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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_TRANSACTION_H_
#define NET_DNS_DNS_TRANSACTION_H_
#pragma once
#include <string>
#include <vector>
#include "base/memory/ref_counted.h"
#include "base/memory/scoped_ptr.h"
#include "base/timer.h"
#include "base/threading/non_thread_safe.h"
#include "net/base/completion_callback.h"
#include "net/base/ip_endpoint.h"
#include "net/base/net_export.h"
#include "net/base/net_log.h"
#include "net/base/rand_callback.h"
namespace net {
class DatagramClientSocket;
class DnsQuery;
class DnsResponse;
class DnsSession;
// Performs a single asynchronous DNS transaction over UDP,
// which consists of sending out a DNS query, waiting for a response, and
// returning the response that it matches.
class NET_EXPORT_PRIVATE DnsTransaction :
NON_EXPORTED_BASE(public base::NonThreadSafe) {
public:
typedef base::Callback<void(DnsTransaction*, int)> ResultCallback;
// Create new transaction using the parameters and state in |session|.
// Issues query for name |qname| (in DNS format) type |qtype| and class IN.
// Calls |callback| on completion or timeout.
// TODO(szym): change dependency to (IPEndPoint, Socket, DnsQuery, callback)
DnsTransaction(DnsSession* session,
const base::StringPiece& qname,
uint16 qtype,
const ResultCallback& callback,
const BoundNetLog& source_net_log);
~DnsTransaction();
const DnsQuery* query() const { return query_.get(); }
const DnsResponse* response() const { return response_.get(); }
// Starts the resolution process. Will return ERR_IO_PENDING and will
// notify the caller via |delegate|. Should only be called once.
int Start();
private:
enum State {
STATE_CONNECT,
STATE_CONNECT_COMPLETE,
STATE_SEND_QUERY,
STATE_SEND_QUERY_COMPLETE,
STATE_READ_RESPONSE,
STATE_READ_RESPONSE_COMPLETE,
STATE_NONE,
};
int DoLoop(int result);
void DoCallback(int result);
void OnIOComplete(int result);
int DoConnect();
int DoConnectComplete(int result);
int DoSendQuery();
int DoSendQueryComplete(int result);
int DoReadResponse();
int DoReadResponseComplete(int result);
// Fixed number of attempts are made to send a query and read a response,
// and at the start of each, a timer is started with increasing delays.
void StartTimer(base::TimeDelta delay);
void RevokeTimer();
void OnTimeout();
scoped_refptr<DnsSession> session_;
IPEndPoint dns_server_;
scoped_ptr<DnsQuery> query_;
ResultCallback callback_;
scoped_ptr<DnsResponse> response_;
scoped_ptr<DatagramClientSocket> socket_;
// Number of retry attempts so far.
int attempts_;
State next_state_;
base::OneShotTimer<DnsTransaction> timer_;
OldCompletionCallbackImpl<DnsTransaction> io_callback_;
BoundNetLog net_log_;
DISALLOW_COPY_AND_ASSIGN(DnsTransaction);
};
} // namespace net
#endif // NET_DNS_DNS_TRANSACTION_H_
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