diff --git a/eth/downloader/downloader.go b/eth/downloader/downloader.go
index 499b3a5854f82d0791cb811b054a24677f8713aa..88ceeb5acf535ba40ab72106f09e3c66a0980801 100644
--- a/eth/downloader/downloader.go
+++ b/eth/downloader/downloader.go
@@ -31,7 +31,6 @@ var (
)
var (
- errLowTd = errors.New("peers TD is too low")
errBusy = errors.New("busy")
errUnknownPeer = errors.New("peer is unknown or unhealthy")
errBadPeer = errors.New("action from bad peer ignored")
@@ -94,8 +93,9 @@ type Downloader struct {
dropPeer peerDropFn // Retrieved the TD of our own chain
// Status
- synchronising int32
- notified int32
+ synchroniseMock func(id string, hash common.Hash) error // Replacement for synchronise during testing
+ synchronising int32
+ notified int32
// Channels
newPeerCh chan *peer
@@ -202,7 +202,7 @@ func (d *Downloader) Synchronise(id string, head common.Hash) {
case errBusy:
glog.V(logger.Detail).Infof("Synchronisation already in progress")
- case errTimeout, errBadPeer, errEmptyHashSet, errInvalidChain, errCrossCheckFailed:
+ case errTimeout, errBadPeer, errStallingPeer, errBannedHead, errEmptyHashSet, errPeersUnavailable, errInvalidChain, errCrossCheckFailed:
glog.V(logger.Debug).Infof("Removing peer %v: %v", id, err)
d.dropPeer(id)
@@ -218,6 +218,10 @@ func (d *Downloader) Synchronise(id string, head common.Hash) {
// it will use the best peer possible and synchronize if it's TD is higher than our own. If any of the
// checks fail an error will be returned. This method is synchronous
func (d *Downloader) synchronise(id string, hash common.Hash) error {
+ // Mock out the synchonisation if testing
+ if d.synchroniseMock != nil {
+ return d.synchroniseMock(id, hash)
+ }
// Make sure only one goroutine is ever allowed past this point at once
if !atomic.CompareAndSwapInt32(&d.synchronising, 0, 1) {
return errBusy
@@ -226,7 +230,7 @@ func (d *Downloader) synchronise(id string, hash common.Hash) error {
// If the head hash is banned, terminate immediately
if d.banned.Has(hash) {
- return errInvalidChain
+ return errBannedHead
}
// Post a user notification of the sync (only once per session)
if atomic.CompareAndSwapInt32(&d.notified, 0, 1) {
diff --git a/eth/downloader/downloader_test.go b/eth/downloader/downloader_test.go
index 6269ed87cfbe97c3ba0b210434fd866a9c027ff9..c328e7d9abfd276403ab42018718b79bd86d7e89 100644
--- a/eth/downloader/downloader_test.go
+++ b/eth/downloader/downloader_test.go
@@ -2,6 +2,7 @@ package downloader
import (
"encoding/binary"
+ "fmt"
"math/big"
"testing"
"time"
@@ -69,7 +70,7 @@ func newTester() *downloadTester {
peerBlocks: make(map[string]map[common.Hash]*types.Block),
}
var mux event.TypeMux
- downloader := New(&mux, tester.hasBlock, tester.getBlock, nil)
+ downloader := New(&mux, tester.hasBlock, tester.getBlock, tester.dropPeer)
tester.downloader = downloader
return tester
@@ -130,6 +131,14 @@ func (dl *downloadTester) newPeer(id string, hashes []common.Hash, blocks map[co
return err
}
+// dropPeer simulates a hard peer removal from the connection pool.
+func (dl *downloadTester) dropPeer(id string) {
+ delete(dl.peerHashes, id)
+ delete(dl.peerBlocks, id)
+
+ dl.downloader.UnregisterPeer(id)
+}
+
// 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.
@@ -544,14 +553,14 @@ func TestBannedChainStarvationAttack(t *testing.T) {
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 {
+ if tester.downloader.banned.Has(hashes[0]) && err == errBannedHead {
+ break
+ }
t.Fatalf("synchronisation error mismatch: have %v, want %v", err, errInvalidChain)
}
// Check that the ban list grew with at least 1 new item, or all banned
bans := tester.downloader.banned.Size()
if bans < banned+1 {
- if tester.downloader.banned.Has(hashes[0]) {
- break
- }
t.Fatalf("ban count mismatch: have %v, want %v+", bans, banned+1)
}
banned = bans
@@ -606,3 +615,47 @@ func TestBannedChainMemoryExhaustionAttack(t *testing.T) {
}
}
}
+
+// Tests that misbehaving peers are disconnected, whilst behaving ones are not.
+func TestAttackerDropping(t *testing.T) {
+ // Define the disconnection requirement for individual errors
+ tests := []struct {
+ result error
+ drop bool
+ }{
+ {nil, false}, // Sync succeeded, all is well
+ {errBusy, false}, // Sync is already in progress, no problem
+ {errUnknownPeer, false}, // Peer is unknown, was already dropped, don't double drop
+ {errBadPeer, true}, // Peer was deemed bad for some reason, drop it
+ {errStallingPeer, true}, // Peer was detected to be stalling, drop it
+ {errBannedHead, true}, // Peer's head hash is a known bad hash, drop it
+ {errNoPeers, false}, // No peers to download from, soft race, no issue
+ {errPendingQueue, false}, // There are blocks still cached, wait to exhaust, no issue
+ {errTimeout, true}, // No hashes received in due time, drop the peer
+ {errEmptyHashSet, true}, // No hashes were returned as a response, drop as it's a dead end
+ {errPeersUnavailable, true}, // Nobody had the advertised blocks, drop the advertiser
+ {errInvalidChain, true}, // Hash chain was detected as invalid, definitely drop
+ {errCrossCheckFailed, true}, // Hash-origin failed to pass a block cross check, drop
+ {errCancelHashFetch, false}, // Synchronisation was canceled, origin may be innocent, don't drop
+ {errCancelBlockFetch, false}, // Synchronisation was canceled, origin may be innocent, don't drop
+ }
+ // Run the tests and check disconnection status
+ tester := newTester()
+ for i, tt := range tests {
+ // Register a new peer and ensure it's presence
+ id := fmt.Sprintf("test %d", i)
+ if err := tester.newPeer(id, []common.Hash{knownHash}, nil); err != nil {
+ t.Fatalf("test %d: failed to register new peer: %v", i, err)
+ }
+ if _, ok := tester.peerHashes[id]; !ok {
+ t.Fatalf("test %d: registered peer not found", i)
+ }
+ // Simulate a synchronisation and check the required result
+ tester.downloader.synchroniseMock = func(string, common.Hash) error { return tt.result }
+
+ tester.downloader.Synchronise(id, knownHash)
+ if _, ok := tester.peerHashes[id]; !ok != tt.drop {
+ t.Errorf("test %d: peer drop mismatch for %v: have %v, want %v", i, tt.result, !ok, tt.drop)
+ }
+ }
+}