[PATCH 3.4 039/172] ipv6: fix ipv6_cow_metrics for non DST_HOST case

lizf
2015-06-16T09:30:09Z

From: Martin KaFai Lau <kafai@fb.com>

3.4.108-rc1 review patch. If anyone has any objections, please let me know.

------------------

commit 3b4711757d7903ab6fa88a9e7ab8901b8227da60 upstream.

ipv6_cow_metrics() currently assumes only DST_HOST routes require
dynamic metrics allocation from inetpeer. The assumption breaks
when ndisc discovered router with RTAX_MTU and RTAX_HOPLIMIT metric.
Refer to ndisc_router_discovery() in ndisc.c and note that dst_metric_set()
is called after the route is created.

This patch creates the metrics array (by calling dst_cow_metrics_generic) in
ipv6_cow_metrics().

Test:
radvd.conf:
interface qemubr0
{
AdvLinkMTU 1300;
AdvCurHopLimit 30;

prefix fd00:face:face:face::/64
{
AdvOnLink on;
AdvAutonomous on;
AdvRouterAddr off;
};
};

Before:
[root@qemu1 ~]# ip -6 r show | egrep -v unreachable
fd00:face:face:face::/64 dev eth0 proto kernel metric 256 expires 27sec
fe80::/64 dev eth0 proto kernel metric 256
default via fe80::74df:d0ff:fe23:8ef2 dev eth0 proto ra metric 1024 expires 27sec

After:
[root@qemu1 ~]# ip -6 r show | egrep -v unreachable
fd00:face:face:face::/64 dev eth0 proto kernel metric 256 expires 27sec mtu 1300
fe80::/64 dev eth0 proto kernel metric 256 mtu 1300
default via fe80::74df:d0ff:fe23:8ef2 dev eth0 proto ra metric 1024 expires 27sec mtu 1300 hoplimit 30

Fixes: 8e2ec639173f325 (ipv6: don't use inetpeer to store metrics for routes.)
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Zefan Li <lizefan@huawei.com>
---
net/ipv6/route.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index c8643a3..4cfba3d 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -95,7 +95,7 @@ static u32 *ipv6_cow_metrics(struct dst_entry *dst, unsigned long old)
u32 *p = NULL;

if (!(rt->dst.flags & DST_HOST))
- return NULL;
+ return dst_cow_metrics_generic(dst, old);

if (!rt->rt6i_peer)
rt6_bind_peer(rt, 1);
--
1.9.1