Fix: Data races on cursor state in OpenGL backends

[openttd-github.git] / src / network / network_server.cpp

/*
 * This file is part of OpenTTD.
 * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
 * OpenTTD 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 General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */

/** @file network_server.cpp Server part of the network protocol. */

#include "../stdafx.h"
#include "../strings_func.h"
#include "../date_func.h"
#include "network_admin.h"
#include "network_server.h"
#include "network_udp.h"
#include "network_base.h"
#include "../console_func.h"
#include "../company_base.h"
#include "../command_func.h"
#include "../saveload/saveload.h"
#include "../saveload/saveload_filter.h"
#include "../station_base.h"
#include "../genworld.h"
#include "../company_func.h"
#include "../company_gui.h"
#include "../roadveh.h"
#include "../order_backup.h"
#include "../core/pool_func.hpp"
#include "../core/random_func.hpp"
#include "../rev.h"
#include <mutex>
#include <condition_variable>

#include "../safeguards.h"


/* This file handles all the server-commands */

DECLARE_POSTFIX_INCREMENT(ClientID)
/** The identifier counter for new clients (is never decreased) */
static ClientID _network_client_id = CLIENT_ID_FIRST;

/** Make very sure the preconditions given in network_type.h are actually followed */
static_assert(MAX_CLIENT_SLOTS > MAX_CLIENTS);
/** Yes... */
static_assert(NetworkClientSocketPool::MAX_SIZE == MAX_CLIENT_SLOTS);

/** The pool with clients. */
NetworkClientSocketPool _networkclientsocket_pool("NetworkClientSocket");
INSTANTIATE_POOL_METHODS(NetworkClientSocket)

/** Instantiate the listen sockets. */
template SocketList TCPListenHandler<ServerNetworkGameSocketHandler, PACKET_SERVER_FULL, PACKET_SERVER_BANNED>::sockets;

/** Writing a savegame directly to a number of packets. */
struct PacketWriter : SaveFilter {
        ServerNetworkGameSocketHandler *cs; ///< Socket we are associated with.
        Packet *current;                    ///< The packet we're currently writing to.
        size_t total_size;                  ///< Total size of the compressed savegame.
        Packet *packets;                    ///< Packet queue of the savegame; send these "slowly" to the client.
        std::mutex mutex;                   ///< Mutex for making threaded saving safe.
        std::condition_variable exit_sig;   ///< Signal for threaded destruction of this packet writer.

        /**
         * Create the packet writer.
         * @param cs The socket handler we're making the packets for.
         */
        PacketWriter(ServerNetworkGameSocketHandler *cs) : SaveFilter(nullptr), cs(cs), current(nullptr), total_size(0), packets(nullptr)
        {
        }

        /** Make sure everything is cleaned up. */
        ~PacketWriter()
        {
                std::unique_lock<std::mutex> lock(this->mutex);

                if (this->cs != nullptr) this->exit_sig.wait(lock);

                /* This must all wait until the Destroy function is called. */

                while (this->packets != nullptr) {
                        Packet *p = this->packets->next;
                        delete this->packets;
                        this->packets = p;
                }

                delete this->current;
        }

        /**
         * Begin the destruction of this packet writer. It can happen in two ways:
         * in the first case the client disconnected while saving the map. In this
         * case the saving has not finished and killed this PacketWriter. In that
         * case we simply set cs to nullptr, triggering the appending to fail due to
         * the connection problem and eventually triggering the destructor. In the
         * second case the destructor is already called, and it is waiting for our
         * signal which we will send. Only then the packets will be removed by the
         * destructor.
         */
        void Destroy()
        {
                std::unique_lock<std::mutex> lock(this->mutex);

                this->cs = nullptr;

                this->exit_sig.notify_all();
                lock.unlock();

                /* Make sure the saving is completely cancelled. Yes,
                 * we need to handle the save finish as well as the
                 * next connection might just be requesting a map. */
                WaitTillSaved();
                ProcessAsyncSaveFinish();
        }

        /**
         * Checks whether there are packets.
         * It's not 100% threading safe, but this is only asked for when checking
         * whether there still is something to send. Then another call will be made
         * to actually get the Packet, which will be the only one popping packets
         * and thus eventually setting this on false.
         */
        bool HasPackets()
        {
                return this->packets != nullptr;
        }

        /**
         * Pop a single created packet from the queue with packets.
         */
        Packet *PopPacket()
        {
                std::lock_guard<std::mutex> lock(this->mutex);

                Packet *p = this->packets;
                this->packets = p->next;
                p->next = nullptr;

                return p;
        }

        /** Append the current packet to the queue. */
        void AppendQueue()
        {
                if (this->current == nullptr) return;

                Packet **p = &this->packets;
                while (*p != nullptr) {
                        p = &(*p)->next;
                }
                *p = this->current;

                this->current = nullptr;
        }

        /** Prepend the current packet to the queue. */
        void PrependQueue()
        {
                if (this->current == nullptr) return;

                this->current->next = this->packets;
                this->packets = this->current;
                this->current = nullptr;
        }

        void Write(byte *buf, size_t size) override
        {
                /* We want to abort the saving when the socket is closed. */
                if (this->cs == nullptr) SlError(STR_NETWORK_ERROR_LOSTCONNECTION);

                if (this->current == nullptr) this->current = new Packet(PACKET_SERVER_MAP_DATA);

                std::lock_guard<std::mutex> lock(this->mutex);

                byte *bufe = buf + size;
                while (buf != bufe) {
                        size_t to_write = std::min<size_t>(SEND_MTU - this->current->size, bufe - buf);
                        memcpy(this->current->buffer + this->current->size, buf, to_write);
                        this->current->size += (PacketSize)to_write;
                        buf += to_write;

                        if (this->current->size == SEND_MTU) {
                                this->AppendQueue();
                                if (buf != bufe) this->current = new Packet(PACKET_SERVER_MAP_DATA);
                        }
                }

                this->total_size += size;
        }

        void Finish() override
        {
                /* We want to abort the saving when the socket is closed. */
                if (this->cs == nullptr) SlError(STR_NETWORK_ERROR_LOSTCONNECTION);

                std::lock_guard<std::mutex> lock(this->mutex);

                /* Make sure the last packet is flushed. */
                this->AppendQueue();

                /* Add a packet stating that this is the end to the queue. */
                this->current = new Packet(PACKET_SERVER_MAP_DONE);
                this->AppendQueue();

                /* Fast-track the size to the client. */
                this->current = new Packet(PACKET_SERVER_MAP_SIZE);
                this->current->Send_uint32((uint32)this->total_size);
                this->PrependQueue();
        }
};


/**
 * Create a new socket for the server side of the game connection.
 * @param s The socket to connect with.
 */
ServerNetworkGameSocketHandler::ServerNetworkGameSocketHandler(SOCKET s) : NetworkGameSocketHandler(s)
{
        this->status = STATUS_INACTIVE;
        this->client_id = _network_client_id++;
        this->receive_limit = _settings_client.network.bytes_per_frame_burst;

        /* The Socket and Info pools need to be the same in size. After all,
         * each Socket will be associated with at most one Info object. As
         * such if the Socket was allocated the Info object can as well. */
        static_assert(NetworkClientSocketPool::MAX_SIZE == NetworkClientInfoPool::MAX_SIZE);
}

/**
 * Clear everything related to this client.
 */
ServerNetworkGameSocketHandler::~ServerNetworkGameSocketHandler()
{
        if (_redirect_console_to_client == this->client_id) _redirect_console_to_client = INVALID_CLIENT_ID;
        OrderBackup::ResetUser(this->client_id);

        if (this->savegame != nullptr) {
                this->savegame->Destroy();
                this->savegame = nullptr;
        }
}

Packet *ServerNetworkGameSocketHandler::ReceivePacket()
{
        /* Only allow receiving when we have some buffer free; this value
         * can go negative, but eventually it will become positive again. */
        if (this->receive_limit <= 0) return nullptr;

        /* We can receive a packet, so try that and if needed account for
         * the amount of received data. */
        Packet *p = this->NetworkTCPSocketHandler::ReceivePacket();
        if (p != nullptr) this->receive_limit -= p->size;
        return p;
}

NetworkRecvStatus ServerNetworkGameSocketHandler::CloseConnection(NetworkRecvStatus status)
{
        assert(status != NETWORK_RECV_STATUS_OKAY);
        /*
         * Sending a message just before leaving the game calls cs->SendPackets.
         * This might invoke this function, which means that when we close the
         * connection after cs->SendPackets we will close an already closed
         * connection. This handles that case gracefully without having to make
         * that code any more complex or more aware of the validity of the socket.
         */
        if (this->sock == INVALID_SOCKET) return status;

        if (status != NETWORK_RECV_STATUS_CONN_LOST && status != NETWORK_RECV_STATUS_SERVER_ERROR && !this->HasClientQuit() && this->status >= STATUS_AUTHORIZED) {
                /* We did not receive a leave message from this client... */
                char client_name[NETWORK_CLIENT_NAME_LENGTH];

                this->GetClientName(client_name, lastof(client_name));

                NetworkTextMessage(NETWORK_ACTION_LEAVE, CC_DEFAULT, false, client_name, nullptr, STR_NETWORK_ERROR_CLIENT_CONNECTION_LOST);

                /* Inform other clients of this... strange leaving ;) */
                for (NetworkClientSocket *new_cs : NetworkClientSocket::Iterate()) {
                        if (new_cs->status > STATUS_AUTHORIZED && this != new_cs) {
                                new_cs->SendErrorQuit(this->client_id, NETWORK_ERROR_CONNECTION_LOST);
                        }
                }
        }

        /* If we were transfering a map to this client, stop the savegame creation
         * process and queue the next client to receive the map. */
        if (this->status == STATUS_MAP) {
                /* Ensure the saving of the game is stopped too. */
                this->savegame->Destroy();
                this->savegame = nullptr;

                this->CheckNextClientToSendMap(this);
        }

        NetworkAdminClientError(this->client_id, NETWORK_ERROR_CONNECTION_LOST);
        DEBUG(net, 1, "Closed client connection %d", this->client_id);

        /* We just lost one client :( */
        if (this->status >= STATUS_AUTHORIZED) _network_game_info.clients_on--;
        extern byte _network_clients_connected;
        _network_clients_connected--;

        DeleteWindowById(WC_CLIENT_LIST_POPUP, this->client_id);
        SetWindowDirty(WC_CLIENT_LIST, 0);

        this->SendPackets(true);

        delete this->GetInfo();
        delete this;

        return status;
}

/**
 * Whether an connection is allowed or not at this moment.
 * @return true if the connection is allowed.
 */
/* static */ bool ServerNetworkGameSocketHandler::AllowConnection()
{
        extern byte _network_clients_connected;
        bool accept = _network_clients_connected < MAX_CLIENTS && _network_game_info.clients_on < _settings_client.network.max_clients;

        /* We can't go over the MAX_CLIENTS limit here. However, the
         * pool must have place for all clients and ourself. */
        static_assert(NetworkClientSocketPool::MAX_SIZE == MAX_CLIENTS + 1);
        assert(!accept || ServerNetworkGameSocketHandler::CanAllocateItem());
        return accept;
}

/** Send the packets for the server sockets. */
/* static */ void ServerNetworkGameSocketHandler::Send()
{
        for (NetworkClientSocket *cs : NetworkClientSocket::Iterate()) {
                if (cs->writable) {
                        if (cs->SendPackets() != SPS_CLOSED && cs->status == STATUS_MAP) {
                                /* This client is in the middle of a map-send, call the function for that */
                                cs->SendMap();
                        }
                }
        }
}

static void NetworkHandleCommandQueue(NetworkClientSocket *cs);

/***********
 * Sending functions
 *   DEF_SERVER_SEND_COMMAND has parameter: NetworkClientSocket *cs
 ************/

/**
 * Send the client information about a client.
 * @param ci The client to send information about.
 */
NetworkRecvStatus ServerNetworkGameSocketHandler::SendClientInfo(NetworkClientInfo *ci)
{
        if (ci->client_id != INVALID_CLIENT_ID) {
                Packet *p = new Packet(PACKET_SERVER_CLIENT_INFO);
                p->Send_uint32(ci->client_id);
                p->Send_uint8 (ci->client_playas);
                p->Send_string(ci->client_name);

                this->SendPacket(p);
        }
        return NETWORK_RECV_STATUS_OKAY;
}

/** Send the client information about the companies. */
NetworkRecvStatus ServerNetworkGameSocketHandler::SendCompanyInfo()
{
        /* Fetch the latest version of the stats */
        NetworkCompanyStats company_stats[MAX_COMPANIES];
        NetworkPopulateCompanyStats(company_stats);

        /* Make a list of all clients per company */
        char clients[MAX_COMPANIES][NETWORK_CLIENTS_LENGTH];
        memset(clients, 0, sizeof(clients));

        /* Add the local player (if not dedicated) */
        const NetworkClientInfo *ci = NetworkClientInfo::GetByClientID(CLIENT_ID_SERVER);
        if (ci != nullptr && Company::IsValidID(ci->client_playas)) {
                strecpy(clients[ci->client_playas], ci->client_name, lastof(clients[ci->client_playas]));
        }

        for (NetworkClientSocket *csi : NetworkClientSocket::Iterate()) {
                char client_name[NETWORK_CLIENT_NAME_LENGTH];

                ((ServerNetworkGameSocketHandler*)csi)->GetClientName(client_name, lastof(client_name));

                ci = csi->GetInfo();
                if (ci != nullptr && Company::IsValidID(ci->client_playas)) {
                        if (!StrEmpty(clients[ci->client_playas])) {
                                strecat(clients[ci->client_playas], ", ", lastof(clients[ci->client_playas]));
                        }

                        strecat(clients[ci->client_playas], client_name, lastof(clients[ci->client_playas]));
                }
        }

        /* Now send the data */

        Packet *p;

        for (const Company *company : Company::Iterate()) {
                p = new Packet(PACKET_SERVER_COMPANY_INFO);

                p->Send_uint8 (NETWORK_COMPANY_INFO_VERSION);
                p->Send_bool  (true);
                this->SendCompanyInformation(p, company, &company_stats[company->index]);

                if (StrEmpty(clients[company->index])) {
                        p->Send_string("<none>");
                } else {
                        p->Send_string(clients[company->index]);
                }

                this->SendPacket(p);
        }

        p = new Packet(PACKET_SERVER_COMPANY_INFO);

        p->Send_uint8 (NETWORK_COMPANY_INFO_VERSION);
        p->Send_bool  (false);

        this->SendPacket(p);
        return NETWORK_RECV_STATUS_OKAY;
}

/**
 * Send an error to the client, and close its connection.
 * @param error The error to disconnect for.
 * @param reason In case of kicking a client, specifies the reason for kicking the client.
 */
NetworkRecvStatus ServerNetworkGameSocketHandler::SendError(NetworkErrorCode error, const char *reason)
{
        char str[100];
        Packet *p = new Packet(PACKET_SERVER_ERROR);

        p->Send_uint8(error);
        if (reason != nullptr) p->Send_string(reason);
        this->SendPacket(p);

        StringID strid = GetNetworkErrorMsg(error);
        GetString(str, strid, lastof(str));

        /* Only send when the current client was in game */
        if (this->status > STATUS_AUTHORIZED) {
                char client_name[NETWORK_CLIENT_NAME_LENGTH];

                this->GetClientName(client_name, lastof(client_name));

                DEBUG(net, 1, "'%s' made an error and has been disconnected. Reason: '%s'", client_name, str);

                if (error == NETWORK_ERROR_KICKED && reason != nullptr) {
                        NetworkTextMessage(NETWORK_ACTION_KICKED, CC_DEFAULT, false, client_name, reason, strid);
                } else {
                        NetworkTextMessage(NETWORK_ACTION_LEAVE, CC_DEFAULT, false, client_name, nullptr, strid);
                }

                for (NetworkClientSocket *new_cs : NetworkClientSocket::Iterate()) {
                        if (new_cs->status >= STATUS_AUTHORIZED && new_cs != this) {
                                /* Some errors we filter to a more general error. Clients don't have to know the real
                                 *  reason a joining failed. */
                                if (error == NETWORK_ERROR_NOT_AUTHORIZED || error == NETWORK_ERROR_NOT_EXPECTED || error == NETWORK_ERROR_WRONG_REVISION) {
                                        error = NETWORK_ERROR_ILLEGAL_PACKET;
                                }
                                new_cs->SendErrorQuit(this->client_id, error);
                        }
                }

                NetworkAdminClientError(this->client_id, error);
        } else {
                DEBUG(net, 1, "Client %d made an error and has been disconnected. Reason: '%s'", this->client_id, str);
        }

        /* The client made a mistake, so drop his connection now! */
        return this->CloseConnection(NETWORK_RECV_STATUS_SERVER_ERROR);
}

/** Send the check for the NewGRFs. */
NetworkRecvStatus ServerNetworkGameSocketHandler::SendNewGRFCheck()
{
        Packet *p = new Packet(PACKET_SERVER_CHECK_NEWGRFS);
        const GRFConfig *c;
        uint grf_count = 0;

        for (c = _grfconfig; c != nullptr; c = c->next) {
                if (!HasBit(c->flags, GCF_STATIC)) grf_count++;
        }

        p->Send_uint8 (grf_count);
        for (c = _grfconfig; c != nullptr; c = c->next) {
                if (!HasBit(c->flags, GCF_STATIC)) this->SendGRFIdentifier(p, &c->ident);
        }

        this->SendPacket(p);
        return NETWORK_RECV_STATUS_OKAY;
}

/** Request the game password. */
NetworkRecvStatus ServerNetworkGameSocketHandler::SendNeedGamePassword()
{
        /* Invalid packet when status is STATUS_AUTH_GAME or higher */
        if (this->status >= STATUS_AUTH_GAME) return this->CloseConnection(NETWORK_RECV_STATUS_MALFORMED_PACKET);

        this->status = STATUS_AUTH_GAME;
        /* Reset 'lag' counters */
        this->last_frame = this->last_frame_server = _frame_counter;

        Packet *p = new Packet(PACKET_SERVER_NEED_GAME_PASSWORD);
        this->SendPacket(p);
        return NETWORK_RECV_STATUS_OKAY;
}

/** Request the company password. */
NetworkRecvStatus ServerNetworkGameSocketHandler::SendNeedCompanyPassword()
{
        /* Invalid packet when status is STATUS_AUTH_COMPANY or higher */
        if (this->status >= STATUS_AUTH_COMPANY) return this->CloseConnection(NETWORK_RECV_STATUS_MALFORMED_PACKET);

        this->status = STATUS_AUTH_COMPANY;
        /* Reset 'lag' counters */
        this->last_frame = this->last_frame_server = _frame_counter;

        Packet *p = new Packet(PACKET_SERVER_NEED_COMPANY_PASSWORD);
        p->Send_uint32(_settings_game.game_creation.generation_seed);
        p->Send_string(_settings_client.network.network_id);
        this->SendPacket(p);
        return NETWORK_RECV_STATUS_OKAY;
}

/** Send the client a welcome message with some basic information. */
NetworkRecvStatus ServerNetworkGameSocketHandler::SendWelcome()
{
        Packet *p;

        /* Invalid packet when status is AUTH or higher */
        if (this->status >= STATUS_AUTHORIZED) return this->CloseConnection(NETWORK_RECV_STATUS_MALFORMED_PACKET);

        this->status = STATUS_AUTHORIZED;
        /* Reset 'lag' counters */
        this->last_frame = this->last_frame_server = _frame_counter;

        _network_game_info.clients_on++;

        p = new Packet(PACKET_SERVER_WELCOME);
        p->Send_uint32(this->client_id);
        p->Send_uint32(_settings_game.game_creation.generation_seed);
        p->Send_string(_settings_client.network.network_id);
        this->SendPacket(p);

        /* Transmit info about all the active clients */
        for (NetworkClientSocket *new_cs : NetworkClientSocket::Iterate()) {
                if (new_cs != this && new_cs->status >= STATUS_AUTHORIZED) {
                        this->SendClientInfo(new_cs->GetInfo());
                }
        }
        /* Also send the info of the server */
        return this->SendClientInfo(NetworkClientInfo::GetByClientID(CLIENT_ID_SERVER));
}

/** Tell the client that its put in a waiting queue. */
NetworkRecvStatus ServerNetworkGameSocketHandler::SendWait()
{
        int waiting = 1; // current player getting the map counts as 1
        Packet *p;

        /* Count how many clients are waiting in the queue, in front of you! */
        for (NetworkClientSocket *new_cs : NetworkClientSocket::Iterate()) {
                if (new_cs->status != STATUS_MAP_WAIT) continue;
                if (new_cs->GetInfo()->join_date < this->GetInfo()->join_date || (new_cs->GetInfo()->join_date == this->GetInfo()->join_date && new_cs->client_id < this->client_id)) waiting++;
        }

        p = new Packet(PACKET_SERVER_WAIT);
        p->Send_uint8(waiting);
        this->SendPacket(p);
        return NETWORK_RECV_STATUS_OKAY;
}

void ServerNetworkGameSocketHandler::CheckNextClientToSendMap(NetworkClientSocket *ignore_cs)
{
        /* Find the best candidate for joining, i.e. the first joiner. */
        NetworkClientSocket *best = nullptr;
        for (NetworkClientSocket *new_cs : NetworkClientSocket::Iterate()) {
                if (ignore_cs == new_cs) continue;

                if (new_cs->status == STATUS_MAP_WAIT) {
                        if (best == nullptr || best->GetInfo()->join_date > new_cs->GetInfo()->join_date || (best->GetInfo()->join_date == new_cs->GetInfo()->join_date && best->client_id > new_cs->client_id)) {
                                best = new_cs;
                        }
                }
        }

        /* Is there someone else to join? */
        if (best != nullptr) {
                /* Let the first start joining. */
                best->status = STATUS_AUTHORIZED;
                best->SendMap();

                /* And update the rest. */
                for (NetworkClientSocket *new_cs : NetworkClientSocket::Iterate()) {
                        if (new_cs->status == STATUS_MAP_WAIT) new_cs->SendWait();
                }
        }
}

/** This sends the map to the client */
NetworkRecvStatus ServerNetworkGameSocketHandler::SendMap()
{
        static uint sent_packets; // How many packets we did send successfully last time

        if (this->status < STATUS_AUTHORIZED) {
                /* Illegal call, return error and ignore the packet */
                return this->SendError(NETWORK_ERROR_NOT_AUTHORIZED);
        }

        if (this->status == STATUS_AUTHORIZED) {
                this->savegame = new PacketWriter(this);

                /* Now send the _frame_counter and how many packets are coming */
                Packet *p = new Packet(PACKET_SERVER_MAP_BEGIN);
                p->Send_uint32(_frame_counter);
                this->SendPacket(p);

                NetworkSyncCommandQueue(this);
                this->status = STATUS_MAP;
                /* Mark the start of download */
                this->last_frame = _frame_counter;
                this->last_frame_server = _frame_counter;

                sent_packets = 4; // We start with trying 4 packets

                /* Make a dump of the current game */
                if (SaveWithFilter(this->savegame, true) != SL_OK) usererror("network savedump failed");
        }

        if (this->status == STATUS_MAP) {
                bool last_packet = false;
                bool has_packets = false;

                for (uint i = 0; (has_packets = this->savegame->HasPackets()) && i < sent_packets; i++) {
                        Packet *p = this->savegame->PopPacket();
                        last_packet = p->buffer[2] == PACKET_SERVER_MAP_DONE;

                        this->SendPacket(p);

                        if (last_packet) {
                                /* There is no more data, so break the for */
                                break;
                        }
                }

                if (last_packet) {
                        /* Done reading, make sure saving is done as well */
                        this->savegame->Destroy();
                        this->savegame = nullptr;

                        /* Set the status to DONE_MAP, no we will wait for the client
                         *  to send it is ready (maybe that happens like never ;)) */
                        this->status = STATUS_DONE_MAP;

                        this->CheckNextClientToSendMap();
                }

                switch (this->SendPackets()) {
                        case SPS_CLOSED:
                                return NETWORK_RECV_STATUS_CONN_LOST;

                        case SPS_ALL_SENT:
                                /* All are sent, increase the sent_packets */
                                if (has_packets) sent_packets *= 2;
                                break;

                        case SPS_PARTLY_SENT:
                                /* Only a part is sent; leave the transmission state. */
                                break;

                        case SPS_NONE_SENT:
                                /* Not everything is sent, decrease the sent_packets */
                                if (sent_packets > 1) sent_packets /= 2;
                                break;
                }
        }
        return NETWORK_RECV_STATUS_OKAY;
}

/**
 * Tell that a client joined.
 * @param client_id The client that joined.
 */
NetworkRecvStatus ServerNetworkGameSocketHandler::SendJoin(ClientID client_id)
{
        Packet *p = new Packet(PACKET_SERVER_JOIN);

        p->Send_uint32(client_id);

        this->SendPacket(p);
        return NETWORK_RECV_STATUS_OKAY;
}

/** Tell the client that they may run to a particular frame. */
NetworkRecvStatus ServerNetworkGameSocketHandler::SendFrame()
{
        Packet *p = new Packet(PACKET_SERVER_FRAME);
        p->Send_uint32(_frame_counter);
        p->Send_uint32(_frame_counter_max);
#ifdef ENABLE_NETWORK_SYNC_EVERY_FRAME
        p->Send_uint32(_sync_seed_1);
#ifdef NETWORK_SEND_DOUBLE_SEED
        p->Send_uint32(_sync_seed_2);
#endif
#endif

        /* If token equals 0, we need to make a new token and send that. */
        if (this->last_token == 0) {
                this->last_token = InteractiveRandomRange(UINT8_MAX - 1) + 1;
                p->Send_uint8(this->last_token);
        }

        this->SendPacket(p);
        return NETWORK_RECV_STATUS_OKAY;
}

/** Request the client to sync. */
NetworkRecvStatus ServerNetworkGameSocketHandler::SendSync()
{
        Packet *p = new Packet(PACKET_SERVER_SYNC);
        p->Send_uint32(_frame_counter);
        p->Send_uint32(_sync_seed_1);

#ifdef NETWORK_SEND_DOUBLE_SEED
        p->Send_uint32(_sync_seed_2);
#endif
        this->SendPacket(p);
        return NETWORK_RECV_STATUS_OKAY;
}

/**
 * Send a command to the client to execute.
 * @param cp The command to send.
 */
NetworkRecvStatus ServerNetworkGameSocketHandler::SendCommand(const CommandPacket *cp)
{
        Packet *p = new Packet(PACKET_SERVER_COMMAND);

        this->NetworkGameSocketHandler::SendCommand(p, cp);
        p->Send_uint32(cp->frame);
        p->Send_bool  (cp->my_cmd);

        this->SendPacket(p);
        return NETWORK_RECV_STATUS_OKAY;
}

/**
 * Send a chat message.
 * @param action The action associated with the message.
 * @param client_id The origin of the chat message.
 * @param self_send Whether we did send the message.
 * @param msg The actual message.
 * @param data Arbitrary extra data.
 */
NetworkRecvStatus ServerNetworkGameSocketHandler::SendChat(NetworkAction action, ClientID client_id, bool self_send, const char *msg, int64 data)
{
        if (this->status < STATUS_PRE_ACTIVE) return NETWORK_RECV_STATUS_OKAY;

        Packet *p = new Packet(PACKET_SERVER_CHAT);

        p->Send_uint8 (action);
        p->Send_uint32(client_id);
        p->Send_bool  (self_send);
        p->Send_string(msg);
        p->Send_uint64(data);

        this->SendPacket(p);
        return NETWORK_RECV_STATUS_OKAY;
}

/**
 * Tell the client another client quit with an error.
 * @param client_id The client that quit.
 * @param errorno The reason the client quit.
 */
NetworkRecvStatus ServerNetworkGameSocketHandler::SendErrorQuit(ClientID client_id, NetworkErrorCode errorno)
{
        Packet *p = new Packet(PACKET_SERVER_ERROR_QUIT);

        p->Send_uint32(client_id);
        p->Send_uint8 (errorno);

        this->SendPacket(p);
        return NETWORK_RECV_STATUS_OKAY;
}

/**
 * Tell the client another client quit.
 * @param client_id The client that quit.
 */
NetworkRecvStatus ServerNetworkGameSocketHandler::SendQuit(ClientID client_id)
{
        Packet *p = new Packet(PACKET_SERVER_QUIT);

        p->Send_uint32(client_id);

        this->SendPacket(p);
        return NETWORK_RECV_STATUS_OKAY;
}

/** Tell the client we're shutting down. */
NetworkRecvStatus ServerNetworkGameSocketHandler::SendShutdown()
{
        Packet *p = new Packet(PACKET_SERVER_SHUTDOWN);
        this->SendPacket(p);
        return NETWORK_RECV_STATUS_OKAY;
}

/** Tell the client we're starting a new game. */
NetworkRecvStatus ServerNetworkGameSocketHandler::SendNewGame()
{
        Packet *p = new Packet(PACKET_SERVER_NEWGAME);
        this->SendPacket(p);
        return NETWORK_RECV_STATUS_OKAY;
}

/**
 * Send the result of a console action.
 * @param colour The colour of the result.
 * @param command The command that was executed.
 */
NetworkRecvStatus ServerNetworkGameSocketHandler::SendRConResult(uint16 colour, const char *command)
{
        Packet *p = new Packet(PACKET_SERVER_RCON);

        p->Send_uint16(colour);
        p->Send_string(command);
        this->SendPacket(p);
        return NETWORK_RECV_STATUS_OKAY;
}

/**
 * Tell that a client moved to another company.
 * @param client_id The client that moved.
 * @param company_id The company the client moved to.
 */
NetworkRecvStatus ServerNetworkGameSocketHandler::SendMove(ClientID client_id, CompanyID company_id)
{
        Packet *p = new Packet(PACKET_SERVER_MOVE);

        p->Send_uint32(client_id);
        p->Send_uint8(company_id);
        this->SendPacket(p);
        return NETWORK_RECV_STATUS_OKAY;
}

/** Send an update about the company password states. */
NetworkRecvStatus ServerNetworkGameSocketHandler::SendCompanyUpdate()
{
        Packet *p = new Packet(PACKET_SERVER_COMPANY_UPDATE);

        p->Send_uint16(_network_company_passworded);
        this->SendPacket(p);
        return NETWORK_RECV_STATUS_OKAY;
}

/** Send an update about the max company/spectator counts. */
NetworkRecvStatus ServerNetworkGameSocketHandler::SendConfigUpdate()
{
        Packet *p = new Packet(PACKET_SERVER_CONFIG_UPDATE);

        p->Send_uint8(_settings_client.network.max_companies);
        p->Send_uint8(_settings_client.network.max_spectators);
        this->SendPacket(p);
        return NETWORK_RECV_STATUS_OKAY;
}

/***********
 * Receiving functions
 *   DEF_SERVER_RECEIVE_COMMAND has parameter: NetworkClientSocket *cs, Packet *p
 ************/

NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_COMPANY_INFO(Packet *p)
{
        return this->SendCompanyInfo();
}

NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_NEWGRFS_CHECKED(Packet *p)
{
        if (this->status != STATUS_NEWGRFS_CHECK) {
                /* Illegal call, return error and ignore the packet */
                return this->SendError(NETWORK_ERROR_NOT_EXPECTED);
        }

        NetworkClientInfo *ci = this->GetInfo();

        /* We now want a password from the client else we do not allow him in! */
        if (!StrEmpty(_settings_client.network.server_password)) {
                return this->SendNeedGamePassword();
        }

        if (Company::IsValidID(ci->client_playas) && !StrEmpty(_network_company_states[ci->client_playas].password)) {
                return this->SendNeedCompanyPassword();
        }

        return this->SendWelcome();
}

NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_JOIN(Packet *p)
{
        if (this->status != STATUS_INACTIVE) {
                /* Illegal call, return error and ignore the packet */
                return this->SendError(NETWORK_ERROR_NOT_EXPECTED);
        }

        char name[NETWORK_CLIENT_NAME_LENGTH];
        CompanyID playas;
        NetworkLanguage client_lang;
        char client_revision[NETWORK_REVISION_LENGTH];

        p->Recv_string(client_revision, sizeof(client_revision));
        uint32 newgrf_version = p->Recv_uint32();

        /* Check if the client has revision control enabled */
        if (!IsNetworkCompatibleVersion(client_revision) || _openttd_newgrf_version != newgrf_version) {
                /* Different revisions!! */
                return this->SendError(NETWORK_ERROR_WRONG_REVISION);
        }

        p->Recv_string(name, sizeof(name));
        playas = (Owner)p->Recv_uint8();
        client_lang = (NetworkLanguage)p->Recv_uint8();

        if (this->HasClientQuit()) return NETWORK_RECV_STATUS_CONN_LOST;

        /* join another company does not affect these values */
        switch (playas) {
                case COMPANY_NEW_COMPANY: // New company
                        if (Company::GetNumItems() >= _settings_client.network.max_companies) {
                                return this->SendError(NETWORK_ERROR_FULL);
                        }
                        break;
                case COMPANY_SPECTATOR: // Spectator
                        if (NetworkSpectatorCount() >= _settings_client.network.max_spectators) {
                                return this->SendError(NETWORK_ERROR_FULL);
                        }
                        break;
                default: // Join another company (companies 1-8 (index 0-7))
                        if (!Company::IsValidHumanID(playas)) {
                                return this->SendError(NETWORK_ERROR_COMPANY_MISMATCH);
                        }
                        break;
        }

        /* We need a valid name.. make it Player */
        if (StrEmpty(name)) strecpy(name, "Player", lastof(name));

        if (!NetworkFindName(name, lastof(name))) { // Change name if duplicate
                /* We could not create a name for this client */
                return this->SendError(NETWORK_ERROR_NAME_IN_USE);
        }

        assert(NetworkClientInfo::CanAllocateItem());
        NetworkClientInfo *ci = new NetworkClientInfo(this->client_id);
        this->SetInfo(ci);
        ci->join_date = _date;
        strecpy(ci->client_name, name, lastof(ci->client_name));
        ci->client_playas = playas;
        ci->client_lang = client_lang;
        DEBUG(desync, 1, "client: %08x; %02x; %02x; %02x", _date, _date_fract, (int)ci->client_playas, (int)ci->index);

        /* Make sure companies to which people try to join are not autocleaned */
        if (Company::IsValidID(playas)) _network_company_states[playas].months_empty = 0;

        this->status = STATUS_NEWGRFS_CHECK;

        if (_grfconfig == nullptr) {
                /* Behave as if we received PACKET_CLIENT_NEWGRFS_CHECKED */
                return this->Receive_CLIENT_NEWGRFS_CHECKED(nullptr);
        }

        return this->SendNewGRFCheck();
}

NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_GAME_PASSWORD(Packet *p)
{
        if (this->status != STATUS_AUTH_GAME) {
                return this->SendError(NETWORK_ERROR_NOT_EXPECTED);
        }

        char password[NETWORK_PASSWORD_LENGTH];
        p->Recv_string(password, sizeof(password));

        /* Check game password. Allow joining if we cleared the password meanwhile */
        if (!StrEmpty(_settings_client.network.server_password) &&
                        strcmp(password, _settings_client.network.server_password) != 0) {
                /* Password is invalid */
                return this->SendError(NETWORK_ERROR_WRONG_PASSWORD);
        }

        const NetworkClientInfo *ci = this->GetInfo();
        if (Company::IsValidID(ci->client_playas) && !StrEmpty(_network_company_states[ci->client_playas].password)) {
                return this->SendNeedCompanyPassword();
        }

        /* Valid password, allow user */
        return this->SendWelcome();
}

NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_COMPANY_PASSWORD(Packet *p)
{
        if (this->status != STATUS_AUTH_COMPANY) {
                return this->SendError(NETWORK_ERROR_NOT_EXPECTED);
        }

        char password[NETWORK_PASSWORD_LENGTH];
        p->Recv_string(password, sizeof(password));

        /* Check company password. Allow joining if we cleared the password meanwhile.
         * Also, check the company is still valid - client could be moved to spectators
         * in the middle of the authorization process */
        CompanyID playas = this->GetInfo()->client_playas;
        if (Company::IsValidID(playas) && !StrEmpty(_network_company_states[playas].password) &&
                        strcmp(password, _network_company_states[playas].password) != 0) {
                /* Password is invalid */
                return this->SendError(NETWORK_ERROR_WRONG_PASSWORD);
        }

        return this->SendWelcome();
}

NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_GETMAP(Packet *p)
{
        /* The client was never joined.. so this is impossible, right?
         *  Ignore the packet, give the client a warning, and close his connection */
        if (this->status < STATUS_AUTHORIZED || this->HasClientQuit()) {
                return this->SendError(NETWORK_ERROR_NOT_AUTHORIZED);
        }

        /* Check if someone else is receiving the map */
        for (NetworkClientSocket *new_cs : NetworkClientSocket::Iterate()) {
                if (new_cs->status == STATUS_MAP) {
                        /* Tell the new client to wait */
                        this->status = STATUS_MAP_WAIT;
                        return this->SendWait();
                }
        }

        /* We receive a request to upload the map.. give it to the client! */
        return this->SendMap();
}

NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_MAP_OK(Packet *p)
{
        /* Client has the map, now start syncing */
        if (this->status == STATUS_DONE_MAP && !this->HasClientQuit()) {
                char client_name[NETWORK_CLIENT_NAME_LENGTH];

                this->GetClientName(client_name, lastof(client_name));

                NetworkTextMessage(NETWORK_ACTION_JOIN, CC_DEFAULT, false, client_name, nullptr, this->client_id);

                /* Mark the client as pre-active, and wait for an ACK
                 *  so we know he is done loading and in sync with us */
                this->status = STATUS_PRE_ACTIVE;
                NetworkHandleCommandQueue(this);
                this->SendFrame();
                this->SendSync();

                /* This is the frame the client receives
                 *  we need it later on to make sure the client is not too slow */
                this->last_frame = _frame_counter;
                this->last_frame_server = _frame_counter;

                for (NetworkClientSocket *new_cs : NetworkClientSocket::Iterate()) {
                        if (new_cs->status >= STATUS_AUTHORIZED) {
                                new_cs->SendClientInfo(this->GetInfo());
                                new_cs->SendJoin(this->client_id);
                        }
                }

                NetworkAdminClientInfo(this, true);

                /* also update the new client with our max values */
                this->SendConfigUpdate();

                /* quickly update the syncing client with company details */
                return this->SendCompanyUpdate();
        }

        /* Wrong status for this packet, give a warning to client, and close connection */
        return this->SendError(NETWORK_ERROR_NOT_EXPECTED);
}

/**
 * The client has done a command and wants us to handle it
 * @param p the packet in which the command was sent
 */
NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_COMMAND(Packet *p)
{
        /* The client was never joined.. so this is impossible, right?
         *  Ignore the packet, give the client a warning, and close his connection */
        if (this->status < STATUS_DONE_MAP || this->HasClientQuit()) {
                return this->SendError(NETWORK_ERROR_NOT_EXPECTED);
        }

        if (this->incoming_queue.Count() >= _settings_client.network.max_commands_in_queue) {
                return this->SendError(NETWORK_ERROR_TOO_MANY_COMMANDS);
        }

        CommandPacket cp;
        const char *err = this->ReceiveCommand(p, &cp);

        if (this->HasClientQuit()) return NETWORK_RECV_STATUS_CONN_LOST;

        NetworkClientInfo *ci = this->GetInfo();

        if (err != nullptr) {
                IConsolePrintF(CC_ERROR, "WARNING: %s from client %d (IP: %s).", err, ci->client_id, this->GetClientIP());
                return this->SendError(NETWORK_ERROR_NOT_EXPECTED);
        }


        if ((GetCommandFlags(cp.cmd) & CMD_SERVER) && ci->client_id != CLIENT_ID_SERVER) {
                IConsolePrintF(CC_ERROR, "WARNING: server only command %u from client %u (IP: %s), kicking...", cp.cmd & CMD_ID_MASK, ci->client_id, this->GetClientIP());
                return this->SendError(NETWORK_ERROR_KICKED);
        }

        if ((GetCommandFlags(cp.cmd) & CMD_SPECTATOR) == 0 && !Company::IsValidID(cp.company) && ci->client_id != CLIENT_ID_SERVER) {
                IConsolePrintF(CC_ERROR, "WARNING: spectator (client: %u, IP: %s) issued non-spectator command %u, kicking...", ci->client_id, this->GetClientIP(), cp.cmd & CMD_ID_MASK);
                return this->SendError(NETWORK_ERROR_KICKED);
        }

        /**
         * Only CMD_COMPANY_CTRL is always allowed, for the rest, playas needs
         * to match the company in the packet. If it doesn't, the client has done
         * something pretty naughty (or a bug), and will be kicked
         */
        if (!(cp.cmd == CMD_COMPANY_CTRL && cp.p1 == 0 && ci->client_playas == COMPANY_NEW_COMPANY) && ci->client_playas != cp.company) {
                IConsolePrintF(CC_ERROR, "WARNING: client %d (IP: %s) tried to execute a command as company %d, kicking...",
                               ci->client_playas + 1, this->GetClientIP(), cp.company + 1);
                return this->SendError(NETWORK_ERROR_COMPANY_MISMATCH);
        }

        if (cp.cmd == CMD_COMPANY_CTRL) {
                if (cp.p1 != 0 || cp.company != COMPANY_SPECTATOR) {
                        return this->SendError(NETWORK_ERROR_CHEATER);
                }

                /* Check if we are full - else it's possible for spectators to send a CMD_COMPANY_CTRL and the company is created regardless of max_companies! */
                if (Company::GetNumItems() >= _settings_client.network.max_companies) {
                        NetworkServerSendChat(NETWORK_ACTION_SERVER_MESSAGE, DESTTYPE_CLIENT, ci->client_id, "cannot create new company, server full", CLIENT_ID_SERVER);
                        return NETWORK_RECV_STATUS_OKAY;
                }
        }

        if (GetCommandFlags(cp.cmd) & CMD_CLIENT_ID) cp.p2 = this->client_id;

        this->incoming_queue.Append(&cp);
        return NETWORK_RECV_STATUS_OKAY;
}

NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_ERROR(Packet *p)
{
        /* This packets means a client noticed an error and is reporting this
         *  to us. Display the error and report it to the other clients */
        char str[100];
        char client_name[NETWORK_CLIENT_NAME_LENGTH];
        NetworkErrorCode errorno = (NetworkErrorCode)p->Recv_uint8();

        /* The client was never joined.. thank the client for the packet, but ignore it */
        if (this->status < STATUS_DONE_MAP || this->HasClientQuit()) {
                return this->CloseConnection(NETWORK_RECV_STATUS_CONN_LOST);
        }

        this->GetClientName(client_name, lastof(client_name));

        StringID strid = GetNetworkErrorMsg(errorno);
        GetString(str, strid, lastof(str));

        DEBUG(net, 2, "'%s' reported an error and is closing its connection (%s)", client_name, str);

        NetworkTextMessage(NETWORK_ACTION_LEAVE, CC_DEFAULT, false, client_name, nullptr, strid);

        for (NetworkClientSocket *new_cs : NetworkClientSocket::Iterate()) {
                if (new_cs->status >= STATUS_AUTHORIZED) {
                        new_cs->SendErrorQuit(this->client_id, errorno);
                }
        }

        NetworkAdminClientError(this->client_id, errorno);

        return this->CloseConnection(NETWORK_RECV_STATUS_CONN_LOST);
}

NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_QUIT(Packet *p)
{
        /* The client wants to leave. Display this and report it to the other
         *  clients. */
        char client_name[NETWORK_CLIENT_NAME_LENGTH];

        /* The client was never joined.. thank the client for the packet, but ignore it */
        if (this->status < STATUS_DONE_MAP || this->HasClientQuit()) {
                return this->CloseConnection(NETWORK_RECV_STATUS_CONN_LOST);
        }

        this->GetClientName(client_name, lastof(client_name));

        NetworkTextMessage(NETWORK_ACTION_LEAVE, CC_DEFAULT, false, client_name, nullptr, STR_NETWORK_MESSAGE_CLIENT_LEAVING);

        for (NetworkClientSocket *new_cs : NetworkClientSocket::Iterate()) {
                if (new_cs->status >= STATUS_AUTHORIZED && new_cs != this) {
                        new_cs->SendQuit(this->client_id);
                }
        }

        NetworkAdminClientQuit(this->client_id);

        return this->CloseConnection(NETWORK_RECV_STATUS_CONN_LOST);
}

NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_ACK(Packet *p)
{
        if (this->status < STATUS_AUTHORIZED) {
                /* Illegal call, return error and ignore the packet */
                return this->SendError(NETWORK_ERROR_NOT_AUTHORIZED);
        }

        uint32 frame = p->Recv_uint32();

        /* The client is trying to catch up with the server */
        if (this->status == STATUS_PRE_ACTIVE) {
                /* The client is not yet caught up? */
                if (frame + DAY_TICKS < _frame_counter) return NETWORK_RECV_STATUS_OKAY;

                /* Now he is! Unpause the game */
                this->status = STATUS_ACTIVE;
                this->last_token_frame = _frame_counter;

                /* Execute script for, e.g. MOTD */
                IConsoleCmdExec("exec scripts/on_server_connect.scr 0");
        }

        /* Get, and validate the token. */
        uint8 token = p->Recv_uint8();
        if (token == this->last_token) {
                /* We differentiate between last_token_frame and last_frame so the lag
                 * test uses the actual lag of the client instead of the lag for getting
                 * the token back and forth; after all, the token is only sent every
                 * time we receive a PACKET_CLIENT_ACK, after which we will send a new
                 * token to the client. If the lag would be one day, then we would not
                 * be sending the new token soon enough for the new daily scheduled
                 * PACKET_CLIENT_ACK. This would then register the lag of the client as
                 * two days, even when it's only a single day. */
                this->last_token_frame = _frame_counter;
                /* Request a new token. */
                this->last_token = 0;
        }

        /* The client received the frame, make note of it */
        this->last_frame = frame;
        /* With those 2 values we can calculate the lag realtime */
        this->last_frame_server = _frame_counter;
        return NETWORK_RECV_STATUS_OKAY;
}


/**
 * Send an actual chat message.
 * @param action The action that's performed.
 * @param desttype The type of destination.
 * @param dest The actual destination index.
 * @param msg The actual message.
 * @param from_id The origin of the message.
 * @param data Arbitrary data.
 * @param from_admin Whether the origin is an admin or not.
 */
void NetworkServerSendChat(NetworkAction action, DestType desttype, int dest, const char *msg, ClientID from_id, int64 data, bool from_admin)
{
        const NetworkClientInfo *ci, *ci_own, *ci_to;

        switch (desttype) {
                case DESTTYPE_CLIENT:
                        /* Are we sending to the server? */
                        if ((ClientID)dest == CLIENT_ID_SERVER) {
                                ci = NetworkClientInfo::GetByClientID(from_id);
                                /* Display the text locally, and that is it */
                                if (ci != nullptr) {
                                        NetworkTextMessage(action, GetDrawStringCompanyColour(ci->client_playas), false, ci->client_name, msg, data);

                                        if (_settings_client.network.server_admin_chat) {
                                                NetworkAdminChat(action, desttype, from_id, msg, data, from_admin);
                                        }
                                }
                        } else {
                                /* Else find the client to send the message to */
                                for (NetworkClientSocket *cs : NetworkClientSocket::Iterate()) {
                                        if (cs->client_id == (ClientID)dest) {
                                                cs->SendChat(action, from_id, false, msg, data);
                                                break;
                                        }
                                }
                        }

                        /* Display the message locally (so you know you have sent it) */
                        if (from_id != (ClientID)dest) {
                                if (from_id == CLIENT_ID_SERVER) {
                                        ci = NetworkClientInfo::GetByClientID(from_id);
                                        ci_to = NetworkClientInfo::GetByClientID((ClientID)dest);
                                        if (ci != nullptr && ci_to != nullptr) {
                                                NetworkTextMessage(action, GetDrawStringCompanyColour(ci->client_playas), true, ci_to->client_name, msg, data);
                                        }
                                } else {
                                        for (NetworkClientSocket *cs : NetworkClientSocket::Iterate()) {
                                                if (cs->client_id == from_id) {
                                                        cs->SendChat(action, (ClientID)dest, true, msg, data);
                                                        break;
                                                }
                                        }
                                }
                        }
                        break;
                case DESTTYPE_TEAM: {
                        /* If this is false, the message is already displayed on the client who sent it. */
                        bool show_local = true;
                        /* Find all clients that belong to this company */
                        ci_to = nullptr;
                        for (NetworkClientSocket *cs : NetworkClientSocket::Iterate()) {
                                ci = cs->GetInfo();
                                if (ci != nullptr && ci->client_playas == (CompanyID)dest) {
                                        cs->SendChat(action, from_id, false, msg, data);
                                        if (cs->client_id == from_id) show_local = false;
                                        ci_to = ci; // Remember a client that is in the company for company-name
                                }
                        }

                        /* if the server can read it, let the admin network read it, too. */
                        if (_local_company == (CompanyID)dest && _settings_client.network.server_admin_chat) {
                                NetworkAdminChat(action, desttype, from_id, msg, data, from_admin);
                        }

                        ci = NetworkClientInfo::GetByClientID(from_id);
                        ci_own = NetworkClientInfo::GetByClientID(CLIENT_ID_SERVER);
                        if (ci != nullptr && ci_own != nullptr && ci_own->client_playas == dest) {
                                NetworkTextMessage(action, GetDrawStringCompanyColour(ci->client_playas), false, ci->client_name, msg, data);
                                if (from_id == CLIENT_ID_SERVER) show_local = false;
                                ci_to = ci_own;
                        }

                        /* There is no such client */
                        if (ci_to == nullptr) break;

                        /* Display the message locally (so you know you have sent it) */
                        if (ci != nullptr && show_local) {
                                if (from_id == CLIENT_ID_SERVER) {
                                        char name[NETWORK_NAME_LENGTH];
                                        StringID str = Company::IsValidID(ci_to->client_playas) ? STR_COMPANY_NAME : STR_NETWORK_SPECTATORS;
                                        SetDParam(0, ci_to->client_playas);
                                        GetString(name, str, lastof(name));
                                        NetworkTextMessage(action, GetDrawStringCompanyColour(ci_own->client_playas), true, name, msg, data);
                                } else {
                                        for (NetworkClientSocket *cs : NetworkClientSocket::Iterate()) {
                                                if (cs->client_id == from_id) {
                                                        cs->SendChat(action, ci_to->client_id, true, msg, data);
                                                }
                                        }
                                }
                        }
                        break;
                }
                default:
                        DEBUG(net, 0, "[server] received unknown chat destination type %d. Doing broadcast instead", desttype);
                        FALLTHROUGH;

                case DESTTYPE_BROADCAST:
                        for (NetworkClientSocket *cs : NetworkClientSocket::Iterate()) {
                                cs->SendChat(action, from_id, false, msg, data);
                        }

                        NetworkAdminChat(action, desttype, from_id, msg, data, from_admin);

                        ci = NetworkClientInfo::GetByClientID(from_id);
                        if (ci != nullptr) {
                                NetworkTextMessage(action, GetDrawStringCompanyColour(ci->client_playas), false, ci->client_name, msg, data);
                        }
                        break;
        }
}

NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_CHAT(Packet *p)
{
        if (this->status < STATUS_PRE_ACTIVE) {
                /* Illegal call, return error and ignore the packet */
                return this->SendError(NETWORK_ERROR_NOT_AUTHORIZED);
        }

        NetworkAction action = (NetworkAction)p->Recv_uint8();
        DestType desttype = (DestType)p->Recv_uint8();
        int dest = p->Recv_uint32();
        char msg[NETWORK_CHAT_LENGTH];

        p->Recv_string(msg, NETWORK_CHAT_LENGTH);
        int64 data = p->Recv_uint64();

        NetworkClientInfo *ci = this->GetInfo();
        switch (action) {
                case NETWORK_ACTION_CHAT:
                case NETWORK_ACTION_CHAT_CLIENT:
                case NETWORK_ACTION_CHAT_COMPANY:
                        NetworkServerSendChat(action, desttype, dest, msg, this->client_id, data);
                        break;
                default:
                        IConsolePrintF(CC_ERROR, "WARNING: invalid chat action from client %d (IP: %s).", ci->client_id, this->GetClientIP());
                        return this->SendError(NETWORK_ERROR_NOT_EXPECTED);
        }
        return NETWORK_RECV_STATUS_OKAY;
}

NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_SET_PASSWORD(Packet *p)
{
        if (this->status != STATUS_ACTIVE) {
                /* Illegal call, return error and ignore the packet */
                return this->SendError(NETWORK_ERROR_NOT_EXPECTED);
        }

        char password[NETWORK_PASSWORD_LENGTH];
        const NetworkClientInfo *ci;

        p->Recv_string(password, sizeof(password));
        ci = this->GetInfo();

        NetworkServerSetCompanyPassword(ci->client_playas, password);
        return NETWORK_RECV_STATUS_OKAY;
}

NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_SET_NAME(Packet *p)
{
        if (this->status != STATUS_ACTIVE) {
                /* Illegal call, return error and ignore the packet */
                return this->SendError(NETWORK_ERROR_NOT_EXPECTED);
        }

        char client_name[NETWORK_CLIENT_NAME_LENGTH];
        NetworkClientInfo *ci;

        p->Recv_string(client_name, sizeof(client_name));
        ci = this->GetInfo();

        if (this->HasClientQuit()) return NETWORK_RECV_STATUS_CONN_LOST;

        if (ci != nullptr) {
                /* Display change */
                if (NetworkFindName(client_name, lastof(client_name))) {
                        NetworkTextMessage(NETWORK_ACTION_NAME_CHANGE, CC_DEFAULT, false, ci->client_name, client_name);
                        strecpy(ci->client_name, client_name, lastof(ci->client_name));
                        NetworkUpdateClientInfo(ci->client_id);
                }
        }
        return NETWORK_RECV_STATUS_OKAY;
}

NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_RCON(Packet *p)
{
        if (this->status != STATUS_ACTIVE) return this->SendError(NETWORK_ERROR_NOT_EXPECTED);

        char pass[NETWORK_PASSWORD_LENGTH];
        char command[NETWORK_RCONCOMMAND_LENGTH];

        if (StrEmpty(_settings_client.network.rcon_password)) return NETWORK_RECV_STATUS_OKAY;

        p->Recv_string(pass, sizeof(pass));
        p->Recv_string(command, sizeof(command));

        if (strcmp(pass, _settings_client.network.rcon_password) != 0) {
                DEBUG(net, 0, "[rcon] wrong password from client-id %d", this->client_id);
                return NETWORK_RECV_STATUS_OKAY;
        }

        DEBUG(net, 0, "[rcon] client-id %d executed: '%s'", this->client_id, command);

        _redirect_console_to_client = this->client_id;
        IConsoleCmdExec(command);
        _redirect_console_to_client = INVALID_CLIENT_ID;
        return NETWORK_RECV_STATUS_OKAY;
}

NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_MOVE(Packet *p)
{
        if (this->status != STATUS_ACTIVE) return this->SendError(NETWORK_ERROR_NOT_EXPECTED);

        CompanyID company_id = (Owner)p->Recv_uint8();

        /* Check if the company is valid, we don't allow moving to AI companies */
        if (company_id != COMPANY_SPECTATOR && !Company::IsValidHumanID(company_id)) return NETWORK_RECV_STATUS_OKAY;

        /* Check if we require a password for this company */
        if (company_id != COMPANY_SPECTATOR && !StrEmpty(_network_company_states[company_id].password)) {
                /* we need a password from the client - should be in this packet */
                char password[NETWORK_PASSWORD_LENGTH];
                p->Recv_string(password, sizeof(password));

                /* Incorrect password sent, return! */
                if (strcmp(password, _network_company_states[company_id].password) != 0) {
                        DEBUG(net, 2, "[move] wrong password from client-id #%d for company #%d", this->client_id, company_id + 1);
                        return NETWORK_RECV_STATUS_OKAY;
                }
        }

        /* if we get here we can move the client */
        NetworkServerDoMove(this->client_id, company_id);
        return NETWORK_RECV_STATUS_OKAY;
}

/**
 * Package some generic company information into a packet.
 * @param p       The packet that will contain the data.
 * @param c       The company to put the of into the packet.
 * @param stats   The statistics to put in the packet.
 * @param max_len The maximum length of the company name.
 */
void NetworkSocketHandler::SendCompanyInformation(Packet *p, const Company *c, const NetworkCompanyStats *stats, uint max_len)
{
        /* Grab the company name */
        char company_name[NETWORK_COMPANY_NAME_LENGTH];
        SetDParam(0, c->index);

        assert(max_len <= lengthof(company_name));
        GetString(company_name, STR_COMPANY_NAME, company_name + max_len - 1);

        /* Get the income */
        Money income = 0;
        if (_cur_year - 1 == c->inaugurated_year) {
                /* The company is here just 1 year, so display [2], else display[1] */
                for (uint i = 0; i < lengthof(c->yearly_expenses[2]); i++) {
                        income -= c->yearly_expenses[2][i];
                }
        } else {
                for (uint i = 0; i < lengthof(c->yearly_expenses[1]); i++) {
                        income -= c->yearly_expenses[1][i];
                }
        }

        /* Send the information */
        p->Send_uint8 (c->index);
        p->Send_string(company_name);
        p->Send_uint32(c->inaugurated_year);
        p->Send_uint64(c->old_economy[0].company_value);
        p->Send_uint64(c->money);
        p->Send_uint64(income);
        p->Send_uint16(c->old_economy[0].performance_history);

        /* Send 1 if there is a password for the company else send 0 */
        p->Send_bool  (!StrEmpty(_network_company_states[c->index].password));

        for (uint i = 0; i < NETWORK_VEH_END; i++) {
                p->Send_uint16(stats->num_vehicle[i]);
        }

        for (uint i = 0; i < NETWORK_VEH_END; i++) {
                p->Send_uint16(stats->num_station[i]);
        }

        p->Send_bool(c->is_ai);
}

/**
 * Populate the company stats.
 * @param stats the stats to update
 */
void NetworkPopulateCompanyStats(NetworkCompanyStats *stats)
{
        memset(stats, 0, sizeof(*stats) * MAX_COMPANIES);

        /* Go through all vehicles and count the type of vehicles */
        for (const Vehicle *v : Vehicle::Iterate()) {
                if (!Company::IsValidID(v->owner) || !v->IsPrimaryVehicle()) continue;
                byte type = 0;
                switch (v->type) {
                        case VEH_TRAIN: type = NETWORK_VEH_TRAIN; break;
                        case VEH_ROAD: type = RoadVehicle::From(v)->IsBus() ? NETWORK_VEH_BUS : NETWORK_VEH_LORRY; break;
                        case VEH_AIRCRAFT: type = NETWORK_VEH_PLANE; break;
                        case VEH_SHIP: type = NETWORK_VEH_SHIP; break;
                        default: continue;
                }
                stats[v->owner].num_vehicle[type]++;
        }

        /* Go through all stations and count the types of stations */
        for (const Station *s : Station::Iterate()) {
                if (Company::IsValidID(s->owner)) {
                        NetworkCompanyStats *npi = &stats[s->owner];

                        if (s->facilities & FACIL_TRAIN)      npi->num_station[NETWORK_VEH_TRAIN]++;
                        if (s->facilities & FACIL_TRUCK_STOP) npi->num_station[NETWORK_VEH_LORRY]++;
                        if (s->facilities & FACIL_BUS_STOP)   npi->num_station[NETWORK_VEH_BUS]++;
                        if (s->facilities & FACIL_AIRPORT)    npi->num_station[NETWORK_VEH_PLANE]++;
                        if (s->facilities & FACIL_DOCK)       npi->num_station[NETWORK_VEH_SHIP]++;
                }
        }
}

/**
 * Send updated client info of a particular client.
 * @param client_id The client to send it for.
 */
void NetworkUpdateClientInfo(ClientID client_id)
{
        NetworkClientInfo *ci = NetworkClientInfo::GetByClientID(client_id);

        if (ci == nullptr) return;

        DEBUG(desync, 1, "client: %08x; %02x; %02x; %04x", _date, _date_fract, (int)ci->client_playas, client_id);

        for (NetworkClientSocket *cs : NetworkClientSocket::Iterate()) {
                if (cs->status >= ServerNetworkGameSocketHandler::STATUS_AUTHORIZED) {
                        cs->SendClientInfo(ci);
                }
        }

        NetworkAdminClientUpdate(ci);
}

/** Check if we want to restart the map */
static void NetworkCheckRestartMap()
{
        if (_settings_client.network.restart_game_year != 0 && _cur_year >= _settings_client.network.restart_game_year) {
                DEBUG(net, 0, "Auto-restarting map. Year %d reached", _cur_year);

                _settings_newgame.game_creation.generation_seed = GENERATE_NEW_SEED;
                switch(_file_to_saveload.abstract_ftype) {
                        case FT_SAVEGAME:
                        case FT_SCENARIO:
                                _switch_mode = SM_LOAD_GAME;
                                break;

                        case FT_HEIGHTMAP:
                                _switch_mode = SM_START_HEIGHTMAP;
                                break;

                        default:
                                _switch_mode = SM_NEWGAME;
                }
        }
}

/** Check if the server has autoclean_companies activated
 * Two things happen:
 *     1) If a company is not protected, it is closed after 1 year (for example)
 *     2) If a company is protected, protection is disabled after 3 years (for example)
 *          (and item 1. happens a year later)
 */
static void NetworkAutoCleanCompanies()
{
        bool clients_in_company[MAX_COMPANIES];
        int vehicles_in_company[MAX_COMPANIES];

        if (!_settings_client.network.autoclean_companies) return;

        memset(clients_in_company, 0, sizeof(clients_in_company));

        /* Detect the active companies */
        for (const NetworkClientInfo *ci : NetworkClientInfo::Iterate()) {
                if (Company::IsValidID(ci->client_playas)) clients_in_company[ci->client_playas] = true;
        }

        if (!_network_dedicated) {
                const NetworkClientInfo *ci = NetworkClientInfo::GetByClientID(CLIENT_ID_SERVER);
                if (Company::IsValidID(ci->client_playas)) clients_in_company[ci->client_playas] = true;
        }

        if (_settings_client.network.autoclean_novehicles != 0) {
                memset(vehicles_in_company, 0, sizeof(vehicles_in_company));

                for (const Vehicle *v : Vehicle::Iterate()) {
                        if (!Company::IsValidID(v->owner) || !v->IsPrimaryVehicle()) continue;
                        vehicles_in_company[v->owner]++;
                }
        }

        /* Go through all the companies */
        for (const Company *c : Company::Iterate()) {
                /* Skip the non-active once */
                if (c->is_ai) continue;

                if (!clients_in_company[c->index]) {
                        /* The company is empty for one month more */
                        _network_company_states[c->index].months_empty++;

                        /* Is the company empty for autoclean_unprotected-months, and is there no protection? */
                        if (_settings_client.network.autoclean_unprotected != 0 && _network_company_states[c->index].months_empty > _settings_client.network.autoclean_unprotected && StrEmpty(_network_company_states[c->index].password)) {
                                /* Shut the company down */
                                DoCommandP(0, CCA_DELETE | c->index << 16 | CRR_AUTOCLEAN << 24, 0, CMD_COMPANY_CTRL);
                                IConsolePrintF(CC_DEFAULT, "Auto-cleaned company #%d with no password", c->index + 1);
                        }
                        /* Is the company empty for autoclean_protected-months, and there is a protection? */
                        if (_settings_client.network.autoclean_protected != 0 && _network_company_states[c->index].months_empty > _settings_client.network.autoclean_protected && !StrEmpty(_network_company_states[c->index].password)) {
                                /* Unprotect the company */
                                _network_company_states[c->index].password[0] = '\0';
                                IConsolePrintF(CC_DEFAULT, "Auto-removed protection from company #%d", c->index + 1);
                                _network_company_states[c->index].months_empty = 0;
                                NetworkServerUpdateCompanyPassworded(c->index, false);
                        }
                        /* Is the company empty for autoclean_novehicles-months, and has no vehicles? */
                        if (_settings_client.network.autoclean_novehicles != 0 && _network_company_states[c->index].months_empty > _settings_client.network.autoclean_novehicles && vehicles_in_company[c->index] == 0) {
                                /* Shut the company down */
                                DoCommandP(0, CCA_DELETE | c->index << 16 | CRR_AUTOCLEAN << 24, 0, CMD_COMPANY_CTRL);
                                IConsolePrintF(CC_DEFAULT, "Auto-cleaned company #%d with no vehicles", c->index + 1);
                        }
                } else {
                        /* It is not empty, reset the date */
                        _network_company_states[c->index].months_empty = 0;
                }
        }
}

/**
 * Check whether a name is unique, and otherwise try to make it unique.
 * @param new_name The name to check/modify.
 * @param last     The last writeable element of the buffer.
 * @return True if an unique name was achieved.
 */
bool NetworkFindName(char *new_name, const char *last)
{
        bool found_name = false;
        uint number = 0;
        char original_name[NETWORK_CLIENT_NAME_LENGTH];

        strecpy(original_name, new_name, lastof(original_name));

        while (!found_name) {
                found_name = true;
                for (const NetworkClientInfo *ci : NetworkClientInfo::Iterate()) {
                        if (strcmp(ci->client_name, new_name) == 0) {
                                /* Name already in use */
                                found_name = false;
                                break;
                        }
                }
                /* Check if it is the same as the server-name */
                const NetworkClientInfo *ci = NetworkClientInfo::GetByClientID(CLIENT_ID_SERVER);
                if (ci != nullptr) {
                        if (strcmp(ci->client_name, new_name) == 0) found_name = false; // name already in use
                }

                if (!found_name) {
                        /* Try a new name (<name> #1, <name> #2, and so on) */

                        /* Something's really wrong when there're more names than clients */
                        if (number++ > MAX_CLIENTS) break;
                        seprintf(new_name, last, "%s #%d", original_name, number);
                }
        }

        return found_name;
}

/**
 * Change the client name of the given client
 * @param client_id the client to change the name of
 * @param new_name the new name for the client
 * @return true iff the name was changed
 */
bool NetworkServerChangeClientName(ClientID client_id, const char *new_name)
{
        /* Check if the name's already in use */
        for (NetworkClientInfo *ci : NetworkClientInfo::Iterate()) {
                if (strcmp(ci->client_name, new_name) == 0) return false;
        }

        NetworkClientInfo *ci = NetworkClientInfo::GetByClientID(client_id);
        if (ci == nullptr) return false;

        NetworkTextMessage(NETWORK_ACTION_NAME_CHANGE, CC_DEFAULT, true, ci->client_name, new_name);

        strecpy(ci->client_name, new_name, lastof(ci->client_name));

        NetworkUpdateClientInfo(client_id);
        return true;
}

/**
 * Set/Reset a company password on the server end.
 * @param company_id ID of the company the password should be changed for.
 * @param password The new password.
 * @param already_hashed Is the given password already hashed?
 */
void NetworkServerSetCompanyPassword(CompanyID company_id, const char *password, bool already_hashed)
{
        if (!Company::IsValidHumanID(company_id)) return;

        if (!already_hashed) {
                password = GenerateCompanyPasswordHash(password, _settings_client.network.network_id, _settings_game.game_creation.generation_seed);
        }

        strecpy(_network_company_states[company_id].password, password, lastof(_network_company_states[company_id].password));
        NetworkServerUpdateCompanyPassworded(company_id, !StrEmpty(_network_company_states[company_id].password));
}

/**
 * Handle the command-queue of a socket.
 * @param cs The socket to handle the queue for.
 */
static void NetworkHandleCommandQueue(NetworkClientSocket *cs)
{
        CommandPacket *cp;
        while ((cp = cs->outgoing_queue.Pop()) != nullptr) {
                cs->SendCommand(cp);
                free(cp);
        }
}

/**
 * This is called every tick if this is a _network_server
 * @param send_frame Whether to send the frame to the clients.
 */
void NetworkServer_Tick(bool send_frame)
{
#ifndef ENABLE_NETWORK_SYNC_EVERY_FRAME
        bool send_sync = false;
#endif

#ifndef ENABLE_NETWORK_SYNC_EVERY_FRAME
        if (_frame_counter >= _last_sync_frame + _settings_client.network.sync_freq) {
                _last_sync_frame = _frame_counter;
                send_sync = true;
        }
#endif

        /* Now we are done with the frame, inform the clients that they can
         *  do their frame! */
        for (NetworkClientSocket *cs : NetworkClientSocket::Iterate()) {
                /* We allow a number of bytes per frame, but only to the burst amount
                 * to be available for packet receiving at any particular time. */
                cs->receive_limit = std::min<int>(cs->receive_limit + _settings_client.network.bytes_per_frame,
                                _settings_client.network.bytes_per_frame_burst);

                /* Check if the speed of the client is what we can expect from a client */
                uint lag = NetworkCalculateLag(cs);
                switch (cs->status) {
                        case NetworkClientSocket::STATUS_ACTIVE:
                                if (lag > _settings_client.network.max_lag_time) {
                                        /* Client did still not report in within the specified limit. */
                                        IConsolePrintF(CC_ERROR, cs->last_packet + std::chrono::milliseconds(lag * MILLISECONDS_PER_TICK) > std::chrono::steady_clock::now() ?
                                                        /* A packet was received in the last three game days, so the client is likely lagging behind. */
                                                                "Client #%d is dropped because the client's game state is more than %d ticks behind" :
                                                        /* No packet was received in the last three game days; sounds like a lost connection. */
                                                                "Client #%d is dropped because the client did not respond for more than %d ticks",
                                                        cs->client_id, lag);
                                        cs->SendError(NETWORK_ERROR_TIMEOUT_COMPUTER);
                                        continue;
                                }

                                /* Report once per time we detect the lag, and only when we
                                 * received a packet in the last 2 seconds. If we
                                 * did not receive a packet, then the client is not just
                                 * slow, but the connection is likely severed. Mentioning
                                 * frame_freq is not useful in this case. */
                                if (lag > (uint)DAY_TICKS && cs->lag_test == 0 && cs->last_packet + std::chrono::seconds(2) > std::chrono::steady_clock::now()) {
                                        IConsolePrintF(CC_WARNING, "[%d] Client #%d is slow, try increasing [network.]frame_freq to a higher value!", _frame_counter, cs->client_id);
                                        cs->lag_test = 1;
                                }

                                if (cs->last_frame_server - cs->last_token_frame >= _settings_client.network.max_lag_time) {
                                        /* This is a bad client! It didn't send the right token back within time. */
                                        IConsolePrintF(CC_ERROR, "Client #%d is dropped because it fails to send valid acks", cs->client_id);
                                        cs->SendError(NETWORK_ERROR_TIMEOUT_COMPUTER);
                                        continue;
                                }
                                break;

                        case NetworkClientSocket::STATUS_INACTIVE:
                        case NetworkClientSocket::STATUS_NEWGRFS_CHECK:
                        case NetworkClientSocket::STATUS_AUTHORIZED:
                                /* NewGRF check and authorized states should be handled almost instantly.
                                 * So give them some lee-way, likewise for the query with inactive. */
                                if (lag > _settings_client.network.max_init_time) {
                                        IConsolePrintF(CC_ERROR, "Client #%d is dropped because it took longer than %d ticks to start the joining process", cs->client_id, _settings_client.network.max_init_time);
                                        cs->SendError(NETWORK_ERROR_TIMEOUT_COMPUTER);
                                        continue;
                                }
                                break;

                        case NetworkClientSocket::STATUS_MAP_WAIT:
                                /* Send every two seconds a packet to the client, to make sure
                                 * he knows the server is still there; just someone else is
                                 * still receiving the map. */
                                if (std::chrono::steady_clock::now() > cs->last_packet + std::chrono::seconds(2)) {
                                        cs->SendWait();
                                        /* We need to reset the timer, as otherwise we will be
                                         * spamming the client. Strictly speaking this variable
                                         * tracks when we last received a packet from the client,
                                         * but as he is waiting, he will not send us any till we
                                         * start sending him data. */
                                        cs->last_packet = std::chrono::steady_clock::now();
                                }
                                break;

                        case NetworkClientSocket::STATUS_MAP:
                                /* Downloading the map... this is the amount of time since starting the saving. */
                                if (lag > _settings_client.network.max_download_time) {
                                        IConsolePrintF(CC_ERROR, "Client #%d is dropped because it took longer than %d ticks to download the map", cs->client_id, _settings_client.network.max_download_time);
                                        cs->SendError(NETWORK_ERROR_TIMEOUT_MAP);
                                        continue;
                                }
                                break;

                        case NetworkClientSocket::STATUS_DONE_MAP:
                        case NetworkClientSocket::STATUS_PRE_ACTIVE:
                                /* The map has been sent, so this is for loading the map and syncing up. */
                                if (lag > _settings_client.network.max_join_time) {
                                        IConsolePrintF(CC_ERROR, "Client #%d is dropped because it took longer than %d ticks to join", cs->client_id, _settings_client.network.max_join_time);
                                        cs->SendError(NETWORK_ERROR_TIMEOUT_JOIN);
                                        continue;
                                }
                                break;

                        case NetworkClientSocket::STATUS_AUTH_GAME:
                        case NetworkClientSocket::STATUS_AUTH_COMPANY:
                                /* These don't block? */
                                if (lag > _settings_client.network.max_password_time) {
                                        IConsolePrintF(CC_ERROR, "Client #%d is dropped because it took longer than %d ticks to enter the password", cs->client_id, _settings_client.network.max_password_time);
                                        cs->SendError(NETWORK_ERROR_TIMEOUT_PASSWORD);
                                        continue;
                                }
                                break;

                        case NetworkClientSocket::STATUS_END:
                                /* Bad server/code. */
                                NOT_REACHED();
                }

                if (cs->status >= NetworkClientSocket::STATUS_PRE_ACTIVE) {
                        /* Check if we can send command, and if we have anything in the queue */
                        NetworkHandleCommandQueue(cs);

                        /* Send an updated _frame_counter_max to the client */
                        if (send_frame) cs->SendFrame();

#ifndef ENABLE_NETWORK_SYNC_EVERY_FRAME
                        /* Send a sync-check packet */
                        if (send_sync) cs->SendSync();
#endif
                }
        }

        /* See if we need to advertise */
        NetworkUDPAdvertise();
}

/** Yearly "callback". Called whenever the year changes. */
void NetworkServerYearlyLoop()
{
        NetworkCheckRestartMap();
        NetworkAdminUpdate(ADMIN_FREQUENCY_ANUALLY);
}

/** Monthly "callback". Called whenever the month changes. */
void NetworkServerMonthlyLoop()
{
        NetworkAutoCleanCompanies();
        NetworkAdminUpdate(ADMIN_FREQUENCY_MONTHLY);
        if ((_cur_month % 3) == 0) NetworkAdminUpdate(ADMIN_FREQUENCY_QUARTERLY);
}

/** Daily "callback". Called whenever the date changes. */
void NetworkServerDailyLoop()
{
        NetworkAdminUpdate(ADMIN_FREQUENCY_DAILY);
        if ((_date % 7) == 3) NetworkAdminUpdate(ADMIN_FREQUENCY_WEEKLY);
}

/**
 * Get the IP address/hostname of the connected client.
 * @return The IP address.
 */
const char *ServerNetworkGameSocketHandler::GetClientIP()
{
        return this->client_address.GetHostname();
}

/** Show the status message of all clients on the console. */
void NetworkServerShowStatusToConsole()
{
        static const char * const stat_str[] = {
                "inactive",
                "checking NewGRFs",
                "authorizing (server password)",
                "authorizing (company password)",
                "authorized",
                "waiting",
                "loading map",
                "map done",
                "ready",
                "active"
        };
        static_assert(lengthof(stat_str) == NetworkClientSocket::STATUS_END);

        for (NetworkClientSocket *cs : NetworkClientSocket::Iterate()) {
                NetworkClientInfo *ci = cs->GetInfo();
                if (ci == nullptr) continue;
                uint lag = NetworkCalculateLag(cs);
                const char *status;

                status = (cs->status < (ptrdiff_t)lengthof(stat_str) ? stat_str[cs->status] : "unknown");
                IConsolePrintF(CC_INFO, "Client #%1d  name: '%s'  status: '%s'  frame-lag: %3d  company: %1d  IP: %s",
                        cs->client_id, ci->client_name, status, lag,
                        ci->client_playas + (Company::IsValidID(ci->client_playas) ? 1 : 0),
                        cs->GetClientIP());
        }
}

/**
 * Send Config Update
 */
void NetworkServerSendConfigUpdate()
{
        for (NetworkClientSocket *cs : NetworkClientSocket::Iterate()) {
                if (cs->status >= NetworkClientSocket::STATUS_PRE_ACTIVE) cs->SendConfigUpdate();
        }
}

/**
 * Tell that a particular company is (not) passworded.
 * @param company_id The company that got/removed the password.
 * @param passworded Whether the password was received or removed.
 */
void NetworkServerUpdateCompanyPassworded(CompanyID company_id, bool passworded)
{
        if (NetworkCompanyIsPassworded(company_id) == passworded) return;

        SB(_network_company_passworded, company_id, 1, !!passworded);
        SetWindowClassesDirty(WC_COMPANY);

        for (NetworkClientSocket *cs : NetworkClientSocket::Iterate()) {
                if (cs->status >= NetworkClientSocket::STATUS_PRE_ACTIVE) cs->SendCompanyUpdate();
        }

        NetworkAdminCompanyUpdate(Company::GetIfValid(company_id));
}

/**
 * Handle the tid-bits of moving a client from one company to another.
 * @param client_id id of the client we want to move.
 * @param company_id id of the company we want to move the client to.
 * @return void
 */
void NetworkServerDoMove(ClientID client_id, CompanyID company_id)
{
        /* Only allow non-dedicated servers and normal clients to be moved */
        if (client_id == CLIENT_ID_SERVER && _network_dedicated) return;

        NetworkClientInfo *ci = NetworkClientInfo::GetByClientID(client_id);

        /* No need to waste network resources if the client is in the company already! */
        if (ci->client_playas == company_id) return;

        ci->client_playas = company_id;

        if (client_id == CLIENT_ID_SERVER) {
                SetLocalCompany(company_id);
        } else {
                NetworkClientSocket *cs = NetworkClientSocket::GetByClientID(client_id);
                /* When the company isn't authorized we can't move them yet. */
                if (cs->status < NetworkClientSocket::STATUS_AUTHORIZED) return;
                cs->SendMove(client_id, company_id);
        }

        /* announce the client's move */
        NetworkUpdateClientInfo(client_id);

        NetworkAction action = (company_id == COMPANY_SPECTATOR) ? NETWORK_ACTION_COMPANY_SPECTATOR : NETWORK_ACTION_COMPANY_JOIN;
        NetworkServerSendChat(action, DESTTYPE_BROADCAST, 0, "", client_id, company_id + 1);
}

/**
 * Send an rcon reply to the client.
 * @param client_id The identifier of the client.
 * @param colour_code The colour of the text.
 * @param string The actual reply.
 */
void NetworkServerSendRcon(ClientID client_id, TextColour colour_code, const char *string)
{
        NetworkClientSocket::GetByClientID(client_id)->SendRConResult(colour_code, string);
}

/**
 * Kick a single client.
 * @param client_id The client to kick.
 * @param reason In case of kicking a client, specifies the reason for kicking the client.
 */
void NetworkServerKickClient(ClientID client_id, const char *reason)
{
        if (client_id == CLIENT_ID_SERVER) return;
        NetworkClientSocket::GetByClientID(client_id)->SendError(NETWORK_ERROR_KICKED, reason);
}

/**
 * Ban, or kick, everyone joined from the given client's IP.
 * @param client_id The client to check for.
 * @param ban Whether to ban or kick.
 * @param reason In case of kicking a client, specifies the reason for kicking the client.
 */
uint NetworkServerKickOrBanIP(ClientID client_id, bool ban, const char *reason)
{
        return NetworkServerKickOrBanIP(NetworkClientSocket::GetByClientID(client_id)->GetClientIP(), ban, reason);
}

/**
 * Kick or ban someone based on an IP address.
 * @param ip The IP address/range to ban/kick.
 * @param ban Whether to ban or just kick.
 * @param reason In case of kicking a client, specifies the reason for kicking the client.
 */
uint NetworkServerKickOrBanIP(const char *ip, bool ban, const char *reason)
{
        /* Add address to ban-list */
        if (ban) {
                bool contains = false;
                for (const auto &iter : _network_ban_list) {
                        if (iter == ip) {
                                contains = true;
                                break;
                        }
                }
                if (!contains) _network_ban_list.emplace_back(ip);
        }

        uint n = 0;

        /* There can be multiple clients with the same IP, kick them all but don't kill the server,
         * or the client doing the rcon. The latter can't be kicked because kicking frees closes
         * and subsequently free the connection related instances, which we would be reading from
         * and writing to after returning. So we would read or write data from freed memory up till
         * the segfault triggers. */
        for (NetworkClientSocket *cs : NetworkClientSocket::Iterate()) {
                if (cs->client_id == CLIENT_ID_SERVER) continue;
                if (cs->client_id == _redirect_console_to_client) continue;
                if (cs->client_address.IsInNetmask(ip)) {
                        NetworkServerKickClient(cs->client_id, reason);
                        n++;
                }
        }

        return n;
}

/**
 * Check whether a particular company has clients.
 * @param company The company to check.
 * @return True if at least one client is joined to the company.
 */
bool NetworkCompanyHasClients(CompanyID company)
{
        for (const NetworkClientInfo *ci : NetworkClientInfo::Iterate()) {
                if (ci->client_playas == company) return true;
        }
        return false;
}


/**
 * Get the name of the client, if the user did not send it yet, Client ID is used.
 * @param client_name The variable to write the name to.
 * @param last        The pointer to the last element of the destination buffer
 */
void ServerNetworkGameSocketHandler::GetClientName(char *client_name, const char *last) const
{
        const NetworkClientInfo *ci = this->GetInfo();

        if (ci == nullptr || StrEmpty(ci->client_name)) {
                seprintf(client_name, last, "Client #%4d", this->client_id);
        } else {
                strecpy(client_name, ci->client_name, last);
        }
}

/**
 * Print all the clients to the console
 */
void NetworkPrintClients()
{
        for (NetworkClientInfo *ci : NetworkClientInfo::Iterate()) {
                if (_network_server) {
                        IConsolePrintF(CC_INFO, "Client #%1d  name: '%s'  company: %1d  IP: %s",
                                        ci->client_id,
                                        ci->client_name,
                                        ci->client_playas + (Company::IsValidID(ci->client_playas) ? 1 : 0),
                                        ci->client_id == CLIENT_ID_SERVER ? "server" : NetworkClientSocket::GetByClientID(ci->client_id)->GetClientIP());
                } else {
                        IConsolePrintF(CC_INFO, "Client #%1d  name: '%s'  company: %1d",
                                        ci->client_id,
                                        ci->client_name,
                                        ci->client_playas + (Company::IsValidID(ci->client_playas) ? 1 : 0));
                }
        }
}

/**
 * Perform all the server specific administration of a new company.
 * @param c  The newly created company; can't be nullptr.
 * @param ci The client information of the client that made the company; can be nullptr.
 */
void NetworkServerNewCompany(const Company *c, NetworkClientInfo *ci)
{
        assert(c != nullptr);

        if (!_network_server) return;

        _network_company_states[c->index].months_empty = 0;
        _network_company_states[c->index].password[0] = '\0';
        NetworkServerUpdateCompanyPassworded(c->index, false);

        if (ci != nullptr) {
                /* ci is nullptr when replaying, or for AIs. In neither case there is a client. */
                ci->client_playas = c->index;
                NetworkUpdateClientInfo(ci->client_id);
                NetworkSendCommand(0, 0, 0, CMD_RENAME_PRESIDENT, nullptr, ci->client_name, c->index);
        }

        /* Announce new company on network. */
        NetworkAdminCompanyInfo(c, true);

        if (ci != nullptr) {
                /* ci is nullptr when replaying, or for AIs. In neither case there is a client.
                   We need to send Admin port update here so that they first know about the new company
                   and then learn about a possibly joining client (see FS#6025) */
                NetworkServerSendChat(NETWORK_ACTION_COMPANY_NEW, DESTTYPE_BROADCAST, 0, "", ci->client_id, c->index + 1);
        }
}