eth/downloader: support individual peers in the test suite

eth/downloader/downloader_test.go

@@ -16,6 +16,8 @@ var (
 	knownHash   = common.Hash{1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
 	unknownHash = common.Hash{9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9}
 	bannedHash  = common.Hash{5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5}
+
+	genesis = createBlock(1, common.Hash{}, knownHash)
 )
 
 func createHashes(start, amount int) (hashes []common.Hash) {
@@ -51,26 +53,20 @@ func createBlocksFromHashes(hashes []common.Hash) map[common.Hash]*types.Block {
 type downloadTester struct {
 	downloader *Downloader
 
-	hashes []common.Hash                // Chain of hashes simulating
-	blocks map[common.Hash]*types.Block // Blocks associated with the hashes
-	chain  []common.Hash                // Block-chain being constructed
+	ownHashes  []common.Hash                           // Hash chain belonging to the tester
+	ownBlocks  map[common.Hash]*types.Block            // Blocks belonging to the tester
+	peerHashes map[string][]common.Hash                // Hash chain belonging to different test peers
+	peerBlocks map[string]map[common.Hash]*types.Block // Blocks belonging to different test peers
 
 	maxHashFetch int // Overrides the maximum number of retrieved hashes
-
-	t            *testing.T
-	done         chan bool
-	activePeerId string
 }
 
-func newTester(t *testing.T, hashes []common.Hash, blocks map[common.Hash]*types.Block) *downloadTester {
+func newTester() *downloadTester {
 	tester := &downloadTester{
-		t: t,
-
-		hashes: hashes,
-		blocks: blocks,
-		chain:  []common.Hash{knownHash},
-
-		done: make(chan bool),
+		ownHashes:  []common.Hash{knownHash},
+		ownBlocks:  map[common.Hash]*types.Block{knownHash: genesis},
+		peerHashes: make(map[string][]common.Hash),
+		peerBlocks: make(map[string]map[common.Hash]*types.Block),
 	}
 	var mux event.TypeMux
 	downloader := New(&mux, tester.hasBlock, tester.getBlock, nil)
@@ -79,13 +75,6 @@ func newTester(t *testing.T, hashes []common.Hash, blocks map[common.Hash]*types
 	return tester
 }
 
-// sync is a simple wrapper around the downloader to start synchronisation and
-// block until it returns
-func (dl *downloadTester) sync(peerId string, head common.Hash) error {
-	dl.activePeerId = peerId
-	return dl.downloader.synchronise(peerId, head)
-}
-
 // syncTake is starts synchronising with a remote peer, but concurrently it also
 // starts fetching blocks that the downloader retrieved. IT blocks until both go
 // routines terminate.
@@ -102,12 +91,17 @@ func (dl *downloadTester) syncTake(peerId string, head common.Hash) ([]*Block, e
 				time.Sleep(time.Millisecond)
 			}
 			// Take a batch of blocks and accumulate
-			took = append(took, dl.downloader.TakeBlocks()...)
+			blocks := dl.downloader.TakeBlocks()
+			for _, block := range blocks {
+				dl.ownHashes = append(dl.ownHashes, block.RawBlock.Hash())
+				dl.ownBlocks[block.RawBlock.Hash()] = block.RawBlock
+			}
+			took = append(took, blocks...)
 		}
 		done <- struct{}{}
 	}()
 	// Start the downloading, sync the taker and return
-	err := dl.sync(peerId, head)
+	err := dl.downloader.synchronise(peerId, head)
 
 	done <- struct{}{}
 	<-done
@@ -115,65 +109,76 @@ func (dl *downloadTester) syncTake(peerId string, head common.Hash) ([]*Block, e
 	return took, err
 }
 
+// hasBlock checks if a block is present in the testers canonical chain.
 func (dl *downloadTester) hasBlock(hash common.Hash) bool {
-	for _, h := range dl.chain {
-		if h == hash {
-			return true
-		}
-	}
-	return false
+	return dl.getBlock(hash) != nil
 }
 
+// getBlock retrieves a block from the testers canonical chain.
 func (dl *downloadTester) getBlock(hash common.Hash) *types.Block {
-	return dl.blocks[knownHash]
+	return dl.ownBlocks[hash]
+}
+
+// newPeer registers a new block download source into the downloader.
+func (dl *downloadTester) newPeer(id string, hashes []common.Hash, blocks map[common.Hash]*types.Block) error {
+	err := dl.downloader.RegisterPeer(id, hashes[0], dl.peerGetHashesFn(id), dl.peerGetBlocksFn(id))
+	if err == nil {
+		// Assign the owned hashes and blocks to the peer
+		dl.peerHashes[id] = hashes
+		dl.peerBlocks[id] = blocks
+	}
+	return err
 }
 
-// getHashes retrieves a batch of hashes for reconstructing the chain.
-func (dl *downloadTester) getHashes(head common.Hash) error {
-	limit := MaxHashFetch
-	if dl.maxHashFetch > 0 {
-		limit = dl.maxHashFetch
-	}
-	// Gather the next batch of hashes
-	hashes := make([]common.Hash, 0, limit)
-	for i, hash := range dl.hashes {
-		if hash == head {
-			i++
-			for len(hashes) < cap(hashes) && i < len(dl.hashes) {
-				hashes = append(hashes, dl.hashes[i])
+// peerGetBlocksFn constructs a getHashes function associated with a particular
+// peer in the download tester. The returned function can be used to retrieve
+// batches of hashes from the particularly requested peer.
+func (dl *downloadTester) peerGetHashesFn(id string) func(head common.Hash) error {
+	return func(head common.Hash) error {
+		limit := MaxHashFetch
+		if dl.maxHashFetch > 0 {
+			limit = dl.maxHashFetch
+		}
+		// Gather the next batch of hashes
+		hashes := dl.peerHashes[id]
+		result := make([]common.Hash, 0, limit)
+		for i, hash := range hashes {
+			if hash == head {
 				i++
+				for len(result) < cap(result) && i < len(hashes) {
+					result = append(result, hashes[i])
+					i++
+				}
+				break
 			}
-			break
 		}
+		// Delay delivery a bit to allow attacks to unfold
+		go func() {
+			time.Sleep(time.Millisecond)
+			dl.downloader.DeliverHashes(id, result)
+		}()
+		return nil
 	}
-	// Delay delivery a bit to allow attacks to unfold
-	id := dl.activePeerId
-	go func() {
-		time.Sleep(time.Millisecond)
-		dl.downloader.DeliverHashes(id, hashes)
-	}()
-	return nil
 }
 
-func (dl *downloadTester) getBlocks(id string) func([]common.Hash) error {
+// peerGetBlocksFn constructs a getBlocks function associated with a particular
+// peer in the download tester. The returned function can be used to retrieve
+// batches of blocks from the particularly requested peer.
+func (dl *downloadTester) peerGetBlocksFn(id string) func([]common.Hash) error {
 	return func(hashes []common.Hash) error {
-		blocks := make([]*types.Block, 0, len(hashes))
+		blocks := dl.peerBlocks[id]
+		result := make([]*types.Block, 0, len(hashes))
 		for _, hash := range hashes {
-			if block, ok := dl.blocks[hash]; ok {
-				blocks = append(blocks, block)
+			if block, ok := blocks[hash]; ok {
+				result = append(result, block)
 			}
 		}
-		go dl.downloader.DeliverBlocks(id, blocks)
+		go dl.downloader.DeliverBlocks(id, result)
 
 		return nil
 	}
 }
 
-// newPeer registers a new block download source into the syncer.
-func (dl *downloadTester) newPeer(id string, td *big.Int, hash common.Hash) error {
-	return dl.downloader.RegisterPeer(id, hash, dl.getHashes, dl.getBlocks(id))
-}
-
 // Tests that simple synchronization, without throttling from a good peer works.
 func TestSynchronisation(t *testing.T) {
 	// Create a small enough block chain to download and the tester
@@ -181,11 +186,11 @@ func TestSynchronisation(t *testing.T) {
 	hashes := createHashes(0, targetBlocks)
 	blocks := createBlocksFromHashes(hashes)
 
-	tester := newTester(t, hashes, blocks)
-	tester.newPeer("peer", big.NewInt(10000), hashes[0])
+	tester := newTester()
+	tester.newPeer("peer", hashes, blocks)
 
 	// Synchronise with the peer and make sure all blocks were retrieved
-	if err := tester.sync("peer", hashes[0]); err != nil {
+	if err := tester.downloader.synchronise("peer", hashes[0]); err != nil {
 		t.Fatalf("failed to synchronise blocks: %v", err)
 	}
 	if queued := len(tester.downloader.queue.blockPool); queued != targetBlocks {
@@ -200,11 +205,11 @@ func TestBlockTaking(t *testing.T) {
 	hashes := createHashes(0, targetBlocks)
 	blocks := createBlocksFromHashes(hashes)
 
-	tester := newTester(t, hashes, blocks)
-	tester.newPeer("peer", big.NewInt(10000), hashes[0])
+	tester := newTester()
+	tester.newPeer("peer", hashes, blocks)
 
 	// Synchronise with the peer and test block retrieval
-	if err := tester.sync("peer", hashes[0]); err != nil {
+	if err := tester.downloader.synchronise("peer", hashes[0]); err != nil {
 		t.Fatalf("failed to synchronise blocks: %v", err)
 	}
 	if took := tester.downloader.TakeBlocks(); len(took) != targetBlocks {
@@ -214,7 +219,7 @@ func TestBlockTaking(t *testing.T) {
 
 // Tests that an inactive downloader will not accept incoming hashes and blocks.
 func TestInactiveDownloader(t *testing.T) {
-	tester := newTester(t, nil, nil)
+	tester := newTester()
 
 	// Check that neither hashes nor blocks are accepted
 	if err := tester.downloader.DeliverHashes("bad peer", []common.Hash{}); err != errNoSyncActive {
@@ -232,11 +237,11 @@ func TestCancel(t *testing.T) {
 	hashes := createHashes(0, targetBlocks)
 	blocks := createBlocksFromHashes(hashes)
 
-	tester := newTester(t, hashes, blocks)
-	tester.newPeer("peer", big.NewInt(10000), hashes[0])
+	tester := newTester()
+	tester.newPeer("peer", hashes, blocks)
 
 	// Synchronise with the peer, but cancel afterwards
-	if err := tester.sync("peer", hashes[0]); err != nil {
+	if err := tester.downloader.synchronise("peer", hashes[0]); err != nil {
 		t.Fatalf("failed to synchronise blocks: %v", err)
 	}
 	if !tester.downloader.Cancel() {
@@ -260,13 +265,13 @@ func TestThrottling(t *testing.T) {
 	hashes := createHashes(0, targetBlocks)
 	blocks := createBlocksFromHashes(hashes)
 
-	tester := newTester(t, hashes, blocks)
-	tester.newPeer("peer", big.NewInt(10000), hashes[0])
+	tester := newTester()
+	tester.newPeer("peer", hashes, blocks)
 
 	// Start a synchronisation concurrently
 	errc := make(chan error)
 	go func() {
-		errc <- tester.sync("peer", hashes[0])
+		errc <- tester.downloader.synchronise("peer", hashes[0])
 	}()
 	// Iteratively take some blocks, always checking the retrieval count
 	for total := 0; total < targetBlocks; {
@@ -303,9 +308,9 @@ func TestNonExistingParentAttack(t *testing.T) {
 	forged.ParentHeaderHash = unknownHash
 
 	// Try and sync with the malicious node and check that it fails
-	tester := newTester(t, hashes, blocks)
-	tester.newPeer("attack", big.NewInt(10000), hashes[0])
-	if err := tester.sync("attack", hashes[0]); err != nil {
+	tester := newTester()
+	tester.newPeer("attack", hashes, blocks)
+	if err := tester.downloader.synchronise("attack", hashes[0]); err != nil {
 		t.Fatalf("failed to synchronise blocks: %v", err)
 	}
 	bs := tester.downloader.TakeBlocks()
@@ -319,8 +324,8 @@ func TestNonExistingParentAttack(t *testing.T) {
 
 	// Reconstruct a valid chain, and try to synchronize with it
 	forged.ParentHeaderHash = knownHash
-	tester.newPeer("valid", big.NewInt(20000), hashes[0])
-	if err := tester.sync("valid", hashes[0]); err != nil {
+	tester.newPeer("valid", hashes, blocks)
+	if err := tester.downloader.synchronise("valid", hashes[0]); err != nil {
 		t.Fatalf("failed to synchronise blocks: %v", err)
 	}
 	bs = tester.downloader.TakeBlocks()
@@ -341,12 +346,12 @@ func TestRepeatingHashAttack(t *testing.T) {
 	forged := hashes[:len(hashes)-1]
 
 	// Try and sync with the malicious node
-	tester := newTester(t, forged, blocks)
-	tester.newPeer("attack", big.NewInt(10000), forged[0])
+	tester := newTester()
+	tester.newPeer("attack", forged, blocks)
 
 	errc := make(chan error)
 	go func() {
-		errc <- tester.sync("attack", hashes[0])
+		errc <- tester.downloader.synchronise("attack", hashes[0])
 	}()
 
 	// Make sure that syncing returns and does so with a failure
@@ -359,9 +364,8 @@ func TestRepeatingHashAttack(t *testing.T) {
 		}
 	}
 	// Ensure that a valid chain can still pass sync
-	tester.hashes = hashes
-	tester.newPeer("valid", big.NewInt(20000), hashes[0])
-	if err := tester.sync("valid", hashes[0]); err != nil {
+	tester.newPeer("valid", hashes, blocks)
+	if err := tester.downloader.synchronise("valid", hashes[0]); err != nil {
 		t.Fatalf("failed to synchronise blocks: %v", err)
 	}
 }
@@ -377,15 +381,15 @@ func TestNonExistingBlockAttack(t *testing.T) {
 	hashes[len(hashes)/2] = unknownHash
 
 	// Try and sync with the malicious node and check that it fails
-	tester := newTester(t, hashes, blocks)
-	tester.newPeer("attack", big.NewInt(10000), hashes[0])
-	if err := tester.sync("attack", hashes[0]); err != errPeersUnavailable {
+	tester := newTester()
+	tester.newPeer("attack", hashes, blocks)
+	if err := tester.downloader.synchronise("attack", hashes[0]); err != errPeersUnavailable {
 		t.Fatalf("synchronisation error mismatch: have %v, want %v", err, errPeersUnavailable)
 	}
 	// Ensure that a valid chain can still pass sync
 	hashes[len(hashes)/2] = origin
-	tester.newPeer("valid", big.NewInt(20000), hashes[0])
-	if err := tester.sync("valid", hashes[0]); err != nil {
+	tester.newPeer("valid", hashes, blocks)
+	if err := tester.downloader.synchronise("valid", hashes[0]); err != nil {
 		t.Fatalf("failed to synchronise blocks: %v", err)
 	}
 }
@@ -408,14 +412,13 @@ func TestInvalidHashOrderAttack(t *testing.T) {
 	copy(reverse[blockCacheLimit:], chunk2)
 
 	// Try and sync with the malicious node and check that it fails
-	tester := newTester(t, reverse, blocks)
-	tester.newPeer("attack", big.NewInt(10000), reverse[0])
+	tester := newTester()
+	tester.newPeer("attack", reverse, blocks)
 	if _, err := tester.syncTake("attack", reverse[0]); err != errInvalidChain {
 		t.Fatalf("synchronisation error mismatch: have %v, want %v", err, errInvalidChain)
 	}
 	// Ensure that a valid chain can still pass sync
-	tester.hashes = hashes
-	tester.newPeer("valid", big.NewInt(20000), hashes[0])
+	tester.newPeer("valid", hashes, blocks)
 	if _, err := tester.syncTake("valid", hashes[0]); err != nil {
 		t.Fatalf("failed to synchronise blocks: %v", err)
 	}
@@ -431,8 +434,8 @@ func TestMadeupHashChainAttack(t *testing.T) {
 	hashes := createHashes(0, 1024*blockCacheLimit)
 
 	// Try and sync with the malicious node and check that it fails
-	tester := newTester(t, hashes, nil)
-	tester.newPeer("attack", big.NewInt(10000), hashes[0])
+	tester := newTester()
+	tester.newPeer("attack", hashes, nil)
 	if _, err := tester.syncTake("attack", hashes[0]); err != errCrossCheckFailed {
 		t.Fatalf("synchronisation error mismatch: have %v, want %v", err, errCrossCheckFailed)
 	}
@@ -445,11 +448,11 @@ func TestMadeupHashChainAttack(t *testing.T) {
 func TestMadeupHashChainDrippingAttack(t *testing.T) {
 	// Create a random chain of hashes to drip
 	hashes := createHashes(0, 16*blockCacheLimit)
-	tester := newTester(t, hashes, nil)
+	tester := newTester()
 
 	// Try and sync with the attacker, one hash at a time
 	tester.maxHashFetch = 1
-	tester.newPeer("attack", big.NewInt(10000), hashes[0])
+	tester.newPeer("attack", hashes, nil)
 	if _, err := tester.syncTake("attack", hashes[0]); err != errStallingPeer {
 		t.Fatalf("synchronisation error mismatch: have %v, want %v", err, errStallingPeer)
 	}
@@ -473,8 +476,8 @@ func TestMadeupBlockChainAttack(t *testing.T) {
 		gapped[i] = hashes[2*i]
 	}
 	// Try and sync with the malicious node and check that it fails
-	tester := newTester(t, gapped, blocks)
-	tester.newPeer("attack", big.NewInt(10000), gapped[0])
+	tester := newTester()
+	tester.newPeer("attack", gapped, blocks)
 	if _, err := tester.syncTake("attack", gapped[0]); err != errCrossCheckFailed {
 		t.Fatalf("synchronisation error mismatch: have %v, want %v", err, errCrossCheckFailed)
 	}
@@ -482,8 +485,7 @@ func TestMadeupBlockChainAttack(t *testing.T) {
 	blockSoftTTL = defaultBlockTTL
 	crossCheckCycle = defaultCrossCheckCycle
 
-	tester.hashes = hashes
-	tester.newPeer("valid", big.NewInt(20000), hashes[0])
+	tester.newPeer("valid", hashes, blocks)
 	if _, err := tester.syncTake("valid", hashes[0]); err != nil {
 		t.Fatalf("failed to synchronise blocks: %v", err)
 	}
@@ -507,8 +509,8 @@ func TestMadeupParentBlockChainAttack(t *testing.T) {
 		block.ParentHeaderHash = hash // Simulate pointing to already known hash
 	}
 	// Try and sync with the malicious node and check that it fails
-	tester := newTester(t, hashes, forges)
-	tester.newPeer("attack", big.NewInt(10000), hashes[0])
+	tester := newTester()
+	tester.newPeer("attack", hashes, forges)
 	if _, err := tester.syncTake("attack", hashes[0]); err != errCrossCheckFailed {
 		t.Fatalf("synchronisation error mismatch: have %v, want %v", err, errCrossCheckFailed)
 	}
@@ -516,8 +518,7 @@ func TestMadeupParentBlockChainAttack(t *testing.T) {
 	blockSoftTTL = defaultBlockTTL
 	crossCheckCycle = defaultCrossCheckCycle
 
-	tester.blocks = blocks
-	tester.newPeer("valid", big.NewInt(20000), hashes[0])
+	tester.newPeer("valid", hashes, blocks)
 	if _, err := tester.syncTake("valid", hashes[0]); err != nil {
 		t.Fatalf("failed to synchronise blocks: %v", err)
 	}
@@ -534,12 +535,12 @@ func TestBannedChainStarvationAttack(t *testing.T) {
 	blocks := createBlocksFromHashes(hashes)
 
 	// Create the tester and ban the selected hash
-	tester := newTester(t, hashes, blocks)
+	tester := newTester()
 	tester.downloader.banned.Add(bannedHash)
 
 	// Iteratively try to sync, and verify that the banned hash list grows until
 	// the head of the invalid chain is blocked too.
-	tester.newPeer("attack", big.NewInt(10000), hashes[0])
+	tester.newPeer("attack", hashes, blocks)
 	for banned := tester.downloader.banned.Size(); ; {
 		// Try to sync with the attacker, check hash chain failure
 		if _, err := tester.syncTake("attack", hashes[0]); err != errInvalidChain {
@@ -556,7 +557,7 @@ func TestBannedChainStarvationAttack(t *testing.T) {
 		banned = bans
 	}
 	// Check that after banning an entire chain, bad peers get dropped
-	if err := tester.newPeer("new attacker", big.NewInt(10000), hashes[0]); err != errBannedHead {
+	if err := tester.newPeer("new attacker", hashes, blocks); err != errBannedHead {
 		t.Fatalf("peer registration mismatch: have %v, want %v", err, errBannedHead)
 	}
 	if peer := tester.downloader.peers.Peer("net attacker"); peer != nil {
@@ -579,12 +580,12 @@ func TestBannedChainMemoryExhaustionAttack(t *testing.T) {
 	blocks := createBlocksFromHashes(hashes)
 
 	// Create the tester and ban the selected hash
-	tester := newTester(t, hashes, blocks)
+	tester := newTester()
 	tester.downloader.banned.Add(bannedHash)
 
 	// Iteratively try to sync, and verify that the banned hash list grows until
 	// the head of the invalid chain is blocked too.
-	tester.newPeer("attack", big.NewInt(10000), hashes[0])
+	tester.newPeer("attack", hashes, blocks)
 	for {
 		// Try to sync with the attacker, check hash chain failure
 		if _, err := tester.syncTake("attack", hashes[0]); err != errInvalidChain {