+#define IP6CB(skb) ((struct inet6_skb_parm*)((skb)->cb))
+
+/**
+ * struct ipv6_pinfo - ipv6 private area
+ *
+ * In the struct sock hierarchy (tcp6_sock, upd6_sock, etc)
+ * this _must_ be the last member, so that inet6_sk_generic
+ * is able to calculate its offset from the base struct sock
+ * by using the struct proto->slab_obj_size member. -acme
+ */