ip_icmp.h

/*
 * 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.
 * 3. 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_icmp.h	8.1 (Berkeley) 6/10/93
 * ip_icmp.h,v 1.4 1995/05/30 08:09:43 rgrimes Exp
 */

#ifndef _NETINET_IP_ICMP_H_
#define _NETINET_IP_ICMP_H_

/*
 * Interface Control Message Protocol Definitions.
 * Per RFC 792, September 1981.
 */

typedef u_int32_t n_time;

/*
 * Structure of an icmp header.
 */
struct icmp {
    u_char icmp_type; /* type of message, see below */
    u_char icmp_code; /* type sub code */
    u_short icmp_cksum; /* ones complement cksum of struct */
    union {
        u_char ih_pptr; /* ICMP_PARAMPROB */
        struct in_addr ih_gwaddr; /* ICMP_REDIRECT */
        struct ih_idseq {
            u_short icd_id;
            u_short icd_seq;
        } ih_idseq;
        int ih_void;

        /* ICMP_UNREACH_NEEDFRAG -- Path MTU Discovery (RFC1191) */
        struct ih_pmtu {
            u_short ipm_void;
            u_short ipm_nextmtu;
        } ih_pmtu;
    } icmp_hun;
#define icmp_pptr icmp_hun.ih_pptr
#define icmp_gwaddr icmp_hun.ih_gwaddr
#define icmp_id icmp_hun.ih_idseq.icd_id
#define icmp_seq icmp_hun.ih_idseq.icd_seq
#define icmp_void icmp_hun.ih_void
#define icmp_pmvoid icmp_hun.ih_pmtu.ipm_void
#define icmp_nextmtu icmp_hun.ih_pmtu.ipm_nextmtu
    union {
        struct id_ts {
            n_time its_otime;
            n_time its_rtime;
            n_time its_ttime;
        } id_ts;
        struct id_ip {
            struct ip idi_ip;
            /* options and then 64 bits of data */
        } id_ip;
        uint32_t id_mask;
        char id_data[1];
    } icmp_dun;
#define icmp_otime icmp_dun.id_ts.its_otime
#define icmp_rtime icmp_dun.id_ts.its_rtime
#define icmp_ttime icmp_dun.id_ts.its_ttime
#define icmp_ip icmp_dun.id_ip.idi_ip
#define icmp_mask icmp_dun.id_mask
#define icmp_data icmp_dun.id_data
};

/*
 * Lower bounds on packet lengths for various types.
 * For the error advice packets must first insure that the
 * packet is large enought to contain the returned ip header.
 * Only then can we do the check to see if 64 bits of packet
 * data have been returned, since we need to check the returned
 * ip header length.
 */
#define ICMP_MINLEN 8 /* abs minimum */
#define ICMP_TSLEN (8 + 3 * sizeof(n_time)) /* timestamp */
#define ICMP_MASKLEN 12 /* address mask */
#define ICMP_ADVLENMIN (8 + sizeof(struct ip) + 8) /* min */
#define ICMP_ADVLEN(p) (8 + ((p)->icmp_ip.ip_hl << 2) + 8)
/* N.B.: must separately check that ip_hl >= 5 */

/*
 * Definition of type and code field values.
 */
#define ICMP_ECHOREPLY 0 /* echo reply */
#define ICMP_UNREACH 3 /* dest unreachable, codes: */
#define ICMP_UNREACH_NET 0 /* bad net */
#define ICMP_UNREACH_HOST 1 /* bad host */
#define ICMP_UNREACH_PROTOCOL 2 /* bad protocol */
#define ICMP_UNREACH_PORT 3 /* bad port */
#define ICMP_UNREACH_NEEDFRAG 4 /* IP_DF caused drop */
#define ICMP_UNREACH_SRCFAIL 5 /* src route failed */
#define ICMP_UNREACH_NET_UNKNOWN 6 /* unknown net */
#define ICMP_UNREACH_HOST_UNKNOWN 7 /* unknown host */
#define ICMP_UNREACH_ISOLATED 8 /* src host isolated */
#define ICMP_UNREACH_NET_PROHIB 9 /* prohibited access */
#define ICMP_UNREACH_HOST_PROHIB 10 /* ditto */
#define ICMP_UNREACH_TOSNET 11 /* bad tos for net */
#define ICMP_UNREACH_TOSHOST 12 /* bad tos for host */
#define ICMP_SOURCEQUENCH 4 /* packet lost, slow down */
#define ICMP_REDIRECT 5 /* shorter route, codes: */
#define ICMP_REDIRECT_NET 0 /* for network */
#define ICMP_REDIRECT_HOST 1 /* for host */
#define ICMP_REDIRECT_TOSNET 2 /* for tos and net */
#define ICMP_REDIRECT_TOSHOST 3 /* for tos and host */
#define ICMP_ECHO 8 /* echo service */
#define ICMP_ROUTERADVERT 9 /* router advertisement */
#define ICMP_ROUTERSOLICIT 10 /* router solicitation */
#define ICMP_TIMXCEED 11 /* time exceeded, code: */
#define ICMP_TIMXCEED_INTRANS 0 /* ttl==0 in transit */
#define ICMP_TIMXCEED_REASS 1 /* ttl==0 in reass */
#define ICMP_PARAMPROB 12 /* ip header bad */
#define ICMP_PARAMPROB_OPTABSENT 1 /* req. opt. absent */
#define ICMP_TSTAMP 13 /* timestamp request */
#define ICMP_TSTAMPREPLY 14 /* timestamp reply */
#define ICMP_IREQ 15 /* information request */
#define ICMP_IREQREPLY 16 /* information reply */
#define ICMP_MASKREQ 17 /* address mask request */
#define ICMP_MASKREPLY 18 /* address mask reply */

#define ICMP_MAXTYPE 18

#define ICMP_INFOTYPE(type)                                         \
    ((type) == ICMP_ECHOREPLY || (type) == ICMP_ECHO ||             \
     (type) == ICMP_ROUTERADVERT || (type) == ICMP_ROUTERSOLICIT || \
     (type) == ICMP_TSTAMP || (type) == ICMP_TSTAMPREPLY ||         \
     (type) == ICMP_IREQ || (type) == ICMP_IREQREPLY ||             \
     (type) == ICMP_MASKREQ || (type) == ICMP_MASKREPLY)

void icmp_input _P((struct mbuf *, int));
void icmp_error(struct mbuf *msrc, u_char type, u_char code, int minsize,
                const char *message);
void icmp_reflect _P((struct mbuf *));

#endif