FastGithub/FastGithub.Dns/GithubRequestResolver.cs
2021-07-13 21:27:53 +08:00

87 lines
3.1 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.Linq;
using System.Net.Sockets;
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 IGithubScanResults githubScanResults;
private readonly IOptionsMonitor<DnsOptions> options;
private readonly ILogger<GithubRequestResolver> logger;
/// <summary>
/// github相关域名解析器
/// </summary>
/// <param name="githubScanResults"></param>
/// <param name="options"></param>
/// <param name="logger"></param>
public GithubRequestResolver(
IGithubScanResults githubScanResults,
IOptionsMonitor<DnsOptions> options,
ILogger<GithubRequestResolver> logger)
{
this.githubScanResults = githubScanResults;
this.options = options;
this.logger = logger;
}
/// <summary>
/// 解析域名
/// </summary>
/// <param name="request"></param>
/// <param name="cancellationToken"></param>
/// <returns></returns>
public async Task<IResponse> Resolve(IRequest request, CancellationToken cancellationToken = default)
{
var response = Response.FromRequest(request);
var question = request.Questions.FirstOrDefault();
if (question != null && question.Type == RecordType.A)
{
var domain = question.Name.ToString();
var address = this.githubScanResults.FindBestAddress(domain);
if (address != null)
{
var ttl = this.options.CurrentValue.GithubTTL;
if (this.options.CurrentValue.UseReverseProxy == false)
{
var record = new IPAddressResourceRecord(question.Name, address, ttl);
response.AnswerRecords.Add(record);
this.logger.LogInformation(record.ToString());
}
else
{
var hostName = System.Net.Dns.GetHostName();
var addresses = await System.Net.Dns.GetHostAddressesAsync(hostName);
foreach (var item in addresses)
{
if (item.AddressFamily == AddressFamily.InterNetwork)
{
var record = new IPAddressResourceRecord(question.Name, item, ttl);
response.AnswerRecords.Add(record);
this.logger.LogInformation(record.ToString());
}
}
}
}
}
return response;
}
}
}