[release/1.4.6] eth: don't accept transactions until we sync up with the network

(cherry picked from commit 32559cc)

Author: karalabe

eth/handler.go

@@ -59,7 +59,9 @@ type blockFetcherFn func([]common.Hash) error
 type ProtocolManager struct {
 	networkId int
 
-	fastSync   uint32
+	fastSync uint32 // Flag whether fast sync is enabled (gets disabled if we already have blocks)
+	synced   uint32 // Flag whether we're considered synchronised (enables transaction processing)
+
 	txpool     txPool
 	blockchain *core.BlockChain
 	chaindb    ethdb.Database
@@ -161,7 +163,11 @@ func NewProtocolManager(config *core.ChainConfig, fastSync bool, networkId int,
 	heighter := func() uint64 {
 		return blockchain.CurrentBlock().NumberU64()
 	}
-	manager.fetcher = fetcher.New(blockchain.GetBlock, validator, manager.BroadcastBlock, heighter, manager.insertChain, manager.removePeer)
+	inserter := func(blocks types.Blocks) (int, error) {
+		atomic.StoreUint32(&manager.synced, 1) // Mark initial sync done on any fetcher import
+		return manager.insertChain(blocks)
+	}
+	manager.fetcher = fetcher.New(blockchain.GetBlock, validator, manager.BroadcastBlock, heighter, inserter, manager.removePeer)
 
 	if blockchain.Genesis().Hash().Hex() == defaultGenesisHash && networkId == 1 {
 		glog.V(logger.Debug).Infoln("Bad Block Reporting is enabled")
@@ -698,8 +704,8 @@ func (pm *ProtocolManager) handleMsg(p *peer) error {
 		}
 
 	case msg.Code == TxMsg:
-		// Transactions arrived, make sure we have a valid chain to handle them
-		if atomic.LoadUint32(&pm.fastSync) == 1 {
+		// Transactions arrived, make sure we have a valid and fresh chain to handle them
+		if atomic.LoadUint32(&pm.synced) == 0 {
 			break
 		}
 		// Transactions can be processed, parse all of them and deliver to the pool

eth/protocol_test.go

@@ -97,6 +97,7 @@ func TestRecvTransactions63(t *testing.T) { testRecvTransactions(t, 63) }
 func testRecvTransactions(t *testing.T, protocol int) {
 	txAdded := make(chan []*types.Transaction)
 	pm := newTestProtocolManagerMust(t, false, 0, nil, txAdded)
+	pm.synced = 1 // mark synced to accept transactions
 	p, _ := newTestPeer("peer", protocol, pm, true)
 	defer pm.Stop()
 	defer p.close()

eth/sync.go

@@ -174,6 +174,8 @@ func (pm *ProtocolManager) synchronise(peer *peer) {
 	if err := pm.downloader.Synchronise(peer.id, peer.Head(), peer.Td(), mode); err != nil {
 		return
 	}
+	atomic.StoreUint32(&pm.synced, 1) // Mark initial sync done
+
 	// If fast sync was enabled, and we synced up, disable it
 	if atomic.LoadUint32(&pm.fastSync) == 1 {
 		// Disable fast sync if we indeed have something in our chain