ipv6: Set default hoplimit as zero.

[ Upstream commit 14edd87d ]

Commit a02e4b7d(Demark default hoplimit as zero) only changes the
hoplimit checking condition and default value in ip6_dst_hoplimit, not
zeros all hoplimit default value.

Keep the zeroing ip6_template_metrics[RTAX_HOPLIMIT - 1] to force it as
const, cause as a37e6e34(net: force dst_default_metrics to const
section)
Signed-off-by: Li RongQing <roy.qing.li@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

net/ipv6/route.c

@@ -171,7 +171,7 @@ static struct dst_ops ip6_dst_blackhole_ops = {
 };
 
 static const u32 ip6_template_metrics[RTAX_MAX] = {
-	[RTAX_HOPLIMIT - 1] = 255,
+	[RTAX_HOPLIMIT - 1] = 0,
 };
 
 static struct rt6_info ip6_null_entry_template = {
@@ -1068,7 +1068,7 @@ struct dst_entry *icmp6_dst_alloc(struct net_device *dev,
 	rt->rt6i_idev     = idev;
 	dst_set_neighbour(&rt->dst, neigh);
 	atomic_set(&rt->dst.__refcnt, 1);
-	dst_metric_set(&rt->dst, RTAX_HOPLIMIT, 255);
+	dst_metric_set(&rt->dst, RTAX_HOPLIMIT, 0);
 	rt->dst.output  = ip6_output;
 
 	spin_lock_bh(&icmp6_dst_lock);