// Copyright 2019 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package les
import (
"math/big"
"sync"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/common/mclock"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/eth/downloader"
"github.com/ethereum/go-ethereum/light"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/p2p"
"github.com/ethereum/go-ethereum/params"
)
// clientHandler is responsible for receiving and processing all incoming server
// responses.
type clientHandler struct {
ulc *ulc
checkpoint *params.TrustedCheckpoint
fetcher *lightFetcher
downloader *downloader.Downloader
backend *LightEthereum
closeCh chan struct{}
wg sync.WaitGroup // WaitGroup used to track all connected peers.
}
func newClientHandler(ulcServers []string, ulcFraction int, checkpoint *params.TrustedCheckpoint, backend *LightEthereum) *clientHandler {
handler := &clientHandler{
backend: backend,
closeCh: make(chan struct{}),
}
if ulcServers != nil {
ulc, err := newULC(ulcServers, ulcFraction)
if err != nil {
log.Error("Failed to initialize ultra light client")
}
handler.ulc = ulc
log.Info("Enable ultra light client mode")
}
var height uint64
if checkpoint != nil {
height = (checkpoint.SectionIndex+1)*params.CHTFrequency - 1
}
handler.fetcher = newLightFetcher(handler)
handler.downloader = downloader.New(height, backend.chainDb, nil, backend.eventMux, nil, backend.blockchain, handler.removePeer)
handler.backend.peers.notify((*downloaderPeerNotify)(handler))
return handler
}
func (h *clientHandler) stop() {
close(h.closeCh)
h.downloader.Terminate()
h.fetcher.close()
h.wg.Wait()
}
// runPeer is the p2p protocol run function for the given version.
func (h *clientHandler) runPeer(version uint, p *p2p.Peer, rw p2p.MsgReadWriter) error {
trusted := false
if h.ulc != nil {
trusted = h.ulc.trusted(p.ID())
}
peer := newPeer(int(version), h.backend.config.NetworkId, trusted, p, newMeteredMsgWriter(rw, int(version)))
peer.poolEntry = h.backend.serverPool.connect(peer, peer.Node())
if peer.poolEntry == nil {
return p2p.DiscRequested
}
h.wg.Add(1)
defer h.wg.Done()
err := h.handle(peer)
h.backend.serverPool.disconnect(peer.poolEntry)
return err
}
func (h *clientHandler) handle(p *peer) error {
if h.backend.peers.Len() >= h.backend.config.LightPeers && !p.Peer.Info().Network.Trusted {
return p2p.DiscTooManyPeers
}
p.Log().Debug("Light Ethereum peer connected", "name", p.Name())
// Execute the LES handshake
var (
head = h.backend.blockchain.CurrentHeader()
hash = head.Hash()
number = head.Number.Uint64()
td = h.backend.blockchain.GetTd(hash, number)
)
if err := p.Handshake(td, hash, number, h.backend.blockchain.Genesis().Hash(), nil); err != nil {
p.Log().Debug("Light Ethereum handshake failed", "err", err)
return err
}
// Register the peer locally
if err := h.backend.peers.Register(p); err != nil {
p.Log().Error("Light Ethereum peer registration failed", "err", err)
return err
}
serverConnectionGauge.Update(int64(h.backend.peers.Len()))
connectedAt := mclock.Now()
defer func() {
h.backend.peers.Unregister(p.id)
connectionTimer.Update(time.Duration(mclock.Now() - connectedAt))
serverConnectionGauge.Update(int64(h.backend.peers.Len()))
}()
h.fetcher.announce(p, p.headInfo)
// pool entry can be nil during the unit test.
if p.poolEntry != nil {
h.backend.serverPool.registered(p.poolEntry)
}
// Spawn a main loop to handle all incoming messages.
for {
if err := h.handleMsg(p); err != nil {
p.Log().Debug("Light Ethereum message handling failed", "err", err)
p.fcServer.DumpLogs()
return err
}
}
}
// handleMsg is invoked whenever an inbound message is received from a remote
// peer. The remote connection is torn down upon returning any error.
func (h *clientHandler) handleMsg(p *peer) error {
// Read the next message from the remote peer, and ensure it's fully consumed
msg, err := p.rw.ReadMsg()
if err != nil {
return err
}
p.Log().Trace("Light Ethereum message arrived", "code", msg.Code, "bytes", msg.Size)
if msg.Size > ProtocolMaxMsgSize {
return errResp(ErrMsgTooLarge, "%v > %v", msg.Size, ProtocolMaxMsgSize)
}
defer msg.Discard()
var deliverMsg *Msg
// Handle the message depending on its contents
switch msg.Code {
case AnnounceMsg:
p.Log().Trace("Received announce message")
var req announceData
if err := msg.Decode(&req); err != nil {
return errResp(ErrDecode, "%v: %v", msg, err)
}
if err := req.sanityCheck(); err != nil {
return err
}
update, size := req.Update.decode()
if p.rejectUpdate(size) {
return errResp(ErrRequestRejected, "")
}
p.updateFlowControl(update)
if req.Hash != (common.Hash{}) {
if p.announceType == announceTypeNone {
return errResp(ErrUnexpectedResponse, "")
}
if p.announceType == announceTypeSigned {
if err := req.checkSignature(p.ID(), update); err != nil {
p.Log().Trace("Invalid announcement signature", "err", err)
return err
}
p.Log().Trace("Valid announcement signature")
}
p.Log().Trace("Announce message content", "number", req.Number, "hash", req.Hash, "td", req.Td, "reorg", req.ReorgDepth)
h.fetcher.announce(p, &req)
}
case BlockHeadersMsg:
p.Log().Trace("Received block header response message")
var resp struct {
ReqID, BV uint64
Headers []*types.Header
}
if err := msg.Decode(&resp); err != nil {
return errResp(ErrDecode, "msg %v: %v", msg, err)
}
p.fcServer.ReceivedReply(resp.ReqID, resp.BV)
if h.fetcher.requestedID(resp.ReqID) {
h.fetcher.deliverHeaders(p, resp.ReqID, resp.Headers)
} else {
if err := h.downloader.DeliverHeaders(p.id, resp.Headers); err != nil {
log.Debug("Failed to deliver headers", "err", err)
}
}
case BlockBodiesMsg:
p.Log().Trace("Received block bodies response")
var resp struct {
ReqID, BV uint64
Data []*types.Body
}
if err := msg.Decode(&resp); err != nil {
return errResp(ErrDecode, "msg %v: %v", msg, err)
}
p.fcServer.ReceivedReply(resp.ReqID, resp.BV)
deliverMsg = &Msg{
MsgType: MsgBlockBodies,
ReqID: resp.ReqID,
Obj: resp.Data,
}
case CodeMsg:
p.Log().Trace("Received code response")
var resp struct {
ReqID, BV uint64
Data [][]byte
}
if err := msg.Decode(&resp); err != nil {
return errResp(ErrDecode, "msg %v: %v", msg, err)
}
p.fcServer.ReceivedReply(resp.ReqID, resp.BV)
deliverMsg = &Msg{
MsgType: MsgCode,
ReqID: resp.ReqID,
Obj: resp.Data,
}
case ReceiptsMsg:
p.Log().Trace("Received receipts response")
var resp struct {
ReqID, BV uint64
Receipts []types.Receipts
}
if err := msg.Decode(&resp); err != nil {
return errResp(ErrDecode, "msg %v: %v", msg, err)
}
p.fcServer.ReceivedReply(resp.ReqID, resp.BV)
deliverMsg = &Msg{
MsgType: MsgReceipts,
ReqID: resp.ReqID,
Obj: resp.Receipts,
}
case ProofsV2Msg:
p.Log().Trace("Received les/2 proofs response")
var resp struct {
ReqID, BV uint64
Data light.NodeList
}
if err := msg.Decode(&resp); err != nil {
return errResp(ErrDecode, "msg %v: %v", msg, err)
}
p.fcServer.ReceivedReply(resp.ReqID, resp.BV)
deliverMsg = &Msg{
MsgType: MsgProofsV2,
ReqID: resp.ReqID,
Obj: resp.Data,
}
case HelperTrieProofsMsg:
p.Log().Trace("Received helper trie proof response")
var resp struct {
ReqID, BV uint64
Data HelperTrieResps
}
if err := msg.Decode(&resp); err != nil {
return errResp(ErrDecode, "msg %v: %v", msg, err)
}
p.fcServer.ReceivedReply(resp.ReqID, resp.BV)
deliverMsg = &Msg{
MsgType: MsgHelperTrieProofs,
ReqID: resp.ReqID,
Obj: resp.Data,
}
case TxStatusMsg:
p.Log().Trace("Received tx status response")
var resp struct {
ReqID, BV uint64
Status []light.TxStatus
}
if err := msg.Decode(&resp); err != nil {
return errResp(ErrDecode, "msg %v: %v", msg, err)
}
p.fcServer.ReceivedReply(resp.ReqID, resp.BV)
deliverMsg = &Msg{
MsgType: MsgTxStatus,
ReqID: resp.ReqID,
Obj: resp.Status,
}
case StopMsg:
p.freezeServer(true)
h.backend.retriever.frozen(p)
p.Log().Debug("Service stopped")
case ResumeMsg:
var bv uint64
if err := msg.Decode(&bv); err != nil {
return errResp(ErrDecode, "msg %v: %v", msg, err)
}
p.fcServer.ResumeFreeze(bv)
p.freezeServer(false)
p.Log().Debug("Service resumed")
default:
p.Log().Trace("Received invalid message", "code", msg.Code)
return errResp(ErrInvalidMsgCode, "%v", msg.Code)
}
// Deliver the received response to retriever.
if deliverMsg != nil {
if err := h.backend.retriever.deliver(p, deliverMsg); err != nil {
p.responseErrors++
if p.responseErrors > maxResponseErrors {
return err
}
}
}
return nil
}
func (h *clientHandler) removePeer(id string) {
h.backend.peers.Unregister(id)
}
type peerConnection struct {
handler *clientHandler
peer *peer
}
func (pc *peerConnection) Head() (common.Hash, *big.Int) {
return pc.peer.HeadAndTd()
}
func (pc *peerConnection) RequestHeadersByHash(origin common.Hash, amount int, skip int, reverse bool) error {
rq := &distReq{
getCost: func(dp distPeer) uint64 {
peer := dp.(*peer)
return peer.GetRequestCost(GetBlockHeadersMsg, amount)
},
canSend: func(dp distPeer) bool {
return dp.(*peer) == pc.peer
},
request: func(dp distPeer) func() {
reqID := genReqID()
peer := dp.(*peer)
cost := peer.GetRequestCost(GetBlockHeadersMsg, amount)
peer.fcServer.QueuedRequest(reqID, cost)
return func() { peer.RequestHeadersByHash(reqID, cost, origin, amount, skip, reverse) }
},
}
_, ok := <-pc.handler.backend.reqDist.queue(rq)
if !ok {
return light.ErrNoPeers
}
return nil
}
func (pc *peerConnection) RequestHeadersByNumber(origin uint64, amount int, skip int, reverse bool) error {
rq := &distReq{
getCost: func(dp distPeer) uint64 {
peer := dp.(*peer)
return peer.GetRequestCost(GetBlockHeadersMsg, amount)
},
canSend: func(dp distPeer) bool {
return dp.(*peer) == pc.peer
},
request: func(dp distPeer) func() {
reqID := genReqID()
peer := dp.(*peer)
cost := peer.GetRequestCost(GetBlockHeadersMsg, amount)
peer.fcServer.QueuedRequest(reqID, cost)
return func() { peer.RequestHeadersByNumber(reqID, cost, origin, amount, skip, reverse) }
},
}
_, ok := <-pc.handler.backend.reqDist.queue(rq)
if !ok {
return light.ErrNoPeers
}
return nil
}
// downloaderPeerNotify implements peerSetNotify
type downloaderPeerNotify clientHandler
func (d *downloaderPeerNotify) registerPeer(p *peer) {
h := (*clientHandler)(d)
pc := &peerConnection{
handler: h,
peer: p,
}
h.downloader.RegisterLightPeer(p.id, ethVersion, pc)
}
func (d *downloaderPeerNotify) unregisterPeer(p *peer) {
h := (*clientHandler)(d)
h.downloader.UnregisterPeer(p.id)
}
