1 /* 2 * Copyright 2003 Sun Microsystems, Inc. All rights reserved. 3 * Use is subject to license terms. 4 */ 5 6 /* 7 * Copyright (c) 1988, 1993 8 * The Regents of the University of California. All rights reserved. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 /* 40 * Portions Copyright (c) 1993 by Digital Equipment Corporation. 41 * 42 * Permission to use, copy, modify, and distribute this software for any 43 * purpose with or without fee is hereby granted, provided that the above 44 * copyright notice and this permission notice appear in all copies, and that 45 * the name of Digital Equipment Corporation not be used in advertising or 46 * publicity pertaining to distribution of the document or software without 47 * specific, written prior permission. 48 * 49 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL 50 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES 51 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT 52 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL 53 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR 54 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS 55 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS 56 * SOFTWARE. 57 */ 58 59 /* 60 * Portions Copyright (c) 1996-1999 by Internet Software Consortium. 61 * 62 * Permission to use, copy, modify, and distribute this software for any 63 * purpose with or without fee is hereby granted, provided that the above 64 * copyright notice and this permission notice appear in all copies. 65 * 66 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS 67 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES 68 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE 69 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL 70 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR 71 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS 72 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS 73 * SOFTWARE. 74 */ 75 76 #pragma ident "%Z%%M% %I% %E% SMI" 77 78 #if defined(LIBC_SCCS) && !defined(lint) 79 static const char sccsid[] = "@(#)res_query.c 8.1 (Berkeley) 6/4/93"; 80 static const char rcsid[] = "$Id: res_query.c,v 8.24 2003/01/31 15:25:58 vixie Exp $"; 81 #endif /* LIBC_SCCS and not lint */ 82 83 #include "port_before.h" 84 #include <sys/types.h> 85 #include <sys/param.h> 86 #include <netinet/in.h> 87 #include <arpa/inet.h> 88 #include <arpa/nameser.h> 89 #include <ctype.h> 90 #include <errno.h> 91 #include <netdb.h> 92 #include <resolv.h> 93 #include <stdio.h> 94 #include <stdlib.h> 95 #include <string.h> 96 #include "port_after.h" 97 #ifdef SUNW_AVOIDSTDIO_FDLIMIT 98 #include "../../../libnsl/include/nsl_stdio_prv.h" 99 #endif 100 101 /* Options. Leave them on. */ 102 #define DEBUG 103 104 #if PACKETSZ > 1024 105 #define MAXPACKET PACKETSZ 106 #else 107 #define MAXPACKET 1024 108 #endif 109 110 /* 111 * Formulate a normal query, send, and await answer. 112 * Returned answer is placed in supplied buffer "answer". 113 * Perform preliminary check of answer, returning success only 114 * if no error is indicated and the answer count is nonzero. 115 * Return the size of the response on success, -1 on error. 116 * Error number is left in H_ERRNO. 117 * 118 * Caller must parse answer and determine whether it answers the question. 119 */ 120 int 121 res_nquery(res_state statp, 122 const char *name, /* domain name */ 123 int class, int type, /* class and type of query */ 124 u_char *answer, /* buffer to put answer */ 125 int anslen) /* size of answer buffer */ 126 { 127 u_char buf[MAXPACKET]; 128 HEADER *hp = (HEADER *) answer; 129 int n; 130 u_int oflags; 131 132 oflags = statp->_flags; 133 134 again: 135 hp->rcode = NOERROR; /* default */ 136 137 #ifdef DEBUG 138 if (statp->options & RES_DEBUG) 139 printf(";; res_query(%s, %d, %d)\n", name, class, type); 140 #endif 141 142 n = res_nmkquery(statp, QUERY, name, class, type, NULL, 0, NULL, 143 buf, sizeof(buf)); 144 #ifdef RES_USE_EDNS0 145 if (n > 0 && (statp->_flags & RES_F_EDNS0ERR) == 0 && 146 (statp->options & (RES_USE_EDNS0|RES_USE_DNSSEC)) != 0) 147 n = res_nopt(statp, n, buf, sizeof(buf), anslen); 148 #endif 149 if (n <= 0) { 150 #ifdef DEBUG 151 if (statp->options & RES_DEBUG) 152 printf(";; res_query: mkquery failed\n"); 153 #endif 154 RES_SET_H_ERRNO(statp, NO_RECOVERY); 155 return (n); 156 } 157 n = res_nsend(statp, buf, n, answer, anslen); 158 if (n < 0) { 159 #ifdef RES_USE_EDNS0 160 /* if the query choked with EDNS0, retry without EDNS0 */ 161 if ((statp->options & (RES_USE_EDNS0|RES_USE_DNSSEC)) != 0 && 162 ((oflags ^ statp->_flags) & RES_F_EDNS0ERR) != 0) { 163 statp->_flags |= RES_F_EDNS0ERR; 164 if (statp->options & RES_DEBUG) 165 printf(";; res_nquery: retry without EDNS0\n"); 166 goto again; 167 } 168 #endif 169 #ifdef DEBUG 170 if (statp->options & RES_DEBUG) 171 printf(";; res_query: send error\n"); 172 #endif 173 RES_SET_H_ERRNO(statp, TRY_AGAIN); 174 return (n); 175 } 176 177 if (hp->rcode != NOERROR || ntohs(hp->ancount) == 0) { 178 #ifdef DEBUG 179 if (statp->options & RES_DEBUG) 180 printf(";; rcode = (%s), counts = an:%d ns:%d ar:%d\n", 181 p_rcode(hp->rcode), 182 ntohs(hp->ancount), 183 ntohs(hp->nscount), 184 ntohs(hp->arcount)); 185 #endif 186 switch (hp->rcode) { 187 case NXDOMAIN: 188 RES_SET_H_ERRNO(statp, HOST_NOT_FOUND); 189 break; 190 case SERVFAIL: 191 RES_SET_H_ERRNO(statp, TRY_AGAIN); 192 break; 193 case NOERROR: 194 RES_SET_H_ERRNO(statp, NO_DATA); 195 break; 196 case FORMERR: 197 case NOTIMP: 198 case REFUSED: 199 default: 200 RES_SET_H_ERRNO(statp, NO_RECOVERY); 201 break; 202 } 203 return (-1); 204 } 205 return (n); 206 } 207 208 /* 209 * Formulate a normal query, send, and retrieve answer in supplied buffer. 210 * Return the size of the response on success, -1 on error. 211 * If enabled, implement search rules until answer or unrecoverable failure 212 * is detected. Error code, if any, is left in H_ERRNO. 213 */ 214 int 215 res_nsearch(res_state statp, 216 const char *name, /* domain name */ 217 int class, int type, /* class and type of query */ 218 u_char *answer, /* buffer to put answer */ 219 int anslen) /* size of answer */ 220 { 221 const char *cp, * const *domain; 222 HEADER *hp = (HEADER *) answer; 223 char tmp[NS_MAXDNAME]; 224 u_int dots; 225 int trailing_dot, ret, saved_herrno; 226 int got_nodata = 0, got_servfail = 0, root_on_list = 0; 227 int tried_as_is = 0; 228 int searched = 0; 229 230 errno = 0; 231 RES_SET_H_ERRNO(statp, HOST_NOT_FOUND); /* True if we never query. */ 232 233 dots = 0; 234 for (cp = name; *cp != '\0'; cp++) 235 dots += (*cp == '.'); 236 trailing_dot = 0; 237 if (cp > name && *--cp == '.') 238 trailing_dot++; 239 240 /* If there aren't any dots, it could be a user-level alias. */ 241 if (!dots && (cp = res_hostalias(statp, name, tmp, sizeof tmp))!= NULL) 242 return (res_nquery(statp, cp, class, type, answer, anslen)); 243 244 /* 245 * If there are enough dots in the name, let's just give it a 246 * try 'as is'. The threshold can be set with the "ndots" option. 247 * Also, query 'as is', if there is a trailing dot in the name. 248 */ 249 saved_herrno = -1; 250 if (dots >= statp->ndots || trailing_dot) { 251 ret = res_nquerydomain(statp, name, NULL, class, type, 252 answer, anslen); 253 if (ret > 0 || trailing_dot) 254 return (ret); 255 saved_herrno = statp->res_h_errno; 256 tried_as_is++; 257 } 258 259 /* 260 * We do at least one level of search if 261 * - there is no dot and RES_DEFNAME is set, or 262 * - there is at least one dot, there is no trailing dot, 263 * and RES_DNSRCH is set. 264 */ 265 if ((!dots && (statp->options & RES_DEFNAMES) != 0) || 266 (dots && !trailing_dot && (statp->options & RES_DNSRCH) != 0)) { 267 int done = 0; 268 269 for (domain = (const char * const *)statp->dnsrch; 270 *domain && !done; 271 domain++) { 272 searched = 1; 273 274 if (domain[0][0] == '\0' || 275 (domain[0][0] == '.' && domain[0][1] == '\0')) 276 root_on_list++; 277 278 ret = res_nquerydomain(statp, name, *domain, 279 class, type, 280 answer, anslen); 281 if (ret > 0) 282 return (ret); 283 284 /* 285 * If no server present, give up. 286 * If name isn't found in this domain, 287 * keep trying higher domains in the search list 288 * (if that's enabled). 289 * On a NO_DATA error, keep trying, otherwise 290 * a wildcard entry of another type could keep us 291 * from finding this entry higher in the domain. 292 * If we get some other error (negative answer or 293 * server failure), then stop searching up, 294 * but try the input name below in case it's 295 * fully-qualified. 296 */ 297 if (errno == ECONNREFUSED) { 298 RES_SET_H_ERRNO(statp, TRY_AGAIN); 299 return (-1); 300 } 301 302 switch (statp->res_h_errno) { 303 case NO_DATA: 304 got_nodata++; 305 /* FALLTHROUGH */ 306 case HOST_NOT_FOUND: 307 /* keep trying */ 308 break; 309 case TRY_AGAIN: 310 if (hp->rcode == SERVFAIL) { 311 /* try next search element, if any */ 312 got_servfail++; 313 break; 314 } 315 /* FALLTHROUGH */ 316 default: 317 /* anything else implies that we're done */ 318 done++; 319 } 320 321 /* if we got here for some reason other than DNSRCH, 322 * we only wanted one iteration of the loop, so stop. 323 */ 324 if ((statp->options & RES_DNSRCH) == 0) 325 done++; 326 } 327 } 328 329 /* 330 * If the query has not already been tried as is then try it 331 * unless RES_NOTLDQUERY is set and there were no dots. 332 */ 333 if ((dots || !searched || (statp->options & RES_NOTLDQUERY) == 0) && 334 !(tried_as_is || root_on_list)) { 335 ret = res_nquerydomain(statp, name, NULL, class, type, 336 answer, anslen); 337 if (ret > 0) 338 return (ret); 339 } 340 341 /* if we got here, we didn't satisfy the search. 342 * if we did an initial full query, return that query's H_ERRNO 343 * (note that we wouldn't be here if that query had succeeded). 344 * else if we ever got a nodata, send that back as the reason. 345 * else send back meaningless H_ERRNO, that being the one from 346 * the last DNSRCH we did. 347 */ 348 if (saved_herrno != -1) 349 RES_SET_H_ERRNO(statp, saved_herrno); 350 else if (got_nodata) 351 RES_SET_H_ERRNO(statp, NO_DATA); 352 else if (got_servfail) 353 RES_SET_H_ERRNO(statp, TRY_AGAIN); 354 return (-1); 355 } 356 357 /* 358 * Perform a call on res_query on the concatenation of name and domain, 359 * removing a trailing dot from name if domain is NULL. 360 */ 361 int 362 res_nquerydomain(res_state statp, 363 const char *name, 364 const char *domain, 365 int class, int type, /* class and type of query */ 366 u_char *answer, /* buffer to put answer */ 367 int anslen) /* size of answer */ 368 { 369 char nbuf[MAXDNAME]; 370 const char *longname = nbuf; 371 int n, d; 372 373 #ifdef DEBUG 374 if (statp->options & RES_DEBUG) 375 printf(";; res_nquerydomain(%s, %s, %d, %d)\n", 376 name, domain?domain:"<Nil>", class, type); 377 #endif 378 if (domain == NULL) { 379 /* 380 * Check for trailing '.'; 381 * copy without '.' if present. 382 */ 383 n = strlen(name); 384 if (n >= MAXDNAME) { 385 RES_SET_H_ERRNO(statp, NO_RECOVERY); 386 return (-1); 387 } 388 n--; 389 if (n >= 0 && name[n] == '.') { 390 strncpy(nbuf, name, n); 391 nbuf[n] = '\0'; 392 } else 393 longname = name; 394 } else { 395 n = strlen(name); 396 d = strlen(domain); 397 if (n + d + 1 >= MAXDNAME) { 398 RES_SET_H_ERRNO(statp, NO_RECOVERY); 399 return (-1); 400 } 401 sprintf(nbuf, "%s.%s", name, domain); 402 } 403 return (res_nquery(statp, longname, class, type, answer, anslen)); 404 } 405 406 const char * 407 res_hostalias(const res_state statp, const char *name, char *dst, size_t siz) { 408 char *file, *cp1, *cp2; 409 char buf[BUFSIZ]; 410 #ifdef SUNW_AVOIDSTDIO_FDLIMIT 411 __NSL_FILE *fp; 412 #else 413 FILE *fp; 414 #endif 415 416 if (statp->options & RES_NOALIASES) 417 return (NULL); 418 file = getenv("HOSTALIASES"); 419 #ifdef SUNW_AVOIDSTDIO_FDLIMIT 420 if (file == NULL || (fp = __nsl_fopen(file, "r")) == NULL) 421 #else 422 if (file == NULL || (fp = fopen(file, "r")) == NULL) 423 #endif 424 return (NULL); 425 #ifndef SUNW_AVOIDSTDIO_FDLIMIT 426 setbuf(fp, NULL); 427 #endif 428 buf[sizeof(buf) - 1] = '\0'; 429 #ifdef SUNW_AVOIDSTDIO_FDLIMIT 430 while (__nsl_fgets(buf, sizeof(buf), fp)) { 431 #else 432 while (fgets(buf, sizeof(buf), fp)) { 433 #endif 434 for (cp1 = buf; *cp1 && !isspace((unsigned char)*cp1); ++cp1) 435 ; 436 if (!*cp1) 437 break; 438 *cp1 = '\0'; 439 if (ns_samename(buf, name) == 1) { 440 while (isspace((unsigned char)*++cp1)) 441 ; 442 if (!*cp1) 443 break; 444 for (cp2 = cp1 + 1; *cp2 && 445 !isspace((unsigned char)*cp2); ++cp2) 446 ; 447 *cp2 = '\0'; 448 strncpy(dst, cp1, siz - 1); 449 dst[siz - 1] = '\0'; 450 #ifdef SUNW_AVOIDSTDIO_FDLIMIT 451 __nsl_fclose(fp); 452 #else 453 fclose(fp); 454 #endif 455 return (dst); 456 } 457 } 458 #ifdef SUNW_AVOIDSTDIO_FDLIMIT 459 __nsl_fclose(fp); 460 #else 461 fclose(fp); 462 #endif 463 return (NULL); 464 } 465