1 /* 2 * Copyright 2006 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 98 /* Options. Leave them on. */ 99 #define DEBUG 100 101 #if PACKETSZ > 1024 102 #define MAXPACKET PACKETSZ 103 #else 104 #define MAXPACKET 1024 105 #endif 106 107 /* 108 * Formulate a normal query, send, and await answer. 109 * Returned answer is placed in supplied buffer "answer". 110 * Perform preliminary check of answer, returning success only 111 * if no error is indicated and the answer count is nonzero. 112 * Return the size of the response on success, -1 on error. 113 * Error number is left in H_ERRNO. 114 * 115 * Caller must parse answer and determine whether it answers the question. 116 */ 117 int 118 res_nquery(res_state statp, 119 const char *name, /* domain name */ 120 int class, int type, /* class and type of query */ 121 u_char *answer, /* buffer to put answer */ 122 int anslen) /* size of answer buffer */ 123 { 124 u_char buf[MAXPACKET]; 125 HEADER *hp = (HEADER *) answer; 126 int n; 127 u_int oflags; 128 129 oflags = statp->_flags; 130 131 again: 132 hp->rcode = NOERROR; /* default */ 133 134 #ifdef DEBUG 135 if (statp->options & RES_DEBUG) 136 printf(";; res_query(%s, %d, %d)\n", name, class, type); 137 #endif 138 139 n = res_nmkquery(statp, QUERY, name, class, type, NULL, 0, NULL, 140 buf, sizeof(buf)); 141 #ifdef RES_USE_EDNS0 142 if (n > 0 && (statp->_flags & RES_F_EDNS0ERR) == 0 && 143 (statp->options & (RES_USE_EDNS0|RES_USE_DNSSEC)) != 0) 144 n = res_nopt(statp, n, buf, sizeof(buf), anslen); 145 #endif 146 if (n <= 0) { 147 #ifdef DEBUG 148 if (statp->options & RES_DEBUG) 149 printf(";; res_query: mkquery failed\n"); 150 #endif 151 RES_SET_H_ERRNO(statp, NO_RECOVERY); 152 return (n); 153 } 154 n = res_nsend(statp, buf, n, answer, anslen); 155 if (n < 0) { 156 #ifdef RES_USE_EDNS0 157 /* if the query choked with EDNS0, retry without EDNS0 */ 158 if ((statp->options & (RES_USE_EDNS0|RES_USE_DNSSEC)) != 0 && 159 ((oflags ^ statp->_flags) & RES_F_EDNS0ERR) != 0) { 160 statp->_flags |= RES_F_EDNS0ERR; 161 if (statp->options & RES_DEBUG) 162 printf(";; res_nquery: retry without EDNS0\n"); 163 goto again; 164 } 165 #endif 166 #ifdef DEBUG 167 if (statp->options & RES_DEBUG) 168 printf(";; res_query: send error\n"); 169 #endif 170 RES_SET_H_ERRNO(statp, TRY_AGAIN); 171 return (n); 172 } 173 174 if (hp->rcode != NOERROR || ntohs(hp->ancount) == 0) { 175 #ifdef DEBUG 176 if (statp->options & RES_DEBUG) 177 printf(";; rcode = (%s), counts = an:%d ns:%d ar:%d\n", 178 p_rcode(hp->rcode), 179 ntohs(hp->ancount), 180 ntohs(hp->nscount), 181 ntohs(hp->arcount)); 182 #endif 183 switch (hp->rcode) { 184 case NXDOMAIN: 185 RES_SET_H_ERRNO(statp, HOST_NOT_FOUND); 186 break; 187 case SERVFAIL: 188 RES_SET_H_ERRNO(statp, TRY_AGAIN); 189 break; 190 case NOERROR: 191 RES_SET_H_ERRNO(statp, NO_DATA); 192 break; 193 case FORMERR: 194 case NOTIMP: 195 case REFUSED: 196 default: 197 RES_SET_H_ERRNO(statp, NO_RECOVERY); 198 break; 199 } 200 return (-1); 201 } 202 return (n); 203 } 204 205 /* 206 * Formulate a normal query, send, and retrieve answer in supplied buffer. 207 * Return the size of the response on success, -1 on error. 208 * If enabled, implement search rules until answer or unrecoverable failure 209 * is detected. Error code, if any, is left in H_ERRNO. 210 */ 211 int 212 res_nsearch(res_state statp, 213 const char *name, /* domain name */ 214 int class, int type, /* class and type of query */ 215 u_char *answer, /* buffer to put answer */ 216 int anslen) /* size of answer */ 217 { 218 const char *cp, * const *domain; 219 HEADER *hp = (HEADER *) answer; 220 char tmp[NS_MAXDNAME]; 221 u_int dots; 222 int trailing_dot, ret, saved_herrno; 223 int got_nodata = 0, got_servfail = 0, root_on_list = 0; 224 int tried_as_is = 0; 225 int searched = 0; 226 227 errno = 0; 228 RES_SET_H_ERRNO(statp, HOST_NOT_FOUND); /* True if we never query. */ 229 230 dots = 0; 231 for (cp = name; *cp != '\0'; cp++) 232 dots += (*cp == '.'); 233 trailing_dot = 0; 234 if (cp > name && *--cp == '.') 235 trailing_dot++; 236 237 /* If there aren't any dots, it could be a user-level alias. */ 238 if (!dots && (cp = res_hostalias(statp, name, tmp, sizeof tmp))!= NULL) 239 return (res_nquery(statp, cp, class, type, answer, anslen)); 240 241 /* 242 * If there are enough dots in the name, let's just give it a 243 * try 'as is'. The threshold can be set with the "ndots" option. 244 * Also, query 'as is', if there is a trailing dot in the name. 245 */ 246 saved_herrno = -1; 247 if (dots >= statp->ndots || trailing_dot) { 248 ret = res_nquerydomain(statp, name, NULL, class, type, 249 answer, anslen); 250 if (ret > 0 || trailing_dot) 251 return (ret); 252 saved_herrno = statp->res_h_errno; 253 tried_as_is++; 254 } 255 256 /* 257 * We do at least one level of search if 258 * - there is no dot and RES_DEFNAME is set, or 259 * - there is at least one dot, there is no trailing dot, 260 * and RES_DNSRCH is set. 261 */ 262 if ((!dots && (statp->options & RES_DEFNAMES) != 0) || 263 (dots && !trailing_dot && (statp->options & RES_DNSRCH) != 0)) { 264 int done = 0; 265 266 for (domain = (const char * const *)statp->dnsrch; 267 *domain && !done; 268 domain++) { 269 searched = 1; 270 271 if (domain[0][0] == '\0' || 272 (domain[0][0] == '.' && domain[0][1] == '\0')) 273 root_on_list++; 274 275 ret = res_nquerydomain(statp, name, *domain, 276 class, type, 277 answer, anslen); 278 if (ret > 0) 279 return (ret); 280 281 /* 282 * If no server present, give up. 283 * If name isn't found in this domain, 284 * keep trying higher domains in the search list 285 * (if that's enabled). 286 * On a NO_DATA error, keep trying, otherwise 287 * a wildcard entry of another type could keep us 288 * from finding this entry higher in the domain. 289 * If we get some other error (negative answer or 290 * server failure), then stop searching up, 291 * but try the input name below in case it's 292 * fully-qualified. 293 */ 294 if (errno == ECONNREFUSED) { 295 RES_SET_H_ERRNO(statp, TRY_AGAIN); 296 return (-1); 297 } 298 299 switch (statp->res_h_errno) { 300 case NO_DATA: 301 got_nodata++; 302 /* FALLTHROUGH */ 303 case HOST_NOT_FOUND: 304 /* keep trying */ 305 break; 306 case TRY_AGAIN: 307 if (hp->rcode == SERVFAIL) { 308 /* try next search element, if any */ 309 got_servfail++; 310 break; 311 } 312 /* FALLTHROUGH */ 313 default: 314 /* anything else implies that we're done */ 315 done++; 316 } 317 318 /* if we got here for some reason other than DNSRCH, 319 * we only wanted one iteration of the loop, so stop. 320 */ 321 if ((statp->options & RES_DNSRCH) == 0) 322 done++; 323 } 324 } 325 326 /* 327 * If the query has not already been tried as is then try it 328 * unless RES_NOTLDQUERY is set and there were no dots. 329 */ 330 if ((dots || !searched || (statp->options & RES_NOTLDQUERY) == 0) && 331 !(tried_as_is || root_on_list)) { 332 ret = res_nquerydomain(statp, name, NULL, class, type, 333 answer, anslen); 334 if (ret > 0) 335 return (ret); 336 } 337 338 /* if we got here, we didn't satisfy the search. 339 * if we did an initial full query, return that query's H_ERRNO 340 * (note that we wouldn't be here if that query had succeeded). 341 * else if we ever got a nodata, send that back as the reason. 342 * else send back meaningless H_ERRNO, that being the one from 343 * the last DNSRCH we did. 344 */ 345 if (saved_herrno != -1) 346 RES_SET_H_ERRNO(statp, saved_herrno); 347 else if (got_nodata) 348 RES_SET_H_ERRNO(statp, NO_DATA); 349 else if (got_servfail) 350 RES_SET_H_ERRNO(statp, TRY_AGAIN); 351 return (-1); 352 } 353 354 /* 355 * Perform a call on res_query on the concatenation of name and domain, 356 * removing a trailing dot from name if domain is NULL. 357 */ 358 int 359 res_nquerydomain(res_state statp, 360 const char *name, 361 const char *domain, 362 int class, int type, /* class and type of query */ 363 u_char *answer, /* buffer to put answer */ 364 int anslen) /* size of answer */ 365 { 366 char nbuf[MAXDNAME]; 367 const char *longname = nbuf; 368 int n, d; 369 370 #ifdef DEBUG 371 if (statp->options & RES_DEBUG) 372 printf(";; res_nquerydomain(%s, %s, %d, %d)\n", 373 name, domain?domain:"<Nil>", class, type); 374 #endif 375 if (domain == NULL) { 376 /* 377 * Check for trailing '.'; 378 * copy without '.' if present. 379 */ 380 n = strlen(name); 381 if (n >= MAXDNAME) { 382 RES_SET_H_ERRNO(statp, NO_RECOVERY); 383 return (-1); 384 } 385 n--; 386 if (n >= 0 && name[n] == '.') { 387 strncpy(nbuf, name, n); 388 nbuf[n] = '\0'; 389 } else 390 longname = name; 391 } else { 392 n = strlen(name); 393 d = strlen(domain); 394 if (n + d + 1 >= MAXDNAME) { 395 RES_SET_H_ERRNO(statp, NO_RECOVERY); 396 return (-1); 397 } 398 sprintf(nbuf, "%s.%s", name, domain); 399 } 400 return (res_nquery(statp, longname, class, type, answer, anslen)); 401 } 402 403 const char * 404 res_hostalias(const res_state statp, const char *name, char *dst, size_t siz) { 405 char *file, *cp1, *cp2; 406 char buf[BUFSIZ]; 407 FILE *fp; 408 409 if (statp->options & RES_NOALIASES) 410 return (NULL); 411 file = getenv("HOSTALIASES"); 412 #ifdef SUNW_AVOIDSTDIO_FDLIMIT 413 if (file == NULL || (fp = fopen(file, "rF")) == NULL) 414 #else 415 if (file == NULL || (fp = fopen(file, "r")) == NULL) 416 #endif 417 return (NULL); 418 setbuf(fp, NULL); 419 buf[sizeof(buf) - 1] = '\0'; 420 while (fgets(buf, sizeof(buf), fp)) { 421 for (cp1 = buf; *cp1 && !isspace((unsigned char)*cp1); ++cp1) 422 ; 423 if (!*cp1) 424 break; 425 *cp1 = '\0'; 426 if (ns_samename(buf, name) == 1) { 427 while (isspace((unsigned char)*++cp1)) 428 ; 429 if (!*cp1) 430 break; 431 for (cp2 = cp1 + 1; *cp2 && 432 !isspace((unsigned char)*cp2); ++cp2) 433 ; 434 *cp2 = '\0'; 435 strncpy(dst, cp1, siz - 1); 436 dst[siz - 1] = '\0'; 437 fclose(fp); 438 return (dst); 439 } 440 } 441 fclose(fp); 442 return (NULL); 443 } 444