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 #if defined(LIBC_SCCS) && !defined(lint) 19 static const char rcsid[] = "$Id: dns_nw.c,v 1.12 2005/04/27 04:56:22 sra Exp $"; 20 #endif /* LIBC_SCCS and not lint */ 21 22 /* Imports. */ 23 24 #include "port_before.h" 25 26 #include <sys/param.h> 27 #include <sys/socket.h> 28 29 #include <netinet/in.h> 30 #include <arpa/inet.h> 31 #include <arpa/nameser.h> 32 33 #include <ctype.h> 34 #include <errno.h> 35 #include <netdb.h> 36 #include <resolv.h> 37 #include <stdio.h> 38 #include <stdlib.h> 39 #include <string.h> 40 41 #include <isc/memcluster.h> 42 #include <irs.h> 43 44 #include "port_after.h" 45 46 #include "irs_p.h" 47 #include "dns_p.h" 48 49 #ifdef SPRINTF_CHAR 50 # define SPRINTF(x) strlen(sprintf/**/x) 51 #else 52 # define SPRINTF(x) sprintf x 53 #endif 54 55 /* Definitions. */ 56 57 #define MAXALIASES 35 58 59 #define MAXPACKET (64*1024) 60 61 struct pvt { 62 struct nwent net; 63 char * ali[MAXALIASES]; 64 char buf[BUFSIZ+1]; 65 struct __res_state * res; 66 void (*free_res)(void *); 67 }; 68 69 typedef union { 70 long al; 71 char ac; 72 } align; 73 74 enum by_what { by_addr, by_name }; 75 76 /* Forwards. */ 77 78 static void nw_close(struct irs_nw *); 79 static struct nwent * nw_byname(struct irs_nw *, const char *, int); 80 static struct nwent * nw_byaddr(struct irs_nw *, void *, int, int); 81 static struct nwent * nw_next(struct irs_nw *); 82 static void nw_rewind(struct irs_nw *); 83 static void nw_minimize(struct irs_nw *); 84 static struct __res_state * nw_res_get(struct irs_nw *this); 85 static void nw_res_set(struct irs_nw *this, 86 struct __res_state *res, 87 void (*free_res)(void *)); 88 89 static struct nwent * get1101byaddr(struct irs_nw *, u_char *, int); 90 static struct nwent * get1101byname(struct irs_nw *, const char *); 91 static struct nwent * get1101answer(struct irs_nw *, 92 u_char *ansbuf, int anslen, 93 enum by_what by_what, 94 int af, const char *name, 95 const u_char *addr, int addrlen); 96 static struct nwent * get1101mask(struct irs_nw *this, struct nwent *); 97 static int make1101inaddr(const u_char *, int, char *, int); 98 static void normalize_name(char *name); 99 static int init(struct irs_nw *this); 100 101 /* Exports. */ 102 103 struct irs_nw * 104 irs_dns_nw(struct irs_acc *this) { 105 struct irs_nw *nw; 106 struct pvt *pvt; 107 108 UNUSED(this); 109 110 if (!(pvt = memget(sizeof *pvt))) { 111 errno = ENOMEM; 112 return (NULL); 113 } 114 memset(pvt, 0, sizeof *pvt); 115 if (!(nw = memget(sizeof *nw))) { 116 memput(pvt, sizeof *pvt); 117 errno = ENOMEM; 118 return (NULL); 119 } 120 memset(nw, 0x5e, sizeof *nw); 121 nw->private = pvt; 122 nw->close = nw_close; 123 nw->byname = nw_byname; 124 nw->byaddr = nw_byaddr; 125 nw->next = nw_next; 126 nw->rewind = nw_rewind; 127 nw->minimize = nw_minimize; 128 nw->res_get = nw_res_get; 129 nw->res_set = nw_res_set; 130 return (nw); 131 } 132 133 /* Methods. */ 134 135 static void 136 nw_close(struct irs_nw *this) { 137 struct pvt *pvt = (struct pvt *)this->private; 138 139 nw_minimize(this); 140 141 if (pvt->res && pvt->free_res) 142 (*pvt->free_res)(pvt->res); 143 144 memput(pvt, sizeof *pvt); 145 memput(this, sizeof *this); 146 } 147 148 static struct nwent * 149 nw_byname(struct irs_nw *this, const char *name, int af) { 150 struct pvt *pvt = (struct pvt *)this->private; 151 152 if (init(this) == -1) 153 return (NULL); 154 155 switch (af) { 156 case AF_INET: 157 return (get1101byname(this, name)); 158 default: 159 (void)NULL; 160 } 161 RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL); 162 errno = EAFNOSUPPORT; 163 return (NULL); 164 } 165 166 static struct nwent * 167 nw_byaddr(struct irs_nw *this, void *net, int len, int af) { 168 struct pvt *pvt = (struct pvt *)this->private; 169 170 if (init(this) == -1) 171 return (NULL); 172 173 switch (af) { 174 case AF_INET: 175 return (get1101byaddr(this, net, len)); 176 default: 177 (void)NULL; 178 } 179 RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL); 180 errno = EAFNOSUPPORT; 181 return (NULL); 182 } 183 184 static struct nwent * 185 nw_next(struct irs_nw *this) { 186 187 UNUSED(this); 188 189 return (NULL); 190 } 191 192 static void 193 nw_rewind(struct irs_nw *this) { 194 UNUSED(this); 195 /* NOOP */ 196 } 197 198 static void 199 nw_minimize(struct irs_nw *this) { 200 struct pvt *pvt = (struct pvt *)this->private; 201 202 if (pvt->res) 203 res_nclose(pvt->res); 204 } 205 206 static struct __res_state * 207 nw_res_get(struct irs_nw *this) { 208 struct pvt *pvt = (struct pvt *)this->private; 209 210 if (!pvt->res) { 211 struct __res_state *res; 212 res = (struct __res_state *)malloc(sizeof *res); 213 if (!res) { 214 errno = ENOMEM; 215 return (NULL); 216 } 217 memset(res, 0, sizeof *res); 218 nw_res_set(this, res, free); 219 } 220 221 return (pvt->res); 222 } 223 224 static void 225 nw_res_set(struct irs_nw *this, struct __res_state *res, 226 void (*free_res)(void *)) { 227 struct pvt *pvt = (struct pvt *)this->private; 228 229 if (pvt->res && pvt->free_res) { 230 res_nclose(pvt->res); 231 (*pvt->free_res)(pvt->res); 232 } 233 234 pvt->res = res; 235 pvt->free_res = free_res; 236 } 237 238 /* Private. */ 239 240 static struct nwent * 241 get1101byname(struct irs_nw *this, const char *name) { 242 struct pvt *pvt = (struct pvt *)this->private; 243 u_char *ansbuf; 244 int anslen; 245 struct nwent *result; 246 247 ansbuf = memget(MAXPACKET); 248 if (ansbuf == NULL) { 249 errno = ENOMEM; 250 RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL); 251 return (NULL); 252 } 253 anslen = res_nsearch(pvt->res, name, C_IN, T_PTR, ansbuf, MAXPACKET); 254 if (anslen < 0) { 255 memput(ansbuf, MAXPACKET); 256 return (NULL); 257 } 258 result = get1101mask(this, get1101answer(this, ansbuf, anslen, by_name, 259 AF_INET, name, NULL, 0)); 260 memput(ansbuf, MAXPACKET); 261 return (result); 262 } 263 264 static struct nwent * 265 get1101byaddr(struct irs_nw *this, u_char *net, int len) { 266 struct pvt *pvt = (struct pvt *)this->private; 267 char qbuf[sizeof "255.255.255.255.in-addr.arpa"]; 268 struct nwent *result; 269 u_char *ansbuf; 270 int anslen; 271 272 if (len < 1 || len > 32) { 273 errno = EINVAL; 274 RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL); 275 return (NULL); 276 } 277 if (make1101inaddr(net, len, qbuf, sizeof qbuf) < 0) 278 return (NULL); 279 ansbuf = memget(MAXPACKET); 280 if (ansbuf == NULL) { 281 errno = ENOMEM; 282 RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL); 283 return (NULL); 284 } 285 anslen = res_nquery(pvt->res, qbuf, C_IN, T_PTR, ansbuf, MAXPACKET); 286 if (anslen < 0) { 287 memput(ansbuf, MAXPACKET); 288 return (NULL); 289 } 290 result = get1101mask(this, get1101answer(this, ansbuf, anslen, by_addr, 291 AF_INET, NULL, net, len)); 292 memput(ansbuf, MAXPACKET); 293 return (result); 294 } 295 296 static struct nwent * 297 get1101answer(struct irs_nw *this, 298 u_char *ansbuf, int anslen, enum by_what by_what, 299 int af, const char *name, const u_char *addr, int addrlen) 300 { 301 struct pvt *pvt = (struct pvt *)this->private; 302 int type, class, ancount, qdcount, haveanswer; 303 char *bp, *ep, **ap; 304 u_char *cp, *eom; 305 HEADER *hp; 306 307 /* Initialize, and parse header. */ 308 eom = ansbuf + anslen; 309 if (ansbuf + HFIXEDSZ > eom) { 310 RES_SET_H_ERRNO(pvt->res, NO_RECOVERY); 311 return (NULL); 312 } 313 hp = (HEADER *)ansbuf; 314 cp = ansbuf + HFIXEDSZ; 315 qdcount = ntohs(hp->qdcount); 316 while (qdcount-- > 0) { 317 int n = dn_skipname(cp, eom); 318 cp += n + QFIXEDSZ; 319 if (n < 0 || cp > eom) { 320 RES_SET_H_ERRNO(pvt->res, NO_RECOVERY); 321 return (NULL); 322 } 323 } 324 ancount = ntohs(hp->ancount); 325 if (!ancount) { 326 if (hp->aa) 327 RES_SET_H_ERRNO(pvt->res, HOST_NOT_FOUND); 328 else 329 RES_SET_H_ERRNO(pvt->res, TRY_AGAIN); 330 return (NULL); 331 } 332 333 /* Prepare a return structure. */ 334 bp = pvt->buf; 335 ep = pvt->buf + sizeof(pvt->buf); 336 pvt->net.n_name = NULL; 337 pvt->net.n_aliases = pvt->ali; 338 pvt->net.n_addrtype = af; 339 pvt->net.n_addr = NULL; 340 pvt->net.n_length = addrlen; 341 342 /* Save input key if given. */ 343 switch (by_what) { 344 case by_name: 345 if (name != NULL) { 346 int n = strlen(name) + 1; 347 348 if (n > (ep - bp)) { 349 RES_SET_H_ERRNO(pvt->res, NO_RECOVERY); 350 return (NULL); 351 } 352 pvt->net.n_name = strcpy(bp, name); /* (checked) */ 353 bp += n; 354 } 355 break; 356 case by_addr: 357 if (addr != NULL && addrlen != 0) { 358 int n = addrlen / 8 + ((addrlen % 8) != 0); 359 360 if (INADDRSZ > (ep - bp)) { 361 RES_SET_H_ERRNO(pvt->res, NO_RECOVERY); 362 return (NULL); 363 } 364 memset(bp, 0, INADDRSZ); 365 memcpy(bp, addr, n); 366 pvt->net.n_addr = bp; 367 bp += INADDRSZ; 368 } 369 break; 370 default: 371 abort(); 372 } 373 374 /* Parse the answer, collect aliases. */ 375 ap = pvt->ali; 376 haveanswer = 0; 377 while (--ancount >= 0 && cp < eom) { 378 int n = dn_expand(ansbuf, eom, cp, bp, ep - bp); 379 380 cp += n; /*%< Owner */ 381 if (n < 0 || !maybe_dnok(pvt->res, bp) || 382 cp + 3 * INT16SZ + INT32SZ > eom) { 383 RES_SET_H_ERRNO(pvt->res, NO_RECOVERY); 384 return (NULL); 385 } 386 GETSHORT(type, cp); /*%< Type */ 387 GETSHORT(class, cp); /*%< Class */ 388 cp += INT32SZ; /*%< TTL */ 389 GETSHORT(n, cp); /*%< RDLENGTH */ 390 if (class == C_IN && type == T_PTR) { 391 int nn; 392 393 nn = dn_expand(ansbuf, eom, cp, bp, ep - bp); 394 if (nn < 0 || !maybe_hnok(pvt->res, bp) || nn != n) { 395 RES_SET_H_ERRNO(pvt->res, NO_RECOVERY); 396 return (NULL); 397 } 398 normalize_name(bp); 399 switch (by_what) { 400 case by_addr: { 401 if (pvt->net.n_name == NULL) 402 pvt->net.n_name = bp; 403 else if (ns_samename(pvt->net.n_name, bp) == 1) 404 break; 405 else 406 *ap++ = bp; 407 nn = strlen(bp) + 1; 408 bp += nn; 409 haveanswer++; 410 break; 411 } 412 case by_name: { 413 u_int b1, b2, b3, b4; 414 415 if (pvt->net.n_addr != NULL || 416 sscanf(bp, "%u.%u.%u.%u.in-addr.arpa", 417 &b1, &b2, &b3, &b4) != 4) 418 break; 419 if ((ep - bp) < INADDRSZ) { 420 RES_SET_H_ERRNO(pvt->res, NO_RECOVERY); 421 return (NULL); 422 } 423 pvt->net.n_addr = bp; 424 *bp++ = b4; 425 *bp++ = b3; 426 *bp++ = b2; 427 *bp++ = b1; 428 pvt->net.n_length = INADDRSZ * 8; 429 haveanswer++; 430 } 431 } 432 } 433 cp += n; /*%< RDATA */ 434 } 435 if (!haveanswer) { 436 RES_SET_H_ERRNO(pvt->res, TRY_AGAIN); 437 return (NULL); 438 } 439 *ap = NULL; 440 441 return (&pvt->net); 442 } 443 444 static struct nwent * 445 get1101mask(struct irs_nw *this, struct nwent *nwent) { 446 struct pvt *pvt = (struct pvt *)this->private; 447 char qbuf[sizeof "255.255.255.255.in-addr.arpa"], owner[MAXDNAME]; 448 int anslen, type, class, ancount, qdcount; 449 u_char *ansbuf, *cp, *eom; 450 HEADER *hp; 451 452 if (!nwent) 453 return (NULL); 454 if (make1101inaddr(nwent->n_addr, nwent->n_length, qbuf, sizeof qbuf) 455 < 0) { 456 /* "First, do no harm." */ 457 return (nwent); 458 } 459 460 ansbuf = memget(MAXPACKET); 461 if (ansbuf == NULL) { 462 errno = ENOMEM; 463 RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL); 464 return (NULL); 465 } 466 /* Query for the A RR that would hold this network's mask. */ 467 anslen = res_nquery(pvt->res, qbuf, C_IN, T_A, ansbuf, MAXPACKET); 468 if (anslen < HFIXEDSZ) { 469 memput(ansbuf, MAXPACKET); 470 return (nwent); 471 } 472 473 /* Initialize, and parse header. */ 474 hp = (HEADER *)ansbuf; 475 cp = ansbuf + HFIXEDSZ; 476 eom = ansbuf + anslen; 477 qdcount = ntohs(hp->qdcount); 478 while (qdcount-- > 0) { 479 int n = dn_skipname(cp, eom); 480 cp += n + QFIXEDSZ; 481 if (n < 0 || cp > eom) { 482 memput(ansbuf, MAXPACKET); 483 return (nwent); 484 } 485 } 486 ancount = ntohs(hp->ancount); 487 488 /* Parse the answer, collect aliases. */ 489 while (--ancount >= 0 && cp < eom) { 490 int n = dn_expand(ansbuf, eom, cp, owner, sizeof owner); 491 492 if (n < 0 || !maybe_dnok(pvt->res, owner)) 493 break; 494 cp += n; /*%< Owner */ 495 if (cp + 3 * INT16SZ + INT32SZ > eom) 496 break; 497 GETSHORT(type, cp); /*%< Type */ 498 GETSHORT(class, cp); /*%< Class */ 499 cp += INT32SZ; /*%< TTL */ 500 GETSHORT(n, cp); /*%< RDLENGTH */ 501 if (cp + n > eom) 502 break; 503 if (n == INADDRSZ && class == C_IN && type == T_A && 504 ns_samename(qbuf, owner) == 1) { 505 /* This A RR indicates the actual netmask. */ 506 int nn, mm; 507 508 nwent->n_length = 0; 509 for (nn = 0; nn < INADDRSZ; nn++) 510 for (mm = 7; mm >= 0; mm--) 511 if (cp[nn] & (1 << mm)) 512 nwent->n_length++; 513 else 514 break; 515 } 516 cp += n; /*%< RDATA */ 517 } 518 memput(ansbuf, MAXPACKET); 519 return (nwent); 520 } 521 522 static int 523 make1101inaddr(const u_char *net, int bits, char *name, int size) { 524 int n, m; 525 char *ep; 526 527 ep = name + size; 528 529 /* Zero fill any whole bytes left out of the prefix. */ 530 for (n = (32 - bits) / 8; n > 0; n--) { 531 if (ep - name < (int)(sizeof "0.")) 532 goto emsgsize; 533 m = SPRINTF((name, "0.")); 534 name += m; 535 } 536 537 /* Format the partial byte, if any, within the prefix. */ 538 if ((n = bits % 8) != 0) { 539 if (ep - name < (int)(sizeof "255.")) 540 goto emsgsize; 541 m = SPRINTF((name, "%u.", 542 net[bits / 8] & ~((1 << (8 - n)) - 1))); 543 name += m; 544 } 545 546 /* Format the whole bytes within the prefix. */ 547 for (n = bits / 8; n > 0; n--) { 548 if (ep - name < (int)(sizeof "255.")) 549 goto emsgsize; 550 m = SPRINTF((name, "%u.", net[n - 1])); 551 name += m; 552 } 553 554 /* Add the static text. */ 555 if (ep - name < (int)(sizeof "in-addr.arpa")) 556 goto emsgsize; 557 (void) SPRINTF((name, "in-addr.arpa")); 558 return (0); 559 560 emsgsize: 561 errno = EMSGSIZE; 562 return (-1); 563 } 564 565 static void 566 normalize_name(char *name) { 567 char *t; 568 569 /* Make lower case. */ 570 for (t = name; *t; t++) 571 if (isascii((unsigned char)*t) && isupper((unsigned char)*t)) 572 *t = tolower((*t)&0xff); 573 574 /* Remove trailing dots. */ 575 while (t > name && t[-1] == '.') 576 *--t = '\0'; 577 } 578 579 static int 580 init(struct irs_nw *this) { 581 struct pvt *pvt = (struct pvt *)this->private; 582 583 if (!pvt->res && !nw_res_get(this)) 584 return (-1); 585 if (((pvt->res->options & RES_INIT) == 0U) && 586 res_ninit(pvt->res) == -1) 587 return (-1); 588 return (0); 589 } 590 591 /*! \file */ 592