resolv/res_comp.c

   1 /*
   2  * Copyright (c) 1985, 1993
   3  *    The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 4. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 /*
  31  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
  32  *
  33  * Permission to use, copy, modify, and distribute this software for any
  34  * purpose with or without fee is hereby granted, provided that the above
  35  * copyright notice and this permission notice appear in all copies, and that
  36  * the name of Digital Equipment Corporation not be used in advertising or
  37  * publicity pertaining to distribution of the document or software without
  38  * specific, written prior permission.
  39  *
  40  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
  41  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
  42  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
  43  * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  44  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  45  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  46  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  47  * SOFTWARE.
  48  */
  49
  50 /*
  51  * Portions Copyright (c) 1996-1999 by Internet Software Consortium.
  52  *
  53  * Permission to use, copy, modify, and distribute this software for any
  54  * purpose with or without fee is hereby granted, provided that the above
  55  * copyright notice and this permission notice appear in all copies.
  56  *
  57  * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
  58  * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
  59  * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
  60  * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  61  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  62  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  63  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  64  * SOFTWARE.
  65  */
  66
  67 #if defined(LIBC_SCCS) && !defined(lint)
  68 static const char sccsid[] = "@(#)res_comp.c    8.1 (Berkeley) 6/4/93";
  69 static const char rcsid[] = "$BINDId: res_comp.c,v 8.15 1999/10/13 16:39:39 vixie Exp $";
  70 #endif /* LIBC_SCCS and not lint */
  71
  72 #include <sys/types.h>
  73 #include <sys/param.h>
  74 #include <netinet/in.h>
  75 #include <arpa/nameser.h>
  76 #include <ctype.h>
  77 #include <resolv.h>
  78 #include <stdio.h>
  79 #include <string.h>
  80 #include <unistd.h>
  81
  82 /*
  83  * Expand compressed domain name 'comp_dn' to full domain name.
  84  * 'msg' is a pointer to the begining of the message,
  85  * 'eomorig' points to the first location after the message,
  86  * 'exp_dn' is a pointer to a buffer of size 'length' for the result.
  87  * Return size of compressed name or -1 if there was an error.
  88  */
  89 int
  90 dn_expand(const u_char *msg, const u_char *eom, const u_char *src,
  91           char *dst, int dstsiz)
  92 {
  93         int n = ns_name_uncompress(msg, eom, src, dst, (size_t)dstsiz);
  94
  95         if (n > 0 && dst[0] == '.')
  96                 dst[0] = '\0';
  97         return (n);
  98 }
  99
 100 /*
 101  * Pack domain name 'exp_dn' in presentation form into 'comp_dn'.
 102  * Return the size of the compressed name or -1.
 103  * 'length' is the size of the array pointed to by 'comp_dn'.
 104  */
 105 int
 106 dn_comp(const char *src, u_char *dst, int dstsiz,
 107         u_char **dnptrs, u_char **lastdnptr)
 108 {
 109         return (ns_name_compress(src, dst, (size_t)dstsiz,
 110                                  (const u_char **)dnptrs,
 111                                  (const u_char **)lastdnptr));
 112 }
 113
 114 /*
 115  * Skip over a compressed domain name. Return the size or -1.
 116  */
 117 int
 118 dn_skipname(const u_char *ptr, const u_char *eom) {
 119         const u_char *saveptr = ptr;
 120
 121         if (ns_name_skip(&ptr, eom) == -1)
 122                 return (-1);
 123         return (ptr - saveptr);
 124 }
 125
 126 /*
 127  * Verify that a domain name uses an acceptable character set.
 128  */
 129
 130 /*
 131  * Note the conspicuous absence of ctype macros in these definitions.  On
 132  * non-ASCII hosts, we can't depend on string literals or ctype macros to
 133  * tell us anything about network-format data.  The rest of the BIND system
 134  * is not careful about this, but for some reason, we're doing it right here.
 135  */
 136 #define PERIOD 0x2e
 137 #define hyphenchar(c) ((c) == 0x2d)
 138 #define underscorechar(c) ((c) == 0x5f)
 139 #define bslashchar(c) ((c) == 0x5c)
 140 #define periodchar(c) ((c) == PERIOD)
 141 #define asterchar(c) ((c) == 0x2a)
 142 #define alphachar(c) (((c) >= 0x41 && (c) <= 0x5a) \
 143                    || ((c) >= 0x61 && (c) <= 0x7a))
 144 #define digitchar(c) ((c) >= 0x30 && (c) <= 0x39)
 145
 146 #define borderchar(c) (alphachar(c) || digitchar(c))
 147 #define middlechar(c) (borderchar(c) || hyphenchar(c) || underscorechar(c))
 148 #define domainchar(c) ((c) > 0x20 && (c) < 0x7f)
 149
 150 int
 151 res_hnok(const char *dn) {
 152         int ppch = '\0', pch = PERIOD, ch = *dn++;
 153
 154         while (ch != '\0') {
 155                 int nch = *dn++;
 156
 157                 if (periodchar(ch)) {
 158                         (void)NULL;
 159                 } else if (periodchar(pch)) {
 160                         if (!borderchar(ch))
 161                                 return (0);
 162                 } else if (periodchar(nch) || nch == '\0') {
 163                         if (!borderchar(ch))
 164                                 return (0);
 165                 } else {
 166                         if (!middlechar(ch))
 167                                 return (0);
 168                 }
 169                 ppch = pch, pch = ch, ch = nch;
 170         }
 171         return (1);
 172 }
 173
 174 /*
 175  * hostname-like (A, MX, WKS) owners can have "*" as their first label
 176  * but must otherwise be as a host name.
 177  */
 178 int
 179 res_ownok(const char *dn) {
 180         if (asterchar(dn[0])) {
 181                 if (periodchar(dn[1]))
 182                         return (res_hnok(dn+2));
 183                 if (dn[1] == '\0')
 184                         return (1);
 185         }
 186         return (res_hnok(dn));
 187 }
 188
 189 /*
 190  * SOA RNAMEs and RP RNAMEs can have any printable character in their first
 191  * label, but the rest of the name has to look like a host name.
 192  */
 193 int
 194 res_mailok(const char *dn) {
 195         int ch, escaped = 0;
 196
 197         /* "." is a valid missing representation */
 198         if (*dn == '\0')
 199                 return (1);
 200
 201         /* otherwise <label>.<hostname> */
 202         while ((ch = *dn++) != '\0') {
 203                 if (!domainchar(ch))
 204                         return (0);
 205                 if (!escaped && periodchar(ch))
 206                         break;
 207                 if (escaped)
 208                         escaped = 0;
 209                 else if (bslashchar(ch))
 210                         escaped = 1;
 211         }
 212         if (periodchar(ch))
 213                 return (res_hnok(dn));
 214         return (0);
 215 }
 216
 217 /*
 218  * This function is quite liberal, since RFC 1034's character sets are only
 219  * recommendations.
 220  */
 221 int
 222 res_dnok(const char *dn) {
 223         int ch;
 224
 225         while ((ch = *dn++) != '\0')
 226                 if (!domainchar(ch))
 227                         return (0);
 228         return (1);
 229 }
 230
 231 #ifdef BIND_4_COMPAT
 232 /*
 233  * This module must export the following externally-visible symbols:
 234  *      ___putlong
 235  *      ___putshort
 236  *      __getlong
 237  *      __getshort
 238  * Note that one _ comes from C and the others come from us.
 239  */
 240 void __putlong(u_int32_t src, u_char *dst) { ns_put32(src, dst); }
 241 void __putshort(u_int16_t src, u_char *dst) { ns_put16(src, dst); }
 242 #ifndef __ultrix__
 243 u_int32_t _getlong(const u_char *src) { return (ns_get32(src)); }
 244 u_int16_t _getshort(const u_char *src) { return (ns_get16(src)); }
 245 #endif /*__ultrix__*/
 246 #endif /*BIND_4_COMPAT*/
 247 \f
 248
 249 #include <shlib-compat.h>
 250
 251 #if SHLIB_COMPAT(libresolv, GLIBC_2_0, GLIBC_2_2)
 252 # undef dn_expand
 253 weak_alias (__dn_expand, dn_expand);
 254 #endif