net: tcp: fix rtable leak in tcp_is_local[6]

ip_rt_put/ip6_rt_put call is missed after route lookup routine.
So if lookup returns ok, rtable leak will happen.

Change-Id: Ica137043879b4305b70401cf7e8efda24405e3ff
Signed-off-by: Liping Zhang <liping.zhang@spreadtrum.com>

net/ipv4/tcp.c

@@ -3501,16 +3501,24 @@ void __init tcp_init(void)
 static int tcp_is_local(struct net *net, __be32 addr) {
 	struct rtable *rt;
 	struct flowi4 fl4 = { .daddr = addr };
+	int is_local;
 	rt = ip_route_output_key(net, &fl4);
 	if (IS_ERR_OR_NULL(rt))
 		return 0;
-	return rt->dst.dev && (rt->dst.dev->flags & IFF_LOOPBACK);
+
+	is_local = rt->dst.dev && (rt->dst.dev->flags & IFF_LOOPBACK);
+	ip_rt_put(rt);
+	return is_local;
 }
 
 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 static int tcp_is_local6(struct net *net, struct in6_addr *addr) {
 	struct rt6_info *rt6 = rt6_lookup(net, addr, addr, 0, 0);
-	return rt6 && rt6->dst.dev && (rt6->dst.dev->flags & IFF_LOOPBACK);
+	int is_local;
+
+	is_local = rt6 && rt6->dst.dev && (rt6->dst.dev->flags & IFF_LOOPBACK);
+	ip6_rt_put(rt6);
+	return is_local;
 }
 #endif