128 lines
5.1 KiB
C
128 lines
5.1 KiB
C
/*
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* Copyright (C) 2008 The Android Open Source Project
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef _RESOLV_CACHE_H_
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#define _RESOLV_CACHE_H_
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#include <stddef.h>
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#include <sys/cdefs.h>
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struct __res_state;
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struct resolv_cache; /* forward */
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/* gets the cache for an interface. Set ifname argument to NULL or
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* empty buffer ('\0') to get cache for default interface.
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* returned cache might be NULL*/
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__LIBC_HIDDEN__
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extern struct resolv_cache* __get_res_cache(const char* ifname);
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/* this gets called everytime we detect some changes in the DNS configuration
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* and will flush the cache */
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__LIBC_HIDDEN__
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extern void _resolv_cache_reset( unsigned generation );
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/* Gets the address of the n:th name server for the default interface
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* Return length of address on success else 0.
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* Note: The first name server is at n = 1 */
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__LIBC_HIDDEN__
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extern int _resolv_cache_get_nameserver(int n, char* addr, int addrLen);
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/* Gets the address of the n:th name server for a certain interface
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* Return length of address on success else 0.
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* Note: The first name server is at n = 1 */
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__LIBC_HIDDEN__
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extern int _resolv_cache_get_nameserver_for_iface(const char* ifname, int n,
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char* addr, int addrLen);
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/* Gets addrinfo of the n:th name server associated with an interface.
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* NULL is returned if no address if found.
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* Note: The first name server is at n = 1. */
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__LIBC_HIDDEN__
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extern struct addrinfo* _resolv_cache_get_nameserver_addr_for_iface(const char* ifname, int n);
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/* Gets addrinfo of the n:th name server associated with the default interface
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* NULL is returned if no address if found.
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* Note: The first name server is at n = 1. */
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__LIBC_HIDDEN__
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extern struct addrinfo* _resolv_cache_get_nameserver_addr(int n);
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/* gets the address associated with the default interface */
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__LIBC_HIDDEN__
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extern struct in_addr* _resolv_get_addr_of_default_iface();
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/* gets the address associated with the specified interface */
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__LIBC_HIDDEN__
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extern struct in_addr* _resolv_get_addr_of_iface(const char* ifname);
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/* Copy the name of the default interface to the provided buffer.
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* Returns the string length of the default interface,
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* be that less or more than the buffLen, or 0 if nothing had been written */
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__LIBC_HIDDEN__
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extern size_t _resolv_get_default_iface(char* buff, size_t buffLen);
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/* sets the name server addresses to the provided res_state structure. The
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* name servers are retrieved from the cache which is associated
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* with the interface to which the res_state structure is associated */
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__LIBC_HIDDEN__
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extern void _resolv_populate_res_for_iface(struct __res_state* statp);
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typedef enum {
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RESOLV_CACHE_UNSUPPORTED, /* the cache can't handle that kind of queries */
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/* or the answer buffer is too small */
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RESOLV_CACHE_NOTFOUND, /* the cache doesn't know about this query */
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RESOLV_CACHE_FOUND /* the cache found the answer */
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} ResolvCacheStatus;
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__LIBC_HIDDEN__
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extern ResolvCacheStatus
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_resolv_cache_lookup( struct resolv_cache* cache,
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const void* query,
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int querylen,
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void* answer,
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int answersize,
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int *answerlen );
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/* add a (query,answer) to the cache, only call if _resolv_cache_lookup
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* did return RESOLV_CACHE_NOTFOUND
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*/
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__LIBC_HIDDEN__
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extern void
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_resolv_cache_add( struct resolv_cache* cache,
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const void* query,
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int querylen,
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const void* answer,
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int answerlen );
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/* Notify the cache a request failed */
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__LIBC_HIDDEN__
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extern void
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_resolv_cache_query_failed( struct resolv_cache* cache,
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const void* query,
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int querylen);
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#endif /* _RESOLV_CACHE_H_ */
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