workbench/network/stacks/AROSTCP/bsdsocket/api/res_comp.c

   1 /*
   2  * Copyright (C) 1993 AmiTCP/IP Group, <amitcp-group@hut.fi>
   3  *                    Helsinki University of Technology, Finland.
   4  *                    All rights reserved.
   5  * Copyright (C) 2005 Neil Cafferkey
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful, but
  12  * WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14  * General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  19  * MA 02111-1307, USA.
  20  *
  21  */
  22
  23 /*
  24  * Copyright (c) 1985 Regents of the University of California.
  25  * All rights reserved.
  26  *
  27  * Redistribution and use in source and binary forms, with or without
  28  * modification, are permitted provided that the following conditions
  29  * are met:
  30  * 1. Redistributions of source code must retain the above copyright
  31  *    notice, this list of conditions and the following disclaimer.
  32  * 2. Redistributions in binary form must reproduce the above copyright
  33  *    notice, this list of conditions and the following disclaimer in the
  34  *    documentation and/or other materials provided with the distribution.
  35  * 3. All advertising materials mentioning features or use of this software
  36  *    must display the following acknowledgement:
  37  *      This product includes software developed by the University of
  38  *      California, Berkeley and its contributors.
  39  * 4. Neither the name of the University nor the names of its contributors
  40  *    may be used to endorse or promote products derived from this software
  41  *    without specific prior written permission.
  42  *
  43  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  44  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  45  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  46  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  47  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  48  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  49  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  50  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  51  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  52  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  53  * SUCH DAMAGE.
  54  */
  55
  56 #if defined(LIBC_SCCS) && !defined(lint)
  57 static char sccsid[] = "@(#)res_comp.c  6.22 (Berkeley) 3/19/91";
  58 #endif /* LIBC_SCCS and not lint */
  59
  60 #include <conf.h>
  61
  62 #include <sys/param.h>
  63 #include <arpa/nameser.h>
  64 #include <netinet/in.h>
  65
  66 #include <exec/semaphores.h>
  67
  68 #include <kern/amiga_netdb.h>
  69 #include <api/resolv.h>
  70
  71 static int dn_find(u_char *exp_dn, u_char *msg,
  72                    u_char **dnptrs, u_char **lastdnptr);
  73
  74 /*
  75  * Expand compressed domain name 'comp_dn' to full domain name.
  76  * 'msg' is a pointer to the begining of the message,
  77  * 'eomorig' points to the first location after the message,
  78  * 'exp_dn' is a pointer to a buffer of size 'length' for the result.
  79  * Return size of compressed name or -1 if there was an error.
  80  */
  81 int
  82 dn_expand(const u_char *msg, const u_char *eomorig, const u_char *comp_dn,
  83           u_char *exp_dn, int length)
  84 {
  85         register u_char *cp, *dn;
  86         register int n, c;
  87         u_char *eom;
  88         int len = -1, checked = 0;
  89
  90         dn = exp_dn;
  91         cp = (u_char *)comp_dn;
  92         eom = exp_dn + length;
  93         /*
  94          * fetch next label in domain name
  95          */
  96         while (n = *cp++) {
  97                 /*
  98                  * Check for indirection
  99                  */
 100                 switch (n & INDIR_MASK) {
 101                 case 0:
 102                         if (dn != exp_dn) {
 103                                 if (dn >= eom)
 104                                         return (-1);
 105                                 *dn++ = '.';
 106                         }
 107                         if (dn+n >= eom)
 108                                 return (-1);
 109                         checked += n + 1;
 110                         while (--n >= 0) {
 111                                 if ((c = *cp++) == '.') {
 112                                         if (dn + n + 2 >= eom)
 113                                                 return (-1);
 114                                         *dn++ = '\\';
 115                                 }
 116                                 *dn++ = c;
 117                                 if (cp >= eomorig)      /* out of range */
 118                                         return(-1);
 119                         }
 120                         break;
 121
 122                 case INDIR_MASK:
 123                         if (len < 0)
 124                                 len = cp - comp_dn + 1;
 125                         cp = (u_char *)msg + (((n & 0x3f) << 8) | (*cp & 0xff));
 126                         if (cp < msg || cp >= eomorig)  /* out of range */
 127                                 return(-1);
 128                         checked += 2;
 129                         /*
 130                          * Check for loops in the compressed name;
 131                          * if we've looked at the whole message,
 132                          * there must be a loop.
 133                          */
 134                         if (checked >= eomorig - msg)
 135                                 return (-1);
 136                         break;
 137
 138                 default:
 139                         return (-1);                    /* flag error */
 140                 }
 141         }
 142         *dn = '\0';
 143         if (len < 0)
 144                 len = cp - comp_dn;
 145         return (len);
 146 }
 147
 148 /*
 149  * Compress domain name 'exp_dn' into 'comp_dn'.
 150  * Return the size of the compressed name or -1.
 151  * 'length' is the size of the array pointed to by 'comp_dn'.
 152  * 'dnptrs' is a list of pointers to previous compressed names. dnptrs[0]
 153  * is a pointer to the beginning of the message. The list ends with NULL.
 154  * 'lastdnptr' is a pointer to the end of the arrary pointed to
 155  * by 'dnptrs'. Side effect is to update the list of pointers for
 156  * labels inserted into the message as we compress the name.
 157  * If 'dnptr' is NULL, we don't try to compress names. If 'lastdnptr'
 158  * is NULL, we don't update the list.
 159  */
 160 int
 161 dn_comp(const u_char *exp_dn, u_char *comp_dn, int length,
 162         u_char **dnptrs, u_char **lastdnptr)
 163 {
 164         register u_char *cp, *dn;
 165         register int c, l;
 166         u_char **cpp, **lpp, *sp, *eob;
 167         u_char *msg;
 168
 169         dn = (u_char *)exp_dn;
 170         cp = comp_dn;
 171         eob = cp + length;
 172         if (dnptrs != NULL) {
 173                 if ((msg = *dnptrs++) != NULL) {
 174                         for (cpp = dnptrs; *cpp != NULL; cpp++)
 175                                 ;
 176                         lpp = cpp;      /* end of list to search */
 177                 }
 178         } else
 179                 msg = NULL;
 180         for (c = *dn++; c != '\0'; ) {
 181                 /* look to see if we can use pointers */
 182                 if (msg != NULL) {
 183                         if ((l = dn_find(dn-1, msg, dnptrs, lpp)) >= 0) {
 184                                 if (cp+1 >= eob)
 185                                         return (-1);
 186                                 *cp++ = (l >> 8) | INDIR_MASK;
 187                                 *cp++ = l % 256;
 188                                 return (cp - comp_dn);
 189                         }
 190                         /* not found, save it */
 191                         if (lastdnptr != NULL && cpp < lastdnptr-1) {
 192                                 *cpp++ = cp;
 193                                 *cpp = NULL;
 194                         }
 195                 }
 196                 sp = cp++;      /* save ptr to length byte */
 197                 do {
 198                         if (c == '.') {
 199                                 c = *dn++;
 200                                 break;
 201                         }
 202                         if (c == '\\') {
 203                                 if ((c = *dn++) == '\0')
 204                                         break;
 205                         }
 206                         if (cp >= eob) {
 207                                 if (msg != NULL)
 208                                         *lpp = NULL;
 209                                 return (-1);
 210                         }
 211                         *cp++ = c;
 212                 } while ((c = *dn++) != '\0');
 213                 /* catch trailing '.'s but not '..' */
 214                 if ((l = cp - sp - 1) == 0 && c == '\0') {
 215                         cp--;
 216                         break;
 217                 }
 218                 if (l <= 0 || l > MAXLABEL) {
 219                         if (msg != NULL)
 220                                 *lpp = NULL;
 221                         return (-1);
 222                 }
 223                 *sp = l;
 224         }
 225         if (cp >= eob) {
 226                 if (msg != NULL)
 227                         *lpp = NULL;
 228                 return (-1);
 229         }
 230         *cp++ = '\0';
 231         return (cp - comp_dn);
 232 }
 233
 234 /*
 235  * Skip over a compressed domain name. Return the size or -1.
 236  */
 237 int
 238 __dn_skipname(const u_char *comp_dn, const u_char *eom)
 239 {
 240         register u_char *cp;
 241         register int n;
 242
 243         cp = (u_char *)comp_dn;
 244         while (cp < eom && (n = *cp++)) {
 245                 /*
 246                  * check for indirection
 247                  */
 248                 switch (n & INDIR_MASK) {
 249                 case 0:         /* normal case, n == len */
 250                         cp += n;
 251                         continue;
 252                 default:        /* illegal type */
 253                         return (-1);
 254                 case INDIR_MASK:        /* indirection */
 255                         cp++;
 256                 }
 257                 break;
 258         }
 259         return (cp - comp_dn);
 260 }
 261
 262 /*
 263  * Search for expanded name from a list of previously compressed names.
 264  * Return the offset from msg if found or -1.
 265  * dnptrs is the pointer to the first name on the list,
 266  * not the pointer to the start of the message.
 267  */
 268 static int
 269 dn_find(u_char *exp_dn, u_char *msg,
 270         u_char **dnptrs, u_char **lastdnptr)
 271 {
 272         register u_char *dn, *cp, **cpp;
 273         register int n;
 274         u_char *sp;
 275
 276         for (cpp = dnptrs; cpp < lastdnptr; cpp++) {
 277                 dn = exp_dn;
 278                 sp = cp = *cpp;
 279                 while (n = *cp++) {
 280                         /*
 281                          * check for indirection
 282                          */
 283                         switch (n & INDIR_MASK) {
 284                         case 0:         /* normal case, n == len */
 285                                 while (--n >= 0) {
 286                                         if (*dn == '.')
 287                                                 goto next;
 288                                         if (*dn == '\\')
 289                                                 dn++;
 290                                         if (*dn++ != *cp++)
 291                                                 goto next;
 292                                 }
 293                                 if ((n = *dn++) == '\0' && *cp == '\0')
 294                                         return (sp - msg);
 295                                 if (n == '.')
 296                                         continue;
 297                                 goto next;
 298
 299                         default:        /* illegal type */
 300                                 return (-1);
 301
 302                         case INDIR_MASK:        /* indirection */
 303                                 cp = msg + (((n & 0x3f) << 8) | *cp);
 304                         }
 305                 }
 306                 if (*dn == '\0')
 307                         return (sp - msg);
 308         next:   ;
 309         }
 310         return (-1);
 311 }
 312
 313 /*
 314  * Routines to insert/extract short/long's. Must account for byte
 315  * order and non-alignment problems. This code at least has the
 316  * advantage of being portable.
 317  *
 318  * used by sendmail.
 319  */
 320
 321 u_short
 322 _getshort(u_char *msgp)
 323 {
 324         register u_char *p = (u_char *) msgp;
 325         register u_short u;
 326
 327         u = *p++ << 8;
 328         return ((u_short)(u | *p));
 329 }
 330
 331 u_long
 332 _getlong(u_char *msgp)
 333 {
 334         register u_char *p = (u_char *) msgp;
 335         register u_long u;
 336
 337         u = *p++; u <<= 8;
 338         u |= *p++; u <<= 8;
 339         u |= *p++; u <<= 8;
 340         return (u | *p);
 341 }
 342
 343 void
 344 __putshort(register u_short s, register u_char *msgp)
 345 {
 346         msgp[1] = s;
 347         msgp[0] = s >> 8;
 348 }
 349
 350 void
 351 __putlong(register u_long l, register u_char *msgp)
 352 {
 353         msgp[3] = l;
 354         msgp[2] = (l >>= 8);
 355         msgp[1] = (l >>= 8);
 356         msgp[0] = l >> 8;
 357 }