50 struct ip {  struct
51 	u_int8_t	ip_vhl;		/* header length, version */  argument
52 #define IP_V(ip)	(((ip)->ip_vhl & 0xf0) >> 4)  argument
53 #define IP_HL(ip)	((ip)->ip_vhl & 0x0f)  argument
54 	u_int8_t	ip_tos;		/* type of service */  argument
55 	u_int16_t	ip_len;		/* total length */  argument
56 	u_int16_t	ip_id;		/* identification */  argument
57 	u_int16_t	ip_off;		/* fragment offset field */  argument
61 	u_int8_t	ip_ttl;		/* time to live */  argument
62 	u_int8_t	ip_p;		/* protocol */  argument
63 	u_int16_t	ip_sum;		/* checksum */  argument
64 	struct	in_addr ip_src,ip_dst;	/* source and dest address */  argument
128 #define IPTS_OFLW(ip)	(((ipt)->ipt_oflwflg & 0xf0) >> 4)  argument
129 #define IPTS_FLG(ip)	((ipt)->ipt_oflwflg & 0x0f)  argument