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// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "chrome/browser/local_discovery/privet_traffic_detector.h"
#include <stddef.h>
#include "base/location.h"
#include "base/macros.h"
#include "base/metrics/histogram.h"
#include "base/single_thread_task_runner.h"
#include "base/sys_byteorder.h"
#include "net/base/net_errors.h"
#include "net/base/network_interfaces.h"
#include "net/dns/dns_protocol.h"
#include "net/dns/dns_response.h"
#include "net/dns/mdns_client.h"
#include "net/log/net_log.h"
#include "net/udp/datagram_server_socket.h"
#include "net/udp/udp_server_socket.h"
namespace {
const int kMaxRestartAttempts = 10;
const char kPrivetDeviceTypeDnsString[] = "\x07_privet";
void GetNetworkListOnFileThread(
const base::Callback<void(const net::NetworkInterfaceList&)> callback) {
DCHECK_CURRENTLY_ON(content::BrowserThread::FILE);
net::NetworkInterfaceList networks;
if (!GetNetworkList(&networks, net::INCLUDE_HOST_SCOPE_VIRTUAL_INTERFACES))
return;
net::NetworkInterfaceList ip4_networks;
for (size_t i = 0; i < networks.size(); ++i) {
net::AddressFamily address_family =
net::GetAddressFamily(networks[i].address);
if (address_family == net::ADDRESS_FAMILY_IPV4 &&
networks[i].prefix_length >= 24) {
ip4_networks.push_back(networks[i]);
}
}
net::IPAddressNumber localhost_prefix(4, 0);
localhost_prefix[0] = 127;
ip4_networks.push_back(
net::NetworkInterface("lo",
"lo",
0,
net::NetworkChangeNotifier::CONNECTION_UNKNOWN,
localhost_prefix,
8,
net::IP_ADDRESS_ATTRIBUTE_NONE));
content::BrowserThread::PostTask(content::BrowserThread::IO, FROM_HERE,
base::Bind(callback, ip4_networks));
}
} // namespace
namespace local_discovery {
PrivetTrafficDetector::PrivetTrafficDetector(
net::AddressFamily address_family,
const base::Closure& on_traffic_detected)
: on_traffic_detected_(on_traffic_detected),
callback_runner_(base::MessageLoop::current()->task_runner()),
address_family_(address_family),
io_buffer_(
new net::IOBufferWithSize(net::dns_protocol::kMaxMulticastSize)),
restart_attempts_(kMaxRestartAttempts),
weak_ptr_factory_(this) {
}
void PrivetTrafficDetector::Start() {
content::BrowserThread::PostTask(
content::BrowserThread::IO,
FROM_HERE,
base::Bind(&PrivetTrafficDetector::StartOnIOThread,
weak_ptr_factory_.GetWeakPtr()));
}
PrivetTrafficDetector::~PrivetTrafficDetector() {
DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
net::NetworkChangeNotifier::RemoveNetworkChangeObserver(this);
}
void PrivetTrafficDetector::StartOnIOThread() {
DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
net::NetworkChangeNotifier::AddNetworkChangeObserver(this);
ScheduleRestart();
}
void PrivetTrafficDetector::OnNetworkChanged(
net::NetworkChangeNotifier::ConnectionType type) {
DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
restart_attempts_ = kMaxRestartAttempts;
if (type != net::NetworkChangeNotifier::CONNECTION_NONE)
ScheduleRestart();
}
void PrivetTrafficDetector::ScheduleRestart() {
DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
socket_.reset();
weak_ptr_factory_.InvalidateWeakPtrs();
content::BrowserThread::PostDelayedTask(
content::BrowserThread::FILE,
FROM_HERE,
base::Bind(&GetNetworkListOnFileThread,
base::Bind(&PrivetTrafficDetector::Restart,
weak_ptr_factory_.GetWeakPtr())),
base::TimeDelta::FromSeconds(3));
}
void PrivetTrafficDetector::Restart(const net::NetworkInterfaceList& networks) {
DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
networks_ = networks;
if (Bind() < net::OK || DoLoop(0) < net::OK) {
if ((restart_attempts_--) > 0)
ScheduleRestart();
} else {
// Reset on success.
restart_attempts_ = kMaxRestartAttempts;
}
}
int PrivetTrafficDetector::Bind() {
if (!start_time_.is_null()) {
base::TimeDelta time_delta = base::Time::Now() - start_time_;
UMA_HISTOGRAM_LONG_TIMES("LocalDiscovery.DetectorRestartTime", time_delta);
}
start_time_ = base::Time::Now();
DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
socket_.reset(new net::UDPServerSocket(NULL, net::NetLog::Source()));
net::IPEndPoint multicast_addr = net::GetMDnsIPEndPoint(address_family_);
net::IPAddressNumber address_any(multicast_addr.address().size());
net::IPEndPoint bind_endpoint(address_any, multicast_addr.port());
socket_->AllowAddressReuse();
int rv = socket_->Listen(bind_endpoint);
if (rv < net::OK)
return rv;
socket_->SetMulticastLoopbackMode(false);
return socket_->JoinGroup(multicast_addr.address());
}
bool PrivetTrafficDetector::IsSourceAcceptable() const {
for (size_t i = 0; i < networks_.size(); ++i) {
if (net::IPNumberMatchesPrefix(recv_addr_.address(), networks_[i].address,
networks_[i].prefix_length)) {
return true;
}
}
return false;
}
bool PrivetTrafficDetector::IsPrivetPacket(int rv) const {
if (rv <= static_cast<int>(sizeof(net::dns_protocol::Header)) ||
!IsSourceAcceptable()) {
return false;
}
const char* buffer_begin = io_buffer_->data();
const char* buffer_end = buffer_begin + rv;
const net::dns_protocol::Header* header =
reinterpret_cast<const net::dns_protocol::Header*>(buffer_begin);
// Check if response packet.
if (!(header->flags & base::HostToNet16(net::dns_protocol::kFlagResponse)))
return false;
const char* substring_begin = kPrivetDeviceTypeDnsString;
const char* substring_end = substring_begin +
arraysize(kPrivetDeviceTypeDnsString) - 1;
// Check for expected substring, any Privet device must include this.
return std::search(buffer_begin, buffer_end, substring_begin,
substring_end) != buffer_end;
}
int PrivetTrafficDetector::DoLoop(int rv) {
DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
do {
if (IsPrivetPacket(rv)) {
socket_.reset();
callback_runner_->PostTask(FROM_HERE, on_traffic_detected_);
base::TimeDelta time_delta = base::Time::Now() - start_time_;
UMA_HISTOGRAM_LONG_TIMES("LocalDiscovery.DetectorTriggerTime",
time_delta);
return net::OK;
}
rv = socket_->RecvFrom(
io_buffer_.get(),
io_buffer_->size(),
&recv_addr_,
base::Bind(base::IgnoreResult(&PrivetTrafficDetector::DoLoop),
base::Unretained(this)));
} while (rv > 0);
if (rv != net::ERR_IO_PENDING)
return rv;
return net::OK;
}
} // namespace local_discovery
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