aboutsummaryrefslogtreecommitdiff
path: root/contrib/isc-dhcp/minires/res_query.c
blob: 412da65a36ca419bae1a2721819a80d9ef892f3b (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
/*
 * Copyright (c) 1988, 1993
 *    The Regents of the University of California.  All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 * 	This product includes software developed by the University of
 * 	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
 * 
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies, and that
 * the name of Digital Equipment Corporation not be used in advertising or
 * publicity pertaining to distribution of the document or software without
 * specific, written prior permission.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
 * SOFTWARE.
 */

/*
 * Portions Copyright (c) 1996-1999 by Internet Software Consortium.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
 * SOFTWARE.
 */

#if defined(LIBC_SCCS) && !defined(lint)
static const char sccsid[] = "@(#)res_query.c	8.1 (Berkeley) 6/4/93";
static const char rcsid[] = "$Id: res_query.c,v 1.4 2001/01/16 22:33:15 mellon Exp $";
#endif /* LIBC_SCCS and not lint */

#include <sys/types.h>
#include <sys/param.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <ctype.h>
#include <errno.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>

#include "minires/minires.h"
#include "arpa/nameser.h"

/* Options.  Leave them on. */
#define DEBUG

#if PACKETSZ > 1024
#define MAXPACKET	PACKETSZ
#else
#define MAXPACKET	1024
#endif

/*
 * Formulate a normal query, send, and await answer.
 * Returned answer is placed in supplied buffer "answer".
 * Perform preliminary check of answer, returning success only
 * if no error is indicated and the answer count is nonzero.
 * Return the size of the response on success, -1 on error.
 * Error number is left in H_ERRNO.
 *
 * Caller must parse answer and determine whether it answers the question.
 */
isc_result_t
res_nquery(res_state statp,
	   const char *name,	/* domain name */
	   ns_class class, ns_type type, /* class and type of query */
	   double *answer,	/* buffer to put answer */
	   unsigned anslen,
	   unsigned *ansret)	/* size of answer buffer */
{
	double buf[MAXPACKET / sizeof (double)];
	HEADER *hp = (HEADER *) answer;
	unsigned n;
	isc_result_t rcode;

	hp->rcode = NOERROR;	/* default */

#ifdef DEBUG
	if (statp->options & RES_DEBUG)
		printf(";; res_query(%s, %d, %d)\n", name, class, type);
#endif

	rcode = res_nmkquery(statp, QUERY, name, class, type, NULL, 0, NULL,
			     buf, sizeof(buf), &n);
	if (rcode != ISC_R_SUCCESS) {
#ifdef DEBUG
		if (statp->options & RES_DEBUG)
			printf(";; res_query: mkquery failed\n");
#endif
		RES_SET_H_ERRNO(statp, NO_RECOVERY);
		return rcode;
	}
	rcode = res_nsend(statp, buf, n, answer, anslen, &n);
	if (rcode != ISC_R_SUCCESS) {
#ifdef DEBUG
		if (statp->options & RES_DEBUG)
			printf(";; res_query: send error\n");
#endif
		RES_SET_H_ERRNO(statp, TRY_AGAIN);
		return rcode;
	}

	if (hp->rcode != NOERROR || ntohs(hp->ancount) == 0) {
#ifdef DEBUG
		if (statp->options & RES_DEBUG)
			printf(";; rcode = %d, ancount=%d\n", hp->rcode,
			    ntohs(hp->ancount));
#endif
		switch (hp->rcode) {
		case NXDOMAIN:
			RES_SET_H_ERRNO(statp, HOST_NOT_FOUND);
			break;
		case SERVFAIL:
			RES_SET_H_ERRNO(statp, TRY_AGAIN);
			break;
		case NOERROR:
			RES_SET_H_ERRNO(statp, NO_DATA);
			break;
		case FORMERR:
		case NOTIMP:
		case REFUSED:
		default:
			RES_SET_H_ERRNO(statp, NO_RECOVERY);
			break;
		}
		return ns_rcode_to_isc (hp -> rcode);
	}
	*ansret = n;
	return ISC_R_SUCCESS;
}

#if 0
/*
 * Formulate a normal query, send, and retrieve answer in supplied buffer.
 * Return the size of the response on success, -1 on error.
 * If enabled, implement search rules until answer or unrecoverable failure
 * is detected.  Error code, if any, is left in H_ERRNO.
 */
isc_result_t
res_nsearch(res_state statp,
	    const char *name,	/* domain name */
	    ns_class class, ns_type type, /* class and type of query */
	    double *answer,	/* buffer to put answer */
	    unsigned anslen,
	    unsigned *ansret)		/* size of answer */
{
	const char *cp, * const *domain;
	HEADER *hp = (HEADER *) answer;
	char tmp[NS_MAXDNAME];
	u_int dots;
	int trailing_dot, ret;
	int got_nodata = 0, got_servfail = 0, root_on_list = 0;
	isc_result_t rcode;

	errno = 0;
	RES_SET_H_ERRNO(statp, HOST_NOT_FOUND);  /* True if we never query. */

	dots = 0;
	for (cp = name; *cp != '\0'; cp++)
		dots += (*cp == '.');
	trailing_dot = 0;
	if (cp > name && *--cp == '.')
		trailing_dot++;

	/* If there aren't any dots, it could be a user-level alias. */
	if (!dots && (cp = res_hostalias(statp, name, tmp, sizeof tmp))!= NULL)
		return res_nquery(statp, cp, class, type,
				  answer, anslen, ansret);

	/*
	 * If there are enough dots in the name, do no searching.
	 * (The threshold can be set with the "ndots" option.)
	 */
	if (dots >= statp->ndots || trailing_dot)
		return res_nquerydomain(statp, name, NULL, class, type,
					answer, anslen, ansret);

	/*
	 * We do at least one level of search if
	 *	- there is no dot and RES_DEFNAME is set, or
	 *	- there is at least one dot, there is no trailing dot,
	 *	  and RES_DNSRCH is set.
	 */
	if ((!dots && (statp->options & RES_DEFNAMES) != 0) ||
	    (dots && !trailing_dot && (statp->options & RES_DNSRCH) != 0)) {
		int done = 0;

		for (domain = (const char * const *)statp->dnsrch;
		     *domain && !done;
		     domain++) {

			if (domain[0][0] == '\0' ||
			    (domain[0][0] == '.' && domain[0][1] == '\0'))
				root_on_list++;

			rcode = res_nquerydomain(statp, name, *domain,
						 class, type,
						 answer, anslen, &ret);
			if (rcode == ISC_R_SUCCESS && ret > 0) {
				*ansret = ret;
				return rcode;
			}

			/*
			 * If no server present, give up.
			 * If name isn't found in this domain,
			 * keep trying higher domains in the search list
			 * (if that's enabled).
			 * On a NO_DATA error, keep trying, otherwise
			 * a wildcard entry of another type could keep us
			 * from finding this entry higher in the domain.
			 * If we get some other error (negative answer or
			 * server failure), then stop searching up,
			 * but try the input name below in case it's
			 * fully-qualified.
			 */
			if (errno == ECONNREFUSED) {
				RES_SET_H_ERRNO(statp, TRY_AGAIN);
				return ISC_R_CONNREFUSED;
			}

			switch (statp->res_h_errno) {
			case NO_DATA:
				got_nodata++;
				/* FALLTHROUGH */
			case HOST_NOT_FOUND:
				/* keep trying */
				break;
			case TRY_AGAIN:
				if (hp->rcode == SERVFAIL) {
					/* try next search element, if any */
					got_servfail++;
					break;
				}
				/* FALLTHROUGH */
			default:
				/* anything else implies that we're done */
				done++;
			}

			/* if we got here for some reason other than DNSRCH,
			 * we only wanted one iteration of the loop, so stop.
			 */
			if ((statp->options & RES_DNSRCH) == 0)
				done++;
		}
	}

	/*
	 * If the name has any dots at all, and "." is not on the search
	 * list, then try an as-is query now.
	 */
	if (statp->ndots) {
		rcode = res_nquerydomain(statp, name, NULL, class, type,
					 answer, anslen, &ret);
		if (rcode == ISC_R_SUCCESS && ret > 0) {
			*ansret = ret;
			return rcode;
		}
	}

	/* if we got here, we didn't satisfy the search.
	 * if we did an initial full query, return that query's H_ERRNO
	 * (note that we wouldn't be here if that query had succeeded).
	 * else if we ever got a nodata, send that back as the reason.
	 * else send back meaningless H_ERRNO, that being the one from
	 * the last DNSRCH we did.
	 */
	if (got_nodata) {
		RES_SET_H_ERRNO(statp, NO_DATA);
		return ISC_R_NOTFOUND;
	} else if (got_servfail) {
		RES_SET_H_ERRNO(statp, TRY_AGAIN);
		return ISC_R_TIMEDOUT;
	}
	return ISC_R_UNEXPECTED;
}
#endif

/*
 * Perform a call on res_query on the concatenation of name and domain,
 * removing a trailing dot from name if domain is NULL.
 */
isc_result_t
res_nquerydomain(res_state statp,
		 const char *name,
		 const char *domain,
		 ns_class class, ns_type type,
		 double *answer,
		 unsigned anslen,
		 unsigned *ansret)
{
	char nbuf[MAXDNAME];
	const char *longname = nbuf;
	int n, d;

#ifdef DEBUG
	if (statp->options & RES_DEBUG)
		printf(";; res_nquerydomain(%s, %s, %d, %d)\n",
		       name, domain?domain:"<Nil>", class, type);
#endif
	if (domain == NULL) {
		/*
		 * Check for trailing '.';
		 * copy without '.' if present.
		 */
		n = strlen(name);
		if (n >= MAXDNAME) {
			RES_SET_H_ERRNO(statp, NO_RECOVERY);
			return ISC_R_NOSPACE;
		}
		n--;
		if (n >= 0 && name[n] == '.') {
			strncpy(nbuf, name, (unsigned)n);
			nbuf[n] = '\0';
		} else
			longname = name;
	} else {
		n = strlen(name);
		d = strlen(domain);
		if (n + d + 1 >= MAXDNAME) {
			RES_SET_H_ERRNO(statp, NO_RECOVERY);
			return ISC_R_NOSPACE;
		}
		sprintf(nbuf, "%s.%s", name, domain);
	}
	return res_nquery(statp,
			  longname, class, type, answer, anslen, ansret);
}

const char *
res_hostalias(const res_state statp, const char *name, char *dst, size_t siz) {
	char *file, *cp1, *cp2;
	char buf[BUFSIZ];
	FILE *fp;

	if (statp->options & RES_NOALIASES)
		return (NULL);
	file = getenv("HOSTALIASES");
	if (file == NULL || (fp = fopen(file, "r")) == NULL)
		return (NULL);
	setbuf(fp, NULL);
	buf[sizeof(buf) - 1] = '\0';
	while (fgets(buf, sizeof(buf), fp)) {
		for (cp1 = buf; *cp1 && !isspace(*cp1); ++cp1)
			;
		if (!*cp1)
			break;
		*cp1 = '\0';
		if (ns_samename(buf, name) == 1) {
			while (isspace(*++cp1))
				;
			if (!*cp1)
				break;
			for (cp2 = cp1 + 1; *cp2 && !isspace(*cp2); ++cp2)
				;
			*cp2 = '\0';
			strncpy(dst, cp1, siz - 1);
			dst[siz - 1] = '\0';
			fclose(fp);
			return (dst);
		}
	}
	fclose(fp);
	return (NULL);
}