eth/downloader: add fast and light sync strategies

core/transaction_util.go

@@ -140,13 +140,12 @@ func GetBlockReceipts(db ethdb.Database, hash common.Hash) types.Receipts {
 	if len(data) == 0 {
 		return nil
 	}
-
+	receipts := new(types.Receipts)
-	var receipts types.Receipts
+	if err := rlp.DecodeBytes(data, receipts); err != nil {
-	err := rlp.DecodeBytes(data, &receipts)
+		glog.V(logger.Error).Infof("invalid receipt array RLP for hash %x: %v", hash, err)
-	if err != nil {
+		return nil
-		glog.V(logger.Core).Infoln("GetReceiptse err", err)
 	}
-	return receipts
+	return *receipts
 }
 
 // PutBlockReceipts stores the block's transactions associated receipts

core/types/block.go

@@ -172,8 +172,8 @@ type storageblock struct {
 }
 
 var (
-	emptyRootHash  = DeriveSha(Transactions{})
+	EmptyRootHash  = DeriveSha(Transactions{})
-	emptyUncleHash = CalcUncleHash(nil)
+	EmptyUncleHash = CalcUncleHash(nil)
 )
 
 // NewBlock creates a new block. The input data is copied,
@@ -188,7 +188,7 @@ func NewBlock(header *Header, txs []*Transaction, uncles []*Header, receipts []*
 
 	// TODO: panic if len(txs) != len(receipts)
 	if len(txs) == 0 {
-		b.header.TxHash = emptyRootHash
+		b.header.TxHash = EmptyRootHash
 	} else {
 		b.header.TxHash = DeriveSha(Transactions(txs))
 		b.transactions = make(Transactions, len(txs))
@@ -196,7 +196,7 @@ func NewBlock(header *Header, txs []*Transaction, uncles []*Header, receipts []*
 	}
 
 	if len(receipts) == 0 {
-		b.header.ReceiptHash = emptyRootHash
+		b.header.ReceiptHash = EmptyRootHash
 	} else {
 		b.header.ReceiptHash = DeriveSha(Receipts(receipts))
 		b.header.Bloom = CreateBloom(receipts)
@@ -205,7 +205,7 @@ func NewBlock(header *Header, txs []*Transaction, uncles []*Header, receipts []*
 	}
 
 	if len(uncles) == 0 {
-		b.header.UncleHash = emptyUncleHash
+		b.header.UncleHash = EmptyUncleHash
 	} else {
 		b.header.UncleHash = CalcUncleHash(uncles)
 		b.uncles = make([]*Header, len(uncles))

eth/downloader/metrics.go

@@ -42,4 +42,9 @@ var (
 	bodyReqTimer     = metrics.NewTimer("eth/downloader/bodies/req")
 	bodyDropMeter    = metrics.NewMeter("eth/downloader/bodies/drop")
 	bodyTimeoutMeter = metrics.NewMeter("eth/downloader/bodies/timeout")
+
+	receiptInMeter      = metrics.NewMeter("eth/downloader/receipts/in")
+	receiptReqTimer     = metrics.NewTimer("eth/downloader/receipts/req")
+	receiptDropMeter    = metrics.NewMeter("eth/downloader/receipts/drop")
+	receiptTimeoutMeter = metrics.NewMeter("eth/downloader/receipts/timeout")
 )

eth/downloader/modes.go

@@ -0,0 +1,26 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package downloader
+
+// SyncMode represents the synchronisation mode of the downloader.
+type SyncMode int
+
+const (
+	FullSync  SyncMode = iota // Synchronise the entire block-chain history from full blocks
+	FastSync                  // Quikcly download the headers, full sync only at the chain head
+	LightSync                 // Download only the headers and terminate afterwards
+)

eth/downloader/peer.go

@@ -36,10 +36,11 @@ type relativeHashFetcherFn func(common.Hash) error
 type absoluteHashFetcherFn func(uint64, int) error
 type blockFetcherFn func([]common.Hash) error
 
-// Block header and body fethers belonging to eth/62 and above
+// 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
 type blockBodyFetcherFn func([]common.Hash) error
+type receiptFetcherFn func([]common.Hash) error
 
 var (
 	errAlreadyFetching   = errors.New("already fetching blocks from peer")
@@ -52,11 +53,14 @@ type peer struct {
 	id   string      // Unique identifier of the peer
 	head common.Hash // Hash of the peers latest known block
 
-	idle int32 // Current activity state of the peer (idle = 0, active = 1)
+	blockIdle   int32 // Current block activity state of the peer (idle = 0, active = 1)
+	receiptIdle int32 // Current receipt activity state of the peer (idle = 0, active = 1)
 	rep         int32 // Simple peer reputation
 
-	capacity int32     // Number of blocks allowed to fetch per request
+	blockCapacity   int32     // Number of blocks (bodies) allowed to fetch per request
-	started  time.Time // Time instance when the last fetch was started
+	receiptCapacity int32     // Number of receipts allowed to fetch per request
+	blockStarted    time.Time // Time instance when the last block (body)fetch was started
+	receiptStarted  time.Time // Time instance when the last receipt fetch was started
 
 	ignored *set.Set // Set of hashes not to request (didn't have previously)
 
@@ -68,6 +72,8 @@ type peer struct {
 	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
 
+	getReceipts receiptFetcherFn // [eth/63] Method to retrieve a batch of block transaction receipts
+
 	version int // Eth protocol version number to switch strategies
 }
 
@@ -75,11 +81,13 @@ type peer struct {
 // 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) *peer {
+	getRelHeaders relativeHeaderFetcherFn, getAbsHeaders absoluteHeaderFetcherFn, getBlockBodies blockBodyFetcherFn,
+	getReceipts receiptFetcherFn) *peer {
 	return &peer{
 		id:              id,
 		head:            head,
-		capacity: 1,
+		blockCapacity:   1,
+		receiptCapacity: 1,
 		ignored:         set.New(),
 
 		getRelHashes: getRelHashes,
@@ -90,24 +98,28 @@ func newPeer(id string, version int, head common.Hash,
 		getAbsHeaders:  getAbsHeaders,
 		getBlockBodies: getBlockBodies,
 
+		getReceipts: getReceipts,
+
 		version: version,
 	}
 }
 
 // Reset clears the internal state of a peer entity.
 func (p *peer) Reset() {
-	atomic.StoreInt32(&p.idle, 0)
+	atomic.StoreInt32(&p.blockIdle, 0)
-	atomic.StoreInt32(&p.capacity, 1)
+	atomic.StoreInt32(&p.receiptIdle, 0)
+	atomic.StoreInt32(&p.blockCapacity, 1)
+	atomic.StoreInt32(&p.receiptCapacity, 1)
 	p.ignored.Clear()
 }
 
 // Fetch61 sends a block retrieval request to the remote peer.
 func (p *peer) Fetch61(request *fetchRequest) error {
 	// Short circuit if the peer is already fetching
-	if !atomic.CompareAndSwapInt32(&p.idle, 0, 1) {
+	if !atomic.CompareAndSwapInt32(&p.blockIdle, 0, 1) {
 		return errAlreadyFetching
 	}
-	p.started = time.Now()
+	p.blockStarted = time.Now()
 
 	// Convert the hash set to a retrievable slice
 	hashes := make([]common.Hash, 0, len(request.Hashes))
@@ -119,13 +131,13 @@ func (p *peer) Fetch61(request *fetchRequest) error {
 	return nil
 }
 
-// Fetch sends a block body retrieval request to the remote peer.
+// FetchBodies sends a block body retrieval request to the remote peer.
-func (p *peer) Fetch(request *fetchRequest) error {
+func (p *peer) FetchBodies(request *fetchRequest) error {
 	// Short circuit if the peer is already fetching
-	if !atomic.CompareAndSwapInt32(&p.idle, 0, 1) {
+	if !atomic.CompareAndSwapInt32(&p.blockIdle, 0, 1) {
 		return errAlreadyFetching
 	}
-	p.started = time.Now()
+	p.blockStarted = time.Now()
 
 	// Convert the header set to a retrievable slice
 	hashes := make([]common.Hash, 0, len(request.Headers))
@@ -137,55 +149,64 @@ func (p *peer) Fetch(request *fetchRequest) error {
 	return nil
 }
 
-// SetIdle61 sets the peer to idle, allowing it to execute new retrieval requests.
+// FetchReceipts sends a receipt retrieval request to the remote peer.
+func (p *peer) FetchReceipts(request *fetchRequest) error {
+	// Short circuit if the peer is already fetching
+	if !atomic.CompareAndSwapInt32(&p.receiptIdle, 0, 1) {
+		return errAlreadyFetching
+	}
+	p.receiptStarted = time.Now()
+
+	// Convert the header set to a retrievable slice
+	hashes := make([]common.Hash, 0, len(request.Headers))
+	for _, header := range request.Headers {
+		hashes = append(hashes, header.Hash())
+	}
+	go p.getReceipts(hashes)
+
+	return nil
+}
+
+// SetBlocksIdle sets the peer to idle, allowing it to execute new retrieval requests.
 // Its block retrieval allowance will also be updated either up- or downwards,
 // depending on whether the previous fetch completed in time or not.
-func (p *peer) SetIdle61() {
+func (p *peer) SetBlocksIdle() {
-	// Update the peer's download allowance based on previous performance
+	p.setIdle(p.blockStarted, blockSoftTTL, blockHardTTL, MaxBlockFetch, &p.blockCapacity, &p.blockIdle)
-	scale := 2.0
-	if time.Since(p.started) > blockSoftTTL {
-		scale = 0.5
-		if time.Since(p.started) > blockHardTTL {
-			scale = 1 / float64(MaxBlockFetch) // reduces capacity to 1
-		}
-	}
-	for {
-		// Calculate the new download bandwidth allowance
-		prev := atomic.LoadInt32(&p.capacity)
-		next := int32(math.Max(1, math.Min(float64(MaxBlockFetch), float64(prev)*scale)))
-
-		// Try to update the old value
-		if atomic.CompareAndSwapInt32(&p.capacity, prev, next) {
-			// If we're having problems at 1 capacity, try to find better peers
-			if next == 1 {
-				p.Demote()
-			}
-			break
-		}
-	}
-	// Set the peer to idle to allow further block requests
-	atomic.StoreInt32(&p.idle, 0)
 }
 
-// SetIdle sets the peer to idle, allowing it to execute new retrieval requests.
+// SetBodiesIdle sets the peer to idle, allowing it to execute new retrieval requests.
 // Its block body retrieval allowance will also be updated either up- or downwards,
 // depending on whether the previous fetch completed in time or not.
-func (p *peer) SetIdle() {
+func (p *peer) SetBodiesIdle() {
+	p.setIdle(p.blockStarted, bodySoftTTL, bodyHardTTL, MaxBlockFetch, &p.blockCapacity, &p.blockIdle)
+}
+
+// SetReceiptsIdle sets the peer to idle, allowing it to execute new retrieval requests.
+// Its receipt retrieval allowance will also be updated either up- or downwards,
+// depending on whether the previous fetch completed in time or not.
+func (p *peer) SetReceiptsIdle() {
+	p.setIdle(p.receiptStarted, receiptSoftTTL, receiptHardTTL, MaxReceiptFetch, &p.receiptCapacity, &p.receiptIdle)
+}
+
+// setIdle sets the peer to idle, allowing it to execute new retrieval requests.
+// Its data retrieval allowance will also be updated either up- or downwards,
+// depending on whether the previous fetch completed in time or not.
+func (p *peer) setIdle(started time.Time, softTTL, hardTTL time.Duration, maxFetch int, capacity, idle *int32) {
 	// Update the peer's download allowance based on previous performance
 	scale := 2.0
-	if time.Since(p.started) > bodySoftTTL {
+	if time.Since(started) > softTTL {
 		scale = 0.5
-		if time.Since(p.started) > bodyHardTTL {
+		if time.Since(started) > hardTTL {
-			scale = 1 / float64(MaxBodyFetch) // reduces capacity to 1
+			scale = 1 / float64(maxFetch) // reduces capacity to 1
 		}
 	}
 	for {
 		// Calculate the new download bandwidth allowance
-		prev := atomic.LoadInt32(&p.capacity)
+		prev := atomic.LoadInt32(capacity)
-		next := int32(math.Max(1, math.Min(float64(MaxBodyFetch), float64(prev)*scale)))
+		next := int32(math.Max(1, math.Min(float64(maxFetch), float64(prev)*scale)))
 
 		// Try to update the old value
-		if atomic.CompareAndSwapInt32(&p.capacity, prev, next) {
+		if atomic.CompareAndSwapInt32(capacity, prev, next) {
 			// If we're having problems at 1 capacity, try to find better peers
 			if next == 1 {
 				p.Demote()
@@ -193,14 +214,20 @@ func (p *peer) SetIdle() {
 			break
 		}
 	}
-	// Set the peer to idle to allow further block requests
+	// Set the peer to idle to allow further fetch requests
-	atomic.StoreInt32(&p.idle, 0)
+	atomic.StoreInt32(idle, 0)
 }
 
-// Capacity retrieves the peers block download allowance based on its previously
+// BlockCapacity retrieves the peers block download allowance based on its
-// discovered bandwidth capacity.
+// previously discovered bandwidth capacity.
-func (p *peer) Capacity() int {
+func (p *peer) BlockCapacity() int {
-	return int(atomic.LoadInt32(&p.capacity))
+	return int(atomic.LoadInt32(&p.blockCapacity))
+}
+
+// ReceiptCapacity retrieves the peers block download allowance based on its
+// previously discovered bandwidth capacity.
+func (p *peer) ReceiptCapacity() int {
+	return int(atomic.LoadInt32(&p.receiptCapacity))
 }
 
 // Promote increases the peer's reputation.
@@ -226,7 +253,8 @@ func (p *peer) Demote() {
 func (p *peer) String() string {
 	return fmt.Sprintf("Peer %s [%s]", p.id,
 		fmt.Sprintf("reputation %3d, ", atomic.LoadInt32(&p.rep))+
-			fmt.Sprintf("capacity %3d, ", atomic.LoadInt32(&p.capacity))+
+			fmt.Sprintf("block cap %3d, ", atomic.LoadInt32(&p.blockCapacity))+
+			fmt.Sprintf("receipt cap %3d, ", atomic.LoadInt32(&p.receiptCapacity))+
 			fmt.Sprintf("ignored %4d", p.ignored.Size()),
 	)
 }
@@ -310,26 +338,52 @@ func (ps *peerSet) AllPeers() []*peer {
 	return list
 }
 
-// IdlePeers retrieves a flat list of all the currently idle peers within the
+// BlockIdlePeers retrieves a flat list of all the currently idle peers within the
 // active peer set, ordered by their reputation.
-func (ps *peerSet) IdlePeers(version int) []*peer {
+func (ps *peerSet) BlockIdlePeers(version int) ([]*peer, int) {
 	ps.lock.RLock()
 	defer ps.lock.RUnlock()
 
-	list := make([]*peer, 0, len(ps.peers))
+	idle, total := make([]*peer, 0, len(ps.peers)), 0
 	for _, p := range ps.peers {
-		if (version == eth61 && p.version == eth61) || (version >= eth62 && p.version >= eth62) {
+		if (version == 61 && p.version == 61) || (version >= 62 && p.version >= 62) {
-			if atomic.LoadInt32(&p.idle) == 0 {
+			if atomic.LoadInt32(&p.blockIdle) == 0 {
-				list = append(list, p)
+				idle = append(idle, p)
+			}
+			total++
+		}
+	}
+	for i := 0; i < len(idle); i++ {
+		for j := i + 1; j < len(idle); j++ {
+			if atomic.LoadInt32(&idle[i].rep) < atomic.LoadInt32(&idle[j].rep) {
+				idle[i], idle[j] = idle[j], idle[i]
 			}
 		}
 	}
-	for i := 0; i < len(list); i++ {
+	return idle, total
-		for j := i + 1; j < len(list); j++ {
+}
-			if atomic.LoadInt32(&list[i].rep) < atomic.LoadInt32(&list[j].rep) {
+
-				list[i], list[j] = list[j], list[i]
+// ReceiptIdlePeers retrieves a flat list of all the currently idle peers within the
-			}
+// active peer set, ordered by their reputation.
-		}
+func (ps *peerSet) ReceiptIdlePeers() ([]*peer, int) {
-	}
+	ps.lock.RLock()
-	return list
+	defer ps.lock.RUnlock()
+
+	idle, total := make([]*peer, 0, len(ps.peers)), 0
+	for _, p := range ps.peers {
+		if p.version >= 63 {
+			if atomic.LoadInt32(&p.receiptIdle) == 0 {
+				idle = append(idle, p)
+			}
+			total++
+		}
+	}
+	for i := 0; i < len(idle); i++ {
+		for j := i + 1; j < len(idle); j++ {
+			if atomic.LoadInt32(&idle[i].rep) < atomic.LoadInt32(&idle[j].rep) {
+				idle[i], idle[j] = idle[j], idle[i]
+			}
+		}
+	}
+	return idle, total
 }

eth/downloader/queue.go

@@ -29,11 +29,12 @@ import (
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/logger"
 	"github.com/ethereum/go-ethereum/logger/glog"
+	"github.com/rcrowley/go-metrics"
 	"gopkg.in/karalabe/cookiejar.v2/collections/prque"
 )
 
 var (
-	blockCacheLimit = 8 * MaxBlockFetch // Maximum number of blocks to cache before throttling the download
+	blockCacheLimit = 1024 // Maximum number of blocks to cache before throttling the download
 )
 
 var (
@@ -41,29 +42,47 @@ var (
 	errStaleDelivery    = errors.New("stale delivery")
 )
 
-// fetchRequest is a currently running block retrieval operation.
+// fetchRequest is a currently running data retrieval operation.
 type fetchRequest struct {
 	Peer    *peer               // Peer to which the request was sent
-	Hashes  map[common.Hash]int // [eth/61] Requested hashes with their insertion index (priority)
+	Hashes  map[common.Hash]int // [eth/61] Requested block with their insertion index (priority)
 	Headers []*types.Header     // [eth/62] Requested headers, sorted by request order
 	Time    time.Time           // Time when the request was made
 }
 
+// fetchResult is the assembly collecting partial results from potentially more
+// than one fetcher routines, until all outstanding retrievals complete and the
+// result as a whole can be processed.
+type fetchResult struct {
+	Pending int // Number of data fetches still pending
+
+	Header       *types.Header
+	Uncles       []*types.Header
+	Transactions types.Transactions
+	Receipts     types.Receipts
+}
+
 // queue represents hashes that are either need fetching or are being fetched
 type queue struct {
 	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
 
-	headerPool  map[common.Hash]*types.Header // [eth/62] Pending headers, mapping from their hashes
-	headerQueue *prque.Prque                  // [eth/62] Priority queue of the headers to fetch the bodies for
 	headerHead common.Hash // [eth/62] Hash of the last queued header to verify order
 
-	pendPool map[string]*fetchRequest // Currently pending block retrieval operations
+	blockTaskPool  map[common.Hash]*types.Header // [eth/62] Pending block (body) retrieval tasks, mapping hashes to headers
+	blockTaskQueue *prque.Prque                  // [eth/62] Priority queue of the headers to fetch the blocks (bodies) for
+	blockPendPool  map[string]*fetchRequest      // [eth/62] Currently pending block (body) retrieval operations
+	blockDonePool  map[common.Hash]struct{}      // [eth/62] Set of the completed block (body) fetches
 
-	blockPool   map[common.Hash]uint64 // Hash-set of the downloaded data blocks, mapping to cache indexes
+	receiptTaskPool  map[common.Hash]*types.Header // [eth/63] Pending receipt retrieval tasks, mapping hashes to headers
-	blockCache  []*Block               // Downloaded but not yet delivered blocks
+	receiptTaskQueue *prque.Prque                  // [eth/63] Priority queue of the headers to fetch the receipts for
-	blockOffset uint64                 // Offset of the first cached block in the block-chain
+	receiptPendPool  map[string]*fetchRequest      // [eth/63] Currently pending receipt retrieval operations
+	receiptDonePool  map[common.Hash]struct{}      // [eth/63] Set of the completed receipt fetches
+
+	resultCache  []*fetchResult // Downloaded but not yet delivered fetch results
+	resultOffset uint64         // Offset of the first cached fetch result in the block-chain
+	resultParts  int            // Number of fetch components required to complete an item
 
 	lock sync.RWMutex
 }
@@ -73,11 +92,15 @@ func newQueue() *queue {
 	return &queue{
 		hashPool:         make(map[common.Hash]int),
 		hashQueue:        prque.New(),
-		headerPool:  make(map[common.Hash]*types.Header),
+		blockTaskPool:    make(map[common.Hash]*types.Header),
-		headerQueue: prque.New(),
+		blockTaskQueue:   prque.New(),
-		pendPool:    make(map[string]*fetchRequest),
+		blockPendPool:    make(map[string]*fetchRequest),
-		blockPool:   make(map[common.Hash]uint64),
+		blockDonePool:    make(map[common.Hash]struct{}),
-		blockCache:  make([]*Block, blockCacheLimit),
+		receiptTaskPool:  make(map[common.Hash]*types.Header),
+		receiptTaskQueue: prque.New(),
+		receiptPendPool:  make(map[string]*fetchRequest),
+		receiptDonePool:  make(map[common.Hash]struct{}),
+		resultCache:      make([]*fetchResult, blockCacheLimit),
 	}
 }
 
@@ -90,32 +113,37 @@ func (q *queue) Reset() {
 	q.hashQueue.Reset()
 	q.hashCounter = 0
 
-	q.headerPool = make(map[common.Hash]*types.Header)
-	q.headerQueue.Reset()
 	q.headerHead = common.Hash{}
 
-	q.pendPool = make(map[string]*fetchRequest)
+	q.blockTaskPool = make(map[common.Hash]*types.Header)
+	q.blockTaskQueue.Reset()
+	q.blockPendPool = make(map[string]*fetchRequest)
+	q.blockDonePool = make(map[common.Hash]struct{})
 
-	q.blockPool = make(map[common.Hash]uint64)
+	q.receiptTaskPool = make(map[common.Hash]*types.Header)
-	q.blockOffset = 0
+	q.receiptTaskQueue.Reset()
-	q.blockCache = make([]*Block, blockCacheLimit)
+	q.receiptPendPool = make(map[string]*fetchRequest)
+	q.receiptDonePool = make(map[common.Hash]struct{})
+
+	q.resultCache = make([]*fetchResult, blockCacheLimit)
+	q.resultOffset = 0
+	q.resultParts = 0
 }
 
-// Size retrieves the number of blocks in the queue, returning separately for
+// PendingBlocks retrieves the number of block (body) requests pending for retrieval.
-// pending and already downloaded.
+func (q *queue) PendingBlocks() int {
-func (q *queue) Size() (int, int) {
 	q.lock.RLock()
 	defer q.lock.RUnlock()
 
-	return len(q.hashPool) + len(q.headerPool), len(q.blockPool)
+	return q.hashQueue.Size() + q.blockTaskQueue.Size()
 }
 
-// Pending retrieves the number of blocks pending for retrieval.
+// PendingReceipts retrieves the number of block receipts pending for retrieval.
-func (q *queue) Pending() int {
+func (q *queue) PendingReceipts() int {
 	q.lock.RLock()
 	defer q.lock.RUnlock()
 
-	return q.hashQueue.Size() + q.headerQueue.Size()
+	return q.receiptTaskQueue.Size()
 }
 
 // InFlight retrieves the number of fetch requests currently in flight.
@@ -123,44 +151,55 @@ func (q *queue) InFlight() int {
 	q.lock.RLock()
 	defer q.lock.RUnlock()
 
-	return len(q.pendPool)
+	return len(q.blockPendPool) + len(q.receiptPendPool)
 }
 
-// Throttle checks if the download should be throttled (active block fetches
+// Idle returns if the queue is fully idle or has some data still inside. This
-// exceed block cache).
+// method is used by the tester to detect termination events.
-func (q *queue) Throttle() bool {
+func (q *queue) Idle() bool {
 	q.lock.RLock()
 	defer q.lock.RUnlock()
 
-	// Calculate the currently in-flight block requests
+	queued := q.hashQueue.Size() + q.blockTaskQueue.Size() + q.receiptTaskQueue.Size()
+	pending := len(q.blockPendPool) + len(q.receiptPendPool)
+	cached := len(q.blockDonePool) + len(q.receiptDonePool)
+
+	return (queued + pending + cached) == 0
+}
+
+// ThrottleBlocks checks if the download should be throttled (active block (body)
+// fetches exceed block cache).
+func (q *queue) ThrottleBlocks() bool {
+	q.lock.RLock()
+	defer q.lock.RUnlock()
+
+	// Calculate the currently in-flight block (body) requests
 	pending := 0
-	for _, request := range q.pendPool {
+	for _, request := range q.blockPendPool {
 		pending += len(request.Hashes) + len(request.Headers)
 	}
-	// Throttle if more blocks are in-flight than free space in the cache
+	// Throttle if more blocks (bodies) are in-flight than free space in the cache
-	return pending >= len(q.blockCache)-len(q.blockPool)
+	return pending >= len(q.resultCache)-len(q.blockDonePool)
 }
 
-// Has checks if a hash is within the download queue or not.
+// ThrottleReceipts checks if the download should be throttled (active receipt
-func (q *queue) Has(hash common.Hash) bool {
+// fetches exceed block cache).
+func (q *queue) ThrottleReceipts() bool {
 	q.lock.RLock()
 	defer q.lock.RUnlock()
 
-	if _, ok := q.hashPool[hash]; ok {
+	// Calculate the currently in-flight receipt requests
-		return true
+	pending := 0
+	for _, request := range q.receiptPendPool {
+		pending += len(request.Headers)
 	}
-	if _, ok := q.headerPool[hash]; ok {
+	// Throttle if more receipts are in-flight than free space in the cache
-		return true
+	return pending >= len(q.resultCache)-len(q.receiptDonePool)
-	}
-	if _, ok := q.blockPool[hash]; ok {
-		return true
-	}
-	return false
 }
 
-// Insert61 adds a set of hashes for the download queue for scheduling, returning
+// Schedule61 adds a set of hashes for the download queue for scheduling, returning
 // the new hashes encountered.
-func (q *queue) Insert61(hashes []common.Hash, fifo bool) []common.Hash {
+func (q *queue) Schedule61(hashes []common.Hash, fifo bool) []common.Hash {
 	q.lock.Lock()
 	defer q.lock.Unlock()
 
@@ -186,22 +225,17 @@ func (q *queue) Insert61(hashes []common.Hash, fifo bool) []common.Hash {
 	return inserts
 }
 
-// Insert adds a set of headers for the download queue for scheduling, returning
+// Schedule adds a set of headers for the download queue for scheduling, returning
 // the new headers encountered.
-func (q *queue) Insert(headers []*types.Header, from uint64) []*types.Header {
+func (q *queue) Schedule(headers []*types.Header, from uint64, receipts bool) []*types.Header {
 	q.lock.Lock()
 	defer q.lock.Unlock()
 
 	// Insert all the headers prioritized by the contained block number
 	inserts := make([]*types.Header, 0, len(headers))
 	for _, header := range headers {
-		// Make sure no duplicate requests are executed
-		hash := header.Hash()
-		if _, ok := q.headerPool[hash]; ok {
-			glog.V(logger.Warn).Infof("Header #%d [%x] already scheduled", header.Number.Uint64(), hash[:4])
-			continue
-		}
 		// Make sure chain order is honored and preserved throughout
+		hash := header.Hash()
 		if header.Number == nil || header.Number.Uint64() != from {
 			glog.V(logger.Warn).Infof("Header #%v [%x] broke chain ordering, expected %d", header.Number, hash[:4], from)
 			break
@@ -210,69 +244,72 @@ func (q *queue) Insert(headers []*types.Header, from uint64) []*types.Header {
 			glog.V(logger.Warn).Infof("Header #%v [%x] broke chain ancestry", header.Number, hash[:4])
 			break
 		}
-		// Queue the header for body retrieval
+		// Make sure no duplicate requests are executed
+		if _, ok := q.blockTaskPool[hash]; ok {
+			glog.V(logger.Warn).Infof("Header #%d [%x] already scheduled for block fetch", header.Number.Uint64(), hash[:4])
+			continue
+		}
+		if _, ok := q.receiptTaskPool[hash]; ok {
+			glog.V(logger.Warn).Infof("Header #%d [%x] already scheduled for receipt fetch", header.Number.Uint64(), hash[:4])
+			continue
+		}
+		// Queue the header for content retrieval
+		q.blockTaskPool[hash] = header
+		q.blockTaskQueue.Push(header, -float32(header.Number.Uint64()))
+		if receipts {
+			q.receiptTaskPool[hash] = header
+			q.receiptTaskQueue.Push(header, -float32(header.Number.Uint64()))
+		}
 		inserts = append(inserts, header)
-		q.headerPool[hash] = header
-		q.headerQueue.Push(header, -float32(header.Number.Uint64()))
 		q.headerHead = hash
 		from++
 	}
 	return inserts
 }
 
-// GetHeadBlock retrieves the first block from the cache, or nil if it hasn't
+// GetHeadResult retrieves the first fetch result from the cache, or nil if it hasn't
 // been downloaded yet (or simply non existent).
-func (q *queue) GetHeadBlock() *Block {
+func (q *queue) GetHeadResult() *fetchResult {
 	q.lock.RLock()
 	defer q.lock.RUnlock()
 
-	if len(q.blockCache) == 0 {
+	if len(q.resultCache) == 0 || q.resultCache[0] == nil {
 		return nil
 	}
-	return q.blockCache[0]
+	if q.resultCache[0].Pending > 0 {
+		return nil
+	}
+	return q.resultCache[0]
 }
 
-// GetBlock retrieves a downloaded block, or nil if non-existent.
+// TakeResults retrieves and permanently removes a batch of fetch results from
-func (q *queue) GetBlock(hash common.Hash) *Block {
+// the cache.
-	q.lock.RLock()
+func (q *queue) TakeResults() []*fetchResult {
-	defer q.lock.RUnlock()
-
-	// Short circuit if the block hasn't been downloaded yet
-	index, ok := q.blockPool[hash]
-	if !ok {
-		return nil
-	}
-	// Return the block if it's still available in the cache
-	if q.blockOffset <= index && index < q.blockOffset+uint64(len(q.blockCache)) {
-		return q.blockCache[index-q.blockOffset]
-	}
-	return nil
-}
-
-// TakeBlocks retrieves and permanently removes a batch of blocks from the cache.
-func (q *queue) TakeBlocks() []*Block {
 	q.lock.Lock()
 	defer q.lock.Unlock()
 
-	// Accumulate all available blocks
+	// Accumulate all available results
-	blocks := []*Block{}
+	results := []*fetchResult{}
-	for _, block := range q.blockCache {
+	for _, result := range q.resultCache {
-		if block == nil {
+		if result == nil || result.Pending > 0 {
 			break
 		}
-		blocks = append(blocks, block)
+		results = append(results, result)
-		delete(q.blockPool, block.RawBlock.Hash())
-	}
-	// Delete the blocks from the slice and let them be garbage collected
-	// without this slice trick the blocks would stay in memory until nil
-	// would be assigned to q.blocks
-	copy(q.blockCache, q.blockCache[len(blocks):])
-	for k, n := len(q.blockCache)-len(blocks), len(q.blockCache); k < n; k++ {
-		q.blockCache[k] = nil
-	}
-	q.blockOffset += uint64(len(blocks))
 
-	return blocks
+		hash := result.Header.Hash()
+		delete(q.blockDonePool, hash)
+		delete(q.receiptDonePool, hash)
+	}
+	// Delete the results from the slice and let them be garbage collected
+	// without this slice trick the results would stay in memory until nil
+	// would be assigned to them.
+	copy(q.resultCache, q.resultCache[len(results):])
+	for k, n := len(q.resultCache)-len(results), len(q.resultCache); k < n; k++ {
+		q.resultCache[k] = nil
+	}
+	q.resultOffset += uint64(len(results))
+
+	return results
 }
 
 // Reserve61 reserves a set of hashes for the given peer, skipping any previously
@@ -286,12 +323,12 @@ func (q *queue) Reserve61(p *peer, count int) *fetchRequest {
 	if q.hashQueue.Empty() {
 		return nil
 	}
-	if _, ok := q.pendPool[p.id]; ok {
+	if _, ok := q.blockPendPool[p.id]; ok {
 		return nil
 	}
 	// Calculate an upper limit on the hashes we might fetch (i.e. throttling)
-	space := len(q.blockCache) - len(q.blockPool)
+	space := len(q.resultCache) - len(q.blockDonePool)
-	for _, request := range q.pendPool {
+	for _, request := range q.blockPendPool {
 		space -= len(request.Hashes)
 	}
 	// Retrieve a batch of hashes, skipping previously failed ones
@@ -319,49 +356,82 @@ func (q *queue) Reserve61(p *peer, count int) *fetchRequest {
 		Hashes: send,
 		Time:   time.Now(),
 	}
-	q.pendPool[p.id] = request
+	q.blockPendPool[p.id] = request
 
 	return request
 }
 
-// Reserve reserves a set of headers for the given peer, skipping any previously
+// ReserveBlocks reserves a set of body fetches for the given peer, skipping any
-// failed download. Beside the next batch of needed fetches, it also returns a
+// previously failed downloads. Beside the next batch of needed fetches, it also
-// flag whether empty blocks were queued requiring processing.
+// returns a flag whether empty blocks were queued requiring processing.
-func (q *queue) Reserve(p *peer, count int) (*fetchRequest, bool, error) {
+func (q *queue) ReserveBlocks(p *peer, count int) (*fetchRequest, bool, error) {
+	noop := func(header *types.Header) bool {
+		return header.TxHash == types.EmptyRootHash && header.UncleHash == types.EmptyUncleHash
+	}
+	return q.reserveFetch(p, count, q.blockTaskPool, q.blockTaskQueue, q.blockPendPool, q.blockDonePool, noop)
+}
+
+// ReserveReceipts reserves a set of receipt fetches for the given peer, skipping
+// any previously failed downloads. Beside the next batch of needed fetches, it
+// also returns a flag whether empty receipts were queued requiring importing.
+func (q *queue) ReserveReceipts(p *peer, count int) (*fetchRequest, bool, error) {
+	noop := func(header *types.Header) bool {
+		return header.ReceiptHash == types.EmptyRootHash
+	}
+	return q.reserveFetch(p, count, q.receiptTaskPool, q.receiptTaskQueue, q.receiptPendPool, q.receiptDonePool, noop)
+}
+
+// reserveFetch reserves a set of data download operations for a given peer,
+// skipping any previously failed ones. This method is a generic version used
+// by the individual special reservation functions.
+func (q *queue) reserveFetch(p *peer, count int, taskPool map[common.Hash]*types.Header, taskQueue *prque.Prque,
+	pendPool map[string]*fetchRequest, donePool map[common.Hash]struct{}, noop func(*types.Header) bool) (*fetchRequest, bool, error) {
 	q.lock.Lock()
 	defer q.lock.Unlock()
 
 	// Short circuit if the pool has been depleted, or if the peer's already
 	// downloading something (sanity check not to corrupt state)
-	if q.headerQueue.Empty() {
+	if taskQueue.Empty() {
 		return nil, false, nil
 	}
-	if _, ok := q.pendPool[p.id]; ok {
+	if _, ok := pendPool[p.id]; ok {
 		return nil, false, nil
 	}
-	// Calculate an upper limit on the bodies we might fetch (i.e. throttling)
+	// Calculate an upper limit on the items we might fetch (i.e. throttling)
-	space := len(q.blockCache) - len(q.blockPool)
+	space := len(q.resultCache) - len(donePool)
-	for _, request := range q.pendPool {
+	for _, request := range pendPool {
 		space -= len(request.Headers)
 	}
-	// Retrieve a batch of headers, skipping previously failed ones
+	// Retrieve a batch of tasks, skipping previously failed ones
 	send := make([]*types.Header, 0, count)
 	skip := make([]*types.Header, 0)
 
-	process := false
+	progress := false
-	for proc := 0; proc < space && len(send) < count && !q.headerQueue.Empty(); proc++ {
+	for proc := 0; proc < space && len(send) < count && !taskQueue.Empty(); proc++ {
-		header := q.headerQueue.PopItem().(*types.Header)
+		header := taskQueue.PopItem().(*types.Header)
 
-		// If the header defines an empty block, deliver straight
+		// If we're the first to request this task, initialize the result container
-		if header.TxHash == types.DeriveSha(types.Transactions{}) && header.UncleHash == types.CalcUncleHash([]*types.Header{}) {
+		index := int(header.Number.Int64() - int64(q.resultOffset))
-			if err := q.enqueue("", types.NewBlockWithHeader(header)); err != nil {
+		if index >= len(q.resultCache) || index < 0 {
 			return nil, false, errInvalidChain
 		}
-			delete(q.headerPool, header.Hash())
+		if q.resultCache[index] == nil {
-			process, space, proc = true, space-1, proc-1
+			q.resultCache[index] = &fetchResult{
+				Pending: q.resultParts,
+				Header:  header,
+			}
+		}
+		// If this fetch task is a noop, skip this fetch operation
+		if noop(header) {
+			donePool[header.Hash()] = struct{}{}
+			delete(taskPool, header.Hash())
+
+			space, proc = space-1, proc-1
+			q.resultCache[index].Pending--
+			progress = true
 			continue
 		}
-		// If it's a content block, add to the body fetch request
+		// Otherwise if not a known unknown block, add to the retrieve list
 		if p.ignored.Has(header.Hash()) {
 			skip = append(skip, header)
 		} else {
@@ -370,24 +440,41 @@ func (q *queue) Reserve(p *peer, count int) (*fetchRequest, bool, error) {
 	}
 	// Merge all the skipped headers back
 	for _, header := range skip {
-		q.headerQueue.Push(header, -float32(header.Number.Uint64()))
+		taskQueue.Push(header, -float32(header.Number.Uint64()))
 	}
 	// Assemble and return the block download request
 	if len(send) == 0 {
-		return nil, process, nil
+		return nil, progress, nil
 	}
 	request := &fetchRequest{
 		Peer:    p,
 		Headers: send,
 		Time:    time.Now(),
 	}
-	q.pendPool[p.id] = request
+	pendPool[p.id] = request
 
-	return request, process, nil
+	return request, progress, nil
 }
 
-// Cancel aborts a fetch request, returning all pending hashes to the queue.
+// Cancel61 aborts a fetch request, returning all pending hashes to the queue.
-func (q *queue) Cancel(request *fetchRequest) {
+func (q *queue) Cancel61(request *fetchRequest) {
+	q.cancel(request, nil, q.blockPendPool)
+}
+
+// CancelBlocks aborts a body fetch request, returning all pending hashes to the
+// task queue.
+func (q *queue) CancelBlocks(request *fetchRequest) {
+	q.cancel(request, q.blockTaskQueue, q.blockPendPool)
+}
+
+// CancelReceipts aborts a body fetch request, returning all pending hashes to
+// the task queue.
+func (q *queue) CancelReceipts(request *fetchRequest) {
+	q.cancel(request, q.receiptTaskQueue, q.receiptPendPool)
+}
+
+// Cancel aborts a fetch request, returning all pending hashes to the task queue.
+func (q *queue) cancel(request *fetchRequest, taskQueue *prque.Prque, pendPool map[string]*fetchRequest) {
 	q.lock.Lock()
 	defer q.lock.Unlock()
 
@@ -395,20 +482,62 @@ func (q *queue) Cancel(request *fetchRequest) {
 		q.hashQueue.Push(hash, float32(index))
 	}
 	for _, header := range request.Headers {
-		q.headerQueue.Push(header, -float32(header.Number.Uint64()))
+		taskQueue.Push(header, -float32(header.Number.Uint64()))
 	}
-	delete(q.pendPool, request.Peer.id)
+	delete(pendPool, request.Peer.id)
 }
 
-// Expire checks for in flight requests that exceeded a timeout allowance,
+// Revoke cancels all pending requests belonging to a given peer. This method is
+// meant to be called during a peer drop to quickly reassign owned data fetches
+// to remaining nodes.
+func (q *queue) Revoke(peerId string) {
+	q.lock.Lock()
+	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()))
+		}
+		delete(q.blockPendPool, peerId)
+	}
+	if request, ok := q.receiptPendPool[peerId]; ok {
+		for _, header := range request.Headers {
+			q.receiptTaskQueue.Push(header, -float32(header.Number.Uint64()))
+		}
+		delete(q.receiptPendPool, peerId)
+	}
+}
+
+// Expire61 checks for in flight requests that exceeded a timeout allowance,
 // canceling them and returning the responsible peers for penalization.
-func (q *queue) Expire(timeout time.Duration) []string {
+func (q *queue) Expire61(timeout time.Duration) []string {
+	return q.expire(timeout, q.blockPendPool, nil)
+}
+
+// ExpireBlocks checks for in flight block body requests that exceeded a timeout
+// allowance, canceling them and returning the responsible peers for penalization.
+func (q *queue) ExpireBlocks(timeout time.Duration) []string {
+	return q.expire(timeout, q.blockPendPool, q.blockTaskQueue)
+}
+
+// ExpireReceipts checks for in flight receipt requests that exceeded a timeout
+// allowance, canceling them and returning the responsible peers for penalization.
+func (q *queue) ExpireReceipts(timeout time.Duration) []string {
+	return q.expire(timeout, q.receiptPendPool, q.receiptTaskQueue)
+}
+
+// expire is the generic check that move expired tasks from a pending pool back
+// into a task pool, returning all entities caught with expired tasks.
+func (q *queue) expire(timeout time.Duration, pendPool map[string]*fetchRequest, taskQueue *prque.Prque) []string {
 	q.lock.Lock()
 	defer q.lock.Unlock()
 
 	// Iterate over the expired requests and return each to the queue
 	peers := []string{}
-	for id, request := range q.pendPool {
+	for id, request := range pendPool {
 		if time.Since(request.Time) > timeout {
 			// Update the metrics with the timeout
 			if len(request.Hashes) > 0 {
@@ -421,14 +550,14 @@ func (q *queue) Expire(timeout time.Duration) []string {
 				q.hashQueue.Push(hash, float32(index))
 			}
 			for _, header := range request.Headers {
-				q.headerQueue.Push(header, -float32(header.Number.Uint64()))
+				taskQueue.Push(header, -float32(header.Number.Uint64()))
 			}
 			peers = append(peers, id)
 		}
 	}
 	// Remove the expired requests from the pending pool
 	for _, id := range peers {
-		delete(q.pendPool, id)
+		delete(pendPool, id)
 	}
 	return peers
 }
@@ -439,12 +568,12 @@ func (q *queue) Deliver61(id string, blocks []*types.Block) (err error) {
 	defer q.lock.Unlock()
 
 	// Short circuit if the blocks were never requested
-	request := q.pendPool[id]
+	request := q.blockPendPool[id]
 	if request == nil {
 		return errNoFetchesPending
 	}
 	blockReqTimer.UpdateSince(request.Time)
-	delete(q.pendPool, id)
+	delete(q.blockPendPool, id)
 
 	// If no blocks were retrieved, mark them as unavailable for the origin peer
 	if len(blocks) == 0 {
@@ -461,10 +590,19 @@ func (q *queue) Deliver61(id string, blocks []*types.Block) (err error) {
 			errs = append(errs, fmt.Errorf("non-requested block %x", hash))
 			continue
 		}
-		// Queue the block up for processing
+		// Reconstruct the next result if contents match up
-		if err := q.enqueue(id, block); err != nil {
+		index := int(block.Number().Int64() - int64(q.resultOffset))
-			return err
+		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)
 	}
@@ -473,72 +611,12 @@ func (q *queue) Deliver61(id string, blocks []*types.Block) (err error) {
 		q.hashQueue.Push(hash, float32(index))
 	}
 	// If none of the blocks were good, it's a stale delivery
-	if len(errs) != 0 {
-		if len(errs) == len(blocks) {
-			return errStaleDelivery
-		}
-		return fmt.Errorf("multiple failures: %v", errs)
-	}
-	return nil
-}
-
-// Deliver injects a block body retrieval response into the download queue.
-func (q *queue) Deliver(id string, txLists [][]*types.Transaction, uncleLists [][]*types.Header) error {
-	q.lock.Lock()
-	defer q.lock.Unlock()
-
-	// Short circuit if the block bodies were never requested
-	request := q.pendPool[id]
-	if request == nil {
-		return errNoFetchesPending
-	}
-	bodyReqTimer.UpdateSince(request.Time)
-	delete(q.pendPool, id)
-
-	// If no block bodies were retrieved, mark them as unavailable for the origin peer
-	if len(txLists) == 0 || len(uncleLists) == 0 {
-		for hash, _ := range request.Headers {
-			request.Peer.ignored.Add(hash)
-		}
-	}
-	// Assemble each of the block bodies with their headers and queue for processing
-	errs := make([]error, 0)
-	for i, header := range request.Headers {
-		// Short circuit block assembly if no more bodies are found
-		if i >= len(txLists) || i >= len(uncleLists) {
-			break
-		}
-		// Reconstruct the next block if contents match up
-		if types.DeriveSha(types.Transactions(txLists[i])) != header.TxHash || types.CalcUncleHash(uncleLists[i]) != header.UncleHash {
-			errs = []error{errInvalidBody}
-			break
-		}
-		block := types.NewBlockWithHeader(header).WithBody(txLists[i], uncleLists[i])
-
-		// Queue the block up for processing
-		if err := q.enqueue(id, block); err != nil {
-			errs = []error{err}
-			break
-		}
-		request.Headers[i] = nil
-		delete(q.headerPool, header.Hash())
-	}
-	// Return all failed or missing fetches to the queue
-	for _, header := range request.Headers {
-		if header != nil {
-			q.headerQueue.Push(header, -float32(header.Number.Uint64()))
-		}
-	}
-	// If none of the blocks were good, it's a stale delivery
 	switch {
 	case len(errs) == 0:
 		return nil
 
-	case len(errs) == 1 && errs[0] == errInvalidBody:
+	case len(errs) == 1 && (errs[0] == errInvalidChain || errs[0] == errInvalidBlock):
-		return errInvalidBody
+		return errs[0]
-
-	case len(errs) == 1 && errs[0] == errInvalidChain:
-		return errInvalidChain
 
 	case len(errs) == len(request.Headers):
 		return errStaleDelivery
@@ -548,29 +626,105 @@ func (q *queue) Deliver(id string, txLists [][]*types.Transaction, uncleLists []
 	}
 }
 
-// enqueue inserts a new block into the final delivery queue, waiting for pickup
+// DeliverBlocks injects a block (body) retrieval response into the results queue.
-// by the processor.
+func (q *queue) DeliverBlocks(id string, txLists [][]*types.Transaction, uncleLists [][]*types.Header) error {
-func (q *queue) enqueue(origin string, block *types.Block) error {
+	reconstruct := func(header *types.Header, index int, result *fetchResult) error {
-	// If a requested block falls out of the range, the hash chain is invalid
+		if types.DeriveSha(types.Transactions(txLists[index])) != header.TxHash || types.CalcUncleHash(uncleLists[index]) != header.UncleHash {
-	index := int(int64(block.NumberU64()) - int64(q.blockOffset))
+			return errInvalidBody
-	if index >= len(q.blockCache) || index < 0 {
-		return errInvalidChain
 		}
-	// Otherwise merge the block and mark the hash done
+		result.Transactions = txLists[index]
-	q.blockCache[index] = &Block{
+		result.Uncles = uncleLists[index]
-		RawBlock:   block,
-		OriginPeer: origin,
-	}
-	q.blockPool[block.Header().Hash()] = block.NumberU64()
 		return nil
+	}
+	return q.deliver(id, q.blockTaskPool, q.blockTaskQueue, q.blockPendPool, q.blockDonePool, bodyReqTimer, len(txLists), reconstruct)
 }
 
-// Prepare configures the block cache offset to allow accepting inbound blocks.
+// DeliverReceipts injects a receipt retrieval response into the results queue.
-func (q *queue) Prepare(offset uint64) {
+func (q *queue) DeliverReceipts(id string, receiptList [][]*types.Receipt) error {
+	reconstruct := func(header *types.Header, index int, result *fetchResult) error {
+		if types.DeriveSha(types.Receipts(receiptList[index])) != header.ReceiptHash {
+			return errInvalidReceipt
+		}
+		result.Receipts = receiptList[index]
+		return nil
+	}
+	return q.deliver(id, q.receiptTaskPool, q.receiptTaskQueue, q.receiptPendPool, q.receiptDonePool, receiptReqTimer, len(receiptList), reconstruct)
+}
+
+// deliver injects a data retrieval response into the results queue.
+func (q *queue) deliver(id string, taskPool map[common.Hash]*types.Header, taskQueue *prque.Prque, pendPool map[string]*fetchRequest,
+	donePool map[common.Hash]struct{}, reqTimer metrics.Timer, results int, reconstruct func(header *types.Header, index int, result *fetchResult) error) error {
 	q.lock.Lock()
 	defer q.lock.Unlock()
 
-	if q.blockOffset < offset {
+	// Short circuit if the data was never requested
-		q.blockOffset = offset
+	request := pendPool[id]
+	if request == nil {
+		return errNoFetchesPending
+	}
+	reqTimer.UpdateSince(request.Time)
+	delete(pendPool, id)
+
+	// If no data items were retrieved, mark them as unavailable for the origin peer
+	if results == 0 {
+		for hash, _ := range request.Headers {
+			request.Peer.ignored.Add(hash)
+		}
+	}
+	// Assemble each of the results with their headers and retrieved data parts
+	errs := make([]error, 0)
+	for i, header := range request.Headers {
+		// Short circuit assembly if no more fetch results are found
+		if i >= results {
+			break
+		}
+		// Reconstruct the next result if contents match up
+		index := int(header.Number.Int64() - int64(q.resultOffset))
+		if index >= len(q.resultCache) || index < 0 || q.resultCache[index] == nil {
+			errs = []error{errInvalidChain}
+			break
+		}
+		if err := reconstruct(header, i, q.resultCache[index]); err != nil {
+			errs = []error{err}
+			break
+		}
+		donePool[header.Hash()] = struct{}{}
+		q.resultCache[index].Pending--
+
+		// Clean up a successful fetch
+		request.Headers[i] = nil
+		delete(taskPool, header.Hash())
+	}
+	// Return all failed or missing fetches to the queue
+	for _, header := range request.Headers {
+		if header != nil {
+			taskQueue.Push(header, -float32(header.Number.Uint64()))
+		}
+	}
+	// If none of the blocks were good, it's a stale delivery
+	switch {
+	case len(errs) == 0:
+		return nil
+
+	case len(errs) == 1 && (errs[0] == errInvalidChain || errs[0] == errInvalidBody || errs[0] == errInvalidReceipt):
+		return errs[0]
+
+	case len(errs) == len(request.Headers):
+		return errStaleDelivery
+
+	default:
+		return fmt.Errorf("multiple failures: %v", errs)
 	}
 }
+
+// Prepare configures the result cache to allow accepting and caching inbound
+// fetch results.
+func (q *queue) Prepare(offset uint64, parts int) {
+	q.lock.Lock()
+	defer q.lock.Unlock()
+
+	if q.resultOffset < offset {
+		q.resultOffset = offset
+	}
+	q.resultParts = parts
+}

eth/handler.go

@@ -120,15 +120,25 @@ func NewProtocolManager(mode Mode, networkId int, mux *event.TypeMux, txpool txP
 		return nil, errIncompatibleConfig
 	}
 	// Construct the different synchronisation mechanisms
-	manager.downloader = downloader.New(manager.eventMux, manager.blockchain.HasBlock, manager.blockchain.GetBlock, manager.blockchain.CurrentBlock, manager.blockchain.GetTd, manager.blockchain.InsertChain, manager.removePeer)
+	var syncMode downloader.SyncMode
+	switch mode {
+	case ArchiveMode:
+		syncMode = downloader.FullSync
+	case FullMode:
+		syncMode = downloader.FastSync
+	case LightMode:
+		syncMode = downloader.LightSync
+	}
+	manager.downloader = downloader.New(syncMode, manager.eventMux, blockchain.HasHeader, blockchain.HasBlock, blockchain.GetHeader, blockchain.GetBlock,
+		blockchain.CurrentHeader, blockchain.CurrentBlock, blockchain.GetTd, blockchain.InsertHeaderChain, blockchain.InsertChain, nil, manager.removePeer)
 
 	validator := func(block *types.Block, parent *types.Block) error {
 		return core.ValidateHeader(pow, block.Header(), parent.Header(), true, false)
 	}
 	heighter := func() uint64 {
-		return manager.blockchain.CurrentBlock().NumberU64()
+		return blockchain.CurrentBlock().NumberU64()
 	}
-	manager.fetcher = fetcher.New(manager.blockchain.GetBlock, validator, manager.BroadcastBlock, heighter, manager.blockchain.InsertChain, manager.removePeer)
+	manager.fetcher = fetcher.New(blockchain.GetBlock, validator, manager.BroadcastBlock, heighter, blockchain.InsertChain, manager.removePeer)
 
 	return manager, nil
 }
@@ -210,7 +220,7 @@ func (pm *ProtocolManager) handle(p *peer) error {
 	// Register the peer in the downloader. If the downloader considers it banned, we disconnect
 	if err := pm.downloader.RegisterPeer(p.id, p.version, p.Head(),
 		p.RequestHashes, p.RequestHashesFromNumber, p.RequestBlocks,
-		p.RequestHeadersByHash, p.RequestHeadersByNumber, p.RequestBodies); err != nil {
+		p.RequestHeadersByHash, p.RequestHeadersByNumber, p.RequestBodies, p.RequestReceipts); err != nil {
 		return err
 	}
 	// Propagate existing transactions. new transactions appearing
@@ -514,22 +524,31 @@ func (pm *ProtocolManager) handleMsg(p *peer) error {
 		var (
 			hash     common.Hash
 			bytes    int
-			receipts []*types.Receipt
+			receipts []rlp.RawValue
 		)
-		for bytes < softResponseLimit && len(receipts) < downloader.MaxReceiptsFetch {
+		for bytes < softResponseLimit && len(receipts) < downloader.MaxReceiptFetch {
-			// Retrieve the hash of the next transaction receipt
+			// Retrieve the hash of the next block
 			if err := msgStream.Decode(&hash); err == rlp.EOL {
 				break
 			} else if err != nil {
 				return errResp(ErrDecode, "msg %v: %v", msg, err)
 			}
-			// Retrieve the requested receipt, stopping if enough was found
+			// Retrieve the requested block's receipts, skipping if unknown to us
-			if receipt := core.GetReceipt(pm.chaindb, hash); receipt != nil {
+			results := core.GetBlockReceipts(pm.chaindb, hash)
-				receipts = append(receipts, receipt)
+			if results == nil {
-				bytes += len(receipt.RlpEncode())
+				if header := pm.blockchain.GetHeader(hash); header == nil || header.ReceiptHash != types.EmptyRootHash {
+					continue
 				}
 			}
-		return p.SendReceipts(receipts)
+			// If known, encode and queue for response packet
+			if encoded, err := rlp.EncodeToBytes(results); err != nil {
+				glog.V(logger.Error).Infof("failed to encode receipt: %v", err)
+			} else {
+				receipts = append(receipts, encoded)
+				bytes += len(encoded)
+			}
+		}
+		return p.SendReceiptsRLP(receipts)
 
 	case msg.Code == NewBlockHashesMsg:
 		// Retrieve and deseralize the remote new block hashes notification

eth/handler_test.go

@@ -535,15 +535,12 @@ func testGetReceipt(t *testing.T, protocol int) {
 	defer peer.close()
 
 	// Collect the hashes to request, and the response to expect
-	hashes := []common.Hash{}
+	hashes, receipts := []common.Hash{}, []types.Receipts{}
 	for i := uint64(0); i <= pm.blockchain.CurrentBlock().NumberU64(); i++ {
-		for _, tx := range pm.blockchain.GetBlockByNumber(i).Transactions() {
+		block := pm.blockchain.GetBlockByNumber(i)
-			hashes = append(hashes, tx.Hash())
+
-		}
+		hashes = append(hashes, block.Hash())
-	}
+		receipts = append(receipts, core.GetBlockReceipts(pm.chaindb, block.Hash()))
-	receipts := make([]*types.Receipt, len(hashes))
-	for i, hash := range hashes {
-		receipts[i] = core.GetReceipt(pm.chaindb, hash)
 	}
 	// Send the hash request and verify the response
 	p2p.Send(peer.app, 0x0f, hashes)

eth/peer.go

@@ -197,9 +197,9 @@ func (p *peer) SendNodeData(data [][]byte) error {
 	return p2p.Send(p.rw, NodeDataMsg, data)
 }
 
-// SendReceipts sends a batch of transaction receipts, corresponding to the ones
+// SendReceiptsRLP sends a batch of transaction receipts, corresponding to the
-// requested.
+// ones requested from an already RLP encoded format.
-func (p *peer) SendReceipts(receipts []*types.Receipt) error {
+func (p *peer) SendReceiptsRLP(receipts []rlp.RawValue) error {
 	return p2p.Send(p.rw, ReceiptsMsg, receipts)
 }