src/chrome/browser/net/dns_probe_runner.cc

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "chrome/browser/net/dns_probe_runner.h"
   6
   7 #include "base/bind.h"
   8 #include "content/public/browser/browser_thread.h"
   9 #include "net/base/address_list.h"
  10 #include "net/base/ip_endpoint.h"
  11 #include "net/base/net_errors.h"
  12 #include "net/base/net_log.h"
  13 #include "net/base/net_util.h"
  14 #include "net/base/network_change_notifier.h"
  15 #include "net/dns/dns_client.h"
  16 #include "net/dns/dns_protocol.h"
  17 #include "net/dns/dns_response.h"
  18 #include "net/dns/dns_transaction.h"
  19
  20 using base::TimeDelta;
  21 using content::BrowserThread;
  22 using net::AddressList;
  23 using net::BoundNetLog;
  24 using net::DnsClient;
  25 using net::DnsResponse;
  26 using net::DnsTransaction;
  27 using net::DnsTransactionFactory;
  28 using net::IPAddressNumber;
  29 using net::IPEndPoint;
  30 using net::NetLog;
  31 using net::NetworkChangeNotifier;
  32 using net::ParseIPLiteralToNumber;
  33
  34 namespace chrome_browser_net {
  35
  36 const char* DnsProbeRunner::kKnownGoodHostname = "google.com";
  37
  38 namespace {
  39
  40 DnsProbeRunner::Result EvaluateResponse(
  41     int net_error,
  42     const DnsResponse* response) {
  43   switch (net_error) {
  44     case net::OK:
  45       break;
  46
  47     // ERR_NAME_NOT_RESOLVED maps to NXDOMAIN, which means the server is working
  48     // but returned a wrong answer.
  49     case net::ERR_NAME_NOT_RESOLVED:
  50       return DnsProbeRunner::INCORRECT;
  51
  52     // These results mean we heard *something* from the DNS server, but it was
  53     // unsuccessful (SERVFAIL) or malformed.
  54     case net::ERR_DNS_MALFORMED_RESPONSE:
  55     case net::ERR_DNS_SERVER_REQUIRES_TCP:  // Shouldn't happen; DnsTransaction
  56                                             // will retry with TCP.
  57     case net::ERR_DNS_SERVER_FAILED:
  58     case net::ERR_DNS_SORT_ERROR:  // Can only happen if the server responds.
  59       return DnsProbeRunner::FAILING;
  60
  61     // Any other error means we never reached the DNS server in the first place.
  62     case net::ERR_DNS_TIMED_OUT:
  63     default:
  64       // Something else happened, probably at a network level.
  65       return DnsProbeRunner::UNREACHABLE;
  66   }
  67
  68   AddressList addr_list;
  69   TimeDelta ttl;
  70   DnsResponse::Result result = response->ParseToAddressList(&addr_list, &ttl);
  71
  72   if (result != DnsResponse::DNS_PARSE_OK)
  73     return DnsProbeRunner::FAILING;
  74   else if (addr_list.empty())
  75     return DnsProbeRunner::INCORRECT;
  76   else
  77     return DnsProbeRunner::CORRECT;
  78 }
  79
  80 }  // namespace
  81
  82 DnsProbeRunner::DnsProbeRunner() : result_(UNKNOWN), weak_factory_(this) {}
  83
  84 DnsProbeRunner::~DnsProbeRunner() {}
  85
  86 void DnsProbeRunner::SetClient(scoped_ptr<net::DnsClient> client) {
  87   client_ = client.Pass();
  88 }
  89
  90 void DnsProbeRunner::RunProbe(const base::Closure& callback) {
  91   DCHECK(!callback.is_null());
  92   DCHECK(client_.get());
  93   DCHECK(callback_.is_null());
  94   DCHECK(!transaction_.get());
  95
  96   callback_ = callback;
  97   DnsTransactionFactory* factory = client_->GetTransactionFactory();
  98   if (!factory) {
  99     // If the DnsTransactionFactory is NULL, then the DnsConfig is invalid, so
 100     // the runner can't run a transaction.  Return UNKNOWN asynchronously.
 101     result_ = UNKNOWN;
 102     BrowserThread::PostTask(
 103         BrowserThread::IO,
 104         FROM_HERE,
 105         base::Bind(&DnsProbeRunner::CallCallback,
 106                    weak_factory_.GetWeakPtr()));
 107     return;
 108   }
 109
 110   transaction_ = factory->CreateTransaction(
 111       kKnownGoodHostname,
 112       net::dns_protocol::kTypeA,
 113       base::Bind(&DnsProbeRunner::OnTransactionComplete,
 114                  weak_factory_.GetWeakPtr()),
 115       BoundNetLog());
 116
 117   transaction_->Start();
 118 }
 119
 120 bool DnsProbeRunner::IsRunning() const {
 121   return !callback_.is_null();
 122 }
 123
 124 void DnsProbeRunner::OnTransactionComplete(
 125     DnsTransaction* transaction,
 126     int net_error,
 127     const DnsResponse* response) {
 128   DCHECK(!callback_.is_null());
 129   DCHECK(transaction_.get());
 130   DCHECK_EQ(transaction_.get(), transaction);
 131
 132   result_ = EvaluateResponse(net_error, response);
 133   transaction_.reset();
 134
 135   BrowserThread::PostTask(
 136       BrowserThread::IO,
 137       FROM_HERE,
 138       base::Bind(&DnsProbeRunner::CallCallback,
 139                  weak_factory_.GetWeakPtr()));
 140 }
 141
 142 void DnsProbeRunner::CallCallback() {
 143   DCHECK(!callback_.is_null());
 144   DCHECK(!transaction_.get());
 145
 146   // Clear callback in case it starts a new probe immediately.
 147   const base::Closure callback = callback_;
 148   callback_.Reset();
 149   callback.Run();
 150 }
 151
 152 }  // namespace chrome_browser_net