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 /* Portions Copyright (c) 1993 Carlos Leandro and Rui Salgueiro 54 * Dep. Matematica Universidade de Coimbra, Portugal, Europe 55 * 56 * Permission to use, copy, modify, and distribute this software for any 57 * purpose with or without fee is hereby granted, provided that the above 58 * copyright notice and this permission notice appear in all copies. 59 */ 60 61 #if defined(LIBC_SCCS) && !defined(lint) 62 static char sccsid[] = "@(#)gethostnamadr.c 8.1 (Berkeley) 6/4/93"; 63 #endif /* LIBC_SCCS and not lint */ 64 #include <sys/cdefs.h> 65 __FBSDID("$FreeBSD$"); 66 67 #include <sys/param.h> 68 #include <sys/socket.h> 69 #include <netinet/in.h> 70 #include <arpa/inet.h> 71 #include <arpa/nameser.h> 72 73 #include <errno.h> 74 #include <stdio.h> 75 #include <stdlib.h> 76 #include <netdb.h> 77 #include <resolv.h> 78 #include <ctype.h> 79 #include <string.h> 80 #include <unistd.h> 81 #include <syslog.h> 82 #include <stdarg.h> 83 #include <nsswitch.h> 84 85 #include "res_config.h" 86 87 extern int h_errno; 88 89 #define BYADDR 0 90 #define BYNAME 1 91 #define MAXALIASES 35 92 93 #define MAXPACKET (64*1024) 94 95 typedef union { 96 HEADER hdr; 97 u_char buf[MAXPACKET]; 98 } querybuf; 99 100 typedef union { 101 long al; 102 char ac; 103 } align; 104 105 /* 106 * Reverse the order of first four dotted entries of in. 107 * Out must contain space for at least strlen(in) characters. 108 * The result does not include any leading 0s of in. 109 */ 110 static void 111 ipreverse(char *in, char *out) 112 { 113 char *pos[4]; 114 int len[4]; 115 char *p, *start; 116 int i = 0; 117 int leading = 1; 118 119 /* Fill-in element positions and lengths: pos[], len[]. */ 120 start = p = in; 121 for (;;) { 122 if (*p == '.' || *p == '\0') { 123 /* Leading 0? */ 124 if (leading && p - start == 1 && *start == '0') 125 len[i] = 0; 126 else { 127 len[i] = p - start; 128 leading = 0; 129 } 130 pos[i] = start; 131 start = p + 1; 132 i++; 133 } 134 if (i == 4) 135 break; 136 if (*p == 0) { 137 for (; i < 4; i++) { 138 pos[i] = p; 139 len[i] = 0; 140 } 141 break; 142 } 143 p++; 144 } 145 146 /* Copy the entries in reverse order */ 147 p = out; 148 leading = 1; 149 for (i = 3; i >= 0; i--) { 150 memcpy(p, pos[i], len[i]); 151 if (len[i]) 152 leading = 0; 153 p += len[i]; 154 /* Need a . separator? */ 155 if (!leading && i > 0 && len[i - 1]) 156 *p++ = '.'; 157 } 158 *p = '\0'; 159 } 160 161 static struct netent * 162 getnetanswer(answer, anslen, net_i) 163 querybuf *answer; 164 int anslen; 165 int net_i; 166 { 167 168 HEADER *hp; 169 u_char *cp; 170 int n; 171 u_char *eom; 172 int type, class, ancount, qdcount, haveanswer; 173 char aux[MAXHOSTNAMELEN]; 174 char *in, *bp, *ep, **ap; 175 static struct netent net_entry; 176 static char *net_aliases[MAXALIASES], netbuf[PACKETSZ]; 177 static char ans[MAXHOSTNAMELEN]; 178 179 /* 180 * find first satisfactory answer 181 * 182 * answer --> +------------+ ( MESSAGE ) 183 * | Header | 184 * +------------+ 185 * | Question | the question for the name server 186 * +------------+ 187 * | Answer | RRs answering the question 188 * +------------+ 189 * | Authority | RRs pointing toward an authority 190 * | Additional | RRs holding additional information 191 * +------------+ 192 */ 193 eom = answer->buf + anslen; 194 hp = &answer->hdr; 195 ancount = ntohs(hp->ancount); /* #/records in the answer section */ 196 qdcount = ntohs(hp->qdcount); /* #/entries in the question section */ 197 bp = netbuf; 198 ep = netbuf + sizeof(netbuf); 199 cp = answer->buf + HFIXEDSZ; 200 if (!qdcount) { 201 if (hp->aa) 202 h_errno = HOST_NOT_FOUND; 203 else 204 h_errno = TRY_AGAIN; 205 return (NULL); 206 } 207 while (qdcount-- > 0) 208 cp += __dn_skipname(cp, eom) + QFIXEDSZ; 209 ap = net_aliases; 210 *ap = NULL; 211 net_entry.n_aliases = net_aliases; 212 haveanswer = 0; 213 while (--ancount >= 0 && cp < eom) { 214 n = dn_expand(answer->buf, eom, cp, bp, ep - bp); 215 if ((n < 0) || !res_dnok(bp)) 216 break; 217 cp += n; 218 ans[0] = '\0'; 219 (void)strncpy(&ans[0], bp, sizeof(ans) - 1); 220 ans[sizeof(ans) - 1] = '\0'; 221 GETSHORT(type, cp); 222 GETSHORT(class, cp); 223 cp += INT32SZ; /* TTL */ 224 GETSHORT(n, cp); 225 if (class == C_IN && type == T_PTR) { 226 n = dn_expand(answer->buf, eom, cp, bp, ep - bp); 227 if ((n < 0) || !res_hnok(bp)) { 228 cp += n; 229 return (NULL); 230 } 231 cp += n; 232 *ap++ = bp; 233 n = strlen(bp) + 1; 234 bp += n; 235 net_entry.n_addrtype = 236 (class == C_IN) ? AF_INET : AF_UNSPEC; 237 haveanswer++; 238 } 239 } 240 if (haveanswer) { 241 *ap = NULL; 242 switch (net_i) { 243 case BYADDR: 244 net_entry.n_name = *net_entry.n_aliases; 245 net_entry.n_net = 0L; 246 break; 247 case BYNAME: 248 in = *net_entry.n_aliases; 249 net_entry.n_name = &ans[0]; 250 if (strlen(in) + 1 > sizeof(aux)) { 251 h_errno = NETDB_INTERNAL; 252 errno = ENOBUFS; 253 return (NULL); 254 } 255 ipreverse(in, aux); 256 net_entry.n_net = inet_network(aux); 257 break; 258 } 259 net_entry.n_aliases++; 260 return (&net_entry); 261 } 262 h_errno = TRY_AGAIN; 263 return (NULL); 264 } 265 266 int 267 _dns_getnetbyaddr(void *rval, void *cb_data, va_list ap) 268 { 269 unsigned long net; 270 int net_type; 271 unsigned int netbr[4]; 272 int nn, anslen; 273 querybuf *buf; 274 char qbuf[MAXDNAME]; 275 unsigned long net2; 276 struct netent *net_entry; 277 278 net = va_arg(ap, unsigned long); 279 net_type = va_arg(ap, int); 280 281 *(struct netent **)rval = NULL; 282 283 if (net_type != AF_INET) 284 return NS_UNAVAIL; 285 286 for (nn = 4, net2 = net; net2; net2 >>= 8) 287 netbr[--nn] = net2 & 0xff; 288 switch (nn) { 289 case 3: /* Class A */ 290 sprintf(qbuf, "0.0.0.%u.in-addr.arpa", netbr[3]); 291 break; 292 case 2: /* Class B */ 293 sprintf(qbuf, "0.0.%u.%u.in-addr.arpa", netbr[3], netbr[2]); 294 break; 295 case 1: /* Class C */ 296 sprintf(qbuf, "0.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2], 297 netbr[1]); 298 break; 299 case 0: /* Class D - E */ 300 sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2], 301 netbr[1], netbr[0]); 302 break; 303 } 304 if ((buf = malloc(sizeof(*buf))) == NULL) { 305 h_errno = NETDB_INTERNAL; 306 return NS_NOTFOUND; 307 } 308 anslen = res_query(qbuf, C_IN, T_PTR, (u_char *)buf, sizeof(*buf)); 309 if (anslen < 0) { 310 free(buf); 311 #ifdef DEBUG 312 if (_res.options & RES_DEBUG) 313 printf("res_search failed\n"); 314 #endif 315 return NS_UNAVAIL; 316 } else if (anslen > sizeof(*buf)) { 317 free(buf); 318 #ifdef DEBUG 319 if (_res.options & RES_DEBUG) 320 printf("res_search static buffer too small\n"); 321 #endif 322 return NS_UNAVAIL; 323 } 324 net_entry = getnetanswer(buf, anslen, BYADDR); 325 free(buf); 326 if (net_entry) { 327 unsigned u_net = net; /* maybe net should be unsigned ? */ 328 329 /* Strip trailing zeros */ 330 while ((u_net & 0xff) == 0 && u_net != 0) 331 u_net >>= 8; 332 net_entry->n_net = u_net; 333 *(struct netent **)rval = net_entry; 334 return NS_SUCCESS; 335 } 336 return NS_NOTFOUND; 337 } 338 339 int 340 _dns_getnetbyname(void *rval, void *cb_data, va_list ap) 341 { 342 const char *net; 343 int anslen; 344 querybuf *buf; 345 char qbuf[MAXDNAME]; 346 347 net = va_arg(ap, const char *); 348 349 *(struct netent**)rval = NULL; 350 351 if ((_res.options & RES_INIT) == 0 && res_init() == -1) { 352 h_errno = NETDB_INTERNAL; 353 return NS_UNAVAIL; 354 } 355 if ((buf = malloc(sizeof(*buf))) == NULL) { 356 h_errno = NETDB_INTERNAL; 357 return NS_NOTFOUND; 358 } 359 strncpy(qbuf, net, sizeof(qbuf) - 1); 360 qbuf[sizeof(qbuf) - 1] = '\0'; 361 anslen = res_search(qbuf, C_IN, T_PTR, (u_char *)buf, sizeof(*buf)); 362 if (anslen < 0) { 363 free(buf); 364 #ifdef DEBUG 365 if (_res.options & RES_DEBUG) 366 printf("res_search failed\n"); 367 #endif 368 return NS_UNAVAIL; 369 } else if (anslen > sizeof(*buf)) { 370 free(buf); 371 #ifdef DEBUG 372 if (_res.options & RES_DEBUG) 373 printf("res_search static buffer too small\n"); 374 #endif 375 return NS_UNAVAIL; 376 } 377 *(struct netent**)rval = getnetanswer(buf, anslen, BYNAME); 378 free(buf); 379 return (*(struct netent**)rval != NULL) ? NS_SUCCESS : NS_NOTFOUND; 380 } 381 382 void 383 _setnetdnsent(stayopen) 384 int stayopen; 385 { 386 if (stayopen) 387 _res.options |= RES_STAYOPEN | RES_USEVC; 388 } 389 390 void 391 _endnetdnsent() 392 { 393 _res.options &= ~(RES_STAYOPEN | RES_USEVC); 394 res_close(); 395 } 396