// 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/ethernet/ethernet.h"

#include <linux/ethtool.h>
#include <netinet/ether.h>
#include <netinet/in.h>
#include <linux/if.h>  // NOLINT - Needs definitions from netinet/ether.h
#include <linux/netdevice.h>
#include <linux/sockios.h>
#include <stdio.h>
#include <string.h>
#include <time.h>

#include <base/bind.h>
#include <base/check.h>
#include <base/files/file_path.h>
#include <base/files/file_util.h>
#include <base/location.h>
#include <base/notreached.h>
#include <base/strings/string_util.h>
#include <base/strings/stringprintf.h>
#include <chromeos/dbus/shill/dbus-constants.h>

#include "shill/adaptor_interfaces.h"
#include "shill/control_interface.h"
#include "shill/device.h"
#include "shill/device_id.h"
#include "shill/device_info.h"
#include "shill/ethernet/ethernet_provider.h"
#include "shill/ethernet/ethernet_service.h"
#include "shill/event_dispatcher.h"
#include "shill/logging.h"
#include "shill/manager.h"
#include "shill/net/rtnl_handler.h"
#include "shill/profile.h"
#include "shill/property_accessor.h"
#include "shill/refptr_types.h"
#include "shill/store_interface.h"

#if !defined(DISABLE_PPPOE)
#include "shill/pppoe/pppoe_service.h"
#endif  // DISABLE_PPPOE

#if !defined(DISABLE_WIRED_8021X)
#include "shill/eap_credentials.h"
#include "shill/eap_listener.h"
#include "shill/ethernet/ethernet_eap_provider.h"
#include "shill/supplicant/supplicant_interface_proxy_interface.h"
#include "shill/supplicant/supplicant_manager.h"
#include "shill/supplicant/supplicant_process_proxy_interface.h"
#include "shill/supplicant/wpa_supplicant.h"
#endif  // DISABLE_WIRED_8021X

using std::string;

namespace shill {

namespace Logging {
static auto kModuleLogScope = ScopeLogger::kEthernet;
static string ObjectID(const Ethernet* e) {
  return e->GetRpcIdentifier().value();
}
}  // namespace Logging

namespace {

// Path to file with |ethernet_mac0| VPD field value.
constexpr char kVpdEthernetMacFilePath[] = "/sys/firmware/vpd/ro/ethernet_mac0";
// Path to file with |dock_mac| VPD field value.
constexpr char kVpdDockMacFilePath[] = "/sys/firmware/vpd/ro/dock_mac";

bool IsValidMac(const std::string& mac_address) {
  if (mac_address.length() != 12) {
    return false;
  }
  return base::ContainsOnlyChars(mac_address, "0123456789abcdef");
}

}  // namespace

Ethernet::Ethernet(Manager* manager,
                   const string& link_name,
                   const string& mac_address,
                   int interface_index)
    : Device(manager,
             link_name,
             mac_address,
             interface_index,
             Technology::kEthernet),
      link_up_(false),
      bus_type_(GetDeviceBusType()),
#if !defined(DISABLE_WIRED_8021X)
      is_eap_authenticated_(false),
      is_eap_detected_(false),
      eap_listener_(new EapListener(interface_index)),
#endif  // DISABLE_WIRED_8021X
      sockets_(new Sockets()),
      permanent_mac_address_(GetPermanentMacAddressFromKernel()),
      weak_ptr_factory_(this) {
  PropertyStore* store = this->mutable_store();
#if !defined(DISABLE_WIRED_8021X)
  store->RegisterConstBool(kEapAuthenticationCompletedProperty,
                           &is_eap_authenticated_);
  store->RegisterConstBool(kEapAuthenticatorDetectedProperty,
                           &is_eap_detected_);
#endif  // DISABLE_WIRED_8021X
  store->RegisterConstBool(kLinkUpProperty, &link_up_);
  store->RegisterConstString(kDeviceBusTypeProperty, &bus_type_);
  store->RegisterDerivedBool(
      kPPPoEProperty,
      BoolAccessor(new CustomAccessor<Ethernet, bool>(
          this, &Ethernet::GetPPPoEMode, &Ethernet::ConfigurePPPoEMode,
          &Ethernet::ClearPPPoEMode)));
  store->RegisterDerivedString(
      kUsbEthernetMacAddressSourceProperty,
      StringAccessor(new CustomAccessor<Ethernet, std::string>(
          this, &Ethernet::GetUsbEthernetMacAddressSource, nullptr)));

#if !defined(DISABLE_WIRED_8021X)
  eap_listener_->set_request_received_callback(
      base::Bind(&Ethernet::OnEapDetected, weak_ptr_factory_.GetWeakPtr()));
#endif  // DISABLE_WIRED_8021X
  SLOG(this, 2) << "Ethernet device " << link_name << " initialized.";

  if (bus_type_ == kDeviceBusTypeUsb) {
    // Force change MAC address to |permanent_mac_address_| if
    // |mac_address_| != |permanent_mac_address_|.
    SetUsbEthernetMacAddressSource(kUsbEthernetMacAddressSourceUsbAdapterMac,
                                   nullptr, ResultCallback());
  }
}

Ethernet::~Ethernet() {}

void Ethernet::Start(Error* error,
                     const EnabledStateChangedCallback& /*callback*/) {
  rtnl_handler()->SetInterfaceFlags(interface_index(), IFF_UP, IFF_UP);
  OnEnabledStateChanged(EnabledStateChangedCallback(), Error());
  LOG(INFO) << "Registering " << link_name() << " with manager.";
  if (!service_) {
    service_ = CreateEthernetService();
  }
  RegisterService(service_);
  if (error)
    error->Reset();  // indicate immediate completion
}

void Ethernet::Stop(Error* error,
                    const EnabledStateChangedCallback& /*callback*/) {
  DeregisterService(service_);
  // EthernetProvider::DeregisterService will ResetEthernet() when the Service
  // being deregistered is the only Service remaining (instead of releasing the
  // Service entirely) so that the ethernet_any service continues to live. When
  // this happens, disassociate the EthernetService here as well.
  if (!service_->HasEthernet()) {
    service_ = nullptr;
  }
#if !defined(DISABLE_WIRED_8021X)
  StopSupplicant();
#endif  // DISABLE_WIRED_8021X
  OnEnabledStateChanged(EnabledStateChangedCallback(), Error());
  if (error)
    error->Reset();  // indicate immediate completion
}

void Ethernet::LinkEvent(unsigned int flags, unsigned int change) {
  Device::LinkEvent(flags, change);
  if ((flags & IFF_LOWER_UP) != 0 && !link_up_) {
    link_up_ = true;
    adaptor()->EmitBoolChanged(kLinkUpProperty, link_up_);
    // We SetupWakeOnLan() here, instead of in Start(), because with
    // r8139, "ethtool -s eth0 wol g" fails when no cable is plugged
    // in.
    if (service_) {
      manager()->UpdateService(service_);
      service_->OnVisibilityChanged();
    }
    SetupWakeOnLan();
#if !defined(DISABLE_WIRED_8021X)
    eap_listener_->Start();
#endif  // DISABLE_WIRED_8021X
  } else if ((flags & IFF_LOWER_UP) == 0 && link_up_) {
    link_up_ = false;
    adaptor()->EmitBoolChanged(kLinkUpProperty, link_up_);
    DropConnection();
    if (service_) {
      manager()->UpdateService(service_);
      service_->OnVisibilityChanged();
    }
#if !defined(DISABLE_WIRED_8021X)
    is_eap_detected_ = false;
    adaptor()->EmitBoolChanged(kEapAuthenticatorDetectedProperty,
                               is_eap_detected_);
    GetEapProvider()->ClearCredentialChangeCallback(this);
    SetIsEapAuthenticated(false);
    StopSupplicant();
    eap_listener_->Stop();
#endif  // DISABLE_WIRED_8021X
  }
}

bool Ethernet::Load(const StoreInterface* storage) {
  const string id = GetStorageIdentifier();
  if (!storage->ContainsGroup(id)) {
    SLOG(this, 2) << "Device is not available in the persistent store: " << id;
    return false;
  }

  bool pppoe = false;
  storage->GetBool(id, kPPPoEProperty, &pppoe);

  Error error;
  ConfigurePPPoEMode(pppoe, &error);
  if (!error.IsSuccess()) {
    LOG(WARNING) << "Error configuring PPPoE mode.  Ignoring!";
  }

  return Device::Load(storage);
}

bool Ethernet::Save(StoreInterface* storage) {
  const string id = GetStorageIdentifier();
  storage->SetBool(id, kPPPoEProperty, GetPPPoEMode(nullptr));
  return Device::Save(storage);
}

void Ethernet::ConnectTo(EthernetService* service) {
  CHECK(service_) << "Service should not be null";
  CHECK(service == service_.get()) << "Ethernet was asked to connect the "
                                   << "wrong service?";
  CHECK(!GetPPPoEMode(nullptr)) << "We should never connect in PPPoE mode!";
  if (!link_up_) {
    return;
  }
  SelectService(service);
  if (AcquireIPConfigWithLeaseName(service->GetStorageIdentifier())) {
    SetServiceState(Service::kStateConfiguring);
  } else {
    LOG(ERROR) << "Unable to acquire DHCP config.";
    SetServiceState(Service::kStateFailure);
    DestroyIPConfig();
  }
}

std::string Ethernet::GetStorageIdentifier() const {
  if (!permanent_mac_address_.empty()) {
    return "device_" + permanent_mac_address_;
  }
  return Device::GetStorageIdentifier();
}

void Ethernet::DisconnectFrom(EthernetService* service) {
  CHECK(service_) << "Service should not be null";
  CHECK(service == service_.get()) << "Ethernet was asked to disconnect the "
                                   << "wrong service?";
  DropConnection();
}

EthernetProvider* Ethernet::GetProvider() {
  EthernetProvider* provider = manager()->ethernet_provider();
  CHECK(provider);
  return provider;
}

#if !defined(DISABLE_WIRED_8021X)
void Ethernet::TryEapAuthentication() {
  try_eap_authentication_callback_.Reset(Bind(
      &Ethernet::TryEapAuthenticationTask, weak_ptr_factory_.GetWeakPtr()));
  dispatcher()->PostTask(FROM_HERE,
                         try_eap_authentication_callback_.callback());
}

void Ethernet::BSSAdded(const RpcIdentifier& path,
                        const KeyValueStore& properties) {
  NOTREACHED() << __func__ << " is not implemented for Ethernet";
}

void Ethernet::BSSRemoved(const RpcIdentifier& path) {
  NOTREACHED() << __func__ << " is not implemented for Ethernet";
}

void Ethernet::Certification(const KeyValueStore& properties) {
  string subject;
  uint32_t depth;
  if (WPASupplicant::ExtractRemoteCertification(properties, &subject, &depth)) {
    dispatcher()->PostTask(
        FROM_HERE, Bind(&Ethernet::CertificationTask,
                        weak_ptr_factory_.GetWeakPtr(), subject, depth));
  }
}

void Ethernet::EAPEvent(const string& status, const string& parameter) {
  dispatcher()->PostTask(
      FROM_HERE, Bind(&Ethernet::EAPEventTask, weak_ptr_factory_.GetWeakPtr(),
                      status, parameter));
}

void Ethernet::PropertiesChanged(const KeyValueStore& properties) {
  if (!properties.Contains<string>(WPASupplicant::kInterfacePropertyState)) {
    return;
  }
  dispatcher()->PostTask(
      FROM_HERE,
      Bind(&Ethernet::SupplicantStateChangedTask,
           weak_ptr_factory_.GetWeakPtr(),
           properties.Get<string>(WPASupplicant::kInterfacePropertyState)));
}

void Ethernet::ScanDone(const bool& /*success*/) {
  NOTREACHED() << __func__ << " is not implented for Ethernet";
}

EthernetEapProvider* Ethernet::GetEapProvider() {
  EthernetEapProvider* eap_provider = manager()->ethernet_eap_provider();
  CHECK(eap_provider);
  return eap_provider;
}

ServiceConstRefPtr Ethernet::GetEapService() {
  ServiceConstRefPtr eap_service = GetEapProvider()->service();
  CHECK(eap_service);
  return eap_service;
}

void Ethernet::OnEapDetected() {
  is_eap_detected_ = true;
  adaptor()->EmitBoolChanged(kEapAuthenticatorDetectedProperty,
                             is_eap_detected_);
  eap_listener_->Stop();
  GetEapProvider()->SetCredentialChangeCallback(
      this, base::Bind(&Ethernet::TryEapAuthentication,
                       weak_ptr_factory_.GetWeakPtr()));
  TryEapAuthentication();
}

bool Ethernet::StartSupplicant() {
  if (supplicant_interface_proxy_) {
    return true;
  }

  RpcIdentifier interface_path;
  KeyValueStore create_interface_args;
  create_interface_args.Set<string>(WPASupplicant::kInterfacePropertyName,
                                    link_name());
  create_interface_args.Set<string>(WPASupplicant::kInterfacePropertyDriver,
                                    WPASupplicant::kDriverWired);
  create_interface_args.Set<string>(WPASupplicant::kInterfacePropertyConfigFile,
                                    WPASupplicant::kSupplicantConfPath);
  if (!supplicant_process_proxy()->CreateInterface(create_interface_args,
                                                   &interface_path)) {
    // Interface might've already been created, try to retrieve it.
    if (!supplicant_process_proxy()->GetInterface(link_name(),
                                                  &interface_path)) {
      LOG(ERROR) << __func__ << ": Failed to create interface with supplicant.";
      StopSupplicant();
      return false;
    }
  }

  supplicant_interface_proxy_ =
      control_interface()->CreateSupplicantInterfaceProxy(this, interface_path);
  supplicant_interface_path_ = interface_path;
  return true;
}

bool Ethernet::StartEapAuthentication() {
  KeyValueStore params;
  GetEapService()->eap()->PopulateSupplicantProperties(&certificate_file_,
                                                       &params);
  params.Set<string>(WPASupplicant::kNetworkPropertyEapKeyManagement,
                     WPASupplicant::kKeyManagementIeee8021X);
  params.Set<uint32_t>(WPASupplicant::kNetworkPropertyEapolFlags, 0);
  params.Set<uint32_t>(WPASupplicant::kNetworkPropertyScanSSID, 0);

  if (service_) {
    service_->ClearEAPCertification();
  }
  eap_state_handler_.Reset();

  if (!supplicant_network_path_.value().empty()) {
    if (!supplicant_interface_proxy_->RemoveNetwork(supplicant_network_path_)) {
      LOG(ERROR) << "Failed to remove network: "
                 << supplicant_network_path_.value();
      return false;
    }
  }
  if (!supplicant_interface_proxy_->AddNetwork(params,
                                               &supplicant_network_path_)) {
    LOG(ERROR) << "Failed to add network";
    return false;
  }
  CHECK(!supplicant_network_path_.value().empty());

  supplicant_interface_proxy_->SelectNetwork(supplicant_network_path_);
  supplicant_interface_proxy_->EAPLogon();
  return true;
}

void Ethernet::StopSupplicant() {
  if (supplicant_interface_proxy_) {
    supplicant_interface_proxy_->EAPLogoff();
  }
  supplicant_interface_proxy_.reset();
  if (!supplicant_interface_path_.value().empty()) {
    if (!supplicant_process_proxy()->RemoveInterface(
            supplicant_interface_path_)) {
      LOG(ERROR) << __func__ << ": Failed to remove interface from supplicant.";
    }
  }
  supplicant_network_path_ = RpcIdentifier("");
  supplicant_interface_path_ = RpcIdentifier("");
  SetIsEapAuthenticated(false);
}

void Ethernet::SetIsEapAuthenticated(bool is_eap_authenticated) {
  if (is_eap_authenticated == is_eap_authenticated_) {
    return;
  }

  // If our EAP authentication state changes, we have now joined a different
  // network.  Restart the DHCP process and any other connection state.
  if (service_) {
    DisconnectFrom(service_.get());
    ConnectTo(service_.get());
  }
  is_eap_authenticated_ = is_eap_authenticated;
  adaptor()->EmitBoolChanged(kEapAuthenticationCompletedProperty,
                             is_eap_authenticated_);
}

void Ethernet::CertificationTask(const string& subject, uint32_t depth) {
  CHECK(service_) << "Ethernet " << link_name() << " " << __func__
                  << " with no service.";
  service_->AddEAPCertification(subject, depth);
}

void Ethernet::EAPEventTask(const string& status, const string& parameter) {
  LOG(INFO) << "In " << __func__ << " with status " << status << ", parameter "
            << parameter;
  Service::ConnectFailure failure = Service::kFailureNone;
  if (eap_state_handler_.ParseStatus(status, parameter, &failure)) {
    LOG(INFO) << "EAP authentication succeeded!";
    SetIsEapAuthenticated(true);
  } else if (failure != Service::Service::kFailureNone) {
    LOG(INFO) << "EAP authentication failed!";
    SetIsEapAuthenticated(false);
  }
}

void Ethernet::SupplicantStateChangedTask(const string& state) {
  LOG(INFO) << "Supplicant state changed to " << state;
}

void Ethernet::TryEapAuthenticationTask() {
  if (!GetEapService()->Is8021xConnectable()) {
    if (is_eap_authenticated_) {
      LOG(INFO) << "EAP Service lost 802.1X credentials; "
                << "terminating EAP authentication.";
    } else {
      LOG(INFO) << "EAP Service lacks 802.1X credentials; "
                << "not doing EAP authentication.";
    }
    StopSupplicant();
    return;
  }

  if (!is_eap_detected_) {
    LOG(WARNING) << "EAP authenticator not detected; "
                 << "not doing EAP authentication.";
    return;
  }
  if (!StartSupplicant()) {
    LOG(ERROR) << "Failed to start supplicant.";
    return;
  }
  StartEapAuthentication();
}

SupplicantProcessProxyInterface* Ethernet::supplicant_process_proxy() const {
  return manager()->supplicant_manager()->proxy();
}
#endif  // DISABLE_WIRED_8021X

void Ethernet::SetupWakeOnLan() {
  int sock;
  struct ifreq interface_command;
  struct ethtool_wolinfo wake_on_lan_command;

  if (link_name().length() >= sizeof(interface_command.ifr_name)) {
    LOG(WARNING) << "Interface name " << link_name()
                 << " too long: " << link_name().size()
                 << " >= " << sizeof(interface_command.ifr_name);
    return;
  }

  sock = sockets_->Socket(PF_INET, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_IP);
  if (sock < 0) {
    LOG(WARNING) << "Failed to allocate socket: " << sockets_->ErrorString()
                 << ".";
    return;
  }
  ScopedSocketCloser socket_closer(sockets_.get(), sock);

  memset(&interface_command, 0, sizeof(interface_command));
  memset(&wake_on_lan_command, 0, sizeof(wake_on_lan_command));
  wake_on_lan_command.cmd = ETHTOOL_SWOL;
  if (manager()->IsWakeOnLanEnabled()) {
    wake_on_lan_command.wolopts = WAKE_MAGIC;
  }
  interface_command.ifr_data = &wake_on_lan_command;
  memcpy(interface_command.ifr_name, link_name().data(), link_name().length());

  int res = sockets_->Ioctl(sock, SIOCETHTOOL, &interface_command);
  if (res < 0) {
    LOG(WARNING) << "Failed to enable wake-on-lan: " << sockets_->ErrorString()
                 << ".";
    return;
  }
}

bool Ethernet::ConfigurePPPoEMode(const bool& enable, Error* error) {
#if defined(DISABLE_PPPOE)
  if (enable) {
    LOG(WARNING) << "PPPoE support is not implemented.  Ignoring attempt "
                 << "to configure " << link_name();
    error->Populate(Error::kNotSupported);
  }
  return false;
#else
  if (!service_) {
    // If |service_| is null, we haven't started this Device yet.
    if (enable) {
      // Create a PPPoEService but let Start() register it.
      service_ = CreatePPPoEService();
    } else {
      // Reset |service_| and let Start() create and register a standard
      // EthernetService.
      service_ = nullptr;
    }
    return true;
  }

  EthernetServiceRefPtr service = nullptr;
  if (enable && service_->technology() != Technology::kPPPoE) {
    service = CreatePPPoEService();
    if (!manager()->HasService(service_)) {
      // |service_| is unregistered, which means the Device is not started.
      // Create a PPPoEService, but let Start() register it.
      service_ = service;
      return true;
    }
  } else if (!enable && service_->technology() == Technology::kPPPoE) {
    if (!manager()->HasService(service_)) {
      // |service_| is unregistered, which means ths Device is not started. Let
      // Start() create and register a standard EthernetService.
      service_ = nullptr;
      return true;
    }
    service = CreateEthernetService();
  } else {
    return false;
  }

  CHECK(service);
  // If |service_| has not begun to connect (i.e. this method is called prior to
  // Manager::SortServicesTask being executed and triggering an autoconnect),
  // Disconnect would return an error. We can get away with ignoring any error
  // here because DisconnectFrom does not have any failure scenarios.
  //
  // TODO(crbug.com/1003958) If/when PPPoE is redesigned, this hack will be
  // unnecessary to begin with.
  Error unused_error;
  service_->Disconnect(&unused_error, __func__);
  DeregisterService(service_);
  service_ = service;
  RegisterService(service_);

  return true;
#endif  // DISABLE_PPPOE
}

bool Ethernet::GetPPPoEMode(Error* error) {
  if (service_ == nullptr) {
    return false;
  }
  return service_->technology() == Technology::kPPPoE;
}

void Ethernet::ClearPPPoEMode(Error* error) {
  ConfigurePPPoEMode(false, error);
}

std::string Ethernet::GetUsbEthernetMacAddressSource(Error* error) {
  return usb_ethernet_mac_address_source_;
}

EthernetServiceRefPtr Ethernet::CreateEthernetService() {
  return GetProvider()->CreateService(weak_ptr_factory_.GetWeakPtr());
}

EthernetServiceRefPtr Ethernet::CreatePPPoEService() {
#if defined(DISABLE_PPPOE)
  NOTREACHED() << __func__ << " should not be called when PPPoE is disabled";
  return nullptr;
#else
  return new PPPoEService(manager(), weak_ptr_factory_.GetWeakPtr());
#endif  // DISABLE_PPPOE
}

void Ethernet::RegisterService(EthernetServiceRefPtr service) {
  if (!service) {
    return;
  }
  if (service->technology() == Technology::kPPPoE) {
    manager()->RegisterService(service);
  } else {
    GetProvider()->RegisterService(service);
  }
}

void Ethernet::DeregisterService(EthernetServiceRefPtr service) {
  if (!service) {
    return;
  }
  if (service->technology() == Technology::kPPPoE) {
    manager()->DeregisterService(service);
  } else {
    GetProvider()->DeregisterService(service);
  }
}

void Ethernet::SetUsbEthernetMacAddressSource(const std::string& source,
                                              Error* error,
                                              const ResultCallback& callback) {
  SLOG(this, 2) << __func__ << " " << source;

  if (bus_type_ != kDeviceBusTypeUsb) {
    Error::PopulateAndLog(FROM_HERE, error, Error::kNotSupported,
                          "Not supported for non-USB devices: " + bus_type_);
    return;
  }

  std::string new_mac_address;
  if (source == kUsbEthernetMacAddressSourceDesignatedDockMac) {
    new_mac_address =
        ReadMacAddressFromFile(base::FilePath(kVpdDockMacFilePath));
  } else if (source == kUsbEthernetMacAddressSourceBuiltinAdapterMac) {
    new_mac_address =
        ReadMacAddressFromFile(base::FilePath(kVpdEthernetMacFilePath));
  } else if (source == kUsbEthernetMacAddressSourceUsbAdapterMac) {
    new_mac_address = permanent_mac_address_;
  } else {
    Error::PopulateAndLog(FROM_HERE, error, Error::kInvalidArguments,
                          "Unknown source: " + source);
    return;
  }

  if (new_mac_address.empty()) {
    Error::PopulateAndLog(
        FROM_HERE, error, Error::kNotSupported,
        "Failed to find out new MAC address for source: " + source);
    return;
  }

  if (new_mac_address == mac_address()) {
    SLOG(this, 4) << __func__ << " new MAC address is equal to the old one";
    if (usb_ethernet_mac_address_source_ != source) {
      usb_ethernet_mac_address_source_ = source;
      adaptor()->EmitStringChanged(kUsbEthernetMacAddressSourceProperty,
                                   usb_ethernet_mac_address_source_);
    }
    if (error) {
      error->Populate(Error::kSuccess);
    }
    return;
  }

  SLOG(this, 2) << "Send netlink request to change MAC address for "
                << link_name() << " device from " << mac_address() << " to "
                << new_mac_address;

  rtnl_handler()->SetInterfaceMac(
      interface_index(), ByteString::CreateFromHexString(new_mac_address),
      base::BindOnce(&Ethernet::OnSetInterfaceMacResponse,
                     weak_ptr_factory_.GetWeakPtr(), source, new_mac_address,
                     callback));
}

std::string Ethernet::ReadMacAddressFromFile(const base::FilePath& file_path) {
  std::string mac_address;
  if (!base::ReadFileToString(file_path, &mac_address)) {
    PLOG(ERROR) << "Unable to read MAC address from file: "
                << file_path.value();
    return std::string();
  }
  base::RemoveChars(base::ToLowerASCII(mac_address), ":", &mac_address);
  if (!IsValidMac(mac_address)) {
    LOG(ERROR) << "MAC address from file " << file_path.value()
               << " is invalid: " << mac_address;
    return std::string();
  }
  return mac_address;
}

void Ethernet::OnSetInterfaceMacResponse(const std::string& mac_address_source,
                                         const std::string& new_mac_address,
                                         const ResultCallback& callback,
                                         int32_t error) {
  if (error) {
    LOG(ERROR) << __func__ << " received response with error "
               << strerror(error);
    if (!callback.is_null()) {
      callback.Run(Error(Error::kNotSupported));
    }
    return;
  }

  SLOG(this, 2) << __func__ << " received successful response";

  usb_ethernet_mac_address_source_ = mac_address_source;
  adaptor()->EmitStringChanged(kUsbEthernetMacAddressSourceProperty,
                               usb_ethernet_mac_address_source_);

  set_mac_address(new_mac_address);
  if (!callback.is_null()) {
    callback.Run(Error(Error::kSuccess));
  }
}

void Ethernet::set_mac_address(const std::string& new_mac_address) {
  SLOG(this, 2) << __func__ << " " << new_mac_address;

  ProfileRefPtr profile;
  if (service_) {
    profile = service_->profile();
  }
  // Abandon and adopt service if service storage identifier will change after
  // changing ethernet MAC address.
  if (permanent_mac_address_.empty() && profile &&
      !service_->HasStorageIdentifier()) {
    profile->AbandonService(service_);
    Device::set_mac_address(new_mac_address);
    profile->AdoptService(service_);
  } else {
    Device::set_mac_address(new_mac_address);
  }

  if (service_) {
    DisconnectFrom(service_.get());
    ConnectTo(service_.get());
  }
}

std::string Ethernet::GetPermanentMacAddressFromKernel() {
  struct ifreq ifr;
  if (link_name().length() >= sizeof(ifr.ifr_name)) {
    LOG(WARNING) << "Interface name " << link_name()
                 << " too long: " << link_name().size()
                 << " >= " << sizeof(ifr.ifr_name);
    return std::string();
  }

  memset(&ifr, 0, sizeof(ifr));
  memcpy(ifr.ifr_name, link_name().data(), link_name().length());

  constexpr int kPermAddrBufferSize =
      sizeof(struct ethtool_perm_addr) + MAX_ADDR_LEN;
  char perm_addr_buffer[kPermAddrBufferSize];
  memset(perm_addr_buffer, 0, kPermAddrBufferSize);
  struct ethtool_perm_addr* perm_addr = static_cast<struct ethtool_perm_addr*>(
      static_cast<void*>(perm_addr_buffer));
  perm_addr->cmd = ETHTOOL_GPERMADDR;
  perm_addr->size = MAX_ADDR_LEN;

  ifr.ifr_data = perm_addr;

  const int fd = sockets_->Socket(PF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
  if (fd < 0) {
    PLOG(WARNING) << "Failed to allocate socket";
    return std::string();
  }

  ScopedSocketCloser socket_closer(sockets_.get(), fd);
  int err = sockets_->Ioctl(fd, SIOCETHTOOL, &ifr);
  if (err < 0) {
    PLOG(WARNING) << "Failed to read permanent MAC address";
    return std::string();
  }

  if (perm_addr->size != ETH_ALEN) {
    LOG(WARNING) << "Invalid permanent MAC address size: " << perm_addr->size;
    return std::string();
  }

  std::string mac_address =
      base::ToLowerASCII(ByteString(perm_addr->data, ETH_ALEN).HexEncode());
  if (!IsValidMac(mac_address)) {
    LOG(ERROR) << "Invalid permanent MAC address: " << mac_address;
    return std::string();
  }
  return mac_address;
}

std::string Ethernet::GetDeviceBusType() const {
  auto device_id = DeviceId::CreateFromSysfs(base::FilePath(
      base::StringPrintf("/sys/class/net/%s/device", link_name().c_str())));

  constexpr DeviceId kPciDevicePattern{DeviceId::BusType::kPci};
  if (device_id && device_id->Match(kPciDevicePattern)) {
    return kDeviceBusTypePci;
  }
  constexpr DeviceId kUsbDevicePattern{DeviceId::BusType::kUsb};
  if (device_id && device_id->Match(kUsbDevicePattern)) {
    return kDeviceBusTypeUsb;
  }
  return std::string();
}

}  // namespace shill