contrib/bind-9.2.4rc7/lib/bind/irs/dns_nw.c

   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 1.3.2.7 2004/05/17 07:46:42 marka 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);
 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 }