source: branches/samba-3.5.x/source4/heimdal/lib/roken/resolve.c

Last change on this file was 414, checked in by Herwig Bauernfeind, 16 years ago

Samba 3.5.0: Initial import
File size: 16.6 KB
Line 
1/*
2 * Copyright (c) 1995 - 2006 Kungliga Tekniska Högskolan
3 * (Royal Institute of Technology, Stockholm, Sweden).
4 * 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 * 3. Neither the name of the Institute nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34
35#include <config.h>
36
37#include "roken.h"
38#ifdef HAVE_ARPA_NAMESER_H
39#include <arpa/nameser.h>
40#endif
41#ifdef HAVE_RESOLV_H
42#include <resolv.h>
43#endif
44#ifdef HAVE_DNS_H
45#include <dns.h>
46#endif
47#include "resolve.h"
48
49#include <assert.h>
50
51RCSID("$Id$");
52
53#ifdef _AIX /* AIX have broken res_nsearch() in 5.1 (5.0 also ?) */
54#undef HAVE_RES_NSEARCH
55#endif
56
57#define DECL(X) {#X, rk_ns_t_##X}
58
59static struct stot{
60 const char *name;
61 int type;
62}stot[] = {
63 DECL(a),
64 DECL(aaaa),
65 DECL(ns),
66 DECL(cname),
67 DECL(soa),
68 DECL(ptr),
69 DECL(mx),
70 DECL(txt),
71 DECL(afsdb),
72 DECL(sig),
73 DECL(key),
74 DECL(srv),
75 DECL(naptr),
76 DECL(sshfp),
77 DECL(ds),
78 {NULL, 0}
79};
80
81int _resolve_debug = 0;
82
83int ROKEN_LIB_FUNCTION
84rk_dns_string_to_type(const char *name)
85{
86 struct stot *p = stot;
87 for(p = stot; p->name; p++)
88 if(strcasecmp(name, p->name) == 0)
89 return p->type;
90 return -1;
91}
92
93const char * ROKEN_LIB_FUNCTION
94rk_dns_type_to_string(int type)
95{
96 struct stot *p = stot;
97 for(p = stot; p->name; p++)
98 if(type == p->type)
99 return p->name;
100 return NULL;
101}
102
103#if (defined(HAVE_RES_SEARCH) || defined(HAVE_RES_NSEARCH)) && defined(HAVE_DN_EXPAND)
104
105static void
106dns_free_rr(struct rk_resource_record *rr)
107{
108 if(rr->domain)
109 free(rr->domain);
110 if(rr->u.data)
111 free(rr->u.data);
112 free(rr);
113}
114
115void ROKEN_LIB_FUNCTION
116rk_dns_free_data(struct rk_dns_reply *r)
117{
118 struct rk_resource_record *rr;
119 if(r->q.domain)
120 free(r->q.domain);
121 for(rr = r->head; rr;){
122 struct rk_resource_record *tmp = rr;
123 rr = rr->next;
124 dns_free_rr(tmp);
125 }
126 free (r);
127}
128
129static int
130parse_record(const unsigned char *data, const unsigned char *end_data,
131 const unsigned char **pp, struct rk_resource_record **ret_rr)
132{
133 struct rk_resource_record *rr;
134 int type, class, ttl;
135 unsigned size;
136 int status;
137 char host[MAXDNAME];
138 const unsigned char *p = *pp;
139
140 *ret_rr = NULL;
141
142 status = dn_expand(data, end_data, p, host, sizeof(host));
143 if(status < 0)
144 return -1;
145 if (p + status + 10 > end_data)
146 return -1;
147
148 p += status;
149 type = (p[0] << 8) | p[1];
150 p += 2;
151 class = (p[0] << 8) | p[1];
152 p += 2;
153 ttl = (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3];
154 p += 4;
155 size = (p[0] << 8) | p[1];
156 p += 2;
157
158 if (p + size > end_data)
159 return -1;
160
161 rr = calloc(1, sizeof(*rr));
162 if(rr == NULL)
163 return -1;
164 rr->domain = strdup(host);
165 if(rr->domain == NULL) {
166 dns_free_rr(rr);
167 return -1;
168 }
169 rr->type = type;
170 rr->class = class;
171 rr->ttl = ttl;
172 rr->size = size;
173 switch(type){
174 case rk_ns_t_ns:
175 case rk_ns_t_cname:
176 case rk_ns_t_ptr:
177 status = dn_expand(data, end_data, p, host, sizeof(host));
178 if(status < 0) {
179 dns_free_rr(rr);
180 return -1;
181 }
182 rr->u.txt = strdup(host);
183 if(rr->u.txt == NULL) {
184 dns_free_rr(rr);
185 return -1;
186 }
187 break;
188 case rk_ns_t_mx:
189 case rk_ns_t_afsdb:{
190 size_t hostlen;
191
192 status = dn_expand(data, end_data, p + 2, host, sizeof(host));
193 if(status < 0){
194 dns_free_rr(rr);
195 return -1;
196 }
197 if (status + 2 > size) {
198 dns_free_rr(rr);
199 return -1;
200 }
201
202 hostlen = strlen(host);
203 rr->u.mx = (struct mx_record*)malloc(sizeof(struct mx_record) +
204 hostlen);
205 if(rr->u.mx == NULL) {
206 dns_free_rr(rr);
207 return -1;
208 }
209 rr->u.mx->preference = (p[0] << 8) | p[1];
210 strlcpy(rr->u.mx->domain, host, hostlen + 1);
211 break;
212 }
213 case rk_ns_t_srv:{
214 size_t hostlen;
215 status = dn_expand(data, end_data, p + 6, host, sizeof(host));
216 if(status < 0){
217 dns_free_rr(rr);
218 return -1;
219 }
220 if (status + 6 > size) {
221 dns_free_rr(rr);
222 return -1;
223 }
224
225 hostlen = strlen(host);
226 rr->u.srv =
227 (struct srv_record*)malloc(sizeof(struct srv_record) +
228 hostlen);
229 if(rr->u.srv == NULL) {
230 dns_free_rr(rr);
231 return -1;
232 }
233 rr->u.srv->priority = (p[0] << 8) | p[1];
234 rr->u.srv->weight = (p[2] << 8) | p[3];
235 rr->u.srv->port = (p[4] << 8) | p[5];
236 strlcpy(rr->u.srv->target, host, hostlen + 1);
237 break;
238 }
239 case rk_ns_t_txt:{
240 if(size == 0 || size < *p + 1) {
241 dns_free_rr(rr);
242 return -1;
243 }
244 rr->u.txt = (char*)malloc(*p + 1);
245 if(rr->u.txt == NULL) {
246 dns_free_rr(rr);
247 return -1;
248 }
249 strncpy(rr->u.txt, (const char*)(p + 1), *p);
250 rr->u.txt[*p] = '\0';
251 break;
252 }
253 case rk_ns_t_key : {
254 size_t key_len;
255
256 if (size < 4) {
257 dns_free_rr(rr);
258 return -1;
259 }
260
261 key_len = size - 4;
262 rr->u.key = malloc (sizeof(*rr->u.key) + key_len - 1);
263 if (rr->u.key == NULL) {
264 dns_free_rr(rr);
265 return -1;
266 }
267
268 rr->u.key->flags = (p[0] << 8) | p[1];
269 rr->u.key->protocol = p[2];
270 rr->u.key->algorithm = p[3];
271 rr->u.key->key_len = key_len;
272 memcpy (rr->u.key->key_data, p + 4, key_len);
273 break;
274 }
275 case rk_ns_t_sig : {
276 size_t sig_len, hostlen;
277
278 if(size <= 18) {
279 dns_free_rr(rr);
280 return -1;
281 }
282 status = dn_expand (data, end_data, p + 18, host, sizeof(host));
283 if (status < 0) {
284 dns_free_rr(rr);
285 return -1;
286 }
287 if (status + 18 > size) {
288 dns_free_rr(rr);
289 return -1;
290 }
291
292 /* the signer name is placed after the sig_data, to make it
293 easy to free this structure; the size calculation below
294 includes the zero-termination if the structure itself.
295 don't you just love C?
296 */
297 sig_len = size - 18 - status;
298 hostlen = strlen(host);
299 rr->u.sig = malloc(sizeof(*rr->u.sig)
300 + hostlen + sig_len);
301 if (rr->u.sig == NULL) {
302 dns_free_rr(rr);
303 return -1;
304 }
305 rr->u.sig->type = (p[0] << 8) | p[1];
306 rr->u.sig->algorithm = p[2];
307 rr->u.sig->labels = p[3];
308 rr->u.sig->orig_ttl = (p[4] << 24) | (p[5] << 16)
309 | (p[6] << 8) | p[7];
310 rr->u.sig->sig_expiration = (p[8] << 24) | (p[9] << 16)
311 | (p[10] << 8) | p[11];
312 rr->u.sig->sig_inception = (p[12] << 24) | (p[13] << 16)
313 | (p[14] << 8) | p[15];
314 rr->u.sig->key_tag = (p[16] << 8) | p[17];
315 rr->u.sig->sig_len = sig_len;
316 memcpy (rr->u.sig->sig_data, p + 18 + status, sig_len);
317 rr->u.sig->signer = &rr->u.sig->sig_data[sig_len];
318 strlcpy(rr->u.sig->signer, host, hostlen + 1);
319 break;
320 }
321
322 case rk_ns_t_cert : {
323 size_t cert_len;
324
325 if (size < 5) {
326 dns_free_rr(rr);
327 return -1;
328 }
329
330 cert_len = size - 5;
331 rr->u.cert = malloc (sizeof(*rr->u.cert) + cert_len - 1);
332 if (rr->u.cert == NULL) {
333 dns_free_rr(rr);
334 return -1;
335 }
336
337 rr->u.cert->type = (p[0] << 8) | p[1];
338 rr->u.cert->tag = (p[2] << 8) | p[3];
339 rr->u.cert->algorithm = p[4];
340 rr->u.cert->cert_len = cert_len;
341 memcpy (rr->u.cert->cert_data, p + 5, cert_len);
342 break;
343 }
344 case rk_ns_t_sshfp : {
345 size_t sshfp_len;
346
347 if (size < 2) {
348 dns_free_rr(rr);
349 return -1;
350 }
351
352 sshfp_len = size - 2;
353
354 rr->u.sshfp = malloc (sizeof(*rr->u.sshfp) + sshfp_len - 1);
355 if (rr->u.sshfp == NULL) {
356 dns_free_rr(rr);
357 return -1;
358 }
359
360 rr->u.sshfp->algorithm = p[0];
361 rr->u.sshfp->type = p[1];
362 rr->u.sshfp->sshfp_len = sshfp_len;
363 memcpy (rr->u.sshfp->sshfp_data, p + 2, sshfp_len);
364 break;
365 }
366 case rk_ns_t_ds: {
367 size_t digest_len;
368
369 if (size < 4) {
370 dns_free_rr(rr);
371 return -1;
372 }
373
374 digest_len = size - 4;
375
376 rr->u.ds = malloc (sizeof(*rr->u.ds) + digest_len - 1);
377 if (rr->u.ds == NULL) {
378 dns_free_rr(rr);
379 return -1;
380 }
381
382 rr->u.ds->key_tag = (p[0] << 8) | p[1];
383 rr->u.ds->algorithm = p[2];
384 rr->u.ds->digest_type = p[3];
385 rr->u.ds->digest_len = digest_len;
386 memcpy (rr->u.ds->digest_data, p + 4, digest_len);
387 break;
388 }
389 default:
390 rr->u.data = (unsigned char*)malloc(size);
391 if(size != 0 && rr->u.data == NULL) {
392 dns_free_rr(rr);
393 return -1;
394 }
395 if (size)
396 memcpy(rr->u.data, p, size);
397 }
398 *pp = p + size;
399 *ret_rr = rr;
400
401 return 0;
402}
403
404#ifndef TEST_RESOLVE
405static
406#endif
407struct rk_dns_reply*
408parse_reply(const unsigned char *data, size_t len)
409{
410 const unsigned char *p;
411 int status;
412 int i;
413 char host[MAXDNAME];
414 const unsigned char *end_data = data + len;
415 struct rk_dns_reply *r;
416 struct rk_resource_record **rr;
417
418 r = calloc(1, sizeof(*r));
419 if (r == NULL)
420 return NULL;
421
422 p = data;
423
424 r->h.id = (p[0] << 8) | p[1];
425 r->h.flags = 0;
426 if (p[2] & 0x01)
427 r->h.flags |= rk_DNS_HEADER_RESPONSE_FLAG;
428 r->h.opcode = (p[2] >> 1) & 0xf;
429 if (p[2] & 0x20)
430 r->h.flags |= rk_DNS_HEADER_AUTHORITIVE_ANSWER;
431 if (p[2] & 0x40)
432 r->h.flags |= rk_DNS_HEADER_TRUNCATED_MESSAGE;
433 if (p[2] & 0x80)
434 r->h.flags |= rk_DNS_HEADER_RECURSION_DESIRED;
435 if (p[3] & 0x01)
436 r->h.flags |= rk_DNS_HEADER_RECURSION_AVAILABLE;
437 if (p[3] & 0x04)
438 r->h.flags |= rk_DNS_HEADER_AUTHORITIVE_ANSWER;
439 if (p[3] & 0x08)
440 r->h.flags |= rk_DNS_HEADER_CHECKING_DISABLED;
441 r->h.response_code = (p[3] >> 4) & 0xf;
442 r->h.qdcount = (p[4] << 8) | p[5];
443 r->h.ancount = (p[6] << 8) | p[7];
444 r->h.nscount = (p[8] << 8) | p[9];
445 r->h.arcount = (p[10] << 8) | p[11];
446
447 p += 12;
448
449 if(r->h.qdcount != 1) {
450 free(r);
451 return NULL;
452 }
453 status = dn_expand(data, end_data, p, host, sizeof(host));
454 if(status < 0){
455 rk_dns_free_data(r);
456 return NULL;
457 }
458 r->q.domain = strdup(host);
459 if(r->q.domain == NULL) {
460 rk_dns_free_data(r);
461 return NULL;
462 }
463 if (p + status + 4 > end_data) {
464 rk_dns_free_data(r);
465 return NULL;
466 }
467 p += status;
468 r->q.type = (p[0] << 8 | p[1]);
469 p += 2;
470 r->q.class = (p[0] << 8 | p[1]);
471 p += 2;
472
473 rr = &r->head;
474 for(i = 0; i < r->h.ancount; i++) {
475 if(parse_record(data, end_data, &p, rr) != 0) {
476 rk_dns_free_data(r);
477 return NULL;
478 }
479 rr = &(*rr)->next;
480 }
481 for(i = 0; i < r->h.nscount; i++) {
482 if(parse_record(data, end_data, &p, rr) != 0) {
483 rk_dns_free_data(r);
484 return NULL;
485 }
486 rr = &(*rr)->next;
487 }
488 for(i = 0; i < r->h.arcount; i++) {
489 if(parse_record(data, end_data, &p, rr) != 0) {
490 rk_dns_free_data(r);
491 return NULL;
492 }
493 rr = &(*rr)->next;
494 }
495 *rr = NULL;
496 return r;
497}
498
499#ifdef HAVE_RES_NSEARCH
500#ifdef HAVE_RES_NDESTROY
501#define rk_res_free(x) res_ndestroy(x)
502#else
503#define rk_res_free(x) res_nclose(x)
504#endif
505#endif
506
507#if defined(HAVE_DNS_SEARCH)
508#define resolve_search(h,n,c,t,r,l) \
509 ((int)dns_search(h,n,c,t,r,l,(struct sockaddr *)&from,&fromsize))
510#define resolve_free_handle(h) dns_free(h)
511#elif defined(HAVE_RES_NSEARCH)
512#define resolve_search(h,n,c,t,r,l) res_nsearch(h,n,c,t,r,l)
513#define resolve_free_handle(h) rk_res_free(h);
514#else
515#define resolve_search(h,n,c,t,r,l) res_search(n,c,t,r,l)
516#define handle 0
517#define resolve_free_handle(h)
518#endif
519
520
521static struct rk_dns_reply *
522dns_lookup_int(const char *domain, int rr_class, int rr_type)
523{
524 struct rk_dns_reply *r;
525 void *reply = NULL;
526 int size;
527 int len;
528#if defined(HAVE_DNS_SEARCH)
529 struct sockaddr_storage from;
530 uint32_t fromsize = sizeof(from);
531 dns_handle_t handle;
532
533 handle = dns_open(NULL);
534 if (handle == NULL)
535 return NULL;
536#elif defined(HAVE_RES_NSEARCH)
537 struct __res_state state;
538 struct __res_state *handle = &state;
539
540 memset(&state, 0, sizeof(state));
541 if(res_ninit(handle))
542 return NULL; /* is this the best we can do? */
543#endif
544
545 size = 0;
546 len = 1000;
547 do {
548 if (reply) {
549 free(reply);
550 reply = NULL;
551 }
552 if (size <= len)
553 size = len;
554 if (_resolve_debug) {
555#if defined(HAVE_DNS_SEARCH)
556 dns_set_debug(handle, 1);
557#elif defined(HAVE_RES_NSEARCH)
558 state.options |= RES_DEBUG;
559#endif
560 fprintf(stderr, "dns_lookup(%s, %d, %s), buffer size %d\n", domain,
561 rr_class, rk_dns_type_to_string(rr_type), size);
562 }
563 reply = malloc(size);
564 if (reply == NULL) {
565 resolve_free_handle(handle);
566 return NULL;
567 }
568
569 len = resolve_search(handle, domain, rr_class, rr_type, reply, size);
570
571 if (_resolve_debug) {
572 fprintf(stderr, "dns_lookup(%s, %d, %s) --> %d\n",
573 domain, rr_class, rk_dns_type_to_string(rr_type), len);
574 }
575 if (len <= 0) {
576 resolve_free_handle(handle);
577 free(reply);
578 return NULL;
579 }
580 } while (size < len && len < rk_DNS_MAX_PACKET_SIZE);
581 resolve_free_handle(handle);
582
583 len = min(len, size);
584 r = parse_reply(reply, len);
585 free(reply);
586 return r;
587}
588
589struct rk_dns_reply * ROKEN_LIB_FUNCTION
590rk_dns_lookup(const char *domain, const char *type_name)
591{
592 int type;
593
594 type = rk_dns_string_to_type(type_name);
595 if(type == -1) {
596 if(_resolve_debug)
597 fprintf(stderr, "dns_lookup: unknown resource type: `%s'\n",
598 type_name);
599 return NULL;
600 }
601 return dns_lookup_int(domain, rk_ns_c_in, type);
602}
603
604static int
605compare_srv(const void *a, const void *b)
606{
607 const struct rk_resource_record *const* aa = a, *const* bb = b;
608
609 if((*aa)->u.srv->priority == (*bb)->u.srv->priority)
610 return ((*aa)->u.srv->weight - (*bb)->u.srv->weight);
611 return ((*aa)->u.srv->priority - (*bb)->u.srv->priority);
612}
613
614#ifndef HAVE_RANDOM
615#define random() rand()
616#endif
617
618/* try to rearrange the srv-records by the algorithm in RFC2782 */
619void ROKEN_LIB_FUNCTION
620rk_dns_srv_order(struct rk_dns_reply *r)
621{
622 struct rk_resource_record **srvs, **ss, **headp;
623 struct rk_resource_record *rr;
624 int num_srv = 0;
625
626#if defined(HAVE_INITSTATE) && defined(HAVE_SETSTATE)
627 int state[256 / sizeof(int)];
628 char *oldstate;
629#endif
630
631 for(rr = r->head; rr; rr = rr->next)
632 if(rr->type == rk_ns_t_srv)
633 num_srv++;
634
635 if(num_srv == 0)
636 return;
637
638 srvs = malloc(num_srv * sizeof(*srvs));
639 if(srvs == NULL)
640 return; /* XXX not much to do here */
641
642 /* unlink all srv-records from the linked list and put them in
643 a vector */
644 for(ss = srvs, headp = &r->head; *headp; )
645 if((*headp)->type == rk_ns_t_srv) {
646 *ss = *headp;
647 *headp = (*headp)->next;
648 (*ss)->next = NULL;
649 ss++;
650 } else
651 headp = &(*headp)->next;
652
653 /* sort them by priority and weight */
654 qsort(srvs, num_srv, sizeof(*srvs), compare_srv);
655
656#if defined(HAVE_INITSTATE) && defined(HAVE_SETSTATE)
657 oldstate = initstate(time(NULL), (char*)state, sizeof(state));
658#endif
659
660 headp = &r->head;
661
662 for(ss = srvs; ss < srvs + num_srv; ) {
663 int sum, rnd, count;
664 struct rk_resource_record **ee, **tt;
665 /* find the last record with the same priority and count the
666 sum of all weights */
667 for(sum = 0, tt = ss; tt < srvs + num_srv; tt++) {
668 assert(*tt != NULL);
669 if((*tt)->u.srv->priority != (*ss)->u.srv->priority)
670 break;
671 sum += (*tt)->u.srv->weight;
672 }
673 ee = tt;
674 /* ss is now the first record of this priority and ee is the
675 first of the next */
676 while(ss < ee) {
677 rnd = random() % (sum + 1);
678 for(count = 0, tt = ss; ; tt++) {
679 if(*tt == NULL)
680 continue;
681 count += (*tt)->u.srv->weight;
682 if(count >= rnd)
683 break;
684 }
685
686 assert(tt < ee);
687
688 /* insert the selected record at the tail (of the head) of
689 the list */
690 (*tt)->next = *headp;
691 *headp = *tt;
692 headp = &(*tt)->next;
693 sum -= (*tt)->u.srv->weight;
694 *tt = NULL;
695 while(ss < ee && *ss == NULL)
696 ss++;
697 }
698 }
699
700#if defined(HAVE_INITSTATE) && defined(HAVE_SETSTATE)
701 setstate(oldstate);
702#endif
703 free(srvs);
704 return;
705}
706
707#else /* NOT defined(HAVE_RES_SEARCH) && defined(HAVE_DN_EXPAND) */
708
709struct rk_dns_reply * ROKEN_LIB_FUNCTION
710rk_dns_lookup(const char *domain, const char *type_name)
711{
712 return NULL;
713}
714
715void ROKEN_LIB_FUNCTION
716rk_dns_free_data(struct rk_dns_reply *r)
717{
718}
719
720void ROKEN_LIB_FUNCTION
721rk_dns_srv_order(struct rk_dns_reply *r)
722{
723}
724
725#endif
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