/* netinet/ip.h
 * definitions for ipv4 protocol
 */
 
#ifndef _NETINET_IP_H
#define _NETINET_IP_H

#include <netinet/in.h>
#include <stdint.h>

/* Based on RFC 791 */

#define IPVERSION 4

struct ip {
#if     BYTE_ORDER == BIG_ENDIAN
        uint8_t                 ip_v:4;
        uint8_t                 ip_hl:4;
#elif   BYTE_ORDER == LITTLE_ENDIAN
        uint8_t                 ip_hl:4;
        uint8_t                 ip_v:4;
#endif
        uint8_t                 ip_tos;
        uint16_t                ip_len;
        uint16_t                ip_id;
        int16_t                 ip_off;
        uint8_t                 ip_ttl;
        uint8_t                 ip_p;
        uint16_t                ip_sum;
        struct in_addr  ip_src;
        struct in_addr  ip_dst;
} _PACKED;

#define IP_MAXPACKET   65535/* Maximum packet size */

/* IP Type of Service */
#define IPTOS_RELIABILITY   0x04
#define IPTOS_THROUGHPUT    0x08
#define IPTOS_LOWDELAY      0x10

/*
 * Definitions for options.
 */
#define IPOPT_COPIED(o)((o)&0x80)
#define IPOPT_CLASS(o)((o)&0x60)
#define IPOPT_NUMBER(o)((o)&0x1f)

#define IPOPT_CONTROL            0x00
#define IPOPT_RESERVED1          0x20
#define IPOPT_DEBMEAS            0x40
#define IPOPT_RESERVED2          0x60

#define IPOPT_EOL                   0/* end of option list */
#define IPOPT_NOP                   1/* no operation */

#define IPOPT_RR                    7/* record packet route */
#define IPOPT_TS                   68/* timestamp */
#define IPOPT_SECURITY            130/* provide s,c,h,tcc */
#define IPOPT_LSRR                131/* loose source route */
#define IPOPT_SATID               136/* satnet id */
#define IPOPT_SSRR                137/* strict source route */  

/*
 * Offsets to fields in options other than EOL and NOP.
 */
#define IPOPT_OPTVAL                0/* option ID */
#define IPOPT_OLEN                  1/* option length */
#define IPOPT_OFFSET                2/* offset within option */
#define IPOPT_MINOFF                4/* min value of above */   

struct  ip_timestamp {
        uint8_t ipt_code;/* IPOPT_TS */
        uint8_t ipt_len;/* size of structure (variable) */
        uint8_t ipt_ptr;/* index of current entry */
#if     BYTE_ORDER == BIG_ENDIAN
        uint8_t ipt_oflw:4,
                        ipt_flg:4;
#elif   BYTE_ORDER == LITTLE_ENDIAN
        uint8_t ipt_flg:4,
                        ipt_oflw:4;
#endif
        union ipt_timestamp {
                uint32_t ipt_time[1];
                struct ipt_ta {
                        struct in_addr ipt_addr;
                        uint32_t ipt_time;
                } ipt_ta;
        } ipt_timestamp;
}; 

/* flag bits for ipt_flg */
#define IPOPT_TS_TSONLY      0/* timestamps only */
#define IPOPT_TS_TSANDADDR   1/* timestamps and addresses */
#define IPOPT_TS_PRESPEC     3/* specified modules only */

/* bits for security (not byte swapped) */
#define IPOPT_SECUR_UNCLASS     0x0000
#define IPOPT_SECUR_CONFID      0xf135
#define IPOPT_SECUR_EFTO        0x789a
#define IPOPT_SECUR_MMMM        0xbc4d
#define IPOPT_SECUR_RESTR       0xaf13
#define IPOPT_SECUR_SECRET      0xd788
#define IPOPT_SECUR_TOPSECRET   0x6bc5 

#define MAXTTL                  255/* maximum time to live (seconds) */
#define IPDEFTTL                64/* default ttl, from RFC 1340 */
#define IPFRAGTTL               60/* time to live for frags, slowhz */
#define IPTTLDEC                1/* subtracted when forwarding */

#define IP_MSS                  576/* default maximum segment size */  

struct ippseudo {
        struct    in_addr ippseudo_src; /* source internet address */
        struct    in_addr ippseudo_dst; /* destination internet address */
        uint8_t   ippseudo_pad;/* pad, must be zero */
        uint8_t   ippseudo_p;/* protocol */
        uint16_t  ippseudo_len;/* protocol length */
};  

/* Fragment flags */
#define IP_DF 0x4000        /* don't fragment */
#define IP_MF 0x2000        /* more fragments */
#define IP_OFFMASK 0x1fff

#endif /* NETINET_IP_H */