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-rw-r--r--eth/downloader/downloader.go397
1 files changed, 376 insertions, 21 deletions
diff --git a/eth/downloader/downloader.go b/eth/downloader/downloader.go
index 1b31f5dbd..b4154c166 100644
--- a/eth/downloader/downloader.go
+++ b/eth/downloader/downloader.go
@@ -19,6 +19,11 @@ import (
"gopkg.in/fatih/set.v0"
)
+const (
+ eth60 = 60 // Constant to check for old protocol support
+ eth61 = 61 // Constant to check for new protocol support
+)
+
var (
MinHashFetch = 512 // Minimum amount of hashes to not consider a peer stalling
MaxHashFetch = 2048 // Amount of hashes to be fetched per retrieval request
@@ -58,6 +63,9 @@ type hashCheckFn func(common.Hash) bool
// blockRetrievalFn is a callback type for retrieving a block from the local chain.
type blockRetrievalFn func(common.Hash) *types.Block
+// headRetrievalFn is a callback type for retrieving the head block from the local chain.
+type headRetrievalFn func() *types.Block
+
// chainInsertFn is a callback type to insert a batch of blocks into the local chain.
type chainInsertFn func(types.Blocks) (int, error)
@@ -98,6 +106,7 @@ type Downloader struct {
// Callbacks
hasBlock hashCheckFn // Checks if a block is present in the chain
getBlock blockRetrievalFn // Retrieves a block from the chain
+ headBlock headRetrievalFn // Retrieves the head block from the chain
insertChain chainInsertFn // Injects a batch of blocks into the chain
dropPeer peerDropFn // Drops a peer for misbehaving
@@ -109,8 +118,9 @@ type Downloader struct {
// Channels
newPeerCh chan *peer
- hashCh chan hashPack
- blockCh chan blockPack
+ hashCh chan hashPack // Channel receiving inbound hashes
+ blockCh chan blockPack // Channel receiving inbound blocks
+ processCh chan bool // Channel to signal the block fetcher of new or finished work
cancelCh chan struct{} // Channel to cancel mid-flight syncs
cancelLock sync.RWMutex // Lock to protect the cancel channel in delivers
@@ -123,7 +133,7 @@ type Block struct {
}
// New creates a new downloader to fetch hashes and blocks from remote peers.
-func New(mux *event.TypeMux, hasBlock hashCheckFn, getBlock blockRetrievalFn, insertChain chainInsertFn, dropPeer peerDropFn) *Downloader {
+func New(mux *event.TypeMux, hasBlock hashCheckFn, getBlock blockRetrievalFn, headBlock headRetrievalFn, insertChain chainInsertFn, dropPeer peerDropFn) *Downloader {
// Create the base downloader
downloader := &Downloader{
mux: mux,
@@ -131,11 +141,13 @@ func New(mux *event.TypeMux, hasBlock hashCheckFn, getBlock blockRetrievalFn, in
peers: newPeerSet(),
hasBlock: hasBlock,
getBlock: getBlock,
+ headBlock: headBlock,
insertChain: insertChain,
dropPeer: dropPeer,
newPeerCh: make(chan *peer, 1),
hashCh: make(chan hashPack, 1),
blockCh: make(chan blockPack, 1),
+ processCh: make(chan bool, 1),
}
// Inject all the known bad hashes
downloader.banned = set.New()
@@ -175,7 +187,7 @@ func (d *Downloader) Synchronising() bool {
// RegisterPeer injects a new download peer into the set of block source to be
// used for fetching hashes and blocks from.
-func (d *Downloader) RegisterPeer(id string, version int, head common.Hash, getHashes hashFetcherFn, getBlocks blockFetcherFn) error {
+func (d *Downloader) RegisterPeer(id string, version int, head common.Hash, getRelHashes relativeHashFetcherFn, getAbsHashes absoluteHashFetcherFn, getBlocks blockFetcherFn) error {
// If the peer wants to send a banned hash, reject
if d.banned.Has(head) {
glog.V(logger.Debug).Infoln("Register rejected, head hash banned:", id)
@@ -183,7 +195,7 @@ func (d *Downloader) RegisterPeer(id string, version int, head common.Hash, getH
}
// Otherwise try to construct and register the peer
glog.V(logger.Detail).Infoln("Registering peer", id)
- if err := d.peers.Register(newPeer(id, version, head, getHashes, getBlocks)); err != nil {
+ if err := d.peers.Register(newPeer(id, version, head, getRelHashes, getAbsHashes, getBlocks)); err != nil {
glog.V(logger.Error).Infoln("Register failed:", err)
return err
}
@@ -289,12 +301,38 @@ func (d *Downloader) syncWithPeer(p *peer, hash common.Hash) (err error) {
}
}()
- glog.V(logger.Debug).Infoln("Synchronizing with the network using:", p.id)
- if err = d.fetchHashes(p, hash); err != nil {
- return err
- }
- if err = d.fetchBlocks(); err != nil {
- return err
+ 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
+ number, err := d.findAncestor(p)
+ if err != nil {
+ return err
+ }
+ errc := make(chan error, 2)
+ go func() { errc <- d.fetchHashes(p, number+1) }()
+ go func() { errc <- d.fetchBlocks(number + 1) }()
+
+ // If any fetcher fails, cancel the other
+ if err := <-errc; err != nil {
+ d.cancel()
+ <-errc
+ return err
+ }
+ return <-errc
+
+ default:
+ // Something very wrong, stop right here
+ glog.V(logger.Error).Infof("Unsupported eth protocol: %d", p.version)
+ return errBadPeer
}
glog.V(logger.Debug).Infoln("Synchronization completed")
@@ -326,10 +364,10 @@ func (d *Downloader) Terminate() {
d.cancel()
}
-// fetchHahes starts retrieving hashes backwards from a specific peer and hash,
+// 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) fetchHashes(p *peer, h common.Hash) error {
+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
@@ -346,12 +384,12 @@ func (d *Downloader) fetchHashes(p *peer, h common.Hash) error {
<-timeout.C // timeout channel should be initially empty.
getHashes := func(from common.Hash) {
- go active.getHashes(from)
+ go active.getRelHashes(from)
timeout.Reset(hashTTL)
}
// Add the hash to the queue, and start hash retrieval.
- d.queue.Insert([]common.Hash{h})
+ d.queue.Insert([]common.Hash{h}, false)
getHashes(h)
attempted[p.id] = true
@@ -377,7 +415,7 @@ func (d *Downloader) fetchHashes(p *peer, h common.Hash) error {
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])
+ 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)
}
@@ -395,7 +433,7 @@ func (d *Downloader) fetchHashes(p *peer, h common.Hash) error {
}
}
// Insert all the new hashes, but only continue if got something useful
- inserts := d.queue.Insert(hashPack.hashes)
+ 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
@@ -422,9 +460,9 @@ func (d *Downloader) fetchHashes(p *peer, h common.Hash) error {
continue
}
// We're done, prepare the download cache and proceed pulling the blocks
- offset := 0
+ offset := uint64(0)
if block := d.getBlock(head); block != nil {
- offset = int(block.NumberU64() + 1)
+ offset = block.NumberU64() + 1
}
d.queue.Prepare(offset)
finished = true
@@ -481,10 +519,10 @@ func (d *Downloader) fetchHashes(p *peer, h common.Hash) error {
return nil
}
-// fetchBlocks iteratively downloads the entire schedules block-chain, taking
+// 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) fetchBlocks() error {
+func (d *Downloader) fetchBlocks60() error {
glog.V(logger.Debug).Infoln("Downloading", d.queue.Pending(), "block(s)")
start := time.Now()
@@ -619,6 +657,323 @@ out:
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.
+// In the rare scenario when we ended up on a long soft fork (i.e. none of the
+// head blocks match), we do a binary search to find the common ancestor.
+func (d *Downloader) findAncestor(p *peer) (uint64, error) {
+ glog.V(logger.Debug).Infof("%v: looking for common ancestor", p)
+
+ // Request out head blocks to short circuit ancestor location
+ head := d.headBlock().NumberU64()
+ from := int64(head) - int64(MaxHashFetch)
+ if from < 0 {
+ from = 0
+ }
+ go p.getAbsHashes(uint64(from), MaxHashFetch)
+
+ // Wait for the remote response to the head fetch
+ number, hash := uint64(0), common.Hash{}
+ timeout := time.After(hashTTL)
+
+ for finished := false; !finished; {
+ select {
+ case <-d.cancelCh:
+ return 0, errCancelHashFetch
+
+ case hashPack := <-d.hashCh:
+ // Discard anything not from the origin peer
+ if hashPack.peerId != p.id {
+ glog.V(logger.Debug).Infof("Received hashes from incorrect peer(%s)", hashPack.peerId)
+ break
+ }
+ // Make sure the peer actually gave something valid
+ hashes := hashPack.hashes
+ if len(hashes) == 0 {
+ glog.V(logger.Debug).Infof("%v: empty head hash set", p)
+ return 0, errEmptyHashSet
+ }
+ // Check if a common ancestor was found
+ finished = true
+ for i := len(hashes) - 1; i >= 0; i-- {
+ if d.hasBlock(hashes[i]) {
+ number, hash = uint64(from)+uint64(i), hashes[i]
+ break
+ }
+ }
+
+ case <-d.blockCh:
+ // Out of bounds blocks received, ignore them
+
+ case <-timeout:
+ glog.V(logger.Debug).Infof("%v: head hash timeout", p)
+ return 0, errTimeout
+ }
+ }
+ // If the head fetch already found an ancestor, return
+ if !common.EmptyHash(hash) {
+ glog.V(logger.Debug).Infof("%v: common ancestor: #%d [%x]", p, number, hash[:4])
+ return number, nil
+ }
+ // Ancestor not found, we need to binary search over our chain
+ start, end := uint64(0), head
+ for start+1 < end {
+ // Split our chain interval in two, and request the hash to cross check
+ check := (start + end) / 2
+
+ timeout := time.After(hashTTL)
+ go p.getAbsHashes(uint64(check), 1)
+
+ // Wait until a reply arrives to this request
+ for arrived := false; !arrived; {
+ select {
+ case <-d.cancelCh:
+ return 0, errCancelHashFetch
+
+ case hashPack := <-d.hashCh:
+ // Discard anything not from the origin peer
+ if hashPack.peerId != p.id {
+ glog.V(logger.Debug).Infof("Received hashes from incorrect peer(%s)", hashPack.peerId)
+ break
+ }
+ // Make sure the peer actually gave something valid
+ hashes := hashPack.hashes
+ if len(hashes) != 1 {
+ glog.V(logger.Debug).Infof("%v: invalid search hash set (%d)", p, len(hashes))
+ return 0, errBadPeer
+ }
+ arrived = true
+
+ // Modify the search interval based on the response
+ block := d.getBlock(hashes[0])
+ if block == nil {
+ end = check
+ break
+ }
+ if block.NumberU64() != check {
+ glog.V(logger.Debug).Infof("%v: non requested hash #%d [%x], instead of #%d", p, block.NumberU64(), block.Hash().Bytes()[:4], check)
+ return 0, errBadPeer
+ }
+ start = check
+
+ case <-d.blockCh:
+ // Out of bounds blocks received, ignore them
+
+ case <-timeout:
+ glog.V(logger.Debug).Infof("%v: search hash timeout", p)
+ return 0, errTimeout
+ }
+ }
+ }
+ return start, nil
+}
+
+// fetchHashes keeps retrieving hashes from the requested number, until no more
+// are returned, potentially throttling on the way.
+func (d *Downloader) fetchHashes(p *peer, from uint64) error {
+ glog.V(logger.Debug).Infof("%v: downloading hashes from #%d", p, from)
+
+ // Create a timeout timer, and the associated hash fetcher
+ timeout := time.NewTimer(0) // timer to dump a non-responsive active peer
+ <-timeout.C // timeout channel should be initially empty
+ defer timeout.Stop()
+
+ getHashes := func(from uint64) {
+ go p.getAbsHashes(from, MaxHashFetch)
+ timeout.Reset(hashTTL)
+ }
+ // Start pulling hashes, until all are exhausted
+ getHashes(from)
+ for {
+ select {
+ case <-d.cancelCh:
+ return errCancelHashFetch
+
+ case hashPack := <-d.hashCh:
+ // Make sure the active peer is giving us the hashes
+ if hashPack.peerId != p.id {
+ glog.V(logger.Debug).Infof("Received hashes from incorrect peer(%s)", hashPack.peerId)
+ break
+ }
+ timeout.Stop()
+
+ // If no more hashes are inbound, notify the block fetcher and return
+ if len(hashPack.hashes) == 0 {
+ glog.V(logger.Debug).Infof("%v: no available hashes", p)
+
+ select {
+ case d.processCh <- false:
+ case <-d.cancelCh:
+ }
+ return nil
+ }
+ // Otherwise insert all the new hashes, aborting in case of junk
+ inserts := d.queue.Insert(hashPack.hashes, true)
+ if len(inserts) != len(hashPack.hashes) {
+ glog.V(logger.Debug).Infof("%v: stale hashes", p)
+ return errBadPeer
+ }
+ // Notify the block fetcher of new hashes, and continue fetching
+ select {
+ case d.processCh <- true:
+ default:
+ }
+ from += uint64(len(hashPack.hashes))
+ getHashes(from)
+
+ case <-timeout.C:
+ glog.V(logger.Debug).Infof("%v: hash request timed out", p)
+ return errTimeout
+ }
+ }
+}
+
+// fetchBlocks iteratively downloads the scheduled hashes, taking any available
+// peers, reserving a chunk of blocks for each, waiting for delivery and also
+// periodically checking for timeouts.
+func (d *Downloader) fetchBlocks(from uint64) error {
+ glog.V(logger.Debug).Infof("Downloading blocks from #%d", from)
+ defer glog.V(logger.Debug).Infof("Block download terminated")
+
+ // Create a timeout timer for scheduling expiration tasks
+ ticker := time.NewTicker(100 * time.Millisecond)
+ defer ticker.Stop()
+
+ update := make(chan struct{}, 1)
+
+ // Prepare the queue and fetch blocks until the hash fetcher's done
+ d.queue.Prepare(from)
+ finished := false
+
+ for {
+ select {
+ case <-d.cancelCh:
+ return errCancelBlockFetch
+
+ case blockPack := <-d.blockCh:
+ // 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()
+ }
+ }
+ // Blocks arrived, try to update the progress
+ select {
+ case update <- struct{}{}:
+ default:
+ }
+
+ case cont := <-d.processCh:
+ // The hash fetcher sent a continuation flag, check if it's done
+ if !cont {
+ finished = true
+ }
+ // Hashes arrive, try to update the progress
+ select {
+ case update <- struct{}{}:
+ default:
+ }
+
+ case <-ticker.C:
+ // Sanity check update the progress
+ select {
+ case update <- struct{}{}:
+ default:
+ }
+
+ case <-update:
+ // 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
+ for _, pid := range d.queue.Expire(blockHardTTL) {
+ if peer := d.peers.Peer(pid); peer != nil {
+ peer.Demote()
+ glog.V(logger.Detail).Infof("%s: block delivery timeout", peer)
+ }
+ }
+ // If there's noting more to fetch, wait or terminate
+ if d.queue.Pending() == 0 {
+ if d.queue.InFlight() == 0 && finished {
+ glog.V(logger.Debug).Infof("Block fetching completed")
+ return nil
+ }
+ break
+ }
+ // Send a download request to all idle peers, until throttled
+ for _, peer := range d.peers.IdlePeers() {
+ // Short circuit if throttling activated
+ if d.queue.Throttle() {
+ break
+ }
+ // Reserve a chunk of hashes for a peer. A nil can mean either that
+ // no more hashes are available, or that the peer is known not to
+ // have them.
+ 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 make sure any errors return the hashes to the queue
+ if err := peer.Fetch(request); err != nil {
+ glog.V(logger.Error).Infof("%v: fetch failed, rescheduling", peer)
+ 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.Throttle() && d.queue.InFlight() == 0 {
+ return errPeersUnavailable
+ }
+ }
+ }
+}
+
// banBlocks retrieves a batch of blocks from a peer feeding us invalid hashes,
// and bans the head of the retrieved batch.
//
generated by cgit (git 2.34.1) at 2024-11-14 09:41:34 +0800