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