+
+/* Linux 2.4 is mostly for openwrt */
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
+#include <linux/bitops.h> /* generic_ffs() used in ip_fw2.c */
+typedef uint32_t __be32;
+typedef uint16_t __be16;
+struct sock;
+struct net;
+struct inet_hashinfo;
+struct sock *inet_lookup(
+ struct inet_hashinfo *hashinfo,
+ const __be32 saddr, const __be16 sport,
+ const __be32 daddr, const __be16 dport,
+ const int dif);
+static int inet_iif(const struct sk_buff *skb);
+struct sock *tcp_v4_lookup(u32 saddr, u16 sport, u32 daddr, u16 dport, int dif);
+#endif /* Linux < 2.6 */
+