StdLib/BsdSocketLib/getnetbydns.c

   1 /*-
   2  * Copyright (c) 1985, 1988, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Portions copyright (c) 1999, 2000
   6  * Intel Corporation.
   7  * All rights reserved.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  *
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  *
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in the
  18  *    documentation and/or other materials provided with the distribution.
  19  *
  20  * 3. All advertising materials mentioning features or use of this software
  21  *    must display the following acknowledgement:
  22  *
  23  *    This product includes software developed by the University of
  24  *    California, Berkeley, Intel Corporation, and its contributors.
  25  *
  26  * 4. Neither the name of University, Intel Corporation, or their respective
  27  *    contributors may be used to endorse or promote products derived from
  28  *    this software without specific prior written permission.
  29  *
  30  * THIS SOFTWARE IS PROVIDED BY THE REGENTS, INTEL CORPORATION AND
  31  * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
  32  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  33  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS,
  34  * INTEL CORPORATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  35  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  36  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  37  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  38  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  39  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  40  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  41  * -
  42  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
  43  *
  44  * Permission to use, copy, modify, and distribute this software for any
  45  * purpose with or without fee is hereby granted, provided that the above
  46  * copyright notice and this permission notice appear in all copies, and that
  47  * the name of Digital Equipment Corporation not be used in advertising or
  48  * publicity pertaining to distribution of the document or software without
  49  * specific, written prior permission.
  50  *
  51  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
  52  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
  53  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
  54  * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  55  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  56  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  57  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  58  * SOFTWARE.
  59  * -
  60  * --Copyright--
  61  */
  62 /* Portions Copyright (c) 1993 Carlos Leandro and Rui Salgueiro
  63  *      Dep. Matematica Universidade de Coimbra, Portugal, Europe
  64  *
  65  * Permission to use, copy, modify, and distribute this software for any
  66  * purpose with or without fee is hereby granted, provided that the above
  67  * copyright notice and this permission notice appear in all copies.
  68  */
  69
  70 #if defined(LIBC_SCCS) && !defined(lint)
  71 static char sccsid[] = "@(#)gethostnamadr.c     8.1 (Berkeley) 6/4/93";
  72 static char rcsid[] = "$Id: getnetbydns.c,v 1.1.1.1 2003/11/19 01:51:27 kyu3 Exp $";
  73 #endif /* LIBC_SCCS and not lint */
  74
  75 #include <sys/param.h>
  76 #include <sys/socket.h>
  77 #include <netinet/in.h>
  78 #include <arpa/inet.h>
  79 #include <arpa/nameser.h>
  80
  81 #include <stdio.h>
  82 #include <netdb.h>
  83 #include <resolv.h>
  84 #include <ctype.h>
  85 #include <errno.h>
  86 #include <string.h>
  87 #include <unistd.h>
  88 #ifdef _ORG_FREEBSD_
  89 #include <syslog.h>
  90 #endif
  91
  92 #include "res_config.h"
  93 #include "Socklib_internals.h"
  94
  95 extern int h_errno;
  96
  97 #define BYADDR 0
  98 #define BYNAME 1
  99 #define MAXALIASES      35
 100
 101 #if PACKETSZ > 1024
 102 #define MAXPACKET       PACKETSZ
 103 #else
 104 #define MAXPACKET       1024
 105 #endif
 106
 107 typedef union {
 108         HEADER  hdr;
 109         u_char  buf[MAXPACKET];
 110 } querybuf;
 111
 112 typedef union {
 113         long    al;
 114         char    ac;
 115 } align;
 116
 117 static struct netent *
 118 getnetanswer(querybuf *answer, int anslen, int net_i)
 119 {
 120
 121         register HEADER *hp;
 122         register u_char *cp;
 123         register int n;
 124         u_char *eom;
 125         int type, class, buflen, ancount, qdcount, haveanswer, i, nchar;
 126         char aux1[MAXHOSTNAMELEN], aux2[MAXHOSTNAMELEN], ans[MAXHOSTNAMELEN];
 127         char *in, *st, *pauxt, *bp, **ap;
 128         char *paux1 = &aux1[0], *paux2 = &aux2[0], flag = 0;
 129 static  struct netent net_entry;
 130 static  char *net_aliases[MAXALIASES], netbuf[PACKETSZ];
 131
 132         /*
 133          * find first satisfactory answer
 134          *
 135          *      answer --> +------------+  ( MESSAGE )
 136          *                 |   Header   |
 137          *                 +------------+
 138          *                 |  Question  | the question for the name server
 139          *                 +------------+
 140          *                 |   Answer   | RRs answering the question
 141          *                 +------------+
 142          *                 | Authority  | RRs pointing toward an authority
 143          *                 | Additional | RRs holding additional information
 144          *                 +------------+
 145          */
 146         eom = answer->buf + anslen;
 147         hp = &answer->hdr;
 148         ancount = ntohs(hp->ancount); /* #/records in the answer section */
 149         qdcount = ntohs(hp->qdcount); /* #/entries in the question section */
 150         bp = netbuf;
 151         buflen = sizeof(netbuf);
 152         cp = answer->buf + HFIXEDSZ;
 153         if (!qdcount) {
 154                 if (hp->aa)
 155                         h_errno = HOST_NOT_FOUND;
 156                 else
 157                         h_errno = TRY_AGAIN;
 158                 return (NULL);
 159         }
 160         while (qdcount-- > 0)
 161                 cp += __dn_skipname(cp, eom) + QFIXEDSZ;
 162         ap = net_aliases;
 163         *ap = NULL;
 164         net_entry.n_aliases = net_aliases;
 165         haveanswer = 0;
 166         while (--ancount >= 0 && cp < eom) {
 167                 n = dn_expand(answer->buf, eom, cp, bp, buflen);
 168                 if ((n < 0) || !res_dnok(bp))
 169                         break;
 170                 cp += n;
 171                 ans[0] = '\0';
 172                 (void)strncpy(&ans[0], bp, sizeof(ans) - 1);
 173                 ans[sizeof(ans) - 1] = '\0';
 174                 GETSHORT(type, cp);
 175                 GETSHORT(class, cp);
 176                 cp += INT32SZ;          /* TTL */
 177                 GETSHORT(n, cp);
 178                 if (class == C_IN && type == T_PTR) {
 179                         n = dn_expand(answer->buf, eom, cp, bp, buflen);
 180                         if ((n < 0) || !res_hnok(bp)) {
 181                                 cp += n;
 182                                 return (NULL);
 183                         }
 184                         cp += n;
 185                         *ap++ = bp;
 186                         bp += strlen(bp) + 1;
 187                         net_entry.n_addrtype =
 188                                 (class == C_IN) ? AF_INET : AF_UNSPEC;
 189                         haveanswer++;
 190                 }
 191         }
 192         if (haveanswer) {
 193                 *ap = NULL;
 194                 switch (net_i) {
 195                 case BYADDR:
 196                         net_entry.n_name = *net_entry.n_aliases;
 197                         net_entry.n_net = 0L;
 198                         break;
 199                 case BYNAME:
 200                         in = *net_entry.n_aliases;
 201                         net_entry.n_name = &ans[0];
 202                         aux2[0] = '\0';
 203                         for (i = 0; i < 4; i++) {
 204                                 for (st = in, nchar = 0;
 205                                      *st != '.';
 206                                      st++, nchar++)
 207                                         ;
 208                                 if (nchar != 1 || *in != '0' || flag) {
 209                                         flag = 1;
 210                                         (void)strncpy(paux1,
 211                                                       (i==0) ? in : in-1,
 212                                                       (i==0) ?nchar : nchar+1);
 213                                         paux1[(i==0) ? nchar : nchar+1] = '\0';
 214                                         pauxt = paux2;
 215                                         paux2 = strcat(paux1, paux2);
 216                                         paux1 = pauxt;
 217                                 }
 218                                 in = ++st;
 219                         }
 220                         net_entry.n_net = inet_network(paux2);
 221                         break;
 222                 }
 223                 net_entry.n_aliases++;
 224                 return (&net_entry);
 225         }
 226         h_errno = TRY_AGAIN;
 227         return (NULL);
 228 }
 229
 230 struct netent *
 231 _getnetbydnsaddr(register unsigned long net, register int net_type)
 232 {
 233         unsigned int netbr[4];
 234         int nn, anslen;
 235         querybuf buf;
 236         char qbuf[MAXDNAME];
 237         unsigned long net2;
 238         struct netent *net_entry;
 239
 240         if (net_type != AF_INET)
 241                 return (NULL);
 242
 243         for (nn = 4, net2 = net; net2; net2 >>= 8)
 244                 netbr[--nn] = net2 & 0xff;
 245         switch (nn) {
 246         case 3:         /* Class A */
 247                 sprintf(qbuf, "0.0.0.%u.in-addr.arpa", netbr[3]);
 248                 break;
 249         case 2:         /* Class B */
 250                 sprintf(qbuf, "0.0.%u.%u.in-addr.arpa", netbr[3], netbr[2]);
 251                 break;
 252         case 1:         /* Class C */
 253                 sprintf(qbuf, "0.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2],
 254                     netbr[1]);
 255                 break;
 256         case 0:         /* Class D - E */
 257                 sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2],
 258                     netbr[1], netbr[0]);
 259                 break;
 260         }
 261         anslen = res_query(qbuf, C_IN, T_PTR, (u_char *)&buf, sizeof(buf));
 262         if (anslen < 0) {
 263 #ifdef DEBUG
 264                 if (_res.options & RES_DEBUG)
 265                         printf("res_query failed\n");
 266 #endif
 267                 return (NULL);
 268         }
 269         net_entry = getnetanswer(&buf, anslen, BYADDR);
 270         if (net_entry) {
 271                 unsigned u_net = net;   /* maybe net should be unsigned ? */
 272
 273                 /* Strip trailing zeros */
 274                 while ((u_net & 0xff) == 0 && u_net != 0)
 275                         u_net >>= 8;
 276                 net_entry->n_net = u_net;
 277                 return (net_entry);
 278         }
 279         return (NULL);
 280 }
 281
 282 struct netent *
 283 _getnetbydnsname(register const char *net)
 284 {
 285         int anslen;
 286         querybuf buf;
 287         char qbuf[MAXDNAME];
 288
 289         if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
 290                 h_errno = NETDB_INTERNAL;
 291                 return (NULL);
 292         }
 293         strncpy(qbuf, net, sizeof(qbuf) - 1);
 294         qbuf[sizeof(qbuf) - 1] = '\0';
 295         anslen = res_search(qbuf, C_IN, T_PTR, (u_char *)&buf, sizeof(buf));
 296         if (anslen < 0) {
 297 #ifdef DEBUG
 298                 if (_res.options & RES_DEBUG)
 299                         printf("res_query failed\n");
 300 #endif
 301                 return (NULL);
 302         }
 303         return getnetanswer(&buf, anslen, BYNAME);
 304 }
 305
 306 void
 307 _setnetdnsent(int stayopen)
 308 {
 309         if (stayopen)
 310                 _res.options |= RES_STAYOPEN | RES_USEVC;
 311 }
 312
 313 void
 314 _endnetdnsent()
 315 {
 316         _res.options &= ~(RES_STAYOPEN | RES_USEVC);
 317         res_close();
 318 }