From 497a7f1717a798e59c9550fbb58504b08fe13b21 Mon Sep 17 00:00:00 2001 From: Péter Szilágyi Date: Tue, 16 Jun 2015 23:18:01 +0300 Subject: eth, eth/fetcher: define and enforce propagation boundaries --- eth/fetcher/fetcher.go | 55 ++++++++++++++++++++++++++------------------- eth/fetcher/fetcher_test.go | 28 +++++++++++++++++++++++ 2 files changed, 60 insertions(+), 23 deletions(-) (limited to 'eth/fetcher') diff --git a/eth/fetcher/fetcher.go b/eth/fetcher/fetcher.go index 207bd9323..76d3798cb 100644 --- a/eth/fetcher/fetcher.go +++ b/eth/fetcher/fetcher.go @@ -3,6 +3,7 @@ package fetcher import ( "errors" + "math" "math/rand" "time" @@ -60,6 +61,10 @@ type Fetcher struct { filter chan chan []*types.Block quit chan struct{} + // Block cache + queue *prque.Prque // Queue containing the import operations (block number sorted) + queued map[common.Hash]struct{} // Presence set of already queued blocks (to dedup imports) + // Callbacks hasBlock hashCheckFn // Checks if a block is present in the chain importBlock blockImporterFn // Injects a block from an origin peer into the chain @@ -73,6 +78,8 @@ func New(hasBlock hashCheckFn, importBlock blockImporterFn, chainHeight chainHei insert: make(chan *inject), filter: make(chan chan []*types.Block), quit: make(chan struct{}), + queue: prque.New(), + queued: make(map[common.Hash]struct{}), hasBlock: hasBlock, importBlock: importBlock, chainHeight: chainHeight, @@ -154,23 +161,6 @@ func (f *Fetcher) loop() { announced := make(map[common.Hash][]*announce) fetching := make(map[common.Hash]*announce) - // Create the priority queue and a matching presence set - queue := prque.New() - queued := make(map[common.Hash]struct{}) - enqueue := func(peer string, block *types.Block) { - // Make sure the block isn't in some weird place - if f.chainHeight()+maxQueueDist < block.NumberU64() { - return - } - // If not, schedule the block for future import - hash := block.Hash() - if _, ok := queued[hash]; !ok { - queued[hash] = struct{}{} - queue.Push(&inject{origin: peer, block: block}, -float32(block.NumberU64())) - - glog.V(logger.Detail).Infof("Peer %s: queued block %x, total %v", peer, hash.Bytes()[:4], queue.Size()) - } - } // Iterate the block fetching until a quit is requested fetch := time.NewTimer(0) done := make(chan common.Hash) @@ -185,16 +175,16 @@ func (f *Fetcher) loop() { } // Import any queued blocks that could potentially fit height := f.chainHeight() - for !queue.Empty() { + for !f.queue.Empty() { // If too high up the chain, continue later - op := queue.PopItem().(*inject) + op := f.queue.PopItem().(*inject) if number := op.block.NumberU64(); number > height+1 { - queue.Push(op, -float32(op.block.NumberU64())) + f.queue.Push(op, -float32(op.block.NumberU64())) break } // Otherwise if not known yet, try and import hash := op.block.Hash() - delete(queued, hash) + delete(f.queued, hash) if f.hasBlock(hash) { continue } @@ -229,7 +219,7 @@ func (f *Fetcher) loop() { case op := <-f.insert: // A direct block insertion was requested, try and fill any pending gaps - enqueue(op.origin, op.block) + f.enqueue(op.origin, op.block) case hash := <-done: // A pending import finished, remove all traces of the notification @@ -301,9 +291,28 @@ func (f *Fetcher) loop() { // Schedule the retrieved blocks for ordered import for _, block := range explicit { if announce := fetching[block.Hash()]; announce != nil { - enqueue(announce.origin, block) + f.enqueue(announce.origin, block) } } } } } + +// 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) { + // Make sure the block isn't in some weird place + if math.Abs(float64(f.chainHeight())-float64(block.NumberU64())) > maxQueueDist { + return + } + // Schedule the block for future importing + hash := block.Hash() + if _, ok := f.queued[hash]; !ok { + f.queued[hash] = struct{}{} + f.queue.Push(&inject{origin: peer, block: block}, -float32(block.NumberU64())) + + if glog.V(logger.Detail) { + glog.Infof("Peer %s: queued block %x, total %v", peer, hash.Bytes()[:4], f.queue.Size()) + } + } +} diff --git a/eth/fetcher/fetcher_test.go b/eth/fetcher/fetcher_test.go index e11a211a1..af2652a86 100644 --- a/eth/fetcher/fetcher_test.go +++ b/eth/fetcher/fetcher_test.go @@ -335,3 +335,31 @@ func TestImportDeduplication(t *testing.T) { 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 no prevent wasting resources on useless blocks from faulty peers. +func TestDistantDiscarding(t *testing.T) { + // Create a long chain to import + hashes := createHashes(3*maxQueueDist, knownHash) + blocks := createBlocksFromHashes(hashes) + + head := hashes[len(hashes)/2] + + // Create a tester and simulate a head block being the middle of the above chain + tester := newTester() + tester.ownHashes = []common.Hash{head} + tester.ownBlocks = map[common.Hash]*types.Block{head: blocks[head]} + + // Ensure that a block with a lower number than the threshold is discarded + tester.fetcher.Enqueue("lower", blocks[hashes[0]]) + 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[len(hashes)-1]]) + time.Sleep(10 * time.Millisecond) + if !tester.fetcher.queue.Empty() { + t.Fatalf("fetcher queued future block") + } +} -- cgit