Fix: as client, try to reconnect more than once on server restart

src/lang/english.txt

@@ -2640,6 +2640,7 @@ STR_NETWORK_MESSAGE_GIVE_MONEY                                  :*** {0:RAW_STRI
 STR_NETWORK_MESSAGE_SERVER_SHUTDOWN                             :{WHITE}The server closed the session
 STR_NETWORK_MESSAGE_SERVER_REBOOT                               :{WHITE}The server is restarting...{}Please wait...
 STR_NETWORK_MESSAGE_KICKED                                      :*** {RAW_STRING} was kicked. Reason: ({RAW_STRING})
+STR_NETWORK_MESSAGE_SERVER_REBOOT_REJOIN_FAILED                 :{WHITE}Failed to reconnect to server
 
 STR_NETWORK_ERROR_COORDINATOR_REGISTRATION_FAILED               :{WHITE}Server registration failed
 STR_NETWORK_ERROR_COORDINATOR_REUSE_OF_INVITE_CODE              :{WHITE}Another server with the same invite-code registered itself. Switching to "local" game-type.

src/network/core/config.h

@@ -74,6 +74,8 @@ static const uint NETWORK_TOKEN_LENGTH              =   64;           ///< The m
 
 static const uint NETWORK_GRF_NAME_LENGTH           =   80;           ///< Maximum length of the name of a GRF
 
+static const uint32_t NETWORK_RECONNECT_ATTEMPTS    =    8;           ///< How many attempts before we give up reconnecting.
+
 /**
  * Maximum number of GRFs that can be sent.
  *

src/network/network.cpp

@@ -64,7 +64,9 @@ bool _is_network_server;  ///< Does this client wants to be a network-server?
 NetworkCompanyState *_network_company_states = nullptr; ///< Statistics about some companies.
 ClientID _network_own_client_id;      ///< Our client identifier.
 ClientID _redirect_console_to_client; ///< If not invalid, redirect the console output to a client.
-uint8_t _network_reconnect;             ///< Reconnect timeout
+uint32_t _network_reconnect_attempts = 0; ///< How many attempts to reconnect left.
+std::chrono::seconds _network_reconnect_backoff = {}; ///< How much time to wait for the next reconnect attempt.
+std::chrono::steady_clock::time_point _network_reconnect = {}; ///< The time when to attempt another reconnect.
 StringList _network_bind_list;        ///< The addresses to bind on.
 StringList _network_host_list;        ///< The servers we know.
 StringList _network_ban_list;         ///< The banned clients.
@@ -619,8 +621,6 @@ static void NetworkInitialize(bool close_admins = true)
 
 	_sync_frame = 0;
 	_network_first_time = true;
-
-	_network_reconnect = 0;
 }
 
 /** Non blocking connection to query servers for their game info. */
@@ -738,7 +738,9 @@ public:
 	{
 		Debug(net, 9, "Client::OnFailure(): connection_string={}", this->connection_string);
 
-		ShowNetworkError(STR_NETWORK_ERROR_NOCONNECTION);
+		if (_network_reconnect_attempts == 0) {
+			ShowNetworkError(STR_NETWORK_ERROR_NOCONNECTION);
+		}
 	}
 
 	void OnConnect(SOCKET s) override

src/network/network_client.cpp

@@ -344,6 +344,8 @@ NetworkRecvStatus ClientNetworkGameSocketHandler::SendJoin()
 	_network_join_status = NETWORK_JOIN_STATUS_AUTHORIZING;
 	SetWindowDirty(WC_NETWORK_STATUS_WINDOW, WN_NETWORK_STATUS_WINDOW_JOIN);
 
+	_network_reconnect_attempts = 0;
+
 	auto p = std::make_unique<Packet>(PACKET_CLIENT_JOIN);
 	p->Send_string(GetNetworkRevisionString());
 	p->Send_uint32(_openttd_newgrf_version);
@@ -1124,14 +1126,10 @@ NetworkRecvStatus ClientNetworkGameSocketHandler::Receive_SERVER_NEWGAME(Packet
 {
 	Debug(net, 9, "Client::Receive_SERVER_NEWGAME()");
 
-	/* Only when we're trying to join we really
-	 * care about the server shutting down. */
 	if (this->status >= STATUS_JOIN) {
-		/* To throttle the reconnects a bit, every clients waits its
-		 * Client ID modulo 16 + 1 (value 0 means no reconnect).
-		 * This way reconnects should be spread out a bit. */
-		_network_reconnect = _network_own_client_id % 16 + 1;
-		ShowErrorMessage(STR_NETWORK_MESSAGE_SERVER_REBOOT, INVALID_STRING_ID, WL_CRITICAL);
+		_network_reconnect_attempts = NETWORK_RECONNECT_ATTEMPTS;
+		_network_reconnect_backoff = std::chrono::seconds(1);
+		_network_reconnect = std::chrono::steady_clock::now() + _network_reconnect_backoff;
 	}
 
 	if (this->status == STATUS_ACTIVE) ClientNetworkEmergencySave();

src/network/network_func.h

@@ -28,7 +28,9 @@ extern NetworkCompanyState *_network_company_states;
 
 extern ClientID _network_own_client_id;
 extern ClientID _redirect_console_to_client;
-extern uint8_t _network_reconnect;
+extern uint32_t _network_reconnect_attempts;
+extern std::chrono::seconds _network_reconnect_backoff;
+extern std::chrono::steady_clock::time_point _network_reconnect;
 extern StringList _network_bind_list;
 extern StringList _network_host_list;
 extern StringList _network_ban_list;

src/network/network_internal.h

@@ -91,8 +91,6 @@ extern std::string _network_server_invite_code;
 /* Variable available for clients. */
 extern std::string _network_server_name;
 
-extern uint8_t _network_reconnect;
-
 extern CompanyMask _network_company_passworded;
 
 void NetworkQueryServer(const std::string &connection_string);

src/openttd.cpp

@@ -1598,11 +1598,30 @@ void GameLoop()
 		/* Multiplayer */
 		NetworkGameLoop();
 	} else {
-		if (_network_reconnect > 0 && --_network_reconnect == 0) {
-			/* This means that we want to reconnect to the last host
-			 * We do this here, because it means that the network is really closed */
-			NetworkClientConnectGame(_settings_client.network.last_joined, COMPANY_SPECTATOR);
+		if (_network_reconnect_attempts > 0 && std::chrono::steady_clock::now() > _network_reconnect) {
+			Debug(net, 3, "Reconnect attempt #{}", _network_reconnect_attempts);
+
+			_network_reconnect_attempts--;
+			_network_reconnect_backoff = std::min(_network_reconnect_backoff * 2, std::chrono::seconds(30));
+			_network_reconnect = std::chrono::steady_clock::now() + _network_reconnect_backoff;
+
+			if (_network_reconnect_attempts == 0) {
+				ShowErrorMessage(STR_NETWORK_MESSAGE_SERVER_REBOOT_REJOIN_FAILED, INVALID_STRING_ID, WL_ERROR);
+			} else {
+				/* Show that we are reconnecting the first time we do an attempt.
+				 * We have to do it this late, as switching to the main menu closes
+				 * all errors (except critical, but this isn't critical). */
+				if (_network_reconnect_attempts == NETWORK_RECONNECT_ATTEMPTS - 1) {
+					ShowErrorMessage(STR_NETWORK_MESSAGE_SERVER_REBOOT, INVALID_STRING_ID, WL_ERROR);
+				}
+
+				/* If the AskRelay window is open, don't start a new connect. */
+				if (FindWindowByClass(WC_NETWORK_ASK_RELAY) == nullptr) {
+					NetworkClientConnectGame(_settings_client.network.last_joined, COMPANY_SPECTATOR);
+				}
+			}
 		}
+
 		/* Singleplayer */
 		StateGameLoop();
 	}