完善dns配置检测

FastGithub.Core/DnsIPEndPoint.cs

@@ -1,5 +1,6 @@
 using System.Diagnostics.CodeAnalysis;
 using System.Net;
+using System.Net.NetworkInformation;
 
 namespace FastGithub
 {
@@ -29,14 +30,43 @@ namespace FastGithub
         }
 
         /// <summary>
-        /// 验证
+        /// 验证dns
+        /// 防止使用自己使用自己来解析域名造成死循环
         /// </summary>
         /// <returns></returns>
         public bool Validate()
         {
-            return System.Net.IPAddress.TryParse(this.IPAddress, out var address)
-                ? !(address.Equals(System.Net.IPAddress.Loopback) && this.Port == 53)
-                : false;
+            if (System.Net.IPAddress.TryParse(this.IPAddress, out var address) == false)
+            {
+                return false;
+            }
+
+            if (this.Port == 53 && IsLocalMachineIPAddress(address))
+            {
+                return false;
+            }
+
+            return true;
+        }
+
+        /// <summary>
+        /// 是否为本机ip
+        /// </summary>
+        /// <param name="address"></param>
+        /// <returns></returns>
+        private static bool IsLocalMachineIPAddress(IPAddress address)
+        {
+            foreach (var @interface in NetworkInterface.GetAllNetworkInterfaces())
+            {
+                foreach (var addressInfo in @interface.GetIPProperties().UnicastAddresses)
+                {
+                    if (addressInfo.Address.Equals(address))
+                    {
+                        return true;
+                    }
+                }
+            }
+            return false;
         }
     }
 }

FastGithub.ReverseProxy/DomainResolver.cs

@@ -12,7 +12,7 @@ namespace FastGithub.ReverseProxy
     /// <summary>
     /// 受信任的域名解析器
     /// </summary> 
-    sealed class TrustedResolver
+    sealed class DomainResolver
     {
         private readonly IMemoryCache memoryCache;
         private readonly TimeSpan cacheTimeSpan = TimeSpan.FromSeconds(10d);
@@ -22,7 +22,7 @@ namespace FastGithub.ReverseProxy
         /// 受信任的域名解析器
         /// </summary> 
         /// <param name="options"></param>
-        public TrustedResolver(
+        public DomainResolver(
             IMemoryCache memoryCache,
             IOptionsMonitor<FastGithubOptions> options)
         {
@@ -66,6 +66,7 @@ namespace FastGithub.ReverseProxy
                     throw new Exception($"解析不到{domain}的ip");
                 }
 
+                // 受干扰的dns，常常返回127.0.0.1来阻断请求
                 // 如果解析到的ip为本机ip，会产生反向代理请求死循环
                 if (address.Equals(IPAddress.Loopback))
                 {

FastGithub.ReverseProxy/NoSniHttpClientHanlder.cs

@@ -13,7 +13,7 @@ namespace FastGithub.ReverseProxy
     /// </summary> 
     class NoSniHttpClientHanlder : DelegatingHandler
     {
-        private readonly TrustedResolver trustedDomainResolver;
+        private readonly DomainResolver trustedDomainResolver;
         private readonly ILogger<NoSniHttpClientHanlder> logger;
 
         /// <summary>
@@ -21,7 +21,7 @@ namespace FastGithub.ReverseProxy
         /// </summary>
         /// <param name="trustedDomainResolver"></param> 
         public NoSniHttpClientHanlder(
-            TrustedResolver trustedDomainResolver,
+            DomainResolver trustedDomainResolver,
             ILogger<NoSniHttpClientHanlder> logger)
         {
             this.trustedDomainResolver = trustedDomainResolver;

FastGithub.ReverseProxy/ReverseProxyServiceCollectionExtensions.cs

@@ -18,7 +18,7 @@ namespace FastGithub
             return services
                 .AddMemoryCache()
                 .AddHttpForwarder()
-                .AddSingleton<TrustedResolver>()
+                .AddSingleton<DomainResolver>()
                 .AddTransient<NoSniHttpClientHanlder>();
         }
     }