45 struct IP4Hdr  struct
47     uint8_t ip_verhl;      /* version & header length */
48     uint8_t ip_tos;        /* type of service */
49     uint16_t ip_len;       /* datagram length */
50     uint16_t ip_id;        /* identification  */
51     uint16_t ip_off;       /* fragment offset */
52     uint8_t ip_ttl;        /* time to live field */
53     IpProtocol ip_proto;      /* datagram protocol */
54     uint16_t ip_csum;      /* checksum */
55     uint32_t ip_src;  /* source IP */
56     uint32_t ip_dst;  /* dest IP */
59     inline uint8_t hlen() const  in hlen()
62     inline uint8_t ver() const  in ver()
65     inline uint8_t tos() const  in tos()
68     inline uint16_t len() const  in len()
71     inline uint8_t ttl() const  in ttl()
74     inline IpProtocol proto() const  in proto()
77     inline uint16_t off_w_flags() const  in off_w_flags()
80     inline uint16_t rb() const  in rb()
83     inline uint16_t df() const  in df()
86     inline uint16_t mf() const  in mf()
89     inline uint16_t off() const  in off()
92     inline uint16_t id() const  in id()
95     inline uint8_t get_opt_len() const  in get_opt_len()
98     inline uint16_t csum() const  in csum()
102     inline bool is_src_broadcast() const  in is_src_broadcast()
105     inline bool is_dst_broadcast() const  in is_dst_broadcast()
108     inline bool has_options() const  in has_options()
112     inline uint16_t raw_len() const  in raw_len()
115     inline uint16_t raw_id() const  in raw_id()
118     inline uint16_t raw_off() const  in raw_off()
121     inline uint16_t raw_csum() const  in raw_csum()
124     inline uint32_t get_src() const  in get_src()
127     inline uint32_t get_dst() const  in get_dst()
131     inline void set_hlen(uint8_t value)  in set_hlen()
134     inline void set_proto(IpProtocol prot)  in set_proto()
137     inline void set_ip_len(uint16_t new_len)  in set_ip_len()