5 files changed, 72 insertions, 9 deletions

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 91d3d96805d0..b12dae2b0b2d 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1029,6 +1029,11 @@ skip:
 	}
 }
 
+static inline bool inetdev_valid_mtu(unsigned mtu)
+{
+	return mtu >= 68;
+}
+
 /* Called only under RTNL semaphore */
 
 static int inetdev_event(struct notifier_block *this, unsigned long event,
@@ -1048,6 +1053,10 @@ static int inetdev_event(struct notifier_block *this, unsigned long event,
 				IN_DEV_CONF_SET(in_dev, NOXFRM, 1);
 				IN_DEV_CONF_SET(in_dev, NOPOLICY, 1);
 			}
+		} else if (event == NETDEV_CHANGEMTU) {
+			/* Re-enabling IP */
+			if (inetdev_valid_mtu(dev->mtu))
+				in_dev = inetdev_init(dev);
 		}
 		goto out;
 	}
@@ -1058,7 +1067,7 @@ static int inetdev_event(struct notifier_block *this, unsigned long event,
 		dev->ip_ptr = NULL;
 		break;
 	case NETDEV_UP:
-		if (dev->mtu < 68)
+		if (!inetdev_valid_mtu(dev->mtu))
 			break;
 		if (dev->flags & IFF_LOOPBACK) {
 			struct in_ifaddr *ifa;
@@ -1080,9 +1089,9 @@ static int inetdev_event(struct notifier_block *this, unsigned long event,
 		ip_mc_down(in_dev);
 		break;
 	case NETDEV_CHANGEMTU:
-		if (dev->mtu >= 68)
+		if (inetdev_valid_mtu(dev->mtu))
 			break;
-		/* MTU falled under 68, disable IP */
+		/* disable IP when MTU is not enough */
 	case NETDEV_UNREGISTER:
 		inetdev_destroy(in_dev);
 		break;
diff --git a/net/ipv4/inet_timewait_sock.c b/net/ipv4/inet_timewait_sock.c
index d985bd613d25..743f011b9a84 100644
--- a/net/ipv4/inet_timewait_sock.c
+++ b/net/ipv4/inet_timewait_sock.c
@@ -409,3 +409,38 @@ out:
 }
 
 EXPORT_SYMBOL_GPL(inet_twdr_twcal_tick);
+
+void inet_twsk_purge(struct net *net, struct inet_hashinfo *hashinfo,
+		     struct inet_timewait_death_row *twdr, int family)
+{
+	struct inet_timewait_sock *tw;
+	struct sock *sk;
+	struct hlist_node *node;
+	int h;
+
+	local_bh_disable();
+	for (h = 0; h < (hashinfo->ehash_size); h++) {
+		struct inet_ehash_bucket *head =
+			inet_ehash_bucket(hashinfo, h);
+		rwlock_t *lock = inet_ehash_lockp(hashinfo, h);
+restart:
+		write_lock(lock);
+		sk_for_each(sk, node, &head->twchain) {
+
+			tw = inet_twsk(sk);
+			if (!net_eq(twsk_net(tw), net) ||
+			    tw->tw_family != family)
+				continue;
+
+			atomic_inc(&tw->tw_refcnt);
+			write_unlock(lock);
+			inet_twsk_deschedule(tw, twdr);
+			inet_twsk_put(tw);
+
+			goto restart;
+		}
+		write_unlock(lock);
+	}
+	local_bh_enable();
+}
+EXPORT_SYMBOL_GPL(inet_twsk_purge);
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index cca921ea8550..6ee5354c9aa1 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -3116,14 +3116,23 @@ static ctl_table ipv4_route_table[] = {
 	{ .ctl_name = 0 }
 };
 
-static __net_initdata struct ctl_path ipv4_route_path[] = {
+static struct ctl_table empty[1];
+
+static struct ctl_table ipv4_skeleton[] =
+{
+	{ .procname = "route", .ctl_name = NET_IPV4_ROUTE,
+	  .mode = 0555, .child = ipv4_route_table},
+	{ .procname = "neigh", .ctl_name = NET_IPV4_NEIGH,
+	  .mode = 0555, .child = empty},
+	{ }
+};
+
+static __net_initdata struct ctl_path ipv4_path[] = {
 	{ .procname = "net", .ctl_name = CTL_NET, },
 	{ .procname = "ipv4", .ctl_name = NET_IPV4, },
-	{ .procname = "route", .ctl_name = NET_IPV4_ROUTE, },
 	{ },
 };
 
-
 static struct ctl_table ipv4_route_flush_table[] = {
 	{
 		.ctl_name 	= NET_IPV4_ROUTE_FLUSH,
@@ -3136,6 +3145,13 @@ static struct ctl_table ipv4_route_flush_table[] = {
 	{ .ctl_name = 0 },
 };
 
+static __net_initdata struct ctl_path ipv4_route_path[] = {
+	{ .procname = "net", .ctl_name = CTL_NET, },
+	{ .procname = "ipv4", .ctl_name = NET_IPV4, },
+	{ .procname = "route", .ctl_name = NET_IPV4_ROUTE, },
+	{ },
+};
+
 static __net_init int sysctl_route_net_init(struct net *net)
 {
 	struct ctl_table *tbl;
@@ -3287,7 +3303,7 @@ int __init ip_rt_init(void)
  */
 void __init ip_static_sysctl_init(void)
 {
-	register_sysctl_paths(ipv4_route_path, ipv4_route_table);
+	register_sysctl_paths(ipv4_path, ipv4_skeleton);
 }
 #endif
 
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 44c1e934824b..1b4fee20fc93 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -2376,6 +2376,7 @@ static int __net_init tcp_sk_init(struct net *net)
 static void __net_exit tcp_sk_exit(struct net *net)
 {
 	inet_ctl_sock_destroy(net->ipv4.tcp_sock);
+	inet_twsk_purge(net, &tcp_hashinfo, &tcp_death_row, AF_INET);
 }
 
 static struct pernet_operations __net_initdata tcp_sk_ops = {
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index a00532de2a8c..8165f5aa8c71 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -468,7 +468,8 @@ static unsigned tcp_syn_options(struct sock *sk, struct sk_buff *skb,
 	}
 	if (likely(sysctl_tcp_window_scaling)) {
 		opts->ws = tp->rx_opt.rcv_wscale;
-		size += TCPOLEN_WSCALE_ALIGNED;
+		if(likely(opts->ws))
+			size += TCPOLEN_WSCALE_ALIGNED;
 	}
 	if (likely(sysctl_tcp_sack)) {
 		opts->options |= OPTION_SACK_ADVERTISE;
@@ -509,7 +510,8 @@ static unsigned tcp_synack_options(struct sock *sk,
 
 	if (likely(ireq->wscale_ok)) {
 		opts->ws = ireq->rcv_wscale;
-		size += TCPOLEN_WSCALE_ALIGNED;
+		if(likely(opts->ws))
+			size += TCPOLEN_WSCALE_ALIGNED;
 	}
 	if (likely(doing_ts)) {
 		opts->options |= OPTION_TS;