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diff --git a/src/lib/libc/net/getrrsetbyname.c b/src/lib/libc/net/getrrsetbyname.c
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1/* $OpenBSD: getrrsetbyname.c,v 1.11 2007/10/11 18:36:41 jakob Exp $ */
2
3/*
4 * Copyright (c) 2001 Jakob Schlyter. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 *
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29/*
30 * Portions Copyright (c) 1999-2001 Internet Software Consortium.
31 *
32 * Permission to use, copy, modify, and distribute this software for any
33 * purpose with or without fee is hereby granted, provided that the above
34 * copyright notice and this permission notice appear in all copies.
35 *
36 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM
37 * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
38 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
39 * INTERNET SOFTWARE CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT,
40 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
41 * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
42 * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
43 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
44 */
45
46#include <sys/types.h>
47#include <netinet/in.h>
48#include <arpa/nameser.h>
49#include <netdb.h>
50#include <resolv.h>
51#include <stdlib.h>
52#include <string.h>
53
54#include "thread_private.h"
55
56#define ANSWER_BUFFER_SIZE 1024*64
57
58struct dns_query {
59 char *name;
60 u_int16_t type;
61 u_int16_t class;
62 struct dns_query *next;
63};
64
65struct dns_rr {
66 char *name;
67 u_int16_t type;
68 u_int16_t class;
69 u_int16_t ttl;
70 u_int16_t size;
71 void *rdata;
72 struct dns_rr *next;
73};
74
75struct dns_response {
76 HEADER header;
77 struct dns_query *query;
78 struct dns_rr *answer;
79 struct dns_rr *authority;
80 struct dns_rr *additional;
81};
82
83static struct dns_response *parse_dns_response(const u_char *, int);
84static struct dns_query *parse_dns_qsection(const u_char *, int,
85 const u_char **, int);
86static struct dns_rr *parse_dns_rrsection(const u_char *, int, const u_char **,
87 int);
88
89static void free_dns_query(struct dns_query *);
90static void free_dns_rr(struct dns_rr *);
91static void free_dns_response(struct dns_response *);
92
93static int count_dns_rr(struct dns_rr *, u_int16_t, u_int16_t);
94
95int
96getrrsetbyname(const char *hostname, unsigned int rdclass,
97 unsigned int rdtype, unsigned int flags,
98 struct rrsetinfo **res)
99{
100 struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
101 int result;
102 struct rrsetinfo *rrset = NULL;
103 struct dns_response *response = NULL;
104 struct dns_rr *rr;
105 struct rdatainfo *rdata;
106 int length;
107 unsigned int index_ans, index_sig;
108 u_char answer[ANSWER_BUFFER_SIZE];
109
110 /* check for invalid class and type */
111 if (rdclass > 0xffff || rdtype > 0xffff) {
112 result = ERRSET_INVAL;
113 goto fail;
114 }
115
116 /* don't allow queries of class or type ANY */
117 if (rdclass == 0xff || rdtype == 0xff) {
118 result = ERRSET_INVAL;
119 goto fail;
120 }
121
122 /* don't allow flags yet, unimplemented */
123 if (flags) {
124 result = ERRSET_INVAL;
125 goto fail;
126 }
127
128 /* initialize resolver */
129 if (_res_init(0) == -1) {
130 result = ERRSET_FAIL;
131 goto fail;
132 }
133
134#ifdef DEBUG
135 _resp->options |= RES_DEBUG;
136#endif /* DEBUG */
137
138#ifdef RES_USE_DNSSEC
139 /* turn on DNSSEC if EDNS0 is configured */
140 if (_resp->options & RES_USE_EDNS0)
141 _resp->options |= RES_USE_DNSSEC;
142#endif /* RES_USE_DNSEC */
143
144 /* make query */
145 length = res_query(hostname, (signed int) rdclass, (signed int) rdtype,
146 answer, sizeof(answer));
147 if (length < 0) {
148 switch(h_errno) {
149 case HOST_NOT_FOUND:
150 result = ERRSET_NONAME;
151 goto fail;
152 case NO_DATA:
153 result = ERRSET_NODATA;
154 goto fail;
155 default:
156 result = ERRSET_FAIL;
157 goto fail;
158 }
159 }
160
161 /* parse result */
162 response = parse_dns_response(answer, length);
163 if (response == NULL) {
164 result = ERRSET_FAIL;
165 goto fail;
166 }
167
168 if (response->header.qdcount != 1) {
169 result = ERRSET_FAIL;
170 goto fail;
171 }
172
173 /* initialize rrset */
174 rrset = calloc(1, sizeof(struct rrsetinfo));
175 if (rrset == NULL) {
176 result = ERRSET_NOMEMORY;
177 goto fail;
178 }
179 rrset->rri_rdclass = response->query->class;
180 rrset->rri_rdtype = response->query->type;
181 rrset->rri_ttl = response->answer->ttl;
182 rrset->rri_nrdatas = response->header.ancount;
183
184 /* check for authenticated data */
185 if (response->header.ad == 1)
186 rrset->rri_flags |= RRSET_VALIDATED;
187
188 /* copy name from answer section */
189 rrset->rri_name = strdup(response->answer->name);
190 if (rrset->rri_name == NULL) {
191 result = ERRSET_NOMEMORY;
192 goto fail;
193 }
194
195 /* count answers */
196 rrset->rri_nrdatas = count_dns_rr(response->answer, rrset->rri_rdclass,
197 rrset->rri_rdtype);
198 rrset->rri_nsigs = count_dns_rr(response->answer, rrset->rri_rdclass,
199 T_RRSIG);
200
201 /* allocate memory for answers */
202 rrset->rri_rdatas = calloc(rrset->rri_nrdatas,
203 sizeof(struct rdatainfo));
204 if (rrset->rri_rdatas == NULL) {
205 result = ERRSET_NOMEMORY;
206 goto fail;
207 }
208
209 /* allocate memory for signatures */
210 rrset->rri_sigs = calloc(rrset->rri_nsigs, sizeof(struct rdatainfo));
211 if (rrset->rri_sigs == NULL) {
212 result = ERRSET_NOMEMORY;
213 goto fail;
214 }
215
216 /* copy answers & signatures */
217 for (rr = response->answer, index_ans = 0, index_sig = 0;
218 rr; rr = rr->next) {
219
220 rdata = NULL;
221
222 if (rr->class == rrset->rri_rdclass &&
223 rr->type == rrset->rri_rdtype)
224 rdata = &rrset->rri_rdatas[index_ans++];
225
226 if (rr->class == rrset->rri_rdclass &&
227 rr->type == T_RRSIG)
228 rdata = &rrset->rri_sigs[index_sig++];
229
230 if (rdata) {
231 rdata->rdi_length = rr->size;
232 rdata->rdi_data = malloc(rr->size);
233
234 if (rdata->rdi_data == NULL) {
235 result = ERRSET_NOMEMORY;
236 goto fail;
237 }
238 memcpy(rdata->rdi_data, rr->rdata, rr->size);
239 }
240 }
241 free_dns_response(response);
242
243 *res = rrset;
244 return (ERRSET_SUCCESS);
245
246fail:
247 if (rrset != NULL)
248 freerrset(rrset);
249 if (response != NULL)
250 free_dns_response(response);
251 return (result);
252}
253
254void
255freerrset(struct rrsetinfo *rrset)
256{
257 u_int16_t i;
258
259 if (rrset == NULL)
260 return;
261
262 if (rrset->rri_rdatas) {
263 for (i = 0; i < rrset->rri_nrdatas; i++) {
264 if (rrset->rri_rdatas[i].rdi_data == NULL)
265 break;
266 free(rrset->rri_rdatas[i].rdi_data);
267 }
268 free(rrset->rri_rdatas);
269 }
270
271 if (rrset->rri_sigs) {
272 for (i = 0; i < rrset->rri_nsigs; i++) {
273 if (rrset->rri_sigs[i].rdi_data == NULL)
274 break;
275 free(rrset->rri_sigs[i].rdi_data);
276 }
277 free(rrset->rri_sigs);
278 }
279
280 if (rrset->rri_name)
281 free(rrset->rri_name);
282 free(rrset);
283}
284
285/*
286 * DNS response parsing routines
287 */
288static struct dns_response *
289parse_dns_response(const u_char *answer, int size)
290{
291 struct dns_response *resp;
292 const u_char *cp;
293
294 /* allocate memory for the response */
295 resp = calloc(1, sizeof(*resp));
296 if (resp == NULL)
297 return (NULL);
298
299 /* initialize current pointer */
300 cp = answer;
301
302 /* copy header */
303 memcpy(&resp->header, cp, HFIXEDSZ);
304 cp += HFIXEDSZ;
305
306 /* fix header byte order */
307 resp->header.qdcount = ntohs(resp->header.qdcount);
308 resp->header.ancount = ntohs(resp->header.ancount);
309 resp->header.nscount = ntohs(resp->header.nscount);
310 resp->header.arcount = ntohs(resp->header.arcount);
311
312 /* there must be at least one query */
313 if (resp->header.qdcount < 1) {
314 free_dns_response(resp);
315 return (NULL);
316 }
317
318 /* parse query section */
319 resp->query = parse_dns_qsection(answer, size, &cp,
320 resp->header.qdcount);
321 if (resp->header.qdcount && resp->query == NULL) {
322 free_dns_response(resp);
323 return (NULL);
324 }
325
326 /* parse answer section */
327 resp->answer = parse_dns_rrsection(answer, size, &cp,
328 resp->header.ancount);
329 if (resp->header.ancount && resp->answer == NULL) {
330 free_dns_response(resp);
331 return (NULL);
332 }
333
334 /* parse authority section */
335 resp->authority = parse_dns_rrsection(answer, size, &cp,
336 resp->header.nscount);
337 if (resp->header.nscount && resp->authority == NULL) {
338 free_dns_response(resp);
339 return (NULL);
340 }
341
342 /* parse additional section */
343 resp->additional = parse_dns_rrsection(answer, size, &cp,
344 resp->header.arcount);
345 if (resp->header.arcount && resp->additional == NULL) {
346 free_dns_response(resp);
347 return (NULL);
348 }
349
350 return (resp);
351}
352
353static struct dns_query *
354parse_dns_qsection(const u_char *answer, int size, const u_char **cp, int count)
355{
356 struct dns_query *head, *curr, *prev;
357 int i, length;
358 char name[MAXDNAME];
359
360 for (i = 1, head = NULL, prev = NULL; i <= count; i++, prev = curr) {
361
362 /* allocate and initialize struct */
363 curr = calloc(1, sizeof(struct dns_query));
364 if (curr == NULL) {
365 free_dns_query(head);
366 return (NULL);
367 }
368 if (head == NULL)
369 head = curr;
370 if (prev != NULL)
371 prev->next = curr;
372
373 /* name */
374 length = dn_expand(answer, answer + size, *cp, name,
375 sizeof(name));
376 if (length < 0) {
377 free_dns_query(head);
378 return (NULL);
379 }
380 curr->name = strdup(name);
381 if (curr->name == NULL) {
382 free_dns_query(head);
383 return (NULL);
384 }
385 *cp += length;
386
387 /* type */
388 curr->type = _getshort(*cp);
389 *cp += INT16SZ;
390
391 /* class */
392 curr->class = _getshort(*cp);
393 *cp += INT16SZ;
394 }
395
396 return (head);
397}
398
399static struct dns_rr *
400parse_dns_rrsection(const u_char *answer, int size, const u_char **cp,
401 int count)
402{
403 struct dns_rr *head, *curr, *prev;
404 int i, length;
405 char name[MAXDNAME];
406
407 for (i = 1, head = NULL, prev = NULL; i <= count; i++, prev = curr) {
408
409 /* allocate and initialize struct */
410 curr = calloc(1, sizeof(struct dns_rr));
411 if (curr == NULL) {
412 free_dns_rr(head);
413 return (NULL);
414 }
415 if (head == NULL)
416 head = curr;
417 if (prev != NULL)
418 prev->next = curr;
419
420 /* name */
421 length = dn_expand(answer, answer + size, *cp, name,
422 sizeof(name));
423 if (length < 0) {
424 free_dns_rr(head);
425 return (NULL);
426 }
427 curr->name = strdup(name);
428 if (curr->name == NULL) {
429 free_dns_rr(head);
430 return (NULL);
431 }
432 *cp += length;
433
434 /* type */
435 curr->type = _getshort(*cp);
436 *cp += INT16SZ;
437
438 /* class */
439 curr->class = _getshort(*cp);
440 *cp += INT16SZ;
441
442 /* ttl */
443 curr->ttl = _getlong(*cp);
444 *cp += INT32SZ;
445
446 /* rdata size */
447 curr->size = _getshort(*cp);
448 *cp += INT16SZ;
449
450 /* rdata itself */
451 curr->rdata = malloc(curr->size);
452 if (curr->rdata == NULL) {
453 free_dns_rr(head);
454 return (NULL);
455 }
456 memcpy(curr->rdata, *cp, curr->size);
457 *cp += curr->size;
458 }
459
460 return (head);
461}
462
463static void
464free_dns_query(struct dns_query *p)
465{
466 if (p == NULL)
467 return;
468
469 if (p->name)
470 free(p->name);
471 free_dns_query(p->next);
472 free(p);
473}
474
475static void
476free_dns_rr(struct dns_rr *p)
477{
478 if (p == NULL)
479 return;
480
481 if (p->name)
482 free(p->name);
483 if (p->rdata)
484 free(p->rdata);
485 free_dns_rr(p->next);
486 free(p);
487}
488
489static void
490free_dns_response(struct dns_response *p)
491{
492 if (p == NULL)
493 return;
494
495 free_dns_query(p->query);
496 free_dns_rr(p->answer);
497 free_dns_rr(p->authority);
498 free_dns_rr(p->additional);
499 free(p);
500}
501
502static int
503count_dns_rr(struct dns_rr *p, u_int16_t class, u_int16_t type)
504{
505 int n = 0;
506
507 while(p) {
508 if (p->class == class && p->type == type)
509 n++;
510 p = p->next;
511 }
512
513 return (n);
514}