1 files changed, 70 insertions, 6 deletions

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 16fc6f454a31..cca921ea8550 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -2914,6 +2914,68 @@ static int ipv4_sysctl_rtcache_flush_strategy(ctl_table *table,
 	return 0;
 }
 
+static void rt_secret_reschedule(int old)
+{
+	struct net *net;
+	int new = ip_rt_secret_interval;
+	int diff = new - old;
+
+	if (!diff)
+		return;
+
+	rtnl_lock();
+	for_each_net(net) {
+		int deleted = del_timer_sync(&net->ipv4.rt_secret_timer);
+
+		if (!new)
+			continue;
+
+		if (deleted) {
+			long time = net->ipv4.rt_secret_timer.expires - jiffies;
+
+			if (time <= 0 || (time += diff) <= 0)
+				time = 0;
+
+			net->ipv4.rt_secret_timer.expires = time;
+		} else
+			net->ipv4.rt_secret_timer.expires = new;
+
+		net->ipv4.rt_secret_timer.expires += jiffies;
+		add_timer(&net->ipv4.rt_secret_timer);
+	}
+	rtnl_unlock();
+}
+
+static int ipv4_sysctl_rt_secret_interval(ctl_table *ctl, int write,
+					  struct file *filp,
+					  void __user *buffer, size_t *lenp,
+					  loff_t *ppos)
+{
+	int old = ip_rt_secret_interval;
+	int ret = proc_dointvec_jiffies(ctl, write, filp, buffer, lenp, ppos);
+
+	rt_secret_reschedule(old);
+
+	return ret;
+}
+
+static int ipv4_sysctl_rt_secret_interval_strategy(ctl_table *table,
+						   int __user *name,
+						   int nlen,
+						   void __user *oldval,
+						   size_t __user *oldlenp,
+						   void __user *newval,
+						   size_t newlen)
+{
+	int old = ip_rt_secret_interval;
+	int ret = sysctl_jiffies(table, name, nlen, oldval, oldlenp, newval,
+				 newlen);
+
+	rt_secret_reschedule(old);
+
+	return ret;
+}
+
 static ctl_table ipv4_route_table[] = {
 	{
 		.ctl_name	= NET_IPV4_ROUTE_GC_THRESH,
@@ -3048,8 +3110,8 @@ static ctl_table ipv4_route_table[] = {
 		.data		= &ip_rt_secret_interval,
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
-		.proc_handler	= &proc_dointvec_jiffies,
-		.strategy	= &sysctl_jiffies,
+		.proc_handler	= &ipv4_sysctl_rt_secret_interval,
+		.strategy	= &ipv4_sysctl_rt_secret_interval_strategy,
 	},
 	{ .ctl_name = 0 }
 };
@@ -3126,10 +3188,12 @@ static __net_init int rt_secret_timer_init(struct net *net)
 	net->ipv4.rt_secret_timer.data = (unsigned long)net;
 	init_timer_deferrable(&net->ipv4.rt_secret_timer);
 
-	net->ipv4.rt_secret_timer.expires =
-		jiffies + net_random() % ip_rt_secret_interval +
-		ip_rt_secret_interval;
-	add_timer(&net->ipv4.rt_secret_timer);
+	if (ip_rt_secret_interval) {
+		net->ipv4.rt_secret_timer.expires =
+			jiffies + net_random() % ip_rt_secret_interval +
+			ip_rt_secret_interval;
+		add_timer(&net->ipv4.rt_secret_timer);
+	}
 	return 0;
 }