releases/3.19.2/ipv6-fix-ipv6_cow_metrics-for-non-dst_host-case.patch

   1 From foo@baz Wed Mar 11 11:44:33 CET 2015
   2 From: Martin KaFai Lau <kafai@fb.com>
   3 Date: Thu, 12 Feb 2015 16:14:08 -0800
   4 Subject: ipv6: fix ipv6_cow_metrics for non DST_HOST case
   5
   6 From: Martin KaFai Lau <kafai@fb.com>
   7
   8 [ Upstream commit 3b4711757d7903ab6fa88a9e7ab8901b8227da60 ]
   9
  10 ipv6_cow_metrics() currently assumes only DST_HOST routes require
  11 dynamic metrics allocation from inetpeer.  The assumption breaks
  12 when ndisc discovered router with RTAX_MTU and RTAX_HOPLIMIT metric.
  13 Refer to ndisc_router_discovery() in ndisc.c and note that dst_metric_set()
  14 is called after the route is created.
  15
  16 This patch creates the metrics array (by calling dst_cow_metrics_generic) in
  17 ipv6_cow_metrics().
  18
  19 Test:
  20 radvd.conf:
  21 interface qemubr0
  22 {
  23         AdvLinkMTU 1300;
  24         AdvCurHopLimit 30;
  25
  26         prefix fd00:face:face:face::/64
  27         {
  28                 AdvOnLink on;
  29                 AdvAutonomous on;
  30                 AdvRouterAddr off;
  31         };
  32 };
  33
  34 Before:
  35 [root@qemu1 ~]# ip -6 r show | egrep -v unreachable
  36 fd00:face:face:face::/64 dev eth0  proto kernel  metric 256  expires 27sec
  37 fe80::/64 dev eth0  proto kernel  metric 256
  38 default via fe80::74df:d0ff:fe23:8ef2 dev eth0  proto ra  metric 1024  expires 27sec
  39
  40 After:
  41 [root@qemu1 ~]# ip -6 r show | egrep -v unreachable
  42 fd00:face:face:face::/64 dev eth0  proto kernel  metric 256  expires 27sec mtu 1300
  43 fe80::/64 dev eth0  proto kernel  metric 256  mtu 1300
  44 default via fe80::74df:d0ff:fe23:8ef2 dev eth0  proto ra  metric 1024  expires 27sec mtu 1300 hoplimit 30
  45
  46 Fixes: 8e2ec639173f325 (ipv6: don't use inetpeer to store metrics for routes.)
  47 Signed-off-by: Martin KaFai Lau <kafai@fb.com>
  48 Signed-off-by: David S. Miller <davem@davemloft.net>
  49 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  50 ---
  51  net/ipv6/route.c |    2 +-
  52  1 file changed, 1 insertion(+), 1 deletion(-)
  53
  54 --- a/net/ipv6/route.c
  55 +++ b/net/ipv6/route.c
  56 @@ -141,7 +141,7 @@ static u32 *ipv6_cow_metrics(struct dst_
  57         u32 *p = NULL;
  58
  59         if (!(rt->dst.flags & DST_HOST))
  60 -               return NULL;
  61 +               return dst_cow_metrics_generic(dst, old);
  62
  63         peer = rt6_get_peer_create(rt);
  64         if (peer) {