StdLib/BsdSocketLib/res_init.c

   1 /*
   2  * Copyright (c) 1985, 1989, 1993
   3  *    The Regents of the University of California.  All rights reserved.
   4  *
   5  * Portions copyright (c) 1999, 2000
   6  * Intel Corporation.
   7  * All rights reserved.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  *
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  *
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in the
  18  *    documentation and/or other materials provided with the distribution.
  19  *
  20  * 3. All advertising materials mentioning features or use of this software
  21  *    must display the following acknowledgement:
  22  *
  23  *    This product includes software developed by the University of
  24  *    California, Berkeley, Intel Corporation, and its contributors.
  25  *
  26  * 4. Neither the name of University, Intel Corporation, or their respective
  27  *    contributors may be used to endorse or promote products derived from
  28  *    this software without specific prior written permission.
  29  *
  30  * THIS SOFTWARE IS PROVIDED BY THE REGENTS, INTEL CORPORATION AND
  31  * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
  32  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  33  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS,
  34  * INTEL CORPORATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  35  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  36  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  37  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  38  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  39  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  40  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  41  *
  42  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  43  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  44  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  45  * SUCH DAMAGE.
  46  */
  47
  48 /*
  49  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
  50  *
  51  * Permission to use, copy, modify, and distribute this software for any
  52  * purpose with or without fee is hereby granted, provided that the above
  53  * copyright notice and this permission notice appear in all copies, and that
  54  * the name of Digital Equipment Corporation not be used in advertising or
  55  * publicity pertaining to distribution of the document or software without
  56  * specific, written prior permission.
  57  *
  58  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
  59  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
  60  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
  61  * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  62  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  63  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  64  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  65  * SOFTWARE.
  66  */
  67
  68 /*
  69  * Portions Copyright (c) 1996 by Internet Software Consortium.
  70  *
  71  * Permission to use, copy, modify, and distribute this software for any
  72  * purpose with or without fee is hereby granted, provided that the above
  73  * copyright notice and this permission notice appear in all copies.
  74  *
  75  * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
  76  * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
  77  * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
  78  * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  79  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  80  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  81  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  82  * SOFTWARE.
  83  */
  84
  85 #if defined(LIBC_SCCS) && !defined(lint)
  86 static char sccsid[] = "@(#)res_init.c  8.1 (Berkeley) 6/7/93";
  87 static char orig_rcsid[] = "From: Id: res_init.c,v 8.7 1996/11/18 09:10:04 vixie Exp $";
  88 static char rcsid[] = "$Id: res_init.c,v 1.1.1.1 2003/11/19 01:51:37 kyu3 Exp $";
  89 #endif /* LIBC_SCCS and not lint */
  90
  91 #include <sys/types.h>
  92 #include <sys/param.h>
  93 #include <sys/socket.h>
  94 #include <sys/time.h>
  95 #include <netinet/in.h>
  96 #include <arpa/inet.h>
  97 #include <arpa/nameser.h>
  98 #include <ctype.h>
  99 #include <resolv.h>
 100 #include <stdio.h>
 101 #include <stdlib.h>
 102 #include <string.h>
 103 #include <unistd.h>
 104
 105 #include "res_config.h"
 106
 107 static void res_setoptions __P((char *, char *));
 108
 109 #ifdef RESOLVSORT
 110 static const char sort_mask[] = "/&";
 111 #define ISSORTMASK(ch) (strchr(sort_mask, ch) != NULL)
 112 static u_int32_t net_mask __P((struct in_addr));
 113 #endif
 114
 115 #if !defined(isascii) /* XXX - could be a function */
 116 # define isascii(c) (!(c & 0200))
 117 #endif
 118
 119 /*
 120  * Resolver state default settings.
 121  */
 122
 123 struct __res_state _res
 124 # if defined(__BIND_RES_TEXT)
 125     = { RES_TIMEOUT, }  /* Motorola, et al. */
 126 # endif
 127     ;
 128
 129
 130 /*
 131  * Set up default settings.  If the configuration file exist, the values
 132  * there will have precedence.  Otherwise, the server address is set to
 133  * INADDR_ANY and the default domain name comes from the gethostname().
 134  *
 135  * An interrim version of this code (BIND 4.9, pre-4.4BSD) used 127.0.0.1
 136  * rather than INADDR_ANY ("0.0.0.0") as the default name server address
 137  * since it was noted that INADDR_ANY actually meant ``the first interface
 138  * you "ifconfig"'d at boot time'' and if this was a SLIP or PPP interface,
 139  * it had to be "up" in order for you to reach your own name server.  It
 140  * was later decided that since the recommended practice is to always
 141  * install local static routes through 127.0.0.1 for all your network
 142  * interfaces, that we could solve this problem without a code change.
 143  *
 144  * The configuration file should always be used, since it is the only way
 145  * to specify a default domain.  If you are running a server on your local
 146  * machine, you should say "nameserver 0.0.0.0" or "nameserver 127.0.0.1"
 147  * in the configuration file.
 148  *
 149  * Return 0 if completes successfully, -1 on error
 150  */
 151 int
 152 res_init()
 153 {
 154     register FILE *fp;
 155     register char *cp, **pp;
 156     register int n;
 157     char buf[MAXDNAME];
 158     int nserv = 0;    /* number of nameserver records read from file */
 159     int haveenv = 0;
 160     int havesearch = 0;
 161 #ifdef RESOLVSORT
 162     int nsort = 0;
 163     char *net;
 164 #endif
 165 #ifndef RFC1535
 166     int dots;
 167 #endif
 168
 169     /*
 170      * These three fields used to be statically initialized.  This made
 171      * it hard to use this code in a shared library.  It is necessary,
 172      * now that we're doing dynamic initialization here, that we preserve
 173      * the old semantics: if an application modifies one of these three
 174      * fields of _res before res_init() is called, res_init() will not
 175      * alter them.  Of course, if an application is setting them to
 176      * _zero_ before calling res_init(), hoping to override what used
 177      * to be the static default, we can't detect it and unexpected results
 178      * will follow.  Zero for any of these fields would make no sense,
 179      * so one can safely assume that the applications were already getting
 180      * unexpected results.
 181      *
 182      * _res.options is tricky since some apps were known to diddle the bits
 183      * before res_init() was first called. We can't replicate that semantic
 184      * with dynamic initialization (they may have turned bits off that are
 185      * set in RES_DEFAULT).  Our solution is to declare such applications
 186      * "broken".  They could fool us by setting RES_INIT but none do (yet).
 187      */
 188     if (!_res.retrans)
 189         _res.retrans = RES_TIMEOUT;
 190     if (!_res.retry)
 191         _res.retry = 4;
 192     if (!(_res.options & RES_INIT))
 193         _res.options = RES_DEFAULT;
 194
 195     /*
 196      * This one used to initialize implicitly to zero, so unless the app
 197      * has set it to something in particular, we can randomize it now.
 198      */
 199     if (!_res.id)
 200         _res.id = (u_short)res_randomid();
 201
 202 #ifdef USELOOPBACK
 203     _res.nsaddr.sin_addr = inet_makeaddr(IN_LOOPBACKNET, 1);
 204 #else
 205     _res.nsaddr.sin_addr.s_addr = INADDR_ANY;
 206 #endif
 207     _res.nsaddr.sin_family = AF_INET;
 208     _res.nsaddr.sin_port = htons(NAMESERVER_PORT);
 209     _res.nscount = 1;
 210     _res.ndots = 1;
 211     _res.pfcode = 0;
 212
 213     /* Allow user to override the local domain definition */
 214 #ifdef _ORG_FREEBSD_
 215     if (issetugid() == 0 && (cp = getenv("LOCALDOMAIN")) != NULL)
 216 #else
 217     if ((cp = getenv("LOCALDOMAIN")) != NULL)
 218 #endif
 219     {
 220         (void)strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1);
 221         _res.defdname[sizeof(_res.defdname) - 1] = '\0';
 222         haveenv++;
 223
 224         /*
 225          * Set search list to be blank-separated strings
 226          * from rest of env value.  Permits users of LOCALDOMAIN
 227          * to still have a search list, and anyone to set the
 228          * one that they want to use as an individual (even more
 229          * important now that the rfc1535 stuff restricts searches)
 230          */
 231         cp = _res.defdname;
 232         pp = _res.dnsrch;
 233         *pp++ = cp;
 234         for (n = 0; *cp && pp < _res.dnsrch + MAXDNSRCH; cp++) {
 235             if (*cp == '\n')    /* silly backwards compat */
 236                 break;
 237             else if (*cp == ' ' || *cp == '\t') {
 238                 *cp = 0;
 239                 n = 1;
 240             } else if (n) {
 241                 *pp++ = cp;
 242                 n = 0;
 243                 havesearch = 1;
 244             }
 245         }
 246         /* null terminate last domain if there are excess */
 247         while (*cp != '\0' && *cp != ' ' && *cp != '\t' && *cp != '\n')
 248             cp++;
 249         *cp = '\0';
 250         *pp++ = 0;
 251     }
 252
 253 #define MATCH(line, name) \
 254     (!strncmp(line, name, sizeof(name) - 1) && \
 255     (line[sizeof(name) - 1] == ' ' || \
 256      line[sizeof(name) - 1] == '\t'))
 257
 258     if ((fp = fopen(_PATH_RESCONF, "r")) != NULL) {
 259         /* read the config file */
 260         while (fgets(buf, sizeof(buf), fp) != NULL) {
 261         /* skip comments */
 262         if (*buf == ';' || *buf == '#')
 263             continue;
 264         /* read default domain name */
 265         if (MATCH(buf, "domain")) {
 266             if (haveenv)    /* skip if have from environ */
 267                 continue;
 268             cp = buf + sizeof("domain") - 1;
 269             while (*cp == ' ' || *cp == '\t')
 270                 cp++;
 271             if ((*cp == '\0') || (*cp == '\n'))
 272                 continue;
 273             strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1);
 274             _res.defdname[sizeof(_res.defdname) - 1] = '\0';
 275             if ((cp = strpbrk(_res.defdname, " \t\n")) != NULL)
 276                 *cp = '\0';
 277             havesearch = 0;
 278             continue;
 279         }
 280         /* set search list */
 281         if (MATCH(buf, "search")) {
 282             if (haveenv)    /* skip if have from environ */
 283                 continue;
 284             cp = buf + sizeof("search") - 1;
 285             while (*cp == ' ' || *cp == '\t')
 286                 cp++;
 287             if ((*cp == '\0') || (*cp == '\n'))
 288                 continue;
 289             strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1);
 290             _res.defdname[sizeof(_res.defdname) - 1] = '\0';
 291             if ((cp = strchr(_res.defdname, '\n')) != NULL)
 292                 *cp = '\0';
 293             /*
 294              * Set search list to be blank-separated strings
 295              * on rest of line.
 296              */
 297             cp = _res.defdname;
 298             pp = _res.dnsrch;
 299             *pp++ = cp;
 300             for (n = 0; *cp && pp < _res.dnsrch + MAXDNSRCH; cp++) {
 301                 if (*cp == ' ' || *cp == '\t') {
 302                     *cp = 0;
 303                     n = 1;
 304                 } else if (n) {
 305                     *pp++ = cp;
 306                     n = 0;
 307                 }
 308             }
 309             /* null terminate last domain if there are excess */
 310             while (*cp != '\0' && *cp != ' ' && *cp != '\t')
 311                 cp++;
 312             *cp = '\0';
 313             *pp++ = 0;
 314             havesearch = 1;
 315             continue;
 316         }
 317         /* read nameservers to query */
 318         if (MATCH(buf, "nameserver") && nserv < MAXNS) {
 319             struct in_addr a;
 320
 321             cp = buf + sizeof("nameserver") - 1;
 322             while (*cp == ' ' || *cp == '\t')
 323             cp++;
 324             if ((*cp != '\0') && (*cp != '\n') && inet_aton(cp, &a)) {
 325             _res.nsaddr_list[nserv].sin_addr = a;
 326             _res.nsaddr_list[nserv].sin_family = AF_INET;
 327             _res.nsaddr_list[nserv].sin_port =
 328                 htons(NAMESERVER_PORT);
 329             nserv++;
 330             }
 331             continue;
 332         }
 333 #ifdef RESOLVSORT
 334         if (MATCH(buf, "sortlist")) {
 335             struct in_addr a;
 336
 337             cp = buf + sizeof("sortlist") - 1;
 338             while (nsort < MAXRESOLVSORT) {
 339             while (*cp == ' ' || *cp == '\t')
 340                 cp++;
 341             if (*cp == '\0' || *cp == '\n' || *cp == ';')
 342                 break;
 343             net = cp;
 344             while (*cp && !ISSORTMASK(*cp) && *cp != ';' &&
 345                    isascii(*cp) && !isspace(*cp))
 346                 cp++;
 347             n = *cp;
 348             *cp = 0;
 349             if (inet_aton(net, &a)) {
 350                 _res.sort_list[nsort].addr = a;
 351                 if (ISSORTMASK(n)) {
 352                 *cp++ = (char)n;
 353                 net = cp;
 354                 while (*cp && *cp != ';' &&
 355                     isascii(*cp) && !isspace(*cp))
 356                     cp++;
 357                 n = *cp;
 358                 *cp = 0;
 359                 if (inet_aton(net, &a)) {
 360                     _res.sort_list[nsort].mask = a.s_addr;
 361                 } else {
 362                     _res.sort_list[nsort].mask =
 363                     net_mask(_res.sort_list[nsort].addr);
 364                 }
 365                 } else {
 366                 _res.sort_list[nsort].mask =
 367                     net_mask(_res.sort_list[nsort].addr);
 368                 }
 369                 nsort++;
 370             }
 371             *cp = (char)n;
 372             }
 373             continue;
 374         }
 375 #endif
 376         if (MATCH(buf, "options")) {
 377             res_setoptions(buf + sizeof("options") - 1, "conf");
 378             continue;
 379         }
 380         }
 381         if (nserv > 1)
 382         _res.nscount = nserv;
 383 #ifdef RESOLVSORT
 384         _res.nsort = nsort;
 385 #endif
 386         (void) fclose(fp);
 387     }
 388     if (_res.defdname[0] == 0 &&
 389         gethostname(buf, sizeof(_res.defdname) - 1) == 0 &&
 390         (cp = strchr(buf, '.')) != NULL)
 391         strcpy(_res.defdname, cp + 1);
 392
 393     /* find components of local domain that might be searched */
 394     if (havesearch == 0) {
 395         pp = _res.dnsrch;
 396         *pp++ = _res.defdname;
 397         *pp = NULL;
 398
 399 #ifndef RFC1535
 400         dots = 0;
 401         for (cp = _res.defdname; *cp; cp++)
 402             dots += (*cp == '.');
 403
 404         cp = _res.defdname;
 405         while (pp < _res.dnsrch + MAXDFLSRCH) {
 406             if (dots < LOCALDOMAINPARTS)
 407                 break;
 408             cp = strchr(cp, '.') + 1;    /* we know there is one */
 409             *pp++ = cp;
 410             dots--;
 411         }
 412         *pp = NULL;
 413 #ifdef DEBUG
 414         if (_res.options & RES_DEBUG) {
 415             printf(";; res_init()... default dnsrch list:\n");
 416             for (pp = _res.dnsrch; *pp; pp++)
 417                 printf(";;\t%s\n", *pp);
 418             printf(";;\t..END..\n");
 419         }
 420 #endif
 421 #endif /* !RFC1535 */
 422     }
 423
 424 #ifdef _ORG_FREEBSD_
 425     if (issetugid())
 426 #else
 427     if (1)
 428 #endif
 429         _res.options |= RES_NOALIASES;
 430     else if ((cp = getenv("RES_OPTIONS")) != NULL)
 431         res_setoptions(cp, "env");
 432     _res.options |= RES_INIT;
 433     if ( 0 == nserv ) {
 434       return -1;
 435     }
 436     return (0);
 437 }
 438
 439 static void
 440 res_setoptions(
 441     char *options,
 442     char *source
 443     )
 444 {
 445     char *cp = options;
 446     int i;
 447
 448 #ifdef DEBUG
 449     if (_res.options & RES_DEBUG)
 450         printf(";; res_setoptions(\"%s\", \"%s\")...\n",
 451                options, source);
 452 #endif
 453     while (*cp) {
 454         /* skip leading and inner runs of spaces */
 455         while (*cp == ' ' || *cp == '\t')
 456             cp++;
 457         /* search for and process individual options */
 458         if (!strncmp(cp, "ndots:", sizeof("ndots:") - 1)) {
 459             i = atoi(cp + sizeof("ndots:") - 1);
 460             if (i <= RES_MAXNDOTS)
 461                 _res.ndots = i;
 462             else
 463                 _res.ndots = RES_MAXNDOTS;
 464 #ifdef DEBUG
 465             if (_res.options & RES_DEBUG)
 466                 printf(";;\tndots=%d\n", _res.ndots);
 467 #endif
 468         } else if (!strncmp(cp, "debug", sizeof("debug") - 1)) {
 469 #ifdef DEBUG
 470             if (!(_res.options & RES_DEBUG)) {
 471                 printf(";; res_setoptions(\"%s\", \"%s\")..\n",
 472                        options, source);
 473                 _res.options |= RES_DEBUG;
 474             }
 475             printf(";;\tdebug\n");
 476 #endif
 477         } else if (!strncmp(cp, "inet6", sizeof("inet6") - 1)) {
 478             _res.options |= RES_USE_INET6;
 479         } else if (!strncmp(cp, "no_tld_query", sizeof("no_tld_query") - 1)) {
 480             _res.options |= RES_NOTLDQUERY;
 481         } else {
 482             /* XXX - print a warning here? */
 483         }
 484         /* skip to next run of spaces */
 485         while (*cp && *cp != ' ' && *cp != '\t')
 486             cp++;
 487     }
 488 }
 489
 490 #ifdef RESOLVSORT
 491 /* XXX - should really support CIDR which means explicit masks always. */
 492 static u_int32_t
 493 net_mask(
 494     struct in_addr in
 495     )
 496 {
 497     register u_int32_t i = ntohl(in.s_addr);
 498
 499     if (IN_CLASSA(i))
 500         return (htonl(IN_CLASSA_NET));
 501     else if (IN_CLASSB(i))
 502         return (htonl(IN_CLASSB_NET));
 503     return (htonl(IN_CLASSC_NET));
 504 }
 505 #endif
 506
 507 u_int
 508 res_randomid()
 509 {
 510     struct timeval now;
 511
 512     gettimeofday(&now, NULL);
 513     return (0xffff & (now.tv_sec ^ now.tv_usec /* ^ getpid() */));
 514 }