1 /*
2 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
3 * Copyright (c) 1996-1999 by Internet Software Consortium.
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
15 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18 /* Imports. */
19
20 #include "port_before.h"
21
22 #include <sys/param.h>
23 #include <sys/socket.h>
24
25 #include <netinet/in.h>
26 #include <arpa/inet.h>
27 #include <arpa/nameser.h>
28
29 #include <ctype.h>
30 #include <errno.h>
31 #include <netdb.h>
32 #include <resolv.h>
33 #include <stdio.h>
34 #include <stdlib.h>
35 #include <string.h>
36
37 #include <isc/memcluster.h>
38 #include <irs.h>
39
40 #include "port_after.h"
41
42 #include "irs_p.h"
43 #include "dns_p.h"
44
45 #ifdef SPRINTF_CHAR
46 # define SPRINTF(x) strlen(sprintf/**/x)
47 #else
48 # define SPRINTF(x) sprintf x
49 #endif
50
51 /* Definitions. */
52
53 #define MAXALIASES 35
54
55 #define MAXPACKET (64*1024)
56
57 struct pvt {
58 struct nwent net;
59 char * ali[MAXALIASES];
60 char buf[BUFSIZ+1];
61 struct __res_state * res;
62 void (*free_res)(void *);
63 };
64
65 typedef union {
66 long al;
67 char ac;
68 } align;
69
70 enum by_what { by_addr, by_name };
71
72 /* Forwards. */
73
74 static void nw_close(struct irs_nw *);
75 static struct nwent * nw_byname(struct irs_nw *, const char *, int);
76 static struct nwent * nw_byaddr(struct irs_nw *, void *, int, int);
77 static struct nwent * nw_next(struct irs_nw *);
78 static void nw_rewind(struct irs_nw *);
79 static void nw_minimize(struct irs_nw *);
80 static struct __res_state * nw_res_get(struct irs_nw *this);
81 static void nw_res_set(struct irs_nw *this,
82 struct __res_state *res,
83 void (*free_res)(void *));
84
85 static struct nwent * get1101byaddr(struct irs_nw *, u_char *, int);
86 static struct nwent * get1101byname(struct irs_nw *, const char *);
87 static struct nwent * get1101answer(struct irs_nw *,
88 u_char *ansbuf, int anslen,
89 enum by_what by_what,
90 int af, const char *name,
91 const u_char *addr, int addrlen);
92 static struct nwent * get1101mask(struct irs_nw *this, struct nwent *);
93 static int make1101inaddr(const u_char *, int, char *, int);
94 static void normalize_name(char *name);
95 static int init(struct irs_nw *this);
96
97 /* Exports. */
98
99 struct irs_nw *
irs_dns_nw(struct irs_acc * this)100 irs_dns_nw(struct irs_acc *this) {
101 struct irs_nw *nw;
102 struct pvt *pvt;
103
104 UNUSED(this);
105
106 if (!(pvt = memget(sizeof *pvt))) {
107 errno = ENOMEM;
108 return (NULL);
109 }
110 memset(pvt, 0, sizeof *pvt);
111 if (!(nw = memget(sizeof *nw))) {
112 memput(pvt, sizeof *pvt);
113 errno = ENOMEM;
114 return (NULL);
115 }
116 memset(nw, 0x5e, sizeof *nw);
117 nw->private = pvt;
118 nw->close = nw_close;
119 nw->byname = nw_byname;
120 nw->byaddr = nw_byaddr;
121 nw->next = nw_next;
122 nw->rewind = nw_rewind;
123 nw->minimize = nw_minimize;
124 nw->res_get = nw_res_get;
125 nw->res_set = nw_res_set;
126 return (nw);
127 }
128
129 /* Methods. */
130
131 static void
nw_close(struct irs_nw * this)132 nw_close(struct irs_nw *this) {
133 struct pvt *pvt = (struct pvt *)this->private;
134
135 nw_minimize(this);
136
137 if (pvt->res && pvt->free_res)
138 (*pvt->free_res)(pvt->res);
139
140 memput(pvt, sizeof *pvt);
141 memput(this, sizeof *this);
142 }
143
144 static struct nwent *
nw_byname(struct irs_nw * this,const char * name,int af)145 nw_byname(struct irs_nw *this, const char *name, int af) {
146 struct pvt *pvt = (struct pvt *)this->private;
147
148 if (init(this) == -1)
149 return (NULL);
150
151 switch (af) {
152 case AF_INET:
153 return (get1101byname(this, name));
154 default:
155 (void)NULL;
156 }
157 RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL);
158 errno = EAFNOSUPPORT;
159 return (NULL);
160 }
161
162 static struct nwent *
nw_byaddr(struct irs_nw * this,void * net,int len,int af)163 nw_byaddr(struct irs_nw *this, void *net, int len, int af) {
164 struct pvt *pvt = (struct pvt *)this->private;
165
166 if (init(this) == -1)
167 return (NULL);
168
169 switch (af) {
170 case AF_INET:
171 return (get1101byaddr(this, net, len));
172 default:
173 (void)NULL;
174 }
175 RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL);
176 errno = EAFNOSUPPORT;
177 return (NULL);
178 }
179
180 static struct nwent *
nw_next(struct irs_nw * this)181 nw_next(struct irs_nw *this) {
182
183 UNUSED(this);
184
185 return (NULL);
186 }
187
188 static void
nw_rewind(struct irs_nw * this)189 nw_rewind(struct irs_nw *this) {
190 UNUSED(this);
191 /* NOOP */
192 }
193
194 static void
nw_minimize(struct irs_nw * this)195 nw_minimize(struct irs_nw *this) {
196 struct pvt *pvt = (struct pvt *)this->private;
197
198 if (pvt->res)
199 res_nclose(pvt->res);
200 }
201
202 static struct __res_state *
nw_res_get(struct irs_nw * this)203 nw_res_get(struct irs_nw *this) {
204 struct pvt *pvt = (struct pvt *)this->private;
205
206 if (!pvt->res) {
207 struct __res_state *res;
208 res = (struct __res_state *)malloc(sizeof *res);
209 if (!res) {
210 errno = ENOMEM;
211 return (NULL);
212 }
213 memset(res, 0, sizeof *res);
214 nw_res_set(this, res, free);
215 }
216
217 return (pvt->res);
218 }
219
220 static void
nw_res_set(struct irs_nw * this,struct __res_state * res,void (* free_res)(void *))221 nw_res_set(struct irs_nw *this, struct __res_state *res,
222 void (*free_res)(void *)) {
223 struct pvt *pvt = (struct pvt *)this->private;
224
225 if (pvt->res && pvt->free_res) {
226 res_nclose(pvt->res);
227 (*pvt->free_res)(pvt->res);
228 }
229
230 pvt->res = res;
231 pvt->free_res = free_res;
232 }
233
234 /* Private. */
235
236 static struct nwent *
get1101byname(struct irs_nw * this,const char * name)237 get1101byname(struct irs_nw *this, const char *name) {
238 struct pvt *pvt = (struct pvt *)this->private;
239 u_char *ansbuf;
240 int anslen;
241 struct nwent *result;
242
243 ansbuf = memget(MAXPACKET);
244 if (ansbuf == NULL) {
245 errno = ENOMEM;
246 RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL);
247 return (NULL);
248 }
249 anslen = res_nsearch(pvt->res, name, C_IN, T_PTR, ansbuf, MAXPACKET);
250 if (anslen < 0) {
251 memput(ansbuf, MAXPACKET);
252 return (NULL);
253 }
254 result = get1101mask(this, get1101answer(this, ansbuf, anslen, by_name,
255 AF_INET, name, NULL, 0));
256 memput(ansbuf, MAXPACKET);
257 return (result);
258 }
259
260 static struct nwent *
get1101byaddr(struct irs_nw * this,u_char * net,int len)261 get1101byaddr(struct irs_nw *this, u_char *net, int len) {
262 struct pvt *pvt = (struct pvt *)this->private;
263 char qbuf[sizeof "255.255.255.255.in-addr.arpa"];
264 struct nwent *result;
265 u_char *ansbuf;
266 int anslen;
267
268 if (len < 1 || len > 32) {
269 errno = EINVAL;
270 RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL);
271 return (NULL);
272 }
273 if (make1101inaddr(net, len, qbuf, sizeof qbuf) < 0)
274 return (NULL);
275 ansbuf = memget(MAXPACKET);
276 if (ansbuf == NULL) {
277 errno = ENOMEM;
278 RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL);
279 return (NULL);
280 }
281 anslen = res_nquery(pvt->res, qbuf, C_IN, T_PTR, ansbuf, MAXPACKET);
282 if (anslen < 0) {
283 memput(ansbuf, MAXPACKET);
284 return (NULL);
285 }
286 result = get1101mask(this, get1101answer(this, ansbuf, anslen, by_addr,
287 AF_INET, NULL, net, len));
288 memput(ansbuf, MAXPACKET);
289 return (result);
290 }
291
292 static struct nwent *
get1101answer(struct irs_nw * this,u_char * ansbuf,int anslen,enum by_what by_what,int af,const char * name,const u_char * addr,int addrlen)293 get1101answer(struct irs_nw *this,
294 u_char *ansbuf, int anslen, enum by_what by_what,
295 int af, const char *name, const u_char *addr, int addrlen)
296 {
297 struct pvt *pvt = (struct pvt *)this->private;
298 int type, class, ancount, qdcount, haveanswer;
299 char *bp, *ep, **ap;
300 u_char *cp, *eom;
301 HEADER *hp;
302
303 /* Initialize, and parse header. */
304 eom = ansbuf + anslen;
305 if (ansbuf + HFIXEDSZ > eom) {
306 RES_SET_H_ERRNO(pvt->res, NO_RECOVERY);
307 return (NULL);
308 }
309 hp = (HEADER *)ansbuf;
310 cp = ansbuf + HFIXEDSZ;
311 qdcount = ntohs(hp->qdcount);
312 while (qdcount-- > 0) {
313 int n = dn_skipname(cp, eom);
314 cp += n + QFIXEDSZ;
315 if (n < 0 || cp > eom) {
316 RES_SET_H_ERRNO(pvt->res, NO_RECOVERY);
317 return (NULL);
318 }
319 }
320 ancount = ntohs(hp->ancount);
321 if (!ancount) {
322 if (hp->aa)
323 RES_SET_H_ERRNO(pvt->res, HOST_NOT_FOUND);
324 else
325 RES_SET_H_ERRNO(pvt->res, TRY_AGAIN);
326 return (NULL);
327 }
328
329 /* Prepare a return structure. */
330 bp = pvt->buf;
331 ep = pvt->buf + sizeof(pvt->buf);
332 pvt->net.n_name = NULL;
333 pvt->net.n_aliases = pvt->ali;
334 pvt->net.n_addrtype = af;
335 pvt->net.n_addr = NULL;
336 pvt->net.n_length = addrlen;
337
338 /* Save input key if given. */
339 switch (by_what) {
340 case by_name:
341 if (name != NULL) {
342 int n = strlen(name) + 1;
343
344 if (n > (ep - bp)) {
345 RES_SET_H_ERRNO(pvt->res, NO_RECOVERY);
346 return (NULL);
347 }
348 pvt->net.n_name = strcpy(bp, name); /* (checked) */
349 bp += n;
350 }
351 break;
352 case by_addr:
353 if (addr != NULL && addrlen != 0) {
354 int n = addrlen / 8 + ((addrlen % 8) != 0);
355
356 if (INADDRSZ > (ep - bp)) {
357 RES_SET_H_ERRNO(pvt->res, NO_RECOVERY);
358 return (NULL);
359 }
360 memset(bp, 0, INADDRSZ);
361 memcpy(bp, addr, n);
362 pvt->net.n_addr = bp;
363 bp += INADDRSZ;
364 }
365 break;
366 default:
367 abort();
368 }
369
370 /* Parse the answer, collect aliases. */
371 ap = pvt->ali;
372 haveanswer = 0;
373 while (--ancount >= 0 && cp < eom) {
374 int n = dn_expand(ansbuf, eom, cp, bp, ep - bp);
375
376 cp += n; /*%< Owner */
377 if (n < 0 || !maybe_dnok(pvt->res, bp) ||
378 cp + 3 * INT16SZ + INT32SZ > eom) {
379 RES_SET_H_ERRNO(pvt->res, NO_RECOVERY);
380 return (NULL);
381 }
382 GETSHORT(type, cp); /*%< Type */
383 GETSHORT(class, cp); /*%< Class */
384 cp += INT32SZ; /*%< TTL */
385 GETSHORT(n, cp); /*%< RDLENGTH */
386 if (class == C_IN && type == T_PTR) {
387 int nn;
388
389 nn = dn_expand(ansbuf, eom, cp, bp, ep - bp);
390 if (nn < 0 || !maybe_hnok(pvt->res, bp) || nn != n) {
391 RES_SET_H_ERRNO(pvt->res, NO_RECOVERY);
392 return (NULL);
393 }
394 normalize_name(bp);
395 switch (by_what) {
396 case by_addr: {
397 if (pvt->net.n_name == NULL)
398 pvt->net.n_name = bp;
399 else if (ns_samename(pvt->net.n_name, bp) == 1)
400 break;
401 else
402 *ap++ = bp;
403 nn = strlen(bp) + 1;
404 bp += nn;
405 haveanswer++;
406 break;
407 }
408 case by_name: {
409 u_int b1, b2, b3, b4;
410
411 if (pvt->net.n_addr != NULL ||
412 sscanf(bp, "%u.%u.%u.%u.in-addr.arpa",
413 &b1, &b2, &b3, &b4) != 4)
414 break;
415 if ((ep - bp) < INADDRSZ) {
416 RES_SET_H_ERRNO(pvt->res, NO_RECOVERY);
417 return (NULL);
418 }
419 pvt->net.n_addr = bp;
420 *bp++ = b4;
421 *bp++ = b3;
422 *bp++ = b2;
423 *bp++ = b1;
424 pvt->net.n_length = INADDRSZ * 8;
425 haveanswer++;
426 }
427 }
428 }
429 cp += n; /*%< RDATA */
430 }
431 if (!haveanswer) {
432 RES_SET_H_ERRNO(pvt->res, TRY_AGAIN);
433 return (NULL);
434 }
435 *ap = NULL;
436
437 return (&pvt->net);
438 }
439
440 static struct nwent *
get1101mask(struct irs_nw * this,struct nwent * nwent)441 get1101mask(struct irs_nw *this, struct nwent *nwent) {
442 struct pvt *pvt = (struct pvt *)this->private;
443 char qbuf[sizeof "255.255.255.255.in-addr.arpa"], owner[MAXDNAME];
444 int anslen, type, class, ancount, qdcount;
445 u_char *ansbuf, *cp, *eom;
446 HEADER *hp;
447
448 if (!nwent)
449 return (NULL);
450 if (make1101inaddr(nwent->n_addr, nwent->n_length, qbuf, sizeof qbuf)
451 < 0) {
452 /* "First, do no harm." */
453 return (nwent);
454 }
455
456 ansbuf = memget(MAXPACKET);
457 if (ansbuf == NULL) {
458 errno = ENOMEM;
459 RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL);
460 return (NULL);
461 }
462 /* Query for the A RR that would hold this network's mask. */
463 anslen = res_nquery(pvt->res, qbuf, C_IN, T_A, ansbuf, MAXPACKET);
464 if (anslen < HFIXEDSZ) {
465 memput(ansbuf, MAXPACKET);
466 return (nwent);
467 }
468
469 /* Initialize, and parse header. */
470 hp = (HEADER *)ansbuf;
471 cp = ansbuf + HFIXEDSZ;
472 eom = ansbuf + anslen;
473 qdcount = ntohs(hp->qdcount);
474 while (qdcount-- > 0) {
475 int n = dn_skipname(cp, eom);
476 cp += n + QFIXEDSZ;
477 if (n < 0 || cp > eom) {
478 memput(ansbuf, MAXPACKET);
479 return (nwent);
480 }
481 }
482 ancount = ntohs(hp->ancount);
483
484 /* Parse the answer, collect aliases. */
485 while (--ancount >= 0 && cp < eom) {
486 int n = dn_expand(ansbuf, eom, cp, owner, sizeof owner);
487
488 if (n < 0 || !maybe_dnok(pvt->res, owner))
489 break;
490 cp += n; /*%< Owner */
491 if (cp + 3 * INT16SZ + INT32SZ > eom)
492 break;
493 GETSHORT(type, cp); /*%< Type */
494 GETSHORT(class, cp); /*%< Class */
495 cp += INT32SZ; /*%< TTL */
496 GETSHORT(n, cp); /*%< RDLENGTH */
497 if (cp + n > eom)
498 break;
499 if (n == INADDRSZ && class == C_IN && type == T_A &&
500 ns_samename(qbuf, owner) == 1) {
501 /* This A RR indicates the actual netmask. */
502 int nn, mm;
503
504 nwent->n_length = 0;
505 for (nn = 0; nn < INADDRSZ; nn++)
506 for (mm = 7; mm >= 0; mm--)
507 if (cp[nn] & (1 << mm))
508 nwent->n_length++;
509 else
510 break;
511 }
512 cp += n; /*%< RDATA */
513 }
514 memput(ansbuf, MAXPACKET);
515 return (nwent);
516 }
517
518 static int
make1101inaddr(const u_char * net,int bits,char * name,int size)519 make1101inaddr(const u_char *net, int bits, char *name, int size) {
520 int n, m;
521 char *ep;
522
523 ep = name + size;
524
525 /* Zero fill any whole bytes left out of the prefix. */
526 for (n = (32 - bits) / 8; n > 0; n--) {
527 if (ep - name < (int)(sizeof "0."))
528 goto emsgsize;
529 m = SPRINTF((name, "0."));
530 name += m;
531 }
532
533 /* Format the partial byte, if any, within the prefix. */
534 if ((n = bits % 8) != 0) {
535 if (ep - name < (int)(sizeof "255."))
536 goto emsgsize;
537 m = SPRINTF((name, "%u.",
538 net[bits / 8] & ~((1 << (8 - n)) - 1)));
539 name += m;
540 }
541
542 /* Format the whole bytes within the prefix. */
543 for (n = bits / 8; n > 0; n--) {
544 if (ep - name < (int)(sizeof "255."))
545 goto emsgsize;
546 m = SPRINTF((name, "%u.", net[n - 1]));
547 name += m;
548 }
549
550 /* Add the static text. */
551 if (ep - name < (int)(sizeof "in-addr.arpa"))
552 goto emsgsize;
553 (void) SPRINTF((name, "in-addr.arpa"));
554 return (0);
555
556 emsgsize:
557 errno = EMSGSIZE;
558 return (-1);
559 }
560
561 static void
normalize_name(char * name)562 normalize_name(char *name) {
563 char *t;
564
565 /* Make lower case. */
566 for (t = name; *t; t++)
567 if (isascii((unsigned char)*t) && isupper((unsigned char)*t))
568 *t = tolower((*t)&0xff);
569
570 /* Remove trailing dots. */
571 while (t > name && t[-1] == '.')
572 *--t = '\0';
573 }
574
575 static int
init(struct irs_nw * this)576 init(struct irs_nw *this) {
577 struct pvt *pvt = (struct pvt *)this->private;
578
579 if (!pvt->res && !nw_res_get(this))
580 return (-1);
581 if (((pvt->res->options & RES_INIT) == 0U) &&
582 res_ninit(pvt->res) == -1)
583 return (-1);
584 return (0);
585 }
586
587 /*! \file */
588