gethostnamadr.c revision 1573
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. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * - 33 * Portions Copyright (c) 1993 by Digital Equipment Corporation. 34 * 35 * Permission to use, copy, modify, and distribute this software for any 36 * purpose with or without fee is hereby granted, provided that the above 37 * copyright notice and this permission notice appear in all copies, and that 38 * the name of Digital Equipment Corporation not be used in advertising or 39 * publicity pertaining to distribution of the document or software without 40 * specific, written prior permission. 41 * 42 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL 43 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES 44 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT 45 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL 46 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR 47 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS 48 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS 49 * SOFTWARE. 50 * - 51 * --Copyright-- 52 */ 53 54#if defined(LIBC_SCCS) && !defined(lint) 55static char sccsid[] = "@(#)gethostnamadr.c 8.1 (Berkeley) 6/4/93"; 56static char rcsid[] = "$Id: gethnamaddr.c,v 4.9.1.1 1993/05/02 22:43:03 vixie Rel $"; 57#endif /* LIBC_SCCS and not lint */ 58 59#include <sys/param.h> 60#include <sys/socket.h> 61#include <netinet/in.h> 62#include <arpa/inet.h> 63#include <arpa/nameser.h> 64#include <netdb.h> 65#include <resolv.h> 66#include <stdio.h> 67#include <ctype.h> 68#include <errno.h> 69#include <string.h> 70 71#define MAXALIASES 35 72#define MAXADDRS 35 73 74static char *h_addr_ptrs[MAXADDRS + 1]; 75 76static struct hostent host; 77static char *host_aliases[MAXALIASES]; 78static char hostbuf[BUFSIZ+1]; 79static struct in_addr host_addr; 80static FILE *hostf = NULL; 81static char hostaddr[MAXADDRS]; 82static char *host_addrs[2]; 83static int stayopen = 0; 84char *strpbrk(); 85 86#if PACKETSZ > 1024 87#define MAXPACKET PACKETSZ 88#else 89#define MAXPACKET 1024 90#endif 91 92typedef union { 93 HEADER hdr; 94 u_char buf[MAXPACKET]; 95} querybuf; 96 97typedef union { 98 int32_t al; 99 char ac; 100} align; 101 102extern int h_errno; 103 104static struct hostent * 105getanswer(answer, anslen, iquery) 106 querybuf *answer; 107 int anslen; 108 int iquery; 109{ 110 register HEADER *hp; 111 register u_char *cp; 112 register int n; 113 u_char *eom; 114 char *bp, **ap; 115 int type, class, buflen, ancount, qdcount; 116 int haveanswer, getclass = C_ANY; 117 char **hap; 118 119 eom = answer->buf + anslen; 120 /* 121 * find first satisfactory answer 122 */ 123 hp = &answer->hdr; 124 ancount = ntohs(hp->ancount); 125 qdcount = ntohs(hp->qdcount); 126 bp = hostbuf; 127 buflen = sizeof(hostbuf); 128 cp = answer->buf + sizeof(HEADER); 129 if (qdcount) { 130 if (iquery) { 131 if ((n = dn_expand((u_char *)answer->buf, 132 (u_char *)eom, (u_char *)cp, (u_char *)bp, 133 buflen)) < 0) { 134 h_errno = NO_RECOVERY; 135 return ((struct hostent *) NULL); 136 } 137 cp += n + QFIXEDSZ; 138 host.h_name = bp; 139 n = strlen(bp) + 1; 140 bp += n; 141 buflen -= n; 142 } else 143 cp += __dn_skipname(cp, eom) + QFIXEDSZ; 144 while (--qdcount > 0) 145 cp += __dn_skipname(cp, eom) + QFIXEDSZ; 146 } else if (iquery) { 147 if (hp->aa) 148 h_errno = HOST_NOT_FOUND; 149 else 150 h_errno = TRY_AGAIN; 151 return ((struct hostent *) NULL); 152 } 153 ap = host_aliases; 154 *ap = NULL; 155 host.h_aliases = host_aliases; 156 hap = h_addr_ptrs; 157 *hap = NULL; 158#if BSD >= 43 || defined(h_addr) /* new-style hostent structure */ 159 host.h_addr_list = h_addr_ptrs; 160#endif 161 haveanswer = 0; 162 while (--ancount >= 0 && cp < eom) { 163 if ((n = dn_expand((u_char *)answer->buf, (u_char *)eom, 164 (u_char *)cp, (u_char *)bp, buflen)) < 0) 165 break; 166 cp += n; 167 type = _getshort(cp); 168 cp += sizeof(u_int16_t); 169 class = _getshort(cp); 170 cp += sizeof(u_int16_t) + sizeof(u_int32_t); 171 n = _getshort(cp); 172 cp += sizeof(u_int16_t); 173 if (type == T_CNAME) { 174 cp += n; 175 if (ap >= &host_aliases[MAXALIASES-1]) 176 continue; 177 *ap++ = bp; 178 n = strlen(bp) + 1; 179 bp += n; 180 buflen -= n; 181 continue; 182 } 183 if (iquery && type == T_PTR) { 184 if ((n = dn_expand((u_char *)answer->buf, 185 (u_char *)eom, (u_char *)cp, (u_char *)bp, 186 buflen)) < 0) 187 break; 188 cp += n; 189 host.h_name = bp; 190 return(&host); 191 } 192 if (iquery || type != T_A) { 193#ifdef DEBUG 194 if (_res.options & RES_DEBUG) 195 printf("unexpected answer type %d, size %d\n", 196 type, n); 197#endif 198 cp += n; 199 continue; 200 } 201 if (haveanswer) { 202 if (n != host.h_length) { 203 cp += n; 204 continue; 205 } 206 if (class != getclass) { 207 cp += n; 208 continue; 209 } 210 } else { 211 host.h_length = n; 212 getclass = class; 213 host.h_addrtype = (class == C_IN) ? AF_INET : AF_UNSPEC; 214 if (!iquery) { 215 host.h_name = bp; 216 bp += strlen(bp) + 1; 217 } 218 } 219 220 bp += sizeof(align) - ((u_int32_t)bp % sizeof(align)); 221 222 if (bp + n >= &hostbuf[sizeof(hostbuf)]) { 223#ifdef DEBUG 224 if (_res.options & RES_DEBUG) 225 printf("size (%d) too big\n", n); 226#endif 227 break; 228 } 229 bcopy(cp, *hap++ = bp, n); 230 bp +=n; 231 cp += n; 232 haveanswer++; 233 } 234 if (haveanswer) { 235 *ap = NULL; 236#if BSD >= 43 || defined(h_addr) /* new-style hostent structure */ 237 *hap = NULL; 238#else 239 host.h_addr = h_addr_ptrs[0]; 240#endif 241 return (&host); 242 } else { 243 h_errno = TRY_AGAIN; 244 return ((struct hostent *) NULL); 245 } 246} 247 248struct hostent * 249gethostbyname(name) 250 const char *name; 251{ 252 querybuf buf; 253 register const char *cp; 254 int n; 255 extern struct hostent *_gethtbyname(); 256 257 /* 258 * disallow names consisting only of digits/dots, unless 259 * they end in a dot. 260 */ 261 if (isdigit(name[0])) 262 for (cp = name;; ++cp) { 263 if (!*cp) { 264 if (*--cp == '.') 265 break; 266 /* 267 * All-numeric, no dot at the end. 268 * Fake up a hostent as if we'd actually 269 * done a lookup. 270 */ 271 if (!inet_aton(name, &host_addr)) { 272 h_errno = HOST_NOT_FOUND; 273 return((struct hostent *) NULL); 274 } 275 host.h_name = (char *)name; 276 host.h_aliases = host_aliases; 277 host_aliases[0] = NULL; 278 host.h_addrtype = AF_INET; 279 host.h_length = sizeof(u_int32_t); 280 h_addr_ptrs[0] = (char *)&host_addr; 281 h_addr_ptrs[1] = (char *)0; 282#if BSD >= 43 || defined(h_addr) /* new-style hostent structure */ 283 host.h_addr_list = h_addr_ptrs; 284#else 285 host.h_addr = h_addr_ptrs[0]; 286#endif 287 return (&host); 288 } 289 if (!isdigit(*cp) && *cp != '.') 290 break; 291 } 292 293 if ((n = res_search(name, C_IN, T_A, buf.buf, sizeof(buf))) < 0) { 294#ifdef DEBUG 295 if (_res.options & RES_DEBUG) 296 printf("res_search failed\n"); 297#endif 298 if (errno == ECONNREFUSED) 299 return (_gethtbyname(name)); 300 else 301 return ((struct hostent *) NULL); 302 } 303 return (getanswer(&buf, n, 0)); 304} 305 306struct hostent * 307gethostbyaddr(addr, len, type) 308 const char *addr; 309 int len, type; 310{ 311 int n; 312 querybuf buf; 313 register struct hostent *hp; 314 char qbuf[MAXDNAME]; 315 extern struct hostent *_gethtbyaddr(); 316 317 if (type != AF_INET) 318 return ((struct hostent *) NULL); 319 (void)sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa", 320 ((unsigned)addr[3] & 0xff), 321 ((unsigned)addr[2] & 0xff), 322 ((unsigned)addr[1] & 0xff), 323 ((unsigned)addr[0] & 0xff)); 324 n = res_query(qbuf, C_IN, T_PTR, (char *)&buf, sizeof(buf)); 325 if (n < 0) { 326#ifdef DEBUG 327 if (_res.options & RES_DEBUG) 328 printf("res_query failed\n"); 329#endif 330 if (errno == ECONNREFUSED) 331 return (_gethtbyaddr(addr, len, type)); 332 return ((struct hostent *) NULL); 333 } 334 hp = getanswer(&buf, n, 1); 335 if (hp == NULL) 336 return ((struct hostent *) NULL); 337 hp->h_addrtype = type; 338 hp->h_length = len; 339 h_addr_ptrs[0] = (char *)&host_addr; 340 h_addr_ptrs[1] = (char *)0; 341 host_addr = *(struct in_addr *)addr; 342#if BSD < 43 && !defined(h_addr) /* new-style hostent structure */ 343 hp->h_addr = h_addr_ptrs[0]; 344#endif 345 return(hp); 346} 347 348void 349_sethtent(f) 350 int f; 351{ 352 if (hostf == NULL) 353 hostf = fopen(_PATH_HOSTS, "r" ); 354 else 355 rewind(hostf); 356 stayopen |= f; 357} 358 359void 360_endhtent() 361{ 362 if (hostf && !stayopen) { 363 (void) fclose(hostf); 364 hostf = NULL; 365 } 366} 367 368struct hostent * 369_gethtent() 370{ 371 char *p; 372 register char *cp, **q; 373 374 if (hostf == NULL && (hostf = fopen(_PATH_HOSTS, "r" )) == NULL) 375 return (NULL); 376again: 377 if ((p = fgets(hostbuf, BUFSIZ, hostf)) == NULL) 378 return (NULL); 379 if (*p == '#') 380 goto again; 381 cp = strpbrk(p, "#\n"); 382 if (cp == NULL) 383 goto again; 384 *cp = '\0'; 385 cp = strpbrk(p, " \t"); 386 if (cp == NULL) 387 goto again; 388 *cp++ = '\0'; 389 /* THIS STUFF IS INTERNET SPECIFIC */ 390#if BSD >= 43 || defined(h_addr) /* new-style hostent structure */ 391 host.h_addr_list = host_addrs; 392#endif 393 host.h_addr = hostaddr; 394 *((u_int32_t *)host.h_addr) = inet_addr(p); 395 host.h_length = sizeof (u_int32_t); 396 host.h_addrtype = AF_INET; 397 while (*cp == ' ' || *cp == '\t') 398 cp++; 399 host.h_name = cp; 400 q = host.h_aliases = host_aliases; 401 cp = strpbrk(cp, " \t"); 402 if (cp != NULL) 403 *cp++ = '\0'; 404 while (cp && *cp) { 405 if (*cp == ' ' || *cp == '\t') { 406 cp++; 407 continue; 408 } 409 if (q < &host_aliases[MAXALIASES - 1]) 410 *q++ = cp; 411 cp = strpbrk(cp, " \t"); 412 if (cp != NULL) 413 *cp++ = '\0'; 414 } 415 *q = NULL; 416 return (&host); 417} 418 419struct hostent * 420_gethtbyname(name) 421 char *name; 422{ 423 register struct hostent *p; 424 register char **cp; 425 426 _sethtent(0); 427 while (p = _gethtent()) { 428 if (strcasecmp(p->h_name, name) == 0) 429 break; 430 for (cp = p->h_aliases; *cp != 0; cp++) 431 if (strcasecmp(*cp, name) == 0) 432 goto found; 433 } 434found: 435 _endhtent(); 436 return (p); 437} 438 439struct hostent * 440_gethtbyaddr(addr, len, type) 441 const char *addr; 442 int len, type; 443{ 444 register struct hostent *p; 445 446 _sethtent(0); 447 while (p = _gethtent()) 448 if (p->h_addrtype == type && !bcmp(p->h_addr, addr, len)) 449 break; 450 _endhtent(); 451 return (p); 452} 453