network_game_info.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 "network_game_info.h"
#include "../../company_base.h"
#include "../../timer/timer_game_calendar.h"
#include "../../timer/timer_game_tick.h"
#include "../../debug.h"
#include "../../map_func.h"
#include "../../game/game.hpp"
#include "../../game/game_info.hpp"
#include "../../settings_type.h"
#include "../../string_func.h"
#include "../../rev.h"
#include "../network_func.h"
#include "../network.h"
#include "../network_internal.h"
#include "packet.h"
 
#include "table/strings.h"
 
#include "../../safeguards.h"
 

static const uint GITHASH_SUFFIX_LEN = 12;
 
NetworkServerGameInfo _network_game_info; 

std::string_view GetNetworkRevisionString()
{
  static std::string network_revision;
 
  if (network_revision.empty()) {
#if not defined(NETWORK_INTERNAL_H)
# error("network_internal.h must be included, otherwise the debug related preprocessor tokens won't be picked up correctly.")
#elif not defined(ENABLE_NETWORK_SYNC_EVERY_FRAME)
    /* Just a standard build. */
    network_revision = _openttd_revision;
#elif defined(NETWORK_SEND_DOUBLE_SEED)
    /* Build for debugging that sends both parts of the seeds and by doing that practically syncs every frame. */
    network_revision = fmt::format("dbg_seed-{}", _openttd_revision);
#else
    /* Build for debugging that sends the first part of the seed every frame, practically syncing every frame. */
    network_revision = fmt::format("dbg_sync-{}", _openttd_revision);
#endif
    if (_openttd_revision_tagged) {
      /* Tagged; do not mangle further, though ensure it's not too long. */
      if (network_revision.size() >= NETWORK_REVISION_LENGTH) network_revision.resize(NETWORK_REVISION_LENGTH - 1);
    } else {
      /* Not tagged; add the githash suffix while ensuring the string does not become too long. */
      assert(_openttd_revision_modified < 3);
      std::string githash_suffix = fmt::format("-{}{}", "gum"[_openttd_revision_modified], _openttd_revision_hash);
      if (githash_suffix.size() > GITHASH_SUFFIX_LEN) githash_suffix.resize(GITHASH_SUFFIX_LEN);
 
      /* Where did the hash start in the original string? Overwrite from that position, unless that would create a too long string. */
      size_t hash_end = network_revision.find_last_of('-');
      if (hash_end == std::string::npos) hash_end = network_revision.size();
      if (hash_end + githash_suffix.size() >= NETWORK_REVISION_LENGTH) hash_end = NETWORK_REVISION_LENGTH - githash_suffix.size() - 1;
 
      /* Replace the git hash in revision string. */
      network_revision.replace(hash_end, std::string::npos, githash_suffix);
    }
    assert(network_revision.size() < NETWORK_REVISION_LENGTH); // size does not include terminator, constant does, hence strictly less than
    Debug(net, 3, "Network revision name: {}", network_revision);
  }
 
  return network_revision;
}

static std::string_view ExtractNetworkRevisionHash(std::string_view revision_string)
{
  size_t index = revision_string.find_last_of('-');
  if (index == std::string::npos) return {};
  return revision_string.substr(index);
}

bool IsNetworkCompatibleVersion(std::string_view other)
{
  std::string_view our_revision = GetNetworkRevisionString();
  if (our_revision == other) return true;
 
  /* If this version is tagged, then the revision string must be a complete match,
   * since there is no git hash suffix in it.
   * This is needed to avoid situations like "1.9.0-beta1" comparing equal to "2.0.0-beta1".  */
  if (_openttd_revision_tagged) return false;
 
  /* One of the versions is for some sort of debugging, but not both. */
  if (other.starts_with("dbg_seed") != our_revision.starts_with("dbg_seed")) return false;
  if (other.starts_with("dbg_sync") != our_revision.starts_with("dbg_sync")) return false;
 
  std::string_view hash1 = ExtractNetworkRevisionHash(our_revision);
  std::string_view hash2 = ExtractNetworkRevisionHash(other);
  return hash1 == hash2;
}

void CheckGameCompatibility(NetworkGameInfo &ngi)
{
  /* Check if we are allowed on this server based on the revision-check. */
  ngi.version_compatible = IsNetworkCompatibleVersion(ngi.server_revision);
  ngi.compatible = ngi.version_compatible;
 
  /* Check if we have all the GRFs on the client-system too. */
  for (const auto &c : ngi.grfconfig) {
    if (c->status == GCS_NOT_FOUND) ngi.compatible = false;
  }
}

void FillStaticNetworkServerGameInfo()
{
  _network_game_info.use_password   = !_settings_client.network.server_password.empty();
  _network_game_info.calendar_start = TimerGameCalendar::ConvertYMDToDate(_settings_game.game_creation.starting_year, 0, 1);
  _network_game_info.clients_max    = _settings_client.network.max_clients;
  _network_game_info.companies_max  = _settings_client.network.max_companies;
  _network_game_info.map_width      = Map::SizeX();
  _network_game_info.map_height     = Map::SizeY();
  _network_game_info.landscape      = _settings_game.game_creation.landscape;
  _network_game_info.dedicated      = _network_dedicated;
  CopyGRFConfigList(_network_game_info.grfconfig, _grfconfig, false);
 
  _network_game_info.server_name = _settings_client.network.server_name;
  _network_game_info.server_revision = GetNetworkRevisionString();
}

const NetworkServerGameInfo &GetCurrentNetworkServerGameInfo()
{
  /* These variables are updated inside _network_game_info as if they are global variables:
   *  - clients_on
   *  - invite_code
   * These don't need to be updated manually here.
   */
  _network_game_info.companies_on  = (uint8_t)Company::GetNumItems();
  _network_game_info.spectators_on = NetworkSpectatorCount();
  _network_game_info.calendar_date = TimerGameCalendar::date;
  _network_game_info.ticks_playing = TimerGameTick::counter;
  return _network_game_info;
}

static void HandleIncomingNetworkGameInfoGRFConfig(GRFConfig &config, std::string_view name)
{
  /* Find the matching GRF file */
  const GRFConfig *f = FindGRFConfig(config.ident.grfid, FGCM_EXACT, &config.ident.md5sum);
  if (f == nullptr) {
    AddGRFTextToList(config.name, name.empty() ? GetString(STR_CONFIG_ERROR_INVALID_GRF_UNKNOWN) : name);
    config.status = GCS_NOT_FOUND;
  } else {
    config.filename = f->filename;
    config.name = f->name;
    config.info = f->info;
    config.url = f->url;
  }
  config.flags.Set(GRFConfigFlag::Copy);
}

void SerializeNetworkGameInfo(Packet &p, const NetworkServerGameInfo &info, bool send_newgrf_names)
{
  p.Send_uint8 (NETWORK_GAME_INFO_VERSION);
 
  /*
   *              Please observe the order.
   * The parts must be read in the same order as they are sent!
   */
 
  /* Update the documentation in game_info.h on changes
   * to the NetworkGameInfo wire-protocol! */
 
  /* NETWORK_GAME_INFO_VERSION = 7 */
  p.Send_uint64(info.ticks_playing);
 
  /* NETWORK_GAME_INFO_VERSION = 6 */
  p.Send_uint8(send_newgrf_names ? NST_GRFID_MD5_NAME : NST_GRFID_MD5);
 
  /* NETWORK_GAME_INFO_VERSION = 5 */
  GameInfo *game_info = Game::GetInfo();
  p.Send_uint32(game_info == nullptr ? -1 : (uint32_t)game_info->GetVersion());
  p.Send_string(game_info == nullptr ? "" : game_info->GetName());
 
  /* NETWORK_GAME_INFO_VERSION = 4 */
  {
    /* Only send the GRF Identification (GRF_ID and MD5 checksum) of
     * the GRFs that are needed, i.e. the ones that the server has
     * selected in the NewGRF GUI and not the ones that are used due
     * to the fact that they are in [newgrf-static] in openttd.cfg */
    uint count = std::ranges::count_if(info.grfconfig, [](const auto &c) { return !c->flags.Test(GRFConfigFlag::Static); });
    p.Send_uint8 (count); // Send number of GRFs
 
    /* Send actual GRF Identifications */
    for (const auto &c : info.grfconfig) {
      if (c->flags.Test(GRFConfigFlag::Static)) continue;
 
      SerializeGRFIdentifier(p, c->ident);
      if (send_newgrf_names) p.Send_string(c->GetName());
    }
  }
 
  /* NETWORK_GAME_INFO_VERSION = 3 */
  p.Send_uint32(info.calendar_date.base());
  p.Send_uint32(info.calendar_start.base());
 
  /* NETWORK_GAME_INFO_VERSION = 2 */
  p.Send_uint8 (info.companies_max);
  p.Send_uint8 (info.companies_on);
  p.Send_uint8 (info.clients_max); // Used to be max-spectators
 
  /* NETWORK_GAME_INFO_VERSION = 1 */
  p.Send_string(info.server_name);
  p.Send_string(info.server_revision);
  p.Send_bool  (info.use_password);
  p.Send_uint8 (info.clients_max);
  p.Send_uint8 (info.clients_on);
  p.Send_uint8 (info.spectators_on);
  p.Send_uint16(info.map_width);
  p.Send_uint16(info.map_height);
  p.Send_uint8 (to_underlying(info.landscape));
  p.Send_bool  (info.dedicated);
}

void DeserializeNetworkGameInfo(Packet &p, NetworkGameInfo &info, const GameInfoNewGRFLookupTable *newgrf_lookup_table)
{
  uint8_t game_info_version = p.Recv_uint8();
  NewGRFSerializationType newgrf_serialisation = NST_GRFID_MD5;
 
  /*
   *              Please observe the order.
   * The parts must be read in the same order as they are sent!
   */
 
  /* Update the documentation in game_info.h on changes
   * to the NetworkGameInfo wire-protocol! */
 
  switch (game_info_version) {
    case 7:
      info.ticks_playing = p.Recv_uint64();
      [[fallthrough]];
 
    case 6:
      newgrf_serialisation = (NewGRFSerializationType)p.Recv_uint8();
      if (newgrf_serialisation >= NST_END) return;
      [[fallthrough]];
 
    case 5: {
      info.gamescript_version = (int)p.Recv_uint32();
      info.gamescript_name = p.Recv_string(NETWORK_NAME_LENGTH);
      [[fallthrough]];
    }
 
    case 4: {
      /* Ensure that the maximum number of NewGRFs and the field in the network
       * protocol are matched to each other. If that is not the case anymore a
       * check must be added to ensure the received data is still valid. */
      static_assert(std::numeric_limits<uint8_t>::max() == NETWORK_MAX_GRF_COUNT);
      uint num_grfs = p.Recv_uint8();
 
      GRFConfigList &dst = info.grfconfig;
      for (uint i = 0; i < num_grfs; i++) {
        NamedGRFIdentifier grf;
        switch (newgrf_serialisation) {
          case NST_GRFID_MD5:
            DeserializeGRFIdentifier(p, grf.ident);
            break;
 
          case NST_GRFID_MD5_NAME:
            DeserializeGRFIdentifierWithName(p, grf);
            break;
 
          case NST_LOOKUP_ID: {
            if (newgrf_lookup_table == nullptr) return;
            auto it = newgrf_lookup_table->find(p.Recv_uint32());
            if (it == newgrf_lookup_table->end()) return;
            grf = it->second;
            break;
          }
 
          default:
            NOT_REACHED();
        }
 
        auto c = std::make_unique<GRFConfig>();
        c->ident = grf.ident;
        HandleIncomingNetworkGameInfoGRFConfig(*c, grf.name);
 
        /* Append GRFConfig to the list */
        dst.push_back(std::move(c));
      }
      [[fallthrough]];
    }
 
    case 3:
      info.calendar_date = TimerGameCalendar::Date{Clamp(p.Recv_uint32(), 0, CalendarTime::MAX_DATE.base())};
      info.calendar_start = TimerGameCalendar::Date{Clamp(p.Recv_uint32(), 0, CalendarTime::MAX_DATE.base())};
      [[fallthrough]];
 
    case 2:
      info.companies_max  = p.Recv_uint8 ();
      info.companies_on   = p.Recv_uint8 ();
      p.Recv_uint8(); // Used to contain max-spectators.
      [[fallthrough]];
 
    case 1:
      info.server_name = p.Recv_string(NETWORK_NAME_LENGTH);
      info.server_revision = p.Recv_string(NETWORK_REVISION_LENGTH);
      if (game_info_version < 6) p.Recv_uint8 (); // Used to contain server-lang.
      info.use_password   = p.Recv_bool  ();
      info.clients_max    = p.Recv_uint8 ();
      info.clients_on     = p.Recv_uint8 ();
      info.spectators_on  = p.Recv_uint8 ();
      if (game_info_version < 3) { // 16 bits dates got scrapped and are read earlier
        info.calendar_date = CalendarTime::DAYS_TILL_ORIGINAL_BASE_YEAR + p.Recv_uint16();
        info.calendar_start = CalendarTime::DAYS_TILL_ORIGINAL_BASE_YEAR + p.Recv_uint16();
      }
      if (game_info_version < 6) while (p.Recv_uint8() != 0) {} // Used to contain the map-name.
      info.map_width      = p.Recv_uint16();
      info.map_height     = p.Recv_uint16();
      info.landscape      = LandscapeType{p.Recv_uint8()};
      info.dedicated      = p.Recv_bool  ();
 
      if (to_underlying(info.landscape) >= NUM_LANDSCAPE) info.landscape = LandscapeType::Temperate;
  }
 
  /* For older servers, estimate the ticks running based on the calendar date. */
  if (game_info_version < 7) {
    info.ticks_playing = static_cast<uint64_t>(std::max(0, info.calendar_date.base() - info.calendar_start.base())) * Ticks::DAY_TICKS;
  }
}

void SerializeGRFIdentifier(Packet &p, const GRFIdentifier &grf)
{
  p.Send_uint32(grf.grfid);
  p.Send_bytes(grf.md5sum);
}

void DeserializeGRFIdentifier(Packet &p, GRFIdentifier &grf)
{
  grf.grfid = p.Recv_uint32();
  p.Recv_bytes(grf.md5sum);
}

void DeserializeGRFIdentifierWithName(Packet &p, NamedGRFIdentifier &grf)
{
  DeserializeGRFIdentifier(p, grf.ident);
  grf.name = p.Recv_string(NETWORK_GRF_NAME_LENGTH);
}