| // Copyright 2018 The Chromium OS 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 "shill/active_link_monitor.h" |
| |
| #include <string> |
| #include <vector> |
| |
| #include <base/bind.h> |
| #include <base/strings/stringprintf.h> |
| #include <base/strings/string_util.h> |
| |
| #include "shill/connection.h" |
| #include "shill/device_info.h" |
| #include "shill/event_dispatcher.h" |
| #include "shill/logging.h" |
| #include "shill/metrics.h" |
| #include "shill/net/arp_client.h" |
| #include "shill/net/arp_packet.h" |
| #include "shill/net/io_handler_factory.h" |
| #include "shill/net/ip_address.h" |
| #include "shill/net/shill_time.h" |
| |
| using base::Bind; |
| using base::Unretained; |
| using std::string; |
| |
| namespace shill { |
| |
| namespace Logging { |
| static auto kModuleLogScope = ScopeLogger::kLink; |
| static string ObjectID(const Connection* c) { |
| return c->interface_name(); |
| } |
| } // namespace Logging |
| |
| const int ActiveLinkMonitor::kDefaultTestPeriodMilliseconds = 5000; |
| const int ActiveLinkMonitor::kFailureThreshold = 5; |
| const int ActiveLinkMonitor::kFastTestPeriodMilliseconds = 200; |
| const int ActiveLinkMonitor::kMaxResponseSampleFilterDepth = 5; |
| const int ActiveLinkMonitor::kUnicastReplyReliabilityThreshold = 10; |
| |
| ActiveLinkMonitor::ActiveLinkMonitor(const ConnectionRefPtr& connection, |
| EventDispatcher* dispatcher, |
| Metrics* metrics, |
| DeviceInfo* device_info, |
| const FailureCallback& failure_callback, |
| const SuccessCallback& success_callback) |
| : connection_(connection), |
| dispatcher_(dispatcher), |
| metrics_(metrics), |
| device_info_(device_info), |
| failure_callback_(failure_callback), |
| success_callback_(success_callback), |
| // Connection is not provided when this is used as a mock for testing |
| // purpose. |
| arp_client_( |
| new ArpClient(connection ? connection->interface_index() : 0)), |
| test_period_milliseconds_(kDefaultTestPeriodMilliseconds), |
| broadcast_failure_count_(0), |
| unicast_failure_count_(0), |
| broadcast_success_count_(0), |
| unicast_success_count_(0), |
| is_unicast_(false), |
| gateway_supports_unicast_arp_(false), |
| response_sample_count_(0), |
| response_sample_bucket_(0), |
| io_handler_factory_(IOHandlerFactory::GetInstance()), |
| time_(Time::GetInstance()) {} |
| |
| ActiveLinkMonitor::~ActiveLinkMonitor() { |
| Stop(); |
| } |
| |
| bool ActiveLinkMonitor::Start(int test_period) { |
| SLOG(connection_.get(), 2) << "In " << __func__ << "."; |
| StopMonitorCycle(); |
| return StartInternal(test_period); |
| } |
| |
| void ActiveLinkMonitor::Stop() { |
| SLOG(connection_.get(), 2) << "In " << __func__ << "."; |
| // Stop current cycle. |
| StopMonitorCycle(); |
| |
| // Clear stats accumulated from previous monitor cycles. |
| local_mac_address_.Clear(); |
| gateway_mac_address_.Clear(); |
| broadcast_success_count_ = 0; |
| unicast_success_count_ = 0; |
| broadcast_failure_count_ = 0; |
| unicast_failure_count_ = 0; |
| is_unicast_ = false; |
| gateway_supports_unicast_arp_ = false; |
| response_sample_bucket_ = 0; |
| response_sample_count_ = 0; |
| } |
| |
| int ActiveLinkMonitor::GetResponseTimeMilliseconds() const { |
| return response_sample_count_ |
| ? response_sample_bucket_ / response_sample_count_ |
| : 0; |
| } |
| |
| bool ActiveLinkMonitor::IsGatewayFound() const { |
| return !gateway_mac_address_.IsZero(); |
| } |
| |
| bool ActiveLinkMonitor::StartInternal(int probe_period_milliseconds) { |
| test_period_milliseconds_ = probe_period_milliseconds; |
| if (test_period_milliseconds_ > kDefaultTestPeriodMilliseconds) { |
| LOG(WARNING) << "Long test period; UMA stats will be truncated."; |
| } |
| |
| if (!device_info_->GetMacAddress(connection_->interface_index(), |
| &local_mac_address_)) { |
| LOG(ERROR) << "Could not get local MAC address."; |
| metrics_->NotifyLinkMonitorFailure(connection_->technology(), |
| Metrics::kLinkMonitorMacAddressNotFound, |
| 0, 0, 0); |
| Stop(); |
| return false; |
| } |
| |
| if (!StartArpClient()) { |
| LOG(ERROR) << "Failed to start ARP client."; |
| metrics_->NotifyLinkMonitorFailure(connection_->technology(), |
| Metrics::kLinkMonitorClientStartFailure, |
| 0, 0, 0); |
| Stop(); |
| return false; |
| } |
| |
| if (gateway_mac_address_.IsEmpty()) { |
| gateway_mac_address_ = ByteString(local_mac_address_.GetLength()); |
| } |
| send_request_callback_.Reset( |
| Bind(&ActiveLinkMonitor::SendRequest, Unretained(this))); |
| // Post a task to send ARP request instead of calling it synchronously, to |
| // maintain consistent expectation in the case of send failures, which will |
| // always invoke failure callback. |
| dispatcher_->PostTask(FROM_HERE, send_request_callback_.callback()); |
| return true; |
| } |
| |
| void ActiveLinkMonitor::StopMonitorCycle() { |
| StopArpClient(); |
| send_request_callback_.Cancel(); |
| timerclear(&sent_request_at_); |
| } |
| |
| void ActiveLinkMonitor::AddResponseTimeSample(int response_time_milliseconds) { |
| SLOG(connection_.get(), 2) << "In " << __func__ << " with sample " |
| << response_time_milliseconds << "."; |
| metrics_->NotifyLinkMonitorResponseTimeSampleAdded( |
| connection_->technology(), response_time_milliseconds); |
| response_sample_bucket_ += response_time_milliseconds; |
| if (response_sample_count_ < kMaxResponseSampleFilterDepth) { |
| ++response_sample_count_; |
| } else { |
| response_sample_bucket_ = response_sample_bucket_ * |
| kMaxResponseSampleFilterDepth / |
| (kMaxResponseSampleFilterDepth + 1); |
| } |
| } |
| |
| // static |
| string ActiveLinkMonitor::HardwareAddressToString(const ByteString& address) { |
| std::vector<string> address_parts; |
| for (size_t i = 0; i < address.GetLength(); ++i) { |
| address_parts.push_back( |
| base::StringPrintf("%02x", address.GetConstData()[i])); |
| } |
| return base::JoinString(address_parts, ":"); |
| } |
| |
| bool ActiveLinkMonitor::StartArpClient() { |
| if (!arp_client_->StartReplyListener()) { |
| return false; |
| } |
| SLOG(connection_.get(), 4) << "Created ARP client; listening on socket " |
| << arp_client_->socket() << "."; |
| receive_response_handler_.reset(io_handler_factory_->CreateIOReadyHandler( |
| arp_client_->socket(), IOHandler::kModeInput, |
| Bind(&ActiveLinkMonitor::ReceiveResponse, Unretained(this)))); |
| return true; |
| } |
| |
| void ActiveLinkMonitor::StopArpClient() { |
| arp_client_->Stop(); |
| receive_response_handler_.reset(); |
| } |
| |
| bool ActiveLinkMonitor::AddMissedResponse() { |
| SLOG(connection_.get(), 2) << "In " << __func__ << "."; |
| AddResponseTimeSample(test_period_milliseconds_); |
| |
| if (is_unicast_) { |
| if (gateway_supports_unicast_arp_) { |
| ++unicast_failure_count_; |
| } |
| unicast_success_count_ = 0; |
| } else { |
| ++broadcast_failure_count_; |
| broadcast_success_count_ = 0; |
| } |
| |
| if (unicast_failure_count_ + broadcast_failure_count_ >= kFailureThreshold) { |
| LOG(ERROR) << "Link monitor has reached the failure threshold with " |
| << broadcast_failure_count_ << " broadcast failures and " |
| << unicast_failure_count_ << " unicast failures."; |
| failure_callback_.Run(Metrics::kLinkMonitorFailureThresholdReached, |
| broadcast_failure_count_, unicast_failure_count_); |
| Stop(); |
| return true; |
| } |
| is_unicast_ = !is_unicast_; |
| return false; |
| } |
| |
| void ActiveLinkMonitor::ReceiveResponse(int fd) { |
| SLOG(connection_.get(), 2) << "In " << __func__ << "."; |
| ArpPacket packet; |
| ByteString sender; |
| if (!arp_client_->ReceivePacket(&packet, &sender)) { |
| return; |
| } |
| |
| if (!packet.IsReply()) { |
| SLOG(connection_.get(), 4) << "This is not a reply packet. Ignoring."; |
| return; |
| } |
| |
| if (!connection_->local().address().Equals( |
| packet.remote_ip_address().address())) { |
| SLOG(connection_.get(), 4) << "Response is not for our IP address."; |
| return; |
| } |
| |
| if (!local_mac_address_.Equals(packet.remote_mac_address())) { |
| SLOG(connection_.get(), 4) << "Response is not for our MAC address."; |
| return; |
| } |
| |
| if (!connection_->gateway().address().Equals( |
| packet.local_ip_address().address())) { |
| SLOG(connection_.get(), 4) |
| << "Response is not from the gateway IP address."; |
| return; |
| } |
| |
| struct timeval now, elapsed_time; |
| time_->GetTimeMonotonic(&now); |
| timersub(&now, &sent_request_at_, &elapsed_time); |
| |
| AddResponseTimeSample(elapsed_time.tv_sec * 1000 + |
| elapsed_time.tv_usec / 1000); |
| |
| if (is_unicast_) { |
| ++unicast_success_count_; |
| unicast_failure_count_ = 0; |
| if (unicast_success_count_ >= kUnicastReplyReliabilityThreshold) { |
| SLOG_IF(Link, 2, !gateway_supports_unicast_arp_) |
| << "Gateway is now considered a reliable unicast responder. " |
| "Unicast failures will now count."; |
| gateway_supports_unicast_arp_ = true; |
| } |
| } else { |
| ++broadcast_success_count_; |
| broadcast_failure_count_ = 0; |
| } |
| |
| if (!gateway_mac_address_.Equals(packet.local_mac_address())) { |
| const ByteString& new_mac_address = packet.local_mac_address(); |
| if (!IsGatewayFound()) { |
| SLOG(connection_.get(), 2) |
| << "Found gateway at " << HardwareAddressToString(new_mac_address); |
| } else { |
| SLOG(connection_.get(), 2) << "Gateway MAC address changed."; |
| } |
| gateway_mac_address_ = new_mac_address; |
| } |
| |
| is_unicast_ = !is_unicast_; |
| |
| // Stop the current cycle, and invoke the success callback. All the |
| // accumulated stats regarding the gateway are not cleared. |
| StopMonitorCycle(); |
| success_callback_.Run(); |
| } |
| |
| void ActiveLinkMonitor::SendRequest() { |
| SLOG(connection_.get(), 2) << "In " << __func__ << "."; |
| |
| // Timeout waiting for ARP reply and exceed the failure threshold. |
| if (timerisset(&sent_request_at_) && AddMissedResponse()) { |
| return; |
| } |
| |
| ByteString destination_mac_address(gateway_mac_address_.GetLength()); |
| if (!IsGatewayFound()) { |
| // The remote MAC addess is set by convention to be all-zeroes in the |
| // ARP header if not known. The ArpClient will translate an all-zeroes |
| // remote address into a send to the broadcast (all-ones) address in |
| // the Ethernet frame header. |
| SLOG_IF(Link, 2, is_unicast_) << "Sending broadcast since " |
| << "gateway MAC is unknown"; |
| is_unicast_ = false; |
| } else if (is_unicast_) { |
| destination_mac_address = gateway_mac_address_; |
| } |
| |
| ArpPacket request(connection_->local(), connection_->gateway(), |
| local_mac_address_, destination_mac_address); |
| if (!arp_client_->TransmitRequest(request)) { |
| LOG(ERROR) << "Failed to send ARP request. Stopping."; |
| failure_callback_.Run(Metrics::kLinkMonitorTransmitFailure, |
| broadcast_failure_count_, unicast_failure_count_); |
| Stop(); |
| return; |
| } |
| |
| time_->GetTimeMonotonic(&sent_request_at_); |
| |
| dispatcher_->PostDelayedTask(FROM_HERE, send_request_callback_.callback(), |
| test_period_milliseconds_); |
| } |
| |
| } // namespace shill |