lib/libc/resolv/res_comp.c

   1 /*      $NetBSD: res_comp.c,v 1.12 2012/03/13 21:13:43 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. All advertising materials mentioning features or use of this software
  16  *    must display the following acknowledgement:
  17  *      This product includes software developed by the University of
  18  *      California, Berkeley and its contributors.
  19  * 4. Neither the name of the University nor the names of its contributors
  20  *    may be used to endorse or promote products derived from this software
  21  *    without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  */
  35
  36 /*
  37  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
  38  *
  39  * Permission to use, copy, modify, and distribute this software for any
  40  * purpose with or without fee is hereby granted, provided that the above
  41  * copyright notice and this permission notice appear in all copies, and that
  42  * the name of Digital Equipment Corporation not be used in advertising or
  43  * publicity pertaining to distribution of the document or software without
  44  * specific, written prior permission.
  45  *
  46  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
  47  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
  48  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
  49  * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  50  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  51  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  52  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  53  * SOFTWARE.
  54  */
  55
  56 /*
  57  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
  58  * Portions Copyright (c) 1996-1999 by Internet Software Consortium.
  59  *
  60  * Permission to use, copy, modify, and distribute this software for any
  61  * purpose with or without fee is hereby granted, provided that the above
  62  * copyright notice and this permission notice appear in all copies.
  63  *
  64  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
  65  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  66  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
  67  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  68  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  69  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  70  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  71  */
  72 #include <sys/cdefs.h>
  73 #if defined(LIBC_SCCS) && !defined(lint)
  74 #ifdef notdef
  75 static const char sccsid[] = "@(#)res_comp.c    8.1 (Berkeley) 6/4/93";
  76 static const char rcsid[] = "Id: res_comp.c,v 1.5 2005/07/28 06:51:50 marka Exp";
  77 #else
  78 __RCSID("$NetBSD: res_comp.c,v 1.12 2012/03/13 21:13:43 christos Exp $");
  79 #endif
  80 #endif /* LIBC_SCCS and not lint */
  81
  82 #include "port_before.h"
  83
  84 #include "namespace.h"
  85 #include <sys/types.h>
  86 #include <sys/param.h>
  87 #include <netinet/in.h>
  88 #include <arpa/nameser.h>
  89 #include <assert.h>
  90 #include <ctype.h>
  91 #include <resolv.h>
  92 #include <stdio.h>
  93 #include <string.h>
  94 #include <unistd.h>
  95 #include "port_after.h"
  96
  97 #ifdef __weak_alias
  98 __weak_alias(dn_expand,_dn_expand)
  99 __weak_alias(dn_comp,__dn_comp)
 100 #if defined(__minix)
 101 __weak_alias(dn_skipname,__dn_skipname)
 102 __weak_alias(res_hnok,__res_hnok)
 103 __weak_alias(res_ownok,__res_ownok)
 104 __weak_alias(res_mailok,__res_mailok)
 105 __weak_alias(res_dnok,__res_dnok)
 106 #endif /* defined(__minix) */
 107 #endif
 108
 109 /*%
 110  * Expand compressed domain name 'src' to full domain name.
 111  *
 112  * \li 'msg' is a pointer to the begining of the message,
 113  * \li 'eom' points to the first location after the message,
 114  * \li 'dst' is a pointer to a buffer of size 'dstsiz' for the result.
 115  * \li Return size of compressed name or -1 if there was an error.
 116  */
 117 int
 118 dn_expand(const u_char *msg, const u_char *eom, const u_char *src,
 119           char *dst, int dstsiz)
 120 {
 121         int n = ns_name_uncompress(msg, eom, src, dst, (size_t)dstsiz);
 122
 123         if (n > 0 && dst[0] == '.')
 124                 dst[0] = '\0';
 125         return (n);
 126 }
 127
 128 /*%
 129  * Pack domain name 'exp_dn' in presentation form into 'comp_dn'.
 130  *
 131  * \li Return the size of the compressed name or -1.
 132  * \li 'length' is the size of the array pointed to by 'comp_dn'.
 133  */
 134 int
 135 dn_comp(const char *src, u_char *dst, int dstsiz,
 136         u_char **dnptrs, u_char **lastdnptr)
 137 {
 138         return (ns_name_compress(src, dst, (size_t)dstsiz,
 139                                  (void *)dnptrs,
 140                                  (void *)lastdnptr));
 141 }
 142
 143 /*%
 144  * Skip over a compressed domain name. Return the size or -1.
 145  */
 146 int
 147 dn_skipname(const u_char *ptr, const u_char *eom) {
 148         const u_char *saveptr = ptr;
 149
 150         if (ns_name_skip(&ptr, eom) == -1)
 151                 return (-1);
 152         _DIAGASSERT(__type_fit(int, ptr - saveptr));
 153         return (int)(ptr - saveptr);
 154 }
 155
 156 /*%
 157  * Verify that a domain name uses an acceptable character set.
 158  *
 159  * Note the conspicuous absence of ctype macros in these definitions.  On
 160  * non-ASCII hosts, we can't depend on string literals or ctype macros to
 161  * tell us anything about network-format data.  The rest of the BIND system
 162  * is not careful about this, but for some reason, we're doing it right here.
 163  */
 164 #define PERIOD 0x2e
 165 #define hyphenchar(c) ((c) == 0x2d)
 166 #define bslashchar(c) ((c) == 0x5c)
 167 #define periodchar(c) ((c) == PERIOD)
 168 #define asterchar(c) ((c) == 0x2a)
 169 #define alphachar(c) (((c) >= 0x41 && (c) <= 0x5a) \
 170                    || ((c) >= 0x61 && (c) <= 0x7a))
 171 #define digitchar(c) ((c) >= 0x30 && (c) <= 0x39)
 172
 173 #define borderchar(c) (alphachar(c) || digitchar(c))
 174 #define middlechar(c) (borderchar(c) || hyphenchar(c))
 175 #define domainchar(c) ((c) > 0x20 && (c) < 0x7f)
 176
 177 int
 178 res_hnok(const char *dn) {
 179         int pch = PERIOD, ch = *dn++;
 180
 181         while (ch != '\0') {
 182                 int nch = *dn++;
 183
 184                 if (periodchar(ch)) {
 185                         ;
 186                 } else if (periodchar(pch)) {
 187                         if (!borderchar(ch))
 188                                 return (0);
 189                 } else if (periodchar(nch) || nch == '\0') {
 190                         if (!borderchar(ch))
 191                                 return (0);
 192                 } else {
 193                         if (!middlechar(ch))
 194                                 return (0);
 195                 }
 196                 pch = ch, ch = nch;
 197         }
 198         return (1);
 199 }
 200
 201 /*%
 202  * hostname-like (A, MX, WKS) owners can have "*" as their first label
 203  * but must otherwise be as a host name.
 204  */
 205 int
 206 res_ownok(const char *dn) {
 207         if (asterchar(dn[0])) {
 208                 if (periodchar(dn[1]))
 209                         return (res_hnok(dn+2));
 210                 if (dn[1] == '\0')
 211                         return (1);
 212         }
 213         return (res_hnok(dn));
 214 }
 215
 216 /*%
 217  * SOA RNAMEs and RP RNAMEs can have any printable character in their first
 218  * label, but the rest of the name has to look like a host name.
 219  */
 220 int
 221 res_mailok(const char *dn) {
 222         int ch, escaped = 0;
 223
 224         /* "." is a valid missing representation */
 225         if (*dn == '\0')
 226                 return (1);
 227
 228         /* otherwise <label>.<hostname> */
 229         while ((ch = *dn++) != '\0') {
 230                 if (!domainchar(ch))
 231                         return (0);
 232                 if (!escaped && periodchar(ch))
 233                         break;
 234                 if (escaped)
 235                         escaped = 0;
 236                 else if (bslashchar(ch))
 237                         escaped = 1;
 238         }
 239         if (periodchar(ch))
 240                 return (res_hnok(dn));
 241         return (0);
 242 }
 243
 244 /*%
 245  * This function is quite liberal, since RFC1034's character sets are only
 246  * recommendations.
 247  */
 248 int
 249 res_dnok(const char *dn) {
 250         int ch;
 251
 252         while ((ch = *dn++) != '\0')
 253                 if (!domainchar(ch))
 254                         return (0);
 255         return (1);
 256 }
 257
 258 #ifdef BIND_4_COMPAT
 259 /*%
 260  * This module must export the following externally-visible symbols:
 261  *      ___putlong
 262  *      ___putshort
 263  *      __getlong
 264  *      __getshort
 265  * Note that one _ comes from C and the others come from us.
 266  */
 267
 268 #ifdef SOLARIS2
 269 #ifdef  __putlong
 270 #undef  __putlong
 271 #endif
 272 #ifdef  __putshort
 273 #undef  __putshort
 274 #endif
 275 #pragma weak    putlong         =       __putlong
 276 #pragma weak    putshort        =       __putshort
 277 #endif /* SOLARIS2 */
 278
 279 void __putlong(u_int32_t src, u_char *dst) { ns_put32(src, dst); }
 280 void __putshort(u_int16_t src, u_char *dst) { ns_put16(src, dst); }
 281 #ifndef __ultrix__
 282 u_int32_t _getlong(const u_char *src) { return (ns_get32(src)); }
 283 u_int16_t _getshort(const u_char *src) { return (ns_get16(src)); }
 284 #endif /*__ultrix__*/
 285 #endif /*BIND_4_COMPAT*/
 286
 287 /*! \file */