85 lines
2.8 KiB
C#
85 lines
2.8 KiB
C#
using DNS.Client.RequestResolver;
|
|
using DNS.Protocol;
|
|
using DNS.Protocol.ResourceRecords;
|
|
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>
|
|
/// dns解析者
|
|
/// </summary>
|
|
sealed class RequestResolver : IRequestResolver
|
|
{
|
|
private IRequestResolver requestResolver;
|
|
|
|
private readonly TimeSpan ttl = TimeSpan.FromMinutes(1d);
|
|
private readonly FastGithubConfig fastGithubConfig;
|
|
private readonly ILogger<RequestResolver> logger;
|
|
|
|
/// <summary>
|
|
/// dns解析者
|
|
/// </summary>
|
|
/// <param name="fastGithubConfig"></param>
|
|
/// <param name="options"></param>
|
|
/// <param name="logger"></param>
|
|
public RequestResolver(
|
|
FastGithubConfig fastGithubConfig,
|
|
IOptionsMonitor<FastGithubOptions> options,
|
|
ILogger<RequestResolver> logger)
|
|
{
|
|
this.fastGithubConfig = fastGithubConfig;
|
|
this.logger = logger;
|
|
|
|
this.requestResolver = new UdpRequestResolver(fastGithubConfig.FastDns);
|
|
options.OnChange(opt => OptionsChanged(opt));
|
|
|
|
void OptionsChanged(FastGithubOptions opt)
|
|
{
|
|
var dns = opt.FastDns.ToIPEndPoint();
|
|
this.requestResolver = new UdpRequestResolver(dns);
|
|
}
|
|
}
|
|
|
|
/// <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);
|
|
if (request is not RemoteEndPointRequest remoteEndPointRequest)
|
|
{
|
|
return response;
|
|
}
|
|
|
|
var question = request.Questions.FirstOrDefault();
|
|
if (question == null || question.Type != RecordType.A)
|
|
{
|
|
return response;
|
|
}
|
|
|
|
// 解析匹配的域名指向本机ip
|
|
var domain = question.Name;
|
|
if (this.fastGithubConfig.IsMatch(domain.ToString()) == true)
|
|
{
|
|
var localAddress = remoteEndPointRequest.GetLocalAddress() ?? IPAddress.Loopback;
|
|
var record = new IPAddressResourceRecord(domain, localAddress, this.ttl);
|
|
response.AnswerRecords.Add(record);
|
|
|
|
this.logger.LogInformation($"[{domain}->{localAddress}]");
|
|
return response;
|
|
}
|
|
|
|
return await this.requestResolver.Resolve(request, cancellationToken);
|
|
}
|
|
}
|
|
}
|