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  * 4. 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  * $DragonFly: src/lib/libc/net/getnetbydns.c,v 1.5 2005/11/13 02:04:47 swildner Exp $
  52  */
  53 /* Portions Copyright (c) 1993 Carlos Leandro and Rui Salgueiro
  54  *      Dep. Matematica Universidade de Coimbra, Portugal, Europe
  55  *
  56  * Permission to use, copy, modify, and distribute this software for any
  57  * purpose with or without fee is hereby granted, provided that the above
  58  * copyright notice and this permission notice appear in all copies.
  59  */
  60
  61 #include <sys/param.h>
  62 #include <sys/socket.h>
  63 #include <netinet/in.h>
  64 #include <arpa/inet.h>
  65 #include <arpa/nameser.h>
  66
  67 #include <errno.h>
  68 #include <stdio.h>
  69 #include <stdlib.h>
  70 #include <netdb.h>
  71 #include <resolv.h>
  72 #include <ctype.h>
  73 #include <string.h>
  74 #include <unistd.h>
  75 #include <syslog.h>
  76 #include <stdarg.h>
  77 #include <nsswitch.h>
  78
  79 #include "netdb_private.h"
  80 #include "res_config.h"
  81
  82 #define BYADDR 0
  83 #define BYNAME 1
  84
  85 #define MAXPACKET       (64*1024)
  86
  87 typedef union {
  88         HEADER  hdr;
  89         u_char  buf[MAXPACKET];
  90 } querybuf;
  91
  92 typedef union {
  93         long    al;
  94         char    ac;
  95 } align;
  96
  97 /*
  98  * Reverse the order of first four dotted entries of in.
  99  * Out must contain space for at least strlen(in) characters.
 100  * The result does not include any leading 0s of in.
 101  */
 102 static void
 103 ipreverse(char *in, char *out)
 104 {
 105         char *pos[4];
 106         int len[4];
 107         char *p, *start;
 108         int i = 0;
 109         int leading = 1;
 110
 111         /* Fill-in element positions and lengths: pos[], len[]. */
 112         start = p = in;
 113         for (;;) {
 114                 if (*p == '.' || *p == '\0') {
 115                         /* Leading 0? */
 116                         if (leading && p - start == 1 && *start == '0')
 117                                 len[i] = 0;
 118                         else {
 119                                 len[i] = p - start;
 120                                 leading = 0;
 121                         }
 122                         pos[i] = start;
 123                         start = p + 1;
 124                         i++;
 125                 }
 126                 if (i == 4)
 127                         break;
 128                 if (*p == 0) {
 129                         for (; i < 4; i++) {
 130                                 pos[i] = p;
 131                                 len[i] = 0;
 132                         }
 133                         break;
 134                 }
 135                 p++;
 136         }
 137
 138         /* Copy the entries in reverse order */
 139         p = out;
 140         leading = 1;
 141         for (i = 3; i >= 0; i--) {
 142                 memcpy(p, pos[i], len[i]);
 143                 if (len[i])
 144                         leading = 0;
 145                 p += len[i];
 146                 /* Need a . separator? */
 147                 if (!leading && i > 0 && len[i - 1])
 148                         *p++ = '.';
 149         }
 150         *p = '\0';
 151 }
 152
 153 static int
 154 getnetanswer(querybuf *answer, int anslen, int net_i, struct netent *ne,
 155              struct netent_data *ned, res_state statp)
 156 {
 157
 158         HEADER *hp;
 159         u_char *cp;
 160         int n;
 161         u_char *eom;
 162         int type, class, ancount, qdcount, haveanswer;
 163         char aux[MAXHOSTNAMELEN];
 164         char ans[MAXHOSTNAMELEN];
 165         char *in, *bp, *ep, **ap;
 166
 167         /*
 168          * find first satisfactory answer
 169          *
 170          *      answer --> +------------+  ( MESSAGE )
 171          *                 |   Header   |
 172          *                 +------------+
 173          *                 |  Question  | the question for the name server
 174          *                 +------------+
 175          *                 |   Answer   | RRs answering the question
 176          *                 +------------+
 177          *                 | Authority  | RRs pointing toward an authority
 178          *                 | Additional | RRs holding additional information
 179          *                 +------------+
 180          */
 181         eom = answer->buf + anslen;
 182         hp = &answer->hdr;
 183         ancount = ntohs(hp->ancount); /* #/records in the answer section */
 184         qdcount = ntohs(hp->qdcount); /* #/entries in the question section */
 185         bp = ned->netbuf;
 186         ep = ned->netbuf + sizeof(ned->netbuf);
 187         cp = answer->buf + HFIXEDSZ;
 188         if (!qdcount) {
 189                 if (hp->aa)
 190                         RES_SET_H_ERRNO(statp, HOST_NOT_FOUND);
 191                 else
 192                         RES_SET_H_ERRNO(statp, TRY_AGAIN);
 193                 return (-1);
 194         }
 195         while (qdcount-- > 0)
 196                 cp += __dn_skipname(cp, eom) + QFIXEDSZ;
 197         ap = ned->net_aliases;
 198         *ap = NULL;
 199         ne->n_aliases = ned->net_aliases;
 200         haveanswer = 0;
 201         while (--ancount >= 0 && cp < eom) {
 202                 n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
 203                 if ((n < 0) || !res_dnok(bp))
 204                         break;
 205                 cp += n;
 206                 ans[0] = '\0';
 207                 strncpy(&ans[0], bp, sizeof(ans) - 1);
 208                 ans[sizeof(ans) - 1] = '\0';
 209                 GETSHORT(type, cp);
 210                 GETSHORT(class, cp);
 211                 cp += INT32SZ;          /* TTL */
 212                 GETSHORT(n, cp);
 213                 if (class == C_IN && type == T_PTR) {
 214                         n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
 215                         if ((n < 0) || !res_hnok(bp)) {
 216                                 cp += n;
 217                                 return (-1);
 218                         }
 219                         cp += n;
 220                         *ap++ = bp;
 221                         n = strlen(bp) + 1;
 222                         bp += n;
 223                         ne->n_addrtype = (class == C_IN) ? AF_INET : AF_UNSPEC;
 224                         haveanswer++;
 225                 }
 226         }
 227         if (haveanswer) {
 228                 *ap = NULL;
 229                 switch (net_i) {
 230                 case BYADDR:
 231                         ne->n_name = *ne->n_aliases;
 232                         ne->n_net = 0L;
 233                         break;
 234                 case BYNAME:
 235                         in = *ne->n_aliases;
 236                         n = strlen(ans) + 1;
 237                         if (ep - bp < n) {
 238                                 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
 239                                 errno = ENOBUFS;
 240                                 return (-1);
 241                         }
 242                         strlcpy(bp, ans, ep - bp);
 243                         ne->n_name = bp;
 244                         if (strlen(in) + 1 > sizeof(aux)) {
 245                                 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
 246                                 errno = ENOBUFS;
 247                                 return (-1);
 248                         }
 249                         ipreverse(in, aux);
 250                         ne->n_net = inet_network(aux);
 251                         break;
 252                 }
 253                 ne->n_aliases++;
 254                 return (0);
 255         }
 256         RES_SET_H_ERRNO(statp, TRY_AGAIN);
 257         return (-1);
 258 }
 259
 260 int
 261 _dns_getnetbyaddr(void *rval, void *cb_data, va_list ap)
 262 {
 263         uint32_t net;
 264         int net_type;
 265         char *buffer;
 266         size_t buflen;
 267         int *errnop, *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, va_list ap)
 368 {
 369         const char *net;
 370         char *buffer;
 371         size_t buflen;
 372         int *errnop, *h_errnop;
 373         struct netent *nptr, ne;
 374         struct netent_data *ned;
 375         int anslen, error;
 376         querybuf *buf;
 377         char qbuf[MAXDNAME];
 378         res_state statp;
 379
 380         net = va_arg(ap, const char *);
 381         nptr = va_arg(ap, struct netent *);
 382         buffer = va_arg(ap, char *);
 383         buflen = va_arg(ap, size_t);
 384         errnop = va_arg(ap, int *);
 385         h_errnop = va_arg(ap, int *);
 386
 387         statp = __res_state();
 388         if ((statp->options & RES_INIT) == 0 && res_ninit(statp) == -1) {
 389                 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
 390                 *h_errnop = statp->res_h_errno;
 391                 return (NS_UNAVAIL);
 392         }
 393         if ((ned = __netent_data_init()) == NULL) {
 394                 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
 395                 *h_errnop = statp->res_h_errno;
 396                 return (NS_UNAVAIL);
 397         }
 398         if ((buf = malloc(sizeof(*buf))) == NULL) {
 399                 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
 400                 *h_errnop = statp->res_h_errno;
 401                 return (NS_NOTFOUND);
 402         }
 403
 404         *((struct netent **)rval) = NULL;
 405
 406         strncpy(qbuf, net, sizeof(qbuf) - 1);
 407         qbuf[sizeof(qbuf) - 1] = '\0';
 408         anslen = res_nsearch(statp, qbuf, C_IN, T_PTR, (u_char *)buf,
 409             sizeof(*buf));
 410         if (anslen < 0) {
 411                 free(buf);
 412 #ifdef DEBUG
 413                 if (statp->options & RES_DEBUG)
 414                         printf("res_nsearch failed\n");
 415 #endif
 416                 return (NS_UNAVAIL);
 417         } else if (anslen > sizeof(*buf)) {
 418                 free(buf);
 419 #ifdef DEBUG
 420                 if (statp->options & RES_DEBUG)
 421                         printf("res_search static buffer too small\n");
 422 #endif
 423                 return (NS_UNAVAIL);
 424         }
 425         error = getnetanswer(buf, anslen, BYNAME, &ne, ned, statp);
 426         free(buf);
 427         if (error != 0) {
 428                 *h_errnop = statp->res_h_errno;
 429                 return (NS_NOTFOUND);
 430         }
 431         if (__copy_netent(&ne, nptr, buffer, buflen) != 0) {
 432                 *h_errnop = statp->res_h_errno;
 433                 return (NS_NOTFOUND);
 434         }
 435         *((struct netent **)rval) = nptr;
 436         return (NS_SUCCESS);
 437 }
 438
 439 void
 440 _setnetdnsent(int stayopen)
 441 {
 442         res_state statp;
 443
 444         statp = __res_state();
 445         if ((statp->options & RES_INIT) == 0 && res_ninit(statp) == -1)
 446                 return;
 447         if (stayopen)
 448                 statp->options |= RES_STAYOPEN | RES_USEVC;
 449 }
 450
 451 void
 452 _endnetdnsent(void)
 453 {
 454         res_state statp;
 455
 456         statp = __res_state();
 457         statp->options &= ~(RES_STAYOPEN | RES_USEVC);
 458         res_nclose(statp);
 459 }