Merge branch 'blockpool2' of https://github.com/ethersphere/go-ethereum into ethersphere-blockpool2

43 files changed, 3795 insertions, 2584 deletions

diff --git a/blockpool/blockpool.go b/blockpool/blockpool.go
new file mode 100644
index 000000000..0126d734c
--- /dev/null
+++ b/blockpool/blockpool.go
@@ -0,0 +1,749 @@
+package blockpool
+
+import (
+	"bytes"
+	"fmt"
+	"math/big"
+	"sync"
+	"time"
+
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/errs"
+	ethlogger "github.com/ethereum/go-ethereum/logger"
+	"github.com/ethereum/go-ethereum/pow"
+)
+
+var plog = ethlogger.NewLogger("Blockpool")
+
+var (
+	// max number of block hashes sent in one request
+	blockHashesBatchSize = 512
+	// max number of blocks sent in one request
+	blockBatchSize = 64
+	// interval between two consecutive block checks (and requests)
+	blocksRequestInterval = 3 * time.Second
+	// level of redundancy in block requests sent
+	blocksRequestRepetition = 1
+	// interval between two consecutive block hash checks (and requests)
+	blockHashesRequestInterval = 3 * time.Second
+	// max number of idle iterations, ie., check through a section without new blocks coming in
+	blocksRequestMaxIdleRounds = 100
+	// timeout interval: max time allowed for peer without sending a block hash
+	blockHashesTimeout = 60 * time.Second
+	// timeout interval: max time allowed for peer without sending a block
+	blocksTimeout = 120 * time.Second
+)
+
+// config embedded in components, by default fall back to constants
+// by default all resolved to local
+type Config struct {
+	BlockHashesBatchSize       int
+	BlockBatchSize             int
+	BlocksRequestRepetition    int
+	BlocksRequestMaxIdleRounds int
+	BlockHashesRequestInterval time.Duration
+	BlocksRequestInterval      time.Duration
+	BlockHashesTimeout         time.Duration
+	BlocksTimeout              time.Duration
+}
+
+// blockpool errors
+const (
+	ErrInvalidBlock = iota
+	ErrInvalidPoW
+	ErrUnrequestedBlock
+	ErrInsufficientChainInfo
+)
+
+var errorToString = map[int]string{
+	ErrInvalidBlock:          "Invalid block",
+	ErrInvalidPoW:            "Invalid PoW",
+	ErrUnrequestedBlock:      "Unrequested block",
+	ErrInsufficientChainInfo: "Insufficient chain info",
+}
+
+// init initialises all your laundry
+func (self *Config) init() {
+	if self.BlockHashesBatchSize == 0 {
+		self.BlockHashesBatchSize = blockHashesBatchSize
+	}
+	if self.BlockBatchSize == 0 {
+		self.BlockBatchSize = blockBatchSize
+	}
+	if self.BlocksRequestRepetition == 0 {
+		self.BlocksRequestRepetition = blocksRequestRepetition
+	}
+	if self.BlocksRequestMaxIdleRounds == 0 {
+		self.BlocksRequestMaxIdleRounds = blocksRequestMaxIdleRounds
+	}
+	if self.BlockHashesRequestInterval == 0 {
+		self.BlockHashesRequestInterval = blockHashesRequestInterval
+	}
+	if self.BlocksRequestInterval == 0 {
+		self.BlocksRequestInterval = blocksRequestInterval
+	}
+	if self.BlockHashesTimeout == 0 {
+		self.BlockHashesTimeout = blockHashesTimeout
+	}
+	if self.BlocksTimeout == 0 {
+		self.BlocksTimeout = blocksTimeout
+	}
+}
+
+// node is the basic unit of the internal model of block chain/tree in the blockpool
+type node struct {
+	lock    sync.RWMutex
+	hash    []byte
+	block   *types.Block
+	hashBy  string
+	blockBy string
+	td      *big.Int
+}
+
+type index struct {
+	int
+}
+
+// entry is the struct kept and indexed in the pool
+type entry struct {
+	node    *node
+	section *section
+	index   *index
+}
+
+type BlockPool struct {
+	Config *Config
+
+	// the minimal interface with blockchain
+	hasBlock    func(hash []byte) bool
+	insertChain func(types.Blocks) error
+	verifyPoW   func(pow.Block) bool
+
+	pool  map[string]*entry
+	peers *peers
+
+	lock      sync.RWMutex
+	chainLock sync.RWMutex
+	// alloc-easy pool of hash slices
+	hashSlicePool chan [][]byte
+
+	status *status
+
+	quit    chan bool
+	wg      sync.WaitGroup
+	running bool
+}
+
+// public constructor
+func New(
+	hasBlock func(hash []byte) bool,
+	insertChain func(types.Blocks) error,
+	verifyPoW func(pow.Block) bool,
+) *BlockPool {
+
+	return &BlockPool{
+		Config:      &Config{},
+		hasBlock:    hasBlock,
+		insertChain: insertChain,
+		verifyPoW:   verifyPoW,
+	}
+}
+
+// allows restart
+func (self *BlockPool) Start() {
+	self.lock.Lock()
+	defer self.lock.Unlock()
+
+	if self.running {
+		return
+	}
+
+	self.Config.init()
+	self.hashSlicePool = make(chan [][]byte, 150)
+	self.status = newStatus()
+	self.quit = make(chan bool)
+	self.pool = make(map[string]*entry)
+	self.running = true
+
+	self.peers = &peers{
+		errors: &errs.Errors{
+			Package: "Blockpool",
+			Errors:  errorToString,
+		},
+		peers:  make(map[string]*peer),
+		status: self.status,
+		bp:     self,
+	}
+	timer := time.NewTicker(3 * time.Second)
+	go func() {
+		for {
+			select {
+			case <-self.quit:
+				return
+			case <-timer.C:
+				plog.Debugf("status:\n%v", self.Status())
+			}
+		}
+	}()
+	plog.Infoln("Started")
+}
+
+func (self *BlockPool) Stop() {
+	self.lock.Lock()
+	if !self.running {
+		self.lock.Unlock()
+		return
+	}
+	self.running = false
+
+	self.lock.Unlock()
+
+	plog.Infoln("Stopping...")
+
+	close(self.quit)
+
+	self.lock.Lock()
+	self.peers = nil
+	self.pool = nil
+	self.lock.Unlock()
+
+	plog.Infoln("Stopped")
+}
+
+// Wait blocks until active processes finish
+func (self *BlockPool) Wait(t time.Duration) {
+	self.lock.Lock()
+	if !self.running {
+		self.lock.Unlock()
+		return
+	}
+	self.lock.Unlock()
+
+	plog.Infoln("Waiting for processes to complete...")
+	w := make(chan bool)
+	go func() {
+		self.wg.Wait()
+		close(w)
+	}()
+
+	select {
+	case <-w:
+		plog.Infoln("Processes complete")
+	case <-time.After(t):
+		plog.Warnf("Timeout")
+	}
+}
+
+/*
+AddPeer is called by the eth protocol instance running on the peer after
+the status message has been received with total difficulty and current block hash
+Called a second time with the same peer id, it is used to update chain info for a peer. This is used when a new (mined) block message is received.
+RemovePeer needs to be called when the peer disconnects.
+Peer info is currently not persisted across disconnects (or sessions)
+*/
+func (self *BlockPool) AddPeer(
+
+	td *big.Int, currentBlockHash []byte,
+	peerId string,
+	requestBlockHashes func([]byte) error,
+	requestBlocks func([][]byte) error,
+	peerError func(*errs.Error),
+
+) (best bool) {
+
+	return self.peers.addPeer(td, currentBlockHash, peerId, requestBlockHashes, requestBlocks, peerError)
+}
+
+// RemovePeer needs to be called when the peer disconnects
+func (self *BlockPool) RemovePeer(peerId string) {
+	self.peers.removePeer(peerId)
+}
+
+/*
+AddBlockHashes
+
+Entry point for eth protocol to add block hashes received via BlockHashesMsg
+
+only hashes from the best peer are handled
+
+initiates further hash requests until a known parent is reached (unless cancelled by a peerSwitch event, i.e., when a better peer becomes best peer)
+launches all block request processes on each chain section
+
+the first argument is an iterator function. Using this block hashes are decoded from the rlp message payload on demand. As a result, AddBlockHashes needs to run synchronously for one peer since the message is discarded if the caller thread returns.
+*/
+func (self *BlockPool) AddBlockHashes(next func() ([]byte, bool), peerId string) {
+
+	bestpeer, best := self.peers.getPeer(peerId)
+	if !best {
+		return
+	}
+	// bestpeer is still the best peer
+
+	self.wg.Add(1)
+
+	defer func() { self.wg.Done() }()
+
+	self.status.lock.Lock()
+	self.status.activePeers[bestpeer.id]++
+	self.status.lock.Unlock()
+
+	var n int
+	var hash []byte
+	var ok, headSection, peerswitch bool
+	var sec, child, parent *section
+	var entry *entry
+	var nodes []*node
+
+	hash, ok = next()
+	bestpeer.lock.Lock()
+
+	plog.Debugf("AddBlockHashes: peer <%s> starting from [%s] (peer head: %s)", peerId, hex(bestpeer.parentHash), hex(bestpeer.currentBlockHash))
+
+	// first check if we are building the head section of a peer's chain
+	if bytes.Equal(bestpeer.parentHash, hash) {
+		if self.hasBlock(bestpeer.currentBlockHash) {
+			return
+		}
+		/*
+		 when peer is promoted in switchPeer, a new header section process is launched
+		 as the head section skeleton is actually created here, it is signaled to the process
+		 so that it can quit
+		 in the special case that the node for parent of the head block is found in the blockpool
+		 (with or without fetched block)
+		*/
+		headSection = true
+		if entry := self.get(bestpeer.currentBlockHash); entry == nil {
+			plog.DebugDetailf("AddBlockHashes: peer <%s> (head: %s) head section starting from [%s] ", peerId, hex(bestpeer.currentBlockHash), hex(bestpeer.parentHash))
+			// if head block is not yet in the pool, create entry and start node list for section
+			node := &node{
+				hash:    bestpeer.currentBlockHash,
+				block:   bestpeer.currentBlock,
+				hashBy:  peerId,
+				blockBy: peerId,
+			}
+			// nodes is a list of nodes in one section ordered top-bottom (old to young)
+			nodes = append(nodes, node)
+			n++
+		} else {
+			// otherwise set child section iff found node is the root of a section
+			// this is a possible scenario when a singleton head section was created
+			// on an earlier occasion this peer or another with the same block was best peer
+			if entry.node == entry.section.bottom {
+				child = entry.section
+				plog.DebugDetailf("AddBlockHashes: peer <%s>: connects to child section root %s", peerId, hex(bestpeer.currentBlockHash))
+			}
+		}
+	} else {
+		// otherwise : we are not building the head section of the peer
+		plog.DebugDetailf("AddBlockHashes: peer <%s> (head: %s) section starting from [%s] ", peerId, hex(bestpeer.currentBlockHash), hex(hash))
+	}
+	// the switch channel signals peerswitch event
+	switchC := bestpeer.switchC
+	bestpeer.lock.Unlock()
+
+	// iterate over hashes coming from peer (first round we have hash set above)
+LOOP:
+	for ; ok; hash, ok = next() {
+
+		select {
+		case <-self.quit:
+			// global quit for blockpool
+			return
+
+		case <-switchC:
+			// if the peer is demoted, no more hashes read
+			plog.DebugDetailf("AddBlockHashes: demoted peer <%s> (head: %s)", peerId, hex(bestpeer.currentBlockHash), hex(hash))
+			peerswitch = true
+			break LOOP
+		default:
+		}
+
+		// if we reach the blockchain we stop reading more
+		if self.hasBlock(hash) {
+			// check if known block connecting the downloaded chain to our blockchain
+			plog.DebugDetailf("AddBlockHashes: peer <%s> (head: %s) found block %s in the blockchain", peerId, hex(bestpeer.currentBlockHash), hex(hash))
+			if len(nodes) == 1 {
+				// create new section if needed and push it to the blockchain
+				sec = self.newSection(nodes)
+				sec.addSectionToBlockChain(bestpeer)
+			} else {
+
+				/*
+					 not added hash yet but according to peer child section built
+					earlier chain connects with blockchain
+					this maybe a potential vulnarability
+					the root block arrives (or already there but its parenthash was not pointing to known block in the blockchain)
+					we start inserting -> error -> remove the entire chain
+					instead of punishing this peer
+					solution: when switching peers always make sure best peers own head block
+					and td together with blockBy are recorded on the node
+				*/
+				if len(nodes) == 0 && child != nil {
+					child.addSectionToBlockChain(bestpeer)
+				}
+			}
+			break LOOP
+		}
+
+		// look up node in the pool
+		entry = self.get(hash)
+		if entry != nil {
+			// reached a known chain in the pool
+			if entry.node == entry.section.bottom && n == 1 {
+				/*
+					the first block hash received is an orphan in the pool
+					this also supports clients that (despite the spec) include <from> hash in their
+					response to hashes request. Note that by providing <from> we can link sections
+					without having to wait for the root block of the child section to arrive, so it allows for superior performance
+				*/
+				plog.DebugDetailf("AddBlockHashes: peer <%s> (head: %s) found head block [%s] as root of connecting child section [%s] skipping", peerId, hex(bestpeer.currentBlockHash), hex(hash), sectionhex(entry.section))
+				// record the entry's chain section as child section
+				child = entry.section
+				continue LOOP
+			}
+			// otherwise record entry's chain section as parent connecting it to the pool
+			plog.DebugDetailf("AddBlockHashes: peer <%s> (head: %s) found block [%s] in section [%s]. Connected to pool.", peerId, hex(bestpeer.currentBlockHash), hex(hash), sectionhex(entry.section))
+			parent = entry.section
+			break LOOP
+		}
+
+		// finally if node for block hash does not exist, create it and append node to section nodes
+		node := &node{
+			hash:   hash,
+			hashBy: peerId,
+		}
+		nodes = append(nodes, node)
+	} //for
+
+	/*
+		we got here if
+		- run out of hashes (parent = nil) sent by our best peer
+		- our peer is demoted (peerswitch = true)
+		- reached blockchain or blockpool
+		- quitting
+	*/
+	self.chainLock.Lock()
+
+	plog.DebugDetailf("AddBlockHashes: peer <%s> (head: %s): %v nodes in new section", peerId, hex(bestpeer.currentBlockHash), len(nodes))
+	/*
+	  handle forks where connecting node is mid-section
+	  by splitting section at fork
+	  no splitting needed if connecting node is head of a section
+	*/
+	if parent != nil && entry != nil && entry.node != parent.top && len(nodes) > 0 {
+		plog.DebugDetailf("AddBlockHashes: peer <%s> (head: %s): fork after %s", peerId, hex(bestpeer.currentBlockHash), hex(hash))
+
+		self.splitSection(parent, entry)
+
+		self.status.lock.Lock()
+		self.status.values.Forks++
+		self.status.lock.Unlock()
+	}
+
+	/*
+	  if new section is created, link it to parent/child sections
+	  and launch section process fetching blocks and further hashes
+	*/
+	sec = self.linkSections(nodes, parent, child)
+
+	self.status.lock.Lock()
+	self.status.values.BlockHashes += len(nodes)
+	self.status.lock.Unlock()
+	plog.DebugDetailf("AddBlockHashes: peer <%s> (head: %s): section [%s] created", peerId, hex(bestpeer.currentBlockHash), sectionhex(sec))
+
+	self.chainLock.Unlock()
+
+	/*
+		if a blockpool node is reached (parent section is not nil),
+		activate section (unless our peer is demoted by now).
+		this can be the bottom half of a newly split section in case of a fork.
+		bestPeer is nil if we got here after our peer got demoted while processing.
+		in this case no activation should happen
+	*/
+	if parent != nil && !peerswitch {
+		self.activateChain(parent, bestpeer, nil)
+		plog.DebugDetailf("AddBlockHashes: peer <%s> (head: %s): parent section [%s]", peerId, hex(bestpeer.currentBlockHash), sectionhex(parent))
+	}
+
+	/*
+	  if a new section was created,
+	  register section iff head section or no child known
+	  activate it with this peer
+	*/
+	if sec != nil {
+		// switch on section process (it is paused by switchC)
+		if !peerswitch {
+			if headSection || child == nil {
+				bestpeer.lock.Lock()
+				bestpeer.sections = append(bestpeer.sections, sec.top.hash)
+				bestpeer.lock.Unlock()
+			}
+			/*
+			  request next block hashes for parent section here.
+			  but only once, repeating only when bottom block arrives,
+			  otherwise no way to check if it arrived
+			*/
+			bestpeer.requestBlockHashes(sec.bottom.hash)
+			plog.DebugDetailf("AddBlockHashes: peer <%s> (head: %s): start requesting blocks for section [%s]", peerId, hex(bestpeer.currentBlockHash), sectionhex(sec))
+			sec.activate(bestpeer)
+		} else {
+			plog.DebugDetailf("AddBlockHashes: peer <%s> (head: %s) no longer best: delay requesting blocks for section [%s]", peerId, hex(bestpeer.currentBlockHash), sectionhex(sec))
+			sec.deactivate()
+		}
+	}
+
+	// if we are processing peer's head section, signal it to headSection process that it is created
+
+	if headSection {
+		plog.DebugDetailf("AddBlockHashes: peer <%s> (head: %s) head section registered on head section process", peerId, hex(bestpeer.currentBlockHash))
+
+		var headSec *section
+		switch {
+		case sec != nil:
+			headSec = sec
+		case child != nil:
+			headSec = child
+		default:
+			headSec = parent
+		}
+		if !peerswitch {
+			plog.DebugDetailf("AddBlockHashes: peer <%s> (head: %s) head section [%s] created signalled to head section process", peerId, hex(bestpeer.currentBlockHash), sectionhex(headSec))
+			bestpeer.headSectionC <- headSec
+		}
+	}
+}
+
+/*
+	AddBlock is the entry point for the eth protocol to call when blockMsg is received.
+
+	It has a strict interpretation of the protocol in that if the block received has not been requested, it results in an error
+
+	At the same time it is opportunistic in that if a requested block may be provided by any peer.
+
+	The received block is checked for PoW. Only the first PoW-valid block for a hash is considered legit.
+*/
+func (self *BlockPool) AddBlock(block *types.Block, peerId string) {
+	hash := block.Hash()
+
+	sender, _ := self.peers.getPeer(peerId)
+	if sender == nil {
+		return
+	}
+
+	self.status.lock.Lock()
+	self.status.activePeers[peerId]++
+	self.status.lock.Unlock()
+
+	entry := self.get(hash)
+
+	// a peer's current head block is appearing the first time
+	if bytes.Equal(hash, sender.currentBlockHash) {
+		if sender.currentBlock == nil {
+			plog.Debugf("AddBlock: add head block %s for peer <%s> (head: %s)", hex(hash), peerId, hex(sender.currentBlockHash))
+			sender.setChainInfoFromBlock(block)
+			// sender.currentBlockC <- block
+
+			self.status.lock.Lock()
+			self.status.values.Blocks++
+			self.status.values.BlocksInPool++
+			self.status.lock.Unlock()
+		} else {
+			plog.DebugDetailf("AddBlock: head block %s for peer <%s> (head: %s) already known", hex(hash), peerId, hex(sender.currentBlockHash))
+		}
+	} else {
+
+		plog.DebugDetailf("AddBlock: block %s received from peer <%s> (head: %s)", hex(hash), peerId, hex(sender.currentBlockHash))
+
+		sender.lock.Lock()
+		// update peer chain info if more recent than what we registered
+		if block.Td != nil && block.Td.Cmp(sender.td) > 0 {
+			sender.td = block.Td
+			sender.currentBlockHash = block.Hash()
+			sender.parentHash = block.ParentHash()
+			sender.currentBlock = block
+			sender.headSection = nil
+		}
+		sender.lock.Unlock()
+
+		if entry == nil {
+			// penalise peer for sending what we have not asked
+			plog.DebugDetailf("AddBlock: unrequested block %s received from peer <%s> (head: %s)", hex(hash), peerId, hex(sender.currentBlockHash))
+			sender.addError(ErrUnrequestedBlock, "%x", hash)
+
+			self.status.lock.Lock()
+			self.status.badPeers[peerId]++
+			self.status.lock.Unlock()
+			return
+		}
+	}
+	if entry == nil {
+		return
+	}
+
+	node := entry.node
+	node.lock.Lock()
+	defer node.lock.Unlock()
+
+	// check if block already present
+	if node.block != nil {
+		plog.DebugDetailf("AddBlock: block %s from peer <%s> (head: %s) already sent by <%s> ", hex(hash), peerId, hex(sender.currentBlockHash), node.blockBy)
+		return
+	}
+
+	// check if block is already inserted in the blockchain
+	if self.hasBlock(hash) {
+		plog.DebugDetailf("AddBlock: block %s from peer <%s> (head: %s) already in the blockchain", hex(hash), peerId, hex(sender.currentBlockHash))
+		return
+	}
+
+	// validate block for PoW
+	if !self.verifyPoW(block) {
+		plog.Warnf("AddBlock: invalid PoW on block %s from peer  <%s> (head: %s)", hex(hash), peerId, hex(sender.currentBlockHash))
+		sender.addError(ErrInvalidPoW, "%x", hash)
+
+		self.status.lock.Lock()
+		self.status.badPeers[peerId]++
+		self.status.lock.Unlock()
+
+		return
+	}
+
+	node.block = block
+	node.blockBy = peerId
+	node.td = block.Td // optional field
+
+	self.status.lock.Lock()
+	self.status.values.Blocks++
+	self.status.values.BlocksInPool++
+	self.status.lock.Unlock()
+
+}
+
+/*
+  iterates down a chain section by section
+  activating section process on incomplete sections with peer
+  relinking orphaned sections with their parent if root block (and its parent hash) is known)
+*/
+func (self *BlockPool) activateChain(sec *section, p *peer, connected map[string]*section) {
+
+	p.lock.RLock()
+	switchC := p.switchC
+	p.lock.RUnlock()
+
+	var i int
+
+LOOP:
+	for sec != nil {
+		parent := self.getParent(sec)
+		plog.DebugDetailf("activateChain: section [%s] activated by peer <%s>", sectionhex(sec), p.id)
+		sec.activate(p)
+		if i > 0 && connected != nil {
+			connected[string(sec.top.hash)] = sec
+		}
+		/*
+		  we need to relink both complete and incomplete sections
+		  the latter could have been blockHashesRequestsComplete before being delinked from its parent
+		*/
+		if parent == nil && sec.bottom.block != nil {
+			if entry := self.get(sec.bottom.block.ParentHash()); entry != nil {
+				parent = entry.section
+				plog.DebugDetailf("activateChain: [%s]-[%s] relink", sectionhex(parent), sectionhex(sec))
+				link(parent, sec)
+			}
+		}
+		sec = parent
+
+		// stop if peer got demoted
+		select {
+		case <-switchC:
+			break LOOP
+		case <-self.quit:
+			break LOOP
+		default:
+		}
+	}
+}
+
+// must run in separate go routine, otherwise
+// switchpeer -> activateChain -> activate deadlocks on section process select and peers.lock
+func (self *BlockPool) requestBlocks(attempts int, hashes [][]byte) {
+	self.wg.Add(1)
+	go func() {
+		self.peers.requestBlocks(attempts, hashes)
+		self.wg.Done()
+	}()
+}
+
+// convenience methods to access adjacent sections
+func (self *BlockPool) getParent(sec *section) *section {
+	self.chainLock.RLock()
+	defer self.chainLock.RUnlock()
+	return sec.parent
+}
+
+func (self *BlockPool) getChild(sec *section) *section {
+	self.chainLock.RLock()
+	defer self.chainLock.RUnlock()
+	return sec.child
+}
+
+// accessor and setter for entries in the pool
+func (self *BlockPool) get(hash []byte) *entry {
+	self.lock.RLock()
+	defer self.lock.RUnlock()
+	return self.pool[string(hash)]
+}
+
+func (self *BlockPool) set(hash []byte, e *entry) {
+	self.lock.Lock()
+	defer self.lock.Unlock()
+	self.pool[string(hash)] = e
+}
+
+func (self *BlockPool) remove(sec *section) {
+	// delete node entries from pool index under pool lock
+	self.lock.Lock()
+	defer self.lock.Unlock()
+	for _, node := range sec.nodes {
+		delete(self.pool, string(node.hash))
+	}
+}
+
+func (self *BlockPool) getHashSlice() (s [][]byte) {
+	select {
+	case s = <-self.hashSlicePool:
+	default:
+		s = make([][]byte, self.Config.BlockBatchSize)
+	}
+	return
+}
+
+// Return returns a Client to the pool.
+func (self *BlockPool) putHashSlice(s [][]byte) {
+	if len(s) == self.Config.BlockBatchSize {
+		select {
+		case self.hashSlicePool <- s:
+		default:
+		}
+	}
+}
+
+// pretty prints hash (byte array) with first 4 bytes in hex
+func hex(hash []byte) (name string) {
+	if hash == nil {
+		name = ""
+	} else {
+		name = fmt.Sprintf("%x", hash[:4])
+	}
+	return
+}
+
+// pretty prints a section using first 4 bytes in hex of bottom and top blockhash of the section
+func sectionhex(section *section) (name string) {
+	if section == nil {
+		name = ""
+	} else {
+		name = fmt.Sprintf("%x-%x", section.bottom.hash[:4], section.top.hash[:4])
+	}
+	return
+}
diff --git a/blockpool/blockpool_test.go b/blockpool/blockpool_test.go
new file mode 100644
index 000000000..bca48c6ca
--- /dev/null
+++ b/blockpool/blockpool_test.go
@@ -0,0 +1,479 @@
+package blockpool
+
+import (
+	"testing"
+	"time"
+
+	"github.com/ethereum/go-ethereum/blockpool/test"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/ethutil"
+)
+
+func TestPeerWithKnownBlock(t *testing.T) {
+	test.LogInit()
+	_, blockPool, blockPoolTester := newTestBlockPool(t)
+	blockPoolTester.refBlockChain[0] = nil
+	blockPoolTester.blockChain[0] = nil
+	blockPool.Start()
+
+	peer0 := blockPoolTester.newPeer("0", 1, 0)
+	peer0.AddPeer()
+
+	blockPool.Wait(waitTimeout)
+	blockPool.Stop()
+	// no request on known block
+	peer0.checkBlockHashesRequests()
+}
+
+func TestPeerWithKnownParentBlock(t *testing.T) {
+	test.LogInit()
+	_, blockPool, blockPoolTester := newTestBlockPool(t)
+	blockPoolTester.initRefBlockChain(1)
+	blockPoolTester.blockChain[0] = nil
+	blockPool.Start()
+
+	peer0 := blockPoolTester.newPeer("0", 1, 1)
+	peer0.AddPeer()
+	peer0.serveBlocks(0, 1)
+
+	blockPool.Wait(waitTimeout)
+	blockPool.Stop()
+	peer0.checkBlocksRequests([]int{1})
+	peer0.checkBlockHashesRequests()
+	blockPoolTester.refBlockChain[1] = []int{}
+	blockPoolTester.checkBlockChain(blockPoolTester.refBlockChain)
+}
+
+func TestPeerPromotionByOptionalTdOnBlock(t *testing.T) {
+	test.LogInit()
+	_, blockPool, blockPoolTester := newTestBlockPool(t)
+	blockPoolTester.blockChain[0] = nil
+	blockPoolTester.initRefBlockChain(4)
+	peer0 := blockPoolTester.newPeer("peer0", 2, 2)
+	peer1 := blockPoolTester.newPeer("peer1", 1, 1)
+	peer2 := blockPoolTester.newPeer("peer2", 3, 4)
+
+	blockPool.Start()
+
+	// pool
+	peer0.AddPeer()
+	peer0.serveBlocks(1, 2)
+	best := peer1.AddPeer()
+	// this tests that peer1 is not promoted over peer0 yet
+	if best {
+		t.Errorf("peer1 (TD=1) should not be set as best")
+	}
+	best = peer2.AddPeer()
+	peer2.serveBlocks(3, 4)
+	peer2.serveBlockHashes(4, 3, 2, 1)
+	hashes := blockPoolTester.hashPool.IndexesToHashes([]int{2, 3})
+	peer1.waitBlocksRequests(3)
+	blockPool.AddBlock(&types.Block{
+		HeaderHash:       ethutil.Bytes(hashes[1]),
+		ParentHeaderHash: ethutil.Bytes(hashes[0]),
+		Td:               ethutil.Big3,
+	}, "peer1")
+
+	blockPool.RemovePeer("peer2")
+	if blockPool.peers.best.id != "peer1" {
+		t.Errorf("peer1 (TD=3) should be set as best")
+	}
+	peer1.serveBlocks(0, 1, 2)
+
+	blockPool.Wait(waitTimeout)
+	blockPool.Stop()
+	blockPoolTester.refBlockChain[4] = []int{}
+	blockPoolTester.checkBlockChain(blockPoolTester.refBlockChain)
+}
+
+func TestSimpleChain(t *testing.T) {
+	test.LogInit()
+	_, blockPool, blockPoolTester := newTestBlockPool(t)
+	blockPoolTester.blockChain[0] = nil
+	blockPoolTester.initRefBlockChain(2)
+
+	blockPool.Start()
+
+	peer1 := blockPoolTester.newPeer("peer1", 1, 2)
+	peer1.AddPeer()
+	peer1.serveBlocks(1, 2)
+	go peer1.serveBlockHashes(2, 1, 0)
+	peer1.serveBlocks(0, 1)
+
+	blockPool.Wait(waitTimeout)
+	blockPool.Stop()
+	blockPoolTester.refBlockChain[2] = []int{}
+	blockPoolTester.checkBlockChain(blockPoolTester.refBlockChain)
+}
+
+func TestChainConnectingWithParentHash(t *testing.T) {
+	test.LogInit()
+	_, blockPool, blockPoolTester := newTestBlockPool(t)
+	blockPoolTester.blockChain[0] = nil
+	blockPoolTester.initRefBlockChain(3)
+
+	blockPool.Start()
+
+	peer1 := blockPoolTester.newPeer("peer1", 1, 3)
+	peer1.AddPeer()
+	go peer1.serveBlocks(2, 3)
+	go peer1.serveBlockHashes(3, 2, 1)
+	peer1.serveBlocks(0, 1, 2)
+
+	blockPool.Wait(waitTimeout)
+	blockPool.Stop()
+	blockPoolTester.refBlockChain[3] = []int{}
+	blockPoolTester.checkBlockChain(blockPoolTester.refBlockChain)
+}
+
+func TestMultiSectionChain(t *testing.T) {
+	test.LogInit()
+	_, blockPool, blockPoolTester := newTestBlockPool(t)
+	blockPoolTester.blockChain[0] = nil
+	blockPoolTester.initRefBlockChain(5)
+
+	blockPool.Start()
+
+	peer1 := blockPoolTester.newPeer("peer1", 1, 5)
+
+	peer1.AddPeer()
+	go peer1.serveBlocks(4, 5)
+	go peer1.serveBlockHashes(5, 4, 3)
+	go peer1.serveBlocks(2, 3, 4)
+	go peer1.serveBlockHashes(3, 2, 1, 0)
+	peer1.serveBlocks(0, 1, 2)
+
+	blockPool.Wait(waitTimeout)
+	blockPool.Stop()
+	blockPoolTester.refBlockChain[5] = []int{}
+	blockPoolTester.checkBlockChain(blockPoolTester.refBlockChain)
+}
+
+func TestNewBlocksOnPartialChain(t *testing.T) {
+	test.LogInit()
+	_, blockPool, blockPoolTester := newTestBlockPool(t)
+	blockPoolTester.blockChain[0] = nil
+	blockPoolTester.initRefBlockChain(7)
+	blockPool.Start()
+
+	peer1 := blockPoolTester.newPeer("peer1", 1, 5)
+
+	peer1.AddPeer()
+	go peer1.serveBlocks(4, 5) // partially complete section
+	go peer1.serveBlockHashes(5, 4, 3)
+	peer1.serveBlocks(3, 4) // partially complete section
+	// peer1 found new blocks
+	peer1.td = 2
+	peer1.currentBlock = 7
+	peer1.AddPeer()
+	peer1.sendBlocks(6, 7)
+	go peer1.serveBlockHashes(7, 6, 5)
+	go peer1.serveBlocks(2, 3)
+	go peer1.serveBlocks(5, 6)
+	go peer1.serveBlockHashes(3, 2, 1) // tests that hash request from known chain root is remembered
+	peer1.serveBlocks(0, 1, 2)
+	// blockPool.RemovePeer("peer1")
+
+	blockPool.Wait(waitTimeout)
+	blockPool.Stop()
+	blockPoolTester.refBlockChain[7] = []int{}
+	blockPoolTester.checkBlockChain(blockPoolTester.refBlockChain)
+}
+
+func TestPeerSwitchUp(t *testing.T) {
+	test.LogInit()
+	_, blockPool, blockPoolTester := newTestBlockPool(t)
+	blockPoolTester.blockChain[0] = nil
+	blockPoolTester.initRefBlockChain(7)
+
+	blockPool.Start()
+
+	peer1 := blockPoolTester.newPeer("peer1", 1, 6)
+	peer2 := blockPoolTester.newPeer("peer2", 2, 7)
+
+	peer1.AddPeer()
+	go peer1.serveBlocks(5, 6)
+	go peer1.serveBlockHashes(6, 5, 4, 3) //
+	peer1.serveBlocks(2, 3)               // section partially complete, block 3 will be preserved after peer demoted
+	peer2.AddPeer()                       // peer2 is promoted as best peer, peer1 is demoted
+	go peer2.serveBlocks(6, 7)
+	// go peer2.serveBlockHashes(7, 6)       //
+	go peer2.serveBlocks(4, 5)            // tests that block request for earlier section is remembered
+	go peer1.serveBlocks(3, 4)            // tests that connecting section by demoted peer is remembered and blocks are accepted from demoted peer
+	go peer2.serveBlockHashes(3, 2, 1, 0) // tests that known chain section is activated, hash requests from 3 is remembered
+	peer2.serveBlocks(0, 1, 2)            // final blocks linking to blockchain sent
+
+	blockPool.Wait(waitTimeout)
+	blockPool.Stop()
+	blockPoolTester.refBlockChain[7] = []int{}
+	blockPoolTester.checkBlockChain(blockPoolTester.refBlockChain)
+}
+
+func TestPeerSwitchDownOverlapSectionWithoutRootBlock(t *testing.T) {
+	test.LogInit()
+	_, blockPool, blockPoolTester := newTestBlockPool(t)
+	blockPoolTester.blockChain[0] = nil
+	blockPoolTester.initRefBlockChain(6)
+	blockPool.Start()
+
+	peer1 := blockPoolTester.newPeer("peer1", 1, 4)
+	peer2 := blockPoolTester.newPeer("peer2", 2, 6)
+
+	peer2.AddPeer()
+	peer2.serveBlocks(5, 6)                  // partially complete, section will be preserved
+	peer2.serveBlockHashes(6, 5, 4)          // no go: make sure skeleton is created
+	peer1.AddPeer()                          // inferior peer1 is promoted as best peer
+	blockPool.RemovePeer("peer2")            // peer2 disconnects
+	go peer1.serveBlockHashes(4, 3, 2, 1, 0) //
+	go peer1.serveBlocks(3, 4)               //
+	go peer1.serveBlocks(4, 5)               // tests that section set by demoted peer is remembered and blocks are accepted from new peer if they have it even if peers original TD is lower
+	peer1.serveBlocks(0, 1, 2, 3)
+
+	blockPool.Wait(waitTimeout)
+	blockPool.Stop()
+	blockPoolTester.refBlockChain[6] = []int{} // tests that idle sections are not inserted in blockchain
+	blockPoolTester.checkBlockChain(blockPoolTester.refBlockChain)
+}
+
+func TestPeerSwitchDownOverlapSectionWithRootBlock(t *testing.T) {
+	test.LogInit()
+	_, blockPool, blockPoolTester := newTestBlockPool(t)
+	blockPoolTester.blockChain[0] = nil
+	blockPoolTester.initRefBlockChain(6)
+	blockPool.Start()
+
+	peer1 := blockPoolTester.newPeer("peer1", 1, 4)
+	peer2 := blockPoolTester.newPeer("peer2", 2, 6)
+
+	peer2.AddPeer()
+	peer2.serveBlocks(5, 6)                  // partially complete, section will be preserved
+	go peer2.serveBlockHashes(6, 5, 4)       //
+	peer2.serveBlocks(3, 4)                  // !incomplete section
+	time.Sleep(100 * time.Millisecond)       // make sure block 4 added
+	peer1.AddPeer()                          // inferior peer1 is promoted as best peer
+	blockPool.RemovePeer("peer2")            // peer2 disconnects
+	go peer1.serveBlockHashes(4, 3, 2, 1, 0) // tests that hash request are directly connecting if the head block exists
+	go peer1.serveBlocks(4, 5)               // tests that section set by demoted peer is remembered and blocks are accepted from new peer if they have it even if peers original TD is lower
+	peer1.serveBlocks(0, 1, 2, 3)
+
+	blockPool.Wait(waitTimeout)
+	blockPool.Stop()
+	blockPoolTester.refBlockChain[6] = []int{} // tests that idle sections are not inserted in blockchain
+	blockPoolTester.checkBlockChain(blockPoolTester.refBlockChain)
+}
+
+func TestPeerSwitchDownDisjointSection(t *testing.T) {
+	test.LogInit()
+	_, blockPool, blockPoolTester := newTestBlockPool(t)
+	blockPoolTester.blockChain[0] = nil
+	blockPoolTester.initRefBlockChain(3)
+	blockPool.Start()
+
+	peer1 := blockPoolTester.newPeer("peer1", 1, 3)
+	peer2 := blockPoolTester.newPeer("peer2", 2, 6)
+
+	peer2.AddPeer()
+	peer2.serveBlocks(5, 6)            // partially complete, section will be preserved
+	go peer2.serveBlockHashes(6, 5, 4) //
+	peer2.serveBlocks(3, 4, 5)         //
+	time.Sleep(100 * time.Millisecond) // make sure blocks are received
+	peer1.AddPeer()                    // inferior peer1 is promoted as best peer
+	blockPool.RemovePeer("peer2")      // peer2 disconnects
+	go peer1.serveBlocks(2, 3)         //
+	go peer1.serveBlockHashes(3, 2, 1) //
+	peer1.serveBlocks(0, 1, 2)         //
+
+	blockPool.Wait(waitTimeout)
+	blockPool.Stop()
+	blockPoolTester.refBlockChain[3] = []int{} // tests that idle sections are not inserted in blockchain
+	blockPoolTester.checkBlockChain(blockPoolTester.refBlockChain)
+}
+
+func TestPeerSwitchBack(t *testing.T) {
+	test.LogInit()
+	_, blockPool, blockPoolTester := newTestBlockPool(t)
+	blockPoolTester.blockChain[0] = nil
+	blockPoolTester.initRefBlockChain(8)
+
+	blockPool.Start()
+
+	peer1 := blockPoolTester.newPeer("peer1", 2, 11)
+	peer2 := blockPoolTester.newPeer("peer2", 1, 8)
+
+	peer2.AddPeer()
+	go peer2.serveBlocks(7, 8)
+	go peer2.serveBlockHashes(8, 7, 6)
+	go peer2.serveBlockHashes(6, 5, 4)
+	peer2.serveBlocks(4, 5)                  // section partially complete
+	peer1.AddPeer()                          // peer1 is promoted as best peer
+	go peer1.serveBlocks(10, 11)             //
+	peer1.serveBlockHashes(11, 10)           // only gives useless results
+	blockPool.RemovePeer("peer1")            // peer1 disconnects
+	go peer2.serveBlockHashes(4, 3, 2, 1, 0) // tests that asking for hashes from 4 is remembered
+	go peer2.serveBlocks(3, 4, 5, 6, 7, 8)   // tests that section 4, 5, 6 and 7, 8 are remembered for missing blocks
+	peer2.serveBlocks(0, 1, 2, 3)
+
+	blockPool.Wait(waitTimeout)
+	blockPool.Stop()
+	blockPoolTester.refBlockChain[8] = []int{}
+	blockPoolTester.checkBlockChain(blockPoolTester.refBlockChain)
+}
+
+func TestForkSimple(t *testing.T) {
+	test.LogInit()
+	_, blockPool, blockPoolTester := newTestBlockPool(t)
+	blockPoolTester.blockChain[0] = nil
+	blockPoolTester.initRefBlockChain(9)
+	blockPoolTester.refBlockChain[3] = []int{4, 7}
+	delete(blockPoolTester.refBlockChain, 6)
+
+	blockPool.Start()
+
+	peer1 := blockPoolTester.newPeer("peer1", 1, 9)
+	peer2 := blockPoolTester.newPeer("peer2", 2, 6)
+
+	peer1.AddPeer()
+	go peer1.serveBlocks(8, 9)
+	go peer1.serveBlockHashes(9, 8, 7, 3, 2)
+	peer1.serveBlocks(1, 2, 3, 7, 8)
+	peer2.AddPeer()                          // peer2 is promoted as best peer
+	go peer2.serveBlocks(5, 6)               //
+	go peer2.serveBlockHashes(6, 5, 4, 3, 2) // fork on 3 -> 4 (earlier child: 7)
+	go peer2.serveBlocks(1, 2, 3, 4, 5)
+	go peer2.serveBlockHashes(2, 1, 0)
+	peer2.serveBlocks(0, 1, 2)
+
+	blockPool.Wait(waitTimeout)
+	blockPool.Stop()
+	blockPoolTester.refBlockChain[6] = []int{}
+	blockPoolTester.refBlockChain[3] = []int{4}
+	delete(blockPoolTester.refBlockChain, 7)
+	delete(blockPoolTester.refBlockChain, 8)
+	delete(blockPoolTester.refBlockChain, 9)
+	blockPoolTester.checkBlockChain(blockPoolTester.refBlockChain)
+
+}
+
+func TestForkSwitchBackByNewBlocks(t *testing.T) {
+	test.LogInit()
+	_, blockPool, blockPoolTester := newTestBlockPool(t)
+	blockPoolTester.blockChain[0] = nil
+	blockPoolTester.initRefBlockChain(11)
+	blockPoolTester.refBlockChain[3] = []int{4, 7}
+	delete(blockPoolTester.refBlockChain, 6)
+
+	blockPool.Start()
+
+	peer1 := blockPoolTester.newPeer("peer1", 1, 9)
+	peer2 := blockPoolTester.newPeer("peer2", 2, 6)
+
+	peer1.AddPeer()
+	go peer1.serveBlocks(8, 9)               //
+	go peer1.serveBlockHashes(9, 8, 7, 3, 2) //
+	peer1.serveBlocks(7, 8)                  // partial section
+	// time.Sleep(1 * time.Second)
+	peer2.AddPeer()                          //
+	go peer2.serveBlocks(5, 6)               //
+	go peer2.serveBlockHashes(6, 5, 4, 3, 2) // peer2 forks on block 3
+	peer2.serveBlocks(1, 2, 3, 4, 5)         //
+
+	// peer1 finds new blocks
+	peer1.td = 3
+	peer1.currentBlock = 11
+	peer1.AddPeer()
+	go peer1.serveBlocks(10, 11)
+	go peer1.serveBlockHashes(11, 10, 9)
+	go peer1.serveBlocks(9, 10)
+	// time.Sleep(1 * time.Second)
+	go peer1.serveBlocks(3, 7)      // tests that block requests on earlier fork are remembered
+	go peer1.serveBlockHashes(2, 1) // tests that hash request from root of connecting chain section (added by demoted peer) is remembered
+	peer1.serveBlocks(0, 1)
+
+	blockPool.Wait(waitTimeout)
+	blockPool.Stop()
+	blockPoolTester.refBlockChain[11] = []int{}
+	blockPoolTester.refBlockChain[3] = []int{7}
+	delete(blockPoolTester.refBlockChain, 6)
+	delete(blockPoolTester.refBlockChain, 5)
+	delete(blockPoolTester.refBlockChain, 4)
+	blockPoolTester.checkBlockChain(blockPoolTester.refBlockChain)
+
+}
+
+func TestForkSwitchBackByPeerSwitchBack(t *testing.T) {
+	test.LogInit()
+	_, blockPool, blockPoolTester := newTestBlockPool(t)
+	blockPoolTester.blockChain[0] = nil
+	blockPoolTester.initRefBlockChain(9)
+	blockPoolTester.refBlockChain[3] = []int{4, 7}
+	delete(blockPoolTester.refBlockChain, 6)
+
+	blockPool.Start()
+
+	peer1 := blockPoolTester.newPeer("peer1", 1, 9)
+	peer2 := blockPoolTester.newPeer("peer2", 2, 6)
+
+	peer1.AddPeer()
+	go peer1.serveBlocks(8, 9)
+	go peer1.serveBlockHashes(9, 8, 7, 3, 2)
+	peer1.serveBlocks(7, 8)
+	peer2.AddPeer()
+	go peer2.serveBlocks(5, 6)               //
+	go peer2.serveBlockHashes(6, 5, 4, 3, 2) // peer2 forks on block 3
+	peer2.serveBlocks(2, 3, 4, 5)            //
+	blockPool.RemovePeer("peer2")            // peer2 disconnects, peer1 is promoted again as best peer
+	go peer1.serveBlocks(1, 2)               //
+	go peer1.serveBlockHashes(2, 1, 0)       //
+	go peer1.serveBlocks(3, 7)               // tests that block requests on earlier fork are remembered and orphan section relinks to existing parent block
+	peer1.serveBlocks(0, 1)
+
+	blockPool.Wait(waitTimeout)
+	blockPool.Stop()
+	blockPoolTester.refBlockChain[9] = []int{}
+	blockPoolTester.refBlockChain[3] = []int{7}
+	delete(blockPoolTester.refBlockChain, 6)
+	delete(blockPoolTester.refBlockChain, 5)
+	delete(blockPoolTester.refBlockChain, 4)
+	blockPoolTester.checkBlockChain(blockPoolTester.refBlockChain)
+
+}
+
+func TestForkCompleteSectionSwitchBackByPeerSwitchBack(t *testing.T) {
+	test.LogInit()
+	_, blockPool, blockPoolTester := newTestBlockPool(t)
+	blockPoolTester.blockChain[0] = nil
+	blockPoolTester.initRefBlockChain(9)
+	blockPoolTester.refBlockChain[3] = []int{4, 7}
+	delete(blockPoolTester.refBlockChain, 6)
+
+	blockPool.Start()
+
+	peer1 := blockPoolTester.newPeer("peer1", 1, 9)
+	peer2 := blockPoolTester.newPeer("peer2", 2, 6)
+
+	peer1.AddPeer()
+	go peer1.serveBlocks(8, 9)
+	go peer1.serveBlockHashes(9, 8, 7)
+	peer1.serveBlocks(3, 7, 8) // make sure this section is complete
+	time.Sleep(1 * time.Second)
+	go peer1.serveBlockHashes(7, 3, 2)       // block 3/7 is section boundary
+	peer1.serveBlocks(2, 3)                  // partially complete sections block 2 missing
+	peer2.AddPeer()                          //
+	go peer2.serveBlocks(5, 6)               //
+	go peer2.serveBlockHashes(6, 5, 4, 3, 2) // peer2 forks on block 3
+	peer2.serveBlocks(2, 3, 4, 5)            // block 2 still missing.
+	blockPool.RemovePeer("peer2")            // peer2 disconnects, peer1 is promoted again as best peer
+	// peer1.serveBlockHashes(7, 3)             // tests that hash request from fork root is remembered even though section process completed
+	go peer1.serveBlockHashes(2, 1, 0) //
+	peer1.serveBlocks(0, 1, 2)
+
+	blockPool.Wait(waitTimeout)
+	blockPool.Stop()
+	blockPoolTester.refBlockChain[9] = []int{}
+	blockPoolTester.refBlockChain[3] = []int{7}
+	delete(blockPoolTester.refBlockChain, 6)
+	delete(blockPoolTester.refBlockChain, 5)
+	delete(blockPoolTester.refBlockChain, 4)
+	blockPoolTester.checkBlockChain(blockPoolTester.refBlockChain)
+
+}
diff --git a/blockpool/blockpool_util_test.go b/blockpool/blockpool_util_test.go
new file mode 100644
index 000000000..8f0c8baa0
--- /dev/null
+++ b/blockpool/blockpool_util_test.go
@@ -0,0 +1,350 @@
+package blockpool
+
+import (
+	"fmt"
+	"math/big"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/ethereum/go-ethereum/blockpool/test"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/errs"
+	"github.com/ethereum/go-ethereum/ethutil"
+	"github.com/ethereum/go-ethereum/pow"
+)
+
+var (
+	waitTimeout                    = 60 * time.Second
+	testBlockHashesRequestInterval = 10 * time.Millisecond
+	testBlocksRequestInterval      = 10 * time.Millisecond
+	requestWatchInterval           = 10 * time.Millisecond
+)
+
+// test blockChain is an integer trie
+type blockChain map[int][]int
+
+// blockPoolTester provides the interface between tests and a blockPool
+//
+// refBlockChain is used to guide which blocks will be accepted as valid
+// blockChain gives the current state of the blockchain and
+// accumulates inserts so that we can check the resulting chain
+type blockPoolTester struct {
+	hashPool          *test.TestHashPool
+	lock              sync.RWMutex
+	reqlock           sync.RWMutex
+	blocksRequestsMap map[int]bool
+	refBlockChain     blockChain
+	blockChain        blockChain
+	blockPool         *BlockPool
+	t                 *testing.T
+}
+
+func newTestBlockPool(t *testing.T) (hashPool *test.TestHashPool, blockPool *BlockPool, b *blockPoolTester) {
+	hashPool = test.NewHashPool()
+	b = &blockPoolTester{
+		t:                 t,
+		hashPool:          hashPool,
+		blockChain:        make(blockChain),
+		refBlockChain:     make(blockChain),
+		blocksRequestsMap: make(map[int]bool),
+	}
+	b.blockPool = New(b.hasBlock, b.insertChain, b.verifyPoW)
+	blockPool = b.blockPool
+	blockPool.Config.BlockHashesRequestInterval = testBlockHashesRequestInterval
+	blockPool.Config.BlocksRequestInterval = testBlocksRequestInterval
+	return
+}
+
+func (self *blockPoolTester) Errorf(format string, params ...interface{}) {
+	fmt.Printf(format+"\n", params...)
+	self.t.Errorf(format, params...)
+}
+
+// blockPoolTester implements the 3 callbacks needed by the blockPool:
+// hasBlock, insetChain, verifyPoW
+func (self *blockPoolTester) hasBlock(block []byte) (ok bool) {
+	self.lock.RLock()
+	defer self.lock.RUnlock()
+	indexes := self.hashPool.HashesToIndexes([][]byte{block})
+	i := indexes[0]
+	_, ok = self.blockChain[i]
+	fmt.Printf("has block %v (%x...): %v\n", i, block[0:4], ok)
+	return
+}
+
+func (self *blockPoolTester) insertChain(blocks types.Blocks) error {
+	self.lock.Lock()
+	defer self.lock.Unlock()
+	var parent, child int
+	var children, refChildren []int
+	var ok bool
+	for _, block := range blocks {
+		child = self.hashPool.HashesToIndexes([][]byte{block.Hash()})[0]
+		_, ok = self.blockChain[child]
+		if ok {
+			fmt.Printf("block %v already in blockchain\n", child)
+			continue // already in chain
+		}
+		parent = self.hashPool.HashesToIndexes([][]byte{block.ParentHeaderHash})[0]
+		children, ok = self.blockChain[parent]
+		if !ok {
+			return fmt.Errorf("parent %v not in blockchain ", parent)
+		}
+		ok = false
+		var found bool
+		refChildren, found = self.refBlockChain[parent]
+		if found {
+			for _, c := range refChildren {
+				if c == child {
+					ok = true
+				}
+			}
+			if !ok {
+				return fmt.Errorf("invalid block %v", child)
+			}
+		} else {
+			ok = true
+		}
+		if ok {
+			// accept any blocks if parent not in refBlockChain
+			fmt.Errorf("blockchain insert %v -> %v\n", parent, child)
+			self.blockChain[parent] = append(children, child)
+			self.blockChain[child] = nil
+		}
+	}
+	return nil
+}
+
+func (self *blockPoolTester) verifyPoW(pblock pow.Block) bool {
+	return true
+}
+
+// test helper that compares the resulting blockChain to the desired blockChain
+func (self *blockPoolTester) checkBlockChain(blockChain map[int][]int) {
+	self.lock.RLock()
+	defer self.lock.RUnlock()
+	for k, v := range self.blockChain {
+		fmt.Printf("got: %v -> %v\n", k, v)
+	}
+	for k, v := range blockChain {
+		fmt.Printf("expected: %v -> %v\n", k, v)
+	}
+	if len(blockChain) != len(self.blockChain) {
+		self.Errorf("blockchain incorrect (zlength differ)")
+	}
+	for k, v := range blockChain {
+		vv, ok := self.blockChain[k]
+		if !ok || !test.ArrayEq(v, vv) {
+			self.Errorf("blockchain incorrect on %v -> %v (!= %v)", k, vv, v)
+		}
+	}
+}
+
+//
+
+// peerTester provides the peer callbacks for the blockPool
+// it registers actual callbacks so that the result can be compared to desired behaviour
+// provides helper functions to mock the protocol calls to the blockPool
+type peerTester struct {
+	blockHashesRequests []int
+	blocksRequests      [][]int
+	blocksRequestsMap   map[int]bool
+	peerErrors          []int
+	blockPool           *BlockPool
+	hashPool            *test.TestHashPool
+	lock                sync.RWMutex
+	bt                  *blockPoolTester
+	id                  string
+	td                  int
+	currentBlock        int
+	t                   *testing.T
+}
+
+// peerTester constructor takes hashPool and blockPool from the blockPoolTester
+func (self *blockPoolTester) newPeer(id string, td int, cb int) *peerTester {
+	return &peerTester{
+		id:                id,
+		td:                td,
+		currentBlock:      cb,
+		hashPool:          self.hashPool,
+		blockPool:         self.blockPool,
+		t:                 self.t,
+		bt:                self,
+		blocksRequestsMap: self.blocksRequestsMap,
+	}
+}
+
+func (self *peerTester) Errorf(format string, params ...interface{}) {
+	fmt.Printf(format+"\n", params...)
+	self.t.Errorf(format, params...)
+}
+
+// helper to compare actual and expected block requests
+func (self *peerTester) checkBlocksRequests(blocksRequests ...[]int) {
+	if len(blocksRequests) > len(self.blocksRequests) {
+		self.Errorf("blocks requests incorrect (length differ)\ngot %v\nexpected %v", self.blocksRequests, blocksRequests)
+	} else {
+		for i, rr := range blocksRequests {
+			r := self.blocksRequests[i]
+			if !test.ArrayEq(r, rr) {
+				self.Errorf("blocks requests incorrect\ngot %v\nexpected %v", self.blocksRequests, blocksRequests)
+			}
+		}
+	}
+}
+
+// helper to compare actual and expected block hash requests
+func (self *peerTester) checkBlockHashesRequests(blocksHashesRequests ...int) {
+	rr := blocksHashesRequests
+	self.lock.RLock()
+	r := self.blockHashesRequests
+	self.lock.RUnlock()
+	if len(r) != len(rr) {
+		self.Errorf("block hashes requests incorrect (length differ)\ngot %v\nexpected %v", r, rr)
+	} else {
+		if !test.ArrayEq(r, rr) {
+			self.Errorf("block hashes requests incorrect\ngot %v\nexpected %v", r, rr)
+		}
+	}
+}
+
+// waiter function used by peer.serveBlocks
+// blocking until requests appear
+// since block requests are sent to any random peers
+// block request map is shared between peers
+// times out after waitTimeout
+func (self *peerTester) waitBlocksRequests(blocksRequest ...int) {
+	timeout := time.After(waitTimeout)
+	rr := blocksRequest
+	for {
+		self.lock.RLock()
+		r := self.blocksRequestsMap
+		fmt.Printf("[%s] blocks request check %v (%v)\n", self.id, rr, r)
+		i := 0
+		for i = 0; i < len(rr); i++ {
+			_, ok := r[rr[i]]
+			if !ok {
+				break
+			}
+		}
+		self.lock.RUnlock()
+
+		if i == len(rr) {
+			return
+		}
+		time.Sleep(requestWatchInterval)
+		select {
+		case <-timeout:
+		default:
+		}
+	}
+}
+
+// waiter function used by peer.serveBlockHashes
+// blocking until requests appear
+// times out after a period
+func (self *peerTester) waitBlockHashesRequests(blocksHashesRequest int) {
+	timeout := time.After(waitTimeout)
+	rr := blocksHashesRequest
+	for i := 0; ; {
+		self.lock.RLock()
+		r := self.blockHashesRequests
+		self.lock.RUnlock()
+		fmt.Printf("[%s] block hash request check %v (%v)\n", self.id, rr, r)
+		for ; i < len(r); i++ {
+			if rr == r[i] {
+				return
+			}
+		}
+		time.Sleep(requestWatchInterval)
+		select {
+		case <-timeout:
+		default:
+		}
+	}
+}
+
+// mocks a simple blockchain 0 (genesis) ... n (head)
+func (self *blockPoolTester) initRefBlockChain(n int) {
+	for i := 0; i < n; i++ {
+		self.refBlockChain[i] = []int{i + 1}
+	}
+}
+
+// peerTester functions that mimic protocol calls to the blockpool
+//  registers the peer with the blockPool
+func (self *peerTester) AddPeer() bool {
+	hash := self.hashPool.IndexesToHashes([]int{self.currentBlock})[0]
+	return self.blockPool.AddPeer(big.NewInt(int64(self.td)), hash, self.id, self.requestBlockHashes, self.requestBlocks, self.peerError)
+}
+
+// peer sends blockhashes if and when gets a request
+func (self *peerTester) serveBlockHashes(indexes ...int) {
+	fmt.Printf("ready to serve block hashes %v\n", indexes)
+
+	self.waitBlockHashesRequests(indexes[0])
+	self.sendBlockHashes(indexes...)
+}
+
+func (self *peerTester) sendBlockHashes(indexes ...int) {
+	fmt.Printf("adding block hashes %v\n", indexes)
+	hashes := self.hashPool.IndexesToHashes(indexes)
+	i := 1
+	next := func() (hash []byte, ok bool) {
+		if i < len(hashes) {
+			hash = hashes[i]
+			ok = true
+			i++
+		}
+		return
+	}
+	self.blockPool.AddBlockHashes(next, self.id)
+}
+
+// peer sends blocks if and when there is a request
+// (in the shared request store, not necessarily to a person)
+func (self *peerTester) serveBlocks(indexes ...int) {
+	fmt.Printf("ready to serve blocks %v\n", indexes[1:])
+	self.waitBlocksRequests(indexes[1:]...)
+	self.sendBlocks(indexes...)
+}
+
+func (self *peerTester) sendBlocks(indexes ...int) {
+	fmt.Printf("adding blocks %v \n", indexes)
+	hashes := self.hashPool.IndexesToHashes(indexes)
+	for i := 1; i < len(hashes); i++ {
+		fmt.Printf("adding block %v %x\n", indexes[i], hashes[i][:4])
+		self.blockPool.AddBlock(&types.Block{HeaderHash: ethutil.Bytes(hashes[i]), ParentHeaderHash: ethutil.Bytes(hashes[i-1])}, self.id)
+	}
+}
+
+// peer callbacks
+// -1 is special: not found (a hash never seen)
+// records block hashes requests by the blockPool
+func (self *peerTester) requestBlockHashes(hash []byte) error {
+	indexes := self.hashPool.HashesToIndexes([][]byte{hash})
+	fmt.Printf("[%s] block hash request %v %x\n", self.id, indexes[0], hash[:4])
+	self.lock.Lock()
+	defer self.lock.Unlock()
+	self.blockHashesRequests = append(self.blockHashesRequests, indexes[0])
+	return nil
+}
+
+// records block requests by the blockPool
+func (self *peerTester) requestBlocks(hashes [][]byte) error {
+	indexes := self.hashPool.HashesToIndexes(hashes)
+	fmt.Printf("blocks request %v %x...\n", indexes, hashes[0][:4])
+	self.bt.reqlock.Lock()
+	defer self.bt.reqlock.Unlock()
+	self.blocksRequests = append(self.blocksRequests, indexes)
+	for _, i := range indexes {
+		self.blocksRequestsMap[i] = true
+	}
+	return nil
+}
+
+// records the error codes of all the peerErrors found the blockPool
+func (self *peerTester) peerError(err *errs.Error) {
+	self.peerErrors = append(self.peerErrors, err.Code)
+}
diff --git a/blockpool/config_test.go b/blockpool/config_test.go
new file mode 100644
index 000000000..c06649024
--- /dev/null
+++ b/blockpool/config_test.go
@@ -0,0 +1,40 @@
+package blockpool
+
+import (
+	"testing"
+	"time"
+
+	"github.com/ethereum/go-ethereum/blockpool/test"
+)
+
+func TestBlockPoolConfig(t *testing.T) {
+	test.LogInit()
+	blockPool := &BlockPool{Config: &Config{}}
+	blockPool.Start()
+	c := blockPool.Config
+	test.CheckInt("BlockHashesBatchSize", c.BlockHashesBatchSize, blockHashesBatchSize, t)
+	test.CheckInt("BlockBatchSize", c.BlockBatchSize, blockBatchSize, t)
+	test.CheckInt("BlocksRequestRepetition", c.BlocksRequestRepetition, blocksRequestRepetition, t)
+	test.CheckInt("BlocksRequestMaxIdleRounds", c.BlocksRequestMaxIdleRounds, blocksRequestMaxIdleRounds, t)
+	test.CheckDuration("BlockHashesRequestInterval", c.BlockHashesRequestInterval, blockHashesRequestInterval, t)
+	test.CheckDuration("BlocksRequestInterval", c.BlocksRequestInterval, blocksRequestInterval, t)
+	test.CheckDuration("BlockHashesTimeout", c.BlockHashesTimeout, blockHashesTimeout, t)
+	test.CheckDuration("BlocksTimeout", c.BlocksTimeout, blocksTimeout, t)
+}
+
+func TestBlockPoolOverrideConfig(t *testing.T) {
+	test.LogInit()
+	blockPool := &BlockPool{Config: &Config{}}
+	c := &Config{128, 32, 1, 0, 300 * time.Millisecond, 100 * time.Millisecond, 90 * time.Second, 0}
+
+	blockPool.Config = c
+	blockPool.Start()
+	test.CheckInt("BlockHashesBatchSize", c.BlockHashesBatchSize, 128, t)
+	test.CheckInt("BlockBatchSize", c.BlockBatchSize, 32, t)
+	test.CheckInt("BlocksRequestRepetition", c.BlocksRequestRepetition, blocksRequestRepetition, t)
+	test.CheckInt("BlocksRequestMaxIdleRounds", c.BlocksRequestMaxIdleRounds, blocksRequestMaxIdleRounds, t)
+	test.CheckDuration("BlockHashesRequestInterval", c.BlockHashesRequestInterval, 300*time.Millisecond, t)
+	test.CheckDuration("BlocksRequestInterval", c.BlocksRequestInterval, 100*time.Millisecond, t)
+	test.CheckDuration("BlockHashesTimeout", c.BlockHashesTimeout, 90*time.Second, t)
+	test.CheckDuration("BlocksTimeout", c.BlocksTimeout, blocksTimeout, t)
+}
diff --git a/blockpool/errors_test.go b/blockpool/errors_test.go
new file mode 100644
index 000000000..65a161233
--- /dev/null
+++ b/blockpool/errors_test.go
@@ -0,0 +1,124 @@
+package blockpool
+
+import (
+	"testing"
+	"time"
+
+	"github.com/ethereum/go-ethereum/blockpool/test"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/pow"
+)
+
+func TestInvalidBlock(t *testing.T) {
+	test.LogInit()
+	_, blockPool, blockPoolTester := newTestBlockPool(t)
+	blockPoolTester.blockChain[0] = nil
+	blockPoolTester.initRefBlockChain(2)
+	blockPoolTester.refBlockChain[2] = []int{}
+
+	blockPool.Start()
+
+	peer1 := blockPoolTester.newPeer("peer1", 1, 3)
+	peer1.AddPeer()
+	go peer1.serveBlocks(2, 3)
+	go peer1.serveBlockHashes(3, 2, 1, 0)
+	peer1.serveBlocks(0, 1, 2)
+
+	blockPool.Wait(waitTimeout)
+	blockPool.Stop()
+	blockPoolTester.refBlockChain[2] = []int{}
+	blockPoolTester.checkBlockChain(blockPoolTester.refBlockChain)
+	if len(peer1.peerErrors) == 1 {
+		if peer1.peerErrors[0] != ErrInvalidBlock {
+			t.Errorf("wrong error, got %v, expected %v", peer1.peerErrors[0], ErrInvalidBlock)
+		}
+	} else {
+		t.Errorf("expected %v error, got %v", ErrInvalidBlock, peer1.peerErrors)
+	}
+}
+
+func TestVerifyPoW(t *testing.T) {
+	test.LogInit()
+	_, blockPool, blockPoolTester := newTestBlockPool(t)
+	blockPoolTester.blockChain[0] = nil
+	blockPoolTester.initRefBlockChain(3)
+	first := false
+	blockPoolTester.blockPool.verifyPoW = func(b pow.Block) bool {
+		bb, _ := b.(*types.Block)
+		indexes := blockPoolTester.hashPool.HashesToIndexes([][]byte{bb.Hash()})
+		if indexes[0] == 2 && !first {
+			first = true
+			return false
+		} else {
+			return true
+		}
+
+	}
+
+	blockPool.Start()
+
+	peer1 := blockPoolTester.newPeer("peer1", 1, 3)
+	peer2 := blockPoolTester.newPeer("peer2", 1, 3)
+	peer1.AddPeer()
+	peer2.AddPeer()
+	go peer1.serveBlocks(2, 3)
+	go peer1.serveBlockHashes(3, 2, 1, 0)
+	peer1.serveBlocks(0, 1, 2, 3)
+	blockPoolTester.blockPool.verifyPoW = func(b pow.Block) bool {
+		return true
+	}
+	peer2.serveBlocks(1, 2)
+
+	blockPool.Wait(waitTimeout)
+	blockPool.Stop()
+	blockPoolTester.refBlockChain[3] = []int{}
+	blockPoolTester.checkBlockChain(blockPoolTester.refBlockChain)
+	if len(peer1.peerErrors) == 1 {
+		if peer1.peerErrors[0] != ErrInvalidPoW {
+			t.Errorf("wrong error, expected %v, got %v", ErrInvalidPoW, peer1.peerErrors[0])
+		}
+	} else {
+		t.Errorf("expected %v error, got %v", ErrInvalidPoW, peer1.peerErrors)
+	}
+}
+
+func TestUnrequestedBlock(t *testing.T) {
+	test.LogInit()
+	_, blockPool, blockPoolTester := newTestBlockPool(t)
+	blockPoolTester.blockChain[0] = nil
+	blockPool.Start()
+
+	peer1 := blockPoolTester.newPeer("peer1", 1, 3)
+	peer1.AddPeer()
+	peer1.sendBlocks(1, 2)
+
+	// blockPool.Wait(waitTimeout)
+	blockPool.Stop()
+	if len(peer1.peerErrors) == 1 {
+		if peer1.peerErrors[0] != ErrUnrequestedBlock {
+			t.Errorf("wrong error, got %v, expected %v", peer1.peerErrors[0], ErrUnrequestedBlock)
+		}
+	} else {
+		t.Errorf("expected %v error, got %v", ErrUnrequestedBlock, peer1.peerErrors)
+	}
+}
+
+func TestErrInsufficientChainInfo(t *testing.T) {
+	test.LogInit()
+	_, blockPool, blockPoolTester := newTestBlockPool(t)
+	blockPool.Config.BlockHashesTimeout = 100 * time.Millisecond
+	blockPool.Start()
+
+	peer1 := blockPoolTester.newPeer("peer1", 1, 3)
+	peer1.AddPeer()
+
+	blockPool.Wait(waitTimeout)
+	blockPool.Stop()
+	if len(peer1.peerErrors) == 1 {
+		if peer1.peerErrors[0] != ErrInsufficientChainInfo {
+			t.Errorf("wrong error, got %v, expected %v", peer1.peerErrors[0], ErrInsufficientChainInfo)
+		}
+	} else {
+		t.Errorf("expected %v error, got %v", ErrInsufficientChainInfo, peer1.peerErrors)
+	}
+}
diff --git a/blockpool/peers.go b/blockpool/peers.go
new file mode 100644
index 000000000..5f1b2017c
--- /dev/null
+++ b/blockpool/peers.go
@@ -0,0 +1,536 @@
+package blockpool
+
+import (
+	"bytes"
+	"math/big"
+	"math/rand"
+	"sort"
+	"sync"
+	"time"
+
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/errs"
+	"github.com/ethereum/go-ethereum/ethutil"
+)
+
+type peer struct {
+	lock sync.RWMutex
+
+	// last known blockchain status
+	td               *big.Int
+	currentBlockHash []byte
+	currentBlock     *types.Block
+	parentHash       []byte
+	headSection      *section
+
+	id string
+
+	// peer callbacks
+	requestBlockHashes func([]byte) error
+	requestBlocks      func([][]byte) error
+	peerError          func(*errs.Error)
+	errors             *errs.Errors
+
+	sections [][]byte
+
+	// channels to push new head block and head section for peer a
+	currentBlockC chan *types.Block
+	headSectionC  chan *section
+
+	// channels to signal peers witch and peer quit
+	idleC   chan bool
+	switchC chan bool
+
+	quit chan bool
+	bp   *BlockPool
+
+	// timers for head section process
+	blockHashesRequestTimer <-chan time.Time
+	blocksRequestTimer      <-chan time.Time
+	suicide                 <-chan time.Time
+
+	idle bool
+}
+
+// peers is the component keeping a record of peers in a hashmap
+//
+type peers struct {
+	lock sync.RWMutex
+
+	bp     *BlockPool
+	errors *errs.Errors
+	peers  map[string]*peer
+	best   *peer
+	status *status
+}
+
+// peer constructor
+func (self *peers) newPeer(
+	td *big.Int,
+	currentBlockHash []byte,
+	id string,
+	requestBlockHashes func([]byte) error,
+	requestBlocks func([][]byte) error,
+	peerError func(*errs.Error),
+) (p *peer) {
+
+	p = &peer{
+		errors:             self.errors,
+		td:                 td,
+		currentBlockHash:   currentBlockHash,
+		id:                 id,
+		requestBlockHashes: requestBlockHashes,
+		requestBlocks:      requestBlocks,
+		peerError:          peerError,
+		currentBlockC:      make(chan *types.Block),
+		headSectionC:       make(chan *section),
+		bp:                 self.bp,
+		idle:               true,
+	}
+	// at creation the peer is recorded in the peer pool
+	self.peers[id] = p
+	return
+}
+
+// dispatches an error to a peer if still connected
+func (self *peers) peerError(id string, code int, format string, params ...interface{}) {
+	self.lock.RLock()
+	defer self.lock.RUnlock()
+	peer, ok := self.peers[id]
+	if ok {
+		peer.addError(code, format, params)
+	}
+	// blacklisting comes here
+}
+
+func (self *peer) addError(code int, format string, params ...interface{}) {
+	err := self.errors.New(code, format, params...)
+	self.peerError(err)
+}
+
+func (self *peer) setChainInfo(td *big.Int, c []byte) {
+	self.lock.Lock()
+	defer self.lock.Unlock()
+
+	self.td = td
+	self.currentBlockHash = c
+
+	self.currentBlock = nil
+	self.parentHash = nil
+	self.headSection = nil
+}
+
+func (self *peer) setChainInfoFromBlock(block *types.Block) {
+	self.lock.Lock()
+	defer self.lock.Unlock()
+	// use the optional TD to update peer td, this helps second best peer selection
+	// in case best peer is lost
+	if block.Td != nil && block.Td.Cmp(self.td) > 0 {
+		plog.DebugDetailf("setChainInfoFromBlock: update <%s> - head: %v->%v - TD: %v->%v", self.id, hex(self.currentBlockHash), hex(block.Hash()), self.td, block.Td)
+		self.td = block.Td
+		self.currentBlockHash = block.Hash()
+		self.parentHash = block.ParentHash()
+		self.currentBlock = block
+		self.headSection = nil
+	}
+	self.bp.wg.Add(1)
+	go func() {
+		self.currentBlockC <- block
+		self.bp.wg.Done()
+	}()
+}
+
+func (self *peers) requestBlocks(attempts int, hashes [][]byte) {
+	// distribute block request among known peers
+	self.lock.RLock()
+	defer self.lock.RUnlock()
+	peerCount := len(self.peers)
+	// on first attempt use the best peer
+	if attempts == 0 {
+		plog.DebugDetailf("request %v missing blocks from best peer <%s>", len(hashes), self.best.id)
+		self.best.requestBlocks(hashes)
+		return
+	}
+	repetitions := self.bp.Config.BlocksRequestRepetition
+	if repetitions > peerCount {
+		repetitions = peerCount
+	}
+	i := 0
+	indexes := rand.Perm(peerCount)[0:repetitions]
+	sort.Ints(indexes)
+
+	plog.DebugDetailf("request %v missing blocks from %v/%v peers", len(hashes), repetitions, peerCount)
+	for _, peer := range self.peers {
+		if i == indexes[0] {
+			plog.DebugDetailf("request length: %v", len(hashes))
+			plog.DebugDetailf("request %v missing blocks [%x/%x] from peer <%s>", len(hashes), hashes[0][:4], hashes[len(hashes)-1][:4], peer.id)
+			peer.requestBlocks(hashes)
+			indexes = indexes[1:]
+			if len(indexes) == 0 {
+				break
+			}
+		}
+		i++
+	}
+	self.bp.putHashSlice(hashes)
+}
+
+// addPeer implements the logic for blockpool.AddPeer
+// returns true iff peer is promoted as best peer in the pool
+func (self *peers) addPeer(
+	td *big.Int,
+	currentBlockHash []byte,
+	id string,
+	requestBlockHashes func([]byte) error,
+	requestBlocks func([][]byte) error,
+	peerError func(*errs.Error),
+) (best bool) {
+
+	var previousBlockHash []byte
+	self.lock.Lock()
+	p, found := self.peers[id]
+	if found {
+		if !bytes.Equal(p.currentBlockHash, currentBlockHash) {
+			previousBlockHash = p.currentBlockHash
+			plog.Debugf("addPeer: Update peer <%s> with td %v and current block %s (was %v)", id, td, hex(currentBlockHash), hex(previousBlockHash))
+			p.setChainInfo(td, currentBlockHash)
+			self.status.lock.Lock()
+			self.status.values.NewBlocks++
+			self.status.lock.Unlock()
+		}
+	} else {
+		p = self.newPeer(td, currentBlockHash, id, requestBlockHashes, requestBlocks, peerError)
+
+		self.status.lock.Lock()
+
+		self.status.peers[id]++
+		self.status.values.NewBlocks++
+		self.status.lock.Unlock()
+
+		plog.Debugf("addPeer: add new peer <%v> with td %v and current block %s", id, td, hex(currentBlockHash))
+	}
+	self.lock.Unlock()
+
+	// check peer current head
+	if self.bp.hasBlock(currentBlockHash) {
+		// peer not ahead
+		return false
+	}
+
+	if self.best == p {
+		// new block update for active current best peer -> request hashes
+		plog.Debugf("addPeer: <%s> already the best peer. Request new head section info from %s", id, hex(currentBlockHash))
+
+		if previousBlockHash != nil {
+			if entry := self.bp.get(previousBlockHash); entry != nil {
+				p.headSectionC <- nil
+				self.bp.activateChain(entry.section, p, nil)
+				p.sections = append(p.sections, previousBlockHash)
+			}
+		}
+		best = true
+	} else {
+		currentTD := ethutil.Big0
+		if self.best != nil {
+			currentTD = self.best.td
+		}
+		if td.Cmp(currentTD) > 0 {
+			self.status.lock.Lock()
+			self.status.bestPeers[p.id]++
+			self.status.lock.Unlock()
+			plog.Debugf("addPeer: peer <%v> promoted best peer", id)
+			self.bp.switchPeer(self.best, p)
+			self.best = p
+			best = true
+		}
+	}
+	return
+}
+
+// removePeer is called (via RemovePeer) by the eth protocol when the peer disconnects
+func (self *peers) removePeer(id string) {
+	self.lock.Lock()
+	defer self.lock.Unlock()
+
+	p, found := self.peers[id]
+	if !found {
+		return
+	}
+
+	delete(self.peers, id)
+	plog.Debugf("addPeer: remove peer <%v>", id)
+
+	// if current best peer is removed, need to find a better one
+	if self.best == p {
+		var newp *peer
+		// FIXME: own TD
+		max := ethutil.Big0
+		// peer with the highest self-acclaimed TD is chosen
+		for _, pp := range self.peers {
+			if pp.td.Cmp(max) > 0 {
+				max = pp.td
+				newp = pp
+			}
+		}
+		if newp != nil {
+			self.status.lock.Lock()
+			self.status.bestPeers[p.id]++
+			self.status.lock.Unlock()
+			plog.Debugf("addPeer: peer <%v> with td %v promoted best peer", newp.id, newp.td)
+		} else {
+			plog.Warnln("addPeer: no suitable peers found")
+		}
+		self.best = newp
+		self.bp.switchPeer(p, newp)
+	}
+}
+
+// switchPeer launches section processes based on information about
+// shared interest and legacy of peers
+func (self *BlockPool) switchPeer(oldp, newp *peer) {
+
+	// first quit AddBlockHashes, requestHeadSection and activateChain
+	if oldp != nil {
+		plog.DebugDetailf("<%s> quit peer processes", oldp.id)
+		close(oldp.switchC)
+	}
+	if newp != nil {
+		newp.idleC = make(chan bool)
+		newp.switchC = make(chan bool)
+		// if new best peer has no head section yet, create it and run it
+		// otherwise head section is an element of peer.sections
+		if newp.headSection == nil {
+			plog.DebugDetailf("[%s] head section for [%s] not created, requesting info", newp.id, hex(newp.currentBlockHash))
+
+			if newp.idle {
+				self.wg.Add(1)
+				newp.idle = false
+				self.syncing()
+			}
+
+			go func() {
+				newp.run()
+				if !newp.idle {
+					self.wg.Done()
+					newp.idle = true
+				}
+			}()
+
+		}
+
+		var connected = make(map[string]*section)
+		var sections [][]byte
+		for _, hash := range newp.sections {
+			plog.DebugDetailf("activate chain starting from section [%s]", hex(hash))
+			// if section not connected (ie, top of a contiguous sequence of sections)
+			if connected[string(hash)] == nil {
+				// if not deleted, then reread from pool (it can be orphaned top half of a split section)
+				if entry := self.get(hash); entry != nil {
+					self.activateChain(entry.section, newp, connected)
+					connected[string(hash)] = entry.section
+					sections = append(sections, hash)
+				}
+			}
+		}
+		plog.DebugDetailf("<%s> section processes (%v non-contiguous sequences, was %v before)", newp.id, len(sections), len(newp.sections))
+		// need to lock now that newp is exposed to section processes
+		newp.lock.Lock()
+		newp.sections = sections
+		newp.lock.Unlock()
+	}
+	// finally deactivate section process for sections where newp didnt activate
+	// newp activating section process changes the quit channel for this reason
+	if oldp != nil {
+		plog.DebugDetailf("<%s> quit section processes", oldp.id)
+		//
+		close(oldp.idleC)
+	}
+}
+
+func (self *peers) getPeer(id string) (p *peer, best bool) {
+	self.lock.RLock()
+	defer self.lock.RUnlock()
+	if self.best != nil && self.best.id == id {
+		return self.best, true
+	}
+	p = self.peers[id]
+	return
+}
+
+func (self *peer) handleSection(sec *section) {
+	self.lock.Lock()
+	defer self.lock.Unlock()
+
+	self.headSection = sec
+	self.blockHashesRequestTimer = nil
+
+	if sec == nil {
+		if self.idle {
+			self.idle = false
+			self.bp.wg.Add(1)
+			self.bp.syncing()
+		}
+
+		self.suicide = time.After(self.bp.Config.BlockHashesTimeout)
+
+		plog.DebugDetailf("HeadSection: <%s> head block hash changed (mined block received). New head %s", self.id, hex(self.currentBlockHash))
+	} else {
+		if !self.idle {
+			self.idle = true
+			self.suicide = nil
+			self.bp.wg.Done()
+		}
+		plog.DebugDetailf("HeadSection: <%s> head section [%s] created", self.id, sectionhex(sec))
+	}
+}
+
+func (self *peer) getCurrentBlock(currentBlock *types.Block) {
+	// called by update or after AddBlock signals that head block of current peer is received
+	if currentBlock == nil {
+		if entry := self.bp.get(self.currentBlockHash); entry != nil {
+			entry.node.lock.Lock()
+			currentBlock = entry.node.block
+			entry.node.lock.Unlock()
+		}
+		if currentBlock != nil {
+			plog.DebugDetailf("HeadSection: <%s> head block %s found in blockpool", self.id, hex(self.currentBlockHash))
+		} else {
+			plog.DebugDetailf("HeadSection: <%s> head block %s not found... requesting it", self.id, hex(self.currentBlockHash))
+			self.requestBlocks([][]byte{self.currentBlockHash})
+			self.blocksRequestTimer = time.After(self.bp.Config.BlocksRequestInterval)
+			return
+		}
+	} else {
+		plog.DebugDetailf("HeadSection: <%s> head block %s received (parent: %s)", self.id, hex(self.currentBlockHash), hex(currentBlock.ParentHash()))
+	}
+
+	self.lock.Lock()
+	defer self.lock.Unlock()
+	self.currentBlock = currentBlock
+	self.parentHash = currentBlock.ParentHash()
+	plog.DebugDetailf("HeadSection: <%s> head block %s found (parent: [%s])... requesting  hashes", self.id, hex(self.currentBlockHash), hex(self.parentHash))
+	self.blockHashesRequestTimer = time.After(0)
+	self.blocksRequestTimer = nil
+}
+
+func (self *peer) getBlockHashes() {
+	//if connecting parent is found
+	if self.bp.hasBlock(self.parentHash) {
+		plog.DebugDetailf("HeadSection: <%s> parent block %s found in blockchain", self.id, hex(self.parentHash))
+		err := self.bp.insertChain(types.Blocks([]*types.Block{self.currentBlock}))
+		if err != nil {
+			self.addError(ErrInvalidBlock, "%v", err)
+
+			self.bp.status.lock.Lock()
+			self.bp.status.badPeers[self.id]++
+			self.bp.status.lock.Unlock()
+		}
+	} else {
+		if parent := self.bp.get(self.parentHash); parent != nil {
+			if self.bp.get(self.currentBlockHash) == nil {
+				plog.DebugDetailf("HeadSection: <%s> connecting parent %s found in pool... creating singleton section", self.id, hex(self.parentHash))
+				n := &node{
+					hash:    self.currentBlockHash,
+					block:   self.currentBlock,
+					hashBy:  self.id,
+					blockBy: self.id,
+				}
+				self.bp.newSection([]*node{n}).activate(self)
+			} else {
+				plog.DebugDetailf("HeadSection: <%s> connecting parent %s found in pool...head section [%s] exists...not requesting hashes", self.id, hex(self.parentHash), sectionhex(parent.section))
+				self.bp.activateChain(parent.section, self, nil)
+			}
+		} else {
+			plog.DebugDetailf("HeadSection: <%s> section [%s] requestBlockHashes", self.id, sectionhex(self.headSection))
+			self.requestBlockHashes(self.currentBlockHash)
+			self.blockHashesRequestTimer = time.After(self.bp.Config.BlockHashesRequestInterval)
+			return
+		}
+	}
+	self.blockHashesRequestTimer = nil
+	if !self.idle {
+		self.idle = true
+		self.suicide = nil
+		self.bp.wg.Done()
+	}
+}
+
+// main loop for head section process
+func (self *peer) run() {
+
+	self.lock.RLock()
+	switchC := self.switchC
+	currentBlockHash := self.currentBlockHash
+	self.lock.RUnlock()
+
+	self.blockHashesRequestTimer = nil
+
+	self.blocksRequestTimer = time.After(0)
+	self.suicide = time.After(self.bp.Config.BlockHashesTimeout)
+
+	var quit chan bool
+
+	var ping = time.NewTicker(5 * time.Second)
+
+LOOP:
+	for {
+		select {
+		case <-ping.C:
+			plog.Debugf("HeadSection: <%s> section with head %s, idle: %v", self.id, hex(self.currentBlockHash), self.idle)
+
+		// signal from AddBlockHashes that head section for current best peer is created
+		// if sec == nil, it signals that chain info has updated (new block message)
+		case sec := <-self.headSectionC:
+			self.handleSection(sec)
+			// local var quit channel is linked to sections suicide channel so that
+			if sec == nil {
+				quit = nil
+			} else {
+				quit = sec.suicideC
+			}
+
+		// periodic check for block hashes or parent block/section
+		case <-self.blockHashesRequestTimer:
+			self.getBlockHashes()
+
+		// signal from AddBlock that head block of current best peer has been received
+		case currentBlock := <-self.currentBlockC:
+			self.getCurrentBlock(currentBlock)
+
+		// keep requesting until found or timed out
+		case <-self.blocksRequestTimer:
+			self.getCurrentBlock(nil)
+
+		// quitting on timeout
+		case <-self.suicide:
+			self.peerError(self.bp.peers.errors.New(ErrInsufficientChainInfo, "timed out without providing block hashes or head block", currentBlockHash))
+
+			self.bp.status.lock.Lock()
+			self.bp.status.badPeers[self.id]++
+			self.bp.status.lock.Unlock()
+			// there is no persistence here, so GC will just take care of cleaning up
+			break LOOP
+
+		// signal for peer switch, quit
+		case <-switchC:
+			var complete = "incomplete "
+			if self.idle {
+				complete = "complete"
+			}
+			plog.Debugf("HeadSection: <%s> section with head %s %s... quit request loop due to peer switch", self.id, hex(self.currentBlockHash), complete)
+			break LOOP
+
+		// global quit for blockpool
+		case <-self.bp.quit:
+			break LOOP
+
+		// quit
+		case <-quit:
+			break LOOP
+		}
+	}
+	if !self.idle {
+		self.idle = true
+		self.bp.wg.Done()
+	}
+}
diff --git a/blockpool/peers_test.go b/blockpool/peers_test.go
new file mode 100644
index 000000000..e53d7160b
--- /dev/null
+++ b/blockpool/peers_test.go
@@ -0,0 +1,120 @@
+package blockpool
+
+import (
+	"math/big"
+	"testing"
+
+	"github.com/ethereum/go-ethereum/blockpool/test"
+)
+
+// the actual tests
+func TestAddPeer(t *testing.T) {
+	test.LogInit()
+	_, blockPool, blockPoolTester := newTestBlockPool(t)
+	peer0 := blockPoolTester.newPeer("peer0", 1, 0)
+	peer1 := blockPoolTester.newPeer("peer1", 2, 1)
+	peer2 := blockPoolTester.newPeer("peer2", 3, 2)
+	var bestpeer *peer
+
+	blockPool.Start()
+
+	// pool
+	best := peer0.AddPeer()
+	if !best {
+		t.Errorf("peer0 (TD=1) not accepted as best")
+	}
+	if blockPool.peers.best.id != "peer0" {
+		t.Errorf("peer0 (TD=1) not set as best")
+	}
+
+	best = peer2.AddPeer()
+	if !best {
+		t.Errorf("peer2 (TD=3) not accepted as best")
+	}
+	if blockPool.peers.best.id != "peer2" {
+		t.Errorf("peer2 (TD=3) not set as best")
+	}
+	peer2.waitBlocksRequests(2)
+
+	best = peer1.AddPeer()
+	if best {
+		t.Errorf("peer1 (TD=2) accepted as best")
+	}
+	if blockPool.peers.best.id != "peer2" {
+		t.Errorf("peer2 (TD=3) not set any more as best")
+	}
+	if blockPool.peers.best.td.Cmp(big.NewInt(int64(3))) != 0 {
+		t.Errorf("peer1 TD not set")
+	}
+
+	peer2.td = 4
+	peer2.currentBlock = 3
+	best = peer2.AddPeer()
+	if !best {
+		t.Errorf("peer2 (TD=4) not accepted as best")
+	}
+	if blockPool.peers.best.id != "peer2" {
+		t.Errorf("peer2 (TD=4) not set as best")
+	}
+	if blockPool.peers.best.td.Cmp(big.NewInt(int64(4))) != 0 {
+		t.Errorf("peer2 TD not updated")
+	}
+	peer2.waitBlocksRequests(3)
+
+	peer1.td = 3
+	peer1.currentBlock = 2
+	best = peer1.AddPeer()
+	if best {
+		t.Errorf("peer1 (TD=3) should not be set as best")
+	}
+	if blockPool.peers.best.id == "peer1" {
+		t.Errorf("peer1 (TD=3) should not be set as best")
+	}
+	bestpeer, best = blockPool.peers.getPeer("peer1")
+	if bestpeer.td.Cmp(big.NewInt(int64(3))) != 0 {
+		t.Errorf("peer1 TD should be updated")
+	}
+
+	blockPool.RemovePeer("peer2")
+	bestpeer, best = blockPool.peers.getPeer("peer2")
+	if bestpeer != nil {
+		t.Errorf("peer2 not removed")
+	}
+
+	if blockPool.peers.best.id != "peer1" {
+		t.Errorf("existing peer1 (TD=3) should be set as best peer")
+	}
+	peer1.waitBlocksRequests(2)
+
+	blockPool.RemovePeer("peer1")
+	bestpeer, best = blockPool.peers.getPeer("peer1")
+	if bestpeer != nil {
+		t.Errorf("peer1 not removed")
+	}
+
+	if blockPool.peers.best.id != "peer0" {
+		t.Errorf("existing peer0 (TD=1) should be set as best peer")
+	}
+	peer0.waitBlocksRequests(0)
+
+	blockPool.RemovePeer("peer0")
+	bestpeer, best = blockPool.peers.getPeer("peer0")
+	if bestpeer != nil {
+		t.Errorf("peer1 not removed")
+	}
+
+	// adding back earlier peer ok
+	peer0.currentBlock = 3
+	best = peer0.AddPeer()
+	if !best {
+		t.Errorf("peer0 (TD=1) should be set as best")
+	}
+
+	if blockPool.peers.best.id != "peer0" {
+		t.Errorf("peer0 (TD=1) should be set as best")
+	}
+	peer0.waitBlocksRequests(3)
+
+	blockPool.Stop()
+
+}
diff --git a/blockpool/section.go b/blockpool/section.go
new file mode 100644
index 000000000..48ea15d31
--- /dev/null
+++ b/blockpool/section.go
@@ -0,0 +1,677 @@
+package blockpool
+
+import (
+	"sync"
+	"time"
+
+	"github.com/ethereum/go-ethereum/core/types"
+)
+
+/*
+  section is the worker on each chain section in the block pool
+  - remove the section if there are blocks missing after an absolute time
+  - remove the section if there are maxIdleRounds of idle rounds of block requests with no response
+  - periodically polls the chain section for missing blocks which are then requested from peers
+  - registers the process controller on the peer so that if the peer is promoted as best peer the second time (after a disconnect of a better one), all active processes are switched back on unless they removed (inserted in blockchain, invalid or expired)
+  - when turned off (if peer disconnects and new peer connects with alternative chain), no blockrequests are made but absolute expiry timer is ticking
+  - when turned back on it recursively calls itself on the root of the next chain section
+*/
+type section struct {
+	lock sync.RWMutex
+
+	parent *section // connecting section back in time towards blockchain
+	child  *section // connecting section forward in time
+
+	top    *node // the topmost node = head node = youngest node within the chain section
+	bottom *node // the bottom node = root node = oldest node within the chain section
+	nodes  []*node
+
+	peer       *peer
+	parentHash []byte
+
+	blockHashes [][]byte
+
+	poolRootIndex int
+
+	bp *BlockPool
+
+	controlC  chan *peer     // to (de)register the current best peer
+	poolRootC chan *peer     // indicate connectedness to blockchain (well, known blocks)
+	offC      chan bool      // closed if process terminated
+	suicideC  chan bool      // initiate suicide on the section
+	quitInitC chan bool      // to signal end of initialisation
+	forkC     chan chan bool // freeze section process while splitting
+	switchC   chan bool      // switching
+	idleC     chan bool      // channel to indicate thai food
+	processC  chan *node     //
+	missingC  chan *node     //
+
+	blocksRequestTimer      <-chan time.Time
+	blockHashesRequestTimer <-chan time.Time
+	suicideTimer            <-chan time.Time
+
+	blocksRequests      int
+	blockHashesRequests int
+
+	blocksRequestsComplete      bool
+	blockHashesRequestsComplete bool
+	ready                       bool
+	same                        bool
+	initialised                 bool
+	active                      bool
+
+	step        int
+	idle        int
+	missing     int
+	lastMissing int
+	depth       int
+	invalid     bool
+	poolRoot    bool
+}
+
+//
+func (self *BlockPool) newSection(nodes []*node) *section {
+	sec := &section{
+		bottom:        nodes[len(nodes)-1],
+		top:           nodes[0],
+		nodes:         nodes,
+		poolRootIndex: len(nodes),
+		bp:            self,
+		controlC:      make(chan *peer),
+		poolRootC:     make(chan *peer),
+		offC:          make(chan bool),
+	}
+
+	for i, node := range nodes {
+		entry := &entry{node: node, section: sec, index: &index{i}}
+		self.set(node.hash, entry)
+	}
+
+	plog.DebugDetailf("[%s] setup section process", sectionhex(sec))
+
+	go sec.run()
+	return sec
+}
+
+func (self *section) addSectionToBlockChain(p *peer) {
+	self.bp.wg.Add(1)
+	go func() {
+
+		self.lock.Lock()
+		defer self.lock.Unlock()
+		defer func() {
+			self.bp.wg.Done()
+		}()
+
+		var node *node
+		var keys []string
+		var blocks []*types.Block
+		for self.poolRootIndex > 0 {
+			node = self.nodes[self.poolRootIndex-1]
+			node.lock.RLock()
+			block := node.block
+			node.lock.RUnlock()
+			if block == nil {
+				break
+			}
+			self.poolRootIndex--
+			keys = append(keys, string(node.hash))
+			blocks = append(blocks, block)
+		}
+
+		if len(blocks) == 0 {
+			return
+		}
+
+		self.bp.lock.Lock()
+		for _, key := range keys {
+			delete(self.bp.pool, key)
+		}
+		self.bp.lock.Unlock()
+
+		plog.Infof("[%s] insert %v blocks [%v/%v] into blockchain", sectionhex(self), len(blocks), hex(blocks[0].Hash()), hex(blocks[len(blocks)-1].Hash()))
+		err := self.bp.insertChain(blocks)
+		if err != nil {
+			self.invalid = true
+			self.bp.peers.peerError(node.blockBy, ErrInvalidBlock, "%v", err)
+			plog.Warnf("invalid block %x", node.hash)
+			plog.Warnf("penalise peers %v (hash), %v (block)", node.hashBy, node.blockBy)
+
+			// or invalid block and the entire chain needs to be removed
+			self.removeInvalidChain()
+		} else {
+			// if all blocks inserted in this section
+			// then need to try to insert blocks in child section
+			if self.poolRootIndex == 0 {
+				// if there is a child section, then recursively call itself:
+				// also if section process is not terminated,
+				// then signal blockchain connectivity with poolRootC
+				if child := self.bp.getChild(self); child != nil {
+					select {
+					case <-child.offC:
+						plog.DebugDetailf("[%s] add complete child section [%s] to the blockchain", sectionhex(self), sectionhex(child))
+					case child.poolRootC <- p:
+						plog.DebugDetailf("[%s] add incomplete child section [%s] to the blockchain", sectionhex(self), sectionhex(child))
+					}
+					child.addSectionToBlockChain(p)
+				} else {
+					plog.DebugDetailf("[%s] no child section in pool", sectionhex(self))
+				}
+				plog.DebugDetailf("[%s] section completely inserted to blockchain - remove", sectionhex(self))
+				// complete sections are removed. if called from within section process,
+				// this must run in its own go routine to avoid deadlock
+				self.remove()
+			}
+		}
+
+		self.bp.status.lock.Lock()
+		if err == nil {
+			headKey := string(blocks[0].ParentHash())
+			height := self.bp.status.chain[headKey] + len(blocks)
+			self.bp.status.chain[string(blocks[len(blocks)-1].Hash())] = height
+			if height > self.bp.status.values.LongestChain {
+				self.bp.status.values.LongestChain = height
+			}
+			delete(self.bp.status.chain, headKey)
+		}
+		self.bp.status.values.BlocksInChain += len(blocks)
+		self.bp.status.values.BlocksInPool -= len(blocks)
+		if err != nil {
+			self.bp.status.badPeers[node.blockBy]++
+		}
+		self.bp.status.lock.Unlock()
+
+	}()
+
+}
+
+func (self *section) run() {
+
+	// absolute time after which sub-chain is killed if not complete (some blocks are missing)
+	self.suicideC = make(chan bool)
+	self.forkC = make(chan chan bool)
+	self.suicideTimer = time.After(self.bp.Config.BlocksTimeout)
+
+	// node channels for the section
+	// container for missing block hashes
+	var checking bool
+	var ping = time.NewTicker(5 * time.Second)
+
+LOOP:
+	for !self.blockHashesRequestsComplete || !self.blocksRequestsComplete {
+
+		select {
+		case <-ping.C:
+			var name = "no peer"
+			if self.peer != nil {
+				name = self.peer.id
+			}
+			plog.DebugDetailf("[%s] peer <%s> active: %v", sectionhex(self), name, self.active)
+
+		// global quit from blockpool
+		case <-self.bp.quit:
+			break LOOP
+
+		// pause for peer switching
+		case <-self.switchC:
+			self.switchC = nil
+
+		case p := <-self.poolRootC:
+			// signal on pool root channel indicates that the blockpool is
+			// connected to the blockchain, insert the longest chain of blocks
+			// ignored in idle mode to avoid inserting chain sections of non-live peers
+			self.poolRoot = true
+			// switch off hash requests in case they were on
+			self.blockHashesRequestTimer = nil
+			self.blockHashesRequestsComplete = true
+			self.switchOn(p)
+
+		// peer quit or demoted, put section in idle mode
+		case <-self.idleC:
+			// peer quit or demoted, put section in idle mode
+			plog.Debugf("[%s] peer <%s> quit or demoted", sectionhex(self), self.peer.id)
+			self.switchOff()
+			self.idleC = nil
+
+		// timebomb - if section is not complete in time, nuke the entire chain
+		case <-self.suicideTimer:
+			self.suicide()
+			plog.Debugf("[%s] timeout. (%v total attempts): missing %v/%v/%v...suicide", sectionhex(self), self.blocksRequests, self.missing, self.lastMissing, self.depth)
+			self.suicideTimer = nil
+
+		// closing suicideC triggers section suicide: removes section nodes from pool and terminates section process
+		case <-self.suicideC:
+			plog.DebugDetailf("[%s] suicide", sectionhex(self))
+			self.unlink()
+			self.bp.remove(self)
+			plog.DebugDetailf("[%s] done", sectionhex(self))
+			break LOOP
+
+		// alarm for checking blocks in the section
+		case <-self.blocksRequestTimer:
+			plog.DebugDetailf("[%s] alarm: block request time", sectionhex(self))
+			self.processC = self.missingC
+
+		// alarm for checking parent of the section or sending out hash requests
+		case <-self.blockHashesRequestTimer:
+			plog.DebugDetailf("[%s] alarm: hash request time", sectionhex(self))
+			self.blockHashesRequest()
+
+		// activate this section process with a peer
+		case p := <-self.controlC:
+			if p == nil {
+				self.switchOff()
+			} else {
+				self.switchOn(p)
+			}
+			self.bp.wg.Done()
+		// blocks the process until section is split at the fork
+		case waiter := <-self.forkC:
+			<-waiter
+			self.initialised = false
+			self.quitInitC = nil
+
+		//
+		case n, ok := <-self.processC:
+			// channel closed, first iteration finished
+			if !ok && !self.initialised {
+				plog.DebugDetailf("[%s] section initalised: missing %v/%v/%v", sectionhex(self), self.missing, self.lastMissing, self.depth)
+				self.initialised = true
+				self.processC = nil
+				// self.processC = make(chan *node, self.missing)
+				self.checkRound()
+				checking = false
+				break
+			}
+			plog.DebugDetailf("[%s] section proc step %v: missing %v/%v/%v", sectionhex(self), self.step, self.missing, self.lastMissing, self.depth)
+			if !checking {
+				self.step = 0
+				self.missing = 0
+				checking = true
+			}
+			self.step++
+
+			n.lock.RLock()
+			block := n.block
+			n.lock.RUnlock()
+
+			// if node has no block, request it (buffer it for batch request)
+			// feed it to missingC channel for the next round
+			if block == nil {
+				pos := self.missing % self.bp.Config.BlockBatchSize
+				if pos == 0 {
+					if self.missing != 0 {
+						self.bp.requestBlocks(self.blocksRequests, self.blockHashes[:])
+					}
+					self.blockHashes = self.bp.getHashSlice()
+				}
+				self.blockHashes[pos] = n.hash
+				self.missing++
+				self.missingC <- n
+			} else {
+				// checking for parent block
+				if self.poolRoot {
+					// if node has got block (received via async AddBlock call from protocol)
+					if self.step == self.lastMissing {
+						// current root of the pool
+						plog.DebugDetailf("[%s] received block for current pool root %s", sectionhex(self), hex(n.hash))
+						self.addSectionToBlockChain(self.peer)
+					}
+				} else {
+					if self.parentHash == nil && n == self.bottom {
+						self.parentHash = block.ParentHash()
+						plog.DebugDetailf("[%s] got parent head block hash %s...checking", sectionhex(self), hex(self.parentHash))
+						self.blockHashesRequest()
+					}
+				}
+			}
+			if self.initialised && self.step == self.lastMissing {
+				plog.DebugDetailf("[%s] check if new blocks arrived (attempt %v): missing %v/%v/%v", sectionhex(self), self.blocksRequests, self.missing, self.lastMissing, self.depth)
+				self.checkRound()
+				checking = false
+			}
+		} // select
+	} // for
+
+	close(self.offC)
+	if self.peer != nil {
+		self.active = false
+		self.bp.wg.Done()
+	}
+
+	plog.DebugDetailf("[%s] section process terminated: %v blocks retrieved (%v attempts), hash requests complete on root (%v attempts).", sectionhex(self), self.depth, self.blocksRequests, self.blockHashesRequests)
+
+}
+
+func (self *section) switchOn(newpeer *peer) {
+
+	oldpeer := self.peer
+	// reset switchC/switchC to current best peer
+	self.idleC = newpeer.idleC
+	self.switchC = newpeer.switchC
+	self.peer = newpeer
+
+	if oldpeer != newpeer {
+		oldp := "no peer"
+		newp := "no peer"
+		if oldpeer != nil {
+			oldp = oldpeer.id
+		}
+		if newpeer != nil {
+			newp = newpeer.id
+		}
+
+		plog.DebugDetailf("[%s] active mode <%s> -> <%s>", sectionhex(self), oldp, newp)
+	}
+
+	// activate section with current peer
+	if oldpeer == nil {
+		self.bp.wg.Add(1)
+		self.active = true
+
+		if !self.blockHashesRequestsComplete {
+			self.blockHashesRequestTimer = time.After(0)
+		}
+		if !self.blocksRequestsComplete {
+			if !self.initialised {
+				if self.quitInitC != nil {
+					<-self.quitInitC
+				}
+				self.missingC = make(chan *node, self.bp.Config.BlockHashesBatchSize)
+				self.processC = make(chan *node, self.bp.Config.BlockHashesBatchSize)
+				self.quitInitC = make(chan bool)
+
+				self.step = 0
+				self.missing = 0
+				self.depth = len(self.nodes)
+				self.lastMissing = self.depth
+
+				self.feedNodes()
+			} else {
+				self.blocksRequestTimer = time.After(0)
+			}
+		}
+	}
+}
+
+// put the section to idle mode
+func (self *section) switchOff() {
+	// active -> idle
+	if self.peer != nil {
+		oldp := "no peer"
+		oldpeer := self.peer
+		if oldpeer != nil {
+			oldp = oldpeer.id
+		}
+		plog.DebugDetailf("[%s] idle mode peer <%s> -> <> (%v total attempts): missing %v/%v/%v", sectionhex(self), oldp, self.blocksRequests, self.missing, self.lastMissing, self.depth)
+
+		self.active = false
+		self.peer = nil
+		// turn off timers
+		self.blocksRequestTimer = nil
+		self.blockHashesRequestTimer = nil
+
+		if self.quitInitC != nil {
+			<-self.quitInitC
+			self.quitInitC = nil
+		}
+		self.processC = nil
+		self.bp.wg.Done()
+	}
+}
+
+// iterates through nodes of a section to feed processC
+// used to initialise chain section
+func (self *section) feedNodes() {
+	// if not run at least once fully, launch iterator
+	self.bp.wg.Add(1)
+	go func() {
+		self.lock.Lock()
+		defer self.lock.Unlock()
+		defer func() {
+			self.bp.wg.Done()
+		}()
+		var n *node
+	INIT:
+		for _, n = range self.nodes {
+			select {
+			case self.processC <- n:
+			case <-self.bp.quit:
+				break INIT
+			}
+		}
+		close(self.processC)
+		close(self.quitInitC)
+	}()
+}
+
+func (self *section) blockHashesRequest() {
+
+	if self.switchC != nil {
+		self.bp.chainLock.Lock()
+		parentSection := self.parent
+
+		if parentSection == nil {
+
+			// only link to new parent if not switching peers
+			// this protects against synchronisation issue where during switching
+			// a demoted peer's fork will be chosen over the best peer's chain
+			// because relinking the correct chain (activateChain) is overwritten here in
+			// demoted peer's section process just before the section is put to idle mode
+			if self.parentHash != nil {
+				if parent := self.bp.get(self.parentHash); parent != nil {
+					parentSection = parent.section
+					plog.DebugDetailf("[%s] blockHashesRequest: parent section [%s] linked\n", sectionhex(self), sectionhex(parentSection))
+					link(parentSection, self)
+				} else {
+					if self.bp.hasBlock(self.parentHash) {
+						self.poolRoot = true
+						plog.DebugDetailf("[%s] blockHashesRequest: parentHash known ... inserting section in blockchain", sectionhex(self))
+						self.addSectionToBlockChain(self.peer)
+						self.blockHashesRequestTimer = nil
+						self.blockHashesRequestsComplete = true
+					}
+				}
+			}
+		}
+		self.bp.chainLock.Unlock()
+
+		if !self.poolRoot {
+			if parentSection != nil {
+				//  activate parent section with this peer
+				// but only if not during switch mode
+				plog.DebugDetailf("[%s] parent section [%s] activated\n", sectionhex(self), sectionhex(parentSection))
+				self.bp.activateChain(parentSection, self.peer, nil)
+				// if not root of chain, switch off
+				plog.DebugDetailf("[%s] parent found, hash requests deactivated (after %v total attempts)\n", sectionhex(self), self.blockHashesRequests)
+				self.blockHashesRequestTimer = nil
+				self.blockHashesRequestsComplete = true
+			} else {
+				self.blockHashesRequests++
+				plog.DebugDetailf("[%s] hash request on root (%v total attempts)\n", sectionhex(self), self.blockHashesRequests)
+				self.peer.requestBlockHashes(self.bottom.hash)
+				self.blockHashesRequestTimer = time.After(self.bp.Config.BlockHashesRequestInterval)
+			}
+		}
+	}
+}
+
+// checks number of missing blocks after each round of request and acts accordingly
+func (self *section) checkRound() {
+	if self.missing == 0 {
+		// no missing blocks
+		plog.DebugDetailf("[%s] section checked: got all blocks. process complete (%v total blocksRequests): missing %v/%v/%v", sectionhex(self), self.blocksRequests, self.missing, self.lastMissing, self.depth)
+		self.blocksRequestsComplete = true
+		self.blocksRequestTimer = nil
+	} else {
+		// some missing blocks
+		plog.DebugDetailf("[%s] section checked: missing %v/%v/%v", sectionhex(self), self.missing, self.lastMissing, self.depth)
+		self.blocksRequests++
+		pos := self.missing % self.bp.Config.BlockBatchSize
+		if pos == 0 {
+			pos = self.bp.Config.BlockBatchSize
+		}
+		self.bp.requestBlocks(self.blocksRequests, self.blockHashes[:pos])
+
+		// handle idle rounds
+		if self.missing == self.lastMissing {
+			// idle round
+			if self.same {
+				// more than once
+				self.idle++
+				// too many idle rounds
+				if self.idle >= self.bp.Config.BlocksRequestMaxIdleRounds {
+					plog.DebugDetailf("[%s] block requests had %v idle rounds (%v total attempts): missing %v/%v/%v\ngiving up...", sectionhex(self), self.idle, self.blocksRequests, self.missing, self.lastMissing, self.depth)
+					self.suicide()
+				}
+			} else {
+				self.idle = 0
+			}
+			self.same = true
+		} else {
+			self.same = false
+		}
+		self.lastMissing = self.missing
+		// put processC offline
+		self.processC = nil
+		self.blocksRequestTimer = time.After(self.bp.Config.BlocksRequestInterval)
+	}
+}
+
+/*
+ link connects two sections via parent/child fields
+ creating a doubly linked list
+ caller must hold BlockPool chainLock
+*/
+func link(parent *section, child *section) {
+	if parent != nil {
+		exChild := parent.child
+		parent.child = child
+		if exChild != nil && exChild != child {
+			if child != nil {
+				// if child is nil it is not a real fork
+				plog.DebugDetailf("[%s] chain fork [%s] -> [%s]", sectionhex(parent), sectionhex(exChild), sectionhex(child))
+			}
+			exChild.parent = nil
+		}
+	}
+	if child != nil {
+		exParent := child.parent
+		if exParent != nil && exParent != parent {
+			if parent != nil {
+				// if parent is nil it is not a real fork, but suicide delinking section
+				plog.DebugDetailf("[%s] chain reverse fork [%s] -> [%s]", sectionhex(child), sectionhex(exParent), sectionhex(parent))
+			}
+			exParent.child = nil
+		}
+		child.parent = parent
+	}
+}
+
+/*
+  handle forks where connecting node is mid-section
+  by splitting section at fork
+  no splitting needed if connecting node is head of a section
+  caller must hold chain lock
+*/
+func (self *BlockPool) splitSection(parent *section, entry *entry) {
+	plog.DebugDetailf("[%s] split section at fork", sectionhex(parent))
+	parent.deactivate()
+	waiter := make(chan bool)
+	parent.wait(waiter)
+	chain := parent.nodes
+	parent.nodes = chain[entry.index.int:]
+	parent.top = parent.nodes[0]
+	parent.poolRootIndex -= entry.index.int
+	orphan := self.newSection(chain[0:entry.index.int])
+	link(orphan, parent.child)
+	close(waiter)
+	orphan.deactivate()
+}
+
+func (self *section) wait(waiter chan bool) {
+	self.forkC <- waiter
+}
+
+func (self *BlockPool) linkSections(nodes []*node, parent, child *section) (sec *section) {
+	// if new section is created, link it to parent/child sections
+	// and launch section process fetching block and further hashes
+	if len(nodes) > 0 {
+		sec = self.newSection(nodes)
+		plog.Debugf("[%s]->[%s](%v)->[%s] new chain section", sectionhex(parent), sectionhex(sec), len(nodes), sectionhex(child))
+		link(parent, sec)
+		link(sec, child)
+	} else {
+		// now this can only happen if we allow response to hash request to include <from> hash
+		// in this case we just link parent and child (without needing root block of child section)
+		plog.Debugf("[%s]->[%s] connecting known sections", sectionhex(parent), sectionhex(child))
+		link(parent, child)
+	}
+	return
+}
+
+func (self *section) activate(p *peer) {
+	self.bp.wg.Add(1)
+	select {
+	case <-self.offC:
+		self.bp.wg.Done()
+	case self.controlC <- p:
+		plog.DebugDetailf("[%s] activate section process for peer <%s>", sectionhex(self), p.id)
+	}
+}
+
+func (self *section) deactivate() {
+	self.bp.wg.Add(1)
+	self.controlC <- nil
+}
+
+func (self *section) suicide() {
+	select {
+	case <-self.suicideC:
+		return
+	default:
+	}
+	close(self.suicideC)
+}
+
+// removes this section exacly
+func (self *section) remove() {
+	select {
+	case <-self.offC:
+		// section is complete, no process
+		self.unlink()
+		self.bp.remove(self)
+		close(self.suicideC)
+		plog.DebugDetailf("[%s] remove: suicide", sectionhex(self))
+	case <-self.suicideC:
+		plog.DebugDetailf("[%s] remove: suicided already", sectionhex(self))
+	default:
+		plog.DebugDetailf("[%s] remove: suicide", sectionhex(self))
+		close(self.suicideC)
+	}
+	plog.DebugDetailf("[%s] removed section.", sectionhex(self))
+
+}
+
+// remove a section and all its descendents from the pool
+func (self *section) removeInvalidChain() {
+	// need to get the child before removeSection delinks the section
+	self.bp.chainLock.RLock()
+	child := self.child
+	self.bp.chainLock.RUnlock()
+
+	plog.DebugDetailf("[%s] remove invalid chain", sectionhex(self))
+	self.remove()
+	if child != nil {
+		child.removeInvalidChain()
+	}
+}
+
+// unlink a section from its parent/child
+func (self *section) unlink() {
+	// first delink from child and parent under chainlock
+	self.bp.chainLock.Lock()
+	link(nil, self)
+	link(self, nil)
+	self.bp.chainLock.Unlock()
+}
diff --git a/blockpool/status.go b/blockpool/status.go
new file mode 100644
index 000000000..0dd874232
--- /dev/null
+++ b/blockpool/status.go
@@ -0,0 +1,110 @@
+package blockpool
+
+import (
+	"fmt"
+	"sync"
+)
+
+type statusValues struct {
+	BlockHashes       int    // number of hashes fetched this session
+	BlockHashesInPool int    // number of hashes currently in  the pool
+	Blocks            int    // number of blocks fetched this session
+	BlocksInPool      int    // number of blocks currently in  the pool
+	BlocksInChain     int    // number of blocks inserted/connected to the blockchain this session
+	NewBlocks         int    // number of new blocks (received with new blocks msg) this session
+	Forks             int    // number of chain forks in the blockchain (poolchain) this session
+	LongestChain      int    // the longest chain inserted since the start of session (aka session blockchain height)
+	BestPeer          []byte //Pubkey
+	Syncing           bool   // requesting, updating etc
+	Peers             int    // cumulative number of all different registered peers since the start of this session
+	ActivePeers       int    // cumulative number of all different peers that contributed a hash or block since the start of this session
+	LivePeers         int    // number of live peers registered with the block pool (supposed to be redundant but good sanity check
+	BestPeers         int    // cumulative number of all peers that at some point were promoted as best peer (peer with highest TD status) this session
+	BadPeers          int    // cumulative number of all peers that violated the protocol (invalid block or pow, unrequested hash or block, etc)
+}
+
+type status struct {
+	lock        sync.Mutex
+	values      statusValues
+	chain       map[string]int
+	peers       map[string]int
+	bestPeers   map[string]int
+	badPeers    map[string]int
+	activePeers map[string]int
+}
+
+func newStatus() *status {
+	return &status{
+		chain:       make(map[string]int),
+		peers:       make(map[string]int),
+		bestPeers:   make(map[string]int),
+		badPeers:    make(map[string]int),
+		activePeers: make(map[string]int),
+	}
+}
+
+type Status struct {
+	statusValues
+}
+
+// blockpool status for reporting
+func (self *BlockPool) Status() *Status {
+	self.status.lock.Lock()
+	defer self.status.lock.Unlock()
+	self.status.values.BlockHashesInPool = len(self.pool)
+	self.status.values.ActivePeers = len(self.status.activePeers)
+	self.status.values.BestPeers = len(self.status.bestPeers)
+	self.status.values.BadPeers = len(self.status.badPeers)
+	self.status.values.LivePeers = len(self.peers.peers)
+	self.status.values.Peers = len(self.status.peers)
+	self.status.values.BlockHashesInPool = len(self.pool)
+	return &Status{self.status.values}
+}
+
+func (self *Status) String() string {
+	return fmt.Sprintf(`
+  Syncing:            %v
+  BlockHashes:        %v
+  BlockHashesInPool:  %v
+  Blocks:             %v
+  BlocksInPool:       %v
+  BlocksInChain:      %v
+  NewBlocks:          %v
+  Forks:              %v
+  LongestChain:       %v
+  Peers:              %v
+  LivePeers:          %v
+  ActivePeers:        %v
+  BestPeers:          %v
+  BadPeers:           %v
+`,
+		self.Syncing,
+		self.BlockHashes,
+		self.BlockHashesInPool,
+		self.Blocks,
+		self.BlocksInPool,
+		self.BlocksInChain,
+		self.NewBlocks,
+		self.Forks,
+		self.LongestChain,
+		self.Peers,
+		self.LivePeers,
+		self.ActivePeers,
+		self.BestPeers,
+		self.BadPeers,
+	)
+}
+
+func (self *BlockPool) syncing() {
+	self.status.lock.Lock()
+	defer self.status.lock.Unlock()
+	if !self.status.values.Syncing {
+		self.status.values.Syncing = true
+		go func() {
+			self.wg.Wait()
+			self.status.lock.Lock()
+			self.status.values.Syncing = false
+			self.status.lock.Unlock()
+		}()
+	}
+}
diff --git a/blockpool/status_test.go b/blockpool/status_test.go
new file mode 100644
index 000000000..7392f667a
--- /dev/null
+++ b/blockpool/status_test.go
@@ -0,0 +1,228 @@
+package blockpool
+
+import (
+	"fmt"
+	"testing"
+	// "time"
+
+	"github.com/ethereum/go-ethereum/blockpool/test"
+)
+
+var statusFields = []string{
+	"BlockHashes",
+	"BlockHashesInPool",
+	"Blocks",
+	"BlocksInPool",
+	"BlocksInChain",
+	"NewBlocks",
+	"Forks",
+	"LongestChain",
+	"Peers",
+	"LivePeers",
+	"ActivePeers",
+	"BestPeers",
+	"BadPeers",
+}
+
+func getStatusValues(s *Status) []int {
+	return []int{
+		s.BlockHashes,
+		s.BlockHashesInPool,
+		s.Blocks,
+		s.BlocksInPool,
+		s.BlocksInChain,
+		s.NewBlocks,
+		s.Forks,
+		s.LongestChain,
+		s.Peers,
+		s.LivePeers,
+		s.ActivePeers,
+		s.BestPeers,
+		s.BadPeers,
+	}
+}
+
+func checkStatus(t *testing.T, bp *BlockPool, syncing bool, expected []int) (err error) {
+	s := bp.Status()
+	if s.Syncing != syncing {
+		t.Errorf("status for Syncing incorrect. expected %v, got %v", syncing, s.Syncing)
+	}
+	got := getStatusValues(s)
+	for i, v := range expected {
+		err = test.CheckInt(statusFields[i], got[i], v, t)
+		if err != nil {
+			return err
+		}
+		fmt.Printf("%v: %v (%v)\n", statusFields[i], got[i], v)
+	}
+	return
+}
+
+// func TestBlockPoolStatus(t *testing.T) {
+// 	test.LogInit()
+// 	_, blockPool, blockPoolTester := newTestBlockPool(t)
+// 	blockPoolTester.blockChain[0] = nil
+// 	blockPoolTester.initRefBlockChain(12)
+// 	blockPoolTester.refBlockChain[3] = []int{4, 7}
+// 	delete(blockPoolTester.refBlockChain, 6)
+
+// 	blockPool.Start()
+
+// 	peer1 := blockPoolTester.newPeer("peer1", 1, 9)
+// 	peer2 := blockPoolTester.newPeer("peer2", 2, 6)
+// 	peer3 := blockPoolTester.newPeer("peer3", 3, 11)
+// 	peer4 := blockPoolTester.newPeer("peer4", 1, 9)
+// 	peer2.blocksRequestsMap = peer1.blocksRequestsMap
+
+// 	var expected []int
+// 	var err error
+// 	expected = []int{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
+// 	err = checkStatus(t, blockPool, false, expected)
+// 	if err != nil {
+// 		return
+// 	}
+
+// 	peer1.AddPeer()
+// 	expected = []int{0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 1, 0}
+// 	err = checkStatus(t, blockPool, true, expected)
+// 	if err != nil {
+// 		return
+// 	}
+
+// 	peer1.serveBlocks(8, 9)
+// 	expected = []int{0, 0, 1, 1, 0, 1, 0, 0, 1, 1, 1, 1, 0}
+// 	err = checkStatus(t, blockPool, true, expected)
+// 	if err != nil {
+// 		return
+// 	}
+
+// 	peer1.serveBlockHashes(9, 8, 7, 3, 2)
+// 	expected = []int{5, 5, 1, 1, 0, 1, 0, 0, 1, 1, 1, 1, 0}
+// 	err = checkStatus(t, blockPool, true, expected)
+// 	if err != nil {
+// 		return
+// 	}
+
+// 	peer1.serveBlocks(3, 7, 8)
+// 	expected = []int{5, 5, 3, 3, 0, 1, 0, 0, 1, 1, 1, 1, 0}
+// 	err = checkStatus(t, blockPool, true, expected)
+// 	if err != nil {
+// 		return
+// 	}
+
+// 	peer1.serveBlocks(2, 3)
+// 	expected = []int{5, 5, 4, 4, 0, 1, 0, 0, 1, 1, 1, 1, 0}
+// 	err = checkStatus(t, blockPool, true, expected)
+// 	if err != nil {
+// 		return
+// 	}
+
+// 	peer4.AddPeer()
+// 	expected = []int{5, 5, 4, 4, 0, 2, 0, 0, 2, 2, 1, 1, 0}
+// 	err = checkStatus(t, blockPool, true, expected)
+// 	if err != nil {
+// 		return
+// 	}
+
+// 	peer4.sendBlockHashes(12, 11)
+// 	expected = []int{5, 5, 4, 4, 0, 2, 0, 0, 2, 2, 1, 1, 0}
+// 	err = checkStatus(t, blockPool, true, expected)
+// 	if err != nil {
+// 		return
+// 	}
+
+// 	peer2.AddPeer()
+// 	expected = []int{5, 5, 4, 4, 0, 3, 0, 0, 3, 3, 1, 2, 0}
+// 	err = checkStatus(t, blockPool, true, expected)
+// 	if err != nil {
+// 		return
+// 	}
+
+// 	peer2.serveBlocks(5, 6)
+// 	peer2.serveBlockHashes(6, 5, 4, 3, 2)
+// 	expected = []int{8, 8, 5, 5, 0, 3, 1, 0, 3, 3, 2, 2, 0}
+// 	err = checkStatus(t, blockPool, true, expected)
+// 	if err != nil {
+// 		return
+// 	}
+
+// 	peer2.serveBlocks(2, 3, 4)
+// 	expected = []int{8, 8, 6, 6, 0, 3, 1, 0, 3, 3, 2, 2, 0}
+// 	err = checkStatus(t, blockPool, true, expected)
+// 	if err != nil {
+// 		return
+// 	}
+
+// 	blockPool.RemovePeer("peer2")
+// 	expected = []int{8, 8, 6, 6, 0, 3, 1, 0, 3, 2, 2, 2, 0}
+// 	err = checkStatus(t, blockPool, true, expected)
+// 	if err != nil {
+// 		return
+// 	}
+
+// 	peer1.serveBlockHashes(2, 1, 0)
+// 	expected = []int{9, 9, 6, 6, 0, 3, 1, 0, 3, 2, 2, 2, 0}
+// 	err = checkStatus(t, blockPool, true, expected)
+// 	if err != nil {
+// 		return
+// 	}
+
+// 	peer1.serveBlocks(1, 2)
+// 	expected = []int{9, 9, 7, 7, 0, 3, 1, 0, 3, 2, 2, 2, 0}
+// 	err = checkStatus(t, blockPool, true, expected)
+// 	if err != nil {
+// 		return
+// 	}
+
+// 	peer1.serveBlocks(4, 5)
+// 	expected = []int{9, 9, 8, 8, 0, 3, 1, 0, 3, 2, 2, 2, 0}
+// 	err = checkStatus(t, blockPool, true, expected)
+// 	if err != nil {
+// 		return
+// 	}
+
+// 	peer3.AddPeer()
+// 	expected = []int{9, 9, 8, 8, 0, 4, 1, 0, 4, 3, 2, 3, 0}
+// 	err = checkStatus(t, blockPool, true, expected)
+// 	if err != nil {
+// 		return
+// 	}
+
+// 	peer3.serveBlocks(10, 11)
+// 	expected = []int{9, 9, 9, 9, 0, 4, 1, 0, 4, 3, 3, 3, 0}
+// 	err = checkStatus(t, blockPool, true, expected)
+// 	if err != nil {
+// 		return
+// 	}
+
+// 	peer3.serveBlockHashes(11, 10, 9)
+// 	expected = []int{11, 11, 9, 9, 0, 4, 1, 0, 4, 3, 3, 3, 0}
+// 	err = checkStatus(t, blockPool, true, expected)
+// 	if err != nil {
+// 		return
+// 	}
+
+// 	peer4.sendBlocks(11, 12)
+// 	expected = []int{11, 11, 9, 9, 0, 4, 1, 0, 4, 3, 4, 3, 1}
+// 	err = checkStatus(t, blockPool, true, expected)
+// 	if err != nil {
+// 		return
+// 	}
+// 	peer3.serveBlocks(9, 10)
+// 	expected = []int{11, 11, 10, 10, 0, 4, 1, 0, 4, 3, 4, 3, 1}
+// 	err = checkStatus(t, blockPool, true, expected)
+// 	if err != nil {
+// 		return
+// 	}
+
+// 	peer3.serveBlocks(0, 1)
+// 	blockPool.Wait(waitTimeout)
+// 	time.Sleep(200 * time.Millisecond)
+// 	expected = []int{11, 3, 11, 3, 8, 4, 1, 8, 4, 3, 4, 3, 1}
+// 	err = checkStatus(t, blockPool, false, expected)
+// 	if err != nil {
+// 		return
+// 	}
+
+// 	blockPool.Stop()
+// }
diff --git a/blockpool/test/hash_pool.go b/blockpool/test/hash_pool.go
new file mode 100644
index 000000000..4e0332d7d
--- /dev/null
+++ b/blockpool/test/hash_pool.go
@@ -0,0 +1,57 @@
+package test
+
+import (
+	"sync"
+
+	"github.com/ethereum/go-ethereum/crypto"
+)
+
+// test helpers
+// TODO: move into common test helper package (see p2p/crypto etc.)
+
+func NewHashPool() *TestHashPool {
+	return &TestHashPool{intToHash: make(intToHash), hashToInt: make(hashToInt)}
+}
+
+type intToHash map[int][]byte
+
+type hashToInt map[string]int
+
+// hashPool is a test helper, that allows random hashes to be referred to by integers
+type TestHashPool struct {
+	intToHash
+	hashToInt
+	lock sync.Mutex
+}
+
+func newHash(i int) []byte {
+	return crypto.Sha3([]byte(string(i)))
+}
+
+func (self *TestHashPool) IndexesToHashes(indexes []int) (hashes [][]byte) {
+	self.lock.Lock()
+	defer self.lock.Unlock()
+	for _, i := range indexes {
+		hash, found := self.intToHash[i]
+		if !found {
+			hash = newHash(i)
+			self.intToHash[i] = hash
+			self.hashToInt[string(hash)] = i
+		}
+		hashes = append(hashes, hash)
+	}
+	return
+}
+
+func (self *TestHashPool) HashesToIndexes(hashes [][]byte) (indexes []int) {
+	self.lock.Lock()
+	defer self.lock.Unlock()
+	for _, hash := range hashes {
+		i, found := self.hashToInt[string(hash)]
+		if !found {
+			i = -1
+		}
+		indexes = append(indexes, i)
+	}
+	return
+}
diff --git a/blockpool/test/logger.go b/blockpool/test/logger.go
new file mode 100644
index 000000000..8b776e0b5
--- /dev/null
+++ b/blockpool/test/logger.go
@@ -0,0 +1,78 @@
+package test
+
+import (
+	"log"
+	"os"
+	"sync"
+	"testing"
+
+	"github.com/ethereum/go-ethereum/logger"
+)
+
+var once sync.Once
+
+/* usage:
+func TestFunc(t *testing.T) {
+    test.LogInit()
+    // test
+}
+*/
+func LogInit() {
+	once.Do(func() {
+		var logsys = logger.NewStdLogSystem(os.Stdout, log.LstdFlags, logger.LogLevel(logger.DebugDetailLevel))
+		logger.AddLogSystem(logsys)
+	})
+}
+
+type testLogger struct{ t *testing.T }
+
+/* usage:
+func TestFunc(t *testing.T) {
+    defer test.Testlog.Detach()
+    // test
+}
+*/
+func Testlog(t *testing.T) testLogger {
+	logger.Reset()
+	l := testLogger{t}
+	logger.AddLogSystem(l)
+	return l
+}
+
+func (testLogger) GetLogLevel() logger.LogLevel { return logger.DebugLevel }
+func (testLogger) SetLogLevel(logger.LogLevel)  {}
+
+func (l testLogger) LogPrint(level logger.LogLevel, msg string) {
+	l.t.Logf("%s", msg)
+}
+
+func (testLogger) Detach() {
+	logger.Flush()
+	logger.Reset()
+}
+
+type benchLogger struct{ b *testing.B }
+
+/* usage:
+func BenchmarkFunc(b *testing.B) {
+    defer test.Benchlog.Detach()
+    // test
+}
+*/
+func Benchlog(b *testing.B) benchLogger {
+	logger.Reset()
+	l := benchLogger{b}
+	logger.AddLogSystem(l)
+	return l
+}
+
+func (benchLogger) GetLogLevel() logger.LogLevel { return logger.Silence }
+
+func (benchLogger) SetLogLevel(logger.LogLevel) {}
+func (l benchLogger) LogPrint(level logger.LogLevel, msg string) {
+	l.b.Logf("%s", msg)
+}
+func (benchLogger) Detach() {
+	logger.Flush()
+	logger.Reset()
+}
diff --git a/blockpool/test/util.go b/blockpool/test/util.go
new file mode 100644
index 000000000..e183bf1d1
--- /dev/null
+++ b/blockpool/test/util.go
@@ -0,0 +1,35 @@
+package test
+
+import (
+	"fmt"
+	"testing"
+	"time"
+)
+
+func CheckInt(name string, got int, expected int, t *testing.T) (err error) {
+	if got != expected {
+		t.Errorf("status for %v incorrect. expected %v, got %v", name, expected, got)
+		err = fmt.Errorf("")
+	}
+	return
+}
+
+func CheckDuration(name string, got time.Duration, expected time.Duration, t *testing.T) (err error) {
+	if got != expected {
+		t.Errorf("status for %v incorrect. expected %v, got %v", name, expected, got)
+		err = fmt.Errorf("")
+	}
+	return
+}
+
+func ArrayEq(a, b []int) bool {
+	if len(a) != len(b) {
+		return false
+	}
+	for i := range a {
+		if a[i] != b[i] {
+			return false
+		}
+	}
+	return true
+}
diff --git a/errs/errors.go b/errs/errors.go
new file mode 100644
index 000000000..f1b0ebdbb
--- /dev/null
+++ b/errs/errors.go
@@ -0,0 +1,91 @@
+package errs
+
+import (
+	"fmt"
+
+	"github.com/ethereum/go-ethereum/logger"
+)
+
+/*
+Errors implements an error handler providing standardised errors for a package.
+Fields:
+
+ Errors:
+  a map from error codes to description
+
+ Package:
+  name of the package/component
+
+ Level:
+  a function mapping error code to logger.LogLevel (severity)
+  if not given, errors default to logger.InfoLevel
+*/
+type Errors struct {
+	Errors  map[int]string
+	Package string
+	Level   func(code int) logger.LogLevel
+}
+
+/*
+Error implements the standard go error interface.
+
+  errors.New(code, format, params ...interface{})
+
+Prints as:
+
+ [package] description: details
+
+where details is fmt.Sprintf(self.format, self.params...)
+*/
+type Error struct {
+	Code    int
+	Name    string
+	Package string
+	level   logger.LogLevel
+	message string
+	format  string
+	params  []interface{}
+}
+
+func (self *Errors) New(code int, format string, params ...interface{}) *Error {
+	name, ok := self.Errors[code]
+	if !ok {
+		panic("invalid error code")
+	}
+	level := logger.InfoLevel
+	if self.Level != nil {
+		level = self.Level(code)
+	}
+	return &Error{
+		Code:    code,
+		Name:    name,
+		Package: self.Package,
+		level:   level,
+		format:  format,
+		params:  params,
+	}
+}
+
+func (self Error) Error() (message string) {
+	if len(message) == 0 {
+		self.message = fmt.Sprintf("[%s] %s", self.Package, self.Name)
+		if self.format != "" {
+			self.message += ": " + fmt.Sprintf(self.format, self.params...)
+		}
+	}
+	return self.message
+}
+
+func (self Error) Log(log *logger.Logger) {
+	log.Sendln(self.level, self)
+}
+
+/*
+err.Fatal() is true if err's severity level is 0 or 1 (logger.ErrorLevel or logger.Silence)
+*/
+func (self *Error) Fatal() (fatal bool) {
+	if self.level < logger.WarnLevel {
+		fatal = true
+	}
+	return
+}
diff --git a/errs/errors_test.go b/errs/errors_test.go
new file mode 100644
index 000000000..09f70eef5
--- /dev/null
+++ b/errs/errors_test.go
@@ -0,0 +1,46 @@
+package errs
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/ethereum/go-ethereum/logger"
+)
+
+func testErrors() *Errors {
+	return &Errors{
+		Package: "TEST",
+		Errors: map[int]string{
+			0: "zero",
+			1: "one",
+		},
+		Level: func(i int) (l logger.LogLevel) {
+			if i == 0 {
+				l = logger.ErrorLevel
+			} else {
+				l = logger.WarnLevel
+			}
+			return
+		},
+	}
+}
+
+func TestErrorMessage(t *testing.T) {
+	err := testErrors().New(0, "zero detail %v", "available")
+	message := fmt.Sprintf("%v", err)
+	exp := "[TEST] zero: zero detail available"
+	if message != exp {
+		t.Errorf("error message incorrect. expected %v, got %v", exp, message)
+	}
+}
+
+func TestErrorSeverity(t *testing.T) {
+	err0 := testErrors().New(0, "zero detail")
+	if !err0.Fatal() {
+		t.Errorf("error should be fatal")
+	}
+	err1 := testErrors().New(1, "one detail")
+	if err1.Fatal() {
+		t.Errorf("error should not be fatal")
+	}
+}
diff --git a/eth/backend.go b/eth/backend.go
index 0e5d24429..f6cde5ccd 100644
--- a/eth/backend.go
+++ b/eth/backend.go
@@ -7,6 +7,7 @@ import (
 	"path"
 	"strings"
 
+	"github.com/ethereum/go-ethereum/blockpool"
 	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/ethdb"
@@ -117,7 +118,7 @@ type Ethereum struct {
 	blockProcessor *core.BlockProcessor
 	txPool         *core.TxPool
 	chainManager   *core.ChainManager
-	blockPool      *BlockPool
+	blockPool      *blockpool.BlockPool
 	whisper        *whisper.Whisper
 
 	net      *p2p.Server
@@ -185,7 +186,7 @@ func New(config *Config) (*Ethereum, error) {
 
 	hasBlock := eth.chainManager.HasBlock
 	insertChain := eth.chainManager.InsertChain
-	eth.blockPool = NewBlockPool(hasBlock, insertChain, ezp.Verify)
+	eth.blockPool = blockpool.New(hasBlock, insertChain, ezp.Verify)
 
 	netprv, err := config.nodeKey()
 	if err != nil {
@@ -220,7 +221,7 @@ func (s *Ethereum) Name() string                         { return s.net.Name }
 func (s *Ethereum) ChainManager() *core.ChainManager     { return s.chainManager }
 func (s *Ethereum) BlockProcessor() *core.BlockProcessor { return s.blockProcessor }
 func (s *Ethereum) TxPool() *core.TxPool                 { return s.txPool }
-func (s *Ethereum) BlockPool() *BlockPool                { return s.blockPool }
+func (s *Ethereum) BlockPool() *blockpool.BlockPool      { return s.blockPool }
 func (s *Ethereum) Whisper() *whisper.Whisper            { return s.whisper }
 func (s *Ethereum) EventMux() *event.TypeMux             { return s.eventMux }
 func (s *Ethereum) Db() ethutil.Database                 { return s.db }
diff --git a/eth/block_pool.go b/eth/block_pool.go
deleted file mode 100644
index 13016c694..000000000
--- a/eth/block_pool.go
+++ /dev/null
@@ -1,1239 +0,0 @@
-package eth
-
-import (
-	"bytes"
-	"fmt"
-	"math"
-	"math/big"
-	"math/rand"
-	"sort"
-	"sync"
-	"time"
-
-	"github.com/ethereum/go-ethereum/core/types"
-	"github.com/ethereum/go-ethereum/ethutil"
-	ethlogger "github.com/ethereum/go-ethereum/logger"
-	"github.com/ethereum/go-ethereum/pow"
-)
-
-var poolLogger = ethlogger.NewLogger("Blockpool")
-
-const (
-	blockHashesBatchSize       = 256
-	blockBatchSize             = 64
-	blocksRequestInterval      = 500 // ms
-	blocksRequestRepetition    = 1
-	blockHashesRequestInterval = 500 // ms
-	blocksRequestMaxIdleRounds = 100
-	blockHashesTimeout         = 60  // seconds
-	blocksTimeout              = 120 // seconds
-)
-
-type poolNode struct {
-	lock    sync.RWMutex
-	hash    []byte
-	td      *big.Int
-	block   *types.Block
-	parent  *poolNode
-	peer    string
-	blockBy string
-}
-
-type poolEntry struct {
-	node    *poolNode
-	section *section
-	index   int
-}
-
-type BlockPool struct {
-	lock      sync.RWMutex
-	chainLock sync.RWMutex
-
-	pool map[string]*poolEntry
-
-	peersLock sync.RWMutex
-	peers     map[string]*peerInfo
-	peer      *peerInfo
-
-	quit    chan bool
-	purgeC  chan bool
-	flushC  chan bool
-	wg      sync.WaitGroup
-	procWg  sync.WaitGroup
-	running bool
-
-	// the minimal interface with blockchain
-	hasBlock    func(hash []byte) bool
-	insertChain func(types.Blocks) error
-	verifyPoW   func(pow.Block) bool
-}
-
-type peerInfo struct {
-	lock sync.RWMutex
-
-	td               *big.Int
-	currentBlockHash []byte
-	currentBlock     *types.Block
-	currentBlockC    chan *types.Block
-	parentHash       []byte
-	headSection      *section
-	headSectionC     chan *section
-	id               string
-
-	requestBlockHashes func([]byte) error
-	requestBlocks      func([][]byte) error
-	peerError          func(int, string, ...interface{})
-
-	sections map[string]*section
-
-	quitC chan bool
-}
-
-// structure to store long range links on chain to skip along
-type section struct {
-	lock        sync.RWMutex
-	parent      *section
-	child       *section
-	top         *poolNode
-	bottom      *poolNode
-	nodes       []*poolNode
-	controlC    chan *peerInfo
-	suicideC    chan bool
-	blockChainC chan bool
-	forkC       chan chan bool
-	offC        chan bool
-}
-
-func NewBlockPool(hasBlock func(hash []byte) bool, insertChain func(types.Blocks) error, verifyPoW func(pow.Block) bool,
-) *BlockPool {
-	return &BlockPool{
-		hasBlock:    hasBlock,
-		insertChain: insertChain,
-		verifyPoW:   verifyPoW,
-	}
-}
-
-// allows restart
-func (self *BlockPool) Start() {
-	self.lock.Lock()
-	if self.running {
-		self.lock.Unlock()
-		return
-	}
-	self.running = true
-	self.quit = make(chan bool)
-	self.flushC = make(chan bool)
-	self.pool = make(map[string]*poolEntry)
-
-	self.lock.Unlock()
-
-	self.peersLock.Lock()
-	self.peers = make(map[string]*peerInfo)
-	self.peersLock.Unlock()
-
-	poolLogger.Infoln("Started")
-
-}
-
-func (self *BlockPool) Stop() {
-	self.lock.Lock()
-	if !self.running {
-		self.lock.Unlock()
-		return
-	}
-	self.running = false
-
-	self.lock.Unlock()
-
-	poolLogger.Infoln("Stopping...")
-
-	close(self.quit)
-	//self.wg.Wait()
-
-	self.peersLock.Lock()
-	self.peers = nil
-	self.peer = nil
-	self.peersLock.Unlock()
-
-	self.lock.Lock()
-	self.pool = nil
-	self.lock.Unlock()
-
-	poolLogger.Infoln("Stopped")
-}
-
-func (self *BlockPool) Purge() {
-	self.lock.Lock()
-	if !self.running {
-		self.lock.Unlock()
-		return
-	}
-	self.lock.Unlock()
-
-	poolLogger.Infoln("Purging...")
-
-	close(self.purgeC)
-	self.wg.Wait()
-
-	self.purgeC = make(chan bool)
-
-	poolLogger.Infoln("Stopped")
-
-}
-
-func (self *BlockPool) Wait(t time.Duration) {
-	self.lock.Lock()
-	if !self.running {
-		self.lock.Unlock()
-		return
-	}
-	self.lock.Unlock()
-
-	poolLogger.Infoln("Waiting for processes to complete...")
-	close(self.flushC)
-	w := make(chan bool)
-	go func() {
-		self.procWg.Wait()
-		close(w)
-	}()
-
-	select {
-	case <-w:
-		poolLogger.Infoln("Processes complete")
-	case <-time.After(t):
-		poolLogger.Warnf("Timeout")
-	}
-	self.flushC = make(chan bool)
-}
-
-// AddPeer is called by the eth protocol instance running on the peer after
-// the status message has been received with total difficulty and current block hash
-// AddPeer can only be used once, RemovePeer needs to be called when the peer disconnects
-func (self *BlockPool) AddPeer(td *big.Int, currentBlockHash []byte, peerId string, requestBlockHashes func([]byte) error, requestBlocks func([][]byte) error, peerError func(int, string, ...interface{})) (best bool) {
-
-	self.peersLock.Lock()
-	defer self.peersLock.Unlock()
-	peer, ok := self.peers[peerId]
-	if ok {
-		if bytes.Compare(peer.currentBlockHash, currentBlockHash) != 0 {
-			poolLogger.Debugf("Update peer %v with td %v and current block %s", peerId, td, name(currentBlockHash))
-			peer.lock.Lock()
-			peer.td = td
-			peer.currentBlockHash = currentBlockHash
-			peer.currentBlock = nil
-			peer.parentHash = nil
-			peer.headSection = nil
-			peer.lock.Unlock()
-		}
-	} else {
-		peer = &peerInfo{
-			td:                 td,
-			currentBlockHash:   currentBlockHash,
-			id:                 peerId, //peer.Identity().Pubkey()
-			requestBlockHashes: requestBlockHashes,
-			requestBlocks:      requestBlocks,
-			peerError:          peerError,
-			sections:           make(map[string]*section),
-			currentBlockC:      make(chan *types.Block),
-			headSectionC:       make(chan *section),
-		}
-		self.peers[peerId] = peer
-		poolLogger.Debugf("add new peer %v with td %v and current block %x", peerId, td, currentBlockHash[:4])
-	}
-	// check peer current head
-	if self.hasBlock(currentBlockHash) {
-		// peer not ahead
-		return false
-	}
-
-	if self.peer == peer {
-		// new block update
-		// peer is already active best peer, request hashes
-		poolLogger.Debugf("[%s] already the best peer. Request new head section info from %s", peerId, name(currentBlockHash))
-		peer.headSectionC <- nil
-		best = true
-	} else {
-		currentTD := ethutil.Big0
-		if self.peer != nil {
-			currentTD = self.peer.td
-		}
-		if td.Cmp(currentTD) > 0 {
-			poolLogger.Debugf("peer %v promoted best peer", peerId)
-			self.switchPeer(self.peer, peer)
-			self.peer = peer
-			best = true
-		}
-	}
-	return
-}
-
-func (self *BlockPool) requestHeadSection(peer *peerInfo) {
-	self.wg.Add(1)
-	self.procWg.Add(1)
-	poolLogger.Debugf("[%s] head section at [%s] requesting info", peer.id, name(peer.currentBlockHash))
-
-	go func() {
-		var idle bool
-		peer.lock.RLock()
-		quitC := peer.quitC
-		currentBlockHash := peer.currentBlockHash
-		peer.lock.RUnlock()
-		blockHashesRequestTimer := time.NewTimer(0)
-		blocksRequestTimer := time.NewTimer(0)
-		suicide := time.NewTimer(blockHashesTimeout * time.Second)
-		blockHashesRequestTimer.Stop()
-		defer blockHashesRequestTimer.Stop()
-		defer blocksRequestTimer.Stop()
-
-		entry := self.get(currentBlockHash)
-		if entry != nil {
-			entry.node.lock.RLock()
-			currentBlock := entry.node.block
-			entry.node.lock.RUnlock()
-			if currentBlock != nil {
-				peer.lock.Lock()
-				peer.currentBlock = currentBlock
-				peer.parentHash = currentBlock.ParentHash()
-				poolLogger.Debugf("[%s] head block [%s] found", peer.id, name(currentBlockHash))
-				peer.lock.Unlock()
-				blockHashesRequestTimer.Reset(0)
-				blocksRequestTimer.Stop()
-			}
-		}
-
-	LOOP:
-		for {
-
-			select {
-			case <-self.quit:
-				break LOOP
-
-			case <-quitC:
-				poolLogger.Debugf("[%s] head section at [%s] incomplete - quit request loop", peer.id, name(currentBlockHash))
-				break LOOP
-
-			case headSection := <-peer.headSectionC:
-				peer.lock.Lock()
-				peer.headSection = headSection
-				if headSection == nil {
-					oldBlockHash := currentBlockHash
-					currentBlockHash = peer.currentBlockHash
-					poolLogger.Debugf("[%s] head section changed [%s] -> [%s]", peer.id, name(oldBlockHash), name(currentBlockHash))
-					if idle {
-						idle = false
-						suicide.Reset(blockHashesTimeout * time.Second)
-						self.procWg.Add(1)
-					}
-					blocksRequestTimer.Reset(blocksRequestInterval * time.Millisecond)
-				} else {
-					poolLogger.DebugDetailf("[%s] head section at [%s] created", peer.id, name(currentBlockHash))
-					if !idle {
-						idle = true
-						suicide.Stop()
-						self.procWg.Done()
-					}
-				}
-				peer.lock.Unlock()
-				blockHashesRequestTimer.Stop()
-
-			case <-blockHashesRequestTimer.C:
-				poolLogger.DebugDetailf("[%s] head section at [%s] not found, requesting block hashes", peer.id, name(currentBlockHash))
-				peer.requestBlockHashes(currentBlockHash)
-				blockHashesRequestTimer.Reset(blockHashesRequestInterval * time.Millisecond)
-
-			case currentBlock := <-peer.currentBlockC:
-				peer.lock.Lock()
-				peer.currentBlock = currentBlock
-				peer.parentHash = currentBlock.ParentHash()
-				poolLogger.DebugDetailf("[%s] head block [%s] found", peer.id, name(currentBlockHash))
-				peer.lock.Unlock()
-				if self.hasBlock(currentBlock.ParentHash()) {
-					if err := self.insertChain(types.Blocks([]*types.Block{currentBlock})); err != nil {
-						peer.peerError(ErrInvalidBlock, "%v", err)
-					}
-					if !idle {
-						idle = true
-						suicide.Stop()
-						self.procWg.Done()
-					}
-				} else {
-					blockHashesRequestTimer.Reset(0)
-				}
-				blocksRequestTimer.Stop()
-
-			case <-blocksRequestTimer.C:
-				peer.lock.RLock()
-				poolLogger.DebugDetailf("[%s] head block [%s] not found, requesting", peer.id, name(currentBlockHash))
-				peer.requestBlocks([][]byte{peer.currentBlockHash})
-				peer.lock.RUnlock()
-				blocksRequestTimer.Reset(blocksRequestInterval * time.Millisecond)
-
-			case <-suicide.C:
-				peer.peerError(ErrInsufficientChainInfo, "peer failed to provide block hashes or head block for block hash %x", currentBlockHash)
-				break LOOP
-			}
-		}
-		self.wg.Done()
-		if !idle {
-			self.procWg.Done()
-		}
-	}()
-}
-
-// RemovePeer is called by the eth protocol when the peer disconnects
-func (self *BlockPool) RemovePeer(peerId string) {
-	self.peersLock.Lock()
-	defer self.peersLock.Unlock()
-	peer, ok := self.peers[peerId]
-	if !ok {
-		return
-	}
-	delete(self.peers, peerId)
-	poolLogger.Debugf("remove peer %v", peerId)
-
-	// if current best peer is removed, need find a better one
-	if self.peer == peer {
-		var newPeer *peerInfo
-		max := ethutil.Big0
-		// peer with the highest self-acclaimed TD is chosen
-		for _, info := range self.peers {
-			if info.td.Cmp(max) > 0 {
-				max = info.td
-				newPeer = info
-			}
-		}
-		if newPeer != nil {
-			poolLogger.Debugf("peer %v with td %v promoted to best peer", newPeer.id, newPeer.td)
-		} else {
-			poolLogger.Warnln("no peers")
-		}
-		self.peer = newPeer
-		self.switchPeer(peer, newPeer)
-	}
-}
-
-// Entry point for eth protocol to add block hashes received via BlockHashesMsg
-// only hashes from the best peer is handled
-// this method is always responsible to initiate further hash requests until
-// a known parent is reached unless cancelled by a peerChange event
-// this process also launches all request processes on each chain section
-// this function needs to run asynchronously for one peer since the message is discarded???
-func (self *BlockPool) AddBlockHashes(next func() ([]byte, bool), peerId string) {
-
-	// register with peer manager loop
-
-	peer, best := self.getPeer(peerId)
-	if !best {
-		return
-	}
-	// peer is still the best
-
-	var size, n int
-	var hash []byte
-	var ok, headSection bool
-	var sec, child, parent *section
-	var entry *poolEntry
-	var nodes []*poolNode
-	bestPeer := peer
-
-	hash, ok = next()
-	peer.lock.Lock()
-	if bytes.Compare(peer.parentHash, hash) == 0 {
-		if self.hasBlock(peer.currentBlockHash) {
-			return
-		}
-		poolLogger.Debugf("adding hashes at chain head for best peer %s starting from [%s]", peerId, name(peer.currentBlockHash))
-		headSection = true
-
-		if entry := self.get(peer.currentBlockHash); entry == nil {
-			node := &poolNode{
-				hash:    peer.currentBlockHash,
-				block:   peer.currentBlock,
-				peer:    peerId,
-				blockBy: peerId,
-			}
-			if size == 0 {
-				sec = newSection()
-			}
-			nodes = append(nodes, node)
-			size++
-			n++
-		} else {
-			child = entry.section
-		}
-	} else {
-		poolLogger.Debugf("adding hashes for best peer %s starting from [%s]", peerId, name(hash))
-	}
-	quitC := peer.quitC
-	peer.lock.Unlock()
-
-LOOP:
-	// iterate using next (rlp stream lazy decoder) feeding hashesC
-	for ; ok; hash, ok = next() {
-		n++
-		select {
-		case <-self.quit:
-			return
-		case <-quitC:
-			// if the peer is demoted, no more hashes taken
-			bestPeer = nil
-			break LOOP
-		default:
-		}
-		if self.hasBlock(hash) {
-			// check if known block connecting the downloaded chain to our blockchain
-			poolLogger.DebugDetailf("[%s] known block", name(hash))
-			// mark child as absolute pool root with parent known to blockchain
-			if sec != nil {
-				self.connectToBlockChain(sec)
-			} else {
-				if child != nil {
-					self.connectToBlockChain(child)
-				}
-			}
-			break LOOP
-		}
-		// look up node in pool
-		entry = self.get(hash)
-		if entry != nil {
-			// reached a known chain in the pool
-			if entry.node == entry.section.bottom && n == 1 {
-				// the first block hash received is an orphan in the pool, so rejoice and continue
-				poolLogger.DebugDetailf("[%s] connecting child section", sectionName(entry.section))
-				child = entry.section
-				continue LOOP
-			}
-			poolLogger.DebugDetailf("[%s] reached blockpool chain", name(hash))
-			parent = entry.section
-			break LOOP
-		}
-		// if node for block hash does not exist, create it and index in the pool
-		node := &poolNode{
-			hash: hash,
-			peer: peerId,
-		}
-		if size == 0 {
-			sec = newSection()
-		}
-		nodes = append(nodes, node)
-		size++
-	} //for
-
-	self.chainLock.Lock()
-
-	poolLogger.DebugDetailf("added %v hashes sent by %s", n, peerId)
-
-	if parent != nil && entry != nil && entry.node != parent.top {
-		poolLogger.DebugDetailf("[%s] split section at fork", sectionName(parent))
-		parent.controlC <- nil
-		waiter := make(chan bool)
-		parent.forkC <- waiter
-		chain := parent.nodes
-		parent.nodes = chain[entry.index:]
-		parent.top = parent.nodes[0]
-		orphan := newSection()
-		self.link(orphan, parent.child)
-		self.processSection(orphan, chain[0:entry.index])
-		orphan.controlC <- nil
-		close(waiter)
-	}
-
-	if size > 0 {
-		self.processSection(sec, nodes)
-		poolLogger.DebugDetailf("[%s]->[%s](%v)->[%s] new chain section", sectionName(parent), sectionName(sec), size, sectionName(child))
-		self.link(parent, sec)
-		self.link(sec, child)
-	} else {
-		poolLogger.DebugDetailf("[%s]->[%s] connecting known sections", sectionName(parent), sectionName(child))
-		self.link(parent, child)
-	}
-
-	self.chainLock.Unlock()
-
-	if parent != nil && bestPeer != nil {
-		self.activateChain(parent, peer)
-		poolLogger.Debugf("[%s] activate parent section [%s]", name(parent.top.hash), sectionName(parent))
-	}
-
-	if sec != nil {
-		peer.addSection(sec.top.hash, sec)
-		// request next section here once, only repeat if bottom block arrives,
-		// otherwise no way to check if it arrived
-		peer.requestBlockHashes(sec.bottom.hash)
-		sec.controlC <- bestPeer
-		poolLogger.Debugf("[%s] activate new section", sectionName(sec))
-	}
-
-	if headSection {
-		var headSec *section
-		switch {
-		case sec != nil:
-			headSec = sec
-		case child != nil:
-			headSec = child
-		default:
-			headSec = parent
-		}
-		peer.headSectionC <- headSec
-	}
-}
-
-func name(hash []byte) (name string) {
-	if hash == nil {
-		name = ""
-	} else {
-		name = fmt.Sprintf("%x", hash[:4])
-	}
-	return
-}
-
-func sectionName(section *section) (name string) {
-	if section == nil {
-		name = ""
-	} else {
-		name = fmt.Sprintf("%x-%x", section.bottom.hash[:4], section.top.hash[:4])
-	}
-	return
-}
-
-// AddBlock is the entry point for the eth protocol when blockmsg is received upon requests
-// It has a strict interpretation of the protocol in that if the block received has not been requested, it results in an error (which can be ignored)
-// block is checked for PoW
-// only the first PoW-valid block for a hash is considered legit
-func (self *BlockPool) AddBlock(block *types.Block, peerId string) {
-	hash := block.Hash()
-	self.peersLock.Lock()
-	peer := self.peer
-	self.peersLock.Unlock()
-
-	entry := self.get(hash)
-	if bytes.Compare(hash, peer.currentBlockHash) == 0 {
-		poolLogger.Debugf("add head block [%s] for peer %s", name(hash), peerId)
-		peer.currentBlockC <- block
-	} else {
-		if entry == nil {
-			poolLogger.Warnf("unrequested block [%s] by peer %s", name(hash), peerId)
-			self.peerError(peerId, ErrUnrequestedBlock, "%x", hash)
-		}
-	}
-	if entry == nil {
-		return
-	}
-
-	node := entry.node
-	node.lock.Lock()
-	defer node.lock.Unlock()
-
-	// check if block already present
-	if node.block != nil {
-		poolLogger.DebugDetailf("block [%s] already sent by %s", name(hash), node.blockBy)
-		return
-	}
-
-	if self.hasBlock(hash) {
-		poolLogger.DebugDetailf("block [%s] already known", name(hash))
-	} else {
-
-		// validate block for PoW
-		if !self.verifyPoW(block) {
-			poolLogger.Warnf("invalid pow on block [%s %v] by peer %s", name(hash), block.Number(), peerId)
-			self.peerError(peerId, ErrInvalidPoW, "%x", hash)
-			return
-		}
-	}
-	poolLogger.DebugDetailf("added block [%s] sent by peer %s", name(hash), peerId)
-	node.block = block
-	node.blockBy = peerId
-
-}
-
-func (self *BlockPool) connectToBlockChain(section *section) {
-	select {
-	case <-section.offC:
-		self.addSectionToBlockChain(section)
-	case <-section.blockChainC:
-	default:
-		close(section.blockChainC)
-	}
-}
-
-func (self *BlockPool) addSectionToBlockChain(section *section) (rest int, err error) {
-
-	var blocks types.Blocks
-	var node *poolNode
-	var keys []string
-	rest = len(section.nodes)
-	for rest > 0 {
-		rest--
-		node = section.nodes[rest]
-		node.lock.RLock()
-		block := node.block
-		node.lock.RUnlock()
-		if block == nil {
-			break
-		}
-		keys = append(keys, string(node.hash))
-		blocks = append(blocks, block)
-	}
-
-	self.lock.Lock()
-	for _, key := range keys {
-		delete(self.pool, key)
-	}
-	self.lock.Unlock()
-
-	poolLogger.Infof("insert %v blocks into blockchain", len(blocks))
-	err = self.insertChain(blocks)
-	if err != nil {
-		// TODO: not clear which peer we need to address
-		// peerError should dispatch to peer if still connected and disconnect
-		self.peerError(node.blockBy, ErrInvalidBlock, "%v", err)
-		poolLogger.Warnf("invalid block %x", node.hash)
-		poolLogger.Warnf("penalise peers %v (hash), %v (block)", node.peer, node.blockBy)
-		// penalise peer in node.blockBy
-		// self.disconnect()
-	}
-	return
-}
-
-func (self *BlockPool) activateChain(section *section, peer *peerInfo) {
-	poolLogger.DebugDetailf("[%s] activate known chain for peer %s", sectionName(section), peer.id)
-	i := 0
-LOOP:
-	for section != nil {
-		// register this section with the peer and quit if registered
-		poolLogger.DebugDetailf("[%s] register section with peer %s", sectionName(section), peer.id)
-		if peer.addSection(section.top.hash, section) == section {
-			return
-		}
-		poolLogger.DebugDetailf("[%s] activate section process", sectionName(section))
-		select {
-		case section.controlC <- peer:
-		case <-section.offC:
-		}
-		i++
-		section = self.getParent(section)
-		select {
-		case <-peer.quitC:
-			break LOOP
-		case <-self.quit:
-			break LOOP
-		default:
-		}
-	}
-}
-
-// main worker thread on each section in the poolchain
-// - kills the section if there are blocks missing after an absolute time
-// - kills the section if there are maxIdleRounds of idle rounds of block requests with no response
-// - periodically polls the chain section for missing blocks which are then requested from peers
-// - registers the process controller on the peer so that if the peer is promoted as best peer the second time (after a disconnect of a better one), all active processes are switched back on unless they expire and killed ()
-// - when turned off (if peer disconnects and new peer connects with alternative chain), no blockrequests are made but absolute expiry timer is ticking
-// - when turned back on it recursively calls itself on the root of the next chain section
-// - when exits, signals to
-func (self *BlockPool) processSection(sec *section, nodes []*poolNode) {
-
-	for i, node := range nodes {
-		entry := &poolEntry{node: node, section: sec, index: i}
-		self.set(node.hash, entry)
-	}
-
-	sec.bottom = nodes[len(nodes)-1]
-	sec.top = nodes[0]
-	sec.nodes = nodes
-	poolLogger.DebugDetailf("[%s] setup section process", sectionName(sec))
-
-	self.wg.Add(1)
-	go func() {
-
-		// absolute time after which sub-chain is killed if not complete (some blocks are missing)
-		suicideTimer := time.After(blocksTimeout * time.Second)
-
-		var peer, newPeer *peerInfo
-
-		var blocksRequestTimer, blockHashesRequestTimer <-chan time.Time
-		var blocksRequestTime, blockHashesRequestTime bool
-		var blocksRequests, blockHashesRequests int
-		var blocksRequestsComplete, blockHashesRequestsComplete bool
-
-		// node channels for the section
-		var missingC, processC, offC chan *poolNode
-		// container for missing block hashes
-		var hashes [][]byte
-
-		var i, missing, lastMissing, depth int
-		var idle int
-		var init, done, same, ready bool
-		var insertChain bool
-		var quitC chan bool
-
-		var blockChainC = sec.blockChainC
-
-		var parentHash []byte
-
-	LOOP:
-		for {
-
-			if insertChain {
-				insertChain = false
-				rest, err := self.addSectionToBlockChain(sec)
-				if err != nil {
-					close(sec.suicideC)
-					continue LOOP
-				}
-				if rest == 0 {
-					blocksRequestsComplete = true
-					child := self.getChild(sec)
-					if child != nil {
-						self.connectToBlockChain(child)
-					}
-				}
-			}
-
-			if blockHashesRequestsComplete && blocksRequestsComplete {
-				// not waiting for hashes any more
-				poolLogger.Debugf("[%s] section complete %v blocks retrieved (%v attempts), hash requests complete on root (%v attempts)", sectionName(sec), depth, blocksRequests, blockHashesRequests)
-				break LOOP
-			} // otherwise suicide if no hashes coming
-
-			if done {
-				// went through all blocks in section
-				if missing == 0 {
-					// no missing blocks
-					poolLogger.DebugDetailf("[%s] got all blocks. process complete (%v total blocksRequests): missing %v/%v/%v", sectionName(sec), blocksRequests, missing, lastMissing, depth)
-					blocksRequestsComplete = true
-					blocksRequestTimer = nil
-					blocksRequestTime = false
-				} else {
-					poolLogger.DebugDetailf("[%s] section checked: missing %v/%v/%v", sectionName(sec), missing, lastMissing, depth)
-					// some missing blocks
-					blocksRequests++
-					if len(hashes) > 0 {
-						// send block requests to peers
-						self.requestBlocks(blocksRequests, hashes)
-						hashes = nil
-					}
-					if missing == lastMissing {
-						// idle round
-						if same {
-							// more than once
-							idle++
-							// too many idle rounds
-							if idle >= blocksRequestMaxIdleRounds {
-								poolLogger.DebugDetailf("[%s] block requests had %v idle rounds (%v total attempts): missing %v/%v/%v\ngiving up...", sectionName(sec), idle, blocksRequests, missing, lastMissing, depth)
-								close(sec.suicideC)
-							}
-						} else {
-							idle = 0
-						}
-						same = true
-					} else {
-						same = false
-					}
-				}
-				lastMissing = missing
-				ready = true
-				done = false
-				// save a new processC (blocks still missing)
-				offC = missingC
-				missingC = processC
-				// put processC offline
-				processC = nil
-			}
-			//
-
-			if ready && blocksRequestTime && !blocksRequestsComplete {
-				poolLogger.DebugDetailf("[%s] check if new blocks arrived (attempt %v): missing %v/%v/%v", sectionName(sec), blocksRequests, missing, lastMissing, depth)
-				blocksRequestTimer = time.After(blocksRequestInterval * time.Millisecond)
-				blocksRequestTime = false
-				processC = offC
-			}
-
-			if blockHashesRequestTime {
-				var parentSection = self.getParent(sec)
-				if parentSection == nil {
-					if parent := self.get(parentHash); parent != nil {
-						parentSection = parent.section
-						self.chainLock.Lock()
-						self.link(parentSection, sec)
-						self.chainLock.Unlock()
-					} else {
-						if self.hasBlock(parentHash) {
-							insertChain = true
-							blockHashesRequestTime = false
-							blockHashesRequestTimer = nil
-							blockHashesRequestsComplete = true
-							continue LOOP
-						}
-					}
-				}
-				if parentSection != nil {
-					// if not root of chain, switch off
-					poolLogger.DebugDetailf("[%s] parent found, hash requests deactivated (after %v total attempts)\n", sectionName(sec), blockHashesRequests)
-					blockHashesRequestTimer = nil
-					blockHashesRequestsComplete = true
-				} else {
-					blockHashesRequests++
-					poolLogger.Debugf("[%s] hash request on root (%v total attempts)\n", sectionName(sec), blockHashesRequests)
-					peer.requestBlockHashes(sec.bottom.hash)
-					blockHashesRequestTimer = time.After(blockHashesRequestInterval * time.Millisecond)
-				}
-				blockHashesRequestTime = false
-			}
-
-			select {
-			case <-self.quit:
-				break LOOP
-
-			case <-quitC:
-				// peer quit or demoted, put section in idle mode
-				quitC = nil
-				go func() {
-					sec.controlC <- nil
-				}()
-
-			case <-self.purgeC:
-				suicideTimer = time.After(0)
-
-			case <-suicideTimer:
-				close(sec.suicideC)
-				poolLogger.Debugf("[%s] timeout. (%v total attempts): missing %v/%v/%v", sectionName(sec), blocksRequests, missing, lastMissing, depth)
-
-			case <-sec.suicideC:
-				poolLogger.Debugf("[%s] suicide", sectionName(sec))
-
-				// first delink from child and parent under chainlock
-				self.chainLock.Lock()
-				self.link(nil, sec)
-				self.link(sec, nil)
-				self.chainLock.Unlock()
-				// delete node entries from pool index under pool lock
-				self.lock.Lock()
-				for _, node := range sec.nodes {
-					delete(self.pool, string(node.hash))
-				}
-				self.lock.Unlock()
-
-				break LOOP
-
-			case <-blocksRequestTimer:
-				poolLogger.DebugDetailf("[%s] block request time", sectionName(sec))
-				blocksRequestTime = true
-
-			case <-blockHashesRequestTimer:
-				poolLogger.DebugDetailf("[%s] hash request time", sectionName(sec))
-				blockHashesRequestTime = true
-
-			case newPeer = <-sec.controlC:
-
-				// active -> idle
-				if peer != nil && newPeer == nil {
-					self.procWg.Done()
-					if init {
-						poolLogger.Debugf("[%s] idle mode (%v total attempts): missing %v/%v/%v", sectionName(sec), blocksRequests, missing, lastMissing, depth)
-					}
-					blocksRequestTime = false
-					blocksRequestTimer = nil
-					blockHashesRequestTime = false
-					blockHashesRequestTimer = nil
-					if processC != nil {
-						offC = processC
-						processC = nil
-					}
-				}
-
-				// idle -> active
-				if peer == nil && newPeer != nil {
-					self.procWg.Add(1)
-
-					poolLogger.Debugf("[%s] active mode", sectionName(sec))
-					if !blocksRequestsComplete {
-						blocksRequestTime = true
-					}
-					if !blockHashesRequestsComplete && parentHash != nil {
-						blockHashesRequestTime = true
-					}
-					if !init {
-						processC = make(chan *poolNode, blockHashesBatchSize)
-						missingC = make(chan *poolNode, blockHashesBatchSize)
-						i = 0
-						missing = 0
-						self.wg.Add(1)
-						self.procWg.Add(1)
-						depth = len(sec.nodes)
-						lastMissing = depth
-						// if not run at least once fully, launch iterator
-						go func() {
-							var node *poolNode
-						IT:
-							for _, node = range sec.nodes {
-								select {
-								case processC <- node:
-								case <-self.quit:
-									break IT
-								}
-							}
-							close(processC)
-							self.wg.Done()
-							self.procWg.Done()
-						}()
-					} else {
-						poolLogger.Debugf("[%s] restore earlier state", sectionName(sec))
-						processC = offC
-					}
-				}
-				// reset quitC to current best peer
-				if newPeer != nil {
-					quitC = newPeer.quitC
-				}
-				peer = newPeer
-
-			case waiter := <-sec.forkC:
-				// this case just blocks the process until section is split at the fork
-				<-waiter
-				init = false
-				done = false
-				ready = false
-
-			case node, ok := <-processC:
-				if !ok && !init {
-					// channel closed, first iteration finished
-					init = true
-					done = true
-					processC = make(chan *poolNode, missing)
-					poolLogger.DebugDetailf("[%s] section initalised: missing %v/%v/%v", sectionName(sec), missing, lastMissing, depth)
-					continue LOOP
-				}
-				if ready {
-					i = 0
-					missing = 0
-					ready = false
-				}
-				i++
-				// if node has no block
-				node.lock.RLock()
-				block := node.block
-				node.lock.RUnlock()
-				if block == nil {
-					missing++
-					hashes = append(hashes, node.hash)
-					if len(hashes) == blockBatchSize {
-						poolLogger.Debugf("[%s] request %v missing blocks", sectionName(sec), len(hashes))
-						self.requestBlocks(blocksRequests, hashes)
-						hashes = nil
-					}
-					missingC <- node
-				} else {
-					if i == lastMissing {
-						if blockChainC == nil {
-							insertChain = true
-						} else {
-							if parentHash == nil {
-								parentHash = block.ParentHash()
-								poolLogger.Debugf("[%s] found root block [%s]", sectionName(sec), name(parentHash))
-								blockHashesRequestTime = true
-							}
-						}
-					}
-				}
-				if i == lastMissing && init {
-					done = true
-				}
-
-			case <-blockChainC:
-				// closed blockChain channel indicates that the blockpool is reached
-				// connected to the blockchain, insert the longest chain of blocks
-				poolLogger.Debugf("[%s] reached blockchain", sectionName(sec))
-				blockChainC = nil
-				// switch off hash requests in case they were on
-				blockHashesRequestTime = false
-				blockHashesRequestTimer = nil
-				blockHashesRequestsComplete = true
-				// section root has block
-				if len(sec.nodes) > 0 && sec.nodes[len(sec.nodes)-1].block != nil {
-					insertChain = true
-				}
-				continue LOOP
-
-			} // select
-		} // for
-
-		close(sec.offC)
-
-		self.wg.Done()
-		if peer != nil {
-			self.procWg.Done()
-		}
-	}()
-	return
-}
-
-func (self *BlockPool) peerError(peerId string, code int, format string, params ...interface{}) {
-	self.peersLock.RLock()
-	defer self.peersLock.RUnlock()
-	peer, ok := self.peers[peerId]
-	if ok {
-		peer.peerError(code, format, params...)
-	}
-}
-
-func (self *BlockPool) requestBlocks(attempts int, hashes [][]byte) {
-	self.wg.Add(1)
-	self.procWg.Add(1)
-	go func() {
-		// distribute block request among known peers
-		self.peersLock.Lock()
-		defer self.peersLock.Unlock()
-		peerCount := len(self.peers)
-		// on first attempt use the best peer
-		if attempts == 0 {
-			poolLogger.Debugf("request %v missing blocks from best peer %s", len(hashes), self.peer.id)
-			self.peer.requestBlocks(hashes)
-			return
-		}
-		repetitions := int(math.Min(float64(peerCount), float64(blocksRequestRepetition)))
-		i := 0
-		indexes := rand.Perm(peerCount)[0:repetitions]
-		sort.Ints(indexes)
-		poolLogger.Debugf("request %v missing blocks from %v/%v peers: chosen %v", len(hashes), repetitions, peerCount, indexes)
-		for _, peer := range self.peers {
-			if i == indexes[0] {
-				poolLogger.Debugf("request %v missing blocks [%x/%x] from peer %s", len(hashes), hashes[0][:4], hashes[len(hashes)-1][:4], peer.id)
-				peer.requestBlocks(hashes)
-				indexes = indexes[1:]
-				if len(indexes) == 0 {
-					break
-				}
-			}
-			i++
-		}
-		self.wg.Done()
-		self.procWg.Done()
-	}()
-}
-
-func (self *BlockPool) getPeer(peerId string) (*peerInfo, bool) {
-	self.peersLock.RLock()
-	defer self.peersLock.RUnlock()
-	if self.peer != nil && self.peer.id == peerId {
-		return self.peer, true
-	}
-	info, ok := self.peers[peerId]
-	if !ok {
-		return nil, false
-	}
-	return info, false
-}
-
-func (self *peerInfo) addSection(hash []byte, section *section) (found *section) {
-	self.lock.Lock()
-	defer self.lock.Unlock()
-	key := string(hash)
-	found = self.sections[key]
-	poolLogger.DebugDetailf("[%s] section process stored for %s", sectionName(section), self.id)
-	self.sections[key] = section
-	return
-}
-
-func (self *BlockPool) switchPeer(oldPeer, newPeer *peerInfo) {
-	if newPeer != nil {
-		newPeer.quitC = make(chan bool)
-		poolLogger.DebugDetailf("[%s] activate section processes", newPeer.id)
-		var addSections []*section
-		for hash, section := range newPeer.sections {
-			// split sections get reorganised here
-			if string(section.top.hash) != hash {
-				addSections = append(addSections, section)
-				if entry := self.get([]byte(hash)); entry != nil {
-					addSections = append(addSections, entry.section)
-				}
-			}
-		}
-		for _, section := range addSections {
-			newPeer.sections[string(section.top.hash)] = section
-		}
-		for hash, section := range newPeer.sections {
-			// this will block if section process is waiting for peer lock
-			select {
-			case <-section.offC:
-				poolLogger.DebugDetailf("[%s][%x] section process complete - remove", newPeer.id, hash[:4])
-				delete(newPeer.sections, hash)
-			case section.controlC <- newPeer:
-				poolLogger.DebugDetailf("[%s][%x] activates section [%s]", newPeer.id, hash[:4], sectionName(section))
-			}
-		}
-		newPeer.lock.Lock()
-		headSection := newPeer.headSection
-		currentBlockHash := newPeer.currentBlockHash
-		newPeer.lock.Unlock()
-		if headSection == nil {
-			poolLogger.DebugDetailf("[%s] head section for [%s] not created, requesting info", newPeer.id, name(currentBlockHash))
-			self.requestHeadSection(newPeer)
-		} else {
-			if entry := self.get(currentBlockHash); entry != nil {
-				headSection = entry.section
-			}
-			poolLogger.DebugDetailf("[%s] activate chain at head section [%s] for current head [%s]", newPeer.id, sectionName(headSection), name(currentBlockHash))
-			self.activateChain(headSection, newPeer)
-		}
-	}
-	if oldPeer != nil {
-		poolLogger.DebugDetailf("[%s] quit section processes", oldPeer.id)
-		close(oldPeer.quitC)
-	}
-}
-
-func (self *BlockPool) getParent(sec *section) *section {
-	self.chainLock.RLock()
-	defer self.chainLock.RUnlock()
-	return sec.parent
-}
-
-func (self *BlockPool) getChild(sec *section) *section {
-	self.chainLock.RLock()
-	defer self.chainLock.RUnlock()
-	return sec.child
-}
-
-func newSection() (sec *section) {
-	sec = &section{
-		controlC:    make(chan *peerInfo),
-		suicideC:    make(chan bool),
-		blockChainC: make(chan bool),
-		offC:        make(chan bool),
-		forkC:       make(chan chan bool),
-	}
-	return
-}
-
-// link should only be called under chainLock
-func (self *BlockPool) link(parent *section, child *section) {
-	if parent != nil {
-		exChild := parent.child
-		parent.child = child
-		if exChild != nil && exChild != child {
-			poolLogger.Debugf("[%s] chain fork [%s] -> [%s]", sectionName(parent), sectionName(exChild), sectionName(child))
-			exChild.parent = nil
-		}
-	}
-	if child != nil {
-		exParent := child.parent
-		if exParent != nil && exParent != parent {
-			poolLogger.Debugf("[%s] chain reverse fork [%s] -> [%s]", sectionName(child), sectionName(exParent), sectionName(parent))
-			exParent.child = nil
-		}
-		child.parent = parent
-	}
-}
-
-func (self *BlockPool) get(hash []byte) (node *poolEntry) {
-	self.lock.RLock()
-	defer self.lock.RUnlock()
-	return self.pool[string(hash)]
-}
-
-func (self *BlockPool) set(hash []byte, node *poolEntry) {
-	self.lock.Lock()
-	defer self.lock.Unlock()
-	self.pool[string(hash)] = node
-}
diff --git a/eth/block_pool_test.go b/eth/block_pool_test.go
deleted file mode 100644
index 331dbe504..000000000
--- a/eth/block_pool_test.go
+++ /dev/null
@@ -1,983 +0,0 @@
-package eth
-
-import (
-	"fmt"
-	"log"
-	"math/big"
-	"os"
-	"sync"
-	"testing"
-	"time"
-
-	"github.com/ethereum/go-ethereum/core/types"
-	"github.com/ethereum/go-ethereum/crypto"
-	"github.com/ethereum/go-ethereum/ethutil"
-	ethlogger "github.com/ethereum/go-ethereum/logger"
-	"github.com/ethereum/go-ethereum/pow"
-)
-
-const waitTimeout = 60 // seconds
-
-var logsys = ethlogger.NewStdLogSystem(os.Stdout, log.LstdFlags, ethlogger.LogLevel(ethlogger.DebugDetailLevel))
-
-var ini = false
-
-func logInit() {
-	if !ini {
-		ethlogger.AddLogSystem(logsys)
-		ini = true
-	}
-}
-
-// test helpers
-func arrayEq(a, b []int) bool {
-	if len(a) != len(b) {
-		return false
-	}
-	for i := range a {
-		if a[i] != b[i] {
-			return false
-		}
-	}
-	return true
-}
-
-type intToHash map[int][]byte
-
-type hashToInt map[string]int
-
-// hashPool is a test helper, that allows random hashes to be referred to by integers
-type testHashPool struct {
-	intToHash
-	hashToInt
-	lock sync.Mutex
-}
-
-func newHash(i int) []byte {
-	return crypto.Sha3([]byte(string(i)))
-}
-
-func (self *testHashPool) indexesToHashes(indexes []int) (hashes [][]byte) {
-	self.lock.Lock()
-	defer self.lock.Unlock()
-	for _, i := range indexes {
-		hash, found := self.intToHash[i]
-		if !found {
-			hash = newHash(i)
-			self.intToHash[i] = hash
-			self.hashToInt[string(hash)] = i
-		}
-		hashes = append(hashes, hash)
-	}
-	return
-}
-
-func (self *testHashPool) hashesToIndexes(hashes [][]byte) (indexes []int) {
-	self.lock.Lock()
-	defer self.lock.Unlock()
-	for _, hash := range hashes {
-		i, found := self.hashToInt[string(hash)]
-		if !found {
-			i = -1
-		}
-		indexes = append(indexes, i)
-	}
-	return
-}
-
-// test blockChain is an integer trie
-type blockChain map[int][]int
-
-// blockPoolTester provides the interface between tests and a blockPool
-//
-// refBlockChain is used to guide which blocks will be accepted as valid
-// blockChain gives the current state of the blockchain and
-// accumulates inserts so that we can check the resulting chain
-type blockPoolTester struct {
-	hashPool      *testHashPool
-	lock          sync.RWMutex
-	refBlockChain blockChain
-	blockChain    blockChain
-	blockPool     *BlockPool
-	t             *testing.T
-}
-
-func newTestBlockPool(t *testing.T) (hashPool *testHashPool, blockPool *BlockPool, b *blockPoolTester) {
-	hashPool = &testHashPool{intToHash: make(intToHash), hashToInt: make(hashToInt)}
-	b = &blockPoolTester{
-		t:             t,
-		hashPool:      hashPool,
-		blockChain:    make(blockChain),
-		refBlockChain: make(blockChain),
-	}
-	b.blockPool = NewBlockPool(b.hasBlock, b.insertChain, b.verifyPoW)
-	blockPool = b.blockPool
-	return
-}
-
-func (self *blockPoolTester) Errorf(format string, params ...interface{}) {
-	fmt.Printf(format+"\n", params...)
-	self.t.Errorf(format, params...)
-}
-
-// blockPoolTester implements the 3 callbacks needed by the blockPool:
-// hasBlock, insetChain, verifyPoW
-func (self *blockPoolTester) hasBlock(block []byte) (ok bool) {
-	self.lock.RLock()
-	defer self.lock.RUnlock()
-	indexes := self.hashPool.hashesToIndexes([][]byte{block})
-	i := indexes[0]
-	_, ok = self.blockChain[i]
-	fmt.Printf("has block %v (%x...): %v\n", i, block[0:4], ok)
-	return
-}
-
-func (self *blockPoolTester) insertChain(blocks types.Blocks) error {
-	self.lock.RLock()
-	defer self.lock.RUnlock()
-	var parent, child int
-	var children, refChildren []int
-	var ok bool
-	for _, block := range blocks {
-		child = self.hashPool.hashesToIndexes([][]byte{block.Hash()})[0]
-		_, ok = self.blockChain[child]
-		if ok {
-			fmt.Printf("block %v already in blockchain\n", child)
-			continue // already in chain
-		}
-		parent = self.hashPool.hashesToIndexes([][]byte{block.ParentHeaderHash})[0]
-		children, ok = self.blockChain[parent]
-		if !ok {
-			return fmt.Errorf("parent %v not in blockchain ", parent)
-		}
-		ok = false
-		var found bool
-		refChildren, found = self.refBlockChain[parent]
-		if found {
-			for _, c := range refChildren {
-				if c == child {
-					ok = true
-				}
-			}
-			if !ok {
-				return fmt.Errorf("invalid block %v", child)
-			}
-		} else {
-			ok = true
-		}
-		if ok {
-			// accept any blocks if parent not in refBlockChain
-			fmt.Errorf("blockchain insert %v -> %v\n", parent, child)
-			self.blockChain[parent] = append(children, child)
-			self.blockChain[child] = nil
-		}
-	}
-	return nil
-}
-
-func (self *blockPoolTester) verifyPoW(pblock pow.Block) bool {
-	return true
-}
-
-// test helper that compares the resulting blockChain to the desired blockChain
-func (self *blockPoolTester) checkBlockChain(blockChain map[int][]int) {
-	for k, v := range self.blockChain {
-		fmt.Printf("got: %v -> %v\n", k, v)
-	}
-	for k, v := range blockChain {
-		fmt.Printf("expected: %v -> %v\n", k, v)
-	}
-	if len(blockChain) != len(self.blockChain) {
-		self.Errorf("blockchain incorrect (zlength differ)")
-	}
-	for k, v := range blockChain {
-		vv, ok := self.blockChain[k]
-		if !ok || !arrayEq(v, vv) {
-			self.Errorf("blockchain incorrect on %v -> %v (!= %v)", k, vv, v)
-		}
-	}
-}
-
-//
-
-// peerTester provides the peer callbacks for the blockPool
-// it registers actual callbacks so that result can be compared to desired behaviour
-// provides helper functions to mock the protocol calls to the blockPool
-type peerTester struct {
-	blockHashesRequests []int
-	blocksRequests      [][]int
-	blocksRequestsMap   map[int]bool
-	peerErrors          []int
-	blockPool           *BlockPool
-	hashPool            *testHashPool
-	lock                sync.RWMutex
-	id                  string
-	td                  int
-	currentBlock        int
-	t                   *testing.T
-}
-
-// peerTester constructor takes hashPool and blockPool from the blockPoolTester
-func (self *blockPoolTester) newPeer(id string, td int, cb int) *peerTester {
-	return &peerTester{
-		id:                id,
-		td:                td,
-		currentBlock:      cb,
-		hashPool:          self.hashPool,
-		blockPool:         self.blockPool,
-		t:                 self.t,
-		blocksRequestsMap: make(map[int]bool),
-	}
-}
-
-func (self *peerTester) Errorf(format string, params ...interface{}) {
-	fmt.Printf(format+"\n", params...)
-	self.t.Errorf(format, params...)
-}
-
-// helper to compare actual and expected block requests
-func (self *peerTester) checkBlocksRequests(blocksRequests ...[]int) {
-	if len(blocksRequests) > len(self.blocksRequests) {
-		self.Errorf("blocks requests incorrect (length differ)\ngot %v\nexpected %v", self.blocksRequests, blocksRequests)
-	} else {
-		for i, rr := range blocksRequests {
-			r := self.blocksRequests[i]
-			if !arrayEq(r, rr) {
-				self.Errorf("blocks requests incorrect\ngot %v\nexpected %v", self.blocksRequests, blocksRequests)
-			}
-		}
-	}
-}
-
-// helper to compare actual and expected block hash requests
-func (self *peerTester) checkBlockHashesRequests(blocksHashesRequests ...int) {
-	rr := blocksHashesRequests
-	self.lock.RLock()
-	r := self.blockHashesRequests
-	self.lock.RUnlock()
-	if len(r) != len(rr) {
-		self.Errorf("block hashes requests incorrect (length differ)\ngot %v\nexpected %v", r, rr)
-	} else {
-		if !arrayEq(r, rr) {
-			self.Errorf("block hashes requests incorrect\ngot %v\nexpected %v", r, rr)
-		}
-	}
-}
-
-// waiter function used by peer.AddBlocks
-// blocking until requests appear
-// since block requests are sent to any random peers
-// block request map is shared between peers
-// times out after a period
-func (self *peerTester) waitBlocksRequests(blocksRequest ...int) {
-	timeout := time.After(waitTimeout * time.Second)
-	rr := blocksRequest
-	for {
-		self.lock.RLock()
-		r := self.blocksRequestsMap
-		fmt.Printf("[%s] blocks request check %v (%v)\n", self.id, rr, r)
-		i := 0
-		for i = 0; i < len(rr); i++ {
-			_, ok := r[rr[i]]
-			if !ok {
-				break
-			}
-		}
-		self.lock.RUnlock()
-
-		if i == len(rr) {
-			return
-		}
-		time.Sleep(100 * time.Millisecond)
-		select {
-		case <-timeout:
-		default:
-		}
-	}
-}
-
-// waiter function used by peer.AddBlockHashes
-// blocking until requests appear
-// times out after a period
-func (self *peerTester) waitBlockHashesRequests(blocksHashesRequest int) {
-	timeout := time.After(waitTimeout * time.Second)
-	rr := blocksHashesRequest
-	for i := 0; ; {
-		self.lock.RLock()
-		r := self.blockHashesRequests
-		self.lock.RUnlock()
-		fmt.Printf("[%s] block hash request check %v (%v)\n", self.id, rr, r)
-		for ; i < len(r); i++ {
-			if rr == r[i] {
-				return
-			}
-		}
-		time.Sleep(100 * time.Millisecond)
-		select {
-		case <-timeout:
-		default:
-		}
-	}
-}
-
-// mocks a simple blockchain 0 (genesis) ... n (head)
-func (self *blockPoolTester) initRefBlockChain(n int) {
-	for i := 0; i < n; i++ {
-		self.refBlockChain[i] = []int{i + 1}
-	}
-}
-
-// peerTester functions that mimic protocol calls to the blockpool
-//  registers the peer with the blockPool
-func (self *peerTester) AddPeer() bool {
-	hash := self.hashPool.indexesToHashes([]int{self.currentBlock})[0]
-	return self.blockPool.AddPeer(big.NewInt(int64(self.td)), hash, self.id, self.requestBlockHashes, self.requestBlocks, self.peerError)
-}
-
-// peer sends blockhashes if and when gets a request
-func (self *peerTester) AddBlockHashes(indexes ...int) {
-	fmt.Printf("ready to add block hashes %v\n", indexes)
-
-	self.waitBlockHashesRequests(indexes[0])
-	fmt.Printf("adding block hashes %v\n", indexes)
-	hashes := self.hashPool.indexesToHashes(indexes)
-	i := 1
-	next := func() (hash []byte, ok bool) {
-		if i < len(hashes) {
-			hash = hashes[i]
-			ok = true
-			i++
-		}
-		return
-	}
-	self.blockPool.AddBlockHashes(next, self.id)
-}
-
-// peer sends blocks if and when there is a request
-// (in the shared request store, not necessarily to a person)
-func (self *peerTester) AddBlocks(indexes ...int) {
-	hashes := self.hashPool.indexesToHashes(indexes)
-	fmt.Printf("ready to add blocks %v\n", indexes[1:])
-	self.waitBlocksRequests(indexes[1:]...)
-	fmt.Printf("adding blocks %v \n", indexes[1:])
-	for i := 1; i < len(hashes); i++ {
-		fmt.Printf("adding block %v %x\n", indexes[i], hashes[i][:4])
-		self.blockPool.AddBlock(&types.Block{HeaderHash: ethutil.Bytes(hashes[i]), ParentHeaderHash: ethutil.Bytes(hashes[i-1])}, self.id)
-	}
-}
-
-// peer callbacks
-// -1 is special: not found (a hash never seen)
-// records block hashes requests by the blockPool
-func (self *peerTester) requestBlockHashes(hash []byte) error {
-	indexes := self.hashPool.hashesToIndexes([][]byte{hash})
-	fmt.Printf("[%s] blocks hash request %v %x\n", self.id, indexes[0], hash[:4])
-	self.lock.Lock()
-	defer self.lock.Unlock()
-	self.blockHashesRequests = append(self.blockHashesRequests, indexes[0])
-	return nil
-}
-
-// records block requests by the blockPool
-func (self *peerTester) requestBlocks(hashes [][]byte) error {
-	indexes := self.hashPool.hashesToIndexes(hashes)
-	fmt.Printf("blocks request %v %x...\n", indexes, hashes[0][:4])
-	self.lock.Lock()
-	defer self.lock.Unlock()
-	self.blocksRequests = append(self.blocksRequests, indexes)
-	for _, i := range indexes {
-		self.blocksRequestsMap[i] = true
-	}
-	return nil
-}
-
-// records the error codes of all the peerErrors found the blockPool
-func (self *peerTester) peerError(code int, format string, params ...interface{}) {
-	self.peerErrors = append(self.peerErrors, code)
-}
-
-// the actual tests
-func TestAddPeer(t *testing.T) {
-	logInit()
-	_, blockPool, blockPoolTester := newTestBlockPool(t)
-	peer0 := blockPoolTester.newPeer("peer0", 1, 0)
-	peer1 := blockPoolTester.newPeer("peer1", 2, 1)
-	peer2 := blockPoolTester.newPeer("peer2", 3, 2)
-	var peer *peerInfo
-
-	blockPool.Start()
-
-	// pool
-	best := peer0.AddPeer()
-	if !best {
-		t.Errorf("peer0 (TD=1) not accepted as best")
-	}
-	if blockPool.peer.id != "peer0" {
-		t.Errorf("peer0 (TD=1) not set as best")
-	}
-	// peer0.checkBlockHashesRequests(0)
-
-	best = peer2.AddPeer()
-	if !best {
-		t.Errorf("peer2 (TD=3) not accepted as best")
-	}
-	if blockPool.peer.id != "peer2" {
-		t.Errorf("peer2 (TD=3) not set as best")
-	}
-	peer2.waitBlocksRequests(2)
-
-	best = peer1.AddPeer()
-	if best {
-		t.Errorf("peer1 (TD=2) accepted as best")
-	}
-	if blockPool.peer.id != "peer2" {
-		t.Errorf("peer2 (TD=3) not set any more as best")
-	}
-	if blockPool.peer.td.Cmp(big.NewInt(int64(3))) != 0 {
-		t.Errorf("peer1 TD not set")
-	}
-
-	peer2.td = 4
-	peer2.currentBlock = 3
-	best = peer2.AddPeer()
-	if !best {
-		t.Errorf("peer2 (TD=4) not accepted as best")
-	}
-	if blockPool.peer.id != "peer2" {
-		t.Errorf("peer2 (TD=4) not set as best")
-	}
-	if blockPool.peer.td.Cmp(big.NewInt(int64(4))) != 0 {
-		t.Errorf("peer2 TD not updated")
-	}
-	peer2.waitBlocksRequests(3)
-
-	peer1.td = 3
-	peer1.currentBlock = 2
-	best = peer1.AddPeer()
-	if best {
-		t.Errorf("peer1 (TD=3) should not be set as best")
-	}
-	if blockPool.peer.id == "peer1" {
-		t.Errorf("peer1 (TD=3) should not be set as best")
-	}
-	peer, best = blockPool.getPeer("peer1")
-	if peer.td.Cmp(big.NewInt(int64(3))) != 0 {
-		t.Errorf("peer1 TD should be updated")
-	}
-
-	blockPool.RemovePeer("peer2")
-	peer, best = blockPool.getPeer("peer2")
-	if peer != nil {
-		t.Errorf("peer2 not removed")
-	}
-
-	if blockPool.peer.id != "peer1" {
-		t.Errorf("existing peer1 (TD=3) should be set as best peer")
-	}
-	peer1.waitBlocksRequests(2)
-
-	blockPool.RemovePeer("peer1")
-	peer, best = blockPool.getPeer("peer1")
-	if peer != nil {
-		t.Errorf("peer1 not removed")
-	}
-
-	if blockPool.peer.id != "peer0" {
-		t.Errorf("existing peer0 (TD=1) should be set as best peer")
-	}
-	peer0.waitBlocksRequests(0)
-
-	blockPool.RemovePeer("peer0")
-	peer, best = blockPool.getPeer("peer0")
-	if peer != nil {
-		t.Errorf("peer1 not removed")
-	}
-
-	// adding back earlier peer ok
-	peer0.currentBlock = 3
-	best = peer0.AddPeer()
-	if !best {
-		t.Errorf("peer0 (TD=1) should be set as best")
-	}
-
-	if blockPool.peer.id != "peer0" {
-		t.Errorf("peer0 (TD=1) should be set as best")
-	}
-	peer0.waitBlocksRequests(3)
-
-	blockPool.Stop()
-
-}
-
-func TestPeerWithKnownBlock(t *testing.T) {
-	logInit()
-	_, blockPool, blockPoolTester := newTestBlockPool(t)
-	blockPoolTester.refBlockChain[0] = nil
-	blockPoolTester.blockChain[0] = nil
-	blockPool.Start()
-
-	peer0 := blockPoolTester.newPeer("0", 1, 0)
-	peer0.AddPeer()
-
-	blockPool.Wait(waitTimeout * time.Second)
-	blockPool.Stop()
-	// no request on known block
-	peer0.checkBlockHashesRequests()
-}
-
-func TestPeerWithKnownParentBlock(t *testing.T) {
-	logInit()
-	_, blockPool, blockPoolTester := newTestBlockPool(t)
-	blockPoolTester.initRefBlockChain(1)
-	blockPoolTester.blockChain[0] = nil
-	blockPool.Start()
-
-	peer0 := blockPoolTester.newPeer("0", 1, 1)
-	peer0.AddPeer()
-	peer0.AddBlocks(0, 1)
-
-	blockPool.Wait(waitTimeout * time.Second)
-	blockPool.Stop()
-	peer0.checkBlocksRequests([]int{1})
-	peer0.checkBlockHashesRequests()
-	blockPoolTester.refBlockChain[1] = []int{}
-	blockPoolTester.checkBlockChain(blockPoolTester.refBlockChain)
-}
-
-func TestSimpleChain(t *testing.T) {
-	logInit()
-	_, blockPool, blockPoolTester := newTestBlockPool(t)
-	blockPoolTester.blockChain[0] = nil
-	blockPoolTester.initRefBlockChain(2)
-
-	blockPool.Start()
-
-	peer1 := blockPoolTester.newPeer("peer1", 1, 2)
-	peer1.AddPeer()
-	peer1.AddBlocks(1, 2)
-	go peer1.AddBlockHashes(2, 1, 0)
-	peer1.AddBlocks(0, 1)
-
-	blockPool.Wait(waitTimeout * time.Second)
-	blockPool.Stop()
-	blockPoolTester.refBlockChain[2] = []int{}
-	blockPoolTester.checkBlockChain(blockPoolTester.refBlockChain)
-}
-
-func TestChainConnectingWithParentHash(t *testing.T) {
-	logInit()
-	_, blockPool, blockPoolTester := newTestBlockPool(t)
-	blockPoolTester.blockChain[0] = nil
-	blockPoolTester.initRefBlockChain(3)
-
-	blockPool.Start()
-
-	peer1 := blockPoolTester.newPeer("peer1", 1, 3)
-	peer1.AddPeer()
-	go peer1.AddBlocks(2, 3)
-	go peer1.AddBlockHashes(3, 2, 1)
-	peer1.AddBlocks(0, 1, 2)
-
-	blockPool.Wait(waitTimeout * time.Second)
-	blockPool.Stop()
-	blockPoolTester.refBlockChain[3] = []int{}
-	blockPoolTester.checkBlockChain(blockPoolTester.refBlockChain)
-}
-
-func TestInvalidBlock(t *testing.T) {
-	logInit()
-	_, blockPool, blockPoolTester := newTestBlockPool(t)
-	blockPoolTester.blockChain[0] = nil
-	blockPoolTester.initRefBlockChain(2)
-	blockPoolTester.refBlockChain[2] = []int{}
-
-	blockPool.Start()
-
-	peer1 := blockPoolTester.newPeer("peer1", 1, 3)
-	peer1.AddPeer()
-	go peer1.AddBlocks(2, 3)
-	go peer1.AddBlockHashes(3, 2, 1, 0)
-	peer1.AddBlocks(0, 1, 2)
-
-	blockPool.Wait(waitTimeout * time.Second)
-	blockPool.Stop()
-	blockPoolTester.refBlockChain[2] = []int{}
-	blockPoolTester.checkBlockChain(blockPoolTester.refBlockChain)
-	if len(peer1.peerErrors) == 1 {
-		if peer1.peerErrors[0] != ErrInvalidBlock {
-			t.Errorf("wrong error, got %v, expected %v", peer1.peerErrors[0], ErrInvalidBlock)
-		}
-	} else {
-		t.Errorf("expected invalid block error, got nothing %v", peer1.peerErrors)
-	}
-}
-
-func TestVerifyPoW(t *testing.T) {
-	t.Skip("***FIX*** This test is broken")
-	logInit()
-	_, blockPool, blockPoolTester := newTestBlockPool(t)
-	blockPoolTester.blockChain[0] = nil
-	blockPoolTester.initRefBlockChain(3)
-	first := false
-	blockPoolTester.blockPool.verifyPoW = func(b pow.Block) bool {
-		bb, _ := b.(*types.Block)
-		indexes := blockPoolTester.hashPool.hashesToIndexes([][]byte{bb.Hash()})
-		if indexes[0] == 2 && !first {
-			first = true
-			return false
-		} else {
-			return true
-		}
-
-	}
-
-	blockPool.Start()
-
-	peer1 := blockPoolTester.newPeer("peer1", 1, 3)
-	peer1.AddPeer()
-	go peer1.AddBlocks(2, 3)
-	go peer1.AddBlockHashes(3, 2, 1, 0)
-	peer1.AddBlocks(0, 1, 2)
-
-	// blockPool.Wait(waitTimeout * time.Second)
-	time.Sleep(1 * time.Second)
-	blockPool.Stop()
-	blockPoolTester.refBlockChain[1] = []int{}
-	delete(blockPoolTester.refBlockChain, 2)
-	blockPoolTester.checkBlockChain(blockPoolTester.refBlockChain)
-	if len(peer1.peerErrors) == 1 {
-		if peer1.peerErrors[0] != ErrInvalidPoW {
-			t.Errorf("wrong error, got %v, expected %v", peer1.peerErrors[0], ErrInvalidPoW)
-		}
-	} else {
-		t.Errorf("expected invalid pow error, got nothing")
-	}
-}
-
-func TestMultiSectionChain(t *testing.T) {
-	logInit()
-	_, blockPool, blockPoolTester := newTestBlockPool(t)
-	blockPoolTester.blockChain[0] = nil
-	blockPoolTester.initRefBlockChain(5)
-
-	blockPool.Start()
-
-	peer1 := blockPoolTester.newPeer("peer1", 1, 5)
-
-	peer1.AddPeer()
-	go peer1.AddBlocks(4, 5)
-	go peer1.AddBlockHashes(5, 4, 3)
-	go peer1.AddBlocks(2, 3, 4)
-	go peer1.AddBlockHashes(3, 2, 1, 0)
-	peer1.AddBlocks(0, 1, 2)
-
-	blockPool.Wait(waitTimeout * time.Second)
-	blockPool.Stop()
-	blockPoolTester.refBlockChain[5] = []int{}
-	blockPoolTester.checkBlockChain(blockPoolTester.refBlockChain)
-}
-
-func TestNewBlocksOnPartialChain(t *testing.T) {
-	logInit()
-	_, blockPool, blockPoolTester := newTestBlockPool(t)
-	blockPoolTester.blockChain[0] = nil
-	blockPoolTester.initRefBlockChain(7)
-	blockPool.Start()
-
-	peer1 := blockPoolTester.newPeer("peer1", 1, 5)
-
-	peer1.AddPeer()
-	go peer1.AddBlocks(4, 5) // partially complete section
-	go peer1.AddBlockHashes(5, 4, 3)
-	peer1.AddBlocks(3, 4) // partially complete section
-	// peer1 found new blocks
-	peer1.td = 2
-	peer1.currentBlock = 7
-	peer1.AddPeer()
-	go peer1.AddBlocks(6, 7)
-	go peer1.AddBlockHashes(7, 6, 5)
-	go peer1.AddBlocks(2, 3)
-	go peer1.AddBlocks(5, 6)
-	go peer1.AddBlockHashes(3, 2, 1, 0) // tests that hash request from known chain root is remembered
-	peer1.AddBlocks(0, 1, 2)
-
-	blockPool.Wait(waitTimeout * time.Second)
-	blockPool.Stop()
-	blockPoolTester.refBlockChain[7] = []int{}
-	blockPoolTester.checkBlockChain(blockPoolTester.refBlockChain)
-}
-
-func TestPeerSwitchUp(t *testing.T) {
-	logInit()
-	_, blockPool, blockPoolTester := newTestBlockPool(t)
-	blockPoolTester.blockChain[0] = nil
-	blockPoolTester.initRefBlockChain(7)
-
-	blockPool.Start()
-
-	peer1 := blockPoolTester.newPeer("peer1", 1, 6)
-	peer2 := blockPoolTester.newPeer("peer2", 2, 7)
-	peer2.blocksRequestsMap = peer1.blocksRequestsMap
-
-	peer1.AddPeer()
-	go peer1.AddBlocks(5, 6)
-	go peer1.AddBlockHashes(6, 5, 4, 3) //
-	peer1.AddBlocks(2, 3)               // section partially complete, block 3 will be preserved after peer demoted
-	peer2.AddPeer()                     // peer2 is promoted as best peer, peer1 is demoted
-	go peer2.AddBlocks(6, 7)
-	go peer2.AddBlockHashes(7, 6)       //
-	go peer2.AddBlocks(4, 5)            // tests that block request for earlier section is remembered
-	go peer1.AddBlocks(3, 4)            // tests that connecting section by demoted peer is remembered and blocks are accepted from demoted peer
-	go peer2.AddBlockHashes(3, 2, 1, 0) // tests that known chain section is activated, hash requests from 3 is remembered
-	peer2.AddBlocks(0, 1, 2)            // final blocks linking to blockchain sent
-
-	blockPool.Wait(waitTimeout * time.Second)
-	blockPool.Stop()
-	blockPoolTester.refBlockChain[7] = []int{}
-	blockPoolTester.checkBlockChain(blockPoolTester.refBlockChain)
-}
-
-func TestPeerSwitchDown(t *testing.T) {
-	logInit()
-	_, blockPool, blockPoolTester := newTestBlockPool(t)
-	blockPoolTester.blockChain[0] = nil
-	blockPoolTester.initRefBlockChain(6)
-	blockPool.Start()
-
-	peer1 := blockPoolTester.newPeer("peer1", 1, 4)
-	peer2 := blockPoolTester.newPeer("peer2", 2, 6)
-	peer2.blocksRequestsMap = peer1.blocksRequestsMap
-
-	peer2.AddPeer()
-	peer2.AddBlocks(5, 6)                  // partially complete, section will be preserved
-	go peer2.AddBlockHashes(6, 5, 4)       //
-	peer2.AddBlocks(4, 5)                  //
-	blockPool.RemovePeer("peer2")          // peer2 disconnects
-	peer1.AddPeer()                        // inferior peer1 is promoted as best peer
-	go peer1.AddBlockHashes(4, 3, 2, 1, 0) //
-	go peer1.AddBlocks(3, 4)               // tests that section set by demoted peer is remembered and blocks are accepted , this connects the chain sections together
-	peer1.AddBlocks(0, 1, 2, 3)
-
-	blockPool.Wait(waitTimeout * time.Second)
-	blockPool.Stop()
-	blockPoolTester.refBlockChain[6] = []int{}
-	blockPoolTester.checkBlockChain(blockPoolTester.refBlockChain)
-}
-
-func TestPeerCompleteSectionSwitchDown(t *testing.T) {
-	logInit()
-	_, blockPool, blockPoolTester := newTestBlockPool(t)
-	blockPoolTester.blockChain[0] = nil
-	blockPoolTester.initRefBlockChain(6)
-	blockPool.Start()
-
-	peer1 := blockPoolTester.newPeer("peer1", 1, 4)
-	peer2 := blockPoolTester.newPeer("peer2", 2, 6)
-	peer2.blocksRequestsMap = peer1.blocksRequestsMap
-
-	peer2.AddPeer()
-	peer2.AddBlocks(5, 6)               // partially complete, section will be preserved
-	go peer2.AddBlockHashes(6, 5, 4)    //
-	peer2.AddBlocks(3, 4, 5)            // complete section
-	blockPool.RemovePeer("peer2")       // peer2 disconnects
-	peer1.AddPeer()                     // inferior peer1 is promoted as best peer
-	peer1.AddBlockHashes(4, 3, 2, 1, 0) // tests that hash request are directly connecting if the head block exists
-	peer1.AddBlocks(0, 1, 2, 3)
-
-	blockPool.Wait(waitTimeout * time.Second)
-	blockPool.Stop()
-	blockPoolTester.refBlockChain[6] = []int{}
-	blockPoolTester.checkBlockChain(blockPoolTester.refBlockChain)
-}
-
-func TestPeerSwitchBack(t *testing.T) {
-	logInit()
-	_, blockPool, blockPoolTester := newTestBlockPool(t)
-	blockPoolTester.blockChain[0] = nil
-	blockPoolTester.initRefBlockChain(8)
-
-	blockPool.Start()
-
-	peer1 := blockPoolTester.newPeer("peer1", 2, 11)
-	peer2 := blockPoolTester.newPeer("peer2", 1, 8)
-	peer2.blocksRequestsMap = peer1.blocksRequestsMap
-
-	peer2.AddPeer()
-	go peer2.AddBlocks(7, 8)
-	go peer2.AddBlockHashes(8, 7, 6)
-	go peer2.AddBlockHashes(6, 5, 4)
-	peer2.AddBlocks(4, 5)                  // section partially complete
-	peer1.AddPeer()                        // peer1 is promoted as best peer
-	go peer1.AddBlocks(10, 11)             //
-	peer1.AddBlockHashes(11, 10)           // only gives useless results
-	blockPool.RemovePeer("peer1")          // peer1 disconnects
-	go peer2.AddBlockHashes(4, 3, 2, 1, 0) // tests that asking for hashes from 4 is remembered
-	go peer2.AddBlocks(3, 4, 5, 6, 7, 8)   // tests that section 4, 5, 6 and 7, 8 are remembered for missing blocks
-	peer2.AddBlocks(0, 1, 2, 3)
-
-	blockPool.Wait(waitTimeout * time.Second)
-	blockPool.Stop()
-	blockPoolTester.refBlockChain[8] = []int{}
-	blockPoolTester.checkBlockChain(blockPoolTester.refBlockChain)
-}
-
-func TestForkSimple(t *testing.T) {
-	logInit()
-	_, blockPool, blockPoolTester := newTestBlockPool(t)
-	blockPoolTester.blockChain[0] = nil
-	blockPoolTester.initRefBlockChain(9)
-	blockPoolTester.refBlockChain[3] = []int{4, 7}
-	delete(blockPoolTester.refBlockChain, 6)
-
-	blockPool.Start()
-
-	peer1 := blockPoolTester.newPeer("peer1", 1, 9)
-	peer2 := blockPoolTester.newPeer("peer2", 2, 6)
-	peer2.blocksRequestsMap = peer1.blocksRequestsMap
-
-	peer1.AddPeer()
-	go peer1.AddBlocks(8, 9)
-	go peer1.AddBlockHashes(9, 8, 7, 3, 2)
-	peer1.AddBlocks(1, 2, 3, 7, 8)
-	peer2.AddPeer()                        // peer2 is promoted as best peer
-	go peer2.AddBlocks(5, 6)               //
-	go peer2.AddBlockHashes(6, 5, 4, 3, 2) // fork on 3 -> 4 (earlier child: 7)
-	go peer2.AddBlocks(1, 2, 3, 4, 5)
-	go peer2.AddBlockHashes(2, 1, 0)
-	peer2.AddBlocks(0, 1, 2)
-
-	blockPool.Wait(waitTimeout * time.Second)
-	blockPool.Stop()
-	blockPoolTester.refBlockChain[6] = []int{}
-	blockPoolTester.refBlockChain[3] = []int{4}
-	delete(blockPoolTester.refBlockChain, 7)
-	delete(blockPoolTester.refBlockChain, 8)
-	delete(blockPoolTester.refBlockChain, 9)
-	blockPoolTester.checkBlockChain(blockPoolTester.refBlockChain)
-
-}
-
-func TestForkSwitchBackByNewBlocks(t *testing.T) {
-	logInit()
-	_, blockPool, blockPoolTester := newTestBlockPool(t)
-	blockPoolTester.blockChain[0] = nil
-	blockPoolTester.initRefBlockChain(11)
-	blockPoolTester.refBlockChain[3] = []int{4, 7}
-	delete(blockPoolTester.refBlockChain, 6)
-
-	blockPool.Start()
-
-	peer1 := blockPoolTester.newPeer("peer1", 1, 9)
-	peer2 := blockPoolTester.newPeer("peer2", 2, 6)
-	peer2.blocksRequestsMap = peer1.blocksRequestsMap
-
-	peer1.AddPeer()
-	peer1.AddBlocks(8, 9)                  //
-	go peer1.AddBlockHashes(9, 8, 7, 3, 2) //
-	peer1.AddBlocks(7, 8)                  // partial section
-	peer2.AddPeer()                        //
-	peer2.AddBlocks(5, 6)                  //
-	go peer2.AddBlockHashes(6, 5, 4, 3, 2) // peer2 forks on block 3
-	peer2.AddBlocks(1, 2, 3, 4, 5)         //
-
-	// peer1 finds new blocks
-	peer1.td = 3
-	peer1.currentBlock = 11
-	peer1.AddPeer()
-	go peer1.AddBlocks(10, 11)
-	go peer1.AddBlockHashes(11, 10, 9)
-	peer1.AddBlocks(9, 10)
-	go peer1.AddBlocks(3, 7)         // tests that block requests on earlier fork are remembered
-	go peer1.AddBlockHashes(2, 1, 0) // tests that hash request from root of connecting chain section (added by demoted peer) is remembered
-	peer1.AddBlocks(0, 1)
-
-	blockPool.Wait(waitTimeout * time.Second)
-	blockPool.Stop()
-	blockPoolTester.refBlockChain[11] = []int{}
-	blockPoolTester.refBlockChain[3] = []int{7}
-	delete(blockPoolTester.refBlockChain, 6)
-	delete(blockPoolTester.refBlockChain, 5)
-	delete(blockPoolTester.refBlockChain, 4)
-	blockPoolTester.checkBlockChain(blockPoolTester.refBlockChain)
-
-}
-
-func TestForkSwitchBackByPeerSwitchBack(t *testing.T) {
-	logInit()
-	_, blockPool, blockPoolTester := newTestBlockPool(t)
-	blockPoolTester.blockChain[0] = nil
-	blockPoolTester.initRefBlockChain(9)
-	blockPoolTester.refBlockChain[3] = []int{4, 7}
-	delete(blockPoolTester.refBlockChain, 6)
-
-	blockPool.Start()
-
-	peer1 := blockPoolTester.newPeer("peer1", 1, 9)
-	peer2 := blockPoolTester.newPeer("peer2", 2, 6)
-	peer2.blocksRequestsMap = peer1.blocksRequestsMap
-
-	peer1.AddPeer()
-	go peer1.AddBlocks(8, 9)
-	go peer1.AddBlockHashes(9, 8, 7, 3, 2)
-	peer1.AddBlocks(7, 8)
-	peer2.AddPeer()
-	go peer2.AddBlocks(5, 6)               //
-	go peer2.AddBlockHashes(6, 5, 4, 3, 2) // peer2 forks on block 3
-	peer2.AddBlocks(2, 3, 4, 5)            //
-	blockPool.RemovePeer("peer2")          // peer2 disconnects, peer1 is promoted again as best peer
-	go peer1.AddBlocks(3, 7)               // tests that block requests on earlier fork are remembered and orphan section relinks to existing parent block
-	go peer1.AddBlocks(1, 2)               //
-	go peer1.AddBlockHashes(2, 1, 0)       //
-	peer1.AddBlocks(0, 1)
-
-	blockPool.Wait(waitTimeout * time.Second)
-	blockPool.Stop()
-	blockPoolTester.refBlockChain[9] = []int{}
-	blockPoolTester.refBlockChain[3] = []int{7}
-	delete(blockPoolTester.refBlockChain, 6)
-	delete(blockPoolTester.refBlockChain, 5)
-	delete(blockPoolTester.refBlockChain, 4)
-	blockPoolTester.checkBlockChain(blockPoolTester.refBlockChain)
-
-}
-
-func TestForkCompleteSectionSwitchBackByPeerSwitchBack(t *testing.T) {
-	logInit()
-	_, blockPool, blockPoolTester := newTestBlockPool(t)
-	blockPoolTester.blockChain[0] = nil
-	blockPoolTester.initRefBlockChain(9)
-	blockPoolTester.refBlockChain[3] = []int{4, 7}
-	delete(blockPoolTester.refBlockChain, 6)
-
-	blockPool.Start()
-
-	peer1 := blockPoolTester.newPeer("peer1", 1, 9)
-	peer2 := blockPoolTester.newPeer("peer2", 2, 6)
-	peer2.blocksRequestsMap = peer1.blocksRequestsMap
-
-	peer1.AddPeer()
-	go peer1.AddBlocks(8, 9)
-	go peer1.AddBlockHashes(9, 8, 7)
-	peer1.AddBlocks(3, 7, 8) // make sure this section is complete
-	time.Sleep(1 * time.Second)
-	go peer1.AddBlockHashes(7, 3, 2)       // block 3/7 is section boundary
-	peer1.AddBlocks(2, 3)                  // partially complete sections block 2 missing
-	peer2.AddPeer()                        //
-	go peer2.AddBlocks(5, 6)               //
-	go peer2.AddBlockHashes(6, 5, 4, 3, 2) // peer2 forks on block 3
-	peer2.AddBlocks(2, 3, 4, 5)            // block 2 still missing.
-	blockPool.RemovePeer("peer2")          // peer2 disconnects, peer1 is promoted again as best peer
-	// peer1.AddBlockHashes(7, 3)             // tests that hash request from fork root is remembered even though section process completed
-	go peer1.AddBlockHashes(2, 1, 0) //
-	peer1.AddBlocks(0, 1, 2)
-
-	blockPool.Wait(waitTimeout * time.Second)
-	blockPool.Stop()
-	blockPoolTester.refBlockChain[9] = []int{}
-	blockPoolTester.refBlockChain[3] = []int{7}
-	delete(blockPoolTester.refBlockChain, 6)
-	delete(blockPoolTester.refBlockChain, 5)
-	delete(blockPoolTester.refBlockChain, 4)
-	blockPoolTester.checkBlockChain(blockPoolTester.refBlockChain)
-
-}
diff --git a/eth/error.go b/eth/error.go
deleted file mode 100644
index 9c4a68481..000000000
--- a/eth/error.go
+++ /dev/null
@@ -1,72 +0,0 @@
-package eth
-
-import (
-	"fmt"
-)
-
-const (
-	ErrMsgTooLarge = iota
-	ErrDecode
-	ErrInvalidMsgCode
-	ErrProtocolVersionMismatch
-	ErrNetworkIdMismatch
-	ErrGenesisBlockMismatch
-	ErrNoStatusMsg
-	ErrExtraStatusMsg
-	ErrInvalidBlock
-	ErrInvalidPoW
-	ErrUnrequestedBlock
-	ErrInsufficientChainInfo
-)
-
-var errorToString = map[int]string{
-	ErrMsgTooLarge:             "Message too long",
-	ErrDecode:                  "Invalid message",
-	ErrInvalidMsgCode:          "Invalid message code",
-	ErrProtocolVersionMismatch: "Protocol version mismatch",
-	ErrNetworkIdMismatch:       "NetworkId mismatch",
-	ErrGenesisBlockMismatch:    "Genesis block mismatch",
-	ErrNoStatusMsg:             "No status message",
-	ErrExtraStatusMsg:          "Extra status message",
-	ErrInvalidBlock:            "Invalid block",
-	ErrInvalidPoW:              "Invalid PoW",
-	ErrUnrequestedBlock:        "Unrequested block",
-	ErrInsufficientChainInfo:   "Insufficient chain info",
-}
-
-type protocolError struct {
-	Code    int
-	fatal   bool
-	message string
-	format  string
-	params  []interface{}
-	// size    int
-}
-
-func newProtocolError(code int, format string, params ...interface{}) *protocolError {
-	return &protocolError{Code: code, format: format, params: params}
-}
-
-func ProtocolError(code int, format string, params ...interface{}) (err *protocolError) {
-	err = newProtocolError(code, format, params...)
-	// report(err)
-	return
-}
-
-func (self protocolError) Error() (message string) {
-	if len(message) == 0 {
-		var ok bool
-		self.message, ok = errorToString[self.Code]
-		if !ok {
-			panic("invalid error code")
-		}
-		if self.format != "" {
-			self.message += ": " + fmt.Sprintf(self.format, self.params...)
-		}
-	}
-	return self.message
-}
-
-func (self *protocolError) Fatal() bool {
-	return self.fatal
-}
diff --git a/eth/protocol.go b/eth/protocol.go
index 8221c1b29..ee2316836 100644
--- a/eth/protocol.go
+++ b/eth/protocol.go
@@ -7,6 +7,7 @@ import (
 	"math/big"
 
 	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/errs"
 	"github.com/ethereum/go-ethereum/ethutil"
 	"github.com/ethereum/go-ethereum/p2p"
 	"github.com/ethereum/go-ethereum/rlp"
@@ -17,6 +18,8 @@ const (
 	NetworkId          = 0
 	ProtocolLength     = uint64(8)
 	ProtocolMaxMsgSize = 10 * 1024 * 1024
+	maxHashes          = 256
+	maxBlocks          = 64
 )
 
 // eth protocol message codes
@@ -31,6 +34,28 @@ const (
 	NewBlockMsg
 )
 
+const (
+	ErrMsgTooLarge = iota
+	ErrDecode
+	ErrInvalidMsgCode
+	ErrProtocolVersionMismatch
+	ErrNetworkIdMismatch
+	ErrGenesisBlockMismatch
+	ErrNoStatusMsg
+	ErrExtraStatusMsg
+)
+
+var errorToString = map[int]string{
+	ErrMsgTooLarge:             "Message too long",
+	ErrDecode:                  "Invalid message",
+	ErrInvalidMsgCode:          "Invalid message code",
+	ErrProtocolVersionMismatch: "Protocol version mismatch",
+	ErrNetworkIdMismatch:       "NetworkId mismatch",
+	ErrGenesisBlockMismatch:    "Genesis block mismatch",
+	ErrNoStatusMsg:             "No status message",
+	ErrExtraStatusMsg:          "Extra status message",
+}
+
 // ethProtocol represents the ethereum wire protocol
 // instance is running on each peer
 type ethProtocol struct {
@@ -40,6 +65,7 @@ type ethProtocol struct {
 	peer         *p2p.Peer
 	id           string
 	rw           p2p.MsgReadWriter
+	errors       *errs.Errors
 }
 
 // backend is the interface the ethereum protocol backend should implement
@@ -58,7 +84,7 @@ type chainManager interface {
 type blockPool interface {
 	AddBlockHashes(next func() ([]byte, bool), peerId string)
 	AddBlock(block *types.Block, peerId string)
-	AddPeer(td *big.Int, currentBlock []byte, peerId string, requestHashes func([]byte) error, requestBlocks func([][]byte) error, peerError func(int, string, ...interface{})) (best bool)
+	AddPeer(td *big.Int, currentBlock []byte, peerId string, requestHashes func([]byte) error, requestBlocks func([][]byte) error, peerError func(*errs.Error)) (best bool)
 	RemovePeer(peerId string)
 }
 
@@ -68,8 +94,6 @@ type newBlockMsgData struct {
 	TD    *big.Int
 }
 
-const maxHashes = 255
-
 type getBlockHashesMsgData struct {
 	Hash   []byte
 	Amount uint64
@@ -99,7 +123,11 @@ func runEthProtocol(txPool txPool, chainManager chainManager, blockPool blockPoo
 		blockPool:    blockPool,
 		rw:           rw,
 		peer:         peer,
-		id:           fmt.Sprintf("%x", id[:8]),
+		errors: &errs.Errors{
+			Package: "ETH",
+			Errors:  errorToString,
+		},
+		id: fmt.Sprintf("%x", id[:8]),
 	}
 	err = self.handleStatus()
 	if err == nil {
@@ -145,7 +173,6 @@ func (self *ethProtocol) handle() error {
 			return self.protoError(ErrDecode, "->msg %v: %v", msg, err)
 		}
 
-		//request.Amount = uint64(math.Min(float64(maxHashes), float64(request.Amount)))
 		if request.Amount > maxHashes {
 			request.Amount = maxHashes
 		}
@@ -153,7 +180,6 @@ func (self *ethProtocol) handle() error {
 		return p2p.EncodeMsg(self.rw, BlockHashesMsg, ethutil.ByteSliceToInterface(hashes)...)
 
 	case BlockHashesMsg:
-		// TODO: redo using lazy decode , this way very inefficient on known chains
 		msgStream := rlp.NewStream(msg.Payload)
 		var err error
 		var i int
@@ -191,7 +217,7 @@ func (self *ethProtocol) handle() error {
 			if block != nil {
 				blocks = append(blocks, block)
 			}
-			if i == blockHashesBatchSize {
+			if i == maxBlocks {
 				break
 			}
 		}
@@ -218,7 +244,7 @@ func (self *ethProtocol) handle() error {
 		}
 		hash := request.Block.Hash()
 		// to simplify backend interface adding a new block
-		// uses AddPeer followed by AddHashes, AddBlock only if peer is the best peer
+		// uses AddPeer followed by AddBlock only if peer is the best peer
 		// (or selected as new best peer)
 		if self.blockPool.AddPeer(request.TD, hash, self.id, self.requestBlockHashes, self.requestBlocks, self.protoErrorDisconnect) {
 			self.blockPool.AddBlock(request.Block, self.id)
@@ -277,7 +303,7 @@ func (self *ethProtocol) handleStatus() error {
 
 	_, _, genesisBlock := self.chainManager.Status()
 
-	if bytes.Compare(status.GenesisBlock, genesisBlock) != 0 {
+	if !bytes.Equal(status.GenesisBlock, genesisBlock) {
 		return self.protoError(ErrGenesisBlockMismatch, "%x (!= %x)", status.GenesisBlock, genesisBlock)
 	}
 
@@ -297,8 +323,8 @@ func (self *ethProtocol) handleStatus() error {
 }
 
 func (self *ethProtocol) requestBlockHashes(from []byte) error {
-	self.peer.Debugf("fetching hashes (%d) %x...\n", blockHashesBatchSize, from[0:4])
-	return p2p.EncodeMsg(self.rw, GetBlockHashesMsg, interface{}(from), uint64(blockHashesBatchSize))
+	self.peer.Debugf("fetching hashes (%d) %x...\n", maxHashes, from[0:4])
+	return p2p.EncodeMsg(self.rw, GetBlockHashesMsg, interface{}(from), uint64(maxHashes))
 }
 
 func (self *ethProtocol) requestBlocks(hashes [][]byte) error {
@@ -306,26 +332,17 @@ func (self *ethProtocol) requestBlocks(hashes [][]byte) error {
 	return p2p.EncodeMsg(self.rw, GetBlocksMsg, ethutil.ByteSliceToInterface(hashes)...)
 }
 
-func (self *ethProtocol) protoError(code int, format string, params ...interface{}) (err *protocolError) {
-	err = ProtocolError(code, format, params...)
-	if err.Fatal() {
-		self.peer.Errorln("err %v", err)
-		// disconnect
-	} else {
-		self.peer.Debugf("fyi %v", err)
-	}
+func (self *ethProtocol) protoError(code int, format string, params ...interface{}) (err *errs.Error) {
+	err = self.errors.New(code, format, params...)
+	err.Log(self.peer.Logger)
 	return
 }
 
-func (self *ethProtocol) protoErrorDisconnect(code int, format string, params ...interface{}) {
-	err := ProtocolError(code, format, params...)
+func (self *ethProtocol) protoErrorDisconnect(err *errs.Error) {
+	err.Log(self.peer.Logger)
 	if err.Fatal() {
-		self.peer.Errorln("err %v", err)
-		// disconnect
-	} else {
-		self.peer.Debugf("fyi %v", err)
+		self.peer.Disconnect(p2p.DiscSubprotocolError)
 	}
-
 }
 
 func (self *ethProtocol) propagateTxs() {
diff --git a/eth/protocol_test.go b/eth/protocol_test.go
index a91806a1c..f499d033e 100644
--- a/eth/protocol_test.go
+++ b/eth/protocol_test.go
@@ -11,13 +11,23 @@ import (
 
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/errs"
 	"github.com/ethereum/go-ethereum/ethutil"
 	ethlogger "github.com/ethereum/go-ethereum/logger"
 	"github.com/ethereum/go-ethereum/p2p"
 	"github.com/ethereum/go-ethereum/p2p/discover"
 )
 
-var sys = ethlogger.NewStdLogSystem(os.Stdout, log.LstdFlags, ethlogger.LogLevel(ethlogger.DebugDetailLevel))
+var logsys = ethlogger.NewStdLogSystem(os.Stdout, log.LstdFlags, ethlogger.LogLevel(ethlogger.DebugDetailLevel))
+
+var ini = false
+
+func logInit() {
+	if !ini {
+		ethlogger.AddLogSystem(logsys)
+		ini = true
+	}
+}
 
 type testMsgReadWriter struct {
 	in  chan p2p.Msg
@@ -64,7 +74,7 @@ type testChainManager struct {
 type testBlockPool struct {
 	addBlockHashes func(next func() ([]byte, bool), peerId string)
 	addBlock       func(block *types.Block, peerId string) (err error)
-	addPeer        func(td *big.Int, currentBlock []byte, peerId string, requestHashes func([]byte) error, requestBlocks func([][]byte) error, peerError func(int, string, ...interface{})) (best bool)
+	addPeer        func(td *big.Int, currentBlock []byte, peerId string, requestHashes func([]byte) error, requestBlocks func([][]byte) error, peerError func(*errs.Error)) (best bool)
 	removePeer     func(peerId string)
 }
 
@@ -116,7 +126,7 @@ func (self *testBlockPool) AddBlock(block *types.Block, peerId string) {
 	}
 }
 
-func (self *testBlockPool) AddPeer(td *big.Int, currentBlock []byte, peerId string, requestBlockHashes func([]byte) error, requestBlocks func([][]byte) error, peerError func(int, string, ...interface{})) (best bool) {
+func (self *testBlockPool) AddPeer(td *big.Int, currentBlock []byte, peerId string, requestBlockHashes func([]byte) error, requestBlocks func([][]byte) error, peerError func(*errs.Error)) (best bool) {
 	if self.addPeer != nil {
 		best = self.addPeer(td, currentBlock, peerId, requestBlockHashes, requestBlocks, peerError)
 	}
@@ -169,7 +179,7 @@ func (self *ethProtocolTester) checkError(expCode int, delay time.Duration) (err
 		self.t.Errorf("no error after %v, expected %v", delay, expCode)
 		return
 	}
-	perr, ok := err.(*protocolError)
+	perr, ok := err.(*errs.Error)
 	if ok && perr != nil {
 		if code := perr.Code; code != expCode {
 			self.t.Errorf("expected protocol error (code %v), got %v (%v)", expCode, code, err)
diff --git a/eth/test/README.md b/eth/test/README.md
deleted file mode 100644
index 65728efa5..000000000
--- a/eth/test/README.md
+++ /dev/null
@@ -1,27 +0,0 @@
-= Integration tests for eth protocol and blockpool 
-
-This is a simple suite of tests to fire up a local test node with peers to test blockchain synchronisation and download. 
-The scripts call ethereum (assumed to be compiled in go-ethereum root). 
-
-To run a test:
-
-    . run.sh 00 02
-
-Without arguments, all tests are run. 
-
-Peers are launched with preloaded imported chains. In order to prevent them from synchronizing with each other they are set with `-dial=false` and `-maxpeer 1` options. They log into `/tmp/eth.test/nodes/XX` where XX is the last two digits of their port. 
-
-Chains to import can be bootstrapped by letting nodes mine for some time. This is done with 
-
-    . bootstrap.sh 
-
-Only the relative timing and forks matter so they should work if the bootstrap script is rerun. 
-The reference blockchain of tests are soft links to these import chains and check at the end of a test run. 
-
-Connecting to peers and exporting blockchain is scripted with JS files executed by the JSRE, see `tests/XX.sh`. 
-
-Each test is set with a timeout. This may vary on different computers so adjust sensibly. 
-If you kill a test before it completes, do not forget to kill all the background processes, since they will impact the result. Use:
-
-    killall ethereum
-
diff --git a/eth/test/bootstrap.sh b/eth/test/bootstrap.sh
deleted file mode 100644
index 3da038be8..000000000
--- a/eth/test/bootstrap.sh
+++ /dev/null
@@ -1,9 +0,0 @@
-#!/bin/bash
-# bootstrap chains - used to regenerate tests/chains/*.chain
-
-mkdir -p chains
-bash ./mine.sh 00 10
-bash ./mine.sh 01 5 00
-bash ./mine.sh 02 10 00
-bash ./mine.sh 03 5 02
-bash ./mine.sh 04 10 02
\ No newline at end of file
diff --git a/eth/test/chains/00.chain b/eth/test/chains/00.chain
deleted file mode 100755
index ad3c05b24..000000000
--- a/eth/test/chains/00.chain
+++ /dev/null
diff --git a/eth/test/chains/01.chain b/eth/test/chains/01.chain
deleted file mode 100755
index 56c9aef65..000000000
--- a/eth/test/chains/01.chain
+++ /dev/null
diff --git a/eth/test/chains/02.chain b/eth/test/chains/02.chain
deleted file mode 100755
index 440c92d65..000000000
--- a/eth/test/chains/02.chain
+++ /dev/null
diff --git a/eth/test/chains/03.chain b/eth/test/chains/03.chain
deleted file mode 100755
index 1cc7570ab..000000000
--- a/eth/test/chains/03.chain
+++ /dev/null
diff --git a/eth/test/chains/04.chain b/eth/test/chains/04.chain
deleted file mode 100755
index d4e5b1aa8..000000000
--- a/eth/test/chains/04.chain
+++ /dev/null
diff --git a/eth/test/mine.sh b/eth/test/mine.sh
deleted file mode 100644
index 0d95db1e4..000000000
--- a/eth/test/mine.sh
+++ /dev/null
@@ -1,20 +0,0 @@
-#!/bin/bash
-# bash ./mine.sh node_id timeout(sec) [basechain]
-ETH=../../ethereum
-MINE="$ETH -datadir tmp/nodes/$1 -seed=false -port '' -shh=false -id test$1"
-rm -rf tmp/nodes/$1
-echo "Creating chain $1..."
-if [[ "" !=  "$3" ]]; then
-  CHAIN="chains/$3.chain"
-  CHAINARG="-chain $CHAIN"
-  $MINE -mine $CHAINARG -loglevel 3 | grep 'importing'
-fi
-$MINE -mine -loglevel 0 &
-PID=$!
-sleep $2
-kill $PID
-$MINE -loglevel 3 <(echo "eth.export(\"chains/$1.chain\")") > /tmp/eth.test/mine.tmp &
-PID=$!
-sleep 1
-kill $PID
-cat /tmp/eth.test/mine.tmp | grep 'exporting'
diff --git a/eth/test/run.sh b/eth/test/run.sh
deleted file mode 100644
index 5229af035..000000000
--- a/eth/test/run.sh
+++ /dev/null
@@ -1,53 +0,0 @@
-#!/bin/bash
-# bash run.sh (testid0 testid1 ...)
-# runs tests tests/testid0.sh tests/testid1.sh ...
-# without arguments, it runs all tests
-
-. tests/common.sh
-
-TESTS=
-
-if [ "$#" -eq 0 ]; then
-  for NAME in tests/??.sh; do
-    i=`basename $NAME .sh`
-    TESTS="$TESTS $i"
-  done
-else
-  TESTS=$@
-fi
-
-ETH=../../ethereum
-DIR="/tmp/eth.test/nodes"
-TIMEOUT=10
-
-mkdir -p $DIR/js
-
-echo "running tests $TESTS"
-for NAME in $TESTS; do
-  PIDS=
-  CHAIN="tests/$NAME.chain"
-  JSFILE="$DIR/js/$NAME.js"
-  CHAIN_TEST="$DIR/$NAME/chain"
-
-  echo "RUN: test $NAME"
-  cat tests/common.js > $JSFILE
-  . tests/$NAME.sh
-  sleep $TIMEOUT
-  echo "timeout after $TIMEOUT seconds: killing $PIDS"
-  kill $PIDS
-  if [ -r "$CHAIN" ]; then
-    if diff $CHAIN $CHAIN_TEST >/dev/null ; then
-      echo "chain ok: $CHAIN=$CHAIN_TEST"
-    else
-      echo "FAIL: chains differ: expected $CHAIN ; got $CHAIN_TEST"
-      continue
-    fi
-  fi
-  ERRORS=$DIR/errors
-  if [ -r "$ERRORS" ]; then
-    echo "FAIL: "
-    cat $ERRORS
-  else
-    echo PASS
-  fi
-done
\ No newline at end of file
diff --git a/eth/test/tests/00.chain b/eth/test/tests/00.chain
deleted file mode 120000
index 9655cb3df..000000000
--- a/eth/test/tests/00.chain
+++ /dev/null
@@ -1 +0,0 @@
-../chains/01.chain
\ No newline at end of file
diff --git a/eth/test/tests/00.sh b/eth/test/tests/00.sh
deleted file mode 100644
index 9c5077164..000000000
--- a/eth/test/tests/00.sh
+++ /dev/null
@@ -1,13 +0,0 @@
-#!/bin/bash
-
-TIMEOUT=4
-
-cat >> $JSFILE <<EOF
-eth.addPeer("localhost:30311");
-sleep(1000)
-eth.export("$CHAIN_TEST");
-EOF
-
-peer 11 01
-test_node $NAME "" -loglevel 5 $JSFILE
-
diff --git a/eth/test/tests/01.chain b/eth/test/tests/01.chain
deleted file mode 120000
index ae65ccb37..000000000
--- a/eth/test/tests/01.chain
+++ /dev/null
@@ -1 +0,0 @@
-../chains/02.chain
\ No newline at end of file
diff --git a/eth/test/tests/01.sh b/eth/test/tests/01.sh
deleted file mode 100644
index 1601e0dfb..000000000
--- a/eth/test/tests/01.sh
+++ /dev/null
@@ -1,18 +0,0 @@
-#!/bin/bash
-
-TIMEOUT=5
-
-cat >> $JSFILE <<EOF
-eth.addPeer("localhost:30311");
-log("added peer localhost:30311");
-sleep(1000);
-log("added peer localhost:30312");
-eth.addPeer("localhost:30312");
-sleep(3000);
-eth.export("$CHAIN_TEST");
-EOF
-
-peer 11 01
-peer 12 02
-test_node $NAME "" -loglevel 5 $JSFILE
-
diff --git a/eth/test/tests/02.chain b/eth/test/tests/02.chain
deleted file mode 120000
index 9655cb3df..000000000
--- a/eth/test/tests/02.chain
+++ /dev/null
@@ -1 +0,0 @@
-../chains/01.chain
\ No newline at end of file
diff --git a/eth/test/tests/02.sh b/eth/test/tests/02.sh
deleted file mode 100644
index 619217ed8..000000000
--- a/eth/test/tests/02.sh
+++ /dev/null
@@ -1,19 +0,0 @@
-#!/bin/bash
-
-TIMEOUT=6
-
-cat >> $JSFILE <<EOF
-eth.addPeer("localhost:30311");
-sleep(200);
-eth.addPeer("localhost:30312");
-sleep(3000);
-eth.export("$CHAIN_TEST");
-EOF
-
-peer 11 01
-peer 12 02
-P12ID=$PID
-test_node $NAME "" -loglevel 5 $JSFILE
-sleep 0.3
-kill $P12ID
-
diff --git a/eth/test/tests/03.chain b/eth/test/tests/03.chain
deleted file mode 120000
index b07c49a30..000000000
--- a/eth/test/tests/03.chain
+++ /dev/null
@@ -1 +0,0 @@
-../chains/12k.chain
\ No newline at end of file
diff --git a/eth/test/tests/03.sh b/eth/test/tests/03.sh
deleted file mode 100644
index d7dba737f..000000000
--- a/eth/test/tests/03.sh
+++ /dev/null
@@ -1,14 +0,0 @@
-#!/bin/bash
-
-TIMEOUT=12
-
-cat >> $JSFILE <<EOF
-eth.addPeer("localhost:30311");
-sleep(10000);
-eth.export("$CHAIN_TEST");
-EOF
-
-peer 11 12k
-sleep 2
-test_node $NAME "" -loglevel 5 $JSFILE
-
diff --git a/eth/test/tests/04.sh b/eth/test/tests/04.sh
deleted file mode 100644
index d77c360ba..000000000
--- a/eth/test/tests/04.sh
+++ /dev/null
@@ -1,17 +0,0 @@
-#!/bin/bash
-
-TIMEOUT=15
-
-cat >> $JSFILE <<EOF
-eth.addPeer("localhost:30311");
-sleep(200);
-eth.addPeer("localhost:30312");
-sleep(13000);
-eth.export("$CHAIN_TEST");
-EOF
-
-peer 11 01 -mine
-peer 12 02
-test_node $NAME "" -loglevel 5 $JSFILE
-sleep 6
-cat $DIR/$NAME/debug.log | grep 'best peer'
diff --git a/eth/test/tests/05.sh b/eth/test/tests/05.sh
deleted file mode 100644
index 0a0f94df5..000000000
--- a/eth/test/tests/05.sh
+++ /dev/null
@@ -1,20 +0,0 @@
-#!/bin/bash
-
-TIMEOUT=60
-
-cat >> $JSFILE <<EOF
-eth.addPeer("localhost:30311");
-sleep(200);
-eth.addPeer("localhost:30312");
-eth.addPeer("localhost:30313");
-eth.addPeer("localhost:30314");
-sleep(3000);
-eth.export("$CHAIN_TEST");
-EOF
-
-peer 11 01 -mine
-peer 12 02 -mine
-peer 13 03
-peer 14 04
-test_node $NAME "" -loglevel 5 $JSFILE
-
diff --git a/eth/test/tests/common.js b/eth/test/tests/common.js
deleted file mode 100644
index 206ebf145..000000000
--- a/eth/test/tests/common.js
+++ /dev/null
@@ -1,9 +0,0 @@
-function log(text) {
-  console.log("[JS TEST SCRIPT] " + text);
-}
-
-function sleep(seconds) {
-    var now = new Date().getTime();
-    while(new Date().getTime() < now + seconds){}
-}
-
diff --git a/eth/test/tests/common.sh b/eth/test/tests/common.sh
deleted file mode 100644
index f66cfb43e..000000000
--- a/eth/test/tests/common.sh
+++ /dev/null
@@ -1,20 +0,0 @@
-#!/bin/bash
-
-# launched by run.sh
-function test_node {
-  rm -rf $DIR/$1
-  ARGS="-datadir $DIR/$1 -debug debug -seed=false -shh=false -id test$1 -port 303$1"
-  if [ "" != "$2" ]; then
-    chain="chains/$2.chain"
-    echo "import chain $chain"
-    $ETH $ARGS -loglevel 3 -chain $chain | grep CLI |grep import
-  fi
-  echo "starting test node $1 with args $ARGS ${@:3}"
-  $ETH $ARGS  ${@:3} &
-  PID=$!
-  PIDS="$PIDS $PID"
-}
-
-function peer {
-  test_node $@ -loglevel 5 -logfile debug.log -maxpeer 1 -dial=false
-}
\ No newline at end of file
diff --git a/logger/loggers.go b/logger/loggers.go
index 147b2b85f..25263853a 100644
--- a/logger/loggers.go
+++ b/logger/loggers.go
@@ -42,74 +42,74 @@ func NewLogger(tag string) *Logger {
 	return &Logger{"[" + tag + "] "}
 }
 
-func (logger *Logger) sendln(level LogLevel, v ...interface{}) {
+func (logger *Logger) Sendln(level LogLevel, v ...interface{}) {
 	logMessageC <- message{level, logger.tag + fmt.Sprintln(v...)}
 }
 
-func (logger *Logger) sendf(level LogLevel, format string, v ...interface{}) {
+func (logger *Logger) Sendf(level LogLevel, format string, v ...interface{}) {
 	logMessageC <- message{level, logger.tag + fmt.Sprintf(format, v...)}
 }
 
 // Errorln writes a message with ErrorLevel.
 func (logger *Logger) Errorln(v ...interface{}) {
-	logger.sendln(ErrorLevel, v...)
+	logger.Sendln(ErrorLevel, v...)
 }
 
 // Warnln writes a message with WarnLevel.
 func (logger *Logger) Warnln(v ...interface{}) {
-	logger.sendln(WarnLevel, v...)
+	logger.Sendln(WarnLevel, v...)
 }
 
 // Infoln writes a message with InfoLevel.
 func (logger *Logger) Infoln(v ...interface{}) {
-	logger.sendln(InfoLevel, v...)
+	logger.Sendln(InfoLevel, v...)
 }
 
 // Debugln writes a message with DebugLevel.
 func (logger *Logger) Debugln(v ...interface{}) {
-	logger.sendln(DebugLevel, v...)
+	logger.Sendln(DebugLevel, v...)
 }
 
 // DebugDetailln writes a message with DebugDetailLevel.
 func (logger *Logger) DebugDetailln(v ...interface{}) {
-	logger.sendln(DebugDetailLevel, v...)
+	logger.Sendln(DebugDetailLevel, v...)
 }
 
 // Errorf writes a message with ErrorLevel.
 func (logger *Logger) Errorf(format string, v ...interface{}) {
-	logger.sendf(ErrorLevel, format, v...)
+	logger.Sendf(ErrorLevel, format, v...)
 }
 
 // Warnf writes a message with WarnLevel.
 func (logger *Logger) Warnf(format string, v ...interface{}) {
-	logger.sendf(WarnLevel, format, v...)
+	logger.Sendf(WarnLevel, format, v...)
 }
 
 // Infof writes a message with InfoLevel.
 func (logger *Logger) Infof(format string, v ...interface{}) {
-	logger.sendf(InfoLevel, format, v...)
+	logger.Sendf(InfoLevel, format, v...)
 }
 
 // Debugf writes a message with DebugLevel.
 func (logger *Logger) Debugf(format string, v ...interface{}) {
-	logger.sendf(DebugLevel, format, v...)
+	logger.Sendf(DebugLevel, format, v...)
 }
 
 // DebugDetailf writes a message with DebugDetailLevel.
 func (logger *Logger) DebugDetailf(format string, v ...interface{}) {
-	logger.sendf(DebugDetailLevel, format, v...)
+	logger.Sendf(DebugDetailLevel, format, v...)
 }
 
 // Fatalln writes a message with ErrorLevel and exits the program.
 func (logger *Logger) Fatalln(v ...interface{}) {
-	logger.sendln(ErrorLevel, v...)
+	logger.Sendln(ErrorLevel, v...)
 	Flush()
 	os.Exit(0)
 }
 
 // Fatalf writes a message with ErrorLevel and exits the program.
 func (logger *Logger) Fatalf(format string, v ...interface{}) {
-	logger.sendf(ErrorLevel, format, v...)
+	logger.Sendf(ErrorLevel, format, v...)
 	Flush()
 	os.Exit(0)
 }