+#if LINUX_VERSION_CODE < VERSION(2,1,86)
+#define KFREE_SKB(s) dev_kfree_skb((s), FREE_WRITE)
+#else
+#define KFREE_SKB(s) kfree_skb(s)
+#endif
+
+#if LINUX_VERSION_CODE < VERSION(2,1,15)
+#define LIBERATE_SKB(s) ((s)->free = 1)
+#else
+#define LIBERATE_SKB(s) do { } while (0)
+#endif
+
+#if LINUX_VERSION_CODE < VERSION(2,1,95)
+#define SUSER() suser()
+#else
+#define SUSER() capable(CAP_NET_ADMIN)
+#endif
+