/** @file
  Functions implementation related with DHCPv6 for HTTP boot driver.

Copyright (c) 2015 - 2018, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent

**/

#include "HttpBootDxe.h"

/**
  Build the options buffer for the DHCPv6 request packet.

  @param[in]  Private             The pointer to HTTP BOOT driver private data.
  @param[out] OptList             The pointer to the option pointer array.
  @param[in]  Buffer              The pointer to the buffer to contain the option list.

  @return     Index               The count of the built-in options.

**/
UINT32
HttpBootBuildDhcp6Options (
  IN  HTTP_BOOT_PRIVATE_DATA   *Private,
  OUT EFI_DHCP6_PACKET_OPTION  **OptList,
  IN  UINT8                    *Buffer
  )
{
  HTTP_BOOT_DHCP6_OPTION_ENTRY  OptEnt;
  UINT16                        Value;
  UINT32                        Index;

  Index      = 0;
  OptList[0] = (EFI_DHCP6_PACKET_OPTION *)Buffer;

  //
  // Append client option request option
  //
  OptList[Index]->OpCode = HTONS (DHCP6_OPT_ORO);
  OptList[Index]->OpLen  = HTONS (8);
  OptEnt.Oro             = (HTTP_BOOT_DHCP6_OPTION_ORO *)OptList[Index]->Data;
  OptEnt.Oro->OpCode[0]  = HTONS (DHCP6_OPT_BOOT_FILE_URL);
  OptEnt.Oro->OpCode[1]  = HTONS (DHCP6_OPT_BOOT_FILE_PARAM);
  OptEnt.Oro->OpCode[2]  = HTONS (DHCP6_OPT_DNS_SERVERS);
  OptEnt.Oro->OpCode[3]  = HTONS (DHCP6_OPT_VENDOR_CLASS);
  Index++;
  OptList[Index] = GET_NEXT_DHCP6_OPTION (OptList[Index - 1]);

  //
  // Append client network device interface option
  //
  OptList[Index]->OpCode = HTONS (DHCP6_OPT_UNDI);
  OptList[Index]->OpLen  = HTONS ((UINT16)3);
  OptEnt.Undi            = (HTTP_BOOT_DHCP6_OPTION_UNDI *)OptList[Index]->Data;

  if (Private->Nii != NULL) {
    OptEnt.Undi->Type     = Private->Nii->Type;
    OptEnt.Undi->MajorVer = Private->Nii->MajorVer;
    OptEnt.Undi->MinorVer = Private->Nii->MinorVer;
  } else {
    OptEnt.Undi->Type     = DEFAULT_UNDI_TYPE;
    OptEnt.Undi->MajorVer = DEFAULT_UNDI_MAJOR;
    OptEnt.Undi->MinorVer = DEFAULT_UNDI_MINOR;
  }

  Index++;
  OptList[Index] = GET_NEXT_DHCP6_OPTION (OptList[Index - 1]);

  //
  // Append client system architecture option
  //
  OptList[Index]->OpCode = HTONS (DHCP6_OPT_ARCH);
  OptList[Index]->OpLen  = HTONS ((UINT16)sizeof (HTTP_BOOT_DHCP6_OPTION_ARCH));
  OptEnt.Arch            = (HTTP_BOOT_DHCP6_OPTION_ARCH *)OptList[Index]->Data;
  Value                  = HTONS (EFI_HTTP_BOOT_CLIENT_SYSTEM_ARCHITECTURE);
  CopyMem (&OptEnt.Arch->Type, &Value, sizeof (UINT16));
  Index++;
  OptList[Index] = GET_NEXT_DHCP6_OPTION (OptList[Index - 1]);

  //
  // Append vendor class identify option.
  //
  OptList[Index]->OpCode       = HTONS (DHCP6_OPT_VENDOR_CLASS);
  OptList[Index]->OpLen        = HTONS ((UINT16)sizeof (HTTP_BOOT_DHCP6_OPTION_VENDOR_CLASS));
  OptEnt.VendorClass           = (HTTP_BOOT_DHCP6_OPTION_VENDOR_CLASS *)OptList[Index]->Data;
  OptEnt.VendorClass->Vendor   = HTONL (HTTP_BOOT_DHCP6_ENTERPRISE_NUM);
  OptEnt.VendorClass->ClassLen = HTONS ((UINT16)sizeof (HTTP_BOOT_CLASS_ID));
  CopyMem (
    &OptEnt.VendorClass->ClassId,
    DEFAULT_CLASS_ID_DATA,
    sizeof (HTTP_BOOT_CLASS_ID)
    );
  HttpBootUintnToAscDecWithFormat (
    EFI_HTTP_BOOT_CLIENT_SYSTEM_ARCHITECTURE,
    OptEnt.VendorClass->ClassId.ArchitectureType,
    sizeof (OptEnt.VendorClass->ClassId.ArchitectureType)
    );

  if (Private->Nii != NULL) {
    CopyMem (
      OptEnt.VendorClass->ClassId.InterfaceName,
      Private->Nii->StringId,
      sizeof (OptEnt.VendorClass->ClassId.InterfaceName)
      );
    HttpBootUintnToAscDecWithFormat (
      Private->Nii->MajorVer,
      OptEnt.VendorClass->ClassId.UndiMajor,
      sizeof (OptEnt.VendorClass->ClassId.UndiMajor)
      );
    HttpBootUintnToAscDecWithFormat (
      Private->Nii->MinorVer,
      OptEnt.VendorClass->ClassId.UndiMinor,
      sizeof (OptEnt.VendorClass->ClassId.UndiMinor)
      );
  }

  Index++;

  return Index;
}

/**
  Parse out a DHCPv6 option by OptTag, and find the position in buffer.

  @param[in]  Buffer        The pointer to the option buffer.
  @param[in]  Length        Length of the option buffer.
  @param[in]  OptTag        The required option tag.

  @retval     NULL          Failed to parse the required option.
  @retval     Others        The position of the required option in buffer.

**/
EFI_DHCP6_PACKET_OPTION *
HttpBootParseDhcp6Options (
  IN UINT8   *Buffer,
  IN UINT32  Length,
  IN UINT16  OptTag
  )
{
  EFI_DHCP6_PACKET_OPTION  *Option;
  UINT32                   Offset;

  Option = (EFI_DHCP6_PACKET_OPTION *)Buffer;
  Offset = 0;

  //
  // OpLen and OpCode here are both stored in network order.
  //
  while (Offset < Length) {
    if (NTOHS (Option->OpCode) == OptTag) {
      return Option;
    }

    Offset += (NTOHS (Option->OpLen) + 4);
    Option  = (EFI_DHCP6_PACKET_OPTION *)(Buffer + Offset);
  }

  return NULL;
}

/**
  Parse the cached DHCPv6 packet, including all the options.

  @param[in]  Cache6           The pointer to a cached DHCPv6 packet.

  @retval     EFI_SUCCESS      Parsed the DHCPv6 packet successfully.
  @retval     EFI_DEVICE_ERROR Failed to parse and invalid the packet.

**/
EFI_STATUS
HttpBootParseDhcp6Packet (
  IN  HTTP_BOOT_DHCP6_PACKET_CACHE  *Cache6
  )
{
  EFI_DHCP6_PACKET         *Offer;
  EFI_DHCP6_PACKET_OPTION  **Options;
  EFI_DHCP6_PACKET_OPTION  *Option;
  HTTP_BOOT_OFFER_TYPE     OfferType;
  EFI_IPv6_ADDRESS         IpAddr;
  BOOLEAN                  IsProxyOffer;
  BOOLEAN                  IsHttpOffer;
  BOOLEAN                  IsDnsOffer;
  BOOLEAN                  IpExpressedUri;
  EFI_STATUS               Status;
  UINT32                   Offset;
  UINT32                   Length;

  IsDnsOffer     = FALSE;
  IpExpressedUri = FALSE;
  IsProxyOffer   = TRUE;
  IsHttpOffer    = FALSE;
  Offer          = &Cache6->Packet.Offer;
  Options        = Cache6->OptList;

  ZeroMem (Cache6->OptList, sizeof (Cache6->OptList));

  Option = (EFI_DHCP6_PACKET_OPTION *)(Offer->Dhcp6.Option);
  Offset = 0;
  Length = GET_DHCP6_OPTION_SIZE (Offer);

  //
  // OpLen and OpCode here are both stored in network order, since they are from original packet.
  //
  while (Offset < Length) {
    if (NTOHS (Option->OpCode) == DHCP6_OPT_IA_NA) {
      Options[HTTP_BOOT_DHCP6_IDX_IA_NA] = Option;
    } else if (NTOHS (Option->OpCode) == DHCP6_OPT_BOOT_FILE_URL) {
      //
      // The server sends this option to inform the client about an URL to a boot file.
      //
      Options[HTTP_BOOT_DHCP6_IDX_BOOT_FILE_URL] = Option;
    } else if (NTOHS (Option->OpCode) == DHCP6_OPT_BOOT_FILE_PARAM) {
      Options[HTTP_BOOT_DHCP6_IDX_BOOT_FILE_PARAM] = Option;
    } else if (NTOHS (Option->OpCode) == DHCP6_OPT_VENDOR_CLASS) {
      Options[HTTP_BOOT_DHCP6_IDX_VENDOR_CLASS] = Option;
    } else if (NTOHS (Option->OpCode) == DHCP6_OPT_DNS_SERVERS) {
      Options[HTTP_BOOT_DHCP6_IDX_DNS_SERVER] = Option;
    }

    Offset += (NTOHS (Option->OpLen) + 4);
    Option  = (EFI_DHCP6_PACKET_OPTION *)(Offer->Dhcp6.Option + Offset);
  }

  //
  // The offer with assigned client address is NOT a proxy offer.
  // An ia_na option, embedded with valid ia_addr option and a status_code of success.
  //
  Option = Options[HTTP_BOOT_DHCP6_IDX_IA_NA];
  if (Option != NULL) {
    Option = HttpBootParseDhcp6Options (
               Option->Data + 12,
               NTOHS (Option->OpLen),
               DHCP6_OPT_STATUS_CODE
               );
    if (((Option != NULL) && (Option->Data[0] == 0)) || (Option == NULL)) {
      IsProxyOffer = FALSE;
    }
  }

  //
  // The offer with "HTTPClient" is a Http offer.
  //
  Option = Options[HTTP_BOOT_DHCP6_IDX_VENDOR_CLASS];

  if ((Option != NULL) &&
      (NTOHS (Option->OpLen) >= 16) &&
      (CompareMem ((Option->Data + 6), DEFAULT_CLASS_ID_DATA, 10) == 0))
  {
    IsHttpOffer = TRUE;
  }

  //
  // The offer with Domain Server is a DNS offer.
  //
  Option = Options[HTTP_BOOT_DHCP6_IDX_DNS_SERVER];
  if (Option != NULL) {
    IsDnsOffer = TRUE;
  }

  //
  // Http offer must have a boot URI.
  //
  if (IsHttpOffer && (Options[HTTP_BOOT_DHCP6_IDX_BOOT_FILE_URL] == NULL)) {
    return EFI_DEVICE_ERROR;
  }

  //
  // Try to retrieve the IP of HTTP server from URI.
  //
  if (IsHttpOffer) {
    Status = HttpParseUrl (
               (CHAR8 *)Options[HTTP_BOOT_DHCP6_IDX_BOOT_FILE_URL]->Data,
               (UINT32)AsciiStrLen ((CHAR8 *)Options[HTTP_BOOT_DHCP6_IDX_BOOT_FILE_URL]->Data),
               FALSE,
               &Cache6->UriParser
               );
    if (EFI_ERROR (Status)) {
      return EFI_DEVICE_ERROR;
    }

    Status = HttpUrlGetIp6 (
               (CHAR8 *)Options[HTTP_BOOT_DHCP6_IDX_BOOT_FILE_URL]->Data,
               Cache6->UriParser,
               &IpAddr
               );
    IpExpressedUri = !EFI_ERROR (Status);
  }

  //
  // Determine offer type of the DHCPv6 packet.
  //
  if (IsHttpOffer) {
    if (IpExpressedUri) {
      if (IsProxyOffer) {
        OfferType = HttpOfferTypeProxyIpUri;
      } else {
        OfferType = IsDnsOffer ? HttpOfferTypeDhcpIpUriDns : HttpOfferTypeDhcpIpUri;
      }
    } else {
      if (!IsProxyOffer) {
        OfferType = IsDnsOffer ? HttpOfferTypeDhcpNameUriDns : HttpOfferTypeDhcpNameUri;
      } else {
        OfferType = HttpOfferTypeProxyNameUri;
      }
    }
  } else {
    if (!IsProxyOffer) {
      OfferType = IsDnsOffer ? HttpOfferTypeDhcpDns : HttpOfferTypeDhcpOnly;
    } else {
      return EFI_DEVICE_ERROR;
    }
  }

  Cache6->OfferType = OfferType;
  return EFI_SUCCESS;
}

/**
  Cache the DHCPv6 packet.

  @param[in]  Dst          The pointer to the cache buffer for DHCPv6 packet.
  @param[in]  Src          The pointer to the DHCPv6 packet to be cached.

  @retval     EFI_SUCCESS                Packet is copied.
  @retval     EFI_BUFFER_TOO_SMALL       Cache buffer is not big enough to hold the packet.

**/
EFI_STATUS
HttpBootCacheDhcp6Packet (
  IN EFI_DHCP6_PACKET  *Dst,
  IN EFI_DHCP6_PACKET  *Src
  )
{
  if (Dst->Size < Src->Length) {
    return EFI_BUFFER_TOO_SMALL;
  }

  CopyMem (&Dst->Dhcp6, &Src->Dhcp6, Src->Length);
  Dst->Length = Src->Length;

  return EFI_SUCCESS;
}

/**
  Cache all the received DHCPv6 offers, and set OfferIndex and OfferCount.

  @param[in]  Private               The pointer to HTTP_BOOT_PRIVATE_DATA.
  @param[in]  RcvdOffer             The pointer to the received offer packet.

  @retval     EFI_SUCCESS      Cache and parse the packet successfully.
  @retval     Others           Operation failed.

**/
EFI_STATUS
HttpBootCacheDhcp6Offer (
  IN HTTP_BOOT_PRIVATE_DATA  *Private,
  IN EFI_DHCP6_PACKET        *RcvdOffer
  )
{
  HTTP_BOOT_DHCP6_PACKET_CACHE  *Cache6;
  EFI_DHCP6_PACKET              *Offer;
  HTTP_BOOT_OFFER_TYPE          OfferType;
  EFI_STATUS                    Status;

  Cache6 = &Private->OfferBuffer[Private->OfferNum].Dhcp6;
  Offer  = &Cache6->Packet.Offer;

  //
  // Cache the content of DHCPv6 packet firstly.
  //
  Status = HttpBootCacheDhcp6Packet (Offer, RcvdOffer);
  if (EFI_ERROR (Status)) {
    return Status;
  }

  //
  // Validate the DHCPv6 packet, and parse the options and offer type.
  //
  if (EFI_ERROR (HttpBootParseDhcp6Packet (Cache6))) {
    return EFI_ABORTED;
  }

  //
  // Determine whether cache the current offer by type, and record OfferIndex and OfferCount.
  //
  OfferType = Cache6->OfferType;
  ASSERT (OfferType < HttpOfferTypeMax);
  ASSERT (Private->OfferCount[OfferType] < HTTP_BOOT_OFFER_MAX_NUM);
  Private->OfferIndex[OfferType][Private->OfferCount[OfferType]] = Private->OfferNum;
  Private->OfferCount[OfferType]++;
  Private->OfferNum++;

  return EFI_SUCCESS;
}

/**
  EFI_DHCP6_CALLBACK is provided by the consumer of the EFI DHCPv6 Protocol driver
  to intercept events that occurred in the configuration process.

  @param[in]  This              The pointer to the EFI DHCPv6 Protocol.
  @param[in]  Context           The pointer to the context set by EFI_DHCP6_PROTOCOL.Configure().
  @param[in]  CurrentState      The current operational state of the EFI DHCPv Protocol driver.
  @param[in]  Dhcp6Event        The event that occurs in the current state, which usually means a
                                state transition.
  @param[in]  Packet            The DHCPv6 packet that is going to be sent or was already received.
  @param[out] NewPacket         The packet that is used to replace the Packet above.

  @retval EFI_SUCCESS           Told the EFI DHCPv6 Protocol driver to continue the DHCP process.
  @retval EFI_NOT_READY         Only used in the Dhcp6Selecting state. The EFI DHCPv6 Protocol
                                driver will continue to wait for more packets.
  @retval EFI_ABORTED           Told the EFI DHCPv6 Protocol driver to abort the current process.
  @retval EFI_OUT_OF_RESOURCES  There are not enough resources.

**/
EFI_STATUS
EFIAPI
HttpBootDhcp6CallBack (
  IN  EFI_DHCP6_PROTOCOL  *This,
  IN  VOID                *Context,
  IN  EFI_DHCP6_STATE     CurrentState,
  IN  EFI_DHCP6_EVENT     Dhcp6Event,
  IN  EFI_DHCP6_PACKET    *Packet,
  OUT EFI_DHCP6_PACKET    **NewPacket     OPTIONAL
  )
{
  HTTP_BOOT_PRIVATE_DATA  *Private;
  EFI_DHCP6_PACKET        *SelectAd;
  EFI_STATUS              Status;
  BOOLEAN                 Received;

  if ((Dhcp6Event != Dhcp6SendSolicit) &&
      (Dhcp6Event != Dhcp6RcvdAdvertise) &&
      (Dhcp6Event != Dhcp6SendRequest) &&
      (Dhcp6Event != Dhcp6RcvdReply) &&
      (Dhcp6Event != Dhcp6SelectAdvertise))
  {
    return EFI_SUCCESS;
  }

  ASSERT (Packet != NULL);

  Private = (HTTP_BOOT_PRIVATE_DATA *)Context;
  Status  = EFI_SUCCESS;
  if ((Private->HttpBootCallback != NULL) && (Dhcp6Event != Dhcp6SelectAdvertise)) {
    Received = (BOOLEAN)(Dhcp6Event == Dhcp6RcvdAdvertise || Dhcp6Event == Dhcp6RcvdReply);
    Status   = Private->HttpBootCallback->Callback (
                                            Private->HttpBootCallback,
                                            HttpBootDhcp6,
                                            Received,
                                            Packet->Length,
                                            &Packet->Dhcp6
                                            );
    if (EFI_ERROR (Status)) {
      return EFI_ABORTED;
    }
  }

  switch (Dhcp6Event) {
    case Dhcp6RcvdAdvertise:
      Status = EFI_NOT_READY;
      if (Packet->Length > HTTP_BOOT_DHCP6_PACKET_MAX_SIZE) {
        //
        // Ignore the incoming packets which exceed the maximum length.
        //
        break;
      }

      if (Private->OfferNum < HTTP_BOOT_OFFER_MAX_NUM) {
        //
        // Cache the dhcp offers to OfferBuffer[] for select later, and record
        // the OfferIndex and OfferCount.
        // If error happens, just ignore this packet and continue to wait more offer.
        //
        HttpBootCacheDhcp6Offer (Private, Packet);
      }

      break;

    case Dhcp6SelectAdvertise:
      //
      // Select offer by the default policy or by order, and record the SelectIndex
      // and SelectProxyType.
      //
      HttpBootSelectDhcpOffer (Private);

      if (Private->SelectIndex == 0) {
        Status = EFI_ABORTED;
      } else {
        ASSERT (NewPacket != NULL);
        SelectAd   = &Private->OfferBuffer[Private->SelectIndex - 1].Dhcp6.Packet.Offer;
        *NewPacket = AllocateZeroPool (SelectAd->Size);
        if (*NewPacket == NULL) {
          return EFI_OUT_OF_RESOURCES;
        }

        CopyMem (*NewPacket, SelectAd, SelectAd->Size);
      }

      break;

    default:
      break;
  }

  return Status;
}

/**
  Check whether IP driver could route the message which will be sent to ServerIp address.

  This function will check the IP6 route table every 1 seconds until specified timeout is expired, if a valid
  route is found in IP6 route table, the address will be filed in GatewayAddr and return.

  @param[in]  Private             The pointer to HTTP_BOOT_PRIVATE_DATA.
  @param[in]  TimeOutInSecond     Timeout value in seconds.
  @param[out] GatewayAddr         Pointer to store the gateway IP address.

  @retval     EFI_SUCCESS         Found a valid gateway address successfully.
  @retval     EFI_TIMEOUT         The operation is time out.
  @retval     Other               Unexpected error happened.

**/
EFI_STATUS
HttpBootCheckRouteTable (
  IN  HTTP_BOOT_PRIVATE_DATA  *Private,
  IN  UINTN                   TimeOutInSecond,
  OUT EFI_IPv6_ADDRESS        *GatewayAddr
  )
{
  EFI_STATUS         Status;
  EFI_IP6_PROTOCOL   *Ip6;
  EFI_IP6_MODE_DATA  Ip6ModeData;
  UINTN              Index;
  EFI_EVENT          TimeOutEvt;
  UINTN              RetryCount;
  BOOLEAN            GatewayIsFound;

  ASSERT (GatewayAddr != NULL);
  ASSERT (Private != NULL);

  Ip6            = Private->Ip6;
  GatewayIsFound = FALSE;
  RetryCount     = 0;
  TimeOutEvt     = NULL;
  Status         = EFI_SUCCESS;
  ZeroMem (GatewayAddr, sizeof (EFI_IPv6_ADDRESS));

  while (TRUE) {
    Status = Ip6->GetModeData (Ip6, &Ip6ModeData, NULL, NULL);
    if (EFI_ERROR (Status)) {
      goto ON_EXIT;
    }

    //
    // Find out the gateway address which can route the message which send to ServerIp.
    //
    for (Index = 0; Index < Ip6ModeData.RouteCount; Index++) {
      if (NetIp6IsNetEqual (&Private->ServerIp.v6, &Ip6ModeData.RouteTable[Index].Destination, Ip6ModeData.RouteTable[Index].PrefixLength)) {
        IP6_COPY_ADDRESS (GatewayAddr, &Ip6ModeData.RouteTable[Index].Gateway);
        GatewayIsFound = TRUE;
        break;
      }
    }

    if (Ip6ModeData.AddressList != NULL) {
      FreePool (Ip6ModeData.AddressList);
    }

    if (Ip6ModeData.GroupTable != NULL) {
      FreePool (Ip6ModeData.GroupTable);
    }

    if (Ip6ModeData.RouteTable != NULL) {
      FreePool (Ip6ModeData.RouteTable);
    }

    if (Ip6ModeData.NeighborCache != NULL) {
      FreePool (Ip6ModeData.NeighborCache);
    }

    if (Ip6ModeData.PrefixTable != NULL) {
      FreePool (Ip6ModeData.PrefixTable);
    }

    if (Ip6ModeData.IcmpTypeList != NULL) {
      FreePool (Ip6ModeData.IcmpTypeList);
    }

    if (GatewayIsFound || (RetryCount == TimeOutInSecond)) {
      break;
    }

    RetryCount++;

    //
    // Delay 1 second then recheck it again.
    //
    if (TimeOutEvt == NULL) {
      Status = gBS->CreateEvent (
                      EVT_TIMER,
                      TPL_CALLBACK,
                      NULL,
                      NULL,
                      &TimeOutEvt
                      );
      if (EFI_ERROR (Status)) {
        goto ON_EXIT;
      }
    }

    Status = gBS->SetTimer (TimeOutEvt, TimerRelative, TICKS_PER_SECOND);
    if (EFI_ERROR (Status)) {
      goto ON_EXIT;
    }

    while (EFI_ERROR (gBS->CheckEvent (TimeOutEvt))) {
      Ip6->Poll (Ip6);
    }
  }

ON_EXIT:
  if (TimeOutEvt != NULL) {
    gBS->CloseEvent (TimeOutEvt);
  }

  if (GatewayIsFound) {
    Status = EFI_SUCCESS;
  } else if (RetryCount == TimeOutInSecond) {
    Status = EFI_TIMEOUT;
  }

  return Status;
}

/**
  Set the IP6 policy to Automatic.

  @param[in]  Private             The pointer to HTTP_BOOT_PRIVATE_DATA.

  @retval     EFI_SUCCESS         Switch the IP policy successfully.
  @retval     Others              Unexpected error happened.

**/
EFI_STATUS
HttpBootSetIp6Policy (
  IN HTTP_BOOT_PRIVATE_DATA  *Private
  )
{
  EFI_IP6_CONFIG_POLICY    Policy;
  EFI_IP6_CONFIG_PROTOCOL  *Ip6Config;
  EFI_STATUS               Status;
  UINTN                    DataSize;

  Ip6Config = Private->Ip6Config;
  DataSize  = sizeof (EFI_IP6_CONFIG_POLICY);

  //
  // Get and store the current policy of IP6 driver.
  //
  Status = Ip6Config->GetData (
                        Ip6Config,
                        Ip6ConfigDataTypePolicy,
                        &DataSize,
                        &Policy
                        );
  if (EFI_ERROR (Status)) {
    return Status;
  }

  if (Policy == Ip6ConfigPolicyManual) {
    Policy = Ip6ConfigPolicyAutomatic;
    Status = Ip6Config->SetData (
                          Ip6Config,
                          Ip6ConfigDataTypePolicy,
                          sizeof (EFI_IP6_CONFIG_POLICY),
                          &Policy
                          );
    if (EFI_ERROR (Status)) {
      return Status;
    }
  }

  return EFI_SUCCESS;
}

/**
  This function will register the default DNS addresses to the network device.

  @param[in]  Private             The pointer to HTTP_BOOT_PRIVATE_DATA.
  @param[in]  DataLength          Size of the buffer pointed to by DnsServerData in bytes.
  @param[in]  DnsServerData       Point a list of DNS server address in an array
                                  of EFI_IPv6_ADDRESS instances.

  @retval     EFI_SUCCESS         The DNS configuration has been configured successfully.
  @retval     Others              Failed to configure the address.

**/
EFI_STATUS
HttpBootSetIp6Dns (
  IN HTTP_BOOT_PRIVATE_DATA  *Private,
  IN UINTN                   DataLength,
  IN VOID                    *DnsServerData
  )
{
  EFI_IP6_CONFIG_PROTOCOL  *Ip6Config;

  ASSERT (Private->UsingIpv6);

  Ip6Config = Private->Ip6Config;

  return Ip6Config->SetData (
                      Ip6Config,
                      Ip6ConfigDataTypeDnsServer,
                      DataLength,
                      DnsServerData
                      );
}

/**
  This function will register the IPv6 gateway address to the network device.

  @param[in]  Private             The pointer to HTTP_BOOT_PRIVATE_DATA.

  @retval     EFI_SUCCESS         The new IP configuration has been configured successfully.
  @retval     Others              Failed to configure the address.

**/
EFI_STATUS
HttpBootSetIp6Gateway (
  IN HTTP_BOOT_PRIVATE_DATA  *Private
  )
{
  EFI_IP6_CONFIG_PROTOCOL  *Ip6Config;
  EFI_STATUS               Status;

  ASSERT (Private->UsingIpv6);
  Ip6Config = Private->Ip6Config;

  //
  // Set the default gateway address.
  //
  if (!Private->NoGateway && !NetIp6IsUnspecifiedAddr (&Private->GatewayIp.v6)) {
    Status = Ip6Config->SetData (
                          Ip6Config,
                          Ip6ConfigDataTypeGateway,
                          sizeof (EFI_IPv6_ADDRESS),
                          &Private->GatewayIp.v6
                          );
    if (EFI_ERROR (Status)) {
      return Status;
    }
  }

  return EFI_SUCCESS;
}

/**
  This function will register the station IP address.

  @param[in]  Private             The pointer to HTTP_BOOT_PRIVATE_DATA.

  @retval     EFI_SUCCESS         The new IP address has been configured successfully.
  @retval     Others              Failed to configure the address.

**/
EFI_STATUS
HttpBootSetIp6Address (
  IN HTTP_BOOT_PRIVATE_DATA  *Private
  )
{
  EFI_STATUS                     Status;
  EFI_IP6_PROTOCOL               *Ip6;
  EFI_IP6_CONFIG_PROTOCOL        *Ip6Cfg;
  EFI_IP6_CONFIG_POLICY          Policy;
  EFI_IP6_CONFIG_MANUAL_ADDRESS  CfgAddr;
  EFI_IPv6_ADDRESS               *Ip6Addr;
  EFI_IPv6_ADDRESS               GatewayAddr;
  EFI_IP6_CONFIG_DATA            Ip6CfgData;
  EFI_EVENT                      MappedEvt;
  UINTN                          DataSize;
  BOOLEAN                        IsAddressOk;
  UINTN                          Index;

  ASSERT (Private->UsingIpv6);

  MappedEvt   = NULL;
  IsAddressOk = FALSE;
  Ip6Addr     = NULL;
  Ip6Cfg      = Private->Ip6Config;
  Ip6         = Private->Ip6;

  ZeroMem (&CfgAddr, sizeof (EFI_IP6_CONFIG_MANUAL_ADDRESS));
  CopyMem (&CfgAddr, &Private->StationIp.v6, sizeof (EFI_IPv6_ADDRESS));
  ZeroMem (&Ip6CfgData, sizeof (EFI_IP6_CONFIG_DATA));

  Ip6CfgData.AcceptIcmpErrors = TRUE;
  Ip6CfgData.DefaultProtocol  = IP6_ICMP;
  Ip6CfgData.HopLimit         = HTTP_BOOT_DEFAULT_HOPLIMIT;
  Ip6CfgData.ReceiveTimeout   = HTTP_BOOT_DEFAULT_LIFETIME;
  Ip6CfgData.TransmitTimeout  = HTTP_BOOT_DEFAULT_LIFETIME;

  Status = Ip6->Configure (Ip6, &Ip6CfgData);
  if (EFI_ERROR (Status)) {
    goto ON_EXIT;
  }

  //
  // Retrieve the gateway address from IP6 route table.
  //
  Status = HttpBootCheckRouteTable (Private, HTTP_BOOT_IP6_ROUTE_TABLE_TIMEOUT, &GatewayAddr);
  if (EFI_ERROR (Status)) {
    Private->NoGateway = TRUE;
  } else {
    IP6_COPY_ADDRESS (&Private->GatewayIp.v6, &GatewayAddr);
  }

  //
  // Set the new address by Ip6ConfigProtocol manually.
  //
  Policy = Ip6ConfigPolicyManual;
  Status = Ip6Cfg->SetData (
                     Ip6Cfg,
                     Ip6ConfigDataTypePolicy,
                     sizeof (EFI_IP6_CONFIG_POLICY),
                     &Policy
                     );
  if (EFI_ERROR (Status)) {
    goto ON_EXIT;
  }

  //
  // Create a notify event to set address flag when DAD if IP6 driver succeeded.
  //
  Status = gBS->CreateEvent (
                  EVT_NOTIFY_SIGNAL,
                  TPL_NOTIFY,
                  HttpBootCommonNotify,
                  &IsAddressOk,
                  &MappedEvt
                  );
  if (EFI_ERROR (Status)) {
    goto ON_EXIT;
  }

  //
  // Set static host ip6 address. This is a asynchronous process.
  //
  Status = Ip6Cfg->RegisterDataNotify (
                     Ip6Cfg,
                     Ip6ConfigDataTypeManualAddress,
                     MappedEvt
                     );
  if (EFI_ERROR (Status)) {
    goto ON_EXIT;
  }

  Status = Ip6Cfg->SetData (
                     Ip6Cfg,
                     Ip6ConfigDataTypeManualAddress,
                     sizeof (EFI_IP6_CONFIG_MANUAL_ADDRESS),
                     &CfgAddr
                     );
  if (EFI_ERROR (Status) && (Status != EFI_NOT_READY)) {
    goto ON_EXIT;
  } else if (Status == EFI_NOT_READY) {
    //
    // Poll the network until the asynchronous process is finished.
    //
    while (!IsAddressOk) {
      Ip6->Poll (Ip6);
    }

    //
    // Check whether the Ip6 Address setting is successed.
    //
    DataSize = 0;
    Status   = Ip6Cfg->GetData (
                         Ip6Cfg,
                         Ip6ConfigDataTypeManualAddress,
                         &DataSize,
                         NULL
                         );
    if ((Status != EFI_BUFFER_TOO_SMALL) || (DataSize == 0)) {
      Status = EFI_DEVICE_ERROR;
      goto ON_EXIT;
    }

    Ip6Addr = AllocatePool (DataSize);
    if (Ip6Addr == NULL) {
      return EFI_OUT_OF_RESOURCES;
    }

    Status = Ip6Cfg->GetData (
                       Ip6Cfg,
                       Ip6ConfigDataTypeManualAddress,
                       &DataSize,
                       (VOID *)Ip6Addr
                       );
    if (EFI_ERROR (Status)) {
      Status = EFI_DEVICE_ERROR;
      goto ON_EXIT;
    }

    for (Index = 0; Index < DataSize / sizeof (EFI_IPv6_ADDRESS); Index++) {
      if (CompareMem (Ip6Addr + Index, &CfgAddr, sizeof (EFI_IPv6_ADDRESS)) == 0) {
        break;
      }
    }

    if (Index == DataSize / sizeof (EFI_IPv6_ADDRESS)) {
      Status = EFI_ABORTED;
      goto ON_EXIT;
    }
  }

ON_EXIT:
  if (MappedEvt != NULL) {
    Ip6Cfg->UnregisterDataNotify (
              Ip6Cfg,
              Ip6ConfigDataTypeManualAddress,
              MappedEvt
              );
    gBS->CloseEvent (MappedEvt);
  }

  if (Ip6Addr != NULL) {
    FreePool (Ip6Addr);
  }

  return Status;
}

/**
  Start the S.A.R.R DHCPv6 process to acquire the IPv6 address and other Http boot information.

  @param[in]  Private           Pointer to HTTP_BOOT private data.

  @retval EFI_SUCCESS           The S.A.R.R process successfully finished.
  @retval Others                Failed to finish the S.A.R.R process.

**/
EFI_STATUS
HttpBootDhcp6Sarr (
  IN HTTP_BOOT_PRIVATE_DATA  *Private
  )
{
  EFI_DHCP6_PROTOCOL        *Dhcp6;
  EFI_DHCP6_CONFIG_DATA     Config;
  EFI_DHCP6_MODE_DATA       Mode;
  EFI_DHCP6_RETRANSMISSION  *Retransmit;
  EFI_DHCP6_PACKET_OPTION   *OptList[HTTP_BOOT_DHCP6_OPTION_MAX_NUM];
  UINT32                    OptCount;
  UINT8                     Buffer[HTTP_BOOT_DHCP6_OPTION_MAX_SIZE];
  EFI_STATUS                Status;

  Dhcp6 = Private->Dhcp6;
  ASSERT (Dhcp6 != NULL);

  //
  // Build options list for the request packet.
  //
  OptCount = HttpBootBuildDhcp6Options (Private, OptList, Buffer);
  ASSERT (OptCount > 0);

  Retransmit = AllocateZeroPool (sizeof (EFI_DHCP6_RETRANSMISSION));
  if (Retransmit == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }

  ZeroMem (&Mode, sizeof (EFI_DHCP6_MODE_DATA));
  ZeroMem (&Config, sizeof (EFI_DHCP6_CONFIG_DATA));

  Config.OptionCount           = OptCount;
  Config.OptionList            = OptList;
  Config.Dhcp6Callback         = HttpBootDhcp6CallBack;
  Config.CallbackContext       = Private;
  Config.IaInfoEvent           = NULL;
  Config.RapidCommit           = FALSE;
  Config.ReconfigureAccept     = FALSE;
  Config.IaDescriptor.IaId     = NET_RANDOM (NetRandomInitSeed ());
  Config.IaDescriptor.Type     = EFI_DHCP6_IA_TYPE_NA;
  Config.SolicitRetransmission = Retransmit;
  Retransmit->Irt              = 4;
  Retransmit->Mrc              = 4;
  Retransmit->Mrt              = 32;
  Retransmit->Mrd              = 60;

  //
  // Configure the DHCPv6 instance for HTTP boot.
  //
  Status = Dhcp6->Configure (Dhcp6, &Config);
  FreePool (Retransmit);
  if (EFI_ERROR (Status)) {
    goto ON_EXIT;
  }

  //
  // Initialize the record fields for DHCPv6 offer in private data.
  //
  Private->OfferNum    = 0;
  Private->SelectIndex = 0;
  ZeroMem (Private->OfferCount, sizeof (Private->OfferCount));
  ZeroMem (Private->OfferIndex, sizeof (Private->OfferIndex));

  //
  // Start DHCPv6 S.A.R.R. process to acquire IPv6 address.
  //
  Status = Dhcp6->Start (Dhcp6);
  if (EFI_ERROR (Status)) {
    goto ON_EXIT;
  }

  //
  // Get the acquired IPv6 address and store them.
  //
  Status = Dhcp6->GetModeData (Dhcp6, &Mode, NULL);
  if (EFI_ERROR (Status)) {
    goto ON_EXIT;
  }

  ASSERT (Mode.Ia->State == Dhcp6Bound);
  CopyMem (&Private->StationIp.v6, &Mode.Ia->IaAddress[0].IpAddress, sizeof (EFI_IPv6_ADDRESS));

  AsciiPrint ("\n  Station IPv6 address is ");
  HttpBootShowIp6Addr (&Private->StationIp.v6);
  AsciiPrint ("\n");

ON_EXIT:
  if (EFI_ERROR (Status)) {
    Dhcp6->Stop (Dhcp6);
    Dhcp6->Configure (Dhcp6, NULL);
  } else {
    ZeroMem (&Config, sizeof (EFI_DHCP6_CONFIG_DATA));
    Dhcp6->Configure (Dhcp6, &Config);
    if (Mode.ClientId != NULL) {
      FreePool (Mode.ClientId);
    }

    if (Mode.Ia != NULL) {
      FreePool (Mode.Ia);
    }
  }

  return Status;
}