network_server.cpp

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/*
 * 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 <https://www.gnu.org/licenses/old-licenses/gpl-2.0>.
 */
 
#include "../stdafx.h"
#include "../strings_func.h"
#include "core/network_game_info.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 "../company_cmd.h"
#include "../roadveh.h"
#include "../order_backup.h"
#include "../core/pool_func.hpp"
#include "../core/random_func.hpp"
#include "../company_cmd.h"
#include "../rev.h"
#include "../timer/timer.h"
#include "../timer/timer_game_calendar.h"
#include "../timer/timer_game_economy.h"
#include "../timer/timer_game_realtime.h"
#include <mutex>
#include <condition_variable>
 
#include "table/strings.h"
 
#include "../safeguards.h"
 
 
/* This file handles all the server-commands */
 
DECLARE_INCREMENT_DECREMENT_OPERATORS(ClientID)
static ClientID _network_client_id = CLIENT_ID_FIRST;
 
static_assert(NetworkClientSocketPool::MAX_SIZE > MAX_CLIENTS);
 
NetworkClientSocketPool _networkclientsocket_pool("NetworkClientSocket");
INSTANTIATE_POOL_METHODS(NetworkClientSocket)
 
template SocketList TCPListenHandler<ServerNetworkGameSocketHandler, PACKET_SERVER_FULL, PACKET_SERVER_BANNED>::sockets;
 
static NetworkAuthenticationDefaultPasswordProvider _password_provider(_settings_client.network.server_password); 
static NetworkAuthenticationDefaultAuthorizedKeyHandler _authorized_key_handler(_settings_client.network.server_authorized_keys); 
static NetworkAuthenticationDefaultAuthorizedKeyHandler _rcon_authorized_key_handler(_settings_client.network.rcon_authorized_keys); 
 
 
struct PacketWriter : SaveFilter {
  ServerNetworkGameSocketHandler *cs; 
  std::unique_ptr<Packet> current; 
  size_t total_size;                  
  std::deque<std::unique_ptr<Packet>> packets; 
  std::mutex mutex;                   
  std::condition_variable exit_sig;   
 
  PacketWriter(ServerNetworkGameSocketHandler *cs) : SaveFilter(nullptr), cs(cs), total_size(0)
  {
  }
 
  ~PacketWriter() override
  {
    std::unique_lock<std::mutex> lock(this->mutex);
 
    while (this->cs != nullptr) this->exit_sig.wait(lock);
 
    /* This must all wait until the Destroy function is called. */
 
    this->packets.clear();
    this->current = nullptr;
  }
 
  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();
  }
 
  bool TransferToNetworkQueue()
  {
    /* Unsafe check for the queue being empty or not. */
    if (this->packets.empty()) return false;
 
    std::lock_guard<std::mutex> lock(this->mutex);
 
    while (!this->packets.empty()) {
      bool last_packet = this->packets.front()->GetPacketType() == PACKET_SERVER_MAP_DONE;
      this->cs->SendPacket(std::move(this->packets.front()));
      this->packets.pop_front();
 
      if (last_packet) return true;
    }
 
    return false;
  }
 
  void Write(uint8_t *buf, size_t size) override
  {
    std::lock_guard<std::mutex> lock(this->mutex);
 
    /* 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 = std::make_unique<Packet>(this->cs, PACKET_SERVER_MAP_DATA, TCP_MTU);
 
    std::span<const uint8_t> to_write(buf, size);
    while (!to_write.empty()) {
      to_write = this->current->Send_bytes(to_write);
 
      if (!this->current->CanWriteToPacket(1)) {
        this->packets.push_back(std::move(this->current));
        if (!to_write.empty()) this->current = std::make_unique<Packet>(this->cs, PACKET_SERVER_MAP_DATA, TCP_MTU);
      }
    }
 
    this->total_size += size;
  }
 
  void Finish() override
  {
    std::lock_guard<std::mutex> lock(this->mutex);
 
    /* We want to abort the saving when the socket is closed. */
    if (this->cs == nullptr) SlError(STR_NETWORK_ERROR_LOSTCONNECTION);
 
    /* Make sure the last packet is flushed. */
    if (this->current != nullptr) this->packets.push_back(std::move(this->current));
 
    /* Add a packet stating that this is the end to the queue. */
    this->packets.push_back(std::make_unique<Packet>(this->cs, PACKET_SERVER_MAP_DONE));
 
    /* Fast-track the size to the client. */
    auto p = std::make_unique<Packet>(this->cs, PACKET_SERVER_MAP_SIZE);
    p->Send_uint32((uint32_t)this->total_size);
    this->packets.push_front(std::move(p));
  }
};
 
 
ServerNetworkGameSocketHandler::ServerNetworkGameSocketHandler(ClientPoolID index, SOCKET s) :
  NetworkClientSocketPool::PoolItem<&_networkclientsocket_pool>(index), NetworkGameSocketHandler(s)
{
  this->client_id = _network_client_id++;
  this->receive_limit = _settings_client.network.bytes_per_frame_burst;
 
  Debug(net, 9, "client[{}] status = INACTIVE", this->client_id);
 
  /* 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);
}
 
ServerNetworkGameSocketHandler::~ServerNetworkGameSocketHandler()
{
  delete this->GetInfo();
 
  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;
  }
 
  InvalidateWindowData(WC_CLIENT_LIST, 0);
}
 
std::unique_ptr<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. */
  std::unique_ptr<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->IsPendingDeletion() || this->sock == INVALID_SOCKET) return status;
 
  if (status != NETWORK_RECV_STATUS_CLIENT_QUIT && status != NETWORK_RECV_STATUS_SERVER_ERROR && !this->HasClientQuit() && this->status >= STATUS_AUTHORIZED) {
    /* We did not receive a leave message from this client... */
    std::string client_name = this->GetClientName();
 
    NetworkTextMessage(NETWORK_ACTION_LEAVE, CC_DEFAULT, false, client_name, "", 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 transferring 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, 3, "[{}] Client #{} closed connection", ServerNetworkGameSocketHandler::GetName(), this->client_id);
 
  /* We just lost one client :( */
  if (this->status >= STATUS_AUTHORIZED) _network_game_info.clients_on--;
  extern uint8_t _network_clients_connected;
  _network_clients_connected--;
 
  this->SendPackets(true);
 
  this->DeferDeletion();
 
  return status;
}
 
/* static */ bool ServerNetworkGameSocketHandler::AllowConnection()
{
  extern uint8_t _network_clients_connected;
  bool accept = _network_clients_connected < 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;
}
 
/* 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
 ************/
 
NetworkRecvStatus ServerNetworkGameSocketHandler::SendClientInfo(NetworkClientInfo *ci)
{
  Debug(net, 9, "client[{}] SendClientInfo(): client_id={}", this->client_id, ci->client_id);
 
  if (ci->client_id != INVALID_CLIENT_ID) {
    auto p = std::make_unique<Packet>(this, PACKET_SERVER_CLIENT_INFO);
    p->Send_uint32(ci->client_id);
    p->Send_uint8 (ci->client_playas);
    p->Send_string(ci->client_name);
    p->Send_string(ci->public_key);
 
    this->SendPacket(std::move(p));
  }
  return NETWORK_RECV_STATUS_OKAY;
}
 
NetworkRecvStatus ServerNetworkGameSocketHandler::SendGameInfo()
{
  Debug(net, 9, "client[{}] SendGameInfo()", this->client_id);
 
  auto p = std::make_unique<Packet>(this, PACKET_SERVER_GAME_INFO, TCP_MTU);
  SerializeNetworkGameInfo(*p, GetCurrentNetworkServerGameInfo());
 
  this->SendPacket(std::move(p));
 
  return NETWORK_RECV_STATUS_OKAY;
}
 
NetworkRecvStatus ServerNetworkGameSocketHandler::SendError(NetworkErrorCode error, std::string_view reason)
{
  Debug(net, 9, "client[{}] SendError(): error={}", this->client_id, error);
 
  auto p = std::make_unique<Packet>(this, PACKET_SERVER_ERROR);
 
  p->Send_uint8(error);
  if (!reason.empty()) p->Send_string(reason);
  this->SendPacket(std::move(p));
 
  StringID strid = GetNetworkErrorMsg(error);
 
  /* Only send when the current client was in game */
  if (this->status >= STATUS_AUTHORIZED) {
    std::string client_name = this->GetClientName();
 
    Debug(net, 1, "'{}' made an error and has been disconnected: {}", client_name, GetString(strid));
 
    if (error == NETWORK_ERROR_KICKED && !reason.empty()) {
      NetworkTextMessage(NETWORK_ACTION_KICKED, CC_DEFAULT, false, client_name, reason, strid);
    } else {
      NetworkTextMessage(NETWORK_ACTION_LEAVE, CC_DEFAULT, false, client_name, "", 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 {} made an error and has been disconnected: {}", this->client_id, GetString(strid));
  }
 
  /* The client made a mistake, so drop the connection now! */
  return this->CloseConnection(NETWORK_RECV_STATUS_SERVER_ERROR);
}
 
NetworkRecvStatus ServerNetworkGameSocketHandler::SendNewGRFCheck()
{
  Debug(net, 9, "client[{}] SendNewGRFCheck()", this->client_id);
 
  /* Invalid packet when status is anything but STATUS_IDENTIFY. */
  if (this->status != STATUS_IDENTIFY) return this->CloseConnection(NETWORK_RECV_STATUS_MALFORMED_PACKET);
 
  Debug(net, 9, "client[{}] status = NEWGRFS_CHECK", this->client_id);
  this->status = STATUS_NEWGRFS_CHECK;
 
  if (_grfconfig.empty()) {
    /* There are no NewGRFs, so they're welcome. */
    return this->SendWelcome();
  }
 
  auto p = std::make_unique<Packet>(this, PACKET_SERVER_CHECK_NEWGRFS, TCP_MTU);
 
  uint grf_count = std::ranges::count_if(_grfconfig, [](const auto &c){ return !c->flags.Test(GRFConfigFlag::Static); });
  p->Send_uint8 (grf_count);
 
  for (const auto &c : _grfconfig) {
    if (!c->flags.Test(GRFConfigFlag::Static)) SerializeGRFIdentifier(*p, c->ident);
  }
 
  this->SendPacket(std::move(p));
  return NETWORK_RECV_STATUS_OKAY;
}
 
NetworkRecvStatus ServerNetworkGameSocketHandler::SendAuthRequest()
{
  Debug(net, 9, "client[{}] SendAuthRequest()", this->client_id);
 
  /* Invalid packet when status is anything but STATUS_INACTIVE or STATUS_AUTH_GAME. */
  if (this->status != STATUS_INACTIVE && status != STATUS_AUTH_GAME) return this->CloseConnection(NETWORK_RECV_STATUS_MALFORMED_PACKET);
 
  Debug(net, 9, "client[{}] status = AUTH_GAME", this->client_id);
  this->status = STATUS_AUTH_GAME;
 
  /* Reset 'lag' counters */
  this->last_frame = this->last_frame_server = _frame_counter;
 
  if (this->authentication_handler == nullptr) {
    this->authentication_handler = NetworkAuthenticationServerHandler::Create(&_password_provider, &_authorized_key_handler);
  }
 
  auto p = std::make_unique<Packet>(this, PACKET_SERVER_AUTH_REQUEST);
  this->authentication_handler->SendRequest(*p);
 
  this->SendPacket(std::move(p));
  return NETWORK_RECV_STATUS_OKAY;
}
 
NetworkRecvStatus ServerNetworkGameSocketHandler::SendEnableEncryption()
{
  Debug(net, 9, "client[{}] SendEnableEncryption()", this->client_id);
 
  /* Invalid packet when status is anything but STATUS_AUTH_GAME. */
  if (this->status != STATUS_AUTH_GAME) return this->CloseConnection(NETWORK_RECV_STATUS_MALFORMED_PACKET);
 
  auto p = std::make_unique<Packet>(this, PACKET_SERVER_ENABLE_ENCRYPTION);
  this->authentication_handler->SendEnableEncryption(*p);
  this->SendPacket(std::move(p));
  return NETWORK_RECV_STATUS_OKAY;
}
 
NetworkRecvStatus ServerNetworkGameSocketHandler::SendWelcome()
{
  Debug(net, 9, "client[{}] SendWelcome()", this->client_id);
 
  /* Invalid packet when status is anything but STATUS_NEWGRFS_CHECK. */
  if (this->status != STATUS_NEWGRFS_CHECK) return this->CloseConnection(NETWORK_RECV_STATUS_MALFORMED_PACKET);
 
  Debug(net, 9, "client[{}] status = AUTHORIZED", this->client_id);
  this->status = STATUS_AUTHORIZED;
 
  /* Reset 'lag' counters */
  this->last_frame = this->last_frame_server = _frame_counter;
 
  _network_game_info.clients_on++;
 
  auto p = std::make_unique<Packet>(this, PACKET_SERVER_WELCOME);
  p->Send_uint32(this->client_id);
  this->SendPacket(std::move(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));
}
 
NetworkRecvStatus ServerNetworkGameSocketHandler::SendWait()
{
  Debug(net, 9, "client[{}] SendWait()", this->client_id);
 
  int waiting = 1; // current player getting the map counts as 1
 
  /* 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++;
  }
 
  auto p = std::make_unique<Packet>(this, PACKET_SERVER_WAIT);
  p->Send_uint8(waiting);
  this->SendPacket(std::move(p));
  return NETWORK_RECV_STATUS_OKAY;
}
 
void ServerNetworkGameSocketHandler::CheckNextClientToSendMap(NetworkClientSocket *ignore_cs)
{
  Debug(net, 9, "client[{}] CheckNextClientToSendMap()", this->client_id);
 
  /* 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();
    }
  }
}
 
NetworkRecvStatus ServerNetworkGameSocketHandler::SendMap()
{
  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) {
    Debug(net, 9, "client[{}] SendMap(): first_packet", this->client_id);
 
    WaitTillSaved();
    this->savegame = std::make_shared<PacketWriter>(this);
 
    /* Now send the _frame_counter and how many packets are coming */
    auto p = std::make_unique<Packet>(this, PACKET_SERVER_MAP_BEGIN);
    p->Send_uint32(_frame_counter);
    this->SendPacket(std::move(p));
 
    NetworkSyncCommandQueue(this);
    Debug(net, 9, "client[{}] status = MAP", this->client_id);
    this->status = STATUS_MAP;
    /* Mark the start of download */
    this->last_frame = _frame_counter;
    this->last_frame_server = _frame_counter;
 
    /* 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 = this->savegame->TransferToNetworkQueue();
    if (last_packet) {
      Debug(net, 9, "client[{}] SendMap(): last_packet", this->client_id);
 
      /* 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 ;)) */
      Debug(net, 9, "client[{}] status = DONE_MAP", this->client_id);
      this->status = STATUS_DONE_MAP;
 
      this->CheckNextClientToSendMap();
    }
  }
  return NETWORK_RECV_STATUS_OKAY;
}
 
NetworkRecvStatus ServerNetworkGameSocketHandler::SendJoin(ClientID client_id)
{
  Debug(net, 9, "client[{}] SendJoin(): client_id={}", this->client_id, client_id);
 
  auto p = std::make_unique<Packet>(this, PACKET_SERVER_JOIN);
 
  p->Send_uint32(client_id);
 
  this->SendPacket(std::move(p));
  return NETWORK_RECV_STATUS_OKAY;
}
 
NetworkRecvStatus ServerNetworkGameSocketHandler::SendFrame()
{
  auto p = std::make_unique<Packet>(this, 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(std::move(p));
  return NETWORK_RECV_STATUS_OKAY;
}
 
NetworkRecvStatus ServerNetworkGameSocketHandler::SendSync()
{
  Debug(net, 9, "client[{}] SendSync(), frame_counter={}, sync_seed_1={}", this->client_id, _frame_counter, _sync_seed_1);
 
  auto p = std::make_unique<Packet>(this, 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(std::move(p));
  return NETWORK_RECV_STATUS_OKAY;
}
 
NetworkRecvStatus ServerNetworkGameSocketHandler::SendCommand(const CommandPacket &cp)
{
  Debug(net, 9, "client[{}] SendCommand(): cmd={}", this->client_id, cp.cmd);
 
  auto p = std::make_unique<Packet>(this, PACKET_SERVER_COMMAND);
 
  this->NetworkGameSocketHandler::SendCommand(*p, cp);
  p->Send_uint32(cp.frame);
  p->Send_bool  (cp.my_cmd);
 
  this->SendPacket(std::move(p));
  return NETWORK_RECV_STATUS_OKAY;
}
 
NetworkRecvStatus ServerNetworkGameSocketHandler::SendChat(NetworkAction action, ClientID client_id, bool self_send, std::string_view msg, int64_t data)
{
  Debug(net, 9, "client[{}] SendChat(): action={}, client_id={}, self_send={}", this->client_id, action, client_id, self_send);
 
  if (this->status < STATUS_PRE_ACTIVE) return NETWORK_RECV_STATUS_OKAY;
 
  auto p = std::make_unique<Packet>(this, 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(std::move(p));
  return NETWORK_RECV_STATUS_OKAY;
}
 
NetworkRecvStatus ServerNetworkGameSocketHandler::SendExternalChat(std::string_view source, TextColour colour, std::string_view user, std::string_view msg)
{
  Debug(net, 9, "client[{}] SendExternalChat(): source={}", this->client_id, source);
 
  if (this->status < STATUS_PRE_ACTIVE) return NETWORK_RECV_STATUS_OKAY;
 
  auto p = std::make_unique<Packet>(this, PACKET_SERVER_EXTERNAL_CHAT);
 
  p->Send_string(source);
  p->Send_uint16(colour);
  p->Send_string(user);
  p->Send_string(msg);
 
  this->SendPacket(std::move(p));
  return NETWORK_RECV_STATUS_OKAY;
}
 
NetworkRecvStatus ServerNetworkGameSocketHandler::SendErrorQuit(ClientID client_id, NetworkErrorCode errorno)
{
  Debug(net, 9, "client[{}] SendErrorQuit(): client_id={}, errorno={}", this->client_id, client_id, errorno);
 
  auto p = std::make_unique<Packet>(this, PACKET_SERVER_ERROR_QUIT);
 
  p->Send_uint32(client_id);
  p->Send_uint8 (errorno);
 
  this->SendPacket(std::move(p));
  return NETWORK_RECV_STATUS_OKAY;
}
 
NetworkRecvStatus ServerNetworkGameSocketHandler::SendQuit(ClientID client_id)
{
  Debug(net, 9, "client[{}] SendQuit(): client_id={}", this->client_id, client_id);
 
  auto p = std::make_unique<Packet>(this, PACKET_SERVER_QUIT);
 
  p->Send_uint32(client_id);
 
  this->SendPacket(std::move(p));
  return NETWORK_RECV_STATUS_OKAY;
}
 
NetworkRecvStatus ServerNetworkGameSocketHandler::SendShutdown()
{
  Debug(net, 9, "client[{}] SendShutdown()", this->client_id);
 
  auto p = std::make_unique<Packet>(this, PACKET_SERVER_SHUTDOWN);
  this->SendPacket(std::move(p));
  return NETWORK_RECV_STATUS_OKAY;
}
 
NetworkRecvStatus ServerNetworkGameSocketHandler::SendNewGame()
{
  Debug(net, 9, "client[{}] SendNewGame()", this->client_id);
 
  auto p = std::make_unique<Packet>(this, PACKET_SERVER_NEWGAME);
  this->SendPacket(std::move(p));
  return NETWORK_RECV_STATUS_OKAY;
}
 
NetworkRecvStatus ServerNetworkGameSocketHandler::SendRConResult(uint16_t colour, std::string_view command)
{
  Debug(net, 9, "client[{}] SendRConResult()", this->client_id);
 
  auto p = std::make_unique<Packet>(this, PACKET_SERVER_RCON);
 
  p->Send_uint16(colour);
  p->Send_string(command);
  this->SendPacket(std::move(p));
  return NETWORK_RECV_STATUS_OKAY;
}
 
NetworkRecvStatus ServerNetworkGameSocketHandler::SendMove(ClientID client_id, CompanyID company_id)
{
  Debug(net, 9, "client[{}] SendMove(): client_id={}", this->client_id, client_id);
 
  auto p = std::make_unique<Packet>(this, PACKET_SERVER_MOVE);
 
  p->Send_uint32(client_id);
  p->Send_uint8(company_id);
  this->SendPacket(std::move(p));
  return NETWORK_RECV_STATUS_OKAY;
}
 
NetworkRecvStatus ServerNetworkGameSocketHandler::SendConfigUpdate()
{
  Debug(net, 9, "client[{}] SendConfigUpdate()", this->client_id);
 
  auto p = std::make_unique<Packet>(this, PACKET_SERVER_CONFIG_UPDATE);
 
  p->Send_uint8(_settings_client.network.max_companies);
  p->Send_string(_settings_client.network.server_name);
  this->SendPacket(std::move(p));
  return NETWORK_RECV_STATUS_OKAY;
}
 
/***********
 * Receiving functions
 ************/
 
NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_GAME_INFO(Packet &)
{
  Debug(net, 9, "client[{}] Receive_CLIENT_GAME_INFO()", this->client_id);
 
  return this->SendGameInfo();
}
 
NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_NEWGRFS_CHECKED(Packet &)
{
  if (this->status != STATUS_NEWGRFS_CHECK) {
    /* Illegal call, return error and ignore the packet */
    return this->SendError(NETWORK_ERROR_NOT_EXPECTED);
  }
 
  Debug(net, 9, "client[{}] Receive_CLIENT_NEWGRFS_CHECKED()", this->client_id);
 
  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);
  }
 
  if (_network_game_info.clients_on >= _settings_client.network.max_clients) {
    /* Turns out we are full. Inform the user about this. */
    return this->SendError(NETWORK_ERROR_FULL);
  }
 
  std::string client_revision = p.Recv_string(NETWORK_REVISION_LENGTH);
  uint32_t newgrf_version = p.Recv_uint32();
 
  Debug(net, 9, "client[{}] Receive_CLIENT_JOIN(): client_revision={}, newgrf_version={}", this->client_id, client_revision, newgrf_version);
 
  /* 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);
  }
 
  return this->SendAuthRequest();
}
 
NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_IDENTIFY(Packet &p)
{
  if (this->status != STATUS_IDENTIFY) return this->SendError(NETWORK_ERROR_NOT_EXPECTED);
 
  Debug(net, 9, "client[{}] Receive_CLIENT_IDENTIFY()", this->client_id);
 
  std::string client_name = p.Recv_string(NETWORK_CLIENT_NAME_LENGTH);
  CompanyID playas = (Owner)p.Recv_uint8();
 
  if (this->HasClientQuit()) return NETWORK_RECV_STATUS_CLIENT_QUIT;
 
  /* join another company does not affect these values */
  switch (playas.base()) {
    case COMPANY_NEW_COMPANY.base(): // New company
      if (Company::GetNumItems() >= _settings_client.network.max_companies) {
        return this->SendError(NETWORK_ERROR_FULL);
      }
      break;
    case COMPANY_SPECTATOR.base(): // Spectator
      break;
    default: // Join another company (companies 1..MAX_COMPANIES (index 0..(MAX_COMPANIES-1)))
      if (!Company::IsValidHumanID(playas)) {
        return this->SendError(NETWORK_ERROR_COMPANY_MISMATCH);
      }
 
      if (!Company::Get(playas)->allow_list.Contains(this->peer_public_key)) {
        /* When we're not authorized, just bump us to a spectator. */
        playas = COMPANY_SPECTATOR;
      }
      break;
  }
 
  if (!NetworkIsValidClientName(client_name)) {
    /* An invalid client name was given. However, the client ensures the name
     * is valid before it is sent over the network, so something went horribly
     * wrong. This is probably someone trying to troll us. */
    return this->SendError(NETWORK_ERROR_INVALID_CLIENT_NAME);
  }
 
  if (!NetworkMakeClientNameUnique(client_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 = NetworkClientInfo::Create(this->client_id);
  this->SetInfo(ci);
  ci->join_date = TimerGameEconomy::date;
  ci->client_name = std::move(client_name);
  ci->client_playas = playas;
  ci->public_key = this->peer_public_key;
  Debug(desync, 1, "client: {:08x}; {:02x}; {:02x}; {:02x}", TimerGameEconomy::date, TimerGameEconomy::date_fract, ci->client_playas, ci->index);
 
  /* Make sure companies to which people try to join are not autocleaned */
  Company *c = Company::GetIfValid(playas);
  if (c != nullptr) c->months_empty = 0;
 
  return this->SendNewGRFCheck();
}
 
static NetworkErrorCode GetErrorForAuthenticationMethod(NetworkAuthenticationMethod method)
{
  switch (method) {
    case NetworkAuthenticationMethod::X25519_PAKE:
      return NETWORK_ERROR_WRONG_PASSWORD;
    case NetworkAuthenticationMethod::X25519_AuthorizedKey:
      return NETWORK_ERROR_NOT_ON_ALLOW_LIST;
 
    default:
      NOT_REACHED();
  }
}
 
NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_AUTH_RESPONSE(Packet &p)
{
  if (this->status != STATUS_AUTH_GAME) {
    return this->SendError(NETWORK_ERROR_NOT_EXPECTED);
  }
 
  Debug(net, 9, "client[{}] Receive_CLIENT_AUTH_RESPONSE()", this->client_id);
 
  auto authentication_method = this->authentication_handler->GetAuthenticationMethod();
  switch (this->authentication_handler->ReceiveResponse(p)) {
    case NetworkAuthenticationServerHandler::ResponseResult::Authenticated:
      break;
 
    case NetworkAuthenticationServerHandler::ResponseResult::RetryNextMethod:
      return this->SendAuthRequest();
 
    case NetworkAuthenticationServerHandler::ResponseResult::NotAuthenticated:
    default:
      return this->SendError(GetErrorForAuthenticationMethod(authentication_method));
  }
 
  NetworkRecvStatus status = this->SendEnableEncryption();
  if (status != NETWORK_RECV_STATUS_OKAY) return status;
 
  this->peer_public_key = this->authentication_handler->GetPeerPublicKey();
  this->receive_encryption_handler = this->authentication_handler->CreateClientToServerEncryptionHandler();
  this->send_encryption_handler = this->authentication_handler->CreateServerToClientEncryptionHandler();
  this->authentication_handler = nullptr;
 
  Debug(net, 9, "client[{}] status = IDENTIFY", this->client_id);
  this->status = STATUS_IDENTIFY;
 
  /* Reset 'lag' counters */
  this->last_frame = this->last_frame_server = _frame_counter;
 
  return NETWORK_RECV_STATUS_OKAY;
}
 
NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_GETMAP(Packet &)
{
  /* The client was never joined.. so this is impossible, right?
   *  Ignore the packet, give the client a warning, and close the connection */
  if (this->status < STATUS_AUTHORIZED || this->HasClientQuit()) {
    return this->SendError(NETWORK_ERROR_NOT_AUTHORIZED);
  }
 
  Debug(net, 9, "client[{}] Receive_CLIENT_GETMAP()", this->client_id);
 
  /* 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 */
      Debug(net, 9, "client[{}] status = MAP_WAIT", this->client_id);
      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 &)
{
  /* Client has the map, now start syncing */
  if (this->status == STATUS_DONE_MAP && !this->HasClientQuit()) {
    Debug(net, 9, "client[{}] Receive_CLIENT_MAP_OK()", this->client_id);
 
    std::string client_name = this->GetClientName();
 
    NetworkTextMessage(NETWORK_ACTION_JOIN, CC_DEFAULT, false, client_name, "", this->client_id);
    InvalidateWindowData(WC_CLIENT_LIST, 0);
 
    Debug(net, 3, "[{}] Client #{} ({}) joined as {}", ServerNetworkGameSocketHandler::GetName(), this->client_id, this->GetClientIP(), client_name);
 
    /* Mark the client as pre-active, and wait for an ACK
     *  so we know it is done loading and in sync with us */
    Debug(net, 9, "client[{}] status = PRE_ACTIVE", this->client_id);
    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 */
    return this->SendConfigUpdate();
  }
 
  /* Wrong status for this packet, give a warning to client, and close connection */
  return this->SendError(NETWORK_ERROR_NOT_EXPECTED);
}
 
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 the connection */
  if (this->status < STATUS_DONE_MAP || this->HasClientQuit()) {
    return this->SendError(NETWORK_ERROR_NOT_EXPECTED);
  }
 
  if (this->incoming_queue.size() >= _settings_client.network.max_commands_in_queue) {
    return this->SendError(NETWORK_ERROR_TOO_MANY_COMMANDS);
  }
 
  Debug(net, 9, "client[{}] Receive_CLIENT_COMMAND()", this->client_id);
 
  CommandPacket cp;
  auto err = this->ReceiveCommand(p, cp);
 
  if (this->HasClientQuit()) return NETWORK_RECV_STATUS_CLIENT_QUIT;
 
  NetworkClientInfo *ci = this->GetInfo();
 
  if (err.has_value()) {
    IConsolePrint(CC_WARNING, "Dropping client #{} (IP: {}) due to {}.", ci->client_id, this->GetClientIP(), *err);
    return this->SendError(NETWORK_ERROR_NOT_EXPECTED);
  }
 
  if (GetCommandFlags(cp.cmd).Test(CommandFlag::Server) && ci->client_id != CLIENT_ID_SERVER) {
    IConsolePrint(CC_WARNING, "Kicking client #{} (IP: {}) due to calling a server only command {}.", ci->client_id, this->GetClientIP(), cp.cmd);
    return this->SendError(NETWORK_ERROR_KICKED);
  }
 
  if (!GetCommandFlags(cp.cmd).Test(CommandFlag::Spectator) && !Company::IsValidID(cp.company) && ci->client_id != CLIENT_ID_SERVER) {
    IConsolePrint(CC_WARNING, "Kicking client #{} (IP: {}) due to calling a non-spectator command {}.", ci->client_id, this->GetClientIP(), cp.cmd);
    return this->SendError(NETWORK_ERROR_KICKED);
  }
 
  CompanyCtrlAction cca = cp.cmd == CMD_COMPANY_CTRL ? std::get<0>(EndianBufferReader::ToValue<CommandTraits<CMD_COMPANY_CTRL>::Args>(cp.data)) : CCA_NEW;
  if (!(cp.cmd == CMD_COMPANY_CTRL && cca == CCA_NEW && ci->client_playas == COMPANY_NEW_COMPANY) && ci->client_playas != cp.company) {
    IConsolePrint(CC_WARNING, "Kicking client #{} (IP: {}) due to calling a command as another company {}.",
                   ci->client_playas + 1, this->GetClientIP(), cp.company + 1);
    return this->SendError(NETWORK_ERROR_COMPANY_MISMATCH);
  }
 
  if (cp.cmd == CMD_COMPANY_CTRL) {
    if (cca != CCA_NEW || 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 (cp.cmd == CMD_COMPANY_ALLOW_LIST_CTRL) {
    /* Maybe the client just got moved before allowing? */
    if (ci->client_id != CLIENT_ID_SERVER && ci->client_playas != cp.company) return NETWORK_RECV_STATUS_OKAY;
 
    /* Only allow clients to add/remove currently joined clients. The server owner does not go via this method, so is allowed to do more. */
    std::string public_key = std::get<1>(EndianBufferReader::ToValue<CommandTraits<CMD_COMPANY_ALLOW_LIST_CTRL>::Args>(cp.data));
    bool found = false;
    for (const NetworkClientInfo *info : NetworkClientInfo::Iterate()) {
      if (info->public_key == public_key) {
        found = true;
        break;
      }
    }
 
    /* Maybe the client just left? */
    if (!found) return NETWORK_RECV_STATUS_OKAY;
  }
 
  if (GetCommandFlags(cp.cmd).Test(CommandFlag::ClientID)) NetworkReplaceCommandClientId(cp, this->client_id);
 
  this->incoming_queue.push_back(std::move(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 */
  NetworkErrorCode errorno = (NetworkErrorCode)p.Recv_uint8();
 
  Debug(net, 9, "client[{}] Receive_CLIENT_ERROR(): errorno={}", this->client_id, errorno);
 
  /* 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_CLIENT_QUIT);
  }
 
  std::string client_name = this->GetClientName();
  StringID strid = GetNetworkErrorMsg(errorno);
 
  Debug(net, 1, "'{}' reported an error and is closing its connection: {}", client_name, GetString(strid));
 
  NetworkTextMessage(NETWORK_ACTION_LEAVE, CC_DEFAULT, false, client_name, "", 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_CLIENT_QUIT);
}
 
NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_QUIT(Packet &)
{
  /* 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_CLIENT_QUIT);
  }
 
  Debug(net, 9, "client[{}] Receive_CLIENT_QUIT()", this->client_id);
 
  /* The client wants to leave. Display this and report it to the other clients. */
  std::string client_name = this->GetClientName();
  NetworkTextMessage(NETWORK_ACTION_LEAVE, CC_DEFAULT, false, client_name, "", 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_CLIENT_QUIT);
}
 
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_t frame = p.Recv_uint32();
 
  Debug(net, 9, "client[{}] Receive_CLIENT_ACK(): frame={}", this->client_id, frame);
 
  /* 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 + Ticks::DAY_TICKS < _frame_counter) return NETWORK_RECV_STATUS_OKAY;
 
    /* Now it is! Unpause the game */
    Debug(net, 9, "client[{}] status = ACTIVE", this->client_id);
    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_t 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;
}
 
 
void NetworkServerSendChat(NetworkAction action, DestType desttype, int dest, std::string_view msg, ClientID from_id, int64_t 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->status >= ServerNetworkGameSocketHandler::STATUS_AUTHORIZED) {
            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->status >= ServerNetworkGameSocketHandler::STATUS_AUTHORIZED) {
              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->status >= ServerNetworkGameSocketHandler::STATUS_AUTHORIZED) {
          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) {
          StringID str = Company::IsValidID(ci_to->client_playas) ? STR_COMPANY_NAME : STR_NETWORK_SPECTATORS;
          std::string name = GetString(str, ci_to->client_playas);
          NetworkTextMessage(action, GetDrawStringCompanyColour(ci_own->client_playas), true, name, msg, data);
        } else {
          for (NetworkClientSocket *cs : NetworkClientSocket::Iterate()) {
            if (cs->client_id == from_id && cs->status >= ServerNetworkGameSocketHandler::STATUS_AUTHORIZED) {
              cs->SendChat(action, ci_to->client_id, true, msg, data);
            }
          }
        }
      }
      break;
    }
    default:
      Debug(net, 1, "Received unknown chat destination type {}; doing broadcast instead", desttype);
      [[fallthrough]];
 
    case DESTTYPE_BROADCAST:
      for (NetworkClientSocket *cs : NetworkClientSocket::Iterate()) {
        if (cs->status >= ServerNetworkGameSocketHandler::STATUS_AUTHORIZED) 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;
  }
}
 
void NetworkServerSendExternalChat(std::string_view source, TextColour colour, std::string_view user, std::string_view msg)
{
  for (NetworkClientSocket *cs : NetworkClientSocket::Iterate()) {
    if (cs->status >= ServerNetworkGameSocketHandler::STATUS_AUTHORIZED) cs->SendExternalChat(source, colour, user, msg);
  }
  NetworkTextMessage(NETWORK_ACTION_EXTERNAL_CHAT, colour, false, user, msg, source);
}
 
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();
 
  Debug(net, 9, "client[{}] Receive_CLIENT_CHAT(): action={}, desttype={}, dest={}", this->client_id, action, desttype, dest);
 
  std::string msg = p.Recv_string(NETWORK_CHAT_LENGTH);
  int64_t 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:
      IConsolePrint(CC_WARNING, "Kicking client #{} (IP: {}) due to unknown chact action.", ci->client_id, this->GetClientIP());
      return this->SendError(NETWORK_ERROR_NOT_EXPECTED);
  }
  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);
  }
 
  Debug(net, 9, "client[{}] Receive_CLIENT_SET_NAME()", this->client_id);
 
  NetworkClientInfo *ci;
 
  std::string client_name = p.Recv_string(NETWORK_CLIENT_NAME_LENGTH);
  ci = this->GetInfo();
 
  if (this->HasClientQuit()) return NETWORK_RECV_STATUS_CLIENT_QUIT;
 
  if (ci != nullptr) {
    if (!NetworkIsValidClientName(client_name)) {
      /* An invalid client name was given. However, the client ensures the name
       * is valid before it is sent over the network, so something went horribly
       * wrong. This is probably someone trying to troll us. */
      return this->SendError(NETWORK_ERROR_INVALID_CLIENT_NAME);
    }
 
    /* Display change */
    if (NetworkMakeClientNameUnique(client_name)) {
      NetworkTextMessage(NETWORK_ACTION_NAME_CHANGE, CC_DEFAULT, false, ci->client_name, client_name);
      ci->client_name = std::move(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);
 
  Debug(net, 9, "client[{}] Receive_CLIENT_RCON()", this->client_id);
 
  std::string password = p.Recv_string(NETWORK_PASSWORD_LENGTH);
  std::string command = p.Recv_string(NETWORK_RCONCOMMAND_LENGTH);
 
  if (_rcon_authorized_key_handler.IsAllowed(this->peer_public_key)) {
    /* We are allowed, nothing more to validate. */
  } else if (_settings_client.network.rcon_password.empty()) {
    return NETWORK_RECV_STATUS_OKAY;
  } else if (_settings_client.network.rcon_password != password) {
    Debug(net, 1, "[rcon] Wrong password from client-id {}", this->client_id);
    return NETWORK_RECV_STATUS_OKAY;
  }
 
  Debug(net, 3, "[rcon] Client-id {} executed: {}", 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();
 
  Debug(net, 9, "client[{}] Receive_CLIENT_MOVE(): company_id={}", this->client_id, company_id);
 
  /* 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;
 
  if (company_id != COMPANY_SPECTATOR && !Company::Get(company_id)->allow_list.Contains(this->peer_public_key)) {
    Debug(net, 2, "Wrong public key from client-id #{} for company #{}", 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;
}
 
NetworkCompanyStatsArray NetworkGetCompanyStats()
{
  NetworkCompanyStatsArray stats = {};
 
  /* Go through all vehicles and count the type of vehicles */
  for (const Vehicle *v : Vehicle::Iterate()) {
    if (!Company::IsValidID(v->owner) || !v->IsPrimaryVehicle()) continue;
    uint8_t 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.Test(StationFacility::Train))     npi->num_station[NETWORK_VEH_TRAIN]++;
      if (s->facilities.Test(StationFacility::TruckStop)) npi->num_station[NETWORK_VEH_LORRY]++;
      if (s->facilities.Test(StationFacility::BusStop))   npi->num_station[NETWORK_VEH_BUS]++;
      if (s->facilities.Test(StationFacility::Airport))   npi->num_station[NETWORK_VEH_PLANE]++;
      if (s->facilities.Test(StationFacility::Dock))      npi->num_station[NETWORK_VEH_SHIP]++;
    }
  }
 
  return stats;
}
 
void NetworkUpdateClientInfo(ClientID client_id)
{
  NetworkClientInfo *ci = NetworkClientInfo::GetByClientID(client_id);
 
  if (ci == nullptr) return;
 
  Debug(desync, 1, "client: {:08x}; {:02x}; {:02x}; {:04x}", TimerGameEconomy::date, TimerGameEconomy::date_fract, ci->client_playas, client_id);
 
  for (NetworkClientSocket *cs : NetworkClientSocket::Iterate()) {
    if (cs->status >= ServerNetworkGameSocketHandler::STATUS_AUTHORIZED) {
      cs->SendClientInfo(ci);
    }
  }
 
  NetworkAdminClientUpdate(ci);
}
 
static void NetworkAutoCleanCompanies()
{
  CompanyMask has_clients{};
  CompanyMask has_vehicles{};
 
  if (!_settings_client.network.autoclean_companies) return;
 
  /* Detect the active companies */
  for (const NetworkClientInfo *ci : NetworkClientInfo::Iterate()) {
    if (Company::IsValidID(ci->client_playas)) has_clients.Set(ci->client_playas);
  }
 
  if (!_network_dedicated) {
    const NetworkClientInfo *ci = NetworkClientInfo::GetByClientID(CLIENT_ID_SERVER);
    assert(ci != nullptr);
    if (Company::IsValidID(ci->client_playas)) has_clients.Set(ci->client_playas);
  }
 
  if (_settings_client.network.autoclean_novehicles != 0) {
    for (const Company *c : Company::Iterate()) {
      if (std::any_of(std::begin(c->group_all), std::end(c->group_all), [](const GroupStatistics &gs) { return gs.num_vehicle != 0; })) has_vehicles.Set(c->index);
    }
  }
 
  /* Go through all the companies */
  for (Company *c : Company::Iterate()) {
    /* Skip the non-active once */
    if (c->is_ai) continue;
 
    if (!has_clients.Test(c->index)) {
      /* The company is empty for one month more */
      if (c->months_empty != std::numeric_limits<decltype(c->months_empty)>::max()) c->months_empty++;
 
      /* Is the company empty for autoclean_protected-months? */
      if (_settings_client.network.autoclean_protected != 0 && c->months_empty > _settings_client.network.autoclean_protected) {
        /* Shut the company down */
        Command<CMD_COMPANY_CTRL>::Post(CCA_DELETE, c->index, CRR_AUTOCLEAN, INVALID_CLIENT_ID);
        IConsolePrint(CC_INFO, "Auto-cleaned company #{}.", c->index + 1);
      }
      /* Is the company empty for autoclean_novehicles-months, and has no vehicles? */
      if (_settings_client.network.autoclean_novehicles != 0 && c->months_empty > _settings_client.network.autoclean_novehicles && !has_vehicles.Test(c->index)) {
        /* Shut the company down */
        Command<CMD_COMPANY_CTRL>::Post(CCA_DELETE, c->index, CRR_AUTOCLEAN, INVALID_CLIENT_ID);
        IConsolePrint(CC_INFO, "Auto-cleaned company #{} with no vehicles.", c->index + 1);
      }
    } else {
      /* It is not empty, reset the date */
      c->months_empty = 0;
    }
  }
}
 
bool NetworkMakeClientNameUnique(std::string &name)
{
  bool is_name_unique = false;
  std::string original_name = name;
 
  for (uint number = 1; !is_name_unique && number <= MAX_CLIENTS; number++) {  // Something's really wrong when there're more names than clients
    is_name_unique = true;
    for (const NetworkClientInfo *ci : NetworkClientInfo::Iterate()) {
      if (ci->client_name == name) {
        /* Name already in use */
        is_name_unique = false;
        break;
      }
    }
    /* Check if it is the same as the server-name */
    const NetworkClientInfo *ci = NetworkClientInfo::GetByClientID(CLIENT_ID_SERVER);
    if (ci != nullptr) {
      if (ci->client_name == name) is_name_unique = false; // name already in use
    }
 
    if (!is_name_unique) {
      /* Try a new name (<name> #1, <name> #2, and so on) */
      name = fmt::format("{} #{}", original_name, number);
 
      /* The constructed client name is larger than the limit,
       * so... bail out as no valid name can be created. */
      if (name.size() >= NETWORK_CLIENT_NAME_LENGTH) return false;
    }
  }
 
  return is_name_unique;
}
 
bool NetworkServerChangeClientName(ClientID client_id, const std::string &new_name)
{
  /* Check if the name's already in use */
  for (NetworkClientInfo *ci : NetworkClientInfo::Iterate()) {
    if (ci->client_name == new_name) 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);
 
  ci->client_name = new_name;
 
  NetworkUpdateClientInfo(client_id);
  return true;
}
 
static void NetworkHandleCommandQueue(NetworkClientSocket *cs)
{
  for (auto &cp : cs->outgoing_queue) cs->SendCommand(cp);
  cs->outgoing_queue.clear();
}
 
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<size_t>(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. */
 
          if (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. */
            IConsolePrint(CC_WARNING, "Client #{} (IP: {}) is dropped because the client's game state is more than {} ticks behind.", cs->client_id, cs->GetClientIP(), lag);
          } else {
            /* No packet was received in the last three game days; sounds like a lost connection. */
            IConsolePrint(CC_WARNING, "Client #{} (IP: {}) is dropped because the client did not respond for more than {} ticks.", cs->client_id, cs->GetClientIP(), 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)Ticks::DAY_TICKS && cs->lag_test == 0 && cs->last_packet + std::chrono::seconds(2) > std::chrono::steady_clock::now()) {
          IConsolePrint(CC_WARNING, "[{}] Client #{} 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. */
          IConsolePrint(CC_WARNING, "Client #{} (IP: {}) is dropped because it fails to send valid acks.", cs->client_id, cs->GetClientIP());
          cs->SendError(NETWORK_ERROR_TIMEOUT_COMPUTER);
          continue;
        }
        break;
 
      case NetworkClientSocket::STATUS_INACTIVE:
      case NetworkClientSocket::STATUS_IDENTIFY:
      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) {
          IConsolePrint(CC_WARNING, "Client #{} (IP: {}) is dropped because it took longer than {} ticks to start the joining process.", cs->client_id, cs->GetClientIP(), _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
         * it 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 it is waiting, it will not send us any till we
           * start sending them 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) {
          IConsolePrint(CC_WARNING, "Client #{} (IP: {}) is dropped because it took longer than {} ticks to download the map.", cs->client_id, cs->GetClientIP(), _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) {
          IConsolePrint(CC_WARNING, "Client #{} (IP: {}) is dropped because it took longer than {} ticks to join.", cs->client_id, cs->GetClientIP(), _settings_client.network.max_join_time);
          cs->SendError(NETWORK_ERROR_TIMEOUT_JOIN);
          continue;
        }
        break;
 
      case NetworkClientSocket::STATUS_AUTH_GAME:
        /* These don't block? */
        if (lag > _settings_client.network.max_password_time) {
          IConsolePrint(CC_WARNING, "Client #{} (IP: {}) is dropped because it took longer than {} ticks to enter the password.", cs->client_id, cs->GetClientIP(), _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
    }
  }
}
 
static void NetworkRestartMap()
{
  _settings_newgame.game_creation.generation_seed = GENERATE_NEW_SEED;
  switch (_file_to_saveload.ftype.abstract) {
    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;
  }
}
 
static IntervalTimer<TimerGameRealtime> _network_restart_map_timer({std::chrono::hours::zero(), TimerGameRealtime::UNPAUSED}, [](auto)
{
  if (!_network_server) return;
 
  /* If setting is 0, this feature is disabled. */
  if (_settings_client.network.restart_hours == 0) return;
 
  Debug(net, 3, "Auto-restarting map: {} hours played", _settings_client.network.restart_hours);
  NetworkRestartMap();
});
 
void ChangeNetworkRestartTime(bool reset)
{
  if (!_network_server) return;
 
  _network_restart_map_timer.SetInterval({ std::chrono::hours(_settings_client.network.restart_hours), TimerGameRealtime::UNPAUSED }, reset);
}
 
static void NetworkCheckRestartMapYear()
{
  /* If setting is 0, this feature is disabled. */
  if (_settings_client.network.restart_game_year == 0) return;
 
  if (TimerGameCalendar::year >= _settings_client.network.restart_game_year) {
    Debug(net, 3, "Auto-restarting map: year {} reached", TimerGameCalendar::year);
    NetworkRestartMap();
  }
}
 
static const IntervalTimer<TimerGameCalendar> _calendar_network_yearly({ TimerGameCalendar::YEAR, TimerGameCalendar::Priority::NONE }, [](auto) {
  if (!_network_server) return;
 
  NetworkCheckRestartMapYear();
});
 
static const IntervalTimer<TimerGameEconomy> _economy_network_yearly({TimerGameEconomy::YEAR, TimerGameEconomy::Priority::NONE}, [](auto)
{
  if (!_network_server) return;
 
  NetworkAdminUpdate(AdminUpdateFrequency::Annually);
});
 
static const IntervalTimer<TimerGameEconomy> _network_quarterly({TimerGameEconomy::QUARTER, TimerGameEconomy::Priority::NONE}, [](auto)
{
  if (!_network_server) return;
 
  NetworkAutoCleanCompanies();
  NetworkAdminUpdate(AdminUpdateFrequency::Quarterly);
});
 
static const IntervalTimer<TimerGameEconomy> _network_monthly({TimerGameEconomy::MONTH, TimerGameEconomy::Priority::NONE}, [](auto)
{
  if (!_network_server) return;
 
  NetworkAutoCleanCompanies();
  NetworkAdminUpdate(AdminUpdateFrequency::Monthly);
});
 
static const IntervalTimer<TimerGameEconomy> _network_weekly({TimerGameEconomy::WEEK, TimerGameEconomy::Priority::NONE}, [](auto)
{
  if (!_network_server) return;
 
  NetworkAdminUpdate(AdminUpdateFrequency::Weekly);
});
 
static const IntervalTimer<TimerGameEconomy> _economy_network_daily({TimerGameEconomy::DAY, TimerGameEconomy::Priority::NONE}, [](auto)
{
  if (!_network_server) return;
 
  NetworkAdminUpdate(AdminUpdateFrequency::Daily);
});
 
std::string_view ServerNetworkGameSocketHandler::GetClientIP()
{
  return this->client_address.GetHostname();
}
 
void NetworkServerShowStatusToConsole()
{
  static const std::string_view stat_str[] = {
    "inactive",
    "authorizing",
    "identifying client",
    "checking NewGRFs",
    "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);
 
    std::string_view status = (cs->status < (ptrdiff_t)lengthof(stat_str) ? stat_str[cs->status] : "unknown");
    IConsolePrint(CC_INFO, "Client #{}  name: '{}'  status: '{}'  frame-lag: {}  company: {}  IP: {}",
      cs->client_id, ci->client_name, status, lag,
      ci->client_playas + (Company::IsValidID(ci->client_playas) ? 1 : 0),
      cs->GetClientIP());
  }
}
 
void NetworkServerSendConfigUpdate()
{
  for (NetworkClientSocket *cs : NetworkClientSocket::Iterate()) {
    if (cs->status >= NetworkClientSocket::STATUS_PRE_ACTIVE) cs->SendConfigUpdate();
  }
}
 
void NetworkServerUpdateGameInfo()
{
  if (_network_server) FillStaticNetworkServerGameInfo();
}
 
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);
  assert(ci != nullptr);
 
  /* 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);
 
  if (company_id == COMPANY_SPECTATOR) {
    /* The client has joined spectators. */
    NetworkServerSendChat(NETWORK_ACTION_COMPANY_SPECTATOR, DESTTYPE_BROADCAST, 0, "", client_id);
  } else {
    /* The client has joined another company. */
    std::string company_name = GetString(STR_COMPANY_NAME, company_id);
    NetworkServerSendChat(NETWORK_ACTION_COMPANY_JOIN, DESTTYPE_BROADCAST, 0, company_name, client_id);
  }
 
  InvalidateWindowData(WC_CLIENT_LIST, 0);
}
 
void NetworkServerSendRcon(ClientID client_id, TextColour colour_code, std::string_view string)
{
  NetworkClientSocket::GetByClientID(client_id)->SendRConResult(colour_code, string);
}
 
void NetworkServerKickClient(ClientID client_id, std::string_view reason)
{
  if (client_id == CLIENT_ID_SERVER) return;
  NetworkClientSocket::GetByClientID(client_id)->SendError(NETWORK_ERROR_KICKED, reason);
}
 
uint NetworkServerKickOrBanIP(ClientID client_id, bool ban, std::string_view reason)
{
  return NetworkServerKickOrBanIP(NetworkClientSocket::GetByClientID(client_id)->GetClientIP(), ban, reason);
}
 
uint NetworkServerKickOrBanIP(std::string_view ip, bool ban, std::string_view 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;
}
 
bool NetworkCompanyHasClients(CompanyID company)
{
  for (const NetworkClientInfo *ci : NetworkClientInfo::Iterate()) {
    if (ci->client_playas == company) return true;
  }
  return false;
}
 
 
std::string ServerNetworkGameSocketHandler::GetClientName() const
{
  const NetworkClientInfo *ci = this->GetInfo();
  if (ci != nullptr && !ci->client_name.empty()) return ci->client_name;
 
  return fmt::format("Client #{}", this->client_id);
}
 
void NetworkPrintClients()
{
  for (NetworkClientInfo *ci : NetworkClientInfo::Iterate()) {
    if (_network_server) {
      IConsolePrint(CC_INFO, "Client #{}  name: '{}'  company: {}  IP: {}",
          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 {
      IConsolePrint(CC_INFO, "Client #{}  name: '{}'  company: {}",
          ci->client_id,
          ci->client_name,
          ci->client_playas + (Company::IsValidID(ci->client_playas) ? 1 : 0));
    }
  }
}
 
std::string_view NetworkGetPublicKeyOfClient(ClientID client_id)
{
  auto socket = NetworkClientSocket::GetByClientID(client_id);
  return socket == nullptr ? "" : socket->GetPeerPublicKey();
}
 
 
void NetworkServerNewCompany(const Company *c, NetworkClientInfo *ci)
{
  assert(c != nullptr);
 
  if (!_network_server) return;
 
  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);
 
    /*
     * This function is called from a command, but is only called for the server.
     * The client information is managed out-of-band from the commands, so to not have a
     * different state/president/company name in the different clients, we need to
     * circumvent the normal ::Post logic and go directly to sending the command.
     */
    Command<CMD_COMPANY_ALLOW_LIST_CTRL>::SendNet(STR_NULL, c->index, CALCA_ADD, ci->public_key);
    Command<CMD_RENAME_PRESIDENT>::SendNet(STR_NULL, c->index, ci->client_name);
 
    NetworkServerSendChat(NETWORK_ACTION_COMPANY_NEW, DESTTYPE_BROADCAST, 0, "", ci->client_id, c->index + 1);
  }
}