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  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
  30  *
  31  * Permission to use, copy, modify, and distribute this software for any
  32  * purpose with or without fee is hereby granted, provided that the above
  33  * copyright notice and this permission notice appear in all copies, and that
  34  * the name of Digital Equipment Corporation not be used in advertising or
  35  * publicity pertaining to distribution of the document or software without
  36  * specific, written prior permission.
  37  *
  38  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
  39  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
  40  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
  41  * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  42  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  43  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  44  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  45  * SOFTWARE.
  46  */
  47
  48 /*
  49  * Portions Copyright (c) 1996-1999 by Internet Software Consortium.
  50  *
  51  * Permission to use, copy, modify, and distribute this software for any
  52  * purpose with or without fee is hereby granted, provided that the above
  53  * copyright notice and this permission notice appear in all copies.
  54  *
  55  * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
  56  * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
  57  * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
  58  * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  59  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  60  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  61  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  62  * SOFTWARE.
  63  */
  64
  65 #if defined(LIBC_SCCS) && !defined(lint)
  66 static const char sccsid[] = "@(#)res_comp.c    8.1 (Berkeley) 6/4/93";
  67 static const char rcsid[] = "$Id$";
  68 #endif /* LIBC_SCCS and not lint */
  69
  70 #include <sys/types.h>
  71 #include <sys/param.h>
  72 #include <netinet/in.h>
  73 #include <arpa/nameser.h>
  74
  75 #include <ctype.h>
  76 #include <errno.h>
  77 #include <resolv.h>
  78 #include <stdio.h>
  79
  80 #include <string.h>
  81 #include <unistd.h>
  82
  83
  84 /*
  85  * Expand compressed domain name 'comp_dn' to full domain name.
  86  * 'msg' is a pointer to the begining of the message,
  87  * 'eomorig' points to the first location after the message,
  88  * 'exp_dn' is a pointer to a buffer of size 'length' for the result.
  89  * Return size of compressed name or -1 if there was an error.
  90  */
  91 int
  92 dn_expand(const u_char *msg, const u_char *eom, const u_char *src,
  93           char *dst, int dstsiz)
  94 {
  95         int n = ns_name_uncompress(msg, eom, src, dst, (size_t)dstsiz);
  96
  97         if (n > 0 && dst[0] == '.')
  98                 dst[0] = '\0';
  99         return (n);
 100 }
 101
 102 /*
 103  * Pack domain name 'exp_dn' in presentation form into 'comp_dn'.
 104  * Return the size of the compressed name or -1.
 105  * 'length' is the size of the array pointed to by 'comp_dn'.
 106  */
 107 int
 108 dn_comp(const char *src, u_char *dst, int dstsiz,
 109         u_char **dnptrs, u_char **lastdnptr)
 110 {
 111         return (ns_name_compress(src, dst, (size_t)dstsiz,
 112                                  (const u_char **)dnptrs,
 113                                  (const u_char **)lastdnptr));
 114 }
 115
 116 /*
 117  * Skip over a compressed domain name. Return the size or -1.
 118  */
 119 int
 120 dn_skipname(const u_char *ptr, const u_char *eom) {
 121         const u_char *saveptr = ptr;
 122
 123         if (ns_name_skip(&ptr, eom) == -1)
 124                 return (-1);
 125         return (ptr - saveptr);
 126 }
 127
 128 /*
 129  * Verify that a domain name uses an acceptable character set.
 130  */
 131
 132 /*
 133  * Note the conspicuous absence of ctype macros in these definitions.  On
 134  * non-ASCII hosts, we can't depend on string literals or ctype macros to
 135  * tell us anything about network-format data.  The rest of the BIND system
 136  * is not careful about this, but for some reason, we're doing it right here.
 137  */
 138 #define PERIOD 0x2e
 139 #define hyphenchar(c) ((c) == 0x2d)
 140 #define underscorechar(c) ((c) == 0x5f)
 141 #define bslashchar(c) ((c) == 0x5c)
 142 #define periodchar(c) ((c) == PERIOD)
 143 #define asterchar(c) ((c) == 0x2a)
 144 #define alphachar(c) (((c) >= 0x41 && (c) <= 0x5a) \
 145                    || ((c) >= 0x61 && (c) <= 0x7a))
 146 #define digitchar(c) ((c) >= 0x30 && (c) <= 0x39)
 147
 148 #define borderchar(c) (alphachar(c) || digitchar(c))
 149 #define middlechar(c) (borderchar(c) || hyphenchar(c) || underscorechar(c))
 150 #define domainchar(c) ((c) > 0x20 && (c) < 0x7f)
 151
 152 int
 153 res_hnok(const char *dn) {
 154         int ppch = '\0', pch = PERIOD, ch = *dn++;
 155
 156         while (ch != '\0') {
 157                 int nch = *dn++;
 158
 159                 if (periodchar(ch)) {
 160                         /* NULL */;
 161                 } else if (periodchar(pch)) {
 162                         if (!borderchar(ch))
 163                                 return (0);
 164                 } else if (periodchar(nch) || nch == '\0') {
 165                         if (!borderchar(ch))
 166                                 return (0);
 167                 } else {
 168                         if (!middlechar(ch))
 169                                 return (0);
 170                 }
 171                 ppch = pch, pch = ch, ch = nch;
 172         }
 173         return (1);
 174 }
 175
 176 /*
 177  * hostname-like (A, MX, WKS) owners can have "*" as their first label
 178  * but must otherwise be as a host name.
 179  */
 180 int
 181 res_ownok(const char *dn) {
 182         if (asterchar(dn[0])) {
 183                 if (periodchar(dn[1]))
 184                         return (res_hnok(dn+2));
 185                 if (dn[1] == '\0')
 186                         return (1);
 187         }
 188         return (res_hnok(dn));
 189 }
 190
 191 /*
 192  * SOA RNAMEs and RP RNAMEs can have any printable character in their first
 193  * label, but the rest of the name has to look like a host name.
 194  */
 195 int
 196 res_mailok(const char *dn) {
 197         int ch, escaped = 0;
 198
 199         /* "." is a valid missing representation */
 200         if (*dn == '\0')
 201                 return(1);
 202
 203         /* otherwise <label>.<hostname> */
 204         while ((ch = *dn++) != '\0') {
 205                 if (!domainchar(ch))
 206                         return (0);
 207                 if (!escaped && periodchar(ch))
 208                         break;
 209                 if (escaped)
 210                         escaped = 0;
 211                 else if (bslashchar(ch))
 212                         escaped = 1;
 213         }
 214         if (periodchar(ch))
 215                 return (res_hnok(dn));
 216         return (0);
 217 }
 218
 219 /*
 220  * This function is quite liberal, since RFC 1034's character sets are only
 221  * recommendations.
 222  */
 223 int
 224 res_dnok(const char *dn) {
 225         int ch;
 226
 227         while ((ch = *dn++) != '\0')
 228                 if (!domainchar(ch))
 229                         return (0);
 230         return (1);
 231 }
 232
 233 #ifdef BIND_4_COMPAT
 234 /*
 235  * This module must export the following externally-visible symbols:
 236  *      ___putlong
 237  *      ___putshort
 238  *      __getlong
 239  *      __getshort
 240  * Note that one _ comes from C and the others come from us.
 241  */
 242 void __putlong(u_int32_t src, u_char *dst) { ns_put32(src, dst); }
 243 void __putshort(u_int16_t src, u_char *dst) { ns_put16(src, dst); }
 244 #ifndef __ultrix__
 245 u_int32_t _getlong(const u_char *src) { return (ns_get32(src)); }
 246 u_int16_t _getshort(const u_char *src) { return (ns_get16(src)); }
 247 #endif /*__ultrix__*/
 248 #endif /*BIND_4_COMPAT*/