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/types.h>
  48 #include <sys/param.h>
  49 #include <sys/socket.h>
  50 #include <netinet/in.h>
  51 #include <arpa/inet.h>
  52 #include <arpa/nameser.h>
  53
  54 #include <stdio.h>
  55 #include <netdb.h>
  56 #include <resolv.h>
  57 #include <ctype.h>
  58 #include <errno.h>
  59 #include <string.h>
  60
  61 #ifndef h_errno
  62 extern int h_errno;
  63 #endif
  64
  65 #if defined(mips) && defined(SYSTYPE_BSD43) && !defined(errno)
  66 extern int errno;
  67 #endif
  68
  69 struct netent *_getnetbyaddr __P((long net, int type));
  70 struct netent *_getnetbyname __P((const char *name));
  71
  72 #define BYADDR 0
  73 #define BYNAME 1
  74 #define MAXALIASES      35
  75
  76 #if PACKETSZ > 1024
  77 #define MAXPACKET       PACKETSZ
  78 #else
  79 #define MAXPACKET       1024
  80 #endif
  81
  82 typedef union {
  83         HEADER  hdr;
  84         u_char  buf[MAXPACKET];
  85 } querybuf;
  86
  87 typedef union {
  88         long    al;
  89         char    ac;
  90 } align;
  91
  92 static struct netent *
  93 getnetanswer(answer, anslen, net_i)
  94         querybuf *answer;
  95         int anslen;
  96         int net_i;
  97 {
  98
  99         register HEADER *hp;
 100         register u_char *cp;
 101         register int n;
 102         u_char *eom;
 103         int type, class, buflen, ancount, qdcount, haveanswer, i, nchar;
 104         char aux1[30], aux2[30], ans[30], *in, *st, *pauxt, *bp, **ap,
 105                 *paux1 = &aux1[0], *paux2 = &aux2[0], flag = 0;
 106 static  struct netent net_entry;
 107 static  char *net_aliases[MAXALIASES], netbuf[BUFSIZ+1];
 108
 109         /*
 110          * find first satisfactory answer
 111          *
 112          *      answer --> +------------+  ( MESSAGE )
 113          *                 |   Header   |
 114          *                 +------------+
 115          *                 |  Question  | the question for the name server
 116          *                 +------------+
 117          *                 |   Answer   | RRs answering the question
 118          *                 +------------+
 119          *                 | Authority  | RRs pointing toward an authority
 120          *                 | Additional | RRs holding additional information
 121          *                 +------------+
 122          */
 123         eom = answer->buf + anslen;
 124         hp = &answer->hdr;
 125         ancount = ntohs(hp->ancount); /* #/records in the answer section */
 126         qdcount = ntohs(hp->qdcount); /* #/entries in the question section */
 127         bp = netbuf;
 128         buflen = sizeof(netbuf);
 129         cp = answer->buf + HFIXEDSZ;
 130         if (!qdcount) {
 131                 if (hp->aa)
 132                         __set_h_errno (HOST_NOT_FOUND);
 133                 else
 134                         __set_h_errno (TRY_AGAIN);
 135                 return (NULL);
 136         }
 137         while (qdcount-- > 0)
 138                 cp += __dn_skipname(cp, eom) + QFIXEDSZ;
 139         ap = net_aliases;
 140         *ap = NULL;
 141         net_entry.n_aliases = net_aliases;
 142         haveanswer = 0;
 143         while (--ancount >= 0 && cp < eom) {
 144                 n = dn_expand(answer->buf, eom, cp, bp, buflen);
 145                 if ((n < 0) || !res_dnok(bp))
 146                         break;
 147                 cp += n;
 148                 ans[0] = '\0';
 149                 (void)strcpy(&ans[0], bp);
 150                 GETSHORT(type, cp);
 151                 GETSHORT(class, cp);
 152                 cp += INT32SZ;          /* TTL */
 153                 GETSHORT(n, cp);
 154                 if (class == C_IN && type == T_PTR) {
 155                         n = dn_expand(answer->buf, eom, cp, bp, buflen);
 156                         if ((n < 0) || !res_hnok(bp)) {
 157                                 cp += n;
 158                                 return (NULL);
 159                         }
 160                         cp += n;
 161                         *ap++ = bp;
 162                         bp += strlen(bp) + 1;
 163                         net_entry.n_addrtype =
 164                                 (class == C_IN) ? AF_INET : AF_UNSPEC;
 165                         haveanswer++;
 166                 }
 167         }
 168         if (haveanswer) {
 169                 *ap = NULL;
 170                 switch (net_i) {
 171                 case BYADDR:
 172                         net_entry.n_name = *net_entry.n_aliases;
 173                         net_entry.n_net = 0L;
 174                         break;
 175                 case BYNAME:
 176                         in = *net_entry.n_aliases;
 177                         net_entry.n_name = &ans[0];
 178                         aux2[0] = '\0';
 179                         for (i = 0; i < 4; i++) {
 180                                 for (st = in, nchar = 0;
 181                                      *st != '.';
 182                                      st++, nchar++)
 183                                         ;
 184                                 if (nchar != 1 || *in != '0' || flag) {
 185                                         flag = 1;
 186                                         (void)strncpy(paux1,
 187                                                       (i==0) ? in : in-1,
 188                                                       (i==0) ?nchar : nchar+1);
 189                                         paux1[(i==0) ? nchar : nchar+1] = '\0';
 190                                         pauxt = paux2;
 191                                         paux2 = strcat(paux1, paux2);
 192                                         paux1 = pauxt;
 193                                 }
 194                                 in = ++st;
 195                         }
 196                         net_entry.n_net = inet_network(paux2);
 197                         break;
 198                 }
 199                 net_entry.n_aliases++;
 200                 return (&net_entry);
 201         }
 202         __set_h_errno (TRY_AGAIN);
 203         return (NULL);
 204 }
 205
 206 struct netent *
 207 getnetbyaddr(net, net_type)
 208         register u_long net;
 209         register int net_type;
 210 {
 211         unsigned int netbr[4];
 212         int nn, anslen;
 213         querybuf buf;
 214         char qbuf[MAXDNAME];
 215         u_int32_t net2;         /* Changed from unsigned long --roland */
 216         struct netent *net_entry;
 217
 218         if (net_type != AF_INET)
 219                 return (_getnetbyaddr(net, net_type));
 220
 221         for (nn = 4, net2 = net; net2; net2 >>= 8)
 222                 netbr[--nn] = net2 & 0xff;
 223         switch (nn) {
 224         case 3:         /* Class A */
 225                 sprintf(qbuf, "0.0.0.%u.in-addr.arpa", netbr[3]);
 226                 break;
 227         case 2:         /* Class B */
 228                 sprintf(qbuf, "0.0.%u.%u.in-addr.arpa", netbr[3], netbr[2]);
 229                 break;
 230         case 1:         /* Class C */
 231                 sprintf(qbuf, "0.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2],
 232                     netbr[1]);
 233                 break;
 234         case 0:         /* Class D - E */
 235                 sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2],
 236                     netbr[1], netbr[0]);
 237                 break;
 238         }
 239         anslen = res_query(qbuf, C_IN, T_PTR, (u_char *)&buf, sizeof(buf));
 240         if (anslen < 0) {
 241 #ifdef DEBUG
 242                 if (_res.options & RES_DEBUG)
 243                         printf("res_query failed\n");
 244 #endif
 245                 if (errno == ECONNREFUSED)
 246                         return (_getnetbyaddr(net, net_type));
 247                 return (NULL);
 248         }
 249         net_entry = getnetanswer(&buf, anslen, BYADDR);
 250         if (net_entry) {
 251                 unsigned u_net = net;   /* maybe net should be unsigned ? */
 252
 253                 /* Strip trailing zeros */
 254                 while ((u_net & 0xff) == 0 && u_net != 0)
 255                         u_net >>= 8;
 256                 net_entry->n_net = u_net;
 257                 return (net_entry);
 258         }
 259         return (_getnetbyaddr(net, net_type));
 260 }
 261
 262 struct netent *
 263 getnetbyname(net)
 264         register const char *net;
 265 {
 266         int anslen;
 267         querybuf buf;
 268         char qbuf[MAXDNAME];
 269         struct netent *net_entry;
 270
 271         if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
 272                 __set_h_errno (NETDB_INTERNAL);
 273                 return (NULL);
 274         }
 275         strcpy(&qbuf[0], net);
 276         anslen = res_search(qbuf, C_IN, T_PTR, (u_char *)&buf, sizeof(buf));
 277         if (anslen < 0) {
 278 #ifdef DEBUG
 279                 if (_res.options & RES_DEBUG)
 280                         printf("res_query failed\n");
 281 #endif
 282                 if (errno == ECONNREFUSED)
 283                         return (_getnetbyname(net));
 284                 return (_getnetbyname(net));
 285         }
 286         net_entry = getnetanswer(&buf, anslen, BYNAME);
 287         if (net_entry)
 288                 return (net_entry);
 289         return (_getnetbyname(net));
 290 }