Scrubbed part of the code.

[mirror_edk2.git] / MdeModulePkg / Universal / Network / Dhcp4Dxe / Dhcp4Driver.c

/** @file\r
\r
Copyright (c) 2006 - 2008, Intel Corporation\r
All rights reserved. This program and the accompanying materials\r
are licensed and made available under the terms and conditions of the BSD License\r
which accompanies this distribution.  The full text of the license may be found at\r
http://opensource.org/licenses/bsd-license.php\r
\r
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
\r
\r
Module Name:\r
\r
  Dhcp4Driver.c\r
\r
Abstract:\r
\r
\r
**/\r
\r
#include "Dhcp4Impl.h"\r
#include "Dhcp4Driver.h"\r
\r
EFI_DRIVER_BINDING_PROTOCOL gDhcp4DriverBinding = {\r
  Dhcp4DriverBindingSupported,\r
  Dhcp4DriverBindingStart,\r
  Dhcp4DriverBindingStop,\r
  0xa,\r
  NULL,\r
  NULL\r
};\r
\r
EFI_SERVICE_BINDING_PROTOCOL mDhcp4ServiceBindingTemplate = {\r
  Dhcp4ServiceBindingCreateChild,\r
  Dhcp4ServiceBindingDestroyChild\r
};\r
\r
/**\r
  This is the declaration of an EFI image entry point. This entry point is\r
  the same for UEFI Applications, UEFI OS Loaders, and UEFI Drivers including\r
  both device drivers and bus drivers.\r
  \r
  Entry point of the DHCP driver to install various protocols.\r
\r
  @param  ImageHandle           The firmware allocated handle for the UEFI image.\r
  @param  SystemTable           A pointer to the EFI System Table.\r
\r
  @retval EFI_SUCCESS           The operation completed successfully.\r
  @retval EFI_OUT_OF_RESOURCES  The request could not be completed due to a lack of resources.\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
Dhcp4DriverEntryPoint (\r
  IN EFI_HANDLE             ImageHandle,\r
  IN EFI_SYSTEM_TABLE       *SystemTable\r
  )\r
{\r
  return EfiLibInstallDriverBindingComponentName2 (\r
           ImageHandle,\r
           SystemTable,\r
           &gDhcp4DriverBinding,\r
           ImageHandle,\r
           &gDhcp4ComponentName,\r
           &gDhcp4ComponentName2\r
           );\r
}\r
\r
\r
/**\r
  Test to see if this driver supports ControllerHandle. This service\r
  is called by the EFI boot service ConnectController(). In\r
  order to make drivers as small as possible, there are a few calling\r
  restrictions for this service. ConnectController() must\r
  follow these calling restrictions. If any other agent wishes to call\r
  Supported() it must also follow these calling restrictions.\r
\r
  @param  This                Protocol instance pointer.\r
  @param  ControllerHandle    Handle of device to test\r
  @param  RemainingDevicePath Optional parameter use to pick a specific child\r
                              device to start.\r
\r
  @retval EFI_SUCCESS         This driver supports this device\r
  @retval EFI_ALREADY_STARTED This driver is already running on this device\r
  @retval other               This driver does not support this device\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
Dhcp4DriverBindingSupported (\r
  IN EFI_DRIVER_BINDING_PROTOCOL  *This,\r
  IN EFI_HANDLE                   ControllerHandle,\r
  IN EFI_DEVICE_PATH_PROTOCOL     *RemainingDevicePath OPTIONAL\r
  )\r
{\r
  EFI_STATUS  Status;\r
\r
  Status = gBS->OpenProtocol (\r
                  ControllerHandle,\r
                  &gEfiUdp4ServiceBindingProtocolGuid,\r
                  NULL,\r
                  This->DriverBindingHandle,\r
                  ControllerHandle,\r
                  EFI_OPEN_PROTOCOL_TEST_PROTOCOL\r
                  );\r
\r
  return Status;\r
}\r
\r
\r
\r
/**\r
  Configure the default UDP child to receive all the DHCP traffics\r
  on this network interface.\r
\r
  @param  UdpIo                  The UDP IO port to configure\r
  @param  Context                The context to the function\r
\r
  @retval EFI_SUCCESS            The UDP IO port is successfully configured.\r
  @retval Others                 Failed to configure the UDP child.\r
\r
**/\r
EFI_STATUS\r
DhcpConfigUdpIo (\r
  IN UDP_IO_PORT            *UdpIo,\r
  IN VOID                   *Context\r
  )\r
{\r
  EFI_UDP4_CONFIG_DATA      UdpConfigData;\r
\r
  UdpConfigData.AcceptBroadcast           = TRUE;\r
  UdpConfigData.AcceptPromiscuous         = FALSE;\r
  UdpConfigData.AcceptAnyPort             = FALSE;\r
  UdpConfigData.AllowDuplicatePort        = TRUE;\r
  UdpConfigData.TypeOfService             = 0;\r
  UdpConfigData.TimeToLive                = 64;\r
  UdpConfigData.DoNotFragment             = FALSE;\r
  UdpConfigData.ReceiveTimeout            = 0;\r
  UdpConfigData.TransmitTimeout           = 0;\r
\r
  UdpConfigData.UseDefaultAddress         = FALSE;\r
  UdpConfigData.StationPort               = DHCP_CLIENT_PORT;\r
  UdpConfigData.RemotePort                = DHCP_SERVER_PORT;\r
\r
  ZeroMem (&UdpConfigData.StationAddress, sizeof (EFI_IPv4_ADDRESS));\r
  ZeroMem (&UdpConfigData.SubnetMask, sizeof (EFI_IPv4_ADDRESS));\r
  ZeroMem (&UdpConfigData.RemoteAddress, sizeof (EFI_IPv4_ADDRESS));\r
\r
  return UdpIo->Udp->Configure (UdpIo->Udp, &UdpConfigData);;\r
}\r
\r
\r
\r
/**\r
  Destory the DHCP service. The Dhcp4 service may be partly initialized,\r
  or partly destroyed. If a resource is destroyed, it is marked as so in\r
  case the destroy failed and being called again later.\r
\r
  @param  DhcpSb                 The DHCP service instance to destory.\r
\r
  @retval EFI_SUCCESS            Always return success.\r
\r
**/\r
EFI_STATUS\r
Dhcp4CloseService (\r
  IN DHCP_SERVICE           *DhcpSb\r
  )\r
{\r
  DhcpCleanLease (DhcpSb);\r
\r
  if (DhcpSb->UdpIo != NULL) {\r
    UdpIoFreePort (DhcpSb->UdpIo);\r
    DhcpSb->UdpIo = NULL;\r
  }\r
\r
  if (DhcpSb->Timer != NULL) {\r
    gBS->SetTimer (DhcpSb->Timer, TimerCancel, 0);\r
    gBS->CloseEvent (DhcpSb->Timer);\r
\r
    DhcpSb->Timer = NULL;\r
  }\r
\r
  return EFI_SUCCESS;\r
}\r
\r
\r
\r
/**\r
  Create a new DHCP service binding instance for the controller.\r
\r
  @param  Controller             The controller to install DHCP service binding\r
                                 protocol onto\r
  @param  ImageHandle            The driver's image handle\r
  @param  Service                The variable to receive the created DHCP service\r
                                 instance.\r
\r
  @retval EFI_OUT_OF_RESOURCES   Failed to allocate resource .\r
  @retval EFI_SUCCESS            The DHCP service instance is created.\r
  @retval other                  Other error occurs.\r
\r
**/\r
EFI_STATUS\r
Dhcp4CreateService (\r
  IN  EFI_HANDLE            Controller,\r
  IN  EFI_HANDLE            ImageHandle,\r
  OUT DHCP_SERVICE          **Service\r
  )\r
{\r
  DHCP_SERVICE              *DhcpSb;\r
  EFI_STATUS                Status;\r
\r
  *Service  = NULL;\r
  DhcpSb    = AllocateZeroPool (sizeof (DHCP_SERVICE));\r
\r
  if (DhcpSb == NULL) {\r
    return EFI_OUT_OF_RESOURCES;\r
  }\r
\r
  DhcpSb->Signature       = DHCP_SERVICE_SIGNATURE;\r
  DhcpSb->ServiceState    = DHCP_UNCONFIGED;\r
  DhcpSb->InDestory       = FALSE;\r
  DhcpSb->Controller      = Controller;\r
  DhcpSb->Image           = ImageHandle;\r
  InitializeListHead (&DhcpSb->Children);\r
  DhcpSb->DhcpState       = Dhcp4Stopped;\r
  DhcpSb->Xid             = NET_RANDOM (NetRandomInitSeed ());\r
  CopyMem (\r
    &DhcpSb->ServiceBinding,\r
    &mDhcp4ServiceBindingTemplate,\r
    sizeof (EFI_SERVICE_BINDING_PROTOCOL)\r
    );\r
  //\r
  // Create various resources, UdpIo, Timer, and get Mac address\r
  //\r
  Status = gBS->CreateEvent (\r
                  EVT_NOTIFY_SIGNAL | EVT_TIMER,\r
                  TPL_CALLBACK,\r
                  DhcpOnTimerTick,\r
                  DhcpSb,\r
                  &DhcpSb->Timer\r
                  );\r
\r
  if (EFI_ERROR (Status)) {\r
    goto ON_ERROR;\r
  }\r
\r
  DhcpSb->UdpIo = UdpIoCreatePort (Controller, ImageHandle, DhcpConfigUdpIo, NULL);\r
\r
  if (DhcpSb->UdpIo == NULL) {\r
    Status = EFI_OUT_OF_RESOURCES;\r
    goto ON_ERROR;\r
  }\r
\r
  DhcpSb->HwLen  = (UINT8) DhcpSb->UdpIo->SnpMode.HwAddressSize;\r
  DhcpSb->HwType = DhcpSb->UdpIo->SnpMode.IfType;\r
  CopyMem (&DhcpSb->Mac, &DhcpSb->UdpIo->SnpMode.CurrentAddress, sizeof (DhcpSb->Mac));\r
\r
  *Service       = DhcpSb;\r
  return EFI_SUCCESS;\r
\r
ON_ERROR:\r
  Dhcp4CloseService (DhcpSb);\r
  gBS->FreePool (DhcpSb);\r
\r
  return Status;\r
}\r
\r
\r
/**\r
  Start this driver on ControllerHandle. This service is called by the\r
  EFI boot service ConnectController(). In order to make\r
  drivers as small as possible, there are a few calling restrictions for\r
  this service. ConnectController() must follow these\r
  calling restrictions. If any other agent wishes to call Start() it\r
  must also follow these calling restrictions.\r
\r
  @param  This                 Protocol instance pointer.\r
  @param  ControllerHandle     Handle of device to bind driver to\r
  @param  RemainingDevicePath  Optional parameter use to pick a specific child\r
                               device to start.\r
\r
  @retval EFI_SUCCESS          This driver is added to ControllerHandle\r
  @retval EFI_ALREADY_STARTED  This driver is already running on ControllerHandle\r
  @retval other                This driver does not support this device\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
Dhcp4DriverBindingStart (\r
  IN EFI_DRIVER_BINDING_PROTOCOL  *This,\r
  IN EFI_HANDLE                   ControllerHandle,\r
  IN EFI_DEVICE_PATH_PROTOCOL     *RemainingDevicePath OPTIONAL\r
  )\r
{\r
  DHCP_SERVICE              *DhcpSb;\r
  EFI_STATUS                Status;\r
\r
  //\r
  // First: test for the DHCP4 Protocol\r
  //\r
  Status = gBS->OpenProtocol (\r
                  ControllerHandle,\r
                  &gEfiDhcp4ServiceBindingProtocolGuid,\r
                  NULL,\r
                  This->DriverBindingHandle,\r
                  ControllerHandle,\r
                  EFI_OPEN_PROTOCOL_TEST_PROTOCOL\r
                  );\r
\r
  if (Status == EFI_SUCCESS) {\r
    return EFI_ALREADY_STARTED;\r
  }\r
\r
  Status = Dhcp4CreateService (ControllerHandle, This->DriverBindingHandle, &DhcpSb);\r
\r
  if (EFI_ERROR (Status)) {\r
    return Status;\r
  }\r
\r
  Status = gBS->SetTimer (DhcpSb->Timer, TimerPeriodic, TICKS_PER_SECOND);\r
\r
  if (EFI_ERROR (Status)) {\r
    goto ON_ERROR;\r
  }\r
\r
  //\r
  // Install the Dhcp4ServiceBinding Protocol onto ControlerHandle\r
  //\r
  Status = gBS->InstallMultipleProtocolInterfaces (\r
                  &ControllerHandle,\r
                  &gEfiDhcp4ServiceBindingProtocolGuid,\r
                  &DhcpSb->ServiceBinding,\r
                  NULL\r
                  );\r
\r
  if (EFI_ERROR (Status)) {\r
    goto ON_ERROR;\r
  }\r
\r
  return Status;\r
\r
ON_ERROR:\r
  Dhcp4CloseService (DhcpSb);\r
  gBS->FreePool (DhcpSb);\r
  return Status;\r
}\r
\r
\r
/**\r
  Stop this driver on ControllerHandle. This service is called by the\r
  EFI boot service DisconnectController(). In order to\r
  make drivers as small as possible, there are a few calling\r
  restrictions for this service. DisconnectController()\r
  must follow these calling restrictions. If any other agent wishes\r
  to call Stop() it must also follow these calling restrictions.\r
  \r
  @param  This              Protocol instance pointer.\r
  @param  ControllerHandle  Handle of device to stop driver on\r
  @param  NumberOfChildren  Number of Handles in ChildHandleBuffer. If number of\r
                            children is zero stop the entire bus driver.\r
  @param  ChildHandleBuffer List of Child Handles to Stop.\r
\r
  @retval EFI_SUCCESS       This driver is removed ControllerHandle\r
  @retval other             This driver was not removed from this device\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
Dhcp4DriverBindingStop (\r
  IN  EFI_DRIVER_BINDING_PROTOCOL  *This,\r
  IN  EFI_HANDLE                   ControllerHandle,\r
  IN  UINTN                        NumberOfChildren,\r
  IN  EFI_HANDLE                   *ChildHandleBuffer\r
  )\r
{\r
  EFI_SERVICE_BINDING_PROTOCOL  *ServiceBinding;\r
  DHCP_SERVICE                  *DhcpSb;\r
  DHCP_PROTOCOL                 *Instance;\r
  EFI_HANDLE                    NicHandle;\r
  EFI_STATUS                    Status;\r
  EFI_TPL                       OldTpl;\r
\r
  //\r
  // DHCP driver opens UDP child, So, the ControllerHandle is the\r
  // UDP child handle. locate the Nic handle first.\r
  //\r
  NicHandle = NetLibGetNicHandle (ControllerHandle, &gEfiUdp4ProtocolGuid);\r
\r
  if (NicHandle == NULL) {\r
    return EFI_DEVICE_ERROR;\r
  }\r
\r
   Status = gBS->OpenProtocol (\r
                  NicHandle,\r
                  &gEfiDhcp4ServiceBindingProtocolGuid,\r
                  (VOID **) &ServiceBinding,\r
                  This->DriverBindingHandle,\r
                  NicHandle,\r
                  EFI_OPEN_PROTOCOL_GET_PROTOCOL\r
                  );\r
\r
  if (EFI_ERROR (Status)) {\r
    return EFI_DEVICE_ERROR;\r
  }\r
\r
  DhcpSb = DHCP_SERVICE_FROM_THIS (ServiceBinding);\r
\r
  if (DhcpSb->InDestory) {\r
    return EFI_SUCCESS;\r
  }\r
\r
  OldTpl = gBS->RaiseTPL (TPL_CALLBACK);\r
\r
  if (NumberOfChildren == 0) {\r
\r
    DhcpSb->InDestory    = TRUE;\r
    DhcpSb->ServiceState = DHCP_DESTORY;\r
\r
    gBS->UninstallProtocolInterface (\r
           NicHandle,\r
           &gEfiDhcp4ServiceBindingProtocolGuid,\r
           ServiceBinding\r
           );\r
\r
    Dhcp4CloseService (DhcpSb);\r
\r
    gBS->FreePool (DhcpSb);\r
  } else {\r
    //\r
    // Don't use NET_LIST_FOR_EACH_SAFE here, Dhcp4ServiceBindingDestoryChild\r
    // may cause other child to be deleted.\r
    //\r
    while (!IsListEmpty (&DhcpSb->Children)) {\r
      Instance = NET_LIST_HEAD (&DhcpSb->Children, DHCP_PROTOCOL, Link);\r
      ServiceBinding->DestroyChild (ServiceBinding, Instance->Handle);\r
    }\r
\r
    if (DhcpSb->NumChildren != 0) {\r
      Status = EFI_DEVICE_ERROR;\r
    }\r
  }\r
\r
  gBS->RestoreTPL (OldTpl);\r
\r
  return Status;\r
}\r
\r
\r
/**\r
  Initialize a new DHCP instance.\r
\r
  @param  DhcpSb                 The dhcp service instance\r
  @param  Instance               The dhcp instance to initialize\r
\r
  @return None\r
\r
**/\r
VOID\r
DhcpInitProtocol (\r
  IN     DHCP_SERVICE           *DhcpSb,\r
  IN OUT DHCP_PROTOCOL          *Instance\r
  )\r
{\r
  Instance->Signature         = DHCP_PROTOCOL_SIGNATURE;\r
  CopyMem (&Instance->Dhcp4Protocol, &mDhcp4ProtocolTemplate, sizeof (Instance->Dhcp4Protocol));\r
  InitializeListHead (&Instance->Link);\r
  Instance->Handle            = NULL;\r
  Instance->Service           = DhcpSb;\r
  Instance->InDestory         = FALSE;\r
  Instance->CompletionEvent   = NULL;\r
  Instance->RenewRebindEvent  = NULL;\r
  Instance->Token             = NULL;\r
  Instance->UdpIo             = NULL;\r
  NetbufQueInit (&Instance->ResponseQueue);\r
}\r
\r
\r
/**\r
  Creates a child handle with a set of I/O services.\r
\r
  @param  This        Protocol instance pointer.\r
  @param  ChildHandle Pointer to the handle of the child to create.  If it is NULL,\r
                      then a new handle is created.  If it is not NULL, then the\r
                      I/O services are added to the existing child handle.\r
\r
  @retval EFI_SUCCES            The child handle was created with the I/O services\r
  @retval EFI_INVALID_PARAMETER ChildHandle is NULL.\r
  @retval EFI_OUT_OF_RESOURCES  There are not enough resources availabe to create\r
                                the child\r
  @retval other                 The child handle was not created\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
Dhcp4ServiceBindingCreateChild (\r
  IN EFI_SERVICE_BINDING_PROTOCOL  *This,\r
  IN EFI_HANDLE                    *ChildHandle\r
  )\r
{\r
  DHCP_SERVICE              *DhcpSb;\r
  DHCP_PROTOCOL             *Instance;\r
  EFI_STATUS                Status;\r
  EFI_TPL                   OldTpl;\r
  VOID                      *Udp4;\r
\r
  if ((This == NULL) || (ChildHandle == NULL)) {\r
    return EFI_INVALID_PARAMETER;\r
  }\r
\r
  Instance = AllocatePool (sizeof (*Instance));\r
\r
  if (Instance == NULL) {\r
    return EFI_OUT_OF_RESOURCES;\r
  }\r
\r
  DhcpSb = DHCP_SERVICE_FROM_THIS (This);\r
  DhcpInitProtocol (DhcpSb, Instance);\r
\r
  //\r
  // Install DHCP4 onto ChildHandle\r
  //\r
  Status = gBS->InstallMultipleProtocolInterfaces (\r
                  ChildHandle,\r
                  &gEfiDhcp4ProtocolGuid,\r
                  &Instance->Dhcp4Protocol,\r
                  NULL\r
                  );\r
\r
  if (EFI_ERROR (Status)) {\r
    gBS->FreePool (Instance);\r
    return Status;\r
  }\r
\r
  Instance->Handle  = *ChildHandle;\r
\r
  //\r
  // Open the Udp4 protocol BY_CHILD.\r
  //\r
  Status = gBS->OpenProtocol (\r
                  DhcpSb->UdpIo->UdpHandle,\r
                  &gEfiUdp4ProtocolGuid,\r
                  (VOID **) &Udp4,\r
                  gDhcp4DriverBinding.DriverBindingHandle,\r
                  Instance->Handle,\r
                  EFI_OPEN_PROTOCOL_BY_CHILD_CONTROLLER\r
                  );\r
  if (EFI_ERROR (Status)) {\r
    gBS->UninstallMultipleProtocolInterfaces (\r
           Instance->Handle,\r
           &gEfiDhcp4ProtocolGuid,\r
           &Instance->Dhcp4Protocol,\r
           NULL\r
           );\r
\r
    gBS->FreePool (Instance);\r
    return Status;\r
  }\r
\r
  OldTpl = gBS->RaiseTPL (TPL_CALLBACK);\r
\r
  InsertTailList (&DhcpSb->Children, &Instance->Link);\r
  DhcpSb->NumChildren++;\r
\r
  gBS->RestoreTPL (OldTpl);\r
\r
  return EFI_SUCCESS;\r
}\r
\r
\r
/**\r
  Destroys a child handle with a set of I/O services.\r
\r
  @param  This        Protocol instance pointer.\r
  @param  ChildHandle Handle of the child to destroy\r
\r
  @retval EFI_SUCCES            The I/O services were removed from the child handle\r
  @retval EFI_UNSUPPORTED       The child handle does not support the I/O services\r
                                that are being removed.\r
  @retval EFI_INVALID_PARAMETER Child handle is not a valid EFI Handle.\r
  @retval EFI_ACCESS_DENIED     The child handle could not be destroyed because its\r
                                I/O services are being used.\r
  @retval other                 The child handle was not destroyed\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
Dhcp4ServiceBindingDestroyChild (\r
  IN EFI_SERVICE_BINDING_PROTOCOL  *This,\r
  IN EFI_HANDLE                    ChildHandle\r
  )\r
{\r
  DHCP_SERVICE              *DhcpSb;\r
  DHCP_PROTOCOL             *Instance;\r
  EFI_DHCP4_PROTOCOL        *Dhcp;\r
  EFI_TPL                   OldTpl;\r
  EFI_STATUS                Status;\r
\r
  if ((This == NULL) || (ChildHandle == NULL)) {\r
    return EFI_INVALID_PARAMETER;\r
  }\r
\r
  //\r
  // Retrieve the private context data structures\r
  //\r
  Status = gBS->OpenProtocol (\r
                  ChildHandle,\r
                  &gEfiDhcp4ProtocolGuid,\r
                  (VOID **) &Dhcp,\r
                  gDhcp4DriverBinding.DriverBindingHandle,\r
                  ChildHandle,\r
                  EFI_OPEN_PROTOCOL_GET_PROTOCOL\r
                  );\r
\r
  if (EFI_ERROR (Status)) {\r
    return EFI_UNSUPPORTED;\r
  }\r
\r
  Instance  = DHCP_INSTANCE_FROM_THIS (Dhcp);\r
  DhcpSb    = DHCP_SERVICE_FROM_THIS (This);\r
\r
  if (Instance->Service != DhcpSb) {\r
    return EFI_INVALID_PARAMETER;\r
  }\r
\r
  //\r
  // A child can be destroyed more than once. For example,\r
  // Dhcp4DriverBindingStop will destroy all of its children.\r
  // when caller driver is being stopped, it will destory the\r
  // dhcp child it opens.\r
  //\r
  if (Instance->InDestory) {\r
    return EFI_SUCCESS;\r
  }\r
\r
  OldTpl = gBS->RaiseTPL (TPL_CALLBACK);\r
  Instance->InDestory = TRUE;\r
\r
  //\r
  // Close the Udp4 protocol.\r
  //\r
  gBS->CloseProtocol (\r
         DhcpSb->UdpIo->UdpHandle,\r
         &gEfiUdp4ProtocolGuid,\r
         gDhcp4DriverBinding.DriverBindingHandle,\r
         ChildHandle\r
         );\r
\r
  //\r
  // Uninstall the DHCP4 protocol first to enable a top down destruction.\r
  //\r
  Status = gBS->UninstallProtocolInterface (\r
                  ChildHandle,\r
                  &gEfiDhcp4ProtocolGuid,\r
                  Dhcp\r
                  );\r
\r
  if (EFI_ERROR (Status)) {\r
    Instance->InDestory = FALSE;\r
\r
    gBS->RestoreTPL (OldTpl);\r
    return Status;\r
  }\r
\r
  if (DhcpSb->ActiveChild == Instance) {\r
    DhcpYieldControl (DhcpSb);\r
  }\r
\r
  RemoveEntryList (&Instance->Link);\r
  DhcpSb->NumChildren--;\r
\r
  gBS->RestoreTPL (OldTpl);\r
\r
  gBS->FreePool (Instance);\r
  return EFI_SUCCESS;\r
}\r