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vlan: Fix out of order vlan headers with reorder header off

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With reorder header off, received packets are untagged in skb_vlan_untag()
called from within __netif_receive_skb_core(), and later the tag will be
inserted back in vlan_do_receive().

This caused out of order vlan headers when we create a vlan device on top
of another vlan device, because vlan_do_receive() inserts a tag as the
outermost vlan tag. E.g. the outer tag is first removed in skb_vlan_untag()
and inserted back in vlan_do_receive(), then the inner tag is next removed
and inserted back as the outermost tag.

This patch fixes the behaviour by inserting the inner tag at the right
position.

Signed-off-by: Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Toshiaki Makita 2018-03-13 14:51:28 +09:00 committed by David S. Miller
parent 4bbb3e0e82
commit cbe7128c4b
2 changed files with 70 additions and 26 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

92
include/linux/if_vlan.h
View file

@ -299,6 +299,44 @@ static inline bool vlan_hw_offload_capable(netdev_features_t features,
return false;
}
/**
* __vlan_insert_inner_tag - inner VLAN tag inserting
* @skb: skbuff to tag
* @vlan_proto: VLAN encapsulation protocol
* @vlan_tci: VLAN TCI to insert
* @mac_len: MAC header length including outer vlan headers
*
* Inserts the VLAN tag into @skb as part of the payload at offset mac_len
* 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_inner_tag(struct sk_buff *skb,
__be16 vlan_proto, u16 vlan_tci,
unsigned int mac_len)
{
struct vlan_ethhdr *veth;
if (skb_cow_head(skb, VLAN_HLEN) < 0)
return -ENOMEM;
skb_push(skb, VLAN_HLEN);
/* Move the mac header sans proto to the beginning of the new header. */
memmove(skb->data, skb->data + VLAN_HLEN, mac_len - ETH_TLEN);
skb->mac_header -= VLAN_HLEN;
veth = (struct vlan_ethhdr *)(skb->data + mac_len - ETH_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
@ -313,24 +351,37 @@ static inline bool vlan_hw_offload_capable(netdev_features_t features,
static inline int __vlan_insert_tag(struct sk_buff *skb,
__be16 vlan_proto, u16 vlan_tci)
{
struct vlan_ethhdr *veth;
return __vlan_insert_inner_tag(skb, vlan_proto, vlan_tci, ETH_HLEN);
}
if (skb_cow_head(skb, VLAN_HLEN) < 0)
return -ENOMEM;
/**
* vlan_insert_inner_tag - inner VLAN tag inserting
* @skb: skbuff to tag
* @vlan_proto: VLAN encapsulation protocol
* @vlan_tci: VLAN TCI to insert
* @mac_len: MAC header length including outer vlan headers
*
* Inserts the VLAN tag into @skb as part of the payload at offset mac_len
* Returns a VLAN tagged skb. If a new skb is created, @skb is freed.
*
* Following the skb_unshare() example, in case of error, the calling function
* doesn't have to worry about freeing the original skb.
*
* Does not change skb->protocol so this function can be used during receive.
*/
static inline struct sk_buff *vlan_insert_inner_tag(struct sk_buff *skb,
__be16 vlan_proto,
u16 vlan_tci,
unsigned int mac_len)
{
int err;
veth = 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;
err = __vlan_insert_inner_tag(skb, vlan_proto, vlan_tci, mac_len);
if (err) {
dev_kfree_skb_any(skb);
return NULL;
}
return skb;
}
/**
@ -350,14 +401,7 @@ static inline int __vlan_insert_tag(struct sk_buff *skb,
static inline struct sk_buff *vlan_insert_tag(struct sk_buff *skb,
__be16 vlan_proto, u16 vlan_tci)
{
int err;
err = __vlan_insert_tag(skb, vlan_proto, vlan_tci);
if (err) {
dev_kfree_skb_any(skb);
return NULL;
}
return skb;
return vlan_insert_inner_tag(skb, vlan_proto, vlan_tci, ETH_HLEN);
}
/**

4
net/8021q/vlan_core.c
View file

@ -48,8 +48,8 @@ bool vlan_do_receive(struct sk_buff **skbp)
* original position later
*/
skb_push(skb, offset);
skb = *skbp = vlan_insert_tag(skb, skb->vlan_proto,
skb->vlan_tci);
skb = *skbp = vlan_insert_inner_tag(skb, skb->vlan_proto,
skb->vlan_tci, skb->mac_len);
if (!skb)
return false;
skb_pull(skb, offset + VLAN_HLEN);