Breath cheat fix: server side

Breath is now handled server side. Changing this behaviour required some modifications to core:

* Ignore TOSERVER_BREATH package, marking it as obsolete
* Clients doesn't send the breath to server anymore
* Use PlayerSAO pointer instead of peer_id in Server::SendPlayerBreath to prevent a useless lookup (little perf gain)
* drop a useless static_cast in emergePlayer

src/client.cpp

@@ -499,7 +499,8 @@ void Client::step(float dtime)
 				m_client_event_queue.push(event);
 			}
 		}
-		else if(event.type == CEE_PLAYER_BREATH) {
+		// Protocol v29 or greater obsoleted this event
+		else if (event.type == CEE_PLAYER_BREATH && m_proto_ver < 29) {
 			u16 breath = event.player_breath.amount;
 			sendBreath(breath);
 		}
@@ -1270,6 +1271,10 @@ void Client::sendBreath(u16 breath)
 {
 	DSTACK(FUNCTION_NAME);
 
+	// Protocol v29 make this obsolete
+	if (m_proto_ver >= 29)
+		return;
+
 	NetworkPacket pkt(TOSERVER_BREATH, sizeof(u16));
 	pkt << breath;
 	Send(&pkt);

src/content_sao.cpp

@@ -26,6 +26,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "serialization.h" // For compressZlib
 #include "tool.h" // For ToolCapabilities
 #include "gamedef.h"
+#include "nodedef.h"
 #include "remoteplayer.h"
 #include "server.h"
 #include "scripting_game.h"
@@ -940,8 +941,35 @@ bool PlayerSAO::isAttached()
 
 void PlayerSAO::step(float dtime, bool send_recommended)
 {
-	if(!m_properties_sent)
+	if (m_drowning_interval.step(dtime, 2.0)) {
-	{
+		// get head position
+		v3s16 p = floatToInt(m_base_position + v3f(0, BS * 1.6, 0), BS);
+		MapNode n = m_env->getMap().getNodeNoEx(p);
+		const ContentFeatures &c = ((Server*) m_env->getGameDef())->ndef()->get(n);
+		// If node generates drown
+		if (c.drowning > 0) {
+			if (m_hp > 0 && m_breath > 0)
+				setBreath(m_breath - 1);
+
+			// No more breath, damage player
+			if (m_breath == 0) {
+				setHP(m_hp - c.drowning);
+				((Server*) m_env->getGameDef())->SendPlayerHPOrDie(this);
+			}
+		}
+	}
+
+	if (m_breathing_interval.step(dtime, 0.5)) {
+		// get head position
+		v3s16 p = floatToInt(m_base_position + v3f(0, BS * 1.6, 0), BS);
+		MapNode n = m_env->getMap().getNodeNoEx(p);
+		const ContentFeatures &c = ((Server*) m_env->getGameDef())->ndef()->get(n);
+		// If player is alive & no drowning, breath
+		if (m_hp > 0 && c.drowning == 0)
+			setBreath(m_breath + 1);
+	}
+
+	if (!m_properties_sent) {
 		m_properties_sent = true;
 		std::string str = getPropertyPacket();
 		// create message and add to list
@@ -1237,12 +1265,15 @@ void PlayerSAO::setHP(s16 hp)
 		m_properties_sent = false;
 }
 
-void PlayerSAO::setBreath(const u16 breath)
+void PlayerSAO::setBreath(const u16 breath, bool send)
 {
 	if (m_player && breath != m_breath)
 		m_player->setDirty(true);
 
-	m_breath = breath;
+	m_breath = MYMIN(breath, PLAYER_MAX_BREATH);
+
+	if (send)
+		((Server *) m_env->getGameDef())->SendPlayerBreath(this);
 }
 
 void PlayerSAO::setArmorGroups(const ItemGroupList &armor_groups)

src/content_sao.h

@@ -20,6 +20,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #ifndef CONTENT_SAO_HEADER
 #define CONTENT_SAO_HEADER
 
+#include <util/numeric.h>
 #include "serverobject.h"
 #include "itemgroup.h"
 #include "object_properties.h"
@@ -232,7 +233,7 @@ public:
 	void setHPRaw(s16 hp) { m_hp = hp; }
 	s16 readDamage();
 	u16 getBreath() const { return m_breath; }
-	void setBreath(const u16 breath);
+	void setBreath(const u16 breath, bool send = true);
 	void setArmorGroups(const ItemGroupList &armor_groups);
 	ItemGroupList getArmorGroups();
 	void setAnimation(v2f frame_range, float frame_speed, float frame_blend, bool frame_loop);
@@ -339,6 +340,10 @@ private:
 	v3s16 m_nocheat_dig_pos;
 	float m_nocheat_dig_time;
 
+	// Timers
+	IntervalLimiter m_breathing_interval;
+	IntervalLimiter m_drowning_interval;
+
 	int m_wield_index;
 	bool m_position_not_sent;
 	ItemGroupList m_armor_groups;

src/environment.cpp

@@ -2511,11 +2511,12 @@ void ClientEnvironment::step(float dtime)
 		}
 	}
 
+	// Protocol v29 make this behaviour obsolete
+	if (((Client*) getGameDef())->getProtoVersion() < 29) {
 		/*
 			Drowning
 		*/
-	if(m_drowning_interval.step(dtime, 2.0))
+		if (m_drowning_interval.step(dtime, 2.0)) {
-	{
 			v3f pf = lplayer->getPosition();
 
 			// head
@@ -2539,8 +2540,7 @@ void ClientEnvironment::step(float dtime)
 				damageLocalPlayer(drowning_damage, true);
 			}
 		}
-	if(m_breathing_interval.step(dtime, 0.5))
+		if (m_breathing_interval.step(dtime, 0.5)) {
-	{
 			v3f pf = lplayer->getPosition();
 
 			// head
@@ -2549,8 +2549,7 @@ void ClientEnvironment::step(float dtime)
 			ContentFeatures c = m_gamedef->ndef()->get(n);
 			if (!lplayer->hp) {
 				lplayer->setBreath(11);
-		}
+			} else if (c.drowning == 0) {
-		else if(c.drowning == 0){
 				u16 breath = lplayer->getBreath();
 				if (breath <= 10) {
 					breath += 1;
@@ -2559,6 +2558,7 @@ void ClientEnvironment::step(float dtime)
 				}
 			}
 		}
+	}
 
 	// Update lighting on local player (used for wield item)
 	u32 day_night_ratio = getDayNightRatio();

src/network/clientopcodes.cpp

@@ -193,7 +193,7 @@ const ServerCommandFactory serverCommandFactoryTable[TOSERVER_NUM_MSG_TYPES] =
 	null_command_factory, // 0x3f
 	{ "TOSERVER_REQUEST_MEDIA",      1, true }, // 0x40
 	{ "TOSERVER_RECEIVED_MEDIA",     1, true }, // 0x41
-	{ "TOSERVER_BREATH",             0, true }, // 0x42
+	null_command_factory, // 0x42 old TOSERVER_BREATH. Ignored by servers
 	{ "TOSERVER_CLIENT_READY",       0, true }, // 0x43
 	null_command_factory, // 0x44
 	null_command_factory, // 0x45

src/network/networkprotocol.h

@@ -138,9 +138,11 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 		Add nodedef v3 - connected nodeboxes
 	PROTOCOL_VERSION 28:
 		CPT2_MESHOPTIONS
+	PROTOCOL_VERSION 29:
+		Server doesn't accept TOSERVER_BREATH anymore
 */
 
-#define LATEST_PROTOCOL_VERSION 28
+#define LATEST_PROTOCOL_VERSION 29
 
 // Server's supported network protocol range
 #define SERVER_PROTOCOL_VERSION_MIN 13
@@ -833,7 +835,7 @@ enum ToServerCommand
 		<no payload data>
 	*/
 
-	TOSERVER_BREATH = 0x42,
+	TOSERVER_BREATH = 0x42, // Obsolete
 	/*
 		u16 breath
 	*/

src/network/serveropcodes.cpp

@@ -90,7 +90,7 @@ const ToServerCommandHandler toServerCommandTable[TOSERVER_NUM_MSG_TYPES] =
 	null_command_handler, // 0x3f
 	{ "TOSERVER_REQUEST_MEDIA",            TOSERVER_STATE_STARTUP, &Server::handleCommand_RequestMedia }, // 0x40
 	{ "TOSERVER_RECEIVED_MEDIA",           TOSERVER_STATE_STARTUP, &Server::handleCommand_ReceivedMedia }, // 0x41
-	{ "TOSERVER_BREATH",                   TOSERVER_STATE_INGAME, &Server::handleCommand_Breath }, // 0x42
+	{ "TOSERVER_BREATH",                   TOSERVER_STATE_INGAME, &Server::handleCommand_Deprecated }, // 0x42 Old breath model which is now deprecated for anticheating
 	{ "TOSERVER_CLIENT_READY",             TOSERVER_STATE_STARTUP, &Server::handleCommand_ClientReady }, // 0x43
 	null_command_handler, // 0x44
 	null_command_handler, // 0x45

src/network/serverpackethandler.cpp

@@ -1136,46 +1136,6 @@ void Server::handleCommand_Damage(NetworkPacket* pkt)
 	}
 }
 
-void Server::handleCommand_Breath(NetworkPacket* pkt)
-{
-	u16 breath;
-
-	*pkt >> breath;
-
-	RemotePlayer *player = m_env->getPlayer(pkt->getPeerId());
-
-	if (player == NULL) {
-		errorstream << "Server::ProcessData(): Canceling: "
-				"No player for peer_id=" << pkt->getPeerId()
-				<< " disconnecting peer!" << std::endl;
-		m_con.DisconnectPeer(pkt->getPeerId());
-		return;
-	}
-
-
-	PlayerSAO *playersao = player->getPlayerSAO();
-	if (playersao == NULL) {
-		errorstream << "Server::ProcessData(): Canceling: "
-				"No player object for peer_id=" << pkt->getPeerId()
-				<< " disconnecting peer!" << std::endl;
-		m_con.DisconnectPeer(pkt->getPeerId());
-		return;
-	}
-
-	/*
-	 * If player is dead, we don't need to update the breath
-	 * He is dead !
-	 */
-	if (playersao->isDead()) {
-		verbosestream << "TOSERVER_BREATH: " << player->getName()
-				<< " is dead. Ignoring packet";
-		return;
-	}
-
-	playersao->setBreath(breath);
-	SendPlayerBreath(pkt->getPeerId());
-}
-
 void Server::handleCommand_Password(NetworkPacket* pkt)
 {
 	if (pkt->getSize() != PASSWORD_SIZE * 2)

src/remoteplayer.cpp

@@ -148,7 +148,7 @@ void RemotePlayer::deSerialize(std::istream &is, const std::string &playername,
 		} catch (SettingNotFoundException &e) {}
 
 		try {
-			sao->setBreath(args.getS32("breath"));
+			sao->setBreath(args.getS32("breath"), false);
 		} catch (SettingNotFoundException &e) {}
 	}
 

src/script/lua_api/l_object.cpp

@@ -1152,13 +1152,8 @@ int ObjectRef::l_set_breath(lua_State *L)
 	PlayerSAO* co = getplayersao(ref);
 	if (co == NULL) return 0;
 	u16 breath = luaL_checknumber(L, 2);
-	// Do it
 	co->setBreath(breath);
 
-	// If the object is a player sent the breath to client
-	if (co->getType() == ACTIVEOBJECT_TYPE_PLAYER)
-			getServer(L)->SendPlayerBreath(((PlayerSAO*)co)->getPeerID());
-
 	return 0;
 }
 

src/server.cpp

@@ -1076,8 +1076,7 @@ PlayerSAO* Server::StageTwoClientInit(u16 peer_id)
 	}
 	m_clients.unlock();
 
-	RemotePlayer *player =
+	RemotePlayer *player = m_env->getPlayer(playername.c_str());
-		static_cast<RemotePlayer*>(m_env->getPlayer(playername.c_str()));
 
 	// If failed, cancel
 	if ((playersao == NULL) || (player == NULL)) {
@@ -1113,7 +1112,7 @@ PlayerSAO* Server::StageTwoClientInit(u16 peer_id)
 	SendPlayerHPOrDie(playersao);
 
 	// Send Breath
-	SendPlayerBreath(peer_id);
+	SendPlayerBreath(playersao);
 
 	// Show death screen if necessary
 	if (playersao->isDead())
@@ -1857,14 +1856,13 @@ void Server::SendPlayerHP(u16 peer_id)
 	playersao->m_messages_out.push(aom);
 }
 
-void Server::SendPlayerBreath(u16 peer_id)
+void Server::SendPlayerBreath(PlayerSAO *sao)
 {
 	DSTACK(FUNCTION_NAME);
-	PlayerSAO *playersao = getPlayerSAO(peer_id);
+	assert(sao);
-	assert(playersao);
 
-	m_script->player_event(playersao, "breath_changed");
+	m_script->player_event(sao, "breath_changed");
-	SendBreath(peer_id, playersao->getBreath());
+	SendBreath(sao->getPeerID(), sao->getBreath());
 }
 
 void Server::SendMovePlayer(u16 peer_id)
@@ -2565,7 +2563,6 @@ void Server::RespawnPlayer(u16 peer_id)
 	}
 
 	SendPlayerHP(peer_id);
-	SendPlayerBreath(peer_id);
 }
 
 

src/server.h

@@ -180,7 +180,6 @@ public:
 	void handleCommand_InventoryAction(NetworkPacket* pkt);
 	void handleCommand_ChatMessage(NetworkPacket* pkt);
 	void handleCommand_Damage(NetworkPacket* pkt);
-	void handleCommand_Breath(NetworkPacket* pkt);
 	void handleCommand_Password(NetworkPacket* pkt);
 	void handleCommand_PlayerItem(NetworkPacket* pkt);
 	void handleCommand_Respawn(NetworkPacket* pkt);
@@ -358,7 +357,7 @@ public:
 	void printToConsoleOnly(const std::string &text);
 
 	void SendPlayerHPOrDie(PlayerSAO *player);
-	void SendPlayerBreath(u16 peer_id);
+	void SendPlayerBreath(PlayerSAO *sao);
 	void SendInventory(PlayerSAO* playerSAO);
 	void SendMovePlayer(u16 peer_id);
 

src/unittest/test_player.cpp

@@ -49,7 +49,7 @@ void TestPlayer::testSave(IGameDef *gamedef)
 	PlayerSAO sao(NULL, 1, false);
 	sao.initialize(&rplayer, std::set<std::string>());
 	rplayer.setPlayerSAO(&sao);
-	sao.setBreath(10);
+	sao.setBreath(10, false);
 	sao.setHPRaw(8);
 	sao.setYaw(0.1f);
 	sao.setPitch(0.6f);
@@ -64,7 +64,7 @@ void TestPlayer::testLoad(IGameDef *gamedef)
 	PlayerSAO sao(NULL, 1, false);
 	sao.initialize(&rplayer, std::set<std::string>());
 	rplayer.setPlayerSAO(&sao);
-	sao.setBreath(10);
+	sao.setBreath(10, false);
 	sao.setHPRaw(8);
 	sao.setYaw(0.1f);
 	sao.setPitch(0.6f);