add manpage for inet6_{option,rthdr}_*.

This commit is contained in:
itojun 1999-12-12 11:20:03 +00:00
parent 2e825f9c4e
commit a57d497906
4 changed files with 802 additions and 3 deletions

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@ -1,4 +1,4 @@
# $NetBSD: mi,v 1.172 1999/12/10 23:23:01 jlam Exp $ # $NetBSD: mi,v 1.173 1999/12/12 11:20:03 itojun Exp $
./sys ./sys
./usr/bin/ar ./usr/bin/ar
./usr/bin/as ./usr/bin/as
@ -3274,6 +3274,20 @@
./usr/share/man/man3/ilogbf.3 ./usr/share/man/man3/ilogbf.3
./usr/share/man/man3/index.3 ./usr/share/man/man3/index.3
./usr/share/man/man3/inet.3 ./usr/share/man/man3/inet.3
./usr/share/man/man3/inet6_option_alloc.3
./usr/share/man/man3/inet6_option_append.3
./usr/share/man/man3/inet6_option_find.3
./usr/share/man/man3/inet6_option_init.3
./usr/share/man/man3/inet6_option_next.3
./usr/share/man/man3/inet6_option_space.3
./usr/share/man/man3/inet6_rthdr_add.3
./usr/share/man/man3/inet6_rthdr_getaddr.3
./usr/share/man/man3/inet6_rthdr_getflags.3
./usr/share/man/man3/inet6_rthdr_init.3
./usr/share/man/man3/inet6_rthdr_lasthop.3
./usr/share/man/man3/inet6_rthdr_reverse.3
./usr/share/man/man3/inet6_rthdr_segments.3
./usr/share/man/man3/inet6_rthdr_space.3
./usr/share/man/man3/inet_addr.3 ./usr/share/man/man3/inet_addr.3
./usr/share/man/man3/inet_aton.3 ./usr/share/man/man3/inet_aton.3
./usr/share/man/man3/inet_lnaof.3 ./usr/share/man/man3/inet_lnaof.3

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@ -1,4 +1,4 @@
# $NetBSD: Makefile.inc,v 1.45 1999/11/10 22:41:00 jdolecek Exp $ # $NetBSD: Makefile.inc,v 1.46 1999/12/12 11:20:04 itojun Exp $
# @(#)Makefile.inc 8.2 (Berkeley) 9/5/93 # @(#)Makefile.inc 8.2 (Berkeley) 9/5/93
# net sources # net sources
@ -71,10 +71,23 @@ MLINKS+=resolver.3 dn_comp.3 resolver.3 dn_expand.3 resolver.3 res_init.3 \
resolver.3 res_search.3 resolver.3 res_search.3
# IPv6 # IPv6
MAN+= getaddrinfo.3 getnameinfo.3 if_indextoname.3 MAN+= getaddrinfo.3 getnameinfo.3 if_indextoname.3 \
inet6_option_space.3 inet6_rthdr_space.3
MLINKS+=getaddrinfo.3 freeaddrinfo.3 getaddrinfo.3 gai_strerror.3 \ MLINKS+=getaddrinfo.3 freeaddrinfo.3 getaddrinfo.3 gai_strerror.3 \
if_indextoname.3 if_nametoindex.3 if_indextoname.3 if_nameindex.3 \ if_indextoname.3 if_nametoindex.3 if_indextoname.3 if_nameindex.3 \
if_indextoname.3 if_freenameindex.3 \ if_indextoname.3 if_freenameindex.3 \
inet6_option_space.3 inet6_option_init.3 \
inet6_option_space.3 inet6_option_append.3 \
inet6_option_space.3 inet6_option_alloc.3 \
inet6_option_space.3 inet6_option_next.3 \
inet6_option_space.3 inet6_option_find.3 \
inet6_rthdr_space.3 inet6_rthdr_init.3 \
inet6_rthdr_space.3 inet6_rthdr_add.3 \
inet6_rthdr_space.3 inet6_rthdr_lasthop.3 \
inet6_rthdr_space.3 inet6_rthdr_reverse.3 \
inet6_rthdr_space.3 inet6_rthdr_segments.3 \
inet6_rthdr_space.3 inet6_rthdr_getaddr.3 \
inet6_rthdr_space.3 inet6_rthdr_getflags.3
# need to revisit # need to revisit
#MAN+= getipnodebyname.3 rresvport_af.3 #MAN+= getipnodebyname.3 rresvport_af.3
#MLINKS+=getipnodebyname.3 getipnodebyaddr.3 getipnodebyname.3 freehostent.3 \ #MLINKS+=getipnodebyname.3 getipnodebyaddr.3 getipnodebyname.3 freehostent.3 \

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@ -0,0 +1,451 @@
.\" $NetBSD: inet6_option_space.3,v 1.1 1999/12/12 11:20:04 itojun Exp $
.\"
.\" Copyright (c) 1983, 1987, 1991, 1993
.\" The Regents of the University of California. 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. All advertising materials mentioning features or use of this software
.\" must display the following acknowledgement:
.\" This product includes software developed by the University of
.\" California, Berkeley and its contributors.
.\" 4. Neither the name of the University 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 REGENTS 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 REGENTS 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.
.\"
.\" KAME Id: inet6_option_space.3,v 1.3 1999/12/10 07:01:02 itojun Exp
.\"
.Dd December 10, 1999
.Dt INET6_OPTION_SPACE 3
.Os
.\"
.Sh NAME
.Nm inet6_option_space ,
.Nm inet6_option_init ,
.Nm inet6_option_append ,
.Nm inet6_option_alloc ,
.Nm inet6_option_next ,
.Nm inet6_option_find
.Nd IPv6 Hop-by-Hop and Destination Options manipulation
.\"
.Sh SYNOPSIS
.Fd #include <netinet/in.h>
.Ft "int"
.Fn inet6_options_space "int nbytes"
.Ft "int"
.Fn inet6_option_init "void *bp" "struct cmsghdr **cmsgp" "int type"
.Ft "int"
.Fn inet6_option_append "struct cmsghdr *cmsg" "const u_int8_t *typep" "int multx" "int plusy"
.Ft "u_int8_t *"
.Fn inet6_option_alloc "struct cmsghdr *cmsg" "int datalen" "int multx" "int plusy";
.Ft "int"
.Fn inet6_option_next "const struct cmsghdr *cmsg" "u_int8_t **tptrp"
.Ft "int"
.Fn inet6_option_find "const struct cmsghdr *cmsg" "u_int8_t **tptrp" "int type"
.\"
.Sh DESCRIPTION
.\"
Building and parsing the Hop-by-Hop and Destination options is
complicated due to alignment constranints, padding and
ancillary data manipulation.
RFC2292 defines a set of functions to help the application.
The function prototypes for
these functions are all in the
.Aq Li netinet/in.h
header.
.\"
.Ss inet6_option_space
.Fn inet6_option_space
returns the number of bytes required to hold an option when it is stored as
ancillary data, including the
.Li cmsghdr
structure at the beginning,
and any padding at the end
.Po
to make its size a multiple of 8 bytes
.Pc .
The argument is the size of the structure defining the option,
which must include any pad bytes at the beginning
.Po
the value
.Li y
in the alignment term
.Dq Li xn + y
.Pc ,
the type byte, the length byte, and the option data.
.Pp
Note: If multiple options are stored in a single ancillary data
object, which is the recommended technique, this function
overestimates the amount of space required by the size of
.Li N-1
.Li cmsghdr
structures,
where
.Li N
is the number of options to be stored in the object.
This is of little consequence, since it is assumed that most
Hop-by-Hop option headers and Destination option headers carry only
one option
.Pq appendix B of [RFC-2460] .
.\"
.Ss inet6_option_init
.Fn inet6_option_init
is called once per ancillary data object that will
contain either Hop-by-Hop or Destination options.
It returns
.Li 0
on success or
.Li -1
on an error.
.Pp
.Fa bp
is a pointer to previously allocated space that will contain the
ancillary data object.
It must be large enough to contain all the
individual options to be added by later calls to
.Fn inet6_option_append
and
.Fn inet6_option_alloc .
.Pp
.Fa cmsgp
is a pointer to a pointer to a
.Li cmsghdr
structure.
.Fa *cmsgp
is initialized by this function to point to the
.Li cmsghdr
structure constructed by this function in the buffer pointed to by
.Fa bp .
.Pp
.Fa type
is either
.Dv IPV6_HOPOPTS
or
.Dv IPV6_DSTOPTS .
This
.Fa type
is stored in the
.Li cmsg_type
member of the
.Li cmsghdr
structure pointed to by
.Fa *cmsgp .
.\"
.Ss inet6_option_append
This function appends a Hop-by-Hop option or a Destination option
into an ancillary data object that has been initialized by
.Fn inet6_option_init .
This function returns
.Li 0
if it succeeds or
.Li -1
on an error.
.Pp
.Fa cmsg
is a pointer to the
.Li cmsghdr
structure that must have been
initialized by
.Fn inet6_option_init .
.Pp
.Fa typep
is a pointer to the 8-bit option type.
It is assumed that this
field is immediately followed by the 8-bit option data length field,
which is then followed immediately by the option data.
The caller
initializes these three fields
.Pq the type-length-value, or TLV
before calling this function.
.Pp
The option type must have a value from
.Li 2
to
.Li 255 , inclusive.
.Po
.Li 0
and
.Li 1
are reserved for the
.Li Pad1
and
.Li PadN
options, respectively.
.Pc
.Pp
The option data length must have a value between
.Li 0
and
.Li 255 ,
inclusive, and is the length of the option data that follows.
.Pp
.Fa multx
is the value
.Li x
in the alignment term
.Dq Li xn + y .
It must have a value of
.Li 1 ,
.Li 2 ,
.Li 4 ,
or
.Li 8 .
.Pp
.Fa plusy
is the value
.Li y
in the alignment term
.Dq Li xn + y .
It must have a value between
.Li 0
and
.Li 7 ,
inclusive.
.\"
.Ss inet6_option_alloc
This function appends a Hop-by-Hop option or a Destination option
into an ancillary data object that has been initialized by
.Fn inet6_option_init .
This function returns a pointer to the 8-bit
option type field that starts the option on success, or
.Dv NULL
on an error.
.Pp
The difference between this function and
.Fn inet6_option_append
is that the latter copies the contents of a previously built option into
the ancillary data object while the current function returns a
pointer to the space in the data object where the option's TLV must
then be built by the caller.
.Pp
.Fa cmsg
is a pointer to the
.Li cmsghdr
structure that must have been
initialized by
.Fn inet6_option_init .
.Pp
.Fa datalen
is the value of the option data length byte for this option.
This value is required as an argument to allow the function to
determine if padding must be appended at the end of the option.
.Po
The
.Fn inet6_option_append
function does not need a data length argument
since the option data length must already be stored by the caller.
.Pc
.Pp
.Fa multx
is the value
.Li x
in the alignment term
.Dq Li xn + y .
It must have a value of
.Li 1 ,
.Li 2 ,
.Li 4 ,
or
.Li 8 .
.Pp
.Fa plusy
is the value
.Li y
in the alignment term
.Dq Li xn + y .
It must have a value between
.Li 0
and
.Li 7 ,
inclusive.
.\"
.Ss inet6_option_next
This function processes the next Hop-by-Hop option or Destination
option in an ancillary data object.
If another option remains to be
processed, the return value of the function is
.Li 0
and
.Fa *tptrp
points to
the 8-bit option type field
.Po
which is followed by the 8-bit option
data length, followed by the option data
.Pc .
If no more options remain
to be processed, the return value is
.Li -1
and
.Fa *tptrp
is
.Dv NULL .
If an error occurs, the return value is
.Li -1
and
.Fa *tptrp
is not
.Dv NULL .
.Pp
.Fa cmsg
is a pointer to
.Li cmsghdr
structure of which
.Li cmsg_level
equals
.Dv IPPROTO_IPV6
and
.Li cmsg_type
equals either
.Dv IPV6_HOPOPTS
or
.Dv IPV6_DSTOPTS .
.Pp
.Fa tptrp
is a pointer to a pointer to an 8-bit byte and
.Fa *tptrp
is used
by the function to remember its place in the ancillary data object
each time the function is called.
The first time this function is
called for a given ancillary data object,
.Fa *tptrp
must be set to
.Dv NULL .
.Pp
Each time this function returns success,
.Fa *tptrp
points to the 8-bit
option type field for the next option to be processed.
.\"
.Ss inet6_option_find
This function is similar to the previously described
.Fn inet6_option_next
function, except this function lets the caller
specify the option type to be searched for, instead of always
returning the next option in the ancillary data object.
.Fa cmsg
is a
pointer to
.Li cmsghdr
structure of which
.Li cmsg_level
equals
.Dv IPPROTO_IPV6
and
.Li cmsg_type
equals either
.Dv IPV6_HOPOPTS
or
.Dv IPV6_DSTOPTS .
.Pp
.Fa tptrp
is a pointer to a pointer to an 8-bit byte and
.Fa *tptrp
is used
by the function to remember its place in the ancillary data object
each time the function is called.
The first time this function is
called for a given ancillary data object,
.Fa *tptrp
must be set to
.Dv NULL .
.Pa
This function starts searching for an option of the specified type
beginning after the value of
.Fa *tptrp .
If an option of the specified
type is located, this function returns
.Li 0
and
.Fa *tptrp
points to the 8-
bit option type field for the option of the specified type.
If an
option of the specified type is not located, the return value is
.Li -1
and
.Fa *tptrp
is
.Dv NULL .
If an error occurs, the return value is
.Li -1
and
.Fa *tptrp
is not
.Dv NULL .
.\"
.Sh DIAGNOSTICS
.Fn inet6_option_init
and
.Fn inet6_option_append
return
.Li 0
on success or
.Li -1
on an error.
.Pp
.Fn inet6_option_alloc
returns
.Dv NULL on an error.
.Pp
On errors,
.Fn inet6_option_next
and
.Fn inet6_option_find
return
.Li -1
setting
.Fa *tptrp
to non
.Dv NULL
value.
.\"
.Sh EXAMPLES
RFC2292 gives comprehensive examples in chapter 6.
.\"
.Sh SEE ALSO
.Rs
.%A W. Stevens
.%A M. Thomas
.%T "Advanced Sockets API for IPv6"
.%N RFC2292
.%D February 1998
.Re
.Rs
.%A S. Deering
.%A R. Hinden
.%T "Internet Protocol, Version 6 (IPv6) Specification"
.%N RFC2460
.%D December 1998
.Re
.\"
.Sh HISTORY
The implementation first appeared in KAME advanced networking kit.
.\"
.Sh STANDARDS
The functions are
are documented in
.Dq Advanced Sockets API for IPv6
.Pq RFC2292 .
.\"
.Sh BUGS
The text was shamelessly copied from RFC2292.

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@ -0,0 +1,321 @@
.\" $NetBSD: inet6_rthdr_space.3,v 1.1 1999/12/12 11:20:05 itojun Exp $
.\"
.\" Copyright (c) 1983, 1987, 1991, 1993
.\" The Regents of the University of California. 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. All advertising materials mentioning features or use of this software
.\" must display the following acknowledgement:
.\" This product includes software developed by the University of
.\" California, Berkeley and its contributors.
.\" 4. Neither the name of the University 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 REGENTS 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 REGENTS 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.
.\"
.\" KAME Id: inet6_rthdr_space.3,v 1.2 1999/12/10 07:01:02 itojun Exp
.\"
.Dd December 10, 1999
.Dt INET6_OPTION_SPACE 3
.Os
.\"
.Sh NAME
.Nm inet6_rthdr_space ,
.Nm inet6_rthdr_init ,
.Nm inet6_rthdr_add ,
.Nm inet6_rthdr_lasthop ,
.Nm inet6_rthdr_reverse ,
.Nm inet6_rthdr_segments ,
.Nm inet6_rthdr_getaddr ,
.Nm inet6_rthdr_getflags
.Nd IPv6 Routing Header Options manipulation
.\"
.Sh SYNOPSIS
.Fd #include <netinet/in.h>
.Ft size_t
.Fn inet6_rthdr_space "int type" "int segments"
.Ft "struct cmsghdr *"
.Fn inet6_rthdr_init "void *bp" "int type"
.Ft int
.Fn inet6_rthdr_add "struct cmsghdr *cmsg" "const struct in6_addr *addr" "unsigned int flags"
.Ft int
.Fn inet6_rthdr_lasthop "struct cmsghdr *cmsg" "unsigned int flags"
.Ft int
.Fn inet6_rthdr_reverse "const struct cmsghdr *in" "struct cmsghdr *out"
.Ft int
.Fn inet6_rthdr_segments "const struct cmsghdr *cmsg"
.Ft "struct in6_addr"
.Fn inet6_rthdr_getaddr "struct cmsghdr *cmsg" "int index"
.Ft int
.Fn inet6_rthdr_getflags "const struct cmsghdr *cmsg" "int index"
.\"
.Sh DESCRIPTION
RFC2292 IPv6 advanced API defines eight
functions that the application calls to build and examine a Routing
header. Four functions build a Routing header:
.Bl -hang
.It Fn inet6_rthdr_space
return #bytes required for ancillary data
.It Fn inet6_rthdr_init
initialize ancillary data for Routing header
.It Fn inet6_rthdr_add
add IPv6 address & flags to Routing header
.It Fn inet6_rthdr_lasthop
specify the flags for the final hop
.El
.Pp
Four functions deal with a returned Routing header:
.Bl -hang
.It Fn inet6_rthdr_reverse
reverse a Routing header
.It Fn inet6_rthdr_segments
return #segments in a Routing header
.It Fn inet6_rthdr_getaddr
fetch one address from a Routing header
.It Fn inet6_rthdr_getflags
fetch one flag from a Routing header
.El
.Pp
The function prototypes for these functions are all in the
.Aq Li netinet/in.h
header.
.\"
.Ss inet6_rthdr_space
This function returns the number of bytes required to hold a Routing
header of the specified
.Fa type
containing the specified number of
.Fa segments
.Pq addresses .
For an IPv6 Type 0 Routing header, the number
of segments must be between 1 and 23, inclusive. The return value
includes the size of the cmsghdr structure that precedes the Routing
header, and any required padding.
.Pp
If the return value is 0, then either the type of the Routing header
is not supported by this implementation or the number of segments is
invalid for this type of Routing header.
.Pp
Note: This function returns the size but does not allocate the space
required for the ancillary data.
This allows an application to
allocate a larger buffer, if other ancillary data objects are
desired, since all the ancillary data objects must be specified to
.Xr sendmsg 2
as a single
.Li msg_control
buffer.
.\"
.Ss inet6_rthdr_init
This function initializes the buffer pointed to by
.Fa bp
to contain a
.Li cmsghdr
structure followed by a Routing header of the specified
.Fa type .
The
.Li cmsg_len
member of the
.Li cmsghdr
structure is initialized to the
size of the structure plus the amount of space required by the
Routing header.
The
.Li cmsg_level
and
.Li cmsg_type
members are also initialized as required.
.Pp
The caller must allocate the buffer and its size can be determined by
calling
.Fn inet6_rthdr_space .
.Pp
Upon success the return value is the pointer to the
.Li cmsghdr
structure, and this is then used as the first argument to the next
two functions.
Upon an error the return value is
.Dv NULL .
.\"
.Ss inet6_rthdr_add
This function adds the address pointed to by
.Fa addr
to the end of the
Routing header being constructed and sets the type of this hop to the
value of
.Fa flags .
For an IPv6 Type 0 Routing header,
.Fa flags
must be
either
.Dv IPV6_RTHDR_LOOSE
or
.Dv IPV6_RTHDR_STRICT .
.Pp
If successful, the
.Li cmsg_len
member of the
.Li cmsghdr
structure is
updated to account for the new address in the Routing header and the
return value of the function is 0.
Upon an error the return value of
the function is -1.
.\"
.Ss inet6_rthdr_lasthop
This function specifies the Strict/Loose flag for the final hop of a
Routing header.
For an IPv6 Type 0 Routing header,
.Fa flags
must be either
.Dv IPV6_RTHDR_LOOSE
or
.Dv IPV6_RTHDR_STRICT .
.Pp
The return value of the function is 0 upon success, or -1 upon an error.
.Pp
Notice that a Routing header specifying
.Li N
intermediate nodes requires
.Li N+1
Strict/Loose flags.
This requires
.Li N
calls to
.Fn inet6_rthdr_add
followed by one call to
.Fn inet6_rthdr_lasthop .
.\"
.Ss inet6_rthdr_reverse
This function takes a Routing header that was received as ancillary
data
.Po
pointed to by the first argument,
.Fa in
.Pc
and writes a new Routing
header that sends datagrams along the reverse of that route.
Both
arguments are allowed to point to the same buffer
.Pq that is, the reversal can occur in place .
.Pp
The return value of the function is 0 on success, or -1 upon an
error.
.\"
.Ss inet6_rthdr_segments
This function returns the number of segments
.Pq addresses
contained in
the Routing header described by
.Fa cmsg .
On success the return value is
between 1 and 23, inclusive.
The return value of the function is -1 upon an error.
.\"
.Ss inet6_rthdr_getaddr
This function returns a pointer to the IPv6 address specified by
.Fa index
.Po
which must have a value between 1 and the value returned by
.Fn inet6_rthdr_segments
.Pc
in the Routing header described by
.Fa cmsg .
An
application should first call
.Fn inet6_rthdr_segments
to obtain the number of segments in the Routing header.
.Pp
Upon an error the return value of the function is
.Dv NULL .
.\"
.Ss inet6_rthdr_getflags
This function returns the flags value specified by
.Fa index
.Po
which must
have a value between 0 and the value returned by
.Fn inet6_rthdr_segments
.Pc
in the Routing header described by
.Fa cmsg .
For an IPv6 Type 0 Routing header the return value will be either
.Dv IPV6_RTHDR_LOOSE
or
.Dv IPV6_RTHDR_STRICT .
.Pp
Upon an error the return value of the function is -1.
.Pp
Note: Addresses are indexed starting at 1, and flags starting at 0,
to maintain consistency with the terminology and figures in RFC2460.
.\"
.Sh DIAGNOSTICS
.Fn inet6_rthdr_space
returns 0 on errors.
.Pp
.Fn inet6_rthdr_add ,
.Fn inet6_rthdr_lasthop
and
.Fn inet6_rthdr_reverse
return 0 on success, and returns -1 on error.
.Pp
.Fn inet6_rthdr_init
and
.Fn inet6_rthdr_getaddr
return
.Dv NULL
on error.
.Pp
.Fn inet6_rthdr_segments
and
.Fn inet6_rthdr_getflags
return -1 on error.
.\"
.Sh EXAMPLES
RFC2292 gives comprehensive examples in chapter 8.
.\"
.Sh SEE ALSO
.Rs
.%A W. Stevens
.%A M. Thomas
.%T "Advanced Sockets API for IPv6"
.%N RFC2292
.%D February 1998
.Re
.Rs
.%A S. Deering
.%A R. Hinden
.%T "Internet Protocol, Version 6 (IPv6) Specification"
.%N RFC2460
.%D December 1998
.Re
.\"
.Sh HISTORY
The implementation first appeared in KAME advanced networking kit.
.\"
.Sh STANDARDS
The functions are
are documented in
.Dq Advanced Sockets API for IPv6
.Pq RFC2292 .
.\"
.Sh BUGS
The text was shamelessly copied from RFC2292.