1 /*
2  * Copyright (C) 2008 The Android Open Source Project
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  *  * Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  *  * Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in
12  *    the documentation and/or other materials provided with the
13  *    distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19  * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 #ifndef _RESOLV_CACHE_H_
29 #define _RESOLV_CACHE_H_
30 
31 #include <stddef.h>
32 #include <sys/cdefs.h>
33 
34 struct __res_state;
35 
36 /* sets the name server addresses to the provided res_state structure. The
37  * name servers are retrieved from the cache which is associated
38  * with the network to which the res_state structure is associated */
39 __LIBC_HIDDEN__
40 extern void _resolv_populate_res_for_net(struct __res_state* statp);
41 
42 typedef enum {
43     RESOLV_CACHE_UNSUPPORTED,  /* the cache can't handle that kind of queries */
44                                /* or the answer buffer is too small */
45     RESOLV_CACHE_NOTFOUND,     /* the cache doesn't know about this query */
46     RESOLV_CACHE_FOUND         /* the cache found the answer */
47 } ResolvCacheStatus;
48 
49 __LIBC_HIDDEN__
50 extern ResolvCacheStatus
51 _resolv_cache_lookup( unsigned              netid,
52                       const void*           query,
53                       int                   querylen,
54                       void*                 answer,
55                       int                   answersize,
56                       int                  *answerlen );
57 
58 /* add a (query,answer) to the cache, only call if _resolv_cache_lookup
59  * did return RESOLV_CACHE_NOTFOUND
60  */
61 __LIBC_HIDDEN__
62 extern void
63 _resolv_cache_add( unsigned              netid,
64                    const void*           query,
65                    int                   querylen,
66                    const void*           answer,
67                    int                   answerlen );
68 
69 /* Notify the cache a request failed */
70 __LIBC_HIDDEN__
71 extern void
72 _resolv_cache_query_failed( unsigned     netid,
73                    const void* query,
74                    int         querylen);
75 
76 #endif /* _RESOLV_CACHE_H_ */
77