plugeth/les/odr.go

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// Copyright 2016 The go-ethereum Authors
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// 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/>.
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package les
import (
"context"
"sort"
"time"
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"github.com/ethereum/go-ethereum/common/mclock"
"github.com/ethereum/go-ethereum/core"
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"github.com/ethereum/go-ethereum/ethdb"
"github.com/ethereum/go-ethereum/light"
)
// LesOdr implements light.OdrBackend
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type LesOdr struct {
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db ethdb.Database
indexerConfig *light.IndexerConfig
chtIndexer, bloomTrieIndexer, bloomIndexer *core.ChainIndexer
peers *serverPeerSet
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retriever *retrieveManager
stop chan struct{}
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}
func NewLesOdr(db ethdb.Database, config *light.IndexerConfig, peers *serverPeerSet, retriever *retrieveManager) *LesOdr {
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return &LesOdr{
db: db,
indexerConfig: config,
peers: peers,
retriever: retriever,
stop: make(chan struct{}),
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}
}
// Stop cancels all pending retrievals
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func (odr *LesOdr) Stop() {
close(odr.stop)
}
// Database returns the backing database
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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
}
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const (
MsgBlockHeaders = iota
MsgBlockBodies
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MsgCode
MsgReceipts
MsgProofsV2
MsgHelperTrieProofs
MsgTxStatus
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)
// 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 = genReqID()
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)
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reqID := genReqID()
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)
les, les/flowcontrol: improved request serving and flow control (#18230) This change - implements concurrent LES request serving even for a single peer. - replaces the request cost estimation method with a cost table based on benchmarks which gives much more consistent results. Until now the allowed number of light peers was just a guess which probably contributed a lot to the fluctuating quality of available service. Everything related to request cost is implemented in a single object, the 'cost tracker'. It uses a fixed cost table with a global 'correction factor'. Benchmark code is included and can be run at any time to adapt costs to low-level implementation changes. - reimplements flowcontrol.ClientManager in a cleaner and more efficient way, with added capabilities: There is now control over bandwidth, which allows using the flow control parameters for client prioritization. Target utilization over 100 percent is now supported to model concurrent request processing. Total serving bandwidth is reduced during block processing to prevent database contention. - implements an RPC API for the LES servers allowing server operators to assign priority bandwidth to certain clients and change prioritized status even while the client is connected. The new API is meant for cases where server operators charge for LES using an off-protocol mechanism. - adds a unit test for the new client manager. - adds an end-to-end test using the network simulator that tests bandwidth control functions through the new API.
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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
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}
req.StoreResult(odr.db)
return nil
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}