ip.h

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/*
 * Copyright (c) 1982, 1986, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      @(#)ip.h        8.2 (Berkeley) 6/1/94
 * $FreeBSD: src/sys/netinet/ip.h,v 1.29 2005/01/07 01:45:44 imp Exp $
 */


#ifndef _NETINET_IP_H_
#define _NETINET_IP_H_

#include <sys/cdefs.h>
#include <netinet/in.h> /* struct in_addr */
#include <netinet/in_systm.h> /* n_long */

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

#ifndef __packed
#if defined(__GNUC__)
#define __packed __attribute__((packed))
#define __aligned(x) __attribute__((aligned(x)))
#else
#define __packed
#define __aligned(x)
#endif
#endif

/*
 * Structure of an internet header, naked of options.
 */
struct ip {
#ifdef _IP_VHL
        u_char  ip_vhl;                 /* version << 4 | header length >> 2 */
#else
#if BYTE_ORDER == LITTLE_ENDIAN
        u_int   ip_hl:4,                /* header length */
                ip_v:4;                 /* version */
#endif
#if BYTE_ORDER == BIG_ENDIAN
        u_int   ip_v:4,                 /* version */
                ip_hl:4;                /* header length */
#endif
#endif /* not _IP_VHL */
        u_char  ip_tos;                 /* type of service */
        u_short ip_len;                 /* total length */
        u_short ip_id;                  /* identification */
        u_short ip_off;                 /* fragment offset field */
#define IP_RF 0x8000                    /* reserved fragment flag */
#define IP_DF 0x4000                    /* dont fragment flag */
#define IP_MF 0x2000                    /* more fragments flag */
#define IP_OFFMASK 0x1fff               /* mask for fragmenting bits */
        u_char  ip_ttl;                 /* time to live */
        u_char  ip_p;                   /* protocol */
        u_short ip_sum;                 /* checksum */
        struct  in_addr ip_src,ip_dst;  /* source and dest address */
} __packed __aligned(4);

#ifdef _IP_VHL
#define IP_MAKE_VHL(v, hl)      ((v) << 4 | (hl))
#define IP_VHL_HL(vhl)          ((vhl) & 0x0f)
#define IP_VHL_V(vhl)           ((vhl) >> 4)
#define IP_VHL_BORING           0x45
#endif

#ifdef CTASSERT
CTASSERT(sizeof (struct ip) == 20);
#endif

#define IP_MAXPACKET    65535L          /* maximum packet size */

/*
 * Definitions for IP type of service (ip_tos)
 */
#define IPTOS_LOWDELAY          0x10
#define IPTOS_THROUGHPUT        0x08
#define IPTOS_RELIABILITY       0x04
#define IPTOS_MINCOST           0x02
#if 1
/* ECN RFC3168 obsoletes RFC2481, and these will be deprecated soon. */
#define IPTOS_CE                0x01
#define IPTOS_ECT               0x02
#endif

/*
 * Definitions for IP precedence (also in ip_tos) (hopefully unused)
 */
#define IPTOS_PREC_NETCONTROL           0xe0
#define IPTOS_PREC_INTERNETCONTROL      0xc0
#define IPTOS_PREC_CRITIC_ECP           0xa0
#define IPTOS_PREC_FLASHOVERRIDE        0x80
#define IPTOS_PREC_FLASH                0x60
#define IPTOS_PREC_IMMEDIATE            0x40
#define IPTOS_PREC_PRIORITY             0x20
#define IPTOS_PREC_ROUTINE              0x00

/*
 * ECN (Explicit Congestion Notification) codepoints in RFC3168
 * mapped to the lower 2 bits of the TOS field.
 */
#define IPTOS_ECN_NOTECT        0x00    /* not-ECT */
#define IPTOS_ECN_ECT1          0x01    /* ECN-capable transport (1) */
#define IPTOS_ECN_ECT0          0x02    /* ECN-capable transport (0) */
#define IPTOS_ECN_CE            0x03    /* congestion experienced */
#define IPTOS_ECN_MASK          0x03    /* ECN field mask */

/*
 * 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_ESO               133             /* extended security */
#define IPOPT_CIPSO             134             /* commerical security */
#define IPOPT_SATID             136             /* satnet id */
#define IPOPT_SSRR              137             /* strict source route */
#define IPOPT_RA                148             /* router alert */

/*
 * 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 */

/*
 * 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 */
#if BYTE_ORDER == LITTLE_ENDIAN
        u_int   ipt_flg:4,              /* flags, see below */
                ipt_oflw:4;             /* overflow counter */
#endif
#if BYTE_ORDER == BIG_ENDIAN
        u_int   ipt_oflw:4,             /* overflow counter */
                ipt_flg:4;              /* flags, see below */
#endif
        union ipt_timestamp {
                n_long  ipt_time[1];
                struct  ipt_ta {
                        struct in_addr ipt_addr;
                        n_long ipt_time;
                } ipt_ta[1];
        } ipt_timestamp;
};

#include <machine/in_cksum.h>

/* 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

/*
 * Internet implementation parameters.
 */
#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 */

/*
 * This is the real IPv4 pseudo header, used for computing the TCP and UDP
 * checksums. For the Internet checksum, struct ipovly can be used instead.
 * For stronger checksums, the real thing must be used.
 */
struct ippseudo {
        struct  in_addr ippseudo_src;   /* source internet address */
        struct  in_addr ippseudo_dst;   /* destination internet address */
        u_char          ippseudo_pad;   /* pad, must be zero */
        u_char          ippseudo_p;     /* protocol */
        u_short         ippseudo_len;   /* protocol length */
};
#endif