# helper method to enumerate the registered communication ports for a filter driver.
#     filter - address of a filter driver
dx @$enumPortsForFilter = (filter => Debugger.Utility.Collections.FromListEntry(((fltmgr!_FLT_FILTER*)filter)->PortList.mList, "fltmgr!_FLT_PORT_OBJECT", "FilterLink"))

# helper method to find all the open handles to a file pointing to a specific device:
#     proc - debugger data model process (such as @$cursession.Process[4]
#     dev - address of a device object, such as the address of \FileSystem\Filters\FltMgrMsg
dx @$getHandlesToDevice = ((proc, dev) => proc.Io.Handles.Where(h => h.Type == "File" && h.Object.UnderlyingObject.DeviceObject == dev))

# helper method to get all the IRPs waiting on a communication port.
#     port - address of a port, such as the ones returned from @$enumPortsForFilter
dx @$getIrpList = (port => Debugger.Utility.Collections.FromListEntry(((fltmgr!_FLT_PORT_OBJECT*)port)->MsgQ.WaiterQ.mList, "nt!_IRP", "Tail.Overlay.ListEntry"))

# print all registered connection ports by iterating over the kernel handle table. Print the name and number of connections for each one.
dx -g @$cursession.Processes[4].Io.Handles.Where(h => !__iserror(h.Type == "FilterConnectionPort") && h.Type == "FilterConnectionPort").Select(h => new {Name = h.ObjectName, Object = (fltmgr!_FLT_SERVER_PORT_OBJECT*)(&h.Object.Body), NumberOfConnections = ((fltmgr!_FLT_SERVER_PORT_OBJECT*)(&h.Object.Body))->NumberOfConnections})