source: branches/eraser6/6.0/Eraser.Util/NetApi.cs @ 1677

/* 
 * $Id$
 * Copyright 2008-2010 The Eraser Project
 * Original Author: Joel Low <lowjoel@users.sourceforge.net>
 * Modified By:
 * 
 * This file is part of Eraser.
 * 
 * Eraser is free software: you can redistribute it and/or modify it under the
 * terms of the GNU General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any later
 * version.
 * 
 * Eraser is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
 * A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 * 
 * A copy of the GNU General Public License can be found at
 * <http://www.gnu.org/licenses/>.
 */

using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;

namespace Eraser.Util
{
    public static class NetApi
    {
        /// <summary>
        /// The NetStatisticsGet function retrieves operating statistics for a service.
        /// Currently, only the workstation and server services are supported.
        /// </summary>
        /// <param name="server">Pointer to a string that specifies the DNS or
        /// NetBIOS name of the server on which the function is to execute. If
        /// this parameter is NULL, the local computer is used.</param>
        /// <param name="service">Pointer to a string that specifies the name of
        /// the service about which to get the statistics. Only the values
        /// SERVICE_SERVER and SERVICE_WORKSTATION are currently allowed.</param>
        /// <param name="level">Specifies the information level of the data.
        /// This parameter must be 0.</param>
        /// <param name="options">This parameter must be zero.</param>
        /// <param name="bufptr">Pointer to the buffer that receives the data. The
        /// format of this data depends on the value of the level parameter.
        /// This buffer is allocated by the system and must be freed using the
        /// NetApiBufferFree function. For more information, see Network Management
        /// Function Buffers and Network Management Function Buffer Lengths.</param>
        /// <returns>If the function succeeds, the return value is NERR_Success.
        /// 
        /// If the function fails, the return value is a system error code. For
        /// a list of error codes, see System Error Codes.</returns>
        public static byte[] NetStatisticsGet(string server, NetApiService service,
            uint level, uint options)
        {
            IntPtr netAPIStats = IntPtr.Zero;
            string serviceName = "Lanman" + service.ToString();
            if (NativeMethods.NetStatisticsGet(server, serviceName, level, options, out netAPIStats) == 0)
            {
                try
                {
                    //Get the size of the buffer
                    uint size = 0;
                    NativeMethods.NetApiBufferSize(netAPIStats, out size);
                    byte[] result = new byte[size];

                    //Copy the buffer
                    Marshal.Copy(result, 0, netAPIStats, result.Length);

                    //Return the result
                    return result;
                }
                finally
                {
                    //Free the statistics buffer
                    NativeMethods.NetApiBufferFree(netAPIStats);
                }
            }

            return null;
        }

        internal static class NativeMethods
        {
            [DllImport("Netapi32.dll", CharSet = CharSet.Unicode)]
            public static extern uint NetStatisticsGet(string server, string service,
                uint level, uint options, out IntPtr bufptr);

            /// <summary>
            /// The NetApiBufferSize function returns the size, in bytes, of a buffer
            /// allocated by a call to the NetApiBufferAllocate function.
            /// </summary>
            /// <param name="Buffer">Pointer to a buffer returned by the NetApiBufferAllocate
            /// function.</param>
            /// <param name="ByteCount">Receives the size of the buffer, in bytes.</param>
            /// <returns>If the function succeeds, the return value is NERR_Success.
            /// 
            /// If the function fails, the return value is a system error code. For
            /// a list of error codes, see System Error Codes.</returns>
            [DllImport("Netapi32.dll")]
            public static extern uint NetApiBufferSize(IntPtr Buffer, out uint ByteCount);

            /// <summary>
            /// The NetApiBufferFree function frees the memory that the NetApiBufferAllocate
            /// function allocates. Call NetApiBufferFree to free the memory that other
            /// network management functions return.
            /// </summary>
            /// <param name="Buffer">Pointer to a buffer returned previously by another
            /// network management function.</param>
            /// <returns>If the function succeeds, the return value is NERR_Success.
            /// 
            /// If the function fails, the return value is a system error code. For
            /// a list of error codes, see System Error Codes.</returns>
            [DllImport("Netapi32.dll")]
            public static extern uint NetApiBufferFree(IntPtr Buffer);

            private const uint NERR_Success = 0;
        }
    }

    public enum NetApiService
    {
        Workstation,
        Server
    }
}