Bug 1616 - Runtime crash: cant marshal array as native type 04, when calling IPGlobalProperties.GetActiveTcpConnections() on Win32
Summary: Runtime crash: cant marshal array as native type 04, when calling IPGlobalPr...
Alias: None
Product: Class Libraries
Classification: Mono
Component: System ()
Version: master
Hardware: PC Windows
: --- normal
Target Milestone: Untriaged
Assignee: Bugzilla
Depends on:
Reported: 2011-10-20 14:06 UTC by Pablo Ruiz García
Modified: 2011-11-05 12:18 UTC (History)
3 users (show)

Is this bug a regression?: ---
Last known good build:

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Description Pablo Ruiz García 2011-10-20 14:06:49 UTC
Calling Sys.Net.NetworkInformation.IPGlobalProperties.GetActiveTcpConnections() on Win32 causes mono to creash with "cant marshal array as native type 04".

A simple test demostrating the issue would be like:

               public static void Main() {

However, after inspecting a little around mono code it seems to be related to the way marshaling layout for WIN32_IN6_ADDR is defined:

               [StructLayout (LayoutKind.Explicit)]
                struct Win32_IN6_ADDR
                        [FieldOffset (0)]
                        [MarshalAs ((short) UnmanagedType.U1, SizeConst = 16)]
                        public byte [] Bytes;

As it looks like the marshaller dont know howto marshal arrays of U1 native type.

I'm made a simple program demostrating the specific issue too by extracting some code from: mcs/class/System/System.Net.NetworkInformation/IPGlobalProperties.cs. 

using System;
using System.Runtime.InteropServices;
using System.Net.NetworkInformation;

namespace Test
                [StructLayout (LayoutKind.Explicit)]
                struct Win32_IN6_ADDR
                        [FieldOffset (0)]
                        [MarshalAs ((short) UnmanagedType.U1, SizeConst = 16)]
                        public byte [] Bytes;

                [StructLayout (LayoutKind.Sequential)]
                class Win32_MIB_TCP6ROW
                        public TcpState State;
                        public Win32_IN6_ADDR LocalAddr;
                        public uint LocalScopeId;
                        public int LocalPort;
                        public uint RemoteScopeId;
                        public int RemotePort;


        public static class Program {

               [DllImport ("Iphlpapi.dll")]
                static extern int GetTcpTable (byte [] pTcpTable, ref int pdwSize, bool bOrder);

                [DllImport ("Iphlpapi.dll")]
                static extern int GetTcp6Table (byte [] TcpTable, ref int SizePointer, bool Order);

                public static void Main() {

                        var data = Marshal.SizeOf (typeof (Win32_MIB_TCP6ROW));

Comment 1 Zoltan Varga 2011-10-20 16:18:03 UTC
The definition seems to be wrong, it should be something like:
   [MarshalAs ((short) UnmanagedType.ByValArray, SizeConst = 16)]

you can't convert a byte[] to an U1.
Comment 2 Rodrigo Kumpera 2011-11-03 18:35:10 UTC
A hard crash is hardly the way to go here.
Comment 3 Rodrigo Kumpera 2011-11-05 12:18:49 UTC
The win32 marshaling bug has been fixed in trunk/2.10/mobile-master. The marshaling hard crash still on the works and will eventually land master.