/*
 * Internet Protocol Version 6
 *
 * rfc2460 defines the protocol.
 * rfc4291 defines the address prefices.
 *
 * global unicast is anything but unspecified (::), loopback (::1),
 * multicast (ff00::/8), and link-local unicast (fe80::/10).
 *
 * site-local (fec0::/10) is now deprecated by rfc3879.
 *
 * Unique Local IPv6 Unicast Addresses are defined by rfc4193.
 * prefix is fc00::/7, scope is global, routing is limited to roughly a site.
 */
#define isv6mcast(addr)	  ((addr)[0] == 0xff)
#define islinklocal(addr) ((addr)[0] == 0xfe && ((addr)[1] & 0xc0) == 0x80)

#define optexsts(np)	(nhgets((np)->ploadlen) > 24)
#define issmcast(addr)	(memcmp((addr), v6solicitednode, 13) == 0)

#ifndef MIN
#define MIN(a, b) ((a) <= (b)? (a): (b))
#endif

enum {				/* Header Types */
	HBH		= 0,	/* hop-by-hop multicast routing protocol */
	ICMP		= 1,
	IGMP		= 2,
	GGP		= 3,
	IPINIP		= 4,
	ST		= 5,
	TCP		= 6,
	UDP		= 17,
	ISO_TP4		= 29,
	RH		= 43,
	FH		= 44,
	IDRP		= 45,
	RSVP		= 46,
	AH		= 51,
	ESP		= 52,
	ICMPv6		= 58,
	NNH		= 59,
	DOH		= 60,
	ISO_IP		= 80,
	IGRP		= 88,
	OSPF		= 89,

	Maxhdrtype	= 256,
};

enum {
	/* multicast flags and scopes */

//	Well_known_flg	= 0,
//	Transient_flg	= 1,

//	Interface_local_scop = 1,
	Link_local_scop	= 2,
//	Site_local_scop	= 5,
//	Org_local_scop	= 8,
	Global_scop	= 14,

	/* various prefix lengths */
	SOLN_PREF_LEN	= 13,

	/* icmpv6 unreach codes */
	icmp6_no_route		= 0,
	icmp6_ad_prohib		= 1,
	icmp6_unassigned	= 2,
	icmp6_adr_unreach	= 3,
	icmp6_port_unreach	= 4,
	icmp6_unkn_code		= 5,

	/* various flags & constants */
	v6MINTU		= 1280,
	HOP_LIMIT	= 255,
	ETHERHDR_LEN	= 14,
	IPV6HDR_LEN	= 40,
	IPV4HDR_LEN	= 20,

	/* option types */

	SRC_LLADDR	= 1,
	TARGET_LLADDR	= 2,
	PREFIX_INFO	= 3,
	REDIR_HEADER	= 4,
	MTU_OPTION	= 5,

	SRC_UNSPEC	= 0,
	SRC_UNI		= 1,
	TARG_UNI	= 2,
	TARG_MULTI	= 3,

	Tunitent	= 1,
	Tuniproxy	= 2,
	Tunirany	= 3,

	/* Router constants (all times in milliseconds) */
	MAX_INIT_RTR_ADVERT_INTVL = 16000,
	MAX_INIT_RTR_ADVERTS	= 3,
	MAX_FINAL_RTR_ADVERTS	= 3,
	MIN_DELAY_BETWEEN_RAS	= 3000,
	MAX_RA_DELAY_TIME	= 500,

	/* Host constants */
	MAX_RTR_SOLICIT_DELAY	= 1000,
	RTR_SOLICIT_INTVL	= 4000,
	MAX_RTR_SOLICITS	= 3,

	/* Node constants */
	MAX_MULTICAST_SOLICIT	= 3,
	MAX_UNICAST_SOLICIT	= 3,
	MAX_ANYCAST_DELAY_TIME	= 1000,
	MAX_NEIGHBOR_ADVERT	= 3,
	REACHABLE_TIME		= 30000,
	RETRANS_TIMER		= 1000,
	DELAY_FIRST_PROBE_TIME	= 5000,
};

typedef struct Ip6hdr	Ip6hdr;
typedef struct Opthdr	Opthdr;
typedef struct Routinghdr Routinghdr;
typedef struct Fraghdr6	Fraghdr6;

struct	Ip6hdr {
	uchar	vcf[4];		/* version:4, traffic class:8, flow label:20 */
	uchar	ploadlen[2];	/* payload length: packet length - 40 */
	uchar	proto;		/* next header type */
	uchar	ttl;		/* hop limit */
	uchar	src[IPaddrlen];
	uchar	dst[IPaddrlen];
};

struct	Opthdr {
	uchar	nexthdr;
	uchar	len;
};

struct	Routinghdr {
	uchar	nexthdr;
	uchar	len;
	uchar	rtetype;
	uchar	segrem;
};

struct	Fraghdr6 {
	uchar	nexthdr;
	uchar	res;
	uchar	offsetRM[2];	/* Offset, Res, M flag */
	uchar	id[4];
};

extern uchar v6allnodesN[IPaddrlen];
extern uchar v6allnodesL[IPaddrlen];
extern uchar v6allroutersN[IPaddrlen];
extern uchar v6allroutersL[IPaddrlen];
extern uchar v6allnodesNmask[IPaddrlen];
extern uchar v6allnodesLmask[IPaddrlen];
extern uchar v6allroutersS[IPaddrlen];
extern uchar v6solicitednode[IPaddrlen];
extern uchar v6solicitednodemask[IPaddrlen];
extern uchar v6Unspecified[IPaddrlen];
extern uchar v6loopback[IPaddrlen];
extern uchar v6loopbackmask[IPaddrlen];
extern uchar v6linklocal[IPaddrlen];
extern uchar v6linklocalmask[IPaddrlen];
extern uchar v6glunicast[IPaddrlen];
extern uchar v6multicast[IPaddrlen];
extern uchar v6multicastmask[IPaddrlen];

extern int v6llpreflen;
extern int v6lbpreflen;
extern int v6mcpreflen;
extern int v6snpreflen;
extern int v6aNpreflen;
extern int v6aLpreflen;

extern int ReTransTimer;

void ipv62smcast(uchar *, uchar *);
void icmpns(Fs *f, uchar* src, int suni, uchar* targ, int tuni, uchar* mac);
void icmpna(Fs *f, uchar* src, uchar* dst, uchar* targ, uchar* mac, uchar flags);
void icmpttlexceeded6(Fs *f, Ipifc *ifc, Block *bp);
void icmppkttoobig6(Fs *f, Ipifc *ifc, Block *bp);
void icmphostunr(Fs *f, Ipifc *ifc, Block *bp, int code, int free);