eth: port the synchronisation algo to eth/62

2 files changed, 767 insertions, 105 deletions

diff --git a/eth/fetcher/fetcher.go b/eth/fetcher/fetcher.go
index 07eb165dc..f54256788 100644
--- a/eth/fetcher/fetcher.go
+++ b/eth/fetcher/fetcher.go
@@ -51,6 +51,12 @@ type blockRetrievalFn func(common.Hash) *types.Block
 // blockRequesterFn is a callback type for sending a block retrieval request.
 type blockRequesterFn func([]common.Hash) error
 
+// headerRequesterFn is a callback type for sending a header retrieval request.
+type headerRequesterFn func(common.Hash) error
+
+// bodyRequesterFn is a callback type for sending a body retrieval request.
+type bodyRequesterFn func([]common.Hash) error
+
 // blockValidatorFn is a callback type to verify a block's header for fast propagation.
 type blockValidatorFn func(block *types.Block, parent *types.Block) error
 
@@ -69,12 +75,30 @@ type peerDropFn func(id string)
 // announce is the hash notification of the availability of a new block in the
 // network.
 type announce struct {
-	hash   common.Hash // Hash of the block being announced
-	number uint64      // Number of the block being announced (0 = unknown | old protocol)
-	time   time.Time   // Timestamp of the announcement
+	hash   common.Hash   // Hash of the block being announced
+	number uint64        // Number of the block being announced (0 = unknown | old protocol)
+	header *types.Header // Header of the block partially reassembled (new protocol)
+	time   time.Time     // Timestamp of the announcement
+
+	origin string // Identifier of the peer originating the notification
+
+	fetch61     blockRequesterFn  // [eth/61] Fetcher function to retrieve an announced block
+	fetchHeader headerRequesterFn // [eth/62] Fetcher function to retrieve the header of an announced block
+	fetchBodies bodyRequesterFn   // [eth/62] Fetcher function to retrieve the body of an announced block
+}
 
-	origin string           // Identifier of the peer originating the notification
-	fetch  blockRequesterFn // Fetcher function to retrieve
+// headerFilterTask represents a batch of headers needing fetcher filtering.
+type headerFilterTask struct {
+	headers []*types.Header // Collection of headers to filter
+	time    time.Time       // Arrival time of the headers
+}
+
+// headerFilterTask represents a batch of block bodies (transactions and uncles)
+// needing fetcher filtering.
+type bodyFilterTask struct {
+	transactions [][]*types.Transaction // Collection of transactions per block bodies
+	uncles       [][]*types.Header      // Collection of uncles per block bodies
+	time         time.Time              // Arrival time of the blocks' contents
 }
 
 // inject represents a schedules import operation.
@@ -89,14 +113,20 @@ type Fetcher struct {
 	// Various event channels
 	notify chan *announce
 	inject chan *inject
-	filter chan chan []*types.Block
-	done   chan common.Hash
-	quit   chan struct{}
+
+	blockFilter  chan chan []*types.Block
+	headerFilter chan chan *headerFilterTask
+	bodyFilter   chan chan *bodyFilterTask
+
+	done chan common.Hash
+	quit chan struct{}
 
 	// Announce states
-	announces map[string]int              // Per peer announce counts to prevent memory exhaustion
-	announced map[common.Hash][]*announce // Announced blocks, scheduled for fetching
-	fetching  map[common.Hash]*announce   // Announced blocks, currently fetching
+	announces  map[string]int              // Per peer announce counts to prevent memory exhaustion
+	announced  map[common.Hash][]*announce // Announced blocks, scheduled for fetching
+	fetching   map[common.Hash]*announce   // Announced blocks, currently fetching
+	fetched    map[common.Hash][]*announce // Blocks with headers fetched, scheduled for body retrieval
+	completing map[common.Hash]*announce   // Blocks with headers, currently body-completing
 
 	// Block cache
 	queue  *prque.Prque            // Queue containing the import operations (block number sorted)
@@ -112,8 +142,9 @@ type Fetcher struct {
 	dropPeer       peerDropFn         // Drops a peer for misbehaving
 
 	// Testing hooks
-	fetchingHook func([]common.Hash) // Method to call upon starting a block fetch
-	importedHook func(*types.Block)  // Method to call upon successful block import
+	fetchingHook   func([]common.Hash) // Method to call upon starting a block (eth/61) or header (eth/62) fetch
+	completingHook func([]common.Hash) // Method to call upon starting a block body fetch (eth/62)
+	importedHook   func(*types.Block)  // Method to call upon successful block import (both eth/61 and eth/62)
 }
 
 // New creates a block fetcher to retrieve blocks based on hash announcements.
@@ -121,12 +152,16 @@ func New(getBlock blockRetrievalFn, validateBlock blockValidatorFn, broadcastBlo
 	return &Fetcher{
 		notify:         make(chan *announce),
 		inject:         make(chan *inject),
-		filter:         make(chan chan []*types.Block),
+		blockFilter:    make(chan chan []*types.Block),
+		headerFilter:   make(chan chan *headerFilterTask),
+		bodyFilter:     make(chan chan *bodyFilterTask),
 		done:           make(chan common.Hash),
 		quit:           make(chan struct{}),
 		announces:      make(map[string]int),
 		announced:      make(map[common.Hash][]*announce),
 		fetching:       make(map[common.Hash]*announce),
+		fetched:        make(map[common.Hash][]*announce),
+		completing:     make(map[common.Hash]*announce),
 		queue:          prque.New(),
 		queues:         make(map[string]int),
 		queued:         make(map[common.Hash]*inject),
@@ -153,13 +188,17 @@ func (f *Fetcher) Stop() {
 
 // Notify announces the fetcher of the potential availability of a new block in
 // the network.
-func (f *Fetcher) Notify(peer string, hash common.Hash, number uint64, time time.Time, fetcher blockRequesterFn) error {
+func (f *Fetcher) Notify(peer string, hash common.Hash, number uint64, time time.Time,
+	blockFetcher blockRequesterFn, // eth/61 specific whole block fetcher
+	headerFetcher headerRequesterFn, bodyFetcher bodyRequesterFn) error {
 	block := &announce{
-		hash:   hash,
-		number: number,
-		time:   time,
-		origin: peer,
-		fetch:  fetcher,
+		hash:        hash,
+		number:      number,
+		time:        time,
+		origin:      peer,
+		fetch61:     blockFetcher,
+		fetchHeader: headerFetcher,
+		fetchBodies: bodyFetcher,
 	}
 	select {
 	case f.notify <- block:
@@ -183,14 +222,16 @@ func (f *Fetcher) Enqueue(peer string, block *types.Block) error {
 	}
 }
 
-// Filter extracts all the blocks that were explicitly requested by the fetcher,
+// FilterBlocks extracts all the blocks that were explicitly requested by the fetcher,
 // returning those that should be handled differently.
-func (f *Fetcher) Filter(blocks types.Blocks) types.Blocks {
+func (f *Fetcher) FilterBlocks(blocks types.Blocks) types.Blocks {
+	glog.V(logger.Detail).Infof("[eth/61] filtering %d blocks", len(blocks))
+
 	// Send the filter channel to the fetcher
 	filter := make(chan []*types.Block)
 
 	select {
-	case f.filter <- filter:
+	case f.blockFilter <- filter:
 	case <-f.quit:
 		return nil
 	}
@@ -209,11 +250,69 @@ func (f *Fetcher) Filter(blocks types.Blocks) types.Blocks {
 	}
 }
 
+// FilterHeaders extracts all the headers that were explicitly requested by the fetcher,
+// returning those that should be handled differently.
+func (f *Fetcher) FilterHeaders(headers []*types.Header, time time.Time) []*types.Header {
+	glog.V(logger.Detail).Infof("[eth/62] filtering %d headers", len(headers))
+
+	// Send the filter channel to the fetcher
+	filter := make(chan *headerFilterTask)
+
+	select {
+	case f.headerFilter <- filter:
+	case <-f.quit:
+		return nil
+	}
+	// Request the filtering of the header list
+	select {
+	case filter <- &headerFilterTask{headers: headers, time: time}:
+	case <-f.quit:
+		return nil
+	}
+	// Retrieve the headers remaining after filtering
+	select {
+	case task := <-filter:
+		return task.headers
+	case <-f.quit:
+		return nil
+	}
+}
+
+// FilterBodies extracts all the block bodies that were explicitly requested by
+// the fetcher, returning those that should be handled differently.
+func (f *Fetcher) FilterBodies(transactions [][]*types.Transaction, uncles [][]*types.Header, time time.Time) ([][]*types.Transaction, [][]*types.Header) {
+	glog.V(logger.Detail).Infof("[eth/62] filtering %d:%d bodies", len(transactions), len(uncles))
+
+	// Send the filter channel to the fetcher
+	filter := make(chan *bodyFilterTask)
+
+	select {
+	case f.bodyFilter <- filter:
+	case <-f.quit:
+		return nil, nil
+	}
+	// Request the filtering of the body list
+	select {
+	case filter <- &bodyFilterTask{transactions: transactions, uncles: uncles, time: time}:
+	case <-f.quit:
+		return nil, nil
+	}
+	// Retrieve the bodies remaining after filtering
+	select {
+	case task := <-filter:
+		return task.transactions, task.uncles
+	case <-f.quit:
+		return nil, nil
+	}
+}
+
 // Loop is the main fetcher loop, checking and processing various notification
 // events.
 func (f *Fetcher) loop() {
 	// Iterate the block fetching until a quit is requested
-	fetch := time.NewTimer(0)
+	fetchTimer := time.NewTimer(0)
+	completeTimer := time.NewTimer(0)
+
 	for {
 		// Clean up any expired block fetches
 		for hash, announce := range f.fetching {
@@ -255,14 +354,25 @@ func (f *Fetcher) loop() {
 				glog.V(logger.Debug).Infof("Peer %s: exceeded outstanding announces (%d)", notification.origin, hashLimit)
 				break
 			}
+			// If we have a valid block number, check that it's potentially useful
+			if notification.number > 0 {
+				if dist := int64(notification.number) - int64(f.chainHeight()); dist < -maxUncleDist || dist > maxQueueDist {
+					glog.V(logger.Debug).Infof("[eth/62] Peer %s: discarded announcement #%d [%x…], distance %d", notification.origin, notification.number, notification.hash[:4], dist)
+					discardMeter.Mark(1)
+					break
+				}
+			}
 			// All is well, schedule the announce if block's not yet downloading
 			if _, ok := f.fetching[notification.hash]; ok {
 				break
 			}
+			if _, ok := f.completing[notification.hash]; ok {
+				break
+			}
 			f.announces[notification.origin] = count
 			f.announced[notification.hash] = append(f.announced[notification.hash], notification)
 			if len(f.announced) == 1 {
-				f.reschedule(fetch)
+				f.rescheduleFetch(fetchTimer)
 			}
 
 		case op := <-f.inject:
@@ -275,7 +385,7 @@ func (f *Fetcher) loop() {
 			f.forgetHash(hash)
 			f.forgetBlock(hash)
 
-		case <-fetch.C:
+		case <-fetchTimer.C:
 			// At least one block's timer ran out, check for needing retrieval
 			request := make(map[string][]common.Hash)
 
@@ -292,30 +402,77 @@ func (f *Fetcher) loop() {
 					}
 				}
 			}
-			// Send out all block requests
+			// Send out all block (eth/61) or header (eth/62) requests
 			for peer, hashes := range request {
 				if glog.V(logger.Detail) && len(hashes) > 0 {
 					list := "["
 					for _, hash := range hashes {
-						list += fmt.Sprintf("%x, ", hash[:4])
+						list += fmt.Sprintf("%x…, ", hash[:4])
 					}
 					list = list[:len(list)-2] + "]"
 
-					glog.V(logger.Detail).Infof("Peer %s: fetching %s", peer, list)
+					if f.fetching[hashes[0]].fetch61 != nil {
+						glog.V(logger.Detail).Infof("[eth/61] Peer %s: fetching blocks %s", peer, list)
+					} else {
+						glog.V(logger.Detail).Infof("[eth/62] Peer %s: fetching headers %s", peer, list)
+					}
 				}
 				// Create a closure of the fetch and schedule in on a new thread
-				fetcher, hashes := f.fetching[hashes[0]].fetch, hashes
+				fetchBlocks, fetchHeader, hashes := f.fetching[hashes[0]].fetch61, f.fetching[hashes[0]].fetchHeader, hashes
 				go func() {
 					if f.fetchingHook != nil {
 						f.fetchingHook(hashes)
 					}
-					fetcher(hashes)
+					if fetchBlocks != nil {
+						// Use old eth/61 protocol to retrieve whole blocks
+						fetchBlocks(hashes)
+					} else {
+						// Use new eth/62 protocol to retrieve headers first
+						for _, hash := range hashes {
+							fetchHeader(hash) // Suboptimal, but protocol doesn't allow batch header retrievals
+						}
+					}
 				}()
 			}
 			// Schedule the next fetch if blocks are still pending
-			f.reschedule(fetch)
+			f.rescheduleFetch(fetchTimer)
 
-		case filter := <-f.filter:
+		case <-completeTimer.C:
+			// At least one header's timer ran out, retrieve everything
+			request := make(map[string][]common.Hash)
+
+			for hash, announces := range f.fetched {
+				// Pick a random peer to retrieve from, reset all others
+				announce := announces[rand.Intn(len(announces))]
+				f.forgetHash(hash)
+
+				// If the block still didn't arrive, queue for completion
+				if f.getBlock(hash) == nil {
+					request[announce.origin] = append(request[announce.origin], hash)
+					f.completing[hash] = announce
+				}
+			}
+			// Send out all block body requests
+			for peer, hashes := range request {
+				if glog.V(logger.Detail) && len(hashes) > 0 {
+					list := "["
+					for _, hash := range hashes {
+						list += fmt.Sprintf("%x…, ", hash[:4])
+					}
+					list = list[:len(list)-2] + "]"
+
+					glog.V(logger.Detail).Infof("[eth/62] Peer %s: fetching bodies %s", peer, list)
+				}
+				// Create a closure of the fetch and schedule in on a new thread
+				if f.completingHook != nil {
+					f.completingHook(hashes)
+				}
+				go f.completing[hashes[0]].fetchBodies(hashes)
+			}
+			// Schedule the next fetch if blocks are still pending
+			f.rescheduleComplete(completeTimer)
+
+		case filter := <-f.blockFilter:
 			// Blocks arrived, extract any explicit fetches, return all else
 			var blocks types.Blocks
 			select {
@@ -352,12 +509,135 @@ func (f *Fetcher) loop() {
 					f.enqueue(announce.origin, block)
 				}
 			}
+
+		case filter := <-f.headerFilter:
+			// Headers arrived from a remote peer. Extract those that were explicitly
+			// requested by the fetcher, and return everything else so it's delivered
+			// to other parts of the system.
+			var task *headerFilterTask
+			select {
+			case task = <-filter:
+			case <-f.quit:
+				return
+			}
+			// Split the batch of headers into unknown ones (to return to the caller),
+			// known incomplete ones (requiring body retrievals) and completed blocks.
+			unknown, incomplete, complete := []*types.Header{}, []*announce{}, []*types.Block{}
+			for _, header := range task.headers {
+				hash := header.Hash()
+
+				// Filter fetcher-requested headers from other synchronisation algorithms
+				if announce := f.fetching[hash]; announce != nil && f.fetched[hash] == nil && f.completing[hash] == nil && f.queued[hash] == nil {
+					// If the delivered header does not match the promised number, drop the announcer
+					if header.Number.Uint64() != announce.number {
+						glog.V(logger.Detail).Infof("[eth/62] Peer %s: invalid block number for [%x…]: announced %d, provided %d", announce.origin, header.Hash().Bytes()[:4], announce.number, header.Number.Uint64())
+						f.dropPeer(announce.origin)
+						f.forgetHash(hash)
+						continue
+					}
+					// Only keep if not imported by other means
+					if f.getBlock(hash) == nil {
+						announce.header = header
+						announce.time = task.time
+
+						// If the block is empty (header only), short circuit into the final import queue
+						if header.TxHash == types.DeriveSha(types.Transactions{}) && header.UncleHash == types.CalcUncleHash([]*types.Header{}) {
+							glog.V(logger.Detail).Infof("[eth/62] Peer %s: block #%d [%x…] empty, skipping body retrieval", announce.origin, header.Number.Uint64(), header.Hash().Bytes()[:4])
+
+							complete = append(complete, types.NewBlockWithHeader(header))
+							f.completing[hash] = announce
+							continue
+						}
+						// Otherwise add to the list of blocks needing completion
+						incomplete = append(incomplete, announce)
+					} else {
+						glog.V(logger.Detail).Infof("[eth/62] Peer %s: block #%d [%x…] already imported, discarding header", announce.origin, header.Number.Uint64(), header.Hash().Bytes()[:4])
+						f.forgetHash(hash)
+					}
+				} else {
+					// Fetcher doesn't know about it, add to the return list
+					unknown = append(unknown, header)
+				}
+			}
+			select {
+			case filter <- &headerFilterTask{headers: unknown, time: task.time}:
+			case <-f.quit:
+				return
+			}
+			// Schedule the retrieved headers for body completion
+			for _, announce := range incomplete {
+				hash := announce.header.Hash()
+				if _, ok := f.completing[hash]; ok {
+					continue
+				}
+				f.fetched[hash] = append(f.fetched[hash], announce)
+				if len(f.fetched) == 1 {
+					f.rescheduleComplete(completeTimer)
+				}
+			}
+			// Schedule the header-only blocks for import
+			for _, block := range complete {
+				if announce := f.completing[block.Hash()]; announce != nil {
+					f.enqueue(announce.origin, block)
+				}
+			}
+
+		case filter := <-f.bodyFilter:
+			// Block bodies arrived, extract any explicitly requested blocks, return the rest
+			var task *bodyFilterTask
+			select {
+			case task = <-filter:
+			case <-f.quit:
+				return
+			}
+
+			blocks := []*types.Block{}
+			for i := 0; i < len(task.transactions) && i < len(task.uncles); i++ {
+				// Match up a body to any possible completion request
+				matched := false
+
+				for hash, announce := range f.completing {
+					if f.queued[hash] == nil {
+						txnHash := types.DeriveSha(types.Transactions(task.transactions[i]))
+						uncleHash := types.CalcUncleHash(task.uncles[i])
+
+						if txnHash == announce.header.TxHash && uncleHash == announce.header.UncleHash {
+							// Mark the body matched, reassemble if still unknown
+							matched = true
+
+							if f.getBlock(hash) == nil {
+								blocks = append(blocks, types.NewBlockWithHeader(announce.header).WithBody(task.transactions[i], task.uncles[i]))
+							} else {
+								f.forgetHash(hash)
+							}
+						}
+					}
+				}
+				if matched {
+					task.transactions = append(task.transactions[:i], task.transactions[i+1:]...)
+					task.uncles = append(task.uncles[:i], task.uncles[i+1:]...)
+					i--
+					continue
+				}
+			}
+
+			select {
+			case filter <- task:
+			case <-f.quit:
+				return
+			}
+			// Schedule the retrieved blocks for ordered import
+			for _, block := range blocks {
+				if announce := f.completing[block.Hash()]; announce != nil {
+					f.enqueue(announce.origin, block)
+				}
+			}
 		}
 	}
 }
 
-// reschedule resets the specified fetch timer to the next announce timeout.
-func (f *Fetcher) reschedule(fetch *time.Timer) {
+// rescheduleFetch resets the specified fetch timer to the next announce timeout.
+func (f *Fetcher) rescheduleFetch(fetch *time.Timer) {
 	// Short circuit if no blocks are announced
 	if len(f.announced) == 0 {
 		return
@@ -372,6 +652,22 @@ func (f *Fetcher) reschedule(fetch *time.Timer) {
 	fetch.Reset(arriveTimeout - time.Since(earliest))
 }
 
+// rescheduleComplete resets the specified completion timer to the next fetch timeout.
+func (f *Fetcher) rescheduleComplete(complete *time.Timer) {
+	// Short circuit if no headers are fetched
+	if len(f.fetched) == 0 {
+		return
+	}
+	// Otherwise find the earliest expiring announcement
+	earliest := time.Now()
+	for _, announces := range f.fetched {
+		if earliest.After(announces[0].time) {
+			earliest = announces[0].time
+		}
+	}
+	complete.Reset(gatherSlack - time.Since(earliest))
+}
+
 // enqueue schedules a new future import operation, if the block to be imported
 // has not yet been seen.
 func (f *Fetcher) enqueue(peer string, block *types.Block) {
@@ -380,13 +676,15 @@ func (f *Fetcher) enqueue(peer string, block *types.Block) {
 	// Ensure the peer isn't DOSing us
 	count := f.queues[peer] + 1
 	if count > blockLimit {
-		glog.V(logger.Debug).Infof("Peer %s: discarded block #%d [%x], exceeded allowance (%d)", peer, block.NumberU64(), hash.Bytes()[:4], blockLimit)
+		glog.V(logger.Debug).Infof("Peer %s: discarded block #%d [%x…], exceeded allowance (%d)", peer, block.NumberU64(), hash.Bytes()[:4], blockLimit)
+		f.forgetHash(hash)
 		return
 	}
 	// Discard any past or too distant blocks
 	if dist := int64(block.NumberU64()) - int64(f.chainHeight()); dist < -maxUncleDist || dist > maxQueueDist {
-		glog.V(logger.Debug).Infof("Peer %s: discarded block #%d [%x], distance %d", peer, block.NumberU64(), hash.Bytes()[:4], dist)
+		glog.V(logger.Debug).Infof("Peer %s: discarded block #%d [%x…], distance %d", peer, block.NumberU64(), hash.Bytes()[:4], dist)
 		discardMeter.Mark(1)
+		f.forgetHash(hash)
 		return
 	}
 	// Schedule the block for future importing
@@ -400,7 +698,7 @@ func (f *Fetcher) enqueue(peer string, block *types.Block) {
 		f.queue.Push(op, -float32(block.NumberU64()))
 
 		if glog.V(logger.Debug) {
-			glog.Infof("Peer %s: queued block #%d [%x], total %v", peer, block.NumberU64(), hash.Bytes()[:4], f.queue.Size())
+			glog.Infof("Peer %s: queued block #%d [%x…], total %v", peer, block.NumberU64(), hash.Bytes()[:4], f.queue.Size())
 		}
 	}
 }
@@ -412,13 +710,14 @@ func (f *Fetcher) insert(peer string, block *types.Block) {
 	hash := block.Hash()
 
 	// Run the import on a new thread
-	glog.V(logger.Debug).Infof("Peer %s: importing block #%d [%x]", peer, block.NumberU64(), hash[:4])
+	glog.V(logger.Debug).Infof("Peer %s: importing block #%d [%x…]", peer, block.NumberU64(), hash[:4])
 	go func() {
 		defer func() { f.done <- hash }()
 
 		// If the parent's unknown, abort insertion
 		parent := f.getBlock(block.ParentHash())
 		if parent == nil {
+			glog.V(logger.Debug).Infof("Peer %s: parent []%x] of block #%d [%x…] unknown", block.ParentHash().Bytes()[:4], peer, block.NumberU64(), hash[:4])
 			return
 		}
 		// Quickly validate the header and propagate the block if it passes
@@ -434,13 +733,13 @@ func (f *Fetcher) insert(peer string, block *types.Block) {
 
 		default:
 			// Something went very wrong, drop the peer
-			glog.V(logger.Debug).Infof("Peer %s: block #%d [%x] verification failed: %v", peer, block.NumberU64(), hash[:4], err)
+			glog.V(logger.Debug).Infof("Peer %s: block #%d [%x…] verification failed: %v", peer, block.NumberU64(), hash[:4], err)
 			f.dropPeer(peer)
 			return
 		}
 		// Run the actual import and log any issues
 		if _, err := f.insertChain(types.Blocks{block}); err != nil {
-			glog.V(logger.Warn).Infof("Peer %s: block #%d [%x] import failed: %v", peer, block.NumberU64(), hash[:4], err)
+			glog.V(logger.Warn).Infof("Peer %s: block #%d [%x…] import failed: %v", peer, block.NumberU64(), hash[:4], err)
 			return
 		}
 		// If import succeeded, broadcast the block
@@ -474,9 +773,27 @@ func (f *Fetcher) forgetHash(hash common.Hash) {
 		}
 		delete(f.fetching, hash)
 	}
+
+	// Remove any pending completion requests and decrement the DOS counters
+	for _, announce := range f.fetched[hash] {
+		f.announces[announce.origin]--
+		if f.announces[announce.origin] == 0 {
+			delete(f.announces, announce.origin)
+		}
+	}
+	delete(f.fetched, hash)
+
+	// Remove any pending completions and decrement the DOS counters
+	if announce := f.completing[hash]; announce != nil {
+		f.announces[announce.origin]--
+		if f.announces[announce.origin] == 0 {
+			delete(f.announces, announce.origin)
+		}
+		delete(f.completing, hash)
+	}
 }
 
-// forgetBlock removes all traces of a queued block frmo the fetcher's internal
+// forgetBlock removes all traces of a queued block from the fetcher's internal
 // state.
 func (f *Fetcher) forgetBlock(hash common.Hash) {
 	if insert := f.queued[hash]; insert != nil {
diff --git a/eth/fetcher/fetcher_test.go b/eth/fetcher/fetcher_test.go
index b0d9ce843..707d8d758 100644
--- a/eth/fetcher/fetcher_test.go
+++ b/eth/fetcher/fetcher_test.go
@@ -27,21 +27,39 @@ import (
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/ethdb"
 	"github.com/ethereum/go-ethereum/params"
 )
 
 var (
 	testdb, _    = ethdb.NewMemDatabase()
-	genesis      = core.GenesisBlockForTesting(testdb, common.Address{}, big.NewInt(0))
+	testKey, _   = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
+	testAddress  = crypto.PubkeyToAddress(testKey.PublicKey)
+	genesis      = core.GenesisBlockForTesting(testdb, testAddress, big.NewInt(1000000000))
 	unknownBlock = types.NewBlock(&types.Header{GasLimit: params.GenesisGasLimit}, nil, nil, nil)
 )
 
 // makeChain creates a chain of n blocks starting at and including parent.
-// the returned hash chain is ordered head->parent.
+// the returned hash chain is ordered head->parent. In addition, every 3rd block
+// contains a transaction and every 5th an uncle to allow testing correct block
+// reassembly.
 func makeChain(n int, seed byte, parent *types.Block) ([]common.Hash, map[common.Hash]*types.Block) {
-	blocks := core.GenerateChain(parent, testdb, n, func(i int, gen *core.BlockGen) {
-		gen.SetCoinbase(common.Address{seed})
+	blocks := core.GenerateChain(parent, testdb, n, func(i int, block *core.BlockGen) {
+		block.SetCoinbase(common.Address{seed})
+
+		// If the block number is multiple of 3, send a bonus transaction to the miner
+		if parent == genesis && i%3 == 0 {
+			tx, err := types.NewTransaction(block.TxNonce(testAddress), common.Address{seed}, big.NewInt(1000), params.TxGas, nil, nil).SignECDSA(testKey)
+			if err != nil {
+				panic(err)
+			}
+			block.AddTx(tx)
+		}
+		// If the block number is a multiple of 5, add a bonus uncle to the block
+		if i%5 == 0 {
+			block.AddUncle(&types.Header{ParentHash: block.PrevBlock(i - 1).Hash(), Number: big.NewInt(int64(i - 1))})
+		}
 	})
 	hashes := make([]common.Hash, n+1)
 	hashes[len(hashes)-1] = parent.Hash()
@@ -60,6 +78,7 @@ type fetcherTester struct {
 
 	hashes []common.Hash                // Hash chain belonging to the tester
 	blocks map[common.Hash]*types.Block // Blocks belonging to the tester
+	drops  map[string]bool              // Map of peers dropped by the fetcher
 
 	lock sync.RWMutex
 }
@@ -69,6 +88,7 @@ func newTester() *fetcherTester {
 	tester := &fetcherTester{
 		hashes: []common.Hash{genesis.Hash()},
 		blocks: map[common.Hash]*types.Block{genesis.Hash(): genesis},
+		drops:  make(map[string]bool),
 	}
 	tester.fetcher = New(tester.getBlock, tester.verifyBlock, tester.broadcastBlock, tester.chainHeight, tester.insertChain, tester.dropPeer)
 	tester.fetcher.Start()
@@ -122,12 +142,14 @@ func (f *fetcherTester) insertChain(blocks types.Blocks) (int, error) {
 	return 0, nil
 }
 
-// dropPeer is a nop placeholder for the peer removal.
+// dropPeer is an emulator for the peer removal, simply accumulating the various
+// peers dropped by the fetcher.
 func (f *fetcherTester) dropPeer(peer string) {
+	f.drops[peer] = true
 }
 
-// peerFetcher retrieves a fetcher associated with a simulated peer.
-func (f *fetcherTester) makeFetcher(blocks map[common.Hash]*types.Block) blockRequesterFn {
+// makeBlockFetcher retrieves a block fetcher associated with a simulated peer.
+func (f *fetcherTester) makeBlockFetcher(blocks map[common.Hash]*types.Block) blockRequesterFn {
 	closure := make(map[common.Hash]*types.Block)
 	for hash, block := range blocks {
 		closure[hash] = block
@@ -142,18 +164,105 @@ func (f *fetcherTester) makeFetcher(blocks map[common.Hash]*types.Block) blockRe
 			}
 		}
 		// Return on a new thread
-		go f.fetcher.Filter(blocks)
+		go f.fetcher.FilterBlocks(blocks)
+
+		return nil
+	}
+}
+
+// makeHeaderFetcher retrieves a block header fetcher associated with a simulated peer.
+func (f *fetcherTester) makeHeaderFetcher(blocks map[common.Hash]*types.Block, drift time.Duration) headerRequesterFn {
+	closure := make(map[common.Hash]*types.Block)
+	for hash, block := range blocks {
+		closure[hash] = block
+	}
+	// Create a function that return a header from the closure
+	return func(hash common.Hash) error {
+		// Gather the blocks to return
+		headers := make([]*types.Header, 0, 1)
+		if block, ok := closure[hash]; ok {
+			headers = append(headers, block.Header())
+		}
+		// Return on a new thread
+		go f.fetcher.FilterHeaders(headers, time.Now().Add(drift))
+
+		return nil
+	}
+}
+
+// makeBodyFetcher retrieves a block body fetcher associated with a simulated peer.
+func (f *fetcherTester) makeBodyFetcher(blocks map[common.Hash]*types.Block, drift time.Duration) bodyRequesterFn {
+	closure := make(map[common.Hash]*types.Block)
+	for hash, block := range blocks {
+		closure[hash] = block
+	}
+	// Create a function that returns blocks from the closure
+	return func(hashes []common.Hash) error {
+		// Gather the block bodies to return
+		transactions := make([][]*types.Transaction, 0, len(hashes))
+		uncles := make([][]*types.Header, 0, len(hashes))
+
+		for _, hash := range hashes {
+			if block, ok := closure[hash]; ok {
+				transactions = append(transactions, block.Transactions())
+				uncles = append(uncles, block.Uncles())
+			}
+		}
+		// Return on a new thread
+		go f.fetcher.FilterBodies(transactions, uncles, time.Now().Add(drift))
 
 		return nil
 	}
 }
 
+// verifyFetchingEvent verifies that one single event arrive on an fetching channel.
+func verifyFetchingEvent(t *testing.T, fetching chan []common.Hash, arrive bool) {
+	if arrive {
+		select {
+		case <-fetching:
+		case <-time.After(time.Second):
+			t.Fatalf("fetching timeout")
+		}
+	} else {
+		select {
+		case <-fetching:
+			t.Fatalf("fetching invoked")
+		case <-time.After(10 * time.Millisecond):
+		}
+	}
+}
+
+// verifyCompletingEvent verifies that one single event arrive on an completing channel.
+func verifyCompletingEvent(t *testing.T, completing chan []common.Hash, arrive bool) {
+	if arrive {
+		select {
+		case <-completing:
+		case <-time.After(time.Second):
+			t.Fatalf("completing timeout")
+		}
+	} else {
+		select {
+		case <-completing:
+			t.Fatalf("completing invoked")
+		case <-time.After(10 * time.Millisecond):
+		}
+	}
+}
+
 // verifyImportEvent verifies that one single event arrive on an import channel.
-func verifyImportEvent(t *testing.T, imported chan *types.Block) {
-	select {
-	case <-imported:
-	case <-time.After(time.Second):
-		t.Fatalf("import timeout")
+func verifyImportEvent(t *testing.T, imported chan *types.Block, arrive bool) {
+	if arrive {
+		select {
+		case <-imported:
+		case <-time.After(time.Second):
+			t.Fatalf("import timeout")
+		}
+	} else {
+		select {
+		case <-imported:
+			t.Fatalf("import invoked")
+		case <-time.After(10 * time.Millisecond):
+		}
 	}
 }
 
@@ -164,7 +273,7 @@ func verifyImportCount(t *testing.T, imported chan *types.Block, count int) {
 		select {
 		case <-imported:
 		case <-time.After(time.Second):
-			t.Fatalf("block %d: import timeout", i)
+			t.Fatalf("block %d: import timeout", i+1)
 		}
 	}
 	verifyImportDone(t, imported)
@@ -181,51 +290,78 @@ func verifyImportDone(t *testing.T, imported chan *types.Block) {
 
 // Tests that a fetcher accepts block announcements and initiates retrievals for
 // them, successfully importing into the local chain.
-func TestSequentialAnnouncements(t *testing.T) {
+func TestSequentialAnnouncements61(t *testing.T) { testSequentialAnnouncements(t, 61) }
+func TestSequentialAnnouncements62(t *testing.T) { testSequentialAnnouncements(t, 62) }
+func TestSequentialAnnouncements63(t *testing.T) { testSequentialAnnouncements(t, 63) }
+func TestSequentialAnnouncements64(t *testing.T) { testSequentialAnnouncements(t, 64) }
+
+func testSequentialAnnouncements(t *testing.T, protocol int) {
 	// Create a chain of blocks to import
 	targetBlocks := 4 * hashLimit
 	hashes, blocks := makeChain(targetBlocks, 0, genesis)
 
 	tester := newTester()
-	fetcher := tester.makeFetcher(blocks)
+	blockFetcher := tester.makeBlockFetcher(blocks)
+	headerFetcher := tester.makeHeaderFetcher(blocks, -gatherSlack)
+	bodyFetcher := tester.makeBodyFetcher(blocks, 0)
 
 	// Iteratively announce blocks until all are imported
 	imported := make(chan *types.Block)
 	tester.fetcher.importedHook = func(block *types.Block) { imported <- block }
 
 	for i := len(hashes) - 2; i >= 0; i-- {
-		tester.fetcher.Notify("valid", hashes[i], 0, time.Now().Add(-arriveTimeout), fetcher)
-		verifyImportEvent(t, imported)
+		if protocol < 62 {
+			tester.fetcher.Notify("valid", hashes[i], 0, time.Now().Add(-arriveTimeout), blockFetcher, nil, nil)
+		} else {
+			tester.fetcher.Notify("valid", hashes[i], uint64(len(hashes)-i-1), time.Now().Add(-arriveTimeout), nil, headerFetcher, bodyFetcher)
+		}
+		verifyImportEvent(t, imported, true)
 	}
 	verifyImportDone(t, imported)
 }
 
 // Tests that if blocks are announced by multiple peers (or even the same buggy
 // peer), they will only get downloaded at most once.
-func TestConcurrentAnnouncements(t *testing.T) {
+func TestConcurrentAnnouncements61(t *testing.T) { testConcurrentAnnouncements(t, 61) }
+func TestConcurrentAnnouncements62(t *testing.T) { testConcurrentAnnouncements(t, 62) }
+func TestConcurrentAnnouncements63(t *testing.T) { testConcurrentAnnouncements(t, 63) }
+func TestConcurrentAnnouncements64(t *testing.T) { testConcurrentAnnouncements(t, 64) }
+
+func testConcurrentAnnouncements(t *testing.T, protocol int) {
 	// Create a chain of blocks to import
 	targetBlocks := 4 * hashLimit
 	hashes, blocks := makeChain(targetBlocks, 0, genesis)
 
 	// Assemble a tester with a built in counter for the requests
 	tester := newTester()
-	fetcher := tester.makeFetcher(blocks)
+	blockFetcher := tester.makeBlockFetcher(blocks)
+	headerFetcher := tester.makeHeaderFetcher(blocks, -gatherSlack)
+	bodyFetcher := tester.makeBodyFetcher(blocks, 0)
 
 	counter := uint32(0)
-	wrapper := func(hashes []common.Hash) error {
+	blockWrapper := func(hashes []common.Hash) error {
 		atomic.AddUint32(&counter, uint32(len(hashes)))
-		return fetcher(hashes)
+		return blockFetcher(hashes)
+	}
+	headerWrapper := func(hash common.Hash) error {
+		atomic.AddUint32(&counter, 1)
+		return headerFetcher(hash)
 	}
 	// Iteratively announce blocks until all are imported
 	imported := make(chan *types.Block)
 	tester.fetcher.importedHook = func(block *types.Block) { imported <- block }
 
 	for i := len(hashes) - 2; i >= 0; i-- {
-		tester.fetcher.Notify("first", hashes[i], 0, time.Now().Add(-arriveTimeout), wrapper)
-		tester.fetcher.Notify("second", hashes[i], 0, time.Now().Add(-arriveTimeout+time.Millisecond), wrapper)
-		tester.fetcher.Notify("second", hashes[i], 0, time.Now().Add(-arriveTimeout-time.Millisecond), wrapper)
-
-		verifyImportEvent(t, imported)
+		if protocol < 62 {
+			tester.fetcher.Notify("first", hashes[i], 0, time.Now().Add(-arriveTimeout), blockWrapper, nil, nil)
+			tester.fetcher.Notify("second", hashes[i], 0, time.Now().Add(-arriveTimeout+time.Millisecond), blockWrapper, nil, nil)
+			tester.fetcher.Notify("second", hashes[i], 0, time.Now().Add(-arriveTimeout-time.Millisecond), blockWrapper, nil, nil)
+		} else {
+			tester.fetcher.Notify("first", hashes[i], uint64(len(hashes)-i-1), time.Now().Add(-arriveTimeout), nil, headerWrapper, bodyFetcher)
+			tester.fetcher.Notify("second", hashes[i], uint64(len(hashes)-i-1), time.Now().Add(-arriveTimeout+time.Millisecond), nil, headerWrapper, bodyFetcher)
+			tester.fetcher.Notify("second", hashes[i], uint64(len(hashes)-i-1), time.Now().Add(-arriveTimeout-time.Millisecond), nil, headerWrapper, bodyFetcher)
+		}
+		verifyImportEvent(t, imported, true)
 	}
 	verifyImportDone(t, imported)
 
@@ -237,56 +373,90 @@ func TestConcurrentAnnouncements(t *testing.T) {
 
 // Tests that announcements arriving while a previous is being fetched still
 // results in a valid import.
-func TestOverlappingAnnouncements(t *testing.T) {
+func TestOverlappingAnnouncements61(t *testing.T) { testOverlappingAnnouncements(t, 61) }
+func TestOverlappingAnnouncements62(t *testing.T) { testOverlappingAnnouncements(t, 62) }
+func TestOverlappingAnnouncements63(t *testing.T) { testOverlappingAnnouncements(t, 63) }
+func TestOverlappingAnnouncements64(t *testing.T) { testOverlappingAnnouncements(t, 64) }
+
+func testOverlappingAnnouncements(t *testing.T, protocol int) {
 	// Create a chain of blocks to import
 	targetBlocks := 4 * hashLimit
 	hashes, blocks := makeChain(targetBlocks, 0, genesis)
 
 	tester := newTester()
-	fetcher := tester.makeFetcher(blocks)
+	blockFetcher := tester.makeBlockFetcher(blocks)
+	headerFetcher := tester.makeHeaderFetcher(blocks, -gatherSlack)
+	bodyFetcher := tester.makeBodyFetcher(blocks, 0)
 
 	// Iteratively announce blocks, but overlap them continuously
-	fetching := make(chan []common.Hash)
+	overlap := 16
 	imported := make(chan *types.Block, len(hashes)-1)
-	tester.fetcher.fetchingHook = func(hashes []common.Hash) { fetching <- hashes }
+	for i := 0; i < overlap; i++ {
+		imported <- nil
+	}
 	tester.fetcher.importedHook = func(block *types.Block) { imported <- block }
 
 	for i := len(hashes) - 2; i >= 0; i-- {
-		tester.fetcher.Notify("valid", hashes[i], 0, time.Now().Add(-arriveTimeout), fetcher)
+		if protocol < 62 {
+			tester.fetcher.Notify("valid", hashes[i], 0, time.Now().Add(-arriveTimeout), blockFetcher, nil, nil)
+		} else {
+			tester.fetcher.Notify("valid", hashes[i], uint64(len(hashes)-i-1), time.Now().Add(-arriveTimeout), nil, headerFetcher, bodyFetcher)
+		}
 		select {
-		case <-fetching:
+		case <-imported:
 		case <-time.After(time.Second):
-			t.Fatalf("hash %d: announce timeout", len(hashes)-i)
+			t.Fatalf("block %d: import timeout", len(hashes)-i)
 		}
 	}
 	// Wait for all the imports to complete and check count
-	verifyImportCount(t, imported, len(hashes)-1)
+	verifyImportCount(t, imported, overlap)
 }
 
 // Tests that announces already being retrieved will not be duplicated.
-func TestPendingDeduplication(t *testing.T) {
+func TestPendingDeduplication61(t *testing.T) { testPendingDeduplication(t, 61) }
+func TestPendingDeduplication62(t *testing.T) { testPendingDeduplication(t, 62) }
+func TestPendingDeduplication63(t *testing.T) { testPendingDeduplication(t, 63) }
+func TestPendingDeduplication64(t *testing.T) { testPendingDeduplication(t, 64) }
+
+func testPendingDeduplication(t *testing.T, protocol int) {
 	// Create a hash and corresponding block
 	hashes, blocks := makeChain(1, 0, genesis)
 
 	// Assemble a tester with a built in counter and delayed fetcher
 	tester := newTester()
-	fetcher := tester.makeFetcher(blocks)
+	blockFetcher := tester.makeBlockFetcher(blocks)
+	headerFetcher := tester.makeHeaderFetcher(blocks, -gatherSlack)
+	bodyFetcher := tester.makeBodyFetcher(blocks, 0)
 
 	delay := 50 * time.Millisecond
 	counter := uint32(0)
-	wrapper := func(hashes []common.Hash) error {
+	blockWrapper := func(hashes []common.Hash) error {
 		atomic.AddUint32(&counter, uint32(len(hashes)))
 
 		// Simulate a long running fetch
 		go func() {
 			time.Sleep(delay)
-			fetcher(hashes)
+			blockFetcher(hashes)
+		}()
+		return nil
+	}
+	headerWrapper := func(hash common.Hash) error {
+		atomic.AddUint32(&counter, 1)
+
+		// Simulate a long running fetch
+		go func() {
+			time.Sleep(delay)
+			headerFetcher(hash)
 		}()
 		return nil
 	}
 	// Announce the same block many times until it's fetched (wait for any pending ops)
 	for tester.getBlock(hashes[0]) == nil {
-		tester.fetcher.Notify("repeater", hashes[0], 0, time.Now().Add(-arriveTimeout), wrapper)
+		if protocol < 62 {
+			tester.fetcher.Notify("repeater", hashes[0], 0, time.Now().Add(-arriveTimeout), blockWrapper, nil, nil)
+		} else {
+			tester.fetcher.Notify("repeater", hashes[0], 1, time.Now().Add(-arriveTimeout), nil, headerWrapper, bodyFetcher)
+		}
 		time.Sleep(time.Millisecond)
 	}
 	time.Sleep(delay)
@@ -302,14 +472,21 @@ func TestPendingDeduplication(t *testing.T) {
 
 // Tests that announcements retrieved in a random order are cached and eventually
 // imported when all the gaps are filled in.
-func TestRandomArrivalImport(t *testing.T) {
+func TestRandomArrivalImport61(t *testing.T) { testRandomArrivalImport(t, 61) }
+func TestRandomArrivalImport62(t *testing.T) { testRandomArrivalImport(t, 62) }
+func TestRandomArrivalImport63(t *testing.T) { testRandomArrivalImport(t, 63) }
+func TestRandomArrivalImport64(t *testing.T) { testRandomArrivalImport(t, 64) }
+
+func testRandomArrivalImport(t *testing.T, protocol int) {
 	// Create a chain of blocks to import, and choose one to delay
 	targetBlocks := maxQueueDist
 	hashes, blocks := makeChain(targetBlocks, 0, genesis)
 	skip := targetBlocks / 2
 
 	tester := newTester()
-	fetcher := tester.makeFetcher(blocks)
+	blockFetcher := tester.makeBlockFetcher(blocks)
+	headerFetcher := tester.makeHeaderFetcher(blocks, -gatherSlack)
+	bodyFetcher := tester.makeBodyFetcher(blocks, 0)
 
 	// Iteratively announce blocks, skipping one entry
 	imported := make(chan *types.Block, len(hashes)-1)
@@ -317,25 +494,40 @@ func TestRandomArrivalImport(t *testing.T) {
 
 	for i := len(hashes) - 1; i >= 0; i-- {
 		if i != skip {
-			tester.fetcher.Notify("valid", hashes[i], 0, time.Now().Add(-arriveTimeout), fetcher)
+			if protocol < 62 {
+				tester.fetcher.Notify("valid", hashes[i], 0, time.Now().Add(-arriveTimeout), blockFetcher, nil, nil)
+			} else {
+				tester.fetcher.Notify("valid", hashes[i], uint64(len(hashes)-i-1), time.Now().Add(-arriveTimeout), nil, headerFetcher, bodyFetcher)
+			}
 			time.Sleep(time.Millisecond)
 		}
 	}
 	// Finally announce the skipped entry and check full import
-	tester.fetcher.Notify("valid", hashes[skip], 0, time.Now().Add(-arriveTimeout), fetcher)
+	if protocol < 62 {
+		tester.fetcher.Notify("valid", hashes[skip], 0, time.Now().Add(-arriveTimeout), blockFetcher, nil, nil)
+	} else {
+		tester.fetcher.Notify("valid", hashes[skip], uint64(len(hashes)-skip-1), time.Now().Add(-arriveTimeout), nil, headerFetcher, bodyFetcher)
+	}
 	verifyImportCount(t, imported, len(hashes)-1)
 }
 
 // Tests that direct block enqueues (due to block propagation vs. hash announce)
 // are correctly schedule, filling and import queue gaps.
-func TestQueueGapFill(t *testing.T) {
+func TestQueueGapFill61(t *testing.T) { testQueueGapFill(t, 61) }
+func TestQueueGapFill62(t *testing.T) { testQueueGapFill(t, 62) }
+func TestQueueGapFill63(t *testing.T) { testQueueGapFill(t, 63) }
+func TestQueueGapFill64(t *testing.T) { testQueueGapFill(t, 64) }
+
+func testQueueGapFill(t *testing.T, protocol int) {
 	// Create a chain of blocks to import, and choose one to not announce at all
 	targetBlocks := maxQueueDist
 	hashes, blocks := makeChain(targetBlocks, 0, genesis)
 	skip := targetBlocks / 2
 
 	tester := newTester()
-	fetcher := tester.makeFetcher(blocks)
+	blockFetcher := tester.makeBlockFetcher(blocks)
+	headerFetcher := tester.makeHeaderFetcher(blocks, -gatherSlack)
+	bodyFetcher := tester.makeBodyFetcher(blocks, 0)
 
 	// Iteratively announce blocks, skipping one entry
 	imported := make(chan *types.Block, len(hashes)-1)
@@ -343,7 +535,11 @@ func TestQueueGapFill(t *testing.T) {
 
 	for i := len(hashes) - 1; i >= 0; i-- {
 		if i != skip {
-			tester.fetcher.Notify("valid", hashes[i], 0, time.Now().Add(-arriveTimeout), fetcher)
+			if protocol < 62 {
+				tester.fetcher.Notify("valid", hashes[i], 0, time.Now().Add(-arriveTimeout), blockFetcher, nil, nil)
+			} else {
+				tester.fetcher.Notify("valid", hashes[i], uint64(len(hashes)-i-1), time.Now().Add(-arriveTimeout), nil, headerFetcher, bodyFetcher)
+			}
 			time.Sleep(time.Millisecond)
 		}
 	}
@@ -354,13 +550,20 @@ func TestQueueGapFill(t *testing.T) {
 
 // Tests that blocks arriving from various sources (multiple propagations, hash
 // announces, etc) do not get scheduled for import multiple times.
-func TestImportDeduplication(t *testing.T) {
+func TestImportDeduplication61(t *testing.T) { testImportDeduplication(t, 61) }
+func TestImportDeduplication62(t *testing.T) { testImportDeduplication(t, 62) }
+func TestImportDeduplication63(t *testing.T) { testImportDeduplication(t, 63) }
+func TestImportDeduplication64(t *testing.T) { testImportDeduplication(t, 64) }
+
+func testImportDeduplication(t *testing.T, protocol int) {
 	// Create two blocks to import (one for duplication, the other for stalling)
 	hashes, blocks := makeChain(2, 0, genesis)
 
 	// Create the tester and wrap the importer with a counter
 	tester := newTester()
-	fetcher := tester.makeFetcher(blocks)
+	blockFetcher := tester.makeBlockFetcher(blocks)
+	headerFetcher := tester.makeHeaderFetcher(blocks, -gatherSlack)
+	bodyFetcher := tester.makeBodyFetcher(blocks, 0)
 
 	counter := uint32(0)
 	tester.fetcher.insertChain = func(blocks types.Blocks) (int, error) {
@@ -374,7 +577,11 @@ func TestImportDeduplication(t *testing.T) {
 	tester.fetcher.importedHook = func(block *types.Block) { imported <- block }
 
 	// Announce the duplicating block, wait for retrieval, and also propagate directly
-	tester.fetcher.Notify("valid", hashes[0], 0, time.Now().Add(-arriveTimeout), fetcher)
+	if protocol < 62 {
+		tester.fetcher.Notify("valid", hashes[0], 0, time.Now().Add(-arriveTimeout), blockFetcher, nil, nil)
+	} else {
+		tester.fetcher.Notify("valid", hashes[0], 1, time.Now().Add(-arriveTimeout), nil, headerFetcher, bodyFetcher)
+	}
 	<-fetching
 
 	tester.fetcher.Enqueue("valid", blocks[hashes[0]])
@@ -391,35 +598,157 @@ func TestImportDeduplication(t *testing.T) {
 }
 
 // Tests that blocks with numbers much lower or higher than out current head get
-// discarded no prevent wasting resources on useless blocks from faulty peers.
-func TestDistantDiscarding(t *testing.T) {
-	// Create a long chain to import
+// discarded to prevent wasting resources on useless blocks from faulty peers.
+func TestDistantPropagationDiscarding(t *testing.T) {
+	// Create a long chain to import and define the discard boundaries
 	hashes, blocks := makeChain(3*maxQueueDist, 0, genesis)
 	head := hashes[len(hashes)/2]
 
+	low, high := len(hashes)/2+maxUncleDist+1, len(hashes)/2-maxQueueDist-1
+
 	// Create a tester and simulate a head block being the middle of the above chain
 	tester := newTester()
 	tester.hashes = []common.Hash{head}
 	tester.blocks = map[common.Hash]*types.Block{head: blocks[head]}
 
 	// Ensure that a block with a lower number than the threshold is discarded
-	tester.fetcher.Enqueue("lower", blocks[hashes[0]])
+	tester.fetcher.Enqueue("lower", blocks[hashes[low]])
 	time.Sleep(10 * time.Millisecond)
 	if !tester.fetcher.queue.Empty() {
 		t.Fatalf("fetcher queued stale block")
 	}
 	// Ensure that a block with a higher number than the threshold is discarded
-	tester.fetcher.Enqueue("higher", blocks[hashes[len(hashes)-1]])
+	tester.fetcher.Enqueue("higher", blocks[hashes[high]])
 	time.Sleep(10 * time.Millisecond)
 	if !tester.fetcher.queue.Empty() {
 		t.Fatalf("fetcher queued future block")
 	}
 }
 
+// Tests that announcements with numbers much lower or higher than out current
+// head get discarded to prevent wasting resources on useless blocks from faulty
+// peers.
+func TestDistantAnnouncementDiscarding62(t *testing.T) { testDistantAnnouncementDiscarding(t, 62) }
+func TestDistantAnnouncementDiscarding63(t *testing.T) { testDistantAnnouncementDiscarding(t, 63) }
+func TestDistantAnnouncementDiscarding64(t *testing.T) { testDistantAnnouncementDiscarding(t, 64) }
+
+func testDistantAnnouncementDiscarding(t *testing.T, protocol int) {
+	// Create a long chain to import and define the discard boundaries
+	hashes, blocks := makeChain(3*maxQueueDist, 0, genesis)
+	head := hashes[len(hashes)/2]
+
+	low, high := len(hashes)/2+maxUncleDist+1, len(hashes)/2-maxQueueDist-1
+
+	// Create a tester and simulate a head block being the middle of the above chain
+	tester := newTester()
+	tester.hashes = []common.Hash{head}
+	tester.blocks = map[common.Hash]*types.Block{head: blocks[head]}
+
+	headerFetcher := tester.makeHeaderFetcher(blocks, -gatherSlack)
+	bodyFetcher := tester.makeBodyFetcher(blocks, 0)
+
+	fetching := make(chan struct{}, 2)
+	tester.fetcher.fetchingHook = func(hashes []common.Hash) { fetching <- struct{}{} }
+
+	// Ensure that a block with a lower number than the threshold is discarded
+	tester.fetcher.Notify("lower", hashes[low], blocks[hashes[low]].NumberU64(), time.Now().Add(-arriveTimeout), nil, headerFetcher, bodyFetcher)
+	select {
+	case <-time.After(50 * time.Millisecond):
+	case <-fetching:
+		t.Fatalf("fetcher requested stale header")
+	}
+	// Ensure that a block with a higher number than the threshold is discarded
+	tester.fetcher.Notify("higher", hashes[high], blocks[hashes[high]].NumberU64(), time.Now().Add(-arriveTimeout), nil, headerFetcher, bodyFetcher)
+	select {
+	case <-time.After(50 * time.Millisecond):
+	case <-fetching:
+		t.Fatalf("fetcher requested future header")
+	}
+}
+
+// Tests that peers announcing blocks with invalid numbers (i.e. not matching
+// the headers provided afterwards) get dropped as malicious.
+func TestInvalidNumberAnnouncement62(t *testing.T) { testInvalidNumberAnnouncement(t, 62) }
+func TestInvalidNumberAnnouncement63(t *testing.T) { testInvalidNumberAnnouncement(t, 63) }
+func TestInvalidNumberAnnouncement64(t *testing.T) { testInvalidNumberAnnouncement(t, 64) }
+
+func testInvalidNumberAnnouncement(t *testing.T, protocol int) {
+	// Create a single block to import and check numbers against
+	hashes, blocks := makeChain(1, 0, genesis)
+
+	tester := newTester()
+	headerFetcher := tester.makeHeaderFetcher(blocks, -gatherSlack)
+	bodyFetcher := tester.makeBodyFetcher(blocks, 0)
+
+	imported := make(chan *types.Block)
+	tester.fetcher.importedHook = func(block *types.Block) { imported <- block }
+
+	// Announce a block with a bad number, check for immediate drop
+	tester.fetcher.Notify("bad", hashes[0], 2, time.Now().Add(-arriveTimeout), nil, headerFetcher, bodyFetcher)
+	verifyImportEvent(t, imported, false)
+
+	if !tester.drops["bad"] {
+		t.Fatalf("peer with invalid numbered announcement not dropped")
+	}
+	// Make sure a good announcement passes without a drop
+	tester.fetcher.Notify("good", hashes[0], 1, time.Now().Add(-arriveTimeout), nil, headerFetcher, bodyFetcher)
+	verifyImportEvent(t, imported, true)
+
+	if tester.drops["good"] {
+		t.Fatalf("peer with valid numbered announcement dropped")
+	}
+	verifyImportDone(t, imported)
+}
+
+// Tests that if a block is empty (i.e. header only), no body request should be
+// made, and instead the header should be assembled into a whole block in itself.
+func TestEmptyBlockShortCircuit62(t *testing.T) { testEmptyBlockShortCircuit(t, 62) }
+func TestEmptyBlockShortCircuit63(t *testing.T) { testEmptyBlockShortCircuit(t, 63) }
+func TestEmptyBlockShortCircuit64(t *testing.T) { testEmptyBlockShortCircuit(t, 64) }
+
+func testEmptyBlockShortCircuit(t *testing.T, protocol int) {
+	// Create a chain of blocks to import
+	hashes, blocks := makeChain(32, 0, genesis)
+
+	tester := newTester()
+	headerFetcher := tester.makeHeaderFetcher(blocks, -gatherSlack)
+	bodyFetcher := tester.makeBodyFetcher(blocks, 0)
+
+	// Add a monitoring hook for all internal events
+	fetching := make(chan []common.Hash)
+	tester.fetcher.fetchingHook = func(hashes []common.Hash) { fetching <- hashes }
+
+	completing := make(chan []common.Hash)
+	tester.fetcher.completingHook = func(hashes []common.Hash) { completing <- hashes }
+
+	imported := make(chan *types.Block)
+	tester.fetcher.importedHook = func(block *types.Block) { imported <- block }
+
+	// Iteratively announce blocks until all are imported
+	for i := len(hashes) - 2; i >= 0; i-- {
+		tester.fetcher.Notify("valid", hashes[i], uint64(len(hashes)-i-1), time.Now().Add(-arriveTimeout), nil, headerFetcher, bodyFetcher)
+
+		// All announces should fetch the header
+		verifyFetchingEvent(t, fetching, true)
+
+		// Only blocks with data contents should request bodies
+		verifyCompletingEvent(t, completing, len(blocks[hashes[i]].Transactions()) > 0 || len(blocks[hashes[i]].Uncles()) > 0)
+
+		// Irrelevant of the construct, import should succeed
+		verifyImportEvent(t, imported, true)
+	}
+	verifyImportDone(t, imported)
+}
+
 // Tests that a peer is unable to use unbounded memory with sending infinite
 // block announcements to a node, but that even in the face of such an attack,
 // the fetcher remains operational.
-func TestHashMemoryExhaustionAttack(t *testing.T) {
+func TestHashMemoryExhaustionAttack61(t *testing.T) { testHashMemoryExhaustionAttack(t, 61) }
+func TestHashMemoryExhaustionAttack62(t *testing.T) { testHashMemoryExhaustionAttack(t, 62) }
+func TestHashMemoryExhaustionAttack63(t *testing.T) { testHashMemoryExhaustionAttack(t, 63) }
+func TestHashMemoryExhaustionAttack64(t *testing.T) { testHashMemoryExhaustionAttack(t, 64) }
+
+func testHashMemoryExhaustionAttack(t *testing.T, protocol int) {
 	// Create a tester with instrumented import hooks
 	tester := newTester()
 
@@ -429,17 +758,29 @@ func TestHashMemoryExhaustionAttack(t *testing.T) {
 	// Create a valid chain and an infinite junk chain
 	targetBlocks := hashLimit + 2*maxQueueDist
 	hashes, blocks := makeChain(targetBlocks, 0, genesis)
-	valid := tester.makeFetcher(blocks)
+	validBlockFetcher := tester.makeBlockFetcher(blocks)
+	validHeaderFetcher := tester.makeHeaderFetcher(blocks, -gatherSlack)
+	validBodyFetcher := tester.makeBodyFetcher(blocks, 0)
 
 	attack, _ := makeChain(targetBlocks, 0, unknownBlock)
-	attacker := tester.makeFetcher(nil)
+	attackerBlockFetcher := tester.makeBlockFetcher(nil)
+	attackerHeaderFetcher := tester.makeHeaderFetcher(nil, -gatherSlack)
+	attackerBodyFetcher := tester.makeBodyFetcher(nil, 0)
 
 	// Feed the tester a huge hashset from the attacker, and a limited from the valid peer
 	for i := 0; i < len(attack); i++ {
 		if i < maxQueueDist {
-			tester.fetcher.Notify("valid", hashes[len(hashes)-2-i], 0, time.Now(), valid)
+			if protocol < 62 {
+				tester.fetcher.Notify("valid", hashes[len(hashes)-2-i], 0, time.Now(), validBlockFetcher, nil, nil)
+			} else {
+				tester.fetcher.Notify("valid", hashes[len(hashes)-2-i], uint64(i+1), time.Now(), nil, validHeaderFetcher, validBodyFetcher)
+			}
+		}
+		if protocol < 62 {
+			tester.fetcher.Notify("attacker", attack[i], 0, time.Now(), attackerBlockFetcher, nil, nil)
+		} else {
+			tester.fetcher.Notify("attacker", attack[i], 1 /* don't distance drop */, time.Now(), nil, attackerHeaderFetcher, attackerBodyFetcher)
 		}
-		tester.fetcher.Notify("attacker", attack[i], 0, time.Now(), attacker)
 	}
 	if len(tester.fetcher.announced) != hashLimit+maxQueueDist {
 		t.Fatalf("queued announce count mismatch: have %d, want %d", len(tester.fetcher.announced), hashLimit+maxQueueDist)
@@ -449,8 +790,12 @@ func TestHashMemoryExhaustionAttack(t *testing.T) {
 
 	// Feed the remaining valid hashes to ensure DOS protection state remains clean
 	for i := len(hashes) - maxQueueDist - 2; i >= 0; i-- {
-		tester.fetcher.Notify("valid", hashes[i], 0, time.Now().Add(-arriveTimeout), valid)
-		verifyImportEvent(t, imported)
+		if protocol < 62 {
+			tester.fetcher.Notify("valid", hashes[i], 0, time.Now().Add(-arriveTimeout), validBlockFetcher, nil, nil)
+		} else {
+			tester.fetcher.Notify("valid", hashes[i], uint64(len(hashes)-i-1), time.Now().Add(-arriveTimeout), nil, validHeaderFetcher, validBodyFetcher)
+		}
+		verifyImportEvent(t, imported, true)
 	}
 	verifyImportDone(t, imported)
 }
@@ -498,7 +843,7 @@ func TestBlockMemoryExhaustionAttack(t *testing.T) {
 	// Insert the remaining blocks in chunks to ensure clean DOS protection
 	for i := maxQueueDist; i < len(hashes)-1; i++ {
 		tester.fetcher.Enqueue("valid", blocks[hashes[len(hashes)-2-i]])
-		verifyImportEvent(t, imported)
+		verifyImportEvent(t, imported, true)
 	}
 	verifyImportDone(t, imported)
 }