55 struct ip {  struct
56 	u_int32_t ip_hl:4,		/* header length */  argument
57 		  ip_v:4;		/* version */  argument
58 	u_int8_t  ip_tos;		/* type of service */  argument
59 	u_int16_t ip_len;		/* total length */  argument
60 	u_int16_t ip_id;		/* identification */  argument
61 	u_int16_t ip_off;		/* fragment offset field */  argument
66 	u_int8_t  ip_ttl;		/* time to live */  argument
67 	u_int8_t  ip_p;			/* protocol */  argument
68 	u_int16_t ip_sum;		/* checksum */  argument
69 	struct	  in_addr ip_src, ip_dst; /* source and dest address */  argument