resolv/nss_dns/dns-network.c

   1 /* Copyright (C) 1996, 1997, 1998, 1999, 2002 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 Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the 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    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    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 > 65536
  74 # define MAXPACKET      PACKETSZ
  75 #else
  76 # define MAXPACKET      65536
  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   int olderr = errno;
 150
 151   /* No net address lookup for IPv6 yet.  */
 152   if (type != AF_INET)
 153     return NSS_STATUS_UNAVAIL;
 154
 155   if ((_res.options & RES_INIT) == 0 && __res_ninit (&_res) == -1)
 156     return NSS_STATUS_UNAVAIL;
 157
 158   net2 = (u_int32_t) net;
 159   for (cnt = 4; net2 != 0; net2 >>= 8)
 160     net_bytes[--cnt] = net2 & 0xff;
 161
 162   switch (cnt)
 163     {
 164     case 3:
 165       /* Class A network.  */
 166       sprintf (qbuf, "0.0.0.%u.in-addr.arpa", net_bytes[3]);
 167       break;
 168     case 2:
 169       /* Class B network.  */
 170       sprintf (qbuf, "0.0.%u.%u.in-addr.arpa", net_bytes[3], net_bytes[2]);
 171       break;
 172     case 1:
 173       /* Class C network.  */
 174       sprintf (qbuf, "0.%u.%u.%u.in-addr.arpa", net_bytes[3], net_bytes[2],
 175                net_bytes[1]);
 176       break;
 177     case 0:
 178       /* Class D - E network.  */
 179       sprintf (qbuf, "%u.%u.%u.%u.in-addr.arpa", net_bytes[3], net_bytes[2],
 180                net_bytes[1], net_bytes[0]);
 181       break;
 182     }
 183
 184   anslen = res_nquery (&_res, qbuf, C_IN, T_PTR, (u_char *) &net_buffer,
 185                        sizeof (querybuf));
 186   if (anslen < 0)
 187     {
 188       /* Nothing found.  */
 189       int err = errno;
 190       __set_errno (olderr);
 191       return (err == ECONNREFUSED
 192               || err == EPFNOSUPPORT
 193               || err == EAFNOSUPPORT)
 194         ? NSS_STATUS_UNAVAIL : NSS_STATUS_NOTFOUND;
 195     }
 196
 197   status = getanswer_r (&net_buffer, anslen, result, buffer, buflen, BYADDR);
 198   if (status == NSS_STATUS_SUCCESS)
 199     {
 200       /* Strip trailing zeros.  */
 201       unsigned int u_net = net; /* Maybe net should be unsigned?  */
 202
 203       while ((u_net & 0xff) == 0 && u_net != 0)
 204         u_net >>= 8;
 205       result->n_net = u_net;
 206     }
 207
 208   return status;
 209 }
 210
 211
 212 #undef offsetof
 213 #define offsetof(Type, Member) ((size_t) &((Type *) NULL)->Member)
 214
 215 static enum nss_status
 216 getanswer_r (const querybuf *answer, int anslen, struct netent *result,
 217              char *buffer, size_t buflen, lookup_method net_i)
 218 {
 219   /*
 220    * Find first satisfactory answer
 221    *
 222    *      answer --> +------------+  ( MESSAGE )
 223    *                 |   Header   |
 224    *                 +------------+
 225    *                 |  Question  | the question for the name server
 226    *                 +------------+
 227    *                 |   Answer   | RRs answering the question
 228    *                 +------------+
 229    *                 | Authority  | RRs pointing toward an authority
 230    *                 | Additional | RRs holding additional information
 231    *                 +------------+
 232    */
 233   struct net_data
 234   {
 235     char *aliases[MAX_NR_ALIASES];
 236     char linebuffer[0];
 237   } *net_data = (struct net_data *) buffer;
 238   int linebuflen = buflen - offsetof (struct net_data, linebuffer);
 239   const char *end_of_message = &answer->buf[anslen];
 240   const HEADER *header_pointer = &answer->hdr;
 241   /* #/records in the answer section.  */
 242   int answer_count =  ntohs (header_pointer->ancount);
 243   /* #/entries in the question section.  */
 244   int question_count = ntohs (header_pointer->qdcount);
 245   char *bp = net_data->linebuffer;
 246   const char *cp = &answer->buf[HFIXEDSZ];
 247   char **alias_pointer;
 248   int have_answer;
 249   char *ans;
 250   u_char packtmp[NS_MAXCDNAME];
 251
 252   if (question_count == 0)
 253     {
 254       /* FIXME: the Sun version uses for host name lookup an additional
 255          parameter for pointing to h_errno.  this is missing here.
 256          OSF/1 has a per-thread h_errno variable.  */
 257       if (header_pointer->aa != 0)
 258         {
 259           __set_h_errno (HOST_NOT_FOUND);
 260           return NSS_STATUS_NOTFOUND;
 261         }
 262       else
 263         {
 264           __set_h_errno (TRY_AGAIN);
 265           return NSS_STATUS_TRYAGAIN;
 266         }
 267     }
 268
 269   /* Skip the question part.  */
 270   while (question_count-- > 0)
 271     cp += __dn_skipname (cp, end_of_message) + QFIXEDSZ;
 272
 273   alias_pointer = result->n_aliases = &net_data->aliases[0];
 274   *alias_pointer = NULL;
 275   have_answer = 0;
 276   ans = NULL;
 277
 278   while (--answer_count >= 0 && cp < end_of_message)
 279     {
 280       int n = dn_expand (answer->buf, end_of_message, cp, bp, linebuflen);
 281       int type, class;
 282
 283       n = __ns_name_unpack (answer->buf, end_of_message, cp,
 284                             packtmp, sizeof packtmp);
 285       if (n != -1 && __ns_name_ntop (packtmp, bp, linebuflen) == -1)
 286         {
 287           if (errno == EMSGSIZE)
 288             {
 289               errno = ERANGE;
 290               return NSS_STATUS_TRYAGAIN;
 291             }
 292
 293           n = -1;
 294         }
 295
 296       if (n > 0 && bp[0] == '.')
 297         bp[0] = '\0';
 298
 299       if (n < 0 || res_dnok (bp) == 0)
 300         break;
 301       cp += n;
 302       ans = strdupa (bp);
 303       GETSHORT (type, cp);
 304       GETSHORT (class, cp);
 305       cp += INT32SZ;            /* TTL */
 306       GETSHORT (n, cp);
 307
 308       if (class == C_IN && type == T_PTR)
 309         {
 310           n = __ns_name_unpack (answer->buf, end_of_message, cp,
 311                                 packtmp, sizeof packtmp);
 312           if (n != -1 && __ns_name_ntop (packtmp, bp, linebuflen) == -1)
 313             {
 314               if (errno == EMSGSIZE)
 315                 {
 316                   errno = ERANGE;
 317                   return NSS_STATUS_TRYAGAIN;
 318                 }
 319
 320               n = -1;
 321             }
 322
 323           if (n < 0 || !res_hnok (bp))
 324             {
 325               /* XXX What does this mean?  The original form from bind
 326                  returns NULL. Incrementing cp has no effect in any case.
 327                  What should I return here. ??? */
 328               cp += n;
 329               return NSS_STATUS_UNAVAIL;
 330             }
 331           cp += n;
 332           *alias_pointer++ = bp;
 333           n = strlen (bp) + 1;
 334           bp += n;
 335           linebuflen -= n;
 336           result->n_addrtype = class == C_IN ? AF_INET : AF_UNSPEC;
 337           ++have_answer;
 338         }
 339     }
 340
 341   if (have_answer)
 342     {
 343       char *tmp;
 344       int len;
 345       char *in, *cp, *rp, *wp;
 346       int cnt, first_flag;
 347
 348       *alias_pointer = NULL;
 349       switch (net_i)
 350         {
 351         case BYADDR:
 352           result->n_name = result->n_aliases[0];
 353           result->n_net = 0L;
 354           break;
 355         case BYNAME:
 356           len = strlen (result->n_aliases[0]);
 357           tmp = (char *) alloca (len + 1);
 358           tmp[len] = 0;
 359           wp = &tmp[len - 1];
 360
 361           rp = in = result->n_aliases[0];
 362           result->n_name = ans;
 363
 364           first_flag = 1;
 365           for (cnt = 0; cnt < 4; ++cnt)
 366             {
 367               char *startp;
 368
 369               startp = rp;
 370               while (*rp != '.')
 371                 ++rp;
 372               if (rp - startp > 1 || *startp != '0' || !first_flag)
 373                 {
 374                   first_flag = 0;
 375                   if (cnt > 0)
 376                     *wp-- = '.';
 377                   cp = rp;
 378                   while (cp > startp)
 379                     *wp-- = *--cp;
 380                 }
 381               in = rp + 1;
 382             }
 383
 384           result->n_net = inet_network (wp);
 385           break;
 386         }
 387
 388       ++result->n_aliases;
 389       return NSS_STATUS_SUCCESS;
 390     }
 391
 392   __set_h_errno (TRY_AGAIN);
 393   return NSS_STATUS_TRYAGAIN;
 394 }