releases/3.4.77/vlan-fix-header-ops-passthru-when-doing-tx-vlan-offload.patch

   1 From foo@baz Mon Jan 13 09:28:30 PST 2014
   2 From: "David S. Miller" <davem@davemloft.net>
   3 Date: Tue, 31 Dec 2013 16:23:35 -0500
   4 Subject: vlan: Fix header ops passthru when doing TX VLAN offload.
   5
   6 From: "David S. Miller" <davem@davemloft.net>
   7
   8 [ Upstream commit 2205369a314e12fcec4781cc73ac9c08fc2b47de ]
   9
  10 When the vlan code detects that the real device can do TX VLAN offloads
  11 in hardware, it tries to arrange for the real device's header_ops to
  12 be invoked directly.
  13
  14 But it does so illegally, by simply hooking the real device's
  15 header_ops up to the VLAN device.
  16
  17 This doesn't work because we will end up invoking a set of header_ops
  18 routines which expect a device type which matches the real device, but
  19 will see a VLAN device instead.
  20
  21 Fix this by providing a pass-thru set of header_ops which will arrange
  22 to pass the proper real device instead.
  23
  24 To facilitate this add a dev_rebuild_header().  There are
  25 implementations which provide a ->cache and ->create but not a
  26 ->rebuild (f.e. PLIP).  So we need a helper function just like
  27 dev_hard_header() to avoid crashes.
  28
  29 Use this helper in the one existing place where the
  30 header_ops->rebuild was being invoked, the neighbour code.
  31
  32 With lots of help from Florian Westphal.
  33
  34 Signed-off-by: David S. Miller <davem@davemloft.net>
  35 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  36 ---
  37  include/linux/netdevice.h |    9 +++++++++
  38  net/8021q/vlan_dev.c      |   19 ++++++++++++++++++-
  39  2 files changed, 27 insertions(+), 1 deletion(-)
  40
  41 --- a/include/linux/netdevice.h
  42 +++ b/include/linux/netdevice.h
  43 @@ -1702,6 +1702,15 @@ static inline int dev_parse_header(const
  44         return dev->header_ops->parse(skb, haddr);
  45  }
  46
  47 +static inline int dev_rebuild_header(struct sk_buff *skb)
  48 +{
  49 +       const struct net_device *dev = skb->dev;
  50 +
  51 +       if (!dev->header_ops || !dev->header_ops->rebuild)
  52 +               return 0;
  53 +       return dev->header_ops->rebuild(skb);
  54 +}
  55 +
  56  typedef int gifconf_func_t(struct net_device * dev, char __user * bufptr, int len);
  57  extern int             register_gifconf(unsigned int family, gifconf_func_t * gifconf);
  58  static inline int unregister_gifconf(unsigned int family)
  59 --- a/net/8021q/vlan_dev.c
  60 +++ b/net/8021q/vlan_dev.c
  61 @@ -525,6 +525,23 @@ static const struct header_ops vlan_head
  62         .parse   = eth_header_parse,
  63  };
  64
  65 +static int vlan_passthru_hard_header(struct sk_buff *skb, struct net_device *dev,
  66 +                                    unsigned short type,
  67 +                                    const void *daddr, const void *saddr,
  68 +                                    unsigned int len)
  69 +{
  70 +       struct vlan_dev_priv *vlan = vlan_dev_priv(dev);
  71 +       struct net_device *real_dev = vlan->real_dev;
  72 +
  73 +       return dev_hard_header(skb, real_dev, type, daddr, saddr, len);
  74 +}
  75 +
  76 +static const struct header_ops vlan_passthru_header_ops = {
  77 +       .create  = vlan_passthru_hard_header,
  78 +       .rebuild = dev_rebuild_header,
  79 +       .parse   = eth_header_parse,
  80 +};
  81 +
  82  static const struct net_device_ops vlan_netdev_ops;
  83
  84  static int vlan_dev_init(struct net_device *dev)
  85 @@ -564,7 +581,7 @@ static int vlan_dev_init(struct net_devi
  86
  87         dev->needed_headroom = real_dev->needed_headroom;
  88         if (real_dev->features & NETIF_F_HW_VLAN_TX) {
  89 -               dev->header_ops      = real_dev->header_ops;
  90 +               dev->header_ops      = &vlan_passthru_header_ops;
  91                 dev->hard_header_len = real_dev->hard_header_len;
  92         } else {
  93                 dev->header_ops      = &vlan_header_ops;