1 /*- 2 * Copyright (c) 1985, 1988, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * - 29 * Portions Copyright (c) 1993 by Digital Equipment Corporation. 30 * 31 * Permission to use, copy, modify, and distribute this software for any 32 * purpose with or without fee is hereby granted, provided that the above 33 * copyright notice and this permission notice appear in all copies, and that 34 * the name of Digital Equipment Corporation not be used in advertising or 35 * publicity pertaining to distribution of the document or software without 36 * specific, written prior permission. 37 * 38 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL 39 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES 40 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT 41 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL 42 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR 43 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS 44 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS 45 * SOFTWARE. 46 * - 47 * --Copyright-- 48 */ 49 /* Portions Copyright (c) 1993 Carlos Leandro and Rui Salgueiro 50 * Dep. Matematica Universidade de Coimbra, Portugal, Europe 51 * 52 * Permission to use, copy, modify, and distribute this software for any 53 * purpose with or without fee is hereby granted, provided that the above 54 * copyright notice and this permission notice appear in all copies. 55 */ 56 57 #if defined(LIBC_SCCS) && !defined(lint) 58 static char sccsid[] = "@(#)gethostnamadr.c 8.1 (Berkeley) 6/4/93"; 59 #endif /* LIBC_SCCS and not lint */ 60 #include <sys/cdefs.h> 61 __FBSDID("$FreeBSD$"); 62 63 #include <sys/param.h> 64 #include <sys/socket.h> 65 #include <netinet/in.h> 66 #include <arpa/inet.h> 67 #include <arpa/nameser.h> 68 69 #include <errno.h> 70 #include <stdio.h> 71 #include <stdlib.h> 72 #include <netdb.h> 73 #include <resolv.h> 74 #include <ctype.h> 75 #include <string.h> 76 #include <unistd.h> 77 #include <syslog.h> 78 #include <stdarg.h> 79 #include <nsswitch.h> 80 81 #include "netdb_private.h" 82 #include "res_config.h" 83 84 #define BYADDR 0 85 #define BYNAME 1 86 87 #define MAXPACKET (64*1024) 88 89 typedef union { 90 HEADER hdr; 91 u_char buf[MAXPACKET]; 92 } querybuf; 93 94 typedef union { 95 long al; 96 char ac; 97 } align; 98 99 /* 100 * Reverse the order of first four dotted entries of in. 101 * Out must contain space for at least strlen(in) characters. 102 * The result does not include any leading 0s of in. 103 */ 104 static void 105 ipreverse(char *in, char *out) 106 { 107 char *pos[4]; 108 int len[4]; 109 char *p, *start; 110 int i = 0; 111 int leading = 1; 112 113 /* Fill-in element positions and lengths: pos[], len[]. */ 114 start = p = in; 115 for (;;) { 116 if (*p == '.' || *p == '\0') { 117 /* Leading 0? */ 118 if (leading && p - start == 1 && *start == '0') 119 len[i] = 0; 120 else { 121 len[i] = p - start; 122 leading = 0; 123 } 124 pos[i] = start; 125 start = p + 1; 126 i++; 127 } 128 if (i == 4) 129 break; 130 if (*p == 0) { 131 for (; i < 4; i++) { 132 pos[i] = p; 133 len[i] = 0; 134 } 135 break; 136 } 137 p++; 138 } 139 140 /* Copy the entries in reverse order */ 141 p = out; 142 leading = 1; 143 for (i = 3; i >= 0; i--) { 144 memcpy(p, pos[i], len[i]); 145 if (len[i]) 146 leading = 0; 147 p += len[i]; 148 /* Need a . separator? */ 149 if (!leading && i > 0 && len[i - 1]) 150 *p++ = '.'; 151 } 152 *p = '\0'; 153 } 154 155 static int 156 getnetanswer(querybuf *answer, int anslen, int net_i, struct netent *ne, 157 struct netent_data *ned, res_state statp) 158 { 159 160 HEADER *hp; 161 u_char *cp; 162 int n; 163 u_char *eom; 164 int type, class, ancount, qdcount, haveanswer; 165 char aux[MAXHOSTNAMELEN]; 166 char ans[MAXHOSTNAMELEN]; 167 char *in, *bp, *ep, **ap; 168 169 /* 170 * find first satisfactory answer 171 * 172 * answer --> +------------+ ( MESSAGE ) 173 * | Header | 174 * +------------+ 175 * | Question | the question for the name server 176 * +------------+ 177 * | Answer | RRs answering the question 178 * +------------+ 179 * | Authority | RRs pointing toward an authority 180 * | Additional | RRs holding additional information 181 * +------------+ 182 */ 183 eom = answer->buf + anslen; 184 hp = &answer->hdr; 185 ancount = ntohs(hp->ancount); /* #/records in the answer section */ 186 qdcount = ntohs(hp->qdcount); /* #/entries in the question section */ 187 bp = ned->netbuf; 188 ep = ned->netbuf + sizeof(ned->netbuf); 189 cp = answer->buf + HFIXEDSZ; 190 if (!qdcount) { 191 if (hp->aa) 192 RES_SET_H_ERRNO(statp, HOST_NOT_FOUND); 193 else 194 RES_SET_H_ERRNO(statp, TRY_AGAIN); 195 return (-1); 196 } 197 while (qdcount-- > 0) 198 cp += __dn_skipname(cp, eom) + QFIXEDSZ; 199 ap = ned->net_aliases; 200 *ap = NULL; 201 ne->n_aliases = ned->net_aliases; 202 haveanswer = 0; 203 while (--ancount >= 0 && cp < eom) { 204 n = dn_expand(answer->buf, eom, cp, bp, ep - bp); 205 if ((n < 0) || !res_dnok(bp)) 206 break; 207 cp += n; 208 ans[0] = '\0'; 209 (void)strncpy(&ans[0], bp, sizeof(ans) - 1); 210 ans[sizeof(ans) - 1] = '\0'; 211 GETSHORT(type, cp); 212 GETSHORT(class, cp); 213 cp += INT32SZ; /* TTL */ 214 GETSHORT(n, cp); 215 if (class == C_IN && type == T_PTR) { 216 n = dn_expand(answer->buf, eom, cp, bp, ep - bp); 217 if ((n < 0) || !res_hnok(bp)) { 218 cp += n; 219 return (-1); 220 } 221 cp += n; 222 *ap++ = bp; 223 n = strlen(bp) + 1; 224 bp += n; 225 ne->n_addrtype = (class == C_IN) ? AF_INET : AF_UNSPEC; 226 haveanswer++; 227 } 228 } 229 if (haveanswer) { 230 *ap = NULL; 231 switch (net_i) { 232 case BYADDR: 233 ne->n_name = *ne->n_aliases; 234 ne->n_net = 0L; 235 break; 236 case BYNAME: 237 in = *ne->n_aliases; 238 n = strlen(ans) + 1; 239 if (ep - bp < n) { 240 RES_SET_H_ERRNO(statp, NETDB_INTERNAL); 241 errno = ENOBUFS; 242 return (-1); 243 } 244 strlcpy(bp, ans, ep - bp); 245 ne->n_name = bp; 246 if (strlen(in) + 1 > sizeof(aux)) { 247 RES_SET_H_ERRNO(statp, NETDB_INTERNAL); 248 errno = ENOBUFS; 249 return (-1); 250 } 251 ipreverse(in, aux); 252 ne->n_net = inet_network(aux); 253 break; 254 } 255 ne->n_aliases++; 256 return (0); 257 } 258 RES_SET_H_ERRNO(statp, TRY_AGAIN); 259 return (-1); 260 } 261 262 int 263 _dns_getnetbyaddr(void *rval, void *cb_data, va_list ap) 264 { 265 uint32_t net; 266 int net_type; 267 char *buffer; 268 size_t buflen; 269 int *errnop, *h_errnop; 270 struct netent *nptr, ne; 271 struct netent_data *ned; 272 unsigned int netbr[4]; 273 int nn, anslen, error; 274 querybuf *buf; 275 char qbuf[MAXDNAME]; 276 uint32_t net2; 277 res_state statp; 278 279 net = va_arg(ap, uint32_t); 280 net_type = va_arg(ap, int); 281 nptr = va_arg(ap, struct netent *); 282 buffer = va_arg(ap, char *); 283 buflen = va_arg(ap, size_t); 284 errnop = va_arg(ap, int *); 285 h_errnop = va_arg(ap, int *); 286 287 statp = __res_state(); 288 if ((statp->options & RES_INIT) == 0 && res_ninit(statp) == -1) { 289 RES_SET_H_ERRNO(statp, NETDB_INTERNAL); 290 *h_errnop = statp->res_h_errno; 291 return (NS_UNAVAIL); 292 } 293 294 if ((ned = __netent_data_init()) == NULL) { 295 RES_SET_H_ERRNO(statp, NETDB_INTERNAL); 296 *h_errnop = statp->res_h_errno; 297 return (NS_UNAVAIL); 298 } 299 300 *((struct netent **)rval) = NULL; 301 302 if (net_type != AF_INET) { 303 RES_SET_H_ERRNO(statp, NETDB_INTERNAL); 304 *h_errnop = statp->res_h_errno; 305 return (NS_UNAVAIL); 306 } 307 308 for (nn = 4, net2 = net; net2; net2 >>= 8) 309 netbr[--nn] = net2 & 0xff; 310 switch (nn) { 311 case 3: /* Class A */ 312 sprintf(qbuf, "0.0.0.%u.in-addr.arpa", netbr[3]); 313 break; 314 case 2: /* Class B */ 315 sprintf(qbuf, "0.0.%u.%u.in-addr.arpa", netbr[3], netbr[2]); 316 break; 317 case 1: /* Class C */ 318 sprintf(qbuf, "0.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2], 319 netbr[1]); 320 break; 321 case 0: /* Class D - E */ 322 sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2], 323 netbr[1], netbr[0]); 324 break; 325 } 326 if ((buf = malloc(sizeof(*buf))) == NULL) { 327 RES_SET_H_ERRNO(statp, NETDB_INTERNAL); 328 *h_errnop = statp->res_h_errno; 329 return (NS_NOTFOUND); 330 } 331 anslen = res_nquery(statp, qbuf, C_IN, T_PTR, (u_char *)buf, 332 sizeof(*buf)); 333 if (anslen < 0) { 334 free(buf); 335 #ifdef DEBUG 336 if (statp->options & RES_DEBUG) 337 printf("res_nsearch failed\n"); 338 #endif 339 *h_errnop = statp->res_h_errno; 340 return (NS_UNAVAIL); 341 } else if (anslen > sizeof(*buf)) { 342 free(buf); 343 #ifdef DEBUG 344 if (statp->options & RES_DEBUG) 345 printf("res_nsearch static buffer too small\n"); 346 #endif 347 *h_errnop = statp->res_h_errno; 348 return (NS_UNAVAIL); 349 } 350 error = getnetanswer(buf, anslen, BYADDR, &ne, ned, statp); 351 free(buf); 352 if (error == 0) { 353 /* Strip trailing zeros */ 354 while ((net & 0xff) == 0 && net != 0) 355 net >>= 8; 356 ne.n_net = net; 357 if (__copy_netent(&ne, nptr, buffer, buflen) != 0) { 358 *errnop = errno; 359 RES_SET_H_ERRNO(statp, NETDB_INTERNAL); 360 *h_errnop = statp->res_h_errno; 361 return (NS_RETURN); 362 } 363 *((struct netent **)rval) = nptr; 364 return (NS_SUCCESS); 365 } 366 *h_errnop = statp->res_h_errno; 367 return (NS_NOTFOUND); 368 } 369 370 int 371 _dns_getnetbyname(void *rval, void *cb_data, va_list ap) 372 { 373 const char *net; 374 char *buffer; 375 size_t buflen; 376 int *errnop, *h_errnop; 377 struct netent *nptr, ne; 378 struct netent_data *ned; 379 int anslen, error; 380 querybuf *buf; 381 char qbuf[MAXDNAME]; 382 res_state statp; 383 384 net = va_arg(ap, const char *); 385 nptr = va_arg(ap, struct netent *); 386 buffer = va_arg(ap, char *); 387 buflen = va_arg(ap, size_t); 388 errnop = va_arg(ap, int *); 389 h_errnop = va_arg(ap, int *); 390 391 statp = __res_state(); 392 if ((statp->options & RES_INIT) == 0 && res_ninit(statp) == -1) { 393 RES_SET_H_ERRNO(statp, NETDB_INTERNAL); 394 *h_errnop = statp->res_h_errno; 395 return (NS_UNAVAIL); 396 } 397 if ((ned = __netent_data_init()) == NULL) { 398 RES_SET_H_ERRNO(statp, NETDB_INTERNAL); 399 *h_errnop = statp->res_h_errno; 400 return (NS_UNAVAIL); 401 } 402 if ((buf = malloc(sizeof(*buf))) == NULL) { 403 RES_SET_H_ERRNO(statp, NETDB_INTERNAL); 404 *h_errnop = statp->res_h_errno; 405 return (NS_NOTFOUND); 406 } 407 408 *((struct netent **)rval) = NULL; 409 410 strncpy(qbuf, net, sizeof(qbuf) - 1); 411 qbuf[sizeof(qbuf) - 1] = '\0'; 412 anslen = res_nsearch(statp, qbuf, C_IN, T_PTR, (u_char *)buf, 413 sizeof(*buf)); 414 if (anslen < 0) { 415 free(buf); 416 #ifdef DEBUG 417 if (statp->options & RES_DEBUG) 418 printf("res_nsearch failed\n"); 419 #endif 420 return (NS_UNAVAIL); 421 } else if (anslen > sizeof(*buf)) { 422 free(buf); 423 #ifdef DEBUG 424 if (statp->options & RES_DEBUG) 425 printf("res_search static buffer too small\n"); 426 #endif 427 return (NS_UNAVAIL); 428 } 429 error = getnetanswer(buf, anslen, BYNAME, &ne, ned, statp); 430 free(buf); 431 if (error != 0) { 432 *h_errnop = statp->res_h_errno; 433 return (NS_NOTFOUND); 434 } 435 if (__copy_netent(&ne, nptr, buffer, buflen) != 0) { 436 *errnop = errno; 437 RES_SET_H_ERRNO(statp, NETDB_INTERNAL); 438 *h_errnop = statp->res_h_errno; 439 return (NS_RETURN); 440 } 441 *((struct netent **)rval) = nptr; 442 return (NS_SUCCESS); 443 } 444 445 void 446 _setnetdnsent(int stayopen) 447 { 448 res_state statp; 449 450 statp = __res_state(); 451 if ((statp->options & RES_INIT) == 0 && res_ninit(statp) == -1) 452 return; 453 if (stayopen) 454 statp->options |= RES_STAYOPEN | RES_USEVC; 455 } 456 457 void 458 _endnetdnsent(void) 459 { 460 res_state statp; 461 462 statp = __res_state(); 463 statp->options &= ~(RES_STAYOPEN | RES_USEVC); 464 res_nclose(statp); 465 } 466