lib/libc/resolv/res_comp.c

   1 /*
   2  * @(#)res_comp.c       8.1 (Berkeley) 6/4/93
   3  * $Id: res_comp.c,v 1.5 2005/07/28 06:51:50 marka Exp $
   4  */
   5
   6 /*
   7  * Copyright (c) 1985, 1993
   8  *    The Regents of the University of California.  All rights reserved.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 /*
  36  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
  37  *
  38  * Permission to use, copy, modify, and distribute this software for any
  39  * purpose with or without fee is hereby granted, provided that the above
  40  * copyright notice and this permission notice appear in all copies, and that
  41  * the name of Digital Equipment Corporation not be used in advertising or
  42  * publicity pertaining to distribution of the document or software without
  43  * specific, written prior permission.
  44  *
  45  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
  46  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
  47  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
  48  * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  49  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  50  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  51  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  52  * SOFTWARE.
  53  */
  54
  55 /*
  56  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
  57  * Portions Copyright (c) 1996-1999 by Internet Software Consortium.
  58  *
  59  * Permission to use, copy, modify, and distribute this software for any
  60  * purpose with or without fee is hereby granted, provided that the above
  61  * copyright notice and this permission notice appear in all copies.
  62  *
  63  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
  64  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  65  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
  66  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  67  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  68  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  69  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  70  */
  71
  72 #include "port_before.h"
  73 #include <sys/types.h>
  74 #include <sys/param.h>
  75 #include <netinet/in.h>
  76 #include <arpa/nameser.h>
  77 #include <ctype.h>
  78 #include <resolv.h>
  79 #include <stdio.h>
  80 #include <string.h>
  81 #include <unistd.h>
  82 #include "port_after.h"
  83
  84 /*%
  85  * Expand compressed domain name 'src' to full domain name.
  86  *
  87  * \li 'msg' is a pointer to the begining of the message,
  88  * \li 'eom' points to the first location after the message,
  89  * \li 'dst' is a pointer to a buffer of size 'dstsiz' for the result.
  90  * \li Return size of compressed name or -1 if there was an error.
  91  */
  92 int
  93 dn_expand(const u_char *msg, const u_char *eom, const u_char *src,
  94           char *dst, int dstsiz)
  95 {
  96         int n = ns_name_uncompress(msg, eom, src, dst, (size_t)dstsiz);
  97
  98         if (n > 0 && dst[0] == '.')
  99                 dst[0] = '\0';
 100         return (n);
 101 }
 102
 103 /*%
 104  * Pack domain name 'exp_dn' in presentation form into 'comp_dn'.
 105  *
 106  * \li Return the size of the compressed name or -1.
 107  * \li 'length' is the size of the array pointed to by 'comp_dn'.
 108  */
 109 int
 110 dn_comp(const char *src, u_char *dst, int dstsiz,
 111         u_char **dnptrs, u_char **lastdnptr)
 112 {
 113         return (ns_name_compress(src, dst, (size_t)dstsiz,
 114                                  (const u_char **)dnptrs,
 115                                  (const u_char **)lastdnptr));
 116 }
 117
 118 /*%
 119  * Skip over a compressed domain name. Return the size or -1.
 120  */
 121 int
 122 dn_skipname(const u_char *ptr, const u_char *eom) {
 123         const u_char *saveptr = ptr;
 124
 125         if (ns_name_skip(&ptr, eom) == -1)
 126                 return (-1);
 127         return (ptr - saveptr);
 128 }
 129
 130 /*%
 131  * Verify that a domain name uses an acceptable character set.
 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 bslashchar(c) ((c) == 0x5c)
 141 #define periodchar(c) ((c) == PERIOD)
 142 #define asterchar(c) ((c) == 0x2a)
 143 #define alphachar(c) (((c) >= 0x41 && (c) <= 0x5a) \
 144                    || ((c) >= 0x61 && (c) <= 0x7a))
 145 #define digitchar(c) ((c) >= 0x30 && (c) <= 0x39)
 146
 147 #define borderchar(c) (alphachar(c) || digitchar(c))
 148 #define middlechar(c) (borderchar(c) || hyphenchar(c))
 149 #define domainchar(c) ((c) > 0x20 && (c) < 0x7f)
 150
 151 int
 152 res_hnok(const char *dn) {
 153         int pch = PERIOD, ch = *dn++;
 154
 155         while (ch != '\0') {
 156                 int nch = *dn++;
 157
 158                 if (periodchar(ch)) {
 159                         (void)NULL;
 160                 } else if (periodchar(pch)) {
 161                         if (!borderchar(ch))
 162                                 return (0);
 163                 } else if (periodchar(nch) || nch == '\0') {
 164                         if (!borderchar(ch))
 165                                 return (0);
 166                 } else {
 167                         if (!middlechar(ch))
 168                                 return (0);
 169                 }
 170                 pch = ch, ch = nch;
 171         }
 172         return (1);
 173 }
 174
 175 /*%
 176  * hostname-like (A, MX, WKS) owners can have "*" as their first label
 177  * but must otherwise be as a host name.
 178  */
 179 int
 180 res_ownok(const char *dn) {
 181         if (asterchar(dn[0])) {
 182                 if (periodchar(dn[1]))
 183                         return (res_hnok(dn+2));
 184                 if (dn[1] == '\0')
 185                         return (1);
 186         }
 187         return (res_hnok(dn));
 188 }
 189
 190 /*%
 191  * SOA RNAMEs and RP RNAMEs can have any printable character in their first
 192  * label, but the rest of the name has to look like a host name.
 193  */
 194 int
 195 res_mailok(const char *dn) {
 196         int ch, escaped = 0;
 197
 198         /* "." is a valid missing representation */
 199         if (*dn == '\0')
 200                 return (1);
 201
 202         /* otherwise <label>.<hostname> */
 203         while ((ch = *dn++) != '\0') {
 204                 if (!domainchar(ch))
 205                         return (0);
 206                 if (!escaped && periodchar(ch))
 207                         break;
 208                 if (escaped)
 209                         escaped = 0;
 210                 else if (bslashchar(ch))
 211                         escaped = 1;
 212         }
 213         if (periodchar(ch))
 214                 return (res_hnok(dn));
 215         return (0);
 216 }
 217
 218 /*%
 219  * This function is quite liberal, since RFC1034's character sets are only
 220  * recommendations.
 221  */
 222 int
 223 res_dnok(const char *dn) {
 224         int ch;
 225
 226         while ((ch = *dn++) != '\0')
 227                 if (!domainchar(ch))
 228                         return (0);
 229         return (1);
 230 }
 231
 232 #ifdef BIND_4_COMPAT
 233 /*%
 234  * This module must export the following externally-visible symbols:
 235  *      ___putlong
 236  *      ___putshort
 237  *      __getlong
 238  *      __getshort
 239  * Note that one _ comes from C and the others come from us.
 240  */
 241
 242 #ifdef SOLARIS2
 243 #ifdef  __putlong
 244 #undef  __putlong
 245 #endif
 246 #ifdef  __putshort
 247 #undef  __putshort
 248 #endif
 249 #pragma weak    putlong         =       __putlong
 250 #pragma weak    putshort        =       __putshort
 251 #endif /* SOLARIS2 */
 252
 253 void __putlong(u_int32_t src, u_char *dst) { ns_put32(src, dst); }
 254 void __putshort(u_int16_t src, u_char *dst) { ns_put16(src, dst); }
 255 #ifndef __ultrix__
 256 u_int32_t _getlong(const u_char *src) { return (ns_get32(src)); }
 257 u_int16_t _getshort(const u_char *src) { return (ns_get16(src)); }
 258 #endif /*__ultrix__*/
 259 #endif /*BIND_4_COMPAT*/
 260
 261 #ifdef _LIBC
 262 /*
 263  * Weak aliases for applications that use certain private entry points,
 264  * and fail to include <resolv.h>.
 265  */
 266 #undef dn_comp
 267 __weak_reference(__dn_comp, dn_comp);
 268 #undef dn_expand
 269 __weak_reference(__dn_expand, dn_expand);
 270 #endif
 271 /*! \file */