xref: /freebsd/crypto/heimdal/lib/roken/resolve.c (revision e0c4386e7e71d93b0edc0c8fa156263fc4a8b0b6)
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 
51 #ifdef _AIX /* AIX have broken res_nsearch() in 5.1 (5.0 also ?) */
52 #undef HAVE_RES_NSEARCH
53 #endif
54 
55 #define DECL(X) {#X, rk_ns_t_##X}
56 
57 static struct stot{
58     const char *name;
59     int type;
60 }stot[] = {
61     DECL(a),
62     DECL(aaaa),
63     DECL(ns),
64     DECL(cname),
65     DECL(soa),
66     DECL(ptr),
67     DECL(mx),
68     DECL(txt),
69     DECL(afsdb),
70     DECL(sig),
71     DECL(key),
72     DECL(srv),
73     DECL(naptr),
74     DECL(sshfp),
75     DECL(ds),
76     {NULL, 	0}
77 };
78 
79 int _resolve_debug = 0;
80 
81 ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
82 rk_dns_string_to_type(const char *name)
83 {
84     struct stot *p = stot;
85     for(p = stot; p->name; p++)
86 	if(strcasecmp(name, p->name) == 0)
87 	    return p->type;
88     return -1;
89 }
90 
91 ROKEN_LIB_FUNCTION const char * ROKEN_LIB_CALL
92 rk_dns_type_to_string(int type)
93 {
94     struct stot *p = stot;
95     for(p = stot; p->name; p++)
96 	if(type == p->type)
97 	    return p->name;
98     return NULL;
99 }
100 
101 #if ((defined(HAVE_RES_SEARCH) || defined(HAVE_RES_NSEARCH)) && defined(HAVE_DN_EXPAND)) || defined(HAVE_WINDNS)
102 
103 static void
104 dns_free_rr(struct rk_resource_record *rr)
105 {
106     if(rr->domain)
107 	free(rr->domain);
108     if(rr->u.data)
109 	free(rr->u.data);
110     free(rr);
111 }
112 
113 ROKEN_LIB_FUNCTION void ROKEN_LIB_CALL
114 rk_dns_free_data(struct rk_dns_reply *r)
115 {
116     struct rk_resource_record *rr;
117     if(r->q.domain)
118 	free(r->q.domain);
119     for(rr = r->head; rr;){
120 	struct rk_resource_record *tmp = rr;
121 	rr = rr->next;
122 	dns_free_rr(tmp);
123     }
124     free (r);
125 }
126 
127 #ifndef HAVE_WINDNS
128 
129 static int
130 parse_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 ((size_t)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 ((size_t)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 < (unsigned)(*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 ((size_t)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
405 static
406 #endif
407 struct rk_dns_reply*
408 parse_reply(const unsigned char *data, size_t len)
409 {
410     const unsigned char *p;
411     int status;
412     size_t 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 
521 static struct rk_dns_reply *
522 dns_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, len;
527 #if defined(HAVE_DNS_SEARCH)
528     struct sockaddr_storage from;
529     uint32_t fromsize = sizeof(from);
530     dns_handle_t handle;
531 
532     handle = dns_open(NULL);
533     if (handle == NULL)
534 	return NULL;
535 #elif defined(HAVE_RES_NSEARCH)
536     struct __res_state state;
537     struct __res_state *handle = &state;
538 
539     memset(&state, 0, sizeof(state));
540     if(res_ninit(handle))
541 	return NULL; /* is this the best we can do? */
542 #endif
543 
544     len = 1500;
545     while(1) {
546 	if (reply) {
547 	    free(reply);
548 	    reply = NULL;
549 	}
550 	if (_resolve_debug) {
551 #if defined(HAVE_DNS_SEARCH)
552 	    dns_set_debug(handle, 1);
553 #elif defined(HAVE_RES_NSEARCH)
554 	    state.options |= RES_DEBUG;
555 #endif
556 	    fprintf(stderr, "dns_lookup(%s, %d, %s), buffer size %d\n", domain,
557 		    rr_class, rk_dns_type_to_string(rr_type), len);
558 	}
559 	reply = malloc(len);
560 	if (reply == NULL) {
561 	    resolve_free_handle(handle);
562 	    return NULL;
563 	}
564 
565 	size = resolve_search(handle, domain, rr_class, rr_type, reply, len);
566 
567 	if (_resolve_debug) {
568 	    fprintf(stderr, "dns_lookup(%s, %d, %s) --> %d\n",
569 		    domain, rr_class, rk_dns_type_to_string(rr_type), size);
570 	}
571 	if (size > len) {
572 	    /* resolver thinks it know better, go for it */
573 	    len = size;
574 	} else if (size > 0) {
575 	    /* got a good reply */
576 	    break;
577 	} else if (size <= 0 && len < rk_DNS_MAX_PACKET_SIZE) {
578 	    len *= 2;
579 	    if (len > rk_DNS_MAX_PACKET_SIZE)
580 		len = rk_DNS_MAX_PACKET_SIZE;
581 	} else {
582 	    /* the end, leave */
583 	    resolve_free_handle(handle);
584 	    free(reply);
585 	    return NULL;
586 	}
587     }
588 
589     len = min(len, size);
590     r = parse_reply(reply, len);
591     free(reply);
592 
593     resolve_free_handle(handle);
594 
595     return r;
596 }
597 
598 ROKEN_LIB_FUNCTION struct rk_dns_reply * ROKEN_LIB_CALL
599 rk_dns_lookup(const char *domain, const char *type_name)
600 {
601     int type;
602 
603     type = rk_dns_string_to_type(type_name);
604     if(type == -1) {
605 	if(_resolve_debug)
606 	    fprintf(stderr, "dns_lookup: unknown resource type: `%s'\n",
607 		    type_name);
608 	return NULL;
609     }
610     return dns_lookup_int(domain, rk_ns_c_in, type);
611 }
612 
613 #endif	/* !HAVE_WINDNS */
614 
615 static int
616 compare_srv(const void *a, const void *b)
617 {
618     const struct rk_resource_record *const* aa = a, *const* bb = b;
619 
620     if((*aa)->u.srv->priority == (*bb)->u.srv->priority)
621 	return ((*aa)->u.srv->weight - (*bb)->u.srv->weight);
622     return ((*aa)->u.srv->priority - (*bb)->u.srv->priority);
623 }
624 
625 /* try to rearrange the srv-records by the algorithm in RFC2782 */
626 ROKEN_LIB_FUNCTION void ROKEN_LIB_CALL
627 rk_dns_srv_order(struct rk_dns_reply *r)
628 {
629     struct rk_resource_record **srvs, **ss, **headp;
630     struct rk_resource_record *rr;
631     int num_srv = 0;
632 
633     rk_random_init();
634 
635     for(rr = r->head; rr; rr = rr->next)
636 	if(rr->type == rk_ns_t_srv)
637 	    num_srv++;
638 
639     if(num_srv == 0)
640 	return;
641 
642     srvs = malloc(num_srv * sizeof(*srvs));
643     if(srvs == NULL)
644 	return; /* XXX not much to do here */
645 
646     /* unlink all srv-records from the linked list and put them in
647        a vector */
648     for(ss = srvs, headp = &r->head; *headp; )
649 	if((*headp)->type == rk_ns_t_srv) {
650 	    *ss = *headp;
651 	    *headp = (*headp)->next;
652 	    (*ss)->next = NULL;
653 	    ss++;
654 	} else
655 	    headp = &(*headp)->next;
656 
657     /* sort them by priority and weight */
658     qsort(srvs, num_srv, sizeof(*srvs), compare_srv);
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 = rk_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     free(srvs);
701     return;
702 }
703 
704 #ifdef HAVE_WINDNS
705 
706 #include <WinDNS.h>
707 
708 static struct rk_resource_record *
709 parse_dns_record(PDNS_RECORD pRec)
710 {
711     struct rk_resource_record * rr;
712 
713     if (pRec == NULL)
714 	return NULL;
715 
716     rr = calloc(1, sizeof(*rr));
717 
718     rr->domain = strdup(pRec->pName);
719     rr->type = pRec->wType;
720     rr->class = 0;
721     rr->ttl = pRec->dwTtl;
722     rr->size = 0;
723 
724     switch (rr->type) {
725     case rk_ns_t_ns:
726     case rk_ns_t_cname:
727     case rk_ns_t_ptr:
728 	rr->u.txt = strdup(pRec->Data.NS.pNameHost);
729 	if(rr->u.txt == NULL) {
730 	    dns_free_rr(rr);
731 	    return NULL;
732 	}
733 	break;
734 
735     case rk_ns_t_mx:
736     case rk_ns_t_afsdb:{
737 	size_t hostlen = strnlen(pRec->Data.MX.pNameExchange, DNS_MAX_NAME_LENGTH);
738 
739 	rr->u.mx = (struct mx_record *)malloc(sizeof(struct mx_record) +
740 					      hostlen);
741 	if (rr->u.mx == NULL) {
742 	    dns_free_rr(rr);
743 	    return NULL;
744 	}
745 
746 	strcpy_s(rr->u.mx->domain, hostlen + 1, pRec->Data.MX.pNameExchange);
747 	rr->u.mx->preference = pRec->Data.MX.wPreference;
748 	break;
749     }
750 
751     case rk_ns_t_srv:{
752 	size_t hostlen = strnlen(pRec->Data.SRV.pNameTarget, DNS_MAX_NAME_LENGTH);
753 
754 	rr->u.srv =
755 	    (struct srv_record*)malloc(sizeof(struct srv_record) +
756 				       hostlen);
757 	if(rr->u.srv == NULL) {
758 	    dns_free_rr(rr);
759 	    return NULL;
760 	}
761 
762 	rr->u.srv->priority = pRec->Data.SRV.wPriority;
763 	rr->u.srv->weight = pRec->Data.SRV.wWeight;
764 	rr->u.srv->port = pRec->Data.SRV.wPort;
765 	strcpy_s(rr->u.srv->target, hostlen + 1, pRec->Data.SRV.pNameTarget);
766 
767 	break;
768     }
769 
770     case rk_ns_t_txt:{
771 	size_t len;
772 
773 	if (pRec->Data.TXT.dwStringCount == 0) {
774 	    rr->u.txt = strdup("");
775 	    break;
776 	}
777 
778 	len = strnlen(pRec->Data.TXT.pStringArray[0], DNS_MAX_TEXT_STRING_LENGTH);
779 
780 	rr->u.txt = (char *)malloc(len + 1);
781 	strcpy_s(rr->u.txt, len + 1, pRec->Data.TXT.pStringArray[0]);
782 
783 	break;
784     }
785 
786     case rk_ns_t_key : {
787 	size_t key_len;
788 
789 	if (pRec->wDataLength < 4) {
790 	    dns_free_rr(rr);
791 	    return NULL;
792 	}
793 
794 	key_len = pRec->wDataLength - 4;
795 	rr->u.key = malloc (sizeof(*rr->u.key) + key_len - 1);
796 	if (rr->u.key == NULL) {
797 	    dns_free_rr(rr);
798 	    return NULL;
799 	}
800 
801 	rr->u.key->flags     = pRec->Data.KEY.wFlags;
802 	rr->u.key->protocol  = pRec->Data.KEY.chProtocol;
803 	rr->u.key->algorithm = pRec->Data.KEY.chAlgorithm;
804 	rr->u.key->key_len   = key_len;
805 	memcpy_s (rr->u.key->key_data, key_len,
806 		  pRec->Data.KEY.Key, key_len);
807 	break;
808     }
809 
810     case rk_ns_t_sig : {
811 	size_t sig_len, hostlen;
812 
813 	if(pRec->wDataLength <= 18) {
814 	    dns_free_rr(rr);
815 	    return NULL;
816 	}
817 
818 	sig_len = pRec->wDataLength;
819 
820 	hostlen = strnlen(pRec->Data.SIG.pNameSigner, DNS_MAX_NAME_LENGTH);
821 
822 	rr->u.sig = malloc(sizeof(*rr->u.sig)
823 			      + hostlen + sig_len);
824 	if (rr->u.sig == NULL) {
825 	    dns_free_rr(rr);
826 	    return NULL;
827 	}
828 	rr->u.sig->type           = pRec->Data.SIG.wTypeCovered;
829 	rr->u.sig->algorithm      = pRec->Data.SIG.chAlgorithm;
830 	rr->u.sig->labels         = pRec->Data.SIG.chLabelCount;
831 	rr->u.sig->orig_ttl       = pRec->Data.SIG.dwOriginalTtl;
832 	rr->u.sig->sig_expiration = pRec->Data.SIG.dwExpiration;
833 	rr->u.sig->sig_inception  = pRec->Data.SIG.dwTimeSigned;
834 	rr->u.sig->key_tag        = pRec->Data.SIG.wKeyTag;
835 	rr->u.sig->sig_len        = sig_len;
836 	memcpy_s (rr->u.sig->sig_data, sig_len,
837 		  pRec->Data.SIG.Signature, sig_len);
838 	rr->u.sig->signer         = &rr->u.sig->sig_data[sig_len];
839 	strcpy_s(rr->u.sig->signer, hostlen + 1, pRec->Data.SIG.pNameSigner);
840 	break;
841     }
842 
843 #ifdef DNS_TYPE_DS
844     case rk_ns_t_ds: {
845 	rr->u.ds = malloc (sizeof(*rr->u.ds) + pRec->Data.DS.wDigestLength - 1);
846 	if (rr->u.ds == NULL) {
847 	    dns_free_rr(rr);
848 	    return NULL;
849 	}
850 
851 	rr->u.ds->key_tag     = pRec->Data.DS.wKeyTag;
852 	rr->u.ds->algorithm   = pRec->Data.DS.chAlgorithm;
853 	rr->u.ds->digest_type = pRec->Data.DS.chDigestType;
854 	rr->u.ds->digest_len  = pRec->Data.DS.wDigestLength;
855 	memcpy_s (rr->u.ds->digest_data, pRec->Data.DS.wDigestLength,
856 		  pRec->Data.DS.Digest, pRec->Data.DS.wDigestLength);
857 	break;
858     }
859 #endif
860 
861     default:
862 	dns_free_rr(rr);
863 	return NULL;
864     }
865 
866     rr->next = parse_dns_record(pRec->pNext);
867     return rr;
868 }
869 
870 ROKEN_LIB_FUNCTION struct rk_dns_reply * ROKEN_LIB_CALL
871 rk_dns_lookup(const char *domain, const char *type_name)
872 {
873     DNS_STATUS status;
874     int type;
875     PDNS_RECORD pRec = NULL;
876     struct rk_dns_reply * r = NULL;
877 
878     __try {
879 
880 	type = rk_dns_string_to_type(type_name);
881 	if(type == -1) {
882 	    if(_resolve_debug)
883 		fprintf(stderr, "dns_lookup: unknown resource type: `%s'\n",
884 			type_name);
885 	    return NULL;
886 	}
887 
888 	status = DnsQuery_UTF8(domain, type, DNS_QUERY_STANDARD, NULL,
889 			       &pRec, NULL);
890 	if (status != ERROR_SUCCESS)
891 	    return NULL;
892 
893 	r = calloc(1, sizeof(*r));
894 	r->q.domain = strdup(domain);
895 	r->q.type = type;
896 	r->q.class = 0;
897 
898 	r->head = parse_dns_record(pRec);
899 
900 	if (r->head == NULL) {
901 	    rk_dns_free_data(r);
902 	    return NULL;
903 	} else {
904 	    return r;
905 	}
906 
907     } __finally {
908 
909 	if (pRec)
910 	    DnsRecordListFree(pRec, DnsFreeRecordList);
911 
912     }
913 }
914 #endif	/* HAVE_WINDNS */
915 
916 #else /* NOT defined(HAVE_RES_SEARCH) && defined(HAVE_DN_EXPAND) */
917 
918 ROKEN_LIB_FUNCTION struct rk_dns_reply * ROKEN_LIB_CALL
919 rk_dns_lookup(const char *domain, const char *type_name)
920 {
921     return NULL;
922 }
923 
924 ROKEN_LIB_FUNCTION void ROKEN_LIB_CALL
925 rk_dns_free_data(struct rk_dns_reply *r)
926 {
927 }
928 
929 ROKEN_LIB_FUNCTION void ROKEN_LIB_CALL
930 rk_dns_srv_order(struct rk_dns_reply *r)
931 {
932 }
933 
934 #endif
935