using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using System;
using System.Collections.Generic;
using System.Net;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
namespace FastGithub.Dns
{
///
/// dns后台服务
///
sealed class DnsOverUdpHostedService : BackgroundService
{
private readonly DnsOverUdpServer dnsOverUdpServer;
private readonly IEnumerable conflictValidators;
private readonly ILogger logger;
///
/// dns后台服务
///
///
///
///
public DnsOverUdpHostedService(
DnsOverUdpServer dnsOverUdpServer,
IEnumerable conflictValidators,
ILogger logger)
{
this.dnsOverUdpServer = dnsOverUdpServer;
this.conflictValidators = conflictValidators;
this.logger = logger;
}
///
/// 启动dns
///
///
///
public override async Task StartAsync(CancellationToken cancellationToken)
{
try
{
const int DNS_PORT = 53;
this.dnsOverUdpServer.Listen(IPAddress.Any, DNS_PORT);
this.logger.LogInformation($"已监听udp端口{DNS_PORT},DNS服务启动完成");
}
catch (Exception ex)
{
var builder = new StringBuilder().AppendLine($"DNS服务启动失败({ex.Message}),你可以选择如下的一种操作:");
builder.AppendLine($"1. 关闭占用udp53端口的进程然后重新打开本程序");
builder.AppendLine($"2. 配置系统或浏览器使用DNS over HTTPS:https://127.0.0.1/dns-query");
builder.AppendLine($"3. 向系统hosts文件添加github相关域名的ip为127.0.0.1");
builder.Append($"4. 在局域网其它设备上运行本程序,然后将本机DNS设置为局域网设备的IP");
this.logger.LogError(builder.ToString());
}
foreach (var item in this.conflictValidators)
{
await item.ValidateAsync();
}
await base.StartAsync(cancellationToken);
}
///
/// dns后台
///
///
///
protected override Task ExecuteAsync(CancellationToken stoppingToken)
{
return this.dnsOverUdpServer.HandleAsync(stoppingToken);
}
///
/// 停止dns服务
///
///
///
public override Task StopAsync(CancellationToken cancellationToken)
{
this.dnsOverUdpServer.Dispose();
return base.StopAsync(cancellationToken);
}
}
}