Add unit tests for DOSGuard (#453)

Fixes #452

unittests/DOSGuard.cpp

@@ -0,0 +1,152 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of clio: https://github.com/XRPLF/clio
+    Copyright (c) 2022, the clio developers.
+
+    Permission to use, copy, modify, and distribute this software for any
+    purpose with or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
+    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY  SPECIAL,  DIRECT,  INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+//==============================================================================
+
+#include <util/Fixtures.h>
+
+#include <config/Config.h>
+#include <webserver/DOSGuard.h>
+
+#include <boost/json/parse.hpp>
+#include <gmock/gmock.h>
+
+using namespace testing;
+using namespace clio;
+using namespace std;
+namespace json = boost::json;
+
+namespace {
+constexpr static auto JSONData = R"JSON(
+    {
+        "dos_guard": {
+            "max_fetches": 100,
+            "sweep_interval": 1,
+            "max_connections": 2,
+            "whitelist": ["127.0.0.1"]
+        }
+    }
+)JSON";
+
+constexpr static auto JSONData2 = R"JSON(
+    {
+        "dos_guard": {
+            "max_fetches": 100,
+            "sweep_interval": 0.1,
+            "max_connections": 2,
+            "whitelist": ["127.0.0.1"]
+        }
+    }
+)JSON";
+
+constexpr static auto IP = "127.0.0.2";
+
+class FakeSweepHandler
+{
+private:
+    using guard_type = BasicDOSGuard<FakeSweepHandler>;
+    guard_type* dosGuard_;
+
+public:
+    void
+    setup(guard_type* guard)
+    {
+        dosGuard_ = guard;
+    }
+
+    void
+    sweep()
+    {
+        dosGuard_->clear();
+    }
+};
+};  // namespace
+
+class DOSGuardTest : public NoLoggerFixture
+{
+protected:
+    Config cfg{json::parse(JSONData)};
+    FakeSweepHandler sweepHandler;
+    BasicDOSGuard<FakeSweepHandler> guard{cfg, sweepHandler};
+};
+
+TEST_F(DOSGuardTest, Whitelisting)
+{
+    EXPECT_TRUE(guard.isWhiteListed("127.0.0.1"));
+    EXPECT_FALSE(guard.isWhiteListed(IP));
+}
+
+TEST_F(DOSGuardTest, ConnectionCount)
+{
+    EXPECT_TRUE(guard.isOk(IP));
+    guard.increment(IP);  // one connection
+    EXPECT_TRUE(guard.isOk(IP));
+    guard.increment(IP);  // two connections
+    EXPECT_TRUE(guard.isOk(IP));
+    guard.increment(IP);  // > two connections, can't connect more
+    EXPECT_FALSE(guard.isOk(IP));
+
+    guard.decrement(IP);
+    EXPECT_TRUE(guard.isOk(IP));  // can connect again
+}
+
+TEST_F(DOSGuardTest, FetchCount)
+{
+    EXPECT_TRUE(guard.add(IP, 50));  // half of allowence
+    EXPECT_TRUE(guard.add(IP, 50));  // now fully charged
+    EXPECT_FALSE(guard.add(IP, 1));  // can't add even 1 anymore
+    EXPECT_FALSE(guard.isOk(IP));
+
+    guard.clear();                // force clear the above fetch count
+    EXPECT_TRUE(guard.isOk(IP));  // can fetch again
+}
+
+TEST_F(DOSGuardTest, ClearFetchCountOnTimer)
+{
+    EXPECT_TRUE(guard.add(IP, 50));  // half of allowence
+    EXPECT_TRUE(guard.add(IP, 50));  // now fully charged
+    EXPECT_FALSE(guard.add(IP, 1));  // can't add even 1 anymore
+    EXPECT_FALSE(guard.isOk(IP));
+
+    sweepHandler.sweep();         // pretend sweep called from timer
+    EXPECT_TRUE(guard.isOk(IP));  // can fetch again
+}
+
+template <typename SweepHandler>
+struct BasicDOSGuardMock : public BaseDOSGuard
+{
+    BasicDOSGuardMock(SweepHandler& handler)
+    {
+        handler.setup(this);
+    }
+
+    MOCK_METHOD(void, clear, (), (noexcept, override));
+};
+
+class DOSGuardIntervalSweepHandlerTest : public SyncAsioContextTest
+{
+protected:
+    Config cfg{json::parse(JSONData2)};
+    IntervalSweepHandler sweepHandler{cfg, ctx};
+    BasicDOSGuardMock<IntervalSweepHandler> guard{sweepHandler};
+};
+
+TEST_F(DOSGuardIntervalSweepHandlerTest, SweepAfterInterval)
+{
+    EXPECT_CALL(guard, clear()).Times(Exactly(2));
+    ctx.run_for(std::chrono::milliseconds(210));
+}

unittests/util/Fixtures.h

@@ -21,6 +21,9 @@
 
 #include <ios>
 #include <mutex>
+#include <thread>
+
+#include <boost/asio.hpp>
 
 #include <gtest/gtest.h>
 #include <log/Logger.h>
@@ -107,3 +110,46 @@ protected:
         boost::log::core::get()->set_logging_enabled(false);
     }
 };
+
+/**
+ * @brief Fixture with an embedded boost::asio context running on a thread
+ *
+ * This is meant to be used as a base for other fixtures.
+ */
+struct AsyncAsioContextTest : public NoLoggerFixture
+{
+    AsyncAsioContextTest()
+    {
+        work.emplace(ctx);  // make sure ctx does not stop on its own
+    }
+
+    ~AsyncAsioContextTest()
+    {
+        work.reset();
+        ctx.stop();
+    }
+
+protected:
+    boost::asio::io_context ctx;
+
+private:
+    std::optional<boost::asio::io_service::work> work;
+    std::jthread runner{[this] { ctx.run(); }};
+};
+
+/**
+ * @brief Fixture with an embedded boost::asio context that is not running by
+ * default but can be progressed on the calling thread
+ *
+ * Use `run_for(duration)` etc. directly on `ctx`.
+ * This is meant to be used as a base for other fixtures.
+ */
+struct SyncAsioContextTest : public NoLoggerFixture
+{
+    SyncAsioContextTest()
+    {
+    }
+
+protected:
+    boost::asio::io_context ctx;
+};