1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1985, 1988, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 * -
31 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
32 *
33 * Permission to use, copy, modify, and distribute this software for any
34 * purpose with or without fee is hereby granted, provided that the above
35 * copyright notice and this permission notice appear in all copies, and that
36 * the name of Digital Equipment Corporation not be used in advertising or
37 * publicity pertaining to distribution of the document or software without
38 * specific, written prior permission.
39 *
40 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
41 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
42 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
43 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
44 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
45 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
46 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
47 * SOFTWARE.
48 * -
49 * --Copyright--
50 */
51 /* Portions Copyright (c) 1993 Carlos Leandro and Rui Salgueiro
52 * Dep. Matematica Universidade de Coimbra, Portugal, Europe
53 *
54 * Permission to use, copy, modify, and distribute this software for any
55 * purpose with or without fee is hereby granted, provided that the above
56 * copyright notice and this permission notice appear in all copies.
57 */
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
65 #include <errno.h>
66 #include <stdio.h>
67 #include <stdlib.h>
68 #include <netdb.h>
69 #include <resolv.h>
70 #include <ctype.h>
71 #include <string.h>
72 #include <unistd.h>
73 #include <syslog.h>
74 #include <stdarg.h>
75 #include <nsswitch.h>
76
77 #include "netdb_private.h"
78 #include "res_config.h"
79
80 #define BYADDR 0
81 #define BYNAME 1
82
83 #define MAXPACKET (64*1024)
84
85 typedef union {
86 HEADER hdr;
87 u_char buf[MAXPACKET];
88 } querybuf;
89
90 typedef union {
91 long al;
92 char ac;
93 } align;
94
95 /*
96 * Reverse the order of first four dotted entries of in.
97 * Out must contain space for at least strlen(in) characters.
98 * The result does not include any leading 0s of in.
99 */
100 static void
ipreverse(char * in,char * out)101 ipreverse(char *in, char *out)
102 {
103 char *pos[4];
104 int len[4];
105 char *p, *start;
106 int i = 0;
107 int leading = 1;
108
109 /* Fill-in element positions and lengths: pos[], len[]. */
110 start = p = in;
111 for (;;) {
112 if (*p == '.' || *p == '\0') {
113 /* Leading 0? */
114 if (leading && p - start == 1 && *start == '0')
115 len[i] = 0;
116 else {
117 len[i] = p - start;
118 leading = 0;
119 }
120 pos[i] = start;
121 start = p + 1;
122 i++;
123 }
124 if (i == 4)
125 break;
126 if (*p == 0) {
127 for (; i < 4; i++) {
128 pos[i] = p;
129 len[i] = 0;
130 }
131 break;
132 }
133 p++;
134 }
135
136 /* Copy the entries in reverse order */
137 p = out;
138 leading = 1;
139 for (i = 3; i >= 0; i--) {
140 memcpy(p, pos[i], len[i]);
141 if (len[i])
142 leading = 0;
143 p += len[i];
144 /* Need a . separator? */
145 if (!leading && i > 0 && len[i - 1])
146 *p++ = '.';
147 }
148 *p = '\0';
149 }
150
151 static int
getnetanswer(querybuf * answer,int anslen,int net_i,struct netent * ne,struct netent_data * ned,res_state statp)152 getnetanswer(querybuf *answer, int anslen, int net_i, struct netent *ne,
153 struct netent_data *ned, res_state statp)
154 {
155
156 HEADER *hp;
157 u_char *cp;
158 int n;
159 u_char *eom;
160 int type, class, ancount, qdcount, haveanswer;
161 char aux[MAXHOSTNAMELEN];
162 char ans[MAXHOSTNAMELEN];
163 char *in, *bp, *ep, **ap;
164
165 /*
166 * find first satisfactory answer
167 *
168 * answer --> +------------+ ( MESSAGE )
169 * | Header |
170 * +------------+
171 * | Question | the question for the name server
172 * +------------+
173 * | Answer | RRs answering the question
174 * +------------+
175 * | Authority | RRs pointing toward an authority
176 * | Additional | RRs holding additional information
177 * +------------+
178 */
179 eom = answer->buf + anslen;
180 hp = &answer->hdr;
181 ancount = ntohs(hp->ancount); /* #/records in the answer section */
182 qdcount = ntohs(hp->qdcount); /* #/entries in the question section */
183 bp = ned->netbuf;
184 ep = ned->netbuf + sizeof(ned->netbuf);
185 cp = answer->buf + HFIXEDSZ;
186 if (!qdcount) {
187 if (hp->aa)
188 RES_SET_H_ERRNO(statp, HOST_NOT_FOUND);
189 else
190 RES_SET_H_ERRNO(statp, TRY_AGAIN);
191 return (-1);
192 }
193 while (qdcount-- > 0)
194 cp += __dn_skipname(cp, eom) + QFIXEDSZ;
195 ap = ned->net_aliases;
196 *ap = NULL;
197 ne->n_aliases = ned->net_aliases;
198 haveanswer = 0;
199 while (--ancount >= 0 && cp < eom) {
200 n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
201 if ((n < 0) || !res_dnok(bp))
202 break;
203 cp += n;
204 ans[0] = '\0';
205 (void)strncpy(&ans[0], bp, sizeof(ans) - 1);
206 ans[sizeof(ans) - 1] = '\0';
207 GETSHORT(type, cp);
208 GETSHORT(class, cp);
209 cp += INT32SZ; /* TTL */
210 GETSHORT(n, cp);
211 if (class == C_IN && type == T_PTR) {
212 n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
213 if ((n < 0) || !res_hnok(bp)) {
214 cp += n;
215 return (-1);
216 }
217 cp += n;
218 *ap++ = bp;
219 n = strlen(bp) + 1;
220 bp += n;
221 ne->n_addrtype = (class == C_IN) ? AF_INET : AF_UNSPEC;
222 haveanswer++;
223 }
224 }
225 if (haveanswer) {
226 *ap = NULL;
227 switch (net_i) {
228 case BYADDR:
229 ne->n_name = *ne->n_aliases;
230 ne->n_net = 0L;
231 break;
232 case BYNAME:
233 in = *ne->n_aliases;
234 n = strlen(ans) + 1;
235 if (ep - bp < n) {
236 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
237 errno = ENOBUFS;
238 return (-1);
239 }
240 strlcpy(bp, ans, ep - bp);
241 ne->n_name = bp;
242 if (strlen(in) + 1 > sizeof(aux)) {
243 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
244 errno = ENOBUFS;
245 return (-1);
246 }
247 ipreverse(in, aux);
248 ne->n_net = inet_network(aux);
249 break;
250 }
251 ne->n_aliases++;
252 return (0);
253 }
254 RES_SET_H_ERRNO(statp, TRY_AGAIN);
255 return (-1);
256 }
257
258 int
_dns_getnetbyaddr(void * rval,void * cb_data,va_list ap)259 _dns_getnetbyaddr(void *rval, void *cb_data, va_list ap)
260 {
261 uint32_t net;
262 int net_type;
263 char *buffer;
264 size_t buflen;
265 int *errnop, *h_errnop;
266 struct netent *nptr, ne;
267 struct netent_data *ned;
268 unsigned int netbr[4];
269 int nn, anslen, error;
270 querybuf *buf;
271 char qbuf[MAXDNAME];
272 uint32_t net2;
273 res_state statp;
274
275 net = va_arg(ap, uint32_t);
276 net_type = va_arg(ap, int);
277 nptr = va_arg(ap, struct netent *);
278 buffer = va_arg(ap, char *);
279 buflen = va_arg(ap, size_t);
280 errnop = va_arg(ap, int *);
281 h_errnop = va_arg(ap, int *);
282
283 statp = __res_state();
284 if ((statp->options & RES_INIT) == 0 && res_ninit(statp) == -1) {
285 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
286 *h_errnop = statp->res_h_errno;
287 return (NS_UNAVAIL);
288 }
289
290 if ((ned = __netent_data_init()) == NULL) {
291 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
292 *h_errnop = statp->res_h_errno;
293 return (NS_UNAVAIL);
294 }
295
296 *((struct netent **)rval) = NULL;
297
298 if (net_type != AF_INET) {
299 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
300 *h_errnop = statp->res_h_errno;
301 return (NS_UNAVAIL);
302 }
303
304 for (nn = 4, net2 = net; net2; net2 >>= 8)
305 netbr[--nn] = net2 & 0xff;
306 switch (nn) {
307 case 3: /* Class A */
308 sprintf(qbuf, "0.0.0.%u.in-addr.arpa", netbr[3]);
309 break;
310 case 2: /* Class B */
311 sprintf(qbuf, "0.0.%u.%u.in-addr.arpa", netbr[3], netbr[2]);
312 break;
313 case 1: /* Class C */
314 sprintf(qbuf, "0.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2],
315 netbr[1]);
316 break;
317 case 0: /* Class D - E */
318 sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2],
319 netbr[1], netbr[0]);
320 break;
321 }
322 if ((buf = malloc(sizeof(*buf))) == NULL) {
323 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
324 *h_errnop = statp->res_h_errno;
325 return (NS_NOTFOUND);
326 }
327 anslen = res_nquery(statp, qbuf, C_IN, T_PTR, (u_char *)buf,
328 sizeof(*buf));
329 if (anslen < 0) {
330 free(buf);
331 #ifdef DEBUG
332 if (statp->options & RES_DEBUG)
333 printf("res_nsearch failed\n");
334 #endif
335 *h_errnop = statp->res_h_errno;
336 return (NS_UNAVAIL);
337 } else if (anslen > sizeof(*buf)) {
338 free(buf);
339 #ifdef DEBUG
340 if (statp->options & RES_DEBUG)
341 printf("res_nsearch static buffer too small\n");
342 #endif
343 *h_errnop = statp->res_h_errno;
344 return (NS_UNAVAIL);
345 }
346 error = getnetanswer(buf, anslen, BYADDR, &ne, ned, statp);
347 free(buf);
348 if (error == 0) {
349 /* Strip trailing zeros */
350 while ((net & 0xff) == 0 && net != 0)
351 net >>= 8;
352 ne.n_net = net;
353 if (__copy_netent(&ne, nptr, buffer, buflen) != 0) {
354 *errnop = errno;
355 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
356 *h_errnop = statp->res_h_errno;
357 return (NS_RETURN);
358 }
359 *((struct netent **)rval) = nptr;
360 return (NS_SUCCESS);
361 }
362 *h_errnop = statp->res_h_errno;
363 return (NS_NOTFOUND);
364 }
365
366 int
_dns_getnetbyname(void * rval,void * cb_data,va_list ap)367 _dns_getnetbyname(void *rval, void *cb_data, va_list ap)
368 {
369 const char *net;
370 char *buffer;
371 size_t buflen;
372 int *errnop, *h_errnop;
373 struct netent *nptr, ne;
374 struct netent_data *ned;
375 int anslen, error;
376 querybuf *buf;
377 char qbuf[MAXDNAME];
378 res_state statp;
379
380 net = va_arg(ap, const char *);
381 nptr = va_arg(ap, struct netent *);
382 buffer = va_arg(ap, char *);
383 buflen = va_arg(ap, size_t);
384 errnop = va_arg(ap, int *);
385 h_errnop = va_arg(ap, int *);
386
387 statp = __res_state();
388 if ((statp->options & RES_INIT) == 0 && res_ninit(statp) == -1) {
389 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
390 *h_errnop = statp->res_h_errno;
391 return (NS_UNAVAIL);
392 }
393 if ((ned = __netent_data_init()) == NULL) {
394 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
395 *h_errnop = statp->res_h_errno;
396 return (NS_UNAVAIL);
397 }
398 if ((buf = malloc(sizeof(*buf))) == NULL) {
399 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
400 *h_errnop = statp->res_h_errno;
401 return (NS_NOTFOUND);
402 }
403
404 *((struct netent **)rval) = NULL;
405
406 strncpy(qbuf, net, sizeof(qbuf) - 1);
407 qbuf[sizeof(qbuf) - 1] = '\0';
408 anslen = res_nsearch(statp, qbuf, C_IN, T_PTR, (u_char *)buf,
409 sizeof(*buf));
410 if (anslen < 0) {
411 free(buf);
412 #ifdef DEBUG
413 if (statp->options & RES_DEBUG)
414 printf("res_nsearch failed\n");
415 #endif
416 return (NS_UNAVAIL);
417 } else if (anslen > sizeof(*buf)) {
418 free(buf);
419 #ifdef DEBUG
420 if (statp->options & RES_DEBUG)
421 printf("res_search static buffer too small\n");
422 #endif
423 return (NS_UNAVAIL);
424 }
425 error = getnetanswer(buf, anslen, BYNAME, &ne, ned, statp);
426 free(buf);
427 if (error != 0) {
428 *h_errnop = statp->res_h_errno;
429 return (NS_NOTFOUND);
430 }
431 if (__copy_netent(&ne, nptr, buffer, buflen) != 0) {
432 *errnop = errno;
433 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
434 *h_errnop = statp->res_h_errno;
435 return (NS_RETURN);
436 }
437 *((struct netent **)rval) = nptr;
438 return (NS_SUCCESS);
439 }
440
441 void
_setnetdnsent(int stayopen)442 _setnetdnsent(int stayopen)
443 {
444 res_state statp;
445
446 statp = __res_state();
447 if ((statp->options & RES_INIT) == 0 && res_ninit(statp) == -1)
448 return;
449 if (stayopen)
450 statp->options |= RES_STAYOPEN | RES_USEVC;
451 }
452
453 void
_endnetdnsent(void)454 _endnetdnsent(void)
455 {
456 res_state statp;
457
458 statp = __res_state();
459 statp->options &= ~(RES_STAYOPEN | RES_USEVC);
460 res_nclose(statp);
461 }
462