FastGithub/FastGithub.Dns/RequestResolver.cs
2021-07-27 20:46:48 +08:00

73 lines
2.4 KiB
C#

using DNS.Client.RequestResolver;
using DNS.Protocol;
using DNS.Protocol.ResourceRecords;
using FastGithub.Configuration;
using Microsoft.Extensions.Logging;
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 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="logger"></param>
public RequestResolver(
FastGithubConfig fastGithubConfig,
ILogger<RequestResolver> logger)
{
this.fastGithubConfig = fastGithubConfig;
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);
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;
}
var fastResolver = new UdpRequestResolver(fastGithubConfig.FastDns);
return await fastResolver.Resolve(request, cancellationToken);
}
}
}