libc/dns/include/resolv_cache.h

   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_ */