les: light client protocol and API

1 files changed, 401 insertions, 0 deletions

diff --git a/les/server.go b/les/server.go
new file mode 100644
index 000000000..bc5dd0837
--- /dev/null
+++ b/les/server.go
@@ -0,0 +1,401 @@
+// Copyright 2015 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 (
+	"encoding/binary"
+	"fmt"
+	"math"
+	"sync"
+	"time"
+
+	"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/p2p"
+	"github.com/ethereum/go-ethereum/rlp"
+	"github.com/ethereum/go-ethereum/trie"
+)
+
+type LesServer struct {
+	protocolManager *ProtocolManager
+	fcManager       *flowcontrol.ClientManager // nil if our node is client only
+	fcCostStats     *requestCostStats
+	defParams       *flowcontrol.ServerParams
+}
+
+func NewLesServer(eth *eth.Ethereum, config *eth.Config) (*LesServer, error) {
+	pm, err := NewProtocolManager(config.ChainConfig, false, config.NetworkId, eth.EventMux(), eth.Pow(), eth.BlockChain(), eth.TxPool(), eth.ChainDb(), nil, nil)
+	if err != nil {
+		return nil, err
+	}
+	pm.blockLoop()
+
+	srv := &LesServer{protocolManager: pm}
+	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
+}
+
+func (s *LesServer) Start() {
+	s.protocolManager.Start()
+}
+
+func (s *LesServer) Stop() {
+	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
+}
+
+func (table requestCostTable) encode() RequestCostList {
+	list := make(RequestCostList, len(table))
+	for idx, code := range reqList {
+		list[idx].MsgCode = code
+		list[idx].BaseCost = table[code].baseCost
+		list[idx].ReqCost = table[code].reqCost
+	}
+	return list
+}
+
+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)
+	sub := pm.eventMux.Subscribe(core.ChainHeadEvent{})
+	newCht := make(chan struct{}, 10)
+	newCht <- struct{}{}
+	go func() {
+		var mu sync.Mutex
+		var lastHead *types.Header
+		lastBroadcastTd := common.Big0
+		for {
+			select {
+			case ev := <-sub.Chan():
+				peers := pm.peers.AllPeers()
+				if len(peers) > 0 {
+					header := ev.Data.(core.ChainHeadEvent).Block.Header()
+					hash := header.Hash()
+					number := header.GetNumberU64()
+					td := core.GetTd(pm.chainDb, hash, number)
+					if td != nil && td.Cmp(lastBroadcastTd) > 0 {
+						var reorg uint64
+						if lastHead != nil {
+							reorg = lastHead.GetNumberU64() - core.FindCommonAncestor(pm.chainDb, header, lastHead).GetNumberU64()
+						}
+						lastHead = header
+						lastBroadcastTd = td
+						//fmt.Println("BROADCAST", number, hash, td, reorg)
+						announce := announceData{Hash: hash, Number: number, Td: td, ReorgDepth: reorg}
+						for _, p := range peers {
+							select {
+							case p.announceChn <- announce:
+							default:
+								pm.removePeer(p.id)
+							}
+						}
+					}
+				}
+				newCht <- struct{}{}
+			case <-newCht:
+				go func() {
+					mu.Lock()
+					more := makeCht(pm.chainDb)
+					mu.Unlock()
+					if more {
+						time.Sleep(time.Millisecond * 10)
+						newCht <- struct{}{}
+					}
+				}()
+			case <-pm.quitSync:
+				sub.Unsubscribe()
+				pm.wg.Done()
+				return
+			}
+		}
+	}()
+}
+
+var (
+	lastChtKey       = []byte("LastChtNumber") // chtNum (uint64 big endian)
+	chtPrefix        = []byte("cht")           // chtPrefix + chtNum (uint64 big endian) -> trie root hash
+	chtConfirmations = light.ChtFrequency / 2
+)
+
+func getChtRoot(db ethdb.Database, num uint64) common.Hash {
+	var encNumber [8]byte
+	binary.BigEndian.PutUint64(encNumber[:], num)
+	data, _ := db.Get(append(chtPrefix, encNumber[:]...))
+	return common.BytesToHash(data)
+}
+
+func storeChtRoot(db ethdb.Database, num uint64, root common.Hash) {
+	var encNumber [8]byte
+	binary.BigEndian.PutUint64(encNumber[:], num)
+	db.Put(append(chtPrefix, encNumber[:]...), root[:])
+}
+
+func makeCht(db ethdb.Database) bool {
+	headHash := core.GetHeadBlockHash(db)
+	headNum := core.GetBlockNumber(db, headHash)
+
+	var newChtNum uint64
+	if headNum > chtConfirmations {
+		newChtNum = (headNum - chtConfirmations) / light.ChtFrequency
+	}
+
+	var lastChtNum uint64
+	data, _ := db.Get(lastChtKey)
+	if len(data) == 8 {
+		lastChtNum = binary.BigEndian.Uint64(data[:])
+	}
+	if newChtNum <= lastChtNum {
+		return false
+	}
+
+	var t *trie.Trie
+	if lastChtNum > 0 {
+		var err error
+		t, err = trie.New(getChtRoot(db, lastChtNum), db)
+		if err != nil {
+			lastChtNum = 0
+		}
+	}
+	if lastChtNum == 0 {
+		t, _ = trie.New(common.Hash{}, db)
+	}
+
+	for num := lastChtNum * light.ChtFrequency; num < (lastChtNum+1)*light.ChtFrequency; num++ {
+		hash := core.GetCanonicalHash(db, num)
+		if hash == (common.Hash{}) {
+			panic("Canonical hash not found")
+		}
+		td := core.GetTd(db, hash, num)
+		if td == nil {
+			panic("TD not found")
+		}
+		var encNumber [8]byte
+		binary.BigEndian.PutUint64(encNumber[:], num)
+		var node light.ChtNode
+		node.Hash = hash
+		node.Td = td
+		data, _ := rlp.EncodeToBytes(node)
+		t.Update(encNumber[:], data)
+	}
+
+	root, err := t.Commit()
+	if err != nil {
+		lastChtNum = 0
+	} else {
+		lastChtNum++
+		fmt.Printf("CHT %d %064x\n", lastChtNum, root)
+		storeChtRoot(db, lastChtNum, root)
+		var data [8]byte
+		binary.BigEndian.PutUint64(data[:], lastChtNum)
+		db.Put(lastChtKey, data[:])
+	}
+
+	return newChtNum > lastChtNum
+}