plugeth/eth/protocol.go
2014-12-14 20:27:05 +00:00

295 lines
7.3 KiB
Go

package eth
import (
"bytes"
"math"
"math/big"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/ethutil"
ethlogger "github.com/ethereum/go-ethereum/logger"
"github.com/ethereum/go-ethereum/p2p"
)
var logger = ethlogger.NewLogger("SERV")
// ethProtocol represents the ethereum wire protocol
// instance is running on each peer
type ethProtocol struct {
eth backend
td *big.Int
peer *p2p.Peer
rw p2p.MsgReadWriter
}
// backend is the interface the ethereum protocol backend should implement
// used as an argument to EthProtocol
type backend interface {
GetTransactions() (txs []*types.Transaction)
AddTransactions(txs []*types.Transaction)
GetBlockHashes(hash []byte, amount uint32) (hashes [][]byte)
AddHash(hash []byte, peer *p2p.Peer) (more bool)
GetBlock(hash []byte) (block *types.Block)
AddBlock(td *big.Int, block *types.Block, peer *p2p.Peer) (fetchHashes bool, err error)
AddPeer(td *big.Int, currentBlock []byte, peer *p2p.Peer) (fetchHashes bool)
Status() (td *big.Int, currentBlock []byte, genesisBlock []byte)
}
const (
ProtocolVersion = 43
// 0x00 // PoC-1
// 0x01 // PoC-2
// 0x07 // PoC-3
// 0x09 // PoC-4
// 0x17 // PoC-5
// 0x1c // PoC-6
NetworkId = 0
ProtocolLength = uint64(8)
ProtocolMaxMsgSize = 10 * 1024 * 1024
blockHashesBatchSize = 256
)
// eth protocol message codes
const (
StatusMsg = iota
GetTxMsg // unused
TxMsg
GetBlockHashesMsg
BlockHashesMsg
GetBlocksMsg
BlocksMsg
NewBlockMsg
)
// message structs used for rlp decoding
type newBlockMsgData struct {
Block *types.Block
TD *big.Int
}
type getBlockHashesMsgData struct {
Hash []byte
Amount uint32
}
// main entrypoint, wrappers starting a server running the eth protocol
// use this constructor to attach the protocol (class) to server caps
func EthProtocol(eth backend) *p2p.Protocol {
return &p2p.Protocol{
Name: "eth",
Version: ProtocolVersion,
Length: ProtocolLength,
Run: func(peer *p2p.Peer, rw p2p.MsgReadWriter) error {
return runEthProtocol(eth, peer, rw)
},
}
}
func runEthProtocol(eth backend, peer *p2p.Peer, rw p2p.MsgReadWriter) (err error) {
self := &ethProtocol{
eth: eth,
rw: rw,
peer: peer,
}
err = self.handleStatus()
if err == nil {
go func() {
for {
err = self.handle()
if err != nil {
break
}
}
}()
}
return
}
func (self *ethProtocol) handle() error {
msg, err := self.rw.ReadMsg()
if err != nil {
return err
}
if msg.Size > ProtocolMaxMsgSize {
return ProtocolError(ErrMsgTooLarge, "%v > %v", msg.Size, ProtocolMaxMsgSize)
}
// make sure that the payload has been fully consumed
defer msg.Discard()
switch msg.Code {
case StatusMsg:
return ProtocolError(ErrExtraStatusMsg, "")
case GetTxMsg:
txs := self.eth.GetTransactions()
// TODO: rewrite using rlp flat
txsInterface := make([]interface{}, len(txs))
for i, tx := range txs {
txsInterface[i] = tx.RlpData()
}
return self.rw.EncodeMsg(TxMsg, txsInterface...)
case TxMsg:
var txs []*types.Transaction
if err := msg.Decode(&txs); err != nil {
return ProtocolError(ErrDecode, "%v", err)
}
self.eth.AddTransactions(txs)
case GetBlockHashesMsg:
var request getBlockHashesMsgData
if err := msg.Decode(&request); err != nil {
return ProtocolError(ErrDecode, "%v", err)
}
hashes := self.eth.GetBlockHashes(request.Hash, request.Amount)
return self.rw.EncodeMsg(BlockHashesMsg, ethutil.ByteSliceToInterface(hashes)...)
case BlockHashesMsg:
// TODO: redo using lazy decode , this way very inefficient on known chains
// s := rlp.NewListStream(msg.Payload, uint64(msg.Size))
var blockHashes [][]byte
if err := msg.Decode(&blockHashes); err != nil {
return ProtocolError(ErrDecode, "%v", err)
}
fetchMore := true
for _, hash := range blockHashes {
fetchMore = self.eth.AddHash(hash, self.peer)
if !fetchMore {
break
}
}
if fetchMore {
return self.FetchHashes(blockHashes[len(blockHashes)-1])
}
case GetBlocksMsg:
// Limit to max 300 blocks
var blockHashes [][]byte
if err := msg.Decode(&blockHashes); err != nil {
return ProtocolError(ErrDecode, "%v", err)
}
max := int(math.Min(float64(len(blockHashes)), 300.0))
var blocks []interface{}
for i, hash := range blockHashes {
if i >= max {
break
}
block := self.eth.GetBlock(hash)
if block != nil {
blocks = append(blocks, block.Value().Raw())
}
}
return self.rw.EncodeMsg(BlocksMsg, blocks...)
case BlocksMsg:
var blocks []*types.Block
if err := msg.Decode(&blocks); err != nil {
return ProtocolError(ErrDecode, "%v", err)
}
for _, block := range blocks {
fetchHashes, err := self.eth.AddBlock(nil, block, self.peer)
if err != nil {
return ProtocolError(ErrInvalidBlock, "%v", err)
}
if fetchHashes {
if err := self.FetchHashes(block.Hash()); err != nil {
return err
}
}
}
case NewBlockMsg:
var request newBlockMsgData
if err := msg.Decode(&request); err != nil {
return ProtocolError(ErrDecode, "%v", err)
}
var fetchHashes bool
// this should reset td and offer blockpool as candidate new peer?
if fetchHashes, err = self.eth.AddBlock(request.TD, request.Block, self.peer); err != nil {
return ProtocolError(ErrInvalidBlock, "%v", err)
}
if fetchHashes {
return self.FetchHashes(request.Block.Hash())
}
default:
return ProtocolError(ErrInvalidMsgCode, "%v", msg.Code)
}
return nil
}
type statusMsgData struct {
ProtocolVersion uint
NetworkId uint
TD *big.Int
CurrentBlock []byte
GenesisBlock []byte
}
func (self *ethProtocol) statusMsg() p2p.Msg {
td, currentBlock, genesisBlock := self.eth.Status()
return p2p.NewMsg(StatusMsg,
uint32(ProtocolVersion),
uint32(NetworkId),
td,
currentBlock,
genesisBlock,
)
}
func (self *ethProtocol) handleStatus() error {
// send precanned status message
if err := self.rw.WriteMsg(self.statusMsg()); err != nil {
return err
}
// read and handle remote status
msg, err := self.rw.ReadMsg()
if err != nil {
return err
}
if msg.Code != StatusMsg {
return ProtocolError(ErrNoStatusMsg, "first msg has code %x (!= %x)", msg.Code, StatusMsg)
}
if msg.Size > ProtocolMaxMsgSize {
return ProtocolError(ErrMsgTooLarge, "%v > %v", msg.Size, ProtocolMaxMsgSize)
}
var status statusMsgData
if err := msg.Decode(&status); err != nil {
return ProtocolError(ErrDecode, "%v", err)
}
_, _, genesisBlock := self.eth.Status()
if bytes.Compare(status.GenesisBlock, genesisBlock) != 0 {
return ProtocolError(ErrGenesisBlockMismatch, "%x (!= %x)", status.GenesisBlock, genesisBlock)
}
if status.NetworkId != NetworkId {
return ProtocolError(ErrNetworkIdMismatch, "%d (!= %d)", status.NetworkId, NetworkId)
}
if ProtocolVersion != status.ProtocolVersion {
return ProtocolError(ErrProtocolVersionMismatch, "%d (!= %d)", status.ProtocolVersion, ProtocolVersion)
}
logger.Infof("Peer is [eth] capable (%d/%d). TD = %v ~ %x", status.ProtocolVersion, status.NetworkId, status.CurrentBlock)
if self.eth.AddPeer(status.TD, status.CurrentBlock, self.peer) {
return self.FetchHashes(status.CurrentBlock)
}
return nil
}
func (self *ethProtocol) FetchHashes(from []byte) error {
logger.Debugf("Fetching hashes (%d) %x...\n", blockHashesBatchSize, from[0:4])
return self.rw.EncodeMsg(GetBlockHashesMsg, from, blockHashesBatchSize)
}