vlan: fix network_header/mac_header adjustments

Lennert Buytenhek points out that the VLAN code incorrectly adjusts
skb->network_header to point in the middle of the VLAN header and
additionally tries to adjust skb->mac_header without checking for
validity.

The network_header should not be touched at all since we're only
adding headers in front of it, mac_header adjustments are not
necessary at all.

Based on patch by Lennert Buytenhek <buytenh@wantstofly.org>.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 0 insertions, 3 deletions

diff --git a/include/linux/if_vlan.h b/include/linux/if_vlan.h
index 5190452ac7dc..8f5bf9b676aa 100644
--- a/include/linux/if_vlan.h
+++ b/include/linux/if_vlan.h
@@ -279,8 +279,6 @@ static inline struct sk_buff *__vlan_put_tag(struct sk_buff *skb, unsigned short
         veth->h_vlan_TCI = htons(tag);
 
         skb->protocol = htons(ETH_P_8021Q);
-        skb->mac_header -= VLAN_HLEN;
-        skb->network_header -= VLAN_HLEN;
 
         return skb;
 }
diff --git a/net/8021q/vlan_dev.c b/net/8021q/vlan_dev.c
index a0617bf7cec6..4a8525927c27 100644
--- a/net/8021q/vlan_dev.c
+++ b/net/8021q/vlan_dev.c
@@ -308,7 +308,6 @@ static int vlan_dev_hard_header(struct sk_buff *skb, struct net_device *dev,
                         vhdr->h_vlan_encapsulated_proto = htons(len);
 
                 skb->protocol = htons(ETH_P_8021Q);
-                skb_reset_network_header(skb);
         }
 
         /* Before delegating work to the lower layer, enter our MAC-address */