mirror of https://github.com/poanetwork/quorum.git
447 lines
14 KiB
Go
447 lines
14 KiB
Go
package downloader
|
|
|
|
import (
|
|
"errors"
|
|
"fmt"
|
|
"sync"
|
|
"sync/atomic"
|
|
"time"
|
|
|
|
"github.com/ethereum/go-ethereum/common"
|
|
"github.com/ethereum/go-ethereum/core/types"
|
|
"github.com/ethereum/go-ethereum/logger"
|
|
"github.com/ethereum/go-ethereum/logger/glog"
|
|
)
|
|
|
|
const (
|
|
maxBlockFetch = 128 // Amount of max blocks to be fetched per chunk
|
|
peerCountTimeout = 12 * time.Second // Amount of time it takes for the peer handler to ignore minDesiredPeerCount
|
|
hashTtl = 20 * time.Second // The amount of time it takes for a hash request to time out
|
|
)
|
|
|
|
var (
|
|
minDesiredPeerCount = 5 // Amount of peers desired to start syncing
|
|
blockTtl = 20 * time.Second // The amount of time it takes for a block request to time out
|
|
|
|
errLowTd = errors.New("peer's TD is too low")
|
|
ErrBusy = errors.New("busy")
|
|
errUnknownPeer = errors.New("peer's unknown or unhealthy")
|
|
errBadPeer = errors.New("action from bad peer ignored")
|
|
errNoPeers = errors.New("no peers to keep download active")
|
|
errPendingQueue = errors.New("pending items in queue")
|
|
ErrTimeout = errors.New("timeout")
|
|
errEmptyHashSet = errors.New("empty hash set by peer")
|
|
errPeersUnavailable = errors.New("no peers available or all peers tried for block download process")
|
|
errAlreadyInPool = errors.New("hash already in pool")
|
|
errBlockNumberOverflow = errors.New("received block which overflows")
|
|
errCancelHashFetch = errors.New("hash fetching cancelled (requested)")
|
|
errCancelBlockFetch = errors.New("block downloading cancelled (requested)")
|
|
errNoSyncActive = errors.New("no sync active")
|
|
)
|
|
|
|
type hashCheckFn func(common.Hash) bool
|
|
type getBlockFn func(common.Hash) *types.Block
|
|
type chainInsertFn func(types.Blocks) (int, error)
|
|
type hashIterFn func() (common.Hash, error)
|
|
|
|
type blockPack struct {
|
|
peerId string
|
|
blocks []*types.Block
|
|
}
|
|
|
|
type hashPack struct {
|
|
peerId string
|
|
hashes []common.Hash
|
|
}
|
|
|
|
type Downloader struct {
|
|
mu sync.RWMutex
|
|
queue *queue
|
|
peers *peerSet
|
|
activePeer string
|
|
|
|
// Callbacks
|
|
hasBlock hashCheckFn
|
|
getBlock getBlockFn
|
|
|
|
// Status
|
|
synchronising int32
|
|
|
|
// Channels
|
|
newPeerCh chan *peer
|
|
hashCh chan hashPack
|
|
blockCh chan blockPack
|
|
cancelCh chan struct{}
|
|
}
|
|
|
|
func New(hasBlock hashCheckFn, getBlock getBlockFn) *Downloader {
|
|
downloader := &Downloader{
|
|
queue: newQueue(),
|
|
peers: newPeerSet(),
|
|
hasBlock: hasBlock,
|
|
getBlock: getBlock,
|
|
newPeerCh: make(chan *peer, 1),
|
|
hashCh: make(chan hashPack, 1),
|
|
blockCh: make(chan blockPack, 1),
|
|
}
|
|
|
|
return downloader
|
|
}
|
|
|
|
func (d *Downloader) Stats() (current int, max int) {
|
|
return d.queue.Size()
|
|
}
|
|
|
|
// 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, head common.Hash, getHashes hashFetcherFn, getBlocks blockFetcherFn) error {
|
|
glog.V(logger.Detail).Infoln("Registering peer", id)
|
|
if err := d.peers.Register(newPeer(id, head, getHashes, getBlocks)); err != nil {
|
|
glog.V(logger.Error).Infoln("Register failed:", err)
|
|
return err
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// UnregisterPeer remove a peer from the known list, preventing any action from
|
|
// the specified peer.
|
|
func (d *Downloader) UnregisterPeer(id string) error {
|
|
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
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// 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) error {
|
|
// 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)
|
|
|
|
// Create cancel channel for aborting midflight
|
|
d.cancelCh = make(chan struct{})
|
|
|
|
// Abort if the queue still contains some leftover data
|
|
if _, cached := d.queue.Size(); cached > 0 && d.queue.GetHeadBlock() != nil {
|
|
return errPendingQueue
|
|
}
|
|
// Reset the queue and peer set to clean any internal leftover state
|
|
d.queue.Reset()
|
|
d.peers.Reset()
|
|
|
|
// Retrieve the origin peer and initiate the downloading process
|
|
p := d.peers.Peer(id)
|
|
if p == nil {
|
|
return errUnknownPeer
|
|
}
|
|
return d.syncWithPeer(p, hash)
|
|
}
|
|
|
|
// TakeBlocks takes blocks from the queue and yields them to the blockTaker handler
|
|
// it's possible it yields no blocks
|
|
func (d *Downloader) TakeBlocks() types.Blocks {
|
|
// Check that there are blocks available and its parents are known
|
|
head := d.queue.GetHeadBlock()
|
|
if head == nil || !d.hasBlock(head.ParentHash()) {
|
|
return nil
|
|
}
|
|
// Retrieve a full batch of blocks
|
|
return d.queue.TakeBlocks(head)
|
|
}
|
|
|
|
func (d *Downloader) Has(hash common.Hash) bool {
|
|
return d.queue.Has(hash)
|
|
}
|
|
|
|
// 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) (err error) {
|
|
d.activePeer = p.id
|
|
defer func() {
|
|
// reset on error
|
|
if err != nil {
|
|
d.queue.Reset()
|
|
}
|
|
}()
|
|
|
|
glog.V(logger.Debug).Infoln("Synchronizing with the network using:", p.id)
|
|
if err = d.fetchHashes(p, hash); err != nil {
|
|
return err
|
|
}
|
|
if err = d.fetchBlocks(); err != nil {
|
|
return err
|
|
}
|
|
glog.V(logger.Debug).Infoln("Synchronization completed")
|
|
|
|
return nil
|
|
}
|
|
|
|
// Cancel cancels all of the operations and resets the queue. It returns true
|
|
// if the cancel operation was completed.
|
|
func (d *Downloader) Cancel() bool {
|
|
hs, bs := d.queue.Size()
|
|
// If we're not syncing just return.
|
|
if atomic.LoadInt32(&d.synchronising) == 0 && hs == 0 && bs == 0 {
|
|
return false
|
|
}
|
|
|
|
close(d.cancelCh)
|
|
|
|
// clean up
|
|
hashDone:
|
|
for {
|
|
select {
|
|
case <-d.hashCh:
|
|
default:
|
|
break hashDone
|
|
}
|
|
}
|
|
|
|
blockDone:
|
|
for {
|
|
select {
|
|
case <-d.blockCh:
|
|
default:
|
|
break blockDone
|
|
}
|
|
}
|
|
|
|
// reset the queue
|
|
d.queue.Reset()
|
|
|
|
return true
|
|
}
|
|
|
|
// XXX Make synchronous
|
|
func (d *Downloader) fetchHashes(p *peer, h common.Hash) error {
|
|
glog.V(logger.Debug).Infof("Downloading hashes (%x) from %s", h[:4], p.id)
|
|
|
|
start := time.Now()
|
|
|
|
// Add the hash to the queue first
|
|
d.queue.Insert([]common.Hash{h})
|
|
|
|
// Get the first batch of hashes
|
|
p.getHashes(h)
|
|
|
|
var (
|
|
failureResponseTimer = time.NewTimer(hashTtl)
|
|
attemptedPeers = make(map[string]bool) // attempted peers will help with retries
|
|
activePeer = p // active peer will help determine the current active peer
|
|
hash common.Hash // common and last hash
|
|
)
|
|
attemptedPeers[p.id] = true
|
|
|
|
out:
|
|
for {
|
|
select {
|
|
case <-d.cancelCh:
|
|
return errCancelHashFetch
|
|
case hashPack := <-d.hashCh:
|
|
// Make sure the active peer is giving us the hashes
|
|
if hashPack.peerId != activePeer.id {
|
|
glog.V(logger.Debug).Infof("Received hashes from incorrect peer(%s)\n", hashPack.peerId)
|
|
break
|
|
}
|
|
|
|
failureResponseTimer.Reset(hashTtl)
|
|
|
|
// Make sure the peer actually gave something valid
|
|
if len(hashPack.hashes) == 0 {
|
|
glog.V(logger.Debug).Infof("Peer (%s) responded with empty hash set\n", activePeer.id)
|
|
d.queue.Reset()
|
|
|
|
return errEmptyHashSet
|
|
}
|
|
// Determine if we're done fetching hashes (queue up all pending), and continue if not done
|
|
done, index := false, 0
|
|
for index, hash = range hashPack.hashes {
|
|
if d.hasBlock(hash) || d.queue.GetBlock(hash) != nil {
|
|
glog.V(logger.Debug).Infof("Found common hash %x\n", hash[:4])
|
|
hashPack.hashes = hashPack.hashes[:index]
|
|
done = true
|
|
break
|
|
}
|
|
}
|
|
d.queue.Insert(hashPack.hashes)
|
|
|
|
if !done {
|
|
activePeer.getHashes(hash)
|
|
continue
|
|
}
|
|
// We're done, allocate the download cache and proceed pulling the blocks
|
|
offset := 0
|
|
if block := d.getBlock(hash); block != nil {
|
|
offset = int(block.NumberU64() + 1)
|
|
}
|
|
d.queue.Alloc(offset)
|
|
break out
|
|
|
|
case <-failureResponseTimer.C:
|
|
glog.V(logger.Debug).Infof("Peer (%s) didn't respond in time for hash request\n", p.id)
|
|
|
|
var p *peer // p will be set if a peer can be found
|
|
// Attempt to find a new peer by checking inclusion of peers best hash in our
|
|
// already fetched hash list. This can't guarantee 100% correctness but does
|
|
// a fair job. This is always either correct or false incorrect.
|
|
for _, peer := range d.peers.AllPeers() {
|
|
if d.queue.Has(peer.head) && !attemptedPeers[p.id] {
|
|
p = peer
|
|
break
|
|
}
|
|
}
|
|
// if all peers have been tried, abort the process entirely or if the hash is
|
|
// the zero hash.
|
|
if p == nil || (hash == common.Hash{}) {
|
|
d.queue.Reset()
|
|
return ErrTimeout
|
|
}
|
|
// set p to the active peer. this will invalidate any hashes that may be returned
|
|
// by our previous (delayed) peer.
|
|
activePeer = p
|
|
p.getHashes(hash)
|
|
glog.V(logger.Debug).Infof("Hash fetching switched to new peer(%s)\n", p.id)
|
|
}
|
|
}
|
|
glog.V(logger.Debug).Infof("Downloaded hashes (%d) in %v\n", d.queue.Pending(), time.Since(start))
|
|
|
|
return nil
|
|
}
|
|
|
|
// fetchBlocks iteratively downloads the entire schedules block-chain, taking
|
|
// any available peers, reserving a chunk of blocks for each, wait for delivery
|
|
// and periodically checking for timeouts.
|
|
func (d *Downloader) fetchBlocks() error {
|
|
glog.V(logger.Debug).Infoln("Downloading", d.queue.Pending(), "block(s)")
|
|
start := time.Now()
|
|
|
|
// default ticker for re-fetching blocks every now and then
|
|
ticker := time.NewTicker(20 * time.Millisecond)
|
|
out:
|
|
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, but drop the peer if invalid
|
|
if err := d.queue.Deliver(blockPack.peerId, blockPack.blocks); err != nil {
|
|
glog.V(logger.Debug).Infof("Failed delivery for peer %s: %v\n", blockPack.peerId, err)
|
|
d.peers.Unregister(blockPack.peerId)
|
|
break
|
|
}
|
|
if glog.V(logger.Debug) {
|
|
glog.Infof("Added %d blocks from: %s\n", len(blockPack.blocks), blockPack.peerId)
|
|
}
|
|
// Promote the peer and update it's idle state
|
|
peer.Promote()
|
|
peer.SetIdle()
|
|
}
|
|
case <-ticker.C:
|
|
// Check for bad peers. Bad peers may indicate a peer not responding
|
|
// to a `getBlocks` message. A timeout of 5 seconds is set. Peers
|
|
// that badly or poorly behave are removed from the peer set (not banned).
|
|
// Bad peers are excluded from the available peer set and therefor won't be
|
|
// reused. XXX We could re-introduce peers after X time.
|
|
badPeers := d.queue.Expire(blockTtl)
|
|
for _, pid := range badPeers {
|
|
// XXX We could make use of a reputation system here ranking peers
|
|
// in their performance
|
|
// 1) Time for them to respond;
|
|
// 2) Measure their speed;
|
|
// 3) Amount and availability.
|
|
d.peers.Unregister(pid)
|
|
}
|
|
// After removing bad peers make sure we actually have sufficient peer left to keep downloading
|
|
if d.peers.Peers() == 0 {
|
|
d.queue.Reset()
|
|
return errNoPeers
|
|
}
|
|
// If there are unrequested hashes left start fetching
|
|
// from the available peers.
|
|
if d.queue.Pending() > 0 {
|
|
// Throttle the download if block cache is full and waiting processing
|
|
if d.queue.Throttle() {
|
|
continue
|
|
}
|
|
// Send a download request to all idle peers
|
|
idlePeers := d.peers.IdlePeers()
|
|
for _, peer := range idlePeers {
|
|
// Get a possible chunk. If nil is returned no chunk
|
|
// could be returned due to no hashes available.
|
|
request := d.queue.Reserve(peer, maxBlockFetch)
|
|
if request == nil {
|
|
continue
|
|
}
|
|
// Fetch the chunk and check for error. If the peer was somehow
|
|
// already fetching a chunk due to a bug, it will be returned to
|
|
// the queue
|
|
if err := peer.Fetch(request); err != nil {
|
|
glog.V(logger.Error).Infof("Peer %s received double work\n", peer.id)
|
|
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.InFlight() == 0 {
|
|
d.queue.Reset()
|
|
|
|
return fmt.Errorf("%v peers available = %d. total peers = %d. hashes needed = %d", errPeersUnavailable, len(idlePeers), d.peers.Peers(), d.queue.Pending())
|
|
}
|
|
|
|
} else if d.queue.InFlight() == 0 {
|
|
// When there are no more queue and no more in flight, We can
|
|
// safely assume we're done. Another part of the process will check
|
|
// for parent errors and will re-request anything that's missing
|
|
break out
|
|
}
|
|
}
|
|
}
|
|
glog.V(logger.Detail).Infoln("Downloaded block(s) in", time.Since(start))
|
|
|
|
return nil
|
|
}
|
|
|
|
// Deliver a chunk to the downloader. This is usually done through the BlocksMsg by
|
|
// the protocol handler.
|
|
func (d *Downloader) DeliverChunk(id string, blocks []*types.Block) error {
|
|
// Make sure the downloader is active
|
|
if atomic.LoadInt32(&d.synchronising) == 0 {
|
|
return errNoSyncActive
|
|
}
|
|
|
|
d.blockCh <- blockPack{id, blocks}
|
|
|
|
return nil
|
|
}
|
|
|
|
func (d *Downloader) AddHashes(id string, hashes []common.Hash) error {
|
|
// Make sure the downloader is active
|
|
if atomic.LoadInt32(&d.synchronising) == 0 {
|
|
return errNoSyncActive
|
|
}
|
|
|
|
// make sure that the hashes that are being added are actually from the peer
|
|
// that's the current active peer. hashes that have been received from other
|
|
// peers are dropped and ignored.
|
|
if d.activePeer != id {
|
|
return fmt.Errorf("received hashes from %s while active peer is %s", id, d.activePeer)
|
|
}
|
|
|
|
if glog.V(logger.Debug) && len(hashes) != 0 {
|
|
from, to := hashes[0], hashes[len(hashes)-1]
|
|
glog.V(logger.Debug).Infof("adding %d (T=%d) hashes [ %x / %x ] from: %s\n", len(hashes), d.queue.Pending(), from[:4], to[:4], id)
|
|
}
|
|
d.hashCh <- hashPack{id, hashes}
|
|
|
|
return nil
|
|
}
|