audk/OvmfPkg/VirtioNetDxe/SnpMcastIpToMac.c

/** @file

  Implementation of the SNP.McastIpToMac() function and its private helpers if
  any.

  Copyright (C) 2013, Red Hat, Inc.
  Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>

  SPDX-License-Identifier: BSD-2-Clause-Patent

**/

#include <Library/UefiBootServicesTableLib.h>

#include "VirtioNet.h"

/**
  Converts a multicast IP address to a multicast HW MAC address.

  @param  This The protocol instance pointer.
  @param  IPv6 Set to TRUE if the multicast IP address is IPv6 [RFC 2460]. Set
               to FALSE if the multicast IP address is IPv4 [RFC 791].
  @param  IP   The multicast IP address that is to be converted to a multicast
               HW MAC address.
  @param  MAC  The multicast HW MAC address that is to be generated from IP.

  @retval EFI_SUCCESS           The multicast IP address was mapped to the
                                multicast HW MAC address.
  @retval EFI_NOT_STARTED       The network interface has not been started.
  @retval EFI_BUFFER_TOO_SMALL  The Statistics buffer was too small. The
                                current buffer size needed to hold the
                                statistics is returned in StatisticsSize.
  @retval EFI_INVALID_PARAMETER One or more of the parameters has an
                                unsupported value.
  @retval EFI_DEVICE_ERROR      The command could not be sent to the network
                                interface.
  @retval EFI_UNSUPPORTED       This function is not supported by the network
                                interface.

**/

EFI_STATUS
EFIAPI
VirtioNetMcastIpToMac (
  IN EFI_SIMPLE_NETWORK_PROTOCOL *This,
  IN BOOLEAN                     IPv6,
  IN EFI_IP_ADDRESS              *Ip,
  OUT EFI_MAC_ADDRESS            *Mac
  )
{
  VNET_DEV   *Dev;
  EFI_TPL    OldTpl;
  EFI_STATUS Status;

  //
  // http://en.wikipedia.org/wiki/Multicast_address
  //
  if (This == NULL || Ip == NULL || Mac == NULL ||
      ( IPv6 && (Ip->v6.Addr[0]       ) != 0xFF) || // invalid IPv6 mcast addr
      (!IPv6 && (Ip->v4.Addr[0] & 0xF0) != 0xE0)    // invalid IPv4 mcast addr
      ) {
    return EFI_INVALID_PARAMETER;
  }

  Dev = VIRTIO_NET_FROM_SNP (This);
  OldTpl = gBS->RaiseTPL (TPL_CALLBACK);
  switch (Dev->Snm.State) {
  case EfiSimpleNetworkStopped:
    Status = EFI_NOT_STARTED;
    goto Exit;
  case EfiSimpleNetworkStarted:
    Status = EFI_DEVICE_ERROR;
    goto Exit;
  default:
    break;
  }

  //
  // http://en.wikipedia.org/wiki/IP_multicast#Layer_2_delivery
  //
  if (IPv6) {
    Mac->Addr[0] = 0x33;
    Mac->Addr[1] = 0x33;
    Mac->Addr[2] = Ip->v6.Addr[12];
    Mac->Addr[3] = Ip->v6.Addr[13];
    Mac->Addr[4] = Ip->v6.Addr[14];
    Mac->Addr[5] = Ip->v6.Addr[15];
  }
  else {
    Mac->Addr[0] = 0x01;
    Mac->Addr[1] = 0x00;
    Mac->Addr[2] = 0x5E;
    Mac->Addr[3] = Ip->v4.Addr[1] & 0x7F;
    Mac->Addr[4] = Ip->v4.Addr[2];
    Mac->Addr[5] = Ip->v4.Addr[3];
  }
  Status = EFI_SUCCESS;

Exit:
  gBS->RestoreTPL (OldTpl);
  return Status;
}