.\" $OpenBSD: inet6.4,v 1.32 2012/08/22 18:27:00 jmc Exp $ .\" $KAME: inet6.4,v 1.19 2000/11/24 10:13:18 itojun Exp $ .\" .\" Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. .\" 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. Neither the name of the project 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 PROJECT 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 PROJECT 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. .\" .Dd $Mdocdate: August 22 2012 $ .Dt INET6 4 .Os .Sh NAME .Nm inet6 .Nd Internet protocol version 6 family .Sh SYNOPSIS .Fd #include .Fd #include .Sh DESCRIPTION The .Nm family is an updated version of the .Xr inet 4 family. While .Xr inet 4 implements Internet Protocol version 4, .Nm implements Internet Protocol version 6. .Pp The .Nm family is comprised of the Internet Protocol version 6 .Pq Tn IPv6 network protocol, Internet Control Message Protocol version 6 .Pq Tn ICMPv6 , Transmission Control Protocol .Pq Tn TCP , and User Datagram Protocol .Pq Tn UDP . .Tn TCP is used to support the .Dv SOCK_STREAM abstraction while .Tn UDP is used to support the .Dv SOCK_DGRAM abstraction. Note that .Tn TCP and .Tn UDP are common to .Xr inet 4 and .Nm inet6 . A raw interface to .Tn IPv6 is available by creating an Internet socket of type .Dv SOCK_RAW . The .Tn ICMPv6 message protocol is accessible from a raw socket. .\" .Pp .\" The 128-bit IPv6 address contains both network and host parts. .\" However, direct examination of addresses is discouraged. .\" For those programs which absolutely need to break addresses .\" into their component parts, the following .\" .Xr ioctl 2 .\" commands are provided for a datagram socket in the .\" .Nm .\" domain; they have the same form as the .\" .Dv SIOCIFADDR .\" command (see .\" .Xr intro 4 ) . .\" .Pp .\" .Bl -tag -width SIOCSIFNETMASK .\" .It Dv SIOCSIFNETMASK .\" Set interface network mask. .\" The network mask defines the network part of the address; .\" if it contains more of the address than the address type would indicate, .\" then subnets are in use. .\" .It Dv SIOCGIFNETMASK .\" Get interface network mask. .\" .El .Pp For security reasons, .Ox does not route IPv4 traffic to an .Dv AF_INET6 socket, and does not support IPv4 mapped addresses, where IPv4 traffic is seen as if it comes from an IPv6 address like .Li ::ffff:10.1.1.1 . Where both IPv4 and IPv6 traffic need to be accepted, listen on two sockets. .Sh ADDRESSING IPv6 addresses are 16 byte quantities, stored in network standard byteorder. The include file .Aq Pa netinet/in.h defines this address as a discriminated union. .Pp Sockets bound to the .Nm family utilize the following addressing structure: .Bd -literal -offset indent struct sockaddr_in6 { u_int8_t sin6_len; sa_family_t sin6_family; in_port_t sin6_port; u_int32_t sin6_flowinfo; struct in6_addr sin6_addr; u_int32_t sin6_scope_id; }; .Ed .Pp Sockets may be created with the local address .Dq Dv :: .Po which is equal to IPv6 address .Dv 0:0:0:0:0:0:0:0 .Pc to effect .Dq wildcard matching on incoming messages. .Pp The IPv6 specification defines scoped address, like link-local or site-local address. A scoped address is ambiguous to the kernel, if it is specified without a scope identifier. To manipulate scoped addresses properly from userland, programs must use the advanced API defined in RFC 3542. A compact description of the advanced API is available in .Xr ip6 4 . If scoped addresses are specified without explicit scope, the kernel may raise an error. Note that scoped addresses are not for daily use at this moment, both from a specification and an implementation point of view. .Pp KAME implementation supports extended numeric IPv6 address notation for link-local addresses, like .Dq Li fe80::1%de0 to specify .Do .Li fe80::1 on .Li de0 interface .Dc . The notation is supported by .Xr getaddrinfo 3 and .Xr getnameinfo 3 . Some normal userland programs, such as .Xr telnet 1 or .Xr ftp 1 , are able to use the notation. With special programs like .Xr ping6 8 , an outgoing interface can be specified with an extra command line option to disambiguate scoped addresses. .Pp Scoped addresses are handled specially in the kernel. In the kernel structures like routing tables or interface structure, scoped addresses will have their interface index embedded into the address. Therefore, the address on some of the kernel structure is not the same as that on the wire. The embedded index will become visible on .Dv PF_ROUTE socket, kernel memory accesses via .Xr kvm 3 and some other occasions. HOWEVER, users should never use the embedded form. For details please consult .Lk http://www.kame.net/dev/cvsweb2.cgi/kame/IMPLEMENTATION . Note that the above URL describes the situation with the latest KAME tree, not the .Ox tree. .Sh SEE ALSO .Xr ioctl 2 , .Xr socket 2 , .Xr sysctl 3 , .Xr icmp6 4 , .Xr intro 4 , .Xr ip6 4 , .Xr tcp 4 , .Xr udp 4 .Sh STANDARDS .Rs .%A Tatsuya Jinmei .%A Atsushi Onoe .%D June 2000 .%N draft-ietf-ipngwg-scopedaddr-format-02.txt .%O work in progress material .%R internet draft .%T "An Extension of Format for IPv6 Scoped Addresses" .Re .Pp .Rs .%A R. Gilligan .%A S. Thomson .%A J. Bound .%A J. McCann .%A W. Stevens .%D February 2003 .%R RFC 3493 .%T Basic Socket Interface Extensions for Ipv6 .Re .Pp .Rs .%A W. Stevens .%A M. Thomas .%A E. Nordmark .%A T. Jinmei .%D May 2003 .%R RFC 3542 .%T Advanced Sockets Application Programming Interface (API) for IPv6 .Re .Sh HISTORY The implementation described herein appeared in WIDE/KAME project. .Sh BUGS The IPv6 support is subject to change as the Internet protocols develop. Users should not depend on details of the current implementation, but rather the services exported. .Pp .Dq Version independent code should be implemented as much as possible in order to support both .Xr inet 4 and .Nm inet6 .