ARK-OS/arkos/system/sysroot/usr/include/netinet/in.h

/* Copyright (C) 1991-2026 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#ifndef	_NETINET_IN_H
#define	_NETINET_IN_H	1

#include <features.h>
#include <bits/stdint-uintn.h>
#include <sys/socket.h>
#include <bits/types.h>


__BEGIN_DECLS

/* Internet address.  */
typedef uint32_t in_addr_t;
struct in_addr
  {
    in_addr_t s_addr;
  };

/* Get system-specific definitions.  */
#include <bits/in.h>

/* Standard well-defined IP protocols.  */
enum
  {
    IPPROTO_IP = 0,	   /* Dummy protocol for TCP.  */
#define IPPROTO_IP		IPPROTO_IP
    IPPROTO_ICMP = 1,	   /* Internet Control Message Protocol.  */
#define IPPROTO_ICMP		IPPROTO_ICMP
    IPPROTO_IGMP = 2,	   /* Internet Group Management Protocol. */
#define IPPROTO_IGMP		IPPROTO_IGMP
    IPPROTO_IPIP = 4,	   /* IPIP tunnels (older KA9Q tunnels use 94).  */
#define IPPROTO_IPIP		IPPROTO_IPIP
    IPPROTO_TCP = 6,	   /* Transmission Control Protocol.  */
#define IPPROTO_TCP		IPPROTO_TCP
    IPPROTO_EGP = 8,	   /* Exterior Gateway Protocol.  */
#define IPPROTO_EGP		IPPROTO_EGP
    IPPROTO_PUP = 12,	   /* PUP protocol.  */
#define IPPROTO_PUP		IPPROTO_PUP
    IPPROTO_UDP = 17,	   /* User Datagram Protocol.  */
#define IPPROTO_UDP		IPPROTO_UDP
    IPPROTO_IDP = 22,	   /* XNS IDP protocol.  */
#define IPPROTO_IDP		IPPROTO_IDP
    IPPROTO_TP = 29,	   /* SO Transport Protocol Class 4.  */
#define IPPROTO_TP		IPPROTO_TP
    IPPROTO_DCCP = 33,	   /* Datagram Congestion Control Protocol.  */
#define IPPROTO_DCCP		IPPROTO_DCCP
    IPPROTO_IPV6 = 41,     /* IPv6 header.  */
#define IPPROTO_IPV6		IPPROTO_IPV6
    IPPROTO_RSVP = 46,	   /* Reservation Protocol.  */
#define IPPROTO_RSVP		IPPROTO_RSVP
    IPPROTO_GRE = 47,	   /* General Routing Encapsulation.  */
#define IPPROTO_GRE		IPPROTO_GRE
    IPPROTO_ESP = 50,      /* encapsulating security payload.  */
#define IPPROTO_ESP		IPPROTO_ESP
    IPPROTO_AH = 51,       /* authentication header.  */
#define IPPROTO_AH		IPPROTO_AH
    IPPROTO_MTP = 92,	   /* Multicast Transport Protocol.  */
#define IPPROTO_MTP		IPPROTO_MTP
    IPPROTO_BEETPH = 94,   /* IP option pseudo header for BEET.  */
#define IPPROTO_BEETPH		IPPROTO_BEETPH
    IPPROTO_ENCAP = 98,	   /* Encapsulation Header.  */
#define IPPROTO_ENCAP		IPPROTO_ENCAP
    IPPROTO_PIM = 103,	   /* Protocol Independent Multicast.  */
#define IPPROTO_PIM		IPPROTO_PIM
    IPPROTO_COMP = 108,	   /* Compression Header Protocol.  */
#define IPPROTO_COMP		IPPROTO_COMP
    IPPROTO_L2TP = 115,	   /* Layer 2 Tunnelling Protocol.  */
#define IPPROTO_L2TP		IPPROTO_L2TP
    IPPROTO_SCTP = 132,	   /* Stream Control Transmission Protocol.  */
#define IPPROTO_SCTP		IPPROTO_SCTP
    IPPROTO_UDPLITE = 136, /* UDP-Lite protocol.  */
#define IPPROTO_UDPLITE		IPPROTO_UDPLITE
    IPPROTO_MPLS = 137,    /* MPLS in IP.  */
#define IPPROTO_MPLS		IPPROTO_MPLS
    IPPROTO_ETHERNET = 143, /* Ethernet-within-IPv6 Encapsulation.  */
#define IPPROTO_ETHERNET	IPPROTO_ETHERNET
    IPPROTO_RAW = 255,	   /* Raw IP packets.  */
#define IPPROTO_RAW		IPPROTO_RAW
    IPPROTO_SMC = 256,	   /* Shared Memory Communications.  */
#define IPPROTO_SMC		IPPROTO_SMC
    IPPROTO_MPTCP = 262,   /* Multipath TCP connection.  */
#define IPPROTO_MPTCP		IPPROTO_MPTCP
    IPPROTO_MAX
  };

/* If __USE_KERNEL_IPV6_DEFS is 1 then the user has included the kernel
   network headers first and we should use those ABI-identical definitions
   instead of our own, otherwise 0.  */
#if !__USE_KERNEL_IPV6_DEFS
enum
  {
    IPPROTO_HOPOPTS = 0,   /* IPv6 Hop-by-Hop options.  */
#define IPPROTO_HOPOPTS		IPPROTO_HOPOPTS
    IPPROTO_ROUTING = 43,  /* IPv6 routing header.  */
#define IPPROTO_ROUTING		IPPROTO_ROUTING
    IPPROTO_FRAGMENT = 44, /* IPv6 fragmentation header.  */
#define IPPROTO_FRAGMENT	IPPROTO_FRAGMENT
    IPPROTO_ICMPV6 = 58,   /* ICMPv6.  */
#define IPPROTO_ICMPV6		IPPROTO_ICMPV6
    IPPROTO_NONE = 59,     /* IPv6 no next header.  */
#define IPPROTO_NONE		IPPROTO_NONE
    IPPROTO_DSTOPTS = 60,  /* IPv6 destination options.  */
#define IPPROTO_DSTOPTS		IPPROTO_DSTOPTS
    IPPROTO_MH = 135       /* IPv6 mobility header.  */
#define IPPROTO_MH		IPPROTO_MH
  };
#endif /* !__USE_KERNEL_IPV6_DEFS */

/* Type to represent a port.  */
typedef uint16_t in_port_t;

/* Standard well-known ports.  */
enum
  {
    IPPORT_ECHO = 7,		/* Echo service.  */
    IPPORT_DISCARD = 9,		/* Discard transmissions service.  */
    IPPORT_SYSTAT = 11,		/* System status service.  */
    IPPORT_DAYTIME = 13,	/* Time of day service.  */
    IPPORT_NETSTAT = 15,	/* Network status service.  */
    IPPORT_FTP = 21,		/* File Transfer Protocol.  */
    IPPORT_TELNET = 23,		/* Telnet protocol.  */
    IPPORT_SMTP = 25,		/* Simple Mail Transfer Protocol.  */
    IPPORT_TIMESERVER = 37,	/* Timeserver service.  */
    IPPORT_NAMESERVER = 42,	/* Domain Name Service.  */
    IPPORT_WHOIS = 43,		/* Internet Whois service.  */
    IPPORT_MTP = 57,

    IPPORT_TFTP = 69,		/* Trivial File Transfer Protocol.  */
    IPPORT_RJE = 77,
    IPPORT_FINGER = 79,		/* Finger service.  */
    IPPORT_TTYLINK = 87,
    IPPORT_SUPDUP = 95,		/* SUPDUP protocol.  */


    IPPORT_EXECSERVER = 512,	/* execd service.  */
    IPPORT_LOGINSERVER = 513,	/* rlogind service.  */
    IPPORT_CMDSERVER = 514,
    IPPORT_EFSSERVER = 520,

    /* UDP ports.  */
    IPPORT_BIFFUDP = 512,
    IPPORT_WHOSERVER = 513,
    IPPORT_ROUTESERVER = 520,

    /* Ports less than this value are reserved for privileged processes.  */
    IPPORT_RESERVED = 1024,

    /* Ports greater this value are reserved for (non-privileged) servers.  */
    IPPORT_USERRESERVED = 5000
  };

/* Definitions of the bits in an Internet address integer.

   On subnets, host and network parts are found according to
   the subnet mask, not these masks.  */

#define	IN_CLASSA(a)		((((in_addr_t)(a)) & 0x80000000) == 0)
#define	IN_CLASSA_NET		0xff000000
#define	IN_CLASSA_NSHIFT	24
#define	IN_CLASSA_HOST		(0xffffffff & ~IN_CLASSA_NET)
#define	IN_CLASSA_MAX		128

#define	IN_CLASSB(a)		((((in_addr_t)(a)) & 0xc0000000) == 0x80000000)
#define	IN_CLASSB_NET		0xffff0000
#define	IN_CLASSB_NSHIFT	16
#define	IN_CLASSB_HOST		(0xffffffff & ~IN_CLASSB_NET)
#define	IN_CLASSB_MAX		65536

#define	IN_CLASSC(a)		((((in_addr_t)(a)) & 0xe0000000) == 0xc0000000)
#define	IN_CLASSC_NET		0xffffff00
#define	IN_CLASSC_NSHIFT	8
#define	IN_CLASSC_HOST		(0xffffffff & ~IN_CLASSC_NET)

#define	IN_CLASSD(a)		((((in_addr_t)(a)) & 0xf0000000) == 0xe0000000)
#define	IN_MULTICAST(a)		IN_CLASSD(a)

#define	IN_EXPERIMENTAL(a)	((((in_addr_t)(a)) & 0xe0000000) == 0xe0000000)
#define	IN_BADCLASS(a)		((((in_addr_t)(a)) & 0xf0000000) == 0xf0000000)

/* Address to accept any incoming messages.  */
#define	INADDR_ANY		((in_addr_t) 0x00000000)
/* Address to send to all hosts.  */
#define	INADDR_BROADCAST	((in_addr_t) 0xffffffff)
/* Address indicating an error return.  */
#define	INADDR_NONE		((in_addr_t) 0xffffffff)
/* Dummy address for source of ICMPv6 errors converted to IPv4 (RFC
   7600).  */
#define	INADDR_DUMMY		((in_addr_t) 0xc0000008)

/* Network number for local host loopback.  */
#define	IN_LOOPBACKNET		127
/* Address to loopback in software to local host.  */
#ifndef INADDR_LOOPBACK
# define INADDR_LOOPBACK	((in_addr_t) 0x7f000001) /* Inet 127.0.0.1.  */
#endif

/* Defines for Multicast INADDR.  */
#define INADDR_UNSPEC_GROUP	((in_addr_t) 0xe0000000) /* 224.0.0.0 */
#define INADDR_ALLHOSTS_GROUP	((in_addr_t) 0xe0000001) /* 224.0.0.1 */
#define INADDR_ALLRTRS_GROUP    ((in_addr_t) 0xe0000002) /* 224.0.0.2 */
#define INADDR_ALLSNOOPERS_GROUP ((in_addr_t) 0xe000006a) /* 224.0.0.106 */
#define INADDR_MAX_LOCAL_GROUP  ((in_addr_t) 0xe00000ff) /* 224.0.0.255 */

#if !__USE_KERNEL_IPV6_DEFS
/* IPv6 address */
struct in6_addr
  {
    union
      {
	uint8_t	__u6_addr8[16];
	uint16_t __u6_addr16[8];
	uint32_t __u6_addr32[4];
      } __in6_u;
#define s6_addr			__in6_u.__u6_addr8
#ifdef __USE_MISC
# define s6_addr16		__in6_u.__u6_addr16
# define s6_addr32		__in6_u.__u6_addr32
#endif
  };
#endif /* !__USE_KERNEL_IPV6_DEFS */

extern const struct in6_addr in6addr_any;        /* :: */
extern const struct in6_addr in6addr_loopback;   /* ::1 */
#define IN6ADDR_ANY_INIT { { { 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 } } }
#define IN6ADDR_LOOPBACK_INIT { { { 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1 } } }

#define INET_ADDRSTRLEN 16
#define INET6_ADDRSTRLEN 46


/* Structure describing an Internet socket address.  */
struct __attribute_struct_may_alias__ sockaddr_in
  {
    __SOCKADDR_COMMON (sin_);
    in_port_t sin_port;			/* Port number.  */
    struct in_addr sin_addr;		/* Internet address.  */

    /* Pad to size of `struct sockaddr'.  */
    unsigned char sin_zero[sizeof (struct sockaddr)
			   - __SOCKADDR_COMMON_SIZE
			   - sizeof (in_port_t)
			   - sizeof (struct in_addr)];
  };

#if __USE_KERNEL_IPV6_DEFS
struct __attribute_struct_may_alias__ sockaddr_in6;
#else
/* Ditto, for IPv6.  */
struct __attribute_struct_may_alias__ sockaddr_in6
  {
    __SOCKADDR_COMMON (sin6_);
    in_port_t sin6_port;	/* Transport layer port # */
    uint32_t sin6_flowinfo;	/* IPv6 flow information */
    struct in6_addr sin6_addr;	/* IPv6 address */
    uint32_t sin6_scope_id;	/* IPv6 scope-id */
  };
#endif /* !__USE_KERNEL_IPV6_DEFS */

#ifdef __USE_MISC
/* IPv4 multicast request.  */
struct ip_mreq
  {
    /* IP multicast address of group.  */
    struct in_addr imr_multiaddr;

    /* Local IP address of interface.  */
    struct in_addr imr_interface;
  };

/* IPv4 multicast request with interface index.  */
struct ip_mreqn
  {
    /* IP multicast address of group.  */
    struct in_addr imr_multiaddr;

    /* Local IP address of interface.  */
    struct in_addr imr_address;

    /* Interface index.  */
    int imr_ifindex;
  };

struct ip_mreq_source
  {
    /* IP multicast address of group.  */
    struct in_addr imr_multiaddr;

    /* IP address of interface.  */
    struct in_addr imr_interface;

    /* IP address of source.  */
    struct in_addr imr_sourceaddr;
  };
#endif

#if !__USE_KERNEL_IPV6_DEFS
/* Likewise, for IPv6.  */
struct ipv6_mreq
  {
    /* IPv6 multicast address of group */
    struct in6_addr ipv6mr_multiaddr;

    /* local interface */
    unsigned int ipv6mr_interface;
  };
#endif /* !__USE_KERNEL_IPV6_DEFS */

#ifdef __USE_MISC
/* Multicast group request.  */
struct group_req
  {
    /* Interface index.  */
    uint32_t gr_interface;

    /* Group address.  */
    struct sockaddr_storage gr_group;
  };

struct group_source_req
  {
    /* Interface index.  */
    uint32_t gsr_interface;

    /* Group address.  */
    struct sockaddr_storage gsr_group;

    /* Source address.  */
    struct sockaddr_storage gsr_source;
  };


/* Full-state filter operations.  */
struct ip_msfilter
  {
    /* IP multicast address of group.  */
    struct in_addr imsf_multiaddr;

    /* Local IP address of interface.  */
    struct in_addr imsf_interface;

    /* Filter mode.  */
    uint32_t imsf_fmode;

    /* Number of source addresses.  */
    uint32_t imsf_numsrc;
    /* Source addresses.  */
    struct in_addr imsf_slist[1];
  };

#define IP_MSFILTER_SIZE(numsrc) (sizeof (struct ip_msfilter) \
				  - sizeof (struct in_addr)		      \
				  + (numsrc) * sizeof (struct in_addr))

struct group_filter
  {
    /* Interface index.  */
    uint32_t gf_interface;

    /* Group address.  */
    struct sockaddr_storage gf_group;

    /* Filter mode.  */
    uint32_t gf_fmode;

    /* Number of source addresses.  */
    uint32_t gf_numsrc;
    /* Source addresses.  */
    struct sockaddr_storage gf_slist[1];
};

#define GROUP_FILTER_SIZE(numsrc) (sizeof (struct group_filter) \
				   - sizeof (struct sockaddr_storage)	      \
				   + ((numsrc)				      \
				      * sizeof (struct sockaddr_storage)))
#endif

/* Functions to convert between host and network byte order.

   Please note that these functions normally take `unsigned long int' or
   `unsigned short int' values as arguments and also return them.  But
   this was a short-sighted decision since on different systems the types
   may have different representations but the values are always the same.  */

extern uint32_t ntohl (uint32_t __netlong) __THROW __attribute__ ((__const__));
extern uint16_t ntohs (uint16_t __netshort)
     __THROW __attribute__ ((__const__));
extern uint32_t htonl (uint32_t __hostlong)
     __THROW __attribute__ ((__const__));
extern uint16_t htons (uint16_t __hostshort)
     __THROW __attribute__ ((__const__));

#include <endian.h>

/* Get machine dependent optimized versions of byte swapping functions.  */
#include <bits/byteswap.h>
#include <bits/uintn-identity.h>

#ifdef __OPTIMIZE__
/* We can optimize calls to the conversion functions.  Either nothing has
   to be done or we are using directly the byte-swapping functions which
   often can be inlined.  */
# if __BYTE_ORDER == __BIG_ENDIAN
/* The host byte order is the same as network byte order,
   so these functions are all just identity.  */
# define ntohl(x)	__uint32_identity (x)
# define ntohs(x)	__uint16_identity (x)
# define htonl(x)	__uint32_identity (x)
# define htons(x)	__uint16_identity (x)
# else
#  if __BYTE_ORDER == __LITTLE_ENDIAN
#   define ntohl(x)	__bswap_32 (x)
#   define ntohs(x)	__bswap_16 (x)
#   define htonl(x)	__bswap_32 (x)
#   define htons(x)	__bswap_16 (x)
#  endif
# endif
#endif

#ifdef __GNUC__
# define IN6_IS_ADDR_UNSPECIFIED(a) \
  (__extension__							      \
   ({ const struct in6_addr *__a = (const struct in6_addr *) (a);	      \
      __a->__in6_u.__u6_addr32[0] == 0					      \
      && __a->__in6_u.__u6_addr32[1] == 0				      \
      && __a->__in6_u.__u6_addr32[2] == 0				      \
      && __a->__in6_u.__u6_addr32[3] == 0; }))

# define IN6_IS_ADDR_LOOPBACK(a) \
  (__extension__							      \
   ({ const struct in6_addr *__a = (const struct in6_addr *) (a);	      \
      __a->__in6_u.__u6_addr32[0] == 0					      \
      && __a->__in6_u.__u6_addr32[1] == 0				      \
      && __a->__in6_u.__u6_addr32[2] == 0				      \
      && __a->__in6_u.__u6_addr32[3] == htonl (1); }))

# define IN6_IS_ADDR_LINKLOCAL(a) \
  (__extension__							      \
   ({ const struct in6_addr *__a = (const struct in6_addr *) (a);	      \
      (__a->__in6_u.__u6_addr32[0] & htonl (0xffc00000)) == htonl (0xfe800000); }))

# define IN6_IS_ADDR_SITELOCAL(a) \
  (__extension__							      \
   ({ const struct in6_addr *__a = (const struct in6_addr *) (a);	      \
      (__a->__in6_u.__u6_addr32[0] & htonl (0xffc00000)) == htonl (0xfec00000); }))

# define IN6_IS_ADDR_V4MAPPED(a) \
  (__extension__							      \
   ({ const struct in6_addr *__a = (const struct in6_addr *) (a);	      \
      __a->__in6_u.__u6_addr32[0] == 0					      \
      && __a->__in6_u.__u6_addr32[1] == 0				      \
      && __a->__in6_u.__u6_addr32[2] == htonl (0xffff); }))

# define IN6_IS_ADDR_V4COMPAT(a) \
  (__extension__							      \
   ({ const struct in6_addr *__a = (const struct in6_addr *) (a);	      \
      __a->__in6_u.__u6_addr32[0] == 0					      \
      && __a->__in6_u.__u6_addr32[1] == 0				      \
      && __a->__in6_u.__u6_addr32[2] == 0				      \
      && ntohl (__a->__in6_u.__u6_addr32[3]) > 1; }))

# define IN6_ARE_ADDR_EQUAL(a,b) \
  (__extension__							      \
   ({ const struct in6_addr *__a = (const struct in6_addr *) (a);	      \
      const struct in6_addr *__b = (const struct in6_addr *) (b);	      \
      __a->__in6_u.__u6_addr32[0] == __b->__in6_u.__u6_addr32[0]	      \
      && __a->__in6_u.__u6_addr32[1] == __b->__in6_u.__u6_addr32[1]	      \
      && __a->__in6_u.__u6_addr32[2] == __b->__in6_u.__u6_addr32[2]	      \
      && __a->__in6_u.__u6_addr32[3] == __b->__in6_u.__u6_addr32[3]; }))
#else
# define IN6_IS_ADDR_UNSPECIFIED(a) \
	(((const uint32_t *) (a))[0] == 0				      \
	 && ((const uint32_t *) (a))[1] == 0				      \
	 && ((const uint32_t *) (a))[2] == 0				      \
	 && ((const uint32_t *) (a))[3] == 0)

# define IN6_IS_ADDR_LOOPBACK(a) \
	(((const uint32_t *) (a))[0] == 0				      \
	 && ((const uint32_t *) (a))[1] == 0				      \
	 && ((const uint32_t *) (a))[2] == 0				      \
	 && ((const uint32_t *) (a))[3] == htonl (1))

# define IN6_IS_ADDR_LINKLOCAL(a) \
	((((const uint32_t *) (a))[0] & htonl (0xffc00000))		      \
	 == htonl (0xfe800000))

# define IN6_IS_ADDR_SITELOCAL(a) \
	((((const uint32_t *) (a))[0] & htonl (0xffc00000))		      \
	 == htonl (0xfec00000))

# define IN6_IS_ADDR_V4MAPPED(a) \
	((((const uint32_t *) (a))[0] == 0)				      \
	 && (((const uint32_t *) (a))[1] == 0)				      \
	 && (((const uint32_t *) (a))[2] == htonl (0xffff)))

# define IN6_IS_ADDR_V4COMPAT(a) \
	((((const uint32_t *) (a))[0] == 0)				      \
	 && (((const uint32_t *) (a))[1] == 0)				      \
	 && (((const uint32_t *) (a))[2] == 0)				      \
	 && (ntohl (((const uint32_t *) (a))[3]) > 1))

# define IN6_ARE_ADDR_EQUAL(a,b) \
	((((const uint32_t *) (a))[0] == ((const uint32_t *) (b))[0])	      \
	 && (((const uint32_t *) (a))[1] == ((const uint32_t *) (b))[1])      \
	 && (((const uint32_t *) (a))[2] == ((const uint32_t *) (b))[2])      \
	 && (((const uint32_t *) (a))[3] == ((const uint32_t *) (b))[3]))
#endif

#define IN6_IS_ADDR_MULTICAST(a) (((const uint8_t *) (a))[0] == 0xff)

#ifdef __USE_MISC
/* Bind socket to a privileged IP port.  */
extern int bindresvport (int __sockfd, struct sockaddr_in *__sock_in) __THROW;

/* The IPv6 version of this function.  */
extern int bindresvport6 (int __sockfd, struct sockaddr_in6 *__sock_in)
     __THROW;
#endif


#define IN6_IS_ADDR_MC_NODELOCAL(a) \
	(IN6_IS_ADDR_MULTICAST(a)					      \
	 && ((((const uint8_t *) (a))[1] & 0xf) == 0x1))

#define IN6_IS_ADDR_MC_LINKLOCAL(a) \
	(IN6_IS_ADDR_MULTICAST(a)					      \
	 && ((((const uint8_t *) (a))[1] & 0xf) == 0x2))

#define IN6_IS_ADDR_MC_SITELOCAL(a) \
	(IN6_IS_ADDR_MULTICAST(a)					      \
	 && ((((const uint8_t *) (a))[1] & 0xf) == 0x5))

#define IN6_IS_ADDR_MC_ORGLOCAL(a) \
	(IN6_IS_ADDR_MULTICAST(a)					      \
	 && ((((const uint8_t *) (a))[1] & 0xf) == 0x8))

#define IN6_IS_ADDR_MC_GLOBAL(a) \
	(IN6_IS_ADDR_MULTICAST(a)					      \
	 && ((((const uint8_t *) (a))[1] & 0xf) == 0xe))


#ifdef __USE_GNU
struct cmsghdr;			/* Forward declaration.  */

#if !__USE_KERNEL_IPV6_DEFS
/* IPv6 packet information.  */
struct in6_pktinfo
  {
    struct in6_addr ipi6_addr;	/* src/dst IPv6 address */
    unsigned int ipi6_ifindex;	/* send/recv interface index */
  };

/* IPv6 MTU information.  */
struct ip6_mtuinfo
  {
    struct sockaddr_in6 ip6m_addr; /* dst address including zone ID */
    uint32_t ip6m_mtu;		   /* path MTU in host byte order */
  };
#endif /* !__USE_KERNEL_IPV6_DEFS */

/* Obsolete hop-by-hop and Destination Options Processing (RFC 2292).  */
extern int inet6_option_space (int __nbytes)
     __THROW __attribute_deprecated__;
extern int inet6_option_init (void *__bp, struct cmsghdr **__cmsgp,
			      int __type) __THROW __attribute_deprecated__;
extern int inet6_option_append (struct cmsghdr *__cmsg,
				const uint8_t *__typep, int __multx,
				int __plusy) __THROW __attribute_deprecated__;
extern uint8_t *inet6_option_alloc (struct cmsghdr *__cmsg, int __datalen,
				    int __multx, int __plusy)
     __THROW __attribute_deprecated__;
extern int inet6_option_next (const struct cmsghdr *__cmsg,
			      uint8_t **__tptrp)
     __THROW __attribute_deprecated__;
extern int inet6_option_find (const struct cmsghdr *__cmsg,
			      uint8_t **__tptrp, int __type)
     __THROW __attribute_deprecated__;


/* Hop-by-Hop and Destination Options Processing (RFC 3542).  */
extern int inet6_opt_init (void *__extbuf, socklen_t __extlen) __THROW;
extern int inet6_opt_append (void *__extbuf, socklen_t __extlen, int __offset,
			     uint8_t __type, socklen_t __len, uint8_t __align,
			     void **__databufp) __THROW;
extern int inet6_opt_finish (void *__extbuf, socklen_t __extlen, int __offset)
     __THROW;
extern int inet6_opt_set_val (void *__databuf, int __offset, void *__val,
			      socklen_t __vallen) __THROW;
extern int inet6_opt_next (void *__extbuf, socklen_t __extlen, int __offset,
			   uint8_t *__typep, socklen_t *__lenp,
			   void **__databufp) __THROW;
extern int inet6_opt_find (void *__extbuf, socklen_t __extlen, int __offset,
			   uint8_t __type, socklen_t *__lenp,
			   void **__databufp) __THROW;
extern int inet6_opt_get_val (void *__databuf, int __offset, void *__val,
			      socklen_t __vallen) __THROW;


/* Routing Header Option (RFC 3542).  */
extern socklen_t inet6_rth_space (int __type, int __segments) __THROW;
extern void *inet6_rth_init (void *__bp, socklen_t __bp_len, int __type,
			     int __segments) __THROW;
extern int inet6_rth_add (void *__bp, const struct in6_addr *__addr) __THROW;
extern int inet6_rth_reverse (const void *__in, void *__out) __THROW;
extern int inet6_rth_segments (const void *__bp) __THROW;
extern struct in6_addr *inet6_rth_getaddr (const void *__bp, int __index)
     __THROW;


/* Multicast source filter support.  */

/* Get IPv4 source filter.  */
extern int getipv4sourcefilter (int __s, struct in_addr __interface_addr,
				struct in_addr __group, uint32_t *__fmode,
				uint32_t *__numsrc, struct in_addr *__slist)
     __THROW;

/* Set IPv4 source filter.  */
extern int setipv4sourcefilter (int __s, struct in_addr __interface_addr,
				struct in_addr __group, uint32_t __fmode,
				uint32_t __numsrc,
				const struct in_addr *__slist)
     __THROW;


/* Get source filter.  */
extern int getsourcefilter (int __s, uint32_t __interface_addr,
			    const struct sockaddr *__group,
			    socklen_t __grouplen, uint32_t *__fmode,
			    uint32_t *__numsrc,
			    struct sockaddr_storage *__slist) __THROW;

/* Set source filter.  */
extern int setsourcefilter (int __s, uint32_t __interface_addr,
			    const struct sockaddr *__group,
			    socklen_t __grouplen, uint32_t __fmode,
			    uint32_t __numsrc,
			    const struct sockaddr_storage *__slist) __THROW;
#endif	/* use GNU */

__END_DECLS

#endif	/* netinet/in.h */