1 .\" $KAME: inet6_opt_init.3,v 1.7 2004/12/27 05:08:23 itojun Exp $
3 .\" Copyright (C) 2004 WIDE Project.
4 .\" All rights reserved.
6 .\" Redistribution and use in source and binary forms, with or without
7 .\" modification, are permitted provided that the following conditions
9 .\" 1. Redistributions of source code must retain the above copyright
10 .\" notice, this list of conditions and the following disclaimer.
11 .\" 2. Redistributions in binary form must reproduce the above copyright
12 .\" notice, this list of conditions and the following disclaimer in the
13 .\" documentation and/or other materials provided with the distribution.
14 .\" 3. Neither the name of the project nor the names of its contributors
15 .\" may be used to endorse or promote products derived from this software
16 .\" without specific prior written permission.
18 .\" THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
19 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 .\" ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
22 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 .Nm inet6_opt_append ,
39 .Nm inet6_opt_finish ,
40 .Nm inet6_opt_set_val ,
44 .Nd IPv6 Hop-by-Hop and Destination Options manipulation
51 .Fn inet6_opt_init "void *extbuf" "socklen_t extlen"
53 .Fn inet6_opt_append "void *extbuf" "socklen_t extlen" "int offset" "uint8_t type" "socklen_t len" "uint8_t align" "void **databufp"
55 .Fn inet6_opt_finish "void *extbuf" "socklen_t extlen" "int offset"
57 .Fn inet6_opt_set_val "void *databuf" "int offset" "void *val" "socklen_t vallen"
59 .Fn inet6_opt_next "void *extbuf" "socklen_t extlen" "int offset" "uint8_t *typep" "socklen_t *lenp" "void **databufp"
61 .Fn inet6_opt_find "void *extbuf" "socklen_t extlen" "int offset" "uint8_t type" "socklen_t *lenp" "void **databufp"
63 .Fn inet6_opt_get_val "void *databuf" "int offset" "void *val" "socklen_t vallen"
66 Building and parsing the Hop-by-Hop and Destination options is
68 The advanced sockets API defines a set of functions to
69 help applications create and manipulate Hop-by-Hop and Destination
71 This man page describes the functions specified in
73 These functions use the
74 formatting rules specified in Appendix B in RFC 2460, i.e., that the
75 largest field is placed last in the option.
76 The function prototypes
77 for these functions are all contained in the
85 returns the number of bytes needed for an empty
86 extension header, one without any options.
89 argument points to a valid section of memory
92 function also initializes the extension header's length field.
93 When attempting to initialize an extension buffer passed in the
97 must be a positive multiple of 8 or else the function fails and
98 returns \-1 to the caller.
103 function can perform two different jobs.
106 argument is supplied it appends an option to the extension buffer and
107 returns the updated total length as well as a pointer to the newly
117 function only reports what the total length would
118 be if the option were actually appended.
123 arguments specify the length of the option and the required data
124 alignment which must be used when appending the option.
127 argument should be the length returned by the
129 function or a previous call to
130 .Fn inet6_opt_append .
134 argument is the 8-bit option type.
138 has been called, the application can use the buffer pointed to by
141 .Fn inet6_opt_set_val
142 to specify the data to be contained in the option.
153 All other values from 2 through 255 may be used by applications.
155 The length of the option data is contained in an 8-bit value and so
156 may contain any value from 0 through 255.
160 parameter must have a value of 1, 2, 4, or 8 and cannot exceed the
163 The alignment values represent no alignment, 16 bit, 32 bit and 64 bit
164 alignments, respectively.
170 calculates the final padding necessary to make the extension header a
171 multiple of 8 bytes, as required by the IPv6 extension header
172 specification, and returns the extension header's updated total
176 argument should be the length returned by
179 .Fn inet6_opt_append .
184 the function also sets up the appropriate padding bytes by inserting a
185 Pad1 or PadN option of the proper length.
187 If the extension header is too small to contain the proper padding
188 then an error of \-1 is returned to the caller.
190 .Ss inet6_opt_set_val
192 .Fn inet6_opt_set_val
193 function inserts data items of various sizes into the data portion of
197 argument is a pointer to memory that was returned by the
201 argument specifies where the option should be placed in the
205 argument points to an area of memory containing the data to be
206 inserted into the extension header, and the
208 argument indicates how much data to copy.
210 The caller should ensure that each field is aligned on its natural
211 boundaries as described in Appendix B of RFC 2460.
213 The function returns the offset for the next field which is calculated as
217 and is used when composing options with multiple fields.
222 function parses received extension headers.
227 arguments specify the location and length of the extension header
231 argument should either be zero, for the first option, or the length value
232 returned by a previous call to
236 The return value specifies the position where to continue scanning the
238 The option is returned in the arguments
243 point to the 8-bit option type, the 8-bit option length and the option
245 This function does not return any PAD1 or PADN options.
246 When an error occurs or there are no more options, the return
252 function searches the extension buffer for a particular option type,
253 passed in through the
256 If the option is found then the
260 arguments are updated to point to the option's length and data,
267 must point to a valid extension buffer and give its length.
270 argument can be used to search from a location anywhere in the
272 .Ss inet6_opt_get_val
274 .Fn inet6_opt_get_val
275 function extracts data items of various sizes in the data portion of
279 is a pointer returned by the
286 argument points to where the data will be extracted.
289 argument specifies from where in the data portion of the option the
290 value should be extracted; the first byte of option data is specified
291 by an offset of zero.
293 It is expected that each field is aligned on its natural boundaries as
294 described in Appendix B of RFC 2460.
296 The function returns the offset for the next field
301 which can be used when extracting option content with multiple fields.
302 Robust receivers must verify alignment before calling this function.
305 All the functions return
310 RFC 3542 gives comprehensive examples in Section 22.
312 KAME also provides examples in the
314 directory of its kit.
322 .%T "Advanced Sockets API for IPv6"
329 .%T "Internet Protocol, Version 6 (IPv6) Specification"
334 The functions are documented in
335 .Dq Advanced Sockets API for IPv6
339 The implementation first appeared in KAME advanced networking kit.