net: move vlan pop/push functions into common code

So it can be used from out of openvswitch code.
Did couple of cosmetic changes on the way, namely variable naming and
adding support for 8021AD proto.

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 95 insertions, 0 deletions

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index d11bbe0..c906c5f4 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -4163,6 +4163,101 @@ int skb_ensure_writable(struct sk_buff *skb, int write_len)
 }
 EXPORT_SYMBOL(skb_ensure_writable);
 
+/* remove VLAN header from packet and update csum accordingly. */
+static int __skb_vlan_pop(struct sk_buff *skb, u16 *vlan_tci)
+{
+	struct vlan_hdr *vhdr;
+	unsigned int offset = skb->data - skb_mac_header(skb);
+	int err;
+
+	__skb_push(skb, offset);
+	err = skb_ensure_writable(skb, VLAN_ETH_HLEN);
+	if (unlikely(err))
+		goto pull;
+
+	skb_postpull_rcsum(skb, skb->data + (2 * ETH_ALEN), VLAN_HLEN);
+
+	vhdr = (struct vlan_hdr *)(skb->data + ETH_HLEN);
+	*vlan_tci = ntohs(vhdr->h_vlan_TCI);
+
+	memmove(skb->data + VLAN_HLEN, skb->data, 2 * ETH_ALEN);
+	__skb_pull(skb, VLAN_HLEN);
+
+	vlan_set_encap_proto(skb, vhdr);
+	skb->mac_header += VLAN_HLEN;
+
+	if (skb_network_offset(skb) < ETH_HLEN)
+		skb_set_network_header(skb, ETH_HLEN);
+
+	skb_reset_mac_len(skb);
+pull:
+	__skb_pull(skb, offset);
+
+	return err;
+}
+
+int skb_vlan_pop(struct sk_buff *skb)
+{
+	u16 vlan_tci;
+	__be16 vlan_proto;
+	int err;
+
+	if (likely(vlan_tx_tag_present(skb))) {
+		skb->vlan_tci = 0;
+	} else {
+		if (unlikely((skb->protocol != htons(ETH_P_8021Q) &&
+			      skb->protocol != htons(ETH_P_8021AD)) ||
+			     skb->len < VLAN_ETH_HLEN))
+			return 0;
+
+		err = __skb_vlan_pop(skb, &vlan_tci);
+		if (err)
+			return err;
+	}
+	/* move next vlan tag to hw accel tag */
+	if (likely((skb->protocol != htons(ETH_P_8021Q) &&
+		    skb->protocol != htons(ETH_P_8021AD)) ||
+		   skb->len < VLAN_ETH_HLEN))
+		return 0;
+
+	vlan_proto = skb->protocol;
+	err = __skb_vlan_pop(skb, &vlan_tci);
+	if (unlikely(err))
+		return err;
+
+	__vlan_hwaccel_put_tag(skb, vlan_proto, vlan_tci);
+	return 0;
+}
+EXPORT_SYMBOL(skb_vlan_pop);
+
+int skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci)
+{
+	if (vlan_tx_tag_present(skb)) {
+		unsigned int offset = skb->data - skb_mac_header(skb);
+		int err;
+
+		/* __vlan_insert_tag expect skb->data pointing to mac header.
+		 * So change skb->data before calling it and change back to
+		 * original position later
+		 */
+		__skb_push(skb, offset);
+		err = __vlan_insert_tag(skb, skb->vlan_proto,
+					vlan_tx_tag_get(skb));
+		if (err)
+			return err;
+		skb->protocol = skb->vlan_proto;
+		skb->mac_len += VLAN_HLEN;
+		__skb_pull(skb, offset);
+
+		if (skb->ip_summed == CHECKSUM_COMPLETE)
+			skb->csum = csum_add(skb->csum, csum_partial(skb->data
+					+ (2 * ETH_ALEN), VLAN_HLEN, 0));
+	}
+	__vlan_hwaccel_put_tag(skb, vlan_proto, vlan_tci);
+	return 0;
+}
+EXPORT_SYMBOL(skb_vlan_push);
+
 /**
  * alloc_skb_with_frags - allocate skb with page frags
  *