Feature: join servers based on their invite code

This removes the need to know a server IP to join it. Invite codes
are small (~7 characters) indentifiers for servers, which can be
exchanged with other players to join the servers.

src/console_cmds.cpp

@@ -702,6 +702,7 @@ DEF_CONSOLE_CMD(ConServerInfo)
 		return true;
 	}
 
+	IConsolePrint(CC_DEFAULT, "Invite code:                {}", _network_server_invite_code);
 	IConsolePrint(CC_DEFAULT, "Current/maximum clients:    {:3d}/{:3d}", _network_game_info.clients_on, _settings_client.network.max_clients);
 	IConsolePrint(CC_DEFAULT, "Current/maximum companies:  {:3d}/{:3d}", Company::GetNumItems(), _settings_client.network.max_companies);
 	IConsolePrint(CC_DEFAULT, "Current/maximum spectators: {:3d}/{:3d}", NetworkSpectatorCount(), _settings_client.network.max_spectators);

src/lang/english.txt

@@ -2045,12 +2045,12 @@ STR_NETWORK_SERVER_LIST_SEARCH_SERVER_INTERNET_TOOLTIP          :{BLACK}Search i
 STR_NETWORK_SERVER_LIST_SEARCH_SERVER_LAN                       :{BLACK}Search LAN
 STR_NETWORK_SERVER_LIST_SEARCH_SERVER_LAN_TOOLTIP               :{BLACK}Search local area network for servers
 STR_NETWORK_SERVER_LIST_ADD_SERVER                              :{BLACK}Add server
-STR_NETWORK_SERVER_LIST_ADD_SERVER_TOOLTIP                      :{BLACK}Adds a server to the list which will always be checked for running games
+STR_NETWORK_SERVER_LIST_ADD_SERVER_TOOLTIP                      :{BLACK}Adds a server to the list. This can either be a server address or an invite code
 STR_NETWORK_SERVER_LIST_START_SERVER                            :{BLACK}Start server
 STR_NETWORK_SERVER_LIST_START_SERVER_TOOLTIP                    :{BLACK}Start your own server
 
 STR_NETWORK_SERVER_LIST_PLAYER_NAME_OSKTITLE                    :{BLACK}Enter your name
-STR_NETWORK_SERVER_LIST_ENTER_IP                                :{BLACK}Enter the address of the host
+STR_NETWORK_SERVER_LIST_ENTER_SERVER_ADDRESS                    :{BLACK}Enter server address or invite code
 
 # Start new multiplayer server
 STR_NETWORK_START_SERVER_CAPTION                                :{WHITE}Start new multiplayer game
@@ -2136,6 +2136,8 @@ STR_NETWORK_CLIENT_LIST_SERVER_NAME_EDIT_TOOLTIP                :{BLACK}Edit the
 STR_NETWORK_CLIENT_LIST_SERVER_NAME_QUERY_CAPTION               :Name of the server
 STR_NETWORK_CLIENT_LIST_SERVER_VISIBILITY                       :{BLACK}Visibility
 STR_NETWORK_CLIENT_LIST_SERVER_VISIBILITY_TOOLTIP               :{BLACK}Whether other people can see your server in the public listing
+STR_NETWORK_CLIENT_LIST_SERVER_INVITE_CODE                      :{BLACK}Invite code
+STR_NETWORK_CLIENT_LIST_SERVER_INVITE_CODE_TOOLTIP              :{BLACK}Invite code other players can use to join this server
 STR_NETWORK_CLIENT_LIST_SERVER_CONNECTION_TYPE                  :{BLACK}Connection type
 STR_NETWORK_CLIENT_LIST_SERVER_CONNECTION_TYPE_TOOLTIP          :{BLACK}Whether and how your server can be reached by others
 STR_NETWORK_CLIENT_LIST_PLAYER                                  :{BLACK}Player

src/network/core/config.h

@@ -47,7 +47,7 @@ static const uint16 COMPAT_MTU                      = 1460;           ///< Numbe
 static const byte NETWORK_GAME_ADMIN_VERSION        =    1;           ///< What version of the admin network do we use?
 static const byte NETWORK_GAME_INFO_VERSION         =    4;           ///< What version of game-info do we use?
 static const byte NETWORK_COMPANY_INFO_VERSION      =    6;           ///< What version of company info is this?
-static const byte NETWORK_COORDINATOR_VERSION       =    1;           ///< What version of game-coordinator-protocol do we use?
+static const byte NETWORK_COORDINATOR_VERSION       =    2;           ///< What version of game-coordinator-protocol do we use?
 
 static const uint NETWORK_NAME_LENGTH               =   80;           ///< The maximum length of the server name and map name, in bytes including '\0'
 static const uint NETWORK_COMPANY_NAME_LENGTH       =  128;           ///< The maximum length of the company name, in bytes including '\0'
@@ -67,7 +67,10 @@ static const uint NETWORK_CONTENT_VERSION_LENGTH    =   16;           ///< The m
 static const uint NETWORK_CONTENT_URL_LENGTH        =   96;           ///< The maximum length of a content's url, in bytes including '\0'.
 static const uint NETWORK_CONTENT_DESC_LENGTH       =  512;           ///< The maximum length of a content's description, in bytes including '\0'.
 static const uint NETWORK_CONTENT_TAG_LENGTH        =   32;           ///< The maximum length of a content's tag, in bytes including '\0'.
-static const uint NETWORK_ERROR_DETAIL_LENGTH        = 100;           ///< The maximum length of the error detail, in bytes including '\0'
+static const uint NETWORK_ERROR_DETAIL_LENGTH       =  100;           ///< The maximum length of the error detail, in bytes including '\0'.
+static const uint NETWORK_INVITE_CODE_LENGTH        =   64;           ///< The maximum length of the invite code, in bytes including '\0'.
+static const uint NETWORK_INVITE_CODE_SECRET_LENGTH =   80;           ///< The maximum length of the invite code secret, in bytes including '\0'.
+static const uint NETWORK_TOKEN_LENGTH              =   64;           ///< The maximum length of a token, in bytes including '\0'.
 
 static const uint NETWORK_GRF_NAME_LENGTH           =   80;           ///< Maximum length of the name of a GRF
 

src/network/core/game_info.cpp

@@ -141,7 +141,11 @@ void FillStaticNetworkServerGameInfo()
  */
 const NetworkServerGameInfo *GetCurrentNetworkServerGameInfo()
 {
-	/* Client_on is used as global variable to keep track on the number of clients. */
+	/* 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  = (byte)Company::GetNumItems();
 	_network_game_info.spectators_on = NetworkSpectatorCount();
 	_network_game_info.game_date     = _date;

src/network/core/tcp_connect.cpp

@@ -13,6 +13,7 @@
 #include "../../thread.h"
 
 #include "tcp.h"
+#include "../network_coordinator.h"
 #include "../network_internal.h"
 
 #include <deque>
@@ -47,7 +48,7 @@ TCPServerConnecter::TCPServerConnecter(const std::string &connection_string, uin
 			break;
 
 		case SERVER_ADDRESS_INVITE_CODE:
-			// TODO -- The next commit will add this functionality.
+			_network_coordinator_client.ConnectToServer(this->server_address.connection_string, this);
 			break;
 
 		default:

src/network/core/tcp_coordinator.cpp

@@ -27,12 +27,18 @@ bool NetworkCoordinatorSocketHandler::HandlePacket(Packet *p)
 	PacketCoordinatorType type = (PacketCoordinatorType)p->Recv_uint8();
 
 	switch (type) {
-		case PACKET_COORDINATOR_GC_ERROR:        return this->Receive_GC_ERROR(p);
-		case PACKET_COORDINATOR_SERVER_REGISTER: return this->Receive_SERVER_REGISTER(p);
-		case PACKET_COORDINATOR_GC_REGISTER_ACK: return this->Receive_GC_REGISTER_ACK(p);
-		case PACKET_COORDINATOR_SERVER_UPDATE:   return this->Receive_SERVER_UPDATE(p);
-		case PACKET_COORDINATOR_CLIENT_LISTING:  return this->Receive_CLIENT_LISTING(p);
-		case PACKET_COORDINATOR_GC_LISTING:      return this->Receive_GC_LISTING(p);
+		case PACKET_COORDINATOR_GC_ERROR:              return this->Receive_GC_ERROR(p);
+		case PACKET_COORDINATOR_SERVER_REGISTER:       return this->Receive_SERVER_REGISTER(p);
+		case PACKET_COORDINATOR_GC_REGISTER_ACK:       return this->Receive_GC_REGISTER_ACK(p);
+		case PACKET_COORDINATOR_SERVER_UPDATE:         return this->Receive_SERVER_UPDATE(p);
+		case PACKET_COORDINATOR_CLIENT_LISTING:        return this->Receive_CLIENT_LISTING(p);
+		case PACKET_COORDINATOR_GC_LISTING:            return this->Receive_GC_LISTING(p);
+		case PACKET_COORDINATOR_CLIENT_CONNECT:        return this->Receive_CLIENT_CONNECT(p);
+		case PACKET_COORDINATOR_GC_CONNECTING:         return this->Receive_GC_CONNECTING(p);
+		case PACKET_COORDINATOR_SERCLI_CONNECT_FAILED: return this->Receive_SERCLI_CONNECT_FAILED(p);
+		case PACKET_COORDINATOR_GC_CONNECT_FAILED:     return this->Receive_GC_CONNECT_FAILED(p);
+		case PACKET_COORDINATOR_CLIENT_CONNECTED:      return this->Receive_CLIENT_CONNECTED(p);
+		case PACKET_COORDINATOR_GC_DIRECT_CONNECT:     return this->Receive_GC_DIRECT_CONNECT(p);
 
 		default:
 			Debug(net, 0, "[tcp/coordinator] Received invalid packet type {}", type);
@@ -82,3 +88,9 @@ bool NetworkCoordinatorSocketHandler::Receive_GC_REGISTER_ACK(Packet *p) { retur
 bool NetworkCoordinatorSocketHandler::Receive_SERVER_UPDATE(Packet *p) { return this->ReceiveInvalidPacket(PACKET_COORDINATOR_SERVER_UPDATE); }
 bool NetworkCoordinatorSocketHandler::Receive_CLIENT_LISTING(Packet *p) { return this->ReceiveInvalidPacket(PACKET_COORDINATOR_CLIENT_LISTING); }
 bool NetworkCoordinatorSocketHandler::Receive_GC_LISTING(Packet *p) { return this->ReceiveInvalidPacket(PACKET_COORDINATOR_GC_LISTING); }
+bool NetworkCoordinatorSocketHandler::Receive_CLIENT_CONNECT(Packet *p) { return this->ReceiveInvalidPacket(PACKET_COORDINATOR_CLIENT_CONNECT); }
+bool NetworkCoordinatorSocketHandler::Receive_GC_CONNECTING(Packet *p) { return this->ReceiveInvalidPacket(PACKET_COORDINATOR_GC_CONNECTING); }
+bool NetworkCoordinatorSocketHandler::Receive_SERCLI_CONNECT_FAILED(Packet *p) { return this->ReceiveInvalidPacket(PACKET_COORDINATOR_SERCLI_CONNECT_FAILED); }
+bool NetworkCoordinatorSocketHandler::Receive_GC_CONNECT_FAILED(Packet *p) { return this->ReceiveInvalidPacket(PACKET_COORDINATOR_GC_CONNECT_FAILED); }
+bool NetworkCoordinatorSocketHandler::Receive_CLIENT_CONNECTED(Packet *p) { return this->ReceiveInvalidPacket(PACKET_COORDINATOR_CLIENT_CONNECTED); }
+bool NetworkCoordinatorSocketHandler::Receive_GC_DIRECT_CONNECT(Packet *p) { return this->ReceiveInvalidPacket(PACKET_COORDINATOR_GC_DIRECT_CONNECT); }

src/network/core/tcp_coordinator.h

@@ -23,15 +23,22 @@
  * GC     -> packets from Game Coordinator to either Client or Server.
  * SERVER -> packets from Server to Game Coordinator.
  * CLIENT -> packets from Client to Game Coordinator.
+ * SERCLI -> packets from either the Server or Client to Game Coordinator.
  **/
 enum PacketCoordinatorType {
-	PACKET_COORDINATOR_GC_ERROR,        ///< Game Coordinator indicates there was an error.
-	PACKET_COORDINATOR_SERVER_REGISTER, ///< Server registration.
-	PACKET_COORDINATOR_GC_REGISTER_ACK, ///< Game Coordinator accepts the registration.
-	PACKET_COORDINATOR_SERVER_UPDATE,   ///< Server sends an set intervals an update of the server.
-	PACKET_COORDINATOR_CLIENT_LISTING,  ///< Client is requesting a listing of all public servers.
-	PACKET_COORDINATOR_GC_LISTING,      ///< Game Coordinator returns a listing of all public servers.
-	PACKET_COORDINATOR_END,             ///< Must ALWAYS be on the end of this list!! (period).
+	PACKET_COORDINATOR_GC_ERROR,              ///< Game Coordinator indicates there was an error.
+	PACKET_COORDINATOR_SERVER_REGISTER,       ///< Server registration.
+	PACKET_COORDINATOR_GC_REGISTER_ACK,       ///< Game Coordinator accepts the registration.
+	PACKET_COORDINATOR_SERVER_UPDATE,         ///< Server sends an set intervals an update of the server.
+	PACKET_COORDINATOR_CLIENT_LISTING,        ///< Client is requesting a listing of all public servers.
+	PACKET_COORDINATOR_GC_LISTING,            ///< Game Coordinator returns a listing of all public servers.
+	PACKET_COORDINATOR_CLIENT_CONNECT,        ///< Client wants to connect to a server based on an invite code.
+	PACKET_COORDINATOR_GC_CONNECTING,         ///< Game Coordinator informs the client of the token assigned to the connection attempt.
+	PACKET_COORDINATOR_SERCLI_CONNECT_FAILED, ///< Client/server tells the Game Coordinator the current connection attempt failed.
+	PACKET_COORDINATOR_GC_CONNECT_FAILED,     ///< Game Coordinator informs client/server it has given up on the connection attempt.
+	PACKET_COORDINATOR_CLIENT_CONNECTED,      ///< Client informs the Game Coordinator the connection with the server is established.
+	PACKET_COORDINATOR_GC_DIRECT_CONNECT,     ///< Game Coordinator tells client to directly connect to the hostname:port of the server.
+	PACKET_COORDINATOR_END,                   ///< Must ALWAYS be on the end of this list!! (period)
 };
 
 /**
@@ -49,6 +56,7 @@ enum ConnectionType {
 enum NetworkCoordinatorErrorType {
 	NETWORK_COORDINATOR_ERROR_UNKNOWN,             ///< There was an unknown error.
 	NETWORK_COORDINATOR_ERROR_REGISTRATION_FAILED, ///< Your request for registration failed.
+	NETWORK_COORDINATOR_ERROR_INVALID_INVITE_CODE, ///< The invite code given is invalid.
 };
 
 /** Base socket handler for all Game Coordinator TCP sockets. */
@@ -76,6 +84,8 @@ class NetworkCoordinatorSocketHandler : public NetworkTCPSocketHandler {
 	 *  uint8   Game Coordinator protocol version.
 	 *  uint8   Type of game (see ServerGameType).
 	 *  uint16  Local port of the server.
+	 *  string  Invite code the server wants to use (can be empty; coordinator will assign a new invite code).
+	 *  string  Secret that belongs to the invite code (empty if invite code is empty).
 	 *
 	 * @param p The packet that was just received.
 	 * @return True upon success, otherwise false.
@@ -85,6 +95,8 @@ class NetworkCoordinatorSocketHandler : public NetworkTCPSocketHandler {
 	/**
 	 * Game Coordinator acknowledges the registration.
 	 *
+	 *  string  Invite code that can be used to join this server.
+	 *  string  Secret that belongs to the invite code (only needed if reusing the invite code on next CLIENT_REGISTER).
 	 *  uint8   Type of connection was detected (see ConnectionType).
 	 *
 	 * @param p The packet that was just received.
@@ -130,6 +142,79 @@ class NetworkCoordinatorSocketHandler : public NetworkTCPSocketHandler {
 	 */
 	virtual bool Receive_GC_LISTING(Packet *p);
 
+	/**
+	 * Client wants to connect to a Server.
+	 *
+	 *  uint8   Game Coordinator protocol version.
+	 *  string  Invite code of the Server to join.
+	 *
+	 * @param p The packet that was just received.
+	 * @return True upon success, otherwise false.
+	 */
+	virtual bool Receive_CLIENT_CONNECT(Packet *p);
+
+	/**
+	 * Game Coordinator informs the Client under what token it will start the
+	 * attempt to connect the Server and Client together.
+	 *
+	 *  string  Token to track the current connect request.
+	 *  string  Invite code of the Server to join.
+	 *
+	 * @param p The packet that was just received.
+	 * @return True upon success, otherwise false.
+	 */
+	virtual bool Receive_GC_CONNECTING(Packet *p);
+
+	/**
+	 * Client or Server failed to connect to the remote side.
+	 *
+	 *  uint8   Game Coordinator protocol version.
+	 *  string  Token to track the current connect request.
+	 *  uint8   Tracking number to track current connect request.
+	 *
+	 * @param p The packet that was just received.
+	 * @return True upon success, otherwise false.
+	 */
+	virtual bool Receive_SERCLI_CONNECT_FAILED(Packet *p);
+
+	/**
+	 * Game Coordinator informs the Client that it failed to find a way to
+	 * connect the Client to the Server. Any open connections for this token
+	 * should be closed now.
+	 *
+	 *  string  Token to track the current connect request.
+	 *
+	 * @param p The packet that was just received.
+	 * @return True upon success, otherwise false.
+	 */
+	virtual bool Receive_GC_CONNECT_FAILED(Packet *p);
+
+	/**
+	 * Client informs the Game Coordinator the connection with the Server is
+	 * established. The Client will disconnect from the Game Coordinator next.
+	 *
+	 *  uint8   Game Coordinator protocol version.
+	 *  string  Token to track the current connect request.
+	 *
+	 * @param p The packet that was just received.
+	 * @return True upon success, otherwise false.
+	 */
+	virtual bool Receive_CLIENT_CONNECTED(Packet *p);
+
+	/**
+	 * Game Coordinator requests that the Client makes a direct connection to
+	 * the indicated peer, which is a Server.
+	 *
+	 *  string  Token to track the current connect request.
+	 *  uint8   Tracking number to track current connect request.
+	 *  string  Hostname of the peer.
+	 *  uint16  Port of the peer.
+	 *
+	 * @param p The packet that was just received.
+	 * @return True upon success, otherwise false.
+	 */
+	virtual bool Receive_GC_DIRECT_CONNECT(Packet *p);
+
 	bool HandlePacket(Packet *p);
 public:
 	/**

src/network/network.cpp

@@ -589,9 +589,13 @@ void NetworkClose(bool close_admins)
 		ServerNetworkAdminSocketHandler::CloseListeners();
 
 		_network_coordinator_client.CloseConnection();
-	} else if (MyClient::my_client != nullptr) {
-		MyClient::SendQuit();
-		MyClient::my_client->CloseConnection(NETWORK_RECV_STATUS_CLIENT_QUIT);
+	} else {
+		if (MyClient::my_client != nullptr) {
+			MyClient::SendQuit();
+			MyClient::my_client->CloseConnection(NETWORK_RECV_STATUS_CLIENT_QUIT);
+		}
+
+		_network_coordinator_client.CloseAllTokens();
 	}
 
 	TCPConnecter::KillAll();