aboutsummaryrefslogtreecommitdiffstats
path: root/eth/downloader
diff options
context:
space:
mode:
authorobscuren <geffobscura@gmail.com>2015-05-03 22:09:10 +0800
committerobscuren <geffobscura@gmail.com>2015-05-03 22:27:03 +0800
commit1470b22e9051f48fbbeb136cc4c0be0877e9f9a7 (patch)
tree8b88f38edd9cf61073bee7253a2a8033042b25ae /eth/downloader
parentba2236fa513e06603d3fa2a6d721be3879d7f50e (diff)
downloadgo-tangerine-1470b22e9051f48fbbeb136cc4c0be0877e9f9a7.tar
go-tangerine-1470b22e9051f48fbbeb136cc4c0be0877e9f9a7.tar.gz
go-tangerine-1470b22e9051f48fbbeb136cc4c0be0877e9f9a7.tar.bz2
go-tangerine-1470b22e9051f48fbbeb136cc4c0be0877e9f9a7.tar.lz
go-tangerine-1470b22e9051f48fbbeb136cc4c0be0877e9f9a7.tar.xz
go-tangerine-1470b22e9051f48fbbeb136cc4c0be0877e9f9a7.tar.zst
go-tangerine-1470b22e9051f48fbbeb136cc4c0be0877e9f9a7.zip
downloader: hash downloading recovery
If a peer fails to respond (disconnect, etc) during hash downloading switch to a different peer which has it's current_hash in the queue's peer set.
Diffstat (limited to 'eth/downloader')
-rw-r--r--eth/downloader/downloader.go73
-rw-r--r--eth/downloader/downloader_test.go27
2 files changed, 71 insertions, 29 deletions
diff --git a/eth/downloader/downloader.go b/eth/downloader/downloader.go
index a484ce0a7..15f4cb0a3 100644
--- a/eth/downloader/downloader.go
+++ b/eth/downloader/downloader.go
@@ -53,6 +53,11 @@ type syncPack struct {
ignoreInitial bool
}
+type hashPack struct {
+ peerId string
+ hashes []common.Hash
+}
+
type Downloader struct {
mu sync.RWMutex
queue *queue
@@ -69,7 +74,7 @@ type Downloader struct {
// Channels
newPeerCh chan *peer
- hashCh chan []common.Hash
+ hashCh chan hashPack
blockCh chan blockPack
}
@@ -80,7 +85,7 @@ func New(hasBlock hashCheckFn, getBlock getBlockFn) *Downloader {
hasBlock: hasBlock,
getBlock: getBlock,
newPeerCh: make(chan *peer, 1),
- hashCh: make(chan []common.Hash, 1),
+ hashCh: make(chan hashPack, 1),
blockCh: make(chan blockPack, 1),
}
@@ -235,15 +240,15 @@ func (d *Downloader) getFromPeer(p *peer, hash common.Hash, ignoreInitial bool)
}
// XXX Make synchronous
-func (d *Downloader) startFetchingHashes(p *peer, hash common.Hash, ignoreInitial bool) error {
+func (d *Downloader) startFetchingHashes(p *peer, h common.Hash, ignoreInitial bool) error {
atomic.StoreInt32(&d.fetchingHashes, 1)
defer atomic.StoreInt32(&d.fetchingHashes, 0)
- if d.queue.has(hash) {
+ if d.queue.has(h) {
return errAlreadyInPool
}
- glog.V(logger.Debug).Infof("Downloading hashes (%x) from %s", hash.Bytes()[:4], p.id)
+ glog.V(logger.Debug).Infof("Downloading hashes (%x) from %s", h[:4], p.id)
start := time.Now()
@@ -251,22 +256,34 @@ func (d *Downloader) startFetchingHashes(p *peer, hash common.Hash, ignoreInitia
// In such circumstances we don't need to download the block so don't add it to the queue.
if !ignoreInitial {
// Add the hash to the queue first
- d.queue.hashPool.Add(hash)
+ d.queue.hashPool.Add(h)
}
// Get the first batch of hashes
- p.getHashes(hash)
+ p.getHashes(h)
- failureResponseTimer := time.NewTimer(hashTtl)
+ var (
+ failureResponseTimer = time.NewTimer(hashTtl)
+ attemptedPeers = make(map[string]bool) // attempted peers will help with retries
+ activePeer = p // active peer will help determine the current active peer
+ hash common.Hash // common and last hash
+ )
+ attemptedPeers[p.id] = true
out:
for {
select {
- case hashes := <-d.hashCh:
+ case hashPack := <-d.hashCh:
+ // make sure the active peer is giving us the hashes
+ if hashPack.peerId != activePeer.id {
+ glog.V(logger.Debug).Infof("Received hashes from incorrect peer(%s)\n", hashPack.peerId)
+ break
+ }
+
failureResponseTimer.Reset(hashTtl)
var (
- done bool // determines whether we're done fetching hashes (i.e. common hash found)
- hash common.Hash // current and common hash
+ hashes = hashPack.hashes
+ done bool // determines whether we're done fetching hashes (i.e. common hash found)
)
hashSet := set.New()
for _, hash = range hashes {
@@ -283,13 +300,13 @@ out:
// Add hashes to the chunk set
if len(hashes) == 0 { // Make sure the peer actually gave you something valid
- glog.V(logger.Debug).Infof("Peer (%s) responded with empty hash set\n", p.id)
+ glog.V(logger.Debug).Infof("Peer (%s) responded with empty hash set\n", activePeer.id)
d.queue.reset()
return errEmptyHashSet
} else if !done { // Check if we're done fetching
// Get the next set of hashes
- p.getHashes(hashes[len(hashes)-1])
+ activePeer.getHashes(hash)
} else { // we're done
// The offset of the queue is determined by the highest known block
var offset int
@@ -303,12 +320,30 @@ out:
}
case <-failureResponseTimer.C:
glog.V(logger.Debug).Infof("Peer (%s) didn't respond in time for hash request\n", p.id)
- // TODO instead of reseting the queue select a new peer from which we can start downloading hashes.
- // 1. check for peer's best hash to be included in the current hash set;
- // 2. resume from last point (hashes[len(hashes)-1]) using the newly selected peer.
- d.queue.reset()
- return errTimeout
+ 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 id, peer := range d.peers {
+ if d.queue.hashPool.Has(peer.recentHash) && !attemptedPeers[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 || (hash == common.Hash{}) {
+ d.queue.reset()
+ return errTimeout
+ }
+
+ // set p to the active peer. this will invalidate any hashes that may be returned
+ // by our previous (delayed) peer.
+ activePeer = p
+ p.getHashes(hash)
+ glog.V(logger.Debug).Infof("Hash fetching switched to new peer(%s)\n", p.id)
}
}
glog.V(logger.Detail).Infof("Downloaded hashes (%d) in %v\n", d.queue.hashPool.Size(), time.Since(start))
@@ -454,7 +489,7 @@ func (d *Downloader) AddHashes(id string, hashes []common.Hash) error {
glog.Infof("adding %d (T=%d) hashes [ %x / %x ] from: %s\n", len(hashes), d.queue.hashPool.Size(), from[:4], to[:4], id)
}
- d.hashCh <- hashes
+ d.hashCh <- hashPack{id, hashes}
return nil
}
diff --git a/eth/downloader/downloader_test.go b/eth/downloader/downloader_test.go
index fe68ea914..872ea02eb 100644
--- a/eth/downloader/downloader_test.go
+++ b/eth/downloader/downloader_test.go
@@ -42,12 +42,13 @@ func createBlocksFromHashes(hashes []common.Hash) map[common.Hash]*types.Block {
}
type downloadTester struct {
- downloader *Downloader
- hashes []common.Hash
- blocks map[common.Hash]*types.Block
- t *testing.T
- pcount int
- done chan bool
+ downloader *Downloader
+ hashes []common.Hash
+ blocks map[common.Hash]*types.Block
+ t *testing.T
+ pcount int
+ done chan bool
+ activePeerId string
}
func newTester(t *testing.T, hashes []common.Hash, blocks map[common.Hash]*types.Block) *downloadTester {
@@ -58,6 +59,11 @@ func newTester(t *testing.T, hashes []common.Hash, blocks map[common.Hash]*types
return tester
}
+func (dl *downloadTester) sync(peerId string, hash common.Hash) error {
+ dl.activePeerId = peerId
+ return dl.downloader.Synchronise(peerId, hash)
+}
+
func (dl *downloadTester) hasBlock(hash common.Hash) bool {
if knownHash == hash {
return true
@@ -70,7 +76,7 @@ func (dl *downloadTester) getBlock(hash common.Hash) *types.Block {
}
func (dl *downloadTester) getHashes(hash common.Hash) error {
- dl.downloader.hashCh <- dl.hashes
+ dl.downloader.AddHashes(dl.activePeerId, dl.hashes)
return nil
}
@@ -115,8 +121,9 @@ func TestDownload(t *testing.T) {
tester.newPeer("peer2", big.NewInt(0), common.Hash{})
tester.badBlocksPeer("peer3", big.NewInt(0), common.Hash{})
tester.badBlocksPeer("peer4", big.NewInt(0), common.Hash{})
+ tester.activePeerId = "peer1"
- err := tester.downloader.Synchronise("peer1", hashes[0])
+ err := tester.sync("peer1", hashes[0])
if err != nil {
t.Error("download error", err)
}
@@ -139,7 +146,7 @@ func TestMissing(t *testing.T) {
hashes = append(extraHashes, hashes[:len(hashes)-1]...)
tester.newPeer("peer2", big.NewInt(0), common.Hash{})
- err := tester.downloader.Synchronise("peer1", hashes[0])
+ err := tester.sync("peer1", hashes[0])
if err != nil {
t.Error("download error", err)
}
@@ -164,7 +171,7 @@ func TestTaking(t *testing.T) {
tester.badBlocksPeer("peer3", big.NewInt(0), common.Hash{})
tester.badBlocksPeer("peer4", big.NewInt(0), common.Hash{})
- err := tester.downloader.Synchronise("peer1", hashes[0])
+ err := tester.sync("peer1", hashes[0])
if err != nil {
t.Error("download error", err)
}