| // Copyright (c) 2012 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/link_monitor.h" |
| |
| #include <vector> |
| |
| #include <base/bind.h> |
| #include <base/stringprintf.h> |
| #include <base/string_util.h> |
| |
| #include "shill/arp_client.h" |
| #include "shill/arp_packet.h" |
| #include "shill/byte_string.h" |
| #include "shill/connection.h" |
| #include "shill/device_info.h" |
| #include "shill/event_dispatcher.h" |
| #include "shill/ip_address.h" |
| #include "shill/logging.h" |
| #include "shill/metrics.h" |
| #include "shill/shill_time.h" |
| |
| using base::Bind; |
| using base::Unretained; |
| using std::string; |
| |
| namespace shill { |
| |
| const unsigned int LinkMonitor::kTestPeriodMilliseconds = 5000; |
| const unsigned int LinkMonitor::kFailureThreshold = 5; |
| const unsigned int LinkMonitor::kMaxResponseSampleFilterDepth = 5; |
| |
| LinkMonitor::LinkMonitor(const ConnectionRefPtr &connection, |
| EventDispatcher *dispatcher, |
| Metrics *metrics, |
| DeviceInfo *device_info, |
| const FailureCallback &failure_callback) |
| : connection_(connection), |
| dispatcher_(dispatcher), |
| metrics_(metrics), |
| device_info_(device_info), |
| failure_callback_(failure_callback), |
| broadcast_failure_count_(0), |
| unicast_failure_count_(0), |
| is_unicast_(false), |
| response_sample_count_(0), |
| response_sample_bucket_(0), |
| time_(Time::GetInstance()) {} |
| |
| LinkMonitor::~LinkMonitor() { |
| Stop(); |
| } |
| |
| bool LinkMonitor::Start() { |
| Stop(); |
| |
| if (!device_info_->GetMACAddress( |
| connection_->interface_index(), &local_mac_address_)) { |
| LOG(ERROR) << "Could not get local MAC address."; |
| metrics_->NotifyLinkMonitorFailure( |
| connection_->technology(), Metrics::kLinkMonitorMacAddressNotFound); |
| Stop(); |
| return false; |
| } |
| gateway_mac_address_ = ByteString(local_mac_address_.GetLength()); |
| send_request_callback_.Reset( |
| Bind(&LinkMonitor::SendRequestTask, Unretained(this))); |
| return SendRequest(); |
| } |
| |
| void LinkMonitor::Stop() { |
| SLOG(Link, 2) << "In " << __func__ << "."; |
| local_mac_address_.Clear(); |
| gateway_mac_address_.Clear(); |
| arp_client_.reset(); |
| broadcast_failure_count_ = 0; |
| unicast_failure_count_ = 0; |
| is_unicast_ = false; |
| response_sample_bucket_ = 0; |
| response_sample_count_ = 0; |
| receive_response_handler_.reset(); |
| send_request_callback_.Cancel(); |
| timerclear(&sent_request_at_); |
| } |
| |
| unsigned int LinkMonitor::GetResponseTimeMilliseconds() { |
| return response_sample_count_ ? |
| response_sample_bucket_ / response_sample_count_ : 0; |
| } |
| |
| void LinkMonitor::AddResponseTimeSample( |
| unsigned int response_time_milliseconds) { |
| SLOG(Link, 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 LinkMonitor::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 JoinString(address_parts, ':'); |
| } |
| |
| bool LinkMonitor::CreateClient() { |
| arp_client_.reset(new ArpClient(connection_->interface_index())); |
| |
| if (!arp_client_->Start()) { |
| return false; |
| } |
| receive_response_handler_.reset( |
| dispatcher_->CreateReadyHandler( |
| arp_client_->socket(), |
| IOHandler::kModeInput, |
| Bind(&LinkMonitor::ReceiveResponse, Unretained(this)))); |
| return true; |
| } |
| |
| bool LinkMonitor::AddMissedResponse() { |
| SLOG(Link, 2) << "In " << __func__ << "."; |
| AddResponseTimeSample(kTestPeriodMilliseconds); |
| |
| if (is_unicast_) { |
| ++unicast_failure_count_; |
| } else { |
| ++broadcast_failure_count_; |
| } |
| |
| 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(); |
| Stop(); |
| metrics_->NotifyLinkMonitorFailure( |
| connection_->technology(), |
| Metrics::kLinkMonitorFailureThresholdReached); |
| return true; |
| } |
| is_unicast_ = !is_unicast_; |
| return false; |
| } |
| |
| void LinkMonitor::ReceiveResponse(int fd) { |
| SLOG(Link, 2) << "In " << __func__ << "."; |
| ArpPacket packet; |
| ByteString sender; |
| if (!arp_client_->ReceiveReply(&packet, &sender)) { |
| return; |
| } |
| |
| if (!connection_->local().Equals(packet.local_ip_address())) { |
| SLOG(Link, 4) << "Response is not for our IP address."; |
| return; |
| } |
| |
| if (!local_mac_address_.Equals(packet.local_mac_address())) { |
| SLOG(Link, 4) << "Response is not for our MAC address."; |
| return; |
| } |
| |
| if (!connection_->gateway().Equals(packet.remote_ip_address())) { |
| SLOG(Link, 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); |
| |
| receive_response_handler_.reset(); |
| arp_client_.reset(); |
| |
| if (is_unicast_) { |
| unicast_failure_count_ = 0; |
| } else { |
| broadcast_failure_count_ = 0; |
| } |
| |
| if (!gateway_mac_address_.Equals(packet.remote_mac_address())) { |
| const ByteString &new_mac_address = packet.remote_mac_address(); |
| if (gateway_mac_address_.IsZero()) { |
| SLOG(Link, 2) << "Found gateway at " |
| << HardwareAddressToString(new_mac_address); |
| } else { |
| SLOG(Link, 2) << "Gateway MAC address changed."; |
| } |
| gateway_mac_address_ = new_mac_address; |
| } |
| |
| is_unicast_ = !is_unicast_; |
| } |
| |
| bool LinkMonitor::SendRequest() { |
| SLOG(Link, 2) << "In " << __func__ << "."; |
| if (!arp_client_.get()) { |
| if (!CreateClient()) { |
| LOG(ERROR) << "Failed to start ARP client."; |
| Stop(); |
| metrics_->NotifyLinkMonitorFailure( |
| connection_->technology(), Metrics::kLinkMonitorClientStartFailure); |
| return false; |
| } |
| } else if (AddMissedResponse()) { |
| // If an ARP client is still listening, this means we have timed |
| // out reception of the ARP reply. |
| return false; |
| } else { |
| // We already have an ArpClient instance running. These aren't |
| // bound sockets in the conventional sense, and we cannot distinguish |
| // which request (from which trial, or even from which component |
| // in the local system) an ARP reply was sent in response to. |
| // Therefore we keep the already open ArpClient in the case of |
| // a non-fatal timeout. |
| } |
| |
| ByteString destination_mac_address(gateway_mac_address_.GetLength()); |
| if (gateway_mac_address_.IsZero()) { |
| // 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."; |
| Stop(); |
| metrics_->NotifyLinkMonitorFailure( |
| connection_->technology(), Metrics::kLinkMonitorTransmitFailure); |
| return false; |
| } |
| |
| time_->GetTimeMonotonic(&sent_request_at_); |
| |
| dispatcher_->PostDelayedTask(send_request_callback_.callback(), |
| kTestPeriodMilliseconds); |
| return true; |
| } |
| |
| void LinkMonitor::SendRequestTask() { |
| SendRequest(); |
| } |
| |
| } // namespace shill |