有没有类似局域网的 ssid 之类的东西？ / 我可以识别当前的网络吗？

Question

我正在编写一个 c# 程序，我应该将 PC 连接到的当前网络与数据库进行比较。

使用 W-LAN 很容易（SSID），但是如果用户通过 LAN 连接，我如何识别网络并且 SSID 是最佳解决方案？

谢谢。

Answer 1

如果你想走默认网关的 MAC 路由试试这个：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Net;
using System.Net.NetworkInformation;
using System.Net.Sockets;
using System.Runtime.InteropServices;
using System.Threading.Tasks;

namespace NetworkIdentifier
{
    public class Program
    {
        public static void Main(string[] args)
        {
            var macAddressOfGateway = GetMacAddressOfGateway();
            Console.WriteLine(macAddressOfGateway);
            Console.ReadLine();
        }

        private static string GetMacAddressOfGateway()
        {
            var networkInterface = GetBestNetworkInterface();
            var gatewayAddress = networkInterface.GetIPProperties().GatewayAddresses.FirstOrDefault();
            if (gatewayAddress == null)
            {
                throw new InvalidOperationException("No gateway!");
            }

            var mac = GetMacAddress(gatewayAddress.Address);

            return MacToString(mac);
        }

        private static string MacToString(byte[] mac)
        {
            return string.Format("{0:X2}:{1:X2}:{2:X2}:{3:X2}:{4:X2}:{5:X2}", mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
        }

        public static NetworkInterface GetBestNetworkInterface()
        {
            var publicIpAddress = new IPAddress(0x08080808); // Googles DNS IP of 8.8.8.8 (Seems like a relatively safe hardcoded IP to pick :))
            var ipv4AddressAsUInt32 = BitConverter.ToUInt32(publicIpAddress.GetAddressBytes(), 0);
            uint interfaceindex;
            var result = Win32ApiCalls.GetBestInterface(ipv4AddressAsUInt32, out interfaceindex);
            if (result != 0)
            {
                throw new Win32Exception(result);
            }

            var networkCards = NetworkInterface.GetAllNetworkInterfaces().Where(x => x.OperationalStatus == OperationalStatus.Up);
            return networkCards.FirstOrDefault(networkInterface => networkInterface.GetIPProperties().GetIPv4Properties().Index == interfaceindex);
        }

        public static IPAddress GetDefaultGateway()
        {
            var networkInterface = GetBestNetworkInterface();
            if (networkInterface == null) return null;
            var address = networkInterface.GetIPProperties().GatewayAddresses.FirstOrDefault();
            return address.Address;
        }

        public static byte[] GetMacAddress(IPAddress address)
        {
            byte[] mac = new byte[6];
            uint len = (uint)mac.Length;
            byte[] addressBytes = address.GetAddressBytes();
            uint dest = ((uint)addressBytes[3] << 24)
              + ((uint)addressBytes[2] << 16)
              + ((uint)addressBytes[1] << 8)
              + ((uint)addressBytes[0]);
            if (Win32ApiCalls.SendARP(dest, 0, mac, ref len) != 0)
            {
                throw new Exception("The ARP request failed.");
            }
            return mac;
        }
    }

    public static class Win32ApiCalls
    {
        [DllImport("iphlpapi.dll", CharSet = CharSet.Auto)]
        public static extern int GetBestInterface(UInt32 destAddr, out UInt32 bestIfIndex);

        [DllImport("iphlpapi.dll", ExactSpelling = true)]
        public static extern int SendARP(uint destIP, uint srcIP, byte[] macAddress, ref uint macAddressLength);
    }
}

这需要大量的清理、警告、错误检查等（并且不适用于非 Windows 主机，所以甚至不要打扰 dnxcore :)）

** 告售者 :)

编辑：刚刚删除了我注释掉的行，因为它们没有添加任何有用的东西

Answer 2

默认网关将为您提供您所连接的路由器的 IP 地址（或为您分配 IP 地址的任何设备）。或者您可以获取网关的MAC地址等。