diff --git a/include/netinet/ip.h b/include/netinet/ip.h
index aa8b98ca06..8aa9660a25 100644
--- a/include/netinet/ip.h
+++ b/include/netinet/ip.h
@@ -32,6 +32,33 @@
  * Public Type Definitions
  ****************************************************************************/
 
+#define IPVERSION 4     /* IP version number */
+#define IPDEFTTL  64    /* default ttl, from RFC 1340 */
+
+struct iphdr
+{
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+  unsigned int ihl:4;
+  unsigned int version:4;
+#elif __BYTE_ORDER == __BIG_ENDIAN
+  unsigned int version:4;
+  unsigned int ihl:4;
+#else
+# error "unknown endian"
+#endif
+  uint8_t tos;
+  uint16_t tot_len;
+  uint16_t id;
+  uint16_t frag_off;
+  uint8_t ttl;
+  uint8_t protocol;
+  uint16_t check;
+  uint32_t saddr;
+  uint32_t daddr;
+
+  /* The options start here. */
+};
+
 /****************************************************************************
  * Public Function Prototypes
  ****************************************************************************/