FastGithub/FastGithub.Dns/GithubRequestResolver.cs
2021-07-15 13:53:49 +08:00

86 lines
3.0 KiB
C#

using DNS.Client.RequestResolver;
using DNS.Protocol;
using DNS.Protocol.ResourceRecords;
using FastGithub.Scanner;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using System;
using System.Linq;
using System.Net;
using System.Threading;
using System.Threading.Tasks;
namespace FastGithub.Dns
{
/// <summary>
/// github相关域名解析器
/// </summary>
[Service(ServiceLifetime.Singleton)]
sealed class GithubRequestResolver : IRequestResolver
{
private readonly IGithubResolver githubResolver;
private readonly IOptionsMonitor<DnsOptions> options;
private readonly ILogger<GithubRequestResolver> logger;
/// <summary>
/// github相关域名解析器
/// </summary>
/// <param name="githubResolver"></param>
/// <param name="options"></param>
/// <param name="logger"></param>
public GithubRequestResolver(
IGithubResolver githubResolver,
IOptionsMonitor<DnsOptions> options,
ILogger<GithubRequestResolver> logger)
{
this.githubResolver = githubResolver;
this.options = options;
this.logger = logger;
}
/// <summary>
/// 解析域名
/// </summary>
/// <param name="request"></param>
/// <param name="cancellationToken"></param>
/// <returns></returns>
public Task<IResponse> Resolve(IRequest request, CancellationToken cancellationToken = default)
{
IResponse response = Response.FromRequest(request);
var question = request.Questions.FirstOrDefault();
if (question == null || question.Type != RecordType.A)
{
return Task.FromResult(response);
}
var domain = question.Name.ToString();
if (this.githubResolver.IsSupported(domain) == false)
{
return Task.FromResult(response);
}
if (this.options.CurrentValue.UseGithubReverseProxy == false)
{
var address = this.githubResolver.Resolve(domain);
if (address != null)
{
var ttl = this.options.CurrentValue.GithubTTL;
var record = new IPAddressResourceRecord(question.Name, address, ttl);
response.AnswerRecords.Add(record);
this.logger.LogInformation($"[{domain}->{address}]");
}
}
else
{
var address = IPAddress.Parse(this.options.CurrentValue.GithubReverseProxyIPAddress);
var record = new IPAddressResourceRecord(question.Name, address, TimeSpan.FromMinutes(1));
response.AnswerRecords.Add(record);
this.logger.LogInformation($"[{domain}->{address}]");
}
return Task.FromResult(response);
}
}
}