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vlan: Fix header ops passthru when doing TX VLAN offload.

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When the vlan code detects that the real device can do TX VLAN offloads
in hardware, it tries to arrange for the real device's header_ops to
be invoked directly.

But it does so illegally, by simply hooking the real device's
header_ops up to the VLAN device.

This doesn't work because we will end up invoking a set of header_ops
routines which expect a device type which matches the real device, but
will see a VLAN device instead.

Fix this by providing a pass-thru set of header_ops which will arrange
to pass the proper real device instead.

To facilitate this add a dev_rebuild_header().  There are
implementations which provide a ->cache and ->create but not a
->rebuild (f.e. PLIP).  So we need a helper function just like
dev_hard_header() to avoid crashes.

Use this helper in the one existing place where the
header_ops->rebuild was being invoked, the neighbour code.

With lots of help from Florian Westphal.

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2013-12-31 16:23:35 -05:00
parent 71ce176ee6
commit 2205369a31
3 changed files with 28 additions and 2 deletions
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9
include/linux/netdevice.h
View file

@ -1912,6 +1912,15 @@ static inline int dev_parse_header(const struct sk_buff *skb,
return dev->header_ops->parse(skb, haddr);
}
static inline int dev_rebuild_header(struct sk_buff *skb)
{
const struct net_device *dev = skb->dev;
if (!dev->header_ops || !dev->header_ops->rebuild)
return 0;
return dev->header_ops->rebuild(skb);
}
typedef int gifconf_func_t(struct net_device * dev, char __user * bufptr, int len);
int register_gifconf(unsigned int family, gifconf_func_t *gifconf);
static inline int unregister_gifconf(unsigned int family)

19
net/8021q/vlan_dev.c
View file

@ -530,6 +530,23 @@ static const struct header_ops vlan_header_ops = {
.parse = eth_header_parse,
};
static int vlan_passthru_hard_header(struct sk_buff *skb, struct net_device *dev,
unsigned short type,
const void *daddr, const void *saddr,
unsigned int len)
{
struct vlan_dev_priv *vlan = vlan_dev_priv(dev);
struct net_device *real_dev = vlan->real_dev;
return dev_hard_header(skb, real_dev, type, daddr, saddr, len);
}
static const struct header_ops vlan_passthru_header_ops = {
.create = vlan_passthru_hard_header,
.rebuild = dev_rebuild_header,
.parse = eth_header_parse,
};
static struct device_type vlan_type = {
.name = "vlan",
};
@ -573,7 +590,7 @@ static int vlan_dev_init(struct net_device *dev)
dev->needed_headroom = real_dev->needed_headroom;
if (real_dev->features & NETIF_F_HW_VLAN_CTAG_TX) {
dev->header_ops = real_dev->header_ops;
dev->header_ops = &vlan_passthru_header_ops;
dev->hard_header_len = real_dev->hard_header_len;
} else {
dev->header_ops = &vlan_header_ops;

2
net/core/neighbour.c
View file

@ -1275,7 +1275,7 @@ int neigh_compat_output(struct neighbour *neigh, struct sk_buff *skb)
if (dev_hard_header(skb, dev, ntohs(skb->protocol), NULL, NULL,
skb->len) < 0 &&
dev->header_ops->rebuild(skb))
dev_rebuild_header(skb))
return 0;
return dev_queue_xmit(skb);