usr/src/lib/libldap5/sources/ldap/common/getdxbyname.c

   1 #pragma ident   "%Z%%M% %I%     %E% SMI"
   2
   3 /*
   4  * The contents of this file are subject to the Netscape Public
   5  * License Version 1.1 (the "License"); you may not use this file
   6  * except in compliance with the License. You may obtain a copy of
   7  * the License at http://www.mozilla.org/NPL/
   8  *
   9  * Software distributed under the License is distributed on an "AS
  10  * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
  11  * implied. See the License for the specific language governing
  12  * rights and limitations under the License.
  13  *
  14  * The Original Code is Mozilla Communicator client code, released
  15  * March 31, 1998.
  16  *
  17  * The Initial Developer of the Original Code is Netscape
  18  * Communications Corporation. Portions created by Netscape are
  19  * Copyright (C) 1998-1999 Netscape Communications Corporation. All
  20  * Rights Reserved.
  21  *
  22  * Contributor(s):
  23  */
  24 /*
  25  *  Copyright (c) 1995 Regents of the University of Michigan.
  26  *  All rights reserved.
  27  */
  28 /*
  29  * nsldapi_getdxbyname - retrieve DX records from the DNS (from
  30  * TXT records for now)
  31  */
  32
  33 #include <stdio.h>
  34
  35 #ifdef LDAP_DNS
  36
  37 XXX not MT-safe XXX
  38
  39 #include <string.h>
  40 #include <ctype.h>
  41
  42 #ifdef macintosh
  43 #include <stdlib.h>
  44 #include "macos.h"
  45 #endif /* macintosh */
  46
  47 #ifdef _WINDOWS
  48 #include <windows.h>
  49 #endif
  50
  51 #if !defined(macintosh) && !defined(DOS) && !defined( _WINDOWS )
  52 #include <sys/types.h>
  53 #include <netinet/in.h>
  54 #include <arpa/nameser.h>
  55 #include <sys/time.h>
  56 #include <sys/types.h>
  57 #include <sys/socket.h>
  58 #include <netdb.h>
  59 #include <resolv.h>
  60 #endif
  61 #include "ldap-int.h"
  62
  63 #if defined( DOS )
  64 #include "msdos.h"
  65 #endif /* DOS */
  66
  67
  68 #ifdef NEEDPROTOS
  69 static char ** decode_answer( unsigned char *answer, int len );
  70 #else /* NEEDPROTOS */
  71 static char **decode_answer();
  72 #endif /* NEEDPROTOS */
  73
  74 extern int h_errno;
  75 extern char *h_errlist[];
  76
  77
  78 #define MAX_TO_SORT     32
  79
  80
  81 /*
  82  * nsldapi_getdxbyname - lookup DNS DX records for domain and return an ordered
  83  *      array.
  84  */
  85 char **
  86 nsldapi_getdxbyname( char *domain )
  87 {
  88     unsigned char       buf[ PACKETSZ ];
  89     char                **dxs;
  90     int                 rc;
  91
  92     LDAPDebug( LDAP_DEBUG_TRACE, "nsldapi_getdxbyname( %s )\n", domain, 0, 0 );
  93
  94     memset( buf, 0, sizeof( buf ));
  95
  96     /* XXX not MT safe XXX */
  97     if (( rc = res_search( domain, C_IN, T_TXT, buf, sizeof( buf ))) < 0
  98                 || ( dxs = decode_answer( buf, rc )) == NULL ) {
  99         /*
 100          * punt:  return list conisting of the original domain name only
 101          */
 102         if (( dxs = (char **)NSLDAPI_MALLOC( 2 * sizeof( char * ))) == NULL ||
 103                 ( dxs[ 0 ] = nsldapi_strdup( domain )) == NULL ) {
 104             if ( dxs != NULL ) {
 105                 NSLDAPI_FREE( dxs );
 106             }
 107             dxs = NULL;
 108         } else {
 109             dxs[ 1 ] = NULL;
 110         }
 111     }
 112
 113     return( dxs );
 114 }
 115
 116
 117 static char **
 118 decode_answer( unsigned char *answer, int len )
 119 {
 120     HEADER              *hp;
 121     char                buf[ 256 ], **dxs;
 122     unsigned char       *eom, *p;
 123     int                 ancount, err, rc, type, class, dx_count, rr_len;
 124     int                 dx_pref[ MAX_TO_SORT ];
 125
 126 #ifdef LDAP_DEBUG
 127     if ( ldap_debug & LDAP_DEBUG_PACKETS ) {
 128 /*      __p_query( answer );    */
 129     }
 130 #endif /* LDAP_DEBUG */
 131
 132     dxs = NULL;
 133     hp = (HEADER *)answer;
 134     eom = answer + len;
 135
 136     if ( ntohs( hp->qdcount ) != 1 ) {
 137         h_errno = NO_RECOVERY;
 138         return( NULL );
 139     }
 140
 141     ancount = ntohs( hp->ancount );
 142     if ( ancount < 1 ) {
 143         h_errno = NO_DATA;
 144         return( NULL );
 145     }
 146
 147     /*
 148      * skip over the query
 149      */
 150     p = answer + HFIXEDSZ;
 151     if (( rc = dn_expand( answer, eom, p, buf, sizeof( buf ))) < 0 ) {
 152         h_errno = NO_RECOVERY;
 153         return( NULL );
 154     }
 155     p += ( rc + QFIXEDSZ );
 156
 157     /*
 158      * pull out the answers we are interested in
 159      */
 160     err = dx_count = 0;
 161     while ( ancount > 0 && err == 0 && p < eom ) {
 162         if (( rc = dn_expand( answer, eom, p, buf, sizeof( buf ))) < 0 ) {
 163             err = NO_RECOVERY;
 164             continue;
 165         }
 166         p += rc;        /* skip over name */
 167         type = _getshort( p );
 168         p += INT16SZ;
 169         class = _getshort( p );
 170         p += INT16SZ;
 171         p += INT32SZ;           /* skip over TTL */
 172         rr_len = _getshort( p );
 173         p += INT16SZ;
 174         if ( class == C_IN && type == T_TXT ) {
 175             int         i, n, pref, txt_len;
 176             char        *q, *r;
 177
 178             q = (char *)p;
 179             while ( q < (char *)p + rr_len && err == 0 ) {
 180                 if ( *q >= 3 && strncasecmp( q + 1, "dx:", 3 ) == 0 ) {
 181                     txt_len = *q - 3;
 182                     r = q + 4;
 183                     while ( isspace( *r )) {
 184                         ++r;
 185                         --txt_len;
 186                     }
 187                     pref = 0;
 188                     while ( isdigit( *r )) {
 189                         pref *= 10;
 190                         pref += ( *r - '0' );
 191                         ++r;
 192                         --txt_len;
 193                     }
 194                     if ( dx_count < MAX_TO_SORT - 1 ) {
 195                         dx_pref[ dx_count ] = pref;
 196                     }
 197                     while ( isspace( *r )) {
 198                         ++r;
 199                         --txt_len;
 200                     }
 201                     if ( dx_count == 0 ) {
 202                         dxs = (char **)NSLDAPI_MALLOC( 2 * sizeof( char * ));
 203                     } else {
 204                         dxs = (char **)NSLDAPI_REALLOC( dxs,
 205                                 ( dx_count + 2 ) * sizeof( char * ));
 206                     }
 207                     if ( dxs == NULL || ( dxs[ dx_count ] =
 208                             (char *)NSLDAPI_CALLOC( 1, txt_len + 1 ))
 209                             == NULL ) {
 210                         err = NO_RECOVERY;
 211                         continue;
 212                     }
 213                     SAFEMEMCPY( dxs[ dx_count ], r, txt_len );
 214                     dxs[ ++dx_count ] = NULL;
 215                 }
 216                 q += ( *q + 1 );        /* move past last TXT record */
 217             }
 218         }
 219         p += rr_len;
 220     }
 221
 222     if ( err == 0 ) {
 223         if ( dx_count == 0 ) {
 224             err = NO_DATA;
 225         } else {
 226             /*
 227              * sort records based on associated preference value
 228              */
 229             int         i, j, sort_count, tmp_pref;
 230             char        *tmp_dx;
 231
 232             sort_count = ( dx_count < MAX_TO_SORT ) ? dx_count : MAX_TO_SORT;
 233             for ( i = 0; i < sort_count; ++i ) {
 234                 for ( j = i + 1; j < sort_count; ++j ) {
 235                     if ( dx_pref[ i ] > dx_pref[ j ] ) {
 236                         tmp_pref = dx_pref[ i ];
 237                         dx_pref[ i ] = dx_pref[ j ];
 238                         dx_pref[ j ] = tmp_pref;
 239                         tmp_dx = dxs[ i ];
 240                         dxs[ i ] = dxs[ j ];
 241                         dxs[ j ] = tmp_dx;
 242                     }
 243                 }
 244             }
 245         }
 246     }
 247
 248     h_errno = err;
 249     return( dxs );
 250 }
 251
 252 #endif /* LDAP_DNS */