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 #include <sys/types.h>
  68 #include <sys/param.h>
  69 #include <netinet/in.h>
  70 #include <arpa/nameser.h>
  71 #include <ctype.h>
  72 #include <resolv.h>
  73 #include <stdio.h>
  74 #include <string.h>
  75 #include <unistd.h>
  76
  77 /*
  78  * Expand compressed domain name 'comp_dn' to full domain name.
  79  * 'msg' is a pointer to the beginning of the message,
  80  * 'eomorig' points to the first location after the message,
  81  * 'exp_dn' is a pointer to a buffer of size 'length' for the result.
  82  * Return size of compressed name or -1 if there was an error.
  83  */
  84 int
  85 dn_expand(const u_char *msg, const u_char *eom, const u_char *src,
  86           char *dst, int dstsiz)
  87 {
  88         int n = ns_name_uncompress(msg, eom, src, dst, (size_t)dstsiz);
  89
  90         if (n > 0 && dst[0] == '.')
  91                 dst[0] = '\0';
  92         return (n);
  93 }
  94 libresolv_hidden_def (dn_expand)
  95
  96 /*
  97  * Pack domain name 'exp_dn' in presentation form into 'comp_dn'.
  98  * Return the size of the compressed name or -1.
  99  * 'length' is the size of the array pointed to by 'comp_dn'.
 100  */
 101 int
 102 dn_comp(const char *src, u_char *dst, int dstsiz,
 103         u_char **dnptrs, u_char **lastdnptr)
 104 {
 105         return (ns_name_compress(src, dst, (size_t)dstsiz,
 106                                  (const u_char **)dnptrs,
 107                                  (const u_char **)lastdnptr));
 108 }
 109 libresolv_hidden_def (dn_comp)
 110
 111 /*
 112  * Skip over a compressed domain name. Return the size or -1.
 113  */
 114 int
 115 dn_skipname(const u_char *ptr, const u_char *eom) {
 116         const u_char *saveptr = ptr;
 117
 118         if (ns_name_skip(&ptr, eom) == -1)
 119                 return (-1);
 120         return (ptr - saveptr);
 121 }
 122 libresolv_hidden_def (dn_skipname)
 123
 124 /*
 125  * Verify that a domain name uses an acceptable character set.
 126  */
 127
 128 /*
 129  * Note the conspicuous absence of ctype macros in these definitions.  On
 130  * non-ASCII hosts, we can't depend on string literals or ctype macros to
 131  * tell us anything about network-format data.  The rest of the BIND system
 132  * is not careful about this, but for some reason, we're doing it right here.
 133  */
 134 #define PERIOD 0x2e
 135 #define hyphenchar(c) ((c) == 0x2d)
 136 #define underscorechar(c) ((c) == 0x5f)
 137 #define bslashchar(c) ((c) == 0x5c)
 138 #define periodchar(c) ((c) == PERIOD)
 139 #define asterchar(c) ((c) == 0x2a)
 140 #define alphachar(c) (((c) >= 0x41 && (c) <= 0x5a) \
 141                    || ((c) >= 0x61 && (c) <= 0x7a))
 142 #define digitchar(c) ((c) >= 0x30 && (c) <= 0x39)
 143
 144 #define borderchar(c) (alphachar(c) || digitchar(c))
 145 #define middlechar(c) (borderchar(c) || hyphenchar(c) || underscorechar(c))
 146 #define domainchar(c) ((c) > 0x20 && (c) < 0x7f)
 147
 148 int
 149 res_hnok(const char *dn) {
 150         int pch = PERIOD, ch = *dn++;
 151
 152         while (ch != '\0') {
 153                 int nch = *dn++;
 154
 155                 if (periodchar(ch)) {
 156                         (void)NULL;
 157                 } else if (periodchar(pch)) {
 158                         if (!borderchar(ch))
 159                                 return (0);
 160                 } else if (periodchar(nch) || nch == '\0') {
 161                         if (!borderchar(ch))
 162                                 return (0);
 163                 } else {
 164                         if (!middlechar(ch))
 165                                 return (0);
 166                 }
 167                 pch = ch, ch = nch;
 168         }
 169         return (1);
 170 }
 171 libresolv_hidden_def (res_hnok)
 172
 173 /*
 174  * hostname-like (A, MX, WKS) owners can have "*" as their first label
 175  * but must otherwise be as a host name.
 176  */
 177 int
 178 res_ownok(const char *dn) {
 179         if (asterchar(dn[0])) {
 180                 if (periodchar(dn[1]))
 181                         return (res_hnok(dn+2));
 182                 if (dn[1] == '\0')
 183                         return (1);
 184         }
 185         return (res_hnok(dn));
 186 }
 187
 188 /*
 189  * SOA RNAMEs and RP RNAMEs can have any printable character in their first
 190  * label, but the rest of the name has to look like a host name.
 191  */
 192 int
 193 res_mailok(const char *dn) {
 194         int ch, escaped = 0;
 195
 196         /* "." is a valid missing representation */
 197         if (*dn == '\0')
 198                 return (1);
 199
 200         /* otherwise <label>.<hostname> */
 201         while ((ch = *dn++) != '\0') {
 202                 if (!domainchar(ch))
 203                         return (0);
 204                 if (!escaped && periodchar(ch))
 205                         break;
 206                 if (escaped)
 207                         escaped = 0;
 208                 else if (bslashchar(ch))
 209                         escaped = 1;
 210         }
 211         if (periodchar(ch))
 212                 return (res_hnok(dn));
 213         return (0);
 214 }
 215
 216 /*
 217  * This function is quite liberal, since RFC 1034's character sets are only
 218  * recommendations.
 219  */
 220 int
 221 res_dnok(const char *dn) {
 222         int ch;
 223
 224         while ((ch = *dn++) != '\0')
 225                 if (!domainchar(ch))
 226                         return (0);
 227         return (1);
 228 }
 229 libresolv_hidden_def (res_dnok)
 230
 231 /*
 232  * This module must export the following externally-visible symbols:
 233  *      ___putlong
 234  *      ___putshort
 235  *      __getlong
 236  *      __getshort
 237  * Note that one _ comes from C and the others come from us.
 238  */
 239 void __putlong(u_int32_t src, u_char *dst) { ns_put32(src, dst); }
 240 libresolv_hidden_def (__putlong)
 241 void __putshort(u_int16_t src, u_char *dst) { ns_put16(src, dst); }
 242 libresolv_hidden_def (__putshort)
 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 \f
 246
 247 #include <shlib-compat.h>
 248
 249 #if SHLIB_COMPAT(libresolv, GLIBC_2_0, GLIBC_2_2)
 250 # undef dn_expand
 251 weak_alias (__dn_expand, dn_expand);
 252 #endif