lib/libc/resolv/res_comp.c

   1 /*      $NetBSD: res_comp.c,v 1.13 2015/02/24 17:56:20 christos Exp $   */
   2
   3 /*
   4  * Copyright (c) 1985, 1993
   5  *    The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 /*
  33  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
  34  *
  35  * Permission to use, copy, modify, and distribute this software for any
  36  * purpose with or without fee is hereby granted, provided that the above
  37  * copyright notice and this permission notice appear in all copies, and that
  38  * the name of Digital Equipment Corporation not be used in advertising or
  39  * publicity pertaining to distribution of the document or software without
  40  * specific, written prior permission.
  41  *
  42  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
  43  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
  44  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
  45  * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  46  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  47  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  48  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  49  * SOFTWARE.
  50  */
  51
  52 /*
  53  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
  54  * Portions Copyright (c) 1996-1999 by Internet Software Consortium.
  55  *
  56  * Permission to use, copy, modify, and distribute this software for any
  57  * purpose with or without fee is hereby granted, provided that the above
  58  * copyright notice and this permission notice appear in all copies.
  59  *
  60  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
  61  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  62  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
  63  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  64  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  65  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  66  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  67  */
  68 #include <sys/cdefs.h>
  69 #if defined(LIBC_SCCS) && !defined(lint)
  70 #ifdef notdef
  71 static const char sccsid[] = "@(#)res_comp.c    8.1 (Berkeley) 6/4/93";
  72 static const char rcsid[] = "Id: res_comp.c,v 1.5 2005/07/28 06:51:50 marka Exp";
  73 #else
  74 __RCSID("$NetBSD: res_comp.c,v 1.13 2015/02/24 17:56:20 christos Exp $");
  75 #endif
  76 #endif /* LIBC_SCCS and not lint */
  77
  78 #include "port_before.h"
  79
  80 #include "namespace.h"
  81 #include <sys/types.h>
  82 #include <sys/param.h>
  83 #include <netinet/in.h>
  84 #include <arpa/nameser.h>
  85 #include <assert.h>
  86 #include <ctype.h>
  87 #include <resolv.h>
  88 #include <stdio.h>
  89 #include <string.h>
  90 #include <unistd.h>
  91 #include "port_after.h"
  92
  93 #ifdef __weak_alias
  94 __weak_alias(dn_expand,_dn_expand)
  95 __weak_alias(dn_comp,__dn_comp)
  96 #if defined(__minix)
  97 __weak_alias(dn_skipname,__dn_skipname)
  98 __weak_alias(res_hnok,__res_hnok)
  99 __weak_alias(res_ownok,__res_ownok)
 100 __weak_alias(res_mailok,__res_mailok)
 101 __weak_alias(res_dnok,__res_dnok)
 102 #endif /* defined(__minix) */
 103 #endif
 104
 105 /*%
 106  * Expand compressed domain name 'src' to full domain name.
 107  *
 108  * \li 'msg' is a pointer to the begining of the message,
 109  * \li 'eom' points to the first location after the message,
 110  * \li 'dst' is a pointer to a buffer of size 'dstsiz' for the result.
 111  * \li Return size of compressed name or -1 if there was an error.
 112  */
 113 int
 114 dn_expand(const u_char *msg, const u_char *eom, const u_char *src,
 115           char *dst, int dstsiz)
 116 {
 117         int n = ns_name_uncompress(msg, eom, src, dst, (size_t)dstsiz);
 118
 119         if (n > 0 && dst[0] == '.')
 120                 dst[0] = '\0';
 121         return (n);
 122 }
 123
 124 /*%
 125  * Pack domain name 'exp_dn' in presentation form into 'comp_dn'.
 126  *
 127  * \li Return the size of the compressed name or -1.
 128  * \li 'length' is the size of the array pointed to by 'comp_dn'.
 129  */
 130 int
 131 dn_comp(const char *src, u_char *dst, int dstsiz,
 132         u_char **dnptrs, u_char **lastdnptr)
 133 {
 134         return (ns_name_compress(src, dst, (size_t)dstsiz,
 135                                  (void *)dnptrs,
 136                                  (void *)lastdnptr));
 137 }
 138
 139 /*%
 140  * Skip over a compressed domain name. Return the size or -1.
 141  */
 142 int
 143 dn_skipname(const u_char *ptr, const u_char *eom) {
 144         const u_char *saveptr = ptr;
 145
 146         if (ns_name_skip(&ptr, eom) == -1)
 147                 return (-1);
 148         _DIAGASSERT(__type_fit(int, ptr - saveptr));
 149         return (int)(ptr - saveptr);
 150 }
 151
 152 /*%
 153  * Verify that a domain name uses an acceptable character set.
 154  *
 155  * Note the conspicuous absence of ctype macros in these definitions.  On
 156  * non-ASCII hosts, we can't depend on string literals or ctype macros to
 157  * tell us anything about network-format data.  The rest of the BIND system
 158  * is not careful about this, but for some reason, we're doing it right here.
 159  */
 160 #define PERIOD 0x2e
 161 #define hyphenchar(c) ((c) == 0x2d)
 162 #define bslashchar(c) ((c) == 0x5c)
 163 #define periodchar(c) ((c) == PERIOD)
 164 #define asterchar(c) ((c) == 0x2a)
 165 #define alphachar(c) (((c) >= 0x41 && (c) <= 0x5a) \
 166                    || ((c) >= 0x61 && (c) <= 0x7a))
 167 #define digitchar(c) ((c) >= 0x30 && (c) <= 0x39)
 168
 169 #define borderchar(c) (alphachar(c) || digitchar(c))
 170 #define middlechar(c) (borderchar(c) || hyphenchar(c))
 171 #define domainchar(c) ((c) > 0x20 && (c) < 0x7f)
 172
 173 int
 174 res_hnok(const char *dn) {
 175         int pch = PERIOD, ch = *dn++;
 176
 177         while (ch != '\0') {
 178                 int nch = *dn++;
 179
 180                 if (periodchar(ch)) {
 181                         ;
 182                 } else if (periodchar(pch)) {
 183                         if (!borderchar(ch))
 184                                 return (0);
 185                 } else if (periodchar(nch) || nch == '\0') {
 186                         if (!borderchar(ch))
 187                                 return (0);
 188                 } else {
 189                         if (!middlechar(ch))
 190                                 return (0);
 191                 }
 192                 pch = ch, ch = nch;
 193         }
 194         return (1);
 195 }
 196
 197 /*%
 198  * hostname-like (A, MX, WKS) owners can have "*" as their first label
 199  * but must otherwise be as a host name.
 200  */
 201 int
 202 res_ownok(const char *dn) {
 203         if (asterchar(dn[0])) {
 204                 if (periodchar(dn[1]))
 205                         return (res_hnok(dn+2));
 206                 if (dn[1] == '\0')
 207                         return (1);
 208         }
 209         return (res_hnok(dn));
 210 }
 211
 212 /*%
 213  * SOA RNAMEs and RP RNAMEs can have any printable character in their first
 214  * label, but the rest of the name has to look like a host name.
 215  */
 216 int
 217 res_mailok(const char *dn) {
 218         int ch, escaped = 0;
 219
 220         /* "." is a valid missing representation */
 221         if (*dn == '\0')
 222                 return (1);
 223
 224         /* otherwise <label>.<hostname> */
 225         while ((ch = *dn++) != '\0') {
 226                 if (!domainchar(ch))
 227                         return (0);
 228                 if (!escaped && periodchar(ch))
 229                         break;
 230                 if (escaped)
 231                         escaped = 0;
 232                 else if (bslashchar(ch))
 233                         escaped = 1;
 234         }
 235         if (periodchar(ch))
 236                 return (res_hnok(dn));
 237         return (0);
 238 }
 239
 240 /*%
 241  * This function is quite liberal, since RFC1034's character sets are only
 242  * recommendations.
 243  */
 244 int
 245 res_dnok(const char *dn) {
 246         int ch;
 247
 248         while ((ch = *dn++) != '\0')
 249                 if (!domainchar(ch))
 250                         return (0);
 251         return (1);
 252 }
 253
 254 #ifdef BIND_4_COMPAT
 255 /*%
 256  * This module must export the following externally-visible symbols:
 257  *      ___putlong
 258  *      ___putshort
 259  *      __getlong
 260  *      __getshort
 261  * Note that one _ comes from C and the others come from us.
 262  */
 263
 264 #ifdef SOLARIS2
 265 #ifdef  __putlong
 266 #undef  __putlong
 267 #endif
 268 #ifdef  __putshort
 269 #undef  __putshort
 270 #endif
 271 #pragma weak    putlong         =       __putlong
 272 #pragma weak    putshort        =       __putshort
 273 #endif /* SOLARIS2 */
 274
 275 void __putlong(u_int32_t src, u_char *dst) { ns_put32(src, dst); }
 276 void __putshort(u_int16_t src, u_char *dst) { ns_put16(src, dst); }
 277 #ifndef __ultrix__
 278 u_int32_t _getlong(const u_char *src) { return (ns_get32(src)); }
 279 u_int16_t _getshort(const u_char *src) { return (ns_get16(src)); }
 280 #endif /*__ultrix__*/
 281 #endif /*BIND_4_COMPAT*/
 282
 283 /*! \file */