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47 # include "sm_resolve.h"
49 SM_RCSID("$Id: sm_resolve.c,v 8.33 2004/08/04 21:17:57 ca Exp $")
62 # endif /* NETINET6 */
73 static DNS_REPLY_T *parse_dns_reply __P((unsigned char *, int));
76 ** DNS_STRING_TO_TYPE -- convert resource record name into type
79 ** name -- name of resource record type
87 dns_string_to_type(name)
90 struct stot *p = stot;
92 for (p = stot; p->st_name != NULL; p++)
93 if (sm_strcasecmp(name, p->st_name) == 0)
99 ** DNS_TYPE_TO_STRING -- convert resource record type into name
102 ** type -- resource record type
105 ** name if succeeded.
110 dns_type_to_string(type)
113 struct stot *p = stot;
115 for (p = stot; p->st_name != NULL; p++)
116 if (type == p->st_type)
122 ** DNS_FREE_DATA -- free all components of a DNS_REPLY_T
125 ** r -- pointer to DNS_REPLY_T
135 RESOURCE_RECORD_T *rr;
137 if (r->dns_r_q.dns_q_domain != NULL)
138 sm_free(r->dns_r_q.dns_q_domain);
139 for (rr = r->dns_r_head; rr != NULL; )
141 RESOURCE_RECORD_T *tmp = rr;
143 if (rr->rr_domain != NULL)
144 sm_free(rr->rr_domain);
145 if (rr->rr_u.rr_data != NULL)
146 sm_free(rr->rr_u.rr_data);
154 ** PARSE_DNS_REPLY -- parse DNS reply data.
157 ** data -- pointer to dns data
158 ** len -- len of data
161 ** pointer to DNS_REPLY_T if succeeded.
166 parse_dns_reply(data, len)
173 char host[MAXHOSTNAMELEN];
175 RESOURCE_RECORD_T **rr;
177 r = (DNS_REPLY_T *) sm_malloc(sizeof(*r));
180 memset(r, 0, sizeof(*r));
184 /* doesn't work on Crays? */
185 memcpy(&r->dns_r_h, p, sizeof(r->dns_r_h));
186 p += sizeof(r->dns_r_h);
187 status = dn_expand(data, data + len, p, host, sizeof host);
193 r->dns_r_q.dns_q_domain = sm_strdup(host);
194 if (r->dns_r_q.dns_q_domain == NULL)
200 GETSHORT(r->dns_r_q.dns_q_type, p);
201 GETSHORT(r->dns_r_q.dns_q_class, p);
203 while (p < data + len)
205 int type, class, ttl, size, txtlen;
207 status = dn_expand(data, data + len, p, host, sizeof host);
218 if (p + size > data + len)
221 ** announced size of data exceeds length of
222 ** data paket: someone is cheating.
226 sm_syslog(LOG_WARNING, NOQID,
227 "ERROR: DNS RDLENGTH=%d > data len=%d",
228 size, len - (p - data));
232 *rr = (RESOURCE_RECORD_T *) sm_malloc(sizeof(**rr));
238 memset(*rr, 0, sizeof(**rr));
239 (*rr)->rr_domain = sm_strdup(host);
240 if ((*rr)->rr_domain == NULL)
245 (*rr)->rr_type = type;
246 (*rr)->rr_class = class;
248 (*rr)->rr_size = size;
254 status = dn_expand(data, data + len, p, host,
261 (*rr)->rr_u.rr_txt = sm_strdup(host);
262 if ((*rr)->rr_u.rr_txt == NULL)
271 status = dn_expand(data, data + len, p + 2, host,
278 l = strlen(host) + 1;
279 (*rr)->rr_u.rr_mx = (MX_RECORD_T *)
280 sm_malloc(sizeof(*((*rr)->rr_u.rr_mx)) + l);
281 if ((*rr)->rr_u.rr_mx == NULL)
286 (*rr)->rr_u.rr_mx->mx_r_preference = (p[0] << 8) | p[1];
287 (void) sm_strlcpy((*rr)->rr_u.rr_mx->mx_r_domain,
292 status = dn_expand(data, data + len, p + 6, host,
299 l = strlen(host) + 1;
300 (*rr)->rr_u.rr_srv = (SRV_RECORDT_T*)
301 sm_malloc(sizeof(*((*rr)->rr_u.rr_srv)) + l);
302 if ((*rr)->rr_u.rr_srv == NULL)
307 (*rr)->rr_u.rr_srv->srv_r_priority = (p[0] << 8) | p[1];
308 (*rr)->rr_u.rr_srv->srv_r_weight = (p[2] << 8) | p[3];
309 (*rr)->rr_u.rr_srv->srv_r_port = (p[4] << 8) | p[5];
310 (void) sm_strlcpy((*rr)->rr_u.rr_srv->srv_r_target,
317 ** The TXT record contains the length as
318 ** leading byte, hence the value is restricted
319 ** to 255, which is less than the maximum value
320 ** of RDLENGTH (size). Nevertheless, txtlen
321 ** must be less than size because the latter
322 ** specifies the length of the entire TXT
330 sm_syslog(LOG_WARNING, NOQID,
331 "ERROR: DNS TXT record size=%d <= text len=%d",
336 (*rr)->rr_u.rr_txt = (char *) sm_malloc(txtlen + 1);
337 if ((*rr)->rr_u.rr_txt == NULL)
342 (void) sm_strlcpy((*rr)->rr_u.rr_txt, (char*) p + 1,
347 (*rr)->rr_u.rr_data = (unsigned char*) sm_malloc(size);
348 if ((*rr)->rr_u.rr_data == NULL)
353 (void) memcpy((*rr)->rr_u.rr_data, p, size);
357 rr = &(*rr)->rr_next;
364 ** DNS_LOOKUP_INT -- perform dns map lookup (internal helper routine)
367 ** domain -- name to lookup
368 ** rr_class -- resource record class
369 ** rr_type -- resource record type
370 ** retrans -- retransmission timeout
371 ** retry -- number of retries
374 ** result of lookup if succeeded.
379 dns_lookup_int(domain, rr_class, rr_type, retrans, retry)
387 unsigned long old_options = 0;
388 time_t save_retrans = 0;
390 DNS_REPLY_T *r = NULL;
391 unsigned char reply[1024];
395 old_options = _res.options;
396 _res.options |= RES_DEBUG;
397 sm_dprintf("dns_lookup(%s, %d, %s)\n", domain,
398 rr_class, dns_type_to_string(rr_type));
402 save_retrans = _res.retrans;
403 _res.retrans = retrans;
407 save_retry = _res.retry;
412 len = res_search(domain, rr_class, rr_type, reply, sizeof reply);
415 _res.options = old_options;
416 sm_dprintf("dns_lookup(%s, %d, %s) --> %d\n",
417 domain, rr_class, dns_type_to_string(rr_type), len);
420 r = parse_dns_reply(reply, len);
422 _res.retrans = save_retrans;
424 _res.retry = save_retry;
430 dns_lookup(domain, type_name, retrans, retry)
432 const char *type_name;
438 type = dns_string_to_type(type_name);
442 sm_dprintf("dns_lookup: unknown resource type: `%s'\n",
446 return dns_lookup_int(domain, C_IN, type, retrans, retry);
449 # endif /* NAMED_BIND */