eth: kill off protocol eth/60 in preparation for eth/62

1 files changed, 3 insertions, 394 deletions

diff --git a/eth/downloader/downloader.go b/eth/downloader/downloader.go
index 6a6bce644..b28879ee6 100644
--- a/eth/downloader/downloader.go
+++ b/eth/downloader/downloader.go
@@ -18,11 +18,9 @@
 package downloader
 
 import (
-	"bytes"
 	"errors"
 	"math"
 	"math/big"
-	"math/rand"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -37,8 +35,8 @@ import (
 )
 
 const (
-	eth60 = 60 // Constant to check for old protocol support
-	eth61 = 61 // Constant to check for new protocol support
+	eth61 = 61 // Constant to check for old protocol support
+	eth62 = 62 // Constant to check for new protocol support
 )
 
 var (
@@ -324,16 +322,8 @@ func (d *Downloader) syncWithPeer(p *peer, hash common.Hash, td *big.Int) (err e
 
 	glog.V(logger.Debug).Infof("Synchronizing with the network using: %s, eth/%d", p.id, p.version)
 	switch p.version {
-	case eth60:
-		// Old eth/60 version, use reverse hash retrieval algorithm
-		if err = d.fetchHashes60(p, hash); err != nil {
-			return err
-		}
-		if err = d.fetchBlocks60(); err != nil {
-			return err
-		}
 	case eth61:
-		// New eth/61, use forward, concurrent hash and block retrieval algorithm
+		// Old eth/61, use forward, concurrent hash and block retrieval algorithm
 		number, err := d.findAncestor(p)
 		if err != nil {
 			return err
@@ -355,8 +345,6 @@ func (d *Downloader) syncWithPeer(p *peer, hash common.Hash, td *big.Int) (err e
 		glog.V(logger.Error).Infof("Unsupported eth protocol: %d", p.version)
 		return errBadPeer
 	}
-	glog.V(logger.Debug).Infoln("Synchronization completed")
-
 	return nil
 }
 
@@ -385,299 +373,6 @@ func (d *Downloader) Terminate() {
 	d.cancel()
 }
 
-// fetchHashes60 starts retrieving hashes backwards from a specific peer and hash,
-// up until it finds a common ancestor. If the source peer times out, alternative
-// ones are tried for continuation.
-func (d *Downloader) fetchHashes60(p *peer, h common.Hash) error {
-	var (
-		start  = time.Now()
-		active = p             // active peer will help determine the current active peer
-		head   = common.Hash{} // common and last hash
-
-		timeout     = time.NewTimer(0)                // timer to dump a non-responsive active peer
-		attempted   = make(map[string]bool)           // attempted peers will help with retries
-		crossTicker = time.NewTicker(crossCheckCycle) // ticker to periodically check expired cross checks
-	)
-	defer crossTicker.Stop()
-	defer timeout.Stop()
-
-	glog.V(logger.Debug).Infof("Downloading hashes (%x) from %s", h[:4], p.id)
-	<-timeout.C // timeout channel should be initially empty.
-
-	getHashes := func(from common.Hash) {
-		go active.getRelHashes(from)
-		timeout.Reset(hashTTL)
-	}
-
-	// Add the hash to the queue, and start hash retrieval.
-	d.queue.Insert([]common.Hash{h}, false)
-	getHashes(h)
-
-	attempted[p.id] = true
-	for finished := false; !finished; {
-		select {
-		case <-d.cancelCh:
-			return errCancelHashFetch
-
-		case hashPack := <-d.hashCh:
-			// Make sure the active peer is giving us the hashes
-			if hashPack.peerId != active.id {
-				glog.V(logger.Debug).Infof("Received hashes from incorrect peer(%s)", hashPack.peerId)
-				break
-			}
-			timeout.Stop()
-
-			// Make sure the peer actually gave something valid
-			if len(hashPack.hashes) == 0 {
-				glog.V(logger.Debug).Infof("Peer (%s) responded with empty hash set", active.id)
-				return errEmptyHashSet
-			}
-			for index, hash := range hashPack.hashes {
-				if d.banned.Has(hash) {
-					glog.V(logger.Debug).Infof("Peer (%s) sent a known invalid chain", active.id)
-
-					d.queue.Insert(hashPack.hashes[:index+1], false)
-					if err := d.banBlocks(active.id, hash); err != nil {
-						glog.V(logger.Debug).Infof("Failed to ban batch of blocks: %v", err)
-					}
-					return errInvalidChain
-				}
-			}
-			// Determine if we're done fetching hashes (queue up all pending), and continue if not done
-			done, index := false, 0
-			for index, head = range hashPack.hashes {
-				if d.hasBlock(head) || d.queue.GetBlock(head) != nil {
-					glog.V(logger.Debug).Infof("Found common hash %x", head[:4])
-					hashPack.hashes = hashPack.hashes[:index]
-					done = true
-					break
-				}
-			}
-			// Insert all the new hashes, but only continue if got something useful
-			inserts := d.queue.Insert(hashPack.hashes, false)
-			if len(inserts) == 0 && !done {
-				glog.V(logger.Debug).Infof("Peer (%s) responded with stale hashes", active.id)
-				return errBadPeer
-			}
-			if !done {
-				// Check that the peer is not stalling the sync
-				if len(inserts) < MinHashFetch {
-					return errStallingPeer
-				}
-				// Try and fetch a random block to verify the hash batch
-				// Skip the last hash as the cross check races with the next hash fetch
-				cross := rand.Intn(len(inserts) - 1)
-				origin, parent := inserts[cross], inserts[cross+1]
-				glog.V(logger.Detail).Infof("Cross checking (%s) with %x/%x", active.id, origin, parent)
-
-				d.checks[origin] = &crossCheck{
-					expire: time.Now().Add(blockSoftTTL),
-					parent: parent,
-				}
-				go active.getBlocks([]common.Hash{origin})
-
-				// Also fetch a fresh batch of hashes
-				getHashes(head)
-				continue
-			}
-			// We're done, prepare the download cache and proceed pulling the blocks
-			offset := uint64(0)
-			if block := d.getBlock(head); block != nil {
-				offset = block.NumberU64() + 1
-			}
-			d.queue.Prepare(offset)
-			finished = true
-
-		case blockPack := <-d.blockCh:
-			// Cross check the block with the random verifications
-			if blockPack.peerId != active.id || len(blockPack.blocks) != 1 {
-				continue
-			}
-			block := blockPack.blocks[0]
-			if check, ok := d.checks[block.Hash()]; ok {
-				if block.ParentHash() != check.parent {
-					return errCrossCheckFailed
-				}
-				delete(d.checks, block.Hash())
-			}
-
-		case <-crossTicker.C:
-			// Iterate over all the cross checks and fail the hash chain if they're not verified
-			for hash, check := range d.checks {
-				if time.Now().After(check.expire) {
-					glog.V(logger.Debug).Infof("Cross check timeout for %x", hash)
-					return errCrossCheckFailed
-				}
-			}
-
-		case <-timeout.C:
-			glog.V(logger.Debug).Infof("Peer (%s) didn't respond in time for hash request", p.id)
-
-			var p *peer // p will be set if a peer can be found
-			// Attempt to find a new peer by checking inclusion of peers best hash in our
-			// already fetched hash list. This can't guarantee 100% correctness but does
-			// a fair job. This is always either correct or false incorrect.
-			for _, peer := range d.peers.AllPeers() {
-				if d.queue.Has(peer.head) && !attempted[peer.id] {
-					p = peer
-					break
-				}
-			}
-			// if all peers have been tried, abort the process entirely or if the hash is
-			// the zero hash.
-			if p == nil || (head == common.Hash{}) {
-				return errTimeout
-			}
-			// set p to the active peer. this will invalidate any hashes that may be returned
-			// by our previous (delayed) peer.
-			active = p
-			getHashes(head)
-			glog.V(logger.Debug).Infof("Hash fetching switched to new peer(%s)", p.id)
-		}
-	}
-	glog.V(logger.Debug).Infof("Downloaded hashes (%d) in %v", d.queue.Pending(), time.Since(start))
-
-	return nil
-}
-
-// fetchBlocks60 iteratively downloads the entire schedules block-chain, taking
-// any available peers, reserving a chunk of blocks for each, wait for delivery
-// and periodically checking for timeouts.
-func (d *Downloader) fetchBlocks60() error {
-	glog.V(logger.Debug).Infoln("Downloading", d.queue.Pending(), "block(s)")
-	start := time.Now()
-
-	// Start a ticker to continue throttled downloads and check for bad peers
-	ticker := time.NewTicker(20 * time.Millisecond)
-	defer ticker.Stop()
-
-out:
-	for {
-		select {
-		case <-d.cancelCh:
-			return errCancelBlockFetch
-
-		case <-d.hashCh:
-			// Out of bounds hashes received, ignore them
-
-		case blockPack := <-d.blockCh:
-			// Short circuit if it's a stale cross check
-			if len(blockPack.blocks) == 1 {
-				block := blockPack.blocks[0]
-				if _, ok := d.checks[block.Hash()]; ok {
-					delete(d.checks, block.Hash())
-					break
-				}
-			}
-			// If the peer was previously banned and failed to deliver it's pack
-			// in a reasonable time frame, ignore it's message.
-			if peer := d.peers.Peer(blockPack.peerId); peer != nil {
-				// Deliver the received chunk of blocks, and demote in case of errors
-				err := d.queue.Deliver(blockPack.peerId, blockPack.blocks)
-				switch err {
-				case nil:
-					// If no blocks were delivered, demote the peer (need the delivery above)
-					if len(blockPack.blocks) == 0 {
-						peer.Demote()
-						peer.SetIdle()
-						glog.V(logger.Detail).Infof("%s: no blocks delivered", peer)
-						break
-					}
-					// All was successful, promote the peer and potentially start processing
-					peer.Promote()
-					peer.SetIdle()
-					glog.V(logger.Detail).Infof("%s: delivered %d blocks", peer, len(blockPack.blocks))
-					go d.process()
-
-				case errInvalidChain:
-					// The hash chain is invalid (blocks are not ordered properly), abort
-					return err
-
-				case errNoFetchesPending:
-					// Peer probably timed out with its delivery but came through
-					// in the end, demote, but allow to to pull from this peer.
-					peer.Demote()
-					peer.SetIdle()
-					glog.V(logger.Detail).Infof("%s: out of bound delivery", peer)
-
-				case errStaleDelivery:
-					// Delivered something completely else than requested, usually
-					// caused by a timeout and delivery during a new sync cycle.
-					// Don't set it to idle as the original request should still be
-					// in flight.
-					peer.Demote()
-					glog.V(logger.Detail).Infof("%s: stale delivery", peer)
-
-				default:
-					// Peer did something semi-useful, demote but keep it around
-					peer.Demote()
-					peer.SetIdle()
-					glog.V(logger.Detail).Infof("%s: delivery partially failed: %v", peer, err)
-					go d.process()
-				}
-			}
-
-		case <-ticker.C:
-			// Short circuit if we lost all our peers
-			if d.peers.Len() == 0 {
-				return errNoPeers
-			}
-			// Check for block request timeouts and demote the responsible peers
-			badPeers := d.queue.Expire(blockHardTTL)
-			for _, pid := range badPeers {
-				if peer := d.peers.Peer(pid); peer != nil {
-					peer.Demote()
-					glog.V(logger.Detail).Infof("%s: block delivery timeout", peer)
-				}
-			}
-			// If there are unrequested hashes left start fetching from the available peers
-			if d.queue.Pending() > 0 {
-				// Throttle the download if block cache is full and waiting processing
-				if d.queue.Throttle() {
-					break
-				}
-				// Send a download request to all idle peers, until throttled
-				idlePeers := d.peers.IdlePeers()
-				for _, peer := range idlePeers {
-					// Short circuit if throttling activated since above
-					if d.queue.Throttle() {
-						break
-					}
-					// Get a possible chunk. If nil is returned no chunk
-					// could be returned due to no hashes available.
-					request := d.queue.Reserve(peer, peer.Capacity())
-					if request == nil {
-						continue
-					}
-					if glog.V(logger.Detail) {
-						glog.Infof("%s: requesting %d blocks", peer, len(request.Hashes))
-					}
-					// Fetch the chunk and check for error. If the peer was somehow
-					// already fetching a chunk due to a bug, it will be returned to
-					// the queue
-					if err := peer.Fetch(request); err != nil {
-						glog.V(logger.Error).Infof("Peer %s received double work", peer.id)
-						d.queue.Cancel(request)
-					}
-				}
-				// Make sure that we have peers available for fetching. If all peers have been tried
-				// and all failed throw an error
-				if d.queue.InFlight() == 0 {
-					return errPeersUnavailable
-				}
-
-			} else if d.queue.InFlight() == 0 {
-				// When there are no more queue and no more in flight, We can
-				// safely assume we're done. Another part of the process will  check
-				// for parent errors and will re-request anything that's missing
-				break out
-			}
-		}
-	}
-	glog.V(logger.Detail).Infoln("Downloaded block(s) in", time.Since(start))
-	return nil
-}
-
 // findAncestor tries to locate the common ancestor block of the local chain and
 // a remote peers blockchain. In the general case when our node was in sync and
 // on the correct chain, checking the top N blocks should already get us a match.
@@ -1023,92 +718,6 @@ func (d *Downloader) fetchBlocks(from uint64) error {
 	}
 }
 
-// banBlocks retrieves a batch of blocks from a peer feeding us invalid hashes,
-// and bans the head of the retrieved batch.
-//
-// This method only fetches one single batch as the goal is not ban an entire
-// (potentially long) invalid chain - wasting a lot of time in the meanwhile -,
-// but rather to gradually build up a blacklist if the peer keeps reconnecting.
-func (d *Downloader) banBlocks(peerId string, head common.Hash) error {
-	glog.V(logger.Debug).Infof("Banning a batch out of %d blocks from %s", d.queue.Pending(), peerId)
-
-	// Ask the peer being banned for a batch of blocks from the banning point
-	peer := d.peers.Peer(peerId)
-	if peer == nil {
-		return nil
-	}
-	request := d.queue.Reserve(peer, MaxBlockFetch)
-	if request == nil {
-		return nil
-	}
-	if err := peer.Fetch(request); err != nil {
-		return err
-	}
-	// Wait a bit for the reply to arrive, and ban if done so
-	timeout := time.After(blockHardTTL)
-	for {
-		select {
-		case <-d.cancelCh:
-			return errCancelBlockFetch
-
-		case <-timeout:
-			return errTimeout
-
-		case <-d.hashCh:
-			// Out of bounds hashes received, ignore them
-
-		case blockPack := <-d.blockCh:
-			blocks := blockPack.blocks
-
-			// Short circuit if it's a stale cross check
-			if len(blocks) == 1 {
-				block := blocks[0]
-				if _, ok := d.checks[block.Hash()]; ok {
-					delete(d.checks, block.Hash())
-					break
-				}
-			}
-			// Short circuit if it's not from the peer being banned
-			if blockPack.peerId != peerId {
-				break
-			}
-			// Short circuit if no blocks were returned
-			if len(blocks) == 0 {
-				return errors.New("no blocks returned to ban")
-			}
-			// Reconstruct the original chain order and ensure we're banning the correct blocks
-			types.BlockBy(types.Number).Sort(blocks)
-			if bytes.Compare(blocks[0].Hash().Bytes(), head.Bytes()) != 0 {
-				return errors.New("head block not the banned one")
-			}
-			index := 0
-			for _, block := range blocks[1:] {
-				if bytes.Compare(block.ParentHash().Bytes(), blocks[index].Hash().Bytes()) != 0 {
-					break
-				}
-				index++
-			}
-			// Ban the head hash and phase out any excess
-			d.banned.Add(blocks[index].Hash())
-			for d.banned.Size() > maxBannedHashes {
-				var evacuate common.Hash
-
-				d.banned.Each(func(item interface{}) bool {
-					// Skip any hard coded bans
-					if core.BadHashes[item.(common.Hash)] {
-						return true
-					}
-					evacuate = item.(common.Hash)
-					return false
-				})
-				d.banned.Remove(evacuate)
-			}
-			glog.V(logger.Debug).Infof("Banned %d blocks from: %s", index+1, peerId)
-			return nil
-		}
-	}
-}
-
 // process takes blocks from the queue and tries to import them into the chain.
 //
 // The algorithmic flow is as follows: