SnpMcastIpToMac.c

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#include <Library/UefiBootServicesTableLib.h>
 
#include "VirtioNet.h"
 
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;
}