From c4f224932f69099f595211755ebc0a9933616315 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?P=C3=A9ter=20Szil=C3=A1gyi?= Date: Mon, 8 Jun 2015 14:46:31 +0300 Subject: eth/downloader: reject peer registration if head is banned --- eth/downloader/downloader.go | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-) (limited to 'eth') diff --git a/eth/downloader/downloader.go b/eth/downloader/downloader.go index 7eda49186..92cb1a650 100644 --- a/eth/downloader/downloader.go +++ b/eth/downloader/downloader.go @@ -36,6 +36,7 @@ var ( errUnknownPeer = errors.New("peer is unknown or unhealthy") ErrBadPeer = errors.New("action from bad peer ignored") ErrStallingPeer = errors.New("peer is stalling") + errBannedHead = errors.New("peer head hash already banned") errNoPeers = errors.New("no peers to keep download active") ErrPendingQueue = errors.New("pending items in queue") ErrTimeout = errors.New("timeout") @@ -72,11 +73,10 @@ type crossCheck struct { type Downloader struct { mux *event.TypeMux - mu sync.RWMutex queue *queue // Scheduler for selecting the hashes to download peers *peerSet // Set of active peers from which download can proceed checks map[common.Hash]*crossCheck // Pending cross checks to verify a hash chain - banned *set.SetNonTS // Set of hashes we've received and banned + banned *set.Set // Set of hashes we've received and banned // Callbacks hasBlock hashCheckFn @@ -114,7 +114,7 @@ func New(mux *event.TypeMux, hasBlock hashCheckFn, getBlock getBlockFn) *Downloa blockCh: make(chan blockPack, 1), } // Inject all the known bad hashes - downloader.banned = set.NewNonTS() + downloader.banned = set.New() for hash, _ := range core.BadHashes { downloader.banned.Add(hash) } @@ -133,6 +133,12 @@ func (d *Downloader) Synchronising() bool { // 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 { + // If the peer wants to send a banned hash, reject + if d.banned.Has(head) { + glog.V(logger.Debug).Infoln("Register rejected, head hash banned:", id) + return errBannedHead + } + // Otherwise try to construct and register the peer 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) @@ -199,6 +205,8 @@ func (d *Downloader) TakeBlocks() []*Block { return d.queue.TakeBlocks() } +// Has checks if the downloader knows about a particular hash, meaning that its +// either already downloaded of pending retrieval. func (d *Downloader) Has(hash common.Hash) bool { return d.queue.Has(hash) } @@ -604,14 +612,17 @@ func (d *Downloader) banBlocks(peerId string, head common.Hash) error { // Ban the head hash and phase out any excess d.banned.Add(blocks[index].Hash()) for d.banned.Size() > maxBannedHashes { + var evacuate common.Hash + d.banned.Each(func(item interface{}) bool { // Skip any hard coded bans if core.BadHashes[item.(common.Hash)] { return true } - d.banned.Remove(item) + evacuate = item.(common.Hash) return false }) + d.banned.Remove(evacuate) } glog.V(logger.Debug).Infof("Banned %d blocks from: %s", index+1, peerId) return nil -- cgit v1.2.3