minires/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  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 /*
  35  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
  36  *
  37  * Permission to use, copy, modify, and distribute this software for any
  38  * purpose with or without fee is hereby granted, provided that the above
  39  * copyright notice and this permission notice appear in all copies, and that
  40  * the name of Digital Equipment Corporation not be used in advertising or
  41  * publicity pertaining to distribution of the document or software without
  42  * specific, written prior permission.
  43  *
  44  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
  45  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
  46  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
  47  * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  48  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  49  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  50  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  51  * SOFTWARE.
  52  */
  53
  54 /*
  55  * Portions Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
  56  * Portions Copyright (c) 1996-2003 by Internet Software Consortium
  57  *
  58  * Permission to use, copy, modify, and distribute this software for any
  59  * purpose with or without fee is hereby granted, provided that the above
  60  * copyright notice and this permission notice appear in all copies.
  61  *
  62  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
  63  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  64  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
  65  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  66  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  67  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  68  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  69  *
  70  *   Internet Systems Consortium, Inc.
  71  *   950 Charter Street
  72  *   Redwood City, CA 94063
  73  *   <info@isc.org>
  74  *   http://www.isc.org/
  75  */
  76
  77 #if defined(LIBC_SCCS) && !defined(lint)
  78 static const char sccsid[] = "@(#)res_comp.c    8.1 (Berkeley) 6/4/93";
  79 static const char rcsid[] = "$Id: res_comp.c,v 1.3 2005/03/17 20:15:18 dhankins Exp $";
  80 #endif /* LIBC_SCCS and not lint */
  81
  82 #include <sys/types.h>
  83 #include <sys/param.h>
  84 #include <netinet/in.h>
  85 #include <ctype.h>
  86 #include <stdio.h>
  87 #include <string.h>
  88 #include <unistd.h>
  89 #include <sys/socket.h>
  90
  91 #include "minires/minires.h"
  92 #include "arpa/nameser.h"
  93
  94 /*
  95  * Expand compressed domain name 'comp_dn' to full domain name.
  96  * 'msg' is a pointer to the begining of the message,
  97  * 'eomorig' points to the first location after the message,
  98  * 'exp_dn' is a pointer to a buffer of size 'length' for the result.
  99  * Return size of compressed name or -1 if there was an error.
 100  */
 101 int
 102 dn_expand(const u_char *msg, const u_char *eom, const u_char *src,
 103           char *dst, unsigned dstsiz)
 104 {
 105         int n = ns_name_uncompress(msg, eom, src, dst, (size_t)dstsiz);
 106
 107         if (n > 0 && dst[0] == '.')
 108                 dst[0] = '\0';
 109         return (n);
 110 }
 111
 112 /*
 113  * Pack domain name 'exp_dn' in presentation form into 'comp_dn'.
 114  * Return the size of the compressed name or -1.
 115  * 'length' is the size of the array pointed to by 'comp_dn'.
 116  */
 117 int
 118 dn_comp(const char *src, u_char *dst, unsigned dstsiz,
 119         u_char **dnptrs, u_char **lastdnptr)
 120 {
 121         return (ns_name_compress(src, dst, (size_t)dstsiz,
 122                                  (const u_char **)dnptrs,
 123                                  (const u_char **)lastdnptr));
 124 }
 125
 126 /*
 127  * Skip over a compressed domain name. Return the size or -1.
 128  */
 129 int
 130 dn_skipname(const u_char *ptr, const u_char *eom) {
 131         const u_char *saveptr = ptr;
 132
 133         if (ns_name_skip(&ptr, eom) == -1)
 134                 return (-1);
 135         return (ptr - saveptr);
 136 }
 137
 138 /*
 139  * Verify that a domain name uses an acceptable character set.
 140  */
 141
 142 #if 0
 143 /*
 144  * Note the conspicuous absence of ctype macros in these definitions.  On
 145  * non-ASCII hosts, we can't depend on string literals or ctype macros to
 146  * tell us anything about network-format data.  The rest of the BIND system
 147  * is not careful about this, but for some reason, we're doing it right here.
 148  */
 149 #define PERIOD 0x2e
 150 #define hyphenchar(c) ((c) == 0x2d)
 151 #define bslashchar(c) ((c) == 0x5c)
 152 #define periodchar(c) ((c) == PERIOD)
 153 #define asterchar(c) ((c) == 0x2a)
 154 #define alphachar(c) (((c) >= 0x41 && (c) <= 0x5a) \
 155                    || ((c) >= 0x61 && (c) <= 0x7a))
 156 #define digitchar(c) ((c) >= 0x30 && (c) <= 0x39)
 157
 158 #define borderchar(c) (alphachar(c) || digitchar(c))
 159 #define middlechar(c) (borderchar(c) || hyphenchar(c))
 160 #define domainchar(c) ((c) > 0x20 && (c) < 0x7f)
 161
 162 int
 163 res_hnok(const char *dn) {
 164         int ppch = '\0', pch = PERIOD, ch = *dn++;
 165
 166         while (ch != '\0') {
 167                 int nch = *dn++;
 168
 169                 if (periodchar(ch)) {
 170                         (void)NULL;
 171                 } else if (periodchar(pch)) {
 172                         if (!borderchar(ch))
 173                                 return (0);
 174                 } else if (periodchar(nch) || nch == '\0') {
 175                         if (!borderchar(ch))
 176                                 return (0);
 177                 } else {
 178                         if (!middlechar(ch))
 179                                 return (0);
 180                 }
 181                 ppch = pch, pch = ch, ch = nch;
 182         }
 183         return (1);
 184 }
 185
 186 /*
 187  * hostname-like (A, MX, WKS) owners can have "*" as their first label
 188  * but must otherwise be as a host name.
 189  */
 190 int
 191 res_ownok(const char *dn) {
 192         if (asterchar(dn[0])) {
 193                 if (periodchar(dn[1]))
 194                         return (res_hnok(dn+2));
 195                 if (dn[1] == '\0')
 196                         return (1);
 197         }
 198         return (res_hnok(dn));
 199 }
 200
 201 /*
 202  * SOA RNAMEs and RP RNAMEs can have any printable character in their first
 203  * label, but the rest of the name has to look like a host name.
 204  */
 205 int
 206 res_mailok(const char *dn) {
 207         int ch, escaped = 0;
 208
 209         /* "." is a valid missing representation */
 210         if (*dn == '\0')
 211                 return (1);
 212
 213         /* otherwise <label>.<hostname> */
 214         while ((ch = *dn++) != '\0') {
 215                 if (!domainchar(ch))
 216                         return (0);
 217                 if (!escaped && periodchar(ch))
 218                         break;
 219                 if (escaped)
 220                         escaped = 0;
 221                 else if (bslashchar(ch))
 222                         escaped = 1;
 223         }
 224         if (periodchar(ch))
 225                 return (res_hnok(dn));
 226         return (0);
 227 }
 228
 229 /*
 230  * This function is quite liberal, since RFC 1034's character sets are only
 231  * recommendations.
 232  */
 233 int
 234 res_dnok(const char *dn) {
 235         int ch;
 236
 237         while ((ch = *dn++) != '\0')
 238                 if (!domainchar(ch))
 239                         return (0);
 240         return (1);
 241 }
 242 #endif