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     /ˆائ„eوYkإأة ?÷     //* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 *	Linux INET6 implementation
 *
 *	Authors:
 *	Pedro Roque		<roque@di.fc.ul.pt>
 */

#ifndef _NET_IPV6_H
#define _NET_IPV6_H

#include <linux/ipv6.h>
#include <linux/hardirq.h>
#include <linux/jhash.h>
#include <linux/refcount.h>
#include <linux/jump_label_ratelimit.h>
#include <net/if_inet6.h>
#include <net/ndisc.h>
#include <net/flow.h>
#include <net/flow_dissector.h>
#include <net/inet_dscp.h>
#include <net/snmp.h>
#include <net/netns/hash.h>

struct ip_tunnel_info;

#define SIN6_LEN_RFC2133	24

#define IPV6_MAXPLEN		65535

/*
 *	NextHeader field of IPv6 header
 */

#define NEXTHDR_HOP		0	/* Hop-by-hop option header. */
#define NEXTHDR_IPV4		4	/* IPv4 in IPv6 */
#define NEXTHDR_TCP		6	/* TCP segment. */
#define NEXTHDR_UDP		17	/* UDP message. */
#define NEXTHDR_IPV6		41	/* IPv6 in IPv6 */
#define NEXTHDR_ROUTING		43	/* Routing header. */
#define NEXTHDR_FRAGMENT	44	/* Fragmentation/reassembly header. */
#define NEXTHDR_GRE		47	/* GRE header. */
#define NEXTHDR_ESP		50	/* Encapsulating security payload. */
#define NEXTHDR_AUTH		51	/* Authentication header. */
#define NEXTHDR_ICMP		58	/* ICMP for IPv6. */
#define NEXTHDR_NONE		59	/* No next header */
#define NEXTHDR_DEST		60	/* Destination options header. */
#define NEXTHDR_SCTP		132	/* SCTP message. */
#define NEXTHDR_MOBILITY	135	/* Mobility header. */

#define NEXTHDR_MAX		255

#define IPV6_DEFAULT_HOPLIMIT   64
#define IPV6_DEFAULT_MCASTHOPS	1

/* Limits on Hop-by-Hop and Destination options.
 *
 * Per RFC8200 there is no limit on the maximum number or lengths of options in
 * Hop-by-Hop or Destination options other then the packet must fit in an MTU.
 * We allow configurable limits in order to mitigate potential denial of
 * service attacks.
 *
 * There are three limits that may be set:
 *   - Limit the number of options in a Hop-by-Hop or Destination options
 *     extension header
 *   - Limit the byte length of a Hop-by-Hop or Destination options extension
 *     header
 *   - Disallow unknown options
 *
 * The limits are expressed in corresponding sysctls:
 *
 * ipv6.sysctl.max_dst_opts_cnt
 * ipv6.sysctl.max_hbh_opts_cnt
 * ipv6.sysctl.max_dst_opts_len
 * ipv6.sysctl.max_hbh_opts_len
 *
 * max_*_opts_cnt is the number of TLVs that are allowed for Destination
 * options or Hop-by-Hop options. If the number is less than zero then unknown
 * TLVs are disallowed and the number of known options that are allowed is the
 * absolute value. Setting the value to INT_MAX indicates no limit.
 *
 * max_*_opts_len is the length limit in bytes of a Destination or
 * Hop-by-Hop options extension header. Setting the value to INT_MAX
 * indicates no length limit.
 *
 * If a limit is exceeded when processing an extension header the packet is
 * silently discarded.
 */

/* Default limits for Hop-by-Hop and Destination options */
#define IP6_DEFAULT_MAX_DST_OPTS_CNT	 8
#define IP6_DEFAULT_MAX_HBH_OPTS_CNT	 8
#define IP6_DEFAULT_MAX_DST_OPTS_LEN	 INT_MAX /* No limit */
#define IP6_DEFAULT_MAX_HBH_OPTS_LEN	 INT_MAX /* No limit */

/*
 *	Addr type
 *	
 *	type	-	unicast | multicast
 *	scope	-	local	| site	    | global
 *	v4	-	compat
 *	v4mapped
 *	any
 *	loopback
 */

#define IPV6_ADDR_ANY		0x0000U

#define IPV6_ADDR_UNICAST	0x0001U
#define IPV6_ADDR_MULTICAST	0x0002U

#define IPV6_ADDR_LOOPBACK	0x0010U
#define IPV6_ADDR_LINKLOCAL	0x0020U
#define IPV6_ADDR_SITELOCAL	0x0040U

#define IPV6_ADDR_COMPATv4	0x0080U

#define IPV6_ADDR_SCOPE_MASK	0x00f0U

#define IPV6_ADDR_MAPPED	0x1000U

/*
 *	Addr scopes
 */
#define IPV6_ADDR_MC_SCOPE(a)	\
	((a)->s6_addr[1] & 0x0f)	/* nonstandard */
#define __IPV6_ADDR_SCOPE_INVALID	-1
#define IPV6_ADDR_SCOPE_NODELOCAL	0x01
#define IPV6_ADDR_SCOPE_LINKLOCAL	0x02
#define IPV6_ADDR_SCOPE_SITELOCAL	0x05
#define IPV6_ADDR_SCOPE_ORGLOCAL	0x08
#define IPV6_ADDR_SCOPE_GLOBAL		0x0e

/*
 *	Addr flags
 */
#define IPV6_ADDR_MC_FLAG_TRANSIENT(a)	\
	((a)->s6_addr[1] & 0x10)
#define IPV6_ADDR_MC_FLAG_PREFIX(a)	\
	((a)->s6_addr[1] & 0x20)
#define IPV6_ADDR_MC_FLAG_RENDEZVOUS(a)	\
	((a)->s