2 * Copyright (c) 1995 - 2003 Kungliga Tekniska Högskolan
3 * (Royal Institute of Technology, Stockholm, Sweden).
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7 * modification, are permitted provided that the following conditions
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11 * notice, this list of conditions and the following disclaimer.
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18 * may be used to endorse or promote products derived from this software
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38 #ifdef HAVE_ARPA_NAMESER_H
39 #include <arpa/nameser.h>
48 RCSID("$Id: resolve.c,v 1.38.2.1 2003/04/22 15:02:47 lha Exp $");
50 #undef HAVE_RES_NSEARCH
51 #if (defined(HAVE_RES_SEARCH) || defined(HAVE_RES_NSEARCH)) && defined(HAVE_DN_EXPAND)
53 #define DECL(X) {#X, T_##X}
74 int _resolve_debug = 0;
77 dns_string_to_type(const char *name)
79 struct stot *p = stot;
80 for(p = stot; p->name; p++)
81 if(strcasecmp(name, p->name) == 0)
87 dns_type_to_string(int type)
89 struct stot *p = stot;
90 for(p = stot; p->name; p++)
97 dns_free_data(struct dns_reply *r)
99 struct resource_record *rr;
102 for(rr = r->head; rr;){
103 struct resource_record *tmp = rr;
115 parse_record(const unsigned char *data, const unsigned char *end_data,
116 const unsigned char **pp, struct resource_record **rr)
118 int type, class, ttl, size;
121 const unsigned char *p = *pp;
122 status = dn_expand(data, end_data, p, host, sizeof(host));
125 if (p + status + 10 > end_data)
128 type = (p[0] << 8) | p[1];
130 class = (p[0] << 8) | p[1];
132 ttl = (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3];
134 size = (p[0] << 8) | p[1];
137 if (p + size > end_data)
140 *rr = calloc(1, sizeof(**rr));
143 (*rr)->domain = strdup(host);
144 if((*rr)->domain == NULL) {
149 (*rr)->class = class;
156 status = dn_expand(data, end_data, p, host, sizeof(host));
161 (*rr)->u.txt = strdup(host);
162 if((*rr)->u.txt == NULL) {
171 status = dn_expand(data, end_data, p + 2, host, sizeof(host));
176 if (status + 2 > size) {
181 hostlen = strlen(host);
182 (*rr)->u.mx = (struct mx_record*)malloc(sizeof(struct mx_record) +
184 if((*rr)->u.mx == NULL) {
188 (*rr)->u.mx->preference = (p[0] << 8) | p[1];
189 strlcpy((*rr)->u.mx->domain, host, hostlen + 1);
194 status = dn_expand(data, end_data, p + 6, host, sizeof(host));
199 if (status + 6 > size) {
204 hostlen = strlen(host);
206 (struct srv_record*)malloc(sizeof(struct srv_record) +
208 if((*rr)->u.srv == NULL) {
212 (*rr)->u.srv->priority = (p[0] << 8) | p[1];
213 (*rr)->u.srv->weight = (p[2] << 8) | p[3];
214 (*rr)->u.srv->port = (p[4] << 8) | p[5];
215 strlcpy((*rr)->u.srv->target, host, hostlen + 1);
219 if(size == 0 || size < *p + 1) {
223 (*rr)->u.txt = (char*)malloc(*p + 1);
224 if((*rr)->u.txt == NULL) {
228 strncpy((*rr)->u.txt, (char*)p + 1, *p);
229 (*rr)->u.txt[*p] = '\0';
241 (*rr)->u.key = malloc (sizeof(*(*rr)->u.key) + key_len - 1);
242 if ((*rr)->u.key == NULL) {
247 (*rr)->u.key->flags = (p[0] << 8) | p[1];
248 (*rr)->u.key->protocol = p[2];
249 (*rr)->u.key->algorithm = p[3];
250 (*rr)->u.key->key_len = key_len;
251 memcpy ((*rr)->u.key->key_data, p + 4, key_len);
255 size_t sig_len, hostlen;
261 status = dn_expand (data, end_data, p + 18, host, sizeof(host));
266 if (status + 18 > size) {
271 /* the signer name is placed after the sig_data, to make it
272 easy to free this struture; the size calculation below
273 includes the zero-termination if the structure itself.
274 don't you just love C?
276 sig_len = size - 18 - status;
277 hostlen = strlen(host);
278 (*rr)->u.sig = malloc(sizeof(*(*rr)->u.sig)
279 + hostlen + sig_len);
280 if ((*rr)->u.sig == NULL) {
284 (*rr)->u.sig->type = (p[0] << 8) | p[1];
285 (*rr)->u.sig->algorithm = p[2];
286 (*rr)->u.sig->labels = p[3];
287 (*rr)->u.sig->orig_ttl = (p[4] << 24) | (p[5] << 16)
288 | (p[6] << 8) | p[7];
289 (*rr)->u.sig->sig_expiration = (p[8] << 24) | (p[9] << 16)
290 | (p[10] << 8) | p[11];
291 (*rr)->u.sig->sig_inception = (p[12] << 24) | (p[13] << 16)
292 | (p[14] << 8) | p[15];
293 (*rr)->u.sig->key_tag = (p[16] << 8) | p[17];
294 (*rr)->u.sig->sig_len = sig_len;
295 memcpy ((*rr)->u.sig->sig_data, p + 18 + status, sig_len);
296 (*rr)->u.sig->signer = &(*rr)->u.sig->sig_data[sig_len];
297 strlcpy((*rr)->u.sig->signer, host, hostlen + 1);
310 (*rr)->u.cert = malloc (sizeof(*(*rr)->u.cert) + cert_len - 1);
311 if ((*rr)->u.cert == NULL) {
316 (*rr)->u.cert->type = (p[0] << 8) | p[1];
317 (*rr)->u.cert->tag = (p[2] << 8) | p[3];
318 (*rr)->u.cert->algorithm = p[4];
319 (*rr)->u.cert->cert_len = cert_len;
320 memcpy ((*rr)->u.cert->cert_data, p + 5, cert_len);
324 (*rr)->u.data = (unsigned char*)malloc(size);
325 if(size != 0 && (*rr)->u.data == NULL) {
329 memcpy((*rr)->u.data, p, size);
339 parse_reply(const unsigned char *data, size_t len)
341 const unsigned char *p;
345 const unsigned char *end_data = data + len;
347 struct resource_record **rr;
349 r = calloc(1, sizeof(*r));
355 /* doesn't work on Crays */
356 memcpy(&r->h, p, sizeof(HEADER));
359 memcpy(&r->h, p, 12); /* XXX this will probably be mostly garbage */
362 if(ntohs(r->h.qdcount) != 1) {
366 status = dn_expand(data, end_data, p, host, sizeof(host));
371 r->q.domain = strdup(host);
372 if(r->q.domain == NULL) {
376 if (p + status + 4 > end_data) {
381 r->q.type = (p[0] << 8 | p[1]);
383 r->q.class = (p[0] << 8 | p[1]);
387 for(i = 0; i < ntohs(r->h.ancount); i++) {
388 if(parse_record(data, end_data, &p, rr) != 0) {
394 for(i = 0; i < ntohs(r->h.nscount); i++) {
395 if(parse_record(data, end_data, &p, rr) != 0) {
401 for(i = 0; i < ntohs(r->h.arcount); i++) {
402 if(parse_record(data, end_data, &p, rr) != 0) {
412 static struct dns_reply *
413 dns_lookup_int(const char *domain, int rr_class, int rr_type)
415 unsigned char reply[1024];
417 #ifdef HAVE_RES_NSEARCH
418 struct __res_state stat;
419 memset(&stat, 0, sizeof(stat));
421 return NULL; /* is this the best we can do? */
422 #elif defined(HAVE__RES)
423 u_long old_options = 0;
426 if (_resolve_debug) {
427 #ifdef HAVE_RES_NSEARCH
428 stat.options |= RES_DEBUG;
429 #elif defined(HAVE__RES)
430 old_options = _res.options;
431 _res.options |= RES_DEBUG;
433 fprintf(stderr, "dns_lookup(%s, %d, %s)\n", domain,
434 rr_class, dns_type_to_string(rr_type));
436 #ifdef HAVE_RES_NSEARCH
437 len = res_nsearch(&stat, domain, rr_class, rr_type, reply, sizeof(reply));
439 len = res_search(domain, rr_class, rr_type, reply, sizeof(reply));
441 if (_resolve_debug) {
442 #if defined(HAVE__RES) && !defined(HAVE_RES_NSEARCH)
443 _res.options = old_options;
445 fprintf(stderr, "dns_lookup(%s, %d, %s) --> %d\n",
446 domain, rr_class, dns_type_to_string(rr_type), len);
448 #ifdef HAVE_RES_NSEARCH
454 len = min(len, sizeof(reply));
455 return parse_reply(reply, len);
460 dns_lookup(const char *domain, const char *type_name)
464 type = dns_string_to_type(type_name);
467 fprintf(stderr, "dns_lookup: unknown resource type: `%s'\n",
471 return dns_lookup_int(domain, C_IN, type);
475 compare_srv(const void *a, const void *b)
477 const struct resource_record *const* aa = a, *const* bb = b;
479 if((*aa)->u.srv->priority == (*bb)->u.srv->priority)
480 return ((*aa)->u.srv->weight - (*bb)->u.srv->weight);
481 return ((*aa)->u.srv->priority - (*bb)->u.srv->priority);
485 #define random() rand()
488 /* try to rearrange the srv-records by the algorithm in RFC2782 */
490 dns_srv_order(struct dns_reply *r)
492 struct resource_record **srvs, **ss, **headp;
493 struct resource_record *rr;
496 #if defined(HAVE_INITSTATE) && defined(HAVE_SETSTATE)
497 int state[256 / sizeof(int)];
501 for(rr = r->head; rr; rr = rr->next)
502 if(rr->type == T_SRV)
508 srvs = malloc(num_srv * sizeof(*srvs));
510 return; /* XXX not much to do here */
512 /* unlink all srv-records from the linked list and put them in
514 for(ss = srvs, headp = &r->head; *headp; )
515 if((*headp)->type == T_SRV) {
517 *headp = (*headp)->next;
521 headp = &(*headp)->next;
523 /* sort them by priority and weight */
524 qsort(srvs, num_srv, sizeof(*srvs), compare_srv);
526 #if defined(HAVE_INITSTATE) && defined(HAVE_SETSTATE)
527 oldstate = initstate(time(NULL), (char*)state, sizeof(state));
532 for(ss = srvs; ss < srvs + num_srv; ) {
534 struct resource_record **ee, **tt;
535 /* find the last record with the same priority and count the
536 sum of all weights */
537 for(sum = 0, tt = ss; tt < srvs + num_srv; tt++) {
540 if((*tt)->u.srv->priority != (*ss)->u.srv->priority)
542 sum += (*tt)->u.srv->weight;
545 /* ss is now the first record of this priority and ee is the
548 rnd = random() % (sum + 1);
549 for(count = 0, tt = ss; ; tt++) {
552 count += (*tt)->u.srv->weight;
559 /* insert the selected record at the tail (of the head) of
561 (*tt)->next = *headp;
563 headp = &(*tt)->next;
564 sum -= (*tt)->u.srv->weight;
566 while(ss < ee && *ss == NULL)
571 #if defined(HAVE_INITSTATE) && defined(HAVE_SETSTATE)
578 #else /* NOT defined(HAVE_RES_SEARCH) && defined(HAVE_DN_EXPAND) */
581 dns_lookup(const char *domain, const char *type_name)
587 dns_free_data(struct dns_reply *r)
592 dns_srv_order(struct dns_reply *r)
600 main(int argc, char **argv)
603 struct resource_record *rr;
604 r = dns_lookup(argv[1], argv[2]);
606 printf("No reply.\n");
609 if(r->q.type == T_SRV)
612 for(rr = r->head; rr;rr=rr->next){
613 printf("%-30s %-5s %-6d ", rr->domain, dns_type_to_string(rr->type), rr->ttl);
618 printf("%s\n", (char*)rr->u.data);
621 printf("%s\n", inet_ntoa(*rr->u.a));
625 printf("%d %s\n", rr->u.mx->preference, rr->u.mx->domain);
629 struct srv_record *srv = rr->u.srv;
630 printf("%d %d %d %s\n", srv->priority, srv->weight,
631 srv->port, srv->target);
635 printf("%s\n", rr->u.txt);
639 struct sig_record *sig = rr->u.sig;
640 const char *type_string = dns_type_to_string (sig->type);
642 printf ("type %u (%s), algorithm %u, labels %u, orig_ttl %u, sig_expiration %u, sig_inception %u, key_tag %u, signer %s\n",
643 sig->type, type_string ? type_string : "",
644 sig->algorithm, sig->labels, sig->orig_ttl,
645 sig->sig_expiration, sig->sig_inception, sig->key_tag,
650 struct key_record *key = rr->u.key;
652 printf ("flags %u, protocol %u, algorithm %u\n",
653 key->flags, key->protocol, key->algorithm);