add RateLimiter class

CMakeLists.txt

@@ -35,6 +35,7 @@ set(PRJ_HEADERS
     include/Json.h
     include/LuaAPI.h
     include/RWMutex.h
+    include/RateLimiter.h
     include/SignalHandling.h
     include/TConfig.h
     include/TConsole.h
@@ -72,6 +73,7 @@ set(PRJ_SOURCES
     src/TResourceManager.cpp
     src/TScopedTimer.cpp
     src/TServer.cpp
+    src/RateLimiter.cpp
     src/VehicleData.cpp
     src/Env.cpp
     src/Profiling.cpp

include/RateLimiter.h

@@ -0,0 +1,20 @@
+#include "Common.h"
+#include <chrono>
+#include <fstream>
+#include <iostream>
+#include <mutex>
+#include <unordered_map>
+#include <unordered_set>
+
+class RateLimiter {
+public:
+    RateLimiter();
+    bool isConnectionAllowed(const std::string& client_address);
+
+private:
+    std::unordered_map<std::string, std::vector<std::chrono::time_point<std::chrono::high_resolution_clock>>> m_connection;
+    std::mutex m_connection_mutex;
+
+    void blockIP(const std::string& client_address);
+    bool isIPBlocked(const std::string& client_address);
+};

include/TNetwork.h

@@ -48,7 +48,6 @@ public:
 private:
     void UDPServerMain();
     void TCPServerMain();
-
     TServer& mServer;
     TPPSMonitor& mPPSMonitor;
     ip::udp::socket mUDPSock;

src/RateLimiter.cpp

@@ -0,0 +1,50 @@
+#include "RateLimiter.h"
+
+RateLimiter::RateLimiter() {};
+
+bool RateLimiter::isConnectionAllowed(const std::string& client_address) {
+    if (RateLimiter::isIPBlocked(client_address)) {
+        return false;
+    }
+    std::lock_guard<std::mutex> lock(m_connection_mutex);
+    auto current_time = std::chrono::high_resolution_clock::now();
+    auto& violations = m_connection[client_address];
+
+    // Deleting old violations (older than 5 seconds)
+    violations.erase(std::remove_if(violations.begin(), violations.end(),
+                         [&](const auto& timestamp) {
+                             return std::chrono::duration_cast<std::chrono::seconds>(current_time - timestamp).count() > 5;
+                         }),
+        violations.end());
+
+    violations.push_back(current_time);
+
+    if (violations.size() >= 4) {
+        RateLimiter::blockIP(client_address);
+        beammp_errorf("[DoS Protection] Client with the IP: {} surpassed the violation treshhold and is now on the blocked list", client_address);
+        return false;
+    }
+
+    return true; // We allow the connection
+}
+
+void RateLimiter::blockIP(const std::string& client_address) {
+    std::ofstream block_file("blocked_ips.txt", std::ios::app);
+    if (block_file.is_open()) {
+        block_file << client_address << std::endl;
+    }
+}
+
+bool RateLimiter::isIPBlocked(const std::string& client_address) {
+    std::ifstream block_file("blocked_ips.txt");
+    std::unordered_set<std::string> blockedIPs;
+
+    if (block_file.is_open()) {
+        std::string line;
+        while (std::getline(block_file, line)) {
+            blockedIPs.insert(line);
+        }
+    }
+
+    return blockedIPs.contains(client_address);
+};

src/TNetwork.cpp

@@ -20,6 +20,7 @@
 #include "Client.h"
 #include "Common.h"
 #include "LuaAPI.h"
+#include "RateLimiter.h"
 #include "TLuaEngine.h"
 #include "nlohmann/json.hpp"
 #include <CustomAssert.h>
@@ -196,10 +197,18 @@ void TNetwork::Identify(TConnection&& RawConnection) {
         RawConnection.Socket.shutdown(socket_base::shutdown_both, ec);
         return;
     }
-    std::shared_ptr<TClient> Client { nullptr };
+    std::string client_address = RawConnection.SockAddr.address().to_string();
+    std::shared_ptr<TClient> client { nullptr };
+    RateLimiter ddos_protection;
     try {
         if (Code == 'C') {
-            Client = Authentication(std::move(RawConnection));
+            if (ddos_protection.isConnectionAllowed(client_address)) {
+                beammp_infof("[DoS Protection] Client: [{}] is authorized to connect to the server", client_address);
+                client = Authentication(std::move(RawConnection));
+            } else {
+                beammp_infof("[DoS Protection] Client: [{}] has been denied access to the server", client_address);
+                RawConnection.Socket.shutdown(socket_base::shutdown_both, ec);
+            }
         } else if (Code == 'D') {
             HandleDownload(std::move(RawConnection));
         } else if (Code == 'P') {
@@ -389,7 +398,7 @@ std::shared_ptr<TClient> TNetwork::Authentication(TConnection&& RawConnection) {
             return false;
         });
 
-    if (!NotAllowedWithReason && !Application::Settings.AllowGuests && Client->IsGuest()) { //!NotAllowedWithReason because this message has the lowest priority
+    if (!NotAllowedWithReason && !Application::Settings.AllowGuests && Client->IsGuest()) { //! NotAllowedWithReason because this message has the lowest priority
         NotAllowedWithReason = true;
         Reason = "No guests are allowed on this server! To join, sign up at: forum.beammp.com.";
     }