usr/src/sys/netinet/ip.h

/* ip.h 1.5 81/10/29 */

/*
 * Definitions for internet protocol version 4.
 * Per RFC 791, September 1981.
 */
#define IPVERSION       4

/*
 * Structure of an internet header, naked of options.
 *
 * SHOULD MAKE A VERSION OF THIS FOR KERNEL SO USER
 * VERSION CAN BE union FREE AND INITIALIZABLE.
 */
struct ip {
        u_char  ip_hl:4,                /* header length */
                ip_v:4;                 /* version */
        u_char  ip_tos;                 /* type of service */
/* we copy the IP_MF to ip_tos on input */
#define ip_mff  ip_tos                  /* more fragments flag */
/* by rights, ip_len should be a u_short, but this makes operations */
/* on it very dangerous as comparisons become unsigned and comparing */
/* against negative numbers then fails... we don't expect any > 32767 */
/* byte packets, so pragmatically delcare it to be a short */
        short   ip_len;                 /* total length */
        u_short ip_id;                  /* identification */
/* ip_off should also, by rights, be u_short, ala ip_len */
        short   ip_off;                 /* fragment offset field */
#define IP_DF 0x4000                    /* dont fragment flag */
#define IP_MF 0x2000                    /* more fragments flag */
        u_char  ip_ttl;                 /* time to live */
        u_char  ip_p;                   /* protocol */
        u_short ip_sum;                 /* checksum */
        union {
                struct socket ip_s;     /* source address */
                struct ip *ip_nxt;      /* next fragment */
        } I_sun;
#define ip_src  I_sun.ip_s
#define ip_next I_sun.ip_nxt
        union {
                struct socket ip_d;     /* destination address */
                struct ip *ip_prv;      /* prev fragment */
        } I_dun;
#define ip_dst  I_dun.ip_d
#define ip_prev I_dun.ip_prv
};

/*
 * Definitions for options.
 */
#define IPOPT_COPIED(o)         ((o)&0x80)
#define IPOPT_CLASS(o)          ((o)&0x40)
#define IPOPT_NUMBER(o)         ((o)&0x3f)

#define IPOPT_CONTROL           0x00
#define IPOPT_RESERVED1         0x10
#define IPOPT_DEBMEAS           0x20
#define IPOPT_RESERVED2         0x30

#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 */

/*
 * Time stamp option structure.
 */
struct  ip_timestamp {
        u_char  ipt_code;               /* IPOPT_TS */
        u_char  ipt_len;                /* size of structure (variable) */
        u_char  ipt_ptr;                /* index of current entry */
        u_char  ipt_flg:4,              /* flags, see below */
                ipt_oflw:4;             /* overflow counter */
        union {
                n_long  ipt_time[1];
                struct  ipt_ta {
                        struct socket ipt_addr;
                        n_long ipt_time;
                } ipt_ta[1];
        }
};

/* flag bits for ipt_flg */
#define IPOPT_TS_TSONLY         0               /* timestamps only */
#define IPOPT_TS_TSANDADDR      1               /* timestamps and addresses */
#define IPOPT_TS_PRESPEC        2               /* 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

/*
 * Ip reassembly queue structure.  Each fragment
 * being reassambled is attached to one of these structures.
 * They are timed out after ipq_ttl drops to 0, and may also
 * be reclaimed if memory becomes tight.
 */
struct ipq {
        struct  ipq *next,*prev;        /* to other reass headers */
        u_char  ipq_ttl;                /* time for reass q to live */
        u_char  ipq_p;                  /* protocol of this fragment */
        u_short ipq_id;                 /* sequence id for reassembly */
        struct  ip *ipq_next,*ipq_prev; /* to ip headers of fragments */
        struct  socket ipq_src,ipq_dst;
};

/*
 * Internet implementation parameters.
 */
#define MAXTTL          255             /* maximum time to live (seconds) */
#define IPFRAGTTL       15              /* time to live for frag chains */

#ifdef KERNEL
struct  ipq     ipq;                    /* ip reass. queue */
struct  ipq     *ip_freef();
u_short ip_id;                          /* ip packet ctr, for ids */
#endif