Added client detection of server protocol from challenge message.

Tweaked client handling of "Server is version x.xx" server rejection messages.
Client now sends info requests to servers with both KMQ2 and stock Q2 protocol versions.
Client now ignores server "wrong version" status messages.
Added server sending protocol version in challenge message.

client/cl_main.c

@@ -888,7 +888,7 @@ void CL_SendConnectPacket (void)
 
 	// if in compatibility mode, lie to server about this
 	// client's protocol, but exclude localhost for this.
-	sendProtocolVersion = ((cl_servertrick->integer != 0) && strcmp(cls.servername, "localhost")) ? OLD_PROTOCOL_VERSION : PROTOCOL_VERSION;
+	sendProtocolVersion = ((cl_servertrick->integer != 0) && (strcmp(cls.servername, "localhost") != 0)) ? OLD_PROTOCOL_VERSION : PROTOCOL_VERSION;
 
 	Netchan_OutOfBandPrint (NS_CLIENT, adr, "connect %i %i %i \"%s\"\n", sendProtocolVersion, port, cls.challenge, Cvar_Userinfo() );
 }
@@ -1304,6 +1304,14 @@ void CL_ParseStatusMessage (void)
 
 	s = MSG_ReadString(&net_message);
 
+	// Catch wrong version reply from server
+	if (s && strstr(s, "wrong version")) {
+		// The "wrong version" reply has been removed from most Q2 servers
+		// due to exploitability.  So we can just ignore it if we get one,
+		// as we're sending both stock Q2 and KMQ2 protocol versions at once.
+		return;
+	} 
+
 	Com_Printf ("%s\n", s);
 	UI_AddToServerList (net_from, s);
 }
@@ -1323,7 +1331,7 @@ extern netadr_t global_adr_server_netadr[16];
 
 void CL_PingServers_f (void)
 {
-	int			i, sendProtocolVersion;
+	int			i;
 	netadr_t	adr;
 	char		name[32];
 	char		*adrstring;
@@ -1332,10 +1340,6 @@ void CL_PingServers_f (void)
 
 	NET_Config (true);		// allow remote
 
-	// if the server is using the old protocol,
-	// lie to it about this client's protocol
-	sendProtocolVersion = (cl_servertrick->integer != 0) ? OLD_PROTOCOL_VERSION : PROTOCOL_VERSION;
-
 	// send a broadcast packet
 	Com_Printf ("pinging broadcast...\n");
 
@@ -1361,7 +1365,9 @@ void CL_PingServers_f (void)
         
         memcpy(&global_adr_server_netadr[i], &adr, sizeof(global_adr_server_netadr));
 
-		Netchan_OutOfBandPrint (NS_CLIENT, adr, va("info %i", sendProtocolVersion));
+		// Send both protocol versions, we'll get a reply from one or the other
+		Netchan_OutOfBandPrint (NS_CLIENT, adr, va("info %i", OLD_PROTOCOL_VERSION));
+		Netchan_OutOfBandPrint (NS_CLIENT, adr, va("info %i", PROTOCOL_VERSION));
 	}
 
 	noudp = Cvar_Get ("noudp", "0", CVAR_NOSET);
@@ -1370,7 +1376,9 @@ void CL_PingServers_f (void)
         global_udp_server_time = Sys_Milliseconds() ;
 		adr.type = NA_BROADCAST;
 		adr.port = BigShort(PORT_SERVER);
-		Netchan_OutOfBandPrint (NS_CLIENT, adr, va("info %i", sendProtocolVersion));
+		// Send both protocol versions, we'll get a reply from one or the other
+		Netchan_OutOfBandPrint (NS_CLIENT, adr, va("info %i", OLD_PROTOCOL_VERSION));
+		Netchan_OutOfBandPrint (NS_CLIENT, adr, va("info %i", PROTOCOL_VERSION));
 	}
 
 	noipx = Cvar_Get ("noipx", "0", CVAR_NOSET);
@@ -1379,14 +1387,16 @@ void CL_PingServers_f (void)
         global_ipx_server_time = Sys_Milliseconds() ;
 		adr.type = NA_BROADCAST_IPX;
 		adr.port = BigShort(PORT_SERVER);
-		Netchan_OutOfBandPrint (NS_CLIENT, adr, va("info %i", sendProtocolVersion));
+		// Send both protocol versions, we'll get a reply from one or the other
+		Netchan_OutOfBandPrint (NS_CLIENT, adr, va("info %i", OLD_PROTOCOL_VERSION));
+		Netchan_OutOfBandPrint (NS_CLIENT, adr, va("info %i", PROTOCOL_VERSION));
 	}
 }
 //</<serverping>>
 #else
 void CL_PingServers_f (void)
 {
-	int			i, sendProtocolVersion;
+	int			i;
 	netadr_t	adr;
 	char		name[32];
 	char		*adrstring;
@@ -1398,16 +1408,14 @@ void CL_PingServers_f (void)
 	// send a broadcast packet
 	Com_Printf ("pinging broadcast...\n");
 
-	// if the server is using the old protocol,
-	// lie to it about this client's protocol
-	sendProtocolVersion = (cl_servertrick->integer != 0) ? OLD_PROTOCOL_VERSION : PROTOCOL_VERSION;
-
 	noudp = Cvar_Get ("noudp", "0", CVAR_NOSET);
 	if (!noudp->integer)
 	{
 		adr.type = NA_BROADCAST;
 		adr.port = BigShort(PORT_SERVER);
-		Netchan_OutOfBandPrint (NS_CLIENT, adr, va("info %i", sendProtocolVersion));
+		// Send both protocol versions, we'll get a reply from one or the other
+		Netchan_OutOfBandPrint (NS_CLIENT, adr, va("info %i", OLD_PROTOCOL_VERSION));
+		Netchan_OutOfBandPrint (NS_CLIENT, adr, va("info %i", PROTOCOL_VERSION));
 	}
 
 	noipx = Cvar_Get ("noipx", "0", CVAR_NOSET);
@@ -1415,7 +1423,9 @@ void CL_PingServers_f (void)
 	{
 		adr.type = NA_BROADCAST_IPX;
 		adr.port = BigShort(PORT_SERVER);
-		Netchan_OutOfBandPrint (NS_CLIENT, adr, va("info %i", sendProtocolVersion));
+		// Send both protocol versions, we'll get a reply from one or the other
+		Netchan_OutOfBandPrint (NS_CLIENT, adr, va("info %i", OLD_PROTOCOL_VERSION));
+		Netchan_OutOfBandPrint (NS_CLIENT, adr, va("info %i", PROTOCOL_VERSION));
 	}
 
 	// send a packet to each address book entry
@@ -1435,7 +1445,9 @@ void CL_PingServers_f (void)
 		if (!adr.port)
 			adr.port = BigShort(PORT_SERVER);
 
-		Netchan_OutOfBandPrint (NS_CLIENT, adr, va("info %i", sendProtocolVersion));
+		// Send both protocol versions, we'll get a reply from one or the other
+		Netchan_OutOfBandPrint (NS_CLIENT, adr, va("info %i", OLD_PROTOCOL_VERSION));
+		Netchan_OutOfBandPrint (NS_CLIENT, adr, va("info %i", PROTOCOL_VERSION));
 	}
 }
 #endif
@@ -1512,7 +1524,7 @@ void CL_ConnectionlessPacket (void)
 	Com_Printf ("%s: %s\n", NET_AdrToString (net_from), c);
 
 	// server connection
-	if (!strcmp(c, "client_connect"))
+	if ( !strcmp(c, "client_connect") )
 	{
 		if (cls.state == ca_connected)
 		{
@@ -1549,14 +1561,14 @@ void CL_ConnectionlessPacket (void)
 	}
 
 	// server responding to a status broadcast
-	if (!strcmp(c, "info"))
+	if ( !strcmp(c, "info") )
 	{
 		CL_ParseStatusMessage ();
 		return;
 	}
 
 	// remote command from gui front end
-	if (!strcmp(c, "cmd"))
+	if ( !strcmp(c, "cmd") )
 	{
 		if (!NET_IsLocalAddress(net_from))
 		{
@@ -1571,32 +1583,39 @@ void CL_ConnectionlessPacket (void)
 	}
 
 	// print command from somewhere
-	if (!strcmp(c, "print"))
+	if ( !strcmp(c, "print") )
 	{
-		char	thisVersionRejMsg[64];
+		char	thisVersionRejMsg[128], thisVersionRejMsg2[128];
 
 		s = MSG_ReadString (&net_message);
 		Com_Printf ("%s", s);
 
 		// catch wrong version reply from server here
 		Com_sprintf (thisVersionRejMsg, sizeof(thisVersionRejMsg), "You need KMQuake2 version %4.2f to play on this server.", VERSION);
-		if ( strstr(s, "Server is version 3.19") || strstr(s, "Server is version 3.2")	// stock Q2 3.19 / 3.2x rejection messages
+		Com_sprintf (thisVersionRejMsg2, sizeof(thisVersionRejMsg2), "Server is version %4.2f.", VERSION);
+		if ( strstr(s, thisVersionRejMsg) || strstr(s, thisVersionRejMsg2) )	// Same version of KMQ2
+		{
+			Com_DPrintf ("Wrong version reply received from KMQ2 server.  Reconnecting as protocol version %i.\n", PROTOCOL_VERSION);
+			Cvar_SetInteger ("cl_servertrick", 0);
+			CL_Reconnect_f ();
+		}
+		else if ( strstr(s, "Server is version 3.19") || strstr(s, "Server is version 3.2")	// stock Q2 3.19 / 3.2x rejection messages
 			|| strstr(s, "You need Quake II 3.19 or higher to play on this server.")	// R1Q2
 			|| strstr(s, "Unsupported protocol version") || strstr(s, "You need Quake 2 version 3.19 or higher.") )	// Q2Pro
 		{
+			Com_DPrintf ("Known wrong version reply received from server.  Reconnecting as protocol version %i.\n", OLD_PROTOCOL_VERSION);
 			Cvar_SetInteger ("cl_servertrick", 1);
-			Com_Printf ("Wrong version reply received from server.  Reconnecting as protocol version %i.\n", OLD_PROTOCOL_VERSION);
 			CL_Reconnect_f ();
 		}
-		else if ( strstr(s, thisVersionRejMsg) )	// Same version of KMQ2
+		else if ( strstr(s, "Server is version") )
 		{
-			Cvar_SetInteger ("cl_servertrick", 0);
-			Com_Printf ("Wrong version reply received from server.  Reconnecting as protocol version %i.\n", PROTOCOL_VERSION);
+			Com_DPrintf ("Unknown wrong version reply received from server.  Reconnecting as protocol version %i.\n", OLD_PROTOCOL_VERSION);
+			Cvar_SetInteger ("cl_servertrick", 1);
 			CL_Reconnect_f ();
 		}
-		else if ( strstr(s, "Server is version") )	// don't keep going if unknown version
+		else if ( strstr(s, "You need KMQuake2 version") )
 		{
-			Com_Printf ("Unknown wrong version reply received from server.  Disconnecting.\n");
+			Com_DPrintf ("Wrong version reply received from different-protocol KMQ2 server.  Disconnecting.\n");
 			SCR_EndLoadingPlaque ();
 			CL_Disconnect ();
 		}
@@ -1605,22 +1624,71 @@ void CL_ConnectionlessPacket (void)
 	}
 
 	// ping from somewhere
-	if (!strcmp(c, "ping"))
+	if ( !strcmp(c, "ping") )
 	{
 		Netchan_OutOfBandPrint (NS_CLIENT, net_from, "ack");
 		return;
 	}
 
 	// challenge from the server we are connecting to
-	if (!strcmp(c, "challenge"))
+	if ( !strcmp(c, "challenge") )
 	{
+		int			j, v;
+		char		*sc;
+		qboolean	hasCurProtcol = false, hasLegacyProtocol = false;
+
 		cls.challenge = atoi(Cmd_Argv(1));
+
+		// R1Q2 and Q2Pro put supported protocol versions in challenge.
+		// Parse for those here, and change cl_servertrick if needed.
+		if ( strcmp(cls.servername, "localhost") != 0 )
+		{
+			for (j = 2; j < Cmd_Argc(); j++)
+			{
+				sc = Cmd_Argv(j);
+				if ( !strncmp(sc, "p=", 2) )
+				{
+					sc += 2;
+					if (!sc[0]) {
+						continue;
+					}
+					for (;;)
+					{
+						v = atoi(sc);
+						if (v == PROTOCOL_VERSION) {
+							hasCurProtcol = true;
+						}
+						else if (v == OLD_PROTOCOL_VERSION) {
+							hasLegacyProtocol = true;
+						}
+						sc = strchr(sc, ',');
+						if (!sc) {
+							break;
+						}
+						sc++;
+						if (!sc[0]) {
+							break;
+						}
+					}
+					if (hasCurProtcol) {
+						Com_DPrintf ("Setting current protocol (%i) from server challenge.\n", PROTOCOL_VERSION);
+						Cvar_SetInteger ("cl_servertrick", 0);
+					}
+					else if (hasLegacyProtocol) {
+						Com_DPrintf ("Setting legacy protocol (%i) from server challenge.\n", OLD_PROTOCOL_VERSION);
+						Cvar_SetInteger ("cl_servertrick", 1);
+					}
+					break;
+				}
+			}
+		}
+
 		CL_SendConnectPacket ();
 		return;
 	}
 
 	// echo request from server
-	if (!strcmp(c, "echo"))
+	if ( !strcmp(c, "echo") )
 	{
 		Netchan_OutOfBandPrint (NS_CLIENT, net_from, "%s", Cmd_Argv(1) );
 		return;

kmquake2.txt

@@ -113,7 +113,7 @@ How To Run
 	mod's code to run, it must be compiled into a kmq2gamex86.dll (see end of file for
 	instructions).
 
-	To ping info from and connect to standard Quake2 (protocol 34) servers, add
+	To ensure connection to all standard Quake2 protocol (34) servers, add
 	
 	+set cl_servertrick 1
 	

kmquake2_changelog.txt

@@ -21,7 +21,8 @@ Changes as of v0.20 update 8:
 
 - Added support for quake2:// URLs.
 
-- Added client auto-reconnect with cl_servertrick set correspondingly when a known "wrong version" rejection message is received.
+- Added client detection of server protocol from challenge message.  Client also auto-reconnects with cl_servertrick
+	set correspondingly when a "wrong version" rejection message is received.
 
 - Added cel shading support.  Uses cvars r_celshading to enable, and r_celshading_width for line width (1-10).
 

server/sv_main.c

@@ -368,7 +368,8 @@ void SVC_GetChallenge (void)
 	}
 
 	// send it back
-	Netchan_OutOfBandPrint (NS_SERVER, net_from, "challenge %i", svs.challenges[i].challenge);
+//	Netchan_OutOfBandPrint (NS_SERVER, net_from, "challenge %i", svs.challenges[i].challenge);
+	Netchan_OutOfBandPrint (NS_SERVER, net_from, "challenge %i p=%i", svs.challenges[i].challenge, PROTOCOL_VERSION);
 }
 
 /*