Allow hosting matches with 8 players and up to 16 observers, fixes #3254.

The host can change the number of allowed observers in running games.

Make sure that joining observers won't take the "slot" of disconnected
players, fixes #3671.

Send clients a new disconnect reason "Server full" instead of letting
them timeout.

This was SVN commit r17881.

binaries/data/config/default.cfg

@@ -354,6 +354,7 @@ enabledmods = "mod public"
 [network]
 duplicateplayernames = false      ; Rename joining player to "User (2)" if "User" is already connected, otherwise prohibit join.
 lateobserverjoins = false         ; Allow observers to join the game after it started
+observerlimit = 6                 ; Prevent further observer joins in running games if this limit is reached
 
 [overlay]
 fps = "false"                     ; Show frames per second in top right corner

binaries/data/mods/public/gui/common/network.js

@@ -58,6 +58,7 @@ function getDisconnectReason(id)
 	case 5: return translate("You have been kicked");
 	case 6: return translate("You have been banned");
 	case 7: return translate("Playername in use. If you were disconnected, retry in few seconds");
+	case 8: return translate("Server full");
 	default:
 		warn("Unknown disconnect-reason ID received: " + id);
 		return sprintf(translate("\\[Invalid value %(id)s]"), { "id": id });

binaries/data/mods/public/gui/options/options.json

@@ -66,6 +66,12 @@
 			"label": "Late Observer Joins",
 			"tooltip": "Allow observers to join the game after it started",
 			"parameters": { "config": "network.lateobserverjoins" }
+		},
+		{
+			"type": "number",
+			"label": "Observer Limit",
+			"tooltip": "Prevent further observer from joining if the limit is reached",
+			"parameters": { "config": "network.observerlimit", "min": 0, "max": 16 }
 		}
 	],
 	"graphicsSetting":

source/network/NetHost.h

@@ -66,7 +66,8 @@ enum NetDisconnectReason
 	NDR_SERVER_ALREADY_IN_GAME,
 	NDR_KICKED,
 	NDR_BANNED,
-	NDR_PLAYERNAME_IN_USE
+	NDR_PLAYERNAME_IN_USE,
+	NDR_SERVER_FULL
 };
 
 class CNetHost

source/network/NetMessages.h

@@ -28,7 +28,7 @@
 
 #define PS_PROTOCOL_MAGIC				0x5073013f		// 'P', 's', 0x01, '?'
 #define PS_PROTOCOL_MAGIC_RESPONSE		0x50630121		// 'P', 'c', 0x01, '!'
-#define PS_PROTOCOL_VERSION				0x01010010		// Arbitrary protocol
+#define PS_PROTOCOL_VERSION				0x01010011		// Arbitrary protocol
 #define PS_DEFAULT_PORT					0x5073			// 'P', 's'
 
 // Defines the list of message types. The order of the list must not change.

source/network/NetServer.cpp

@@ -39,9 +39,16 @@
 #include <miniupnpc/upnperrors.h>
 #endif
 
+/**
+ * Number of peers to allocate for the enet host.
+ * Limited by ENET_PROTOCOL_MAXIMUM_PEER_ID (4096).
+ *
+ * At most 8 players, 16 observers and 1 temporary connection to send the "server full" disconnect-reason.
+ */
+#define MAX_CLIENTS 25
+
 #define	DEFAULT_SERVER_NAME			L"Unnamed Server"
 #define DEFAULT_WELCOME_MESSAGE		L"Welcome"
-#define MAX_CLIENTS					10
 
 static const int CHANNEL_COUNT = 1;
 
@@ -929,19 +936,39 @@ bool CNetServerWorker::OnAuthenticate(void* context, CFsmEvent* event)
 	bool observerLateJoin = false;
 	CFG_GET_VAL("network.lateobserverjoins", observerLateJoin);
 
-	// If the game has already started, only allow rejoins
+	int maxObservers = 0;
+	CFG_GET_VAL("network.observerlimit", maxObservers);
+
 	bool isRejoining = false;
-	if (server.m_State != SERVER_STATE_PREGAME)
+	bool serverFull = false;
+	if (server.m_State == SERVER_STATE_PREGAME)
 	{
-		// Search for an old disconnected player of the same name
+		// Don't check for maxObservers in the gamesetup, as we don't know yet who will be assigned
+		serverFull = server.m_Sessions.size() >= MAX_CLIENTS;
+	}
+	else
+	{
+		isRejoining = observerLateJoin;
+		bool isObserver = true;
+		int disconnectedPlayers = 0;
+		int connectedPlayers = 0;
 		// (TODO: if GUIDs were stable, we should use them instead)
-		isRejoining =
-			observerLateJoin ||
-			std::find_if(
-				server.m_PlayerAssignments.begin(), server.m_PlayerAssignments.end(),
-				[&username] (const std::pair<CStr, PlayerAssignment>& pair)
-				{ return !pair.second.m_Enabled && pair.second.m_Name == username; })
-			!= server.m_PlayerAssignments.end();
+		for (PlayerAssignmentMap::iterator it = server.m_PlayerAssignments.begin(); it != server.m_PlayerAssignments.end(); ++it)
+		{
+			if (!it->second.m_Enabled && it->second.m_Name == username)
+			{
+				isObserver = it->second.m_PlayerID == -1;
+				isRejoining = true;
+			}
+
+			if (it->second.m_PlayerID == -1)
+				continue;
+
+			if (it->second.m_Enabled)
+				++connectedPlayers;
+			else
+				++disconnectedPlayers;
+		}
 
 		// Players who weren't already in the game are not allowed to join now that it's started
 		if (!isRejoining)
@@ -950,6 +977,17 @@ bool CNetServerWorker::OnAuthenticate(void* context, CFsmEvent* event)
 			session->Disconnect(NDR_SERVER_ALREADY_IN_GAME);
 			return true;
 		}
+
+		// Ensure all players will be able to rejoin
+		serverFull = isObserver && (
+			(int) server.m_Sessions.size() - connectedPlayers > maxObservers ||
+			(int) server.m_Sessions.size() + disconnectedPlayers >= MAX_CLIENTS);
+	}
+
+	if (serverFull)
+	{
+		session->Disconnect(NDR_SERVER_FULL);
+		return true;
 	}
 
 	// TODO: check server password etc?