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vlan: introduce __vlan_insert_tag helper which does not free skb 

There's a need for helper which inserts vlan tag but does not free the
skb in case of an error.

Suggested-by: Pravin Shelar <pshelar@nicira.com>
Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Acked-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jiri Pirko 2014-11-19 14:05:00 +01:00 committed by David S. Miller
parent 5968250c86
commit 15255a43e6
1 changed files with 37 additions and 14 deletions
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51
include/linux/if_vlan.h
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@ -281,6 +281,40 @@ static inline bool vlan_hw_offload_capable(netdev_features_t features,
return false;
}
/**
* __vlan_insert_tag - regular VLAN tag inserting
* @skb: skbuff to tag
* @vlan_proto: VLAN encapsulation protocol
* @vlan_tci: VLAN TCI to insert
*
* Inserts the VLAN tag into @skb as part of the payload
* Returns error if skb_cow_head failes.
*
* Does not change skb->protocol so this function can be used during receive.
*/
static inline int __vlan_insert_tag(struct sk_buff *skb,
__be16 vlan_proto, u16 vlan_tci)
{
struct vlan_ethhdr *veth;
if (skb_cow_head(skb, VLAN_HLEN) < 0)
return -ENOMEM;
veth = (struct vlan_ethhdr *)skb_push(skb, VLAN_HLEN);
/* Move the mac addresses to the beginning of the new header. */
memmove(skb->data, skb->data + VLAN_HLEN, 2 * ETH_ALEN);
skb->mac_header -= VLAN_HLEN;
/* first, the ethernet type */
veth->h_vlan_proto = vlan_proto;
/* now, the TCI */
veth->h_vlan_TCI = htons(vlan_tci);
return 0;
}
/**
* vlan_insert_tag - regular VLAN tag inserting
* @skb: skbuff to tag
@ -298,24 +332,13 @@ static inline bool vlan_hw_offload_capable(netdev_features_t features,
static inline struct sk_buff *vlan_insert_tag(struct sk_buff *skb,
__be16 vlan_proto, u16 vlan_tci)
{
struct vlan_ethhdr *veth;
int err;
if (skb_cow_head(skb, VLAN_HLEN) < 0) {
err = __vlan_insert_tag(skb, vlan_proto, vlan_tci);
if (err) {
dev_kfree_skb_any(skb);
return NULL;
}
veth = (struct vlan_ethhdr *)skb_push(skb, VLAN_HLEN);
/* Move the mac addresses to the beginning of the new header. */
memmove(skb->data, skb->data + VLAN_HLEN, 2 * ETH_ALEN);
skb->mac_header -= VLAN_HLEN;
/* first, the ethernet type */
veth->h_vlan_proto = vlan_proto;
/* now, the TCI */
veth->h_vlan_TCI = htons(vlan_tci);
return skb;
}