glibc-compat/nss_dns/dns-network.c

   1 /* Copyright (C) 1996, 1997 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  * 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 <glibc-compat/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 > 65536
  78 #define MAXPACKET       PACKETSZ
  79 #else
  80 #define MAXPACKET       65536
  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 /* Prototypes for local functions.  */
 100 static enum nss_status getanswer_r (const querybuf *answer, int anslen,
 101                                     struct netent *result, char *buffer,
 102                                     size_t buflen, lookup_method net_i);
 103
 104
 105 enum nss_status
 106 _nss_dns_getnetbyname_r (const char *name, struct netent *result,
 107                          char *buffer, size_t buflen)
 108 {
 109   /* Return entry for network with NAME.  */
 110   union
 111   {
 112     querybuf *buf;
 113     u_char *ptr;
 114   } net_buffer;
 115   querybuf *orig_net_buffer;
 116   int anslen;
 117   char *qbuf;
 118   enum nss_status status;
 119
 120   if ((_res.options & RES_INIT) == 0 && res_init() == -1)
 121     return NSS_STATUS_UNAVAIL;
 122
 123   qbuf = strdupa (name);
 124
 125   net_buffer.buf = orig_net_buffer = (querybuf *) alloca (1024);
 126
 127   anslen = __libc_res_nsearch (&_res, qbuf, C_IN, T_PTR, net_buffer.buf->buf,
 128                                1024, &net_buffer.ptr);
 129   if (anslen < 0)
 130     {
 131       if (net_buffer.buf != orig_net_buffer)
 132         free (net_buffer.buf);
 133       /* Nothing found.  */
 134       return (errno == ECONNREFUSED
 135               || errno == EPFNOSUPPORT
 136               || errno == EAFNOSUPPORT)
 137               ? NSS_STATUS_UNAVAIL : NSS_STATUS_NOTFOUND;
 138     }
 139
 140   status = getanswer_r (net_buffer.buf, anslen, result, buffer, buflen, BYNAME);
 141   if (net_buffer.buf != orig_net_buffer)
 142     free (net_buffer.buf);
 143   return status;
 144 }
 145
 146
 147 enum nss_status
 148 _nss_dns_getnetbyaddr_r (long net, int type, struct netent *result,
 149                          char *buffer, size_t buflen)
 150 {
 151   /* Return entry for network with NAME.  */
 152   enum nss_status status;
 153   union
 154   {
 155     querybuf *buf;
 156     u_char *ptr;
 157   } net_buffer;
 158   querybuf *orig_net_buffer;
 159   unsigned int net_bytes[4];
 160   char qbuf[MAXDNAME];
 161   int cnt, anslen;
 162   u_int32_t net2;
 163
 164   if ((_res.options & RES_INIT) == 0 && res_init() == -1)
 165     return NSS_STATUS_UNAVAIL;
 166
 167   /* No net address lookup for IPv6 yet.  */
 168   if (type != AF_INET)
 169     return NSS_STATUS_UNAVAIL;
 170
 171   net2 = (u_int32_t) net;
 172   for (cnt = 4; net2 != 0; net2 >>= 8)
 173     net_bytes[--cnt] = net2 & 0xff;
 174
 175   switch (cnt)
 176     {
 177     case 3:
 178       /* Class A network.  */
 179       sprintf (qbuf, "0.0.0.%u.in-addr.arpa", net_bytes[3]);
 180       break;
 181     case 2:
 182       /* Class B network.  */
 183       sprintf (qbuf, "0.0.%u.%u.in-addr.arpa", net_bytes[3], net_bytes[2]);
 184       break;
 185     case 1:
 186       /* Class C network.  */
 187       sprintf (qbuf, "0.%u.%u.%u.in-addr.arpa", net_bytes[3], net_bytes[2],
 188                net_bytes[1]);
 189       break;
 190     case 0:
 191       /* Class D - E network.  */
 192       sprintf (qbuf, "%u.%u.%u.%u.in-addr.arpa", net_bytes[3], net_bytes[2],
 193                net_bytes[1], net_bytes[0]);
 194       break;
 195     }
 196
 197   net_buffer.buf = orig_net_buffer = (querybuf *) alloca (1024);
 198
 199   anslen = __libc_res_nquery (&_res, qbuf, C_IN, T_PTR, net_buffer.buf->buf,
 200                               1024, &net_buffer.ptr);
 201   if (anslen < 0)
 202     {
 203       if (net_buffer.buf != orig_net_buffer)
 204         free (net_buffer.buf);
 205       /* Nothing found.  */
 206       return (errno == ECONNREFUSED
 207               || errno == EPFNOSUPPORT
 208               || errno == EAFNOSUPPORT)
 209               ? NSS_STATUS_UNAVAIL : NSS_STATUS_NOTFOUND;
 210     }
 211
 212   status = getanswer_r (net_buffer.buf, anslen, result, buffer, buflen, BYADDR);
 213   if (net_buffer.buf != orig_net_buffer)
 214     free (net_buffer.buf);
 215   if (status == NSS_STATUS_SUCCESS)
 216     {
 217       /* Strip trailing zeros.  */
 218       unsigned int u_net = net; /* Maybe net should be unsigned?  */
 219
 220       while ((u_net & 0xff) == 0 && u_net != 0)
 221         u_net >>= 8;
 222       result->n_net = u_net;
 223     }
 224
 225   return status;
 226 }
 227
 228
 229 #undef offsetof
 230 #define offsetof(Type, Member) ((size_t) &((Type *) NULL)->Member)
 231
 232 static enum nss_status
 233 getanswer_r (const querybuf *answer, int anslen, struct netent *result,
 234              char *buffer, size_t buflen, lookup_method net_i)
 235 {
 236   /*
 237    * Find first satisfactory answer
 238    *
 239    *      answer --> +------------+  ( MESSAGE )
 240    *                 |   Header   |
 241    *                 +------------+
 242    *                 |  Question  | the question for the name server
 243    *                 +------------+
 244    *                 |   Answer   | RRs answering the question
 245    *                 +------------+
 246    *                 | Authority  | RRs pointing toward an authority
 247    *                 | Additional | RRs holding additional information
 248    *                 +------------+
 249    */
 250   struct net_data
 251   {
 252     char *aliases[MAX_NR_ALIASES];
 253     char linebuffer[0];
 254   } *net_data = (struct net_data *) buffer;
 255   int linebuflen = buflen - offsetof (struct net_data, linebuffer);
 256   const char *end_of_message = &answer->buf[anslen];
 257   const HEADER *header_pointer = &answer->hdr;
 258   /* #/records in the answer section.  */
 259   int answer_count =  ntohs (header_pointer->ancount);
 260   /* #/entries in the question section.  */
 261   int question_count = ntohs (header_pointer->qdcount);
 262   char *bp = net_data->linebuffer;
 263   const char *cp = &answer->buf[HFIXEDSZ];
 264   char **alias_pointer;
 265   int have_answer;
 266   char *ans;
 267
 268   if (question_count == 0)
 269     {
 270       /* FIXME: the Sun version uses for host name lookup an additional
 271          parameter for pointing to h_errno.  this is missing here.
 272          OSF/1 has a per-thread h_errno variable.  */
 273       if (header_pointer->aa != 0)
 274         {
 275           __set_h_errno (HOST_NOT_FOUND);
 276           return NSS_STATUS_NOTFOUND;
 277         }
 278       else
 279         {
 280           __set_h_errno (TRY_AGAIN);
 281           return NSS_STATUS_TRYAGAIN;
 282         }
 283     }
 284
 285   /* Skip the question part.  */
 286   while (question_count-- > 0)
 287     {
 288       int n = __dn_skipname (cp, end_of_message);
 289       if (n < 0 || end_of_message - (cp + n) < QFIXEDSZ)
 290        {
 291          __set_h_errno (NO_RECOVERY);
 292          return NSS_STATUS_UNAVAIL;
 293        }
 294       cp += n + QFIXEDSZ;
 295     }
 296
 297   alias_pointer = result->n_aliases = &net_data->aliases[0];
 298   *alias_pointer = NULL;
 299   have_answer = 0;
 300   ans = NULL;
 301
 302   while (--answer_count >= 0 && cp < end_of_message)
 303     {
 304       int n = dn_expand (answer->buf, end_of_message, cp, bp, linebuflen);
 305       int type, class;
 306
 307       if (n < 0 || res_dnok (bp) == 0)
 308         break;
 309       cp += n;
 310       ans = strdupa (bp);
 311       GETSHORT (type, cp);
 312       GETSHORT (class, cp);
 313       cp += INT32SZ;            /* TTL */
 314       GETSHORT (n, cp);
 315
 316       if (class == C_IN && type == T_PTR)
 317         {
 318           n = dn_expand (answer->buf, end_of_message, cp, bp, linebuflen);
 319           if (n < 0 || !res_hnok (bp))
 320             {
 321               /* XXX What does this mean?  The original form from bind
 322                  returns NULL. Incrementing cp has no effect in any case.
 323                  What should I return here. ??? */
 324               cp += n;
 325               return NSS_STATUS_UNAVAIL;
 326             }
 327           cp += n;
 328          if (alias_pointer + 2 < &net_data->aliases[MAX_NR_ALIASES])
 329            {
 330              *alias_pointer++ = bp;
 331              n = strlen (bp) + 1;
 332              bp += n;
 333              linebuflen -= n;
 334              result->n_addrtype = class == C_IN ? AF_INET : AF_UNSPEC;
 335              ++have_answer;
 336            }
 337         }
 338     }
 339
 340   if (have_answer)
 341     {
 342       *alias_pointer = NULL;
 343       switch (net_i)
 344         {
 345         case BYADDR:
 346           result->n_name = *result->n_aliases++;
 347           result->n_net = 0L;
 348           return NSS_STATUS_SUCCESS;
 349
 350         case BYNAME:
 351           {
 352             char **ap = result->n_aliases++;
 353             while (*ap != NULL)
 354               {
 355                 /* Check each alias name for being of the forms:
 356                    4.3.2.1.in-addr.arpa         = net 1.2.3.4
 357                    3.2.1.in-addr.arpa           = net 0.1.2.3
 358                    2.1.in-addr.arpa             = net 0.0.1.2
 359                    1.in-addr.arpa               = net 0.0.0.1
 360                 */
 361                 uint32_t val = 0;       /* Accumulator for n_net value.  */
 362                 unsigned int shift = 0; /* Which part we are parsing now.  */
 363                 const char *p = *ap; /* Consuming the string.  */
 364                 do
 365                   {
 366                     /* Match the leading 0 or 0[xX] base indicator.  */
 367                     unsigned int base = 10;
 368                     if (*p == '0' && p[1] != '.')
 369                       {
 370                         base = 8;
 371                         ++p;
 372                         if (*p == 'x' || *p == 'X')
 373                           {
 374                             base = 16;
 375                             ++p;
 376                             if (*p == '.')
 377                               break; /* No digit here.  Give up on alias.  */
 378                           }
 379                         if (*p == '\0')
 380                           break;
 381                       }
 382
 383                     uint32_t part = 0; /* Accumulates this part's number.  */
 384                     do
 385                       {
 386                         if (isdigit (*p) && (*p - '0' < base))
 387                           part = (part * base) + (*p - '0');
 388                         else if (base == 16 && isxdigit (*p))
 389                           part = (part << 4) + 10 + (tolower (*p) - 'a');
 390                         ++p;
 391                       } while (*p != '\0' && *p != '.');
 392
 393                     if (*p != '.')
 394                       break;    /* Bad form.  Give up on this name.  */
 395
 396                     /* Install this as the next more significant byte.  */
 397                     val |= part << shift;
 398                     shift += 8;
 399                     ++p;
 400
 401                     /* If we are out of digits now, there are two cases:
 402                        1. We are done with digits and now see "in-addr.arpa".
 403                        2. This is not the droid we are looking for.  */
 404                     if (!isdigit (*p) && !strcasecmp (p, "in-addr.arpa"))
 405                       {
 406                         result->n_net = val;
 407                         return NSS_STATUS_SUCCESS;
 408                       }
 409
 410                     /* Keep going when we have seen fewer than 4 parts.  */
 411                   } while (shift < 32);
 412               }
 413           }
 414           break;
 415         }
 416     }
 417
 418   __set_h_errno (TRY_AGAIN);
 419   return NSS_STATUS_TRYAGAIN;
 420 }