getnetbydns.c revision 146244
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) 62static 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: head/lib/libc/net/getnetbydns.c 146244 2005-05-15 20:15:15Z ume $"); 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 88extern int h_errno; 89 90#define BYADDR 0 91#define BYNAME 1 92 93#define MAXPACKET (64*1024) 94 95typedef union { 96 HEADER hdr; 97 u_char buf[MAXPACKET]; 98} querybuf; 99 100typedef 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 */ 110static void 111ipreverse(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 161static int 162getnetanswer(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#if __LONG_BIT == 64 263 ne->__n_pad0 = 0; /* ABI compatibility */ 264#endif 265 return 0; 266 } 267 h_errno = TRY_AGAIN; 268 return -1; 269} 270 271int 272_dns_getnetbyaddr(void *rval, void *cb_data, va_list ap) 273{ 274 uint32_t net; 275 int net_type; 276 struct netent *ne; 277 struct netent_data *ned; 278 unsigned int netbr[4]; 279 int nn, anslen, error; 280 querybuf *buf; 281 char qbuf[MAXDNAME]; 282 uint32_t net2; 283 284 net = va_arg(ap, uint32_t); 285 net_type = va_arg(ap, int); 286 ne = va_arg(ap, struct netent *); 287 ned = va_arg(ap, struct netent_data *); 288 289 if (net_type != AF_INET) 290 return NS_UNAVAIL; 291 292 for (nn = 4, net2 = net; net2; net2 >>= 8) 293 netbr[--nn] = net2 & 0xff; 294 switch (nn) { 295 case 3: /* Class A */ 296 sprintf(qbuf, "0.0.0.%u.in-addr.arpa", netbr[3]); 297 break; 298 case 2: /* Class B */ 299 sprintf(qbuf, "0.0.%u.%u.in-addr.arpa", netbr[3], netbr[2]); 300 break; 301 case 1: /* Class C */ 302 sprintf(qbuf, "0.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2], 303 netbr[1]); 304 break; 305 case 0: /* Class D - E */ 306 sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2], 307 netbr[1], netbr[0]); 308 break; 309 } 310 if ((buf = malloc(sizeof(*buf))) == NULL) { 311 h_errno = NETDB_INTERNAL; 312 return NS_NOTFOUND; 313 } 314 anslen = res_query(qbuf, C_IN, T_PTR, (u_char *)buf, sizeof(*buf)); 315 if (anslen < 0) { 316 free(buf); 317#ifdef DEBUG 318 if (_res.options & RES_DEBUG) 319 printf("res_search failed\n"); 320#endif 321 return NS_UNAVAIL; 322 } else if (anslen > sizeof(*buf)) { 323 free(buf); 324#ifdef DEBUG 325 if (_res.options & RES_DEBUG) 326 printf("res_search static buffer too small\n"); 327#endif 328 return NS_UNAVAIL; 329 } 330 error = getnetanswer(buf, anslen, BYADDR, ne, ned); 331 free(buf); 332 if (error == 0) { 333 /* Strip trailing zeros */ 334 while ((net & 0xff) == 0 && net != 0) 335 net >>= 8; 336 ne->n_net = net; 337#if __LONG_BIT == 64 338 ne->__n_pad0 = 0; /* ABI compatibility */ 339#endif 340 return NS_SUCCESS; 341 } 342 return NS_NOTFOUND; 343} 344 345int 346_dns_getnetbyname(void *rval, void *cb_data, va_list ap) 347{ 348 const char *net; 349 struct netent *ne; 350 struct netent_data *ned; 351 int anslen, error; 352 querybuf *buf; 353 char qbuf[MAXDNAME]; 354 355 net = va_arg(ap, const char *); 356 ne = va_arg(ap, struct netent *); 357 ned = va_arg(ap, struct netent_data *); 358 359 if ((_res.options & RES_INIT) == 0 && res_init() == -1) { 360 h_errno = NETDB_INTERNAL; 361 return NS_UNAVAIL; 362 } 363 if ((buf = malloc(sizeof(*buf))) == NULL) { 364 h_errno = NETDB_INTERNAL; 365 return NS_NOTFOUND; 366 } 367 strncpy(qbuf, net, sizeof(qbuf) - 1); 368 qbuf[sizeof(qbuf) - 1] = '\0'; 369 anslen = res_search(qbuf, C_IN, T_PTR, (u_char *)buf, sizeof(*buf)); 370 if (anslen < 0) { 371 free(buf); 372#ifdef DEBUG 373 if (_res.options & RES_DEBUG) 374 printf("res_search failed\n"); 375#endif 376 return NS_UNAVAIL; 377 } else if (anslen > sizeof(*buf)) { 378 free(buf); 379#ifdef DEBUG 380 if (_res.options & RES_DEBUG) 381 printf("res_search static buffer too small\n"); 382#endif 383 return NS_UNAVAIL; 384 } 385 error = getnetanswer(buf, anslen, BYNAME, ne, ned); 386 free(buf); 387 return (error == 0) ? NS_SUCCESS : NS_NOTFOUND; 388} 389 390void 391_setnetdnsent(stayopen) 392 int stayopen; 393{ 394 if (stayopen) 395 _res.options |= RES_STAYOPEN | RES_USEVC; 396} 397 398void 399_endnetdnsent() 400{ 401 _res.options &= ~(RES_STAYOPEN | RES_USEVC); 402 res_close(); 403} 404