841 lines
28 KiB
Go
841 lines
28 KiB
Go
// Copyright 2015 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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// Package downloader contains the manual full chain synchronisation.
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package downloader
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import (
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"errors"
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"math"
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"math/big"
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"sync"
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"sync/atomic"
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"time"
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"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/core"
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"github.com/ethereum/go-ethereum/core/types"
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"github.com/ethereum/go-ethereum/event"
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"github.com/ethereum/go-ethereum/logger"
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"github.com/ethereum/go-ethereum/logger/glog"
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"gopkg.in/fatih/set.v0"
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)
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const (
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eth61 = 61 // Constant to check for old protocol support
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eth62 = 62 // Constant to check for new protocol support
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)
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var (
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MinHashFetch = 512 // Minimum amount of hashes to not consider a peer stalling
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MaxHashFetch = 512 // Amount of hashes to be fetched per retrieval request
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MaxBlockFetch = 128 // Amount of blocks to be fetched per retrieval request
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MaxHeaderFetch = 256 // Amount of block headers to be fetched per retrieval request
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MaxStateFetch = 384 // Amount of node state values to allow fetching per request
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MaxReceiptsFetch = 384 // Amount of transaction receipts to allow fetching per request
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hashTTL = 5 * time.Second // Time it takes for a hash request to time out
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blockSoftTTL = 3 * time.Second // Request completion threshold for increasing or decreasing a peer's bandwidth
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blockHardTTL = 3 * blockSoftTTL // Maximum time allowance before a block request is considered expired
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crossCheckCycle = time.Second // Period after which to check for expired cross checks
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maxQueuedHashes = 256 * 1024 // Maximum number of hashes to queue for import (DOS protection)
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maxBannedHashes = 4096 // Number of bannable hashes before phasing old ones out
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maxBlockProcess = 256 // Number of blocks to import at once into the chain
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)
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var (
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errBusy = errors.New("busy")
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errUnknownPeer = errors.New("peer is unknown or unhealthy")
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errBadPeer = errors.New("action from bad peer ignored")
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errStallingPeer = errors.New("peer is stalling")
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errBannedHead = errors.New("peer head hash already banned")
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errNoPeers = errors.New("no peers to keep download active")
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errPendingQueue = errors.New("pending items in queue")
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errTimeout = errors.New("timeout")
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errEmptyHashSet = errors.New("empty hash set by peer")
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errPeersUnavailable = errors.New("no peers available or all peers tried for block download process")
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errAlreadyInPool = errors.New("hash already in pool")
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errInvalidChain = errors.New("retrieved hash chain is invalid")
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errCrossCheckFailed = errors.New("block cross-check failed")
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errCancelHashFetch = errors.New("hash fetching canceled (requested)")
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errCancelBlockFetch = errors.New("block downloading canceled (requested)")
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errNoSyncActive = errors.New("no sync active")
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)
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// hashCheckFn is a callback type for verifying a hash's presence in the local chain.
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type hashCheckFn func(common.Hash) bool
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// blockRetrievalFn is a callback type for retrieving a block from the local chain.
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type blockRetrievalFn func(common.Hash) *types.Block
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// headRetrievalFn is a callback type for retrieving the head block from the local chain.
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type headRetrievalFn func() *types.Block
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// chainInsertFn is a callback type to insert a batch of blocks into the local chain.
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type chainInsertFn func(types.Blocks) (int, error)
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// peerDropFn is a callback type for dropping a peer detected as malicious.
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type peerDropFn func(id string)
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type blockPack struct {
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peerId string
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blocks []*types.Block
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}
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type hashPack struct {
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peerId string
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hashes []common.Hash
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}
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type crossCheck struct {
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expire time.Time
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parent common.Hash
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}
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type Downloader struct {
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mux *event.TypeMux
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queue *queue // Scheduler for selecting the hashes to download
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peers *peerSet // Set of active peers from which download can proceed
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checks map[common.Hash]*crossCheck // Pending cross checks to verify a hash chain
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banned *set.Set // Set of hashes we've received and banned
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interrupt int32 // Atomic boolean to signal termination
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// Statistics
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importStart time.Time // Instance when the last blocks were taken from the cache
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importQueue []*Block // Previously taken blocks to check import progress
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importDone int // Number of taken blocks already imported from the last batch
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importLock sync.Mutex
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// Callbacks
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hasBlock hashCheckFn // Checks if a block is present in the chain
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getBlock blockRetrievalFn // Retrieves a block from the chain
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headBlock headRetrievalFn // Retrieves the head block from the chain
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insertChain chainInsertFn // Injects a batch of blocks into the chain
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dropPeer peerDropFn // Drops a peer for misbehaving
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// Status
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synchroniseMock func(id string, hash common.Hash) error // Replacement for synchronise during testing
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synchronising int32
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processing int32
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notified int32
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// Channels
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newPeerCh chan *peer
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hashCh chan hashPack // Channel receiving inbound hashes
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blockCh chan blockPack // Channel receiving inbound blocks
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processCh chan bool // Channel to signal the block fetcher of new or finished work
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cancelCh chan struct{} // Channel to cancel mid-flight syncs
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cancelLock sync.RWMutex // Lock to protect the cancel channel in delivers
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}
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// Block is an origin-tagged blockchain block.
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type Block struct {
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RawBlock *types.Block
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OriginPeer string
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}
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// New creates a new downloader to fetch hashes and blocks from remote peers.
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func New(mux *event.TypeMux, hasBlock hashCheckFn, getBlock blockRetrievalFn, headBlock headRetrievalFn, insertChain chainInsertFn, dropPeer peerDropFn) *Downloader {
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// Create the base downloader
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downloader := &Downloader{
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mux: mux,
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queue: newQueue(),
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peers: newPeerSet(),
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hasBlock: hasBlock,
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getBlock: getBlock,
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headBlock: headBlock,
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insertChain: insertChain,
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dropPeer: dropPeer,
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newPeerCh: make(chan *peer, 1),
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hashCh: make(chan hashPack, 1),
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blockCh: make(chan blockPack, 1),
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processCh: make(chan bool, 1),
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}
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// Inject all the known bad hashes
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downloader.banned = set.New()
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for hash, _ := range core.BadHashes {
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downloader.banned.Add(hash)
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}
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return downloader
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}
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// Stats retrieves the current status of the downloader.
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func (d *Downloader) Stats() (pending int, cached int, importing int, estimate time.Duration) {
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// Fetch the download status
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pending, cached = d.queue.Size()
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// Figure out the import progress
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d.importLock.Lock()
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defer d.importLock.Unlock()
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for len(d.importQueue) > 0 && d.hasBlock(d.importQueue[0].RawBlock.Hash()) {
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d.importQueue = d.importQueue[1:]
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d.importDone++
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}
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importing = len(d.importQueue)
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// Make an estimate on the total sync
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estimate = 0
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if d.importDone > 0 {
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estimate = time.Since(d.importStart) / time.Duration(d.importDone) * time.Duration(pending+cached+importing)
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}
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return
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}
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// Synchronising returns whether the downloader is currently retrieving blocks.
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func (d *Downloader) Synchronising() bool {
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return atomic.LoadInt32(&d.synchronising) > 0
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}
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// RegisterPeer injects a new download peer into the set of block source to be
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// used for fetching hashes and blocks from.
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func (d *Downloader) RegisterPeer(id string, version int, head common.Hash, getRelHashes relativeHashFetcherFn, getAbsHashes absoluteHashFetcherFn, getBlocks blockFetcherFn) error {
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// If the peer wants to send a banned hash, reject
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if d.banned.Has(head) {
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glog.V(logger.Debug).Infoln("Register rejected, head hash banned:", id)
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return errBannedHead
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}
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// Otherwise try to construct and register the peer
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glog.V(logger.Detail).Infoln("Registering peer", id)
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if err := d.peers.Register(newPeer(id, version, head, getRelHashes, getAbsHashes, getBlocks)); err != nil {
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glog.V(logger.Error).Infoln("Register failed:", err)
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return err
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}
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return nil
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}
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// UnregisterPeer remove a peer from the known list, preventing any action from
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// the specified peer.
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func (d *Downloader) UnregisterPeer(id string) error {
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glog.V(logger.Detail).Infoln("Unregistering peer", id)
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if err := d.peers.Unregister(id); err != nil {
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glog.V(logger.Error).Infoln("Unregister failed:", err)
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return err
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}
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return nil
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}
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// Synchronise tries to sync up our local block chain with a remote peer, both
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// adding various sanity checks as well as wrapping it with various log entries.
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func (d *Downloader) Synchronise(id string, head common.Hash, td *big.Int) {
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glog.V(logger.Detail).Infof("Attempting synchronisation: %v, head 0x%x, TD %v", id, head[:4], td)
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switch err := d.synchronise(id, head, td); err {
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case nil:
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glog.V(logger.Detail).Infof("Synchronisation completed")
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case errBusy:
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glog.V(logger.Detail).Infof("Synchronisation already in progress")
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case errTimeout, errBadPeer, errStallingPeer, errBannedHead, errEmptyHashSet, errPeersUnavailable, errInvalidChain, errCrossCheckFailed:
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glog.V(logger.Debug).Infof("Removing peer %v: %v", id, err)
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d.dropPeer(id)
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case errPendingQueue:
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glog.V(logger.Debug).Infoln("Synchronisation aborted:", err)
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default:
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glog.V(logger.Warn).Infof("Synchronisation failed: %v", err)
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}
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}
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// synchronise will select the peer and use it for synchronising. If an empty string is given
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// it will use the best peer possible and synchronize if it's TD is higher than our own. If any of the
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// checks fail an error will be returned. This method is synchronous
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func (d *Downloader) synchronise(id string, hash common.Hash, td *big.Int) error {
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// Mock out the synchonisation if testing
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if d.synchroniseMock != nil {
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return d.synchroniseMock(id, hash)
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}
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// Make sure only one goroutine is ever allowed past this point at once
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if !atomic.CompareAndSwapInt32(&d.synchronising, 0, 1) {
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return errBusy
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}
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defer atomic.StoreInt32(&d.synchronising, 0)
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// If the head hash is banned, terminate immediately
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if d.banned.Has(hash) {
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return errBannedHead
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}
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// Post a user notification of the sync (only once per session)
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if atomic.CompareAndSwapInt32(&d.notified, 0, 1) {
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glog.V(logger.Info).Infoln("Block synchronisation started")
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}
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// Abort if the queue still contains some leftover data
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if _, cached := d.queue.Size(); cached > 0 && d.queue.GetHeadBlock() != nil {
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return errPendingQueue
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}
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// Reset the queue and peer set to clean any internal leftover state
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d.queue.Reset()
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d.peers.Reset()
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d.checks = make(map[common.Hash]*crossCheck)
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// Create cancel channel for aborting mid-flight
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d.cancelLock.Lock()
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d.cancelCh = make(chan struct{})
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d.cancelLock.Unlock()
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// Retrieve the origin peer and initiate the downloading process
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p := d.peers.Peer(id)
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if p == nil {
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return errUnknownPeer
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}
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return d.syncWithPeer(p, hash, td)
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}
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// Has checks if the downloader knows about a particular hash, meaning that its
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// either already downloaded of pending retrieval.
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func (d *Downloader) Has(hash common.Hash) bool {
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return d.queue.Has(hash)
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}
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// syncWithPeer starts a block synchronization based on the hash chain from the
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// specified peer and head hash.
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func (d *Downloader) syncWithPeer(p *peer, hash common.Hash, td *big.Int) (err error) {
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d.mux.Post(StartEvent{})
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defer func() {
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// reset on error
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if err != nil {
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d.cancel()
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d.mux.Post(FailedEvent{err})
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} else {
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d.mux.Post(DoneEvent{})
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}
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}()
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glog.V(logger.Debug).Infof("Synchronizing with the network using: %s, eth/%d", p.id, p.version)
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switch p.version {
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case eth61:
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// Old eth/61, use forward, concurrent hash and block retrieval algorithm
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number, err := d.findAncestor(p)
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if err != nil {
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return err
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}
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errc := make(chan error, 2)
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go func() { errc <- d.fetchHashes(p, td, number+1) }()
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go func() { errc <- d.fetchBlocks(number + 1) }()
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// If any fetcher fails, cancel the other
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if err := <-errc; err != nil {
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d.cancel()
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<-errc
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return err
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}
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return <-errc
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default:
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// Something very wrong, stop right here
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glog.V(logger.Error).Infof("Unsupported eth protocol: %d", p.version)
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return errBadPeer
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}
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return nil
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}
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// cancel cancels all of the operations and resets the queue. It returns true
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// if the cancel operation was completed.
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func (d *Downloader) cancel() {
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// Close the current cancel channel
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d.cancelLock.Lock()
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if d.cancelCh != nil {
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select {
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case <-d.cancelCh:
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// Channel was already closed
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default:
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close(d.cancelCh)
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}
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}
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d.cancelLock.Unlock()
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// Reset the queue
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d.queue.Reset()
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}
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// Terminate interrupts the downloader, canceling all pending operations.
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func (d *Downloader) Terminate() {
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atomic.StoreInt32(&d.interrupt, 1)
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d.cancel()
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}
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// findAncestor tries to locate the common ancestor block of the local chain and
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// a remote peers blockchain. In the general case when our node was in sync and
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// on the correct chain, checking the top N blocks should already get us a match.
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// In the rare scenario when we ended up on a long soft fork (i.e. none of the
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// head blocks match), we do a binary search to find the common ancestor.
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func (d *Downloader) findAncestor(p *peer) (uint64, error) {
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glog.V(logger.Debug).Infof("%v: looking for common ancestor", p)
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// Request out head blocks to short circuit ancestor location
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head := d.headBlock().NumberU64()
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from := int64(head) - int64(MaxHashFetch)
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if from < 0 {
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from = 0
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}
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go p.getAbsHashes(uint64(from), MaxHashFetch)
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// Wait for the remote response to the head fetch
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number, hash := uint64(0), common.Hash{}
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timeout := time.After(hashTTL)
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for finished := false; !finished; {
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select {
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case <-d.cancelCh:
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return 0, errCancelHashFetch
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case hashPack := <-d.hashCh:
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// Discard anything not from the origin peer
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if hashPack.peerId != p.id {
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glog.V(logger.Debug).Infof("Received hashes from incorrect peer(%s)", hashPack.peerId)
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break
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}
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// Make sure the peer actually gave something valid
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hashes := hashPack.hashes
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if len(hashes) == 0 {
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glog.V(logger.Debug).Infof("%v: empty head hash set", p)
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return 0, errEmptyHashSet
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}
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// Check if a common ancestor was found
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finished = true
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for i := len(hashes) - 1; i >= 0; i-- {
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if d.hasBlock(hashes[i]) {
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number, hash = uint64(from)+uint64(i), hashes[i]
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break
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}
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}
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case <-d.blockCh:
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// Out of bounds blocks received, ignore them
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case <-timeout:
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glog.V(logger.Debug).Infof("%v: head hash timeout", p)
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return 0, errTimeout
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}
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}
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// If the head fetch already found an ancestor, return
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if !common.EmptyHash(hash) {
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glog.V(logger.Debug).Infof("%v: common ancestor: #%d [%x]", p, number, hash[:4])
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return number, nil
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}
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// Ancestor not found, we need to binary search over our chain
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start, end := uint64(0), head
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for start+1 < end {
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// Split our chain interval in two, and request the hash to cross check
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check := (start + end) / 2
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timeout := time.After(hashTTL)
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go p.getAbsHashes(uint64(check), 1)
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// Wait until a reply arrives to this request
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for arrived := false; !arrived; {
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select {
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case <-d.cancelCh:
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return 0, errCancelHashFetch
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case hashPack := <-d.hashCh:
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// Discard anything not from the origin peer
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if hashPack.peerId != p.id {
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glog.V(logger.Debug).Infof("Received hashes from incorrect peer(%s)", hashPack.peerId)
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break
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}
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// Make sure the peer actually gave something valid
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hashes := hashPack.hashes
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if len(hashes) != 1 {
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glog.V(logger.Debug).Infof("%v: invalid search hash set (%d)", p, len(hashes))
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return 0, errBadPeer
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}
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arrived = true
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// Modify the search interval based on the response
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block := d.getBlock(hashes[0])
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if block == nil {
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end = check
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break
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}
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if block.NumberU64() != check {
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glog.V(logger.Debug).Infof("%v: non requested hash #%d [%x], instead of #%d", p, block.NumberU64(), block.Hash().Bytes()[:4], check)
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return 0, errBadPeer
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}
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start = check
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case <-d.blockCh:
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// Out of bounds blocks received, ignore them
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case <-timeout:
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glog.V(logger.Debug).Infof("%v: search hash timeout", p)
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return 0, errTimeout
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}
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}
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}
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return start, nil
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}
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// fetchHashes keeps retrieving hashes from the requested number, until no more
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// are returned, potentially throttling on the way.
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func (d *Downloader) fetchHashes(p *peer, td *big.Int, from uint64) error {
|
|
glog.V(logger.Debug).Infof("%v: downloading hashes from #%d", p, from)
|
|
|
|
// Create a timeout timer, and the associated hash fetcher
|
|
timeout := time.NewTimer(0) // timer to dump a non-responsive active peer
|
|
<-timeout.C // timeout channel should be initially empty
|
|
defer timeout.Stop()
|
|
|
|
getHashes := func(from uint64) {
|
|
glog.V(logger.Detail).Infof("%v: fetching %d hashes from #%d", p, MaxHashFetch, from)
|
|
|
|
go p.getAbsHashes(from, MaxHashFetch)
|
|
timeout.Reset(hashTTL)
|
|
}
|
|
// Start pulling hashes, until all are exhausted
|
|
getHashes(from)
|
|
gotHashes := false
|
|
|
|
for {
|
|
select {
|
|
case <-d.cancelCh:
|
|
return errCancelHashFetch
|
|
|
|
case hashPack := <-d.hashCh:
|
|
// Make sure the active peer is giving us the hashes
|
|
if hashPack.peerId != p.id {
|
|
glog.V(logger.Debug).Infof("Received hashes from incorrect peer(%s)", hashPack.peerId)
|
|
break
|
|
}
|
|
timeout.Stop()
|
|
|
|
// If no more hashes are inbound, notify the block fetcher and return
|
|
if len(hashPack.hashes) == 0 {
|
|
glog.V(logger.Debug).Infof("%v: no available hashes", p)
|
|
|
|
select {
|
|
case d.processCh <- false:
|
|
case <-d.cancelCh:
|
|
}
|
|
// If no hashes 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 hashes up from 11 (R's TD was higher, it must have something)
|
|
// R: Nothing to give
|
|
if !gotHashes && td.Cmp(d.headBlock().Td) > 0 {
|
|
return errStallingPeer
|
|
}
|
|
return nil
|
|
}
|
|
gotHashes = true
|
|
|
|
// Otherwise insert all the new hashes, aborting in case of junk
|
|
glog.V(logger.Detail).Infof("%v: inserting %d hashes from #%d", p, len(hashPack.hashes), from)
|
|
|
|
inserts := d.queue.Insert(hashPack.hashes, true)
|
|
if len(inserts) != len(hashPack.hashes) {
|
|
glog.V(logger.Debug).Infof("%v: stale hashes", p)
|
|
return errBadPeer
|
|
}
|
|
// Notify the block fetcher of new hashes, but stop if queue is full
|
|
cont := d.queue.Pending() < maxQueuedHashes
|
|
select {
|
|
case d.processCh <- cont:
|
|
default:
|
|
}
|
|
if !cont {
|
|
return nil
|
|
}
|
|
// Queue not yet full, fetch the next batch
|
|
from += uint64(len(hashPack.hashes))
|
|
getHashes(from)
|
|
|
|
case <-timeout.C:
|
|
glog.V(logger.Debug).Infof("%v: hash request timed out", p)
|
|
return errTimeout
|
|
}
|
|
}
|
|
}
|
|
|
|
// fetchBlocks iteratively downloads the scheduled hashes, taking any available
|
|
// peers, reserving a chunk of blocks for each, waiting for delivery and also
|
|
// periodically checking for timeouts.
|
|
func (d *Downloader) fetchBlocks(from uint64) error {
|
|
glog.V(logger.Debug).Infof("Downloading blocks from #%d", from)
|
|
defer glog.V(logger.Debug).Infof("Block download terminated")
|
|
|
|
// Create a timeout timer for scheduling expiration tasks
|
|
ticker := time.NewTicker(100 * time.Millisecond)
|
|
defer ticker.Stop()
|
|
|
|
update := make(chan struct{}, 1)
|
|
|
|
// Prepare the queue and fetch blocks until the hash fetcher's done
|
|
d.queue.Prepare(from)
|
|
finished := false
|
|
|
|
for {
|
|
select {
|
|
case <-d.cancelCh:
|
|
return errCancelBlockFetch
|
|
|
|
case blockPack := <-d.blockCh:
|
|
// 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(blockPack.peerId); peer != nil {
|
|
// Deliver the received chunk of blocks, and demote in case of errors
|
|
err := d.queue.Deliver(blockPack.peerId, blockPack.blocks)
|
|
switch err {
|
|
case nil:
|
|
// If no blocks were delivered, demote the peer (need the delivery above)
|
|
if len(blockPack.blocks) == 0 {
|
|
peer.Demote()
|
|
peer.SetIdle()
|
|
glog.V(logger.Detail).Infof("%s: no blocks delivered", peer)
|
|
break
|
|
}
|
|
// All was successful, promote the peer and potentially start processing
|
|
peer.Promote()
|
|
peer.SetIdle()
|
|
glog.V(logger.Detail).Infof("%s: delivered %d blocks", peer, len(blockPack.blocks))
|
|
go d.process()
|
|
|
|
case errInvalidChain:
|
|
// The hash chain is invalid (blocks are not ordered properly), abort
|
|
return err
|
|
|
|
case errNoFetchesPending:
|
|
// Peer probably timed out with its delivery but came through
|
|
// in the end, demote, but allow to to pull from this peer.
|
|
peer.Demote()
|
|
peer.SetIdle()
|
|
glog.V(logger.Detail).Infof("%s: out of bound delivery", peer)
|
|
|
|
case errStaleDelivery:
|
|
// Delivered something completely else than requested, usually
|
|
// caused by a timeout and delivery during a new sync cycle.
|
|
// Don't set it to idle as the original request should still be
|
|
// in flight.
|
|
peer.Demote()
|
|
glog.V(logger.Detail).Infof("%s: stale delivery", peer)
|
|
|
|
default:
|
|
// Peer did something semi-useful, demote but keep it around
|
|
peer.Demote()
|
|
peer.SetIdle()
|
|
glog.V(logger.Detail).Infof("%s: delivery partially failed: %v", peer, err)
|
|
go d.process()
|
|
}
|
|
}
|
|
// Blocks arrived, try to update the progress
|
|
select {
|
|
case update <- struct{}{}:
|
|
default:
|
|
}
|
|
|
|
case cont := <-d.processCh:
|
|
// The hash fetcher sent a continuation flag, check if it's done
|
|
if !cont {
|
|
finished = true
|
|
}
|
|
// Hashes 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 block request timeouts and demote the responsible peers
|
|
for _, pid := range d.queue.Expire(blockHardTTL) {
|
|
if peer := d.peers.Peer(pid); peer != nil {
|
|
peer.Demote()
|
|
glog.V(logger.Detail).Infof("%s: block delivery timeout", peer)
|
|
}
|
|
}
|
|
// If there's noting more to fetch, wait or terminate
|
|
if d.queue.Pending() == 0 {
|
|
if d.queue.InFlight() == 0 && finished {
|
|
glog.V(logger.Debug).Infof("Block fetching completed")
|
|
return nil
|
|
}
|
|
break
|
|
}
|
|
// Send a download request to all idle peers, until throttled
|
|
for _, peer := range d.peers.IdlePeers() {
|
|
// Short circuit if throttling activated
|
|
if d.queue.Throttle() {
|
|
break
|
|
}
|
|
// Reserve a chunk of hashes for a peer. A nil can mean either that
|
|
// no more hashes are available, or that the peer is known not to
|
|
// have them.
|
|
request := d.queue.Reserve(peer, peer.Capacity())
|
|
if request == nil {
|
|
continue
|
|
}
|
|
if glog.V(logger.Detail) {
|
|
glog.Infof("%s: requesting %d blocks", peer, len(request.Hashes))
|
|
}
|
|
// Fetch the chunk and make sure any errors return the hashes to the queue
|
|
if err := peer.Fetch(request); err != nil {
|
|
glog.V(logger.Error).Infof("%v: fetch failed, rescheduling", peer)
|
|
d.queue.Cancel(request)
|
|
}
|
|
}
|
|
// Make sure that we have peers available for fetching. If all peers have been tried
|
|
// and all failed throw an error
|
|
if !d.queue.Throttle() && d.queue.InFlight() == 0 {
|
|
return errPeersUnavailable
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// process takes blocks from the queue and tries to import them into the chain.
|
|
//
|
|
// The algorithmic flow is as follows:
|
|
// - The `processing` flag is swapped to 1 to ensure singleton access
|
|
// - The current `cancel` channel is retrieved to detect sync abortions
|
|
// - Blocks are iteratively taken from the cache and inserted into the chain
|
|
// - When the cache becomes empty, insertion stops
|
|
// - The `processing` flag is swapped back to 0
|
|
// - A post-exit check is made whether new blocks became available
|
|
// - This step is important: it handles a potential race condition between
|
|
// checking for no more work, and releasing the processing "mutex". In
|
|
// between these state changes, a block may have arrived, but a processing
|
|
// attempt denied, so we need to re-enter to ensure the block isn't left
|
|
// to idle in the cache.
|
|
func (d *Downloader) process() {
|
|
// Make sure only one goroutine is ever allowed to process blocks at once
|
|
if !atomic.CompareAndSwapInt32(&d.processing, 0, 1) {
|
|
return
|
|
}
|
|
// If the processor just exited, but there are freshly pending items, try to
|
|
// reenter. This is needed because the goroutine spinned up for processing
|
|
// the fresh blocks might have been rejected entry to to this present thread
|
|
// not yet releasing the `processing` state.
|
|
defer func() {
|
|
if atomic.LoadInt32(&d.interrupt) == 0 && d.queue.GetHeadBlock() != nil {
|
|
d.process()
|
|
}
|
|
}()
|
|
// Release the lock upon exit (note, before checking for reentry!), and set
|
|
// the import statistics to zero.
|
|
defer func() {
|
|
d.importLock.Lock()
|
|
d.importQueue = nil
|
|
d.importDone = 0
|
|
d.importLock.Unlock()
|
|
|
|
atomic.StoreInt32(&d.processing, 0)
|
|
}()
|
|
// Repeat the processing as long as there are blocks to import
|
|
for {
|
|
// Fetch the next batch of blocks
|
|
blocks := d.queue.TakeBlocks()
|
|
if len(blocks) == 0 {
|
|
return
|
|
}
|
|
// Reset the import statistics
|
|
d.importLock.Lock()
|
|
d.importStart = time.Now()
|
|
d.importQueue = blocks
|
|
d.importDone = 0
|
|
d.importLock.Unlock()
|
|
|
|
// Actually import the blocks
|
|
glog.V(logger.Debug).Infof("Inserting chain with %d blocks (#%v - #%v)\n", len(blocks), blocks[0].RawBlock.Number(), blocks[len(blocks)-1].RawBlock.Number())
|
|
for len(blocks) != 0 {
|
|
// Check for any termination requests
|
|
if atomic.LoadInt32(&d.interrupt) == 1 {
|
|
return
|
|
}
|
|
// Retrieve the first batch of blocks to insert
|
|
max := int(math.Min(float64(len(blocks)), float64(maxBlockProcess)))
|
|
raw := make(types.Blocks, 0, max)
|
|
for _, block := range blocks[:max] {
|
|
raw = append(raw, block.RawBlock)
|
|
}
|
|
// Try to inset the blocks, drop the originating peer if there's an error
|
|
index, err := d.insertChain(raw)
|
|
if err != nil {
|
|
glog.V(logger.Debug).Infof("Block #%d import failed: %v", raw[index].NumberU64(), err)
|
|
d.dropPeer(blocks[index].OriginPeer)
|
|
d.cancel()
|
|
return
|
|
}
|
|
blocks = blocks[max:]
|
|
}
|
|
}
|
|
}
|
|
|
|
// DeliverBlocks injects a new batch of blocks received from a remote node.
|
|
// This is usually invoked through the BlocksMsg by the protocol handler.
|
|
func (d *Downloader) DeliverBlocks(id string, blocks []*types.Block) error {
|
|
// Make sure the downloader is active
|
|
if atomic.LoadInt32(&d.synchronising) == 0 {
|
|
return errNoSyncActive
|
|
}
|
|
// Deliver or abort if the sync is canceled while queuing
|
|
d.cancelLock.RLock()
|
|
cancel := d.cancelCh
|
|
d.cancelLock.RUnlock()
|
|
|
|
select {
|
|
case d.blockCh <- blockPack{id, blocks}:
|
|
return nil
|
|
|
|
case <-cancel:
|
|
return errNoSyncActive
|
|
}
|
|
}
|
|
|
|
// DeliverHashes injects a new batch of hashes received from a remote node into
|
|
// the download schedule. This is usually invoked through the BlockHashesMsg by
|
|
// the protocol handler.
|
|
func (d *Downloader) DeliverHashes(id string, hashes []common.Hash) error {
|
|
// Make sure the downloader is active
|
|
if atomic.LoadInt32(&d.synchronising) == 0 {
|
|
return errNoSyncActive
|
|
}
|
|
// Deliver or abort if the sync is canceled while queuing
|
|
d.cancelLock.RLock()
|
|
cancel := d.cancelCh
|
|
d.cancelLock.RUnlock()
|
|
|
|
select {
|
|
case d.hashCh <- hashPack{id, hashes}:
|
|
return nil
|
|
|
|
case <-cancel:
|
|
return errNoSyncActive
|
|
}
|
|
}
|