1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
|
// 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 <set>
#include <string>
#include <utility>
#include <vector>
#include "base/gtest_prod_util.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 ClientSocketFactory;
class DatagramClientSocket;
class DnsQuery;
class DnsResponse;
// Performs (with fixed retries) a single asynchronous DNS transaction,
// which consists of sending out a DNS query, waiting for response, and
// parsing and returning the IP addresses that it matches.
class NET_EXPORT_PRIVATE DnsTransaction :
NON_EXPORTED_BASE(public base::NonThreadSafe) {
public:
typedef std::pair<std::string, uint16> Key;
// Interface that should implemented by DnsTransaction consumer and
// passed to |Start| method to be notified when the transaction has
// completed.
class NET_EXPORT_PRIVATE Delegate {
public:
Delegate();
virtual ~Delegate();
// A consumer of DnsTransaction should override |OnTransactionComplete|
// and call |set_delegate(this)|. The method will be called once the
// resolution has completed, results passed in as arguments.
virtual void OnTransactionComplete(
int result,
const DnsTransaction* transaction,
const IPAddressList& ip_addresses);
private:
friend class DnsTransaction;
void Attach(DnsTransaction* transaction);
void Detach(DnsTransaction* transaction);
std::set<DnsTransaction*> registered_transactions_;
DISALLOW_COPY_AND_ASSIGN(Delegate);
};
// |dns_server| is the address of the DNS server, |dns_name| is the
// hostname (in DNS format) to be resolved, |query_type| is the type of
// the query, either kDNS_A or kDNS_AAAA, |rand_int| is the PRNG used for
// generating DNS query.
DnsTransaction(const IPEndPoint& dns_server,
const std::string& dns_name,
uint16 query_type,
const RandIntCallback& rand_int,
ClientSocketFactory* socket_factory,
const BoundNetLog& source_net_log,
NetLog* net_log);
~DnsTransaction();
void SetDelegate(Delegate* delegate);
const Key& key() const { return key_; }
// Starts the resolution process. Will return ERR_IO_PENDING and will
// notify the caller via |delegate|. Should only be called once.
int Start();
private:
FRIEND_TEST_ALL_PREFIXES(DnsTransactionTest, FirstTimeoutTest);
FRIEND_TEST_ALL_PREFIXES(DnsTransactionTest, SecondTimeoutTest);
FRIEND_TEST_ALL_PREFIXES(DnsTransactionTest, ThirdTimeoutTest);
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();
// This is to be used by unit tests only.
void set_timeouts_ms(const std::vector<base::TimeDelta>& timeouts_ms);
const IPEndPoint dns_server_;
Key key_;
IPAddressList ip_addresses_;
Delegate* delegate_;
scoped_ptr<DnsQuery> query_;
scoped_ptr<DnsResponse> response_;
scoped_ptr<DatagramClientSocket> socket_;
// Number of retry attempts so far.
size_t attempts_;
// Timeouts in milliseconds.
std::vector<base::TimeDelta> timeouts_ms_;
State next_state_;
ClientSocketFactory* socket_factory_;
base::OneShotTimer<DnsTransaction> timer_;
OldCompletionCallbackImpl<DnsTransaction> io_callback_;
BoundNetLog net_log_;
DISALLOW_COPY_AND_ASSIGN(DnsTransaction);
};
} // namespace net
#endif // NET_DNS_DNS_TRANSACTION_H_
|
