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authorSonic <sonic@dexon.org>2018-11-09 14:47:57 +0800
committerWei-Ning Huang <w@dexon.org>2019-04-09 21:32:53 +0800
commit089257a3da86184c66f666ff8e119e1ca7850357 (patch)
treef40fa6d9d4760a6171e88999deb33ebb2f546ad1 /dex/fetcher
parent09f24f35eff61861c21b854a648c3afec579ff47 (diff)
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dex: copy fetcher and downloader from eth
Diffstat (limited to 'dex/fetcher')
-rw-r--r--dex/fetcher/fetcher.go736
-rw-r--r--dex/fetcher/fetcher_test.go790
-rw-r--r--dex/fetcher/metrics.go43
3 files changed, 1569 insertions, 0 deletions
diff --git a/dex/fetcher/fetcher.go b/dex/fetcher/fetcher.go
new file mode 100644
index 000000000..f6807b5a5
--- /dev/null
+++ b/dex/fetcher/fetcher.go
@@ -0,0 +1,736 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// Package fetcher contains the block announcement based synchronisation.
+package fetcher
+
+import (
+ "errors"
+ "math/rand"
+ "time"
+
+ "github.com/dexon-foundation/dexon/common"
+ "github.com/dexon-foundation/dexon/common/prque"
+ "github.com/dexon-foundation/dexon/consensus"
+ "github.com/dexon-foundation/dexon/core/types"
+ "github.com/dexon-foundation/dexon/log"
+)
+
+const (
+ arriveTimeout = 500 * time.Millisecond // Time allowance before an announced block is explicitly requested
+ gatherSlack = 100 * time.Millisecond // Interval used to collate almost-expired announces with fetches
+ fetchTimeout = 5 * time.Second // Maximum allotted time to return an explicitly requested block
+ maxUncleDist = 7 // Maximum allowed backward distance from the chain head
+ maxQueueDist = 32 // Maximum allowed distance from the chain head to queue
+ hashLimit = 256 // Maximum number of unique blocks a peer may have announced
+ blockLimit = 64 // Maximum number of unique blocks a peer may have delivered
+)
+
+var (
+ errTerminated = errors.New("terminated")
+)
+
+// blockRetrievalFn is a callback type for retrieving a block from the local chain.
+type blockRetrievalFn func(common.Hash) *types.Block
+
+// headerRequesterFn is a callback type for sending a header retrieval request.
+type headerRequesterFn func(common.Hash) error
+
+// bodyRequesterFn is a callback type for sending a body retrieval request.
+type bodyRequesterFn func([]common.Hash) error
+
+// headerVerifierFn is a callback type to verify a block's header for fast propagation.
+type headerVerifierFn func(header *types.Header) error
+
+// blockBroadcasterFn is a callback type for broadcasting a block to connected peers.
+type blockBroadcasterFn func(block *types.Block, propagate bool)
+
+// chainHeightFn is a callback type to retrieve the current chain height.
+type chainHeightFn func() uint64
+
+// chainInsertFn is a callback type to insert a batch of blocks into the local chain.
+type chainInsertFn func(types.Blocks) (int, error)
+
+// peerDropFn is a callback type for dropping a peer detected as malicious.
+type peerDropFn func(id string)
+
+// announce is the hash notification of the availability of a new block in the
+// network.
+type announce struct {
+ hash common.Hash // Hash of the block being announced
+ number uint64 // Number of the block being announced (0 = unknown | old protocol)
+ header *types.Header // Header of the block partially reassembled (new protocol)
+ time time.Time // Timestamp of the announcement
+
+ origin string // Identifier of the peer originating the notification
+
+ fetchHeader headerRequesterFn // Fetcher function to retrieve the header of an announced block
+ fetchBodies bodyRequesterFn // Fetcher function to retrieve the body of an announced block
+}
+
+// headerFilterTask represents a batch of headers needing fetcher filtering.
+type headerFilterTask struct {
+ peer string // The source peer of block headers
+ headers []*types.Header // Collection of headers to filter
+ time time.Time // Arrival time of the headers
+}
+
+// bodyFilterTask represents a batch of block bodies (transactions and uncles)
+// needing fetcher filtering.
+type bodyFilterTask struct {
+ peer string // The source peer of block bodies
+ transactions [][]*types.Transaction // Collection of transactions per block bodies
+ uncles [][]*types.Header // Collection of uncles per block bodies
+ time time.Time // Arrival time of the blocks' contents
+}
+
+// inject represents a schedules import operation.
+type inject struct {
+ origin string
+ block *types.Block
+}
+
+// Fetcher is responsible for accumulating block announcements from various peers
+// and scheduling them for retrieval.
+type Fetcher struct {
+ // Various event channels
+ notify chan *announce
+ inject chan *inject
+
+ blockFilter chan chan []*types.Block
+ headerFilter chan chan *headerFilterTask
+ bodyFilter chan chan *bodyFilterTask
+
+ done chan common.Hash
+ quit chan struct{}
+
+ // Announce states
+ announces map[string]int // Per peer announce counts to prevent memory exhaustion
+ announced map[common.Hash][]*announce // Announced blocks, scheduled for fetching
+ fetching map[common.Hash]*announce // Announced blocks, currently fetching
+ fetched map[common.Hash][]*announce // Blocks with headers fetched, scheduled for body retrieval
+ completing map[common.Hash]*announce // Blocks with headers, currently body-completing
+
+ // Block cache
+ queue *prque.Prque // Queue containing the import operations (block number sorted)
+ queues map[string]int // Per peer block counts to prevent memory exhaustion
+ queued map[common.Hash]*inject // Set of already queued blocks (to dedupe imports)
+
+ // Callbacks
+ getBlock blockRetrievalFn // Retrieves a block from the local chain
+ verifyHeader headerVerifierFn // Checks if a block's headers have a valid proof of work
+ broadcastBlock blockBroadcasterFn // Broadcasts a block to connected peers
+ chainHeight chainHeightFn // Retrieves the current chain's height
+ insertChain chainInsertFn // Injects a batch of blocks into the chain
+ dropPeer peerDropFn // Drops a peer for misbehaving
+
+ // Testing hooks
+ announceChangeHook func(common.Hash, bool) // Method to call upon adding or deleting a hash from the announce list
+ queueChangeHook func(common.Hash, bool) // Method to call upon adding or deleting a block from the import queue
+ fetchingHook func([]common.Hash) // Method to call upon starting a block (eth/61) or header (eth/62) fetch
+ completingHook func([]common.Hash) // Method to call upon starting a block body fetch (eth/62)
+ importedHook func(*types.Block) // Method to call upon successful block import (both eth/61 and eth/62)
+}
+
+// New creates a block fetcher to retrieve blocks based on hash announcements.
+func New(getBlock blockRetrievalFn, verifyHeader headerVerifierFn, broadcastBlock blockBroadcasterFn, chainHeight chainHeightFn, insertChain chainInsertFn, dropPeer peerDropFn) *Fetcher {
+ return &Fetcher{
+ notify: make(chan *announce),
+ inject: make(chan *inject),
+ blockFilter: make(chan chan []*types.Block),
+ headerFilter: make(chan chan *headerFilterTask),
+ bodyFilter: make(chan chan *bodyFilterTask),
+ done: make(chan common.Hash),
+ quit: make(chan struct{}),
+ announces: make(map[string]int),
+ announced: make(map[common.Hash][]*announce),
+ fetching: make(map[common.Hash]*announce),
+ fetched: make(map[common.Hash][]*announce),
+ completing: make(map[common.Hash]*announce),
+ queue: prque.New(nil),
+ queues: make(map[string]int),
+ queued: make(map[common.Hash]*inject),
+ getBlock: getBlock,
+ verifyHeader: verifyHeader,
+ broadcastBlock: broadcastBlock,
+ chainHeight: chainHeight,
+ insertChain: insertChain,
+ dropPeer: dropPeer,
+ }
+}
+
+// Start boots up the announcement based synchroniser, accepting and processing
+// hash notifications and block fetches until termination requested.
+func (f *Fetcher) Start() {
+ go f.loop()
+}
+
+// Stop terminates the announcement based synchroniser, canceling all pending
+// operations.
+func (f *Fetcher) Stop() {
+ close(f.quit)
+}
+
+// Notify announces the fetcher of the potential availability of a new block in
+// the network.
+func (f *Fetcher) Notify(peer string, hash common.Hash, number uint64, time time.Time,
+ headerFetcher headerRequesterFn, bodyFetcher bodyRequesterFn) error {
+ block := &announce{
+ hash: hash,
+ number: number,
+ time: time,
+ origin: peer,
+ fetchHeader: headerFetcher,
+ fetchBodies: bodyFetcher,
+ }
+ select {
+ case f.notify <- block:
+ return nil
+ case <-f.quit:
+ return errTerminated
+ }
+}
+
+// Enqueue tries to fill gaps the fetcher's future import queue.
+func (f *Fetcher) Enqueue(peer string, block *types.Block) error {
+ op := &inject{
+ origin: peer,
+ block: block,
+ }
+ select {
+ case f.inject <- op:
+ return nil
+ case <-f.quit:
+ return errTerminated
+ }
+}
+
+// FilterHeaders extracts all the headers that were explicitly requested by the fetcher,
+// returning those that should be handled differently.
+func (f *Fetcher) FilterHeaders(peer string, headers []*types.Header, time time.Time) []*types.Header {
+ log.Trace("Filtering headers", "peer", peer, "headers", len(headers))
+
+ // Send the filter channel to the fetcher
+ filter := make(chan *headerFilterTask)
+
+ select {
+ case f.headerFilter <- filter:
+ case <-f.quit:
+ return nil
+ }
+ // Request the filtering of the header list
+ select {
+ case filter <- &headerFilterTask{peer: peer, headers: headers, time: time}:
+ case <-f.quit:
+ return nil
+ }
+ // Retrieve the headers remaining after filtering
+ select {
+ case task := <-filter:
+ return task.headers
+ case <-f.quit:
+ return nil
+ }
+}
+
+// FilterBodies extracts all the block bodies that were explicitly requested by
+// the fetcher, returning those that should be handled differently.
+func (f *Fetcher) FilterBodies(peer string, transactions [][]*types.Transaction, uncles [][]*types.Header, time time.Time) ([][]*types.Transaction, [][]*types.Header) {
+ log.Trace("Filtering bodies", "peer", peer, "txs", len(transactions), "uncles", len(uncles))
+
+ // Send the filter channel to the fetcher
+ filter := make(chan *bodyFilterTask)
+
+ select {
+ case f.bodyFilter <- filter:
+ case <-f.quit:
+ return nil, nil
+ }
+ // Request the filtering of the body list
+ select {
+ case filter <- &bodyFilterTask{peer: peer, transactions: transactions, uncles: uncles, time: time}:
+ case <-f.quit:
+ return nil, nil
+ }
+ // Retrieve the bodies remaining after filtering
+ select {
+ case task := <-filter:
+ return task.transactions, task.uncles
+ case <-f.quit:
+ return nil, nil
+ }
+}
+
+// Loop is the main fetcher loop, checking and processing various notification
+// events.
+func (f *Fetcher) loop() {
+ // Iterate the block fetching until a quit is requested
+ fetchTimer := time.NewTimer(0)
+ completeTimer := time.NewTimer(0)
+
+ for {
+ // Clean up any expired block fetches
+ for hash, announce := range f.fetching {
+ if time.Since(announce.time) > fetchTimeout {
+ f.forgetHash(hash)
+ }
+ }
+ // Import any queued blocks that could potentially fit
+ height := f.chainHeight()
+ for !f.queue.Empty() {
+ op := f.queue.PopItem().(*inject)
+ hash := op.block.Hash()
+ if f.queueChangeHook != nil {
+ f.queueChangeHook(hash, false)
+ }
+ // If too high up the chain or phase, continue later
+ number := op.block.NumberU64()
+ if number > height+1 {
+ f.queue.Push(op, -int64(number))
+ if f.queueChangeHook != nil {
+ f.queueChangeHook(hash, true)
+ }
+ break
+ }
+ // Otherwise if fresh and still unknown, try and import
+ if number+maxUncleDist < height || f.getBlock(hash) != nil {
+ f.forgetBlock(hash)
+ continue
+ }
+ f.insert(op.origin, op.block)
+ }
+ // Wait for an outside event to occur
+ select {
+ case <-f.quit:
+ // Fetcher terminating, abort all operations
+ return
+
+ case notification := <-f.notify:
+ // A block was announced, make sure the peer isn't DOSing us
+ propAnnounceInMeter.Mark(1)
+
+ count := f.announces[notification.origin] + 1
+ if count > hashLimit {
+ log.Debug("Peer exceeded outstanding announces", "peer", notification.origin, "limit", hashLimit)
+ propAnnounceDOSMeter.Mark(1)
+ break
+ }
+ // If we have a valid block number, check that it's potentially useful
+ if notification.number > 0 {
+ if dist := int64(notification.number) - int64(f.chainHeight()); dist < -maxUncleDist || dist > maxQueueDist {
+ log.Debug("Peer discarded announcement", "peer", notification.origin, "number", notification.number, "hash", notification.hash, "distance", dist)
+ propAnnounceDropMeter.Mark(1)
+ break
+ }
+ }
+ // All is well, schedule the announce if block's not yet downloading
+ if _, ok := f.fetching[notification.hash]; ok {
+ break
+ }
+ if _, ok := f.completing[notification.hash]; ok {
+ break
+ }
+ f.announces[notification.origin] = count
+ f.announced[notification.hash] = append(f.announced[notification.hash], notification)
+ if f.announceChangeHook != nil && len(f.announced[notification.hash]) == 1 {
+ f.announceChangeHook(notification.hash, true)
+ }
+ if len(f.announced) == 1 {
+ f.rescheduleFetch(fetchTimer)
+ }
+
+ case op := <-f.inject:
+ // A direct block insertion was requested, try and fill any pending gaps
+ propBroadcastInMeter.Mark(1)
+ f.enqueue(op.origin, op.block)
+
+ case hash := <-f.done:
+ // A pending import finished, remove all traces of the notification
+ f.forgetHash(hash)
+ f.forgetBlock(hash)
+
+ case <-fetchTimer.C:
+ // At least one block's timer ran out, check for needing retrieval
+ request := make(map[string][]common.Hash)
+
+ for hash, announces := range f.announced {
+ if time.Since(announces[0].time) > arriveTimeout-gatherSlack {
+ // Pick a random peer to retrieve from, reset all others
+ announce := announces[rand.Intn(len(announces))]
+ f.forgetHash(hash)
+
+ // If the block still didn't arrive, queue for fetching
+ if f.getBlock(hash) == nil {
+ request[announce.origin] = append(request[announce.origin], hash)
+ f.fetching[hash] = announce
+ }
+ }
+ }
+ // Send out all block header requests
+ for peer, hashes := range request {
+ log.Trace("Fetching scheduled headers", "peer", peer, "list", hashes)
+
+ // Create a closure of the fetch and schedule in on a new thread
+ fetchHeader, hashes := f.fetching[hashes[0]].fetchHeader, hashes
+ go func() {
+ if f.fetchingHook != nil {
+ f.fetchingHook(hashes)
+ }
+ for _, hash := range hashes {
+ headerFetchMeter.Mark(1)
+ fetchHeader(hash) // Suboptimal, but protocol doesn't allow batch header retrievals
+ }
+ }()
+ }
+ // Schedule the next fetch if blocks are still pending
+ f.rescheduleFetch(fetchTimer)
+
+ case <-completeTimer.C:
+ // At least one header's timer ran out, retrieve everything
+ request := make(map[string][]common.Hash)
+
+ for hash, announces := range f.fetched {
+ // Pick a random peer to retrieve from, reset all others
+ announce := announces[rand.Intn(len(announces))]
+ f.forgetHash(hash)
+
+ // If the block still didn't arrive, queue for completion
+ if f.getBlock(hash) == nil {
+ request[announce.origin] = append(request[announce.origin], hash)
+ f.completing[hash] = announce
+ }
+ }
+ // Send out all block body requests
+ for peer, hashes := range request {
+ log.Trace("Fetching scheduled bodies", "peer", peer, "list", hashes)
+
+ // Create a closure of the fetch and schedule in on a new thread
+ if f.completingHook != nil {
+ f.completingHook(hashes)
+ }
+ bodyFetchMeter.Mark(int64(len(hashes)))
+ go f.completing[hashes[0]].fetchBodies(hashes)
+ }
+ // Schedule the next fetch if blocks are still pending
+ f.rescheduleComplete(completeTimer)
+
+ case filter := <-f.headerFilter:
+ // Headers arrived from a remote peer. Extract those that were explicitly
+ // requested by the fetcher, and return everything else so it's delivered
+ // to other parts of the system.
+ var task *headerFilterTask
+ select {
+ case task = <-filter:
+ case <-f.quit:
+ return
+ }
+ headerFilterInMeter.Mark(int64(len(task.headers)))
+
+ // Split the batch of headers into unknown ones (to return to the caller),
+ // known incomplete ones (requiring body retrievals) and completed blocks.
+ unknown, incomplete, complete := []*types.Header{}, []*announce{}, []*types.Block{}
+ for _, header := range task.headers {
+ hash := header.Hash()
+
+ // Filter fetcher-requested headers from other synchronisation algorithms
+ if announce := f.fetching[hash]; announce != nil && announce.origin == task.peer && f.fetched[hash] == nil && f.completing[hash] == nil && f.queued[hash] == nil {
+ // If the delivered header does not match the promised number, drop the announcer
+ if header.Number.Uint64() != announce.number {
+ log.Trace("Invalid block number fetched", "peer", announce.origin, "hash", header.Hash(), "announced", announce.number, "provided", header.Number)
+ f.dropPeer(announce.origin)
+ f.forgetHash(hash)
+ continue
+ }
+ // Only keep if not imported by other means
+ if f.getBlock(hash) == nil {
+ announce.header = header
+ announce.time = task.time
+
+ // If the block is empty (header only), short circuit into the final import queue
+ if header.TxHash == types.DeriveSha(types.Transactions{}) && header.UncleHash == types.CalcUncleHash([]*types.Header{}) {
+ log.Trace("Block empty, skipping body retrieval", "peer", announce.origin, "number", header.Number, "hash", header.Hash())
+
+ block := types.NewBlockWithHeader(header)
+ block.ReceivedAt = task.time
+
+ complete = append(complete, block)
+ f.completing[hash] = announce
+ continue
+ }
+ // Otherwise add to the list of blocks needing completion
+ incomplete = append(incomplete, announce)
+ } else {
+ log.Trace("Block already imported, discarding header", "peer", announce.origin, "number", header.Number, "hash", header.Hash())
+ f.forgetHash(hash)
+ }
+ } else {
+ // Fetcher doesn't know about it, add to the return list
+ unknown = append(unknown, header)
+ }
+ }
+ headerFilterOutMeter.Mark(int64(len(unknown)))
+ select {
+ case filter <- &headerFilterTask{headers: unknown, time: task.time}:
+ case <-f.quit:
+ return
+ }
+ // Schedule the retrieved headers for body completion
+ for _, announce := range incomplete {
+ hash := announce.header.Hash()
+ if _, ok := f.completing[hash]; ok {
+ continue
+ }
+ f.fetched[hash] = append(f.fetched[hash], announce)
+ if len(f.fetched) == 1 {
+ f.rescheduleComplete(completeTimer)
+ }
+ }
+ // Schedule the header-only blocks for import
+ for _, block := range complete {
+ if announce := f.completing[block.Hash()]; announce != nil {
+ f.enqueue(announce.origin, block)
+ }
+ }
+
+ case filter := <-f.bodyFilter:
+ // Block bodies arrived, extract any explicitly requested blocks, return the rest
+ var task *bodyFilterTask
+ select {
+ case task = <-filter:
+ case <-f.quit:
+ return
+ }
+ bodyFilterInMeter.Mark(int64(len(task.transactions)))
+
+ blocks := []*types.Block{}
+ for i := 0; i < len(task.transactions) && i < len(task.uncles); i++ {
+ // Match up a body to any possible completion request
+ matched := false
+
+ for hash, announce := range f.completing {
+ if f.queued[hash] == nil {
+ txnHash := types.DeriveSha(types.Transactions(task.transactions[i]))
+ uncleHash := types.CalcUncleHash(task.uncles[i])
+
+ if txnHash == announce.header.TxHash && uncleHash == announce.header.UncleHash && announce.origin == task.peer {
+ // Mark the body matched, reassemble if still unknown
+ matched = true
+
+ if f.getBlock(hash) == nil {
+ block := types.NewBlockWithHeader(announce.header).WithBody(task.transactions[i], task.uncles[i])
+ block.ReceivedAt = task.time
+
+ blocks = append(blocks, block)
+ } else {
+ f.forgetHash(hash)
+ }
+ }
+ }
+ }
+ if matched {
+ task.transactions = append(task.transactions[:i], task.transactions[i+1:]...)
+ task.uncles = append(task.uncles[:i], task.uncles[i+1:]...)
+ i--
+ continue
+ }
+ }
+
+ bodyFilterOutMeter.Mark(int64(len(task.transactions)))
+ select {
+ case filter <- task:
+ case <-f.quit:
+ return
+ }
+ // Schedule the retrieved blocks for ordered import
+ for _, block := range blocks {
+ if announce := f.completing[block.Hash()]; announce != nil {
+ f.enqueue(announce.origin, block)
+ }
+ }
+ }
+ }
+}
+
+// rescheduleFetch resets the specified fetch timer to the next announce timeout.
+func (f *Fetcher) rescheduleFetch(fetch *time.Timer) {
+ // Short circuit if no blocks are announced
+ if len(f.announced) == 0 {
+ return
+ }
+ // Otherwise find the earliest expiring announcement
+ earliest := time.Now()
+ for _, announces := range f.announced {
+ if earliest.After(announces[0].time) {
+ earliest = announces[0].time
+ }
+ }
+ fetch.Reset(arriveTimeout - time.Since(earliest))
+}
+
+// rescheduleComplete resets the specified completion timer to the next fetch timeout.
+func (f *Fetcher) rescheduleComplete(complete *time.Timer) {
+ // Short circuit if no headers are fetched
+ if len(f.fetched) == 0 {
+ return
+ }
+ // Otherwise find the earliest expiring announcement
+ earliest := time.Now()
+ for _, announces := range f.fetched {
+ if earliest.After(announces[0].time) {
+ earliest = announces[0].time
+ }
+ }
+ complete.Reset(gatherSlack - time.Since(earliest))
+}
+
+// enqueue schedules a new future import operation, if the block to be imported
+// has not yet been seen.
+func (f *Fetcher) enqueue(peer string, block *types.Block) {
+ hash := block.Hash()
+
+ // Ensure the peer isn't DOSing us
+ count := f.queues[peer] + 1
+ if count > blockLimit {
+ log.Debug("Discarded propagated block, exceeded allowance", "peer", peer, "number", block.Number(), "hash", hash, "limit", blockLimit)
+ propBroadcastDOSMeter.Mark(1)
+ f.forgetHash(hash)
+ return
+ }
+ // Discard any past or too distant blocks
+ if dist := int64(block.NumberU64()) - int64(f.chainHeight()); dist < -maxUncleDist || dist > maxQueueDist {
+ log.Debug("Discarded propagated block, too far away", "peer", peer, "number", block.Number(), "hash", hash, "distance", dist)
+ propBroadcastDropMeter.Mark(1)
+ f.forgetHash(hash)
+ return
+ }
+ // Schedule the block for future importing
+ if _, ok := f.queued[hash]; !ok {
+ op := &inject{
+ origin: peer,
+ block: block,
+ }
+ f.queues[peer] = count
+ f.queued[hash] = op
+ f.queue.Push(op, -int64(block.NumberU64()))
+ if f.queueChangeHook != nil {
+ f.queueChangeHook(op.block.Hash(), true)
+ }
+ log.Debug("Queued propagated block", "peer", peer, "number", block.Number(), "hash", hash, "queued", f.queue.Size())
+ }
+}
+
+// insert spawns a new goroutine to run a block insertion into the chain. If the
+// block's number is at the same height as the current import phase, it updates
+// the phase states accordingly.
+func (f *Fetcher) insert(peer string, block *types.Block) {
+ hash := block.Hash()
+
+ // Run the import on a new thread
+ log.Debug("Importing propagated block", "peer", peer, "number", block.Number(), "hash", hash)
+ go func() {
+ defer func() { f.done <- hash }()
+
+ // If the parent's unknown, abort insertion
+ parent := f.getBlock(block.ParentHash())
+ if parent == nil {
+ log.Debug("Unknown parent of propagated block", "peer", peer, "number", block.Number(), "hash", hash, "parent", block.ParentHash())
+ return
+ }
+ // Quickly validate the header and propagate the block if it passes
+ switch err := f.verifyHeader(block.Header()); err {
+ case nil:
+ // All ok, quickly propagate to our peers
+ propBroadcastOutTimer.UpdateSince(block.ReceivedAt)
+ go f.broadcastBlock(block, true)
+
+ case consensus.ErrFutureBlock:
+ // Weird future block, don't fail, but neither propagate
+
+ default:
+ // Something went very wrong, drop the peer
+ log.Debug("Propagated block verification failed", "peer", peer, "number", block.Number(), "hash", hash, "err", err)
+ f.dropPeer(peer)
+ return
+ }
+ // Run the actual import and log any issues
+ if _, err := f.insertChain(types.Blocks{block}); err != nil {
+ log.Debug("Propagated block import failed", "peer", peer, "number", block.Number(), "hash", hash, "err", err)
+ return
+ }
+ // If import succeeded, broadcast the block
+ propAnnounceOutTimer.UpdateSince(block.ReceivedAt)
+ go f.broadcastBlock(block, false)
+
+ // Invoke the testing hook if needed
+ if f.importedHook != nil {
+ f.importedHook(block)
+ }
+ }()
+}
+
+// forgetHash removes all traces of a block announcement from the fetcher's
+// internal state.
+func (f *Fetcher) forgetHash(hash common.Hash) {
+ // Remove all pending announces and decrement DOS counters
+ for _, announce := range f.announced[hash] {
+ f.announces[announce.origin]--
+ if f.announces[announce.origin] == 0 {
+ delete(f.announces, announce.origin)
+ }
+ }
+ delete(f.announced, hash)
+ if f.announceChangeHook != nil {
+ f.announceChangeHook(hash, false)
+ }
+ // Remove any pending fetches and decrement the DOS counters
+ if announce := f.fetching[hash]; announce != nil {
+ f.announces[announce.origin]--
+ if f.announces[announce.origin] == 0 {
+ delete(f.announces, announce.origin)
+ }
+ delete(f.fetching, hash)
+ }
+
+ // Remove any pending completion requests and decrement the DOS counters
+ for _, announce := range f.fetched[hash] {
+ f.announces[announce.origin]--
+ if f.announces[announce.origin] == 0 {
+ delete(f.announces, announce.origin)
+ }
+ }
+ delete(f.fetched, hash)
+
+ // Remove any pending completions and decrement the DOS counters
+ if announce := f.completing[hash]; announce != nil {
+ f.announces[announce.origin]--
+ if f.announces[announce.origin] == 0 {
+ delete(f.announces, announce.origin)
+ }
+ delete(f.completing, hash)
+ }
+}
+
+// forgetBlock removes all traces of a queued block from the fetcher's internal
+// state.
+func (f *Fetcher) forgetBlock(hash common.Hash) {
+ if insert := f.queued[hash]; insert != nil {
+ f.queues[insert.origin]--
+ if f.queues[insert.origin] == 0 {
+ delete(f.queues, insert.origin)
+ }
+ delete(f.queued, hash)
+ }
+}
diff --git a/dex/fetcher/fetcher_test.go b/dex/fetcher/fetcher_test.go
new file mode 100644
index 000000000..24611a8a0
--- /dev/null
+++ b/dex/fetcher/fetcher_test.go
@@ -0,0 +1,790 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package fetcher
+
+import (
+ "errors"
+ "math/big"
+ "sync"
+ "sync/atomic"
+ "testing"
+ "time"
+
+ "github.com/dexon-foundation/dexon/common"
+ "github.com/dexon-foundation/dexon/consensus/ethash"
+ "github.com/dexon-foundation/dexon/core"
+ "github.com/dexon-foundation/dexon/core/types"
+ "github.com/dexon-foundation/dexon/crypto"
+ "github.com/dexon-foundation/dexon/ethdb"
+ "github.com/dexon-foundation/dexon/params"
+)
+
+var (
+ testdb = ethdb.NewMemDatabase()
+ testKey, _ = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
+ testAddress = crypto.PubkeyToAddress(testKey.PublicKey)
+ genesis = core.GenesisBlockForTesting(testdb, testAddress, big.NewInt(1000000000))
+ unknownBlock = types.NewBlock(&types.Header{GasLimit: params.GenesisGasLimit}, nil, nil, nil)
+)
+
+// makeChain creates a chain of n blocks starting at and including parent.
+// the returned hash chain is ordered head->parent. In addition, every 3rd block
+// contains a transaction and every 5th an uncle to allow testing correct block
+// reassembly.
+func makeChain(n int, seed byte, parent *types.Block) ([]common.Hash, map[common.Hash]*types.Block) {
+ blocks, _ := core.GenerateChain(params.TestChainConfig, parent, ethash.NewFaker(), testdb, n, func(i int, block *core.BlockGen) {
+ block.SetCoinbase(common.Address{seed})
+
+ // If the block number is multiple of 3, send a bonus transaction to the miner
+ if parent == genesis && i%3 == 0 {
+ signer := types.MakeSigner(params.TestChainConfig, block.Number())
+ tx, err := types.SignTx(types.NewTransaction(block.TxNonce(testAddress), common.Address{seed}, big.NewInt(1000), params.TxGas, nil, nil), signer, testKey)
+ if err != nil {
+ panic(err)
+ }
+ block.AddTx(tx)
+ }
+ // If the block number is a multiple of 5, add a bonus uncle to the block
+ if i%5 == 0 {
+ block.AddUncle(&types.Header{ParentHash: block.PrevBlock(i - 1).Hash(), Number: big.NewInt(int64(i - 1))})
+ }
+ })
+ hashes := make([]common.Hash, n+1)
+ hashes[len(hashes)-1] = parent.Hash()
+ blockm := make(map[common.Hash]*types.Block, n+1)
+ blockm[parent.Hash()] = parent
+ for i, b := range blocks {
+ hashes[len(hashes)-i-2] = b.Hash()
+ blockm[b.Hash()] = b
+ }
+ return hashes, blockm
+}
+
+// fetcherTester is a test simulator for mocking out local block chain.
+type fetcherTester struct {
+ fetcher *Fetcher
+
+ hashes []common.Hash // Hash chain belonging to the tester
+ blocks map[common.Hash]*types.Block // Blocks belonging to the tester
+ drops map[string]bool // Map of peers dropped by the fetcher
+
+ lock sync.RWMutex
+}
+
+// newTester creates a new fetcher test mocker.
+func newTester() *fetcherTester {
+ tester := &fetcherTester{
+ hashes: []common.Hash{genesis.Hash()},
+ blocks: map[common.Hash]*types.Block{genesis.Hash(): genesis},
+ drops: make(map[string]bool),
+ }
+ tester.fetcher = New(tester.getBlock, tester.verifyHeader, tester.broadcastBlock, tester.chainHeight, tester.insertChain, tester.dropPeer)
+ tester.fetcher.Start()
+
+ return tester
+}
+
+// getBlock retrieves a block from the tester's block chain.
+func (f *fetcherTester) getBlock(hash common.Hash) *types.Block {
+ f.lock.RLock()
+ defer f.lock.RUnlock()
+
+ return f.blocks[hash]
+}
+
+// verifyHeader is a nop placeholder for the block header verification.
+func (f *fetcherTester) verifyHeader(header *types.Header) error {
+ return nil
+}
+
+// broadcastBlock is a nop placeholder for the block broadcasting.
+func (f *fetcherTester) broadcastBlock(block *types.Block, propagate bool) {
+}
+
+// chainHeight retrieves the current height (block number) of the chain.
+func (f *fetcherTester) chainHeight() uint64 {
+ f.lock.RLock()
+ defer f.lock.RUnlock()
+
+ return f.blocks[f.hashes[len(f.hashes)-1]].NumberU64()
+}
+
+// insertChain injects a new blocks into the simulated chain.
+func (f *fetcherTester) insertChain(blocks types.Blocks) (int, error) {
+ f.lock.Lock()
+ defer f.lock.Unlock()
+
+ for i, block := range blocks {
+ // Make sure the parent in known
+ if _, ok := f.blocks[block.ParentHash()]; !ok {
+ return i, errors.New("unknown parent")
+ }
+ // Discard any new blocks if the same height already exists
+ if block.NumberU64() <= f.blocks[f.hashes[len(f.hashes)-1]].NumberU64() {
+ return i, nil
+ }
+ // Otherwise build our current chain
+ f.hashes = append(f.hashes, block.Hash())
+ f.blocks[block.Hash()] = block
+ }
+ return 0, nil
+}
+
+// dropPeer is an emulator for the peer removal, simply accumulating the various
+// peers dropped by the fetcher.
+func (f *fetcherTester) dropPeer(peer string) {
+ f.lock.Lock()
+ defer f.lock.Unlock()
+
+ f.drops[peer] = true
+}
+
+// makeHeaderFetcher retrieves a block header fetcher associated with a simulated peer.
+func (f *fetcherTester) makeHeaderFetcher(peer string, blocks map[common.Hash]*types.Block, drift time.Duration) headerRequesterFn {
+ closure := make(map[common.Hash]*types.Block)
+ for hash, block := range blocks {
+ closure[hash] = block
+ }
+ // Create a function that return a header from the closure
+ return func(hash common.Hash) error {
+ // Gather the blocks to return
+ headers := make([]*types.Header, 0, 1)
+ if block, ok := closure[hash]; ok {
+ headers = append(headers, block.Header())
+ }
+ // Return on a new thread
+ go f.fetcher.FilterHeaders(peer, headers, time.Now().Add(drift))
+
+ return nil
+ }
+}
+
+// makeBodyFetcher retrieves a block body fetcher associated with a simulated peer.
+func (f *fetcherTester) makeBodyFetcher(peer string, blocks map[common.Hash]*types.Block, drift time.Duration) bodyRequesterFn {
+ closure := make(map[common.Hash]*types.Block)
+ for hash, block := range blocks {
+ closure[hash] = block
+ }
+ // Create a function that returns blocks from the closure
+ return func(hashes []common.Hash) error {
+ // Gather the block bodies to return
+ transactions := make([][]*types.Transaction, 0, len(hashes))
+ uncles := make([][]*types.Header, 0, len(hashes))
+
+ for _, hash := range hashes {
+ if block, ok := closure[hash]; ok {
+ transactions = append(transactions, block.Transactions())
+ uncles = append(uncles, block.Uncles())
+ }
+ }
+ // Return on a new thread
+ go f.fetcher.FilterBodies(peer, transactions, uncles, time.Now().Add(drift))
+
+ return nil
+ }
+}
+
+// verifyFetchingEvent verifies that one single event arrive on a fetching channel.
+func verifyFetchingEvent(t *testing.T, fetching chan []common.Hash, arrive bool) {
+ if arrive {
+ select {
+ case <-fetching:
+ case <-time.After(time.Second):
+ t.Fatalf("fetching timeout")
+ }
+ } else {
+ select {
+ case <-fetching:
+ t.Fatalf("fetching invoked")
+ case <-time.After(10 * time.Millisecond):
+ }
+ }
+}
+
+// verifyCompletingEvent verifies that one single event arrive on an completing channel.
+func verifyCompletingEvent(t *testing.T, completing chan []common.Hash, arrive bool) {
+ if arrive {
+ select {
+ case <-completing:
+ case <-time.After(time.Second):
+ t.Fatalf("completing timeout")
+ }
+ } else {
+ select {
+ case <-completing:
+ t.Fatalf("completing invoked")
+ case <-time.After(10 * time.Millisecond):
+ }
+ }
+}
+
+// verifyImportEvent verifies that one single event arrive on an import channel.
+func verifyImportEvent(t *testing.T, imported chan *types.Block, arrive bool) {
+ if arrive {
+ select {
+ case <-imported:
+ case <-time.After(time.Second):
+ t.Fatalf("import timeout")
+ }
+ } else {
+ select {
+ case <-imported:
+ t.Fatalf("import invoked")
+ case <-time.After(10 * time.Millisecond):
+ }
+ }
+}
+
+// verifyImportCount verifies that exactly count number of events arrive on an
+// import hook channel.
+func verifyImportCount(t *testing.T, imported chan *types.Block, count int) {
+ for i := 0; i < count; i++ {
+ select {
+ case <-imported:
+ case <-time.After(time.Second):
+ t.Fatalf("block %d: import timeout", i+1)
+ }
+ }
+ verifyImportDone(t, imported)
+}
+
+// verifyImportDone verifies that no more events are arriving on an import channel.
+func verifyImportDone(t *testing.T, imported chan *types.Block) {
+ select {
+ case <-imported:
+ t.Fatalf("extra block imported")
+ case <-time.After(50 * time.Millisecond):
+ }
+}
+
+// Tests that a fetcher accepts block announcements and initiates retrievals for
+// them, successfully importing into the local chain.
+func TestSequentialAnnouncements62(t *testing.T) { testSequentialAnnouncements(t, 62) }
+func TestSequentialAnnouncements63(t *testing.T) { testSequentialAnnouncements(t, 63) }
+func TestSequentialAnnouncements64(t *testing.T) { testSequentialAnnouncements(t, 64) }
+
+func testSequentialAnnouncements(t *testing.T, protocol int) {
+ // Create a chain of blocks to import
+ targetBlocks := 4 * hashLimit
+ hashes, blocks := makeChain(targetBlocks, 0, genesis)
+
+ tester := newTester()
+ headerFetcher := tester.makeHeaderFetcher("valid", blocks, -gatherSlack)
+ bodyFetcher := tester.makeBodyFetcher("valid", blocks, 0)
+
+ // Iteratively announce blocks until all are imported
+ imported := make(chan *types.Block)
+ tester.fetcher.importedHook = func(block *types.Block) { imported <- block }
+
+ for i := len(hashes) - 2; i >= 0; i-- {
+ tester.fetcher.Notify("valid", hashes[i], uint64(len(hashes)-i-1), time.Now().Add(-arriveTimeout), headerFetcher, bodyFetcher)
+ verifyImportEvent(t, imported, true)
+ }
+ verifyImportDone(t, imported)
+}
+
+// Tests that if blocks are announced by multiple peers (or even the same buggy
+// peer), they will only get downloaded at most once.
+func TestConcurrentAnnouncements62(t *testing.T) { testConcurrentAnnouncements(t, 62) }
+func TestConcurrentAnnouncements63(t *testing.T) { testConcurrentAnnouncements(t, 63) }
+func TestConcurrentAnnouncements64(t *testing.T) { testConcurrentAnnouncements(t, 64) }
+
+func testConcurrentAnnouncements(t *testing.T, protocol int) {
+ // Create a chain of blocks to import
+ targetBlocks := 4 * hashLimit
+ hashes, blocks := makeChain(targetBlocks, 0, genesis)
+
+ // Assemble a tester with a built in counter for the requests
+ tester := newTester()
+ firstHeaderFetcher := tester.makeHeaderFetcher("first", blocks, -gatherSlack)
+ firstBodyFetcher := tester.makeBodyFetcher("first", blocks, 0)
+ secondHeaderFetcher := tester.makeHeaderFetcher("second", blocks, -gatherSlack)
+ secondBodyFetcher := tester.makeBodyFetcher("second", blocks, 0)
+
+ counter := uint32(0)
+ firstHeaderWrapper := func(hash common.Hash) error {
+ atomic.AddUint32(&counter, 1)
+ return firstHeaderFetcher(hash)
+ }
+ secondHeaderWrapper := func(hash common.Hash) error {
+ atomic.AddUint32(&counter, 1)
+ return secondHeaderFetcher(hash)
+ }
+ // Iteratively announce blocks until all are imported
+ imported := make(chan *types.Block)
+ tester.fetcher.importedHook = func(block *types.Block) { imported <- block }
+
+ for i := len(hashes) - 2; i >= 0; i-- {
+ tester.fetcher.Notify("first", hashes[i], uint64(len(hashes)-i-1), time.Now().Add(-arriveTimeout), firstHeaderWrapper, firstBodyFetcher)
+ tester.fetcher.Notify("second", hashes[i], uint64(len(hashes)-i-1), time.Now().Add(-arriveTimeout+time.Millisecond), secondHeaderWrapper, secondBodyFetcher)
+ tester.fetcher.Notify("second", hashes[i], uint64(len(hashes)-i-1), time.Now().Add(-arriveTimeout-time.Millisecond), secondHeaderWrapper, secondBodyFetcher)
+ verifyImportEvent(t, imported, true)
+ }
+ verifyImportDone(t, imported)
+
+ // Make sure no blocks were retrieved twice
+ if int(counter) != targetBlocks {
+ t.Fatalf("retrieval count mismatch: have %v, want %v", counter, targetBlocks)
+ }
+}
+
+// Tests that announcements arriving while a previous is being fetched still
+// results in a valid import.
+func TestOverlappingAnnouncements62(t *testing.T) { testOverlappingAnnouncements(t, 62) }
+func TestOverlappingAnnouncements63(t *testing.T) { testOverlappingAnnouncements(t, 63) }
+func TestOverlappingAnnouncements64(t *testing.T) { testOverlappingAnnouncements(t, 64) }
+
+func testOverlappingAnnouncements(t *testing.T, protocol int) {
+ // Create a chain of blocks to import
+ targetBlocks := 4 * hashLimit
+ hashes, blocks := makeChain(targetBlocks, 0, genesis)
+
+ tester := newTester()
+ headerFetcher := tester.makeHeaderFetcher("valid", blocks, -gatherSlack)
+ bodyFetcher := tester.makeBodyFetcher("valid", blocks, 0)
+
+ // Iteratively announce blocks, but overlap them continuously
+ overlap := 16
+ imported := make(chan *types.Block, len(hashes)-1)
+ for i := 0; i < overlap; i++ {
+ imported <- nil
+ }
+ tester.fetcher.importedHook = func(block *types.Block) { imported <- block }
+
+ for i := len(hashes) - 2; i >= 0; i-- {
+ tester.fetcher.Notify("valid", hashes[i], uint64(len(hashes)-i-1), time.Now().Add(-arriveTimeout), headerFetcher, bodyFetcher)
+ select {
+ case <-imported:
+ case <-time.After(time.Second):
+ t.Fatalf("block %d: import timeout", len(hashes)-i)
+ }
+ }
+ // Wait for all the imports to complete and check count
+ verifyImportCount(t, imported, overlap)
+}
+
+// Tests that announces already being retrieved will not be duplicated.
+func TestPendingDeduplication62(t *testing.T) { testPendingDeduplication(t, 62) }
+func TestPendingDeduplication63(t *testing.T) { testPendingDeduplication(t, 63) }
+func TestPendingDeduplication64(t *testing.T) { testPendingDeduplication(t, 64) }
+
+func testPendingDeduplication(t *testing.T, protocol int) {
+ // Create a hash and corresponding block
+ hashes, blocks := makeChain(1, 0, genesis)
+
+ // Assemble a tester with a built in counter and delayed fetcher
+ tester := newTester()
+ headerFetcher := tester.makeHeaderFetcher("repeater", blocks, -gatherSlack)
+ bodyFetcher := tester.makeBodyFetcher("repeater", blocks, 0)
+
+ delay := 50 * time.Millisecond
+ counter := uint32(0)
+ headerWrapper := func(hash common.Hash) error {
+ atomic.AddUint32(&counter, 1)
+
+ // Simulate a long running fetch
+ go func() {
+ time.Sleep(delay)
+ headerFetcher(hash)
+ }()
+ return nil
+ }
+ // Announce the same block many times until it's fetched (wait for any pending ops)
+ for tester.getBlock(hashes[0]) == nil {
+ tester.fetcher.Notify("repeater", hashes[0], 1, time.Now().Add(-arriveTimeout), headerWrapper, bodyFetcher)
+ time.Sleep(time.Millisecond)
+ }
+ time.Sleep(delay)
+
+ // Check that all blocks were imported and none fetched twice
+ if imported := len(tester.blocks); imported != 2 {
+ t.Fatalf("synchronised block mismatch: have %v, want %v", imported, 2)
+ }
+ if int(counter) != 1 {
+ t.Fatalf("retrieval count mismatch: have %v, want %v", counter, 1)
+ }
+}
+
+// Tests that announcements retrieved in a random order are cached and eventually
+// imported when all the gaps are filled in.
+func TestRandomArrivalImport62(t *testing.T) { testRandomArrivalImport(t, 62) }
+func TestRandomArrivalImport63(t *testing.T) { testRandomArrivalImport(t, 63) }
+func TestRandomArrivalImport64(t *testing.T) { testRandomArrivalImport(t, 64) }
+
+func testRandomArrivalImport(t *testing.T, protocol int) {
+ // Create a chain of blocks to import, and choose one to delay
+ targetBlocks := maxQueueDist
+ hashes, blocks := makeChain(targetBlocks, 0, genesis)
+ skip := targetBlocks / 2
+
+ tester := newTester()
+ headerFetcher := tester.makeHeaderFetcher("valid", blocks, -gatherSlack)
+ bodyFetcher := tester.makeBodyFetcher("valid", blocks, 0)
+
+ // Iteratively announce blocks, skipping one entry
+ imported := make(chan *types.Block, len(hashes)-1)
+ tester.fetcher.importedHook = func(block *types.Block) { imported <- block }
+
+ for i := len(hashes) - 1; i >= 0; i-- {
+ if i != skip {
+ tester.fetcher.Notify("valid", hashes[i], uint64(len(hashes)-i-1), time.Now().Add(-arriveTimeout), headerFetcher, bodyFetcher)
+ time.Sleep(time.Millisecond)
+ }
+ }
+ // Finally announce the skipped entry and check full import
+ tester.fetcher.Notify("valid", hashes[skip], uint64(len(hashes)-skip-1), time.Now().Add(-arriveTimeout), headerFetcher, bodyFetcher)
+ verifyImportCount(t, imported, len(hashes)-1)
+}
+
+// Tests that direct block enqueues (due to block propagation vs. hash announce)
+// are correctly schedule, filling and import queue gaps.
+func TestQueueGapFill62(t *testing.T) { testQueueGapFill(t, 62) }
+func TestQueueGapFill63(t *testing.T) { testQueueGapFill(t, 63) }
+func TestQueueGapFill64(t *testing.T) { testQueueGapFill(t, 64) }
+
+func testQueueGapFill(t *testing.T, protocol int) {
+ // Create a chain of blocks to import, and choose one to not announce at all
+ targetBlocks := maxQueueDist
+ hashes, blocks := makeChain(targetBlocks, 0, genesis)
+ skip := targetBlocks / 2
+
+ tester := newTester()
+ headerFetcher := tester.makeHeaderFetcher("valid", blocks, -gatherSlack)
+ bodyFetcher := tester.makeBodyFetcher("valid", blocks, 0)
+
+ // Iteratively announce blocks, skipping one entry
+ imported := make(chan *types.Block, len(hashes)-1)
+ tester.fetcher.importedHook = func(block *types.Block) { imported <- block }
+
+ for i := len(hashes) - 1; i >= 0; i-- {
+ if i != skip {
+ tester.fetcher.Notify("valid", hashes[i], uint64(len(hashes)-i-1), time.Now().Add(-arriveTimeout), headerFetcher, bodyFetcher)
+ time.Sleep(time.Millisecond)
+ }
+ }
+ // Fill the missing block directly as if propagated
+ tester.fetcher.Enqueue("valid", blocks[hashes[skip]])
+ verifyImportCount(t, imported, len(hashes)-1)
+}
+
+// Tests that blocks arriving from various sources (multiple propagations, hash
+// announces, etc) do not get scheduled for import multiple times.
+func TestImportDeduplication62(t *testing.T) { testImportDeduplication(t, 62) }
+func TestImportDeduplication63(t *testing.T) { testImportDeduplication(t, 63) }
+func TestImportDeduplication64(t *testing.T) { testImportDeduplication(t, 64) }
+
+func testImportDeduplication(t *testing.T, protocol int) {
+ // Create two blocks to import (one for duplication, the other for stalling)
+ hashes, blocks := makeChain(2, 0, genesis)
+
+ // Create the tester and wrap the importer with a counter
+ tester := newTester()
+ headerFetcher := tester.makeHeaderFetcher("valid", blocks, -gatherSlack)
+ bodyFetcher := tester.makeBodyFetcher("valid", blocks, 0)
+
+ counter := uint32(0)
+ tester.fetcher.insertChain = func(blocks types.Blocks) (int, error) {
+ atomic.AddUint32(&counter, uint32(len(blocks)))
+ return tester.insertChain(blocks)
+ }
+ // Instrument the fetching and imported events
+ fetching := make(chan []common.Hash)
+ imported := make(chan *types.Block, len(hashes)-1)
+ tester.fetcher.fetchingHook = func(hashes []common.Hash) { fetching <- hashes }
+ tester.fetcher.importedHook = func(block *types.Block) { imported <- block }
+
+ // Announce the duplicating block, wait for retrieval, and also propagate directly
+ tester.fetcher.Notify("valid", hashes[0], 1, time.Now().Add(-arriveTimeout), headerFetcher, bodyFetcher)
+ <-fetching
+
+ tester.fetcher.Enqueue("valid", blocks[hashes[0]])
+ tester.fetcher.Enqueue("valid", blocks[hashes[0]])
+ tester.fetcher.Enqueue("valid", blocks[hashes[0]])
+
+ // Fill the missing block directly as if propagated, and check import uniqueness
+ tester.fetcher.Enqueue("valid", blocks[hashes[1]])
+ verifyImportCount(t, imported, 2)
+
+ if counter != 2 {
+ t.Fatalf("import invocation count mismatch: have %v, want %v", counter, 2)
+ }
+}
+
+// Tests that blocks with numbers much lower or higher than out current head get
+// discarded to prevent wasting resources on useless blocks from faulty peers.
+func TestDistantPropagationDiscarding(t *testing.T) {
+ // Create a long chain to import and define the discard boundaries
+ hashes, blocks := makeChain(3*maxQueueDist, 0, genesis)
+ head := hashes[len(hashes)/2]
+
+ low, high := len(hashes)/2+maxUncleDist+1, len(hashes)/2-maxQueueDist-1
+
+ // Create a tester and simulate a head block being the middle of the above chain
+ tester := newTester()
+
+ tester.lock.Lock()
+ tester.hashes = []common.Hash{head}
+ tester.blocks = map[common.Hash]*types.Block{head: blocks[head]}
+ tester.lock.Unlock()
+
+ // Ensure that a block with a lower number than the threshold is discarded
+ tester.fetcher.Enqueue("lower", blocks[hashes[low]])
+ time.Sleep(10 * time.Millisecond)
+ if !tester.fetcher.queue.Empty() {
+ t.Fatalf("fetcher queued stale block")
+ }
+ // Ensure that a block with a higher number than the threshold is discarded
+ tester.fetcher.Enqueue("higher", blocks[hashes[high]])
+ time.Sleep(10 * time.Millisecond)
+ if !tester.fetcher.queue.Empty() {
+ t.Fatalf("fetcher queued future block")
+ }
+}
+
+// Tests that announcements with numbers much lower or higher than out current
+// head get discarded to prevent wasting resources on useless blocks from faulty
+// peers.
+func TestDistantAnnouncementDiscarding62(t *testing.T) { testDistantAnnouncementDiscarding(t, 62) }
+func TestDistantAnnouncementDiscarding63(t *testing.T) { testDistantAnnouncementDiscarding(t, 63) }
+func TestDistantAnnouncementDiscarding64(t *testing.T) { testDistantAnnouncementDiscarding(t, 64) }
+
+func testDistantAnnouncementDiscarding(t *testing.T, protocol int) {
+ // Create a long chain to import and define the discard boundaries
+ hashes, blocks := makeChain(3*maxQueueDist, 0, genesis)
+ head := hashes[len(hashes)/2]
+
+ low, high := len(hashes)/2+maxUncleDist+1, len(hashes)/2-maxQueueDist-1
+
+ // Create a tester and simulate a head block being the middle of the above chain
+ tester := newTester()
+
+ tester.lock.Lock()
+ tester.hashes = []common.Hash{head}
+ tester.blocks = map[common.Hash]*types.Block{head: blocks[head]}
+ tester.lock.Unlock()
+
+ headerFetcher := tester.makeHeaderFetcher("lower", blocks, -gatherSlack)
+ bodyFetcher := tester.makeBodyFetcher("lower", blocks, 0)
+
+ fetching := make(chan struct{}, 2)
+ tester.fetcher.fetchingHook = func(hashes []common.Hash) { fetching <- struct{}{} }
+
+ // Ensure that a block with a lower number than the threshold is discarded
+ tester.fetcher.Notify("lower", hashes[low], blocks[hashes[low]].NumberU64(), time.Now().Add(-arriveTimeout), headerFetcher, bodyFetcher)
+ select {
+ case <-time.After(50 * time.Millisecond):
+ case <-fetching:
+ t.Fatalf("fetcher requested stale header")
+ }
+ // Ensure that a block with a higher number than the threshold is discarded
+ tester.fetcher.Notify("higher", hashes[high], blocks[hashes[high]].NumberU64(), time.Now().Add(-arriveTimeout), headerFetcher, bodyFetcher)
+ select {
+ case <-time.After(50 * time.Millisecond):
+ case <-fetching:
+ t.Fatalf("fetcher requested future header")
+ }
+}
+
+// Tests that peers announcing blocks with invalid numbers (i.e. not matching
+// the headers provided afterwards) get dropped as malicious.
+func TestInvalidNumberAnnouncement62(t *testing.T) { testInvalidNumberAnnouncement(t, 62) }
+func TestInvalidNumberAnnouncement63(t *testing.T) { testInvalidNumberAnnouncement(t, 63) }
+func TestInvalidNumberAnnouncement64(t *testing.T) { testInvalidNumberAnnouncement(t, 64) }
+
+func testInvalidNumberAnnouncement(t *testing.T, protocol int) {
+ // Create a single block to import and check numbers against
+ hashes, blocks := makeChain(1, 0, genesis)
+
+ tester := newTester()
+ badHeaderFetcher := tester.makeHeaderFetcher("bad", blocks, -gatherSlack)
+ badBodyFetcher := tester.makeBodyFetcher("bad", blocks, 0)
+
+ imported := make(chan *types.Block)
+ tester.fetcher.importedHook = func(block *types.Block) { imported <- block }
+
+ // Announce a block with a bad number, check for immediate drop
+ tester.fetcher.Notify("bad", hashes[0], 2, time.Now().Add(-arriveTimeout), badHeaderFetcher, badBodyFetcher)
+ verifyImportEvent(t, imported, false)
+
+ tester.lock.RLock()
+ dropped := tester.drops["bad"]
+ tester.lock.RUnlock()
+
+ if !dropped {
+ t.Fatalf("peer with invalid numbered announcement not dropped")
+ }
+
+ goodHeaderFetcher := tester.makeHeaderFetcher("good", blocks, -gatherSlack)
+ goodBodyFetcher := tester.makeBodyFetcher("good", blocks, 0)
+ // Make sure a good announcement passes without a drop
+ tester.fetcher.Notify("good", hashes[0], 1, time.Now().Add(-arriveTimeout), goodHeaderFetcher, goodBodyFetcher)
+ verifyImportEvent(t, imported, true)
+
+ tester.lock.RLock()
+ dropped = tester.drops["good"]
+ tester.lock.RUnlock()
+
+ if dropped {
+ t.Fatalf("peer with valid numbered announcement dropped")
+ }
+ verifyImportDone(t, imported)
+}
+
+// Tests that if a block is empty (i.e. header only), no body request should be
+// made, and instead the header should be assembled into a whole block in itself.
+func TestEmptyBlockShortCircuit62(t *testing.T) { testEmptyBlockShortCircuit(t, 62) }
+func TestEmptyBlockShortCircuit63(t *testing.T) { testEmptyBlockShortCircuit(t, 63) }
+func TestEmptyBlockShortCircuit64(t *testing.T) { testEmptyBlockShortCircuit(t, 64) }
+
+func testEmptyBlockShortCircuit(t *testing.T, protocol int) {
+ // Create a chain of blocks to import
+ hashes, blocks := makeChain(32, 0, genesis)
+
+ tester := newTester()
+ headerFetcher := tester.makeHeaderFetcher("valid", blocks, -gatherSlack)
+ bodyFetcher := tester.makeBodyFetcher("valid", blocks, 0)
+
+ // Add a monitoring hook for all internal events
+ fetching := make(chan []common.Hash)
+ tester.fetcher.fetchingHook = func(hashes []common.Hash) { fetching <- hashes }
+
+ completing := make(chan []common.Hash)
+ tester.fetcher.completingHook = func(hashes []common.Hash) { completing <- hashes }
+
+ imported := make(chan *types.Block)
+ tester.fetcher.importedHook = func(block *types.Block) { imported <- block }
+
+ // Iteratively announce blocks until all are imported
+ for i := len(hashes) - 2; i >= 0; i-- {
+ tester.fetcher.Notify("valid", hashes[i], uint64(len(hashes)-i-1), time.Now().Add(-arriveTimeout), headerFetcher, bodyFetcher)
+
+ // All announces should fetch the header
+ verifyFetchingEvent(t, fetching, true)
+
+ // Only blocks with data contents should request bodies
+ verifyCompletingEvent(t, completing, len(blocks[hashes[i]].Transactions()) > 0 || len(blocks[hashes[i]].Uncles()) > 0)
+
+ // Irrelevant of the construct, import should succeed
+ verifyImportEvent(t, imported, true)
+ }
+ verifyImportDone(t, imported)
+}
+
+// Tests that a peer is unable to use unbounded memory with sending infinite
+// block announcements to a node, but that even in the face of such an attack,
+// the fetcher remains operational.
+func TestHashMemoryExhaustionAttack62(t *testing.T) { testHashMemoryExhaustionAttack(t, 62) }
+func TestHashMemoryExhaustionAttack63(t *testing.T) { testHashMemoryExhaustionAttack(t, 63) }
+func TestHashMemoryExhaustionAttack64(t *testing.T) { testHashMemoryExhaustionAttack(t, 64) }
+
+func testHashMemoryExhaustionAttack(t *testing.T, protocol int) {
+ // Create a tester with instrumented import hooks
+ tester := newTester()
+
+ imported, announces := make(chan *types.Block), int32(0)
+ tester.fetcher.importedHook = func(block *types.Block) { imported <- block }
+ tester.fetcher.announceChangeHook = func(hash common.Hash, added bool) {
+ if added {
+ atomic.AddInt32(&announces, 1)
+ } else {
+ atomic.AddInt32(&announces, -1)
+ }
+ }
+ // Create a valid chain and an infinite junk chain
+ targetBlocks := hashLimit + 2*maxQueueDist
+ hashes, blocks := makeChain(targetBlocks, 0, genesis)
+ validHeaderFetcher := tester.makeHeaderFetcher("valid", blocks, -gatherSlack)
+ validBodyFetcher := tester.makeBodyFetcher("valid", blocks, 0)
+
+ attack, _ := makeChain(targetBlocks, 0, unknownBlock)
+ attackerHeaderFetcher := tester.makeHeaderFetcher("attacker", nil, -gatherSlack)
+ attackerBodyFetcher := tester.makeBodyFetcher("attacker", nil, 0)
+
+ // Feed the tester a huge hashset from the attacker, and a limited from the valid peer
+ for i := 0; i < len(attack); i++ {
+ if i < maxQueueDist {
+ tester.fetcher.Notify("valid", hashes[len(hashes)-2-i], uint64(i+1), time.Now(), validHeaderFetcher, validBodyFetcher)
+ }
+ tester.fetcher.Notify("attacker", attack[i], 1 /* don't distance drop */, time.Now(), attackerHeaderFetcher, attackerBodyFetcher)
+ }
+ if count := atomic.LoadInt32(&announces); count != hashLimit+maxQueueDist {
+ t.Fatalf("queued announce count mismatch: have %d, want %d", count, hashLimit+maxQueueDist)
+ }
+ // Wait for fetches to complete
+ verifyImportCount(t, imported, maxQueueDist)
+
+ // Feed the remaining valid hashes to ensure DOS protection state remains clean
+ for i := len(hashes) - maxQueueDist - 2; i >= 0; i-- {
+ tester.fetcher.Notify("valid", hashes[i], uint64(len(hashes)-i-1), time.Now().Add(-arriveTimeout), validHeaderFetcher, validBodyFetcher)
+ verifyImportEvent(t, imported, true)
+ }
+ verifyImportDone(t, imported)
+}
+
+// Tests that blocks sent to the fetcher (either through propagation or via hash
+// announces and retrievals) don't pile up indefinitely, exhausting available
+// system memory.
+func TestBlockMemoryExhaustionAttack(t *testing.T) {
+ // Create a tester with instrumented import hooks
+ tester := newTester()
+
+ imported, enqueued := make(chan *types.Block), int32(0)
+ tester.fetcher.importedHook = func(block *types.Block) { imported <- block }
+ tester.fetcher.queueChangeHook = func(hash common.Hash, added bool) {
+ if added {
+ atomic.AddInt32(&enqueued, 1)
+ } else {
+ atomic.AddInt32(&enqueued, -1)
+ }
+ }
+ // Create a valid chain and a batch of dangling (but in range) blocks
+ targetBlocks := hashLimit + 2*maxQueueDist
+ hashes, blocks := makeChain(targetBlocks, 0, genesis)
+ attack := make(map[common.Hash]*types.Block)
+ for i := byte(0); len(attack) < blockLimit+2*maxQueueDist; i++ {
+ hashes, blocks := makeChain(maxQueueDist-1, i, unknownBlock)
+ for _, hash := range hashes[:maxQueueDist-2] {
+ attack[hash] = blocks[hash]
+ }
+ }
+ // Try to feed all the attacker blocks make sure only a limited batch is accepted
+ for _, block := range attack {
+ tester.fetcher.Enqueue("attacker", block)
+ }
+ time.Sleep(200 * time.Millisecond)
+ if queued := atomic.LoadInt32(&enqueued); queued != blockLimit {
+ t.Fatalf("queued block count mismatch: have %d, want %d", queued, blockLimit)
+ }
+ // Queue up a batch of valid blocks, and check that a new peer is allowed to do so
+ for i := 0; i < maxQueueDist-1; i++ {
+ tester.fetcher.Enqueue("valid", blocks[hashes[len(hashes)-3-i]])
+ }
+ time.Sleep(100 * time.Millisecond)
+ if queued := atomic.LoadInt32(&enqueued); queued != blockLimit+maxQueueDist-1 {
+ t.Fatalf("queued block count mismatch: have %d, want %d", queued, blockLimit+maxQueueDist-1)
+ }
+ // Insert the missing piece (and sanity check the import)
+ tester.fetcher.Enqueue("valid", blocks[hashes[len(hashes)-2]])
+ verifyImportCount(t, imported, maxQueueDist)
+
+ // Insert the remaining blocks in chunks to ensure clean DOS protection
+ for i := maxQueueDist; i < len(hashes)-1; i++ {
+ tester.fetcher.Enqueue("valid", blocks[hashes[len(hashes)-2-i]])
+ verifyImportEvent(t, imported, true)
+ }
+ verifyImportDone(t, imported)
+}
diff --git a/dex/fetcher/metrics.go b/dex/fetcher/metrics.go
new file mode 100644
index 000000000..23b670549
--- /dev/null
+++ b/dex/fetcher/metrics.go
@@ -0,0 +1,43 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// Contains the metrics collected by the fetcher.
+
+package fetcher
+
+import (
+ "github.com/dexon-foundation/dexon/metrics"
+)
+
+var (
+ propAnnounceInMeter = metrics.NewRegisteredMeter("dex/fetcher/prop/announces/in", nil)
+ propAnnounceOutTimer = metrics.NewRegisteredTimer("dex/fetcher/prop/announces/out", nil)
+ propAnnounceDropMeter = metrics.NewRegisteredMeter("dex/fetcher/prop/announces/drop", nil)
+ propAnnounceDOSMeter = metrics.NewRegisteredMeter("dex/fetcher/prop/announces/dos", nil)
+
+ propBroadcastInMeter = metrics.NewRegisteredMeter("dex/fetcher/prop/broadcasts/in", nil)
+ propBroadcastOutTimer = metrics.NewRegisteredTimer("dex/fetcher/prop/broadcasts/out", nil)
+ propBroadcastDropMeter = metrics.NewRegisteredMeter("dex/fetcher/prop/broadcasts/drop", nil)
+ propBroadcastDOSMeter = metrics.NewRegisteredMeter("dex/fetcher/prop/broadcasts/dos", nil)
+
+ headerFetchMeter = metrics.NewRegisteredMeter("dex/fetcher/fetch/headers", nil)
+ bodyFetchMeter = metrics.NewRegisteredMeter("dex/fetcher/fetch/bodies", nil)
+
+ headerFilterInMeter = metrics.NewRegisteredMeter("dex/fetcher/filter/headers/in", nil)
+ headerFilterOutMeter = metrics.NewRegisteredMeter("dex/fetcher/filter/headers/out", nil)
+ bodyFilterInMeter = metrics.NewRegisteredMeter("dex/fetcher/filter/bodies/in", nil)
+ bodyFilterOutMeter = metrics.NewRegisteredMeter("dex/fetcher/filter/bodies/out", nil)
+)