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