ethereum, Node Initialization

Node

Node is the place where everthing starts.

// Node is a container on which services can be registered.
type Node struct {
	eventmux *event.TypeMux // Event multiplexer used between the services of a stack
	config   *Config
	accman   *accounts.Manager

	ephemeralKeystore string            // if non-empty, the key directory that will be removed by Stop
	instanceDirLock   fileutil.Releaser // prevents concurrent use of instance directory

	serverConfig p2p.Config
	server       *p2p.Server // Currently running P2P networking layer

	serviceFuncs []ServiceConstructor     // Service constructors (in dependency order)
	services     map[reflect.Type]Service // Currently running services

	rpcAPIs       []rpc.API   // List of APIs currently provided by the node
	inprocHandler *rpc.Server // In-process RPC request handler to process the API requests

	ipcEndpoint string       // IPC endpoint to listen at (empty = IPC disabled)
	ipcListener net.Listener // IPC RPC listener socket to serve API requests
	ipcHandler  *rpc.Server  // IPC RPC request handler to process the API requests

	httpEndpoint  string       // HTTP endpoint (interface + port) to listen at (empty = HTTP disabled)
	httpWhitelist []string     // HTTP RPC modules to allow through this endpoint
	httpListener  net.Listener // HTTP RPC listener socket to server API requests
	httpHandler   *rpc.Server  // HTTP RPC request handler to process the API requests

	wsEndpoint string       // Websocket endpoint (interface + port) to listen at (empty = websocket disabled)
	wsListener net.Listener // Websocket RPC listener socket to server API requests
	wsHandler  *rpc.Server  // Websocket RPC request handler to process the API requests

	stop chan struct{} // Channel to wait for termination notifications
	lock sync.RWMutex

	log log.Logger
}

AccountManager

// Manager is an overarching account manager that can communicate with various
// backends for signing transactions.
type Manager struct {
	config   *Config                    // Global account manager configurations
	backends map[reflect.Type][]Backend // Index of backends currently registered
	updaters []event.Subscription       // Wallet update subscriptions for all backends
	updates  chan WalletEvent           // Subscription sink for backend wallet changes
	wallets  []Wallet                   // Cache of all wallets from all registered backends

	feed event.Feed // Wallet feed notifying of arrivals/departures

	quit chan chan error
	lock sync.RWMutex
}


// NewManager creates a generic account manager to sign transaction via various
// supported backends.
func NewManager(config *Config, backends ...Backend) *Manager {
	// Retrieve the initial list of wallets from the backends and sort by URL
	var wallets []Wallet
	for _, backend := range backends {
		wallets = merge(wallets, backend.Wallets()...)
	}
	// Subscribe to wallet notifications from all backends
	updates := make(chan WalletEvent, 4*len(backends))

	subs := make([]event.Subscription, len(backends))
	for i, backend := range backends {
		subs[i] = backend.Subscribe(updates)
	}
	// Assemble the account manager and return
	am := &Manager{
		config:   config,
		backends: make(map[reflect.Type][]Backend),
		updaters: subs,
		updates:  updates,
		wallets:  wallets,
		quit:     make(chan chan error),
	}
	for _, backend := range backends {
		kind := reflect.TypeOf(backend)
		am.backends[kind] = append(am.backends[kind], backend)
	}
	go am.update()

	return am
}

// update is the wallet event loop listening for notifications from the backends
// and updating the cache of wallets.
func (am *Manager) update() {
	// Close all subscriptions when the manager terminates
	defer func() {
		am.lock.Lock()
		for _, sub := range am.updaters {
			sub.Unsubscribe()
		}
		am.updaters = nil
		am.lock.Unlock()
	}()

	// Loop until termination
	for {
		select {
		case event := <-am.updates:
			// Wallet event arrived, update local cache
			am.lock.Lock()
			switch event.Kind {
			case WalletArrived:
				am.wallets = merge(am.wallets, event.Wallet)
			case WalletDropped:
				am.wallets = drop(am.wallets, event.Wallet)
			}
			am.lock.Unlock()

			// Notify any listeners of the event
			am.feed.Send(event)

		case errc := <-am.quit:
			// Manager terminating, return
			errc <- nil
			return
		}
	}
}

// events
const (
	// WalletArrived is fired when a new wallet is detected either via USB or via
	// a filesystem event in the keystore.
	WalletArrived WalletEventType = iota

	// WalletOpened is fired when a wallet is successfully opened with the purpose
	// of starting any background processes such as automatic key derivation.
	WalletOpened

	// WalletDropped
	WalletDropped
)

Account Mgr starts a goroutine ‘am.update()’ to receive update notification from any wallets. Each backend will subscribe to the update channel:

subs[i] = backend.Subscribe(updates)

Then the event will be fed to all listeners.

am.feed.Send(event)

Initialization

func makeFullNode(ctx *cli.Context) *node.Node {
	stack, cfg := makeConfigNode(ctx)
	if ctx.GlobalIsSet(utils.OverrideIstanbulFlag.Name) {
		cfg.Eth.OverrideIstanbul = new(big.Int).SetUint64(ctx.GlobalUint64(utils.OverrideIstanbulFlag.Name))
	}
	if ctx.GlobalIsSet(utils.OverrideMuirGlacierFlag.Name) {
		cfg.Eth.OverrideMuirGlacier = new(big.Int).SetUint64(ctx.GlobalUint64(utils.OverrideMuirGlacierFlag.Name))
	}
	utils.RegisterEthService(stack, &cfg.Eth)

	// Whisper must be explicitly enabled by specifying at least 1 whisper flag or in dev mode
	shhEnabled := enableWhisper(ctx)
	shhAutoEnabled := !ctx.GlobalIsSet(utils.WhisperEnabledFlag.Name) && ctx.GlobalIsSet(utils.DeveloperFlag.Name)
	if shhEnabled || shhAutoEnabled {
		if ctx.GlobalIsSet(utils.WhisperMaxMessageSizeFlag.Name) {
			cfg.Shh.MaxMessageSize = uint32(ctx.Int(utils.WhisperMaxMessageSizeFlag.Name))
		}
		if ctx.GlobalIsSet(utils.WhisperMinPOWFlag.Name) {
			cfg.Shh.MinimumAcceptedPOW = ctx.Float64(utils.WhisperMinPOWFlag.Name)
		}
		if ctx.GlobalIsSet(utils.WhisperRestrictConnectionBetweenLightClientsFlag.Name) {
			cfg.Shh.RestrictConnectionBetweenLightClients = true
		}
		utils.RegisterShhService(stack, &cfg.Shh)
	}
	// Configure GraphQL if requested
	if ctx.GlobalIsSet(utils.GraphQLEnabledFlag.Name) {
		utils.RegisterGraphQLService(stack, cfg.Node.GraphQLEndpoint(), cfg.Node.GraphQLCors, cfg.Node.GraphQLVirtualHosts, cfg.Node.HTTPTimeouts)
	}
	// Add the Ethereum Stats daemon if requested.
	if cfg.Ethstats.URL != "" {
		utils.RegisterEthStatsService(stack, cfg.Ethstats.URL)
	}
	return stack
}

Flow

• makeFullNode
  • makeConfigNode
    • loadConfig, loading config file
    • SetNodeConfig
    • Node.New
      • makeAccountManager
  • RegisterEthService, add ethereum client to the stack. Light or Full
  • RegisterShhService, if Whisper enabled
  • RegisterGraphQLService, if GraphQL requested
  • RegisterEthStatsService, if stats daemon enabled
• startNode
  • Add debug Memsize
  • StartNode
    • Start all registered services
      • call constructor and save it, Make Ethereum or Light Ethereum object
      • Start P2P server
      • Start service
    • startRPC
      • startInProc
      • startIPC
      • startHTTP
      • startWS
    • signal.Notify(sigc, syscall.SIGINT, syscall.SIGTERM)
  • unlockAccounts
  • stack.Attach(), make a RPC client attached to Node
  • goroutine : Listen for wallet event till termination
  • goroutine : status synchronization monitoring
  • StartMining

Ethereum Object

The call stack of Ethereum object initialization:

github.com/ethereum/go-ethereum/eth.New at backend.go:119
github.com/ethereum/go-ethereum/cmd/utils.RegisterEthService.func2 at flags.go:1564
github.com/ethereum/go-ethereum/node.(*Node).Start at node.go:206
github.com/ethereum/go-ethereum/cmd/utils.StartNode at cmd.go:67
main.startNode at main.go:327
main.geth at main.go:308
gopkg.in/urfave/cli%2ev1.HandleAction at app.go:490
gopkg.in/urfave/cli%2ev1.(*App).Run at app.go:264
main.main at main.go:248
runtime.main at proc.go:203
runtime.goexit at asm_amd64.s:1357
 - Async stack trace
runtime.rt0_go at asm_amd64.s:220

// New creates a new Ethereum object (including the
// initialisation of the common Ethereum object)
func New(ctx *node.ServiceContext, config *Config) (*Ethereum, error) {
	// Ensure configuration values are compatible and sane
	if config.SyncMode == downloader.LightSync {
		return nil, errors.New("can't run eth.Ethereum in light sync mode, use les.LightEthereum")
	}
	if !config.SyncMode.IsValid() {
		return nil, fmt.Errorf("invalid sync mode %d", config.SyncMode)
	}
	if config.Miner.GasPrice == nil || config.Miner.GasPrice.Cmp(common.Big0) <= 0 {
		log.Warn("Sanitizing invalid miner gas price", "provided", config.Miner.GasPrice, "updated", DefaultConfig.Miner.GasPrice)
		config.Miner.GasPrice = new(big.Int).Set(DefaultConfig.Miner.GasPrice)
	}
	if config.NoPruning && config.TrieDirtyCache > 0 {
		config.TrieCleanCache += config.TrieDirtyCache
		config.TrieDirtyCache = 0
	}
	log.Info("Allocated trie memory caches", "clean", common.StorageSize(config.TrieCleanCache)*1024*1024, "dirty", common.StorageSize(config.TrieDirtyCache)*1024*1024)

	// Assemble the Ethereum object
	chainDb, err := ctx.OpenDatabaseWithFreezer("chaindata", config.DatabaseCache, config.DatabaseHandles, config.DatabaseFreezer, "eth/db/chaindata/")
	if err != nil {
		return nil, err
	}
	chainConfig, genesisHash, genesisErr := core.SetupGenesisBlockWithOverride(chainDb, config.Genesis, config.OverrideIstanbul, config.OverrideMuirGlacier)
	if _, ok := genesisErr.(*params.ConfigCompatError); genesisErr != nil && !ok {
		return nil, genesisErr
	}
	log.Info("Initialised chain configuration", "config", chainConfig)

	eth := &Ethereum{
		config:         config,
		chainDb:        chainDb,
		eventMux:       ctx.EventMux,
		accountManager: ctx.AccountManager,
		engine:         CreateConsensusEngine(ctx, chainConfig, &config.Ethash, config.Miner.Notify, config.Miner.Noverify, chainDb),
		shutdownChan:   make(chan bool),
		networkID:      config.NetworkId,
		gasPrice:       config.Miner.GasPrice,
		etherbase:      config.Miner.Etherbase,
		bloomRequests:  make(chan chan *bloombits.Retrieval),
		bloomIndexer:   NewBloomIndexer(chainDb, params.BloomBitsBlocks, params.BloomConfirms),
	}

	bcVersion := rawdb.ReadDatabaseVersion(chainDb)
	var dbVer = "<nil>"
	if bcVersion != nil {
		dbVer = fmt.Sprintf("%d", *bcVersion)
	}
	log.Info("Initialising Ethereum protocol", "versions", ProtocolVersions, "network", config.NetworkId, "dbversion", dbVer)

	if !config.SkipBcVersionCheck {
		if bcVersion != nil && *bcVersion > core.BlockChainVersion {
			return nil, fmt.Errorf("database version is v%d, Geth %s only supports v%d", *bcVersion, params.VersionWithMeta, core.BlockChainVersion)
		} else if bcVersion == nil || *bcVersion < core.BlockChainVersion {
			log.Warn("Upgrade blockchain database version", "from", dbVer, "to", core.BlockChainVersion)
			rawdb.WriteDatabaseVersion(chainDb, core.BlockChainVersion)
		}
	}
	var (
		vmConfig = vm.Config{
			EnablePreimageRecording: config.EnablePreimageRecording,
			EWASMInterpreter:        config.EWASMInterpreter,
			EVMInterpreter:          config.EVMInterpreter,
		}
		cacheConfig = &core.CacheConfig{
			TrieCleanLimit:      config.TrieCleanCache,
			TrieCleanNoPrefetch: config.NoPrefetch,
			TrieDirtyLimit:      config.TrieDirtyCache,
			TrieDirtyDisabled:   config.NoPruning,
			TrieTimeLimit:       config.TrieTimeout,
		}
	)
	eth.blockchain, err = core.NewBlockChain(chainDb, cacheConfig, chainConfig, eth.engine, vmConfig, eth.shouldPreserve)
	if err != nil {
		return nil, err
	}
	// Rewind the chain in case of an incompatible config upgrade.
	if compat, ok := genesisErr.(*params.ConfigCompatError); ok {
		log.Warn("Rewinding chain to upgrade configuration", "err", compat)
		eth.blockchain.SetHead(compat.RewindTo)
		rawdb.WriteChainConfig(chainDb, genesisHash, chainConfig)
	}
	eth.bloomIndexer.Start(eth.blockchain)

	if config.TxPool.Journal != "" {
		config.TxPool.Journal = ctx.ResolvePath(config.TxPool.Journal)
	}
	eth.txPool = core.NewTxPool(config.TxPool, chainConfig, eth.blockchain)

	// Permit the downloader to use the trie cache allowance during fast sync
	cacheLimit := cacheConfig.TrieCleanLimit + cacheConfig.TrieDirtyLimit
	checkpoint := config.Checkpoint
	if checkpoint == nil {
		checkpoint = params.TrustedCheckpoints[genesisHash]
	}
	if eth.protocolManager, err = NewProtocolManager(chainConfig, checkpoint, config.SyncMode, config.NetworkId, eth.eventMux, eth.txPool, eth.engine, eth.blockchain, chainDb, cacheLimit, config.Whitelist); err != nil {
		return nil, err
	}
	eth.miner = miner.New(eth, &config.Miner, chainConfig, eth.EventMux(), eth.engine, eth.isLocalBlock)
	eth.miner.SetExtra(makeExtraData(config.Miner.ExtraData))

	eth.APIBackend = &EthAPIBackend{ctx.ExtRPCEnabled(), eth, nil}
	gpoParams := config.GPO
	if gpoParams.Default == nil {
		gpoParams.Default = config.Miner.GasPrice
	}
	eth.APIBackend.gpo = gasprice.NewOracle(eth.APIBackend, gpoParams)

	eth.dialCandiates, err = eth.setupDiscovery(&ctx.Config.P2P)
	if err != nil {
		return nil, err
	}

	return eth, nil
}

• Set Gas Price
• OpenDatabaseWithFreezer, chaindata
• SetupGenesisBlockWithOverride
• CreateConsensusEngine
• NewBloomIndexer
• NewBlockChain
  • NewDatabaseWithCache, stateCache
  • NewBlockValidator
  • newStatePrefetcher
  • NewStateProcessor
  • NewHeaderChain
  • loadLastState, loads the last known chain state from the database
  • Check block data…
  • goroutine, procFutureBlocks() periodically
• eth.bloomIndexer.Start(eth.blockchain), goroutine to feed chain head events into the indexer
• NewTxPool
• NewProtocolManager
  • trie.NewSyncBloom， if fast sync
  • downloader.New
  • fetcher.NewBlockFetcher
  • fetcher.NewTxFetcher
• miner.New
  • start miner workers
  • goroutine, keeps track of the downloader events
• make APIBackend
• eth.setupDiscovery, creates the node discovery source for the eth protocol

Ethereum Start Service

Start Service will start Ethereum.

// Start implements node.Service, starting all internal goroutines needed by the
// Ethereum protocol implementation.
func (s *Ethereum) Start(srvr *p2p.Server) error {
	s.startEthEntryUpdate(srvr.LocalNode())

	// Start the bloom bits servicing goroutines
	s.startBloomHandlers(params.BloomBitsBlocks)

	// Start the RPC service
	s.netRPCService = ethapi.NewPublicNetAPI(srvr, s.NetVersion())

	// Figure out a max peers count based on the server limits
	maxPeers := srvr.MaxPeers
	if s.config.LightServ > 0 {
		if s.config.LightPeers >= srvr.MaxPeers {
			return fmt.Errorf("invalid peer config: light peer count (%d) >= total peer count (%d)", s.config.LightPeers, srvr.MaxPeers)
		}
		maxPeers -= s.config.LightPeers
	}
	// Start the networking layer and the light server if requested
	s.protocolManager.Start(maxPeers)
	if s.lesServer != nil {
		s.lesServer.Start(srvr)
	}
	return nil
}

• startEthEntryUpdate, starts the ENR updater loop goroutine, waiting for chainhead event
• startBloomHandlers, starts a batch(16 by default) of goroutines to accept bloom bit database retrievals from possibly a range of filters and serving the data to satisfy.
• NewPublicNetAPI, RPC API
• s.protocolManager.Start(maxPeers)

func (pm *ProtocolManager) Start(maxPeers int) {
	pm.maxPeers = maxPeers

	// broadcast transactions
	pm.txsCh = make(chan core.NewTxsEvent, txChanSize)
	pm.txsSub = pm.txpool.SubscribeNewTxsEvent(pm.txsCh)
	go pm.txBroadcastLoop()

	// broadcast mined blocks
	pm.minedBlockSub = pm.eventMux.Subscribe(core.NewMinedBlockEvent{})
	go pm.minedBroadcastLoop()

	// start sync handlers
	go pm.syncer()
	go pm.txsyncLoop64() // TODO(karalabe): Legacy initial tx echange, drop with eth/64.
}

Protocol Manager

Ethereum sub protocol manager. can manage peers capable with the Ethereum network.

func (pm *ProtocolManager) Start(maxPeers int) {
	pm.maxPeers = maxPeers

	// broadcast transactions
	pm.txsCh = make(chan core.NewTxsEvent, txChanSize)
	pm.txsSub = pm.txpool.SubscribeNewTxsEvent(pm.txsCh)
	go pm.txBroadcastLoop()

	// broadcast mined blocks
	pm.minedBlockSub = pm.eventMux.Subscribe(core.NewMinedBlockEvent{})
	go pm.minedBroadcastLoop()

	// start sync handlers
	go pm.syncer()
	go pm.txsyncLoop64() // TODO(karalabe): Legacy initial tx echange, drop with eth/64.
}

P2P server

Setup local node

• Prepare data
• Open DB
• NewLocalNode. The node ID will be calculated with Pubkey.
• NAT discovery UPnP and PMP, by default. In a goroutine.
• SetStaticIP(ip)

Setup Listening

Start a goroutine looping for accepting inbound connections. Start a background gorouting for updating NAT map.

This gorouting uses go chan to implement a limiter of max allowed connections. defaultMaxPendingPeers = 50 or --maxpendpeers value

Any inbound connection will be handled by:

// SetupConn runs the handshakes and attempts to add the connection
// as a peer. It returns when the connection has been added as a peer
// or the handshakes have failed.
func (srv *Server) SetupConn(fd net.Conn, flags connFlag, dialDest *enode.Node) error {
	c := &conn{fd: fd, transport: srv.newTransport(fd), flags: flags, cont: make(chan error)}
	err := srv.setupConn(c, flags, dialDest)
	if err != nil {
		c.close(err)
	}
	return err
}

As a result, any valid connection will be accepted as a peer, by sending a message to srv.checkpointAddPeer.

Setup discovery

• Setup UDP listener
• Create NAT mapping if need
• Listen UDP, goroutines
  • table loop, KAD table refresh
  • loop, handle refresh timer and the pending reply queue
  • readloop, handle UDP packets
• discv5.ListenUDP, v5 discovery if configured
• setupDialScheduler
• Run()

KAD discovery

func ListenV4(c UDPConn, ln *enode.LocalNode, cfg Config) (*UDPv4, error) {
	closeCtx, cancel := context.WithCancel(context.Background())
	t := &UDPv4{
		conn:            c,
		priv:            cfg.PrivateKey,
		netrestrict:     cfg.NetRestrict,
		localNode:       ln,
		db:              ln.Database(),
		gotreply:        make(chan reply),
		addReplyMatcher: make(chan *replyMatcher),
		closeCtx:        closeCtx,
		cancelCloseCtx:  cancel,
		log:             cfg.Log,
	}
	if t.log == nil {
		t.log = log.Root()
	}

	tab, err := newTable(t, ln.Database(), cfg.Bootnodes, t.log)
	if err != nil {
		return nil, err
	}
	t.tab = tab
	go tab.loop()

	t.wg.Add(2)
	go t.loop()
	go t.readLoop(cfg.Unhandled)
	return t, nil
}

v5 discovery

It is loosely inspired by the Kademlia DHT, but unlike most DHTs no arbitrary keys and values are stored. Instead, the DHT stores and relays ‘node records’, which are signed documents providing information about nodes in the network. Node Discovery acts as a database of all live nodes in the network and performs three basic functions:

• Sampling the set of all live participants: by walking the DHT, the network can be enumerated.
• Searching for participants providing a certain service: Node Discovery v5 includes a scalable facility for registering ‘topic advertisements’. These advertisements can be queried and nodes advertising a topic found.
• Authoritative resolution of node records: if a node’s ID is known, the most recent version of its record can be retrieved.

Some points

• Mainnet geneisi will be used if no genesisi specified when running geth
• $datadir/geth/nodekey will be created if not existed at the first running
• Node.Name is hardcoded to ‘Geth’ + version + runtime: Geth/v1.9.13-unstable/windows-amd64/go1.13.5
• Node.ID is set to PubkeyToIDV4(&key.PublicKey), in NewLocalNode