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