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 * 4. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 * -
29 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
30 *
31 * Permission to use, copy, modify, and distribute this software for any
32 * purpose with or without fee is hereby granted, provided that the above
33 * copyright notice and this permission notice appear in all copies, and that
34 * the name of Digital Equipment Corporation not be used in advertising or
35 * publicity pertaining to distribution of the document or software without
36 * specific, written prior permission.
37 *
38 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
39 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
40 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
41 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
42 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
43 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
44 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
45 * SOFTWARE.
46 * -
47 * --Copyright--
48 */
49 /* Portions Copyright (c) 1993 Carlos Leandro and Rui Salgueiro
50 * Dep. Matematica Universidade de Coimbra, Portugal, Europe
51 *
52 * Permission to use, copy, modify, and distribute this software for any
53 * purpose with or without fee is hereby granted, provided that the above
54 * copyright notice and this permission notice appear in all copies.
55 */
56
57 #if defined(LIBC_SCCS) && !defined(lint)
58 static char sccsid[] = "@(#)gethostnamadr.c 8.1 (Berkeley) 6/4/93";
59 #endif /* LIBC_SCCS and not lint */
60 #include <sys/cdefs.h>
61 __FBSDID("$FreeBSD$");
62
63 #include <sys/param.h>
64 #include <sys/socket.h>
65 #include <netinet/in.h>
66 #include <arpa/inet.h>
67 #include <arpa/nameser.h>
68
69 #include <errno.h>
70 #include <stdio.h>
71 #include <stdlib.h>
72 #include <netdb.h>
73 #include <resolv.h>
74 #include <ctype.h>
75 #include <string.h>
76 #include <unistd.h>
77 #include <syslog.h>
78 #include <stdarg.h>
79 #include <nsswitch.h>
80
81 #include "netdb_private.h"
82 #include "res_config.h"
83
84 #define BYADDR 0
85 #define BYNAME 1
86
87 #define MAXPACKET (64*1024)
88
89 typedef union {
90 HEADER hdr;
91 u_char buf[MAXPACKET];
92 } querybuf;
93
94 typedef union {
95 long al;
96 char ac;
97 } align;
98
99 /*
100 * Reverse the order of first four dotted entries of in.
101 * Out must contain space for at least strlen(in) characters.
102 * The result does not include any leading 0s of in.
103 */
104 static void
ipreverse(char * in,char * out)105 ipreverse(char *in, char *out)
106 {
107 char *pos[4];
108 int len[4];
109 char *p, *start;
110 int i = 0;
111 int leading = 1;
112
113 /* Fill-in element positions and lengths: pos[], len[]. */
114 start = p = in;
115 for (;;) {
116 if (*p == '.' || *p == '\0') {
117 /* Leading 0? */
118 if (leading && p - start == 1 && *start == '0')
119 len[i] = 0;
120 else {
121 len[i] = p - start;
122 leading = 0;
123 }
124 pos[i] = start;
125 start = p + 1;
126 i++;
127 }
128 if (i == 4)
129 break;
130 if (*p == 0) {
131 for (; i < 4; i++) {
132 pos[i] = p;
133 len[i] = 0;
134 }
135 break;
136 }
137 p++;
138 }
139
140 /* Copy the entries in reverse order */
141 p = out;
142 leading = 1;
143 for (i = 3; i >= 0; i--) {
144 memcpy(p, pos[i], len[i]);
145 if (len[i])
146 leading = 0;
147 p += len[i];
148 /* Need a . separator? */
149 if (!leading && i > 0 && len[i - 1])
150 *p++ = '.';
151 }
152 *p = '\0';
153 }
154
155 static int
getnetanswer(querybuf * answer,int anslen,int net_i,struct netent * ne,struct netent_data * ned,res_state statp)156 getnetanswer(querybuf *answer, int anslen, int net_i, struct netent *ne,
157 struct netent_data *ned, res_state statp)
158 {
159
160 HEADER *hp;
161 u_char *cp;
162 int n;
163 u_char *eom;
164 int type, class, ancount, qdcount, haveanswer;
165 char aux[MAXHOSTNAMELEN];
166 char ans[MAXHOSTNAMELEN];
167 char *in, *bp, *ep, **ap;
168
169 /*
170 * find first satisfactory answer
171 *
172 * answer --> +------------+ ( MESSAGE )
173 * | Header |
174 * +------------+
175 * | Question | the question for the name server
176 * +------------+
177 * | Answer | RRs answering the question
178 * +------------+
179 * | Authority | RRs pointing toward an authority
180 * | Additional | RRs holding additional information
181 * +------------+
182 */
183 eom = answer->buf + anslen;
184 hp = &answer->hdr;
185 ancount = ntohs(hp->ancount); /* #/records in the answer section */
186 qdcount = ntohs(hp->qdcount); /* #/entries in the question section */
187 bp = ned->netbuf;
188 ep = ned->netbuf + sizeof(ned->netbuf);
189 cp = answer->buf + HFIXEDSZ;
190 if (!qdcount) {
191 if (hp->aa)
192 RES_SET_H_ERRNO(statp, HOST_NOT_FOUND);
193 else
194 RES_SET_H_ERRNO(statp, TRY_AGAIN);
195 return (-1);
196 }
197 while (qdcount-- > 0)
198 cp += __dn_skipname(cp, eom) + QFIXEDSZ;
199 ap = ned->net_aliases;
200 *ap = NULL;
201 ne->n_aliases = ned->net_aliases;
202 haveanswer = 0;
203 while (--ancount >= 0 && cp < eom) {
204 n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
205 if ((n < 0) || !res_dnok(bp))
206 break;
207 cp += n;
208 ans[0] = '\0';
209 (void)strncpy(&ans[0], bp, sizeof(ans) - 1);
210 ans[sizeof(ans) - 1] = '\0';
211 GETSHORT(type, cp);
212 GETSHORT(class, cp);
213 cp += INT32SZ; /* TTL */
214 GETSHORT(n, cp);
215 if (class == C_IN && type == T_PTR) {
216 n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
217 if ((n < 0) || !res_hnok(bp)) {
218 cp += n;
219 return (-1);
220 }
221 cp += n;
222 *ap++ = bp;
223 n = strlen(bp) + 1;
224 bp += n;
225 ne->n_addrtype = (class == C_IN) ? AF_INET : AF_UNSPEC;
226 haveanswer++;
227 }
228 }
229 if (haveanswer) {
230 *ap = NULL;
231 switch (net_i) {
232 case BYADDR:
233 ne->n_name = *ne->n_aliases;
234 ne->n_net = 0L;
235 break;
236 case BYNAME:
237 in = *ne->n_aliases;
238 n = strlen(ans) + 1;
239 if (ep - bp < n) {
240 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
241 errno = ENOBUFS;
242 return (-1);
243 }
244 strlcpy(bp, ans, ep - bp);
245 ne->n_name = bp;
246 if (strlen(in) + 1 > sizeof(aux)) {
247 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
248 errno = ENOBUFS;
249 return (-1);
250 }
251 ipreverse(in, aux);
252 ne->n_net = inet_network(aux);
253 break;
254 }
255 ne->n_aliases++;
256 return (0);
257 }
258 RES_SET_H_ERRNO(statp, TRY_AGAIN);
259 return (-1);
260 }
261
262 int
_dns_getnetbyaddr(void * rval,void * cb_data,va_list ap)263 _dns_getnetbyaddr(void *rval, void *cb_data, va_list ap)
264 {
265 uint32_t net;
266 int net_type;
267 char *buffer;
268 size_t buflen;
269 int *errnop, *h_errnop;
270 struct netent *nptr, ne;
271 struct netent_data *ned;
272 unsigned int netbr[4];
273 int nn, anslen, error;
274 querybuf *buf;
275 char qbuf[MAXDNAME];
276 uint32_t net2;
277 res_state statp;
278
279 net = va_arg(ap, uint32_t);
280 net_type = va_arg(ap, int);
281 nptr = va_arg(ap, struct netent *);
282 buffer = va_arg(ap, char *);
283 buflen = va_arg(ap, size_t);
284 errnop = va_arg(ap, int *);
285 h_errnop = va_arg(ap, int *);
286
287 statp = __res_state();
288 if ((statp->options & RES_INIT) == 0 && res_ninit(statp) == -1) {
289 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
290 *h_errnop = statp->res_h_errno;
291 return (NS_UNAVAIL);
292 }
293
294 if ((ned = __netent_data_init()) == NULL) {
295 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
296 *h_errnop = statp->res_h_errno;
297 return (NS_UNAVAIL);
298 }
299
300 *((struct netent **)rval) = NULL;
301
302 if (net_type != AF_INET) {
303 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
304 *h_errnop = statp->res_h_errno;
305 return (NS_UNAVAIL);
306 }
307
308 for (nn = 4, net2 = net; net2; net2 >>= 8)
309 netbr[--nn] = net2 & 0xff;
310 switch (nn) {
311 case 3: /* Class A */
312 sprintf(qbuf, "0.0.0.%u.in-addr.arpa", netbr[3]);
313 break;
314 case 2: /* Class B */
315 sprintf(qbuf, "0.0.%u.%u.in-addr.arpa", netbr[3], netbr[2]);
316 break;
317 case 1: /* Class C */
318 sprintf(qbuf, "0.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2],
319 netbr[1]);
320 break;
321 case 0: /* Class D - E */
322 sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2],
323 netbr[1], netbr[0]);
324 break;
325 }
326 if ((buf = malloc(sizeof(*buf))) == NULL) {
327 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
328 *h_errnop = statp->res_h_errno;
329 return (NS_NOTFOUND);
330 }
331 anslen = res_nquery(statp, qbuf, C_IN, T_PTR, (u_char *)buf,
332 sizeof(*buf));
333 if (anslen < 0) {
334 free(buf);
335 #ifdef DEBUG
336 if (statp->options & RES_DEBUG)
337 printf("res_nsearch failed\n");
338 #endif
339 *h_errnop = statp->res_h_errno;
340 return (NS_UNAVAIL);
341 } else if (anslen > sizeof(*buf)) {
342 free(buf);
343 #ifdef DEBUG
344 if (statp->options & RES_DEBUG)
345 printf("res_nsearch static buffer too small\n");
346 #endif
347 *h_errnop = statp->res_h_errno;
348 return (NS_UNAVAIL);
349 }
350 error = getnetanswer(buf, anslen, BYADDR, &ne, ned, statp);
351 free(buf);
352 if (error == 0) {
353 /* Strip trailing zeros */
354 while ((net & 0xff) == 0 && net != 0)
355 net >>= 8;
356 ne.n_net = net;
357 if (__copy_netent(&ne, nptr, buffer, buflen) != 0) {
358 *errnop = errno;
359 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
360 *h_errnop = statp->res_h_errno;
361 return (NS_RETURN);
362 }
363 *((struct netent **)rval) = nptr;
364 return (NS_SUCCESS);
365 }
366 *h_errnop = statp->res_h_errno;
367 return (NS_NOTFOUND);
368 }
369
370 int
_dns_getnetbyname(void * rval,void * cb_data,va_list ap)371 _dns_getnetbyname(void *rval, void *cb_data, va_list ap)
372 {
373 const char *net;
374 char *buffer;
375 size_t buflen;
376 int *errnop, *h_errnop;
377 struct netent *nptr, ne;
378 struct netent_data *ned;
379 int anslen, error;
380 querybuf *buf;
381 char qbuf[MAXDNAME];
382 res_state statp;
383
384 net = va_arg(ap, const char *);
385 nptr = va_arg(ap, struct netent *);
386 buffer = va_arg(ap, char *);
387 buflen = va_arg(ap, size_t);
388 errnop = va_arg(ap, int *);
389 h_errnop = va_arg(ap, int *);
390
391 statp = __res_state();
392 if ((statp->options & RES_INIT) == 0 && res_ninit(statp) == -1) {
393 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
394 *h_errnop = statp->res_h_errno;
395 return (NS_UNAVAIL);
396 }
397 if ((ned = __netent_data_init()) == NULL) {
398 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
399 *h_errnop = statp->res_h_errno;
400 return (NS_UNAVAIL);
401 }
402 if ((buf = malloc(sizeof(*buf))) == NULL) {
403 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
404 *h_errnop = statp->res_h_errno;
405 return (NS_NOTFOUND);
406 }
407
408 *((struct netent **)rval) = NULL;
409
410 strncpy(qbuf, net, sizeof(qbuf) - 1);
411 qbuf[sizeof(qbuf) - 1] = '\0';
412 anslen = res_nsearch(statp, qbuf, C_IN, T_PTR, (u_char *)buf,
413 sizeof(*buf));
414 if (anslen < 0) {
415 free(buf);
416 #ifdef DEBUG
417 if (statp->options & RES_DEBUG)
418 printf("res_nsearch failed\n");
419 #endif
420 return (NS_UNAVAIL);
421 } else if (anslen > sizeof(*buf)) {
422 free(buf);
423 #ifdef DEBUG
424 if (statp->options & RES_DEBUG)
425 printf("res_search static buffer too small\n");
426 #endif
427 return (NS_UNAVAIL);
428 }
429 error = getnetanswer(buf, anslen, BYNAME, &ne, ned, statp);
430 free(buf);
431 if (error != 0) {
432 *h_errnop = statp->res_h_errno;
433 return (NS_NOTFOUND);
434 }
435 if (__copy_netent(&ne, nptr, buffer, buflen) != 0) {
436 *errnop = errno;
437 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
438 *h_errnop = statp->res_h_errno;
439 return (NS_RETURN);
440 }
441 *((struct netent **)rval) = nptr;
442 return (NS_SUCCESS);
443 }
444
445 void
_setnetdnsent(int stayopen)446 _setnetdnsent(int stayopen)
447 {
448 res_state statp;
449
450 statp = __res_state();
451 if ((statp->options & RES_INIT) == 0 && res_ninit(statp) == -1)
452 return;
453 if (stayopen)
454 statp->options |= RES_STAYOPEN | RES_USEVC;
455 }
456
457 void
_endnetdnsent(void)458 _endnetdnsent(void)
459 {
460 res_state statp;
461
462 statp = __res_state();
463 statp->options &= ~(RES_STAYOPEN | RES_USEVC);
464 res_nclose(statp);
465 }
466