From 32da740f147f4fa03b8b5676db81cab3414a20d7 Mon Sep 17 00:00:00 2001
From: leper <leper@wildfiregames.com>
Date: Wed, 11 Nov 2015 02:05:23 +0000
Subject: [PATCH] Allow kicking/banning players from gamesetup and session.
 Patch by elexis. Fixes #3241.

This was SVN commit r17217.
---
 .../data/mods/public/gui/common/network.js    | 77 +++++++++++++++++--
 .../mods/public/gui/gamesetup/gamesetup.js    | 22 +++++-
 .../data/mods/public/gui/session/messages.js  | 21 ++++-
 .../data/mods/public/gui/session/session.xml  |  1 +
 source/gui/scripting/ScriptFunctions.cpp      |  9 +++
 source/network/NetClient.cpp                  | 20 +++++
 source/network/NetClient.h                    |  1 +
 source/network/NetHost.h                      |  4 +-
 source/network/NetMessage.cpp                 |  4 +
 source/network/NetMessages.h                  |  8 +-
 source/network/NetServer.cpp                  | 59 +++++++++++++-
 source/network/NetServer.h                    | 17 +++-
 source/network/NetSession.cpp                 | 11 ++-
 source/network/NetSession.h                   |  4 +-
 14 files changed, 245 insertions(+), 13 deletions(-)

diff --git a/binaries/data/mods/public/gui/common/network.js b/binaries/data/mods/public/gui/common/network.js
index 1de4c0fa22..68d92e8da7 100644
--- a/binaries/data/mods/public/gui/common/network.js
+++ b/binaries/data/mods/public/gui/common/network.js
@@ -1,3 +1,9 @@
+/**
+ * Get a human readable version of the given disconnect reason.
+ *
+ * @param reason {number}
+ * @returns {string}
+ */
 function getDisconnectReason(id)
 {
 	// Must be kept in sync with source/network/NetHost.h
@@ -8,15 +14,76 @@ function getDisconnectReason(id)
 	case 2: return translate("Incorrect network protocol version");
 	case 3: return translate("Game is loading, please try later");
 	case 4: return translate("Game has already started, no observers allowed");
+	case 5: return translate("You have been kicked");
+	case 6: return translate("You have been banned");
 	default: return sprintf(translate("\\[Invalid value %(id)s]"), { "id": id });
 	}
 }
 
+/**
+ * Show the disconnect reason in a message box.
+ *
+ * @param {number} reason
+ */
 function reportDisconnect(reason)
 {
-	var reasontext = getDisconnectReason(reason);
-
-	messageBox(400, 200,
-		translate("Lost connection to the server.") + "\n\n" + sprintf(translate("Reason: %(reason)s."), { reason: reasontext }),
-		translate("Disconnected"), 2);
+	// Translation: States the reason why the client disconnected from the server.
+	var reasonText = sprintf(translate("Reason: %(reason)s."), { "reason": getDisconnectReason(reason) })
+	messageBox(400, 200, translate("Lost connection to the server.") + "\n\n" + reasonText, translate("Disconnected"), 2);
+}
+
+/**
+ * Get usernames sorted by player slot, observers last.
+ * Requires g_PlayerAssignments.
+ *
+ * @returns {string[]}
+ */
+function getUsernameList()
+{
+	return Object.keys(g_PlayerAssignments).sort((guidA, guidB) => {
+
+		var playerIdA = g_PlayerAssignments[guidA].player;
+		var playerIdB = g_PlayerAssignments[guidB].player;
+
+		// Sort observers last
+		if (playerIdA == -1) return +1;
+		if (playerIdB == -1) return -1;
+
+		// Sort players
+		return playerIdA - playerIdB;
+
+	}).map(guid => g_PlayerAssignments[guid].name);
+}
+
+/**
+ * Execute a command locally. Requires addChatMessage.
+ *
+ * @param {string} input
+ * @returns {Boolean} whether a command was executed
+ */
+function executeNetworkCommand(input)
+{
+	if (input.indexOf("/") != 0)
+		return false;
+
+	var command = input.split(" ", 1)[0];
+	var argument = input.substr(command.length + 1);
+
+	switch (command)
+	{
+	case "/list":
+		addChatMessage({ "type": "clientlist", "guid": "local" });
+		return true;
+
+	case "/kick":
+		if (!Engine.KickPlayer(argument, false))
+			addChatMessage({ "type": "system", "text": sprintf(translate("Could not kick %(name)s."), { "name": argument }) });
+		return true;
+
+	case "/ban":
+		if (!Engine.KickPlayer(argument, true))
+			addChatMessage({ "type": "system", "text": sprintf(translate("Could not ban %(name)s."), { "name": argument }) });
+		return true;
+	}
+	return false;
 }
diff --git a/binaries/data/mods/public/gui/gamesetup/gamesetup.js b/binaries/data/mods/public/gui/gamesetup/gamesetup.js
index a8b3517c5a..1cb8e5ceb6 100644
--- a/binaries/data/mods/public/gui/gamesetup/gamesetup.js
+++ b/binaries/data/mods/public/gui/gamesetup/gamesetup.js
@@ -508,6 +508,14 @@ function handleNetMessage(message)
 		addChatMessage({ "type": "message", "guid": message.guid, "text": message.text });
 		break;
 
+	case "kicked":
+		addChatMessage({ "type": "system", "text": sprintf(translate("%(username)s has been kicked"), { "username": message.username })});
+		break;
+
+	case "banned":
+		addChatMessage({ "type": "system", "text": sprintf(translate("%(username)s has been banned"), { "username": message.username })});
+		break;
+
 	// Singular client to host message
 	case "ready":
 		g_ReadyChanged -= 1;
@@ -1776,8 +1784,12 @@ function submitChatInput()
 	if (!text.length)
 		return;
 
-	Engine.SendNetworkChat(text);
 	input.caption = "";
+
+	if (executeNetworkCommand(text))
+		return;
+
+	Engine.SendNetworkChat(text);
 }
 
 function addChatMessage(msg)
@@ -1812,6 +1824,14 @@ function addChatMessage(msg)
 		formatted = '[font="sans-bold-13"] ' + sprintf(translate("== %(message)s"), { "message": sprintf(translate("%(username)s has left"), { "username": formattedUsername }) }) + '[/font]';
 		break;
 
+	case "clientlist":
+		formatted = sprintf(translate("Users: %(users)s"), { "users": getUsernameList().join(translate(", ")) });
+		break;
+
+	case "system":
+		formatted = '[font="sans-bold-13"] ' + sprintf(translate("== %(message)s"), { "message": msg.text }) + '[/font]';
+		break;
+
 	case "message":
 		var formattedUsername = '[color="'+ color +'"]' + username + '[/color]';
 		var formattedUsernamePrefix = '[font="sans-bold-13"]' + sprintf(translate("<%(username)s>"), { "username": formattedUsername }) + '[/font]';
diff --git a/binaries/data/mods/public/gui/session/messages.js b/binaries/data/mods/public/gui/session/messages.js
index be41e25a37..648a3cb8a9 100644
--- a/binaries/data/mods/public/gui/session/messages.js
+++ b/binaries/data/mods/public/gui/session/messages.js
@@ -269,7 +269,9 @@ function handleNetMessage(message)
 			break;
 		case "disconnected":
 			g_Disconnected = true;
-			obj.caption = translate("Connection to the server has been lost.") + "\n\n" + translate("The game has ended.");
+			// Translation: States the reason why the client disconnected from the server.
+			let reason = sprintf(translate("Reason: %(reason)s."), { "reason": getDisconnectReason(message.reason) });
+			obj.caption = translate("Connection to the server has been lost.") + "\n" + reason + "\n" + translate("The game has ended.");
 			obj.hidden = false;
 			break;
 		default:
@@ -325,6 +327,14 @@ function handleNetMessage(message)
 		addChatMessage({ "type": "rejoined", "guid": message.guid });
 		break;
 
+	case "kicked":
+		addChatMessage({ "type": "system", "text": sprintf(translate("%(username)s has been kicked"), { "username": message.username })});
+		break;
+
+	case "banned":
+		addChatMessage({ "type": "system", "text": sprintf(translate("%(username)s has been banned"), { "username": message.username })});
+		break;
+
 	// To prevent errors, ignore these message types that occur during autostart
 	case "gamesetup":
 	case "start":
@@ -359,6 +369,9 @@ function submitChatInput()
 	if (!text.length)
 		return;
 
+	if (executeNetworkCommand(text))
+		return;
+
 	if (executeCheat(text))
 		return;
 
@@ -420,6 +433,12 @@ function addChatMessage(msg)
 	case "rejoined":
 		formatted = sprintf(translate("%(player)s has rejoined the game."), { "player": "[color=\"" + playerColor + "\"]" + username + "[/color]" });
 		break;
+	case "clientlist":
+		formatted = sprintf(translate("Users: %(users)s"), { "users": getUsernameList().join(translate(", ")) });
+		break;
+	case "system":
+		formatted = msg.text;
+		break;
 	case "defeat":
 		// In singleplayer, the local player is "You". "You has" is incorrect.
 		if (!g_IsNetworked && msg.player == Engine.GetPlayerID())
diff --git a/binaries/data/mods/public/gui/session/session.xml b/binaries/data/mods/public/gui/session/session.xml
index 9e2bc57e83..67628a4d2b 100644
--- a/binaries/data/mods/public/gui/session/session.xml
+++ b/binaries/data/mods/public/gui/session/session.xml
@@ -8,6 +8,7 @@
 <script file="gui/common/functions_utility.js"/>
 <script file="gui/common/l10n.js"/>
 <script file="gui/common/music.js"/>
+<script file="gui/common/network.js"/>
 <script file="gui/common/settings.js"/>
 <script file="gui/common/timer.js"/>
 <script file="gui/common/tooltips.js"/>
diff --git a/source/gui/scripting/ScriptFunctions.cpp b/source/gui/scripting/ScriptFunctions.cpp
index 1d7e447723..56eae41376 100644
--- a/source/gui/scripting/ScriptFunctions.cpp
+++ b/source/gui/scripting/ScriptFunctions.cpp
@@ -353,6 +353,14 @@ void DisconnectNetworkGame(ScriptInterface::CxPrivate* UNUSED(pCxPrivate))
 	SAFE_DELETE(g_Game);
 }
 
+bool KickPlayer(ScriptInterface::CxPrivate* UNUSED(pCxPrivate), CStrW playerName, bool ban)
+{
+	if (!g_NetServer)
+		return false;
+
+	return g_NetServer->KickPlayer(playerName, ban);
+}
+
 JS::Value PollNetworkClient(ScriptInterface::CxPrivate* pCxPrivate)
 {
 	if (!g_NetClient)
@@ -963,6 +971,7 @@ void GuiScriptingInit(ScriptInterface& scriptInterface)
 	scriptInterface.RegisterFunction<void, std::wstring, &StartNetworkHost>("StartNetworkHost");
 	scriptInterface.RegisterFunction<void, std::wstring, std::string, &StartNetworkJoin>("StartNetworkJoin");
 	scriptInterface.RegisterFunction<void, &DisconnectNetworkGame>("DisconnectNetworkGame");
+	scriptInterface.RegisterFunction<bool, CStrW, bool, &KickPlayer>("KickPlayer");
 	scriptInterface.RegisterFunction<JS::Value, &PollNetworkClient>("PollNetworkClient");
 	scriptInterface.RegisterFunction<void, JS::HandleValue, &SetNetworkGameAttributes>("SetNetworkGameAttributes");
 	scriptInterface.RegisterFunction<void, int, std::string, &AssignNetworkPlayer>("AssignNetworkPlayer");
diff --git a/source/network/NetClient.cpp b/source/network/NetClient.cpp
index c5f9c7d7c7..b70e5758dd 100644
--- a/source/network/NetClient.cpp
+++ b/source/network/NetClient.cpp
@@ -93,6 +93,7 @@ CNetClient::CNetClient(CGame* game) :
 	AddTransition(NCS_PREGAME, (uint)NMT_READY, NCS_PREGAME, (void*)&OnReady, context);
 	AddTransition(NCS_PREGAME, (uint)NMT_GAME_SETUP, NCS_PREGAME, (void*)&OnGameSetup, context);
 	AddTransition(NCS_PREGAME, (uint)NMT_PLAYER_ASSIGNMENT, NCS_PREGAME, (void*)&OnPlayerAssignment, context);
+	AddTransition(NCS_PREGAME, (uint)NMT_KICKED, NCS_PREGAME, (void*)&OnKicked, context);
 	AddTransition(NCS_PREGAME, (uint)NMT_GAME_START, NCS_LOADING, (void*)&OnGameStart, context);
 	AddTransition(NCS_PREGAME, (uint)NMT_JOIN_SYNC_START, NCS_JOIN_SYNCING, (void*)&OnJoinSyncStart, context);
 
@@ -110,6 +111,7 @@ CNetClient::CNetClient(CGame* game) :
 	AddTransition(NCS_LOADING, (uint)NMT_LOADED_GAME, NCS_INGAME, (void*)&OnLoadedGame, context);
 
 	AddTransition(NCS_INGAME, (uint)NMT_REJOINED, NCS_INGAME, (void*)&OnRejoined, context);
+	AddTransition(NCS_INGAME, (uint)NMT_KICKED, NCS_INGAME, (void*)&OnKicked, context);
 	AddTransition(NCS_INGAME, (uint)NMT_CHAT, NCS_INGAME, (void*)&OnChat, context);
 	AddTransition(NCS_INGAME, (uint)NMT_GAME_SETUP, NCS_INGAME, (void*)&OnGameSetup, context);
 	AddTransition(NCS_INGAME, (uint)NMT_PLAYER_ASSIGNMENT, NCS_INGAME, (void*)&OnPlayerAssignment, context);
@@ -607,6 +609,24 @@ bool CNetClient::OnRejoined(void *context, CFsmEvent* event)
 	return true;
 }
 
+bool CNetClient::OnKicked(void *context, CFsmEvent* event)
+{
+	ENSURE(event->GetType() == (uint)NMT_KICKED);
+
+	CNetClient* client = (CNetClient*)context;
+	JSContext* cx = client->GetScriptInterface().GetContext();
+
+	CKickedMessage* message = (CKickedMessage*)event->GetParamRef();
+	JS::RootedValue msg(cx);
+
+	client->GetScriptInterface().Eval("({})", &msg);
+	client->GetScriptInterface().SetProperty(msg, "username", message->m_Name);
+	client->GetScriptInterface().SetProperty(msg, "type", message->m_Ban ? std::string("banned") : std::string("kicked"));
+	client->PushGuiMessage(msg);
+
+	return true;
+}
+
 bool CNetClient::OnLoadedGame(void* context, CFsmEvent* event)
 {
 	ENSURE(event->GetType() == (uint)NMT_LOADED_GAME);
diff --git a/source/network/NetClient.h b/source/network/NetClient.h
index 4269f8cf5d..cb1fff221c 100644
--- a/source/network/NetClient.h
+++ b/source/network/NetClient.h
@@ -201,6 +201,7 @@ private:
 	static bool OnJoinSyncStart(void* context, CFsmEvent* event);
 	static bool OnJoinSyncEndCommandBatch(void* context, CFsmEvent* event);
 	static bool OnRejoined(void* context, CFsmEvent* event);
+	static bool OnKicked(void* context, CFsmEvent* event);
 	static bool OnLoadedGame(void* context, CFsmEvent* event);
 
 	/**
diff --git a/source/network/NetHost.h b/source/network/NetHost.h
index 0552617708..e0dea1f247 100644
--- a/source/network/NetHost.h
+++ b/source/network/NetHost.h
@@ -63,7 +63,9 @@ enum NetDisconnectReason
 	NDR_UNEXPECTED_SHUTDOWN,
 	NDR_INCORRECT_PROTOCOL_VERSION,
 	NDR_SERVER_LOADING,
-	NDR_SERVER_ALREADY_IN_GAME
+	NDR_SERVER_ALREADY_IN_GAME,
+	NDR_KICKED,
+	NDR_BANNED
 };
 
 class CNetHost
diff --git a/source/network/NetMessage.cpp b/source/network/NetMessage.cpp
index 1dd31d5105..bf35f2639d 100644
--- a/source/network/NetMessage.cpp
+++ b/source/network/NetMessage.cpp
@@ -135,6 +135,10 @@ CNetMessage* CNetMessageFactory::CreateMessage(const void* pData,
 		pNewMessage = new CRejoinedMessage;
 		break;
 
+	case NMT_KICKED:
+		pNewMessage = new CKickedMessage;
+		break;
+
 	case NMT_LOADED_GAME:
 		pNewMessage = new CLoadedGameMessage;
 		break;
diff --git a/source/network/NetMessages.h b/source/network/NetMessages.h
index ca78bfaa59..81e58ad78a 100644
--- a/source/network/NetMessages.h
+++ b/source/network/NetMessages.h
@@ -28,7 +28,7 @@
 
 #define PS_PROTOCOL_MAGIC				0x5073013f		// 'P', 's', 0x01, '?'
 #define PS_PROTOCOL_MAGIC_RESPONSE		0x50630121		// 'P', 'c', 0x01, '!'
-#define PS_PROTOCOL_VERSION				0x01010007		// Arbitrary protocol
+#define PS_PROTOCOL_VERSION				0x01010008		// Arbitrary protocol
 #define PS_DEFAULT_PORT					0x5073			// 'P', 's'
 
 // Defines the list of message types. The order of the list must not change.
@@ -58,6 +58,7 @@ enum NetMessageType
 	NMT_JOIN_SYNC_START,
 
 	NMT_REJOINED,
+	NMT_KICKED,
 
 	NMT_LOADED_GAME,
 	NMT_GAME_START,
@@ -161,6 +162,11 @@ START_NMT_CLASS_(Rejoined, NMT_REJOINED)
 	NMT_FIELD(CStr8, m_GUID)
 END_NMT_CLASS()
 
+START_NMT_CLASS_(Kicked, NMT_KICKED)
+	NMT_FIELD(CStrW, m_Name)
+	NMT_FIELD_INT(m_Ban, u8, 1)
+END_NMT_CLASS()
+
 START_NMT_CLASS_(LoadedGame, NMT_LOADED_GAME)
 	NMT_FIELD_INT(m_CurrentTurn, u32, 4)
 END_NMT_CLASS()
diff --git a/source/network/NetServer.cpp b/source/network/NetServer.cpp
index f4ff719a9a..2e94b1b024 100644
--- a/source/network/NetServer.cpp
+++ b/source/network/NetServer.cpp
@@ -121,7 +121,7 @@ CNetServerWorker::CNetServerWorker(int autostartPlayers) :
 	m_AutostartPlayers(autostartPlayers),
 	m_Shutdown(false),
 	m_ScriptInterface(NULL),
-	m_NextHostID(1), m_Host(NULL), m_Stats(NULL)
+	m_NextHostID(1), m_Host(NULL), m_HostGUID(), m_Stats(NULL)
 {
 	m_State = SERVER_STATE_UNCONNECTED;
 
@@ -610,6 +610,12 @@ void CNetServerWorker::SetupSession(CNetServerSession* session)
 
 bool CNetServerWorker::HandleConnect(CNetServerSession* session)
 {
+	if (std::find(m_BannedIPs.begin(), m_BannedIPs.end(), session->GetIPAddress()) != m_BannedIPs.end())
+	{
+		session->Disconnect(NDR_BANNED);
+		return false;
+	}
+
 	CSrvHandshakeMessage handshake;
 	handshake.m_Magic = PS_PROTOCOL_MAGIC;
 	handshake.m_ProtocolVersion = PS_PROTOCOL_VERSION;
@@ -621,6 +627,10 @@ void CNetServerWorker::OnUserJoin(CNetServerSession* session)
 {
 	AddPlayer(session->GetGUID(), session->GetUserName());
 
+	// Host is the first to join
+	if (m_HostGUID.empty())
+		m_HostGUID = session->GetGUID();
+
 	CGameSetupMessage gameSetupMessage(GetScriptInterface());
 	gameSetupMessage.m_Data = m_GameAttributes.get();
 	session->SendMessage(&gameSetupMessage);
@@ -713,6 +723,40 @@ void CNetServerWorker::ClearAllPlayerReady()
 	SendPlayerAssignments();
 }
 
+bool CNetServerWorker::KickPlayer(const CStrW& playerName, const bool ban)
+{
+	// Find the user with that name
+	std::vector<CNetServerSession*>::iterator it = std::find_if(m_Sessions.begin(), m_Sessions.end(),
+		[&](CNetServerSession* session) { return session->GetUserName() == playerName; });
+
+	// and return if no one or the host has that name
+	if (it == m_Sessions.end() || (*it)->GetGUID() == m_HostGUID)
+		return false;
+
+	if (ban)
+	{
+		// Remember name
+		if (std::find(m_BannedPlayers.begin(), m_BannedPlayers.end(), playerName) == m_BannedPlayers.end())
+			m_BannedPlayers.push_back(playerName);
+
+		// Remember IP address
+		CStr ipAddress = (*it)->GetIPAddress();
+		if (!ipAddress.empty() && std::find(m_BannedIPs.begin(), m_BannedIPs.end(), ipAddress) == m_BannedIPs.end())
+			m_BannedIPs.push_back(ipAddress);
+	}
+
+	// Disconnect that user
+	(*it)->Disconnect(ban ? NDR_BANNED : NDR_KICKED);
+
+	// Send message notifying other clients
+	CKickedMessage kickedMessage;
+	kickedMessage.m_Name = playerName;
+	kickedMessage.m_Ban = ban;
+	Broadcast(&kickedMessage);
+
+	return true;
+}
+
 void CNetServerWorker::AssignPlayer(int playerID, const CStr& guid)
 {
 	// Remove anyone who's already assigned to this player
@@ -804,6 +848,13 @@ bool CNetServerWorker::OnAuthenticate(void* context, CFsmEvent* event)
 	CAuthenticateMessage* message = (CAuthenticateMessage*)event->GetParamRef();
 	CStrW username = server.DeduplicatePlayerName(SanitisePlayerName(message->m_Name));
 
+	// Disconnect banned usernames
+	if (std::find(server.m_BannedPlayers.begin(), server.m_BannedPlayers.end(), username) != server.m_BannedPlayers.end())
+	{
+		session->Disconnect(NDR_BANNED);
+		return true;
+	}
+
 	// Optionally allow observers to join after the game has started
 	bool observerLateJoin = false;
 	ScriptInterface& scriptInterface = server.GetScriptInterface();
@@ -1168,6 +1219,12 @@ bool CNetServer::SetupConnection()
 	return m_Worker->SetupConnection();
 }
 
+bool CNetServer::KickPlayer(const CStrW& playerName, const bool ban)
+{
+	CScopeLock lock(m_Worker->m_WorkerMutex);
+	return m_Worker->KickPlayer(playerName, ban);
+}
+
 void CNetServer::AssignPlayer(int playerID, const CStr& guid)
 {
 	CScopeLock lock(m_Worker->m_WorkerMutex);
diff --git a/source/network/NetServer.h b/source/network/NetServer.h
index a82af8242c..854bc0617c 100644
--- a/source/network/NetServer.h
+++ b/source/network/NetServer.h
@@ -134,7 +134,12 @@ public:
 	 * The changes will be asynchronously propagated to all clients.
 	 */
 	void ClearAllPlayerReady();
-	
+
+	/**
+	 * Disconnects a player from gamesetup or session.
+	 */
+	bool KickPlayer(const CStrW& playerName, const bool ban);
+
 	/**
 	 * Call from the GUI to asynchronously notify all clients that they should start loading the game.
 	 */
@@ -182,6 +187,11 @@ public:
 	 */
 	bool SendMessage(ENetPeer* peer, const CNetMessage* message);
 
+	/**
+	 * Disconnects a player from gamesetup or session.
+	 */
+	bool KickPlayer(const CStrW& playerName, const bool ban);
+
 	/**
 	 * Send a message to all clients who have completed the full connection process
 	 * (i.e. are in the pre-game or in-game states).
@@ -299,10 +309,15 @@ private:
 	CStrW m_ServerName;
 	CStrW m_WelcomeMessage;
 
+	std::vector<CStr> m_BannedIPs;
+	std::vector<CStrW> m_BannedPlayers;
+
 	u32 m_NextHostID;
 
 	CNetServerTurnManager* m_ServerTurnManager;
 
+	CStr m_HostGUID;
+
 	/**
 	 * A copy of all simulation commands received so far, indexed by
 	 * turn number, to simplify support for rejoining etc.
diff --git a/source/network/NetSession.cpp b/source/network/NetSession.cpp
index 82fa031569..6618f3bac8 100644
--- a/source/network/NetSession.cpp
+++ b/source/network/NetSession.cpp
@@ -1,4 +1,4 @@
-/* Copyright (C) 2011 Wildfire Games.
+/* Copyright (C) 2015 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -175,6 +175,15 @@ CNetServerSession::CNetServerSession(CNetServerWorker& server, ENetPeer* peer) :
 {
 }
 
+CStr CNetServerSession::GetIPAddress() const
+{
+	char ipAddress[256] = "";
+	if (enet_address_get_host_ip(&m_Peer->address, ipAddress, ARRAY_SIZE(ipAddress)) < 0)
+		LOGMESSAGE("Could not get IP address of a client!");
+
+	return ipAddress;
+}
+
 void CNetServerSession::Disconnect(u32 reason)
 {
 	Update((uint)NMT_CONNECTION_LOST, NULL);
diff --git a/source/network/NetSession.h b/source/network/NetSession.h
index dc35f13b9a..40362dfb97 100644
--- a/source/network/NetSession.h
+++ b/source/network/NetSession.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2011 Wildfire Games.
+/* Copyright (C) 2015 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -122,6 +122,8 @@ public:
 	u32 GetHostID() const { return m_HostID; }
 	void SetHostID(u32 id) { m_HostID = id; }
 
+	CStr GetIPAddress() const;
+
 	/**
 	 * Sends a disconnection notification to the client,
 	 * and sends a NMT_CONNECTION_LOST message to the session FSM.