2 * Copyright (c) 1995 - 2006 Kungliga Tekniska Högskolan
3 * (Royal Institute of Technology, Stockholm, Sweden).
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
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.
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.
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
38 #ifdef HAVE_ARPA_NAMESER_H
39 #include <arpa/nameser.h>
48 RCSID("$Id: resolve.c 19869 2007-01-12 16:03:14Z lha $");
50 #ifdef _AIX /* AIX have broken res_nsearch() in 5.1 (5.0 also ?) */
51 #undef HAVE_RES_NSEARCH
54 #define DECL(X) {#X, rk_ns_t_##X}
78 int _resolve_debug = 0;
80 int ROKEN_LIB_FUNCTION
81 dns_string_to_type(const char *name)
83 struct stot *p = stot;
84 for(p = stot; p->name; p++)
85 if(strcasecmp(name, p->name) == 0)
90 const char * ROKEN_LIB_FUNCTION
91 dns_type_to_string(int type)
93 struct stot *p = stot;
94 for(p = stot; p->name; p++)
100 #if (defined(HAVE_RES_SEARCH) || defined(HAVE_RES_NSEARCH)) && defined(HAVE_DN_EXPAND)
103 dns_free_rr(struct resource_record *rr)
112 void ROKEN_LIB_FUNCTION
113 dns_free_data(struct dns_reply *r)
115 struct resource_record *rr;
118 for(rr = r->head; rr;){
119 struct resource_record *tmp = rr;
127 parse_record(const unsigned char *data, const unsigned char *end_data,
128 const unsigned char **pp, struct resource_record **ret_rr)
130 struct resource_record *rr;
131 int type, class, ttl, size;
134 const unsigned char *p = *pp;
138 status = dn_expand(data, end_data, p, host, sizeof(host));
141 if (p + status + 10 > end_data)
145 type = (p[0] << 8) | p[1];
147 class = (p[0] << 8) | p[1];
149 ttl = (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3];
151 size = (p[0] << 8) | p[1];
154 if (p + size > end_data)
157 rr = calloc(1, sizeof(*rr));
160 rr->domain = strdup(host);
161 if(rr->domain == NULL) {
173 status = dn_expand(data, end_data, p, host, sizeof(host));
178 rr->u.txt = strdup(host);
179 if(rr->u.txt == NULL) {
188 status = dn_expand(data, end_data, p + 2, host, sizeof(host));
193 if (status + 2 > size) {
198 hostlen = strlen(host);
199 rr->u.mx = (struct mx_record*)malloc(sizeof(struct mx_record) +
201 if(rr->u.mx == NULL) {
205 rr->u.mx->preference = (p[0] << 8) | p[1];
206 strlcpy(rr->u.mx->domain, host, hostlen + 1);
211 status = dn_expand(data, end_data, p + 6, host, sizeof(host));
216 if (status + 6 > size) {
221 hostlen = strlen(host);
223 (struct srv_record*)malloc(sizeof(struct srv_record) +
225 if(rr->u.srv == NULL) {
229 rr->u.srv->priority = (p[0] << 8) | p[1];
230 rr->u.srv->weight = (p[2] << 8) | p[3];
231 rr->u.srv->port = (p[4] << 8) | p[5];
232 strlcpy(rr->u.srv->target, host, hostlen + 1);
236 if(size == 0 || size < *p + 1) {
240 rr->u.txt = (char*)malloc(*p + 1);
241 if(rr->u.txt == NULL) {
245 strncpy(rr->u.txt, (const char*)(p + 1), *p);
246 rr->u.txt[*p] = '\0';
258 rr->u.key = malloc (sizeof(*rr->u.key) + key_len - 1);
259 if (rr->u.key == NULL) {
264 rr->u.key->flags = (p[0] << 8) | p[1];
265 rr->u.key->protocol = p[2];
266 rr->u.key->algorithm = p[3];
267 rr->u.key->key_len = key_len;
268 memcpy (rr->u.key->key_data, p + 4, key_len);
272 size_t sig_len, hostlen;
278 status = dn_expand (data, end_data, p + 18, host, sizeof(host));
283 if (status + 18 > size) {
288 /* the signer name is placed after the sig_data, to make it
289 easy to free this structure; the size calculation below
290 includes the zero-termination if the structure itself.
291 don't you just love C?
293 sig_len = size - 18 - status;
294 hostlen = strlen(host);
295 rr->u.sig = malloc(sizeof(*rr->u.sig)
296 + hostlen + sig_len);
297 if (rr->u.sig == NULL) {
301 rr->u.sig->type = (p[0] << 8) | p[1];
302 rr->u.sig->algorithm = p[2];
303 rr->u.sig->labels = p[3];
304 rr->u.sig->orig_ttl = (p[4] << 24) | (p[5] << 16)
305 | (p[6] << 8) | p[7];
306 rr->u.sig->sig_expiration = (p[8] << 24) | (p[9] << 16)
307 | (p[10] << 8) | p[11];
308 rr->u.sig->sig_inception = (p[12] << 24) | (p[13] << 16)
309 | (p[14] << 8) | p[15];
310 rr->u.sig->key_tag = (p[16] << 8) | p[17];
311 rr->u.sig->sig_len = sig_len;
312 memcpy (rr->u.sig->sig_data, p + 18 + status, sig_len);
313 rr->u.sig->signer = &rr->u.sig->sig_data[sig_len];
314 strlcpy(rr->u.sig->signer, host, hostlen + 1);
318 case rk_ns_t_cert : {
327 rr->u.cert = malloc (sizeof(*rr->u.cert) + cert_len - 1);
328 if (rr->u.cert == NULL) {
333 rr->u.cert->type = (p[0] << 8) | p[1];
334 rr->u.cert->tag = (p[2] << 8) | p[3];
335 rr->u.cert->algorithm = p[4];
336 rr->u.cert->cert_len = cert_len;
337 memcpy (rr->u.cert->cert_data, p + 5, cert_len);
340 case rk_ns_t_sshfp : {
348 sshfp_len = size - 2;
350 rr->u.sshfp = malloc (sizeof(*rr->u.sshfp) + sshfp_len - 1);
351 if (rr->u.sshfp == NULL) {
356 rr->u.sshfp->algorithm = p[0];
357 rr->u.sshfp->type = p[1];
358 rr->u.sshfp->sshfp_len = sshfp_len;
359 memcpy (rr->u.sshfp->sshfp_data, p + 2, sshfp_len);
370 digest_len = size - 4;
372 rr->u.ds = malloc (sizeof(*rr->u.ds) + digest_len - 1);
373 if (rr->u.ds == NULL) {
378 rr->u.ds->key_tag = (p[0] << 8) | p[1];
379 rr->u.ds->algorithm = p[2];
380 rr->u.ds->digest_type = p[3];
381 rr->u.ds->digest_len = digest_len;
382 memcpy (rr->u.ds->digest_data, p + 4, digest_len);
386 rr->u.data = (unsigned char*)malloc(size);
387 if(size != 0 && rr->u.data == NULL) {
392 memcpy(rr->u.data, p, size);
404 parse_reply(const unsigned char *data, size_t len)
406 const unsigned char *p;
410 const unsigned char *end_data = data + len;
412 struct resource_record **rr;
414 r = calloc(1, sizeof(*r));
420 r->h.id = (p[0] << 8) | p[1];
423 r->h.flags |= rk_DNS_HEADER_RESPONSE_FLAG;
424 r->h.opcode = (p[2] >> 1) & 0xf;
426 r->h.flags |= rk_DNS_HEADER_AUTHORITIVE_ANSWER;
428 r->h.flags |= rk_DNS_HEADER_TRUNCATED_MESSAGE;
430 r->h.flags |= rk_DNS_HEADER_RECURSION_DESIRED;
432 r->h.flags |= rk_DNS_HEADER_RECURSION_AVAILABLE;
434 r->h.flags |= rk_DNS_HEADER_AUTHORITIVE_ANSWER;
436 r->h.flags |= rk_DNS_HEADER_CHECKING_DISABLED;
437 r->h.response_code = (p[3] >> 4) & 0xf;
438 r->h.qdcount = (p[4] << 8) | p[5];
439 r->h.ancount = (p[6] << 8) | p[7];
440 r->h.nscount = (p[8] << 8) | p[9];
441 r->h.arcount = (p[10] << 8) | p[11];
445 if(r->h.qdcount != 1) {
449 status = dn_expand(data, end_data, p, host, sizeof(host));
454 r->q.domain = strdup(host);
455 if(r->q.domain == NULL) {
459 if (p + status + 4 > end_data) {
464 r->q.type = (p[0] << 8 | p[1]);
466 r->q.class = (p[0] << 8 | p[1]);
470 for(i = 0; i < r->h.ancount; i++) {
471 if(parse_record(data, end_data, &p, rr) != 0) {
477 for(i = 0; i < r->h.nscount; i++) {
478 if(parse_record(data, end_data, &p, rr) != 0) {
484 for(i = 0; i < r->h.arcount; i++) {
485 if(parse_record(data, end_data, &p, rr) != 0) {
495 #ifdef HAVE_RES_NSEARCH
496 #ifdef HAVE_RES_NDESTROY
497 #define rk_res_free(x) res_ndestroy(x)
499 #define rk_res_free(x) res_nclose(x)
503 static struct dns_reply *
504 dns_lookup_int(const char *domain, int rr_class, int rr_type)
507 unsigned char *reply = NULL;
510 #ifdef HAVE_RES_NSEARCH
511 struct __res_state state;
512 memset(&state, 0, sizeof(state));
513 if(res_ninit(&state))
514 return NULL; /* is this the best we can do? */
515 #elif defined(HAVE__RES)
516 u_long old_options = 0;
528 if (_resolve_debug) {
529 #ifdef HAVE_RES_NSEARCH
530 state.options |= RES_DEBUG;
531 #elif defined(HAVE__RES)
532 old_options = _res.options;
533 _res.options |= RES_DEBUG;
535 fprintf(stderr, "dns_lookup(%s, %d, %s), buffer size %d\n", domain,
536 rr_class, dns_type_to_string(rr_type), size);
538 reply = malloc(size);
540 #ifdef HAVE_RES_NSEARCH
545 #ifdef HAVE_RES_NSEARCH
546 len = res_nsearch(&state, domain, rr_class, rr_type, reply, size);
548 len = res_search(domain, rr_class, rr_type, reply, size);
550 if (_resolve_debug) {
551 #if defined(HAVE__RES) && !defined(HAVE_RES_NSEARCH)
552 _res.options = old_options;
554 fprintf(stderr, "dns_lookup(%s, %d, %s) --> %d\n",
555 domain, rr_class, dns_type_to_string(rr_type), len);
558 #ifdef HAVE_RES_NSEARCH
564 } while (size < len && len < rk_DNS_MAX_PACKET_SIZE);
565 #ifdef HAVE_RES_NSEARCH
569 len = min(len, size);
570 r = parse_reply(reply, len);
575 struct dns_reply * ROKEN_LIB_FUNCTION
576 dns_lookup(const char *domain, const char *type_name)
580 type = dns_string_to_type(type_name);
583 fprintf(stderr, "dns_lookup: unknown resource type: `%s'\n",
587 return dns_lookup_int(domain, C_IN, type);
591 compare_srv(const void *a, const void *b)
593 const struct resource_record *const* aa = a, *const* bb = b;
595 if((*aa)->u.srv->priority == (*bb)->u.srv->priority)
596 return ((*aa)->u.srv->weight - (*bb)->u.srv->weight);
597 return ((*aa)->u.srv->priority - (*bb)->u.srv->priority);
601 #define random() rand()
604 /* try to rearrange the srv-records by the algorithm in RFC2782 */
605 void ROKEN_LIB_FUNCTION
606 dns_srv_order(struct dns_reply *r)
608 struct resource_record **srvs, **ss, **headp;
609 struct resource_record *rr;
612 #if defined(HAVE_INITSTATE) && defined(HAVE_SETSTATE)
613 int state[256 / sizeof(int)];
617 for(rr = r->head; rr; rr = rr->next)
618 if(rr->type == rk_ns_t_srv)
624 srvs = malloc(num_srv * sizeof(*srvs));
626 return; /* XXX not much to do here */
628 /* unlink all srv-records from the linked list and put them in
630 for(ss = srvs, headp = &r->head; *headp; )
631 if((*headp)->type == rk_ns_t_srv) {
633 *headp = (*headp)->next;
637 headp = &(*headp)->next;
639 /* sort them by priority and weight */
640 qsort(srvs, num_srv, sizeof(*srvs), compare_srv);
642 #if defined(HAVE_INITSTATE) && defined(HAVE_SETSTATE)
643 oldstate = initstate(time(NULL), (char*)state, sizeof(state));
648 for(ss = srvs; ss < srvs + num_srv; ) {
650 struct resource_record **ee, **tt;
651 /* find the last record with the same priority and count the
652 sum of all weights */
653 for(sum = 0, tt = ss; tt < srvs + num_srv; tt++) {
655 if((*tt)->u.srv->priority != (*ss)->u.srv->priority)
657 sum += (*tt)->u.srv->weight;
660 /* ss is now the first record of this priority and ee is the
663 rnd = random() % (sum + 1);
664 for(count = 0, tt = ss; ; tt++) {
667 count += (*tt)->u.srv->weight;
674 /* insert the selected record at the tail (of the head) of
676 (*tt)->next = *headp;
678 headp = &(*tt)->next;
679 sum -= (*tt)->u.srv->weight;
681 while(ss < ee && *ss == NULL)
686 #if defined(HAVE_INITSTATE) && defined(HAVE_SETSTATE)
693 #else /* NOT defined(HAVE_RES_SEARCH) && defined(HAVE_DN_EXPAND) */
695 struct dns_reply * ROKEN_LIB_FUNCTION
696 dns_lookup(const char *domain, const char *type_name)
701 void ROKEN_LIB_FUNCTION
702 dns_free_data(struct dns_reply *r)
706 void ROKEN_LIB_FUNCTION
707 dns_srv_order(struct dns_reply *r)