From 9ec4ba38246c2841661da7c191f5f40e81be78da Mon Sep 17 00:00:00 2001
From: Louis-Antoine <lamr@free.fr>
Date: Fri, 24 Apr 2020 14:05:15 +0200
Subject: [PATCH] Add a minimum delay between connections

---
 src/d_clisrv.c | 22 ++++++++++++++++++++++
 src/d_clisrv.h |  2 +-
 src/d_netcmd.c |  1 +
 3 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/src/d_clisrv.c b/src/d_clisrv.c
index 3603bb20d..f7755c148 100644
--- a/src/d_clisrv.c
+++ b/src/d_clisrv.c
@@ -85,6 +85,10 @@ tic_t jointimeout = (10*TICRATE);
 static boolean sendingsavegame[MAXNETNODES]; // Are we sending the savegame?
 static tic_t freezetimeout[MAXNETNODES]; // Until when can this node freeze the server before getting a timeout?
 
+// Incremented by cv_joindelay when a client joins, decremented each tic.
+// If higher than cv_joindelay * 2 (3 joins in a short timespan), joins are temporarily disabled.
+static tic_t joindelay = 0;
+
 UINT16 pingmeasurecount = 1;
 UINT32 realpingtable[MAXPLAYERS]; //the base table of ping where an average will be sent to everyone.
 UINT32 playerpingtable[MAXPLAYERS]; //table of player latency values.
@@ -3077,6 +3081,8 @@ consvar_t cv_allownewplayer = {"allowjoin", "On", CV_NETVAR, CV_OnOff, NULL, 0,
 consvar_t cv_joinnextround = {"joinnextround", "Off", CV_NETVAR, CV_OnOff, NULL, 0, NULL, NULL, 0, 0, NULL}; /// \todo not done
 static CV_PossibleValue_t maxplayers_cons_t[] = {{2, "MIN"}, {32, "MAX"}, {0, NULL}};
 consvar_t cv_maxplayers = {"maxplayers", "8", CV_SAVE, maxplayers_cons_t, NULL, 0, NULL, NULL, 0, 0, NULL};
+static CV_PossibleValue_t joindelay_cons_t[] = {{1, "MIN"}, {3600, "MAX"}, {0, "Off"}, {0, NULL}};
+consvar_t cv_joindelay = {"joindelay", "10", CV_SAVE, joindelay_cons_t, NULL, 0, NULL, NULL, 0, 0, NULL};
 static CV_PossibleValue_t rejointimeout_cons_t[] = {{1, "MIN"}, {60 * FRACUNIT, "MAX"}, {0, "Off"}, {0, NULL}};
 consvar_t cv_rejointimeout = {"rejointimeout", "Off", CV_SAVE|CV_FLOAT, rejointimeout_cons_t, NULL, 0, NULL, NULL, 0, 0, NULL};
 
@@ -3164,6 +3170,8 @@ void SV_ResetServer(void)
 	neededtic = maketic;
 	tictoclear = maketic;
 
+	joindelay = 0;
+
 	for (i = 0; i < MAXNETNODES; i++)
 		ResetNode(i);
 
@@ -3613,6 +3621,9 @@ static void HandleConnect(SINT8 node)
 		SV_SendRefuse(node, M_GetText("No players from\nthis node."));
 	else if (luafiletransfers)
 		SV_SendRefuse(node, M_GetText("The server is broadcasting a file\nrequested by a Lua script.\nPlease wait a bit and then\ntry rejoining."));
+	else if (netgame && joindelay > 2 * (tic_t)cv_joindelay.value * TICRATE)
+		SV_SendRefuse(node, va(M_GetText("Too many people are connecting.\nPlease wait %d seconds and then\ntry rejoining."),
+			(joindelay - 2 * cv_joindelay.value * TICRATE) / TICRATE));
 	else
 	{
 #ifndef NONET
@@ -3670,6 +3681,7 @@ static void HandleConnect(SINT8 node)
 				DEBFILE("send savegame\n");
 			}
 			SV_AddWaitingPlayers(names[0], names[1]);
+			joindelay += cv_joindelay.value * TICRATE;
 			player_joining = true;
 		}
 #else
@@ -5038,12 +5050,21 @@ void NetUpdate(void)
 				hu_resynching = true;
 		}
 	}
+
 	Net_AckTicker();
+
 	// Handle timeouts to prevent definitive freezes from happenning
 	if (server)
+	{
 		for (i = 1; i < MAXNETNODES; i++)
 			if (nodeingame[i] && freezetimeout[i] < I_GetTime())
 				Net_ConnectionTimeout(i);
+
+		// In case the cvar value was lowered
+		if (joindelay)
+			joindelay = min(joindelay - 1, 3 * cv_joindelay.value * TICRATE);
+	}
+
 	nowtime /= NEWTICRATERATIO;
 	if (nowtime > resptime)
 	{
@@ -5051,6 +5072,7 @@ void NetUpdate(void)
 		M_Ticker();
 		CON_Ticker();
 	}
+
 	SV_FileSendTicker();
 }
 
diff --git a/src/d_clisrv.h b/src/d_clisrv.h
index 7e5061ff2..463240a2a 100644
--- a/src/d_clisrv.h
+++ b/src/d_clisrv.h
@@ -515,7 +515,7 @@ extern UINT32 realpingtable[MAXPLAYERS];
 extern UINT32 playerpingtable[MAXPLAYERS];
 extern tic_t servermaxping;
 
-extern consvar_t cv_allownewplayer, cv_joinnextround, cv_maxplayers, cv_rejointimeout;
+extern consvar_t cv_allownewplayer, cv_joinnextround, cv_maxplayers, cv_joindelay, cv_rejointimeout;
 extern consvar_t cv_resynchattempts, cv_blamecfail;
 extern consvar_t cv_maxsend, cv_noticedownload, cv_downloadspeed;
 
diff --git a/src/d_netcmd.c b/src/d_netcmd.c
index 1fd53499a..dfc7351f5 100644
--- a/src/d_netcmd.c
+++ b/src/d_netcmd.c
@@ -573,6 +573,7 @@ void D_RegisterServerCommands(void)
 
 	// d_clisrv
 	CV_RegisterVar(&cv_maxplayers);
+	CV_RegisterVar(&cv_joindelay);
 	CV_RegisterVar(&cv_rejointimeout);
 	CV_RegisterVar(&cv_resynchattempts);
 	CV_RegisterVar(&cv_maxsend);