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
148
149
150
151
152
|
// Copyright 2013 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.
#include "chrome/browser/net/dns_probe_runner.h"
#include "base/bind.h"
#include "content/public/browser/browser_thread.h"
#include "net/base/address_list.h"
#include "net/base/ip_endpoint.h"
#include "net/base/net_errors.h"
#include "net/base/net_log.h"
#include "net/base/net_util.h"
#include "net/base/network_change_notifier.h"
#include "net/dns/dns_client.h"
#include "net/dns/dns_protocol.h"
#include "net/dns/dns_response.h"
#include "net/dns/dns_transaction.h"
using base::TimeDelta;
using content::BrowserThread;
using net::AddressList;
using net::BoundNetLog;
using net::DnsClient;
using net::DnsResponse;
using net::DnsTransaction;
using net::DnsTransactionFactory;
using net::IPAddressNumber;
using net::IPEndPoint;
using net::NetLog;
using net::NetworkChangeNotifier;
using net::ParseIPLiteralToNumber;
namespace chrome_browser_net {
const char* DnsProbeRunner::kKnownGoodHostname = "google.com";
namespace {
DnsProbeRunner::Result EvaluateResponse(
int net_error,
const DnsResponse* response) {
switch (net_error) {
case net::OK:
break;
// ERR_NAME_NOT_RESOLVED maps to NXDOMAIN, which means the server is working
// but returned a wrong answer.
case net::ERR_NAME_NOT_RESOLVED:
return DnsProbeRunner::INCORRECT;
// These results mean we heard *something* from the DNS server, but it was
// unsuccessful (SERVFAIL) or malformed.
case net::ERR_DNS_MALFORMED_RESPONSE:
case net::ERR_DNS_SERVER_REQUIRES_TCP: // Shouldn't happen; DnsTransaction
// will retry with TCP.
case net::ERR_DNS_SERVER_FAILED:
case net::ERR_DNS_SORT_ERROR: // Can only happen if the server responds.
return DnsProbeRunner::FAILING;
// Any other error means we never reached the DNS server in the first place.
case net::ERR_DNS_TIMED_OUT:
default:
// Something else happened, probably at a network level.
return DnsProbeRunner::UNREACHABLE;
}
AddressList addr_list;
TimeDelta ttl;
DnsResponse::Result result = response->ParseToAddressList(&addr_list, &ttl);
if (result != DnsResponse::DNS_PARSE_OK)
return DnsProbeRunner::FAILING;
else if (addr_list.empty())
return DnsProbeRunner::INCORRECT;
else
return DnsProbeRunner::CORRECT;
}
} // namespace
DnsProbeRunner::DnsProbeRunner() : result_(UNKNOWN), weak_factory_(this) {}
DnsProbeRunner::~DnsProbeRunner() {}
void DnsProbeRunner::SetClient(scoped_ptr<net::DnsClient> client) {
client_ = client.Pass();
}
void DnsProbeRunner::RunProbe(const base::Closure& callback) {
DCHECK(!callback.is_null());
DCHECK(client_.get());
DCHECK(callback_.is_null());
DCHECK(!transaction_.get());
callback_ = callback;
DnsTransactionFactory* factory = client_->GetTransactionFactory();
if (!factory) {
// If the DnsTransactionFactory is NULL, then the DnsConfig is invalid, so
// the runner can't run a transaction. Return UNKNOWN asynchronously.
result_ = UNKNOWN;
BrowserThread::PostTask(
BrowserThread::IO,
FROM_HERE,
base::Bind(&DnsProbeRunner::CallCallback,
weak_factory_.GetWeakPtr()));
return;
}
transaction_ = factory->CreateTransaction(
kKnownGoodHostname,
net::dns_protocol::kTypeA,
base::Bind(&DnsProbeRunner::OnTransactionComplete,
weak_factory_.GetWeakPtr()),
BoundNetLog());
transaction_->Start();
}
bool DnsProbeRunner::IsRunning() const {
return !callback_.is_null();
}
void DnsProbeRunner::OnTransactionComplete(
DnsTransaction* transaction,
int net_error,
const DnsResponse* response) {
DCHECK(!callback_.is_null());
DCHECK(transaction_.get());
DCHECK_EQ(transaction_.get(), transaction);
result_ = EvaluateResponse(net_error, response);
transaction_.reset();
BrowserThread::PostTask(
BrowserThread::IO,
FROM_HERE,
base::Bind(&DnsProbeRunner::CallCallback,
weak_factory_.GetWeakPtr()));
}
void DnsProbeRunner::CallCallback() {
DCHECK(!callback_.is_null());
DCHECK(!transaction_.get());
// Clear callback in case it starts a new probe immediately.
const base::Closure callback = callback_;
callback_.Reset();
callback.Run();
}
} // namespace chrome_browser_net
|
