/*
 * This file is part of the UCB release of Plan 9. It is subject to the license
 * terms in the LICENSE file found in the top-level directory of this
 * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No
 * part of the UCB release of Plan 9, including this file, may be copied,
 * modified, propagated, or distributed except according to the terms contained
 * in the LICENSE file.
 */

/* ICMP for IP v4 and v6 */
enum
{
	/* Packet Types, icmp v4 (rfc 792) */
	EchoReply	= 0,
	Unreachable	= 3,
	SrcQuench	= 4,
	Redirect	= 5,
	EchoRequest	= 8,
	TimeExceed	= 11,
	InParmProblem	= 12,
	Timestamp	= 13,
	TimestampReply	= 14,
	InfoRequest	= 15,
	InfoReply	= 16,
	AddrMaskRequest = 17,
	AddrMaskReply   = 18,
	Traceroute	= 30,
	IPv6WhereAreYou	= 33,
	IPv6IAmHere	= 34,

	/* packet types, icmp v6 (rfc 2463) */

        /* error messages */
	UnreachableV6	= 1,
	PacketTooBigV6	= 2,
	TimeExceedV6	= 3,
	ParamProblemV6	= 4,

        /* informational messages (rfc 2461 also) */
	EchoRequestV6	= 128,
	EchoReplyV6	= 129,
	RouterSolicit	= 133,
	RouterAdvert	= 134,
	NbrSolicit	= 135,
	NbrAdvert	= 136,
	RedirectV6	= 137,

	Maxtype6	= 137,

	ICMP_HDRSIZE	= 8,
};

typedef struct Ip4hdr Ip4hdr;
struct Ip4hdr
{
	unsigned char	vihl;		/* Version and header length */
	unsigned char	tos;		/* Type of service */
	unsigned char	length[2];	/* packet length */
	unsigned char	id[2];		/* Identification */
	unsigned char	frag[2];	/* Fragment information */
	unsigned char	ttl;		/* Time to live */
	unsigned char	proto;		/* Protocol */
	unsigned char	ipcksum[2];	/* Header checksum */
	unsigned char	src[4];		/* Ipv4 source */
	unsigned char	dst[4];		/* Ipv4 destination */

	unsigned char	data[];
};

// #define IP4HDRSZ offsetof(Ip4hdr, data[0])

/* the icmp payload has the same format in v4 and v6 */
typedef struct Icmphdr Icmphdr;
struct Icmphdr {
	unsigned char	type;
	unsigned char	code;
	unsigned char	cksum[2];
	unsigned char	icmpid[2];
	unsigned char	seq[2];
	unsigned char	data[];
};

// #define ICMPHDRSZ offsetof(Icmphdr, data[0])