8b57c49490
Reworked the EVM gas instructions to use 64bit integers rather than arbitrary size big ints. All gas operations, be it additions, multiplications or divisions, are checked and guarded against 64 bit integer overflows. In additon, most of the protocol paramaters in the params package have been converted to uint64 and are now constants rather than variables. * common/math: added overflow check ops * core: vmenv, env renamed to evm * eth, internal/ethapi, les: unmetered eth_call and cancel methods * core/vm: implemented big.Int pool for evm instructions * core/vm: unexported intPool methods & verification methods * core/vm: added memoryGasCost overflow check and test
1530 lines
60 KiB
Go
1530 lines
60 KiB
Go
// 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 downloader contains the manual full chain synchronisation.
|
|
package downloader
|
|
|
|
import (
|
|
"crypto/rand"
|
|
"errors"
|
|
"fmt"
|
|
"math"
|
|
"math/big"
|
|
"strings"
|
|
"sync"
|
|
"sync/atomic"
|
|
"time"
|
|
|
|
ethereum "github.com/ethereum/go-ethereum"
|
|
"github.com/ethereum/go-ethereum/common"
|
|
"github.com/ethereum/go-ethereum/core/types"
|
|
"github.com/ethereum/go-ethereum/ethdb"
|
|
"github.com/ethereum/go-ethereum/event"
|
|
"github.com/ethereum/go-ethereum/logger"
|
|
"github.com/ethereum/go-ethereum/logger/glog"
|
|
"github.com/ethereum/go-ethereum/params"
|
|
"github.com/ethereum/go-ethereum/trie"
|
|
"github.com/rcrowley/go-metrics"
|
|
)
|
|
|
|
var (
|
|
MaxHashFetch = 512 // Amount of hashes to be fetched per retrieval request
|
|
MaxBlockFetch = 128 // Amount of blocks to be fetched per retrieval request
|
|
MaxHeaderFetch = 192 // Amount of block headers to be fetched per retrieval request
|
|
MaxSkeletonSize = 128 // Number of header fetches to need for a skeleton assembly
|
|
MaxBodyFetch = 128 // Amount of block bodies to be fetched per retrieval request
|
|
MaxReceiptFetch = 256 // Amount of transaction receipts to allow fetching per request
|
|
MaxStateFetch = 384 // Amount of node state values to allow fetching per request
|
|
|
|
MaxForkAncestry = 3 * params.EpochDuration // Maximum chain reorganisation
|
|
rttMinEstimate = 2 * time.Second // Minimum round-trip time to target for download requests
|
|
rttMaxEstimate = 20 * time.Second // Maximum rount-trip time to target for download requests
|
|
rttMinConfidence = 0.1 // Worse confidence factor in our estimated RTT value
|
|
ttlScaling = 3 // Constant scaling factor for RTT -> TTL conversion
|
|
ttlLimit = time.Minute // Maximum TTL allowance to prevent reaching crazy timeouts
|
|
|
|
qosTuningPeers = 5 // Number of peers to tune based on (best peers)
|
|
qosConfidenceCap = 10 // Number of peers above which not to modify RTT confidence
|
|
qosTuningImpact = 0.25 // Impact that a new tuning target has on the previous value
|
|
|
|
maxQueuedHeaders = 32 * 1024 // [eth/62] Maximum number of headers to queue for import (DOS protection)
|
|
maxHeadersProcess = 2048 // Number of header download results to import at once into the chain
|
|
maxResultsProcess = 2048 // Number of content download results to import at once into the chain
|
|
|
|
fsHeaderCheckFrequency = 100 // Verification frequency of the downloaded headers during fast sync
|
|
fsHeaderSafetyNet = 2048 // Number of headers to discard in case a chain violation is detected
|
|
fsHeaderForceVerify = 24 // Number of headers to verify before and after the pivot to accept it
|
|
fsPivotInterval = 256 // Number of headers out of which to randomize the pivot point
|
|
fsMinFullBlocks = 64 // Number of blocks to retrieve fully even in fast sync
|
|
fsCriticalTrials = uint32(32) // Number of times to retry in the cricical section before bailing
|
|
)
|
|
|
|
var (
|
|
errBusy = errors.New("busy")
|
|
errUnknownPeer = errors.New("peer is unknown or unhealthy")
|
|
errBadPeer = errors.New("action from bad peer ignored")
|
|
errStallingPeer = errors.New("peer is stalling")
|
|
errNoPeers = errors.New("no peers to keep download active")
|
|
errTimeout = errors.New("timeout")
|
|
errEmptyHeaderSet = errors.New("empty header set by peer")
|
|
errPeersUnavailable = errors.New("no peers available or all tried for download")
|
|
errInvalidAncestor = errors.New("retrieved ancestor is invalid")
|
|
errInvalidChain = errors.New("retrieved hash chain is invalid")
|
|
errInvalidBlock = errors.New("retrieved block is invalid")
|
|
errInvalidBody = errors.New("retrieved block body is invalid")
|
|
errInvalidReceipt = errors.New("retrieved receipt is invalid")
|
|
errCancelBlockFetch = errors.New("block download canceled (requested)")
|
|
errCancelHeaderFetch = errors.New("block header download canceled (requested)")
|
|
errCancelBodyFetch = errors.New("block body download canceled (requested)")
|
|
errCancelReceiptFetch = errors.New("receipt download canceled (requested)")
|
|
errCancelStateFetch = errors.New("state data download canceled (requested)")
|
|
errCancelHeaderProcessing = errors.New("header processing canceled (requested)")
|
|
errCancelContentProcessing = errors.New("content processing canceled (requested)")
|
|
errNoSyncActive = errors.New("no sync active")
|
|
errTooOld = errors.New("peer doesn't speak recent enough protocol version (need version >= 62)")
|
|
)
|
|
|
|
type Downloader struct {
|
|
mode SyncMode // Synchronisation mode defining the strategy used (per sync cycle)
|
|
mux *event.TypeMux // Event multiplexer to announce sync operation events
|
|
|
|
queue *queue // Scheduler for selecting the hashes to download
|
|
peers *peerSet // Set of active peers from which download can proceed
|
|
|
|
fsPivotLock *types.Header // Pivot header on critical section entry (cannot change between retries)
|
|
fsPivotFails uint32 // Number of subsequent fast sync failures in the critical section
|
|
|
|
rttEstimate uint64 // Round trip time to target for download requests
|
|
rttConfidence uint64 // Confidence in the estimated RTT (unit: millionths to allow atomic ops)
|
|
|
|
// Statistics
|
|
syncStatsChainOrigin uint64 // Origin block number where syncing started at
|
|
syncStatsChainHeight uint64 // Highest block number known when syncing started
|
|
syncStatsStateDone uint64 // Number of state trie entries already pulled
|
|
syncStatsLock sync.RWMutex // Lock protecting the sync stats fields
|
|
|
|
// Callbacks
|
|
hasHeader headerCheckFn // Checks if a header is present in the chain
|
|
hasBlockAndState blockAndStateCheckFn // Checks if a block and associated state is present in the chain
|
|
getHeader headerRetrievalFn // Retrieves a header from the chain
|
|
getBlock blockRetrievalFn // Retrieves a block from the chain
|
|
headHeader headHeaderRetrievalFn // Retrieves the head header from the chain
|
|
headBlock headBlockRetrievalFn // Retrieves the head block from the chain
|
|
headFastBlock headFastBlockRetrievalFn // Retrieves the head fast-sync block from the chain
|
|
commitHeadBlock headBlockCommitterFn // Commits a manually assembled block as the chain head
|
|
getTd tdRetrievalFn // Retrieves the TD of a block from the chain
|
|
insertHeaders headerChainInsertFn // Injects a batch of headers into the chain
|
|
insertBlocks blockChainInsertFn // Injects a batch of blocks into the chain
|
|
insertReceipts receiptChainInsertFn // Injects a batch of blocks and their receipts into the chain
|
|
rollback chainRollbackFn // Removes a batch of recently added chain links
|
|
dropPeer peerDropFn // Drops a peer for misbehaving
|
|
|
|
// Status
|
|
synchroniseMock func(id string, hash common.Hash) error // Replacement for synchronise during testing
|
|
synchronising int32
|
|
notified int32
|
|
|
|
// Channels
|
|
newPeerCh chan *peer
|
|
headerCh chan dataPack // [eth/62] Channel receiving inbound block headers
|
|
bodyCh chan dataPack // [eth/62] Channel receiving inbound block bodies
|
|
receiptCh chan dataPack // [eth/63] Channel receiving inbound receipts
|
|
stateCh chan dataPack // [eth/63] Channel receiving inbound node state data
|
|
bodyWakeCh chan bool // [eth/62] Channel to signal the block body fetcher of new tasks
|
|
receiptWakeCh chan bool // [eth/63] Channel to signal the receipt fetcher of new tasks
|
|
stateWakeCh chan bool // [eth/63] Channel to signal the state fetcher of new tasks
|
|
headerProcCh chan []*types.Header // [eth/62] Channel to feed the header processor new tasks
|
|
|
|
// Cancellation and termination
|
|
cancelPeer string // Identifier of the peer currently being used as the master (cancel on drop)
|
|
cancelCh chan struct{} // Channel to cancel mid-flight syncs
|
|
cancelLock sync.RWMutex // Lock to protect the cancel channel and peer in delivers
|
|
|
|
quitCh chan struct{} // Quit channel to signal termination
|
|
quitLock sync.RWMutex // Lock to prevent double closes
|
|
|
|
// Testing hooks
|
|
syncInitHook func(uint64, uint64) // Method to call upon initiating a new sync run
|
|
bodyFetchHook func([]*types.Header) // Method to call upon starting a block body fetch
|
|
receiptFetchHook func([]*types.Header) // Method to call upon starting a receipt fetch
|
|
chainInsertHook func([]*fetchResult) // Method to call upon inserting a chain of blocks (possibly in multiple invocations)
|
|
}
|
|
|
|
// New creates a new downloader to fetch hashes and blocks from remote peers.
|
|
func New(mode SyncMode, stateDb ethdb.Database, mux *event.TypeMux, hasHeader headerCheckFn, hasBlockAndState blockAndStateCheckFn,
|
|
getHeader headerRetrievalFn, getBlock blockRetrievalFn, headHeader headHeaderRetrievalFn, headBlock headBlockRetrievalFn,
|
|
headFastBlock headFastBlockRetrievalFn, commitHeadBlock headBlockCommitterFn, getTd tdRetrievalFn, insertHeaders headerChainInsertFn,
|
|
insertBlocks blockChainInsertFn, insertReceipts receiptChainInsertFn, rollback chainRollbackFn, dropPeer peerDropFn) *Downloader {
|
|
|
|
dl := &Downloader{
|
|
mode: mode,
|
|
mux: mux,
|
|
queue: newQueue(stateDb),
|
|
peers: newPeerSet(),
|
|
rttEstimate: uint64(rttMaxEstimate),
|
|
rttConfidence: uint64(1000000),
|
|
hasHeader: hasHeader,
|
|
hasBlockAndState: hasBlockAndState,
|
|
getHeader: getHeader,
|
|
getBlock: getBlock,
|
|
headHeader: headHeader,
|
|
headBlock: headBlock,
|
|
headFastBlock: headFastBlock,
|
|
commitHeadBlock: commitHeadBlock,
|
|
getTd: getTd,
|
|
insertHeaders: insertHeaders,
|
|
insertBlocks: insertBlocks,
|
|
insertReceipts: insertReceipts,
|
|
rollback: rollback,
|
|
dropPeer: dropPeer,
|
|
newPeerCh: make(chan *peer, 1),
|
|
headerCh: make(chan dataPack, 1),
|
|
bodyCh: make(chan dataPack, 1),
|
|
receiptCh: make(chan dataPack, 1),
|
|
stateCh: make(chan dataPack, 1),
|
|
bodyWakeCh: make(chan bool, 1),
|
|
receiptWakeCh: make(chan bool, 1),
|
|
stateWakeCh: make(chan bool, 1),
|
|
headerProcCh: make(chan []*types.Header, 1),
|
|
quitCh: make(chan struct{}),
|
|
}
|
|
go dl.qosTuner()
|
|
return dl
|
|
}
|
|
|
|
// Progress retrieves the synchronisation boundaries, specifically the origin
|
|
// block where synchronisation started at (may have failed/suspended); the block
|
|
// or header sync is currently at; and the latest known block which the sync targets.
|
|
//
|
|
// In addition, during the state download phase of fast synchronisation the number
|
|
// of processed and the total number of known states are also returned. Otherwise
|
|
// these are zero.
|
|
func (d *Downloader) Progress() ethereum.SyncProgress {
|
|
// Fetch the pending state count outside of the lock to prevent unforeseen deadlocks
|
|
pendingStates := uint64(d.queue.PendingNodeData())
|
|
|
|
// Lock the current stats and return the progress
|
|
d.syncStatsLock.RLock()
|
|
defer d.syncStatsLock.RUnlock()
|
|
|
|
current := uint64(0)
|
|
switch d.mode {
|
|
case FullSync:
|
|
current = d.headBlock().NumberU64()
|
|
case FastSync:
|
|
current = d.headFastBlock().NumberU64()
|
|
case LightSync:
|
|
current = d.headHeader().Number.Uint64()
|
|
}
|
|
return ethereum.SyncProgress{
|
|
StartingBlock: d.syncStatsChainOrigin,
|
|
CurrentBlock: current,
|
|
HighestBlock: d.syncStatsChainHeight,
|
|
PulledStates: d.syncStatsStateDone,
|
|
KnownStates: d.syncStatsStateDone + pendingStates,
|
|
}
|
|
}
|
|
|
|
// Synchronising returns whether the downloader is currently retrieving blocks.
|
|
func (d *Downloader) Synchronising() bool {
|
|
return atomic.LoadInt32(&d.synchronising) > 0
|
|
}
|
|
|
|
// RegisterPeer injects a new download peer into the set of block source to be
|
|
// used for fetching hashes and blocks from.
|
|
func (d *Downloader) RegisterPeer(id string, version int, currentHead currentHeadRetrievalFn,
|
|
getRelHeaders relativeHeaderFetcherFn, getAbsHeaders absoluteHeaderFetcherFn, getBlockBodies blockBodyFetcherFn,
|
|
getReceipts receiptFetcherFn, getNodeData stateFetcherFn) error {
|
|
|
|
glog.V(logger.Detail).Infoln("Registering peer", id)
|
|
if err := d.peers.Register(newPeer(id, version, currentHead, getRelHeaders, getAbsHeaders, getBlockBodies, getReceipts, getNodeData)); err != nil {
|
|
glog.V(logger.Error).Infoln("Register failed:", err)
|
|
return err
|
|
}
|
|
d.qosReduceConfidence()
|
|
|
|
return nil
|
|
}
|
|
|
|
// UnregisterPeer remove a peer from the known list, preventing any action from
|
|
// the specified peer. An effort is also made to return any pending fetches into
|
|
// the queue.
|
|
func (d *Downloader) UnregisterPeer(id string) error {
|
|
// Unregister the peer from the active peer set and revoke any fetch tasks
|
|
glog.V(logger.Detail).Infoln("Unregistering peer", id)
|
|
if err := d.peers.Unregister(id); err != nil {
|
|
glog.V(logger.Error).Infoln("Unregister failed:", err)
|
|
return err
|
|
}
|
|
d.queue.Revoke(id)
|
|
|
|
// If this peer was the master peer, abort sync immediately
|
|
d.cancelLock.RLock()
|
|
master := id == d.cancelPeer
|
|
d.cancelLock.RUnlock()
|
|
|
|
if master {
|
|
d.cancel()
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// Synchronise tries to sync up our local block chain with a remote peer, both
|
|
// adding various sanity checks as well as wrapping it with various log entries.
|
|
func (d *Downloader) Synchronise(id string, head common.Hash, td *big.Int, mode SyncMode) error {
|
|
glog.V(logger.Detail).Infof("Attempting synchronisation: %v, head [%x…], TD %v", id, head[:4], td)
|
|
|
|
err := d.synchronise(id, head, td, mode)
|
|
switch err {
|
|
case nil:
|
|
glog.V(logger.Detail).Infof("Synchronisation completed")
|
|
|
|
case errBusy:
|
|
glog.V(logger.Detail).Infof("Synchronisation already in progress")
|
|
|
|
case errTimeout, errBadPeer, errStallingPeer,
|
|
errEmptyHeaderSet, errPeersUnavailable, errTooOld,
|
|
errInvalidAncestor, errInvalidChain:
|
|
glog.V(logger.Debug).Infof("Removing peer %v: %v", id, err)
|
|
d.dropPeer(id)
|
|
|
|
default:
|
|
glog.V(logger.Warn).Infof("Synchronisation failed: %v", err)
|
|
}
|
|
return err
|
|
}
|
|
|
|
// synchronise will select the peer and use it for synchronising. If an empty string is given
|
|
// it will use the best peer possible and synchronize if it's TD is higher than our own. If any of the
|
|
// checks fail an error will be returned. This method is synchronous
|
|
func (d *Downloader) synchronise(id string, hash common.Hash, td *big.Int, mode SyncMode) error {
|
|
// Mock out the synchronisation if testing
|
|
if d.synchroniseMock != nil {
|
|
return d.synchroniseMock(id, hash)
|
|
}
|
|
// Make sure only one goroutine is ever allowed past this point at once
|
|
if !atomic.CompareAndSwapInt32(&d.synchronising, 0, 1) {
|
|
return errBusy
|
|
}
|
|
defer atomic.StoreInt32(&d.synchronising, 0)
|
|
|
|
// Post a user notification of the sync (only once per session)
|
|
if atomic.CompareAndSwapInt32(&d.notified, 0, 1) {
|
|
glog.V(logger.Info).Infoln("Block synchronisation started")
|
|
}
|
|
// Reset the queue, peer set and wake channels to clean any internal leftover state
|
|
d.queue.Reset()
|
|
d.peers.Reset()
|
|
|
|
for _, ch := range []chan bool{d.bodyWakeCh, d.receiptWakeCh, d.stateWakeCh} {
|
|
select {
|
|
case <-ch:
|
|
default:
|
|
}
|
|
}
|
|
for _, ch := range []chan dataPack{d.headerCh, d.bodyCh, d.receiptCh, d.stateCh} {
|
|
for empty := false; !empty; {
|
|
select {
|
|
case <-ch:
|
|
default:
|
|
empty = true
|
|
}
|
|
}
|
|
}
|
|
for empty := false; !empty; {
|
|
select {
|
|
case <-d.headerProcCh:
|
|
default:
|
|
empty = true
|
|
}
|
|
}
|
|
// Create cancel channel for aborting mid-flight and mark the master peer
|
|
d.cancelLock.Lock()
|
|
d.cancelCh = make(chan struct{})
|
|
d.cancelPeer = id
|
|
d.cancelLock.Unlock()
|
|
|
|
defer d.cancel() // No matter what, we can't leave the cancel channel open
|
|
|
|
// Set the requested sync mode, unless it's forbidden
|
|
d.mode = mode
|
|
if d.mode == FastSync && atomic.LoadUint32(&d.fsPivotFails) >= fsCriticalTrials {
|
|
d.mode = FullSync
|
|
}
|
|
// Retrieve the origin peer and initiate the downloading process
|
|
p := d.peers.Peer(id)
|
|
if p == nil {
|
|
return errUnknownPeer
|
|
}
|
|
return d.syncWithPeer(p, hash, td)
|
|
}
|
|
|
|
// syncWithPeer starts a block synchronization based on the hash chain from the
|
|
// specified peer and head hash.
|
|
func (d *Downloader) syncWithPeer(p *peer, hash common.Hash, td *big.Int) (err error) {
|
|
d.mux.Post(StartEvent{})
|
|
defer func() {
|
|
// reset on error
|
|
if err != nil {
|
|
d.mux.Post(FailedEvent{err})
|
|
} else {
|
|
d.mux.Post(DoneEvent{})
|
|
}
|
|
}()
|
|
if p.version < 62 {
|
|
return errTooOld
|
|
}
|
|
|
|
glog.V(logger.Debug).Infof("Synchronising with the network using: %s [eth/%d]", p.id, p.version)
|
|
defer func(start time.Time) {
|
|
glog.V(logger.Debug).Infof("Synchronisation terminated after %v", time.Since(start))
|
|
}(time.Now())
|
|
|
|
// Look up the sync boundaries: the common ancestor and the target block
|
|
latest, err := d.fetchHeight(p)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
height := latest.Number.Uint64()
|
|
|
|
origin, err := d.findAncestor(p, height)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
d.syncStatsLock.Lock()
|
|
if d.syncStatsChainHeight <= origin || d.syncStatsChainOrigin > origin {
|
|
d.syncStatsChainOrigin = origin
|
|
}
|
|
d.syncStatsChainHeight = height
|
|
d.syncStatsLock.Unlock()
|
|
|
|
// Initiate the sync using a concurrent header and content retrieval algorithm
|
|
pivot := uint64(0)
|
|
switch d.mode {
|
|
case LightSync:
|
|
pivot = height
|
|
case FastSync:
|
|
// Calculate the new fast/slow sync pivot point
|
|
if d.fsPivotLock == nil {
|
|
pivotOffset, err := rand.Int(rand.Reader, big.NewInt(int64(fsPivotInterval)))
|
|
if err != nil {
|
|
panic(fmt.Sprintf("Failed to access crypto random source: %v", err))
|
|
}
|
|
if height > uint64(fsMinFullBlocks)+pivotOffset.Uint64() {
|
|
pivot = height - uint64(fsMinFullBlocks) - pivotOffset.Uint64()
|
|
}
|
|
} else {
|
|
// Pivot point locked in, use this and do not pick a new one!
|
|
pivot = d.fsPivotLock.Number.Uint64()
|
|
}
|
|
// If the point is below the origin, move origin back to ensure state download
|
|
if pivot < origin {
|
|
if pivot > 0 {
|
|
origin = pivot - 1
|
|
} else {
|
|
origin = 0
|
|
}
|
|
}
|
|
glog.V(logger.Debug).Infof("Fast syncing until pivot block #%d", pivot)
|
|
}
|
|
d.queue.Prepare(origin+1, d.mode, pivot, latest)
|
|
if d.syncInitHook != nil {
|
|
d.syncInitHook(origin, height)
|
|
}
|
|
return d.spawnSync(origin+1,
|
|
func() error { return d.fetchHeaders(p, origin+1) }, // Headers are always retrieved
|
|
func() error { return d.processHeaders(origin+1, td) }, // Headers are always retrieved
|
|
func() error { return d.fetchBodies(origin + 1) }, // Bodies are retrieved during normal and fast sync
|
|
func() error { return d.fetchReceipts(origin + 1) }, // Receipts are retrieved during fast sync
|
|
func() error { return d.fetchNodeData() }, // Node state data is retrieved during fast sync
|
|
)
|
|
}
|
|
|
|
// spawnSync runs d.process and all given fetcher functions to completion in
|
|
// separate goroutines, returning the first error that appears.
|
|
func (d *Downloader) spawnSync(origin uint64, fetchers ...func() error) error {
|
|
var wg sync.WaitGroup
|
|
errc := make(chan error, len(fetchers)+1)
|
|
wg.Add(len(fetchers) + 1)
|
|
go func() { defer wg.Done(); errc <- d.processContent() }()
|
|
for _, fn := range fetchers {
|
|
fn := fn
|
|
go func() { defer wg.Done(); errc <- fn() }()
|
|
}
|
|
// Wait for the first error, then terminate the others.
|
|
var err error
|
|
for i := 0; i < len(fetchers)+1; i++ {
|
|
if i == len(fetchers) {
|
|
// Close the queue when all fetchers have exited.
|
|
// This will cause the block processor to end when
|
|
// it has processed the queue.
|
|
d.queue.Close()
|
|
}
|
|
if err = <-errc; err != nil {
|
|
break
|
|
}
|
|
}
|
|
d.queue.Close()
|
|
d.cancel()
|
|
wg.Wait()
|
|
|
|
// If sync failed in the critical section, bump the fail counter
|
|
if err != nil && d.mode == FastSync && d.fsPivotLock != nil {
|
|
atomic.AddUint32(&d.fsPivotFails, 1)
|
|
}
|
|
return err
|
|
}
|
|
|
|
// cancel cancels all of the operations and resets the queue. It returns true
|
|
// if the cancel operation was completed.
|
|
func (d *Downloader) cancel() {
|
|
// Close the current cancel channel
|
|
d.cancelLock.Lock()
|
|
if d.cancelCh != nil {
|
|
select {
|
|
case <-d.cancelCh:
|
|
// Channel was already closed
|
|
default:
|
|
close(d.cancelCh)
|
|
}
|
|
}
|
|
d.cancelLock.Unlock()
|
|
}
|
|
|
|
// Terminate interrupts the downloader, canceling all pending operations.
|
|
// The downloader cannot be reused after calling Terminate.
|
|
func (d *Downloader) Terminate() {
|
|
// Close the termination channel (make sure double close is allowed)
|
|
d.quitLock.Lock()
|
|
select {
|
|
case <-d.quitCh:
|
|
default:
|
|
close(d.quitCh)
|
|
}
|
|
d.quitLock.Unlock()
|
|
|
|
// Cancel any pending download requests
|
|
d.cancel()
|
|
}
|
|
|
|
// fetchHeight retrieves the head header of the remote peer to aid in estimating
|
|
// the total time a pending synchronisation would take.
|
|
func (d *Downloader) fetchHeight(p *peer) (*types.Header, error) {
|
|
glog.V(logger.Debug).Infof("%v: retrieving remote chain height", p)
|
|
|
|
// Request the advertised remote head block and wait for the response
|
|
head, _ := p.currentHead()
|
|
go p.getRelHeaders(head, 1, 0, false)
|
|
|
|
timeout := time.After(d.requestTTL())
|
|
for {
|
|
select {
|
|
case <-d.cancelCh:
|
|
return nil, errCancelBlockFetch
|
|
|
|
case packet := <-d.headerCh:
|
|
// Discard anything not from the origin peer
|
|
if packet.PeerId() != p.id {
|
|
glog.V(logger.Debug).Infof("Received headers from incorrect peer(%s)", packet.PeerId())
|
|
break
|
|
}
|
|
// Make sure the peer actually gave something valid
|
|
headers := packet.(*headerPack).headers
|
|
if len(headers) != 1 {
|
|
glog.V(logger.Debug).Infof("%v: invalid number of head headers: %d != 1", p, len(headers))
|
|
return nil, errBadPeer
|
|
}
|
|
return headers[0], nil
|
|
|
|
case <-timeout:
|
|
glog.V(logger.Debug).Infof("%v: head header timeout", p)
|
|
return nil, errTimeout
|
|
|
|
case <-d.bodyCh:
|
|
case <-d.stateCh:
|
|
case <-d.receiptCh:
|
|
// Out of bounds delivery, ignore
|
|
}
|
|
}
|
|
}
|
|
|
|
// findAncestor tries to locate the common ancestor link of the local chain and
|
|
// a remote peers blockchain. In the general case when our node was in sync and
|
|
// on the correct chain, checking the top N links should already get us a match.
|
|
// In the rare scenario when we ended up on a long reorganisation (i.e. none of
|
|
// the head links match), we do a binary search to find the common ancestor.
|
|
func (d *Downloader) findAncestor(p *peer, height uint64) (uint64, error) {
|
|
glog.V(logger.Debug).Infof("%v: looking for common ancestor (remote height %d)", p, height)
|
|
|
|
// Figure out the valid ancestor range to prevent rewrite attacks
|
|
floor, ceil := int64(-1), d.headHeader().Number.Uint64()
|
|
if d.mode == FullSync {
|
|
ceil = d.headBlock().NumberU64()
|
|
} else if d.mode == FastSync {
|
|
ceil = d.headFastBlock().NumberU64()
|
|
}
|
|
if ceil >= MaxForkAncestry {
|
|
floor = int64(ceil - MaxForkAncestry)
|
|
}
|
|
// Request the topmost blocks to short circuit binary ancestor lookup
|
|
head := ceil
|
|
if head > height {
|
|
head = height
|
|
}
|
|
from := int64(head) - int64(MaxHeaderFetch)
|
|
if from < 0 {
|
|
from = 0
|
|
}
|
|
// Span out with 15 block gaps into the future to catch bad head reports
|
|
limit := 2 * MaxHeaderFetch / 16
|
|
count := 1 + int((int64(ceil)-from)/16)
|
|
if count > limit {
|
|
count = limit
|
|
}
|
|
go p.getAbsHeaders(uint64(from), count, 15, false)
|
|
|
|
// Wait for the remote response to the head fetch
|
|
number, hash := uint64(0), common.Hash{}
|
|
timeout := time.After(d.requestTTL())
|
|
|
|
for finished := false; !finished; {
|
|
select {
|
|
case <-d.cancelCh:
|
|
return 0, errCancelHeaderFetch
|
|
|
|
case packet := <-d.headerCh:
|
|
// Discard anything not from the origin peer
|
|
if packet.PeerId() != p.id {
|
|
glog.V(logger.Debug).Infof("Received headers from incorrect peer(%s)", packet.PeerId())
|
|
break
|
|
}
|
|
// Make sure the peer actually gave something valid
|
|
headers := packet.(*headerPack).headers
|
|
if len(headers) == 0 {
|
|
glog.V(logger.Warn).Infof("%v: empty head header set", p)
|
|
return 0, errEmptyHeaderSet
|
|
}
|
|
// Make sure the peer's reply conforms to the request
|
|
for i := 0; i < len(headers); i++ {
|
|
if number := headers[i].Number.Int64(); number != from+int64(i)*16 {
|
|
glog.V(logger.Warn).Infof("%v: head header set (item %d) broke chain ordering: requested %d, got %d", p, i, from+int64(i)*16, number)
|
|
return 0, errInvalidChain
|
|
}
|
|
}
|
|
// Check if a common ancestor was found
|
|
finished = true
|
|
for i := len(headers) - 1; i >= 0; i-- {
|
|
// Skip any headers that underflow/overflow our requested set
|
|
if headers[i].Number.Int64() < from || headers[i].Number.Uint64() > ceil {
|
|
continue
|
|
}
|
|
// Otherwise check if we already know the header or not
|
|
if (d.mode == FullSync && d.hasBlockAndState(headers[i].Hash())) || (d.mode != FullSync && d.hasHeader(headers[i].Hash())) {
|
|
number, hash = headers[i].Number.Uint64(), headers[i].Hash()
|
|
|
|
// If every header is known, even future ones, the peer straight out lied about its head
|
|
if number > height && i == limit-1 {
|
|
glog.V(logger.Warn).Infof("%v: lied about chain head: reported %d, found above %d", p, height, number)
|
|
return 0, errStallingPeer
|
|
}
|
|
break
|
|
}
|
|
}
|
|
|
|
case <-timeout:
|
|
glog.V(logger.Debug).Infof("%v: head header timeout", p)
|
|
return 0, errTimeout
|
|
|
|
case <-d.bodyCh:
|
|
case <-d.stateCh:
|
|
case <-d.receiptCh:
|
|
// Out of bounds delivery, ignore
|
|
}
|
|
}
|
|
// If the head fetch already found an ancestor, return
|
|
if !common.EmptyHash(hash) {
|
|
if int64(number) <= floor {
|
|
glog.V(logger.Warn).Infof("%v: potential rewrite attack: #%d [%x…] <= #%d limit", p, number, hash[:4], floor)
|
|
return 0, errInvalidAncestor
|
|
}
|
|
glog.V(logger.Debug).Infof("%v: common ancestor: #%d [%x…]", p, number, hash[:4])
|
|
return number, nil
|
|
}
|
|
// Ancestor not found, we need to binary search over our chain
|
|
start, end := uint64(0), head
|
|
if floor > 0 {
|
|
start = uint64(floor)
|
|
}
|
|
for start+1 < end {
|
|
// Split our chain interval in two, and request the hash to cross check
|
|
check := (start + end) / 2
|
|
|
|
timeout := time.After(d.requestTTL())
|
|
go p.getAbsHeaders(uint64(check), 1, 0, false)
|
|
|
|
// Wait until a reply arrives to this request
|
|
for arrived := false; !arrived; {
|
|
select {
|
|
case <-d.cancelCh:
|
|
return 0, errCancelHeaderFetch
|
|
|
|
case packer := <-d.headerCh:
|
|
// Discard anything not from the origin peer
|
|
if packer.PeerId() != p.id {
|
|
glog.V(logger.Debug).Infof("Received headers from incorrect peer(%s)", packer.PeerId())
|
|
break
|
|
}
|
|
// Make sure the peer actually gave something valid
|
|
headers := packer.(*headerPack).headers
|
|
if len(headers) != 1 {
|
|
glog.V(logger.Debug).Infof("%v: invalid search header set (%d)", p, len(headers))
|
|
return 0, errBadPeer
|
|
}
|
|
arrived = true
|
|
|
|
// Modify the search interval based on the response
|
|
if (d.mode == FullSync && !d.hasBlockAndState(headers[0].Hash())) || (d.mode != FullSync && !d.hasHeader(headers[0].Hash())) {
|
|
end = check
|
|
break
|
|
}
|
|
header := d.getHeader(headers[0].Hash()) // Independent of sync mode, header surely exists
|
|
if header.Number.Uint64() != check {
|
|
glog.V(logger.Debug).Infof("%v: non requested header #%d [%x…], instead of #%d", p, header.Number, header.Hash().Bytes()[:4], check)
|
|
return 0, errBadPeer
|
|
}
|
|
start = check
|
|
|
|
case <-timeout:
|
|
glog.V(logger.Debug).Infof("%v: search header timeout", p)
|
|
return 0, errTimeout
|
|
|
|
case <-d.bodyCh:
|
|
case <-d.stateCh:
|
|
case <-d.receiptCh:
|
|
// Out of bounds delivery, ignore
|
|
}
|
|
}
|
|
}
|
|
// Ensure valid ancestry and return
|
|
if int64(start) <= floor {
|
|
glog.V(logger.Warn).Infof("%v: potential rewrite attack: #%d [%x…] <= #%d limit", p, start, hash[:4], floor)
|
|
return 0, errInvalidAncestor
|
|
}
|
|
glog.V(logger.Debug).Infof("%v: common ancestor: #%d [%x…]", p, start, hash[:4])
|
|
return start, nil
|
|
}
|
|
|
|
// fetchHeaders keeps retrieving headers concurrently from the number
|
|
// requested, until no more are returned, potentially throttling on the way. To
|
|
// facilitate concurrency but still protect against malicious nodes sending bad
|
|
// headers, we construct a header chain skeleton using the "origin" peer we are
|
|
// syncing with, and fill in the missing headers using anyone else. Headers from
|
|
// other peers are only accepted if they map cleanly to the skeleton. If no one
|
|
// can fill in the skeleton - not even the origin peer - it's assumed invalid and
|
|
// the origin is dropped.
|
|
func (d *Downloader) fetchHeaders(p *peer, from uint64) error {
|
|
glog.V(logger.Debug).Infof("%v: directing header downloads from #%d", p, from)
|
|
defer glog.V(logger.Debug).Infof("%v: header download terminated", p)
|
|
|
|
// Create a timeout timer, and the associated header fetcher
|
|
skeleton := true // Skeleton assembly phase or finishing up
|
|
request := time.Now() // time of the last skeleton fetch request
|
|
timeout := time.NewTimer(0) // timer to dump a non-responsive active peer
|
|
<-timeout.C // timeout channel should be initially empty
|
|
defer timeout.Stop()
|
|
|
|
getHeaders := func(from uint64) {
|
|
request = time.Now()
|
|
timeout.Reset(d.requestTTL())
|
|
|
|
if skeleton {
|
|
glog.V(logger.Detail).Infof("%v: fetching %d skeleton headers from #%d", p, MaxHeaderFetch, from)
|
|
go p.getAbsHeaders(from+uint64(MaxHeaderFetch)-1, MaxSkeletonSize, MaxHeaderFetch-1, false)
|
|
} else {
|
|
glog.V(logger.Detail).Infof("%v: fetching %d full headers from #%d", p, MaxHeaderFetch, from)
|
|
go p.getAbsHeaders(from, MaxHeaderFetch, 0, false)
|
|
}
|
|
}
|
|
// Start pulling the header chain skeleton until all is done
|
|
getHeaders(from)
|
|
|
|
for {
|
|
select {
|
|
case <-d.cancelCh:
|
|
return errCancelHeaderFetch
|
|
|
|
case packet := <-d.headerCh:
|
|
// Make sure the active peer is giving us the skeleton headers
|
|
if packet.PeerId() != p.id {
|
|
glog.V(logger.Debug).Infof("Received skeleton headers from incorrect peer (%s)", packet.PeerId())
|
|
break
|
|
}
|
|
headerReqTimer.UpdateSince(request)
|
|
timeout.Stop()
|
|
|
|
// If the skeleton's finished, pull any remaining head headers directly from the origin
|
|
if packet.Items() == 0 && skeleton {
|
|
skeleton = false
|
|
getHeaders(from)
|
|
continue
|
|
}
|
|
// If no more headers are inbound, notify the content fetchers and return
|
|
if packet.Items() == 0 {
|
|
glog.V(logger.Debug).Infof("%v: no available headers", p)
|
|
select {
|
|
case d.headerProcCh <- nil:
|
|
return nil
|
|
case <-d.cancelCh:
|
|
return errCancelHeaderFetch
|
|
}
|
|
}
|
|
headers := packet.(*headerPack).headers
|
|
|
|
// If we received a skeleton batch, resolve internals concurrently
|
|
if skeleton {
|
|
filled, proced, err := d.fillHeaderSkeleton(from, headers)
|
|
if err != nil {
|
|
glog.V(logger.Debug).Infof("%v: skeleton chain invalid: %v", p, err)
|
|
return errInvalidChain
|
|
}
|
|
headers = filled[proced:]
|
|
from += uint64(proced)
|
|
}
|
|
// Insert all the new headers and fetch the next batch
|
|
if len(headers) > 0 {
|
|
glog.V(logger.Detail).Infof("%v: schedule %d headers from #%d", p, len(headers), from)
|
|
select {
|
|
case d.headerProcCh <- headers:
|
|
case <-d.cancelCh:
|
|
return errCancelHeaderFetch
|
|
}
|
|
from += uint64(len(headers))
|
|
}
|
|
getHeaders(from)
|
|
|
|
case <-timeout.C:
|
|
// Header retrieval timed out, consider the peer bad and drop
|
|
glog.V(logger.Debug).Infof("%v: header request timed out", p)
|
|
headerTimeoutMeter.Mark(1)
|
|
d.dropPeer(p.id)
|
|
|
|
// Finish the sync gracefully instead of dumping the gathered data though
|
|
for _, ch := range []chan bool{d.bodyWakeCh, d.receiptWakeCh, d.stateWakeCh} {
|
|
select {
|
|
case ch <- false:
|
|
case <-d.cancelCh:
|
|
}
|
|
}
|
|
select {
|
|
case d.headerProcCh <- nil:
|
|
case <-d.cancelCh:
|
|
}
|
|
return errBadPeer
|
|
}
|
|
}
|
|
}
|
|
|
|
// fillHeaderSkeleton concurrently retrieves headers from all our available peers
|
|
// and maps them to the provided skeleton header chain.
|
|
//
|
|
// Any partial results from the beginning of the skeleton is (if possible) forwarded
|
|
// immediately to the header processor to keep the rest of the pipeline full even
|
|
// in the case of header stalls.
|
|
//
|
|
// The method returs the entire filled skeleton and also the number of headers
|
|
// already forwarded for processing.
|
|
func (d *Downloader) fillHeaderSkeleton(from uint64, skeleton []*types.Header) ([]*types.Header, int, error) {
|
|
glog.V(logger.Debug).Infof("Filling up skeleton from #%d", from)
|
|
d.queue.ScheduleSkeleton(from, skeleton)
|
|
|
|
var (
|
|
deliver = func(packet dataPack) (int, error) {
|
|
pack := packet.(*headerPack)
|
|
return d.queue.DeliverHeaders(pack.peerId, pack.headers, d.headerProcCh)
|
|
}
|
|
expire = func() map[string]int { return d.queue.ExpireHeaders(d.requestTTL()) }
|
|
throttle = func() bool { return false }
|
|
reserve = func(p *peer, count int) (*fetchRequest, bool, error) {
|
|
return d.queue.ReserveHeaders(p, count), false, nil
|
|
}
|
|
fetch = func(p *peer, req *fetchRequest) error { return p.FetchHeaders(req.From, MaxHeaderFetch) }
|
|
capacity = func(p *peer) int { return p.HeaderCapacity(d.requestRTT()) }
|
|
setIdle = func(p *peer, accepted int) { p.SetHeadersIdle(accepted) }
|
|
)
|
|
err := d.fetchParts(errCancelHeaderFetch, d.headerCh, deliver, d.queue.headerContCh, expire,
|
|
d.queue.PendingHeaders, d.queue.InFlightHeaders, throttle, reserve,
|
|
nil, fetch, d.queue.CancelHeaders, capacity, d.peers.HeaderIdlePeers, setIdle, "Header")
|
|
|
|
glog.V(logger.Debug).Infof("Skeleton fill terminated: %v", err)
|
|
|
|
filled, proced := d.queue.RetrieveHeaders()
|
|
return filled, proced, err
|
|
}
|
|
|
|
// fetchBodies iteratively downloads the scheduled block bodies, taking any
|
|
// available peers, reserving a chunk of blocks for each, waiting for delivery
|
|
// and also periodically checking for timeouts.
|
|
func (d *Downloader) fetchBodies(from uint64) error {
|
|
glog.V(logger.Debug).Infof("Downloading block bodies from #%d", from)
|
|
|
|
var (
|
|
deliver = func(packet dataPack) (int, error) {
|
|
pack := packet.(*bodyPack)
|
|
return d.queue.DeliverBodies(pack.peerId, pack.transactions, pack.uncles)
|
|
}
|
|
expire = func() map[string]int { return d.queue.ExpireBodies(d.requestTTL()) }
|
|
fetch = func(p *peer, req *fetchRequest) error { return p.FetchBodies(req) }
|
|
capacity = func(p *peer) int { return p.BlockCapacity(d.requestRTT()) }
|
|
setIdle = func(p *peer, accepted int) { p.SetBodiesIdle(accepted) }
|
|
)
|
|
err := d.fetchParts(errCancelBodyFetch, d.bodyCh, deliver, d.bodyWakeCh, expire,
|
|
d.queue.PendingBlocks, d.queue.InFlightBlocks, d.queue.ShouldThrottleBlocks, d.queue.ReserveBodies,
|
|
d.bodyFetchHook, fetch, d.queue.CancelBodies, capacity, d.peers.BodyIdlePeers, setIdle, "Body")
|
|
|
|
glog.V(logger.Debug).Infof("Block body download terminated: %v", err)
|
|
return err
|
|
}
|
|
|
|
// fetchReceipts iteratively downloads the scheduled block receipts, taking any
|
|
// available peers, reserving a chunk of receipts for each, waiting for delivery
|
|
// and also periodically checking for timeouts.
|
|
func (d *Downloader) fetchReceipts(from uint64) error {
|
|
glog.V(logger.Debug).Infof("Downloading receipts from #%d", from)
|
|
|
|
var (
|
|
deliver = func(packet dataPack) (int, error) {
|
|
pack := packet.(*receiptPack)
|
|
return d.queue.DeliverReceipts(pack.peerId, pack.receipts)
|
|
}
|
|
expire = func() map[string]int { return d.queue.ExpireReceipts(d.requestTTL()) }
|
|
fetch = func(p *peer, req *fetchRequest) error { return p.FetchReceipts(req) }
|
|
capacity = func(p *peer) int { return p.ReceiptCapacity(d.requestRTT()) }
|
|
setIdle = func(p *peer, accepted int) { p.SetReceiptsIdle(accepted) }
|
|
)
|
|
err := d.fetchParts(errCancelReceiptFetch, d.receiptCh, deliver, d.receiptWakeCh, expire,
|
|
d.queue.PendingReceipts, d.queue.InFlightReceipts, d.queue.ShouldThrottleReceipts, d.queue.ReserveReceipts,
|
|
d.receiptFetchHook, fetch, d.queue.CancelReceipts, capacity, d.peers.ReceiptIdlePeers, setIdle, "Receipt")
|
|
|
|
glog.V(logger.Debug).Infof("Receipt download terminated: %v", err)
|
|
return err
|
|
}
|
|
|
|
// fetchNodeData iteratively downloads the scheduled state trie nodes, taking any
|
|
// available peers, reserving a chunk of nodes for each, waiting for delivery and
|
|
// also periodically checking for timeouts.
|
|
func (d *Downloader) fetchNodeData() error {
|
|
glog.V(logger.Debug).Infof("Downloading node state data")
|
|
|
|
var (
|
|
deliver = func(packet dataPack) (int, error) {
|
|
start := time.Now()
|
|
return d.queue.DeliverNodeData(packet.PeerId(), packet.(*statePack).states, func(delivered int, progressed bool, err error) {
|
|
// If the peer returned old-requested data, forgive
|
|
if err == trie.ErrNotRequested {
|
|
glog.V(logger.Debug).Infof("peer %s: replied to stale state request, forgiving", packet.PeerId())
|
|
return
|
|
}
|
|
if err != nil {
|
|
// If the node data processing failed, the root hash is very wrong, abort
|
|
glog.V(logger.Error).Infof("peer %d: state processing failed: %v", packet.PeerId(), err)
|
|
d.cancel()
|
|
return
|
|
}
|
|
// Processing succeeded, notify state fetcher of continuation
|
|
pending := d.queue.PendingNodeData()
|
|
if pending > 0 {
|
|
select {
|
|
case d.stateWakeCh <- true:
|
|
default:
|
|
}
|
|
}
|
|
d.syncStatsLock.Lock()
|
|
d.syncStatsStateDone += uint64(delivered)
|
|
syncStatsStateDone := d.syncStatsStateDone // Thread safe copy for the log below
|
|
d.syncStatsLock.Unlock()
|
|
|
|
// If real database progress was made, reset any fast-sync pivot failure
|
|
if progressed && atomic.LoadUint32(&d.fsPivotFails) > 1 {
|
|
glog.V(logger.Debug).Infof("fast-sync progressed, resetting fail counter from %d", atomic.LoadUint32(&d.fsPivotFails))
|
|
atomic.StoreUint32(&d.fsPivotFails, 1) // Don't ever reset to 0, as that will unlock the pivot block
|
|
}
|
|
// Log a message to the user and return
|
|
if delivered > 0 {
|
|
glog.V(logger.Info).Infof("imported %3d state entries in %9v: processed %d, pending at least %d", delivered, common.PrettyDuration(time.Since(start)), syncStatsStateDone, pending)
|
|
}
|
|
})
|
|
}
|
|
expire = func() map[string]int { return d.queue.ExpireNodeData(d.requestTTL()) }
|
|
throttle = func() bool { return false }
|
|
reserve = func(p *peer, count int) (*fetchRequest, bool, error) {
|
|
return d.queue.ReserveNodeData(p, count), false, nil
|
|
}
|
|
fetch = func(p *peer, req *fetchRequest) error { return p.FetchNodeData(req) }
|
|
capacity = func(p *peer) int { return p.NodeDataCapacity(d.requestRTT()) }
|
|
setIdle = func(p *peer, accepted int) { p.SetNodeDataIdle(accepted) }
|
|
)
|
|
err := d.fetchParts(errCancelStateFetch, d.stateCh, deliver, d.stateWakeCh, expire,
|
|
d.queue.PendingNodeData, d.queue.InFlightNodeData, throttle, reserve, nil, fetch,
|
|
d.queue.CancelNodeData, capacity, d.peers.NodeDataIdlePeers, setIdle, "State")
|
|
|
|
glog.V(logger.Debug).Infof("Node state data download terminated: %v", err)
|
|
return err
|
|
}
|
|
|
|
// fetchParts iteratively downloads scheduled block parts, taking any available
|
|
// peers, reserving a chunk of fetch requests for each, waiting for delivery and
|
|
// also periodically checking for timeouts.
|
|
//
|
|
// As the scheduling/timeout logic mostly is the same for all downloaded data
|
|
// types, this method is used by each for data gathering and is instrumented with
|
|
// various callbacks to handle the slight differences between processing them.
|
|
//
|
|
// The instrumentation parameters:
|
|
// - errCancel: error type to return if the fetch operation is cancelled (mostly makes logging nicer)
|
|
// - deliveryCh: channel from which to retrieve downloaded data packets (merged from all concurrent peers)
|
|
// - deliver: processing callback to deliver data packets into type specific download queues (usually within `queue`)
|
|
// - wakeCh: notification channel for waking the fetcher when new tasks are available (or sync completed)
|
|
// - expire: task callback method to abort requests that took too long and return the faulty peers (traffic shaping)
|
|
// - pending: task callback for the number of requests still needing download (detect completion/non-completability)
|
|
// - inFlight: task callback for the number of in-progress requests (wait for all active downloads to finish)
|
|
// - throttle: task callback to check if the processing queue is full and activate throttling (bound memory use)
|
|
// - reserve: task callback to reserve new download tasks to a particular peer (also signals partial completions)
|
|
// - fetchHook: tester callback to notify of new tasks being initiated (allows testing the scheduling logic)
|
|
// - fetch: network callback to actually send a particular download request to a physical remote peer
|
|
// - cancel: task callback to abort an in-flight download request and allow rescheduling it (in case of lost peer)
|
|
// - capacity: network callback to retrieve the estimated type-specific bandwidth capacity of a peer (traffic shaping)
|
|
// - idle: network callback to retrieve the currently (type specific) idle peers that can be assigned tasks
|
|
// - setIdle: network callback to set a peer back to idle and update its estimated capacity (traffic shaping)
|
|
// - kind: textual label of the type being downloaded to display in log mesages
|
|
func (d *Downloader) fetchParts(errCancel error, deliveryCh chan dataPack, deliver func(dataPack) (int, error), wakeCh chan bool,
|
|
expire func() map[string]int, pending func() int, inFlight func() bool, throttle func() bool, reserve func(*peer, int) (*fetchRequest, bool, error),
|
|
fetchHook func([]*types.Header), fetch func(*peer, *fetchRequest) error, cancel func(*fetchRequest), capacity func(*peer) int,
|
|
idle func() ([]*peer, int), setIdle func(*peer, int), kind string) error {
|
|
|
|
// Create a ticker to detect expired retrieval tasks
|
|
ticker := time.NewTicker(100 * time.Millisecond)
|
|
defer ticker.Stop()
|
|
|
|
update := make(chan struct{}, 1)
|
|
|
|
// Prepare the queue and fetch block parts until the block header fetcher's done
|
|
finished := false
|
|
for {
|
|
select {
|
|
case <-d.cancelCh:
|
|
return errCancel
|
|
|
|
case packet := <-deliveryCh:
|
|
// If the peer was previously banned and failed to deliver it's pack
|
|
// in a reasonable time frame, ignore it's message.
|
|
if peer := d.peers.Peer(packet.PeerId()); peer != nil {
|
|
// Deliver the received chunk of data and check chain validity
|
|
accepted, err := deliver(packet)
|
|
if err == errInvalidChain {
|
|
return err
|
|
}
|
|
// Unless a peer delivered something completely else than requested (usually
|
|
// caused by a timed out request which came through in the end), set it to
|
|
// idle. If the delivery's stale, the peer should have already been idled.
|
|
if err != errStaleDelivery {
|
|
setIdle(peer, accepted)
|
|
}
|
|
// Issue a log to the user to see what's going on
|
|
switch {
|
|
case err == nil && packet.Items() == 0:
|
|
glog.V(logger.Detail).Infof("%s: no %s delivered", peer, strings.ToLower(kind))
|
|
case err == nil:
|
|
glog.V(logger.Detail).Infof("%s: delivered %s %s(s)", peer, packet.Stats(), strings.ToLower(kind))
|
|
default:
|
|
glog.V(logger.Detail).Infof("%s: %s delivery failed: %v", peer, strings.ToLower(kind), err)
|
|
}
|
|
}
|
|
// Blocks assembled, try to update the progress
|
|
select {
|
|
case update <- struct{}{}:
|
|
default:
|
|
}
|
|
|
|
case cont := <-wakeCh:
|
|
// The header fetcher sent a continuation flag, check if it's done
|
|
if !cont {
|
|
finished = true
|
|
}
|
|
// Headers arrive, try to update the progress
|
|
select {
|
|
case update <- struct{}{}:
|
|
default:
|
|
}
|
|
|
|
case <-ticker.C:
|
|
// Sanity check update the progress
|
|
select {
|
|
case update <- struct{}{}:
|
|
default:
|
|
}
|
|
|
|
case <-update:
|
|
// Short circuit if we lost all our peers
|
|
if d.peers.Len() == 0 {
|
|
return errNoPeers
|
|
}
|
|
// Check for fetch request timeouts and demote the responsible peers
|
|
for pid, fails := range expire() {
|
|
if peer := d.peers.Peer(pid); peer != nil {
|
|
// If a lot of retrieval elements expired, we might have overestimated the remote peer or perhaps
|
|
// ourselves. Only reset to minimal throughput but don't drop just yet. If even the minimal times
|
|
// out that sync wise we need to get rid of the peer.
|
|
//
|
|
// The reason the minimum threshold is 2 is because the downloader tries to estimate the bandwidth
|
|
// and latency of a peer separately, which requires pushing the measures capacity a bit and seeing
|
|
// how response times reacts, to it always requests one more than the minimum (i.e. min 2).
|
|
if fails > 2 {
|
|
glog.V(logger.Detail).Infof("%s: %s delivery timeout", peer, strings.ToLower(kind))
|
|
setIdle(peer, 0)
|
|
} else {
|
|
glog.V(logger.Debug).Infof("%s: stalling %s delivery, dropping", peer, strings.ToLower(kind))
|
|
d.dropPeer(pid)
|
|
}
|
|
}
|
|
}
|
|
// If there's nothing more to fetch, wait or terminate
|
|
if pending() == 0 {
|
|
if !inFlight() && finished {
|
|
glog.V(logger.Debug).Infof("%s fetching completed", kind)
|
|
return nil
|
|
}
|
|
break
|
|
}
|
|
// Send a download request to all idle peers, until throttled
|
|
progressed, throttled, running := false, false, inFlight()
|
|
idles, total := idle()
|
|
|
|
for _, peer := range idles {
|
|
// Short circuit if throttling activated
|
|
if throttle() {
|
|
throttled = true
|
|
break
|
|
}
|
|
// Reserve a chunk of fetches for a peer. A nil can mean either that
|
|
// no more headers are available, or that the peer is known not to
|
|
// have them.
|
|
request, progress, err := reserve(peer, capacity(peer))
|
|
if err != nil {
|
|
return err
|
|
}
|
|
if progress {
|
|
progressed = true
|
|
}
|
|
if request == nil {
|
|
continue
|
|
}
|
|
if glog.V(logger.Detail) {
|
|
if request.From > 0 {
|
|
glog.Infof("%s: requesting %s(s) from #%d", peer, strings.ToLower(kind), request.From)
|
|
} else if len(request.Headers) > 0 {
|
|
glog.Infof("%s: requesting %d %s(s), first at #%d", peer, len(request.Headers), strings.ToLower(kind), request.Headers[0].Number)
|
|
} else {
|
|
glog.Infof("%s: requesting %d %s(s)", peer, len(request.Hashes), strings.ToLower(kind))
|
|
}
|
|
}
|
|
// Fetch the chunk and make sure any errors return the hashes to the queue
|
|
if fetchHook != nil {
|
|
fetchHook(request.Headers)
|
|
}
|
|
if err := fetch(peer, request); err != nil {
|
|
// Although we could try and make an attempt to fix this, this error really
|
|
// means that we've double allocated a fetch task to a peer. If that is the
|
|
// case, the internal state of the downloader and the queue is very wrong so
|
|
// better hard crash and note the error instead of silently accumulating into
|
|
// a much bigger issue.
|
|
panic(fmt.Sprintf("%v: %s fetch assignment failed", peer, strings.ToLower(kind)))
|
|
}
|
|
running = true
|
|
}
|
|
// Make sure that we have peers available for fetching. If all peers have been tried
|
|
// and all failed throw an error
|
|
if !progressed && !throttled && !running && len(idles) == total && pending() > 0 {
|
|
return errPeersUnavailable
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// processHeaders takes batches of retrieved headers from an input channel and
|
|
// keeps processing and scheduling them into the header chain and downloader's
|
|
// queue until the stream ends or a failure occurs.
|
|
func (d *Downloader) processHeaders(origin uint64, td *big.Int) error {
|
|
// Calculate the pivoting point for switching from fast to slow sync
|
|
pivot := d.queue.FastSyncPivot()
|
|
|
|
// Keep a count of uncertain headers to roll back
|
|
rollback := []*types.Header{}
|
|
defer func() {
|
|
if len(rollback) > 0 {
|
|
// Flatten the headers and roll them back
|
|
hashes := make([]common.Hash, len(rollback))
|
|
for i, header := range rollback {
|
|
hashes[i] = header.Hash()
|
|
}
|
|
lastHeader, lastFastBlock, lastBlock := d.headHeader().Number, common.Big0, common.Big0
|
|
if d.headFastBlock != nil {
|
|
lastFastBlock = d.headFastBlock().Number()
|
|
}
|
|
if d.headBlock != nil {
|
|
lastBlock = d.headBlock().Number()
|
|
}
|
|
d.rollback(hashes)
|
|
curFastBlock, curBlock := common.Big0, common.Big0
|
|
if d.headFastBlock != nil {
|
|
curFastBlock = d.headFastBlock().Number()
|
|
}
|
|
if d.headBlock != nil {
|
|
curBlock = d.headBlock().Number()
|
|
}
|
|
glog.V(logger.Warn).Infof("Rolled back %d headers (LH: %d->%d, FB: %d->%d, LB: %d->%d)",
|
|
len(hashes), lastHeader, d.headHeader().Number, lastFastBlock, curFastBlock, lastBlock, curBlock)
|
|
|
|
// If we're already past the pivot point, this could be an attack, thread carefully
|
|
if rollback[len(rollback)-1].Number.Uint64() > pivot {
|
|
// If we didn't ever fail, lock in te pivot header (must! not! change!)
|
|
if atomic.LoadUint32(&d.fsPivotFails) == 0 {
|
|
for _, header := range rollback {
|
|
if header.Number.Uint64() == pivot {
|
|
glog.V(logger.Warn).Infof("Fast-sync critical section failure, locked pivot to header #%d [%x…]", pivot, header.Hash().Bytes()[:4])
|
|
d.fsPivotLock = header
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}()
|
|
|
|
// Wait for batches of headers to process
|
|
gotHeaders := false
|
|
|
|
for {
|
|
select {
|
|
case <-d.cancelCh:
|
|
return errCancelHeaderProcessing
|
|
|
|
case headers := <-d.headerProcCh:
|
|
// Terminate header processing if we synced up
|
|
if len(headers) == 0 {
|
|
// Notify everyone that headers are fully processed
|
|
for _, ch := range []chan bool{d.bodyWakeCh, d.receiptWakeCh, d.stateWakeCh} {
|
|
select {
|
|
case ch <- false:
|
|
case <-d.cancelCh:
|
|
}
|
|
}
|
|
// If no headers were retrieved at all, the peer violated it's TD promise that it had a
|
|
// better chain compared to ours. The only exception is if it's promised blocks were
|
|
// already imported by other means (e.g. fecher):
|
|
//
|
|
// R <remote peer>, L <local node>: Both at block 10
|
|
// R: Mine block 11, and propagate it to L
|
|
// L: Queue block 11 for import
|
|
// L: Notice that R's head and TD increased compared to ours, start sync
|
|
// L: Import of block 11 finishes
|
|
// L: Sync begins, and finds common ancestor at 11
|
|
// L: Request new headers up from 11 (R's TD was higher, it must have something)
|
|
// R: Nothing to give
|
|
if d.mode != LightSync {
|
|
if !gotHeaders && td.Cmp(d.getTd(d.headBlock().Hash())) > 0 {
|
|
return errStallingPeer
|
|
}
|
|
}
|
|
// If fast or light syncing, ensure promised headers are indeed delivered. This is
|
|
// needed to detect scenarios where an attacker feeds a bad pivot and then bails out
|
|
// of delivering the post-pivot blocks that would flag the invalid content.
|
|
//
|
|
// This check cannot be executed "as is" for full imports, since blocks may still be
|
|
// queued for processing when the header download completes. However, as long as the
|
|
// peer gave us something useful, we're already happy/progressed (above check).
|
|
if d.mode == FastSync || d.mode == LightSync {
|
|
if td.Cmp(d.getTd(d.headHeader().Hash())) > 0 {
|
|
return errStallingPeer
|
|
}
|
|
}
|
|
// Disable any rollback and return
|
|
rollback = nil
|
|
return nil
|
|
}
|
|
// Otherwise split the chunk of headers into batches and process them
|
|
gotHeaders = true
|
|
|
|
for len(headers) > 0 {
|
|
// Terminate if something failed in between processing chunks
|
|
select {
|
|
case <-d.cancelCh:
|
|
return errCancelHeaderProcessing
|
|
default:
|
|
}
|
|
// Select the next chunk of headers to import
|
|
limit := maxHeadersProcess
|
|
if limit > len(headers) {
|
|
limit = len(headers)
|
|
}
|
|
chunk := headers[:limit]
|
|
|
|
// In case of header only syncing, validate the chunk immediately
|
|
if d.mode == FastSync || d.mode == LightSync {
|
|
// Collect the yet unknown headers to mark them as uncertain
|
|
unknown := make([]*types.Header, 0, len(headers))
|
|
for _, header := range chunk {
|
|
if !d.hasHeader(header.Hash()) {
|
|
unknown = append(unknown, header)
|
|
}
|
|
}
|
|
// If we're importing pure headers, verify based on their recentness
|
|
frequency := fsHeaderCheckFrequency
|
|
if chunk[len(chunk)-1].Number.Uint64()+uint64(fsHeaderForceVerify) > pivot {
|
|
frequency = 1
|
|
}
|
|
if n, err := d.insertHeaders(chunk, frequency); err != nil {
|
|
// If some headers were inserted, add them too to the rollback list
|
|
if n > 0 {
|
|
rollback = append(rollback, chunk[:n]...)
|
|
}
|
|
glog.V(logger.Debug).Infof("invalid header #%d [%x…]: %v", chunk[n].Number, chunk[n].Hash().Bytes()[:4], err)
|
|
return errInvalidChain
|
|
}
|
|
// All verifications passed, store newly found uncertain headers
|
|
rollback = append(rollback, unknown...)
|
|
if len(rollback) > fsHeaderSafetyNet {
|
|
rollback = append(rollback[:0], rollback[len(rollback)-fsHeaderSafetyNet:]...)
|
|
}
|
|
}
|
|
// If we're fast syncing and just pulled in the pivot, make sure it's the one locked in
|
|
if d.mode == FastSync && d.fsPivotLock != nil && chunk[0].Number.Uint64() <= pivot && chunk[len(chunk)-1].Number.Uint64() >= pivot {
|
|
if pivot := chunk[int(pivot-chunk[0].Number.Uint64())]; pivot.Hash() != d.fsPivotLock.Hash() {
|
|
glog.V(logger.Warn).Infof("Pivot doesn't match locked in version: have #%v [%x…], want #%v [%x…]", pivot.Number, pivot.Hash().Bytes()[:4], d.fsPivotLock.Number, d.fsPivotLock.Hash().Bytes()[:4])
|
|
return errInvalidChain
|
|
}
|
|
}
|
|
// Unless we're doing light chains, schedule the headers for associated content retrieval
|
|
if d.mode == FullSync || d.mode == FastSync {
|
|
// If we've reached the allowed number of pending headers, stall a bit
|
|
for d.queue.PendingBlocks() >= maxQueuedHeaders || d.queue.PendingReceipts() >= maxQueuedHeaders {
|
|
select {
|
|
case <-d.cancelCh:
|
|
return errCancelHeaderProcessing
|
|
case <-time.After(time.Second):
|
|
}
|
|
}
|
|
// Otherwise insert the headers for content retrieval
|
|
inserts := d.queue.Schedule(chunk, origin)
|
|
if len(inserts) != len(chunk) {
|
|
glog.V(logger.Debug).Infof("stale headers")
|
|
return errBadPeer
|
|
}
|
|
}
|
|
headers = headers[limit:]
|
|
origin += uint64(limit)
|
|
}
|
|
// Signal the content downloaders of the availablility of new tasks
|
|
for _, ch := range []chan bool{d.bodyWakeCh, d.receiptWakeCh, d.stateWakeCh} {
|
|
select {
|
|
case ch <- true:
|
|
default:
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// processContent takes fetch results from the queue and tries to import them
|
|
// into the chain. The type of import operation will depend on the result contents.
|
|
func (d *Downloader) processContent() error {
|
|
pivot := d.queue.FastSyncPivot()
|
|
for {
|
|
results := d.queue.WaitResults()
|
|
if len(results) == 0 {
|
|
return nil // queue empty
|
|
}
|
|
if d.chainInsertHook != nil {
|
|
d.chainInsertHook(results)
|
|
}
|
|
// Actually import the blocks
|
|
if glog.V(logger.Debug) {
|
|
first, last := results[0].Header, results[len(results)-1].Header
|
|
glog.Infof("Inserting chain with %d items (#%d [%x…] - #%d [%x…])", len(results), first.Number, first.Hash().Bytes()[:4], last.Number, last.Hash().Bytes()[:4])
|
|
}
|
|
for len(results) != 0 {
|
|
// Check for any termination requests
|
|
select {
|
|
case <-d.quitCh:
|
|
return errCancelContentProcessing
|
|
default:
|
|
}
|
|
// Retrieve the a batch of results to import
|
|
var (
|
|
blocks = make([]*types.Block, 0, maxResultsProcess)
|
|
receipts = make([]types.Receipts, 0, maxResultsProcess)
|
|
)
|
|
items := int(math.Min(float64(len(results)), float64(maxResultsProcess)))
|
|
for _, result := range results[:items] {
|
|
switch {
|
|
case d.mode == FullSync:
|
|
blocks = append(blocks, types.NewBlockWithHeader(result.Header).WithBody(result.Transactions, result.Uncles))
|
|
case d.mode == FastSync:
|
|
blocks = append(blocks, types.NewBlockWithHeader(result.Header).WithBody(result.Transactions, result.Uncles))
|
|
if result.Header.Number.Uint64() <= pivot {
|
|
receipts = append(receipts, result.Receipts)
|
|
}
|
|
}
|
|
}
|
|
// Try to process the results, aborting if there's an error
|
|
var (
|
|
err error
|
|
index int
|
|
)
|
|
switch {
|
|
case len(receipts) > 0:
|
|
index, err = d.insertReceipts(blocks, receipts)
|
|
if err == nil && blocks[len(blocks)-1].NumberU64() == pivot {
|
|
glog.V(logger.Debug).Infof("Committing block #%d [%x…] as the new head", blocks[len(blocks)-1].Number(), blocks[len(blocks)-1].Hash().Bytes()[:4])
|
|
index, err = len(blocks)-1, d.commitHeadBlock(blocks[len(blocks)-1].Hash())
|
|
}
|
|
default:
|
|
index, err = d.insertBlocks(blocks)
|
|
}
|
|
if err != nil {
|
|
glog.V(logger.Debug).Infof("Result #%d [%x…] processing failed: %v", results[index].Header.Number, results[index].Header.Hash().Bytes()[:4], err)
|
|
return errInvalidChain
|
|
}
|
|
// Shift the results to the next batch
|
|
results = results[items:]
|
|
}
|
|
}
|
|
}
|
|
|
|
// DeliverHeaders injects a new batch of block headers received from a remote
|
|
// node into the download schedule.
|
|
func (d *Downloader) DeliverHeaders(id string, headers []*types.Header) (err error) {
|
|
return d.deliver(id, d.headerCh, &headerPack{id, headers}, headerInMeter, headerDropMeter)
|
|
}
|
|
|
|
// DeliverBodies injects a new batch of block bodies received from a remote node.
|
|
func (d *Downloader) DeliverBodies(id string, transactions [][]*types.Transaction, uncles [][]*types.Header) (err error) {
|
|
return d.deliver(id, d.bodyCh, &bodyPack{id, transactions, uncles}, bodyInMeter, bodyDropMeter)
|
|
}
|
|
|
|
// DeliverReceipts injects a new batch of receipts received from a remote node.
|
|
func (d *Downloader) DeliverReceipts(id string, receipts [][]*types.Receipt) (err error) {
|
|
return d.deliver(id, d.receiptCh, &receiptPack{id, receipts}, receiptInMeter, receiptDropMeter)
|
|
}
|
|
|
|
// DeliverNodeData injects a new batch of node state data received from a remote node.
|
|
func (d *Downloader) DeliverNodeData(id string, data [][]byte) (err error) {
|
|
return d.deliver(id, d.stateCh, &statePack{id, data}, stateInMeter, stateDropMeter)
|
|
}
|
|
|
|
// deliver injects a new batch of data received from a remote node.
|
|
func (d *Downloader) deliver(id string, destCh chan dataPack, packet dataPack, inMeter, dropMeter metrics.Meter) (err error) {
|
|
// Update the delivery metrics for both good and failed deliveries
|
|
inMeter.Mark(int64(packet.Items()))
|
|
defer func() {
|
|
if err != nil {
|
|
dropMeter.Mark(int64(packet.Items()))
|
|
}
|
|
}()
|
|
// Deliver or abort if the sync is canceled while queuing
|
|
d.cancelLock.RLock()
|
|
cancel := d.cancelCh
|
|
d.cancelLock.RUnlock()
|
|
if cancel == nil {
|
|
return errNoSyncActive
|
|
}
|
|
select {
|
|
case destCh <- packet:
|
|
return nil
|
|
case <-cancel:
|
|
return errNoSyncActive
|
|
}
|
|
}
|
|
|
|
// qosTuner is the quality of service tuning loop that occasionally gathers the
|
|
// peer latency statistics and updates the estimated request round trip time.
|
|
func (d *Downloader) qosTuner() {
|
|
for {
|
|
// Retrieve the current median RTT and integrate into the previoust target RTT
|
|
rtt := time.Duration(float64(1-qosTuningImpact)*float64(atomic.LoadUint64(&d.rttEstimate)) + qosTuningImpact*float64(d.peers.medianRTT()))
|
|
atomic.StoreUint64(&d.rttEstimate, uint64(rtt))
|
|
|
|
// A new RTT cycle passed, increase our confidence in the estimated RTT
|
|
conf := atomic.LoadUint64(&d.rttConfidence)
|
|
conf = conf + (1000000-conf)/2
|
|
atomic.StoreUint64(&d.rttConfidence, conf)
|
|
|
|
// Log the new QoS values and sleep until the next RTT
|
|
glog.V(logger.Debug).Infof("Quality of service: rtt %v, conf %.3f, ttl %v", rtt, float64(conf)/1000000.0, d.requestTTL())
|
|
select {
|
|
case <-d.quitCh:
|
|
return
|
|
case <-time.After(rtt):
|
|
}
|
|
}
|
|
}
|
|
|
|
// qosReduceConfidence is meant to be called when a new peer joins the downloader's
|
|
// peer set, needing to reduce the confidence we have in out QoS estimates.
|
|
func (d *Downloader) qosReduceConfidence() {
|
|
// If we have a single peer, confidence is always 1
|
|
peers := uint64(d.peers.Len())
|
|
if peers == 1 {
|
|
atomic.StoreUint64(&d.rttConfidence, 1000000)
|
|
return
|
|
}
|
|
// If we have a ton of peers, don't drop confidence)
|
|
if peers >= uint64(qosConfidenceCap) {
|
|
return
|
|
}
|
|
// Otherwise drop the confidence factor
|
|
conf := atomic.LoadUint64(&d.rttConfidence) * (peers - 1) / peers
|
|
if float64(conf)/1000000 < rttMinConfidence {
|
|
conf = uint64(rttMinConfidence * 1000000)
|
|
}
|
|
atomic.StoreUint64(&d.rttConfidence, conf)
|
|
|
|
rtt := time.Duration(atomic.LoadUint64(&d.rttEstimate))
|
|
glog.V(logger.Debug).Infof("Quality of service: rtt %v, conf %.3f, ttl %v", rtt, float64(conf)/1000000.0, d.requestTTL())
|
|
}
|
|
|
|
// requestRTT returns the current target round trip time for a download request
|
|
// to complete in.
|
|
//
|
|
// Note, the returned RTT is .9 of the actually estimated RTT. The reason is that
|
|
// the downloader tries to adapt queries to the RTT, so multiple RTT values can
|
|
// be adapted to, but smaller ones are preffered (stabler download stream).
|
|
func (d *Downloader) requestRTT() time.Duration {
|
|
return time.Duration(atomic.LoadUint64(&d.rttEstimate)) * 9 / 10
|
|
}
|
|
|
|
// requestTTL returns the current timeout allowance for a single download request
|
|
// to finish under.
|
|
func (d *Downloader) requestTTL() time.Duration {
|
|
var (
|
|
rtt = time.Duration(atomic.LoadUint64(&d.rttEstimate))
|
|
conf = float64(atomic.LoadUint64(&d.rttConfidence)) / 1000000.0
|
|
)
|
|
ttl := time.Duration(ttlScaling) * time.Duration(float64(rtt)/conf)
|
|
if ttl > ttlLimit {
|
|
ttl = ttlLimit
|
|
}
|
|
return ttl
|
|
}
|