Index: linux-2.6.21.7/include/linux/ip.h
===================================================================
--- linux-2.6.21.7.orig/include/linux/ip.h
+++ linux-2.6.21.7/include/linux/ip.h
@@ -104,6 +104,16 @@ struct iphdr {
 	/*The options start here. */
 };
 
+#ifdef __KERNEL__
+#include <linux/skbuff.h>
+
+static inline struct iphdr *ip_hdr(const struct sk_buff *skb)
+{
+	return (struct iphdr *)skb_network_header(skb);
+}
+
+#endif
+
 struct ip_auth_hdr {
 	__u8  nexthdr;
 	__u8  hdrlen;		/* This one is measured in 32 bit units! */
Index: linux-2.6.21.7/include/linux/skbuff.h
===================================================================
--- linux-2.6.21.7.orig/include/linux/skbuff.h
+++ linux-2.6.21.7/include/linux/skbuff.h
@@ -966,6 +966,16 @@ static inline void skb_reserve(struct sk
 	skb->tail += len;
 }
 
+static inline unsigned char *skb_network_header(const struct sk_buff *skb)
+{
+	return skb->nh.raw;
+}
+
+static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
+{
+	return skb->tail;
+}
+
 /*
  * CPUs often take a performance hit when accessing unaligned memory
  * locations. The actual performance hit varies, it can be small if the
Index: linux-2.6.21.7/include/net/ip.h
===================================================================
--- linux-2.6.21.7.orig/include/net/ip.h
+++ linux-2.6.21.7/include/net/ip.h
@@ -43,6 +43,11 @@ struct inet_skb_parm
 #define IPSKB_REROUTED		16
 };
 
+static inline unsigned int ip_hdrlen(const struct sk_buff *skb)
+{
+	return ip_hdr(skb)->ihl * 4;
+}
+
 struct ipcm_cookie
 {
 	__be32			addr;