resolv/getnetnamadr.c

   1 /* Copyright (c) 1993 Carlos Leandro and Rui Salgueiro
   2  *      Dep. Matematica Universidade de Coimbra, Portugal, Europe
   3  *
   4  * Permission to use, copy, modify, and distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  */
   8 /*
   9  * Copyright (c) 1983, 1993
  10  *      The Regents of the University of California.  All rights reserved.
  11  *
  12  * Redistribution and use in source and binary forms, with or without
  13  * modification, are permitted provided that the following conditions
  14  * are met:
  15  * 1. Redistributions of source code must retain the above copyright
  16  *    notice, this list of conditions and the following disclaimer.
  17  * 2. Redistributions in binary form must reproduce the above copyright
  18  *    notice, this list of conditions and the following disclaimer in the
  19  *    documentation and/or other materials provided with the distribution.
  20  * 3. All advertising materials mentioning features or use of this software
  21  *    must display the following acknowledgement:
  22  *      This product includes software developed by the University of
  23  *      California, Berkeley and its contributors.
  24  * 4. Neither the name of the University nor the names of its contributors
  25  *    may be used to endorse or promote products derived from this software
  26  *    without specific prior written permission.
  27  *
  28  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  29  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  30  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  31  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  32  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  33  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  34  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  35  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  36  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  37  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  38  * SUCH DAMAGE.
  39  */
  40
  41 #if defined(LIBC_SCCS) && !defined(lint)
  42 static char sccsid[] = "@(#)getnetbyaddr.c      8.1 (Berkeley) 6/4/93";
  43 static char sccsid_[] = "from getnetnamadr.c    1.4 (Coimbra) 93/06/03";
  44 static char rcsid[] = "$Id$";
  45 #endif /* LIBC_SCCS and not lint */
  46
  47 #include <sys/param.h>
  48 #include <sys/socket.h>
  49 #include <netinet/in.h>
  50 #include <arpa/inet.h>
  51 #include <arpa/nameser.h>
  52
  53 #include <stdio.h>
  54 #include <netdb.h>
  55 #include <resolv.h>
  56 #include <ctype.h>
  57 #include <errno.h>
  58 #include <string.h>
  59 #include "conf/portability.h"
  60
  61 extern int h_errno;
  62
  63 #if defined(mips) && defined(SYSTYPE_BSD43)
  64 extern int errno;
  65 #endif
  66
  67 struct netent *_getnetbyaddr __P((long net, int type));
  68 #if defined(sun)
  69 struct netent *_getnetbyname __P((char *name));
  70 #else
  71 struct netent *_getnetbyname __P((const char *name));
  72 #endif
  73
  74 #define BYADDR 0
  75 #define BYNAME 1
  76 #define MAXALIASES      35
  77
  78 #if PACKETSZ > 1024
  79 #define MAXPACKET       PACKETSZ
  80 #else
  81 #define MAXPACKET       1024
  82 #endif
  83
  84 typedef union {
  85         HEADER  hdr;
  86         u_char  buf[MAXPACKET];
  87 } querybuf;
  88
  89 typedef union {
  90         long    al;
  91         char    ac;
  92 } align;
  93
  94 static struct netent *
  95 getnetanswer(answer, anslen, net_i)
  96         querybuf *answer;
  97         int anslen;
  98         int net_i;
  99 {
 100
 101         register HEADER *hp;
 102         register u_char *cp;
 103         register int n;
 104         u_char *eom;
 105         int type, class, buflen, ancount, qdcount, haveanswer, i, nchar,
 106                 getclass = C_ANY, net_length = 0;
 107         char aux1[30], aux2[30], ans[30], *in, *st, *pauxt, *bp, **ap,
 108                 *paux1 = &aux1[0], *paux2 = &aux2[0], flag = 0;
 109 static  struct netent net_entry;
 110 static  char *net_aliases[MAXALIASES], netbuf[BUFSIZ+1];
 111
 112         /*
 113          * find first satisfactory answer
 114          *
 115          *      answer --> +------------+  ( MESSAGE )
 116          *                 |   Header   |
 117          *                 +------------+
 118          *                 |  Question  | the question for the name server
 119          *                 +------------+
 120          *                 |   Answer   | RRs answering the question
 121          *                 +------------+
 122          *                 | Authority  | RRs pointing toward an authority
 123          *                 | Additional | RRs holding additional information
 124          *                 +------------+
 125          */
 126         eom = answer->buf + anslen;
 127         hp = &answer->hdr;
 128         ancount = ntohs(hp->ancount); /* #/records in the answer section */
 129         qdcount = ntohs(hp->qdcount); /* #/entries in the question section */
 130         bp = netbuf;
 131         buflen = sizeof(netbuf);
 132         cp = answer->buf + HFIXEDSZ;
 133         if (!qdcount) {
 134                 if (hp->aa)
 135                         h_errno = HOST_NOT_FOUND;
 136                 else
 137                         h_errno = TRY_AGAIN;
 138                 return (NULL);
 139         }
 140         while (qdcount-- > 0)
 141                 cp += __dn_skipname(cp, eom) + QFIXEDSZ;
 142         ap = net_aliases;
 143         *ap = NULL;
 144         net_entry.n_aliases = net_aliases;
 145         haveanswer = 0;
 146         while (--ancount >= 0 && cp < eom) {
 147                 n = dn_expand(answer->buf, eom, cp, bp, buflen);
 148                 if (n < 0)
 149                         break;
 150                 cp += n;
 151                 ans[0] = '\0';
 152                 (void)strcpy(&ans[0], bp);
 153                 GETSHORT(type, cp);
 154                 GETSHORT(class, cp);
 155                 cp += INT32SZ;          /* TTL */
 156                 GETSHORT(n, cp);
 157                 if (class == C_IN && type == T_PTR) {
 158                         n = dn_expand(answer->buf, eom, cp, bp, buflen);
 159                         if (n < 0) {
 160                                 cp += n;
 161                                 return (NULL);
 162                         }
 163                         cp += n;
 164                         *ap++ = bp;
 165                         bp += strlen(bp) + 1;
 166                         net_entry.n_addrtype =
 167                                 (class == C_IN) ? AF_INET : AF_UNSPEC;
 168                         haveanswer++;
 169                 }
 170         }
 171         if (haveanswer) {
 172                 *ap = NULL;
 173                 switch (net_i) {
 174                 case BYADDR:
 175                         net_entry.n_name = *net_entry.n_aliases;
 176                         net_entry.n_net = 0L;
 177                         break;
 178                 case BYNAME:
 179                         in = *net_entry.n_aliases;
 180                         net_entry.n_name = &ans[0];
 181                         aux2[0] = '\0';
 182                         for (i = 0; i < 4; i++) {
 183                                 for (st = in, nchar = 0;
 184                                      *st != '.';
 185                                      st++, nchar++)
 186                                         ;
 187                                 if (nchar != 1 || *in != '0' || flag) {
 188                                         flag = 1;
 189                                         (void)strncpy(paux1,
 190                                                       (i==0) ? in : in-1,
 191                                                       (i==0) ?nchar : nchar+1);
 192                                         paux1[(i==0) ? nchar : nchar+1] = '\0';
 193                                         pauxt = paux2;
 194                                         paux2 = strcat(paux1, paux2);
 195                                         paux1 = pauxt;
 196                                 }
 197                                 in = ++st;
 198                         }
 199                         net_entry.n_net = inet_network(paux2);
 200                         break;
 201                 }
 202                 net_entry.n_aliases++;
 203                 return (&net_entry);
 204         }
 205         h_errno = TRY_AGAIN;
 206         return (NULL);
 207 }
 208
 209 struct netent *
 210 getnetbyaddr(net, net_type)
 211         register long net;
 212         register int net_type;
 213 {
 214         unsigned int netbr[4];
 215         int nn, anslen;
 216         querybuf buf;
 217         char qbuf[MAXDNAME];
 218         unsigned long net2;
 219         struct netent *net_entry;
 220
 221         if (net_type != AF_INET)
 222                 return (_getnetbyaddr(net, net_type));
 223
 224         for (nn = 4, net2 = net; net2; net2 >>= 8)
 225                 netbr[--nn] = net2 & 0xff;
 226         switch (nn) {
 227         case 3:         /* Class A */
 228                 sprintf(qbuf, "0.0.0.%u.in-addr.arpa", netbr[3]);
 229                 break;
 230         case 2:         /* Class B */
 231                 sprintf(qbuf, "0.0.%u.%u.in-addr.arpa", netbr[3], netbr[2]);
 232                 break;
 233         case 1:         /* Class C */
 234                 sprintf(qbuf, "0.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2],
 235                     netbr[1]);
 236                 break;
 237         case 0:         /* Class D - E */
 238                 sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2],
 239                     netbr[1], netbr[0]);
 240                 break;
 241         }
 242         anslen = res_query(qbuf, C_IN, T_PTR, (u_char *)&buf, sizeof(buf));
 243         if (anslen < 0) {
 244 #ifdef DEBUG
 245                 if (_res.options & RES_DEBUG)
 246                         printf("res_query failed\n");
 247 #endif
 248                 if (errno == ECONNREFUSED)
 249                         return (_getnetbyaddr(net, net_type));
 250                 return (NULL);
 251         }
 252         net_entry = getnetanswer(&buf, anslen, BYADDR);
 253         if (net_entry) {
 254                 unsigned u_net = net;   /* maybe net should be unsigned ? */
 255
 256                 /* Strip trailing zeros */
 257                 while ((u_net & 0xff) == 0 && u_net != 0)
 258                         u_net >>= 8;
 259                 net_entry->n_net = u_net;
 260                 return (net_entry);
 261         }
 262         return (_getnetbyaddr(net, net_type));
 263 }
 264
 265 struct netent *
 266 getnetbyname(net)
 267 #if defined(sun)
 268         register char *net;
 269 #else
 270         register const char *net;
 271 #endif
 272 {
 273         unsigned int netbr[4];
 274         int anslen;
 275         querybuf buf;
 276         char qbuf[MAXDNAME];
 277         struct netent *net_entry;
 278
 279         strcpy(&qbuf[0],net);
 280         anslen = res_search(qbuf, C_IN, T_PTR, (u_char *)&buf, sizeof(buf));
 281         if (anslen < 0) {
 282 #ifdef DEBUG
 283                 if (_res.options & RES_DEBUG)
 284                         printf("res_query failed\n");
 285 #endif
 286                 if (errno == ECONNREFUSED)
 287                         return (_getnetbyname(net));
 288                 return (_getnetbyname(net));
 289         }
 290         net_entry = getnetanswer(&buf, anslen, BYNAME);
 291         if (net_entry)
 292                 return (net_entry);
 293         return (_getnetbyname(net));
 294 }