chrome/browser/local_discovery/privet_traffic_detector.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/local_discovery/privet_traffic_detector.h"
   6
   7 #include "base/location.h"
   8 #include "base/metrics/histogram.h"
   9 #include "base/single_thread_task_runner.h"
  10 #include "base/sys_byteorder.h"
  11 #include "net/base/dns_util.h"
  12 #include "net/base/net_errors.h"
  13 #include "net/dns/dns_protocol.h"
  14 #include "net/dns/dns_response.h"
  15 #include "net/dns/mdns_client.h"
  16 #include "net/log/net_log.h"
  17 #include "net/udp/datagram_server_socket.h"
  18 #include "net/udp/udp_server_socket.h"
  19
  20 namespace {
  21
  22 const int kMaxRestartAttempts = 10;
  23 const char kPrivetDeviceTypeDnsString[] = "\x07_privet";
  24
  25 void GetNetworkListOnFileThread(
  26     const base::Callback<void(const net::NetworkInterfaceList&)> callback) {
  27   DCHECK_CURRENTLY_ON(content::BrowserThread::FILE);
  28   net::NetworkInterfaceList networks;
  29   if (!GetNetworkList(&networks, net::INCLUDE_HOST_SCOPE_VIRTUAL_INTERFACES))
  30     return;
  31
  32   net::NetworkInterfaceList ip4_networks;
  33   for (size_t i = 0; i < networks.size(); ++i) {
  34     net::AddressFamily address_family =
  35         net::GetAddressFamily(networks[i].address);
  36     if (address_family == net::ADDRESS_FAMILY_IPV4 &&
  37         networks[i].prefix_length >= 24) {
  38       ip4_networks.push_back(networks[i]);
  39     }
  40   }
  41
  42   net::IPAddressNumber localhost_prefix(4, 0);
  43   localhost_prefix[0] = 127;
  44   ip4_networks.push_back(
  45       net::NetworkInterface("lo",
  46                             "lo",
  47                             0,
  48                             net::NetworkChangeNotifier::CONNECTION_UNKNOWN,
  49                             localhost_prefix,
  50                             8,
  51                             net::IP_ADDRESS_ATTRIBUTE_NONE));
  52   content::BrowserThread::PostTask(content::BrowserThread::IO, FROM_HERE,
  53                                    base::Bind(callback, ip4_networks));
  54 }
  55
  56 }  // namespace
  57
  58 namespace local_discovery {
  59
  60 PrivetTrafficDetector::PrivetTrafficDetector(
  61     net::AddressFamily address_family,
  62     const base::Closure& on_traffic_detected)
  63     : on_traffic_detected_(on_traffic_detected),
  64       callback_runner_(base::MessageLoop::current()->task_runner()),
  65       address_family_(address_family),
  66       io_buffer_(
  67           new net::IOBufferWithSize(net::dns_protocol::kMaxMulticastSize)),
  68       restart_attempts_(kMaxRestartAttempts),
  69       weak_ptr_factory_(this) {
  70 }
  71
  72 void PrivetTrafficDetector::Start() {
  73   content::BrowserThread::PostTask(
  74       content::BrowserThread::IO,
  75       FROM_HERE,
  76       base::Bind(&PrivetTrafficDetector::StartOnIOThread,
  77                  weak_ptr_factory_.GetWeakPtr()));
  78 }
  79
  80 PrivetTrafficDetector::~PrivetTrafficDetector() {
  81   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
  82   net::NetworkChangeNotifier::RemoveNetworkChangeObserver(this);
  83 }
  84
  85 void PrivetTrafficDetector::StartOnIOThread() {
  86   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
  87   net::NetworkChangeNotifier::AddNetworkChangeObserver(this);
  88   ScheduleRestart();
  89 }
  90
  91 void PrivetTrafficDetector::OnNetworkChanged(
  92     net::NetworkChangeNotifier::ConnectionType type) {
  93   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
  94   restart_attempts_ = kMaxRestartAttempts;
  95   if (type != net::NetworkChangeNotifier::CONNECTION_NONE)
  96     ScheduleRestart();
  97 }
  98
  99 void PrivetTrafficDetector::ScheduleRestart() {
 100   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
 101   socket_.reset();
 102   weak_ptr_factory_.InvalidateWeakPtrs();
 103   content::BrowserThread::PostDelayedTask(
 104       content::BrowserThread::FILE,
 105       FROM_HERE,
 106       base::Bind(&GetNetworkListOnFileThread,
 107                  base::Bind(&PrivetTrafficDetector::Restart,
 108                             weak_ptr_factory_.GetWeakPtr())),
 109       base::TimeDelta::FromSeconds(3));
 110 }
 111
 112 void PrivetTrafficDetector::Restart(const net::NetworkInterfaceList& networks) {
 113   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
 114   networks_ = networks;
 115   if (Bind() < net::OK || DoLoop(0) < net::OK) {
 116     if ((restart_attempts_--) > 0)
 117       ScheduleRestart();
 118   } else {
 119     // Reset on success.
 120     restart_attempts_ = kMaxRestartAttempts;
 121   }
 122 }
 123
 124 int PrivetTrafficDetector::Bind() {
 125   if (!start_time_.is_null()) {
 126     base::TimeDelta time_delta = base::Time::Now() - start_time_;
 127     UMA_HISTOGRAM_LONG_TIMES("LocalDiscovery.DetectorRestartTime", time_delta);
 128   }
 129   start_time_ = base::Time::Now();
 130   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
 131   socket_.reset(new net::UDPServerSocket(NULL, net::NetLog::Source()));
 132   net::IPEndPoint multicast_addr = net::GetMDnsIPEndPoint(address_family_);
 133   net::IPAddressNumber address_any(multicast_addr.address().size());
 134   net::IPEndPoint bind_endpoint(address_any, multicast_addr.port());
 135   socket_->AllowAddressReuse();
 136   int rv = socket_->Listen(bind_endpoint);
 137   if (rv < net::OK)
 138     return rv;
 139   socket_->SetMulticastLoopbackMode(false);
 140   return socket_->JoinGroup(multicast_addr.address());
 141 }
 142
 143 bool PrivetTrafficDetector::IsSourceAcceptable() const {
 144   for (size_t i = 0; i < networks_.size(); ++i) {
 145     if (net::IPNumberMatchesPrefix(recv_addr_.address(), networks_[i].address,
 146                                    networks_[i].prefix_length)) {
 147       return true;
 148     }
 149   }
 150   return false;
 151 }
 152
 153 bool PrivetTrafficDetector::IsPrivetPacket(int rv) const {
 154   if (rv <= static_cast<int>(sizeof(net::dns_protocol::Header)) ||
 155       !IsSourceAcceptable()) {
 156     return false;
 157   }
 158
 159   const char* buffer_begin = io_buffer_->data();
 160   const char* buffer_end = buffer_begin + rv;
 161   const net::dns_protocol::Header* header =
 162       reinterpret_cast<const net::dns_protocol::Header*>(buffer_begin);
 163   // Check if response packet.
 164   if (!(header->flags & base::HostToNet16(net::dns_protocol::kFlagResponse)))
 165     return false;
 166   const char* substring_begin = kPrivetDeviceTypeDnsString;
 167   const char* substring_end = substring_begin +
 168                               arraysize(kPrivetDeviceTypeDnsString) - 1;
 169   // Check for expected substring, any Privet device must include this.
 170   return std::search(buffer_begin, buffer_end, substring_begin,
 171                      substring_end) != buffer_end;
 172 }
 173
 174 int PrivetTrafficDetector::DoLoop(int rv) {
 175   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
 176   do {
 177     if (IsPrivetPacket(rv)) {
 178       socket_.reset();
 179       callback_runner_->PostTask(FROM_HERE, on_traffic_detected_);
 180       base::TimeDelta time_delta = base::Time::Now() - start_time_;
 181       UMA_HISTOGRAM_LONG_TIMES("LocalDiscovery.DetectorTriggerTime",
 182                                time_delta);
 183       return net::OK;
 184     }
 185
 186     rv = socket_->RecvFrom(
 187         io_buffer_.get(),
 188         io_buffer_->size(),
 189         &recv_addr_,
 190         base::Bind(base::IgnoreResult(&PrivetTrafficDetector::DoLoop),
 191                    base::Unretained(this)));
 192   } while (rv > 0);
 193
 194   if (rv != net::ERR_IO_PENDING)
 195     return rv;
 196
 197   return net::OK;
 198 }
 199
 200 }  // namespace local_discovery