diff options
Diffstat (limited to 'newlib/libc/sys/linux/net/inet6_option_space.3')
| -rw-r--r-- | newlib/libc/sys/linux/net/inet6_option_space.3 | 445 |
1 files changed, 445 insertions, 0 deletions
diff --git a/newlib/libc/sys/linux/net/inet6_option_space.3 b/newlib/libc/sys/linux/net/inet6_option_space.3 new file mode 100644 index 000000000..328c70f48 --- /dev/null +++ b/newlib/libc/sys/linux/net/inet6_option_space.3 @@ -0,0 +1,445 @@ +.\" 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. +.\" +.\" $Id$ +.\" $FreeBSD: src/lib/libc/net/inet6_option_space.3,v 1.8 2001/10/01 16:08:55 ru 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 LIBRARY +.Lb libc +.Sh SYNOPSIS +.In sys/types.h +.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 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 +(to make its size a multiple of 8 bytes). +The argument is the size of the structure defining the option, +which must include any pad bytes at the beginning +(the value +.Li y +in the alignment term +.Dq Li "xn + y" ) , +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 +(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 +(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. +.Li ( 0 +and +.Li 1 +are reserved for the +.Li Pad1 +and +.Li PadN +options, respectively.) +.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. +(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.) +.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 +(which is followed by the 8-bit option +data length, followed by the option data). +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 documented in +.Dq Advanced Sockets API for IPv6 +(RFC2292). +.\" +.Sh BUGS +The text was shamelessly copied from RFC2292. |