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
  90 #include <stdio.h>
  91 #include <ctype.h>
  92
  93 #include "nameser8_compat.h"
  94 #include "resolv8_compat.h"
  95
  96 #if defined(BSD) && (BSD >= 199103)
  97 # include <unistd.h>
  98 # include <stdlib.h>
  99 # include <string.h>
 100 #else
 101 # include "portability.h"
 102 #endif
 103
 104 #if defined(USE_OPTIONS_H)
 105 # include "options.h"
 106 #endif
 107
 108 static void res_setoptions __P((char *, char *));
 109
 110 #ifdef RESOLVSORT
 111 static const char sort_mask[] = "/&";
 112 #define ISSORTMASK(ch) (strchr(sort_mask, ch) != NULL)
 113 static u_int32_t net_mask __P((struct in_addr));
 114 #endif
 115
 116 #if !defined(isascii)   /* XXX - could be a function */
 117 # define isascii(c) (!(c & 0200))
 118 #endif
 119
 120 /*
 121  * Resolver state default settings.
 122  */
 123
 124 #if defined(__APPLE__)
 125 extern
 126 #endif /* NeXT */
 127 struct __res_state _res;
 128
 129 /*
 130  * Set up default settings.  If the configuration file exist, the values
 131  * there will have precedence.  Otherwise, the server address is set to
 132  * INADDR_ANY and the default domain name comes from the gethostname().
 133  *
 134  * An interrim version of this code (BIND 4.9, pre-4.4BSD) used 127.0.0.1
 135  * rather than INADDR_ANY ("0.0.0.0") as the default name server address
 136  * since it was noted that INADDR_ANY actually meant ``the first interface
 137  * you "ifconfig"'d at boot time'' and if this was a SLIP or PPP interface,
 138  * it had to be "up" in order for you to reach your own name server.  It
 139  * was later decided that since the recommended practice is to always
 140  * install local static routes through 127.0.0.1 for all your network
 141  * interfaces, that we could solve this problem without a code change.
 142  *
 143  * The configuration file should always be used, since it is the only way
 144  * to specify a default domain.  If you are running a server on your local
 145  * machine, you should say "nameserver 0.0.0.0" or "nameserver 127.0.0.1"
 146  * in the configuration file.
 147  *
 148  * Return 0 if completes successfully, -1 on error
 149  */
 150 int
 151 res_init()
 152 {
 153         register FILE *fp;
 154         register char *cp, **pp;
 155         register int n;
 156         char buf[BUFSIZ];
 157         int nserv = 0;    /* number of nameserver records read from file */
 158         int haveenv = 0;
 159         int havesearch = 0;
 160 #ifdef RESOLVSORT
 161         int nsort = 0;
 162         char *net;
 163 #endif
 164 #ifndef RFC1535
 165         int dots;
 166 #endif
 167
 168         /*
 169          * These three fields used to be statically initialized.  This made
 170          * it hard to use this code in a shared library.  It is necessary,
 171          * now that we're doing dynamic initialization here, that we preserve
 172          * the old semantics: if an application modifies one of these three
 173          * fields of _res before res_init() is called, res_init() will not
 174          * alter them.  Of course, if an application is setting them to
 175          * _zero_ before calling res_init(), hoping to override what used
 176          * to be the static default, we can't detect it and unexpected results
 177          * will follow.  Zero for any of these fields would make no sense,
 178          * so one can safely assume that the applications were already getting
 179          * unexpected results.
 180          *
 181          * _res.options is tricky since some apps were known to diddle the bits
 182          * before res_init() was first called. We can't replicate that semantic
 183          * with dynamic initialization (they may have turned bits off that are
 184          * set in RES_DEFAULT).  Our solution is to declare such applications
 185          * "broken".  They could fool us by setting RES_INIT but none do (yet).
 186          */
 187         if (!_res.retrans)
 188                 _res.retrans = RES_TIMEOUT;
 189         if (!_res.retry)
 190                 _res.retry = 4;
 191         if (!(_res.options & RES_INIT))
 192                 _res.options = RES_DEFAULT;
 193
 194         /*
 195          * This one used to initialize implicitly to zero, so unless the app
 196          * has set it to something in particular, we can randomize it now.
 197          */
 198         if (!_res.id)
 199                 _res.id = res_randomid();
 200
 201 #ifdef USELOOPBACK
 202         _res.nsaddr.sin_addr = inet_makeaddr(IN_LOOPBACKNET, 1);
 203 #else
 204         _res.nsaddr.sin_addr.s_addr = INADDR_ANY;
 205 #endif
 206         _res.nsaddr.sin_family = AF_INET;
 207         _res.nsaddr.sin_port = htons(NAMESERVER_PORT);
 208         _res.nscount = 1;
 209         _res.ndots = 1;
 210         _res.pfcode = 0;
 211
 212         /* Allow user to override the local domain definition */
 213         if ((cp = getenv("LOCALDOMAIN")) != NULL) {
 214                 (void)strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1);
 215                 haveenv++;
 216
 217                 /*
 218                  * Set search list to be blank-separated strings
 219                  * from rest of env value.  Permits users of LOCALDOMAIN
 220                  * to still have a search list, and anyone to set the
 221                  * one that they want to use as an individual (even more
 222                  * important now that the rfc1535 stuff restricts searches)
 223                  */
 224                 cp = _res.defdname;
 225                 pp = _res.dnsrch;
 226                 *pp++ = cp;
 227                 for (n = 0; *cp && pp < _res.dnsrch + MAXDNSRCH; cp++) {
 228                         if (*cp == '\n')        /* silly backwards compat */
 229                                 break;
 230                         else if (*cp == ' ' || *cp == '\t') {
 231                                 *cp = 0;
 232                                 n = 1;
 233                         } else if (n) {
 234                                 *pp++ = cp;
 235                                 n = 0;
 236                                 havesearch = 1;
 237                         }
 238                 }
 239                 /* null terminate last domain if there are excess */
 240                 while (*cp != '\0' && *cp != ' ' && *cp != '\t' && *cp != '\n')
 241                         cp++;
 242                 *cp = '\0';
 243                 *pp++ = 0;
 244         }
 245
 246 #define MATCH(line, name) \
 247         (!strncmp(line, name, sizeof(name) - 1) && \
 248         (line[sizeof(name) - 1] == ' ' || \
 249          line[sizeof(name) - 1] == '\t'))
 250
 251         if ((fp = fopen(_PATH_RESCONF, "r")) != NULL) {
 252             /* read the config file */
 253             while (fgets(buf, sizeof(buf), fp) != NULL) {
 254                 /* skip comments */
 255                 if (*buf == ';' || *buf == '#')
 256                         continue;
 257                 /* read default domain name */
 258                 if (MATCH(buf, "domain")) {
 259                     if (haveenv)        /* skip if have from environ */
 260                             continue;
 261                     cp = buf + sizeof("domain") - 1;
 262                     while (*cp == ' ' || *cp == '\t')
 263                             cp++;
 264                     if ((*cp == '\0') || (*cp == '\n'))
 265                             continue;
 266                     strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1);
 267                     if ((cp = strpbrk(_res.defdname, " \t\n")) != NULL)
 268                             *cp = '\0';
 269                     havesearch = 0;
 270                     continue;
 271                 }
 272                 /* set search list */
 273                 if (MATCH(buf, "search")) {
 274                     if (haveenv)        /* skip if have from environ */
 275                             continue;
 276                     cp = buf + sizeof("search") - 1;
 277                     while (*cp == ' ' || *cp == '\t')
 278                             cp++;
 279                     if ((*cp == '\0') || (*cp == '\n'))
 280                             continue;
 281                     strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1);
 282                     if ((cp = strchr(_res.defdname, '\n')) != NULL)
 283                             *cp = '\0';
 284                     /*
 285                      * Set search list to be blank-separated strings
 286                      * on rest of line.
 287                      */
 288                     cp = _res.defdname;
 289                     pp = _res.dnsrch;
 290                     *pp++ = cp;
 291                     for (n = 0; *cp && pp < _res.dnsrch + MAXDNSRCH; cp++) {
 292                             if (*cp == ' ' || *cp == '\t') {
 293                                     *cp = 0;
 294                                     n = 1;
 295                             } else if (n) {
 296                                     *pp++ = cp;
 297                                     n = 0;
 298                             }
 299                     }
 300                     /* null terminate last domain if there are excess */
 301                     while (*cp != '\0' && *cp != ' ' && *cp != '\t')
 302                             cp++;
 303                     *cp = '\0';
 304                     *pp++ = 0;
 305                     havesearch = 1;
 306                     continue;
 307                 }
 308                 /* read nameservers to query */
 309                 if (MATCH(buf, "nameserver") && nserv < MAXNS) {
 310                     struct in_addr a;
 311
 312                     cp = buf + sizeof("nameserver") - 1;
 313                     while (*cp == ' ' || *cp == '\t')
 314                         cp++;
 315                     if ((*cp != '\0') && (*cp != '\n') && inet_aton(cp, &a)) {
 316                         _res.nsaddr_list[nserv].sin_addr = a;
 317                         _res.nsaddr_list[nserv].sin_family = AF_INET;
 318                         _res.nsaddr_list[nserv].sin_port =
 319                                 htons(NAMESERVER_PORT);
 320                         nserv++;
 321                     }
 322                     continue;
 323                 }
 324 #ifdef RESOLVSORT
 325                 if (MATCH(buf, "sortlist")) {
 326                     struct in_addr a;
 327
 328                     cp = buf + sizeof("sortlist") - 1;
 329                     while (nsort < MAXRESOLVSORT) {
 330                         while (*cp == ' ' || *cp == '\t')
 331                             cp++;
 332                         if (*cp == '\0' || *cp == '\n' || *cp == ';')
 333                             break;
 334                         net = cp;
 335                         while (*cp && !ISSORTMASK(*cp) && *cp != ';' &&
 336                                isascii(*cp) && !isspace(*cp))
 337                                 cp++;
 338                         n = *cp;
 339                         *cp = 0;
 340                         if (inet_aton(net, &a)) {
 341                             _res.sort_list[nsort].addr = a;
 342                             if (ISSORTMASK(n)) {
 343                                 *cp++ = n;
 344                                 net = cp;
 345                                 while (*cp && *cp != ';' &&
 346                                         isascii(*cp) && !isspace(*cp))
 347                                     cp++;
 348                                 n = *cp;
 349                                 *cp = 0;
 350                                 if (inet_aton(net, &a)) {
 351                                     _res.sort_list[nsort].mask = a.s_addr;
 352                                 } else {
 353                                     _res.sort_list[nsort].mask =
 354                                         net_mask(_res.sort_list[nsort].addr);
 355                                 }
 356                             } else {
 357                                 _res.sort_list[nsort].mask =
 358                                     net_mask(_res.sort_list[nsort].addr);
 359                             }
 360                             nsort++;
 361                         }
 362                         *cp = n;
 363                     }
 364                     continue;
 365                 }
 366 #endif
 367                 if (MATCH(buf, "options")) {
 368                     res_setoptions(buf + sizeof("options") - 1, "conf");
 369                     continue;
 370                 }
 371             }
 372             if (nserv > 1)
 373                 _res.nscount = nserv;
 374 #ifdef RESOLVSORT
 375             _res.nsort = nsort;
 376 #endif
 377             (void) fclose(fp);
 378         }
 379
 380         if (_res.defdname[0] == 0 &&
 381             gethostname(buf, sizeof(_res.defdname) - 1) == 0 &&
 382             (cp = strchr(buf, '.')) != NULL)
 383                 strcpy(_res.defdname, cp + 1);
 384
 385         /* find components of local domain that might be searched */
 386         if (havesearch == 0) {
 387                 pp = _res.dnsrch;
 388                 *pp++ = _res.defdname;
 389                 *pp = NULL;
 390
 391 #ifndef RFC1535
 392                 dots = 0;
 393                 for (cp = _res.defdname; *cp; cp++)
 394                         dots += (*cp == '.');
 395
 396                 cp = _res.defdname;
 397                 while (pp < _res.dnsrch + MAXDFLSRCH) {
 398                         if (dots < LOCALDOMAINPARTS)
 399                                 break;
 400                         cp = strchr(cp, '.') + 1;    /* we know there is one */
 401                         *pp++ = cp;
 402                         dots--;
 403                 }
 404                 *pp = NULL;
 405 #ifdef DEBUG
 406                 if (_res.options & RES_DEBUG) {
 407                         printf(";; res_init()... default dnsrch list:\n");
 408                         for (pp = _res.dnsrch; *pp; pp++)
 409                                 printf(";;\t%s\n", *pp);
 410                         printf(";;\t..END..\n");
 411                 }
 412 #endif /* DEBUG */
 413 #endif /* !RFC1535 */
 414         }
 415
 416         if ((cp = getenv("RES_OPTIONS")) != NULL)
 417                 res_setoptions(cp, "env");
 418         _res.options |= RES_INIT;
 419         return (0);
 420 }
 421
 422 static void
 423 res_setoptions(options, source)
 424         char *options, *source;
 425 {
 426         char *cp = options;
 427         int i;
 428
 429 #ifdef DEBUG
 430         if (_res.options & RES_DEBUG)
 431                 printf(";; res_setoptions(\"%s\", \"%s\")...\n",
 432                        options, source);
 433 #endif
 434         while (*cp) {
 435                 /* skip leading and inner runs of spaces */
 436                 while (*cp == ' ' || *cp == '\t')
 437                         cp++;
 438                 /* search for and process individual options */
 439                 if (!strncmp(cp, "ndots:", sizeof("ndots:") - 1)) {
 440                         i = atoi(cp + sizeof("ndots:") - 1);
 441                         if (i <= RES_MAXNDOTS)
 442                                 _res.ndots = i;
 443                         else
 444                                 _res.ndots = RES_MAXNDOTS;
 445 #ifdef DEBUG
 446                         if (_res.options & RES_DEBUG)
 447                                 printf(";;\tndots=%d\n", _res.ndots);
 448 #endif
 449                 } else if (!strncmp(cp, "debug", sizeof("debug") - 1)) {
 450 #ifdef DEBUG
 451                         if (!(_res.options & RES_DEBUG)) {
 452                                 printf(";; res_setoptions(\"%s\", \"%s\")..\n",
 453                                        options, source);
 454                                 _res.options |= RES_DEBUG;
 455                         }
 456                         printf(";;\tdebug\n");
 457 #endif
 458                 } else {
 459                         /* XXX - print a warning here? */
 460                 }
 461                 /* skip to next run of spaces */
 462                 while (*cp && *cp != ' ' && *cp != '\t')
 463                         cp++;
 464         }
 465 }
 466
 467 #ifdef RESOLVSORT
 468 /* XXX - should really support CIDR which means explicit masks always. */
 469 static u_int32_t
 470 net_mask(in)            /* XXX - should really use system's version of this */
 471         struct in_addr in;
 472 {
 473         register u_int32_t i = ntohl(in.s_addr);
 474
 475         if (IN_CLASSA(i))
 476                 return (htonl(IN_CLASSA_NET));
 477         else if (IN_CLASSB(i))
 478                 return (htonl(IN_CLASSB_NET));
 479         return (htonl(IN_CLASSC_NET));
 480 }
 481 #endif
 482
 483 u_int16_t
 484 res_randomid()
 485 {
 486         struct timeval now;
 487
 488         gettimeofday(&now, NULL);
 489         return (0xffff & (now.tv_sec ^ now.tv_usec ^ getpid()));
 490 }