/* Extended resolver state separate from struct __res_state.

   Copyright (C) 2017-2018 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

   <http://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 */