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// Copyright (c) 2011 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.
#ifndef NET_DNS_DNS_CONFIG_SERVICE_H_
#define NET_DNS_DNS_CONFIG_SERVICE_H_
#pragma once
#include <map>
#include <string>
#include <vector>
#include "base/file_path.h"
#include "base/gtest_prod_util.h"
#include "base/observer_list.h"
#include "base/threading/non_thread_safe.h"
#include "base/time.h"
#include "net/base/ip_endpoint.h" // win requires size of IPEndPoint
#include "net/base/net_export.h"
#include "net/dns/dns_hosts.h"
#include "net/dns/serial_worker.h"
namespace net {
// DnsConfig stores configuration of the system resolver.
struct NET_EXPORT_PRIVATE DnsConfig {
DnsConfig();
virtual ~DnsConfig();
bool Equals(const DnsConfig& d) const;
bool EqualsIgnoreHosts(const DnsConfig& d) const;
bool IsValid() const {
return !nameservers.empty();
}
// List of name server addresses.
std::vector<IPEndPoint> nameservers;
// Suffix search list; used on first lookup when number of dots in given name
// is less than |ndots|.
std::vector<std::string> search;
DnsHosts hosts;
// Resolver options; see man resolv.conf.
// TODO(szym): use |ndots| and |search| to determine the sequence of FQDNs
// to query given a specific name.
// TODO(szym): implement DNS Devolution for windows
// Minimum number of dots before global resolution precedes |search|.
int ndots;
// Time between retransmissions, see res_state.retrans.
base::TimeDelta timeout;
// Maximum number of retries, see res_state.retry.
int attempts;
// Round robin entries in |nameservers| for subsequent requests.
bool rotate;
// Enable EDNS0 extensions.
bool edns0;
};
// Service for watching when the system DNS settings have changed.
// Depending on the platform, watches files in /etc/ or win registry.
class NET_EXPORT_PRIVATE DnsConfigService
: NON_EXPORTED_BASE(public base::NonThreadSafe) {
public:
// Callback interface for the client. The observer is called on the same
// thread as Watch(). Observer must outlive the service.
class Observer {
public:
virtual ~Observer() {}
// Called only when |dns_config| is different from the last call.
virtual void OnConfigChanged(const DnsConfig& dns_config) = 0;
};
// Creates the platform-specific DnsConfigService.
static DnsConfigService* CreateSystemService();
DnsConfigService();
virtual ~DnsConfigService();
// Immediately starts watching system configuration for changes and attempts
// to read the configuration. For some platform implementations, the current
// thread must have an IO loop (for base::files::FilePathWatcher).
virtual void Watch() {}
// If a config is available, |observer| will immediately be called with
// OnConfigChanged.
void AddObserver(Observer* observer);
void RemoveObserver(Observer* observer);
protected:
FRIEND_TEST_ALL_PREFIXES(DnsConfigServiceTest, NotifyOnChange);
friend class DnsHostsReader;
// To be called with new config. |config|.hosts is ignored.
virtual void OnConfigRead(const DnsConfig& config);
// To be called with new hosts. Rest of the config is assumed unchanged.
virtual void OnHostsRead(const DnsHosts& hosts);
DnsConfig dns_config_;
// True after first OnConfigRead and OnHostsRead; indicate complete config.
bool have_config_;
bool have_hosts_;
ObserverList<Observer> observers_;
private:
DISALLOW_COPY_AND_ASSIGN(DnsConfigService);
};
// A WatchingFileReader that reads a HOSTS file and notifies
// DnsConfigService::OnHostsRead().
// Client should call Cancel() when |service| is going away.
class NET_EXPORT_PRIVATE DnsHostsReader
: NON_EXPORTED_BASE(public SerialWorker) {
public:
DnsHostsReader(const FilePath& path, DnsConfigService* service);
virtual void DoWork() OVERRIDE;
virtual void OnWorkFinished() OVERRIDE;
private:
virtual ~DnsHostsReader();
FilePath path_;
DnsConfigService* service_;
// Written in DoRead, read in OnReadFinished, no locking necessary.
DnsHosts dns_hosts_;
bool success_;
DISALLOW_COPY_AND_ASSIGN(DnsHostsReader);
};
} // namespace net
#endif // NET_DNS_DNS_CONFIG_SERVICE_H_
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