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[] = "$Id$";
  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 <stdlib.h>
  85 #include <string.h>
  86 #include <unistd.h>
  87
  88 /* Options.  Should all be left alone. */
  89 #define RESOLVSORT
  90 #define RFC1535
  91 #undef DEBUG
  92
  93 static void
  94 res_setoptions (res_state statp, const char *options, const char *source)
  95      internal_function;
  96
  97
  98 #ifdef RESOLVSORT
  99 static const char sort_mask[] = "/&";
 100 #define ISSORTMASK(ch) (strchr(sort_mask, ch) != NULL)
 101 static u_int32_t net_mask __P((struct in_addr));
 102 #endif
 103
 104 #if !defined(isascii)   /* XXX - could be a function */
 105 # define isascii(c) (!(c & 0200))
 106 #endif
 107
 108 /*
 109  * Resolver state default settings.
 110  */
 111
 112 /*
 113  * Set up default settings.  If the configuration file exist, the values
 114  * there will have precedence.  Otherwise, the server address is set to
 115  * INADDR_ANY and the default domain name comes from the gethostname().
 116  *
 117  * An interrim version of this code (BIND 4.9, pre-4.4BSD) used 127.0.0.1
 118  * rather than INADDR_ANY ("0.0.0.0") as the default name server address
 119  * since it was noted that INADDR_ANY actually meant ``the first interface
 120  * you "ifconfig"'d at boot time'' and if this was a SLIP or PPP interface,
 121  * it had to be "up" in order for you to reach your own name server.  It
 122  * was later decided that since the recommended practice is to always
 123  * install local static routes through 127.0.0.1 for all your network
 124  * interfaces, that we could solve this problem without a code change.
 125  *
 126  * The configuration file should always be used, since it is the only way
 127  * to specify a default domain.  If you are running a server on your local
 128  * machine, you should say "nameserver 0.0.0.0" or "nameserver 127.0.0.1"
 129  * in the configuration file.
 130  *
 131  * Return 0 if completes successfully, -1 on error
 132  */
 133 int
 134 res_ninit(res_state statp) {
 135         extern int __res_vinit(res_state, int);
 136
 137         return (__res_vinit(statp, 0));
 138 }
 139
 140 /* This function has to be reachable by res_data.c but not publically. */
 141 int
 142 __res_vinit(res_state statp, int preinit) {
 143         register FILE *fp;
 144         register char *cp, **pp;
 145         register int n;
 146         char buf[BUFSIZ];
 147         int nserv = 0;    /* number of nameserver records read from file */
 148         int haveenv = 0;
 149         int havesearch = 0;
 150 #ifdef RESOLVSORT
 151         int nsort = 0;
 152         char *net;
 153 #endif
 154 #ifndef RFC1535
 155         int dots;
 156 #endif
 157
 158         if (!preinit) {
 159                 statp->retrans = RES_TIMEOUT;
 160                 statp->retry = RES_DFLRETRY;
 161                 statp->options = RES_DEFAULT;
 162                 statp->id = res_randomid();
 163         }
 164
 165 #ifdef USELOOPBACK
 166         statp->nsaddr.sin_addr = inet_makeaddr(IN_LOOPBACKNET, 1);
 167 #else
 168         statp->nsaddr.sin_addr.s_addr = INADDR_ANY;
 169 #endif
 170         statp->nsaddr.sin_family = AF_INET;
 171         statp->nsaddr.sin_port = htons(NAMESERVER_PORT);
 172         statp->nscount = 1;
 173         statp->ndots = 1;
 174         statp->pfcode = 0;
 175         statp->_sock = -1;
 176         statp->_flags = 0;
 177         statp->qhook = NULL;
 178         statp->rhook = NULL;
 179
 180         /* Allow user to override the local domain definition */
 181         if ((cp = __secure_getenv("LOCALDOMAIN")) != NULL) {
 182                 (void)strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
 183                 statp->defdname[sizeof(statp->defdname) - 1] = '\0';
 184                 haveenv++;
 185
 186                 /*
 187                  * Set search list to be blank-separated strings
 188                  * from rest of env value.  Permits users of LOCALDOMAIN
 189                  * to still have a search list, and anyone to set the
 190                  * one that they want to use as an individual (even more
 191                  * important now that the rfc1535 stuff restricts searches)
 192                  */
 193                 cp = statp->defdname;
 194                 pp = statp->dnsrch;
 195                 *pp++ = cp;
 196                 for (n = 0; *cp && pp < statp->dnsrch + MAXDNSRCH; cp++) {
 197                         if (*cp == '\n')        /* silly backwards compat */
 198                                 break;
 199                         else if (*cp == ' ' || *cp == '\t') {
 200                                 *cp = 0;
 201                                 n = 1;
 202                         } else if (n) {
 203                                 *pp++ = cp;
 204                                 n = 0;
 205                                 havesearch = 1;
 206                         }
 207                 }
 208                 /* null terminate last domain if there are excess */
 209                 while (*cp != '\0' && *cp != ' ' && *cp != '\t' && *cp != '\n')
 210                         cp++;
 211                 *cp = '\0';
 212                 *pp++ = 0;
 213         }
 214
 215 #define MATCH(line, name) \
 216         (!strncmp(line, name, sizeof(name) - 1) && \
 217         (line[sizeof(name) - 1] == ' ' || \
 218          line[sizeof(name) - 1] == '\t'))
 219
 220         if ((fp = fopen(_PATH_RESCONF, "r")) != NULL) {
 221             /* read the config file */
 222             while (fgets_unlocked(buf, sizeof(buf), fp) != NULL) {
 223                 /* skip comments */
 224                 if (*buf == ';' || *buf == '#')
 225                         continue;
 226                 /* read default domain name */
 227                 if (MATCH(buf, "domain")) {
 228                     if (haveenv)        /* skip if have from environ */
 229                             continue;
 230                     cp = buf + sizeof("domain") - 1;
 231                     while (*cp == ' ' || *cp == '\t')
 232                             cp++;
 233                     if ((*cp == '\0') || (*cp == '\n'))
 234                             continue;
 235                     strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
 236                     statp->defdname[sizeof(statp->defdname) - 1] = '\0';
 237                     if ((cp = strpbrk(statp->defdname, " \t\n")) != NULL)
 238                             *cp = '\0';
 239                     havesearch = 0;
 240                     continue;
 241                 }
 242                 /* set search list */
 243                 if (MATCH(buf, "search")) {
 244                     if (haveenv)        /* skip if have from environ */
 245                             continue;
 246                     cp = buf + sizeof("search") - 1;
 247                     while (*cp == ' ' || *cp == '\t')
 248                             cp++;
 249                     if ((*cp == '\0') || (*cp == '\n'))
 250                             continue;
 251                     strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
 252                     statp->defdname[sizeof(statp->defdname) - 1] = '\0';
 253                     if ((cp = strchr(statp->defdname, '\n')) != NULL)
 254                             *cp = '\0';
 255                     /*
 256                      * Set search list to be blank-separated strings
 257                      * on rest of line.
 258                      */
 259                     cp = statp->defdname;
 260                     pp = statp->dnsrch;
 261                     *pp++ = cp;
 262                     for (n = 0; *cp && pp < statp->dnsrch + MAXDNSRCH; cp++) {
 263                             if (*cp == ' ' || *cp == '\t') {
 264                                     *cp = 0;
 265                                     n = 1;
 266                             } else if (n) {
 267                                     *pp++ = cp;
 268                                     n = 0;
 269                             }
 270                     }
 271                     /* null terminate last domain if there are excess */
 272                     while (*cp != '\0' && *cp != ' ' && *cp != '\t')
 273                             cp++;
 274                     *cp = '\0';
 275                     *pp++ = 0;
 276                     havesearch = 1;
 277                     continue;
 278                 }
 279                 /* read nameservers to query */
 280                 if (MATCH(buf, "nameserver") && nserv < MAXNS) {
 281                     struct in_addr a;
 282
 283                     cp = buf + sizeof("nameserver") - 1;
 284                     while (*cp == ' ' || *cp == '\t')
 285                         cp++;
 286                     if ((*cp != '\0') && (*cp != '\n') && inet_aton(cp, &a)) {
 287                         statp->nsaddr_list[nserv].sin_addr = a;
 288                         statp->nsaddr_list[nserv].sin_family = AF_INET;
 289                         statp->nsaddr_list[nserv].sin_port =
 290                                 htons(NAMESERVER_PORT);
 291                         nserv++;
 292                     }
 293                     continue;
 294                 }
 295 #ifdef RESOLVSORT
 296                 if (MATCH(buf, "sortlist")) {
 297                     struct in_addr a;
 298
 299                     cp = buf + sizeof("sortlist") - 1;
 300                     while (nsort < MAXRESOLVSORT) {
 301                         while (*cp == ' ' || *cp == '\t')
 302                             cp++;
 303                         if (*cp == '\0' || *cp == '\n' || *cp == ';')
 304                             break;
 305                         net = cp;
 306                         while (*cp && !ISSORTMASK(*cp) && *cp != ';' &&
 307                                isascii(*cp) && !isspace(*cp))
 308                                 cp++;
 309                         n = *cp;
 310                         *cp = 0;
 311                         if (inet_aton(net, &a)) {
 312                             statp->sort_list[nsort].addr = a;
 313                             if (ISSORTMASK(n)) {
 314                                 *cp++ = n;
 315                                 net = cp;
 316                                 while (*cp && *cp != ';' &&
 317                                         isascii(*cp) && !isspace(*cp))
 318                                     cp++;
 319                                 n = *cp;
 320                                 *cp = 0;
 321                                 if (inet_aton(net, &a)) {
 322                                     statp->sort_list[nsort].mask = a.s_addr;
 323                                 } else {
 324                                     statp->sort_list[nsort].mask =
 325                                         net_mask(statp->sort_list[nsort].addr);
 326                                 }
 327                             } else {
 328                                 statp->sort_list[nsort].mask =
 329                                     net_mask(statp->sort_list[nsort].addr);
 330                             }
 331                             nsort++;
 332                         }
 333                         *cp = n;
 334                     }
 335                     continue;
 336                 }
 337 #endif
 338                 if (MATCH(buf, "options")) {
 339                     res_setoptions(statp, buf + sizeof("options") - 1, "conf");
 340                     continue;
 341                 }
 342             }
 343             if (nserv > 1)
 344                 statp->nscount = nserv;
 345 #ifdef RESOLVSORT
 346             statp->nsort = nsort;
 347 #endif
 348             (void) fclose(fp);
 349         }
 350         if (statp->defdname[0] == 0 &&
 351             __gethostname(buf, sizeof(statp->defdname) - 1) == 0 &&
 352             (cp = strchr(buf, '.')) != NULL)
 353                 strcpy(statp->defdname, cp + 1);
 354
 355         /* find components of local domain that might be searched */
 356         if (havesearch == 0) {
 357                 pp = statp->dnsrch;
 358                 *pp++ = statp->defdname;
 359                 *pp = NULL;
 360
 361 #ifndef RFC1535
 362                 dots = 0;
 363                 for (cp = statp->defdname; *cp; cp++)
 364                         dots += (*cp == '.');
 365
 366                 cp = statp->defdname;
 367                 while (pp < statp->dnsrch + MAXDFLSRCH) {
 368                         if (dots < LOCALDOMAINPARTS)
 369                                 break;
 370                         cp = __rawmemchr(cp, '.') + 1;    /* we know there is one */
 371                         *pp++ = cp;
 372                         dots--;
 373                 }
 374                 *pp = NULL;
 375 #ifdef DEBUG
 376                 if (statp->options & RES_DEBUG) {
 377                         printf(";; res_init()... default dnsrch list:\n");
 378                         for (pp = statp->dnsrch; *pp; pp++)
 379                                 printf(";;\t%s\n", *pp);
 380                         printf(";;\t..END..\n");
 381                 }
 382 #endif
 383 #endif /* !RFC1535 */
 384         }
 385
 386         if ((cp = __secure_getenv("RES_OPTIONS")) != NULL)
 387                 res_setoptions(statp, cp, "env");
 388         statp->options |= RES_INIT;
 389         return (0);
 390 }
 391
 392 static void
 393 internal_function
 394 res_setoptions(res_state statp, const char *options, const char *source)
 395 {
 396         const char *cp = options;
 397         int i;
 398
 399 #ifdef DEBUG
 400         if (statp->options & RES_DEBUG)
 401                 printf(";; res_setoptions(\"%s\", \"%s\")...\n",
 402                        options, source);
 403 #endif
 404         while (*cp) {
 405                 /* skip leading and inner runs of spaces */
 406                 while (*cp == ' ' || *cp == '\t')
 407                         cp++;
 408                 /* search for and process individual options */
 409                 if (!strncmp(cp, "ndots:", sizeof("ndots:") - 1)) {
 410                         i = atoi(cp + sizeof("ndots:") - 1);
 411                         if (i <= RES_MAXNDOTS)
 412                                 statp->ndots = i;
 413                         else
 414                                 statp->ndots = RES_MAXNDOTS;
 415 #ifdef DEBUG
 416                         if (statp->options & RES_DEBUG)
 417                                 printf(";;\tndots=%d\n", statp->ndots);
 418 #endif
 419                 } else if (!strncmp(cp, "timeout:", sizeof("timeout:") - 1)) {
 420                         i = atoi(cp + sizeof("timeout:") - 1);
 421                         if (i <= RES_MAXRETRANS)
 422                                 statp->retrans = i;
 423                         else
 424                                 statp->retrans = RES_MAXRETRANS;
 425                 } else if (!strncmp(cp, "attempts:", sizeof("attempts:") - 1)){
 426                         i = atoi(cp + sizeof("attempts:") - 1);
 427                         if (i <= RES_MAXRETRY)
 428                                 statp->retry = i;
 429                         else
 430                                 statp->retry = RES_MAXRETRY;
 431                 } else if (!strncmp(cp, "debug", sizeof("debug") - 1)) {
 432 #ifdef DEBUG
 433                         if (!(statp->options & RES_DEBUG)) {
 434                                 printf(";; res_setoptions(\"%s\", \"%s\")..\n",
 435                                        options, source);
 436                                 statp->options |= RES_DEBUG;
 437                         }
 438                         printf(";;\tdebug\n");
 439 #endif
 440                 } else if (!strncmp(cp, "inet6", sizeof("inet6") - 1)) {
 441                         statp->options |= RES_USE_INET6;
 442                 } else if (!strncmp(cp, "rotate", sizeof("rotate") - 1)) {
 443                         statp->options |= RES_ROTATE;
 444                 } else if (!strncmp(cp, "no-check-names",
 445                                     sizeof("no-check-names") - 1)) {
 446                         statp->options |= RES_NOCHECKNAME;
 447                 } else {
 448                         /* XXX - print a warning here? */
 449                 }
 450                 /* skip to next run of spaces */
 451                 while (*cp && *cp != ' ' && *cp != '\t')
 452                         cp++;
 453         }
 454 }
 455
 456 #ifdef RESOLVSORT
 457 /* XXX - should really support CIDR which means explicit masks always. */
 458 static u_int32_t
 459 net_mask(in)            /* XXX - should really use system's version of this */
 460         struct in_addr in;
 461 {
 462         register u_int32_t i = ntohl(in.s_addr);
 463
 464         if (IN_CLASSA(i))
 465                 return (htonl(IN_CLASSA_NET));
 466         else if (IN_CLASSB(i))
 467                 return (htonl(IN_CLASSB_NET));
 468         return (htonl(IN_CLASSC_NET));
 469 }
 470 #endif
 471
 472 u_int
 473 res_randomid(void) {
 474         struct timeval now;
 475
 476         __gettimeofday(&now, NULL);
 477         return (0xffff & (now.tv_sec ^ now.tv_usec ^ __getpid()));
 478 }