lib/libc/net/getnetbydns.c

   1 /*-
   2  * Copyright (c) 1985, 1988, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  * -
  29  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
  30  *
  31  * Permission to use, copy, modify, and distribute this software for any
  32  * purpose with or without fee is hereby granted, provided that the above
  33  * copyright notice and this permission notice appear in all copies, and that
  34  * the name of Digital Equipment Corporation not be used in advertising or
  35  * publicity pertaining to distribution of the document or software without
  36  * specific, written prior permission.
  37  *
  38  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
  39  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
  40  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
  41  * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  42  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  43  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  44  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  45  * SOFTWARE.
  46  * -
  47  * --Copyright--
  48  *
  49  * @(#)gethostnamadr.c  8.1 (Berkeley) 6/4/93
  50  * $FreeBSD: src/lib/libc/net/getnetbydns.c,v 1.34 2007/01/09 00:28:02 imp Exp $
  51  */
  52 /* Portions Copyright (c) 1993 Carlos Leandro and Rui Salgueiro
  53  *      Dep. Matematica Universidade de Coimbra, Portugal, Europe
  54  *
  55  * Permission to use, copy, modify, and distribute this software for any
  56  * purpose with or without fee is hereby granted, provided that the above
  57  * copyright notice and this permission notice appear in all copies.
  58  */
  59
  60 #include <sys/param.h>
  61 #include <sys/socket.h>
  62 #include <netinet/in.h>
  63 #include <arpa/inet.h>
  64 #include <arpa/nameser.h>
  65
  66 #include <errno.h>
  67 #include <stdio.h>
  68 #include <stdlib.h>
  69 #include <netdb.h>
  70 #include <resolv.h>
  71 #include <ctype.h>
  72 #include <string.h>
  73 #include <unistd.h>
  74 #include <syslog.h>
  75 #include <stdarg.h>
  76 #include <nsswitch.h>
  77
  78 #include "netdb_private.h"
  79 #include "res_config.h"
  80
  81 #define BYADDR 0
  82 #define BYNAME 1
  83
  84 #define MAXPACKET       (64*1024)
  85
  86 typedef union {
  87         HEADER  hdr;
  88         u_char  buf[MAXPACKET];
  89 } querybuf;
  90
  91 typedef union {
  92         long    al;
  93         char    ac;
  94 } align;
  95
  96 /*
  97  * Reverse the order of first four dotted entries of in.
  98  * Out must contain space for at least strlen(in) characters.
  99  * The result does not include any leading 0s of in.
 100  */
 101 static void
 102 ipreverse(char *in, char *out)
 103 {
 104         char *pos[4];
 105         int len[4];
 106         char *p, *start;
 107         int i = 0;
 108         int leading = 1;
 109
 110         /* Fill-in element positions and lengths: pos[], len[]. */
 111         start = p = in;
 112         for (;;) {
 113                 if (*p == '.' || *p == '\0') {
 114                         /* Leading 0? */
 115                         if (leading && p - start == 1 && *start == '0')
 116                                 len[i] = 0;
 117                         else {
 118                                 len[i] = p - start;
 119                                 leading = 0;
 120                         }
 121                         pos[i] = start;
 122                         start = p + 1;
 123                         i++;
 124                 }
 125                 if (i == 4)
 126                         break;
 127                 if (*p == 0) {
 128                         for (; i < 4; i++) {
 129                                 pos[i] = p;
 130                                 len[i] = 0;
 131                         }
 132                         break;
 133                 }
 134                 p++;
 135         }
 136
 137         /* Copy the entries in reverse order */
 138         p = out;
 139         leading = 1;
 140         for (i = 3; i >= 0; i--) {
 141                 memcpy(p, pos[i], len[i]);
 142                 if (len[i])
 143                         leading = 0;
 144                 p += len[i];
 145                 /* Need a . separator? */
 146                 if (!leading && i > 0 && len[i - 1])
 147                         *p++ = '.';
 148         }
 149         *p = '\0';
 150 }
 151
 152 static int
 153 getnetanswer(querybuf *answer, int anslen, int net_i, struct netent *ne,
 154              struct netent_data *ned, res_state statp)
 155 {
 156
 157         HEADER *hp;
 158         u_char *cp;
 159         int n;
 160         u_char *eom;
 161         int type, class, ancount, qdcount, haveanswer;
 162         char aux[MAXHOSTNAMELEN];
 163         char ans[MAXHOSTNAMELEN];
 164         char *in, *bp, *ep, **ap;
 165
 166         /*
 167          * find first satisfactory answer
 168          *
 169          *      answer --> +------------+  ( MESSAGE )
 170          *                 |   Header   |
 171          *                 +------------+
 172          *                 |  Question  | the question for the name server
 173          *                 +------------+
 174          *                 |   Answer   | RRs answering the question
 175          *                 +------------+
 176          *                 | Authority  | RRs pointing toward an authority
 177          *                 | Additional | RRs holding additional information
 178          *                 +------------+
 179          */
 180         eom = answer->buf + anslen;
 181         hp = &answer->hdr;
 182         ancount = ntohs(hp->ancount); /* #/records in the answer section */
 183         qdcount = ntohs(hp->qdcount); /* #/entries in the question section */
 184         bp = ned->netbuf;
 185         ep = ned->netbuf + sizeof(ned->netbuf);
 186         cp = answer->buf + HFIXEDSZ;
 187         if (!qdcount) {
 188                 if (hp->aa)
 189                         RES_SET_H_ERRNO(statp, HOST_NOT_FOUND);
 190                 else
 191                         RES_SET_H_ERRNO(statp, TRY_AGAIN);
 192                 return (-1);
 193         }
 194         while (qdcount-- > 0)
 195                 cp += __dn_skipname(cp, eom) + QFIXEDSZ;
 196         ap = ned->net_aliases;
 197         *ap = NULL;
 198         ne->n_aliases = ned->net_aliases;
 199         haveanswer = 0;
 200         while (--ancount >= 0 && cp < eom) {
 201                 n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
 202                 if ((n < 0) || !res_dnok(bp))
 203                         break;
 204                 cp += n;
 205                 ans[0] = '\0';
 206                 strncpy(&ans[0], bp, sizeof(ans) - 1);
 207                 ans[sizeof(ans) - 1] = '\0';
 208                 GETSHORT(type, cp);
 209                 GETSHORT(class, cp);
 210                 cp += INT32SZ;          /* TTL */
 211                 GETSHORT(n, cp);
 212                 if (class == C_IN && type == T_PTR) {
 213                         n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
 214                         if ((n < 0) || !res_hnok(bp)) {
 215                                 cp += n;
 216                                 return (-1);
 217                         }
 218                         cp += n;
 219                         *ap++ = bp;
 220                         n = strlen(bp) + 1;
 221                         bp += n;
 222                         ne->n_addrtype = (class == C_IN) ? AF_INET : AF_UNSPEC;
 223                         haveanswer++;
 224                 }
 225         }
 226         if (haveanswer) {
 227                 *ap = NULL;
 228                 switch (net_i) {
 229                 case BYADDR:
 230                         ne->n_name = *ne->n_aliases;
 231                         ne->n_net = 0L;
 232                         break;
 233                 case BYNAME:
 234                         in = *ne->n_aliases;
 235                         n = strlen(ans) + 1;
 236                         if (ep - bp < n) {
 237                                 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
 238                                 errno = ENOBUFS;
 239                                 return (-1);
 240                         }
 241                         strlcpy(bp, ans, ep - bp);
 242                         ne->n_name = bp;
 243                         if (strlen(in) + 1 > sizeof(aux)) {
 244                                 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
 245                                 errno = ENOBUFS;
 246                                 return (-1);
 247                         }
 248                         ipreverse(in, aux);
 249                         ne->n_net = inet_network(aux);
 250                         break;
 251                 }
 252                 ne->n_aliases++;
 253                 return (0);
 254         }
 255         RES_SET_H_ERRNO(statp, TRY_AGAIN);
 256         return (-1);
 257 }
 258
 259 int
 260 _dns_getnetbyaddr(void *rval, void *cb_data __unused, va_list ap)
 261 {
 262         uint32_t net;
 263         int net_type;
 264         char *buffer;
 265         size_t buflen;
 266         int *errnop __unused;
 267         int *h_errnop;
 268         struct netent *nptr, ne;
 269         struct netent_data *ned;
 270         unsigned int netbr[4];
 271         int nn, anslen, error;
 272         querybuf *buf;
 273         char qbuf[MAXDNAME];
 274         uint32_t net2;
 275         res_state statp;
 276
 277         net = va_arg(ap, uint32_t);
 278         net_type = va_arg(ap, int);
 279         nptr = va_arg(ap, struct netent *);
 280         buffer = va_arg(ap, char *);
 281         buflen = va_arg(ap, size_t);
 282         errnop = va_arg(ap, int *);
 283         h_errnop = va_arg(ap, int *);
 284
 285         statp = __res_state();
 286         if ((statp->options & RES_INIT) == 0 && res_ninit(statp) == -1) {
 287                 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
 288                 *h_errnop = statp->res_h_errno;
 289                 return (NS_UNAVAIL);
 290         }
 291
 292         if ((ned = __netent_data_init()) == NULL) {
 293                 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
 294                 *h_errnop = statp->res_h_errno;
 295                 return (NS_UNAVAIL);
 296         }
 297
 298         *((struct netent **)rval) = NULL;
 299
 300         if (net_type != AF_INET) {
 301                 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
 302                 *h_errnop = statp->res_h_errno;
 303                 return (NS_UNAVAIL);
 304         }
 305
 306         for (nn = 4, net2 = net; net2; net2 >>= 8)
 307                 netbr[--nn] = net2 & 0xff;
 308         switch (nn) {
 309         case 3:         /* Class A */
 310                 sprintf(qbuf, "0.0.0.%u.in-addr.arpa", netbr[3]);
 311                 break;
 312         case 2:         /* Class B */
 313                 sprintf(qbuf, "0.0.%u.%u.in-addr.arpa", netbr[3], netbr[2]);
 314                 break;
 315         case 1:         /* Class C */
 316                 sprintf(qbuf, "0.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2],
 317                     netbr[1]);
 318                 break;
 319         case 0:         /* Class D - E */
 320                 sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2],
 321                     netbr[1], netbr[0]);
 322                 break;
 323         }
 324         if ((buf = malloc(sizeof(*buf))) == NULL) {
 325                 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
 326                 *h_errnop = statp->res_h_errno;
 327                 return (NS_NOTFOUND);
 328         }
 329         anslen = res_nquery(statp, qbuf, C_IN, T_PTR, (u_char *)buf,
 330             sizeof(*buf));
 331         if (anslen < 0) {
 332                 free(buf);
 333 #ifdef DEBUG
 334                 if (statp->options & RES_DEBUG)
 335                         printf("res_nsearch failed\n");
 336 #endif
 337                 *h_errnop = statp->res_h_errno;
 338                 return (NS_UNAVAIL);
 339         } else if (anslen > sizeof(*buf)) {
 340                 free(buf);
 341 #ifdef DEBUG
 342                 if (statp->options & RES_DEBUG)
 343                         printf("res_nsearch static buffer too small\n");
 344 #endif
 345                 *h_errnop = statp->res_h_errno;
 346                 return (NS_UNAVAIL);
 347         }
 348         error = getnetanswer(buf, anslen, BYADDR, &ne, ned, statp);
 349         free(buf);
 350         if (error == 0) {
 351                 /* Strip trailing zeros */
 352                 while ((net & 0xff) == 0 && net != 0)
 353                         net >>= 8;
 354                 ne.n_net = net;
 355                 if (__copy_netent(&ne, nptr, buffer, buflen) != 0) {
 356                         *h_errnop = statp->res_h_errno;
 357                         return (NS_NOTFOUND);
 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
 367 _dns_getnetbyname(void *rval, void *cb_data __unused, va_list ap)
 368 {
 369         const char *net;
 370         char *buffer;
 371         size_t buflen;
 372         int *errnop __unused;
 373         int *h_errnop;
 374         struct netent *nptr, ne;
 375         struct netent_data *ned;
 376         int anslen, error;
 377         querybuf *buf;
 378         char qbuf[MAXDNAME];
 379         res_state statp;
 380
 381         net = va_arg(ap, const char *);
 382         nptr = va_arg(ap, struct netent *);
 383         buffer = va_arg(ap, char *);
 384         buflen = va_arg(ap, size_t);
 385         errnop = va_arg(ap, int *);
 386         h_errnop = va_arg(ap, int *);
 387
 388         statp = __res_state();
 389         if ((statp->options & RES_INIT) == 0 && res_ninit(statp) == -1) {
 390                 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
 391                 *h_errnop = statp->res_h_errno;
 392                 return (NS_UNAVAIL);
 393         }
 394         if ((ned = __netent_data_init()) == NULL) {
 395                 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
 396                 *h_errnop = statp->res_h_errno;
 397                 return (NS_UNAVAIL);
 398         }
 399         if ((buf = malloc(sizeof(*buf))) == NULL) {
 400                 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
 401                 *h_errnop = statp->res_h_errno;
 402                 return (NS_NOTFOUND);
 403         }
 404
 405         *((struct netent **)rval) = NULL;
 406
 407         strncpy(qbuf, net, sizeof(qbuf) - 1);
 408         qbuf[sizeof(qbuf) - 1] = '\0';
 409         anslen = res_nsearch(statp, qbuf, C_IN, T_PTR, (u_char *)buf,
 410             sizeof(*buf));
 411         if (anslen < 0) {
 412                 free(buf);
 413 #ifdef DEBUG
 414                 if (statp->options & RES_DEBUG)
 415                         printf("res_nsearch failed\n");
 416 #endif
 417                 return (NS_UNAVAIL);
 418         } else if (anslen > sizeof(*buf)) {
 419                 free(buf);
 420 #ifdef DEBUG
 421                 if (statp->options & RES_DEBUG)
 422                         printf("res_search static buffer too small\n");
 423 #endif
 424                 return (NS_UNAVAIL);
 425         }
 426         error = getnetanswer(buf, anslen, BYNAME, &ne, ned, statp);
 427         free(buf);
 428         if (error != 0) {
 429                 *h_errnop = statp->res_h_errno;
 430                 return (NS_NOTFOUND);
 431         }
 432         if (__copy_netent(&ne, nptr, buffer, buflen) != 0) {
 433                 *h_errnop = statp->res_h_errno;
 434                 return (NS_NOTFOUND);
 435         }
 436         *((struct netent **)rval) = nptr;
 437         return (NS_SUCCESS);
 438 }
 439
 440 void
 441 _setnetdnsent(int stayopen)
 442 {
 443         res_state statp;
 444
 445         statp = __res_state();
 446         if ((statp->options & RES_INIT) == 0 && res_ninit(statp) == -1)
 447                 return;
 448         if (stayopen)
 449                 statp->options |= RES_STAYOPEN | RES_USEVC;
 450 }
 451
 452 void
 453 _endnetdnsent(void)
 454 {
 455         res_state statp;
 456
 457         statp = __res_state();
 458         statp->options &= ~(RES_STAYOPEN | RES_USEVC);
 459         res_nclose(statp);
 460 }