path: root/les/server.go

// Copyright 2016 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 implements the Light Ethereum Subprotocol.
package les

import (
    "crypto/ecdsa"
    "encoding/binary"
    "math"
    "sync"

    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/core"
    "github.com/ethereum/go-ethereum/core/types"
    "github.com/ethereum/go-ethereum/eth"
    "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/p2p"
    "github.com/ethereum/go-ethereum/p2p/discv5"
    "github.com/ethereum/go-ethereum/rlp"
)

type LesServer struct {
    config          *eth.Config
    protocolManager *ProtocolManager
    fcManager       *flowcontrol.ClientManager // nil if our node is client only
    fcCostStats     *requestCostStats
    defParams       *flowcontrol.ServerParams
    lesTopics       []discv5.Topic
    privateKey      *ecdsa.PrivateKey
    quitSync        chan struct{}

    chtIndexer, bloomTrieIndexer *core.ChainIndexer
}

func NewLesServer(eth *eth.Ethereum, config *eth.Config) (*LesServer, error) {
    quitSync := make(chan struct{})
    pm, err := NewProtocolManager(eth.BlockChain().Config(), false, ServerProtocolVersions, config.NetworkId, eth.EventMux(), eth.Engine(), newPeerSet(), eth.BlockChain(), eth.TxPool(), eth.ChainDb(), nil, nil, quitSync, new(sync.WaitGroup))
    if err != nil {
        return nil, err
    }

    lesTopics := make([]discv5.Topic, len(AdvertiseProtocolVersions))
    for i, pv := range AdvertiseProtocolVersions {
        lesTopics[i] = lesTopic(eth.BlockChain().Genesis().Hash(), pv)
    }

    srv := &LesServer{
        config:           config,
        protocolManager:  pm,
        quitSync:         quitSync,
        lesTopics:        lesTopics,
        chtIndexer:       light.NewChtIndexer(eth.ChainDb(), false),
        bloomTrieIndexer: light.NewBloomTrieIndexer(eth.ChainDb(), false),
    }
    logger := log.New()

    chtV1SectionCount, _, _ := srv.chtIndexer.Sections() // indexer still uses LES/1 4k section size for backwards server compatibility
    chtV2SectionCount := chtV1SectionCount / (light.CHTFrequencyClient / light.CHTFrequencyServer)
    if chtV2SectionCount != 0 {
        // convert to LES/2 section
        chtLastSection := chtV2SectionCount - 1
        // convert last LES/2 section index back to LES/1 index for chtIndexer.SectionHead
        chtLastSectionV1 := (chtLastSection+1)*(light.CHTFrequencyClient/light.CHTFrequencyServer) - 1
        chtSectionHead := srv.chtIndexer.SectionHead(chtLastSectionV1)
        chtRoot := light.GetChtV2Root(pm.chainDb, chtLastSection, chtSectionHead)
        logger.Info("Loaded CHT", "section", chtLastSection, "head", chtSectionHead, "root", chtRoot)
    }
    bloomTrieSectionCount, _, _ := srv.bloomTrieIndexer.Sections()
    if bloomTrieSectionCount != 0 {
        bloomTrieLastSection := bloomTrieSectionCount - 1
        bloomTrieSectionHead := srv.bloomTrieIndexer.SectionHead(bloomTrieLastSection)
        bloomTrieRoot := light.GetBloomTrieRoot(pm.chainDb, bloomTrieLastSection, bloomTrieSectionHead)
        logger.Info("Loaded bloom trie", "section", bloomTrieLastSection, "head", bloomTrieSectionHead, "root", bloomTrieRoot)
    }

    srv.chtIndexer.Start(eth.BlockChain())
    pm.server = srv

    srv.defParams = &flowcontrol.ServerParams{
        BufLimit:    300000000,
        MinRecharge: 50000,
    }
    srv.fcManager = flowcontrol.NewClientManager(uint64(config.LightServ), 10, 1000000000)
    srv.fcCostStats = newCostStats(eth.ChainDb())
    return srv, nil
}

func (s *LesServer) Protocols() []p2p.Protocol {
    return s.protocolManager.SubProtocols
}

// Start starts the LES server
func (s *LesServer) Start(srvr *p2p.Server) {
    s.protocolManager.Start(s.config.LightPeers)
    if srvr.DiscV5 != nil {
        for _, topic := range s.lesTopics {
            topic := topic
            go func() {
                logger := log.New("topic", topic)
                logger.Info("Starting topic registration")
                defer logger.Info("Terminated topic registration")

                srvr.DiscV5.RegisterTopic(topic, s.quitSync)
            }()
        }
    }
    s.privateKey = srvr.PrivateKey
    s.protocolManager.blockLoop()
}

func (s *LesServer) SetBloomBitsIndexer(bloomIndexer *core.ChainIndexer) {
    bloomIndexer.AddChildIndexer(s.bloomTrieIndexer)
}

// Stop stops the LES service
func (s *LesServer) Stop() {
    s.chtIndexer.Close()
    // bloom trie indexer is closed by parent bloombits indexer
    s.fcCostStats.store()
    s.fcManager.Stop()
    go func() {
        <-s.protocolManager.noMorePeers
    }()
    s.protocolManager.Stop()
}

type requestCosts struct {
    baseCost, reqCost uint64
}

type requestCostTable map[uint64]*requestCosts

type RequestCostList []struct {
    MsgCode, BaseCost, ReqCost uint64
}

func (list RequestCostList) decode() requestCostTable {
    table := make(requestCostTable)
    for _, e := range list {
        table[e.MsgCode] = &requestCosts{
            baseCost: e.BaseCost,
            reqCost:  e.ReqCost,
        }
    }
    return table
}

type linReg struct {
    sumX, sumY, sumXX, sumXY float64
    cnt                      uint64
}

const linRegMaxCnt = 100000

func (l *linReg) add(x, y float64) {
    if l.cnt >= linRegMaxCnt {
        sub := float64(l.cnt+1-linRegMaxCnt) / linRegMaxCnt
        l.sumX -= l.sumX * sub
        l.sumY -= l.sumY * sub
        l.sumXX -= l.sumXX * sub
        l.sumXY -= l.sumXY * sub
        l.cnt = linRegMaxCnt - 1
    }
    l.cnt++
    l.sumX += x
    l.sumY += y
    l.sumXX += x * x
    l.sumXY += x * y
}

func (l *linReg) calc() (b, m float64) {
    if l.cnt == 0 {
        return 0, 0
    }
    cnt := float64(l.cnt)
    d := cnt*l.sumXX - l.sumX*l.sumX
    if d < 0.001 {
        return l.sumY / cnt, 0
    }
    m = (cnt*l.sumXY - l.sumX*l.sumY) / d
    b = (l.sumY / cnt) - (m * l.sumX / cnt)
    return b, m
}

func (l *linReg) toBytes() []byte {
    var arr [40]byte
    binary.BigEndian.PutUint64(arr[0:8], math.Float64bits(l.sumX))
    binary.BigEndian.PutUint64(arr[8:16], math.Float64bits(l.sumY))
    binary.BigEndian.PutUint64(arr[16:24], math.Float64bits(l.sumXX))
    binary.BigEndian.PutUint64(arr[24:32], math.Float64bits(l.sumXY))
    binary.BigEndian.PutUint64(arr[32:40], l.cnt)
    return arr[:]
}

func linRegFromBytes(data []byte) *linReg {
    if len(data) != 40 {
        return nil
    }
    l := &linReg{}
    l.sumX = math.Float64frombits(binary.BigEndian.Uint64(data[0:8]))
    l.sumY = math.Float64frombits(binary.BigEndian.Uint64(data[8:16]))
    l.sumXX = math.Float64frombits(binary.BigEndian.Uint64(data[16:24]))
    l.sumXY = math.Float64frombits(binary.BigEndian.Uint64(data[24:32]))
    l.cnt = binary.BigEndian.Uint64(data[32:40])
    return l
}

type requestCostStats struct {
    lock  sync.RWMutex
    db    ethdb.Database
    stats map[uint64]*linReg
}

type requestCostStatsRlp []struct {
    MsgCode uint64
    Data    []byte
}

var rcStatsKey = []byte("_requestCostStats")

func newCostStats(db ethdb.Database) *requestCostStats {
    stats := make(map[uint64]*linReg)
    for _, code := range reqList {
        stats[code] = &linReg{cnt: 100}
    }

    if db != nil {
        data, err := db.Get(rcStatsKey)
        var statsRlp requestCostStatsRlp
        if err == nil {
            err = rlp.DecodeBytes(data, &statsRlp)
        }
        if err == nil {
            for _, r := range statsRlp {
                if stats[r.MsgCode] != nil {
                    if l := linRegFromBytes(r.Data); l != nil {
                        stats[r.MsgCode] = l
                    }
                }
            }
        }
    }

    return &requestCostStats{
        db:    db,
        stats: stats,
    }
}

func (s *requestCostStats) store() {
    s.lock.Lock()
    defer s.lock.Unlock()

    statsRlp := make(requestCostStatsRlp, len(reqList))
    for i, code := range reqList {
        statsRlp[i].MsgCode = code
        statsRlp[i].Data = s.stats[code].toBytes()
    }

    if data, err := rlp.EncodeToBytes(statsRlp); err == nil {
        s.db.Put(rcStatsKey, data)
    }
}

func (s *requestCostStats) getCurrentList() RequestCostList {
    s.lock.Lock()
    defer s.lock.Unlock()

    list := make(RequestCostList, len(reqList))
    //fmt.Println("RequestCostList")
    for idx, code := range reqList {
        b, m := s.stats[code].calc()
        //fmt.Println(code, s.stats[code].cnt, b/1000000, m/1000000)
        if m < 0 {
            b += m
            m = 0
        }
        if b < 0 {
            b = 0
        }

        list[idx].MsgCode = code
        list[idx].BaseCost = uint64(b * 2)
        list[idx].ReqCost = uint64(m * 2)
    }
    return list
}

func (s *requestCostStats) update(msgCode, reqCnt, cost uint64) {
    s.lock.Lock()
    defer s.lock.Unlock()

    c, ok := s.stats[msgCode]
    if !ok || reqCnt == 0 {
        return
    }
    c.add(float64(reqCnt), float64(cost))
}

func (pm *ProtocolManager) blockLoop() {
    pm.wg.Add(1)
    headCh := make(chan core.ChainHeadEvent, 10)
    headSub := pm.blockchain.SubscribeChainHeadEvent(headCh)
    go func() {
        var lastHead *types.Header
        lastBroadcastTd := common.Big0
        for {
            select {
            case ev := <-headCh:
                peers := pm.peers.AllPeers()
                if len(peers) > 0 {
                    header := ev.Block.Header()
                    hash := header.Hash()
                    number := header.Number.Uint64()
                    td := core.GetTd(pm.chainDb, hash, number)
                    if td != nil && td.Cmp(lastBroadcastTd) > 0 {
                        var reorg uint64
                        if lastHead != nil {
                            reorg = lastHead.Number.Uint64() - core.FindCommonAncestor(pm.chainDb, header, lastHead).Number.Uint64()
                        }
                        lastHead = header
                        lastBroadcastTd = td

                        log.Debug("Announcing block to peers", "number", number, "hash", hash, "td", td, "reorg", reorg)

                        announce := announceData{Hash: hash, Number: number, Td: td, ReorgDepth: reorg}
                        var (
                            signed         bool
                            signedAnnounce announceData
                        )

                        for _, p := range peers {
                            switch p.announceType {

                            case announceTypeSimple:
                                select {
                                case p.announceChn <- announce:
                                default:
                                    pm.removePeer(p.id)
                                }

                            case announceTypeSigned:
                                if !signed {
                                    signedAnnounce = announce
                                    signedAnnounce.sign(pm.server.privateKey)
                                    signed = true
                                }

                                select {
                                case p.announceChn <- signedAnnounce:
                                default:
                                    pm.removePeer(p.id)
                                }
                            }
                        }
                    }
                }
            case <-pm.quitSync:
                headSub.Unsubscribe()
                pm.wg.Done()
                return
            }
        }
    }()
}