plugeth/les/client_handler.go
Felföldi Zsolt b4a2681120
les, les/lespay: implement new server pool (#20758)
This PR reimplements the light client server pool. It is also a first step
to move certain logic into a new lespay package. This package will contain
the implementation of the lespay token sale functions, the token buying and
selling logic and other components related to peer selection/prioritization
and service quality evaluation. Over the long term this package will be
reusable for incentivizing future protocols.

Since the LES peer logic is now based on enode.Iterator, it can now use
DNS-based fallback discovery to find servers.

This document describes the function of the new components:
https://gist.github.com/zsfelfoldi/3c7ace895234b7b345ab4f71dab102d4
2020-05-22 13:46:34 +02:00

409 lines
12 KiB
Go

// 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"
"sync/atomic"
"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.
syncDone func() // Test hooks when syncing is done.
}
func newClientHandler(ulcServers []string, ulcFraction int, checkpoint *params.TrustedCheckpoint, backend *LightEthereum) *clientHandler {
handler := &clientHandler{
checkpoint: checkpoint,
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, backend.serverPool.getTimeout)
handler.downloader = downloader.New(height, backend.chainDb, nil, backend.eventMux, nil, backend.blockchain, handler.removePeer)
handler.backend.peers.subscribe((*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 := newServerPeer(int(version), h.backend.config.NetworkId, trusted, p, newMeteredMsgWriter(rw, int(version)))
defer peer.close()
h.wg.Add(1)
defer h.wg.Done()
err := h.handle(peer)
return err
}
func (h *clientHandler) handle(p *serverPeer) 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, &announceData{Hash: p.headInfo.Hash, Number: p.headInfo.Number, Td: p.headInfo.Td})
// Mark the peer starts to be served.
atomic.StoreUint32(&p.serving, 1)
defer atomic.StoreUint32(&p.serving, 0)
// 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 *serverPeer) 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)
p.updateVtParams()
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)
p.answeredRequest(resp.ReqID)
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)
p.answeredRequest(resp.ReqID)
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)
p.answeredRequest(resp.ReqID)
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)
p.answeredRequest(resp.ReqID)
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)
p.answeredRequest(resp.ReqID)
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)
p.answeredRequest(resp.ReqID)
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)
p.answeredRequest(resp.ReqID)
deliverMsg = &Msg{
MsgType: MsgTxStatus,
ReqID: resp.ReqID,
Obj: resp.Status,
}
case StopMsg:
p.freeze()
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.unfreeze()
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.errCount++
if p.errCount > maxResponseErrors {
return err
}
}
}
return nil
}
func (h *clientHandler) removePeer(id string) {
h.backend.peers.unregister(id)
}
type peerConnection struct {
handler *clientHandler
peer *serverPeer
}
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.(*serverPeer)
return peer.getRequestCost(GetBlockHeadersMsg, amount)
},
canSend: func(dp distPeer) bool {
return dp.(*serverPeer) == pc.peer
},
request: func(dp distPeer) func() {
reqID := genReqID()
peer := dp.(*serverPeer)
cost := peer.getRequestCost(GetBlockHeadersMsg, amount)
peer.fcServer.QueuedRequest(reqID, cost)
return func() { peer.requestHeadersByHash(reqID, 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.(*serverPeer)
return peer.getRequestCost(GetBlockHeadersMsg, amount)
},
canSend: func(dp distPeer) bool {
return dp.(*serverPeer) == pc.peer
},
request: func(dp distPeer) func() {
reqID := genReqID()
peer := dp.(*serverPeer)
cost := peer.getRequestCost(GetBlockHeadersMsg, amount)
peer.fcServer.QueuedRequest(reqID, cost)
return func() { peer.requestHeadersByNumber(reqID, 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 *serverPeer) {
h := (*clientHandler)(d)
pc := &peerConnection{
handler: h,
peer: p,
}
h.downloader.RegisterLightPeer(p.id, ethVersion, pc)
}
func (d *downloaderPeerNotify) unregisterPeer(p *serverPeer) {
h := (*clientHandler)(d)
h.downloader.UnregisterPeer(p.id)
}