118 lines
3.7 KiB
C#
118 lines
3.7 KiB
C#
using FastGithub.Configuration;
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using Microsoft.Extensions.Hosting;
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using Microsoft.Extensions.Logging;
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using Microsoft.Extensions.Options;
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using System;
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using System.Collections.Generic;
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using System.Net;
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using System.Threading;
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using System.Threading.Tasks;
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namespace FastGithub.Dns
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{
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/// <summary>
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/// dns后台服务
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/// </summary>
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sealed class DnsOverUdpHostedService : BackgroundService
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{
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private readonly DnsOverUdpServer dnsOverUdpServer;
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private readonly IEnumerable<IConflictValidator> conflictValidators;
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private readonly IOptionsMonitor<FastGithubOptions> options;
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private readonly ILogger<DnsOverUdpHostedService> logger;
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/// <summary>
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/// dns后台服务
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/// </summary>
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/// <param name="dnsOverUdpServer"></param>
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/// <param name="conflictValidators"></param>
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/// <param name="options"></param>
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/// <param name="logger"></param>
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public DnsOverUdpHostedService(
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DnsOverUdpServer dnsOverUdpServer,
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IEnumerable<IConflictValidator> conflictValidators,
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IOptionsMonitor<FastGithubOptions> options,
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ILogger<DnsOverUdpHostedService> logger)
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{
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this.dnsOverUdpServer = dnsOverUdpServer;
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this.conflictValidators = conflictValidators;
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this.options = options;
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this.logger = logger;
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options.OnChange(opt => SystemDnsUtil.FlushResolverCache());
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}
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/// <summary>
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/// 启动dns
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/// </summary>
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/// <param name="cancellationToken"></param>
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/// <returns></returns>
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public override async Task StartAsync(CancellationToken cancellationToken)
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{
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var dnsPort = this.options.CurrentValue.Listen.DnsPort;
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this.dnsOverUdpServer.Bind(IPAddress.Any, dnsPort);
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this.logger.LogInformation($"已监听udp端口{dnsPort}，DNS服务启动完成");
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const int STANDARD_DNS_PORT = 53;
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if (dnsPort == STANDARD_DNS_PORT)
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{
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try
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{
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SystemDnsUtil.SetAsPrimitiveDns();
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SystemDnsUtil.FlushResolverCache();
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}
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catch (Exception ex)
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{
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this.logger.LogWarning(ex.Message);
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}
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}
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else
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{
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this.logger.LogWarning($"由于使用了非标准DNS端口{dnsPort}，你需要将{nameof(FastGithub)}设置为标准DNS的上游");
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}
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foreach (var item in this.conflictValidators)
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{
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await item.ValidateAsync();
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}
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await base.StartAsync(cancellationToken);
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}
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/// <summary>
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/// dns后台
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/// </summary>
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/// <param name="stoppingToken"></param>
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/// <returns></returns>
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protected override Task ExecuteAsync(CancellationToken stoppingToken)
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{
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return this.dnsOverUdpServer.HandleAsync(stoppingToken);
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}
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/// <summary>
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/// 停止dns服务
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/// </summary>
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/// <param name="cancellationToken"></param>
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/// <returns></returns>
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public override Task StopAsync(CancellationToken cancellationToken)
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{
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this.dnsOverUdpServer.Dispose();
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this.logger.LogInformation("DNS服务已停止");
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try
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{
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SystemDnsUtil.RemoveFromPrimitiveDns();
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}
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catch (Exception ex)
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{
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this.logger.LogWarning(ex.Message);
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}
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finally
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{
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SystemDnsUtil.FlushResolverCache();
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}
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return base.StopAsync(cancellationToken);
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}
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}
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}
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