vlan: Fix out of order vlan headers with reorder header off
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>
diff --git a/include/linux/if_vlan.h b/include/linux/if_vlan.h
index 5e6a2d4..c4a1cff 100644
--- a/include/linux/if_vlan.h
+++ b/include/linux/if_vlan.h
@@ -300,6 +300,44 @@ static inline bool vlan_hw_offload_capable(netdev_features_t features,
}
/**
+ * __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
* @vlan_proto: VLAN encapsulation protocol
@@ -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);
}
/**