plugeth/eth/sync.go

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package eth
import (
"math"
"sync/atomic"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/eth/downloader"
"github.com/ethereum/go-ethereum/logger"
"github.com/ethereum/go-ethereum/logger/glog"
)
const (
forceSyncCycle = 10 * time.Second // Time interval to force syncs, even if few peers are available
blockProcCycle = 500 * time.Millisecond // Time interval to check for new blocks to process
notifyCheckCycle = 100 * time.Millisecond // Time interval to allow hash notifies to fulfill before hard fetching
notifyArriveTimeout = 500 * time.Millisecond // Time allowance before an announced block is explicitly requested
notifyFetchTimeout = 5 * time.Second // Maximum alloted time to return an explicitly requested block
minDesiredPeerCount = 5 // Amount of peers desired to start syncing
blockProcAmount = 256
)
// blockAnnounce is the hash notification of the availability of a new block in
// the network.
type blockAnnounce struct {
hash common.Hash
peer *peer
time time.Time
}
// fetcher is responsible for collecting hash notifications, and periodically
// checking all unknown ones and individually fetching them.
func (pm *ProtocolManager) fetcher() {
announces := make(map[common.Hash]*blockAnnounce)
request := make(map[*peer][]common.Hash)
pending := make(map[common.Hash]*blockAnnounce)
cycle := time.Tick(notifyCheckCycle)
// Iterate the block fetching until a quit is requested
for {
select {
case notifications := <-pm.newHashCh:
// A batch of hashes the notified, schedule them for retrieval
glog.V(logger.Debug).Infof("Scheduling %d hash announcements from %s", len(notifications), notifications[0].peer.id)
for _, announce := range notifications {
announces[announce.hash] = announce
}
case <-cycle:
// Clean up any expired block fetches
for hash, announce := range pending {
if time.Since(announce.time) > notifyFetchTimeout {
delete(pending, hash)
}
}
// Check if any notified blocks failed to arrive
for hash, announce := range announces {
if time.Since(announce.time) > notifyArriveTimeout {
if !pm.chainman.HasBlock(hash) {
request[announce.peer] = append(request[announce.peer], hash)
pending[hash] = announce
}
delete(announces, hash)
}
}
if len(request) == 0 {
break
}
// Send out all block requests
for peer, hashes := range request {
glog.V(logger.Debug).Infof("Explicitly fetching %d blocks from %s", len(hashes), peer.id)
peer.requestBlocks(hashes)
}
request = make(map[*peer][]common.Hash)
case filter := <-pm.newBlockCh:
// Blocks arrived, extract any explicit fetches, return all else
var blocks types.Blocks
select {
case blocks = <-filter:
case <-pm.quitSync:
return
}
explicit, download := []*types.Block{}, []*types.Block{}
for _, block := range blocks {
hash := block.Hash()
// Filter explicitly requested blocks from hash announcements
if _, ok := pending[hash]; ok {
// Discard if already imported by other means
if !pm.chainman.HasBlock(hash) {
explicit = append(explicit, block)
} else {
delete(pending, hash)
}
} else {
download = append(download, block)
}
}
select {
case filter <- download:
case <-pm.quitSync:
return
}
// If any explicit fetches were replied to, import them
if count := len(explicit); count > 0 {
glog.V(logger.Debug).Infof("Importing %d explicitly fetched blocks", count)
go func() {
for _, block := range explicit {
hash := block.Hash()
// Make sure there's still something pending to import
if announce := pending[hash]; announce != nil {
delete(pending, hash)
if err := pm.importBlock(announce.peer, block, nil); err != nil {
glog.V(logger.Detail).Infof("Failed to import explicitly fetched block: %v", err)
return
}
}
}
}()
}
case <-pm.quitSync:
return
}
}
}
// syncer is responsible for periodically synchronising with the network, both
// downloading hashes and blocks as well as retrieving cached ones.
func (pm *ProtocolManager) syncer() {
forceSync := time.Tick(forceSyncCycle)
blockProc := time.Tick(blockProcCycle)
blockProcPend := int32(0)
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for {
select {
case <-pm.newPeerCh:
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// Make sure we have peers to select from, then sync
if pm.peers.Len() < minDesiredPeerCount {
break
}
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go pm.synchronise(pm.peers.BestPeer())
case <-forceSync:
// Force a sync even if not enough peers are present
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go pm.synchronise(pm.peers.BestPeer())
case <-blockProc:
// Try to pull some blocks from the downloaded
if atomic.CompareAndSwapInt32(&blockProcPend, 0, 1) {
go func() {
pm.processBlocks()
atomic.StoreInt32(&blockProcPend, 0)
}()
}
case <-pm.quitSync:
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return
}
}
}
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// processBlocks retrieves downloaded blocks from the download cache and tries
// to construct the local block chain with it. Note, since the block retrieval
// order matters, access to this function *must* be synchronized/serialized.
func (pm *ProtocolManager) processBlocks() error {
pm.wg.Add(1)
defer pm.wg.Done()
// Short circuit if no blocks are available for insertion
blocks := pm.downloader.TakeBlocks()
if len(blocks) == 0 {
return nil
}
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 && !pm.quit {
// Retrieve the first batch of blocks to insert
max := int(math.Min(float64(len(blocks)), float64(blockProcAmount)))
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 := pm.chainman.InsertChain(raw)
if err != nil {
glog.V(logger.Debug).Infoln("Downloaded block import failed:", err)
pm.removePeer(blocks[index].OriginPeer)
pm.downloader.Cancel()
return err
}
blocks = blocks[max:]
}
return nil
}
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// 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 (pm *ProtocolManager) synchronise(peer *peer) {
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// Short circuit if no peers are available
if peer == nil {
return
}
// Make sure the peer's TD is higher than our own. If not drop.
if peer.td.Cmp(pm.chainman.Td()) <= 0 {
return
}
// FIXME if we have the hash in our chain and the TD of the peer is
// much higher than ours, something is wrong with us or the peer.
// Check if the hash is on our own chain
if pm.chainman.HasBlock(peer.recentHash) {
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glog.V(logger.Debug).Infoln("Synchronisation canceled: head already known")
return
}
// Get the hashes from the peer (synchronously)
glog.V(logger.Detail).Infof("Attempting synchronisation: %v, 0x%x", peer.id, peer.recentHash)
err := pm.downloader.Synchronise(peer.id, peer.recentHash)
switch err {
case nil:
glog.V(logger.Detail).Infof("Synchronisation completed")
case downloader.ErrBusy:
glog.V(logger.Detail).Infof("Synchronisation already in progress")
case downloader.ErrTimeout, downloader.ErrBadPeer, downloader.ErrEmptyHashSet, downloader.ErrInvalidChain, downloader.ErrCrossCheckFailed:
glog.V(logger.Debug).Infof("Removing peer %v: %v", peer.id, err)
pm.removePeer(peer.id)
case downloader.ErrPendingQueue:
glog.V(logger.Debug).Infoln("Synchronisation aborted:", err)
default:
glog.V(logger.Warn).Infof("Synchronisation failed: %v", err)
}
}