ipv6 route: Fix lifetime in netlink.

We could not see appropriate lifetime if the route had been scheduled
to expired at 0 (in jiffies).  We should check rt6i_flags instead of
rt6i_expires to determine whether lifetime is valid or not.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/route.c

@@ -2200,7 +2200,9 @@ static int rt6_fill_node(struct sk_buff *skb, struct rt6_info *rt,
 
 	NLA_PUT_U32(skb, RTA_PRIORITY, rt->rt6i_metric);
 
-	expires = rt->rt6i_expires ? rt->rt6i_expires - jiffies : 0;
+	expires = (rt->rt6i_flags & RTF_EXPIRES) ?
+			rt->rt6i_expires - jiffies : 0;
+
 	if (rtnl_put_cacheinfo(skb, &rt->u.dst, 0, 0, 0,
 			       expires, rt->u.dst.error) < 0)
 		goto nla_put_failure;