eth, eth/downloader, eth/fetcher: delete eth/61 code

The eth/61 protocol was disabled in #2776, this commit removes its
message handlers and hash-chain sync logic.

6 files changed, 75 insertions, 932 deletions

diff --git a/eth/downloader/downloader.go b/eth/downloader/downloader.go
index 01c0818a0..1e9bc27bc 100644
--- a/eth/downloader/downloader.go
+++ b/eth/downloader/downloader.go
@@ -48,23 +48,17 @@ var (
 	MaxReceiptFetch = 256 // Amount of transaction receipts to allow fetching per request
 	MaxStateFetch   = 384 // Amount of node state values to allow fetching per request
 
-	MaxForkAncestry = 3 * params.EpochDuration.Uint64() // Maximum chain reorganisation
-
-	hashTTL        = 3 * time.Second     // [eth/61] Time it takes for a hash request to time out
-	blockTargetRTT = 3 * time.Second / 2 // [eth/61] Target time for completing a block retrieval request
-	blockTTL       = 3 * blockTargetRTT  // [eth/61] Maximum time allowance before a block request is considered expired
-
-	rttMinEstimate   = 2 * time.Second  // Minimum round-trip time to target for download requests
-	rttMaxEstimate   = 20 * time.Second // Maximum rount-trip time to target for download requests
-	rttMinConfidence = 0.1              // Worse confidence factor in our estimated RTT value
-	ttlScaling       = 3                // Constant scaling factor for RTT -> TTL conversion
-	ttlLimit         = time.Minute      // Maximum TTL allowance to prevent reaching crazy timeouts
+	MaxForkAncestry  = 3 * params.EpochDuration.Uint64() // Maximum chain reorganisation
+	rttMinEstimate   = 2 * time.Second                   // Minimum round-trip time to target for download requests
+	rttMaxEstimate   = 20 * time.Second                  // Maximum rount-trip time to target for download requests
+	rttMinConfidence = 0.1                               // Worse confidence factor in our estimated RTT value
+	ttlScaling       = 3                                 // Constant scaling factor for RTT -> TTL conversion
+	ttlLimit         = time.Minute                       // Maximum TTL allowance to prevent reaching crazy timeouts
 
 	qosTuningPeers   = 5    // Number of peers to tune based on (best peers)
 	qosConfidenceCap = 10   // Number of peers above which not to modify RTT confidence
 	qosTuningImpact  = 0.25 // Impact that a new tuning target has on the previous value
 
-	maxQueuedHashes   = 32 * 1024 // [eth/61] Maximum number of hashes to queue for import (DOS protection)
 	maxQueuedHeaders  = 32 * 1024 // [eth/62] Maximum number of headers to queue for import (DOS protection)
 	maxHeadersProcess = 2048      // Number of header download results to import at once into the chain
 	maxResultsProcess = 2048      // Number of content download results to import at once into the chain
@@ -84,16 +78,13 @@ var (
 	errStallingPeer            = errors.New("peer is stalling")
 	errNoPeers                 = errors.New("no peers to keep download active")
 	errTimeout                 = errors.New("timeout")
-	errEmptyHashSet            = errors.New("empty hash set by peer")
 	errEmptyHeaderSet          = errors.New("empty header set by peer")
 	errPeersUnavailable        = errors.New("no peers available or all tried for download")
-	errAlreadyInPool           = errors.New("hash already in pool")
 	errInvalidAncestor         = errors.New("retrieved ancestor is invalid")
 	errInvalidChain            = errors.New("retrieved hash chain is invalid")
 	errInvalidBlock            = errors.New("retrieved block is invalid")
 	errInvalidBody             = errors.New("retrieved block body is invalid")
 	errInvalidReceipt          = errors.New("retrieved receipt is invalid")
-	errCancelHashFetch         = errors.New("hash download canceled (requested)")
 	errCancelBlockFetch        = errors.New("block download canceled (requested)")
 	errCancelHeaderFetch       = errors.New("block header download canceled (requested)")
 	errCancelBodyFetch         = errors.New("block body download canceled (requested)")
@@ -102,6 +93,7 @@ var (
 	errCancelHeaderProcessing  = errors.New("header processing canceled (requested)")
 	errCancelContentProcessing = errors.New("content processing canceled (requested)")
 	errNoSyncActive            = errors.New("no sync active")
+	errTooOld                  = errors.New("peer doesn't speak recent enough protocol version (need version >= 62)")
 )
 
 type Downloader struct {
@@ -146,13 +138,10 @@ type Downloader struct {
 
 	// Channels
 	newPeerCh     chan *peer
-	hashCh        chan dataPack        // [eth/61] Channel receiving inbound hashes
-	blockCh       chan dataPack        // [eth/61] Channel receiving inbound blocks
 	headerCh      chan dataPack        // [eth/62] Channel receiving inbound block headers
 	bodyCh        chan dataPack        // [eth/62] Channel receiving inbound block bodies
 	receiptCh     chan dataPack        // [eth/63] Channel receiving inbound receipts
 	stateCh       chan dataPack        // [eth/63] Channel receiving inbound node state data
-	blockWakeCh   chan bool            // [eth/61] Channel to signal the block fetcher of new tasks
 	bodyWakeCh    chan bool            // [eth/62] Channel to signal the block body fetcher of new tasks
 	receiptWakeCh chan bool            // [eth/63] Channel to signal the receipt fetcher of new tasks
 	stateWakeCh   chan bool            // [eth/63] Channel to signal the state fetcher of new tasks
@@ -199,13 +188,10 @@ func New(stateDb ethdb.Database, mux *event.TypeMux, hasHeader headerCheckFn, ha
 		rollback:         rollback,
 		dropPeer:         dropPeer,
 		newPeerCh:        make(chan *peer, 1),
-		hashCh:           make(chan dataPack, 1),
-		blockCh:          make(chan dataPack, 1),
 		headerCh:         make(chan dataPack, 1),
 		bodyCh:           make(chan dataPack, 1),
 		receiptCh:        make(chan dataPack, 1),
 		stateCh:          make(chan dataPack, 1),
-		blockWakeCh:      make(chan bool, 1),
 		bodyWakeCh:       make(chan bool, 1),
 		receiptWakeCh:    make(chan bool, 1),
 		stateWakeCh:      make(chan bool, 1),
@@ -251,12 +237,11 @@ 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, version int, head common.Hash,
-	getRelHashes relativeHashFetcherFn, getAbsHashes absoluteHashFetcherFn, getBlocks blockFetcherFn, // eth/61 callbacks, remove when upgrading
 	getRelHeaders relativeHeaderFetcherFn, getAbsHeaders absoluteHeaderFetcherFn, getBlockBodies blockBodyFetcherFn,
 	getReceipts receiptFetcherFn, getNodeData stateFetcherFn) error {
 
 	glog.V(logger.Detail).Infoln("Registering peer", id)
-	if err := d.peers.Register(newPeer(id, version, head, getRelHashes, getAbsHashes, getBlocks, getRelHeaders, getAbsHeaders, getBlockBodies, getReceipts, getNodeData)); err != nil {
+	if err := d.peers.Register(newPeer(id, version, head, getRelHeaders, getAbsHeaders, getBlockBodies, getReceipts, getNodeData)); err != nil {
 		glog.V(logger.Error).Infoln("Register failed:", err)
 		return err
 	}
@@ -291,7 +276,9 @@ func (d *Downloader) Synchronise(id string, head common.Hash, td *big.Int, mode
 	case errBusy:
 		glog.V(logger.Detail).Infof("Synchronisation already in progress")
 
-	case errTimeout, errBadPeer, errStallingPeer, errEmptyHashSet, errEmptyHeaderSet, errPeersUnavailable, errInvalidAncestor, errInvalidChain:
+	case errTimeout, errBadPeer, errStallingPeer,
+		errEmptyHeaderSet, errPeersUnavailable, errTooOld,
+		errInvalidAncestor, errInvalidChain:
 		glog.V(logger.Debug).Infof("Removing peer %v: %v", id, err)
 		d.dropPeer(id)
 
@@ -323,13 +310,13 @@ func (d *Downloader) synchronise(id string, hash common.Hash, td *big.Int, mode
 	d.queue.Reset()
 	d.peers.Reset()
 
-	for _, ch := range []chan bool{d.blockWakeCh, d.bodyWakeCh, d.receiptWakeCh, d.stateWakeCh} {
+	for _, ch := range []chan bool{d.bodyWakeCh, d.receiptWakeCh, d.stateWakeCh} {
 		select {
 		case <-ch:
 		default:
 		}
 	}
-	for _, ch := range []chan dataPack{d.hashCh, d.blockCh, d.headerCh, d.bodyCh, d.receiptCh, d.stateCh} {
+	for _, ch := range []chan dataPack{d.headerCh, d.bodyCh, d.receiptCh, d.stateCh} {
 		for empty := false; !empty; {
 			select {
 			case <-ch:
@@ -377,105 +364,73 @@ func (d *Downloader) syncWithPeer(p *peer, hash common.Hash, td *big.Int) (err e
 			d.mux.Post(DoneEvent{})
 		}
 	}()
+	if p.version < 62 {
+		return errTooOld
+	}
 
 	glog.V(logger.Debug).Infof("Synchronising with the network using: %s [eth/%d]", p.id, p.version)
 	defer func(start time.Time) {
 		glog.V(logger.Debug).Infof("Synchronisation terminated after %v", time.Since(start))
 	}(time.Now())
 
-	switch {
-	case p.version == 61:
-		// Look up the sync boundaries: the common ancestor and the target block
-		latest, err := d.fetchHeight61(p)
-		if err != nil {
-			return err
-		}
-		origin, err := d.findAncestor61(p, latest)
-		if err != nil {
-			return err
-		}
-		d.syncStatsLock.Lock()
-		if d.syncStatsChainHeight <= origin || d.syncStatsChainOrigin > origin {
-			d.syncStatsChainOrigin = origin
-		}
-		d.syncStatsChainHeight = latest
-		d.syncStatsLock.Unlock()
+	// Look up the sync boundaries: the common ancestor and the target block
+	latest, err := d.fetchHeight(p)
+	if err != nil {
+		return err
+	}
+	height := latest.Number.Uint64()
 
-		// Initiate the sync using a concurrent hash and block retrieval algorithm
-		d.queue.Prepare(origin+1, d.mode, 0, nil)
-		if d.syncInitHook != nil {
-			d.syncInitHook(origin, latest)
-		}
-		return d.spawnSync(origin+1,
-			func() error { return d.fetchHashes61(p, td, origin+1) },
-			func() error { return d.fetchBlocks61(origin + 1) },
-		)
-
-	case p.version >= 62:
-		// Look up the sync boundaries: the common ancestor and the target block
-		latest, err := d.fetchHeight(p)
-		if err != nil {
-			return err
-		}
-		height := latest.Number.Uint64()
+	origin, err := d.findAncestor(p, height)
+	if err != nil {
+		return err
+	}
+	d.syncStatsLock.Lock()
+	if d.syncStatsChainHeight <= origin || d.syncStatsChainOrigin > origin {
+		d.syncStatsChainOrigin = origin
+	}
+	d.syncStatsChainHeight = height
+	d.syncStatsLock.Unlock()
 
-		origin, err := d.findAncestor(p, height)
-		if err != nil {
-			return err
-		}
-		d.syncStatsLock.Lock()
-		if d.syncStatsChainHeight <= origin || d.syncStatsChainOrigin > origin {
-			d.syncStatsChainOrigin = origin
-		}
-		d.syncStatsChainHeight = height
-		d.syncStatsLock.Unlock()
-
-		// Initiate the sync using a concurrent header and content retrieval algorithm
-		pivot := uint64(0)
-		switch d.mode {
-		case LightSync:
-			pivot = height
-		case FastSync:
-			// Calculate the new fast/slow sync pivot point
-			if d.fsPivotLock == nil {
-				pivotOffset, err := rand.Int(rand.Reader, big.NewInt(int64(fsPivotInterval)))
-				if err != nil {
-					panic(fmt.Sprintf("Failed to access crypto random source: %v", err))
-				}
-				if height > uint64(fsMinFullBlocks)+pivotOffset.Uint64() {
-					pivot = height - uint64(fsMinFullBlocks) - pivotOffset.Uint64()
-				}
-			} else {
-				// Pivot point locked in, use this and do not pick a new one!
-				pivot = d.fsPivotLock.Number.Uint64()
+	// Initiate the sync using a concurrent header and content retrieval algorithm
+	pivot := uint64(0)
+	switch d.mode {
+	case LightSync:
+		pivot = height
+	case FastSync:
+		// Calculate the new fast/slow sync pivot point
+		if d.fsPivotLock == nil {
+			pivotOffset, err := rand.Int(rand.Reader, big.NewInt(int64(fsPivotInterval)))
+			if err != nil {
+				panic(fmt.Sprintf("Failed to access crypto random source: %v", err))
 			}
-			// If the point is below the origin, move origin back to ensure state download
-			if pivot < origin {
-				if pivot > 0 {
-					origin = pivot - 1
-				} else {
-					origin = 0
-				}
+			if height > uint64(fsMinFullBlocks)+pivotOffset.Uint64() {
+				pivot = height - uint64(fsMinFullBlocks) - pivotOffset.Uint64()
 			}
-			glog.V(logger.Debug).Infof("Fast syncing until pivot block #%d", pivot)
+		} else {
+			// Pivot point locked in, use this and do not pick a new one!
+			pivot = d.fsPivotLock.Number.Uint64()
 		}
-		d.queue.Prepare(origin+1, d.mode, pivot, latest)
-		if d.syncInitHook != nil {
-			d.syncInitHook(origin, height)
+		// If the point is below the origin, move origin back to ensure state download
+		if pivot < origin {
+			if pivot > 0 {
+				origin = pivot - 1
+			} else {
+				origin = 0
+			}
 		}
-		return d.spawnSync(origin+1,
-			func() error { return d.fetchHeaders(p, origin+1) },    // Headers are always retrieved
-			func() error { return d.processHeaders(origin+1, td) }, // Headers are always retrieved
-			func() error { return d.fetchBodies(origin + 1) },      // Bodies are retrieved during normal and fast sync
-			func() error { return d.fetchReceipts(origin + 1) },    // Receipts are retrieved during fast sync
-			func() error { return d.fetchNodeData() },              // Node state data is retrieved during fast sync
-		)
-
-	default:
-		// Something very wrong, stop right here
-		glog.V(logger.Error).Infof("Unsupported eth protocol: %d", p.version)
-		return errBadPeer
+		glog.V(logger.Debug).Infof("Fast syncing until pivot block #%d", pivot)
+	}
+	d.queue.Prepare(origin+1, d.mode, pivot, latest)
+	if d.syncInitHook != nil {
+		d.syncInitHook(origin, height)
 	}
+	return d.spawnSync(origin+1,
+		func() error { return d.fetchHeaders(p, origin+1) },    // Headers are always retrieved
+		func() error { return d.processHeaders(origin+1, td) }, // Headers are always retrieved
+		func() error { return d.fetchBodies(origin + 1) },      // Bodies are retrieved during normal and fast sync
+		func() error { return d.fetchReceipts(origin + 1) },    // Receipts are retrieved during fast sync
+		func() error { return d.fetchNodeData() },              // Node state data is retrieved during fast sync
+	)
 }
 
 // spawnSync runs d.process and all given fetcher functions to completion in
@@ -540,452 +495,6 @@ func (d *Downloader) Terminate() {
 	d.cancel()
 }
 
-// fetchHeight61 retrieves the head block of the remote peer to aid in estimating
-// the total time a pending synchronisation would take.
-func (d *Downloader) fetchHeight61(p *peer) (uint64, error) {
-	glog.V(logger.Debug).Infof("%v: retrieving remote chain height", p)
-
-	// Request the advertised remote head block and wait for the response
-	go p.getBlocks([]common.Hash{p.head})
-
-	timeout := time.After(hashTTL)
-	for {
-		select {
-		case <-d.cancelCh:
-			return 0, errCancelBlockFetch
-
-		case packet := <-d.blockCh:
-			// Discard anything not from the origin peer
-			if packet.PeerId() != p.id {
-				glog.V(logger.Debug).Infof("Received blocks from incorrect peer(%s)", packet.PeerId())
-				break
-			}
-			// Make sure the peer actually gave something valid
-			blocks := packet.(*blockPack).blocks
-			if len(blocks) != 1 {
-				glog.V(logger.Debug).Infof("%v: invalid number of head blocks: %d != 1", p, len(blocks))
-				return 0, errBadPeer
-			}
-			return blocks[0].NumberU64(), nil
-
-		case <-timeout:
-			glog.V(logger.Debug).Infof("%v: head block timeout", p)
-			return 0, errTimeout
-
-		case <-d.hashCh:
-			// Out of bounds hashes received, ignore them
-
-		case <-d.headerCh:
-		case <-d.bodyCh:
-		case <-d.stateCh:
-		case <-d.receiptCh:
-			// Ignore eth/{62,63} packets because this is eth/61.
-			// These can arrive as a late delivery from a previous sync.
-		}
-	}
-}
-
-// findAncestor61 tries to locate the common ancestor block of the local chain and
-// a remote peers blockchain. In the general case when our node was in sync and
-// on the correct chain, checking the top N blocks should already get us a match.
-// In the rare scenario when we ended up on a long reorganisation (i.e. none of
-// the head blocks match), we do a binary search to find the common ancestor.
-func (d *Downloader) findAncestor61(p *peer, height uint64) (uint64, error) {
-	glog.V(logger.Debug).Infof("%v: looking for common ancestor", p)
-
-	// Figure out the valid ancestor range to prevent rewrite attacks
-	floor, ceil := int64(-1), d.headBlock().NumberU64()
-	if ceil >= MaxForkAncestry {
-		floor = int64(ceil - MaxForkAncestry)
-	}
-	// Request the topmost blocks to short circuit binary ancestor lookup
-	head := ceil
-	if head > height {
-		head = height
-	}
-	from := int64(head) - int64(MaxHashFetch) + 1
-	if from < 0 {
-		from = 0
-	}
-	go p.getAbsHashes(uint64(from), MaxHashFetch)
-
-	// Wait for the remote response to the head fetch
-	number, hash := uint64(0), common.Hash{}
-	timeout := time.After(hashTTL)
-
-	for finished := false; !finished; {
-		select {
-		case <-d.cancelCh:
-			return 0, errCancelHashFetch
-
-		case packet := <-d.hashCh:
-			// Discard anything not from the origin peer
-			if packet.PeerId() != p.id {
-				glog.V(logger.Debug).Infof("Received hashes from incorrect peer(%s)", packet.PeerId())
-				break
-			}
-			// Make sure the peer actually gave something valid
-			hashes := packet.(*hashPack).hashes
-			if len(hashes) == 0 {
-				glog.V(logger.Debug).Infof("%v: empty head hash set", p)
-				return 0, errEmptyHashSet
-			}
-			// Check if a common ancestor was found
-			finished = true
-			for i := len(hashes) - 1; i >= 0; i-- {
-				// Skip any headers that underflow/overflow our requested set
-				header := d.getHeader(hashes[i])
-				if header == nil || header.Number.Int64() < from || header.Number.Uint64() > head {
-					continue
-				}
-				// Otherwise check if we already know the header or not
-				if d.hasBlockAndState(hashes[i]) {
-					number, hash = header.Number.Uint64(), header.Hash()
-					break
-				}
-			}
-
-		case <-timeout:
-			glog.V(logger.Debug).Infof("%v: head hash timeout", p)
-			return 0, errTimeout
-
-		case <-d.blockCh:
-			// Out of bounds blocks received, ignore them
-
-		case <-d.headerCh:
-		case <-d.bodyCh:
-		case <-d.stateCh:
-		case <-d.receiptCh:
-			// Ignore eth/{62,63} packets because this is eth/61.
-			// These can arrive as a late delivery from a previous sync.
-		}
-	}
-	// If the head fetch already found an ancestor, return
-	if !common.EmptyHash(hash) {
-		if int64(number) <= floor {
-			glog.V(logger.Warn).Infof("%v: potential rewrite attack: #%d [%x…] <= #%d limit", p, number, hash[:4], floor)
-			return 0, errInvalidAncestor
-		}
-		glog.V(logger.Debug).Infof("%v: common ancestor: #%d [%x…]", p, number, hash[:4])
-		return number, nil
-	}
-	// Ancestor not found, we need to binary search over our chain
-	start, end := uint64(0), head
-	if floor > 0 {
-		start = uint64(floor)
-	}
-	for start+1 < end {
-		// Split our chain interval in two, and request the hash to cross check
-		check := (start + end) / 2
-
-		timeout := time.After(hashTTL)
-		go p.getAbsHashes(uint64(check), 1)
-
-		// Wait until a reply arrives to this request
-		for arrived := false; !arrived; {
-			select {
-			case <-d.cancelCh:
-				return 0, errCancelHashFetch
-
-			case packet := <-d.hashCh:
-				// Discard anything not from the origin peer
-				if packet.PeerId() != p.id {
-					glog.V(logger.Debug).Infof("Received hashes from incorrect peer(%s)", packet.PeerId())
-					break
-				}
-				// Make sure the peer actually gave something valid
-				hashes := packet.(*hashPack).hashes
-				if len(hashes) != 1 {
-					glog.V(logger.Debug).Infof("%v: invalid search hash set (%d)", p, len(hashes))
-					return 0, errBadPeer
-				}
-				arrived = true
-
-				// Modify the search interval based on the response
-				if !d.hasBlockAndState(hashes[0]) {
-					end = check
-					break
-				}
-				block := d.getBlock(hashes[0]) // this doesn't check state, hence the above explicit check
-				if block.NumberU64() != check {
-					glog.V(logger.Debug).Infof("%v: non requested hash #%d [%x…], instead of #%d", p, block.NumberU64(), block.Hash().Bytes()[:4], check)
-					return 0, errBadPeer
-				}
-				start = check
-
-			case <-timeout:
-				glog.V(logger.Debug).Infof("%v: search hash timeout", p)
-				return 0, errTimeout
-
-			case <-d.blockCh:
-				// Out of bounds blocks received, ignore them
-
-			case <-d.headerCh:
-			case <-d.bodyCh:
-			case <-d.stateCh:
-			case <-d.receiptCh:
-				// Ignore eth/{62,63} packets because this is eth/61.
-				// These can arrive as a late delivery from a previous sync.
-			}
-		}
-	}
-	// Ensure valid ancestry and return
-	if int64(start) <= floor {
-		glog.V(logger.Warn).Infof("%v: potential rewrite attack: #%d [%x…] <= #%d limit", p, start, hash[:4], floor)
-		return 0, errInvalidAncestor
-	}
-	glog.V(logger.Debug).Infof("%v: common ancestor: #%d [%x…]", p, start, hash[:4])
-	return start, nil
-}
-
-// fetchHashes61 keeps retrieving hashes from the requested number, until no more
-// are returned, potentially throttling on the way.
-func (d *Downloader) fetchHashes61(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
-	request := time.Now()       // time of the last fetch request
-	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)
-
-		request = time.Now()
-		timeout.Reset(hashTTL)
-		go p.getAbsHashes(from, MaxHashFetch)
-	}
-	// Start pulling hashes, until all are exhausted
-	getHashes(from)
-	gotHashes := false
-
-	for {
-		select {
-		case <-d.cancelCh:
-			return errCancelHashFetch
-
-		case packet := <-d.hashCh:
-			// Make sure the active peer is giving us the hashes
-			if packet.PeerId() != p.id {
-				glog.V(logger.Debug).Infof("Received hashes from incorrect peer(%s)", packet.PeerId())
-				break
-			}
-			hashReqTimer.UpdateSince(request)
-			timeout.Stop()
-
-			// If no more hashes are inbound, notify the block fetcher and return
-			if packet.Items() == 0 {
-				glog.V(logger.Debug).Infof("%v: no available hashes", p)
-
-				select {
-				case d.blockWakeCh <- 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. fetcher):
-				//
-				// 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.getTd(d.headBlock().Hash())) > 0 {
-					return errStallingPeer
-				}
-				return nil
-			}
-			gotHashes = true
-			hashes := packet.(*hashPack).hashes
-
-			// Otherwise insert all the new hashes, aborting in case of junk
-			glog.V(logger.Detail).Infof("%v: scheduling %d hashes from #%d", p, len(hashes), from)
-
-			inserts := d.queue.Schedule61(hashes, true)
-			if len(inserts) != len(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
-			if d.queue.PendingBlocks() < maxQueuedHashes {
-				// We still have hashes to fetch, send continuation wake signal (potential)
-				select {
-				case d.blockWakeCh <- true:
-				default:
-				}
-			} else {
-				// Hash limit reached, send a termination wake signal (enforced)
-				select {
-				case d.blockWakeCh <- false:
-				case <-d.cancelCh:
-				}
-				return nil
-			}
-			// Queue not yet full, fetch the next batch
-			from += uint64(len(hashes))
-			getHashes(from)
-
-		case <-timeout.C:
-			glog.V(logger.Debug).Infof("%v: hash request timed out", p)
-			hashTimeoutMeter.Mark(1)
-			return errTimeout
-
-		case <-d.headerCh:
-		case <-d.bodyCh:
-		case <-d.stateCh:
-		case <-d.receiptCh:
-			// Ignore eth/{62,63} packets because this is eth/61.
-			// These can arrive as a late delivery from a previous sync.
-		}
-	}
-}
-
-// fetchBlocks61 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) fetchBlocks61(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)
-
-	// Fetch blocks until the hash fetcher's done
-	finished := false
-	for {
-		select {
-		case <-d.cancelCh:
-			return errCancelBlockFetch
-
-		case packet := <-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(packet.PeerId()); peer != nil {
-				blocks := packet.(*blockPack).blocks
-
-				// Deliver the received chunk of blocks and check chain validity
-				accepted, err := d.queue.DeliverBlocks(peer.id, blocks)
-				if err == errInvalidChain {
-					return err
-				}
-				// Unless a peer delivered something completely else than requested (usually
-				// caused by a timed out request which came through in the end), set it to
-				// idle. If the delivery's stale, the peer should have already been idled.
-				if err != errStaleDelivery {
-					peer.SetBlocksIdle(accepted)
-				}
-				// Issue a log to the user to see what's going on
-				switch {
-				case err == nil && len(blocks) == 0:
-					glog.V(logger.Detail).Infof("%s: no blocks delivered", peer)
-				case err == nil:
-					glog.V(logger.Detail).Infof("%s: delivered %d blocks", peer, len(blocks))
-				default:
-					glog.V(logger.Detail).Infof("%s: delivery failed: %v", peer, err)
-				}
-			}
-			// Blocks arrived, try to update the progress
-			select {
-			case update <- struct{}{}:
-			default:
-			}
-
-		case cont := <-d.blockWakeCh:
-			// 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, fails := range d.queue.ExpireBlocks(blockTTL) {
-				if peer := d.peers.Peer(pid); peer != nil {
-					if fails > 1 {
-						glog.V(logger.Detail).Infof("%s: block delivery timeout", peer)
-						peer.SetBlocksIdle(0)
-					} else {
-						glog.V(logger.Debug).Infof("%s: stalling block delivery, dropping", peer)
-						d.dropPeer(pid)
-					}
-				}
-			}
-			// If there's nothing more to fetch, wait or terminate
-			if d.queue.PendingBlocks() == 0 {
-				if !d.queue.InFlightBlocks() && finished {
-					glog.V(logger.Debug).Infof("Block fetching completed")
-					return nil
-				}
-				break
-			}
-			// Send a download request to all idle peers, until throttled
-			throttled := false
-			idles, total := d.peers.BlockIdlePeers()
-
-			for _, peer := range idles {
-				// Short circuit if throttling activated
-				if d.queue.ShouldThrottleBlocks() {
-					throttled = true
-					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.ReserveBlocks(peer, peer.BlockCapacity(blockTargetRTT))
-				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.Fetch61(request); err != nil {
-					// Although we could try and make an attempt to fix this, this error really
-					// means that we've double allocated a fetch task to a peer. If that is the
-					// case, the internal state of the downloader and the queue is very wrong so
-					// better hard crash and note the error instead of silently accumulating into
-					// a much bigger issue.
-					panic(fmt.Sprintf("%v: fetch assignment failed", peer))
-				}
-			}
-			// Make sure that we have peers available for fetching. If all peers have been tried
-			// and all failed throw an error
-			if !throttled && !d.queue.InFlightBlocks() && len(idles) == total {
-				return errPeersUnavailable
-			}
-
-		case <-d.headerCh:
-		case <-d.bodyCh:
-		case <-d.stateCh:
-		case <-d.receiptCh:
-			// Ignore eth/{62,63} packets because this is eth/61.
-			// These can arrive as a late delivery from a previous sync.
-		}
-	}
-}
-
 // fetchHeight retrieves the head header of the remote peer to aid in estimating
 // the total time a pending synchronisation would take.
 func (d *Downloader) fetchHeight(p *peer) (*types.Header, error) {
@@ -1022,11 +531,6 @@ func (d *Downloader) fetchHeight(p *peer) (*types.Header, error) {
 		case <-d.stateCh:
 		case <-d.receiptCh:
 			// Out of bounds delivery, ignore
-
-		case <-d.hashCh:
-		case <-d.blockCh:
-			// Ignore eth/61 packets because this is eth/62+.
-			// These can arrive as a late delivery from a previous sync.
 		}
 	}
 }
@@ -1067,7 +571,7 @@ func (d *Downloader) findAncestor(p *peer, height uint64) (uint64, error) {
 	for finished := false; !finished; {
 		select {
 		case <-d.cancelCh:
-			return 0, errCancelHashFetch
+			return 0, errCancelHeaderFetch
 
 		case packet := <-d.headerCh:
 			// Discard anything not from the origin peer
@@ -1114,11 +618,6 @@ func (d *Downloader) findAncestor(p *peer, height uint64) (uint64, error) {
 		case <-d.stateCh:
 		case <-d.receiptCh:
 			// Out of bounds delivery, ignore
-
-		case <-d.hashCh:
-		case <-d.blockCh:
-			// Ignore eth/61 packets because this is eth/62+.
-			// These can arrive as a late delivery from a previous sync.
 		}
 	}
 	// If the head fetch already found an ancestor, return
@@ -1146,7 +645,7 @@ func (d *Downloader) findAncestor(p *peer, height uint64) (uint64, error) {
 		for arrived := false; !arrived; {
 			select {
 			case <-d.cancelCh:
-				return 0, errCancelHashFetch
+				return 0, errCancelHeaderFetch
 
 			case packer := <-d.headerCh:
 				// Discard anything not from the origin peer
@@ -1182,11 +681,6 @@ func (d *Downloader) findAncestor(p *peer, height uint64) (uint64, error) {
 			case <-d.stateCh:
 			case <-d.receiptCh:
 				// Out of bounds delivery, ignore
-
-			case <-d.hashCh:
-			case <-d.blockCh:
-				// Ignore eth/61 packets because this is eth/62+.
-				// These can arrive as a late delivery from a previous sync.
 			}
 		}
 	}
@@ -1305,11 +799,6 @@ func (d *Downloader) fetchHeaders(p *peer, from uint64) error {
 			case <-d.cancelCh:
 			}
 			return errBadPeer
-
-		case <-d.hashCh:
-		case <-d.blockCh:
-			// Ignore eth/61 packets because this is eth/62+.
-			// These can arrive as a late delivery from a previous sync.
 		}
 	}
 }
@@ -1623,11 +1112,6 @@ func (d *Downloader) fetchParts(errCancel error, deliveryCh chan dataPack, deliv
 			if !progressed && !throttled && !running && len(idles) == total && pending() > 0 {
 				return errPeersUnavailable
 			}
-
-		case <-d.hashCh:
-		case <-d.blockCh:
-			// Ignore eth/61 packets because this is eth/62+.
-			// These can arrive as a late delivery from a previous sync.
 		}
 	}
 }
@@ -1867,19 +1351,6 @@ func (d *Downloader) processContent() error {
 	}
 }
 
-// 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) (err error) {
-	return d.deliver(id, d.hashCh, &hashPack{id, hashes}, hashInMeter, hashDropMeter)
-}
-
-// 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) (err error) {
-	return d.deliver(id, d.blockCh, &blockPack{id, blocks}, blockInMeter, blockDropMeter)
-}
-
 // DeliverHeaders injects a new batch of block headers received from a remote
 // node into the download schedule.
 func (d *Downloader) DeliverHeaders(id string, headers []*types.Header) (err error) {
diff --git a/eth/downloader/downloader_test.go b/eth/downloader/downloader_test.go
index fac6ef81c..4ca28091c 100644
--- a/eth/downloader/downloader_test.go
+++ b/eth/downloader/downloader_test.go
@@ -399,14 +399,12 @@ func (dl *downloadTester) newSlowPeer(id string, version int, hashes []common.Ha
 
 	var err error
 	switch version {
-	case 61:
-		err = dl.downloader.RegisterPeer(id, version, hashes[0], dl.peerGetRelHashesFn(id, delay), dl.peerGetAbsHashesFn(id, delay), dl.peerGetBlocksFn(id, delay), nil, nil, nil, nil, nil)
 	case 62:
-		err = dl.downloader.RegisterPeer(id, version, hashes[0], nil, nil, nil, dl.peerGetRelHeadersFn(id, delay), dl.peerGetAbsHeadersFn(id, delay), dl.peerGetBodiesFn(id, delay), nil, nil)
+		err = dl.downloader.RegisterPeer(id, version, hashes[0], dl.peerGetRelHeadersFn(id, delay), dl.peerGetAbsHeadersFn(id, delay), dl.peerGetBodiesFn(id, delay), nil, nil)
 	case 63:
-		err = dl.downloader.RegisterPeer(id, version, hashes[0], nil, nil, nil, dl.peerGetRelHeadersFn(id, delay), dl.peerGetAbsHeadersFn(id, delay), dl.peerGetBodiesFn(id, delay), dl.peerGetReceiptsFn(id, delay), dl.peerGetNodeDataFn(id, delay))
+		err = dl.downloader.RegisterPeer(id, version, hashes[0], dl.peerGetRelHeadersFn(id, delay), dl.peerGetAbsHeadersFn(id, delay), dl.peerGetBodiesFn(id, delay), dl.peerGetReceiptsFn(id, delay), dl.peerGetNodeDataFn(id, delay))
 	case 64:
-		err = dl.downloader.RegisterPeer(id, version, hashes[0], nil, nil, nil, dl.peerGetRelHeadersFn(id, delay), dl.peerGetAbsHeadersFn(id, delay), dl.peerGetBodiesFn(id, delay), dl.peerGetReceiptsFn(id, delay), dl.peerGetNodeDataFn(id, delay))
+		err = dl.downloader.RegisterPeer(id, version, hashes[0], dl.peerGetRelHeadersFn(id, delay), dl.peerGetAbsHeadersFn(id, delay), dl.peerGetBodiesFn(id, delay), dl.peerGetReceiptsFn(id, delay), dl.peerGetNodeDataFn(id, delay))
 	}
 	if err == nil {
 		// Assign the owned hashes, headers and blocks to the peer (deep copy)
@@ -465,86 +463,6 @@ func (dl *downloadTester) dropPeer(id string) {
 	dl.downloader.UnregisterPeer(id)
 }
 
-// peerGetRelHashesFn constructs a GetHashes function associated with a specific
-// peer in the download tester. The returned function can be used to retrieve
-// batches of hashes from the particularly requested peer.
-func (dl *downloadTester) peerGetRelHashesFn(id string, delay time.Duration) func(head common.Hash) error {
-	return func(head common.Hash) error {
-		time.Sleep(delay)
-
-		dl.lock.RLock()
-		defer dl.lock.RUnlock()
-
-		// Gather the next batch of hashes
-		hashes := dl.peerHashes[id]
-		result := make([]common.Hash, 0, MaxHashFetch)
-		for i, hash := range hashes {
-			if hash == head {
-				i++
-				for len(result) < cap(result) && i < len(hashes) {
-					result = append(result, hashes[i])
-					i++
-				}
-				break
-			}
-		}
-		// Delay delivery a bit to allow attacks to unfold
-		go func() {
-			time.Sleep(time.Millisecond)
-			dl.downloader.DeliverHashes(id, result)
-		}()
-		return nil
-	}
-}
-
-// peerGetAbsHashesFn constructs a GetHashesFromNumber function associated with
-// a particular peer in the download tester. The returned function can be used to
-// retrieve batches of hashes from the particularly requested peer.
-func (dl *downloadTester) peerGetAbsHashesFn(id string, delay time.Duration) func(uint64, int) error {
-	return func(head uint64, count int) error {
-		time.Sleep(delay)
-
-		dl.lock.RLock()
-		defer dl.lock.RUnlock()
-
-		// Gather the next batch of hashes
-		hashes := dl.peerHashes[id]
-		result := make([]common.Hash, 0, count)
-		for i := 0; i < count && len(hashes)-int(head)-1-i >= 0; i++ {
-			result = append(result, hashes[len(hashes)-int(head)-1-i])
-		}
-		// Delay delivery a bit to allow attacks to unfold
-		go func() {
-			time.Sleep(time.Millisecond)
-			dl.downloader.DeliverHashes(id, result)
-		}()
-		return nil
-	}
-}
-
-// peerGetBlocksFn constructs a getBlocks function associated with a particular
-// peer in the download tester. The returned function can be used to retrieve
-// batches of blocks from the particularly requested peer.
-func (dl *downloadTester) peerGetBlocksFn(id string, delay time.Duration) func([]common.Hash) error {
-	return func(hashes []common.Hash) error {
-		time.Sleep(delay)
-
-		dl.lock.RLock()
-		defer dl.lock.RUnlock()
-
-		blocks := dl.peerBlocks[id]
-		result := make([]*types.Block, 0, len(hashes))
-		for _, hash := range hashes {
-			if block, ok := blocks[hash]; ok {
-				result = append(result, block)
-			}
-		}
-		go dl.downloader.DeliverBlocks(id, result)
-
-		return nil
-	}
-}
-
 // peerGetRelHeadersFn constructs a GetBlockHeaders function based on a hashed
 // origin; associated with a particular peer in the download tester. The returned
 // function can be used to retrieve batches of headers from the particular peer.
@@ -730,7 +648,6 @@ func assertOwnForkedChain(t *testing.T, tester *downloadTester, common int, leng
 // Tests that simple synchronization against a canonical chain works correctly.
 // In this test common ancestor lookup should be short circuited and not require
 // binary searching.
-func TestCanonicalSynchronisation61(t *testing.T)      { testCanonicalSynchronisation(t, 61, FullSync) }
 func TestCanonicalSynchronisation62(t *testing.T)      { testCanonicalSynchronisation(t, 62, FullSync) }
 func TestCanonicalSynchronisation63Full(t *testing.T)  { testCanonicalSynchronisation(t, 63, FullSync) }
 func TestCanonicalSynchronisation63Fast(t *testing.T)  { testCanonicalSynchronisation(t, 63, FastSync) }
@@ -759,7 +676,6 @@ func testCanonicalSynchronisation(t *testing.T, protocol int, mode SyncMode) {
 
 // Tests that if a large batch of blocks are being downloaded, it is throttled
 // until the cached blocks are retrieved.
-func TestThrottling61(t *testing.T)     { testThrottling(t, 61, FullSync) }
 func TestThrottling62(t *testing.T)     { testThrottling(t, 62, FullSync) }
 func TestThrottling63Full(t *testing.T) { testThrottling(t, 63, FullSync) }
 func TestThrottling63Fast(t *testing.T) { testThrottling(t, 63, FastSync) }
@@ -845,7 +761,6 @@ func testThrottling(t *testing.T, protocol int, mode SyncMode) {
 // Tests that simple synchronization against a forked chain works correctly. In
 // this test common ancestor lookup should *not* be short circuited, and a full
 // binary search should be executed.
-func TestForkedSync61(t *testing.T)      { testForkedSync(t, 61, FullSync) }
 func TestForkedSync62(t *testing.T)      { testForkedSync(t, 62, FullSync) }
 func TestForkedSync63Full(t *testing.T)  { testForkedSync(t, 63, FullSync) }
 func TestForkedSync63Fast(t *testing.T)  { testForkedSync(t, 63, FastSync) }
@@ -881,7 +796,6 @@ func testForkedSync(t *testing.T, protocol int, mode SyncMode) {
 
 // Tests that synchronising against a much shorter but much heavyer fork works
 // corrently and is not dropped.
-func TestHeavyForkedSync61(t *testing.T)      { testHeavyForkedSync(t, 61, FullSync) }
 func TestHeavyForkedSync62(t *testing.T)      { testHeavyForkedSync(t, 62, FullSync) }
 func TestHeavyForkedSync63Full(t *testing.T)  { testHeavyForkedSync(t, 63, FullSync) }
 func TestHeavyForkedSync63Fast(t *testing.T)  { testHeavyForkedSync(t, 63, FastSync) }
@@ -915,24 +829,9 @@ func testHeavyForkedSync(t *testing.T, protocol int, mode SyncMode) {
 	assertOwnForkedChain(t, tester, common+1, []int{common + fork + 1, common + fork/2 + 1})
 }
 
-// Tests that an inactive downloader will not accept incoming hashes and blocks.
-func TestInactiveDownloader61(t *testing.T) {
-	t.Parallel()
-	tester := newTester()
-
-	// Check that neither hashes nor blocks are accepted
-	if err := tester.downloader.DeliverHashes("bad peer", []common.Hash{}); err != errNoSyncActive {
-		t.Errorf("error mismatch: have %v, want %v", err, errNoSyncActive)
-	}
-	if err := tester.downloader.DeliverBlocks("bad peer", []*types.Block{}); err != errNoSyncActive {
-		t.Errorf("error mismatch: have %v, want %v", err, errNoSyncActive)
-	}
-}
-
 // Tests that chain forks are contained within a certain interval of the current
 // chain head, ensuring that malicious peers cannot waste resources by feeding
 // long dead chains.
-func TestBoundedForkedSync61(t *testing.T)      { testBoundedForkedSync(t, 61, FullSync) }
 func TestBoundedForkedSync62(t *testing.T)      { testBoundedForkedSync(t, 62, FullSync) }
 func TestBoundedForkedSync63Full(t *testing.T)  { testBoundedForkedSync(t, 63, FullSync) }
 func TestBoundedForkedSync63Fast(t *testing.T)  { testBoundedForkedSync(t, 63, FastSync) }
@@ -968,7 +867,6 @@ func testBoundedForkedSync(t *testing.T, protocol int, mode SyncMode) {
 // Tests that chain forks are contained within a certain interval of the current
 // chain head for short but heavy forks too. These are a bit special because they
 // take different ancestor lookup paths.
-func TestBoundedHeavyForkedSync61(t *testing.T)      { testBoundedHeavyForkedSync(t, 61, FullSync) }
 func TestBoundedHeavyForkedSync62(t *testing.T)      { testBoundedHeavyForkedSync(t, 62, FullSync) }
 func TestBoundedHeavyForkedSync63Full(t *testing.T)  { testBoundedHeavyForkedSync(t, 63, FullSync) }
 func TestBoundedHeavyForkedSync63Fast(t *testing.T)  { testBoundedHeavyForkedSync(t, 63, FastSync) }
@@ -1039,7 +937,6 @@ func TestInactiveDownloader63(t *testing.T) {
 }
 
 // Tests that a canceled download wipes all previously accumulated state.
-func TestCancel61(t *testing.T)      { testCancel(t, 61, FullSync) }
 func TestCancel62(t *testing.T)      { testCancel(t, 62, FullSync) }
 func TestCancel63Full(t *testing.T)  { testCancel(t, 63, FullSync) }
 func TestCancel63Fast(t *testing.T)  { testCancel(t, 63, FastSync) }
@@ -1081,7 +978,6 @@ func testCancel(t *testing.T, protocol int, mode SyncMode) {
 }
 
 // Tests that synchronisation from multiple peers works as intended (multi thread sanity test).
-func TestMultiSynchronisation61(t *testing.T)      { testMultiSynchronisation(t, 61, FullSync) }
 func TestMultiSynchronisation62(t *testing.T)      { testMultiSynchronisation(t, 62, FullSync) }
 func TestMultiSynchronisation63Full(t *testing.T)  { testMultiSynchronisation(t, 63, FullSync) }
 func TestMultiSynchronisation63Fast(t *testing.T)  { testMultiSynchronisation(t, 63, FastSync) }
@@ -1112,7 +1008,6 @@ func testMultiSynchronisation(t *testing.T, protocol int, mode SyncMode) {
 
 // Tests that synchronisations behave well in multi-version protocol environments
 // and not wreak havoc on other nodes in the network.
-func TestMultiProtoSynchronisation61(t *testing.T)      { testMultiProtoSync(t, 61, FullSync) }
 func TestMultiProtoSynchronisation62(t *testing.T)      { testMultiProtoSync(t, 62, FullSync) }
 func TestMultiProtoSynchronisation63Full(t *testing.T)  { testMultiProtoSync(t, 63, FullSync) }
 func TestMultiProtoSynchronisation63Fast(t *testing.T)  { testMultiProtoSync(t, 63, FastSync) }
@@ -1131,7 +1026,6 @@ func testMultiProtoSync(t *testing.T, protocol int, mode SyncMode) {
 	tester := newTester()
 	defer tester.terminate()
 
-	tester.newPeer("peer 61", 61, hashes, nil, blocks, nil)
 	tester.newPeer("peer 62", 62, hashes, headers, blocks, nil)
 	tester.newPeer("peer 63", 63, hashes, headers, blocks, receipts)
 	tester.newPeer("peer 64", 64, hashes, headers, blocks, receipts)
@@ -1143,7 +1037,7 @@ func testMultiProtoSync(t *testing.T, protocol int, mode SyncMode) {
 	assertOwnChain(t, tester, targetBlocks+1)
 
 	// Check that no peers have been dropped off
-	for _, version := range []int{61, 62, 63, 64} {
+	for _, version := range []int{62, 63, 64} {
 		peer := fmt.Sprintf("peer %d", version)
 		if _, ok := tester.peerHashes[peer]; !ok {
 			t.Errorf("%s dropped", peer)
@@ -1368,7 +1262,6 @@ func testInvalidHeaderRollback(t *testing.T, protocol int, mode SyncMode) {
 
 // Tests that a peer advertising an high TD doesn't get to stall the downloader
 // afterwards by not sending any useful hashes.
-func TestHighTDStarvationAttack61(t *testing.T)      { testHighTDStarvationAttack(t, 61, FullSync) }
 func TestHighTDStarvationAttack62(t *testing.T)      { testHighTDStarvationAttack(t, 62, FullSync) }
 func TestHighTDStarvationAttack63Full(t *testing.T)  { testHighTDStarvationAttack(t, 63, FullSync) }
 func TestHighTDStarvationAttack63Fast(t *testing.T)  { testHighTDStarvationAttack(t, 63, FastSync) }
@@ -1391,7 +1284,6 @@ func testHighTDStarvationAttack(t *testing.T, protocol int, mode SyncMode) {
 }
 
 // Tests that misbehaving peers are disconnected, whilst behaving ones are not.
-func TestBlockHeaderAttackerDropping61(t *testing.T) { testBlockHeaderAttackerDropping(t, 61) }
 func TestBlockHeaderAttackerDropping62(t *testing.T) { testBlockHeaderAttackerDropping(t, 62) }
 func TestBlockHeaderAttackerDropping63(t *testing.T) { testBlockHeaderAttackerDropping(t, 63) }
 func TestBlockHeaderAttackerDropping64(t *testing.T) { testBlockHeaderAttackerDropping(t, 64) }
@@ -1409,7 +1301,6 @@ func testBlockHeaderAttackerDropping(t *testing.T, protocol int) {
 		{errStallingPeer, true},             // Peer was detected to be stalling, drop it
 		{errNoPeers, false},                 // No peers to download from, soft race, no issue
 		{errTimeout, true},                  // No hashes received in due time, drop the peer
-		{errEmptyHashSet, true},             // No hashes were returned as a response, drop as it's a dead end
 		{errEmptyHeaderSet, true},           // No headers were returned as a response, drop as it's a dead end
 		{errPeersUnavailable, true},         // Nobody had the advertised blocks, drop the advertiser
 		{errInvalidAncestor, true},          // Agreed upon ancestor is not acceptable, drop the chain rewriter
@@ -1417,7 +1308,6 @@ func testBlockHeaderAttackerDropping(t *testing.T, protocol int) {
 		{errInvalidBlock, false},            // A bad peer was detected, but not the sync origin
 		{errInvalidBody, false},             // A bad peer was detected, but not the sync origin
 		{errInvalidReceipt, false},          // A bad peer was detected, but not the sync origin
-		{errCancelHashFetch, false},         // Synchronisation was canceled, origin may be innocent, don't drop
 		{errCancelBlockFetch, false},        // Synchronisation was canceled, origin may be innocent, don't drop
 		{errCancelHeaderFetch, false},       // Synchronisation was canceled, origin may be innocent, don't drop
 		{errCancelBodyFetch, false},         // Synchronisation was canceled, origin may be innocent, don't drop
@@ -1450,7 +1340,6 @@ func testBlockHeaderAttackerDropping(t *testing.T, protocol int) {
 
 // Tests that synchronisation progress (origin block number, current block number
 // and highest block number) is tracked and updated correctly.
-func TestSyncProgress61(t *testing.T)      { testSyncProgress(t, 61, FullSync) }
 func TestSyncProgress62(t *testing.T)      { testSyncProgress(t, 62, FullSync) }
 func TestSyncProgress63Full(t *testing.T)  { testSyncProgress(t, 63, FullSync) }
 func TestSyncProgress63Fast(t *testing.T)  { testSyncProgress(t, 63, FastSync) }
@@ -1524,7 +1413,6 @@ func testSyncProgress(t *testing.T, protocol int, mode SyncMode) {
 // Tests that synchronisation progress (origin block number and highest block
 // number) is tracked and updated correctly in case of a fork (or manual head
 // revertal).
-func TestForkedSyncProgress61(t *testing.T)      { testForkedSyncProgress(t, 61, FullSync) }
 func TestForkedSyncProgress62(t *testing.T)      { testForkedSyncProgress(t, 62, FullSync) }
 func TestForkedSyncProgress63Full(t *testing.T)  { testForkedSyncProgress(t, 63, FullSync) }
 func TestForkedSyncProgress63Fast(t *testing.T)  { testForkedSyncProgress(t, 63, FastSync) }
@@ -1601,7 +1489,6 @@ func testForkedSyncProgress(t *testing.T, protocol int, mode SyncMode) {
 // Tests that if synchronisation is aborted due to some failure, then the progress
 // origin is not updated in the next sync cycle, as it should be considered the
 // continuation of the previous sync and not a new instance.
-func TestFailedSyncProgress61(t *testing.T)      { testFailedSyncProgress(t, 61, FullSync) }
 func TestFailedSyncProgress62(t *testing.T)      { testFailedSyncProgress(t, 62, FullSync) }
 func TestFailedSyncProgress63Full(t *testing.T)  { testFailedSyncProgress(t, 63, FullSync) }
 func TestFailedSyncProgress63Fast(t *testing.T)  { testFailedSyncProgress(t, 63, FastSync) }
@@ -1679,7 +1566,6 @@ func testFailedSyncProgress(t *testing.T, protocol int, mode SyncMode) {
 
 // Tests that if an attacker fakes a chain height, after the attack is detected,
 // the progress height is successfully reduced at the next sync invocation.
-func TestFakedSyncProgress61(t *testing.T)      { testFakedSyncProgress(t, 61, FullSync) }
 func TestFakedSyncProgress62(t *testing.T)      { testFakedSyncProgress(t, 62, FullSync) }
 func TestFakedSyncProgress63Full(t *testing.T)  { testFakedSyncProgress(t, 63, FullSync) }
 func TestFakedSyncProgress63Fast(t *testing.T)  { testFakedSyncProgress(t, 63, FastSync) }
diff --git a/eth/downloader/metrics.go b/eth/downloader/metrics.go
index d6fcfa25c..0d76c7dfd 100644
--- a/eth/downloader/metrics.go
+++ b/eth/downloader/metrics.go
@@ -23,16 +23,6 @@ import (
 )
 
 var (
-	hashInMeter      = metrics.NewMeter("eth/downloader/hashes/in")
-	hashReqTimer     = metrics.NewTimer("eth/downloader/hashes/req")
-	hashDropMeter    = metrics.NewMeter("eth/downloader/hashes/drop")
-	hashTimeoutMeter = metrics.NewMeter("eth/downloader/hashes/timeout")
-
-	blockInMeter      = metrics.NewMeter("eth/downloader/blocks/in")
-	blockReqTimer     = metrics.NewTimer("eth/downloader/blocks/req")
-	blockDropMeter    = metrics.NewMeter("eth/downloader/blocks/drop")
-	blockTimeoutMeter = metrics.NewMeter("eth/downloader/blocks/timeout")
-
 	headerInMeter      = metrics.NewMeter("eth/downloader/headers/in")
 	headerReqTimer     = metrics.NewTimer("eth/downloader/headers/req")
 	headerDropMeter    = metrics.NewMeter("eth/downloader/headers/drop")
diff --git a/eth/downloader/peer.go b/eth/downloader/peer.go
index 94d44fca4..c2b7a52d0 100644
--- a/eth/downloader/peer.go
+++ b/eth/downloader/peer.go
@@ -37,11 +37,6 @@ const (
 	measurementImpact = 0.1  // The impact a single measurement has on a peer's final throughput value.
 )
 
-// Hash and block fetchers belonging to eth/61 and below
-type relativeHashFetcherFn func(common.Hash) error
-type absoluteHashFetcherFn func(uint64, int) error
-type blockFetcherFn func([]common.Hash) error
-
 // Block header and body fetchers belonging to eth/62 and above
 type relativeHeaderFetcherFn func(common.Hash, int, int, bool) error
 type absoluteHeaderFetcherFn func(uint64, int, int, bool) error
@@ -79,10 +74,6 @@ type peer struct {
 
 	lacking map[common.Hash]struct{} // Set of hashes not to request (didn't have previously)
 
-	getRelHashes relativeHashFetcherFn // [eth/61] Method to retrieve a batch of hashes from an origin hash
-	getAbsHashes absoluteHashFetcherFn // [eth/61] Method to retrieve a batch of hashes from an absolute position
-	getBlocks    blockFetcherFn        // [eth/61] Method to retrieve a batch of blocks
-
 	getRelHeaders  relativeHeaderFetcherFn // [eth/62] Method to retrieve a batch of headers from an origin hash
 	getAbsHeaders  absoluteHeaderFetcherFn // [eth/62] Method to retrieve a batch of headers from an absolute position
 	getBlockBodies blockBodyFetcherFn      // [eth/62] Method to retrieve a batch of block bodies
@@ -97,7 +88,6 @@ type peer struct {
 // newPeer create a new downloader peer, with specific hash and block retrieval
 // mechanisms.
 func newPeer(id string, version int, head common.Hash,
-	getRelHashes relativeHashFetcherFn, getAbsHashes absoluteHashFetcherFn, getBlocks blockFetcherFn, // eth/61 callbacks, remove when upgrading
 	getRelHeaders relativeHeaderFetcherFn, getAbsHeaders absoluteHeaderFetcherFn, getBlockBodies blockBodyFetcherFn,
 	getReceipts receiptFetcherFn, getNodeData stateFetcherFn) *peer {
 	return &peer{
@@ -105,10 +95,6 @@ func newPeer(id string, version int, head common.Hash,
 		head:    head,
 		lacking: make(map[common.Hash]struct{}),
 
-		getRelHashes: getRelHashes,
-		getAbsHashes: getAbsHashes,
-		getBlocks:    getBlocks,
-
 		getRelHeaders:  getRelHeaders,
 		getAbsHeaders:  getAbsHeaders,
 		getBlockBodies: getBlockBodies,
@@ -138,28 +124,6 @@ func (p *peer) Reset() {
 	p.lacking = make(map[common.Hash]struct{})
 }
 
-// Fetch61 sends a block retrieval request to the remote peer.
-func (p *peer) Fetch61(request *fetchRequest) error {
-	// Sanity check the protocol version
-	if p.version != 61 {
-		panic(fmt.Sprintf("block fetch [eth/61] requested on eth/%d", p.version))
-	}
-	// Short circuit if the peer is already fetching
-	if !atomic.CompareAndSwapInt32(&p.blockIdle, 0, 1) {
-		return errAlreadyFetching
-	}
-	p.blockStarted = time.Now()
-
-	// Convert the hash set to a retrievable slice
-	hashes := make([]common.Hash, 0, len(request.Hashes))
-	for hash, _ := range request.Hashes {
-		hashes = append(hashes, hash)
-	}
-	go p.getBlocks(hashes)
-
-	return nil
-}
-
 // FetchHeaders sends a header retrieval request to the remote peer.
 func (p *peer) FetchHeaders(from uint64, count int) error {
 	// Sanity check the protocol version
@@ -481,20 +445,6 @@ func (ps *peerSet) AllPeers() []*peer {
 	return list
 }
 
-// BlockIdlePeers retrieves a flat list of all the currently idle peers within the
-// active peer set, ordered by their reputation.
-func (ps *peerSet) BlockIdlePeers() ([]*peer, int) {
-	idle := func(p *peer) bool {
-		return atomic.LoadInt32(&p.blockIdle) == 0
-	}
-	throughput := func(p *peer) float64 {
-		p.lock.RLock()
-		defer p.lock.RUnlock()
-		return p.blockThroughput
-	}
-	return ps.idlePeers(61, 61, idle, throughput)
-}
-
 // HeaderIdlePeers retrieves a flat list of all the currently header-idle peers
 // within the active peer set, ordered by their reputation.
 func (ps *peerSet) HeaderIdlePeers() ([]*peer, int) {
diff --git a/eth/downloader/queue.go b/eth/downloader/queue.go
index 01897af6d..fd239f7e4 100644
--- a/eth/downloader/queue.go
+++ b/eth/downloader/queue.go
@@ -45,7 +45,6 @@ var (
 
 var (
 	errNoFetchesPending = errors.New("no fetches pending")
-	errStateSyncPending = errors.New("state trie sync already scheduled")
 	errStaleDelivery    = errors.New("stale delivery")
 )
 
@@ -74,10 +73,6 @@ type queue struct {
 	mode          SyncMode // Synchronisation mode to decide on the block parts to schedule for fetching
 	fastSyncPivot uint64   // Block number where the fast sync pivots into archive synchronisation mode
 
-	hashPool    map[common.Hash]int // [eth/61] Pending hashes, mapping to their insertion index (priority)
-	hashQueue   *prque.Prque        // [eth/61] Priority queue of the block hashes to fetch
-	hashCounter int                 // [eth/61] Counter indexing the added hashes to ensure retrieval order
-
 	headerHead common.Hash // [eth/62] Hash of the last queued header to verify order
 
 	// Headers are "special", they download in batches, supported by a skeleton chain
@@ -85,7 +80,6 @@ type queue struct {
 	headerTaskQueue *prque.Prque                   // [eth/62] Priority queue of the skeleton indexes to fetch the filling headers for
 	headerPeerMiss  map[string]map[uint64]struct{} // [eth/62] Set of per-peer header batches known to be unavailable
 	headerPendPool  map[string]*fetchRequest       // [eth/62] Currently pending header retrieval operations
-	headerDonePool  map[uint64]struct{}            // [eth/62] Set of the completed header fetches
 	headerResults   []*types.Header                // [eth/62] Result cache accumulating the completed headers
 	headerProced    int                            // [eth/62] Number of headers already processed from the results
 	headerOffset    uint64                         // [eth/62] Number of the first header in the result cache
@@ -124,8 +118,6 @@ type queue struct {
 func newQueue(stateDb ethdb.Database) *queue {
 	lock := new(sync.Mutex)
 	return &queue{
-		hashPool:         make(map[common.Hash]int),
-		hashQueue:        prque.New(),
 		headerPendPool:   make(map[string]*fetchRequest),
 		headerContCh:     make(chan bool),
 		blockTaskPool:    make(map[common.Hash]*types.Header),
@@ -158,10 +150,6 @@ func (q *queue) Reset() {
 	q.mode = FullSync
 	q.fastSyncPivot = 0
 
-	q.hashPool = make(map[common.Hash]int)
-	q.hashQueue.Reset()
-	q.hashCounter = 0
-
 	q.headerHead = common.Hash{}
 
 	q.headerPendPool = make(map[string]*fetchRequest)
@@ -208,7 +196,7 @@ func (q *queue) PendingBlocks() int {
 	q.lock.Lock()
 	defer q.lock.Unlock()
 
-	return q.hashQueue.Size() + q.blockTaskQueue.Size()
+	return q.blockTaskQueue.Size()
 }
 
 // PendingReceipts retrieves the number of block receipts pending for retrieval.
@@ -272,7 +260,7 @@ func (q *queue) Idle() bool {
 	q.lock.Lock()
 	defer q.lock.Unlock()
 
-	queued := q.hashQueue.Size() + q.blockTaskQueue.Size() + q.receiptTaskQueue.Size() + q.stateTaskQueue.Size()
+	queued := q.blockTaskQueue.Size() + q.receiptTaskQueue.Size() + q.stateTaskQueue.Size()
 	pending := len(q.blockPendPool) + len(q.receiptPendPool) + len(q.statePendPool)
 	cached := len(q.blockDonePool) + len(q.receiptDonePool)
 
@@ -323,34 +311,6 @@ func (q *queue) ShouldThrottleReceipts() bool {
 	return pending >= len(q.resultCache)-len(q.receiptDonePool)
 }
 
-// Schedule61 adds a set of hashes for the download queue for scheduling, returning
-// the new hashes encountered.
-func (q *queue) Schedule61(hashes []common.Hash, fifo bool) []common.Hash {
-	q.lock.Lock()
-	defer q.lock.Unlock()
-
-	// Insert all the hashes prioritised in the arrival order
-	inserts := make([]common.Hash, 0, len(hashes))
-	for _, hash := range hashes {
-		// Skip anything we already have
-		if old, ok := q.hashPool[hash]; ok {
-			glog.V(logger.Warn).Infof("Hash %x already scheduled at index %v", hash, old)
-			continue
-		}
-		// Update the counters and insert the hash
-		q.hashCounter = q.hashCounter + 1
-		inserts = append(inserts, hash)
-
-		q.hashPool[hash] = q.hashCounter
-		if fifo {
-			q.hashQueue.Push(hash, -float32(q.hashCounter)) // Lowest gets schedules first
-		} else {
-			q.hashQueue.Push(hash, float32(q.hashCounter)) // Highest gets schedules first
-		}
-	}
-	return inserts
-}
-
 // ScheduleSkeleton adds a batch of header retrieval tasks to the queue to fill
 // up an already retrieved header skeleton.
 func (q *queue) ScheduleSkeleton(from uint64, skeleton []*types.Header) {
@@ -550,15 +510,6 @@ func (q *queue) ReserveHeaders(p *peer, count int) *fetchRequest {
 	return request
 }
 
-// ReserveBlocks reserves a set of block hashes for the given peer, skipping any
-// previously failed download.
-func (q *queue) ReserveBlocks(p *peer, count int) *fetchRequest {
-	q.lock.Lock()
-	defer q.lock.Unlock()
-
-	return q.reserveHashes(p, count, q.hashQueue, nil, q.blockPendPool, len(q.resultCache)-len(q.blockDonePool))
-}
-
 // ReserveNodeData reserves a set of node data hashes for the given peer, skipping
 // any previously failed download.
 func (q *queue) ReserveNodeData(p *peer, count int) *fetchRequest {
@@ -753,11 +704,6 @@ func (q *queue) CancelHeaders(request *fetchRequest) {
 	q.cancel(request, q.headerTaskQueue, q.headerPendPool)
 }
 
-// CancelBlocks aborts a fetch request, returning all pending hashes to the queue.
-func (q *queue) CancelBlocks(request *fetchRequest) {
-	q.cancel(request, q.hashQueue, q.blockPendPool)
-}
-
 // CancelBodies aborts a body fetch request, returning all pending headers to the
 // task queue.
 func (q *queue) CancelBodies(request *fetchRequest) {
@@ -801,9 +747,6 @@ func (q *queue) Revoke(peerId string) {
 	defer q.lock.Unlock()
 
 	if request, ok := q.blockPendPool[peerId]; ok {
-		for hash, index := range request.Hashes {
-			q.hashQueue.Push(hash, float32(index))
-		}
 		for _, header := range request.Headers {
 			q.blockTaskQueue.Push(header, -float32(header.Number.Uint64()))
 		}
@@ -832,15 +775,6 @@ func (q *queue) ExpireHeaders(timeout time.Duration) map[string]int {
 	return q.expire(timeout, q.headerPendPool, q.headerTaskQueue, headerTimeoutMeter)
 }
 
-// ExpireBlocks checks for in flight requests that exceeded a timeout allowance,
-// canceling them and returning the responsible peers for penalisation.
-func (q *queue) ExpireBlocks(timeout time.Duration) map[string]int {
-	q.lock.Lock()
-	defer q.lock.Unlock()
-
-	return q.expire(timeout, q.blockPendPool, q.hashQueue, blockTimeoutMeter)
-}
-
 // ExpireBodies checks for in flight block body requests that exceeded a timeout
 // allowance, canceling them and returning the responsible peers for penalisation.
 func (q *queue) ExpireBodies(timeout time.Duration) map[string]int {
@@ -907,74 +841,6 @@ func (q *queue) expire(timeout time.Duration, pendPool map[string]*fetchRequest,
 	return expiries
 }
 
-// DeliverBlocks injects a block retrieval response into the download queue. The
-// method returns the number of blocks accepted from the delivery and also wakes
-// any threads waiting for data delivery.
-func (q *queue) DeliverBlocks(id string, blocks []*types.Block) (int, error) {
-	q.lock.Lock()
-	defer q.lock.Unlock()
-
-	// Short circuit if the blocks were never requested
-	request := q.blockPendPool[id]
-	if request == nil {
-		return 0, errNoFetchesPending
-	}
-	blockReqTimer.UpdateSince(request.Time)
-	delete(q.blockPendPool, id)
-
-	// If no blocks were retrieved, mark them as unavailable for the origin peer
-	if len(blocks) == 0 {
-		for hash, _ := range request.Hashes {
-			request.Peer.MarkLacking(hash)
-		}
-	}
-	// Iterate over the downloaded blocks and add each of them
-	accepted, errs := 0, make([]error, 0)
-	for _, block := range blocks {
-		// Skip any blocks that were not requested
-		hash := block.Hash()
-		if _, ok := request.Hashes[hash]; !ok {
-			errs = append(errs, fmt.Errorf("non-requested block %x", hash))
-			continue
-		}
-		// Reconstruct the next result if contents match up
-		index := int(block.Number().Int64() - int64(q.resultOffset))
-		if index >= len(q.resultCache) || index < 0 {
-			errs = []error{errInvalidChain}
-			break
-		}
-		q.resultCache[index] = &fetchResult{
-			Header:       block.Header(),
-			Transactions: block.Transactions(),
-			Uncles:       block.Uncles(),
-		}
-		q.blockDonePool[block.Hash()] = struct{}{}
-
-		delete(request.Hashes, hash)
-		delete(q.hashPool, hash)
-		accepted++
-	}
-	// Return all failed or missing fetches to the queue
-	for hash, index := range request.Hashes {
-		q.hashQueue.Push(hash, float32(index))
-	}
-	// Wake up WaitResults
-	if accepted > 0 {
-		q.active.Signal()
-	}
-	// If none of the blocks were good, it's a stale delivery
-	switch {
-	case len(errs) == 0:
-		return accepted, nil
-	case len(errs) == 1 && (errs[0] == errInvalidChain || errs[0] == errInvalidBlock):
-		return accepted, errs[0]
-	case len(errs) == len(blocks):
-		return accepted, errStaleDelivery
-	default:
-		return accepted, fmt.Errorf("multiple failures: %v", errs)
-	}
-}
-
 // DeliverHeaders injects a header retrieval response into the header results
 // cache. This method either accepts all headers it received, or none of them
 // if they do not map correctly to the skeleton.
diff --git a/eth/downloader/types.go b/eth/downloader/types.go
index b67fff1f8..e10510486 100644
--- a/eth/downloader/types.go
+++ b/eth/downloader/types.go
@@ -73,26 +73,6 @@ type dataPack interface {
 	Stats() string
 }
 
-// hashPack is a batch of block hashes returned by a peer (eth/61).
-type hashPack struct {
-	peerId string
-	hashes []common.Hash
-}
-
-func (p *hashPack) PeerId() string { return p.peerId }
-func (p *hashPack) Items() int     { return len(p.hashes) }
-func (p *hashPack) Stats() string  { return fmt.Sprintf("%d", len(p.hashes)) }
-
-// blockPack is a batch of blocks returned by a peer (eth/61).
-type blockPack struct {
-	peerId string
-	blocks []*types.Block
-}
-
-func (p *blockPack) PeerId() string { return p.peerId }
-func (p *blockPack) Items() int     { return len(p.blocks) }
-func (p *blockPack) Stats() string  { return fmt.Sprintf("%d", len(p.blocks)) }
-
 // headerPack is a batch of block headers returned by a peer.
 type headerPack struct {
 	peerId  string