1 /* 2 * Copyright (c) 2000-2001 Sendmail, Inc. and its suppliers. 3 * All rights reserved. 4 * 5 * By using this file, you agree to the terms and conditions set 6 * forth in the LICENSE file which can be found at the top level of 7 * the sendmail distribution. 8 * 9 */ 10 11 /* 12 * Copyright (c) 1995, 1996, 1997, 1998, 1999 Kungliga Tekniska H�gskolan 13 * (Royal Institute of Technology, Stockholm, Sweden). 14 * All rights reserved. 15 * 16 * Redistribution and use in source and binary forms, with or without 17 * modification, are permitted provided that the following conditions 18 * are met: 19 * 20 * 1. Redistributions of source code must retain the above copyright 21 * notice, this list of conditions and the following disclaimer. 22 * 23 * 2. Redistributions in binary form must reproduce the above copyright 24 * notice, this list of conditions and the following disclaimer in the 25 * documentation and/or other materials provided with the distribution. 26 * 27 * 3. Neither the name of the Institute nor the names of its contributors 28 * may be used to endorse or promote products derived from this software 29 * without specific prior written permission. 30 * 31 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND 32 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 33 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 34 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE 35 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 36 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 37 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 38 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 39 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 40 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 41 * SUCH DAMAGE. 42 */ 43 44 #include <sendmail.h> 45 #if DNSMAP 46 # if NAMED_BIND 47 # include "sm_resolve.h" 48 49 SM_RCSID("$Id: sm_resolve.c,v 8.24 2001/09/11 04:05:16 gshapiro Exp $") 50 51 static struct stot 52 { 53 const char *st_name; 54 int st_type; 55 } stot[] = 56 { 57 # if NETINET 58 { "A", T_A }, 59 # endif /* NETINET */ 60 # if NETINET6 61 { "AAAA", T_AAAA }, 62 # endif /* NETINET6 */ 63 { "NS", T_NS }, 64 { "CNAME", T_CNAME }, 65 { "PTR", T_PTR }, 66 { "MX", T_MX }, 67 { "TXT", T_TXT }, 68 { "AFSDB", T_AFSDB }, 69 { "SRV", T_SRV }, 70 { NULL, 0 } 71 }; 72 73 /* 74 ** DNS_STRING_TO_TYPE -- convert resource record name into type 75 ** 76 ** Parameters: 77 ** name -- name of resource record type 78 ** 79 ** Returns: 80 ** type if succeeded. 81 ** -1 otherwise. 82 */ 83 84 int 85 dns_string_to_type(name) 86 const char *name; 87 { 88 struct stot *p = stot; 89 90 for (p = stot; p->st_name != NULL; p++) 91 if (sm_strcasecmp(name, p->st_name) == 0) 92 return p->st_type; 93 return -1; 94 } 95 96 /* 97 ** DNS_TYPE_TO_STRING -- convert resource record type into name 98 ** 99 ** Parameters: 100 ** type -- resource record type 101 ** 102 ** Returns: 103 ** name if succeeded. 104 ** NULL otherwise. 105 */ 106 107 const char * 108 dns_type_to_string(type) 109 int type; 110 { 111 struct stot *p = stot; 112 113 for (p = stot; p->st_name != NULL; p++) 114 if (type == p->st_type) 115 return p->st_name; 116 return NULL; 117 } 118 119 /* 120 ** DNS_FREE_DATA -- free all components of a DNS_REPLY_T 121 ** 122 ** Parameters: 123 ** r -- pointer to DNS_REPLY_T 124 ** 125 ** Returns: 126 ** none. 127 */ 128 129 void 130 dns_free_data(r) 131 DNS_REPLY_T *r; 132 { 133 RESOURCE_RECORD_T *rr; 134 135 if (r->dns_r_q.dns_q_domain != NULL) 136 sm_free(r->dns_r_q.dns_q_domain); 137 for (rr = r->dns_r_head; rr != NULL; ) 138 { 139 RESOURCE_RECORD_T *tmp = rr; 140 141 if (rr->rr_domain != NULL) 142 sm_free(rr->rr_domain); 143 if (rr->rr_u.rr_data != NULL) 144 sm_free(rr->rr_u.rr_data); 145 rr = rr->rr_next; 146 sm_free(tmp); 147 } 148 sm_free(r); 149 } 150 151 /* 152 ** PARSE_DNS_REPLY -- parse DNS reply data. 153 ** 154 ** Parameters: 155 ** data -- pointer to dns data 156 ** len -- len of data 157 ** 158 ** Returns: 159 ** pointer to DNS_REPLY_T if succeeded. 160 ** NULL otherwise. 161 */ 162 163 static DNS_REPLY_T * 164 parse_dns_reply(data, len) 165 unsigned char *data; 166 int len; 167 { 168 unsigned char *p; 169 int status; 170 size_t l; 171 char host[MAXHOSTNAMELEN]; 172 DNS_REPLY_T *r; 173 RESOURCE_RECORD_T **rr; 174 175 r = (DNS_REPLY_T *) xalloc(sizeof(*r)); 176 memset(r, 0, sizeof(*r)); 177 if (r == NULL) 178 return NULL; 179 180 p = data; 181 182 /* doesn't work on Crays? */ 183 memcpy(&r->dns_r_h, p, sizeof(HEADER)); 184 p += sizeof(HEADER); 185 status = dn_expand(data, data + len, p, host, sizeof host); 186 if (status < 0) 187 { 188 dns_free_data(r); 189 return NULL; 190 } 191 r->dns_r_q.dns_q_domain = sm_strdup(host); 192 if (r->dns_r_q.dns_q_domain == NULL) 193 { 194 dns_free_data(r); 195 return NULL; 196 } 197 p += status; 198 GETSHORT(r->dns_r_q.dns_q_type, p); 199 GETSHORT(r->dns_r_q.dns_q_class, p); 200 rr = &r->dns_r_head; 201 while (p < data + len) 202 { 203 int type, class, ttl, size; 204 205 status = dn_expand(data, data + len, p, host, sizeof host); 206 if (status < 0) 207 { 208 dns_free_data(r); 209 return NULL; 210 } 211 p += status; 212 GETSHORT(type, p); 213 GETSHORT(class, p); 214 GETLONG(ttl, p); 215 GETSHORT(size, p); 216 *rr = (RESOURCE_RECORD_T *) xalloc(sizeof(RESOURCE_RECORD_T)); 217 if (*rr == NULL) 218 { 219 dns_free_data(r); 220 return NULL; 221 } 222 (*rr)->rr_domain = sm_strdup(host); 223 if ((*rr)->rr_domain == NULL) 224 { 225 dns_free_data(r); 226 return NULL; 227 } 228 (*rr)->rr_type = type; 229 (*rr)->rr_class = class; 230 (*rr)->rr_ttl = ttl; 231 (*rr)->rr_size = size; 232 switch (type) 233 { 234 case T_NS: 235 case T_CNAME: 236 case T_PTR: 237 status = dn_expand(data, data + len, p, host, 238 sizeof host); 239 if (status < 0) 240 { 241 dns_free_data(r); 242 return NULL; 243 } 244 (*rr)->rr_u.rr_txt = sm_strdup(host); 245 if ((*rr)->rr_u.rr_txt == NULL) 246 { 247 dns_free_data(r); 248 return NULL; 249 } 250 break; 251 252 case T_MX: 253 case T_AFSDB: 254 status = dn_expand(data, data + len, p + 2, host, 255 sizeof host); 256 if (status < 0) 257 { 258 dns_free_data(r); 259 return NULL; 260 } 261 l = strlen(host) + 1; 262 (*rr)->rr_u.rr_mx = (MX_RECORD_T *) 263 xalloc(sizeof(MX_RECORD_T) + l); 264 if ((*rr)->rr_u.rr_mx == NULL) 265 { 266 dns_free_data(r); 267 return NULL; 268 } 269 (*rr)->rr_u.rr_mx->mx_r_preference = (p[0] << 8) | p[1]; 270 (void) sm_strlcpy((*rr)->rr_u.rr_mx->mx_r_domain, 271 host, l); 272 break; 273 274 case T_SRV: 275 status = dn_expand(data, data + len, p + 6, host, 276 sizeof host); 277 if (status < 0) 278 { 279 dns_free_data(r); 280 return NULL; 281 } 282 l = strlen(host) + 1; 283 (*rr)->rr_u.rr_srv = (SRV_RECORDT_T*) 284 xalloc(sizeof(SRV_RECORDT_T) + l); 285 if ((*rr)->rr_u.rr_srv == NULL) 286 { 287 dns_free_data(r); 288 return NULL; 289 } 290 (*rr)->rr_u.rr_srv->srv_r_priority = (p[0] << 8) | p[1]; 291 (*rr)->rr_u.rr_srv->srv_r_weight = (p[2] << 8) | p[3]; 292 (*rr)->rr_u.rr_srv->srv_r_port = (p[4] << 8) | p[5]; 293 (void) sm_strlcpy((*rr)->rr_u.rr_srv->srv_r_target, 294 host, l); 295 break; 296 297 case T_TXT: 298 (*rr)->rr_u.rr_txt = (char *) xalloc(size + 1); 299 if ((*rr)->rr_u.rr_txt == NULL) 300 { 301 dns_free_data(r); 302 return NULL; 303 } 304 (void) strncpy((*rr)->rr_u.rr_txt, (char*) p + 1, *p); 305 (*rr)->rr_u.rr_txt[*p] = 0; 306 break; 307 308 default: 309 (*rr)->rr_u.rr_data = (unsigned char*) xalloc(size); 310 if (size != 0 && (*rr)->rr_u.rr_data == NULL) 311 { 312 dns_free_data(r); 313 return NULL; 314 } 315 (void) memcpy((*rr)->rr_u.rr_data, p, size); 316 } 317 p += size; 318 rr = &(*rr)->rr_next; 319 } 320 *rr = NULL; 321 return r; 322 } 323 324 /* 325 ** DNS_LOOKUP_INT -- perform dns map lookup (internal helper routine) 326 ** 327 ** Parameters: 328 ** domain -- name to lookup 329 ** rr_class -- resource record class 330 ** rr_type -- resource record type 331 ** retrans -- retransmission timeout 332 ** retry -- number of retries 333 ** 334 ** Returns: 335 ** result of lookup if succeeded. 336 ** NULL otherwise. 337 */ 338 339 DNS_REPLY_T * 340 dns_lookup_int(domain, rr_class, rr_type, retrans, retry) 341 const char *domain; 342 int rr_class; 343 int rr_type; 344 time_t retrans; 345 int retry; 346 { 347 int len; 348 unsigned long old_options = 0; 349 time_t save_retrans = 0; 350 int save_retry = 0; 351 DNS_REPLY_T *r = NULL; 352 unsigned char reply[1024]; 353 354 if (tTd(8, 16)) 355 { 356 old_options = _res.options; 357 _res.options |= RES_DEBUG; 358 sm_dprintf("dns_lookup(%s, %d, %s)\n", domain, 359 rr_class, dns_type_to_string(rr_type)); 360 } 361 if (retrans > 0) 362 { 363 save_retrans = _res.retrans; 364 _res.retrans = retrans; 365 } 366 if (retry > 0) 367 { 368 save_retry = _res.retry; 369 _res.retry = retry; 370 } 371 errno = 0; 372 SM_SET_H_ERRNO(0); 373 len = res_search(domain, rr_class, rr_type, reply, sizeof reply); 374 if (tTd(8, 16)) 375 { 376 _res.options = old_options; 377 sm_dprintf("dns_lookup(%s, %d, %s) --> %d\n", 378 domain, rr_class, dns_type_to_string(rr_type), len); 379 } 380 if (len >= 0) 381 r = parse_dns_reply(reply, len); 382 if (retrans > 0) 383 _res.retrans = save_retrans; 384 if (retry > 0) 385 _res.retry = save_retry; 386 return r; 387 } 388 389 # if 0 390 DNS_REPLY_T * 391 dns_lookup(domain, type_name, retrans, retry) 392 const char *domain; 393 const char *type_name; 394 time_t retrans; 395 int retry; 396 { 397 int type; 398 399 type = dns_string_to_type(type_name); 400 if (type == -1) 401 { 402 if (tTd(8, 16)) 403 sm_dprintf("dns_lookup: unknown resource type: `%s'\n", 404 type_name); 405 return NULL; 406 } 407 return dns_lookup_int(domain, C_IN, type, retrans, retry); 408 } 409 # endif /* 0 */ 410 # endif /* NAMED_BIND */ 411 #endif /* DNSMAP */ 412