2 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
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29 * $FreeBSD: src/lib/libc/net/ip6opt.c,v 1.1 1999/12/16 18:32:01 shin Exp $
30 * $DragonFly: src/lib/libc/net/ip6opt.c,v 1.6 2007/05/29 10:58:11 hasso Exp $
33 #include <sys/param.h>
34 #include <sys/types.h>
35 #include <sys/socket.h>
37 #include <netinet/in.h>
38 #include <netinet/ip6.h>
43 static int ip6optlen(u_int8_t
*opt
, u_int8_t
*lim
);
44 static void inet6_insert_padopt(u_char
*p
, int len
);
47 * This function returns the number of bytes required to hold an option
48 * when it is stored as ancillary data, including the cmsghdr structure
49 * at the beginning, and any padding at the end (to make its size a
50 * multiple of 8 bytes). The argument is the size of the structure
51 * defining the option, which must include any pad bytes at the
52 * beginning (the value y in the alignment term "xn + y"), the type
53 * byte, the length byte, and the option data.
56 inet6_option_space(int nbytes
)
58 nbytes
+= 2; /* we need space for nxt-hdr and length fields */
59 return(CMSG_SPACE((nbytes
+ 7) & ~7));
63 * This function is called once per ancillary data object that will
64 * contain either Hop-by-Hop or Destination options. It returns 0 on
65 * success or -1 on an error.
68 inet6_option_init(void *bp
, struct cmsghdr
**cmsgp
, int type
)
70 struct cmsghdr
*ch
= (struct cmsghdr
*)bp
;
72 /* argument validation */
73 if (type
!= IPV6_HOPOPTS
&& type
!= IPV6_DSTOPTS
)
76 ch
->cmsg_level
= IPPROTO_IPV6
;
78 ch
->cmsg_len
= CMSG_LEN(0);
85 * This function appends a Hop-by-Hop option or a Destination option
86 * into an ancillary data object that has been initialized by
87 * inet6_option_init(). This function returns 0 if it succeeds or -1 on
89 * multx is the value x in the alignment term "xn + y" described
90 * earlier. It must have a value of 1, 2, 4, or 8.
91 * plusy is the value y in the alignment term "xn + y" described
92 * earlier. It must have a value between 0 and 7, inclusive.
95 inet6_option_append(struct cmsghdr
*cmsg
, const u_int8_t
*typep
, int multx
,
98 int padlen
, optlen
, off
;
99 u_char
*bp
= (u_char
*)cmsg
+ cmsg
->cmsg_len
;
100 struct ip6_ext
*eh
= (struct ip6_ext
*)CMSG_DATA(cmsg
);
102 /* argument validation */
103 if (multx
!= 1 && multx
!= 2 && multx
!= 4 && multx
!= 8)
105 if (plusy
< 0 || plusy
> 7)
109 * If this is the first option, allocate space for the
110 * first 2 bytes(for next header and length fields) of
113 if (bp
== (u_char
*)eh
) {
118 /* calculate pad length before the option. */
119 off
= bp
- (u_char
*)eh
;
120 padlen
= (((off
% multx
) + (multx
- 1)) & ~(multx
- 1)) -
124 inet6_insert_padopt(bp
, padlen
);
125 cmsg
->cmsg_len
+= padlen
;
128 /* copy the option */
129 if (typep
[0] == IP6OPT_PAD1
)
132 optlen
= typep
[1] + 2;
133 memcpy(bp
, typep
, optlen
);
135 cmsg
->cmsg_len
+= optlen
;
137 /* calculate pad length after the option and insert the padding */
138 off
= bp
- (u_char
*)eh
;
139 padlen
= ((off
+ 7) & ~7) - off
;
140 inet6_insert_padopt(bp
, padlen
);
142 cmsg
->cmsg_len
+= padlen
;
144 /* update the length field of the ip6 option header */
145 eh
->ip6e_len
= ((bp
- (u_char
*)eh
) >> 3) - 1;
151 * This function appends a Hop-by-Hop option or a Destination option
152 * into an ancillary data object that has been initialized by
153 * inet6_option_init(). This function returns a pointer to the 8-bit
154 * option type field that starts the option on success, or NULL on an
156 * The difference between this function and inet6_option_append() is
157 * that the latter copies the contents of a previously built option into
158 * the ancillary data object while the current function returns a
159 * pointer to the space in the data object where the option's TLV must
160 * then be built by the caller.
164 inet6_option_alloc(struct cmsghdr
*cmsg
, int datalen
, int multx
, int plusy
)
167 u_int8_t
*bp
= (u_char
*)cmsg
+ cmsg
->cmsg_len
;
169 struct ip6_ext
*eh
= (struct ip6_ext
*)CMSG_DATA(cmsg
);
171 /* argument validation */
172 if (multx
!= 1 && multx
!= 2 && multx
!= 4 && multx
!= 8)
174 if (plusy
< 0 || plusy
> 7)
178 * If this is the first option, allocate space for the
179 * first 2 bytes(for next header and length fields) of
182 if (bp
== (u_char
*)eh
) {
187 /* calculate pad length before the option. */
188 off
= bp
- (u_char
*)eh
;
189 padlen
= (((off
% multx
) + (multx
- 1)) & ~(multx
- 1)) -
193 inet6_insert_padopt(bp
, padlen
);
194 cmsg
->cmsg_len
+= padlen
;
197 /* keep space to store specified length of data */
200 cmsg
->cmsg_len
+= datalen
;
202 /* calculate pad length after the option and insert the padding */
203 off
= bp
- (u_char
*)eh
;
204 padlen
= ((off
+ 7) & ~7) - off
;
205 inet6_insert_padopt(bp
, padlen
);
207 cmsg
->cmsg_len
+= padlen
;
209 /* update the length field of the ip6 option header */
210 eh
->ip6e_len
= ((bp
- (u_char
*)eh
) >> 3) - 1;
216 * This function processes the next Hop-by-Hop option or Destination
217 * option in an ancillary data object. If another option remains to be
218 * processed, the return value of the function is 0 and *tptrp points to
219 * the 8-bit option type field (which is followed by the 8-bit option
220 * data length, followed by the option data). If no more options remain
221 * to be processed, the return value is -1 and *tptrp is NULL. If an
222 * error occurs, the return value is -1 and *tptrp is not NULL.
226 inet6_option_next(const struct cmsghdr
*cmsg
, u_int8_t
**tptrp
)
228 struct ip6_ext
*ip6e
;
232 if (cmsg
->cmsg_level
!= IPPROTO_IPV6
||
233 (cmsg
->cmsg_type
!= IPV6_HOPOPTS
&&
234 cmsg
->cmsg_type
!= IPV6_DSTOPTS
))
237 /* message length validation */
238 if (cmsg
->cmsg_len
< CMSG_SPACE(sizeof(struct ip6_ext
)))
240 ip6e
= (struct ip6_ext
*)CMSG_DATA(cmsg
);
241 hdrlen
= (ip6e
->ip6e_len
+ 1) << 3;
242 if (cmsg
->cmsg_len
< CMSG_SPACE(hdrlen
))
246 * If the caller does not specify the starting point,
247 * simply return the 1st option.
248 * Otherwise, search the option list for the next option.
250 lim
= (u_int8_t
*)ip6e
+ hdrlen
;
252 *tptrp
= (u_int8_t
*)(ip6e
+ 1);
254 if ((optlen
= ip6optlen(*tptrp
, lim
)) == 0)
257 *tptrp
= *tptrp
+ optlen
;
259 if (*tptrp
>= lim
) { /* there is no option */
264 * Finally, checks if the next option is safely stored in the
267 if (ip6optlen(*tptrp
, lim
) == 0)
274 * This function is similar to the inet6_option_next() function,
275 * except this function lets the caller specify the option type to be
276 * searched for, instead of always returning the next option in the
277 * ancillary data object.
278 * Note: RFC 2292 says the type of tptrp is u_int8_t *, but we think
279 * it's a typo. The variable should be type of u_int8_t **.
282 inet6_option_find(const struct cmsghdr
*cmsg
, u_int8_t
**tptrp
, int type
)
284 struct ip6_ext
*ip6e
;
286 u_int8_t
*optp
, *lim
;
288 if (cmsg
->cmsg_level
!= IPPROTO_IPV6
||
289 (cmsg
->cmsg_type
!= IPV6_HOPOPTS
&&
290 cmsg
->cmsg_type
!= IPV6_DSTOPTS
))
293 /* message length validation */
294 if (cmsg
->cmsg_len
< CMSG_SPACE(sizeof(struct ip6_ext
)))
296 ip6e
= (struct ip6_ext
*)CMSG_DATA(cmsg
);
297 hdrlen
= (ip6e
->ip6e_len
+ 1) << 3;
298 if (cmsg
->cmsg_len
< CMSG_SPACE(hdrlen
))
302 * If the caller does not specify the starting point,
303 * search from the beginning of the option list.
304 * Otherwise, search from *the next option* of the specified point.
306 lim
= (u_int8_t
*)ip6e
+ hdrlen
;
308 *tptrp
= (u_int8_t
*)(ip6e
+ 1);
310 if ((optlen
= ip6optlen(*tptrp
, lim
)) == 0)
313 *tptrp
= *tptrp
+ optlen
;
315 for (optp
= *tptrp
; optp
< lim
; optp
+= optlen
) {
320 if ((optlen
= ip6optlen(optp
, lim
)) == 0)
330 * Calculate the length of a given IPv6 option. Also checks
331 * if the option is safely stored in user's buffer according to the
332 * calculated length and the limitation of the buffer.
335 ip6optlen(u_int8_t
*opt
, u_int8_t
*lim
)
339 if (*opt
== IP6OPT_PAD1
)
342 /* is there enough space to store type and len? */
345 optlen
= *(opt
+ 1) + 2;
347 if (opt
+ optlen
<= lim
)
354 inet6_insert_padopt(u_char
*p
, int len
)
365 memset(&p
[2], 0, len
- 2);
371 * The following functions are defined in RFC3542, which is a successor
376 inet6_opt_init(void *extbuf
, socklen_t extlen
)
378 struct ip6_ext
*ext
= (struct ip6_ext
*)extbuf
;
380 if (extlen
< 0 || (extlen
% 8))
386 ext
->ip6e_len
= (extlen
>> 3) - 1;
389 return (2); /* sizeof the next and the length fields */
393 inet6_opt_append(void *extbuf
, socklen_t extlen
, int offset
, u_int8_t type
,
394 socklen_t len
, u_int8_t align
, void **databufp
)
396 int currentlen
= offset
, padlen
= 0;
399 * The option type must have a value from 2 to 255, inclusive.
400 * (0 and 1 are reserved for the Pad1 and PadN options, respectively.)
402 #if 0 /* always false */
403 if (type
< 2 || type
> 255)
410 * The option data length must have a value between 0 and 255,
411 * inclusive, and is the length of the option data that follows.
413 if (len
< 0 || len
> 255)
417 * The align parameter must have a value of 1, 2, 4, or 8.
418 * The align value can not exceed the value of len.
420 if (align
!= 1 && align
!= 2 && align
!= 4 && align
!= 8)
425 /* Calculate the padding length. */
426 currentlen
+= 2 + len
; /* 2 means "type + len" */
427 if (currentlen
% align
)
428 padlen
= align
- (currentlen
% align
);
430 /* The option must fit in the extension header buffer. */
431 currentlen
+= padlen
;
432 if (extlen
&& /* XXX: right? */
437 u_int8_t
*optp
= (u_int8_t
*)extbuf
+ offset
;
440 /* insert a Pad1 option */
443 } else if (padlen
> 0) {
444 /* insert a PadN option for alignment */
445 *optp
++ = IP6OPT_PADN
;
446 *optp
++ = padlen
- 2;
447 memset(optp
, 0, padlen
- 2);
448 optp
+= (padlen
- 2);
461 inet6_opt_finish(void *extbuf
, socklen_t extlen
, int offset
)
463 int updatelen
= offset
> 0 ? (1 + ((offset
- 1) | 7)) : 0;;
467 int padlen
= updatelen
- offset
;
469 if (updatelen
> extlen
)
472 padp
= (u_int8_t
*)extbuf
+ offset
;
475 else if (padlen
> 0) {
476 *padp
++ = IP6OPT_PADN
;
477 *padp
++ = (padlen
- 2);
478 memset(padp
, 0, padlen
- 2);
486 inet6_opt_set_val(void *databuf
, int offset
, void *val
, socklen_t vallen
)
489 memcpy((u_int8_t
*)databuf
+ offset
, val
, vallen
);
490 return (offset
+ vallen
);
494 inet6_opt_next(void *extbuf
, socklen_t extlen
, int offset
, u_int8_t
*typep
,
495 socklen_t
*lenp
, void **databufp
)
497 u_int8_t
*optp
, *lim
;
500 /* Validate extlen. XXX: is the variable really necessary?? */
501 if (extlen
== 0 || (extlen
% 8))
503 lim
= (u_int8_t
*)extbuf
+ extlen
;
506 * If this is the first time this function called for this options
507 * header, simply return the 1st option.
508 * Otherwise, search the option list for the next option.
511 optp
= (u_int8_t
*)((struct ip6_hbh
*)extbuf
+ 1);
513 optp
= (u_int8_t
*)extbuf
+ offset
;
515 /* Find the next option skipping any padding options. */
522 if ((optlen
= ip6optlen(optp
, lim
)) == 0)
527 if ((optlen
= ip6optlen(optp
, lim
)) == 0)
531 *databufp
= optp
+ 2;
532 return (optp
+ optlen
- (u_int8_t
*)extbuf
);
537 *databufp
= NULL
; /* for safety */
542 inet6_opt_find(void *extbuf
, socklen_t extlen
, int offset
, u_int8_t type
,
543 socklen_t
*lenp
, void **databufp
)
545 u_int8_t
*optp
, *lim
;
548 /* Validate extlen. XXX: is the variable really necessary?? */
549 if (extlen
== 0 || (extlen
% 8))
551 lim
= (u_int8_t
*)extbuf
+ extlen
;
554 * If this is the first time this function called for this options
555 * header, simply return the 1st option.
556 * Otherwise, search the option list for the next option.
559 optp
= (u_int8_t
*)((struct ip6_hbh
*)extbuf
+ 1);
561 optp
= (u_int8_t
*)extbuf
+ offset
;
563 /* Find the specified option */
565 if ((optlen
= ip6optlen(optp
, lim
)) == 0)
568 if (*optp
== type
) { /* found */
570 *databufp
= optp
+ 2;
571 return (optp
+ optlen
- (u_int8_t
*)extbuf
);
578 *databufp
= NULL
; /* for safety */
583 inet6_opt_get_val(void *databuf
, int offset
, void *val
, socklen_t vallen
)
586 /* we can't assume alignment here */
587 memcpy(val
, (u_int8_t
*)databuf
+ offset
, vallen
);
589 return (offset
+ vallen
);