other-licenses/android/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
  29 /*
  30  * This version of this file is derived from Android 2.3 "Gingerbread",
  31  * which contains uncredited changes by Android/Google developers.  It has
  32  * been modified in 2011 for use in the Android build of Mozilla Firefox by
  33  * Mozilla contributors (including Michael Edwards <m.k.edwards@gmail.com>,
  34  * and Steve Workman <sjhworkman@gmail.com>).
  35  * These changes are offered under the same license as the original NetBSD
  36  * file, whose copyright and license are unchanged above.
  37  */
  38
  39 #ifndef _RESOLV_CACHE_H_
  40 #define _RESOLV_CACHE_H_
  41
  42 struct resolv_cache;  /* forward */
  43
  44 /* get cache instance, can be NULL if cache is disabled
  45  * (e.g. through an environment variable) */
  46 extern struct resolv_cache*  __get_res_cache(void);
  47
  48 /* this gets called everytime we detect some changes in the DNS configuration
  49  * and will flush the cache */
  50 extern void   _resolv_cache_reset( unsigned  generation );
  51
  52 typedef enum {
  53     RESOLV_CACHE_UNSUPPORTED,  /* the cache can't handle that kind of queries */
  54                                /* or the answer buffer is too small */
  55     RESOLV_CACHE_NOTFOUND,     /* the cache doesn't know about this query */
  56     RESOLV_CACHE_FOUND         /* the cache found the answer */
  57 } ResolvCacheStatus;
  58
  59 extern ResolvCacheStatus
  60 _resolv_cache_lookup( struct resolv_cache*  cache,
  61                       const void*           query,
  62                       int                   querylen,
  63                       void*                 answer,
  64                       int                   answersize,
  65                       int                  *answerlen );
  66
  67 /* add a (query,answer) to the cache, only call if _resolv_cache_lookup
  68  * did return RESOLV_CACHE_NOTFOUND
  69  */
  70 extern void
  71 _resolv_cache_add( struct resolv_cache*  cache,
  72                    const void*           query,
  73                    int                   querylen,
  74                    const void*           answer,
  75                    int                   answerlen );
  76
  77 #endif /* _RESOLV_CACHE_H_ */