1 /* 2 * Copyright 2003 Sun Microsystems, Inc. All rights reserved. 3 * Use is subject to license terms. 4 */ 5 6 /* 7 * Copyright (c) 1996-1999 by Internet Software Consortium. 8 * 9 * Permission to use, copy, modify, and distribute this software for any 10 * purpose with or without fee is hereby granted, provided that the above 11 * copyright notice and this permission notice appear in all copies. 12 * 13 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS 14 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES 15 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE 16 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL 17 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR 18 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS 19 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS 20 * SOFTWARE. 21 */ 22 23 #pragma ident "%Z%%M% %I% %E% SMI" 24 25 #if defined(LIBC_SCCS) && !defined(lint) 26 static const char rcsid[] = "$Id: dns_nw.c,v 1.25 2002/07/18 02:07:43 marka Exp $"; 27 #endif /* LIBC_SCCS and not lint */ 28 29 /* Imports. */ 30 31 #include "port_before.h" 32 33 #include <sys/param.h> 34 #include <sys/socket.h> 35 36 #include <netinet/in.h> 37 #include <arpa/inet.h> 38 #include <arpa/nameser.h> 39 40 #include <ctype.h> 41 #include <errno.h> 42 #include <netdb.h> 43 #include <resolv.h> 44 #include <stdio.h> 45 #include <stdlib.h> 46 #include <string.h> 47 48 #include <isc/memcluster.h> 49 #include <irs.h> 50 51 #include "port_after.h" 52 53 #include "irs_p.h" 54 #include "dns_p.h" 55 56 #ifdef SPRINTF_CHAR 57 # define SPRINTF(x) strlen(sprintf/**/x) 58 #else 59 # define SPRINTF(x) sprintf x 60 #endif 61 62 /* Definitions. */ 63 64 #define MAXALIASES 35 65 66 #define MAXPACKET (64*1024) 67 68 struct pvt { 69 struct nwent net; 70 char * ali[MAXALIASES]; 71 char buf[BUFSIZ+1]; 72 struct __res_state * res; 73 void (*free_res)(void *); 74 }; 75 76 typedef union { 77 long al; 78 char ac; 79 } align; 80 81 enum by_what { by_addr, by_name }; 82 83 /* Forwards. */ 84 85 static void nw_close(struct irs_nw *); 86 static struct nwent * nw_byname(struct irs_nw *, const char *, int); 87 static struct nwent * nw_byaddr(struct irs_nw *, void *, int, int); 88 static struct nwent * nw_next(struct irs_nw *); 89 static void nw_rewind(struct irs_nw *); 90 static void nw_minimize(struct irs_nw *); 91 static struct __res_state * nw_res_get(struct irs_nw *this); 92 static void nw_res_set(struct irs_nw *this, 93 struct __res_state *res, 94 void (*free_res)(void *)); 95 96 static struct nwent * get1101byaddr(struct irs_nw *, u_char *, int); 97 static struct nwent * get1101byname(struct irs_nw *, const char *); 98 static struct nwent * get1101answer(struct irs_nw *, 99 u_char *ansbuf, int anslen, 100 enum by_what by_what, 101 int af, const char *name, 102 const u_char *addr, int addrlen); 103 static struct nwent * get1101mask(struct irs_nw *this, struct nwent *); 104 static int make1101inaddr(const u_char *, int, char *, int); 105 static void normalize_name(char *name); 106 static int init(struct irs_nw *this); 107 108 /* Exports. */ 109 110 struct irs_nw * 111 irs_dns_nw(struct irs_acc *this) { 112 struct irs_nw *nw; 113 struct pvt *pvt; 114 115 UNUSED(this); 116 117 if (!(pvt = memget(sizeof *pvt))) { 118 errno = ENOMEM; 119 return (NULL); 120 } 121 memset(pvt, 0, sizeof *pvt); 122 if (!(nw = memget(sizeof *nw))) { 123 memput(pvt, sizeof *pvt); 124 errno = ENOMEM; 125 return (NULL); 126 } 127 memset(nw, 0x5e, sizeof *nw); 128 nw->private = pvt; 129 nw->close = nw_close; 130 nw->byname = nw_byname; 131 nw->byaddr = nw_byaddr; 132 nw->next = nw_next; 133 nw->rewind = nw_rewind; 134 nw->minimize = nw_minimize; 135 nw->res_get = nw_res_get; 136 nw->res_set = nw_res_set; 137 return (nw); 138 } 139 140 /* Methods. */ 141 142 static void 143 nw_close(struct irs_nw *this) { 144 struct pvt *pvt = (struct pvt *)this->private; 145 146 nw_minimize(this); 147 148 if (pvt->res && pvt->free_res) 149 (*pvt->free_res)(pvt->res); 150 151 memput(pvt, sizeof *pvt); 152 memput(this, sizeof *this); 153 } 154 155 static struct nwent * 156 nw_byname(struct irs_nw *this, const char *name, int af) { 157 struct pvt *pvt = (struct pvt *)this->private; 158 159 if (init(this) == -1) 160 return (NULL); 161 162 switch (af) { 163 case AF_INET: 164 return (get1101byname(this, name)); 165 default: 166 (void)NULL; 167 } 168 RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL); 169 errno = EAFNOSUPPORT; 170 return (NULL); 171 } 172 173 static struct nwent * 174 nw_byaddr(struct irs_nw *this, void *net, int len, int af) { 175 struct pvt *pvt = (struct pvt *)this->private; 176 177 if (init(this) == -1) 178 return (NULL); 179 180 switch (af) { 181 case AF_INET: 182 return (get1101byaddr(this, net, len)); 183 default: 184 (void)NULL; 185 } 186 RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL); 187 errno = EAFNOSUPPORT; 188 return (NULL); 189 } 190 191 static struct nwent * 192 nw_next(struct irs_nw *this) { 193 194 UNUSED(this); 195 196 return (NULL); 197 } 198 199 static void 200 nw_rewind(struct irs_nw *this) { 201 UNUSED(this); 202 /* NOOP */ 203 } 204 205 static void 206 nw_minimize(struct irs_nw *this) { 207 struct pvt *pvt = (struct pvt *)this->private; 208 209 if (pvt->res) 210 res_nclose(pvt->res); 211 } 212 213 static struct __res_state * 214 nw_res_get(struct irs_nw *this) { 215 struct pvt *pvt = (struct pvt *)this->private; 216 217 if (!pvt->res) { 218 struct __res_state *res; 219 res = (struct __res_state *)malloc(sizeof *res); 220 if (!res) { 221 errno = ENOMEM; 222 return (NULL); 223 } 224 memset(res, 0, sizeof *res); 225 nw_res_set(this, res, free); 226 } 227 228 return (pvt->res); 229 } 230 231 static void 232 nw_res_set(struct irs_nw *this, struct __res_state *res, 233 void (*free_res)(void *)) { 234 struct pvt *pvt = (struct pvt *)this->private; 235 236 if (pvt->res && pvt->free_res) { 237 res_nclose(pvt->res); 238 (*pvt->free_res)(pvt->res); 239 } 240 241 pvt->res = res; 242 pvt->free_res = free_res; 243 } 244 245 /* Private. */ 246 247 static struct nwent * 248 get1101byname(struct irs_nw *this, const char *name) { 249 struct pvt *pvt = (struct pvt *)this->private; 250 u_char *ansbuf; 251 int anslen; 252 struct nwent *result; 253 254 ansbuf = memget(MAXPACKET); 255 if (ansbuf == NULL) { 256 errno = ENOMEM; 257 RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL); 258 return (NULL); 259 } 260 anslen = res_nsearch(pvt->res, name, C_IN, T_PTR, ansbuf, MAXPACKET); 261 if (anslen < 0) { 262 memput(ansbuf, MAXPACKET); 263 return (NULL); 264 } 265 result = get1101mask(this, get1101answer(this, ansbuf, anslen, by_name, 266 AF_INET, name, NULL, 0)); 267 memput(ansbuf, MAXPACKET); 268 return (result); 269 } 270 271 static struct nwent * 272 get1101byaddr(struct irs_nw *this, u_char *net, int len) { 273 struct pvt *pvt = (struct pvt *)this->private; 274 char qbuf[sizeof "255.255.255.255.in-addr.arpa"]; 275 struct nwent *result; 276 u_char *ansbuf; 277 int anslen; 278 279 if (len < 1 || len > 32) { 280 errno = EINVAL; 281 RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL); 282 return (NULL); 283 } 284 if (make1101inaddr(net, len, qbuf, sizeof qbuf) < 0) 285 return (NULL); 286 ansbuf = memget(MAXPACKET); 287 if (ansbuf == NULL) { 288 errno = ENOMEM; 289 RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL); 290 return (NULL); 291 } 292 anslen = res_nquery(pvt->res, qbuf, C_IN, T_PTR, ansbuf, MAXPACKET); 293 if (anslen < 0) { 294 memput(ansbuf, MAXPACKET); 295 return (NULL); 296 } 297 result = get1101mask(this, get1101answer(this, ansbuf, anslen, by_addr, 298 AF_INET, NULL, net, len)); 299 memput(ansbuf, MAXPACKET); 300 return (result); 301 } 302 303 static struct nwent * 304 get1101answer(struct irs_nw *this, 305 u_char *ansbuf, int anslen, enum by_what by_what, 306 int af, const char *name, const u_char *addr, int addrlen) 307 { 308 struct pvt *pvt = (struct pvt *)this->private; 309 int type, class, ancount, qdcount, haveanswer; 310 char *bp, *ep, **ap; 311 u_char *cp, *eom; 312 HEADER *hp; 313 314 /* Initialize, and parse header. */ 315 eom = ansbuf + anslen; 316 if (ansbuf + HFIXEDSZ > eom) { 317 RES_SET_H_ERRNO(pvt->res, NO_RECOVERY); 318 return (NULL); 319 } 320 hp = (HEADER *)ansbuf; 321 cp = ansbuf + HFIXEDSZ; 322 qdcount = ntohs(hp->qdcount); 323 while (qdcount-- > 0) { 324 int n = dn_skipname(cp, eom); 325 cp += n + QFIXEDSZ; 326 if (n < 0 || cp > eom) { 327 RES_SET_H_ERRNO(pvt->res, NO_RECOVERY); 328 return (NULL); 329 } 330 } 331 ancount = ntohs(hp->ancount); 332 if (!ancount) { 333 if (hp->aa) 334 RES_SET_H_ERRNO(pvt->res, HOST_NOT_FOUND); 335 else 336 RES_SET_H_ERRNO(pvt->res, TRY_AGAIN); 337 return (NULL); 338 } 339 340 /* Prepare a return structure. */ 341 bp = pvt->buf; 342 ep = pvt->buf + sizeof (pvt->buf); 343 pvt->net.n_name = NULL; 344 pvt->net.n_aliases = pvt->ali; 345 pvt->net.n_addrtype = af; 346 pvt->net.n_addr = NULL; 347 pvt->net.n_length = addrlen; 348 349 /* Save input key if given. */ 350 switch (by_what) { 351 case by_name: 352 if (name != NULL) { 353 int n = strlen(name) + 1; 354 355 if (n > (ep - bp)) { 356 RES_SET_H_ERRNO(pvt->res, NO_RECOVERY); 357 return (NULL); 358 } 359 #ifdef HAVE_STRLCPY 360 strlcpy(bp, name, ep - bp); 361 pvt->net.n_name = bp; 362 #else 363 pvt->net.n_name = strcpy(bp, name); 364 #endif 365 bp += n; 366 } 367 break; 368 case by_addr: 369 if (addr != NULL && addrlen != 0) { 370 int n = addrlen / 8 + ((addrlen % 8) != 0); 371 372 if (INADDRSZ > (ep - bp)) { 373 RES_SET_H_ERRNO(pvt->res, NO_RECOVERY); 374 return (NULL); 375 } 376 memset(bp, 0, INADDRSZ); 377 memcpy(bp, addr, n); 378 pvt->net.n_addr = bp; 379 bp += INADDRSZ; 380 } 381 break; 382 default: 383 abort(); 384 } 385 386 /* Parse the answer, collect aliases. */ 387 ap = pvt->ali; 388 haveanswer = 0; 389 while (--ancount >= 0 && cp < eom) { 390 int n = dn_expand(ansbuf, eom, cp, bp, ep - bp); 391 392 cp += n; /* Owner */ 393 if (n < 0 || !maybe_dnok(pvt->res, bp) || 394 cp + 3 * INT16SZ + INT32SZ > eom) { 395 RES_SET_H_ERRNO(pvt->res, NO_RECOVERY); 396 return (NULL); 397 } 398 GETSHORT(type, cp); /* Type */ 399 GETSHORT(class, cp); /* Class */ 400 cp += INT32SZ; /* TTL */ 401 GETSHORT(n, cp); /* RDLENGTH */ 402 if (class == C_IN && type == T_PTR) { 403 int nn; 404 405 nn = dn_expand(ansbuf, eom, cp, bp, ep - bp); 406 if (nn < 0 || !maybe_hnok(pvt->res, bp) || nn != n) { 407 RES_SET_H_ERRNO(pvt->res, NO_RECOVERY); 408 return (NULL); 409 } 410 normalize_name(bp); 411 switch (by_what) { 412 case by_addr: { 413 if (pvt->net.n_name == NULL) 414 pvt->net.n_name = bp; 415 else if (ns_samename(pvt->net.n_name, bp) == 1) 416 break; 417 else 418 *ap++ = bp; 419 nn = strlen(bp) + 1; 420 bp += nn; 421 haveanswer++; 422 break; 423 } 424 case by_name: { 425 u_int b1, b2, b3, b4; 426 427 if (pvt->net.n_addr != NULL || 428 sscanf(bp, "%u.%u.%u.%u.in-addr.arpa", 429 &b1, &b2, &b3, &b4) != 4) 430 break; 431 if ((ep - bp) < INADDRSZ) { 432 RES_SET_H_ERRNO(pvt->res, NO_RECOVERY); 433 return (NULL); 434 } 435 pvt->net.n_addr = bp; 436 *bp++ = b4; 437 *bp++ = b3; 438 *bp++ = b2; 439 *bp++ = b1; 440 pvt->net.n_length = INADDRSZ * 8; 441 haveanswer++; 442 } 443 } 444 } 445 cp += n; /* RDATA */ 446 } 447 if (!haveanswer) { 448 RES_SET_H_ERRNO(pvt->res, TRY_AGAIN); 449 return (NULL); 450 } 451 *ap = NULL; 452 453 return (&pvt->net); 454 } 455 456 static struct nwent * 457 get1101mask(struct irs_nw *this, struct nwent *nwent) { 458 struct pvt *pvt = (struct pvt *)this->private; 459 char qbuf[sizeof "255.255.255.255.in-addr.arpa"], owner[MAXDNAME]; 460 int anslen, type, class, ancount, qdcount; 461 u_char *ansbuf, *cp, *eom; 462 HEADER *hp; 463 464 if (!nwent) 465 return (NULL); 466 if (make1101inaddr(nwent->n_addr, nwent->n_length, qbuf, sizeof qbuf) 467 < 0) { 468 /* "First, do no harm." */ 469 return (nwent); 470 } 471 472 ansbuf = memget(MAXPACKET); 473 if (ansbuf == NULL) { 474 errno = ENOMEM; 475 RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL); 476 return (NULL); 477 } 478 /* Query for the A RR that would hold this network's mask. */ 479 anslen = res_nquery(pvt->res, qbuf, C_IN, T_A, ansbuf, MAXPACKET); 480 if (anslen < HFIXEDSZ) { 481 memput(ansbuf, MAXPACKET); 482 return (nwent); 483 } 484 485 /* Initialize, and parse header. */ 486 hp = (HEADER *)ansbuf; 487 cp = ansbuf + HFIXEDSZ; 488 eom = ansbuf + anslen; 489 qdcount = ntohs(hp->qdcount); 490 while (qdcount-- > 0) { 491 int n = dn_skipname(cp, eom); 492 cp += n + QFIXEDSZ; 493 if (n < 0 || cp > eom) { 494 memput(ansbuf, MAXPACKET); 495 return (nwent); 496 } 497 } 498 ancount = ntohs(hp->ancount); 499 500 /* Parse the answer, collect aliases. */ 501 while (--ancount >= 0 && cp < eom) { 502 int n = dn_expand(ansbuf, eom, cp, owner, sizeof owner); 503 504 if (n < 0 || !maybe_dnok(pvt->res, owner)) 505 break; 506 cp += n; /* Owner */ 507 if (cp + 3 * INT16SZ + INT32SZ > eom) 508 break; 509 GETSHORT(type, cp); /* Type */ 510 GETSHORT(class, cp); /* Class */ 511 cp += INT32SZ; /* TTL */ 512 GETSHORT(n, cp); /* RDLENGTH */ 513 if (cp + n > eom) 514 break; 515 if (n == INADDRSZ && class == C_IN && type == T_A && 516 ns_samename(qbuf, owner) == 1) { 517 /* This A RR indicates the actual netmask. */ 518 int nn, mm; 519 520 nwent->n_length = 0; 521 for (nn = 0; nn < INADDRSZ; nn++) 522 for (mm = 7; mm >= 0; mm--) 523 if (cp[nn] & (1 << mm)) 524 nwent->n_length++; 525 else 526 break; 527 } 528 cp += n; /* RDATA */ 529 } 530 memput(ansbuf, MAXPACKET); 531 return (nwent); 532 } 533 534 static int 535 make1101inaddr(const u_char *net, int bits, char *name, int size) { 536 int n, m; 537 char *ep; 538 539 ep = name + size; 540 541 /* Zero fill any whole bytes left out of the prefix. */ 542 for (n = (32 - bits) / 8; n > 0; n--) { 543 if (ep - name < (int)(sizeof "0.")) 544 goto emsgsize; 545 m = SPRINTF((name, "0.")); 546 name += m; 547 } 548 549 /* Format the partial byte, if any, within the prefix. */ 550 if ((n = bits % 8) != 0) { 551 if (ep - name < (int)(sizeof "255.")) 552 goto emsgsize; 553 m = SPRINTF((name, "%u.", 554 net[bits / 8] & ~((1 << (8 - n)) - 1))); 555 name += m; 556 } 557 558 /* Format the whole bytes within the prefix. */ 559 for (n = bits / 8; n > 0; n--) { 560 if (ep - name < (int)(sizeof "255.")) 561 goto emsgsize; 562 m = SPRINTF((name, "%u.", net[n - 1])); 563 name += m; 564 } 565 566 /* Add the static text. */ 567 if (ep - name < (int)(sizeof "in-addr.arpa")) 568 goto emsgsize; 569 (void) SPRINTF((name, "in-addr.arpa")); 570 return (0); 571 572 emsgsize: 573 errno = EMSGSIZE; 574 return (-1); 575 } 576 577 static void 578 normalize_name(char *name) { 579 char *t; 580 581 /* Make lower case. */ 582 for (t = name; *t; t++) 583 if (isascii((unsigned char)*t) && isupper((unsigned char)*t)) 584 *t = tolower(*t); 585 586 /* Remove trailing dots. */ 587 while (t > name && t[-1] == '.') 588 *--t = '\0'; 589 } 590 591 static int 592 init(struct irs_nw *this) { 593 struct pvt *pvt = (struct pvt *)this->private; 594 595 if (!pvt->res && !nw_res_get(this)) 596 return (-1); 597 if (((pvt->res->options & RES_INIT) == 0) && 598 res_ninit(pvt->res) == -1) 599 return (-1); 600 return (0); 601 } 602