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/* Extended resolver state separate from struct __res_state.
Copyright (C) 2017-2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#ifndef RESOLV_STATE_H
#define RESOLV_STATE_H
#include <netinet/in.h>
#include <stdbool.h>
#include <stddef.h>
/* This type corresponds to members of the _res.sort_list array. */
struct resolv_sortlist_entry
{
struct in_addr addr;
uint32_t mask;
};
/* Extended resolver state associated with res_state objects. Client
code can reach this state through a struct resolv_context
object. */
struct resolv_conf
{
/* Reference counter. The object is deallocated once it reaches
zero. For internal use within resolv_conf only. */
size_t __refcount;
/* List of IPv4 and IPv6 name server addresses. */
const struct sockaddr **nameserver_list;
size_t nameserver_list_size;
/* The domain names forming the search list. */
const char *const *search_list;
size_t search_list_size;
/* IPv4 address preference rules. */
const struct resolv_sortlist_entry *sort_list;
size_t sort_list_size;
/* _res.options has type unsigned long, but we can only use 32 bits
for portability across all architectures. */
unsigned int options;
unsigned int retrans; /* Timeout. */
unsigned int retry; /* Number of times to retry. */
unsigned int ndots; /* Dots needed for initial non-search query. */
};
/* The functions below are for use by the res_init resolv.conf parser
and the struct resolv_context facility. */
struct __res_state;
struct file_change_detection;
/* Read /etc/resolv.conf and return a configuration object, or NULL if
/etc/resolv.conf cannot be read due to memory allocation errors.
If PREINIT is not NULL, some configuration values are taken from
the struct __res_state object. If CHANGE is not null, file change
detection data is written to *CHANGE, based on the state of the
file after reading it. */
struct resolv_conf *__resolv_conf_load (struct __res_state *preinit,
struct file_change_detection *change)
attribute_hidden __attribute__ ((warn_unused_result));
/* Return a configuration object for the current /etc/resolv.conf
settings, or NULL on failure. The object is cached. */
struct resolv_conf *__resolv_conf_get_current (void)
attribute_hidden __attribute__ ((warn_unused_result));
/* Return the extended resolver state for *RESP, or NULL if it cannot
be determined. A call to this function must be paired with a call
to __resolv_conf_put. */
struct resolv_conf *__resolv_conf_get (struct __res_state *) attribute_hidden;
/* Converse of __resolv_conf_get. */
void __resolv_conf_put (struct resolv_conf *) attribute_hidden;
/* Allocate a new struct resolv_conf object and copy the
pre-configured values from *INIT. Return NULL on allocation
failure. The object must be deallocated using
__resolv_conf_put. */
struct resolv_conf *__resolv_conf_allocate (const struct resolv_conf *init)
attribute_hidden __attribute__ ((nonnull (1), warn_unused_result));
/* Associate an existing extended resolver state with *RESP. Return
false on allocation failure. In addition, update *RESP with the
overlapping non-extended resolver state. */
bool __resolv_conf_attach (struct __res_state *, struct resolv_conf *)
attribute_hidden;
/* Detach the extended resolver state from *RESP. */
void __resolv_conf_detach (struct __res_state *resp) attribute_hidden;
#endif /* RESOLV_STATE_H */
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