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downloader: added missing blocks catchup functionality

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When a parent is missing in the block list an attempt should be made to
fetch the missing parent and grandparents.
This commit is contained in:
obscuren 2015-04-13 16:38:32 +02:00
parent 7dcb9825c3
commit a8a2b2a488
4 changed files with 304 additions and 134 deletions
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313
eth/downloader/downloader.go
View File

@ -8,63 +8,44 @@ import (
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/logger"
"github.com/ethereum/go-ethereum/logger/glog"
"gopkg.in/fatih/set.v0"
)
const maxBlockFetch = 256
const (
maxBlockFetch = 256 // Amount of max blocks to be fetched per chunk
minDesiredPeerCount = 3 // Amount of peers desired to start syncing
)
type hashFetcherFn func(common.Hash) error
type blockFetcherFn func([]common.Hash) error
type hashCheckFn func(common.Hash) bool
type chainInsertFn func(types.Blocks) error
type hashIterFn func() (common.Hash, error)
// XXX make threadsafe!!!!
type peers map[string]*peer
func (p peers) get(state int) []*peer {
var peers []*peer
for _, peer := range p {
peer.mu.RLock()
if peer.state == state {
peers = append(peers, peer)
}
peer.mu.RUnlock()
}
return peers
}
func (p peers) setState(id string, state int) {
if peer, exist := p[id]; exist {
peer.mu.Lock()
defer peer.mu.Unlock()
peer.state = state
}
}
type currentTdFn func() *big.Int
type Downloader struct {
queue *queue
hasBlock hashCheckFn
insertChain chainInsertFn
mu sync.RWMutex
queue *queue
peers peers
currentPeer *peer
// Callbacks
hasBlock hashCheckFn
insertChain chainInsertFn
currentTd currentTdFn
// Status
fetchingHashes int32
downloadingBlocks int32
processingBlocks int32
newPeerCh chan *peer
selectPeerCh chan *peer
HashCh chan []common.Hash
blockCh chan blockPack
quit chan struct{}
// Channels
newPeerCh chan *peer
syncCh chan syncPack
HashCh chan []common.Hash
blockCh chan blockPack
quit chan struct{}
}
type blockPack struct {
@ -72,17 +53,23 @@ type blockPack struct {
blocks []*types.Block
}
func New(hasBlock hashCheckFn, insertChain chainInsertFn) *Downloader {
type syncPack struct {
peer *peer
hash common.Hash
}
func New(hasBlock hashCheckFn, insertChain chainInsertFn, currentTd currentTdFn) *Downloader {
downloader := &Downloader{
queue: newqueue(),
peers: make(peers),
hasBlock: hasBlock,
insertChain: insertChain,
newPeerCh: make(chan *peer, 1),
selectPeerCh: make(chan *peer, 1),
HashCh: make(chan []common.Hash, 1),
blockCh: make(chan blockPack, 1),
quit: make(chan struct{}),
queue: newqueue(),
peers: make(peers),
hasBlock: hasBlock,
insertChain: insertChain,
currentTd: currentTd,
newPeerCh: make(chan *peer, 1),
syncCh: make(chan syncPack, 1),
HashCh: make(chan []common.Hash, 1),
blockCh: make(chan blockPack, 1),
quit: make(chan struct{}),
}
go downloader.peerHandler()
go downloader.update()
@ -116,89 +103,88 @@ func (d *Downloader) UnregisterPeer(id string) {
}
func (d *Downloader) peerHandler() {
// Fields defined here so we can reduce the amount of locking
// that needs to be done
var highestTd = new(big.Int)
// itimer is used to determine when to start ignoring `minDesiredPeerCount`
itimer := time.NewTicker(5 * time.Second)
out:
for {
select {
case newPeer := <-d.newPeerCh:
// Check if TD of peer is higher than our current
if newPeer.td.Cmp(highestTd) > 0 {
glog.V(logger.Detail).Infoln("New peer with highest TD =", newPeer.td)
highestTd.Set(newPeer.td)
// select the peer for downloading
d.selectPeerCh <- newPeer
case <-d.newPeerCh:
// Meet the `minDesiredPeerCount` before we select our best peer
if len(d.peers) < minDesiredPeerCount {
break
}
d.selectPeer(d.peers.bestPeer())
case <-itimer.C:
// The timer will make sure that the downloader keeps an active state
// in which it attempts to always check the network for highest td peers
d.selectPeer(d.peers.bestPeer())
case <-d.quit:
break out
}
}
}
func (d *Downloader) selectPeer(p *peer) {
// Make sure it's doing neither. Once done we can restart the
// downloading process if the TD is higher. For now just get on
// with whatever is going on. This prevents unecessary switching.
if !(d.isFetchingHashes() || d.isDownloadingBlocks() || d.isProcessing()) {
// selected peer must be better than our own
// XXX we also check the peer's recent hash to make sure we
// don't have it. Some peers report (i think) incorrect TD.
if p.td.Cmp(d.currentTd()) <= 0 || d.hasBlock(p.recentHash) {
return
}
glog.V(logger.Detail).Infoln("New peer with highest TD =", p.td)
d.syncCh <- syncPack{p, p.recentHash}
}
}
func (d *Downloader) update() {
out:
for {
select {
case selectedPeer := <-d.selectPeerCh:
// Make sure it's doing neither. Once done we can restart the
// downloading process if the TD is higher. For now just get on
// with whatever is going on. This prevents unecessary switching.
if !(d.isFetchingHashes() || d.isDownloadingBlocks()) {
glog.V(logger.Detail).Infoln("Selected new peer", selectedPeer.id)
// Start the fetcher. This will block the update entirely
// interupts need to be send to the appropriate channels
// respectively.
if err := d.startFetchingHashes(selectedPeer); err != nil {
// handle error
glog.V(logger.Debug).Infoln("Error fetching hashes:", err)
// Reset
break
}
// Start fetching blocks in paralel. The strategy is simple
// take any available peers, seserve a chunk for each peer available,
// let the peer deliver the chunkn and periodically check if a peer
// has timedout. When done downloading, process blocks.
if err := d.startFetchingBlocks(selectedPeer); err != nil {
glog.V(logger.Debug).Infoln("Error downloading blocks:", err)
// reset
break
}
// XXX this will move when optimised
// Sort the blocks by number. This bit needs much improvement. Right now
// it assumes full honesty form peers (i.e. it's not checked when the blocks
// link). We should at least check whihc queue match. This code could move
// to a seperate goroutine where it periodically checks for linked pieces.
types.BlockBy(types.Number).Sort(d.queue.blocks)
blocks := d.queue.blocks
glog.V(logger.Debug).Infoln("Inserting chain with", len(blocks), "blocks")
// Loop untill we're out of queue
for len(blocks) != 0 {
max := int(math.Min(float64(len(blocks)), 256))
// TODO check for parent error. When there's a parent error we should stop
// processing and start requesting the `block.hash` so that it's parent and
// grandparents can be requested and queued.
d.insertChain(blocks[:max])
blocks = blocks[max:]
}
case sync := <-d.syncCh:
selectedPeer := sync.peer
glog.V(logger.Detail).Infoln("Synchronising with network using:", selectedPeer.id)
// Start the fetcher. This will block the update entirely
// interupts need to be send to the appropriate channels
// respectively.
if err := d.startFetchingHashes(selectedPeer, sync.hash); err != nil {
// handle error
glog.V(logger.Debug).Infoln("Error fetching hashes:", err)
// XXX Reset
break
}
// Start fetching blocks in paralel. The strategy is simple
// take any available peers, seserve a chunk for each peer available,
// let the peer deliver the chunkn and periodically check if a peer
// has timedout. When done downloading, process blocks.
if err := d.startFetchingBlocks(selectedPeer); err != nil {
glog.V(logger.Debug).Infoln("Error downloading blocks:", err)
// XXX reset
break
}
glog.V(logger.Detail).Infoln("Sync completed")
d.process()
case <-d.quit:
break out
}
}
}
func (d *Downloader) startFetchingHashes(p *peer) error {
// XXX Make synchronous
func (d *Downloader) startFetchingHashes(p *peer, hash common.Hash) error {
glog.V(logger.Debug).Infoln("Downloading hashes")
start := time.Now()
// Get the first batch of hashes
p.getHashes(p.recentHash)
p.getHashes(hash)
atomic.StoreInt32(&d.fetchingHashes, 1)
out:
@ -237,10 +223,6 @@ out:
return nil
}
func (d *Downloader) DeliverBlocks(id string, block []*types.Block) {
d.blockCh <- blockPack{id, block}
}
func (d *Downloader) startFetchingBlocks(p *peer) error {
glog.V(logger.Detail).Infoln("Downloading", d.queue.hashPool.Size(), "blocks")
atomic.StoreInt32(&d.downloadingBlocks, 1)
@ -253,8 +235,6 @@ out:
for {
select {
case blockPack := <-d.blockCh:
//fmt.Println("get for", blockPack.peerId)
d.queue.deliver(blockPack.peerId, blockPack.blocks)
d.peers.setState(blockPack.peerId, idleState)
case <-ticker.C:
@ -266,21 +246,24 @@ out:
// Get a possible chunk. If nil is returned no chunk
// could be returned due to no hashes available.
chunk := d.queue.get(peer, maxBlockFetch)
if chunk != nil {
//fmt.Println("fetching for", peer.id)
// 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(chunk); err != nil {
// log for tracing
glog.V(logger.Debug).Infof("peer %s received double work (state = %v)\n", peer.id, peer.state)
d.queue.put(chunk.hashes)
}
if chunk == nil {
continue
}
//fmt.Println("fetching for", peer.id)
// XXX make fetch blocking.
// 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(chunk); err != nil {
// log for tracing
glog.V(logger.Debug).Infof("peer %s received double work (state = %v)\n", peer.id, peer.state)
d.queue.put(chunk.hashes)
}
}
atomic.StoreInt32(&d.downloadingBlocks, 1)
} else if len(d.queue.fetching) == 0 {
// Whene there are no more queue and no more `fetching`. We can
// When there are no more queue and no more `fetching`. 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
atomic.StoreInt32(&d.downloadingBlocks, 0)
@ -325,6 +308,88 @@ out:
return nil
}
// Add an (unrequested) block to the downloader. This is usually done through the
// NewBlockMsg by the protocol handler.
func (d *Downloader) AddBlock(id string, block *types.Block, td *big.Int) {
hash := block.Hash()
if d.hasBlock(hash) {
return
}
glog.V(logger.Detail).Infoln("Inserting new block from:", id)
d.queue.addBlock(id, block, td)
// if the peer is in our healthy list of peers; update the td
// here is a good chance to add the peer back to the list
if peer := d.peers.getPeer(id); peer != nil {
peer.mu.Lock()
peer.td = td
peer.recentHash = block.Hash()
peer.mu.Unlock()
}
// if neither go ahead to process
if !(d.isFetchingHashes() || d.isDownloadingBlocks()) {
d.process()
}
}
// 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) {
d.blockCh <- blockPack{id, blocks}
}
func (d *Downloader) process() error {
atomic.StoreInt32(&d.processingBlocks, 1)
defer atomic.StoreInt32(&d.processingBlocks, 0)
// XXX this will move when optimised
// Sort the blocks by number. This bit needs much improvement. Right now
// it assumes full honesty form peers (i.e. it's not checked when the blocks
// link). We should at least check whihc queue match. This code could move
// to a seperate goroutine where it periodically checks for linked pieces.
types.BlockBy(types.Number).Sort(d.queue.blocks)
blocks := d.queue.blocks
glog.V(logger.Debug).Infoln("Inserting chain with", len(blocks), "blocks")
var err error
// Loop untill we're out of blocks
for len(blocks) != 0 {
max := int(math.Min(float64(len(blocks)), 256))
// TODO check for parent error. When there's a parent error we should stop
// processing and start requesting the `block.hash` so that it's parent and
// grandparents can be requested and queued.
err = d.insertChain(blocks[:max])
if err != nil && core.IsParentErr(err) {
glog.V(logger.Debug).Infoln("Aborting process due to missing parent. Fetching hashes")
// TODO change this. This shite
for i, block := range blocks[:max] {
if !d.hasBlock(block.ParentHash()) {
d.syncCh <- syncPack{d.peers.bestPeer(), block.Hash()}
// remove processed blocks
blocks = blocks[i:]
break
}
}
break
}
blocks = blocks[max:]
}
// This will allow the GC to remove the in memory blocks
if len(blocks) == 0 {
d.queue.blocks = nil
} else {
d.queue.blocks = blocks
}
return err
}
func (d *Downloader) isFetchingHashes() bool {
return atomic.LoadInt32(&d.fetchingHashes) == 1
}
@ -332,3 +397,7 @@ func (d *Downloader) isFetchingHashes() bool {
func (d *Downloader) isDownloadingBlocks() bool {
return atomic.LoadInt32(&d.downloadingBlocks) == 1
}
func (d *Downloader) isProcessing() bool {
return atomic.LoadInt32(&d.processingBlocks) == 1
}

37
eth/downloader/downloader_test.go
View File

@ -14,7 +14,7 @@ import (
var knownHash = common.Hash{1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
func createHashes(amount int) (hashes []common.Hash) {
func createHashes(start, amount int) (hashes []common.Hash) {
hashes = make([]common.Hash, amount+1)
hashes[len(hashes)-1] = knownHash
@ -49,7 +49,7 @@ type downloadTester struct {
func newTester(t *testing.T, hashes []common.Hash, blocks map[common.Hash]*types.Block) *downloadTester {
tester := &downloadTester{t: t, hashes: hashes, blocks: blocks, done: make(chan bool)}
downloader := New(tester.hasBlock, tester.insertChain)
downloader := New(tester.hasBlock, tester.insertChain, func() *big.Int { return new(big.Int) })
tester.downloader = downloader
return tester
@ -84,7 +84,7 @@ func (dl *downloadTester) getBlocks(id string) func([]common.Hash) error {
blocks[i] = dl.blocks[hash]
}
go dl.downloader.DeliverBlocks(id, blocks)
go dl.downloader.DeliverChunk(id, blocks)
return nil
}
@ -109,11 +109,11 @@ func TestDownload(t *testing.T) {
glog.SetV(logger.Detail)
glog.SetToStderr(true)
hashes := createHashes(1000)
hashes := createHashes(0, 1000)
blocks := createBlocksFromHashes(hashes)
tester := newTester(t, hashes, blocks)
tester.newPeer("peer1", big.NewInt(10000), hashes[len(hashes)-1])
tester.newPeer("peer1", big.NewInt(10000), hashes[0])
tester.newPeer("peer2", big.NewInt(0), common.Hash{})
tester.badBlocksPeer("peer3", big.NewInt(0), common.Hash{})
tester.badBlocksPeer("peer4", big.NewInt(0), common.Hash{})
@ -126,3 +126,30 @@ success:
t.Error("timout")
}
}
func TestMissing(t *testing.T) {
t.Skip()
glog.SetV(logger.Detail)
glog.SetToStderr(true)
hashes := createHashes(0, 1000)
extraHashes := createHashes(1001, 1003)
blocks := createBlocksFromHashes(append(extraHashes, hashes...))
tester := newTester(t, hashes, blocks)
tester.newPeer("peer1", big.NewInt(10000), hashes[len(hashes)-1])
hashes = append(extraHashes, hashes[:len(hashes)-1]...)
tester.newPeer("peer2", big.NewInt(0), common.Hash{})
success1:
select {
case <-tester.done:
break success1
case <-time.After(10 * time.Second): // XXX this could actually fail on a slow computer
t.Error("timout")
}
tester.downloader.AddBlock("peer2", blocks[hashes[len(hashes)-1]], big.NewInt(10001))
}

44
eth/downloader/peer.go
View File

@ -13,9 +13,51 @@ const (
idleState = 4
)
type hashFetcherFn func(common.Hash) error
type blockFetcherFn func([]common.Hash) error
// XXX make threadsafe!!!!
type peers map[string]*peer
func (p peers) get(state int) []*peer {
var peers []*peer
for _, peer := range p {
peer.mu.RLock()
if peer.state == state {
peers = append(peers, peer)
}
peer.mu.RUnlock()
}
return peers
}
func (p peers) setState(id string, state int) {
if peer, exist := p[id]; exist {
peer.mu.Lock()
defer peer.mu.Unlock()
peer.state = state
}
}
func (p peers) getPeer(id string) *peer {
return p[id]
}
func (p peers) bestPeer() *peer {
var peer *peer
for _, cp := range p {
if peer == nil || cp.td.Cmp(peer.td) > 0 {
peer = cp
}
}
return peer
}
// peer represents an active peer
type peer struct {
state int
state int // Peer state (working, idle)
rep int // TODO peer reputation
mu sync.RWMutex
id string

44
eth/downloader/queue.go
View File

@ -2,16 +2,20 @@ package downloader
import (
"math"
"math/big"
"sync"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core/types"
"gopkg.in/fatih/set.v0"
)
// queue represents hashes that are either need fetching or are being fetched
type queue struct {
hashPool *set.Set
hashPool *set.Set
fetchPool *set.Set
blockHashes *set.Set
mu sync.Mutex
fetching map[string]*chunk
@ -20,8 +24,10 @@ type queue struct {
func newqueue() *queue {
return &queue{
hashPool: set.New(),
fetching: make(map[string]*chunk),
hashPool: set.New(),
fetchPool: set.New(),
blockHashes: set.New(),
fetching: make(map[string]*chunk),
}
}
@ -50,6 +56,8 @@ func (c *queue) get(p *peer, max int) *chunk {
})
// remove the fetchable hashes from hash pool
c.hashPool.Separate(hashes)
c.fetchPool.Merge(hashes)
// Create a new chunk for the seperated hashes. The time is being used
// to reset the chunk (timeout)
chunk := &chunk{hashes, time.Now()}
@ -60,6 +68,22 @@ func (c *queue) get(p *peer, max int) *chunk {
return chunk
}
func (c *queue) has(hash common.Hash) bool {
return c.hashPool.Has(hash) || c.fetchPool.Has(hash)
}
func (c *queue) addBlock(id string, block *types.Block, td *big.Int) {
c.mu.Lock()
defer c.mu.Unlock()
// when adding a block make sure it doesn't already exist
if !c.blockHashes.Has(block.Hash()) {
c.hashPool.Remove(block.Hash())
c.blocks = append(c.blocks, block)
}
}
// deliver delivers a chunk to the queue that was requested of the peer
func (c *queue) deliver(id string, blocks []*types.Block) {
c.mu.Lock()
defer c.mu.Unlock()
@ -70,15 +94,19 @@ func (c *queue) deliver(id string, blocks []*types.Block) {
delete(c.fetching, id)
// seperate the blocks and the hashes
chunk.seperate(blocks)
blockHashes := chunk.fetchedHashes(blocks)
// merge block hashes
c.blockHashes.Merge(blockHashes)
// Add the blocks
c.blocks = append(c.blocks, blocks...)
// Add back whatever couldn't be delivered
c.hashPool.Merge(chunk.hashes)
c.fetchPool.Separate(chunk.hashes)
}
}
// puts puts sets of hashes on to the queue for fetching
func (c *queue) put(hashes *set.Set) {
c.mu.Lock()
defer c.mu.Unlock()
@ -91,8 +119,12 @@ type chunk struct {
itime time.Time
}
func (ch *chunk) seperate(blocks []*types.Block) {
func (ch *chunk) fetchedHashes(blocks []*types.Block) *set.Set {
fhashes := set.New()
for _, block := range blocks {
ch.hashes.Remove(block.Hash())
fhashes.Add(block.Hash())
}
ch.hashes.Separate(fhashes)
return fhashes
}