[mirror_edk2.git] / MdeModulePkg / Universal / Network / Tcp4Dxe / SockImpl.c

/** @file
  Implementation of the Socket.

Copyright (c) 2005 - 2009, Intel Corporation<BR>
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<BR>

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

**/

#include "SockImpl.h"

/**
  Get the length of the data that can be retrieved from the socket
  receive buffer.

  @param  SockBuffer            Pointer to the socket receive buffer.
  @param  IsUrg                 Pointer to a BOOLEAN variable. If TRUE the data is
                                OOB.
  @param  BufLen                The maximum length of the data buffer to store the
                                received data in socket layer.

  @return The length of the data can be retreived.

**/
UINT32
SockTcpDataToRcv (
  IN     SOCK_BUFFER    *SockBuffer,
     OUT BOOLEAN        *IsUrg,
  IN     UINT32         BufLen
  );
  
/**
  Process the send token.

  @param  Sock                  Pointer to the socket.

**/
VOID
SockProcessSndToken (
  IN OUT SOCKET *Sock
  );

/**
  Supporting function for both SockImpl and SockInterface.

  @param Event             The Event this notify function registered to, ignored.
  
**/
VOID
SockFreeFoo (
  IN EFI_EVENT Event
  )
{
  return ;
}


/**
  Get the length of the data that can be retrieved from the socket
  receive buffer.

  @param  SockBuffer            Pointer to the socket receive buffer.
  @param  IsUrg                 Pointer to a BOOLEAN variable. If TRUE the data is
                                OOB.
  @param  BufLen                The maximum length of the data buffer to store the
                                received data in socket layer.

  @return The length of the data can be retreived.

**/
UINT32
SockTcpDataToRcv (
  IN     SOCK_BUFFER    *SockBuffer,
     OUT BOOLEAN        *IsUrg,
  IN     UINT32         BufLen
  )
{
  NET_BUF       *RcvBufEntry;
  UINT32        DataLen;
  TCP_RSV_DATA  *TcpRsvData;
  BOOLEAN       Urg;
  ASSERT ((SockBuffer != NULL) && (IsUrg != NULL) && (BufLen > 0));

  RcvBufEntry = SockBufFirst (SockBuffer);
  ASSERT (RcvBufEntry != NULL);

  TcpRsvData  = (TCP_RSV_DATA *) RcvBufEntry->ProtoData;

  *IsUrg      = (BOOLEAN) ((TcpRsvData->UrgLen > 0) ? TRUE : FALSE);

  if (*IsUrg && TcpRsvData->UrgLen < RcvBufEntry->TotalSize) {

    DataLen = MIN (TcpRsvData->UrgLen, BufLen);

    if (DataLen < TcpRsvData->UrgLen) {
      TcpRsvData->UrgLen = TcpRsvData->UrgLen - DataLen;
    } else {
      TcpRsvData->UrgLen = 0;
    }

    return DataLen;

  }

  DataLen     = RcvBufEntry->TotalSize;

  RcvBufEntry = SockBufNext (SockBuffer, RcvBufEntry);

  while ((BufLen > DataLen) && (RcvBufEntry != NULL)) {

    TcpRsvData  = (TCP_RSV_DATA *) RcvBufEntry->ProtoData;

    Urg         = (BOOLEAN) ((TcpRsvData->UrgLen > 0) ? TRUE : FALSE);

    if (*IsUrg != Urg) {
      break;
    }

    if (*IsUrg && TcpRsvData->UrgLen < RcvBufEntry->TotalSize) {

      if (TcpRsvData->UrgLen + DataLen < BufLen) {
        TcpRsvData->UrgLen = 0;
      } else {
        TcpRsvData->UrgLen = TcpRsvData->UrgLen - (BufLen - DataLen);
      }

      return MIN (TcpRsvData->UrgLen + DataLen, BufLen);

    }

    DataLen += RcvBufEntry->TotalSize;

    RcvBufEntry = SockBufNext (SockBuffer, RcvBufEntry);
  }

  DataLen = MIN (BufLen, DataLen);
  return DataLen;
}


/**
  Copy data from socket buffer to application provided receive buffer.

  @param  Sock                  Pointer to the socket.
  @param  TcpRxData             Pointer to the application provided receive buffer.
  @param  RcvdBytes             The maximum length of the data can be copied.
  @param  IsOOB                 If TURE the data is OOB, FALSE the data is normal.

**/
VOID
SockSetTcpRxData (
  IN SOCKET     *Sock,
  IN VOID       *TcpRxData,
  IN UINT32     RcvdBytes,
  IN BOOLEAN    IsOOB
  )
{
  UINT32                  Index;
  UINT32                  CopyBytes;
  UINT32                  OffSet;
  EFI_TCP4_RECEIVE_DATA   *RxData;
  EFI_TCP4_FRAGMENT_DATA  *Fragment;

  RxData  = (EFI_TCP4_RECEIVE_DATA *) TcpRxData;

  OffSet  = 0;

  ASSERT (RxData->DataLength >= RcvdBytes);

  RxData->DataLength  = RcvdBytes;
  RxData->UrgentFlag  = IsOOB;

  for (Index = 0; (Index < RxData->FragmentCount) && (RcvdBytes > 0); Index++) {

    Fragment  = &RxData->FragmentTable[Index];
    CopyBytes = MIN ((UINT32) (Fragment->FragmentLength), RcvdBytes);

    NetbufQueCopy (
      Sock->RcvBuffer.DataQueue,
      OffSet,
      CopyBytes,
      Fragment->FragmentBuffer
      );

    Fragment->FragmentLength = CopyBytes;
    RcvdBytes -= CopyBytes;
    OffSet += CopyBytes;
  }
}


/**
  Get received data from the socket layer to the receive token.

  @param  Sock                  Pointer to the socket.
  @param  RcvToken              Pointer to the application provided receive token.

  @return The length of data received in this token.

**/
UINT32
SockProcessRcvToken (
  IN     SOCKET        *Sock,
  IN OUT SOCK_IO_TOKEN *RcvToken
  )
{
  UINT32                 TokenRcvdBytes;
  EFI_TCP4_RECEIVE_DATA  *RxData;
  BOOLEAN                IsUrg;

  ASSERT (Sock != NULL);

  ASSERT (SockStream == Sock->Type);

  RxData = RcvToken->Packet.RxData;

  TokenRcvdBytes = SockTcpDataToRcv (
                      &Sock->RcvBuffer,
                      &IsUrg,
                      (UINT32) RxData->DataLength
                      );

  //
  // Copy data from RcvBuffer of socket to user
  // provided RxData and set the fields in TCP RxData
  //
  SockSetTcpRxData (Sock, RxData, TokenRcvdBytes, IsUrg);

  NetbufQueTrim (Sock->RcvBuffer.DataQueue, TokenRcvdBytes);
  SIGNAL_TOKEN (&(RcvToken->Token), EFI_SUCCESS);

  return TokenRcvdBytes;
}


/**
  Process the TCP send data, buffer the tcp txdata and append
  the buffer to socket send buffer,then try to send it.

  @param  Sock                  Pointer to the socket.
  @param  TcpTxData             Pointer to the application provided send buffer.

  @retval EFI_SUCCESS           The operation is completed successfully.
  @retval EFI_OUT_OF_RESOURCES  Failed due to resource limit.

**/
EFI_STATUS
SockProcessTcpSndData (
  IN SOCKET   *Sock,
  IN VOID     *TcpTxData
  )
{
  NET_BUF                 *SndData;
  EFI_STATUS              Status;
  EFI_TCP4_TRANSMIT_DATA  *TxData;

  TxData = (EFI_TCP4_TRANSMIT_DATA *) TcpTxData;

  //
  // transform this TxData into a NET_BUFFER
  // and insert it into Sock->SndBuffer
  //
  SndData = NetbufFromExt (
              (NET_FRAGMENT *) TxData->FragmentTable,
              (UINT32) TxData->FragmentCount,
              0,
              0,
              SockFreeFoo,
              NULL
              );

  if (NULL == SndData) {
    DEBUG ((EFI_D_ERROR, "SockKProcessSndData: Failed to"
      " call NetBufferFromExt\n"));

    return EFI_OUT_OF_RESOURCES;
  }

  NetbufQueAppend (Sock->SndBuffer.DataQueue, SndData);

  //
  // notify the low layer protocol to handle this send token
  //
  if (TxData->Urgent) {
    Status = Sock->ProtoHandler (Sock, SOCK_SNDURG, NULL);

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

  if (TxData->Push) {
    Status = Sock->ProtoHandler (Sock, SOCK_SNDPUSH, NULL);

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

  //
  // low layer protocol should really handle the sending
  // process when catching SOCK_SND request
  //
  Status = Sock->ProtoHandler (Sock, SOCK_SND, NULL);

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

  return EFI_SUCCESS;
}


/**
  Flush the tokens in the specific token list.

  @param  Sock                  Pointer to the socket.
  @param  PendingTokenList      Pointer to the token list to be flushed.
  
**/
VOID
SockFlushPendingToken (
  IN SOCKET         *Sock,
  IN LIST_ENTRY     *PendingTokenList
  )
{
  SOCK_TOKEN            *SockToken;
  SOCK_COMPLETION_TOKEN *Token;

  ASSERT ((Sock != NULL) && (PendingTokenList != NULL));

  while (!IsListEmpty (PendingTokenList)) {
    SockToken = NET_LIST_HEAD (
                  PendingTokenList,
                  SOCK_TOKEN,
                  TokenList
                  );

    Token = SockToken->Token;
    SIGNAL_TOKEN (Token, Sock->SockError);

    RemoveEntryList (&(SockToken->TokenList));
    FreePool (SockToken);
  }
}


/**
  Wake up the connection token while the connection is successfully established, 
  then try to process any pending send token.

  @param  Sock                  Pointer to the socket.

**/
VOID
SockWakeConnToken (
  IN OUT SOCKET *Sock
  )
{
  ASSERT (Sock->ConnectionToken != NULL);

  SIGNAL_TOKEN (Sock->ConnectionToken, EFI_SUCCESS);
  Sock->ConnectionToken = NULL;

  //
  // check to see if some pending send token existed?
  //
  SockProcessSndToken (Sock);
  return ;
}


/**
  Wake up the listen token while the connection is established successfully.

  @param  Sock                  Pointer to the socket.

**/
VOID
SockWakeListenToken (
  IN OUT SOCKET *Sock
  )
{
  SOCKET                *Parent;
  SOCK_TOKEN            *SockToken;
  EFI_TCP4_LISTEN_TOKEN *ListenToken;

  Parent = Sock->Parent;

  ASSERT ((Parent != NULL) && SOCK_IS_LISTENING (Parent) && SOCK_IS_CONNECTED (Sock));

  if (!IsListEmpty (&Parent->ListenTokenList)) {
    SockToken = NET_LIST_HEAD (
                  &Parent->ListenTokenList,
                  SOCK_TOKEN,
                  TokenList
                  );

    ListenToken = (EFI_TCP4_LISTEN_TOKEN *) SockToken->Token;
    ListenToken->NewChildHandle = Sock->SockHandle;

    SIGNAL_TOKEN (&(ListenToken->CompletionToken), EFI_SUCCESS);

    RemoveEntryList (&SockToken->TokenList);
    FreePool (SockToken);

    RemoveEntryList (&Sock->ConnectionList);

    Parent->ConnCnt--;
    DEBUG ((EFI_D_INFO, "SockWakeListenToken: accept a socket, now conncnt is %d", Parent->ConnCnt));

    Sock->Parent = NULL;
  }
}


/**
  Wake up the receive token while some data is received.

  @param  Sock                  Pointer to the socket.

**/
VOID
SockWakeRcvToken (
  IN SOCKET *Sock
  )
{
  UINT32        RcvdBytes;
  UINT32        TokenRcvdBytes;
  SOCK_TOKEN    *SockToken;
  SOCK_IO_TOKEN *RcvToken;

  ASSERT (Sock->RcvBuffer.DataQueue != NULL);

  RcvdBytes = (Sock->RcvBuffer.DataQueue)->BufSize;

  ASSERT (RcvdBytes > 0);

  while (RcvdBytes > 0 && !IsListEmpty (&Sock->RcvTokenList)) {

    SockToken = NET_LIST_HEAD (
                  &Sock->RcvTokenList,
                  SOCK_TOKEN,
                  TokenList
                  );

    RcvToken        = (SOCK_IO_TOKEN *) SockToken->Token;
    TokenRcvdBytes  = SockProcessRcvToken (Sock, RcvToken);

    if (0 == TokenRcvdBytes) {
      return ;
    }

    RemoveEntryList (&(SockToken->TokenList));
    FreePool (SockToken);
    RcvdBytes -= TokenRcvdBytes;
  }
}


/**
  Process the send token.

  @param  Sock                  Pointer to the socket.

**/
VOID
SockProcessSndToken (
  IN OUT SOCKET *Sock
  )
{
  UINT32                  FreeSpace;
  SOCK_TOKEN              *SockToken;
  UINT32                  DataLen;
  SOCK_IO_TOKEN           *SndToken;
  EFI_TCP4_TRANSMIT_DATA  *TxData;
  EFI_STATUS              Status;

  ASSERT ((Sock != NULL) && (SockStream == Sock->Type));

  FreeSpace = SockGetFreeSpace (Sock, SOCK_SND_BUF);

  //
  // to determine if process a send token using
  // socket layer flow control policy
  //
  while ((FreeSpace >= Sock->SndBuffer.LowWater) &&
         !IsListEmpty (&Sock->SndTokenList)) {

    SockToken = NET_LIST_HEAD (
                  &(Sock->SndTokenList),
                  SOCK_TOKEN,
                  TokenList
                  );

    //
    // process this token
    //
    RemoveEntryList (&(SockToken->TokenList));
    InsertTailList (
      &(Sock->ProcessingSndTokenList),
      &(SockToken->TokenList)
      );

    //
    // Proceess it in the light of  SockType
    //
    SndToken  = (SOCK_IO_TOKEN *) SockToken->Token;
    TxData    = SndToken->Packet.TxData;

    DataLen = (UINT32) TxData->DataLength;
    Status  = SockProcessTcpSndData (Sock, TxData);

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

    if (DataLen >= FreeSpace) {
      FreeSpace = 0;

    } else {
      FreeSpace -= DataLen;

    }
  }

  return ;

OnError:

  RemoveEntryList (&SockToken->TokenList);
  SIGNAL_TOKEN (SockToken->Token, Status);
  FreePool (SockToken);
}


/**
  Create a socket with initial data SockInitData.

  @param  SockInitData          Pointer to the initial data of the socket.

  @return Pointer to the newly created socket, return NULL when exception occured.

**/
SOCKET *
SockCreate (
  IN SOCK_INIT_DATA *SockInitData
  )
{
  SOCKET      *Sock;
  SOCKET      *Parent;
  EFI_STATUS  Status;

  ASSERT ((SockInitData != NULL) && (SockInitData->ProtoHandler != NULL));
  ASSERT (SockInitData->Type == SockStream);
  ASSERT ((SockInitData->ProtoData != NULL) && (SockInitData->DataSize <= PROTO_RESERVED_LEN));

  Parent = SockInitData->Parent;

  if ((Parent != NULL) && (Parent->ConnCnt == Parent->BackLog)) {
    DEBUG (
      (EFI_D_ERROR,
      "SockCreate: Socket parent has "
      "reached its connection limit with %d ConnCnt and %d BackLog\n",
      Parent->ConnCnt,
      Parent->BackLog)
      );

    return NULL;
  }

  Sock = AllocateZeroPool (sizeof (SOCKET));
  if (NULL == Sock) {

    DEBUG ((EFI_D_ERROR, "SockCreate: No resource to create a new socket\n"));
    return NULL;
  }

  InitializeListHead (&Sock->Link);
  InitializeListHead (&Sock->ConnectionList);
  InitializeListHead (&Sock->ListenTokenList);
  InitializeListHead (&Sock->RcvTokenList);
  InitializeListHead (&Sock->SndTokenList);
  InitializeListHead (&Sock->ProcessingSndTokenList);

  EfiInitializeLock (&(Sock->Lock), TPL_CALLBACK);

  Sock->SndBuffer.DataQueue = NetbufQueAlloc ();
  if (NULL == Sock->SndBuffer.DataQueue) {
    DEBUG ((EFI_D_ERROR, "SockCreate: No resource to allocate"
      " SndBuffer for new socket\n"));

    goto OnError;
  }

  Sock->RcvBuffer.DataQueue = NetbufQueAlloc ();
  if (NULL == Sock->RcvBuffer.DataQueue) {
    DEBUG ((EFI_D_ERROR, "SockCreate: No resource to allocate "
      "RcvBuffer for new socket\n"));

    goto OnError;
  }

  Sock->Signature           = SOCK_SIGNATURE;

  Sock->Parent              = Parent;
  Sock->BackLog             = SockInitData->BackLog;
  Sock->ProtoHandler        = SockInitData->ProtoHandler;
  Sock->SndBuffer.HighWater = SockInitData->SndBufferSize;
  Sock->RcvBuffer.HighWater = SockInitData->RcvBufferSize;
  Sock->Type                = SockInitData->Type;
  Sock->DriverBinding       = SockInitData->DriverBinding;
  Sock->State               = SockInitData->State;
  Sock->CreateCallback      = SockInitData->CreateCallback;
  Sock->DestroyCallback     = SockInitData->DestroyCallback;
  Sock->Context             = SockInitData->Context;

  Sock->SockError           = EFI_ABORTED;
  Sock->SndBuffer.LowWater  = SOCK_BUFF_LOW_WATER;
  Sock->RcvBuffer.LowWater  = SOCK_BUFF_LOW_WATER;

  //
  // Install protocol on Sock->SockHandle
  //
  CopyMem (
    &(Sock->NetProtocol.TcpProtocol),
    SockInitData->Protocol,
    sizeof (EFI_TCP4_PROTOCOL)
    );

  //
  // copy the protodata into socket
  //
  CopyMem (Sock->ProtoReserved, SockInitData->ProtoData, SockInitData->DataSize);

  Status = gBS->InstallMultipleProtocolInterfaces (
                  &Sock->SockHandle,
                  &gEfiTcp4ProtocolGuid,
                  &(Sock->NetProtocol.TcpProtocol),
                  NULL
                  );

  if (EFI_ERROR (Status)) {
    DEBUG ((EFI_D_ERROR, "SockCreate: Install TCP protocol in "
      "socket failed with %r\n", Status));

    goto OnError;
  }

  if (Parent != NULL) {
    ASSERT (Parent->BackLog > 0);
    ASSERT (SOCK_IS_LISTENING (Parent));

    //
    // need to add it into Parent->ConnectionList
    // if the Parent->ConnCnt < Parent->BackLog
    //
    Parent->ConnCnt++;

    DEBUG (
      (EFI_D_INFO,
      "SockCreate: Create a new socket and add to parent, now conncnt is %d\n",
      Parent->ConnCnt)
      );

    InsertTailList (&Parent->ConnectionList, &Sock->ConnectionList);
  }

  if (Sock->CreateCallback != NULL) {
    Status = Sock->CreateCallback (Sock, Sock->Context);
    if (EFI_ERROR (Status)) {
      goto OnError;
    }
  }

  return Sock;

OnError:

  if (Sock->SockHandle != NULL) {
    gBS->UninstallMultipleProtocolInterfaces (
           Sock->SockHandle,
           &gEfiTcp4ProtocolGuid,
           &(Sock->NetProtocol.TcpProtocol),
           NULL
           );
  }

  if (NULL != Sock->SndBuffer.DataQueue) {
    NetbufQueFree (Sock->SndBuffer.DataQueue);
  }

  if (NULL != Sock->RcvBuffer.DataQueue) {
    NetbufQueFree (Sock->RcvBuffer.DataQueue);
  }

  FreePool (Sock);

  return NULL;
}


/**
  Destroy a socket.

  @param  Sock                  Pointer to the socket.

**/
VOID
SockDestroy (
  IN OUT SOCKET *Sock
  )
{
  VOID        *SockProtocol;
  EFI_GUID    *ProtocolGuid;
  EFI_STATUS  Status;

  ASSERT (SockStream == Sock->Type);

  if (Sock->DestroyCallback != NULL) {
    Sock->DestroyCallback (Sock, Sock->Context);
  }

  //
  // Flush the completion token buffered
  // by sock and rcv, snd buffer
  //
  if (!SOCK_IS_UNCONFIGURED (Sock)) {

    SockConnFlush (Sock);
    SockSetState (Sock, SO_CLOSED);
    Sock->ConfigureState = SO_UNCONFIGURED;

  }
  //
  // Destory the RcvBuffer Queue and SendBuffer Queue
  //
  NetbufQueFree (Sock->RcvBuffer.DataQueue);
  NetbufQueFree (Sock->SndBuffer.DataQueue);

  //
  // Remove it from parent connection list if needed
  //
  if (Sock->Parent != NULL) {

    RemoveEntryList (&(Sock->ConnectionList));
    (Sock->Parent->ConnCnt)--;

    DEBUG (
      (EFI_D_INFO,
      "SockDestory: Delete a unaccepted socket from parent"
      "now conncnt is %d\n",
      Sock->Parent->ConnCnt)
      );

    Sock->Parent = NULL;
  }

  //
  // Set the protocol guid and driver binding handle
  // in the light of Sock->SockType
  //
  ProtocolGuid = &gEfiTcp4ProtocolGuid;

  //
  // Retrieve the protocol installed on this sock
  //
  Status = gBS->OpenProtocol (
                  Sock->SockHandle,
                  ProtocolGuid,
                  &SockProtocol,
                  Sock->DriverBinding,
                  Sock->SockHandle,
                  EFI_OPEN_PROTOCOL_GET_PROTOCOL
                  );

  if (EFI_ERROR (Status)) {

    DEBUG ((EFI_D_ERROR, "SockDestroy: Open protocol installed "
      "on socket failed with %r\n", Status));

    goto FreeSock;
  }

  //
  // Uninstall the protocol installed on this sock
  // in the light of Sock->SockType
  //
  gBS->UninstallMultipleProtocolInterfaces (
        Sock->SockHandle,
        ProtocolGuid,
        SockProtocol,
        NULL
        );

FreeSock:
  FreePool (Sock);
  return ;
}


/**
  Flush the sndBuffer and rcvBuffer of socket.

  @param  Sock                  Pointer to the socket.

**/
VOID
SockConnFlush (
  IN OUT SOCKET *Sock
  )
{
  SOCKET  *Child;

  ASSERT (Sock != NULL);

  //
  // Clear the flag in this socket
  //
  Sock->Flag = 0;

  //
  // Flush the SndBuffer and RcvBuffer of Sock
  //
  NetbufQueFlush (Sock->SndBuffer.DataQueue);
  NetbufQueFlush (Sock->RcvBuffer.DataQueue);

  //
  // Signal the pending token
  //
  if (Sock->ConnectionToken != NULL) {
    SIGNAL_TOKEN (Sock->ConnectionToken, Sock->SockError);
    Sock->ConnectionToken = NULL;
  }

  if (Sock->CloseToken != NULL) {
    SIGNAL_TOKEN (Sock->CloseToken, Sock->SockError);
    Sock->CloseToken = NULL;
  }

  SockFlushPendingToken (Sock, &(Sock->ListenTokenList));
  SockFlushPendingToken (Sock, &(Sock->RcvTokenList));
  SockFlushPendingToken (Sock, &(Sock->SndTokenList));
  SockFlushPendingToken (Sock, &(Sock->ProcessingSndTokenList));

  //
  // Destroy the pending connection, if it is a listening socket
  //
  if (SOCK_IS_LISTENING (Sock)) {
    while (!IsListEmpty (&Sock->ConnectionList)) {
      Child = NET_LIST_HEAD (
                &Sock->ConnectionList,
                SOCKET,
                ConnectionList
                );

      SockDestroyChild (Child);
    }

    Sock->ConnCnt = 0;
  }

  return ;
}


/**
  Set the state of the socket.

  @param  Sock                  Pointer to the socket.
  @param  State                 The new socket state to be set.

**/
VOID
SockSetState (
  IN OUT SOCKET     *Sock,
  IN     UINT8      State
  )
{
  Sock->State = State;
}


/**
  Clone a new socket including its associated protocol control block.

  @param  Sock                  Pointer to the socket to be cloned.

  @return Pointer to the newly cloned socket. If NULL, error condition occurred.

**/
SOCKET *
SockClone (
  IN SOCKET *Sock
  )
{
  SOCKET          *ClonedSock;
  SOCK_INIT_DATA  InitData;

  InitData.BackLog         = Sock->BackLog;
  InitData.Parent          = Sock;
  InitData.State           = Sock->State;
  InitData.ProtoHandler    = Sock->ProtoHandler;
  InitData.Type            = Sock->Type;
  InitData.RcvBufferSize   = Sock->RcvBuffer.HighWater;
  InitData.SndBufferSize   = Sock->SndBuffer.HighWater;
  InitData.DriverBinding   = Sock->DriverBinding;
  InitData.Protocol        = &(Sock->NetProtocol);
  InitData.CreateCallback  = Sock->CreateCallback;
  InitData.DestroyCallback = Sock->DestroyCallback;
  InitData.Context         = Sock->Context;
  InitData.ProtoData       = Sock->ProtoReserved;
  InitData.DataSize        = sizeof (Sock->ProtoReserved);

  ClonedSock               = SockCreate (&InitData);

  if (NULL == ClonedSock) {
    DEBUG ((EFI_D_ERROR, "SockClone: no resource to create a cloned sock\n"));
    return NULL;
  }

  SockSetState (ClonedSock, SO_CONNECTING);
  ClonedSock->ConfigureState = Sock->ConfigureState;

  return ClonedSock;
}


/**
  Called by the low layer protocol to indicate the socket a connection is 
  established. 
  
  This function just changes the socket's state to SO_CONNECTED 
  and signals the token used for connection establishment.

  @param  Sock                  Pointer to the socket associated with the
                                established connection.
**/
VOID
SockConnEstablished (
  IN SOCKET *Sock
  )
{

  ASSERT (SO_CONNECTING == Sock->State);

  SockSetState (Sock, SO_CONNECTED);

  if (NULL == Sock->Parent) {
    SockWakeConnToken (Sock);
  } else {
    SockWakeListenToken (Sock);
  }

  return ;
}


/**
  Called by the low layer protocol to indicate the connection is closed.
  
  This function flushes the socket, sets the state to SO_CLOSED and signals 
  the close token.

  @param  Sock                  Pointer to the socket associated with the closed
                                connection.
                                
**/
VOID
SockConnClosed (
  IN OUT SOCKET *Sock
  )
{
  if (Sock->CloseToken != NULL) {
    SIGNAL_TOKEN (Sock->CloseToken, EFI_SUCCESS);
    Sock->CloseToken = NULL;
  }

  SockConnFlush (Sock);
  SockSetState (Sock, SO_CLOSED);

  if (Sock->Parent != NULL) {
    SockDestroyChild (Sock);
  }

}


/**
  Called by low layer protocol to indicate that some data is sent or processed.
   
  This function trims the sent data in the socket send buffer, signals the data 
  token if proper.

  @param  Sock                  Pointer to the socket.
  @param  Count                 The length of the data processed or sent, in bytes.

**/
VOID
SockDataSent (
  IN SOCKET     *Sock,
  IN UINT32     Count
  )
{
  SOCK_TOKEN            *SockToken;
  SOCK_COMPLETION_TOKEN *SndToken;

  ASSERT (!IsListEmpty (&Sock->ProcessingSndTokenList));
  ASSERT (Count <= (Sock->SndBuffer.DataQueue)->BufSize);

  NetbufQueTrim (Sock->SndBuffer.DataQueue, Count);

  //
  // To check if we can signal some snd token in this socket
  //
  while (Count > 0) {
    SockToken = NET_LIST_HEAD (
                  &(Sock->ProcessingSndTokenList),
                  SOCK_TOKEN,
                  TokenList
                  );

    SndToken = SockToken->Token;

    if (SockToken->RemainDataLen <= Count) {

      RemoveEntryList (&(SockToken->TokenList));
      SIGNAL_TOKEN (SndToken, EFI_SUCCESS);
      Count -= SockToken->RemainDataLen;
      FreePool (SockToken);
    } else {

      SockToken->RemainDataLen -= Count;
      Count = 0;
    }
  }

  //
  // to judge if we can process some send token in
  // Sock->SndTokenList, if so process those send token
  //
  SockProcessSndToken (Sock);
  return ;
}


/**
  Called by the low layer protocol to copy some data in socket send
  buffer starting from the specific offset to a buffer provided by
  the caller.

  @param  Sock                  Pointer to the socket.
  @param  Offset                The start point of the data to be copied.
  @param  Len                   The length of the data to be copied.
  @param  Dest                  Pointer to the destination to copy the data.

  @return The data size copied.

**/
UINT32
SockGetDataToSend (
  IN SOCKET      *Sock,
  IN UINT32      Offset,
  IN UINT32      Len,
  IN UINT8       *Dest
  )
{
  ASSERT ((Sock != NULL) && SockStream == Sock->Type);

  return NetbufQueCopy (
          Sock->SndBuffer.DataQueue,
          Offset,
          Len,
          Dest
          );
}


/**
  Called by the low layer protocol to deliver received data to socket layer.
  
  This function will append the data to the socket receive buffer, set ther 
  urgent data length and then check if any receive token can be signaled.

  @param  Sock                  Pointer to the socket.
  @param  NetBuffer             Pointer to the buffer that contains the received
                                data.
  @param  UrgLen                The length of the urgent data in the received data.

**/
VOID
SockDataRcvd (
  IN     SOCKET    *Sock,
  IN OUT NET_BUF   *NetBuffer,
  IN     UINT32    UrgLen
  )
{
  ASSERT ((Sock != NULL) && (Sock->RcvBuffer.DataQueue != NULL) &&
    UrgLen <= NetBuffer->TotalSize);

  NET_GET_REF (NetBuffer);

  ((TCP_RSV_DATA *) (NetBuffer->ProtoData))->UrgLen = UrgLen;

  NetbufQueAppend (Sock->RcvBuffer.DataQueue, NetBuffer);

  SockWakeRcvToken (Sock);
  return ;
}


/**
  Get the length of the free space of the specific socket buffer.

  @param  Sock                  Pointer to the socket.
  @param  Which                 Flag to indicate which socket buffer to check,
                                either send buffer or receive buffer.

  @return The length of the free space, in bytes.

**/
UINT32
SockGetFreeSpace (
  IN SOCKET  *Sock,
  IN UINT32  Which
  )
{
  UINT32      BufferCC;
  SOCK_BUFFER *SockBuffer;

  ASSERT ((Sock != NULL) && ((SOCK_SND_BUF == Which) || (SOCK_RCV_BUF == Which)));

  if (SOCK_SND_BUF == Which) {
    SockBuffer = &(Sock->SndBuffer);
  } else {
    SockBuffer = &(Sock->RcvBuffer);
  }

  BufferCC = (SockBuffer->DataQueue)->BufSize;

  if (BufferCC >= SockBuffer->HighWater) {

    return 0;
  }

  return SockBuffer->HighWater - BufferCC;
}


/**
  Signal the receive token with the specific error or
  set socket error code after error is received.

  @param  Sock                  Pointer to the socket.
  @param  Error                 The error code received.

**/
VOID
SockRcvdErr (
  IN OUT SOCKET       *Sock,
  IN     EFI_STATUS   Error
  )
{
  SOCK_TOKEN  *SockToken;

  if (!IsListEmpty (&Sock->RcvTokenList)) {

    SockToken = NET_LIST_HEAD (
                  &Sock->RcvTokenList,
                  SOCK_TOKEN,
                  TokenList
                  );

    RemoveEntryList (&SockToken->TokenList);

    SIGNAL_TOKEN (SockToken->Token, Error);

    FreePool (SockToken);
  } else {

    SOCK_ERROR (Sock, Error);
  }
}


/**
  Called by the low layer protocol to indicate that there will be no more data 
  from the communication peer.
  
  This function set the socket's state to SO_NO_MORE_DATA and signal all queued 
  IO tokens with the error status EFI_CONNECTION_FIN.

  @param  Sock                  Pointer to the socket.

**/
VOID
SockNoMoreData (
  IN OUT SOCKET *Sock
  )
{
  EFI_STATUS  Err;

  SOCK_NO_MORE_DATA (Sock);

  if (!IsListEmpty (&Sock->RcvTokenList)) {

    ASSERT (0 == GET_RCV_DATASIZE (Sock));

    Err = Sock->SockError;

    SOCK_ERROR (Sock, EFI_CONNECTION_FIN);

    SockFlushPendingToken (Sock, &Sock->RcvTokenList);

    SOCK_ERROR (Sock, Err);

  }

}


/**
  Get the first buffer block in the specific socket buffer.

  @param  Sockbuf               Pointer to the socket buffer.

  @return Pointer to the first buffer in the queue. NULL if the queue is empty.

**/
NET_BUF *
SockBufFirst (
  IN SOCK_BUFFER *Sockbuf
  )
{
  LIST_ENTRY      *NetbufList;

  NetbufList = &(Sockbuf->DataQueue->BufList);

  if (IsListEmpty (NetbufList)) {
    return NULL;
  }

  return NET_LIST_HEAD (NetbufList, NET_BUF, List);
}


/**
  Get the next buffer block in the specific socket buffer.

  @param  Sockbuf               Pointer to the socket buffer.
  @param  SockEntry             Pointer to the buffer block prior to the required
                                one.

  @return Pointer to the buffer block next to SockEntry. NULL if SockEntry is 
          the tail or head entry.

**/
NET_BUF *
SockBufNext (
  IN SOCK_BUFFER *Sockbuf,
  IN NET_BUF     *SockEntry
  )
{
  LIST_ENTRY      *NetbufList;

  NetbufList = &(Sockbuf->DataQueue->BufList);

  if ((SockEntry->List.ForwardLink == NetbufList) ||
      (SockEntry->List.BackLink == &SockEntry->List) ||
      (SockEntry->List.ForwardLink == &SockEntry->List)) {

    return NULL;
  }

  return NET_LIST_USER_STRUCT (SockEntry->List.ForwardLink, NET_BUF, List);
}