1/*
2 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
3 * Copyright (c) 1996,1999 by Internet Software Consortium.
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
15 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18#if !defined(_LIBC) && !defined(lint)
19static const char rcsid[] = "$BINDId: ns_name.c,v 8.15 2000/03/30 22:53:46 vixie Exp $";
20#endif
21
22#include <sys/types.h>
23
24#include <netinet/in.h>
25#include <arpa/nameser.h>
26
27#include <errno.h>
28#include <resolv.h>
29#include <string.h>
30#include <ctype.h>
31#include <stdlib.h>
32#include <limits.h>
33
34# define SPRINTF(x) ((size_t)sprintf x)
35
36#define NS_TYPE_ELT 0x40 /*%< EDNS0 extended label type */
37#define DNS_LABELTYPE_BITSTRING 0x41
38
39/* Data. */
40
41static const char digits[] = "0123456789";
42
43static const char digitvalue[256] = {
44 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*16*/
45 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*32*/
46 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*48*/
47 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1, /*64*/
48 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*80*/
49 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*96*/
50 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*112*/
51 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*128*/
52 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
53 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
54 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
55 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
56 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
57 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
58 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
59 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*256*/
60};
61
62/* Forward. */
63
64static int special(int);
65static int printable(int);
66static int dn_find(const u_char *, const u_char *,
67 const u_char * const *,
68 const u_char * const *);
69static int encode_bitstring(const char **, const char *,
70 unsigned char **, unsigned char **,
71 unsigned const char *);
72static int labellen(const u_char *);
73static int decode_bitstring(const unsigned char **,
74 char *, const char *);
75
76/* Public. */
77
78/*%
79 * Convert an encoded domain name to printable ascii as per RFC1035.
80
81 * return:
82 *\li Number of bytes written to buffer, or -1 (with errno set)
83 *
84 * notes:
85 *\li The root is returned as "."
86 *\li All other domains are returned in non absolute form
87 */
88int
89ns_name_ntop(const u_char *src, char *dst, size_t dstsiz)
90{
91 const u_char *cp;
92 char *dn, *eom;
93 u_char c;
94 u_int n;
95 int l;
96
97 cp = src;
98 dn = dst;
99 eom = dst + dstsiz;
100
101 while ((n = *cp++) != 0) {
102 if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
103 /* Some kind of compression pointer. */
104 __set_errno (EMSGSIZE);
105 return (-1);
106 }
107 if (dn != dst) {
108 if (dn >= eom) {
109 __set_errno (EMSGSIZE);
110 return (-1);
111 }
112 *dn++ = '.';
113 }
114 if ((l = labellen(cp - 1)) < 0) {
115 __set_errno (EMSGSIZE);
116 return(-1);
117 }
118 if (dn + l >= eom) {
119 __set_errno (EMSGSIZE);
120 return (-1);
121 }
122 if ((n & NS_CMPRSFLGS) == NS_TYPE_ELT) {
123 int m;
124
125 if (n != DNS_LABELTYPE_BITSTRING) {
126 /* XXX: labellen should reject this case */
127 __set_errno (EINVAL);
128 return(-1);
129 }
130 if ((m = decode_bitstring(&cp, dn, eom)) < 0)
131 {
132 __set_errno (EMSGSIZE);
133 return(-1);
134 }
135 dn += m;
136 continue;
137 }
138 for ((void)NULL; l > 0; l--) {
139 c = *cp++;
140 if (special(c)) {
141 if (dn + 1 >= eom) {
142 __set_errno (EMSGSIZE);
143 return (-1);
144 }
145 *dn++ = '\\';
146 *dn++ = (char)c;
147 } else if (!printable(c)) {
148 if (dn + 3 >= eom) {
149 __set_errno (EMSGSIZE);
150 return (-1);
151 }
152 *dn++ = '\\';
153 *dn++ = digits[c / 100];
154 *dn++ = digits[(c % 100) / 10];
155 *dn++ = digits[c % 10];
156 } else {
157 if (dn >= eom) {
158 __set_errno (EMSGSIZE);
159 return (-1);
160 }
161 *dn++ = (char)c;
162 }
163 }
164 }
165 if (dn == dst) {
166 if (dn >= eom) {
167 __set_errno (EMSGSIZE);
168 return (-1);
169 }
170 *dn++ = '.';
171 }
172 if (dn >= eom) {
173 __set_errno (EMSGSIZE);
174 return (-1);
175 }
176 *dn++ = '\0';
177 return (dn - dst);
178}
179libresolv_hidden_def (ns_name_ntop)
180strong_alias (ns_name_ntop, __ns_name_ntop)
181
182/*%
183 * Convert an ascii string into an encoded domain name as per RFC1035.
184 *
185 * return:
186 *
187 *\li -1 if it fails
188 *\li 1 if string was fully qualified
189 *\li 0 is string was not fully qualified
190 *
191 * notes:
192 *\li Enforces label and domain length limits.
193 */
194
195int
196ns_name_pton(const char *src, u_char *dst, size_t dstsiz)
197{
198 u_char *label, *bp, *eom;
199 int c, n, escaped, e = 0;
200 char *cp;
201
202 escaped = 0;
203 bp = dst;
204 eom = dst + dstsiz;
205 label = bp++;
206
207 while ((c = *src++) != 0) {
208 if (escaped) {
209 if (c == '[') { /*%< start a bit string label */
210 if ((cp = strchr(src, ']')) == NULL) {
211 __set_errno (EINVAL);
212 return(-1);
213 }
214 if ((e = encode_bitstring(&src, cp + 2,
215 &label, &bp, eom))
216 != 0) {
217 __set_errno (e);
218 return(-1);
219 }
220 escaped = 0;
221 label = bp++;
222 if ((c = *src++) == 0)
223 goto done;
224 else if (c != '.') {
225 __set_errno (EINVAL);
226 return(-1);
227 }
228 continue;
229 }
230 else if ((cp = strchr(digits, c)) != NULL) {
231 n = (cp - digits) * 100;
232 if ((c = *src++) == 0 ||
233 (cp = strchr(digits, c)) == NULL) {
234 __set_errno (EMSGSIZE);
235 return (-1);
236 }
237 n += (cp - digits) * 10;
238 if ((c = *src++) == 0 ||
239 (cp = strchr(digits, c)) == NULL) {
240 __set_errno (EMSGSIZE);
241 return (-1);
242 }
243 n += (cp - digits);
244 if (n > 255) {
245 __set_errno (EMSGSIZE);
246 return (-1);
247 }
248 c = n;
249 }
250 escaped = 0;
251 } else if (c == '\\') {
252 escaped = 1;
253 continue;
254 } else if (c == '.') {
255 c = (bp - label - 1);
256 if ((c & NS_CMPRSFLGS) != 0) { /*%< Label too big. */
257 __set_errno (EMSGSIZE);
258 return (-1);
259 }
260 if (label >= eom) {
261 __set_errno (EMSGSIZE);
262 return (-1);
263 }
264 *label = c;
265 /* Fully qualified ? */
266 if (*src == '\0') {
267 if (c != 0) {
268 if (bp >= eom) {
269 __set_errno (EMSGSIZE);
270 return (-1);
271 }
272 *bp++ = '\0';
273 }
274 if ((bp - dst) > MAXCDNAME) {
275 __set_errno (EMSGSIZE);
276 return (-1);
277 }
278 return (1);
279 }
280 if (c == 0 || *src == '.') {
281 __set_errno (EMSGSIZE);
282 return (-1);
283 }
284 label = bp++;
285 continue;
286 }
287 if (bp >= eom) {
288 __set_errno (EMSGSIZE);
289 return (-1);
290 }
291 *bp++ = (u_char)c;
292 }
293 c = (bp - label - 1);
294 if ((c & NS_CMPRSFLGS) != 0) { /*%< Label too big. */
295 __set_errno (EMSGSIZE);
296 return (-1);
297 }
298 done:
299 if (label >= eom) {
300 __set_errno (EMSGSIZE);
301 return (-1);
302 }
303 *label = c;
304 if (c != 0) {
305 if (bp >= eom) {
306 __set_errno (EMSGSIZE);
307 return (-1);
308 }
309 *bp++ = 0;
310 }
311 if ((bp - dst) > MAXCDNAME) { /*%< src too big */
312 __set_errno (EMSGSIZE);
313 return (-1);
314 }
315 return (0);
316}
317libresolv_hidden_def (ns_name_pton)
318
319/*%
320 * Convert a network strings labels into all lowercase.
321 *
322 * return:
323 *\li Number of bytes written to buffer, or -1 (with errno set)
324 *
325 * notes:
326 *\li Enforces label and domain length limits.
327 */
328
329int
330ns_name_ntol(const u_char *src, u_char *dst, size_t dstsiz)
331{
332 const u_char *cp;
333 u_char *dn, *eom;
334 u_char c;
335 u_int n;
336 int l;
337
338 cp = src;
339 dn = dst;
340 eom = dst + dstsiz;
341
342 if (dn >= eom) {
343 __set_errno (EMSGSIZE);
344 return (-1);
345 }
346 while ((n = *cp++) != 0) {
347 if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
348 /* Some kind of compression pointer. */
349 __set_errno (EMSGSIZE);
350 return (-1);
351 }
352 *dn++ = n;
353 if ((l = labellen(cp - 1)) < 0) {
354 __set_errno (EMSGSIZE);
355 return (-1);
356 }
357 if (dn + l >= eom) {
358 __set_errno (EMSGSIZE);
359 return (-1);
360 }
361 for ((void)NULL; l > 0; l--) {
362 c = *cp++;
363 if (isupper(c))
364 *dn++ = tolower(c);
365 else
366 *dn++ = c;
367 }
368 }
369 *dn++ = '\0';
370 return (dn - dst);
371}
372
373/*%
374 * Unpack a domain name from a message, source may be compressed.
375 *
376 * return:
377 *\li -1 if it fails, or consumed octets if it succeeds.
378 */
379int
380ns_name_unpack(const u_char *msg, const u_char *eom, const u_char *src,
381 u_char *dst, size_t dstsiz)
382{
383 const u_char *srcp, *dstlim;
384 u_char *dstp;
385 int n, len, checked, l;
386
387 len = -1;
388 checked = 0;
389 dstp = dst;
390 srcp = src;
391 dstlim = dst + dstsiz;
392 if (srcp < msg || srcp >= eom) {
393 __set_errno (EMSGSIZE);
394 return (-1);
395 }
396 /* Fetch next label in domain name. */
397 while ((n = *srcp++) != 0) {
398 /* Check for indirection. */
399 switch (n & NS_CMPRSFLGS) {
400 case 0:
401 case NS_TYPE_ELT:
402 /* Limit checks. */
403 if ((l = labellen(srcp - 1)) < 0) {
404 __set_errno (EMSGSIZE);
405 return(-1);
406 }
407 if (dstp + l + 1 >= dstlim || srcp + l >= eom) {
408 __set_errno (EMSGSIZE);
409 return (-1);
410 }
411 checked += l + 1;
412 *dstp++ = n;
413 memcpy(dstp, srcp, l);
414 dstp += l;
415 srcp += l;
416 break;
417
418 case NS_CMPRSFLGS:
419 if (srcp >= eom) {
420 __set_errno (EMSGSIZE);
421 return (-1);
422 }
423 if (len < 0)
424 len = srcp - src + 1;
425 srcp = msg + (((n & 0x3f) << 8) | (*srcp & 0xff));
426 if (srcp < msg || srcp >= eom) { /*%< Out of range. */
427 __set_errno (EMSGSIZE);
428 return (-1);
429 }
430 checked += 2;
431 /*
432 * Check for loops in the compressed name;
433 * if we've looked at the whole message,
434 * there must be a loop.
435 */
436 if (checked >= eom - msg) {
437 __set_errno (EMSGSIZE);
438 return (-1);
439 }
440 break;
441
442 default:
443 __set_errno (EMSGSIZE);
444 return (-1); /*%< flag error */
445 }
446 }
447 *dstp = '\0';
448 if (len < 0)
449 len = srcp - src;
450 return (len);
451}
452libresolv_hidden_def (ns_name_unpack)
453strong_alias (ns_name_unpack, __ns_name_unpack)
454
455/*%
456 * Pack domain name 'domain' into 'comp_dn'.
457 *
458 * return:
459 *\li Size of the compressed name, or -1.
460 *
461 * notes:
462 *\li 'dnptrs' is an array of pointers to previous compressed names.
463 *\li dnptrs[0] is a pointer to the beginning of the message. The array
464 * ends with NULL.
465 *\li 'lastdnptr' is a pointer to the end of the array pointed to
466 * by 'dnptrs'.
467 *
468 * Side effects:
469 *\li The list of pointers in dnptrs is updated for labels inserted into
470 * the message as we compress the name. If 'dnptr' is NULL, we don't
471 * try to compress names. If 'lastdnptr' is NULL, we don't update the
472 * list.
473 */
474int
475ns_name_pack(const u_char *src, u_char *dst, int dstsiz,
476 const u_char **dnptrs, const u_char **lastdnptr)
477{
478 u_char *dstp;
479 const u_char **cpp, **lpp, *eob, *msg;
480 const u_char *srcp;
481 int n, l, first = 1;
482
483 srcp = src;
484 dstp = dst;
485 eob = dstp + dstsiz;
486 lpp = cpp = NULL;
487 if (dnptrs != NULL) {
488 if ((msg = *dnptrs++) != NULL) {
489 for (cpp = dnptrs; *cpp != NULL; cpp++)
490 (void)NULL;
491 lpp = cpp; /*%< end of list to search */
492 }
493 } else
494 msg = NULL;
495
496 /* make sure the domain we are about to add is legal */
497 l = 0;
498 do {
499 int l0;
500
501 n = *srcp;
502 if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
503 __set_errno (EMSGSIZE);
504 return (-1);
505 }
506 if ((l0 = labellen(srcp)) < 0) {
507 __set_errno (EINVAL);
508 return(-1);
509 }
510 l += l0 + 1;
511 if (l > MAXCDNAME) {
512 __set_errno (EMSGSIZE);
513 return (-1);
514 }
515 srcp += l0 + 1;
516 } while (n != 0);
517
518 /* from here on we need to reset compression pointer array on error */
519 srcp = src;
520 do {
521 /* Look to see if we can use pointers. */
522 n = *srcp;
523 if (n != 0 && msg != NULL) {
524 l = dn_find(srcp, msg, (const u_char * const *)dnptrs,
525 (const u_char * const *)lpp);
526 if (l >= 0) {
527 if (dstp + 1 >= eob) {
528 goto cleanup;
529 }
530 *dstp++ = (l >> 8) | NS_CMPRSFLGS;
531 *dstp++ = l % 256;
532 return (dstp - dst);
533 }
534 /* Not found, save it. */
535 if (lastdnptr != NULL && cpp < lastdnptr - 1 &&
536 (dstp - msg) < 0x4000 && first) {
537 *cpp++ = dstp;
538 *cpp = NULL;
539 first = 0;
540 }
541 }
542 /* copy label to buffer */
543 if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
544 /* Should not happen. */
545 goto cleanup;
546 }
547 n = labellen(srcp);
548 if (dstp + 1 + n >= eob) {
549 goto cleanup;
550 }
551 memcpy(dstp, srcp, n + 1);
552 srcp += n + 1;
553 dstp += n + 1;
554 } while (n != 0);
555
556 if (dstp > eob) {
557cleanup:
558 if (msg != NULL)
559 *lpp = NULL;
560 __set_errno (EMSGSIZE);
561 return (-1);
562 }
563 return (dstp - dst);
564}
565libresolv_hidden_def (ns_name_pack)
566
567/*%
568 * Expand compressed domain name to presentation format.
569 *
570 * return:
571 *\li Number of bytes read out of `src', or -1 (with errno set).
572 *
573 * note:
574 *\li Root domain returns as "." not "".
575 */
576int
577ns_name_uncompress(const u_char *msg, const u_char *eom, const u_char *src,
578 char *dst, size_t dstsiz)
579{
580 u_char tmp[NS_MAXCDNAME];
581 int n;
582
583 if ((n = ns_name_unpack(msg, eom, src, tmp, sizeof tmp)) == -1)
584 return (-1);
585 if (ns_name_ntop(tmp, dst, dstsiz) == -1)
586 return (-1);
587 return (n);
588}
589libresolv_hidden_def (ns_name_uncompress)
590
591/*%
592 * Compress a domain name into wire format, using compression pointers.
593 *
594 * return:
595 *\li Number of bytes consumed in `dst' or -1 (with errno set).
596 *
597 * notes:
598 *\li 'dnptrs' is an array of pointers to previous compressed names.
599 *\li dnptrs[0] is a pointer to the beginning of the message.
600 *\li The list ends with NULL. 'lastdnptr' is a pointer to the end of the
601 * array pointed to by 'dnptrs'. Side effect is to update the list of
602 * pointers for labels inserted into the message as we compress the name.
603 *\li If 'dnptr' is NULL, we don't try to compress names. If 'lastdnptr'
604 * is NULL, we don't update the list.
605 */
606int
607ns_name_compress(const char *src, u_char *dst, size_t dstsiz,
608 const u_char **dnptrs, const u_char **lastdnptr)
609{
610 u_char tmp[NS_MAXCDNAME];
611
612 if (ns_name_pton(src, tmp, sizeof tmp) == -1)
613 return (-1);
614 return (ns_name_pack(tmp, dst, dstsiz, dnptrs, lastdnptr));
615}
616libresolv_hidden_def (ns_name_compress)
617
618/*%
619 * Reset dnptrs so that there are no active references to pointers at or
620 * after src.
621 */
622void
623ns_name_rollback(const u_char *src, const u_char **dnptrs,
624 const u_char **lastdnptr)
625{
626 while (dnptrs < lastdnptr && *dnptrs != NULL) {
627 if (*dnptrs >= src) {
628 *dnptrs = NULL;
629 break;
630 }
631 dnptrs++;
632 }
633}
634
635/*%
636 * Advance *ptrptr to skip over the compressed name it points at.
637 *
638 * return:
639 *\li 0 on success, -1 (with errno set) on failure.
640 */
641int
642ns_name_skip(const u_char **ptrptr, const u_char *eom)
643{
644 const u_char *cp;
645 u_int n;
646 int l;
647
648 cp = *ptrptr;
649 while (cp < eom && (n = *cp++) != 0) {
650 /* Check for indirection. */
651 switch (n & NS_CMPRSFLGS) {
652 case 0: /*%< normal case, n == len */
653 cp += n;
654 continue;
655 case NS_TYPE_ELT: /*%< EDNS0 extended label */
656 if ((l = labellen(cp - 1)) < 0) {
657 __set_errno (EMSGSIZE);
658 return(-1);
659 }
660 cp += l;
661 continue;
662 case NS_CMPRSFLGS: /*%< indirection */
663 cp++;
664 break;
665 default: /*%< illegal type */
666 __set_errno (EMSGSIZE);
667 return (-1);
668 }
669 break;
670 }
671 if (cp > eom) {
672 __set_errno (EMSGSIZE);
673 return (-1);
674 }
675 *ptrptr = cp;
676 return (0);
677}
678libresolv_hidden_def (ns_name_skip)
679
680/* Private. */
681
682/*%
683 * Thinking in noninternationalized USASCII (per the DNS spec),
684 * is this character special ("in need of quoting") ?
685 *
686 * return:
687 *\li boolean.
688 */
689static int
690special(int ch) {
691 switch (ch) {
692 case 0x22: /*%< '"' */
693 case 0x2E: /*%< '.' */
694 case 0x3B: /*%< ';' */
695 case 0x5C: /*%< '\\' */
696 case 0x28: /*%< '(' */
697 case 0x29: /*%< ')' */
698 /* Special modifiers in zone files. */
699 case 0x40: /*%< '@' */
700 case 0x24: /*%< '$' */
701 return (1);
702 default:
703 return (0);
704 }
705}
706
707/*%
708 * Thinking in noninternationalized USASCII (per the DNS spec),
709 * is this character visible and not a space when printed ?
710 *
711 * return:
712 *\li boolean.
713 */
714static int
715printable(int ch) {
716 return (ch > 0x20 && ch < 0x7f);
717}
718
719/*%
720 * Thinking in noninternationalized USASCII (per the DNS spec),
721 * convert this character to lower case if it's upper case.
722 */
723static int
724mklower(int ch) {
725 if (ch >= 0x41 && ch <= 0x5A)
726 return (ch + 0x20);
727 return (ch);
728}
729
730/*%
731 * Search for the counted-label name in an array of compressed names.
732 *
733 * return:
734 *\li offset from msg if found, or -1.
735 *
736 * notes:
737 *\li dnptrs is the pointer to the first name on the list,
738 *\li not the pointer to the start of the message.
739 */
740static int
741dn_find(const u_char *domain, const u_char *msg,
742 const u_char * const *dnptrs,
743 const u_char * const *lastdnptr)
744{
745 const u_char *dn, *cp, *sp;
746 const u_char * const *cpp;
747 u_int n;
748
749 for (cpp = dnptrs; cpp < lastdnptr; cpp++) {
750 sp = *cpp;
751 /*
752 * terminate search on:
753 * root label
754 * compression pointer
755 * unusable offset
756 */
757 while (*sp != 0 && (*sp & NS_CMPRSFLGS) == 0 &&
758 (sp - msg) < 0x4000) {
759 dn = domain;
760 cp = sp;
761 while ((n = *cp++) != 0) {
762 /*
763 * check for indirection
764 */
765 switch (n & NS_CMPRSFLGS) {
766 case 0: /*%< normal case, n == len */
767 n = labellen(cp - 1); /*%< XXX */
768 if (n != *dn++)
769 goto next;
770
771 for ((void)NULL; n > 0; n--)
772 if (mklower(*dn++) !=
773 mklower(*cp++))
774 goto next;
775 /* Is next root for both ? */
776 if (*dn == '\0' && *cp == '\0')
777 return (sp - msg);
778 if (*dn)
779 continue;
780 goto next;
781 case NS_CMPRSFLGS: /*%< indirection */
782 cp = msg + (((n & 0x3f) << 8) | *cp);
783 break;
784
785 default: /*%< illegal type */
786 __set_errno (EMSGSIZE);
787 return (-1);
788 }
789 }
790 next: ;
791 sp += *sp + 1;
792 }
793 }
794 __set_errno (ENOENT);
795 return (-1);
796}
797
798static int
799decode_bitstring(const unsigned char **cpp, char *dn, const char *eom)
800{
801 const unsigned char *cp = *cpp;
802 char *beg = dn, tc;
803 int b, blen, plen, i;
804
805 if ((blen = (*cp & 0xff)) == 0)
806 blen = 256;
807 plen = (blen + 3) / 4;
808 plen += sizeof("\\[x/]") + (blen > 99 ? 3 : (blen > 9) ? 2 : 1);
809 if (dn + plen >= eom)
810 return(-1);
811
812 cp++;
813 i = SPRINTF((dn, "\\[x"));
814 if (i < 0)
815 return (-1);
816 dn += i;
817 for (b = blen; b > 7; b -= 8, cp++) {
818 i = SPRINTF((dn, "%02x", *cp & 0xff));
819 if (i < 0)
820 return (-1);
821 dn += i;
822 }
823 if (b > 4) {
824 tc = *cp++;
825 i = SPRINTF((dn, "%02x", tc & (0xff << (8 - b))));
826 if (i < 0)
827 return (-1);
828 dn += i;
829 } else if (b > 0) {
830 tc = *cp++;
831 i = SPRINTF((dn, "%1x",
832 ((tc >> 4) & 0x0f) & (0x0f << (4 - b))));
833 if (i < 0)
834 return (-1);
835 dn += i;
836 }
837 i = SPRINTF((dn, "/%d]", blen));
838 if (i < 0)
839 return (-1);
840 dn += i;
841
842 *cpp = cp;
843 return(dn - beg);
844}
845
846static int
847encode_bitstring(const char **bp, const char *end, unsigned char **labelp,
848 unsigned char ** dst, unsigned const char *eom)
849{
850 int afterslash = 0;
851 const char *cp = *bp;
852 unsigned char *tp;
853 char c;
854 const char *beg_blen;
855 char *end_blen = NULL;
856 int value = 0, count = 0, tbcount = 0, blen = 0;
857
858 beg_blen = end_blen = NULL;
859
860 /* a bitstring must contain at least 2 characters */
861 if (end - cp < 2)
862 return(EINVAL);
863
864 /* XXX: currently, only hex strings are supported */
865 if (*cp++ != 'x')
866 return(EINVAL);
867 if (!isxdigit((*cp) & 0xff)) /*%< reject '\[x/BLEN]' */
868 return(EINVAL);
869
870 for (tp = *dst + 1; cp < end && tp < eom; cp++) {
871 switch((c = *cp)) {
872 case ']': /*%< end of the bitstring */
873 if (afterslash) {
874 if (beg_blen == NULL)
875 return(EINVAL);
876 blen = (int)strtol(beg_blen, &end_blen, 10);
877 if (*end_blen != ']')
878 return(EINVAL);
879 }
880 if (count)
881 *tp++ = ((value << 4) & 0xff);
882 cp++; /*%< skip ']' */
883 goto done;
884 case '/':
885 afterslash = 1;
886 break;
887 default:
888 if (afterslash) {
889 if (!isdigit(c&0xff))
890 return(EINVAL);
891 if (beg_blen == NULL) {
892
893 if (c == '0') {
894 /* blen never begings with 0 */
895 return(EINVAL);
896 }
897 beg_blen = cp;
898 }
899 } else {
900 if (!isxdigit(c&0xff))
901 return(EINVAL);
902 value <<= 4;
903 value += digitvalue[(int)c];
904 count += 4;
905 tbcount += 4;
906 if (tbcount > 256)
907 return(EINVAL);
908 if (count == 8) {
909 *tp++ = value;
910 count = 0;
911 }
912 }
913 break;
914 }
915 }
916 done:
917 if (cp >= end || tp >= eom)
918 return(EMSGSIZE);
919
920 /*
921 * bit length validation:
922 * If a <length> is present, the number of digits in the <bit-data>
923 * MUST be just sufficient to contain the number of bits specified
924 * by the <length>. If there are insignificant bits in a final
925 * hexadecimal or octal digit, they MUST be zero.
926 * RFC2673, Section 3.2.
927 */
928 if (blen > 0) {
929 int traillen;
930
931 if (((blen + 3) & ~3) != tbcount)
932 return(EINVAL);
933 traillen = tbcount - blen; /*%< between 0 and 3 */
934 if (((value << (8 - traillen)) & 0xff) != 0)
935 return(EINVAL);
936 }
937 else
938 blen = tbcount;
939 if (blen == 256)
940 blen = 0;
941
942 /* encode the type and the significant bit fields */
943 **labelp = DNS_LABELTYPE_BITSTRING;
944 **dst = blen;
945
946 *bp = cp;
947 *dst = tp;
948
949 return(0);
950}
951
952static int
953labellen(const u_char *lp)
954{
955 int bitlen;
956 u_char l = *lp;
957
958 if ((l & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
959 /* should be avoided by the caller */
960 return(-1);
961 }
962
963 if ((l & NS_CMPRSFLGS) == NS_TYPE_ELT) {
964 if (l == DNS_LABELTYPE_BITSTRING) {
965 if ((bitlen = *(lp + 1)) == 0)
966 bitlen = 256;
967 return((bitlen + 7 ) / 8 + 1);
968 }
969 return(-1); /*%< unknwon ELT */
970 }
971 return(l);
972}
973
974/*! \file */
975