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/*
* Copyright (C) 2010-2013 Tobias Brunner
* Copyright (C) 2010 Martin Willi
* HSR Hochschule fuer Technik Rapperswil
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
*
* This program 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 General Public License
* for more details.
*/
#include "android_dns_handler.h"
#include <networking/host.h>
#include <collections/linked_list.h>
#include <cutils/properties.h>
typedef struct private_android_dns_handler_t private_android_dns_handler_t;
/**
* Private data of an android_dns_handler_t object.
*/
struct private_android_dns_handler_t {
/**
* Public interface
*/
android_dns_handler_t public;
/**
* List of registered DNS servers
*/
linked_list_t *dns;
};
/**
* Prefix to be used when installing DNS servers
*/
#define DNS_PREFIX_DEFAULT "net"
/**
* Struct to store a pair of old and installed DNS servers
*/
typedef struct {
/** installed dns server */
host_t *dns;
/** old dns server */
host_t *old;
} dns_pair_t;
/**
* Destroy a pair of old and installed DNS servers
*/
static void destroy_dns_pair(dns_pair_t *this)
{
DESTROY_IF(this->dns);
DESTROY_IF(this->old);
free(this);
}
/**
* Filter pairs of DNS servers
*/
static bool filter_dns_pair(void *data, dns_pair_t **in, host_t **out)
{
*out = (*in)->dns;
return TRUE;
}
/**
* Read DNS server property with a given index
*/
static host_t *get_dns_server(private_android_dns_handler_t *this, int index)
{
host_t *dns = NULL;
char key[10], value[PROPERTY_VALUE_MAX],
*prefix = DNS_PREFIX_DEFAULT;
if (snprintf(key, sizeof(key), "%s.dns%d", prefix, index) >= sizeof(key))
{
return NULL;
}
if (property_get(key, value, NULL) > 0)
{
dns = host_create_from_string(value, 0);
}
return dns;
}
/**
* Set DNS server property with a given index
*/
static bool set_dns_server(private_android_dns_handler_t *this, int index,
host_t *dns)
{
char key[10], value[PROPERTY_VALUE_MAX],
*prefix = DNS_PREFIX_DEFAULT;
if (snprintf(key, sizeof(key), "%s.dns%d", prefix, index) >= sizeof(key))
{
return FALSE;
}
if (dns)
{
if (snprintf(value, sizeof(value), "%H", dns) >= sizeof(value))
{
return FALSE;
}
}
else
{
value[0] = '\0';
}
if (property_set(key, value) != 0)
{
return FALSE;
}
return TRUE;
}
METHOD(attribute_handler_t, handle, bool,
private_android_dns_handler_t *this, ike_sa_t *ike_sa,
configuration_attribute_type_t type, chunk_t data)
{
switch (type)
{
case INTERNAL_IP4_DNS:
{
host_t *dns;
dns_pair_t *pair;
int index;
dns = host_create_from_chunk(AF_INET, data, 0);
if (dns)
{
pair = malloc_thing(dns_pair_t);
pair->dns = dns;
index = this->dns->get_count(this->dns) + 1;
pair->old = get_dns_server(this, index);
set_dns_server(this, index, dns);
this->dns->insert_last(this->dns, pair);
return TRUE;
}
return FALSE;
}
default:
return FALSE;
}
}
METHOD(attribute_handler_t, release, void,
private_android_dns_handler_t *this, ike_sa_t *ike_sa,
configuration_attribute_type_t type, chunk_t data)
{
if (type == INTERNAL_IP4_DNS)
{
enumerator_t *enumerator;
dns_pair_t *pair;
int index;
enumerator = this->dns->create_enumerator(this->dns);
for (index = 1; enumerator->enumerate(enumerator, &pair); index++)
{
if (chunk_equals(pair->dns->get_address(pair->dns), data))
{
this->dns->remove_at(this->dns, enumerator);
set_dns_server(this, index, pair->old);
destroy_dns_pair(pair);
}
}
enumerator->destroy(enumerator);
}
}
METHOD(enumerator_t, enumerate_dns, bool,
enumerator_t *this, va_list args)
{
configuration_attribute_type_t *type;
chunk_t *data;
VA_ARGS_VGET(args, type, data);
*type = INTERNAL_IP4_DNS;
*data = chunk_empty;
this->venumerate = return_false;
return TRUE;
}
METHOD(attribute_handler_t, create_attribute_enumerator, enumerator_t *,
private_android_dns_handler_t *this, ike_sa_t *ike_sa,
linked_list_t *vips)
{
enumerator_t *enumerator;
INIT(enumerator,
.enumerate = enumerator_enumerate_default,
.venumerate = _enumerate_dns,
.destroy = (void*)free,
);
return enumerator;
}
METHOD(android_dns_handler_t, destroy, void,
private_android_dns_handler_t *this)
{
this->dns->destroy_function(this->dns, (void*)destroy_dns_pair);
free(this);
}
/**
* See header
*/
android_dns_handler_t *android_dns_handler_create()
{
private_android_dns_handler_t *this;
INIT(this,
.public = {
.handler = {
.handle = _handle,
.release = _release,
.create_attribute_enumerator = _create_attribute_enumerator,
},
.destroy = _destroy,
},
.dns = linked_list_create(),
);
return &this->public;
}
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