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 "netdb_private.h" 86 #include "res_config.h" 87 88 extern int h_errno; 89 90 #define BYADDR 0 91 #define BYNAME 1 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 int 162 getnetanswer(querybuf *answer, int anslen, int net_i, struct netent *ne, 163 struct netent_data *ned) 164 { 165 166 HEADER *hp; 167 u_char *cp; 168 int n; 169 u_char *eom; 170 int type, class, ancount, qdcount, haveanswer; 171 char aux[MAXHOSTNAMELEN]; 172 char ans[MAXHOSTNAMELEN]; 173 char *in, *bp, *ep, **ap; 174 175 /* 176 * find first satisfactory answer 177 * 178 * answer --> +------------+ ( MESSAGE ) 179 * | Header | 180 * +------------+ 181 * | Question | the question for the name server 182 * +------------+ 183 * | Answer | RRs answering the question 184 * +------------+ 185 * | Authority | RRs pointing toward an authority 186 * | Additional | RRs holding additional information 187 * +------------+ 188 */ 189 eom = answer->buf + anslen; 190 hp = &answer->hdr; 191 ancount = ntohs(hp->ancount); /* #/records in the answer section */ 192 qdcount = ntohs(hp->qdcount); /* #/entries in the question section */ 193 bp = ned->netbuf; 194 ep = ned->netbuf + sizeof(ned->netbuf); 195 cp = answer->buf + HFIXEDSZ; 196 if (!qdcount) { 197 if (hp->aa) 198 h_errno = HOST_NOT_FOUND; 199 else 200 h_errno = TRY_AGAIN; 201 return -1; 202 } 203 while (qdcount-- > 0) 204 cp += __dn_skipname(cp, eom) + QFIXEDSZ; 205 ap = ned->net_aliases; 206 *ap = NULL; 207 ne->n_aliases = ned->net_aliases; 208 haveanswer = 0; 209 while (--ancount >= 0 && cp < eom) { 210 n = dn_expand(answer->buf, eom, cp, bp, ep - bp); 211 if ((n < 0) || !res_dnok(bp)) 212 break; 213 cp += n; 214 ans[0] = '\0'; 215 (void)strncpy(&ans[0], bp, sizeof(ans) - 1); 216 ans[sizeof(ans) - 1] = '\0'; 217 GETSHORT(type, cp); 218 GETSHORT(class, cp); 219 cp += INT32SZ; /* TTL */ 220 GETSHORT(n, cp); 221 if (class == C_IN && type == T_PTR) { 222 n = dn_expand(answer->buf, eom, cp, bp, ep - bp); 223 if ((n < 0) || !res_hnok(bp)) { 224 cp += n; 225 return -1; 226 } 227 cp += n; 228 *ap++ = bp; 229 n = strlen(bp) + 1; 230 bp += n; 231 ne->n_addrtype = (class == C_IN) ? AF_INET : AF_UNSPEC; 232 haveanswer++; 233 } 234 } 235 if (haveanswer) { 236 *ap = NULL; 237 switch (net_i) { 238 case BYADDR: 239 ne->n_name = *ne->n_aliases; 240 ne->n_net = 0L; 241 break; 242 case BYNAME: 243 in = *ne->n_aliases; 244 n = strlen(ans) + 1; 245 if (ep - bp < n) { 246 h_errno = NETDB_INTERNAL; 247 errno = ENOBUFS; 248 return -1; 249 } 250 strlcpy(bp, ans, ep - bp); 251 ne->n_name = bp; 252 if (strlen(in) + 1 > sizeof(aux)) { 253 h_errno = NETDB_INTERNAL; 254 errno = ENOBUFS; 255 return -1; 256 } 257 ipreverse(in, aux); 258 ne->n_net = inet_network(aux); 259 break; 260 } 261 ne->n_aliases++; 262 return 0; 263 } 264 h_errno = TRY_AGAIN; 265 return -1; 266 } 267 268 int 269 _dns_getnetbyaddr(void *rval, void *cb_data, va_list ap) 270 { 271 uint32_t net; 272 int net_type; 273 struct netent *ne; 274 struct netent_data *ned; 275 unsigned int netbr[4]; 276 int nn, anslen, error; 277 querybuf *buf; 278 char qbuf[MAXDNAME]; 279 uint32_t net2; 280 281 net = va_arg(ap, uint32_t); 282 net_type = va_arg(ap, int); 283 ne = va_arg(ap, struct netent *); 284 ned = va_arg(ap, struct netent_data *); 285 286 if (net_type != AF_INET) 287 return NS_UNAVAIL; 288 289 for (nn = 4, net2 = net; net2; net2 >>= 8) 290 netbr[--nn] = net2 & 0xff; 291 switch (nn) { 292 case 3: /* Class A */ 293 sprintf(qbuf, "0.0.0.%u.in-addr.arpa", netbr[3]); 294 break; 295 case 2: /* Class B */ 296 sprintf(qbuf, "0.0.%u.%u.in-addr.arpa", netbr[3], netbr[2]); 297 break; 298 case 1: /* Class C */ 299 sprintf(qbuf, "0.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2], 300 netbr[1]); 301 break; 302 case 0: /* Class D - E */ 303 sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2], 304 netbr[1], netbr[0]); 305 break; 306 } 307 if ((buf = malloc(sizeof(*buf))) == NULL) { 308 h_errno = NETDB_INTERNAL; 309 return NS_NOTFOUND; 310 } 311 anslen = res_query(qbuf, C_IN, T_PTR, (u_char *)buf, sizeof(*buf)); 312 if (anslen < 0) { 313 free(buf); 314 #ifdef DEBUG 315 if (_res.options & RES_DEBUG) 316 printf("res_search failed\n"); 317 #endif 318 return NS_UNAVAIL; 319 } else if (anslen > sizeof(*buf)) { 320 free(buf); 321 #ifdef DEBUG 322 if (_res.options & RES_DEBUG) 323 printf("res_search static buffer too small\n"); 324 #endif 325 return NS_UNAVAIL; 326 } 327 error = getnetanswer(buf, anslen, BYADDR, ne, ned); 328 free(buf); 329 if (error == 0) { 330 /* Strip trailing zeros */ 331 while ((net & 0xff) == 0 && net != 0) 332 net >>= 8; 333 ne->n_net = net; 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 struct netent *ne; 344 struct netent_data *ned; 345 int anslen, error; 346 querybuf *buf; 347 char qbuf[MAXDNAME]; 348 349 net = va_arg(ap, const char *); 350 ne = va_arg(ap, struct netent *); 351 ned = va_arg(ap, struct netent_data *); 352 353 if ((_res.options & RES_INIT) == 0 && res_init() == -1) { 354 h_errno = NETDB_INTERNAL; 355 return NS_UNAVAIL; 356 } 357 if ((buf = malloc(sizeof(*buf))) == NULL) { 358 h_errno = NETDB_INTERNAL; 359 return NS_NOTFOUND; 360 } 361 strncpy(qbuf, net, sizeof(qbuf) - 1); 362 qbuf[sizeof(qbuf) - 1] = '\0'; 363 anslen = res_search(qbuf, C_IN, T_PTR, (u_char *)buf, sizeof(*buf)); 364 if (anslen < 0) { 365 free(buf); 366 #ifdef DEBUG 367 if (_res.options & RES_DEBUG) 368 printf("res_search failed\n"); 369 #endif 370 return NS_UNAVAIL; 371 } else if (anslen > sizeof(*buf)) { 372 free(buf); 373 #ifdef DEBUG 374 if (_res.options & RES_DEBUG) 375 printf("res_search static buffer too small\n"); 376 #endif 377 return NS_UNAVAIL; 378 } 379 error = getnetanswer(buf, anslen, BYNAME, ne, ned); 380 free(buf); 381 return (error == 0) ? NS_SUCCESS : NS_NOTFOUND; 382 } 383 384 void 385 _setnetdnsent(stayopen) 386 int stayopen; 387 { 388 if (stayopen) 389 _res.options |= RES_STAYOPEN | RES_USEVC; 390 } 391 392 void 393 _endnetdnsent() 394 { 395 _res.options &= ~(RES_STAYOPEN | RES_USEVC); 396 res_close(); 397 } 398