/*
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 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_icmp.h	8.1 (Berkeley) 6/10/93
 */

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

/*
 * 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 {
			n_short	icd_id;
			n_short	icd_seq;
		} ih_idseq;
		int ih_void;

		/* ICMP_UNREACH_NEEDFRAG -- Path MTU Discovery (RFC1191) */
		struct ih_pmtu {
			n_short ipm_void;    
			n_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;
		u_long	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)

#ifdef KERNEL
void	icmp_error __P((struct mbuf *, int, int, n_long, struct ifnet *));
void	icmp_input __P((struct mbuf *, int));
void	icmp_reflect __P((struct mbuf *));
void	icmp_send __P((struct mbuf *, struct mbuf *));
int	icmp_sysctl __P((int *, u_int, void *, size_t *, void *, size_t));
#endif
