116 lines
4.0 KiB
C#
116 lines
4.0 KiB
C#
using DNS.Client.RequestResolver;
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using DNS.Protocol;
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using DNS.Protocol.ResourceRecords;
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using FastGithub.ReverseProxy;
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using FastGithub.Scanner;
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using Microsoft.Extensions.DependencyInjection;
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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.Linq;
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using System.Net;
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using System.Net.Sockets;
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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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/// github相关域名解析器
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/// </summary>
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[Service(ServiceLifetime.Singleton)]
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sealed class GithubRequestResolver : IRequestResolver
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{
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private readonly IGithubScanResults githubScanResults;
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private readonly IOptionsMonitor<DnsOptions> options;
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private readonly IOptionsMonitor<GithubReverseProxyOptions> reverseProxyOptions;
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private readonly ILogger<GithubRequestResolver> logger;
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/// <summary>
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/// github相关域名解析器
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/// </summary>
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/// <param name="githubScanResults"></param>
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/// <param name="options"></param>
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/// <param name="logger"></param>
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public GithubRequestResolver(
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IGithubScanResults githubScanResults,
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IOptionsMonitor<DnsOptions> options,
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IOptionsMonitor<GithubReverseProxyOptions> reverseProxyOptions,
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ILogger<GithubRequestResolver> logger)
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{
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this.githubScanResults = githubScanResults;
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this.options = options;
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this.reverseProxyOptions = reverseProxyOptions;
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this.logger = logger;
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}
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/// <summary>
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/// 解析域名
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/// </summary>
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/// <param name="request"></param>
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/// <param name="cancellationToken"></param>
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/// <returns></returns>
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public async Task<IResponse> Resolve(IRequest request, CancellationToken cancellationToken = default)
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{
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var response = Response.FromRequest(request);
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var question = request.Questions.FirstOrDefault();
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if (question == null || question.Type != RecordType.A)
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{
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return response;
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}
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var domain = question.Name.ToString();
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if (this.githubScanResults.Support(domain) == false)
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{
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return response;
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}
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if (this.reverseProxyOptions.CurrentValue.Enable == false)
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{
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var address = this.githubScanResults.FindBestAddress(domain);
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if (address != null)
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{
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var ttl = this.options.CurrentValue.GithubTTL;
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var record = new IPAddressResourceRecord(question.Name, address, ttl);
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response.AnswerRecords.Add(record);
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this.logger.LogInformation($"[{domain}->{address}]");
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}
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}
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else
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{
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var address = await GetLocalHostAddress();
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var record = new IPAddressResourceRecord(question.Name, address, TimeSpan.FromMinutes(1));
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response.AnswerRecords.Add(record);
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this.logger.LogInformation($"[{domain}->{address}]");
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}
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if (response.AnswerRecords.Count == 0)
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{
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this.logger.LogWarning($"无法获得{domain}的最快ip");
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}
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return response;
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}
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/// <summary>
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/// 获取本机ip
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/// </summary>
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/// <returns></returns>
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private static async Task<IPAddress> GetLocalHostAddress()
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{
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try
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{
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var localhost = System.Net.Dns.GetHostName();
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var addresses = await System.Net.Dns.GetHostAddressesAsync(localhost);
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var address = addresses.FirstOrDefault(item => item.AddressFamily == AddressFamily.InterNetwork);
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return address ?? IPAddress.Loopback;
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}
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catch (Exception)
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{
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return IPAddress.Loopback;
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}
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}
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}
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}
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