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 libresolv_hidden_def (dn_expand)
 100
 101 /*
 102  * Pack domain name 'exp_dn' in presentation form into 'comp_dn'.
 103  * Return the size of the compressed name or -1.
 104  * 'length' is the size of the array pointed to by 'comp_dn'.
 105  */
 106 int
 107 dn_comp(const char *src, u_char *dst, int dstsiz,
 108         u_char **dnptrs, u_char **lastdnptr)
 109 {
 110         return (ns_name_compress(src, dst, (size_t)dstsiz,
 111                                  (const u_char **)dnptrs,
 112                                  (const u_char **)lastdnptr));
 113 }
 114 libresolv_hidden_def (dn_comp)
 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 libresolv_hidden_def (dn_skipname)
 128
 129 /*
 130  * Verify that a domain name uses an acceptable character set.
 131  */
 132
 133 /*
 134  * Note the conspicuous absence of ctype macros in these definitions.  On
 135  * non-ASCII hosts, we can't depend on string literals or ctype macros to
 136  * tell us anything about network-format data.  The rest of the BIND system
 137  * is not careful about this, but for some reason, we're doing it right here.
 138  */
 139 #define PERIOD 0x2e
 140 #define hyphenchar(c) ((c) == 0x2d)
 141 #define underscorechar(c) ((c) == 0x5f)
 142 #define bslashchar(c) ((c) == 0x5c)
 143 #define periodchar(c) ((c) == PERIOD)
 144 #define asterchar(c) ((c) == 0x2a)
 145 #define alphachar(c) (((c) >= 0x41 && (c) <= 0x5a) \
 146                    || ((c) >= 0x61 && (c) <= 0x7a))
 147 #define digitchar(c) ((c) >= 0x30 && (c) <= 0x39)
 148
 149 #define borderchar(c) (alphachar(c) || digitchar(c))
 150 #define middlechar(c) (borderchar(c) || hyphenchar(c) || underscorechar(c))
 151 #define domainchar(c) ((c) > 0x20 && (c) < 0x7f)
 152
 153 int
 154 res_hnok(const char *dn) {
 155         int pch = PERIOD, ch = *dn++;
 156
 157         while (ch != '\0') {
 158                 int nch = *dn++;
 159
 160                 if (periodchar(ch)) {
 161                         (void)NULL;
 162                 } else if (periodchar(pch)) {
 163                         if (!borderchar(ch))
 164                                 return (0);
 165                 } else if (periodchar(nch) || nch == '\0') {
 166                         if (!borderchar(ch))
 167                                 return (0);
 168                 } else {
 169                         if (!middlechar(ch))
 170                                 return (0);
 171                 }
 172                 pch = ch, ch = nch;
 173         }
 174         return (1);
 175 }
 176 libresolv_hidden_def (res_hnok)
 177
 178 /*
 179  * hostname-like (A, MX, WKS) owners can have "*" as their first label
 180  * but must otherwise be as a host name.
 181  */
 182 int
 183 res_ownok(const char *dn) {
 184         if (asterchar(dn[0])) {
 185                 if (periodchar(dn[1]))
 186                         return (res_hnok(dn+2));
 187                 if (dn[1] == '\0')
 188                         return (1);
 189         }
 190         return (res_hnok(dn));
 191 }
 192
 193 /*
 194  * SOA RNAMEs and RP RNAMEs can have any printable character in their first
 195  * label, but the rest of the name has to look like a host name.
 196  */
 197 int
 198 res_mailok(const char *dn) {
 199         int ch, escaped = 0;
 200
 201         /* "." is a valid missing representation */
 202         if (*dn == '\0')
 203                 return (1);
 204
 205         /* otherwise <label>.<hostname> */
 206         while ((ch = *dn++) != '\0') {
 207                 if (!domainchar(ch))
 208                         return (0);
 209                 if (!escaped && periodchar(ch))
 210                         break;
 211                 if (escaped)
 212                         escaped = 0;
 213                 else if (bslashchar(ch))
 214                         escaped = 1;
 215         }
 216         if (periodchar(ch))
 217                 return (res_hnok(dn));
 218         return (0);
 219 }
 220
 221 /*
 222  * This function is quite liberal, since RFC 1034's character sets are only
 223  * recommendations.
 224  */
 225 int
 226 res_dnok(const char *dn) {
 227         int ch;
 228
 229         while ((ch = *dn++) != '\0')
 230                 if (!domainchar(ch))
 231                         return (0);
 232         return (1);
 233 }
 234 libresolv_hidden_def (res_dnok)
 235
 236 #ifdef BIND_4_COMPAT
 237 /*
 238  * This module must export the following externally-visible symbols:
 239  *      ___putlong
 240  *      ___putshort
 241  *      __getlong
 242  *      __getshort
 243  * Note that one _ comes from C and the others come from us.
 244  */
 245 void __putlong(u_int32_t src, u_char *dst) { ns_put32(src, dst); }
 246 libresolv_hidden_def (__putlong)
 247 void __putshort(u_int16_t src, u_char *dst) { ns_put16(src, dst); }
 248 libresolv_hidden_def (__putshort)
 249 #ifndef __ultrix__
 250 u_int32_t _getlong(const u_char *src) { return (ns_get32(src)); }
 251 u_int16_t _getshort(const u_char *src) { return (ns_get16(src)); }
 252 #endif /*__ultrix__*/
 253 #endif /*BIND_4_COMPAT*/
 254 \f
 255
 256 #include <shlib-compat.h>
 257
 258 #if SHLIB_COMPAT(libresolv, GLIBC_2_0, GLIBC_2_2)
 259 # undef dn_expand
 260 weak_alias (__dn_expand, dn_expand);
 261 #endif