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向系统插入自身做为主DNS

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This commit is contained in:
xljiulang 2021-07-20 20:25:14 +08:00
parent 9451152d76
commit 4ae101a76f
2 changed files with 115 additions and 99 deletions
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117
FastGithub.Dns/DnsServerHostedService.cs
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@ -6,8 +6,6 @@ using System;
using System.Diagnostics;
using System.Net;
using System.Net.Sockets;
using System.Runtime.InteropServices;
using System.Runtime.Versioning;
using System.Threading;
using System.Threading.Tasks;
@ -19,50 +17,37 @@ namespace FastGithub.Dns
sealed class DnsServerHostedService : BackgroundService
{
private readonly RequestResolver requestResolver;
private readonly FastGithubConfig fastGithubConfig;
private readonly HostsValidator hostsValidator;
private readonly ILogger<DnsServerHostedService> logger;
private readonly Socket socket = new(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
private readonly byte[] buffer = new byte[ushort.MaxValue];
private IPAddress[]? dnsAddresses;
[SupportedOSPlatform("windows")]
[DllImport("dnsapi.dll", EntryPoint = "DnsFlushResolverCache", SetLastError = true)]
private static extern void DnsFlushResolverCache();
/// <summary>
/// dns后台服务
/// </summary>
/// <param name="requestResolver"></param>
/// <param name="fastGithubConfig"></param>
/// <param name="hostsValidator"></param>
/// <param name="options"></param>
/// <param name="logger"></param>
public DnsServerHostedService(
RequestResolver requestResolver,
FastGithubConfig fastGithubConfig,
HostsValidator hostsValidator,
IOptionsMonitor<FastGithubOptions> options,
ILogger<DnsServerHostedService> logger)
{
this.requestResolver = requestResolver;
this.fastGithubConfig = fastGithubConfig;
this.hostsValidator = hostsValidator;
this.logger = logger;
options.OnChange(opt => FlushResolverCache());
}
/// <summary>
/// 刷新dns缓存
/// </summary>
private static void FlushResolverCache()
{
if (OperatingSystem.IsWindows())
{
DnsFlushResolverCache();
options.OnChange(opt => SystemDnsUtil.DnsFlushResolverCache());
}
}
/// <summary>
/// 启动dns
/// </summary>
@ -70,57 +55,75 @@ namespace FastGithub.Dns
/// <returns></returns>
public override async Task StartAsync(CancellationToken cancellationToken)
{
const int DNS_PORT = 53;
if (OperatingSystem.IsWindows() && UdpTable.TryGetOwnerProcessId(DNS_PORT, out var processId))
{
Process.GetProcessById(processId).Kill();
}
await BindAsync(this.socket, new IPEndPoint(IPAddress.Any, DNS_PORT), cancellationToken);
if (OperatingSystem.IsWindows())
{
const int SIO_UDP_CONNRESET = unchecked((int)0x9800000C);
this.socket.IOControl(SIO_UDP_CONNRESET, new byte[4], new byte[4]);
}
// 验证host文件
await this.BindAsync(cancellationToken);
await this.hostsValidator.ValidateAsync();
// 设置网关的dns
var secondary = this.fastGithubConfig.FastDns.Address;
this.dnsAddresses = this.SetNameServers(IPAddress.Loopback, secondary);
FlushResolverCache();
this.SetAsPrimitiveNameServer();
this.logger.LogInformation("dns服务启动成功");
await base.StartAsync(cancellationToken);
}
/// <summary>
/// 尝试多次绑定
/// </summary>
/// <param name="socket"></param>
/// <param name="localEndPoint"></param>
/// <param name="cancellationToken"></param>
/// <returns></returns>
private static async Task BindAsync(Socket socket, IPEndPoint localEndPoint, CancellationToken cancellationToken)
private async Task BindAsync(CancellationToken cancellationToken)
{
const int DNS_PORT = 53;
if (OperatingSystem.IsWindows() && UdpTable.TryGetOwnerProcessId(DNS_PORT, out var processId))
{
Process.GetProcessById(processId).Kill();
}
var localEndPoint = new IPEndPoint(IPAddress.Any, DNS_PORT);
var delay = TimeSpan.FromMilliseconds(100d);
for (var i = 10; i >= 0; i--)
{
try
{
socket.Bind(localEndPoint);
this.socket.Bind(localEndPoint);
break;
}
catch (Exception)
{
if (i == 0)
{
throw new FastGithubException($"无法监听{localEndPoint}，{localEndPoint.Port}的udp端口已被其它程序占用");
throw new FastGithubException($"无法监听{localEndPoint}，udp端口已被其它程序占用");
}
await Task.Delay(delay, cancellationToken);
}
}
if (OperatingSystem.IsWindows())
{
const int SIO_UDP_CONNRESET = unchecked((int)0x9800000C);
this.socket.IOControl(SIO_UDP_CONNRESET, new byte[4], new byte[4]);
}
}
/// <summary>
/// 设置自身为主dns
/// </summary>
private void SetAsPrimitiveNameServer()
{
if (OperatingSystem.IsWindows())
{
try
{
SystemDnsUtil.DnsSetPrimitive(IPAddress.Loopback);
SystemDnsUtil.DnsFlushResolverCache();
this.logger.LogInformation($"设置为本机dns成功");
}
catch (Exception ex)
{
this.logger.LogWarning($"设置为本机dns失败：{ex.Message}");
}
}
else
{
this.logger.LogWarning("平台不支持自动设置dns，请手动设置网卡的主dns为127.0.0.1");
}
}
/// <summary>
@ -178,40 +181,20 @@ namespace FastGithub.Dns
this.socket.Dispose();
this.logger.LogInformation("dns服务已终止");
if (this.dnsAddresses != null)
{
this.SetNameServers(this.dnsAddresses);
}
FlushResolverCache();
return base.StopAsync(cancellationToken);
}
/// <summary>
/// 设置dns
/// </summary>
/// <param name="nameServers"></param>
/// <returns></returns>
private IPAddress[]? SetNameServers(params IPAddress[] nameServers)
{
if (OperatingSystem.IsWindows())
{
try
{
var results = SystemDnsUtil.SetNameServers(nameServers);
this.logger.LogInformation($"设置本机dns成功");
return results;
SystemDnsUtil.DnsFlushResolverCache();
SystemDnsUtil.DnsRemovePrimitive(IPAddress.Loopback);
}
catch (Exception ex)
{
this.logger.LogWarning($"设置本机dns失败：{ex.Message}");
this.logger.LogWarning($"恢复DNS记录失败：{ex.Message}");
}
}
else
{
this.logger.LogWarning("不支持自动设置dns，请手动设置网卡的dns为127.0.0.1");
}
return default;
return base.StopAsync(cancellationToken);
}
}
}

79
FastGithub.Dns/SystemDnsUtil.cs
View File

@ -1,4 +1,5 @@
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Net;
@ -22,54 +23,85 @@ namespace FastGithub.Dns
[DllImport("iphlpapi")]
private static extern int GetBestInterface(uint dwDestAddr, ref uint pdwBestIfIndex);
/// <summary>
/// 刷新DNS缓存
/// </summary>
[DllImport("dnsapi.dll", EntryPoint = "DnsFlushResolverCache", SetLastError = true)]
public static extern void DnsFlushResolverCache();
/// <summary>
/// 通过远程地址查找匹配的网络适接口
/// </summary>
/// <param name="remoteAddress"></param>
/// <returns></returns>
private static NetworkInterface? GetBestNetworkInterface(IPAddress remoteAddress)
private static NetworkInterface GetBestNetworkInterface(IPAddress remoteAddress)
{
var dwBestIfIndex = 0u;
var dwDestAddr = BitConverter.ToUInt32(remoteAddress.GetAddressBytes());
var errorCode = GetBestInterface(dwDestAddr, ref dwBestIfIndex);
return errorCode != 0
? throw new NetworkInformationException(errorCode)
: NetworkInterface
if (errorCode != 0)
{
throw new NetworkInformationException(errorCode);
}
var @interface = NetworkInterface
.GetAllNetworkInterfaces()
.Where(item => item.GetIPProperties().GetIPv4Properties().Index == dwBestIfIndex)
.FirstOrDefault();
return @interface ?? throw new NotSupportedException("找不到网络适配器用来设置dns");
}
/// <summary>
/// 设置域名服务
/// 设置主dns
/// </summary>
/// <param name="nameServers"></param>
/// <param name="primitive"></param>
/// <exception cref="NetworkInformationException"></exception>
/// <exception cref="NotSupportedException"></exception>
/// <returns>未设置之前的记录</returns>
public static IPAddress[] SetNameServers(params IPAddress[] nameServers)
public static void DnsSetPrimitive(IPAddress primitive)
{
var networkInterface = GetBestNetworkInterface(www_baidu_com);
if (networkInterface == null)
var @interface = GetBestNetworkInterface(www_baidu_com);
var dnsAddresses = @interface.GetIPProperties().DnsAddresses;
if (primitive.Equals(dnsAddresses.FirstOrDefault()) == false)
{
throw new NotSupportedException("找不到网络适配器用来设置dns");
var nameServers = dnsAddresses.Prepend(primitive);
SetNameServers(@interface, nameServers);
}
var dnsAddresses = networkInterface.GetIPProperties().DnsAddresses.ToArray();
Netsh($@"interface ipv4 delete dns ""{networkInterface.Name}"" all");
foreach (var address in nameServers)
{
Netsh($@"interface ipv4 add dns ""{networkInterface.Name}"" {address} validate=no");
}
return dnsAddresses;
}
/// <summary>
/// 执行Netsh
/// 移除主dns
/// </summary>
/// <param name="arguments"></param>
private static void Netsh(string arguments)
/// <param name="primitive"></param>
/// <exception cref="NetworkInformationException"></exception>
/// <exception cref="NotSupportedException"></exception>
public static void DnsRemovePrimitive(IPAddress primitive)
{
var @interface = GetBestNetworkInterface(www_baidu_com);
var dnsAddresses = @interface.GetIPProperties().DnsAddresses;
if (primitive.Equals(dnsAddresses.FirstOrDefault()))
{
var nameServers = dnsAddresses.Skip(1);
SetNameServers(@interface, nameServers);
}
}
/// <summary>
/// 设置网口的dns
/// </summary>
/// <param name="interface"></param>
/// <param name="nameServers"></param>
private static void SetNameServers(NetworkInterface @interface, IEnumerable<IPAddress> nameServers)
{
Netsh($@"interface ipv4 delete dns ""{@interface.Name}"" all");
foreach (var address in nameServers)
{
Netsh($@"interface ipv4 add dns ""{@interface.Name}"" {address} validate=no");
}
static void Netsh(string arguments)
{
var netsh = new ProcessStartInfo
{
@ -82,4 +114,5 @@ namespace FastGithub.Dns
Process.Start(netsh)?.WaitForExit();
}
}
}
}