Initial upload

Middleware/VPNBlockMiddleware.cs

@@ -0,0 +1,156 @@
+using Microsoft.AspNetCore.Http;
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Net;
+using System.Net.Http;
+using System.Text.Json;
+using System.Threading.Tasks;
+
+public class VpnBlockMiddleware
+{
+    private static readonly HttpClient Http = new HttpClient
+    {
+        Timeout = TimeSpan.FromSeconds(5)
+    };
+
+    private static readonly string DataPath = Path.Combine(Environment.CurrentDirectory, "Data");
+    private static readonly string CacheFile = Path.Combine(DataPath, "Ips.json");
+
+    private static readonly List<IpCacheEntry> IpCache;
+
+    private readonly RequestDelegate _next;
+
+    static VpnBlockMiddleware()
+    {
+        Http.DefaultRequestHeaders.UserAgent.ParseAdd(
+            "Mozilla/5.0 (Windows NT 10.0; Win64; x64)");
+
+        // Ensure Data folder exists
+        if (!Directory.Exists(DataPath))
+            Directory.CreateDirectory(DataPath);
+
+        // Load or initialize cache
+        if (File.Exists(CacheFile))
+        {
+            var json = File.ReadAllText(CacheFile);
+            try
+            {
+                IpCache = JsonSerializer.Deserialize<List<IpCacheEntry>>(json) ?? new List<IpCacheEntry>();
+            }
+            catch
+            {
+                IpCache = new List<IpCacheEntry>();
+            }
+        }
+        else
+        {
+            IpCache = new List<IpCacheEntry>();
+        }
+    }
+
+    public VpnBlockMiddleware(RequestDelegate next)
+    {
+        _next = next;
+    }
+
+    public async Task InvokeAsync(HttpContext context)
+    {
+        string? ip = context.Request.Headers["CF-Connecting-IP"].FirstOrDefault()
+        ?? context.Request.Headers["X-Forwarded-For"].FirstOrDefault()
+        ?? context.Connection.RemoteIpAddress?.ToString();
+
+        if (ip == null)
+        {
+            context.Response.StatusCode = StatusCodes.Status403Forbidden;
+            await context.Response.WriteAsync("???");
+            return;
+        }
+
+        string ipStr = ip.ToString();
+
+        // ---------- VPN CHECK START ----------
+
+        // Check cache first
+        var cached = IpCache.Find(x => x.Ip == ipStr);
+        if (cached != null)
+        {
+            if (cached.IsVpn)
+            {
+                context.Response.StatusCode = StatusCodes.Status403Forbidden;
+                await context.Response.WriteAsync("You have been blocked due to being suspicious.");
+                return;
+            }
+            else
+            {
+                await _next(context);
+                return;
+            }
+        }
+
+        // Not in cache fetch from web
+        bool isVpn = true;
+        try
+        {
+            var url = $"https://whatismyipaddress.com/ip/{ipStr}";
+
+            var request = new HttpRequestMessage(HttpMethod.Get, url);
+
+            // Set all headers to mimic real browser
+            request.Headers.Add("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7");
+            request.Headers.Add("Accept-Encoding", "gzip, deflate, br, zstd");
+            request.Headers.Add("Accept-Language", "en-US,en;q=0.9");
+            request.Headers.Add("Cache-Control", "no-cache");
+            request.Headers.Add("Cookie", "_omappvp=gVm5QIhYs7ZPribnnBc5i0hcLYpksUDiKmaUjnC3eJDngY1GqHDK9X9VZ6X6YjdGJOIEopJi4PrOdRMf9FdpCTgsbQBQd8NA; usprivacy=1N--; pt=3f72ce96ed0863ed93f8e4f35cd5c051; cf_clearance=E.lrd8juQIWkUqgGOEu9IK1D7hj4VjU9MrKMu3ndw.Q-1768983651-1.2.1.1-yatNw.jMPyw7hUdlaVTRBwLPNS3zrTyJYuJP7WZ5cMC_JU1QcPOxxCSj.BIc6n9gYQlDTuu3MIeDohOS.dF.GzEY6SroaJJRS3Kqz.bSs2HmGA8WiDdMZ585PG47Sngr2MFufhyaQUejsCs62g3Xn5TNQW6ScnFH.SwZ_4_ltZrdvu7pYtu3SrGQC8rWvhyHgR_6DJJ8BM64SeF8zIL9ghgA4e0cSmp3q63JijsJb_I; _awl=2.1768987486.5-5aef88a3ad28e1513eae2c6b9b05ea1e-6763652d75732d7765737431-1");
+            request.Headers.Add("Pragma", "no-cache");
+            request.Headers.Add("Priority", "u=0, i");
+            request.Headers.Add("Sec-CH-UA", "\"Google Chrome\";v=\"143\", \"Chromium\";v=\"143\", \"Not A(Brand\";v=\"24\"");
+            request.Headers.Add("Sec-CH-UA-Mobile", "?0");
+            request.Headers.Add("Sec-CH-UA-Platform", "\"Windows\"");
+            request.Headers.Add("Sec-Fetch-Dest", "document");
+            request.Headers.Add("Sec-Fetch-Mode", "navigate");
+            request.Headers.Add("Sec-Fetch-Site", "none");
+            request.Headers.Add("Sec-Fetch-User", "?1");
+            request.Headers.Add("Upgrade-Insecure-Requests", "1");
+            request.Headers.Add("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/143.0.0.0 Safari/537.36");
+
+            var response = await Http.SendAsync(request);
+            if (!response.IsSuccessStatusCode)
+            {
+                Console.WriteLine($"[VPNBlockMiddleware] Failed to fetch IP info {ipStr}, status {response.StatusCode}");
+                isVpn = true; // fail-closed
+            }
+            else
+            {
+                var html = await response.Content.ReadAsStringAsync();
+                isVpn = !html.Contains("Services:</span><span>None detected", StringComparison.OrdinalIgnoreCase);
+            }
+        }
+        catch (Exception ex)
+        {
+            Console.WriteLine($"[VPNBlockMiddleware] Error checking IP {ipStr}: {ex.Message}");
+            isVpn = false; // fail-closed
+        }
+
+        // Save to cache
+        IpCache.Add(new IpCacheEntry { Ip = ipStr, IsVpn = isVpn });
+        File.WriteAllText(CacheFile, JsonSerializer.Serialize(IpCache, new JsonSerializerOptions { WriteIndented = false }));
+
+        if (isVpn)
+        {
+            context.Response.StatusCode = StatusCodes.Status403Forbidden;
+            await context.Response.WriteAsync("You have been blocked due to being suspicious.");
+            return;
+        }
+
+        // ---------- VPN CHECK END ----------
+
+        await _next(context);
+    }
+
+    private class IpCacheEntry
+    {
+        public string Ip { get; set; } = "";
+        public bool IsVpn { get; set; }
+    }
+}