resolv/res_init.c

   1 /*
   2  * Copyright (c) 1985, 1989, 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  * 4. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 /*
  31  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
  32  *
  33  * Permission to use, copy, modify, and distribute this software for any
  34  * purpose with or without fee is hereby granted, provided that the above
  35  * copyright notice and this permission notice appear in all copies, and that
  36  * the name of Digital Equipment Corporation not be used in advertising or
  37  * publicity pertaining to distribution of the document or software without
  38  * specific, written prior permission.
  39  *
  40  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
  41  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
  42  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
  43  * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  44  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  45  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  46  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  47  * SOFTWARE.
  48  */
  49
  50 /*
  51  * Portions Copyright (c) 1996-1999 by Internet Software Consortium.
  52  *
  53  * Permission to use, copy, modify, and distribute this software for any
  54  * purpose with or without fee is hereby granted, provided that the above
  55  * copyright notice and this permission notice appear in all copies.
  56  *
  57  * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
  58  * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
  59  * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
  60  * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  61  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  62  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  63  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  64  * SOFTWARE.
  65  */
  66
  67 #if defined(LIBC_SCCS) && !defined(lint)
  68 static const char sccsid[] = "@(#)res_init.c    8.1 (Berkeley) 6/7/93";
  69 static const char rcsid[] = "$BINDId: res_init.c,v 8.16 2000/05/09 07:10:12 vixie Exp $";
  70 #endif /* LIBC_SCCS and not lint */
  71
  72 #include <sys/types.h>
  73 #include <sys/param.h>
  74 #include <sys/socket.h>
  75 #include <sys/time.h>
  76
  77 #include <netinet/in.h>
  78 #include <arpa/inet.h>
  79 #include <arpa/nameser.h>
  80
  81 #include <ctype.h>
  82 #include <resolv.h>
  83 #include <stdio.h>
  84 #include <stdio_ext.h>
  85 #include <stdlib.h>
  86 #include <string.h>
  87 #include <unistd.h>
  88
  89 /* Options.  Should all be left alone. */
  90 #define RESOLVSORT
  91 #define RFC1535
  92 /* #undef DEBUG */
  93
  94 static void res_setoptions (res_state, const char *, const char *)
  95      internal_function;
  96
  97 #ifdef RESOLVSORT
  98 static const char sort_mask[] = "/&";
  99 #define ISSORTMASK(ch) (strchr(sort_mask, ch) != NULL)
 100 static u_int32_t net_mask __P((struct in_addr));
 101 #endif
 102
 103 #if !defined(isascii)   /* XXX - could be a function */
 104 # define isascii(c) (!(c & 0200))
 105 #endif
 106
 107 /*
 108  * Resolver state default settings.
 109  */
 110
 111 /*
 112  * Set up default settings.  If the configuration file exist, the values
 113  * there will have precedence.  Otherwise, the server address is set to
 114  * INADDR_ANY and the default domain name comes from the gethostname().
 115  *
 116  * An interrim version of this code (BIND 4.9, pre-4.4BSD) used 127.0.0.1
 117  * rather than INADDR_ANY ("0.0.0.0") as the default name server address
 118  * since it was noted that INADDR_ANY actually meant ``the first interface
 119  * you "ifconfig"'d at boot time'' and if this was a SLIP or PPP interface,
 120  * it had to be "up" in order for you to reach your own name server.  It
 121  * was later decided that since the recommended practice is to always
 122  * install local static routes through 127.0.0.1 for all your network
 123  * interfaces, that we could solve this problem without a code change.
 124  *
 125  * The configuration file should always be used, since it is the only way
 126  * to specify a default domain.  If you are running a server on your local
 127  * machine, you should say "nameserver 0.0.0.0" or "nameserver 127.0.0.1"
 128  * in the configuration file.
 129  *
 130  * Return 0 if completes successfully, -1 on error
 131  */
 132 int
 133 res_ninit(res_state statp) {
 134         extern int __res_vinit(res_state, int);
 135
 136         return (__res_vinit(statp, 0));
 137 }
 138
 139 /* This function has to be reachable by res_data.c but not publically. */
 140 int
 141 __res_vinit(res_state statp, int preinit) {
 142         register FILE *fp;
 143         register char *cp, **pp;
 144         register int n;
 145         char buf[BUFSIZ];
 146         int nserv = 0;    /* number of nameserver records read from file */
 147 #ifdef _LIBC
 148         int nservall = 0; /* number of NS records read, nserv IPv4 only */
 149 #endif
 150         int haveenv = 0;
 151         int havesearch = 0;
 152 #ifdef RESOLVSORT
 153         int nsort = 0;
 154         char *net;
 155 #endif
 156 #ifndef RFC1535
 157         int dots;
 158 #endif
 159
 160         if (!preinit) {
 161                 statp->retrans = RES_TIMEOUT;
 162                 statp->retry = RES_DFLRETRY;
 163                 statp->options = RES_DEFAULT;
 164                 statp->id = res_randomid();
 165         }
 166
 167 #ifdef USELOOPBACK
 168         statp->nsaddr.sin_addr = inet_makeaddr(IN_LOOPBACKNET, 1);
 169 #else
 170         statp->nsaddr.sin_addr.s_addr = INADDR_ANY;
 171 #endif
 172         statp->nsaddr.sin_family = AF_INET;
 173         statp->nsaddr.sin_port = htons(NAMESERVER_PORT);
 174         statp->nscount = 1;
 175         statp->ndots = 1;
 176         statp->pfcode = 0;
 177         statp->_vcsock = -1;
 178         statp->_flags = 0;
 179         statp->qhook = NULL;
 180         statp->rhook = NULL;
 181         statp->_u._ext.nsinit = 0;
 182         statp->_u._ext.nscount = 0;
 183 #ifdef _LIBC
 184         statp->_u._ext.nscount6 = 0;
 185         for (n = 0; n < MAXNS; n++)
 186             statp->_u._ext.nsaddrs[n] = NULL;
 187 #endif
 188
 189         /* Allow user to override the local domain definition */
 190         if ((cp = getenv("LOCALDOMAIN")) != NULL) {
 191                 (void)strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
 192                 statp->defdname[sizeof(statp->defdname) - 1] = '\0';
 193                 haveenv++;
 194
 195                 /*
 196                  * Set search list to be blank-separated strings
 197                  * from rest of env value.  Permits users of LOCALDOMAIN
 198                  * to still have a search list, and anyone to set the
 199                  * one that they want to use as an individual (even more
 200                  * important now that the rfc1535 stuff restricts searches)
 201                  */
 202                 cp = statp->defdname;
 203                 pp = statp->dnsrch;
 204                 *pp++ = cp;
 205                 for (n = 0; *cp && pp < statp->dnsrch + MAXDNSRCH; cp++) {
 206                         if (*cp == '\n')        /* silly backwards compat */
 207                                 break;
 208                         else if (*cp == ' ' || *cp == '\t') {
 209                                 *cp = 0;
 210                                 n = 1;
 211                         } else if (n) {
 212                                 *pp++ = cp;
 213                                 n = 0;
 214                                 havesearch = 1;
 215                         }
 216                 }
 217                 /* null terminate last domain if there are excess */
 218                 while (*cp != '\0' && *cp != ' ' && *cp != '\t' && *cp != '\n')
 219                         cp++;
 220                 *cp = '\0';
 221                 *pp++ = 0;
 222         }
 223
 224 #define MATCH(line, name) \
 225         (!strncmp(line, name, sizeof(name) - 1) && \
 226         (line[sizeof(name) - 1] == ' ' || \
 227          line[sizeof(name) - 1] == '\t'))
 228
 229         if ((fp = fopen(_PATH_RESCONF, "r")) != NULL) {
 230                 /* No threads use this stream.  */
 231                 __fsetlocking (fp, FSETLOCKING_BYCALLER);
 232             /* read the config file */
 233             while (fgets_unlocked(buf, sizeof(buf), fp) != NULL) {
 234                 /* skip comments */
 235                 if (*buf == ';' || *buf == '#')
 236                         continue;
 237                 /* read default domain name */
 238                 if (MATCH(buf, "domain")) {
 239                     if (haveenv)        /* skip if have from environ */
 240                             continue;
 241                     cp = buf + sizeof("domain") - 1;
 242                     while (*cp == ' ' || *cp == '\t')
 243                             cp++;
 244                     if ((*cp == '\0') || (*cp == '\n'))
 245                             continue;
 246                     strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
 247                     statp->defdname[sizeof(statp->defdname) - 1] = '\0';
 248                     if ((cp = strpbrk(statp->defdname, " \t\n")) != NULL)
 249                             *cp = '\0';
 250                     havesearch = 0;
 251                     continue;
 252                 }
 253                 /* set search list */
 254                 if (MATCH(buf, "search")) {
 255                     if (haveenv)        /* skip if have from environ */
 256                             continue;
 257                     cp = buf + sizeof("search") - 1;
 258                     while (*cp == ' ' || *cp == '\t')
 259                             cp++;
 260                     if ((*cp == '\0') || (*cp == '\n'))
 261                             continue;
 262                     strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
 263                     statp->defdname[sizeof(statp->defdname) - 1] = '\0';
 264                     if ((cp = strchr(statp->defdname, '\n')) != NULL)
 265                             *cp = '\0';
 266                     /*
 267                      * Set search list to be blank-separated strings
 268                      * on rest of line.
 269                      */
 270                     cp = statp->defdname;
 271                     pp = statp->dnsrch;
 272                     *pp++ = cp;
 273                     for (n = 0; *cp && pp < statp->dnsrch + MAXDNSRCH; cp++) {
 274                             if (*cp == ' ' || *cp == '\t') {
 275                                     *cp = 0;
 276                                     n = 1;
 277                             } else if (n) {
 278                                     *pp++ = cp;
 279                                     n = 0;
 280                             }
 281                     }
 282                     /* null terminate last domain if there are excess */
 283                     while (*cp != '\0' && *cp != ' ' && *cp != '\t')
 284                             cp++;
 285                     *cp = '\0';
 286                     *pp++ = 0;
 287                     havesearch = 1;
 288                     continue;
 289                 }
 290                 /* read nameservers to query */
 291 #ifdef _LIBC
 292                 if (MATCH(buf, "nameserver") && nservall < MAXNS) {
 293 #else
 294                 if (MATCH(buf, "nameserver") && nserv < MAXNS) {
 295 #endif
 296                     struct in_addr a;
 297
 298                     cp = buf + sizeof("nameserver") - 1;
 299                     while (*cp == ' ' || *cp == '\t')
 300                         cp++;
 301                     if ((*cp != '\0') && (*cp != '\n')
 302                         && __inet_aton(cp, &a)) {
 303                         statp->nsaddr_list[nserv].sin_addr = a;
 304                         statp->nsaddr_list[nserv].sin_family = AF_INET;
 305                         statp->nsaddr_list[nserv].sin_port =
 306                                 htons(NAMESERVER_PORT);
 307                         nserv++;
 308 #ifdef _LIBC
 309                         nservall++;
 310                     } else {
 311                         struct in6_addr a6;
 312                         char *el;
 313
 314                         if ((el = strchr(cp, '\n')) != NULL)
 315                             *el = '\0';
 316                         if ((*cp != '\0') &&
 317                             (inet_pton(AF_INET6, cp, &a6) > 0)) {
 318                             struct sockaddr_in6 *sa6;
 319
 320                             sa6 = malloc(sizeof(*sa6));
 321                             if (sa6 != NULL) {
 322                                 sa6->sin6_addr = a6;
 323                                 sa6->sin6_family = AF_INET6;
 324                                 sa6->sin6_port = htons(NAMESERVER_PORT);
 325                                 statp->_u._ext.nsaddrs[nservall] = sa6;
 326                                 statp->_u._ext.nstimes[nservall] = RES_MAXTIME;
 327                                 statp->_u._ext.nssocks[nservall] = -1;
 328                                 nservall++;
 329                             }
 330                         }
 331 #endif
 332                     }
 333                     continue;
 334                 }
 335 #ifdef RESOLVSORT
 336                 if (MATCH(buf, "sortlist")) {
 337                     struct in_addr a;
 338
 339                     cp = buf + sizeof("sortlist") - 1;
 340                     while (nsort < MAXRESOLVSORT) {
 341                         while (*cp == ' ' || *cp == '\t')
 342                             cp++;
 343                         if (*cp == '\0' || *cp == '\n' || *cp == ';')
 344                             break;
 345                         net = cp;
 346                         while (*cp && !ISSORTMASK(*cp) && *cp != ';' &&
 347                                isascii(*cp) && !isspace(*cp))
 348                                 cp++;
 349                         n = *cp;
 350                         *cp = 0;
 351                         if (__inet_aton(net, &a)) {
 352                             statp->sort_list[nsort].addr = a;
 353                             if (ISSORTMASK(n)) {
 354                                 *cp++ = n;
 355                                 net = cp;
 356                                 while (*cp && *cp != ';' &&
 357                                         isascii(*cp) && !isspace(*cp))
 358                                     cp++;
 359                                 n = *cp;
 360                                 *cp = 0;
 361                                 if (__inet_aton(net, &a)) {
 362                                     statp->sort_list[nsort].mask = a.s_addr;
 363                                 } else {
 364                                     statp->sort_list[nsort].mask =
 365                                         net_mask(statp->sort_list[nsort].addr);
 366                                 }
 367                             } else {
 368                                 statp->sort_list[nsort].mask =
 369                                     net_mask(statp->sort_list[nsort].addr);
 370                             }
 371                             nsort++;
 372                         }
 373                         *cp = n;
 374                     }
 375                     continue;
 376                 }
 377 #endif
 378                 if (MATCH(buf, "options")) {
 379                     res_setoptions(statp, buf + sizeof("options") - 1, "conf");
 380                     continue;
 381                 }
 382             }
 383             if (nserv > 1)
 384                 statp->nscount = nserv;
 385 #ifdef _LIBC
 386             if (nservall - nserv > 0)
 387                 statp->_u._ext.nscount6 = nservall - nserv;
 388 #endif
 389 #ifdef RESOLVSORT
 390             statp->nsort = nsort;
 391 #endif
 392             (void) fclose(fp);
 393         }
 394         if (statp->defdname[0] == 0 &&
 395             __gethostname(buf, sizeof(statp->defdname) - 1) == 0 &&
 396             (cp = strchr(buf, '.')) != NULL)
 397                 strcpy(statp->defdname, cp + 1);
 398
 399         /* find components of local domain that might be searched */
 400         if (havesearch == 0) {
 401                 pp = statp->dnsrch;
 402                 *pp++ = statp->defdname;
 403                 *pp = NULL;
 404
 405 #ifndef RFC1535
 406                 dots = 0;
 407                 for (cp = statp->defdname; *cp; cp++)
 408                         dots += (*cp == '.');
 409
 410                 cp = statp->defdname;
 411                 while (pp < statp->dnsrch + MAXDFLSRCH) {
 412                         if (dots < LOCALDOMAINPARTS)
 413                                 break;
 414                         cp = __rawmemchr(cp, '.') + 1;    /* we know there is one */
 415                         *pp++ = cp;
 416                         dots--;
 417                 }
 418                 *pp = NULL;
 419 #ifdef DEBUG
 420                 if (statp->options & RES_DEBUG) {
 421                         printf(";; res_init()... default dnsrch list:\n");
 422                         for (pp = statp->dnsrch; *pp; pp++)
 423                                 printf(";;\t%s\n", *pp);
 424                         printf(";;\t..END..\n");
 425                 }
 426 #endif
 427 #endif /* !RFC1535 */
 428         }
 429
 430         if ((cp = getenv("RES_OPTIONS")) != NULL)
 431                 res_setoptions(statp, cp, "env");
 432         statp->options |= RES_INIT;
 433         return (0);
 434 }
 435
 436 static void
 437 internal_function
 438 res_setoptions(res_state statp, const char *options, const char *source) {
 439         const char *cp = options;
 440         int i;
 441
 442 #ifdef DEBUG
 443         if (statp->options & RES_DEBUG)
 444                 printf(";; res_setoptions(\"%s\", \"%s\")...\n",
 445                        options, source);
 446 #endif
 447         while (*cp) {
 448                 /* skip leading and inner runs of spaces */
 449                 while (*cp == ' ' || *cp == '\t')
 450                         cp++;
 451                 /* search for and process individual options */
 452                 if (!strncmp(cp, "ndots:", sizeof("ndots:") - 1)) {
 453                         i = atoi(cp + sizeof("ndots:") - 1);
 454                         if (i <= RES_MAXNDOTS)
 455                                 statp->ndots = i;
 456                         else
 457                                 statp->ndots = RES_MAXNDOTS;
 458 #ifdef DEBUG
 459                         if (statp->options & RES_DEBUG)
 460                                 printf(";;\tndots=%d\n", statp->ndots);
 461 #endif
 462                 } else if (!strncmp(cp, "timeout:", sizeof("timeout:") - 1)) {
 463                         i = atoi(cp + sizeof("timeout:") - 1);
 464                         if (i <= RES_MAXRETRANS)
 465                                 statp->retrans = i;
 466                         else
 467                                 statp->retrans = RES_MAXRETRANS;
 468                 } else if (!strncmp(cp, "attempts:", sizeof("attempts:") - 1)){
 469                         i = atoi(cp + sizeof("attempts:") - 1);
 470                         if (i <= RES_MAXRETRY)
 471                                 statp->retry = i;
 472                         else
 473                                 statp->retry = RES_MAXRETRY;
 474                 } else if (!strncmp(cp, "debug", sizeof("debug") - 1)) {
 475 #ifdef DEBUG
 476                         if (!(statp->options & RES_DEBUG)) {
 477                                 printf(";; res_setoptions(\"%s\", \"%s\")..\n",
 478                                        options, source);
 479                                 statp->options |= RES_DEBUG;
 480                         }
 481                         printf(";;\tdebug\n");
 482 #endif
 483                 } else if (!strncmp(cp, "inet6", sizeof("inet6") - 1)) {
 484                         statp->options |= RES_USE_INET6;
 485                 } else if (!strncmp(cp, "rotate", sizeof("rotate") - 1)) {
 486                         statp->options |= RES_ROTATE;
 487                 } else if (!strncmp(cp, "no-check-names",
 488                                     sizeof("no-check-names") - 1)) {
 489                         statp->options |= RES_NOCHECKNAME;
 490                 } else {
 491                         /* XXX - print a warning here? */
 492                 }
 493                 /* skip to next run of spaces */
 494                 while (*cp && *cp != ' ' && *cp != '\t')
 495                         cp++;
 496         }
 497 }
 498
 499 #ifdef RESOLVSORT
 500 /* XXX - should really support CIDR which means explicit masks always. */
 501 static u_int32_t
 502 net_mask(in)            /* XXX - should really use system's version of this */
 503         struct in_addr in;
 504 {
 505         register u_int32_t i = ntohl(in.s_addr);
 506
 507         if (IN_CLASSA(i))
 508                 return (htonl(IN_CLASSA_NET));
 509         else if (IN_CLASSB(i))
 510                 return (htonl(IN_CLASSB_NET));
 511         return (htonl(IN_CLASSC_NET));
 512 }
 513 #endif
 514
 515 u_int
 516 res_randomid(void) {
 517         struct timeval now;
 518
 519         __gettimeofday(&now, NULL);
 520         return (0xffff & (now.tv_sec ^ now.tv_usec ^ __getpid()));
 521 }
 522
 523 /*
 524  * This routine is for closing the socket if a virtual circuit is used and
 525  * the program wants to close it.  This provides support for endhostent()
 526  * which expects to close the socket.
 527  *
 528  * This routine is not expected to be user visible.
 529  */
 530 void
 531 res_nclose(res_state statp) {
 532         int ns;
 533
 534         if (statp->_vcsock >= 0) {
 535                 (void) __close(statp->_vcsock);
 536                 statp->_vcsock = -1;
 537                 statp->_flags &= ~(RES_F_VC | RES_F_CONN);
 538         }
 539 #ifdef _LIBC
 540         for (ns = 0; ns < statp->_u._ext.nscount + statp->_u._ext.nscount6;
 541              ns++)
 542 #else
 543         for (ns = 0; ns < statp->_u._ext.nscount; ns++)
 544 #endif
 545         {
 546                 if (statp->_u._ext.nssocks[ns] != -1) {
 547                         (void) __close(statp->_u._ext.nssocks[ns]);
 548                         statp->_u._ext.nssocks[ns] = -1;
 549                 }
 550         }
 551         statp->_u._ext.nsinit = 0;
 552 }