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-rw-r--r--src/lib/libc/net/getrrsetbyname.c507
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diff --git a/src/lib/libc/net/getrrsetbyname.c b/src/lib/libc/net/getrrsetbyname.c
new file mode 100644
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1/* $OpenBSD: getrrsetbyname.c,v 1.4 2001/08/16 18:16:43 ho 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#define ANSWER_BUFFER_SIZE 1024*64
55
56struct dns_query {
57 char *name;
58 u_int16_t type;
59 u_int16_t class;
60 struct dns_query *next;
61};
62
63struct dns_rr {
64 char *name;
65 u_int16_t type;
66 u_int16_t class;
67 u_int16_t ttl;
68 u_int16_t size;
69 void *rdata;
70 struct dns_rr *next;
71};
72
73struct dns_response {
74 HEADER header;
75 struct dns_query *query;
76 struct dns_rr *answer;
77 struct dns_rr *authority;
78 struct dns_rr *additional;
79};
80
81static struct dns_response *parse_dns_response(const char *, int);
82static struct dns_query *parse_dns_qsection(const char *, int, const char **,
83 int);
84static struct dns_rr *parse_dns_rrsection(const char *, int, const char **,
85 int);
86
87static void free_dns_query(struct dns_query *);
88static void free_dns_rr(struct dns_rr *);
89static void free_dns_response(struct dns_response *);
90
91static int count_dns_rr(struct dns_rr *, u_int16_t, u_int16_t);
92
93int
94getrrsetbyname(const char *hostname, unsigned int rdclass,
95 unsigned int rdtype, unsigned int flags,
96 struct rrsetinfo **res)
97{
98 int result;
99 struct rrsetinfo *rrset = NULL;
100 struct dns_response *response;
101 struct dns_rr *rr;
102 struct rdatainfo *rdata;
103 unsigned int length, index_ans, index_sig;
104 char answer[ANSWER_BUFFER_SIZE];
105
106 /* check for invalid class and type */
107 if (rdclass > 0xffff || rdtype > 0xffff) {
108 result = ERRSET_INVAL;
109 goto fail;
110 }
111
112 /* don't allow queries of class or type ANY */
113 if (rdclass == 0xff || rdtype == 0xff) {
114 result = ERRSET_INVAL;
115 goto fail;
116 }
117
118 /* don't allow flags yet, unimplemented */
119 if (flags) {
120 result = ERRSET_INVAL;
121 goto fail;
122 }
123
124 /* initialize resolver */
125 if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
126 result = ERRSET_FAIL;
127 goto fail;
128 }
129
130#ifdef DEBUG
131 _res.options |= RES_DEBUG;
132#endif /* DEBUG */
133
134#ifdef RES_USE_DNSSEC
135 /* turn on DNSSEC if EDNS0 is configured */
136 if (_res.options & RES_USE_EDNS0)
137 _res.options |= RES_USE_DNSSEC;
138#endif /* RES_USE_DNSEC */
139
140 /* make query */
141 length = res_query(hostname, rdclass, rdtype, answer, sizeof(answer));
142 if (length < 0) {
143 switch(h_errno) {
144 case HOST_NOT_FOUND:
145 result = ERRSET_NONAME;
146 goto fail;
147 case NO_DATA:
148 result = ERRSET_NODATA;
149 goto fail;
150 default:
151 result = ERRSET_FAIL;
152 goto fail;
153 }
154 }
155
156 /* parse result */
157 response = parse_dns_response(answer, length);
158 if (response == NULL) {
159 result = ERRSET_FAIL;
160 goto fail;
161 }
162
163 if (response->header.qdcount != 1) {
164 result = ERRSET_FAIL;
165 goto fail;
166 }
167
168 /* initialize rrset */
169 rrset = calloc(1, sizeof(struct rrsetinfo));
170 if (rrset == NULL) {
171 result = ERRSET_NOMEMORY;
172 goto fail;
173 }
174 rrset->rri_rdclass = response->query->class;
175 rrset->rri_rdtype = response->query->type;
176 rrset->rri_ttl = response->answer->ttl;
177 rrset->rri_nrdatas = response->header.ancount;
178
179 /* check for authenticated data */
180 if (response->header.ad == 1)
181 rrset->rri_flags |= RRSET_VALIDATED;
182
183 /* copy name from answer section */
184 length = strlen(response->answer->name);
185 rrset->rri_name = malloc(length + 1);
186 if (rrset->rri_name == NULL) {
187 result = ERRSET_NOMEMORY;
188 goto fail;
189 }
190 strlcpy(rrset->rri_name, response->answer->name, length + 1);
191
192 /* count answers */
193 rrset->rri_nrdatas = count_dns_rr(response->answer, rrset->rri_rdclass,
194 rrset->rri_rdtype);
195 rrset->rri_nsigs = count_dns_rr(response->answer, rrset->rri_rdclass,
196 T_SIG);
197
198 /* allocate memory for answers */
199 rrset->rri_rdatas = calloc(rrset->rri_nrdatas,
200 sizeof(struct rdatainfo));
201 if (rrset->rri_rdatas == NULL) {
202 result = ERRSET_NOMEMORY;
203 goto fail;
204 }
205
206 /* allocate memory for signatures */
207 rrset->rri_sigs = calloc(rrset->rri_nsigs, sizeof(struct rdatainfo));
208 if (rrset->rri_sigs == NULL) {
209 result = ERRSET_NOMEMORY;
210 goto fail;
211 }
212
213 /* copy answers & signatures */
214 for (rr = response->answer, index_ans = 0, index_sig = 0;
215 rr; rr = rr->next) {
216
217 rdata = NULL;
218
219 if (rr->class == rrset->rri_rdclass &&
220 rr->type == rrset->rri_rdtype)
221 rdata = &rrset->rri_rdatas[index_ans++];
222
223 if (rr->class == rrset->rri_rdclass &&
224 rr->type == T_SIG)
225 rdata = &rrset->rri_sigs[index_sig++];
226
227 if (rdata) {
228 rdata->rdi_length = rr->size;
229 rdata->rdi_data = malloc(rr->size);
230
231 if (rdata->rdi_data == NULL) {
232 result = ERRSET_NOMEMORY;
233 goto fail;
234 }
235 memcpy(rdata->rdi_data, rr->rdata, rr->size);
236 }
237 }
238
239 *res = rrset;
240 return (ERRSET_SUCCESS);
241
242fail:
243 if (rrset != NULL)
244 freerrset(rrset);
245 return (result);
246}
247
248void
249freerrset(struct rrsetinfo *rrset)
250{
251 u_int16_t i;
252
253 if (rrset == NULL)
254 return;
255
256 if (rrset->rri_rdatas) {
257 for (i = 0; i < rrset->rri_nrdatas; i++) {
258 if (rrset->rri_rdatas[i].rdi_data == NULL)
259 break;
260 free(rrset->rri_rdatas[i].rdi_data);
261 }
262 free(rrset->rri_rdatas);
263 }
264
265 if (rrset->rri_sigs) {
266 for (i = 0; i < rrset->rri_nsigs; i++) {
267 if (rrset->rri_sigs[i].rdi_data == NULL)
268 break;
269 free(rrset->rri_sigs[i].rdi_data);
270 }
271 free(rrset->rri_sigs);
272 }
273
274 if (rrset->rri_name)
275 free(rrset->rri_name);
276 free(rrset);
277}
278
279/*
280 * DNS response parsing routines
281 */
282static struct dns_response *
283parse_dns_response(const char *answer, int size)
284{
285 struct dns_response *resp;
286 const char *cp;
287
288 /* allocate memory for the response */
289 resp = calloc(1, sizeof(*resp));
290 if (resp == NULL)
291 return (NULL);
292
293 /* initialize current pointer */
294 cp = answer;
295
296 /* copy header */
297 memcpy(&resp->header, cp, HFIXEDSZ);
298 cp += HFIXEDSZ;
299
300 /* fix header byte order */
301 resp->header.qdcount = ntohs(resp->header.qdcount);
302 resp->header.ancount = ntohs(resp->header.ancount);
303 resp->header.nscount = ntohs(resp->header.nscount);
304 resp->header.arcount = ntohs(resp->header.arcount);
305
306 /* there must be at least one query */
307 if (resp->header.qdcount < 1) {
308 free_dns_response(resp);
309 return (NULL);
310 }
311
312 /* parse query section */
313 resp->query = parse_dns_qsection(answer, size, &cp,
314 resp->header.qdcount);
315 if (resp->header.qdcount && resp->query == NULL) {
316 free_dns_response(resp);
317 return (NULL);
318 }
319
320 /* parse answer section */
321 resp->answer = parse_dns_rrsection(answer, size, &cp,
322 resp->header.ancount);
323 if (resp->header.ancount && resp->answer == NULL) {
324 free_dns_response(resp);
325 return (NULL);
326 }
327
328 /* parse authority section */
329 resp->authority = parse_dns_rrsection(answer, size, &cp,
330 resp->header.nscount);
331 if (resp->header.nscount && resp->authority == NULL) {
332 free_dns_response(resp);
333 return (NULL);
334 }
335
336 /* parse additional section */
337 resp->additional = parse_dns_rrsection(answer, size, &cp,
338 resp->header.arcount);
339 if (resp->header.arcount && resp->additional == NULL) {
340 free_dns_response(resp);
341 return (NULL);
342 }
343
344 return (resp);
345}
346
347static struct dns_query *
348parse_dns_qsection(const char *answer, int size, const char **cp, int count)
349{
350 struct dns_query *head, *curr, *prev;
351 int i, length;
352 char name[MAXDNAME];
353
354 for (i = 1, head = NULL, prev = NULL; i <= count; i++, prev = curr) {
355
356 /* allocate and initialize struct */
357 curr = calloc(1, sizeof(struct dns_query));
358 if (curr == NULL) {
359 free_dns_query(head);
360 return (NULL);
361 }
362 if (head == NULL)
363 head = curr;
364 if (prev != NULL)
365 prev->next = curr;
366
367 /* name */
368 length = dn_expand(answer, answer + size, *cp, name,
369 sizeof(name));
370 if (length < 0) {
371 free_dns_query(head);
372 return (NULL);
373 }
374 curr->name = strdup(name);
375 if (curr->name == NULL) {
376 free_dns_query(head);
377 return (NULL);
378 }
379 *cp += length;
380
381 /* type */
382 curr->type = _getshort(*cp);
383 *cp += INT16SZ;
384
385 /* class */
386 curr->class = _getshort(*cp);
387 *cp += INT16SZ;
388 }
389
390 return (head);
391}
392
393static struct dns_rr *
394parse_dns_rrsection(const char *answer, int size, const char **cp, int count)
395{
396 struct dns_rr *head, *curr, *prev;
397 int i, length;
398 char name[MAXDNAME];
399
400 for (i = 1, head = NULL, prev = NULL; i <= count; i++, prev = curr) {
401
402 /* allocate and initialize struct */
403 curr = calloc(1, sizeof(struct dns_rr));
404 if (curr == NULL) {
405 free_dns_rr(head);
406 return (NULL);
407 }
408 if (head == NULL)
409 head = curr;
410 if (prev != NULL)
411 prev->next = curr;
412
413 /* name */
414 length = dn_expand(answer, answer + size, *cp, name,
415 sizeof(name));
416 if (length < 0) {
417 free_dns_rr(head);
418 return (NULL);
419 }
420 curr->name = strdup(name);
421 if (curr->name == NULL) {
422 free_dns_rr(head);
423 return (NULL);
424 }
425 *cp += length;
426
427 /* type */
428 curr->type = _getshort(*cp);
429 *cp += INT16SZ;
430
431 /* class */
432 curr->class = _getshort(*cp);
433 *cp += INT16SZ;
434
435 /* ttl */
436 curr->ttl = _getlong(*cp);
437 *cp += INT32SZ;
438
439 /* rdata size */
440 curr->size = _getshort(*cp);
441 *cp += INT16SZ;
442
443 /* rdata itself */
444 curr->rdata = malloc(curr->size);
445 if (curr->rdata == NULL) {
446 free_dns_rr(head);
447 return (NULL);
448 }
449 memcpy(curr->rdata, *cp, curr->size);
450 *cp += curr->size;
451 }
452
453 return (head);
454}
455
456static void
457free_dns_query(struct dns_query *p)
458{
459 if (p == NULL)
460 return;
461
462 if (p->name)
463 free(p->name);
464 free_dns_query(p->next);
465 free(p);
466}
467
468static void
469free_dns_rr(struct dns_rr *p)
470{
471 if (p == NULL)
472 return;
473
474 if (p->name)
475 free(p->name);
476 if (p->rdata)
477 free(p->rdata);
478 free_dns_rr(p->next);
479 free(p);
480}
481
482static void
483free_dns_response(struct dns_response *p)
484{
485 if (p == NULL)
486 return;
487
488 free_dns_query(p->query);
489 free_dns_rr(p->answer);
490 free_dns_rr(p->authority);
491 free_dns_rr(p->additional);
492 free(p);
493}
494
495static int
496count_dns_rr(struct dns_rr *p, u_int16_t class, u_int16_t type)
497{
498 int n = 0;
499
500 while(p) {
501 if (p->class == class && p->type == type)
502 n++;
503 p = p->next;
504 }
505
506 return (n);
507}