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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// The sole purpose of dns_config_service_win.h is for unittests so we just
// include these headers here.
#include <winsock2.h>
#include <iphlpapi.h>
#include <memory>
#include <string>
#include <vector>
#include "base/macros.h"
#include "base/memory/free_deleter.h"
#include "base/memory/ref_counted.h"
#include "base/strings/string16.h"
#include "net/base/net_export.h"
#include "net/dns/dns_config_service.h"
// The general effort of DnsConfigServiceWin is to configure |nameservers| and
// |search| in DnsConfig. The settings are stored in the Windows registry, but
// to simplify the task we use the IP Helper API wherever possible. That API
// yields the complete and ordered |nameservers|, but to determine |search| we
// need to use the registry. On Windows 7, WMI does return the correct |search|
// but on earlier versions it is insufficient.
// Experimental evaluation of Windows behavior suggests that domain parsing is
// naive. Domain suffixes in |search| are not validated until they are appended
// to the resolved name. We attempt to replicate this behavior.
namespace net {
namespace internal {
// Converts a UTF-16 domain name to ASCII, possibly using punycode.
// Returns true if the conversion succeeds and output is not empty. In case of
// failure, |domain| might become dirty.
bool NET_EXPORT_PRIVATE ParseDomainASCII(base::StringPiece16 widestr,
std::string* domain);
// Parses |value| as search list (comma-delimited list of domain names) from
// a registry key and stores it in |out|. Returns true on success. Empty
// entries (e.g., ",,org") terminate the list. Non-ascii hostnames
// are converted to punycode.
bool NET_EXPORT_PRIVATE ParseSearchList(const base::string16& value,
std::vector<std::string>* out);
// All relevant settings read from registry and IP Helper. This isolates our
// logic from system calls and is exposed for unit tests. Keep it an aggregate
// struct for easy initialization.
struct NET_EXPORT_PRIVATE DnsSystemSettings {
// The |set| flag distinguishes between empty and unset values.
struct RegString {
bool set;
base::string16 value;
struct RegDword {
bool set;
DWORD value;
struct DevolutionSetting {
// UseDomainNameDevolution
RegDword enabled;
// DomainNameDevolutionLevel
RegDword level;
// Filled in by GetAdapterAddresses. Note that the alternative
// GetNetworkParams does not include IPv6 addresses.
std::unique_ptr<IP_ADAPTER_ADDRESSES, base::FreeDeleter> addresses;
// SOFTWARE\Policies\Microsoft\Windows NT\DNSClient\SearchList
RegString policy_search_list;
// SYSTEM\CurrentControlSet\Tcpip\Parameters\SearchList
RegString tcpip_search_list;
// SYSTEM\CurrentControlSet\Tcpip\Parameters\Domain
RegString tcpip_domain;
// SOFTWARE\Policies\Microsoft\System\DNSClient\PrimaryDnsSuffix
RegString primary_dns_suffix;
// SOFTWARE\Policies\Microsoft\Windows NT\DNSClient
DevolutionSetting policy_devolution;
// SYSTEM\CurrentControlSet\Dnscache\Parameters
DevolutionSetting dnscache_devolution;
// SYSTEM\CurrentControlSet\Tcpip\Parameters
DevolutionSetting tcpip_devolution;
// SOFTWARE\Policies\Microsoft\Windows NT\DNSClient\AppendToMultiLabelName
RegDword append_to_multi_label_name;
// True when the Name Resolution Policy Table (NRPT) has at least one rule:
// SOFTWARE\Policies\Microsoft\Windows NT\DNSClient\DnsPolicyConfig\Rule*
bool have_name_resolution_policy;
enum ConfigParseWinResult {
CONFIG_PARSE_WIN_MAX // Bounding values for enumeration.
// Fills in |dns_config| from |settings|. Exposed for tests.
ConfigParseWinResult NET_EXPORT_PRIVATE ConvertSettingsToDnsConfig(
const DnsSystemSettings& settings,
DnsConfig* dns_config);
// Service for reading and watching Windows system DNS settings. This object is
// not thread-safe and methods may perform blocking I/O so methods must be
// called on a sequence that allows blocking (i.e. base::MayBlock). It may be
// constructed on a different sequence than which it's later called on.
// WatchConfig() must be called prior to ReadConfig().
// Use DnsConfigService::CreateSystemService to use it outside of tests.
class NET_EXPORT_PRIVATE DnsConfigServiceWin : public DnsConfigService {
~DnsConfigServiceWin() override;
class Watcher;
class ConfigReader;
class HostsReader;
// DnsConfigService:
void ReadNow() override;
bool StartWatching() override;
void OnConfigChanged(bool succeeded);
void OnHostsChanged(bool succeeded);
std::unique_ptr<Watcher> watcher_;
scoped_refptr<ConfigReader> config_reader_;
scoped_refptr<HostsReader> hosts_reader_;
} // namespace internal
} // namespace net