225 lines
6.9 KiB
Groff
225 lines
6.9 KiB
Groff
.\" $KAME: inet6_rth_space.3,v 1.7 2005/01/05 03:00:44 itojun Exp $
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.\"
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.\" Copyright (C) 2004 WIDE Project.
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the project nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd December 24, 2004
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.Dt INET6_RTH_SPACE 3
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.Os
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.\"
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.Sh NAME
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.Nm inet6_rth_space ,
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.Nm inet6_rth_init ,
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.Nm inet6_rth_add ,
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.Nm inet6_rth_reverse ,
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.Nm inet6_rth_segments ,
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.Nm inet6_rth_getaddr
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.Nd IPv6 Routing Header Options manipulation
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.\"
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.Sh SYNOPSIS
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.In netinet/in.h
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.Ft socklen_t
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.Fn inet6_rth_space "int" "int"
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.Ft "void *"
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.Fn inet6_rth_init "void *" "socklen_t" "int" "int"
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.Ft int
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.Fn inet6_rth_add "void *" "const struct in6_addr *"
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.Ft int
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.Fn inet6_rth_reverse "const void *" "void *"
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.Ft int
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.Fn inet6_rth_segments "const void *"
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.Ft "struct in6_addr *"
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.Fn inet6_rth_getaddr "const void *" "int"
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.\"
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.Sh DESCRIPTION
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The IPv6 Advanced API, RFC 3542, defines the functions that an
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application calls to build and examine IPv6 Routing headers.
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Routing headers are used to perform source routing in IPv6 networks.
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The RFC uses the word
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.Dq segments
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to describe addresses and that is the term used here as well.
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All of the functions are defined in the
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.In netinet/in.h
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header file.
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The functions described in this manual page all operate
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on routing header structures which are defined in
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.In netinet/ip6.h
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but which should not need to be modified outside the use of this API.
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The size and shape of the route header structures may change, so using
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the APIs is a more portable, long term, solution.
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.Pp
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The functions in the API are split into two groups, those that build a
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routing header and those that parse a received routing header.
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We will describe the builder functions followed by the parser functions.
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.Ss inet6_rth_space
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The
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.Fn inet6_rth_space
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function returns the number of bytes required to hold a Routing Header
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of the type, specified in the
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.Fa type
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argument and containing the number of addresses specified in the
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.Fa segments
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argumment.
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When the type is
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.Dv IPV6_RTHDR_TYPE_0
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the number of segments must be from 0 through 127.
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Routing headers of type
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.Dv IPV6_RTHDR_TYPE_2
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contain only one segment, and are only used with Mobile IPv6.
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The return value from this function is the number of bytes required to
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store the routing header.
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If the value 0 is returned then either the
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route header type was not recognized or another error occurred.
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.Ss inet6_rth_init
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The
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.Fn inet6_rth_init
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function initializes the pre-allocated buffer pointed to by
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.Fa bp
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to contain a routing header of the specified type The
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.Fa bp_len
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argument is used to verify that the buffer is large enough.
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The caller must allocate the buffer pointed to by bp.
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The necessary buffer size should be determined by calling
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.Fn inet6_rth_space
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described in the previous sections.
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.Pp
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The
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.Fn inet6_rth_init
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function returns a pointer to
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.Fa bp
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on success and
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.Dv NULL
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when there is an error.
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.Ss inet6_rth_add
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The
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.Fn inet6_rth_add
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function adds the IPv6 address pointed to by
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.Fa addr
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to the end of the routing header being constructed.
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.Pp
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A successful addition results in the function returning 0, otherwise
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\-1 is returned.
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.Ss inet6_rth_reverse
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The
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.Fn inet6_rth_reverse
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function takes a routing header, pointed to by the
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argument
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.Fa in ,
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and writes a new routing header into the argument pointed to by
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.Fa out .
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The routing header at that sends datagrams along the reverse of that
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route.
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Both arguments are allowed to point to the same buffer meaning
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that the reversal can occur in place.
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.Pp
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The return value of the function is 0 on success, or \-1 when
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there is an error.
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.\"
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.Pp
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The next set of functions operate on a routing header that the
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application wants to parse.
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In the usual case such a routing header
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is received from the network, although these functions can also be
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used with routing headers that the application itself created.
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.Ss inet6_rth_segments
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The
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.Fn inet6_rth_segments
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function returns the number of segments contained in the
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routing header pointed to by
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.Fa bp .
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The return value is the number of segments contained in the routing
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header, or \-1 if an error occurred.
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It is not an error for 0 to be
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returned as a routing header may contain 0 segments.
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.\"
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.Ss inet6_rth_getaddr
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The
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.Fn inet6_rth_getaddr
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function is used to retrieve a single address from a routing header.
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The
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.Fa index
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is the location in the routing header from which the application wants
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to retrieve an address.
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The
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.Fa index
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parameter must have a value between 0 and one less than the number of
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segments present in the routing header.
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The
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.Fn inet6_rth_segments
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function, described in the last section, should be used to determine
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the total number of segments in the routing header.
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The
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.Fn inet6_rth_getaddr
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function returns a pointer to an IPv6 address on success or
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.Dv NULL
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when an error has occurred.
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.\"
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.Sh DIAGNOSTICS
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The
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.Fn inet6_rth_space
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and
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.Fn inet6_rth_getaddr
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functions return 0 on errors.
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.Pp
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The
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.Fn inet6_rthdr_init
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function returns
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.Dv NULL
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on error.
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The
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.Fn inet6_rth_add
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and
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.Fn inet6_rth_reverse
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functions return 0 on success, or \-1 upon an error.
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.\"
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.Sh EXAMPLES
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RFC 3542 gives extensive examples in Section 21, Appendix B.
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.Pp
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KAME also provides examples in the advapitest directory of its kit.
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.\"
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.Sh SEE ALSO
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.Rs
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.%A W. Stevens
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.%A M. Thomas
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.%A E. Nordmark
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.%A T. Jinmei
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.%T "Advanced Sockets API for IPv6"
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.%N RFC 3542
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.%D May 2003
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.Re
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.Rs
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.%A S. Deering
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.%A R. Hinden
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.%T "Internet Protocol, Version 6 (IPv6) Specification"
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.%N RFC2460
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.%D December 1998
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.Re
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.Sh HISTORY
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The implementation first appeared in KAME advanced networking kit.
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