1/* Resolver state initialization and resolv.conf parsing.
2 Copyright (C) 1995-2021 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19/*
20 * Copyright (c) 1985, 1989, 1993
21 * The Regents of the University of California. All rights reserved.
22 *
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
25 * are met:
26 * 1. Redistributions of source code must retain the above copyright
27 * notice, this list of conditions and the following disclaimer.
28 * 2. Redistributions in binary form must reproduce the above copyright
29 * notice, this list of conditions and the following disclaimer in the
30 * documentation and/or other materials provided with the distribution.
31 * 4. Neither the name of the University nor the names of its contributors
32 * may be used to endorse or promote products derived from this software
33 * without specific prior written permission.
34 *
35 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
36 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
37 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
38 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
39 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
40 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
41 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
42 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
43 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
44 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
45 * SUCH DAMAGE.
46 */
47
48/*
49 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
50 *
51 * Permission to use, copy, modify, and distribute this software for any
52 * purpose with or without fee is hereby granted, provided that the above
53 * copyright notice and this permission notice appear in all copies, and that
54 * the name of Digital Equipment Corporation not be used in advertising or
55 * publicity pertaining to distribution of the document or software without
56 * specific, written prior permission.
57 *
58 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
59 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
60 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
61 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
62 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
63 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
64 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
65 * SOFTWARE.
66 */
67
68/*
69 * Portions Copyright (c) 1996-1999 by Internet Software Consortium.
70 *
71 * Permission to use, copy, modify, and distribute this software for any
72 * purpose with or without fee is hereby granted, provided that the above
73 * copyright notice and this permission notice appear in all copies.
74 *
75 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
76 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
77 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
78 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
79 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
80 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
81 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
82 * SOFTWARE.
83 */
84
85#include <ctype.h>
86#include <netdb.h>
87#include <resolv/resolv-internal.h>
88#include <res_hconf.h>
89#include <stdio.h>
90#include <stdio_ext.h>
91#include <stdlib.h>
92#include <string.h>
93#include <unistd.h>
94#include <stdint.h>
95#include <arpa/inet.h>
96#include <arpa/nameser.h>
97#include <net/if.h>
98#include <netinet/in.h>
99#include <sys/param.h>
100#include <sys/socket.h>
101#include <sys/time.h>
102#include <sys/types.h>
103#include <inet/net-internal.h>
104#include <errno.h>
105#include <resolv_conf.h>
106#include <file_change_detection.h>
107
108static uint32_t net_mask (struct in_addr);
109
110int
111res_ninit (res_state statp)
112{
113 return __res_vinit (statp, 0);
114}
115libc_hidden_def (__res_ninit)
116
117/* Return true if CH separates the netmask in the "sortlist"
118 directive. */
119static inline bool
120is_sort_mask (char ch)
121{
122 return ch == '/' || ch == '&';
123}
124
125/* Array of name server addresses. */
126#define DYNARRAY_STRUCT nameserver_list
127#define DYNARRAY_ELEMENT const struct sockaddr *
128#define DYNARRAY_ELEMENT_FREE(e) free ((struct sockaddr *) *(e))
129#define DYNARRAY_INITIAL_SIZE 3
130#define DYNARRAY_PREFIX nameserver_list_
131#include <malloc/dynarray-skeleton.c>
132
133/* Array of strings for the search array. The backing store is
134 managed separately. */
135#define DYNARRAY_STRUCT search_list
136#define DYNARRAY_ELEMENT const char *
137#define DYNARRAY_INITIAL_SIZE 6
138#define DYNARRAY_PREFIX search_list_
139#include <malloc/dynarray-skeleton.c>
140
141/* Array of name server addresses. */
142#define DYNARRAY_STRUCT sort_list
143#define DYNARRAY_ELEMENT struct resolv_sortlist_entry
144#define DYNARRAY_INITIAL_SIZE 0
145#define DYNARRAY_PREFIX sort_list_
146#include <malloc/dynarray-skeleton.c>
147
148/* resolv.conf parser state and results. */
149struct resolv_conf_parser
150{
151 char *buffer; /* Temporary buffer for reading lines. */
152
153 struct nameserver_list nameserver_list; /* Nameserver addresses. */
154
155 char *search_list_store; /* Backing storage for search list entries. */
156 struct search_list search_list; /* Points into search_list_store. */
157
158 struct sort_list sort_list; /* Address preference sorting list. */
159
160 /* Configuration template. The non-array elements are filled in
161 directly. The array elements are updated prior to the call to
162 __resolv_conf_attach. */
163 struct resolv_conf template;
164};
165
166/* Return true if *PREINIT contains actual preinitialization. */
167static bool
168has_preinit_values (const struct __res_state *preinit)
169{
170 return (preinit->retrans != 0 && preinit->retrans != RES_TIMEOUT)
171 || (preinit->retry != 0 && preinit->retry != RES_DFLRETRY)
172 || (preinit->options != 0
173 && (preinit->options & ~RES_INIT) != RES_DEFAULT);
174}
175
176static void
177resolv_conf_parser_init (struct resolv_conf_parser *parser,
178 const struct __res_state *preinit)
179{
180 parser->buffer = NULL;
181 parser->search_list_store = NULL;
182 nameserver_list_init (&parser->nameserver_list);
183 search_list_init (&parser->search_list);
184 sort_list_init (&parser->sort_list);
185
186 if (preinit != NULL)
187 {
188 parser->template.retrans = preinit->retrans;
189 parser->template.retry = preinit->retry;
190 parser->template.options = preinit->options | RES_INIT;
191 }
192 else
193 {
194 parser->template.retrans = RES_TIMEOUT;
195 parser->template.retry = RES_DFLRETRY;
196 parser->template.options = RES_DEFAULT | RES_INIT;
197 }
198 parser->template.ndots = 1;
199}
200
201static void
202resolv_conf_parser_free (struct resolv_conf_parser *parser)
203{
204 free (parser->buffer);
205 free (parser->search_list_store);
206 nameserver_list_free (&parser->nameserver_list);
207 search_list_free (&parser->search_list);
208 sort_list_free (&parser->sort_list);
209}
210
211/* Allocate a struct sockaddr_in object on the heap, with the
212 specified address and port. */
213static struct sockaddr *
214allocate_address_v4 (struct in_addr a, uint16_t port)
215{
216 struct sockaddr_in *sa4 = malloc (sizeof (*sa4));
217 if (sa4 == NULL)
218 return NULL;
219 sa4->sin_family = AF_INET;
220 sa4->sin_addr = a;
221 sa4->sin_port = htons (port);
222 return (struct sockaddr *) sa4;
223}
224
225/* Try to obtain the domain name from the host name and store it in
226 *RESULT. Return false on memory allocation failure. If the domain
227 name cannot be determined for any other reason, write NULL to
228 *RESULT and return true. */
229static bool
230domain_from_hostname (char **result)
231{
232 char buf[256];
233 /* gethostbyname may not terminate the buffer. */
234 buf[sizeof (buf) - 1] = '\0';
235 if (__gethostname (buf, sizeof (buf) - 1) == 0)
236 {
237 char *dot = strchr (buf, '.');
238 if (dot != NULL)
239 {
240 *result = __strdup (dot + 1);
241 if (*result == NULL)
242 return false;
243 return true;
244 }
245 }
246 *result = NULL;
247 return true;
248}
249
250static void res_setoptions (struct resolv_conf_parser *, const char *options);
251
252/* Internal helper function for __res_vinit, to aid with resource
253 deallocation and error handling. Return true on success, false on
254 failure. */
255static bool
256res_vinit_1 (FILE *fp, struct resolv_conf_parser *parser)
257{
258 char *cp;
259 size_t buffer_size = 0;
260 bool haveenv = false;
261
262 /* Allow user to override the local domain definition. */
263 if ((cp = getenv ("LOCALDOMAIN")) != NULL)
264 {
265 /* The code below splits the string in place. */
266 cp = __strdup (cp);
267 if (cp == NULL)
268 return false;
269 free (parser->search_list_store);
270 parser->search_list_store = cp;
271 haveenv = true;
272
273 /* The string will be truncated as needed below. */
274 search_list_add (&parser->search_list, cp);
275
276 /* Set search list to be blank-separated strings from rest of
277 env value. Permits users of LOCALDOMAIN to still have a
278 search list, and anyone to set the one that they want to use
279 as an individual (even more important now that the rfc1535
280 stuff restricts searches). */
281 for (bool in_name = true; *cp != '\0'; cp++)
282 {
283 if (*cp == '\n')
284 {
285 *cp = '\0';
286 break;
287 }
288 else if (*cp == ' ' || *cp == '\t')
289 {
290 *cp = '\0';
291 in_name = false;
292 }
293 else if (!in_name)
294 {
295 search_list_add (&parser->search_list, cp);
296 in_name = true;
297 }
298 }
299 }
300
301#define MATCH(line, name) \
302 (!strncmp ((line), name, sizeof (name) - 1) \
303 && ((line)[sizeof (name) - 1] == ' ' \
304 || (line)[sizeof (name) - 1] == '\t'))
305
306 if (fp != NULL)
307 {
308 /* No threads use this stream. */
309 __fsetlocking (fp, FSETLOCKING_BYCALLER);
310 /* Read the config file. */
311 while (true)
312 {
313 {
314 ssize_t ret = __getline (&parser->buffer, &buffer_size, fp);
315 if (ret <= 0)
316 {
317 if (_IO_ferror_unlocked (fp))
318 return false;
319 else
320 break;
321 }
322 }
323
324 /* Skip comments. */
325 if (*parser->buffer == ';' || *parser->buffer == '#')
326 continue;
327 /* Read default domain name. */
328 if (MATCH (parser->buffer, "domain"))
329 {
330 if (haveenv)
331 /* LOCALDOMAIN overrides the configuration file. */
332 continue;
333 cp = parser->buffer + sizeof ("domain") - 1;
334 while (*cp == ' ' || *cp == '\t')
335 cp++;
336 if ((*cp == '\0') || (*cp == '\n'))
337 continue;
338
339 cp = __strdup (cp);
340 if (cp == NULL)
341 return false;
342 free (parser->search_list_store);
343 parser->search_list_store = cp;
344 search_list_clear (&parser->search_list);
345 search_list_add (&parser->search_list, cp);
346 /* Replace trailing whitespace. */
347 if ((cp = strpbrk (cp, " \t\n")) != NULL)
348 *cp = '\0';
349 continue;
350 }
351 /* Set search list. */
352 if (MATCH (parser->buffer, "search"))
353 {
354 if (haveenv)
355 /* LOCALDOMAIN overrides the configuration file. */
356 continue;
357 cp = parser->buffer + sizeof ("search") - 1;
358 while (*cp == ' ' || *cp == '\t')
359 cp++;
360 if ((*cp == '\0') || (*cp == '\n'))
361 continue;
362
363 {
364 char *p = strchr (cp, '\n');
365 if (p != NULL)
366 *p = '\0';
367 }
368 cp = __strdup (cp);
369 if (cp == NULL)
370 return false;
371 free (parser->search_list_store);
372 parser->search_list_store = cp;
373
374 /* The string is truncated below. */
375 search_list_clear (&parser->search_list);
376 search_list_add (&parser->search_list, cp);
377
378 /* Set search list to be blank-separated strings on rest
379 of line. */
380 for (bool in_name = true; *cp != '\0'; cp++)
381 {
382 if (*cp == ' ' || *cp == '\t')
383 {
384 *cp = '\0';
385 in_name = false;
386 }
387 else if (!in_name)
388 {
389 search_list_add (&parser->search_list, cp);
390 in_name = true;
391 }
392 }
393 continue;
394 }
395 /* Read nameservers to query. */
396 if (MATCH (parser->buffer, "nameserver"))
397 {
398 struct in_addr a;
399
400 cp = parser->buffer + sizeof ("nameserver") - 1;
401 while (*cp == ' ' || *cp == '\t')
402 cp++;
403
404 /* Ignore trailing contents on the name server line. */
405 {
406 char *el;
407 if ((el = strpbrk (cp, " \t\n")) != NULL)
408 *el = '\0';
409 }
410
411 struct sockaddr *sa;
412 if ((*cp != '\0') && (*cp != '\n') && __inet_aton_exact (cp, &a))
413 {
414 sa = allocate_address_v4 (a, NAMESERVER_PORT);
415 if (sa == NULL)
416 return false;
417 }
418 else
419 {
420 struct in6_addr a6;
421 char *el;
422 if ((el = strchr (cp, SCOPE_DELIMITER)) != NULL)
423 *el = '\0';
424 if ((*cp != '\0') && (__inet_pton (AF_INET6, cp, &a6) > 0))
425 {
426 struct sockaddr_in6 *sa6;
427
428 sa6 = malloc (sizeof (*sa6));
429 if (sa6 == NULL)
430 return false;
431
432 sa6->sin6_family = AF_INET6;
433 sa6->sin6_port = htons (NAMESERVER_PORT);
434 sa6->sin6_flowinfo = 0;
435 sa6->sin6_addr = a6;
436
437 sa6->sin6_scope_id = 0;
438 if (__glibc_likely (el != NULL))
439 /* Ignore errors, for backwards
440 compatibility. */
441 __inet6_scopeid_pton
442 (&a6, el + 1, &sa6->sin6_scope_id);
443 sa = (struct sockaddr *) sa6;
444 }
445 else
446 /* IPv6 address parse failure. */
447 sa = NULL;
448 }
449 if (sa != NULL)
450 {
451 const struct sockaddr **p = nameserver_list_emplace
452 (&parser->nameserver_list);
453 if (p != NULL)
454 *p = sa;
455 else
456 {
457 free (sa);
458 return false;
459 }
460 }
461 continue;
462 }
463 if (MATCH (parser->buffer, "sortlist"))
464 {
465 struct in_addr a;
466
467 cp = parser->buffer + sizeof ("sortlist") - 1;
468 while (true)
469 {
470 while (*cp == ' ' || *cp == '\t')
471 cp++;
472 if (*cp == '\0' || *cp == '\n' || *cp == ';')
473 break;
474 char *net = cp;
475 while (*cp && !is_sort_mask (*cp) && *cp != ';'
476 && isascii (*cp) && !isspace (*cp))
477 cp++;
478 char separator = *cp;
479 *cp = 0;
480 struct resolv_sortlist_entry e;
481 if (__inet_aton_exact (net, &a))
482 {
483 e.addr = a;
484 if (is_sort_mask (separator))
485 {
486 *cp++ = separator;
487 net = cp;
488 while (*cp && *cp != ';'
489 && isascii (*cp) && !isspace (*cp))
490 cp++;
491 separator = *cp;
492 *cp = 0;
493 if (__inet_aton_exact (net, &a))
494 e.mask = a.s_addr;
495 else
496 e.mask = net_mask (e.addr);
497 }
498 else
499 e.mask = net_mask (e.addr);
500 sort_list_add (&parser->sort_list, e);
501 }
502 *cp = separator;
503 }
504 continue;
505 }
506 if (MATCH (parser->buffer, "options"))
507 {
508 res_setoptions (parser, parser->buffer + sizeof ("options") - 1);
509 continue;
510 }
511 }
512 }
513 if (__glibc_unlikely (nameserver_list_size (&parser->nameserver_list) == 0))
514 {
515 const struct sockaddr **p
516 = nameserver_list_emplace (&parser->nameserver_list);
517 if (p == NULL)
518 return false;
519 *p = allocate_address_v4 (__inet_makeaddr (IN_LOOPBACKNET, 1),
520 NAMESERVER_PORT);
521 if (*p == NULL)
522 return false;
523 }
524
525 if (search_list_size (&parser->search_list) == 0)
526 {
527 char *domain;
528 if (!domain_from_hostname (&domain))
529 return false;
530 if (domain != NULL)
531 {
532 free (parser->search_list_store);
533 parser->search_list_store = domain;
534 search_list_add (&parser->search_list, domain);
535 }
536 }
537
538 if ((cp = getenv ("RES_OPTIONS")) != NULL)
539 res_setoptions (parser, cp);
540
541 if (nameserver_list_has_failed (&parser->nameserver_list)
542 || search_list_has_failed (&parser->search_list)
543 || sort_list_has_failed (&parser->sort_list))
544 {
545 __set_errno (ENOMEM);
546 return false;
547 }
548
549 return true;
550}
551
552struct resolv_conf *
553__resolv_conf_load (struct __res_state *preinit,
554 struct file_change_detection *change)
555{
556 /* Ensure that /etc/hosts.conf has been loaded (once). */
557 _res_hconf_init ();
558
559 FILE *fp = fopen (_PATH_RESCONF, "rce");
560 if (fp == NULL)
561 switch (errno)
562 {
563 case EACCES:
564 case EISDIR:
565 case ELOOP:
566 case ENOENT:
567 case ENOTDIR:
568 case EPERM:
569 /* Ignore these errors. They are persistent errors caused
570 by file system contents. */
571 break;
572 default:
573 /* Other errors refer to resource allocation problems and
574 need to be handled by the application. */
575 return NULL;
576 }
577
578 struct resolv_conf_parser parser;
579 resolv_conf_parser_init (&parser, preinit);
580
581 struct resolv_conf *conf = NULL;
582 bool ok = res_vinit_1 (fp, &parser);
583 if (ok && change != NULL)
584 /* Update the file change information if the configuration was
585 loaded successfully. */
586 ok = __file_change_detection_for_fp (change, fp);
587
588 if (ok)
589 {
590 parser.template.nameserver_list
591 = nameserver_list_begin (&parser.nameserver_list);
592 parser.template.nameserver_list_size
593 = nameserver_list_size (&parser.nameserver_list);
594 parser.template.search_list = search_list_begin (&parser.search_list);
595 parser.template.search_list_size
596 = search_list_size (&parser.search_list);
597 parser.template.sort_list = sort_list_begin (&parser.sort_list);
598 parser.template.sort_list_size = sort_list_size (&parser.sort_list);
599 conf = __resolv_conf_allocate (&parser.template);
600 }
601 resolv_conf_parser_free (&parser);
602
603 if (fp != NULL)
604 {
605 int saved_errno = errno;
606 fclose (fp);
607 __set_errno (saved_errno);
608 }
609
610 return conf;
611}
612
613/* Set up default settings. If the /etc/resolv.conf configuration
614 file exist, the values there will have precedence. Otherwise, the
615 server address is set to INADDR_LOOPBACK and the default domain
616 name comes from gethostname. The RES_OPTIONS and LOCALDOMAIN
617 environment variables can be used to override some settings.
618 Return 0 if completes successfully, -1 on error. */
619int
620__res_vinit (res_state statp, int preinit)
621{
622 struct resolv_conf *conf;
623 if (preinit && has_preinit_values (statp))
624 /* For the preinit case, we cannot use the cached configuration
625 because some settings could be different. */
626 conf = __resolv_conf_load (statp, NULL);
627 else
628 conf = __resolv_conf_get_current ();
629 if (conf == NULL)
630 return -1;
631
632 bool ok = __resolv_conf_attach (statp, conf);
633 __resolv_conf_put (conf);
634 if (ok)
635 {
636 if (preinit)
637 statp->id = res_randomid ();
638 return 0;
639 }
640 else
641 return -1;
642}
643
644static void
645res_setoptions (struct resolv_conf_parser *parser, const char *options)
646{
647 const char *cp = options;
648
649 while (*cp)
650 {
651 /* Skip leading and inner runs of spaces. */
652 while (*cp == ' ' || *cp == '\t')
653 cp++;
654 /* Search for and process individual options. */
655 if (!strncmp (cp, "ndots:", sizeof ("ndots:") - 1))
656 {
657 int i = atoi (cp + sizeof ("ndots:") - 1);
658 if (i <= RES_MAXNDOTS)
659 parser->template.ndots = i;
660 else
661 parser->template.ndots = RES_MAXNDOTS;
662 }
663 else if (!strncmp (cp, "timeout:", sizeof ("timeout:") - 1))
664 {
665 int i = atoi (cp + sizeof ("timeout:") - 1);
666 if (i <= RES_MAXRETRANS)
667 parser->template.retrans = i;
668 else
669 parser->template.retrans = RES_MAXRETRANS;
670 }
671 else if (!strncmp (cp, "attempts:", sizeof ("attempts:") - 1))
672 {
673 int i = atoi (cp + sizeof ("attempts:") - 1);
674 if (i <= RES_MAXRETRY)
675 parser->template.retry = i;
676 else
677 parser->template.retry = RES_MAXRETRY;
678 }
679 else
680 {
681 static const struct
682 {
683 char str[22];
684 uint8_t len;
685 uint8_t clear;
686 unsigned long int flag;
687 } options[] = {
688#define STRnLEN(str) str, sizeof (str) - 1
689 { STRnLEN ("rotate"), 0, RES_ROTATE },
690 { STRnLEN ("edns0"), 0, RES_USE_EDNS0 },
691 { STRnLEN ("single-request-reopen"), 0, RES_SNGLKUPREOP },
692 { STRnLEN ("single-request"), 0, RES_SNGLKUP },
693 { STRnLEN ("no_tld_query"), 0, RES_NOTLDQUERY },
694 { STRnLEN ("no-tld-query"), 0, RES_NOTLDQUERY },
695 { STRnLEN ("no-reload"), 0, RES_NORELOAD },
696 { STRnLEN ("use-vc"), 0, RES_USEVC },
697 { STRnLEN ("trust-ad"), 0, RES_TRUSTAD },
698 };
699#define noptions (sizeof (options) / sizeof (options[0]))
700 for (int i = 0; i < noptions; ++i)
701 if (strncmp (cp, options[i].str, options[i].len) == 0)
702 {
703 if (options[i].clear)
704 parser->template.options &= options[i].flag;
705 else
706 parser->template.options |= options[i].flag;
707 break;
708 }
709 }
710 /* Skip to next run of spaces. */
711 while (*cp && *cp != ' ' && *cp != '\t')
712 cp++;
713 }
714}
715
716static uint32_t
717net_mask (struct in_addr in)
718{
719 uint32_t i = ntohl (in.s_addr);
720
721 if (IN_CLASSA (i))
722 return htonl (IN_CLASSA_NET);
723 else if (IN_CLASSB (i))
724 return htonl (IN_CLASSB_NET);
725 return htonl (IN_CLASSC_NET);
726}
727