private unsafe static void GetAddressesForAdapter(int index, ref MulticastIPAddressInformationCollection addressList)
{
int length = 0;
int ret = (NativeMethods.GetAdaptersAddresses(AddressFamily.Unspecified,
MULTICAST_FLAGS,
IntPtr.Zero,
null,
ref length));
byte[] data = new byte[length];
fixed(byte *pData = data)
{
byte *p = pData;
ret = (NativeMethods.GetAdaptersAddresses(AddressFamily.Unspecified,
MULTICAST_FLAGS,
IntPtr.Zero,
p,
ref length));
if ((length == 0) || (ret != 0))
{
// FAILED
}
// find this adapter by index
int INDEX_OFFSET = 4;
int currentIndex = 0;
uint pNext = 0;
do
{
p += INDEX_OFFSET; // past length
currentIndex = (int)*((int *)p);
if (index == currentIndex)
{
p -= 4;
GetAddressesForAdapter(p, ref addressList);
return;
}
p += 4; // past index
pNext = (uint)*((uint *)p);
p = (byte *)pNext;
} while (pNext != 0);
// failed to find index
throw new ArgumentException("Index not found");
}
}
private unsafe static void GetAddressesForAdapter(byte *pData, ref MulticastIPAddressInformationCollection addressList)
{
addressList.InternalClear();
/*
* typedef struct _IP_ADAPTER_ADDRESSES {
* union {
* ULONGLONG Alignment;
* struct {
* ULONG Length;
* DWORD IfIndex;
* };
* };
* struct _IP_ADAPTER_ADDRESSES* Next;
* PCHAR AdapterName;
* PIP_ADAPTER_UNICAST_ADDRESS FirstUnicastAddress;
* PIP_ADAPTER_ANYCAST_ADDRESS FirstAnycastAddress;
* PIP_ADAPTER_MULTICAST_ADDRESS FirstMulticastAddress;
* PIP_ADAPTER_DNS_SERVER_ADDRESS FirstDnsServerAddress;
* PWCHAR DnsSuffix;
* PWCHAR Description;
* PWCHAR FriendlyName;
* BYTE PhysicalAddress[MAX_ADAPTER_ADDRESS_LENGTH];
* DWORD PhysicalAddressLength;
* DWORD Flags;
*
*
* typedef struct _SOCKET_ADDRESS {
* LPSOCKADDR lpSockaddr ;
* INT iSockaddrLength ;
* } SOCKET_ADDRESS, *PSOCKET_ADDRESS, FAR * LPSOCKET_ADDRESS ;
*
*
*/
int addressListOffset = 0;
byte *p = pData;
uint *pNext = null;
addressListOffset = 28;
p += addressListOffset;
/*
* typedef struct _IP_ADAPTER_MULTICAST_ADDRESS {
* union {
* ULONGLONG Alignment;
* struct {
* ULONG Length;
* DWORD Flags;
* }
* };
* struct _IP_ADAPTER_MULTICAST_ADDRESS* Next;
* SOCKET_ADDRESS Address;
* } IP_ADAPTER_MULTICAST_ADDRESS, *PIP_ADAPTER_MULTICAST_ADDRESS;
*/
uint pAddress = (uint)*((uint *)p);
p = (byte *)pAddress;
if (p == null)
{
return;
}
MulticastIPAddressInformation info;
do
{
info = new MulticastIPAddressInformation();
// past length
p += 4;
// flags
info.AdapterFlags = (PerAdapterFlags)((int)*((int *)p));
p += 4;
// next
pNext = (uint *)*((uint *)p);
p += 4;
// socket address pointer
info.Address = GetAddressFromSocketAddressPointer(p);
p += 4;
p = (byte *)pNext;
addressList.InternalAdd(info);
}while (pNext != null);
}