plugeth/les/odr.go

237 lines
7.1 KiB
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
import (
"context"
"math/rand"
"sort"
"time"
"github.com/ethereum/go-ethereum/common/mclock"
"github.com/ethereum/go-ethereum/core"
"github.com/ethereum/go-ethereum/ethdb"
"github.com/ethereum/go-ethereum/light"
)
// LesOdr implements light.OdrBackend
type LesOdr struct {
db ethdb.Database
indexerConfig *light.IndexerConfig
chtIndexer, bloomTrieIndexer, bloomIndexer *core.ChainIndexer
peers *serverPeerSet
retriever *retrieveManager
stop chan struct{}
}
func NewLesOdr(db ethdb.Database, config *light.IndexerConfig, peers *serverPeerSet, retriever *retrieveManager) *LesOdr {
return &LesOdr{
db: db,
indexerConfig: config,
peers: peers,
retriever: retriever,
stop: make(chan struct{}),
}
}
// Stop cancels all pending retrievals
func (odr *LesOdr) Stop() {
close(odr.stop)
}
// Database returns the backing database
func (odr *LesOdr) Database() ethdb.Database {
return odr.db
}
// SetIndexers adds the necessary chain indexers to the ODR backend
func (odr *LesOdr) SetIndexers(chtIndexer, bloomTrieIndexer, bloomIndexer *core.ChainIndexer) {
odr.chtIndexer = chtIndexer
odr.bloomTrieIndexer = bloomTrieIndexer
odr.bloomIndexer = bloomIndexer
}
// ChtIndexer returns the CHT chain indexer
func (odr *LesOdr) ChtIndexer() *core.ChainIndexer {
return odr.chtIndexer
}
// BloomTrieIndexer returns the bloom trie chain indexer
func (odr *LesOdr) BloomTrieIndexer() *core.ChainIndexer {
return odr.bloomTrieIndexer
}
// BloomIndexer returns the bloombits chain indexer
func (odr *LesOdr) BloomIndexer() *core.ChainIndexer {
return odr.bloomIndexer
}
// IndexerConfig returns the indexer config.
func (odr *LesOdr) IndexerConfig() *light.IndexerConfig {
return odr.indexerConfig
}
const (
MsgBlockHeaders = iota
MsgBlockBodies
MsgCode
MsgReceipts
MsgProofsV2
MsgHelperTrieProofs
MsgTxStatus
)
// Msg encodes a LES message that delivers reply data for a request
type Msg struct {
MsgType int
ReqID uint64
Obj interface{}
}
// peerByTxHistory is a heap.Interface implementation which can sort
// the peerset by transaction history.
type peerByTxHistory []*serverPeer
func (h peerByTxHistory) Len() int { return len(h) }
func (h peerByTxHistory) Less(i, j int) bool {
if h[i].txHistory == txIndexUnlimited {
return false
}
if h[j].txHistory == txIndexUnlimited {
return true
}
return h[i].txHistory < h[j].txHistory
}
func (h peerByTxHistory) Swap(i, j int) { h[i], h[j] = h[j], h[i] }
const (
maxTxStatusRetry = 3 // The maximum retrys will be made for tx status request.
maxTxStatusCandidates = 5 // The maximum les servers the tx status requests will be sent to.
)
// RetrieveTxStatus retrieves the transaction status from the LES network.
// There is no guarantee in the LES protocol that the mined transaction will
// be retrieved back for sure because of different reasons(the transaction
// is unindexed, the malicous server doesn't reply it deliberately, etc).
// Therefore, unretrieved transactions(UNKNOWN) will receive a certain number
// of retries, thus giving a weak guarantee.
func (odr *LesOdr) RetrieveTxStatus(ctx context.Context, req *light.TxStatusRequest) error {
// Sort according to the transaction history supported by the peer and
// select the peers with longest history.
var (
retries int
peers []*serverPeer
missing = len(req.Hashes)
result = make([]light.TxStatus, len(req.Hashes))
canSend = make(map[string]bool)
)
for _, peer := range odr.peers.allPeers() {
if peer.txHistory == txIndexDisabled {
continue
}
peers = append(peers, peer)
}
sort.Sort(sort.Reverse(peerByTxHistory(peers)))
for i := 0; i < maxTxStatusCandidates && i < len(peers); i++ {
canSend[peers[i].id] = true
}
// Send out the request and assemble the result.
for {
if retries >= maxTxStatusRetry || len(canSend) == 0 {
break
}
var (
// Deep copy the request, so that the partial result won't be mixed.
req = &TxStatusRequest{Hashes: req.Hashes}
id = rand.Uint64()
distreq = &distReq{
getCost: func(dp distPeer) uint64 { return req.GetCost(dp.(*serverPeer)) },
canSend: func(dp distPeer) bool { return canSend[dp.(*serverPeer).id] },
request: func(dp distPeer) func() {
p := dp.(*serverPeer)
p.fcServer.QueuedRequest(id, req.GetCost(p))
delete(canSend, p.id)
return func() { req.Request(id, p) }
},
}
)
if err := odr.retriever.retrieve(ctx, id, distreq, func(p distPeer, msg *Msg) error { return req.Validate(odr.db, msg) }, odr.stop); err != nil {
return err
}
// Collect the response and assemble them to the final result.
// All the response is not verifiable, so always pick the first
// one we get.
for index, status := range req.Status {
if result[index].Status != core.TxStatusUnknown {
continue
}
if status.Status == core.TxStatusUnknown {
continue
}
result[index], missing = status, missing-1
}
// Abort the procedure if all the status are retrieved
if missing == 0 {
break
}
retries += 1
}
req.Status = result
return nil
}
// Retrieve tries to fetch an object from the LES network. It's a common API
// for most of the LES requests except for the TxStatusRequest which needs
// the additional retry mechanism.
// If the network retrieval was successful, it stores the object in local db.
func (odr *LesOdr) Retrieve(ctx context.Context, req light.OdrRequest) (err error) {
lreq := LesRequest(req)
reqID := rand.Uint64()
rq := &distReq{
getCost: func(dp distPeer) uint64 {
return lreq.GetCost(dp.(*serverPeer))
},
canSend: func(dp distPeer) bool {
p := dp.(*serverPeer)
if !p.onlyAnnounce {
return lreq.CanSend(p)
}
return false
},
request: func(dp distPeer) func() {
p := dp.(*serverPeer)
cost := lreq.GetCost(p)
p.fcServer.QueuedRequest(reqID, cost)
return func() { lreq.Request(reqID, p) }
},
}
defer func(sent mclock.AbsTime) {
if err != nil {
return
}
requestRTT.Update(time.Duration(mclock.Now() - sent))
}(mclock.Now())
if err := odr.retriever.retrieve(ctx, reqID, rq, func(p distPeer, msg *Msg) error { return lreq.Validate(odr.db, msg) }, odr.stop); err != nil {
return err
}
req.StoreResult(odr.db)
return nil
}