[mirror_edk2.git] / NetworkPkg / DnsDxe / DnsDhcp.c

/** @file\r
Functions implementation related with DHCPv4/v6 for DNS driver.\r
\r
Copyright (c) 2015 - 2018, Intel Corporation. All rights reserved.<BR>\r
SPDX-License-Identifier: BSD-2-Clause-Patent\r
\r
**/\r
\r
#include "DnsImpl.h"\r
\r
/**\r
  This function initialize the DHCP4 message instance.\r
\r
  This function will pad each item of dhcp4 message packet.\r
\r
  @param  Seed             Pointer to the message instance of the DHCP4 packet.\r
  @param  InterfaceInfo    Pointer to the EFI_IP4_CONFIG2_INTERFACE_INFO instance.\r
\r
**/\r
VOID\r
DnsInitSeedPacket (\r
  OUT EFI_DHCP4_PACKET                *Seed,\r
  IN  EFI_IP4_CONFIG2_INTERFACE_INFO  *InterfaceInfo\r
  )\r
{\r
  EFI_DHCP4_HEADER  *Header;\r
\r
  //\r
  // Get IfType and HwAddressSize from SNP mode data.\r
  //\r
  Seed->Size   = sizeof (EFI_DHCP4_PACKET);\r
  Seed->Length = sizeof (Seed->Dhcp4);\r
  Header       = &Seed->Dhcp4.Header;\r
  ZeroMem (Header, sizeof (EFI_DHCP4_HEADER));\r
  Header->OpCode    = DHCP4_OPCODE_REQUEST;\r
  Header->HwType    = InterfaceInfo->IfType;\r
  Header->HwAddrLen = (UINT8)InterfaceInfo->HwAddressSize;\r
  CopyMem (Header->ClientHwAddr, &(InterfaceInfo->HwAddress), Header->HwAddrLen);\r
\r
  Seed->Dhcp4.Magik     = DHCP4_MAGIC;\r
  Seed->Dhcp4.Option[0] = DHCP4_TAG_EOP;\r
}\r
\r
/**\r
  The common notify function.\r
\r
  @param[in]  Event   The event signaled.\r
  @param[in]  Context The context.\r
\r
**/\r
VOID\r
EFIAPI\r
DhcpCommonNotify (\r
  IN EFI_EVENT  Event,\r
  IN VOID       *Context\r
  )\r
{\r
  if ((Event == NULL) || (Context == NULL)) {\r
    return;\r
  }\r
\r
  *((BOOLEAN *)Context) = TRUE;\r
}\r
\r
/**\r
  Parse the ACK to get required information\r
\r
  @param  Dhcp4            The DHCP4 protocol.\r
  @param  Packet           Packet waiting for parse.\r
  @param  DnsServerInfor   The required Dns4 server information.\r
\r
  @retval EFI_SUCCESS           The DNS information is got from the DHCP ACK.\r
  @retval EFI_NO_MAPPING        DHCP failed to acquire address and other information.\r
  @retval EFI_DEVICE_ERROR      Other errors as indicated.\r
  @retval EFI_OUT_OF_RESOURCES  Failed to allocate memory.\r
\r
**/\r
EFI_STATUS\r
ParseDhcp4Ack (\r
  IN EFI_DHCP4_PROTOCOL  *Dhcp4,\r
  IN EFI_DHCP4_PACKET    *Packet,\r
  IN DNS4_SERVER_INFOR   *DnsServerInfor\r
  )\r
{\r
  EFI_STATUS               Status;\r
  UINT32                   OptionCount;\r
  EFI_DHCP4_PACKET_OPTION  **OptionList;\r
  UINT32                   ServerCount;\r
  EFI_IPv4_ADDRESS         *ServerList;\r
  UINT32                   Index;\r
  UINT32                   Count;\r
\r
  ServerCount = 0;\r
  ServerList  = NULL;\r
\r
  OptionCount = 0;\r
  OptionList  = NULL;\r
\r
  Status = Dhcp4->Parse (Dhcp4, Packet, &OptionCount, OptionList);\r
  if (Status != EFI_BUFFER_TOO_SMALL) {\r
    return EFI_DEVICE_ERROR;\r
  }\r
\r
  OptionList = AllocatePool (OptionCount * sizeof (EFI_DHCP4_PACKET_OPTION *));\r
  if (OptionList == NULL) {\r
    return EFI_OUT_OF_RESOURCES;\r
  }\r
\r
  Status = Dhcp4->Parse (Dhcp4, Packet, &OptionCount, OptionList);\r
  if (EFI_ERROR (Status)) {\r
    gBS->FreePool (OptionList);\r
    return EFI_DEVICE_ERROR;\r
  }\r
\r
  Status = EFI_NOT_FOUND;\r
\r
  for (Index = 0; Index < OptionCount; Index++) {\r
    //\r
    // Get DNS server addresses\r
    //\r
    if (OptionList[Index]->OpCode == DHCP4_TAG_DNS_SERVER) {\r
      if (((OptionList[Index]->Length & 0x3) != 0) || (OptionList[Index]->Length == 0)) {\r
        Status = EFI_DEVICE_ERROR;\r
        break;\r
      }\r
\r
      ServerCount = OptionList[Index]->Length/4;\r
      ServerList  = AllocatePool (ServerCount * sizeof (EFI_IPv4_ADDRESS));\r
      if (ServerList == NULL) {\r
        return EFI_OUT_OF_RESOURCES;\r
      }\r
\r
      for (Count = 0; Count < ServerCount; Count++) {\r
        CopyMem (ServerList + Count, &OptionList[Index]->Data[4 * Count], sizeof (EFI_IPv4_ADDRESS));\r
      }\r
\r
      *(DnsServerInfor->ServerCount) = ServerCount;\r
      DnsServerInfor->ServerList     = ServerList;\r
\r
      Status = EFI_SUCCESS;\r
    }\r
  }\r
\r
  gBS->FreePool (OptionList);\r
\r
  return Status;\r
}\r
\r
/**\r
  EFI_DHCP6_INFO_CALLBACK is provided by the consumer of the EFI DHCPv6 Protocol\r
  instance to intercept events that occurs in the DHCPv6 Information Request\r
  exchange process.\r
\r
  @param  This                  Pointer to the EFI_DHCP6_PROTOCOL instance that\r
                                is used to configure this  callback function.\r
  @param  Context               Pointer to the context that is initialized in\r
                                the EFI_DHCP6_PROTOCOL.InfoRequest().\r
  @param  Packet                Pointer to Reply packet that has been received.\r
                                The EFI DHCPv6 Protocol instance is responsible\r
                                for freeing the buffer.\r
\r
  @retval EFI_SUCCESS           The DNS information is got from the DHCP ACK.\r
  @retval EFI_DEVICE_ERROR      Other errors as indicated.\r
  @retval EFI_OUT_OF_RESOURCES  Failed to allocate memory.\r
**/\r
EFI_STATUS\r
EFIAPI\r
ParseDhcp6Ack (\r
  IN EFI_DHCP6_PROTOCOL  *This,\r
  IN VOID                *Context,\r
  IN EFI_DHCP6_PACKET    *Packet\r
  )\r
{\r
  EFI_STATUS               Status;\r
  UINT32                   OptionCount;\r
  EFI_DHCP6_PACKET_OPTION  **OptionList;\r
  DNS6_SERVER_INFOR        *DnsServerInfor;\r
  UINT32                   ServerCount;\r
  EFI_IPv6_ADDRESS         *ServerList;\r
  UINT32                   Index;\r
  UINT32                   Count;\r
\r
  OptionCount = 0;\r
  ServerCount = 0;\r
  ServerList  = NULL;\r
\r
  Status = This->Parse (This, Packet, &OptionCount, NULL);\r
  if (Status != EFI_BUFFER_TOO_SMALL) {\r
    return EFI_DEVICE_ERROR;\r
  }\r
\r
  OptionList = AllocateZeroPool (OptionCount * sizeof (EFI_DHCP6_PACKET_OPTION *));\r
  if (OptionList == NULL) {\r
    return EFI_OUT_OF_RESOURCES;\r
  }\r
\r
  Status = This->Parse (This, Packet, &OptionCount, OptionList);\r
  if (EFI_ERROR (Status)) {\r
    gBS->FreePool (OptionList);\r
    return EFI_DEVICE_ERROR;\r
  }\r
\r
  DnsServerInfor = (DNS6_SERVER_INFOR *)Context;\r
\r
  for (Index = 0; Index < OptionCount; Index++) {\r
    OptionList[Index]->OpCode = NTOHS (OptionList[Index]->OpCode);\r
    OptionList[Index]->OpLen  = NTOHS (OptionList[Index]->OpLen);\r
\r
    //\r
    // Get DNS server addresses from this reply packet.\r
    //\r
    if (OptionList[Index]->OpCode == DHCP6_TAG_DNS_SERVER) {\r
      if (((OptionList[Index]->OpLen & 0xf) != 0) || (OptionList[Index]->OpLen == 0)) {\r
        Status = EFI_DEVICE_ERROR;\r
        gBS->FreePool (OptionList);\r
        return Status;\r
      }\r
\r
      ServerCount = OptionList[Index]->OpLen/16;\r
      ServerList  = AllocatePool (ServerCount * sizeof (EFI_IPv6_ADDRESS));\r
      if (ServerList == NULL) {\r
        gBS->FreePool (OptionList);\r
        return EFI_OUT_OF_RESOURCES;\r
      }\r
\r
      for (Count = 0; Count < ServerCount; Count++) {\r
        CopyMem (ServerList + Count, &OptionList[Index]->Data[16 * Count], sizeof (EFI_IPv6_ADDRESS));\r
      }\r
\r
      *(DnsServerInfor->ServerCount) = ServerCount;\r
      DnsServerInfor->ServerList     = ServerList;\r
    }\r
  }\r
\r
  gBS->FreePool (OptionList);\r
\r
  return Status;\r
}\r
\r
/**\r
  Parse the DHCP ACK to get Dns4 server information.\r
\r
  @param  Instance         The DNS instance.\r
  @param  DnsServerCount   Retrieved Dns4 server Ip count.\r
  @param  DnsServerList    Retrieved Dns4 server Ip list.\r
\r
  @retval EFI_SUCCESS           The Dns4 information is got from the DHCP ACK.\r
  @retval EFI_OUT_OF_RESOURCES  Failed to allocate memory.\r
  @retval EFI_NO_MEDIA          There was a media error.\r
  @retval Others                Other errors as indicated.\r
\r
**/\r
EFI_STATUS\r
GetDns4ServerFromDhcp4 (\r
  IN  DNS_INSTANCE      *Instance,\r
  OUT UINT32            *DnsServerCount,\r
  OUT EFI_IPv4_ADDRESS  **DnsServerList\r
  )\r
{\r
  EFI_STATUS                       Status;\r
  EFI_HANDLE                       Image;\r
  EFI_HANDLE                       Controller;\r
  EFI_STATUS                       MediaStatus;\r
  EFI_HANDLE                       MnpChildHandle;\r
  EFI_MANAGED_NETWORK_PROTOCOL     *Mnp;\r
  EFI_MANAGED_NETWORK_CONFIG_DATA  MnpConfigData;\r
  EFI_HANDLE                       Dhcp4Handle;\r
  EFI_DHCP4_PROTOCOL               *Dhcp4;\r
  EFI_IP4_CONFIG2_PROTOCOL         *Ip4Config2;\r
  UINTN                            DataSize;\r
  VOID                             *Data;\r
  EFI_IP4_CONFIG2_INTERFACE_INFO   *InterfaceInfo;\r
  EFI_DHCP4_PACKET                 SeedPacket;\r
  EFI_DHCP4_PACKET_OPTION          *ParaList[2];\r
  DNS4_SERVER_INFOR                DnsServerInfor;\r
\r
  EFI_DHCP4_TRANSMIT_RECEIVE_TOKEN  Token;\r
  BOOLEAN                           IsDone;\r
  UINTN                             Index;\r
\r
  Image      = Instance->Service->ImageHandle;\r
  Controller = Instance->Service->ControllerHandle;\r
\r
  MnpChildHandle = NULL;\r
  Mnp            = NULL;\r
\r
  Dhcp4Handle = NULL;\r
  Dhcp4       = NULL;\r
\r
  Ip4Config2    = NULL;\r
  DataSize      = 0;\r
  Data          = NULL;\r
  InterfaceInfo = NULL;\r
\r
  ZeroMem ((UINT8 *)ParaList, sizeof (ParaList));\r
\r
  ZeroMem (&MnpConfigData, sizeof (EFI_MANAGED_NETWORK_CONFIG_DATA));\r
\r
  ZeroMem (&DnsServerInfor, sizeof (DNS4_SERVER_INFOR));\r
\r
  ZeroMem (&Token, sizeof (EFI_DHCP4_TRANSMIT_RECEIVE_TOKEN));\r
\r
  DnsServerInfor.ServerCount = DnsServerCount;\r
\r
  IsDone = FALSE;\r
\r
  //\r
  // Check media.\r
  //\r
  MediaStatus = EFI_SUCCESS;\r
  NetLibDetectMediaWaitTimeout (Controller, DNS_CHECK_MEDIA_GET_DHCP_WAITING_TIME, &MediaStatus);\r
  if (MediaStatus != EFI_SUCCESS) {\r
    return EFI_NO_MEDIA;\r
  }\r
\r
  //\r
  // Create a Mnp child instance, get the protocol and config for it.\r
  //\r
  Status = NetLibCreateServiceChild (\r
             Controller,\r
             Image,\r
             &gEfiManagedNetworkServiceBindingProtocolGuid,\r
             &MnpChildHandle\r
             );\r
  if (EFI_ERROR (Status)) {\r
    return Status;\r
  }\r
\r
  Status = gBS->OpenProtocol (\r
                  MnpChildHandle,\r
                  &gEfiManagedNetworkProtocolGuid,\r
                  (VOID **)&Mnp,\r
                  Image,\r
                  Controller,\r
                  EFI_OPEN_PROTOCOL_BY_DRIVER\r
                  );\r
  if (EFI_ERROR (Status)) {\r
    goto ON_EXIT;\r
  }\r
\r
  MnpConfigData.ReceivedQueueTimeoutValue = 0;\r
  MnpConfigData.TransmitQueueTimeoutValue = 0;\r
  MnpConfigData.ProtocolTypeFilter        = IP4_ETHER_PROTO;\r
  MnpConfigData.EnableUnicastReceive      = TRUE;\r
  MnpConfigData.EnableMulticastReceive    = TRUE;\r
  MnpConfigData.EnableBroadcastReceive    = TRUE;\r
  MnpConfigData.EnablePromiscuousReceive  = FALSE;\r
  MnpConfigData.FlushQueuesOnReset        = TRUE;\r
  MnpConfigData.EnableReceiveTimestamps   = FALSE;\r
  MnpConfigData.DisableBackgroundPolling  = FALSE;\r
\r
  Status = Mnp->Configure (Mnp, &MnpConfigData);\r
  if (EFI_ERROR (Status)) {\r
    goto ON_EXIT;\r
  }\r
\r
  //\r
  // Create a DHCP4 child instance and get the protocol.\r
  //\r
  Status = NetLibCreateServiceChild (\r
             Controller,\r
             Image,\r
             &gEfiDhcp4ServiceBindingProtocolGuid,\r
             &Dhcp4Handle\r
             );\r
  if (EFI_ERROR (Status)) {\r
    goto ON_EXIT;\r
  }\r
\r
  Status = gBS->OpenProtocol (\r
                  Dhcp4Handle,\r
                  &gEfiDhcp4ProtocolGuid,\r
                  (VOID **)&Dhcp4,\r
                  Image,\r
                  Controller,\r
                  EFI_OPEN_PROTOCOL_BY_DRIVER\r
                  );\r
  if (EFI_ERROR (Status)) {\r
    goto ON_EXIT;\r
  }\r
\r
  //\r
  // Get Ip4Config2 instance info.\r
  //\r
  Status = gBS->HandleProtocol (Controller, &gEfiIp4Config2ProtocolGuid, (VOID **)&Ip4Config2);\r
  if (EFI_ERROR (Status)) {\r
    goto ON_EXIT;\r
  }\r
\r
  Status = Ip4Config2->GetData (Ip4Config2, Ip4Config2DataTypeInterfaceInfo, &DataSize, Data);\r
  if (EFI_ERROR (Status) && (Status != EFI_BUFFER_TOO_SMALL)) {\r
    goto ON_EXIT;\r
  }\r
\r
  Data = AllocateZeroPool (DataSize);\r
  if (Data == NULL) {\r
    Status = EFI_OUT_OF_RESOURCES;\r
    goto ON_EXIT;\r
  }\r
\r
  Status = Ip4Config2->GetData (Ip4Config2, Ip4Config2DataTypeInterfaceInfo, &DataSize, Data);\r
  if (EFI_ERROR (Status)) {\r
    goto ON_EXIT;\r
  }\r
\r
  InterfaceInfo = (EFI_IP4_CONFIG2_INTERFACE_INFO *)Data;\r
\r
  //\r
  // Build required Token.\r
  //\r
  Status = gBS->CreateEvent (\r
                  EVT_NOTIFY_SIGNAL,\r
                  TPL_NOTIFY,\r
                  DhcpCommonNotify,\r
                  &IsDone,\r
                  &Token.CompletionEvent\r
                  );\r
  if (EFI_ERROR (Status)) {\r
    goto ON_EXIT;\r
  }\r
\r
  SetMem (&Token.RemoteAddress, sizeof (EFI_IPv4_ADDRESS), 0xff);\r
\r
  Token.RemotePort = 67;\r
\r
  Token.ListenPointCount = 1;\r
\r
  Token.ListenPoints = AllocateZeroPool (Token.ListenPointCount * sizeof (EFI_DHCP4_LISTEN_POINT));\r
  if (Token.ListenPoints == NULL) {\r
    Status = EFI_OUT_OF_RESOURCES;\r
    goto ON_EXIT;\r
  }\r
\r
  if (Instance->Dns4CfgData.UseDefaultSetting) {\r
    CopyMem (&(Token.ListenPoints[0].ListenAddress), &(InterfaceInfo->StationAddress), sizeof (EFI_IPv4_ADDRESS));\r
    CopyMem (&(Token.ListenPoints[0].SubnetMask), &(InterfaceInfo->SubnetMask), sizeof (EFI_IPv4_ADDRESS));\r
  } else {\r
    CopyMem (&(Token.ListenPoints[0].ListenAddress), &(Instance->Dns4CfgData.StationIp), sizeof (EFI_IPv4_ADDRESS));\r
    CopyMem (&(Token.ListenPoints[0].SubnetMask), &(Instance->Dns4CfgData.SubnetMask), sizeof (EFI_IPv4_ADDRESS));\r
  }\r
\r
  Token.ListenPoints[0].ListenPort = 68;\r
\r
  Token.TimeoutValue = DNS_TIME_TO_GETMAP;\r
\r
  DnsInitSeedPacket (&SeedPacket, InterfaceInfo);\r
\r
  ParaList[0] = AllocateZeroPool (sizeof (EFI_DHCP4_PACKET_OPTION));\r
  if (ParaList[0] == NULL) {\r
    Status = EFI_OUT_OF_RESOURCES;\r
    goto ON_EXIT;\r
  }\r
\r
  ParaList[0]->OpCode  = DHCP4_TAG_TYPE;\r
  ParaList[0]->Length  = 1;\r
  ParaList[0]->Data[0] = DHCP4_MSG_REQUEST;\r
\r
  ParaList[1] = AllocateZeroPool (sizeof (EFI_DHCP4_PACKET_OPTION));\r
  if (ParaList[1] == NULL) {\r
    Status = EFI_OUT_OF_RESOURCES;\r
    goto ON_EXIT;\r
  }\r
\r
  ParaList[1]->OpCode  = DHCP4_TAG_PARA_LIST;\r
  ParaList[1]->Length  = 1;\r
  ParaList[1]->Data[0] = DHCP4_TAG_DNS_SERVER;\r
\r
  Status = Dhcp4->Build (Dhcp4, &SeedPacket, 0, NULL, 2, ParaList, &Token.Packet);\r
\r
  Token.Packet->Dhcp4.Header.Xid = HTONL (NET_RANDOM (NetRandomInitSeed ()));\r
\r
  Token.Packet->Dhcp4.Header.Reserved = HTONS ((UINT16)0x8000);\r
\r
  if (Instance->Dns4CfgData.UseDefaultSetting) {\r
    CopyMem (&(Token.Packet->Dhcp4.Header.ClientAddr), &(InterfaceInfo->StationAddress), sizeof (EFI_IPv4_ADDRESS));\r
  } else {\r
    CopyMem (&(Token.Packet->Dhcp4.Header.ClientAddr), &(Instance->Dns4CfgData.StationIp), sizeof (EFI_IPv4_ADDRESS));\r
  }\r
\r
  CopyMem (Token.Packet->Dhcp4.Header.ClientHwAddr, &(InterfaceInfo->HwAddress), InterfaceInfo->HwAddressSize);\r
\r
  Token.Packet->Dhcp4.Header.HwAddrLen = (UINT8)(InterfaceInfo->HwAddressSize);\r
\r
  //\r
  // TransmitReceive Token\r
  //\r
  Status = Dhcp4->TransmitReceive (Dhcp4, &Token);\r
  if (EFI_ERROR (Status)) {\r
    goto ON_EXIT;\r
  }\r
\r
  //\r
  // Poll the packet\r
  //\r
  do {\r
    Status = Mnp->Poll (Mnp);\r
  } while (!IsDone);\r
\r
  //\r
  // Parse the ACK to get required information if received done.\r
  //\r
  if (IsDone && !EFI_ERROR (Token.Status)) {\r
    for (Index = 0; Index < Token.ResponseCount; Index++) {\r
      Status = ParseDhcp4Ack (Dhcp4, &Token.ResponseList[Index], &DnsServerInfor);\r
      if (!EFI_ERROR (Status)) {\r
        break;\r
      }\r
    }\r
\r
    *DnsServerList = DnsServerInfor.ServerList;\r
  } else {\r
    Status = Token.Status;\r
  }\r
\r
ON_EXIT:\r
\r
  if (Data != NULL) {\r
    FreePool (Data);\r
  }\r
\r
  for (Index = 0; Index < 2; Index++) {\r
    if (ParaList[Index] != NULL) {\r
      FreePool (ParaList[Index]);\r
    }\r
  }\r
\r
  if (Token.ListenPoints) {\r
    FreePool (Token.ListenPoints);\r
  }\r
\r
  if (Token.Packet) {\r
    FreePool (Token.Packet);\r
  }\r
\r
  if (Token.ResponseList != NULL) {\r
    FreePool (Token.ResponseList);\r
  }\r
\r
  if (Token.CompletionEvent != NULL) {\r
    gBS->CloseEvent (Token.CompletionEvent);\r
  }\r
\r
  if (Dhcp4 != NULL) {\r
    Dhcp4->Stop (Dhcp4);\r
    Dhcp4->Configure (Dhcp4, NULL);\r
\r
    gBS->CloseProtocol (\r
           Dhcp4Handle,\r
           &gEfiDhcp4ProtocolGuid,\r
           Image,\r
           Controller\r
           );\r
  }\r
\r
  if (Dhcp4Handle != NULL) {\r
    NetLibDestroyServiceChild (\r
      Controller,\r
      Image,\r
      &gEfiDhcp4ServiceBindingProtocolGuid,\r
      Dhcp4Handle\r
      );\r
  }\r
\r
  if (Mnp != NULL) {\r
    Mnp->Configure (Mnp, NULL);\r
\r
    gBS->CloseProtocol (\r
           MnpChildHandle,\r
           &gEfiManagedNetworkProtocolGuid,\r
           Image,\r
           Controller\r
           );\r
  }\r
\r
  NetLibDestroyServiceChild (\r
    Controller,\r
    Image,\r
    &gEfiManagedNetworkServiceBindingProtocolGuid,\r
    MnpChildHandle\r
    );\r
\r
  return Status;\r
}\r
\r
/**\r
  Parse the DHCP ACK to get Dns6 server information.\r
\r
  @param  Image            The handle of the driver image.\r
  @param  Controller       The handle of the controller.\r
  @param  DnsServerCount   Retrieved Dns6 server Ip count.\r
  @param  DnsServerList    Retrieved Dns6 server Ip list.\r
\r
  @retval EFI_SUCCESS           The Dns6 information is got from the DHCP ACK.\r
  @retval EFI_OUT_OF_RESOURCES  Failed to allocate memory.\r
  @retval EFI_NO_MEDIA          There was a media error.\r
  @retval Others                Other errors as indicated.\r
\r
**/\r
EFI_STATUS\r
GetDns6ServerFromDhcp6 (\r
  IN  EFI_HANDLE        Image,\r
  IN  EFI_HANDLE        Controller,\r
  OUT UINT32            *DnsServerCount,\r
  OUT EFI_IPv6_ADDRESS  **DnsServerList\r
  )\r
{\r
  EFI_HANDLE                Dhcp6Handle;\r
  EFI_DHCP6_PROTOCOL        *Dhcp6;\r
  EFI_STATUS                Status;\r
  EFI_STATUS                TimerStatus;\r
  EFI_DHCP6_PACKET_OPTION   *Oro;\r
  EFI_DHCP6_RETRANSMISSION  InfoReqReXmit;\r
  EFI_EVENT                 Timer;\r
  EFI_STATUS                MediaStatus;\r
  DNS6_SERVER_INFOR         DnsServerInfor;\r
\r
  Dhcp6Handle = NULL;\r
  Dhcp6       = NULL;\r
  Oro         = NULL;\r
  Timer       = NULL;\r
\r
  ZeroMem (&DnsServerInfor, sizeof (DNS6_SERVER_INFOR));\r
\r
  DnsServerInfor.ServerCount = DnsServerCount;\r
\r
  //\r
  // Check media status before doing DHCP.\r
  //\r
  MediaStatus = EFI_SUCCESS;\r
  NetLibDetectMediaWaitTimeout (Controller, DNS_CHECK_MEDIA_GET_DHCP_WAITING_TIME, &MediaStatus);\r
  if (MediaStatus != EFI_SUCCESS) {\r
    return EFI_NO_MEDIA;\r
  }\r
\r
  //\r
  // Create a DHCP6 child instance and get the protocol.\r
  //\r
  Status = NetLibCreateServiceChild (\r
             Controller,\r
             Image,\r
             &gEfiDhcp6ServiceBindingProtocolGuid,\r
             &Dhcp6Handle\r
             );\r
  if (EFI_ERROR (Status)) {\r
    return Status;\r
  }\r
\r
  Status = gBS->OpenProtocol (\r
                  Dhcp6Handle,\r
                  &gEfiDhcp6ProtocolGuid,\r
                  (VOID **)&Dhcp6,\r
                  Image,\r
                  Controller,\r
                  EFI_OPEN_PROTOCOL_BY_DRIVER\r
                  );\r
  if (EFI_ERROR (Status)) {\r
    goto ON_EXIT;\r
  }\r
\r
  Oro = AllocateZeroPool (sizeof (EFI_DHCP6_PACKET_OPTION) + 1);\r
  if (Oro == NULL) {\r
    Status = EFI_OUT_OF_RESOURCES;\r
    goto ON_EXIT;\r
  }\r
\r
  //\r
  // Ask the server to reply with DNS options.\r
  // All members in EFI_DHCP6_PACKET_OPTION are in network order.\r
  //\r
  Oro->OpCode  = HTONS (DHCP6_TAG_DNS_REQUEST);\r
  Oro->OpLen   = HTONS (2);\r
  Oro->Data[1] = DHCP6_TAG_DNS_SERVER;\r
\r
  InfoReqReXmit.Irt = 4;\r
  InfoReqReXmit.Mrc = 1;\r
  InfoReqReXmit.Mrt = 10;\r
  InfoReqReXmit.Mrd = 30;\r
\r
  Status = Dhcp6->InfoRequest (\r
                    Dhcp6,\r
                    TRUE,\r
                    Oro,\r
                    0,\r
                    NULL,\r
                    &InfoReqReXmit,\r
                    NULL,\r
                    ParseDhcp6Ack,\r
                    &DnsServerInfor\r
                    );\r
  if (Status == EFI_NO_MAPPING) {\r
    Status = gBS->CreateEvent (EVT_TIMER, TPL_CALLBACK, NULL, NULL, &Timer);\r
    if (EFI_ERROR (Status)) {\r
      goto ON_EXIT;\r
    }\r
\r
    Status = gBS->SetTimer (\r
                    Timer,\r
                    TimerRelative,\r
                    DNS_TIME_TO_GETMAP * TICKS_PER_SECOND\r
                    );\r
\r
    if (EFI_ERROR (Status)) {\r
      goto ON_EXIT;\r
    }\r
\r
    do {\r
      TimerStatus = gBS->CheckEvent (Timer);\r
      if (!EFI_ERROR (TimerStatus)) {\r
        Status = Dhcp6->InfoRequest (\r
                          Dhcp6,\r
                          TRUE,\r
                          Oro,\r
                          0,\r
                          NULL,\r
                          &InfoReqReXmit,\r
                          NULL,\r
                          ParseDhcp6Ack,\r
                          &DnsServerInfor\r
                          );\r
      }\r
    } while (TimerStatus == EFI_NOT_READY);\r
  }\r
\r
  *DnsServerList = DnsServerInfor.ServerList;\r
\r
ON_EXIT:\r
\r
  if (Oro != NULL) {\r
    FreePool (Oro);\r
  }\r
\r
  if (Timer != NULL) {\r
    gBS->CloseEvent (Timer);\r
  }\r
\r
  if (Dhcp6 != NULL) {\r
    gBS->CloseProtocol (\r
           Dhcp6Handle,\r
           &gEfiDhcp6ProtocolGuid,\r
           Image,\r
           Controller\r
           );\r
  }\r
\r
  NetLibDestroyServiceChild (\r
    Controller,\r
    Image,\r
    &gEfiDhcp6ServiceBindingProtocolGuid,\r
    Dhcp6Handle\r
    );\r
\r
  return Status;\r
}\r