71 struct ip {  struct
72 	u_char  ip_v:4,			/* version */  argument
73 		ip_hl:4;		/* header length */  argument
74 	u_char  ip_tos;			/* type of service */  argument
75 	short   ip_len;			/* total length */  argument
76 	u_short ip_id;			/* identification */  argument
77 	short   ip_off;			/* fragment offset field */  argument
81 	u_char  ip_ttl;			/* time to live */  argument
82 	u_char  ip_p;			/* protocol */  argument
83 	u_short ip_sum;			/* checksum */  argument
84 	u_char  ip_src[4];  argument
85 	u_char  ip_dst[4];		/* source and dest address */  argument