go-ethereum/les/server_handler.go

435 lines
14 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 (
"errors"
"sync"
"sync/atomic"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/common/mclock"
"github.com/ethereum/go-ethereum/core"
"github.com/ethereum/go-ethereum/core/forkid"
"github.com/ethereum/go-ethereum/core/rawdb"
"github.com/ethereum/go-ethereum/core/state"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/ethdb"
"github.com/ethereum/go-ethereum/les/flowcontrol"
"github.com/ethereum/go-ethereum/light"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/metrics"
"github.com/ethereum/go-ethereum/p2p"
"github.com/ethereum/go-ethereum/rlp"
"github.com/ethereum/go-ethereum/trie"
)
const (
softResponseLimit = 2 * 1024 * 1024 // Target maximum size of returned blocks, headers or node data.
estHeaderRlpSize = 500 // Approximate size of an RLP encoded block header
MaxHeaderFetch = 192 // Amount of block headers to be fetched per retrieval request
MaxBodyFetch = 32 // Amount of block bodies to be fetched per retrieval request
MaxReceiptFetch = 128 // Amount of transaction receipts to allow fetching per request
MaxCodeFetch = 64 // Amount of contract codes to allow fetching per request
MaxProofsFetch = 64 // Amount of merkle proofs to be fetched per retrieval request
MaxHelperTrieProofsFetch = 64 // Amount of helper tries to be fetched per retrieval request
MaxTxSend = 64 // Amount of transactions to be send per request
MaxTxStatus = 256 // Amount of transactions to queried per request
)
var (
errTooManyInvalidRequest = errors.New("too many invalid requests made")
)
// serverHandler is responsible for serving light client and process
// all incoming light requests.
type serverHandler struct {
forkFilter forkid.Filter
blockchain *core.BlockChain
chainDb ethdb.Database
txpool *core.TxPool
server *LesServer
closeCh chan struct{} // Channel used to exit all background routines of handler.
wg sync.WaitGroup // WaitGroup used to track all background routines of handler.
synced func() bool // Callback function used to determine whether local node is synced.
// Testing fields
addTxsSync bool
}
func newServerHandler(server *LesServer, blockchain *core.BlockChain, chainDb ethdb.Database, txpool *core.TxPool, synced func() bool) *serverHandler {
handler := &serverHandler{
forkFilter: forkid.NewFilter(blockchain),
server: server,
blockchain: blockchain,
chainDb: chainDb,
txpool: txpool,
closeCh: make(chan struct{}),
synced: synced,
}
return handler
}
// start starts the server handler.
func (h *serverHandler) start() {
h.wg.Add(1)
go h.broadcastLoop()
}
// stop stops the server handler.
func (h *serverHandler) stop() {
close(h.closeCh)
h.wg.Wait()
}
// runPeer is the p2p protocol run function for the given version.
func (h *serverHandler) runPeer(version uint, p *p2p.Peer, rw p2p.MsgReadWriter) error {
peer := newClientPeer(int(version), h.server.config.NetworkId, p, newMeteredMsgWriter(rw, int(version)))
defer peer.close()
h.wg.Add(1)
defer h.wg.Done()
return h.handle(peer)
}
func (h *serverHandler) handle(p *clientPeer) error {
p.Log().Debug("Light Ethereum peer connected", "name", p.Name())
// Execute the LES handshake
var (
head = h.blockchain.CurrentHeader()
hash = head.Hash()
number = head.Number.Uint64()
td = h.blockchain.GetTd(hash, number)
forkID = forkid.NewID(h.blockchain.Config(), h.blockchain.Genesis().Hash(), h.blockchain.CurrentBlock().NumberU64())
)
if err := p.Handshake(td, hash, number, h.blockchain.Genesis().Hash(), forkID, h.forkFilter, h.server); err != nil {
p.Log().Debug("Light Ethereum handshake failed", "err", err)
return err
}
// Connected to another server, no messages expected, just wait for disconnection
if p.server {
if err := h.server.serverset.register(p); err != nil {
return err
}
_, err := p.rw.ReadMsg()
h.server.serverset.unregister(p)
return err
}
// Setup flow control mechanism for the peer
p.fcClient = flowcontrol.NewClientNode(h.server.fcManager, p.fcParams)
defer p.fcClient.Disconnect()
// Reject light clients if server is not synced. Put this checking here, so
// that "non-synced" les-server peers are still allowed to keep the connection.
if !h.synced() {
p.Log().Debug("Light server not synced, rejecting peer")
return p2p.DiscRequested
}
// Register the peer into the peerset and clientpool
if err := h.server.peers.register(p); err != nil {
return err
}
if p.balance = h.server.clientPool.Register(p); p.balance == nil {
h.server.peers.unregister(p.ID())
p.Log().Debug("Client pool already closed")
return p2p.DiscRequested
}
p.connectedAt = mclock.Now()
var wg sync.WaitGroup // Wait group used to track all in-flight task routines.
defer func() {
wg.Wait() // Ensure all background task routines have exited.
h.server.clientPool.Unregister(p)
h.server.peers.unregister(p.ID())
p.balance = nil
connectionTimer.Update(time.Duration(mclock.Now() - p.connectedAt))
}()
// Mark the peer as being served.
atomic.StoreUint32(&p.serving, 1)
defer atomic.StoreUint32(&p.serving, 0)
// Spawn a main loop to handle all incoming messages.
for {
select {
case err := <-p.errCh:
p.Log().Debug("Failed to send light ethereum response", "err", err)
return err
default:
}
if err := h.handleMsg(p, &wg); err != nil {
p.Log().Debug("Light Ethereum message handling failed", "err", err)
return err
}
}
}
// beforeHandle will do a series of prechecks before handling message.
func (h *serverHandler) beforeHandle(p *clientPeer, reqID, responseCount uint64, msg p2p.Msg, reqCnt uint64, maxCount uint64) (*servingTask, uint64) {
// Ensure that the request sent by client peer is valid
inSizeCost := h.server.costTracker.realCost(0, msg.Size, 0)
if reqCnt == 0 || reqCnt > maxCount {
p.fcClient.OneTimeCost(inSizeCost)
return nil, 0
}
// Ensure that the client peer complies with the flow control
// rules agreed by both sides.
if p.isFrozen() {
p.fcClient.OneTimeCost(inSizeCost)
return nil, 0
}
maxCost := p.fcCosts.getMaxCost(msg.Code, reqCnt)
accepted, bufShort, priority := p.fcClient.AcceptRequest(reqID, responseCount, maxCost)
if !accepted {
p.freeze()
p.Log().Error("Request came too early", "remaining", common.PrettyDuration(time.Duration(bufShort*1000000/p.fcParams.MinRecharge)))
p.fcClient.OneTimeCost(inSizeCost)
return nil, 0
}
// Create a multi-stage task, estimate the time it takes for the task to
// execute, and cache it in the request service queue.
factor := h.server.costTracker.globalFactor()
if factor < 0.001 {
factor = 1
p.Log().Error("Invalid global cost factor", "factor", factor)
}
maxTime := uint64(float64(maxCost) / factor)
task := h.server.servingQueue.newTask(p, maxTime, priority)
if !task.start() {
p.fcClient.RequestProcessed(reqID, responseCount, maxCost, inSizeCost)
return nil, 0
}
return task, maxCost
}
// Afterhandle will perform a series of operations after message handling,
// such as updating flow control data, sending reply, etc.
func (h *serverHandler) afterHandle(p *clientPeer, reqID, responseCount uint64, msg p2p.Msg, maxCost uint64, reqCnt uint64, task *servingTask, reply *reply) {
if reply != nil {
task.done()
}
p.responseLock.Lock()
defer p.responseLock.Unlock()
// Short circuit if the client is already frozen.
if p.isFrozen() {
realCost := h.server.costTracker.realCost(task.servingTime, msg.Size, 0)
p.fcClient.RequestProcessed(reqID, responseCount, maxCost, realCost)
return
}
// Positive correction buffer value with real cost.
var replySize uint32
if reply != nil {
replySize = reply.size()
}
var realCost uint64
if h.server.costTracker.testing {
realCost = maxCost // Assign a fake cost for testing purpose
} else {
realCost = h.server.costTracker.realCost(task.servingTime, msg.Size, replySize)
if realCost > maxCost {
realCost = maxCost
}
}
bv := p.fcClient.RequestProcessed(reqID, responseCount, maxCost, realCost)
if reply != nil {
// Feed cost tracker request serving statistic.
h.server.costTracker.updateStats(msg.Code, reqCnt, task.servingTime, realCost)
// Reduce priority "balance" for the specific peer.
p.balance.RequestServed(realCost)
p.queueSend(func() {
if err := reply.send(bv); err != nil {
select {
case p.errCh <- err:
default:
}
}
})
}
}
// 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 *serverHandler) handleMsg(p *clientPeer, wg *sync.WaitGroup) 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)
// Discard large message which exceeds the limitation.
if msg.Size > ProtocolMaxMsgSize {
clientErrorMeter.Mark(1)
return errResp(ErrMsgTooLarge, "%v > %v", msg.Size, ProtocolMaxMsgSize)
}
defer msg.Discard()
// Lookup the request handler table, ensure it's supported
// message type by the protocol.
req, ok := Les3[msg.Code]
if !ok {
p.Log().Trace("Received invalid message", "code", msg.Code)
clientErrorMeter.Mark(1)
return errResp(ErrInvalidMsgCode, "%v", msg.Code)
}
p.Log().Trace("Received " + req.Name)
// Decode the p2p message, resolve the concrete handler for it.
serve, reqID, reqCnt, err := req.Handle(msg)
if err != nil {
clientErrorMeter.Mark(1)
return errResp(ErrDecode, "%v: %v", msg, err)
}
if metrics.EnabledExpensive {
req.InPacketsMeter.Mark(1)
req.InTrafficMeter.Mark(int64(msg.Size))
}
p.responseCount++
responseCount := p.responseCount
// First check this client message complies all rules before
// handling it and return a processor if all checks are passed.
task, maxCost := h.beforeHandle(p, reqID, responseCount, msg, reqCnt, req.MaxCount)
if task == nil {
return nil
}
wg.Add(1)
go func() {
defer wg.Done()
reply := serve(h, p, task.waitOrStop)
h.afterHandle(p, reqID, responseCount, msg, maxCost, reqCnt, task, reply)
if metrics.EnabledExpensive {
size := uint32(0)
if reply != nil {
size = reply.size()
}
req.OutPacketsMeter.Mark(1)
req.OutTrafficMeter.Mark(int64(size))
req.ServingTimeMeter.Update(time.Duration(task.servingTime))
}
}()
// If the client has made too much invalid request(e.g. request a non-existent data),
// reject them to prevent SPAM attack.
if p.getInvalid() > maxRequestErrors {
clientErrorMeter.Mark(1)
return errTooManyInvalidRequest
}
return nil
}
// BlockChain implements serverBackend
func (h *serverHandler) BlockChain() *core.BlockChain {
return h.blockchain
}
// TxPool implements serverBackend
func (h *serverHandler) TxPool() *core.TxPool {
return h.txpool
}
// ArchiveMode implements serverBackend
func (h *serverHandler) ArchiveMode() bool {
return h.server.archiveMode
}
// AddTxsSync implements serverBackend
func (h *serverHandler) AddTxsSync() bool {
return h.addTxsSync
}
// getAccount retrieves an account from the state based on root.
func getAccount(triedb *trie.Database, root, hash common.Hash) (state.Account, error) {
trie, err := trie.New(root, triedb)
if err != nil {
return state.Account{}, err
}
blob, err := trie.TryGet(hash[:])
if err != nil {
return state.Account{}, err
}
var account state.Account
if err = rlp.DecodeBytes(blob, &account); err != nil {
return state.Account{}, err
}
return account, nil
}
// getHelperTrie returns the post-processed trie root for the given trie ID and section index
func (h *serverHandler) GetHelperTrie(typ uint, index uint64) *trie.Trie {
var (
root common.Hash
prefix string
)
switch typ {
case htCanonical:
sectionHead := rawdb.ReadCanonicalHash(h.chainDb, (index+1)*h.server.iConfig.ChtSize-1)
root, prefix = light.GetChtRoot(h.chainDb, index, sectionHead), light.ChtTablePrefix
case htBloomBits:
sectionHead := rawdb.ReadCanonicalHash(h.chainDb, (index+1)*h.server.iConfig.BloomTrieSize-1)
root, prefix = light.GetBloomTrieRoot(h.chainDb, index, sectionHead), light.BloomTrieTablePrefix
}
if root == (common.Hash{}) {
return nil
}
trie, _ := trie.New(root, trie.NewDatabase(rawdb.NewTable(h.chainDb, prefix)))
return trie
}
// broadcastLoop broadcasts new block information to all connected light
// clients. According to the agreement between client and server, server should
// only broadcast new announcement if the total difficulty is higher than the
// last one. Besides server will add the signature if client requires.
func (h *serverHandler) broadcastLoop() {
defer h.wg.Done()
headCh := make(chan core.ChainHeadEvent, 10)
headSub := h.blockchain.SubscribeChainHeadEvent(headCh)
defer headSub.Unsubscribe()
var (
lastHead *types.Header
lastTd = common.Big0
)
for {
select {
case ev := <-headCh:
header := ev.Block.Header()
hash, number := header.Hash(), header.Number.Uint64()
td := h.blockchain.GetTd(hash, number)
if td == nil || td.Cmp(lastTd) <= 0 {
continue
}
var reorg uint64
if lastHead != nil {
reorg = lastHead.Number.Uint64() - rawdb.FindCommonAncestor(h.chainDb, header, lastHead).Number.Uint64()
}
lastHead, lastTd = header, td
log.Debug("Announcing block to peers", "number", number, "hash", hash, "td", td, "reorg", reorg)
h.server.peers.broadcast(announceData{Hash: hash, Number: number, Td: td, ReorgDepth: reorg})
case <-h.closeCh:
return
}
}
}