MnpIo.c

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#include "MnpImpl.h"
#include "MnpVlan.h"
 
BOOLEAN
MnpIsValidTxToken (
  IN MNP_INSTANCE_DATA                     *Instance,
  IN EFI_MANAGED_NETWORK_COMPLETION_TOKEN  *Token
  )
{
  MNP_SERVICE_DATA                   *MnpServiceData;
  EFI_MANAGED_NETWORK_TRANSMIT_DATA  *TxData;
  UINT32                             Index;
  UINT32                             TotalLength;
  EFI_MANAGED_NETWORK_FRAGMENT_DATA  *FragmentTable;
 
  MnpServiceData = Instance->MnpServiceData;
  NET_CHECK_SIGNATURE (MnpServiceData, MNP_SERVICE_DATA_SIGNATURE);
 
  TxData = Token->Packet.TxData;
 
  if ((Token->Event == NULL) || (TxData == NULL) || (TxData->FragmentCount == 0)) {
    //
    // The token is invalid if the Event is NULL, or the TxData is NULL, or
    // the fragment count is zero.
    //
    DEBUG ((DEBUG_WARN, "MnpIsValidTxToken: Invalid Token.\n"));
    return FALSE;
  }
 
  if ((TxData->DestinationAddress != NULL) && (TxData->HeaderLength != 0)) {
    //
    // The token is invalid if the HeaderLength isn't zero while the DestinationAddress
    // is NULL (The destination address is already put into the packet).
    //
    DEBUG ((DEBUG_WARN, "MnpIsValidTxToken: DestinationAddress isn't NULL, HeaderLength must be 0.\n"));
    return FALSE;
  }
 
  TotalLength   = 0;
  FragmentTable = TxData->FragmentTable;
  for (Index = 0; Index < TxData->FragmentCount; Index++) {
    if ((FragmentTable[Index].FragmentLength == 0) || (FragmentTable[Index].FragmentBuffer == NULL)) {
      //
      // The token is invalid if any FragmentLength is zero or any FragmentBuffer is NULL.
      //
      DEBUG ((DEBUG_WARN, "MnpIsValidTxToken: Invalid FragmentLength or FragmentBuffer.\n"));
      return FALSE;
    }
 
    TotalLength += FragmentTable[Index].FragmentLength;
  }
 
  if ((TxData->DestinationAddress == NULL) && (FragmentTable[0].FragmentLength < TxData->HeaderLength)) {
    //
    // Media header is split between fragments.
    //
    return FALSE;
  }
 
  if (TotalLength != (TxData->DataLength + TxData->HeaderLength)) {
    //
    // The length calculated from the fragment information doesn't equal to the
    // sum of the DataLength and the HeaderLength.
    //
    DEBUG ((DEBUG_WARN, "MnpIsValidTxData: Invalid Datalength compared with the sum of fragment length.\n"));
    return FALSE;
  }
 
  if (TxData->DataLength > MnpServiceData->Mtu) {
    //
    // The total length is larger than the MTU.
    //
    DEBUG ((DEBUG_WARN, "MnpIsValidTxData: TxData->DataLength exceeds Mtu.\n"));
    return FALSE;
  }
 
  return TRUE;
}
 
EFI_STATUS
MnpBuildTxPacket (
  IN     MNP_SERVICE_DATA                   *MnpServiceData,
  IN     EFI_MANAGED_NETWORK_TRANSMIT_DATA  *TxData,
  OUT UINT8                                 **PktBuf,
  OUT UINT32                                *PktLen
  )
{
  EFI_SIMPLE_NETWORK_MODE  *SnpMode;
  UINT8                    *DstPos;
  UINT16                   Index;
  MNP_DEVICE_DATA          *MnpDeviceData;
  UINT8                    *TxBuf;
 
  MnpDeviceData = MnpServiceData->MnpDeviceData;
 
  TxBuf = MnpAllocTxBuf (MnpDeviceData);
  if (TxBuf == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }
 
  //
  // Reserve space for vlan tag if needed.
  //
  if (MnpServiceData->VlanId != 0) {
    *PktBuf = TxBuf + NET_VLAN_TAG_LEN;
  } else {
    *PktBuf = TxBuf;
  }
 
  if ((TxData->DestinationAddress == NULL) && (TxData->FragmentCount == 1)) {
    CopyMem (
      *PktBuf,
      TxData->FragmentTable[0].FragmentBuffer,
      TxData->FragmentTable[0].FragmentLength
      );
 
    *PktLen = TxData->FragmentTable[0].FragmentLength;
  } else {
    //
    // Either media header isn't in FragmentTable or there is more than
    // one fragment, copy the data into the packet buffer. Reserve the
    // media header space if necessary.
    //
    SnpMode = MnpDeviceData->Snp->Mode;
    DstPos  = *PktBuf;
    *PktLen = 0;
    if (TxData->DestinationAddress != NULL) {
      //
      // If dest address is not NULL, move DstPos to reserve space for the
      // media header. Add the media header length to buflen.
      //
      DstPos  += SnpMode->MediaHeaderSize;
      *PktLen += SnpMode->MediaHeaderSize;
    }
 
    for (Index = 0; Index < TxData->FragmentCount; Index++) {
      //
      // Copy the data.
      //
      CopyMem (
        DstPos,
        TxData->FragmentTable[Index].FragmentBuffer,
        TxData->FragmentTable[Index].FragmentLength
        );
      DstPos += TxData->FragmentTable[Index].FragmentLength;
    }
 
    //
    // Set the buffer length.
    //
    *PktLen += TxData->DataLength + TxData->HeaderLength;
  }
 
  return EFI_SUCCESS;
}
 
EFI_STATUS
MnpSyncSendPacket (
  IN     MNP_SERVICE_DATA                      *MnpServiceData,
  IN     UINT8                                 *Packet,
  IN     UINT32                                Length,
  IN OUT EFI_MANAGED_NETWORK_COMPLETION_TOKEN  *Token
  )
{
  EFI_STATUS                         Status;
  EFI_SIMPLE_NETWORK_PROTOCOL        *Snp;
  EFI_MANAGED_NETWORK_TRANSMIT_DATA  *TxData;
  UINT32                             HeaderSize;
  MNP_DEVICE_DATA                    *MnpDeviceData;
  UINT16                             ProtocolType;
 
  MnpDeviceData = MnpServiceData->MnpDeviceData;
  Snp           = MnpDeviceData->Snp;
  TxData        = Token->Packet.TxData;
  Token->Status = EFI_SUCCESS;
  HeaderSize    = Snp->Mode->MediaHeaderSize - TxData->HeaderLength;
 
  //
  // Check media status before transmit packet.
  // Note: media status will be updated by periodic timer MediaDetectTimer.
  //
  if (Snp->Mode->MediaPresentSupported && !Snp->Mode->MediaPresent) {
    //
    // Media not present, skip packet transmit and report EFI_NO_MEDIA
    //
    DEBUG ((DEBUG_WARN, "MnpSyncSendPacket: No network cable detected.\n"));
    Token->Status = EFI_NO_MEDIA;
    goto SIGNAL_TOKEN;
  }
 
  if (MnpServiceData->VlanId != 0) {
    //
    // Insert VLAN tag
    //
    MnpInsertVlanTag (MnpServiceData, TxData, &ProtocolType, &Packet, &Length);
  } else {
    ProtocolType = TxData->ProtocolType;
  }
 
  //
  // Transmit the packet through SNP.
  //
  Status = Snp->Transmit (
                  Snp,
                  HeaderSize,
                  Length,
                  Packet,
                  TxData->SourceAddress,
                  TxData->DestinationAddress,
                  &ProtocolType
                  );
  if (Status == EFI_NOT_READY) {
    Status = MnpRecycleTxBuf (MnpDeviceData);
    if (EFI_ERROR (Status)) {
      Token->Status = EFI_DEVICE_ERROR;
      goto SIGNAL_TOKEN;
    }
 
    Status = Snp->Transmit (
                    Snp,
                    HeaderSize,
                    Length,
                    Packet,
                    TxData->SourceAddress,
                    TxData->DestinationAddress,
                    &ProtocolType
                    );
  }
 
  if (EFI_ERROR (Status)) {
    Token->Status = EFI_DEVICE_ERROR;
  }
 
SIGNAL_TOKEN:
 
  gBS->SignalEvent (Token->Event);
 
  //
  // Dispatch the DPC queued by the NotifyFunction of Token->Event.
  //
  DispatchDpc ();
 
  return EFI_SUCCESS;
}
 
EFI_STATUS
MnpInstanceDeliverPacket (
  IN OUT MNP_INSTANCE_DATA  *Instance
  )
{
  MNP_DEVICE_DATA                       *MnpDeviceData;
  MNP_RXDATA_WRAP                       *RxDataWrap;
  NET_BUF                               *DupNbuf;
  EFI_MANAGED_NETWORK_RECEIVE_DATA      *RxData;
  EFI_SIMPLE_NETWORK_MODE               *SnpMode;
  EFI_MANAGED_NETWORK_COMPLETION_TOKEN  *RxToken;
 
  MnpDeviceData = Instance->MnpServiceData->MnpDeviceData;
  NET_CHECK_SIGNATURE (MnpDeviceData, MNP_DEVICE_DATA_SIGNATURE);
 
  if (NetMapIsEmpty (&Instance->RxTokenMap) || IsListEmpty (&Instance->RcvdPacketQueue)) {
    //
    // No pending received data or no available receive token, return.
    //
    return EFI_SUCCESS;
  }
 
  ASSERT (Instance->RcvdPacketQueueSize != 0);
 
  RxDataWrap = NET_LIST_HEAD (&Instance->RcvdPacketQueue, MNP_RXDATA_WRAP, WrapEntry);
  if (RxDataWrap->Nbuf->RefCnt > 2) {
    //
    // There are other instances share this Nbuf, duplicate to get a
    // copy to allow the instance to do R/W operations.
    //
    DupNbuf = MnpAllocNbuf (MnpDeviceData);
    if (DupNbuf == NULL) {
      DEBUG ((DEBUG_WARN, "MnpDeliverPacket: Failed to allocate a free Nbuf.\n"));
 
      return EFI_OUT_OF_RESOURCES;
    }
 
    //
    // Duplicate the net buffer.
    //
    NetbufDuplicate (RxDataWrap->Nbuf, DupNbuf, 0);
    MnpFreeNbuf (MnpDeviceData, RxDataWrap->Nbuf);
    RxDataWrap->Nbuf = DupNbuf;
  }
 
  //
  // All resources are OK, remove the packet from the queue.
  //
  NetListRemoveHead (&Instance->RcvdPacketQueue);
  Instance->RcvdPacketQueueSize--;
 
  RxData  = &RxDataWrap->RxData;
  SnpMode = MnpDeviceData->Snp->Mode;
 
  //
  // Set all the buffer pointers.
  //
  RxData->MediaHeader        = NetbufGetByte (RxDataWrap->Nbuf, 0, NULL);
  RxData->DestinationAddress = RxData->MediaHeader;
  RxData->SourceAddress      = (UINT8 *)RxData->MediaHeader + SnpMode->HwAddressSize;
  RxData->PacketData         = (UINT8 *)RxData->MediaHeader + SnpMode->MediaHeaderSize;
 
  //
  // Insert this RxDataWrap into the delivered queue.
  //
  InsertTailList (&Instance->RxDeliveredPacketQueue, &RxDataWrap->WrapEntry);
 
  //
  // Get the receive token from the RxTokenMap.
  //
  RxToken = NetMapRemoveHead (&Instance->RxTokenMap, NULL);
 
  //
  // Signal this token's event.
  //
  RxToken->Packet.RxData = &RxDataWrap->RxData;
  RxToken->Status        = EFI_SUCCESS;
  gBS->SignalEvent (RxToken->Event);
 
  return EFI_SUCCESS;
}
 
VOID
MnpDeliverPacket (
  IN MNP_SERVICE_DATA  *MnpServiceData
  )
{
  LIST_ENTRY         *Entry;
  MNP_INSTANCE_DATA  *Instance;
 
  NET_CHECK_SIGNATURE (MnpServiceData, MNP_SERVICE_DATA_SIGNATURE);
 
  NET_LIST_FOR_EACH (Entry, &MnpServiceData->ChildrenList) {
    Instance = NET_LIST_USER_STRUCT (Entry, MNP_INSTANCE_DATA, InstEntry);
    NET_CHECK_SIGNATURE (Instance, MNP_INSTANCE_DATA_SIGNATURE);
 
    //
    // Try to deliver packet for this instance.
    //
    MnpInstanceDeliverPacket (Instance);
  }
}
 
VOID
EFIAPI
MnpRecycleRxData (
  IN EFI_EVENT  Event,
  IN VOID       *Context
  )
{
  MNP_RXDATA_WRAP  *RxDataWrap;
  MNP_DEVICE_DATA  *MnpDeviceData;
 
  ASSERT (Context != NULL);
 
  RxDataWrap = (MNP_RXDATA_WRAP *)Context;
  NET_CHECK_SIGNATURE (RxDataWrap->Instance, MNP_INSTANCE_DATA_SIGNATURE);
 
  ASSERT (RxDataWrap->Nbuf != NULL);
 
  MnpDeviceData = RxDataWrap->Instance->MnpServiceData->MnpDeviceData;
  NET_CHECK_SIGNATURE (MnpDeviceData, MNP_DEVICE_DATA_SIGNATURE);
 
  //
  // Free this Nbuf.
  //
  MnpFreeNbuf (MnpDeviceData, RxDataWrap->Nbuf);
  RxDataWrap->Nbuf = NULL;
 
  //
  // Close the recycle event.
  //
  gBS->CloseEvent (RxDataWrap->RxData.RecycleEvent);
 
  //
  // Remove this Wrap entry from the list.
  //
  RemoveEntryList (&RxDataWrap->WrapEntry);
 
  FreePool (RxDataWrap);
}
 
VOID
MnpQueueRcvdPacket (
  IN OUT MNP_INSTANCE_DATA  *Instance,
  IN OUT MNP_RXDATA_WRAP    *RxDataWrap
  )
{
  MNP_RXDATA_WRAP  *OldRxDataWrap;
 
  NET_CHECK_SIGNATURE (Instance, MNP_INSTANCE_DATA_SIGNATURE);
 
  //
  // Check the queue size. If it exceeds the limit, drop one packet
  // from the head.
  //
  if (Instance->RcvdPacketQueueSize == MNP_MAX_RCVD_PACKET_QUE_SIZE) {
    DEBUG ((DEBUG_WARN, "MnpQueueRcvdPacket: Drop one packet bcz queue size limit reached.\n"));
 
    //
    // Get the oldest packet.
    //
    OldRxDataWrap = NET_LIST_HEAD (
                      &Instance->RcvdPacketQueue,
                      MNP_RXDATA_WRAP,
                      WrapEntry
                      );
 
    //
    // Recycle this OldRxDataWrap, this entry will be removed by the callee.
    //
    MnpRecycleRxData (NULL, (VOID *)OldRxDataWrap);
    Instance->RcvdPacketQueueSize--;
  }
 
  //
  // Update the timeout tick using the configured parameter.
  //
  RxDataWrap->TimeoutTick = Instance->ConfigData.ReceivedQueueTimeoutValue;
 
  //
  // Insert this Wrap into the instance queue.
  //
  InsertTailList (&Instance->RcvdPacketQueue, &RxDataWrap->WrapEntry);
  Instance->RcvdPacketQueueSize++;
}
 
BOOLEAN
MnpMatchPacket (
  IN MNP_INSTANCE_DATA                 *Instance,
  IN EFI_MANAGED_NETWORK_RECEIVE_DATA  *RxData,
  IN MNP_GROUP_ADDRESS                 *GroupAddress OPTIONAL,
  IN UINT8                             PktAttr
  )
{
  EFI_MANAGED_NETWORK_CONFIG_DATA  *ConfigData;
  LIST_ENTRY                       *Entry;
  MNP_GROUP_CONTROL_BLOCK          *GroupCtrlBlk;
 
  NET_CHECK_SIGNATURE (Instance, MNP_INSTANCE_DATA_SIGNATURE);
 
  ConfigData = &Instance->ConfigData;
 
  //
  // Check the protocol type.
  //
  if ((ConfigData->ProtocolTypeFilter != 0) && (ConfigData->ProtocolTypeFilter != RxData->ProtocolType)) {
    return FALSE;
  }
 
  if (ConfigData->EnablePromiscuousReceive) {
    //
    // Always match if this instance is configured to be promiscuous.
    //
    return TRUE;
  }
 
  //
  // The protocol type is matched, check receive filter, include unicast and broadcast.
  //
  if ((Instance->ReceiveFilter & PktAttr) != 0) {
    return TRUE;
  }
 
  //
  // Check multicast addresses.
  //
  if (ConfigData->EnableMulticastReceive && RxData->MulticastFlag) {
    ASSERT (GroupAddress != NULL);
 
    NET_LIST_FOR_EACH (Entry, &Instance->GroupCtrlBlkList) {
      GroupCtrlBlk = NET_LIST_USER_STRUCT (Entry, MNP_GROUP_CONTROL_BLOCK, CtrlBlkEntry);
      if (GroupCtrlBlk->GroupAddress == GroupAddress) {
        //
        // The instance is configured to receiveing packets destinated to this
        // multicast address.
        //
        return TRUE;
      }
    }
  }
 
  //
  // No match.
  //
  return FALSE;
}
 
VOID
MnpAnalysePacket (
  IN     MNP_SERVICE_DATA                  *MnpServiceData,
  IN     NET_BUF                           *Nbuf,
  IN OUT EFI_MANAGED_NETWORK_RECEIVE_DATA  *RxData,
  OUT MNP_GROUP_ADDRESS                    **GroupAddress,
  OUT UINT8                                *PktAttr
  )
{
  EFI_SIMPLE_NETWORK_MODE  *SnpMode;
  MNP_DEVICE_DATA          *MnpDeviceData;
  UINT8                    *BufPtr;
  LIST_ENTRY               *Entry;
 
  MnpDeviceData = MnpServiceData->MnpDeviceData;
  SnpMode       = MnpDeviceData->Snp->Mode;
 
  //
  // Get the packet buffer.
  //
  BufPtr = NetbufGetByte (Nbuf, 0, NULL);
  ASSERT (BufPtr != NULL);
 
  //
  // Set the initial values.
  //
  RxData->BroadcastFlag   = FALSE;
  RxData->MulticastFlag   = FALSE;
  RxData->PromiscuousFlag = FALSE;
  *PktAttr                = UNICAST_PACKET;
 
  if (!NET_MAC_EQUAL (&SnpMode->CurrentAddress, BufPtr, SnpMode->HwAddressSize)) {
    //
    // This packet isn't destinated to our current mac address, it't not unicast.
    //
    *PktAttr = 0;
 
    if (NET_MAC_EQUAL (&SnpMode->BroadcastAddress, BufPtr, SnpMode->HwAddressSize)) {
      //
      // It's broadcast.
      //
      RxData->BroadcastFlag = TRUE;
      *PktAttr              = BROADCAST_PACKET;
    } else if ((*BufPtr & 0x01) == 0x1) {
      //
      // It's multicast, try to match the multicast filters.
      //
      NET_LIST_FOR_EACH (Entry, &MnpDeviceData->GroupAddressList) {
        *GroupAddress = NET_LIST_USER_STRUCT (Entry, MNP_GROUP_ADDRESS, AddrEntry);
        if (NET_MAC_EQUAL (BufPtr, &((*GroupAddress)->Address), SnpMode->HwAddressSize)) {
          RxData->MulticastFlag = TRUE;
          break;
        }
      }
 
      if (!RxData->MulticastFlag) {
        //
        // No match, set GroupAddress to NULL. This multicast packet must
        // be the result of PROMISUCOUS or PROMISUCOUS_MULTICAST flag is on.
        //
        *GroupAddress           = NULL;
        RxData->PromiscuousFlag = TRUE;
 
        if (MnpDeviceData->PromiscuousCount == 0) {
          //
          // Skip the below code, there is no receiver of this packet.
          //
          return;
        }
      }
    } else {
      RxData->PromiscuousFlag = TRUE;
    }
  }
 
  ZeroMem (&RxData->Timestamp, sizeof (EFI_TIME));
 
  //
  // Fill the common parts of RxData.
  //
  RxData->PacketLength  = Nbuf->TotalSize;
  RxData->HeaderLength  = SnpMode->MediaHeaderSize;
  RxData->AddressLength = SnpMode->HwAddressSize;
  RxData->DataLength    = RxData->PacketLength - RxData->HeaderLength;
  RxData->ProtocolType  = NTOHS (*(UINT16 *)(BufPtr + 2 * SnpMode->HwAddressSize));
}
 
MNP_RXDATA_WRAP *
MnpWrapRxData (
  IN MNP_INSTANCE_DATA                 *Instance,
  IN EFI_MANAGED_NETWORK_RECEIVE_DATA  *RxData
  )
{
  EFI_STATUS       Status;
  MNP_RXDATA_WRAP  *RxDataWrap;
 
  //
  // Allocate memory.
  //
  RxDataWrap = AllocatePool (sizeof (MNP_RXDATA_WRAP));
  if (RxDataWrap == NULL) {
    DEBUG ((DEBUG_ERROR, "MnpDispatchPacket: Failed to allocate a MNP_RXDATA_WRAP.\n"));
    return NULL;
  }
 
  RxDataWrap->Instance = Instance;
 
  //
  // Fill the RxData in RxDataWrap,
  //
  CopyMem (&RxDataWrap->RxData, RxData, sizeof (RxDataWrap->RxData));
 
  //
  // Create the recycle event.
  //
  Status = gBS->CreateEvent (
                  EVT_NOTIFY_SIGNAL,
                  TPL_NOTIFY,
                  MnpRecycleRxData,
                  RxDataWrap,
                  &RxDataWrap->RxData.RecycleEvent
                  );
  if (EFI_ERROR (Status)) {
    DEBUG ((DEBUG_ERROR, "MnpDispatchPacket: gBS->CreateEvent failed, %r.\n", Status));
 
    FreePool (RxDataWrap);
    return NULL;
  }
 
  return RxDataWrap;
}
 
VOID
MnpEnqueuePacket (
  IN MNP_SERVICE_DATA  *MnpServiceData,
  IN NET_BUF           *Nbuf
  )
{
  LIST_ENTRY                        *Entry;
  MNP_INSTANCE_DATA                 *Instance;
  EFI_MANAGED_NETWORK_RECEIVE_DATA  RxData;
  UINT8                             PktAttr;
  MNP_GROUP_ADDRESS                 *GroupAddress;
  MNP_RXDATA_WRAP                   *RxDataWrap;
 
  GroupAddress = NULL;
  //
  // First, analyse the packet header.
  //
  MnpAnalysePacket (MnpServiceData, Nbuf, &RxData, &GroupAddress, &PktAttr);
 
  if (RxData.PromiscuousFlag && (MnpServiceData->MnpDeviceData->PromiscuousCount == 0)) {
    //
    // No receivers, no more action need.
    //
    return;
  }
 
  //
  // Iterate the children to find match.
  //
  NET_LIST_FOR_EACH (Entry, &MnpServiceData->ChildrenList) {
    Instance = NET_LIST_USER_STRUCT (Entry, MNP_INSTANCE_DATA, InstEntry);
    NET_CHECK_SIGNATURE (Instance, MNP_INSTANCE_DATA_SIGNATURE);
 
    if (!Instance->Configured) {
      continue;
    }
 
    //
    // Check the packet against the instance receive filters.
    //
    if (MnpMatchPacket (Instance, &RxData, GroupAddress, PktAttr)) {
      //
      // Wrap the RxData.
      //
      RxDataWrap = MnpWrapRxData (Instance, &RxData);
      if (RxDataWrap == NULL) {
        continue;
      }
 
      //
      // Associate RxDataWrap with Nbuf and increase the RefCnt.
      //
      RxDataWrap->Nbuf = Nbuf;
      NET_GET_REF (RxDataWrap->Nbuf);
 
      //
      // Queue the packet into the instance queue.
      //
      MnpQueueRcvdPacket (Instance, RxDataWrap);
    }
  }
}
 
EFI_STATUS
MnpReceivePacket (
  IN OUT MNP_DEVICE_DATA  *MnpDeviceData
  )
{
  EFI_STATUS                   Status;
  EFI_SIMPLE_NETWORK_PROTOCOL  *Snp;
  NET_BUF                      *Nbuf;
  UINT8                        *BufPtr;
  UINTN                        BufLen;
  UINTN                        HeaderSize;
  UINT32                       Trimmed;
  MNP_SERVICE_DATA             *MnpServiceData;
  UINT16                       VlanId;
  BOOLEAN                      IsVlanPacket;
 
  NET_CHECK_SIGNATURE (MnpDeviceData, MNP_DEVICE_DATA_SIGNATURE);
 
  Snp = MnpDeviceData->Snp;
  if (Snp->Mode->State != EfiSimpleNetworkInitialized) {
    //
    // The simple network protocol is not started.
    //
    return EFI_NOT_STARTED;
  }
 
  if (MnpDeviceData->RxNbufCache == NULL) {
    //
    // Try to get a new buffer as there may be buffers recycled.
    //
    MnpDeviceData->RxNbufCache = MnpAllocNbuf (MnpDeviceData);
 
    if (MnpDeviceData->RxNbufCache == NULL) {
      //
      // No available buffer in the buffer pool.
      //
      return EFI_DEVICE_ERROR;
    }
 
    NetbufAllocSpace (
      MnpDeviceData->RxNbufCache,
      MnpDeviceData->BufferLength,
      NET_BUF_TAIL
      );
  }
 
  Nbuf   = MnpDeviceData->RxNbufCache;
  BufLen = Nbuf->TotalSize;
  BufPtr = NetbufGetByte (Nbuf, 0, NULL);
  ASSERT (BufPtr != NULL);
 
  //
  // Receive packet through Snp.
  //
  Status = Snp->Receive (Snp, &HeaderSize, &BufLen, BufPtr, NULL, NULL, NULL);
  if (EFI_ERROR (Status)) {
    DEBUG_CODE_BEGIN ();
    if (Status != EFI_NOT_READY) {
      DEBUG ((DEBUG_WARN, "MnpReceivePacket: Snp->Receive() = %r.\n", Status));
    }
 
    DEBUG_CODE_END ();
 
    return Status;
  }
 
  //
  // Sanity check.
  //
  if ((HeaderSize != Snp->Mode->MediaHeaderSize) || (BufLen < HeaderSize)) {
    DEBUG (
      (DEBUG_WARN,
       "MnpReceivePacket: Size error, HL:TL = %d:%d.\n",
       HeaderSize,
       BufLen)
      );
    return EFI_DEVICE_ERROR;
  }
 
  Trimmed = 0;
  if (Nbuf->TotalSize != BufLen) {
    //
    // Trim the packet from tail.
    //
    Trimmed = NetbufTrim (Nbuf, Nbuf->TotalSize - (UINT32)BufLen, NET_BUF_TAIL);
    ASSERT (Nbuf->TotalSize == BufLen);
  }
 
  VlanId = 0;
  if (MnpDeviceData->NumberOfVlan != 0) {
    //
    // VLAN is configured, remove the VLAN tag if any
    //
    IsVlanPacket = MnpRemoveVlanTag (MnpDeviceData, Nbuf, &VlanId);
  } else {
    IsVlanPacket = FALSE;
  }
 
  MnpServiceData = MnpFindServiceData (MnpDeviceData, VlanId);
  if (MnpServiceData == NULL) {
    //
    // VLAN is not set for this tagged frame, ignore this packet
    //
    if (Trimmed > 0) {
      NetbufAllocSpace (Nbuf, Trimmed, NET_BUF_TAIL);
    }
 
    if (IsVlanPacket) {
      NetbufAllocSpace (Nbuf, NET_VLAN_TAG_LEN, NET_BUF_HEAD);
    }
 
    goto EXIT;
  }
 
  //
  // Enqueue the packet to the matched instances.
  //
  MnpEnqueuePacket (MnpServiceData, Nbuf);
 
  if (Nbuf->RefCnt > 2) {
    //
    // RefCnt > 2 indicates there is at least one receiver of this packet.
    // Free the current RxNbufCache and allocate a new one.
    //
    MnpFreeNbuf (MnpDeviceData, Nbuf);
 
    Nbuf                       = MnpAllocNbuf (MnpDeviceData);
    MnpDeviceData->RxNbufCache = Nbuf;
    if (Nbuf == NULL) {
      DEBUG ((DEBUG_ERROR, "MnpReceivePacket: Alloc packet for receiving cache failed.\n"));
      return EFI_DEVICE_ERROR;
    }
 
    NetbufAllocSpace (Nbuf, MnpDeviceData->BufferLength, NET_BUF_TAIL);
  } else {
    //
    // No receiver for this packet.
    //
    if (Trimmed > 0) {
      NetbufAllocSpace (Nbuf, Trimmed, NET_BUF_TAIL);
    }
 
    if (IsVlanPacket) {
      NetbufAllocSpace (Nbuf, NET_VLAN_TAG_LEN, NET_BUF_HEAD);
    }
 
    goto EXIT;
  }
 
  //
  // Deliver the queued packets.
  //
  MnpDeliverPacket (MnpServiceData);
 
EXIT:
 
  ASSERT (Nbuf->TotalSize == MnpDeviceData->BufferLength);
 
  return Status;
}
 
VOID
EFIAPI
MnpCheckPacketTimeout (
  IN EFI_EVENT  Event,
  IN VOID       *Context
  )
{
  MNP_DEVICE_DATA    *MnpDeviceData;
  MNP_SERVICE_DATA   *MnpServiceData;
  LIST_ENTRY         *Entry;
  LIST_ENTRY         *ServiceEntry;
  LIST_ENTRY         *RxEntry;
  LIST_ENTRY         *NextEntry;
  MNP_INSTANCE_DATA  *Instance;
  MNP_RXDATA_WRAP    *RxDataWrap;
  EFI_TPL            OldTpl;
 
  MnpDeviceData = (MNP_DEVICE_DATA *)Context;
  NET_CHECK_SIGNATURE (MnpDeviceData, MNP_DEVICE_DATA_SIGNATURE);
 
  NET_LIST_FOR_EACH (ServiceEntry, &MnpDeviceData->ServiceList) {
    MnpServiceData = MNP_SERVICE_DATA_FROM_LINK (ServiceEntry);
 
    NET_LIST_FOR_EACH (Entry, &MnpServiceData->ChildrenList) {
      Instance = NET_LIST_USER_STRUCT (Entry, MNP_INSTANCE_DATA, InstEntry);
      NET_CHECK_SIGNATURE (Instance, MNP_INSTANCE_DATA_SIGNATURE);
 
      if (!Instance->Configured || (Instance->ConfigData.ReceivedQueueTimeoutValue == 0)) {
        //
        // This instance is not configured or there is no receive time out,
        // just skip to the next instance.
        //
        continue;
      }
 
      OldTpl = gBS->RaiseTPL (TPL_NOTIFY);
 
      NET_LIST_FOR_EACH_SAFE (RxEntry, NextEntry, &Instance->RcvdPacketQueue) {
        RxDataWrap = NET_LIST_USER_STRUCT (RxEntry, MNP_RXDATA_WRAP, WrapEntry);
 
        //
        // TimeoutTick unit is microsecond, MNP_TIMEOUT_CHECK_INTERVAL unit is 100ns.
        //
        if (RxDataWrap->TimeoutTick >= (MNP_TIMEOUT_CHECK_INTERVAL / 10)) {
          RxDataWrap->TimeoutTick -= (MNP_TIMEOUT_CHECK_INTERVAL / 10);
        } else {
          //
          // Drop the timeout packet.
          //
          DEBUG ((DEBUG_WARN, "MnpCheckPacketTimeout: Received packet timeout.\n"));
          MnpRecycleRxData (NULL, RxDataWrap);
          Instance->RcvdPacketQueueSize--;
        }
      }
 
      gBS->RestoreTPL (OldTpl);
    }
  }
}
 
VOID
EFIAPI
MnpCheckMediaStatus (
  IN EFI_EVENT  Event,
  IN VOID       *Context
  )
{
  MNP_DEVICE_DATA              *MnpDeviceData;
  EFI_SIMPLE_NETWORK_PROTOCOL  *Snp;
  UINT32                       InterruptStatus;
 
  MnpDeviceData = (MNP_DEVICE_DATA *)Context;
  NET_CHECK_SIGNATURE (MnpDeviceData, MNP_DEVICE_DATA_SIGNATURE);
 
  Snp = MnpDeviceData->Snp;
  if (Snp->Mode->MediaPresentSupported) {
    //
    // Upon successful return of GetStatus(), the MediaPresent field of
    // EFI_SIMPLE_NETWORK_MODE will be updated to reflect any change of media status
    //
    Snp->GetStatus (Snp, &InterruptStatus, NULL);
  }
}
 
VOID
EFIAPI
MnpSystemPoll (
  IN EFI_EVENT  Event,
  IN VOID       *Context
  )
{
  MNP_DEVICE_DATA  *MnpDeviceData;
 
  MnpDeviceData = (MNP_DEVICE_DATA *)Context;
  NET_CHECK_SIGNATURE (MnpDeviceData, MNP_DEVICE_DATA_SIGNATURE);
 
  //
  // Try to receive packets from Snp.
  //
  MnpReceivePacket (MnpDeviceData);
 
  //
  // Dispatch the DPC queued by the NotifyFunction of rx token's events.
  //
  DispatchDpc ();
}