Enable intermediate network drivers like bonding to get or set a
VLAN tag in an skb without a need to know about how tagging is done
according to a network adapter's capabilities.
diff -Nuarp a/include/linux/if_vlan.h b/include/linux/if_vlan.h
--- a/include/linux/if_vlan.h Wed Jan 21 16:56:09 2004
+++ b/include/linux/if_vlan.h Wed Jan 21 16:56:11 2004
@@ -200,6 +200,152 @@ static inline int vlan_hwaccel_receive_s
{
return __vlan_hwaccel_rx(skb, grp, vlan_tag, 1);
}
+
+/**
+ * __vlan_put_tag - regular VLAN tag inserting
+ * @skb: skbuff to tag
+ * @tag: VLAN tag to insert
+ *
+ * Inserts the VLAN tag into @skb as part of the payload
+ * 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.
+ */
+static inline struct sk_buff *__vlan_put_tag(struct sk_buff *skb, unsigned
short tag)
+{
+ struct vlan_ethhdr *veth;
+
+ if (skb_headroom(skb) < VLAN_HLEN) {
+ struct sk_buff *sk_tmp = skb;
+ skb = skb_realloc_headroom(sk_tmp, VLAN_HLEN);
+ kfree_skb(sk_tmp);
+ if (!skb) {
+ printk(KERN_ERR "vlan: failed to realloc headroom\n");
+ return NULL;
+ }
+ } else {
+ skb = skb_unshare(skb, GFP_ATOMIC);
+ if (!skb) {
+ printk(KERN_ERR "vlan: failed to unshare skbuff\n");
+ 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 * VLAN_ETH_ALEN);
+
+ /* first, the ethernet type */
+ veth->h_vlan_proto = __constant_htons(ETH_P_8021Q);
+
+ /* now, the tag */
+ veth->h_vlan_TCI = htons(tag);
+
+ skb->protocol = __constant_htons(ETH_P_8021Q);
+ skb->mac.raw -= VLAN_HLEN;
+ skb->nh.raw -= VLAN_HLEN;
+
+ return skb;
+}
+
+/**
+ * __vlan_hwaccel_put_tag - hardware accelerated VLAN inserting
+ * @skb: skbuff to tag
+ * @tag: VLAN tag to insert
+ *
+ * Puts the VLAN tag in @skb->cb[] and lets the device do the rest
+ */
+static inline struct sk_buff *__vlan_hwaccel_put_tag(struct sk_buff *skb,
unsigned short tag)
+{
+ struct vlan_skb_tx_cookie *cookie;
+
+ cookie = VLAN_TX_SKB_CB(skb);
+ cookie->magic = VLAN_TX_COOKIE_MAGIC;
+ cookie->vlan_tag = tag;
+
+ return skb;
+}
+
+#define HAVE_VLAN_PUT_TAG
+
+/**
+ * vlan_put_tag - inserts VLAN tag according to device features
+ * @skb: skbuff to tag
+ * @tag: VLAN tag to insert
+ *
+ * Assumes skb->dev is the target that will xmit this frame.
+ * Returns a VLAN tagged skb.
+ */
+static inline struct sk_buff *vlan_put_tag(struct sk_buff *skb, unsigned short
tag)
+{
+ if (skb->dev->features & NETIF_F_HW_VLAN_TX) {
+ return __vlan_hwaccel_put_tag(skb, tag);
+ } else {
+ return __vlan_put_tag(skb, tag);
+ }
+}
+
+/**
+ * __vlan_get_tag - get the VLAN ID that is part of the payload
+ * @skb: skbuff to query
+ * @tag: buffer to store vlaue
+ *
+ * Returns error if the skb is not of VLAN type
+ */
+static inline int __vlan_get_tag(struct sk_buff *skb, unsigned short *tag)
+{
+ struct vlan_ethhdr *veth = (struct vlan_ethhdr *)skb->data;
+
+ if (veth->h_vlan_proto != __constant_htons(ETH_P_8021Q)) {
+ return -EINVAL;
+ }
+
+ *tag = ntohs(veth->h_vlan_TCI);
+
+ return 0;
+}
+
+/**
+ * __vlan_hwaccel_get_tag - get the VLAN ID that is in @skb->cb[]
+ * @skb: skbuff to query
+ * @tag: buffer to store vlaue
+ *
+ * Returns error if @skb->cb[] is not set correctly
+ */
+static inline int __vlan_hwaccel_get_tag(struct sk_buff *skb, unsigned short
*tag)
+{
+ struct vlan_skb_tx_cookie *cookie;
+
+ cookie = VLAN_TX_SKB_CB(skb);
+ if (cookie->magic == VLAN_TX_COOKIE_MAGIC) {
+ *tag = cookie->vlan_tag;
+ return 0;
+ } else {
+ *tag = 0;
+ return -EINVAL;
+ }
+}
+
+#define HAVE_VLAN_GET_TAG
+
+/**
+ * vlan_get_tag - get the VLAN ID from the skb
+ * @skb: skbuff to query
+ * @tag: buffer to store vlaue
+ *
+ * Returns error if the skb is not VLAN tagged
+ */
+static inline int vlan_get_tag(struct sk_buff *skb, unsigned short *tag)
+{
+ if (skb->dev->features & NETIF_F_HW_VLAN_TX) {
+ return __vlan_hwaccel_get_tag(skb, tag);
+ } else {
+ return __vlan_get_tag(skb, tag);
+ }
+}
+
#endif /* __KERNEL__ */
/* VLAN IOCTLs are found in sockios.h */
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