nss/nss_dns/dns-network.c

   1 /* Copyright (C) 1996 Free Software Foundation, Inc.
   2 This file is part of the GNU C Library.
   3 Extended from original form by Ulrich Drepper <drepper@cygnus.com>, 1996.
   4
   5 The GNU C Library is free software; you can redistribute it and/or
   6 modify it under the terms of the GNU Library General Public License as
   7 published by the Free Software Foundation; either version 2 of the
   8 License, or (at your option) any later version.
   9
  10 The GNU C Library is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13 Library General Public License for more details.
  14
  15 You should have received a copy of the GNU Library General Public
  16 License along with the GNU C Library; see the file COPYING.LIB.  If
  17 not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18 Boston, MA 02111-1307, USA.  */
  19
  20 /* Parts of this file are plain copies of the file `getnetnamadr.c' from
  21    the bind package and it has the following copyright.  */
  22
  23 /* Copyright (c) 1993 Carlos Leandro and Rui Salgueiro
  24  *      Dep. Matematica Universidade de Coimbra, Portugal, Europe
  25  *
  26  * Permission to use, copy, modify, and distribute this software for any
  27  * purpose with or without fee is hereby granted, provided that the above
  28  * copyright notice and this permission notice appear in all copies.
  29  */
  30 /*
  31  * Copyright (c) 1983, 1993
  32  *      The Regents of the University of California.  All rights reserved.
  33  *
  34  * Redistribution and use in source and binary forms, with or without
  35  * modification, are permitted provided that the following conditions
  36  * are met:
  37  * 1. Redistributions of source code must retain the above copyright
  38  *    notice, this list of conditions and the following disclaimer.
  39  * 2. Redistributions in binary form must reproduce the above copyright
  40  *    notice, this list of conditions and the following disclaimer in the
  41  *    documentation and/or other materials provided with the distribution.
  42  * 3. All advertising materials mentioning features or use of this software
  43  *    must display the following acknowledgement:
  44  *      This product includes software developed by the University of
  45  *      California, Berkeley and its contributors.
  46  * 4. Neither the name of the University nor the names of its contributors
  47  *    may be used to endorse or promote products derived from this software
  48  *    without specific prior written permission.
  49  *
  50  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  51  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  52  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  53  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  54  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  55  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  56  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  57  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  58  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  59  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  60  * SUCH DAMAGE.
  61  */
  62
  63 #include <ctype.h>
  64 #include <errno.h>
  65 #include <netdb.h>
  66 #include <stdio.h>
  67 #include <stdlib.h>
  68 #include <string.h>
  69
  70 #include "nsswitch.h"
  71 #include <arpa/inet.h>
  72
  73 /* Maximum number of aliases we allow.  */
  74 #define MAX_NR_ALIASES  48
  75
  76
  77 #if PACKETSZ > 1024
  78 #define MAXPACKET       PACKETSZ
  79 #else
  80 #define MAXPACKET       1024
  81 #endif
  82
  83
  84 typedef enum
  85 {
  86   BYADDR,
  87   BYNAME
  88 } lookup_method;
  89
  90
  91 /* We need this time later.  */
  92 typedef union querybuf
  93 {
  94   HEADER hdr;
  95   u_char buf[MAXPACKET];
  96 } querybuf;
  97
  98
  99 /* Protortypes for local functions.  */
 100 static int getanswer_r (const querybuf *answer, int anslen,
 101                         struct netent *result, char *buffer, int buflen,
 102                         lookup_method net_i);
 103
 104
 105 int
 106 _nss_dns_getnetbyname_r (const char *name, struct netent *result,
 107                          char *buffer, int buflen)
 108 {
 109   /* Return entry for network with NAME.  */
 110   querybuf net_buffer;
 111   int anslen;
 112   char *qbuf;
 113
 114   qbuf = strdupa (name);
 115   anslen = res_search (qbuf, C_IN, T_PTR, (u_char *) &net_buffer,
 116                        sizeof (querybuf));
 117   if (anslen < 0)
 118     /* Nothing found.  */
 119     return (errno == ECONNREFUSED
 120             || errno == EPFNOSUPPORT
 121             || errno == EAFNOSUPPORT)
 122       ? NSS_STATUS_UNAVAIL : NSS_STATUS_NOTFOUND;
 123
 124   return getanswer_r (&net_buffer, anslen, result, buffer, buflen, BYNAME);
 125 }
 126
 127
 128 int
 129 _nss_dns_getnetbyaddr_r (long net, int type, struct netent *result,
 130                          char *buffer, int buflen)
 131 {
 132   /* Return entry for network with NAME.  */
 133   int status;
 134   querybuf net_buffer;
 135   unsigned int net_bytes[4];
 136   char qbuf[MAXDNAME];
 137   int cnt, anslen;
 138   u_int32_t net2;
 139
 140   /* No net address lookup for IPv6 yet.  */
 141   if (type != AF_INET)
 142     return NSS_STATUS_UNAVAIL;
 143
 144   net2 = (u_int32_t) net;
 145   for (cnt = 4; net2 != 0; net2 >>= 8)
 146     net_bytes[--cnt] = net2 & 0xff;
 147
 148   switch (cnt)
 149     {
 150     case 3:
 151       /* Class A network.  */
 152       sprintf (qbuf, "0.0.0.%u.in-addr.arpa", net_bytes[3]);
 153       break;
 154     case 2:
 155       /* Class B network.  */
 156       sprintf (qbuf, "0.0.%u.%u.in-addr.arpa", net_bytes[3], net_bytes[2]);
 157       break;
 158     case 1:
 159       /* Class C network.  */
 160       sprintf (qbuf, "0.%u.%u.%u.in-addr.arpa", net_bytes[3], net_bytes[2],
 161                net_bytes[1]);
 162       break;
 163     case 0:
 164       /* Class D - E network.  */
 165       sprintf (qbuf, "%u.%u.%u.%u.in-addr.arpa", net_bytes[3], net_bytes[2],
 166                net_bytes[1], net_bytes[0]);
 167       break;
 168     }
 169
 170   anslen = res_query (qbuf, C_IN, T_PTR, (u_char *) &net_buffer,
 171                       sizeof (querybuf));
 172   if (anslen < 0)
 173     /* Nothing found.  */
 174     return (errno == ECONNREFUSED
 175             || errno == EPFNOSUPPORT
 176             || errno == EAFNOSUPPORT)
 177       ? NSS_STATUS_UNAVAIL : NSS_STATUS_NOTFOUND;
 178
 179   status = getanswer_r (&net_buffer, anslen, result, buffer, buflen, BYADDR);
 180   if (status == NSS_STATUS_SUCCESS)
 181     {
 182       /* Strip trailing zeros.  */
 183       unsigned int u_net = net; /* Maybe net should be unsigned?  */
 184
 185       while ((u_net & 0xff) == 0 && u_net != 0)
 186         u_net >>= 8;
 187       result->n_net = u_net;
 188     }
 189
 190   return status;
 191 }
 192
 193
 194 #undef offsetof
 195 #define offsetof(Type, Member) ((size_t) &((Type *) NULL)->Member)
 196
 197 static int
 198 getanswer_r (const querybuf *answer, int anslen, struct netent *result,
 199              char *buffer, int buflen, lookup_method net_i)
 200 {
 201   /*
 202    * Find first satisfactory answer
 203    *
 204    *      answer --> +------------+  ( MESSAGE )
 205    *                 |   Header   |
 206    *                 +------------+
 207    *                 |  Question  | the question for the name server
 208    *                 +------------+
 209    *                 |   Answer   | RRs answering the question
 210    *                 +------------+
 211    *                 | Authority  | RRs pointing toward an authority
 212    *                 | Additional | RRs holding additional information
 213    *                 +------------+
 214    */
 215   struct net_data
 216   {
 217     char *aliases[MAX_NR_ALIASES];
 218     char linebuffer[0];
 219   } *net_data = (struct net_data *) buffer;
 220   int linebuflen = buflen - offsetof (struct net_data, linebuffer);
 221   const char *end_of_message = &answer->buf[anslen];
 222   const HEADER *header_pointer = &answer->hdr;
 223   /* #/records in the answer section.  */
 224   int answer_count =  ntohs (header_pointer->ancount);
 225   /* #/entries in the question section.  */
 226   int question_count = ntohs (header_pointer->qdcount);
 227   char *bp = net_data->linebuffer;
 228   const char *cp = &answer->buf[HFIXEDSZ];
 229   char **alias_pointer;
 230   int have_answer;
 231   char *ans;
 232
 233   if (question_count == 0)
 234     /* FIXME: the Sun version uses for host name lookup an additional
 235        parameter for pointing to h_errno.  this is missing here.
 236        OSF/1 has a per-thread h_errno variable.  */
 237     if (header_pointer->aa != 0)
 238       {
 239         h_errno = HOST_NOT_FOUND;
 240         return NSS_STATUS_NOTFOUND;
 241       }
 242     else
 243       {
 244         h_errno = TRY_AGAIN;
 245         return NSS_STATUS_TRYAGAIN;
 246       }
 247
 248   /* Skip the question part.  */
 249   while (question_count-- > 0)
 250     cp += __dn_skipname (cp, end_of_message) + QFIXEDSZ;
 251
 252   alias_pointer = result->n_aliases = &net_data->aliases[0];
 253   *alias_pointer = NULL;
 254   have_answer = 0;
 255   ans = NULL;
 256
 257   while (--answer_count >= 0 && cp < end_of_message)
 258     {
 259       int n = dn_expand (answer->buf, end_of_message, cp, bp, linebuflen);
 260       int type, class;
 261
 262       if (n < 0 || res_dnok (bp) == 0)
 263         break;
 264       cp += n;
 265       ans = strdupa (bp);
 266       GETSHORT (type, cp);
 267       GETSHORT (class, cp);
 268       cp += INT32SZ;            /* TTL */
 269       GETSHORT (n, cp);
 270
 271       if (class == C_IN && type == T_PTR)
 272         {
 273           n = dn_expand (answer->buf, end_of_message, cp, bp, linebuflen);
 274           if (n < 0 || !res_hnok (bp))
 275             {
 276               /* XXX What does this mean?  The original form from bind
 277                  returns NULL. Incrementing cp has no effect in any case.
 278                  What should I return here. ??? */
 279               cp += n;
 280               return NSS_STATUS_UNAVAIL;
 281             }
 282           cp += n;
 283           *alias_pointer++ = bp;
 284           bp += strlen (bp) + 1;
 285           result->n_addrtype = class == C_IN ? AF_INET : AF_UNSPEC;
 286           ++have_answer;
 287         }
 288     }
 289
 290   if (have_answer)
 291     {
 292       char *tmp;
 293       int len;
 294       char *in, *cp, *rp, *wp;
 295       int cnt, first_flag;
 296
 297       *alias_pointer = NULL;
 298       switch (net_i)
 299         {
 300         case BYADDR:
 301           result->n_name = result->n_aliases[0];
 302           result->n_net = 0L;
 303           break;
 304         case BYNAME:
 305           len = strlen (result->n_aliases[0]);
 306           tmp = (char *) alloca (len + 1);
 307           tmp[len] = 0;
 308           wp = &tmp[len - 1];
 309
 310           rp = in = result->n_aliases[0];
 311           result->n_name = ans;
 312
 313           first_flag = 1;
 314           for (cnt = 0; cnt < 4; ++cnt)
 315             {
 316               char *startp;
 317
 318               startp = rp;
 319               while (*rp != '.')
 320                 ++rp;
 321               if (rp - startp > 1 || *startp != '0' || !first_flag)
 322                 {
 323                   first_flag = 0;
 324                   if (cnt > 0)
 325                     *wp-- = '.';
 326                   cp = rp;
 327                   while (cp > startp)
 328                     *wp-- = *--cp;
 329                 }
 330               in = rp + 1;
 331             }
 332
 333           result->n_net = inet_network (wp);
 334           break;
 335         }
 336
 337       ++result->n_aliases;
 338       return NSS_STATUS_SUCCESS;
 339     }
 340
 341   /* XXX Really use global variable??? */
 342   h_errno = TRY_AGAIN;
 343   return NSS_STATUS_TRYAGAIN;
 344 }