381 lines
		
	
	
		
			10 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
			
		
		
	
	
			381 lines
		
	
	
		
			10 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
package eth
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import (
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	"fmt"
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	"math/big"
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	"github.com/ethereum/go-ethereum/common"
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	"github.com/ethereum/go-ethereum/core/types"
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	"github.com/ethereum/go-ethereum/errs"
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	"github.com/ethereum/go-ethereum/logger"
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	"github.com/ethereum/go-ethereum/p2p"
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	"github.com/ethereum/go-ethereum/rlp"
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)
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const (
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	ProtocolVersion    = 59
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	NetworkId          = 0
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	ProtocolLength     = uint64(8)
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	ProtocolMaxMsgSize = 10 * 1024 * 1024
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	maxHashes          = 256
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	maxBlocks          = 64
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)
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// eth protocol message codes
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const (
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	StatusMsg = iota
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	GetTxMsg  // unused
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	TxMsg
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	GetBlockHashesMsg
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	BlockHashesMsg
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	GetBlocksMsg
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	BlocksMsg
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	NewBlockMsg
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)
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const (
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	ErrMsgTooLarge = iota
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	ErrDecode
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	ErrInvalidMsgCode
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	ErrProtocolVersionMismatch
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	ErrNetworkIdMismatch
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	ErrGenesisBlockMismatch
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	ErrNoStatusMsg
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	ErrExtraStatusMsg
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	ErrSuspendedPeer
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)
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var errorToString = map[int]string{
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	ErrMsgTooLarge:             "Message too long",
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	ErrDecode:                  "Invalid message",
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	ErrInvalidMsgCode:          "Invalid message code",
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	ErrProtocolVersionMismatch: "Protocol version mismatch",
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	ErrNetworkIdMismatch:       "NetworkId mismatch",
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	ErrGenesisBlockMismatch:    "Genesis block mismatch",
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	ErrNoStatusMsg:             "No status message",
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	ErrExtraStatusMsg:          "Extra status message",
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	ErrSuspendedPeer:           "Suspended peer",
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}
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// ethProtocol represents the ethereum wire protocol
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// instance is running on each peer
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type ethProtocol struct {
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	txPool          txPool
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	chainManager    chainManager
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	blockPool       blockPool
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	peer            *p2p.Peer
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	id              string
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	rw              p2p.MsgReadWriter
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	errors          *errs.Errors
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	protocolVersion int
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	networkId       int
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}
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// backend is the interface the ethereum protocol backend should implement
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// used as an argument to EthProtocol
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type txPool interface {
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	AddTransactions([]*types.Transaction)
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	GetTransactions() types.Transactions
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}
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type chainManager interface {
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	GetBlockHashesFromHash(hash common.Hash, amount uint64) (hashes []common.Hash)
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	GetBlock(hash common.Hash) (block *types.Block)
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	Status() (td *big.Int, currentBlock common.Hash, genesisBlock common.Hash)
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}
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type blockPool interface {
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	AddBlockHashes(next func() (common.Hash, bool), peerId string)
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	AddBlock(block *types.Block, peerId string)
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	AddPeer(td *big.Int, currentBlock common.Hash, peerId string, requestHashes func(common.Hash) error, requestBlocks func([]common.Hash) error, peerError func(*errs.Error)) (best bool, suspended bool)
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	RemovePeer(peerId string)
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}
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// message structs used for RLP serialization
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type newBlockMsgData struct {
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	Block *types.Block
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	TD    *big.Int
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}
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type getBlockHashesMsgData struct {
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	Hash   common.Hash
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	Amount uint64
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}
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type statusMsgData struct {
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	ProtocolVersion uint32
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	NetworkId       uint32
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	TD              *big.Int
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	CurrentBlock    common.Hash
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	GenesisBlock    common.Hash
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}
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// main entrypoint, wrappers starting a server running the eth protocol
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// use this constructor to attach the protocol ("class") to server caps
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// the Dev p2p layer then runs the protocol instance on each peer
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func EthProtocol(protocolVersion, networkId int, txPool txPool, chainManager chainManager, blockPool blockPool) p2p.Protocol {
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	return p2p.Protocol{
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		Name:    "eth",
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		Version: uint(protocolVersion),
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		Length:  ProtocolLength,
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		Run: func(peer *p2p.Peer, rw p2p.MsgReadWriter) error {
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			return runEthProtocol(protocolVersion, networkId, txPool, chainManager, blockPool, peer, rw)
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		},
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	}
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}
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// the main loop that handles incoming messages
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// note RemovePeer in the post-disconnect hook
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func runEthProtocol(protocolVersion, networkId int, txPool txPool, chainManager chainManager, blockPool blockPool, peer *p2p.Peer, rw p2p.MsgReadWriter) (err error) {
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	id := peer.ID()
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	self := ðProtocol{
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		txPool:          txPool,
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		chainManager:    chainManager,
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		blockPool:       blockPool,
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		rw:              rw,
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		peer:            peer,
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		protocolVersion: protocolVersion,
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		networkId:       networkId,
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		errors: &errs.Errors{
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			Package: "ETH",
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			Errors:  errorToString,
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		},
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		id: fmt.Sprintf("%x", id[:8]),
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	}
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	// handshake.
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	if err := self.handleStatus(); err != nil {
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		return err
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	}
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	defer self.blockPool.RemovePeer(self.id)
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	// propagate existing transactions. new transactions appearing
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	// after this will be sent via broadcasts.
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	if err := p2p.Send(rw, TxMsg, txPool.GetTransactions()); err != nil {
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		return err
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	}
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	// main loop. handle incoming messages.
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	for {
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		if err := self.handle(); err != nil {
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			return err
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		}
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	}
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}
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func (self *ethProtocol) handle() error {
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	msg, err := self.rw.ReadMsg()
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	if err != nil {
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		return err
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	}
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	if msg.Size > ProtocolMaxMsgSize {
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		return self.protoError(ErrMsgTooLarge, "%v > %v", msg.Size, ProtocolMaxMsgSize)
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	}
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	// make sure that the payload has been fully consumed
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	defer msg.Discard()
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	switch msg.Code {
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	case GetTxMsg: // ignore
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	case StatusMsg:
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		return self.protoError(ErrExtraStatusMsg, "")
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	case TxMsg:
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		// TODO: rework using lazy RLP stream
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		var txs []*types.Transaction
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		if err := msg.Decode(&txs); err != nil {
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			return self.protoError(ErrDecode, "msg %v: %v", msg, err)
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		}
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		for _, tx := range txs {
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			jsonlogger.LogJson(&logger.EthTxReceived{
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				TxHash:   tx.Hash().Hex(),
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				RemoteId: self.peer.ID().String(),
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			})
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		}
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		self.txPool.AddTransactions(txs)
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	case GetBlockHashesMsg:
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		var request getBlockHashesMsgData
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		if err := msg.Decode(&request); err != nil {
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			return self.protoError(ErrDecode, "->msg %v: %v", msg, err)
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		}
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		if request.Amount > maxHashes {
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			request.Amount = maxHashes
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		}
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		hashes := self.chainManager.GetBlockHashesFromHash(request.Hash, request.Amount)
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		return p2p.Send(self.rw, BlockHashesMsg, hashes)
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	case BlockHashesMsg:
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		msgStream := rlp.NewStream(msg.Payload)
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		if _, err := msgStream.List(); err != nil {
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			return err
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		}
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		var i int
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		iter := func() (hash common.Hash, ok bool) {
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			err := msgStream.Decode(&hash)
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			if err == rlp.EOL {
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				return common.Hash{}, false
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			} else if err != nil {
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				self.protoError(ErrDecode, "msg %v: after %v hashes : %v", msg, i, err)
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				return common.Hash{}, false
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			}
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			i++
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			return hash, true
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		}
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		self.blockPool.AddBlockHashes(iter, self.id)
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	case GetBlocksMsg:
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		msgStream := rlp.NewStream(msg.Payload)
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		if _, err := msgStream.List(); err != nil {
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			return err
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		}
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		var blocks []*types.Block
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		var i int
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		for {
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			i++
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			var hash common.Hash
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			err := msgStream.Decode(&hash)
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			if err == rlp.EOL {
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				break
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			} else if err != nil {
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				return self.protoError(ErrDecode, "msg %v: %v", msg, err)
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			}
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			block := self.chainManager.GetBlock(hash)
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			if block != nil {
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				blocks = append(blocks, block)
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			}
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			if i == maxBlocks {
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				break
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			}
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		}
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		return p2p.Send(self.rw, BlocksMsg, blocks)
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	case BlocksMsg:
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		msgStream := rlp.NewStream(msg.Payload)
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		if _, err := msgStream.List(); err != nil {
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			return err
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		}
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		for {
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			var block types.Block
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			if err := msgStream.Decode(&block); err != nil {
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				if err == rlp.EOL {
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					break
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				} else {
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					return self.protoError(ErrDecode, "msg %v: %v", msg, err)
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				}
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			}
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			self.blockPool.AddBlock(&block, self.id)
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		}
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	case NewBlockMsg:
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		var request newBlockMsgData
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		if err := msg.Decode(&request); err != nil {
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			return self.protoError(ErrDecode, "%v: %v", msg, err)
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		}
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		hash := request.Block.Hash()
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		_, chainHead, _ := self.chainManager.Status()
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		jsonlogger.LogJson(&logger.EthChainReceivedNewBlock{
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			BlockHash:     hash.Hex(),
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			BlockNumber:   request.Block.Number(), // this surely must be zero
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			ChainHeadHash: chainHead.Hex(),
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			BlockPrevHash: request.Block.ParentHash().Hex(),
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			RemoteId:      self.peer.ID().String(),
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		})
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		// to simplify backend interface adding a new block
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		// uses AddPeer followed by AddBlock only if peer is the best peer
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		// (or selected as new best peer)
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		if best, _ := self.blockPool.AddPeer(request.TD, hash, self.id, self.requestBlockHashes, self.requestBlocks, self.protoErrorDisconnect); best {
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			self.blockPool.AddBlock(request.Block, self.id)
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		}
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	default:
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		return self.protoError(ErrInvalidMsgCode, "%v", msg.Code)
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	}
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	return nil
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}
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func (self *ethProtocol) handleStatus() error {
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	if err := self.sendStatus(); err != nil {
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		return err
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	}
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	// read and handle remote status
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	msg, err := self.rw.ReadMsg()
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	if err != nil {
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		return err
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	}
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	if msg.Code != StatusMsg {
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		return self.protoError(ErrNoStatusMsg, "first msg has code %x (!= %x)", msg.Code, StatusMsg)
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	}
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	if msg.Size > ProtocolMaxMsgSize {
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		return self.protoError(ErrMsgTooLarge, "%v > %v", msg.Size, ProtocolMaxMsgSize)
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	}
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	var status statusMsgData
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	if err := msg.Decode(&status); err != nil {
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		return self.protoError(ErrDecode, "msg %v: %v", msg, err)
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	}
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	_, _, genesisBlock := self.chainManager.Status()
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	if status.GenesisBlock != genesisBlock {
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		return self.protoError(ErrGenesisBlockMismatch, "%x (!= %x)", status.GenesisBlock, genesisBlock)
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	}
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	if int(status.NetworkId) != self.networkId {
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		return self.protoError(ErrNetworkIdMismatch, "%d (!= %d)", status.NetworkId, self.networkId)
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	}
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	if int(status.ProtocolVersion) != self.protocolVersion {
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		return self.protoError(ErrProtocolVersionMismatch, "%d (!= %d)", status.ProtocolVersion, self.protocolVersion)
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	}
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	_, suspended := self.blockPool.AddPeer(status.TD, status.CurrentBlock, self.id, self.requestBlockHashes, self.requestBlocks, self.protoErrorDisconnect)
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	if suspended {
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		return self.protoError(ErrSuspendedPeer, "")
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	}
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	self.peer.Infof("Peer is [eth] capable (%d/%d). TD=%v H=%x\n", status.ProtocolVersion, status.NetworkId, status.TD, status.CurrentBlock[:4])
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	return nil
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}
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func (self *ethProtocol) requestBlockHashes(from common.Hash) error {
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	self.peer.Debugf("fetching hashes (%d) %x...\n", maxHashes, from[0:4])
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	return p2p.Send(self.rw, GetBlockHashesMsg, getBlockHashesMsgData{from, maxHashes})
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}
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func (self *ethProtocol) requestBlocks(hashes []common.Hash) error {
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	self.peer.Debugf("fetching %v blocks", len(hashes))
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	return p2p.Send(self.rw, GetBlocksMsg, hashes)
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}
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func (self *ethProtocol) protoError(code int, format string, params ...interface{}) (err *errs.Error) {
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	err = self.errors.New(code, format, params...)
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	err.Log(self.peer.Logger)
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	return
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}
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func (self *ethProtocol) sendStatus() error {
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	td, currentBlock, genesisBlock := self.chainManager.Status()
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	return p2p.Send(self.rw, StatusMsg, &statusMsgData{
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		ProtocolVersion: uint32(self.protocolVersion),
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		NetworkId:       uint32(self.networkId),
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		TD:              td,
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		CurrentBlock:    currentBlock,
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		GenesisBlock:    genesisBlock,
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	})
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}
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func (self *ethProtocol) protoErrorDisconnect(err *errs.Error) {
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	err.Log(self.peer.Logger)
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	if err.Fatal() {
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		self.peer.Disconnect(p2p.DiscSubprotocolError)
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	}
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}
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