--- /dev/null
+#ifndef _IP6T_AH_H
+#define _IP6T_AH_H
+
+struct ip6t_ah
+{
+ u_int32_t spis[2]; /* Security Parameter Index */
+ u_int32_t hdrlen; /* Header Length */
+ u_int8_t hdrres; /* Test of the Reserved Filed */
+ u_int8_t invflags; /* Inverse flags */
+};
+
+#define IP6T_AH_SPI 0x01
+#define IP6T_AH_LEN 0x02
+#define IP6T_AH_RES 0x04
+
+/* Values for "invflags" field in struct ip6t_ah. */
+#define IP6T_AH_INV_SPI 0x01 /* Invert the sense of spi. */
+#define IP6T_AH_INV_LEN 0x02 /* Invert the sense of length. */
+#define IP6T_AH_INV_MASK 0x03 /* All possible flags. */
+
+#endif /*_IP6T_AH_H*/