From a390ca5f30e871715f28937a02e87fff050b0c75 Mon Sep 17 00:00:00 2001
From: Zsolt Felfoldi <zsfelfoldi@gmail.com>
Date: Thu, 26 Jan 2017 02:52:59 +0100
Subject: [PATCH] les, cmd/util: disable topic discovery with --nodiscover

---
 cmd/utils/flags.go |  8 ++++++--
 les/serverpool.go  | 12 +++++++++---
 2 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/cmd/utils/flags.go b/cmd/utils/flags.go
index 4b76b8334..9ba33df80 100644
--- a/cmd/utils/flags.go
+++ b/cmd/utils/flags.go
@@ -654,6 +654,10 @@ func MakeNode(ctx *cli.Context, name, gitCommit string) *node.Node {
 		vsn += "-" + gitCommit[:8]
 	}
 
+	// if we're running a light client or server, force enable the v5 peer discovery unless it is explicitly disabled with --nodiscover
+	// note that explicitly specifying --v5disc overrides --nodiscover, in which case the later only disables v4 discovery
+	forceV5Discovery := (ctx.GlobalBool(LightModeFlag.Name) || ctx.GlobalInt(LightServFlag.Name) > 0) && !ctx.GlobalBool(NoDiscoverFlag.Name)
+
 	config := &node.Config{
 		DataDir:           MakeDataDir(ctx),
 		KeyStoreDir:       ctx.GlobalString(KeyStoreDirFlag.Name),
@@ -662,8 +666,8 @@ func MakeNode(ctx *cli.Context, name, gitCommit string) *node.Node {
 		Name:              name,
 		Version:           vsn,
 		UserIdent:         makeNodeUserIdent(ctx),
-		NoDiscovery:       ctx.GlobalBool(NoDiscoverFlag.Name) || ctx.GlobalBool(LightModeFlag.Name),
-		DiscoveryV5:       ctx.GlobalBool(DiscoveryV5Flag.Name) || ctx.GlobalBool(LightModeFlag.Name) || ctx.GlobalInt(LightServFlag.Name) > 0,
+		NoDiscovery:       ctx.GlobalBool(NoDiscoverFlag.Name) || ctx.GlobalBool(LightModeFlag.Name), // always disable v4 discovery in light client mode
+		DiscoveryV5:       ctx.GlobalBool(DiscoveryV5Flag.Name) || forceV5Discovery,
 		DiscoveryV5Addr:   MakeDiscoveryV5Address(ctx),
 		BootstrapNodes:    MakeBootstrapNodes(ctx),
 		BootstrapNodesV5:  MakeBootstrapNodesV5(ctx),
diff --git a/les/serverpool.go b/les/serverpool.go
index 68e962c97..9735a718e 100644
--- a/les/serverpool.go
+++ b/les/serverpool.go
@@ -348,7 +348,9 @@ func (pool *serverPool) selectPeerWait(reqID uint64, canSend func(*peer) (bool,
 func (pool *serverPool) eventLoop() {
 	lookupCnt := 0
 	var convTime mclock.AbsTime
-	pool.discSetPeriod <- time.Millisecond * 100
+	if pool.discSetPeriod != nil {
+		pool.discSetPeriod <- time.Millisecond * 100
+	}
 	for {
 		select {
 		case entry := <-pool.timeout:
@@ -393,12 +395,16 @@ func (pool *serverPool) eventLoop() {
 				lookupCnt++
 				if pool.fastDiscover && (lookupCnt == 50 || time.Duration(mclock.Now()-convTime) > time.Minute) {
 					pool.fastDiscover = false
-					pool.discSetPeriod <- time.Minute
+					if pool.discSetPeriod != nil {
+						pool.discSetPeriod <- time.Minute
+					}
 				}
 			}
 
 		case <-pool.quit:
-			close(pool.discSetPeriod)
+			if pool.discSetPeriod != nil {
+				close(pool.discSetPeriod)
+			}
 			pool.connWg.Wait()
 			pool.saveNodes()
 			pool.wg.Done()