/// <summary>
/// This function reads and parses the active TCP socket connections available
/// and stores them in a list.
/// </summary>
/// <returns>
/// It returns the current set of TCP 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 <TcpProcessRecord> GetAllTcpConnections()
{
int bufferSize = 0;
List <TcpProcessRecord> tcpTableRecords = new List <TcpProcessRecord>(100);
// Getting the size of TCP table, that is returned in 'bufferSize' variable.
uint result = WinAPIWrapper.GetExtendedTcpTable(IntPtr.Zero, ref bufferSize, true, AF_INET,
TcpTableClass.TCP_TABLE_OWNER_PID_ALL);
// Allocating memory from the unmanaged memory of the process by using the
// specified number of bytes in 'bufferSize' variable.
IntPtr tcpTableRecordsPtr = Marshal.AllocHGlobal(bufferSize);
try
{
// The size of the table returned in 'bufferSize' variable in previous
// call must be used in this subsequent call to 'GetExtendedTcpTable'
// function in order to successfully retrieve the table.
result = WinAPIWrapper.GetExtendedTcpTable(tcpTableRecordsPtr, ref bufferSize, true,
AF_INET, TcpTableClass.TCP_TABLE_OWNER_PID_ALL);
// Non-zero value represent the function 'GetExtendedTcpTable' failed,
// hence empty list is returned to the caller function.
if (result != 0)
{
return(new List <TcpProcessRecord>());
}
// Marshals data from an unmanaged block of memory to a newly allocated
// managed object 'tcpRecordsTable' of type 'MIB_TCPTABLE_OWNER_PID'
// to get number of entries of the specified TCP table structure.
MIB_TCPTABLE_OWNER_PID tcpRecordsTable = (MIB_TCPTABLE_OWNER_PID)
Marshal.PtrToStructure(tcpTableRecordsPtr,
typeof(MIB_TCPTABLE_OWNER_PID));
IntPtr tableRowPtr = (IntPtr)((long)tcpTableRecordsPtr +
Marshal.SizeOf(tcpRecordsTable.dwNumEntries));
// Reading and parsing the TCP records one by one from the table and
// storing them in a list of 'TcpProcessRecord' structure type objects.
for (int row = 0; row < tcpRecordsTable.dwNumEntries; row++)
{
MIB_TCPROW_OWNER_PID tcpRow = (MIB_TCPROW_OWNER_PID)Marshal.
PtrToStructure(tableRowPtr, typeof(MIB_TCPROW_OWNER_PID));
tcpTableRecords.Add(new TcpProcessRecord(tcpRow.localAddr,
tcpRow.remoteAddr,
BitConverter.ToUInt16(new byte[2] {
tcpRow.localPort[1],
tcpRow.localPort[0]
}, 0),
BitConverter.ToUInt16(new byte[2] {
tcpRow.remotePort[1],
tcpRow.remotePort[0]
}, 0),
tcpRow.owningPid, tcpRow.state));
tableRowPtr = (IntPtr)((long)tableRowPtr + Marshal.SizeOf(tcpRow));
}
}
catch (OutOfMemoryException outOfMemoryException)
{
}
catch (Exception exception)
{
}
finally
{
Marshal.FreeHGlobal(tcpTableRecordsPtr);
}
return(tcpTableRecords != null?tcpTableRecords.Distinct()
.ToList <TcpProcessRecord>() : new List <TcpProcessRecord>());
}
