tcputils.cs

using System.Diagnostics;
using System.Net;
using System.Runtime.InteropServices;

namespace CheckTcpConnection;
public class Main
{
    [DllImport("iphlpapi")]
    public static extern unsafe uint GetTcpTable2(MIB_TCPTABLE2* TcpTable, ref uint SizePointer, bool Order);

    [StructLayout(LayoutKind.Sequential)]
    public struct MIB_TCPTABLE2 {
        public uint dwNumEntries;
        public MIB_TCPROW2 table;
    }

    [StructLayout(LayoutKind.Sequential)]
    public struct MIB_TCPROW2 {
        public const uint SIZE = 0x1C;
        public MibTcpState dwState;
        public uint dwLocalAddr;
        public uint dwLocalPort;
        public uint dwRemoteAddr;
        public uint dwRemotePort;
        public uint dwOwningPid;
        public TCP_CONNECTION_OFFLOAD_STATE dwOffloadState;
    }
    
    public enum TCP_CONNECTION_OFFLOAD_STATE {
        TcpConnectionOffloadStateInHost = 0,
        TcpConnectionOffloadStateOffloading = 1,
        TcpConnectionOffloadStateOffloaded = 2,
        TcpConnectionOffloadStateUploading = 3,
        TcpConnectionOffloadStateMax = 4,
    }    
    
    public enum MibTcpState : uint
    {
        CLOSED = 1,
        LISTENING = 2,
        SYN_SENT = 3,
        SYN_RCVD = 4,
        ESTABLISHED = 5,
        FIN_WAIT1 = 6,
        FIN_WAIT2 = 7,
        CLOSE_WAIT = 8,
        CLOSING = 9,
        LAST_ACK = 10,
        TIME_WAIT = 11,
        DELETE_TCB = 12,
        NONE = 0
    }
    
    public static unsafe MIB_TCPROW2[] GetTcpRows() {
        uint sizePointer = 0;
        const bool order = false;
        GetTcpTable2(null, ref sizePointer, order);

        var rawTableBytes = new byte[sizePointer];
        fixed (byte* ptbl = rawTableBytes) {
            var error = GetTcpTable2((MIB_TCPTABLE2*)ptbl, ref sizePointer, order);
            Debug.Assert(error == 0);
            if (error != 0)
                return Array.Empty<MIB_TCPROW2>();
            var elems = (int)((MIB_TCPTABLE2*)ptbl)->dwNumEntries;
            var res = new MIB_TCPROW2[elems];
            var pelem = (MIB_TCPROW2*)(ptbl + 4);
            var p = ptbl + 4;
            for (var i = 0; i < res.Length; i++, p += MIB_TCPROW2.SIZE)
                res[i] = *(MIB_TCPROW2*)p;
            return res;
        }
    }
    
    public void Run()
    {
        var tcpRows = GetTcpRows();
        var dofusProcesses = Process.GetProcessesByName("Dofus Retro");

        foreach (var process in dofusProcesses)
        {
            var tcpConnections = tcpRows.Where(x => x.dwOwningPid == process.Id);

            foreach (var connection in tcpConnections)
            {
                Console.WriteLine(
                    $"Le processus {process.Id} à une connexion TCP ouverte sur {new IPAddress(connection.dwRemoteAddr)}:{IPAddress.HostToNetworkOrder((short)(connection.dwRemotePort & 0xFFFF))}");
            }
        }
    }
}