Merge pull request #1351 from karalabe/eth61

Implement eth/61

cmd/geth/main.go

@@ -277,7 +277,6 @@ JavaScript API. See https://github.com/ethereum/go-ethereum/wiki/Javascipt-Conso
 		utils.ExecFlag,
 		utils.WhisperEnabledFlag,
 		utils.VMDebugFlag,
-		utils.ProtocolVersionFlag,
 		utils.NetworkIdFlag,
 		utils.RPCCORSDomainFlag,
 		utils.VerbosityFlag,
@@ -644,7 +643,7 @@ func version(c *cli.Context) {
 	if gitCommit != "" {
 		fmt.Println("Git Commit:", gitCommit)
 	}
-	fmt.Println("Protocol Version:", c.GlobalInt(utils.ProtocolVersionFlag.Name))
+	fmt.Println("Protocol Versions:", eth.ProtocolVersions)
 	fmt.Println("Network Id:", c.GlobalInt(utils.NetworkIdFlag.Name))
 	fmt.Println("Go Version:", runtime.Version())
 	fmt.Println("OS:", runtime.GOOS)

cmd/utils/flags.go

@@ -82,11 +82,6 @@ var (
 		Usage: "Data directory to be used",
 		Value: DirectoryString{common.DefaultDataDir()},
 	}
-	ProtocolVersionFlag = cli.IntFlag{
-		Name:  "protocolversion",
-		Usage: "ETH protocol version (integer)",
-		Value: eth.ProtocolVersion,
-	}
 	NetworkIdFlag = cli.IntFlag{
 		Name:  "networkid",
 		Usage: "Network Id (integer)",
@@ -359,7 +354,6 @@ func MakeEthConfig(clientID, version string, ctx *cli.Context) *eth.Config {
 	return &eth.Config{
 		Name:                    common.MakeName(clientID, version),
 		DataDir:                 ctx.GlobalString(DataDirFlag.Name),
-		ProtocolVersion:         ctx.GlobalInt(ProtocolVersionFlag.Name),
 		GenesisNonce:            ctx.GlobalInt(GenesisNonceFlag.Name),
 		BlockChainVersion:       ctx.GlobalInt(BlockchainVersionFlag.Name),
 		SkipBcVersionCheck:      false,

eth/backend.go

@@ -11,8 +11,6 @@ import (
 	"strings"
 	"time"
 
-	"github.com/ethereum/go-ethereum/metrics"
-
 	"github.com/ethereum/ethash"
 	"github.com/ethereum/go-ethereum/accounts"
 	"github.com/ethereum/go-ethereum/common"
@@ -26,6 +24,7 @@ import (
 	"github.com/ethereum/go-ethereum/event"
 	"github.com/ethereum/go-ethereum/logger"
 	"github.com/ethereum/go-ethereum/logger/glog"
+	"github.com/ethereum/go-ethereum/metrics"
 	"github.com/ethereum/go-ethereum/miner"
 	"github.com/ethereum/go-ethereum/p2p"
 	"github.com/ethereum/go-ethereum/p2p/discover"
@@ -58,7 +57,6 @@ var (
 
 type Config struct {
 	Name         string
-	ProtocolVersion int
 	NetworkId    int
 	GenesisNonce int
 
@@ -226,7 +224,6 @@ type Ethereum struct {
 	autodagquit   chan bool
 	etherbase     common.Address
 	clientVersion string
-	ethVersionId  int
 	netVersionId  int
 	shhVersionId  int
 }
@@ -291,6 +288,11 @@ func New(config *Config) (*Ethereum, error) {
 	nodeDb := filepath.Join(config.DataDir, "nodes")
 
 	// Perform database sanity checks
+	/*
+		// The databases were previously tied to protocol versions. Currently we
+		// are moving away from this decision as approaching Frontier. The below
+		// check was left in for now but should eventually be just dropped.
+
 		d, _ := blockDb.Get([]byte("ProtocolVersion"))
 		protov := int(common.NewValue(d).Uint())
 		if protov != config.ProtocolVersion && protov != 0 {
@@ -298,7 +300,8 @@ func New(config *Config) (*Ethereum, error) {
 			return nil, fmt.Errorf("Database version mismatch. Protocol(%d / %d). `rm -rf %s`", protov, config.ProtocolVersion, path)
 		}
 		saveProtocolVersion(blockDb, config.ProtocolVersion)
-	glog.V(logger.Info).Infof("Protocol Version: %v, Network Id: %v", config.ProtocolVersion, config.NetworkId)
+	*/
+	glog.V(logger.Info).Infof("Protocol Versions: %v, Network Id: %v", ProtocolVersions, config.NetworkId)
 
 	if !config.SkipBcVersionCheck {
 		b, _ := blockDb.Get([]byte("BlockchainVersion"))
@@ -321,7 +324,6 @@ func New(config *Config) (*Ethereum, error) {
 		DataDir:                 config.DataDir,
 		etherbase:               common.HexToAddress(config.Etherbase),
 		clientVersion:           config.Name, // TODO should separate from Name
-		ethVersionId:            config.ProtocolVersion,
 		netVersionId:            config.NetworkId,
 		NatSpec:                 config.NatSpec,
 		MinerThreads:            config.MinerThreads,
@@ -345,7 +347,7 @@ func New(config *Config) (*Ethereum, error) {
 
 	eth.blockProcessor = core.NewBlockProcessor(stateDb, extraDb, eth.pow, eth.chainManager, eth.EventMux())
 	eth.chainManager.SetProcessor(eth.blockProcessor)
-	eth.protocolManager = NewProtocolManager(config.ProtocolVersion, config.NetworkId, eth.eventMux, eth.txPool, eth.pow, eth.chainManager)
+	eth.protocolManager = NewProtocolManager(config.NetworkId, eth.eventMux, eth.txPool, eth.pow, eth.chainManager)
 
 	eth.miner = miner.New(eth, eth.EventMux(), eth.pow)
 	eth.miner.SetGasPrice(config.GasPrice)
@@ -358,7 +360,7 @@ func New(config *Config) (*Ethereum, error) {
 	if err != nil {
 		return nil, err
 	}
-	protocols := []p2p.Protocol{eth.protocolManager.SubProtocol}
+	protocols := append([]p2p.Protocol{}, eth.protocolManager.SubProtocols...)
 	if config.Shh {
 		protocols = append(protocols, eth.whisper.Protocol())
 	}
@@ -495,7 +497,7 @@ func (s *Ethereum) PeerCount() int                       { return s.net.PeerCoun
 func (s *Ethereum) Peers() []*p2p.Peer                   { return s.net.Peers() }
 func (s *Ethereum) MaxPeers() int                        { return s.net.MaxPeers }
 func (s *Ethereum) ClientVersion() string                { return s.clientVersion }
-func (s *Ethereum) EthVersion() int                      { return s.ethVersionId }
+func (s *Ethereum) EthVersion() int                      { return int(s.protocolManager.SubProtocols[0].Version) }
 func (s *Ethereum) NetVersion() int                      { return s.netVersionId }
 func (s *Ethereum) ShhVersion() int                      { return s.shhVersionId }
 func (s *Ethereum) Downloader() *downloader.Downloader   { return s.protocolManager.downloader }
@@ -504,7 +506,7 @@ func (s *Ethereum) Downloader() *downloader.Downloader   { return s.protocolMana
 func (s *Ethereum) Start() error {
 	jsonlogger.LogJson(&logger.LogStarting{
 		ClientString:    s.net.Name,
-		ProtocolVersion: ProtocolVersion,
+		ProtocolVersion: s.EthVersion(),
 	})
 	err := s.net.Start()
 	if err != nil {
@@ -560,7 +562,7 @@ done:
 func (s *Ethereum) StartForTest() {
 	jsonlogger.LogJson(&logger.LogStarting{
 		ClientString:    s.net.Name,
-		ProtocolVersion: ProtocolVersion,
+		ProtocolVersion: s.EthVersion(),
 	})
 }
 
@@ -667,14 +669,20 @@ func (self *Ethereum) StopAutoDAG() {
 	glog.V(logger.Info).Infof("Automatic pregeneration of ethash DAG OFF (ethash dir: %s)", ethash.DefaultDir)
 }
 
-func saveProtocolVersion(db common.Database, protov int) {
+/*
+	// The databases were previously tied to protocol versions. Currently we
+	// are moving away from this decision as approaching Frontier. The below
+	// code was left in for now but should eventually be just dropped.
+
+	func saveProtocolVersion(db common.Database, protov int) {
 		d, _ := db.Get([]byte("ProtocolVersion"))
 		protocolVersion := common.NewValue(d).Uint()
 
 		if protocolVersion == 0 {
 			db.Put([]byte("ProtocolVersion"), common.NewValue(protov).Bytes())
 		}
-}
+	}
+*/
 
 func saveBlockchainVersion(db common.Database, bcVersion int) {
 	d, _ := db.Get([]byte("BlockchainVersion"))

eth/downloader/peer.go

@@ -15,7 +15,8 @@ import (
 	"gopkg.in/fatih/set.v0"
 )
 
-type hashFetcherFn func(common.Hash) error
+type relativeHashFetcherFn func(common.Hash) error
+type absoluteHashFetcherFn func(uint64, int) error
 type blockFetcherFn func([]common.Hash) error
 
 var (
@@ -37,20 +38,25 @@ type peer struct {
 
 	ignored *set.Set // Set of hashes not to request (didn't have previously)
 
-	getHashes hashFetcherFn  // Method to retrieve a batch of hashes (mockable for testing)
-	getBlocks blockFetcherFn // Method to retrieve a batch of blocks (mockable for testing)
+	getRelHashes relativeHashFetcherFn // Method to retrieve a batch of hashes from an origin hash
+	getAbsHashes absoluteHashFetcherFn // Method to retrieve a batch of hashes from an absolute position
+	getBlocks    blockFetcherFn        // Method to retrieve a batch of blocks
+
+	version int // Eth protocol version number to switch strategies
 }
 
 // newPeer create a new downloader peer, with specific hash and block retrieval
 // mechanisms.
-func newPeer(id string, head common.Hash, getHashes hashFetcherFn, getBlocks blockFetcherFn) *peer {
+func newPeer(id string, version int, head common.Hash, getRelHashes relativeHashFetcherFn, getAbsHashes absoluteHashFetcherFn, getBlocks blockFetcherFn) *peer {
 	return &peer{
 		id:           id,
 		head:         head,
 		capacity:     1,
-		getHashes: getHashes,
+		getRelHashes: getRelHashes,
+		getAbsHashes: getAbsHashes,
 		getBlocks:    getBlocks,
 		ignored:      set.New(),
+		version:      version,
 	}
 }
 

eth/downloader/queue.go

@@ -40,9 +40,9 @@ type queue struct {
 
 	pendPool map[string]*fetchRequest // Currently pending block retrieval operations
 
-	blockPool   map[common.Hash]int // Hash-set of the downloaded data blocks, mapping to cache indexes
+	blockPool   map[common.Hash]uint64 // Hash-set of the downloaded data blocks, mapping to cache indexes
 	blockCache  []*Block               // Downloaded but not yet delivered blocks
-	blockOffset int                 // Offset of the first cached block in the block-chain
+	blockOffset uint64                 // Offset of the first cached block in the block-chain
 
 	lock sync.RWMutex
 }
@@ -53,7 +53,7 @@ func newQueue() *queue {
 		hashPool:   make(map[common.Hash]int),
 		hashQueue:  prque.New(),
 		pendPool:   make(map[string]*fetchRequest),
-		blockPool:  make(map[common.Hash]int),
+		blockPool:  make(map[common.Hash]uint64),
 		blockCache: make([]*Block, blockCacheLimit),
 	}
 }
@@ -69,7 +69,7 @@ func (q *queue) Reset() {
 
 	q.pendPool = make(map[string]*fetchRequest)
 
-	q.blockPool = make(map[common.Hash]int)
+	q.blockPool = make(map[common.Hash]uint64)
 	q.blockOffset = 0
 	q.blockCache = make([]*Block, blockCacheLimit)
 }
@@ -130,7 +130,7 @@ func (q *queue) Has(hash common.Hash) bool {
 
 // Insert adds a set of hashes for the download queue for scheduling, returning
 // the new hashes encountered.
-func (q *queue) Insert(hashes []common.Hash) []common.Hash {
+func (q *queue) Insert(hashes []common.Hash, fifo bool) []common.Hash {
 	q.lock.Lock()
 	defer q.lock.Unlock()
 
@@ -147,8 +147,12 @@ func (q *queue) Insert(hashes []common.Hash) []common.Hash {
 		inserts = append(inserts, hash)
 
 		q.hashPool[hash] = q.hashCounter
+		if fifo {
+			q.hashQueue.Push(hash, -float32(q.hashCounter)) // Lowest gets schedules first
+		} else {
 			q.hashQueue.Push(hash, float32(q.hashCounter)) // Highest gets schedules first
 		}
+	}
 	return inserts
 }
 
@@ -175,7 +179,7 @@ func (q *queue) GetBlock(hash common.Hash) *Block {
 		return nil
 	}
 	// Return the block if it's still available in the cache
-	if q.blockOffset <= index && index < q.blockOffset+len(q.blockCache) {
+	if q.blockOffset <= index && index < q.blockOffset+uint64(len(q.blockCache)) {
 		return q.blockCache[index-q.blockOffset]
 	}
 	return nil
@@ -202,7 +206,7 @@ func (q *queue) TakeBlocks() []*Block {
 	for k, n := len(q.blockCache)-len(blocks), len(q.blockCache); k < n; k++ {
 		q.blockCache[k] = nil
 	}
-	q.blockOffset += len(blocks)
+	q.blockOffset += uint64(len(blocks))
 
 	return blocks
 }
@@ -318,7 +322,7 @@ func (q *queue) Deliver(id string, blocks []*types.Block) (err error) {
 			continue
 		}
 		// If a requested block falls out of the range, the hash chain is invalid
-		index := int(block.NumberU64()) - q.blockOffset
+		index := int(int64(block.NumberU64()) - int64(q.blockOffset))
 		if index >= len(q.blockCache) || index < 0 {
 			return errInvalidChain
 		}
@@ -329,7 +333,7 @@ func (q *queue) Deliver(id string, blocks []*types.Block) (err error) {
 		}
 		delete(request.Hashes, hash)
 		delete(q.hashPool, hash)
-		q.blockPool[hash] = int(block.NumberU64())
+		q.blockPool[hash] = block.NumberU64()
 	}
 	// Return all failed or missing fetches to the queue
 	for hash, index := range request.Hashes {
@@ -346,7 +350,7 @@ func (q *queue) Deliver(id string, blocks []*types.Block) (err error) {
 }
 
 // Prepare configures the block cache offset to allow accepting inbound blocks.
-func (q *queue) Prepare(offset int) {
+func (q *queue) Prepare(offset uint64) {
 	q.lock.Lock()
 	defer q.lock.Unlock()
 

eth/metrics.go

+package eth
+
+import (
+	"github.com/ethereum/go-ethereum/metrics"
+)
+
+var (
+	propTxnInPacketsMeter    = metrics.NewMeter("eth/prop/txns/in/packets")
+	propTxnInTrafficMeter    = metrics.NewMeter("eth/prop/txns/in/traffic")
+	propTxnOutPacketsMeter   = metrics.NewMeter("eth/prop/txns/out/packets")
+	propTxnOutTrafficMeter   = metrics.NewMeter("eth/prop/txns/out/traffic")
+	propHashInPacketsMeter   = metrics.NewMeter("eth/prop/hashes/in/packets")
+	propHashInTrafficMeter   = metrics.NewMeter("eth/prop/hashes/in/traffic")
+	propHashOutPacketsMeter  = metrics.NewMeter("eth/prop/hashes/out/packets")
+	propHashOutTrafficMeter  = metrics.NewMeter("eth/prop/hashes/out/traffic")
+	propBlockInPacketsMeter  = metrics.NewMeter("eth/prop/blocks/in/packets")
+	propBlockInTrafficMeter  = metrics.NewMeter("eth/prop/blocks/in/traffic")
+	propBlockOutPacketsMeter = metrics.NewMeter("eth/prop/blocks/out/packets")
+	propBlockOutTrafficMeter = metrics.NewMeter("eth/prop/blocks/out/traffic")
+	reqHashInPacketsMeter    = metrics.NewMeter("eth/req/hashes/in/packets")
+	reqHashInTrafficMeter    = metrics.NewMeter("eth/req/hashes/in/traffic")
+	reqHashOutPacketsMeter   = metrics.NewMeter("eth/req/hashes/out/packets")
+	reqHashOutTrafficMeter   = metrics.NewMeter("eth/req/hashes/out/traffic")
+	reqBlockInPacketsMeter   = metrics.NewMeter("eth/req/blocks/in/packets")
+	reqBlockInTrafficMeter   = metrics.NewMeter("eth/req/blocks/in/traffic")
+	reqBlockOutPacketsMeter  = metrics.NewMeter("eth/req/blocks/out/packets")
+	reqBlockOutTrafficMeter  = metrics.NewMeter("eth/req/blocks/out/traffic")
+)

eth/peer.go

@@ -20,25 +20,18 @@ var (
 	errNotRegistered     = errors.New("peer is not registered")
 )
 
-type statusMsgData struct {
-	ProtocolVersion uint32
-	NetworkId       uint32
-	TD              *big.Int
-	CurrentBlock    common.Hash
-	GenesisBlock    common.Hash
-}
-
-type getBlockHashesMsgData struct {
-	Hash   common.Hash
-	Amount uint64
-}
+const (
+	maxKnownTxs    = 32768 // Maximum transactions hashes to keep in the known list (prevent DOS)
+	maxKnownBlocks = 1024  // Maximum block hashes to keep in the known list (prevent DOS)
+)
 
 type peer struct {
 	*p2p.Peer
 
 	rw p2p.MsgReadWriter
 
-	protv, netid int
+	version int // Protocol version negotiated
+	network int // Network ID being on
 
 	id string
 
@@ -46,27 +39,21 @@ type peer struct {
 	td   *big.Int
 	lock sync.RWMutex
 
-	genesis, ourHash common.Hash
-	ourTd            *big.Int
-
-	txHashes    *set.Set
-	blockHashes *set.Set
+	knownTxs    *set.Set // Set of transaction hashes known to be known by this peer
+	knownBlocks *set.Set // Set of block hashes known to be known by this peer
 }
 
-func newPeer(protv, netid int, genesis, head common.Hash, td *big.Int, p *p2p.Peer, rw p2p.MsgReadWriter) *peer {
+func newPeer(version, network int, p *p2p.Peer, rw p2p.MsgReadWriter) *peer {
 	id := p.ID()
 
 	return &peer{
 		Peer:        p,
 		rw:          rw,
-		genesis:     genesis,
-		ourHash:     head,
-		ourTd:       td,
-		protv:       protv,
-		netid:       netid,
+		version:     version,
+		network:     network,
 		id:          fmt.Sprintf("%x", id[:8]),
-		txHashes:    set.New(),
-		blockHashes: set.New(),
+		knownTxs:    set.New(),
+		knownBlocks: set.New(),
 	}
 }
 
@@ -103,68 +90,110 @@ func (p *peer) SetTd(td *big.Int) {
 	p.td.Set(td)
 }
 
-// sendTransactions sends transactions to the peer and includes the hashes
-// in it's tx hash set for future reference. The tx hash will allow the
-// manager to check whether the peer has already received this particular
-// transaction
-func (p *peer) sendTransactions(txs types.Transactions) error {
-	for _, tx := range txs {
-		p.txHashes.Add(tx.Hash())
+// MarkBlock marks a block as known for the peer, ensuring that the block will
+// never be propagated to this particular peer.
+func (p *peer) MarkBlock(hash common.Hash) {
+	// If we reached the memory allowance, drop a previously known block hash
+	for p.knownBlocks.Size() >= maxKnownBlocks {
+		p.knownBlocks.Pop()
 	}
+	p.knownBlocks.Add(hash)
+}
 
+// MarkTransaction marks a transaction as known for the peer, ensuring that it
+// will never be propagated to this particular peer.
+func (p *peer) MarkTransaction(hash common.Hash) {
+	// If we reached the memory allowance, drop a previously known transaction hash
+	for p.knownTxs.Size() >= maxKnownTxs {
+		p.knownTxs.Pop()
+	}
+	p.knownTxs.Add(hash)
+}
+
+// SendTransactions sends transactions to the peer and includes the hashes
+// in its transaction hash set for future reference.
+func (p *peer) SendTransactions(txs types.Transactions) error {
+	propTxnOutPacketsMeter.Mark(1)
+	for _, tx := range txs {
+		propTxnOutTrafficMeter.Mark(tx.Size().Int64())
+		p.knownTxs.Add(tx.Hash())
+	}
 	return p2p.Send(p.rw, TxMsg, txs)
 }
 
-func (p *peer) sendBlockHashes(hashes []common.Hash) error {
+// SendBlockHashes sends a batch of known hashes to the remote peer.
+func (p *peer) SendBlockHashes(hashes []common.Hash) error {
+	reqHashOutPacketsMeter.Mark(1)
+	reqHashOutTrafficMeter.Mark(int64(32 * len(hashes)))
+
 	return p2p.Send(p.rw, BlockHashesMsg, hashes)
 }
 
-func (p *peer) sendBlocks(blocks []*types.Block) error {
+// SendBlocks sends a batch of blocks to the remote peer.
+func (p *peer) SendBlocks(blocks []*types.Block) error {
+	reqBlockOutPacketsMeter.Mark(1)
+	for _, block := range blocks {
+		reqBlockOutTrafficMeter.Mark(block.Size().Int64())
+	}
 	return p2p.Send(p.rw, BlocksMsg, blocks)
 }
 
-func (p *peer) sendNewBlockHashes(hashes []common.Hash) error {
+// SendNewBlockHashes announces the availability of a number of blocks through
+// a hash notification.
+func (p *peer) SendNewBlockHashes(hashes []common.Hash) error {
+	propHashOutPacketsMeter.Mark(1)
+	propHashOutTrafficMeter.Mark(int64(32 * len(hashes)))
+
 	for _, hash := range hashes {
-		p.blockHashes.Add(hash)
+		p.knownBlocks.Add(hash)
 	}
 	return p2p.Send(p.rw, NewBlockHashesMsg, hashes)
 }
 
-func (p *peer) sendNewBlock(block *types.Block) error {
-	p.blockHashes.Add(block.Hash())
+// SendNewBlock propagates an entire block to a remote peer.
+func (p *peer) SendNewBlock(block *types.Block) error {
+	propBlockOutPacketsMeter.Mark(1)
+	propBlockOutTrafficMeter.Mark(block.Size().Int64())
 
+	p.knownBlocks.Add(block.Hash())
 	return p2p.Send(p.rw, NewBlockMsg, []interface{}{block, block.Td})
 }
 
-func (p *peer) sendTransaction(tx *types.Transaction) error {
-	p.txHashes.Add(tx.Hash())
-
-	return p2p.Send(p.rw, TxMsg, []*types.Transaction{tx})
+// RequestHashes fetches a batch of hashes from a peer, starting at from, going
+// towards the genesis block.
+func (p *peer) RequestHashes(from common.Hash) error {
+	glog.V(logger.Debug).Infof("Peer [%s] fetching hashes (%d) from %x...\n", p.id, downloader.MaxHashFetch, from[:4])
+	return p2p.Send(p.rw, GetBlockHashesMsg, getBlockHashesData{from, uint64(downloader.MaxHashFetch)})
 }
 
-func (p *peer) requestHashes(from common.Hash) error {
-	glog.V(logger.Debug).Infof("[%s] fetching hashes (%d) %x...\n", p.id, downloader.MaxHashFetch, from[:4])
-	return p2p.Send(p.rw, GetBlockHashesMsg, getBlockHashesMsgData{from, uint64(downloader.MaxHashFetch)})
+// RequestHashesFromNumber fetches a batch of hashes from a peer, starting at the
+// requested block number, going upwards towards the genesis block.
+func (p *peer) RequestHashesFromNumber(from uint64, count int) error {
+	glog.V(logger.Debug).Infof("Peer [%s] fetching hashes (%d) from #%d...\n", p.id, count, from)
+	return p2p.Send(p.rw, GetBlockHashesFromNumberMsg, getBlockHashesFromNumberData{from, uint64(count)})
 }
 
-func (p *peer) requestBlocks(hashes []common.Hash) error {
+// RequestBlocks fetches a batch of blocks corresponding to the specified hashes.
+func (p *peer) RequestBlocks(hashes []common.Hash) error {
 	glog.V(logger.Debug).Infof("[%s] fetching %v blocks\n", p.id, len(hashes))
 	return p2p.Send(p.rw, GetBlocksMsg, hashes)
 }
 
-func (p *peer) handleStatus() error {
+// Handshake executes the eth protocol handshake, negotiating version number,
+// network IDs, difficulties, head and genesis blocks.
+func (p *peer) Handshake(td *big.Int, head common.Hash, genesis common.Hash) error {
+	// Send out own handshake in a new thread
 	errc := make(chan error, 1)
 	go func() {
-		errc <- p2p.Send(p.rw, StatusMsg, &statusMsgData{
-			ProtocolVersion: uint32(p.protv),
-			NetworkId:       uint32(p.netid),
-			TD:              p.ourTd,
-			CurrentBlock:    p.ourHash,
-			GenesisBlock:    p.genesis,
+		errc <- p2p.Send(p.rw, StatusMsg, &statusData{
+			ProtocolVersion: uint32(p.version),
+			NetworkId:       uint32(p.network),
+			TD:              td,
+			CurrentBlock:    head,
+			GenesisBlock:    genesis,
 		})
 	}()
-
-	// read and handle remote status
+	// In the mean time retrieve the remote status message
 	msg, err := p.rw.ReadMsg()
 	if err != nil {
 		return err
@@ -175,31 +204,32 @@ func (p *peer) handleStatus() error {
 	if msg.Size > ProtocolMaxMsgSize {
 		return errResp(ErrMsgTooLarge, "%v > %v", msg.Size, ProtocolMaxMsgSize)
 	}
-
-	var status statusMsgData
+	// Decode the handshake and make sure everything matches
+	var status statusData
 	if err := msg.Decode(&status); err != nil {
 		return errResp(ErrDecode, "msg %v: %v", msg, err)
 	}
-
-	if status.GenesisBlock != p.genesis {
-		return errResp(ErrGenesisBlockMismatch, "%x (!= %x)", status.GenesisBlock, p.genesis)
+	if status.GenesisBlock != genesis {
+		return errResp(ErrGenesisBlockMismatch, "%x (!= %x)", status.GenesisBlock, genesis)
 	}
-
-	if int(status.NetworkId) != p.netid {
-		return errResp(ErrNetworkIdMismatch, "%d (!= %d)", status.NetworkId, p.netid)
+	if int(status.NetworkId) != p.network {
+		return errResp(ErrNetworkIdMismatch, "%d (!= %d)", status.NetworkId, p.network)
 	}
-
-	if int(status.ProtocolVersion) != p.protv {
-		return errResp(ErrProtocolVersionMismatch, "%d (!= %d)", status.ProtocolVersion, p.protv)
+	if int(status.ProtocolVersion) != p.version {
+		return errResp(ErrProtocolVersionMismatch, "%d (!= %d)", status.ProtocolVersion, p.version)
 	}
-	// Set the total difficulty of the peer
-	p.td = status.TD
-	// set the best hash of the peer
-	p.head = status.CurrentBlock
-
+	// Configure the remote peer, and sanity check out handshake too
+	p.td, p.head = status.TD, status.CurrentBlock
 	return <-errc
 }
 
+// String implements fmt.Stringer.
+func (p *peer) String() string {
+	return fmt.Sprintf("Peer %s [%s]", p.id,
+		fmt.Sprintf("eth/%2d", p.version),
+	)
+}
+
 // peerSet represents the collection of active peers currently participating in
 // the Ethereum sub-protocol.
 type peerSet struct {
@@ -264,7 +294,7 @@ func (ps *peerSet) PeersWithoutBlock(hash common.Hash) []*peer {
 
 	list := make([]*peer, 0, len(ps.peers))
 	for _, p := range ps.peers {
-		if !p.blockHashes.Has(hash) {
+		if !p.knownBlocks.Has(hash) {
 			list = append(list, p)
 		}
 	}
@@ -279,7 +309,7 @@ func (ps *peerSet) PeersWithoutTx(hash common.Hash) []*peer {
 
 	list := make([]*peer, 0, len(ps.peers))
 	for _, p := range ps.peers {
-		if !p.txHashes.Has(hash) {
+		if !p.knownTxs.Has(hash) {
 			list = append(list, p)
 		}
 	}

eth/protocol.go

@@ -7,11 +7,15 @@ import (
 	"github.com/ethereum/go-ethereum/core/types"
 )
 
+// Supported versions of the eth protocol (first is primary).
+var ProtocolVersions = []uint{61, 60}
+
+// Number of implemented message corresponding to different protocol versions.
+var ProtocolLengths = []uint64{9, 8}
+
 const (
-	ProtocolVersion    = 60
 	NetworkId          = 0
-	ProtocolLength     = uint64(8)
-	ProtocolMaxMsgSize = 10 * 1024 * 1024
+	ProtocolMaxMsgSize = 10 * 1024 * 1024 // Maximum cap on the size of a protocol message
 )
 
 // eth protocol message codes
@@ -24,6 +28,7 @@ const (
 	GetBlocksMsg
 	BlocksMsg
 	NewBlockMsg
+	GetBlockHashesFromNumberMsg
 )
 
 type errCode int
@@ -72,8 +77,31 @@ type chainManager interface {
 	Status() (td *big.Int, currentBlock common.Hash, genesisBlock common.Hash)
 }
 
-// message structs used for RLP serialization
-type newBlockMsgData struct {
+// statusData is the network packet for the status message.
+type statusData struct {
+	ProtocolVersion uint32
+	NetworkId       uint32
+	TD              *big.Int
+	CurrentBlock    common.Hash
+	GenesisBlock    common.Hash
+}
+
+// getBlockHashesData is the network packet for the hash based block retrieval
+// message.
+type getBlockHashesData struct {
+	Hash   common.Hash
+	Amount uint64
+}
+
+// getBlockHashesFromNumberData is the network packet for the number based block
+// retrieval message.
+type getBlockHashesFromNumberData struct {
+	Number uint64
+	Amount uint64
+}
+
+// newBlockData is the network packet for the block propagation message.
+type newBlockData struct {
 	Block *types.Block
 	TD    *big.Int
 }

eth/protocol_test.go

@@ -39,15 +39,15 @@ func TestStatusMsgErrors(t *testing.T) {
 			wantError: errResp(ErrNoStatusMsg, "first msg has code 2 (!= 0)"),
 		},
 		{
-			code: StatusMsg, data: statusMsgData{10, NetworkId, td, currentBlock, genesis},
+			code: StatusMsg, data: statusData{10, NetworkId, td, currentBlock, genesis},
 			wantError: errResp(ErrProtocolVersionMismatch, "10 (!= 0)"),
 		},
 		{
-			code: StatusMsg, data: statusMsgData{ProtocolVersion, 999, td, currentBlock, genesis},
+			code: StatusMsg, data: statusData{uint32(ProtocolVersions[0]), 999, td, currentBlock, genesis},
 			wantError: errResp(ErrNetworkIdMismatch, "999 (!= 0)"),
 		},
 		{
-			code: StatusMsg, data: statusMsgData{ProtocolVersion, NetworkId, td, currentBlock, common.Hash{3}},
+			code: StatusMsg, data: statusData{uint32(ProtocolVersions[0]), NetworkId, td, currentBlock, common.Hash{3}},
 			wantError: errResp(ErrGenesisBlockMismatch, "0300000000000000000000000000000000000000000000000000000000000000 (!= %x)", genesis),
 		},
 	}
@@ -167,7 +167,7 @@ func newProtocolManagerForTesting(txAdded chan<- []*types.Transaction) *Protocol
 		db, _    = ethdb.NewMemDatabase()
 		chain, _ = core.NewChainManager(core.GenesisBlock(0, db), db, db, core.FakePow{}, em)
 		txpool   = &fakeTxPool{added: txAdded}
-		pm       = NewProtocolManager(ProtocolVersion, 0, em, txpool, core.FakePow{}, chain)
+		pm       = NewProtocolManager(0, em, txpool, core.FakePow{}, chain)
 	)
 	pm.Start()
 	return pm
@@ -188,7 +188,7 @@ func newTestPeer(pm *ProtocolManager) (*testPeer, <-chan error) {
 
 func (p *testPeer) handshake(t *testing.T) {
 	td, currentBlock, genesis := p.pm.chainman.Status()
-	msg := &statusMsgData{
+	msg := &statusData{
 		ProtocolVersion: uint32(p.pm.protVer),
 		NetworkId:       uint32(p.pm.netId),
 		TD:              td,

eth/sync.go

@@ -20,14 +20,6 @@ const (
 	txsyncPackSize = 100 * 1024
 )
 
-// blockAnnounce is the hash notification of the availability of a new block in
-// the network.
-type blockAnnounce struct {
-	hash common.Hash
-	peer *peer
-	time time.Time
-}
-
 type txsync struct {
 	p   *peer
 	txs []*types.Transaction
@@ -75,7 +67,7 @@ func (pm *ProtocolManager) txsyncLoop() {
 		// Send the pack in the background.
 		glog.V(logger.Detail).Infof("%v: sending %d transactions (%v)", s.p.Peer, len(pack.txs), size)
 		sending = true
-		go func() { done <- pack.p.sendTransactions(pack.txs) }()
+		go func() { done <- pack.p.SendTransactions(pack.txs) }()
 	}
 
 	// pick chooses the next pending sync.