/// <summary>
/// This function reads and parses the active UDP socket connections available
/// and stores them in a list.
/// </summary>
/// <returns>
/// It returns the current set of UDP socket connections which are active.
/// </returns>
/// <exception cref="OutOfMemoryException">
/// This exception may be thrown by the function Marshal.AllocHGlobal when there
/// is insufficient memory to satisfy the request.
/// </exception>
public static List <UdpProcessRecord> GetAllUdpConnections()
{
int bufferSize = 0;
List <UdpProcessRecord> udpTableRecords = new List <UdpProcessRecord>(100);
// Getting the size of UDP table, that is returned in 'bufferSize' variable.
_ = WinAPIWrapper.GetExtendedUdpTable(IntPtr.Zero, ref bufferSize, true,
AF_INET, UdpTableClass.UDP_TABLE_OWNER_PID);
// Allocating memory from the unmanaged memory of the process by using the
// specified number of bytes in 'bufferSize' variable.
IntPtr udpTableRecordPtr = Marshal.AllocHGlobal(bufferSize);
try
{
// The size of the table returned in 'bufferSize' variable in previous
// call must be used in this subsequent call to 'GetExtendedUdpTable'
// function in order to successfully retrieve the table.
uint result = WinAPIWrapper.GetExtendedUdpTable(udpTableRecordPtr, ref bufferSize, true,
AF_INET, UdpTableClass.UDP_TABLE_OWNER_PID);
// Non-zero value represent the function 'GetExtendedUdpTable' failed,
// hence empty list is returned to the caller function.
if (result != 0)
{
return(new List <UdpProcessRecord>());
}
// Marshals data from an unmanaged block of memory to a newly allocated
// managed object 'udpRecordsTable' of type 'MIB_UDPTABLE_OWNER_PID'
// to get number of entries of the specified TCP table structure.
MIB_UDPTABLE_OWNER_PID udpRecordsTable = (MIB_UDPTABLE_OWNER_PID)
Marshal.PtrToStructure(udpTableRecordPtr, typeof(MIB_UDPTABLE_OWNER_PID));
IntPtr tableRowPtr = (IntPtr)((long)udpTableRecordPtr +
Marshal.SizeOf(udpRecordsTable.dwNumEntries));
// Reading and parsing the UDP records one by one from the table and
// storing them in a list of 'UdpProcessRecord' structure type objects.
for (int i = 0; i < udpRecordsTable.dwNumEntries; i++)
{
MIB_UDPROW_OWNER_PID udpRow = (MIB_UDPROW_OWNER_PID)
Marshal.PtrToStructure(tableRowPtr, typeof(MIB_UDPROW_OWNER_PID));
udpTableRecords.Add(new UdpProcessRecord(udpRow.localAddr,
BitConverter.ToUInt16(new byte[2] {
udpRow.localPort[1],
udpRow.localPort[0]
}, 0), udpRow.owningPid));
tableRowPtr = (IntPtr)((long)tableRowPtr + Marshal.SizeOf(udpRow));
}
}
//catch (OutOfMemoryException outOfMemoryException)
//{
//}
//catch (Exception exception)
//{
//}
finally
{
Marshal.FreeHGlobal(udpTableRecordPtr);
}
return(udpTableRecords != null?udpTableRecords.Distinct()
.ToList <UdpProcessRecord>() : new List <UdpProcessRecord>());
}
