2 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
3 * Copyright (c) 1996,1999 by Internet Software Consortium.
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.
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.
17 * $Id: ns_name.c,v 1.10 2005/04/27 04:56:40 sra Exp $
20 #include "port_before.h"
22 #include <sys/types.h>
24 #include <netinet/in.h>
25 #include <arpa/nameser.h>
34 #include "port_after.h"
37 # define SPRINTF(x) strlen(sprintf/**/x)
39 # define SPRINTF(x) ((size_t)sprintf x)
42 #define NS_TYPE_ELT 0x40 /*%< EDNS0 extended label type */
43 #define DNS_LABELTYPE_BITSTRING 0x41
47 static const char digits[] = "0123456789";
49 static const char digitvalue[256] = {
50 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*16*/
51 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*32*/
52 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*48*/
53 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1, /*64*/
54 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*80*/
55 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*96*/
56 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*112*/
57 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*128*/
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,
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, /*256*/
70 static int special(int);
71 static int printable(int);
72 static int dn_find(const u_char *, const u_char *,
73 const u_char * const *,
74 const u_char * const *);
75 static int encode_bitsring(const char **, const char *,
76 unsigned char **, unsigned char **,
77 unsigned const char *);
78 static int labellen(const u_char *);
79 static int decode_bitstring(const unsigned char **,
80 char *, const char *);
85 * Convert an encoded domain name to printable ascii as per RFC1035.
88 *\li Number of bytes written to buffer, or -1 (with errno set)
91 *\li The root is returned as "."
92 *\li All other domains are returned in non absolute form
95 ns_name_ntop(const u_char *src, char *dst, size_t dstsiz)
107 while ((n = *cp++) != 0) {
108 if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
109 /* Some kind of compression pointer. */
120 if ((l = labellen(cp - 1)) < 0) {
121 errno = EMSGSIZE; /*%< XXX */
128 if ((n & NS_CMPRSFLGS) == NS_TYPE_ELT) {
131 if (n != DNS_LABELTYPE_BITSTRING) {
132 /* XXX: labellen should reject this case */
136 if ((m = decode_bitstring(&cp, dn, eom)) < 0)
144 for ((void)NULL; l > 0; l--) {
153 } else if (!printable(c)) {
159 *dn++ = digits[c / 100];
160 *dn++ = digits[(c % 100) / 10];
161 *dn++ = digits[c % 10];
187 * Convert a ascii string into an encoded domain name as per RFC1035.
192 *\li 1 if string was fully qualified
193 *\li 0 is string was not fully qualified
196 *\li Enforces label and domain length limits.
200 ns_name_pton(const char *src, u_char *dst, size_t dstsiz)
202 u_char *label, *bp, *eom;
203 int c, n, escaped, e = 0;
211 while ((c = *src++) != 0) {
213 if (c == '[') { /*%< start a bit string label */
214 if ((cp = strchr(src, ']')) == NULL) {
215 errno = EINVAL; /*%< ??? */
218 if ((e = encode_bitsring(&src, cp + 2,
226 if ((c = *src++) == 0)
234 else if ((cp = strchr(digits, c)) != NULL) {
235 n = (cp - digits) * 100;
236 if ((c = *src++) == 0 ||
237 (cp = strchr(digits, c)) == NULL) {
241 n += (cp - digits) * 10;
242 if ((c = *src++) == 0 ||
243 (cp = strchr(digits, c)) == NULL) {
255 } else if (c == '\\') {
258 } else if (c == '.') {
259 c = (bp - label - 1);
260 if ((c & NS_CMPRSFLGS) != 0) { /*%< Label too big. */
269 /* Fully qualified ? */
278 if ((bp - dst) > MAXCDNAME) {
284 if (c == 0 || *src == '.') {
297 c = (bp - label - 1);
298 if ((c & NS_CMPRSFLGS) != 0) { /*%< Label too big. */
315 if ((bp - dst) > MAXCDNAME) { /*%< src too big */
323 * Convert a network strings labels into all lowercase.
326 *\li Number of bytes written to buffer, or -1 (with errno set)
329 *\li Enforces label and domain length limits.
333 ns_name_ntol(const u_char *src, u_char *dst, size_t dstsiz)
349 while ((n = *cp++) != 0) {
350 if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
351 /* Some kind of compression pointer. */
356 if ((l = labellen(cp - 1)) < 0) {
364 for ((void)NULL; l > 0; l--) {
377 * Unpack a domain name from a message, source may be compressed.
380 *\li -1 if it fails, or consumed octets if it succeeds.
383 ns_name_unpack(const u_char *msg, const u_char *eom, const u_char *src,
384 u_char *dst, size_t dstsiz)
386 const u_char *srcp, *dstlim;
388 int n, len, checked, l;
394 dstlim = dst + dstsiz;
395 if (srcp < msg || srcp >= eom) {
399 /* Fetch next label in domain name. */
400 while ((n = *srcp++) != 0) {
401 /* Check for indirection. */
402 switch (n & NS_CMPRSFLGS) {
406 if ((l = labellen(srcp - 1)) < 0) {
410 if (dstp + l + 1 >= dstlim || srcp + l >= eom) {
416 memcpy(dstp, srcp, l);
427 len = srcp - src + 1;
428 srcp = msg + (((n & 0x3f) << 8) | (*srcp & 0xff));
429 if (srcp < msg || srcp >= eom) { /*%< Out of range. */
435 * Check for loops in the compressed name;
436 * if we've looked at the whole message,
437 * there must be a loop.
439 if (checked >= eom - msg) {
447 return (-1); /*%< flag error */
457 * Pack domain name 'domain' into 'comp_dn'.
460 *\li Size of the compressed name, or -1.
463 *\li 'dnptrs' is an array of pointers to previous compressed names.
464 *\li dnptrs[0] is a pointer to the beginning of the message. The array
466 *\li 'lastdnptr' is a pointer to the end of the array pointed to
470 *\li The list of pointers in dnptrs is updated for labels inserted into
471 * the message as we compress the name. If 'dnptr' is NULL, we don't
472 * try to compress names. If 'lastdnptr' is NULL, we don't update the
476 ns_name_pack(const u_char *src, u_char *dst, int dstsiz,
477 const u_char **dnptrs, const u_char **lastdnptr)
480 const u_char **cpp, **lpp, *eob, *msg;
488 if (dnptrs != NULL) {
489 if ((msg = *dnptrs++) != NULL) {
490 for (cpp = dnptrs; *cpp != NULL; cpp++)
492 lpp = cpp; /*%< end of list to search */
497 /* make sure the domain we are about to add is legal */
503 if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
507 if ((l0 = labellen(srcp)) < 0) {
519 /* from here on we need to reset compression pointer array on error */
522 /* Look to see if we can use pointers. */
524 if (n != 0 && msg != NULL) {
525 l = dn_find(srcp, msg, (const u_char * const *)dnptrs,
526 (const u_char * const *)lpp);
528 if (dstp + 1 >= eob) {
531 *dstp++ = (l >> 8) | NS_CMPRSFLGS;
535 /* Not found, save it. */
536 if (lastdnptr != NULL && cpp < lastdnptr - 1 &&
537 (dstp - msg) < 0x4000 && first) {
543 /* copy label to buffer */
544 if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
545 /* Should not happen. */
549 if (dstp + 1 + n >= eob) {
552 memcpy(dstp, srcp, n + 1);
568 * Expand compressed domain name to presentation format.
571 *\li Number of bytes read out of `src', or -1 (with errno set).
574 *\li Root domain returns as "." not "".
577 ns_name_uncompress(const u_char *msg, const u_char *eom, const u_char *src,
578 char *dst, size_t dstsiz)
580 u_char tmp[NS_MAXCDNAME];
583 if ((n = ns_name_unpack(msg, eom, src, tmp, sizeof tmp)) == -1)
585 if (ns_name_ntop(tmp, dst, dstsiz) == -1)
591 * Compress a domain name into wire format, using compression pointers.
594 *\li Number of bytes consumed in `dst' or -1 (with errno set).
597 *\li 'dnptrs' is an array of pointers to previous compressed names.
598 *\li dnptrs[0] is a pointer to the beginning of the message.
599 *\li The list ends with NULL. 'lastdnptr' is a pointer to the end of the
600 * array pointed to by 'dnptrs'. Side effect is to update the list of
601 * pointers for labels inserted into the message as we compress the name.
602 *\li If 'dnptr' is NULL, we don't try to compress names. If 'lastdnptr'
603 * is NULL, we don't update the list.
606 ns_name_compress(const char *src, u_char *dst, size_t dstsiz,
607 const u_char **dnptrs, const u_char **lastdnptr)
609 u_char tmp[NS_MAXCDNAME];
611 if (ns_name_pton(src, tmp, sizeof tmp) == -1)
613 return (ns_name_pack(tmp, dst, dstsiz, dnptrs, lastdnptr));
617 * Reset dnptrs so that there are no active references to pointers at or
621 ns_name_rollback(const u_char *src, const u_char **dnptrs,
622 const u_char **lastdnptr)
624 while (dnptrs < lastdnptr && *dnptrs != NULL) {
625 if (*dnptrs >= src) {
634 * Advance *ptrptr to skip over the compressed name it points at.
637 *\li 0 on success, -1 (with errno set) on failure.
640 ns_name_skip(const u_char **ptrptr, const u_char *eom)
647 while (cp < eom && (n = *cp++) != 0) {
648 /* Check for indirection. */
649 switch (n & NS_CMPRSFLGS) {
650 case 0: /*%< normal case, n == len */
653 case NS_TYPE_ELT: /*%< EDNS0 extended label */
654 if ((l = labellen(cp - 1)) < 0) {
655 errno = EMSGSIZE; /*%< XXX */
660 case NS_CMPRSFLGS: /*%< indirection */
663 default: /*%< illegal type */
680 * Thinking in noninternationalized USASCII (per the DNS spec),
681 * is this characted special ("in need of quoting") ?
689 case 0x22: /*%< '"' */
690 case 0x2E: /*%< '.' */
691 case 0x3B: /*%< ';' */
692 case 0x5C: /*%< '\\' */
693 case 0x28: /*%< '(' */
694 case 0x29: /*%< ')' */
695 /* Special modifiers in zone files. */
696 case 0x40: /*%< '@' */
697 case 0x24: /*%< '$' */
705 * Thinking in noninternationalized USASCII (per the DNS spec),
706 * is this character visible and not a space when printed ?
713 return (ch > 0x20 && ch < 0x7f);
717 * Thinking in noninternationalized USASCII (per the DNS spec),
718 * convert this character to lower case if it's upper case.
722 if (ch >= 0x41 && ch <= 0x5A)
728 * Search for the counted-label name in an array of compressed names.
731 *\li offset from msg if found, or -1.
734 *\li dnptrs is the pointer to the first name on the list,
735 *\li not the pointer to the start of the message.
738 dn_find(const u_char *domain, const u_char *msg,
739 const u_char * const *dnptrs,
740 const u_char * const *lastdnptr)
742 const u_char *dn, *cp, *sp;
743 const u_char * const *cpp;
746 for (cpp = dnptrs; cpp < lastdnptr; cpp++) {
749 * terminate search on:
751 * compression pointer
754 while (*sp != 0 && (*sp & NS_CMPRSFLGS) == 0 &&
755 (sp - msg) < 0x4000) {
758 while ((n = *cp++) != 0) {
760 * check for indirection
762 switch (n & NS_CMPRSFLGS) {
763 case 0: /*%< normal case, n == len */
764 n = labellen(cp - 1); /*%< XXX */
768 for ((void)NULL; n > 0; n--)
769 if (mklower(*dn++) !=
772 /* Is next root for both ? */
773 if (*dn == '\0' && *cp == '\0')
778 case NS_CMPRSFLGS: /*%< indirection */
779 cp = msg + (((n & 0x3f) << 8) | *cp);
782 default: /*%< illegal type */
796 decode_bitstring(const unsigned char **cpp, char *dn, const char *eom)
798 const unsigned char *cp = *cpp;
800 int b, blen, plen, i;
802 if ((blen = (*cp & 0xff)) == 0)
804 plen = (blen + 3) / 4;
805 plen += sizeof("\\[x/]") + (blen > 99 ? 3 : (blen > 9) ? 2 : 1);
806 if (dn + plen >= eom)
810 i = SPRINTF((dn, "\\[x"));
814 for (b = blen; b > 7; b -= 8, cp++) {
815 i = SPRINTF((dn, "%02x", *cp & 0xff));
822 i = SPRINTF((dn, "%02x", tc & (0xff << (8 - b))));
828 i = SPRINTF((dn, "%1x",
829 ((tc >> 4) & 0x0f) & (0x0f << (4 - b))));
834 i = SPRINTF((dn, "/%d]", blen));
844 encode_bitsring(const char **bp, const char *end, unsigned char **labelp,
845 unsigned char ** dst, unsigned const char *eom)
848 const char *cp = *bp;
851 const char *beg_blen;
852 char *end_blen = NULL;
853 int value = 0, count = 0, tbcount = 0, blen = 0;
855 beg_blen = end_blen = NULL;
857 /* a bitstring must contain at least 2 characters */
861 /* XXX: currently, only hex strings are supported */
864 if (!isxdigit((*cp) & 0xff)) /*%< reject '\[x/BLEN]' */
867 for (tp = *dst + 1; cp < end && tp < eom; cp++) {
869 case ']': /*%< end of the bitstring */
871 if (beg_blen == NULL)
873 blen = (int)strtol(beg_blen, &end_blen, 10);
874 if (*end_blen != ']')
878 *tp++ = ((value << 4) & 0xff);
879 cp++; /*%< skip ']' */
886 if (!isdigit(c&0xff))
888 if (beg_blen == NULL) {
891 /* blen never begings with 0 */
897 if (!isxdigit(c&0xff))
900 value += digitvalue[(int)c];
914 if (cp >= end || tp >= eom)
918 * bit length validation:
919 * If a <length> is present, the number of digits in the <bit-data>
920 * MUST be just sufficient to contain the number of bits specified
921 * by the <length>. If there are insignificant bits in a final
922 * hexadecimal or octal digit, they MUST be zero.
923 * RFC2673, Section 3.2.
928 if (((blen + 3) & ~3) != tbcount)
930 traillen = tbcount - blen; /*%< between 0 and 3 */
931 if (((value << (8 - traillen)) & 0xff) != 0)
939 /* encode the type and the significant bit fields */
940 **labelp = DNS_LABELTYPE_BITSTRING;
950 labellen(const u_char *lp)
955 if ((l & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
956 /* should be avoided by the caller */
960 if ((l & NS_CMPRSFLGS) == NS_TYPE_ELT) {
961 if (l == DNS_LABELTYPE_BITSTRING) {
962 if ((bitlen = *(lp + 1)) == 0)
964 return((bitlen + 7 ) / 8 + 1);
966 return(-1); /*%< unknwon ELT */