/** @file

Copyright (c) 2007, Intel Corporation
All rights reserved. This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution.  The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php

THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.

Module Name:

  PxeBcDhcp.c

Abstract:

  Support for PxeBc dhcp functions


**/


#include "PxeBcImpl.h"

//
// This is a map from the interested DHCP4 option tags' index to the tag value.
//
UINT8 mInterestedDhcp4Tags[PXEBC_DHCP4_TAG_INDEX_MAX] = {
  PXEBC_DHCP4_TAG_BOOTFILE_LEN,
  PXEBC_DHCP4_TAG_VENDOR,
  PXEBC_DHCP4_TAG_OVERLOAD,
  PXEBC_DHCP4_TAG_MSG_TYPE,
  PXEBC_DHCP4_TAG_SERVER_ID,
  PXEBC_DHCP4_TAG_CLASS_ID,
  PXEBC_DHCP4_TAG_BOOTFILE
};


/**
  GC_NOTO: Add function description

  @param  Seed                  GC_NOTO: add argument description
  @param  Udp4                  GC_NOTO: add argument description

  @return GC_NOTO: add return values

**/
VOID
PxeBcInitSeedPacket (
  IN EFI_DHCP4_PACKET  *Seed,
  IN EFI_UDP4_PROTOCOL *Udp4
  )
{
  EFI_SIMPLE_NETWORK_MODE Mode;
  EFI_DHCP4_HEADER        *Header;

  Udp4->GetModeData (Udp4, NULL, NULL, NULL, &Mode);

  Seed->Size    = sizeof (EFI_DHCP4_PACKET);
  Seed->Length  = sizeof (Seed->Dhcp4);

  Header        = &Seed->Dhcp4.Header;

  ZeroMem (Header, sizeof (EFI_DHCP4_HEADER));
  Header->OpCode    = PXEBC_DHCP4_OPCODE_REQUEST;
  Header->HwType    = Mode.IfType;
  Header->HwAddrLen = (UINT8) Mode.HwAddressSize;
  CopyMem (Header->ClientHwAddr, &Mode.CurrentAddress, Header->HwAddrLen);

  Seed->Dhcp4.Magik     = PXEBC_DHCP4_MAGIC;
  Seed->Dhcp4.Option[0] = PXEBC_DHCP4_TAG_EOP;
}


/**
  GC_NOTO: Add function description

  @param  Dst                   GC_NOTO: add argument description
  @param  Src                   GC_NOTO: add argument description

  @return GC_NOTO: add return values

**/
VOID
PxeBcCopyEfiDhcp4Packet (
  IN EFI_DHCP4_PACKET  *Dst,
  IN EFI_DHCP4_PACKET  *Src
  )
{
  ASSERT (Dst->Size >= Src->Length);

  CopyMem (&Dst->Dhcp4, &Src->Dhcp4, Src->Length);
  Dst->Length = Src->Length;
}


/**
  GC_NOTO: Add function description

  @param  Private               GC_NOTO: add argument description
  @param  OfferIndex            GC_NOTO: add argument description

  @return GC_NOTO: add return values

**/
VOID
PxeBcCopyProxyOffer (
  IN PXEBC_PRIVATE_DATA  *Private,
  IN UINT32              OfferIndex
  )
{
  EFI_PXE_BASE_CODE_MODE  *Mode;
  EFI_DHCP4_PACKET        *Offer;

  ASSERT (OfferIndex < Private->NumOffers);

  Mode  = Private->PxeBc.Mode;
  Offer = &Private->Dhcp4Offers[OfferIndex].Packet.Offer;

  PxeBcCopyEfiDhcp4Packet (&Private->ProxyOffer.Packet.Offer, Offer);
  CopyMem (&Mode->ProxyOffer, &Offer->Dhcp4, Offer->Length);
  Mode->ProxyOfferReceived = TRUE;

  PxeBcParseCachedDhcpPacket (&Private->ProxyOffer);
}


/**
  Parse the cached dhcp packet.

  @param  CachedPacket          Pointer to cached dhcp packet

  @return TRUE  : Success to parse and validation
  @return FALSE : Fail to parse or validation

**/
BOOLEAN
PxeBcParseCachedDhcpPacket (
  IN PXEBC_CACHED_DHCP4_PACKET  *CachedPacket
  )
{
  EFI_DHCP4_PACKET        *Offer;
  EFI_DHCP4_PACKET_OPTION **Options;
  EFI_DHCP4_PACKET_OPTION *Option;
  UINT8                   OfferType;
  UINTN                   Index;

  CachedPacket->IsPxeOffer = FALSE;
  ZeroMem (CachedPacket->Dhcp4Option, sizeof (CachedPacket->Dhcp4Option));
  ZeroMem (&CachedPacket->PxeVendorOption, sizeof (CachedPacket->PxeVendorOption));

  Offer   = &CachedPacket->Packet.Offer;
  Options = CachedPacket->Dhcp4Option;

  //
  // Parse interested dhcp options and store their pointers in CachedPacket->Dhcp4Option.
  //
  for (Index = 0; Index < PXEBC_DHCP4_TAG_INDEX_MAX; Index++) {
    Options[Index] = PxeBcParseExtendOptions (
                      Offer->Dhcp4.Option,
                      GET_OPTION_BUFFER_LEN (Offer),
                      mInterestedDhcp4Tags[Index]
                      );
  }

  //
  // Check whether is an offer with PXEClient or not.
  //
  Option = Options[PXEBC_DHCP4_TAG_INDEX_CLASS_ID];
  if ((Option != NULL) && (Option->Length >= 9) &&
    (CompareMem (Option->Data, DEFAULT_CLASS_ID_DATA, 9) == 0)) {

    CachedPacket->IsPxeOffer = TRUE;
  }

  //
  // Parse pxe vendor options and store their content/pointers in CachedPacket->PxeVendorOption.
  //
  Option = Options[PXEBC_DHCP4_TAG_INDEX_VENDOR];
  if (CachedPacket->IsPxeOffer && (Option != NULL)) {

    if (!PxeBcParseVendorOptions (Option, &CachedPacket->PxeVendorOption)) {
      return FALSE;
    }
  }

  //
  // Check whether bootfilename/serverhostname overloaded (See details in dhcp spec).
  // If overloaded, parse this buffer as nested dhcp options, or just parse bootfilename/
  // serverhostname option.
  //
  Option = Options[PXEBC_DHCP4_TAG_INDEX_OVERLOAD];
  if ((Option != NULL) && (Option->Data[0] & PXEBC_DHCP4_OVERLOAD_FILE)) {

    Options[PXEBC_DHCP4_TAG_INDEX_BOOTFILE] = PxeBcParseExtendOptions (
                                                (UINT8 *) Offer->Dhcp4.Header.BootFileName,
                                                sizeof (Offer->Dhcp4.Header.BootFileName),
                                                PXEBC_DHCP4_TAG_BOOTFILE
                                                );

  } else if ((Options[PXEBC_DHCP4_TAG_INDEX_BOOTFILE] == NULL) &&
            (Offer->Dhcp4.Header.BootFileName[0] != 0)) {
    //
    // If the bootfile is not present and bootfilename is present in dhcp packet, just parse it.
    // And do not count dhcp option header, or else will destory the serverhostname.
    //
    Options[PXEBC_DHCP4_TAG_INDEX_BOOTFILE] = (EFI_DHCP4_PACKET_OPTION *) (&Offer->Dhcp4.Header.BootFileName[0] -
                                            EFI_FIELD_OFFSET (EFI_DHCP4_PACKET_OPTION, Data[0]));

  }

  //
  // Determine offer type of the dhcp packet.
  //
  Option = Options[PXEBC_DHCP4_TAG_INDEX_MSG_TYPE];
  if ((Option == NULL) || (Option->Data[0] == 0)) {
    //
    // It's a bootp offer
    //
    Option = CachedPacket->Dhcp4Option[PXEBC_DHCP4_TAG_INDEX_BOOTFILE];
    if (Option == NULL) {
      //
      // bootp offer without bootfilename, discard it.
      //
      return FALSE;
    }

    OfferType = DHCP4_PACKET_TYPE_BOOTP;

  } else {

    if (IS_VALID_DISCOVER_VENDOR_OPTION (CachedPacket->PxeVendorOption.BitMap)) {
      //
      // It's a pxe10 offer with PXEClient and discover vendor option.
      //
      OfferType = DHCP4_PACKET_TYPE_PXE10;
    } else if (IS_VALID_MTFTP_VENDOR_OPTION (CachedPacket->PxeVendorOption.BitMap)) {
      //
      // It's a wfm11a offer with PXEClient and mtftp vendor option, and
      // return false since mtftp not supported currently.
      //
      return FALSE;
    } else {
      //
      // If the binl offer with only PXEClient.
      //
      OfferType = (UINT8) ((CachedPacket->IsPxeOffer) ? DHCP4_PACKET_TYPE_BINL : DHCP4_PACKET_TYPE_DHCP_ONLY);
    }
  }

  CachedPacket->OfferType = OfferType;

  return TRUE;
}


/**
  GC_NOTO: Add function description

  @param  Private               GC_NOTO: add argument description
  @param  Index                 GC_NOTO: add argument description

  @return GC_NOTO: add return values

**/
BOOLEAN
PxeBcTryBinl (
  IN PXEBC_PRIVATE_DATA  *Private,
  IN UINT32              Index
  )
{
  EFI_DHCP4_PACKET          *Offer;
  EFI_IP_ADDRESS            ServerIp;
  EFI_STATUS                Status;
  PXEBC_CACHED_DHCP4_PACKET *CachedPacket;
  EFI_DHCP4_PACKET          *Reply;

  ASSERT (Private->Dhcp4Offers[Index].OfferType == DHCP4_PACKET_TYPE_BINL);

  Offer = &Private->Dhcp4Offers[Index].Packet.Offer;
  if (Offer->Dhcp4.Header.ServerAddr.Addr[0] == 0) {
    //
    // next server ip address is zero, use server id option instead.
    //
    CopyMem (
      &ServerIp.Addr[0],
      Private->Dhcp4Offers[Index].Dhcp4Option[PXEBC_DHCP4_TAG_INDEX_SERVER_ID]->Data,
      sizeof (EFI_IPv4_ADDRESS)
      );
  } else {
    //
    // use next server ip address.
    //
    CopyMem (&ServerIp.Addr[0], &Offer->Dhcp4.Header.ServerAddr, sizeof (EFI_IPv4_ADDRESS));
  }

  CachedPacket = &Private->ProxyOffer;
  Reply        = &CachedPacket->Packet.Offer;

  Status = PxeBcDiscvBootService (
            Private,
            0,
            NULL,
            FALSE,
            &ServerIp,
            0,
            NULL,
            FALSE,
            Reply
            );
  if (EFI_ERROR (Status)) {
    return FALSE;
  }

  if (!PxeBcParseCachedDhcpPacket (CachedPacket)) {
    return FALSE;
  }

  if ((CachedPacket->OfferType != DHCP4_PACKET_TYPE_PXE10) &&
      (CachedPacket->Dhcp4Option[PXEBC_DHCP4_TAG_INDEX_BOOTFILE] == NULL)) {
    //
    // This BINL ack doesn't have discovery options set or bootfile name
    // specified.
    //
    return FALSE;
  }

  Private->PxeBc.Mode->ProxyOfferReceived = TRUE;
  CopyMem (&Private->PxeBc.Mode->ProxyOffer, &Reply->Dhcp4, Reply->Length);

  return TRUE;
}


/**
  GC_NOTO: Add function description

  @param  Private               GC_NOTO: add argument description
  @param  OfferIndex            GC_NOTO: add argument description

  @return GC_NOTO: add return values

**/
BOOLEAN
PxeBcTryBinlProxy (
  IN  PXEBC_PRIVATE_DATA  *Private,
  OUT UINT32              *OfferIndex
  )
{
  UINT32  Index;

  for (Index = 0; Index < Private->ProxyIndex[DHCP4_PACKET_TYPE_BINL]; Index++) {

    *OfferIndex = Private->BinlIndex[Index];
    //
    // Try this BINL proxy offer
    //
    if (PxeBcTryBinl (Private, *OfferIndex)) {
      return TRUE;
    }
  }

  return FALSE;
}


/**
  GC_NOTO: Add function description

  @param  Private               GC_NOTO: add argument description

  @return GC_NOTO: add return values

**/
EFI_STATUS
PxeBcCheckSelectedOffer (
  IN PXEBC_PRIVATE_DATA  *Private
  )
{
  PXEBC_CACHED_DHCP4_PACKET *SelectedOffer;
  EFI_DHCP4_PACKET_OPTION   **Options;
  UINT32                    Index;
  EFI_DHCP4_PACKET          *Offer;
  UINT32                    ProxyOfferIndex;
  EFI_STATUS                Status;
  EFI_PXE_BASE_CODE_MODE    *Mode;
  EFI_DHCP4_PACKET          *Ack;

  ASSERT (Private->SelectedOffer != 0);

  Status        = EFI_SUCCESS;
  SelectedOffer = &Private->Dhcp4Offers[Private->SelectedOffer - 1];
  Options       = SelectedOffer->Dhcp4Option;

  if (SelectedOffer->OfferType == DHCP4_PACKET_TYPE_BINL) {
    //
    // The addresses are acquired from a BINL dhcp offer, try BINL to get
    // the bootfile name
    //
    if (!PxeBcTryBinl (Private, Private->SelectedOffer - 1)) {
      Status = EFI_NO_RESPONSE;
    }
  } else if ((SelectedOffer->OfferType == DHCP4_PACKET_TYPE_DHCP_ONLY) &&
           (Options[PXEBC_DHCP4_TAG_INDEX_BOOTFILE] == NULL)) {
    //
    // The selected offer to finish the D.O.R.A. is a DHCP only offer and
    // bootfile name is not provided in this offer, we need try proxy offers
    // to get the bootfile name or the discovery info
    //
    ProxyOfferIndex = Private->NumOffers;

    if (Private->SortOffers) {
      //
      // Choose proxy offer from the type we stored during DHCP offer selection
      //
      ASSERT (Private->ProxyIndex[Private->ProxyOfferType] > 0);

      if (Private->ProxyOfferType == DHCP4_PACKET_TYPE_BINL) {
        //
        // We buffer all received BINL proxy offers, try them all one by one
        //
        if (!PxeBcTryBinlProxy (Private, &ProxyOfferIndex)) {
          Status = EFI_NO_RESPONSE;
        }
      } else {
        //
        // For other types, only one proxy offer is buffered.
        //
        ProxyOfferIndex = Private->ProxyIndex[Private->ProxyOfferType] - 1;
      }
    } else {
      //
      // Choose proxy offer in the received order.
      //
      Status = EFI_NO_RESPONSE;

      for (Index = 0; Index < Private->NumOffers; Index++) {

        Offer = &Private->Dhcp4Offers[Index].Packet.Offer;
        if (!IS_PROXY_DHCP_OFFER (Offer)) {
          //
          // Skip non proxy dhcp offers.
          //
          continue;
        }

        if (Private->Dhcp4Offers[Index].OfferType == DHCP4_PACKET_TYPE_BINL) {
          //
          // Try BINL
          //
          if (!PxeBcTryBinl (Private, Index)) {
            //
            // Failed, skip to the next offer
            //
            continue;
          }
        }

        Status = EFI_SUCCESS;
        break;
      }
    }

    if (!EFI_ERROR (Status) && (Private->ProxyOfferType != DHCP4_PACKET_TYPE_BINL)) {
      //
      // Copy the proxy offer to Mode and set the flag
      //
      PxeBcCopyProxyOffer (Private, ProxyOfferIndex);
    }
  }

  if (!EFI_ERROR (Status)) {
    //
    // Everything is OK, set the flag and copy the DHCP packets.
    //
    Mode  = Private->PxeBc.Mode;
    Offer = &SelectedOffer->Packet.Offer;

    //
    // The discover packet is already copied, just set flag here.
    //
    Mode->DhcpDiscoverValid = TRUE;

    Ack                     = &Private->Dhcp4Ack.Packet.Ack;
    if (SelectedOffer->OfferType == DHCP4_PACKET_TYPE_BOOTP) {
      //
      // Other type of ACK is already cached. Bootp is special that we should
      // use the bootp reply as the ACK and put it into the DHCP_ONLY buffer.
      //
      PxeBcCopyEfiDhcp4Packet (&Private->Dhcp4Ack.Packet.Ack, Offer);
    }

    PxeBcParseCachedDhcpPacket (&Private->Dhcp4Ack);

    Mode->DhcpAckReceived = TRUE;

    //
    // Copy the dhcp ack.
    //
    CopyMem (&Mode->DhcpAck, &Ack->Dhcp4, Ack->Length);
  }

  return Status;
}


/**
  GC_NOTO: Add function description

  @param  Private               GC_NOTO: add argument description
  @param  RcvdOffer             GC_NOTO: add argument description

  @return GC_NOTO: add return values

**/
VOID
PxeBcCacheDhcpOffer (
  IN PXEBC_PRIVATE_DATA  *Private,
  IN EFI_DHCP4_PACKET    *RcvdOffer
  )
{
  PXEBC_CACHED_DHCP4_PACKET *CachedOffer;
  EFI_DHCP4_PACKET          *Offer;
  UINT8                     OfferType;

  CachedOffer = &Private->Dhcp4Offers[Private->NumOffers];
  Offer       = &CachedOffer->Packet.Offer;

  //
  // Cache the orignal dhcp packet
  //
  PxeBcCopyEfiDhcp4Packet (Offer, RcvdOffer);

  //
  // Parse and validate the options (including dhcp option and vendor option)
  //
  if (!PxeBcParseCachedDhcpPacket (CachedOffer)) {
    return ;
  }

  OfferType = CachedOffer->OfferType;

  if (OfferType == DHCP4_PACKET_TYPE_BOOTP) {

    if (Private->BootpIndex != 0) {
      //
      // Only cache the first bootp offer, discard others.
      //
      return ;
    } else {
      //
      // Take as a dhcp only offer, but record index specifically.
      //
      Private->BootpIndex = Private->NumOffers + 1;
    }
  } else {

    if (IS_PROXY_DHCP_OFFER (Offer)) {
      //
      // It's a proxy dhcp offer with no your address, including pxe10, wfm11a or binl offer.
      //
      if (OfferType == DHCP4_PACKET_TYPE_BINL) {
        //
        // Cache all binl offers.
        //
        Private->BinlIndex[Private->ProxyIndex[DHCP4_PACKET_TYPE_BINL]] = Private->NumOffers;
        Private->ProxyIndex[DHCP4_PACKET_TYPE_BINL]++;
      } else if (Private->ProxyIndex[OfferType] != 0) {
        //
        // Only cache the first pxe10/wfm11a offers each, discard the others.
        //
        return ;
      } else {
        //
        // Record index of the proxy dhcp offer with type other than binl.
        //
        Private->ProxyIndex[OfferType] = Private->NumOffers + 1;
      }
    } else {
      //
      // It's a dhcp offer with your address.
      //
      Private->OfferIndex[OfferType][Private->ServerCount[OfferType]] = Private->NumOffers;
      Private->ServerCount[OfferType]++;
    }
  }

  //
  // Count the accepted offers.
  //
  Private->NumOffers++;
}


/**
  GC_NOTO: Add function description

  @param  Private               GC_NOTO: add argument description

  @return GC_NOTO: add return values

**/
VOID
PxeBcSelectOffer (
  IN PXEBC_PRIVATE_DATA  *Private
  )
{
  UINT32            Index;
  UINT32            OfferIndex;
  EFI_DHCP4_PACKET  *Offer;
  BOOLEAN           GotProxyOffer;

  Private->SelectedOffer = 0;

  if (Private->SortOffers) {
    //
    // Select offer according to the priority
    //
    if (Private->ServerCount[DHCP4_PACKET_TYPE_PXE10] > 0) {
      //
      // DHCP with PXE10
      //
      Private->SelectedOffer = Private->OfferIndex[DHCP4_PACKET_TYPE_PXE10][0] + 1;

    } else if (Private->ServerCount[DHCP4_PACKET_TYPE_WFM11A] > 0) {
      //
      // DHCP with WfM
      //
      Private->SelectedOffer = Private->OfferIndex[DHCP4_PACKET_TYPE_WFM11A][0] + 1;

    } else if ((Private->ProxyIndex[DHCP4_PACKET_TYPE_PXE10] > 0) &&
             (Private->ServerCount[DHCP4_PACKET_TYPE_DHCP_ONLY] > 0)
            ) {
      //
      // DHCP only and proxy DHCP with PXE10
      //
      Private->SelectedOffer = Private->OfferIndex[DHCP4_PACKET_TYPE_DHCP_ONLY][0] + 1;
      Private->ProxyOfferType     = DHCP4_PACKET_TYPE_PXE10;

    } else if ((Private->ProxyIndex[DHCP4_PACKET_TYPE_WFM11A] > 0) &&
             (Private->ServerCount[DHCP4_PACKET_TYPE_DHCP_ONLY] > 0)
            ) {
      //
      // DHCP only and proxy DHCP with WfM
      //
      Private->SelectedOffer = Private->OfferIndex[DHCP4_PACKET_TYPE_DHCP_ONLY][0] + 1;
      Private->ProxyOfferType     = DHCP4_PACKET_TYPE_WFM11A;

    } else if (Private->ServerCount[DHCP4_PACKET_TYPE_BINL] > 0) {
      //
      // DHCP with BINL
      //
      Private->SelectedOffer = Private->OfferIndex[DHCP4_PACKET_TYPE_BINL][0] + 1;

    } else if ((Private->ProxyIndex[DHCP4_PACKET_TYPE_BINL] > 0) &&
             (Private->ServerCount[DHCP4_PACKET_TYPE_DHCP_ONLY] > 0)
            ) {
      //
      // DHCP only and proxy DHCP with BINL
      //
      Private->SelectedOffer = Private->OfferIndex[DHCP4_PACKET_TYPE_DHCP_ONLY][0] + 1;
      Private->ProxyOfferType     = DHCP4_PACKET_TYPE_BINL;

    } else {
      //
      // Try offers with bootfile
      //
      for (Index = 0; Index < Private->ServerCount[DHCP4_PACKET_TYPE_DHCP_ONLY]; Index++) {
        //
        // Select the first DHCP only offer with bootfile
        //
        OfferIndex = Private->OfferIndex[DHCP4_PACKET_TYPE_DHCP_ONLY][Index];
        if (Private->Dhcp4Offers[OfferIndex].Dhcp4Option[PXEBC_DHCP4_TAG_INDEX_BOOTFILE] != NULL) {
          Private->SelectedOffer = OfferIndex + 1;
          break;
        }
      }

      if (Private->SelectedOffer == 0) {
        //
        // Select the Bootp reply with bootfile if any
        //
        Private->SelectedOffer = Private->BootpIndex;
      }
    }
  } else {
    //
    // Try the offers in the received order.
    //
    GotProxyOffer = FALSE;
    for (Index = 0; Index < DHCP4_PACKET_TYPE_MAX; Index++) {

      GotProxyOffer = (BOOLEAN) (Private->ProxyIndex[Index] > 0);
      if (GotProxyOffer) {
        break;
      }
    }

    for (Index = 0; Index < Private->NumOffers; Index++) {

      Offer = &Private->Dhcp4Offers[Index].Packet.Offer;

      if (IS_PROXY_DHCP_OFFER (Offer)) {
        //
        // Skip proxy offers
        //
        continue;
      }

      if ((Private->Dhcp4Offers[Index].OfferType == DHCP4_PACKET_TYPE_DHCP_ONLY) &&
          ((!GotProxyOffer) && (Private->Dhcp4Offers[Index].Dhcp4Option[PXEBC_DHCP4_TAG_INDEX_BOOTFILE] == NULL))) {
        //
        // DHCP only offer but no proxy offer received and no bootfile option in this offer
        //
        continue;
      }

      Private->SelectedOffer = Index + 1;
      break;
    }
  }
}


/**
  GC_NOTO: Add function description

  @param  This                  GC_NOTO: add argument description
  @param  Context               GC_NOTO: add argument description
  @param  CurrentState          GC_NOTO: add argument description
  @param  Dhcp4Event            GC_NOTO: add argument description
  @param  Packet                GC_NOTO: add argument description
  @param  NewPacket             GC_NOTO: add argument description

  @retval EFI_SUCCESS           GC_NOTO: Add description for return value
  @retval EFI_ABORTED           GC_NOTO: Add description for return value

**/
EFI_STATUS
PxeBcDhcpCallBack (
  IN EFI_DHCP4_PROTOCOL                * This,
  IN VOID                              *Context,
  IN EFI_DHCP4_STATE                   CurrentState,
  IN EFI_DHCP4_EVENT                   Dhcp4Event,
  IN EFI_DHCP4_PACKET                  * Packet OPTIONAL,
  OUT EFI_DHCP4_PACKET                 **NewPacket OPTIONAL
  )
{
  PXEBC_PRIVATE_DATA                  *Private;
  EFI_PXE_BASE_CODE_MODE              *Mode;
  EFI_PXE_BASE_CODE_CALLBACK_PROTOCOL *Callback;
  EFI_DHCP4_PACKET_OPTION             *MaxMsgSize;
  UINT16                              Value;
  EFI_STATUS                          Status;
  BOOLEAN                             Received;
  CHAR8                               *SystemSerialNumber;
  EFI_DHCP4_HEADER                    *DhcpHeader;

  if ((Dhcp4Event != Dhcp4RcvdOffer) &&
      (Dhcp4Event != Dhcp4SelectOffer) &&
      (Dhcp4Event != Dhcp4SendDiscover) &&
      (Dhcp4Event != Dhcp4RcvdAck) &&
      (Dhcp4Event != Dhcp4SendRequest)) {
    return EFI_SUCCESS;
  }

  Private   = (PXEBC_PRIVATE_DATA *) Context;
  Mode      = Private->PxeBc.Mode;
  Callback  = Private->PxeBcCallback;

  //
  // Override the Maximum DHCP Message Size.
  //
  MaxMsgSize = PxeBcParseExtendOptions (
                Packet->Dhcp4.Option,
                GET_OPTION_BUFFER_LEN (Packet),
                PXEBC_DHCP4_TAG_MAXMSG
                );
  if (MaxMsgSize != NULL) {
    Value = HTONS (PXEBC_DHCP4_MAX_PACKET_SIZE);
    CopyMem (MaxMsgSize->Data, &Value, sizeof (Value));
  }

  if ((Dhcp4Event != Dhcp4SelectOffer) && (Callback != NULL)) {
    Received = (BOOLEAN) ((Dhcp4Event == Dhcp4RcvdOffer) || (Dhcp4Event == Dhcp4RcvdAck));
    Status = Callback->Callback (
                        Callback,
                        Private->Function,
                        Received,
                        Packet->Length,
                        (EFI_PXE_BASE_CODE_PACKET *) &Packet->Dhcp4
                        );
    if (Status != EFI_PXE_BASE_CODE_CALLBACK_STATUS_CONTINUE) {
      return EFI_ABORTED;
    }
  }

  Status = EFI_SUCCESS;

  switch (Dhcp4Event) {

  case Dhcp4SendDiscover:
  case Dhcp4SendRequest:
    if (Mode->SendGUID) {
      //
      // send the system GUID instead of the MAC address as the hardware address
      // in the DHCP packet header.
      //
      DhcpHeader = &Packet->Dhcp4.Header;

      if (EFI_ERROR (GetSmbiosSystemGuidAndSerialNumber ((EFI_GUID *) DhcpHeader->ClientHwAddr, &SystemSerialNumber))) {
        //
        // GUID not yet set - send all 0xff's to show programable (via SetVariable)
        // SetMem(DHCPV4_OPTIONS_BUFFER.DhcpPlatformId.Guid, sizeof(EFI_GUID), 0xff);
        // GUID not yet set - send all 0's to show not programable
        //
        ZeroMem (DhcpHeader->ClientHwAddr, sizeof (EFI_GUID));
      }

      DhcpHeader->HwAddrLen = sizeof (EFI_GUID);
    }

    if (Dhcp4Event == Dhcp4SendDiscover) {
      //
      // Cache the dhcp discover packet, of which some information will be used later.
      //
      CopyMem (Mode->DhcpDiscover.Raw, &Packet->Dhcp4, Packet->Length);
    }

    break;

  case Dhcp4RcvdOffer:
    Status = EFI_NOT_READY;
    if (Private->NumOffers < PXEBC_MAX_OFFER_NUM) {
      //
      // Cache the dhcp offers in Private->Dhcp4Offers[]
      //
      PxeBcCacheDhcpOffer (Private, Packet);
    }

    break;

  case Dhcp4SelectOffer:
    //
    // Select an offer, if succeeded, Private->SelectedOffer points to
    // the index of the selected one.
    //
    PxeBcSelectOffer (Private);

    if (Private->SelectedOffer == 0) {
      Status = EFI_ABORTED;
    } else {
      *NewPacket = &Private->Dhcp4Offers[Private->SelectedOffer - 1].Packet.Offer;
    }

    break;

  case Dhcp4RcvdAck:
    //
    // Cache Ack
    //
    ASSERT (Private->SelectedOffer != 0);

    PxeBcCopyEfiDhcp4Packet (&Private->Dhcp4Ack.Packet.Ack, Packet);
    break;

  default:
    break;
  }

  return Status;
}


/**
  GC_NOTO: Add function description

  @param  Private               GC_NOTO: add argument description
  @param  OptList               GC_NOTO: add argument description
  @param  IsDhcpDiscover        GC_NOTO: add argument description

  @return GC_NOTO: add return values

**/
UINT32
PxeBcBuildDhcpOptions (
  IN PXEBC_PRIVATE_DATA            *Private,
  IN EFI_DHCP4_PACKET_OPTION       **OptList,
  IN BOOLEAN                       IsDhcpDiscover
  )
{
  UINT32                    Index;
  PXEBC_DHCP4_OPTION_ENTRY  OptEnt;
  UINT16                    Value;
  CHAR8                     *SystemSerialNumber;

  Index       = 0;
  OptList[0]  = (EFI_DHCP4_PACKET_OPTION *) Private->OptionBuffer;

  if (!IsDhcpDiscover) {
    //
    // Append message type.
    //
    OptList[Index]->OpCode  = PXEBC_DHCP4_TAG_MSG_TYPE;
    OptList[Index]->Length  = 1;
    OptEnt.Mesg             = (PXEBC_DHCP4_OPTION_MESG *) OptList[Index]->Data;
    OptEnt.Mesg->Type       = PXEBC_DHCP4_MSG_TYPE_REQUEST;
    Index++;
    OptList[Index]          = GET_NEXT_DHCP_OPTION (OptList[Index - 1]);

    //
    // Append max message size.
    //
    OptList[Index]->OpCode  = PXEBC_DHCP4_TAG_MAXMSG;
    OptList[Index]->Length  = sizeof (PXEBC_DHCP4_OPTION_MAX_MESG_SIZE);
    OptEnt.MaxMesgSize      = (PXEBC_DHCP4_OPTION_MAX_MESG_SIZE *) OptList[Index]->Data;
    Value                   = NTOHS (PXEBC_DHCP4_MAX_PACKET_SIZE);
    CopyMem (&OptEnt.MaxMesgSize->Size, &Value, sizeof (UINT16));
    Index++;
    OptList[Index]          = GET_NEXT_DHCP_OPTION (OptList[Index - 1]);
  }
  //
  // Parameter request list option.
  //
  OptList[Index]->OpCode    = PXEBC_DHCP4_TAG_PARA_LIST;
  OptList[Index]->Length    = 35;
  OptEnt.Para               = (PXEBC_DHCP4_OPTION_PARA *) OptList[Index]->Data;
  OptEnt.Para->ParaList[0]  = PXEBC_DHCP4_TAG_NETMASK;
  OptEnt.Para->ParaList[1]  = PXEBC_DHCP4_TAG_TIME_OFFSET;
  OptEnt.Para->ParaList[2]  = PXEBC_DHCP4_TAG_ROUTER;
  OptEnt.Para->ParaList[3]  = PXEBC_DHCP4_TAG_TIME_SERVER;
  OptEnt.Para->ParaList[4]  = PXEBC_DHCP4_TAG_NAME_SERVER;
  OptEnt.Para->ParaList[5]  = PXEBC_DHCP4_TAG_DNS_SERVER;
  OptEnt.Para->ParaList[6]  = PXEBC_DHCP4_TAG_HOSTNAME;
  OptEnt.Para->ParaList[7]  = PXEBC_DHCP4_TAG_BOOTFILE_LEN;
  OptEnt.Para->ParaList[8]  = PXEBC_DHCP4_TAG_DOMAINNAME;
  OptEnt.Para->ParaList[9]  = PXEBC_DHCP4_TAG_ROOTPATH;
  OptEnt.Para->ParaList[10] = PXEBC_DHCP4_TAG_EXTEND_PATH;
  OptEnt.Para->ParaList[11] = PXEBC_DHCP4_TAG_EMTU;
  OptEnt.Para->ParaList[12] = PXEBC_DHCP4_TAG_TTL;
  OptEnt.Para->ParaList[13] = PXEBC_DHCP4_TAG_BROADCAST;
  OptEnt.Para->ParaList[14] = PXEBC_DHCP4_TAG_NIS_DOMAIN;
  OptEnt.Para->ParaList[15] = PXEBC_DHCP4_TAG_NIS_SERVER;
  OptEnt.Para->ParaList[16] = PXEBC_DHCP4_TAG_NTP_SERVER;
  OptEnt.Para->ParaList[17] = PXEBC_DHCP4_TAG_VENDOR;
  OptEnt.Para->ParaList[18] = PXEBC_DHCP4_TAG_REQUEST_IP;
  OptEnt.Para->ParaList[19] = PXEBC_DHCP4_TAG_LEASE;
  OptEnt.Para->ParaList[20] = PXEBC_DHCP4_TAG_SERVER_ID;
  OptEnt.Para->ParaList[21] = PXEBC_DHCP4_TAG_T1;
  OptEnt.Para->ParaList[22] = PXEBC_DHCP4_TAG_T2;
  OptEnt.Para->ParaList[23] = PXEBC_DHCP4_TAG_CLASS_ID;
  OptEnt.Para->ParaList[24] = PXEBC_DHCP4_TAG_TFTP;
  OptEnt.Para->ParaList[25] = PXEBC_DHCP4_TAG_BOOTFILE;
  OptEnt.Para->ParaList[26] = PXEBC_PXE_DHCP4_TAG_UUID;
  OptEnt.Para->ParaList[27] = 0x80;
  OptEnt.Para->ParaList[28] = 0x81;
  OptEnt.Para->ParaList[29] = 0x82;
  OptEnt.Para->ParaList[30] = 0x83;
  OptEnt.Para->ParaList[31] = 0x84;
  OptEnt.Para->ParaList[32] = 0x85;
  OptEnt.Para->ParaList[33] = 0x86;
  OptEnt.Para->ParaList[34] = 0x87;
  Index++;
  OptList[Index]            = GET_NEXT_DHCP_OPTION (OptList[Index - 1]);

  //
  // Append UUID/Guid-based client identifier option
  //
  OptList[Index]->OpCode  = PXEBC_PXE_DHCP4_TAG_UUID;
  OptList[Index]->Length  = sizeof (PXEBC_DHCP4_OPTION_UUID);
  OptEnt.Uuid             = (PXEBC_DHCP4_OPTION_UUID *) OptList[Index]->Data;
  OptEnt.Uuid->Type       = 0;
  Index++;
  OptList[Index]          = GET_NEXT_DHCP_OPTION (OptList[Index - 1]);

  if (EFI_ERROR (GetSmbiosSystemGuidAndSerialNumber ((EFI_GUID *) OptEnt.Uuid->Guid, &SystemSerialNumber))) {
    //
    // GUID not yet set - send all 0xff's to show programable (via SetVariable)
    // SetMem(DHCPV4_OPTIONS_BUFFER.DhcpPlatformId.Guid, sizeof(EFI_GUID), 0xff);
    // GUID not yet set - send all 0's to show not programable
    //
    ZeroMem (OptEnt.Uuid->Guid, sizeof (EFI_GUID));
  }

  //
  // Append client network device interface option
  //
  OptList[Index]->OpCode  = PXEBC_PXE_DHCP4_TAG_UNDI;
  OptList[Index]->Length  = sizeof (PXEBC_DHCP4_OPTION_UNDI);
  OptEnt.Undi             = (PXEBC_DHCP4_OPTION_UNDI *) OptList[Index]->Data;
  OptEnt.Undi->Type       = Private->Nii->Type;
  OptEnt.Undi->MajorVer   = Private->Nii->MajorVer;
  OptEnt.Undi->MinorVer   = Private->Nii->MinorVer;

  Index++;
  OptList[Index] = GET_NEXT_DHCP_OPTION (OptList[Index - 1]);

  //
  // Append client system architecture option
  //
  OptList[Index]->OpCode  = PXEBC_PXE_DHCP4_TAG_ARCH;
  OptList[Index]->Length  = sizeof (PXEBC_DHCP4_OPTION_ARCH);
  OptEnt.Arch             = (PXEBC_DHCP4_OPTION_ARCH *) OptList[Index]->Data;
  Value                   = HTONS (SYS_ARCH);
  CopyMem (&OptEnt.Arch->Type, &Value, sizeof (UINT16));
  Index++;
  OptList[Index]          = GET_NEXT_DHCP_OPTION (OptList[Index - 1]);

  //
  // Append client system architecture option
  //
  OptList[Index]->OpCode  = PXEBC_DHCP4_TAG_CLASS_ID;
  OptList[Index]->Length  = sizeof (PXEBC_DHCP4_OPTION_CLID);
  OptEnt.Clid             = (PXEBC_DHCP4_OPTION_CLID *) OptList[Index]->Data;
  CopyMem (OptEnt.Clid, DEFAULT_CLASS_ID_DATA, sizeof (PXEBC_DHCP4_OPTION_CLID));
  CvtNum (SYS_ARCH, OptEnt.Clid->ArchitectureType, sizeof (OptEnt.Clid->ArchitectureType));
  CopyMem (OptEnt.Clid->InterfaceName, Private->Nii->StringId, sizeof (OptEnt.Clid->InterfaceName));
  CvtNum (Private->Nii->MajorVer, OptEnt.Clid->UndiMajor, sizeof (OptEnt.Clid->UndiMajor));
  CvtNum (Private->Nii->MinorVer, OptEnt.Clid->UndiMinor, sizeof (OptEnt.Clid->UndiMinor));
  Index++;

  return Index;
}


/**
  GC_NOTO: Add function description

  @param  Private               GC_NOTO: add argument description
  @param  Type                  GC_NOTO: add argument description
  @param  Layer                 GC_NOTO: add argument description
  @param  UseBis                GC_NOTO: add argument description
  @param  DestIp                GC_NOTO: add argument description
  @param  IpCount               GC_NOTO: add argument description
  @param  SrvList               GC_NOTO: add argument description
  @param  IsDiscv               GC_NOTO: add argument description
  @param  Reply                 GC_NOTO: add argument description

  @retval EFI_OUT_OF_RESOURCES  GC_NOTO: Add description for return value

**/
EFI_STATUS
PxeBcDiscvBootService (
  IN PXEBC_PRIVATE_DATA                * Private,
  IN UINT16                            Type,
  IN UINT16                            *Layer,
  IN BOOLEAN                           UseBis,
  IN EFI_IP_ADDRESS                    * DestIp,
  IN UINT16                            IpCount,
  IN EFI_PXE_BASE_CODE_SRVLIST         * SrvList,
  IN BOOLEAN                           IsDiscv,
  OUT EFI_DHCP4_PACKET                 * Reply OPTIONAL
  )
{
  EFI_PXE_BASE_CODE_UDP_PORT          Sport;
  EFI_PXE_BASE_CODE_MODE              *Mode;
  EFI_DHCP4_PROTOCOL                  *Dhcp4;
  EFI_DHCP4_TRANSMIT_RECEIVE_TOKEN    Token;
  BOOLEAN                             IsBCast;
  EFI_STATUS                          Status;
  UINT16                              RepIndex;
  UINT16                              SrvIndex;
  UINT16                              TryIndex;
  EFI_DHCP4_LISTEN_POINT              ListenPoint;
  EFI_DHCP4_PACKET                    *Response;
  EFI_DHCP4_PACKET_OPTION             *OptList[PXEBC_DHCP4_MAX_OPTION_NUM];
  UINT32                              OptCount;
  EFI_DHCP4_PACKET_OPTION             *PxeOpt;
  PXEBC_OPTION_BOOT_ITEM              *PxeBootItem;
  UINT8                               VendorOptLen;
  CHAR8                               *SystemSerialNumber;
  EFI_DHCP4_HEADER                    *DhcpHeader;


  Mode      = Private->PxeBc.Mode;
  Dhcp4     = Private->Dhcp4;
  Status    = EFI_SUCCESS;

  ZeroMem (&Token, sizeof (EFI_DHCP4_TRANSMIT_RECEIVE_TOKEN));

  if (DestIp == NULL) {
    Sport   = PXEBC_DHCP4_S_PORT;
    IsBCast = TRUE;
  } else {
    Sport   = PXEBC_BS_DISCOVER_PORT;
    IsBCast = FALSE;
  }

  if (!UseBis && Layer != NULL) {
    *Layer &= EFI_PXE_BASE_CODE_BOOT_LAYER_MASK;
  }

  OptCount = PxeBcBuildDhcpOptions (Private, OptList, FALSE);

  if (IsDiscv) {
    //
    // Add vendor option of PXE_BOOT_ITEM
    //
    VendorOptLen      = (sizeof (EFI_DHCP4_PACKET_OPTION) - 1) * 2 + sizeof (PXEBC_OPTION_BOOT_ITEM) + 1;
    OptList[OptCount] = AllocatePool (VendorOptLen);
    if (OptList[OptCount] == NULL) {
      return EFI_OUT_OF_RESOURCES;
    }

    OptList[OptCount]->OpCode     = PXEBC_DHCP4_TAG_VENDOR;
    OptList[OptCount]->Length     = (UINT8) (VendorOptLen - 2);
    PxeOpt                        = (EFI_DHCP4_PACKET_OPTION *) OptList[OptCount]->Data;
    PxeOpt->OpCode                = PXEBC_VENDOR_TAG_BOOT_ITEM;
    PxeOpt->Length                = sizeof (PXEBC_OPTION_BOOT_ITEM);
    PxeBootItem                   = (PXEBC_OPTION_BOOT_ITEM *) PxeOpt->Data;
    PxeBootItem->Type             = HTONS (Type);
    PxeBootItem->Layer            = HTONS (*Layer);
    PxeOpt->Data[PxeOpt->Length]  = PXEBC_DHCP4_TAG_EOP;

    OptCount++;
  }

  Status = Dhcp4->Build (Dhcp4, &Private->SeedPacket, 0, NULL, OptCount, OptList, &Token.Packet);

  if (IsDiscv) {
    gBS->FreePool (OptList[OptCount - 1]);
  }

  if (EFI_ERROR (Status)) {
    return Status;
  }

  DhcpHeader = &Token.Packet->Dhcp4.Header;
  if (Mode->SendGUID) {
    if (EFI_ERROR (GetSmbiosSystemGuidAndSerialNumber ((EFI_GUID *) DhcpHeader->ClientHwAddr, &SystemSerialNumber))) {
      //
      // GUID not yet set - send all 0's to show not programable
      //
      ZeroMem (DhcpHeader->ClientHwAddr, sizeof (EFI_GUID));
    }

    DhcpHeader->HwAddrLen = sizeof (EFI_GUID);
  }

  Token.Packet->Dhcp4.Header.Xid      = NET_RANDOM (NetRandomInitSeed ());
  Token.Packet->Dhcp4.Header.Reserved = (UINT16) ((IsBCast) ? 0xf000 : 0x0);
  CopyMem (&Token.Packet->Dhcp4.Header.ClientAddr, &Private->StationIp, sizeof (EFI_IPv4_ADDRESS));

  Token.RemotePort = Sport;

  if (DestIp == NULL) {
    SetMem (&Token.RemoteAddress, sizeof (EFI_IPv4_ADDRESS), 0xff);
  } else {
    CopyMem (&Token.RemoteAddress, DestIp, sizeof (EFI_IPv4_ADDRESS));
  }

  CopyMem (&Token.GatewayAddress, &Private->GatewayIp, sizeof (EFI_IPv4_ADDRESS));

  if (!IsBCast) {
    Token.ListenPointCount            = 1;
    Token.ListenPoints                = &ListenPoint;
    Token.ListenPoints[0].ListenPort  = PXEBC_BS_DISCOVER_PORT;
    CopyMem (&Token.ListenPoints[0].ListenAddress, &Private->StationIp, sizeof(EFI_IPv4_ADDRESS));
    CopyMem (&Token.ListenPoints[0].SubnetMask, &Private->SubnetMask, sizeof(EFI_IPv4_ADDRESS));
  }
  //
  // Send Pxe Discover
  //
  for (TryIndex = 1; TryIndex <= PXEBC_BOOT_REQUEST_RETRIES; TryIndex++) {

    Token.TimeoutValue  = PXEBC_BOOT_REQUEST_TIMEOUT * TryIndex;

    Status              = Dhcp4->TransmitReceive (Dhcp4, &Token);

    if (Token.Status != EFI_TIMEOUT) {
      break;
    }
  }

  if (!EFI_ERROR (Status)) {
    //
    // Find Pxe Reply
    //
    RepIndex  = 0;
    SrvIndex  = 0;
    Response  = Token.ResponseList;

    while (RepIndex < Token.ResponseCount) {

      while (SrvIndex < IpCount) {

        if (SrvList[SrvIndex].AcceptAnyResponse) {
          break;
        }

        if ((SrvList[SrvIndex].Type == Type) && EFI_IP4_EQUAL (&(Response->Dhcp4.Header.ServerAddr), &(Private->ServerIp))) {
          break;
        }

        SrvIndex++;
      }

      if ((IpCount != SrvIndex) || (IpCount == 0)) {
        break;
      }

      SrvIndex = 0;
      RepIndex++;

      Response = (EFI_DHCP4_PACKET *) ((UINT8 *) Response + Response->Size);
    }

    if (RepIndex < Token.ResponseCount) {

      if (Reply != NULL) {
        PxeBcCopyEfiDhcp4Packet (Reply, Response);
      }

      if (IsDiscv) {
        CopyMem (&(Mode->PxeDiscover), &(Token.Packet->Dhcp4), Token.Packet->Length);
        Mode->PxeDiscoverValid = TRUE;

        CopyMem (Mode->PxeReply.Raw, &Response->Dhcp4, Response->Length);
        Mode->PxeReplyReceived = TRUE;
      }
    } else {
      Status = EFI_NOT_FOUND;
    }

    //
    // free the responselist
    //
    gBS->FreePool (Token.ResponseList);
  }
  //
  // Free the dhcp packet
  //
  gBS->FreePool (Token.Packet);

  return Status;
}


/**
  GC_NOTO: Add function description

  @param  Buffer                GC_NOTO: add argument description
  @param  Length                GC_NOTO: add argument description
  @param  OptTag                GC_NOTO: add argument description

  @return GC_NOTO: add return values

**/
EFI_DHCP4_PACKET_OPTION *
PxeBcParseExtendOptions (
  IN UINT8                         *Buffer,
  IN UINT32                        Length,
  IN UINT8                         OptTag
  )
{
  EFI_DHCP4_PACKET_OPTION *Option;
  UINT32                  Offset;

  Option  = (EFI_DHCP4_PACKET_OPTION *) Buffer;
  Offset  = 0;

  while (Offset < Length && Option->OpCode != PXEBC_DHCP4_TAG_EOP) {

    if (Option->OpCode == OptTag) {

      return Option;
    }

    if (Option->OpCode == PXEBC_DHCP4_TAG_PAD) {
      Offset++;
    } else {
      Offset += Option->Length + 2;
    }

    Option = (EFI_DHCP4_PACKET_OPTION *) (Buffer + Offset);
  }

  return NULL;
}


/**
  This function is to parse and check vendor options.

  @param  Dhcp4Option           Pointer to dhcp options
  @param  VendorOption          Pointer to vendor options

  @return TRUE  : Valid vendor options
  @return FALSE : Invalid vendor options

**/
BOOLEAN
PxeBcParseVendorOptions (
  IN EFI_DHCP4_PACKET_OPTION       *Dhcp4Option,
  IN PXEBC_VENDOR_OPTION           *VendorOption
  )
{
  UINT32                  *BitMap;
  UINT8                   VendorOptionLen;
  EFI_DHCP4_PACKET_OPTION *PxeOption;
  UINT8                   Offset;

  BitMap          = VendorOption->BitMap;
  VendorOptionLen = Dhcp4Option->Length;
  PxeOption       = (EFI_DHCP4_PACKET_OPTION *) &Dhcp4Option->Data[0];
  Offset          = 0;

  while ((Offset < VendorOptionLen) && (PxeOption->OpCode != PXEBC_DHCP4_TAG_EOP)) {
    //
    // Parse every Vendor Option and set its BitMap
    //
    switch (PxeOption->OpCode) {

    case PXEBC_VENDOR_TAG_MTFTP_IP:

      CopyMem (&VendorOption->MtftpIp, PxeOption->Data, sizeof (EFI_IPv4_ADDRESS));
      break;

    case PXEBC_VENDOR_TAG_MTFTP_CPORT:

      CopyMem (&VendorOption->MtftpCPort, PxeOption->Data, sizeof (VendorOption->MtftpCPort));
      break;

    case PXEBC_VENDOR_TAG_MTFTP_SPORT:

      CopyMem (&VendorOption->MtftpSPort, PxeOption->Data, sizeof (VendorOption->MtftpSPort));
      break;

    case PXEBC_VENDOR_TAG_MTFTP_TIMEOUT:

      VendorOption->MtftpTimeout = *PxeOption->Data;
      break;

    case PXEBC_VENDOR_TAG_MTFTP_DELAY:

      VendorOption->MtftpDelay = *PxeOption->Data;
      break;

    case PXEBC_VENDOR_TAG_DISCOVER_CTRL:

      VendorOption->DiscoverCtrl = *PxeOption->Data;
      break;

    case PXEBC_VENDOR_TAG_DISCOVER_MCAST:

      CopyMem (&VendorOption->DiscoverMcastIp, PxeOption->Data, sizeof (EFI_IPv4_ADDRESS));
      break;

    case PXEBC_VENDOR_TAG_BOOT_SERVERS:

      VendorOption->BootSvrLen  = PxeOption->Length;
      VendorOption->BootSvr     = (PXEBC_BOOT_SVR_ENTRY *) PxeOption->Data;
      break;

    case PXEBC_VENDOR_TAG_BOOT_MENU:

      VendorOption->BootMenuLen = PxeOption->Length;
      VendorOption->BootMenu    = (PXEBC_BOOT_MENU_ENTRY *) PxeOption->Data;
      break;

    case PXEBC_VENDOR_TAG_MENU_PROMPT:

      VendorOption->MenuPromptLen = PxeOption->Length;
      VendorOption->MenuPrompt    = (PXEBC_MENU_PROMPT *) PxeOption->Data;
      break;

    case PXEBC_VENDOR_TAG_MCAST_ALLOC:

      CopyMem (&VendorOption->McastIpBase, PxeOption->Data, sizeof (EFI_IPv4_ADDRESS));
      CopyMem (&VendorOption->McastIpBlock, PxeOption->Data + 4, sizeof (VendorOption->McastIpBlock));
      CopyMem (&VendorOption->McastIpRange, PxeOption->Data + 6, sizeof (VendorOption->McastIpRange));
      break;

    case PXEBC_VENDOR_TAG_CREDENTIAL_TYPES:

      VendorOption->CredTypeLen = PxeOption->Length;
      VendorOption->CredType    = (UINT32 *) PxeOption->Data;
      break;

    case PXEBC_VENDOR_TAG_BOOT_ITEM:

      CopyMem (&VendorOption->BootSrvType, PxeOption->Data, sizeof (VendorOption->BootSrvType));
      CopyMem (&VendorOption->BootSrvLayer, PxeOption->Data + 2, sizeof (VendorOption->BootSrvLayer));
      break;
    }

    SET_VENDOR_OPTION_BIT_MAP (BitMap, PxeOption->OpCode);

    if (PxeOption->OpCode == PXEBC_DHCP4_TAG_PAD) {
      Offset++;
    } else {
      Offset = (UINT8) (Offset + PxeOption->Length + 2);
    }

    PxeOption = (EFI_DHCP4_PACKET_OPTION *) (Dhcp4Option->Data + Offset);
  }

  //
  // FixMe, return falas if invalid of any vendor option
  //

  return TRUE;
}


/**
  GC_NOTO: Add function description

  @param  Str                   GC_NOTO: add argument description
  @param  Len                   GC_NOTO: add argument description

  @return GC_NOTO: add return values

**/
VOID
PxeBcDisplayBootItem (
  IN UINT8                 *Str,
  IN UINT8                 Len
  )
{
  UINT8 Tmp;

  Len       = (UINT8) MIN (70, Len);
  Tmp       = Str[Len];
  Str[Len]  = 0;
  AsciiPrint ("%a \n", Str);
  Str[Len] = Tmp;
}


/**
  GC_NOTO: Add function description

  @param  Private               GC_NOTO: add argument description

  @retval EFI_SUCCESS           GC_NOTO: Add description for return value
  @retval EFI_TIMEOUT           GC_NOTO: Add description for return value

**/
EFI_STATUS
PxeBcSelectBootPrompt (
  IN PXEBC_PRIVATE_DATA              *Private
  )
{
  PXEBC_CACHED_DHCP4_PACKET  *Packet;
  PXEBC_VENDOR_OPTION       *VendorOpt;
  EFI_EVENT                  TimeoutEvent;
  EFI_EVENT                  DescendEvent;
  EFI_INPUT_KEY              InputKey;
  EFI_STATUS                 Status;
  UINT8                      Timeout;
  UINT8                      *Prompt;
  UINT8                      PromptLen;
  INT32                      SecCol;
  INT32                      SecRow;

  TimeoutEvent  = NULL;
  DescendEvent  = NULL;

  if (Private->PxeBc.Mode->ProxyOfferReceived) {

    Packet  = &Private->ProxyOffer;
  } else {

    Packet  = &Private->Dhcp4Ack;
  }

  if (Packet->OfferType != DHCP4_PACKET_TYPE_PXE10) {
    return EFI_NOT_FOUND;
  }

  VendorOpt = &Packet->PxeVendorOption;

  if (!IS_VALID_BOOT_PROMPT (VendorOpt->BitMap)) {
    return EFI_SUCCESS;
  }

  Timeout   = VendorOpt->MenuPrompt->Timeout;
  Prompt    = VendorOpt->MenuPrompt->Prompt;
  PromptLen = (UINT8) (VendorOpt->MenuPromptLen - 1);

  if (Timeout == 0) {
    return EFI_SUCCESS;
  }

  if (Timeout == 255) {
    return EFI_TIMEOUT;
  }

  Status = gBS->CreateEvent (
                  EVT_TIMER,
                  TPL_CALLBACK,
                  NULL,
                  NULL,
                  &TimeoutEvent
                  );

  if (EFI_ERROR (Status)) {
    return Status;
  }

  Status = gBS->SetTimer (
                  TimeoutEvent,
                  TimerRelative,
                  Timeout * TICKS_PER_SECOND
                  );

  if (EFI_ERROR (Status)) {
    goto ON_EXIT;
  }

  Status = gBS->CreateEvent (
                  EVT_TIMER,
                  TPL_CALLBACK,
                  NULL,
                  NULL,
                  &DescendEvent
                  );

  if (EFI_ERROR (Status)) {
    goto ON_EXIT;
  }

  Status = gBS->SetTimer (
                  DescendEvent,
                  TimerPeriodic,
                  TICKS_PER_SECOND
                  );

  if (EFI_ERROR (Status)) {
    goto ON_EXIT;
  }

  SecCol = gST->ConOut->Mode->CursorColumn;
  SecRow = gST->ConOut->Mode->CursorRow;

  PxeBcDisplayBootItem (Prompt, PromptLen);

  gST->ConOut->SetCursorPosition (gST->ConOut, SecCol + PromptLen, SecRow);
  AsciiPrint ("(%d) ", Timeout--);

  while (EFI_ERROR (gBS->CheckEvent (TimeoutEvent))) {

    if (!EFI_ERROR (gBS->CheckEvent (DescendEvent))) {
      gST->ConOut->SetCursorPosition (gST->ConOut, SecCol + PromptLen, SecRow);
      AsciiPrint ("(%d) ", Timeout--);
    }

    if (gST->ConIn->ReadKeyStroke (gST->ConIn, &InputKey) == EFI_NOT_READY) {

      gBS->Stall (10 * TICKS_PER_MS);
      continue;
    }

    if (InputKey.ScanCode == 0) {

      switch (InputKey.UnicodeChar) {
      case CTRL ('c'):
        Status = EFI_ABORTED;
        break;

      case CTRL ('m'):
      case 'm':
      case 'M':
        Status = EFI_TIMEOUT;
        break;

      default:
        continue;
      }
    } else {

      switch (InputKey.ScanCode) {
      case SCAN_F8:
        Status = EFI_TIMEOUT;
        break;

      case SCAN_ESC:
        Status = EFI_ABORTED;
        break;

      default:
        continue;
      }
    }

    break;
  }

  gST->ConOut->SetCursorPosition (gST->ConOut, 0 , SecRow + 1);

ON_EXIT:

  if (DescendEvent != NULL) {
    gBS->CloseEvent (DescendEvent);
  }

  if (TimeoutEvent != NULL) {
    gBS->CloseEvent (TimeoutEvent);
  }

  return Status;
}


/**
  GC_NOTO: Add function description

  @param  Private               GC_NOTO: add argument description
  @param  Type                  GC_NOTO: add argument description

  @retval EFI_ABORTED           GC_NOTO: Add description for return value
  @retval EFI_SUCCESS           GC_NOTO: Add description for return value

**/
EFI_STATUS
PxeBcSelectBootMenu (
  IN  PXEBC_PRIVATE_DATA              *Private,
  OUT UINT16                          *Type,
  IN  BOOLEAN                         UseDefaultItem
  )
{
  PXEBC_CACHED_DHCP4_PACKET  *Packet;
  PXEBC_VENDOR_OPTION       *VendorOpt;
  EFI_INPUT_KEY              InputKey;
  UINT8                      MenuSize;
  UINT8                      MenuNum;
  INT32                      TopRow;
  UINT16                     Select;
  UINT16                     LastSelect;
  UINT8                      Index;
  BOOLEAN                    Finish;
  CHAR8                      Blank[70];
  PXEBC_BOOT_MENU_ENTRY      *MenuItem;
  PXEBC_BOOT_MENU_ENTRY      *MenuArray[PXEBC_MAX_MENU_NUM];

  Finish  = FALSE;
  Select  = 1;
  Index   = 0;
  *Type   = 0;

  if (Private->PxeBc.Mode->ProxyOfferReceived) {

    Packet  = &Private->ProxyOffer;
  } else {

    Packet  = &Private->Dhcp4Ack;
  }

  ASSERT (Packet->OfferType == DHCP4_PACKET_TYPE_PXE10);

  VendorOpt = &Packet->PxeVendorOption;

  if (!IS_VALID_BOOT_MENU (VendorOpt->BitMap)) {
    return EFI_SUCCESS;
  }

  SetMem (Blank, sizeof(Blank), ' ');

  MenuSize  = VendorOpt->BootMenuLen;
  MenuItem  = VendorOpt->BootMenu;

  while (MenuSize > 0) {
    MenuArray[Index]  = MenuItem;
    MenuSize          = (UINT8) (MenuSize - (MenuItem->DescLen + 3));
    MenuItem          = (PXEBC_BOOT_MENU_ENTRY *) ((UINT8 *) MenuItem + MenuItem->DescLen + 3);
    Index++;
  }

  if (UseDefaultItem) {
    *Type = NTOHS (MenuArray[0]->Type);
    return EFI_SUCCESS;
  }

  MenuNum = Index;

  for (Index = 0; Index < MenuNum; Index++) {
    PxeBcDisplayBootItem (MenuArray[Index]->DescStr, MenuArray[Index]->DescLen);
  }

  TopRow  = gST->ConOut->Mode->CursorRow - MenuNum;

  do {
    //
    // highlight selected row
    //
    gST->ConOut->SetAttribute (gST->ConOut, EFI_TEXT_ATTR (EFI_BLACK, EFI_LIGHTGRAY));
    gST->ConOut->SetCursorPosition (gST->ConOut, 0, TopRow + Select);
    Blank[MenuArray[Select]->DescLen] = 0;
    AsciiPrint ("%a\r", Blank);
    PxeBcDisplayBootItem (MenuArray[Select]->DescStr, MenuArray[Select]->DescLen);
    gST->ConOut->SetCursorPosition (gST->ConOut, 0, TopRow + MenuNum);
    LastSelect = Select;

    while (gST->ConIn->ReadKeyStroke (gST->ConIn, &InputKey) == EFI_NOT_READY) {
      gBS->Stall (10 * TICKS_PER_MS);
    }

    if (!InputKey.ScanCode) {
      switch (InputKey.UnicodeChar) {
      case CTRL ('c'):
        InputKey.ScanCode = SCAN_ESC;
        break;

      case CTRL ('j'):  /* linefeed */
      case CTRL ('m'):  /* return */
        Finish = TRUE;
        break;

      case CTRL ('i'):  /* tab */
      case ' ':
      case 'd':
      case 'D':
        InputKey.ScanCode = SCAN_DOWN;
        break;

      case CTRL ('h'):  /* backspace */
      case 'u':
      case 'U':
        InputKey.ScanCode = SCAN_UP;
        break;

      default:
        InputKey.ScanCode = 0;
      }
    }

    switch (InputKey.ScanCode) {
    case SCAN_LEFT:
    case SCAN_UP:
      if (Select) {
        --Select;
      }

      break;

    case SCAN_DOWN:
    case SCAN_RIGHT:
      if (++Select == MenuNum) {
        --Select;
      }

      break;

    case SCAN_PAGE_UP:
    case SCAN_HOME:
      Select = 0;
      break;

    case SCAN_PAGE_DOWN:
    case SCAN_END:
      Select = (UINT16) (MenuNum - 1);
      break;

    case SCAN_ESC:
      return EFI_ABORTED;
    }

    /* unhighlight last selected row */
    gST->ConOut->SetAttribute (gST->ConOut, EFI_TEXT_ATTR (EFI_LIGHTGRAY, EFI_BLACK));
    gST->ConOut->SetCursorPosition (gST->ConOut, 0, TopRow + LastSelect);
    Blank[MenuArray[LastSelect]->DescLen] = 0;
    AsciiPrint ("%a\r", Blank);
    PxeBcDisplayBootItem (MenuArray[LastSelect]->DescStr, MenuArray[LastSelect]->DescLen);
    gST->ConOut->SetCursorPosition (gST->ConOut, 0, TopRow + MenuNum);
  } while (!Finish);

  //
  // Swap the byte order
  //
  *Type = NTOHS (MenuArray[Select]->Type);

  return EFI_SUCCESS;
}