dns.subproj/res_init.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Portions Copyright (c) 1999 Apple Computer, Inc.  All Rights
   7  * Reserved.  This file contains Original Code and/or Modifications of
   8  * Original Code as defined in and that are subject to the Apple Public
   9  * Source License Version 1.1 (the "License").  You may not use this file
  10  * except in compliance with the License.  Please obtain a copy of the
  11  * License at http://www.apple.com/publicsource and read it before using
  12  * this file.
  13  *
  14  * The Original Code and all software distributed under the License are
  15  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  16  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  17  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE OR NON- INFRINGEMENT.  Please see the
  19  * License for the specific language governing rights and limitations
  20  * under the License.
  21  *
  22  * @APPLE_LICENSE_HEADER_END@
  23  */
  24 /*
  25  * ++Copyright++ 1985, 1989, 1993
  26  * -
  27  * Copyright (c) 1985, 1989, 1993
  28  *    The Regents of the University of California.  All rights reserved.
  29  *
  30  * Redistribution and use in source and binary forms, with or without
  31  * modification, are permitted provided that the following conditions
  32  * are met:
  33  * 1. Redistributions of source code must retain the above copyright
  34  *    notice, this list of conditions and the following disclaimer.
  35  * 2. Redistributions in binary form must reproduce the above copyright
  36  *    notice, this list of conditions and the following disclaimer in the
  37  *    documentation and/or other materials provided with the distribution.
  38  * 3. All advertising materials mentioning features or use of this software
  39  *    must display the following acknowledgement:
  40  *      This product includes software developed by the University of
  41  *      California, Berkeley and its contributors.
  42  * 4. Neither the name of the University nor the names of its contributors
  43  *    may be used to endorse or promote products derived from this software
  44  *    without specific prior written permission.
  45  *
  46  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  47  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  48  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  49  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  50  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  51  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  52  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  53  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  54  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  55  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  56  * SUCH DAMAGE.
  57  * -
  58  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
  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, and that
  63  * the name of Digital Equipment Corporation not be used in advertising or
  64  * publicity pertaining to distribution of the document or software without
  65  * specific, written prior permission.
  66  *
  67  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
  68  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
  69  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
  70  * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  71  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  72  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  73  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  74  * SOFTWARE.
  75  * -
  76  * --Copyright--
  77  */
  78
  79 #if defined(LIBC_SCCS) && !defined(lint)
  80 static char sccsid[] = "@(#)res_init.c  8.1 (Berkeley) 6/7/93";
  81 static char rcsid[] = "$Id: res_init.c,v 1.8 2003/02/18 17:29:24 majka Exp $";
  82 #endif /* LIBC_SCCS and not lint */
  83
  84 #include <sys/param.h>
  85 #include <sys/socket.h>
  86 #include <sys/time.h>
  87 #include <netinet/in.h>
  88 #include <arpa/inet.h>
  89 #include <arpa/nameser8_compat.h>
  90
  91 #include <stdio.h>
  92 #include <ctype.h>
  93 #include <resolv8_compat.h>
  94 #if defined(BSD) && (BSD >= 199103)
  95 # include <unistd.h>
  96 # include <stdlib.h>
  97 # include <string.h>
  98 #else
  99 # include "portability.h"
 100 #endif
 101
 102 #if defined(USE_OPTIONS_H)
 103 # include "options.h"
 104 #endif
 105
 106 static void res_setoptions __P((char *, char *));
 107
 108 #ifdef RESOLVSORT
 109 static const char sort_mask[] = "/&";
 110 #define ISSORTMASK(ch) (strchr(sort_mask, ch) != NULL)
 111 static u_int32_t net_mask __P((struct in_addr));
 112 #endif
 113
 114 #if !defined(isascii)   /* XXX - could be a function */
 115 # define isascii(c) (!(c & 0200))
 116 #endif
 117
 118 /*
 119  * Resolver state default settings.
 120  */
 121
 122 #if defined(__APPLE__)
 123 extern
 124 #endif /* NeXT */
 125 struct __res_state _res;
 126
 127 /*
 128  * Set up default settings.  If the configuration file exist, the values
 129  * there will have precedence.  Otherwise, the server address is set to
 130  * INADDR_ANY and the default domain name comes from the gethostname().
 131  *
 132  * An interrim version of this code (BIND 4.9, pre-4.4BSD) used 127.0.0.1
 133  * rather than INADDR_ANY ("0.0.0.0") as the default name server address
 134  * since it was noted that INADDR_ANY actually meant ``the first interface
 135  * you "ifconfig"'d at boot time'' and if this was a SLIP or PPP interface,
 136  * it had to be "up" in order for you to reach your own name server.  It
 137  * was later decided that since the recommended practice is to always
 138  * install local static routes through 127.0.0.1 for all your network
 139  * interfaces, that we could solve this problem without a code change.
 140  *
 141  * The configuration file should always be used, since it is the only way
 142  * to specify a default domain.  If you are running a server on your local
 143  * machine, you should say "nameserver 0.0.0.0" or "nameserver 127.0.0.1"
 144  * in the configuration file.
 145  *
 146  * Return 0 if completes successfully, -1 on error
 147  */
 148 int
 149 res_init()
 150 {
 151         register FILE *fp;
 152         register char *cp, **pp;
 153         register int n;
 154         char buf[BUFSIZ];
 155         int nserv = 0;    /* number of nameserver records read from file */
 156         int haveenv = 0;
 157         int havesearch = 0;
 158 #ifdef RESOLVSORT
 159         int nsort = 0;
 160         char *net;
 161 #endif
 162 #ifndef RFC1535
 163         int dots;
 164 #endif
 165
 166         /*
 167          * These three fields used to be statically initialized.  This made
 168          * it hard to use this code in a shared library.  It is necessary,
 169          * now that we're doing dynamic initialization here, that we preserve
 170          * the old semantics: if an application modifies one of these three
 171          * fields of _res before res_init() is called, res_init() will not
 172          * alter them.  Of course, if an application is setting them to
 173          * _zero_ before calling res_init(), hoping to override what used
 174          * to be the static default, we can't detect it and unexpected results
 175          * will follow.  Zero for any of these fields would make no sense,
 176          * so one can safely assume that the applications were already getting
 177          * unexpected results.
 178          *
 179          * _res.options is tricky since some apps were known to diddle the bits
 180          * before res_init() was first called. We can't replicate that semantic
 181          * with dynamic initialization (they may have turned bits off that are
 182          * set in RES_DEFAULT).  Our solution is to declare such applications
 183          * "broken".  They could fool us by setting RES_INIT but none do (yet).
 184          */
 185         if (!_res.retrans)
 186                 _res.retrans = RES_TIMEOUT;
 187         if (!_res.retry)
 188                 _res.retry = 4;
 189         if (!(_res.options & RES_INIT))
 190                 _res.options = RES_DEFAULT;
 191
 192         /*
 193          * This one used to initialize implicitly to zero, so unless the app
 194          * has set it to something in particular, we can randomize it now.
 195          */
 196         if (!_res.id)
 197                 _res.id = res_randomid();
 198
 199 #ifdef USELOOPBACK
 200         _res.nsaddr.sin_addr = inet_makeaddr(IN_LOOPBACKNET, 1);
 201 #else
 202         _res.nsaddr.sin_addr.s_addr = INADDR_ANY;
 203 #endif
 204         _res.nsaddr.sin_family = AF_INET;
 205         _res.nsaddr.sin_port = htons(NAMESERVER_PORT);
 206         _res.nscount = 1;
 207         _res.ndots = 1;
 208         _res.pfcode = 0;
 209
 210         /* Allow user to override the local domain definition */
 211         if ((cp = getenv("LOCALDOMAIN")) != NULL) {
 212                 (void)strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1);
 213                 haveenv++;
 214
 215                 /*
 216                  * Set search list to be blank-separated strings
 217                  * from rest of env value.  Permits users of LOCALDOMAIN
 218                  * to still have a search list, and anyone to set the
 219                  * one that they want to use as an individual (even more
 220                  * important now that the rfc1535 stuff restricts searches)
 221                  */
 222                 cp = _res.defdname;
 223                 pp = _res.dnsrch;
 224                 *pp++ = cp;
 225                 for (n = 0; *cp && pp < _res.dnsrch + MAXDNSRCH; cp++) {
 226                         if (*cp == '\n')        /* silly backwards compat */
 227                                 break;
 228                         else if (*cp == ' ' || *cp == '\t') {
 229                                 *cp = 0;
 230                                 n = 1;
 231                         } else if (n) {
 232                                 *pp++ = cp;
 233                                 n = 0;
 234                                 havesearch = 1;
 235                         }
 236                 }
 237                 /* null terminate last domain if there are excess */
 238                 while (*cp != '\0' && *cp != ' ' && *cp != '\t' && *cp != '\n')
 239                         cp++;
 240                 *cp = '\0';
 241                 *pp++ = 0;
 242         }
 243
 244 #define MATCH(line, name) \
 245         (!strncmp(line, name, sizeof(name) - 1) && \
 246         (line[sizeof(name) - 1] == ' ' || \
 247          line[sizeof(name) - 1] == '\t'))
 248
 249         if ((fp = fopen(_PATH_RESCONF, "r")) != NULL) {
 250             /* read the config file */
 251             while (fgets(buf, sizeof(buf), fp) != NULL) {
 252                 /* skip comments */
 253                 if (*buf == ';' || *buf == '#')
 254                         continue;
 255                 /* read default domain name */
 256                 if (MATCH(buf, "domain")) {
 257                     if (haveenv)        /* skip if have from environ */
 258                             continue;
 259                     cp = buf + sizeof("domain") - 1;
 260                     while (*cp == ' ' || *cp == '\t')
 261                             cp++;
 262                     if ((*cp == '\0') || (*cp == '\n'))
 263                             continue;
 264                     strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1);
 265                     if ((cp = strpbrk(_res.defdname, " \t\n")) != NULL)
 266                             *cp = '\0';
 267                     havesearch = 0;
 268                     continue;
 269                 }
 270                 /* set search list */
 271                 if (MATCH(buf, "search")) {
 272                     if (haveenv)        /* skip if have from environ */
 273                             continue;
 274                     cp = buf + sizeof("search") - 1;
 275                     while (*cp == ' ' || *cp == '\t')
 276                             cp++;
 277                     if ((*cp == '\0') || (*cp == '\n'))
 278                             continue;
 279                     strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1);
 280                     if ((cp = strchr(_res.defdname, '\n')) != NULL)
 281                             *cp = '\0';
 282                     /*
 283                      * Set search list to be blank-separated strings
 284                      * on rest of line.
 285                      */
 286                     cp = _res.defdname;
 287                     pp = _res.dnsrch;
 288                     *pp++ = cp;
 289                     for (n = 0; *cp && pp < _res.dnsrch + MAXDNSRCH; cp++) {
 290                             if (*cp == ' ' || *cp == '\t') {
 291                                     *cp = 0;
 292                                     n = 1;
 293                             } else if (n) {
 294                                     *pp++ = cp;
 295                                     n = 0;
 296                             }
 297                     }
 298                     /* null terminate last domain if there are excess */
 299                     while (*cp != '\0' && *cp != ' ' && *cp != '\t')
 300                             cp++;
 301                     *cp = '\0';
 302                     *pp++ = 0;
 303                     havesearch = 1;
 304                     continue;
 305                 }
 306                 /* read nameservers to query */
 307                 if (MATCH(buf, "nameserver") && nserv < MAXNS) {
 308                     struct in_addr a;
 309
 310                     cp = buf + sizeof("nameserver") - 1;
 311                     while (*cp == ' ' || *cp == '\t')
 312                         cp++;
 313                     if ((*cp != '\0') && (*cp != '\n') && inet_aton(cp, &a)) {
 314                         _res.nsaddr_list[nserv].sin_addr = a;
 315                         _res.nsaddr_list[nserv].sin_family = AF_INET;
 316                         _res.nsaddr_list[nserv].sin_port =
 317                                 htons(NAMESERVER_PORT);
 318                         nserv++;
 319                     }
 320                     continue;
 321                 }
 322 #ifdef RESOLVSORT
 323                 if (MATCH(buf, "sortlist")) {
 324                     struct in_addr a;
 325
 326                     cp = buf + sizeof("sortlist") - 1;
 327                     while (nsort < MAXRESOLVSORT) {
 328                         while (*cp == ' ' || *cp == '\t')
 329                             cp++;
 330                         if (*cp == '\0' || *cp == '\n' || *cp == ';')
 331                             break;
 332                         net = cp;
 333                         while (*cp && !ISSORTMASK(*cp) && *cp != ';' &&
 334                                isascii(*cp) && !isspace(*cp))
 335                                 cp++;
 336                         n = *cp;
 337                         *cp = 0;
 338                         if (inet_aton(net, &a)) {
 339                             _res.sort_list[nsort].addr = a;
 340                             if (ISSORTMASK(n)) {
 341                                 *cp++ = n;
 342                                 net = cp;
 343                                 while (*cp && *cp != ';' &&
 344                                         isascii(*cp) && !isspace(*cp))
 345                                     cp++;
 346                                 n = *cp;
 347                                 *cp = 0;
 348                                 if (inet_aton(net, &a)) {
 349                                     _res.sort_list[nsort].mask = a.s_addr;
 350                                 } else {
 351                                     _res.sort_list[nsort].mask =
 352                                         net_mask(_res.sort_list[nsort].addr);
 353                                 }
 354                             } else {
 355                                 _res.sort_list[nsort].mask =
 356                                     net_mask(_res.sort_list[nsort].addr);
 357                             }
 358                             nsort++;
 359                         }
 360                         *cp = n;
 361                     }
 362                     continue;
 363                 }
 364 #endif
 365                 if (MATCH(buf, "options")) {
 366                     res_setoptions(buf + sizeof("options") - 1, "conf");
 367                     continue;
 368                 }
 369             }
 370             if (nserv > 1)
 371                 _res.nscount = nserv;
 372 #ifdef RESOLVSORT
 373             _res.nsort = nsort;
 374 #endif
 375             (void) fclose(fp);
 376         }
 377
 378         if (_res.defdname[0] == 0 &&
 379             gethostname(buf, sizeof(_res.defdname) - 1) == 0 &&
 380             (cp = strchr(buf, '.')) != NULL)
 381                 strcpy(_res.defdname, cp + 1);
 382
 383         /* find components of local domain that might be searched */
 384         if (havesearch == 0) {
 385                 pp = _res.dnsrch;
 386                 *pp++ = _res.defdname;
 387                 *pp = NULL;
 388
 389 #ifndef RFC1535
 390                 dots = 0;
 391                 for (cp = _res.defdname; *cp; cp++)
 392                         dots += (*cp == '.');
 393
 394                 cp = _res.defdname;
 395                 while (pp < _res.dnsrch + MAXDFLSRCH) {
 396                         if (dots < LOCALDOMAINPARTS)
 397                                 break;
 398                         cp = strchr(cp, '.') + 1;    /* we know there is one */
 399                         *pp++ = cp;
 400                         dots--;
 401                 }
 402                 *pp = NULL;
 403 #ifdef DEBUG
 404                 if (_res.options & RES_DEBUG) {
 405                         printf(";; res_init()... default dnsrch list:\n");
 406                         for (pp = _res.dnsrch; *pp; pp++)
 407                                 printf(";;\t%s\n", *pp);
 408                         printf(";;\t..END..\n");
 409                 }
 410 #endif /* DEBUG */
 411 #endif /* !RFC1535 */
 412         }
 413
 414         if ((cp = getenv("RES_OPTIONS")) != NULL)
 415                 res_setoptions(cp, "env");
 416         _res.options |= RES_INIT;
 417         return (0);
 418 }
 419
 420 static void
 421 res_setoptions(options, source)
 422         char *options, *source;
 423 {
 424         char *cp = options;
 425         int i;
 426
 427 #ifdef DEBUG
 428         if (_res.options & RES_DEBUG)
 429                 printf(";; res_setoptions(\"%s\", \"%s\")...\n",
 430                        options, source);
 431 #endif
 432         while (*cp) {
 433                 /* skip leading and inner runs of spaces */
 434                 while (*cp == ' ' || *cp == '\t')
 435                         cp++;
 436                 /* search for and process individual options */
 437                 if (!strncmp(cp, "ndots:", sizeof("ndots:") - 1)) {
 438                         i = atoi(cp + sizeof("ndots:") - 1);
 439                         if (i <= RES_MAXNDOTS)
 440                                 _res.ndots = i;
 441                         else
 442                                 _res.ndots = RES_MAXNDOTS;
 443 #ifdef DEBUG
 444                         if (_res.options & RES_DEBUG)
 445                                 printf(";;\tndots=%d\n", _res.ndots);
 446 #endif
 447                 } else if (!strncmp(cp, "debug", sizeof("debug") - 1)) {
 448 #ifdef DEBUG
 449                         if (!(_res.options & RES_DEBUG)) {
 450                                 printf(";; res_setoptions(\"%s\", \"%s\")..\n",
 451                                        options, source);
 452                                 _res.options |= RES_DEBUG;
 453                         }
 454                         printf(";;\tdebug\n");
 455 #endif
 456                 } else {
 457                         /* XXX - print a warning here? */
 458                 }
 459                 /* skip to next run of spaces */
 460                 while (*cp && *cp != ' ' && *cp != '\t')
 461                         cp++;
 462         }
 463 }
 464
 465 #ifdef RESOLVSORT
 466 /* XXX - should really support CIDR which means explicit masks always. */
 467 static u_int32_t
 468 net_mask(in)            /* XXX - should really use system's version of this */
 469         struct in_addr in;
 470 {
 471         register u_int32_t i = ntohl(in.s_addr);
 472
 473         if (IN_CLASSA(i))
 474                 return (htonl(IN_CLASSA_NET));
 475         else if (IN_CLASSB(i))
 476                 return (htonl(IN_CLASSB_NET));
 477         return (htonl(IN_CLASSC_NET));
 478 }
 479 #endif
 480
 481 u_int16_t
 482 res_randomid()
 483 {
 484         struct timeval now;
 485
 486         gettimeofday(&now, NULL);
 487         return (0xffff & (now.tv_sec ^ now.tv_usec ^ getpid()));
 488 }