eth, les: defer starting LES service until ETH initial sync is finished

eth/backend.go

@@ -104,6 +104,7 @@ type Config struct {
 
 type LesServer interface {
 	Start(srvr *p2p.Server)
+	Synced()
 	Stop()
 	Protocols() []p2p.Protocol
 }
@@ -145,6 +146,7 @@ type Ethereum struct {
 
 func (s *Ethereum) AddLesServer(ls LesServer) {
 	s.lesServer = ls
+	s.protocolManager.lesServer = ls
 }
 
 // New creates a new Ethereum object (including the

eth/handler.go

@@ -87,6 +87,8 @@ type ProtocolManager struct {
 	quitSync    chan struct{}
 	noMorePeers chan struct{}
 
+	lesServer LesServer
+
 	// wait group is used for graceful shutdowns during downloading
 	// and processing
 	wg sync.WaitGroup
@@ -171,7 +173,7 @@ func NewProtocolManager(config *params.ChainConfig, fastSync bool, networkId int
 		return blockchain.CurrentBlock().NumberU64()
 	}
 	inserter := func(blocks types.Blocks) (int, error) {
-		atomic.StoreUint32(&manager.synced, 1) // Mark initial sync done on any fetcher import
+		manager.setSynced() // Mark initial sync done on any fetcher import
 		return manager.insertChain(blocks)
 	}
 	manager.fetcher = fetcher.New(blockchain.GetBlockByHash, validator, manager.BroadcastBlock, heighter, inserter, manager.removePeer)

eth/sync.go

@@ -180,7 +180,7 @@ func (pm *ProtocolManager) synchronise(peer *peer) {
 	if err := pm.downloader.Synchronise(peer.id, pHead, pTd, mode); err != nil {
 		return
 	}
-	atomic.StoreUint32(&pm.synced, 1) // Mark initial sync done
+	pm.setSynced() // Mark initial sync done
 
 	// If fast sync was enabled, and we synced up, disable it
 	if atomic.LoadUint32(&pm.fastSync) == 1 {
@@ -191,3 +191,10 @@ func (pm *ProtocolManager) synchronise(peer *peer) {
 		}
 	}
 }
+
+// setSynced sets the synced flag and notifies the light server if present
+func (pm *ProtocolManager) setSynced() {
+	if atomic.SwapUint32(&pm.synced, 1) == 0 && pm.lesServer != nil {
+		pm.lesServer.Synced()
+	}
+}