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.
19 static const char rcsid[] = "$Id: ns_name.c,v 1.11 2009/01/23 19:59:16 each Exp $";
21 #include <sys/cdefs.h>
22 __FBSDID("$FreeBSD$");
24 #include "port_before.h"
26 #include <sys/types.h>
28 #include <netinet/in.h>
29 #include <arpa/nameser.h>
38 #include "port_after.h"
41 # define SPRINTF(x) strlen(sprintf/**/x)
43 # define SPRINTF(x) ((size_t)sprintf x)
46 #define NS_TYPE_ELT 0x40 /*%< EDNS0 extended label type */
47 #define DNS_LABELTYPE_BITSTRING 0x41
51 static const char digits[] = "0123456789";
53 static const char digitvalue[256] = {
54 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*16*/
55 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*32*/
56 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*48*/
57 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1, /*64*/
58 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*80*/
59 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*96*/
60 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*112*/
61 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*128*/
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,
68 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
69 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*256*/
74 static int special(int);
75 static int printable(int);
76 static int dn_find(const u_char *, const u_char *,
77 const u_char * const *,
78 const u_char * const *);
79 static int encode_bitsring(const char **, const char *,
80 unsigned char **, unsigned char **,
81 unsigned const char *);
82 static int labellen(const u_char *);
83 static int decode_bitstring(const unsigned char **,
84 char *, const char *);
89 * Convert an encoded domain name to printable ascii as per RFC1035.
92 *\li Number of bytes written to buffer, or -1 (with errno set)
95 *\li The root is returned as "."
96 *\li All other domains are returned in non absolute form
99 ns_name_ntop(const u_char *src, char *dst, size_t dstsiz)
111 while ((n = *cp++) != 0) {
112 if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
113 /* Some kind of compression pointer. */
124 if ((l = labellen(cp - 1)) < 0) {
125 errno = EMSGSIZE; /*%< XXX */
132 if ((n & NS_CMPRSFLGS) == NS_TYPE_ELT) {
135 if (n != DNS_LABELTYPE_BITSTRING) {
136 /* XXX: labellen should reject this case */
140 if ((m = decode_bitstring(&cp, dn, eom)) < 0)
148 for ((void)NULL; l > 0; l--) {
157 } else if (!printable(c)) {
163 *dn++ = digits[c / 100];
164 *dn++ = digits[(c % 100) / 10];
165 *dn++ = digits[c % 10];
191 * Convert a ascii string into an encoded domain name as per RFC1035.
196 *\li 1 if string was fully qualified
197 *\li 0 is string was not fully qualified
200 *\li Enforces label and domain length limits.
203 ns_name_pton(const char *src, u_char *dst, size_t dstsiz) {
204 return (ns_name_pton2(src, dst, dstsiz, NULL));
208 * ns_name_pton2(src, dst, dstsiz, *dstlen)
209 * Convert a ascii string into an encoded domain name as per RFC1035.
212 * 1 if string was fully qualified
213 * 0 is string was not fully qualified
215 * fills in *dstlen (if non-NULL)
217 * Enforces label and domain length limits.
220 ns_name_pton2(const char *src, u_char *dst, size_t dstsiz, size_t *dstlen) {
221 u_char *label, *bp, *eom;
222 int c, n, escaped, e = 0;
230 while ((c = *src++) != 0) {
232 if (c == '[') { /*%< start a bit string label */
233 if ((cp = strchr(src, ']')) == NULL) {
234 errno = EINVAL; /*%< ??? */
237 if ((e = encode_bitsring(&src, cp + 2,
245 if ((c = *src++) == 0)
253 else if ((cp = strchr(digits, c)) != NULL) {
254 n = (cp - digits) * 100;
255 if ((c = *src++) == 0 ||
256 (cp = strchr(digits, c)) == NULL) {
260 n += (cp - digits) * 10;
261 if ((c = *src++) == 0 ||
262 (cp = strchr(digits, c)) == NULL) {
274 } else if (c == '\\') {
277 } else if (c == '.') {
278 c = (bp - label - 1);
279 if ((c & NS_CMPRSFLGS) != 0) { /*%< Label too big. */
288 /* Fully qualified ? */
297 if ((bp - dst) > MAXCDNAME) {
302 *dstlen = (bp - dst);
305 if (c == 0 || *src == '.') {
318 c = (bp - label - 1);
319 if ((c & NS_CMPRSFLGS) != 0) { /*%< Label too big. */
336 if ((bp - dst) > MAXCDNAME) { /*%< src too big */
341 *dstlen = (bp - dst);
346 * Convert a network strings labels into all lowercase.
349 *\li Number of bytes written to buffer, or -1 (with errno set)
352 *\li Enforces label and domain length limits.
356 ns_name_ntol(const u_char *src, u_char *dst, size_t dstsiz)
372 while ((n = *cp++) != 0) {
373 if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
374 /* Some kind of compression pointer. */
379 if ((l = labellen(cp - 1)) < 0) {
387 for ((void)NULL; l > 0; l--) {
389 if (isascii(c) && isupper(c))
400 * Unpack a domain name from a message, source may be compressed.
403 *\li -1 if it fails, or consumed octets if it succeeds.
406 ns_name_unpack(const u_char *msg, const u_char *eom, const u_char *src,
407 u_char *dst, size_t dstsiz)
409 return (ns_name_unpack2(msg, eom, src, dst, dstsiz, NULL));
413 * ns_name_unpack2(msg, eom, src, dst, dstsiz, *dstlen)
414 * Unpack a domain name from a message, source may be compressed.
416 * -1 if it fails, or consumed octets if it succeeds.
418 * fills in *dstlen (if non-NULL).
421 ns_name_unpack2(const u_char *msg, const u_char *eom, const u_char *src,
422 u_char *dst, size_t dstsiz, size_t *dstlen)
424 const u_char *srcp, *dstlim;
426 int n, len, checked, l;
432 dstlim = dst + dstsiz;
433 if (srcp < msg || srcp >= eom) {
437 /* Fetch next label in domain name. */
438 while ((n = *srcp++) != 0) {
439 /* Check for indirection. */
440 switch (n & NS_CMPRSFLGS) {
444 if ((l = labellen(srcp - 1)) < 0) {
448 if (dstp + l + 1 >= dstlim || srcp + l >= eom) {
454 memcpy(dstp, srcp, l);
465 len = srcp - src + 1;
466 l = ((n & 0x3f) << 8) | (*srcp & 0xff);
467 if (l >= eom - msg) { /*%< Out of range. */
474 * Check for loops in the compressed name;
475 * if we've looked at the whole message,
476 * there must be a loop.
478 if (checked >= eom - msg) {
486 return (-1); /*%< flag error */
491 *dstlen = dstp - dst;
498 * Pack domain name 'domain' into 'comp_dn'.
501 *\li Size of the compressed name, or -1.
504 *\li 'dnptrs' is an array of pointers to previous compressed names.
505 *\li dnptrs[0] is a pointer to the beginning of the message. The array
507 *\li 'lastdnptr' is a pointer to the end of the array pointed to
511 *\li The list of pointers in dnptrs is updated for labels inserted into
512 * the message as we compress the name. If 'dnptr' is NULL, we don't
513 * try to compress names. If 'lastdnptr' is NULL, we don't update the
517 ns_name_pack(const u_char *src, u_char *dst, int dstsiz,
518 const u_char **dnptrs, const u_char **lastdnptr)
521 const u_char **cpp, **lpp, *eob, *msg;
529 if (dnptrs != NULL) {
530 if ((msg = *dnptrs++) != NULL) {
531 for (cpp = dnptrs; *cpp != NULL; cpp++)
533 lpp = cpp; /*%< end of list to search */
538 /* make sure the domain we are about to add is legal */
544 if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
548 if ((l0 = labellen(srcp)) < 0) {
560 /* from here on we need to reset compression pointer array on error */
563 /* Look to see if we can use pointers. */
565 if (n != 0 && msg != NULL) {
566 l = dn_find(srcp, msg, (const u_char * const *)dnptrs,
567 (const u_char * const *)lpp);
569 if (dstp + 1 >= eob) {
572 *dstp++ = (l >> 8) | NS_CMPRSFLGS;
576 /* Not found, save it. */
577 if (lastdnptr != NULL && cpp < lastdnptr - 1 &&
578 (dstp - msg) < 0x4000 && first) {
584 /* copy label to buffer */
585 if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
586 /* Should not happen. */
590 if (dstp + 1 + n >= eob) {
593 memcpy(dstp, srcp, n + 1);
609 * Expand compressed domain name to presentation format.
612 *\li Number of bytes read out of `src', or -1 (with errno set).
615 *\li Root domain returns as "." not "".
618 ns_name_uncompress(const u_char *msg, const u_char *eom, const u_char *src,
619 char *dst, size_t dstsiz)
621 u_char tmp[NS_MAXCDNAME];
624 if ((n = ns_name_unpack(msg, eom, src, tmp, sizeof tmp)) == -1)
626 if (ns_name_ntop(tmp, dst, dstsiz) == -1)
632 * Compress a domain name into wire format, using compression pointers.
635 *\li Number of bytes consumed in `dst' or -1 (with errno set).
638 *\li 'dnptrs' is an array of pointers to previous compressed names.
639 *\li dnptrs[0] is a pointer to the beginning of the message.
640 *\li The list ends with NULL. 'lastdnptr' is a pointer to the end of the
641 * array pointed to by 'dnptrs'. Side effect is to update the list of
642 * pointers for labels inserted into the message as we compress the name.
643 *\li If 'dnptr' is NULL, we don't try to compress names. If 'lastdnptr'
644 * is NULL, we don't update the list.
647 ns_name_compress(const char *src, u_char *dst, size_t dstsiz,
648 const u_char **dnptrs, const u_char **lastdnptr)
650 u_char tmp[NS_MAXCDNAME];
652 if (ns_name_pton(src, tmp, sizeof tmp) == -1)
654 return (ns_name_pack(tmp, dst, dstsiz, dnptrs, lastdnptr));
658 * Reset dnptrs so that there are no active references to pointers at or
662 ns_name_rollback(const u_char *src, const u_char **dnptrs,
663 const u_char **lastdnptr)
665 while (dnptrs < lastdnptr && *dnptrs != NULL) {
666 if (*dnptrs >= src) {
675 * Advance *ptrptr to skip over the compressed name it points at.
678 *\li 0 on success, -1 (with errno set) on failure.
681 ns_name_skip(const u_char **ptrptr, const u_char *eom)
688 while (cp < eom && (n = *cp++) != 0) {
689 /* Check for indirection. */
690 switch (n & NS_CMPRSFLGS) {
691 case 0: /*%< normal case, n == len */
694 case NS_TYPE_ELT: /*%< EDNS0 extended label */
695 if ((l = labellen(cp - 1)) < 0) {
696 errno = EMSGSIZE; /*%< XXX */
701 case NS_CMPRSFLGS: /*%< indirection */
704 default: /*%< illegal type */
718 /* Find the number of octets an nname takes up, including the root label.
719 * (This is basically ns_name_skip() without compression-pointer support.)
720 * ((NOTE: can only return zero if passed-in namesiz argument is zero.))
723 ns_name_length(ns_nname_ct nname, size_t namesiz) {
724 ns_nname_ct orig = nname;
727 while (namesiz-- > 0 && (n = *nname++) != 0) {
728 if ((n & NS_CMPRSFLGS) != 0) {
739 return (nname - orig);
742 /* Compare two nname's for equality. Return -1 on error (setting errno).
745 ns_name_eq(ns_nname_ct a, size_t as, ns_nname_ct b, size_t bs) {
746 ns_nname_ct ae = a + as, be = b + bs;
749 while (ac = *a, bc = *b, ac != 0 && bc != 0) {
750 if ((ac & NS_CMPRSFLGS) != 0 || (bc & NS_CMPRSFLGS) != 0) {
754 if (a + ac >= ae || b + bc >= be) {
758 if (ac != bc || strncasecmp((const char *) ++a,
759 (const char *) ++b, ac) != 0)
763 return (ac == 0 && bc == 0);
766 /* Is domain "A" owned by (at or below) domain "B"?
769 ns_name_owned(ns_namemap_ct a, int an, ns_namemap_ct b, int bn) {
770 /* If A is shorter, it cannot be owned by B. */
774 /* If they are unequal before the length of the shorter, A cannot... */
776 if (a->len != b->len ||
777 strncasecmp((const char *) a->base,
778 (const char *) b->base, a->len) != 0)
784 /* A might be longer or not, but either way, B owns it. */
788 /* Build an array of <base,len> tuples from an nname, top-down order.
789 * Return the number of tuples (labels) thus discovered.
792 ns_name_map(ns_nname_ct nname, size_t namelen, ns_namemap_t map, int mapsize) {
801 /* Extra data follows name? */
809 /* Compression pointer? */
810 if ((n & NS_CMPRSFLGS) != 0) {
815 /* Label too long? */
821 /* Recurse to get rest of name done first. */
822 l = ns_name_map(nname + n, namelen - n, map, mapsize);
826 /* Too many labels? */
828 errno = ENAMETOOLONG;
832 /* We're on our way back up-stack, store current map data. */
838 /* Count the labels in a domain name. Root counts, so COM. has two. This
839 * is to make the result comparable to the result of ns_name_map().
842 ns_name_labels(ns_nname_ct nname, size_t namesiz) {
846 while (namesiz-- > 0 && (n = *nname++) != 0) {
847 if ((n & NS_CMPRSFLGS) != 0) {
865 * Thinking in noninternationalized USASCII (per the DNS spec),
866 * is this characted special ("in need of quoting") ?
874 case 0x22: /*%< '"' */
875 case 0x2E: /*%< '.' */
876 case 0x3B: /*%< ';' */
877 case 0x5C: /*%< '\\' */
878 case 0x28: /*%< '(' */
879 case 0x29: /*%< ')' */
880 /* Special modifiers in zone files. */
881 case 0x40: /*%< '@' */
882 case 0x24: /*%< '$' */
890 * Thinking in noninternationalized USASCII (per the DNS spec),
891 * is this character visible and not a space when printed ?
898 return (ch > 0x20 && ch < 0x7f);
902 * Thinking in noninternationalized USASCII (per the DNS spec),
903 * convert this character to lower case if it's upper case.
907 if (ch >= 0x41 && ch <= 0x5A)
913 * Search for the counted-label name in an array of compressed names.
916 *\li offset from msg if found, or -1.
919 *\li dnptrs is the pointer to the first name on the list,
920 *\li not the pointer to the start of the message.
923 dn_find(const u_char *domain, const u_char *msg,
924 const u_char * const *dnptrs,
925 const u_char * const *lastdnptr)
927 const u_char *dn, *cp, *sp;
928 const u_char * const *cpp;
931 for (cpp = dnptrs; cpp < lastdnptr; cpp++) {
934 * terminate search on:
936 * compression pointer
939 while (*sp != 0 && (*sp & NS_CMPRSFLGS) == 0 &&
940 (sp - msg) < 0x4000) {
943 while ((n = *cp++) != 0) {
945 * check for indirection
947 switch (n & NS_CMPRSFLGS) {
948 case 0: /*%< normal case, n == len */
949 n = labellen(cp - 1); /*%< XXX */
953 for ((void)NULL; n > 0; n--)
954 if (mklower(*dn++) !=
957 /* Is next root for both ? */
958 if (*dn == '\0' && *cp == '\0')
963 case NS_CMPRSFLGS: /*%< indirection */
964 cp = msg + (((n & 0x3f) << 8) | *cp);
967 default: /*%< illegal type */
981 decode_bitstring(const unsigned char **cpp, char *dn, const char *eom)
983 const unsigned char *cp = *cpp;
985 int b, blen, plen, i;
987 if ((blen = (*cp & 0xff)) == 0)
989 plen = (blen + 3) / 4;
990 plen += sizeof("\\[x/]") + (blen > 99 ? 3 : (blen > 9) ? 2 : 1);
991 if (dn + plen >= eom)
995 i = SPRINTF((dn, "\\[x"));
999 for (b = blen; b > 7; b -= 8, cp++) {
1000 i = SPRINTF((dn, "%02x", *cp & 0xff));
1007 i = SPRINTF((dn, "%02x", tc & (0xff << (8 - b))));
1013 i = SPRINTF((dn, "%1x",
1014 ((tc >> 4) & 0x0f) & (0x0f << (4 - b))));
1019 i = SPRINTF((dn, "/%d]", blen));
1029 encode_bitsring(const char **bp, const char *end, unsigned char **labelp,
1030 unsigned char ** dst, unsigned const char *eom)
1033 const char *cp = *bp;
1036 const char *beg_blen;
1037 char *end_blen = NULL;
1038 int value = 0, count = 0, tbcount = 0, blen = 0;
1040 beg_blen = end_blen = NULL;
1042 /* a bitstring must contain at least 2 characters */
1046 /* XXX: currently, only hex strings are supported */
1049 if (!isxdigit((*cp) & 0xff)) /*%< reject '\[x/BLEN]' */
1052 for (tp = *dst + 1; cp < end && tp < eom; cp++) {
1054 case ']': /*%< end of the bitstring */
1056 if (beg_blen == NULL)
1058 blen = (int)strtol(beg_blen, &end_blen, 10);
1059 if (*end_blen != ']')
1063 *tp++ = ((value << 4) & 0xff);
1064 cp++; /*%< skip ']' */
1071 if (!isdigit(c&0xff))
1073 if (beg_blen == NULL) {
1076 /* blen never begings with 0 */
1082 if (!isxdigit(c&0xff))
1085 value += digitvalue[(int)c];
1099 if (cp >= end || tp >= eom)
1103 * bit length validation:
1104 * If a <length> is present, the number of digits in the <bit-data>
1105 * MUST be just sufficient to contain the number of bits specified
1106 * by the <length>. If there are insignificant bits in a final
1107 * hexadecimal or octal digit, they MUST be zero.
1108 * RFC2673, Section 3.2.
1113 if (((blen + 3) & ~3) != tbcount)
1115 traillen = tbcount - blen; /*%< between 0 and 3 */
1116 if (((value << (8 - traillen)) & 0xff) != 0)
1124 /* encode the type and the significant bit fields */
1125 **labelp = DNS_LABELTYPE_BITSTRING;
1135 labellen(const u_char *lp)
1140 if ((l & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
1141 /* should be avoided by the caller */
1145 if ((l & NS_CMPRSFLGS) == NS_TYPE_ELT) {
1146 if (l == DNS_LABELTYPE_BITSTRING) {
1147 if ((bitlen = *(lp + 1)) == 0)
1149 return ((bitlen + 7 ) / 8 + 1);
1151 return (-1); /*%< unknwon ELT */