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 <sys/cdefs.h> 32 33 struct __res_state; 34 struct resolv_cache; /* forward */ 35 36 /* gets the cache for an interface. Set ifname argument to NULL or 37 * empty buffer ('\0') to get cache for default interface. 38 * returned cache might be NULL*/ 39 __LIBC_HIDDEN__ 40 extern struct resolv_cache* __get_res_cache(const char* ifname); 41 42 /* this gets called everytime we detect some changes in the DNS configuration 43 * and will flush the cache */ 44 __LIBC_HIDDEN__ 45 extern void _resolv_cache_reset( unsigned generation ); 46 47 /* Gets the address of the n:th name server for the default interface 48 * Return length of address on success else 0. 49 * Note: The first name server is at n = 1 */ 50 __LIBC_HIDDEN__ 51 extern int _resolv_cache_get_nameserver(int n, char* addr, int addrLen); 52 53 /* Gets the address of the n:th name server for a certain interface 54 * Return length of address on success else 0. 55 * Note: The first name server is at n = 1 */ 56 __LIBC_HIDDEN__ 57 extern int _resolv_cache_get_nameserver_for_iface(const char* ifname, int n, 58 char* addr, int addrLen); 59 60 /* Gets addrinfo of the n:th name server associated with an interface. 61 * NULL is returned if no address if found. 62 * Note: The first name server is at n = 1. */ 63 __LIBC_HIDDEN__ 64 extern struct addrinfo* _resolv_cache_get_nameserver_addr_for_iface(const char* ifname, int n); 65 66 /* Gets addrinfo of the n:th name server associated with the default interface 67 * NULL is returned if no address if found. 68 * Note: The first name server is at n = 1. */ 69 __LIBC_HIDDEN__ 70 extern struct addrinfo* _resolv_cache_get_nameserver_addr(int n); 71 72 /* gets the address associated with the default interface */ 73 __LIBC_HIDDEN__ 74 extern struct in_addr* _resolv_get_addr_of_default_iface(); 75 76 /* gets the address associated with the specified interface */ 77 __LIBC_HIDDEN__ 78 extern struct in_addr* _resolv_get_addr_of_iface(const char* ifname); 79 80 /* Copy the name of the default interface to provided buffer. 81 * Return length of buffer on success on failure -1 is returned */ 82 __LIBC_HIDDEN__ 83 extern int _resolv_get_default_iface(char* buff, int buffLen); 84 85 /* sets the name server addresses to the provided res_state structure. The 86 * name servers are retrieved from the cache which is associated 87 * with the interface to which the res_state structure is associated */ 88 __LIBC_HIDDEN__ 89 extern int _resolv_populate_res_for_iface(struct __res_state* statp); 90 91 typedef enum { 92 RESOLV_CACHE_UNSUPPORTED, /* the cache can't handle that kind of queries */ 93 /* or the answer buffer is too small */ 94 RESOLV_CACHE_NOTFOUND, /* the cache doesn't know about this query */ 95 RESOLV_CACHE_FOUND /* the cache found the answer */ 96 } ResolvCacheStatus; 97 98 __LIBC_HIDDEN__ 99 extern ResolvCacheStatus 100 _resolv_cache_lookup( struct resolv_cache* cache, 101 const void* query, 102 int querylen, 103 void* answer, 104 int answersize, 105 int *answerlen ); 106 107 /* add a (query,answer) to the cache, only call if _resolv_cache_lookup 108 * did return RESOLV_CACHE_NOTFOUND 109 */ 110 __LIBC_HIDDEN__ 111 extern void 112 _resolv_cache_add( struct resolv_cache* cache, 113 const void* query, 114 int querylen, 115 const void* answer, 116 int answerlen ); 117 118 /* Notify the cache a request failed */ 119 __LIBC_HIDDEN__ 120 extern void 121 _resolv_cache_query_failed( struct resolv_cache* cache, 122 const void* query, 123 int querylen); 124 125 #endif /* _RESOLV_CACHE_H_ */ 126