minetest/src/network/clientpackethandler.cpp

/*
Minetest
Copyright (C) 2015 nerzhul, Loic Blot <loic.blot@unix-experience.fr>

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/

#include "client/client.h"

#include "util/base64.h"
#include "chatmessage.h"
#include "client/clientmedia.h"
#include "log.h"
#include "map.h"
#include "mapsector.h"
#include "client/minimap.h"
#include "modchannels.h"
#include "nodedef.h"
#include "serialization.h"
#include "server.h"
#include "util/strfnd.h"
#include "client/clientevent.h"
#include "client/sound.h"
#include "network/clientopcodes.h"
#include "network/connection.h"
#include "script/scripting_client.h"
#include "util/serialize.h"
#include "util/srp.h"
#include "tileanimation.h"
#include "gettext.h"
#include "skyparams.h"

void Client::handleCommand_Deprecated(NetworkPacket* pkt)
{
	infostream << "Got deprecated command "
			<< toClientCommandTable[pkt->getCommand()].name << " from peer "
			<< pkt->getPeerId() << "!" << std::endl;
}

void Client::handleCommand_Hello(NetworkPacket* pkt)
{
	if (pkt->getSize() < 1)
		return;

	u8 serialization_ver;
	u16 proto_ver;
	u16 compression_mode;
	u32 auth_mechs;
	std::string username_legacy; // for case insensitivity
	*pkt >> serialization_ver >> compression_mode >> proto_ver
		>> auth_mechs >> username_legacy;

	// Chose an auth method we support
	AuthMechanism chosen_auth_mechanism = choseAuthMech(auth_mechs);

	infostream << "Client: TOCLIENT_HELLO received with "
			<< "serialization_ver=" << (u32)serialization_ver
			<< ", auth_mechs=" << auth_mechs
			<< ", proto_ver=" << proto_ver
			<< ", compression_mode=" << compression_mode
			<< ". Doing auth with mech " << chosen_auth_mechanism << std::endl;

	if (!ser_ver_supported(serialization_ver)) {
		infostream << "Client: TOCLIENT_HELLO: Server sent "
				<< "unsupported ser_fmt_ver"<< std::endl;
		return;
	}

	m_server_ser_ver = serialization_ver;
	m_proto_ver = proto_ver;

	//TODO verify that username_legacy matches sent username, only
	// differs in casing (make both uppercase and compare)
	// This is only neccessary though when we actually want to add casing support

	if (m_chosen_auth_mech != AUTH_MECHANISM_NONE) {
		// we recieved a TOCLIENT_HELLO while auth was already going on
		errorstream << "Client: TOCLIENT_HELLO while auth was already going on"
			<< "(chosen_mech=" << m_chosen_auth_mech << ")." << std::endl;
		if (m_chosen_auth_mech == AUTH_MECHANISM_SRP ||
				m_chosen_auth_mech == AUTH_MECHANISM_LEGACY_PASSWORD) {
			srp_user_delete((SRPUser *) m_auth_data);
			m_auth_data = 0;
		}
	}

	// Authenticate using that method, or abort if there wasn't any method found
	if (chosen_auth_mechanism != AUTH_MECHANISM_NONE) {
		if (chosen_auth_mechanism == AUTH_MECHANISM_FIRST_SRP &&
				!m_simple_singleplayer_mode &&
				!getServerAddress().isLocalhost() &&
				g_settings->getBool("enable_register_confirmation")) {
			promptConfirmRegistration(chosen_auth_mechanism);
		} else {
			startAuth(chosen_auth_mechanism);
		}
	} else {
		m_chosen_auth_mech = AUTH_MECHANISM_NONE;
		m_access_denied = true;
		m_access_denied_reason = "Unknown";
		m_con->Disconnect();
	}

}

void Client::handleCommand_AuthAccept(NetworkPacket* pkt)
{
	deleteAuthData();

	v3f playerpos;
	*pkt >> playerpos >> m_map_seed >> m_recommended_send_interval
		>> m_sudo_auth_methods;

	playerpos -= v3f(0, BS / 2, 0);

	// Set player position
	LocalPlayer *player = m_env.getLocalPlayer();
	assert(player != NULL);
	player->setPosition(playerpos);

	infostream << "Client: received map seed: " << m_map_seed << std::endl;
	infostream << "Client: received recommended send interval "
					<< m_recommended_send_interval<<std::endl;

	// Reply to server
	std::string lang = gettext("LANG_CODE");
	if (lang == "LANG_CODE")
		lang = "";

	NetworkPacket resp_pkt(TOSERVER_INIT2, sizeof(u16) + lang.size());
	resp_pkt << lang;
	Send(&resp_pkt);

	m_state = LC_Init;
}
void Client::handleCommand_AcceptSudoMode(NetworkPacket* pkt)
{
	deleteAuthData();

	m_password = m_new_password;

	verbosestream << "Client: Recieved TOCLIENT_ACCEPT_SUDO_MODE." << std::endl;

	// send packet to actually set the password
	startAuth(AUTH_MECHANISM_FIRST_SRP);

	// reset again
	m_chosen_auth_mech = AUTH_MECHANISM_NONE;
}
void Client::handleCommand_DenySudoMode(NetworkPacket* pkt)
{
	ChatMessage *chatMessage = new ChatMessage(CHATMESSAGE_TYPE_SYSTEM,
			L"Password change denied. Password NOT changed.");
	pushToChatQueue(chatMessage);
	// reset everything and be sad
	deleteAuthData();
}

void Client::handleCommand_AccessDenied(NetworkPacket* pkt)
{
	// The server didn't like our password. Note, this needs
	// to be processed even if the serialisation format has
	// not been agreed yet, the same as TOCLIENT_INIT.
	m_access_denied = true;
	m_access_denied_reason = "Unknown";

	if (pkt->getCommand() != TOCLIENT_ACCESS_DENIED) {
		// 13/03/15 Legacy code from 0.4.12 and lesser but is still used
		// in some places of the server code
		if (pkt->getSize() >= 2) {
			std::wstring wide_reason;
			*pkt >> wide_reason;
			m_access_denied_reason = wide_to_utf8(wide_reason);
		}
		return;
	}

	if (pkt->getSize() < 1)
		return;

	u8 denyCode = SERVER_ACCESSDENIED_UNEXPECTED_DATA;
	*pkt >> denyCode;
	if (denyCode == SERVER_ACCESSDENIED_SHUTDOWN ||
			denyCode == SERVER_ACCESSDENIED_CRASH) {
		*pkt >> m_access_denied_reason;
		if (m_access_denied_reason.empty()) {
			m_access_denied_reason = accessDeniedStrings[denyCode];
		}
		u8 reconnect;
		*pkt >> reconnect;
		m_access_denied_reconnect = reconnect & 1;
	} else if (denyCode == SERVER_ACCESSDENIED_CUSTOM_STRING) {
		*pkt >> m_access_denied_reason;
	} else if (denyCode < SERVER_ACCESSDENIED_MAX) {
		m_access_denied_reason = accessDeniedStrings[denyCode];
	} else {
		// Allow us to add new error messages to the
		// protocol without raising the protocol version, if we want to.
		// Until then (which may be never), this is outside
		// of the defined protocol.
		*pkt >> m_access_denied_reason;
		if (m_access_denied_reason.empty()) {
			m_access_denied_reason = "Unknown";
		}
	}
}

void Client::handleCommand_RemoveNode(NetworkPacket* pkt)
{
	if (pkt->getSize() < 6)
		return;

	v3s16 p;
	*pkt >> p;
	removeNode(p);
}

void Client::handleCommand_AddNode(NetworkPacket* pkt)
{
	if (pkt->getSize() < 6 + MapNode::serializedLength(m_server_ser_ver))
		return;

	v3s16 p;
	*pkt >> p;

	MapNode n;
	n.deSerialize(pkt->getU8Ptr(6), m_server_ser_ver);

	bool remove_metadata = true;
	u32 index = 6 + MapNode::serializedLength(m_server_ser_ver);
	if ((pkt->getSize() >= index + 1) && pkt->getU8(index)) {
		remove_metadata = false;
	}

	addNode(p, n, remove_metadata);
}

void Client::handleCommand_NodemetaChanged(NetworkPacket *pkt)
{
	if (pkt->getSize() < 1)
		return;

	std::istringstream is(pkt->readLongString(), std::ios::binary);
	std::stringstream sstr;
	decompressZlib(is, sstr);

	NodeMetadataList meta_updates_list(false);
	meta_updates_list.deSerialize(sstr, m_itemdef, true);

	Map &map = m_env.getMap();
	for (NodeMetadataMap::const_iterator i = meta_updates_list.begin();
			i != meta_updates_list.end(); ++i) {
		v3s16 pos = i->first;

		if (map.isValidPosition(pos) &&
				map.setNodeMetadata(pos, i->second))
			continue; // Prevent from deleting metadata

		// Meta couldn't be set, unused metadata
		delete i->second;
	}
}

void Client::handleCommand_BlockData(NetworkPacket* pkt)
{
	// Ignore too small packet
	if (pkt->getSize() < 6)
		return;

	v3s16 p;
	*pkt >> p;

	std::string datastring(pkt->getString(6), pkt->getSize() - 6);
	std::istringstream istr(datastring, std::ios_base::binary);

	MapSector *sector;
	MapBlock *block;

	v2s16 p2d(p.X, p.Z);
	sector = m_env.getMap().emergeSector(p2d);

	assert(sector->getPos() == p2d);

	block = sector->getBlockNoCreateNoEx(p.Y);
	if (block) {
		/*
			Update an existing block
		*/
		block->deSerialize(istr, m_server_ser_ver, false);
		block->deSerializeNetworkSpecific(istr);
	}
	else {
		/*
			Create a new block
		*/
		block = new MapBlock(&m_env.getMap(), p, this);
		block->deSerialize(istr, m_server_ser_ver, false);
		block->deSerializeNetworkSpecific(istr);
		sector->insertBlock(block);
	}

	if (m_localdb) {
		ServerMap::saveBlock(block, m_localdb);
	}

	/*
		Add it to mesh update queue and set it to be acknowledged after update.
	*/
	addUpdateMeshTaskWithEdge(p, true);
}

void Client::handleCommand_Inventory(NetworkPacket* pkt)
{
	if (pkt->getSize() < 1)
		return;

	std::string datastring(pkt->getString(0), pkt->getSize());
	std::istringstream is(datastring, std::ios_base::binary);

	LocalPlayer *player = m_env.getLocalPlayer();
	assert(player != NULL);

	player->inventory.deSerialize(is);

	m_update_wielded_item = true;

	delete m_inventory_from_server;
	m_inventory_from_server = new Inventory(player->inventory);
	m_inventory_from_server_age = 0.0;
}

void Client::handleCommand_TimeOfDay(NetworkPacket* pkt)
{
	if (pkt->getSize() < 2)
		return;

	u16 time_of_day;

	*pkt >> time_of_day;

	time_of_day      = time_of_day % 24000;
	float time_speed = 0;

	if (pkt->getSize() >= 2 + 4) {
		*pkt >> time_speed;
	}
	else {
		// Old message; try to approximate speed of time by ourselves
		float time_of_day_f = (float)time_of_day / 24000.0f;
		float tod_diff_f = 0;

		if (time_of_day_f < 0.2 && m_last_time_of_day_f > 0.8)
			tod_diff_f = time_of_day_f - m_last_time_of_day_f + 1.0f;
		else
			tod_diff_f = time_of_day_f - m_last_time_of_day_f;

		m_last_time_of_day_f       = time_of_day_f;
		float time_diff            = m_time_of_day_update_timer;
		m_time_of_day_update_timer = 0;

		if (m_time_of_day_set) {
			time_speed = (3600.0f * 24.0f) * tod_diff_f / time_diff;
			infostream << "Client: Measured time_of_day speed (old format): "
					<< time_speed << " tod_diff_f=" << tod_diff_f
					<< " time_diff=" << time_diff << std::endl;
		}
	}

	// Update environment
	m_env.setTimeOfDay(time_of_day);
	m_env.setTimeOfDaySpeed(time_speed);
	m_time_of_day_set = true;

	u32 dr = m_env.getDayNightRatio();
	infostream << "Client: time_of_day=" << time_of_day
			<< " time_speed=" << time_speed
			<< " dr=" << dr << std::endl;
}

void Client::handleCommand_ChatMessage(NetworkPacket *pkt)
{
	/*
		u8 version
		u8 message_type
		u16 sendername length
		wstring sendername
		u16 length
		wstring message
	 */

	ChatMessage *chatMessage = new ChatMessage();
	u8 version, message_type;
	*pkt >> version >> message_type;

	if (version != 1 || message_type >= CHATMESSAGE_TYPE_MAX) {
		delete chatMessage;
		return;
	}

	u64 timestamp;
	*pkt >> chatMessage->sender >> chatMessage->message >> timestamp;
	chatMessage->timestamp = static_cast<std::time_t>(timestamp);

	chatMessage->type = (ChatMessageType) message_type;

	// @TODO send this to CSM using ChatMessage object
	if (modsLoaded() && m_script->on_receiving_message(
			wide_to_utf8(chatMessage->message))) {
		// Message was consumed by CSM and should not be handled by client
		delete chatMessage;
	} else {
		pushToChatQueue(chatMessage);
	}
}

void Client::handleCommand_ActiveObjectRemoveAdd(NetworkPacket* pkt)
{
	/*
		u16 count of removed objects
		for all removed objects {
			u16 id
		}
		u16 count of added objects
		for all added objects {
			u16 id
			u8 type
			u32 initialization data length
			string initialization data
		}
	*/

	try {
		u8 type;
		u16 removed_count, added_count, id;

		// Read removed objects
		*pkt >> removed_count;

		for (u16 i = 0; i < removed_count; i++) {
			*pkt >> id;
			m_env.removeActiveObject(id);
		}

		// Read added objects
		*pkt >> added_count;

		for (u16 i = 0; i < added_count; i++) {
			*pkt >> id >> type;
			m_env.addActiveObject(id, type, pkt->readLongString());
		}
	} catch (PacketError &e) {
		infostream << "handleCommand_ActiveObjectRemoveAdd: " << e.what()
				<< ". The packet is unreliable, ignoring" << std::endl;
	}

	// m_activeobjects_received is false before the first
	// TOCLIENT_ACTIVE_OBJECT_REMOVE_ADD packet is received
	m_activeobjects_received = true;
}

void Client::handleCommand_ActiveObjectMessages(NetworkPacket* pkt)
{
	/*
		for all objects
		{
			u16 id
			u16 message length
			string message
		}
	*/
	std::string datastring(pkt->getString(0), pkt->getSize());
	std::istringstream is(datastring, std::ios_base::binary);

	try {
		while (is.good()) {
			u16 id = readU16(is);
			if (!is.good())
				break;

			std::string message = deSerializeString(is);

			// Pass on to the environment
			m_env.processActiveObjectMessage(id, message);
		}
	} catch (SerializationError &e) {
		errorstream << "Client::handleCommand_ActiveObjectMessages: "
			<< "caught SerializationError: " << e.what() << std::endl;
	}
}

void Client::handleCommand_Movement(NetworkPacket* pkt)
{
	LocalPlayer *player = m_env.getLocalPlayer();
	assert(player != NULL);

	float mad, maa, maf, msw, mscr, msf, mscl, msj, lf, lfs, ls, g;

	*pkt >> mad >> maa >> maf >> msw >> mscr >> msf >> mscl >> msj
		>> lf >> lfs >> ls >> g;

	player->movement_acceleration_default   = mad * BS;
	player->movement_acceleration_air       = maa * BS;
	player->movement_acceleration_fast      = maf * BS;
	player->movement_speed_walk             = msw * BS;
	player->movement_speed_crouch           = mscr * BS;
	player->movement_speed_fast             = msf * BS;
	player->movement_speed_climb            = mscl * BS;
	player->movement_speed_jump             = msj * BS;
	player->movement_liquid_fluidity        = lf * BS;
	player->movement_liquid_fluidity_smooth = lfs * BS;
	player->movement_liquid_sink            = ls * BS;
	player->movement_gravity                = g * BS;
}

void Client::handleCommand_Fov(NetworkPacket *pkt)
{
	f32 fov;
	bool is_multiplier;
	*pkt >> fov >> is_multiplier;

	LocalPlayer *player = m_env.getLocalPlayer();
	player->setFov({ fov, is_multiplier });
}

void Client::handleCommand_HP(NetworkPacket *pkt)
{
	LocalPlayer *player = m_env.getLocalPlayer();
	assert(player != NULL);

	u16 oldhp = player->hp;

	u16 hp;
	*pkt >> hp;

	player->hp = hp;

	if (modsLoaded())
		m_script->on_hp_modification(hp);

	if (hp < oldhp) {
		// Add to ClientEvent queue
		ClientEvent *event = new ClientEvent();
		event->type = CE_PLAYER_DAMAGE;
		event->player_damage.amount = oldhp - hp;
		m_client_event_queue.push(event);
	}
}

void Client::handleCommand_Breath(NetworkPacket* pkt)
{
	LocalPlayer *player = m_env.getLocalPlayer();
	assert(player != NULL);

	u16 breath;

	*pkt >> breath;

	player->setBreath(breath);
}

void Client::handleCommand_MovePlayer(NetworkPacket* pkt)
{
	LocalPlayer *player = m_env.getLocalPlayer();
	assert(player != NULL);

	v3f pos;
	f32 pitch, yaw;

	*pkt >> pos >> pitch >> yaw;

	player->setPosition(pos);

	infostream << "Client got TOCLIENT_MOVE_PLAYER"
			<< " pos=(" << pos.X << "," << pos.Y << "," << pos.Z << ")"
			<< " pitch=" << pitch
			<< " yaw=" << yaw
			<< std::endl;

	/*
		Add to ClientEvent queue.
		This has to be sent to the main program because otherwise
		it would just force the pitch and yaw values to whatever
		the camera points to.
	*/
	ClientEvent *event = new ClientEvent();
	event->type = CE_PLAYER_FORCE_MOVE;
	event->player_force_move.pitch = pitch;
	event->player_force_move.yaw = yaw;
	m_client_event_queue.push(event);
}

void Client::handleCommand_DeathScreen(NetworkPacket* pkt)
{
	bool set_camera_point_target;
	v3f camera_point_target;

	*pkt >> set_camera_point_target;
	*pkt >> camera_point_target;

	ClientEvent *event = new ClientEvent();
	event->type                                = CE_DEATHSCREEN;
	event->deathscreen.set_camera_point_target = set_camera_point_target;
	event->deathscreen.camera_point_target_x   = camera_point_target.X;
	event->deathscreen.camera_point_target_y   = camera_point_target.Y;
	event->deathscreen.camera_point_target_z   = camera_point_target.Z;
	m_client_event_queue.push(event);
}

void Client::handleCommand_AnnounceMedia(NetworkPacket* pkt)
{
	u16 num_files;

	*pkt >> num_files;

	infostream << "Client: Received media announcement: packet size: "
			<< pkt->getSize() << std::endl;

	if (m_media_downloader == NULL ||
			m_media_downloader->isStarted()) {
		const char *problem = m_media_downloader ?
			"we already saw another announcement" :
			"all media has been received already";
		errorstream << "Client: Received media announcement but "
			<< problem << "! "
			<< " files=" << num_files
			<< " size=" << pkt->getSize() << std::endl;
		return;
	}

	// Mesh update thread must be stopped while
	// updating content definitions
	sanity_check(!m_mesh_update_thread.isRunning());

	for (u16 i = 0; i < num_files; i++) {
		std::string name, sha1_base64;

		*pkt >> name >> sha1_base64;

		std::string sha1_raw = base64_decode(sha1_base64);
		m_media_downloader->addFile(name, sha1_raw);
	}

	try {
		std::string str;

		*pkt >> str;

		Strfnd sf(str);
		while(!sf.at_end()) {
			std::string baseurl = trim(sf.next(","));
			if (!baseurl.empty())
				m_media_downloader->addRemoteServer(baseurl);
		}
	}
	catch(SerializationError& e) {
		// not supported by server or turned off
	}

	m_media_downloader->step(this);
}

void Client::handleCommand_Media(NetworkPacket* pkt)
{
	/*
		u16 command
		u16 total number of file bunches
		u16 index of this bunch
		u32 number of files in this bunch
		for each file {
			u16 length of name
			string name
			u32 length of data
			data
		}
	*/
	u16 num_bunches;
	u16 bunch_i;
	u32 num_files;

	*pkt >> num_bunches >> bunch_i >> num_files;

	infostream << "Client: Received files: bunch " << bunch_i << "/"
			<< num_bunches << " files=" << num_files
			<< " size=" << pkt->getSize() << std::endl;

	if (num_files == 0)
		return;

	if (!m_media_downloader || !m_media_downloader->isStarted()) {
		const char *problem = m_media_downloader ?
			"media has not been requested" :
			"all media has been received already";
		errorstream << "Client: Received media but "
			<< problem << "! "
			<< " bunch " << bunch_i << "/" << num_bunches
			<< " files=" << num_files
			<< " size=" << pkt->getSize() << std::endl;
		return;
	}

	// Mesh update thread must be stopped while
	// updating content definitions
	sanity_check(!m_mesh_update_thread.isRunning());

	for (u32 i=0; i < num_files; i++) {
		std::string name;

		*pkt >> name;

		std::string data = pkt->readLongString();

		m_media_downloader->conventionalTransferDone(
				name, data, this);
	}
}

void Client::handleCommand_NodeDef(NetworkPacket* pkt)
{
	infostream << "Client: Received node definitions: packet size: "
			<< pkt->getSize() << std::endl;

	// Mesh update thread must be stopped while
	// updating content definitions
	sanity_check(!m_mesh_update_thread.isRunning());

	// Decompress node definitions
	std::istringstream tmp_is(pkt->readLongString(), std::ios::binary);
	std::ostringstream tmp_os;
	decompressZlib(tmp_is, tmp_os);

	// Deserialize node definitions
	std::istringstream tmp_is2(tmp_os.str());
	m_nodedef->deSerialize(tmp_is2);
	m_nodedef_received = true;
}

void Client::handleCommand_ItemDef(NetworkPacket* pkt)
{
	infostream << "Client: Received item definitions: packet size: "
			<< pkt->getSize() << std::endl;

	// Mesh update thread must be stopped while
	// updating content definitions
	sanity_check(!m_mesh_update_thread.isRunning());

	// Decompress item definitions
	std::istringstream tmp_is(pkt->readLongString(), std::ios::binary);
	std::ostringstream tmp_os;
	decompressZlib(tmp_is, tmp_os);

	// Deserialize node definitions
	std::istringstream tmp_is2(tmp_os.str());
	m_itemdef->deSerialize(tmp_is2);
	m_itemdef_received = true;
}

void Client::handleCommand_PlaySound(NetworkPacket* pkt)
{
	/*
		[0] u32 server_id
		[4] u16 name length
		[6] char name[len]
		[ 6 + len] f32 gain
		[10 + len] u8 type
		[11 + len] (f32 * 3) pos
		[23 + len] u16 object_id
		[25 + len] bool loop
		[26 + len] f32 fade
		[30 + len] f32 pitch
		[34 + len] bool ephemeral
	*/

	s32 server_id;
	std::string name;

	float gain;
	u8 type; // 0=local, 1=positional, 2=object
	v3f pos;
	u16 object_id;
	bool loop;
	float fade = 0.0f;
	float pitch = 1.0f;
	bool ephemeral = false;

	*pkt >> server_id >> name >> gain >> type >> pos >> object_id >> loop;

	try {
		*pkt >> fade;
		*pkt >> pitch;
		*pkt >> ephemeral;
	} catch (PacketError &e) {};

	// Start playing
	int client_id = -1;
	switch(type) {
		case 0: // local
			client_id = m_sound->playSound(name, loop, gain, fade, pitch);
			break;
		case 1: // positional
			client_id = m_sound->playSoundAt(name, loop, gain, pos, pitch);
			break;
		case 2:
		{ // object
			ClientActiveObject *cao = m_env.getActiveObject(object_id);
			if (cao)
				pos = cao->getPosition();
			client_id = m_sound->playSoundAt(name, loop, gain, pos, pitch);
			break;
		}
		default:
			break;
	}

	if (client_id != -1) {
		// for ephemeral sounds, server_id is not meaningful
		if (!ephemeral) {
			m_sounds_server_to_client[server_id] = client_id;
			m_sounds_client_to_server[client_id] = server_id;
		}
		if (object_id != 0)
			m_sounds_to_objects[client_id] = object_id;
	}
}

void Client::handleCommand_StopSound(NetworkPacket* pkt)
{
	s32 server_id;

	*pkt >> server_id;

	std::unordered_map<s32, int>::iterator i = m_sounds_server_to_client.find(server_id);
	if (i != m_sounds_server_to_client.end()) {
		int client_id = i->second;
		m_sound->stopSound(client_id);
	}
}

void Client::handleCommand_FadeSound(NetworkPacket *pkt)
{
	s32 sound_id;
	float step;
	float gain;

	*pkt >> sound_id >> step >> gain;

	std::unordered_map<s32, int>::const_iterator i =
			m_sounds_server_to_client.find(sound_id);

	if (i != m_sounds_server_to_client.end())
		m_sound->fadeSound(i->second, step, gain);
}

void Client::handleCommand_Privileges(NetworkPacket* pkt)
{
	m_privileges.clear();
	infostream << "Client: Privileges updated: ";
	u16 num_privileges;

	*pkt >> num_privileges;

	for (u16 i = 0; i < num_privileges; i++) {
		std::string priv;

		*pkt >> priv;

		m_privileges.insert(priv);
		infostream << priv << " ";
	}
	infostream << std::endl;
}

void Client::handleCommand_InventoryFormSpec(NetworkPacket* pkt)
{
	LocalPlayer *player = m_env.getLocalPlayer();
	assert(player != NULL);

	// Store formspec in LocalPlayer
	player->inventory_formspec = pkt->readLongString();
}

void Client::handleCommand_DetachedInventory(NetworkPacket* pkt)
{
	std::string name;
	bool keep_inv = true;
	*pkt >> name >> keep_inv;

	infostream << "Client: Detached inventory update: \"" << name
		<< "\", mode=" << (keep_inv ? "update" : "remove") << std::endl;

	const auto &inv_it = m_detached_inventories.find(name);
	if (!keep_inv) {
		if (inv_it != m_detached_inventories.end()) {
			delete inv_it->second;
			m_detached_inventories.erase(inv_it);
		}
		return;
	}
	Inventory *inv = nullptr;
	if (inv_it == m_detached_inventories.end()) {
		inv = new Inventory(m_itemdef);
		m_detached_inventories[name] = inv;
	} else {
		inv = inv_it->second;
	}

	u16 ignore;
	*pkt >> ignore; // this used to be the length of the following string, ignore it

	std::string contents(pkt->getRemainingString(), pkt->getRemainingBytes());
	std::istringstream is(contents, std::ios::binary);
	inv->deSerialize(is);
}

void Client::handleCommand_ShowFormSpec(NetworkPacket* pkt)
{
	std::string formspec = pkt->readLongString();
	std::string formname;

	*pkt >> formname;

	ClientEvent *event = new ClientEvent();
	event->type = CE_SHOW_FORMSPEC;
	// pointer is required as event is a struct only!
	// adding a std:string to a struct isn't possible
	event->show_formspec.formspec = new std::string(formspec);
	event->show_formspec.formname = new std::string(formname);
	m_client_event_queue.push(event);
}

void Client::handleCommand_SpawnParticle(NetworkPacket* pkt)
{
	std::string datastring(pkt->getString(0), pkt->getSize());
	std::istringstream is(datastring, std::ios_base::binary);

	v3f pos                 = readV3F32(is);
	v3f vel                 = readV3F32(is);
	v3f acc                 = readV3F32(is);
	float expirationtime    = readF32(is);
	float size              = readF32(is);
	bool collisiondetection = readU8(is);
	std::string texture     = deSerializeLongString(is);

	bool vertical          = false;
	bool collision_removal = false;
	TileAnimationParams animation;
	animation.type         = TAT_NONE;
	u8 glow                = 0;
	bool object_collision  = false;
	try {
		vertical = readU8(is);
		collision_removal = readU8(is);
		animation.deSerialize(is, m_proto_ver);
		glow = readU8(is);
		object_collision = readU8(is);
	} catch (...) {}

	ClientEvent *event = new ClientEvent();
	event->type                              = CE_SPAWN_PARTICLE;
	event->spawn_particle.pos                = new v3f (pos);
	event->spawn_particle.vel                = new v3f (vel);
	event->spawn_particle.acc                = new v3f (acc);
	event->spawn_particle.expirationtime     = expirationtime;
	event->spawn_particle.size               = size;
	event->spawn_particle.collisiondetection = collisiondetection;
	event->spawn_particle.collision_removal  = collision_removal;
	event->spawn_particle.object_collision   = object_collision;
	event->spawn_particle.vertical           = vertical;
	event->spawn_particle.texture            = new std::string(texture);
	event->spawn_particle.animation          = animation;
	event->spawn_particle.glow               = glow;

	m_client_event_queue.push(event);
}

void Client::handleCommand_AddParticleSpawner(NetworkPacket* pkt)
{
	u16 amount;
	float spawntime;
	v3f minpos;
	v3f maxpos;
	v3f minvel;
	v3f maxvel;
	v3f minacc;
	v3f maxacc;
	float minexptime;
	float maxexptime;
	float minsize;
	float maxsize;
	bool collisiondetection;
	u32 server_id;

	*pkt >> amount >> spawntime >> minpos >> maxpos >> minvel >> maxvel
		>> minacc >> maxacc >> minexptime >> maxexptime >> minsize
		>> maxsize >> collisiondetection;

	std::string texture = pkt->readLongString();

	*pkt >> server_id;

	bool vertical          = false;
	bool collision_removal = false;
	u16 attached_id        = 0;
	TileAnimationParams animation;
	animation.type         = TAT_NONE;
	u8 glow                = 0;
	bool object_collision  = false;
	try {
		*pkt >> vertical;
		*pkt >> collision_removal;
		*pkt >> attached_id;

		// This is horrible but required (why are there two ways to deserialize pkts?)
		std::string datastring(pkt->getRemainingString(), pkt->getRemainingBytes());
		std::istringstream is(datastring, std::ios_base::binary);
		animation.deSerialize(is, m_proto_ver);
		glow = readU8(is);
		object_collision = readU8(is);
	} catch (...) {}

	auto event = new ClientEvent();
	event->type                                   = CE_ADD_PARTICLESPAWNER;
	event->add_particlespawner.amount             = amount;
	event->add_particlespawner.spawntime          = spawntime;
	event->add_particlespawner.minpos             = new v3f (minpos);
	event->add_particlespawner.maxpos             = new v3f (maxpos);
	event->add_particlespawner.minvel             = new v3f (minvel);
	event->add_particlespawner.maxvel             = new v3f (maxvel);
	event->add_particlespawner.minacc             = new v3f (minacc);
	event->add_particlespawner.maxacc             = new v3f (maxacc);
	event->add_particlespawner.minexptime         = minexptime;
	event->add_particlespawner.maxexptime         = maxexptime;
	event->add_particlespawner.minsize            = minsize;
	event->add_particlespawner.maxsize            = maxsize;
	event->add_particlespawner.collisiondetection = collisiondetection;
	event->add_particlespawner.collision_removal  = collision_removal;
	event->add_particlespawner.object_collision   = object_collision;
	event->add_particlespawner.attached_id        = attached_id;
	event->add_particlespawner.vertical           = vertical;
	event->add_particlespawner.texture            = new std::string(texture);
	event->add_particlespawner.id                 = server_id;
	event->add_particlespawner.animation          = animation;
	event->add_particlespawner.glow               = glow;

	m_client_event_queue.push(event);
}


void Client::handleCommand_DeleteParticleSpawner(NetworkPacket* pkt)
{
	u32 server_id;
	*pkt >> server_id;

	ClientEvent *event = new ClientEvent();
	event->type = CE_DELETE_PARTICLESPAWNER;
	event->delete_particlespawner.id = server_id;

	m_client_event_queue.push(event);
}

void Client::handleCommand_HudAdd(NetworkPacket* pkt)
{
	std::string datastring(pkt->getString(0), pkt->getSize());
	std::istringstream is(datastring, std::ios_base::binary);

	u32 server_id;
	u8 type;
	v2f pos;
	std::string name;
	v2f scale;
	std::string text;
	u32 number;
	u32 item;
	u32 dir;
	v2f align;
	v2f offset;
	v3f world_pos;
	v2s32 size;
	s16 z_index = 0;

	*pkt >> server_id >> type >> pos >> name >> scale >> text >> number >> item
		>> dir >> align >> offset;
	try {
		*pkt >> world_pos;
	}
	catch(SerializationError &e) {};

	try {
		*pkt >> size;
	} catch(SerializationError &e) {};

	try {
		*pkt >> z_index;
	}
	catch(PacketError &e) {}

	ClientEvent *event = new ClientEvent();
	event->type             = CE_HUDADD;
	event->hudadd.server_id = server_id;
	event->hudadd.type      = type;
	event->hudadd.pos       = new v2f(pos);
	event->hudadd.name      = new std::string(name);
	event->hudadd.scale     = new v2f(scale);
	event->hudadd.text      = new std::string(text);
	event->hudadd.number    = number;
	event->hudadd.item      = item;
	event->hudadd.dir       = dir;
	event->hudadd.align     = new v2f(align);
	event->hudadd.offset    = new v2f(offset);
	event->hudadd.world_pos = new v3f(world_pos);
	event->hudadd.size      = new v2s32(size);
	event->hudadd.z_index   = z_index;
	m_client_event_queue.push(event);
}

void Client::handleCommand_HudRemove(NetworkPacket* pkt)
{
	u32 server_id;

	*pkt >> server_id;

	auto i = m_hud_server_to_client.find(server_id);
	if (i != m_hud_server_to_client.end()) {
		int client_id = i->second;
		m_hud_server_to_client.erase(i);

		ClientEvent *event = new ClientEvent();
		event->type     = CE_HUDRM;
		event->hudrm.id = client_id;
		m_client_event_queue.push(event);
	}
}

void Client::handleCommand_HudChange(NetworkPacket* pkt)
{
	std::string sdata;
	v2f v2fdata;
	v3f v3fdata;
	u32 intdata = 0;
	v2s32 v2s32data;
	u32 server_id;
	u8 stat;

	*pkt >> server_id >> stat;

	if (stat == HUD_STAT_POS || stat == HUD_STAT_SCALE ||
		stat == HUD_STAT_ALIGN || stat == HUD_STAT_OFFSET)
		*pkt >> v2fdata;
	else if (stat == HUD_STAT_NAME || stat == HUD_STAT_TEXT)
		*pkt >> sdata;
	else if (stat == HUD_STAT_WORLD_POS)
		*pkt >> v3fdata;
	else if (stat == HUD_STAT_SIZE )
		*pkt >> v2s32data;
	else
		*pkt >> intdata;

	std::unordered_map<u32, u32>::const_iterator i = m_hud_server_to_client.find(server_id);
	if (i != m_hud_server_to_client.end()) {
		ClientEvent *event = new ClientEvent();
		event->type              = CE_HUDCHANGE;
		event->hudchange.id      = i->second;
		event->hudchange.stat    = (HudElementStat)stat;
		event->hudchange.v2fdata = new v2f(v2fdata);
		event->hudchange.v3fdata = new v3f(v3fdata);
		event->hudchange.sdata   = new std::string(sdata);
		event->hudchange.data    = intdata;
		event->hudchange.v2s32data = new v2s32(v2s32data);
		m_client_event_queue.push(event);
	}
}

void Client::handleCommand_HudSetFlags(NetworkPacket* pkt)
{
	u32 flags, mask;

	*pkt >> flags >> mask;

	LocalPlayer *player = m_env.getLocalPlayer();
	assert(player != NULL);

	bool was_minimap_visible = player->hud_flags & HUD_FLAG_MINIMAP_VISIBLE;
	bool was_minimap_radar_visible = player->hud_flags & HUD_FLAG_MINIMAP_RADAR_VISIBLE;

	player->hud_flags &= ~mask;
	player->hud_flags |= flags;

	m_minimap_disabled_by_server = !(player->hud_flags & HUD_FLAG_MINIMAP_VISIBLE);
	bool m_minimap_radar_disabled_by_server = !(player->hud_flags & HUD_FLAG_MINIMAP_RADAR_VISIBLE);

	// Hide minimap if it has been disabled by the server
	if (m_minimap && m_minimap_disabled_by_server && was_minimap_visible)
		// defers a minimap update, therefore only call it if really
		// needed, by checking that minimap was visible before
		m_minimap->setMinimapMode(MINIMAP_MODE_OFF);

	// Switch to surface mode if radar disabled by server
	if (m_minimap && m_minimap_radar_disabled_by_server && was_minimap_radar_visible)
		m_minimap->setMinimapMode(MINIMAP_MODE_SURFACEx1);
}

void Client::handleCommand_HudSetParam(NetworkPacket* pkt)
{
	u16 param; std::string value;

	*pkt >> param >> value;

	LocalPlayer *player = m_env.getLocalPlayer();
	assert(player != NULL);

	if (param == HUD_PARAM_HOTBAR_ITEMCOUNT && value.size() == 4) {
		s32 hotbar_itemcount = readS32((u8*) value.c_str());
		if (hotbar_itemcount > 0 && hotbar_itemcount <= HUD_HOTBAR_ITEMCOUNT_MAX)
			player->hud_hotbar_itemcount = hotbar_itemcount;
	}
	else if (param == HUD_PARAM_HOTBAR_IMAGE) {
		player->hotbar_image = value;
	}
	else if (param == HUD_PARAM_HOTBAR_SELECTED_IMAGE) {
		player->hotbar_selected_image = value;
	}
}

void Client::handleCommand_HudSetSky(NetworkPacket* pkt)
{
	if (m_proto_ver < 39) {
		// Handle Protocol 38 and below servers with old set_sky,
		// ensuring the classic look is kept.
		std::string datastring(pkt->getString(0), pkt->getSize());
		std::istringstream is(datastring, std::ios_base::binary);

		SkyboxParams skybox;
		skybox.bgcolor = video::SColor(readARGB8(is));
		skybox.type = std::string(deSerializeString(is));
		u16 count = readU16(is);

		for (size_t i = 0; i < count; i++)
			skybox.textures.emplace_back(deSerializeString(is));

		skybox.clouds = true;
		try {
			skybox.clouds = readU8(is);
		} catch (...) {}

		// Use default skybox settings:
		SkyboxDefaults sky_defaults;
		SunParams sun = sky_defaults.getSunDefaults();
		MoonParams moon = sky_defaults.getMoonDefaults();
		StarParams stars = sky_defaults.getStarDefaults();

		// Fix for "regular" skies, as color isn't kept:
		if (skybox.type == "regular") {
			skybox.sky_color = sky_defaults.getSkyColorDefaults();
			skybox.tint_type = "default";
			skybox.moon_tint = video::SColor(255, 255, 255, 255);
			skybox.sun_tint = video::SColor(255, 255, 255, 255);
		}
		else {
			sun.visible = false;
			sun.sunrise_visible = false;
			moon.visible = false;
			stars.visible = false;
		}

		// Skybox, sun, moon and stars ClientEvents:
		ClientEvent *sky_event = new ClientEvent();
		sky_event->type = CE_SET_SKY;
		sky_event->set_sky = new SkyboxParams(skybox);
		m_client_event_queue.push(sky_event);

		ClientEvent *sun_event = new ClientEvent();
		sun_event->type = CE_SET_SUN;
		sun_event->sun_params = new SunParams(sun);
		m_client_event_queue.push(sun_event);

		ClientEvent *moon_event = new ClientEvent();
		moon_event->type = CE_SET_MOON;
		moon_event->moon_params = new MoonParams(moon);
		m_client_event_queue.push(moon_event);

		ClientEvent *star_event = new ClientEvent();
		star_event->type = CE_SET_STARS;
		star_event->star_params = new StarParams(stars);
		m_client_event_queue.push(star_event);
	} else {
		SkyboxParams skybox;
		u16 texture_count;
		std::string texture;

		*pkt >> skybox.bgcolor >> skybox.type >> skybox.clouds >>
			skybox.sun_tint >> skybox.moon_tint >> skybox.tint_type;

		if (skybox.type == "skybox") {
			*pkt >> texture_count;
			for (int i = 0; i < texture_count; i++) {
				*pkt >> texture;
				skybox.textures.emplace_back(texture);
			}
		}
		else if (skybox.type == "regular") {
			*pkt >> skybox.sky_color.day_sky >> skybox.sky_color.day_horizon
				>> skybox.sky_color.dawn_sky >> skybox.sky_color.dawn_horizon
				>> skybox.sky_color.night_sky >> skybox.sky_color.night_horizon
				>> skybox.sky_color.indoors;
		}

		ClientEvent *event = new ClientEvent();
		event->type = CE_SET_SKY;
		event->set_sky = new SkyboxParams(skybox);
		m_client_event_queue.push(event);
	}
}

void Client::handleCommand_HudSetSun(NetworkPacket *pkt)
{
	SunParams sun;

	*pkt >> sun.visible >> sun.texture>> sun.tonemap
		>> sun.sunrise >> sun.sunrise_visible >> sun.scale;

	ClientEvent *event = new ClientEvent();
	event->type        = CE_SET_SUN;
	event->sun_params  = new SunParams(sun);
	m_client_event_queue.push(event);
}

void Client::handleCommand_HudSetMoon(NetworkPacket *pkt)
{
	MoonParams moon;

	*pkt >> moon.visible >> moon.texture
		>> moon.tonemap >> moon.scale;

	ClientEvent *event = new ClientEvent();
	event->type        = CE_SET_MOON;
	event->moon_params = new MoonParams(moon);
	m_client_event_queue.push(event);
}

void Client::handleCommand_HudSetStars(NetworkPacket *pkt)
{
	StarParams stars;

	*pkt >> stars.visible >> stars.count
		>> stars.starcolor >> stars.scale;

	ClientEvent *event = new ClientEvent();
	event->type        = CE_SET_STARS;
	event->star_params = new StarParams(stars);

	m_client_event_queue.push(event);
}

void Client::handleCommand_CloudParams(NetworkPacket* pkt)
{
	f32 density;
	video::SColor color_bright;
	video::SColor color_ambient;
	f32 height;
	f32 thickness;
	v2f speed;

	*pkt >> density >> color_bright >> color_ambient
			>> height >> thickness >> speed;

	ClientEvent *event = new ClientEvent();
	event->type                       = CE_CLOUD_PARAMS;
	event->cloud_params.density       = density;
	// use the underlying u32 representation, because we can't
	// use struct members with constructors here, and this way
	// we avoid using new() and delete() for no good reason
	event->cloud_params.color_bright  = color_bright.color;
	event->cloud_params.color_ambient = color_ambient.color;
	event->cloud_params.height        = height;
	event->cloud_params.thickness     = thickness;
	// same here: deconstruct to skip constructor
	event->cloud_params.speed_x       = speed.X;
	event->cloud_params.speed_y       = speed.Y;
	m_client_event_queue.push(event);
}

void Client::handleCommand_OverrideDayNightRatio(NetworkPacket* pkt)
{
	bool do_override;
	u16 day_night_ratio_u;

	*pkt >> do_override >> day_night_ratio_u;

	float day_night_ratio_f = (float)day_night_ratio_u / 65536;

	ClientEvent *event = new ClientEvent();
	event->type                                 = CE_OVERRIDE_DAY_NIGHT_RATIO;
	event->override_day_night_ratio.do_override = do_override;
	event->override_day_night_ratio.ratio_f     = day_night_ratio_f;
	m_client_event_queue.push(event);
}

void Client::handleCommand_LocalPlayerAnimations(NetworkPacket* pkt)
{
	LocalPlayer *player = m_env.getLocalPlayer();
	assert(player != NULL);

	*pkt >> player->local_animations[0];
	*pkt >> player->local_animations[1];
	*pkt >> player->local_animations[2];
	*pkt >> player->local_animations[3];
	*pkt >> player->local_animation_speed;
}

void Client::handleCommand_EyeOffset(NetworkPacket* pkt)
{
	LocalPlayer *player = m_env.getLocalPlayer();
	assert(player != NULL);

	*pkt >> player->eye_offset_first >> player->eye_offset_third;
}

void Client::handleCommand_UpdatePlayerList(NetworkPacket* pkt)
{
	u8 type;
	u16 num_players;
	*pkt >> type >> num_players;
	PlayerListModifer notice_type = (PlayerListModifer) type;

	for (u16 i = 0; i < num_players; i++) {
		std::string name;
		*pkt >> name;
		switch (notice_type) {
		case PLAYER_LIST_INIT:
		case PLAYER_LIST_ADD:
			m_env.addPlayerName(name);
			continue;
		case PLAYER_LIST_REMOVE:
			m_env.removePlayerName(name);
			continue;
		}
	}
}

void Client::handleCommand_SrpBytesSandB(NetworkPacket* pkt)
{
	if (m_chosen_auth_mech != AUTH_MECHANISM_SRP &&
			m_chosen_auth_mech != AUTH_MECHANISM_LEGACY_PASSWORD) {
		errorstream << "Client: Received SRP S_B login message,"
			<< " but wasn't supposed to (chosen_mech="
			<< m_chosen_auth_mech << ")." << std::endl;
		return;
	}

	char *bytes_M = 0;
	size_t len_M = 0;
	SRPUser *usr = (SRPUser *) m_auth_data;
	std::string s;
	std::string B;
	*pkt >> s >> B;

	infostream << "Client: Received TOCLIENT_SRP_BYTES_S_B." << std::endl;

	srp_user_process_challenge(usr, (const unsigned char *) s.c_str(), s.size(),
		(const unsigned char *) B.c_str(), B.size(),
		(unsigned char **) &bytes_M, &len_M);

	if ( !bytes_M ) {
		errorstream << "Client: SRP-6a S_B safety check violation!" << std::endl;
		return;
	}

	NetworkPacket resp_pkt(TOSERVER_SRP_BYTES_M, 0);
	resp_pkt << std::string(bytes_M, len_M);
	Send(&resp_pkt);
}

void Client::handleCommand_FormspecPrepend(NetworkPacket *pkt)
{
	LocalPlayer *player = m_env.getLocalPlayer();
	assert(player != NULL);

	// Store formspec in LocalPlayer
	*pkt >> player->formspec_prepend;
}

void Client::handleCommand_CSMRestrictionFlags(NetworkPacket *pkt)
{
	*pkt >> m_csm_restriction_flags >> m_csm_restriction_noderange;

	// Restrictions were received -> load mods if it's enabled
	// Note: this should be moved after mods receptions from server instead
	loadMods();
}

void Client::handleCommand_PlayerSpeed(NetworkPacket *pkt)
{
	v3f added_vel;

	*pkt >> added_vel;

	LocalPlayer *player = m_env.getLocalPlayer();
	assert(player != NULL);
	player->addVelocity(added_vel);
}

/*
 * Mod channels
 */

void Client::handleCommand_ModChannelMsg(NetworkPacket *pkt)
{
	std::string channel_name, sender, channel_msg;
	*pkt >> channel_name >> sender >> channel_msg;

	verbosestream << "Mod channel message received from server " << pkt->getPeerId()
		<< " on channel " << channel_name << ". sender: `" << sender << "`, message: "
		<< channel_msg << std::endl;

	if (!m_modchannel_mgr->channelRegistered(channel_name)) {
		verbosestream << "Server sent us messages on unregistered channel "
			<< channel_name << ", ignoring." << std::endl;
		return;
	}

	m_script->on_modchannel_message(channel_name, sender, channel_msg);
}

void Client::handleCommand_ModChannelSignal(NetworkPacket *pkt)
{
	u8 signal_tmp;
	ModChannelSignal signal;
	std::string channel;

	*pkt >> signal_tmp >> channel;

	signal = (ModChannelSignal)signal_tmp;

	bool valid_signal = true;
	// @TODO: send Signal to Lua API
	switch (signal) {
		case MODCHANNEL_SIGNAL_JOIN_OK:
			m_modchannel_mgr->setChannelState(channel, MODCHANNEL_STATE_READ_WRITE);
			infostream << "Server ack our mod channel join on channel `" << channel
				<< "`, joining." << std::endl;
			break;
		case MODCHANNEL_SIGNAL_JOIN_FAILURE:
			// Unable to join, remove channel
			m_modchannel_mgr->leaveChannel(channel, 0);
			infostream << "Server refused our mod channel join on channel `" << channel
				<< "`" << std::endl;
			break;
		case MODCHANNEL_SIGNAL_LEAVE_OK:
#ifndef NDEBUG
			infostream << "Server ack our mod channel leave on channel " << channel
				<< "`, leaving." << std::endl;
#endif
			break;
		case MODCHANNEL_SIGNAL_LEAVE_FAILURE:
			infostream << "Server refused our mod channel leave on channel `" << channel
				<< "`" << std::endl;
			break;
		case MODCHANNEL_SIGNAL_CHANNEL_NOT_REGISTERED:
#ifndef NDEBUG
			// Generally unused, but ensure we don't do an implementation error
			infostream << "Server tells us we sent a message on channel `" << channel
				<< "` but we are not registered. Message was dropped." << std::endl;
#endif
			break;
		case MODCHANNEL_SIGNAL_SET_STATE: {
			u8 state;
			*pkt >> state;

			if (state == MODCHANNEL_STATE_INIT || state >= MODCHANNEL_STATE_MAX) {
				infostream << "Received wrong channel state " << state
						<< ", ignoring." << std::endl;
				return;
			}

			m_modchannel_mgr->setChannelState(channel, (ModChannelState) state);
			infostream << "Server sets mod channel `" << channel
					<< "` in read-only mode." << std::endl;
			break;
		}
		default:
#ifndef NDEBUG
			warningstream << "Received unhandled mod channel signal ID "
				<< signal << ", ignoring." << std::endl;
#endif
			valid_signal = false;
			break;
	}

	// If signal is valid, forward it to client side mods
	if (valid_signal)
		m_script->on_modchannel_signal(channel, signal);
}