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hammer2 - Fix bulkfree bugs
[dragonfly.git] / lib / libc / nameser / ns_name.c
blob9d409f3d95368b5d5fe88ed0c577606ab17f3f7a
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 #ifndef lint
19 static const char rcsid[] = "$Id: ns_name.c,v 1.10 2005/04/27 04:56:40 sra Exp $";
20 #endif
21
22 #include "port_before.h"
23
24 #include <sys/types.h>
25
26 #include <netinet/in.h>
27 #include <arpa/nameser.h>
28
29 #include <errno.h>
30 #include <resolv.h>
31 #include <string.h>
32 #include <ctype.h>
33 #include <stdlib.h>
34 #include <limits.h>
35
36 #include "port_after.h"
37
38 #ifdef SPRINTF_CHAR
39 # define SPRINTF(x) strlen(sprintf/**/x)
40 #else
41 # define SPRINTF(x) ((size_t)sprintf x)
42 #endif
43
44 #define NS_TYPE_ELT 0x40 /*%< EDNS0 extended label type */
45 #define DNS_LABELTYPE_BITSTRING 0x41
46
47 /* Data. */
48
49 static const char digits[] = "0123456789";
50
51 static const char digitvalue[256] = {
52 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*16*/
53 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*32*/
54 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*48*/
55 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1, /*64*/
56 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*80*/
57 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*96*/
58 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*112*/
59 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*128*/
60 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
61 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
62 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
63 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
64 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
65 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
66 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
67 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*256*/
68 };
69
70 /* Forward. */
71
72 static int special(int);
73 static int printable(int);
74 static int dn_find(const u_char *, const u_char *,
75 const u_char * const *,
76 const u_char * const *);
77 static int encode_bitsring(const char **, const char *,
78 unsigned char **, unsigned char **,
79 unsigned const char *);
80 static int labellen(const u_char *);
81 static int decode_bitstring(const unsigned char **,
82 char *, const char *);
83
84 /* Public. */
85
86 /*%
87 * Convert an encoded domain name to printable ascii as per RFC1035.
88
89 * return:
90 *\li Number of bytes written to buffer, or -1 (with errno set)
91 *
92 * notes:
93 *\li The root is returned as "."
94 *\li All other domains are returned in non absolute form
95 */
96 int
97 ns_name_ntop(const u_char *src, char *dst, size_t dstsiz)
98 {
99 const u_char *cp;
100 char *dn, *eom;
101 u_char c;
102 u_int n;
103 int l;
104
105 cp = src;
106 dn = dst;
107 eom = dst + dstsiz;
108
109 while ((n = *cp++) != 0) {
110 if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
111 /* Some kind of compression pointer. */
112 errno = EMSGSIZE;
113 return (-1);
114 }
115 if (dn != dst) {
116 if (dn >= eom) {
117 errno = EMSGSIZE;
118 return (-1);
119 }
120 *dn++ = '.';
121 }
122 if ((l = labellen(cp - 1)) < 0) {
123 errno = EMSGSIZE; /*%< XXX */
124 return(-1);
125 }
126 if (dn + l >= eom) {
127 errno = EMSGSIZE;
128 return (-1);
129 }
130 if ((n & NS_CMPRSFLGS) == NS_TYPE_ELT) {
131 int m;
132
133 if (n != DNS_LABELTYPE_BITSTRING) {
134 /* XXX: labellen should reject this case */
135 errno = EINVAL;
136 return(-1);
137 }
138 if ((m = decode_bitstring(&cp, dn, eom)) < 0)
139 {
140 errno = EMSGSIZE;
141 return(-1);
142 }
143 dn += m;
144 continue;
145 }
146 for ((void)NULL; l > 0; l--) {
147 c = *cp++;
148 if (special(c)) {
149 if (dn + 1 >= eom) {
150 errno = EMSGSIZE;
151 return (-1);
152 }
153 *dn++ = '\\';
154 *dn++ = (char)c;
155 } else if (!printable(c)) {
156 if (dn + 3 >= eom) {
157 errno = EMSGSIZE;
158 return (-1);
159 }
160 *dn++ = '\\';
161 *dn++ = digits[c / 100];
162 *dn++ = digits[(c % 100) / 10];
163 *dn++ = digits[c % 10];
164 } else {
165 if (dn >= eom) {
166 errno = EMSGSIZE;
167 return (-1);
168 }
169 *dn++ = (char)c;
170 }
171 }
172 }
173 if (dn == dst) {
174 if (dn >= eom) {
175 errno = EMSGSIZE;
176 return (-1);
177 }
178 *dn++ = '.';
179 }
180 if (dn >= eom) {
181 errno = EMSGSIZE;
182 return (-1);
183 }
184 *dn++ = '\0';
185 return (dn - dst);
186 }
187
188 /*%
189 * Convert a ascii string into an encoded domain name as per RFC1035.
190 *
191 * return:
192 *
193 *\li -1 if it fails
194 *\li 1 if string was fully qualified
195 *\li 0 is string was not fully qualified
196 *
197 * notes:
198 *\li Enforces label and domain length limits.
199 */
200
201 int
202 ns_name_pton(const char *src, u_char *dst, size_t dstsiz)
203 {
204 u_char *label, *bp, *eom;
205 int c, n, escaped, e = 0;
206 char *cp;
207
208 escaped = 0;
209 bp = dst;
210 eom = dst + dstsiz;
211 label = bp++;
212
213 while ((c = *src++) != 0) {
214 if (escaped) {
215 if (c == '[') { /*%< start a bit string label */
216 if ((cp = strchr(src, ']')) == NULL) {
217 errno = EINVAL; /*%< ??? */
218 return(-1);
219 }
220 if ((e = encode_bitsring(&src, cp + 2,
221 &label, &bp, eom))
222 != 0) {
223 errno = e;
224 return(-1);
225 }
226 escaped = 0;
227 label = bp++;
228 if ((c = *src++) == 0)
229 goto done;
230 else if (c != '.') {
231 errno = EINVAL;
232 return(-1);
233 }
234 continue;
235 }
236 else if ((cp = strchr(digits, c)) != NULL) {
237 n = (cp - digits) * 100;
238 if ((c = *src++) == 0 ||
239 (cp = strchr(digits, c)) == NULL) {
240 errno = EMSGSIZE;
241 return (-1);
242 }
243 n += (cp - digits) * 10;
244 if ((c = *src++) == 0 ||
245 (cp = strchr(digits, c)) == NULL) {
246 errno = EMSGSIZE;
247 return (-1);
248 }
249 n += (cp - digits);
250 if (n > 255) {
251 errno = EMSGSIZE;
252 return (-1);
253 }
254 c = n;
255 }
256 escaped = 0;
257 } else if (c == '\\') {
258 escaped = 1;
259 continue;
260 } else if (c == '.') {
261 c = (bp - label - 1);
262 if ((c & NS_CMPRSFLGS) != 0) { /*%< Label too big. */
263 errno = EMSGSIZE;
264 return (-1);
265 }
266 if (label >= eom) {
267 errno = EMSGSIZE;
268 return (-1);
269 }
270 *label = c;
271 /* Fully qualified ? */
272 if (*src == '\0') {
273 if (c != 0) {
274 if (bp >= eom) {
275 errno = EMSGSIZE;
276 return (-1);
277 }
278 *bp++ = '\0';
279 }
280 if ((bp - dst) > MAXCDNAME) {
281 errno = EMSGSIZE;
282 return (-1);
283 }
284 return (1);
285 }
286 if (c == 0 || *src == '.') {
287 errno = EMSGSIZE;
288 return (-1);
289 }
290 label = bp++;
291 continue;
292 }
293 if (bp >= eom) {
294 errno = EMSGSIZE;
295 return (-1);
296 }
297 *bp++ = (u_char)c;
298 }
299 c = (bp - label - 1);
300 if ((c & NS_CMPRSFLGS) != 0) { /*%< Label too big. */
301 errno = EMSGSIZE;
302 return (-1);
303 }
304 done:
305 if (label >= eom) {
306 errno = EMSGSIZE;
307 return (-1);
308 }
309 *label = c;
310 if (c != 0) {
311 if (bp >= eom) {
312 errno = EMSGSIZE;
313 return (-1);
314 }
315 *bp++ = 0;
316 }
317 if ((bp - dst) > MAXCDNAME) { /*%< src too big */
318 errno = EMSGSIZE;
319 return (-1);
320 }
321 return (0);
322 }
323
324 /*%
325 * Convert a network strings labels into all lowercase.
326 *
327 * return:
328 *\li Number of bytes written to buffer, or -1 (with errno set)
329 *
330 * notes:
331 *\li Enforces label and domain length limits.
332 */
333
334 int
335 ns_name_ntol(const u_char *src, u_char *dst, size_t dstsiz)
336 {
337 const u_char *cp;
338 u_char *dn, *eom;
339 u_char c;
340 u_int n;
341 int l;
342
343 cp = src;
344 dn = dst;
345 eom = dst + dstsiz;
346
347 if (dn >= eom) {
348 errno = EMSGSIZE;
349 return (-1);
350 }
351 while ((n = *cp++) != 0) {
352 if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
353 /* Some kind of compression pointer. */
354 errno = EMSGSIZE;
355 return (-1);
356 }
357 *dn++ = n;
358 if ((l = labellen(cp - 1)) < 0) {
359 errno = EMSGSIZE;
360 return (-1);
361 }
362 if (dn + l >= eom) {
363 errno = EMSGSIZE;
364 return (-1);
365 }
366 for ((void)NULL; l > 0; l--) {
367 c = *cp++;
368 if (isupper(c))
369 *dn++ = tolower(c);
370 else
371 *dn++ = c;
372 }
373 }
374 *dn++ = '\0';
375 return (dn - dst);
376 }
377
378 /*%
379 * Unpack a domain name from a message, source may be compressed.
380 *
381 * return:
382 *\li -1 if it fails, or consumed octets if it succeeds.
383 */
384 int
385 ns_name_unpack(const u_char *msg, const u_char *eom, const u_char *src,
386 u_char *dst, size_t dstsiz)
387 {
388 const u_char *srcp, *dstlim;
389 u_char *dstp;
390 int n, len, checked, l;
391
392 len = -1;
393 checked = 0;
394 dstp = dst;
395 srcp = src;
396 dstlim = dst + dstsiz;
397 if (srcp < msg || srcp >= eom) {
398 errno = EMSGSIZE;
399 return (-1);
400 }
401 /* Fetch next label in domain name. */
402 while ((n = *srcp++) != 0) {
403 /* Check for indirection. */
404 switch (n & NS_CMPRSFLGS) {
405 case 0:
406 case NS_TYPE_ELT:
407 /* Limit checks. */
408 if ((l = labellen(srcp - 1)) < 0) {
409 errno = EMSGSIZE;
410 return(-1);
411 }
412 if (dstp + l + 1 >= dstlim || srcp + l >= eom) {
413 errno = EMSGSIZE;
414 return (-1);
415 }
416 checked += l + 1;
417 *dstp++ = n;
418 memcpy(dstp, srcp, l);
419 dstp += l;
420 srcp += l;
421 break;
422
423 case NS_CMPRSFLGS:
424 if (srcp >= eom) {
425 errno = EMSGSIZE;
426 return (-1);
427 }
428 if (len < 0)
429 len = srcp - src + 1;
430 srcp = msg + (((n & 0x3f) << 8) | (*srcp & 0xff));
431 if (srcp < msg || srcp >= eom) { /*%< Out of range. */
432 errno = EMSGSIZE;
433 return (-1);
434 }
435 checked += 2;
436 /*
437 * Check for loops in the compressed name;
438 * if we've looked at the whole message,
439 * there must be a loop.
440 */
441 if (checked >= eom - msg) {
442 errno = EMSGSIZE;
443 return (-1);
444 }
445 break;
446
447 default:
448 errno = EMSGSIZE;
449 return (-1); /*%< flag error */
450 }
451 }
452 *dstp = '\0';
453 if (len < 0)
454 len = srcp - src;
455 return (len);
456 }
457
458 /*%
459 * Pack domain name 'domain' into 'comp_dn'.
460 *
461 * return:
462 *\li Size of the compressed name, or -1.
463 *
464 * notes:
465 *\li 'dnptrs' is an array of pointers to previous compressed names.
466 *\li dnptrs[0] is a pointer to the beginning of the message. The array
467 * ends with NULL.
468 *\li 'lastdnptr' is a pointer to the end of the array pointed to
469 * by 'dnptrs'.
470 *
471 * Side effects:
472 *\li The list of pointers in dnptrs is updated for labels inserted into
473 * the message as we compress the name. If 'dnptr' is NULL, we don't
474 * try to compress names. If 'lastdnptr' is NULL, we don't update the
475 * list.
476 */
477 int
478 ns_name_pack(const u_char *src, u_char *dst, int dstsiz,
479 const u_char **dnptrs, const u_char **lastdnptr)
480 {
481 u_char *dstp;
482 const u_char **cpp, **lpp, *eob, *msg;
483 const u_char *srcp;
484 int n, l, first = 1;
485
486 srcp = src;
487 dstp = dst;
488 eob = dstp + dstsiz;
489 lpp = cpp = NULL;
490 if (dnptrs != NULL) {
491 if ((msg = *dnptrs++) != NULL) {
492 for (cpp = dnptrs; *cpp != NULL; cpp++)
493 (void)NULL;
494 lpp = cpp; /*%< end of list to search */
495 }
496 } else
497 msg = NULL;
498
499 /* make sure the domain we are about to add is legal */
500 l = 0;
501 do {
502 int l0;
503
504 n = *srcp;
505 if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
506 errno = EMSGSIZE;
507 return (-1);
508 }
509 if ((l0 = labellen(srcp)) < 0) {
510 errno = EINVAL;
511 return(-1);
512 }
513 l += l0 + 1;
514 if (l > MAXCDNAME) {
515 errno = EMSGSIZE;
516 return (-1);
517 }
518 srcp += l0 + 1;
519 } while (n != 0);
520
521 /* from here on we need to reset compression pointer array on error */
522 srcp = src;
523 do {
524 /* Look to see if we can use pointers. */
525 n = *srcp;
526 if (n != 0 && msg != NULL) {
527 l = dn_find(srcp, msg, (const u_char * const *)dnptrs,
528 (const u_char * const *)lpp);
529 if (l >= 0) {
530 if (dstp + 1 >= eob) {
531 goto cleanup;
532 }
533 *dstp++ = (l >> 8) | NS_CMPRSFLGS;
534 *dstp++ = l % 256;
535 return (dstp - dst);
536 }
537 /* Not found, save it. */
538 if (lastdnptr != NULL && cpp < lastdnptr - 1 &&
539 (dstp - msg) < 0x4000 && first) {
540 *cpp++ = dstp;
541 *cpp = NULL;
542 first = 0;
543 }
544 }
545 /* copy label to buffer */
546 if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
547 /* Should not happen. */
548 goto cleanup;
549 }
550 n = labellen(srcp);
551 if (dstp + 1 + n >= eob) {
552 goto cleanup;
553 }
554 memcpy(dstp, srcp, n + 1);
555 srcp += n + 1;
556 dstp += n + 1;
557 } while (n != 0);
558
559 if (dstp > eob) {
560 cleanup:
561 if (msg != NULL)
562 *lpp = NULL;
563 errno = EMSGSIZE;
564 return (-1);
565 }
566 return (dstp - dst);
567 }
568
569 /*%
570 * Expand compressed domain name to presentation format.
571 *
572 * return:
573 *\li Number of bytes read out of `src', or -1 (with errno set).
574 *
575 * note:
576 *\li Root domain returns as "." not "".
577 */
578 int
579 ns_name_uncompress(const u_char *msg, const u_char *eom, const u_char *src,
580 char *dst, size_t dstsiz)
581 {
582 u_char tmp[NS_MAXCDNAME];
583 int n;
584
585 if ((n = ns_name_unpack(msg, eom, src, tmp, sizeof tmp)) == -1)
586 return (-1);
587 if (ns_name_ntop(tmp, dst, dstsiz) == -1)
588 return (-1);
589 return (n);
590 }
591
592 /*%
593 * Compress a domain name into wire format, using compression pointers.
594 *
595 * return:
596 *\li Number of bytes consumed in `dst' or -1 (with errno set).
597 *
598 * notes:
599 *\li 'dnptrs' is an array of pointers to previous compressed names.
600 *\li dnptrs[0] is a pointer to the beginning of the message.
601 *\li The list ends with NULL. 'lastdnptr' is a pointer to the end of the
602 * array pointed to by 'dnptrs'. Side effect is to update the list of
603 * pointers for labels inserted into the message as we compress the name.
604 *\li If 'dnptr' is NULL, we don't try to compress names. If 'lastdnptr'
605 * is NULL, we don't update the list.
606 */
607 int
608 ns_name_compress(const char *src, u_char *dst, size_t dstsiz,
609 const u_char **dnptrs, const u_char **lastdnptr)
610 {
611 u_char tmp[NS_MAXCDNAME];
612
613 if (ns_name_pton(src, tmp, sizeof tmp) == -1)
614 return (-1);
615 return (ns_name_pack(tmp, dst, dstsiz, dnptrs, lastdnptr));
616 }
617
618 /*%
619 * Reset dnptrs so that there are no active references to pointers at or
620 * after src.
621 */
622 void
623 ns_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 */
641 int
642 ns_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 errno = EMSGSIZE; /*%< XXX */
658 return(-1);
659 }
660 cp += l;
661 continue;
662 case NS_CMPRSFLGS: /*%< indirection */
663 cp++;
664 break;
665 default: /*%< illegal type */
666 errno = EMSGSIZE;
667 return (-1);
668 }
669 break;
670 }
671 if (cp > eom) {
672 errno = EMSGSIZE;
673 return (-1);
674 }
675 *ptrptr = cp;
676 return (0);
677 }
678
679 /* Private. */
680
681 /*%
682 * Thinking in noninternationalized USASCII (per the DNS spec),
683 * is this characted special ("in need of quoting") ?
684 *
685 * return:
686 *\li boolean.
687 */
688 static int
689 special(int ch) {
690 switch (ch) {
691 case 0x22: /*%< '"' */
692 case 0x2E: /*%< '.' */
693 case 0x3B: /*%< ';' */
694 case 0x5C: /*%< '\\' */
695 case 0x28: /*%< '(' */
696 case 0x29: /*%< ')' */
697 /* Special modifiers in zone files. */
698 case 0x40: /*%< '@' */
699 case 0x24: /*%< '$' */
700 return (1);
701 default:
702 return (0);
703 }
704 }
705
706 /*%
707 * Thinking in noninternationalized USASCII (per the DNS spec),
708 * is this character visible and not a space when printed ?
709 *
710 * return:
711 *\li boolean.
712 */
713 static int
714 printable(int ch) {
715 return (ch > 0x20 && ch < 0x7f);
716 }
717
718 /*%
719 * Thinking in noninternationalized USASCII (per the DNS spec),
720 * convert this character to lower case if it's upper case.
721 */
722 static int
723 mklower(int ch) {
724 if (ch >= 0x41 && ch <= 0x5A)
725 return (ch + 0x20);
726 return (ch);
727 }
728
729 /*%
730 * Search for the counted-label name in an array of compressed names.
731 *
732 * return:
733 *\li offset from msg if found, or -1.
734 *
735 * notes:
736 *\li dnptrs is the pointer to the first name on the list,
737 *\li not the pointer to the start of the message.
738 */
739 static int
740 dn_find(const u_char *domain, const u_char *msg,
741 const u_char * const *dnptrs,
742 const u_char * const *lastdnptr)
743 {
744 const u_char *dn, *cp, *sp;
745 const u_char * const *cpp;
746 u_int n;
747
748 for (cpp = dnptrs; cpp < lastdnptr; cpp++) {
749 sp = *cpp;
750 /*
751 * terminate search on:
752 * root label
753 * compression pointer
754 * unusable offset
755 */
756 while (*sp != 0 && (*sp & NS_CMPRSFLGS) == 0 &&
757 (sp - msg) < 0x4000) {
758 dn = domain;
759 cp = sp;
760 while ((n = *cp++) != 0) {
761 /*
762 * check for indirection
763 */
764 switch (n & NS_CMPRSFLGS) {
765 case 0: /*%< normal case, n == len */
766 n = labellen(cp - 1); /*%< XXX */
767 if (n != *dn++)
768 goto next;
769
770 for ((void)NULL; n > 0; n--)
771 if (mklower(*dn++) !=
772 mklower(*cp++))
773 goto next;
774 /* Is next root for both ? */
775 if (*dn == '\0' && *cp == '\0')
776 return (sp - msg);
777 if (*dn)
778 continue;
779 goto next;
780 case NS_CMPRSFLGS: /*%< indirection */
781 cp = msg + (((n & 0x3f) << 8) | *cp);
782 break;
783
784 default: /*%< illegal type */
785 errno = EMSGSIZE;
786 return (-1);
787 }
788 }
789 next: ;
790 sp += *sp + 1;
791 }
792 }
793 errno = ENOENT;
794 return (-1);
795 }
796
797 static int
798 decode_bitstring(const unsigned char **cpp, char *dn, const char *eom)
799 {
800 const unsigned char *cp = *cpp;
801 char *beg = dn, tc;
802 int b, blen, plen, i;
803
804 if ((blen = (*cp & 0xff)) == 0)
805 blen = 256;
806 plen = (blen + 3) / 4;
807 plen += sizeof("\\[x/]") + (blen > 99 ? 3 : (blen > 9) ? 2 : 1);
808 if (dn + plen >= eom)
809 return(-1);
810
811 cp++;
812 i = SPRINTF((dn, "\\[x"));
813 if (i < 0)
814 return (-1);
815 dn += i;
816 for (b = blen; b > 7; b -= 8, cp++) {
817 i = SPRINTF((dn, "%02x", *cp & 0xff));
818 if (i < 0)
819 return (-1);
820 dn += i;
821 }
822 if (b > 4) {
823 tc = *cp++;
824 i = SPRINTF((dn, "%02x", tc & (0xff << (8 - b))));
825 if (i < 0)
826 return (-1);
827 dn += i;
828 } else if (b > 0) {
829 tc = *cp++;
830 i = SPRINTF((dn, "%1x",
831 ((tc >> 4) & 0x0f) & (0x0f << (4 - b))));
832 if (i < 0)
833 return (-1);
834 dn += i;
835 }
836 i = SPRINTF((dn, "/%d]", blen));
837 if (i < 0)
838 return (-1);
839 dn += i;
840
841 *cpp = cp;
842 return(dn - beg);
843 }
844
845 static int
846 encode_bitsring(const char **bp, const char *end, unsigned char **labelp,
847 unsigned char ** dst, unsigned const char *eom)
848 {
849 int afterslash = 0;
850 const char *cp = *bp;
851 unsigned char *tp;
852 char c;
853 const char *beg_blen;
854 char *end_blen = NULL;
855 int value = 0, count = 0, tbcount = 0, blen = 0;
856
857 beg_blen = end_blen = NULL;
858
859 /* a bitstring must contain at least 2 characters */
860 if (end - cp < 2)
861 return(EINVAL);
862
863 /* XXX: currently, only hex strings are supported */
864 if (*cp++ != 'x')
865 return(EINVAL);
866 if (!isxdigit((*cp) & 0xff)) /*%< reject '\[x/BLEN]' */
867 return(EINVAL);
868
869 for (tp = *dst + 1; cp < end && tp < eom; cp++) {
870 switch((c = *cp)) {
871 case ']': /*%< end of the bitstring */
872 if (afterslash) {
873 if (beg_blen == NULL)
874 return(EINVAL);
875 blen = (int)strtol(beg_blen, &end_blen, 10);
876 if (*end_blen != ']')
877 return(EINVAL);
878 }
879 if (count)
880 *tp++ = ((value << 4) & 0xff);
881 cp++; /*%< skip ']' */
882 goto done;
883 case '/':
884 afterslash = 1;
885 break;
886 default:
887 if (afterslash) {
888 if (!isdigit(c&0xff))
889 return(EINVAL);
890 if (beg_blen == NULL) {
891
892 if (c == '0') {
893 /* blen never begings with 0 */
894 return(EINVAL);
895 }
896 beg_blen = cp;
897 }
898 } else {
899 if (!isxdigit(c&0xff))
900 return(EINVAL);
901 value <<= 4;
902 value += digitvalue[(int)c];
903 count += 4;
904 tbcount += 4;
905 if (tbcount > 256)
906 return(EINVAL);
907 if (count == 8) {
908 *tp++ = value;
909 count = 0;
910 }
911 }
912 break;
913 }
914 }
915 done:
916 if (cp >= end || tp >= eom)
917 return(EMSGSIZE);
918
919 /*
920 * bit length validation:
921 * If a <length> is present, the number of digits in the <bit-data>
922 * MUST be just sufficient to contain the number of bits specified
923 * by the <length>. If there are insignificant bits in a final
924 * hexadecimal or octal digit, they MUST be zero.
925 * RFC2673, Section 3.2.
926 */
927 if (blen > 0) {
928 int traillen;
929
930 if (((blen + 3) & ~3) != tbcount)
931 return(EINVAL);
932 traillen = tbcount - blen; /*%< between 0 and 3 */
933 if (((value << (8 - traillen)) & 0xff) != 0)
934 return(EINVAL);
935 }
936 else
937 blen = tbcount;
938 if (blen == 256)
939 blen = 0;
940
941 /* encode the type and the significant bit fields */
942 **labelp = DNS_LABELTYPE_BITSTRING;
943 **dst = blen;
944
945 *bp = cp;
946 *dst = tp;
947
948 return(0);
949 }
950
951 static int
952 labellen(const u_char *lp)
953 {
954 int bitlen;
955 u_char l = *lp;
956
957 if ((l & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
958 /* should be avoided by the caller */
959 return(-1);
960 }
961
962 if ((l & NS_CMPRSFLGS) == NS_TYPE_ELT) {
963 if (l == DNS_LABELTYPE_BITSTRING) {
964 if ((bitlen = *(lp + 1)) == 0)
965 bitlen = 256;
966 return((bitlen + 7 ) / 8 + 1);
967 }
968 return(-1); /*%< unknwon ELT */
969 }
970 return(l);
971 }
972
973 /*! \file */
DragonFly BSD