resolv/nss_dns/dns-network.c

   1 /* Copyright (C) 1996, 1997, 1998, 1999 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 not,
  17    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  * 4. Neither the name of the University nor the names of its contributors
  43  *    may be used to endorse or promote products derived from this software
  44  *    without specific prior written permission.
  45  *
  46  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  47  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  48  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  49  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  50  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  51  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  52  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  53  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  54  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  55  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  56  * SUCH DAMAGE.
  57  */
  58
  59 #include <ctype.h>
  60 #include <errno.h>
  61 #include <netdb.h>
  62 #include <stdio.h>
  63 #include <stdlib.h>
  64 #include <string.h>
  65
  66 #include "nsswitch.h"
  67 #include <arpa/inet.h>
  68
  69 /* Maximum number of aliases we allow.  */
  70 #define MAX_NR_ALIASES  48
  71
  72
  73 #if PACKETSZ > 1024
  74 #define MAXPACKET       PACKETSZ
  75 #else
  76 #define MAXPACKET       1024
  77 #endif
  78
  79
  80 typedef enum
  81 {
  82   BYADDR,
  83   BYNAME
  84 } lookup_method;
  85
  86
  87 /* We need this time later.  */
  88 typedef union querybuf
  89 {
  90   HEADER hdr;
  91   u_char buf[MAXPACKET];
  92 } querybuf;
  93
  94 /* These functions are defined in res_comp.c.  */
  95 #define NS_MAXCDNAME    255     /* maximum compressed domain name */
  96 extern int __ns_name_ntop __P ((const u_char *, char *, size_t));
  97 extern int __ns_name_unpack __P ((const u_char *, const u_char *,
  98                                   const u_char *, u_char *, size_t));
  99
 100
 101 /* Prototypes for local functions.  */
 102 static enum nss_status getanswer_r (const querybuf *answer, int anslen,
 103                                     struct netent *result, char *buffer,
 104                                     size_t buflen, lookup_method net_i);
 105
 106
 107 enum nss_status
 108 _nss_dns_getnetbyname_r (const char *name, struct netent *result,
 109                          char *buffer, size_t buflen, int *errnop,
 110                          int *herrnop)
 111 {
 112   /* Return entry for network with NAME.  */
 113   querybuf net_buffer;
 114   int anslen;
 115   char *qbuf;
 116
 117   if ((_res.options & RES_INIT) == 0 && __res_ninit (&_res) == -1)
 118     return NSS_STATUS_UNAVAIL;
 119
 120   qbuf = strdupa (name);
 121   anslen = res_nsearch (&_res, qbuf, C_IN, T_PTR, (u_char *) &net_buffer,
 122                         sizeof (querybuf));
 123   if (anslen < 0)
 124     {
 125       /* Nothing found.  */
 126       *errnop = errno;
 127       return (errno == ECONNREFUSED
 128               || errno == EPFNOSUPPORT
 129               || errno == EAFNOSUPPORT)
 130         ? NSS_STATUS_UNAVAIL : NSS_STATUS_NOTFOUND;
 131     }
 132
 133   return getanswer_r (&net_buffer, anslen, result, buffer, buflen, BYNAME);
 134 }
 135
 136
 137 enum nss_status
 138 _nss_dns_getnetbyaddr_r (uint32_t net, int type, struct netent *result,
 139                          char *buffer, size_t buflen, int *errnop,
 140                          int *herrnop)
 141 {
 142   /* Return entry for network with NAME.  */
 143   enum nss_status status;
 144   querybuf net_buffer;
 145   unsigned int net_bytes[4];
 146   char qbuf[MAXDNAME];
 147   int cnt, anslen;
 148   u_int32_t net2;
 149
 150   /* No net address lookup for IPv6 yet.  */
 151   if (type != AF_INET)
 152     return NSS_STATUS_UNAVAIL;
 153
 154   if ((_res.options & RES_INIT) == 0 && __res_ninit (&_res) == -1)
 155     return NSS_STATUS_UNAVAIL;
 156
 157   net2 = (u_int32_t) net;
 158   for (cnt = 4; net2 != 0; net2 >>= 8)
 159     net_bytes[--cnt] = net2 & 0xff;
 160
 161   switch (cnt)
 162     {
 163     case 3:
 164       /* Class A network.  */
 165       sprintf (qbuf, "0.0.0.%u.in-addr.arpa", net_bytes[3]);
 166       break;
 167     case 2:
 168       /* Class B network.  */
 169       sprintf (qbuf, "0.0.%u.%u.in-addr.arpa", net_bytes[3], net_bytes[2]);
 170       break;
 171     case 1:
 172       /* Class C network.  */
 173       sprintf (qbuf, "0.%u.%u.%u.in-addr.arpa", net_bytes[3], net_bytes[2],
 174                net_bytes[1]);
 175       break;
 176     case 0:
 177       /* Class D - E network.  */
 178       sprintf (qbuf, "%u.%u.%u.%u.in-addr.arpa", net_bytes[3], net_bytes[2],
 179                net_bytes[1], net_bytes[0]);
 180       break;
 181     }
 182
 183   anslen = res_nquery (&_res, qbuf, C_IN, T_PTR, (u_char *) &net_buffer,
 184                        sizeof (querybuf));
 185   if (anslen < 0)
 186     {
 187       /* Nothing found.  */
 188       *errnop = errno;
 189       return (errno == ECONNREFUSED
 190               || errno == EPFNOSUPPORT
 191               || errno == EAFNOSUPPORT)
 192         ? NSS_STATUS_UNAVAIL : NSS_STATUS_NOTFOUND;
 193     }
 194
 195   status = getanswer_r (&net_buffer, anslen, result, buffer, buflen, BYADDR);
 196   if (status == NSS_STATUS_SUCCESS)
 197     {
 198       /* Strip trailing zeros.  */
 199       unsigned int u_net = net; /* Maybe net should be unsigned?  */
 200
 201       while ((u_net & 0xff) == 0 && u_net != 0)
 202         u_net >>= 8;
 203       result->n_net = u_net;
 204     }
 205
 206   return status;
 207 }
 208
 209
 210 #undef offsetof
 211 #define offsetof(Type, Member) ((size_t) &((Type *) NULL)->Member)
 212
 213 static enum nss_status
 214 getanswer_r (const querybuf *answer, int anslen, struct netent *result,
 215              char *buffer, size_t buflen, lookup_method net_i)
 216 {
 217   /*
 218    * Find first satisfactory answer
 219    *
 220    *      answer --> +------------+  ( MESSAGE )
 221    *                 |   Header   |
 222    *                 +------------+
 223    *                 |  Question  | the question for the name server
 224    *                 +------------+
 225    *                 |   Answer   | RRs answering the question
 226    *                 +------------+
 227    *                 | Authority  | RRs pointing toward an authority
 228    *                 | Additional | RRs holding additional information
 229    *                 +------------+
 230    */
 231   struct net_data
 232   {
 233     char *aliases[MAX_NR_ALIASES];
 234     char linebuffer[0];
 235   } *net_data = (struct net_data *) buffer;
 236   int linebuflen = buflen - offsetof (struct net_data, linebuffer);
 237   const char *end_of_message = &answer->buf[anslen];
 238   const HEADER *header_pointer = &answer->hdr;
 239   /* #/records in the answer section.  */
 240   int answer_count =  ntohs (header_pointer->ancount);
 241   /* #/entries in the question section.  */
 242   int question_count = ntohs (header_pointer->qdcount);
 243   char *bp = net_data->linebuffer;
 244   const char *cp = &answer->buf[HFIXEDSZ];
 245   char **alias_pointer;
 246   int have_answer;
 247   char *ans;
 248   u_char packtmp[NS_MAXCDNAME];
 249
 250   if (question_count == 0)
 251     {
 252       /* FIXME: the Sun version uses for host name lookup an additional
 253          parameter for pointing to h_errno.  this is missing here.
 254          OSF/1 has a per-thread h_errno variable.  */
 255       if (header_pointer->aa != 0)
 256         {
 257           __set_h_errno (HOST_NOT_FOUND);
 258           return NSS_STATUS_NOTFOUND;
 259         }
 260       else
 261         {
 262           __set_h_errno (TRY_AGAIN);
 263           return NSS_STATUS_TRYAGAIN;
 264         }
 265     }
 266
 267   /* Skip the question part.  */
 268   while (question_count-- > 0)
 269     cp += __dn_skipname (cp, end_of_message) + QFIXEDSZ;
 270
 271   alias_pointer = result->n_aliases = &net_data->aliases[0];
 272   *alias_pointer = NULL;
 273   have_answer = 0;
 274   ans = NULL;
 275
 276   while (--answer_count >= 0 && cp < end_of_message)
 277     {
 278       int n = dn_expand (answer->buf, end_of_message, cp, bp, linebuflen);
 279       int type, class;
 280
 281       n = __ns_name_unpack (answer->buf, end_of_message, cp,
 282                             packtmp, sizeof packtmp);
 283       if (n != -1 && __ns_name_ntop (packtmp, bp, linebuflen) == -1)
 284         {
 285           if (errno == EMSGSIZE)
 286             {
 287               errno = ERANGE;
 288               return NSS_STATUS_TRYAGAIN;
 289             }
 290
 291           n = -1;
 292         }
 293
 294       if (n > 0 && bp[0] == '.')
 295         bp[0] = '\0';
 296
 297       if (n < 0 || res_dnok (bp) == 0)
 298         break;
 299       cp += n;
 300       ans = strdupa (bp);
 301       GETSHORT (type, cp);
 302       GETSHORT (class, cp);
 303       cp += INT32SZ;            /* TTL */
 304       GETSHORT (n, cp);
 305
 306       if (class == C_IN && type == T_PTR)
 307         {
 308           n = __ns_name_unpack (answer->buf, end_of_message, cp,
 309                                 packtmp, sizeof packtmp);
 310           if (n != -1 && __ns_name_ntop (packtmp, bp, linebuflen) == -1)
 311             {
 312               if (errno == EMSGSIZE)
 313                 {
 314                   errno = ERANGE;
 315                   return NSS_STATUS_TRYAGAIN;
 316                 }
 317
 318               n = -1;
 319             }
 320
 321           if (n < 0 || !res_hnok (bp))
 322             {
 323               /* XXX What does this mean?  The original form from bind
 324                  returns NULL. Incrementing cp has no effect in any case.
 325                  What should I return here. ??? */
 326               cp += n;
 327               return NSS_STATUS_UNAVAIL;
 328             }
 329           cp += n;
 330           *alias_pointer++ = bp;
 331           bp += strlen (bp) + 1;
 332           result->n_addrtype = class == C_IN ? AF_INET : AF_UNSPEC;
 333           ++have_answer;
 334         }
 335     }
 336
 337   if (have_answer)
 338     {
 339       char *tmp;
 340       int len;
 341       char *in, *cp, *rp, *wp;
 342       int cnt, first_flag;
 343
 344       *alias_pointer = NULL;
 345       switch (net_i)
 346         {
 347         case BYADDR:
 348           result->n_name = result->n_aliases[0];
 349           result->n_net = 0L;
 350           break;
 351         case BYNAME:
 352           len = strlen (result->n_aliases[0]);
 353           tmp = (char *) alloca (len + 1);
 354           tmp[len] = 0;
 355           wp = &tmp[len - 1];
 356
 357           rp = in = result->n_aliases[0];
 358           result->n_name = ans;
 359
 360           first_flag = 1;
 361           for (cnt = 0; cnt < 4; ++cnt)
 362             {
 363               char *startp;
 364
 365               startp = rp;
 366               while (*rp != '.')
 367                 ++rp;
 368               if (rp - startp > 1 || *startp != '0' || !first_flag)
 369                 {
 370                   first_flag = 0;
 371                   if (cnt > 0)
 372                     *wp-- = '.';
 373                   cp = rp;
 374                   while (cp > startp)
 375                     *wp-- = *--cp;
 376                 }
 377               in = rp + 1;
 378             }
 379
 380           result->n_net = inet_network (wp);
 381           break;
 382         }
 383
 384       ++result->n_aliases;
 385       return NSS_STATUS_SUCCESS;
 386     }
 387
 388   __set_h_errno (TRY_AGAIN);
 389   return NSS_STATUS_TRYAGAIN;
 390 }