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