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 <ctype.h>
  73 #include <netdb.h>
  74 #include <resolv.h>
  75 #include <stdio.h>
  76 #include <stdio_ext.h>
  77 #include <stdlib.h>
  78 #include <string.h>
  79 #include <unistd.h>
  80 #include <stdint.h>
  81 #include <arpa/inet.h>
  82 #include <arpa/nameser.h>
  83 #include <net/if.h>
  84 #include <netinet/in.h>
  85 #include <sys/param.h>
  86 #include <sys/socket.h>
  87 #include <sys/time.h>
  88 #include <sys/types.h>
  89
  90 #include <not-cancel.h>
  91
  92 /* Options.  Should all be left alone. */
  93 #define RESOLVSORT
  94 #define RFC1535
  95 /* #undef DEBUG */
  96
  97 static void res_setoptions (res_state, const char *, const char *)
  98      internal_function;
  99
 100 #ifdef RESOLVSORT
 101 static const char sort_mask_chars[] = "/&";
 102 #define ISSORTMASK(ch) (strchr(sort_mask_chars, ch) != NULL)
 103 static u_int32_t net_mask (struct in_addr) __THROW;
 104 #endif
 105
 106 #if !defined(isascii)   /* XXX - could be a function */
 107 # define isascii(c) (!(c & 0200))
 108 #endif
 109
 110 #ifdef _LIBC
 111 unsigned long long int __res_initstamp attribute_hidden;
 112 #endif
 113
 114 /*
 115  * Resolver state default settings.
 116  */
 117
 118 /*
 119  * Set up default settings.  If the configuration file exist, the values
 120  * there will have precedence.  Otherwise, the server address is set to
 121  * INADDR_ANY and the default domain name comes from the gethostname().
 122  *
 123  * An interrim version of this code (BIND 4.9, pre-4.4BSD) used 127.0.0.1
 124  * rather than INADDR_ANY ("0.0.0.0") as the default name server address
 125  * since it was noted that INADDR_ANY actually meant ``the first interface
 126  * you "ifconfig"'d at boot time'' and if this was a SLIP or PPP interface,
 127  * it had to be "up" in order for you to reach your own name server.  It
 128  * was later decided that since the recommended practice is to always
 129  * install local static routes through 127.0.0.1 for all your network
 130  * interfaces, that we could solve this problem without a code change.
 131  *
 132  * The configuration file should always be used, since it is the only way
 133  * to specify a default domain.  If you are running a server on your local
 134  * machine, you should say "nameserver 0.0.0.0" or "nameserver 127.0.0.1"
 135  * in the configuration file.
 136  *
 137  * Return 0 if completes successfully, -1 on error
 138  */
 139 int
 140 res_ninit(res_state statp) {
 141         extern int __res_vinit(res_state, int);
 142
 143         return (__res_vinit(statp, 0));
 144 }
 145 #ifdef _LIBC
 146 libc_hidden_def (__res_ninit)
 147 #endif
 148
 149 /* This function has to be reachable by res_data.c but not publically. */
 150 int
 151 __res_vinit(res_state statp, int preinit) {
 152         FILE *fp;
 153         char *cp, **pp;
 154         int n;
 155         char buf[BUFSIZ];
 156         int nserv = 0;    /* number of nameservers read from file */
 157         int have_serv6 = 0;
 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 #ifdef _LIBC
 168         statp->_u._ext.initstamp = __res_initstamp;
 169 #endif
 170
 171         if (!preinit) {
 172                 statp->retrans = RES_TIMEOUT;
 173                 statp->retry = RES_DFLRETRY;
 174                 statp->options = RES_DEFAULT;
 175                 statp->id = res_randomid();
 176         }
 177
 178         statp->nscount = 0;
 179         statp->ndots = 1;
 180         statp->pfcode = 0;
 181         statp->_vcsock = -1;
 182         statp->_flags = 0;
 183         statp->qhook = NULL;
 184         statp->rhook = NULL;
 185         statp->_u._ext.nscount = 0;
 186         for (n = 0; n < MAXNS; n++)
 187             statp->_u._ext.nsaddrs[n] = NULL;
 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, "rce")) != 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                 if (MATCH(buf, "nameserver") && nserv < MAXNS) {
 292                     struct in_addr a;
 293
 294                     cp = buf + sizeof("nameserver") - 1;
 295                     while (*cp == ' ' || *cp == '\t')
 296                         cp++;
 297                     if ((*cp != '\0') && (*cp != '\n')
 298                         && __inet_aton(cp, &a)) {
 299                         statp->nsaddr_list[nserv].sin_addr = a;
 300                         statp->nsaddr_list[nserv].sin_family = AF_INET;
 301                         statp->nsaddr_list[nserv].sin_port =
 302                                 htons(NAMESERVER_PORT);
 303                         nserv++;
 304 #ifdef _LIBC
 305                     } else {
 306                         struct in6_addr a6;
 307                         char *el;
 308
 309                         if ((el = strpbrk(cp, " \t\n")) != NULL)
 310                             *el = '\0';
 311                         if ((el = strchr(cp, SCOPE_DELIMITER)) != NULL)
 312                             *el = '\0';
 313                         if ((*cp != '\0') &&
 314                             (__inet_pton(AF_INET6, cp, &a6) > 0)) {
 315                             struct sockaddr_in6 *sa6;
 316
 317                             sa6 = malloc(sizeof(*sa6));
 318                             if (sa6 != NULL) {
 319                                 sa6->sin6_family = AF_INET6;
 320                                 sa6->sin6_port = htons(NAMESERVER_PORT);
 321                                 sa6->sin6_flowinfo = 0;
 322                                 sa6->sin6_addr = a6;
 323
 324                                 if (__glibc_likely (el == NULL))
 325                                     sa6->sin6_scope_id = 0;
 326                                 else {
 327                                     int try_numericscope = 1;
 328                                     if (IN6_IS_ADDR_LINKLOCAL (&a6)
 329                                         || IN6_IS_ADDR_MC_LINKLOCAL (&a6)) {
 330                                         sa6->sin6_scope_id
 331                                           = __if_nametoindex (el + 1);
 332                                         if (sa6->sin6_scope_id != 0)
 333                                             try_numericscope = 0;
 334                                     }
 335
 336                                     if (try_numericscope) {
 337                                         char *end;
 338                                         sa6->sin6_scope_id
 339                                           = (uint32_t) strtoul (el + 1, &end,
 340                                                                 10);
 341                                         if (*end != '\0')
 342                                             sa6->sin6_scope_id = 0;
 343                                     }
 344                                 }
 345
 346                                 statp->nsaddr_list[nserv].sin_family = 0;
 347                                 statp->_u._ext.nsaddrs[nserv] = sa6;
 348                                 statp->_u._ext.nssocks[nserv] = -1;
 349                                 have_serv6 = 1;
 350                                 nserv++;
 351                             }
 352                         }
 353 #endif
 354                     }
 355                     continue;
 356                 }
 357 #ifdef RESOLVSORT
 358                 if (MATCH(buf, "sortlist")) {
 359                     struct in_addr a;
 360
 361                     cp = buf + sizeof("sortlist") - 1;
 362                     while (nsort < MAXRESOLVSORT) {
 363                         while (*cp == ' ' || *cp == '\t')
 364                             cp++;
 365                         if (*cp == '\0' || *cp == '\n' || *cp == ';')
 366                             break;
 367                         net = cp;
 368                         while (*cp && !ISSORTMASK(*cp) && *cp != ';' &&
 369                                isascii(*cp) && !isspace(*cp))
 370                                 cp++;
 371                         n = *cp;
 372                         *cp = 0;
 373                         if (__inet_aton(net, &a)) {
 374                             statp->sort_list[nsort].addr = a;
 375                             if (ISSORTMASK(n)) {
 376                                 *cp++ = n;
 377                                 net = cp;
 378                                 while (*cp && *cp != ';' &&
 379                                         isascii(*cp) && !isspace(*cp))
 380                                     cp++;
 381                                 n = *cp;
 382                                 *cp = 0;
 383                                 if (__inet_aton(net, &a)) {
 384                                     statp->sort_list[nsort].mask = a.s_addr;
 385                                 } else {
 386                                     statp->sort_list[nsort].mask =
 387                                         net_mask(statp->sort_list[nsort].addr);
 388                                 }
 389                             } else {
 390                                 statp->sort_list[nsort].mask =
 391                                     net_mask(statp->sort_list[nsort].addr);
 392                             }
 393                             nsort++;
 394                         }
 395                         *cp = n;
 396                     }
 397                     continue;
 398                 }
 399 #endif
 400                 if (MATCH(buf, "options")) {
 401                     res_setoptions(statp, buf + sizeof("options") - 1, "conf");
 402                     continue;
 403                 }
 404             }
 405             statp->nscount = nserv;
 406 #ifdef _LIBC
 407             if (have_serv6) {
 408                 /* We try IPv6 servers again.  */
 409                 statp->ipv6_unavail = false;
 410             }
 411 #endif
 412 #ifdef RESOLVSORT
 413             statp->nsort = nsort;
 414 #endif
 415             (void) fclose(fp);
 416         }
 417         if (__builtin_expect(statp->nscount == 0, 0)) {
 418             statp->nsaddr.sin_addr = __inet_makeaddr(IN_LOOPBACKNET, 1);
 419             statp->nsaddr.sin_family = AF_INET;
 420             statp->nsaddr.sin_port = htons(NAMESERVER_PORT);
 421             statp->nscount = 1;
 422         }
 423         if (statp->defdname[0] == 0 &&
 424             __gethostname(buf, sizeof(statp->defdname) - 1) == 0 &&
 425             (cp = strchr(buf, '.')) != NULL)
 426                 strcpy(statp->defdname, cp + 1);
 427
 428         /* find components of local domain that might be searched */
 429         if (havesearch == 0) {
 430                 pp = statp->dnsrch;
 431                 *pp++ = statp->defdname;
 432                 *pp = NULL;
 433
 434 #ifndef RFC1535
 435                 dots = 0;
 436                 for (cp = statp->defdname; *cp; cp++)
 437                         dots += (*cp == '.');
 438
 439                 cp = statp->defdname;
 440                 while (pp < statp->dnsrch + MAXDFLSRCH) {
 441                         if (dots < LOCALDOMAINPARTS)
 442                                 break;
 443                         cp = __rawmemchr(cp, '.') + 1;    /* we know there is one */
 444                         *pp++ = cp;
 445                         dots--;
 446                 }
 447                 *pp = NULL;
 448 #ifdef DEBUG
 449                 if (statp->options & RES_DEBUG) {
 450                         printf(";; res_init()... default dnsrch list:\n");
 451                         for (pp = statp->dnsrch; *pp; pp++)
 452                                 printf(";;\t%s\n", *pp);
 453                         printf(";;\t..END..\n");
 454                 }
 455 #endif
 456 #endif /* !RFC1535 */
 457         }
 458
 459         if ((cp = getenv("RES_OPTIONS")) != NULL)
 460                 res_setoptions(statp, cp, "env");
 461         statp->options |= RES_INIT;
 462         return (0);
 463 }
 464
 465 static void
 466 internal_function
 467 res_setoptions(res_state statp, const char *options, const char *source) {
 468         const char *cp = options;
 469         int i;
 470
 471 #ifdef DEBUG
 472         if (statp->options & RES_DEBUG)
 473                 printf(";; res_setoptions(\"%s\", \"%s\")...\n",
 474                        options, source);
 475 #endif
 476         while (*cp) {
 477                 /* skip leading and inner runs of spaces */
 478                 while (*cp == ' ' || *cp == '\t')
 479                         cp++;
 480                 /* search for and process individual options */
 481                 if (!strncmp(cp, "ndots:", sizeof("ndots:") - 1)) {
 482                         i = atoi(cp + sizeof("ndots:") - 1);
 483                         if (i <= RES_MAXNDOTS)
 484                                 statp->ndots = i;
 485                         else
 486                                 statp->ndots = RES_MAXNDOTS;
 487 #ifdef DEBUG
 488                         if (statp->options & RES_DEBUG)
 489                                 printf(";;\tndots=%d\n", statp->ndots);
 490 #endif
 491                 } else if (!strncmp(cp, "timeout:", sizeof("timeout:") - 1)) {
 492                         i = atoi(cp + sizeof("timeout:") - 1);
 493                         if (i <= RES_MAXRETRANS)
 494                                 statp->retrans = i;
 495                         else
 496                                 statp->retrans = RES_MAXRETRANS;
 497                 } else if (!strncmp(cp, "attempts:", sizeof("attempts:") - 1)){
 498                         i = atoi(cp + sizeof("attempts:") - 1);
 499                         if (i <= RES_MAXRETRY)
 500                                 statp->retry = i;
 501                         else
 502                                 statp->retry = RES_MAXRETRY;
 503                 } else if (!strncmp(cp, "debug", sizeof("debug") - 1)) {
 504 #ifdef DEBUG
 505                         if (!(statp->options & RES_DEBUG)) {
 506                                 printf(";; res_setoptions(\"%s\", \"%s\")..\n",
 507                                        options, source);
 508                                 statp->options |= RES_DEBUG;
 509                         }
 510                         printf(";;\tdebug\n");
 511 #endif
 512                 } else {
 513                   static const struct
 514                   {
 515                     char str[22];
 516                     uint8_t len;
 517                     uint8_t clear;
 518                     unsigned long int flag;
 519                   } options[] = {
 520 #define STRnLEN(str) str, sizeof (str) - 1
 521                     { STRnLEN ("inet6"), 0, RES_USE_INET6 },
 522                     { STRnLEN ("ip6-bytestring"), 0, RES_USEBSTRING },
 523                     { STRnLEN ("no-ip6-dotint"), 0, RES_NOIP6DOTINT },
 524                     { STRnLEN ("ip6-dotint"), 1, ~RES_NOIP6DOTINT },
 525                     { STRnLEN ("rotate"), 0, RES_ROTATE },
 526                     { STRnLEN ("no-check-names"), 0, RES_NOCHECKNAME },
 527                     { STRnLEN ("edns0"), 0, RES_USE_EDNS0 },
 528                     { STRnLEN ("single-request-reopen"), 0, RES_SNGLKUPREOP },
 529                     { STRnLEN ("single-request"), 0, RES_SNGLKUP },
 530                     { STRnLEN ("no_tld_query"), 0, RES_NOTLDQUERY },
 531                     { STRnLEN ("no-tld-query"), 0, RES_NOTLDQUERY },
 532                     { STRnLEN ("use-vc"), 0, RES_USEVC }
 533                   };
 534 #define noptions (sizeof (options) / sizeof (options[0]))
 535                   int i;
 536                   for (i = 0; i < noptions; ++i)
 537                     if (strncmp (cp, options[i].str, options[i].len) == 0)
 538                       {
 539                         if (options[i].clear)
 540                           statp->options &= options[i].flag;
 541                         else
 542                           statp->options |= options[i].flag;
 543                         break;
 544                       }
 545                   if (i == noptions) {
 546                     /* XXX - print a warning here? */
 547                   }
 548                 }
 549                 /* skip to next run of spaces */
 550                 while (*cp && *cp != ' ' && *cp != '\t')
 551                         cp++;
 552         }
 553 }
 554
 555 #ifdef RESOLVSORT
 556 /* XXX - should really support CIDR which means explicit masks always. */
 557 static u_int32_t
 558 net_mask(in)            /* XXX - should really use system's version of this */
 559         struct in_addr in;
 560 {
 561         u_int32_t i = ntohl(in.s_addr);
 562
 563         if (IN_CLASSA(i))
 564                 return (htonl(IN_CLASSA_NET));
 565         else if (IN_CLASSB(i))
 566                 return (htonl(IN_CLASSB_NET));
 567         return (htonl(IN_CLASSC_NET));
 568 }
 569 #endif
 570
 571 u_int
 572 res_randomid(void) {
 573         return 0xffff & __getpid();
 574 }
 575 #ifdef _LIBC
 576 libc_hidden_def (__res_randomid)
 577 #endif
 578
 579
 580 /*
 581  * This routine is for closing the socket if a virtual circuit is used and
 582  * the program wants to close it.  This provides support for endhostent()
 583  * which expects to close the socket.
 584  *
 585  * This routine is not expected to be user visible.
 586  */
 587 void
 588 __res_iclose(res_state statp, bool free_addr) {
 589         int ns;
 590
 591         if (statp->_vcsock >= 0) {
 592                 close_not_cancel_no_status(statp->_vcsock);
 593                 statp->_vcsock = -1;
 594                 statp->_flags &= ~(RES_F_VC | RES_F_CONN);
 595         }
 596         for (ns = 0; ns < statp->_u._ext.nscount; ns++)
 597                 if (statp->_u._ext.nsaddrs[ns]) {
 598                         if (statp->_u._ext.nssocks[ns] != -1) {
 599                                 close_not_cancel_no_status(statp->_u._ext.nssocks[ns]);
 600                                 statp->_u._ext.nssocks[ns] = -1;
 601                         }
 602                         if (free_addr) {
 603                                 free (statp->_u._ext.nsaddrs[ns]);
 604                                 statp->_u._ext.nsaddrs[ns] = NULL;
 605                         }
 606                 }
 607 }
 608 libc_hidden_def (__res_iclose)
 609
 610 void
 611 res_nclose(res_state statp)
 612 {
 613   __res_iclose (statp, true);
 614 }
 615 #ifdef _LIBC
 616 libc_hidden_def (__res_nclose)
 617 #endif
 618
 619 #ifdef _LIBC
 620 # ifdef _LIBC_REENTRANT
 621 /* This is called when a thread is exiting to free resources held in _res.  */
 622 static void __attribute__ ((section ("__libc_thread_freeres_fn")))
 623 res_thread_freeres (void)
 624 {
 625   if (_res.nscount == 0)
 626     /* Never called res_ninit.  */
 627     return;
 628
 629   __res_iclose (&_res, true);           /* Close any VC sockets.  */
 630
 631   /* Make sure we do a full re-initialization the next time.  */
 632   _res.options = 0;
 633 }
 634 text_set_element (__libc_thread_subfreeres, res_thread_freeres);
 635 text_set_element (__libc_subfreeres, res_thread_freeres);
 636 # endif
 637 #endif