datapath: Fix VLAN insertion behavior on Linux 2.6.27 and 2.6.28.

[sliver-openvswitch.git] / datapath / linux-2.6 / compat-2.6 / include / linux / if_vlan.h

diff --git a/datapath/linux-2.6/compat-2.6/include/linux/if_vlan.h b/datapath/linux-2.6/compat-2.6/include/linux/if_vlan.h
new file mode 100644 (file)
index 0000000..3bede93
--- /dev/null
+++ b/datapath/linux-2.6/compat-2.6/include/linux/if_vlan.h
@@ -0,0 +1,46 @@
+#ifndef __LINUX_IF_VLAN_WRAPPER_H
+#define __LINUX_IF_VLAN_WRAPPER_H 1
+
+#include_next <linux/if_vlan.h>
+
+/*
+ * The behavior of __vlan_put_tag() has changed over time:
+ *
+ *      - In 2.6.26 and earlier, it adjusted both MAC and network header
+ *        pointers.  (The latter didn't make any sense.)
+ *
+ *      - In 2.6.27 and 2.6.28, it did not adjust any header pointers at all.
+ *
+ *      - In 2.6.29 and later, it adjusts the MAC header pointer only.
+ *
+ * This is the version from 2.6.33.  We unconditionally substitute this version
+ * to avoid the need to guess whether the version in the kernel tree is
+ * acceptable.
+ */
+#define __vlan_put_tag rpl_vlan_put_tag
+static inline struct sk_buff *__vlan_put_tag(struct sk_buff *skb, u16 vlan_tci)
+{
+       struct vlan_ethhdr *veth;
+
+       if (skb_cow_head(skb, VLAN_HLEN) < 0) {
+               kfree_skb(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 * VLAN_ETH_ALEN);
+       skb->mac_header -= VLAN_HLEN;
+
+       /* first, the ethernet type */
+       veth->h_vlan_proto = htons(ETH_P_8021Q);
+
+       /* now, the TCI */
+       veth->h_vlan_TCI = htons(vlan_tci);
+
+       skb->protocol = htons(ETH_P_8021Q);
+
+       return skb;
+}
+
+#endif /* linux/if_vlan.h wrapper */