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