package eth
import (
"fmt"
"math/big"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/errs"
"github.com/ethereum/go-ethereum/logger"
"github.com/ethereum/go-ethereum/p2p"
"github.com/ethereum/go-ethereum/rlp"
)
const (
ProtocolVersion = 58
NetworkId = 0
ProtocolLength = uint64(8)
ProtocolMaxMsgSize = 10 * 1024 * 1024
maxHashes = 256
maxBlocks = 64
)
// eth protocol message codes
const (
StatusMsg = iota
GetTxMsg // unused
TxMsg
GetBlockHashesMsg
BlockHashesMsg
GetBlocksMsg
BlocksMsg
NewBlockMsg
)
const (
ErrMsgTooLarge = iota
ErrDecode
ErrInvalidMsgCode
ErrProtocolVersionMismatch
ErrNetworkIdMismatch
ErrGenesisBlockMismatch
ErrNoStatusMsg
ErrExtraStatusMsg
ErrSuspendedPeer
)
var errorToString = map[int]string{
ErrMsgTooLarge: "Message too long",
ErrDecode: "Invalid message",
ErrInvalidMsgCode: "Invalid message code",
ErrProtocolVersionMismatch: "Protocol version mismatch",
ErrNetworkIdMismatch: "NetworkId mismatch",
ErrGenesisBlockMismatch: "Genesis block mismatch",
ErrNoStatusMsg: "No status message",
ErrExtraStatusMsg: "Extra status message",
ErrSuspendedPeer: "Suspended peer",
}
// ethProtocol represents the ethereum wire protocol
// instance is running on each peer
type ethProtocol struct {
txPool txPool
chainManager chainManager
blockPool blockPool
peer *p2p.Peer
id string
rw p2p.MsgReadWriter
errors *errs.Errors
protocolVersion int
networkId int
}
// backend is the interface the ethereum protocol backend should implement
// used as an argument to EthProtocol
type txPool interface {
AddTransactions([]*types.Transaction)
GetTransactions() types.Transactions
}
type chainManager interface {
GetBlockHashesFromHash(hash common.Hash, amount uint64) (hashes []common.Hash)
GetBlock(hash common.Hash) (block *types.Block)
Status() (td *big.Int, currentBlock common.Hash, genesisBlock common.Hash)
}
type blockPool interface {
AddBlockHashes(next func() (common.Hash, bool), peerId string)
AddBlock(block *types.Block, peerId string)
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)
RemovePeer(peerId string)
}
// message structs used for RLP serialization
type newBlockMsgData struct {
Block *types.Block
TD *big.Int
}
type getBlockHashesMsgData struct {
Hash common.Hash
Amount uint64
}
type statusMsgData struct {
ProtocolVersion uint32
NetworkId uint32
TD *big.Int
CurrentBlock common.Hash
GenesisBlock common.Hash
}
// main entrypoint, wrappers starting a server running the eth protocol
// use this constructor to attach the protocol ("class") to server caps
// the Dev p2p layer then runs the protocol instance on each peer
func EthProtocol(protocolVersion, networkId int, txPool txPool, chainManager chainManager, blockPool blockPool) p2p.Protocol {
return p2p.Protocol{
Name: "eth",
Version: uint(protocolVersion),
Length: ProtocolLength,
Run: func(peer *p2p.Peer, rw p2p.MsgReadWriter) error {
return runEthProtocol(protocolVersion, networkId, txPool, chainManager, blockPool, peer, rw)
},
}
}
// the main loop that handles incoming messages
// note RemovePeer in the post-disconnect hook
func runEthProtocol(protocolVersion, networkId int, txPool txPool, chainManager chainManager, blockPool blockPool, peer *p2p.Peer, rw p2p.MsgReadWriter) (err error) {
id := peer.ID()
self := ðProtocol{
txPool: txPool,
chainManager: chainManager,
blockPool: blockPool,
rw: rw,
peer: peer,
protocolVersion: protocolVersion,
networkId: networkId,
errors: &errs.Errors{
Package: "ETH",
Errors: errorToString,
},
id: fmt.Sprintf("%x", id[:8]),
}
// handshake.
if err := self.handleStatus(); err != nil {
return err
}
defer self.blockPool.RemovePeer(self.id)
// propagate existing transactions. new transactions appearing
// after this will be sent via broadcasts.
if err := p2p.Send(rw, TxMsg, txPool.GetTransactions()); err != nil {
return err
}
// main loop. handle incoming messages.
for {
if err := self.handle(); err != nil {
return err
}
}
}
func (self *ethProtocol) handle() error {
msg, err := self.rw.ReadMsg()
if err != nil {
return err
}
if msg.Size > ProtocolMaxMsgSize {
return self.protoError(ErrMsgTooLarge, "%v > %v", msg.Size, ProtocolMaxMsgSize)
}
// make sure that the payload has been fully consumed
defer msg.Discard()
switch msg.Code {
case GetTxMsg: // ignore
case StatusMsg:
return self.protoError(ErrExtraStatusMsg, "")
case TxMsg:
// TODO: rework using lazy RLP stream
var txs []*types.Transaction
if err := msg.Decode(&txs); err != nil {
return self.protoError(ErrDecode, "msg %v: %v", msg, err)
}
for _, tx := range txs {
jsonlogger.LogJson(&logger.EthTxReceived{
TxHash: tx.Hash().Hex(),
RemoteId: self.peer.ID().String(),
})
}
self.txPool.AddTransactions(txs)
case GetBlockHashesMsg:
var request getBlockHashesMsgData
if err := msg.Decode(&request); err != nil {
return self.protoError(ErrDecode, "->msg %v: %v", msg, err)
}
if request.Amount > maxHashes {
request.Amount = maxHashes
}
hashes := self.chainManager.GetBlockHashesFromHash(request.Hash, request.Amount)
return p2p.Send(self.rw, BlockHashesMsg, hashes)
case BlockHashesMsg:
msgStream := rlp.NewStream(msg.Payload)
if _, err := msgStream.List(); err != nil {
return err
}
var i int
iter := func() (hash common.Hash, ok bool) {
err := msgStream.Decode(&hash)
if err == rlp.EOL {
return common.Hash{}, false
} else if err != nil {
self.protoError(ErrDecode, "msg %v: after %v hashes : %v", msg, i, err)
return common.Hash{}, false
}
i++
return hash, true
}
self.blockPool.AddBlockHashes(iter, self.id)
case GetBlocksMsg:
msgStream := rlp.NewStream(msg.Payload)
if _, err := msgStream.List(); err != nil {
return err
}
var blocks []*types.Block
var i int
for {
i++
var hash common.Hash
err := msgStream.Decode(&hash)
if err == rlp.EOL {
break
} else if err != nil {
return self.protoError(ErrDecode, "msg %v: %v", msg, err)
}
block := self.chainManager.GetBlock(hash)
if block != nil {
blocks = append(blocks, block)
}
if i == maxBlocks {
break
}
}
return p2p.Send(self.rw, BlocksMsg, blocks)
case BlocksMsg:
msgStream := rlp.NewStream(msg.Payload)
if _, err := msgStream.List(); err != nil {
return err
}
for {
var block types.Block
if err := msgStream.Decode(&block); err != nil {
if err == rlp.EOL {
break
} else {
return self.protoError(ErrDecode, "msg %v: %v", msg, err)
}
}
self.blockPool.AddBlock(&block, self.id)
}
case NewBlockMsg:
var request newBlockMsgData
if err := msg.Decode(&request); err != nil {
return self.protoError(ErrDecode, "%v: %v", msg, err)
}
hash := request.Block.Hash()
_, chainHead, _ := self.chainManager.Status()
jsonlogger.LogJson(&logger.EthChainReceivedNewBlock{
BlockHash: hash.Hex(),
BlockNumber: request.Block.Number(), // this surely must be zero
ChainHeadHash: chainHead.Hex(),
BlockPrevHash: request.Block.ParentHash().Hex(),
RemoteId: self.peer.ID().String(),
})
// to simplify backend interface adding a new block
// uses AddPeer followed by AddBlock only if peer is the best peer
// (or selected as new best peer)
if best, _ := self.blockPool.AddPeer(request.TD, hash, self.id, self.requestBlockHashes, self.requestBlocks, self.protoErrorDisconnect); best {
self.blockPool.AddBlock(request.Block, self.id)
}
default:
return self.protoError(ErrInvalidMsgCode, "%v", msg.Code)
}
return nil
}
func (self *ethProtocol) handleStatus() error {
if err := self.sendStatus(); err != nil {
return err
}
// read and handle remote status
msg, err := self.rw.ReadMsg()
if err != nil {
return err
}
if msg.Code != StatusMsg {
return self.protoError(ErrNoStatusMsg, "first msg has code %x (!= %x)", msg.Code, StatusMsg)
}
if msg.Size > ProtocolMaxMsgSize {
return self.protoError(ErrMsgTooLarge, "%v > %v", msg.Size, ProtocolMaxMsgSize)
}
var status statusMsgData
if err := msg.Decode(&status); err != nil {
return self.protoError(ErrDecode, "msg %v: %v", msg, err)
}
_, _, genesisBlock := self.chainManager.Status()
if status.GenesisBlock != genesisBlock {
return self.protoError(ErrGenesisBlockMismatch, "%x (!= %x)", status.GenesisBlock, genesisBlock)
}
if int(status.NetworkId) != self.networkId {
return self.protoError(ErrNetworkIdMismatch, "%d (!= %d)", status.NetworkId, self.networkId)
}
if int(status.ProtocolVersion) != self.protocolVersion {
return self.protoError(ErrProtocolVersionMismatch, "%d (!= %d)", status.ProtocolVersion, self.protocolVersion)
}
_, suspended := self.blockPool.AddPeer(status.TD, status.CurrentBlock, self.id, self.requestBlockHashes, self.requestBlocks, self.protoErrorDisconnect)
if suspended {
return self.protoError(ErrSuspendedPeer, "")
}
self.peer.Infof("Peer is [eth] capable (%d/%d). TD=%v H=%x\n", status.ProtocolVersion, status.NetworkId, status.TD, status.CurrentBlock[:4])
return nil
}
func (self *ethProtocol) requestBlockHashes(from common.Hash) error {
self.peer.Debugf("fetching hashes (%d) %x...\n", maxHashes, from[0:4])
return p2p.Send(self.rw, GetBlockHashesMsg, getBlockHashesMsgData{from, maxHashes})
}
func (self *ethProtocol) requestBlocks(hashes []common.Hash) error {
self.peer.Debugf("fetching %v blocks", len(hashes))
return p2p.Send(self.rw, GetBlocksMsg, hashes)
}
func (self *ethProtocol) protoError(code int, format string, params ...interface{}) (err *errs.Error) {
err = self.errors.New(code, format, params...)
err.Log(self.peer.Logger)
return
}
func (self *ethProtocol) sendStatus() error {
td, currentBlock, genesisBlock := self.chainManager.Status()
return p2p.Send(self.rw, StatusMsg, &statusMsgData{
ProtocolVersion: uint32(self.protocolVersion),
NetworkId: uint32(self.networkId),
TD: td,
CurrentBlock: currentBlock,
GenesisBlock: genesisBlock,
})
}
func (self *ethProtocol) protoErrorDisconnect(err *errs.Error) {
err.Log(self.peer.Logger)
if err.Fatal() {
self.peer.Disconnect(p2p.DiscSubprotocolError)
}
}