Annotation of src/lib/libc/resolv/res_query.c, Revision 1.16
1.16 ! christos 1: /* $NetBSD: res_query.c,v 1.15 2014/09/16 01:30:00 christos Exp $ */
1.12 christos 2:
3: /*
4: * Portions Copyright (C) 2004, 2005, 2008 Internet Systems Consortium, Inc. ("ISC")
5: * Portions Copyright (C) 1996-2001, 2003 Internet Software Consortium.
6: *
7: * Permission to use, copy, modify, and/or distribute this software for any
8: * purpose with or without fee is hereby granted, provided that the above
9: * copyright notice and this permission notice appear in all copies.
10: *
11: * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
12: * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
13: * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
14: * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
15: * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
16: * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
17: * PERFORMANCE OF THIS SOFTWARE.
18: */
1.1 christos 19:
20: /*
21: * Copyright (c) 1988, 1993
22: * The Regents of the University of California. All rights reserved.
1.12 christos 23: *
1.1 christos 24: * Redistribution and use in source and binary forms, with or without
25: * modification, are permitted provided that the following conditions
26: * are met:
27: * 1. Redistributions of source code must retain the above copyright
28: * notice, this list of conditions and the following disclaimer.
29: * 2. Redistributions in binary form must reproduce the above copyright
30: * notice, this list of conditions and the following disclaimer in the
31: * documentation and/or other materials provided with the distribution.
1.16 ! christos 32: * 3. Neither the name of the University nor the names of its contributors
1.1 christos 33: * may be used to endorse or promote products derived from this software
34: * without specific prior written permission.
1.12 christos 35: *
1.1 christos 36: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
37: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
38: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
39: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
40: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
41: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
42: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
43: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
44: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
45: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
46: * SUCH DAMAGE.
47: */
48:
49: /*
50: * Portions Copyright (c) 1993 by Digital Equipment Corporation.
1.12 christos 51: *
1.1 christos 52: * Permission to use, copy, modify, and distribute this software for any
53: * purpose with or without fee is hereby granted, provided that the above
54: * copyright notice and this permission notice appear in all copies, and that
55: * the name of Digital Equipment Corporation not be used in advertising or
56: * publicity pertaining to distribution of the document or software without
57: * specific, written prior permission.
1.12 christos 58: *
1.1 christos 59: * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
60: * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
61: * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
62: * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
63: * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
64: * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
65: * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
66: * SOFTWARE.
67: */
68:
69: /*
70: * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
71: * Portions Copyright (c) 1996-1999 by Internet Software Consortium.
72: *
73: * Permission to use, copy, modify, and distribute this software for any
74: * purpose with or without fee is hereby granted, provided that the above
75: * copyright notice and this permission notice appear in all copies.
76: *
77: * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
78: * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
79: * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
80: * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
81: * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
82: * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
83: * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
84: */
85:
1.3 christos 86: #include <sys/cdefs.h>
1.1 christos 87: #if defined(LIBC_SCCS) && !defined(lint)
1.3 christos 88: #ifdef notdef
1.1 christos 89: static const char sccsid[] = "@(#)res_query.c 8.1 (Berkeley) 6/4/93";
1.12 christos 90: static const char rcsid[] = "Id: res_query.c,v 1.11 2008/11/14 02:36:51 marka Exp";
1.3 christos 91: #else
1.16 ! christos 92: __RCSID("$NetBSD: res_query.c,v 1.15 2014/09/16 01:30:00 christos Exp $");
1.3 christos 93: #endif
1.1 christos 94: #endif /* LIBC_SCCS and not lint */
95:
96: #include "port_before.h"
1.4 christos 97:
98: #include "namespace.h"
1.1 christos 99: #include <sys/types.h>
100: #include <sys/param.h>
101: #include <netinet/in.h>
102: #include <arpa/inet.h>
103: #include <arpa/nameser.h>
104: #include <ctype.h>
105: #include <errno.h>
106: #include <netdb.h>
107: #include <resolv.h>
108: #include <stdio.h>
109: #include <stdlib.h>
1.6 christos 110: #include <unistd.h>
1.1 christos 111: #include <string.h>
112: #include "port_after.h"
113:
1.5 christos 114: #if 0
1.4 christos 115: #ifdef __weak_alias
116: __weak_alias(res_nquery,_res_nquery)
117: __weak_alias(res_nsearch,_res_nsearch)
118: __weak_alias(res_nquerydomain,__res_nquerydomain)
119: __weak_alias(res_hostalias,__res_hostalias)
120: #endif
1.5 christos 121: #endif
1.4 christos 122:
1.1 christos 123: /* Options. Leave them on. */
1.11 christos 124: #ifndef DEBUG
1.1 christos 125: #define DEBUG
1.11 christos 126: #endif
1.1 christos 127:
128: #if PACKETSZ > 1024
129: #define MAXPACKET PACKETSZ
130: #else
131: #define MAXPACKET 1024
132: #endif
133:
1.8 christos 134: /*%
1.1 christos 135: * Formulate a normal query, send, and await answer.
136: * Returned answer is placed in supplied buffer "answer".
137: * Perform preliminary check of answer, returning success only
138: * if no error is indicated and the answer count is nonzero.
139: * Return the size of the response on success, -1 on error.
140: * Error number is left in H_ERRNO.
141: *
142: * Caller must parse answer and determine whether it answers the question.
143: */
144: int
145: res_nquery(res_state statp,
1.8 christos 146: const char *name, /*%< domain name */
147: int class, int type, /*%< class and type of query */
148: u_char *answer, /*%< buffer to put answer */
149: int anslen) /*%< size of answer buffer */
1.1 christos 150: {
151: u_char buf[MAXPACKET];
1.2 christos 152: HEADER *hp = (HEADER *)(void *)answer;
1.1 christos 153: u_int oflags;
1.10 christos 154: u_char *rdata;
1.12 christos 155: int n;
1.1 christos 156:
157: oflags = statp->_flags;
158:
159: again:
1.8 christos 160: hp->rcode = NOERROR; /*%< default */
1.1 christos 161: #ifdef DEBUG
162: if (statp->options & RES_DEBUG)
163: printf(";; res_query(%s, %d, %d)\n", name, class, type);
164: #endif
165:
166: n = res_nmkquery(statp, QUERY, name, class, type, NULL, 0, NULL,
1.14 christos 167: buf, (int)sizeof(buf));
1.1 christos 168: #ifdef RES_USE_EDNS0
169: if (n > 0 && (statp->_flags & RES_F_EDNS0ERR) == 0 &&
1.10 christos 170: (statp->options & (RES_USE_EDNS0|RES_USE_DNSSEC|RES_NSID)) != 0U) {
1.14 christos 171: n = res_nopt(statp, n, buf, (int)sizeof(buf), anslen);
1.10 christos 172: rdata = &buf[n];
173: if (n > 0 && (statp->options & RES_NSID) != 0U) {
1.14 christos 174: n = res_nopt_rdata(statp, n, buf, (int)sizeof(buf),
175: rdata, NS_OPT_NSID, 0, NULL);
1.10 christos 176: }
177: }
1.1 christos 178: #endif
179: if (n <= 0) {
180: #ifdef DEBUG
181: if (statp->options & RES_DEBUG)
182: printf(";; res_query: mkquery failed\n");
183: #endif
184: RES_SET_H_ERRNO(statp, NO_RECOVERY);
185: return (n);
186: }
1.10 christos 187:
1.1 christos 188: n = res_nsend(statp, buf, n, answer, anslen);
189: if (n < 0) {
190: #ifdef RES_USE_EDNS0
191: /* if the query choked with EDNS0, retry without EDNS0 */
192: if ((statp->options & (RES_USE_EDNS0|RES_USE_DNSSEC)) != 0U &&
193: ((oflags ^ statp->_flags) & RES_F_EDNS0ERR) != 0) {
194: statp->_flags |= RES_F_EDNS0ERR;
195: if (statp->options & RES_DEBUG)
196: printf(";; res_nquery: retry without EDNS0\n");
197: goto again;
198: }
199: #endif
200: #ifdef DEBUG
201: if (statp->options & RES_DEBUG)
202: printf(";; res_query: send error\n");
203: #endif
204: RES_SET_H_ERRNO(statp, TRY_AGAIN);
205: return (n);
206: }
207:
208: if (hp->rcode != NOERROR || ntohs(hp->ancount) == 0) {
209: #ifdef DEBUG
210: if (statp->options & RES_DEBUG)
211: printf(";; rcode = (%s), counts = an:%d ns:%d ar:%d\n",
212: p_rcode(hp->rcode),
213: ntohs(hp->ancount),
214: ntohs(hp->nscount),
215: ntohs(hp->arcount));
216: #endif
217: switch (hp->rcode) {
218: case NXDOMAIN:
219: RES_SET_H_ERRNO(statp, HOST_NOT_FOUND);
220: break;
221: case SERVFAIL:
222: RES_SET_H_ERRNO(statp, TRY_AGAIN);
223: break;
224: case NOERROR:
225: RES_SET_H_ERRNO(statp, NO_DATA);
226: break;
227: case FORMERR:
228: case NOTIMP:
229: case REFUSED:
230: default:
231: RES_SET_H_ERRNO(statp, NO_RECOVERY);
232: break;
233: }
234: return (-1);
235: }
236: return (n);
237: }
238:
1.8 christos 239: /*%
1.1 christos 240: * Formulate a normal query, send, and retrieve answer in supplied buffer.
241: * Return the size of the response on success, -1 on error.
242: * If enabled, implement search rules until answer or unrecoverable failure
243: * is detected. Error code, if any, is left in H_ERRNO.
244: */
245: int
246: res_nsearch(res_state statp,
1.8 christos 247: const char *name, /*%< domain name */
248: int class, int type, /*%< class and type of query */
249: u_char *answer, /*%< buffer to put answer */
250: int anslen) /*%< size of answer */
1.1 christos 251: {
252: const char *cp, * const *domain;
1.2 christos 253: HEADER *hp = (HEADER *)(void *)answer;
1.1 christos 254: char tmp[NS_MAXDNAME];
255: u_int dots;
256: int trailing_dot, ret, saved_herrno;
257: int got_nodata = 0, got_servfail = 0, root_on_list = 0;
258: int tried_as_is = 0;
259: int searched = 0;
260:
261: errno = 0;
1.8 christos 262: RES_SET_H_ERRNO(statp, HOST_NOT_FOUND); /*%< True if we never query. */
1.1 christos 263: dots = 0;
264: for (cp = name; *cp != '\0'; cp++)
265: dots += (*cp == '.');
266: trailing_dot = 0;
267: if (cp > name && *--cp == '.')
268: trailing_dot++;
269:
270: /* If there aren't any dots, it could be a user-level alias. */
271: if (!dots && (cp = res_hostalias(statp, name, tmp, sizeof tmp))!= NULL)
272: return (res_nquery(statp, cp, class, type, answer, anslen));
273:
274: /*
275: * If there are enough dots in the name, let's just give it a
276: * try 'as is'. The threshold can be set with the "ndots" option.
277: * Also, query 'as is', if there is a trailing dot in the name.
278: */
279: saved_herrno = -1;
280: if (dots >= statp->ndots || trailing_dot) {
281: ret = res_nquerydomain(statp, name, NULL, class, type,
282: answer, anslen);
283: if (ret > 0 || trailing_dot)
284: return (ret);
285: saved_herrno = statp->res_h_errno;
286: tried_as_is++;
287: }
288:
289: /*
290: * We do at least one level of search if
291: * - there is no dot and RES_DEFNAME is set, or
292: * - there is at least one dot, there is no trailing dot,
293: * and RES_DNSRCH is set.
294: */
295: if ((!dots && (statp->options & RES_DEFNAMES) != 0U) ||
296: (dots && !trailing_dot && (statp->options & RES_DNSRCH) != 0U)) {
297: int done = 0;
298:
299: for (domain = (const char * const *)statp->dnsrch;
300: *domain && !done;
301: domain++) {
302: searched = 1;
303:
304: if (domain[0][0] == '\0' ||
305: (domain[0][0] == '.' && domain[0][1] == '\0'))
306: root_on_list++;
307:
308: ret = res_nquerydomain(statp, name, *domain,
309: class, type,
310: answer, anslen);
311: if (ret > 0)
312: return (ret);
313:
314: /*
315: * If no server present, give up.
316: * If name isn't found in this domain,
317: * keep trying higher domains in the search list
318: * (if that's enabled).
319: * On a NO_DATA error, keep trying, otherwise
320: * a wildcard entry of another type could keep us
321: * from finding this entry higher in the domain.
322: * If we get some other error (negative answer or
323: * server failure), then stop searching up,
324: * but try the input name below in case it's
325: * fully-qualified.
326: */
327: if (errno == ECONNREFUSED) {
328: RES_SET_H_ERRNO(statp, TRY_AGAIN);
329: return (-1);
330: }
331:
332: switch (statp->res_h_errno) {
333: case NO_DATA:
334: got_nodata++;
335: /* FALLTHROUGH */
336: case HOST_NOT_FOUND:
337: /* keep trying */
338: break;
339: case TRY_AGAIN:
340: if (hp->rcode == SERVFAIL) {
341: /* try next search element, if any */
342: got_servfail++;
343: break;
344: }
345: /* FALLTHROUGH */
346: default:
347: /* anything else implies that we're done */
348: done++;
349: }
350:
351: /* if we got here for some reason other than DNSRCH,
352: * we only wanted one iteration of the loop, so stop.
353: */
354: if ((statp->options & RES_DNSRCH) == 0U)
355: done++;
356: }
357: }
358:
359: /*
360: * If the query has not already been tried as is then try it
361: * unless RES_NOTLDQUERY is set and there were no dots.
362: */
363: if ((dots || !searched || (statp->options & RES_NOTLDQUERY) == 0U) &&
364: !(tried_as_is || root_on_list)) {
365: ret = res_nquerydomain(statp, name, NULL, class, type,
366: answer, anslen);
367: if (ret > 0)
368: return (ret);
369: }
370:
371: /* if we got here, we didn't satisfy the search.
372: * if we did an initial full query, return that query's H_ERRNO
373: * (note that we wouldn't be here if that query had succeeded).
374: * else if we ever got a nodata, send that back as the reason.
375: * else send back meaningless H_ERRNO, that being the one from
376: * the last DNSRCH we did.
377: */
378: if (saved_herrno != -1)
379: RES_SET_H_ERRNO(statp, saved_herrno);
380: else if (got_nodata)
381: RES_SET_H_ERRNO(statp, NO_DATA);
382: else if (got_servfail)
383: RES_SET_H_ERRNO(statp, TRY_AGAIN);
384: return (-1);
385: }
386:
1.8 christos 387: /*%
1.1 christos 388: * Perform a call on res_query on the concatenation of name and domain,
389: * removing a trailing dot from name if domain is NULL.
390: */
391: int
392: res_nquerydomain(res_state statp,
393: const char *name,
394: const char *domain,
1.8 christos 395: int class, int type, /*%< class and type of query */
396: u_char *answer, /*%< buffer to put answer */
397: int anslen) /*%< size of answer */
1.1 christos 398: {
399: char nbuf[MAXDNAME];
400: const char *longname = nbuf;
1.14 christos 401: size_t n, d;
1.1 christos 402:
403: #ifdef DEBUG
404: if (statp->options & RES_DEBUG)
405: printf(";; res_nquerydomain(%s, %s, %d, %d)\n",
406: name, domain?domain:"<Nil>", class, type);
407: #endif
408: if (domain == NULL) {
409: /*
410: * Check for trailing '.';
411: * copy without '.' if present.
412: */
413: n = strlen(name);
414: if (n >= MAXDNAME) {
415: RES_SET_H_ERRNO(statp, NO_RECOVERY);
416: return (-1);
417: }
1.14 christos 418: if (n && name[--n] == '.') {
419: strncpy(nbuf, name, n);
1.1 christos 420: nbuf[n] = '\0';
421: } else
422: longname = name;
423: } else {
424: n = strlen(name);
425: d = strlen(domain);
426: if (n + d + 1 >= MAXDNAME) {
427: RES_SET_H_ERRNO(statp, NO_RECOVERY);
428: return (-1);
429: }
430: sprintf(nbuf, "%s.%s", name, domain);
431: }
432: return (res_nquery(statp, longname, class, type, answer, anslen));
433: }
434:
435: const char *
436: res_hostalias(const res_state statp, const char *name, char *dst, size_t siz) {
437: char *file, *cp1, *cp2;
438: char buf[BUFSIZ];
439: FILE *fp;
440:
441: if (statp->options & RES_NOALIASES)
442: return (NULL);
1.6 christos 443: /*
444: * forbid hostaliases for setuid binary, due to possible security
445: * breach.
446: */
447: if (issetugid())
448: return (NULL);
1.1 christos 449: file = getenv("HOSTALIASES");
1.15 christos 450: if (file == NULL || (fp = fopen(file, "re")) == NULL)
1.1 christos 451: return (NULL);
452: buf[sizeof(buf) - 1] = '\0';
1.14 christos 453: while (fgets(buf, (int)sizeof(buf), fp)) {
1.1 christos 454: for (cp1 = buf; *cp1 && !isspace((unsigned char)*cp1); ++cp1)
455: ;
456: if (!*cp1)
457: break;
458: *cp1 = '\0';
459: if (ns_samename(buf, name) == 1) {
460: while (isspace((unsigned char)*++cp1))
461: ;
462: if (!*cp1)
463: break;
464: for (cp2 = cp1 + 1; *cp2 &&
465: !isspace((unsigned char)*cp2); ++cp2)
466: ;
467: *cp2 = '\0';
468: strncpy(dst, cp1, siz - 1);
469: dst[siz - 1] = '\0';
470: fclose(fp);
471: return (dst);
472: }
473: }
474: fclose(fp);
475: return (NULL);
476: }
1.8 christos 477:
478: /*! \file */
CVSweb <webmaster@jp.NetBSD.org>
![[BACK]](/icons/back.gif){kind=icon}
Return to res_query.c CVS log ![[TXT]](/icons/text.gif){kind=icon}
![[DIR]](/icons/dir.gif){kind=icon}
Up to [cvs.NetBSD.org] / src / lib / libc / resolv