feat: SKSE & MO2 policies.

Code/client/ScriptExtender.cpp

@@ -19,6 +19,8 @@ constexpr size_t kScriptExtenderNameLength = sizeof(kScriptExtenderName) / sizeo
 // Use this to raise the SKSE baseline
 constexpr int kSKSEMinBuild = 20100;
 
+HMODULE g_SKSEModuleHandle{nullptr};
+
 struct FileVersion
 {
     static constexpr uint8_t scVersionSize = 4;
@@ -71,6 +73,11 @@ std::string GetSKSEStyleExeVersion()
 }
 } // namespace
 
+bool IsScriptExtenderLoaded()
+{
+    return g_SKSEModuleHandle;
+}
+
 void LoadScriptExender()
 {
     const auto exeVerson{GetSKSEStyleExeVersion()};
@@ -133,9 +140,9 @@ void LoadScriptExender()
     }
 #endif
 
-    if (auto* pSKSELibraryHandle = LoadLibraryW(needle->c_str()))
+    if (g_SKSEModuleHandle = LoadLibraryW(needle->c_str()))
     {
-        if (auto* pStartSKSE = reinterpret_cast<void (*)()>(GetProcAddress(pSKSELibraryHandle, "StartSKSE")))
+        if (auto* pStartSKSE = reinterpret_cast<void (*)()>(GetProcAddress(g_SKSEModuleHandle, "StartSKSE")))
         {
             spdlog::info(
                 "Starting SKSE {}... be aware that messages that start without a colored [timestamp] prefix are "

Code/client/ScriptExtender.h

@@ -1,6 +1,7 @@
 #pragma once
-
 // Utility to import the 3rd-party Script Extender made by Ian Patterson et al.
 // Required for non-Creation Kit mods such as SkyUI
-
 void LoadScriptExender();
+
+// Check if the SE is active
+bool IsScriptExtenderLoaded();

Code/client/Services/Generic/TransportService.cpp

@@ -16,10 +16,13 @@
 #include <Messages/AuthenticationRequest.h>
 #include <Messages/ServerMessageFactory.h>
 
+#include <ScriptExtender.h>
 #include <Services/DiscordService.h>
 
 //#include <imgui_internal.h>
 
+static constexpr wchar_t kMO2DllName[] = L"usvfs_x64.dll";
+
 using TiltedPhoques::Packet;
 
 TransportService::TransportService(World& aWorld, entt::dispatcher& aDispatcher) noexcept
@@ -98,12 +101,14 @@ void TransportService::OnConnected()
 {
     AuthenticationRequest request;
     request.Version = BUILD_COMMIT;
+    request.SKSEActive = IsScriptExtenderLoaded();
+    request.MO2Active = GetModuleHandleW(kMO2DllName);
 
     // null if discord is not active
     // TODO: think about user opt out
     request.DiscordId = m_world.ctx().at<DiscordService>().GetUser().id;
-    auto* pNpc = Cast<TESNPC>(PlayerCharacter::Get()->baseForm);
-    if (pNpc)
+
+    if (auto* pNpc = Cast<TESNPC>(PlayerCharacter::Get()->baseForm))
     {
         request.Username = pNpc->fullName.value.AsAscii();
     }
@@ -148,9 +153,10 @@ void TransportService::HandleUpdate(const UpdateEvent& acEvent) noexcept
 
 void TransportService::HandleAuthenticationResponse(const AuthenticationResponse& acMessage) noexcept
 {
+    using AR = AuthenticationResponse::ResponseType;
     switch (acMessage.Type)
     {
-    case AuthenticationResponse::ResponseType::kAccepted: 
+    case AR::kAccepted: 
     {
         m_connected = true;
         m_dispatcher.trigger(acMessage.UserMods);
@@ -159,10 +165,10 @@ void TransportService::HandleAuthenticationResponse(const AuthenticationResponse
         break;
     }
     // TODO(Anyone): Handle this within the ui
-    case AuthenticationResponse::ResponseType::kWrongVersion:
+    case AR::kWrongVersion:
         spdlog::error("This server expects version {} but you are on version {}", acMessage.Version, BUILD_COMMIT);
         break;
-    case AuthenticationResponse::ResponseType::kMissingMods: {
+    case AR::kModsMismatch: {
         spdlog::error("This server has ModPolicy enabled. You were kicked because you have the following mods installed:");
         for (const auto& m : acMessage.UserMods.ModList)
         {
@@ -171,6 +177,17 @@ void TransportService::HandleAuthenticationResponse(const AuthenticationResponse
         spdlog::error("Please remove them to join");
         break;
     }
+    case AR::kClientModsDisallowed: {
+        TiltedPhoques::String reason = "This server disallows";
+
+        if (acMessage.SKSEActive)
+            reason += " SKSE";
+
+        if (acMessage.MO2Active)
+            reason += " MO2";
+        spdlog::error(reason.c_str());
+        break;
+    }
     default:
         spdlog::error("The server refused connection without reason.");
         break;

Code/encoding/Messages/AuthenticationRequest.cpp

@@ -3,6 +3,8 @@
 void AuthenticationRequest::SerializeRaw(TiltedPhoques::Buffer::Writer& aWriter) const noexcept
 {
     Serialization::WriteVarInt(aWriter, DiscordId);
+    Serialization::WriteBool(aWriter, SKSEActive);
+    Serialization::WriteBool(aWriter, MO2Active);
     Serialization::WriteString(aWriter, Token);
     Serialization::WriteString(aWriter, Version);
     UserMods.Serialize(aWriter);
@@ -14,6 +16,8 @@ void AuthenticationRequest::DeserializeRaw(TiltedPhoques::Buffer::Reader& aReade
     ClientMessage::DeserializeRaw(aReader);
 
     DiscordId = Serialization::ReadVarInt(aReader);
+    SKSEActive = Serialization::ReadBool(aReader);
+    MO2Active = Serialization::ReadBool(aReader);
     Token = Serialization::ReadString(aReader);
     Version = Serialization::ReadString(aReader);
     UserMods.Deserialize(aReader);

Code/encoding/Messages/AuthenticationRequest.h

@@ -1,8 +1,8 @@
 #pragma once
 
 #include "Message.h"
-#include <TiltedCore/Buffer.hpp>
 #include <Structs/Mods.h>
+#include <TiltedCore/Buffer.hpp>
 
 struct AuthenticationRequest final : ClientMessage
 {
@@ -19,15 +19,14 @@ struct AuthenticationRequest final : ClientMessage
 
     bool operator==(const AuthenticationRequest& achRhs) const noexcept
     {
-        return DiscordId == achRhs.DiscordId &&
-            Token == achRhs.Token &&
-            Version == achRhs.Version &&
-            UserMods == achRhs.UserMods && 
-            Username == achRhs.Username &&
-            GetOpcode() == achRhs.GetOpcode();
+        return GetOpcode() == achRhs.GetOpcode() && DiscordId == achRhs.DiscordId && SKSEActive == achRhs.SKSEActive &&
+               MO2Active == achRhs.MO2Active && Token == achRhs.Token && Version == achRhs.Version &&
+               UserMods == achRhs.UserMods && Username == achRhs.Username;
     }
 
     uint64_t DiscordId;
+    bool SKSEActive;
+    bool MO2Active; 
     String Token;
     String Version;
     Mods UserMods;

Code/encoding/Messages/AuthenticationResponse.cpp

@@ -3,6 +3,8 @@
 void AuthenticationResponse::SerializeRaw(TiltedPhoques::Buffer::Writer& aWriter) const noexcept
 {
     Serialization::WriteVarInt(aWriter, static_cast<uint32_t>(Type));
+    Serialization::WriteBool(aWriter, SKSEActive);
+    Serialization::WriteBool(aWriter, MO2Active);
     Serialization::WriteString(aWriter, Version);
     UserMods.Serialize(aWriter);
     Settings.Serialize(aWriter);
@@ -11,6 +13,8 @@ void AuthenticationResponse::SerializeRaw(TiltedPhoques::Buffer::Writer& aWriter
 void AuthenticationResponse::DeserializeRaw(TiltedPhoques::Buffer::Reader& aReader) noexcept
 {
     Type = static_cast<ResponseType>(Serialization::ReadVarInt(aReader) & 0xFFFFFFFF);
+    SKSEActive = Serialization::ReadBool(aReader);
+    MO2Active = Serialization::ReadBool(aReader);
     Version = Serialization::ReadString(aReader);
     UserMods.Deserialize(aReader);
     Settings.Deserialize(aReader);

Code/encoding/Messages/AuthenticationResponse.h

@@ -12,7 +12,8 @@ struct AuthenticationResponse final : ServerMessage
     {
         kAccepted,
         kWrongVersion,
-        kMissingMods,
+        kModsMismatch,
+        kClientModsDisallowed,
     };
 
     AuthenticationResponse() : ServerMessage(Opcode)
@@ -24,13 +25,13 @@ struct AuthenticationResponse final : ServerMessage
 
     bool operator==(const AuthenticationResponse& achRhs) const noexcept
     {
-        return GetOpcode() == achRhs.GetOpcode() && 
-               Type == achRhs.Type && 
-               UserMods == achRhs.UserMods &&
+        return GetOpcode() == achRhs.GetOpcode() && Type == achRhs.Type && UserMods == achRhs.UserMods &&
                Settings == achRhs.Settings;
     }
 
     ResponseType Type;
+    bool SKSEActive{false};
+    bool MO2Active{false}; 
     String Version;
     Mods UserMods{};
     ServerSettings Settings{};

Code/server/GameServer.cpp

@@ -4,7 +4,6 @@
 #include <GameServer.h>
 #include <Packet.hpp>
 
-
 #include <Events/AdminPacketEvent.h>
 #include <Events/CharacterRemoveEvent.h>
 #include <Events/OwnershipTransferEvent.h>
@@ -38,27 +37,39 @@ Console::StringSetting sServerIconURL{"GameServer:sIconUrl", "URL to the image t
 Console::StringSetting sTagList{"GameServer:sTagList", "List of tags, separated by a comma (,)", ""};
 Console::StringSetting sAdminPassword{"GameServer:sAdminPassword", "Admin authentication password", ""};
 Console::StringSetting sToken{"GameServer:sToken", "Admin token", ""};
-Console::Setting bEnableMoPo{"ModPolicy:bEnabled", "Bypass the mod policy restrictions.", true,
-                             Console::SettingsFlags::kHidden | Console::SettingsFlags::kLocked};
 Console::Setting uDifficulty{"Gameplay:uDifficulty", "In game difficulty (0 to 5)", 4u};
+
+// ModPolicy Stuff
+Console::Setting bEnableMoPo{"ModPolicy:bDisableModCheck", "Bypass the checking of mods on the server", true,
+                             Console::SettingsFlags::kHidden | Console::SettingsFlags::kLocked};
+Console::Setting bDisallowSKSE{"ModPolicy:bDisallowSKSE", "Forbids joining of clients that have SKSE running", false,
+                               Console::SettingsFlags::kHidden | Console::SettingsFlags::kLocked};
+Console::Setting bDisallowMO2{"ModPolicy:bDisallowMO2", "Forbids joining of client that use Mod Organizer 2", false,
+                              Console::SettingsFlags::kHidden | Console::SettingsFlags::kLocked};
 // -- Commands --
 Console::Command<bool> TogglePremium("TogglePremium", "Toggle the premium mode",
                                      [](Console::ArgStack& aStack) { bPremiumTickrate = aStack.Pop<bool>(); });
 
 Console::Command<> ShowVersion("version", "Show the version the server was compiled with",
                                [](Console::ArgStack&) { spdlog::get("ConOut")->info("Server " BUILD_COMMIT); });
-Console::Command<> CrashServer("crash", "Crashes the server, don't use!", [](Console::ArgStack&) { int* i = 0; *i = 42; });
-Console::Command<> ShowMoPoStatus("isMoPoActive", "Shows if the ModPolicy is active", [](Console::ArgStack&) {
-    spdlog::get("ConOut")->info("ModPolicy status: {}", bEnableMoPo ? "active" : "not active");
+Console::Command<> CrashServer("crash", "Crashes the server, don't use!", [](Console::ArgStack&) {
+    int* i = 0;
+    *i = 42;
+});
+Console::Command<> ShowMoPoStatus("showMoPOStatus", "Shows the status of ModPolicy", [](Console::ArgStack&) {
+    auto formatStatus = [](bool aToggle) { return aToggle ? "yes" : "no"; };
+
+    spdlog::get("ConOut")->info("Modcheck: {}\nSKSE forbidden: {}\nMO2 forbidden: {}", formatStatus(bEnableMoPo),
+                                formatStatus(bDisallowSKSE), formatStatus(bDisallowMO2));
 });
 
 // -- Constants --
 constexpr char kBypassMoPoWarning[]{
-    "ModPolicy is disabled. This can lead to desync and other oddities. Make sure you know what you are doing. We "
+    "ModCheck is disabled. This can lead to desync and other oddities. Make sure you know what you are doing. We "
     "may not be able to assist you if ModPolicy is disabled."};
 
 constexpr char kMopoRecordsMissing[]{
-    "Failed to start: ModPolicy is enabled, but no mods are installed. Players wont be able "
+    "Failed to start: ModPolicy mod check is enabled, but no mods are installed. Players wont be able "
     "to join! Please install Mods into the /data/ directory."};
 
 } // namespace
@@ -252,7 +263,6 @@ void GameServer::OnUpdate()
 
     auto& dispatcher = m_pWorld->GetDispatcher();
 
-
     dispatcher.trigger(UpdateEvent{cDeltaSeconds});
 
     if (m_requestStop)
@@ -445,6 +455,11 @@ static String PrettyPrintModList(const Vector<Mods::Entry>& acMods)
     return text;
 }
 
+bool GameServer::ValidateAuthParams(ConnectionId_t aConnectionId, const UniquePtr<AuthenticationRequest>& acRequest)
+{
+    return false;
+}
+
 void GameServer::HandleAuthenticationRequest(const ConnectionId_t aConnectionId,
                                              const UniquePtr<AuthenticationRequest>& acRequest)
 {
@@ -455,20 +470,54 @@ void GameServer::HandleAuthenticationRequest(const ConnectionId_t aConnectionId,
 
     AuthenticationResponse serverResponse;
     serverResponse.Version = BUILD_COMMIT;
+
+    using RT = AuthenticationResponse::ResponseType;
+    auto sendKick = [&](const RT type) {
+        serverResponse.Type = type;
+        Send(aConnectionId, serverResponse);
+        // the previous message is a lingering kick, it still gets delivered.
+        Kick(aConnectionId);
+    };
 #if 1
     // to make our testing life a bit easier.
     if (acRequest->Version != BUILD_COMMIT)
     {
         spdlog::info("New player {:x} '{}' tried to connect with client {} - Version mismatch", aConnectionId,
                      remoteAddress, acRequest->Version.c_str());
-
-        serverResponse.Type = AuthenticationResponse::ResponseType::kWrongVersion;
-        Send(aConnectionId, serverResponse);
-        Kick(aConnectionId);
+        sendKick(RT::kWrongVersion);
         return;
     }
 #endif
 
+    bool skseProblem = bDisallowSKSE && acRequest->SKSEActive;
+    bool mo2Problem = bDisallowMO2 && acRequest->MO2Active;
+
+    if (skseProblem || mo2Problem)
+    {
+        TiltedPhoques::String response;
+        if (skseProblem)
+            response += "SKSE ";
+        if (mo2Problem)
+            response += "MO2 ";
+
+        spdlog::info("New player {:x} '{}' tried to connect, but {}disallowed - Kicked.", aConnectionId, remoteAddress,
+                     response.c_str());
+
+        serverResponse.SKSEActive = acRequest->SKSEActive;
+        serverResponse.MO2Active = acRequest->MO2Active;
+        sendKick(RT::kClientModsDisallowed);
+        return;
+    }
+
+    if (bDisallowMO2 && acRequest->MO2Active)
+    {
+        spdlog::info("New player {:x} '{}' tried to connect with ModOrganizer2 - MO2 is disallowed - Kicked.",
+                     aConnectionId, remoteAddress);
+        serverResponse.MO2Active = true;
+        sendKick(RT::kClientModsDisallowed);
+        return;
+    }
+
     // check if the proper server password was supplied.
     if (acRequest->Token == sToken.value())
     {
@@ -520,11 +569,8 @@ void GameServer::HandleAuthenticationRequest(const ConnectionId_t aConnectionId,
                     "ModPolicy: refusing connection {:x} because the following mods are installed on the client: {}",
                     aConnectionId, text.c_str());
 
-                serverResponse.Type = AuthenticationResponse::ResponseType::kMissingMods;
                 serverResponse.UserMods.ModList = std::move(modsToRemove.ModList);
-                Send(aConnectionId, serverResponse);
-                // This is a lingering kick, so sending the response should still succeed.
-                Kick(aConnectionId);
+                sendKick(RT::kModsMismatch);
                 return;
             }
         }

Code/server/GameServer.h

@@ -72,6 +72,7 @@ struct GameServer final : Server
     }
 
 protected:
+    bool ValidateAuthParams(ConnectionId_t aConnectionId, const UniquePtr<AuthenticationRequest>& acRequest);
     void HandleAuthenticationRequest(ConnectionId_t aConnectionId, const UniquePtr<AuthenticationRequest>& acRequest);
 
     // Implement TiltedPhoques::Server

Code/server_runner/DediRunner.cpp

@@ -102,7 +102,7 @@ void DediRunner::ReadStdin(uv_stream_t* apStream, ssize_t aRead, const uv_buf_t*
 
 void DediRunner::AllocateBuffer(uv_handle_t* apHandle, size_t aSuggestedSize, uv_buf_t* apBuffer)
 {
-    *apBuffer = uv_buf_init(static_cast<char*>(TiltedPhoques::Allocator::GetDefault()->Allocate(aSuggestedSize)), aSuggestedSize);
+    *apBuffer = uv_buf_init(static_cast<char*>(TiltedPhoques::Allocator::GetDefault()->Allocate(aSuggestedSize)), static_cast<uint32_t>(aSuggestedSize));
 }
 
 void DediRunner::PrintExecutorArrowHack()