitecoinFeeRate = lnwire.MilliSatoshi(1)
defaultLitecoinTimeLockDelta = 576
defaultLitecoinDustLimit = btcutil.Amount(54600)
// defaultBitcoinStaticFeePerKW is the fee rate of 50 sat/vbyte
// expressed in sat/kw.
defaultBitcoinStaticFeePerKW = lnwallet.SatPerKWeight(12500)
// defaultLitecoinStaticFeePerKW is the fee rate of 200 sat/vbyte
// expressed in sat/kw.
defaultLitecoinStaticFeePerKW = lnwallet.SatPerKWeight(50000)
// btcToLtcConversionRate is a fixed ratio used in order to scale up
// payments when running on the Litecoin chain.
btcToLtcConversionRate = 60
)
// defaultBtcChannelConstraints is the default set of channel constraints that are
// meant to be used when initially funding a Bitcoin channel.
//
// TODO(halseth): make configurable at startup?
var defaultBtcChannelConstraints = channeldb.ChannelConstraints{
DustLimit: lnwallet.DefaultDustLimit(),
MaxAcceptedHtlcs: input.MaxHTLCNumber / 2,
}
// defaultLtcChannelConstraints is the default set of channel constraints that are
// meant to be used when initially funding a Litecoin channel.
var defaultLtcChannelConstraints = channeldb.ChannelConstraints{
DustLimit: defaultLitecoinDustLimit,
MaxAcceptedHtlcs: input.MaxHTLCNumber / 2,
}
// chainCode is an enum-like structure for keeping track of the chains
// currently supported within lnd.
type chainCode uint32
const (
// bitcoinChain is Bitcoin's testnet chain.
bitcoinChain chainCode = iota
// litecoinChain is Litecoin's testnet chain.
litecoinChain
)
// String returns a string representation of the target chainCode.
func (c chainCode) String() string {
switch c {
case bitcoinChain:
return "bitcoin"
case litecoinChain:
return "litecoin"
default:
return "kekcoin"
}
}
// chainControl couples the three primary interfaces lnd utilizes for a
// particular chain together. A single chainControl instance will exist for all
// the chains lnd is currently active on.
type chainControl struct {
chainIO lnwallet.BlockChainIO
feeEstimator lnwallet.FeeEstimator
signer input.Signer
keyRing keychain.SecretKeyRing
wc lnwallet.WalletController
msgSigner lnwallet.MessageSigner
chainNotifier chainntnfs.ChainNotifier
chainView chainview.FilteredChainView
wallet *lnwallet.LightningWallet
routingPolicy htlcswitch.ForwardingPolicy
}
// newChainControlFromConfig attempts to create a chainControl instance
// according to the parameters in the passed lnd configuration. Currently three
// branches of chainControl instances exist: one backed by a running btcd
// full-node, another backed by a running bitcoind full-node, and the other
// backed by a running neutrino light client instance. When running with a
// neutrino light client instance, `neutrinoCS` must be non-nil.
func newChainControlFromConfig(cfg *config, chanDB *channeldb.DB,
privateWalletPw, publicWalletPw []byte, birthday time.Time,
recoveryWindow uint32, wallet *wallet.Wallet,
neutrinoCS *neutrino.ChainService) (*chainControl, error) {
// Set the RPC config from the "home" chain. Multi-chain isn't yet
// active, so we'll restrict usage to a particular chain for now.
homeChainConfig := cfg.Bitcoin
if registeredChains.PrimaryChain() == litecoinChain {
homeChainConfig = cfg.Litecoin
}
ltndLog.Infof("Primary chain is set to: %v",
registeredChains.PrimaryChain())
cc := &chainControl{}
switch registeredChains.PrimaryChain() {
case bitcoinChain:
cc.routingPolicy = htlcswitch.ForwardingPolicy{
MinHTLC: cfg.Bitcoin.MinHTLC,
BaseFee: cfg.Bitcoin.BaseFee,
FeeRate: cfg.Bitcoin.FeeRate,
TimeLockDelta: cfg.Bitcoin.TimeLockDelta,
}
cc.feeEstimator = lnwallet.NewStaticFeeEstimator(
defaultBitcoinStaticFeePerKW, 0,
)
case litecoinChain:
cc.routingPolicy = htlcswitch.ForwardingPolicy{
MinHTLC: cfg.Litecoin.MinHTLC,
BaseFee: cfg.Litecoin.BaseFee,
FeeRate: cfg.Litecoin.FeeRate,
TimeLockDelta: cfg.Litecoin.TimeLockDelta,
}
cc.feeEstimator = lnwallet.NewStaticFeeEstimator(
defaultLitecoinStaticFeePerKW, 0,
)
default:
return nil, fmt.Errorf("Default routing policy for chain %v is "+
"unknown", registeredChains.PrimaryChain())
}
walletConfig := &btcwallet.Config{
PrivatePass: privateWalletPw,
PublicPass: publicWalletPw,
Birthday: birthday,
RecoveryWindow: recoveryWindow,
DataDir: homeChainConfig.ChainDir,
NetParams: activeNetParams.Params,
CoinType: activeNetParams.CoinType,
Wallet: wallet,
}
var err error
// Initialize the height hint cache within the chain directory.
hintCache, err := chainntnfs.NewHeightHintCache(chanDB)
if err != nil {
return nil, fmt.Errorf("unable to initialize height hint "+
"cache: %v", err)
}
// If spv mode is active, then we'll be using a distinct set of
// chainControl interfaces that interface directly with the p2p network
// of the selected chain.
switch homeChainConfig.Node {
case "neutrino":
// We'll create ChainNotifier and FilteredChainView instances,
// along with the wallet's ChainSource, which are all backed by
// the neutrino light client.
cc.chainNotifier = neutrinonotify.New(
neutrinoCS, hintCache, hintCache,
)
cc.chainView, err = chainview.NewCfFilteredChainView(neutrinoCS)
if err != nil {
return nil, err
}
// If the user provided an API for fee estimation, activate it now.
if cfg.NeutrinoMode.FeeURL != "" {
ltndLog.Infof("Using API fee estimator!")
estimator := lnwallet.NewWebAPIFeeEstimator(
lnwallet.SparseConfFeeSource{
URL: cfg.NeutrinoMode.FeeURL,
},
defaultBitcoinStaticFeePerKW,
)
if err := estimator.Start(); err != nil {
return nil, err
}
cc.feeEstimator = estimator
}
walletConfig.ChainSource = chain.NewNeutrinoClient(
activeNetParams.Params, neutrinoCS,
)
case "bitcoind", "litecoind":
var bitcoindMode *bitcoindConfig
switch {
case cfg.Bitcoin.Active:
bitcoindMode = cfg.BitcoindMode
case cfg.Litecoin.Active:
bitcoindMode = cfg.LitecoindMode
}
// Otherwise, we'll be speaking directly via RPC and ZMQ to a
// bitcoind node. If the specified host for the btcd/ltcd RPC
// server already has a port specified, then we use that
// directly. Otherwise, we assume the default port according to
// the selected chain parameters.
var bitcoindHost string
if strings.Contains(bitcoindMode.RPCHost, ":") {
bitcoindHost = bitcoindMode.RPCHost
} else {
// The RPC ports specified in chainparams.go assume
// btcd, which picks a different port so that btcwallet
// can use the same RPC port as bitcoind. We convert
// this back to the btcwallet/bitcoind port.
rpcPort, err := strconv.Atoi(activeNetParams.rpcPort)
if err != nil {
return nil, err
}
rpcPort -= 2
bitcoindHost = fmt.Sprintf("%v:%d",
bitcoindMode.RPCHost, rpcPort)
if (cfg.Bitcoin.Active && cfg.Bitcoin.RegTest) ||
(cfg.Litecoin.Active && cfg.Litecoin.RegTest) {
conn, err := net.Dial("tcp", bitcoindHost)
if err != nil || conn == nil {
if cfg.Bitcoin.Active && cfg.Bitcoin.RegTest {
rpcPort = 18443
} else if cfg.Litecoin.Active && cfg.Litecoin.RegTest {
rpcPort = 19443
}
bitcoindHost = fmt.Sprintf("%v:%d",
bitcoindMode.RPCHost,
rpcPort)
} else {
conn.Close()
}
}
}
// Establish the connection to bitcoind and create the clients
// required for our relevant subsystems.
bitcoindConn, err := chain.NewBitcoindConn(
activeNetParams.Params, bitcoindHost,
bitcoindMode.RPCUser, bitcoindMode.RPCPass,
bitcoindMode.ZMQPubRawBlock, bitcoindMode.ZMQPubRawTx,
100*time.Millisecond,
)
if err != nil {
return nil, err
}
if err := bitcoindConn.Start(); err != nil {
return nil, fmt.Errorf("unable to connect to bitcoind: "+
"%v", err)
}
cc.chainNotifier = bitcoindnotify.New(
bitcoindConn, activeNetParams.Params, hintCache, hintCache,
)
cc.chainView = chainview.NewBitcoindFilteredChainView(bitcoindConn)
walletConfig.ChainSource = bitcoindConn.NewBitcoindClient()
// If we're not in regtest mode, then we'll attempt to use a
// proper fee estimator for testnet.
rpcConfig := &rpcclient.ConnConfig{
Host: bitcoindHost,
User: bitcoindMode.RPCUser,
Pass: bitcoindMode.RPCPass,
DisableConnectOnNew: true,
DisableAutoReconnect: false,
DisableTLS: true,
HTTPPostMode: true,
}
if cfg.Bitcoin.Active && !cfg.Bitcoin.RegTest {
ltndLog.Infof("Initializing bitcoind backed fee estimator")
// Finally, we'll re-initialize the fee estimator, as
// if we're using bitcoind as a backend, then we can
// use live fee estimates, rather than a statically
// coded value.
fallBackFeeRate := lnwallet.SatPerKVByte(25 * 1000)
cc.feeEstimator, err = lnwallet.NewBitcoindFeeEstimator(
*rpcConfig, fallBackFeeRate.FeePerKWeight(),
)
if err != nil {
return nil, err
}
if err := cc.feeEstimator.Start(); err != nil {
return nil, err
}
} else if cfg.Litecoin.Active && !cfg.Litecoin.RegTest {
ltndLog.Infof("Initializing litecoind backed fee estimator")
// Finally, we'll re-initialize the fee estimator, as
// if we're using litecoind as a backend, then we can
// use live fee estimates, rather than a statically
// coded value.
fallBackFeeRate := lnwallet.SatPerKVByte(25 * 1000)
cc.feeEstimator, err = lnwallet.NewBitcoindFeeEstimator(
*rpcConfig, fallBackFeeRate.FeePerKWeight(),
)
if err != nil {
return nil, err
}
if err := cc.feeEstimator.Start(); err != nil {
return nil, err
}
}
case "btcd", "ltcd":
// Otherwise, we'll be speaking directly via RPC to a node.
//
// So first we'll load btcd/ltcd's TLS cert for the RPC
// connection. If a raw cert was specified in the config, then
// we'll set that directly. Otherwise, we attempt to read the
// cert from the path specified in the config.
var btcdMode *btcdConfig
switch {
case cfg.Bitcoin.Active:
btcdMode = cfg.BtcdMode
case cfg.Litecoin.Active:
btcdMode = cfg.LtcdMode
}
var rpcCert []byte
if btcdMode.RawRPCCert != "" {
rpcCert, err = hex.DecodeString(btcdMode.RawRPCCert)
if err != nil {
return nil, err
}
} else {
certFile, err := os.Open(btcdMode.RPCCert)
if err != nil {
return nil, err
}
rpcCert, err = ioutil.ReadAll(certFile)
if err != nil {
return nil, err
}
if err := certFile.Close(); err != nil {
return nil, err
}
}
// If the specified host for the btcd/ltcd RPC server already
// has a port specified, then we use that directly. Otherwise,
// we assume the default port according to the selected chain
// parameters.
var btcdHost string
if strings.Contains(btcdMode.RPCHost, ":") {
btcdHost = btcdMode.RPCHost
} else {
btcdHost = fmt.Sprintf("%v:%v", btcdMode.RPCHost,
activeNetParams.rpcPort)
}
btcdUser := btcdMode.RPCUser
btcdPass := btcdMode.RPCPass
rpcConfig := &rpcclient.ConnConfig{
Host: btcdHost,
Endpoint: "ws",
User: btcdUser,
Pass: btcdPass,
Certificates: rpcCert,
DisableTLS: false,
DisableConnectOnNew: true,
DisableAutoReconnect: false,
}
cc.chainNotifier, err = btcdnotify.New(
rpcConfig, activeNetParams.Params, hintCache, hintCache,
)
if err != nil {
return nil, err
}
// Finally, we'll create an instance of the default chain view to be
// used within the routing layer.
cc.chainView, err = chainview.NewBtcdFilteredChainView(*rpcConfig)
if err != nil {
srvrLog.Errorf("unable to create chain view: %v", err)
return nil, err
}
// Create a special websockets rpc client for btcd which will be used
// by the wallet for notifications, calls, etc.
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chainRPC, err := chain.NewRPCClient(activeNetParams.Params, btcdHost,
btcdUser, btcdPass, rpcCert, false, 20)
if err != nil {
return nil, err
}
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walletConfig.ChainSource = chainRPC
// If we're not in simnet or regtest mode, then we'll attempt
// to use a proper fee estimator for testnet.
if !cfg.Bitcoin.SimNet && !cfg.Litecoin.SimNet &&
!cfg.Bitcoin.RegTest && !cfg.Litecoin.RegTest {
ltndLog.Infof("Initializing btcd backed fee estimator")
// Finally, we'll re-initialize the fee estimator, as
// if we're using btcd as a backend, then we can use
// live fee estimates, rather than a statically coded
// value.
fallBackFeeRate := lnwallet.SatPerKVByte(25 * 1000)
cc.feeEstimator, err = lnwallet.NewBtcdFeeEstimator(
*rpcConfig, fallBackFeeRate.FeePerKWeight(),
)
if err != nil {
return nil, err
}
if err := cc.feeEstimator.Start(); err != nil {
return nil, err
}
}
default:
return nil, fmt.Errorf("unknown node type: %s",
homeChainConfig.Node)
}
wc, err := btcwallet.New(*walletConfig)
if err != nil {
fmt.Printf("unable to create wallet controller: %v\n", err)
return nil, err
}
cc.msgSigner = wc
cc.signer = wc
cc.chainIO = wc
cc.wc = wc
// Select the default channel constraints for the primary chain.
channelConstraints := defaultBtcChannelConstraints
if registeredChains.PrimaryChain() == litecoinChain {
channelConstraints = defaultLtcChannelConstraints
}
keyRing := keychain.NewBtcWalletKeyRing(
wc.InternalWallet(), activeNetParams.CoinType,
)
cc.keyRing = keyRing
// Create, and start the lnwallet, which handles the core payment
// channel logic, and exposes control via proxy state machines.
walletCfg := lnwallet.Config{
Database: chanDB,
Notifier: cc.chainNotifier,
WalletController: wc,
Signer: cc.signer,
FeeEstimator: cc.feeEstimator,
SecretKeyRing: keyRing,
ChainIO: cc.chainIO,
DefaultConstraints: channelConstraints,
NetParams: *activeNetParams.Params,
}
lnWallet, err := lnwallet.NewLightningWallet(walletCfg)
if err != nil {
fmt.Printf("unable to create wallet: %v\n", err)
return nil, err
}
if err := lnWallet.Startup(); err != nil {
fmt.Printf("unable to start wallet: %v\n", err)
return nil, err
}
ltndLog.Info("LightningWallet opened")
cc.wallet = lnWallet
return cc, nil
}
var (
// bitcoinTestnetGenesis is the genesis hash of Bitcoin's testnet
// chain.
bitcoinTestnetGenesis = chainhash.Hash([chainhash.HashSize]byte{
0x43, 0x49, 0x7f, 0xd7, 0xf8, 0x26, 0x95, 0x71,
0x08, 0xf4, 0xa3, 0x0f, 0xd9, 0xce, 0xc3, 0xae,
0xba, 0x79, 0x97, 0x20, 0x84, 0xe9, 0x0e, 0xad,
0x01, 0xea, 0x33, 0x09, 0x00, 0x00, 0x00, 0x00,
})
// bitcoinMainnetGenesis is the genesis hash of Bitcoin's main chain.
bitcoinMainnetGenesis = chainhash.Hash([chainhash.HashSize]byte{
0x6f, 0xe2, 0x8c, 0x0a, 0xb6, 0xf1, 0xb3, 0x72,
0xc1, 0xa6, 0xa2, 0x46, 0xae, 0x63, 0xf7, 0x4f,
0x93, 0x1e, 0x83, 0x65, 0xe1, 0x5a, 0x08, 0x9c,
0x68, 0xd6, 0x19, 0x00, 0x00, 0x00, 0x00, 0x00,
})
// litecoinTestnetGenesis is the genesis hash of Litecoin's testnet4
// chain.
litecoinTestnetGenesis = chainhash.Hash([chainhash.HashSize]byte{
0xa0, 0x29, 0x3e, 0x4e, 0xeb, 0x3d, 0xa6, 0xe6,
0xf5, 0x6f, 0x81, 0xed, 0x59, 0x5f, 0x57, 0x88,
0x0d, 0x1a, 0x21, 0x56, 0x9e, 0x13, 0xee, 0xfd,
0xd9, 0x51, 0x28, 0x4b, 0x5a, 0x62, 0x66, 0x49,
})
// litecoinMainnetGenesis is the genesis hash of Litecoin's main chain.
litecoinMainnetGenesis = chainhash.Hash([chainhash.HashSize]byte{
0xe2, 0xbf, 0x04, 0x7e, 0x7e, 0x5a, 0x19, 0x1a,
0xa4, 0xef, 0x34, 0xd3, 0x14, 0x97, 0x9d, 0xc9,
0x98, 0x6e, 0x0f, 0x19, 0x25, 0x1e, 0xda, 0xba,
0x59, 0x40, 0xfd, 0x1f, 0xe3, 0x65, 0xa7, 0x12,
})
// chainMap is a simple index that maps a chain's genesis hash to the
// chainCode enum for that chain.
chainMap = map[chainhash.Hash]chainCode{
bitcoinTestnetGenesis: bitcoinChain,
litecoinTestnetGenesis: litecoinChain,
bitcoinMainnetGenesis: bitcoinChain,
litecoinMainnetGenesis: litecoinChain,
}
// chainDNSSeeds is a map of a chain's hash to the set of DNS seeds
// that will be use to bootstrap peers upon first startup.
//
// The first item in the array is the primary host we'll use to attempt
// the SRV lookup we require. If we're unable to receive a response
// over UDP, then we'll fall back to manual TCP resolution. The second
// item in the array is a special A record that we'll query in order to
// receive the IP address of the current authoritative DNS server for
// the network seed.
//
// TODO(roasbeef): extend and collapse these and chainparams.go into
// struct like chaincfg.Params
chainDNSSeeds = map[chainhash.Hash][][2]string{
bitcoinMainnetGenesis: {
{
"nodes.lightning.directory",
"soa.nodes.lightning.directory",
},
},
bitcoinTestnetGenesis: {
{
"test.nodes.lightning.directory",
"soa.nodes.lightning.directory",
},
},
litecoinMainnetGenesis: {
{
"ltc.nodes.lightning.directory",
"soa.nodes.lightning.directory",
},
},
}
)
// chainRegistry keeps track of the current chains
type chainRegistry struct {
sync.RWMutex
activeChains map[chainCode]*chainControl
netParams map[chainCode]*bitcoinNetParams
primaryChain chainCode
}
// newChainRegistry creates a new chainRegistry.
func newChainRegistry() *chainRegistry {
return &chainRegistry{
activeChains: make(map[chainCode]*chainControl),
netParams: make(map[chainCode]*bitcoinNetParams),
}
}
// RegisterChain assigns an active chainControl instance to a target chain
// identified by its chainCode.
func (c *chainRegistry) RegisterChain(newChain chainCode, cc *chainControl) {
c.Lock()
c.activeChains[newChain] = cc
c.Unlock()
}
// LookupChain attempts to lookup an active chainControl instance for the
// target chain.
func (c *chainRegistry) LookupChain(targetChain chainCode) (*chainControl, bool) {
c.RLock()
cc, ok := c.activeChains[targetChain]
c.RUnlock()
return cc, ok
}
// LookupChainByHash attempts to look up an active chainControl which
// corresponds to the passed genesis hash.
func (c *chainRegistry) LookupChainByHash(chainHash chainhash.Hash) (*chainControl, bool) {
c.RLock()
defer c.RUnlock()
targetChain, ok := chainMap[chainHash]
if !ok {
return nil, ok
}
cc, ok := c.activeChains[targetChain]
return cc, ok
}
// RegisterPrimaryChain sets a target chain as the "home chain" for lnd.
func (c *chainRegistry) RegisterPrimaryChain(cc chainCode) {
c.Lock()
defer c.Unlock()
c.primaryChain = cc
}
// PrimaryChain returns the primary chain for this running lnd instance. The
// primary chain is considered the "home base" while the other registered
// chains are treated as secondary chains.
func (c *chainRegistry) PrimaryChain() chainCode {
c.RLock()
defer c.RUnlock()
return c.primaryChain
}
// ActiveChains returns a slice containing the active chains.
func (c *chainRegistry) ActiveChains() []chainCode {
c.RLock()
defer c.RUnlock()
chains := make([]chainCode, 0, len(c.activeChains))
for activeChain := range c.activeChains {
chains = append(chains, activeChain)
}
return chains
}
// NumActiveChains returns the total number of active chains.
func (c *chainRegistry) NumActiveChains() uint32 {
c.RLock()
defer c.RUnlock()
return uint32(len(c.activeChains))
}
// initNeutrinoBackend inits a new instance of the neutrino light client
// backend given a target chain directory to store the chain state.
func initNeutrinoBackend(chainDir string) (*neutrino.ChainService, func(), error) {
// 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,
normalizeNetwork(activeNetParams.Name),
)
// Ensure that the neutrino db path exists.
if err := os.MkdirAll(dbPath, 0700); err != nil {
return nil, nil, err
}
dbName := filepath.Join(dbPath, "neutrino.db")
db, err := walletdb.Create("bdb", dbName)
if err != nil {
return nil, nil, fmt.Errorf("unable to create neutrino "+
"database: %v", 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: *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())
},
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
},
}
neutrino.MaxPeers = 8
neutrino.BanDuration = time.Hour * 48
neutrinoCS, err := neutrino.NewChainService(config)
if err != nil {
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() {
neutrinoCS.Stop()
db.Close()
}
return neutrinoCS, cleanUp, nil
}