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/*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
#ifdef LDAP_DNS
/*
* Copyright (c) 1995 Regents of the University of Michigan.
* All rights reserved.
*
* getdxbyname - retrieve DX records from the DNS (from TXT records for now)
*/
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#ifdef MACOS
#include <stdlib.h>
#include "macos.h"
#endif /* MACOS */
#if !defined(MACOS) && !defined(DOS) && !defined( _WIN32 )
#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <resolv.h>
#endif
#include "lber.h"
#include "ldap.h"
#include "ldap-private.h"
#include "ldap-int.h"
#if defined( DOS ) || defined( _WIN32 )
#include "msdos.h"
#endif /* DOS */
#ifdef NEEDPROTOS
static char ** decode_answer( unsigned char *answer, int len );
#else /* NEEDPROTOS */
static char **decode_answer();
#endif /* NEEDPROTOS */
extern int h_errno;
extern char *h_errlist[];
#define MAX_TO_SORT 32
/*
* getdxbyname - lookup DNS DX records for domain and return an ordered
* array.
*/
char **
getdxbyname( char *domain )
{
unsigned char buf[ PACKETSZ ];
char **dxs;
int rc;
Debug( LDAP_DEBUG_TRACE, "getdxbyname( %s )\n", domain, 0, 0 );
memset( buf, 0, sizeof( buf ));
if (( rc = res_search( domain, C_IN, T_TXT, buf, sizeof( buf ))) < 0
|| ( dxs = decode_answer( buf, rc )) == NULL ) {
/*
* punt: return list conisting of the original domain name only
*/
if (( dxs = (char **)malloc( 2 * sizeof( char * ))) == NULL ||
( dxs[ 0 ] = strdup( domain )) == NULL ) {
if ( dxs != NULL ) {
free( dxs );
}
dxs = NULL;
} else {
dxs[ 1 ] = NULL;
}
}
return( dxs );
}
static char **
decode_answer( unsigned char *answer, int len )
{
HEADER *hp;
char buf[ 256 ], **dxs;
unsigned char *eom, *p;
int ancount, err, rc, type, class, dx_count, rr_len;
int dx_pref[ MAX_TO_SORT ];
int _getshort( unsigned char * );
#ifdef LDAP_DEBUG
if ( ldap_debug & LDAP_DEBUG_PACKETS ) {
/* __p_query( answer ); */
}
#endif /* LDAP_DEBUG */
dxs = NULL;
hp = (HEADER *)answer;
eom = answer + len;
if ( ntohs( hp->qdcount ) != 1 ) {
h_errno = NO_RECOVERY;
return( NULL );
}
ancount = ntohs( hp->ancount );
if ( ancount < 1 ) {
h_errno = NO_DATA;
return( NULL );
}
/*
* skip over the query
*/
p = answer + HFIXEDSZ;
if (( rc = dn_expand( answer, eom, p, buf, sizeof( buf ))) < 0 ) {
h_errno = NO_RECOVERY;
return( NULL );
}
p += ( rc + QFIXEDSZ );
/*
* pull out the answers we are interested in
*/
err = dx_count = 0;
while ( ancount > 0 && err == 0 && p < eom ) {
if (( rc = dn_expand( answer, eom, p, buf, sizeof( buf ))) < 0 ) {
err = NO_RECOVERY;
continue;
}
p += rc; /* skip over name */
type = _getshort( p );
p += INT16SZ;
class = _getshort( p );
p += INT16SZ;
p += INT32SZ; /* skip over TTL */
rr_len = _getshort( p );
p += INT16SZ;
if ( class == C_IN && type == T_TXT ) {
int i, n, pref, txt_len;
char *q, *r;
q = (char *)p;
while ( q < (char *)p + rr_len && err == 0 ) {
if ( *q >= 3 && strncasecmp( q + 1, "dx:", 3 ) == 0 ) {
txt_len = *q - 3;
r = q + 4;
while ( isspace( *r )) {
++r;
--txt_len;
}
pref = 0;
while ( isdigit( *r )) {
pref *= 10;
pref += ( *r - '0' );
++r;
--txt_len;
}
if ( dx_count < MAX_TO_SORT - 1 ) {
dx_pref[ dx_count ] = pref;
}
while ( isspace( *r )) {
++r;
--txt_len;
}
if ( dx_count == 0 ) {
dxs = (char **)malloc( 2 * sizeof( char * ));
} else {
dxs = (char **)realloc( dxs,
( dx_count + 2 ) * sizeof( char * ));
}
if ( dxs == NULL || ( dxs[ dx_count ] =
(char *)calloc( 1, txt_len + 1 )) == NULL ) {
err = NO_RECOVERY;
continue;
}
memcpy( dxs[ dx_count ], r, txt_len );
dxs[ ++dx_count ] = NULL;
}
q += ( *q + 1 ); /* move past last TXT record */
}
}
p += rr_len;
}
if ( err == 0 ) {
if ( dx_count == 0 ) {
err = NO_DATA;
} else {
/*
* sort records based on associated preference value
*/
int i, j, sort_count, tmp_pref;
char *tmp_dx;
sort_count = ( dx_count < MAX_TO_SORT ) ? dx_count : MAX_TO_SORT;
for ( i = 0; i < sort_count; ++i ) {
for ( j = i + 1; j < sort_count; ++j ) {
if ( dx_pref[ i ] > dx_pref[ j ] ) {
tmp_pref = dx_pref[ i ];
dx_pref[ i ] = dx_pref[ j ];
dx_pref[ j ] = tmp_pref;
tmp_dx = dxs[ i ];
dxs[ i ] = dxs[ j ];
dxs[ j ] = tmp_dx;
}
}
}
}
}
h_errno = err;
return( dxs );
}
#endif /* LDAP_DNS */
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