MdeModulePkg/Universal/Network/Mtftp4Dxe/Mtftp4Wrq.c - edk2 - Git at Google

 /** @file

 Copyright (c) 2006, 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:

   Mtftp4Wrq.c

 Abstract:

   Routines to process Wrq (upload)


 **/

 #include "Mtftp4Impl.h"

 VOID
 Mtftp4WrqInput (
   IN NET_BUF                *UdpPacket,
   IN UDP_POINTS             *Points,
   IN EFI_STATUS             IoStatus,
   IN VOID                   *Context
   );


 /**
   Start the MTFTP session for pload. It will first init some states,
   then send the WRQ request packet, and start receiving the  packet.

   @param  Instance              The MTFTP session
   @param  Operation             Redundant parameter, which is always
                                 EFI_MTFTP4_OPCODE_WRQ here.

   @retval EFI_SUCCESS           The upload process has been started.
   @retval Others                Failed to start the upload.

 **/
 EFI_STATUS
 Mtftp4WrqStart (
   IN MTFTP4_PROTOCOL        *Instance,
   IN UINT16                 Operation
   )
 {
   EFI_STATUS                Status;

   //
   // The valid block number range are [0, 0xffff]. For example:
   // the client sends an WRQ request to the server, the server
   // ACK with an ACK0 to let client start transfer the first
   // packet.
   //
   Status = Mtftp4InitBlockRange (&Instance->Blocks, 0, 0xffff);

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

   Status = Mtftp4SendRequest (Instance);

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

   return UdpIoRecvDatagram (Instance->UnicastPort, Mtftp4WrqInput, Instance, 0);
 }


 /**
   Build then send a MTFTP data packet for the MTFTP upload session.

   @param  Instance              The MTFTP upload session
   @param  BlockNum              The block number to send

   @retval EFI_OUT_OF_RESOURCES  Failed to build the packet
   @retval EFI_ABORTED           The consumer of this child directs to abort the
                                 transmission by return an error through
                                 PacketNeeded
   @retval EFI_SUCCESS           The data is sent.

 **/
 EFI_STATUS
 Mtftp4WrqSendBlock (
   IN MTFTP4_PROTOCOL        *Instance,
   IN UINT16                 BlockNum
   )
 {
   EFI_MTFTP4_PACKET         *Packet;
   EFI_MTFTP4_TOKEN          *Token;
   NET_BUF                   *UdpPacket;
   EFI_STATUS                Status;
   UINT16                    DataLen;
   UINT8                     *DataBuf;
   UINT64                    Start;

   //
   // Allocate a buffer to hold the user data
   //
   UdpPacket = NetbufAlloc (Instance->BlkSize + MTFTP4_DATA_HEAD_LEN);

   if (UdpPacket == NULL) {
     return EFI_OUT_OF_RESOURCES;
   }

   Packet = (EFI_MTFTP4_PACKET *)NetbufAllocSpace (UdpPacket, MTFTP4_DATA_HEAD_LEN, FALSE);

   Packet->Data.OpCode = HTONS (EFI_MTFTP4_OPCODE_DATA);
   Packet->Data.Block  = HTONS (BlockNum);

   //
   // Read the block from either the buffer or PacketNeeded callback
   //
   Token   = Instance->Token;
   DataLen = Instance->BlkSize;

   if (Token->Buffer != NULL) {
     Start = MultU64x32 (BlockNum - 1, Instance->BlkSize);

     if (Token->BufferSize < Start + Instance->BlkSize) {
       DataLen             = (UINT16) (Token->BufferSize - Start);
       Instance->LastBlock = BlockNum;
       Mtftp4SetLastBlockNum (&Instance->Blocks, BlockNum);
     }

     if (DataLen > 0) {
       NetbufAllocSpace (UdpPacket, DataLen, FALSE);
       NetCopyMem (Packet->Data.Data, (UINT8 *) Token->Buffer + Start, DataLen);
     }

   } else {
     //
     // Get data from PacketNeeded
     //
     DataBuf = NULL;
     Status  = Token->PacketNeeded (&Instance->Mtftp4, Token, &DataLen, (VOID **) &DataBuf);

     if (EFI_ERROR (Status) || (DataLen > Instance->BlkSize)) {
       if (DataBuf != NULL) {
         gBS->FreePool (DataBuf);
       }

       Mtftp4SendError (
         Instance,
         EFI_MTFTP4_ERRORCODE_REQUEST_DENIED,
         "User aborted the transfer"
         );

       return EFI_ABORTED;
     }

     if (DataLen < Instance->BlkSize) {
       Instance->LastBlock = BlockNum;
       Mtftp4SetLastBlockNum (&Instance->Blocks, BlockNum);
     }

     if (DataLen > 0) {
       NetbufAllocSpace (UdpPacket, DataLen, FALSE);
       NetCopyMem (Packet->Data.Data, DataBuf, DataLen);
       gBS->FreePool (DataBuf);
     }
   }

   return Mtftp4SendPacket (Instance, UdpPacket);
 }


 /**
   Function to handle received ACK packet. If the ACK number matches the
   expected block number, and there are more data pending, send the next
   block. Otherwise tell the caller that we are done.

   @param  Instance              The MTFTP upload session
   @param  Packet                The MTFTP packet received
   @param  Len                   The packet length
   @param  Completed             Return whether the upload has finished.

   @retval EFI_SUCCESS           The ACK is successfully processed.
   @retval EFI_TFTP_ERROR        The block number loops back.
   @retval Others                Failed to transmit the next data packet.

 **/
 EFI_STATUS
 Mtftp4WrqHandleAck (
   IN  MTFTP4_PROTOCOL       *Instance,
   IN  EFI_MTFTP4_PACKET     *Packet,
   IN  UINT32                Len,
   OUT BOOLEAN               *Completed
   )
 {
   UINT16                    AckNum;
   INTN                      Expected;

   *Completed  = FALSE;
   AckNum      = NTOHS (Packet->Ack.Block[0]);
   Expected    = Mtftp4GetNextBlockNum (&Instance->Blocks);

   ASSERT (Expected >= 0);

   //
   // Get an unwanted ACK, return EFI_SUCCESS to let Mtftp4WrqInput
   // restart receive.
   //
   if (Expected != AckNum) {
     return EFI_SUCCESS;
   }

   //
   // Remove the acked block number, if this is the last block number,
   // tell the Mtftp4WrqInput to finish the transfer. This is the last
   // block number if the block range are empty..
   //
   Mtftp4RemoveBlockNum (&Instance->Blocks, AckNum);

   Expected = Mtftp4GetNextBlockNum (&Instance->Blocks);

   if (Expected < 0) {
     //
     // The block range is empty. It may either because the the last
     // block has been ACKed, or the sequence number just looped back,
     // that is, there is more than 0xffff blocks.
     //
     if (Instance->LastBlock == AckNum) {
       ASSERT (Instance->LastBlock >= 1);
       *Completed = TRUE;
       return EFI_SUCCESS;

     } else {
       Mtftp4SendError (
         Instance,
         EFI_MTFTP4_ERRORCODE_REQUEST_DENIED,
         "Block number rolls back, not supported, try blksize option"
         );

       return EFI_TFTP_ERROR;
     }
   }

   return Mtftp4WrqSendBlock (Instance, (UINT16) Expected);
 }


 /**
   Check whether the received OACK is valid. The OACK is valid
   only if:
   1. It only include options requested by us
   2. It can only include a smaller block size
   3. It can't change the proposed time out value.
   4. Other requirements of the individal MTFTP options as required.s

   @param  Reply                 The options included in the OACK
   @param  Request               The options we requested

   @return TRUE if the options included in OACK is valid, otherwise FALSE.

 **/
 BOOLEAN
 Mtftp4WrqOackValid (
   IN MTFTP4_OPTION              *Reply,
   IN MTFTP4_OPTION              *Request
   )
 {
   //
   // It is invalid for server to return options we don't request
   //
   if ((Reply->Exist &~Request->Exist) != 0) {
     return FALSE;
   }

   //
   // Server can only specify a smaller block size to be used and
   // return the timeout matches that requested.
   //
   if (((Reply->Exist & MTFTP4_BLKSIZE_EXIST) && (Reply->BlkSize > Request->BlkSize)) ||
       ((Reply->Exist & MTFTP4_TIMEOUT_EXIST) && (Reply->Timeout != Request->Timeout))) {
     return FALSE;
   }

   return TRUE;
 }


 /**
   Function to handle the MTFTP OACK packet. It parses the packet's
   options, and update the internal states of the session

   @param  Instance              The MTFTP session
   @param  Packet                The received OACK packet
   @param  Len                   The length of the packet
   @param  Completed             Whether the transmisson has completed. NOT used by
                                 this function.

   @retval EFI_SUCCESS           The OACK process is OK
   @retval EFI_TFTP_ERROR        Some error occured, and the session reset.

 **/
 EFI_STATUS
 Mtftp4WrqHandleOack (
   IN  MTFTP4_PROTOCOL       *Instance,
   IN  EFI_MTFTP4_PACKET     *Packet,
   IN  UINT32                Len,
   OUT BOOLEAN               *Completed
   )
 {
   MTFTP4_OPTION             Reply;
   EFI_MTFTP4_PACKET         Bogus;
   EFI_STATUS                Status;
   INTN                      Expected;

   *Completed = FALSE;

   //
   // Ignore the OACK if already started the upload
   //
   Expected = Mtftp4GetNextBlockNum (&Instance->Blocks);

   if (Expected != 0) {
     return EFI_SUCCESS;
   }

   //
   // Parse and validate the options from server
   //
   NetZeroMem (&Reply, sizeof (MTFTP4_OPTION));
   Status = Mtftp4ParseOptionOack (Packet, Len, &Reply);

   if (EFI_ERROR (Status) || !Mtftp4WrqOackValid (&Reply, &Instance->RequestOption)) {
     //
     // Don't send a MTFTP error packet when out of resource, it can
     // only make it worse.
     //
     if (Status != EFI_OUT_OF_RESOURCES) {
       Mtftp4SendError (
         Instance,
         EFI_MTFTP4_ERRORCODE_ILLEGAL_OPERATION,
         "Mal-formated OACK packet"
         );
     }

     return EFI_TFTP_ERROR;
   }

   if (Reply.BlkSize != 0) {
     Instance->BlkSize = Reply.BlkSize;
   }

   if (Reply.Timeout != 0) {
     Instance->Timeout = Reply.Timeout;
   }

   //
   // Build a bogus ACK0 packet then pass it to the Mtftp4WrqHandleAck,
   // which will start the transmission of the first data block.
   //
   Bogus.Ack.OpCode    = HTONS (EFI_MTFTP4_OPCODE_ACK);
   Bogus.Ack.Block[0]  = 0;

   return Mtftp4WrqHandleAck (Instance, &Bogus, sizeof (EFI_MTFTP4_ACK_HEADER), Completed);
 }


 /**
   The input process routine for MTFTP upload.

   @param  UdpPacket             The received MTFTP packet.
   @param  Points                The local/remote access point
   @param  IoStatus              The result of the packet receiving
   @param  Context               Opaque parameter for the callback, which is the
                                 MTFTP session.

   @return None

 **/
 VOID
 Mtftp4WrqInput (
   IN NET_BUF                *UdpPacket,
   IN UDP_POINTS             *Points,
   IN EFI_STATUS             IoStatus,
   IN VOID                   *Context
   )
 {
   MTFTP4_PROTOCOL           *Instance;
   EFI_MTFTP4_PACKET         *Packet;
   BOOLEAN                   Completed;
   EFI_STATUS                Status;
   UINT32                    Len;
   UINT16                    Opcode;

   Instance = (MTFTP4_PROTOCOL *) Context;
   NET_CHECK_SIGNATURE (Instance, MTFTP4_PROTOCOL_SIGNATURE);

   Completed = FALSE;
   Packet    = NULL;
   Status    = EFI_SUCCESS;

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

   ASSERT (UdpPacket != NULL);

   if (UdpPacket->TotalSize < MTFTP4_OPCODE_LEN) {
     goto ON_EXIT;
   }

   //
   // Client send initial request to server's listening port. Server
   // will select a UDP port to communicate with the client.
   //
   if (Points->RemotePort != Instance->ConnectedPort) {
     if (Instance->ConnectedPort != 0) {
       goto ON_EXIT;
     } else {
       Instance->ConnectedPort = Points->RemotePort;
     }
   }

   //
   // Copy the MTFTP packet to a continuous buffer if it isn't already so.
   //
   Len = UdpPacket->TotalSize;

   if (UdpPacket->BlockOpNum > 1) {
     Packet = NetAllocatePool (Len);

     if (Packet == NULL) {
       Status = EFI_OUT_OF_RESOURCES;
       goto ON_EXIT;
     }

     NetbufCopy (UdpPacket, 0, Len, (UINT8 *) Packet);

   } else {
     Packet = (EFI_MTFTP4_PACKET *) NetbufGetByte (UdpPacket, 0, NULL);
   }

   Opcode = NTOHS (Packet->OpCode);

   //
   // Call the user's CheckPacket if provided. Abort the transmission
   // if CheckPacket returns an EFI_ERROR code.
   //
   if ((Instance->Token->CheckPacket != NULL) &&
       ((Opcode == EFI_MTFTP4_OPCODE_OACK) || (Opcode == EFI_MTFTP4_OPCODE_ERROR))) {

     Status = Instance->Token->CheckPacket (
                                 &Instance->Mtftp4,
                                 Instance->Token,
                                 (UINT16) Len,
                                 Packet
                                 );

     if (EFI_ERROR (Status)) {
       //
       // Send an error message to the server to inform it
       //
       if (Opcode != EFI_MTFTP4_OPCODE_ERROR) {
         Mtftp4SendError (
           Instance,
           EFI_MTFTP4_ERRORCODE_REQUEST_DENIED,
           "User aborted the transfer"
           );
       }

       Status = EFI_ABORTED;
       goto ON_EXIT;
     }
   }

   switch (Opcode) {
   case EFI_MTFTP4_OPCODE_ACK:
     if (Len != MTFTP4_OPCODE_LEN + MTFTP4_BLKNO_LEN) {
       goto ON_EXIT;
     }

     Status = Mtftp4WrqHandleAck (Instance, Packet, Len, &Completed);
     break;

   case EFI_MTFTP4_OPCODE_OACK:
     if (Len <= MTFTP4_OPCODE_LEN) {
       goto ON_EXIT;
     }

     Status = Mtftp4WrqHandleOack (Instance, Packet, Len, &Completed);
     break;

   case EFI_MTFTP4_OPCODE_ERROR:
     Status = EFI_TFTP_ERROR;
     break;
   }

 ON_EXIT:
   //
   // Free the resources, then if !EFI_ERROR (Status) and not completed,
   // restart the receive, otherwise end the session.
   //
   if ((Packet != NULL) && (UdpPacket->BlockOpNum > 1)) {
     NetFreePool (Packet);
   }

   if (UdpPacket != NULL) {
     NetbufFree (UdpPacket);
   }

   if (!EFI_ERROR (Status) && !Completed) {
     Status = UdpIoRecvDatagram (Instance->UnicastPort, Mtftp4WrqInput, Instance, 0);
   }

   //
   // Status may have been updated by UdpIoRecvDatagram
   //
   if (EFI_ERROR (Status) || Completed) {
     Mtftp4CleanOperation (Instance, Status);
   }
 }
	/** @file

	Copyright (c) 2006, 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:

	Mtftp4Wrq.c

	Abstract:

	Routines to process Wrq (upload)


	**/

	#include "Mtftp4Impl.h"

	VOID
	Mtftp4WrqInput (
	IN NET_BUF *UdpPacket,
	IN UDP_POINTS *Points,
	IN EFI_STATUS IoStatus,
	IN VOID *Context
	);


	/**
	Start the MTFTP session for pload. It will first init some states,
	then send the WRQ request packet, and start receiving the packet.

	@param Instance The MTFTP session
	@param Operation Redundant parameter, which is always
	EFI_MTFTP4_OPCODE_WRQ here.

	@retval EFI_SUCCESS The upload process has been started.
	@retval Others Failed to start the upload.

	**/
	EFI_STATUS
	Mtftp4WrqStart (
	IN MTFTP4_PROTOCOL *Instance,
	IN UINT16 Operation
	)
	{
	EFI_STATUS Status;

	//
	// The valid block number range are [0, 0xffff]. For example:
	// the client sends an WRQ request to the server, the server
	// ACK with an ACK0 to let client start transfer the first
	// packet.
	//
	Status = Mtftp4InitBlockRange (&Instance->Blocks, 0, 0xffff);

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

	Status = Mtftp4SendRequest (Instance);

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

	return UdpIoRecvDatagram (Instance->UnicastPort, Mtftp4WrqInput, Instance, 0);
	}


	/**
	Build then send a MTFTP data packet for the MTFTP upload session.

	@param Instance The MTFTP upload session
	@param BlockNum The block number to send

	@retval EFI_OUT_OF_RESOURCES Failed to build the packet
	@retval EFI_ABORTED The consumer of this child directs to abort the
	transmission by return an error through
	PacketNeeded
	@retval EFI_SUCCESS The data is sent.

	**/
	EFI_STATUS
	Mtftp4WrqSendBlock (
	IN MTFTP4_PROTOCOL *Instance,
	IN UINT16 BlockNum
	)
	{
	EFI_MTFTP4_PACKET *Packet;
	EFI_MTFTP4_TOKEN *Token;
	NET_BUF *UdpPacket;
	EFI_STATUS Status;
	UINT16 DataLen;
	UINT8 *DataBuf;
	UINT64 Start;

	//
	// Allocate a buffer to hold the user data
	//
	UdpPacket = NetbufAlloc (Instance->BlkSize + MTFTP4_DATA_HEAD_LEN);

	if (UdpPacket == NULL) {
	return EFI_OUT_OF_RESOURCES;
	}

	Packet = (EFI_MTFTP4_PACKET *)NetbufAllocSpace (UdpPacket, MTFTP4_DATA_HEAD_LEN, FALSE);

	Packet->Data.OpCode = HTONS (EFI_MTFTP4_OPCODE_DATA);
	Packet->Data.Block = HTONS (BlockNum);

	//
	// Read the block from either the buffer or PacketNeeded callback
	//
	Token = Instance->Token;
	DataLen = Instance->BlkSize;

	if (Token->Buffer != NULL) {
	Start = MultU64x32 (BlockNum - 1, Instance->BlkSize);

	if (Token->BufferSize < Start + Instance->BlkSize) {
	DataLen = (UINT16) (Token->BufferSize - Start);
	Instance->LastBlock = BlockNum;
	Mtftp4SetLastBlockNum (&Instance->Blocks, BlockNum);
	}

	if (DataLen > 0) {
	NetbufAllocSpace (UdpPacket, DataLen, FALSE);
	NetCopyMem (Packet->Data.Data, (UINT8 *) Token->Buffer + Start, DataLen);
	}

	} else {
	//
	// Get data from PacketNeeded
	//
	DataBuf = NULL;
	Status = Token->PacketNeeded (&Instance->Mtftp4, Token, &DataLen, (VOID **) &DataBuf);

	if (EFI_ERROR (Status) \|\| (DataLen > Instance->BlkSize)) {
	if (DataBuf != NULL) {
	gBS->FreePool (DataBuf);
	}

	Mtftp4SendError (
	Instance,
	EFI_MTFTP4_ERRORCODE_REQUEST_DENIED,
	"User aborted the transfer"
	);

	return EFI_ABORTED;
	}

	if (DataLen < Instance->BlkSize) {
	Instance->LastBlock = BlockNum;
	Mtftp4SetLastBlockNum (&Instance->Blocks, BlockNum);
	}

	if (DataLen > 0) {
	NetbufAllocSpace (UdpPacket, DataLen, FALSE);
	NetCopyMem (Packet->Data.Data, DataBuf, DataLen);
	gBS->FreePool (DataBuf);
	}
	}

	return Mtftp4SendPacket (Instance, UdpPacket);
	}


	/**
	Function to handle received ACK packet. If the ACK number matches the
	expected block number, and there are more data pending, send the next
	block. Otherwise tell the caller that we are done.

	@param Instance The MTFTP upload session
	@param Packet The MTFTP packet received
	@param Len The packet length
	@param Completed Return whether the upload has finished.

	@retval EFI_SUCCESS The ACK is successfully processed.
	@retval EFI_TFTP_ERROR The block number loops back.
	@retval Others Failed to transmit the next data packet.

	**/
	EFI_STATUS
	Mtftp4WrqHandleAck (
	IN MTFTP4_PROTOCOL *Instance,
	IN EFI_MTFTP4_PACKET *Packet,
	IN UINT32 Len,
	OUT BOOLEAN *Completed
	)
	{
	UINT16 AckNum;
	INTN Expected;

	*Completed = FALSE;
	AckNum = NTOHS (Packet->Ack.Block[0]);
	Expected = Mtftp4GetNextBlockNum (&Instance->Blocks);

	ASSERT (Expected >= 0);

	//
	// Get an unwanted ACK, return EFI_SUCCESS to let Mtftp4WrqInput
	// restart receive.
	//
	if (Expected != AckNum) {
	return EFI_SUCCESS;
	}

	//
	// Remove the acked block number, if this is the last block number,
	// tell the Mtftp4WrqInput to finish the transfer. This is the last
	// block number if the block range are empty..
	//
	Mtftp4RemoveBlockNum (&Instance->Blocks, AckNum);

	Expected = Mtftp4GetNextBlockNum (&Instance->Blocks);

	if (Expected < 0) {
	//
	// The block range is empty. It may either because the the last
	// block has been ACKed, or the sequence number just looped back,
	// that is, there is more than 0xffff blocks.
	//
	if (Instance->LastBlock == AckNum) {
	ASSERT (Instance->LastBlock >= 1);
	*Completed = TRUE;
	return EFI_SUCCESS;

	} else {
	Mtftp4SendError (
	Instance,
	EFI_MTFTP4_ERRORCODE_REQUEST_DENIED,
	"Block number rolls back, not supported, try blksize option"
	);

	return EFI_TFTP_ERROR;
	}
	}

	return Mtftp4WrqSendBlock (Instance, (UINT16) Expected);
	}


	/**
	Check whether the received OACK is valid. The OACK is valid
	only if:
	1. It only include options requested by us
	2. It can only include a smaller block size
	3. It can't change the proposed time out value.
	4. Other requirements of the individal MTFTP options as required.s

	@param Reply The options included in the OACK
	@param Request The options we requested

	@return TRUE if the options included in OACK is valid, otherwise FALSE.

	**/
	BOOLEAN
	Mtftp4WrqOackValid (
	IN MTFTP4_OPTION *Reply,
	IN MTFTP4_OPTION *Request
	)
	{
	//
	// It is invalid for server to return options we don't request
	//
	if ((Reply->Exist &~Request->Exist) != 0) {
	return FALSE;
	}

	//
	// Server can only specify a smaller block size to be used and
	// return the timeout matches that requested.
	//
	if (((Reply->Exist & MTFTP4_BLKSIZE_EXIST) && (Reply->BlkSize > Request->BlkSize)) \|\|
	((Reply->Exist & MTFTP4_TIMEOUT_EXIST) && (Reply->Timeout != Request->Timeout))) {
	return FALSE;
	}

	return TRUE;
	}


	/**
	Function to handle the MTFTP OACK packet. It parses the packet's
	options, and update the internal states of the session

	@param Instance The MTFTP session
	@param Packet The received OACK packet
	@param Len The length of the packet
	@param Completed Whether the transmisson has completed. NOT used by
	this function.

	@retval EFI_SUCCESS The OACK process is OK
	@retval EFI_TFTP_ERROR Some error occured, and the session reset.

	**/
	EFI_STATUS
	Mtftp4WrqHandleOack (
	IN MTFTP4_PROTOCOL *Instance,
	IN EFI_MTFTP4_PACKET *Packet,
	IN UINT32 Len,
	OUT BOOLEAN *Completed
	)
	{
	MTFTP4_OPTION Reply;
	EFI_MTFTP4_PACKET Bogus;
	EFI_STATUS Status;
	INTN Expected;

	*Completed = FALSE;

	//
	// Ignore the OACK if already started the upload
	//
	Expected = Mtftp4GetNextBlockNum (&Instance->Blocks);

	if (Expected != 0) {
	return EFI_SUCCESS;
	}

	//
	// Parse and validate the options from server
	//
	NetZeroMem (&Reply, sizeof (MTFTP4_OPTION));
	Status = Mtftp4ParseOptionOack (Packet, Len, &Reply);

	if (EFI_ERROR (Status) \|\| !Mtftp4WrqOackValid (&Reply, &Instance->RequestOption)) {
	//
	// Don't send a MTFTP error packet when out of resource, it can
	// only make it worse.
	//
	if (Status != EFI_OUT_OF_RESOURCES) {
	Mtftp4SendError (
	Instance,
	EFI_MTFTP4_ERRORCODE_ILLEGAL_OPERATION,
	"Mal-formated OACK packet"
	);
	}

	return EFI_TFTP_ERROR;
	}

	if (Reply.BlkSize != 0) {
	Instance->BlkSize = Reply.BlkSize;
	}

	if (Reply.Timeout != 0) {
	Instance->Timeout = Reply.Timeout;
	}

	//
	// Build a bogus ACK0 packet then pass it to the Mtftp4WrqHandleAck,
	// which will start the transmission of the first data block.
	//
	Bogus.Ack.OpCode = HTONS (EFI_MTFTP4_OPCODE_ACK);
	Bogus.Ack.Block[0] = 0;

	return Mtftp4WrqHandleAck (Instance, &Bogus, sizeof (EFI_MTFTP4_ACK_HEADER), Completed);
	}


	/**
	The input process routine for MTFTP upload.

	@param UdpPacket The received MTFTP packet.
	@param Points The local/remote access point
	@param IoStatus The result of the packet receiving
	@param Context Opaque parameter for the callback, which is the
	MTFTP session.

	@return None

	**/
	VOID
	Mtftp4WrqInput (
	IN NET_BUF *UdpPacket,
	IN UDP_POINTS *Points,
	IN EFI_STATUS IoStatus,
	IN VOID *Context
	)
	{
	MTFTP4_PROTOCOL *Instance;
	EFI_MTFTP4_PACKET *Packet;
	BOOLEAN Completed;
	EFI_STATUS Status;
	UINT32 Len;
	UINT16 Opcode;

	Instance = (MTFTP4_PROTOCOL *) Context;
	NET_CHECK_SIGNATURE (Instance, MTFTP4_PROTOCOL_SIGNATURE);

	Completed = FALSE;
	Packet = NULL;
	Status = EFI_SUCCESS;

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

	ASSERT (UdpPacket != NULL);

	if (UdpPacket->TotalSize < MTFTP4_OPCODE_LEN) {
	goto ON_EXIT;
	}

	//
	// Client send initial request to server's listening port. Server
	// will select a UDP port to communicate with the client.
	//
	if (Points->RemotePort != Instance->ConnectedPort) {
	if (Instance->ConnectedPort != 0) {
	goto ON_EXIT;
	} else {
	Instance->ConnectedPort = Points->RemotePort;
	}
	}

	//
	// Copy the MTFTP packet to a continuous buffer if it isn't already so.
	//
	Len = UdpPacket->TotalSize;

	if (UdpPacket->BlockOpNum > 1) {
	Packet = NetAllocatePool (Len);

	if (Packet == NULL) {
	Status = EFI_OUT_OF_RESOURCES;
	goto ON_EXIT;
	}

	NetbufCopy (UdpPacket, 0, Len, (UINT8 *) Packet);

	} else {
	Packet = (EFI_MTFTP4_PACKET *) NetbufGetByte (UdpPacket, 0, NULL);
	}

	Opcode = NTOHS (Packet->OpCode);

	//
	// Call the user's CheckPacket if provided. Abort the transmission
	// if CheckPacket returns an EFI_ERROR code.
	//
	if ((Instance->Token->CheckPacket != NULL) &&
	((Opcode == EFI_MTFTP4_OPCODE_OACK) \|\| (Opcode == EFI_MTFTP4_OPCODE_ERROR))) {

	Status = Instance->Token->CheckPacket (
	&Instance->Mtftp4,
	Instance->Token,
	(UINT16) Len,
	Packet
	);

	if (EFI_ERROR (Status)) {
	//
	// Send an error message to the server to inform it
	//
	if (Opcode != EFI_MTFTP4_OPCODE_ERROR) {
	Mtftp4SendError (
	Instance,
	EFI_MTFTP4_ERRORCODE_REQUEST_DENIED,
	"User aborted the transfer"
	);
	}

	Status = EFI_ABORTED;
	goto ON_EXIT;
	}
	}

	switch (Opcode) {
	case EFI_MTFTP4_OPCODE_ACK:
	if (Len != MTFTP4_OPCODE_LEN + MTFTP4_BLKNO_LEN) {
	goto ON_EXIT;
	}

	Status = Mtftp4WrqHandleAck (Instance, Packet, Len, &Completed);
	break;

	case EFI_MTFTP4_OPCODE_OACK:
	if (Len <= MTFTP4_OPCODE_LEN) {
	goto ON_EXIT;
	}

	Status = Mtftp4WrqHandleOack (Instance, Packet, Len, &Completed);
	break;

	case EFI_MTFTP4_OPCODE_ERROR:
	Status = EFI_TFTP_ERROR;
	break;
	}

	ON_EXIT:
	//
	// Free the resources, then if !EFI_ERROR (Status) and not completed,
	// restart the receive, otherwise end the session.
	//
	if ((Packet != NULL) && (UdpPacket->BlockOpNum > 1)) {
	NetFreePool (Packet);
	}

	if (UdpPacket != NULL) {
	NetbufFree (UdpPacket);
	}

	if (!EFI_ERROR (Status) && !Completed) {
	Status = UdpIoRecvDatagram (Instance->UnicastPort, Mtftp4WrqInput, Instance, 0);
	}

	//
	// Status may have been updated by UdpIoRecvDatagram
	//
	if (EFI_ERROR (Status) \|\| Completed) {
	Mtftp4CleanOperation (Instance, Status);
	}
	}