b6cbf7203b
This patch imports the unmodified current version of NetBSD libc. The NetBSD includes are in /nbsd_include, while the libc code itself is split between lib/nbsd_libc and common/lib/libc.
448 lines
10 KiB
Groff
448 lines
10 KiB
Groff
.\" $NetBSD: inet6_option_space.3,v 1.3 2010/03/22 19:30:54 joerg Exp $
|
|
.\" $KAME: inet6_option_space.3,v 1.7 2000/05/17 14:32:13 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. 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.
|
|
.\"
|
|
.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
|
|
.In netinet/in.h
|
|
.Ft "int"
|
|
.Fn inet6_option_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 uint8_t *typep" "int multx" "int plusy"
|
|
.Ft "uint8_t *"
|
|
.Fn inet6_option_alloc "struct cmsghdr *cmsg" "int datalen" "int multx" "int plusy"
|
|
.Ft "int"
|
|
.Fn inet6_option_next "const struct cmsghdr *cmsg" "uint8_t **tptrp"
|
|
.Ft "int"
|
|
.Fn inet6_option_find "const struct cmsghdr *cmsg" "uint8_t **tptrp" "int type"
|
|
.\"
|
|
.Sh DESCRIPTION
|
|
.\"
|
|
Building and parsing the Hop-by-Hop and Destination options is
|
|
complicated due to alignment constraints, padding and
|
|
ancillary data manipulation.
|
|
RFC 2292 defines a set of functions to help the application.
|
|
The function prototypes for
|
|
these functions are all in the
|
|
.In 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 EXAMPLES
|
|
RFC 2292 gives comprehensive examples in chapter 6.
|
|
.\"
|
|
.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 SEE ALSO
|
|
.Rs
|
|
.%A W. Stevens
|
|
.%A M. Thomas
|
|
.%T "Advanced Sockets API for IPv6"
|
|
.%N RFC 2292
|
|
.%D February 1998
|
|
.Re
|
|
.Rs
|
|
.%A S. Deering
|
|
.%A R. Hinden
|
|
.%T "Internet Protocol, Version 6 (IPv6) Specification"
|
|
.%N RFC 2460
|
|
.%D December 1998
|
|
.Re
|
|
.\"
|
|
.Sh STANDARDS
|
|
The functions
|
|
are documented in
|
|
.Dq Advanced Sockets API for IPv6
|
|
.Pq RFC 2292 .
|
|
.\"
|
|
.Sh HISTORY
|
|
The implementation first appeared in KAME advanced networking kit.
|
|
.\"
|
|
.Sh BUGS
|
|
The text was shamelessly copied from RFC 2292.
|