dist/dhcp/minires/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  * 3. 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) 2004 by Internet Systems Consortium, Inc. ("ISC")
  52  * Portions Copyright (c) 1995-2003 by Internet Software Consortium
  53  *
  54  * Permission to use, copy, modify, and distribute this software for any
  55  * purpose with or without fee is hereby granted, provided that the above
  56  * copyright notice and this permission notice appear in all copies.
  57  *
  58  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
  59  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  60  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
  61  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  62  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  63  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  64  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  65  *
  66  *   Internet Systems Consortium, Inc.
  67  *   950 Charter Street
  68  *   Redwood City, CA 94063
  69  *   <info@isc.org>
  70  *   http://www.isc.org/
  71  */
  72
  73 #if defined(LIBC_SCCS) && !defined(lint)
  74 static const char sccsid[] = "@(#)res_init.c    8.1 (Berkeley) 6/7/93";
  75 static const char rcsid[] = "$Id: res_init.c,v 1.5 2007/05/27 16:27:57 tls Exp $";
  76 #endif /* LIBC_SCCS and not lint */
  77
  78 #include <sys/types.h>
  79 #include <sys/param.h>
  80 #include <sys/socket.h>
  81 #include <sys/time.h>
  82
  83 #include <netinet/in.h>
  84 #include <arpa/inet.h>
  85
  86 #include <ctype.h>
  87 #include <stdio.h>
  88 #include <stdlib.h>
  89 #include <string.h>
  90 #include <unistd.h>
  91
  92 #include "minires/minires.h"
  93 #include "omapip/trace_mr.h"
  94 #include "arpa/nameser.h"
  95
  96 /* Options.  Should all be left alone. */
  97 #define RESOLVSORT
  98 #define RFC1535
  99 #define DEBUG
 100
 101 static void res_setoptions (res_state, const char *, const char *);
 102
 103 #ifdef RESOLVSORT
 104 static const char sort_mask[] = "/&";
 105 #define ISSORTMASK(ch) (strchr(sort_mask, ch) != NULL)
 106 static u_int32_t net_mask (struct in_addr);
 107 #endif
 108
 109 #if !defined(isascii)   /* XXX - could be a function */
 110 # define isascii(c) (!(c & 0200))
 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 extern int minires_vinit(res_state, int);
 139
 140 #if defined (TRACING)
 141 u_int trace_mr_res_randomid(u_int);
 142 #endif
 143
 144 int
 145 res_ninit(res_state statp) {
 146
 147         return (minires_vinit(statp, 0));
 148 }
 149
 150 /* This function has to be reachable by res_data.c but not publically. */
 151 int
 152 minires_vinit(res_state statp, int preinit) {
 153         register FILE *fp;
 154         register char *cp, **pp;
 155         register int n;
 156         char buf[BUFSIZ];
 157         int nserv = 0;    /* number of nameserver records read from file */
 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
 168         if (!preinit) {
 169                 statp->retrans = RES_TIMEOUT;
 170                 statp->retry = RES_DFLRETRY;
 171                 statp->options = RES_DEFAULT;
 172                 statp->id = res_randomid();
 173 #if defined (TRACING)
 174                 statp->id = trace_mr_res_randomid (statp -> id);
 175 #endif
 176         }
 177
 178 #ifdef USELOOPBACK
 179         statp->nsaddr.sin_addr = inet_makeaddr(IN_LOOPBACKNET, 1);
 180 #else
 181         statp->nsaddr.sin_addr.s_addr = INADDR_ANY;
 182 #endif
 183         statp->nsaddr.sin_family = AF_INET;
 184         statp->nsaddr.sin_port = htons(NAMESERVER_PORT);
 185         statp->nscount = 1;
 186         statp->ndots = 1;
 187         statp->pfcode = 0;
 188         statp->_sock = -1;
 189         statp->_flags = 0;
 190         statp->qhook = NULL;
 191         statp->rhook = NULL;
 192
 193         /* Allow user to override the local domain definition */
 194         if ((cp = getenv("LOCALDOMAIN")) != NULL) {
 195                 (void)strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
 196                 statp->defdname[sizeof(statp->defdname) - 1] = '\0';
 197                 haveenv++;
 198
 199                 /*
 200                  * Set search list to be blank-separated strings
 201                  * from rest of env value.  Permits users of LOCALDOMAIN
 202                  * to still have a search list, and anyone to set the
 203                  * one that they want to use as an individual (even more
 204                  * important now that the rfc1535 stuff restricts searches)
 205                  */
 206                 cp = statp->defdname;
 207                 pp = statp->dnsrch;
 208                 *pp++ = cp;
 209                 for (n = 0; *cp && pp < statp->dnsrch + MAXDNSRCH; cp++) {
 210                         if (*cp == '\n')        /* silly backwards compat */
 211                                 break;
 212                         else if (*cp == ' ' || *cp == '\t') {
 213                                 *cp = 0;
 214                                 n = 1;
 215                         } else if (n) {
 216                                 *pp++ = cp;
 217                                 n = 0;
 218                                 havesearch = 1;
 219                         }
 220                 }
 221                 /* null terminate last domain if there are excess */
 222                 while (*cp != '\0' && *cp != ' ' && *cp != '\t' && *cp != '\n')
 223                         cp++;
 224                 *cp = '\0';
 225                 *pp++ = 0;
 226         }
 227
 228 #define MATCH(line, name) \
 229         (!strncmp(line, name, sizeof(name) - 1) && \
 230         (line[sizeof(name) - 1] == ' ' || \
 231          line[sizeof(name) - 1] == '\t'))
 232
 233         if ((fp = fopen(_PATH_RESCONF, "r")) != NULL) {
 234             /* read the config file */
 235             while (fgets(buf, sizeof(buf), fp) != NULL) {
 236                 /* skip comments */
 237                 if (*buf == ';' || *buf == '#')
 238                         continue;
 239                 /* read default domain name */
 240                 if (MATCH(buf, "domain")) {
 241                     if (haveenv)        /* skip if have from environ */
 242                             continue;
 243                     cp = buf + sizeof("domain") - 1;
 244                     while (*cp == ' ' || *cp == '\t')
 245                             cp++;
 246                     if ((*cp == '\0') || (*cp == '\n'))
 247                             continue;
 248                     strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
 249                     statp->defdname[sizeof(statp->defdname) - 1] = '\0';
 250                     if ((cp = strpbrk(statp->defdname, " \t\n")) != NULL)
 251                             *cp = '\0';
 252                     havesearch = 0;
 253                     continue;
 254                 }
 255                 /* set search list */
 256                 if (MATCH(buf, "search")) {
 257                     if (haveenv)        /* skip if have from environ */
 258                             continue;
 259                     cp = buf + sizeof("search") - 1;
 260                     while (*cp == ' ' || *cp == '\t')
 261                             cp++;
 262                     if ((*cp == '\0') || (*cp == '\n'))
 263                             continue;
 264                     strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
 265                     statp->defdname[sizeof(statp->defdname) - 1] = '\0';
 266                     if ((cp = strchr(statp->defdname, '\n')) != NULL)
 267                             *cp = '\0';
 268                     /*
 269                      * Set search list to be blank-separated strings
 270                      * on rest of line.
 271                      */
 272                     cp = statp->defdname;
 273                     pp = statp->dnsrch;
 274                     *pp++ = cp;
 275                     for (n = 0; *cp && pp < statp->dnsrch + MAXDNSRCH; cp++) {
 276                             if (*cp == ' ' || *cp == '\t') {
 277                                     *cp = 0;
 278                                     n = 1;
 279                             } else if (n) {
 280                                     *pp++ = cp;
 281                                     n = 0;
 282                             }
 283                     }
 284                     /* null terminate last domain if there are excess */
 285                     while (*cp != '\0' && *cp != ' ' && *cp != '\t')
 286                             cp++;
 287                     *cp = '\0';
 288                     *pp++ = 0;
 289                     havesearch = 1;
 290                     continue;
 291                 }
 292                 /* read nameservers to query */
 293                 if (MATCH(buf, "nameserver") && nserv < MAXNS) {
 294                     struct in_addr a;
 295
 296                     cp = buf + sizeof("nameserver") - 1;
 297                     while (*cp == ' ' || *cp == '\t')
 298                         cp++;
 299                     if ((*cp != '\0') && (*cp != '\n') && inet_aton(cp, &a)) {
 300                         statp->nsaddr_list[nserv].sin_addr = a;
 301                         statp->nsaddr_list[nserv].sin_family = AF_INET;
 302                         statp->nsaddr_list[nserv].sin_port =
 303                                 htons(NAMESERVER_PORT);
 304                         nserv++;
 305                     }
 306                     continue;
 307                 }
 308 #ifdef RESOLVSORT
 309                 if (MATCH(buf, "sortlist")) {
 310                     struct in_addr a;
 311
 312                     cp = buf + sizeof("sortlist") - 1;
 313                     while (nsort < MAXRESOLVSORT) {
 314                         while (*cp == ' ' || *cp == '\t')
 315                             cp++;
 316                         if (*cp == '\0' || *cp == '\n' || *cp == ';')
 317                             break;
 318                         net = cp;
 319                         while (*cp && !ISSORTMASK(*cp) && *cp != ';' &&
 320                                !isspace((unsigned char)*cp))
 321                                 cp++;
 322                         n = *cp;
 323                         *cp = 0;
 324                         if (inet_aton(net, &a)) {
 325                             statp->sort_list[nsort].addr = a;
 326                             if (ISSORTMASK(n)) {
 327                                 *cp++ = n;
 328                                 net = cp;
 329                                 while (*cp && *cp != ';' &&
 330                                         !isspace((unsigned char)*cp))
 331                                     cp++;
 332                                 n = *cp;
 333                                 *cp = 0;
 334                                 if (inet_aton(net, &a)) {
 335                                     statp->sort_list[nsort].mask = a.s_addr;
 336                                 } else {
 337                                     statp->sort_list[nsort].mask =
 338                                         net_mask(statp->sort_list[nsort].addr);
 339                                 }
 340                             } else {
 341                                 statp->sort_list[nsort].mask =
 342                                     net_mask(statp->sort_list[nsort].addr);
 343                             }
 344                             nsort++;
 345                         }
 346                         *cp = n;
 347                     }
 348                     continue;
 349                 }
 350 #endif
 351                 if (MATCH(buf, "options")) {
 352                     res_setoptions(statp, buf + sizeof("options") - 1, "conf");
 353                     continue;
 354                 }
 355             }
 356             if (nserv > 1)
 357                 statp->nscount = nserv;
 358 #ifdef RESOLVSORT
 359             statp->nsort = nsort;
 360 #endif
 361             (void) fclose(fp);
 362         }
 363         if (statp->defdname[0] == 0 &&
 364             gethostname(buf, sizeof(statp->defdname) - 1) == 0 &&
 365             (cp = strchr(buf, '.')) != NULL)
 366                 strcpy(statp->defdname, cp + 1);
 367
 368         /* find components of local domain that might be searched */
 369         if (havesearch == 0) {
 370                 pp = statp->dnsrch;
 371                 *pp++ = statp->defdname;
 372                 *pp = NULL;
 373
 374 #ifndef RFC1535
 375                 dots = 0;
 376                 for (cp = statp->defdname; *cp; cp++)
 377                         dots += (*cp == '.');
 378
 379                 cp = statp->defdname;
 380                 while (pp < statp->dnsrch + MAXDFLSRCH) {
 381                         if (dots < LOCALDOMAINPARTS)
 382                                 break;
 383                         cp = strchr(cp, '.') + 1;    /* we know there is one */
 384                         *pp++ = cp;
 385                         dots--;
 386                 }
 387                 *pp = NULL;
 388 #ifdef DEBUG
 389                 if (statp->options & RES_DEBUG) {
 390                         printf(";; res_init()... default dnsrch list:\n");
 391                         for (pp = statp->dnsrch; *pp; pp++)
 392                                 printf(";;\t%s\n", *pp);
 393                         printf(";;\t..END..\n");
 394                 }
 395 #endif
 396 #endif /* !RFC1535 */
 397         }
 398
 399         if ((cp = getenv("RES_OPTIONS")) != NULL)
 400                 res_setoptions(statp, cp, "env");
 401         statp->options |= RES_INIT;
 402         return (0);
 403 }
 404
 405 static void
 406 res_setoptions(res_state statp, const char *options, const char *source) {
 407         const char *cp = options;
 408         int i;
 409
 410 #ifdef DEBUG
 411         if (statp->options & RES_DEBUG)
 412                 printf(";; res_setoptions(\"%s\", \"%s\")...\n",
 413                        options, source);
 414 #endif
 415         while (*cp) {
 416                 /* skip leading and inner runs of spaces */
 417                 while (*cp == ' ' || *cp == '\t')
 418                         cp++;
 419                 /* search for and process individual options */
 420                 if (!strncmp(cp, "ndots:", sizeof("ndots:") - 1)) {
 421                         i = atoi(cp + sizeof("ndots:") - 1);
 422                         if (i <= RES_MAXNDOTS)
 423                                 statp->ndots = i;
 424                         else
 425                                 statp->ndots = RES_MAXNDOTS;
 426 #ifdef DEBUG
 427                         if (statp->options & RES_DEBUG)
 428                                 printf(";;\tndots=%d\n", statp->ndots);
 429 #endif
 430                 } else if (!strncmp(cp, "timeout:", sizeof("timeout:") - 1)) {
 431                         i = atoi(cp + sizeof("timeout:") - 1);
 432                         if (i <= RES_MAXRETRANS)
 433                                 statp->retrans = i;
 434                         else
 435                                 statp->retrans = RES_MAXRETRANS;
 436                 } else if (!strncmp(cp, "attempts:", sizeof("attempts:") - 1)){
 437                         i = atoi(cp + sizeof("attempts:") - 1);
 438                         if (i <= RES_MAXRETRY)
 439                                 statp->retry = i;
 440                         else
 441                                 statp->retry = RES_MAXRETRY;
 442                 } else if (!strncmp(cp, "debug", sizeof("debug") - 1)) {
 443 #ifdef DEBUG
 444                         if (!(statp->options & RES_DEBUG)) {
 445                                 printf(";; res_setoptions(\"%s\", \"%s\")..\n",
 446                                        options, source);
 447                                 statp->options |= RES_DEBUG;
 448                         }
 449                         printf(";;\tdebug\n");
 450 #endif
 451                 } else if (!strncmp(cp, "inet6", sizeof("inet6") - 1)) {
 452                         statp->options |= RES_USE_INET6;
 453                 } else if (!strncmp(cp, "rotate", sizeof("rotate") - 1)) {
 454                         statp->options |= RES_ROTATE;
 455                 } else if (!strncmp(cp, "no-check-names",
 456                                     sizeof("no-check-names") - 1)) {
 457                         statp->options |= RES_NOCHECKNAME;
 458                 } else {
 459                         /* XXX - print a warning here? */
 460                 }
 461                 /* skip to next run of spaces */
 462                 while (*cp && *cp != ' ' && *cp != '\t')
 463                         cp++;
 464         }
 465 }
 466
 467 #ifdef RESOLVSORT
 468 /* XXX - should really support CIDR which means explicit masks always. */
 469 static u_int32_t
 470 net_mask(in)            /* XXX - should really use system's version of this */
 471         struct in_addr in;
 472 {
 473         register u_int32_t i = ntohl(in.s_addr);
 474
 475         if (IN_CLASSA(i))
 476                 return (htonl(IN_CLASSA_NET));
 477         else if (IN_CLASSB(i))
 478                 return (htonl(IN_CLASSB_NET));
 479         return (htonl(IN_CLASSC_NET));
 480 }
 481 #endif
 482
 483 u_int
 484 res_randomid(void) {
 485         struct timeval now;
 486
 487         gettimeofday(&now, NULL);
 488         return (0xffff & (now.tv_sec ^ now.tv_usec ^ getpid()));
 489 }