使用C＃将端口号引用到服务名称

Question

在Linux上使用MONO。

如何使用C＃将端口号与服务配对？

示例：

port 80 = http
port 443 = https

并将其输出到控制台，我需要这个用于我构建的简单端口扫描程序。

我知道这个函数存在于ruby中：

Socket.getservbyport(80, "tcp")

Answer 1

Windows版

更新：看到太晚了，海报在提出问题后添加了Linux和Mono标签，因此写了一个Windows实现。在Linux上，在第二篇文章中使用Mono版本。

穆罕默德的解决方案在很多方面比替代方案更便携。 getservbyname（）和getservbyport（）是依赖于平台的，需要使用P / Invoke在Windows上使用c＃，也很可能在Mono上使用。

要在Mono中实现下面的代码，您需要使用特定于平台的API（标头为netdb.h）进行PInvoke - 请注意，WSAStartUp（）和WSACleanUp（）是特定于Windows的套接字初始化函数，这些函数无关紧要在Linux系统上。目前没有单声道设置，因此无法提供特定于Linux的解决方案，但如果您愿意跳过这里的箍，那么可以使用Windows（32位）示例来实现代码：

namespace SocketTest
{
    using System;
    using System.Net;
    using System.Net.Sockets;
    using System.Runtime.InteropServices;
    using System.Runtime.Serialization;



    [Serializable]
    public class SocketUtilException : Exception
    {

        public SocketUtilException()
        {
        }

        public SocketUtilException(string message)
            : base(message)
        {
        }

        public SocketUtilException(string message, Exception inner)
            : base(message, inner)
        {
        }

        protected SocketUtilException(
            SerializationInfo info, StreamingContext context)
            : base(info, context)
        {
        }
    }
    public static class SocketUtil
    {
        private const int WSADESCRIPTION_LEN = 256;

        private const int WSASYSSTATUS_LEN = 128;

        [StructLayout(LayoutKind.Sequential)]
        public struct WSAData
        {
            public short wVersion;
            public short wHighVersion;

            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = WSADESCRIPTION_LEN+1)]
            public string szDescription;

            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = WSASYSSTATUS_LEN+1)]
            public string wSystemStatus;
            [Obsolete("Ignored when wVersionRequested >= 2.0")]
            public ushort wMaxSockets;
            [Obsolete("Ignored when wVersionRequested >= 2.0")]
            public ushort wMaxUdpDg;
            public IntPtr dwVendorInfo;
        }


        [StructLayoutAttribute(LayoutKind.Sequential)]
        public struct servent
        {
            public string s_name;
            public IntPtr s_aliases;
            public short s_port;
            public string s_proto;
        }

        private static ushort MakeWord ( byte low, byte high)
        {

            return  (ushort)((ushort)(high << 8) | low);
        }

        [DllImport("ws2_32.dll", CharSet = CharSet.Auto, ExactSpelling = true, SetLastError = true)]
        private static extern int WSAStartup(ushort wVersionRequested, ref WSAData wsaData);
        [DllImport("ws2_32.dll", CharSet = CharSet.Auto, ExactSpelling = true, SetLastError = true)]
        private static extern int WSACleanup();
        [DllImport("ws2_32.dll",  SetLastError = true, CharSet = CharSet.Ansi)]
        private static extern IntPtr getservbyname(string name, string proto);
        [DllImport("ws2_32.dll", SetLastError = true, CharSet = CharSet.Ansi)]
        private static extern IntPtr getservbyport(short port, string proto);

        public static string GetServiceByPort(short port, string protocol)
        {

            var wsaData = new WSAData();
            if (WSAStartup(MakeWord(2, 2), ref wsaData) != 0)
            {
                throw new SocketUtilException("WSAStartup",
                    new SocketException(Marshal.GetLastWin32Error()));

            }
            try
            {
                var netport = Convert.ToInt16(IPAddress.HostToNetworkOrder(port));
                var result = getservbyport(netport, protocol);
                if (IntPtr.Zero == result)
                {
                    throw new SocketUtilException(
                        string.Format("Could not resolve service for port {0}", port),
                        new SocketException(Marshal.GetLastWin32Error()));
                }
                var srvent = (servent)Marshal.PtrToStructure(result, typeof(servent));
                return srvent.s_name;;
            }
            finally
            {
                WSACleanup();
            }
        }


        public static short GetServiceByName(string service, string protocol)
        {

            var wsaData = new WSAData();
            if(WSAStartup(MakeWord(2,2), ref wsaData) != 0)
            {
                throw new SocketUtilException("WSAStartup", 
                    new SocketException(Marshal.GetLastWin32Error()));

            }
            try
            {
                var result = getservbyname(service, protocol);
                if (IntPtr.Zero == result)
                {
                    throw new SocketUtilException(
                        string.Format("Could not resolve port for service {0}", service), 
                        new SocketException(Marshal.GetLastWin32Error()));
                }
                var srvent = (servent)Marshal.PtrToStructure(result, typeof(servent));
                return Convert.ToInt16(IPAddress.NetworkToHostOrder(srvent.s_port));
            }
            finally
            {
                WSACleanup();
            }



        }
    }
    class Program
    {


        static void Main(string[] args)
        {

            try
            {


                var port = SocketUtil.GetServiceByName("http", "tcp");
                Console.WriteLine("http runs on port {0}", port);

                Console.WriteLine("Reverse call:{0}", SocketUtil.GetServiceByPort(port, "tcp"));



            }
            catch(SocketUtilException exception)
            {
                Console.WriteLine(exception.Message);
                if(exception.InnerException != null)
                {
                    Console.WriteLine(exception.InnerException.Message);
                }
            }


        }
    }

Answer 2

Mono Linux版

我手上有点时间，所以在我的Ubuntu Linux机器上安装Mono进行测试。 getservbyport（）和getservbyname（）的Mono PInvoke实现比在Windows上简单（只需加载内置网络内容的libc）。以下是可供参考的示例代码，以防任何人想要它;）

namespace SocketUtil
{
    using System;
    using System.Net;
    using System.Collections.Generic;
    using System.Runtime.InteropServices;
    using System.Runtime.Serialization;

    [Serializable]
    public class SocketUtilException : Exception
    {

        public SocketUtilException()
        {
        }

        public SocketUtilException(string message)
            : base(message)
        {
        }

        public SocketUtilException(string message, Exception inner)
            : base(message, inner)
        {
        }

        protected SocketUtilException(
            SerializationInfo info, StreamingContext context)
            : base(info, context)
        {
        }
    }

    public static class SocketUtil
    {

        [StructLayoutAttribute(LayoutKind.Sequential)]
        public struct servent
        {
            public string s_name;
            public IntPtr s_aliases;
            public ushort s_port;
            public string s_proto;
        }


        [DllImport("libc", SetLastError = true, CharSet = CharSet.Ansi)]
        private static extern IntPtr getservbyname(string name, string proto);
        [DllImport("libc", SetLastError = true, CharSet = CharSet.Ansi)]
        private static extern IntPtr getservbyport(ushort port, string proto);

        public static string GetServiceByPort(ushort port, string protocol, out List<string> aliases)
        {
            var netport = unchecked((ushort)IPAddress.HostToNetworkOrder(unchecked((short)port)));
            var result = getservbyport(netport, protocol);
            if (IntPtr.Zero == result)
            {
                throw new SocketUtilException(
                    string.Format("Could not resolve service for port {0}", port));
            }
            var srvent = (servent)Marshal.PtrToStructure(result, typeof(servent));
            aliases = GetAliases(srvent);
            return srvent.s_name;

        }

        private static List<string> GetAliases(servent srvent)
        {
            var aliases = new List<string>();
            if (srvent.s_aliases != IntPtr.Zero)
            {
                IntPtr cb;

                for (var i = 0;
                    (cb = Marshal.ReadIntPtr(srvent.s_aliases, i)) != IntPtr.Zero;
                    i += Marshal.SizeOf(cb))
                {
                    aliases.Add(Marshal.PtrToStringAnsi(cb));
                }
            }
            return aliases;
        }

        public static ushort GetServiceByName(string service, string protocol, out List<string> aliases)
        {

            var result = getservbyname(service, protocol);
            if (IntPtr.Zero == result)
            {
                throw new SocketUtilException(
                    string.Format("Could not resolve port for service {0}", service));
            }

            var srvent = (servent)Marshal.PtrToStructure(result, typeof(servent));
            aliases = GetAliases(srvent);
            var hostport = IPAddress.NetworkToHostOrder(unchecked((short)srvent.s_port));
            return unchecked((ushort)hostport);

        }
    }
    class Program
    {

        static void Main(string[] args)
        {

            try
            {
                List<string> aliases;
                var port = SocketUtil.GetServiceByName("https", "tcp", out aliases);

                Console.WriteLine("https runs on port {0}", port);
                foreach (var alias in aliases)
                {
                    Console.WriteLine(alias);
                }

                Console.WriteLine("Reverse call:{0}", SocketUtil.GetServiceByPort(port, "tcp", out aliases));

            }
            catch (SocketUtilException exception)
            {
                Console.WriteLine(exception.Message);
                if (exception.InnerException != null)
                {
                    Console.WriteLine(exception.InnerException.Message);
                }
            }

        }
    }
}

Answer 3

在Windows上有一个“服务”文件，位于System32 \ Drivers \ Etc \文件夹中。我编写了以下代码来解析它。您可以使用它来查找所需端口的信息：

class Program
{
    static void Main(string[] args)
    {
        var services = ReadServicesFile();

        // For example, I want to find information about port 443 of TCP service
        var port443Info = services.FirstOrDefault(s => s.Port == 443 && s.Type.Equals("tcp"));

        if (port443Info != null)
        {
            Console.WriteLine("TCP Port = {0}, Service name = {1}", port443Info.Port, port443Info.Name);
        }

    }

    static List<ServiceInfo> ReadServicesFile()
    {
        var sysFolder = Environment.GetFolderPath(Environment.SpecialFolder.System);
        if (!sysFolder.EndsWith("\\"))
            sysFolder += "\\";

        var svcFileName = sysFolder + "drivers\\etc\\services";

        var lines = File.ReadAllLines(svcFileName);

        var result = new List<ServiceInfo>();
        foreach (var line in lines)
        {
            if (string.IsNullOrEmpty(line) || line.StartsWith("#"))
                continue;

            var info = new ServiceInfo();

            var index = 0;

            // Name
            info.Name = line.Substring(index, 16).Trim();
            index += 16;

            // Port number and type
            var temp = line.Substring(index, 9).Trim();
            var tempSplitted = temp.Split('/');

            info.Port = ushort.Parse(tempSplitted[0]);
            info.Type = tempSplitted[1].ToLower();

            result.Add(info);
        }

        return result;
    }
}

您还需要以下类声明：

class ServiceInfo
{
    public ushort Port { get; set; }
    public string Name { get; set; }
    public string Type { get; set; }
}