path: root/net/8021q
diff options
authorDavid S. Miller <davem@davemloft.net>2013-12-31 16:23:35 -0500
committerDavid S. Miller <davem@davemloft.net>2013-12-31 16:23:35 -0500
commit2205369a314e12fcec4781cc73ac9c08fc2b47de (patch)
tree5daa8338d99f62013631fc9c2ab1a6e6896ef0cd /net/8021q
parent71ce176ee6ed1735b9a1160a5704a915d13849b1 (diff)
vlan: Fix header ops passthru when doing TX VLAN offload.
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>
Diffstat (limited to 'net/8021q')
1 files changed, 18 insertions, 1 deletions
diff --git a/net/8021q/vlan_dev.c b/net/8021q/vlan_dev.c
index 762896ebfcf5..47c908f1f626 100644
--- a/net/8021q/vlan_dev.c
+++ b/net/8021q/vlan_dev.c
@@ -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;

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