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 <arpa/inet.h>
  81 #include <arpa/nameser.h>
  82 #include <net/if.h>
  83 #include <netinet/in.h>
  84 #include <sys/param.h>
  85 #include <sys/socket.h>
  86 #include <sys/time.h>
  87 #include <sys/types.h>
  88
  89 #include <not-cancel.h>
  90
  91 /* Options.  Should all be left alone. */
  92 #define RESOLVSORT
  93 #define RFC1535
  94 /* #undef DEBUG */
  95
  96 static void res_setoptions (res_state, const char *, const char *)
  97      internal_function;
  98
  99 #ifdef RESOLVSORT
 100 static const char sort_mask_chars[] = "/&";
 101 #define ISSORTMASK(ch) (strchr(sort_mask_chars, ch) != NULL)
 102 static u_int32_t net_mask (struct in_addr) __THROW;
 103 #endif
 104
 105 #if !defined(isascii)   /* XXX - could be a function */
 106 # define isascii(c) (!(c & 0200))
 107 #endif
 108
 109 #ifdef _LIBC
 110 unsigned long long int __res_initstamp attribute_hidden;
 111 #endif
 112
 113 /*
 114  * Resolver state default settings.
 115  */
 116
 117 /*
 118  * Set up default settings.  If the configuration file exist, the values
 119  * there will have precedence.  Otherwise, the server address is set to
 120  * INADDR_ANY and the default domain name comes from the gethostname().
 121  *
 122  * An interrim version of this code (BIND 4.9, pre-4.4BSD) used 127.0.0.1
 123  * rather than INADDR_ANY ("0.0.0.0") as the default name server address
 124  * since it was noted that INADDR_ANY actually meant ``the first interface
 125  * you "ifconfig"'d at boot time'' and if this was a SLIP or PPP interface,
 126  * it had to be "up" in order for you to reach your own name server.  It
 127  * was later decided that since the recommended practice is to always
 128  * install local static routes through 127.0.0.1 for all your network
 129  * interfaces, that we could solve this problem without a code change.
 130  *
 131  * The configuration file should always be used, since it is the only way
 132  * to specify a default domain.  If you are running a server on your local
 133  * machine, you should say "nameserver 0.0.0.0" or "nameserver 127.0.0.1"
 134  * in the configuration file.
 135  *
 136  * Return 0 if completes successfully, -1 on error
 137  */
 138 int
 139 res_ninit(res_state statp) {
 140         extern int __res_vinit(res_state, int);
 141
 142         return (__res_vinit(statp, 0));
 143 }
 144 #ifdef _LIBC
 145 libc_hidden_def (__res_ninit)
 146 #endif
 147
 148 /* This function has to be reachable by res_data.c but not publically. */
 149 int
 150 __res_vinit(res_state statp, int preinit) {
 151         register FILE *fp;
 152         register char *cp, **pp;
 153         register int n;
 154         char buf[BUFSIZ];
 155         int nserv = 0;    /* number of nameserver records read from file */
 156 #ifdef _LIBC
 157         int nservall = 0; /* number of NS records read, nserv IPv4 only */
 158 #endif
 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 #ifdef _LIBC
 169         statp->_u._ext.initstamp = __res_initstamp;
 170 #endif
 171
 172         if (!preinit) {
 173                 statp->retrans = RES_TIMEOUT;
 174                 statp->retry = RES_DFLRETRY;
 175                 statp->options = RES_DEFAULT;
 176                 statp->id = res_randomid();
 177         }
 178
 179 #ifdef USELOOPBACK
 180         statp->nsaddr.sin_addr = inet_makeaddr(IN_LOOPBACKNET, 1);
 181 #else
 182         statp->nsaddr.sin_addr.s_addr = INADDR_ANY;
 183 #endif
 184         statp->nsaddr.sin_family = AF_INET;
 185         statp->nsaddr.sin_port = htons(NAMESERVER_PORT);
 186         statp->nscount = 1;
 187         statp->ndots = 1;
 188         statp->pfcode = 0;
 189         statp->_vcsock = -1;
 190         statp->_flags = 0;
 191         statp->qhook = NULL;
 192         statp->rhook = NULL;
 193         statp->_u._ext.nsinit = 0;
 194         statp->_u._ext.nscount = 0;
 195 #ifdef _LIBC
 196         statp->_u._ext.nscount6 = 0;
 197         for (n = 0; n < MAXNS; n++) {
 198                 statp->_u._ext.nsaddrs[n] = NULL;
 199                 statp->_u._ext.nsmap[n] = MAXNS;
 200         }
 201 #endif
 202
 203         /* Allow user to override the local domain definition */
 204         if ((cp = getenv("LOCALDOMAIN")) != NULL) {
 205                 (void)strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
 206                 statp->defdname[sizeof(statp->defdname) - 1] = '\0';
 207                 haveenv++;
 208
 209                 /*
 210                  * Set search list to be blank-separated strings
 211                  * from rest of env value.  Permits users of LOCALDOMAIN
 212                  * to still have a search list, and anyone to set the
 213                  * one that they want to use as an individual (even more
 214                  * important now that the rfc1535 stuff restricts searches)
 215                  */
 216                 cp = statp->defdname;
 217                 pp = statp->dnsrch;
 218                 *pp++ = cp;
 219                 for (n = 0; *cp && pp < statp->dnsrch + MAXDNSRCH; cp++) {
 220                         if (*cp == '\n')        /* silly backwards compat */
 221                                 break;
 222                         else if (*cp == ' ' || *cp == '\t') {
 223                                 *cp = 0;
 224                                 n = 1;
 225                         } else if (n) {
 226                                 *pp++ = cp;
 227                                 n = 0;
 228                                 havesearch = 1;
 229                         }
 230                 }
 231                 /* null terminate last domain if there are excess */
 232                 while (*cp != '\0' && *cp != ' ' && *cp != '\t' && *cp != '\n')
 233                         cp++;
 234                 *cp = '\0';
 235                 *pp++ = 0;
 236         }
 237
 238 #define MATCH(line, name) \
 239         (!strncmp(line, name, sizeof(name) - 1) && \
 240         (line[sizeof(name) - 1] == ' ' || \
 241          line[sizeof(name) - 1] == '\t'))
 242
 243         if ((fp = fopen(_PATH_RESCONF, "rc")) != NULL) {
 244             /* No threads use this stream.  */
 245             __fsetlocking (fp, FSETLOCKING_BYCALLER);
 246             /* read the config file */
 247             while (fgets_unlocked(buf, sizeof(buf), fp) != NULL) {
 248                 /* skip comments */
 249                 if (*buf == ';' || *buf == '#')
 250                         continue;
 251                 /* read default domain name */
 252                 if (MATCH(buf, "domain")) {
 253                     if (haveenv)        /* skip if have from environ */
 254                             continue;
 255                     cp = buf + sizeof("domain") - 1;
 256                     while (*cp == ' ' || *cp == '\t')
 257                             cp++;
 258                     if ((*cp == '\0') || (*cp == '\n'))
 259                             continue;
 260                     strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
 261                     statp->defdname[sizeof(statp->defdname) - 1] = '\0';
 262                     if ((cp = strpbrk(statp->defdname, " \t\n")) != NULL)
 263                             *cp = '\0';
 264                     havesearch = 0;
 265                     continue;
 266                 }
 267                 /* set search list */
 268                 if (MATCH(buf, "search")) {
 269                     if (haveenv)        /* skip if have from environ */
 270                             continue;
 271                     cp = buf + sizeof("search") - 1;
 272                     while (*cp == ' ' || *cp == '\t')
 273                             cp++;
 274                     if ((*cp == '\0') || (*cp == '\n'))
 275                             continue;
 276                     strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
 277                     statp->defdname[sizeof(statp->defdname) - 1] = '\0';
 278                     if ((cp = strchr(statp->defdname, '\n')) != NULL)
 279                             *cp = '\0';
 280                     /*
 281                      * Set search list to be blank-separated strings
 282                      * on rest of line.
 283                      */
 284                     cp = statp->defdname;
 285                     pp = statp->dnsrch;
 286                     *pp++ = cp;
 287                     for (n = 0; *cp && pp < statp->dnsrch + MAXDNSRCH; cp++) {
 288                             if (*cp == ' ' || *cp == '\t') {
 289                                     *cp = 0;
 290                                     n = 1;
 291                             } else if (n) {
 292                                     *pp++ = cp;
 293                                     n = 0;
 294                             }
 295                     }
 296                     /* null terminate last domain if there are excess */
 297                     while (*cp != '\0' && *cp != ' ' && *cp != '\t')
 298                             cp++;
 299                     *cp = '\0';
 300                     *pp++ = 0;
 301                     havesearch = 1;
 302                     continue;
 303                 }
 304                 /* read nameservers to query */
 305 #ifdef _LIBC
 306                 if (MATCH(buf, "nameserver") && nservall < MAXNS) {
 307 #else
 308                 if (MATCH(buf, "nameserver") && nserv < MAXNS) {
 309 #endif
 310                     struct in_addr a;
 311
 312                     cp = buf + sizeof("nameserver") - 1;
 313                     while (*cp == ' ' || *cp == '\t')
 314                         cp++;
 315                     if ((*cp != '\0') && (*cp != '\n')
 316                         && __inet_aton(cp, &a)) {
 317                         statp->nsaddr_list[nserv].sin_addr = a;
 318                         statp->nsaddr_list[nserv].sin_family = AF_INET;
 319                         statp->nsaddr_list[nserv].sin_port =
 320                                 htons(NAMESERVER_PORT);
 321                         nserv++;
 322 #ifdef _LIBC
 323                         nservall++;
 324                     } else {
 325                         struct in6_addr a6;
 326                         char *el;
 327
 328                         if ((el = strchr(cp, '\n')) != NULL)
 329                             *el = '\0';
 330                         if ((el = strchr(cp, SCOPE_DELIMITER)) != NULL)
 331                             *el = '\0';
 332                         if ((*cp != '\0') &&
 333                             (inet_pton(AF_INET6, cp, &a6) > 0)) {
 334                             struct sockaddr_in6 *sa6;
 335
 336                             sa6 = malloc(sizeof(*sa6));
 337                             if (sa6 != NULL) {
 338                                 sa6->sin6_family = AF_INET6;
 339                                 sa6->sin6_port = htons(NAMESERVER_PORT);
 340                                 sa6->sin6_flowinfo = 0;
 341                                 sa6->sin6_addr = a6;
 342
 343                                 if (__builtin_expect (el == NULL, 1))
 344                                     sa6->sin6_scope_id = 0;
 345                                 else {
 346                                     int try_numericscope = 1;
 347                                     if (IN6_IS_ADDR_LINKLOCAL (&a6)
 348                                         || IN6_IS_ADDR_MC_LINKLOCAL (&a6)) {
 349                                         sa6->sin6_scope_id
 350                                           = if_nametoindex (el + 1);
 351                                         if (sa6->sin6_scope_id != 0)
 352                                             try_numericscope = 0;
 353                                     }
 354
 355                                     if (try_numericscope) {
 356                                         char *end;
 357                                         sa6->sin6_scope_id
 358                                           = (uint32_t) strtoul (el + 1, &end,
 359                                                                 10);
 360                                         if (*end != '\0')
 361                                             sa6->sin6_scope_id = 0;
 362                                     }
 363                                 }
 364
 365                                 statp->_u._ext.nsaddrs[nservall] = sa6;
 366                                 statp->_u._ext.nssocks[nservall] = -1;
 367                                 statp->_u._ext.nsmap[nservall] = MAXNS + 1;
 368                                 nservall++;
 369                             }
 370                         }
 371 #endif
 372                     }
 373                     continue;
 374                 }
 375 #ifdef RESOLVSORT
 376                 if (MATCH(buf, "sortlist")) {
 377                     struct in_addr a;
 378
 379                     cp = buf + sizeof("sortlist") - 1;
 380                     while (nsort < MAXRESOLVSORT) {
 381                         while (*cp == ' ' || *cp == '\t')
 382                             cp++;
 383                         if (*cp == '\0' || *cp == '\n' || *cp == ';')
 384                             break;
 385                         net = cp;
 386                         while (*cp && !ISSORTMASK(*cp) && *cp != ';' &&
 387                                isascii(*cp) && !isspace(*cp))
 388                                 cp++;
 389                         n = *cp;
 390                         *cp = 0;
 391                         if (__inet_aton(net, &a)) {
 392                             statp->sort_list[nsort].addr = a;
 393                             if (ISSORTMASK(n)) {
 394                                 *cp++ = n;
 395                                 net = cp;
 396                                 while (*cp && *cp != ';' &&
 397                                         isascii(*cp) && !isspace(*cp))
 398                                     cp++;
 399                                 n = *cp;
 400                                 *cp = 0;
 401                                 if (__inet_aton(net, &a)) {
 402                                     statp->sort_list[nsort].mask = a.s_addr;
 403                                 } else {
 404                                     statp->sort_list[nsort].mask =
 405                                         net_mask(statp->sort_list[nsort].addr);
 406                                 }
 407                             } else {
 408                                 statp->sort_list[nsort].mask =
 409                                     net_mask(statp->sort_list[nsort].addr);
 410                             }
 411                             nsort++;
 412                         }
 413                         *cp = n;
 414                     }
 415                     continue;
 416                 }
 417 #endif
 418                 if (MATCH(buf, "options")) {
 419                     res_setoptions(statp, buf + sizeof("options") - 1, "conf");
 420                     continue;
 421                 }
 422             }
 423             if (nserv > 1)
 424                 statp->nscount = nserv;
 425 #ifdef _LIBC
 426             if (nservall - nserv > 0) {
 427                 statp->_u._ext.nscount6 = nservall - nserv;
 428                 /* We try IPv6 servers again.  */
 429                 statp->ipv6_unavail = false;
 430             }
 431 #endif
 432 #ifdef RESOLVSORT
 433             statp->nsort = nsort;
 434 #endif
 435             (void) fclose(fp);
 436         }
 437         if (statp->defdname[0] == 0 &&
 438             __gethostname(buf, sizeof(statp->defdname) - 1) == 0 &&
 439             (cp = strchr(buf, '.')) != NULL)
 440                 strcpy(statp->defdname, cp + 1);
 441
 442         /* find components of local domain that might be searched */
 443         if (havesearch == 0) {
 444                 pp = statp->dnsrch;
 445                 *pp++ = statp->defdname;
 446                 *pp = NULL;
 447
 448 #ifndef RFC1535
 449                 dots = 0;
 450                 for (cp = statp->defdname; *cp; cp++)
 451                         dots += (*cp == '.');
 452
 453                 cp = statp->defdname;
 454                 while (pp < statp->dnsrch + MAXDFLSRCH) {
 455                         if (dots < LOCALDOMAINPARTS)
 456                                 break;
 457                         cp = __rawmemchr(cp, '.') + 1;    /* we know there is one */
 458                         *pp++ = cp;
 459                         dots--;
 460                 }
 461                 *pp = NULL;
 462 #ifdef DEBUG
 463                 if (statp->options & RES_DEBUG) {
 464                         printf(";; res_init()... default dnsrch list:\n");
 465                         for (pp = statp->dnsrch; *pp; pp++)
 466                                 printf(";;\t%s\n", *pp);
 467                         printf(";;\t..END..\n");
 468                 }
 469 #endif
 470 #endif /* !RFC1535 */
 471         }
 472
 473         if ((cp = getenv("RES_OPTIONS")) != NULL)
 474                 res_setoptions(statp, cp, "env");
 475         statp->options |= RES_INIT;
 476         return (0);
 477 }
 478
 479 static void
 480 internal_function
 481 res_setoptions(res_state statp, const char *options, const char *source) {
 482         const char *cp = options;
 483         int i;
 484
 485 #ifdef DEBUG
 486         if (statp->options & RES_DEBUG)
 487                 printf(";; res_setoptions(\"%s\", \"%s\")...\n",
 488                        options, source);
 489 #endif
 490         while (*cp) {
 491                 /* skip leading and inner runs of spaces */
 492                 while (*cp == ' ' || *cp == '\t')
 493                         cp++;
 494                 /* search for and process individual options */
 495                 if (!strncmp(cp, "ndots:", sizeof("ndots:") - 1)) {
 496                         i = atoi(cp + sizeof("ndots:") - 1);
 497                         if (i <= RES_MAXNDOTS)
 498                                 statp->ndots = i;
 499                         else
 500                                 statp->ndots = RES_MAXNDOTS;
 501 #ifdef DEBUG
 502                         if (statp->options & RES_DEBUG)
 503                                 printf(";;\tndots=%d\n", statp->ndots);
 504 #endif
 505                 } else if (!strncmp(cp, "timeout:", sizeof("timeout:") - 1)) {
 506                         i = atoi(cp + sizeof("timeout:") - 1);
 507                         if (i <= RES_MAXRETRANS)
 508                                 statp->retrans = i;
 509                         else
 510                                 statp->retrans = RES_MAXRETRANS;
 511                 } else if (!strncmp(cp, "attempts:", sizeof("attempts:") - 1)){
 512                         i = atoi(cp + sizeof("attempts:") - 1);
 513                         if (i <= RES_MAXRETRY)
 514                                 statp->retry = i;
 515                         else
 516                                 statp->retry = RES_MAXRETRY;
 517                 } else if (!strncmp(cp, "debug", sizeof("debug") - 1)) {
 518 #ifdef DEBUG
 519                         if (!(statp->options & RES_DEBUG)) {
 520                                 printf(";; res_setoptions(\"%s\", \"%s\")..\n",
 521                                        options, source);
 522                                 statp->options |= RES_DEBUG;
 523                         }
 524                         printf(";;\tdebug\n");
 525 #endif
 526                 } else if (!strncmp(cp, "inet6", sizeof("inet6") - 1)) {
 527                         statp->options |= RES_USE_INET6;
 528                 } else if (!strncmp(cp, "ip6-bytestring",
 529                                     sizeof("ip6-bytestring") - 1)) {
 530                         statp->options |= RES_USEBSTRING;
 531                 } else if (!strncmp(cp, "no-ip6-dotint",
 532                                     sizeof("no-ip6-dotint") - 1)) {
 533                         statp->options |= RES_NOIP6DOTINT;
 534                 } else if (!strncmp(cp, "ip6-dotint",
 535                                     sizeof("ip6-dotint") - 1)) {
 536                         statp->options &= ~RES_NOIP6DOTINT;
 537                 } else if (!strncmp(cp, "rotate", sizeof("rotate") - 1)) {
 538                         statp->options |= RES_ROTATE;
 539                 } else if (!strncmp(cp, "no-check-names",
 540                                     sizeof("no-check-names") - 1)) {
 541                         statp->options |= RES_NOCHECKNAME;
 542                 } else if (!strncmp(cp, "edns0", sizeof("edns0") - 1)) {
 543                         statp->options |= RES_USE_EDNS0;
 544                 } else {
 545                         /* XXX - print a warning here? */
 546                 }
 547                 /* skip to next run of spaces */
 548                 while (*cp && *cp != ' ' && *cp != '\t')
 549                         cp++;
 550         }
 551 }
 552
 553 #ifdef RESOLVSORT
 554 /* XXX - should really support CIDR which means explicit masks always. */
 555 static u_int32_t
 556 net_mask(in)            /* XXX - should really use system's version of this */
 557         struct in_addr in;
 558 {
 559         register u_int32_t i = ntohl(in.s_addr);
 560
 561         if (IN_CLASSA(i))
 562                 return (htonl(IN_CLASSA_NET));
 563         else if (IN_CLASSB(i))
 564                 return (htonl(IN_CLASSB_NET));
 565         return (htonl(IN_CLASSC_NET));
 566 }
 567 #endif
 568
 569 u_int
 570 res_randomid(void) {
 571         return 0xffff & __getpid();
 572 }
 573 #ifdef _LIBC
 574 libc_hidden_def (__res_randomid)
 575 #endif
 576
 577
 578 /*
 579  * This routine is for closing the socket if a virtual circuit is used and
 580  * the program wants to close it.  This provides support for endhostent()
 581  * which expects to close the socket.
 582  *
 583  * This routine is not expected to be user visible.
 584  */
 585 void
 586 __res_iclose(res_state statp, bool free_addr) {
 587         int ns;
 588
 589         if (statp->_vcsock >= 0) {
 590                 close_not_cancel_no_status(statp->_vcsock);
 591                 statp->_vcsock = -1;
 592                 statp->_flags &= ~(RES_F_VC | RES_F_CONN);
 593         }
 594 #ifdef _LIBC
 595         for (ns = 0; ns < MAXNS; ns++)
 596 #else
 597         for (ns = 0; ns < statp->_u._ext.nscount; ns++)
 598 #endif
 599                 if (statp->_u._ext.nsaddrs[ns]) {
 600                         if (statp->_u._ext.nssocks[ns] != -1) {
 601                                 close_not_cancel_no_status(statp->_u._ext.nssocks[ns]);
 602                                 statp->_u._ext.nssocks[ns] = -1;
 603                         }
 604                         if (free_addr) {
 605                                 free (statp->_u._ext.nsaddrs[ns]);
 606                                 statp->_u._ext.nsaddrs[ns] = NULL;
 607                         }
 608                 }
 609         statp->_u._ext.nsinit = 0;
 610 }
 611 libc_hidden_def (__res_iclose)
 612
 613 void
 614 res_nclose(res_state statp)
 615 {
 616   __res_iclose (statp, true);
 617 }
 618 #ifdef _LIBC
 619 libc_hidden_def (__res_nclose)
 620 #endif
 621
 622 #ifdef _LIBC
 623 # ifdef _LIBC_REENTRANT
 624 /* This is called when a thread is exiting to free resources held in _res.  */
 625 static void __attribute__ ((section ("__libc_thread_freeres_fn")))
 626 res_thread_freeres (void)
 627 {
 628   if (_res.nscount == 0)
 629     /* Never called res_ninit.  */
 630     return;
 631
 632   __res_iclose (&_res, true);           /* Close any VC sockets.  */
 633
 634   /* Make sure we do a full re-initialization the next time.  */
 635   _res.options = 0;
 636 }
 637 text_set_element (__libc_thread_subfreeres, res_thread_freeres);
 638 text_set_element (__libc_subfreeres, res_thread_freeres);
 639 # endif
 640 #endif